651 research outputs found

    Gas mass-flow meters: Principles and applications

    Get PDF
    Gas mass-flow meters (GMFM) for original equipment manufacturers (OEM) applications are presently found in a relatively easy and cheap way. GMFM may be applied in a number of different situations but technical formation concerning its principles of measurement and applications are still misleading. In this paper, the principles of GMFM measurement are discussed and the operating parameters are clarified. A concept of gas mass-flow response factor is introduced and further used in a model for gas mass-flow measurement that is suitable to any gas mixture of known composition. In addition, a model for the application of GMFM to dynamic volumetric methods of dilution is presented and generalized

    Efficient Haplotype Inference with Pseudo-Boolean Optimization

    No full text
    Abstract. Haplotype inference from genotype data is a key computational problem in bioinformatics, since retrieving directly haplotype information from DNA samples is not feasible using existing technology. One of the methods for solving this problem uses the pure parsimony criterion, an approach known as Haplotype Inference by Pure Parsimony (HIPP). Initial work in this area was based on a number of different Integer Linear Programming (ILP) models and branch and bound algorithms. Recent work has shown that the utilization of a Boolean Satisfiability (SAT) formulation and state of the art SAT solvers represents the most efficient approach for solving the HIPP problem. Motivated by the promising results obtained using SAT techniques, this paper investigates the utilization of modern Pseudo-Boolean Optimization (PBO) algorithms for solving the HIPP problem. The paper starts by applying PBO to existing ILP models. The results are promising, and motivate the development of a new PBO model (RPoly) for the HIPP problem, which has a compact representation and eliminates key symmetries. Experimental results indicate that RPoly outperforms the SAT-based approach on most problem instances, being, in general, significantly more efficient

    The influence of menopausal status on bone turnover and disease control in breast cancer patients with metastatic bone disease treated with chemotherapy plus zoledronic acid : an exploratory retrospective cohort study

    Get PDF
    RESUMO: Introdução: Uma meta-análise recente demonstrou que uso adjuvante de ácido zoledrónico (AZ) em mulheres pós-menopáusicas com cancro da mama precoce (CM) conduz a redução do risco de morte por CM em 17%. Investigámos o efeito do estado hormonal (pré [PrM] vs pós-menopausa tardia [PoM]) na remodelação óssea e controlo de doença em mulheres com CM e metástases ósseas (MO) tratadas com AZ e quimioterapia (QT). Métodos: Neste estudo de coorte retrospetivo, colhemos variáveis clinico-patológicas e quantificámos o telopéptido N-terminal (NTX) urinário e marcadores tumorais (MT) séricos em mulheres com CM e MO tratadas com QT e AZ. As doentes foram divididas em PrM (60 anos). Endpoints do estudo: variação do NTX, CA15.3 e CEA nos meses 3, 6 e 9, tempo até falência de QT de primeira-linha e sobrevivência. Quando apropriado foram usados os testes de Wilcoxon rank-sum, modelo de efeitos lineares mistos, teste log-rank e modelo de Cox. Resultados: Quarenta doentes foram elegíveis para análise (8 PrM e 32 PoM). Depois da introdução de AZ e QT, os níveis de NTX e MT caíram no coorte global. O perfil de resposta não diferiu entre grupos no mês 3 ou em tempos posteriores (valor-p para interação tempo-estado hormonal no mês 3=0.957). Ademais, o perfil de resposta dos MT também não diferiu entre grupos. O tempo mediano até falência de primeira-linha de QT em PrM e PoM foi de 15.2 e 17.4 meses, respetivamente. Não foi identificada diferença significativa entre grupos, quer em análise univariada quer após controlo para envolvimento visceral (p=0.399 e 0.469, respetivamente). Igualmente, não houve diferenças em termos de sobrevivência. Conclusões: Neste coorte, não foram identificadas diferenças no controlo de NTX ou MT em função do estado menopausico. Igualmente, não foi identificada diferença no tempo até falência de primeira-linha de CT ou sobrevivência.----------- ABSTRACT: Background: A recent meta-analysis showed that the adjuvant use of zoledronic acid (ZA) in postmenopausal women with early breast cancer (BC) leads to a reduction in the risk of breast cancer death by 17%. We investigated the effect of the hormonal status (pre [PrM] vs late post menopause [PoM]) on bone turnover and disease control among women with BC and boné metastases (BM) treated with ZA and chemotherapy (CT). Methods: In this retrospective cohort study, we collected clinicopathologic variables, urinary Nterminal telopeptide (NTX) and serum tumor marker levels from women with BC and BM treated with CT and ZA. Patients were divided in PrM (60 years). Study endpoints were NTX, CA15.3 and CEA variation at 3, 6 and 9 months, and time to first-line CT failure and survival. We performed multilevel mixed-effects linear regression models to assess the variation of repeated measures and cox regression models for time to event outcomes. Results: Forty patients were eligible for analysis (8 PrM and 32 PoM). After introduction of ZA and CT, NTX and tumor markers declined in the overall cohort. Response profile was similar between menopausal groups at month 3 and at later time points (p-value for time-hormonal status interaction at month 3=0.957). Furthermore, tumor markers response profile was also equal between groups. Median time to first-line CT failure in PrM and PoM women was 15.2 and 17.4 months, respectively. No significant difference between groups was found, either using a univariate analysis or after controlling for visceral disease involvement (p=0.399 and 0.469, respectively). Likewise, no differences in survival were found. Conclusions: In this cohort, no differences were found in terms of NTX or tumor markers control according to menopausal status. Similarly, no difference in time to first-line CT failure or survival was found

