Firm Size and Short-Term Dynamics in Aggregate Entry and Exit

Much of the research on industry dynamics focuses on the interdependence between the sectorial rates of entry and exit. This paper argues that the size of firms and the reaction-adjustment period are important conditions missed in this literature. I illustrate the effects of this omission using data from the Spanish manufacturing industries between 1994 and 2001. Estimates from systems of equations models provide evidence of a conical revolving door phenomenon and of partial adjustments in the replacement-displacement of large firms. KEYWORDS: aggregation, industry dynamics, panel data, symmetry, simultaneity. JEL CLASSIFICATION: C33, C52, L60, L11

Internship report: improving asymmetric term extraction from bilingual text

Estudi elaborat a partir d’una estada a Xerox Research Centre Europe a Grenoble, França,entre juny i desembre del 2006. El projecte tradueïx termes tècnics anglesos a noruec. És asimètric perquè no tenim recursos lingüístics per a la llengua noruega, però solament per a l'anglès. S’ha desenvolupat i posat en pràctica mètodes que comprovaven contigüitat ("local reordering" i permutació selectiva) per a millorar el funcionament d’una eina anterior. Contigüitat és quan una paraula es traduïx en paraules múltiples, aquestes paraules han de ser adjacents en l'oració. A més, s’ha construït una taula de les operacions de recerca per als termes tècnics i s’ha integrat aquesta taula en un programa de demostració.

Numerical simulation of combined heat transfer phenomena (conduction, convection, and radiation). Application to he optimisation of thermal systems

Thermal systems interchanging heat and mass by conduction, convection, radiation (solar and thermal ) occur in many engineering applications like energy storage by solar collectors, window glazing in buildings, refrigeration of plastic moulds, air handling units etc. Often these thermal systems are composed of various elements for example a building with wall, windows, rooms, etc. It would be of particular interest to have a modular thermal system which is formed by connecting different modules for the elements, flexibility to use and change models for individual elements, add or remove elements without changing the entire code. A numerical approach to handle the heat transfer and fluid flow in such systems helps in saving the full scale experiment time, cost and also aids optimisation of parameters of the system. In subsequent sections are presented a short summary of the work done until now on the orientation of the thesis in the field of numerical methods for heat transfer and fluid flow applications, the work in process and the future work.

Experimental investigation of transient natural convection cooling of high prandtl number fluid with variable viscosity

Report for the scientific sojourn at the James Cook University, Australia, between June to December 2007. Free convection in enclosed spaces is found widely in natural and industrial systems. It is a topic of primary interest because in many systems it provides the largest resistance to the heat transfer in comparison with other heat transfer modes. In such systems the convection is driven by a density gradient within the fluid, which, usually, is produced by a temperature difference between the fluid and surrounding walls. In the oil industry, the oil, which has High Prandtl, usually is stored and transported in large tanks at temperatures high enough to keep its viscosity and, thus the pumping requirements, to a reasonable level. A temperature difference between the fluid and the walls of the container may give rise to the unsteady buoyancy force and hence the unsteady natural convection. In the initial period of cooling the natural convection regime dominates over the conduction contribution. As the oil cools down it typically becomes more viscous and this increase of viscosity inhibits the convection. At this point the oil viscosity becomes very large and unloading of the tank becomes very difficult. For this reason it is of primary interest to be able to predict the cooling rate of the oil. The general objective of this work is to develop and validate a simulation tool able to predict the cooling rates of high Prandtl fluid considering the variable viscosity effects.

Prediction of the economic cost of individual long-term care in the Spanish population

Pensions together with savings and investments during active life are key elements of retirement planning. Motivation for personal choices about the standard of living, bequest and the replacement ratio of pension with respect to last salary income must be considered. This research contributes to the financial planning by helping to quantify long-term care economic needs. We estimate life expectancy from retirement age onwards. The economic cost of care per unit of service is linked to the expected time of needed care and the intensity of required services. The expected individual cost of long-term care from an onset of dependence is estimated separately for men and women. Assumptions on the mortality of the dependent people compared to the general population are introduced. Parameters defining eligibility for various forms of coverage by the universal public social care of the welfare system are addressed. The impact of the intensity of social services on individual predictions is assessed, and a partial coverage by standard private insurance products is also explored. Data were collected by the Spanish Institute of Statistics in two surveys conducted on the general Spanish population in 1999 and in 2008. Official mortality records and life table trends were used to create realistic scenarios for longevity. We find empirical evidence that the public long-term care system in Spain effectively mitigates the risk of incurring huge lifetime costs. We also find that the most vulnerable categories are citizens with moderate disabilities that do not qualify to obtain public social care support. In the Spanish case, the trends between 1999 and 2008 need to be further explored.

