Dissertations / Theses: 'Carezza'

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Schifino, Valente Ana Luisa. "Diagnostic imaging of the Loggerhead sea turtle (Caretta caretta)." Doctoral thesis, Universitat Autònoma de Barcelona, 2007. http://hdl.handle.net/10803/5744.

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The aims of this work are:
1. To provide the normal cervical and coelomic radiographic appearance of the Loggerhead sea turtle, in the dorso-ventral view, as well as other useful landmarks, to allow for correlation of shell scutes with internal anatomic structures.
2. To provide the normal radiographic anatomy of the limbs of the Loggerhead sea turtle in combination with data obtained from computed tomography - osteological, gross anatomical and histological data.
3. To describe the normal ultrasonographic appearance of cervical structures and coelomic organs of the Loggerhead sea turtle, and to provide the respective images of frozen cross-sections for anatomical reference.
4. To provide normal computed tomographic images of the vertebral column and coelomic structures of the Loggerhead sea turtle, by establishing reference standards for organ size and position in this species; to provide images of virtual tracheo-bronchoscopy and 3D reconstructions of the respiratory tract and bone structures.
5. To provide the normal magnetic resonance imaging (MRI) appearance of coelomic structures of Loggerhead sea turtles in T1 and T2-weighted scans via comparison with cross-sectional anatomic sections of this species.

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Margolis, William E. "Nesting Periodicity of Caretta caretta in Broward County, Florida." NSUWorks, 1993. http://nsuworks.nova.edu/occ_stuetd/352.

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The loggerhead sea turtle, Caretta caretta, is the most common sea turtle found nesting on Florida beaches. Burney and Mattison (1989) reported a trend towards increased loggerhead nesting in Broward County in 1989 during new and full moons. This trend was found at Hillsboro Beach in 1988 and in Broward County as a whole in 1989. These peaks in nesting activity were attributed to semilunar tidal cycles. In an effort to determine if semilunar tidal cycles do influence trends in daily loggerhead nesting density, daily loggerhead nests and total crawls (including nesting and non-nesting emergences) for the 1990 season (April 20- September 2) and for the peak of the 1990 season (May 30- July 27) were analyzed. Daily nest and total crawl counts were compared with variables based on moon phase, the nocturnal high tide time, and the rates of the incoming (flooding) and outgoing (ebbing) nocturnal high tides. There were 2,281 loggerhead nests and 4,206 total loggerhead crawls in Broward County during the entire season; there were 1,659 nests and 3,125 total crawls during the peak of the season (Burney and Mattison 1990). Comparisons were made using simple regression and correlation analyses, and indicated a trend towards increasing loggerhead emergences during the peak of the season when the nocturnal high tide was near 10 p.m.

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Bartol, Soraya M. "Auditory Evoked Potentials of the Loggerhead Sea Turtle (Caretta caretta)." W&M ScholarWorks, 1994. https://scholarworks.wm.edu/etd/1539617675.

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Nielsen, Janne Thoft. "Population Structure and the Mating System of Loggerhead Turtles (Caretta caretta)." Scholarly Repository, 2010. http://scholarlyrepository.miami.edu/oa_dissertations/507.

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Studies of the maternally inherited mitochondrial DNA in loggerhead sea turtles (Caretta caretta) demonstrate that females are philopatric, returning to nest in the region where they hatched. Eleven genetic stocks of maternal lineages have been identified in the Atlantic Ocean. An analysis of the conventionally-used 380 bp of the mitochondrial control region of a sample of individuals from the genetic stock of loggerheads in Mexico (N = 175) revealed 13 haplotypes. When a longer sequence read of 815 bp was analyzed, 17 haplotypes were uncovered. In the genetic stock of loggerheads in northwestern Florida (N = 25), three haplotypes were identified with both control region sequence lengths. Based on the currently known distributions of the three long CC-A1 and CC-A2 haplotypes, two of each are unique to Mexico. This makes the longer sequence reads useful for stock identification. Within Mexico, there was evidence of significant population structuring between Cozumel and the northern region of the sampling area on mainland Mexico (pairwise ϕST = 0.1003, p = 0.0197), but not after Bonferroni correction. A direct comparison of female and male nuclear microsatellite genotypes indicated male-biased dispersal between Mexico and northwestern Florida. Within Mexico, microsatellite analysis indicated significant structuring of females between sampling years and between the northern and the southern region of the sampling area on the mainland. Consequently, this genetic stock, while perhaps not in equilibrium, shows signs of female natal homing. An analysis of clutches indicated that significantly more clutches in Mexico had multiple paternity compared to the northwestern Florida (66% and 23%, respectively). The frequency of multiple paternity was not correlated with female abundance, nest density or sex ratio of reproductively successful individuals. There was no evidence of females benefiting through increased reproductive success from multiple paternity. This is consistent with other studies of sea turtles.

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Durland, Donahou Allison. "Loggerhead Sea Turtle (Caretta caretta) Hatchling Disorientation in Broward County, Florida." NSUWorks, 2014. http://nsuworks.nova.edu/occ_stuetd/15.

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Hatchling disorientation after emergence is a major factor impacting sea turtle populations. This study utilized data from over 1,200 Florida Fish and Wildlife Conservation Commission (FWC) Marine Turtle Disorientation Report forms from years 2006 to 2011 to assess changes in the severity and locations of disorientation events and the impact of municipal beach lighting ordinances. While the FWC forms were completed for all sea turtle species observed, this study focused only on loggerhead sea turtles (Caretta caretta). A Disorientation Severity Index (DSI) was derived from the number of hatchlings and the direction of their tracks leaving the nests to evaluate the changes in disorientation over six years in Broward County. The FWC forms provide a much larger database for the analysis of hatchling disorientation patterns and trends than can be derived from the more precise, but labor intensive, Hatchling Orientation Index (HOI) survey method of Witherington et al. (1996). This research differs from prior work by focusing on the information provided in the FWC Marine Turtle Disorientation Report forms; using each individual disorientation to assess changes in the severity of hatchling disorientations over time. Prior work has not used the FWC forms for analysis. Significant differences were found for average DSI between years and locations. Overall, DSI decreased significantly from 2006 to 2011 in Hillsboro Beach, Pompano Beach, Lauderdale-by-the-Sea, Fort Lauderdale, and Hollywood. This might be due to increased compliance with lighting ordinances. In addition, disorientation hotspots were identified and the DSI in these hotspots decreased significantly in central and south Fort Lauderdale, Pompano Beach, and Lauderdale-by-the-Sea. Hotspots were visually identified as R-Zone ranges with higher numbers of disorientations than in other ranges (Fig. 6). Artificial beach illumination is very prevalent in Broward County. However, there was no significant relationship between the number of types of lights that were recorded on the FWC forms and DSI. Disorientations seemed to be clustered within hotspots with known lighting issues. Management strategies should use these analyses to reassess loggerhead recovery plans to reduce disorientation hotspots and increase hatchling recruitment.

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Klinger, Ruth Ellen. "Age and Growth of Juvenile Loggerheads (Caretta caretta), from Chesapeake Bay." W&M ScholarWorks, 1988. https://scholarworks.wm.edu/etd/1539617582.

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Lenz, Ana Júlia. "Estimativa de idade e crescimento de Caretta caretta e Chelonia mydas no litoral sul do Brasil através de esqueletocronologia." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2013. http://hdl.handle.net/10183/143573.

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As tartarugas marinhas são animais de vida longa, com maturação sexual tardia, grandes áreas de vida e ampla distribuição geográfica. Sofrem diversos impactos ao longo de seu ciclo de vida, o que contribui para estarem globalmente ameaçadas de extinção. Estes animais apresentam um ciclo de vida complexo, que consiste de estágios de desenvolvimento segregados espacialmente e temporalmente, envolvendo mudanças marcantes de habitat e dieta. O litoral sul do Brasil não apresenta áreas próprias para a desova de tartarugas marinhas, mas é utilizado regularmente por algumas espécies como área de alimentação, pelo menos em alguma etapa do seu desenvolvimento. As espécies registradas com mais frequência na região e analisadas neste estudo são a tartaruga-cabeçuda, Caretta caretta, e a tartaruga-verde, Chelonia mydas. Apesar de serem animais ameaçados de extinção, diversos aspectos do ciclo de vida das tartarugas marinhas permanecem pouco conhecidos. Idade e crescimento são parâmetros importantes para o melhor entendimento da história de vida das espécies e elaboração de estratégias de manejo. Espécimes encontrados encalhados mortos durante um período de 16 anos na costa do Rio Grande do Sul foram utilizados para realizar estimativas de idade e crescimento através de esqueletocronologia. Esta técnica oferece o potencial para uma rápida e ampla caracterização de parâmetros de idade e crescimento de uma população. Os resultados mostram que ambas as espécies são encontradas nesta região durante a fase juvenil, logo após o recrutamento do ambiente oceânico para o ambiente nerítico, que ocorre por volta de 12 anos e comprimentos de carapaça maiores que 55 cm nas tartarugas-cabeçudas e aproximadamente 30 cm e 3 anos nas tartarugas-verdes. As tartarugas-cabeçudas analisadas tiveram idades estimadas entre 10 e 29 anos e comprimentos da carapaça entre 53 e 101 cm e as tartarugas-verdes apresentaram entre 2 e 13 anos e tamanhos entre 31 e 62 cm. Taxas de crescimento são inversamente relacionadas à idade e ao tamanho, apresentando grande variação individual. Os resultados corroboram a ideia de que o litoral sul do Brasil é uma importante área de desenvolvimento para juvenis neríticos das duas espécies em questão, sendo uma região de extrema importância para a conservação das tartarugas marinhas no Atlântico sul ocidental.
Sea turtles are long-lived marine reptiles with late sexual mature, large home-ranges and wide geographic distribution. They are exposed to many impacts over its life cycle which contributes to their worldwide threatened status. Sea turtles present a complex life cycle of development stages that are segregated spatially and temporally involving marked changes in diet and habitat. The south coast of Brazil don‟t present nesting areas but is used by some species as feeding area at least in any stage of its development. The most abundant species in this region and the turtles analyzed in this study are the loggerhead and the green turtle. Although threatened worldwide, many aspects of life cycle of sea turtles remain poorly known. Age and growth are important parameters to understand life history and to develop management strategies. Specimens stranded during a period of 16 years along the coast of the State of Rio Grande do Sul were used to estimate age and growth by skeletochronology. This technique offers the potential to a quick and wide characterization of age and growth parameters of a population. The results show that both species live in this region during juvenile stage, just after recruitment from the oceanic environment to the neritic environment. The recruitment occurs about 12 years and length greater than 55 cm on loggerhead and from 30 cm and 3 years on green turtles. The loggerhead turtles have estimated age between 10 and 29 years and carapace length between 53 and 101 cm and green turtles presents between 2 and 13 years and length between 31 and 62 cm. Growth rates were inversely related to length and age. The results corroborate the idea that the south Brazilian coast is an important development area to neritic juveniles of both species, being a region of extreme importance to sea turtle conservation in the southwestern Atlantic.

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Bertuccio, Valentina. "Genetic patterns in recovered specimens of Caretta caretta from the Adriatic Sea." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2015. http://amslaurea.unibo.it/8374/.

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The Adriatic Sea is considered a feeding and developmental area for Mediterranean loggerhead turtles, but this area is severely threatened by human impacts. In the Adriatic Sea loggerhead turtles are often found stranded or floating, but they are also recovered as by-catch from fishing activities. Nevertheless, information about population structuring and origin of individuals found in the Adriatic Sea are still limited. Cooperation with fishermen and a good network of voluntary collaborators are essential for understanding their distribution, ecology and for developing conservation strategies in the Adriatic Sea. In this study, a comparative analysis of biometric data and DNA sequence polymorphism of the long fragment of the mitochondrial control region was carried out on ninety-three loggerheads recovered from three feeding areas in the Adriatic Sea: North-western, North-eastern and South Adriatic. Differences in turtles body sizes (e.g. Straight Carapace Length) among the three recovery areas and relationship between SCL and the type of recovery were investigated. The origin of turtles from Mediterranean rookeries and the use of the Adriatic feeding habitats by loggerheads in different life-stages were assessed to understand the migratory pathway of the species. The analysis of biometric data revealed a significant difference in turtle sizes between the Southern and the Northern Adriatic. Moreover, size of captured turtles resulted significantly different from the size of stranded and floating individuals. Actually, neritic sub-adults and adults are more affected by incidental captures than juveniles because of their feeding behavior. The Bayesian mixed-stock analysis showed a strong genetic relationship between the Adriatic aggregates and Mediterranean rookeries, while a low pro¬portion of individuals of Atlantic origin were detected in the Adriatic feeding grounds. The presence of migratory pathways towards the Adriatic Sea due to the surface current system was reinforced by the finding of individuals bearing haplotypes endemic to the nesting populations of Libya, Greece and Israel. A relatively high contribution from Turkey and Cyprus to the Northwest and South Adriatic populations was identified when the three sampled areas were analyzed independently. These results have to be taken in account in a conservative perspective, since coastal hazards, affecting the population of turtles feeding in the Adriatic Sea may also affect the nesting populations of the Eastern Mediterranean with a unique genetic pattern.

