869 resultados para History . Theoretical thought . Collaborative research . Concepts
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Many theoretical dissertations have an unclear definition of diversity and when interpreting strategies of organizational diversity policies, theories often contradict each other. It is argued that this ambiguity and controversy can be diminished by basing theory on diversity and diversity policy more on qualitative structured descriptive empirical comparisons.This argument is elaborated in two steps. First, diversity is shown to be a social construction: dynamic and plural in nature, dependent on the social-historical context. Second, the common theoretical dichotomy between diversity policy as equal opportunities or as diversity management in shown to be possibly misleading; empirical studies indicate more practical differentiation in types of diversity policy, manifested in public and private organizations. As qualitative comparisons are rare, especially in the European context and especially among public organizations, this article calls for more contributions of this kind and provides an analytical framework to assist scholars in the field of diversity studies.
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Integrative review (IR) has an international reputation in nursing research and evidence-based practice. This IR aimed at identifying and analyzing the concepts and methods recommended to undertaking IR in nursing. Nine information resources,including electronic databases and grey literature were searched. Seventeen studies were included. The results indicate that: primary studies were mostly from USA; it is possible to have several research questions or hypotheses and include primary studies in the review from different theoretical and methodological approaches; it is a type of review that can go beyond the analysis and synthesis of findings from primary studies allowing exploiting other research dimensions, and that presents potentialities for the development of new theories and new problems for research. Conclusion: IR is understood as a very complex type of review and it is expected to be developed using standardized and systematic methods to ensure the required rigor of scientific research and therefore the legitimacy of the established evidence.

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Nesta dissertao procura-se analisar a problemtica da Centralizao versus Descentralizao na Governao do Sistema Educativo de Cabo Verde: lgicas em anlise no perodo compreendido entre (1975 a 2006). Constata-se que Cabo Verde, depois de se tornar um pas soberano e independente, assistiu a momentos de grande concentrao e de grande centralizao na administrao do Sistema Educativo. Ao longo deste perodo assistiuse tambm a momentos de desconcentrao e de ideias de descentralizao que culminaram com a abertura do sistema poltico pluripartidrio. Essa abertura abriu a possibilidade de uma nova dinmica de transformao nos deferentes sectores da administrao do sistema educacional. As mudanas polticas verificadas no pas, permite-nos conhecer e desocultar as razes, as lgicas e as racionalidades que presidem a manuteno de um sistema centralizado de governao do Sistema Educativo, apesar da presena de foras polticas com diversidades ideolgicas. Uma vez conhecido o historial da organizao, administrao e gesto do Sistema Educativo Cabo-verdiano, a partir de uma retrospectiva histrica, debrumo-nos sobre as principais teorias que esto na base das perspectivas da centralizao e descentralizao, e seus conceitos associados enquanto modelo de anlise terica, para tentar perceber este aparente paradoxo. Na parte emprica, a metodologia utilizada apoia-se na abordagem qualitativa de investigao, na qual utilizmos a entrevista, a anlise documental e conversas informais, que nos permitiram confirmar ou infirmar a problemtica inicialmente formulada. Os dados obtidos dez entrevistados, nomeadamente os responsveis da poltica educativa, os administradores do sistema, e os directores dos estabelecimentos de ensino pblico, levam-nos a tirar vrias concluses sobre um Sistema Educativo centralizado, com uma relativa margem de autonomia. Apesar de encontrarem algumas vantagens no modelo centralizado, a maioria dos entrevistados sublinha a relevncia da opo por um modelo descentralizado de governao do Sistema Educativo.
