Fishing Technology and Optimal Distribution of Harvest Rates

In this paper we analyze the optimal management of a joint ownership fishery exploitation model where agents use different fishing gears. As opposed to other works, we consider a model in which the fishing technology affects resource's growth not only through the harvest function, but also through the natural growth rate of the resource. The main objective is to capture the evidence that some fishing gears alter the habitat of the resource, and may alter the natural growth rate of the resource. The main result we obtain is that, when the natural growth of the resource is altered by the fishing technology, the optimal stock is not independent of how harvest quotas are distributed among the agents. Thus, in this context, a fishing policy that determines, first, the optimum stock and, secondly, decides on how to distribute the harvest among the different agents will not be efficient.fisheries regulation, fishing gear's selectivity, sharing of quotas

Evolution and relationships of the conifer seed cone telemachus: Evidence from the triassic of antarctica

The seed cone Telemachus is known from several Triassic localities in Gondwana. New specimens from two localities in Antarctica provide additional information about the type species, Telemachus elongatus, based on details of morphology and anatomy revealed by using a modified transfer technique on the compressed plants. Seed cones of T. elongatus are up to 6.0 cm long and characterized by conspicuous, elongate bracts. A second Antarctic species, described here as Telemachus antarcticus, is segregated, based on a shorter bract and differences in cone size. Newly recognized features of the genus include the shape, size, and disposition of the ovules; vascularization of the ovuliferous complex; and scale and bract histology. As a result of this new information, it is now possible to compare Telemachus with the permineralized Middle Triassic conifer seed cone Parasciadopitys from the Central Transantarctic Mountains. The similarities between the two genera make it possible to relate organs in different preservational modes and to develop a more complete concept for this widely distributed Gondwana conifer. Placing the Telemachus plant within a phylogenetic context makes it possible to evaluate the relationship with other so-called transitional conifers, an informal group that has been interpreted as intermediate between Paleozoic and modern conifers.Fil: Escapa, Ignacio Hernán. University of Kansas; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Decombeix, Anne-Laure. University of Kansas; Estados UnidosFil: Taylor, Edith L.. University of Kansas; Estados UnidosFil: Taylor, Thomas N.. University of Kansas; Estados Unido

International and Intergenerational Dimensions of Climate Change: North-South Cooperation in an Overlapping Generations Framework

Global environmental problems such as climate change have both an international and an intertemporal dimension. Recently, some papers have used an overlapping generations framework to analyze the climate change problem taking into account jointly the issues of intergenerational equity and intertemporal efficiency but without considering the international aspect of the problem. In this paper, we extend such approach by considering an overlapping generations model of climate-economy interactions where the world is split into two regions: North and South. We resort to numerical simulations of the calibrated model to analyze the effect of cooperation over economic and climate variables under two different scenarios: long-lived and short-lived governments. The main aim of our analysis is to test numrically whether John and Pecchenino´s (1997) theoretical result, which states that international agreements with transfers that lack an intergenerational perspective could actually harm the environment, applies low us to conclude that when we consider short lived governments: (1) the lack of cooperation always leads to higher environmental degradation, (2) the higher the welfare weight attached to the North under cooperation, the lower the environmental degradation in the long run, and (3) some cooperative scenarios may lead in the short run to higher environmental degradation than what it would arise in the non cooperative scenario.international environmental agreements, intergenerational externality, climate change

Phylogenetic Analysis of Araucariaceae: Integrating Molecules, Morphology, and Fossils

Premise of research: Phylogenetic relationships of Araucariaceae (Coniferophyta, Araucariales) are revised on the basis of the first combined data matrix for the family. Methodology: Taxon sampling includes 39 ingroup species (31 extant, 8 fossils) and outgroup species of all the remaining conifer families. Five fossil Araucaria species, one species of the genus Araucarites, and two species of the extinct genera Wairarapaia and Emwadea were included in the analyses. Character sampling includes 23 genomic regions (19 plastid, 2 nuclear, and 2 mitochondrial) and 62 morphological characters (52 discrete and 10 continuous). The phylogenetic analyses were conducted with equally weighted parsimony. Additionally, several analyses under different taxon- and gene-sampling regimes were analyzed for identifying the causes of the long-lasting controversies in the interrelationships of the three extant genera of Araucariaceeae. Pivotal results: Monophyletic Araucariaceae is the sister group of Podocarpaceae, forming the order Araucariales. Monophyly of Araucaria and Agathis is also strongly supported by the data. The results of both molecular and combined analyses indicate that Wollemia and Agathis form a clade (=agathioid clade) sister to Araucaria. Within Araucaria, the analyses support the monophyly of the four currently recognized sections: Araucaria, Bunya, Intermedia, and Eutacta. Results support the monophyly of living and fossil Araucaria (including Araucarites), whereas the remaining extinct genera are placed as the stem of the agathioid clade. In terms of the sensitivity analyses performed, results suggest that inconsistencies among previous results would be related to ingroup sampling. Conclusions: By means of a combined phylogenetic analysis, we have been able to obtain a strongly supported and well-resolved phylogeny of Araucariaceae that includes both living species and fossil species for the group. This study shows the feasibility and usefulness of phylogenetic analyses that incorporate multiple sources of evidence (molecules/morphology, living/fossil species, discrete/continuous characters).Fil: Escapa, Ignacio Hernan. Museo Paleontológico Egidio Feruglio; ArgentinaFil: Catalano, Santiago Andres. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Instituto Superior de Entomología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tucumán; Argentin