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9

Badillo, Amador Fco Javier. "Epizoítos y parásitos de la tortuga boba (Caretta caretta) en el Mediterráneo Occidental." Doctoral thesis, Universitat de València, 2007. http://hdl.handle.net/10803/10350.

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En el presente trabajo se ha realizado un estudio de los epizoítos y endoparásitos de la tortuga boba (Caretta caretta) en el Mediterráneo occidental. En el apartado de epizoítos, se ha encontrado 39 taxones pertenecientes a los filos Cnidaria, Annelida, Crustacea, Mollusca y Ectoprocta. El hallazgo de algunas de estas especies suscita cierto interés por ser de nueva aparición en el Mediterráneo o por constituir nuevos registros como epizoítos de tortugas marinas en el Mediterráneo o a nivel mundial. Se halló un copépodo harpacticoide perteneciente a la familia Balaenophilidae que muestra rasgos morfométricas propios de una nueva especie, denominada aquí, por el momento, Balaenophilus sp. Asimismo, se ha redescrito el copépodo especialista de C. caretta Balaenophilus umigamecolus a partir de ejemplares procedentes de Japón, tras hallarse nuevos caracteres y corregirse algunos otros respecto a la descripción original. Además, se ha estudiado el hábitat y la alimentación de los copépodos del género Balaenophilus para averiguar la asociación existente con sus hospedadores: B. unisetus, especialista de cetáceos misticetos, y Balaenophilus sp., la especie encontrada por nosotros en el Mediterráneo occidental. El contenido digestivo y el estudio histopatológico de lesiones asociadas a Balaenophilus sp., sugiere que ambas especies se alimentan de tejido del hospedador, compuesto en su mayor parte por queratina. Su asociación exclusiva con ballenas y tortugas marinas podría deberse a su habilidad para explotar este recurso, escaso en el medio marino. Asimismo, se ha realizado por primera vez un estudio cuantificado de algunos determinantes de la diversidad de epizoítos y se ha intentado cuantificar el efecto de la metodología del muestreo sobre los resultados. El presente estudio muestra que la comunidad potencial de epizoítos de cualquier individuo de C. caretta en el Mediterráneo occidental está compuesta por un grupo de especialistas y un conjunto mas variable de generalistas de sustratos flotantes. A diferencia de otros estudios, el análisis sobre las interacciones bióticas de colonización muestra asociaciones globales positivas en especialistas y neutras en las especies no especialistas. No hemos hallado relaciones de exclusión entre especies. La presencia de algas del género Polysiphonia determina la presencia de un núcleo de 3 especialistas frecuentes, Caprella andreae, Hyale grimaldii y Hexapleomera robusta. También se ha confirmado la relación positiva entre la talla de las tortugas y el número de especies de epizoitos. Se han hallado 10 especies de helmintos, todos en el tracto digestivo: 8 trematodos digeneos (Enodiotrema megachondrus, Calycodes anthos, Hemiuroidea spp., Pachypsolus irroratus, Rhytidodes gelatinosus, Orchidasma amphiorchis, Plesiochorus cymbiformis, Pleurogonius trigonocephalus) y 2 nematodos (Kathlania leptura y Anisakis sp. tipo I). Todos ellos son especialistas de tortugas marinas excepto el digeneo Hemiuroidea spp. y el nematodo Anisakis sp. tipo I, considerados accidentales. El estudio de la diversidad de las comunidades helmínticas gastrointestinales de C. caretta revela que éstas constituyen un sistema aislado para el intercambio de parásitos con otros vertebrados marinos. En el Mediterráneo occidental la tortuga boba debe "sostener" su fauna de parásitos especialistas puesto que tampoco los intercambia con otras especies de tortugas marinas. De hecho, las infracomunidades están compuestas por especialistas con prevalencias muy bajas. Esto podría explicarse por el carácter ectotérmico de las tortugas, su gran vagilidad y su amplia dieta. El análisis comparativo de la composición y estructura de las comunidades helmínticas de dos grupos de tortugas de distinto origen (decomisadas y varadas) no reveló diferencias, a pesar de que su dieta sí mostraba diferencias significativas, al menos en dos grupos de presas de gran importancia numérica, los tunicados pelágicos y los teleósteos. Se sugiere que ello se debe a que los digeneos especialistas de las tortugas bobas utilizan gasterópodos y/o bivalvos como hospedadores intermediarios.
This study focussed on the epibionts and endoparasitic fauna in the Loggerhead turtle (Caretta carretta) in the Western Mediterranean.39 taxons belonging 5 epizoite phyla were found. Some of these findings are of special interest since these species have never recorded in the Mediterranean or as epizoites of marine turtles.A comparative morphometric study between a harpacticoid copepod from our samples and Balaenophilus umigamecolus from Japan revealed differences indicative for a new species. Also, an updated description of B. umigamecolus, first described in Japan, was made.Also, a study was carried out in order to find out the type of association between the species of genus Balaenophilus and their hosts, suggesting that these species feed on host tissue, formed mainly of keratin.At the same time, a quantitative study of some limiting factors of the epizoites diversity in C. caretta was carried out, attempting to quantify the effect of the sampling methodology on the results. Our study shows that the potential community of epizoites of individuals of C. caretta in the Western Mediterranean is composed by a group of specialists and a group of non specific fouling species. In contrast to other studies, positive associations were found between the biotic colonization interactions in specialists and neutral associations in the case of non specialist. We did not find exclusive interactions between species. Positive relation between turtle size and season, with number of species of epizoites, was detected. A total of 10 species of helminths were found, 8 digenean and 2 nematodes, all of them in the digestive tract. Except Hemiuroidea spp. and Anisakis sp., both accidental, all species are marine turtle specialists. The gastrointestinal helminth infracommunities of C. caretta are very depauperate, being formed by species that appear in low prevalence, despite their specialist status. The comparative analysis of composition and structure of helminth communities of turtles from two different origins of the Western Mediterranean did not reveal differences, although their diet did show significant differences. It is suggested that this pattern is possibly explained because sea turtle specialist digeneans use gastropods and/or bivalves as intermediate hosts.

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Bellmund, Sarah A. "Assessing Environmental Stress on the Loggerhead Sea Turtle (Caretta caretta) in Virginia Waters." W&M ScholarWorks, 1988. https://scholarworks.wm.edu/etd/1539617587.

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11

Jones, William Mason. "Physical Parameters Affecting Incubating Temperatures in Loggerhead Sea Turtles, Caretta caretta, in Virginia." W&M ScholarWorks, 1998. https://scholarworks.wm.edu/etd/1539617732.

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Detailed physical profile of eight transplanted loggerhead sea turtle, Caretta caretta, nests were obtained from Virginia and northeastern North Carolina and reburied in Back Bay National Wildlife Refuge (BBNWR), Virginia Beach, Virginia during the summers of 1987, '88, and '89 to determine if the physical location of the egg within the nest had an affect on sex determination. Transplanted nests were reburied in sandy substrate at a depth of 15-60 em on south facing dunes, and a Campbell Scientific data-logger logged synchronously environmental data. The following data were collected: temperatures at various locations within a nest, net absorbed radiation, ambient temperature, rainfall (em), substrate moisture content, and tide cycles. To understand the determination of sex, a time series analyses was employed to explain the variability, the periodicity, and the irregular oscillations of the temperature data. The regression analysis, using the periodicity of the spring/neap cycles, indicated a significant diurnal and spring/neap tidal affect. The 29.5 and 14.7 day cycle were significant. In addition, a delayed heating affect on the dune temperatures was noted 3-5 days after the lowest tides of the full and new moon cycles which consistently occurred at approximately 3:00P.M. Temperature records in nests at BBNWR were consistent with those producing a predominance of male hatchlings (<28.0C). Temperatures which produced females did exist, but were infrequent. Maximum beach face heating resulted in elevating · temperatures from 1-3C at the 37cm depths. This affect could produce females in late summer and early fall. Physical parameters varied with depth, time of day, and season (summer/fall). The results of this study are important to conservation of sea turtles because they contribute much to the knowledge of how nest manipulation may control sex ratios. Using the approach developed in this study, a mathematical model to predict sex ratios could be developed that would be applicable for various physical regimes found on most major nesting beaches of various sea turtles around the world.

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Guerrini, Romina. "Sopravvivenza di Lactobacillus sakei in condizioni di carenza nutrizionale." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2019. http://amslaurea.unibo.it/18092/.

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La fermentazione nei salami è un processo complesso che porta alla formazione di numerosi composti che determinano le caratteristiche organolettiche dei prodotti finiti. I principali microrganismi responsabili sono i batteri lattici, tra cui Lactobacillus sakei è la specie dominante. Esso è ampiamente utilizzato come coltura starter per la produzione di salumi grazie alla sua capacità di crescere in condizioni di stress: alte concentrazioni di sale, carenza nutrizionale, bassi valori di pH e di attività dell’acqua. L. sakei, passando dalla via omolattica a quella eterolattica, ha la capacità di adattarsi e sopravvivere anche quando le fonti di zuccheri esosi sono esaurite, ricavando energia da fonti alternative come i pentosi o attivando vie metaboliche secondarie che utilizzano come substrati gli aminoacidi. In questo elaborato un ceppo commerciale di L. sakei, utilizzato per la produzione di salami, è stato inoculato in un terreno sintetico con glucosio o ribosio a concentrazioni ottimali per la crescita (25 mM) o ridotte (2.5 mM), per simulare una carenza nutrizionale. È stato valutato l’effetto dei diversi zuccheri sulla sua capacità di crescita e sulle risposte metaboliche, in termini di accumulo di acidi organici e consumo di aminoacidi. I risultati hanno evidenziato un consumo selettivo di alcuni aminoacidi (tra cui arginina, serina) in funzione delle caratteristiche del terreno utilizzato, indicando un’attivazione di vie metaboliche alternative in condizioni di stress nutrizionale. Anche l’accumulo di acido lattico e acetico varia in base allo zucchero presente. Inoltre, l’analisi citofluorimetrica per valutare la vitalità cellulare e lo stato delle membrane cellulari ha evidenziato un’estrema variabilità della risposta fisiologica, che spiega l’adattamento di L. sakei alla matrice carnea. Dal punto di vista tecnologico, i risultati ottenuti possono essere utili per ottimizzare l’impiego di tale microrganismo nell'industria dei salumi fermentati.

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Gibson, Hartwig Jennifer M. "Effects of Beach Renourishment on Loggerhead Sea Turtle (Caretta caretta) Nesting and Hatching Parameters." NSUWorks, 2002. http://nsuworks.nova.edu/occ_stuetd/303.

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Loggerhead sea turtles (Caretta caretta) deposit eggs on 1250 km of Florida beaches in underground egg chambers. Florida beaches host more than 20,000 loggerhead sea turtles per year, which comprise 90% of the total nesting population of the United States. Coastal erosion has caused depletion of much of the suitable nesting habitat. Beaches in Florida also support various developments, homes, recreational activities, and serves other environmental networks. This erosion can be attributed to coastal development, global warming and the rise in sea level. Due to economic, recreational, safety, and environmental conservation reasons one mechanism, beach preservation has become necessary. Beach renourishment, adding sand to the beach via dredging,accoplishes this. The source of sand, the time of renourishment, and the biological, chemical and geological parameters of the sand must all be considered to minimize ecological disturbances. The impact of three beach renourishment projects were examined that occurred in Broward County, John U. Lloyd State Park (1989), Hollywood Beach (1990), and Hillsboro Beach (1998). Nesting success, incubation time, and hatching success were analyzed via one-way ANOVA and slope tests. Nest depth and emergence success were analyzed when the data were available. Pre-nourishment data were used to analyze the nesting conditions prior to erosion. The post-nourishment data were compared to test the impacts of renourishment on nesting and hatching parameters. On all three beaches, the highest nesting success was found before the renourishment. The success dropped the year of the renourishment. The number of adult female emergences did increase the year follwing the renourishment, due to the increased beach width. Incubation times are decreased during the year following the renourishment. However, this data as well as the nest depth data on all three beaches strongly related to the weather data. The hatching success data could not be conclusively linked with the renourishment. The Hillsboro Beach project only indicated a decrease in the hatching success the year after the renourishment. The emergence success was slightly lower the year following renourishment, however not significantly so. While beach renourishment did affect some aspects loggerhead sea turtles' nesting parameters, the effects were minimal and did not appear to be long term. In most cases, the data had returned to pre-nourishment levels within three years after the renourishment. As renourishment has become beneficial in order to restore nesting habitat, it is important to study ways to protect the sand that is placed on the beaches. According to the three projects in Broward County, Florida, beach renourishment does appear to be a viable solution for the erosion problem. Since this is only a short term solution to a reoccuring problem, designing a complete beach maintainence plan could ensure the continuation of the beaches.

