95 resultados para background traffic


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Adult zebrafish Danio rerio originating from one stock used as control animals in a toxicological study were examined histopathologically for the occurrence of spontaneous lesions in the gonads. While no histopathological changes were seen in the testes, the ovaries showed lesions consisting mainly of acute granulomatous inflammation with increased atresia and the presence of egg debris in the ovarian parenchyma and in the oviduct. Since infectious agents could not be detected and the fish were not exposed to toxicants, we consider these lesions as spontaneous alterations of the ovaries.

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STUDY DESIGN Technical note and case series. OBJECTIVE To introduce an innovative minimal-invasive surgical procedure reducing surgery time and blood loss in management of U-shaped sacrum fractures. SUMMARY OF BACKGROUND Despite their seldom appearance, U-shaped fractures can cause severe neurological deficits and surgical management difficulties. According to the nature of the injury normally occurring in multi-injured patients after a fall from height, a jump, or road traffic accident, U-shaped fractures create a spinopelvic dissociation and hence are highly unstable. In the past, time-consuming open procedures like large posterior constructs or shortening osteotomies with or without decompression were the method of choice, sacrificing spinal mobility. Insufficient restoration of sacrococcygeal angle and pelvic incidence with conventional techniques may have adverse long-term effects in these patients. METHODS In a consecutive series of 3 patients, percutaneous reduction of the fracture with Schanz pins inserted in either the pedicles of L5 or the S1 body and the posterior superior iliac crest was achieved. The Schanz pins act as lever, allowing a good manipulation of the fracture. The reduction is secured by a temporary external fixator to permit optimal restoration of pelvic incidence and sacral kyphosis. Insertion of 2 transsacral screws allow fixation of the restored spinopelvic alignment. RESULTS Anatomic alignment of the sacrum was possible in each case. Surgery time ranged from 90 to 155 minutes and the blood loss was <50 mL in all 3 cases. Two patients had very good results in the long term regarding maintenance of pelvic incidence and sacrococcygeal angle. One patient with previous cauda equina decompression had loss of correction after 6 months. CONCLUSIONS Percutaneous reduction and transsacral screw fixation offers a less invasive method for treating U-shaped fractures. This can be advantageous in treatment of patients with multiple injuries.

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The paper presents a link layer stack for wireless sensor networks, which consists of the Burst-aware Energy-efficient Adaptive Medium access control (BEAM) and the Hop-to-Hop Reliability (H2HR) protocol. BEAM can operate with short beacons to announce data transmissions or include data within the beacons. Duty cycles can be adapted by a traffic prediction mechanism indicating pending packets destined for a node and by estimating its wake-up times. H2HR takes advantage of information provided by BEAM such as neighbour information and transmission information to perform per-hop congestion control. We justify the design decisions by measurements in a real-world wireless sensor network testbed and compare the performance with other link layer protocols.

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This paper is a summary of the main contribu- tions of the PhD thesis published in [1]. The main research contributions of the thesis are driven by the research question how to design simple, yet efficient and robust run-time adaptive resource allocation schemes within the commu- nication stack of Wireless Sensor Network (WSN) nodes. The thesis addresses several problem domains with con- tributions on different layers of the WSN communication stack. The main contributions can be summarized as follows: First, a a novel run-time adaptive MAC protocol is intro- duced, which stepwise allocates the power-hungry radio interface in an on-demand manner when the encountered traffic load requires it. Second, the thesis outlines a metho- dology for robust, reliable and accurate software-based energy-estimation, which is calculated at network run- time on the sensor node itself. Third, the thesis evaluates several Forward Error Correction (FEC) strategies to adap- tively allocate the correctional power of Error Correcting Codes (ECCs) to cope with timely and spatially variable bit error rates. Fourth, in the context of TCP-based communi- cations in WSNs, the thesis evaluates distributed caching and local retransmission strategies to overcome the perfor- mance degrading effects of packet corruption and trans- mission failures when transmitting data over multiple hops. The performance of all developed protocols are eval- uated on a self-developed real-world WSN testbed and achieve superior performance over selected existing ap- proaches, especially where traffic load and channel condi- tions are suspect to rapid variations over time.

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In this paper, we show statistical analyses of several types of traffic sources in a 3G network, namely voice, video and data sources. For each traffic source type, measurements were collected in order to, on the one hand, gain better understanding of the statistical characteristics of the sources and, on the other hand, enable forecasting traffic behaviour in the network. The latter can be used to estimate service times and quality of service parameters. The probability density function, mean, variance, mean square deviation, skewness and kurtosis of the interarrival times are estimated by Wolfram Mathematica and Crystal Ball statistical tools. Based on evaluation of packet interarrival times, we show how the gamma distribution can be used in network simulations and in evaluation of available capacity in opportunistic systems. As a result, from our analyses, shape and scale parameters of gamma distribution are generated. Data can be applied also in dynamic network configuration in order to avoid potential network congestions or overflows. Copyright © 2013 John Wiley & Sons, Ltd.

