Compensatory evolution and the origins of innovations

Cryptic genetic sequences have attenuated effects on phenotypes. In the classic view, relaxed selection allows cryptic genetic diversity to build up across individuals in a population, providing alleles that may later contribute to adaptation when co-opted - e.g. following a mutation increasing expression from a low, attenuated baseline. This view is described, for example, by the metaphor of the spread of a population across a neutral network in genotype space. As an alternative view, consider the fact that most phenotypic traits are affected by multiple sequences, including cryptic ones. Even in a strictly clonal population, the co-option of cryptic sequences at different loci may have different phenotypic effects and offer the population multiple adaptive possibilities. Here, we model the evolution of quantitative phenotypic characters encoded by cryptic sequences, and compare the relative contributions of genetic diversity and of variation across sites to the phenotypic potential of a population. We show that most of the phenotypic variation accessible through co-option would exist even in populations with no polymorphism. This is made possible by a history of compensatory evolution, whereby the phenotypic effect of a cryptic mutation at one site was balanced by mutations elsewhere in the genome, leading to a diversity of cryptic effect sizes across sites rather than across individuals. Cryptic sequences might accelerate adaptation and facilitate large phenotypic changes even in the absence of genetic diversity, as traditionally defined in terms of alternative alleles

The evolution of genetic architectures underlying quantitative traits

In the classic view introduced by R. A. Fisher, a quantitative trait is encoded by many loci with small, additive effects. Recent advances in QTL mapping have begun to elucidate the genetic architectures underlying vast numbers of phenotypes across diverse taxa, producing observations that sometimes contrast with Fisher's blueprint. Despite these considerable empirical efforts to map the genetic determinants of traits, it remains poorly understood how the genetic architecture of a trait should evolve, or how it depends on the selection pressures on the trait. Here we develop a simple, population-genetic model for the evolution of genetic architectures. Our model predicts that traits under moderate selection should be encoded by many loci with highly variable effects, whereas traits under either weak or strong selection should be encoded by relatively few loci. We compare these theoretical predictions to qualitative trends in the genetics of human traits, and to systematic data on the genetics of gene expression levels in yeast. Our analysis provides an evolutionary explanation for broad empirical patterns in the genetic basis of traits, and it introduces a single framework that unifies the diversity of observed genetic architectures, ranging from Mendelian to Fisherian.Comment: Minor changes in the text; Added supplementary materia

The biased evolution of generation time

Many life-history traits, like the age at maturity or adult longevity, are important determinants of the generation time. For instance, semelparous species whose adults reproduce once and die have shorter generation times than iteroparous species that reproduce on several occasions. A shorter generation time ensures a higher growth rate in stable environments where resources are in excess, and is therefore a positively selected feature in this (rarely met) situation. In a stable and limiting environment, all combination of traits (or strategies) that produce the same number of viable offspring on average are strictly neutral even when their generation times differ. We first study the evolution of life-history strategies with different generation times in this context, and show that those with the longest generation time represent the most likely evolutionary outcomes. Indeed, strategies with longer generation times generate fewer mutants per time unit, which makes them less likely to be replaced within a given time period. This `turnover bias' inevitably exists and favors the evolution of strategies with long generation times. Its real impact, however, should depend on the strength and direction of other evolutionary forces; selection for short generation times, for instance, may oppose turnover bias. Likewise, the evolutionary outcome depends on the strength of such selection and population size, comparably to other biases acting on the occurrence of mutations.Comment: Now we also study the evolution of development duration, suggesting that turnover bias is involved in the evolutionary dynamics of any trait linked with the generation tim

