1,087 research outputs found
Monitoring Employment Quality in Europe: European Employment Strategy Indicators and Beyond
Comparison of job quality according to Laeken indicators reveals a strong heterogeneity of national performancesjob quality; European comparisons; labour market
A Taxonomy of European Labour Markets Using Quality Indicators
The report proposes a critical approach of European job quality indicators. It relies on both theoreti-cal and empirical analysis, and shows the necessity to introduce complementary variables, such as wages, working conditions and training duration. Comparative results for the EU 27 confirm the heterogeneity of job quality across Europe. Besides, time series analysis shows an upward trend of job quality in Europe since 1994, with a few exceptions. On the whole empirical investigations do not reveal any trade off between quantitative performances and job quality levels.Labour market comparisons, job quality, European Employment Strategy, training and education policies, working conditions, gender
Le New Deal for Young People: des évaluations contrastées
Les évaluations britanniques du New Deal for Young people (NDYP), programme emblématique du Welfare to Work, en font un bilan nuancé. Après un rappel des objectifs et des composantes du programme, l'article passe en revue les concepts, théories et croyances qui ont soutenu l'action du gouvernement en matière d'emploi. Les études d'évaluation et les choix méthodologiques des chercheurs sont détaillés : matching, modélisation de type WS/PS, méthode de différence de différences, estimation par appariement, etc. Les conclusions sont contrastées : le NDYP réduit le chômage de long terme, mais la situation des bénéficiaires restent précaires à la sortie du programme. Il garantit rarement un emploi de qualité et renforce souvent les inégalités sur le marché du travail. Le programme semble impuissant face à la segmentation du marché du travail, son impact macroéconomique reste discutable
Cross-country differences in the long-run economic impacts of increased fertility
Higher fertility slowly increases the workers-to-retirees ratio over the long run, which can ease the pension financing challenge brought about by population aging. It may or may not increase production per capita. Existing simulation studies all find a positive impact on public finances over the long run. They however differ on the impact on output per capita. Whether differences are due to model designs or country characteristics is unknown. Using the same macroeconomic model for a sample of 14 European countries, I find that the long-run pension deficits are reduced 27% on average, if one woman out of five had one more child in her lifetime. Variations across countries are small. On the other hand, I find that output per capita increases in all countries from my sample, with one exception. Differences in population structures, ageproductivity profiles and pension systems can explain the exception. Fertility-promoting policies will always ease the public finance challenge due to population aging, but may worsen output per capita if pension payments are too loosely connected to earnings histories or if age-productivity profiles are very steep
Modelling and analysis of neurons coupled by electrical synapses
The objective of this thesis is to analyze the role of the intrinsic properties of neurons in the communication through electrical synapses. Mesencephalic trigeminal neurons constitute an excellent experimental model to study the communication between neurons, because of its easy experimental access experimental and simple to model and analyze a biological system. Among the contributions of this thesis are: the complete modeling of the sodium currents and other ionic current (and its modulation); the explanation preference subthreshold frequency transfer between
neuronfor example and its coupling. Some preliminary results of this work have been presented at international
conferences.morphology. However, the analysis of real neurons is limited by experimental constraints that do not allow to explore all aspects of the model. Within the context of this thesis, a mathematical model is built, based on electrophysiological recordings made by Sebastián Curti at the School of Medicine of Universidad de la República. The model consists of a set of differential equations, which can be represented by a nonlinear electrical circuit. Some of the differential equations are obtained from literature and only some minor parameters’ adjustments are made. Moreover, during the thesis we have found that more data was needed in order to explain some of the most important features of the behavior of neurons, such as the duration of the action potential. Therefore, more experimental
