984 resultados para Change-points


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Business organisations are excellent representations of what in physics and mathematics are designated "chaotic" systems. Because a culture of innovation will be vital for organisational survival in the 21st century, the present paper proposes that viewing organisations in terms of "complexity theory" may assist leaders in fine-tuning managerial philosophies that provide orderly management emphasizing stability within a culture of organised chaos, for it is on the "boundary of chaos" that the greatest creativity occurs. It is argued that 21st century companies, as chaotic social systems, will no longer be effectively managed by rigid objectives (MBO) nor by instructions (MBI). Their capacity for self-organisation will be derived essentially from how their members accept a shared set of values or principles for action (MBV). Complexity theory deals with systems that show complex structures in time or space, often hiding simple deterministic rules. This theory holds that once these rules are found, it is possible to make effective predictions and even to control the apparent complexity. The state of chaos that self-organises, thanks to the appearance of the "strange attractor", is the ideal basis for creativity and innovation in the company. In this self-organised state of chaos, members are not confined to narrow roles, and gradually develop their capacity for differentiation and relationships, growing continuously toward their maximum potential contribution to the efficiency of the organisation. In this way, values act as organisers or "attractors" of disorder, which in the theory of chaos are equations represented by unusually regular geometric configurations that predict the long-term behaviour of complex systems. In business organisations (as in all kinds of social systems) the starting principles end up as the final principles in the long term. An attractor is a model representation of the behavioral results of a system. The attractor is not a force of attraction or a goal-oriented presence in the system; it simply depicts where the system is headed based on its rules of motion. Thus, in a culture that cultivates or shares values of autonomy, responsibility, independence, innovation, creativity, and proaction, the risk of short-term chaos is mitigated by an overall long-term sense of direction. A more suitable approach to manage the internal and external complexities that organisations are currently confronting is to alter their dominant culture under the principles of MBV.

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Many metropolitan areas have experienced extreme boom-bust cycles over the past century. Some places, like Detroit, grew enormously as industrial powerhouses and then declined, while other older cities, like Boston, seem quite resilient. Education does a reasonable job of explaining urban resilience. In this paper, we present a simple model where education increases the level of entrepreneurship. In this model, human capital spillovers occur at the city level because skilled workers produce more product varieties and thereby increase labor demand. We decompose empirically the causes of the connection between skills and urban success and find that skills are associated with growth in productivity or entrepreneurship, not with growth in quality of life, at least outside of the West. We also find that skills seem to have depressed housing supply growth in the West, but not in other regions, which supports the view that educated residents in that region have fought for tougher land-use controls. We also present evidence that skills have had a disproportionately large impact on unemployment during the current recession.

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Over the past two decades, technological progress has been biased towards making skilled labor more productive. The evidence for this finding is based on the persistent parallel increase in the skill premium and the supply of skilled workers. What are the implications of skill-biased technological change for the business cycle? To answer this question, we use the CPS outgoing rotation groups to construct quarterly series for the price and quantity of skill. The unconditional correlation of the skill premium with the cycle is zero. However, using a structural VAR with long run restrictions, we find that technology shocks substantially increase the premium. Investment-specific technology shocks are not skill-biased and our findings suggest that capital and skill are (mildly) substitutable in aggregate production.

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If financial deepening aids economic growth, then financial repression should be harmful. We use a natural experiment – the change in the English usury laws in 1714 – to analyze the effects of interest rate restrictions. We use a sample of individual loan transactions to demonstrate how the reduction of the legal maximum rate of interest affected the supply and demand for credit. Average loan size and minimum loan size increased strongly, and access to credit worsened for those with little ‘social capital.’ While we have no direct evidence that loans were misallocated, the discontinuity in loan receipts makes this highly likely. We conclude that financial repression can undermine the positive effects of financial deepening.

