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Pritt, Jeremy Joseph. "Defining rarity and determining the mechanisms of rarity for North American freshwater fishes". Thesis, Virginia Tech, 2010. http://hdl.handle.net/10919/31696.
Pełny tekst źródłaMaster of Science
Johnson, Jana Joan. "Butterflies, rarity, and conservation practices". Diss., Restricted to subscribing institutions, 2008. http://proquest.umi.com/pqdweb?did=1692119141&sid=1&Fmt=2&clientId=1564&RQT=309&VName=PQD.
Pełny tekst źródłaDalrymple, Sarah. "Rarity and conservation of Melampyrum sylvaticum". Thesis, University of Aberdeen, 2006. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=128181.
Pełny tekst źródłaWebb, Thomas James. "Evolutionary causes and consequences of rarity". Thesis, University of Sheffield, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.251266.
Pełny tekst źródłaLennard, Christopher James. "The causes of avian extinction and rarity". Master's thesis, University of Cape Town, 1997. http://hdl.handle.net/11427/20042.
Pełny tekst źródłaBiological extinction rates have escalated by as much as 1000 times the background extinction rate over the last 1500 years, causing concern over the long-term survival of many species. Avian extinctions since 1600 have been well documented relative to other taxa, as have current levels of avian threat. This study analyses avian extinctions post-1600 and current threats in an attempt to develop some predictive capacity about which avian taxa should be awarded the highest conservation priority. Analyses performed include examinations of the causes of avian extinction and threat, geographical location of extinct and threatened species, prehistoric and historical extinction rates, endemicity, migration, bird body size and phylogenetic diversity. An analysis dealing with historical and phylogenetic aspects of endangered and critically threatened species was performed, from which the world's most threatened species were identified. Factors which were the primary cause of historical extinctions are generally not the primary factors threatening today's extant avifauna. Whilst introduced predators and exploitation were primary causes of historical extinctions, habitat destruction poses the greatest threat to extant birds. Species predisposed to extinction typically have restricted ranges, and, compounded by habitat loss, these ranges are becoming more restricted. This has resulted in mainland-dwelling species becoming as prone to extinction as island-dwelling species have been historically. Introduced predators, however, do still threaten many of the world's most threatened species and their potential effects are highlighted in the phylogenetic analysis. Already, many extinctions may be inevitable over the next 25 years as a result of habitat loss. The magnitude of extinctions across all animal and plant species in the next few decades could be comparable with that of previous mass extinctions unless immediate conservation action is taken. However, future conservation efforts will have to be prioritized, and this study is intended as a contribution towards such a prioritization exercise.
Hoffsten, Per-Ola. "Rarity in boreal stream insects : patterns, causes and consequences /". Doctoral thesis, Umeå University, Ecology and Environmental Science, 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-142.
Pełny tekst źródłaPatterns of site occupancy among boreal stream insects were studied in central Sweden with focus on sparsely distributed species and the role of dispersal and niche limitations.
In the study of dispersal limitation, I found that effects of an extraordinarily harsh winter in small to medium-sized streams were strongest in sites located in small streams and far from lake outlets. Species richness and the total abundance of macroinvertebrates and trout returned to pre-disturbance levels after three years. However, some species showed slow recolonization and the proportion of holoaquatic taxa was still reduced after three years. In a second study, I found a positive correlation between site occupancy in stream caddisflies and morphological traits associated with fast and energy-efficient flight, whereas specialized spring caddisflies showed a negative correlation to these traits compared to stream species. This suggested that streams, but not springs, select for strong dispersal ability in caddisflies. In a survey of springs in central Sweden, hydrogeology was found to be a useful predictor of the occurrence of spring specialists. Two of these, Crunoecia irrorata Curtis and Parachiona picicornis (Pictet), were found exclusively in glaciofluvial springs, characterized by a stable discharge and temperature. Less specialized members of the spring fauna (i.e. species also occurring in streams, ponds or lakes) also occurred in moraine and limestone springs characterized by more unstable conditions.
Niche limitations were studied by contrasting large-scale distributions of closely related rare and common stoneflies. Differences in temperature requirements in the juvenile stages and life cycles suggested that the rare species, Isogenus nubecula Newman, was restricted by a limited tolerance to low stream temperatures, whereas the two common species, Isoperla grammatica (Poda) and Diura nanseni (Kempny), appeared to have a broader tolerance to climatic conditions in the study area. In a second study of niche limitations, macroinvertebrate assemblages in 88 streams in Central Sweden showed a nested distribution pattern. Most species deviating from expected distributions occurred in small streams, indicating competitive exclusion from species-rich sites, predator avoidance, or specialization to unique habitat features of small streams. In the last paper, the longitudinal distribution of filter-feeding caddisflies in a lake-outlet stream demonstrated patterns concordant to feeding specialization.
Xiang, Lan. "Interesting Association Rules Mining Based on Improved Rarity Algorithm". Thesis, Mittuniversitetet, Avdelningen för informationssystem och -teknologi, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-35320.
Pełny tekst źródłaRustage, Sarah Elizabeth. "Correlates of rarity in UK bumblebee (Bombus spp.) populations". Thesis, University of Plymouth, 2015. http://hdl.handle.net/10026.1/3372.
Pełny tekst źródłaPilgrim, Emma Susan. "The ecology of rarity : an experimental study using arable weeds". Thesis, Imperial College London, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.404578.
Pełny tekst źródłaSimmons, Mark Trevor. "Vegetation, diversity and rarity on the Cape Peninsula, South Africa". Master's thesis, University of Cape Town, 1997. http://hdl.handle.net/11427/9668.