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Trocini, Sabrina. "Health assessment and hatching success of two Western Australian loggerhead turtle (Caretta caretta) populations." Thesis, Trocini, Sabrina (2013) Health assessment and hatching success of two Western Australian loggerhead turtle (Caretta caretta) populations. PhD thesis, Murdoch University, 2013. https://researchrepository.murdoch.edu.au/id/eprint/18114/.

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Most of the existing sea turtle populations worldwide are in decline, and loggerhead turtles (Caretta caretta), in particular, are listed as Endangered. The loggerhead nesting population in Western Australia is the largest nesting population in Australia and one of the largest in the Indian Ocean and the world. This research project investigated hatching success and health, two critical aspects for loggerhead turtle conservation and management, on two important nesting sites in Western Australia: Turtle Bay on Dirk Hartog Island and Bungelup Beach in Cape Range National Park. This project undertook an inter-disciplinary approach encompassing the disciplines of conservation medicine, ecology and epidemiology to investigate questions about sea turtle conservation that could not be addressed by any of these disciplines alone. Morphological and reproductive measurements were collected during two nesting seasons, between 2006 and 2008, obtaining important baseline reproductive data about the Western Australian population. It was found that the presence of deformed and yolkless eggs was associated with smaller clutch size. At the same time several biotic and abiotic factors were assessed in relation to embryonic and hatchling mortality. Hatching success was significantly reduced by high temperatures during the pre-emergent period, the presence of roots in the nest and nest location along the beach. Results suggest that bacterial contamination of sand on the high nesting density beach sectors may, in part, be responsible for the differences in hatching success along the beach. High nest temperature during the pre-emergent period also significantly reduced emergence success and influenced emergence patterns and duration. Prolonged emergence duration, associated with increased nest temperatures, may further reduce hatchling survival due to diminished energy reserves and increased risk of predation. On the mainland nesting site, Bungelup Beach, predation of eggs and hatchlings severely limited reproductive success with over 80% of the monitored nests showing signs of partial or complete predation. In contrast with that reported in the literature, ghost crabs (Ocypode spp) were the main predator at this site and the first among the identified predators to dig into nests. Perentie (Varanus giganteus) and introduced foxes (Vulpes vulpes) also predated on eggs and hatchlings, making the level of predation recorded unlikely to be sustainable in the long term. Health monitoring of the nesting populations enabled the determination of baseline blood health parameters and toxin levels in blood. Two cases of fibropapillomatosis were confirmed for the first time in Western Australian loggerhead turtles. Changes in the leukogram and some biochemical parameters were detected in association with the presence of barnacles, in particular burrowing barnacles. In order to establish the connection between the nesting turtles’ health and reproductive success, maternal health indices were compared to hatching success and reproductive output. Several blood health parameters, including alpha and gamma proteins, iron, zinc and vitamin E levels, were correlated with hatching success or clutch size, suggesting that these parameters influence reproduction in loggerhead turtles. Additionally, sea turtles with reproductive abnormalities, such as soft-shelled or deformed eggs, had higher blood mercury levels than turtles without any egg or clutch abnormalities. This finding raises important questions about the toxic effect of mercury, at low blood concentrations, on sea turtle reproduction. During the health assessment, a novel intraerythrocytic protozoal parasite species, similar to a malaria parasite (Haemoproteus and Plasmodium spp), was identified for the first time in sea turtles and was described through the use of light microscopy and diagnostic molecular techniques. The phylogenetic analysis indicated that this new parasite is closely related to other haemosporidia isolated from chelonians, but is well separated from malaria parasites isolated from other hosts (e.g. mammals, birds and other reptiles). This parasite appears to be largely benign. Although parasitaemia was low in all infected individuals, further studies are required to assess the potential impact of this haemoparasite on sea turtle fitness. In conclusion, this study provided further understanding of factors affecting reproductive success, identified threats to the Western Australian nesting population whilst at the same time enabling assessment of the general health of nesting loggerhead turtles in Western Australia.

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Åsblom, Fanny. "Carema Care? : En retorisk argumentations- och kriskommunikationsanalys av vårdföretaget Carema Care." Thesis, Uppsala universitet, Litteraturvetenskapliga institutionen, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-175713.

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Uppsatsen behandlar vårdföretaget Carema Cares två bloggar som skapades i och med krisen som uppstod kring företaget år 2011. Detta görs genom en granskning av argumentationen Carema Care för på bloggarna utifrån kriskommunikationsstrategier och retoriska strategier.

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D'ANDREA, SETTIMIO. "Correlati della carenza androgenica negli uomini affetti da mielolesione cronica." Doctoral thesis, Università degli Studi dell'Aquila, 2021. http://hdl.handle.net/11697/161795.

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Il riscontro di bassi livelli di testosterone durante la fase acuta di una lesione midollare è un dato consolidato da decenni nella Letteratura Internazionale. I meccanismi patogenetici di questo evento sono ben noti e comuni a tutti gli stadi acuti di patologie ad interessamento sistemico. Nell’ultimo decennio è emerso come lo stato di carenza androgenica si riscontra con un’alta prevalenza anche nella fase cronica della lesione midollare. Con l’allungarsi della vita media di questi individui, per il miglioramento delle cure ricevute, il medico che ha in cura uomini con mielolesione cronica deve sempre più frequentemente confrontarsi con questo aspetto emergente. Oltre la sfera sessuale e riproduttiva, peraltro già fortemente compromesse dalla lesione neurologica di per sé, quali le conseguenze per la salute generale di una così marcata e prolungata carenza androgenica per questi individui? Analizzando una casistica di uomini con lesione midollare da più di 12 mesi, con un’età compresa tra i 20 e gli 80 anni, reclutati mediante un programma di riabilitazione psico-motoria, abbiamo indagato i correlati clinici di tale carenza androgenica biochimica nell’uomo con lesione midollare e le possibili implicazioni prognostiche a medio e lungo termine sulla salute ed il benessere generale di tale popolazione. I nostri dati indicavano come bassi livelli di testosterone totale e libero calcolato erano significativamente associati a bassi livelli di 25-idrossi-vitamina D, marcatore quest’ultimo di una scarsa condizione di salute generale. Inoltre, abbiamo dimostrato come il venir meno dell’asse ipotalamo-ipofisi-testicolo, renda in questi soggetti molto evidente l’asse testicolo-osso, attraverso la relazione tra livelli serici di androgeni e di osteocalcina. Infatti, bassi livelli di oesteocalcina rappresentano un determinante predittivo ed indipendente di carenza androgenica in uomini con lesione midollare cronica. Ridotti livelli di testosterone e disfunzione erettile sono i principali determinanti di una scarsa soddisfazione della propria vita, a sottolineare che il percorso riabilitativo e di re-inserimento sociale deve tenere in considerazione anche gli aspetti andrologici. Infine abbiamo portato all’evidenza come i livelli circolanti di androgeni siano i principali determinanti del volume prostatico, indipendentemente dalla lesione midollare. Ciò spiegherebbe la bassa incidenza di cancro della prostata in uomini con mielolesione cronica, da noi dimostrata in precedenti studi. In conclusione la carenza androgenica in uomini con lesione midollare cronica rappresenta un marcatore di scarso benessere generale e dovrebbe essere tenuta in considerazione per selezionare soggetti più fragili che richiedono un maggior impegno in termini di cure ricevute.

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Clusa, Ferrand Marcel. "Population structure of Caretta caretta in the Mediterranean Sea: from nesting beaches to foraging grounds." Doctoral thesis, Universitat de Barcelona, 2014. http://hdl.handle.net/10803/133026.

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With more than 40% of the world’s population living in coastal areas, oceans have become an indispensable resource for humankind but many coastal and marine regions are suffering from multiple anthropogenic threats. Pollution, coastal tourism, agricultural practices and development of ports threaten marine species worldwide and have caused the decline of many species, some of them currently on the verge of extinction. Bycatch, the unintentional catching of non-targeted species during fishing operations has been described as one of the most important threats causing the decline of many species, especially of large marine vertebrates: sharks, sea turtles, birds and marine mammals. This is because large marine vertebrates are the most vulnerable group to bycatch due to their life-cycle characteristics, presenting a long lifespan, late age at maturity and low reproductive output. However, conservation needs for marine megafauna are particularly difficult to assess as these species usually occur in remote oceanic habitats, are distributed across entire oceans and often have complex life cycles involving migrations that cover thousands of kilometres. Thus, because sea turtle life stages may occur in different areas, a detailed knowledge on the life cycle, distribution and habitat use of these species is highly relevant as populations might face different anthropogenic impacts depending on the areas used. Accordingly, these questions have been addressed for the loggerhead turtle (Caretta caretta) in this thesis through different approaches such as population genetics, stable isotope analysis, growth models and fisheries impact assessments. The results presented in this thesis have revealed deeper structuring in nesting and foraging grounds for loggerhead turtles than previously thought. An earlier colonisation of the Mediterranean has been discovered, fine-scale rookery contributions to Mediterranean foraging grounds have been unveiled, the habitat use of nesting females has been discovered and new management units have been described within the Mediterranean Sea. The effects that foraging ground use have on loggerheads biology has also been approached showing that individual patterns of habitat use may have a remarkable effect on fitness (clutch size) and growth rates. This, in turn, may be driven by surface water circulation patterns of the basin and the trajectory followed by juvenile turtles during their developmental migration. Finally, this thesis has highlighted the importance of regional studies to understand the consequences of fisheries bycatch as the actual impact will depend on the origin of the turtles incidentally caught.
Amb més del 40% de la població mundial vivint a zones costaneres, els oceans han esdevingut una font indispensable de recursos i, com a conseqüència, la biodiversitat marina està altament amenaçada no només per l’explotació directa sinó també per factors antropogènics secundaris. Una de les causes més rellevants que estan empenyent a la desaparició de diverses espècies marines és la pesca i les captures accidentals associades a aquesta. La megafauna marina (taurons, tortugues marines, aus marines i mamífers marins) és especialment vulnerable a aquesta captura accidental degut a la maduració sexual en edats avançades, la presència d’un cicle vital de llarga durada i el baix rendiment reproductiu, entre altres, de les seves espècies. Per tal de poder aplicar plans de gestió per a la seva conservació, però, és essencial conèixer-ne el seu cicle vital, la distribució i els usos de l’hàbitat per entendre quines són les possibles amenaces que afecten les diferents poblacions i a on es localitzen. En aquesta tesi aquests factors són estudiats en la tortuga babaua (Caretta caretta) a través de la genètica de poblacions, anàlisis d’isòtops estables i models de creixement. Els resultats presentats demostren una estructuració poblacional en zones de nidificació i alimentació més forta del què es creia fins al moment per a la tortuga babaua. S’ha datat una colonització plistocènica del mar Mediterrani, s’han estimat les contribucions de cada zona de nidificació a diferents zones d’alimentació mediterrànies, s’han analitzat els usos de l’habitat de diferents poblacions i noves unitats de gestió han estat definides. També s’ha analitzat l’efecte dels usos de l’habitat sobre la biologia de la tortuga babaua i diferències en les taxes de creixement i mides de posta s’han detectat entre individus alimentant-se en zones diferents. Aquest fet, a la vegada, s’ha vist que podria estar influenciat amb els patrons de circulació d’aigua de la conca i la trajectòria seguida pels nounats i juvenils durant la seva migració primerenca. Finalment, aquesta tesi ha remarcat la importància de realitzar estudis a escala regional per entendre les conseqüències de la captura accidental ja que aquestes dependran de l’origen de les tortugues capturades.

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Tuttle, Jacob A. "Loggerhead sea turtle (Caretta caretta) nesting on a Georgia barrier island effects of nest relocation /." Connect to this title online, 2007. http://www.georgiasouthern.edu/etd/archive/fall2007/jacob_a_tuttle/tuttle_jacob_a_200708_ms.pdf.

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19

Reid, Karen A. "Incubation conditions of the loggerhead sea turtle Caretta caretta in kyparissia Bay, western Peloponnesus, Greece." Thesis, University of Aberdeen, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.425039.

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The primary aims of this three year study were to investigate the incubation environment of Caretta caretta embryos, and how this related to clutch survival and hatchling phenotype. Incubation temperature (mean 30.4 °C, n=33 nests) was significantly related to laying date and female choice of nest site. Nests laid early or late in the season, or further down the beach were more likely to attain temperatures below the pivotal for sex determination. Overall, a female biased sex ration was estimated. Low temperatures at the start of incubation and deeper nests were associated with higher early embryonic mortality. Older embryonic death increased due to seawater inundation and shallower nest depth. Post-hatching mortality increased with higher temperatures in the egg chamber at the end of incubation. Hatchling body sizes were not significantly influenced by any of the variables considered. Rates of oxygen consumption and carbon dioxide production in eggs artificially incubated at 27.5, 29.9, and 31.8 °C, increased during the second half of incubation, reaching greater maxima at higher incubation temperatures, then declining towards hatching. Respirometry quotients indicated temporal changes in substrate utilisation, with a shift from carbohydrate, to protein, and finally fat oxidation. Carbon dioxide concentrations increased then reached asymptote in natural nests. Analysis of the ratio of carbon-13 to carbon-12 (determined by mass spectrometry) revealed that the increase in nest CO₂ concentration was attributable to embryonic metabolism. Nest CO₂ concentration increased with the number of developing embryos to a maximum of 1.8 %, but did not have a negative effect on hatchling success, suggesting substrate diffusion capacity does not constrain clutch mass.

