769 resultados para Gansfort, Wessel, 1419-1489.
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This paper considers the optimal design of fabricated steel beams for long-span portal frames. The design optimisation takes into account ultimate as well as serviceability limit states, adopting deflection limits recommended by the Steel Construction Institute (SCI). Results for three benchmark frames demonstrate the efficiency of the optimisation methodology. A genetic algorithm (GA) was used to optimise the dimensions of the plates used for the columns, rafters and haunches. Discrete decision variables were adopted for the thickness of the steel plates and continuous variables for the breadth and depth of the plates. Strategies were developed to enhance the performance of the GA including solution space reduction and a hybrid initial population half of which is derived using Latin hypercube sampling. The results show that the proposed GA-based optimisation model generates optimal and near-optimal solutions consistently. A parametric study is then conducted on frames of different spans. A significant variation in weight between fabricated and conventional hot-rolled steel portal frames is shown; for a 50 m span frame, a 14–19% saving in weight was achieved. Furthermore, since Universal Beam sections in the UK come from a discrete section library, the results could also provide overall dimensions of other beams that could be more efficient for portal frames. Eurocode 3 was used for illustrative purposes; any alternative code of practice may be used.
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Background: The oral cavity is a frontline barrier which is often exposed to physical trauma and noxious substances, leading to pro-inflammatory responses designed to be protective in nature. The transient receptor potential (TRP) super family of ion channels is believed to play a critical role in sensory physiology, acting as transducers for thermal, mechanical and chemical stimuli. Our understanding of the role of TRP channel activation in gingival and periodontal inflammation is currently limited. Gingival fibroblasts are the most abundant structural cell in periodontal tissues and we hypothesised that they may have a role in the inflammatory response associated with TRP channel activation. Objectives: The present study was designed to determine whether the TRPV1 agonist capsaicin could elicit a pro-inflammatory response in gingival fibroblasts in vitro by up-regulation of interleukin-8 (IL-8) production. Methods: Gingival fibroblasts were derived by explant culture from surgical tissues following ethical approval. Cells were maintained in Dulbecco's modified Eagle's medium (DMEM), containing 10% fetal calf serum (FCS) in 5% CO2. Following treatment of gingival fibroblasts with capsaicin, IL-8 levels were measured by ELISA. The potential cytotoxicity of capsaicin was determined by the MTT assay. Results: In gingival fibroblasts treated with the TRPV1 agonist capsaicin (10µM), IL-8 production was significantly increased compared with untreated control cells. Capsaicin was shown not to be toxic to gingival fibroblasts at the concentrations studied. Conclusion: The identification of factors that modulate pro-inflammatory cytokine production is important for our understanding of gingival and periodontal inflammation. This study reports for the first time that gingival fibroblasts respond to the TRPV1 agonist capsaicin by increased production of IL-8. Activation of TRPV1 on gingival fibroblasts could therefore have an important role in initiating and sustaining the inflammatory response associated with periodontal diseases
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O texto propõe uma problematização da experiência turística contemporânea, a partir de eixos operatórios reconfiguradores do seu carácter fragmentário. Toma o fenómeno turístico como prática intercultural historicamente determinada, interpelando-o face à experiência moderna, para procurar compreender as suas possibilidades e limites, no confronto com a crise da racionalidade própria da Modernidade.
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Dissertação de mest. em energias renováveis e Gestão da Energia. Instituto Superior de Engenharia,Univ. do Algarve, 2011
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Tese de mestrado, Estudos Românicos (Cultura Portuguesa), Universidade de Lisboa, Faculdade de Letras, 2011
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In recent years the use of several new resources in power systems, such as distributed generation, demand response and more recently electric vehicles, has significantly increased. Power systems aim at lowering operational costs, requiring an adequate energy resources management. In this context, load consumption management plays an important role, being necessary to use optimization strategies to adjust the consumption to the supply profile. These optimization strategies can be integrated in demand response programs. The control of the energy consumption of an intelligent house has the objective of optimizing the load consumption. This paper presents a genetic algorithm approach to manage the consumption of a residential house making use of a SCADA system developed by the authors. Consumption management is done reducing or curtailing loads to keep the power consumption in, or below, a specified energy consumption limit. This limit is determined according to the consumer strategy and taking into account the renewable based micro generation, energy price, supplier solicitations, and consumers’ preferences. The proposed approach is compared with a mixed integer non-linear approach.
