Reinforcement learning in dendritic structures

The discovery of binary dendritic events such as local NMDA spikes in dendritic subbranches led to the suggestion that dendritic trees could be computationally equivalent to a 2-layer network of point neurons, with a single output unit represented by the soma, and input units represented by the dendritic branches. Although this interpretation endows a neuron with a high computational power, it is functionally not clear why nature would have preferred the dendritic solution with a single but complex neuron, as opposed to the network solution with many but simple units. We show that the dendritic solution has a distinguished advantage over the network solution when considering different learning tasks. Its key property is that the dendritic branches receive an immediate feedback from the somatic output spike, while in the corresponding network architecture the feedback would require additional backpropagating connections to the input units. Assuming a reinforcement learning scenario we formally derive a learning rule for the synaptic contacts on the individual dendritic trees which depends on the presynaptic activity, the local NMDA spikes, the somatic action potential, and a delayed reinforcement signal. We test the model for two scenarios: the learning of binary classifications and of precise spike timings. We show that the immediate feedback represented by the backpropagating action potential supplies the individual dendritic branches with enough information to efficiently adapt their synapses and to speed up the learning process

Pulsed thermal emission from the accreting pulsar XMMU J054134.7-682550

Aims. Soft X-ray excesses have been detected in several Be/X-ray binaries and interpreted as the signature of hard X-ray reprocessing in the inner accretion disk. The system XMMU J054134.7-682550, located in the LMC, featured a giant Type II outburst in August 2007. The geometry of this system can be understood by studying the response of the soft excess emission to the hard X-ray pulses. Methods. We have analyzed series of simultaneous observations obtained with XMM-Newton/EPIC-MOS and RXTE/PCA in order to derive spectral and temporal characteristics of the system, before, during and after the giant outburst. Spectral fits were performed and a timing analysis has been carried out. Spectral variability, spin period evolution and energy dependent pulse shapes are analysed. Results. The outburst (L_X = 3* 10^38 erg/s \approx L_EDD) spectrum could be modeled successfully using a cutoff powerlaw, a cold disk emission, a hot blackbody, and a cyclotron absorption line. The magnetic field and magnetospheric radius could be constrained. The thickness of the inner accretion disk is broadened to a width of 75 km. The hot blackbody component features sinusoidal modulations indicating that the bulk of the hard X-ray emission is emitted preferentially along the magnetic equator. The spin period of the pulsar decreased very significantly during the outburst. This is consistent with a variety of neutron star equations of state and indicates a very high accretion rate.Comment: 6 pages. Accepted for publication in A&

Radiocarbon dating of methane and carbon dioxide evaded from a temperate peatland stream

Streams draining peatlands export large quantities of carbon in different chemical forms and are an important part of the carbon cycle. Radiocarbon (14C) analysis/dating provides unique information on the source and rate that carbon is cycled through ecosystems, as has recently been demonstrated at the air-water interface through analysis of carbon dioxide (CO2) lost from peatland streams by evasion (degassing). Peatland streams also have the potential to release large amounts of methane (CH4) and, though 14C analysis of CH4 emitted by ebullition (bubbling) has been previously reported, diffusive emissions have not. We describe methods that enable the 14C analysis of CH4 evaded from peatland streams. Using these methods, we investigated the 14C age and stable carbon isotope composition of both CH4 and CO2 evaded from a small peatland stream draining a temperate raised mire. Methane was aged between 1617-1987 years BP, and was much older than CO2 which had an age range of 303-521 years BP. Isotope mass balance modelling of the results indicated that the CO2 and CH4 evaded from the stream were derived from different source areas, with most evaded CO2 originating from younger layers located nearer the peat surface compared to CH4. The study demonstrates the insight that can be gained into peatland carbon cycling from a methodological development which enables dual isotope (14C and 13C) analysis of both CH4 and CO2 collected at the same time and in the same way

Genetic and biochemical analyses of chromosome and plasmid gene homologues encoding ICL and ArCP domains in Vibrioanguillarum strain 775

