Supervised learning for kinetic consensus control

In this paper, how to successfully and efficiently condition a target population of agents towards consensus is discussed. To overcome the curse of dimensionality, the mean field formulation of the consensus control problem is considered. Although such formulation is designed to be independent of the number of agents, it is feasible to solve only for moderate intrinsic dimensions of the agents space. For this reason, the solution is approached by means of a Boltzmann procedure, i.e. quasi-invariant limit of controlled binary interactions as approximation of the mean field PDE. The need for an efficient solver for the binary interaction control problem motivates the use of a supervised learning approach to encode a binary feedback map to be sampled at a very high rate. A gradient augmented feedforward neural network for the Value function of the binary control problem is considered and compared with direct approximation of the feedback law

Gradient-augmented supervised learning of optimal feedback laws using state-dependent Riccati equations

A supervised learning approach for the solution of large-scale nonlinear stabilization problems is presented. A stabilizing feedback law is trained from a dataset generated from State-dependent Riccati Equation solvers. The training phase is enriched by the use of gradient information in the loss function, which is weighted through the use of hyperparameters. High-dimensional nonlinear stabilization tests demonstrate that real-time sequential large-scale Algebraic Riccati Equation solvers can be substituted by a suitably trained feedforward neural network

Estágio profissional de intervenção em fisioterapia neurológica com pacientes adultos após aciente vascular cerebral

Mestrado em Fisioterapia NeurológicaIntrodução: A Fisioterapia Neurológica é uma área de intervenção essencial na medida em que existem cada vez mais doentes com sequelas resultantes de lesões do sistema nervoso central a necessitar de cuidados de fisioterapia, nomeadamente doentes com Acidente Vascular Cerebral já que as taxas de incidência são altas e a mortalidade tem vindo a decrescer com os avanços da medicina. Por outro lado, os conhecimentos atuais da área da neurociência permitem que a intervenção do fisioterapeuta seja baseada na evidência. Objetivos: Aprofundar conhecimentos, capacidades e competências em Fisioterapia Neurológica em pacientes adultos; intervindo essencialmente, em pacientes com sequelas de Acidente Vascular Cerebral, desenvolvendo o modelo de raciocínio clínico e investigando a efetividade do conceito de Bobath na funcionalidade de pacientes pós Acidente Vascular Cerebral. Metodologia: O estágio articulou a vertente de investigação, a dimensão pedagógica e a prática clínica; decorreu no Hospital Curry Cabral (Centro Hospitalar Lisboa Central) com pacientes adultos a realizar fisioterapia, em regime de internamento ou ambulatório, devido a patologia neurológica e mais especificamente com pacientes com sequelas de AVC; teve a duração de 200h. Foram selecionadas três escalas de funcionalidade (o Indicador de Barthel Modificado, a Medida de Independência Funcional e a Motor Assessement Scale) para a avaliação dos casos clínicos acompanhados e a abordagem em fisioterapia foi baseada no Conceito de Bobath. Resultados: Este estágio favoreceu a aquisição e consolidação de conhecimentos na área da Fisioterapia Neurológica, nomeadamente sobre o Conceito de Bobath e a avaliação da funcionalidade. São apresentados três casos clínicos de pacientes com sequelas de AVC que permitiram treinar a aplicação das escalas de funcionalidade, desenvolver o raciocínio clínico, aplicar as estratégias selecionadas e refletir sobre a eficácia da intervenção. Discussão: Embora não exista evidência robusta da superioridade do Conceito de Bobath em relação a outras abordagens, a sua filosofia facilita a avaliação e a tomada de decisão numa perspetiva holística sem menosprezar a individualidade de cada paciente. Das três escalas de funcionalidade aplicadas a Motor Assessement Scale é a única a levar em consideração a qualidade do movimento, o que a torna mais sensível a pequenas evoluções facilitando a mensuração adequada dos objetivos da intervenção. Conclusão: A realização deste estágio foi um período de aprendizagem importante e uma experiência enriquecedora no aspeto clínico, científico e académico.ABSTRACT - Introduction: Neurological Physiotherapy is an essential intervention area as there are more and more patients with sequelae resulting from injuries to the central nervous system requiring physiotherapy care, namely patients with stroke as the incidence rates are high and mortality has been decreasing with medical advances. On the other hand, current knowledge in the field of neuroscience allows the intervention of the physiotherapist to be based on evidence Objectives: To deepen knowledge, skills, and competencies in Neurological Physiotherapy in adult patients; essentially intervening in patients with sequelae of stroke, developing the model of clinical reasoning and investigating the effectiveness of the Bobath Concept in the functionality of patients after stroke. Methodology: The internship articulated the research aspect, the pedagogical dimension, and the clinical practice; it took place at Hospital Curry Cabral (Centro Hospitalar Lisboa Central) with adult patients undergoing physical therapy, inpatient or outpatient, due to neurological pathology and more specifically with patients with stroke sequelae; lasted 200 hours. Three scales of functionality were selected (the Barthel modified indicator the Functional Independence Measure and the Motor Assessment Scale) for the evaluation of the clinical cases followed and the approach in physiotherapy was based on the Bobath Concept. Results: This internship allowed the acquisition and consolidation of knowledge in the area of Neurological Physiotherapy, namely on the Bobath Concept and the evaluation of functionality. Three clinical cases of patients with stroke sequelae are presented, which allowed to train the application of the selected functionality scales, develop clinical reasoning and reflect on the effectiveness of the intervention. Discussion: While there is no robust evidence of the superiority of the Bobath Concept over other approaches, its philosophy facilitates assessment and decision-making from a holistic perspective without underestimating the individuality of each patient. Of the three scales of functionality applied the Motor Assessment Scale, is the only one to consider the quality of the movement, which makes it more sensitive to small developments, facilitating the adequate measurement of the intervention goals. Conclusion: This internship was an important learning period and an enriching experience in the clinical, scientific, and academic aspects.N/

