Cosmic Rays from Gamma Ray Bursts in the Galaxy

The rate of terrestrial irradiation events by galactic gamma-ray bursts (GRBs) is estimated using recent standard-energy results. We assume that GRBs accelerate high-energy cosmic rays, and present results of three-dimensional simulations of cosmic rays moving in the Galactic magnetic field and diffusing through pitch-angle scattering. An on-axis GRB extinction event begins with a powerful prompt gamma-ray and neutron pulse, followed by a longer-lived phase from cosmic-ray protons and neutron-decay protons that diffuse towards Earth. Our results force a reinterpretation of reported ~ 10^{18} eV cosmic-ray anisotropies and offer a rigorous test of the model where high-energy cosmic rays originate from GRBs, which will soon be tested with the Auger Observatory.Comment: 9 pages, 4 figures, ApJ Letters, in press. Clarified limit of test-particle approximation, prediction that Auger will not confirm SUGAR source. (Data may not appear onscreen at low magnification.) Simulations at http://heseweb.nrl.navy.mil/gamma/~dermer/invest/sim/index.ht

A Biological Investigation on Plethodon Larselli

The purpose of this study is to increase the presently-lacking biological knowledge of P. larselli. A study was made, therefore, on this species relative to its geographical distribution, habitat, dehydration and rehydration rates, response to induction with varying concentrations of a gonadotropic hormone, and blood serum analysis by cellulose acetate electrophoresis. In addition, the findings of this investigation will help elucidate the relationship between P. larselli and P. vehiculum

The multisensory attentional consequences of tool use : a functional magnetic resonance imaging study

Background: Tool use in humans requires that multisensory information is integrated across different locations, from objects seen to be distant from the hand, but felt indirectly at the hand via the tool. We tested the hypothesis that using a simple tool to perceive vibrotactile stimuli results in the enhanced processing of visual stimuli presented at the distal, functional part of the tool. Such a finding would be consistent with a shift of spatial attention to the location where the tool is used. Methodology/Principal Findings: We tested this hypothesis by scanning healthy human participants’ brains using functional magnetic resonance imaging, while they used a simple tool to discriminate between target vibrations, accompanied by congruent or incongruent visual distractors, on the same or opposite side to the tool. The attentional hypothesis was supported: BOLD response in occipital cortex, particularly in the right hemisphere lingual gyrus, varied significantly as a function of tool position, increasing contralaterally, and decreasing ipsilaterally to the tool. Furthermore, these modulations occurred despite the fact that participants were repeatedly instructed to ignore the visual stimuli, to respond only to the vibrotactile stimuli, and to maintain visual fixation centrally. In addition, the magnitude of multisensory (visual-vibrotactile) interactions in participants’ behavioural responses significantly predicted the BOLD response in occipital cortical areas that were also modulated as a function of both visual stimulus position and tool position. Conclusions/Significance: These results show that using a simple tool to locate and to perceive vibrotactile stimuli is accompanied by a shift of spatial attention to the location where the functional part of the tool is used, resulting in enhanced processing of visual stimuli at that location, and decreased processing at other locations. This was most clearly observed in the right hemisphere lingual gyrus. Such modulations of visual processing may reflect the functional importance of visuospatial information during human tool use

The Mammography Screening Controversy: Who and what is heard in the press?

The objective of this project was to analyze newspaper coverage of the January 2000 meta-analysis by Gotzsche and Olsen, “Is screening for breast cancer with mammography justified?” [Lancet 355 (2000) 129]. A content analysis was performed on a comprehensive set of newspaper clippings from the UK during the 2 weeks following publication of the Lancet article. The original authors were most quoted in Wave 1 (the first weekend); the screening programme was most quoted in Wave 2 (week 2). Screening programme description, and the “quality” of the Lancet article dominated Wave 1; patient testimonials increased in Wave 2. Newspaper articles were structured as debates between experts and advocates, thereby enhancing polarisation of opinion. We suggest this is counter-productive to evidence-based patient choice and public involvement in decision-making. Medical journals’ and charities’ press releases that begin to include discussion of uncertainty inherent in medical technologies can contribute to evidence-based public deliberation