Longer-term impacts of mentoring, educational services, and incentives to learn: evidence from a randomized trial in the United States

This paper is the first to use a randomized trial in the US to analyze the short- and long-term educational and employment impacts of an afterschool program that offered disadvantaged high-school youth: mentoring, educational services, and financial rewards with the objective to improve high-school graduation and postsecondary schooling enrollment. The short-term hefty beneficial average impacts quickly faded away. Heterogeneity matters. While encouraging results are found for younger youth, and when the program is implemented in relatively small communities of 9th graders; detrimental longlived outcomes are found for males, and when case managers are partially compensated by incentive payments and students receive more regular reminders of incentives.

Mentoring, educational services, and economic incentives longer-term evidence on risky behaviors from a randomized trial

This paper is the first to use a randomized trial in the US to analyze the short- and long- term impacts of an afterschool program that offered disadvantaged high-school youth: mentoring, educational services, and financial rewards to attend program activities, complete high-school and enroll in post-secondary education on youths' engagement in risky behaviors, such as substance abuse, criminal activity, and teenage childbearing. Outcomes were measured at three different points in time, when youths were in their late-teens, and when they were in their early- and their latetwenties. Overall the program was unsuccessful at reducing risky behaviors. Heterogeneity matters in that perverse effects are concentrated among certain subgroups, such as males, older youths, and youths from sites where youths received higher amount of stipends. We claim that this evidence is consistent with different models of youths' behavioral response to economic incentives. In addition, beneficial effects found in those sites in which QOP youths represented a large fraction of the entering class of 9th graders provides hope for these type of programs when operated in small communities and supports the hypothesis of peer effects.

Stabilized Petrov-Galerkin methods for the convection-diffusion-reaction and the Helmholtz equations

We present two new stabilized high-resolution numerical methods for the convection–diffusion–reaction (CDR) and the Helmholtz equations respectively. The work embarks upon a priori analysis of some consistency recovery procedures for some stabilization methods belonging to the Petrov–Galerkin framework. It was found that the use of some standard practices (e.g. M-Matrices theory) for the design of essentially non-oscillatory numerical methods is not feasible when consistency recovery methods are employed. Hence, with respect to convective stabilization, such recovery methods are not preferred. Next, we present the design of a high-resolution Petrov–Galerkin (HRPG) method for the 1D CDR problem. The problem is studied from a fresh point of view, including practical implications on the formulation of the maximum principle, M-Matrices theory, monotonicity and total variation diminishing (TVD) finite volume schemes. The current method is next in line to earlier methods that may be viewed as an upwinding plus a discontinuity-capturing operator. Finally, some remarks are made on the extension of the HRPG method to multidimensions. Next, we present a new numerical scheme for the Helmholtz equation resulting in quasi-exact solutions. The focus is on the approximation of the solution to the Helmholtz equation in the interior of the domain using compact stencils. Piecewise linear/bilinear polynomial interpolation are considered on a structured mesh/grid. The only a priori requirement is to provide a mesh/grid resolution of at least eight elements per wavelength. No stabilization parameters are involved in the definition of the scheme. The scheme consists of taking the average of the equation stencils obtained by the standard Galerkin finite element method and the classical finite difference method. Dispersion analysis in 1D and 2D illustrate the quasi-exact properties of this scheme. Finally, some remarks are made on the extension of the scheme to unstructured meshes by designing a method within the Petrov–Galerkin framework.

