826 resultados para longitudinal Poisson data
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The designing of effective intervention tools to improve immigrants’ labor market integration remains an important topic in contemporary Western societies. This study examines whether and how a new intervention tool, Working Life Certificate (WLC), helps unemployed immigrants to find employment and strengthen their belief of their vocational skills. The study is based on quantitative longitudinal survey data from 174 unemployed immigrants of various origins who participated in the pilot phase of WLC examinations in 2009. Surveys were administered in three waves: before the test, right after it, and three months later. Although it is often argued that the unemployment among immigrants is due either to their lack of skills and cultural differences or to discrimination in recruitment, scholars within social psychology of behavior change argue that the best way of helping people to achieve their goals (e.g. finding employment) is to build up their sense of self-efficacy, alter their outcome expectances in a more positive direction or to help them to construct more detailed action and coping plans. This study aims to shed light on the role of these concepts in immigrants’ labor market integration. The results support the theories of behavior change moderately. Having positive expectances regarding the outcomes of various job search behaviors was found to predict employment in the future. Together with action and coping planning it also predicted increase in job search behavior. The intervention, WLC, was able to affect participants’ self-efficacy, but contrary to expectations, self-efficacy was found not to be related to either job search behavior or future labor market status. Also, perceived discrimination did not explain problems in finding employment, but hints of subtle or structural discrimination were found. Adoption of Finnish work culture together with strong family culture was found to predict future employment. Hence, in this thesis I argue that awarding people diplomas should be preferred in immigrant integration training as it strengthens people’s sense of self-efficacy. Instead of teaching new information, more attention should be directed at changing people’s outcome expectances in a more positive direction and helping them to construct detailed plans on how to achieve their goals.
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The Richardson-Lucy algorithm is one of the most important algorithms in the image deconvolution area. However, one of its drawbacks is slow convergence. A very significant acceleration is obtained by the technique proposed by Biggs and Andrews (BA), which is implemented in the deconvlucy function of the Image Processing MATLAB toolbox. The BA method was developed heuristically with no proof of convergence. In this paper, we introduce the Heavy-Ball (H-B) method for Poisson data optimization and extend it to a scaled H-B method, which includes the BA method as a special case. The method has proof of the convergence rate of O(k-2), where k is the number of iterations. We demonstrate the superior convergence performance of the scaled H-B method on both synthetic and real 3D images.
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This article investigates to what extent the worldwide increase in body mass index (BMI) has been affected by economic globalization and inequality. We used time-series and longitudinal cross-national analysis of 127 countries from 1980 to 2008. Data on mean adult BMI were obtained from the Global Burden of Metabolic Risk Factors of Chronic Diseases Collaborating Group. Globalization was measured using the Swiss Economic Institute (KOF) index of economic globalization. Economic inequality between countries was measured with the mean difference in gross domestic product per capita purchasing power parity in international dollars. Economic inequality within countries was measured using the Gini index from the Standardized World Income Inequality Database. Other covariates including poverty, population size, urban population, openness to trade and foreign direct investment were taken from the World Development Indicators (WDI) database. Time-series regression analyses showed that the global increase in BMI is positively associated with both the index of economic globalization and inequality between countries, after adjustment for covariates. Longitudinal panel data analyses showed that the association between economic globalization and BMI is robust after controlling for all covariates and using different estimators. The association between economic inequality within countries and BMI, however, was significant only among high-income nations. More research is needed to study the pathways between economic globalization and BMI. These findings, however, contribute to explaining how contemporary globalization can be reformed to promote better health and control the global obesity epidemic. © 2013 Copyright Taylor and Francis Group, LLC.
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Increased understanding of knowledge transfer (KT) from universities to the wider regional knowledge ecosystem offers opportunities for increased regional innovation and commercialisation. The aim of this article is to improve the understanding of the KT phenomena in an open innovation context where multiple diverse quadruple helix stakeholders are interacting. An absorptive capacity-based conceptual framework is proposed, using a priori constructs which portrays the multidimensional process of KT between universities and its constituent stakeholders in pursuit of open innovation and commercialisation. Given the lack of overarching theory in the field, an exploratory, inductive theory building methodology was adopted using semi-structured interviews, document analysis and longitudinal observation data over a three-year period. The findings identify five factors, namely human centric factors, organisational factors, knowledge characteristics, power relationships and network characteristics, which mediate both the ability of stakeholders to engage in KT and the effectiveness of knowledge acquisition, assimilation, transformation and exploitation. This research has implications for policy makers and practitioners by identifying the need to implement interventions to overcome the barriers to KT effectiveness between regional quadruple helix stakeholders within an open innovation ecosystem.
