We explored the role that exogenous and endogenous competitors for attention play in infants’ abilities to encode and retain information over a 6‐month period. Sixty‐six children visited the laboratory at 15 months, and 32 returned for a second visit at 21 months. Children observed models of conventional‐ relation and enabling‐relation action sequences. Half the children were distracted by a “Mister Monkey” mechanical toy during the conventional‐relation sequence, while the other half was distracted during the enabling‐relation sequence. The Early Childhood Behavior Questionnaire indexed endogenous factors at both ages. Immediate postmodel production of target actions indexed encoding efficiency, and 6‐month production of target actions indexed long‐term recall. The exogenous distracter impacted encoding efficiency (i.e., immediate recall), but not long‐term recall. Endogenous factors (i.e., temperament) were primarily associated with long‐term recall. Of special interest was our finding that endogenous factors, especially surgency, moderated the effect of the exogenous distracter. It appears that when learning conventional‐relation sequences in the presence of exogenous distracters, surgency mobilizes attentional resources toward the learning objective; however, when learning enabling‐relation sequences under the same conditions, surgency either boosts the saliency of the distracters or boosts children’s susceptibility to them.

Einleitung: Die im Genom der Schweine integrierten porzinen endogenen Retroviren (PERV) gehören zu den potentiellen humanpathogenen Erregern, die eines der Risiken bei der Xenotransplantation darstellen. Für die Abschätzung des Infektionsrisikos von PERV sind drei Verfahrensweisen von Bedeutung: Erstens die Evaluierung der PERV-Freisetzung aus porzinen Zellen und Geweben; Zweitens die Etablierung eines In vivo-Infektionsmodells und Drittens ein retrospektives Screenen von Patienten. Methoden: Die PERV-Expression in Inselzellen von Schweinen der Deutschen Landrasse wurde in vitro und in vivo evaluiert. Anschließend wurde PERV auf nicht-humanen Primatenzellen passagiert. In einem zweiten Modellversuch wurde murinen Zellen in vitro und SCID-Mäusen in vivo zellfreies PERV appliziert. Schließlich wurden Seren von Patienten analysiert. Ergebnisse: Die untersuchten Inselzellen setzten keine Viruspartikel frei und konnten somit weder humane Zellen noch BALB/c-Mäuse infizieren. Die verwendeten Affenzellen produzierten infektiöses PERV mit geringer Replikation. Weder in den murinen Modellversuchen noch in den untersuchten Patienten wurde eine Übertragung von PERV beobachtet. Schlussfolgerung: Schweine der Deutschen Landrasse könnten als Ausgangsbasis für die Zucht sicherer Schweine für die Xenotransplantation dienen. Da keine Infektion verschiedener muriner Zellen mit PERV beobachtet wurde, muss angenommen werden, dass Publikationen anderer Arbeitsgruppen, die eine PERV-Infektion in SCID-Mäusen diagnostizierten, ein falsch-positives Ergebnis aufgrund von Mikrochimärismus oder aufgrund von Pseudotypisierungen mit murinen endogenen Retroviren wiedergeben. Unsere Befunde werden dadurch erhärtet, dass der Rezeptor für PERV-A auf murinen Zellen nicht exprimiert wird und diese auch in vitro nicht infiziert werden konnten. In Übereinstimmung mit den weltweit etwa 200 behandelten Patienten konnte auch in den beiden neuen Studien keine Übertragung von PERV festgestellt werden. / Objective: Porcine endogenous retroviruses (PERVs) are integrated in the porcine genome and are able to infect human cells in vitro. Therefore, PERVs are one of the possible pathogens which poses a risk for xenotransplantations. In this study three significant methods were used to evaluate the infectious risk of PERV: The release of PERV particles from porcine cells and tissues, the formation of an in vivo infection model and a retrospective screening of patients. Methods: Islet cells from german landrace pigs were co-cultivated with human cells in vitro and were transplanted in BALB/c mice in vivo. Serial passaging experiments were performed with nonhuman primate cells. Murine cells were incubated in vitro and SCID mice in vivo with PERV. Sera of patients who were treated ex vivo with porcine liver cells and who had received islet cells were investigated for antibodies against PERV. Results: No virus release were observed in german landrace islet cells, thus they were neither able to infect human cells nor BALB/c mice. The used nonhuman primate cells released low replicating PERVs. None of the murine cells could be infected by PERV and no provirus integration was observed in different SCID mice organs. PERV-specific antibodies were found in none of the investigated patients. Conclusion: German landrace pigs could be used as a source for breeding safe genetically modified pigs suitable for xenotransplantation. Since there were no detectable PERV infection of different murine cells and SCID mice, it have to be supposed, that previously reported PERV transmissions to SCID mice might be due to microchimerism or to pseudotyping of murine endogenous retroviruses. Our results were confirmed by the fact, that the receptor for PERV-A is not expressed on murine cells and that these cells could not be infected in vitro. The absence of a PERV transmission in the investigated patients, correspond to the results obtained from approximately twohundred treated patients worldwide.

