10,046 research outputs found
Parameter constraints for high-energy models of colliding winds of massive stars: the case WR 147
We explore the ability of high energy observations to constrain orbital
parameters of long period massive binary systems by means of an inverse Compton
model acting in colliding wind environments. This is particular relevant for
(very) long period binaries where orbital parameters are often poorly known
from conventional methods, as is the case e.g. for the Wolf-Rayet (WR) star
binary system WR 147 where INTEGRAL and MAGIC upper limits on the high-energy
emission have recently been presented. We conduct a parameter study of the set
of free quantities describing the yet vaguely constrained geometry and
respective effects on the non-thermal high-energy radiation from WR 147. The
results are confronted with the recently obtained high-energy observations and
with sensitivities of contemporaneous high-energy instruments like Fermi-LAT.
For binaries with sufficient long periods, like WR 147, gamma-ray attenuation
is unlikely to cause any distinctive features in the high-energy spectrum. This
leaves the anisotropic inverse Compton scattering as the only process that
reacts sensitively on the line-of-sight angle with respect to the orbital
plane, and therefore allows the deduction of system parameters even from
observations not covering a substantial part of the orbit.
Provided that particle acceleration acts sufficiently effectively to allow
the production of GeV photons through inverse Compton scattering, our analysis
indicates a preference for WR 147 to possess a large inclination angle.
Otherwise, for low inclination angles, electron acceleration is constrained to
be less efficient as anticipated here.Comment: 33 pages, 9 figures; accepted by Ap
Ergodic Transport Theory, periodic maximizing probabilities and the twist condition
The present paper is a follow up of another one by A. O. Lopes, E. Oliveira
and P. Thieullen which analyze ergodic transport problems. Our main focus will
a more precise analysis of case where the maximizing probability is unique and
is also a periodic orbit.
Consider the shift T acting on the Bernoulli space \Sigma={1, 2, 3,..,
d}^\mathbb{N} A:\Sigma \to \mathbb{R} a Holder potential.
Denote m(A)=max_{\nu is an invariant probability for T} \int A(x) \; d\nu(x)
and, \mu_{\infty,A}, any probability which attains the maximum value. We assume
this probability is unique (a generic property). We denote \T the bilateral
shift. For a given potential Holder A:\Sigma \to \mathbb{R}, we say that a
Holder continuous function W: \hat{\Sigma} \to \mathbb{R} is a involution
kernel for A, if there is a Holder function A^*:\Sigma \to \mathbb{R}, such
that, A^*(w)= A\circ \T^{-1}(w,x)+ W \circ \T^{-1}(w,x) - W(w,x). We say that
A^* is a dual potential of A. It is true that m(A)=m(A^*). We denote by V the
calibrated subaction for A, and, V^* the one for A^*. We denote by I^* the
deviation function for the family of Gibbs states for \beta A, when \beta \to
\infty.
For each x we get one (more than one) w_x such attains the supremum above.
That is, solutions of V(x) = W(w_x,x) - V^* (w_x)- I^*(w_x).
A pair of the form (x,w_x) is called an optimal pair. If \T is the shift
acting on (x,w) \in {1, 2, 3,.., d}^\mathbb{Z}, then, the image by \T^{-1} of
an optimal pair is also an optimal pair.
Theorem - Generically, in the set of Holder potentials A that satisfy
(i) the twist condition,
(ii) uniqueness of maximizing probability which is supported in a periodic
orbit, the set of possible optimal w_x, when x covers the all range of possible
elements x in \in \Sigma, is finite
Origins, potency, and heterogeneity of skeletal muscle fibro-adipogenic progenitors—time for new definitions
Striated muscle is a highly plastic and regenerative organ that regulates body movement, temperature, and metabolism—all the functions needed for an individual’s health and well-being. The muscle connective tissue’s main components are the extracellular matrix and its resident stromal cells, which continuously reshape it in embryonic development, homeostasis, and regeneration. Fibro-adipogenic progenitors are enigmatic and transformative muscle-resident interstitial cells with mesenchymal stem/stromal cell properties. They act as cellular sentinels and physiological hubs for adult muscle homeostasis and regeneration by shaping the microenvironment by secreting a complex cocktail of extracellular matrix components, diffusible cytokines, ligands, and immune-modulatory factors. Fibro-adipogenic progenitors are the lineage precursors of specialized cells, including activated fibroblasts, adipocytes, and osteogenic cells after injury. Here, we discuss current research gaps, potential druggable developments, and outstanding questions about fibro-adipogenic progenitor origins, potency, and heterogeneity. Finally, we took advantage of recent advances in single-cell technologies combined with lineage tracing to unify the diversity of stromal fibro-adipogenic progenitors. Thus, this compelling review provides new cellular and molecular insights in comprehending the origins, definitions, markers, fate, and plasticity of murine and human fibro-adipogenic progenitors in muscle development, homeostasis, regeneration, and repair
