Cycles saisonniers, reproduction et qualite des ovocytes chez Pecten maximus en rade de Brest

This work is part of the program, "recruitment determinism in scallops" initiated in 1992 by the "Contrat de Baie". The aim of this research was to explain interannual abundance fluctuations observed for Pecten maximus, in the Bay of Brest. To this end an analytical approach to the life cycle of the species was undertaken to determine its critical phases. A phase may be considered as "critical" if the mortality rate at its level varies from one year to the other. Using data from 1989 to 1994, a precise time-table of the "physiological year" of the scallop in the Bay of Brest was determined. Fecundity and gamete production kinetics were estimated from the annual variation in the weight indices of the gonad. In the laboratory, egg quality was estimated following stimulated spawning of newly caught individuals. The digestive activity was estimated by amylase activity measurements during a three year period. Spawning lasts 6 months in the Bay of Brest from March to October. Spawning, muscle and digestive gland growths, are intimately linked to phytoplancton blooms. Gonad production shows a maximum in April-May, and two relative minima in Match and November. These results, which provide detailed understanding of the adult's annual cycle in the Bay of Brest, will be used to interpret the relationship between the annual cycle and larval and post larval abundance and survival. Already, these results are being used to improve spat production in hatcheries.

ENGINEERING DIGITAL SHARING PLATFORM TO CREATE SOCIAL CONTAGION: EVIDENCE FROM LARGE SCALE RANDOMIZED FIELD EXPERIMENTS

Peer-to-peer information sharing has fundamentally changed customer decision-making process. Recent developments in information technologies have enabled digital sharing platforms to influence various granular aspects of the information sharing process. Despite the growing importance of digital information sharing, little research has examined the optimal design choices for a platform seeking to maximize returns from information sharing. My dissertation seeks to fill this gap. Specifically, I study novel interventions that can be implemented by the platform at different stages of the information sharing. In collaboration with a leading for-profit platform and a non-profit platform, I conduct three large-scale field experiments to causally identify the impact of these interventions on customers’ sharing behaviors as well as the sharing outcomes. The first essay examines whether and how a firm can enhance social contagion by simply varying the message shared by customers with their friends. Using a large randomized field experiment, I find that i) adding only information about the sender’s purchase status increases the likelihood of recipients’ purchase; ii) adding only information about referral reward increases recipients’ follow-up referrals; and iii) adding information about both the sender’s purchase as well as the referral rewards increases neither the likelihood of purchase nor follow-up referrals. I then discuss the underlying mechanisms. The second essay studies whether and how a firm can design unconditional incentive to engage customers who already reveal willingness to share. I conduct a field experiment to examine the impact of incentive design on sender’s purchase as well as further referral behavior. I find evidence that incentive structure has a significant, but interestingly opposing, impact on both outcomes. The results also provide insights about senders’ motives in sharing. The third essay examines whether and how a non-profit platform can use mobile messaging to leverage recipients’ social ties to encourage blood donation. I design a large field experiment to causally identify the impact of different types of information and incentives on donor’s self-donation and group donation behavior. My results show that non-profits can stimulate group effect and increase blood donation, but only with group reward. Such group reward works by motivating a different donor population. In summary, the findings from the three studies will offer valuable insights for platforms and social enterprises on how to engineer digital platforms to create social contagion. The rich data from randomized experiments and complementary sources (archive and survey) also allows me to test the underlying mechanism at work. In this way, my dissertation provides both managerial implication and theoretical contribution to the phenomenon of peer-to-peer information sharing.

