Exact Nonequilibrium Work Generating Function for a Small Classical System

We obtain the exact nonequilibrium work generating function (NEWGF), for a small system consisting of a massive Brownian particle connected to internal and external springs. The external work is provided to the system for a finite time interval. The Jarzynski equality (JE), obtained in this case directly from the NEWGF, is shown to be valid for the present model, in an exact way regardless of the rate of external work

Structural and optical properties of europium doped zirconia single crystals fibers grown by laser floating zone

Yttria stabilized zirconia single crystal fibers doped with europium ions were developed envisaging optical applications. The laser floating zone technique was used in order to grow millimetric high quality single crystal fibers. The as-grown fibers are completely transparent and inclusion free, exhibiting a cubic structure. Under ultraviolet (UV) excitation, a broad emission band appears at 551 nm. The europium doped fibers are translucent with a tetragonal structure and exhibit an intense red emission at room temperature under UV excitation. The fingerprint transition lines between the 5D0 and 7FJ(0–4) multiplets of the Eu3+ ions are observed with the main emission line at ∼ 606 nm due to 5D0→7F2 transition. Photoluminescence excitation and wavelength dependent the photoluminescence spectra confirm the existence of different Eu3+ optical centers. © 2011 American Institute of PhysicsFCT-PTDC/CTM/66195/2006FCT-SFRH/BD/45774/200

Late Stillbirth: a Ten Year Cohort Study

Introduction: Late fetal death is a desolating event that inspite the effort to implement new surveillance protocols in perinatal continues to defy our clinical pratice. Objective: To examine etiological factors contributing to main causes and conditions associated with fetal death in late pregnancies over a 10-year period. Methods: Retrospective cohort analysis of 208 late singleton stillbirth delived in a tertiary-perinatal referral maternity over a 10-year period. Clinical charts, laboratory data and feto-placental pathology findings were systematically reviewed. Results: The incidence of late fetal demise was 3.5 per 1000 pregnancies. No significant trend in the incidence of stillbirth was demonstrated during the study period. Stillbirth was intrapartum in 12 (5.8%) cases and 72 (35%) were term pregnancies. Fourteen percent of cases were undersurveilled pregnancies. Mean gestacional age at diagnosis was 34 weeks. The primary cause of death was fetal, it was present in 59 cases, 25% were considered small for gestational age. Stillbirths were unexplained in 24.5% of cases. Maternal medical disorders were identified in 21%. Hypertensive disorders were frequent and associated with early gestacional age (p = 0.028). Conclusion: There was no change in the incidence of late stillbirth during the 10 years under evaluation. The incidence was 3.5 ‰ which was identical to that described in developed countries. About one quarter of the stillbirths was unexplained. The most frequent maternal pathology was chronic hypertension

Environmental and acoustic assessment: The AOB concept

The requirement for rapid environmental assessment has motivated the development of prediction tools, which allow the observation and prediction in very short notice, of the ocean evolution in an interval up to 3-4 weeks, in given littoral areas. Complex systems exist nowadays, where multidimensional quantities like the oceanographic-biogeochemical-optical-acoustic fields, are tracked in time, melding measures and models of some or all the involved quantities. At some point in the prediction system, the acoustic forecast is computed by acoustic propagation models taking as input the environmental forecast. Inevitably, the error of the acoustic forecast as given by the model output, originates from at least two error sources. The first is the environmental forecast error. The second is due to the model inaccuracies, and to the dependence of propagation on parameters not dealt with by the prediction system, like geometric or geo-acoustic properties. The acoustic community has developed a large number of acoustic inversion systems - based on e.g. matched-field processors or travel-time tomography - from which one can learn that an accurate acoustic simulation requires feeding the acoustic model with an environment which differs from the actual environment by a certain gap. This requires that the environmental forecast as given by ocean prediction systems be gap-compensated, prior to its inclusion in the acoustic environmental input. This paper puts the environmental gap in evidence, considering environmental forecasts, and historical and inverted data, to define heterogeneous environmental inputs to the propagation model. The corresponding acoustic outputs are compared to actual data from the MREA '03 sea trial. It is observed that acoustic inversion can play a significant role in converting the environmental forecast into the acoustic forecast. (c) 2007 Elsevier B.V. All rights reserved

