Estràtegies de gestió per al manteniment de la biodiversitat a la sabana brasilera: control d'especies exòtiques amb foc

Report for the scientific sojourn at the Instituto de Biociências, of the Universidade de Sao Paulo, Brazil, from 2007 to 2009. African exotic grasses, used as forage crops for cattle, found optimal conditions in Brazilian savannas for their spread. They established as invasive grasses in almost all conservation units, becoming a serius threat to native biote and to most ecological processes. Fire is a cyclical event in Brazilian savannas and can be used as a management tool for enhancing competitivity of native grasses and controlling exotic grasses. Seeking for alternatives for the management of these grasses, this study investigates the effect of recurrent burnings in different periods of the year (fire regimes) on: distribution patterns of exotic grasses and their associations wotih native grasses, the local edaphic characteristics, the nutrient pool of the aerial biomass of both native and exotic grasses, and soil seed banks. This project is held on the IBGE Ecological Reserve, in Brasília (Brazil), in an area destined specifically for research of fire effects on brazilian savannas. The project quantifies: aerial biomass of native and exotic grasses, soil seed bank of exotic grasses, nutrient pool in soil and also in grasses tissues. Spatial relationships for any association between species, as well as for nutrient pools in soil and in plant tissues will be established. A better understanding of these processes will provide useful tools for adopting specific policies on the management of exotic grasses in Brazilian savanna.

Estudio de la estructura y composición de carbonales (Acacia pennatula) en dos estadios de desarrollo. Diseño de protocolo para el seguimiento de la dinámica de la vegetación en el CIEA "El Limón", Estelí (Nicaragua)

Los carbonales son un tipo de bosque secundario originados por el abandono de un sistema de producción silvopastoril. Estos parches de bosque ocupan una superficie importante de la zona de amortiguamiento de la Reserva Natural del Tisey-La Estanzuela, área del bioma más amenazado del mundo, el Bosque Seco Tropical. La principal especie que compone esta comunidad vegetal es la Acacia pennatula, conocida comúnmente como carbón. Actualmente no hay muchos estudios sobre los carbonales, por lo que el presente proyecto pretende caracterizar la estructura y composición de la comunidad y describir algunos índices ecológicos básicos, en dos estadios diferentes. El análisis de los datos proporciona información de las principales diferencias en cuanto a estructura y composición que tienen lugar en los carbonales. La disminución natural de la densidad de individuos de A. pennatula con los años, parece tener un efecto positivo sobre la diversidad, composición y estructura de la comunidad. En base a estos datos, se ha diseñado un protocolo para realizar un estudio experimental de estas comunidades en el CIEA “El Limón”. En el protocolo, mediante diferentes tratamientos de tala en estadios tempranos, se obtendrán áreas de estudio que presenten un gradiente en la variable densidad de individuos de A. pennatula. El objetivo principal es describir y comparar la estructura, composición y dinámica del carbonal a lo largo del tiempo, y determinar que efecto tiene sobre la comunidad modificar esta variable. Los resultados obtenidos en el protocolo pueden utilizarse como base para desarrollar un plan de manejo para los carbonales que facilite la restauración del Bosque Tropical Seco y el aprovechamiento forestal.

Sistema de reservas hoteleras RESHOTEL

XXXTOUR és una empresa que té com a principal negoci fer d'intermediari per a les agències de viatge i els particulars que vulguin reservar places hoteleres, d'una banda, i per als establiments hotelers, de l'altra. Així, doncs, contracta aquestes places a uns proveïdors i les ven a aquests clients. En l'actualitat, els proveïdors comuniquen a XXXTOUR totes les dades referents a les places mitjançant documents impresos i per telèfon, i els treballadors de l'empresa les han d'introduir al sistema d'informació de l'empresa. Per mitjà del nou sistema, els proveïdors, a més de poder emprar la funcionalitat actual, podran accedir al portal d'XXXTOUR i introduir les seves pròpies dades. I quan rebin una petició de places les podran confirmar accedint al portal, de manera que el client tindrà les places sol·licitades molt més aviat, cosa que millora el servei.

Tecnologia .NET : Hotel SPA

Treball de Fi de Carrera sobre la tecnologia .NET de Microsoft. En aquest treball s'ha creat un servei WCF i una petita aplicació de consola per hostatjar-lo. Aquest servei utilitza unes classes de LINQ To SQL per accedir a la base de dades. L'aplicació HotelSpaWPF, creada amb WPF i XAML, consumeix el servei WCF per treballar amb la informació de que es disposa a la base de dades.L'aplicació d'escriptori HotelSpaWPF consta de dues parts, la part corresponent als clients de l'hotel, on podran consultar el serveis, activitats i recursos oferts així com fer peticions, inscripcions o reserves. La part d'administrador permet gestionar tota aquesta informació.