Pełny tekst źródłaThe Cape Peninsula, (471 km²) with over 2285 vascular plant species, is characterised by the combination of a diversity of habitats supporting a mosaic of vegetation types. This study attempts to describe and explain some of the determinants of species pattern and distribution. The first part of this thesis compares a simple vegetation classification, derived from visual examination of dominant species and environmental characteristics, with the result of a multivariate classification derived from the analysis of an extensive database (835 plots, 833 species). This rapid system of classification of fynbos showed an 81 similarity with Two-Way Analysis (TWA) classification. Detrended Correspondence Analysis (DCA) and Colonial Analysis (CCA) were used to relate floristic variation to environmental factors. These analyses revealed that altitude, rainfall and soil fertility were the principle environmental factors explaining species distribution.
Handley, Richard John. "Determinants of rarity in a dioecious annual macrophyte, Najas marina L". Thesis, University of East Anglia, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.327542.
Pełny tekst źródłaWalker, Jonathan S. "Feeding ecology and rarity of frugivorous birds in tropical rain forest". Thesis, Manchester Metropolitan University, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.400944.
Pełny tekst źródłaGiles, Mark. "Patterns of Species Rarity as a Driving Mechanism for Species Richness Gradients". Thesis, Université d'Ottawa / University of Ottawa, 2020. http://hdl.handle.net/10393/40587.
Pełny tekst źródłaRebelo, Anthony G. "The preservation of the Cape flora : status, causes of rarity, ideals and priorities". Doctoral thesis, University of Cape Town, 1992. http://hdl.handle.net/11427/14229.
Pełny tekst źródłaThe Cape Floristic Region (CFR), covering 90 000 km2, comprises one of the world's six floral kingdoms. With 8600 species, of which 68 per cent are endemic, it ranks amongst the richest of temperate and tropical floras. Although 19 per cent of the CFR occurs in nature reserves, by far the majority of the preserved area comprises Mountain Fynbos. Only 0.5 and 3 per cent of the original extent of Renoster Shrub/and Lowland Fynbos is preserved, respectively. In this study Fynbos vegetation is identified as the richest habitat for Red Data Book (RDB) plant, freshwater fish, amphibian, butterfly, and reptile species in southern Africa. The greater Cape Town metropolitan area is identified as containing by far the highest richness of RDB plant, butterfly, reptile and amphibian species in the CFR Thus, this area ranks globally as one of the most urgent conservation priorities. The study also illustrates that previously used methods for evaluating priority conservation areas have under-rated species-poor areas containing a high proportion of RDB species. By collecting for species richness, a far more realistic picture of threatened areas can be obtained from RDB taxa. This study predicts, using a priori hypotheses based on ecological traits, and finds, that seed dispersal and regeneration strategies are most strongly correlated with rarity, most specifically with distributional area. Using distributional data for the Proteaceae, this study estimates that 95 per cent of all vascular plant species in Fynbos can be preserved in 16 per cent of the area. It also identifies the sites that require preservation if the maximum protection of floral diversity is to be realized. Two null models for evaluating the efficiency of a spatial configuration of reserves are proposed. Utilizing an iterating selection procedure, this study explores various algorithms, based on species richness and rarity, to construct ideal reserve configurations. This study provides the first empirical confirmation that the ideal approach to designing a reserve configuration is to identify areas of high endemism and richness in distinctive vegetation types within particular biogeographical regions. Thus, this study pioneers the use of RDB data to identify priority conservation regions, provides one of the first assessments of the causes of rarity in plants and establishes useful null models and algorithms for the identification and testing of ideal reserve locations in the design of integrated reserve networks. Not only does this study contribute towards theoretical reserve selection procedures, but it provides one of the most advanced frameworks for the preservation of a top conservation priority in the world, the CFR.
Mugodo, James, i n/a. "Plant species rarity and data restriction influence the prediction success of species distribution models". University of Canberra. Resource, Environmental & Heritage Sciences, 2002. http://erl.canberra.edu.au./public/adt-AUC20050530.112801.
Pełny tekst źródłaHopkins, Graham Wyn. "Rarity of tree aphids with particular reference to the birch aphid Monaphis antennata (Kaltenbach)". Thesis, University of East Anglia, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.338048.
Pełny tekst źródłaHenfield, Malik S. ""I am a rarity in my school" hidden obstacles for African Americans in gifted education /". Columbus, Ohio : Ohio State University, 2006. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1155752723.
Pełny tekst źródłaMills, Michelle Holland. "Correlates of rarity in the flora of North America : life histories, habitats, and geographic distributions /". For electronic version search Digital dissertations database. Restricted to UC campuses. Access is free to UC campus dissertations, 2003. http://uclibs.org/PID/11984.
Pełny tekst źródłaMcKenna, David J. "Demographic and ecological indicators of rarity in a suite of obligate-seeding Persoonia (Proteaceae) shrubs". Access electronically, 2007. http://www.library.uow.edu.au/adt-NWU/public/adt-NWU20080131.142010/index.html.
Pełny tekst źródłaMartin, Lynn. "Factors contributing to the rarity and threatened status of the Large Copper butterfly (Lycaena dispar batavus)". Thesis, Keele University, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.341238.
Pełny tekst źródłaCioffi, Rebekah Katie Elizabeth. "Understanding rarity and latitudinal range relationships in European diving beetles (Dytiscidae) using metabolic plasticity and immunocompetence". Thesis, University of Plymouth, 2017. http://hdl.handle.net/10026.1/9480.
Pełny tekst źródłaYenni, Glenda Marie. "Self-limitation as an explanation for species' relative abundances and the long-term persistence of rare species". DigitalCommons@USU, 2013. https://digitalcommons.usu.edu/etd/1958.
Pełny tekst źródłaMunagani, Indira Priya Darshini. "Mining Rare Features in Fingerprints using Core points and Triplet-based Features". Thesis, Virginia Tech, 2014. http://hdl.handle.net/10919/24784.
Pełny tekst źródłaMaster of Science
Knapp, Sonja. "Plant biodiversity in urbanized areas analyses of plant functional traits in space and time, plant rarity and phylogenetic diversity". Wiesbaden Vieweg + Teubner, 2009. http://d-nb.info/995192685/04.