    Using MERRA Gridded Innovations for Quantifying Uncertainties in Analysis Fields and Diagnosing Observing System Inhomogeneities

    Get PDF
    MERRA is a NASA reanalysis for the satellite era using a major new version of the Goddard Earth Observing System Data Assimilation System Version 5 (GEOS-5). The project focuses on historical analyses of the hydrological cycle on a broad range of weather and climate time scales and places the NASA EOS suite of observations in a climate context. The characterization of uncertainty in reanalysis fields is a commonly requested feature by users of such data. While intercomparison with reference data sets is common practice for ascertaining the realism of the datasets, such studies typically are restricted to long term climatological statistics and seldom provide state dependent measures of the uncertainties involved. In principle, variational data assimilation algorithms have the ability of producing error estimates for the analysis variables (typically surface pressure, winds, temperature, moisture and ozone) consistent with the assumed background and observation error statistics. However, these "perceived error estimates" are expensive to obtain and are limited by the somewhat simplistic errors assumed in the algorithm. The observation minus forecast residuals (innovations) by-product of any assimilation system constitutes a powerful tool for estimating the systematic and random errors in the analysis fields. Unfortunately, such data is usually not readily available with reanalysis products, often requiring the tedious decoding of large datasets and not so-user friendly file formats. With MERRA we have introduced a gridded version of the observations/innovations used in the assimilation process, using the same grid and data formats as the regular datasets. Such dataset empowers the user with the ability of conveniently performing observing system related analysis and error estimates. The scope of this dataset will be briefly described. We will present a systematic analysis of MERRA innovation time series for the conventional observing system, including maximum-likelihood estimates of background and observation errors, as well as global bias estimates. Starting with the joint PDF of innovations and analysis increments at observation locations we propose a technique for diagnosing bias among the observing systems, and document how these contextual biases have evolved during the satellite era covered by MERRA

    Evolution of factors affecting mechanical olive harvesting

    Get PDF
    Harvest efficiency is defined as the percentage of fruits harvested by total production. The percentage of fruits harvested is less than 100% when working with trunk shakers to detach olives. It is important to increase the percentage of fruits harvested in order to increase farmer’s income. This objective can be achieved knowing the evolution of the main factors affecting fruit detachment. Fruit removal force (FRF), fruit weight (P) and the ratio between them are important for harvest efficiency. Field trials took place for two years (2013-2014) in Vilariça Valley, northeast Portugal in an olive orchard with ‘Cobrançosa Transmontana’ cultivar. It was adopted a mechanical harvesting system based on a trunk shaker to detach fruits, and an inverted umbrella to collect fruits. Elementary operation times were measured in seconds to evaluate work rates. FRF and P were measured in the ripening period, to evaluate their evolution. In this paper are presented the preliminary results of the ratio FRF (fruit removal force)/fruit weight evolution during the ripening period (P) and the results of the equipment work rate (trees h-1). The ratio FRF/P has predominantly descendant values in the weeks before harvest, from 140 to 80 as a result of a FRF downward variation from 4.9 to 2.94 N and an upward variation of P from 0.0294 to 0.0637 N. The FRF/P ratio stabilizes the decline in the last week of November just before harvesting, registering in some cases a slight increase in consequence of FRF increase higher than P increase (contrary to the tendency of previous weeks). Equipment work rate showed values between 40 and 57 trees h-1, confirming previous results.The authors want to thank to the Program PRODER Medida 4.1 Nº 44663 for the financial support, to the farmer of Quinta do Carrascal – Viaz and personnel involved in the field trials allowing to get data presented

