985 resultados para Individual ability


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The spider crab Maja squinado is an endangered Mediterranean species; therefore, culturing it successfully is essential for developing restocking programs. The survival, growth and development of post-larval stages (juvenile crabs, C1-C8) were studied using larvae obtained from adult individuals collected in the Catalan Sea. The juvenile crab stages were cultured individually from a megalopal stage using a semi-open recirculation system to obtain the precise growth data of each juvenile crab stage until C8. Development up to C8 at 20ºC lasted 154±10 days. Survival from C1 to C8 was 5.8 %. Moult increment values in cephothoracic length were similar in all the crab stages (21-35 %). Intermoult duration (9±1 in C1-C2 to 51±8 days in C7-C8) increased sharply from juvenile stage 5. Males and females can be distinguished from C4 based on sexual dimorphism in the pleopods and the presence of gonopores. The allometric growth of the pleon is sex-dependent from C4, with females showing positive allometry and males isometric growth. The juvenile growth rate was lower compared with that of the previously studied Atlantic species Maja brachydactyla.

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BACKGROUND: Community-acquired pneumonia (CAP) is a serious cause of morbidity among children in developed countries. The real impact of 7-valent pneumococcal conjugate vaccine (PCV7) on pneumococcal pneumonia is difficult to assess accurately. METHODS: Children aged ≤16 years with clinical and radiological pneumonia were enrolled in a multicenter prospective study. Children aged ≤16 years admitted for a minor elective surgery was recruited as controls. Nasopharyngeal samples for PCR serotyping of S. pneumoniae were obtained in both groups. Informations on age, gender, PCV7 vaccination status, day care/school attendance, siblings, tobacco exposure were collected. RESULTS: In children with CAP (n=236), 54% of the nasopharyngeal swabs were PCR-positive for S. pneumoniae compared to 32% in controls (n=105) (p=0.003). Serotype 19A was the most common pneumococcal serotype carried in children with CAP (13%) and in controls (15%). Most common serotypes were non-vaccine types (39.4% for CAP and 47.1% for controls) and serotypes included only in PCV13 (32.3% for CAP and 23.5% for controls). There was no significant difference in vaccine serotype distribution between the two groups. In fully vaccinated children with CAP, the proportion of serotypes carried only in PCV13 was higher (51.4%) than in partially vaccinated or non vaccinated children (27.6% and 28.6% respectively, p=0.037). CONCLUSIONS: Two to 4 years following introduction of PCV7, predominant S. pneumoniae serotypes carried in children with CAP were non PCV7 serotypes, and the 6 new serotypes included in PCV13 accounted for 51.4% of carried serotypes in fully vaccinated children.

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Root diseases caused by fungal pathogens can be suppressed by certain rhizobacteria that effectively colonize the roots and produce extracellular antifungal compounds. To be effective, biocontrol bacteria need to be present at sufficiently high cell densities. These conditions favor the operation of positive feedback mechanisms that control the production of antifungal compounds in biocontrol strains of fluorescent pseudomonads, via both transcriptional and post-transcriptional mechanisms.

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The conflict between siblings over how parental resources are divided has promoted the evolution of specific behaviour to outcompete each other. Young animals look out for parents' arrival in order to start begging as quickly as possible, since a rapid begging reaction increases the likelihood of being fed before nestmates. If the young can physically intercept the parents, selection might be operating on the offspring ability to monitor parent arrival (vigilance towards parents) and any sudden modifications in siblings' behaviour (vigilance towards siblings). To investigate the adaptive value of nestling vigilance in the context of family interactions, we recorded which direction barn owl Tyto alba siblings were facing in 89 two-chick broods before the first parental feeding visit of the night. Nestlings were more vigilant towards nest entrance than expected by chance suggesting that vigilance towards parents is an important component of sibling competition. When positioned near the nest-box entrance where parents predictably deliver food, the younger individual (i.e. junior) looked more towards the entrance than its older sibling. Thus, when the likelihood of obtaining a food item is relatively high, juniors are more vigilant than seniors to detect the incoming parent. When positioned at the back of the nest, the senior looked relatively more frequently towards its sibling than the junior did in the same situation. This suggests that when the likelihood of obtaining a food item is relatively low, seniors are more vigilant than juniors to observe their sibling. Because vigilance was not related to hunger level and prey obtaining, we propose the hypothesis that vigilance towards parents and siblings only indirectly influences the outcome of sibling competition.