Pełny tekst źródłaMcCue, Kimberlie A. "The ecological genetics of rarity : a study of genetic structure, inbreeding and seed bank dynamics in a rare annual plant /". free to MU campus, to others for purchase, 1997. http://wwwlib.umi.com/cr/mo/fullcit?p9841324.
Pełny tekst źródłaLine, Eric R. "Effects of Landscape Aggregation and Landscape Conversion on Bird Diversity in Ohio from 2013-2017". Bowling Green State University / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1621604319860423.
Pełny tekst źródłaKilani, Asma. "Le rôle des restrictions temporelles de vente sur l'évaluation de l'offre et l'intention d'achat : analyse par méthode des scénarios". Thesis, Strasbourg, 2017. http://www.theses.fr/2017STRAB014/document.
Pełny tekst źródłaThe role of the sales restrictions on the evaluation of the offer and the intention of purchase still stays controversial. The marketing literature is divided over the subject and sets up different conceptual frames and theories explaining the effects of these restrictions. Facing the lack of unanimity in literature, in a context where the rentability of sales promotions is not established, this thesis aims to a better comprehension of the impact of the temporal limits on the evaluation of a promotional sales offer and the intention of the consumer's purchase. This survey was made through a mixed methodology made by an exploratoring study lead by focus groups and by a quantitative study lead by the scanario method. The results of our explorating survey underline an ambivalent behaviour versus the temporal restriction of sales. Our empiric study reveals a moderating role of the brand able to limit the perception of the drawbacks in the space of the time restrictions of sales
Müller, Gregor Simon [Verfasser]. "Testing the relative roles of competition and plant-soil feedback in explaining commonness and rarity of alien and native plant species / Gregor Simon Müller". Konstanz : Bibliothek der Universität Konstanz, 2017. http://d-nb.info/1138566349/34.
Pełny tekst źródłaFox, Call Christina Elizabeth. "Population Structure, Genetic Diversity, Geographic Distribution, and Morphology of Two Boechera (Brassicaceae) Parental Species (Boechera thompsonii and Boechera formosa) and of Their Resultant Hybrid Boechera duchesnensis". BYU ScholarsArchive, 2016. https://scholarsarchive.byu.edu/etd/6233.
Pełny tekst źródłaBarreto, Bruno de Souza. "Biogeografia da conservação de morcegos no cerrado brasileiro". Universidade Federal de Goiás, 2008. http://repositorio.bc.ufg.br/tede/handle/tede/3178.
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Fundação de Apoio à Pesquisa - FUNAPE
The units of conservation are main strategy adopted by the rulers to guarantee that the negative effects of the socioeconomic development reach less the biodiversity. recent researches have been trying to outline the problem through reserve selection that seek larger representativeness of the goals of conservation (in general some estimador of the biodiversity as the species) in terms of a smaller number of areas as possible. in the last 50 years the cerrado is going by transformations in their natural landscapes due to the progress of the modern agriculture and of the livestock. due to that, the objective of that work was to define priority areas network for conservation of bats in terms of five conservation sceneries differents. the generated nets were restricted by socioeconomic cost, presence of cave and a cost that considers the previous two cost. the results revealed main features of analyses of complementarity: multiple solutions, flexibility of the nets, and influence of the rarity of the species for the definition of groups starting from the pattern of rarity. the costs were important for definition of nets that avoided as much conflicts of conservation as prioritized the species in areas of cave.
As unidades de conservação são principal estratégia adotada pelos governantes para garantir que os efeitos negativos do desenvolvimento socioeconômico atinjam menos a biodiversidade. recentes pesquisas têm tentado contornar o problema através de seleção de reservas que visam maior representatividade das metas de conservação (em geral algum estimador da biodiversidade como as espécies) em termos de um menor número de áreas quanto possível. nos últimos 50 anos o cerrado vem passando por transformações em suas paisagens naturais em decorrência do avanço da agricultura moderna e da pecuária. os morcegos são também ameaçados e em decorrência disso, o objetivo desse trabalho foi definir redes de reservas regionais prioritárias para conservação de morcegos em termos de cinco cenários de conservação diferentes. as redes geradas foram restringidas por custo socioeconomico, custo presença de caverna e custo que podera os dois anteriores. os resultados reelaram as principais caracteísticas de análises de complementaridade: multiplas soluçoes, flexibilidade das redes, influência da raridade das espécies pela definição de grupos a partir do padrão de raridade. os custos foram importantes para definição de redes que evitaram tanto conflitos de conservação quanto priorizaram as espécies em regioes de caverna.
Sgarbi, Luciano Fabris. "Determinantes da raridade das espécies e seus efeitos sobre a estrutura de comunidades biológicas". Universidade Federal de Goiás, 2018. http://repositorio.bc.ufg.br/tede/handle/tede/8612.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES
A recurrent pattern seen in nature is that species vary in abundance among sites, being common in a few sites and rare at the majority of sites. This intraspecific distribution of abundance, in turn, generates an excess of rare species in biological communities. This excess may cause problems in data analyses as datasets include many zeros. In this thesis I studied the causes of species rarity and how the excess of rare species influence the detection of patterns at the community level. In the first chapter I observed that species classified as rare were common in other habitat types, in other sites elsewhere, and in other years. However, among these three factors, the rarity was explained mainly by the habitat type. In the second chapter I observed that species tend to become rarer as they distance themselves (above, below or in both directions) from their optimal elevation. This pattern was quite robust and independent of taxonomic group or geographic region. In the third chapter, I observed that remotion of rare species in general did not have effects on the recovery of community structure patterns. In addition, the effect of that remotion of rare species was similar to that observed for the common species exclusion or random species exclusion.
