272 research outputs found
Resveratrol Improves Survival, Hemodynamics and Energetics in a Rat Model of Hypertension Leading to Heart Failure
Heart failure (HF) is characterized by contractile dysfunction associated with altered energy metabolism. This study was aimed at determining whether resveratrol, a polyphenol known to activate energy metabolism, could be beneficial as a metabolic therapy of HF. Survival, ventricular and vascular function as well as cardiac and skeletal muscle energy metabolism were assessed in a hypertensive model of HF, the Dahl salt-sensitive rat fed with a high-salt diet (HS-NT). Resveratrol (18 mg/kg/day; HS-RSV) was given for 8 weeks after hypertension and cardiac hypertrophy were established (which occurred 3 weeks after salt addition). Resveratrol treatment improved survival (64% in HS-RSV versus 15% in HS-NT, p<0.001), and prevented the 25% reduction in body weight in HS-NT (P<0.001). Moreover, RSV counteracted the development of cardiac dysfunction (fractional shortening â34% in HS-NT) as evaluated by echocardiography, which occurred without regression of hypertension or hypertrophy. Moreover, aortic endothelial dysfunction present in HS-NT was prevented in resveratrol-treated rats. Resveratrol treatment tended to preserve mitochondrial mass and biogenesis and completely protected mitochondrial fatty acid oxidation and PPARα (peroxisome proliferator-activated receptor α) expression. We conclude that resveratrol treatment exerts beneficial protective effects on survival, endotheliumâdependent smooth muscle relaxation and cardiac contractile and mitochondrial function, suggesting that resveratrol or metabolic activators could be a relevant therapy in hypertension-induced HF
Evidence of Validity and Factorial Invariance of a Brief Jealousy Scale in Peruvian University Students
The study sought to analyze the evidences of validity, factorial invariance and reliability of the scores of the Jealousy Subscale of the Inventory of Emotional Communication in Romantic Relationships (Sanchez, 2012). To that effect, there was a sample of 1176 Peruvian university students who completed the 11 items of the original version. The confirmatory factor analysis verified a satisfactory adjustment of a final model of nine items in a single factor and correlated errors. It is concluded that the Jealousy scale is a measure that can be used in the professional and research activity, obtaining valid interpretations, reliable and invariant scores according to gender in Peruvian university students.El estudio buscĂł analizar las evidencias de validez, invarianza factorial y fiabilidad de las puntuaciones de la Subescala de Celos del Inventario de ComunicaciĂłn Emocional en las Relaciones RomĂĄnticas (SĂĄnchez, 2012). Para ello se contĂł con una muestra de 1176 estudiantes universitarios peruanos que completaron los 11 Ătems de la versiĂłn original. El anĂĄlisis factorial confirmatorio verificĂł un ajuste satisfactorio de un modelo final de nueve Ătems en un Ășnico factor y errores correlacionados. Se concluye que la escala de Celos constituye una medida breve que puede emplearse en la actividad profesional e investigativa, obteniendo interpretaciones vĂĄlidas, puntuaciones fiables e invariantes de acuerdo con el sexo en estudiantes universitarios peruanos
Psychometric evidence of a brief measure of resilience in non-institutionalized Peruvian older adults
Resilience is understood as the domain of personal resources and contextual factors that allow for a successful coping and enhance positive adaptation to the different stressors during the lifespan, thereby being important for a healthy and successful aging. Nowadays, several brief instruments have been developed to measure resilience, such as the Brief Resilient Coping Scale (BRCS), an instrument that measures the ability of people to confront stress in an adaptive way. In this vein, the study provides evidence of the validity and reliability of the BRCS in non-institutionalized older adults in Peru. Two hundred thirty-six elderly people of both genders, 78.4% women and 21.6% men, with a mean age of 72.8 years (SD= 6.90), who answered the Spanish version of the BRCS and other scales to measure satisfaction with life, humor as coping, and depression. Confirmatory factor analysis corroborates the one-dimensional structure of the BRCS. The coefficients of internal consistency, Chronbach's alpha and omega, indicated an adequate reliability of the BRCS. Both the adjustment indices of the model and the values of the coefficients of reliability were higher compared to those reported in the literature. The BRCS showed positive and significant correlations with satisfaction with life and humor as coping (p < .01). Likewise, negative and significant correlations were observed with depression (p < .01). The results show that the BRCS has proved valid and reliable, supporting its use as a short measure of resilience in older Peruvians.La resiliencia es comprendida como el dominio de recursos personales y factores contextuales que permiten un
afrontamiento exitoso y el logro de una adaptaciĂłn positiva ante los diferentes estresores que aparecen a lo largo de la
vida, siendo asĂ importante dentro del proceso de envejecimiento saludable y exitoso. En la actualidad se han desarrollado
instrumentos breves para la mediciĂłn de la resiliencia como la escala breve de resiliencia (BRCS - Brief Resilient Coping
Scale) que evalĂșa la capacidad de los individuos para hacer frente al estrĂ©s de manera adaptativa. En este sentido, el
estudio ofrece evidencia de validez y fiabilidad de la BRCS en adultos mayores no institucionalizados peruanos. Se contĂł
