70 research outputs found

    A minimaj-preserving crystal on ordered multiset partitions

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    We provide a crystal structure on the set of ordered multiset partitions, which recently arose in the pursuit of the Delta Conjecture. This conjecture was stated by Haglund, Remmel and Wilson as a generalization of the Shuffle Conjecture. Various statistics on ordered multiset partitions arise in the combinatorial analysis of the Delta Conjecture, one of them being the minimaj statistic, which is a variant of the major index statistic on words. Our crystal has the property that the minimaj statistic is constant on connected components of the crystal. In particular, this yields another proof of the Schur positivity of the graded Frobenius series of the generalization Rn,kR_{n,k} due to Haglund, Rhoades and Shimozono of the coinvariant algebra RnR_n. The crystal structure also enables us to demonstrate the equidistributivity of the minimaj statistic with the major index statistic on ordered multiset partitions.Comment: 17 pages; v2 contains minor changes suggested by referee, references update

    PreocupaçÔes de carreira e adaptabilidade : estudo exploratĂłrio com uma amostra de candidatos a sargentos e oficiais do ExĂ©rcito PortuguĂȘs

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    Tese de mestrado, Psicologia (Psicologia dos Recursos Humanos, do Trabalho e das OrganizaçÔes), Universidade de Lisboa, Faculdade de Psicologia, 2010O presente trabalho consiste num estudo exploratĂłrio sobre as preocupaçÔes de carreira e as dimensĂ”es da adaptabilidade, baseando-se na Perspectiva de Desenvolvimento da Carreira de Donald Super e na Perspectiva Construtivista de Mark Savickas. Pretende-se, ainda, contribuir para a investigação acerca do InventĂĄrio sobre Adaptabilidade, que se encontra ainda em estudo no Ăąmbito de um Projecto Internacional. Foram aplicados o InventĂĄrio das PreocupaçÔes de Carreira e o InventĂĄrio sobre Adaptabilidade a uma amostra de 75 adultos candidatos a Sargentos e Oficiais do ExĂ©rcito PortuguĂȘs. Os resultados obtidos tendem a confirmar as hipĂłteses de investigação formuladas, apontando para a relação entre a variĂĄvel idade e as tarefas de desenvolvimento das fases da carreira Exploração e Estabelecimento, para a predominĂąncia das dimensĂ”es Confiança e Cooperação, e para a relação entre preocupaçÔes de carreira e dimensĂ”es da adaptabilidade. Apresentam-se as conclusĂ”es do presente estudo, algumas limitaçÔes deste e futuras linhas de investigação. Tecem-se tambĂ©m algumas consideraçÔes sobre as implicaçÔes do estudo para as prĂĄticas de gestĂŁo de carreira.This work is an exploratory study about the career concerns and the dimensions of adaptability, based on the Perspective of the Career Development of Donald Super and the Constructivist Perspective of Mark Savickas. It is also intended to contribute to the research on the Career Adapt-Abilities Inventory, which is still under investigation as part of an International Project. The Career Concerns Inventory and the Career Adapt-Abilities Inventory were applied to a sample of 75 adult candidates to Sergeants and Officers of the Portuguese Army. The results seem to confirm the research hypotheses, pointing to the relation between the variable age and the developmental tasks of the Exploration and Establishment career phases, to the predominance of the dimensions Cooperation, and Confidence and also to the relation between career concerns and adaptability dimensions. The findings of this study, some of its limitations and future research paths are presented. Some reflections are also discussed in what concerns the study's implications for the career management practices

    Quantifying energy expenditure in childhood: utility in managing pediatric metabolic disorders.

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    BACKGROUND: Energy expenditure prediction equations are used to estimate energy intake based on general population measures. However, when using equations to compare with a disease cohort with known metabolic abnormalities, it is important to derive one's own equations based on measurement conditions matching the disease cohort. OBJECTIVE: We aimed to use newly developed prediction equations based on a healthy pediatric population to describe and predict resting energy expenditure (REE) in a cohort of pediatric patients with thyroid disorders. METHODS: Body composition was measured by DXA and REE was assessed by indirect calorimetry in 201 healthy participants. A prediction equation for REE was derived in 100 healthy participants using multiple linear regression and z scores were calculated. The equation was validated in 101 healthy participants. This method was applied to participants with resistance to thyroid hormone (RTH) disorders, due to mutations in either thyroid hormone receptor ÎČ or α (ÎČ: female n = 17, male n = 9; α: female n = 1, male n = 1), with deviation of REE in patients compared with the healthy population presented by the difference in z scores. RESULTS: The prediction equation for REE = 0.061 * Lean soft tissue (kg) - 0.138 * Sex (0 male, 1 female) + 2.41 (R2 = 0.816). The mean ± SD of the residuals is -0.02 ± 0.44 kJ/min. Mean ± SD REE z scores for RTHÎČ patients are -0.02 ± 1.26. z Scores of -1.69 and -2.05 were recorded in male (n = 1) and female ( n = 1) RTHα patients. CONCLUSIONS: We have described methodology whereby differences in REE between patients with a metabolic disorder and healthy participants can be expressed as a z score. This approach also enables change in REE after a clinical intervention (e.g., thyroxine treatment of RTHα) to be monitored

    Long-term thermal sensitivity of Earth’s tropical forests

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    The sensitivity of tropical forest carbon to climate is a key uncertainty in predicting global climate change. Although short-term drying and warming are known to affect forests, it is unknown if such effects translate into long-term responses. Here, we analyze 590 permanent plots measured across the tropics to derive the equilibrium climate controls on forest carbon. Maximum temperature is the most important predictor of aboveground biomass (−9.1 megagrams of carbon per hectare per degree Celsius), primarily by reducing woody productivity, and has a greater impact per °C in the hottest forests (>32.2°C). Our results nevertheless reveal greater thermal resilience than observations of short-term variation imply. To realize the long-term climate adaptation potential of tropical forests requires both protecting them and stabilizing Earth’s climate

    Revealing the sequence and resulting cellular morphology of receptor-ligand interactions during plasmodium falciparum invasion of erythrocytes

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    During blood stage Plasmodium falciparum infection, merozoites invade uninfected erythrocytes via a complex, multistep process involving a series of distinct receptor-ligand binding events. Understanding each element in this process increases the potential to block the parasite's life cycle via drugs or vaccines. To investigate specific receptor-ligand interactions, they were systematically blocked using a combination of genetic deletion, enzymatic receptor cleavage and inhibition of binding via antibodies, peptides and small molecules, and the resulting temporal changes in invasion and morphological effects on erythrocytes were filmed using live cell imaging. Analysis of the videos have shown receptor-ligand interactions occur in the following sequence with the following cellular morphologies; 1) an early heparin-blockable interaction which weakly deforms the erythrocyte, 2) EBA and PfRh ligands which strongly deform the erythrocyte, a process dependant on the merozoite's actin-myosin motor, 3) a PfRh5-basigin binding step which results in a pore or opening between parasite and host through which it appears small molecules and possibly invasion components can flow and 4) an AMA1-RON2 interaction that mediates tight junction formation, which acts as an anchor point for internalization. In addition to enhancing general knowledge of apicomplexan biology, this work provides a rational basis to combine sequentially acting merozoite vaccine candidates in a single multi-receptor-blocking vaccine
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