Pour voir les autres types de publications sur ce sujet consultez le lien suivant : Tree of Life, Boston (Mass.).
Articles de revues sur le sujet « Tree of Life, Boston (Mass.) »
Créez une référence correcte selon les styles APA, MLA, Chicago, Harvard et plusieurs autres
Consultez les 50 meilleurs articles de revues pour votre recherche sur le sujet « Tree of Life, Boston (Mass.) ».
À côté de chaque source dans la liste de références il y a un bouton « Ajouter à la bibliographie ». Cliquez sur ce bouton, et nous générerons automatiquement la référence bibliographique pour la source choisie selon votre style de citation préféré : APA, MLA, Harvard, Vancouver, Chicago, etc.
Vous pouvez aussi télécharger le texte intégral de la publication scolaire au format pdf et consulter son résumé en ligne lorsque ces informations sont inclues dans les métadonnées.
Parcourez les articles de revues sur diverses disciplines et organisez correctement votre bibliographie.
1
Akand, Elma H., et Kevin M. Downard. « Reimaging the Tree of Life Using a Mass Based Phylonumerics Approach ». Evolutionary Biology 47, no 1 (22 janvier 2020) : 76–84. http://dx.doi.org/10.1007/s11692-020-09490-1.
Texte intégral
2
Downard, Kevin M. « Darwin’s Tree of Life is Numbered. Resolving the Origins of Species by Mass ». Evolutionary Biology 47, no 4 (24 octobre 2020) : 325–33. http://dx.doi.org/10.1007/s11692-020-09517-7.
Texte intégral
3
Weemstra, Monique, Natasa Kiorapostolou, Jasper Ruijven, Liesje Mommer, Jorad Vries et Frank Sterck. « The role of fine‐root mass, specific root length and life span in tree performance : A whole‐tree exploration ». Functional Ecology 34, no 3 (5 février 2020) : 575–85. http://dx.doi.org/10.1111/1365-2435.13520.
Texte intégral
4
Connolly, James. « Bringing the City Back In : Space and Place in the Urban History of the Gilded Age and Progressive Era ». Journal of the Gilded Age and Progressive Era 1, no 3 (juillet 2002) : 258–78. http://dx.doi.org/10.1017/s1537781400000256.
Texte intégralRésumé :
Edward Bellamy's Looking Backward sought to understand the social consequences of industrialization by looking at a city. One of the Gilded Age's best-selling books, the Utopian novel magically transported lead character Julian West to a futuristic Boston set in the year 2000 and contrasted that ideal, cooperative world with the harsh reality of individualism-drenched, industrial Boston in 1887. Bellamy's vision of a twenty-first-century city was prescient about technology: it included automation, mass communication, and swift transportation. His social predictions proved less successful. Boston in the year 2000 was populated by Victorian ladies and gentlemen and lacked the cultural variety we associate with contemporary city life.
5
Pérez, Jonathan H., Daniel R. Ardia, Elise K. Chad et Ethan D. Clotfelter. « Experimental heating reveals nest temperature affects nestling condition in tree swallows ( Tachycineta bicolor ) ». Biology Letters 4, no 5 (15 juillet 2008) : 468–71. http://dx.doi.org/10.1098/rsbl.2008.0266.
Texte intégralRésumé :
Investment in one life-history stage can have delayed effects on subsequent life-history stages within a single reproductive bout. We experimentally heated tree swallow ( Tachycineta bicolor ) nests during incubation to test for effects on parental and nestling conditions. Females incubating in heated boxes maintained higher body condition and fed nestlings at higher rates. We cross-fostered nestlings and found that young nestlings (4–7 days old) incubated in heated nests had higher body condition and body mass, regardless of treatment status of their rearing parent. However, older nestlings which were fed by heated females maintained higher condition and body mass regardless of treatment status of their incubating parent. These results indicate that investment in one life-history stage can have multiple pathways of carry-over effects on future life-history stages.
6
Davies, T. Jonathan. « Losing history : how extinctions prune features from the tree of life ». Philosophical Transactions of the Royal Society B : Biological Sciences 370, no 1662 (19 février 2015) : 20140006. http://dx.doi.org/10.1098/rstb.2014.0006.
Texte intégralRésumé :
Biodiversity provides many valuable services to humanity; however, rapid expansion of the human population has placed increasing pressure on natural systems, and it has been suggested that we may be entering a sixth mass extinction. There is an urgent need, therefore, to prioritize conservation efforts if we are to maintain the provisioning of such service in the future. Phylogenetic diversity (PD), the summed branch lengths that connect species on the tree-of-life, might provide a valuable metric for conservation prioritization because it has been argued to capture feature diversity. Frequently, PD is estimated in millions of years, and therefore implicitly assumes an evolutionary model in which features diverge gradually over time. Here, I explore the expected loss of feature diversity when this assumption is violated. If evolution tends to slow down over time, as might be the case following adaptive radiations, losses of feature diversity might be relatively small. However, if evolution occurs in rapid bursts, following a punctuated model, impacts of extinctions might be much greater. PD captures many important properties, but if we use it as a proxy for feature diversity, we first need to ensure that we have the correct evolutionary model.
7
Read, Jennifer, Gordon D. Sanson, Tanguy Jaffré et Martin Burd. « Does tree size influence timing of flowering in Cerberiopsis candelabra (Apocynaceae), a long-lived monocarpic rain-forest tree ? » Journal of Tropical Ecology 22, no 6 (20 octobre 2006) : 621–29. http://dx.doi.org/10.1017/s0266467406003464.
Texte intégralRésumé :
Cerberiopsis candelabra is a long-lived monocarpic rain-forest tree endemic to New Caledonia that shows mass flowering across a substantial proportion of a population, and across a substantial number of populations. We investigated the relationship between tree size and flowering (and subsequent dying) across 18 populations from the flowering event of 2003 in order to understand the role of possible size thresholds for flowering in the life history and regeneration ecology of this monocarpic species. There was a strong positive correlation between trunk diameter and the incidence of flowering when population data were combined. However, the relationship between size and flowering was complex in that flowering occurred across a wide range of tree sizes, with almost complete overlap in size between flowering (5–79 cm dbh) and non-flowering trees (5–64 cm dbh), and with large trees in both the flowering and non-flowering state in the same population. In about half the populations studied there was no significant difference in mean trunk diameter of flowering and non-flowering trees. Nonetheless, we suggest that tree size may play a fundamental role in the life history and regeneration ecology of this species. The seedlings appear to be relatively shade-intolerant and dependent on large canopy gaps for recruitment. A significant effect of mass flowering and subsequent death of multiple large trees is the potential to form large canopy gaps and enhance seedling survival, as the gap is temporally linked with seed germination. However, it is unclear why there is such a large size range of flowering trees, i.e. whether this is just a consequence of the proximate cue, or whether the optimal size for flowering does indeed vary among individuals.
8
Haddad, Claudia Regina Baptista, Damiani Pereira Lemos et Paulo Mazzafera. « Leaf life span and nitrogen content in semideciduous forest tree species (Croton priscus and Hymenaea courbaril) ». Scientia Agricola 61, no 4 (2004) : 462–65. http://dx.doi.org/10.1590/s0103-90162004000400018.
Texte intégralRésumé :
In comparison to deciduous species, evergreen plants have lower leaf nutrient contents and higher leaf life span, important mechanisms for nutrient economy, allowing the colonization of low fertility soils. Strategies to conserve nitrogen in two semideciduous tropical forest tree species, with different leaf life spans were analyzed. The hypothesis was the fact that the two species would present different nitrogen conservation mechanisms in relation to chemical (total nitrogen, protein, chlorophyll, and proteolytic activity), functional (leaf life span, N-use efficiency, and N-resorption efficiency), morphological (specific leaf mass) leaf characteristics, and total nitrogen in the soil. Hymenaea courbaril L. presented lower nitrogen compounds in leaves, longer leaf life span, higher N-use efficiency, and higher specific leaf mass, while absorbing proportionally less nitrogen from the soil than Croton priscus Croizat. These characteristics can contribute for a better nitrogen economy strategy of H. courbaril. No relationship was found between leaf life span and N resorption efficiency, nor between leaf life span, protease activity and nitrogen mobilization. The electrophoretic profiles of proteolytic enzymes in young leaves of the two species presented more bands with enzymatic activity than other kinds of leaves.
9
Panyametheekul, Sirima, Thanakorn Rattanapun et Maneerat Ongwandee. « Ability of artificial and live houseplants to capture indoor particulate matter ». Indoor and Built Environment 27, no 1 (22 septembre 2016) : 121–28. http://dx.doi.org/10.1177/1420326x16671016.
