973 resultados para protocollo TCP, protocollo UDP, Westwood, SACK


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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Em países de clima tropical, o calor é um dos principais limitantes à produção de frangos de corte, sendo ainda responsável por induzir uma elevada mortalidade, especialmente na fase de terminação. Visando aliviar o efeito do estresse pelo calor, foram avaliadas duas técnicas para melhorar a tolerância térmica: o condicionamento térmico precoce (TCP) e a formulação dieta utilizando o princípio de Mongin (equilíbrio eletrolítico). Para tanto, o balanço eletrolítico do K+Na-Cl foi ajustado em 350 mEq/kg e a relação eletrolítica (K+Cl)/Na em 3:1, pelo programa PPFR (http://www.fmva.unesp.br/ppfr). Foram utilizados 300 pintos machos Cobb 500, em arranjo fatorial 2x2 (com e sem TCP e com e sem o princípio de Mongin), num delineamento inteiramente casualizado, em 24 boxes (6 repetições por tratamento). As aves foram inicialmente alojadas em baterias metálicas (1-7 dias de idade), e posteriormente em piso (8-48 dias de idade), sendo arraçoadas com: (T1) dieta tradicional sem TCP; (T2) dieta tradicional com TCP; (T3) dieta com a aplicação do equilíbrio eletrolítico sem TCP e (T4) dieta com aplicação do equilíbrio eletrolítico com TCP. O condicionamento térmico foi realizado no quinto dia de idade, por 24 horas a 36 °C, somente na metade do lote (150 aves). Após esse período, todas as aves foram transferidas para boxes de 1,5x3m (12 aves/boxe), tendo como cama a maravalha de madeira reutilizada. Aos 36 dias de idade foi aplicado um estresse agudo (36°C) por 8 horas em todos os tratamentos, sendo monitorado eletronicamente a temperatura e a umidade do galpão e do microclima na altura das aves. A alimentação e a água foram ad libitum, mesmo durante o período de estresse. Foram aferidos os dados de desempenho aos 7, 35 e 48 dias de idade para ganho de peso, consumo de ração e conversão alimentar, e também a taxa de mortalidade de cada boxe. Verificou-se que tanto o equilíbrio eletrolítico como o condicionamento térmico precoce foram eficazes significativamente (P<0,05) para minimizar a mortalidade dos frangos submetidos ao estresse agudo de calor, sem prejuízo no desempenho das aves. Além disso, foi observado um efeito mais favorável quando aplicados simultaneamente (T4). Assim, para o tratamento em que nenhuma destas estratégias foram utilizadas (T1), a taxa de mortalidade foi 83% superior ao tratamento em que ambas foram aplicadas (T4). Assim, tanto o condicionamento térmico precoce como o princípio de Mongin foram válidos para minimizar os efeitos danosos causados pelo calor em frangos de corte.

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As more reliance is placed on computing and networking systems, the need for redundancy increases. The Common Address Redundancy Protocol (CARP) protocol and OpenBSD’s pfsync utility provide a means by which to implement redundant routers and firewalls. This paper details how CARP and pfsync work together to provide this redundancy and explores the performance one can expect from the open source solutions. Two experiments were run: one showing the relationship between firewall state creation and state synchronization traffic and the other showing how TCP sessions are transparently maintained in the event of a router failure. Discussion of these simulations along with background information gives an overview of how OpenBSD, CARP, and pfsync can provide redundant routers and firewalls for today’s Internet.

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Fibrous materials have morphological similarities to natural cartilage extracellular matrix and have been considered as candidate for bone tissue engineering scaffolds. In this study, we have evaluated a novel electrospun chitosan mat composed of oriented sub-micron fibers for its tensile property and biocompatibility with chondrocytes (cell attachment, proliferation and viability). Scanning electronic microscope images showed the fibers in the electrospun chitosan mats were indeed aligned and there was a slight cross-linking between the parent fibers. The electrospun mats have significantly higher elastic modulus (2.25 MPa) than the cast films (1.19 MPa). Viability of cells on the electrospun mat was 69% of the cells on tissue-culture polystyrene (TCP control) after three days in culture, which was slightly higher than that on the cast films (63% of the TCP control). Cells on the electrospun mat grew slowly the first week but the growth rate increased after that. By day 10, cell number on the electrospun mat was almost 82% that of TCP control, which was higher than that of cast films (56% of TCP). The electrospun chitosan mats have a higher Young’s modulus (P <0.01) than cast films and provide good chondrocyte biocompatibility. The electrospun chitosan mats, thus, have the potential to be further processed into three-dimensional scaffolds for cartilage tissue repair.

