Comparative dietary analysis of Eurycheilichthys pantherinus and Pareiorhaphis hystrix: two Loricariidae species (Ostariophysi, Siluriformes) from Campos Sulinos biome, southern Brazil

This work was carried out in Marco river, São José dos Ausentes municipality, state of Rio Grande do Sul, southern Brazil. This region is located within the Campos Sulinos biome, an area of great biological importance due to its high diversity and endemism of fish. The feeding habits and food overlap between Eurycheilichthys pantherinus (Reis & Schaefer, 1992) (n=108) and Pareiorhaphis hystrix Pereira & Reis, 2002 (n=60) are described. Monthly samples were obtained between September 2000 and July 2001 with dipnets using the kick sampling technique. Stomach contents were analyzed based on frequency of occurrence, volumetric frequency and index of alimentary importance. The level of dietary specialization and food overlap were determined by the Levins measure and the Morisita index, respectively. Eurycheilichthys pantherinus fed mainly on immature aquatic insects, such as Dipterans and Ephemeropterans, and was classified as insectivore. Pareiorhaphis hystrix fed mainly on detritus associated with small amounts of aquatic insects, and was classified as detritivore. Species are clearly segregated by the use of food resources in Marco River. Their diets did not overlap and the differences observed in their feeding habits probably contribute for their coexistence.

The Analysis of interval censoring and double censoring via Markov chain Monte Carlo methods

L'Anàlisi de la supervivència s'utilitza en diferents camps per analitzar el temps transcorregut entre dos esdeveniments. El que distingeix l'anàlisi de la supervivència d'altres àrees de l'estadística és que les dades normalment estan censurades. La censura en un interval apareix quan l'esdeveniment final d'interès no és directament observable i només se sap que el temps de fallada està en un interval concret. Un esquema de censura més complex encara apareix quan tant el temps inicial com el temps final estan censurats en un interval. Aquesta situació s'anomena doble censura. En aquest article donem una descripció formal d'un mètode bayesà paramètric per a l'anàlisi de dades censurades en un interval i dades doblement censurades així com unes indicacions clares de la seva utilització o pràctica. La metodologia proposada s'ilustra amb dades d'una cohort de pacients hemofílics que es varen infectar amb el virus VIH a principis dels anys 1980's.

Contribuição para o estudo dos vetores de malaria no Brasil: Anopheles (Nyssorhynchus) Darlingi Root, em Campos, no Estado do Rio

Os autores relatam nesse trabalho observações colhidas no estudo da fauna anofélica da cidade de Campos, Estado do Rio. Assinalaram a presença das espécies A. arbitarsis, A. darlingi, A. triannulatus, A. oswaldoi, A. noroestensis, A. pessoai e A. intermedius. Em capturas domiciliares foram assinalados o darlingi, albitarsis e triannulatus, sendo êste último encontrado em pequeno número e nas casas em que animais domésticos cohabitavam com o homem, dormindo sob o mesmo teto. Como vetores locais encontraram o A. darlingi com 6.8% de oócistos e 4% de esporozoítos, o albitarsis com 2% de oócistos e as glândulas negativas para esporozoítos. Fizeram os A. A. um estudo sumário dos criadouros, assinalaram que as larvas do darlingi tanto podem ser encontradas nas grandes coleções hídricas, lagoas e canais, como em depressão do terreno e valas de drenagem a céu aberto. Fizeram ainda uma revisão bibliográfica em relação a capacidade vetora do darlingi e sôbre a ecologia das suas larvas.

Marcacao de caramujos Biomphalaria glabrata por radionuclideos para trabalhos em campos

Os autores marcam caramujos Biomphalaria glabrata com 75Se, 59Fe, 89Sr e 90Sr e através das curvas de captação, decaimento e distribuição dos radionuclídeos na concha/partes moles do caramujo, concluem que o radioestrõncio pode ser utilizado em experiências em campo sobre dispersão e dinâmica de população de caramujos.