Colheita de córneas no Hospital Fernando Fonseca: o potencial e a realidade

Introdução: A disponibilidade de córneas para transplante continua a ser um fator limitante na resposta terapêutica a muitos doentes com patologia de córnea. A operacionalização do programa de colheita e transplante de córneas no Hospital Prof. Doutor Fernando Fonseca, EPE (HFF) teve início em 2012 e desde então tem sido preocupação do núcleo de Coordenação Hospitalar de Doação (NCHD) a otimização do número de colheitas respeitando os padrões de qualidade definidos pela legislação. Metodologia: Os autores apresentam uma análise retrospetiva de todos os óbitos ocorridos no HFF no ano de 2014, aplicando os critérios de seleção demográficos e clínicos bem como as limitações operacionais próprias do hospital, de modo a verificar a eficiência do processo de colheita de córneas em coração parado. Resultados: Dos 1970 óbitos do HFF em 2014, 651 (33%) cumpriam o critério idade e 66 doentes foram elegíveis tendo em conta as contra-indicações clínicas e as limitações operacionais do HFF. Destes, 32 foram efectivados como colheitas. Das contra-indicações clínicas a neoplasia de órgão sólido (n=428), serologias positivas (n= 196),doença neurodegenerativa (n=132) e sepsis (n=117) foram as mais prevalentes considerando os óbitos entre os 12 e os 80 anos. Conclusões: Conclui-se que existe uma margem importante de melhoria no processo de referenciação e selecção de dadores. Um eventual ajuste nos critérios clínicos de inclusão, respeitando as guidelines internacionais poderiam possibilitar um significativo incremento da quantidade de córneas elegíveis para colheita.

Exploration d’un modèle d’étude simplifié de la spermiogenèse par l’utilisation de la levure à fission

Résumé: Les cellules germinales mâles remodèlent leur chromatine pour compacter leur noyau afin de protéger leur matériel génétique et assurer un transit optimal vers le gamète femelle. Il a été démontré que tous les spermatides de plusieurs mammifères, incluant l’homme et la souris, présentaient ce mécanisme de remodelage de la chromatine. Celui-ci est caractérisé par une augmentation transitoire de cassures d’ADN dont une quantité importante sont bicaténaires. Ce remodelage chromatinien a été étudié et semble être conservé chez plusieurs espèces, allant de l’algue à l’humain. Dans le contexte de la recherche fondamentale sur le phénomène de la spermiogenèse, il devient parfois très difficile d’investiguer certains aspects importants en vertu de l’impossibilité de réaliser des manipulations génétiques simples. Il est donc impératif de développer un nouveau modèle d’étude plus permissif afin de palier à ces difficultés encourues. Comme le processus de maturation des spores chez la levure à fission présente de grandes similitudes avec la spermiogenèse des mammifères, l’utilisation d’un modèle d’étude basé sur la sporulation de la levure à fission Schizosaccharomyces pombe a été proposée comme modèle comparatif de la spermatogenèse murine. À la suite de la synchronisation de la méiose de la souche S. pombe pat1-114, des analyses d’électrophorèse en champ pulsé (PFGE) et de qTUNEL ont permis de déterminer la présence de cassures bicaténaires transitoires de l’ADN lors de la maturation post-méiotique des ascospores nouvellement formés (t>7h). Des analyses par immunobuvardages dirigés contre le variant d’histones H2AS129p suggère la présence d’un remodelage chromatinien postméiotique dix heures suivant l’induction de la méiose, corroborant le modèle murin. Enfin, des analyses protéomiques couplées à l’analyse par spectrométrie de masse ont permis de proposer l’endonucléase Pnu1 comme candidat potentiellement responsable des cassures bicaténaires transitoires dans l’ADN des ascospores en maturation. En somme, bien que le processus de maturation des spores soit encore bien méconnu, quelques parallèles peuvent être tracés entre la maturation des ascospores de la levure à fission et la spermiogenèse des eucaryotes supérieurs. En identifiant un modèle simple du remodelage chromatinien au niveau de la spermiogenèse animale, on s’assurerait ainsi d’un outil beaucoup plus malléable et versatile pour l’étude fondamentale des événements survenant lors de la spermiogenèse humaine.