O neuroblastoma é o tumor sólido mais comum e com maior índice de letalidade em crianças. Diversas famílias de retrovírus endógenos humanos (HERV) estão presentes no genoma humano, em diferentes níveis de integridade, e são reativadas sob diferentes circunstâncias. A atividade de HERV tem sido cada vez mais sido associada a doenças como câncer, doenças autoimunes e ainda com a infecção por vírus exógenos. O principal objetivo deste projeto foi avaliar a expressão de retrovírus endógenos das famílias H (HH), W (HW) e K (HK) em pacientes diagnosticados com neuroblastoma. Amostras tumorais e amostras controle foram submetidas a extração de RNA total, síntese de cDNA e PCR em fase única. Os produtos de HERV foram submetidos ao sequenciamento em larga escala. No total, 43 loci de HH e 14 loci de HW foram diferencialmente expressos entre os grupos e 202 loci de HK foram detectados. As análises de expressão somadas ao contexto genético e epigenético de neuroblastoma, permitiram com que várias hipóteses fossem levantadas acerca da regulação da expressão de HERV neste tumor. A hipometilação geral do tecido tumoral pode ter um papel importante na expressão gênica e na reativação de retrotransposons, podendo ser a principal razão para a expressão de HERV neste contexto. / Neuroblastoma represents the most common solid tumor as well as the most lethal form of tumor in children. Several families of human endogenous retroviruses (HERV) are present in human genome in different integrity levels, and they are reactivated under different circumstances. HERV activity has been linked to diseases such as cancer, autoimmune diseases and even with the infection by exogenous viruses. The main goal of this project was to evaluate the expression of endogenous retroviruses families H (HH), W (HW) and K (HK) in patients diagnosed with neuroblastoma. Tumor samples and control samples were subjected to RNA extraction and a single round in-house RT-PCR. HERVs amplicons were next generation sequenced to access the specific origin of transcripts. Overall, 43 HH loci and 14 HW loci were differentially expressed between groups and, 202 HK loci was detected. Taken together, HERV expression analysis and genetic and epigenetic context of neuroblastoma provided several hypotheses about regulation of HERV expression in this type of tumor. The global hypomethylation of tumoral tissue may have a role in genes expression and retrotransposons reactivation, which may be the main reason for HERV expression in this context.

[pt] Neste trabalho estudamos uma classe de problemas de otimização estocástica com incertezas endógenas que é formulado como um problema de programação não-linear inteira (MINLP). Esta classe de problemas difere dos problemas de otimização estocástica geralmente estudados na literatura pelo fato de que que a distribuição de probabilidade dos parâmetros aleatórios depende das decisões tomadas. Apesar de discutido dentro do contexto do problema de logística humanitária, a metodologia proposta e os resutados obtidos são válidos para uma classe geral de problemas que agrega uma variedade de aplicações. Em particular, propõe-se (i) uma técnica de convexificação de polinômios de variáveis binárias, (ii) um algoritmo de geração de cortes e (iii) a incorporação dos conceitos de importance sampling dentro do contexto de otimização estocástica de modo a permitir a solução de grandes instâncias do problema. Os resultados computacionais apresentados demonstram as vantagens da metodologia proposta ao permitir a solução de instâncias significativamente maiores que aquelas atualmente apresentadas em trabalhos relacionados. / [en] In this work we study a class of stochastic programming problems with endogenous uncertainty – i.e., those in which the probability distribution of the random parameters is decision-dependent – which is formulated as a mixed integer non-linear programming (MINLP) problem. Although discussed in the context of the humanitarian logistics problem, the proposed methodology and obtained results are also valid for a more general class of problems which comprehends a variety of applications. In particular, we propose (i) a convexification technique for polynomials of binary variables, (ii) an efficient cutgeneration algorithm and (iii) the incorporation of importance sampling concepts into the stochastic programming framework so as to allow the solution of large instances of the problem. Computational results demonstrate the effectiveness of the proposed methodology by solving instances significantly larger than those reported in related works.

