Conditions under which adjustability lowers the cost of a robust linear program

The adjustable robust counterpart (ARC) of an uncertain linear program extends the robust counterpart (RC) by allowing some decision variables to adjust to the realizations of some uncertain parameters. The ARC may product a less conservative solution than the RC does but cases are known in which it does not. While the literature documents some examples of cost savings provided by adjustability (particularly affine adjustability), it is not straightforward to determine in advance whether they will materialize. The affine adjustable robust counterpart, while having a tractable structure, still may be much larger than the original problem. We establish conditions under which affine adjustability may lover the optimal cost with a numerical condition that can be checked in small representative instances. As demonstrated in applications, the conditions provide insights into constraint relationships that allow adjustability to make a difference

Pilot based channel estimation improvement in orthogonal frequency-division multiplexing systems using linear predictive coding

Pilot based least square (LS) channel estimation is a commonly used channel estimation technique in orthogonal frequency-division multiplexing based systems due to its simplicity. However, LS estimation does not handle the noise effect and hence suffers from performance degradation. Since the channel coefficients are correlated in time and hence show a slower variation than the noise, it is possible to encode the channel using linear predictive coding (LPC) without the noise. In this work, the channel is estimated from the pilots using LS estimation and in a second step the channel’s LS estimated is encoded as LPC coefficients to produce an improved channel estimation. The estimation technique is simulated for space-time block coding (STBC) based orthogonal frequency-division multiplexing (OFDM) system and the bit error rate (BER) curves show improvement of the LPC estimation over the LS estimation of the channel

Continuous Uniform Finite Time Stabilization of Planar Controllable Systems

Continuous homogeneous controllers are utilized in a full state feedback setting for the uniform finite time stabilization of a perturbed double integrator in the presence of uniformly decaying piecewise continuous disturbances. Semiglobal strong $\mathcal{C}^1$ Lyapunov functions are identified to establish uniform asymptotic stability of the closed-loop planar system. Uniform finite time stability is then proved by extending the homogeneity principle of discontinuous systems to the continuous case with uniformly decaying piecewise continuous nonhomogeneous disturbances. A finite upper bound on the settling time is also computed. The results extend the existing literature on homogeneity and finite time stability by both presenting uniform finite time stabilization and dealing with a broader class of nonhomogeneous disturbances for planar controllable systems while also proposing a new class of homogeneous continuous controllers

Performance of STBC Based MIMO-OFDM Using Pilot-aided Channel Estimation

Many studies have been published to address the growing issues in wireless communication systems. Space-Time Block Coding (STBC) is an effective and practical MIMO-OFDM application that can address such issues. It is a powerful tool for increasing wireless performance by coding data symbols and transmitting diversity using several antennas. The most significant challenge is to recover the transmitted signal through a time-varying multipath fading channel and obtain a precise channel estimation to recover the transmitted information symbols. This work considers different pilot patterns for channel estimation and equalization in MIMO-OFDM systems. The pilot patterns fall under two general types: comb and block types, with a proper arrangement suitable to the multiple transmit antennas. The two main channel estimation methods, LS and MMSE, are compared by evaluating performance in terms of Bit Error Rate (BER) to analyze the performance of pilot-aided channel estimation for 2x2 and 4x4 MIMO arrangements utilizing LTE parameters and the effects of modifying different numbers of OFDM subcarriers under different channel models It has been discussed, a 4x4 system performs better than a 2x2 system in terms of BER with an acceptable amount of additional complexity

Complications neurologiques de la carence en thiamine (Vitamine B1) : A propos d’un cas avec revue de la litterature

Introduction: La carence en thiamine peut se manifester par deux formes cliniques : une forme cardiaque nommée béribéri humide, et une forme neurologique qui est le béribéri sec ; cette dernière peut se traduire cliniquement par une neuropathie périphérique, ou par une encéphalopathie de Gayet-Wernicke, caractérisée par la triade classique : ophtalmoplégie, ataxie et état confusionnel. Cette encéphalopathie est souvent difficile à identifier et son diagnostic est retardé. Observation: Nous rapportons le cas d’une patiente de 27 ans, suivie pour leucémie aigue promyélocytaire réfractaire, avec atteinte du système nerveux central, ayant eu une alimentation parentérale prolongée, en raison des vomissements incoercibles et persistants, suite à laquelle elle a développé une encéphalopathie de Wernicke, ayant bien évolué sous supplémentation vitaminique intra-veineuse. Commentaires:Nous aborderons dans ce travail, l’intérêt du diagnostic précoce, les différents contextes évocateurs et les aspects clinique, radiologique ainsi que les options thérapeutiques dans l’encéphalopathie de Wernicke.   English title: Neurological Complications Of Thiamine Deficiency, A Case Report With Literature Review Background: Thiamine deficiency can manifest itself in two clinical forms: a cardiac form called wet beriberi, and a neurological form which is dry beriberi; the latter can result clinically by peripheral neuropathy, or by Gayet-Wernicke encephalopathy, characterized by the classic triad: ophthalmoplegia, ataxia and confusional state. This encephalopathy is often difficult to identify and its diagnosis is delayed. Observation: We report the case of a 27-year-old patient, followed for refractory acute promyelocytic leukemia, with central nervous system damage, having had a prolonged parenteral diet, due to incoercible and persistent vomiting, following which she developed an encephalopathy of Wernicke, having evolved well under intravenous vitamin supplementation. Comments: In this work, we will discuss the interest of early diagnosis, the different suggestive contexts and the clinical, radiological aspects as well as the therapeutic options in Wernicke's encephalopathy