Impacts of Deepwater Horizon oil and associated dispersant on early development of the Eastern oyster Crassostrea virginica

The explosion of the Deepwater Horizon (DWH) oil platform resulted in large amounts of crude oil and dispersant Corexit 9500A® released into the Gulf of Mexico and coincided with the spawning season of the oyster, Crassostrea virginica. The effects of exposing gametes and embryos of C. virginica to dispersant alone (Corexit), mechanically (HEWAF) and chemically dispersed (CEWAF) DWH oil were evaluated. Fertilization success and the morphological development, growth, and survival of larvae were assessed. Gamete exposure reduced fertilization (HEWAF: EC201 h = 1650 μg tPAH50 L− 1; CEWAF: EC201 h = 19.4 μg tPAH50 L− 1; Corexit: EC201 h = 6.9 mg L− 1). CEWAF and Corexit showed a similar toxicity on early life stages at equivalent nominal concentrations. Oysters exposed from gametes to CEWAF and Corexit experienced more deleterious effects than oysters exposed from embryos. Results suggest the presence of oil and dispersant during oyster spawning season may interfere with larval development and subsequent recruitment.

Fertilization strategies for Sea Bass Dicentrarchus labrax (Linnaeus, 1758): effects of pre-incubation and duration of egg receptivity in seawater

Studying gamete biology can provide important information about a species fertilization strategy as well as their reproductive ecology. Currently, there is a lack of knowledge about how long sea bass Dicentrarchus labrax eggs can remain viable after being activated in seawater. The objectives of this study were to understand the effects of pre-incubation of fresh and overripe sea bass eggs in seawater and to determine the duration of egg receptivity. Pooled eggs (fresh and overripe) from four females were pre-incubated in seawater for 0 min (control), 0.5 min, 1 min, 3 min, 10 min and 30 min and then fertilized by pooled sperm from four males. The fresh eggs had a higher fertilization success than overripe eggs. Our results revealed a significant effect of pre-incubation time for both the fresh (P < 0.01) and overripe eggs (P < 0.01). Fertilization success of eggs significantly declined for both these treatments after 3 min of pre-incubation, which clearly indicates that sea bass eggs are able to be fertilized by sperm for up to 3 min after release into seawater. This study has particular importance for understanding fertilization strategies, reproductive potential, as well as reproductive ecology of sea bass.

Juego a escondidas entre Dios y el ser humano en la poesía de Antonio Machado

Este artículo pone de relieve las diversas elaboraciones y tratamientos que sufre la imagen de Dios en la poesía de Machado. Destaca el cuestionamiento que el poeta hace a las concepciones tradicionales de un Dios abstracto y de un Jesús sufriente, pasional, crucificado y dolorista, y propone un apego por un Jesús histórico, pescador y dador de una palabra imperecedera. Tanto su experiencia intimista como de abandono de Dios nos deja ante el silencio como única respuesta.

Financing social ventures by crowdfunding: The inflluence of entrepreneurs’ personality traits

Purpose – This research aims to understand the role played by social entrepreneurs’ personality traits on the choice between the traditional donation model and social crowdfunding (CF) to finance social projects. Design/methodology/approach – Social CF is examined as an instrument to capture funds for social projects, and the particular case of the Portuguese Social Stock Exchange (PSSE) is presented. The approach is quantitative in nature and the data were collected through a questionnaire that was emailed to non-governmental organizations in Portugal and founders of the projects listed on PSSE. Logistic regression was employed to predict the probability that a social entrepreneur would use PSSE rather than traditional financing. The predictor variables were based on the big five personality traits. Findings – Our investigation reveals that the agreeableness and neuroticism factors were not even considered in the results of the factorial analysis, which indicates the minor importance of these personality traits in the funding decisions of the Portuguese social entrepreneurs. The same applies to the factors of openness to new experiences and extraversion, which, although considered in the logistic analysis, showed no statistical significance. Finally, the conscientiousness personality trait seems to be the only factor that might explain the use of the PSSE platform.Originality/value – Studies on the profile of the social entrepreneurs that use CF for financing social projects are relatively rare, specifically in the context of Social Stock Exchange platforms. Additionally, there is a need to carry out more empirical evidence about the effect of social entrepreneurs’ personality traits on the decision to finance social projects through social CF platforms vis-a-vis the traditional donation model.