con la participación de 236 adultos mayores con una edad promedio de 72.8 años (DT = 6.90) de los cuales el 78.4%
eran mujeres y el 21.6% hombres, quienes respondieron la versión en español del BRCS y otras escalas para medir la
satisfacciĂłn con la vida, humor como afrontamiento y depresiĂłn. Mediante el anĂĄlisis factorial confirmatorio se corrobora
la estructura unidimensional de la BRCS. Los coeficientes de consistencia interna alfa de Cronbach y omega indicaron una
adecuada fiabilidad de la BRCS. Tanto los Ăndices de ajuste del modelo como los valores de los coeficientes de fiabilidad
fueron mejores en comparaciĂłn con los reportados en la literatura. La BRCS mostrĂł una correlaciĂłn positiva significativa
con la satisfacciĂłn con la vida y el humor como afrontamiento (p < .01). Asimismo, se observĂł una correlaciĂłn negativa
significativa con depresiĂłn (p < .01). Los resultados muestran que la BRCS cuenta con evidencias de validez y fiabilidad que
avala su empleo como medida breve de la resiliencia en adultos mayores peruanos
Galactic Gamma-Ray Diffuse Emission at TeV energies with HAWC Data
The Galactic gamma-ray diffuse emission (GDE) is emitted by cosmic rays
(CRs), ultra-relativistic protons and electrons, interacting with gas and
electromagnetic radiation fields in the interstellar medium. Here we present
the analysis of TeV diffuse emission from a region of the Galactic Plane over
the range in longitude of , using data collected with
the High Altitude Water Cherenkov (HAWC) detector. Spectral, longitudinal and
latitudinal distributions of the TeV diffuse emission are shown. The radiation
spectrum is compatible with the spectrum of the emission arising from a CR
population with an "index" similar to that of the observed CRs. When comparing
with the \texttt{DRAGON} \textit{base model}, the HAWC GDE flux is higher by
about a factor of two. Unresolved sources such as pulsar wind nebulae and TeV
halos could explain the excess emission. Finally, deviations of the Galactic CR
flux from the locally measured CR flux may additionally explain the difference
between the predicted and measured diffuse fluxes
The Long-Baseline Neutrino Experiment: Exploring Fundamental Symmetries of the Universe
The preponderance of matter over antimatter in the early Universe, the
dynamics of the supernova bursts that produced the heavy elements necessary for
life and whether protons eventually decay --- these mysteries at the forefront
of particle physics and astrophysics are key to understanding the early
evolution of our Universe, its current state and its eventual fate. The
Long-Baseline Neutrino Experiment (LBNE) represents an extensively developed
plan for a world-class experiment dedicated to addressing these questions. LBNE
is conceived around three central components: (1) a new, high-intensity
neutrino source generated from a megawatt-class proton accelerator at Fermi
National Accelerator Laboratory, (2) a near neutrino detector just downstream
of the source, and (3) a massive liquid argon time-projection chamber deployed
as a far detector deep underground at the Sanford Underground Research
Facility. This facility, located at the site of the former Homestake Mine in
Lead, South Dakota, is approximately 1,300 km from the neutrino source at
Fermilab -- a distance (baseline) that delivers optimal sensitivity to neutrino
charge-parity symmetry violation and mass ordering effects. This ambitious yet
cost-effective design incorporates scalability and flexibility and can
accommodate a variety of upgrades and contributions. With its exceptional
combination of experimental configuration, technical capabilities, and
potential for transformative discoveries, LBNE promises to be a vital facility
for the field of particle physics worldwide, providing physicists from around
the globe with opportunities to collaborate in a twenty to thirty year program
of exciting science. In this document we provide a comprehensive overview of
LBNE's scientific objectives, its place in the landscape of neutrino physics
worldwide, the technologies it will incorporate and the capabilities it will
possess.Comment: Major update of previous version. This is the reference document for
LBNE science program and current status. Chapters 1, 3, and 9 provide a
comprehensive overview of LBNE's scientific objectives, its place in the
landscape of neutrino physics worldwide, the technologies it will incorporate
and the capabilities it will possess. 288 pages, 116 figure
Should I Stay or Should I Go: Stellar Wind Retention and Expulsion in Massive Star Clusters
Mass and energy injection throughout the lifetime of a star cluster
contributes to the gas reservoir available for subsequent episodes of star
formation and the feedback energy budget responsible for ejecting material from
the cluster. In addition, mass processed in stellar interiors and ejected as
winds has the potential to augment the abundance ratios of currently forming
stars, or stars which form at a later time from a retained gas reservoir. Here
we present hydrodynamical simulations that explore a wide range of cluster
masses, compactnesses, metallicities and stellar population age combinations in
order to determine the range of parameter space conducive to stellar wind
retention or wind powered gas expulsion in star clusters. We discuss the
effects of the stellar wind prescription on retention and expulsion
effectiveness, using MESA stellar evolutionary models as a test bed for
exploring how the amounts of wind retention/expulsion depend upon the amount of
