1,032 research outputs found
On Gravitino properties in a Conformal Supergravity Model
In the context of a conformal Supergravity (SUGRA) model in the Einstein
frame, in which the (next to) minimal supersymmetric standard model can
embedded naturally to produce chaotic inflation scenarios, we study properties
of gravitino in the cases where it is stable or unstable. In the latter case,
we demonstrate that for large dilaton scale factors there is an enhanced
magnitude of the gravitino width, when it decays to neutralino dark matter, as
compared with the standard SUGRA case. In this context, we discuss the
associated consequences as far as Big Bang Nucleosynthesis constraints and
avoidance of gravitino overproduction are concerned.Comment: 7 pages latex, two eps figures incorporate
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Synthesis of accelerograms compatible with the Chinese GB 50011-2001 design spectrum via harmonic wavelets: artificial and historic records
A versatile approach is employed to generate artificial accelerograms which satisfy the compatibility criteria prescribed by the Chinese aseismic code provisions GB 50011-2001. In particular, a frequency dependent peak factor derived by means of appropriate Monte Carlo analyses is introduced to relate the GB 50011-2001 design spectrum to a parametrically defined evolutionary power spectrum (EPS). Special attention is given to the definition of the frequency content of the EPS in order to accommodate the mathematical form of the aforementioned design spectrum. Further, a one-to-one relationship is established between the parameter controlling the time-varying intensity of the EPS and the effective strong ground motion duration. Subsequently, an efficient auto-regressive moving-average (ARMA) filtering technique is utilized to generate ensembles of non-stationary artificial accelerograms whose average response spectrum is in a close agreement with the considered design spectrum. Furthermore, a harmonic wavelet based iterative scheme is adopted to modify these artificial signals so that a close matching of the signalsâ response spectra with the GB 50011-2001 design spectrum is achieved on an individual basis. This is also done for field recorded accelerograms pertaining to the May, 2008 Wenchuan seismic event. In the process, zero-phase high-pass filtering is performed to accomplish proper baseline correction of the acquired spectrum compatible artificial and field accelerograms. Numerical results are given in a tabulated format to expedite their use in practice
Proteomic identification and characterization of hepatic glyoxalase 1 dysregulation in non-alcoholic fatty liver disease
Background: Non-alcoholic fatty liver disease (NAFLD) is the most common liver disease worldwide. However, its
molecular pathogenesis is incompletely characterized and clinical biomarkers remain scarce. The aims of these
experiments were to identify and characterize liver protein alterations in an animal model of early, diet-related,
liver injury and to assess novel candidate biomarkers in NAFLD patients.
Methods: Liver membrane and cytosolic protein fractions from high fat fed apolipoprotein E knockout (ApoEâ/â)
animals were analyzed by quantitative proteomics, utilizing isobaric tags for relative and absolute quantitation
(iTRAQ) combined with nano-liquid chromatography and tandem mass spectrometry (nLC-MS/MS). Differential
protein expression was confirmed independently by immunoblotting and immunohistochemistry in both murine
tissue and biopsies from paediatric NAFLD patients. Candidate biomarkers were analyzed by enzyme-linked
immunosorbent assay in serum from adult NAFLD patients.
Results: Through proteomic profiling, we identified decreased expression of hepatic glyoxalase 1 (GLO1) in a
murine model. GLO1 protein expression was also found altered in tissue biopsies from paediatric NAFLD patients. In
vitro experiments demonstrated that, in response to lipid loading in hepatocytes, GLO1 is first hyperacetylated then
ubiquitinated and degraded, leading to an increase in reactive methylglyoxal. In a cohort of 59 biopsy-confirmed adult
NAFLD patients, increased serum levels of the primary methylglyoxal-derived advanced glycation endproduct,
hydroimidazolone (MG-H1) were significantly correlated with body mass index (r = 0.520, p < 0.0001).
Conclusion: Collectively these results demonstrate the dysregulation of GLO1 in NAFLD and implicate the
acetylation-ubquitination degradation pathway as the functional mechanism. Further investigation of the role
of GLO1 in the molecular pathogenesis of NAFLD is warranted.
