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Results 301 - 350 of 957
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Kauserud Håvard - - 2010
Most macrofungi produce ephemeral fruit bodies during autumn but some have adapted to spring fruiting. In this study, temporal changes in the time of spring fruiting in Norway and the UK during 1960-2007 have been investigated by statistical analyses of about 6000 herbarium and field records, covering 34 species. Nearly ...
Sosenski Paula - - 2010
Although the 6 magnitude and pattern of correlation among floral traits (phenotypic integration) is usually conceived as an adaptation for successful pollination and reproduction, studies on the evolution of plant reproductive systems have generally focused on one or a few characters. If evolutionary transitions between reproductive systems involve morphological floral ...
Verschuren Dirk - - 2009
External climate forcings-such as long-term changes in solar insolation-generate different climate responses in tropical and high latitude regions. Documenting the spatial and temporal variability of past climates is therefore critical for understanding how such forcings are translated into regional climate variability. In contrast to the data-rich middle and high latitudes, ...
Munga Stephen - - 2009
Spatial and temporal variations in the distribution of anopheline larval habitats and land use and land cover (LULC) changes can influence malaria transmission intensity. This information is important for understanding the environmental determinants of malaria transmission heterogeneity, and it is critical to the study of the effects of environmental changes ...
Lee Patricia N - - 2009
The Hawaiian bobtail squid, Euprymna scolopes, is a cephalopod whose small size, short lifespan, rapid growth, and year-round availability make it suitable as a model organism. E. scolopes is studied in three principal contexts: (1) as a model of cephalopod development; (2) as a model of animal-bacterial symbioses; and (3) ...
Hern?ndez Baeza Ana - - 2009
In this study, we evaluate the role of leader charisma in fostering positive affective team climate and preventing negative affective climate. The analysis of a longitudinal database of 137 bank branches by means of hierarchical moderated regression shows that leader charisma has a stronger effect on team optimism than on ...
Benesh Daniel P - - 2010
The timing of habitat switching in organisms with complex life cycles is an important life history characteristic that is often influenced by the larval growth environment. Under starvation, longer developmental times are frequently observed, probably as a consequence of developmental thresholds, but prolonged ontogeny sometimes also occurs under good conditions, ...
Llewelyn John - - 2010
Cane toads (Bufo marinus) are now moving about 5 times faster through tropical Australia than they did a half-century ago, during the early phases of toad invasion. Radio-tracking has revealed higher daily rates of displacement by toads at the invasion front compared to those from long-colonised areas: toads from frontal ...
Ebert Daniel - - 2009
The visual pigments of fish are thought to be adapted to the variable spectral qualities of aquatic light environments. Most research on the role of natural selection on the evolution of rhodopsins and dim-light vision in fish has focused on variation among species and higher taxa. In this issue, Larmuseau ...
Ripmeester Erwin A P - - 2010
Song plays an important role in avian communication and acoustic variation is important at both the individual and population level. Habitat-related variation between populations in particular can reflect adaptations to the environment accumulated over generations, but this may not always be the case. In this study, we test whether variation ...
Fullard James H - - 2010
The auditory thresholds of the AN2 interneuron and the behavioural thresholds of the anti-bat flight-steering responses that this cell evokes are less sensitive in female Pacific field crickets that live where bats have never existed (Moorea) compared with individuals subjected to intense levels of bat predation (Australia). In contrast, the ...
Martin Paul R - - 2010
Latitudinal variation in patterns of evolution has fascinated biologists for over a century, but our understanding of latitudinal differences in evolutionary processes-such as selection and drift-remains limited. Here, we test for, and find, accelerated evolution of color patterns in bird taxa that breed at higher latitudes compared with those breeding ...
Schmid-Hempel Paul - - 2009
To Darwin, parasites were fascinating examples of adaptation but their significance as selective factors for a wide range of phenomena has only been studied in depth over the last few decades. This work has had its roots in behavioural/evolutionary ecology on the one hand, and in population biology/ecology on the ...
Anderson Jill T - - 2010
In heterogeneous landscapes, divergent selection can favor the evolution of locally adapted ecotypes, especially when interhabitat gene flow is minimal. However, if habitats differ in size or quality, source-sink dynamics can shape evolutionary trajectories. Upland and bottomland forests of the southeastern USA differ in water table depth, light availability, edaphic ...
Piotrowicz Katarzyna - - 2009
Progressive global warming exerts strong influence on the lives and on the health of urban residents, many of who are weather sensitive people (meteoropaths). In the temperate zone, air temperature changes largely determine the seasonal oscillation of morbidity and mortality frequency. The present study analyzes the influence of air temperature ...
Mess A M - - 2009
A recent phylogenetic analysis achieved good resolution between the 5 suborders of rodent. As a novel finding it suggested a basal split that gave rise to a monophyletic group comprising Hystricomorpha and Sciuromorpha. We asked whether the new tree could cast light on the evolution of the interhaemal barrier in ...
Drysdale R N - - 2009
Variations in the intensity of high-latitude Northern Hemisphere summer insolation, driven largely by precession of the equinoxes, are widely thought to control the timing of Late Pleistocene glacial terminations. However, recently it has been suggested that changes in Earth's obliquity may be a more important mechanism. We present a new ...