Blood donor motivation and recruitment : a comparative study in West of Scotland and the Sudan

In modern society, blood donor motivation and recruitment is a fundamental part of health care delivery. Well defined and documented programmes exist throughout the world but new ideas are always welcome. The situation in the Sudan is different and much remains to be done by way of comparison with elsewhere. This thesis outlines the objectives of a study, how it was supported, sponsored and achieved. It describes briefly the geography of the Sudan, the source of Sudanese economy, climate, culture and historical backgrounds. The problems of existing services in the Sudan are reviewed and a brief account of the demographic characteristics of the Sudanese population is given. Two surveys done in West of Scotland and in the Sudan are described in detail. This work discloses and compares the positive motives that enhances giving of blood and the negative motives that hinders its donation. The comparison is between an Eastern Society with a voluntary motivation not fully activated because of lack of understanding and awareness of the need to give blood voluntarily for strangers and Western Society with a well established voluntary system of donation. An addition to this research was the investigation into the immunity to tetanus and hepatitis in the Sudanese population. An estimate of the percentage of individuals with detectable levels of hepatitis A and B antibodies and tetanus antibodies is included since there is a need to establish a plasmapheresis programme as part of a good Blood Transfusion Service for the procurement of specific immunoglobulin's. This work has revealed major differences between the West of Scotland and the Sudan and suggestions are made for their resolution. The main conclusion and comparison are summarised in Chapter 7. It is hoped that many of the suggestions in this thesis can be introduced in the Sudan at an early date.

CD81 interacting proteins

Fertilization is a multistep and complex process culminating in the merge of gamete membranes, cytoplasmic unity and fusion of genome. CD81 is a tetraspanin protein that participates in sperm-oocyte interaction, being present at the oocyte surface. CD81 has also been implicated in other biological processes, however its specific function and molecular mechanisms of action remain to be elucidated. The interaction between CD81 and its binding partner proteins may underlie the CD81 involvement in a variety of cellular processes and modulate CD81/interactors specific functions. Interestingly, in a Yeast two Hybrid system previously performed in our lab, CD81 has emerged as a putative interactor of the Amyloid Precursor Protein (APP). In the work here described, bioinformatics analyses of CD81 interacting proteins were performed and the retrieved information used to construct a protein-protein interaction network, as well as to perform Gene Ontology enrichment analyses. CD81 expression was further evaluated in CHO, GC-1 and SH-SY5Y cell lines, and in human sperm cells. Additionally, its subcellular localization was analyzed in sperm cells and in the neuronal-like SH-SY5Y cell line. Subsequently, coimmunoprecipitation assays were performed in CHO and SH-SY5Y cells to attempt to prove the physical interaction between CD81 and APP. A functional interaction between these two proteins was accessed thought the analyses of the effects of CD81 overexpression on APP levels. A co-localization analysis of CD81 and some interactors proteins retrieved from the bioinformatics analyses, such as APP, AKT1 and cytoskeleton-related proteins, was also performed in sperm cells and in SH-SY5Y cells. The effects of CD81 in cytoskeleton remodeling was evaluated in SH-SY5Y cells through monitoring the effects of CD81 overexpression in actin and tubulin levels, and analyzing the colocalization between overexpressed CD81 and F-actin. Our results showed that CD81 is expressed in all cell lines tested, and also provided the first evidence of the presence of CD81 in human sperm cells. CD81 immunoreactivity was predominantly detected in the sperm head, including the acrosome membrane, and in the midpiece, where it co-localized with APP, as well as in the post-acrosomal region. Furthermore, CD81 co-localizes with APP in the plasma membrane and in cellular projections in SH-SY5Y cells, where CD81 overexpression has an influence on APP levels, also visible in CHO cells. The analysis of CD81 interacting proteins such as AKT1 and cytoskeletonrelated proteins showed that CD81 is involved in a variety of pathways that may underlie cytoskeleton remodeling events, related to processes such as sperm motility, cell migration and neuritogenesis. These results deepen our understanding on the functions of CD81 and some of its interactors in sperm and neuronal cells.