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The aim of the present study was to investigate whether trainees' performance on a virtual reality angled laparoscope navigation task correlates with scores obtained on a validated conventional test of spatial ability. 56 participants of a surgery workshop performed an angled laparoscope navigation task on the Xitact LS 500 virtual reality Simulator. Performance parameters were correlated with the score of a validated paper-and-pencil test of spatial ability. Performance at the conventional spatial ability test significantly correlated with performance at the virtual reality task for overall task score (p < 0.001), task completion time (p < 0.001) and economy of movement (p = 0.035), not for endoscope travel speed (p = 0.947). In conclusion, trainees' performance in a standardized virtual reality camera navigation task correlates with their innate spatial ability. This VR session holds potential to serve as an assessment tool for trainees.

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This project deals with the generation of profitability and the distribution of its benefits. Inspired by Davis (1947, 1955), we define profitability as the ratio of revenue to cost. Profitability is not as popular a measure of business financial performance as profit, the difference between revenue and cost. Regardless of its popularity, however, profitability is surely a useful financial performance measure. Our primary objective in this project is to identify the factors that generate change in profitability. One set of factors, which we refer to as sources, consists of changes in quantities and prices of outputs and inputs. Individual quantity changes aggregate to the overall impact of quantity change on profitability change, which we call productivity change. Individual price changes aggregate to the overall impact of price change on profitability change, which we call price recovery change. In this framework profitability change consists exclusively of productivity change and price recovery change. A second set of factors, which we refer to as drivers, consists of phenomena such as technical change, change in the efficiency of resource allocation, and the impact of economies of scale. The ability of management to harness these factors drives productivity change, which is one component of profitability change. Thus the term sources refers to quantities and prices of individual outputs and inputs, whose changes influence productivity change or price recovery change, either of which influences profitability change. The term drivers refers to phenomena related to technology and management that influence productivity change (but not price recovery change), and hence profitability change.

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Estudi prospectiu d’incidència de NF degut a la QT a pacients amb neoplàsia solida. S’estudia la validació de l’escala modificada de MASCC i utilitat de marcadors d’inflamació en l’estratificació del risc individual. Hem inclòs 54 episodis de NF. El 50% (27/54) va ser de baix risc. Predomini de BGN (73,3%). 13% van ser bacterièmics. La sensibilitat i especificitat de l’escala modificada de MASCC van ser del 56% i 54%, respectivament. El recompte baix de granulòcits prediuen bacterièmia; i els nivells baixos de IL-12, alts de PCR i de proADM, i el temps curt de neutropènia al desenvolupament de complicacions i/o de mort. L’escala modificada de MASCC va obtenir una baixa sensibilitat i especificitat. El recompte de granulòcits, nivells de PCR i proADM s’haurien d’incloure a l’escala clàssica de MASCC per incrementar la seva sensibilitat i especificitat.

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Models predicting species spatial distribution are increasingly applied to wildlife management issues, emphasising the need for reliable methods to evaluate the accuracy of their predictions. As many available datasets (e.g. museums, herbariums, atlas) do not provide reliable information about species absences, several presence-only based analyses have been developed. However, methods to evaluate the accuracy of their predictions are few and have never been validated. The aim of this paper is to compare existing and new presenceonly evaluators to usual presence/absence measures. We use a reliable, diverse, presence/absence dataset of 114 plant species to test how common presence/absence indices (Kappa, MaxKappa, AUC, adjusted D-2) compare to presenceonly measures (AVI, CVI, Boyce index) for evaluating generalised linear models (GLM). Moreover we propose a new, threshold-independent evaluator, which we call "continuous Boyce index". All indices were implemented in the B10MAPPER software. We show that the presence-only evaluators are fairly correlated (p > 0.7) to the presence/absence ones. The Boyce indices are closer to AUC than to MaxKappa and are fairly insensitive to species prevalence. In addition, the Boyce indices provide predicted-toexpected ratio curves that offer further insights into the model quality: robustness, habitat suitability resolution and deviation from randomness. This information helps reclassifying predicted maps into meaningful habitat suitability classes. The continuous Boyce index is thus both a complement to usual evaluation of presence/absence models and a reliable measure of presence-only based predictions.