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BACKGROUND: Strict definition of invasive aspergillosis (IA) cases is required to allow precise conclusions about the efficacy of antifungal therapy. The Global Comparative Aspergillus Study (GCAS) compared voriconazole to amphotericin B (AmB) deoxycholate for the primary therapy of IA. Because predefined definitions used for this trial were substantially different from the consensus definitions proposed by the European Organization for Research and Treatment of Cancer/Mycoses Study Group in 2008, we recategorized the 379 episodes of the GCAS according to the later definitions. METHODS: The objectives were to assess the impact of the current definitions on the classification of the episodes and to provide comparative efficacy for probable/proven and possible IA in patients treated with either voriconazole or AmB. In addition to original data, we integrated the results of baseline galactomannan serum levels obtained from 249 (65.7%) frozen samples. The original response assessment was accepted unchanged. RESULTS: Recategorization allowed 59 proven, 178 probable, and 106 possible IA cases to be identified. A higher favorable 12-week response rate was obtained with voriconazole (54.7%) than with AmB (29.9%) (P < .0001). Survival was higher for voriconazole for mycologically documented (probable/proven) IA (70.2%) than with AmB (54.9%) (P = .010). Higher response rates were obtained in possible IA treated with voriconazole vs AmB with the same magnitude of difference (26.2%; 95% confidence interval [CI], 7.2%-45.3%) as in mycologically documented episodes (24.3%; 95% CI, 11.9%-36.7%), suggesting that possible cases are true IA. CONCLUSIONS: Recategorization resulted in a better identification of the episodes and confirmed the higher efficacy of voriconazole over AmB deoxycholate in mycologically documented IA.
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Recent research has highlighted the notion that people can make judgmentsand choices by means of two systems that are labeled here tacit(or intuitive) and deliberate (or analytic). Whereas most decisionstypically involve both systems, this chapter examines the conditions underwhich each system is liable to be more effective. This aims to illuminatethe age-old issue of whether and when people should trust intuition or analysis. To do this, a framework is presented to understand how thetacit and deliberate systems work in tandem. Distinctions are also madebetween the types of information typically used by both systems as wellas the characteristics of environments that facilitate or hinder accuratelearning by the tacit system. Next, several experiments that havecontrasted intuitive and analytic modes on the same tasks are reviewed.Together, the theoretical framework and experimental evidence leads tospecifying the trade-off that characterizes their relative effectiveness.Tacit system responses can be subject to biases. In making deliberate systemresponses, however, people might not be aware of the correct rule to dealwith the task they are facing and/or make errors in executing it. Whethertacit or deliberate responses are more valid in particular circumstancesrequires assessing this trade-off. In this, the probability of making errorsin deliberate thought is postulated to be a function of the analytical complexityof the task as perceived by the person. Thus the trade-off is one of bias (inimplicit responses) versus analytical complexity (when tasks are handled indeliberate mode). Finally, it is noted that whereas much attention has beenpaid in the past to helping people make decisions in deliberate mode, effortsshould also be directed toward improving ability to make decisions intacit mode since the effectiveness of decisions clearly depends on both. Thistherefore represents an important frontier for research.
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Ces dernires annes, de nombreuses recherches ont mis en vidence les effets toxiques des micropolluants organiques pour les espces de nos lacs et rivires. Cependant, la plupart de ces tudes se sont focalises sur la toxicit des substances individuelles, alors que les organismes sont exposs tous les jours des milliers de substances en mlange. Or les effets de ces cocktails ne sont pas ngligeables. Cette thse de doctorat s'est ainsi intresse aux modles permettant de prdire le risque environnemental de ces cocktails pour le milieu aquatique. Le principal objectif a t d'valuer le risque cologique des mlanges de substances chimiques mesures dans le Lman, mais aussi d'apporter un regard critique sur les mthodologies utilises afin de proposer certaines adaptations pour une meilleure estimation du risque. Dans la premire partie de ce travail, le risque des mlanges de pesticides et mdicaments pour le Rhne et pour le Lman a t tabli en utilisant des approches envisages notamment dans la lgislation europenne. Il s'agit d'approches de screening , c'est--dire permettant une valuation gnrale du risque des mlanges. Une telle approche permet de mettre en vidence les substances les plus problmatiques, c'est--dire contribuant le plus la toxicit du mlange. Dans notre cas, il s'agit essentiellement de 4 pesticides. L'tude met galement