Submitted by Silvana Teresinha Dornelles Studzinski (sstudzinski) on 2015-10-21T14:34:11Z No. of bitstreams: 1 RENATO BRASIL KOURROWSKI_.pdf: 7191417 bytes, checksum: 38d0455da7516cb93650904507e70ef6 (MD5) / Made available in DSpace on 2015-10-21T14:34:11Z (GMT). No. of bitstreams: 1 RENATO BRASIL KOURROWSKI_.pdf: 7191417 bytes, checksum: 38d0455da7516cb93650904507e70ef6 (MD5) Previous issue date: 2015-05-28 / Nenhuma / Possuindo como tema central o desenvolvimento local, esta pesquisa tem o objetivo de propor, com potencialidade de utilização no âmbito da esfera pública, um método de aceleração e a identificação dos elementos que contribuem para o desenvolvimento industrial local das cidades médias brasileiras, a partir da teoria do desenvolvimento endógeno. O presente trabalho adota uma abordagem qualitativa, tendo como método de pesquisa o estudo de caso. Inicialmente, tendo como base o referencial teórico proposto, uma entrevista com ator chave e a utilização de dados secundários, foi realizado um estudo de um caso singular sobre o processo de desenvolvimento no município de Passo Fundo entre os anos de 2005 e 2012. A partir daí foi gerada uma primeira versão do referido método de aceleração (M0). Na sequência, foram realizadas 20 entrevistas semiestruturadas com atores sociais relevantes ligados ao tema da pesquisa (empresários, especialistas e membros do governo). Isto permitiu a identificação de 68 elementos que contribuem para o desenvolvimento industrial local, sendo a infraestrutura, em suas diferentes dimensões, o principal destaque considerado. Ao final, se propõe um refinamento do método de aceleração para o desenvolvimento industrial local das cidades médias brasileiras, visando o preenchimento de uma lacuna acadêmica e no campo prático da gestão, dada as especificidades propostas a um processo de desenvolvimento local endógeno que visa, simultaneamente, a atração de grandes empresas, o fortalecimento das firmas locais, a utilização das matérias-primas disponíveis (por exemplo, oriundas da agricultura) e o encadeamento entre estes vários atores tanto da ótica das respectivas indústrias, como das cadeias produtivas locais. / Having as the central theme the local development, this research focuses on proposing, with potential within the public sphere, an acceleration method and identification of elements that contribute to local industrial development of the mid-sized Brazilian cities, from the theory of the endogenous development. The present study adopts a qualitative approach using the case study research method. Initially, based on the proposed theoretical framework, an interview with a key actor and the use of secondary data, we conducted a single case study of the development process in the city of Passo Fundo between the years 2005 and 2012. From this time on a first version of this acceleration method was generated (M0). Next, there were 20 semi-structured interviews with relevant actors related to the subject of research (entrepreneurs, experts and government officials). This permitted the identification of 68 elements that contribute to local industrial development and the infrastructure, in its different dimensions, being the main highlight considered. Finally, we propose a refinement of the acceleration method for the local industrial development of mid-sized Brazilian cities, aimed at filling an academic gap and practical management fields, given the specific proposals to an endogenous local development process aimed at simultaneously, the attraction of large enterprises, the strengthening of local companies, the use of raw materials available (for example, originating from agriculture) and the linkage between these various actors from both the perspective of the respective industries, and also from local production chains.