Um padrão repetidamente observado na natureza é que as espécies variam em abundância entre os locais, sendo que em poucos locais a espécie é abundante, enquanto que na maioria a espécie é rara. Esta distribuição intraespecífica de abundância, por sua vez, gera um padrão recorrente que é o excesso de espécies raras nas comunidades biológicas. Este excesso de espécies raras pode complicar análises ao nível de comunidade visto que produzem conjuntos de dados com muitos zeros. Nesta tese busquei entender quais são as causas para a raridade das espécies e como excesso de espécies raras influência a detecção de padrões ao nível de comunidades. No primeiro capítulo observei que espécies classificadas como raras, foram comuns em outros habitats, em outros locais e em outros anos. No entanto, entre estes três fatores, a raridade foi melhor explicada pelo tipo de habitat em que ela foi amostrada. No segundo capítulo observei que as espécies tendem a se tornar mais raras conforme elas se distanciam (acima, abaixo ou em ambas as direções) de sua elevação ótima. Este padrão foi bastante robusto pois foi independente do grupo taxonômico ou da região geográfica. No terceiro capítulo, observei que a remoção das espécies raras têm pouco efeito na recuperação dos padrões de estrutura das comunidades. Além disso, o efeito da remoção de espécies raras foi similar ao observado quando exclui as espécies comuns, ou exclui as espécies de forma aleatória.
Bender, Gomes Mariana. "La structuration des communautés de poissons de récif à différentes échelles : de la taxonomie aux fonctions". Thesis, Montpellier 2, 2014. http://www.theses.fr/2014MON20073/document.
Pełny tekst źródłaUnderstanding the mechanisms of community assembly is one of the main questions in ecology and biogeography, and is essential for predicting the implications of future biodiversity loss. It is known that an array of processes operating at different spatial and temporal scales interact to produce ecological communities. These processes may affect differently the multiple components of communities: the taxonomic, functional and phylogenetic components. Here we investigate the patterns and processes structuring one of the most diverse vertebrate assemblages on Earth: reef fishes. Reef fish assemblages were assessed across multiple spatial scales, under a taxonomic and functional perspective. Our main objectives included: (i) the identification of determinants of structure in reef fish assemblages across scales (regional to local); (ii) assessing to which extent the processes behind assemblage structures are consistent for taxonomic and functional groups; (iii) understanding the patterns of functional rarity in reef fish assemblages at a global scale. Two databases were utilized: (1) an extensive database on the functional traits and the global distributions of over 6,000 reef fish species across six marine biogeographic regions; (2) a dataset comprising the occurrences of 1,474 fish species over 9,681 underwater visual transects of 40m2 across 252 sites, also throughout the major biogeographic regions. Within the Atlantic Ocean, the taxonomic and functional structure of reef fish assemblages exhibit a biogeographic fingerprint, with a marked discrimination between species rich biogenic reefs – primarily in the Caribbean, where communities were dominated by small invertebrate feeders – and poorer peripheral regions dominated by larger species with more diverse diets. At the regional scale, both historical events and environmental characteristics (coral reefs vs. periphery) have played a role in structuring both components of assemblages. The role of environment features also holds for the structure of assemblages in other biogeographic realms (i.e. Indo-Pacific and Tropical Eastern Pacific). While the taxonomic composition of assemblages is mainly related to reef isolation, the functional structure is influenced by local habitat availability. Again, there is a greater contribution of small-bodied species in the most species-rich locations; and large-bodied species prevailing in peripheral assemblages, a pattern related to species' colonization capacity. Reef fish assemblages across most regions depicted significantly functional nested structures, attributed to functional redundancy – different species constitute a number of key functional entities. The nested structure results from the interaction between species' dispersal/colonization capabilities and/or resource requirements, with isolation and area gradients. Despite the existence of key functional groups and redundancy, the majority of species are rare (low abundance or occupancy). Also, rare species fulfil much of the range of functional traits within reef fish communities and often perform unique roles. Under scenarios of rare species loss (from 8 to over 200 rare species/ mean: 78.2±62) there would be high functional diversity erosion in the majority of reef fish communities, this level reaching up to 80% of functional diversity in one location. However the extent to which these functional groups actually contribute to ecosystem functioning is unknown. Our results reveal that within-realm processes, such as evolutionary histories, have shaped the taxonomic and functional structure of assemblages in each realm. Moreover, the key role of species' colonization capacity highlights the importance of connectivity to the maintenance of the functional structure across reef fish communities. Finally, the contribution of rare species to functional diversity indicates that protecting these taxa is essential to maintain ecosystem functioning and services in reef fish communities
Craig, Tracy-Ann. "Kidney stone rarity in South Africa's black population : investigation of the biochemical and physico-chemical properties of Tamm Horsfall Mucoprotein as a possible contributory factor". Doctoral thesis, University of Cape Town, 2004. http://hdl.handle.net/11427/7443.
Pełny tekst źródłaTamm Horsfall mucoprotein (THP) is a powerful inhibitor of calcium oxalate crystallisation. Since urolithiasis in South African blacks is extremely rare, this study was undertaken to compare the relative inhibitory and biochemical properties of this protein in South African black and white healthy and stone—forn1ing male subjects. THP was isolated by salt precipitation, purified by column chromatography and verified by electrophoresis on SDS-polyacrylamide gels. MALDI-TOF mass spectroscopy was used to determine the molecular weights of the protein from each group and their respective amino acids were analysed. All four THP groups were subjected to tryptic finger printing digestion and matched those of the database. The secondary structures of the four THP proteins were also determined using circular dichroism. The carbohydrate moeities of the four THP groups were analysed for and O-linked oligosaccharides. THP from each of the four groups were subjected to a series of crystallisation experiments using a crossover design in which the protein was added to the urine from which it had been originally isolated, as well as to the urines from the other three groups. This process generated a 4x4 protein-urine grid for investigation of the inhibitory properties of THP in different urine environments. Calcium oxalate crystallization was induced by administration of aqueous sodium oxalate and was monitored Using a Coulter Counter. In another series of experiments 14C-oxalate was used to initiate crystallization. Monitoring in these experiments was achieved by scintillation counter techniques. Calcium oxalate crystal aggregation was investigated in the presence and absence of THP using zeta potential measurements and crystal sedimentation experiments.
