1,026 research outputs found
Genética de las proteínas de reserva del cotiledón en castaño (Castanea sativa Miller)
A first approximation to the inheritance of cotyledon storage proteins was studied in European sweet chestnut (Castanea sativa Mill.) by evaluating the offspring of a controlled cross between two local chestnut varieties (Corriente and Pilonga) from southern Spain. The analysis was carried out in 15 polymorphic bands corresponding to the albumin fraction of the storage proteins. The relationship between bands displayed one case of allelism and four of linkage. These results should be considered as the baseline of the genetics of these proteins and suggest that they could be useful for the evaluation of the genetic variability in chestnut.Se ha efectuado una primera aproximación a la genética de las proteínas de reserva del cotiledón en castaño (Castanea sativa Mill.). Para ello, se ha evaluado la progenie resultante del cruzamiento controlado entre dos variedades locales del sur de España (Corriente y Pilonga). El análisis se ha realizado en 15 bandas polimórficas correspondientes a la fracción albúmina de las proteínas de reserva. El estudio de la combinación entre bandas ha permitido identificar un caso de alelismo y cuatro de ligamiento. Estos resultados suponen una contribución al estudio de la genética de estas proteínas y sugieren que podrían ser una herramienta útil para la evaluación de la variabilidad genética del castaño
Super-extended noncommutative Landau problem and conformal symmetry
A supersymmetric spin-1/2 particle in the noncommutative plane, subject to an
arbitrary magnetic field, is considered, with particular attention paid to the
homogeneous case. The system has three different phases, depending on the
magnetic field. Due to supersymmetry, the boundary critical phase which
separates the sub- and super-critical cases can be viewed as a reduction to the
zero-energy eigensubspace. In the sub-critical phase the system is described by
the superextension of exotic Newton-Hooke symmetry, combined with the conformal
so(2,1) ~ su(1,1) symmetry; the latter is changed into so(3) ~ su(2) in the
super-critical phase. In the critical phase the spin degrees of freedom are
frozen and supersymmetry disappears.Comment: 12 pages, references added, published versio
Field Theoretical Quantum Effects on the Kerr Geometry
We study quantum aspects of the Einstein gravity with one time-like and one
space-like Killing vector commuting with each other. The theory is formulated
as a \coset nonlinear -model coupled to gravity. The quantum analysis
of the nonlinear -model part, which includes all the dynamical degrees
of freedom, can be carried out in a parallel way to ordinary nonlinear
-models in spite of the existence of an unusual coupling. This means
that we can investigate consistently the quantum properties of the Einstein
gravity, though we are limited to the fluctuations depending only on two
coordinates. We find the forms of the beta functions to all orders up to
numerical coefficients. Finally we consider the quantum effects of the
renormalization on the Kerr black hole as an example. It turns out that the
asymptotically flat region remains intact and stable, while, in a certain
approximation, it is shown that the inner geometry changes considerably however
small the quantum effects may be.Comment: 16 pages, LaTeX. The hep-th number added on the cover, and minor
typos correcte
Entropy function and attractors for AdS black holes
We apply Sen's entropy formalism to the study of the near horizon geometry
and the entropy of asymptotically AdS black holes in gauged supergravities. In
particular, we consider non-supersymmetric electrically charged black holes
with AdS_2 xS^{d-2} horizons in U(1)^4 and U(1)^3 gauged supergravities in d=4
and d=5 dimensions, respectively. We study several cases including
static/rotating, BPS and non-BPS black holes in Einstein as well as in
Gauss-Bonnet gravity. In all examples, the near horizon geometry and black hole
entropy are derived by extremizing the entropy function and are given entirely
in terms of the gauge coupling, the electric charges and the angular momentum
of the black hole.Comment: 27 pages, no figures, references adde
Thermal Pions at Finite Isospin Chemical Potential
The density corrections, in terms of the isospin chemical potential ,
to the mass of the pions are studied in the framework of the SU(2) low energy
effective chiral lagrangian. The pion decay constant is
also analized. As a function of temperature for , the mass remains
quite stable, starting to grow for very high values of , confirming previous
results. However, there are interesting corrections to the mass when both
effects (temperature and chemical potential) are simultaneously present. At
zero temperature the should condensate when . This is not longer valid anymore at finite . The mass of the
acquires also a non trivial dependence on due to the finite
temperature.Comment: 13 pages, 5 figure
Incidence and progression of hand osteoarthritis in a large community-based cohort: the Johnston County Osteoarthritis Project
Objective: To describe the incidence and progression of radiographic and symptomatic hand osteoarthritis (rHOA and sxHOA) in a large community-based cohort. Design: Data were from the Johnston County OA Project (1999–2015, 12 ± 1.2 years follow-up, age 45+). Participants had bilateral hand radiographs each visit, read for Kellgren–Lawrence grade (KLG) at 30 joints. We defined rHOA as KLG ≥2 in ≥1 joint. SxHOA was defined in a hand/joint with rHOA and self-reported symptoms or tenderness on exam. Incidence was assessed in those without, while progression was assessed in those with, baseline rHOA. Proportions or medians are reported; differences by sex and race were assessed using models appropriate for dichotomous or continuous definitions, additionally adjusted for age, education, body mass index (BMI), and weight change. Results: Of 800 participants (68% women, 32% African American, mean age 60 years), 327 had baseline rHOA and were older, more often white and female, than those without rHOA (n = 473). The incidence of HOA was high, for rHOA (60%) and for sxHOA (13%). Women were more likely than men to have incident HOA, particularly for distal interphalangeal joint radiographic osteoarthritis (DIP rOA) (adjusted odds ratios (aOR) 1.60 95% confidence intervals (95% CI) [1.03, 2.49]) and sxHOA (aOR 2.98 [1.50, 5.91]). Progressive HOA was more similar by sex, although thumb base rOA progressed more frequently in women than in men (aOR 2.56 [1.44, 4.55]). Particularly HOA incidence, but also progression, was more frequent among whites compared with African Americans. Conclusion: This study provides much needed information about the natural history of HOA, a common and frequently debilitating condition, in the general population
T violation and the unidirectionality of time
An increasing number of experiments at the Belle, BNL, CERN, DA{\Phi}NE and
SLAC accelerators are confirming the violation of time reversal invariance (T).
