نتایج جستجو برای: variable ecological components

تعداد نتایج: 729860  

2004
J. W. Hurley R. W. Meier Herbert Hoover

2. A SMIDGEON ABOUT PROBABILITY AND EVENTS Wisdom ofttimes consists of knowing what to do next. – Herbert Hoover DEFINITIONS Experiment – any action or process that generates observations (e.g. flipping a coin) Trial – a single instance of an experiment (one flip of the coin) Outcome – the observation resulting from a trial (“heads”) Sample Space – the set of all possible outcomes of an experim...

Journal: :caspian journal of mathematical sciences 2014
m. h. rahmani doust f. haghighifar

some scientists are interesting to study in area of harvested ecological modelling. the harvested population dynamics is more realistic than other ecological models. in the present paper, some of the lotka-volterra predator-prey models have been considered. in the said models, existing species are harvested by constant or variable growth rates. the behavior of their solutions has been analyzed ...

ژورنال: طلوع بهداشت یزد 2020

   Introduction: Human ecology examines the interactions between humans and the environment. Investigation of the human happiness and health requires a systematic study of the human life and ecosystem, which includes the physical and social environment of the human species.  Ecosystem is the basis of changes that occur in the biological, psychological, and social systems, because they happen in...

2014
Tom Loney Nico J Nagelkerke

The validity of ecological studies in epidemiology for inferring causal relationships has been widely challenged as observed associations could be biased by the Ecological Fallacy. We reconsider the important design components of ecological studies, and discuss the conditions that may lead to spurious associations. Ecological associations are useful and valid when the ecological exposures can b...

2014
Tom Loney Nico J Nagelkerke

The validity of ecological studies in epidemiology for inferring causal relationships has been widely challenged as observed associations could be biased by the Ecological Fallacy. We reconsider the important design components of ecological studies, and discuss the conditions that may lead to spurious associations. Ecological associations are useful and valid when the ecological exposures can b...

تجلی, علی‌اکبر, میرآزادی, زهرا, پیله‌ور, بابک,

Due to the side effects of chemical drugs, special attention is given recently to pharmaceutical plants. Myrtle (Myrtus communis L.) is one of the valuable pharmaceutical plants, which is distributed over the vast areas of Iran. Yield and components of essential oil of this plant is dependent on ecological and genetic factors. In order to describe some ecological factors that affect myrtle in L...

2003
NICHOLAS J. GOTELLI

We analyzed a simple genetic model of ecological character displacement in a fluctuating environment. Character states of two identical, competing species were determined by a single-gene, two-allele model. In each generation, the carrying capacity of different segments of a uniform resource spectrum fluctuated randomly. Interand intraspecific exploitation competition reduced litnesses of simil...

Context is a vague notion with numerous building blocks making language test scores inferences quite convoluted. This study has made use of a model of item responding that has striven to theorize the contextual infrastructure of differential item functioning (DIF) research and help specify the sources of DIF. Two steps were taken in this research: first, to identify DIF by gender grouping via l...

Some scientists are interesting to study in area of harvested ecological modelling. The harvested population dynamics is more realistic than other ecological models. In the present paper, some of the Lotka-Volterra predator-prey models have been considered. In the said models, existing species are harvested by constant or variable growth rates. The behavior of their solutions has been analyzed ...

2015
Daniel E Schindler Jonathan B Armstrong Thomas E Reed

© The Ecological Society of America www.frontiersinecology.org T greatest challenges in ecology and evolution are in understanding how physical and biological processes that play out over extensive spatial, temporal, and taxonomic scales interact to affect the dynamics of genes, phenotypes, populations, and ecosystems. The fact that many biological properties are “scale-dependent” has been reco...

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