484 research outputs found

    Dark matter constraints on the parameter space and particle spectra in the nonminimal SUSY standard model

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    We investigate the dark matter constraints for the nonminimal SUSY standard model (NMSSM). The cosmologically restricted mass spectra of the NMSSM are compared to the minimal SUSY standard model (MSSM). The differences of the two models concerning the neutralino, sfermion and Higgs sector are discussed. The dark matter condition leads to cosmologically allowed mass ranges for the SUSY particles in the NMSSM: m_{\tilde{\chi}^0_1} < 300 GeV, m_{\tilde{e}_R} < 300 GeV, 300 GeV < m_{\tilde{u}_R} < 1900 GeV, 200 GeV < m_{\tilde{t}_1} < 1500 GeV, 350 GeV < m_{\tilde{g}} < 2100 GeV and for the mass of the lightest scalar Higgs m_{S_1} < 140 GeV.Comment: revised version to appear in Phys. Lett. B, 18 pages, LaTeX, 3 figures, uses epsfig.sty and amssymb.st

    Two-Dimensional Helioseismic Power, Phase, and Coherence Spectra of {\it Solar Dynamics Observatory} Photospheric and Chromospheric Observables

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    While the {\it Helioseismic and Magnetic Imager} (HMI) onboard the {\it Solar Dynamics Observatory} (SDO) provides Doppler velocity [VV], continuum intensity [ICI_C], and line-depth [LdLd] observations, each of which is sensitive to the five-minute acoustic spectrum, the {\it Atmospheric Imaging Array} (AIA) also observes at wavelengths -- specifically the 1600 and 1700 Angstrom bands -- that are partly formed in the upper photosphere and have good sensitivity to acoustic modes. In this article we consider the characteristics of the spatio--temporal Fourier spectra in AIA and HMI observables for a 15-degree region around NOAA Active Region 11072. We map the spatio--temporal-power distribution for the different observables and the HMI Line Core [ILI_L], or Continuum minus Line Depth, and the phase and coherence functions for selected observable pairs, as a function of position and frequency. Five-minute oscillation power in all observables is suppressed in the sunspot and also in plage areas. Above the acoustic cut-off frequency, the behaviour is more complicated: power in HMI ICI_C is still suppressed in the presence of surface magnetic fields, while power in HMI ILI_L and the AIA bands is suppressed in areas of surface field but enhanced in an extended area around the active region, and power in HMI VV is enhanced in a narrow zone around strong-field concentrations and suppressed in a wider surrounding area. The relative phase of the observables, and their cross-coherence functions, are also altered around the active region. These effects may help us to understand the interaction of waves and magnetic fields in the different layers of the photosphere, and will need to be taken into account in multi-wavelength local helioseismic analysis of active regions.Comment: 18 pages, 15 figures, to be published in Solar Physic

    A Model of Gas-Phase Transport During the Initial Stages of Sintering of Silicon Carbide

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    New Jersey 08854 Carbon, which is often used as an additive to silicon carbide powder, is thought to facilitate densification during sintering by aiding the removal of the native SiO 2 layer, which is present on the starting SiC powder. The mechanism is the reduction of SiO 2 to SiC with the formation of primarily CO gas, which diffuses out from the porous compact at a temperature below the normal sintering temperature. It has been found beneficial to hold the compact at an intermediate temperature to allow time for the CO and other gases to diffuse out before the pores close. We investigate this process using a computational model based on codiffusion of multiple gas species, which enables prediction of the gas and condensed phase compositions as a function of time and position in the specimen. The results are used to determine the optimum holding time for complete SiO 2 removal as a function of key parameters, such as specimen thickness, particle size, temperature, etc., as well as the necessary amount of C additive. The results of the modeling are consistent with the experimentally observed spatial variation of density and composition in SiC compacts

    Prodynorphin peptide immunocytochemistry in rhesus monkey brain

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    The present study describes the immunocytochemical distribution of peptides derived from the prodynorphin precursor in the brain of the rhesus monkey (Macaca mulatta). Animals were treated with colchicine (intracerebroventricularly) prior to perfusion to enhance the observation of perikaryal immunoreactivity. Using antisera generated against dynorphin A(1-17), dynorphin B(1-13), and prodynorphin(186-208) (or bridge peptide), the anatomical distribution of dynorphin systems was mapped. The results indicate a widespread neuronal localization of immunoreactivity from the cerebral cortex to the caudal medulla. Anti-dynorphin B and anti-bridge peptide sera proved useful for the demonstration of neuronal perikarya, while the dynorphin A antiserum was best for localizing terminal projection fields. Immunoreactive perikarya are located in numerous brain loci, including the cingulate cortex, caudate nucleus, amygdala, hypothalamus (especially the magnocellular nuclei), thalamus, substantia grisea centralis, parabrachial nucleus, nucleus tractus solitarius, and other nuclei. In addition, fiber and terminal immunoreactivity are seen in varying densities in the striatum and pallidum, substantia innominata, hypothalamus, substantia nigra pars reticulata, parabrachial nucleus, spinal trigeminal nucleus, and other areas. The distribution of prodynorphin peptides in the brain of the monkey is similar to that described for the rat brain; however, significant differences also exist. Other interspecies differences in the anatomy of prodynorphin and proenkephalin neuronal systems in the monkey and human brain are further discussed.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/25854/1/0000417.pd