mixing between the winds from stars of different masses and ages. We conclude
by summarizing some implications for gas retention and expulsion in a variety
of compact () star clusters including
young massive star clusters (, ~Myrs), intermediate age clusters (, ~Gyrs), and globular clusters (, ~Gyrs).Comment: 18 pages, 14 figures, version resubmitted to MNRAS after minor
referee comment
Simulation of Postsynaptic Glutamate Receptors Reveals Critical Features of Glutamatergic Transmission
Activation of several subtypes of glutamate receptors contributes to changes in postsynaptic calcium concentration at hippocampal synapses, resulting in various types of changes in synaptic strength. Thus, while activation of NMDA receptors has been shown to be critical for long-term potentiation (LTP) and long term depression (LTD) of synaptic transmission, activation of metabotropic glutamate receptors (mGluRs) has been linked to either LTP or LTD. While it is generally admitted that dynamic changes in postsynaptic calcium concentration represent the critical elements to determine the direction and amplitude of the changes in synaptic strength, it has been difficult to quantitatively estimate the relative contribution of the different types of glutamate receptors to these changes under different experimental conditions. Here we present a detailed model of a postsynaptic glutamatergic synapse that incorporates ionotropic and mGluR type I receptors, and we use this model to determine the role of the different receptors to the dynamics of postsynaptic calcium with different patterns of presynaptic activation. Our modeling framework includes glutamate vesicular release and diffusion in the cleft and a glutamate transporter that modulates extracellular glutamate concentration. Our results indicate that the contribution of mGluRs to changes in postsynaptic calcium concentration is minimal under basal stimulation conditions and becomes apparent only at high frequency of stimulation. Furthermore, the location of mGluRs in the postsynaptic membrane is also a critical factor, as activation of distant receptors contributes significantly less to calcium dynamics than more centrally located ones. These results confirm the important role of glutamate transporters and of the localization of mGluRs in postsynaptic sites in their signaling properties, and further strengthen the notion that mGluR activation significantly contributes to postsynaptic calcium dynamics only following high-frequency stimulation. They also provide a new tool to analyze the interactions between metabotropic and ionotropic glutamate receptors
Sensitivity of the Cherenkov Telescope Array to TeV photon emission from the Large Magellanic Cloud
A deep survey of the Large Magellanic Cloud at âŒ0.1-100 TeV photon energies with the Cherenkov Telescope Array is planned. We assess the detection prospects based on a model for the emission of the galaxy, comprising the four known TeV emitters, mock populations of sources, and interstellar emission on galactic scales. We also assess the detectability of 30 Doradus and SN 1987A, and the constraints that can be derived on the nature of dark matter. The survey will allow for fine spectral studies of N 157B, N 132D, LMC P3, and 30 Doradus C, and half a dozen other sources should be revealed, mainly pulsar-powered objects. The remnant from SN 1987A could be detected if it produces cosmic-ray nuclei with a flat power-law spectrum at high energies, or with a steeper index 2.3-2.4 pending a flux increase by a factor of >3-4 over âŒ2015-2035. Large-scale interstellar emission remains mostly out of reach of the survey if its >10 GeV spectrum has a soft photon index âŒ2.7, but degree-scale 0.1-10 TeV pion-decay emission could be detected if the cosmic-ray spectrum hardens above >100 GeV. The 30 Doradus star-forming region is detectable if acceleration efficiency is on the order of 1â10 per cent of the mechanical luminosity and diffusion is suppressed by two orders of magnitude within <100 pc. Finally, the survey could probe the canonical velocity-averaged cross-section for self-annihilation of weakly interacting massive particles for cuspy Navarro-Frenk-White profiles
HE-LHC: The High-Energy Large Hadron Collider â Future Circular Collider Conceptual Design Report Volume 4
In response to the 2013 Update of the European Strategy for Particle Physics (EPPSU), the Future Circular Collider (FCC) study was launched as a world-wide international collaboration hosted by CERN. The FCC study covered an energy-frontier hadron collider (FCC-hh), a highest-luminosity high-energy lepton collider (FCC-ee), the corresponding 100 km tunnel infrastructure, as well as the physics opportunities of these two colliders, and a high-energy LHC, based on FCC-hh technology. This document constitutes the third volume of the FCC Conceptual Design Report, devoted to the hadron collider FCC-hh. It summarizes the FCC-hh physics discovery opportunities, presents the FCC-hh accelerator design, performance reach, and staged operation plan, discusses the underlying technologies, the civil engineering and technical infrastructure, and also sketches a possible implementation. Combining ingredients from the Large Hadron Collider (LHC), the high-luminosity LHC upgrade and adding novel technologies and approaches, the FCC-hh design aims at significantly extending the energy frontier to 100 TeV. Its unprecedented centre-of-mass collision energy will make the FCC-hh a unique instrument to explore physics beyond the Standard Model, offering great direct sensitivity to new physics and discoveries
- âŠ