نتایج جستجو برای: have variable ecosystems

تعداد نتایج: 3135311  

2016
Fanfeng Meng Xuan Dong Tao Hu Shuang Chang Jianhua Fan Peng Zhao Zhizhong Cui

BACKGROUND As a typical retrovirus, the evolution of Avian leukosis virus subgroup J (ALV-J) in different infectious ecosystems is not characterized, what we know is there are a cloud of diverse variants, namely quasispecies with considerable genetic diversity. This study is to explore the selection of infectious ecosystems on dominant variants and their evolutionary dynamics of ALV-J between D...

2015
Tal Polak James E. M. Watson Richard A. Fuller Liana N. Joseph Tara G. Martin Hugh P. Possingham Oscar Venter Josie Carwardine

The Convention on Biological Diversity (CBD)'s strategic plan advocates the use of environmental surrogates, such as ecosystems, as a basis for planning where new protected areas should be placed. However, the efficiency and effectiveness of this ecosystem-based planning approach to adequately capture threatened species in protected area networks is unknown. We tested the application of this ap...

2012
Shannon M. Murphy Gina M. Wimp Danny Lewis Robert F. Denno

Anthropogenic nutrient inputs into native ecosystems cause fluctuations in resources that normally limit plant growth, which has important consequences for associated food webs. Such inputs from agricultural and urban habitats into nearby natural systems are increasing globally and can be highly variable, spanning the range from sporadic to continuous. Despite the global increase in anthropogen...

2006
MELODY J. BERNOT JENNIFER L. TANK TODD V. ROYER

1. Agriculture is a major contributor of non-point source pollution to surface waters in the midwestern United States, resulting in eutrophication of freshwater aquatic ecosystems and development of hypoxia in the Gulf of Mexico. Agriculturally influenced streams are diverse in morphology and have variable nutrient concentrations. Understanding how nutrients are transformed and retained within ...

2014
Ellen Aartun Jan Hartvigsen Niels Wedderkopp Lise Hestbaek

BACKGROUND The severity and course of spinal pain is poorly understood in adolescents. The study aimed to determine the prevalence and two-year incidence, as well as the course, frequency, and intensity of pain in the neck, mid back, and low back (spinal pain). METHODS This study was a school-based prospective cohort study. All 5th and 6th grade students (11-13 years) at 14 schools in the Reg...

Journal: :Archives of pediatrics & adolescent medicine 2011
Megan A Moreno Fred Furtner Frederick P Rivara

S ometimes when a child is sick or hurt, it is necessary for physicians to do a procedure. The purpose of some procedures is to get more medical information; examples include doing a blood draw using a needle or collecting urine through a plastic tube called a catheter that goes into your child’s urethra. The purpose of other procedures is for a treatment, such as putting in stitches for a cut ...

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