2,975 research outputs found
Flavor Changing Higgs Decays in Supersymmetry with Minimal Flavor Violation
We study the flavor changing neutral current decays of the MSSM Higgs bosons
into strange and bottom quarks. We focus on a scenario of minimum flavor
violation here, namely only that induced by the CKM matrix. Taking into account
constraint from , as well as experimental
constraints on the MSSM spectrum, we show that the branching ratio of and combined, for being either one of
the CP even Higgs states, can reach the order - for large
, large , and large . The result illustrates the
significance of minimal flavor violation scenario which can induce competitive
branching fraction for flavor changing Higgs decays. This can be compared with
the previous studies where similar branching fraction has been reported, but
with additional sources of flavor violations in squark mass matrices. We also
discuss some basic features of the flavor violating decays in the generic case.Comment: 16 pages on Revtex, with 5 figures from 10 eps files incorporated;
discussion on issues related more precise calculations elaborated;
proof-edited version to appear in Phys. Lett.
Eight months of continuous positive airway pressure (CPAP) decrease tumor necrosis factor alpha (TNFA) in men with obstructive sleep apnea syndrome
Objectives: The aim of this study was to assess serum tumor necrosis factor alpha (TNFA) concentrations 8months of continuous positive airway pressure (CPAP) therapy. Design: This study used prospective, observational clinical trial. Patients: Sixty-six patients with newly diagnosed sleep apnea syndrome (12 women, 54 men), age 52.3 ± 9.8 (mean ± SD) with a body mass index of 29.7 ± 4.4 and an apnea-hypopnea index of 39.7 ± 26.8, were studied. Intervention: CPAP was administered for a mean of 7.8 ± 1.3months. Measurements and results: TNFA concentrations using an ultrasensitive ELISA assay at baseline and follow-up. TNFA decreased in men with high (5.2 ± 1.7h/night, −0.46 ± 1.1ng/l, p = 0.001) and with low (2.5 ± 1.0h/night −0.63 ± 0.77ng/l, p = 0.001) adherence but not in women. Average number of hours of CPAP use correlated positively with delta TNFA (R 2 0.08, p = 0.04) Conclusion: Long-term CPAP positively affects TNFA even in men with poor adherence to CPA
Наукове свiторозумiння — Вiденський гурток
Rudolf Carnap, Hans Hahn, Otto Neurath. Wissenschaftliche Weltauffassung. Der Wiener Kreis. Wien: Artur Wolf Verlag, 1929. Rudolf Carnap, Hans Hahn, Otto Neurath. Wissenschaftliche Weltauffassung. Der Wiener Kreis. Wien: Artur Wolf Verlag, 1929
Revisiting Fara: Comparison of merged prospection results of diverse magnetometers with the earliest excavations in ancient Suruppak from 120 years ago
Ancient Suruppak, today Fara, was one of the major Sumerian cities in Mesopotamia. It was situated along one of the ancient watercourses of the Euphrates River. Findings date it back to the Jemdet Nasr period around 3000 bc with a continuous occupation until the end of the Ur III period around 2000 bc. Fara was first explored and excavated by the Deutsche Orient-Gesellschaft in the years 1902 and 1903 under the direction of Walter Andrae. Multiple excavation trenches with lengths up to 900 m transect the 1 km(2) wide mound and are still visible today which enables us to georeference the excavation maps. Today, the 2.2 km(2) wide archaeological area is dry and without any vegetation. Thousands of deep looting pits are covering the majority of mound which not only destroyed its upper metres but also challenge the application of geophysical prospection methods and their interpretation. The magnetometer prospecting of selected areas on and around the mound was carried out with three devices, two total field magnetometers and one gradiometer. The individual survey areas were combined in post-processing by applying a high-pass filter on the total field data sets and multiplying the vertical gradiometer data sets by a factor of two. This approach provides visually uniform magnetograms, despite being obtained by different devices, which simplifies subsequent visual interpretation. These magnetograms enable us to review, and to extend the results of the old excavations. The comparison show a good correlation in accuracy to the old drawings and positive identification of the already excavated features with magnetometry. Highlights of the survey are the discovery of the city wall confirming its existence, the layout of a unique building complex in the centre of the mound, likely a temple, traces of canals inside the city and an evaluation of magnetometer prospection over a looted area
Clozapine modulates retinoid homeostasis in human brain and normalizes serum retinoic acid deficit in patients with schizophrenia
