927 resultados para timing constraint


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Pre-reperfusion administration of intravenous (IV) metoprolol reduces infarct size in ST-segment elevation myocardial infarction (STEMI). This study sought to determine how this cardioprotective effect is influenced by the timing of metoprolol therapy having either a long or short metoprolol bolus-to-reperfusion interval. We performed a post hoc analysis of the METOCARD-CNIC (effect of METOprolol of CARDioproteCtioN during an acute myocardial InfarCtion) trial, which randomized anterior STEMI patients to IV metoprolol or control before mechanical reperfusion. Treated patients were divided into short- and long-interval groups, split by the median time from 15 mg metoprolol bolus to reperfusion. We also performed a controlled validation study in 51 pigs subjected to 45 min ischemia/reperfusion. Pigs were allocated to IV metoprolol with a long (−25 min) or short (−5 min) pre-perfusion interval, IV metoprolol post-reperfusion (+60 min), or IV vehicle. Cardiac magnetic resonance (CMR) was performed in the acute and chronic phases in both clinical and experimental settings. For 218 patients (105 receiving IV metoprolol), the median time from 15 mg metoprolol bolus to reperfusion was 53 min. Compared with patients in the short-interval group, those with longer metoprolol exposure had smaller infarcts (22.9 g vs. 28.1 g; p = 0.06) and higher left ventricular ejection fraction (LVEF) (48.3% vs. 43.9%; p = 0.019) on day 5 CMR. These differences occurred despite total ischemic time being significantly longer in the long-interval group (214 min vs. 160 min; p < 0.001). There was no between-group difference in the time from symptom onset to metoprolol bolus. In the animal study, the long-interval group (IV metoprolol 25 min before reperfusion) had the smallest infarcts (day 7 CMR) and highest long-term LVEF (day 45 CMR). In anterior STEMI patients undergoing primary angioplasty, the sooner IV metoprolol is administered in the course of infarction, the smaller the infarct and the higher the LVEF. These hypothesis-generating clinical data are supported by a dedicated experimental large animal study.

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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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The aim of this thesis was to quantify experimentally in the field the effects of different timing regimes of hypoxia on the structure of benthic communities in a transitional habitat. The experiment was performed from 8 July to 29 July 2019 in a shallow subtidal area in Pialassa Baiona (Italy), a lagoon characterized by mixing regimes dominated by the tide. The benthic community was isolated using cylinders 15,5Cm x 20Cm size. Hypoxic conditions were imposed by covering the treated cylinders with a black plastic bag while control cylinders were left uncovered. We created 4 different timing regimes of hypoxia by manipulating both the duration of hypoxia (4 or 8 days) as well as the ratio between the duration of subsequent periods of hypoxia and the duration of a normoxic period between subsequent hypoxic events (D4R3/2, D8R3/2). At the end of each experimental trial, the benthic communities within each pot were retrieved, sieved in the field and subsequent analyzed in the laboratory where organisms were identified and counted. Results showed that benthic organism were generally negatively affected by hypoxic stress events. As expected, longer hypoxic events caused a stronger decrease of benthic community abundance. When the hypoxic events were interrupted by the normoxic event there were two different results. If the hypoxic period was too long, the normoxic period didn’t cause a positive recovery effect, and further decline of the benthic community was observed. Conversely normoxia had positive effects if the period of hypoxia was short enough not to compromise the benthic community. This resulted in a statistically significant interaction between the tested factors Duration and Ratio. Amphipods were the most sensitive organisms to hypoxia. We conclude that the effects of hypoxia can be greatly relieved by short normoxic periods if they happen frequently enough.

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Lo studio che verrà presentato in questo lavoro di tesi riguarda la caratterizzazione di Silicon PhotoMultiplier (SiPM): essi sono sensori a semiconduttore che sono stati proposti per la realizzazione del layer Time-Of-Flight (TOF) del nuovo esperimento proposto ad LHC, ALICE 3. Sono stati testati sensori diversi, sia in termini di casa di fabbricazione (FBK o HPK), sia in termini di struttura; in particolare, i modelli a disposizione di produzione FBK sono singoli SPAD, singoli SiPM e mini-array di SiPM, mentre i modelli HPK sono tutti singoli SiPM. La caratterizzazione è avvenuta mediante misure di corrente e capacità del sensore al variare della tensione (curve IV e curve CV); l'obiettivo primario è studiare e confrontare tali andamenti, in modo da poter selezionare i sensori con caratteristiche simili per la costruzione del layer del TOF. Si è osservato che sensori della stessa casa produttrice e con la stessa struttura interna esibiscono comportamenti quasi sovrapponibili, dimostrando in generale una ottima uniformità.

