Cooling requirements fueled the collapse of a desert bird community from climate change.

Climate change threatens global biodiversity by increasing extinction risk, yet few studies have uncovered a physiological basis of climate-driven species declines. Maintaining a stable body temperature is a fundamental requirement for homeothermic animals, and water is a vital resource that facilitates thermoregulation through evaporative cooling, especially in hot environments. Here, we explore the potential for thermoregulatory costs to underlie the community collapse of birds in the Mojave Desert over the past century in response to climate change. The probability of persistence was lowest for species occupying the warmest and driest sites, which imposed the greatest cooling costs. We developed a general model of heat flux to evaluate whether water requirements for evaporative cooling contributed to species' declines by simulating thermoregulatory costs in the Mojave Desert for 50 bird species representing the range of observed declines. Bird species' declines were positively associated with climate-driven increases in water requirements for evaporative cooling and exacerbated by large body size, especially for species with animal-based diets. Species exhibiting reductions in body size across their range saved up to 14% in cooling costs and experienced less decline than species without size reductions, suggesting total cooling costs as a mechanism underlying Bergmann's rule. Reductions in body size, however, are unlikely to offset the 50 to 78% increase in cooling costs threatening desert birds from future climate change. As climate change spreads warm, dry conditions across the planet, water requirements are increasingly likely to drive population declines, providing a physiological basis for climate-driven extinctions

Specific Isotopic Labeling and Photooxidation-linked Structural Changes in the Manganese-stabilizing Subunit of Photosystem II

Photosystem II (PSII) oxidizes water to molecular oxygen; the catalytic site is a cluster of four manganese ions. The catalytic site undergoes four sequential light-driven oxidation steps to form oxygen; these sequentially oxidized states are referred to as the Sn states, where n refers to the number of oxidizing equivalents stored. The extrinsic manganese stabilizing protein (MSP) of PSII influences the efficiency and stability of the manganese cluster, as well as the rates of the S state transitions. To understand how MSP influences photosynthetic water oxidation, we have employed isotope editing and difference Fourier transform infrared spectroscopy. MSP was expressed in Escherichia coli under conditions in which MSP aspartic and glutamic acid residues label at yields of 65 and 41%, respectively. Asparagine and glutamine were also labeled by this approach. GC/MS analysis was consistent with minimal scrambling of label into other amino acid residues and with no significant scrambling into the peptide bond. Selectively labeled MSP was then reconstituted to PSII, which had been stripped of native MSP. Difference Fourier transform infrared spectroscopy was used to probe the S 1QA to S2QA- transition at 200 K, as well as the S1QB to S2Q B- transition at 277 K. These experiments show that aspargine, glutamine, and glutamate residues in MSP are perturbed by photooxidation of manganese during the S1 to S2 transition

Cost efficient narrow linewidth laser transmitter for coherent detection

Authors present a cost efficient narrow linewidth laser transmitter for future coherent detection systems. The spectral purity of the laser allows the phase modulation of data signals at bit rates as low as 155 Mb/s

Effects of Forest Fire on Young-of-the-year Northern Pike, Esox lucius, in the Northwest Territories

In 1998, a forest fire burned 58% of the forested shoreline surrounding Tibbitt Lake, Northwest Territories, including riparian vegetation used by Northern Pike (Esox lucius) as spawning habitat. This presented an opportunity to investigate the effects that habitat disturbance from a natural forest fire had on young-of-the-year (Y-O-Y) Northern Pike. Pike fry were collected from three burned and three unburned sites around Tibbitt Lake in 1999 (the first post-fire spawning season) and again in 2001. Differences in size and relative abundance were evaluated between sites. Y-O-Y Northern Pike were significantly larger at the unburned sites (P<0.01) and the relative abundance of Y-O-Y Northern Pike increased significantly at burned sites (alpha=0.1; P<0.07) following re-vegetation two years post fire. These differences may be due to fire-induced changes in physical habitat or food availability. Forest fires decrease the density of riparian vegetation, which likely provides better spawning and rearing habitat for Northern Pike in the long-term.En 1998, un feu de forêt a brûlé 58% de la rive boisée entourant le lac Tibbitt, situé dans les Territoires du Nord-Ouest, y compris la végétation riveraine utilisé par le grand brochet (Esox lucius) comme habitat de fraie. Cet événement a présenté une occasion pour étudier les effets causés par un feu de foret sur l'habitat de jeunes de l'année du grand brochet. Les jeunes brochets ont été recueillis sur trois sites brûlées et trois sites non brûlés autour du lac Tibbitt en 1999 (la première année de fraie après le feu de forêt) et à nouveau en 2001. La différence de grandeur et l'abondance relative des poissons ont été analysés entre les différents sites. Les jeunes grands brochets aux sites non-atteints par le feu étaient considérablement plus grands (P < 0,01) que ceux aux sites brulés. Les sites brulés, subissant une rapide revégétation dans les deux années après le feu, ont augmenté en abondance relative de jeunes grands brochets (alpha = 0,1, P < 0,07). Ces différences peuvent être dues aux changements induits par le feu sur l'aspect physique de l'habitat ou sur la disponibilité de nourriture. Les incendies de forêt réduisent la densité de la végétation riveraine, qui fournit probablement de meilleure habitat de fraie et d'alevinage pour le grand brochet à long terme

The receptor protein tyrosine phosphatase PTPRB negatively regulates FGF2-dependent branching morphogenesis