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This paper addresses the problem of Biological Inspired Optimization Techniques (BIT) parameterization, considering the importance of this issue in the design of BIT especially when considering real world situations, subject to external perturbations. A learning module with the objective to permit a Multi-Agent Scheduling System to automatically select a Meta-heuristic and its parameterization to use in the optimization process is proposed. For the learning process, Casebased Reasoning was used, allowing the system to learn from experience, in the resolution of similar problems. Analyzing the obtained results we conclude about the advantages of its use.
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The neuronal-specific cholesterol 24S-hydroxylase (CYP46A1) is important for brain cholesterol elimination. Cyp46a1 null mice exhibit severe deficiencies in learning and hippocampal long-term potentiation, suggested to be caused by a decrease in isoprenoid intermediates of the mevalonate pathway. Conversely, transgenic mice overexpressing CYP46A1 show an improved cognitive function. These results raised the question of whether CYP46A1 expression can modulate the activity of proteins that are crucial for neuronal function, namely of isoprenylated small guanosine triphosphate-binding proteins (sGTPases). Our results show that CYP46A1 overexpression in SH-SY5Y neuroblastoma cells and in primary cultures of rat cortical neurons leads to an increase in 3-hydroxy-3-methyl-glutaryl-CoA reductase activity and to an overall increase in membrane levels of RhoA, Rac1, Cdc42 and Rab8. This increase is accompanied by a specific increase in RhoA activation. Interestingly, treatment with lovastatin or a geranylgeranyltransferase-I inhibitor abolished the CYP46A1 effect. The CYP46A1-mediated increase in sGTPases membrane abundance was confirmed in vivo, in membrane fractions obtained from transgenic mice overexpressing this enzyme. Moreover, CYP46A1 overexpression leads to a decrease in the liver X receptor (LXR) transcriptional activity and in the mRNA levels of ATP-binding cassette transporter 1, sub-family A, member 1 and apolipoprotein E. This effect was abolished by inhibition of prenylation or by co-transfection of a RhoA dominant-negative mutant. Our results suggest a novel regulatory axis in neurons; under conditions of membrane cholesterol reduction by increased CYP46A1 expression, neurons increase isoprenoid synthesis and sGTPase prenylation. This leads to a reduction in LXR activity, and consequently to a decrease in the expression of LXR target genes.
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Aspirin is recommended as a lifelong therapy that should never be interrupted for patients with cardiovascular dis- ease. Clopidogrel therapy is mandatory for six weeks after placement of bare-metal stents, three to six months after myocardial infarction, and at least 12 months after placement of drug-eluting stents. Because of the hypercoagulable state induced by surgery, early withdrawal of antiplatelet therapy for secondary prevention of cardiovascular disease increases the risk of postoperative myocardial infarction and death five- to 10-fold in stented patients who are on continuous dual antiplatelet therapy. The shorter the time between revascularization and surgery, the higher the risk of adverse cardiac events. Elective surgery should be postponed beyond these periods, whereas vital, semiurgent, or urgent operations should be performed under continued dual antiplatelet therapy. The risk of surgical hemorrhage is increased approximately 20 percent by aspirin or clopidogrel alone, and 50 percent by dual antiplatelet therapy. The present clinical data suggest that the risk of a cardiovascular event when stopping antiplatelet agents preoperatively is higher than the risk of surgical bleeding when continuing these drugs, except during surgery in a closed space (e.g., intracranial, posterior eye chamber) or surgeries associated with massive bleeding and difficult hemostasis.
