The Bacterial Chemotactic Response Reflects a Compromise Between Transient and Steady State Behavior

Swimming bacteria detect chemical gradients by performing temporal comparisons of recent measurements of chemical concentration. These comparisons are described quantitatively by the chemotactic response function, which we expect to optimize chemotactic behavioral performance. We identify two independent chemotactic performance criteria: in the short run, a favorable response function should move bacteria up chemoattractant gradients, while in the long run, bacteria should aggregate at peaks of chemoattractant concentration. Surprisingly, these two criteria conflict, so that when one performance criterion is most favorable, the other is unfavorable. Since both types of behavior are biologically relevant, we include both behaviors in a composite optimization that yields a response function that closely resembles experimental measurements. Our work suggests that the bacterial chemotactic response function can be derived from simple behavioral considerations, and sheds light on how the response function contributes to chemotactic performance.Comment: 19 pages, 5 figure

Do bilinguals have different concepts? The case of shape and material in Japanese L2 users of English

An experiment investigated whether Japanese speakers’ categorisation of objects and substances as shape or material is influenced by acquiring English, based on Imai and Gentner (1997). Subjects were presented with an item such as a cork pyramid and asked to choose between two other items that matched it for shape (plastic pyramid) or for material (piece of cork). The hypotheses were that for simple objects the number of shape-based categorisations would increase according to experience of English and that the preference for shape and material-based categorisations of Japanese speakers of English would differ from mono¬lingual speakers of both languages. Subjects were 18 adult Japanese users of English who had lived in English-speaking countries between 6 months and 3 years (short-stay group), and 18 who had lived in English-speaking countries for 3 years or more (long-stay group). Both groups achieved above criterion on an English vocabulary test. Results were: both groups preferred material responses for simple objects and substances but not for complex objects, in line with Japanese mono¬linguals, but the long-stay group showed more shape preference than the short-stay group and also were less different from Americans. These effects of acquiring a second language on categorisation have implications for conceptual representation and methodology

Condições demográficas e socioeconômicas associadas à insegurança alimentar em domicílios de Campinas, SP

To evaluate the association of food insecurity with demographic and socioeconomic conditions in households in Campinas, São Paulo state, Brazil. Methods: This is a cross-sectional study conducted on a representative sample of the urban population of the Southern, Southwestern, and Northwestern Health Districts of Campinas, between 2011-2012. Characteristics of the head of household, family history and household patterns were investigated. The dependent variable was food security condition, categorized as food security, mild food insecurity, and moderate/severe food insecurity. All independent variables with p-value <0.20 in the bivariate multinomial logistic regression were included in the final model of multiple multinomial logistic regression, adjusted to household head age; the remaining variables had p-value <0.05. Results: In the 691 households analyzed, there was 65% of food security, 27.9% of mild food insecurity, and 7.1% of moderate/severe food insecurity. The conditions associated with mild food insecurity were monthly per capita income less than the minimum wage, household head unemployed for more than six months between 2004-2010, living in properties given to the family/occupied/other, and density higher than two people per bedroon. The moderate/severe food insecurity was associated with informal employment condition of the household head and the presence of a beneficiary of the Bolsa Família (Family Allowance Program), a cash transfer-type program, in the household. The higher the score of the consumer goods, the lower the probability of mild food insecurity or moderate/severe food insecurity. There was a higher probability of mild food insecurity and moderate/severe food insecurity in unfinished masonry-built houses/other. Conclusion: More than one third of the households investigated experienced some form of food insecurity. Mild food insecurity was associated with demographic conditions, while moderate/severe food insecurity was associated with socioeconomic conditions, especially those related to the household head296845857FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPSem informaçãoAvaliar a associação da insegurança alimentar com as condições demográficas e socioeconômicas em domicílios de Campinas (SP). Métodos: Estudo transversal com amostra representativa da população urbana dos Distritos de Saúde Sul, Sudoeste e Noroeste de Campinas, realizado entre 2011-2012. Estudaram-se as características do chefe de família, dos antecedentes familiares e do domicílio. A variável dependente foi condição de segurança alimentar, categorizada em segurança alimentar, insegurança alimentar leve e insegurança alimentar moderada/grave. Todas as variáveis independentes com p-valor<0,20 na regressão logística multinomial bivariada foram incluídas no modelo final de regressão logística multinomial múltipla, ajustado pela idade do chefe da família, permanecendo aquelas com p<0,05. Resultados: Nos 691 domicílios analisados, houve 65,0% em segurança alimentar, 27,9% em insegurança alimentar leve e 7,1% em insegurança alimentar moderada/grave. As condições associadas à insegurança alimentar leve foram renda familiar mensal per capita menor que um salário mínimo, desemprego do chefe da família por mais de seis meses entre 2004-2010, residir em domicílios de condição cedido/invasão/outro e com densidade maior que duas pessoas por dormitório. A insegurança alimentar moderada/grave esteve associada à informalidade do emprego do chefe da família e ter titular do Bolsa Família no domicílio. Quanto maior o escore de bens de consumo, menor foi a chance de insegurança alimentar leve ou moderada/grave, enquanto que houve maior chance da presença de qualquer tipo de insegurança alimentar nos domicílios construídos com alvenaria inacabada/outros. Conclusão: Mais de um terço dos domicílios apresentam alguma forma de insegurança alimentar. A insegurança alimentar leve está associada às condições demográficas, enquanto que a moderada/grave associa-se às condições socioeconômicas, principalmente relacionadas ao chefe da famíli

