970 resultados para energetic constraint


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Vanadium compounds mimic most of the metabolic effects of insulin, suggesting that it might be useful to improve utilization of dietary carbohydrate. This work evaluated the effect of dietary ammonium metavanadate (H(4)NO(3)V) on the growth performance and energy metabolism of pacu, an omnivorous South America characin. Two hundred and eighty-eight fish were distributed into four blocks according to the body weight (21.8 +/- 1.7, 28.5 +/- 2.0, 28.4 +/- 1.9, 35.7 +/- 1.9 g), stocked in 24 plastic tanks and fed twice daily with isonitrogenous and isoenergetic diets containing six levels of H(4)NO(3)V (0, 10, 50, 100, 300 and 1000 mg kg(-1)) for 60 days. Increasing levels of dietary ammonium metavanadate did not improve growth (P > 0.05), and the highest level of inclusion (1000 mg kg(-1)) reduced performance (P < 0.05). Blood glucose levels decreased (P < 0.05) in fish fed 300 and 1000 mg kg(-1) H(4)NO(3)V, but no differences were observed in other blood metabolites. A slight increase in muscle lipid content was observed in fish fed a diet containing 300 mg kg(-1) H(4)NO(3)V. Based on the results of this study, there is no benefit in supplementing pacu diets with metavanadate.

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In long-lived species with slow maturation, prebreeders often represent a large percentage of the individuals alive at any moment, but their ecology is still understudied. Recent studies have found prebreeding seabirds to differ in their isotopic (and trophic) niche from adult breeders attending the same nesting colonies. These differences have been hypothesized to be linked to the less-developed foraging performance of younger and less-experienced immatures or perhaps to their inferior competitive abilities. Such differences from adults would wane as individuals mature (“the progressive ontogenetic shift hypothesis”) and could underpin the prolonged breeding deferral until adulthood displayed by those species. This study documents a marked difference in the nitrogen and carbon isotopic ratios measured in the whole blood of immatures and breeders in 2 pelagic seabird species (Cory’s shearwaters, Calonectris borealis, and black-browed albatrosses, Thalassarche melanophris) nesting in contrasting environments. However, blood isotopic values did not present a relationship with prebreeder age, suggesting no gradual ontogenetic shift from an immature toward an adult isotopic niche. Furthermore, isotopic signatures of sabbatical adults could not be separated from those of immatures attending the same colonies, but were clearly segregated from adult breeders. These results suggest that isotopic differentiation between immatures and breeders is mainly linked to a factor unrelated to previous experience and hence probably unrelated to a hypothetical gradual improvement of foraging competence or competitive abilities. Any ecological differentiation between breeders and nonbreeders is more likely related to the severity of the central-place foraging constraints and to the energetic requirements of reproduction (“the reproductive constraint hypothesis”).

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Projeto de Graduação apresentado à Universidade Fernando Pessoa como parte dos requisitos para obtenção do grau de Licenciada em Fisioterapia

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Declarative techniques such as Constraint Programming can be very effective in modeling and assisting management decisions. We present a method for managing university classrooms which extends the previous design of a Constraint-Informed Information System to generate the timetables while dealing with spatial resource optimization issues. We seek to maximize space utilization along two dimensions: classroom use and occupancy rates. While we want to maximize the room use rate, we still need to satisfy the soft constraints which model students’ and lecturers’ preferences. We present a constraint logic programming-based local search method which relies on an evaluation function that combines room utilization and timetable soft preferences. Based on this, we developed a tool which we applied to the improvement of classroom allocation in a University. Comparing the results to the current timetables obtained without optimizing space utilization, the initial versions of our tool manages to reach a 30% improvement in space utilization, while preserving the quality of the timetable, both for students and lecturers.

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Solving a complex Constraint Satisfaction Problem (CSP) is a computationally hard task which may require a considerable amount of time. Parallelism has been applied successfully to the job and there are already many applications capable of harnessing the parallel power of modern CPUs to speed up the solving process. Current Graphics Processing Units (GPUs), containing from a few hundred to a few thousand cores, possess a level of parallelism that surpasses that of CPUs and there are much less applications capable of solving CSPs on GPUs, leaving space for further improvement. This paper describes work in progress in the solving of CSPs on GPUs, CPUs and other devices, such as Intel Many Integrated Cores (MICs), in parallel. It presents the gains obtained when applying more devices to solve some problems and the main challenges that must be faced when using devices with as different architectures as CPUs and GPUs, with a greater focus on how to effectively achieve good load balancing between such heterogeneous devices.