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Diurnal Lepidoptera tend to have colorful and conspicuous wing patterns, which is the reason the first classifications of day-flying moths and butterflies were based mainly on wing color and pattern characters. This is the case with the Neotropical Castniidae, which are usually large and colorful day-flying moths. One classification listed 134 species in 32 genera while an alternate classification recognized 81 species. In this paper we examine the taxonomic structure of the genus Hista Oiticica. It is the purpose of this paper to evaluate taxonomically useful characters besides wing pattern with the goal of classifying the taxa of Hista rather than classifying the variation of its wing pattern. In so doing, the results resolve the differences between the two proposed classifications of Hista. In addition, a lectotype is designated for Castnia boisduvalii Walker, 1854 (new synonym of Castnia fabricii Swainson, 1823) to ensure the stability of the name. Other new synonyms are proposed for C. fabricii (C. papagaya Westwood, 1877) and Castnia hegemon Kollar, 1839 (C. menetriesi Boisduval, [1875] and C. hegemon variegata Rothschild, 1919).

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Nicotinic acetylcholine receptors (nAChRs) have been studied in detail with regard to their interaction with therapeutic and drug addiction-related compounds. Using a structureactivity approach, we have examined the relationship among the molecular features of a set of eight para-R-substituted N,N-[(dimethylamino)ethyl] benzoate hydrochlorides, structurally related to procaine and their affinity for the a3 beta 4 nAChR heterologously expressed in KXa3 beta 4R2 cells. Affinity values (log[1/IC50]) of these compounds for the a3 beta 4 nAChR were determined by their competition with [3H]TCP binding. Log(1/IC50) values were analyzed considering different hydrophobic and electronic parameters and those related to molar refractivity. These have been experimentally determined or were taken from published literature. In accordance with literature observations, the generated cross-validated quantitative structureactivity relationship (QSAR) equations indicated a significant contribution of hydrophobic term to binding affinity of procaine analogs to the receptor and predicted affinity values for several local anesthetics (LAs) sets taken from the literature. The predicted values by using the QSAR model correlated well with the published values both for neuronal and for electroplaque nAChRs. Our work also reveals the general structure features of LAs that are important for interaction with nAChRs as well as the structural modifications that could be made to enhance binding affinity. (c) 2012 Wiley Periodicals, Inc.

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The saccadic paradigm has been used to investigate specific cortical networks involving visuospatial attention. We examined whether asymmetry in theta and beta band differentiates the role of the hemispheres during the execution of two different prosacadic conditions: a fixed condition, where the stimulus was presented at the same location; and a random condition, where the stimulus was unpredictable. Twelve healthy volunteers (3 male; mean age: 26.25) performed the task while their brain activity pattern was recorded using quantitative electroencephalography. We did not find any significant difference for beta, slow- and fast-alpha frequencies for the pairs of electrodes analyzed. The results for theta band showed a superiority of the left hemisphere in the frontal region when responding to the random condition on the right, which is related to the planning and selection of responses, and also a greater activation of the right hemisphere during the random condition, in the occipital region, related to the identification and recognition of patterns. These results indicate that asymmetries in the premotor area and the occipital cortex differentiate memory- and stimulus-driven tasks. (C) 2011 Elsevier Inc. All rights reserved.

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This study aimed at analyzing the relationship between slow- and fast-alpha asymmetry within frontal cortex and the planning, execution and voluntary control of saccadic eye movements (SEM), and quantitative electroencephalography (qEEG) was recorded using a 20-channel EEG system in 12 healthy participants performing a fixed (i.e., memory-driven) and a random SEM (i.e., stimulus-driven) condition. We find main effects for SEM condition in slow- and fast-alpha asymmetry at electrodes F3-F4, which are located over premotor cortex, specifically a negative asymmetry between conditions. When analyzing electrodes F7-F8, which are located over prefrontal cortex, we found a main effect for condition in slow-alpha asymmetry, particularly a positive asymmetry between conditions. In conclusion, the present approach supports the association of slow- and fast-alpha bands with the planning and preparation of SEM, and the specific role of these sub-bands for both, the attention network and the coordination and integration of sensory information with a (oculo)-motor response. (C) 2011 Elsevier B.V. All rights reserved.