Anguibactin, the siderophore produced by Vibrio anguillarum 775 is synthesized from 2,3-dihydroxybenzoic acid (DHBA), cysteine and hydroxyhistamine via a nonribosomal peptide synthetase (NRPS) mechanism. Most of the genes encoding anguibactin biosynthetic proteins are harbored by the pJM1 plasmid. In this work we report the identification of a homologue of the plasmid-encoded angB on the chromosome of strain 775. The product of both genes harbor an isochorismate lyase (ICL) domain that converts isochorismic acid to 2,3-dihydro-2,3-dihydroxybenzoic acid, one of the steps of DHBA synthesis. We show in this work that both ICL domains are functional in the production of DHBA in V. anguillarum as well as in E. coli. Substitution by alanine of the aspartic acid residue in the active site of both ICL domains completely abolishes their isochorismate lyase activity in vivo. The two proteins also carry an aryl carrier protein (ArCP) domain. In contrast with the ICL domains only the plasmid encoded ArCP can participate in anguibactin production as determined by complementation analyses and site-directed mutagenesis in the active site of the plasmid encoded protein, S248A. The site-directed mutants, D37A in the ICL domain and S248A in the ArCP domain of the plasmid encoded AngB were also tested in vitro and clearly show the importance of each residue for the domain function and that each domain operates independently.

BASE NACIONAL COMUM CURRICULAR

O presente estudo busca reunir informações acerca da Base Nacional Comum Curricular, demonstrando que essa Base define as competências e conhecimentos essenciais para orientar a formação do aluno de ensino médio.  O presente artigo tem por finalidade, expor analise com referencia a capacidade da BNCC de orientar os alunos na escolha das áreas de formação e dos itinerários formativos, após um levantamento de pesquisas por meio do Google Acadêmico e varias leituras em relação a BNCC.  O artigo expõe as analises feitas com base nas propostas da BNCC, de opiniões e criticas de profissionais da educação,  no sentido de esmiuçar os meandros da nova fase da educação no Brasil, que passará por transformações no anos vindouros, seja na parte de metodologia do ensino, seja na área do desenvolvimento pedagógico. Tema que no momento traz preocupações, sobre a autonomia das redes de ensino em construir e disponibilizar seus próprios currí­culos.  O estudo concluiu que É importantí­ssimo que os alunos compreendam cada competência, é importante também conversar sobre cada uma delas, discutir com os alunos o que eles estão aprendendo, e porque estão aprendendo, para que entendam o sentido, a importância de cada área de formação e que possam estar abertos a colaborar para que juntos os estudantes possam ajudar a desenvolver o coletivo, sendo protagonistas de suas historias. Se torna muito importante o diálogo e as discussões sobre os projetos polí­ticos pedagógicos das escolas com todos os professores, gestores e colaboradores, para que a concepção de educação possa ser compreendida e incorporada, tornar-se salutar, aproveitar este momento para reflexão sobre a formação do ser humano que é  o aluno nesta fase da sua vida.This study seeks to gather information about the Common National Curriculum Base, demonstrating that this Base defines the skills and knowledge essential to guide the education of high school students. This article aims to expose analysis with reference to the ability of BNCC to guide students in choosing areas of training and training itineraries, following a survey through Google Scholar and various readings in relation to BNCC. The article exposes the analyzes made based on BNCC proposals, opinions and criticisms of education professionals, in order to scrutinize the intricacies of the new phase of education in Brazil, which will undergo changes in the coming years, either in the methodology part of the program. teaching, whether in the area of "‹"‹pedagogical development. A topic that currently raises concerns about the autonomy of education networks in building and making their own curricula available. The study concluded that It is very important that students understand each competency, it is also important to talk about each competency, discuss with students what they are learning, and why they are learning, so that they understand the meaning, the importance of each area of "‹"‹training. and that they can be open to collaborate so that together students can help develop the collective, being protagonists of their stories. It is very important the dialogue and discussions about the pedagogical political projects of schools with all teachers, managers and collaborators, so that the conception of education can be understood and incorporated, become healthy, take this moment to reflect on the formation of the human being who is the student at this stage of his life.Este estudio busca recopilar información sobre la Base de Currí­culo Nacional Común, demostrando que esta Base define las habilidades y conocimientos esenciales para guiar la educación de los estudiantes de secundaria. Este artí­culo tiene como objetivo exponer el análisis con referencia a la capacidad de BNCC para guiar a los estudiantes en la elección de áreas de capacitación e itinerarios de capacitación, siguiendo una encuesta a través de Google Scholar y varias lecturas en relación con BNCC. El artí­culo expone los análisis realizados en base a las propuestas, opiniones y crí­ticas de BNCC a los profesionales de la educación, con el fin de analizar las complejidades de la nueva fase de la educación en Brasil, que sufrirá cambios en los próximos años, ya sea en la parte metodológica del programa. enseñanza, ya sea en el área del desarrollo pedagógico. Un tema que actualmente plantea preocupaciones sobre la autonomí­a de las redes educativas en la construcción y puesta a disposición de sus propios planes de estudio. El estudio concluyó que es muy importante que los estudiantes entiendan cada competencia, también es importante hablar sobre cada competencia, discutir con los estudiantes lo que están aprendiendo y por qué están aprendiendo, para que entiendan el significado, la importancia de cada área de capacitación. y que pueden estar abiertos a colaborar para que juntos los estudiantes puedan ayudar a desarrollar el colectivo, siendo protagonistas de sus historias. Es muy importante el diálogo y las discusiones sobre los proyectos polí­ticos pedagógicos de las escuelas con todos los docentes, gerentes y colaboradores, para que la concepción de la educación se pueda comprender e incorporar, volverse saludable, aproveche este momento para reflexionar sobre la formación. del ser humano que es el estudiante en esta etapa de su vida

