Social and temporal organization in an ant colony

Ant colonies are known for their complex and efficient social organization that com-pletely lacks hierarchical structure. However, due to methodological difficulties in follow¬ing all ants of a colony, it was until now impossible to investigate the social and temporal organization of colonies. We developed a tracking system that allows tracking the posi¬tions and orientations of several hundred individually labeled ants continuously, providing for the first time quantitative long term data on all individuals of a colony. These data permit reconstructing trajectories, activity patterns and social networks of all ants in a colony and enable us to investigate ant behavior quantitatively in previously unpreceded ways. By analyzing the spatial positions and social interactions of all ants in six colonies for 41 days we show that ant colonies are organized in groups of nurses, nest patrollers and foragers. Workers of each group were highly interconnected and occupied similar spa¬tial locations in the nest. Groups strongly segregated spatially, and were characterized by unique behavioral signatures. Nurses spent most of their time on the brood. Nest patrollers frequently visited the rubbish pile, and foragers frequently visited the forag¬ing arena. In addition nurses were on average younger than nest patrollers who were, in turn, younger than foragers. We further show that workers had a preferred behav¬ioral trajectory and moved from nursing to nest patrolling, and from nest patrolling to foraging. By analyzing the activity patterns of all ants we show that only a third of all workers in a colony exhibit circadian rhythms and that these rhythms shortened by on av¬erage 42 minutes in constant darkness, thereby demonstrating the presence of a functional endogenous clock. Most rhythmic workers were foragers suggesting that rhythmicity is tightly associated with task. Nurses and nest patrollers were arrhythmic which most likely reflects plasticity of the circadian clock, as isolated workers in many species exhibit circadian rhythmicity. Altogether our results emphasize that ant colonies, despite their chaotic appearance, repose on a strong underlying social and temporal organization. - Les colonies de fourmis sont connues pour leur organisation sociale complexe et effi-cace, charactérisée par un manque absolu de structure hiérarchique. Cependant, puisqu'il est techniquement très difficile de suivre toutes les fourmis d'une colonie, il a été jusqu'à maintenant impossible d'étudier l'organisation sociale et temporelle des colonies de four-mis. Nous avons développé un système qui permet d'extraire en temps réel à partir d'images vidéo les positions et orientations de plusieurs centaines de fourmis marquées individuellement. Nous avons pu ainsi générer pour la première fois des données quanti-tatives et longitudinales relatives à des fourmis appartenant à une colonie. Ces données nous ont permis de reconstruire la trajectoire et l'activité de chaque fourmi ainsi que ses réseaux sociaux. Ceci nous a permis d'étudier de manière exhaustive et objective le com-portement de tous les individus d'une colonie. En analysant les données spatiales et les interactions sociales de toutes les fourmis de six colonies qui ont été filmées pendant 41 jours, nous montrons que les fourmis d'une même colonie se répartissent en trois groupes: nourrices, patrouilleuses et approvisionneuses. Les fourmis d'un même groupe interagis-sent fréquemment et occupent le même espace à l'intérieur du nid. L'espace propre à un groupe se recoupe très peu avec celui des autres. Chaque groupe est caractérisé par un comportement typique. Les nourrices s'affairent surtout autour du couvain. Les pa-trouilleuses font de fréquents déplacements vers le tas d'ordures, et les approvisionneuses sortent souvent du nid. Les nourrices sont en moyenne plus jeunes que les patrouilleuses qui, à leur tour, sont plus jeunes que les approvisionneuses. De plus, nous montrons que les ouvrières changent de tâche au cours de leur vie, passant de nourrice à patrouilleuse puis à approvisionneuse. En analysant l'activité de chaque fourmi, nous montrons que seulement un tiers des ouvrières d'une colonie présente des rythmes circadiens et que ces rythmes diminuent en moyenne de 42 minutes lorsqu'il y a obscurité constante, ce qui démontre ainsi la présence d'une horloge endogène. De plus, la plupart des approvi¬sionneuses ont une activité rythmique alors que les nourrices et patrouilleuses présentent une activité arythmique, ce qui suggère que la rythmicité est étroitement associée à la tâche. L'arythmie des nourrices et patrouilleuses repose probablement sur une plasticité de l'horloge endogène car des ouvrières de nombreuses espèces font preuve d'une ryth¬micité circadienne lorsqu'elles sont isolées de la colonie. Dans l'ensemble nos résultats révèlent qu'une colonie de fourmis se fonde sur une solide organisation sociale et tem¬porelle malgré son apparence chaotique.