Texte intégralRésumé :
Two artificial and three live houseplants were assessed for their abilities to capture particulate matter smaller than 2.5 µm (PM2.5) generated by burning an incense stick. The test plants included polyester Boston fern, polyethylene Dieffenbachia, Golden Pothos ( Epipremnum aureum), Painted nettle ( Plectranthus scutellarioides) and Rainbow tree ( Dracaena cincta Bak. ‘Tricolor’). Each plant was tested one at a time in a closed 8-m3 chamber, and the PM2.5 concentrations were continuously measured for 24 h. A loss rate constant for PM2.5 due to deposition onto leaf surface was determined by fitting measured concentrations to a mass balance model using nonlinear regression. The PM2.5 loss rates for the artificial Boston fern correlated well with its total leaf surface areas at the significant level of 0.5. All studied plants had PM2.5 loss rates ranging from 0.05 to 0.08 h−1 under the testing condition of similar total leaf surface areas, while a PM2.5 loss rate due to deposition onto the chamber surfaces was 0.03 h−1. Stereo microscope leaf images revealed the particle accumulation mostly on the midribs and veins rather than the flat blades, while the woven polyester fabric of the artificial plant acts as a filter for collecting the coarse particles.
10
Konjar, Matevž, Tom Levanič, Thomas Andrew Nagel et Milan Kobal. « Can we use dendrogeomorphology for the spatial and temporal analysis of less intensive mass movement processes ? : A case study of three debris flows in NW and W Slovenia ». Acta Silvae et Ligni 124 (2021) : 55–62. http://dx.doi.org/10.20315/asetl.124.5.
Texte intégralRésumé :
Debris flows can transport large amounts of material and therefore present a significant threat to infrastructure and human life. In this research, we used tree-ring width analyses to quantify the response of trees to three debris flow events in NW Slovenia (Javoršček, Srpenica) and W Slovenia (Nikova) for which we know the time of origin. We attempted to date these and similar tree responses in the past and compared the patterns between different tree species. Altogether, we sampled 147 trees across a range of tree species (Fagus sylvatica, Pinus sylvestris, Fraxinus excelsior, Fraxinus ornus, Acer pseudoplatanus, Picea abies, Juglans regia, Acer campestre, Tilia cordata and Ostrya carpinifolia), including reference trees that were outside the debris flow fan. For 91 trees, we constructed tree-ring chronologies and used pointer-year analysis to identify years that had abnormal growth. For the remaining trees (mostly Ostrya carpinifolia, Tilia cordata and Acer pseudoplatanus), we either could not accurately distinguish tree rings or two samples from a single tree showed significantly different growth patterns. The growth patterns of Fagus sylvatica and Picea abies following debris flow events showed a weak response at the Javoršček site and no clear responses at the other two sites. Tree species responded similarly at the same locations. Due to the lack of a clear response pattern, we were not able to reconstruct past debris flows.
11
Pettit, George R., Gordon M. Cragg, Judith Polonsky, Delbert L. Herald, Animesh Goswami, Cecil R. Smith, Christian Moretti, Jean M. Schmidt et David Weisleder. « Isolation and structure of rolliniastatin 1 from the South American tree Rolliniamucosa ». Canadian Journal of Chemistry 65, no 6 (1 juin 1987) : 1433–35. http://dx.doi.org/10.1139/v87-242.
Texte intégralRésumé :
Rolliniamucosa (Annonaceae), known in primitive medical practices of Indonesia and the West Indies as a treatment for tumors, has been investigated employing the seeds from a South American variety and the murine P388 lymphocytic leukemia (PS) for bioassay. The principal antineoplastic constituent (PS, 28% life extension, at 0.25 mg/kg and ED504.5 × 10−5 μg/mL) was found to be a new bis-tetrahydrofuran designated rolliniastatin 1. Structural elucidation of rolliniastatin 1 was accomplished by a combination of high resolution nuclear magnetic resonance (300 MHz), mass spectral, and X-ray crystal structure techniques.
12
Negi, G. C. S., et S. P. Singh. « Leaf nitrogen dynamics with particular reference to retranslocation in evergreen and deciduous tree species of Kumaun Himalaya ». Canadian Journal of Forest Research 23, no 3 (1 mars 1993) : 349–57. http://dx.doi.org/10.1139/x93-051.
Texte intégralRésumé :
The concentration and mass of nitrogen (N) were followed seasonally in leaves of 26 trees species of Central Himalaya: 11 evergreen species with about 1-year leaf life-span and 15 deciduous species. Like the deciduous species, the leaves of these evergreen species start senescing and losing mass in the year of formation. Species with higher N status retranslocated a larger proportion of leaf N prior to leaf abscission than the species with less favourable N status. The percentage of N mass in the leaf that was retranslocated during senescence ranged from 32.7 to 75.3%, but none of the species with N concentration less than 2.5% in mature leaves retranslocated more than 60% of N. Compared with evergreen species, on average the deciduous species showed higher N concentration in mature leaves (3.2 vs. 2.5%), higher proportion of leaf mass loss during senescence (31.6 vs. 26.2%), and greater proportion of retranslocated N mass from leaves (57.1 vs. 51.8%). With regard to the N-use efficiency the two groups of species were not clearly different. The dependence of deciduous species on retranslocated N mass for leaf growth during the dry period of the premonsoon season was greater than that of the evergreen species, which showed partial dependence on the soil N pool for new leaf formation.
13
Grant, Bruce. « Shrines and Sovereigns : Life, Death, and Religion in Rural Azerbaijan ». Comparative Studies in Society and History 53, no 3 (30 juin 2011) : 654–81. http://dx.doi.org/10.1017/s0010417511000284.
Texte intégralRésumé :
Shrines fill the Eurasian land mass. They can be found from Turkey in the west to China in the east, from the Arctic Circle in the north to Afghanistan in the south. Between town and country, they can consist of full-scale architectural complexes, or they may compose no more than an open field, a pile of stones, a tree, or a small mausoleum. They have been at the centers and peripheries of almost every major religious tradition of the region: Zoroastrianism, Judaism, Christianity, Islam, and Buddhism. Yet in the formerly socialist world, these places of pilgrimage have something even more in common: they were often cast as the last bastions of religious observance when churches, mosques, temples, and synagogues were sent crashing to the ground in rapid succession across the twentieth century.
14
Vitt, Laurie J. « Ecology and life history of the scansorial arboreal lizard Plica plica (Iguanidae) in Amazonian Brazil ». Canadian Journal of Zoology 69, no 2 (1 février 1991) : 504–11. http://dx.doi.org/10.1139/z91-077.
Texte intégralRésumé :
A field study on two populations of the tropical iguanid lizard Plica plica in the Brazilian Amazon revealed that this lowland forest species is diurnal, occurs on vertical smooth-barked trunks of the largest trees in the forest, and feeds mostly on ants. Comparisons between rainy season samples from Pará and dry season samples from Rondonia show that even though lizards ate, on average, the same number of prey, prey were larger in Rondonia and prey diversity was greater in Pará. Lizards sleep on tree trunks or similar surfaces when available, apparently leaving the trees only to deposit eggs. Clutches are deposited in palm litter and inside rotted palm trunks. Clutch size averages 2.9 ± 0.1 eggs and is significantly correlated with female snout–vent length. The reproductive season appears to be extended in that females produce at least two clutches. Relative clutch mass of females is low compared with that of other sit-and-wait foraging lizard species, and this, coupled with the flattened morphology, presumably reflects adaptations for maintaining the center of gravity near vertical smooth tree trunks.
15
Aris, Izzuddin M., Sheryl L. Rifas-Shiman, Ling-Jun Li, Ken P. Kleinman, Brent A. Coull, Diane R. Gold, Marie-France Hivert, Michael S. Kramer et Emily Oken. « Patterns of body mass index milestones in early life and cardiometabolic risk in early adolescence ». International Journal of Epidemiology 48, no 1 (8 janvier 2019) : 157–67. http://dx.doi.org/10.1093/ije/dyy286.