The violation signifies a fundamental asymmetry between the past and future and
calls for a major shift in the way we think about time. Here we show that
processes which violate T symmetry induce destructive interference between
different paths that the universe can take through time. The interference
eliminates all paths except for two that represent continuously forwards and
continuously backwards time evolution. Evidence from the accelerator
experiments indicates which path the universe is effectively following. This
work may provide fresh insight into the long-standing problem of modeling the
dynamics of T violation processes. It suggests that T violation has previously
unknown, large-scale physical effects and that these effects underlie the
origin of the unidirectionality of time. It may have implications for the
Wheeler-DeWitt equation of canonical quantum gravity. Finally it provides a
view of the quantum nature of time itself.Comment: 24 pages, 5 figures. Final version accepted for publishing in
Foundations of Physics. The final publication is available at
http://www.springerlink.com/content/y3h4174jw2w78322
Expedition 306 summary
The overall aim of the North Atlantic paleoceanography study of Integrated Ocean Drilling Program Expedition 306 is to place late Neogene–Quaternary climate proxies in the North Atlantic into a chronology based on a combination of geomagnetic paleointensity, stable isotope, and detrital layer stratigraphies, and in so doing generate integrated North Atlantic millennial-scale stratigraphies for the last few million years. To reach this aim, complete sedimentary sections were drilled by multiple advanced piston coring directly south of the central Atlantic “ice-rafted debris belt” and on the southern Gardar Drift. In addition to the North Atlantic paleoceanography study, a borehole observatory was successfully installed in a new ~180 m deep hole close to Ocean Drilling Program Site 642, consisting of a circulation obviation retrofit kit to seal the borehole from the overlying ocean, a thermistor string, and a data logger to document and monitor bottom water temperature variations through time
An Index for 4 dimensional Super Conformal Theories
We present a trace formula for an index over the spectrum of four dimensional
superconformal field theories on time. Our index receives
contributions from states invariant under at least one supercharge and captures
all information -- that may be obtained purely from group theory -- about
protected short representations in 4 dimensional superconformal field theories.
In the case of the theory our index is a function of four
continuous variables. We compute it at weak coupling using gauge theory and at
strong coupling by summing over the spectrum of free massless particles in
and find perfect agreement at large and small charges.
Our index does not reproduce the entropy of supersymmetric black holes in
, but this is not a contradiction, as it differs qualitatively from the
partition function over supersymmetric states of the theory. We
note that entropy for some small supersymmetric black holes may be
reproduced via a D-brane counting involving giant gravitons. For big black
holes we find a qualitative (but not exact) agreement with the naive counting
of BPS states in the free Yang Mills theory. In this paper we also evaluate and
study the partition function over the chiral ring in the Yang
Mills theory.Comment: harvmac 40+16 pages, v3: references and table of contents added,
typos fixe
Effects of comorbid cardiovascular disease and diabetes on hand osteoarthritis, pain, and functional state transitions: The Johnston county osteoarthritis project
Objective. The purpose of this study is to examine the course of hand osteoarthritis (HOA) and its relationship with cardiovascular disease (CVD) and diabetes (DM). Methods. Data were collected at 3 timepoints from 845 Johnston County Osteoarthritis Project participants (two-thirds women, one-third African Americans, mean age 60 yrs) with and without HOA, CVD, or DM. A diagnosis of radiographic HOA (rHOA) required a Kellgren-Lawrence severity grade of ≥ 2 in at least 3 joints in each hand. A 4-state progressive model included transitions based on rHOA and pain or function as defined using the Australian/Canadian HOA Index (AUSCAN). Markov multistate models estimated HR (aHR) and 95% CI for associations between DM or CVD and specific state transitions, adjusting for baseline and time-varying covariates. Results. Participants with DM (vs those without DM) were more likely to experience worsening pain with rHOA. Individuals who had or developed CVD (vs those who did not) were significantly less likely to experience symptomatic improvement, regardless of rHOA status. Those with DM or CVD (vs those without these comorbidities) were less likely to experience improvement in function, although this was statistically significant only for those with DM and no rHOA. Conclusion. Overall, having or developing DM and/or CVD reduced the likelihood of symptomatic and functional improvement over time, suggesting an effect of comorbid CVD and DM on the clinical and radiographic course of HOA. Additional studies are needed to confirm these findings
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