An investigation and analysis of visual sensitivity under conditions of glare

Imperial Users onl

Hyperglycemia: Cell death in a cave

AbstractMitochondria play a central role in mediating high glucose-induced apoptosis. A recent study has shown that increases in glucose levels induce significant alterations in caveolae components, suggesting that high glucose may affect apoptotic signaling initiated in caveolae

Managing Smooth Bromegrass Pastures in South Dakota

Smooth bromegrass is a cool-season grass introduced into the U.S. in the latter part of the 19th century. Because of its highly developed root system, smooth bromegrass is resistant to wide temperature extremes and extensive drought. This resistance has allowed it to become a dominant species in pastures and on native rangeland in eastern and central South Dakota. It is a leafy and sod-forming perennial that spreads aggressively through seeds and rhizomes and establishes well on deep, well-drained silt, clay loam, or sandy soils (Fig 1)

One Year Post-\u3cem\u3eBruen\u3c/em\u3e: An Empirical Assessment

In the year after New York State Rifle & Pistol Association v. Bruen, a steady stream of highly publicized opinions struck down a wide range of previously upheld gun restrictions. Courts declared unconstitutional policies ranging from assault weapon bans to domestic abuser prohibitions to various limits on publicly carrying handguns. Those opinions can frequently be paired with others reaching the opposite conclusion. The extent to which Bruen shook up the Second Amendment landscape and has caused widespread confusion in the courts is starting to come into focus. This Essay measures Bruen’s aftereffects by statistically analyzing a year’s worth of Second Amendment opinions. We coded more than 450 challenges for dozens of variables including both case and judge characteristics, resulting in a comprehensive post-Bruen Second Amendment dataset. The findings of our analysis provide an objective basis for assessing the upheaval wrought by Bruen and highlight both unanswered questions and immense challenges for Second Amendment doctrine in the coming years

Predicting Forage Production, Stocking Rate, and Beef Production in Eastern South Dakota: A Case Study

In the summer of 1999, the Hand and Hyde County Bootstraps group met to form a working group to better understand “Management Intensive” Grazing (MIG) systems. From this working group of ranchers and state and federal agency personnel, evolved a goal to establish six demonstration sites in South Dakota (Figure 1). In 2000, the first demonstration site was established by Jim Faulstich near Highmore, SD in Hyde County. This site is a 320 acre pasture dominated by native mixed-grass prairie vegetation with some introduced species such as smooth bromegrass, Kentucky bluegrass, and crested wheatgrass. The pasture was fenced into 21 paddocks and water was developed using aboveground pipeline. Cattle weights, forage biomass, forage utilization, and climate data were measured. This report summarizes the first six years of the study and provides some predictive tools for forage production, stocking rate, and beef production based on climate data

Plant Community Patterns on Upland Prairie in the Eastern Nebraska Sandhills

Topography is an important factor in determining vegetation patterns in grasslands. We collected frequency of occurrence data from transects on dune tops, south-facing slopes, north-facing slopes, and interdunal valleys in the eastern Sandhills of Nebraska to determine the effect of topographical position on plant species composition. We used canonical discriminant analysis to separate the four topographical positions based on frequency of occurrence of the 18 principal planttaxa. Topographic position played an important role in plant distribution on upland prairie with interdunal transects strongly separated from transects on other topographical positions. Bluegrasses (Poa L. spp.), switchgrass (Panicum virgatum L.), and white sage (Artemisia ludoviciana Nutt.) were highly associated with interdunal valleys. Little bluestem [Schizachyrium scoparium (Michx.)] and cool-season grasses, such as needlegrasses (Stipa L. spp.) and Junegrass [Koeleria pyramidata (Lam.) Beauv.], tended to be associated with north-facing slopes and warm-season grasses, such as prairie sandreed [Calamovilfa longifolia (Hook) Scrihn.] and sand bluestem (Andropogon hallii Hack.), tended to be associated with south-facing slopes. Sedges (Carex L. spp.), western ragweed (Ambrosia psilostachya DC.), and Scribner dichanthelium [Dichanthelium oligosanthes (Schult.) Gould var. scribnerianum (Nash)] were the most common taxa occurring over all topographic positions. Aspect proved to be an important factor in influencing vegetation distribution in the eastern Sandhills of Nebraska

Phylogeographic inference of Sumatran ranids bearing gastromyzophorous tadpoles with regard to the Pleistocene drainage systems of Sundaland.

Rivers are known to act as biogeographic barriers in several strictly terrestrial taxa, while possibly serving as conduits of dispersal for freshwater-tolerant or -dependent species. However, the influence of river systems on genetic diversity depends on taxa-specific life history traits as well as other geographic factors. In amphibians, several studies have demonstrated that river systems have only minor influence on their divergence. Here, we assess the role of the paleodrainage systems of the Sunda region (with a focus on the island of Sumatra) in shaping the evolutionary history of two genera of frogs (Sumaterana and Wijayarana) whose tadpoles are highly dependent on cascading stream habitats. Our phylogenetic results show no clear association between the genetic diversification patterns of both anurans genera and the existence of paleodrainage systems. Time-calibrated phylogenies and biogeographical models suggest that these frogs colonized Sumatra and diversified on the island before the occurrence of the Pleistocene drainage systems. Both genera demonstrate phylogenetic structuring along a north-south geographic axis, the temporal dynamics of which coincide with the geological chronology of proto Sumatran and -Javan volcanic islands. Our results also highlight the chronic underestimation of Sumatran biodiversity and call for more intense sampling efforts on the island

Spring Clipping, Fire, and Simulated Increased Atmospheric Nitrogen Deposition Effects on Tallgrass Prairie Vegetation

Defoliation aimed at introduced cool-season grasses, which uses similar resources of native grasses, could substantially reduce their competitiveness and improve the quality of the northern tallgrass prairie. The objective was to evaluate the use of early season clipping and fire in conjunction with simulated increased levels of atmospheric nitrogen deposition on foliar canopy cover of tallgrass prairie vegetation. This study was conducted from 2009 to 2012 at two locations in eastern South Dakota. Small plots arranged in a split-plot treatment design were randomized in four complete blocks on a warm-season grass interseeded and a native prairie site in east-central South Dakota. The whole plot consisted of seven treatments: annual clip, biennial clip, triennial clip, annual fire, biennial fire, triennial fire, and undefoliated control. The clip plots consisted of weekly clipping in May to simulate heavy grazing. Fire was applied in late April or early May. The subplot consisted of nitrogen applied at 0 or 15 kg N · ha−1 in early June. All treatments were initially applied in 2009. Biennial and triennial treatments were reapplied in 2011 and 2012, respectively. Canopy cover of species/major plant functional groups was estimated in late August/early September. Annual clipping was just as effective as annual fire in increasing native warm-season grass and decreasing introduced cool-season grass cover. Annual defoliation resulted in greater native warm-season grass cover, less introduced cool-season grass cover, and less native cool-season grass cover than biennial or triennial defoliation applications. Low levels of nitrogen did not affect native warm-season grass or introduced cool-season cover for any of the defoliation treatments, but it increased introduced cool-season grass cover in the undefoliated control at the native prairie site. This study supports the hypothesis that appropriately applied management results in consistent desired outcomes regardless of increased simulated atmospheric nitrogen depositions