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The Richardson–Lucy algorithm is one of the most important in image deconvolution. However, a drawback is its slow convergence. A significant acceleration was obtained using the technique proposed by Biggs and Andrews (BA), which is implemented in the deconvlucy function of the image processing MATLAB toolbox. The BA method was developed heuristically with no proof of convergence. In this paper, we introduce the heavy-ball (H-B) method for Poisson data optimization and extend it to a scaled H-B method, which includes the BA method as a special case. The method has a proof of the convergence rateof O(K^2), where k is the number of iterations. We demonstrate the superior convergence performance, by a speedup factor off ive, of the scaled H-B method on both synthetic and real 3D images.
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Thesis (Ph.D.)--University of Washington, 2012
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Les milieux de travail canadiens présentent des visages diversifiés et en pleine mutation. En raison de facteurs tels que les nouvelles technologies, la mondialisation, l’économie du savoir ou encore l’évolution démographique, la transformation des entreprises canadiennes passe par une main-d’œuvre qualifiée, adaptable et de qualité. Notre recherche s’inscrit dans le cadre des études s’intéressant aux comportements des entreprises en matière d’investissement en capital humain au Canada. Nous avons retenu un cadre théorique qui est constitué principalement de la théorie du capital humain, de celle des ressources internes et de l’approche des coûts et des bénéfices. Pour les fins de notre recherche, nous retenons une approche quantitative longitudinale, en utilisant des données secondaires issues du questionnaire des employeurs de l’Enquête sur le milieu de travail et les employés pour les années 1999 à 2005 inclusivement. La nature longitudinale de l’EMTE permet de corriger pour les biais liés à l’hétérogénéité non observée des firmes et à l’endogénéité possible de la variable de formation. Notre étude se divise globalement en trois articles. Dans les deux premiers cas, les dépenses en formation sont considérées comme une variable explicative de la productivité et du taux de roulement des employés. Dans le troisième cas, les dépenses de formation constituent la variable dépendante à l’étude. Le premier article examine l’effet des investissements en formation sur la productivité des entreprises canadiennes. La littérature scientifique traitant de l’impact de la formation sur la performance des entreprises continue de s’accroître dû aux nouvelles techniques d’estimations, à la disponibilité des données, et à l’intérêt grandissant pour le capital humain. Les résultats partiels des études antérieures montrent la possibilité que les retours des investissements réalisés en formation puissent avoir des effets au-delà de l’année courante. Sur le plan théorique, cette hypothèse a du sens, mais au niveau empirique il semble que les liens formels entre la formation et la productivité des entreprises ne sont pas clairement identifiés. Nos résultats montrent que les investissements en formation réalisés avec trois années de retard engendrent des effets positifs et significatifs sur la productivité à court et à moyen termes. L’interaction entre les différents types d’investissements permet de vérifier l’hypothèse à l’effet que les investissements en capital physique et en capital humain soient complémentaires et se supportent mutuellement. Après avoir procédé à l’estimation de l’effet des dépenses en formation structurée sur la productivité des entreprises, nous nous demandons pour quelles raisons les employeurs demeurent réticents quant aux retours des investissements en formation ? Dans le cadre de cette seconde réflexion, nous nous intéressons à deux dimensions de l’estimation du roulement, à savoir le roulement de nature volontaire et une mesure de l’optimum. Les résultats obtenus quant à l’effet des dépenses en formation structurée par employé sur les taux de roulement volontaire et optimal montrent que la relation est positive dans les deux cas. Cet article vise également à vérifier si différents outils organisationnels associés aux relations industrielles peuvent avoir un effet sur la réduction du taux de roulement volontaire des employés. Nos résultats montrent aussi que la présence syndicale et la perception d’un bon climat de travail traduisent dans un sens, un environnement dans lequel l’employeur et les employés ont des intérêts communs pour la poursuite de mêmes objectifs. Dans le cadre du troisième article, nous examinons certains déterminants des investissements en formation structurée au sein des milieux de travail. Nos résultats montrent qu’une entreprise de grande taille, qui investit davantage en capital physique par employé par rapport à la moyenne, au sein de laquelle un grand pourcentage de travailleurs utilisent un ordinateur, où il y a une proportion élevée de nouvelles embauches et pour laquelle l’employeur introduit un système cohérent de pratiques dépense davantage en formation structurée qu’une entreprise qui ne possède pas ces caractéristiques, toutes choses égales par ailleurs. Ces résultats permettent de discuter également de la complémentarité des facteurs faisant partie d’un cercle vertueux de croissance des entreprises pouvant déterminer les investissements en formation.