Haydu, Kristie. "Mapping Plant Biodiversity Hotspots at the County Scale: A New Tool for Establishing Resource Conservation Strategies". DigitalCommons@CalPoly, 2012. https://digitalcommons.calpoly.edu/theses/749.
Pełny tekst źródłaBULINSKI, KATHERINE VICTORIA. "Relationship of sample-level properties to biodiversity at multiple scales: analyses of Upper Ordovician and Cenozoic ecological and latitudinal gradients". University of Cincinnati / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1212001254.
Pełny tekst źródłaIannuzzi, Victoria N. "School Shootings in the United States from 1997 to 2012: A Content Analysis of Media Coverage". Scholar Commons, 2017. http://scholarcommons.usf.edu/etd/6866.
Pełny tekst źródłaWilliams, Aleida Helen. "An ecophysiological comparison of rare ironstone endemics and their common congeners". University of Western Australia. School of Plant Biology, 2008. http://theses.library.uwa.edu.au/adt-WU2008.0241.
Pełny tekst źródłaNakamura, Nodoka. "Dissecting the Japanese hotspot : refining evaluation of biodiversity in forests at different scales in the Japanese landscape". Thesis, University of Oxford, 2013. http://ora.ox.ac.uk/objects/uuid:c625c75e-b983-48ab-b8c8-fbe0cea0d53e.
Pełny tekst źródłaPalazy, Lucille. "La chasse aux trophées : menace ou alliée pour les espèces rares". Thesis, Lyon 1, 2013. http://www.theses.fr/2013LYO10020/document.
Pełny tekst źródłaTrophy hunting, which is a form of recreational hunting with the main objective of collecting a trophy of interest, is a controversial subject. This activity could potentially generate an anthropogenic Allee effect (AAE). This demographic process states that the valuation of rarity could drive rare species exploitation and even lead to their extinction. Our project aims at testing the potential for an AEE in trophy hunting. We demonstrate that rare species have a high financial value, regardless of the trophy size, indicating that there is a high demand for those species. We also show that the number of trophies traded internationally and the number of recorded trophies by the Safari Club International (one of the largest clubs for international trophy hunters in the USA) rises as the degree of rarity (as measured by a rarity index) increases. Trophy hunting of rare species has been proposed as a tool to fund their conservation. However, our results indicate that there is a risk of an AAE for rare species. Furthermore, the combined effects of trophy hunting, illegal hunting, corruption as well as the lack of population knowledge and of management controls have potential to result in the unsustainable exploitation of rare species of high financial value. Nonetheless, trophy hunting has potential to generate strong financial incentives that are necessary for wildlife preservation. Such incentives are only likely to be effective if strict measures are required and enforced to prevent overexploitation of rare trophy species
Kondratyeva, Anna. "Measuring inter-specific diversity. Benefits of species originality indices in community ecology and conservation biology". Thesis, Paris, Muséum national d'histoire naturelle, 2019. http://www.theses.fr/2019MNHN0012.
Pełny tekst źródłaHumanity strongly depends on biodiversity and services it provides. To prevent the biodiversity loss and to establish sustainable relations with nature humanity has to efficently manage and protect natural resources. The problem of “what to protect” is not new but became more important than ever and could be resolved by an appropriate use of biodiversity measures. Many indices of biodiversity have been developed in the last four decades, with species being one of the central units. However, evolutionary and ecological studies need a precise description of species’ characteristics to best quantify inter-species diversity, as species are not equivalent and exchangeable. First measures taking into account species biological differences were based on species phylogenetic relations and trait values. However, many of them measure a diversity of a set of species, and does not indicate the respective contribution of each species to the diversity of the set. To find a remedy to this issue, other type of measures appeared in early 90’s, comparing species through the shared amount of characteristics, but were put aside, erroneously classified as diversity measures too. In this thesis we refer to these measures as species originality indices. A species is original if it possesses unusual trait values compared to all others in a community or if it is distantly related with other species in a community. Thus, the most original species have the greatest contribution to the diversity of that community. In this thesis we sought to demonstrate the benefits of originality metrics, particularly in conservation biology and community ecology. First we review the relation of species originality with concepts of species’ diversity and rarity and we compare their related measures. Following theoretical links between originality and diversity measures we propose a practical application of a two-step (and two-scale) originality framework to a real plant species data. Finally, we discuss main pitfalls and advantages related to species data, spatial scale of a study and the choice of an originality measure. Future studies could use originality measures with other entities than species, such as genes or habitats, and therefore broad the extent of biodiversity assessment and conservation
Vanderplank, Sula E. "The Vascular Flora of Greater San Quintín, Baja California, Mexico". Scholarship @ Claremont, 2010. http://scholarship.claremont.edu/cgu_etd/2.
Pełny tekst źródłaFerreira, Tiago de Souza. "Raridade de espécies arbóreas em fragmentos florestais no Planalto Sul Catarinense". Universidade do Estado de Santa Catarina, 2013. http://tede.udesc.br/handle/handle/1919.