Cholangiocarcinoma: Epidemiology and risk factors

Cholangiocarcinoma (CCA) is a heterogeneous disease arising from a complex interaction between host-specific genetic background and multiple risk factors. Globally, CCA incidence rates exhibit geographical variation, with much higher incidence in parts of the Eastern world compared to the West. These differences are likely to reflect differences in geographical risk factors as well as genetic determinants. Of note, over the past few decades, the incidence rates of CCA appear to change and subtypes of CCA appear to show distinct epidemiological trends. These trends need to be interpreted with caution given the issues of diagnosis, recording and coding of subtypes of CCA. Epidemiological evidences suggest that in general population some risk factors are less frequent but associated with a higher CCA risk, while others are more common but associated with a lower risk. Moreover, while some risk factors are shared by intrahepatic and both extrahepatic forms, others seem more specific for one of the two forms. Currently some pathological conditions have been clearly associated with CCA development, and other conditions are emerging; however, while their impact in increasing CCA risk as single etiological factors has been provided in many studies, less is known when two or more risk factors co-occur in the same patient. Moreover, despite the advancements in the knowledge of CCA aetiology, in Western countries about 50% of cases are still diagnosed without any identifiable risk factor. It is therefore conceivable that other still undefined etiologic factors are responsible for the recent increase of CCA (especially iCCA) incidence worldwide

Implementation of routine outcome measurement in child and adolescent mental health services in the United Kingdom: a critical perspective

The aim of this commentary is to provide an overview of clinical outcome measures that are currently recommended for use in UK Child and Adolescent Mental Health Services (CAMHS), focusing on measures that are applicable across a wide range of conditions with established validity and reliability, or innovative in their design. We also provide an overview of the barriers and drivers to the use of Routine Outcome Measurement (ROM) in clinical practice

Gender-Related Differences in the Prevalence of Cardiovascular Disease Risk Factors and their Correlates in Urban Tanzania.

\ud Urban areas in Africa suffer a serious problem with dual burden of infectious diseases and emerging chronic diseases such as cardiovascular diseases (CVD) and diabetes which pose a serious threat to population health and health care resources. However in East Africa, there is limited literature in this research area. The objective of this study was to examine the prevalence of cardiovascular disease risk factors and their correlates among adults in Temeke, Dar es Salaam, Tanzania. Results of this study will help inform future research and potential preventive and therapeutic interventions against such chronic diseases. The study design was a cross sectional epidemiological study. A total of 209 participants aged between 44 and 66 years were included in the study. A structured questionnaire was used to evaluate socioeconomic and lifestyle characteristics. Blood samples were collected and analyzed to measure lipid profile and fasting glucose levels. Cardiovascular risk factors were defined using World Health Organization criteria. The age-adjusted prevalence of obesity (BMI > or = 30) was 13% and 35%, among men and women (p = 0.0003), respectively. The prevalence of abdominal obesity was 11% and 58% (p < 0.0001), and high WHR (men: >0.9, women: >0.85) was 51% and 73% (p = 0.002) for men and women respectively. Women had 4.3 times greater odds of obesity (95% CI: 1.9-10.1), 14.2-fold increased odds for abdominal adiposity (95% CI: 5.8-34.6), and 2.8 times greater odds of high waist-hip-ratio (95% CI: 1.4-5.7), compared to men. Women had more than three-fold greater odds of having metabolic syndrome (p = 0.001) compared to male counterparts, including abdominal obesity, low HDL-cholesterol, and high fasting blood glucose components. In contrast, female participants had 50% lower odds of having hypertension, compared to men (95%CI: 0.3-1.0). Among men, BMI and waist circumference were significantly correlated with blood pressure, triglycerides, total, LDL-, and HDL-cholesterol (BMI only), and fasting glucose; in contrast, only blood pressure was positively associated with BMI and waist circumference in women. The prevalence of CVD risk factors was high in this population, particularly among women. Health promotion, primary prevention, and health screening strategies are needed to reduce the burden of cardiovascular disease in Tanzania.\u