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L’Éducation Pour Tous mobilise la communauté internationale et les gouvernements depuis 1990. Cet engagement global renouvelé en 2000 sous l’auspice de l’UNESCO puis des Nations-Unies, porte notamment sur un objectif de base : l’universalisation de la scolarisation primaire complète pour tous les enfants d’âge scolaire à l’horizon de 2015. Plusieurs études sur la réalisation de cet objectif montrent que les pays en développement sont les plus à risque et que les progrès accomplis dans la plupart de ces pays, pourraient être plus importants si la pratique du redoublement faisait davantage l’objet de régulation et de contrôle. Cela contribuerait à améliorer la réussite scolaire et accroître la rétention des élèves au sein des systèmes éducatifs. La pratique du redoublement est en effet une tradition dans plusieurs systèmes éducatifs. Elle est particulièrement prépondérante dans certains groupes de pays ou régions, notamment en Afrique francophone au sud du Sahara. Dans ces pays, le PASEC - Programme d’Analyse des Systèmes Éducatifs de la CONFEMEN (Conférence des Ministres de l’Éducation Nationale des pays ayant le français en partage) - œuvre à améliorer l’accès à une éducation de qualité pour tous, par exemple, en informant les politiques sur la situation nationale du redoublement. Cette recherche sur le redoublement, la réussite scolaire et l’objectif de la Scolarisation Primaire Universelle (SPU) privilégie la dimension pédagogique, l’analyse empirique et étudie le cas du Sénégal. Elle présente et discute les indicateurs internationaux de suivi de l’objectif de la SPU, fait le point de l’état des connaissances sur le redoublement et la réussite scolaire et montre le défi que représente la réalisation de l’objectif de la SPU notamment dans les pays francophones d’Afrique sub-Saharienne. Exploitant les données existantes de l’enquête longitudinale de suivi de cohorte du PASEC au Sénégal entre 1995 et 2000, cette recherche examine le parcours scolaire des élèves en vue de la réalisation de l’objectif de la SPU. L’examen effectué combine des approches d’analyse transversale et longitudinale du redoublement et des apprentissages par rapport aux caractéristiques personnelles, familiales et scolaires de l’élève. Les résultats d’analyse montrent des variabilités, notamment par rapport aux caractéristiques personnelles de l’élève et à celles de sa classe et de son milieu de scolarisation. L’analyse longitudinale du redoublement s’est appuyée sur le diagramme de flux scolaire et a permis de produire un ensemble d’indicateurs d’efficacité interne du système éducatif du Sénégal. Pour la cohorte étudiée, du fait de l’importance des redoublements et des abandons scolaires, il faut en moyenne 9,4 années de scolarité pour que l’élève progresse du deuxième au sixième (dernier) grade du primaire. Seulement 39% de l’effectif de la cohorte survivent au dernier grade ce qui suggère que si cette tendance se maintenait, le Sénégal serait à risque de ne pas réaliser l’objectif de la SPU. Une évaluation de la situation courante à partir de données plus récentes serait requise. Le diagramme de flux scolaire constitue un outil de planification de l’éducation et représente de ce fait un important levier aux mains des autorités politiques pour agir sur les paramètres du système éducatif (paramètres liés à la qualité de l’éducation, à l’efficacité interne, etc.) afin de répondre à des objectifs spécifiques ou d’étapes pouvant conduire, par exemple, à la réalisation de l’objectif de la SPU.