Chakrabarti C G - - 2010
In the present paper, we have first studied the role of the maximum-entropy principle to explain the concept of organization of a physical system in the decreasing law of entropy with the increase of external constraints imposed on the system. We have then considered an open ecosystem (living) and determined ...
Martindale Mark Q - - 2009
Progress in resolving the phylogenetic relationships among animals and the expansion of molecular developmental studies to a broader variety of organisms has provided important insights into the evolution of developmental programs. These new studies make it possible to reevaluate old hypotheses about the evolution of animal body plans and to ...
Smith Silvia E - - 2009
In The Aleutian and Commander Islands and Their Inhabitants (Philadelphia: Wistar Institute of Anatomy and Biology, 1945), Hrdlicka proposed a population replacement event in the Aleutian Islands approximately 1,000 years ago based on a perceived temporal shift in cranial morphology. However, the archaeological record indicates cultural, and presumed population, continuity ...
Collins Sin??ad - - 2009
We investigate how different rates of environmental change affect adaptive outcomes and dynamics by selecting Chlamydomonas populations for over 200 generations in environments where the rate of change varies. We find that slower rates of environmental change result in end populations that grow faster and pay a lower cost of ...
Kim Hye-Mi - - 2009
Two distinctly different forms of tropical Pacific Ocean warming are shown to have substantially different impacts on the frequency and tracks of North Atlantic tropical cyclones. The eastern Pacific warming (EPW) is identical to that of the conventional El Niño, whereas the central Pacific warming (CPW) has maximum temperature anomalies ...
Roe John H - - 2009
Inter-wetland connectivity, defined here as the movement of biota among discrete water bodies, can have important population- and community-level consequences in aquatic systems. We examined inter-wetland connectivity in a southeastern Australian national park by intensively monitoring the movements of freshwater turtles (Chelodina longicollis) via capture-mark-recapture over a three-year period, and ...
Derryberry Elizabeth P - - 2009
Ecological variation appears to underlie the evolution of mating signals in many taxa, yet understanding of how this process occurs over time is limited. Here, I investigate whether changes over time in a well-studied mating signal-birdsong-are attributable to ecological factors that affect signal production and transmission. Variation in the acoustic ...
McGoey Brechann V - - 2009
Shade avoidance syndrome is a known adaptive response for Impatiens capensis growing in dense intraspecific competition. However, I. capensis also grow with dominant interspecific competitors in marshes. Here, we compare the I. capensis shade-avoidance phenotypes produced in the absence and presence of heterospecific competitors, as well as selection on those ...
Harder Lawrence D - - 2009
Although not 'a professed botanist', Charles Darwin made seminal contributions to understanding of floral and inflorescence function while seeking evidence of adaptation by natural selection. This review considers the legacy of Darwin's ideas from three perspectives. First, we examine the process of floral and inflorescence adaptation by surveying studies of ...
Mitchell Amir - - 2009
Natural habitats of some microorganisms may fluctuate erratically, whereas others, which are more predictable, offer the opportunity to prepare in advance for the next environmental change. In analogy to classical Pavlovian conditioning, microorganisms may have evolved to anticipate environmental stimuli by adapting to their temporal order of appearance. Here we ...
Petrocelli John V - - 2009
Punitive responses to crime have been linked to a relatively low need for cognition (NFC). Sargent's (2004) findings suggest that this relationship is due to a relatively complex attributional system, employed by high-NFC individuals, which permits them to recognize potential external or situational causes of crime. However, high-NFC individuals may ...
Colson-Proch C?line - - 2009
Subterranean environments are characterized by the quasi absence of thermal variations (+/-1 degrees C within a year), and organisms living in these biotopes for several millions of years, such as hypogean crustaceans, can be expected to have adapted to this very stable habitat. As hypogean organisms experience minimal thermal variation ...
Breukelaar A W - - 2009
Downstream migration of Anguilla anguilla silver eels was studied in the Lower Rhine, Germany, and the Rhine Delta, The Netherlands, in 2004-2006. Fish (n = 457) released near Cologne with implanted transponders were tracked by remote telemetry at 12 fixed detection locations distributed along the different possible migration routes to ...
Galloway Laura F - - 2009
Plants exhibit plasticity in response to their current environment and, in some cases, to that of the previous generation (i.e. maternal effects). However, few studies have evaluated both within- and between-generation plasticities and the extent to which they interact to influence fitness, especially in natural environments. The plasticity of adult ...
Bolnick Daniel I - - 2009
Adaptive divergence between adjoining populations reflects a balance between the diversifying effect of divergent selection and the potentially homogenizing effect of gene flow. In most models of migration-selection balance, gene flow is assumed to reflect individuals' inherent capacity to disperse, without regard to the match between individuals' phenotypes and the ...
Nilsson Anna L K - - 2009
The hormone corticosterone (CORT) is an important component of a bird's response to environmental stress, but it can also have negative effects. Therefore, birds on migration are hypothesized to have repressed stress responses (migration-modulation hypothesis). In contrast to earlier studies on long-distance migrants, we evaluate this hypothesis in a population ...