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We did a subject-level meta-analysis of the changes (Δ) in blood pressure (BP) observed 3 and 6 months after renal denervation (RDN) at 10 European centers. Recruited patients (n=109; 46.8% women; mean age 58.2 years) had essential hypertension confirmed by ambulatory BP. From baseline to 6 months, treatment score declined slightly from 4.7 to 4.4 drugs per day. Systolic/diastolic BP fell by 17.6/7.1 mm Hg for office BP, and by 5.9/3.5, 6.2/3.4, and 4.4/2.5 mm Hg for 24-h, daytime and nighttime BP (P0.03 for all). In 47 patients with 3- and 6-month ambulatory measurements, systolic BP did not change between these two time points (P0.08). Normalization was a systolic BP of <140 mm Hg on office measurement or <130 mm Hg on 24-h monitoring and improvement was a fall of 10 mm Hg, irrespective of measurement technique. For office BP, at 6 months, normalization, improvement or no decrease occurred in 22.9, 59.6 and 22.9% of patients, respectively; for 24-h BP, these proportions were 14.7, 31.2 and 34.9%, respectively. Higher baseline BP predicted greater BP fall at follow-up; higher baseline serum creatinine was associated with lower probability of improvement of 24-h BP (odds ratio for 20-μmol l(-1) increase, 0.60; P=0.05) and higher probability of experiencing no BP decrease (OR, 1.66; P=0.01). In conclusion, BP responses to RDN include regression-to-the-mean and remain to be consolidated in randomized trials based on ambulatory BP monitoring. For now, RDN should remain the last resort in patients in whom all other ways to control BP failed, and it must be cautiously used in patients with renal impairment.

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The late Early Triassic sedimentary-facies evolution and carbonate carbon-isotope marine record (delta(13)C(carb)) of ammonoid-rich, outer platform settings show striking similarities between the South ChinaBlock (SCB) and the widely distant Northern Indian Margin (NIM). The studied sections are located within the Triassic Tethys Himalayan belt (Losar section, Himachal Pradesh, India) and the Nanpanjiang Basin in the South China Block (Jinya section, Guangxi Province), respectively. Carbon isotopes from the studied sections confirm the previously observed carbon cycle perturbations at a time of major paleoceanographic changes in the wake of the end-Permian biotic crisis. This study documents the coincidence between a sharp increase in the carbon isotope composition and the worldwide ammonoid evolutionary turnover (extinction followed by a radiation) occurring around the Smithian-Spathian boundary. Based on recent modeling studies on ammonoid paleobiogeography and taxonomic diversity, we demonstrate that the late Early Triassic (Smithian and Spathian) was a time of a major climate change. More precisely, the end Smithian climate can be characterized by a warm and equable climate underlined by a flat, pole-to-equator, sea surface temperature (SST) gradient, while the steep Spathian SST gradient suggests latitudinally differentiated climatic conditions. Moreover, sedimentary evidence suggests a transition from a humid and hot climate during the Smithian to a dryer climate from the Spathian onwards. By analogy with comparable carbon isotope perturbations in the Late Devonian, Jurassic and Cretaceous we propose that high atmospheric CO(2) levels could have been responsible for the observed carbon cycle disturbance at the Smithian-Spathian boundary. We suggest that the end Smithian ammonoid extinction has been essentially caused by a warm and equable climate related to an increased CO(2) flux possibly originating from a short eruptive event of the Siberian igneous province. This increase in atmospheric CO(2) concentrations could have additionally reduced the marine calcium carbonate oversaturation and weakened the calcification potential of marine organisms, including ammonoids, in late Smithian oceans. (c) 2006 Elsevier B.V. All rights reserved.

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By the end of the 1970s, contaminated sites had emerged as one of the most complex and urgent environmental issues affecting industrialized countries. The authors show that small and prosperous Switzerland is no exception to the pervasive problem of sites contamination, the legacy of past practices in waste management having left some 38,000 contaminated sites throughout the country. This book outlines the problem, offering evidence that open and polycentric environmental decision-making that includes civil society actors is valuable. They propose an understanding of environmental management of contaminated sites as a political process in which institutions frame interactions between strategic actors pursuing sometimes conflicting interests. In the opening chapter, the authors describe the influences of politics and the power relationships between actors involved in decision-making in contaminated sites management, which they term a "wicked problem." Chapter Two offers a theoretical framework for understanding institutions and the environmental management of contaminated sites. The next five chapters present a detailed case study on environmental management and contaminated sites in Switzerland, focused on the Bonfol Chemical Landfill. The study and analysis covers the establishment of the landfill under the first generation of environmental regulations, its closure and early remediation efforts, and the gambling on the remediation objectives, methods and funding in the first decade of the 21st Century. The concluding chapter discusses the question of whether the strength of environmental regulations, and the type of interactions between public, private, and civil society actors can explain the environmental choices in contaminated sites management. Drawing lessons from research, the authors debate the value of institutional flexibility for dealing with environmental issues such as contaminated sites.