Water column tomographic inversion with a network of drifting buoys

The estimation of ocean environmental properties by means of the inversion of acoustic signals has in several occasions been performed using a single vertical array of acoustic receivers, with a towed acoustic source as an attempt to ensure a rapid spatial coverage of the area of interest, as only a single ocean transect is "seen" at each time. Ideally, one would like to obtain an instantaneous picture of the complete area (volume) under observation. However, the resulting acoustic observations, hence environmental estimates, are not simultaneous in time. Using multiple acoustic receiving arrays appears to be a natural step towards both increasing the spatial coverage, and obtaining simultaneous environmental estimates of different ocean transects. It also gives a higher chance to capture spatial transient features, as for example solitons. Using multiple receiver arrays represents the addition of a new spatial dimension at the receiving end and opens up the number of possibilities to a Nx2D or full 3D view of the ocean. Taking support on the data set of the RADAR'07 experiment (July 9 - 16, 2007) where data was simultaneously collected on three vertical arrays, this paper explores space coherent processing of the several receiving arrays and Nx2D or 3D environmental constrained water coloumn matched-field inversion.FCT, Portugal under programs POCI, POSI and POCTI

Influence of the external pressure on the quantum correlations of molecular magnets

The study of quantum correlations in solid state systems is a large avenue for research and their detection and manipulation are an actual challenge to overcome. In this context, we show by using first-principles calculations on the prototype material KNaCuSi$_{4}$O$_{10}$ that the degree of quantum correlations in this spin cluster system can be managed by external hydrostatic pressure. Our results open the doors for research in detection and manipulation of quantum correlations in magnetic systems with promising applications in quantum information science

Finite size analysis of a two-dimensional Ising model within a nonextensive approach

In this work we present a thorough analysis of the phase transitions that occur in a ferromagnetic 2D Ising model, with only nearest-neighbors interactions, in the framework of the Tsallis nonextensive statistics. We performed Monte Carlo simulations on square lattices with linear sizes L ranging from 32 up to 512. The statistical weight of the Metropolis algorithm was changed according to the nonextensive statistics. Discontinuities in the m(T) curve are observed for $q\leq 0.5$. However, we have verified only one peak on the energy histograms at the critical temperatures, indicating the occurrence of continuous phase transitions. For the $0.5<q\leq 1.0$ regime, we have found continuous phase transitions between the ordered and the disordered phases, and determined the critical exponents via finite-size scaling. We verified that the critical exponents $\alpha$, $\beta$ and $\gamma$ depend on the entropic index $q$ in the range $0.5<q\leq 1.0$ in the form $\alpha (q)=(10 q^{2}-33 q+23)/20$, $\beta (q)=(2 q-1)/8$ and $\gamma (q)=(q^{2}-q+7)/4$. On the other hand, the critical exponent $\nu$ does not depend on $q$. This suggests a violation of the scaling relations $2 \beta +\gamma =d \nu$ and $\alpha +2 \beta +\gamma =2$ and a nonuniversality of the critical exponents along the ferro-paramagnetic frontier.Comment: accepted for publication in Phys. Rev.

Groove Pancreatitis with Biliary and Duodenal Stricture: An Unusual Cause of Obstructive Jaundice

INTRODUCTION: Groove pancreatitis is an uncommon cause of chronic pancreatitis that affects the groove anatomical area between the head of the pancreas, duodenum, and common bile duct. CLINICAL CASE: A 67-year-old man with frequent biliary colic and an alcohol consumption of 30-40 g/day was admitted to the hospital complaining of jaundice and pruritus. Laboratory analysis revealed cholestasis and the ultrasound scan showed intra-hepatic biliary ducts dilatation, middle third cystic dilatation of common bile duct, enlarged Wirsung and pancreatic atrophy. The magnetic resonance cholangiopancreatography showed imaging findings compatible with groove pancreatitis. An esophagogastroduodenoscopy later excluded duodenal neoplasia. He was submitted to a Roux-en-Y cholangiojejunostomy because of common bile duct stricture. Five months later a gastrojejunostomy was performed due to a duodenal stricture. The patient remains asymptomatic during follow-up. DISCUSSION: Groove pancreatitis is a benign cause of obstructive jaundice, whose main differential diagnosis is duodenal or pancreatic neoplasia. When this condition causes duodenal or biliary stricture, surgical treatment can be necessary.info:eu-repo/semantics/publishedVersio