Parallèlement au prix, le délai de livraison est un facteur clé de compétitivité pour les entreprises. De plus les entreprises sont plus que jamais obligées de respecter ce délai promis. La combinaison du choix du prix et du délai promis implique de nouveaux compromis et offre de nombreuses perspectives. Un délai plus court peut entraîner une augmentation de la demande, mais augmente également le risque de livraison tardive et donc décourager les clients. A contrario un délai plus long ou un prix plus élevé entraîne généralement une baisse de la demande. Or malgré le rôle stratégique conjoint du prix et des délais et leurs impacts sur la demande, dans la littérature en gestion des opérations on suppose très généralement une demande exogène (fixée a priori) même si la conception de la chaîne impacte fortement les délais (localisation des sites, positionnement des stocks,..) et donc la demande. Nous nous sommes donc intéressés à ces choix de fixation des délais promis et du prix dans un contexte de demande endogène.La littérature traitant du choix du délai et du prix sous demande endogène a principalement considéré un contexte de fabrication à la commande (Make to Order). Un papier fondateur de Palaka et al en 1998 a présenté cette problématique avec une modélisation de l’entreprise par une file d’attente M/M/1 et nos travaux se placent dans la suite de ce travail. Notre revue de la littérature a permis d'identifier de nouvelles perspectives et nous proposons trois extensions dans cette thèse.Dans notre première contribution, en utilisant le cadre de Palaka et al, nous considérons que le coût de production est une fonction décroissante du délai. Dans tous les articles publiés dans ce contexte, le coût de production unitaire a été supposé constant. Pourtant en pratique, le coût de production unitaire dépend du délai promis, l'entreprise pouvant mieux gérer le processus de production et réduire les coûts de production en proposant des délais plus longs aux clients.Dans la deuxième contribution, nous considérons toujours le cadre de Palaka et al, mais modélisons l'entreprise comme une file d'attente M/M/1/K, pour laquelle la demande est donc rejetée s'il y a déjà K clients dans le système. Dans la littérature issue du travail de Palaka seule la file d'attente M/M/1 a été utilisée, ce qui signifie que tous les clients sont acceptés, ce qui peut entraîner de longues durées de séjour dans le système. Notre idée est basée sur le fait que rejeter certains clients, même si cela peut apparaitre dans un premier temps comme une perte de demande, pourrait aider à proposer un délai plus court pour les clients acceptés, et finalement conduire à une demande et donc un profit plus élevé.Dans la troisième contribution nous étudions un nouveau cadre pour le problème du délai et du prix en fonction de la demande endogène, en modélisant une chaîne logistique composée de deux étapes de production, modélisée par un réseau de files d’attente tandem (M/M/1-M/M/1). Dans la littérature avec ce cadre multi-entreprise, tous les articles ont considéré qu'un seul acteur avait des opérations de production, l'autre acteur ayant un délai nul. Nous avons étudié les scénarios centralisés et décentralisés.Pour chacun des nouveaux problèmes nous avons proposé des formulations maximisant le profit composé du revenu diminué des coûts de production, de stockage et pénalité de retard, et fourni des résolutions optimales, analytiques ou numériques. Ces résolutions nous ont amenés à démontrer de nouveaux résultats (retard moyen dans une M/M/1/K ; condition pour que des contraintes de service locales permettent d’assurer une contrainte de service globale dans un système en tandem). Nous avons mené des expériences numériques pour voir l’influence des différents paramètres. / Along with the price, the delivery lead time has become a key factor of competitiveness for companies and an important purchase criterion for many customers. Nowadays, firms are more than ever obliged to meet their quoted lead time, which is the delivery lead time announced to the customers. The combination of pricing and lead time quotation implies new trade-offs and offers opportunities for many insights. For instance, on the one hand, a shorter quoted lead time can lead to an increase in the demand but also increases the risk of late delivery and thus may affect the firm’s reputation and deter future customers. On the other hand, a longer quoted lead time or a higher price generally yields a lower demand. Despite the strategic role of joint pricing and lead time quotation decisions and their impacts on demand, in the operations management literature an exogenous demand (a priory a known demand) is generally used in supply chain models, even if the design of the supply chain has a strong impact on lead times (i.e., sites location, inventory position, etc.) and thus affects the demand. Therefore, we are interested in the lead time quotation and pricing decisions in a context of endogenous demand (i.e., demand sensitive to price and quoted lead time).The literature dealing with pricing and lead time quotation under an endogenous demand mainly considered a make to order (MTO) context. A pioneer paper, Palaka et al. (1998), investigated this issue by modeling the company as an