435 research outputs found

    Design and performance of ropes for climbing and sailing

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    Ropes are an important part of the equipment used by climbers, mountaineers, and sailors. On first inspection, most modern polymer ropes appear similar, and it might be assumed that their designs, construction, and properties are governed by the same requirements. In reality, the properties required of climbing ropes are dominated by the requirement that they effectively absorb and dissipate the energy of the falling climber, in a manner that it does not transmit more than a critical amount of force to his body. This requirement is met by the use of ropes with relatively low longitudinal stiffness. In contrast, most sailing ropes require high stiffness values to maximize their effectiveness and enable sailors to control sails and equipment precisely. These conflicting requirements led to the use of different classes of materials and different construction methods for the two sports. This paper reviews in detail the use of ropes, the properties required, manufacturing techniques and materials utilized, and the effect of service conditions on the performance of ropes. A survey of research that has been carried out in the field reveals what progress has been made in the development of these essential components and identifies where further work may yield benefits in the future

    Network measures in civil air transport: A case study of Lufthansa

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    Network analysis has already a long history in operations research and quantitative social science research. In the past, much attention has been paid to shortest-route algorithms (for example, the travelling salesman problem), where the spatial configuration of networks was put in the centre of empirical investigation. Integer programming, linear and nonlinear programming turned out to offer a proper analytical toolbox. In recent years, we have seen several new trends, in particular, the rise of hub-and-spoke systems in liberalized networks, the emergence of dynamic adjustments to new competitive conditions and the increase in complexity in international networks. Furthermore, it appears that in the past decades many social, spatial and economic systems show an organized pattern characterized by network features, such as transportation, telecommunication, information or energy systems. As a consequence, much attention has recently been paid to the study of network properties emerging in many social, spatial and economic fields, as witnessed by the vast amount of literature published in the past years. Air transport is a prominent example of modern network constellations and will be addressed in this paper from a connectivity perspective. Air transport shows indeed clear network features, which impact on the way single airline carriers operate. The abundant scientific literature on airline networks has addressed this topic in terms of theoretical modelling and empirical measurements on different typologies of airline network configurations. This strand of recent research aimed to measure the network structure in relation to the effects of: (a) the market deregulation in United States in 1978 and in the European Union in the 1990s, (b) new trends in recent airline business strategies denoted as \u2018low cost\u2019 principles. Low cost carriers developed rather fast after the deregulation policy, by acquiring a competitive network advantage on traditional airlines, which consequently seemed to reorganise rapidly their airline network to respond to the new market dynamics. In this context, interesting research has emerged that mainly addressed the issue of describing and classifying networks by means of geographical concentration indices of traffic or flight frequency. These measures, such as the Gini concentration index or the Theil index, provide a proper measure of frequency or traffic concentration of the main airports in a simple, well-organized network. However, if a real-world network structure is complex, including multi-hub or mixed point-to-point and hub-spokes connections, the concentration indices may record high values for all types of structure, but fail to clearly discriminate between different network shapes. There is a need for a more appropriate measurement of connectivity structures in complex networks. Starting from the above considerations and research challenges, the present paper aims to investigate the scientific potential and applicability of a series of network connectivity/concentration indices, in order to properly typify and map out complex airline network configurations. Specifically, these various network indicators will be adopted and tested to describe the main properties \u2013 in terms of the network connectivity and configuration \u2013 of Lufthansa\u2019s airline system

    Beta-lactamic resistance profiles in porphyromonas, prevotella, and parvimonas species isolated from acute endodontic infections