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A partir de un levantamiento longitudinal de información (1956-2008) sobre las publicaciones seriadas de psicología en Colombia se identifican una serie de variaciones en diversas características editoriales de éstas que a su vez se relacionan con reconfiguraciones del entramado institucional y de política pública en el que se desenvuelve la publicación local en psicología. En su conjunto, esta contribución argumenta que el aumento evidente de la productividad de la psicología nacional ha sido el resultado de este conjunto de transformaciones tanto del contexto social como de la revista concebida como producto editorial, como objeto técnico.
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There is under-representation of senior female managers within small construction firms in the United Kingdom. The position is denying the sector a valuable pool of labour to address acute knowledge and skill shortages. Grounded theory on the career progression of senior female managers in these firms is developed from biographical interviews. First, a turning point model which distinguishes the interplay between human agency and work/home structure is given. Second, four career development phases are identified. The career journeys are characterized by ad hoc decisions and opportunities which were not influenced by external policies aimed at improving the representation of women in construction. Third, the 'hidden', but potentially significant, contribution of women-owned small construction firms is noted. The key challenge for policy and practice is to balance these external approaches with recognition of the 'inside out' reality of the 'lived experiences' of female managers. To progress this agenda there is a need for: appropriate longitudinal statistical data to quantify the scale of senior female managers and owners of small construction firms over time; and, social construction and gendered organizational analysis research to develop a general discourse on gender difference with these firms.
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he construction market around the world has witnessed the growing eminence of construction professional services (CPSs), such as urban planning, architecture, engineering, and consultancy, while the traditional contracting sector remains strong. Nowadays, it is not uncommon to see a design firm taking over the work of a traditional main contractor, or vice versa, of overseeing the delivery of a project. Although the two sectors of contracting and CPS share the same purpose of materializing the built environment, they are as different as they are interrelated. Much has been mentioned about the nexus between the two but little has been done to articulate it using empirical evidence. This study examined the nexus between contracting and CPS businesses by offering and testing lead-lag effects between the two sectors in the international market. A longitudinal panel data composed of 23 top international contractors and CPS firms was adopted. Surprisingly, results of the panel data analyses show that CPS business does not have a significant positive causal effect on contracting as a downstream business, and vice versa. CPS and contracting subsidiaries, although within the same company, do not necessarily form a consortium to undertake the same project; rather, they often collaborate with other CPS or contracting counterparts to undertake projects. This paper provides valuable insights into the sophisticated nexus between contracting and CPS in the international construction market. It will support business executives’ rational decision making for selecting proper contracting or CPS allies, or a proper mergers and acquisitions strategy in the international market. The paper also provides a fresh perspective through which researchers can better investigate the diversification strategies adopted by international contracting and CPS firms.
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Hurting to help or helping to hurt? The reservation wages of unemployed, job chances and reemployment incomes in Sweden Economic incentives and their impact on the job search behaviour of the unemployed have been a central focus in the academic and political debate in Sweden. A key concept has been the reservation wages of the unemployed, the lowest income at which an unemployed person would be willing to accept a job offer. Unemployment benefit systems have been argued to raise and maintain reservation wages at high levels that lower job chances. This has been supported by a large number of international studies. From this perspective lower reservation wages would function as protection against long term unemployment and the scarring effects associated with it. High reservation wages might however, based on the same behavioural assumptions, have a human capital preserving effect. The possibility to hold out for the right job should reduce human capital losses compared to accepting the first available job offer. In this article we use Swedish longitudinal micro data combining interview and register data in order to investigate three central aspects reservation wages in a Swedish context: factors influencing the setting of reservation wages, the effect of reservation wage on job chances and the impact of reservation wages on reemployment incomes. Our findings show that benefit level and pre-unemployment position in the wage structure are central factors for setting the reservation wage. The effects of reservation wages were however not the expected. No effects were found on job chances, while a strong positive effect was found on reemployment income. This together indicates that high reservation wages have a human capital preserving effect in Sweden.