The experience of long-term opiate maintenance treatment and reported barriers to recovery: A qualitative systematic review

Background/Aim: To inform understanding of the experience of long-term opiate maintenance and identify barriers to recovery. Methods: A qualitative systematic review. Results: 14 studies in 17 papers, mainly from the USA (65%), met inclusion criteria, involving 1,088 participants. Studies focused on methadone prescribing. Participants reported stability; however, many disliked methadone. Barriers to full recovery were primarily ‘inward focused'. Conclusion: This is the first review of qualitative literature on long-term maintenance, finding that universal service improvements could be made to address reported barriers to recovery, including involving ex-users as positive role models, and increasing access to psychological support. Treatment policies combining harm minimisation and abstinence-orientated approaches may best support individualised recovery

Household food insecurity in Brazilian adolescents : a validation study

Objetivo: os objetivos do trabalho foram avaliar a validade interna e a capacidade preditiva da escala de segurança alimentar de seis itens aplicada a adolescentes. Métodos: foi um estudo transversal com amostra representativa de adolescentes brasileiros (N=14.690), realizado em escolas públicas e privadas nas 26 capitais de estados brasileiros e no Distrito Federal por meio de questionário online. Resultados: a maior parte dos respondentes era do sexo feminino (53,2%), com idade média de 14,4 anos, sendo 72,7% de escolas públicas. O comportamento da escala, observado pelo modelo de Rasch, foi melhor sem o item cinco, apresentando valores ótimos de Infit e nível de severidade crescente entre os itens. O alfa de Cronbach foi 0,77, e as análises do funcionamento diferencial dos itens mostraram comportamento dos itens semelhante entre os subgrupos avaliados. A análise fatorial mostrou a unidimensionalidade do instrumento. Conclusão: foi proposta a retirada do item cinco e novos pontos de corte para a escala curta de segurança alimentar. A escala curta de segurança alimentar é válida e confiável para mensurar insegurança alimentar domiciliar entre adolescentes brasileiros.Objective: the objective of this study was to evaluate the internal and predictive validity of a six-item household food insecurity scale to measure food insecurity in Brazilian adolescents. Methods: a cross-sectional study with a representative sample of Brazilian adolescents (N=14,690) was conducted in public and private schools in 26 state capitals and in the Federal District of Brazil using an online questionnaire. Results: most respondents were female (53.2%) with mean age of 14.4 years, and 72.7% of them attended public schools. The psychometric properties of the scale, assessed using the Rasch model, showed better response rates without the item five, exhibiting optimal Infit statistics and an increasing level of severity among the items. Cronbach's á was 0.767. Differential item functioning analyses showed similar behavior between the items in the subgroups evaluated. Factor analysis confirmed the unidimensionality of the scale. Conclusion: this study proposes the removal of the item five and the inclusion of new cut-off points for this short form of the scale. The Household Food Security Scale (short form) is valid and reliable to measure household food insecurity in Brazilian adolescents