Keywords: Non-alcoholic fatty liver disease, Glyoxalase, Methylglyoxal, Proteomics, iTRA
Update on the Direct Detection of Supersymmetric Dark Matter
We compare updated predictions for the elastic scattering of supersymmetric
neutralino dark matter with the improved experimental upper limit recently
published by CDMS II. We take into account the possibility that the \pi-nucleon
\Sigma term may be somewhat larger than was previously considered plausible, as
may be supported by the masses of exotic baryons reported recently. We also
incorporate the new central value of m_t, which affects indirectly constraints
on the supersymmetric parameter space, for example via calculations of the
relic density. Even if a large value of \Sigma is assumed, the CDMS II data
currently exclude only small parts of the parameter space in the constrained
MSSM (CMSSM) with universal soft supersymmetry-breaking Higgs, squark and
slepton masses. None of the previously-proposed CMSSM benchmark scenarios is
excluded for any value of \Sigma, and the CDMS II data do not impinge on the
domains of the CMSSM parameter space favoured at the 90 % confidence level in a
recent likelihood analysis. However, some models with non-universal Higgs,
squark and slepton masses and neutralino masses \lappeq 700 GeV are excluded by
the CDMS II data.Comment: 25 pages, 28 eps figure
Neutralino Dark Matter Elastic Scattering in a Flat and Accelerating Universe
In SUGRA inspired supersymmetric models with universal boundary conditions
for the soft masses, the scalar cross section for the elastic
neutralino--nucleon scattering is in general several orders of magnitude below
the sensitivity of current experiments. For large and low
values, the theoretically predicted can
approach the sensitivity of these experiments () being at
the same time in agreement with recent cosmological data, which impose severe
restrictions on the CDM relic density, and with accelerator experiments which
put lower bounds on sparticle and Higgs boson masses. Further improvement of
the sensitivity of DAMA and CDMS experiments will probe the large
region of the parameter space in the vicinity of the boundaries of the
parameter space allowed by chargino and Higgs searches.Comment: 15 pages, 9 figures. A note added; version to appear in MPL
Partial wave treatment of Supersymmetric Dark Matter in the presence of CP - violation
We present an improved partial wave analysis of the dominant LSP annihilation
channel to a fermion-antifermion pair which avoids the non-relativistic
expansion being therefore applicable near thresholds and poles. The method we
develop allows of contributions of any partial wave in the total angular
momentum J in contrast to partial wave analyses in terms of the orbital angular
momentum L of the initial state, which is usually truncated to p-waves, and
yields very accurate results. The method is formulated in such a way as to
allow easy handling of CP-violating phases residing in supersymmetric
parameters. We apply this refined partial wave technique in order to calculate
the neutralino relic density in the constrained MSSM (CMSSM) in the presence of
CP-violating terms occurring in the Higgs - mixing parameter \mu and trilinear
A coupling for large tanb. The inclusion of CP-violating phases in mu and A
does not upset significantly the picture and the annihilation of the LSP's to a
b b_bar, through Higgs exchange, is still the dominant mechanism in obtaining
cosmologically acceptable neutralino relic densities in regions far from the
stau-coannihilation and the `focus point'. Significant changes can occur if we
allow for phases in the gaugino masses and in particular the gluino mass.Comment: 23 pages LaTeX, 10 eps figures, version to appear in PR
Neutrino Fluxes from CMSSM LSP Annihilations in the Sun
We evaluate the neutrino fluxes to be expected from neutralino LSP
annihilations inside the Sun, within the minimal supersymmetric extension of
the Standard Model with supersymmetry-breaking scalar and gaugino masses
constrained to be universal at the GUT scale (the CMSSM). We find that there
are large regions of typical CMSSM planes where the LSP
density inside the Sun is not in equilibrium, so that the annihilation rate may
be far below the capture rate. We show that neutrino fluxes are dependent on
the solar model at the 20% level, and adopt the AGSS09 model of Serenelli et
al. for our detailed studies. We find that there are large regions of the CMSSM
planes where the capture rate is not dominated by
spin-dependent LSP-proton scattering, e.g., at large along the CMSSM
