Memory effect in Dy0.5Sr0.5MnO3 single crystals

We have performed a series of magnetic aging experiments on single crystals of Dy0.5Sr0.5MnO3. The results demonstrate striking memory and chaos-like effects in this insulating half-doped perovskite manganite and suggest the existence of strong magnetic relaxation mechanisms of a clustered magnetic state. The spin-glass-like state established below a temperature T-sg approximate to 34 K originates from quenched disorder arising due to the ionic-radii mismatch at the rare earth site. However, deviations from the typical behavior seen in canonical spin glass materials are observed which indicate that the glassy magnetic properties are due to cooperative and frustrated dynamics in a heterogeneous or clustered magnetic state. In particular, the microscopic spin flip time obtained from dynamical scaling near the spin glass freezing temperature is four orders of magnitude larger than microscopic times found in atomic spin glasses. The magnetic viscosity deduced from the time dependence of the zero-field-cooled magnetization exhibits a peak at a temperature T < T-sg and displays a marked dependence on waiting time in zero field.

The Effects of Reduction Mammaplasty

Symptomatic hypertrophic breasts cause a health burden with physical and psychosocial morbidity. The value of reduction mammaplasty in the treatment of symptomatic breast hypertrophy has been consistently reported by patients and has been well recognised by plastic surgeons for a long time. However, the scientific evidence of the effects of reduction mammaplasty has been weak or lacking. During the design of this study most of the previous studies were retrospective and the few prospective studies had methodological limitations. Therefore, an obvious need for prospective randomised studies was present. Nevertheless, practical and ethical considerations seemed to make this study design impossible, because the waiting time for the operation was several years. The legislation and subsequent introduction of the uniform criteria for access to non-emergency treatment in Finland removed these obstacles, as all patients received their treatment within a reasonable time. As a result, a randomised controlled trial with a six-month follow-up time was designed and conducted. In addition, a follow-up study with two to five years follow-up was also carried out later. The effects of reduction mammaplasty on the patients breast-related symptoms, psychological symptoms, pain and quality of life was assessed. In addition, factors affecting the outcome were investigated. This study was carried out in the Hospital District of Helsinki and Uusimaa, Finland. Eighty-two out of the approximately 300 patients on the waiting list in 2004 agreed to participate in the study. Patients were randomised either to be operated (40 patients) on or to be followed up (42 patients). The follow-up time for both groups was six months. The patients were operated on by plastic surgeons or trainees at the Department of Plastic Surgery at Helsinki University Central Hospital or at the Department of Surgery at Hyvinkää Hospital. The patients completed five questionnaires: the SF-36 and the 15D quality of life questionnaires, the Finnish Breast-Associated Symptoms questionnaire (FBAS), a mood questionnaire (Raitasalo s modification of the short form of the Beck Depression Inventory, RBDI), and a pain questionnaire (The Finnish Pain Questionnaire, FPQ). Sixty-two out of the original 82 patients agreed to participate in the prospective follow-up study. In this study, patients completed the 15D quality of life questionnaire, the Finnish Breast-Associated Symptoms questionnaire, and the RBDI mood questionnaire. After six months follow-up, patients who had undergone reduction mammaplasty had a significantly better quality of life, fewer breast-associated symptoms and less pain, and they were less depressed or anxious when compared to patients who had not undergone surgery. The change in quality of life was more than two times the minimal clinically important difference. The patients preoperative quality of life was significantly inferior when compared to the age-standardised general population. This health burden was removed with reduction mammaplasty. The health loss related to symptomatic breast hypertrophy was comparable to that of patients with major joint arthrosis. In terms of change in quality of life, the intervention effect of reduction mammaplasty was comparable to that of hip joint replacement and more pronounced than that of knee joint replacement surgery. The outcome of reduction mammaplasty was affected more by preoperative psychosocial factors than by changes in breast dimensions. The effects of reduction mammaplasty remained stable at two to five years follow-up. In terms of quality of life, symptomatic breast hypertrophy causes a considerable health loss comparable to that of major joint arthrosis. Patients who undergo surgery have fewer breast-associated symptoms and less pain, and they are less depressed or anxious and have an improved quality of life. The intervention effect is comparable to that of major joint replacement surgery, and it remains stable at two to five years follow-up. The outcome of reduction mammaplasty is affected by preoperative psychosocial factors.