en vidence que toutes les substances, mme en trace infime, contribuent l'effet du mlange. Cette constatation a des implications en terme de gestion de l'environnement. En effet, ceci implique qu'il faut rduire toutes les sources de polluants, et pas seulement les plus problmatiques. Mais l'approche propose prsente galement un biais important au niveau conceptuel, ce qui rend son utilisation discutable, en dehors d'un screening, et ncessiterait une adaptation au niveau des facteurs de scurit employs. Dans une deuxime partie, l'tude s'est porte sur l'utilisation des modles de mlanges dans le calcul de risque environnemental. En effet, les modles de mlanges ont t dvelopps et valids espce par espce, et non pour une valuation sur l'cosystme en entier. Leur utilisation devrait donc passer par un calcul par espce, ce qui est rarement fait d au manque de donnes cotoxicologiques disposition. Le but a t donc de comparer, avec des valeurs gnres alatoirement, le calcul de risque effectu selon une mthode rigoureuse, espce par espce, avec celui effectu classiquement o les modles sont appliqus sur l'ensemble de la communaut sans tenir compte des variations inter-espces. Les rsultats sont dans la majorit des cas similaires, ce qui valide l'approche utilise traditionnellement. En revanche, ce travail a permis de dterminer certains cas o l'application classique peut conduire une sous- ou sur-estimation du risque. Enfin, une dernire partie de cette thse s'est intresse l'influence que les cocktails de micropolluants ont pu avoir sur les communauts in situ. Pour ce faire, une approche en deux temps a t adopte. Tout d'abord la toxicit de quatorze herbicides dtects dans le Lman a t dtermine. Sur la priode tudie, de 2004 2009, cette toxicit due aux herbicides a diminu, passant de 4% d'espces affectes moins de 1%. Ensuite, la question tait de savoir si cette diminution de toxicit avait un impact sur le dveloppement de certaines espces au sein de la communaut des algues. Pour ce faire, l'utilisation statistique a permis d'isoler d'autres facteurs pouvant avoir une influence sur la flore, comme la temprature de l'eau ou la prsence de phosphates, et ainsi de constater quelles espces se sont rvles avoir t influences, positivement ou ngativement, par la diminution de la toxicit dans le lac au fil du temps. Fait intressant, une partie d'entre-elles avait dj montr des comportements similaires dans des tudes en msocosmes. En conclusion, ce travail montre qu'il existe des modles robustes pour prdire le risque des mlanges de micropolluants sur les espces aquatiques, et qu'ils peuvent tre utiliss pour expliquer le rle des substances dans le fonctionnement des cosystmes. Toutefois, ces modles ont bien sr des limites et des hypothses sous-jacentes qu'il est important de considrer lors de leur application. - Depuis plusieurs annes, les risques que posent les micropolluants organiques pour le milieu aquatique proccupent grandement les scientifiques ainsi que notre socit. En effet, de nombreuses recherches ont mis en vidence les effets toxiques que peuvent avoir ces substances chimiques sur les espces de nos lacs et rivires, quand elles se retrouvent exposes des concentrations aigus ou chroniques. Cependant, la plupart de ces tudes se sont focalises sur la toxicit des substances individuelles, c'est dire considres sparment. Actuellement, il en est de mme dans les procdures de rgulation europennes, concernant la partie valuation du risque pour l'environnement d'une substance. Or, les organismes sont exposs tous les jours des milliers de substances en mlange, et les effets de ces "cocktails" ne sont pas ngligeables. L'valuation du risque cologique que pose ces mlanges de substances doit donc tre abord par de la manire la plus approprie et la plus fiable possible. Dans la premire partie de cette thse, nous nous sommes intresss aux mthodes actuellement envisages tre intgres dans les lgislations europennes pour l'valuation du risque des mlanges pour le milieu aquatique. Ces mthodes sont bases sur le modle d'addition des concentrations, avec l'utilisation des valeurs de concentrations des substances estimes sans effet dans le milieu (PNEC), ou partir des valeurs des concentrations d'effet (CE50) sur certaines espces d'un niveau trophique avec la prise en compte de facteurs de scurit. Nous avons appliqu ces mthodes deux cas spcifiques, le lac Lman et le Rhne situs en Suisse, et discut les rsultats de ces applications. Ces premires tapes d'valuation ont montr que le risque des mlanges pour ces cas d'tude atteint rapidement une valeur au dessus d'un seuil critique. Cette valeur atteinte est gnralement due deux ou trois substances principales. Les procdures proposes permettent donc d'identifier les substances les plus problmatiques pour lesquelles des mesures de gestion, telles que la rduction de leur entre dans le milieu aquatique, devraient tre envisages. Cependant, nous avons galement constat que le niveau de risque associ ces mlanges de substances n'est pas ngligeable, mme sans tenir compte de ces substances principales. En effet, l'accumulation des substances, mme en traces infimes, atteint un seuil critique, ce qui devient plus difficile en terme de gestion du risque. En outre, nous avons soulign un manque de fiabilit