Optimal coexistence of long-term and short-term contracts in labor Markets

We consider a market where firms hire workers to run their projects and such projects differ in profitability. At any period, each firm needs two workers to successfully run its project: a junior agent, with no specific skills, and a senior worker, whose effort is not verifiable. Senior workers differ in ability and their competence is revealed after they have worked as juniors in the market. We study the length of the contractual relationships between firms and workers in an environment where the matching between firms and workers is the result of market interaction. We show that, despite in a one-firm-one-worker set-up long-term contracts are the optimal choice for firms, market forces often induce firms to use short-term contracts. Unless the market only consists of firms with very profitable projects, firms operating highly profitable projects offer short-term contracts to ensure the service of high-ability workers and those with less lucrative projects also use short-term contracts to save on the junior workers' wage. Intermediate firms may (or may not) hire workers through long-term contracts.

Long-term azithromycin therapy in patients with severe chronic obstructive pulmonary disease and repeated pulmonary exacerbations

L’objectiu es determinar si el tractament amb azitromicina a llarg termini redueix la freqüència d’exacerbacions respiratòries en pacients amb malaltia pulmonar obstructiva crònica (MPOC) greu. Estudi retrospectiu observacional que avalua els beneficis clínics del tractament amb azitromicina a llarg termini (500 mg per via oral tres vegades per setmana) durant 12 mesos en pacients amb MPOC greu amb un mínim de 4 exacerbacions agudes (EAMPOC) per any o colonitzats per Pseudomonas aeruginosa. Es comparen amb els 12 mesos previs a l’introducció de l’azitromicina: nombre de EAMPOC, hospitalitzacions i dies d'estada hospitalària. L’azitromicina a llarg termini s’associa a una reducció significativa de EAMPOC, hospitalitzacions i dies d’estada hospitalària en pacients amb EPOC greu independentment de la colonització basal.

What do academic libraries have to do with Open Educational Resources? Theme : Long term sustainability of open education projects first steps to start up

This paper will discuss the possible roles of academic libraries in promoting, supporting, and sustaining institutional Open Educational Resource initiatives. It will note areas in which libraries or librarians have skills and knowledge that intersect with some of the needs of academic staff and students as they use and release OERs. It will also present the results of a brief survey of the views of some OER initiatives on the current and potential role of academic libraries.

Time-series regression models to study the short-term effects of environmental factors on health

Time series regression models are especially suitable in epidemiology for evaluating short-term effects of time-varying exposures on health. The problem is that potential for confounding in time series regression is very high. Thus, it is important that trend and seasonality are properly accounted for. Our paper reviews the statistical models commonly used in time-series regression methods, specially allowing for serial correlation, make them potentially useful for selected epidemiological purposes. In particular, we discuss the use of time-series regression for counts using a wide range Generalised Linear Models as well as Generalised Additive Models. In addition, recently critical points in using statistical software for GAM were stressed, and reanalyses of time series data on air pollution and health were performed in order to update already published. Applications are offered through an example on the relationship between asthma emergency admissions and photochemical air pollutants

Mutigrid preconditioner for nonconforming discretization of elliptic problems with jump coefficients

In this paper, we present a multigrid preconditioner for solving the linear system arising from the piecewise linear nonconforming Crouzeix-Raviart discretization of second order elliptic problems with jump coe fficients. The preconditioner uses the standard conforming subspaces as coarse spaces. Numerical tests show both robustness with respect to the jump in the coe fficient and near-optimality with respect to the number of degrees of freedom.

Long-term effectiveness of first-line antiretroviral theraphy in a cohort of HIV-1 infected patients.

Eligibility criteria might explain differences in viral response to combined antiretroviral treatment (cART) between clinical trials and routine care setting. Prospective analysis including HIV-1 infected patients starting cART between January 2004 and December 2009, at Hospital Universitari Vall d’Hebron. Effectiveness evaluated as time to treatment failure (TF), defined as virologic failure, loss to follow-up, death or treatment discontinuation whatever the reason other than switching. Effectiveness month 12, 24 and 36 was 82.9%, 78.5% and 76%, respectively. 57 (24.6%) patients presented TF, mainly due to intolerance or toxicity. Higher risk in patients starting before 2006 and those with protease inhibitor based regimen.

The Coherence of the European Foreign Policy: A Real Barrier or an Academic Term?

The purpose of the present study is to break down, in a general and summarised way, the concept of the coherence of the European Foreign Policy, in order to analyse its meaning, its scope and its implications. This focus on coherence will be specifically dealt with upon the analysis of the impact of this phenomenon on single institutional framework, as defined by the Treaty on European Union.