Radon gas, useful for medical purposes, safely fixed in quartz

Radon gas is enclosed in quartz or glass ampules by subjecting the gas sealed at a low pressure in the ampules to an ionization process. This process is useful for preparing fixed radon sources for radiological treatment of malignancies, without the danger of releasing radioactive gases

Effects of methoprene on extreme temperature tolerance and reproduction of Tribolium castaneum (Coleoptera: Tenebrionidae)

The juvenile hormone analogue methoprene is a reduced-risk insecticide. It disrupts insect development of immature stages preventing the emergence of adults. Several studies have shown that lower concentrations that permit the emergence of adults also have sub-lethal effects. Exposure to methoprene (Diacon II) at 3.33 ppm reduced the heat tolerance of Tribolium castaneum (Herbst) adults. However, it did not affect the heat tolerance of larvae at 0.07 ppm. Higher concentrations of methoprene were lethal to larvae without heat treatment. Methoprene (67 ppm) had no effect on the cold tolerance of adults. Furthermore, methoprene (0.03 ppm) did not alter cold tolerance of larvae. Exposure to 15°C for 2 weeks increased the cold tolerance of adults from 4 d to 7 d, and larvae 3 d to 5 d; however, methoprene concentrations had no effect on cold tolerance. Tribolium castaneum larvae exposed to methoprene (0.001 ppm) had lower fecundity as adults. Males were more affected than females in reducing the offspring when paired with untreated mates. These results show the potential of methoprene as an emerging insecticide and a viable alternative to currently used synthetic insecticides. The data on the effect of methoprene on extreme temperature tolerance of T. castaneum have been submitted to the Journal of Stored Products Research.Keywords: Methoprene, Extreme temperature tolerance, Reproduction, Larvae, Adult

Superluminous supernovae: No threat from Eta Carinae

Recently Supernova 2006gy was noted as the most luminous ever recorded, with a total radiated energy of ~10^44 Joules. It was proposed that the progenitor may have been a massive evolved star similar to eta Carinae, which resides in our own galaxy at a distance of about 2.3 kpc. eta Carinae appears ready to detonate. Although it is too distant to pose a serious threat as a normal supernova, and given its rotation axis is unlikely to produce a Gamma-Ray Burst oriented toward the Earth, eta Carinae is about 30,000 times nearer than 2006gy, and we re-evaluate it as a potential superluminous supernova. We find that given the large ratio of emission in the optical to the X-ray, atmospheric effects are negligible. Ionization of the atmosphere and concomitant ozone depletion are unlikely to be important. Any cosmic ray effects should be spread out over ~10^4 y, and similarly unlikely to produce any serious perturbation to the biosphere. We also discuss a new possible effect of supernovae, endocrine disruption induced by blue light near the peak of the optical spectrum. This is a possibility for nearby supernovae at distances too large to be considered "dangerous" for other reasons. However, due to reddening and extinction by the interstellar medium, eta Carinae is unlikely to trigger such effects to any significant degree.Comment: 19 pages, 2 figures; Revised version as accepted for publication in Astrobiolog

Input from Torus Longitudinalis Drives Binocularity and Spatial Summation in Zebrafish Optic Tectum

Background: A continued effort in neuroscience aims to understand the way brain circuits consisting of diverse neuronal types generate complex behavior following sensory input. A common feature of vertebrate visual systems is that lower-order and higher-order visual areas are reciprocally connected. Feedforward projections confer visual responsiveness to higher-order visual neurons while feedback projections likely serve to modulate responses of lower-order visual neurons in a context-dependent manner. Optic tectum is the largest first-order visual brain area in zebrafish and is reciprocally connected with the torus longitudinalis (TL), a second-order visual brain area that does not receive retinal input. A functional role for feedback projections from TL to tectum has not been identified. Here we aim to understand how this feedback contributes to visual processing. Results: In this study, we demonstrate that TL feedback projections to tectum drive binocular integration and spatial summation in a defined tectal circuit. We performed genetically targeted, cell type-specific functional imaging in tectal pyramidal neurons (PyrNs) and their two input neuron populations: retinal ganglion cells (RGCs) and neurons in TL. We find that PyrNs encode gradual changes in scene luminance using a complement of three distinct response classes that encode different light intensity ranges. Functional imaging of RGC inputs to tectum suggest that these response classes originate in the retina and RGC input specifies PyrN functional classes. In contrast, TL input serves to endow PyrNs with large, compound receptive fields that span both retinal hemifields. Conclusions: These findings reveal a novel role for the zebrafish TL in driving binocular integration and spatial summation in tectal PyrNs. The neural circuit we describe generates a population of tectal neurons with large receptive fields tailored for detecting changes in the visual scene