Mortality Measurement Matters: Improving Data Collection and Estimation Methods for Child and Adult Mortality

Colin Mathers and Ties Boerma discuss three research articles in PLoS Medicine that address the measurement and analysis of child and adult mortality data collected through death registration, censuses, and household surveys

Barriers and incentives to orphan care in a time of AIDS and economic crisis: a cross-sectional survey of caregivers in rural Zimbabwe

BACKGROUND: Africa is in an orphan-care crisis. In Zimbabwe, where one-fourth of adults are HIV-positive and one-fifth of children are orphans, AIDS and economic decline are straining society's ability to care for orphans within their extended families. Lack of stable care is putting thousands of children at heightened risk of malnourishment, emotional underdevelopment, illiteracy, poverty, sexual exploitation, and HIV infection, endangering the future health of the society they are expected to sustain. METHODS: To explore barriers and possible incentives to orphan care, a quantitative cross-sectional survey in rural eastern Zimbabwe asked 371 adults caring for children, including 212 caring for double orphans, about their well-being, needs, resources, and perceptions and experiences of orphan care. RESULTS: Survey responses indicate that: 1) foster caregivers are disproportionately female, older, poor, and without a spouse; 2) 98% of non-foster caregivers are willing to foster orphans, many from outside their kinship network; 3) poverty is the primary barrier to fostering; 4) financial, physical, and emotional stress levels are high among current and potential fosterers; 5) financial need may be greatest in single-orphan AIDS-impoverished households; and 6) struggling families lack external support. CONCLUSION: Incentives for sustainable orphan care should focus on financial assistance, starting with free schooling, and development of community mechanisms to identify and support children in need, to evaluate and strengthen families' capacity to provide orphan care, and to initiate and support placement outside the family when necessary

Model based dynamics analysis in live cell microtubule images

Background: The dynamic growing and shortening behaviors of microtubules are central to the fundamental roles played by microtubules in essentially all eukaryotic cells. Traditionally, microtubule behavior is quantified by manually tracking individual microtubules in time-lapse images under various experimental conditions. Manual analysis is laborious, approximate, and often offers limited analytical capability in extracting potentially valuable information from the data. Results: In this work, we present computer vision and machine-learning based methods for extracting novel dynamics information from time-lapse images. Using actual microtubule data, we estimate statistical models of microtubule behavior that are highly effective in identifying common and distinct characteristics of microtubule dynamic behavior. Conclusion: Computational methods provide powerful analytical capabilities in addition to traditional analysis methods for studying microtubule dynamic behavior. Novel capabilities, such as building and querying microtubule image databases, are introduced to quantify and analyze microtubule dynamic behavior

Human resources requirements for highly active antiretroviral therapy scale-up in Malawi