M/M/1 queue, and our work follows their footsteps. Our review of the literature allowed to identify new perspectives for this problem, which led to three main contributions in this thesis.In our first contribution, using Palaka et al.’s framework, we consider the unit production cost to be a decreasing function in quoted lead time. In most published papers, the unit production cost was assumed to be constant. In practice, the unit production cost generally depends on the quoted lead time. Indeed, the firm can manage better the production process and reduce the production cost by quoting longer lead time to the customers.In the second contribution, we still consider Palaka et al.’s framework but model the firm as an M/M/1/K queue, for which demand is rejected if there are already K customers in the system. In the literature on single firm setting following Palaka et al.’s research, only the M/M/1 queue was used, i.e., where all customers are accepted, which might lead to long sojourn times in the system. Our idea is based on the fact that rejecting some customers, might help to quote shorter lead time for the accepted ones, which might finally lead to a higher profitability, even if in the first glance we lose some demand.In the third contribution, we study a new framework for the lead time quotation and pricing problem under endogenous demand as we model the supply chain by two production stages in a tandem queue (M/M/1-M/M/1). In the literature with multi-firm setting, all papers considered that only one actor has production operations and the other actor has zero lead time. We investigated both the centralized and decentralized decision settings.For each problem studied, we formulated a profit-maximization model, where the profit consists of a revenue minus the production, storage and lateness penalty costs, and provides the optimum result (analytically or numerically). These resolutions led us to demonstrate new theoretical results (such as the expected lateness in an M/M/1/K, and the sufficient condition required to satisfy the global service constraint in a tandem queue by only satisfying the local service constraints). We also conducted numerical experiments and derived managerial insights.

This thesis investigates different aspects of competition under uncertainty using the tools of game theory. In Chapter 1, I consider a quantity oligopoly game. One of the firms is presented with an opportunity to commit to some output before the demand becomes known, but may add to it afterwards, then moving simultaneously with the rivals. I show that the more cost-efficient firm is more likely to behave like a Stackelberg leader, i.e. to produce the optimal Stackelberg leader quantity ex-ante and refrain from adding to it later, letting the rivals respond to its ex-ante output in the manner of Stackelberg followers. In Chapter 2, I study a model of an electoral contest. Two symmetric parties allocate their endowments to building platforms on various issues before the start of a campaign. Next, one of the issues becomes decisive in the course of the campaign with a commonly known probability. The outcome of the election depends on the difference in competence in this issue. I show that if the payoff functions are convex in this difference-the case of 'increasing returns to power'-parties differentiate each other by selecting different campaign issues. On the contrary, when the payoff functions are concave in this difference-the case of 'decreasing returns to power'-parties mimic each other by investing the same amounts into the same issues. Thus, incentives for selecting campaign issues depend critically on the shape of the payoff functions, which might be determined by (1) a non-linear technology transforming parties' investment in various topics into voters' perception of their competence, (2) or parties' inherent motivation for winning by a big margin due to parties' ideological convictions or rent-seeking, (3) or an electoral system giving winners or big parties a disproportionate advantage in the assigned number of seats, (4) or a relatively high extent of power given to the winning party once in office.

Les rétrovirus endogènes (ERV) sont constitutifs du génome des eucaryotes et représentent environ 400000 loci dans le génome humain divisés en différentes familles. Ces HERV (Human ERV) sont pour la majorité silencieux en contexte physiologique excepté dans le placenta mais présentent une activité transcriptionnelle en contexte pathologique comme par exemple dans les cancers. Il est difficile de comprendre de façon systématique les mécanismes de régulation/dérégulation des HERV et leur implication en contexte physiopathologique car il n’existe à ce jour aucun critère permettant de distinguer qu’elles sont les longues terminaisons répétées (LTR) transcriptionnellement actives dans l’ensemble de ces éléments de régulation. Nous avons développé deux générations de puces à ADN haute densité afin d’appréhender quelles étaient les LTR réactivées dans les cancers et de comprendre les mécanismes sous-jacents à la transcription des HERV. Avec la première version de la puce HERV, nous avons notamment identifié six loci de la famille HERV-W différentiellement exprimés dans le cancer testiculaire dont le locus