dans ces procdures, qui peuvent conduire des rsultats contradictoires en terme de risque. Ceci est li l'incompatibilit des facteurs de scurit utiliss dans les diffrentes mthodes. Dans la deuxime partie de la thse, nous avons tudi la fiabilit de mthodes plus avances dans la prdiction de l'effet des mlanges pour les communauts voluant dans le systme aquatique. Ces mthodes reposent sur le modle d'addition des concentrations (CA) ou d'addition des rponses (RA) appliqus sur les courbes de distribution de la sensibilit des espces (SSD) aux substances. En effet, les modles de mlanges ont t dvelopps et valids pour tre appliqus espce par espce, et non pas sur plusieurs espces agrges simultanment dans les courbes SSD. Nous avons ainsi propos une procdure plus rigoureuse, pour l'valuation du risque d'un mlange, qui serait d'appliquer d'abord les modles CA ou RA chaque espce sparment, et, dans une deuxime tape, combiner les rsultats afin d'tablir une courbe SSD du mlange. Malheureusement, cette mthode n'est pas applicable dans la plupart des cas, car elle ncessite trop de donnes gnralement indisponibles. Par consquent, nous avons compar, avec des valeurs gnres alatoirement, le calcul de risque effectu selon cette mthode plus rigoureuse, avec celle effectue traditionnellement, afin de caractriser la robustesse de cette approche qui consiste appliquer les modles de mlange sur les courbes SSD. Nos rsultats ont montr que l'utilisation de CA directement sur les SSDs peut conduire une sous-estimation de la concentration du mlange affectant 5 % ou 50% des espces, en particulier lorsque les substances prsentent un grand cart- type dans leur distribution de la sensibilit des espces. L'application du modle RA peut quant lui conduire une sur- ou sous-estimations, principalement en fonction de la pente des courbes dose- rponse de chaque espce composant les SSDs. La sous-estimation avec RA devient potentiellement importante lorsque le rapport entre la EC50 et la EC10 de la courbe dose-rponse des espces est plus petit que 100. Toutefois, la plupart des substances, selon des cas rels, prsentent des donnes d' cotoxicit qui font que le risque du mlange calcul par la mthode des modles appliqus directement sur les SSDs reste cohrent et surestimerait plutt lgrement le risque. Ces rsultats valident ainsi l'approche utilise traditionnellement. Nanmoins, il faut garder l'esprit cette source d'erreur lorsqu'on procde une valuation du risque d'un mlange avec cette mthode traditionnelle, en particulier quand les SSD prsentent une distribution des donnes en dehors des limites dtermines dans cette tude. Enfin, dans la dernire partie de cette thse, nous avons confront des prdictions de l'effet de mlange avec des changements biologiques observs dans l'environnement. Dans cette tude, nous avons utilis des donnes venant d'un suivi long terme d'un grand lac europen, le lac Lman, ce qui offrait la possibilit d'valuer dans quelle mesure la prdiction de la toxicit des mlanges d'herbicide expliquait les changements dans la composition de la communaut phytoplanctonique. Ceci ct d'autres paramtres classiques de limnologie tels que les nutriments. Pour atteindre cet objectif, nous avons dtermin la toxicit des mlanges sur plusieurs annes de 14 herbicides rgulirement dtects dans le lac, en utilisant les modles CA et RA avec les courbes de distribution de la sensibilit des espces. Un gradient temporel de toxicit dcroissant a pu tre constat de 2004 2009. Une analyse de redondance et de redondance partielle, a montr que ce gradient explique une partie significative de la variation de la composition de la communaut phytoplanctonique, mme aprs avoir enlev l'effet de toutes les autres co-variables. De plus, certaines espces rvles pour avoir t influences, positivement ou ngativement, par la diminution de la toxicit dans le lac au fil du temps, ont montr des comportements similaires dans des tudes en msocosmes. On peut en conclure que la toxicit du mlange herbicide est l'un des paramtres cls pour expliquer les changements de phytoplancton dans le lac Lman. En conclusion, il existe diverses mthodes pour prdire le risque des mlanges de micropolluants sur les espces aquatiques et celui-ci peut jouer un rle dans le fonctionnement des cosystmes. Toutefois, ces modles ont bien sr des limites et des hypothses sous-jacentes qu'il est important de considrer lors de leur application, avant d'utiliser leurs rsultats pour la gestion des risques environnementaux. - For several years now, the scientists as well as the society is concerned by the aquatic risk organic micropollutants may pose. Indeed, several researches have shown the toxic effects these substances may induce on organisms living in our lakes or rivers, especially when they are exposed to acute or chronic concentrations. However, most of the studies focused on the toxicity of single compounds, i.e. considered individually. The same also goes in the current European regulations concerning the risk assessment procedures for the environment of these substances. But aquatic organisms are typically exposed every day simultaneously to thousands of organic compounds. The toxic effects resulting of these "cocktails" cannot be neglected. The ecological risk assessment of mixtures of such