Performance analysis of the random early detection algorithm

In this article we consider a finite queue with its arrivals controlled by the random early detection algorithm. This is one of the most prominent congestion avoidance schemes in the Internet routers. The aggregate arrival stream from the population of transmission control protocol sources is locally considered stationary renewal or Markov modulated Poisson process with general packet length distribution. We study the exact dynamics of this queue and provide the stability and the rates of convergence to the stationary distribution and obtain the packet loss probability and the waiting time distribution. Then we extend these results to a two traffic class case with each arrival stream renewal. However, computing the performance indices for this system becomes computationally prohibitive. Thus, in the latter half of the article, we approximate the dynamics of the average queue length process asymptotically via an ordinary differential equation. We estimate the error term via a diffusion approximation. We use these results to obtain approximate transient and stationary performance of the system. Finally, we provide some computational examples to show the accuracy of these approximations.

Relaxation and jump dynamics of water at the mica interface

The orientational relaxation dynamics of water confined between mica surfaces is investigated using molecular dynamics simulations. The study illustrates the wide heterogeneity that exists in the dynamics of water adjacent to a strongly hydrophilic surface such as mica. Analysis of the survival probabilities in different layers is carried out by normalizing the corresponding relaxation times with bulk water layers of similar thickness. A 10-fold increase in the survival times is observed for water directly in contact with the mica surface and a non-monotonic variation in the survival times is observed moving away from the mica surface to the bulk-like interior. The orientational relaxation time is highest for water in the contact layer, decreasing monotonically away from the surface. In all cases the ratio of the relaxation times of the 1st and 2nd rank Legendre polynomials of the HH bond vector is found to lie between 1.5 and 1.9 indicating that the reorientational relaxation in the different water layers is governed by jump dynamics. The orientational dynamics of water in the contact layer is particularly novel and is found to undergo distinct two-dimensional hydrogen bond jump reorientational dynamics with an average waiting time of 4.97 ps. The waiting time distribution is found to possess a long tail extending beyond 15 ps. Unlike previously observed jump dynamics in bulk water and other surfaces, jump events in the mica contact layer occur between hydrogen bonds formed by the water molecule and acceptor oxygens on the mica surface. Despite slowing down of the water orientational relaxation near the surface, life-times of water in the hydration shell of the K ion are comparable to that observed in bulk salt solutions. (C) 2012 American Institute of Physics. http://dx.doi.org/10.1063/1.4717710]

How Do Glassy Domains Grow?

We construct equations for the growth kinetics of structural glass within mode-coupling theory, through a nonstationary variant of the three-density correlator defined by G. Biroli et al. Phys. Rev. Lett. 97, 195701 (2006)]. We solve a schematic form of the resulting equations to obtain the coarsening of the three-point correlator chi(3)(t, t(w)) as a function of waiting time tw. For a quench into the glass, we find that chi(3) attains a peak value similar to t(w)(0.5) at t - t(w) similar to t(w)(0.8), providing a theoretical basis for the numerical observations of Parisi J. Phys. Chem. B 103, 4128 (1999)] and Kob and Barrat Phys. Rev. Lett. 78, 4581 (1997)]. The aging is not ``simple'': the t(w) dependence cannot be attributed to an evolving effective temperature.

Packet scheduling for priority based transmission in energy harvesting sensors

In this paper, we determine packet scheduling policies for efficient power management in Energy Harvesting Sensors (EHS) which have to transmit packets of high and low priorities over a fading channel. We assume that incoming packets are stored in a buffer and the quality of service for a particular type of message is determined by the expected waiting time of packets of that type of message. The sensors are constrained to work with the energy that they garner from the environment. We derive transmit policies which minimize the sum of expected waiting times of the two types of messages, weighted by penalties. First, we show that for schemes with a constant rate of transmission, under a decoupling approximation, a form of truncated channel inversion is optimal. Using this result, we derive optimal solutions that minimize the weighted sum of the waiting times in the different queues.