Pełny tekst źródłaThis study was conducted in different fragments in Planalto Sul Catarinense distributed in along an altitudinal gradient. The objective of the first chapter was to identify local rarity patterns and its proportions, basing on characteristics of habitat range and population size. For this, a vegetational matrix of tree species abundance, from 11 sampling units distributed in different forest fragments in Planalto Sul Catarinense region, was elaborated. In each of sampling plots all living tree individuals with diameter at breast height (dbh) greater than or equal to 5cm were counted and identified. The local rarity patterns were defined through a grid of descriptors used to classify the species in four categories: NE = non-specific species; R1 = scarce euryecious species; R2 = non-scarce stenoecious species; R3 = scarce stenoecious species. From all 144 analyzed tree species, 92 (63.89%) were classified as non-specific (NE). The rarity form R1 demonstrated 5 (3.47%) species, the rarity form R2 showed 33 (22.92%) species and the form R3 had 14 (9.72%) species. The most important conditioning of rarity was habitat preference, i.e., stenoecious species, represented in rarities forms R2 and R3. The species classified in rarity form R3 are those that require the most concentrated efforts in conservation measures. In the second chapter the present study aimed to analyze how the distribution and the richness of rare tree species occurs along an altitudinal gradient, in Araucaria Forests fragments. For this, tree species (diameter at breast height ≥ 5 cm) were sampled in 10 forest fragments located on different altitudinal floors in Planalto Sul Catarinense region, totaling 10ha of sampling area. The species with only one or two individuals in at least one fragment were classified as rare. The species distribution was verified by a dendrogram constructed through the Jaccard floristic distance index and the UPGMA clustering algorithm. The total species richness per forest fragment and the number of rare species was compared among montane and upper-montane sub-formation by the Mann-Whitney (U) test. The relationship between the altitude and the values of total richness and number of rare species in each fragment were determined by simple linear regressions. The results indicated the formation of two groups of rare species, in function of the altitude floor. Despite the total richness of communities decreases with increasing altitude, the number of rare tree species did not change significantly. We conclude that in the Planalto Sul Catarinense region, the fragments of Araucaria Forest have different set of rare species according to altitude and that the reduction of the richness of communities with increasing altitudinal floor is not accompanied by a reduction in the number of rare species
Este trabalho foi realizado na região fito-ecológica do Planalto Sul Catarinense em fragmentos localizados em diferentes cotas altitudinais. O primeiro capítulo teve como objetivo identificar os padrões de raridade local e suas proporções, com base nas características de amplitude de habitat e tamanho populacional. Para isso, foi elaborada uma matriz vegetacional de abundância de espécies arbóreas a partir de 11 unidades amostrais distribuídas em diferentes fragmentos florestais na região do Planalto Sul Catarinense. Em cada unidade amostral foram contados e identificados todos os indivíduos arbóreos que apresentaram diâmetro na altura do peito (DAP) igual ou superior a 5 cm. Para definir os padrões de raridade local foi utilizada uma grade de descritores que classificou as espécies em quatro categorias: NE= espécies não-específicas; R1= espécies escassas eurióicas; R2= espécies não-escassas estenóicas; R3= espécies escassas estenóicas. Das 144 espécies arbóreas analisadas, 92 (63,89%) foram não-específicas (NE). A forma de raridade R1 apresentou cinco (3,47%) espécies, a forma R2 apresentou 33 (22,92%) espécies e a forma R3 apresentou 14 (9,72%) espécies. O condicionante mais importante da raridade foi a preferência por habitat, ou seja, espécies estenóicas, representadas nas formas de raridade R2 e R3. As espécies classificadas na forma de raridade R3 são as que mais necessitam concentração de esforços em medidas de conservação. O segundo capítulo buscou verificar como a distribuição e a riqueza de espécies raras ocorrem em fragmentos de Floresta Ombrófila Mista, ao longo de um gradiente altitudinal. Foram amostradas espécies arbóreas (diâmetro na altura do peito ≥ 5cm) em 10 fragmentos florestais localizados em diferentes pisos altitudinais do Planalto Sul Catarinense, numa área total de 10ha. As espécies que apresentaram número de indivíduos igual ou inferior a dois em pelo menos um fragmento foram classificadas como raras. A distribuição das espécies foi verificada por meio de um dendrograma construído a partir do índice de distância florística de Jaccard e o algoritmo de agrupamento UPGMA. A riqueza total de espécies por fragmento florestal e o número de espécies raras foi comparada entre as subformações Montana e Alto-Montana por meio do teste de Mann-Whitney (U). As relações entre a altitude e os valores de riqueza total e número de espécies raras em cada fragmento foram determinadas por meio de regressões lineares simples. Os resultados indicaram a formação de dois grandes grupos de espécies raras, em função do piso altitudinal. Apesar da riqueza total das comunidades diminuir com o aumento da altitude, o número de espécies raras não apresentou alterações significativas. Conclui-se que na região do Planalto Sul Catarinense, os fragmentos de Floresta Ombrófila Mista apresentam diferentes conjunto de espécies arbóreas raras de acordo com altitude e que a redução da riqueza das comunidades com o aumento do piso altitudinal não é acompanhado pela redução do número de espécies raras
Lin, Wuying. "Comparative Reproductive Biology of a Rare Endemic Orchid and its Sympatric Congeners in Southwestern China". FIU Digital Commons, 2012. http://digitalcommons.fiu.edu/etd/570.
Pełny tekst źródłaHong, Ellen. "Understanding the Antecedents of Perceived Authenticity to Predict Cultural Tourists’ Behavioral Intention: The Case of Cambodia’s Angkor Wat". Ohio University / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1620270040944891.
Pełny tekst źródłaDeppa, Ntsapokazi. "Rarity of kidney stones in South Africa's black population : studies of urinary macromolecules, crystal matrix extract containing osteopontin, and bone turnover markers in urine and serum from black and white subjects as a key to understanding this paradox". Doctoral thesis, University of Cape Town, 2007. http://hdl.handle.net/11427/19147.
Pełny tekst źródłaTeshima, Fernanda Ayumi. "Ecologia das assembleias de peixes do Parque Estadual de Jurupará (PEJU,SP)". Universidade Federal de São Carlos, 2013. https://repositorio.ufscar.br/handle/ufscar/1527.
