Environmental variation

Xem 1-20 trên 67 kết quả Environmental variation
  • Tuyển tập các báo cáo nghiên cứu về sinh học được đăng trên tạp chí sinh học Journal of Biology đề tài: The pattern of genetic and environmental variation in relation to ageing in laying hens

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  • Have students think about where they are likely to see litter in the community. Have them think of ways they could educate other students about the problems associated with litter. Divide students into groups of three or four. Have the groups create an environmental awareness poster to be displayed inside the school. If possible, allow the students to decide where the poster should be hung, so that it is likely to be seen by the most students. Next, give each group a map of the school and the...

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  • Whereas the mechanical performance of plant organs has often been discussed in evolutionary biology [1,2], tree biomechanics has rarely been considered in the context of functional ecology. Functional ecology aims at understanding the functions of organisms that result in fluxes of biomass or energy within an ecosystem, e.g., a forest. This discipline studies the processes controlling these fluxes, at either the scale of an individual, community, or ecosystem, with their response to natural or anthropic environmental variations....

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  • Over the past several years, scientists, public health officials, and policy makers have become increasingly interested in understanding how the emergence and spread of infectious diseases could be affected by environmental factors, particularly variations in climate. In September 1995 the Institute of Medicine/ National Academy of Sciences and the National Science and Technology Council held a Conference on Human Health and Global Climate Change.

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  • This book challenges the conventional wisdom that natural resource wealth promotes autocracy. Oil and other forms of mineral wealth can promote both authoritarianism and democracy, the book argues, but they do so through different mechanisms; an understanding of these different mechanisms can help elucidate when either the authoritarian or democratic effects of resource wealth will be relatively strong.

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  • From the close of World War II until sometime in the middle of the 1960s two grand ideals ruled the architectural profession. One was a political faith in the vision of modernity – the meliorist belief that by affecting social change and imposing a universal environmental order architects could improve the human lot and repair a globe wrought by physical and moral devastation. The second was the belief that the most efficient way to achieve this amelioration was through technology and its application.

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  • SECTION I ECOLOGY OF INDIVIDUAL INSECTS THE INDIVIDUAL ORGANISM IS A FUNDAMENTAL unit of ecology. Organisms interact with their environment and affect ecosystem processes largely through their cumulative physiological and behavioral responses to environmental variation. Individual success in finding and using necessary habitats and resources to gain reproductive advantage determines fitness.

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  • Genetics is the science of genes, heredity, and the variation of organisms.[37][38] Genes encode the information necessary for synthesizing proteins, which in turn play a large role in influencing (though, in many instances, not completely determining) the final phenotype of the organism. In modern research, genetics provides important tools in the investigation of the function of a particular gene, or the analysis of genetic interactions. Within organisms, genetic information generally is carried in chromosomes, where it is represented in the chemical structure of particular DNA molecules....

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  • Understanding the forces that influence natural variation within and among populations has been a major objective of evolutionary biology for decades (Csilléry et al., 2010). It can be problematic, as natural populations may have complex demographic histories: size and range changes over time can lead to bottlenecks, fusions and expansions that leave signatures on the genetic composition of the population (Avise, 2004). Detection and analysis of genetic diversity can help us to understand the molecular basis of various biological phenomena in these natural systems.

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  • Normal cells are cohesive in nature but exfoliated when they attain maturation. During malignant conditions or during infection, the exfoliation becomes exaggerated and the epithelial cells show variation in morphology. Such exfoliated cells, when collected and appropriately stained, give information on the living epithelium from which they are derived. These characteristic cellular and nuclear appearances in cells thrown off from healthy epithelium, differ distinctly from those, derived from inflamed or malignant lesions.

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  • Tham khảo sách 'ecosystem management adaptive, community-based conservation', khoa học tự nhiên, công nghệ sinh học phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả

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  • In a neutral temperature environment, the metabolic rate of humans produces more heat than is necessary to maintain the core body temperature at 37°C.A normal body temperature is ordinarily maintained, despite environmental variations, because the hypothalamic thermoregulatory center balances the excess heat production derived from metabolic activity in muscle and the liver with heat dissipation from the skin and lungs.

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  • In order to support building engineering physicists in practice, we must develop new centres in universities and new funding mechanisms to support original and applied research into building energy performance. The dissemination of real world building performance information capable of being benchmarked, rather than marketing misinformation will not just inform future low carbon building designs, but also allow for the development of robust national policy.

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  • The Blacksmith Institute’s database contains almost 350 sites contaminated with mercury, putting close to 10 million people at risk from the identified sites. It is the second most prevalent pollutant in the database. The top sources of mercury pollution are artisanal gold processing, mining and ore processing, coal mining, processing and localized air pollution related to coal combustion at poorly controlled sites, and chemical manufacturing, notably for older chlor-alkali plants making chlorine. Artisanal mining of gold ores and processing using mercury is common worldwide.

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  • The world is changing quickly, and our models of learning, communicating, and acting must change accordingly. Throughout society we must rethink basic notions of how we define and accomplish our goals in a complex and changing environment, including how we prepare ourselves for professional careers. This book is an effort in that direction for students in natural resource management. It is a response to some of the challenges we perceive students will face in the early twenty-first century, and it is a practice field on which they may begin to develop their skills....

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  • Evolutionary biology and ecology share the goals of describing variation in natural systems and discovering its functional basis. Within this common framework, evolutionary biologists emphasize historical and lineage-dependent processes and hence often incorporate phylogenetic reconstructions and genetic models in their analyses. Ecologists, while cognizant of historical processes, tend to explain variation in terms of the contemporary effects of biotic and abiotic environmental factors.

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  • Guidelines are never intended to supersede profes- sional judgment; rather, they may be viewed as a relative constraint on individual clinician discretion in a particu- lar clinical circumstance. Less frequent variation in prac- tice is expected for a strong recommendation than might be expected with a recommendation. Options offer the most opportunity for practice variability. 30 Clinicians should always act and decide in a way that they believe will best serve their patients’ interests and needs, regard- less of guideline recommendations.

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  • Nonideal Transistor Behavior – High Field Effects • Mobility Degradation • Velocity Saturation – Channel Length Modulation – Threshold Voltage Effects • Body Effect • Drain-Induced Barrier Lowering • Short Channel Effect – Leakage • Subthreshold Leakage • Gate Leakage • Junction Leakage Process and Environmental Variations .Ideal Transistor I-V Shockley long-channel transistor models

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  • Health care providers are well placed to detect, treat, and prevent environmentally-related diseases and health conditions. Few mechanisms and structures are in place to enhance the recognition of environmental influences on human health, serve as repositories and sources of information for those concerned about children’s health and the environment, and promote action towards healthier and safer environments for children of today and adults of the future.

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  • Variation exists in the current evidence base with regard to the optimum RMI I threshold that should be applied in secondary care. The cut-off levels used will have implications for both the management options considered and the number of women who will be referred for specialist treatment. Therefore it is important to establish the relative sensitivities and specificities at the different levels. The research should be a prospective observational cohort study evaluating women referred with suspected ovarian cancer.

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