ERVWE1 qui code pour la syncytine-1 impliquée dans la morphogénèse placentaire. L’analyse de l’ADN des tumeurs et des tissus sains adjacents démontre que l’hypométhylation des régions U3 promotrices est un pré-requis à l’activation des HERV. La deuxième version de la puce HERV a été utilisée pour une recherche de biomarqueurs pronostiques dans le cancer du poumon non à petites cellules. Ceci a permis de mettre en évidence des réactivations de HERV dans certains échantillons cancéreux et illustre la difficulté d’une telle approche au regard des disparités inter-individus / Endogenous Retroviruses (ERVs) are inherited part of the Eukaryotic genomes, and represent about 400,000 loci in the Human genome divided in distinct families. The majority of HERVs (Human ERV) are mainly silent in most physiological contexts excepted in placenta, whereas a significant expression is observed in pathological contexts such as cancers. It is difficult to understand HERV (de)regulation mechanisms and their implication in physio-pathological contexts, as there is no criteria defining transcriptional active promoters HERV long terminal repeats (LTRs) among all these regulatory élements. We developed two versions of highdensity DNA microarray to specifically detect LTR reactivated in cancers and try to understand transcription mechanism of HERV. With the first version of HERV-microarray, we identified six HERV-W loci over-expressed in testicular cancer, including the domesticated ERVWE1 locus which produces an envelope protein dubbed Syncytin-1 associated with placenta development. The analysis of DNA from tumoral versus normal tissue reveals that hypomethylation of U3 promoters in tumors is a prerequisite of HERV activation. The second version of HERV-microarray was used to identify prognosis biomarkers in non small cell lung cancer. This study identified HERV reactivation in some samples and highlighted difficulties of such approach due to inter-individuals disparities

A sincronização reprodutiva em invertebrados marinhos é comum, e organismos do entremarés se valem de pistas exógenas, como os ciclos ambientais gerados pelos movimentos da Terra e da Lua, na sincronização de uma componente endógena que colocará em fase pelo menos uma etapa do ciclo reprodutivo. Em estudos anteriores com cracas, notou-se uma clara relação entre emissão larval e elevada produção fitoplanctônica, enquanto outros apontam uma estrita relação com os regimes de maré e fases da lua. Neste projeto pretendeu-se detectar as variáveis ambientais associadas à ritmicidade da emissão naupliar na craca Chthamalus bisinuatus em condições constantes de laboratório, permitindo, então, a detecção de uma componente endógena associada a tal atividade e acompanhar a mesma atividade em campo, podendo associar quais condições ambientais em tempo real influenciam essa etapa do ciclo reprodutivo. Para esses objetivos, populações foram submetidas a testes em condições constantes de laboratório, sendo as variáveis temperatura, fotoperíodo e tempo de imersão testados isoladamente e conjugados dois a dois. Em campo, populações do cirripédio tiveram monitoradas por um período de 32 dias, durante o qual a atividade de emissão larval, e as variáveis temperatura, fluxo de água e concentração de clorofila-a foram medidas a fim de se estabelecer uma relação entre as emissões e tais variáveis. Os resultados indicam a existência de uma componente endógena marcando o ritmo de emissão larval e da atividade de muda sincronizada com o ciclo de amplitude de maré (14.4 dias), bem como um papel relevante da ação sinérgica da oscilação ultradiana da altura da maré e da temperatura como modulador da sincronização de tais atividades. Em campo, os eventos extremos de temperatura, a concentração de clorofila-a (um indicador da disponibilidade de alimentos para os adultos) e o fluxo de água atuaram como indutores da emissão larval em um intervalo antecedente de 1 e 6 dias para as duas primeiras variáveis, e um intervalo de 1 a 3 dias posteriores para a última variável, provando, então, serem importantes na determinação do momento da emissão larval. Portanto, se conclui que ritmos endógenos associados à amplitude de maré podem explicar parcialmente o padrão circa semilunar centrado nos períodos de quadratura examinados em outras populações, mas, como é mostrado aqui, tal ritmicidade pode ser interrompida por variações de temperatura, disponibilidade de alimento e intenso fluxo de água. Discute-se que o primeiro efeito pode estar relacionado a mecanismos fisiológicos que garantem a reprodução de indivíduos submetidos a maiores riscos de mortalidade, e que a alimentação é um recurso limitante para a reprodução da população estudada. Em uma escala temporal menor, a ritmicidade endógena, sincronizada pela combinação de temperatura e tempo de imersão, favorece a emissão larval em períodos de maré-alta. Na ausência de outros fatores ambientais que controlam a emissão, uma componente endógena permitirá a emissão larval nos momentos de maré-alta dos períodos de quadratura, o que promoveria a retenção na linha de costa e minimizaria o risco de encalhe. / Synchronized reproduction is common among marine invertebrates, and intertidal organisms make use of exogenous cues, such as environmental cycles