5,873 research outputs found
Measurement of , K, p transverse momentum spectra with ALICE in proton-proton collisions at 0.9 and 7 TeV
Results of the measurement of the , K, p transverse momentum
() spectra at mid-rapidity in proton-proton collisions at
TeV are presented. Particle identification was performed using
the energy loss signal in the Inner Tracking System (ITS) and the Time
Projection Chamber (TPC), while information from the Time-of-Flight (TOF)
detector was used to identify particles at higher transverse momentum. From the
spectra at TeV the mean transverse momentum ()
and particle ratios were extracted and compared to results obtained for
collisions at TeV and lower energies.Comment: Quark Matter 2011 proceeding
Differentiation of Cardiac from Noncardiac Pleural Effusions in Cats using Second-Generation Quantitative and Point-of-Care NT-proBNP Measurements
BACKGROUND: Pleural effusion is a common cause of dyspnea in cats. Nâterminal proâBâtype natriuretic peptide (NTâproBNP) measurement, using a firstâgeneration quantitative ELISA, in plasma and pleural fluid differentiates cardiac from noncardiac causes of pleural effusion. HYPOTHESIS/OBJECTIVES: To determine whether NTâproBNP measurements using secondâgeneration quantitative ELISA and pointâofâcare (POC) tests in plasma and pleural fluid distinguish cardiac from noncardiac pleural effusions and how results compare to the firstâgeneration ELISA. ANIMALS: Thirtyâeight cats (US cohort) and 40 cats (UK cohort) presenting with cardiogenic or noncardiogenic pleural effusion. METHODS: Prospective cohort study. Twentyâone and 17 cats in the US cohort, and 22 and 18 cats in the UK cohort were classified as having cardiac or noncardiac pleural effusion, respectively. NTâproBNP concentrations in paired plasma and pleural fluid samples were measured using secondâgeneration ELISA and POC assays. RESULTS: The secondâgeneration ELISA differentiated cardiac from noncardiac pleural effusion with good diagnostic accuracy (plasma: sensitivity, 95.2%, specificity, 82.4%; pleural fluid: sensitivity, 100%, specificity, 76.5%). NTâproBNP concentrations were greater in pleural fluid (719 pmol/L (134â1500)) than plasma (678 pmol/L (61â1500), P = 0.003), resulting in different cutâoff values depending on the sample type. The POC test had good sensitivity (95.2%) and specificity (87.5%) when using plasma samples. In pleural fluid samples, the POC test had good sensitivity (100%) but low specificity (64.7%). Diagnostic accuracy was similar between firstâ and secondâgeneration ELISA assays. CONCLUSIONS AND CLINICAL IMPORTANCE: Measurement of NTâproBNP using a quantitative ELISA in plasma and pleural fluid or POC test in plasma, but not pleural fluid, distinguishes cardiac from noncardiac causes of pleural effusion in cats
Electrochromic orbit control for smart-dust devices
Recent advances in MEMS (micro electromechanical systems) technology are leading to spacecraft which are the shape and size of computer chips, so-called SpaceChips, or âsmart dust devicesâ. These devices can offer highly distributed sensing when used in future swarm applications. However, they currently lack a feasible strategy for active orbit control. This paper proposes an orbit control methodology for future SpaceChip devices which is based on exploiting the effects of solar radiation pressure using electrochromic coatings. The concept presented makes use of the high area-to-mass ratio of these devices, and consequently the large force exerted upon them by solar radiation pressure, to control their orbit evolution by altering their surface optical properties. The orbital evolution of Space Chips due to solar radiation pressure can be represented by a Hamiltonian system, allowing an analytic development of the control methodology. The motion in the orbital element phase space resembles that of a linear oscillator, which is used to formulate a switching control law. Additional perturbations and the effect of eclipses are accounted for by modifying the linearized equations of the secular change in orbital elements around an equilibrium point in the phase space of the problem. Finally, the effectiveness of the method is demonstrated in a test case scenario
Slow relaxation to equipartition in spring-chain systems
In this study, one-dimensional systems of masses connected by springs, i.e.,
spring-chain systems, are investigated numerically. The average kinetic energy
of chain-end particles of these systems is larger than that of other particles,
which is similar to the behavior observed for systems made of masses connected
by rigid links. The energetic motion of the end particles is, however,
transient, and the system relaxes to thermal equilibrium after a while, where
the average kinetic energy of each particle is the same, that is, equipartition
of energy is achieved. This is in contrast to the case of systems made of
masses connected by rigid links, where the energetic motion of the end
particles is observed in equilibrium. The timescale of relaxation estimated by
