Optimal enforcement policy and firms' emissions and compliance with environmental taxes

In a market where firms with different characteristics decide upon both the level of emissions and their reports, we study the optimal audit policy for an enforcement agency whose objective is to minimize the level of emissions. We show that it is optimal to devote the resources primarily to the easiest-to-monitor firms and to those firms that value pollution the less. Moreover, unless the budget for monitoring is very large, there are always firms that do not comply with the environmental objective and others that do comply; but all of them evade the environmental taxes.

Distortion of wreath products in some finitely presented groups

"Vegeu el resum a l'inici del document del fitxer adjunt."

Sobre alguns ectoparasitos de roedores silvestres do município de caratinga, Minas Gerais, Brasil: II. Acarofauna

Os autores capturaram ácaros de roedores silvestres na região de Caratinga, Minas Gerais, Brasil, entre abril de 1976 e março de 1977. Foram capturados 169 roedores de 10 espécies e coletados 2.444 ácaros de 11 espécies. Eubrachylaelaps rotundus foi o ácaro predominante, sendo capturado principalmente em roedores do gênero Akodon. Vinte e três registros novos de hospedeiros são apresentados com Atricholaelaps guimaraesi aparecendo pela primeira vem em seis espécies de roedores.

Agroecologia periurbana a Sant Cugat: document base per a la redacció del Pla de Gestió i Desenvolupament del parc rural de la Torre Negra

El parc rural de la Torre Negra ha estat protegit recentment després de 15 anys de lluita ciutadana, gràcies a l’aprovació del Pla Especial de Protecció i Millora el 29 de juny del present any. A partir d’ara, s’obre un ampli ventall de possibilitats per a la seva gestió i desenvolupament. En aquest context és on es situa el present estudi, amb la finalitat de presentar unes línies estratègiques bàsiques per a iniciar l’activitat al parc. Una activitat que té en el punt de mira el desenvolupament rural de l’espai i la transformació social de la ciutadania.

Médecine de l'addiction: naissance d'une nouvelle discipline

Les addictions ont fortement consolidé leur place dans le champ de la médecine à la fin du 20e siècle parce que la certitude de leurs fondements neurobiologiques était désormais acquise et que les preuves de l'efficacité des stratégies de prévention et de traitement étaient suffisantes. La médecine de l'addiction couvre un champ très large de l'activité médicale allant de la prévention de l'usage à risque, en passant par le dépistage des formes peu sévères de dépendance au traitement des formes les plus graves, chroniques et invalidantes. Cette activité médicale prend place dans une grande diversité de lieux de soins, en médecine de premier recours, particulièrement dans les cabinets de médecine de famille, mais aussi aux urgences et en pédiatrie. La médecine de l'addiction est très présente en psychiatrie où ses formes sont souvent sévères. Malgré cela, aujourd'hui seul un patient sur dix touché par une problématique d'addiction est traité. C'est la raison pour laquelle la Suisse, comme c'est le cas aux Etats-Unis et aux Pays-Bas par exemple, doit se doter d'un système promouvant une médecine de l'addiction à «large spectre», permettant d'identifier et de traiter la grande diversité des troubles rencontrés dans les lieux de soins les plus touchés. En Suisse, les médecins sont actuellement insuffisamment préparés pour assumer ce rôle. C'est aux disciplines concernées de proposer des filières de formation. Cette stratégie contribuera à améliorer les compétences de l'ensemble du corps médical dans ce domaine, avec pour conséquence d'offrir au plus grand nombre de patients touchés par les addictions les traitements les plus efficaces

Class-size Reduction Policies and the Quality of Entering Teachers

State-wide class-size reduction (CSR) policies have typically failed to produce large achievement gains. One explanation is that the introduction of such policies forces schools to hire relatively low-quality teachers. This paper uses data from an anonymous state to explore whether teacher quality suff ered from the introduction of CSR. We find that it did, but not nearly enough to explain the small achievement effects of CSR. The combined fall in achievement due to hiring lower quality teachers and more inexperienced teachers is small relative to the unrealized gains. Furthermore, between-school diff erences in the quality of incoming teachers cannot explain the poor estimated CSR performance from previous quasi-experimental treatment-control comparisons.