Fraturas da clavicula - incidencia de lesao do nervo supraclavicular

OBJECTIVE:To analyze retrospectively 309 fractures in the clavicle and the relation with injury of the supraclavicular nerve after trauma.METHODS:It was analyzed 309 patients with 312 clavicle fractures. The Edinburgh classification was used. Four patients had fractures in the medial aspect of the clavicle, 33 in the lateral aspect and 272 in the diaphyseal aspect and three bilateral fractures.RESULTS:255 patients were analyzed and five had paresthesia in the anterior aspect of the thorax. Four patients had type 2 B2 fracture and one type 2 B1 fracture. All patients showed spontaneous improvement, in the mean average of 3 months after the trauma.CONCLUSION:Clavicle fractures and/ or shoulder surgeries can injure the lateral, intermediary or medial branches of the supraclavicular nerve and cause alteration of sensibility in the anterior aspect of the thorax. Knowledge of the anatomy of the nerve branches helps avoid problems in this region.OBJETIVO:Analisar retrospectivamente 309 fraturas da clavícula e sua relação com a lesão do nervo supraclavicular após trauma.MÉTODOS:Foram analisados 309 pacientes com 312 fraturas da clavícula. Foi usada a classificação de Edinburgh. Quatro pacientes apresentavam fraturas da região medial da clavícula, 33 da região lateral, 272 da região diafisária e três com fraturas bilaterais.RESULTADOS:Foram analisados 255 pacientes e cinco apresentavam parestesia na região anterior do tórax. Quatro pacientes apresentaram fratura do tipo 2 B2 e um do tipo 2 B1. Todos os pacientes tiveram melhoria espontânea, em média de três meses após o trauma.CONCLUSÃO:Fraturas da clavícula e/ou cirurgias no ombro podem lesar os ramos lateral, intermediário ou medial do nervo supraclavicular e causar alteração da sensibilidade na região anterior do tórax. O conhecimento da anatomia dos ramos nervosos ajuda a evitar problemas nessa região.Universidade Federal de São Paulo (UNIFESP) Escola Paulista de MedicinaHospital Santa TeresaUFRJ School of Medicine Department of Orthopedics and TraumatologyHospital Estadual de Traumatologia e Ortopedia Dona LinduInstituto Nacional de Ortopedia e TraumatologiaUNIFESP, EPMSciEL

Chemotaxis When Bacteria Remember: Drift versus Diffusion

{\sl Escherichia coli} ({\sl E. coli}) bacteria govern their trajectories by switching between running and tumbling modes as a function of the nutrient concentration they experienced in the past. At short time one observes a drift of the bacterial population, while at long time one observes accumulation in high-nutrient regions. Recent work has viewed chemotaxis as a compromise between drift toward favorable regions and accumulation in favorable regions. A number of earlier studies assume that a bacterium resets its memory at tumbles -- a fact not borne out by experiment -- and make use of approximate coarse-grained descriptions. Here, we revisit the problem of chemotaxis without resorting to any memory resets. We find that when bacteria respond to the environment in a non-adaptive manner, chemotaxis is generally dominated by diffusion, whereas when bacteria respond in an adaptive manner, chemotaxis is dominated by a bias in the motion. In the adaptive case, favorable drift occurs together with favorable accumulation. We derive our results from detailed simulations and a variety of analytical arguments. In particular, we introduce a new coarse-grained description of chemotaxis as biased diffusion, and we discuss the way it departs from older coarse-grained descriptions.Comment: Revised version, journal reference adde

The glycolytic enzyme phosphofructokinase-1 assembles into filaments.

Despite abundant knowledge of the regulation and biochemistry of glycolytic enzymes, we have limited understanding on how they are spatially organized in the cell. Emerging evidence indicates that nonglycolytic metabolic enzymes regulating diverse pathways can assemble into polymers. We now show tetramer- and substrate-dependent filament assembly by phosphofructokinase-1 (PFK1), which is considered the "gatekeeper" of glycolysis because it catalyzes the step committing glucose to breakdown. Recombinant liver PFK1 (PFKL) isoform, but not platelet PFK1 (PFKP) or muscle PFK1 (PFKM) isoforms, assembles into filaments. Negative-stain electron micrographs reveal that filaments are apolar and made of stacked tetramers oriented with exposed catalytic sites positioned along the edge of the polymer. Electron micrographs and biochemical data with a PFKL/PFKP chimera indicate that the PFKL regulatory domain mediates filament assembly. Quantified live-cell imaging shows dynamic properties of localized PFKL puncta that are enriched at the plasma membrane. These findings reveal a new behavior of a key glycolytic enzyme with insights on spatial organization and isoform-specific glucose metabolism in cells

Mining the Mind Research Network: A Novel Framework for Exploring Large Scale, Heterogeneous Translational Neuroscience Research Data Sources

A neuroinformatics (NI) system is critical to brain imaging research in order to shorten the time between study conception and results. Such a NI system is required to scale well when large numbers of subjects are studied. Further, when multiple sites participate in research projects organizational issues become increasingly difficult. Optimized NI applications mitigate these problems. Additionally, NI software enables coordination across multiple studies, leveraging advantages potentially leading to exponential research discoveries. The web-based, Mind Research Network (MRN), database system has been designed and improved through our experience with 200 research studies and 250 researchers from seven different institutions. The MRN tools permit the collection, management, reporting and efficient use of large scale, heterogeneous data sources, e.g., multiple institutions, multiple principal investigators, multiple research programs and studies, and multimodal acquisitions. We have collected and analyzed data sets on thousands of research participants and have set up a framework to automatically analyze the data, thereby making efficient, practical data mining of this vast resource possible. This paper presents a comprehensive framework for capturing and analyzing heterogeneous neuroscience research data sources that has been fully optimized for end-users to perform novel data mining