Simulation of Atmospheric Muon and Neutrino Fluxes with CORSIKA

The fluxes of atmospheric muons and neutrinos are calculated by a three dimensional Monte Carlo simulation with the air shower code CORSIKA using the hadronic interaction models DPMJET, VENUS, GHEISHA, and UrQMD. For the simulation of low energy primary particles the original CORSIKA has been extended by a parametrization of the solar modulation and a microscopic calculation of the directional dependence of the geomagnetic cut-off functions. An accurate description for the geography of the Earth has been included by a digital elevation model, tables for the local magnetic field in the atmosphere, and various atmospheric models for different geographic latitudes and annual seasons. CORSIKA is used to calculate atmospheric muon fluxes for different locations and the neutrino fluxes for Kamioka. The results of CORSIKA for the muon fluxes are verified by an extensive comparison with recent measurements. The obtained neutrino fluxes are compared with other calculations and the influence of the hadronic interaction model, the geomagnetic cut-off and the local magnetic field on the neutrino fluxes is investigated.Comment: revtex, 19 pages, 19 Postscript figures, submitted to Phys. Rev.

High-Resolution Satellite Measurements of the Atmospheric Boundary Layer Response to SST Variations along the Agulhas Return Current

The marine atmospheric boundary layer (MABL) response to sea surface temperature (SST) perturbations with wavelengths shorter than 30° longitude by 10° latitude along the Agulhas Return Current (ARC) is described from the first year of SST and cloud liquid water (CLW) measurements from the Advanced Microwave Scanning Radiometer (AMSR) on the Earth Observing System (EOS) Aqua satellite and surface wind stress measurements from the QuikSCAT scatterometer. AMSR measurements of SST at a resolution of 58 km considerably improves upon a previous analysis that used the Reynolds SST analyses, which underestimate the short-scale SST gradient magnitude over the ARC region by more than a factor of 5. The AMSR SST data thus provide the first quantitatively accurate depiction of the SST-induced MABL response along the ARC. Warm (cold) SST perturbations produce positive (negative) wind stress magnitude perturbations, leading to short-scale perturbations in the wind stress curl and divergence fields that are linearly related to the crosswind and downwind components of the SST gradient, respectively. The magnitudes of the curl and divergence responses vary seasonally and spatially with a response nearly twice as strong during the winter than during the summer along a zonal band between 40° and 50°S. These seasonal variations closely correspond to seasonal and spatial variability of large-scale MABL stability and surface sensible heat flux estimated from NCEP reanalysis fields. SST-induced deepening of the MABL over warm water is evident in AMSR measurements of CLW. Typical annual mean differences in cloud thickness between cold and warm SST perturbations are estimated to be about 300

Thermoregulatory, metabolic, and cardiovascular responses during 88 min of full-body ice immersion - A case study.

Exposure to extreme cold environments is potentially life-threatening. However, the world record holder of full-body ice immersion has repeatedly demonstrated an extraordinary tolerance to extreme cold. We aimed to explore thermoregulatory, metabolic, and cardiovascular responses during 88 min of full-body ice immersion. We continuously measured gastrointestinal temperature (Tgi ), skin temperature (Tskin), blood pressure, and heart rate (HR). Oxygen consumption (VO2 ) was measured at rest, and after 45 and 88 min of ice immersion, in order to calculate the metabolic heat production. Tskin dropped significantly (28-34°C to 4-15°C) and VO2 doubled (5.7-11.3 ml kg-1  min-1 ), whereas Tgi (37.6°C), HR (72 bpm), and mean arterial pressure (106 mmHg) remained stable during the first 30 min of cold exposure. During the remaining of the trial, Tskin and VO2 remained stable, while Tgi gradually declined to 37.0°C and HR and mean arterial blood pressure increased to maximum values of 101 bpm and 115 mmHg, respectively. Metabolic heat production in rest was 169 W and increased to 321 W and 314 W after 45 and 80 min of ice immersion. Eighty-eight minutes of full-body ice immersion resulted in minor changes of Tgi and cardiovascular responses, while Tskin and VO2 changed markedly. These findings may suggest that our participant can optimize his thermoregulatory, metabolic, and cardiovascular responses to challenge extreme cold exposure

A Survey of Air-to-Ground Propagation Channel Modeling for Unmanned Aerial Vehicles

In recent years, there has been a dramatic increase in the use of unmanned aerial vehicles (UAVs), particularly for small UAVs, due to their affordable prices, ease of availability, and ease of operability. Existing and future applications of UAVs include remote surveillance and monitoring, relief operations, package delivery, and communication backhaul infrastructure. Additionally, UAVs are envisioned as an important component of 5G wireless technology and beyond. The unique application scenarios for UAVs necessitate accurate air-to-ground (AG) propagation channel models for designing and evaluating UAV communication links for control/non-payload as well as payload data transmissions. These AG propagation models have not been investigated in detail when compared to terrestrial propagation models. In this paper, a comprehensive survey is provided on available AG channel measurement campaigns, large and small scale fading channel models, their limitations, and future research directions for UAV communication scenarios

