3,879 research outputs found
Growth and size variation of Senegalese sole (Solea senegalensis)
Senegalese sole (Solea senegalensis) is a flatfish of high commercial importance in Southern Europe that has been a
promising species for diversifying Mediterranean aquaculture since early 1980's. It has failed to reach successful farming
development due to lack of full control over spawning, poor fry quality and high mortality during the weaning stage.
Furthermore, optimization of production has not been possible due to high heterogeneity in growth rates within cultured stocks
that result in high body size variance at harvest.
Among the several aspects needing wider knowledge in order to reach optimization of sole aquaculture, the ongrowing stage
from juveniles to the commercialization size has been overlooked until the last years. It includes the relationships between
individual growth and rearing parameters as stocking density, or the size composition of stocks. It is also important to evaluate
growth according to the feeding rhythms, offering feed at adequate times for this species. Not less important is to assess the
genetic variability of farmed stocks, and compare it to the wild populations, as a stepping stone to link genetic traits to the
performance of aquaculture stocks.
The aims of this thesis were to take an individual-based approach to growth, and growth sexual dimorphism, of Senegalese
sole reared at high and low densities, with different levels of initial size variation, and under different feeding strategies.
Moreover, the level of genetic variability of this species was compared between farmed and wild stocks through molecular
genetic markers, and their sibship relationships were also assessed.
Three experiments were conducted, involving a) rearing soles under high density (180% of bottom coverage) and low density
(60% of bottom coverage); b) rearing soles under the same high and low densities, but also under homogeneous or
heterogeneous initial size composition; c) rearing soles under a medium/high initial density (130% of bottom coverage) fed
either during nocturnal hours, similar to their natural feeding rhythms, or during daylight hours. Additionally, the genetic
variability of a farmed sample was compared to its wild donor population.
Stocking density affects growth of Senegalese sole in two ways. First, sudden and steep increases in density could lead to
poorer or no growth of fish until re-acclimatization to new high density conditions. Second, it seems that there is a sizedependent
component on how stocking density affects growth, with smaller fish (sub-adults) growth being suppressed by high
stocking density.
Size composition of reared Senegalese sole does not affect individual growth. Sole doesn¿t show aggressive behavior and
apparently, competition between individuals is low and size independent. Grading Senegalese sole does not guarantee the
improvement of growth, and if so, it would be in high density conditions.
Senegalese sole females grow faster than males, but after attaining certain body weight (between 40 and 80 g). It could be
hypothesized that sexual maturation may be involved in the onset of sexual growth dimorphism in this species.
Besides being an eminently nocturnal species, Senegalese sole fed during the light phase may yield specific growth rates and
feed conversion ratios that are comparable to those of fish fed during the dark phase, suggesting the feasibility of feeding
during normal business hours in commercial facilities.
There is a loss in genetic variability in a single generation of Senegalese sole rearing, as evidenced by lower values of
mitochondrial haplotypic diversity and nuclear diversity in the farmed sample compared with the wild donor population.
Comparing wild Atlantic and Mediterranean samples suggests a limited gene flow between the populations inhabiting these
basins. An accurate knowledge of the genetic composition of farmed stocks is essential both for maintaining the cultured
stocks and for potential future restocking purposes.
Castelldefels 17/El llenguado senegalès (Solea senegalensis) és un peix pla de gran importància comercial al sud d'Europa. El seu cultiu no està totalment desenvolupat, en part degut a l'alta heterogeneïtat en les taxes de creixement dins de les poblacions cultivades, que donen lloc a una alta dispersió de talles en arribar a la mida comercial. Els objectius de la tesi van ésser l'aproximació individual al creixement, i al dimorfisme sexual del creixement, del llenguado cultivat a altes i baixes densitats, amb diferents nivells de dispersió de talles inicial i sota diferents estratègies alimentàries. D'altra banda, el nivell de variabilitat genètica d'aquesta espècie es va comparar entre les poblacions de cultiu i salvatges a través de marcadors genètics moleculars, i es van avaluar les seves relacions de parentiu. Es van dur a terme tres experiments, implicant a) el cultiu de llenguado a alta densitat (180% de cobertura del fons del tanc) i baixa densitat (60% de cobertura); b) el cultiu de llenguado sota les mateixes densitats, però també sota condicions d'homogeneïtat o heterogeneïtat de talles inicials; c) cultiu de llenguado a densitat mitja/alta (130% de cobertura) alimentats durant les hores nocturnes, de manera semblant als seus ritmes alimentaris naturals, o durant les hores diürnes. Addicionalment, es va comparar la variabilitat genètica d'una mostra de cultiu amb la seva població salvatge donant. La densitat de cultiu afecta el creixement del llenguado