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Abstract : The role of order effects has been widely shown and discussed in areas such as memory and social impression formation. This work focuses in a first half on order effects influencing the verdict chosen at the end of a criminal trial. Contrary to impression formation but according to trial's characteristics, it has been hypothesised that a recency effect would influence the verdict's choice. Three groups of students (N = 576) received a mock trial resume with a specific order stemming from the combination of three witnesses, one expert and two ocular witnesses. Results show a recency effect, the last testimony provoking significantly more acquittals if discriminating, and more condemnations if incriminating. The second half of this work starts from Gestalt and sociopsychological researches presenting numerous insights into cognitive organization of perceptions and opinions. It has been postulated that a witness probative value will change according to the emitted verdict, an incriminating witness or expert possessing a higher probative value in a condemning verdict than in an innocenting one, on the other hand a discriminating witness or expert having a higher probative value in an acquittal than in a condemnation. Results using a seven points scale measuring witnesses' probative value confirm this hypothesis. Argumentations written by the subjects to explain their verdict and refering to the accusing expert also show a congruency effect as categories of arguments are identical in case of condemnation or acquittal, the only difference between both types of verdicts residing in the frequency of these categories following the judgement, higher use of incriminating arguments in case of guiltiness and higher use of discriminating ones if the accused is found innocent. Résumé : L'intervention des effets sériels a fait l'objet de nombreuses recherches dans le domaine de la mémoire et de la formation d'impression en psychologie sociale. Ce travail s'intéresse dans une première partie aux effets d'ordre pouvant influencer le choix du verdict à la fin d'un procès pénal. Contrairement aux résultats obtenus en matière de formation d'impression, mais conformément aux caractéristiques d'un procès, l'hypothèse de l'intervention d'un effet de récence a été formulée, affirmant que les derniers témoins influencent le plus le choix du verdict. Trois groupes d'étudiants (N = 576) ont lu le résumé d'un procès fictif présentant trois témoignages, deux témoins visuels à décharge et un expert à charge. Chaque groupe recevait un ordre spécifique de présentation des témoins de sorte que l'expert se trouvait en première, deuxième ou troisième position. Les résultats montrent un effet de récence, le dernier témoin provoquant davantage d'acquittements s'il est disculpant et davantage de condamnations s'il est inculpant. La seconde partie de ce travail émane des recherches effectuées dans le domaine de la théorie de la forme et de la psychologie sociale ayant un intérêt marqué pour l'organisation cognitive de nos perceptions et de nos opinions. L'hypothèse que nous avons posée souligne le lien entretenu entre l'évaluation de la force probante d'un témoin et le verdict émis : un témoignage discriminant possédera plus de poids en cas d'acquittement qu'en cas de condamnation, inversement un témoignage incriminant aura plus de poids en cas de condamnation qu'en cas d'acquittement. L'utilisation d'une échelle en sept points mesurant la force probante des deux types de témoins confirme cette hypothèse, l'estimation de la valeur accordée à un même témoin variant selon le type de verdict choisi. Les argumentations de chaque verdict ont également montré que les catégories d'arguments se référant à l'expert étaient identiques en cas de condamnation ou d'acquittement de l'inculpé, par contre les fréquences de ces catégories entretiennent un lien congruent avec le verdict, celles inculpantes étant majoritairement utilisées pour asseoir la culpabilité mais peu représentées en cas d'acquittement, inversement celles disculpantes apparaissant bien plus lorsqu'il s'agit d'innocenter l'inculpé que pour le condamner.