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20

Henaghan, Christopher. "Incubation Temperature Effects on Loggerhead (Caretta caretta) and Green (Chelonia mydas) Sea Turtle Hatchling Vigor." Thesis, Florida Atlantic University, 2019. http://pqdtopen.proquest.com/#viewpdf?dispub=13419688.

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Climate change has the potential to expose sea turtle nests to higher temperatures, which may negatively impact sea turtle hatchling vigor. In this study, loggerhead and green hatchlings were sampled from the Boca Raton, Florida beach and via lab incubation, and hatchling vigor was determined. Elevated nest temperatures decreased loggerhead and green turtle hatchling performance and corticosterone levels, with the most significant effects found in hatchlings exposed to maximum incubation temperatures above 35 °C during late development. Lab-incubated loggerhead post-hatchling corticosterone levels and growth rates were also determined. The differences seen in corticosterone levels with overall nest incubation temperatures, mean temperatures during early, middle or late stages of development, and its negative correlation with hatchling performance improves our understanding of the underlying physiological mechanisms linking elevated incubation temperatures and sub-lethal physiological effects that may significantly impact hatchling survival, a critical step for sea turtle conservation in south Florida and elsewhere.

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21

Delgado, Cláudia Maria Neves. "Gonad development and hormone titres in Loggerhead Sea Turtles (Caretta caretta) in the NE Atlantic." Doctoral thesis, Universidade da Madeira, 2008. http://hdl.handle.net/10400.13/32.

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The study proposed to describe sexual development in pelagic stage loggerhead sea turtles Caretta caretta and compare this to hatchlings and adults. It is meant as an ontogenic approach, in order to understand reproductive development and population composition and their dynamics in the pelagic environment. The study focused on the pelagic loggerheads that are found in the waters offshore Madeira Island (Portugal) in the North-eastern Atlantic and use it as a developmental habitat. The innovating character of this work relied on the lack of any description regarding the gonad ontogenesis and reproductive development for the pelagic stage in any of the 7 existing sea turtle species, all of them in danger of extinction. Three methods were used to diagnose the sex of each juvenile individual and asses the level of reproductive development: (1) laparoscopy, (2) gonad biopsy and (3) the assessment of two sex steroids circulating levels, namely testosterone and estradiol. In order to cover all life stages and compare data obtained for the juvenile stage, hatchlings and nesting female adults were sampled at the nearest nesting rookery at Boa Vista Island in the Cape Verde Archipelago. Gonads from dead hatchlings were collected for gonad histology and blood was collected from nesting females for sex steroids assessment. Laparoscopies revealed to be a valid sexing method for the juvenile stage, since gonads are morphologically differentiated at these size classes. Moreover, laparoscopy was validated using gonad histology. Gonad histology of juveniles showed that gonads are already completely differentiated into ovaries or testes at the size classes examined, but development seems to be quiescent. Males present already developed seminiferous tubules with spermatogonia lining the interior of the seminiferous tubule. Female gonads present oocytes at different development stages, but only oocytes up to stage III were observed. The maximum oocyte diameter in each individual correlated with body size, suggesting that reproductive development is an on-going process in juvenile females. The circulating levels of both testosterone and estradiol in juveniles of both sexes were very low and consistently lower than the ones observed in the nesting females from Boa Vista Island. No bimodal distribution was found for any of the sex steroids analysed and thus circulating hormone levels were not a reliable tool for sexing juvenile individuals with a non-invasive technique. The ratio testosterone:estradiol did not show a bimodal distribution either. The levels of testosterone correlated with sea surface temperature. The fact that temperatures observed during this study were below 24ºC might have hindered a differential testosterone pattern between juvenile males and females. Sex ratios for this population were generated according to laparoscopy results and compared among years and size classes. An overall sex ratio of 2 females for each male was found, but they varied among size classes but not among years. Possible causes for the sex ratios observed are discussed. This study is a contribution to our knowledge on the pelagic stage of loggerhead turtles, namely on the population structure regarding sex ratio, which is a vital tool for implementing conservation strategies.
Orientadores: Thomas Dellinger and Adelino Canário

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22

Hatase, Hideo. "Studies on migration, dynamics, and genetic variation in Japanese loggerhead turtle (Caretta caretta) nesting populations." Kyoto University, 2002. http://hdl.handle.net/2433/149503.

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Kyoto University (京都大学)
0048
新制・課程博士
博士(農学)
甲第9778号
農博第1290号
新制||農||852(附属図書館)
学位論文||H14||N3709(農学部図書室)
UT51-2002-M156
京都大学大学院農学研究科応用生物科学専攻
(主査)教授坂本亘, 教授田中克, 教授林勇夫
学位規則第4条第1項該当

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23

Nelson, David A. "Subadult loggerhead sea turtle (Caretta caretta) behavior in St. Mary's entrance channel, Georgia, United States." W&M ScholarWorks, 1996. https://scholarworks.wm.edu/etd/1539616790.

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A study of channel utilization and behavior of subadult loggerhead turtles was conducted in the St. Mary's River entrance channel area, Georgia. A total of 38 loggerheads were captured by trawling and instrumented with radio and depth sensitive sonic tags from April to November 1993. Turtles were monitored for 6 to 36 hours continuously for approximately 30 days in the spring (13), summer (13), and fall (14). On a daily basis turtles generally confined their diving activity to one location for one to twelve hours in 10 to 20 m water depths then moved 1 to 5 kilometers to a new location. Overall the turtles spent only a small percent of time in/near the channel. Duration of diving variables varied widely among and between individuals. The loggerhead turtles spent a small percent of time and short durations at the sea surface and large percent of time and long durations associated with the sea floor. A turtle would typically surface 1-4 times per hour. In general, bottom durations, submergence durations, and dive cycle durations were longer at night than during the day, with twilight durations intermediate between the two. Turtles surfaced more frequently during the day than at night. No day/night pattern was observed for surface duration, descent duration, ascent duration, ascent rate, and descent rate. Ascent duration was longer and ascent rate slower than descent duration and descent rate, respectively. Mean surface durations were greater in the spring than summer and fall. Surface/submergence frequency was less in the fall than in spring and summer. Bottom durations, submergence durations, and dive cycle durations were longer in the fall than in the spring or summer. Surface durations, descent durations, ascent durations, ascent rates, and descent rates did not differ seasonally. In the spring, summer, and fall loggerhead turtles spent most of their time on the sea floor outside the channel, dove more actively during the day than at night, and remained in one location for up to 12 hours at 10-20 m water depths.

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Miller, Dawn M. "Beach Crawl Width as a Predictive Indicator of Carapace Length in Loggerhead Sea Turtles (Caretta caretta)." NSUWorks, 2002. http://nsuworks.nova.edu/occ_stuetd/20.

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Carapace lengths and widths of nesting loggerhead sea turtles (Caretta caretta) were measured at Pompano Beach and Fort Lauderdale, Florida to determine if plastron and/or track crawl widths were predictive of carapace size. Straight and curved carapace measurements were taken. Plastron and track crawl width were measured at four points on each crawl: 1) emerging at the tide line; 2) mid-way to the nest; 3) mid-way returning to the surf; and 4) at the tide line returning to the surf. All four measurements were significantly different from each other (P < 0.005) along each crawl. Crawl width was the most variable factor in all comparisons. Maximum straight carapace length correlated with emergent track crawl width at the tide mark (r = 0.8464, P < 0.001), indicating that track width was predictive of straight carapace length (+/- 3.95 cm standard error of estimate). Clutch size correlated with notch-to-tip straight carapace length (r = 0.6635, P < 0.0005) and with emergent track crawl width measured mid-way to the nest (r = 0.5735, P < 0.005). Carapace and crawl width measurements were predictive of clutch size (+/- 21 eggs and 23 eggs standard error of estimate, respectively).

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Gilbert, Collette F. "Impact of Hurricanes on Caretta caretta Nesting Success, Hatching Success and Washout Rate in Broward County." NSUWorks, 2013. http://nsuworks.nova.edu/occ_stuetd/167.

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Hurricanes can cause considerable damage along the coastlines of the United States. There are very little data relating hurricanes and sea turtle nesting. Hurricane season (June- November) and sea turtle nesting season, for the study period, (March- September) overlap in Broward County, Florida. This paper examines the relationship between the Hurricane Impact Index (HII) and hatching success of loggerhead sea turtles (Caretta caretta) and HII and washout rate. For ten of the eleven storms studied, there was no significant relationship between HII and hatching success (percent). Tropical Storm Ophelia (2005) showed a significantly higher (p=0.0206) hatching success after the storm’s passing than before the storm’s passing. There was a significant relationship between washout rate and HII (p=0.026).

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de, Wet Anje. "Factors affecting survivorship of loggerhead (Caretta caretta) and leatherback (Dermochelys coriacea) sea turtles of South Africa." Thesis, Nelson Mandela Metropolitan University, 2012. http://hdl.handle.net/10948/d1007900.

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Loggerhead (Caretta caretta) and leatherback (Dermochelys coriacea) sea turtles as well as their eggs and hatchlings have been protected on their nesting beach in South Africa (SA) since 1963. Both nesting populations were expected to show similar trends in recovery following the application of identical protection and conservation measures. The loggerhead nesting population has responded favourably to these protection efforts. In contrast, the leatherback nesting population showed an initial increase but is currently stable. The reason for this difference in response is thought to be due to differential offshore mortality of these two species. This prompted an investigation into the different sources of sea turtle mortality in the South Western Indian Ocean (SWIO). Specific aims were to identify and quantify sources of loggerhead and leatherback mortality on nesting beaches as well as in the oceans. Reasonable survivorship at all age classes is important to ensure recruitment of new nesting individuals into sea turtle populations. Mortality of nests, eggs per nest and hatchlings were quantified over two seasons for the loggerheads and leatherbacks nesting in SA. The beach was patrolled on foot to encounter and record females emerging from the ocean and later, hatchlings from their nests. The nests were then monitored during the incubation period and excavated once hatched. The fates of 925 nests were determined during these two nesting seasons (2009/2010 and 2010/2011). The main source of loggerhead and leatherback nest destruction was predation (8.6 percent and 15.7 percent respectively) followed by nest erosion (2.2 percent and 6.3 percent respectively). Overall nest success was high but higher for loggerheads (89 percent) than for leatherbacks (78 percent). The main cause of egg mortality for both species was early developmental arrest, followed by predation by ants and ghost crabs. Hatchlings en route to the sea were almost exclusively predated by ghost crabs (4.2 percent of emerged loggerhead hatchlings and 3.2 percent of emerged leatherback hatchlings). It appears that both species benefit from the coastal conservation efforts. When sea turtles leave the nesting beach, either as hatchlings or adults, conservation and monitoring becomes more difficult and sea turtles are exposed to a multitude of threats, including anthropogenic threats. Age classes tend to be spatially separated due to different habitat and dietary requirements. The type of threat sea turtles are exposed to thus depends on the current age class. Offshore sources of mortality in the SWIO were identified and where possible loggerhead and leatherback mortality was quantified and mapped spatially. Loggerheads were mostly exposed to and had the highest mortality in the artisanal fisheries in the SWIO (> 1000 per annum), inshore trawling (ca. 41 per annum), shark nets (protective gill nets) (21.6 ± 6.7 per annum) and the pelagic longline fishery (5.0 ± 4.4 per annum). In contrast, leatherbacks with a pelagic lifestyle, were mostly exposed to pelagic longline fisheries (7.8 ± 7.8 per annum). A spatial analysis of fishing activities indicated that leatherback home ranges overlapped 41percent with pelagic longline fishing activity in the SA EEZ, whereas the overlap between pelagic longliners and loggerhead home ranges was 29 percent. The quantified sources of mortality provide some explanation for the trend in the loggerhead nesting population but not the trend in the leatherback nesting population. Hatchling survivorship to adulthood was estimated to determine the viability of the two nesting populations as well as to determine whether offshore mortality was responsible for the difference in recovery of the two populations. Loggerhead hatchling survivorship to adulthood was estimated at between 2 and 10 per 1000 hatchlings, the minimum requirement for an increasing population. The adopted sophisticated model shows that leatherbacks have a survival rate of 5 to 10 per 1 000 hatchlings. However, this suggests that the population is increasing, but the leatherback population is stable. Perhaps the age to maturity of SA leatherbacks is greater than 12 years, or fisheries-related mortality affects younger age classes than initially thought. It is therefore recommended that the turtle monitoring area is extended to include other potential nesting grounds. In addition, observer or monitoring programs for commercial as well as artisanal fisheries needs to be extended throughout the SWIO to quantify sea turtle mortality. Ultimately a comprehensive multi-regional approach is required for the conservation of these highly migratory species.