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    Susceptibility to beta-lactamic agents has changed among anaerobic isolates from acute endodontic infections. The aim of the present study was to determine the prevalence of the cfxAlcfxA2 gene in Prevotella spp., Porphyromonas spp., and Parviomonas micra strains and show its phenotypic expression. Root canal samples from teeth with acute endodontic infections were collected and Porphyromonas, Prevotella, and Parvimonas micra strains were isolated and microbiologically identified with conventional culture techniques. The susceptibility of the isolates was determined by the minimum inhibitory concentration of benzylpenicillin, amoxicillin, and amoxicillin + clavulanate using the E-test method (AB BIODISK, Solna, Sweden). The presence of the cfxAlcfxA2 gene was determined through primer-specific polymerase chain reaction. The nitrocefin test was used to determine the expression of the lactamase enzyme. Prevotella disiens, Prevotella oralis, Porphyromonas gin givalis, and P micra strains were susceptible to benzylpenicillin, amoxicillin, and amoxicillin + clavulanate. The cfxA/cfxA2 gene was detected in 2 of 29 isolates (6.9%). Simultaneous detection of the cfxAlcfxA2 gene and lactamase production was observed for 1 Prevotella buccalis strain. The gene was in 1 P micra strain but was not expressed. Three strains were positive for lactamase production, but the cfxAlcfxA2 gene was not detected through polymerase chain reaction. There is a low prevalence of the cfxAl cfxA2 gene and its expression in Porphyromonas spp., Prevotella spp., and P. micra strains isolated from acute endodontic infections. Genetic and phenotypic screening must be performed simultaneously to best describe additional mechanisms involved in lactamic resistance for strict anaerobes403339344FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DO RIO GRANDE DO SUL - FAPERGSFederal University of Rio Grande do Su

    Composicao fisica da carcaca de bezerros da raca Holandesa alimentados com dietas contendo diferentes niveis de concentrado.

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    O objetivo deste estudo foi avaliar o efeito dos diferentes niveis de concentrado nas dietas sobre a composicao fisica da carcaca. Trinta e dois bezerros da raca Holandesa, PC, variedade preto e branco, divididos em dois grupos de abate (grupo 1: 16 animais abatidos com 190 + ou - 10kg PV e grupo 2: 16 animais abatidos com 300 + ou - 10kg, com, em media, 75 dias de idade e 78 kg PV inicial, foram distribuidos em delineamento inteiramente casualizado, com quatro tratamentos e quatro repeticoes para ambos os grupos. Os animais foram alimentados a vontade com dietas contendo 45,0; 60,0; 75,0 e 90,0% de concentrado na base da racao (%MS), usando-se feno de capim coast-cross (Cynodon dactylon), fuba de milho e farelo de soja, os quais constituiram dietas com aproximadamente 16% PB. A cada periodo de 28 dias, os animais foram pesados e abatidos quando se aproximavam do peso de abate preestabelecido para os grupos 1 e 2. A proporcao de ossos na carcaca dos animais do grupo 1 nao foi influenciada, porem a de musculos diminuiu e a de gordura e as relacoes tecido adiposo: osseo e tecido adiposo: muscular aumentaram linearmente, em funcao dos niveis de concentrado nas racoes. O aumento do nivel de concentrado nas racoes influenciou somente a relacao tecido muscular: osseo na carcaca dos animais do grupo 2

    Mutations in TSC1, TSC2, and MTOR are associated with response to rapalogs in patients with metastatic renal cell carcinoma

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    Purpose: We examined the hypothesis that mutations in mTOR pathway genes are associated with response to rapalogs in metastatic renal cell carcinoma (mRCC). Experimental Design: We studied a cohort of mRCC patients who were treated with mTOR inhibitors with distinct clinical outcomes. Tumor DNA from 79 subjects was successfully analyzed for mutations using targeted next-generation sequencing of 560 cancer genes. Responders were defined as those with partial response (PR) by RECIST v1.0 or stable disease with any tumor shrinkage for 6 months or longer. Nonresponders were defined as those with disease progression during the first 3 months of therapy. Fisher exact test assessed the association between mutation status in mTOR pathway genes and treatment response. Results: Mutations in MTOR, TSC1, or TSC2 were more common in responders, 12 (28%) of 43, than nonresponders, 4 (11%) of 36 (P = 0.06). Mutations in TSC1 or TSC2 alone were also more common in responders, 9 (21%), than nonresponders, 2(6%), (P = 0.05). Furthermore, 5 (42%) of 12 subjects with PR had mutations in MTOR, TSC1, or TSC2 compared with 4 (11%) of 36 nonresponders (P = 0.03). Eight additional non-mTOR pathway genes were found to be mutated in at least 4 of 79 tumors (5%); none were associated positively with response. Conclusions: In this cohort of mRCC patients, mutations in MTOR, TSC1, or TSC2 were more common in patients who experienced clinical benefit from rapalogs than in those who progressed. However, a substantial fraction of responders (24 of 43, 56%) had no mTOR pathway mutation identified