PTPRB is a transmembrane protein tyrosine phosphatase known to regulate blood vessel remodelling and angiogenesis. Here we demonstrate that PTPRB negatively regulates branching morphogenesis in the mammary epithelium. We show that Ptprb is highly expressed in adult mammary stem cells and also, although at lower levels, in estrogen receptor positive luminal cells. During mammary development Ptprb expression is down-regulated during puberty, a period of extensive of ductal outgrowth and branching. In vivo shRNA knockdown of Ptprb in the cleared mammary fat pad transplant assay resulted in smaller epithelial outgrowths with an increased branching density and also increased branching in an in vitro organoid assay. Organoid branching was dependent on stimulation by FGF2, and Ptprb knockdown in mammary epithelial cells resulted in a higher level of FGFR activation and ERK1/2 phosphorylation, both at baseline and following FGF2 stimulation. Therefore, PTPRB regulates branching morphogenesis in the mammary epithelium by modulating the response of the FGFR signalling pathway to FGF stimulation. Considering the importance of branching morphogenesis in multiple taxa, our findings have general importance outside mammary developmental biology

Why equality? On justifying liberal egalitarianism

The debate over the nature of egalitarianism has come to dominate political philosophy. As ever more sophisticated attempts are made to describe the principles of an egalitarian distribution or to specify the good or goods that should be distributed equally, little is said about the fundamental basis of equality. In virtue of what should people be regarded as equal? Egalitarians have tended to dismiss this question of fundamental equality. In the first part of the paper I will examine some of these strategies of marginalisation and assess whether the issue of fundamental equality matters. Jeremy Waldron has criticised this strategy of avoidance in his recent book God, Locke and equality. He argues that Locke's turn to a theistic grounding for fundamental equality provides a better approach to the problem than the approach taken by contemporary liberals such as John Rawls. I will examine Waldron's critique of Rawls and show that it is wanting. I will conclude by suggesting that Rawls's approach to the issue has a bearing on the way in which equality should be understood as a political value. This argument for the primacy of a political conception of egalitarianism has a bearing on the interconnection between core liberal values and the idea of the state that has been emphasised by Rawls, Dworkin and Nagel

Mock Certification Basis for an Unmanned Rotorcraft for Precision Agricultural Spraying

This technical report presents the results of a case study using a hazard-based approach to develop preliminary design and performance criteria for an unmanned agricultural rotorcraft requiring airworthiness certification. This case study is one of the first in the public domain to examine design and performance criteria for an unmanned aircraft system (UAS) in tandem with its concept of operations. The case study results are intended to support development of airworthiness standards that could form a minimum safety baseline for midsize unmanned rotorcraft performing precision agricultural spraying operations under beyond visual line-of-sight conditions in a rural environment. This study investigates the applicability of current methods, processes, and standards for assuring airworthiness of conventionally piloted (manned) aircraft to assuring the airworthiness of UAS. The study started with the development of a detailed concept of operations for precision agricultural spraying with an unmanned rotorcraft (pp. 5-18). The concept of operations in conjunction with a specimen unmanned rotorcraft were used to develop an operational context and a list of relevant hazards (p. 22). Minimum design and performance requirements necessary to mitigate the hazards provide the foundation of a proposed (or mock) type certification basis. A type certification basis specifies the applicable standards an applicant must show compliance with to receive regulatory approval. A detailed analysis of the current airworthiness regulations for normal-category rotorcraft (14 Code of Federal Regulations, Part 27) was performed. Each Part 27 regulation was evaluated to determine whether it mitigated one of the relevant hazards for the specimen UAS. Those regulations that did were included in the initial core of the type certification basis (pp. 26-31) as written or with some simple modifications. Those regulations that did not mitigate a recognized hazard were excluded from the certification basis. The remaining regulations were applicable in intent, but the text could not be easily tailored. Those regulations were addressed in separate issue papers. Exploiting established regulations avoids the difficult task of generating and interpreting novel requirements, through the use of acceptable, standardized language. The rationale for the disposition of the regulations was assessed and captured (pp. 58-115). The core basis was then augmented by generating additional requirements (pp. 38-47) to mitigate hazards for an unmanned sprayer that are not covered in Part 27

Oral ketamine vs placebo in patients with cancer-related neuropathic pain

Ketamine hydrochloride is used as an adjuvant treatment for cancer-related neuropathic pain, but evidence of its effectiveness is limited.1 Findings of a large trial investigating the use of ketamine for general cancer pain were negative, but the population studied did not specifically have neuropathic pain. A randomized trial of oral ketamine for cancer-related neuropathic pain has been called for, and the present trial addresses that need

Fabrication and measurement of a photonic crystal waveguide integrated with a semiconductor optical amplifier

A III-V semiconductor photonic crystal (PhC) waveguide is integrated into a semiconductor optical amplifier (SOA); this has the potential to reshape pulses that are distorted and chirped on propagation through the SOA. The PhC waveguide is modeled using the three-dimensional (3D) finite difference time domain (FDTD) method initially for the ideal case of infinite depth holes, and this shows a ministop band close to 1600 nm. The PhC waveguide is then fabricated into a commercial SOA using focused ion beam etching. The optical power measured at the output of the PhC-SOA waveguide shows evidence of a ministop band but with a small stopband depth. More realistic 3D FDTD modeling including effects of finite hole depth and vertical layer structure is then shown to give much better agreement with measured results. Finally predictions are made for the performance of a membrane structure