Probabilistic Prediction based Scheduling for Delay Sensitive Traffic in Internet of Things

This paper proposes a probabilistic prediction based approach for providing Quality of Service (QoS) to delay sensitive traffic for Internet of Things (IoT). A joint packet scheduling and dynamic bandwidth allocation scheme is proposed to provide service differentiation and preferential treatment to delay sensitive traffic. The scheduler focuses on reducing the waiting time of high priority delay sensitive services in the queue and simultaneously keeping the waiting time of other services within tolerable limits. The scheme uses the difference in probability of average queue length of high priority packets at previous cycle and current cycle to determine the probability of average weight required in the current cycle. This offers optimized bandwidth allocation to all the services by avoiding distribution of excess resources for high priority services and yet guaranteeing the services for it. The performance of the algorithm is investigated using MPEG-4 traffic traces under different system loading. The results show the improved performance with respect to waiting time for scheduling high priority packets and simultaneously keeping tolerable limits for waiting time and packet loss for other services. Crown Copyright (C) 2015 Published by Elsevier B.V.

Influence of recombination on acquisition and reversion of immune escape and compensatory mutations in HIV-1

Following transmission, HIV-1 adapts in the new host by acquiring mutations that allow it to escape from the host immune response at multiple epitopes. It also reverts mutations associated with epitopes targeted in the transmitting host but not in the new host. Moreover, escape mutations are often associated with additional compensatory mutations that partially recover fitness costs. It is unclear whether recombination expedites this process of multi-locus adaptation. To elucidate the role of recombination, we constructed a detailed population dynamics model that integrates viral dynamics, host immune response at multiple epitopes through cytotoxic T lymphocytes, and viral evolution driven by mutation, recombination, and selection. Using this model, we compute the expected waiting time until the emergence of the strain that has gained escape and compensatory mutations against the new host's immune response, and reverted these mutations at epitopes no longer targeted. We find that depending on the underlying fitness landscape, shaped by both costs and benefits of mutations, adaptation proceeds via distinct dominant pathways with different effects of recombination, in particular distinguishing escape and reversion. When adaptation at a single epitope is involved, recombination can substantially accelerate immune escape but minimally affects reversion. When multiple epitopes are involved, recombination can accelerate or inhibit adaptation depending on the fitness landscape. Specifically, recombination tends to delay adaptation when a purely uphill fitness landscape is accessible at each epitope, and accelerate it when a fitness valley is associated with each epitope. Our study points to the importance of recombination in shaping the adaptation of HIV-1 following its transmission to new hosts, a process central to T cell-based vaccine strategies. (C) 2015 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license.

Uma casa, tempo de espera e silêncio: uma leitura de Ontem não te vi em Babilónia e O arquipélago da insónia, de António Lobo Antunes

Este trabalho se propõe a analisar duas obras do escritor português António Lobo Antunes, tendo em vista algumas instâncias narrativas, que, a nosso ver, sobressaem na obra do autor. As obras são Ontem não te vi em Babilónia, romance publicado em 2006, e O arquipélago da insónia, de 2008. Os dois romances compõem o ciclo de produção mais recente do autor, no qual as experimentações formais e estéticas são mais intensas do que nos romances anteriores. Além disso, as obras apresentam convergências temáticas já explicitadas por uma leitura atenta de seus títulos. Ontem não te vi é a representação de um tempo de espera, um tempo de frustração; Babilónia é Babel, símbolo maior da incomunicabilidade para o Ocidente. Já arquipélago é um conjunto de ilhas, reunião marcada pelo isolamento e pela incomunicabilidade; insónia é, igualmente, uma espera frustrada por algo que não vem, no caso, o sono, que nos romances será metáfora para a morte. O trabalho privilegiará, portanto, a análise do espaço, a partir do símbolo da casa; do tempo, insone e de morte; e do texto, que se apresenta, essencialmente, por uma enxurrada discursiva. Assim, pretende-se entrar no universo antuniano e, como parece ser o desejo do autor, desvendar a nós mesmos e a nosso tempo

A dinâmica da demanda por serviços de saúde no município de Piraí, RJ, do ponto de vista da medicalização