    Quantitative Observation of Magnetic Flux Distribution in New Magnetic Films for Future High Density Recording Media

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    International audienceOff-axis electron holography was used to observe and quantify the magnetic microstructure of a perpendicular magnetic anisotropic (PMA) recording media. Thin foils of PMA materials exhibit an interesting up and down domain configuration. These domains are found to be very stable and were observed at the same time with their stray field, closing magnetic flux in the vacuum. The magnetic moment can thus be determined locally in a volume as small as few tens of cubic nanometers

    A phase II trial of docetaxel and erlotinib as first-line therapy for elderly patients with androgen-independent prostate cancer

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    Background: Docetaxel is the standard first-line agent for the treatment of androgen-independent prostate cancer (AIPC). The combination of docetaxel with molecularly targeted therapies may offer the potential to increase the efficacy and decrease the toxicity of cytotoxic chemotherapy for prostate cancer. Previous studies demonstrate activation of the human epidermal growth factor receptor (EGFR) in prostate cancer. Erlotinib is a specific inhibitor of the tyrosine-kinase activity of EGFR. The goal of this study is to determine the anti-cancer activity docetaxel combined with erlotinib for the treatment of elderly subjects with AIPC. Methods: This is a multi-institutional Phase II study in patients with histologically confirmed adenocarcinoma of the prostate and age [greater than or equal to] 65 years. Patients were requred to have progressive disease despite androgen-deprivation therapy as determined by: (1) measurable lesions on cross-sectional imaging; (2) metastatic disease by radionucleotide bone imaging; or (3) elevated prostate specific antigen (PSA). Treatment cycles consisted of docetaxel 60 mg/m2 IV on day 1 and erlotinib 150 mg PO days 1-21. Patients with responding or stable disease after 9 cycles were eligible to continue on erlotinib alone as maintenance therapy. Results: Characteristics of 22 patients enrolled included: median age 73.5 years (range, 65-80); median Karnofsky Performance Status 90 (range 70-100); median hemoglobin 12.1 g/dl (range, 10.0-14.3); median PSA 218.3 ng/ml (range, 9-5754). A median of 6 treatment cycles were delivered per patient (range 1-17). No objective responses were observed in 8 patients with measurable lesions (0%, 95% CI 0-31%). Bone scan improvement and PSA decline was seen in 1 patient (5%, 95% CI 0.1-25%). Five of 22 patients experienced [greater than or equal to] 50% decline in PSA (23%, 95% CI 8-45%). Hematologic toxicity included grade 3 neutropenia in 9 patients and neutropenic fever in 2 patients. Common non-hematologic toxicities ([greater than or equal to] grade 3) included fatigue, anorexia, and diarrhea. Conclusion: Docetaxel/erlotinib can be delivered safely in elderly patients with AIPC. Anti-cancer disease activity appears generally comparable to docetaxel when used as monotherapy. Hematologic and nonhematologic toxicity may be increased over docetaxel monotherapy. Prospective randomized studies would be required to determine if the toxicity of docetaxel and erlotinib justifies its use in this setting.This study was supported by NIH Prostate SPORE P50 CA92131 to DBA. Phase One Foundation to MEG and DBA

    Composição corporal e exigĂȘncias lĂ­quidas de energia e proteĂ­na de bezerros da raça Holandesa alimentados com dietas contendo diferentes nĂ­veis de volumoso.