Texte intégralRésumé :
Abstract Background Few studies have examined the independent and combined relationships of body mass index (BMI) peak and rebound with adiposity, insulin resistance and metabolic risk later in life. We used data from Project Viva, a well-characterized birth cohort from Boston with repeated measures of BMI, to help fill this gap. Methods Among 1681 children with BMI data from birth to mid childhood, we fitted individual BMI trajectories using mixed-effects models with natural cubic splines and estimated age, and magnitude of BMI, at peak (in infancy) and rebound (in early childhood). We obtained cardiometabolic measures of the children in early adolescence (median 12.9 years) and analysed their associations with the BMI parameters. Results After adjusting for potential confounders, age and magnitude at infancy BMI peak were associated with greater adolescent adiposity, and earlier adiposity rebound was strongly associated with greater adiposity, insulin resistance and metabolic risk score independently of BMI peak. Children with a normal timing of BMI peak plus early rebound had an adverse cardiometabolic profile, characterized by higher fat mass index {β 2.2 kg/m2 [95% confidence interval (CI) 1.6, 2.9]}, trunk fat mass index [1.1 kg/m2 (0.8, 1.5)], insulin resistance [0.2 units (0.04, 0.4)] and metabolic risk score [0.4 units (0.2, 0.5)] compared with children with a normal BMI peak and a normal rebound pattern. Children without a BMI peak (no decline in BMI after the rise in infancy) also had adverse adolescent metabolic profiles. Conclusions Early age at BMI rebound is a strong risk factor for cardiometabolic risk, independent of BMI peak. Children with a normal peak-early rebound pattern, or without any BMI decline following infancy, are at greatest risk of adverse cardiometabolic profile in adolescence. Routine monitoring of BMI may help to identify children who are at greatest risk of developing an adverse cardiometabolic profile in later life and who may be targeted for preventive interventions.
16
Houlden, Kate, et Sorcha Gunne. « The Gendering of Irish and Caribbean Food/Land Crises in Children's Novels by Marita Conlon-McKenna and James Berry ». Irish University Review 49, no 1 (mai 2019) : 36–53. http://dx.doi.org/10.3366/iur.2019.0379.
Texte intégralRésumé :
Marita Conlan-McKenna's Under the Hawthorne Tree (1990) and James Berry's Ajeemah and His Son (1991) are children's novels that address foundational national or regional trauma (dealing with transatlantic slavery and the Irish potato famine respectively). Both employ historical fictive modes to bring the nineteenth century to life, in the process illustrating the extractive capitalism at the heart of the colonial endeavour. Links between Ireland and the Caribbean have long existed, Hilary Beckles observing the persistent characterization of the Irish as ‘one-dimensional colonial characters […] battered and bruised by a triumphant imperial Englishness that viewed them as “baggage” along the route from Cork and Limerick through Bristol to Boston and Barbados’ (Beckles ix). Expanding on this sense of Ireland and the Caribbean as jointly tethered to global imperial trends, this article focuses on the role of food and consumption, arguing that these novels make clear the ongoing role of food scarcity and land control within the cyclical crises of capitalist expansion. Ajeemah and His Son reinforces the importance of land ownership in Jamaica as its protagonist falls in line with the values of the society he has been thrust into, while Under the Hawthorne Tree frames famine as a representative crisis of the world-system.
17
Wheelwright, Nathaniel T., Joanna Leary et Caragh Fitzgerald. « The costs of reproduction in tree swallows (Tachycineta bicolor) ». Canadian Journal of Zoology 69, no 10 (1 octobre 1991) : 2540–47. http://dx.doi.org/10.1139/z91-358.
Texte intégralRésumé :
We investigated the effect of brood size on nestling growth and survival, parental survival, and future fecundity in tree swallows (Tachycineta bicolor) over a 4-year period (1987–1990) in an effort to understand whether reproductive trade-offs limit clutch size in birds. In addition to examining naturally varying brood sizes in a population on Kent Island, New Brunswick, Canada, we experimentally modified brood sizes, increasing or decreasing the reproductive burdens of females by two offspring. Unlike previous studies, broods of the same females were enlarged or reduced in up to 3 successive years in a search for evidence of cumulative costs of reproduction that might go undetected by a single brood manipulation. Neither observation nor experiment supported the existence of a trade-off between offspring quality and quantity, in contrast with the predictions of life-history theory. Nestling wing length, mass, and tarsus length were unrelated to brood size. Although differences between means were in the direction predicted, few differences were statistically significant, despite large sample sizes. Nestlings from small broods were no more likely to return as breeding adults than nestlings from large broods, but return rates of both groups were very low. Parental return rates were also independent of brood size, and there was no evidence of a negative effect of brood size on future fecundity (laying date, clutch size). Reproductive success, nestling size, and survival did not differ between treatments for females whose broods were manipulated in successive years. Within the range of brood sizes observed in this study, the life-history costs of feeding one or two additional nestlings in tree swallows appear to be slight and cannot explain observed clutch sizes. Costs not measured in this study, such as the production of eggs or postfledging parental care, may be more important in limiting clutch size in birds.
18
Fidgen, Jeffrey G., Mark C. Whitmore, Chris J. K. MacQuarrie et Jean J. Turgeon. « Detection of Adelges tsugae (Hemiptera : Adelgidae) wool using Velcro-covered balls ». Canadian Entomologist 153, no 5 (4 juin 2021) : 640–50. http://dx.doi.org/10.4039/tce.2021.24.
Texte intégralRésumé :
AbstractAdelges tsugae Annand (Hemiptera: Adelgidae), a nonindigenous insect pest of hemlock (Tsuga spp.) (Pinaceae) in eastern North America, spends most of its life cycle within an ovisac, which resembles a woolly white mass on twigs. We evaluated the probability of detecting adelgid wool with Velcro®-covered balls when taking an increasing number of samples per tree (field sampling) and number of trees per simulated stand. We examined the relationship between the detection of adelgid wool using this technique and the incidence of A. tsugae-infested twigs by sampling lower-crown branch tips of the same trees. We found that the probability of detecting wool with ball sampling increased with number of ball samples per tree, with number of trees per simulated stand, and with increasing incidence of ovisacs in the lower crown. When sampling an individual tree, we found that 20 ball samples per tree achieved a targeted precision level of 0.75, but when sampling a stand, we found that 10 ball samples per tree took the least time for the range of simulated A. tsugae infestations we tested. These sample sizes are recommended for detection of A. tsugae infestations on an individual tree and in a hemlock stand.
19
Flórez Leguía, María Katherinne, Paula Camila Riveros Calvete, Paulina Ojeda et Jorge Alberto Carrillo Bayona. « Germ Cell Tumor with Bronchial Fistula ». Case Reports in Radiology 2020 (29 février 2020) : 1–3. http://dx.doi.org/10.1155/2020/7650206.
Texte intégralRésumé :
Germ cell tumors account for 15% of anterior mediastinum tumors. Fistulas are abnormal communications between two surfaces covered by the epithelium. A fistula can occur between the bronchial tree and the adjacent anatomical structures secondary to variable etiologies. The main clinical manifestations of bronchial fistulas include hemoptysis, purulent cough, and pneumonia, which might threaten the patient’s life. Diagnosis can be established with computed tomography, which shows direct and indirect signs of a fistulous tract. We present the case of a 25-year-old patient, with an embryonic carcinoma of the mediastinum, who developed a fistula between the mediastinal mass and the bronchial tree after chemotherapy and thoracic radiotherapy. We carried out a review of the literature about the epidemiological aspects and the physiopathology and the relevant radiological findings of this pathology.
20
Pires, Claudio Rodrigues, Adriano Czapkowski, Edward Araujo Júnior et Sebastião Marques Zanforlin Filho. « Diagnosis of Intra-Abdominal Extralobar Pulmonary Sequestration by means of Ultrasound in a Neonate ». Case Reports in Pediatrics 2013 (2013) : 1–3. http://dx.doi.org/10.1155/2013/623102.
Texte intégralRésumé :
Pulmonary sequestration is a congenital abnormality consisting of a mass of pulmonary tissue that presents an abnormal connection with the tracheobronchial tree, with a blood supply coming from an anomalous artery derived from the systemic circulation. Extralobar pulmonary sequestration is characterized by having pleural coverings that are independent of the normal lungs, with vascular supply usually coming from the aorta or from one of its branches. This diagnosis can be suspected prenatally if an abdominal mass, generally below the diaphragm, is seen. Here, we present a case of a neonate on the second day of life, with ultrasonography showing extralobar pulmonary sequestration located above the left adrenal gland that prenatally simulated a neuroblastoma.
21
Shao, Zeguo, Yuhong Xiang, Yingchao Zhu, Aiqin Fan et Peng Zhang. « Influences of Daily Life Habits on Risk Factors of Stroke Based on Decision Tree and Correlation Matrix ». Computational and Mathematical Methods in Medicine 2020 (1 juin 2020) : 1–12. http://dx.doi.org/10.1155/2020/3217356.
