1,267 research outputs found

    Radiative Mechanism to Light Fermion Masses in the MSSM

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    In a previous work we have showed that the Z2â€Č{\cal Z}_{2}^{\prime} Symmetry, imply that the light fermions, the electron and the quarks, u,du,d and ss, get their masses only at one loop level. Here, we considere the more general hypothesis for flavour mixing in the sfermion sector in the MSSM. Then, we present our results to the masses of these light fermions and as a final result we can explain why the ss quark is heavier than the u,du,d quarks. This mechanism is in agrement with the experimental constraint on the sfermion's masses values.Comment: 22 pages, 8 figures, TeX mistakes corrected, accepted for publication in JHE

    Dynamic space utilization for lame and non-lame gestating sows estimated by the lying-standing sequence

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    peer-reviewedThe objective of this study was to estimate the dynamic space utilization for lame and non-lame sows using their lying-standing postural sequence profile. Eighty-five sows (parity 0.9 ± 1.14; range 0 to 4) were used. Sows were moved to a pen on 30, 60 and 90 days of gestation and a ceiling mounted camera was installed above the pen to record one lying-standing event per sow. Observations ceased when the sow lied and stood, or 2.5 h elapsed from recording commencement. Additionally, each sow was evaluated for walking lameness while moving from their gestation stall to the pen. Still frames were captured from the sows’ lying and standing sequences and were combined into a single image and measured by counting pixels from contouring the sows’ body (CONTOUR), overlaying a grid on the sow image and counting any square including any part of the sow (FULL-GRID) and only counting any square that was half full or more (HALF-GRID). The space utilized while turning around was calculated by measuring the sows’ length from snout to the base of the tail and using that length as the diameter of a circle (D-PIVOT), or as the radius of a circle (R-PIVOT). Parity was re-classified as 0, 1, and 2+. There were no observed differences in the dynamic space utilized to lie, stand or turn around between lame and non-lame sows (P > 0.05). On average, sows used 1.2 ± 0.47 m2 to lie and 1.3 ± 0.46 m2 to stand. There was no difference between the CONTOUR and HALF-GRID methods (P > 0.05); however, using the FULL-GRID sows required 0.3 m2 more floor area to lie and stand compared with the other measuring methods (P < 0.05). Space used to turn around differed between measuring method (P < 0.05). Sows required 1.9 ± 0.18 m2 for D-PIVOT and 7.3 ± 0.18 m2 for R-PIVOT to turn around. Space utilized to lie-down and stand-up increased as gestation progressed (P < 0.05). Under the conditions of this study, lameness did not influence dynamic space utilization; however, lameness recorded was relatively mild and might not have been sufficiently severe to significantly affect the results. These results could be important in decision-making process for housing specifications regarding US sow gestation housing

    Psychiatric comorbidity in individuals with bullous pemphigoid and all bullous disorders in the Danish national registers

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    BACKGROUND: Bullous pemphigoid (BP) is an autoimmune blistering skin disease that takes a profound physical and mental toll on those affected. The aim of the study was to investigate the bidirectional association between BP and all bullous disorders (ABD) with a broad array of psychiatric disorders, exploring the influence of prescribed medications. METHODS: This nationwide, register-based cohort study encompassed 6,470,450 individuals born in Denmark and alive from 1994 to 2016. The hazard ratios (HRs) of a subsequent psychiatric disorder in patients with BP/ABD and the reverse exposure and outcome were evaluated. RESULTS: Several psychiatric disorders were associated with increased risk of subsequent BP (4.18-fold for intellectual disorders, 2.32-fold for substance use disorders, 2.01-fold for schizophrenia and personality disorders, 1.92-1.85-1.49-fold increased risk for organic disorders, neurotic and mood disorders), independent of psychiatric medications. The association between BP and subsequent psychiatric disorders was not significant after adjusting for BP medications, except for organic disorders (HR 1.27, CI 1.04-1.54). Similar results emerged with ABD. CONCLUSION: Psychiatric disorders increase the risk of a subsequent diagnosis of BP/ABD independent of medications, whereas medications used for the treatment of BP/ABD appear to account for the subsequent onset of psychiatric disorders. Clinically, an integrated approach attending to both dermatological and psychiatric symptoms is recommended, and dermatologists should remain vigilant for early symptoms of psychiatric disorders to decrease mental health comorbidity

    Cosmic Acceleration in Brans-Dicke Cosmology

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    We consider Brans-Dicke theory with a self-interacting potential in Einstein conformal frame. We show that an accelerating expansion is possible in a spatially flat universe for large values of the Brans-Dicke parameter consistent with local gravity experiments.Comment: 10 Pages, 3 figures, To appear in General Relativity and Gravitatio

    Tensor-scalar gravity and binary-pulsar experiments

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    Some recently discovered nonperturbative strong-field effects in tensor-scalar theories of gravitation are interpreted as a scalar analog of ferromagnetism: "spontaneous scalarization". This phenomenon leads to very significant deviations from general relativity in conditions involving strong gravitational fields, notably binary-pulsar experiments. Contrary to solar-system experiments, these deviations do not necessarily vanish when the weak-field scalar coupling tends to zero. We compute the scalar "form factors" measuring these deviations, and notably a parameter entering the pulsar timing observable gamma through scalar-field-induced variations of the inertia moment of the pulsar. An exploratory investigation of the confrontation between tensor-scalar theories and binary-pulsar experiments shows that nonperturbative scalar field effects are already very tightly constrained by published data on three binary-pulsar systems. We contrast the probing power of pulsar experiments with that of solar-system ones by plotting the regions they exclude in a generic two-dimensional plane of tensor-scalar theories.Comment: 35 pages, REVTeX 3.0, uses epsf.tex to include 9 Postscript figure