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El tema de la investigación propuesto aquí, se centra en el malestar social, y la representación de éste desde un punto de vista personal y autobiográfico, algo que en estas página denomino Autorepresentación del malestar social. ¿Cómo se autorepresenta el malestar y qué prácticas artísticas se emplean para ello? ¿Cuáles son la transformaciones que provocan estas prácticas artísticas en el terreno audiovisual? En este sentido, exploraremos dos vías de análisis: por un lado nos interesa observar cuales han sido las modificaciones que el poder ha desarrollado para establecer nuevas formas de explotación, y por otro lado, veremos como estas modificaciones están generando una nueva praxis social donde las prácticas artísticas cobran un nuevo y reforzado sentido, así como una nueva capacidad política, individual y colectiva a un mismo tiempo, cargada de una fuerza transformadora capaz de componer nuevos espacios de sujeto. Analizaremos, desde la representación del yo en la vida cotidiana, el género y las relaciones interpersonales, hasta las transformaciones contemporáneas del trabajo, y los cambios en la construcción de la subjetividad. El principal elemento en el que se apoyaran nuestras investigaciones será el anàlisis de producciones audiovisuales contemporáneas y la distribución de estas en algunas de las redes de comunicación contemporáneas, intentando mostrar, de esta manera, la interacción y los efectos directos que provocan en la realidad social.

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BACKGROUND: Food allergy is a common allergic disorder--especially in early childhood. The avoidance of the allergenic food is the only available method to prevent further reactions in sensitized patients. A better understanding of the immunologic mechanisms involved in this reaction would help to develop therapeutic approaches applicable to the prevention of food allergy. OBJECTIVE: To establish a multi-cell in vitro model of sensitized intestinal epithelium that mimics the intestinal epithelial barrier to study the capacity of probiotic microorganisms to modulate permeability, translocation and immunoreactivity of ovalbumin (OVA) used as a model antigen. METHODS: Polarized Caco-2 cell monolayers were conditioned by basolateral basophils and used to examine apical to basolateral transport of OVA by ELISA. Activation of basophils with translocated OVA was measured by beta-hexosaminidase release assay. This experimental setting was used to assess how microorganisms added apically affected these parameters. Basolateral secretion of cytokine/chemokines by polarized Caco-2 cell monolayers was analysed by ELISA. RESULTS: Basophils loaded with OVA-specific IgE responded to OVA in a dose-dependent manner. OVA transported across polarized Caco-2 cell monolayers was found to trigger basolateral basophil activation. Microorganisms including lactobacilli and Escherichia coli increased transepithelial electrical resistance while promoting OVA passage capable to trigger basophil activation. Non-inflammatory levels of IL-8 and thymic stromal lymphopoietin were produced basolaterally by Caco-2 cells exposed to microorganisms. CONCLUSION: The complex model designed in here is adequate to learn about the consequence of the interaction between microorganisms and epithelial cells vis-a-vis the barrier function and antigen translocation, two parameters essential to mucosal homeostasis. It can further serve as a direct tool to search for microorganisms with anti-allergic and anti-inflammatory properties.

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Transmission of Leishmania was studied in 27 coffee plantations in the Brazilian State of Minas Gerais. Eighteen females and six males (11.6% of the people tested), aged between 7-65 gave a positive response to the Montenegro skin test. Awareness of sand flies based on the ability of respondents to identify the insects using up to seven predetermined characteristics was significantly greater among inhabitants of houses occupied by at least one Mn+ve individual. Five species of phlebotomine sand fly, including three suspected Leishmania vectors, were collected within plantations under three different cultivation systems. Four of these species i.e., Lu. fischeri (Pinto 1926), Lu. migonei (França 1920), Lu. misionensis (Castro 1959) and Lutzomyia whitmani (Antunes & Coutinho 1939) were collected in an organic plantation and the last of these was also present in the other two plantation types. The remaining species, Lu. intermedia (Lutz & Neiva 1912), was collected in plantations under both the "adensado" and "convencional" systems. The results of this study indicate that transmission of Leishmania to man in coffee-growing areas of Minas Gerais may involve phlebotomine sand flies that inhabit plantations.