Demand Prediction and Inventory Management of Surgical Supplies

Effective supply chain management is critical to operations in various industries, including healthcare. Demand prediction and inventory management are essential parts of healthcare supply chain management for ensuring optimal patient outcomes, controlling costs, and minimizing waste. The advances in data analytics and technology have enabled many sophisticated approaches to demand forecasting and inventory control. This study aims to leverage these advancements to accurately predict demand and manage the inventory of surgical supplies to reduce costs and provide better services to patients. In order to achieve this objective, a Long Short-Term Memory (LSTM) model is developed to predict the demand for commonly used surgical supplies. Moreover, the volume of scheduled surgeries influences the demand for certain surgical supplies. Hence, another LSTM model is adopted from the literature to forecast surgical case volumes and predict the procedure-specific surgical supplies. A few new features are incorporated into the adopted model to account for the variations in the surgical case volumes caused by COVID-19 in 2020. This study then develops a multi-item capacitated dynamic lot-sizing replenishment model using Mixed Integer Programming (MIP). However, forecasting is always considered inaccurate, and demand is hardly deterministic in the real world. Therefore, a Two-Stage Stochastic Programming (TSSP) model is developed to address these issues. Experimental results demonstrate that the TSSP model provides an additional benefit of $2,328.304 over the MIP model

Demand Prediction and Inventory Management of Surgical Supplies

Effective supply chain management is critical to operations in various industries, including healthcare. Demand prediction and inventory management are essential parts of healthcare supply chain management for ensuring optimal patient outcomes, controlling costs, and minimizing waste. The advances in data analytics and technology have enabled many sophisticated approaches to demand forecasting and inventory control. This study aims to leverage these advancements to accurately predict demand and manage the inventory of surgical supplies to reduce costs and provide better services to patients. In order to achieve this objective, a Long Short-Term Memory (LSTM) model is developed to predict the demand for commonly used surgical supplies. Moreover, the volume of scheduled surgeries influences the demand for certain surgical supplies. Hence, another LSTM model is adopted from the literature to forecast surgical case volumes and predict the procedure-specific surgical supplies. A few new features are incorporated into the adopted model to account for the variations in the surgical case volumes caused by COVID-19 in 2020. This study then develops a multi-item capacitated dynamic lot-sizing replenishment model using Mixed Integer Programming (MIP). However, forecasting is always considered inaccurate, and demand is hardly deterministic in the real world. Therefore, a Two-Stage Stochastic Programming (TSSP) model is developed to address these issues. Experimental results demonstrate that the TSSP model provides an additional benefit of $2,328.304 over the MIP model

Computation of weighted capacity

AbstractWe introduce a method for computing the weighted capacity of a closed plane set. The method automatically yields upper and lower bounds for the capacity, and, for compact sets, these bounds converge to the true value of the capacity. No prior knowledge of the support of the equilibrium measure is required, and indeed the method can be used to determine this support. We discuss a number of examples in detail