Ulnar nerve transposition at the elbow : local anesthesia should be preferred to general anesthesia

Après la compression du nerf médian au niveau du tunnel carpien, la compression du nerf ulnaire au niveau du coude est le deuxième syndrome compressif le plus fréquent des nerfs périphériques. La chirurgie des nerfs périphériques consiste dans une décompression nerveuse et est caractérisée par un suivi post¬opératoire parfois très douloureux avec des douleurs qui peuvent chroniciser si insuffisamment traitées. Le traitement chirurgical de décompression nerveuse se fait traditionnellement sous anesthésie générale ou régionale. Une analgésie post-opératoire plus efficace et durable avec moindre risque de chronicisation avait justifié ce choix jusqu'à ce jour. Grâce au développement de la chirurgie ambulatoire ces dernières années, un grand nombre d'interventions chirurgicales au niveau de la main sont effectués sous anesthésie locale. Au vu d'une meilleure connaissance de cette technique d'anesthésie, son rôle dans la chirurgie des nerfs périphériques a été remis en question. Alors que plusieurs études ont démontré que l'anesthésie locale est aussi efficace que l'anesthésie générale et régionale au sujet de la chirurgie du tunnel carpien, son utilisation pour la chirurgie du nerf ulnaire reste peu connue. La raison de l'hésitation à l'utilisation de l'anesthésie locale pour le traitement du tunnel ulnaire est due au fait que dans plus de la moitié des cas, une simple décompression n'est pas suffisante et qu'il est souvent nécessaire de transposer le nerf ulnaire devant l'épicondyle ulnaire. La seule publication disponible au sujet de l'utilisation de l'anesthésie locale dans le traitement du tunnel ulnaire considère comme irréalisable d'utiliser cette méthode dans le cas d'une transposition. Malgré cette mise en garde, nous avons, depuis plusieurs années, des excellents résultats avec la transposition du nerf ulnaire sous anesthésie locale. Avec le but d'objectiver notre expérience dans ce domaine nous avons souhaité analyser nos résultats de façon rétrospective avec particulière attention aux douleurs post-opératoires et à la satisfaction des patients. Les dossiers de cinquante patients Consécutifs (26F, 24M) opérés par le même chirurgien dans notre service de 2002 à 2012 ont été analysés rétrospectivement. Les critères suivants ont été récoltés: l'âge du patient, la profession, la main dominante, les détails des techniques opératoires utilisées, le type d'anesthésie, l'intensité du suivi ainsi que les complications, le niveau de douleur dans l'immédiat post-opératorie ainsi que à une année de l'intervention. Les patients ont été divisés en 4 groupes: les opérés sous anesthésie générale avec transposition du nerf (n=17) ou sans transposition (n=10) et les opérés sous anesthésie locale avec transposition (n=12) ou sans transposition (n=11). Au premier jour la douleur était comparable dans tous les groupes. A une semaine, elle était deux fois plus importante lorsque la transposition avait été réalisée sous anesthésie générale par rapport à si une anesthésie locale avait été effectuée (p=0.03). La satisfaction s'est révélée plus élevée mais non significative chez les patients opérés sous anesthésie locale. Ces derniers étaient significativement plus enclins à répéter la chirurgie comparé a ceux opérés sous anesthésie générale (p=0.04). En conclusion, les résultats de cette étude suggèrent que l'anesthésie locale est au moins autant efficace que l'anesthésie générale en termes de complications et de douleurs post-opératoires indépendamment du fait qu'une transposition nerveuse soit effectuée ou pas. Un meilleur contrôle des douleurs à une semaine post-opératoire a contribué à une haute satisfaction des patients de notre étude.

Iowa Medicaid Pharmaceutical and Therapeutics Committee and Diabetes Treatment Preferred Drug List, December 16, 2008

This document was produced to help the state and citizens of Iowa with the price list of preferred drug list of medicines that diabetics can use.

Free-breathing 3D coronary MRA: the impact of "isotropic" image resolution.