simulation increases rapidly with increasing spring constant. The timescale is
also estimated using the Boltzmann-Jeans theory and is found to be in quite
good agreement with that obtained by the simulation
Efficacy of pimobendan in the prevention of congestive heart failure or sudden death in doberman pinschers with preclinical dilated cardiomyopathy (the PROTECT study)
<p>Background: The benefit of pimobendan in delaying the progression of preclinical dilated cardiomyopathy (DCM) in Dobermans is not reported.</p>
<p>Hypothesis: That chronic oral administration of pimobendan to Dobermans with preclinical DCM will delay the onset of CHF or sudden death and improve survival.</p>
<p>Animals: Seventy-six client-owned Dobermans recruited at 10 centers in the UK and North America.</p>
<p>Methods: The trial was a randomized, blinded, placebo-controlled, parallel group multicenter study. Dogs were allocated in a 1:1 ratio to receive pimobendan (Vetmedin capsules) or visually identical placebo.</p>
<p>The composite primary endpoint was prospectively defined as either onset of CHF or sudden death. Time to death from all causes was a secondary endpoint.</p>
<p>Results: The proportion of dogs reaching the primary endpoint was not significantly different between groups (PÂ =Â .1). The median time to the primary endpoint (onset of CHF or sudden death) was significantly longer in the pimobendan (718Â days, IQR 441â1152Â days) versus the placebo group (441Â days, IQR 151â641Â days) (log-rank PÂ =Â 0.0088). The median survival time was significantly longer in the pimobendan (623Â days, IQR 491â1531Â days) versus the placebo group (466Â days, IQR 236â710Â days) (log-rank PÂ =Â .034).</p>
<p>Conclusion and Clinical Importance: The administration of pimobendan to Dobermans with preclinical DCM prolongs the time to the onset of clinical signs and extends survival. Treatment of dogs in the preclinical phase of this common cardiovascular disorder with pimobendan can lead to improved outcome.</p>
Habitat fragmentation and genetic variability of tetrapod populations
In the last two centuries, the development of human civilization has transformed large natural areas into anthropogenic landscapes, making habitat fragmentation a pervasive feature of modern landscapes. In animal populations, habitat fragmentation may alter their genetic diversity and structure due to limited gene flow and dispersion and reduced effective population sizes, potentially leading to genetic drift in small habitat patches. We tested the hypothesis that habitat fragmentation affects genetic diversity of tetrapod populations through a meta-analysis. We also examined certain life history traits of species and particular external landscape factors that may determine the magnitude of genetic erosion observed in fragmented habitats. Our results showed that habitat fragmentation reduces overall genetic diversity of tetrapod populations. Stronger negative fragmentation effects were detected for amphibians, birds, and mammals. Within each taxonomic group, species with large body size were more strongly affected by fragmentation. Particularly within mammals, we found that less vagile species with short generation times represent the most susceptible tetrapod group to lose genetic diversity in fragmented habitats. As external drivers, we found a non-significant trend of lower fragmentation effects in study systems of less than 50 years and stronger effects in older (>100 years) fragmented systems. As expected, the extent of habitat loss was also important in determining the magnitude of genetic erosion in tetrapods. Extreme habitat loss showed stronger negative effects on genetic diversity irrespectively of taxonomic groups. The information gathered in this review also highlights research bias and gaps in the literature.Fil: Rivera OrtĂz, F. A.. Universidad Nacional Autonoma de Mexico. Centro de Investigaciones En Ecosistemas; MĂ©xicoFil: Aguilar, Ramiro. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico CĂłrdoba. Instituto Multidisciplinario de BiologĂa Vegetal (p); ArgentinaFil: Arizmendi, M. D. C.. Universidad Nacional AutĂłnoma de MĂ©xico; MĂ©xicoFil: Quesada, M.. Universidad Nacional Autonoma de Mexico. Centro de Investigaciones En Ecosistemas; MĂ©xicoFil: Oyama, K.. Universidad Nacional Autonoma de Mexico. Centro de Investigaciones En Ecosistemas; MĂ©xic
Coalescence in the 1D Cahn-Hilliard model
We present an approximate analytical solution of the Cahn-Hilliard equation
describing the coalescence during a first order phase transition. We have
identified all the intermediate profiles, stationary solutions of the noiseless
Cahn-Hilliard equation. Using properties of the soliton lattices, periodic
solutions of the Ginzburg-Landau equation, we have construct a family of ansatz
describing continuously the processus of destabilization and period doubling
predicted in Langer's self similar scenario
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