Papel do turista na conservação do património cultural e natural

Resumo O estudo realizado no âmbito deste relatório centra-se numa análise do papel do turista na conservação do património natural e cultural, em particular do Parque Nacional da Tijuca, no Rio de Janeiro. Os objetivos definidos para este trabalho são dilucidar o conceito de turismo cultural nas suas inter-relações com o ecoturismo; compreender o estado da arte em relação à intervenção do terceiro setor (ONG associações, fundações) e do turista particular na conservação do património; caracterizar o Parque Nacional da Tijuca; caracterizar a Amigos do Parque; e por fim indagar sobre a predisposição do turista para se associar à Associação dos Amigos do Parque Nacional da Tijuca. Para isso foi concebido um inquérito, realizado pela estagiária aos turistas que visitavam o parque, fazendo assim uma recolha de dados que serviram de base para as conclusões deste trabalho, levando no fim à proposta de algumas estratégias e diretivas a seguir para atrair novos associados, em particular turistas. Os resultados levam a concluir que no geral o turista não está predisposto a contribuir para a conservação e associar-se à Amigos do Parque. A percentagem de turistas que afirmaram estar predispostos a associarem-se foi de apenas 5%, sendo maioritariamente de turistas com idades entre os 25 e os 44 anos, com formação superior e provenientes dos países da América do Sul. O turista foi também questionado quanto à predisposição para fazer uma doação pontual, para a qual a taxa de respostas positiva foi mais elevada com 22%, com a contribuição também de turistas europeus. Apesar destes valores, o número de visitantes anuais do Parque Nacional da Tijuca aumenta a cada ano (prevendo-se que continue a aumentar), sendo que em 2014 foi de 3.086.207 de pessoas, e destes, cerca de 72% foram turistas. É importante conseguir o apoio destes turistas através da associação e através de doação, já que é relevante não só a nível financeiro, como também a nível de internacionalização e reconhecimento da associação e do parque, o que levará a uma maior rede de associados. Palavras-chave: ecoturismo; terceiro setor; conservação; Associação dos Amigos do Parque Nacional da Tijuca vii Abstract The study in this report focuses on an analysis of the tourist role in the conservation of natural and cultural heritage, in particular of the Tijuca National Park in Rio de Janeiro. The goals set for this work are to elucidate the concept of cultural tourism in its interrelations with ecotourism; to understand the state of the art concerning the third sector (NGO associations, foundations) and private tourist in heritage conservation; to characterize the Tijuca National Park; to characterize the Friends of the Park; and finally to inquire about the willingness of the tourist to join the Association of Friends of the Tijuca National Park. For this a survey was designed and conducted by the intern to the tourists visiting the park, thus allowing for a collection of data that formed the basis to the conclusions of this work, leading at the end to the proposal of some strategies and policies to attract new members, particularly tourists. The results lead to the conclusion that as a rule the tourist is not willing to contribute to the conservation and join the Friends of the Park. The percentage of tourists who assumed they were willing to join the association was only 5%, and mostly tourists aged 25 and 44, with higher education, and from the South American countries. Tourists were also asked about their willingness for giving donations, for which the rate of positive responses was higher 22%, with the contribution of European tourists. Despite these numbers, the number of annual visitors to the Tijuca National Park increases every year (and it is expected to continue to increase). In 2014 ir received 3,086,207 visitors, and of these, about 72% were tourists. It is important to get the support of these tourists through association and through donation, since it is relevant not only financially, but also as a tool of the internationalization and recognition of the association and the park, which will lead to a larger network of associates. Keywords: ecotourism; third sector; conservation; Association of Friends of the Tijuca National Park