Adherent muscle connective tissue fibroblasts are phenotypically and biochemically equivalent to stromal fibro/adipogenic progenitors
Extracellular matrix (ECM) gives structure, support, and is the niche for several cells found in skeletal muscle. ECM is mainly produced by muscle connective tissue (CT) fibroblasts during development and regeneration. Stromal fibroadipogenic progenitors (FAPs) are CT fibroblasts-like mesenchymal progenitors (MPs) with important roles in regeneration and degeneration. Chronic damage restrains the normal regenerative behavior of muscle fibroblasts/FAPs. Thus, the isolation and study of these mesenchymal progenitors are of crucial importance for understanding their behavior and biology. We investigated whether adult muscle CT fibroblasts (hereafter referred to as adherent fibroblasts [aFbs]) cultured via pre-plating strategy belong to a heterogeneous population of FAPs. By combining microscopy, western blot analyses, flow cytometry, and FACS we determined that aFbs isolated from skeletal muscle largely overlap with FAPs. In addition, we used the PDGFRαEGFP mice in order to corroborate our results with EGFP+ FAPs. Moreover, our strategy allows the isolation of activated EGFP+ FAPs from the murine DMD model PDGFRαEGFP; mdx and PDGFRαEGFP denervated mice. Here we report that 1 h 30 min of pre-plating strategy allows the isolation and culture of a highly enriched population of aFbs. These cells are phenotypically and biochemically a FAPs-like population of adherent cells. In addition, aFbs respond in the same fashion as FAPs to Nilotinib, an inducer of FAPs apoptosis. Moreover, flow cytometry characterization of these aFbs suggests that 85% of them express the MP marker PDGFRα, and isolation of aFbs from the PDGFRαEGFP mice suggests that 75% of them show high EGFP expression. Furthermore, TGF-β1 induces aFbs proliferation, myofibroblast differentiation, and ECM production. We were also able to isolate activated aFbs from skeletal muscle of the DMD mice and from the PDGFRαEGFP mice 2-days after denervation. Our findings suggest that the in vitro pre-plating strategy allows the isolation and culture of a relatively pure aFbs population, which resembles FAPs in vitro
Torsion induces Gravity
In this work the Poincare-Chern Simons and Anti de Sitter Chern Simons
gravities are studied. For both a solution that can be casted as a black hole
with manifest torsion is found. Those solutions resemble Schwarzschild and
Schwarzschild-AdS solutions respectively.Comment: 4 pages, RevTe
The recess school space and time as an opportunity healthy
El propósito de nuestro estudio piloto fue medir de forma objetiva la AF saludable de la población infantil a lo largo de una semana e identificar cuanta de la misma se realizaba dentro del tiempo dedicado al recreo escolar. La muestra estaba compuesta por 36 niños de 11 a 12 años de una escuela de la provincia de Toledo en España. El instrumento utilizado fue el acelerómetro. La mayoría de los niños y niñas no cumplían las recomendaciones de AF saludable. En relación a la cantidad de AF saludable realizada en los recreos durante la semana, ésta presentó un peso importanteThe purpose of our pilot study was to measure objectively the amount of moderate to vigorous PA (MVPA) children engaged over a week and to identify how much of it was carried out during recess time. The sample comprised 36 children aged 11 to 12 from a school in the province of Toledo in Spain. PA was measured with the accelerometer GT1M. Most of the children did not meet the PA recommendations for health. In relation to the amount of MVPA achieved during recess time, our study suggests that recess time represents an important load of the total amount of children’s MVPA registered per da
Supersymmetric partners of the trigonometric Poschl-Teller potentials
The first and second-order supersymmetry transformations are used to generate
Hamiltonians with known spectra departing from the trigonometric Poschl-Teller
potentials. The several possibilities of manipulating the initial spectrum are
fully explored, and it is shown how to modify one or two levels, or even to
leave the spectrum unaffected. The behavior of the new potentials at the
boundaries of the domain is studied.Comment: 20 pages, 4 figure
Pulsar Prospects for the Cherenkov Telescope Array
In the last few years, the Fermi-LAT telescope has discovered over a 100
pulsars at energies above 100 MeV, increasing the number of known gamma-ray
pulsars by an order of magnitude. In parallel, imaging Cherenkov telescopes,
such as MAGIC and VERITAS, have detected for the first time VHE pulsed
gamma-rays from the Crab pulsar. Such detections have revealed that the Crab
VHE spectrum follows a power-law up to at least 400 GeV, challenging most
theoretical models, and opening wide possibilities of detecting more pulsars
from the ground with the future Cherenkov Telescope Array (CTA). In this
contribution, we study the capabilities of CTA for detecting Fermi pulsars. For
this, we extrapolate their spectra with "Crab-like" power-law tails in the VHE