During conventional x-ray coronary angiography, multiple projections of the coronary arteries are acquired to define coronary anatomy precisely. Due to time constraints, coronary magnetic resonance angiography (MRA) usually provides only one or two views of the major coronary vessels. A coronary MRA approach that allowed for reconstruction of arbitrary isotropic orientations might therefore be desirable. The purpose of the study was to develop a three-dimensional (3D) coronary MRA technique with isotropic image resolution in a relatively short scanning time that allows for reconstruction of arbitrary views of the coronary arteries without constraints given by anisotropic voxel size. Eight healthy adult subjects were examined using a real-time navigator-gated and corrected free-breathing interleaved echoplanar (TFE-EPI) 3D-MRA sequence. Two 3D datasets were acquired for the left and right coronary systems in each subject, one with anisotropic (1.0 x 1.5 x 3.0 mm, 10 slices) and one with "near" isotropic (1.0 x 1.5 x 1.0 mm, 30 slices) image resolution. All other imaging parameters were maintained. In all cases, the entire left main (LM) and extensive portions of the left anterior descending (LAD) and the right coronary artery (RCA) were visualized. Objective assessment of coronary vessel sharpness was similar (41% +/- 5% vs. 42% +/- 5%; P = NS) between in-plane and through-plane views with "isotropic" voxel size but differed (32% +/- 7% vs. 23% +/- 4%; P < 0.001) with nonisotropic voxel size. In reconstructed views oriented in the through-plane direction, the vessel border was 86% more defined (P < 0.01) for isotropic compared with anisotropic images. A smaller (30%; P < 0.001) improvement was seen for in-plane reconstructions. Vessel diameter measurements were view independent (2.81 +/- 0.45 mm vs. 2.66 +/- 0.52 mm; P = NS) for isotropic, but differed (2.71 +/- 0.51 mm vs. 3.30 +/- 0.38 mm; P < 0.001) between anisotropic views. Average scanning time was 2:31 +/- 0:57 minutes for anisotropic and 7:11 +/- 3:02 minutes for isotropic image resolution (P < 0.001). We present a new approach for "near" isotropic 3D coronary artery imaging, which allows for reconstruction of arbitrary views of the coronary arteries. The good delineation of the coronary arteries in all views suggests that isotropic 3D coronary MRA might be a preferred technique for the assessment of coronary disease, although at the expense of prolonged scan times. Comparative studies with conventional x-ray angiography are needed to investigate the clinical utility of the isotropic strategy.

Keeping the Vermin Out: Perceived Disease Threat and Ideological Orientations as Predictors of Exclusionary Immigration Attitudes

Integrating evolutionary and social representations theories, the current study examines the relationship between perceived disease threat and exclusionary immigration attitudes in the context of a potential avian influenza pandemic. This large-scale disease provides a realistic context for investigating the link between disease threat and immigration attitudes. The main aim of this cross-sectional study (N=412) was to explore mechanisms through which perceived chronic and contextual disease threats operate on immigration attitudes. Structural equation models show that the relationship between chronic disease threat (germ aversion) and exclusionary immigration attitudes (assimiliationist immigration criteria, health-based immigration criteria and desire to reduce the proportion of foreigners) was mediated by ideological and normative beliefs (social dominance orientation, belief in a dangerous world), but not by contextual disease threat (appraisal of avian influenza pandemic threat). Contextual disease threat only predicted support for health-based immigration criteria. The conditions under which real-life disease threats influence intergroup attitudes are scrutinized. Convergence and dissimilarity of evolutionary and social representational approaches in accounting for the link between disease threat and immigration attitudes are discussed.

Identifying the preferred subset of enzymatic profiles in nonlinear kinetic metabolic models via multiobjective global optimization and pareto filters

Optimization models in metabolic engineering and systems biology focus typically on optimizing a unique criterion, usually the synthesis rate of a metabolite of interest or the rate of growth. Connectivity and non-linear regulatory effects, however, make it necessary to consider multiple objectives in order to identify useful strategies that balance out different metabolic issues. This is a fundamental aspect, as optimization of maximum yield in a given condition may involve unrealistic values in other key processes. Due to the difficulties associated with detailed non-linear models, analysis using stoichiometric descriptions and linear optimization methods have become rather popular in systems biology. However, despite being useful, these approaches fail in capturing the intrinsic nonlinear nature of the underlying metabolic systems and the regulatory signals involved. Targeting more complex biological systems requires the application of global optimization methods to non-linear representations. In this work we address the multi-objective global optimization of metabolic networks that are described by a special class of models based on the power-law formalism: the generalized mass action (GMA) representation. Our goal is to develop global optimization methods capable of efficiently dealing with several biological criteria simultaneously. In order to overcome the numerical difficulties of dealing with multiple criteria in the optimization, we propose a heuristic approach based on the epsilon constraint method that reduces the computational burden of generating a set of Pareto optimal alternatives, each achieving a unique combination of objectives values. To facilitate the post-optimal analysis of these solutions and narrow down their number prior to being tested in the laboratory, we explore the use of Pareto filters that identify the preferred subset of enzymatic profiles. We demonstrate the usefulness of our approach by means of a case study that optimizes the ethanol production in the fermentation of Saccharomyces cerevisiae.