Apesar da definição da Estratégia de Saúde da Família (ESF) como porta de entrada preferencial do sistema de saúde e estratégia de reorganização da assistência, os usuários do SUS, vêm demonstrando historicamente preferência pelo serviço de urgência/emergência hospitalar. Neste contexto, o campo do presente estudo é a cidade de Piraí e seus habitantes, que desde 2002 contam com 100% de cobertura da ESF, modelo que dá ênfase: à lógica territorial na assistência, no cuidado continuado e transversal, no vínculo e no acesso facilitado pelo acolhimento humanizado e escuta qualificada; ocupando o centro da rede de serviços atuando como ordenador e coordenador do cuidado. Avaliando os dados de produtividade (com foco nas consultas médicas) hospitalar e da ESF notamos que a busca por assistência médica hospitalar, tem aumentado exponencialmente, e pode-se perceber que a grande maioria destes usuários se apresenta ao serviço com demandas de atenção básica, o que é considerado ilógico e contraditório na visão de gestores e profissionais. A prática profissional tem me levado a um processo de reflexão sobre as expectativas dos usuários ao procurarem o sistema de saúde (principalmente a ESF), sobre os caminhos que cada um deles constrói diante de uma questão de saúde e como se dá a tomada de decisão em busca da resolutividade da questão. Dessa forma, o objetivo deste trabalho é compreender como se constrói essa demanda; que critérios estão envolvidos na tomada de decisão desses usuários ao optarem pelo serviço de emergência como porta de entrada preferencial; mesmo em um município que oferece um serviço estruturado, pautado nas diretrizes da ESF e com uma cobertura que alcança toda a sua população. Acreditamos que o processo conhecido como medicalização da vida, que descreve o processo pelo qual problemas não médicos são definidos e tratados como problemas médicos, usualmente em termos de doenças e desordens (CONRAD, 2007); influencie na construção dessa demanda. Quanto a metodologia, foram realizadas entrevistas semiestruturadas, com usuários do SUS, residentes no município e que buscaram espontaneamente o serviço de urgência/emergência hospitalar. Verificou-se que a imagem que o usuário faz dos serviços de saúde se relaciona principalmente com o tempo de espera pelo atendimento, o acesso (interpretado principalmente como a certeza/incerteza do atendimento) e a acessibilidade. Os usuários frequentemente se referem à organização das unidades da ESF com o significado de barreiras ao acesso (principalmente pela necessidade de agendamento) e demonstram ter em relação às USF uma imagem de grande limitação de recursos humanos (quase exclusivamente em relação ao médico) e materiais. Por outro lado, prontos-socorros e hospitais se apresentam para eles, por várias razões, como espaços de acesso garantido. É importante ressaltar que o processo de medicalização da vida aparece como parte importante da engrenagem que move a construção dessa demanda.

Incorporação e remodelação de enxertos homólogos na reconstrução alveolar em humanos: análise tomográfica, histológica e histomorfométrica

Enxertos ósseos homólogos congelados têm sido documentados apresentando bons resultados clínicos como substituto ao material autógeno nas reconstruções alveolares. Entretanto, dados referentes à incorporação e remodelação destes enxertos não estão disponíveis na literatura. Este estudo tem por objetivo determinar um período ótimo de espera para instalação de implantes em rebordos reconstruídos com enxertos ósseos homólogos em bloco no que se refere à incorporação e reabsorção. 24 pacientes foram submetidos à reconstrução alveolar óssea homóloga previamente à instalação de implantes. Os indivíduos foram alocados randomicamente em um de 3 grupos de acordo com o tempo de espera para o segundo estágio cirúrgico (4, 6 e 8 meses). Análises tomográficas, histológicas e histomorfométricas foram utilizadas a fim de determinar o grau de reabsorção e incorporação dos enxertos nos diferentes intervalos de tempo para cada grupo. Os dados de reabsorção sofrida pelos enxertos demonstraram diferenças estatisticamente significativas para os três intervalos de espera. Da mesma forma, parâmetros histomorfométricos como contagem de osteócitos e quantificação de remanescentes de osso homólogo nas biópsias apresentaram diferenças significativas entre os grupos. De acordo com os dados do presente trabalho, no que diz respeito à remodelação e incorporação, o período mais favorável à instalação dos implantes a curto prazo após recontruções com enxertos homólogos é de 4 meses.

Voltammetric study of vitamin K-3 at interdigitated array microelectrodes

Cyclic voltammetry of Vitamin K-3 (V-K3) was measured with Pt disk electrode, platinum interdigitated array (Pt-IDA) and Au-IDA microelectrodes in single and dual modes. The effects of pH, scan rate and collector potential on the current of generator and collector were studied. The collection efficiency of V-K3 at IDA electrodes was measured. The linear ranges for current response as a function of V-K3 concentration were found to he 10 mu M-1 mM (i(g)) and 1 mu M - 1 mM (i(c)) for the generator and collector of the Pt-IDA electrode, respectively. The effects of waiting time, potential difference and pulse electrolysis time in differential pulse voltammetry (DPV) on the peak current of V-K3 were studied to get the optimal condition at 0.1 M Na2HPO4, pH 11.50 and 11.0 for Au-IDA and Pt-IDA, respectively.