Mares sobrecarregades. Factors que causen més dedicació de les mares en el treball domèstic

Utilitzant dades d'una mostra de 1.926 famílies formades per tots dos progenitors (pare i mare) i almenys un fill, s'ha examinat la relació que hi ha entre les característiques familiars (recursos, disponibilitat de temps, factors sociodemogràfics, característiques de les parelles i individuals) i les càrregues domèstiques de les mares a Catalunya. Aquesta mostra s'ha analitzat mitjançant regressions logístiques, per tal de trobar els perfils de les mares que són més propenses a dedicar una gran quantitat d'hores fent les tasques de la llar. A partir d'investigacions prèvies, s'hi plantegen diferents elements explicatius: la disponibilitat de temps, els recursos relatius, la situació professional i la influència de la participació domèstica de la parella. Els resultats confirmen una relació significativa entre els recursos relatius i la disponibilitat de temps de la mare pel que fa a la seva dedicació a la llar, la qual cosa dóna suport a les perspectives econòmiques de la distribució de les tasques de la llar i de la ideologia tradicional dels rols de gènere. No obstant això, els resultats també mostren que la presència d'homes cooperatius no només no implica una reducció de la jornada domèstica de les seves parelles, sinó que també augmenta la probabilitat d'una dedicació més gran de les mares. Això es deu al fet que la distribució de les tasques domèstiques en algunes llars respon més a una estratègia parental comuna, basada en la inversió de temps a la llar i en les relacions intergeneracionals, que no pas a una negociació basada en «el que faci l'un no cal que ho faci l'altre»

Solidaridad intergeneracional en época de crisis: ¿Mito o realidad?

La prolongación de la crisis económica ha multiplicado el interés por conocer los mecanismos que amortiguan las consecuencias de las situaciones de privación. Un relato extendido atribuye un papel central a los abuelos y abuelas que están acudiendo a socorrer con sus pensiones a sus hijos y nietos. Sin embargo, las evidencias de que disponemos sobre cambios en las estructuras y flujos de solidaridad intergeneracional son más bien escasas. El artículo explora la magnitud y naturaleza de las ayudas entre padres, madres, abuelos y abuelas, por un lado, e hijos, hijas, nietos y nietas, por otro, en España comparativamente a otros países europeos, centrándose en la corresidencia, el cuidado de nietos y las transferencias económicas inter vivos

La descripción automatizada de la correspondencia del conde de Gondomar.

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Sistema de comunicación de sistemas reconfigurables basado en PCI con sistemas de sobremesa

En este proyecto vamos a desarrollar un disco duro de estado sólido utilizando como soporte una tarjeta reconfigurable, o FPGA, con un chip SpartanII. Dada la limitación de lógica reconfigurable de la que disponemos vamos a desarrollar una memoria pequeña, de tan solo 2kbytes, pero que será suficiente para comprobar su funcionamiento y como ejercicio de comprensión y adquisición de experiencia en la elaboración de este tipo de componentes. La finalidad de este proyecto es cubrir todos los aspectos en el desarrollo de un componente periférico, desde su implementación en VHDL, su conexión y comunicación con el ordenador, hasta el acceso al mismo desde una aplicación de usuario. Nos hemos servido del puente Wishbone, obtenido de OpenCores, para realizar la comunicación con el PCI. En la FPGA implementamos la memoria, la configuración y protocolos de comunicación necesarios para conectar con la interfaz del Wishbone y comunicarnos con el PC a través del bus PCI. Para hacer posible que el sistema sea reconocible por el computador, y pueda interactuar con éste, desarrollamos un driver que encapsula la funcionalidad necesaria para instalar el dispositivo y realizar las transacciones a través del controlador DMA. Para tratar de obtener el mayor rendimiento, el traspaso de datos entre nuestro sistema y la computadora se realiza a través del DMA que nos permite escribir y leer directamente de la memoria RAM con mayor rapidez y, por tanto, liberar al procesador de la carga masiva de interrupciones que le supondría intervenir en las transferencias. Por último desarrollamos una aplicación de usuario que interactúa con los datos existentes en la memoria RAM y envía peticiones de lectura y escritura, por sectores, a nuestro dispositivo que realiza las transacciones en bloques de 512bytes. [ABSTRACT] By this project we are developing a solid state hard drive using a Field Programmable Gate Array, or FPGA, with a SpartanII chip. As the reconfigurable logic available is not enough we will rise a small memory of only 2kbytes but large enough to check its functionality and as understanding and experiencing exercise in development of such components. The purpose of this project is to cover all aspects in the development of a peripheral component, Its implementation in VHDL, its connection and communication with the computer, even the access through from software. We use the bridge Wishbone, obtained from OpenCores, to guarantee the connection to the PCI. Memory, configuration and connection protocols required by the Wishbone interface are implemented within the FPGA card to establish the communication with the PC via the PCI bus. To enable the system to be recognized by the computer, and interact with it, we developed a driver with all the required functionality to install the device and perform Transactions with the DMA controller. Data transfers between our system and the computer are granted by DMA increasing the performance of the device allowing us to read and write data directly to RAM memory faster and therefore, release the processor of being interrupted massively during transactions. Finally we developed user application software that interfaces with existing data within RAM memory and sends reading and writing requests to our device which performs transactions in 512bytes of block size