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Developing a predictive understanding of subsurface flow and transport is complicated by the disparity of scales across which controlling hydrological properties and processes span. Conventional techniques for characterizing hydrogeological properties (such as pumping, slug, and flowmeter tests) typically rely on borehole access to the subsurface. Because their spatial extent is commonly limited to the vicinity near the wellbores, these methods often cannot provide sufficient information to describe key controls on subsurface flow and transport. The field of hydrogeophysics has evolved in recent years to explore the potential that geophysical methods hold for improving the quantification of subsurface properties and processes relevant for hydrological investigations. This chapter is intended to familiarize hydrogeologists and water-resource professionals with the state of the art as well as existing challenges associated with hydrogeophysics. We provide a review of the key components of hydrogeophysical studies, which include: geophysical methods commonly used for shallow subsurface characterization; petrophysical relationships used to link the geophysical properties to hydrological properties and state variables; and estimation or inversion methods used to integrate hydrological and geophysical measurements in a consistent manner. We demonstrate the use of these different geophysical methods, petrophysical relationships, and estimation approaches through several field-scale case studies. Among other applications, the case studies illustrate the use of hydrogeophysical approaches to quantify subsurface architecture that influence flow (such as hydrostratigraphy and preferential pathways); delineate anomalous subsurface fluid bodies (such as contaminant plumes); monitor hydrological processes (such as infiltration, freshwater-seawater interface dynamics, and flow through fractures); and estimate hydrological properties (such as hydraulic conductivity) and state variables (such as water content). The case studies have been chosen to illustrate how hydrogeophysical approaches can yield insights about complex subsurface hydrological processes, provide input that improves flow and transport predictions, and provide quantitative information over field-relevant spatial scales. The chapter concludes by describing existing hydrogeophysical challenges and associated research needs. In particular, we identify the area of quantitative watershed hydrogeophysics as a frontier area, where significant effort is required to advance the estimation of hydrological properties and processes (and their uncertainties) over spatial scales relevant to the management of water resources and contaminants.

Paper del sulfur d'hidrogen com a neurotransmissor a nivell dels sistema nerviòs entèric

Al llarg dels últims anys l’òxid nítric (NO) i el monòxid de carboni (CO) han estat investigats com dos neurotransmissors gasosos del tracte gastrointestinal. Algunes dades demostren que el sulfur d’hidrogen (H2S) podria ser el tercer neurotransmissor gasos a nivell central i perifèric. Objectiu: valorar si el H2S compleix els requisits per ser considerat com el tercer neurotransmissor gasos a nivell del sistema nerviós entèric. Mètodes: la motilitat espontània de preparacions de múscul llis circular de mostres de còlon sigma humà i còlon mig de rata es van determinar in vitro mitjançant la tècnica de banys d’òrgans. El hidrogensulfur de sodi (NaHS) va ser utilitzat com donador de H2S. Resultats: 1- El NaHS va inhibir de forma concentració depenent la motilitat espontània en presència de bloqueig neural amb Tetrodotoxina (TTX 1 μM) (IC50 101±18 μM rata n=10; 329±86 μM humà n=18). 2- Aquesta relaxació es va veure reduïda per ODQ 10 μM, un inhibidor de la guanilat ciclasa, en còlon mig de rata (n=5). En humà a més de ser reduïda per ODQ 10μM (n=6), també ho va ser per SQ 22,536 100 μM (n=10), un inhibidor de l’adenilat ciclasa, i per L-NNA 1 mM (n=8), un inhibidor de la sintesi de NO. 3- En còlon de rata la incubació amb D,L-Propargilglicina 2 mM (PAG), un inhibidor de la síntesi de H2S, va incrementar la motilitat tant en situació control (10,05±2,06 vs 17,46±3,37 g•min-1 AUC, P&0,001, n=10) com en presència de TTX 1μM (14,45±7,28 vs 21,67±10,05 g•min-1 AUC, P&0,01, n=7). Conclusió: el H2S compleix part dels criteris per ser considerat un neurotransmissor gasos inhibitori en el tracte gastrointestinal: la inhibició de la seva síntesi incrementa la motilitat intestinal i la seva addició exògena produeix relaxació de la musculatura llisa intestinal.