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This work aims to evaluate the cytocompatibility of injectable and moldable restorative biomaterials based on granules of dense or porous biphasic calcium phosphates (BCPs) with human primary mesenchymal cells, in order to validate them as tools for stem cell-induced bone regeneration. Porous hydroxyapatite (HA) and HA/beta-tricalcium phosphate (beta-TCP) (60: 40) granules were obtained by the addition of wax spheres and pressing at 20 MPa, while dense materials were compacted by pressing at 100 MPa, followed by thermal treatment (1100 degrees C), grinding, and sieving. Extracts were prepared by 24-h incubation of granules on culture media, with subsequent exposition of human primary mesenchymal cells. Three different cell viability parameters were evaluated on the same samples. Scanning electron microscopy analysis of the granules revealed distinct dense and porous surfaces. After cell exposition to extracts, no significant differences on mitochondrial activity (2,3-bis(2-methoxy-4-nitro-5-sulfophenly)-5-[(phenylamino) carbonyl]-2H-tetrazolium hydroxide) or cell density (Crystal Violet Dye Elution) were observed among groups. However, Neutral Red assay revealed that dense materials extracts induced lower levels of total viable cells to porous HA/beta-TCP (P < 0.01). Calcium ion content was also significantly lower on the extracts of dense samples. Porogenic treatments on BCP composites do not affect cytocompatibility, as measured by three different parameters, indicating that these ceramics are well suited for further studies on future bioengineering applications.

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Introduction: The saccadic paradigm has been used to investigate specific cortical networks involving attention. The behavioral and electrophysiological investigations of the SEM contribute significantly to the understanding of attentive patterns presented of neurological and psychiatric disorders and sports performance. Objective: The current study aimed to investigate absolute alpha power changes in sensorimotor brain regions and the frontal eye fields during the execution of a saccadic task. Methods: Twelve healthy volunteers (mean age: 26.25; SD: +/- 4.13) performed a saccadic task while the electroencephalographic signal was simultaneously recorded for the cerebral cortex electrodes. The participants were instructed to follow the LEDs with their eyes, being submitted to two different task conditions: a fixed pattern versus a random pattern. Results: We found a moment main effect for the C3, C4, F3 and F4 electrodes and a condition main effect for the F3 electrode. We also found interaction between factor conditions and frontal electrodes. Conclusions: We conclude that absolute alpha power in the left frontal cortex discriminates the execution of the two stimulus presentation patterns during SEM. (C) 2012 Elsevier Ireland Ltd. All rights reserved.

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Oligoryzomys (Cricetidae, Sigmodontinae) is a common rodent genus from South America that includes a couple of very similar species. Related species have been used as experimental model for understanding several diseases for which these species are reservoirs. In order to provide a better understanding of the embryological aspects of this group, herein we showed data on the embryonic and fetal development in Oligoryzomys sp. Eight specimens of different stages of gestation were obtained from the Collection of the Zoology Museum of University of Sao Paulo, Brazil. Gestational ages were estimated by crown-rump-length according to Evans and Sack (1973). To address our analysis after examining the gross morphology, tissues from several organs were processed for light and scanning electron microscopy. Morphological data on the systems (nervous system, cardiorespiratory system, intestinal tract and urogenital system) were described in detail. Finally, the findings were compared with what is known about embryological aspects in other rodent species in order to establish similarities and differences during the organogenesis in different species.

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Uridine adenosine tetraphosphate (Up(4)A) has been recently identified as a novel and potent endothelium-derived contracting factor and contains both purine and pyrimidine moieties, which activate purinergic P2X and P2Y receptors. The present study was designed to compare contractile responses to Up(4)A and other nucleotides such as ATP (P2X/P2Y agonist), UTP (P2Y(2)/P2Y(4) agonist), UDP (P2Y(6) agonist), and alpha,beta-methylene ATP (P2X(1) agonist) in different vascular regions [thoracic aorta, basilar, small mesenteric, and femoral arteries] from deoxycorticosterone acetate-salt (DOCA-salt) and control rats. In DOCA-salt rats [vs. control uninephrectomized (Uni) rats]: (1) in thoracic aorta, Up(4)A-, ATP-, and UP-induced contractions were unchanged; (2) in basilar artery, Up(4)A-, ATP-, UTP- and UDP-induced contractions were increased, and expression for P2X(1), but not P2Y(2) or P2Y(6) was decreased; (3) in small mesenteric artery, Up(4)A-induced contraction was decreased and UDP-induced contraction was increased; expression of P2Y(2) and P2X(1) was decreased whereas P2Y(6) expression was increased; (4) in femoral artery, Up(4)A-. UTP-, and UDP-induced contractions were increased, but expression of P2Y(2), P2Y(6) and P2X(1) was unchanged. The alpha,beta-methylene ATP-induced contraction was bell-shaped and the maximal contraction was reached at a lower concentration in basilar and mesenteric arteries from Uni rats, compared to arteries from DOCA-salt rats. These results suggest that Up(4)A-induced contraction is heterogenously affected among various vascular beds in arterial hypertension. P2Y receptor activation may contribute to enhancement of Up(4)A-induced contraction in basilar and femoral arteries. These changes in vascular reactivity to Up(4)A may be adaptive to the vascular alterations produced by hypertension. (C) 2011 Elsevier Ltd. All rights reserved.