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A High-Performance Computing job dispatcher is a critical software that assigns the finite computing resources to submitted jobs. This resource assignment over time is known as the on-line job dispatching problem in HPC systems. The fact the problem is on-line means that solutions must be computed in real-time, and their required time cannot exceed some threshold to do not affect the normal system functioning. In addition, a job dispatcher must deal with a lot of uncertainty: submission times, the number of requested resources, and duration of jobs. Heuristic-based techniques have been broadly used in HPC systems, at the cost of achieving (sub-)optimal solutions in a short time. However, the scheduling and resource allocation components are separated, thus generates a decoupled decision that may cause a performance loss. Optimization-based techniques are less used for this problem, although they can significantly improve the performance of HPC systems at the expense of higher computation time. Nowadays, HPC systems are being used for modern applications, such as big data analytics and predictive model building, that employ, in general, many short jobs. However, this information is unknown at dispatching time, and job dispatchers need to process large numbers of them quickly while ensuring high Quality-of-Service (QoS) levels. Constraint Programming (CP) has been shown to be an effective approach to tackle job dispatching problems. However, state-of-the-art CP-based job dispatchers are unable to satisfy the challenges of on-line dispatching, such as generate dispatching decisions in a brief period and integrate current and past information of the housing system. Given the previous reasons, we propose CP-based dispatchers that are more suitable for HPC systems running modern applications, generating on-line dispatching decisions in a proper time and are able to make effective use of job duration predictions to improve QoS levels, especially for workloads dominated by short jobs.

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Background Recentemente la letteratura scientifica ha dimostrato come un corretto controllo posturale faciliti i movimenti dell’arto superiore. Ci sono evidenze secondo cui, applicando al paziente dei contenimenti sul tronco, si ha un miglioramento della funzionalità dell’arto superiore. Obiettivi L’obiettivo principale della tesi era quello di verificare come il sostegno del tronco con l’utilizzo di una stabile struttura assiale, attraverso un supporto esterno definito “trunk constraint”, incrementi il controllo posturale, per facilitare i movimenti frazionati degli arti superiori in persone con esiti di patologie neurologiche. Materiali e metodi Il caso clinico riguarda un uomo di 60 anni con esiti di emiparesi sinistra da ictus ischemico destro. E’ stato eseguito un protocollo di dieci sessioni di trattamento, di un’ora ciascuna, in cui veniva applicata la facilitazione attraverso trunk constraint in diversi setting riabilitativi. I dati sono stati raccolti tramite le scale: Trunk Control Test, Trunk Impairment Scale e Fugl-Meyer Assessment. Inoltre, è stata eseguita l’analisi osservazionale, attraverso videoripresa, di un gesto funzionale dell’arto superiore. Risultati I dati rilevati dimostrano degli effetti positivi rispetto alle ipotesi di partenza. Infatti sono stati riscontrati miglioramenti negli item delle scale somministrate e nella valutazione qualitativa dell’arto superiore. In particolare, si è evidenziato un miglioramento nel controllo del tronco nella scala Trunk Control Test e nella Trunk Impairment Scale e della funzione dell’arto superiore alla scala Fugl-Meyer Assessment. L’analisi osservazionale dei video dimostra un miglioramento del timing di attivazione durante la fase di reaching. Conclusioni I risultati ottenuti supportano il fatto che un incremento dell’attività antigravitaria del tronco, anche attraverso supporti esterni come la trunk constraint, possono facilitare un miglioramento funzionale dell’arto superiore.

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Combinatorial decision and optimization problems belong to numerous applications, such as logistics and scheduling, and can be solved with various approaches. Boolean Satisfiability and Constraint Programming solvers are some of the most used ones and their performance is significantly influenced by the model chosen to represent a given problem. This has led to the study of model reformulation methods, one of which is tabulation, that consists in rewriting the expression of a constraint in terms of a table constraint. To apply it, one should identify which constraints can help and which can hinder the solving process. So far this has been performed by hand, for example in MiniZinc, or automatically with manually designed heuristics, in Savile Row. Though, it has been shown that the performances of these heuristics differ across problems and solvers, in some cases helping and in others hindering the solving procedure. However, recent works in the field of combinatorial optimization have shown that Machine Learning (ML) can be increasingly useful in the model reformulation steps. This thesis aims to design a ML approach to identify the instances for which Savile Row’s heuristics should be activated. Additionally, it is possible that the heuristics miss some good tabulation opportunities, so we perform an exploratory analysis for the creation of a ML classifier able to predict whether or not a constraint should be tabulated. The results reached towards the first goal show that a random forest classifier leads to an increase in the performances of 4 different solvers. The experimental results in the second task show that a ML approach could improve the performance of a solver for some problem classes.

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The aim of this paper is to discuss some rhythmic differences between European and Brazilian Portuguese and their relationship to pretonic vowel reduction phenomena. After the basic facts of PE and PB are presented, we show that the issue cannot be discussed without taking into account secondary stress placement, and we proceed to present the algorithm-based approach to secondary stress in Portuguese, representative of Metrical Phonology analyses. After showing that this deterministic approach cannot adequately explain the variable position of secondary stress in both languages regarding words with an even number of pretonic syllables, we argue for the interpretation of secondary stress and therefore for the construction of rhythmic units at the PF interface, as suggested in Chomsky s Minimalist Program. We also propose, inspired by the constrain hierarchies as proposed in Optimality Theory, that such interpretation must take into account two different constraint rankings, in EP and BP. These different rankings would ultimately explain the rhythmic differences between both languages, as well as the different behavior of pretonic vowels with respect to reduction processes.