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In most Western postindustrial societies today, the population is aging, businesses are faced with global integration, and important migration flows are taking place. Increasingly work organizations are hiring crossnational and multicultural workteams. In this situation it is important to understand the influence of certain individual and cultural characteristics on the process of professional integration. The present study explores the links between personality traits, demographic characteristics (age, sex, education, income, and nationality), work engagement, and job stress. The sample consisted of 618 participants, including 394 Swiss workers (200 women, 194 men) and 224 foreigners living and working in Switzerland (117 women, 107 men). Each participant completed the NEO-FFI, the UWES, and the GWSS questionnaires. Our results show an interaction between age and nationality with respect to work engagement and general job stress. The levels of work engagement and job stress appear to increase with age among national wotkers, whereas they decrease among foreign workers. In addition, work engagement was negatively associated with Neuroticism and positively with the other four personality dimensions. Finally, job stress was positively associated with Neuroticism and Conscientiousness, and negatively associated with Extraversion. However, the strength of these relationships appeared to vary according to the worker's nationality, age, sex, education, and income.

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The specific sensitization of tumor cells to the apoptotic response induced by genotoxins is a promising way of increasing the efficacy of chemotherapies. The RasGAP-derived fragment N2, while not regulating apoptosis in normal cells, potently sensitizes tumor cells to cisplatin- and other genotoxin-induced cell death. Here we show that fragment N2 in living cells is mainly located in the cytoplasm and only minimally associated with specific organelles. The cytoplasmic localization of fragment N2 was required for its cisplatin-sensitization property because targeting it to the mitochondria or the ER abrogated its ability to increase the death of tumor cells in response to cisplatin. These results indicate that fragment N2 requires a spatially constrained cellular location to exert its anti-cancer activity.

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Tropical cyclones are affected by a large number of climatic factors, which translates into complex patterns of occurrence. The variability of annual metrics of tropical-cyclone activity has been intensively studied, in particular since the sudden activation of the North Atlantic in the mid 1990’s. We provide first a swift overview on previous work by diverse authors about these annual metrics for the North-Atlantic basin, where the natural variability of the phenomenon, the existence of trends, the drawbacks of the records, and the influence of global warming have been the subject of interesting debates. Next, we present an alternative approach that does not focus on seasonal features but on the characteristics of single events [Corral et al., Nature Phys. 6, 693 (2010)]. It is argued that the individual-storm power dissipation index (PDI) constitutes a natural way to describe each event, and further, that the PDI statistics yields a robust law for the occurrence of tropical cyclones in terms of a power law. In this context, methods of fitting these distributions are discussed. As an important extension to this work we introduce a distribution function that models the whole range of the PDI density (excluding incompleteness effects at the smallest values), the gamma distribution, consisting in a powerlaw with an exponential decay at the tail. The characteristic scale of this decay, represented by the cutoff parameter, provides very valuable information on the finiteness size of the basin, via the largest values of the PDIs that the basin can sustain. We use the gamma fit to evaluate the influence of sea surface temperature (SST) on the occurrence of extreme PDI values, for which we find an increase around 50 % in the values of these basin-wide events for a 0.49 C SST average difference. Similar findings are observed for the effects of the positive phase of the Atlantic multidecadal oscillation and the number of hurricanes in a season on the PDI distribution. In the case of the El Niño Southern oscillation (ENSO), positive and negative values of the multivariate ENSO index do not have a significant effect on the PDI distribution; however, when only extreme values of the index are used, it is found that the presence of El Niño decreases the PDI of the most extreme hurricanes.