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Fuxjager, Matthew J. Lohmann Kenneth J. "Magnetic orientation and navigation behavior of loggerhead sea turtle hatchlings (Caretta caretta) during their transoceanic migration." Chapel Hill, N.C. : University of North Carolina at Chapel Hill, 2007. http://dc.lib.unc.edu/u?/etd,1052.

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Thesis (M.S.)--University of North Carolina at Chapel Hill, 2007.
Title from electronic title page (viewed Mar. 27, 2008). "... in partial fulfillment of the requirements for the degree of Master of Science in the Department of Biology Evolution, Ecology and Organismal Biology." Discipline: Biology; Department/School: Biology.

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Flynn, Lindsey Nicole. "Thermal Determinants of Nest Site Selection in Loggerhead Sea Turtles, Caretta caretta, at Casey Key, Florida." Scholar Commons, 2012. http://scholarcommons.usf.edu/etd/4323.

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Many environmental cues are thought to influence nest site selection by loggerhead sea turtles, Caretta caretta, and much debate exists over the possible influence of sand temperature. This study had two primary objectives: (1) to measure thermal differences across transects of a major nesting beach of Casey Key (28.7 N, 82.3 W), Florida and (2) to evaluate thermal pattern variation that influenced nesting patterns of adult female loggerhead sea turtles. A secondary objective of this study was to determine the efficacy of infrared thermometers to collect sand surface temperatures in the field. Temperature data were collected from 145 nest events and 8 false crawls in the 2008 and 2009 nesting seasons. Infrared thermometers and thermocouple probes were used to obtain surface temperatures from the water, waterline, beach sand, body pit attempts, nest chamber attempts, eggs, and the surface of the gular skin of the nesting female, within the crawl track created by the female and at one meter adjacent to the crawl track (from undisturbed sand). Weather influences at the time of nesting were recorded, including the presence or absence of rain, wind, or clouds. Beach slope was measured using an angle locator. Temperature data from the infrared thermometer and the thermocouple probe were highly correlated, indicating that an infrared thermometer is an effective measurement tool on a nesting beach. In 2008, there was a significant difference between temperatures collected within the crawl tracks of false crawl events and nest events, indicating a potential for females to use thermal cues in choosing whether to false crawl or nest. In both nesting seasons, the sand temperature in the body pit and the surface of the gular skin of the nesting female were nearly identical, suggesting females may locate a suitable nest site using their skin temperature. Data collected at other loggerhead rookeries in the United States and Australia yielded similar results, however, variability in the use of temperature may arise seasonally, and according to different nesting environments. Rain, wind and cloud cover significantly thermally altered several locations on Casey Key, but it remains unclear if these weather events significant affect turtle nesting behavior. Additionally, crawl distance and beach slope were significantly, positively correlated. Gravid females most likely use multiple environmental cues to select a nest site. Assimilating information from multiple sources allows for the highest degree of adaptability, and future studies should consider implications for climate change and beach renourishment projects.

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Bartol, Soraya M. "Morphological, electrophysiological and behavioral investigation of visual acuity of the juvenile loggerhead sea turtle (Caretta caretta)." W&M ScholarWorks, 1999. https://scholarworks.wm.edu/etd/1539616563.

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A majority of the research on sea turtle vision focuses on the turtle's ability to perceive shapes, colors and brightness cues on land. However, aerial vision is a minor component of the visual ability of sea turtles, potentially used only when surfacing to breathe, while basking, and during female reproductive activities. For my doctoral dissertation, I examined the aquatic visual acuity of juvenile loggerhead sea turtles (Caretta caretta) by investigating the morphology of the eye, the electrophysiology of response to stimuli, and the behavior to specific stimuli. For the morphological experiments, eyes were obtained from loggerheads, euthanized due to injury, and histological techniques were used to identify both cell types as well as regionization of cell densities. For the collection of electrophysiological responses from healthy juvenile loggerheads, testing was performed using a water-filled goggle and subdermal platinum electrodes implanted over the optic nerve and contralateral optic tectum. Stimuli were flickering black and white gratings. Visual evoked potentials (VEPs) were collected using an averaging computer and thresholds were measured from the recordings. Finally, for the psychophysical study, loggerheads were trained, in a 500-gallon tank, to discriminate between a vertical grating and a 50% gray panel using positive reinforcement. Thresholds were then recorded from incrementally smaller gratings. These data, from the three techniques used in this study, suggest that vision does play an integral role in the juvenile loggerhead's perception of its surroundings. Higher concentrations of cone photoreceptors and ganglion cells were found in the dorsal region of the eye, indicating an area centralis. Furthermore, the cone and rod photoreceptor densities throughout the eye suggest that this animal is capable of both visual acuity and sensitivity. Acuity threshold, measured from the VEP recordings, was approximately 5.4 minutes of arc for all turtles tested. Moreover, the psychophysical experiment measured an acuity threshold of 12.9 minutes of arc. The regionalization of acuity in the dorsal hemisphere of the eyes as well as the acuity threshold levels recorded for juvenile loggerhead sea turtle suggests that loggerheads are using vision for foraging, predator avoidance, territory selection and defense, and other basic behaviors in their aquatic surroundings.

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Wingfield, Dana K. "On the formation of a conservation hotspot for juvenile North Pacific loggerhead sea turtles (Caretta caretta) /." Diss., Digital Dissertations Database. Restricted to UC campuses, 2009. http://uclibs.org/PID/11984.

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Seney, Erin E. "Historical Diet Analysis of Loggerhead (Caretta caretta) and Kemp's Ridley (Lepidochelys kempi) Sea Turtles in Virginia." W&M ScholarWorks, 2003. http://www.vims.edu/library/Theses/Seney03.pdf.

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Petitet, Roberta. "Idade e crescimento da tartaruga cabeçuda (Caretta caretta) no litoral sul do Rio Grande do Sul." reponame:Repositório Institucional da FURG, 2010. http://repositorio.furg.br/handle/1/4275.

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Dissertação(mestrado) - Universidade Federal do Rio Grande, Programa de Pós–Graduação em Oceanografia Biológica, Instituto de Oceanografia, 2010.
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A espécie de tartaruga marinha Caretta caretta (tartaruga-cabeçuda) utiliza a costa brasileira para desenvolvimento e reprodução, suas praias de desova estão situadas nos estados da Bahia e Espírito Santo. A maioria dos estudos sobre a tartaruga-cabeçuda no Brasil lidam com fêmeas adultas e os estágios de juvenis e sub-adultos são pouco conhecidos. O presente estudo faz uma estimativa da idade de tartarugas-cabeçudas através da técnica de esqueletocronologia por análises do úmero provenientes de ambos os estágios, nerítico e oceânico. E ajusta um modelo de crescimento para a população dessa espécie do Atlântico Sul Ocidental. Baseado na validação de que uma linha de crescimento corresponde a um ano, os números de linhas presentes no úmero correspondem a idade do animal. Para tartarugas de tamanho maior, foi aplicado o fator de correção para o cálculo de linhas perdidas devido à reabsorção óssea e perda das primeiras linhas de crescimento. Esse fator de correção foi baseado em dois modelos, o primeiro denominado “simples” que não incorpora a variação na deposição de linhas de crescimento no animal e entre animais, já o segundo modelo, denominado “hierárquico” faz essa incorporação. O modelo hierárquico obteve melhor ajuste aos dados de tamanho (CCC – comprimento curvilíneo da carapaça) e diâmetro do úmero, provavelmente devido a experiências desses répteis em ambientes com condições estocásticas, portanto alguns indivíduos podem crescer mais do que outros. A estimativa da duração do estágio oceânico foi de 8 a 19 anos (com média de 11,5) e a idade de maturação de 25,7 a 39,2 anos (com média de 31,2 anos). O modelo de crescimento de Schnute se ajustou bem aos dados de tamanho (CCC) e idade, devido sua versatilidade em forma e não requerimento de dados de tamanho de animais neonatais e de adultos próximos ao tamanho assintótico. Entretanto, a “curva” de Schnute foi bastante similar a uma reta, portanto foi ajustada uma regressão linear que obteve um melhor ajuste aos dados, que por sua vez, é composto por uma “janela de idade” do ciclo de vida das tartarugas marinhas. A “Hipótese de proporcionalidade corporal” foi aplicada para o cálculo das taxas de crescimento. As taxas de crescimento das tartarugas-cabeçudas neríticas foram similares as reportadas para tartarugas-cabeçudas do Atlântico Norte, porém menores do que as tartarugas oceânicas do Atlântico Sul. Sugerindo que as condições ambientais locais podem influenciar na taxa de crescimento da tartaruga marinha, como também, a energia gasta durante migrações, alocação de energia e origem genética.
The juvenile and sub-adult stages of loggerhead sea turtles (Caretta caretta) are poorly studied in Brazil. We present age estimates and a growth model for loggerhead sea turtles in the South Atlantic Ocean obtained through skeletochronological analysis of humeri obtained from both neritic and oceanic stage individuals. Since it was validated that each increment growth corresponds to one year for loggerhead sea turtle, the number of lines of arrested growth (LAGs) was taken as the age estimated. For larger turtles a correction factor was applied to solve for lost LAGs. This correction factor was based on two models, the first denoted “naïve” makes no distinction between inter- and intra-individual variability and the second denoted “hierarchical”, takes this distinction into account. The hierarchical model had the best fit to the data set, probably because these reptiles experience stochastic conditions through their life cycle, so that some individuals may grow more than others. The estimated ages indicate that the duration of the pelagic stage is 8 to19 years (average 11.5 years) and the age at maturation ranges from 25.7 to 39.2 years (average 31.2 years). Schnute‟s growth model was fit to age-at-length data, due to its versatility in shape and no requirement of size data for hatchlings up to individuals at old ages with near asymptotic size. However, since the shape of Schnute`s curve was almost linear for the age-window comprising our data, a linear regression ultimately yielded a slightly better fit. The “Body Proportional Hypothesis” was incorporated in the calculation of growth rates. Growth rates from neritic stage South Atlantic loggerheads were similar to those reported for neritic loggerhead sea turtles from the North Atlantic, but lower than for oceanic loggerheads from South Atlantic. This finding suggests that local environmental conditions influence turtle‟s growth rates, as well as, the energy expenditure during migrations, energy allocation and genetic origin.

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Ulrich, Marie. "Feeding Behaviour in Loggerhead Sea Turtles (Caretta caretta) : Collection of Movement Data Representative of Feeding Events." Thesis, Linköpings universitet, Institutionen för fysik, kemi och biologi, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-158002.

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With the different threats sea turtles are currently facing, such as habitat reduction and pollution, increase of fishing and harvesting of aquatic resources by Humans, or invasive species, it is important to learn as much as possible about their biology and behaviour in order to ensure the success of conservation programs. In this study, loggerhead sea turtles (Caretta caretta) feeding behaviour duration as well as energy expenditure approximation during a feeding event were tested and compared using two different types of food: green shore crabs (Carcinus maenas) or Japanese clam (Ruditapes phillipinarum) or Venus clams (Chamelea gallina). The data show that the turtles took longer to approach the crabs but took more time to eat the clams. However, comparison of energy expenditure values for the feeding phase showed no significant differences. The turtles were observed to eat the clams’ shell as well as their meat. These shells are rich in calcium, which is one possible explanation for this behaviour. This study shows that data loggers represent a viable tool for studying the behaviours of marine animals.

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GAROFALO, LUISA. "The Genetics of the loggerhead turtle (Caretta caretta) in Italy: from scientific data to public knowledge." Doctoral thesis, Università degli Studi di Roma "Tor Vergata", 2010. http://hdl.handle.net/2108/1347.