Texte intégralRésumé :
Purpose. To explore the influences of smoking, alcohol consumption, drinking tea, diet, sleep, and exercise on the risk of stroke and relationships among the factors, present corresponding knowledge-based rules, and provide a scientific basis for assessment and intervention of risk factors of stroke. Methods. The decision tree C4.5 algorithm was optimized and utilized to establish a model for stroke risk assessment; then, the main risk factors of stroke (including hypertension, dyslipidemia, diabetes, atrial fibrillation, body mass index (BMI), history of stroke, family history of stroke, and transient ischemic attack (TIA)) and daily habits (e.g., smoking, alcohol consumption, drinking tea, diet, sleep, and exercise) were analyzed; corresponding knowledge-based rules were finally presented. Establish a correlation matrix of stroke risk factors and analyze the relationship between stroke risk factors. Results. The accuracy of the established model for stroke risk assessment was 87.53%, and the kappa coefficient was 0.8344, which was superior to that of the random forest and Logistic algorithm. Additionally, 37 knowledge-based rules that can be used for prevention of risk factors of stroke were derived and verified. According to in-depth analysis of risk factors of stroke, the values of smoking, exercise, sleep, drinking tea, alcohol consumption, and diet were 6.00, 7.00, 8.67, 9.33, 10.00, 10.60, and 10.75, respectively, indicating that their influence on risk factors of stroke was reduced in turn; on the one hand, smoking and exercise were strongly associated with other risk factors of stroke; on the other hand, sleep, drinking tea, alcohol consumption, and diet were not firmly associated with other risk factors of stroke, and they were relatively tightly associated with smoking and exercise. Conclusions. Establishment of a model for stroke risk assessment, analysis of factors influencing risk factors of stroke, analysis of relationships among those factors, and derivation of knowledge-based rules are helpful for prevention and treatment of stroke.
22
MCKENNA, DUANE D., ALEXANDER L. WILD, KOJUN KANDA, CHARLES L. BELLAMY, ROLF G. BEUTEL, MICHAEL S. CATERINO, CHARLES W. FARNUM et al. « The beetle tree of life reveals that C oleoptera survived end‐ P ermian mass extinction to diversify during the C retaceous terrestrial revolution ». Systematic Entomology 40, no 4 (6 juillet 2015) : 835–80. http://dx.doi.org/10.1111/syen.12132.
Texte intégral
23
Schultzhaus, Janna N., William Judson Hervey, Chris R. Taitt, Chris R. So, Dagmar H. Leary, Kathryn J. Wahl et Christopher M. Spillmann. « Comparative analysis of stalked and acorn barnacle adhesive proteomes ». Open Biology 11, no 8 (août 2021) : 210142. http://dx.doi.org/10.1098/rsob.210142.
Texte intégralRésumé :
Barnacles interest the scientific community for multiple reasons: their unique evolutionary trajectory, vast diversity and economic impact—as a harvested food source and also as one of the most prolific macroscopic hard biofouling organisms. A common, yet novel, trait among barnacles is adhesion, which has enabled a sessile adult existence and global colonization of the oceans. Barnacle adhesive is primarily composed of proteins, but knowledge of how the adhesive proteome varies across the tree of life is unknown due to a lack of genomic information. Here, we supplement previous mass spectrometry analyses of barnacle adhesive with recently sequenced genomes to compare the adhesive proteomes of Pollicipes pollicipes (Pedunculata) and Amphibalanus amphitrite (Sessilia). Although both species contain the same broad protein categories, we detail differences that exist between these species. The barnacle-unique cement proteins show the greatest difference between species, although these differences are diminished when amino acid composition and glycosylation potential are considered. By performing an in-depth comparison of the adhesive proteomes of these distantly related barnacle species, we show their similarities and provide a roadmap for future studies examining sequence-specific differences to identify the proteins responsible for functional differences across the barnacle tree of life.
24
Moore, Jonathan R., Arthur P. K. Argles, Kai Zhu, Chris Huntingford et Peter M. Cox. « Validation of demographic equilibrium theory against tree-size distributions and biomass density in Amazonia ». Biogeosciences 17, no 4 (26 février 2020) : 1013–32. http://dx.doi.org/10.5194/bg-17-1013-2020.
Texte intégralRésumé :
Abstract. Predicting the response of forests to climate and land-use change depends on models that can simulate the time-varying distribution of different tree sizes within a forest – so-called forest demography models. A necessary condition for such models to be trustworthy is that they can reproduce the tree-size distributions that are observed within existing forests worldwide. In a previous study, we showed that demographic equilibrium theory (DET) is able to fit tree-diameter distributions for forests across North America, using a single site-specific fitting parameter (μ) which represents the ratio of the rate of mortality to growth for a tree of a reference size. We use a form of DET that assumes tree-size profiles are in a steady state resulting from the balance between a size-independent rate of tree mortality and tree growth rates that vary as a power law of tree size (as measured by either trunk diameter or biomass). In this study, we test DET against ForestPlots data for 124 sites across Amazonia, fitting, using maximum likelihood estimation, to both directly measured trunk diameter data and also biomass estimates derived from published allometric relationships. Again, we find that DET fits the observed tree-size distributions well, with best-fit values of the exponent relating growth rate to tree mass giving a mean of ϕ=0.71 (0.31 for trunk diameter). This finding is broadly consistent with exponents of ϕ=0.75 (ϕ=1/3 for trunk diameter) predicted by metabolic scaling theory (MST) allometry. The fitted ϕ and μ parameters also show a clear relationship that is suggestive of life-history trade-offs. When we fix to the MST value of ϕ=0.75, we find that best-fit values of μ cluster around 0.25 for trunk diameter, which is similar to the best-fit value we found for North America of 0.22. This suggests an as yet unexplained preferred ratio of mortality to growth across forests of very different types and locations.
25
Turner, R. Eugene, et Erick M. Swenson. « The Life and Death and Consequences of Canals and Spoil Banks in Salt Marshes ». Wetlands 40, no 6 (7 septembre 2020) : 1957–65. http://dx.doi.org/10.1007/s13157-020-01354-w.
Texte intégralRésumé :
AbstractWe describe the consequence and demise of levees (spoil banks) built from dredging canals in Louisiana salt marshes using morphometric measurements made over 30 years, soil collections on the spoil bank and in the salt marshes behind, and complementary observations from other areas. These measurements were used to determine the temporal bounds of how long spoil banks last and if salt marsh soils remaining in salt marshes are affected. If the rates of changes in spoil bank morphology continue, then the estimated life time of the shrub-tree vegetation at a representative spoil bank is 81 years, the spoil bank width is 89 years, and the dredged channel will erode to the center of the spoil bank after 118 years. The soils in marshes behind the spoil bank have a higher bulk density than in reference marshes, accumulate more mineral matter per year, have lower root mass and are weaker. These observations are compatible with measurements of spoil bank width, vegetative cover and soil compaction, and the conversion from wetland to open water on a coastwide scale.
26
Patrut, Adrian, Diana H. Mayne, Karl F. von Reden, Daniel A. Lowy, Sarah Venter, Ann P. McNichol, Mark L. Roberts et Dragos Margineanu. « Age and Growth Rate Dynamics of an Old African Baobab Determined by Radiocarbon Dating ». Radiocarbon 52, no 2 (2010) : 727–34. http://dx.doi.org/10.1017/s0033822200045744.
Texte intégralRésumé :
In 2008, a large African baobab (Adansonia digitata L.) from Makulu Makete, South Africa, split vertically into 2 sections, revealing a large enclosed cavity. Several wood samples collected from the cavity were processed and radiocarbon dated by accelerator mass spectrometry (AMS) for determining the age and growth rate dynamics of the tree. The 14C date of the oldest sample was found to be of 1016 ± 22 BP, which corresponds to a calibrated age of 1000 ± 15 yr. Thus, the Makulu Makete tree, which eventually collapsed to the ground and died, becomes the second oldest African baobab dated accurately to at least 1000 yr. The conventional growth rate of the trunk, estimated by the radial increase, declined gradually over its life cycle. However, the growth rate expressed more adequately by the cross-sectional area increase and by the volume increase accelerated up to the age of 650 yr and remained almost constant over the past 450 yr.
27
Glushko, S. G., I. R. Galiullin et N. B. Prokhorenko. « Implementation of tree species strategy during progressive successions ». FORESTRY BULLETIN 25, no 1 (février 2021) : 5–12. http://dx.doi.org/10.18698/2542-1468-2021-1-5-12.