Pełny tekst źródłaFinanciadora de Estudos e Projetos
The general aim of this thesis is to understand the fish assemblages of headwater and small streams of Jurupará State Park, a protected area located in São Paulo State. Located among other four protected areas, the park functions as a connector and contributes to the conservation of the Atlantic Forest and Upper Juquiá River basin, located in the Ribeira de Iguape River basin. Ten stream reaches (3rd to 5th order) were sampled between June and December 2010. Ichthyofauna was collected with electrofishing equipment, while environmental variables were visually quantified during onsite surveys and with cartographic maps of the region. Local environmental variables consisted of coarse substrate, diversity of water velocity, proportion of mesohabitats (i.e., riffles, pools and runs), banks stability and shading. Regional environmental variables consisted of vegetation cover, catchment area, altitude and stream reach position according to sub-basin. Fish assemblages structure analyses according to environmental variables were divided into two chapters, presented as scientific papers. The first chapter analyzed two issues, (i) fish assemblages α and β components and (ii) patterns in species composition according to environmental variables. In order to approach the first issue, we used multiplicative partitioning of true diversities to calculate α and β components and compare them with expected values in a null model. The second issue was approached by reducing the number of environmental variables with PCA and using the most significant gradients as predictor variables in a db-RDA, followed by a species composition variation partitioning according to each significant variable. The α and β components observed were different from expected by chance and the variation in species composition was strongly related to environmental variables operating at different scales. The proportion of coarse substrate and bank stability contributed with 6% of species composition variation, while sub-basin contributed with 10%. Possibly, the low percentage of variation explained by the model can be justified by the scale of the environmental variables. If the structuring of fish assemblages follows the null metacommunity model predictions, then variables related to stream topology and species intrinsic characteristics are more likely to better explain the spatial organization of the fauna. In Chapter II, we used data of occurrence frequency, average abundance and biomass to identify rare and common species of the fish assemblages. Withal, we used linear multiple regression models to analyze the abundance of Isbrueckerichthys epakmos according to local environmental variables. The importance of this species relies on its classification as endemic in Ribeira de Iguape River basin and threatened, according to IUCN criterion. Five species were very abundant and widely distributed in the sampled reaches, including I. epakmos, whose distribution was strongly related to coarse substrate and proportion of riffles and runs. Eight rare species were identified, two of them being also endemic of Ribeira de Iguape River basin, Astyanax ribeirae e Neoplecostomus ribeirensis. The elevated taxonomic and functional diversity observed indicates that the studied streams still hold physical integrity to support the biota and, probably, local ecological processes, despite the presence of impoundments that support four small dams installed inside the park.
O objetivo geral desta dissertação é entender as assembleias de peixes dos riachos de cabeceiras e pequeno porte do Parque Estadual do Jurupará, uma unidade de conservação de proteção integral do estado de São Paulo. Localizado entre outras quatro áreas protegidas, o parque possui função conectora e contribui para a conservação da Mata Atlântica do estado, além de contribuir para a proteção da bacia do Alto Rio Juquiá, inserida na bacia hidrográfica do Rio Ribeira de Iguape. Dez trechos de riachos (3ª a 5ª ordem) foram amostrados entre junho e dezembro de 2010. A ictiofauna foi coletada com equipamento de pesca elétrica, enquanto variáveis ambientais foram mensuradas em campo e com bases cartográficas da região. As variáveis ambientais consideradas de atuação local foram substrato grosso, diversidade de velocidades, proporção de mesohábitats (i.e, corredeiras, poções e rápidos), estabilidade das margens e sombreamento. As variáveis ambientais de atuação regional foram vegetação no entorno, área à montante do trecho amostrado, altitude e posição do riacho de acordo com a sub-bacia hidrográfica. As análises da estrutura das assembleias ícticas em função das variáveis ambientais foram divididas em dois capítulos, apresentados na forma de artigos científicos. O primeiro capítulo tratou de duas questões, (i) as diversidades α e β das assembleias de peixes dos riachos e (ii) padrões na composição de espécies em função das variáveis ambientais. Para analisar a primeira questão, aplicamos a relação multiplicativa proposta por Whittaker, utilizando a diversidade equivalente de Shannon, para calcular os componentes α e β e comparamos os valores obtidos com o esperado em um modelo nulo. Para a segunda questão, reduzimos o número de variáveis ambientais com uma PCA e os eixos mais significativos foram utilizados como variáveis preditoras em uma db-RDA, seguida do particionamento da variação da composição de espécies de acordo com cada variável significativa. As diversidades α e β dos riachos foram diferentes do esperado ao acaso e a variação na composição de espécies esteve relacionada a variáveis ambientais que atuam em diferentes escalas. A proporção de substrato grosso no canal e a estabilidade das margens contribuíram com 6% na variação da composição de espécies, enquanto que a posição do riacho de acordo com a subbacia contribuiu com 10%. Possivelmente, a baixa porcentagem de variação explicada pelo modelo pode ser justificada pela escala das variáveis selecionadas. Se a estruturação das assembleias de peixes seguir as previsões do modelo nulo da teoria de metacomunidades, é provável que variáveis relacionadas à topologia da bacia hidrográfica e às características intrínsecas das espécies sejam mais eficientes em explicar a organização espacial da fauna. No segundo capítulo, utilizamos dados de frequência de ocorrência, abundância média de indivíduos e representatividade em massa para identificar as espécies raras e mais comuns das assembleias. Paralelamente, utilizamos modeloslineares de regressão múltipla para analisar a abundância de Isbrueckerichthys epakmos em função de variáveis ambientais locais. O interesse nessa espécie justifica-se por sua classificação como endêmica da bacia do Rio Ribeira de Iguape e ameaçada de extinção, segundo os critérios da IUCN. Cinco espécies foram muito abundantes e amplamente distribuídas nos riachos estudados, entre elas I. epakmos, cuja distribuição esteve fortemente relacionada à proporção de substrato grosso e poções e corredeiras. Oito espécies raras foram identificadas, sendo duas endêmicas da bacia do Rio Ribeira de Iguape, Astyanax ribeirae e Neoplecostomus ribeirensis. A elevada diversidade taxonômica e funcional observada indica que os riachos amostrados ainda apresentam integridade física capaz de sustentar a biota e, provavelmente, os processos ecológicos locais, apesar da presença dos represamentos no interior do parque que abastecem quatro pequenas centrais hidrelétricas.