generated by the movements of the Earth and Moon, to synchronize their biological clocks in phase with such oscillations, at least in one stage of the reproductive cycle. In previous reports on barnacle rhythms, some studies have stressed a clear relationship between larval emission and high phytoplankton production, while others indicate a close relationship with the regimes of tide and moon phases. In this project we intended to detect environmental variables associated with the rhythmic larval release activity in the barnacle Chthamalus bisinuatus, both in constant laboratory conditions, allowing the detection of an endogenous component associated with such activity, and in the field, by monitoring larval release and other environmental conditions that might influence the reproductive cycle. For such purposes, populations were tested in constant laboratory conditions, where the variables temperature, photoperiod and time of immersion were tested both alone and combined in pairs, and in the field, by monitoring reproductive activity in populations of these cirripedes for 32 days, together with temperature, water flow, and chlorophyll-a concentration, as to establish relationships between larval release and these variables. The results indicate the existence of an endogenous component setting the rhythm of emission and larval molt activity synchronized with the cycle of tidal range (14.4 days), and the use of tides and daily fluctuations in temperature as cues in the synchronization of ultradian release activities. In the field, extremes of temperature, peaks of chlorophyll-a concentration (a proxy of food availability for adults) and water flow, triggered naupliar release 1 and 6 days ahead, for the first two variables, and 1 and 3 days before for the last one, thus proving to be important variables in determining the time of larval emission. Therefore, it is concluded that endogenous tidal-amplitude rhythms may partly explain sharp fortnight patterns centered at neap-tide periods in populations examined elsewhere, but, as shown herein, such rhythmicity may be disrupted by variations of temperature, food availability and intense water flow. It is argued that the first effect may be related to a physiological mechanism ensuring reproduction in individuals at a higher mortality risk, and that food is a limiting resource for reproduction in the study population. In a shorter time scale, endogenous rhythmicity, entrained by the combined control of temperature and immersion time, favors high-tide larval release. In the absence of other environmental release-inducing factors, endogenous timing would lead to high-tide release during neap periods, which would favor coastal retention and minimize stranding risk.

Dietary protein quality depends on two key measures: true ileal protein digestibility and the metabolic utilization of absorbed amino acids (AA). The objectives of this study were to determine the influence of two dietary factors (antinutritional factors and peptides) on ileal endogenous protein flows; to validate the intubation technique used in humans for ileal digesta sampling; to determine the postprandial metabolic utilization of dietary AA depending on their delivery form and to assess the validity of the growing pig for predicting true ileal protein digestibility in the adult human. Investigations were undertaken in the growing rat, growing pig and adult human. Ileal digesta were collected from euthanised rats, post valve T-caecum cannulated pigs, and naso-ileal intubated conscious adult humans. Ileal endogenous nitrogen (N) and AA were measured using a protein-free (PF) diet, diets containing 15N-labelled casein in the intact (C) or hydrolysed (HC) form, or a diet based on free AA (diet A), for which some dispensable AA were omitted to allow a direct determination of their endogenous flows. Digesta centrifugation and ultrafiltration (diet HC) allowed for the determination of ileal endogenous protein flows and the extent of tracer (15N) recycling. Antinutritional factors from a crude extract of kidney beans (Phaseolus vulgaris), when given at amounts commonly ingested in practice, enhanced ileal endogenous protein flows (rats, PF diet). After adaptation to the diet, body N balance per se did not influence ileal endogenous protein flows (rats, diets PF and A) but dietary peptides led to greater ileal endogenous AA and N flows compared with a protein-free diet. Dietary peptides (HC), compared with peptides naturally released in the gut during protein digestion (C), did not enhance ileal endogenous protein flows (rats, pigs, and humans). The extent of tracer recycling, however, was maximal in frequently-fed rats, lower in meal-fed pigs and minimal in meal-fed humans (65, 21, and 11% of 15N-labelled ileal endogenous proteins, respectively). Naso-ileal intubation for ileal digesta sampling in humans was shown to be an accurate method and evidence was obtained supporting the growing pig as a valid model for predicting true ileal protein digestibility in the adult human. Finally, the form of delivery of dietary AA (from HC or C) influenced the postprandial metabolic fate of dietary AA, especially in terms of AA catabolism kinetics. However, the overall nutritional value of C and HC were similar.