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Abstract Background Some organisms can survive extreme desiccation by entering a state of suspended animation known as anhydrobiosis. The free-living mycophagous nematode Aphelenchus avenae can be induced to enter anhydrobiosis by pre-exposure to moderate reductions in relative humidity (RH) prior to extreme desiccation. This preconditioning phase is thought to allow modification of the transcriptome by activation of genes required for desiccation tolerance. Results To identify such genes, a panel of expressed sequence tags (ESTs) enriched for sequences upregulated in A. avenae during preconditioning was created. A subset of 30 genes with significant matches in databases, together with a number of apparently novel sequences, were chosen for further study. Several of the recognisable genes are associated with water stress, encoding, for example, two new hydrophilic proteins related to the late embryogenesis abundant (LEA) protein family. Expression studies confirmed EST panel members to be upregulated by evaporative water loss, and the majority of genes was also induced by osmotic stress and cold, but rather fewer by heat. We attempted to use RNA interference (RNAi) to demonstrate the importance of this gene set for anhydrobiosis, but found A. avenae to be recalcitrant with the techniques used. Instead, therefore, we developed a cross-species RNAi procedure using A. avenae sequences in another anhydrobiotic nematode, Panagrolaimus superbus, which is amenable to gene silencing. Of 20 A. avenae ESTs screened, a significant reduction in survival of desiccation in treated P. superbus populations was observed with two sequences, one of which was novel, while the other encoded a glutathione peroxidase. To confirm a role for glutathione peroxidases in anhydrobiosis, RNAi with cognate sequences from P. superbus was performed and was also shown to reduce desiccation tolerance in this species. Conclusions This study has identified and characterised the expression profiles of members of the anhydrobiotic gene set in A. avenae. It also demonstrates the potential of RNAi for the analysis of anhydrobiosis and provides the first genetic data to underline the importance of effective antioxidant systems in metazoan desiccation tolerance.

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Avaliar os efeitos da suplementação oral de L-carnitina associada ao treinamento físico e muscular respiratório na doença pulmonar obstrutiva crônica (DPOC). Participaram 14 voluntários com idade de 65±10,4 anos e diagnóstico clínico de DPOC moderado, classificados de acordo com a espirometria prévia. Os voluntários foram divididos em grupo treino esteira (GTE) e grupo treino muscular respiratório (GTMR). Realizaram o teste de caminhada de seis minutos (TC6'), teste de caminhada com carga progressiva (TCP), avaliação nutricional do índice de massa corpórea (IMC), dose diária recomendada de L-carnitina, pressões inspiratórias (PImáx) e expiratórias máximas (PEmáx). Fizeram 30 min de caminhada em esteira, 3 vezes/semana por 10 semanas, e o GTMR realizou, ainda, 10 min de treinamento muscular inspiratório (Threshold® IMT) e 10 min de treinamento muscular expiratório (Threshold® PEP) à 50% da PImáx e PEmáx ajustados semanalmente. Após 10 semanas, foram reavaliados. No TC6' pré e pós-programa de treinamento físico, as variáveis alteradas foram: distância percorrida (DP), frequência cardíaca (FC) final, pressão arterial sistólica (PAS) final, pressão arterial diastólica (PAD) final e Borg final no GTMR, no GTE as variáveis alteradas foram FC repouso, FC final, PAS final, Borg repouso e DP. Comparando os grupos no TC6, o GTE apresentou FC final, PAD final e Borg final maiores do que o GTMR na reavaliação; já no TCP, a FC final, PAS final, Borg final foram maiores no GTE, e DP foi maior no GTMR. Na avaliação respiratória, a PEmáx foi maior no GTMR na reavaliação. O treino aeróbio e suplementação de L-carnitina na DPOC otimizou a performance, a capacidade física e a tolerância ao esforço.