Preferred Spatial Frequencies for Human Face Processing Are Associated with Optimal Class Discrimination in the Machine

Psychophysical studies suggest that humans preferentially use a narrow band of low spatial frequencies for face recognition. Here we asked whether artificial face recognition systems have an improved recognition performance at the same spatial frequencies as humans. To this end, we estimated recognition performance over a large database of face images by computing three discriminability measures: Fisher Linear Discriminant Analysis, Non-Parametric Discriminant Analysis, and Mutual Information. In order to address frequency dependence, discriminabilities were measured as a function of (filtered) image size. All three measures revealed a maximum at the same image sizes, where the spatial frequency content corresponds to the psychophysical found frequencies. Our results therefore support the notion that the critical band of spatial frequencies for face recognition in humans and machines follows from inherent properties of face images, and that the use of these frequencies is associated with optimal face recognition performance.

Most and Least Preferred Colours Differ According to Object Context : New Insights from an Unrestricted Colour Range

Humans like some colours and dislike others, but which particular colours and why remains to be understood. Empirical studies on colour preferences generally targeted most preferred colours, but rarely least preferred (disliked) colours. In addition, findings are often based on general colour preferences leaving open the question whether results generalise to specific objects. Here, 88 participants selected the colours they preferred most and least for three context conditions (general, interior walls, t-shirt) using a high-precision colour picker. Participants also indicated whether they associated their colour choice to a valenced object or concept. The chosen colours varied widely between individuals and contexts and so did the reasons for their choices. Consistent patterns also emerged, as most preferred colours in general were more chromatic, while for walls they were lighter and for t-shirts they were darker and less chromatic compared to least preferred colours. This meant that general colour preferences could not explain object specific colour preferences. Measures of the selection process further revealed that, compared to most preferred colours, least preferred colours were chosen more quickly and were less often linked to valenced objects or concepts. The high intra- and inter-individual variability in this and previous reports furthers our understanding that colour preferences are determined by subjective experiences and that most and least preferred colours are not processed equally.

Preferred Offer as a Method in Competitive Bidding

The objective of this master’s thesis was to find means and measures by which an industrial manufacturing company could find cost-competitive solutions in a price-driven market situation. Initially, it was essential to find individual high customer value spots from the offering. The study addressed this in an innovative way by providing the desired information for the entire range of offering. The research was carried out using the constructivist approach method. Firstly, the project and solution marketing literature was reviewed in order to establish an overview of the processes and strategies involved. This information was then used in conjunction with the company’s specific offering data to conduct a construction. This construction can be used in various functions within the target company to streamline and optimize the specifications into so-called “preferred offers”. The study also presents channels and methods with which to exploit the construction in practice in the target company. The study aimed to bring concrete improvements in competitiveness and profitability. One result of this study was the creation of a training material for internal use. This material is now used in several countries to inform and present to the staff the cost-competitive aspects of the target company’s offering.

Actual and perceived coaches' sportspersonship behaviours and their relationship with young athletes' sportspersonship orientations

Hom' s (2008) model of coaching effectiveness provides a framework that outlines the antecedent factors that influence coaches' behaviours as well as the way in which coaches' behaviours can influence the psychosocial development of athletes. Perceived coaches" behaviours have been shown to predict the self-reported unsportspersonlike behaviours of young athletes (Shields et aI., 2007). However, very few studies have examined actual coaches' sportspersonship behaviours (Arthur-Banning et aI., 2009; Cote et aI., 1993; Trudel e t aI., 1991). The purpose of this exploratory study was to investigate the relationships between coaches' and athletes' sportspersonship orientations and behaviours. Participants included competitive male basketball coaches (N = 5) and their male athletes aged 10 to 13 (N= 48). Two investigators systematically observed coaches' sportspersonship behaviours. Subsequently, coaches and athletes completed questionnaires based on the Multidimensional Sportspersonship Orientations Scale (MSOS; Vallerand et aI., 1997). The results showed that coaches' self-reported sportspersonship orientations and athletes' perceptions of their coaches behaviours were consistent with coaches' actual behaviours for respect for the rules and officials as well as for social conventions. A series of multiple regressions were conducted in order to determine whether or not athletes' perceptions of their coaches' sportspersonship behaviours predicted the sportspersonship orientations of athletes. The only significant regression model was for athletes' negative approach toward sport participation. The results also suggest that the MSOS has reliability and validity issues.

Certificate for Two Shares of Preferred Capital Stock in Gove Motor Car Company, Detroit, Michigan

Certificate for 2 shares of preferred capital stock in Gove Motor Car Company, Detroit, Michigan to Hamilton K. Woodruff, June 13, 1921.