1,146 research outputs found

    Unipolar Induction

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    Nuclear Phenomena and Cosmis Rays

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    Author Institution: Director, Bartol Research Foundatio

    Constraints on the Electrical Charge Asymmetry of the Universe

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    We use the isotropy of the Cosmic Microwave Background to place stringent constraints on a possible electrical charge asymmetry of the universe. We find the excess charge per baryon to be qep<1026eq_{e-p}<10^{-26}e in the case of a uniform distribution of charge, where ee is the charge of the electron. If the charge asymmetry is inhomogeneous, the constraints will depend on the spectral index, nn, of the induced magnetic field and range from qep<5×1020eq_{e-p}<5\times 10^{-20}e (n=2n=-2) to qep<2×1026eq_{e-p}<2\times 10^{-26}e (n2n\geq 2). If one could further assume that the charge asymmetries of individual particle species are not anti-correlated so as to cancel, this would imply, for photons, qγ<1035eq_\gamma< 10^{-35}e; for neutrinos, qν<4×1035eq_\nu<4\times10^{-35}e; and for heavy (light) dark matter particles qdm<4×1024eq_{\rm dm}<4\times10^{-24}e (qdm<4×1030eq_{\rm dm}<4\times10^{-30}e).Comment: New version to appear in JCA

    Origin of Magnetic Fields in the Universe Due to Nonminimal Gravitational-Electromagnetic Coupling

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    Basically the only existing theories for the creation of a magnetic field B in the Universe are the creation of a seed field of order 10^{-20} G in spiral galaxy which is subsequently supposedly amplified up to the observed 10^{-6} - 10^{-5} G by a dynamo process or a seed intergalactic field of magnitude 10^{-12} - 10^{-10} G which is amplified by collapse and differential rotation. No satisfactory dynamo theory, however, exists today. We show that a 10^{-6} - 10^{-5} G magnetic field in spiral galaxies is directly obtained from a nonminimal gravitational-electromagnetic coupling, without the need of significant dynamo amplification.Comment: 5 pages, Latex (Revtex), no figures, To appear in PR

    Estimating vehicle carbon dioxide emissions from Boulder, Colorado, using horizontal path-integrated column measurements

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    We performed 7.5 weeks of path-integrated concentration measurements of CO2, CH4, H2O, and HDO over the city of Boulder, Colorado. An open-path dual-comb spectrometer simultaneously measured time-resolved data across a reference path, located near the mountains to the west of the city, and across an over-city path that intersected two-thirds of the city, including two major commuter arteries. By comparing the measured concentrations over the two paths when the wind is primarily out of the west, we observe daytime CO2 enhancements over the city. Given the warm weather and the measurement footprint, the dominant contribution to the CO2 enhancement is from city vehicle traffic. We use a Gaussian plume model combined with reported city traffic patterns to estimate city emissions of on-road CO2 as (6.2±2.2) × 105&thinsp;metric tons (t) CO2&thinsp;yr−1 after correcting for non-traffic sources. Within the uncertainty, this value agrees with the city's bottom-up greenhouse gas inventory for the on-road vehicle sector of 4.5×105&thinsp;t CO2&thinsp;yr−1. Finally, we discuss experimental modifications that could lead to improved estimates from our path-integrated measurements.</p

    Children’s Feedback Preferences in Response to an Experimentally Manipulated Peer Evaluation Outcome: The Role of Depressive Symptoms

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    The present study examined the linkage between pre-adolescent children’s depressive symptoms and their preferences for receiving positive vs. negative feedback subsequent to being faced with an experimentally manipulated peer evaluation outcome in real time. Participants (n = 142) ages 10 to 13, played a computer contest based on the television show Survivor and were randomized to either a peer rejection (i.e., receiving the lowest total ‘likeability’ score from a group of peer-judges), a peer success (i.e., receiving the highest score), or a control peer evaluation condition. Children’s self-reported feedback preferences were then assessed. Results revealed that participants assigned to the negative evaluation outcome, relative to either the success or the control outcome, showed a significantly higher subsequent preference for negatively tuned feedback. Contrary to previous work and predictions derived from self-verification theory, children higher in depressive symptoms were only more likely to prefer negative feedback in response to the negative peer evaluation outcome. These effects for depression were not accounted for by either state mood at baseline or mood change in response to the feedback manipulation