Monetary policy with signal extraction from the bond market

Monetary policy is conducted in an environment of uncertainty. This paper sets upa model where the central bank uses real-time data from the bond market togetherwith standard macroeconomic indicators to estimate the current state of theeconomy more efficiently, while taking into account that its own actions influencewhat it observes. The timeliness of bond market data allows for quicker responsesof monetary policy to disturbances compared to the case when the central bankhas to rely solely on collected aggregate data. The information content of theterm structure creates a link between the bond market and the macroeconomythat is novel to the literature. To quantify the importance of the bond market asa source of information, the model is estimated on data for the United Statesand Australia using Bayesian methods. The empirical exercise suggests that thereis some information in the US term structure that helps the Federal Reserve toidentify shocks to the economy on a timely basis. Australian bond prices seemto be less informative than their US counterparts, perhaps because Australia is arelatively small and open economy.

The daily market for funds in Europe: Mathematical appendix

This paper includes the derivations of the main expressions in the paper ``The Daily Market for Funds in Europe: Has Something Changed With the EMU?'' by G. Pérez Quirós and H. Rodríguez Mendizábal.

The daily market for funds in Europe: Has something changed with the EMU?

This paper presents evidence that the existence of deposit and lending facilities combined with an averaging provision for the reserve requirement are powerful tools to stabilize the overnight rate. We reach this conclusion by comparing the behavior of this rate in Germany before and after thestart of Stage III of the EMU. The analysis of the German experience is useful because it allows us to isolate the effects on the overnight rate of these particular instruments of monetary policy. To show that this outcome is a general conclusion and not a particular result of the German market, we develop a theoretical model of reserve management which isable to reproduce our empirical findings.

Experimental evidence that intra-specific competition in seagrass meadows reduces reproductive potential in the sea urchin Paracentrotus lividus (Lamarck)

To better understand the biological controls that regulate sea urchin dynamics, we studied the effects of potential inter- and intra-specific competition for food on several biological variables of the main sea urchin in the Mediterranean (Paracentrotus lividus). We carried out a caging experiment in which we manipulated sea urchin density (natural vs. high density) and herbivorous fish (Sarpa salpa) accessibility (free access vs. exclusion) in a Posidonia oceanica meadow. No evidence of competition between fish and urchins was detected. Neither density-dependent mortality nor changes in the somatic variables were found; however, we detected that intra-specific competition affected the reproductive potential of P. lividus. The gonad index of urchins at high population densities was ca. 30% lower than that of urchins at natural densities. As a spawning event had just occurred when urchins were collected, these differences probably reflect differences in reserve content, which may compromise the following reproductive period and decrease survival in the long term, as the gonads are also used as storage organs. For the time period studied, mortality rates appeared to be independent of local densities. The results indicate that a long-term negative feedback mechanism appears to take place in P. lividus in response to increased population density.

De la mano de Keynes: "A tract on monetary reform"

En Tract on Monetary Reform, John Maynard Keynes propuso utilizar la base monetaria y el coeficiente de reserva bancaria como variables instrumentales d¿una política monetaria que había sido considerada hasta entonces innecesaria. En este trabajo se intenta desvelar las primeras contribuciones de Keynes al progreso del análisis económico

De la mano de Keynes: "A tract on monetary reform"

En Tract on Monetary Reform, John Maynard Keynes propuso utilizar la base monetaria y el coeficiente de reserva bancaria como variables instrumentales d¿una política monetaria que había sido considerada hasta entonces innecesaria. En este trabajo se intenta desvelar las primeras contribuciones de Keynes al progreso del análisis económico

Multiple processes regulate long-term population dynamics of sea urchins on Mediterranean rocky reefs

We annually monitored the abundance and size structure of herbivorous sea urchin populations (Paracentrotus lividus and Arbacia lixula) inside and outside a marine reserve in the Northwestern Mediterranean on two distinct habitats (boulders and vertical walls) over a period of 20 years, with the aim of analyzing changes at different temporal scales in relation to biotic and abiotic drivers. P. lividus exhibited significant variability in density over time on boulder bottoms but not on vertical walls, and temporal trends were not significantly different between the protection levels. Differences in densities were caused primarily by variance in recruitment, which was less pronounced inside the MPA and was correlated with adult density, indicating density-dependent recruitment under high predation pressure, as well as some positive feedback mechanisms that may facilitate higher urchin abundances despite higher predator abundance. Populations within the reserve were less variable in abundance and did not exhibit the hyper-abundances observed outside the reserve, suggesting that predation effects maybe more subtle than simply lowering the numbers of urchins in reserves. A. lixula densities were an order of magnitude lower than P. lividus densities and varied within sites and over time on boulder bottoms but did not differ between protection levels. In December 2008, an exceptionally violent storm reduced sea urchin densities drastically (by 50% to 80%) on boulder substrates, resulting in the lowest values observed over the entire study period, which remained at that level for at least two years (up to the present). Our results also showed great variability in the biological and physical processes acting at different temporal scales. This study highlights the need for appropriate temporal scales for studies to fully understand ecosystem functioning, the concepts of which are fundamental to successful conservation and management.