Modeling sequencing errors by combining Hidden Markov models.

Among the largest resources for biological sequence data is the large amount of expressed sequence tags (ESTs) available in public and proprietary databases. ESTs provide information on transcripts but for technical reasons they often contain sequencing errors. Therefore, when analyzing EST sequences computationally, such errors must be taken into account. Earlier attempts to model error prone coding regions have shown good performance in detecting and predicting these while correcting sequencing errors using codon usage frequencies. In the research presented here, we improve the detection of translation start and stop sites by integrating a more complex mRNA model with codon usage bias based error correction into one hidden Markov model (HMM), thus generalizing this error correction approach to more complex HMMs. We show that our method maintains the performance in detecting coding sequences.

Which screening strategy using BMD measurements would be most cost effective for hip fracture prevention in elderly women? A decision analysis based on a Markov model.

INTRODUCTION: Hip fractures are responsible for excessive mortality, decreasing the 5-year survival rate by about 20%. From an economic perspective, they represent a major source of expense, with direct costs in hospitalization, rehabilitation, and institutionalization. The incidence rate sharply increases after the age of 70, but it can be reduced in women aged 70-80 years by therapeutic interventions. Recent analyses suggest that the most efficient strategy is to implement such interventions in women at the age of 70 years. As several guidelines recommend bone mineral density (BMD) screening of postmenopausal women with clinical risk factors, our objective was to assess the cost-effectiveness of two screening strategies applied to elderly women aged 70 years and older. METHODS: A cost-effectiveness analysis was performed using decision-tree analysis and a Markov model. Two alternative strategies, one measuring BMD of all women, and one measuring BMD only of those having at least one risk factor, were compared with the reference strategy "no screening". Cost-effectiveness ratios were measured as cost per year gained without hip fracture. Most probabilities were based on data observed in EPIDOS, SEMOF and OFELY cohorts. RESULTS: In this model, which is mostly based on observed data, the strategy "screen all" was more cost effective than "screen women at risk." For one woman screened at the age of 70 and followed for 10 years, the incremental (additional) cost-effectiveness ratio of these two strategies compared with the reference was 4,235 euros and 8,290 euros, respectively. CONCLUSION: The results of this model, under the assumptions described in the paper, suggest that in women aged 70-80 years, screening all women with dual-energy X-ray absorptiometry (DXA) would be more effective than no screening or screening only women with at least one risk factor. Cost-effectiveness studies based on decision-analysis trees maybe useful tools for helping decision makers, and further models based on different assumptions should be performed to improve the level of evidence on cost-effectiveness ratios of the usual screening strategies for osteoporosis.

Visor Web de les Normes subsidiàries i el cadastre de l’Ajuntament de Campos

El Visor Web de Cartografia de les Normes Subsidiàries i el Cadastre de Campos és un sistema, basat en la tecnologia WMS, que està desenvolupat emprant programari lliure i s’ha fet seguint els estàndards de l’OGC. El servidor és MapServer instal•lat sobre una plataforma Linux distribució openSUSE 10.1. La base de dades és PostgreSQL-PostGIS. S’ha emprat l’entorn Ka-Map que consisteix en una tecnologia que combina l’ús de la capacitat del servidor amb la de l’ordinador del client, cosa que fa que la visualització sigui més ràpida i ens permet que el mapa pugui emprar tota la pantalla de l’ordinador.

Realised and Optimal Monetary Policy Rules in an Estimated Markov-Switching DSGE Model of the United Kingdom

This paper investigates underlying changes in the UK economy over the past thirtyfive years using a small open economy DSGE model. Using Bayesian analysis, we find UK monetary policy, nominal price rigidity and exogenous shocks, are all subject to regime shifting. A model incorporating these changes is used to estimate the realised monetary policy and derive the optimal monetary policy for the UK. This allows us to assess the effectiveness of the realised policy in terms of stabilising economic fluctuations, and, in turn, provide an indication of whether there is room for monetary authorities to further improve their policies.