    Quasar accretion disk sizes from continuum reverberation mapping in the DES standard-star fields

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    Measurements of the physical properties of accretion disks in active galactic nuclei are important for better understanding the growth and evolution of supermassive black holes. We present the accretion disk sizes of 22 quasars from continuum reverberation mapping with data from the Dark Energy Survey (DES) standard star fields and the supernova C fields. We construct continuum lightcurves with the \textit{griz} photometry that span five seasons of DES observations. These data sample the time variability of the quasars with a cadence as short as one day, which corresponds to a rest frame cadence that is a factor of a few higher than most previous work. We derive time lags between bands with both JAVELIN and the interpolated cross-correlation function method, and fit for accretion disk sizes using the JAVELIN Thin Disk model. These new measurements include disks around black holes with masses as small as 107\sim10^7 MM_{\odot}, which have equivalent sizes at 2500\AA \, as small as 0.1\sim 0.1 light days in the rest frame. We find that most objects have accretion disk sizes consistent with the prediction of the standard thin disk model when we take disk variability into account. We have also simulated the expected yield of accretion disk measurements under various observational scenarios for the Large Synoptic Survey Telescope Deep Drilling Fields. We find that the number of disk measurements would increase significantly if the default cadence is changed from three days to two days or one day.Comment: 33 pages, 24 figure

    J D Bernal: philosophy, politics and the science of science

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    This paper is an examination of the philosophical and political legacy of John Desmond Bernal. It addresses the evidence of an emerging consensus on Bernal based on the recent biography of Bernal by Andrew Brown and the reviews it has received. It takes issue with this view of Bernal, which tends to be admiring of his scientific contribution, bemused by his sexuality, condescending to his philosophy and hostile to his politics. This article is a critical defence of his philosophical and political position

    J D Bernal: philosophy, politics and the science of science

    Get PDF
    This paper is an examination of the philosophical and political legacy of John Desmond Bernal. It addresses the evidence of an emerging consensus on Bernal based on the recent biography of Bernal by Andrew Brown and the reviews it has received. It takes issue with this view of Bernal, which tends to be admiring of his scientific contribution, bemused by his sexuality, condescending to his philosophy and hostile to his politics. This article is a critical defence of his philosophical and political position

    Overlooking Subvisible Particles in Therapeutic Protein Products: Gaps that may Compromise Product Quality

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    Therapeutic protein products provide unique and effective treatments for numerous human diseases and medical conditions. In many cases, these treatments are used chronically to slow disease progression, reduce morbidity and/or to replace essential proteins that are not produced endogenously in patients. Therefore, any factor that reduces or eliminates the effectiveness of the treatment can lead to patient suffering and even death. One means by which efficacy of therapeutic proteins can be compromised is by an immune response, resulting in antibody-mediated neutralization of the protein’s activity or alterations in bioavailability.1,2 For example, in the case of treatment of hemophilia A, neutralizing antibodies to Factor VIII can cause life-threatening bleeding episodes, resulting in significant morbidity and necessitating treatment with a prolonged course of a tolerance-inducing therapy to reverse immunity.3,4 In other cases, drug-induced antibodies to a therapeutic version of an endogenous protein can cross-react with and neutralize the patient’s endogenous protein. If the endogenous protein serves a non-redundant biological function, such an immune response can have devastating results. For example, pure red cell aplasia can result from neutralizing antibodies to epoetin alpha. 1,2 It is well established that protein aggregates in therapeutic protein products can enhance immunogenicity2, and such an effect is therefore an important risk factor to consider when assessing product quality. The purpose of this commentary is to accomplish the following: i. provide brief summaries on the factors affecting protein aggregation and the key aspects of protein aggregates that are associated with immunogenicity; ii. emphasize the current scientific gaps in understanding and analytical limitations for quantitation of species of large protein aggregates that are referred to as subvisible particles, with specific consideration of those particles 0.1–10 μm in size; iii. offer a rationale for why these gaps may compromise the safety and/or efficacy of a product; iv. provide scientifically sound, risked based recommendations/conclusions for assessment and control of such aggregate species
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