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INTRODUCTION: Quitting smoking is associated with weight gain, which may threaten motivation to engage or sustain a quit attempt. The pattern of weight gained by smokers treated according to smoking cessation guidelines has been poorly described. We aimed to determine the weight gained after smoking cessation and its predictors, by smokers receiving individual counseling and nicotine replacement therapies for smoking cessation. METHODS: We performed an ancillary analysis of a randomized controlled trial assessing moderate physical activity as an aid for smoking cessation in addition to standard treatment in sedentary adult smokers. We used mixed longitudinal models to describe the evolution of weight over time, thus allowing us to take every participant into account. We also fitted a model to assess the effect of smoking status and reported use of nicotine replacement therapy at each time point. We adjusted for intervention group, sex, age, nicotine dependence, and education. RESULTS: In the whole cohort, weight increased in the first 3 months, and stabilized afterwards. Mean 1-year weight gain was 3.3kg for women and 3.9kg for men (p = .002). Higher nicotine dependence and male sex were associated with more weight gained during abstinence. Age over median was associated with continuing weight gain during relapse. There was a nonsignificant trend toward slower weight gain with use of nicotine replacement therapies. CONCLUSION: Sedentary smokers receiving a standard smoking cessation intervention experience a moderate weight gain, limited to the first 3 months. Older age, male sex, and higher nicotine dependence are predictors of weight gain.

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II Resumo Cabo Verde é um país que tem acompanhado as grandes mudanças políticas, sociais, económicas e educativas, atribuindo um papel preponderante aos professores na educação/formação dos indivíduos. Neste sentido a formação inicial não pode constituir um acto “acabado” que não tem em linha de conta as mudanças que decorrem no seu seio. A formação contínua aparece com um processo de construção da mudança, apoiado no desenvolvimento profissional dos professores. A avaliação de necessidade de formação em professores do ensino secundário em Cabo Verde é o tema do trabalho de investigação, realizado nas escolas secundárias da ilha de Santo Antão, em Cabo Verde, no sentido de identificar questões problemáticas na formação inicial e contínua de professores e as suas implicações na qualidade educativa. Neste sentido, ao longo de 5 capítulos apresentamos os pontos desta investigação, estruturados de forma a se poder acompanhar a sua evolução. No 1º capítulo, apresenta-se a Problemática de Investigação, que constitui a parte inicial da dissertação, pela exposição do quadro conceptual do ensino secundário em Cabo Verde através da contextualização e identificação do problema, da formulação dos objectivos e questões de investigação. No 2º capítulo faz-se o percurso histórico/educativo de Cabo Verde, desde a época colonial, passando pela educação após a independência em 1975, à constituição da Lei de Bases do Sistema Educativo e a Reforma Educativa dos anos 90. No 3º capítulo, intitulado “A Formação Inicial e Continua de Professores em Cabo Verde”, é abordado o enquadramento teórico desta investigação, com referência à contextualização geral da formação e modelos de formação de professores, evoluindo para a realidade Cabo-verdiana, tendo em consideração as instituições de formação de professores e o contexto actual do ensino secundário em Cabo Verde. No 4º capítulo faz-se a apresentação da Metodologia de Investigação, adoptada num estudo extensivo, do qual abordamos a natureza da investigação e caracterizamos a amostra e respondentes. Como técnicas de recolha de dados, são utilizados: o inquérito por questionário (n=77), a professores do ensino secundário e o inquérito por entrevista (n=9), aos directores das escolas secundárias da ilha de Santo Antão e a formadores de professores em São Vicente. Como técnica de análise de dados, são utilizados diversos procedimentos estatísticos e a análise de conteúdo. O 5º capítulo corresponde a apresentação e discussão dos resultados da investigação desses três públicos analisados. Para finalizar, apresenta-se uma conclusão que corresponde a síntese dos resultados obtidos, propostas de sugestões de melhoria e limitações do estudo. Cabo Verde is a country willing to follow the great political, social, economic and educational changes. This important role have attributed to teachers to educate and train individuals. In this sense the initial training cannot be considered as a “finished” task without taking into consideration those changes. The in service training appears as a scientific and pedagogic autonomization towards the growing change. The Evaluation of Secondary School teacher training Needs in Cabo Verde constitutes an investigation work, carried out in Santo Antão's island Secondary schools, aiming to identify problems in initial and continuous teachers' training and their implications in the educational quality. In this sense, along five chapters we will present the points of this investigation, structured to facilitate the understanding of its evolution. In the first chapter we present the Problem of Investigation which is an introductory part of the dissertation, the conceptual theory of the Cabo Verde secondary education through the contextualization and identification of the problem, the formulation of the objectives and investigation issues. In the second chapter we present the Cabo Verde historical/educational background, from the colonial time, going through after independence in 1975, to the constitution of the Basic Educational Law of the System and the nineties Educational Reform. In the third chapter entitled “The Initial and in-service Teacher´s Training in Cabo Verde” brings the theoretical framework of this investigation, where we present a general contextualization of teachers' training and models, developed from the reality of Cabo Verde. In this regard we will consider the teachers' training institutions and the current secondary education context in Cabo Verde. In the fourth chapter we present the Research Methodology, adopted in an extensive study, of which we draw the nature of the investigation and we characterized the sample. We carried out questionnaire (n=77) to teachers, interviews (n=9) to headmasters from Santo Antão's island secondary schools and trainers from São Vicente. We used statistical analyses and content analyses as data analyse techniques. The fifth chapter deals with presentation the discussion of results of those three analyzed publics' investigation. Finally, we present a summary of the obtained results, suggestions for improvement and limitations of study.