recordings were made, allowing to refine the model. The model allows to evaluate the response of the neuron to different stimuli (currents or voltages imposed by an electrode), making possible to make new “experiments” that are not possible in a laboratory. Alternatives models are analyzed (varying ionic currents and morphology) using experimental information to validate them. Then the model is used to understand some unusual features of the communication between neurons. First, it is studied the subthreshold transfer function (i.e. without action potentials) between neurons coupled by electrical synapses. A reduced model is used and then linearized, in order to derive an
analytical expression of the transfer function, whose behaviour is consistent with experimental results. Moreover, numerical simulations are performed to analyze the rol of the intrinsic properties of neurons in their synchronization. It is shown that the same properties that determine the subthreshold behavior are relevant to improve synchronization between neurons too. Finally, this thesis contributes not only with new models and answers, but with new questions, which should be studied using experimental models as well. This thesis applies several tools used for electrical engineering (frequency response of systems, cable equation, Markov chains, evolutionary algorithms, etc.) to model and analyze a biological system. Among the contributions of this thesis are: the complete modeling of the sodium currents and other ionic current (and its modulation); the explanation preference subthreshold frequency transfer between neuronfor example and its coupling. Some preliminary results of this work have been presented at international conferences.El objetivo de esta tesis es analizar el rol de las propiedades intrĂnsecas de las neuronas en la comunicaciĂłn a travĂ©s de sinapsis elĂ©ctricas. Las neuronas del nervio trigeminal del mesencĂ©falo constituyen un excelente modelo experimental para estudiar la comunicaciĂłn entre neuronas, debido a su fácil acceso experimental y su sencilla morfologĂa. Sin embargo, el análisis de neuronas reales está limitado por restricciones experimentales que impiden explorar todos los aspectos del modelo. En el marco de esta tesis, se construye un modelo matemático basado en registros electrofisiolĂłgicos realizados por Sebastián Curti en la Facultad de Medicina de la Universidad de la RepĂşblica. El modelo consiste en un sistema de ecuaciones diferenciales, que puede ser representado por un circuito elĂ©ctrico con componentes no lineales. Algunas de las ecuaciones diferenciales son obtenidas de bibliografĂa y se realizan algunos ajustes menores de parámetros. Por otro lado, durante la tesis evaluamos que se necesitaba más informaciĂłn para reproducir algunas de las caracterĂsticas más importantes del comportamientos de las neuronas, como la duraciĂłn del potencial de acciĂłn. Por eso, se debieron realizar nuevos registros experimentales, que permitieron refinar el modelo. El modelo permite evaluar la respuesta de la neurona ante diferentes estĂmulos (corrientes o voltajes impuestos por un electrodo), posibilitando nuevos “experimentos” que no son posibles en un laboratorio. Se analizan diversas alternativas de modelado (variando corrientes iĂłnicas y morfologĂa) usando informaciĂłn experimental para validarlos. Luego, el modelo es utilizado para entender algunas caracterĂsticas inusuales de la comunicaciĂłn entre neuronas. En primer lugar, se estudia la transferencia subumbral (i.e.: sin potenciales de acciĂłn) entre neuronas acopladas por sinapsis elĂ©ctricas. Se utiliza un modelo reducido, que es linealizado para obtener una expresiĂłn analĂtica de la transferencia, cuyo comportamiento es coherente con los resultados experimentales. Asimismo, se realizan simulaciones numĂ©ricas para analizar el rol en la sincronizaciĂłn de las propiedades intrĂnsecas de las neuronas. Se muestra que las mismas propiedades que determinan el comportamiento subumbral son relevantes para mejorar la sincronizaciĂłn entre neuronas. Finalmente, esta tesis no sĂłlo contribuye con nuevos modelos y respuestas, sino con nuevas preguntas, que deberán ser estudiadas usando modelos experimentales tambiĂ©n. Esta tesis hace uso de diversas herramientas utilizadas por la ingenierĂa elĂ©ctrica (comportamiento en frecuencia de sistemas, ecuaciĂłn del cable, cadenas de Markov, algoritmos evolutivos, etc) para modelar y analizar un sistema biolĂłgico. Se realizan diversos aportes, por ejemplo: modelado completo de las corrientes de sodio, asĂ como de la modulaciĂłn de otra corriente; explicaciĂłn de la preferencia en frecuencia de la transferencia subumbral entre neuronas; estudio de la sincronizaciĂłn en funciĂłn de las propiedades de los osciladores y de su acople. Algunos resultados preliminares de este trabajo han sido presentados en congresos internacionales
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