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In questa tesi sono stati affrontati con metodologie genetiche diversi aspetti riguardanti la biologia riproduttiva, la filogeografia e il valore conservazionistico della tartaruga marina Caretta caretta. Il campionamento, strettamente non invasivo, ha coperto diverse aree italiane e maltesi e tutti gli stadi vitali della specie. La caratterizzazione genetica della principale colonia di nidificazione italiana (Calabria ionica) ha individuato marcatori nell’mtDNA specifici di questa popolazione. La diversità genetica riscontrata di questa colonia ha portato inoltre a riconsiderare la filogeografia complessiva di questa specie nel Mediterraneo. Il DNA moderno e quello antico, analizzato per marcatori mitocondriali e nucleari, ha chiarito la composizione degli aggregati costieri che frequentano le acque italiane e maltesi. Queste informazioni possono risultare utili anche per la formulazione di piani di gestione. In ultimo, le nuove possibilità aperte dagli studi genetici sono state divulgate tramite un DVD destinato al grande pubblico, che illustra il prezioso lavoro di diverse Istituzioni scientifiche e autorità pubbliche nel recupero delle tartarughe spiaggiate e nello studio e salvaguardia di specie a rischio di estinzione.
Genetic methodologies were used in this thesis to increase the knowledge on the reproductive biology, the phylogeography and the conservation value of the sea turtle Caretta caretta. Non-invasive sampling covered different Italian and Maltese areas and all the life stages of this species. The genetic characterization of the main Italian nesting colony (Ionian Calabria) identified specific mtDNA markers of this population. Genetic diversity found in this colony led also to reconsider the phylogeography of this species in the entire Mediterranean. Modern and aDNA, analyzed for both mitochondrial and nuclear markers, shed light on the composition of loggerhead coastal aggregates in Italian and Maltese waters, useful as well for management plans. Finally, the new possibilities opened by genetic studies were disseminated through a DVD, addressed to a broad audience. It explains the invaluable work of several scientific Institutions and public authorities in the rescue of stranded sea turtle and in the study and protection of endandered species.

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Davidsson, Joanna. "Mediedrevet kring Carema Care : En analys av Carema Cares kriskommunikation under mediedrevet 2011." Thesis, Högskolan för lärande och kommunikation, Högskolan i Jönköping, HLK, Medie- och kommunikationsvetenskap, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:hj:diva-35035.

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Carema Care (numera Vardaga) är ett privat ägt vårdföretag med verksamhet inom äldreomsorgen. Under hösten och vintern 2011 utsattes företaget för en intensiv mediebevakning där de anklagades för besparingar och vanvård. I denna uppsats undersöks Carema Cares externa kriskommunikation under mediedrevet. Kriskommunikationen analyseras utifrån situational crisis communication theory. Teorin beskriver vilka försvarsstrategier som ett företag kan och bör använda för att rädda sitt anseende. Teorin gör gällande att den viktigaste faktorn vid val av försvarsstrategi bör vara typ av kris som uppstått. Studien har utgått ifrån en kvalitativ textanalys med systematiserande frågeställningar och klassificering som tillvägagångssätt. Först analyserades nio nyhetsartiklar för att försöka fastställa vilken typ av kris som ägt rum. Därefter studerades Carema Cares pressmeddelanden för att identifiera vilka försvarsstrategier som Carema Care använt sig av och om dessa överensstämmer med vad som föreskrivs inom situational crisis communication theory. Resultatet visar på att Carema Care inte i något pressmeddelande använt sig av de försvarsstrategier som föreskrivs i situational crisis communication theory.
Carema Care (now by the name Vardaga) is a privately owned company within the field of elder care. During the autumn and winter of 2011, the company was the focal point of an intense media reporting. The company was accused of budget cuts and neglected care. This thesis investigates the external crisis communication from Carema Care during the intense media reporting. The crisis communication is analyzed using situational crisis communication theory. The theory describes which crisis response strategies that a company can and shall use when faced with a crisis in order to restore its image. The theory claims that the most important factor when choosing crisis response strategy is what type of crisis that has occurred. The investigation was carried out using qualitative text analysis, more specifically the method systematic questions and classification was used. In the first step, nine news articles were analyzed in order to determine what type of crisis that had occurred. In the second step, the press releases following each news article were analyzed in order to determine what response strategy that had been used and how it compared to what the theory recommended. The study shows that Carema Care did not use the response strategy recommended from situational crisis communication theory in any of its press releases.

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Ferri, Fabrizio. "Misura di mitigazione degli effetti della carenza idrica nei sistemi acquedottistici." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2008. http://amslaurea.unibo.it/176/.

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CORNO, ANNA ROSA. "CARENZA CONGENITA DI ANTITROMBINA E DIAGNOSI DI LABORTORIO: QUALE TEST FUNZIONALE?" Doctoral thesis, Università degli Studi di Milano, 2014. http://hdl.handle.net/2434/233996.

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Introduzione - La carenza congenita di Antitrombina (AT), che espone a rischio trombotico di tipo prevalentemente venoso, viene classificata in tipo I (difetto quantitativo) o tipo II (difetto qualitativo). I difetti qualitativi possono interessare il sito reattivo (Reactive Site, RS) o il sito di legame dell’AT con l’eparina (Heparin Binding Site, HBS), oppure possono avere effetto pleiotropico (PE). I test di screening, che misurano la capacità dell’AT, presente nel plasma, di neutralizzare la trombina (attività anti-IIa) o il Fattore Xa (attività anti-Xa) in presenza di eparina, sono in grado di evidenziare la maggior parte dei difetti dell’AT; tuttavia, sono stati osservati risultati discrepanti (valore normale vs. valore patologico) con i due differenti metodi. Scopo della tesi è quello di valutare la concordanza tra un test AT anti-Xa e un test AT anti-IIa e di valutare la relativa capacità di individuare le carenze di AT. Materiali e Metodi – La popolazione in studio è costituita dal gruppo “routine e trombofilici” (493 soggetti con prescrizione del test AT) e dal gruppo “carenti noti” (23 soggetti con carenza nota di AT e 18 familiari). I dosaggi dell’attività dell’AT sono stati effettuati con i metodi AT anti-Xa (HemosIL, Instrumentation Laboratory) e AT anti-IIa (home-made). Una popolazione di controllo (n= 100) è stata utilizzata per definire i relativi intervalli di riferimento. In 21 soggetti con carenza di AT è stata effettuata la ricerca di mutazioni nel gene SERPINC1 (Universitair Ziekenhuis di Bruxelles). Risultati – I risultati di AT% ottenuti con i due metodi sono altamente correlati (rho di Spearman >0.70); tuttavia, sono stati riscontrati 8 dati discordanti (3 nel gruppo “routine e trombofilici”, 5 nel gruppo “carenti noti”). L’analisi genetica ha identificato la presenza di mutazioni nel gene SERPINC1 in 18/21 soggetti studiati, 5 dei quali con valori di attività AT discordanti. Infatti, valori normali di AT anti-Xa si sono ottenuti per il difetto Cambridge II (II RS), mentre il test AT anti-IIa ha fornito valori normali per un difetto HBS. Valori di AT patologici concordi sono stati ottenuti per 5 carenze di tipo I, mentre si sono ottenuti risultati di AT normali con entrambi i metodi per altre 2 carenze HBS. Nella popolazione indagata la sensibilità del test AT anti-Xa è 61.1%, quella del test AT anti-IIa è 55.6%. Se si considerano entrambi i test la sensibilità diventa 72.2%. Se si utilizza in aggiunta anche il rapporto tra l’attività AT anti-IIa e l’attività anti-Xa, la sensibilità aumenta a 88.9%. Conclusioni – I metodi funzionali attualmente a disposizione per il dosaggio dell’AT non sono in grado di individuare tutti i tipi di difetti molecolari dell’AT. L’utilizzo combinato di un test anti-Xa e di un test anti-IIa e del rapporto AT anti-IIa/AT anti-Xa potrebbe aumentare la capacità diagnostica dei dosaggi. I risultati dei test di laboratorio vanno comunque considerati alla luce della storia clinica personale e familiare del soggetto.
Introduction – Antithrombin (AT) deficiency, associated with an increased risk for venous thrombosis, is classified into type I (quantitative defect) and type II (qualitative defect). Qualitative defects may affect the reactive site (RS), the heparin binding site (HBS) of AT, or they may have a pleiotropic effect (PE). Screening tests, which measure the ability of AT, in the presence of heparin, to inhibits either thrombin (anti-IIa activity) or FXa (anti-Xa activity), are able to detect most AT deficiencies; however, few cases of discrepancies have been described (i.e. normal vs. pathological value) with the two different methods. Aim of the study was the evaluation of agreement between an anti-Xa assay and an anti-IIa assay for AT, and the evaluation of their ability in detecting AT defects. Materials and Methods – The study population consisted of the “routine and thrombophilic” group (493 patients for which AT test was required) and the “historical deficiencies” group (23 subjects with known AT deficiency and 18 relatives). Anti-Xa HemosIL Antithrombin kit (from Instrumentation Laboratory) and a home-made anti-IIa method were used to measure AT activities. A control group (n= 100) was used to determine AT reference ranges. SERPINC1 gene analysis was carried out for 21 patients (Universitair Ziekenhuis in Bruxelles). Results – The results provided by the two methods showed a high correlation (Spearman rho>0.70); however, 8 discrepant results were observed (3 in the “routine and thrombophilia” group and 5 in the “historical deficiencies” group). Gene analysis confirmed the presence of a molecular defect in 18/21 subjects, 5 of which had also descrepant AT results. In fact, normal anti-Xa AT values were obtained for Cambridge II defect (RS), whereas anti-IIa test provided normal values for a HBS defect. Both methods provided pathological AT values for 5 type I deficiencies but normal AT values for other 2 HBS defects. In the study population AT anti-Xa and AT anti-IIa sensitivity was 61.1% and 55.6%, respectively; when both tests were used, sensitivity increased to 72.2%. When the ratio between AT anti-IIa and AT anti-Xa was added, sensitivity increased to 88.9%. Conclusions – Currently avaible screening tests are not able to detect all molecular defects. However, when anti-Xa assay is carried out together with anti-IIa method, and the ratio between the results provided by both is considered, the diagnostic power is increased. Anyway, laboratory test results should be considered together with personal and familiar clinical history of the single subject under evaluation.

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Guzman, Alejandra. "Bite performance and feeding kinematics in loggerhead turtles (Caretta caretta) within the context of longline fishery interactions." [College Station, Tex. : Texas A&M University, 2008. http://hdl.handle.net/1969.1/ETD-TAMU-2844.

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Zielinski, Michele. "False Crawls of Loggerhead Turtles (Caretta caretta): Causation and Impacts on Nesting Success in Broward County, Florida." NSUWorks, 2014. http://nsuworks.nova.edu/occ_stuetd/142.

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The greatest sea turtle nesting in the United States occurs in Florida, which accounts for more than 85% (Shoop et al, 1985). Five species of sea turtle have been documented nesting in Florida, including the loggerhead (Caretta caretta), green (Chelonia mydas), leatherback (Dermochelys coriacea), kemp’s ridley (Lepidochelys kempi), and hawksbill (Eretmochelys imbricata) sea turtles. In southeast Florida, the loggerhead is the most common nester. The distribution of loggerhead nest numbers laid in 85 survey zones stretching along Broward County beaches between the Palm Beach County line and the Port Everglades Inlet have been highly correlated for aver a decade (P<<0.001). This study attempted to understand the reasons for this distribution by evaluating the distributions of false crawls and nesting success rates from 2000 through 2010. The nest and false crawl patterns in the 85 beach zones were all highly correlated for all 11 years (P < 0.01). These strong positive correlations indicate that these turtles receive preemergence cues, such as visual or depth profile, to primarily determine their emergence locations. However, weaker correlations between yearly nesting and nesting success patterns indicate that on-beach (post-emergence) cues also play a less important role in nest site selection.

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Leonard, Ozan Corey R. "Evaluating the Effects of Beach Nourishment on Loggerhead Sea Turtle (Caretta caretta) Nesting In Pinellas County, Florida." Scholar Commons, 2011. http://scholarcommons.usf.edu/etd/3204.

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The health of Florida's beaches are vital to the survival of loggerhead sea turtles (Caretta caretta), as nearly half of the world's loggerheads nest on the states beaches. Many of the beaches utilized by the turtles have undergone nourishment projects in hopes of combating erosion of the shoreline, protecting beachfront property, and creating more suitable beaches for tourism. Although it is argued that beach nourishment benefits sea turtles by providing more nesting habitat, the effects of the Pinellas County nourishment projects on loggerhead nesting are unknown. Beach nourishment can alter the compaction, moisture content, and temperature of the sand, all of which are variables that can affect nest site selection and the proper development of eggs. This research has four objectives: (1) to create a GIS dataset using historic loggerhead sea turtle data collected at the individual nest level along the West coast of Florida, (2) to examine the densities of loggerhead nests, the densities of false crawls (i.e. unsuccessful nesting attempts), and the nest-to-false crawl ratio on natural and nourished beaches for the 2006-2010 nesting seasons; (3) to determine the effects of beach nourishment projects on the hatchling success rates and emergence success rates; and (4) to determine areas preferred or avoided by turtles for nesting. The study found that nesting and false crawl densities significantly differed between natural and nourished beaches during three of the five nesting seasons. Nesting densities increased directly following nourishment and false crawl densities were higher in nourishment areas during every nesting season. False crawl densities were higher than statistically expected on nourished beaches and lower than expected on natural beaches. No significant differences were found between hatchling and emergence success rates between natural and nourished beaches. However, when the rates were analyzed by nesting season, the average hatching and emergence success rates were always lower on nourished beaches than on natural beaches. A hotspot analysis on nests and false crawls revealed that turtles preferred natural beaches that border nourished areas for nesting while false crawls were more evenly distributed through the study area. Although this study documents the negative effects of beach nourishment on loggerhead sea turtle nesting, nourishment projects are likely to continue because of their benefits to human populations. Further examining of the impacts that humans have on nesting and developing loggerheads will ultimately aid policy formation as we continue to manage and protect the future of the species.