    Bounding Helly numbers via Betti numbers

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    We show that very weak topological assumptions are enough to ensure the existence of a Helly-type theorem. More precisely, we show that for any non-negative integers bb and dd there exists an integer h(b,d)h(b,d) such that the following holds. If F\mathcal F is a finite family of subsets of Rd\mathbb R^d such that ÎČ~i(⋂G)≀b\tilde\beta_i\left(\bigcap\mathcal G\right) \le b for any G⊊F\mathcal G \subsetneq \mathcal F and every 0≀i≀⌈d/2⌉−10 \le i \le \lceil d/2 \rceil-1 then F\mathcal F has Helly number at most h(b,d)h(b,d). Here ÎČ~i\tilde\beta_i denotes the reduced Z2\mathbb Z_2-Betti numbers (with singular homology). These topological conditions are sharp: not controlling any of these ⌈d/2⌉\lceil d/2 \rceil first Betti numbers allow for families with unbounded Helly number. Our proofs combine homological non-embeddability results with a Ramsey-based approach to build, given an arbitrary simplicial complex KK, some well-behaved chain map C∗(K)→C∗(Rd)C_*(K) \to C_*(\mathbb R^d).Comment: 29 pages, 8 figure

    Flavor changing Z-decays from scalar interactions at a Giga-Z Linear Collider

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    The flavor changing decay Z -> d_I \bar{d}_J is investigated with special emphasis on the b \bar{s} final state. Various models for flavor violation are considered: two Higgs doublet models (2HDM's), supersymmetry (SUSY) with flavor violation in the up and down-type squark mass matrices and SUSY with flavor violation mediated by R-parity-violating interaction. We find that, within the SUSY scenarios for flavor violation, the branching ratio for the decay Z -> b \bar{s} can reach 10^{-6} for large \tan\beta values, while the typical size for this branching ratio in the 2HDM's considered is about two orders of magnitudes smaller at best. Thus, flavor changing SUSY signatures in radiative Z decays such as Z -> b \bar{s} may be accessible to future ``Z factories'' such as a Giga-Z version of the TESLA design.Comment: 27 pages, 15 figures, REVTeX4. A new section added and a few minor corrections were made in the tex

    Holographic Dark Energy Model and Scalar-Tensor Theories

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    We study the holographic dark energy model in a generalized scalar tensor theory. In a universe filled with cold dark matter and dark energy, the effect of potential of the scalar field is investigated in the equation of state parameter. We show that for a various types of potentials, the equation of state parameter is negative and transition from deceleration to acceleration expansion of the universe is possible.Comment: 11 pages, no figure. To appear in General Relativity and Gravitatio

    Antibody and delayed-type hypersensitivity responses to Ochrobactrum anthropi cytosolic and outer membrane antigens in infections by smooth and rough Brucella spp

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    Immunological cross-reactions between Brucella spp. and Ochrobactrum anthropi were investigated in animals and humans naturally infected by Brucella spp. and in experimentally infected rams (Brucella ovis infected), rabbits (Brucella melitensis infected), and mice (B. melitensis and Brucella abortus infected). In the animals tested, O. anthropi cytosolic proteins evoked a delayed-type hypersensitivity reaction of a frequency and intensity similar to that observed with B. melitensis brucellin. O. anthropi cytosolic proteins also reacted in gel precipitation tests with antibodies in sera from Brucella natural hosts with a frequency similar to that observed with B. melitensis proteins, and absorption experiments and immunoblotting showed antibodies to both Brucella-specific proteins and proteins common to Brucella and O. anthropi. No antibodies to O. anthropi cytosolic proteins were detected in the sera of Brucella-free hosts. Immunoblotting with sera of Brucella-infected sheep and goats showed immunoglobulin G (IgG) to Brucella group 3 outer membrane proteins and to O. anthropi proteins of similar molecular weight. No IgG to the O-specific polysaccharide of O. anthropi lipopolysaccharide was detected in the sera of Brucella-infected hosts. The sera of sheep, goats, and rabbits infected with B. melitensis contained IgG to O. anthropi rough lipopolysaccharide and lipid A, and B. ovis and O. anthropi rough lipopolysaccharides showed equal reactivities with IgG in the sera of B. ovis-infected rams. The findings show that the immunoresponse of Brucella-infected hosts to protein antigens is not necessarily specific for brucellae and suggest that the presence of O. anthropi or some related bacteria explains the previously described reactivities to Brucella rough lipopolysaccharide and outer membrane proteins in healthy animals

    Grain Surface Models and Data for Astrochemistry

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    AbstractThe cross-disciplinary field of astrochemistry exists to understand the formation, destruction, and survival of molecules in astrophysical environments. Molecules in space are synthesized via a large variety of gas-phase reactions, and reactions on dust-grain surfaces, where the surface acts as a catalyst. A broad consensus has been reached in the astrochemistry community on how to suitably treat gas-phase processes in models, and also on how to present the necessary reaction data in databases; however, no such consensus has yet been reached for grain-surface processes. A team of ∌25 experts covering observational, laboratory and theoretical (astro)chemistry met in summer of 2014 at the Lorentz Center in Leiden with the aim to provide solutions for this problem and to review the current state-of-the-art of grain surface models, both in terms of technical implementation into models as well as the most up-to-date information available from experiments and chemical computations. This review builds on the results of this workshop and gives an outlook for future directions
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