Développer des habitudes en milieu de travail – une approche par la conception

RÉSUMÉ : Pour limiter les infections nosocomiales (les infections acquises à l’hôpital) il est recommandé aux professionnels de la santé de se laver les mains à certains moments clés. Or on constate que le taux de conformité à ces pratiques au Québec est en deçà des attentes ministérielles. Des interventions comportementales ont été développées face à ce problème, mais le peu de travaux faisant état de leur durabilité montre que les effets de l’intervention ont tendance à se dissiper au bout de six mois. Or la problé-matique de l’adoption de bonnes pratiques de prévention des infections est celle de l’adoption d’un comportement durable dans le temps. Il s’agit donc de changer une pratique de travail quotidienne, problématique que l’on retrouve lors de l’implantation d’un changement en organisation. Plus précisément, nous nous intéressons à concevoir une méthode pour accompagner le personnel de terrain afin qu’il conçoive des solutions lui permettant de développer des comportements pérennes en organisation. S’agissant de proposer un artéfact à utiliser en organisation, la méthodologie de recherche utilisée est celle des sciences de la conception. La solution proposée est la méthode FOCALE, acronyme pour Focaliser, Observer au travers de CREATE (acronyme de Cue – Reaction – Evaluation – Ability – Timing – Exécution, processus modélisant les étapes cognitives menant à la réalisation d’une action), Analyser, Libérer les idées, Expérimenter. Cette méthode fonctionne comme une méthode de résolution de problèmes, mais intègre des éléments liés au fonctionnement et au changement de comportement humain. La méthode FOCALE a été testée au sein du CIMAR-Lab de Polytechnique Montréal avec un total de huit participants. Pour cela, les participants ont effectué la méthode FOCALE puis ont répondu à un questionnaire. Ainsi, la méthode semble bien remplir ses fonctionnalités, mais les participants l’ont trouvée un peu complexe et ont suggéré de nombreuses voies d’amélioration, principalement en ce qui concerne la mise en œuvre de la méthode pour la rendre plus fonctionnelle. Cela ouvre la voie à de nouveaux travaux pour améliorer la méthode FOCALE, continuer à la tester dans différents environnements pour valider son efficience, et travailler à la prise en compte des éléments de fonctionnement et de changement du comportement humain dans la résolution de problèmes.----------ABSTRACT : In order to reduce hospital-acquired infections, the World Health Organization recommends that healthcare professionals wash their hands at some key moments. However the compliance rate of hand hygiene in Québec sets below the state’s expectations. To address this problem, behavioral interventions were developed by researchers. But few papers look into the sustainability (in time) of the outcome of the interventions. And some papers report that the effects of the intervention tend to disappear after six months. The issue of adopting good practices of infection prevention is indeed tied to the issue of adopting a long-lasting behavior. To improve hand hygiene rates, a work practice thus needs to be changed. Such an issue is also encountered when looking at implementing change in any organization. More precisely we got interested in designing a methodology to help workers design solutions themselves to enable them to develop sustainable behaviors in organization. To do that a design science research approach is used as the aim is to design an artefact (the method) that will be used in organizations. Thus the proposed solution is the FOCALE method. It’s an acronym that stands for Focus, Observe through CREATE (acronym for Cue – Reaction – Evaluation – Ability – Timing – Execution, it’s a process that shows the cognitive steps leading to taking action), Analyze, Let ideas flow, Experiment. This method embeds problem solving steps and principles linked to human behavior functioning and change. The FOCALE method was tested in the CIMAR-Lab at Polytechnique Montréal with eight participants. They used the method and answered a questionnaire. The results show that the method meets its desired functionalities but is a bit complex. Thus participants offered ways to improve it, especially regarding the implementation of the method. Therefore, further research could look into improving the FOCALE method or testing it in different environment settings to assess its efficiency. It could also be interesting to look into taking human behavior functioning and change principles more into consideration when looking at solving problems

Calcul de capacités

La capacité d'un ensemble est une notion qui, bien que très fortement motivée par la physique, intervient naturellement dans de très nombreuses branches de l'analyse mathématique, comme l'analyse complexe, la théorie du potentiel et des équations aux dérivées partielles ou dans l'approximation rationnelle. Cette thèse se concentre sur les capacités définies par des intégrales à noyaux. Le premier chapitre se veut un bref rappel des concepts fondamentaux en théorie du potentiel ainsi que des outils nécessaires pour la suite de cette thèse. Les deuxième et troisième chapitres de la thèse énoncent les principes des algorithmes de calcul de la capacité dans les cas généraux et pondérés respectivement et contiennent également des preuves rigoureuses de convergence desdits algorithmes. Le quatrième et dernier chapitre de la thèse énonce quelques versions modifiées des méthodes de calculs de la capacité et contient de nombreux exemples illustrés par des tableaux et des graphiques. On y remarque également que les moyens mis en oeuvre pour approximer la capacité permettent d'estimer le support et le potentiel à l'équilibre

The Cox’s Bazar Of Bangladesh - a rising tourist spot in the World: its economic prospects and constraints

Currently Cox’s Bazar of Bangladesh has been recognized as a rising tourists’ spot among the fastest growing destinations in the world. Presently it also holds first position in the competition of world’s new seven wonders. In this context, the main initiative of the present study is to focus on the performance of Bangladesh of tourism in general and in Cox’s Bazar as a major tourist spot of the country in particular. The study mainly examines potential tourism products of Cox’s Bazar and its nearer areas, performance of Bangladesh tourism and prevailing constraints and challenges of the same. The study results reveal that Bangladesh has huge prospects to flourish its economy through tourism and world recognized heritage ‘Cox’s Bazar’ has many tourism products to attract world-wide tourists’. But due to lack of resource constraints and other reasons government initiatives are not adequate to develop (specially infrastructure) tourism in the country and so, this industry still unexplored to most potential tourists’ of the world. The study concludes that both government and private interventions are vital one to develop and modernize the Cox’s Bazaar (tourist capital of the country) including other potential spots of Bangladesh