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Martin, Kelly. "Underwater Hearing in the Loggerhead Turtle (Caretta caretta): A Comparison of Behavioral and Auditory Evoked Potential Audiograms." Scholar Commons, 2011. http://scholarcommons.usf.edu/etd/3233.

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Methods for collecting behavioral audiograms are often time consuming and require trained, captive subjects. It is more practical to measure hearing sensitivity using electrophysiological methods, such as auditory evoked potential (AEP) testing, in which electrodes measure action potentials in response to acoustic stimuli. These data can be collected in a matter of hours. However, results should be verified through behavioral testing. Current knowledge of marine turtle auditory abilities is based on a few electrophysiological tests. The purpose of this study was to collect and compare behavioral and auditory evoked potential audiograms in a captive adult loggerhead turtle (Caretta caretta). The behavioral audiogram was collected using a go/no-go modified staircase method utilizing 2-second pure-tone stimuli. AEP thresholds were measured underwater using subdermal electrodes placed beneath the frontoparietal scale, dorsal to the midbrain. Action potentials were measured in response to 50 ms tonal stimuli and averaged over a maximum of 1,000 responses. Evoked potential testing yielded thresholds from 100 - 1131 Hz with peak sensitivity at 200 and 400 Hz (110 dB re 1 µPa). Behavioral testing yielded thresholds from 50 - 800 Hz with peak sensitivity at 100 Hz (98 dB re 1 µPa). Behavioral thresholds averaged 8 dB lower than AEP thresholds from 100 to 400 Hz and 5 dB higher at 800 Hz. Results indicate that behavioral and evoked potential techniques are suitable for determining marine turtle hearing sensitivity. AEP testing is a good alternative when dealing with wild or untrained animals and when time is a critical factor.

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Wright, Ruth Vivienne. "Loggerhead (Caretta caretta) and Leatherback (Dermochelys coriacea) nesting activity along the Maputaland coast (South Africa) : 1965 - 2002." Master's thesis, University of Cape Town, 2004. http://hdl.handle.net/11427/6442.

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Includes bibliographical references (leaves 59-63).
From 1963 until the present, loggerhead (Caretta caretta) and leatherback (Dermochelys coriacea) female turtles nesting on a 56-km stretch of beach in Maputaland, on the northeast coast of KwaZulu-Natal, South Africa have been tagged and monitored. In this study, population trends, size, preference for timing of nesting and nesting sites, and seasonality in nesting activity and nesting area were analysed and the effectiveness and efficiency of the monitoring programme assessed. Since the programme's inception, approximately 46893 loggerhead and 11509 leatherback females have nested on the Maputaland beaches. A non-linear relationship was found between the numbers of nesting females of both species over time, with three distinct phases. large interannual variations in nesting numbers were evident for both species, as were synchronized seasons of elevated or depressed nesting activity. While Maputaland leatherbacks appear to be approximately the same size as in populations elsewhere, the loggerhead females were significantly smaller compared to other populations. Peak nesting activity occurred from November to January and was associated with warmer sea temperatures, as was the subsequent emergence of hatchlings. Marginal temporal shifts in the nesting numbers of both species were evident during peak nesting-activity seasons, with the peak nesting period beginning slightly earlier than usual. Peak nesting-activity seasons appeared to follow EI Nino events with a lag period of between 0 and 2 years. Separate 'preferred' nesting areas were found for each species, largely associated with the offshore seabed topography. The loggerheads exhibited a fairly narrow nesting-area distribution in the north, while the leatherbacks utilised a far wider area in the southern region. The length of the 'preferred' nesting area (km) was strongly correlated with the total number of nesting loggerhead and leatherback females. No major nesting-area shifts were evident over the programme's duration. However, distinct spatial shifts, with increases in the length of the 'preferred' nesting area, were evident for both species during peak nesting-activity seasons, and was possibly related to the increased influx of nesting females. Interspecific competition appeared to be of little importance in Maputaland, as both populations displayed strong synchrony in nesting declines and increases over time, and while both populations have increased, no major shifts in the 'preferred' nesting area of either species have occurred. No correlations were found between the Southern Oscillation Index (SOl) values and nesting activity or changes in nesting area. However, a negative correlation was found between the average curved carapace lengths (CCl) of both species and the SOl values, most likely related to sea surface temperatures and the resultant changes in food availability that occur during EI Nino events. Disturbance incurred during monitoring caused, at most, only a 5% reduction in the nesting rates of both species. To date, the conservation efforts of the monitoring programme appear to have come to fruition, with both the loggerhead and leatherback nesting populations healthy and in a more-or-Iess stable state. The importance and value of continuing the current monitoring programme was emphasized, and several management and sampling strategies proposed for future seasons.

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Best, Zoey Ellen. "Environmental Factors Affecting Loggerhead Sea Turtle (Caretta caretta) Nesting, Hatching, and Incubation Patterns in Broward County, Florida." NSUWorks, 2017. http://nsuworks.nova.edu/occ_stuetd/446.

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Reproductive success in loggerhead (Caretta caretta) sea turtles is strongly dependent on the effective placement and internal conditions of their nests. Embryos rely on optimal incubation conditions for proper development and growth, which determines how many hatchlings will emerge from the nest. The internal microclimate of each nest is delicately balanced and can be easily influenced by external environmental conditions. This study was designed to examine several environmental variables and determine their effects on sea turtle nesting numbers, hatching success, and incubation conditions in Broward County Florida. Over a span of 25 years (1991-2015), the Broward County Sea Turtle Conservation Program has collected data on each sea turtle nest laid in Broward County. This data was analyzed and plotted to visualize nesting and hatching trends, and regressions were fitted to make comparisons to historic air temperature, sea surface temperature, precipitation, and lunar illumination data. These regressions were tested for significance, and each environmental variable was found to have varying levels of impact on sea turtle nesting and hatching behavior. Of the environmental variables considered in this study, analyses suggest that sea turtles are most responsive to temperature, with sea surface temperature serving as the best proxy for predicting nesting behaviors. Air temperature over the incubation period was found to be the best indicator for hatch success percentage. Air temperature, sea surface temperature, and precipitation averages all significantly affected the length of the incubation period. The regression models created in this study could be used to examine the interactions between climatic variables, and to indicate what impacts can be expected by these various environmental factors. This information could be used to estimate the future effects of climate change on sea turtle reproduction, and to predict general reproductive success and future population trends.

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Tucek, Jenny Bianka. "Comparison of the population growth potential of South African loggerhead (Caretta caretta) and leatherback (Dermochelys coriacea) sea turtles." Thesis, Nelson Mandela Metropolitan University, 2014. http://hdl.handle.net/10948/5032.

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A beach conservation programme protecting nesting loggerhead (Caretta caretta) and leatherback (Dermochelys coriacea) sea turtles in South Africa was started in 1963. As initial numbers of nesting females were low for both species (107 loggerheads and 24 leatherbacks) it was proposed that the protection of eggs, hatchlings and nesting females along the nesting beach would induce population growth and prohibit local extinction. Today, 50 years later, the loggerhead population exceeds 650 females per annum, whereas the leatherback population counts about 65 nesting females per year. The trend for leatherback turtles is that the population has been stable for about 30 years whereas loggerheads are increasing exponentially. Thus, this thesis investigated several life-history traits to explain the differing responses to the ongoing beach conservation programme. Reproductive output and success were assessed for both species; it was hypothesised that environmental conditions are sub-optimal for leatherback turtles to reproduce successfully. It was ascertained that nesting loggerhead females deposit larger clutches than leatherbacks (112 ± SD 20 eggs and 100 ± SD 23 eggs, respectively), but that annual reproductive output per individual leatherback female exceeds that of loggerhead turtles (±700 eggs and ±448 eggs, respectively) because they exhibit a higher intra-seasonal nesting frequency (leatherbacks n = 7 and loggerheads n = 4 from Nel et al. 2013). Emergence success (i.e. the percentage of hatchlings produced) per nest was similar for both species (loggerhead 73.6 ± SD 27.68 % and leatherback turtles 73.8 ± SD 22.70 %), but as loggerhead turtles nest in greater numbers, i.e. producing more hatchlings per year, the absolute population growth potential favours the loggerhead turtle. The second factor investigated was sex ratio because sea turtles display temperature-dependent sex determination (TSD) where extreme incubation temperatures can skew the sex ratio (i.e. feminising or masculinising a clutch). It was suspected that leatherback turtles are male-biased as this is the southern-most rookery (for both species). Further, leatherback nests are generally closer to the high tide mark, which might induce a cooling effect. Standard histological techniques were applied to sex hatchlings and a generalized linear model (GLM) was used to approximate annual sex ratio. Loggerhead sex ratio (2009 - 2011) was estimated at 86.9 ± SE 0.35 % female-biased; however, sufficient replication for the leatherback population was only obtained for season 2010, which indicated a 97.1 % (95 % CI 93.3 - 98.7) female bias. Both species are, thus, highly female-biased, and current sex ratio for leatherback turtles is not prohibiting population growth. Current sex ratios, however, are not necessarily indicative of sex ratios in the past which would have induced present population growth. Thus, to account for present population growth profiles, sex ratios from the past needed to be ascertained. Annual sex ratios (1997 - 2011) were modelled from historical air and sea surface temperatures (SSTs) but no significant change over time was obtained for either loggerhead or leatherback turtles (linear regression; p ≥ 0.45). The average sex ratio over this 15-year period for the South African loggerhead turtle was approximated at 77.1 ± SE 3.36 % female-biased, whereas leatherbacks exhibited a 99.5 ± SE 0.24 % female bias. Re-analysing data from the mid-80s by Maxwell et al. (1988) also indicated a 77.4 % female bias for the South African loggerhead population. It is, therefore, highly likely that sex ratios of the South African loggerhead and leatherback sea turtle populations have been stable for at least three decades and are not accountable for the differing population growth profiles as they are displayed today. Another possibility that could explain the opposed population growth profiles is the time taken for animals to replace themselves, i.e. age at maturity. It was suspected that age at maturity for the South African loggerhead turtle is comparable with that for leatherbacks. Using data from a 30-year mutilation tagging experiment (i.e. notching), age at first reproduction for South African loggerhead females was estimated. Results ranged broadly but a mean of 36.2 ± SD 7.71 years was obtained using a Gaussian distribution. Age at reproduction of the South African leatherback turtle was not determined but the literature suggests a much younger age of 13.3 - 26.8 years (Zug & Parham 1996, Dutton et al. 2005, Avens et al. 2009, Jones et al. 2011). Therefore, population growth would favour leatherback turtles as they exhibit a much shorter generation time. Finally, it was concluded that all life-history parameters investigated favour leatherback turtles, yet loggerheads are displaying population growth. However, as there were no obvious constraints to population growth on the nesting beach, it is suspected that population growth of the South African leatherback turtle is either unobserved (due to inadequate monitoring not capturing sufficient numbers of nesting events to establish a trend) or that population growth is prohibited by some offshore factor such as industrial fisheries (or some other driver not yet identified). Monitoring should, thus, be expanded and offshore mortality monitored as the leatherback population nesting in South Africa is still critically endangered with nesting numbers dangerously low.

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Broderick, Annette Cameron. "The reproductive ecology of marine turtles, Chelonia mydas and Caretta caretta, nesting at Alagadi, Northern Cyprus, Eastern Mediterranean." Thesis, University of Glasgow, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.263448.

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Laurent, Luc. "Une Approche de biologie de la conservation appliquée à la population de tortue marine caretta caretta de Méditerranée." Paris 6, 1993. http://www.theses.fr/1993PA066143.

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La biologie de la conservation d'une espèce est une véritable discipline scientifique. Son champ d'investigation se situe à l'interface des spécialités de la biologie des populations (génétique, dynamique des populations et écologie). Sa méthode consiste à définir des stratégies d'étude d'une espèce et à développer des outils permettant le recensement et l'analyse des menaces, afin de proposer des actions de conservation les plus rentables possibles. Cette méthode a été appliquée à la population de tortue marine caretta caretta de Mediterranée, selon deux approches principales, génétique et de dynamique des populations. L'utilisation d'un marqueur moléculaire (séquence d'une partie d'un gène mitochondrial) a permis d'étudier les flux géniques entrant en Méditerranée et les phénomènes de dispersion écologique. Cette étude a montré que la population méditerranéenne femelle est isolée génétiquement des populations atlantiques, mais que des tortues atlantiques sont trouvées dans le bassin occidental de la Méditerranée. Une modélisation du fonctionnement démographique de la population méditerranéenne a été entreprise, elle a débouché sur la proposition de différents modèles matriciels déterministes. Des analyses de sensibilité ont permis d'estimer les impacts des différentes pêcheries méditerranéennes (captures accidentelles). La mesure de conservation prioritaire est la protection des adultes dans le bassin oriental

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Casciaro, Valentina. "Effetto della carenza di Azoto su crescita e composizione di Phaeodactylum tricornutum." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2016. http://amslaurea.unibo.it/9762/.