range, as suggested by the latest MAGIC and VERITAS results.Comment: 4 pages, 3 figures. In Proceedings of the 2012 Heidelberg Symposium
on High Energy Gamma-Ray Astronomy. All CTA contributions at arXiv:1211.184
Anthropological utopia of the new kingdom of San Francisco: Fray Marcos de Niza and the american dream
La topografía y cartografía del septentrión novohispano sedujeron a exploradores,
navegantes y evangelizadores dispuestos a hallar su bagaje y propensiones en un terreno
desconocido, en el actual norte de México. Fray Marcos de Niza sobresale de entre sus coetáneos, ya
que su expedición recoge mitos y leyendas de ciudades maravillosas sobre las que la administración
virreinal requería certificaciones y juramentos. La experiencia del franciscano en ambos polos
continentales y, sobre todo, su formación religiosa de raigambre medieval sustentan un viaje que
vislumbró, paradójicamente, las ultimidades de la historia en el Nuevo Mundo. Su “Relación”,
muchas veces leída como un falso testimonio, guarda entre líneas un correlato místico cifrado en
el Apocalipsis. Fray Marcos entrevió un Nuevo Reino de San Francisco poblado por tribus que
parecían coincidir con las profecías de san Juan. Esta voluntad reduccionista devino en una utopía
propicia para la diplomacia entre naciones y la conversión al catolicismo. El sueño americano del
misionero debe enmarcarse bajo la ilusión de una metrópoli que vaticinaba la parusía de Cristo en
la antesala de un nuevo milenio.The Northern Novohispanic topography and cartography seduced explorers, sailors and
missionaries willing to find their background and inclinations over an unknown land that nowadays is the north of Mexico. Fray Marcos de Niza stands out among his contemporaries due to his
expedition, which gathers myths and legends from marvelous cities that the Viceregal administration
required certifications and oaths. The Franciscan vast experience in both continental poles and
especially his medieval religious roots, sustained a journey that paradoxically took a glimpse of
the last period of the History of the New World. His Relation, though many times taken as a false
testimony, preserves scattered between lines a mystical correlate encoded in the Apocalypse. Fray
Marcos distinguished a New Kingdom of San Francisco inhabited by tribes that seemed to concur
with Saint John’s prophecies. This reductionist willingness resulted in a utopia that was suitable
for the diplomacy between nations and the conversion to Catholicism. The missionary’s American
dream must be demarcated under the illusion of a metropolis that predicted the Parousia of Christ
just before the arrival of a new millennium
Habilidad de cuidado de los profesionales de enfermería de una institución prestadora de servicios de salud
Objetive: To measure the caring ability of nursing professionals that work in a third level Health Care Providing Institution in Sincelejo, Colombia. Methodology: This being a descriptive cross-sectional quantitative study, the sample consisted of 30 nurses from the care area, which were administered the Care Ability Inventory, which measures three categories: knowledge, value and patience. The information was processed through the Statistical Package for the Social Sciences: SPSS software. Results: The caregivers characterization reported that the age was between 20 to 30 years in the 53,3%, females predominated in 80,0% of the participants, the marital status, married, occupied 60,0%, work experience history surpassed 60 months 67,0% and 93,0% declared not suffering any chronic illnesses. In the caring ability aspect, 46,6% were placed in the medium category, 40,0% in the low and 13,3% in the high. Conclusions: The results show the need to strengthen the capacity of professional caregivers to face the everyday situations in the act of caring, in the aspects of knowledge, value and patience.Objetivo: Medir la habilidad de cuidado de los profesionales de enfermería que laboran en una Institución Prestadora de Servicios de Salud de tercer nivel de la ciudad de Sincelejo, Colombia, en el 2009. Metodología: Estudio descriptivo, cuantitativo de corte transversal: la muestra estuvo conformada por 30 enfermeros del área asistencial, a quienes se les aplicó el Inventario de Habilidad de Cuidado, que mide tres categorías: conocimiento, valor y paciencia. La información se procesó a través del programa Statistical Package for the Social Sciences (SPSS). Resultados: En la caracterización de los cuidadores se reportó que la edad estuvo comprendida entre 20 a 30 años en el 53,3%, el sexo femenino predominó en el 80,0% de los participantes, el estado civil casado ocupó un 60,0%,el tiempo de experiencia laboral superó los 60 meses en el 67,0% y el 93,0% expresó no padecer enfermedades crónicas. En cuanto a la habilidad de cuidado, el 46,6% se ubicó en la categoría media, el 40,0% en la baja y el 13,3% en la alta. Conclusiones: Los resultados muestran la necesidad de fortalecer en los cuidadores profesionales las capacidades de afrontamiento ante situaciones cotidianas del acto de cuidar, en las dimensiones conocimiento, valor y pacienci
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