Texte intégralRésumé :
On the example of regeneration succession in forests, the features of silvicultural properties of the main forest-forming species growing in oak forests of the Middle Volga region are considered. The conclusion is made about the predominance of pioneer-serial forest communities formed by pioneer species in the study area. The pioneer species, which differ significantly in their silvicultural properties from the so-called «primary forest species», are predominant in modern forests. It is shown that at the later stages of reforestation successions, pioneer-serial forest communities are of great importance, the productivity of which becomes stable. The incomplete nature of progressive successions in the surveyed forests was revealed. To restore primary forests, a set of additional measures is required to facilitate the forests reconstruction and the entire forest fund of the region. The mass destruction of forests influences the processes of forest growing conditions and it is determined as a topical issue for further study. The connection between changes in the main forest species and forest communities and changes in forest growing conditions has been established. It is indicated that deforestation massively destroys the biotic environment and alters environmental processes, being the reason for silvicultural properties change in forest plants and their communities. The development of silvicultural properties is adaptive, in this regard, deforestation, with massive destruction of the biotic environment and a corresponding change in environmental processes, contributes to the devlopment of properties inherent in pioneer-serial forest communities. With the degradation of primary forests, a change in the main forest species and forest communities that make up modern forests is noted. Many silvicultural properties inherent in primary forests are not developed in modern conditions. Instead of primary forests, secondary forests are spread, derivative, with other silvicultural properties and their mdevelopment in the form of a complex characteristic of behavior or life strategy. The properties manifested by forest communities and individual species need to be generalized for further research. We have proposed to combine all the properties of forests into the concept of information potential. The information potential of forests can be used to study the features of the silvicultural properties in a changing natural environment.
28
McCarty, John P. « Variation in Growth of Nestling Tree Swallows Across Multiple Temporal and Spatial Scales ». Auk 118, no 1 (1 janvier 2001) : 176–90. http://dx.doi.org/10.1093/auk/118.1.176.
Texte intégralRésumé :
AbstractDifferences within a species in rates of growth of nestlings can be used as indicators of the quality of parental care, environmental conditions, and future success of offspring, whereas comparisons among different species may reflect a history of different ecological conditions or life-history strategies. The presesnt study examines the patterns of variation in growth in nestling Tree Swallows (Tachycineta bicolor) from across the species' range and compares Tree Swallows to other species. Growth of Tree Swallows was typical of other species in the family Hirundinidae. As a family, the Hirundinidae have slower growth than typical for passerines. Growth rate of species of Hirundinidae was not correlated with adult body mass or average brood size. Contrary to predictions, species that are double-brooded did not have higher growth rates, but swallow species living at higher latitudes did have higher growth rates than tropical species. Substantial variation in growth rates was observed among populations of Tree Swallows, yet the amount of variation observed between breeding colonies only a few kilometers apart, or from the same colony in different years, was as great as that seen in populations separated by hundreds of kilometers. Within a population, differences in growth among years were correlated with temperature and food supply when nestlings were being raised. No correlation between climate and growth was seen when comparing different populations. Differences between populations were not explained by local habitat, nor were large-scale geographic patterns evident. I used both experimental and observational evidence to evaluate the implications of short-term reduction in growth for subsequent growth and survival. Nestlings were slow to recover from even very short periods of delayed growth that occur early in the nestling phase. Return of nestlings with experimentally or naturally induced delayed growth was reduced, which suggests that short interruptions in growth may have long term effects on postfledging survival, even though mass at fledging is not affected.
29
Choi, Joon-Il, Chandana Lall, Puneet Bhargava et David K. Imagawa. « Giant Choledochal Cyst Mimicking Massive Gallbladder Hydrops in an Adult Patient : Multi Detector Computed Tomography and Magnetic Resonance Imaging Findings Correlated to Gross and Histopathological Findings ». Journal of Clinical Imaging Science 3 (29 octobre 2013) : 45. http://dx.doi.org/10.4103/2156-7514.120785.
Texte intégralRésumé :
Choledochal cysts are uncommon congenital anomalies of the biliary tree, commonly presenting in infancy, generally in the 1st year of life. Presentation in adult life is less common, accounting for 20% of cases. A 19-year-old female patient presented to the Emergency Department with severe abdominal distension, a palpable abdominal mass, mild jaundice and low grade fever. Ultrasound, computed tomography (CT) and magnetic resonance imaging of the abdomen showed a massive septated cystic lesion filling the entire abdomen with a significant mass effect on surrounding structures. Origin of the lesion was unclear and diagnosis included a giant mesenteric or duplication cyst, massive gallbladder with hydrops, biliary cystadenoma and giant choledochal cyst, among others. Final diagnosis was a Type IA choledochal cyst with massive asymmetric cystic dilatation of the extra-hepatic segments of the left hepatic duct with asymmetric dilatation of the right hepatic duct. Patient had an uneventful recovery after resection of the entire extrahepatic cyst and Roux-en-Y hepaticojejunostomy at the level of the hilum. In this article, we correlate CT and MRI findings to gross and histopathological findings of this giant Todani's Type IA choledochal cyst.
30
Osunkoya, Olusegun O., Dahliayana Bujang, Huzaimi Moksin, Franz L. Wimmer et Thippeswamy M. Holige. « Leaf properties and construction costs of common, co-occurring plant species of disturbed heath forest in Borneo ». Australian Journal of Botany 52, no 4 (2004) : 499. http://dx.doi.org/10.1071/bt04018.
Texte intégralRésumé :
The leaf properties and construction costs (CC) are reported for eight indigenous heath (kerangas)-forest species and three invasive (exotic) species of Acacia. Both groups of species co-occur and colonise disturbed lowland tropical heath-rainforest habitats in Brunei, Borneo Island. Across species, CC mass-based increased with nitrogen (N) and heat of combustion (HC), and decreased with ash content. CC area-based showed similar trends (although weaker in strength) in addition to significant positive correlation with leaf mass per unit area (LMA). Within the native species, the CCs of the shrub and small tree species were lower and significantly different from those of medium-sized tree species. Given the invasive success of the three acacias, it is hypothesised that these species may require less energy for biomass construction than do the native species. Within similar life growth form, no difference in CC mass-based was detected between the native trees and the invasive acacias. For CC area-based, the invasive Acacia species had a higher value. These findings failed to uphold our hypothesis. LMA and leaf N and phosphorus (P), but not potassium (K), were higher in the invasive acacias. The higher N and LMA could have been the cause of higher CC area-based in the invasive acacias. From the ordination of 11 species on the basis of leaf properties, the invasive and native species are more likely to be found in different groupings—although some native species seem more affiliated with the invasive than with their own guild, especially Alphitonia and Macaranga.
31
Göth, Ann, et Christopher S. Evans. « Egg size predicts motor performance and postnatal weight gain of Australian Brush-turkey (Alectura lathami) hatchlings ». Canadian Journal of Zoology 82, no 6 (1 juin 2004) : 972–79. http://dx.doi.org/10.1139/z04-070.
Texte intégralRésumé :
Birds usually influence offspring survival through the amount of parental care they provide. Megapodes have evolved a different life history. Eggs are incubated by external heat sources, and chicks dig themselves out of their underground nest and live independently of their parents. Egg size is one of the few means by which females can influence chick survival. We found that in the Australian Brush-turkey, Alectura lathami Gray, 1831, eggs and hatchlings varied considerably in size, with a ratio of 1.62 between the largest and the smallest egg. Egg size was positively correlated with hatchling body mass and tarsus length. It also significantly predicted the chicks' motor performance: chicks from larger eggs dug their way out of their underground nest faster and were more active when kept in a resting box and monitored by motion detection software. The main advantage of reaching the surface more quickly is likely that such chicks will have more time to find suitable food, refuge, and a tree for roosting at night while still feeding on their internal yolk reserves. Egg size also interacted significantly with body mass during the first 10 months of life. A size advantage at hatching thus seems to have an immediate effect on motor performance and a longer term effect on the ability to gain mass.
32
Janis, Jaclyn A., Sheryl L. Rifas-Shiman, Shravanthi M. Seshasayee, Sharon Sagiv, Antonia M. Calafat, Diane R. Gold, Brent A. Coull, Clifford J. Rosen, Emily Oken et Abby F. Fleisch. « Plasma Concentrations of Per- and Polyfluoroalkyl Substances and Body Composition From Mid-Childhood to Early Adolescence ». Journal of Clinical Endocrinology & ; Metabolism 106, no 9 (19 mars 2021) : e3760-e3770. http://dx.doi.org/10.1210/clinem/dgab187.