Validation of the haemoglobin colour scale for screening blood donors in Malawi

Background In 2009 Malawi introduced a new protocol to screen potential blood donors for anaemia, using the WHO Haemoglobin Colour Scale (HCS) for initial screening. Published studies of the accuracy of the HCS to screen potential blood donors show varying levels of accuracy and opinion varies whether this is an appropriate screening test. The aim of the study was to assess the validity of the HCS, as a screening test, by comparison to HemoCue in potential blood donors in Malawi. Study design and Methods This was a blinded prospective study in potential blood donors aged over 18 years, at Malawi Blood Transfusion Service in Blantyre, Malawi. Capillary blood samples were analysed using the HCS and HemoCue, independent of each other. The sensitivity and specificity of correctly identifying ineligible blood donors (Hb≤12g/dL) were calculated. Results From 242 participants 234 (96.7%) were correctly allocated and 8 (3.3%), were wrongly allocated on the basis of the Haemoglobin Colour Scale (HCS) compared to HemoCue, all were subjects that were wrongly accepted as donors when their haemoglobin results were ≤12.0g/dL. This gave a sensitivity of 100% and specificity of 96.7% to detect donor eligibilty. The negative predictive value of the HCS was 100% but the positive predictive value to identify ineligible donors on the basis of anaemia was only 20%. Conclusions Initial screening with the HCS correctly predicts eligibility for blood donation in the majority of potential blood donors at considerable cost saving compared with use of HemoCue as the first line anaemia screening test, however, by this method a small number of anaemic patients were allowed to donate blood.

Movimento vida: motivação e organizações sem fins lucrativos

As organizações sem fins lucrativos, OSFL, têm um papel cada vez mais importante na nossa sociedade e torna-se cada vez mais crítico ter uma performance eficaz. Em resposta, os gestores destas organizações têm demonstrado um crescente interesse por práticas e princípios que irão ajudá-los a construir organizações de alto desempenho, ao invés de apenas programas fortes de gestão. Este estudo com o tema “Movimento Vida – Motivação e Organizações Sem Fins Lucrativos” surge na necessidade de sistematizar um movimento que a dada altura transcendeu os seus intervenientes, paralelamente à necessidade de estudar a motivação que levou a que um país inteiro se mobilizasse e envolvesse em torno de uma causa assim como as razões que levaram à criação desta Organização Sem Fins Lucrativos, o Movimento Vida. Este estudo centra-se à volta de dois temas indissociáveis ao Movimento Vida: Organizações Sem Fins Lucrativos e Motivação. A metodologia utilizada numa primeira fase centra-se na revisão bibliográfica sobre estes dois temas e, ao efetuar esta revisão bibliográfica foi sempre tido em conta as necessidades do Movimento Vida e também os conceitos que servem de mais-valia à organização. Ao longo desta revisão bibliográfica é feito, muitas vezes, o paralelismo entre os conceitos das organizações com fins lucrativos e a forma de adaptar alguns desses mesmos conceitos para as OSFL. Na segunda parte do estudo é feita uma descrição do Movimento Vida enquanto OSFL. Por fim, na terceira parte deste estudo, de acordo com os objetivos, é identificada a missão, visão e valores do Movimento Vida, a proposta de criação de valor assim como o estudo da maneira como a família Martins viu e viveu a motivação gerada em torno do “Caso Gustavo” e também a motivação que deu origem à criação do Movimento Vida. Conclui-se através do presente estudo que a solidariedade é um forte catalisador de mobilização social e que existe nas pessoas uma forte motivação de dar através do sentimento de poder ajudar. Conclui-se ainda que, por parte da família Martins, a vontade de retribuir aos portugueses o carinho, o apoio e a mobilização de todos para que fosse encontrado um dador para o Gustavo foi o fator motivacional mais forte para que fosse criado o Movimento Vida. Foram concretizados os objetivos de identificar a missão, a visão, os valores e os stakeholders do Movimento Vida.

Insuficiência ovárica prematura

Trabalho Final do Curso de Mestrado Integrado em Medicina, Faculdade de Medicina, Universidade de Lisboa, 2014

The impact of Portuguese demographic changes on the demand and supply of blood in the region of Algarve

Dissertação de Mastrado, Gestão de Unidades de Saúde, Faculdade de Economia, Universidade do Algarve, 2016