compounds has therefore to be addressed by scientists in the most reliable and appropriate way. In the first part of this thesis, the procedures currently envisioned for the aquatic mixture risk assessment in European legislations are described. These methodologies are based on the mixture model of concentration addition and the use of the predicted no effect concentrations (PNEC) or effect concentrations (EC50) with assessment factors. These principal approaches were applied to two specific case studies, Lake Geneva and the River Rhne in Switzerland, including a discussion of the outcomes of such applications. These first level assessments showed that the mixture risks for these studied cases exceeded rapidly the critical value. This exceeding is generally due to two or three main substances. The proposed procedures allow therefore the identification of the most problematic substances for which management measures, such as a reduction of the entrance to the aquatic environment, should be envisioned. However, it was also showed that the risk levels associated with mixtures of compounds are not negligible, even without considering these main substances. Indeed, it is the sum of the substances that is problematic, which is more challenging in term of risk management. Moreover, a lack of reliability in the procedures was highlighted, which can lead to contradictory results in terms of risk. This result is linked to the inconsistency in the assessment factors applied in the different methods. In the second part of the thesis, the reliability of the more advanced procedures to predict the mixture effect to communities in the aquatic system were investigated. These established methodologies combine the model of concentration addition (CA) or response addition (RA) with species sensitivity distribution curves (SSD). Indeed, the mixture effect predictions were shown to be consistent only when the mixture models are applied on a single species, and not on several species simultaneously aggregated to SSDs. Hence, A more stringent procedure for mixture risk assessment is proposed, that would be to apply first the CA or RA models to each species separately and, in a second step, to combine the results to build an SSD for a mixture. Unfortunately, this methodology is not applicable in most cases, because it requires large data sets usually not available. Therefore, the differences between the two methodologies were studied with datasets created artificially to characterize the robustness of the traditional approach applying models on species sensitivity distribution. The results showed that the use of CA on SSD directly might lead to underestimations of the mixture concentration affecting 5% or 50% of species, especially when substances present a large standard deviation of the distribution from the sensitivity of the species. The application of RA can lead to over- or underestimates, depending mainly on the slope of the dose-response curves of the individual species. The potential underestimation with RA becomes important when the ratio between the EC50 and the EC10 for the dose-response curve of the species composing the SSD are smaller than 100. However, considering common real cases of ecotoxicity data for substances, the mixture risk calculated by the methodology applying mixture models directly on SSDs remains consistent and would rather slightly overestimate the risk. These results can be used as a theoretical validation of the currently applied methodology. Nevertheless, when assessing the risk of mixtures, one has to keep in mind this source of error with this classical methodology, especially when SSDs present a distribution of the data outside the range determined in this study Finally, in the last part of this thesis, we confronted the mixture effect predictions with biological changes observed in the environment. In this study, long-term monitoring of a European great lake, Lake Geneva, provides the opportunity to assess to what extent the predicted toxicity of herbicide mixtures explains the changes in the composition of the phytoplankton community next to other classical limnology parameters such as nutrients. To reach this goal, the gradient of the mixture toxicity of 14 herbicides regularly detected in the lake was calculated, using concentration addition and response addition models. A decreasing temporal gradient of toxicity was observed from 2004 to 2009. Redundancy analysis and partial redundancy analysis showed that this gradient explains a significant portion of the variation in phytoplankton community composition, even when having removed the effect of all other co-variables. Moreover, some species that were revealed to be influenced positively or negatively, by the decrease of toxicity in the lake over time, showed similar behaviors in mesocosms studies. It could be concluded that the herbicide mixture toxicity is one of the key parameters to explain phytoplankton changes in Lake Geneva. To conclude, different methods exist to predict the risk of mixture in the ecosystems. But their reliability varies depending on the underlying hypotheses. One should therefore carefully consider these hypotheses, as well as the limits of the approaches, before using the results for environmental risk management