Sensitivity potential to a light flavor-changing scalar boson with DUNE and NA64μ\mu

In this work, we report on the sensitivity potential of complementary muon-on-target experiments to new physics using a scalar boson benchmark model associated with charged lepton flavor violation. The NA64$\mu$ experiment at CERN uses a 160-GeV energy muon beam with an active target to search for excess events with missing energy and momentum as a probe of new physics. At the same time, the proton beam at Fermilab, which is used to produce the neutrino beam for the Deep Underground Neutrino Experiment (DUNE) will also produce a high-intensity muon beam dumped in an absorber. Combined with the liquid Argon Near Detector, the system could be used to search for similar scalar boson particles with a lower energy but higher intensity beam. We find that both NA64$\mu$ and DUNE could cover new, unexplored parts of the parameter space of the same benchmark model, providing a complementary way to search for new physics

Distribution of Breeding Ducks Relative to Habitat Characteristics in the Prairie Pothole Region of North Central Montana

Continental waterfowl population declines in the early 1980s led to the development and implementation of the North American Waterfowl Management Plan.  The plan identified wetland and grassland losses in the Prairie Pothole Region (PPR) of Canada and the United States as the major causes of low continental duck populations.  Until 2008, north central Montana was the only remaining PPR area in the United States without a ground-based annual survey to monitor breeding duck populations and quantify breeding duck habitat.  The purpose of this study was to establish an annual breeding duck survey in north central Montana to 1) develop species-specific breeding pair predictive models, and 2) apply the models to estimate the distribution of breeding ducks and identify priority areas for conservation.  We observed 10539 indicated breeding duck pairs on approximately 675 wetland basins surveyed annually from 2008-2014.  A competing models analysis was used to identify local- and landscape-scale habitat characteristics to predict breeding duck pair abundance on wetland basins.  The five most commonly observed species were modeled separately; those species were mallard (Anas platyrhynchos), northern pintail (A. acuta), gadwall (A. strepera ), northern shoveler (A. clypeata) and blue-winged teal (A. discors).  At the local scale, wetland basin area, the square root transformation of wetland basin area, and wetland basin class were important predictors for all species.  Important model predictors varied by species at the landscape scale.  We applied the models in a GIS to develop a decision support tool for conservation actions funded by the Migratory Bird Conservation Fund

Constraining the variation of the coupling constants with big bang nucleosynthesis

We consider the possibility of the coupling constants of the $SU(3)\times SU(2)\times U(1)$ gauge interactions at the time of big bang nucleosynthesis having taken different values from what we measure at present, and investigate the allowed difference requiring the shift in the coupling constants not violate the successful calculation of the primordial abundances of the light elements. We vary gauge couplings and Yukawa couplings (fermion masses) using a model in which their relative variations are governed by a single scalar field, dilaton, as found in string theory. The results include a limit on the fine structure constant $-6.0\times10^{-4}<\Delta\alpha_{EM}/\alpha_{EM}<1.5\times10^{-4}$, which is two orders stricter than the limit obtained by considering the variation of $\alpha_{EM}$ alone.Comment: 7 page

Campylobacter jejuni--an emerging foodborne pathogen.

Campylobacter jejuni is the most commonly reported bacterial cause of foodborne infection in the United States. Adding to the human and economic costs are chronic sequelae associated with C. jejuni infection--Guillian-Barré syndrome and reactive arthritis. In addition, an increasing proportion of human infections caused by C. jejuni are resistant to antimicrobial therapy. Mishandling of raw poultry and consumption of undercooked poultry are the major risk factors for human campylobacteriosis. Efforts to prevent human illness are needed throughout each link in the food chain