senegalès de dues maneres. En primer lloc, els augments sobtats i pronunciats de la densitat podrien conduir a un creixement pobre o nul fins la re-aclimatació a les noves condicions d'alta densitat. En segon lloc, sembla que hi ha una component mida-dependent de com la densitat de cultiu afecta el creixement, amb els peixos més petits (sub-adults) experimentant una supressió del seu creixement degut a l'alta densitat. La composició de talles del llenguado senegalès de cultiu no afecta el creixement individual. El llenguado no mostra un comportament agressiu i, pel que sembla, la competència entre els individus és baixa i independent de la mida. La classificació de talles en el llenguado no garanteix la millora del seu creixement, i si és així, seria en condicions d'alta densitat. Les femelles de llenguado senegalès creixen més ràpid que els mascles, però després d'assolir cert pes corporal (entre 40 i 80 g). Es podria hipotetitzar que la maduració sexual pot estar implicada en l'aparició de dimorfisme sexual en el creixement d'aquesta espècie. A pesar de ser una espècie eminentment nocturna, el llenguado senegalès alimentat durant les hores de llum pot experimentar taxes de creixement específiques i ràtios de conversió de l'aliment que són comparables a les dels peixos alimentats durant les hores nocturnes, el que suggereix la viabilitat de l'alimentació durant les hores normals de treball a les instal·lacions comercials. Hi ha una pèrdua de la variabilitat genètica en una sola generació de cultiu de llenguado senegalès, com s'evidencia pels valors més baixos de diversitat haplotípica mitocondrial i diversitat nuclear de la mostra de cultiu en comparació amb la població salvatge donant. La comparació de mostres salvatges de l'Atlàntic i del Mediterrani suggereix un flux limitat de gens entre les poblacions que habiten en aquestes conques. Un coneixement exacte de la composició genètica de les poblacions de cria és essencial per al manteniment de les poblacions cultivades, i per a possibles programes de repoblació en el futur
La jurisprudencia internacional penal en materia de género
Jiménez Sánchez, Carolina. La dimensión de género en los tribunales penales internacionales. Thomson Reuters Aranzadi, 2016. 149 págs.
Introducción: Riesgos y amenazas para la seguridad humana
Cuando terminó la Segunda Guerra Mundial, el mundo asistía a un nuevo paradigma con el que construir la sociedad internacionales, desde parámetros más inclusivos. Nace la Organización de las Naciones Unidas con el objetivo de organizar una nueva sociedad, basada en el arreglo pacífico de las controversias y en la limitación del uso de la fuerza, como principales focos de interés
Recommended from our members
The quest for information retrieval on the semantic web
Semantic search has been one of the motivations of the Semantic Web since it was envisioned. We propose a model for the exploitation of ontology-based KBs to improve search over large document repositories. The retrieval model is based on an adaptation of the classic vector-space model, including an annotation weighting algorithm, and a ranking algorithm. Semantic search is combined with keyword-based search to achieve tolerance to KB incompleteness. Our proposal has been tested on corpora of significant size, showing promising results with respect to keyword-based search, and providing ground for further analysis and research
Study on the shear and punching-shear strength of reinforced concrete slabs subjected to point loads and in-plane tensile forces
Reinforced concrete members, especially when subjected to concentrated loads, can fail in shear. This is an undesirable and brittle failure mode preventing the structure from deforming and reaching higher load levels. It is therefore important to investigate and understand the nature of shear failures in RC beams and slabs, which are typically not provided with shear reinforcement. Despite the exhaustive research work carried out since the beginning of the XXth century, the shear behavior of reinforced concrete elements is still not fully clear. The complex kinematics and the different contribution of the widely accepted shear resisting actions, which depend, among other parameters, on the load level and the geometry of the specimens, are part of those uncertainties that have provoked the lack of consensus that currently exist around the shear problem in structural engineering.
In this context, this thesis focuses on the shear behavior of reinforced concrete slabs without shear reinforcement subjected to point loads. On the one hand, part of the work carried out during this investigation deals with shear in one way slabs supported on linear supports. Thanks to the experimental work conducted in the last two decades, a significant database of test results is now available, which has allowed to develop and verify a new mechanical model to predict the shear strength of RC one-way slabs without shear reinforcement. It takes into account a significant number of variables involved in the phenomenon and is applicable to is applicable to simply supported slabs, cantilever slabs and situations with partial restraint to the rotation. The model is divided into two sub-models. One for loads applied close to supports, where the direct transmission of the load to the support plays an important role in the shear strength and a second one for loads applied away from supports where the possibility of a shear failure is assumed to coexist with the possibility of a local punching failure.