<p>Abstract</p> <p>Background</p> <p>Twelve percent of the adult population in Malawi is estimated to be HIV infected. About 15% to 20% of these are in need of life saving antiretroviral therapy. The country has a public sector-led antiretroviral treatment program both in the private and public health sectors. Estimation of the clinical human resources needs is required to inform the planning and distribution of health professionals.</p> <p>Methods</p> <p>We obtained data on the total number of patients on highly active antiretroviral treatment program from the Malawi National AIDS Commission and Ministry of Health, HIV Unit, and the number of registered health professionals from the relevant regulatory bodies. We also estimated number of health professionals required to deliver highly active antiretroviral therapy (HAART) using estimates of human resources from the literature. We also obtained data from the Ministry of Health on the actual number of nurses, clinical officers and medical doctors providing services in HAART clinics. We then made comparisons between the human resources situation on the ground and the theoretical estimates based on explicit assumptions.</p> <p>Results</p> <p>There were 610 clinicians (396 clinical officers and 214 physicians), 44 pharmacists and 98 pharmacy technicians and 7264 nurses registered in Malawi. At the end of March 2007 there were 85 clinical officer and physician full-time equivalents (FTEs) and 91 nurse FTEs providing HAART to 95,674 patients. The human resources used for the delivery of HAART comprised 13.9% of all clinical officers and physicians and 1.1% of all nurses. Using the estimated numbers of health professionals from the literature required 15.7–31.4% of all physicians and clinical officers, 66.5–199.3% of all pharmacists and pharmacy technicians and 2.6 to 9.2% of all the available nurses. To provide HAART to all the 170,000 HIV infected persons estimated as clinically eligible would require 4.7% to 16.4% of the total number of nurses, 118.1% to 354.2% of all the available pharmacists and pharmacy technicians and 27.9% to 55.7% of all clinical officers and physicians. The actual number of health professionals working in the delivery of HAART in the clinics represented 44% to 88.8% (for clinical officers and medical doctors) and 13.6% and 47.6% (for nurses), of what would have been needed based on the literature estimation.</p> <p>Conclusion</p> <p>HAART provision is a labour intensive exercise. Although these data are insufficient to determine whether HAART scale-up has resulted in the weakening or strengthening of the health systems in Malawi, the human resources requirements for HAART scale-up are significant. Malawi is using far less human resources than would be estimated based on the literature from other settings. The impact of HAART scale-up on the overall delivery of health services should be assessed.</p

Generative Embedding for Model-Based Classification of fMRI Data

Decoding models, such as those underlying multivariate classification algorithms, have been increasingly used to infer cognitive or clinical brain states from measures of brain activity obtained by functional magnetic resonance imaging (fMRI). The practicality of current classifiers, however, is restricted by two major challenges. First, due to the high data dimensionality and low sample size, algorithms struggle to separate informative from uninformative features, resulting in poor generalization performance. Second, popular discriminative methods such as support vector machines (SVMs) rarely afford mechanistic interpretability. In this paper, we address these issues by proposing a novel generative-embedding approach that incorporates neurobiologically interpretable generative models into discriminative classifiers. Our approach extends previous work on trial-by-trial classification for electrophysiological recordings to subject-by-subject classification for fMRI and offers two key advantages over conventional methods: it may provide more accurate predictions by exploiting discriminative information encoded in ‘hidden’ physiological quantities such as synaptic connection strengths; and it affords mechanistic interpretability of clinical classifications. Here, we introduce generative embedding for fMRI using a combination of dynamic causal models (DCMs) and SVMs. We propose a general procedure of DCM-based generative embedding for subject-wise classification, provide a concrete implementation, and suggest good-practice guidelines for unbiased application of generative embedding in the context of fMRI. We illustrate the utility of our approach by a clinical example in which we classify moderately aphasic patients and healthy controls using a DCM of thalamo-temporal regions during speech processing. Generative embedding achieves a near-perfect balanced classification accuracy of 98% and significantly outperforms conventional activation-based and correlation-based methods. This example demonstrates how disease states can be detected with very high accuracy and, at the same time, be interpreted mechanistically in terms of abnormalities in connectivity. We envisage that future applications of generative embedding may provide crucial advances in dissecting spectrum disorders into physiologically more well-defined subgroups

Neural Substrate of Cold-Seeking Behavior in Endotoxin Shock

Systemic inflammation is a leading cause of hospital death. Mild systemic inflammation is accompanied by warmth-seeking behavior (and fever), whereas severe inflammation is associated with cold-seeking behavior (and hypothermia). Both behaviors are adaptive. Which brain structures mediate which behavior is unknown. The involvement of hypothalamic structures, namely, the preoptic area (POA), paraventricular nucleus (PVH), or dorsomedial nucleus (DMH), in thermoregulatory behaviors associated with endotoxin (lipopolysaccharide [LPS])-induced systemic inflammation was studied in rats. The rats were allowed to select their thermal environment by freely moving in a thermogradient apparatus. A low intravenous dose of Escherichia coli LPS (10 µg/kg) caused warmth-seeking behavior, whereas a high, shock-inducing dose (5,000 µg/kg) caused cold-seeking behavior. Bilateral electrocoagulation of the PVH or DMH, but not of the POA, prevented this cold-seeking response. Lesioning the DMH with ibotenic acid, an excitotoxin that destroys neuronal bodies but spares fibers of passage, also prevented LPS-induced cold-seeking behavior; lesioning the PVH with ibotenate did not affect it. Lesion of no structure affected cold-seeking behavior induced by heat exposure or by pharmacological stimulation of the transient receptor potential (TRP) vanilloid-1 channel (“warmth receptor”). Nor did any lesion affect warmth-seeking behavior induced by a low dose of LPS, cold exposure, or pharmacological stimulation of the TRP melastatin-8 (“cold receptor”). We conclude that LPS-induced cold-seeking response is mediated by neuronal bodies located in the DMH and neural fibers passing through the PVH. These are the first two landmarks on the map of the circuitry of cold-seeking behavior associated with endotoxin shock