Texte intégralRésumé :
Abstract Context Per- and polyfluoroalkyl substances (PFAS) may alter body composition by lowering anabolic hormones and increasing inflammation, but data are limited, particularly in adolescence when body composition is rapidly changing. Objective To evaluate associations of PFAS plasma concentrations in childhood with change in body composition through early adolescence. Methods A total of 537 children in the Boston-area Project Viva cohort participated in this study. We used multivariable linear regression and Bayesian kernel machine regression (BKMR) to examine associations of plasma concentrations of 6 PFAS, quantified by mass spectrometry, in mid-childhood (mean age, 7.9 years; 2007-2010) with change in body composition measured by dual-energy x-ray absorptiometry from mid-childhood to early adolescence (mean age, 13.1 years). Results In single-PFAS linear regression models, children with higher concentrations of perfluorooctanoate (PFOA), perfluorooctane sulfonate (PFOS), perfluorodecanoate (PFDA), and perfluorohexane sulfonate (PFHxS) had less accrual of lean mass (eg, −0.33 [95% CI: −0.52, −0.13] kg/m2 per doubling of PFOA). Children with higher PFOS and PFHxS had less accrual of total and truncal fat mass (eg, −0.32 [95% CI: −0.54, −0.11] kg/m2 total fat mass per doubling of PFOS), particularly subcutaneous fat mass (eg, −17.26 [95% CI −32.25, −2.27] g/m2 per doubling of PFOS). Children with higher PFDA and perfluorononanoate (PFNA) had greater accrual of visceral fat mass (eg, 0.44 [95% CI: 0.13, 0.75] g/m2 per doubling of PFDA). Results from BKMR mixture models were consistent with linear regression analyses. Conclusion Early life exposure to some but not all PFAS may be associated with adverse changes in body composition.
33
NASCIMENTO, Marcelo Τ., et John PROCTOR. « Leaf herbivory on three tree species in a monodominant and two other Terra firme forests on Maracá Island, Brazil ». Acta Amazonica 31, no 1 (mars 2001) : 27. http://dx.doi.org/10.1590/1809-43922001311038.
Texte intégralRésumé :
The aim of this study was to test the hypothesis that the monodominant non-pioneer Peltogyne gracilipes, typically does not suffer density-dependent herbivory (Janzen-Connell model). Two components of intraspecific variation in leaf herbivory were measured: 1) the variation between individuals in the population at the same time and 2) the temporal variation in rates of damage to each individual. The study was carried out on Maracá Island, Roraima, Brazil in three plots (50 m χ 50 m) in each of three forest types: Peltogyne-rich forest (PRF), Peltogyne-poor forest (PPF), and forest without Peltogyne (FWP). Two other non-pioneer species (Ecclinusa guianensis and Pradosia surinamensis) were chosen for comparison because they were fairly abundant and their seedlings could be readily identified. The values of leaf area removed by herbivores of trees and seedlings of the three study species were in the range reported for other tropical tree species (2-16%, standing damage). There were no differences within species between forests. However, there was a significant difference among species but this was not correlated with seedling density. Peltogyne seedlings showed no evidence of density-dependent herbivory as predicted by the Janzen-Connell model despite the fact that adult trees were observed to suffer a mass defoliation in April 1992. This result suggests that Peltogyne may be dominant partly due to escape from herbivory in the early stages of its life although it may suffer occasional mass defoliation as an adult.
34
Arcila, Dahiana, et James C. Tyler. « Mass extinction in tetraodontiform fishes linked to the Palaeocene–Eocene thermal maximum ». Proceedings of the Royal Society B : Biological Sciences 284, no 1866 (8 novembre 2017) : 20171771. http://dx.doi.org/10.1098/rspb.2017.1771.
Texte intégralRésumé :
Integrative evolutionary analyses based upon fossil and extant species provide a powerful approach for understanding past diversification events and for assessing the tempo of evolution across the Tree of Life. Herein, we demonstrate the importance of integrating fossil and extant species for inferring patterns of lineage diversification that would otherwise be masked in analyses that examine only one source of evidence. We infer the phylogeny and macroevolutionary history of the Tetraodontiformes (triggerfishes, pufferfishes and allies), a group with one of the most extensive fossil records among fishes. Our analyses combine molecular and morphological data, based on an expanded matrix that adds newly coded fossil species and character states. Beyond confidently resolving the relationships and divergence times of tetraodontiforms, our diversification analyses detect a major mass-extinction event during the Palaeocene–Eocene Thermal Maximum (PETM), followed by a marked increase in speciation rates. This pattern is consistently obtained when fossil and extant species are integrated, whereas examination of the fossil occurrences alone failed to detect major diversification changes during the PETM. When taking into account non-homogeneous models, our analyses also detect a rapid lineage diversification increase in one of the groups (tetraodontoids) during the middle Miocene, which is considered a key period in the evolution of reef fishes associated with trophic changes and ecological opportunity. In summary, our analyses show distinct diversification dynamics estimated from phylogenies and the fossil record, suggesting that different episodes shaped the evolution of tetraodontiforms during the Cenozoic.
35
Marthews, Toby R., Christopher E. Mullins, James W. Dalling et David F. R. P. Burslem. « Burial and secondary dispersal of small seeds in a tropical forest ». Journal of Tropical Ecology 24, no 6 (novembre 2008) : 595–605. http://dx.doi.org/10.1017/s026646740800535x.
Texte intégralRésumé :
Abstract:Secondary dispersal is an important stage in the life cycle of tree species, determining the fate of a high proportion of all seeds. For small-seeded species both physical and biological processes may influence the secondary fate of seeds, however the relative importance of these processes is not well known. Seeds of the pioneer tree species Cecropia insignis (seed mass 0.5 mg), Trema micrantha (2.5 mg) and Apeiba aspera (14.2 mg) and five types of artificial seed were sown in understorey, treefall-gap and large-gap sites on Barro Colorado Island, Panama, during the wet season of 2005. Sowing areas were excavated after periods up to 26 d and cores divided into depths of 0–5, 5–10, 10–20 and 20–50 mm to allow high-resolution estimation of the rate and amount of burial and displacement of seeds. Over 26 d, 2.8% of artificial seeds were buried to a mean depth of 10.5 mm below the soil surface and 43.9% of unburied seeds displaced laterally >5 cm. Significantly more (87.9% and 80.9%) seeds of Cecropia insignis and Trema micrantha were displaced than artificial seeds of similar mass, size and density. A generalised linear model suggested that burial mostly occurred within 15 d, while displacement occurred continuously up to 26 d. The dominant cause of displacement and burial was probably rainfall, while seed removal by ants may also have contributed to displacement.
36
Boddy, Amy M., Lisa M. Abegglen, Allan P. Pessier, Athena Aktipis, Joshua D. Schiffman, Carlo C. Maley et Carmel Witte. « Lifetime cancer prevalence and life history traits in mammals ». Evolution, Medicine, and Public Health 2020, no 1 (1 janvier 2020) : 187–95. http://dx.doi.org/10.1093/emph/eoaa015.
Texte intégralRésumé :
Abstract Background Cancer is a common diagnosis in many mammalian species, yet they vary in their vulnerability to cancer. The factors driving this variation are unknown, but life history theory offers potential explanations to why cancer defense mechanisms are not equal across species. Methodology Here we report the prevalence of neoplasia and malignancy in 37 mammalian species, representing 11 mammalian orders, using 42 years of well curated necropsy data from the San Diego Zoo and San Diego Zoo Safari Park. We collected data on life history components of these species and tested for associations between life history traits and both neoplasia and malignancy, while controlling for phylogenetic history. Results These results support Peto’s paradox, in that we find no association between lifespan and/or body mass and the prevalence of neoplasia or malignancy. However, a positive relationship exists between litter size and prevalence of malignancy (P = 0.005, Adj. R2 = 0.212), suggesting that a species’ life history strategy may influence cancer vulnerabilities. Lastly, we tested for the relationship between placental invasiveness and malignancy. We find no evidence for an association between placental depth and malignancy prevalence (P = 0.618, Adj. R2 = 0.068). Conclusions Life history theory offers a powerful framework to understand variation in cancer defenses across the tree of life. These findings provide insight into the relationship between life history traits and cancer vulnerabilities, which suggest a trade-off between reproduction and cancer defenses. Lay summary Why are some mammals more vulnerable to cancer than others? We test whether life history trade-offs may explain this variation in cancer risk. Bigger, longer-lived animals do not develop more cancer compared to smaller, shorter-lived animals. However, we find a positive association between litter size and cancer prevalence in mammals.
37
Hart, D. G. « Christianity and Civil Society : Theological Education for Public Life. Edited by Rodney L. Petersen. Maryknoll, N.Y. and Cambridge, Mass. : Orbis Books and Boston Theological Institute, 1995. 165 pp. $16.95 ». Journal of Church and State 39, no 2 (1 mars 1997) : 371. http://dx.doi.org/10.1093/jcs/39.2.371.
Texte intégral
38
INTACHAT, JURIE, JEREMY D. HOLLOWAY et HARRY STAINES. « Effects of weather and phenology on the abundance and diversity of geometroid moths in a natural Malaysian tropical rain forest ». Journal of Tropical Ecology 17, no 3 (27 avril 2001) : 411–29. http://dx.doi.org/10.1017/s0266467401001286.