Schaefer Joerg M - - 2009
Understanding the timings of interhemispheric climate changes during the Holocene, along with their causes, remains a major problem of climate science. Here, we present a high-resolution 10Be chronology of glacier fluctuations in New Zealand's Southern Alps over the past 7000 years, including at least five events during the last millennium. ...
Lilleng Hallvard - - 2009
OBJECTIVES: To investigate seasonal variation of migraine headache in a population residing in an extreme Arctic locale. BACKGROUND: Exposure to light may trigger migraine attacks and patients may also be hypersensitive to light between the attacks. In previous studies of migraine in Northern latitudes we have demonstrated that patients with ...
Michimae Hirofumi - - 2009
Maternal effects are widespread and influence a variety of traits, for example, life history strategies, mate choice, and capacity to avoid predation. Therefore, maternal effects may also influence phenotypic plasticity of offspring, but few studies have addressed the relationship between maternal effects and phenotypic plasticity of offspring. We examined the ...
Møller A P - - 2009
Prey use their locomotory capacity to escape predators, and there should thus be strong viability selection on locomotory morphology of prey. We compared feather morphology of wood pigeons Columba palumbus killed by goshawks Accipiter gentilis with that of survivors to quantify directional and quadratic selection on primary and rectrix feathers. ...
Cunha C - - 2009
Hybridization, ploidy level and genomic constitution may be important to respond to different environments, by producing different phenotypes and thus reducing competitive interaction. Through geometric morphometrics, we examined variation in body size and shape among biotypes of the Squalius alburnoides hybrid complex and their sperm donor (Squalius carolitertii). Results showed ...
Delarue Julien - - 2009
Western Arctic bowhead whales (Balaena mysticetus) transit through the Chukchi Sea in spring and fall during their seasonal migration between their winter grounds in the Bering Sea and their summer feeding grounds in the Beaufort Sea, where their presence is well documented. Comparatively little is known about their use of ...
Gregersen F - - 2009
Sibling-size variation (SSV), estimated as the coefficient of variation of egg size, was investigated for 13 populations of brown trout Salmo trutta. SSV was negatively correlated with mean egg size both at the population and individual levels. After correction for the effect of mean egg size, SSV was also negatively ...
Anderson Kirk E - - 2009
In insect societies, worker versus queen development (reproductive caste) is typically governed by environmental factors, but some Pogonomyrmex seed-harvester ants exhibit strict genetic caste determination, resulting in an obligate mutualism between two reproductively isolated lineages. Queens mate randomly with multiple males from each lineage and intralineage crosses produce new queens, ...
Boothroyd, Gregory Stephen
This thesis explores the notion of site as a generative basis for architecture. Site is conceived not only as a plot of land where a building is located, but also as something that is the result of agency: the architectural intervention. Site is thus constructed with architecture; it is as ...
Zhang Zhibin - - 2009
Global warming is currently of great concern. Yet the ecological effects of low-frequency climate variations remain largely unknown. Recent analyses of interdecadal variability in population abundance of the Oriental migratory locust (Locusta migratoria manilensis) in China have revealed negative associations with temperature and positive associations with Yangtze drought and flood ...
Zhang Yiqun - - 2009
Nanocoils and straight nanoribbons have been controllably fabricated through the interfacial organization of an anthracene derivative. A morphology-dependent photoswitching has been observed. While the nanocoils show no photocurrent response, the straight nanoribbons display a switchable photocurrent upon an on/off illumination.
DiMichele W A - - 2009
The late Paleozoic earth experienced alternation between glacial and non-glacial climates at multiple temporal scales, accompanied by atmospheric CO2 fluctuations and global warming intervals, often attended by significant vegetational changes in equatorial latitudes of Pangaea. We assess the nature of climate-vegetation interaction during two time intervals: middle-late Pennsylvanian transition and ...
Endler John A - - 2009
Apostatic (frequency- or density-dependent) selection, aposematic signals, and mate choice behavior generally require that the mean prey or potential mate density m value be high enough (above a threshold T) to result in sufficient encounter rates for the searcher to learn or retain the association between conspicuous signals and prey ...
Powell S - - 2009
Caste evolution is a central process in the adaptive diversification of insect superorganisms. Nevertheless, how ecology shapes adaptive caste evolution remains poorly understood. Recent work with the ant genus Cephalotes has provided new comparative evidence that ecological specialization may drive adaptive caste specialization. Here, three key predictions of this adaptive ...
Pequegnat, Willis E
At present we have little evidence that successional changes following predictable patterns occur among epifaunal communities living on natural rock-reefs in the shallow sublittoral of. the open ocean. If this phenomenon does occur here, it can be detected by sustained observations at a single study site. In the period from ...
Lea Mary-Anne - - 2009
Since 1975, northern fur seal (Callorhinus ursinus) numbers at the Pribilof Islands (PI) in the Bering Sea have declined rapidly for unknown reasons. Migratory dispersal and habitat choice may affect first-year survivorship, thereby contributing to this decline. We compared migratory behaviour of 166 naive pups during 2 years from islands ...
Thompson, Matthew P.
Graduation date: 2009
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