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Teve-se o objetivo de verificar a possível seleção de sementes de milho - arredondadas e achatadas - no processo de semeadura com disco perfurado horizontal, bem como as conseqüências na distribuição longitudinal. Os registros dos dados deram-se pela avaliação visual de duas pessoas, com contador manual, no final da esteira carpetada em movimento de 1,54 m s-1, com 4,60 m de perspectiva para avaliação. Assim, um sensor registrava o número de orifícios do disco horizontal que devia passar pelo tubo condutor, e os espaçamentos falhos e múltiplos eram computados por pessoas diferentes. Os espaçamentos aceitáveis foram obtidos pela subtração dos espaçamentos falhos e múltiplos do total contabilizado. A medição do comprimento e espessura das sementes foi realizada com auxílio de paquímetro. Não houve alterações significativas nas variáveis estudadas, até a passagem de 55 mil orifícios do disco horizontal pelo tubo condutor; portanto, não houve seleção de sementes de milho durante a simulação do processo de semeadura.
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How do capuchin monkeys learn to use stones to crack open nuts? Perception-action theory posits that individuals explore producing varying spatial and force relations among objects and surfaces, thereby learning about affordances of such relations and how to produce them. Such learning supports the discovery of tool use. We present longitudinal developmental data from semifree-ranging tufted capuchin monkeys (Cebus apella) to evaluate predictions arising from Perception-action theory linking manipulative development and the onset of tool-using. Percussive actions bringing an object into contact with a surface appeared within the first year of life. Most infants readily struck nuts and other objects against stones or other surfaces from 6 months of age, but percussive actions alone were not sufficient to produce nut-cracking sequences. Placing the nut on the anvil surface and then releasing it, so that it could be struck with a stone, was the last element necessary for nut-cracking to appear in capuchins. Young chimpanzees may face a different challenge in learning to crack nuts: they readily place objects on surfaces and release them, but rarely vigorously strike objects against surfaces or other objects. Thus the challenges facing the two species in developing the same behavior (nut-cracking using a stone hammer and an anvil) may be quite different. Capuchins must inhibit a strong bias to hold nuts so that they can release them; chimpanzees must generate a percussive action rather than a gentle placing action. Generating the right actions may be as challenging as achieving the right sequence of actions in both species. Our analysis suggests a new direction for studies of social influence on young primates learning sequences of actions involving manipulation of objects in relation to surfaces.
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Background: In Cambodia, malaria transmission is low and most cases occur in forested areas. Seroepidemiological techniques can be used to identify both areas of ongoing transmission and high-risk groups to be targeted by control interventions. This study utilizes repeated cross-sectional data to assess the risk of being malaria sero-positive at two consecutive time points during the rainy season and investigates who is most likely to sero-convert over the transmission season. Methods: In 2005, two cross-sectional surveys, one in the middle and the other at the end of the malaria transmission season, were carried out in two ecologically distinct regions in Cambodia. Parasitological and serological data were collected in four districts. Antibodies to Plasmodium falciparum Glutamate Rich Protein (GLURP) and Plasmodium vivax Merozoite Surface Protein-119 (MSP-119) were detected using Enzyme Linked Immunosorbent Assay (ELISA). The force of infection was estimated using a simple catalytic model fitted using maximum likelihood methods. Risks for sero-converting during the rainy season were analysed using the Classification and Regression Tree (CART) method. Results: A total of 804 individuals participating in both surveys were analysed. The overall parasite prevalence was low (4.6% and 2.0% for P. falciparum and 7.9% and 6.0% for P. vivax in August and November respectively). P. falciparum force of infection was higher in the eastern region and increased between August and November, whilst P. vivax force of infection was higher in the western region and remained similar in both surveys. In the western region, malaria transmission changed very little across the season (for both species). CART analysis for P. falciparum in the east highlighted age, ethnicity, village of residence and forest work as important predictors for malaria exposure during the rainy season. Adults were more likely to increase their antibody responses to P. falciparum during the transmission season than children, whilst members of the Charay ethnic group demonstrated the largest increases. Discussion: In areas of low transmission intensity, such as in Cambodia, the analysis of longitudinal serological data enables a sensitive evaluation of transmission dynamics. Consecutive serological surveys allow an insight into spatio-temporal patterns of malaria transmission. The use of CART enabled multiple interactions to be accounted for simultaneously and permitted risk factors for exposure to be clearly identified.