On the Sources of Uncertainty in Exchange Rate Predictability

We analyse the role of time-variation in coefficients and other sources of uncertainty in exchange rate forecasting regressions. Our techniques incorporate the notion that the relevant set of predictors and their corresponding weights, change over time. We find that predictive models which allow for sudden rather than smooth, changes in coefficients significantly beat the random walk benchmark in out-of-sample forecasting exercise. Using innovative variance decomposition scheme, we identify uncertainty in coefficients' estimation and uncertainty about the precise degree of coefficients' variability, as the main factors hindering models' forecasting performance. The uncertainty regarding the choice of the predictor is small.

Health care utilization among immigrants and native-born populations in 11 European countries. Results from the Survey of Health, Ageing and Retirement in Europe

Objective: This study examines health care utilization of immigrants relative to the native-born populations aged 50 years and older in eleven European countries. Methods. We analyzed data from the Survey of Health Aging and Retirement in Europe (SHARE) from 2004 for a sample of 27,444 individuals in 11 European countries. Negative Binomial regression was conducted to examine the difference in number of doctor visits, visits to General Practitioners (GPs), and hospital stays between immigrants and the native-born individuals. Results: We find evidence those immigrants above age 50 use health services on average more than the native-born populations with the same characteristics. Our models show immigrants have between 6% and 27% more expected visits to the doctor, GP or hospital stays when compared to native-born populations in a number of European countries. Discussion: Elderly immigrant populations might be using health services more intensively due to cultural reasons.

The murine model of infection with Leishmania major and its importance for the deciphering of mechanisms underlying differences in Th cell differentiation in mice from different genetic backgrounds.

Mice from the majority of inbred strains are resistant to infection by Leishmania major, an obligate intracellular protozoan parasite of macrophages in the mammalian host. In contrast, mice from BALB strains are unable to control infection and develop progressive disease. In this model of infection, genetically determined resistance and susceptibility have been clearly shown to result from the appearance of parasite-specific CD4+ T helper 1 or T helper 2 cells, respectively. This murine model of infection is considered as one of the best experimental systems for the study of the mechanisms operating in vivo at the initiation of polarised T helper 1 and T helper 2 cell maturation. Among the several factors influencing Th cell development, cytokines themselves critically regulate this process. The results accumulated during the last years have clarified some aspects of the role played by cytokines in Th cell differentiation. They are providing critical information that may ultimately lead to the rational devise of means by which to tailor immune responses to the effector functions that are most efficient in preventing and/or controlling infections with pathogens.

Heterologous desensitization of the glucagon-like peptide-1 receptor by phorbol esters requires phosphorylation of the cytoplasmic tail at four different sites.

Glucagon-like peptide-1 stimulates glucose-induced insulin secretion by binding to a specific G protein-coupled receptor that activates the adenylyl cyclase pathway. We previously demonstrated that heterologous desensitization of the receptor by protein kinase C correlated with phosphorylation in a 33-amino acid-long segment of the receptor carboxyl-terminal cytoplasmic tail. Here, we determined that the in vivo sites of phosphorylation are four serine doublets present at positions 431/432, 441/442, 444/445, and 451/452. In vitro phosphorylation of fusion proteins containing mutant receptor C-tails, however, indicated that whereas serines at position 431/432 were good substrates for protein kinase C (PKC), serines 444/445 and 451/452 were poor substrates, and serines 441/442 were not substrates. In addition, serine 416 was phosphorylated on fusion protein but not in intact cells. This indicated that in vivo a different PKC isoform or a PKC-activated kinase may phosphorylate the receptor. The role of phosphorylation on receptor desensitization was assessed using receptor mutants expressed in COS cells or Chinese hamster lung fibroblasts. Mutation of any single serine doublet to alanines reduced the extent of phorbol 12-myristate 13-acetate-induced desensitization, whereas substitution of any combination of two serine doublets suppressed it. Our data thus show that the glucagon-like peptide-1 receptor can be phosphorylated in response to phorbol 12-myristate 13-acetate on four different sites within the cytoplasmic tail. Furthermore, phosphorylation of at least three sites was required for desensitization, although maximal desensitization was only achieved when all four sites were phosphorylated.