Connectivity in Heterogeneous Landscapes: Analyzing the Effect of Topography

Animal response to landscape heterogeneity directs dispersal and affects connectivity between populations. Topographical heterogeneity is a major source of landscape heterogeneity, which is rarely studied in the contexts of movement, dispersal, or connectivity. The current study aims at characterizing and quantifying the impacts of topography on landscape connectivity. We focus on ‘hilltopping’ behavior in butterflies, a dispersal-like behavior where males and virgin females ascend to mountain summits and mate there. Our approach integrates three elements: an individual-based model for simulating animal movements across topographically heterogeneous landscapes; a formula for the accessibility of patches in homogenous landscapes; and a graphical analysis of the plots of the simulation-based vs. the formula-based accessibility values. We characterize the functional relationship between accessibility values and landscape structure (referred to as ‘accessibility patterns’) and analyze the influence of two factors: the intensity of the individuals’ response to topography, and the level of topographical noise. We show that, despite the diversity of topographical landscapes, animal response to topography results in the formation of two, quantifiable accessibility patterns. We term them ‘effectively homogeneous’ and ‘effectively channeled’. The latter, in which individuals move toward a single summit, prevails over a wide range of behavioral and spatial parameters. Therefore, ‘channeled’ accessibilities may occur in a variety of landscapes and contexts. Our work provides novel tools for understanding and predicting accessibility patterns in heterogeneous landscapes. These tools are essential for linking movement behavior, movement patterns and connectivity. We also present new insights into the practical value of ecologically scaled landscape indices.     

Comparison of three continuous positive airway pressure (CPAP) interfaces in healthy Beagle dogs during medetomidine–propofol constant rate infusions

Objective

To compare the efficacy of three continuous positive airway pressure (CPAP) interfaces in dogs on gas exchange, lung volumes, amount of leak during CPAP and rebreathing in case of equipment failure or disconnection.

小麦水分状况的光反射测量

反射测量可用于对作物的水分状况进行快速而经济的评估。该研究以土壤最大持水量为标准，设65%、52%、39%、32.5%、26%和19.5%共6个水处理水平。小麦叶片光反射的测量用数码相机进行，测量结果用L*a*b*颜色系统进行评估和分析。在该三维系统中，参数a*和b*分别描述绿/红和蓝/黄颜色的比例，参数L*用来描述颜色的浅淡。结果表明，随水胁迫加剧，小麦叶片光反射参数a*(绿/红)和/或b*(蓝/黄)在9个特定波段表现出有规律的增加，植株含水率与光反射参数b*之间呈线性负相关关系，其中与510～780 nm波段的光反射参数b*之间的决定系数r^{2最大，达到0.95。因此光反射测量可以作为小麦水分状况测量的一个重要工具。}     

Potential for increasing the zinc content in common bean using genetic improvement

A large proportion of the world’s population is at risk of developing symptoms of zinc deficiency due to its low levels in food. The objective of this research was to estimate the heritability in early hybrid generations for the zinc content character in seeds of common bean (Phaseolus vulgaris L.), to investigate possible maternal effects on zinc contents and to evaluate the potential for genetic improvement. Reciprocal F₁, and F₂ generations as well as backcross (RCP₁ and RCP₂) populations were produced by crosses of three cultivars. The seed zinc content was measured by the nitric-perchloric digestion method and using the atomic absorption spectrophotometer. The range of variation in zinc content among tested progenies was from 21.76 mg kg⁻¹ dry matter to 53.48 mg kg⁻¹ dry matter, and no significant maternal effect was discovered. Narrow sense heritability was of an intermediate 57.5% to high 77.84% value and transgressive segregation was observed. These results suggest that breeding for increased zinc content in the seeds of common bean can be quite successful; an increase of 37.3% was obtained using just the three parents tested in this study.     

Phenolic constituents and antioxidant activity of Wendita calysina leaves (Burrito), a folk Paraguayan tea

Burrito tea originates from the leaves of Wendita calysina, an indigenous Paraguayan plant, which is commonly consumed in South America and in Western countries. Phytochemical investigation of this species has led to the isolation of 14 constituents, among them 2 new flavanonols, dihydroquercetagetin (1) and 3,5,6,7,4'-pentahydroxyflavanonol (2), in addition to several known methoxyflavones, methoxyflavonols, phenylethanoid glycosides, and benzoic acid derivatives (4-14). All structures were elucidated by ESI-MS and NMR spectroscopic methods. Quantitative determination of phenolic constituents from burrito water infusions has been performed by HPLC-UV-DAD. The total antioxidant activity of the tea was measured by the ABTS(*)(+) radical cation decolorization and chemiluminescence (CL) assays and compared with the values of other commonly used herbal teas (green and black teas, mate, and rooibos).     

Web spider community response along an edge between pasture and Araucaria forest

We investigated how vegetation features and temporal variation influenced web spider richness, abundance and composition along an edge between Araucaria forest and pasture in southern Brazil. Web spiders and vegetation were surveyed four times over a 1-year period, in five 5 × 5 m plots randomised in four locations: 50 m into the pasture, 0, 50 and 250 m into the forest. We collected a total of 836 web spiders (33 morphospecies and six families). We found different web spider assemblages occurring at the pasture edge and forest interior. The richness and abundance of web spiders decreased up to 50 m towards the forest interior in all seasons, and we found a positive influence of vegetation richness on web spider abundance. In conclusion, web spider assemblages are influenced by an edge gradient, this pattern is consistent throughout the year and is strongly related to vegetation features.