Assessing the Feasibility of a Mobile HIV Screening Unit in Vermont: A Community Survey

Introduction. Estimates show that 20% of HIV-positive individuals are unaware of their serostatus, in part due to limited access to testing services. Challenges of HIV testing within communities may be overcome by providing non-traditional avenues for testing and counseling, such as mobile HIV testing units. Such services have demonstrated success in increasing awareness of personal HIV status, and facilitating diagnosis and treatment.https://scholarworks.uvm.edu/comphp_gallery/1196/thumbnail.jp

Comparison between Transcriptome Sequencing and 16S Metagenomics for Detection of Bacterial Pathogens in Wildlife

Background Rodents are major reservoirs of pathogens responsible for numerous zoonotic diseases in humans and livestock. Assessing their microbial diversity at both the individual and population level is crucial for monitoring endemic infections and revealing microbial association patterns within reservoirs. Recently, NGS approaches have been employed to characterize microbial communities of different ecosystems. Yet, their relative efficacy has not been assessed. Here, we compared two NGS approaches, RNA-Sequencing (RNA-Seq) and 16S-metagenomics, assessing their ability to survey neglected zoonotic bacteria in rodent populations.Methodology/Principal Findings : We first extracted nucleic acids from the spleens of 190 voles collected in France. RNA extracts were pooled, randomly retro-transcribed, then RNA-Seq was performed using HiSeq. Assembled bacterial sequences were assigned to the closest taxon registered in GenBank. DNA extracts were analyzed via a 16S-metagenomics approach using two sequencers: the 454 GS-FLX and the MiSeq. The V4 region of the gene coding for 16S rRNA was amplified for each sample using barcoded universal primers. Amplicons were multiplexed and processed on the distinct sequencers. The resulting datasets were de-multiplexed, and each read was processed through a pipeline to be taxonomically classified using the Ribosomal Database Project. Altogether, 45 pathogenic bacterial genera were detected. The bacteria identified by RNA-Seq were comparable to those detected by 16S-metagenomics approach processed with MiSeq (16S-MiSeq). In contrast, 21 of these pathogens went unnoticed when the 16S-metagenomics approach was processed via 454-pyrosequencing (16S-454). In addition, the 16S-metagenomics approaches revealed a high level of coinfection in bank voles. Conclusions/Significance :We concluded that RNA-Seq and 16S-MiSeq are equally sensitive in detecting bacteria. Although only the 16S-MiSeq method enabled identification of bacteria in each individual reservoir, with subsequent derivation of bacterial prevalence in host populations, and generation of intra-reservoir patterns of bacterial interactions. Lastly, the number of bacterial reads obtained with the 16S-MiSeq could be a good proxy for bacterial prevalence

Interrogating intervention delivery and participants’ emotional states to improve engagement and implementation: A realist informed multiple case study evaluation of Engager

BACKGROUND: 'Engager' is an innovative 'through-the-gate' complex care intervention for male prison-leavers with common mental health problems. In parallel to the randomised-controlled trial of Engager (Trial registration number: ISRCTN11707331), a set of process evaluation analyses were undertaken. This paper reports on the depth multiple case study analysis part of the process evaluation, exploring how a sub-sample of prison-leavers engaged and responded to the intervention offer of one-to-one support during their re-integration into the community. METHODS: To understand intervention delivery and what response it elicited in individuals, we used a realist-informed qualitative multiple 'case' studies approach. We scrutinised how intervention component delivery lead to outcomes by examining underlying causal pathways or 'mechanisms' that promoted or hindered progress towards personal outcomes. 'Cases' (n = 24) were prison-leavers from the intervention arm of the trial. We collected practitioner activity logs and conducted semi-structured interviews with prison-leavers and Engager/other service practitioners. We mapped data for each case against the intervention logic model and then used Bhaskar's (2016) 'DREIC' analytic process to categorise cases according to extent of intervention delivery, outcomes evidenced, and contributing factors behind engagement or disengagement and progress achieved. RESULTS: There were variations in the dose and session focus of the intervention delivery, and how different participants responded. Participants sustaining long-term engagement and sustained change reached a state of 'crises but coping'. We found evidence that several components of the intervention were key to achieving this: trusting relationships, therapeutic work delivered well and over time; and an in-depth shared understanding of needs, concerns, and goals between the practitioner and participants. Those who disengaged were in one of the following states: 'Crises and chaos', 'Resigned acceptance', 'Honeymoon' or 'Wilful withdrawal'. CONCLUSIONS: We demonstrate that the 'implementability' of an intervention can be explained by examining the delivery of core intervention components in relation to the responses elicited in the participants. Core delivery mechanisms often had to be 'triggered' numerous times to produce sustained change. The improvements achieved, sustained, and valued by participants were not always reflected in the quantitative measures recorded in the RCT. The compatibility between the practitioner, participant and setting were continually at risk of being undermined by implementation failure as well as changing external circumstances and participants' own weaknesses. TRIAL REGISTRATION NUMBER: ISRCTN11707331, Wales Research Ethics Committee, Registered 02-04-2016-Retrospectively registered https://doi.org/10.1186/ISRCTN11707331