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Background: To compare the different schemes that have been proposed during the last thirteen years to explain the renewal of the corneal epithelium. Material and Methods:We analyzed all the data present in the literature to explain the renewal of the corneal epithelium in mammals. According to the schemes proposed in the literature we developed a 3D animation to facilitate the understanding of the different concepts. Results:Three different schemes have been proposed to explain the renewal of the corneal epithelium in mammals during the last thirteen years. 1950-1981: the corneal epithelium was thought being renewed by mitosis of cells located in the basal layer. At this time scientist were not talking about stem cells. 1981-1986 was the period of the "XYZ hypothesis" or the transdifferentiation paradigm. At this time the conjunctival epithelium renewed the corneal epithelium in a centripetal migration. 1986-2008: the limbal stem cell paradigm, there were no stem cells in the corneal epithelium, all the corneal stem cells were located in the limbus and renewed the central cornea after a migration of 6 to 7 mm of transient amplifying cells toward the centre of the cornea. 2008, epithelial stem cells were found in the central cornea in mammals (Nature, Majo et al. November 2008). Discussion:We thought that the renewal of the corneal epithelium was completely defined. According to the last results we published in Nature, the current paradigm will be revisited. The experiments we made were on animals and the final demonstration on human has still to be done. If we find the same results in human, a new paradigm will be define and will change the way we consider ocular surface therapy and reconstruction.
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In the past three decades, feminists and critical theorists have discussed and argued the importance of deconstructing and problematizing social science research methodology in order to question normalized hierarchies concerning the production of knowledge and the status of truth claims. Nevertheless, often, these ideas have basically remained theoretical propositions not embodied in research practices. In fact there is very little published discussion about the difficulties and limits of their practical application. In this paper we introduce some interconnected reflections starting from two different but related experiences of embodying 'feminist activist research'. Our aim is to emphasise the importance of attending to process, making mistakes and learning during fieldwork, as well as experimenting with personalized forms of analysis, such as the construction of narratives and the story-telling process.
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In the past three decades, feminists and critical theorists have discussed and argued the importance of deconstructing and problematizing social science research methodology in order to question normalized hierarchies concerning the production of knowledge and the status of truth claims. Nevertheless, often, these ideas have basically remained theoretical propositions not embodied in research practices. In fact there is very little published discussion about the difficulties and limits of their practical application. In this paper we introduce some interconnected reflections starting from two different but related experiences of embodying 'feminist activist research'. Our aim is to emphasise the importance of attending to process, making mistakes and learning during fieldwork, as well as experimenting with personalized forms of analysis, such as the construction of narratives and the story-telling process.
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A workshop recently held at the Ecole Polytechnique Federale de Lausanne (EPFL, Switzerland) was dedicated to understanding the genetic basis of adaptive change, taking stock of the different approaches developed in theoretical population genetics and landscape genomics and bringing together knowledge accumulated in both research fields. Indeed, an important challenge in theoretical population genetics is to incorporate effects of demographic history and population structure. But important design problems (e.g. focus on populations as units, focus on hard selective sweeps, no hypothesis-based framework in the design of the statistical tests) reduce their capability of detecting adaptive genetic variation. In parallel, landscape genomics offers a solution to several of these problems and provides a number of advantages (e.g. fast computation, landscape heterogeneity integration). But the approach makes several implicit assumptions that should be carefully considered (e.g. selection has had enough time to create a functional relationship between the allele distribution and the environmental variable, or this functional relationship is assumed to be constant). To address the respective strengths and weaknesses mentioned above, the workshop brought together a panel of experts from both disciplines to present their work and discuss the relevance of combining these approaches, possibly resulting in a joint software solution in the future.