Long-term continental changes in wing length, but not bill length, of a long-distance migratory shorebird.

We compiled a >50-year record of morphometrics for semipalmated sandpipers (), a shorebird species with a Nearctic breeding distribution and intercontinental migration to South America. Our data included >57,000 individuals captured 1972-2015 at five breeding locations and three major stopover sites, plus 139 museum specimens collected in earlier decades. Wing length increased by ca.

The redistribution of non-breeding dunlins in response to the post-DDT recovery of falcons.

Large-scale changes in predator populations are occurring worldwide due to (re-)introductions, over-exploitation, or recovery after decimation by pesticides and persecution. These widespread changes may affect the distribution of their prey. We studied the continental-scale distributions of non-breeding Calidris alpina pacifica and C.

A structured threshold model for mountain pine beetle outbreak.

A vigor-structured model for mountain pine beetle outbreak dynamics within a forest stand is proposed and analyzed. This model explicitly tracks the changing vigor structure in the stand. All model parameters, other than beetle vigor preference, were determined by fitting model components to empirical data.

[The pattern of nuclear factor-kappaB activation in rats with endotoxin shock and its role in biopterin-mediated nitric oxide induction].

Objective: To investigate the pattern of nuclear factor-kappaB (NF-kappaB) activation in rats with lipopolysaccharide( LPS) shock, and to explore the mechanism of NF-kappaB signal pathway in the biopterin-mediated nitric oxide(NO) induction, as well as its role in the development of multiple organ dysfunction syndrome ( MODS) secondary to endotoxin challenge.

Methods: Fourty-seven male Wistar rats were randomly divided into control group ( C, n = 8) , LPS group ( n = 24, with 8 rats at each time-points, and shock model was made by injection of same dosage of LPS) , and pyrrolidine dithiocarbamate (PDTC) treatment group ( PDTC, n = 15, with 5 rats at each time-points, and the rats were injected with LPS and PDTC). The rats were sacrificed at 2,6,12 post-injection hour( PIH) , and the blood and tissue samples from liver, lungs and kidneys were harvested for the determination of NF-KB activity, GTP cyclohydrolase I (GTP-CH I ) , and inducible nitric oxide synthase (iNOS) mRNA expression in the liver, lungs and kidneys, plasma and tissue content of biopterin and NO, as well as hepatic and renal function, and pulmonary myeloperoxidase activity.

[The mechanisms of extracellular-signal regulated protein kinase pathway in biopterin induction in rats with endotoxic shock].

Objective: To observe the influence of treatment with the inhibitor of extracellular-signal regulated protein kinase (ERK) signal transduction pathway on the expression of biopterin/nitric oxide (NO) as well as the activation of nuclear factor-kappaB (NF-kappaB), and to clarify the potential cross-talk regulation mechanisms between ERK and NF-kappaB pathway in biopterin-mediated NO induction in rats with endotoxic shock.

Methods: Using an endotoxic shock model, 60 male Wistar rats were randomly divided into normal controls (n = 8), endotoxic shock group (n = 32) and PD98059 treatment group (n = 20). At serial time points animals in each group were sacrificed, and tissue samples from liver, lungs as well as kidneys were harvested to detect NF-kappaB activity, guanosine triphosphate-cyclohydrolase (GTP-CHI) and inducible nitric oxide synthase (iNOS) mRNA expression.

Forecasting spatially structured populations: the role of dispersal and scale.

We forecasted spatially structured population models with complex dynamics, focusing on the effect of dispersal and spatial scale on the predictive capability of nonlinear forecasting (NLF). Dispersal influences NLF ability by its influence on population dynamics. For simple 2-cell models, when dispersal is small, our ability to predict abundance in subpopulations decreased and then increased with increasing dispersal.

Harvesting in seasonal environments.

Most harvest theory is based on an assumption of a constant or stochastic environment, yet most populations experience some form of environmental seasonality. Assuming that a population follows logistic growth we investigate harvesting in seasonal environments, focusing on maximum annual yield (M.A.

[Succession pattern of artificial vegetation community and its ecological mechanism in an arid desert region].

Focusing on the artificial vegetation protection system of the Shapotou section of Baotou-Lanzhou railway in the arid desert region of China, this paper examined the dynamics of dominant plant species and the succession pattern of artificial plant community in the process of establishing and developing regional artificial vegetation. It also studied the driving force and the ecologically intrinsic mechanism of the community succession. The results demonstrated that the species composition of the artificial vegetation dramatically changed after 40 years of succession, from original artificial plant community of shrub and semi-shrub to artificial-natural desert plant community with annual herb dominated.

Effect of diffusion and spatially varying predation risk on the dynamics and equilibrium density of a predator-prey system.

Starting from natural planktonic systems, we present a new mechanism involving spatial heterogeneity, and develop a new spatial structure model of planktonic predation systems. Firstly, the effect of diffusion on the dynamics of the system is investigated. We find that diffusion of only prey or both prey and predator between different patches with different predation risk may stabilize the dynamics, depending on the flow rate.