Marcilhac, Vincent. "Le luxe alimentaire français. Histoire et géographie d’une singularité". Thesis, Paris 4, 2011. http://www.theses.fr/2011PA040203.
Pełny tekst źródłaThe prominence of France in the food luxury sector is often presented as a given. But other food luxury cultures have existed and still exist. So why and how has the French culture of food luxury differentiated itself from others by affirming itself and being recognized as a singularity? Behind the seeming evidence, it is important to demonstrate and explain the hypothesis of a French singularity in the matter of food luxury. Today, this singularity is called into question because of its own market extension linked to the industrialization of its production, to the diversification of its distribution channels, to the international reach of its consumption, as well as to the rise of a new competition and the evolution of society. So is it still relevant today to talk about "French food luxury"? Beyond marketing, this raises the challenge of maintaining a creativity, a culture of consumption and a know-how quintessentially French. Today, the patrimonial and touristic valuation of the production sites contributes to the recognition of originality, rarity and excellence of luxury food products. This valuation is also a mean for territorial development
Matlock, Peter. "The Rarita-Schwinger field and the AdS/CFT correspondence". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape9/PQDD_0026/MQ51412.pdf.
Pełny tekst źródłaCundy, Mark A. "The Rarita-Schwinger equation in algebraically special space-times". Thesis, University of Oxford, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.365285.
Pełny tekst źródłaPais, Hirigoyen Pablo. "Unconventional Supersymmetry, Massless Rarita-Schwinger Theory and Strained Graphene". Doctoral thesis, Universite Libre de Bruxelles, 2017. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/258427.
Pełny tekst źródłaDans cette Thèse, nous nous proposons d'analyser trois aspects différents de la Physique Fondamentale.La première partie est consacrée à l'éude détaillée de ce qu'on appelle "supersymétrie non conventionnelle" à trois et quatre dimensions pour des groupes internes abéliens et non abéliens. Nous montrons le contenu dynamique de la théorie de la dimension impaire, comptant en même temps les degrés de liberté locaux pour certains secteurs particuliers de l'espace des phases. Dans le cas tridimensionnel non-abélien, certaines solutions de trous noirs sont présentées, y compris leurs spinors de Killing. En quatre dimensions, la supersymétrie est brisée explicitement et un Lagrangien de Dirac standard couplé à l'électromagnétisme et à la géométrie d'arriére-plan est obtenu.Dans la deuxième partie, le contenu dynamique de la théorie de Rarita-Schwinger libre et couplée à un champ de jauge sans masse est présenté. Nous sommes en mesure de le faire par le formalisme Hamiltonien de Dirac et la méthode dite de Faddeev-Jackiw, en montrant en même temps les symétries de la théorie. Il est démontré que dans la théorie étendue de jauge, qui comprend des champs fermioniques supplémentaires pour restaurer les symétries fermioniques du cas libre, l'anticommutator du champ Rarita-Schwinger dans la quantification canonique n'est pas définiti positif en général.Comme le graphène a été proposé comme un "laboratoire de table" pour certains scénarios de gravité quantique, dans la troisième partie de cette Thèse, nous clarifions certaines caractéristiques subtiles du graphène sous tension afin de gérer correctement ce matériel. Nous montrons en particulier que le champ pseudo-magnétique induit par le champ tensoriel de déformation dans le plan ne peut pas émerger d'une théorie de champ quantique dans un espace courbe (approche bottom-up), mais bien à partir de l'analyse détaillée de l'Hamiltonien tight-binding des pi électrons dans le graphène (approche top-down).
En esta Tesis se propone analizar tres aspectos diferentes de la Física Fundamental.La primera parte está dedicada al estudio detallado de lo que ha pasado a llamarse "supersimetría no convencional" en tres y cuatro dimensiones para grupos internos abelianos y no abelianos. Se muestra el contenido dinámico en dimensiones impares de la teoría, contando al mismo tiempo los grados de libertad locales para ciertos sectores del espacio de fases. En el caso tridimensional no abeliano, se presentan algunas soluciones de agujeros negros, incluyendo sus espinores de Killing. En cuatro dimensiones, la supersimetría está rota explícitamente y se obtiene un lagrangiano estándar de Dirac acoplado con el campo electromagnético y la geometría de fondo.En la segunda parte, se presenta el contenido dinámico de la teoría de Rarita-Schwinger libre y con acoplamiento gauge. Esto se puede hacer a través del formalismo hamiltoniano de Dirac y el método de Faddeev-Jackiw, mostrando al mismo tiempo las simetrías de la teoría. Se observa que en la teoría gauge extendida, la cual incluye campos fermiónicos extra para restaurar la simetría fermiónica del caso libre, el anticonmutador del campo de Rarita-Schwinger no es definido positivo en la cuantización canónica.Ya que el grafeno se ha propuesto como una "mesa de laboratorio" para algunos escenarios de gravedad cuántica, en la tercera parte de esta Tesis se clarifican algunas características sutiles del grafeno extendido con el objetivo de manejar debidamente el material. Se muestra particularmente que el campo seudo-magnético inducido por el campo de tensión planar no puede emerger de una teoría cuántica de campos en espacios curvos (abordaje top-down), sino de un análisis detallado del hamiltoniano tight-binding de los electrones pi en el grafeno (abordaje bottom-up).
Doctorat en Sciences
info:eu-repo/semantics/nonPublished