    Constraints on the minimal supergravity model from the b->s+\gamma decay

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    The constraints on the minimal supergravity model from the b->s+\gamma decay are studied. A large domain in the parameter space for the model satisfies the CLEO bound, BR(b->s+\gamma)<5.4X10^{-4}. However, the allowed domain is expected to diminish significantly with an improved bound on this decay. The dependence of the b->s+\gamma branching ratio on various parameters is studied in detail. It is found that, for A_t<0 and the top quark mass within the vicinity of the center of the CDF value, m_t^{pole}=174\pm17 GeV, there exists only a small allowed domain because the light stop is tachyonic for most of the parameter space. A similar phenomenon exists for a lighter top and A_t negative when the GUT coupling constant is slightly reduced. For A_t>0, however, the branching ratio is much less sensitive to small changes in m_t, and \alpha_G.Comment: 12 pages, plain tex file, three figures avaliable upon request, CTP-TAMU-03/94, NUB-TH.7316/94, and CERN-TH.3092/9

    Megasatellites: a peculiar class of giant minisatellites in genes involved in cell adhesion and pathogenicity in Candida glabrata

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    Minisatellites are DNA tandem repeats that are found in all sequenced genomes. In the yeast Saccharomyces cerevisiae, they are frequently encountered in genes encoding cell wall proteins. Minisatellites present in the completely sequenced genome of the pathogenic yeast Candida glabrata were similarly analyzed, and two new types of minisatellites were discovered: minisatellites that are composed of two different intermingled repeats (called compound minisatellites), and minisatellites containing unusually long repeated motifs (126–429 bp). These long repeat minisatellites may reach unusual length for such elements (up to 10 kb). Due to these peculiar properties, they have been named ‘megasatellites’. They are found essentially in genes involved in cell–cell adhesion, and could therefore be involved in the ability of this opportunistic pathogen to colonize the human host. In addition to megasatellites, found in large paralogous gene families, there are 93 minisatellites with simple shorter motifs, comparable to those found in S. cerevisiae. Most of the time, these minisatellites are not conserved between C. glabrata and S. cerevisiae, although their host genes are well conserved, raising the question of an active mechanism creating minisatellites de novo in hemiascomycetes

    Effects of Cannabidiol on exercise physiology and bioenergetics : a randomised controlled pilot trial

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    Background: Cannabidiol (CBD) has demonstrated anti-inflammatory, analgesic, anxiolytic and neuroprotective effects that have the potential to benefit athletes. This pilot study investigated the effects of acute, oral CBD treatment on physiological and psychological responses to aerobic exercise to determine its practical utility within the sporting context. Methods: On two occasions, nine endurance-trained males (mean±SD V̇O2max: 57.4±4.0 mL·min−1 ·kg−1 ) ran for 60 min at a fixed intensity (70% V̇O2max) (RUN 1) before completing an incremental run to exhaustion (RUN 2). Participants received CBD (300 mg; oral) or placebo 1.5 h before exercise in a randomised, double-blind design. Respiratory gases (V̇O2), respiratory exchange ratio (RER), heart rate (HR), blood glucose (BG) and lactate (BL) concentrations, and ratings of perceived exertion (RPE) and pleasure–displeasure were measured at three timepoints (T1–3) during RUN 1. V̇O2max, RERmax, HRmax and time to exhaustion (TTE) were recorded during RUN 2. Venous blood was drawn at Baseline, Pre- and Post-RUN 1, Post-RUN 2 and 1 h Post-RUN 2. Data were synthesised using Cohen’s dz effect sizes and 85% confidence intervals (CIs). Effects were considered worthy of further investigation if the 85% CI included±0.5 but not zero. Results: CBD appeared to increase V̇O2 (T2:+38±48 mL·min−1, dz: 0.25–1.35), ratings of pleasure (T1:+0.7±0.9, dz: 0.22–1.32; T2:+0.8±1.1, dz: 0.17–1.25) and BL (T2:+3.3±6.4 mmol·L−1, dz:>0.00–1.03) during RUN 1 compared to placebo. No differences in HR, RPE, BG or RER were observed between treatments. CBD appeared to increase V̇O2max (+119±206 mL·min−1, dz: 0.06–1.10) and RERmax (+0.04±0.05 dz: 0.24–1.34) during RUN 2 compared to placebo. No differences in TTE or HRmax were observed between treatments. Exercise increased serum interleukin (IL)-6, IL-1β, tumour necrosis factor-α, lipopolysaccharide and myoglobin concentrations (i.e. Baseline vs. Post-RUN 1, Post-RUN 2 and/or 1-h Post-RUN 2, p’s<0.05). However, the changes were small, making it difficult to reliably evaluate the effect of CBD, where an effect appeared to be present. Plasma concentrations of the endogenous cannabinoid, anandamide (AEA), increased Post-RUN 1 and Post-RUN 2, relative to Baseline and Pre-RUN 1 (p’s<0.05). CBD appeared to reduce AEA concentrations Post-RUN 2, compared to placebo (−0.95±0.64 pmol·mL−1, dz: −2.19, −0.79). Conclusion: CBD appears to alter some key physiological and psychological responses to aerobic exercise without impairing performance. Larger studies are required to confirm and better understand these preliminary findings
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