نتایج جستجو برای: visitation state
تعداد نتایج: 859170 فیلتر نتایج به سال:
While current studies on complex networks focus on systems that change relatively slowly in time, the structure of the most visited regions of the web is altered at the time scale from hours to days. Here we investigate the dynamics of visitation of a major news portal, representing the prototype for such a rapidly evolving network. The nodes of the network can be classified into stable nodes, ...
Ronda Drahozal is a staff nurse in the medical ICU in the Department of Nursing and Patient Care Services at the University of Iowa Hospitals and Clinics in Iowa City, Iowa. lead to deterioration in hemodynamic or intracranial pressure indices. Nurses, as patient advocates, desire to limit potentially detrimental stimuli. Studies have found a decrease or no significant change in heart rate, blo...
Pollinator-plant relationships are found to be particularly vulnerable to land use change. Yet despite extensive research in agricultural and natural systems, less attention has focused on these interactions in neighboring urban areas and its impact on pollination services. We investigated pollinator-plant interactions in a peri-urban landscape on the outskirts of the San Francisco Bay Area, Ca...
Abundance and visitation of pollinator assemblages tend to decrease with altitude, leading to an increase in pollen limitation. Thus increased competition for pollinators may generate stronger selection on attractive traits of flowers at high elevations and cause floral adaptive evolution. Few studies have related geographically variable selection from pollinators and intraspecific floral diffe...
There is growing concern that current pollinator decline will affect the reproduction of plant species, potentially driving a decline in plant population densities. We experimentally tested whether a reduction in flower visitation caused a reduction in fertilization rate in several species, and whether any reduction in fecundity of species depends on their degree of reproductive dependence on p...
Sustainable agricultural landscapes by definition provide high magnitude and stability of ecosystem services, biodiversity and crop productivity. However, few studies have considered landscape effects on the stability of ecosystem services. We tested whether isolation from florally diverse natural and semi-natural areas reduces the spatial and temporal stability of flower-visitor richness and p...
EXECUTIVE SUMMARY Evaluating the effectiveness of maternal and child home visitation programs can be challenging. The complexity of program models, coupled with considerations of real-world program implementation, requires thoughtful and flexible evaluation strategies. Yet, meaningful evaluations of home visitation programs are not only feasible, but are essential as policymakers demand stronge...
Pollinators serve critical roles for the functioning of terrestrial ecosystems, and have an estimated annual value of over $150 billion for global agriculture. Mounting evidence from agricultural systems reveals that pollinators are declining in many regions of the world, and with a lack of information on whether pollinator communities in natural systems are following similar trends, identifyin...
Modeling pollination ecosystem services requires a spatially explicit, process-based approach because they depend on both the behavioral responses of pollinators to the amount and spatial arrangement of habitat and on the within- and between-season dynamics of pollinator populations in response to land use. We describe a novel pollinator model predicting flower visitation rates by wild central-...
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