The atypical antipsychotic clozapine is one of the most potent drugs of its class, yet its precise mechanisms of action remain insufficiently understood. Recent evidence points toward the involvement of endogenous retinoic acid (RA) signaling in the pathophysiology of schizophrenia. Here we investigated whether clozapine may modulate RA-signaling. Effects of clozapine on the catabolism of all-trans RA (at-RA), the biologically most active metabolite of Vitamin A, were assessed in murine and human brain tissue and peripheral blood-derived mononuclear cells (PBMC). In patients with schizophrenia with and without clozapine treatment and matched healthy controls, at-RA serum levels and blood mRNA expression of retinoid-related genes in PBMCs were quantified. Clozapine and its metabolites potently inhibited RA catabolism at clinically relevant concentrations. In PBMC-derived microsomes, we found a large interindividual variability of the sensitivity toward the effects of clozapine. Furthermore, at-RA and retinol serum levels were significantly lower in patients with schizophrenia compared with matched healthy controls. Patients treated with clozapine exhibited significantly higher at-RA serum levels compared with patients treated with other antipsychotics, while retinol levels did not differ between treatment groups. Similarly, in patients without clozapine treatment, mRNA expression of RA-inducible targets CYP26A and STRA6, as well as at-RA/retinol ratio, were significantly reduced. In contrast, clozapine-treated patients did not differ from healthy controls in this regard. Our findings provide the first evidence for altered peripheral retinoid homeostasis in schizophrenia and suggest modulation of RA catabolism as a novel mechanism of action of clozapine, which may be useful in future antipsychotic drug development
The Peaks Formalism and the Formation of Cold Dark Matter Haloes
We use two cosmological simulations of structure formation to study the
conditions under which dark matter haloes emerge from the linear density field.
Our analysis focuses on matching sites of halo collapse to local density
maxima, or "peaks", in the initial conditions of the simulations and provides a
crucial test of the central ansatz of the peaks formalism. By identifying peaks
on a variety of smoothed, linearly extrapolated density fields we demonstrate
that as many as ~70% of well-resolved dark matter haloes form preferentially
near peaks whose characteristic masses are similar to that of the halo, with
more massive haloes showing a stronger tendency to reside near peaks initially.
We identify a small but significant fraction of haloes that appear to evolve
from peaks of substantially lower mass than that of the halo itself. We refer
to these as "peakless haloes" for convenience. By contrasting directly the
properties of these objects with the bulk of the proto-halo population we find
two clear differences: 1) their initial shapes are significantly flatter and
more elongated than the predominantly triaxial majority, and 2) they are, on
average, more strongly compressed by tidal forces associated with their
surrounding large scale structure. Using the two-point correlation function we
show that peakless haloes tend to emerge from highly clustered regions of the
initial density field implying that, at fixed mass, the accretion geometry and
mass accretion histories of haloes in highly clustered environments differ
significantly from those in the field. This may have important implications for
understanding the origin of the halo assembly bias, of galaxy properties in
dense environments and how environment affects the morphological transformation
of galaxies near groups and rich galaxy clusters.Comment: 13 pages, 11 figures, published in MNRA
Resting-state alterations in behavioral variant frontotemporal dementia are related to the distribution of monoamine and GABA neurotransmitter systems
Aside to clinical changes, behavioral variant frontotemporal dementia (bvFTD) is characterized by progressive structural and functional alterations in frontal and temporal regions. We examined if there is a selective vulnerability of specific neurotransmitter systems in bvFTD by evaluating the link between disease-related functional alterations and the spatial distribution of specific neurotransmitter systems and their underlying gene expression levels.Maps of fractional amplitude of low frequency fluctuations (fALFF) were derived as a measure of local activity from resting-state functional magnetic resonance imaging for 52 bvFTD patients (mean age = 61.5 ± 10.0 years; 14 female) and 22 healthy controls (HC) (mean age = 63.6 ± 11.9 years; 13 female). We tested if alterations of fALFF in patients co-localize with the non-pathological distribution of specific neurotransmitter systems and their coding mRNA gene expression. Further, we evaluated if the strength of co-localization is associated with the observed clinical symptoms.Patients displayed significantly reduced fALFF in fronto-temporal and fronto-parietal regions. These alterations co-localized with the distribution of serotonin (5-HT1b, 5-HT2a), dopamine (D2), and γ-aminobutyric acid (GABAa) receptors, the norepinephrine transporter (NET), and their encoding mRNA gene expression. The strength of co-localization with D2 and NET was associated with cognitive symptoms and disease severity of bvFTD.Local brain functional activity reductions in bvFTD followed the distribution of specific neurotransmitter systems indicating a selective vulnerability. These findings provide novel insight into the disease mechanisms underlying functional alterations. Our data-driven method opens the road to generate new hypotheses for pharmacological interventions in neurodegenerative diseases even beyond bvFTD
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