Experimental evidence that intra-specific competition in seagrass meadows reduces reproductive potential in the sea urchin Paracentrotus lividus (Lamarck)

To better understand the biological controls that regulate sea urchin dynamics, we studied the effects of potential inter- and intra-specific competition for food on several biological variables of the main sea urchin in the Mediterranean (Paracentrotus lividus). We carried out a caging experiment in which we manipulated sea urchin density (natural vs. high density) and herbivorous fish (Sarpa salpa) accessibility (free access vs. exclusion) in a Posidonia oceanica meadow. No evidence of competition between fish and urchins was detected. Neither density-dependent mortality nor changes in the somatic variables were found; however, we detected that intra-specific competition affected the reproductive potential of P. lividus. The gonad index of urchins at high population densities was ca. 30% lower than that of urchins at natural densities. As a spawning event had just occurred when urchins were collected, these differences probably reflect differences in reserve content, which may compromise the following reproductive period and decrease survival in the long term, as the gonads are also used as storage organs. For the time period studied, mortality rates appeared to be independent of local densities. The results indicate that a long-term negative feedback mechanism appears to take place in P. lividus in response to increased population density.

Una reflexión sobre la impronta romana del 'beneficio de separación de patrimonios' en el Código Civil catalán

The roman institution of the separatio bonorum is a pretorian remedy that relies on the principle of equity, created as to protect the deceased creditors and/or legatees. It provides them a"benefit" in the case of selling the goods of the heir-deubtor, enabling them to separate and reserve for themselves that whole patrimonium, as to avoid that by the act of selling, the heirs creditors could go to it; and like this they maintain intact their guarantee, which relies on the whole goods and assets left by the deceased. The separation of patrimonies implied the existence of 2 different groups of goods: that of the heirs" and that one of the deceased, which are not the same in legal terms, in spite of having a common owner at this point, the heir. This institution was regulated in the 6th title of the 42nd book of the Digesto, and in the 72th title, 7th book of the Justinean Code, and its interest is really high due to its material complexity and its procedure. The aim of this work is to analyze the institution of the separatio bonorum in Roman Law, and its importance in the same figure, actually regulated in the 4th book of the Catalan civil code.

Multiple processes regulate long-term population dynamics of sea urchins on Mediterranean rocky reefs

We annually monitored the abundance and size structure of herbivorous sea urchin populations (Paracentrotus lividus and Arbacia lixula) inside and outside a marine reserve in the Northwestern Mediterranean on two distinct habitats (boulders and vertical walls) over a period of 20 years, with the aim of analyzing changes at different temporal scales in relation to biotic and abiotic drivers. P. lividus exhibited significant variability in density over time on boulder bottoms but not on vertical walls, and temporal trends were not significantly different between the protection levels. Differences in densities were caused primarily by variance in recruitment, which was less pronounced inside the MPA and was correlated with adult density, indicating density-dependent recruitment under high predation pressure, as well as some positive feedback mechanisms that may facilitate higher urchin abundances despite higher predator abundance. Populations within the reserve were less variable in abundance and did not exhibit the hyper-abundances observed outside the reserve, suggesting that predation effects maybe more subtle than simply lowering the numbers of urchins in reserves. A. lixula densities were an order of magnitude lower than P. lividus densities and varied within sites and over time on boulder bottoms but did not differ between protection levels. In December 2008, an exceptionally violent storm reduced sea urchin densities drastically (by 50% to 80%) on boulder substrates, resulting in the lowest values observed over the entire study period, which remained at that level for at least two years (up to the present). Our results also showed great variability in the biological and physical processes acting at different temporal scales. This study highlights the need for appropriate temporal scales for studies to fully understand ecosystem functioning, the concepts of which are fundamental to successful conservation and management.

Solvencia en un Reaseguro Finite Risk

One of the characteristics of the finite risk reinsurance is the existence of an found of experience, which is constituted by the premiums charged by the reinsurer, together with his financial incomes, and his objective is to finance the claims to be satisfied to the insurer in the specified period. The objective of this work is to design a model that allows us to determinate the reserve that the found of experience should have in every annual period in order to guarantee its dynamic solvency, taking into the experience of the claims of the reinsurer"s portfolio and of each insurance company.