基于PMAC开放式数控系统软件开发

基于PC和多轴运动控制器的开放式数控系统是理想的开放式数控系统。介绍了基于PMAC的开放式数控系统结构形式,PMAC的差补、位置控制、伺服功能、以PMAC和PC机为硬件平台搭建了数控系统,并对其硬件构成和软件设计结构进行了分析。着重从软件设计的角度,介绍了PTALK控件的功能和作用,对数控系统软件构成进行了详细的阐述。并设计出了友好的用户界面,在实际应用中具有重要意义。

慢性海洛因成瘾者的冲动性和行为抑制缺陷脑机制

In recent years, the deficit of inhibition has become an important reason for explaining addiction. Response inhibition resembles the compulsive drug seeking behavior and it is the basement of addiction inhibition deficits. However, there were no enough evidence for the relationship between addiction and response inhibition deficits and the results of the neuro mechanisms studies remains unclear. Few studies has focused on the exploring the heroin users. Among those paradigms for study response inhibition deficits, stop signal is a very suitable model for the representation of compulsive drug seeking, but only a few researches has worked on this paradigm. In this study, we selected about 100 heroin abusers and had behaviour and neuro imaging scannings for investigating the response inhibition deficits. The behaviour researches found: first, the chronic heroin users had longer reaction time than control group and this reaction time were not affected by stop signals in heroin users. Second, heroin users had less waiting time than control group and they were more impulsive but less flexibility. Their erro monitoring and flexibale adjustment ability decreased. Third, the SSRT of heroin users was significantly longer than control group. These results suggested that the inhibition of heroin users were impaired. Further investigation showed that the SSRT of heroin users had positive correlation of four factor scores of ASI and the macro correlation coefficient was factor three of drug use. This correlation suggested that drug use was the main reason of inhibition deficits. fMRI results mainly focused on the ANOVA analysis for group difference. First, there was no intensity difference in M1 and SMA brain areas between the two groups. Second, heroin users had less activation in right dorsalateral prefrontal cortex, right inferior prefrontal cortex and anterior cingulated cortex, while in bilateral striatum and amygdala, heroin users had more activation than control group. The right prefrontal cortex was indentified as the main inhibition brain area. The anterior cingulated cortex has relationship with erro monitoring and amygdale was an important brain area for impulsivity and emotion control. The network of these brain areas was envovled in impulsivity and inhibition and it was suggested the mainly damaged network for heroin users’ disinhibition. We also investigated the gray matter changes of heroin users and found that chonic heroin use made their gray matter density decreased in prefrontal cortex (including bilateral dorsalateral prefrontal cortex, obital frontal cortex, inferior prefrontal cortex) and anterior cingulated cortex. The gray matter density in these brain regions had negative correlation with drug use duration. In conclusion, we indentified the disinhibition of heroin users and its neuro mechanism. Their compulsivity brain areas had more activation than control group and their inhibition brain areas had less activation than normal control. On the other side, the biological mechanism of this activation changes was the gray matter density decrease in these brain areas.

To Queue or Not to Queue: When Queueing is Better Than Timesharing in a Distributed System

We examine the question of whether to employ the first-come-first-served (FCFS) discipline or the processor-sharing (PS) discipline at the hosts in a distributed server system. We are interested in the case in which service times are drawn from a heavy-tailed distribution, and so have very high variability. Traditional wisdom when task sizes are highly variable would prefer the PS discipline, because it allows small tasks to avoid being delayed behind large tasks in a queue. However, we show that system performance can actually be significantly better under FCFS queueing, if each task is assigned to a host based on the task's size. By task assignment, we mean an algorithm that inspects incoming tasks and assigns them to hosts for service. The particular task assignment policy we propose is called SITA-E: Size Interval Task Assignment with Equal Load. Surprisingly, under SITA-E, FCFS queueing typically outperforms the PS discipline by a factor of about two, as measured by mean waiting time and mean slowdown (waiting time of task divided by its service time). We compare the FCFS/SITA-E policy to the processor-sharing case analytically; in addition we compare it to a number of other policies in simulation. We show that the benefits of SITA-E are present even in small-scale distributed systems (four or more hosts). Furthermore, SITA-E is a static policy that does not incorporate feedback knowledge of the state of the hosts, which allows for a simple and scalable implementation.