نتایج جستجو برای: seasonal availability

تعداد نتایج: 208251  

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2012
Jeffrey Shaman Alicia Karspeck

Influenza recurs seasonally in temperate regions of the world; however, our ability to predict the timing, duration, and magnitude of local seasonal outbreaks of influenza remains limited. Here we develop a framework for initializing real-time forecasts of seasonal influenza outbreaks, using a data assimilation technique commonly applied in numerical weather prediction. The availability of real...

Journal: :Mathematical biosciences 2010
M Otero H G Solari

We present a stochastic dynamical model for the transmission of dengue that takes into account seasonal and spatial dynamics of the vector Aedes aegypti. It describes disease dynamics triggered by the arrival of infected people in a city. We show that the probability of an epidemic outbreak depends on seasonal variation in temperature and on the availability of breeding sites. We also show that...

Journal: :Applied and environmental microbiology 1987
J Iriberri M Unanue I Barcina L Egea

The abundance and heterotrophic activity of attached and free-living bacteria were examined seasonally in coastal water. Heterotrophic activity was determined by the uptake of [C]glucose. The density of attached bacteria was always minor, not showing a seasonal variation, whereas the free-living bacteria were more numerous and showed a marked seasonal variation, their density being higher under...

Journal: :Environmental pollution 2006
Gerhard Wieser Vanessa C Luis Emilio Cuevas

Ozone uptake was studied in a pine forest in Tenerife, Canary Islands, an ecotone with strong seasonal changes in climate. Ambient ozone concentration showed a pronounced seasonal course with high concentrations during the dry and warm period and low concentrations during the wet and cold season. Ozone uptake by contrast showed no clear seasonal trend. This is because canopy conductance signifi...

Journal: :Global change biology 2013
Colin L Tucker Jennifer Bell Elise Pendall Kiona Ogle

Enhanced soil respiration in response to global warming may substantially increase atmospheric CO2 concentrations above the anthropogenic contribution, depending on the mechanisms underlying the temperature sensitivity of soil respiration. Here, we compared short-term and seasonal responses of soil respiration to a shifting thermal environment and variable substrate availability via laboratory ...

2007
Iain C. Field Corey J. A. Bradshaw Harry R. Burton Mark A. Hindell

Environmental conditions experienced in early life affect growth and influence life history strategies, especially in seasonal environments. We studied the seasonal and sexual variation in resource allocation in juvenile southern elephant seals to investigate whether they show a seasonal decline in growth. We also examined whether sexual differences in growth may lead to separate growth strateg...

Journal: :The Journal of animal ecology 2013
Kevin L Monteith Thomas R Stephenson Vernon C Bleich Mary M Conner Becky M Pierce R Terry Bowyer

Body reserves of numerous taxa follow seasonal rhythms that are a function of temporal patterns in food availability and life-history events; however, tests of the theory underlying the allocation of somatic reserves for long-lived organisms are rare, especially for free-ranging mammals. We evaluated the hypothesis that allocation of somatic reserves to survival (i.e., metabolic processes) and ...

Journal: :thrita 0
fatemeh toorang cancer research center, cancer institute of iran, tehran university of medical science, tehran, ir iran anahita houshiarrad department of nutrition research, national nutrition and food technology research institute, faculty of nutrition sciences and food technology, shahid beheshti university of medical sciences, tehran, ir iran; department of nutrition research, national nutrition and food technology research institute, faculty of nutrition sciences and food technology, shahid beheshti university of medical sciences, tehran, ir iran. tel: +98-9125507026 morteza abdollahi department of nutrition research, national nutrition and food technology research institute, faculty of nutrition sciences and food technology, shahid beheshti university of medical sciences, tehran, ir iran mina esmaili department of nutrition research, national nutrition and food technology research institute, faculty of nutrition sciences and food technology, shahid beheshti university of medical sciences, tehran, ir iran soraya ebrahimpour koujan department of nutrition, schools of health and nutrition, tabriz university of medical sciences, tabriz, ir iran

conclusions due to seasonal variations in fruit and vegetable dietary intakes, the interventional and case-control studies should consider seasonality. educational and price controlling programs may control such observed seasonality in the intake of fruit and vegetables. results the highest consumption of vegetables was seen in summer (289 ± 3.4 g/day) while the lowest was in winter (224 ± 3.2 ...

2015
Scott Davies Thomas Cros Damien Richard Simone L. Meddle Kazuyoshi Tsutsui Pierre Deviche

In many organisms, food availability is a proximate cue that synchronizes seasonal development of the reproductive system with optimal environmental conditions. Growth of the gonads and secondary sexual characteristics is orchestrated by the hypothalamic-pituitary-gonadal (HPG) axis. However, our understanding of the physiological mechanisms by which food availability modulates activity of the ...

2007
Rolf Borchert ROLF BORCHERT

Many trees of tropical dry forests flower or form new shoots soon after leaf shedding during the dry season, i.e., during a period when trees are likely to be severely water stressed. To resolve this apparent paradox, phenology and seasonal changes in tree water status were monitored during two consecutive dry seasons in > 150 trees of 37 species growing at different sites in the tropical dry l...

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