Adaptive Continuous time Markov Chain Approximation Model to General Jump-Diusions

We propose a non-equidistant Q rate matrix formula and an adaptive numerical algorithm for a continuous time Markov chain to approximate jump-diffusions with affine or non-affine functional specifications. Our approach also accommodates state-dependent jump intensity and jump distribution, a flexibility that is very hard to achieve with other numerical methods. The Kolmogorov-Smirnov test shows that the proposed Markov chain transition density converges to the one given by the likelihood expansion formula as in Ait-Sahalia (2008). We provide numerical examples for European stock option pricing in Black and Scholes (1973), Merton (1976) and Kou (2002).

Asset Prices, Business Cycles, and Markov-Perfect Fiscal Policy when Agents are Risk-Sensitive

We study a business cycle model in which a benevolent fiscal authority must determine the optimal provision of government services, while lacking credibility, lump-sum taxes, and the ability to bond finance deficits. Households and the fiscal authority have risk sensitive preferences. We find that outcomes are affected importantly by the household's risk sensitivity, but not by the fiscal authority's. Further, while household risk-sensitivity induces a strong precautionary saving motive, which raises capital and lowers the return on assets, its effects on fluctuations and the business cycle are generally small, although more pronounced for negative shocks. Holding the stochastic steady state constant, increases in household risk-sensitivity lower the risk-free rate and raise the return on equity, increasing the equity premium. Finally, although risk-sensitivity has little effect on the provision of government services, it does cause the fiscal authority to lower the income tax rate. An additional contribution of this paper is to present a method for computing Markov-perfect equilibria in models where private agents and the government are risk-sensitive decisionmakers.

Computing Markov-Perfect Optimal Policies in Business-Cycle Models

Time-inconsistency is an essential feature of many policy problems (Kydland and Prescott, 1977). This paper presents and compares three methods for computing Markov-perfect optimal policies in stochastic nonlinear business cycle models. The methods considered include value function iteration, generalized Euler-equations, and parameterized shadow prices. In the context of a business cycle model in which a scal authority chooses government spending and income taxation optimally, while lacking the ability to commit, we show that the solutions obtained using value function iteration and generalized Euler equations are somewhat more accurate than that obtained using parameterized shadow prices. Among these three methods, we show that value function iteration can be applied easily, even to environments that include a risk-sensitive scal authority and/or inequality constraints on government spending. We show that the risk-sensitive scal authority lowers government spending and income-taxation, reducing the disincentive households face to accumulate wealth.

Sistema de reconeixement de cares basat en múltiples vistes

En aquest projecte es proposa un algorisme de detecció de pell que introdueix el veïnatge a l’hora de classificar píxels. Partim d’un espai de color invariant après a partir de múltiples vistes i introduïm la influència del veïnatge mitjançant camps aleatoris de Markov. A partir dels experiments realitzats podem concloure que la inclusió del veïnatge en el procés de classificació de píxels millora significativament els resultats de detecció.

El Estado en los campos. La regulación del cultivo del arroz en la España del siglo XIX

El papel desempeñado por el Estado en la economía española del siglo XIX ha sido muy controvertido y, en general, ha recibido juicios negativos. Este artículo trata de evaluar la intervención pública en el ámbito de la regulación del cultivo del arroz. Justificada frente al paludismo, esta reglamentación encontró grandes dificultades para ser aplicada hasta que se consolidó el nuevo aparato estatal salido de la revolución liberal, a causa de las resistencias locales y las limitaciones administrativas. En la segunda mitad del siglo XIX, sin embargo, el Estado estableció una legislación que perviviría en el tiempo y fue ampliamente respetada. De ese modo el Estado mostró una cierta autonomía respecto a intereses sociales muy arraigados y materializó medidas que tenían un impacto sobre la mejora sanitaria de la población.