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1 Insect pests, biological invasions and climate change are considered to representmajor threats to biodiversity, ecosystem functioning, agriculture and forestry.Deriving hypothesis of contemporary and/or future potential distributions of insectpests and invasive species is becoming an important tool for predicting the spatialstructure of potential threats.2 The western corn rootworm (WCR) Diabrotica virgifera virgifera LeConte is apest of maize in North America that has invaded Europe in recent years, resultingin economic costs in terms of maize yields in both continents. The present studyaimed to estimate the dynamics of potential areas of invasion by the WCR under aclimate change scenario in the Northern Hemisphere. The areas at risk under thisscenario were assessed by comparing, using complementary approaches, the spatialprojections of current and future areas of climatic favourability of the WCR. Spatialhypothesis were generated with respect to the presence records in the native rangeof the WCR and physiological thresholds from previous empirical studies.3 We used a previously developed protocol specifically designed to estimatethe climatic favourability of the WCR. We selected the most biologicallyrelevant climatic predictors and then used multidimensional envelope (MDE) andMahalanobis distances (MD) approaches to derive potential distributions for currentand future climatic conditions.4 The results obtained showed a northward advancement of the upper physiologicallimit as a result of climate change, which might increase the strength of outbreaksat higher latitudes. In addition, both MDE and MD outputs predict the stability ofclimatic favourability for the WCR in the core of the already invaded area in Europe,which suggests that this zone would continue to experience damage from this pestin Europe.

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During adolescence, cognitive abilities increase robustly. To search for possible related structural alterations of the cerebral cortex, we measured neuronal soma dimension (NSD = width times height), cortical thickness and neuronal densities in different types of neocortex in post-mortem brains of five 12-16 and five 17-24 year-olds (each 2F, 3M). Using a generalized mixed model analysis, mean normalized NSD comparing the age groups shows layer-specific change for layer 2 (p < .0001) and age-related differences between categorized type of cortex: primary/primary association cortex (BA 1, 3, 4, and 44) shows a generalized increase; higher-order regions (BA 9, 21, 39, and 45) also show increase in layers 2 and 5 but decrease in layers 3, 4, and 6 while limbic/orbital cortex (BA 23, 24, and 47) undergoes minor decrease (BA 1, 3, 4, and 44 vs. BA 9, 21, 39, and 45: p = .036 and BA 1, 3, 4, and 44 vs. BA 23, 24, and 47: p = .004). These data imply the operation of cortical layer- and type-specific processes of growth and regression adding new evidence that the human brain matures during adolescence not only functionally but also structurally.