Texte intégralRésumé :
Geometroid moth abundance, species richness, weather and plant phenology were monitored monthly for 3 y in the lowland dipterocarp forest at Pasoh Forest Reserve, Negeri Sembilan in Malaysia. The intensity of tree flowering in the previous month (with mass events triggered in response to El Niño Southern Oscillations) was an important environmental factor positively correlated with the numbers of species and individuals of geometroid moths that emerge in any month. Abundance for geometroid moths was greater in months with high flowering and flushing in the previous month but low flowering in the month before that. Important weather parameters that influenced moth abundance were monthly rainfall, relative humidity and minimum temperature in previous months. High rainfall 3 mo previously led to an increase in moth abundance (perhaps by stimulating an increase in fresh plant material), whereas high rainfall and relative humidity thereafter served to decrease abundance, possibly by encouraging the spread and activity of pathogens: all these factors impacted on early life-stage survivorship. Similar trends were observed for individual geometroid families and subfamilies. The diversity measurement for the geometroid moths, α from the log-series, was correlated more with weather parameters than with tree phenology.
39
Souza, Luiz Guilherme Meira de, Ricardo Fernandes de Souza et Raimundo Vicente Pereira Neto. « Obtaining, characterizing and applying a Composite with Polyester Resin and Carnauba Leaf Petioles Powder ». Research, Society and Development 9, no 9 (31 août 2020) : e601997445. http://dx.doi.org/10.33448/rsd-v9i9.7445.
Texte intégralRésumé :
The carnauba, the tree of life, is a palm tree found in all regions of Brazil and has many applications, from electronics to cosmetics, with a greater emphasis on wax. The objective of this research was to obtain composites using petioles fibers from carnauba leaves and polyester resin. The powder was obtained using forage grinding and subsequent sieving, generating residues with different grain sizes. All the obtained granulometries were tested and the smaller one was chosen, due to its greater viability to obtain the composite, due to its better processability. Three mass proportions of the mixture between matrix and residues were chosen, 5%, 7.5% and 10%, since above that percentage there was a compromise in the processability and obtaining the composite studied. Mechanical, thermal and environmental characterizations were performed, which demonstrated the feasibility of the proposed composite. The carnauba powder was present in the composite as fill charge. The best formulation, 10%, was chosen to make a parabola of a solar cooker at concentration to produce cooking food. The composite can also be used in the manufacture of decorative panels for the support of televisions, as well as in the manufacture of furniture.
40
Chiu, Christine C., Christopher I. Keeling et Joerg Bohlmann. « Monoterpenyl esters in juvenile mountain pine beetle and sex-specific release of the aggregation pheromone trans-verbenol ». Proceedings of the National Academy of Sciences 115, no 14 (19 mars 2018) : 3652–57. http://dx.doi.org/10.1073/pnas.1722380115.
Texte intégralRésumé :
A recent outbreak of mountain pine beetle (MPB) has spread over more than 25 million hectares of pine forests in western North America, affecting pine species of sensitive boreal and mountain ecosystems. During initial host colonization, female MPB produce and release the aggregation pheromone trans-verbenol to coordinate a mass attack of individual trees. trans-Verbenol is formed by hydroxylation of α-pinene, a monoterpene of the pine oleoresin defense. It is thought that adult females produce and immediately release trans-verbenol when encountering α-pinene on a new host tree. Here, we show that both sexes of MPB accumulate the monoterpenyl esters verbenyl oleate and verbenyl palmitate during their development in the brood tree. Verbenyl oleate and verbenyl palmitate were retained in adult female MPB until the time of emergence from brood trees, but were depleted in males. Adult females released trans-verbenol in response to treatment with juvenile hormone III (JHIII). While both sexes produced verbenyl esters when exposed to α-pinene, only females responded to JHIII with release of trans-verbenol. Accumulation of verbenyl esters at earlier life stages may allow adult females to release the aggregation pheromone trans-verbenol upon landing on a new host tree, independent of access to α-pinene. Formation of verbenyl esters may be part of a general detoxification system to overcome host monoterpene defenses in both sexes, from which a specialized and female-specific system of pheromone biosynthesis and release may have evolved.
41
Netherer, Sigrid, Dineshkumar Kandasamy, Anna Jirosová, Blanka Kalinová, Martin Schebeck et Fredrik Schlyter. « Interactions among Norway spruce, the bark beetle Ips typographus and its fungal symbionts in times of drought ». Journal of Pest Science 94, no 3 (22 février 2021) : 591–614. http://dx.doi.org/10.1007/s10340-021-01341-y.
Texte intégralRésumé :
AbstractResilience and functionality of European Norway spruce forests are increasingly threatened by mass outbreaks of the bark beetle Ips typographus promoted by heat, wind throw and drought. Here, we review current knowledge on Norway spruce and I. typographus interactions from the perspective of drought-stressed trees, host selection, colonisation behaviour of beetles, with multi-level effects of symbiotic ophiostomatoid fungi. By including chemo-ecological, molecular and behavioural perspectives, we provide a comprehensive picture on this complex, multitrophic system in the light of climate change. Trees invest carbon into specialised metabolism to produce defence compounds against biotic invaders; processes that are strongly affected by physiological stress such as drought. Spruce bark contains numerous terpenoid and phenolic substances, which are important for bark beetle aggregation and attack success. Abiotic stressors such as increased temperatures and drought affect composition, amounts and emission rates of volatile compounds. Thus, drought events may influence olfactory responses of I. typographus, and further the pheromone communication enabling mass attack. In addition, I. typographus is associated with numerous ophiostomatoid fungal symbionts with multiple effects on beetle life history. Symbiotic fungi degrade spruce toxins, help to exhaust tree defences, produce beetle semiochemicals, and possibly provide nutrition. As the various fungal associates have different temperature optima, they can influence the performance of I. typographus differently under changing environmental conditions. Finally, we discuss why effects of drought on tree-killing by bark beetles are still poorly understood and provide an outlook on future research on this eruptive species using both, field and laboratory experiments.
42
Kearney, Brian D., Phillip G. Byrne et Richard D. Reina. « Anuran developmental plasticity loss : the cost of constant salinity stress ». Australian Journal of Zoology 63, no 5 (2015) : 331. http://dx.doi.org/10.1071/zo15017.
Texte intégralRésumé :
In animals with a complex life cycle, changes in biotic and abiotic conditions during development can alter growth and maturation rates, causing carry-over effects in postmetamorphic phenotypes. In anurans, this developmental plasticity can result in a trade-off between length of larval period and body size at metamorphosis in stressful environments. Secondary salinisation has been identified as a substantial stressor to amphibians; however, little is known about how salinity-induced developmental plasticity differs between anuran populations. We examined differences in survival, time to metamorphosis, size at metamorphosis (mass and snout–vent length) and body condition at metamorphosis in response to elevated salinity in three populations of the brown tree frog (Litoria ewingii). Significant differences in size at metamorphosis between salinity treatments were observed in tadpoles sourced from freshwater wetlands and ephemeral wetlands, with tadpoles showing a reduced mass and snout–vent length at metamorphosis in the higher-salinity treatment. There were no significant differences in metamorphic traits between salinity treatments in tadpoles sourced from a consistently brackish wetland, suggesting either an erosion of developmental plasticity in response to elevated salinity, or the magnitude of salinity required to alter developmental traits is higher in this population. Our results indicate that environmental conditions of source populations need to be considered when studying life-history adaptations in response to environmental change.
43
Kurokawa, Hiroko, Toshiya Yoshida, Toshio Nakamura, Julaihi Lai et Tohru Nakashizuka. « The age of tropical rain-forest canopy species, Borneo ironwood (Eusideroxylon zwageri), determined by 14C dating ». Journal of Tropical Ecology 19, no 1 (janvier 2003) : 1–7. http://dx.doi.org/10.1017/s0266467403003018.
Texte intégralRésumé :
Using 14C dating, the life span and growth rate of Borneo ironwood (Eusideroxylon zwageri, Lauraceae), which is a canopy tree species with extremely durable and decay-resistant wood distributed in tropical rain forests of South-East Asia, were studied. Timber segments collected from 15 logged stumps in Kubah National Park, Sarawak, Malaysia, were analysed by accelerator mass spectrometry and the obtained data were calibrated to determine the age of individuals. The 14C dating turned out to be an effective method for estimating ages of long-lived trees, such as E. zwageri, in the aseasonal tropics because the estimated error was small compared with estimated age. We found that E. zwageri can live more than 1000 y and that the growth rate of this species was very slow, with a mean radial growth rate of 0·058 cm y-1. The life span was much greater and the growth rate was much slower than those observed or estimated for trees of Dipterocarpaceae, the dominant family in this tropical forest. The long life span of this species may be caused by wood durability with a high specific gravity and abundant defensive compounds. Given equal carbon allocation, the high density and carbon-based defensive compounds may result in a reduced growth rate.