Unionoida (Mollusca: Margaritiferidae, Unionidae) in Arkansas, Third Status Review

We analyzed stream inventories, phylogeographic studies, community and population estimates, life history and reproductive biology research, and suitable habitat investigations conducted from 1997-2008, as well as the Arkansas Natural Heritage Commission mussel database, to update the conservation status for all native freshwater unionoid bivalves thought to occur in Arkansas. Prior to this study, Harris et al. (1997) reviewed the distribution and status of 75 freshwater mussels considered native to Arkansas and ranked 22 species as endangered, threatened or special concern. We now recognize 85 mussel taxa in Arkansas; however, some of those have yet to be described or their nomenclature remains in a state of flux. The previous inclusion of Fusconaia subrotunda (I. Lea 1831) and Obovaria subrotunda (Rafinesque 1820) in the Arkansas native mussel fauna was based on misidentifications. Within the Arkansas mussel fauna, 19 species (22%) are now considered Endangered, 5 species (6%) are ranked as Threatened, 20 species (24%) are of Special Concern, and unfortunately, 1 species has probably been extirpated

First results of the air shower experiment KASCADE

The main goals of the KASCADE (KArlsruhe Shower Core and Array DEtector) experiment are the determination of the energy spectrum and elemental composition of the charged cosmic rays in the energy range around the knee at ca. 5 PeV. Due to the large number of measured observables per single shower a variety of different approaches are applied to the data, preferably on an event-by-event basis. First results are presented and the influence of the high-energy interaction models underlying the analyses is discussed.Comment: 3 pages, 3 figures included, to appear in the TAUP 99 Proceedings, Nucl. Phys. B (Proc. Suppl.), ed. by M. Froissart, J. Dumarchez and D. Vignau

Electron, Muon, and Hadron Lateral Distributions Measured in Air-Showers by the KASCADE Experiment

Measurements of electron, muon, and hadron lateral distributions of extensive air showers as recorded by the KASCADE experiment are presented. The data cover the energy range from about 5x10^14 eV up to almost 10^17 eV and extend from the inner core region to distances of 200 m. The electron and muon distributions are corrected for mutual contaminations by taking into account the detector properties in the experiment. All distributions are well described by NKG-functions. The scale radii describing the electron and hadron data best are approx. 30 m and 10 m, respectively. We discuss the correlation between scale radii and `age' parameter as well as their dependence on shower size, zenith angle, and particle energy threshold.Comment: 28 pages, 14 figures, Accepted for publication in Astroparticle Physic

A wirelessly powered and controlled device for optical neural control of freely-behaving animals

Optogenetics, the ability to use light to activate and silence specific neuron types within neural networks in vivo and in vitro, is revolutionizing neuroscientists' capacity to understand how defined neural circuit elements contribute to normal and pathological brain functions. Typically, awake behaving experiments are conducted by inserting an optical fiber into the brain, tethered to a remote laser, or by utilizing an implanted light-emitting diode (LED), tethered to a remote power source. A fully wireless system would enable chronic or longitudinal experiments where long duration tethering is impractical, and would also support high-throughput experimentation. However, the high power requirements of light sources (LEDs, lasers), especially in the context of the extended illumination periods often desired in experiments, precludes battery-powered approaches from being widely applicable. We have developed a headborne device weighing 2 g capable of wirelessly receiving power using a resonant RF power link and storing the energy in an adaptive supercapacitor circuit, which can algorithmically control one or more headborne LEDs via a microcontroller. The device can deliver approximately 2 W of power to the LEDs in steady state, and 4.3 W in bursts. We also present an optional radio transceiver module (1 g) which, when added to the base headborne device, enables real-time updating of light delivery protocols; dozens of devices can be controlled simultaneously from one computer. We demonstrate use of the technology to wirelessly drive cortical control of movement in mice. These devices may serve as prototypes for clinical ultra-precise neural prosthetics that use light as the modality of biological control.National Institutes of Health (U.S.) (NIH Director’s New Innovator Award (DP2OD002002))National Institutes of Health (U.S.) (Grant 1R01DA029639)National Institutes of Health (U.S.) (Grant 1RC1MH088182)National Institutes of Health (U.S.) (Grant 1RC2DE020919)National Institutes of Health (U.S.) (Grant 1R01NS067199)National Institutes of Health (U.S.) (Grant 1R43NS070453)National Science Foundation (U.S.) (CAREER award)National Science Foundation (U.S.) (NSF Grant DMS 1042134)National Science Foundation (U.S.) (NSF Grant DMS 0848804)National Science Foundation (U.S.) (NSF Grant EFRI 0835878)Benesse FoundationGoogle (Firm)Dr. Gerald Burnett and Marjorie BurnettUnited States. Dept. of Defense (CDMRP PTSD Program)Massachusetts Institute of TechnologyBrain & Behavior Research FoundationAlfred P. Sloan FoundationSociety for NeuroscienceMassachusetts Institute of Technology. Media LaboratoryMcGovern Institute for Brain Research at MITWallace H. Coulter Foundatio