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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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Universidade Estadual de Campinas . Faculdade de Educação Física

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OBJETIVO: o objetivo deste trabalho foi estudar as consequências da lesão por contusão da medula espinhal, associada ao estreitamento do canal vertebral, no comportamento motor de ratos, avaliando-se o efeito do tempo para descompressão na recuperação neurológica dos animais. MÉTODOS: foram utilizados ratos Wistar machos (n=6 por grupo), subdivididos nos seguintes grupos experimentais: laminectomia (T9-T10, Grupo Controle), contusão por queda de peso (10 g de peso, 15 cm de altura), estreitamento do canal vertebral em 35% (hastes de policarbonato; espessura de 0,78 mm) e contusão associada ao estreitamento do canal vertebral. O grupo de lesão associada foi ainda subdividido em sem ou com descompressão 24 ou 72 horas após a cirurgia. Os animais foram sacrificados sete dias após os procedimentos cirúrgicos. A função locomotora dos animais foi avaliada por meio do teste do campo aberto, do teste do plano inclinado e pela aplicação da escala BBB, antes da cirurgia, 24 e 72 horas depois da cirurgia e após 7 dias do procedimento cirúrgico. RESULTADOS: a lesão por queda de peso e compressão da medula espinhal, bem como a lesão mista, prejudicaram o comportamento motor dos animais, sendo que a descompressão cirúrgica após 24 e 72 horas da cirurgia não melhorou a recuperação motora dos animais, como mostram os resultados da avaliação de campo aberto, no plano inclinado e pela escala BBB. Por outro lado, os animais que sofreram lesão medular por queda de peso apresentaram melhores escores na escala BBB e ângulos maiores no plano inclinado do que aqueles que sofreram lesão por estreitamento do canal vertebral ou lesão mista. CONCLUSÕES: a lesão por queda de peso ou estreitamento do canal vertebral provocou alterações no comportamento motor dos animais, sendo que a descompressão não trouxe melhora funcional significativa.

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During development, children become capable of categorically associating stimuli and of using these relationships for memory recall. Brain damage in childhood can interfere with this development. This study investigated categorical association of stimuli and recall in four children with brain damages. The etiology, topography and timing of the lesions were diverse. Tasks included naming and immediate recall of 30 perceptually and semantically related figures, free sorting, delayed recall, and cued recall of the same material. Traditional neuropsychological tests were also employed. Two children with brain damage sustained in middle childhood relied on perceptual rather than on categorical associations in making associations between figures and showed deficits in delayed or cued recall, in contrast to those with perinatal lesions. One child exhibited normal performance in recall despite categorical association deficits. The present results suggest that brain damaged children show deficits in categorization and recall that are not usually identified in traditional neuropsychological tests.

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PURPOSE: To study were to reproduce an alveolar bone defect model in Wistar rats to be used for testing the efficacy of stem cell therapies. Additionally, we also aimed to determine the osteogenesis process of this osseous defect in the 1 month period post-surgery. METHODS: The animals were randomly divided into two groups of 7 animals each. A gingivobuccal incision was made, and a bone defect of 28 mm² of area was performed in the alveolar region. Animals were killed at 2 weeks after surgery (n=7) and 4 weeks after surgery (n=7). RESULTS: The average area of the alveolar defect at time point of 2 weeks was 22.27 ± 1.31 mm² and the average area of alveolar defect at time point of 4 weeks was 9.03 ± 1.17 mm². The average amount of bone formation at time point of 2 weeks was 5.73 ± 1.31 mm² and the average amount of bone formation at time point of 4 weeks was 19 ± 1.17 mm². Statistically significant differences between the amount of bone formation at 2 weeks and 4 weeks after surgery were seen (p=0.003). CONCLUSION: The highest rate of ossification occurred mostly from 2 to 4 weeks after surgery. This observation suggests that 4 weeks after the bone defect creation should be a satisfactory timing to assess the potential of bone inductive stem cells to accelerate bone regeneration in Wistar rats.

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Modelos teóricos inspirados na teoria da história de vida têm avaliado padrões de reprodução humanos em países desenvolvidos, com resultados ainda não conclusivos. Em vista das condições de vida na população brasileira, foram investigadas relações entre marcos da carreira reprodutiva feminina, condições ambientais e variáveis psicossociais relacionadas às condições de criação. Foram entrevistadas 606 mulheres em seis estados. Os resultados apóiam a teoria da história de vida, mostrando associações entre condições de vida na infância e início da vida sexual e da reprodução, mas não com a idade da menarca. Sugerimos que diferentes marcadores da vida reprodutiva podem estar sob controle de diferentes fenômenos e que a diversidade de condições da população brasileira oferece contextos alternativos para testar hipóteses.