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Avaliou-se o efeito da castração sobre o desempenho produtivo e sobre as características de carcaça e realizou-se a avaliação econômica de bovinos terminados em pastagens de Brachiaria decumbens. Foram utilizados oito novilhos Canchim-Nelore com 14 meses de idade, sendo quatro animais castrados e quatro não-castrados, com média de peso corporal de 273,2kg. O delineamento foi inteiramente ao acaso com quatro repetições por tratamento. Os animais receberam, diariamente, 0,7% do PC de suplemento proteíco-energético e foram abatidos aos 26 meses de idade. O peso de abate e o ganho médio diário (GMD) diferiram entre castrados e não-castrados, com médias de 441,0 e 482,2kg e 0,6 e 0,7kg/dia, respectivamente. Não houve efeito da castração sobre as características avaliadas, com exceção do peso de abate, do peso da carcaça quente, 252,3 versus 229,9kg, da cor da carne, 3,25 versus 4,50 pontos e da espessura da gordura subcutânea, 0,6 versus 1,4mm, respectivamente, para não-castrados e castrados. A lucratividade por animal e por hectare foi de 14,5 e 15,8% para não-castrados e 4,5 e 5,8% para castrados, respectivamente. Sugere-se a utilização de bovinos não-castrados suplementados em pastagens de Brachiaria decumbens.

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O ácido graxo (AG) é uma importante fonte de energia para o músculo esquelético. Durante o exercício sua mobilização é aumentada para suprir as necessidades da musculatura ativa. Acredita-se que diversos pontos de regulação atuem no controle da oxidação dos AG, sendo o principal a atividade do complexo carnitina palmitoil transferase (CPT), entre os quais três componentes estão envolvidos: a CPT I, a CPT II e carnitina acilcarnitina translocase. A função da CPT I durante o exercício físico é controlar a entrada de AG para o interior da mitocôndria, para posterior oxidação do AG e produção de energia. Em resposta ao treinamento físico há um aumento na atividade e expressão da CPT I no músculo esquelético. Devido sua grande importância no metabolismo de lipídios, os mecanismos que controlam sua atividade e sua expressão gênica são revisados no presente estudo. Reguladores da expressão gênica de proteínas envolvidas no metabolismo de lipídios no músculo esquelético, os receptores ativados por proliferadores de peroxissomas (PPAR) alfa e beta, são discutidos com um enfoque na resposta ao treinamento físico.

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This paper provides a description of the wave climate off the Brazilian coast based on an eleven-year time series (Jan/1997-Dec/2007) obtained from the NWW3 operational model hindcast reanalysis. Information about wave climate in Brazilian waters is very scarce and mainly based on occasional short-term observations, the present analysis being the first covering such temporal and spatial scales. To define the wave climate, six sectors were defined and analyzed along the Brazilian shelf-break: South (W1), Southeast (W2), Central (W3), East (W4), Northeast (W5) and North (W6). W1, W2 and W3 wave regimes are determined by the South Atlantic High (SAH) and the passage of synoptic cold fronts; W4, W5 and W6 are controlled by the Intertropical Convergence Zone (ITCZ) and its meridional oscillation. The most energetic waves are from the S, generated by the strong winds associated to the passage of cold fronts, which mainly affect the southern region. Wave power presents a decrease in energy levels from south to north, with its annual variation showing that the winter months are the most energetic in W1 to W4, while in W5 and W6 the most energetic conditions occur during the austral summer. The information presented here provides boundary conditions for studies related to coastal processes, fundamental for a better understanding of the Brazilian coastal zone.

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A glutamina é o aminoácido livre mais abundante no sangue e no músculo esquelético, bem como é o principal substrato energético para células de elevado turnover, como enterócitos e leucócitos. Adicionalmente, a glutamina representa o principal aminoácido transferido para o feto pela placenta e, juntamente com o glutamato, constituem os aminoácidos mais abundantes no leite materno. Todavia, bebês nascidos prematuramente sofrem interrupção abrupta do fornecimento placentário de glutamina, o que acarreta em dependência exclusiva da síntese endógena ou do fornecimento exógeno deste aminoácido. Aliado a isso, neonatos pré-termo (PT) e com baixo peso ao nascer (BPN), freqüentemente, recebem apenas nutrição parenteral total nas primeiras semanas de vida, a qual não contém glutamina. Cabe ainda destacar que esses bebês possuem pouca massa muscular e, portanto, seus estoques de glutamina são limitados. Uma vez que neonatos PT e com BPN estão sujeitos a intenso crescimento e a inúmeros estresses fisiológicos, é possível que a glutamina seja um nutriente condicionalmente essencial nessa fase da vida, fato que estimulou a realização de estudos com a finalidade de avaliar os possíveis benefícios clínicos da suplementação enteral e parenteral com glutamina em neonatos PT e com BPN.