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    O objetivo deste trabalho foi avaliar os efeitos de diferentes nĂ­veis de volumoso nas dietas, sobre a composição corporal, as exigĂȘncias de energia lĂ­quida para mantença e ganho de peso e os requerimentos lĂ­quidos de proteĂ­na para ganho de peso. Cinquenta e dois bezerros da raça Holandesa, puros por cruzamento, nĂŁo-castrados, com idade mĂ©dia de 60 dias e peso vivo (PV) inicial de 78 kg foram usados. Oito animais foram abatidos ao inĂ­cio do experimento, como referĂȘncia. Outros oito animais foram alimentados com dietas na proporção de 90% de volumoso e 10% de concentrado para atender Ă s exigĂȘncias ligeiramente acima da mantença (grupo de mantença). Os 36 animais restantes foram distribuĂ­dos nos tratamentos, em delineamento inteiramente casualizado, em quatro grupos de nove animais, de acordo com o nĂ­vel de volumoso nas dietas: 10, 25, 40 e 55%, na base da MS, usando-se feno de capim coast-cross (Cynodon dactylon), fubĂĄ de milho e farelo de soja, os quais constituĂ­ram dietas com aproximadamente 16% de PB.. Cinco animais de cada tratamento foram abatidos, quando atingiram 190 ± 10 kg PV e quatro, quando atingiram 300 ± 10 kg PV. A exigĂȘncia de energia lĂ­quida (EL) para mantença foi estimada da equação de regressĂŁo do logaritmo da producĂŁo de calor e em relação ao consumo de energia metabolizĂĄvel (CEM), assumindo CEM igual a zero. EquaçÔes de regressĂŁo foram ajustadas, para cada nĂ­vel de volumoso e em conjunto, do logaritmo das quantidades corporais de gordura, proteĂ­na e energia, em função do logaritmo do peso corporal vazio (PCVZ). A exigĂȘncia de energia lĂ­quida para mantença foi, em mĂ©dia, de 110,46 kcal/kg0,75. A quantidade de gordura e o conteĂșdo de energia no ganho de peso aumentaram, Ă  medida que se elevou o PV do animal, para todos os nĂ­veis de volumoso e em conjunto. As exigĂȘncias lĂ­quidas de energia e proteĂ­na para ganho de 1 kg de PCVZ, para um animal de 300 kg de peso vivo, foram 2,83 Mcal/dia e 183,20 g/dia, respectivamente. As exigĂȘncias lĂ­quidas de energia e proteĂ­na para ganho de bezerros da raça Holandesa, em mĂ©dia, aumentaram com o aumento do peso corporal vazio

    Composicao corporal e exigencias liquidas de energia e proteina de bezerros alimentados com dietas contendo diferentes niveis de volumoso.

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    O objetivo deste trabalho foi avaliar os efeitos dos cincos niveis de volumoso sobre a composicao corporal, as exigencias de energia liquida para mantenca e ganho de peso e os requerimentos liquidos de proteina para ganho de peso. Foram usados quarenta e oito bezerros mesticos (Holandes x Zebu), machos, nao-castrados, com idade aproximada de 60 dias e peso vivo medio inicial de 60 kg. Oito animais foram abatidos ao inicio do experimento, para servirem de referencia; 32 foram alimentados a vontade com concentrado e feno de capim coast-cross (Cynodon dactylon) e distribuidos em quatro grupos de oito animais, de acordo com cada sistema de alimentacao, tratamentos (T), com os seguintes niveis de volumoso nas dietas na base da materia seca: T1 = 10, T2 =25; T3 = 40 e T4 = 55%; e oito animais receberam 90% de volumoso e 10% de concentrado (T5), para atender as exigencias ligeiramente acima da mantenca. Quatro animais de cada tratamento foram abatidos quando atingiram 180 + - 10 kg PV (grupo 2); os outros quatro, ao atingirem o peso 300 + - 10 kgPV (grupo 1); e os do grupo de mantenca, com pesos variados e idade media de abate dos grupos 1 e 2. As exigencias de energia liquida para mantenca foram determinadas em funcao do consumo de energia metabolizavel (EM), para o nivel zero de ingestao de EM. Equacoes de regressao do logaritimo dos conteudos corporais de gordura, energia e proteina foram ajustadas em funcao do logaritimo do peso corpo vazio (PCVZ). Valores de exigencias de energia liquida para mantenca de 71,76 e 8465 Kcal/kg0,75, respectivamente, forma obtidos para animais com 180 e 300 Kg. A quantidade de gordura e o conteudo de energia no peso ganho aumentaram, a medida que se elevou o peso vivo do animal, para todos os niveis de volumoso. A exigencia de energia liquida para mantenca, estimada para os dois grupos em conjunto, foi de 81,3 Kcal/Kg0,75PCVZ. Os valores obtidos foram, em media, 3,46 Mcal e 196g de energia liquida e proteina no kg de ganho de PCVZ, para animais de 300 kg de peso vivo
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