RESUMO
Pollinators foraging for food resources can be waylaid by mass-flowering plants located in their foraging pathway in landscapes. The waylaying effect of pollinators is often studied at a single spatial scale; to date, little is known about the best spatial extent at which waylaying effect of pollinators can be measured. In this study, we selected a landscape with mass-flowering tufted vetches to determine the spatial scale of waylaying effect of honey bees as well as the consequence of waylaying effect on vetch pollination service. The spatial scale of waylaying effect was determined by the strongest association between honey bee density and distance, selected from a gradient of nested circular buffers centering on apiaries in three different locations. Linear models were used to predict the influence of flower visitor densities on pollination service. For our landscape, honey bee densities were best associated with distances at spatial scales of 500 m, 1150 m, and 1400 m respectively for the three locations of apiaries. Honey bee was the only pollinator whose density displayed a positive relationship with pollination service. At the scales of effect, honey bee density and pollination service declined along the distance. Our findings suggest that the waylaying effect of pollinators needs to be examined at a specific spatial scale and farmers who use honey bees to pollinate their mass-flowering crops need to consider the spatial scale of waylaying effect of pollinators in order to maximize pollination service within agricultural ecosystems.
Assuntos
Abelhas/fisiologia , Flores/fisiologia , Polinização , Animais , China , Produtos Agrícolas/fisiologia , Modelos Lineares , Magnoliopsida/fisiologiaRESUMO
Ischemic stroke (IS) is a multifactorial disorder, and genetic factors act as important contributors to its onset and progression. Inflammation is a key event that is closely associated with the pathophysiology of IS. The association of genetic polymorphisms of inflammatory cytokines with IS remains poorly understood. We investigated the relationship between the variable number of tandem repeats (VNTR) for IL-4, which is an important biomarker of inflammation, and the risk of IS. To assess the nature of the VNTR polymorphism in IL-4 and identify any links with IS, we recruited 200 subjects from a unique population that has 60% European and 40% East Asian ancestry. The subjects comprised 100 IS patients diagnosed using magnetic resonance imaging within 24 h of symptom onset and 100 age-, gender- and ethnicity-matched normal healthy controls. VNTR was identified using high-performance capillary electrophoresis with specially designed tailed primers. The IL-4 VNTR polymorphism was significantly associated with IS after adjustment for cardiovascular risk factors (OR = 0.571, 95%CI = 0.330-0.949, P < 0.05). Our data indicate that IL-4 VNTR polymorphism may affect susceptibility to IS in the Chinese Uyghur population. Moreover, total cholesterol, fasting blood glucose, waist-to-hip ratio, hypertension, history of heart diseases, and negative events may increase the risk of IS, with a trend for HDL to be a protective factor for IS in the Uyghur population.