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In the context of an autologous cell transplantation study, a unilateral biopsy of cortical tissue was surgically performed from the right dorsolateral prefrontal cortex (dlPFC) in two intact adult macaque monkeys (dlPFC lesioned group), together with the implantation of a chronic chamber providing access to the left motor cortex. Three other monkeys were subjected to the same chronic chamber implantation, but without dlPFC biopsy (control group). All monkeys were initially trained to perform sequential manual dexterity tasks, requiring precision grip. The motor performance and the prehension's sequence (temporal order to grasp pellets from different spatial locations) were analysed for each hand. Following the surgery, transient and moderate deficits of manual dexterity per se occurred in both groups, indicating that they were not due to the dlPFC lesion (most likely related to the recording chamber implantation and/or general anaesthesia/medication). In contrast, changes of motor habit were observed for the sequential order of grasping in the two monkeys with dlPFC lesion only. The changes were more prominent in the monkey subjected to the largest lesion, supporting the notion of a specific effect of the dlPFC lesion on the motor habit of the monkeys. These observations are reminiscent of previous studies using conditional tasks with delay that have proposed a specialization of the dlPFC for visuo-spatial working memory, except that this is in a different context of "free-will", non-conditional manual dexterity task, without a component of working memory.
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En otoño de 1997 se realizó un crucero de evaluación del recurso merluza (Merluccius gayi peruanus), con el objetivo de conocer su estructura poblacional y su biomasa. El recurso se encontró distribuido más allá de lo normal, debido al desarrollo de un evento El Niño. La población era predominantemente joven con el 80% de ejemplares por debajo de la talla mínima de captura (35 cm de longitud total). Se encontraron ejemplares entre los 1 y 12 años de edad, siendo notoria la presencia frecuente de ejemplares longevos, que no se observaban en los últimos años. La biomasa se estimó en el orden de las 250 mil a 300 mil toneladas. Se encontraron fuertes evidencias sobre la existencia de dos sub-unidades poblacionales o stocks.
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Pohjois-Savon YTY on Euroopan Sosiaalirahaston (ESR) osittain rahoittama projekti, jossa koulutetaan ja työllistetään työttömänä olleita henkilöitä ympäristön kunnostustöihin. Projektin tavoitteena on vahvistaa työttömänä olleiden henkilöiden työkykyä ja työllistymismahdollisuuksia sekä edistää ympäristön kunnostamista. Projekti käynnistyi 1.3.2008 ja vuonna 2010 mukana oli 17 kuntaa: Iisalmi, Juankoski, Kaavi, Karttula, Kiuruvesi, Leppävirta, Nilsiä, Pielavesi, Rautalampi, Rautavaara, Siilinjärvi, Sonkajärvi, Suonenjoki, Tervo, Tuusniemi, Vesanto ja Vieremä. Projektiin liittyvä koulutus toteutettiin työvoimakoulutuksena samanaikaisesti Iisalmessa, Juankoskella ja Suonenjoella. Koulutuksen aikana osallistujat suorittivat työssä tarvittavat kortit: työturvallisuus-, tulityö-, ensiapu 1- ja tieturva 1 -kortit. Lisäksi koulutuksen aikana saatiin tietoa mm. reittirakentamisesta, rakennusten kunnostamisesta sekä työvälineiden huollosta. Koulutusjakson jälkeen alkoi kuuden kuukauden työjakso kunnissa. Kunnat toimivat työnantajina ja osoittivat työkohteet. Projektin työnsuunnittelijat ohjasivat ja opastivat työllistettyjä työkohteissa työmenetelmiin ja työtapoihin liittyvissä kysymyksissä kannustaen samalla jatkotyöllistymiseen ja/tai kouluttautumiseen. Projektissa aloitti 86 henkilöä vuonna 2010. Henkilötyöpäiviä kertyi yhteensä 12761, joista ohjaus-ja konsultointipäiviä oli 18 ja koulutuspäiviä 1419. Julkaisussa esitetään yleiskatsaus projektin toimintaan vuonna 2010 ja esitellään kunnissa toteutettuja työkohteita.