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BACKGROUND: Ethyl glucuronide (EtG) and ethyl sulfate (EtS) are non-oxidative minor metabolites of ethanol. They are detectable in various body fluids shortly after initial consumption of ethanol and have a longer detection time frame than the parent compound. They are regarded highly sensitive and specific markers of recent alcohol uptake. This study evaluates the determination of EtG and EtS from dried blood spots (DBS), a simple and cost-effective sampling method that would shorten the time gap between offense and blood sampling and lead to a better reflectance of the actual impairment. METHODS: For method validation, EtG and EtS standard and quality control samples were prepared in fresh human heparinized blood and spotted on DBS cards, then extracted and measured by an LC-ESI-MS/MS method. Additionally, 76 heparinized blood samples from traffic offense cases were analyzed for EtG and EtS as whole blood and as DBS specimens. The results from these measurements were then compared by calculating the respective mean values, by a matched-paired t test, by a Wilcoxon test, and by Bland-Altman and Mountain plots. RESULTS AND DISCUSSION: Calibrations for EtG and EtS in DBS were linear over the studied calibration range. The precision and accuracy of the method met the requirements of the validation guidelines that were employed in the study. The stability of the biomarkers stored as DBS was demonstrated under different storage conditions. The t test showed no significant difference between whole blood and DBS in the determination of EtG and EtS. In addition, the Bland-Altman analysis and Mountain plot confirmed that the concentration differences that were measured in DBS specimens were not relevant.

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Background Persons infected with human immunodeficiency virus (HIV) have increased rates of coronary artery disease (CAD). The relative contribution of genetic background, HIV-related factors, antiretroviral medications, and traditional risk factors to CAD has not been fully evaluated in the setting of HIV infection. Methods In the general population, 23 common single-nucleotide polymorphisms (SNPs) were shown to be associated with CAD through genome-wide association analysis. Using the Metabochip, we genotyped 1875 HIV-positive, white individuals enrolled in 24 HIV observational studies, including 571 participants with a first CAD event during the 9-year study period and 1304 controls matched on sex and cohort. Results A genetic risk score built from 23 CAD-associated SNPs contributed significantly to CAD (P = 2.9×10−4). In the final multivariable model, participants with an unfavorable genetic background (top genetic score quartile) had a CAD odds ratio (OR) of 1.47 (95% confidence interval [CI], 1.05–2.04). This effect was similar to hypertension (OR = 1.36; 95% CI, 1.06–1.73), hypercholesterolemia (OR = 1.51; 95% CI, 1.16–1.96), diabetes (OR = 1.66; 95% CI, 1.10–2.49), ≥1 year lopinavir exposure (OR = 1.36; 95% CI, 1.06–1.73), and current abacavir treatment (OR = 1.56; 95% CI, 1.17–2.07). The effect of the genetic risk score was additive to the effect of nongenetic CAD risk factors, and did not change after adjustment for family history of CAD. Conclusions In the setting of HIV infection, the effect of an unfavorable genetic background was similar to traditional CAD risk factors and certain adverse antiretroviral exposures. Genetic testing may provide prognostic information complementary to family history of CAD.

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Attention deficit/hyperactivity disorder (ADHD) is an increasingly recognized comorbid condition in subjects with substance use disorders (SUDs). This paper describes the methods and study population of the International ADHD in Substance Use Disorders Prevalence (IASP) study. Objectives of the IASP are to determine the prevalence of ADHD in adult treatment seeking patients with SUD in different countries and SUD populations, determine the reliability and validity of the Adult ADHD Self-report Scale V 1.1 (ASRS) as ADHD screening instrument in SUD populations, investigate the comorbidity profile of SUD patients with and without ADHD, compare risk factors and protective factors in SUD patients with and without a comorbid diagnosis of ADHD, and increase our knowledge about the relationship between ADHD and the onset and course of SUD. In this cross-sectional, multi-centre two stage study, subjects were screened for ADHD with the ASRS, diagnosed with the Conner's Adult ADHD Diagnostic Interview for DSM-IV (CAADID), and evaluated for SUD, major depression, bipolar disorder, anti social personality disorder and borderline personality disorder. Three thousand five hundred and fifty-eight subjects from 10 countries were included. Of these 40.9% screened positive for ADHD. This is the largest international study on this population evaluating ADHD and comorbid disorders.

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This article looks at the negotiations between Switzerland and Germany on air traffic regulation with the help of negotiation analysis tools. A number of factors pre-eminent in the literature on negotiation processes and outcomes are presented and critically assessed. In particular arguments of “power”, which are often insufficiently explored in analysing interstate cooperation, are brought back into the picture. The article argues that structural power best explains the negotiation results while domestic politics and information asymmetries both account for non-ratification of the treaty. Institutionalist arguments on the constraining effects of international norms and institutions as well as explanations focusing on negotiation skills are of minor importance. Moreover, the nature of the Swiss intra-governmental setting at the federal level did not encourage the Swiss negotiators to exploit all means during the different stages of the bargaining process. The article concludes by illuminating a number of policy observations in the broader context of Swiss foreign relations and indicating avenues for further research