coannihilation strip. We calculate neutrino fluxes above various threshold
energies for points along the coannihilation/rapid-annihilation and focus-point
strips where the CMSSM yields the correct cosmological relic density for
tan(beta) = 10 and 55 for > 0, exploring their sensitivities to
uncertainties in the spin-dependent and -independent scattering matrix
elements. We also present detailed neutrino spectra for four benchmark models
that illustrate generic possibilities within the CMSSM. Scanning the
cosmologically-favored parts of the parameter space of the CMSSM, we find that
the IceCube/DeepCore detector can probe at best only parts of this parameter
space, notably the focus-point region and possibly also at the low-mass tip of
the coannihilation strip.Comment: 32 pages, 13 figures. v2: updated/expanded discussion of
IceCube/DeepCor
Adolescent C57BL/6J Mice Show Elevated Alcohol Intake, but Reduced Taste Aversion, as Compared to Adult Mice: A Potential Behavioral Mechanism for Binge Drinking: ELEVATED ALCOHOL INTAKE IN ADOLESCENCE
Binge alcohol drinking during adolescence is a serious health problem which may increase future risk of an alcohol use disorder. Although there are several different procedures by which to preclinically model binge-like alcohol intake, limited-access procedures offer the advantage of achieving high voluntary alcohol intake and pharmacologically relevant blood alcohol concentrations (BACs). Therefore, in the current study, developmental differences in binge-like alcohol drinking using a limited-access cycling procedure were examined. In addition, as alcohol drinking has been negatively correlated with sensitivity to the aversive properties of alcohol, we examined developmental differences in sensitivity to an alcohol-induced conditioned taste aversion (CTA)
Refining the predictions of supersymmetric CP-violating models: A top-down approach
We explore in detail the consequences of the CP-violating phases residing in
the supersymmetric and soft SUSY breaking parameters in the approximation that
family flavour mixings are ignored. We allow for non-universal boundary
conditions and in such a consideration the model is described by twelve
independent CP-violating phases and one angle which misaligns the vacuum
expectation values (VEVs) of the Higgs scalars. We run two-loop renormalization
group equations (RGEs), for all parameters involved, including phases, and we
properly treat the minimization conditions using the one-loop effective
potential with CP-violating phases included. We show that the two-loop running
of phases may induce sizable effects for the electric dipole moments (EDMs)
that are absent in the one-loop RGE analysis. Also important corrections to the
EDMs are induced by the Higgs VEVs misalignment angle which are sizable in the
large tanb region. Scanning the available parameter space we seek regions
compatible with accelerator and cosmological data with emphasis on rapid
neutralino annihilations through a Higgs resonance. It is shown that large
CP-violating phases, as required in Baryogenesis scenarios, can be tuned to
obtain agreement with WMAP3 cold dark matter constraints, EDMs and all
available accelerator data, in extended regions of the parameter space which
may be accessible to LHC.Comment: 41 pages, 22 eps figures. A reference added and a typo corrected;
version to appear in JHE
Spatial variability of precipitation regimes over Turkey
Turkish annual precipitation regimes are analysed to provide large-scale perspective and redefine precipitation regions. Monthly total precipitation data are employed for 107 stations (1963â2002). Precipitation regime shape (seasonality) and magnitude (size) are classified using a novel multivariate methodology. Six shape and five magnitude classes are identified, which exhibit clear spatial structure. A composite (shape and magnitude) regime classification reveals dominant controls on spatial variability of precipitation. Intra-annual timing and magnitude of precipitation is highly variable due to seasonal shifts in Polar and Subtropical zones and physiographic factors. Nonetheless, the classification methodology is shown to be a powerful tool that identifies physically-interpretable precipitation regions: (1) coastal regimes for Marmara, coastal Aegean, Mediterranean and Black Sea; (2) transitional regimes in continental Aegean and Southeast Anatolia; and (3) inland regimes across central and Eastern Anatolia. This research has practical implications for understanding water resources, which are under ever growing pressure in Turkey
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