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Summary : Division of labour is one of the most fascinating aspects of social insects. The efficient allocation of individuals to a multitude of different tasks requires a dynamic adjustment in response to the demands of a changing environment. A considerable number of theoretical models have focussed on identifying the mechanisms allowing colonies to perform efficient task allocation. The large majority of these models are built on the observation that individuals in a colony vary in their propensity (response threshold) to perform different tasks. Since individuals with a low threshold for a given task stimulus are more likely to perform that task than individuals with a high threshold, infra-colony variation in individual thresholds results in colony division of labour. These theoretical models suggest that variation in individual thresholds is affected by the within-colony genetic diversity. However, the models have not considered the genetic architecture underlying the individual response thresholds. This is important because a better understanding of division of labour requires determining how genotypic variation relates to differences in infra-colony response threshold distributions. In this thesis, we investigated the combined influence on task allocation efficiency of both, the within-colony genetic variability (stemming from variation in the number of matings by queens) and the number of genes underlying the response thresholds. We used an agent-based simulator to model a situation where workers in a colony had to perform either a regulatory task (where the amount of a given food item in the colony had to be maintained within predefined bounds) or a foraging task (where the quantity of a second type of food item collected had to be the highest possible). The performance of colonies was a function of workers being able to perform both tasks efficiently. To study the effect of within-colony genetic diversity, we compared the performance of colonies with queens mated with varying number of males. On the other hand, the influence of genetic architecture was investigated by varying the number of loci underlying the response threshold of the foraging and regulatory tasks. Artificial evolution was used to evolve the allelic values underlying the tasks thresholds. The results revealed that multiple matings always translated into higher colony performance, whatever the number of loci encoding the thresholds of the regulatory and foraging tasks. However, the beneficial effect of additional matings was particularly important when the genetic architecture of queens comprised one or few genes for the foraging task's threshold. By contrast, higher number of genes encoding the foraging task reduced colony performance with the detrimental effect being stronger when queens had mated with several males. Finally, the number of genes determining the threshold for the regulatory task only had a minor but incremental effect on colony performance. Overall, our numerical experiments indicate the importance of considering the effects of queen mating frequency, genetic architecture underlying task thresholds and the type of task performed when investigating the factors regulating the efficiency of division of labour in social insects. In this thesis we also investigate the task allocation efficiency of response threshold models and compare them with neural networks. While response threshold models are widely used amongst theoretical biologists interested in division of labour in social insects, our simulation reveals that they perform poorly compared to a neural network model. A major shortcoming of response thresholds is that they fail at one of the most crucial requirement of division of labour, the ability of individuals in a colony to efficiently switch between tasks under varying environmental conditions. Moreover, the intrinsic properties of the threshold models are that they lead to a large proportion of idle workers. Our results highlight these limitations of the response threshold models and provide an adequate substitute. Altogether, the experiments presented in this thesis provide novel contributions to the understanding of how division of labour in social insects is influenced by queen mating frequency and genetic architecture underlying worker task thresholds. Moreover, the thesis also provides a novel model of the mechanisms underlying worker task allocation that maybe more generally applicable than the widely used response threshold models. Resumé : La répartition du travail est l'un des aspects les plus fascinants des insectes vivant en société. Une allocation efficace de la multitude de différentes tâches entre individus demande un ajustement dynamique afin de répondre aux exigences d'un environnement en constant changement. Un nombre considérable de modèles théoriques se sont attachés à identifier les mécanismes permettant aux colonies d'effectuer une allocation efficace des tâches. La grande majorité des ces modèles sont basés sur le constat que les individus