282 research outputs found
Semileptonic and Decays and the Chiral Anomaly at One-loop
We calculate the corrections to the anomalous form factors appearing
in , and decays in
Chiral Perturbation Theory. The relevant dimension terms of the lagrangian
are evaluated assuming their saturation by the vector meson contribution.Comment: 10 pages of LaTeX (+3 figures available on request
Two-fluid barotropic models for powder-snow avalanche flows
14 pages, 1 figure. Accepted to Springer series "Notes on Numerical Fluid Mechanics and Multidisciplinary Design". Other authors papers can be downloaded at http://www.lama.univ-savoie.fr/~dutykh/International audienceIn the present study we discuss several modeling issues of powder-snow avalanche flows. We take a two-fluid modeling paradigm. For the sake of simplicity, we will restrict our attention to barotropic equations. We begin the exposition by a compressible model with two velocities for each fluid. However, this model may become non-hyperbolic and thus, represents serious challenges for numerical methods. To overcome these issues, we derive a single velocity model as a result of a relaxation process. This model can be easily shown to be hyperbolic for any reasonable equation of state. Finally, an incompressible limit of this model is derived
Loading and unloading of sedimentary basins: the effect of rheological hysteresis
We present a model for the study of the effect of rheological hysteresis on compaction in sedimentary basins, when surface loading and unloading occurs. When compaction is slow (sedimentation rate is large and/or permeability is small), the hysteresis has little effect on the basal compaction layer, but in the more realistic case where compaction is fast (i.e., sedimentation is slow and/or permeability is large), surface unloading leads to downward propagation of a decompaction front, across which the vertical porosity gradient jumps, while subsequent surface reloading leads to downward propagation of a discontinuity in porosity, despite the fact that the porosity is governed by a diffusive equation of Richards type
The Chiral Anomaly in Non-Leptonic Weak Interactions
The interplay between the chiral anomaly and the non-leptonic weak
Hamiltonian is studied. The structure of the corresponding effective Lagrangian
of odd intrinsic parity is established. It is shown that the factorizable
contributions (leading in ) to that Lagrangian can be calculated without
free parameters. As a first application, the decay K^+ \ra \pi^+ \pi^0 \gamma
is investigated.Comment: 10 pages, LaTe
Odd-intrinsic-parity processes within the Resonance Effective Theory of QCD
We analyse the most general odd-intrinsic-parity effective Lagrangian of QCD
valid for processes involving one pseudoscalar with vector mesons described in
terms of antisymmetric tensor fields. Substantial information on the
odd-intrinsic-parity couplings is obtained by constructing the
vector-vector-pseudoscalar Green's three-point function, at leading order in
1/Nc, and demanding that its short-distance behaviour matches the corresponding
OPE result. The QCD constraints thus enforced allow us to predict the decay
amplitude omega -> pion gamma, and the O(p^6) corrections to pion -> gamma
gamma. Noteworthy consequences concerning the vector meson dominance assumption
in the decay omega -> 3 pions are also extracted from the previous analysis.Comment: 20 pages, 4 figure
A missense mutation in Ehd1 associated with defective spermatogenesis and male infertility
Normal function of the C-terminal Eps15 homology domain-containing protein 1 (EHD1) has previously been associated with endocytic vesicle trafficking, shaping of intracellular membranes, and ciliogenesis. We recently identified an autosomal recessive missense mutation c.1192C>T (p.R398W) of EHD1 in patients who had low molecular weight proteinuria (0.7–2.1 g/d) and high-frequency hearing loss. It was already known from Ehd1 knockout mice that inactivation of Ehd1 can lead to male infertility. However, the exact role of the EHD1 protein and its p.R398W mutant during spermatogenesis remained still unclear. Here, we report the testicular phenotype of a knockin mouse model carrying the p.R398W mutation in the EHD1 protein. Male homozygous knockin mice were infertile, whereas the mutation had no effect on female fertility. Testes and epididymes were significantly reduced in size and weight. The testicular epithelium appeared profoundly damaged and had a disorganized architecture. The composition of developing cell types was altered. Malformed acrosomes covered underdeveloped and misshaped sperm heads. In the sperm tail, midpieces were largely missing indicating disturbed assembly of the sperm tail. Defective structures, i.e., nuclei, acrosomes, and sperm tail midpieces, were observed in large vacuoles scattered throughout the epithelium. Interestingly, cilia formation itself did not appear to be affected, as the axoneme and other parts of the sperm tails except the midpieces appeared to be intact. In wildtype mice, EHD1 co-localized with acrosomal granules on round spermatids, suggesting a role of the EHD1 protein during acrosomal development. Wildtype EHD1 also co-localized with the VPS35 component of the retromer complex, whereas the p.R398W mutant did not. The testicular pathologies appeared very early during the first spermatogenic wave in young mice (starting at 14 dpp) and tubular destruction worsened with age. Taken together, EHD1 plays an important and probably multifaceted role in spermatogenesis in mice. Therefore, EHD1 may also be a hitherto underestimated infertility gene in humans
Anomalies and WZW-term of two-flavour QCD
The U(2)_R x U(2)_L symmetry of QCD with two massless flavours is subject to
anomalies which affect correlation functions involving the singlet currents
A^0_\mu or V^0_\mu. These are relevant for pion-photon interactions, because -
for two flavours - the electromagnetic current contains a singlet piece. We
give the effective Lagrangian required for the corresponding low energy
analysis to next-to-leading order, without invoking an expansion in the mass of
the strange quark. In particular, the Wess-Zumino-Witten term that accounts for
the two-flavour anomalies within the effective theory is written down in closed
form.Comment: 17 pages, 1 figur
Clinical and familial profile of bipolar disorder with and without obsessive-compulsive disorder: an Indian study
Circuit-wide Transcriptional Profiling Reveals Brain Region-Specific Gene Networks Regulating Depression Susceptibility
Depression is a complex, heterogeneous disorder and a leading contributor to the global burden of disease. Most previous research has focused on individual brain regions and genes contributing to depression. However, emerging evidence in humans and animal models suggests that dysregulated circuit function and gene expression across multiple brain regions drive depressive phenotypes. Here we performed RNA-sequencing on 4 brain regions from control animals and those susceptible or resilient to chronic social defeat stress at multiple time points. We employed an integrative network biology approach to identify transcriptional networks and key driver genes that regulate susceptibility to depressive-like symptoms. Further, we validated in vivo several key drivers and their associated transcriptional networks that regulate depression susceptibility and confirmed their functional significance at the levels of gene transcription, synaptic regulation and behavior. Our study reveals novel transcriptional networks that control stress susceptibility and offers fundamentally new leads for antidepressant drug discovery
Comparatistica sul filo dell'orizzonte
Among the literary disciplines, the comparatism is that which, over time, is generally more affected by the dominant moods outside the academic sphere. Giving rise to the oscillations of consensus, sometimes attributed to the absence of a methodological status that is at least defined by representing a language and a nation (as is the case with national literatures), comparatism presupposes the support of a universalist or at least pro-European thought, perpetuating, in the translatio studiorum, the humanistic conception of literature as culture and as knowledge
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