44
Breen, Louise A. « Philip Cash. Dr. Benjamin Waterhouse : A Life in Medicine and Public Service (1754–1846). 516 pp., apps., index. Sagamore Beach, Mass. : Boston Medical Library and Science History Publications, 2006. $56 (cloth). » Isis 99, no 1 (mars 2008) : 192–93. http://dx.doi.org/10.1086/589370.
Texte intégral
45
Naef, Andreas P. « Claude E. Welch, A twentieth-century surgeon. My life in the Massachusetts General Hospital. Boston, Mass., Massachusetts General Hospital, 1992. XX, 392 S. Illustr. Portr. $ 24.95. ISBN 0-88135-181-4. » Gesnerus 50, no 3-4 (25 novembre 1993) : 303–4. http://dx.doi.org/10.1163/22977953-0500304036.
Texte intégral
46
Stenström, Kristina, Göran Skog, Charlotte Thornberg, Bengt Erlandsson, Ragnar Hellborg, Sören Mattsson et Per Persson. « 14C Levels in the Vicinity of Two Swedish Nuclear Power Plants and at Two “Clean-Air” Sites in Southernmost Sweden ». Radiocarbon 40, no 1 (1997) : 433–38. http://dx.doi.org/10.1017/s0033822200018312.
Texte intégralRésumé :
14C is one of the radionuclides that are produced to different degrees by neutron-induced reactions in all types of nuclear reactors. Part of the 14C created is continuously released into the surrounding environment during normal operation as airborne effluents in various chemical forms (such as CO2, CO and hydrocarbons) through the ventilation system of the plant. Because of the biological importance of carbon and the long half-life of 14C, it is of interest to measure the releases and their incorporation into living material. We report here on the 14C activity concentrations in annual tree rings and the air around two Swedish nuclear power plants, as well as the background 14C activity levels from two reference sites in southern Sweden from 1973–1996. We used both accelerator mass spectrometry (AMS) and decay counting in the investigation.
47
Cox, Amelia R., Raleigh J. Robertson, Ádám Z. Lendvai, Kennedy Everitt et Frances Bonier. « Rainy springs linked to poor nestling growth in a declining avian aerial insectivore ( Tachycineta bicolor ) ». Proceedings of the Royal Society B : Biological Sciences 286, no 1898 (13 mars 2019) : 20190018. http://dx.doi.org/10.1098/rspb.2019.0018.
Texte intégralRésumé :
As species shift their ranges and phenology to cope with climate change, many are left without a ready supply of their preferred food source during critical life stages. Food shortages are often assumed to be driven by reduced total food abundance, but here we propose that climate change may cause short-term food shortages for foraging specialists without affecting overall food availability. We frame this hypothesis around the special case of birds that forage on flying insects for whom effects mediated by their shared food resource have been proposed to cause avian aerial insectivores' decline worldwide. Flying insects are inactive during cold, wet or windy conditions, effectively reducing food availability to zero even if insect abundance remains otherwise unchanged. Using long-term monitoring data from a declining population of tree swallows ( Tachycineta bicolor ), we show that nestlings’ body mass declined substantially from 1977 to 2017. In 2017, nestlings had lower body mass if it rained during the preceding 3 days, though females increased provisioning rates, potentially in an attempt to compensate. Adult body mass, particularly that of the males, has also declined over the long-term study. Mean rainfall during the nestling period has increased by 9.3 ± 0.3 mm decade −1 , potentially explaining declining nestling body mass and population declines. Therefore, we suggest that reduced food availability, distinct from food abundance, may be an important and previously overlooked consequence of climate change, which could be affecting populations of species that specialize on foraging on flying insects.
48
Łukowski, Adrian, Marian J. Giertych, Dawid Adamczyk, Ewa Mąderek et Piotr Karolewski. « Preference and Performance of the Pine-Tree Lappet Dendrolimus pini on Various Pine Species ». Forests 12, no 9 (16 septembre 2021) : 1261. http://dx.doi.org/10.3390/f12091261.
Texte intégralRésumé :
Global commercial and recreational transport may lead to the unintentional invasion of insect species, which in turn may pose a threat to native organisms. In this study, we aimed to assess whether the economically important pest of Pinus sylvestris L., moth Dendrolimus pini L. (DP), is able to feed on nine other pine species, and how this will affect its survival, performance, growth, and development. We carried out food choice tests and a no-choice laboratory feeding experiment. We found that this insect mostly preferred its prime host, but also Pinus cembra L., Pinus contorta Douglas ex Loudon, Pinus nigra J.F.Arnold, and Pinus ponderosa Douglas ex C.Lawson. The performance test revealed a host-specific response of DP to the host plant. This response was manifested in a large variation in body mass as well as in a decrease or increase in life-history traits, such as fecundity, and wing morphology parameters. However, the larvae’s choice of particular hosts corresponded to the results of the performance test. Larvae more willingly selected food allowing better results in their performance. Larvae achieved better values of growth and development when fed on European and North American pine species or on species with two- and three-needle fascicles. In addition, attractants and repellents in needles of different pine species were chemically analyzed. Variations in the secondary metabolite composition as well as the specific leaf area of different pine species effectively explained the results found in the insects, but the content of sugars and nitrogen remains to be elucidated. We speculate that DP poses a serious threat to large areas of pine forests, if transferred, as it can survive and develop on many economically important tree species in North America and Europe.
49
Tenekecioglu, Erhan, et Mustafa Yılmaz. « A bronchogenic cyst with atrial flutter ». Asian Journal of Medical Sciences 5, no 4 (17 mai 2014) : 94–96. http://dx.doi.org/10.3126/ajms.v5i4.9695.
Texte intégralRésumé :
The majority of bronchogenic cysts occur in the mediastinum and especially within the pulmonary parenchyma. Bronchogenic cysts have various clinical and radiological manifestations. In adults, these are often asymptomatic and most of them are only incidentally recognized in imaging procedures. In infancy and early childhood, compression of the tracheobronchial tree leads to symptoms and occasionaly life-threatening complications. Bronchogenic cysts have been stated rarely among the causes of an arythmia in early childhood. We reported a 7-years old female presented with paroxysmal palpitation continuing for one month. Contrast enhanced computed tomography showed cystic mass in the right hemi-thorax, compressing the right atrium. After surgical removal histopathologic examination revealed a lining of respiratory epithelium associated with a wall containing smooth muscle, a finding that is characteristic of bronchogenic cyst. DOI: http://dx.doi.org/10.3126/ajms.v5i4.9695 Asian Journal of Medical Sciences 2014 Vol.5(4); 94-96
50
Arndt, Stefan K., Wolfgang Wanek, Günter Hoch, Andreas Richter et Marianne Popp. « Flexibility of nitrogen metabolism in the tropical C3crassulacean acid metabolism tree species Clusia minor ». Functional Plant Biology 29, no 6 (2002) : 741. http://dx.doi.org/10.1071/pp01207.
Texte intégralRésumé :
This paper originates from a presentation at the IIIrd International Congress on Crassulacean Acid Metabolism, Cape Tribulation, Queensland, Australia, August 2001. The C3-crassulacean acid metabolism tropical hemiepiphytic tree, Clusia minor L., is highly flexible in terms of ecological sites occupied, life forms, and photosynthetic and metabolic pathways. We studied nitrogen uptake patterns in two glasshouse 15N-labelling experiments using hydroponically-grown plants and excised roots of pot-grown C. minor, and investigated leaf and root nitrate reductase activity (NRA) in a field study in Venezuela. The results of both 15N-uptake experiments indicate that C. minor utilized all offered nitrogen sources, but clearly preferred to take up NH4+ over glycine (GLY) and NO3-. The uptake pattern of NH4+ and NO3- was identical in intact plants and excised roots, and NH4+ was taken up to a much larger extent in both experiments. Gas chromatography-mass spectrometry (GC-MS) analysis of amino acids in excised roots revealed that glutamine (45 atom-%), glutamate (23 atom-%) and alanine (34 atom-%) accounted for most of the labelled soluble amino acids after 2-h labelling with 15NH4+. High amounts of 15N in GLY and serine confirmed that GLY was taken up as an intact molecule and metabolized in the excised roots. With 15NO3- labelling, only a small amount of 15N was found in the amino acid fraction, indicating a low NO3- assimilation rate by nitrate reductase. This was confirmed by low NRA of leaves and roots in C. minor plants in Venezuela. It appears, therefore, that a high degree of plasticity is not reflected in nitrogen uptake and metabolism. Although C. minor exhibits clear preferences for NH4+ uptake, it can utilize other sources of nitrogen, and the nitrogen uptake pattern represents an adaptation to the natural environments in which C. minor can grow.