On the other hand, the second part of the investigation deals with the shear behavior of reinforced concrete slabs subjected to the simultaneous action of in plane tensile stresses and out-of-plane point loads. This load case has not been exhaustively studied throughout the years, and in order to contribute to gain insight into this aspects of shear design, the mechanical model recently developed at UPC for the prediction of the punching-shear strength of two-way slabs has been extended to the case of simultaneous in-plane tensile forces. A set of experimental test for the validation of the model for the particular case of uniaxial in-plane tension is also presented. In addition to that, the particular case of one-way simply supported slabs subjected to transverse tensile stresses has also been experimentally studied. This is a seldom studied load case and the conducted set of test will help to understand the overall behavior of these elements under this particular loading condition.Los elementos de hormigón armado, especialmente cuando están sometidos a la acción de cargas puntuales, pueden alcanzar su resistencia última a esfuerzo cortante, lo cual limita su capacidad para deformarse y resistir valores de carga mayores. Este es un modo de fallo frágil y repentino, por lo que debe ser evitado. Así pues, es importante seguir investigando y comprender la naturaleza de la respuesta de vigas y losas de hormigón armado ante solicitaciones de este tipo, sobre todo cuando no están provistas de armadura de cortante. A pesar de la gran cantidad de campañas experimentales llevadas a cabo desde principios del siglo XX, el comportamiento a cortante y punzonamiento de los elementos estructurales de hormigón armado no está todavía del todo claro. La compleja cinemática y la diferente contribución de los mecanismos resistentes ampliamente aceptados, la cual depende, entre otros factores, del nivel de carga y de la geometría de los especímenes, son parte de esas incertidumbres que han provocado la falta de consenso que existe actualmente dentro del campo de la ingeniería estructural. En este contexto, esta tesis se centra en el comportamiento a cortante de losas de hormigón armado sin armadura de cortante sometidas a la acción de cargas puntuales. Por un lado, parte del trabajo realizado durante esta investigación está orientado al cortante en losas unidireccionales apoyadas sobre apoyos lineales. Gracias a todas las campañas experimentales realizadas en las últimas dos décadas, una significativa base de datos de resultados experimentales se encuentra disponible en la literatura, lo que ha permitido desarrollar y verificar un nuevo modelo mecánico para predecir la resistencia última a cortante de este tipo de elementos. Dicho modelo tiene en cuenta un número importante de variables involucradas en el fenómeno y es aplicable a losas simplemente apoyadas, en ménsula, y apoyadas en apoyos con restricción parcial al giro. El modelo se ha dividido en dos sub-modelos para facilitar su desarrollo. Uno para cargas aplicadas cerca de los apoyos, donde la transmisión directa de la carga al apoyo juega un papel importante, y un segundo para cargas aplicadas lejos de los apoyos, en donde se asume que la posibilidad del fallo por cortante coexiste con la posibilidad de un fallo local por punzonamiento. Por otro lado, la segunda parte de la investigación está focalizada en el comportamiento a cortante de losas de hormigón armado sometidas simultáneamente a la acción de cargas puntuales y tracciones en su plano. Este caso de carga no ha sido demasiado investigado a lo largo de las últimas décadas, y con la intención de contribuir a comprender esta compleja interacción, el modelo mecánico recientemente desarrollado en la UPC, para la predicción de la resistencia a punzonamiento en losas bidireccionales, ha sido extendido a este caso particular de cargas y validado con los resultados de campañas experimentales disponibles en la literatura y el conjunto de ensayos realizados como parte de esta investigación para el caso particular de tracciones unidireccionales. Adicionalmente, el efecto de las tracciones transversales en el plano en la resistencia a cortante de losas unidireccionales también ha sido estudiado experimentalmente. Esta combinación de cargas no ha sido apenas investigada y un nuevo grupo de ensayos experimentales puede contribuir a comprender el comportamiento global de este tipo de elementos ante este caso particular de carga.Postprint (published version
CORE: A tool for Collaborative Ontology Reuse and Evaluation
Also published online by CEUR Workshop Proceedings (CEUR-WS.org, ISSN 1613-0073) Proceedings of the Workshop on Social and Collaborative Construction of Structured Knowledge, CKC 2007In this work, we present an extension of CORE [8], a tool for
Collaborative Ontology Reuse and Evaluation. The system receives
an informal description of a specific semantic domain and
determines which ontologies from a repository are the most
appropriate to describe the given domain. For this task, the
environment is divided into three modules. The first component
receives the problem description as a set of terms, and allows the
user to refine and enlarge it using WordNet. The second module
applies multiple automatic criteria to evaluate the ontologies of the
repository, and determines which ones fit best the problem
description. A ranked list of ontologies is returned for each criterion,
and the lists are combined by means of rank fusion techniques.
Finally, the third component uses manual user evaluations in order
to incorporate a human, collaborative assessment of the ontologies.
The new version of the system incorporates several novelties, such
as its implementation as a web application; the incorporation of a
NLP module to manage the problem definitions; modifications on
the automatic ontology retrieval strategies; and a collaborative
framework to find potential relevant terms according to previous
user queries. Finally, we present some early experiments on
ontology retrieval and evaluation, showing the benefits of our system.This research was supported by the Spanish Ministry of Science
and Education (TIN2005-06885 and FPU program)
Stocking density and growth performance of Senegalese sole (Solea senegalensis). Preliminary results
Peer Reviewe
- …