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La diatomea presa in esame in questo studio è Phaeodactylum tricornutum, diatomea marina con simmetria pennata. L’interesse commerciale verso Phaeodactylum tricornutum nasce dal suo alto contenuto di acidi grassi polinsaturi (PUFA), tra cui troviamo alcuni omega 3, come l’acido eicosapentaenoico (EPA) e l’acido docosaesaenoico (DHA) e dalla quantità del polisaccaride di riserva prodotto, il β-1,3 glucano crisolaminarina. E’stata studiata la capacità dei β-1,3 glucani, in particolare della laminarina, di inibire l’attacco cellulare da parte di alcuni batteri dannosi per la salute umana. Anche i pigmenti accessori di questa diatomea in particolare il β-carotene (appartenente ai caroteni) e la fucoxantina (appartenente alle xantofille) possono essere impiegati nella nutraceutica. Negli studi svolti precedentemente sull’effetto di fattori ambientali sulla composizione di questa specie, è stata presa in considerazione solo la produzione di lipidi e non è mai stato seguito contemporaneamente l’andamento di lipidi e polisaccaridi: questo progetto di tesi prevede la valutazione della possibilità di ottenere colture di P. tricornutum ad alto contenuto sia polisaccaridico sia lipidico per applicazioni industriali. Tutto il lavoro di tesi si è svolto presso l’azienda Micoperi Blue Growth (MBG), nello stabilimento di Ortona (CH) in due fasi: nella prima fase l’esperimento è stato condotto in batch su piccola scala e la crescita e la composizione di P. tricornutum sono state seguite in due diversi terreni di coltura: uno ricco in azoto, denominato N, per mezzo del quale si è voluta incrementare la crescita e la biomassa ed uno a ridotto contenuto di azoto, denominato N/3, per indurre la produzione di lipidi e polisaccaridi. Ne è stata seguita la crescita per mezzo di misure di assorbanza, peso secco, pH, conta cellulare, determinazione dei macronutrienti ed è stata analizzata la composizione biochimica con determinazione dei composti polisaccaridici totali, determinazione qualitativa dei polisaccaridi, determinazione della clorofilla a, valutazione quantitativa e qualitativa dei lipidi. E' stato notato che la condizione con un contenuto polisaccaridico e lipidico maggiore è quella con un ridotto contenuto di azoto. Con la seconda fase si è voluto verificare la riproducibilità su larga scala di quanto notato nel primo esperimento in sistemi chiusi industriali. E’stata avviata una monocoltura di Phaeodactylum tricornutum in fotobioreattore (PBR) da 70L in semicontinuo e ne è stata monitorata la crescita misurando assorbanza, peso secco, pH, quantità di macronutrienti nel terreno; la composizione biochimica è stata valutata determinando i polisaccaridi totali e la loro composizione qualitativa, le proteine totali, i lipidi totali e la composizione qualitativa. In conclusione con questo lavoro si è visto il terreno migliore per la produzione di polisaccaridi e lipidi e le tempistiche di produzione in Phaeodactylum tricornutum, e in aggiunta, abbiamo dimostrato che sia contenuti che tempistiche sono riproducubili in un sistema industriale chiuso per produrre biomassa ad alto valore commerciale.

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Fernandes, Matilde Costa. "Antibiotic resistance and virulence profiles of gram-negative bacteria isolated from loggerhead sea turtles (Caretta caretta) of the Island of Maio, Cape Verde." Master's thesis, Universidade de Lisboa, Faculdade de Medicina Veterinária, 2021. http://hdl.handle.net/10400.5/21241.

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Dissertação de Mestrado Integrado em Medicina Veterinária
Loggerhead sea turtles (Caretta caretta) have been suggested as carriers of potential zoonotic pathogens and prime reservoirs of antibiotic-resistant and virulent bacteria. In the present study, the isolation of Gram-negative bacteria of the Cape Verdean loggerhead subpopulation, currently believed to be the largest subpopulation of this species worldwide, is described for the first time. This study aimed to characterize the aerobic and facultative anaerobic Gram-negative bacteria of the loggerhead colony of the Island of Maio, to evaluate their pathogenic potential and to unveil both the impact on sea turtles’ conservation and the underlying public health risks resulting from interactions with these animals and the consumption of turtle-derived products. Cloacal, oral and egg content swab samples from 33 nesting loggerheads (n = 99) were analysed regarding the presence of Gram-negative bacteria and the respective antibiotic resistance and virulence profiles. Conventional bacteriological techniques were applied. Shewanella putrefaciens (26.32%), Vibrio alginolyticus (21.05%) and Morganella morganii (21.05%) were the most prevalent species. A low prevalence of antibiotic-resistant bacteria (15.79%) was detected, and no multidrug-resistant isolates were identified. The identified bacterial species revealed the ability to produce numerous virulence factors, including hemolysins (100.0%), DNases (89.47%), lipases (78.95%), biofilms (73.68%), proteases (52.63%), lecithinases (21.05%), and gelatinases (15.79%). These findings suggest that due to the low anthropogenic impact observed in both their nesting (the Island of Maio) and foraging sites, this loggerhead subpopulation may be less exposed to antimicrobial compounds. Furthermore, Gram-negative bacteria isolated from these turtles may be less susceptible to acquiring resistance genes from environmental bacteria via horizontal gene transfer. Nevertheless, the presence of potentially pathogenic bacteria expressing virulence factors may threat both sea turtles’ and human’s health.
RESUMO - PERFIS DE RESISTÊNCIA A ANTIBIÓTICOS E VIRULÊNCIA DE BACTÉRIAS GRAM-NEGATIVAS ISOLADAS DE TARTARUGAS MARINHAS COMUNS (CARETTA CARETTA) DA ILHA DO MAIO, CABO VERDE - A tartaruga-marinha-comum (Caretta caretta) é conhecida por ser portadora de agentes potencialmente patogénicos e zoonóticos, e um relevante reservatório de bactérias virulentas e resistentes aos antibióticos. O presente estudo descreve, pela primeira vez, o isolamento de bactérias Gram-negativas da subpopulação de tartarugas-comuns de Cabo Verde, a qual se estima ser a maior população mundial desta espécie. Este estudo teve como objectivo a caracterização de bactérias Gram-negativas aeróbias e anaeróbias facultativas da colónia de tartarugas-comuns da Ilha do Maio, a avaliação do seu potencial patogénico e o respectivo impacto na conservação de tartarugas marinhas e do potencial risco para saúde pública, resultante de interações com estes animais e do consumo de productos derivados de tartarugas. Neste trabalho foram analizadas amostras de zaragatoas da cloaca, cavidade oral e ovos de 33 tartarugas comuns fêmeas (n = 99), de modo a isolar bactérias Gram-negativas e os respectivos perfis de resistência a antibióticos e virulência. Para o efeito, foram usados métodos de bacteriologia convencionais. As espécies isoladas mais prevalentes foram Shewanella putrefaciens (26,32%), Vibrio alginolyticus (21.05%) e Morganella morganii (21.05%). Foi detetada uma baixa prevalência de bactérias resistentes (15.79%), e não foram identificados isolados multirresistentes. As espécies bacterianas identificadas revelaram a capacidade de produzir vários factores de virulência, incluindo hemolisinas (100.0%), DNases (89.47%), lipases (78.95%), biofilmes (73.68%), proteases (52.63%), lecitinases (21.05%), gelatinases (15.79%). Os resultados deste estudo sugerem que, devido ao reduzido impacto antropogénico observado nos locais de nidificação (Ilha do Maio) e de alimentação da subpopulação em estudo, esta estará menos exposta a compostos antimicrobianos. Além disso, bactérias Gram-negativas isoladas neste estudo, poderão estar menos suscetíveis à aquisição de genes de resistência provenientes de bactérias ambientais, via transferência horizontal de genes. Contudo, a presença de bactérias potencialmente patogénicas e com a capacidade de expressar diversos factores de virulência representa uma ameaça tanto à saúde destes animais como à saúde humana.
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Roncari, Chiara. "Evaluation of microplastic content in faecal sample from hospitalized loggerhead sea turtles (Caretta caretta) of the North Adriatic Sea." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2020. http://amslaurea.unibo.it/20386/.

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Microplastics represent persistent and highly dispersal pollutants in the marine environment. The knowledge about ingestion and relative effects in large marine vertebrates, such as sea turtles, is still fragmentary. To date, studies on MP accumulation in these animals were based on the analysis of gastrointestinal tracts obtained after necropsy. In this study, we developed a protocol that allows the study of the MP through faecal material from alive turtles, that can be used in rescue centres in several locations. Specifically, faecal samples from 45 specimens of Caretta caretta, rescued along the coast of Emilia-Romagna and Marche (Italy) from 2016 to 2019 were assessed for MP content through different hospitalization periods. A unique sample was collected from 24 animals, while for 21 specimens two samples were obtained. This allowed us to quantify and characterize the MPs and to evaluate putative differences in the excreted particles during the hospitalization period. All individuals showed MPs in the faeces, for an average value of 6 ± 6.09 particles/animal. The maximum number of particles found in a single individual is 34 MPs. Filamentous particles were the most represented shape and transparent/white and red colours prevailed over the other colours. Analyses of data about first sampling show a significant negative correlation between MP number and turtle’s size. This could be due to the different feeding behaviours that occur in these animals according to their life stage. The absence of significant differences between classes and categories of shape and colours particles could be due to the high contamination of the preys in the Adriatic Sea. The absence of significant differences between the first and second sampling (where available), suggests that during the hospitalization period there might have been external influences that affected the results, including MP intake with diet, which would be considered in future studies.

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Brazier, Wayne. "Environmental cues and sensory preferences directing the nesting process in loggerhead turtles, caretta caretta, nesting in Maputaland, South Africa." Thesis, Nelson Mandela Metropolitan University, 2012. http://hdl.handle.net/10948/d1015688.

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Animals use their senses for everything on an immediate, and day to day fashion – detecting danger, finding food, finding mates among other activities. In sea turtles and other migratory species senses are used for long-distance migrations. Senses such as smell, vision and hearing, have been studied experimentally under laboratory conditions but seldom have been investigated in the field. This thesis takes a combination of field and laboratory experiments and investigates some of the hypotheses involved in natal homing and nest site selection. The loggerhead’s nesting distribution in Maputaland is distinct with characteristic high and low density nesting areas which are consistent from year to year. Investigations by earlier researchers on these beaches suggested that beach characteristics, such as beach morphodynamic type and beach width, do not appear to influence the beaches at which loggerheads emerge to nest. The high density nesting area (with approximately 440 loggerhead emergences/km) have similar beach characteristics as the low density nesting area (with <50 loggerhead emergences/km). It is therefore suggested that there is another cue that drives nest site selection. It can either be related to a physical characteristic not yet realised, or is a non-physical (but chemical or biological) cue. This dissertation aims to identify the sensory inputs received during the nest selection process, as well as sea-finding ability after nesting. To investigate the mechanism causing the high-density as opposed to the low-density nesting area, three potential drivers were investigated namely: chemical imprinting (as a natal beach cue), ambient and artificial light (as deterrents) and social facilitation (as a learned behaviour). It was also attempted to identify the strength of the most common senses – vision, hearing and smell. As animal ethics restricts interfering with emerging or nesting turtles, the strengths of these senses were tested during sea-finding by adult loggerheads. The results indicate that sulfide concentrations appear to be used as chemical cues for nesting as these concentrations are elevated (>150 percent) in the high density nesting beaches compared to the low density nesting beaches within and among seasons however further investigations are required. Artificial light (range: 0.045–0.5 lux) is an active deterrent of female emergences while ambient light, even under extreme conditions such as lightning during electric storms (up to 8.2 lux), appears to have no observable influence on the spatial or temporal distributions of emergences. Social facilitation appears unlikely as a primary nest site selection factor for loggerheads. It may however, play a minor secondary role to preferred areas or hotspots. Sea-finding in post-nesting female loggerheads appears to be driven exclusively by visual cues such as the light horizon, with minimal to no influence from other cues (the sound of the breakers, slope or smell of the ocean) which solidify the visual system’s use in sea-finding. This research on the nest site selection of loggerheads and the sensory systems involved in this process has added valuable information to the limited pool of knowledge already present and has created a solid framework on which further investigations can be based. Future work in this field should focus on integrating a suite of sensory stimuli and cues to receive a greater understanding of the sensory systems used in nest site selection.

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Dissertations / Theses on the topic 'Carezza'

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