d'une même colonie diffèrent dans leur propension (inclination à répondre) à effectuer différentes tâches. Etant donné que les individus possédant un faible seuil de réponse à un stimulus associé à une tâche donnée sont plus disposés à effectuer cette dernière que les individus possédant un seuil élevé, les différences de seuils parmi les individus vivant au sein d'une même colonie mènent à une certaine répartition du travail. Ces modèles théoriques suggèrent que la variation des seuils des individus est affectée par la diversité génétique propre à la colonie. Cependant, ces modèles ne considèrent pas la structure génétique qui est à la base des seuils de réponse individuels. Ceci est très important car une meilleure compréhension de la répartition du travail requière de déterminer de quelle manière les variations génotypiques sont associées aux différentes distributions de seuils de réponse à l'intérieur d'une même colonie. Dans le cadre de cette thèse, nous étudions l'influence combinée de la variabilité génétique d'une colonie (qui prend son origine dans la variation du nombre d'accouplements des reines) avec le nombre de gènes supportant les seuils de réponse, vis-à-vis de la performance de l'allocation des tâches. Nous avons utilisé un simulateur basé sur des agents pour modéliser une situation où les travailleurs d'une colonie devaient accomplir une tâche de régulation (1a quantité d'une nourriture donnée doit être maintenue à l'intérieur d'un certain intervalle) ou une tâche de recherche de nourriture (la quantité d'une certaine nourriture doit être accumulée autant que possible). Dans ce contexte, 'efficacité des colonies tient en partie des travailleurs qui sont capable d'effectuer les deux tâches de manière efficace. Pour étudier l'effet de la diversité génétique d'une colonie, nous comparons l'efficacité des colonies possédant des reines qui s'accouplent avec un nombre variant de mâles. D'autre part, l'influence de la structure génétique a été étudiée en variant le nombre de loci à la base du seuil de réponse des deux tâches de régulation et de recherche de nourriture. Une évolution artificielle a été réalisée pour évoluer les valeurs alléliques qui sont à l'origine de ces seuils de réponse. Les résultats ont révélé que de nombreux accouplements se traduisaient toujours en une plus grande performance de la colonie, quelque soit le nombre de loci encodant les seuils des tâches de régulation et de recherche de nourriture. Cependant, les effets bénéfiques d'accouplements additionnels ont été particulièrement important lorsque la structure génétique des reines comprenait un ou quelques gènes pour le seuil de réponse pour la tâche de recherche de nourriture. D'autre part, un nombre plus élevé de gènes encodant la tâche de recherche de nourriture a diminué la performance de la colonie avec un effet nuisible d'autant plus fort lorsque les reines s'accouplent avec plusieurs mâles. Finalement, le nombre de gènes déterminant le seuil pour la tâche de régulation eu seulement un effet mineur mais incrémental sur la performance de la colonie. Pour conclure, nos expériences numériques révèlent l'importance de considérer les effets associés à la fréquence d'accouplement des reines, à la structure génétique qui est à l'origine des seuils de réponse pour les tâches ainsi qu'au type de tâche effectué au moment d'étudier les facteurs qui régulent l'efficacité de la répartition du travail chez les insectes vivant en communauté. Dans cette thèse, nous étudions l'efficacité de l'allocation des tâches des modèles prenant en compte des seuils de réponses, et les comparons à des réseaux de neurones. Alors que les modèles basés sur des seuils de réponse sont couramment utilisés parmi les biologistes intéressés par la répartition des tâches chez les insectes vivant en société, notre simulation montre qu'ils se révèlent peu efficace comparé à un modèle faisant usage de réseaux de neurones. Un point faible majeur des seuils de réponse est qu'ils échouent sur un point crucial nécessaire à la répartition des tâches, la capacité des individus d'une colonie à commuter efficacement entre des tâches soumises à des conditions environnementales changeantes. De plus, les propriétés intrinsèques des modèles basés sur l'utilisation de seuils conduisent à de larges populations de travailleurs inactifs. Nos résultats mettent en évidence les limites de ces modèles basés sur l'utilisation de seuils et fournissent un substitut adéquat. Ensemble, les expériences présentées dans cette thèse fournissent de nouvelles contributions pour comprendre comment la répartition du travail chez les insectes vivant en société est influencée par la fréquence d'accouplements des reines ainsi que par la structure génétique qui est à l'origine, pour un travailleur, du seuil de réponse pour une tâche. De plus, cette thèse fournit également un nouveau modèle décrivant les mécanismes qui sont à l'origine de l'allocation des tâches entre travailleurs, mécanismes qui peuvent être appliqué de manière plus générale que ceux couramment utilisés et basés sur des seuils de réponse.