217 research outputs found

    Sound production mechanism in the semiterrestrial crab Neohelice granulata (Brachyura, Varunidae)

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    Very few studies of sound production in the Brachyura have simultaneously identified the type of individuals (e.g. sex) producing acoustic signals, the structures involved in making sound and the social context. The emission and type of sound signals in Neohelice granulata were previously characterized, but the sex and the body structures involved in the sound production mechanism were not determined. In the present study, experiments conducted in the laboratory demonstrated that acoustic signals were produced by males through an up-down movement of the cheliped by rubbing the merus against the pterygostomial area of the carapace. The micromorphology of the merus showed that it has a ridge of tubercles which may act as a plectrum, while the pterygostomial area bears tubercles and might function as the pars stridens. Acoustic signals were displayed more frequently in the presence of receptive females. Agonistic encounters among males also occurred more often in the presence of receptive females. We propose that Neohelice granulata males use their chelipeds to produce sound signals in a mating context, probably to attract the receptive female and/or to repel other males when a receptive female is present. Thus, the display might have a reproductive function influencing mate choice.Fil: Sal Moyano, María Paz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Ceraulo, Maria. Consiglio Nazionale delle Ricerche; ItaliaFil: Mazzola, Salvatore. Consiglio Nazionale delle Ricerche; ItaliaFil: Buscaino, Giuseppa. Consiglio Nazionale delle Ricerche; ItaliaFil: Gavio, Maria Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentin

    Cervical cancer screening: target age bracket, screening frequency and screening method: review of recent evidence and comparison with the Portuguese performance indicator

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    Esta revisão teve por objetivo avaliar a força de evidência do indicador de desempenho português relativo ao rastreio do Câncer do Colo do Útero (CCU): (1) limites etários das mulheres da população geral que o devem realizar, a (2) periodicidade com que deve ser realizado e (3) qual o melhor exame de rastreio. Foram pesquisados os seguintes termos MeSH: vaginal smears, age groups, periodicity, methods, uterine cervical cancer. Foram excluídos os artigos que não abordavam o objetivo da investigação ou que não fossem redigidos em Inglês, Português ou Espanhol. Para interpretar os artigos selecionados foi utilizada a classificação SORT. Foram encontrados 197 artigos, dos quais seleccionados 9: 1 revisão sistemática (RS), 1 estudo clínico controlado aleatorizado, 2 estudos observacionais retrospectivos e 5 normas de orientação clínica (NOC). Os autores optaram por incluir nesta revisão mais 4 NOCs e 2 RSs por considerarem ser relevantes para a população Portuguesa, apesar de não resultarem da pesquisa efectuada. Os estudos sugerem realização do rastreio entre os 21 e 25 até aos 65 anos, com uma periodicidade trienal usando a citologia convencional. Existe ainda controvérsia no que toca aos 3 objetivos deste artigo (limites etários, frequência e método).The scope of this review was to assess the strength of evidence of Portuguese performance indicators on Cervical Cancer screening: (1) age group of the women that should be screened for cervical cancer; (2) frequency of screening; and (3) the best method for screening. The following MeSH terms were searched: vaginal smears, age groups, periodicity, methods, uterine cervical cancer. Articles not reflecting the study objectives or not available in English, Portuguese or Spanish were excluded. The SORT classification was used to rate the articles selected.Of the 197 articles found, 9 that met all study criteria were selected for inclusion in this review. These included 1 systematic review, 1 randomized controlled clinical trial, 2 retrospective studies and 5 clinical guidelines. The authors also chose to include 4 clinical guidelines and two systematic reviews relevant to the Portuguese population even though they did not appear in the initial search of the literature. The studies suggest screening women between the ages of 21 to 25 years and 65 years of age, once every three years using conventional cytology. There is still controversy regarding the three objectives of this study (target age bracket, screening frequency and screening method)

    Complex life forms may arise from electrical processes

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    There is still not an appealing and testable model to explain how single-celled organisms, usually following fusion of male and female gametes, proceed to grow and evolve into multi-cellular, complexly differentiated systems, a particular species following virtually an invariant and unique growth pattern. An intrinsic electrical oscillator, resembling the cardiac pacemaker, may explain the process. Highly auto-correlated, it could live independently of ordinary thermodynamic processes which mandate increasing disorder, and could coordinate growth and differentiation of organ anlage

    'Asking the right question'. A comparison of two approaches to gathering data on 'herbals' use in survey based studies

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    BACKGROUND:Over the last decade academic interest in the prevalence and nature of herbal medicines use by pregnant women has increased significantly. Such data are usually collected by means of an administered questionnaire survey, however a key methodological limitation using this approach is the need to clearly define the scope of 'herbals' to be investigated. The majority of published studies in this area neither define 'herbals' nor provide a detailed checklist naming specific 'herbals' and CAM modalities, which limits inter-study comparison, generalisability and the potential for meta-analyses. The aim of this study was to compare the self-reported use of herbs, herbal medicines and herbal products using two different approaches implemented in succession. METHODS:Cross-sectional questionnaire surveys of women attending for their mid-trimester scan or attending the postnatal unit following live birth at the Royal Aberdeen Maternity Hospital, North-East Scotland. The questionnaire utilised two approaches to collect data on 'herbals' use, a single closed yes/no answer to the question "have you used herbs, herbal medicines and herbal products in the last three months"; and a request to tick which of a list of 40 'herbals' they had used in the same time period. RESULTS:A total of 889 responses were obtained of which 4.3% (38) answered 'yes' to herbal use via the closed question. However, using the checklist 39% (350) of respondents reported the use of one or more specific 'herbals' (p<0.0001). The 312 respondents who reported 'no' to 'herbals' use via the closed question but "yes" via the checklist consumed a total of 20 different 'herbals' (median 1, interquartile range 1-2, range 1-6). CONCLUSIONS:This study demonstrates that the use of a single closed question asking about the use of 'herbals', as frequently reported in published studies, may not yield valid data resulting in a gross underestimation of actual use

    Comparative performances of machine learning methods for classifying Crohn Disease patients using genome-wide genotyping data

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    Abstract: Crohn Disease (CD) is a complex genetic disorder for which more than 140 genes have been identified using genome wide association studies (GWAS). However, the genetic architecture of the trait remains largely unknown. The recent development of machine learning (ML) approaches incited us to apply them to classify healthy and diseased people according to their genomic information. The Immunochip dataset containing 18,227 CD patients and 34,050 healthy controls enrolled and genotyped by the international Inflammatory Bowel Disease genetic consortium (IIBDGC) has been re-analyzed using a set of ML methods: penalized logistic regression (LR), gradient boosted trees (GBT) and artificial neural networks (NN). The main score used to compare the methods was the Area Under the ROC Curve (AUC) statistics. The impact of quality control (QC), imputing and coding methods on LR results showed that QC methods and imputation of missing genotypes may artificially increase the scores. At the opposite, neither the patient/control ratio nor marker preselection or coding strategies significantly affected the results. LR methods, including Lasso, Ridge and ElasticNet provided similar results with a maximum AUC of 0.80. GBT methods like XGBoost, LightGBM and CatBoost, together with dense NN with one or more hidden layers, provided similar AUC values, suggesting limited epistatic effects in the genetic architecture of the trait. ML methods detected near all the genetic variants previously identified by GWAS among the best predictors plus additional predictors with lower effects. The robustness and complementarity of the different methods are also studied. Compared to LR, non-linear models such as GBT or NN may provide robust complementary approaches to identify and classify genetic markers
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