    Evolution of factors affecting mechanical olive harvesting

    Get PDF
    Harvest efficiency is defined as the percentage of fruits harvested by total production. The percentage of fruits harvested is less than 100% when working with trunk shakers to detach olives. It is important to increase the percentage of fruits harvested in order to increase farmer’s income. This objective can be achieved knowing the evolution of the main factors affecting fruit detachment. Fruit removal force (FRF), fruit weight (P) and the ratio between them are important for harvest efficiency. Field trials took place for two years (2013-2014) in Vilariça Valley, northeast Portugal in an olive orchard with ‘Cobrançosa Transmontana’ cultivar. It was adopted a mechanical harvesting system based on a trunk shaker to detach fruits, and an inverted umbrella to collect fruits. Elementary operation times were measured in seconds to evaluate work rates. FRF and P were measured in the ripening period, to evaluate their evolution. In this paper are presented the preliminary results of the ratio FRF (fruit removal force)/fruit weight evolution during the ripening period (P) and the results of the equipment work rate (trees h-1). The ratio FRF/P has predominantly descendant values in the weeks before harvest, from 140 to 80 as a result of a FRF downward variation from 4.9 to 2.94 N and an upward variation of P from 0.0294 to 0.0637 N. The FRF/P ratio stabilizes the decline in the last week of November just before harvesting, registering in some cases a slight increase in consequence of FRF increase higher than P increase (contrary to the tendency of previous weeks). Equipment work rate showed values between 40 and 57 trees h-1, confirming previous results.The authors want to thank to the Program PRODER Medida 4.1 Nº 44663 for the financial support, to the farmer of Quinta do Carrascal – Viaz and personnel involved in the field trials allowing to get data presented

    Data used as an indicator of mechanical olive harvest season

    Get PDF
    When and how harvest olives are among the most important issues to improve quality and quantity to ensure the best net return to growers. Trunk shakers are commonly used in mechanical harvesting to detach olives. Field trials showed that with this equipment less than 100% of the production is detached, usually 70% to 90% (Michelakis, 2002).It is important to increase the percentage of fruits harvested, to reduce losses. To achieve this goal factors affecting mechanical olive harvesting must be known, to be used in the definition of harvest season. Some of these factors are the result of the orchard management, like tree shape, canopy density, pruning methods. Others depend on the cultivar, such as fruit removal force (FRF), fruit weight (P) and the ratio between them. FRF and P are considered decisive in the detachment process. Results of field trials carried out in the Northeast of Portugal with “Cobrançosa Transmontana” cultivar show the FRF, P and their ratio evolution in the ripening period. They have potential to become indicators of the mechanical olive harvest season

    Olives mechanical harvesting trunk shaker based - costs update

    Get PDF
    Resultados de capacidade de trabalho (árvores/hora) e custos de utilização (por kg azeitona colhida) obtidos em trabalho de campo realizado em Portugal ao longo de mais de cinco anos em olivais com 150 árvores por hectare (em média) foram publicados por Almeida et al (2001) e Almeida et al (2007). Dois sistemas de colheita foram utilizados, ambos com o mesmo vibrador de tronco. No sistema I a azeitona destacada foi recolhida em lonas movimentadas manualmente. No sistema II a azeitona destacada foi recolhida num apara-frutos mecânico. A capacidade de trabalho média do sistema I é de 57 árvores por hora e do sistema II é de 40 árvores por hora. Os resultados mostram que o tempo gasto no deslocamento entre árvores é importante para o valor da capacidade de trabalho. Com o sistema baseado em recolha manual foram obtidos melhores resultados de capacidade de trabalho, mas os custos de utilização do sistema baseado no apara-frutos mecânico foram mais favoráveis. Dependendo do número de árvores vibradas por hora, para o sistema I os custos médios atuais são de 0,36 € a 0,12 € por kg de azeitona colhida e para o sistema II os custos médios atuais são de 0,36 € a 0,11 € por kg de azeitona colhida. Mais de uma década após a publicação dos primeiros resultados, os preços dos equipamentos, da mão-de-obra e de outros fatores, são substancialmente diferentes, assim como o valor da azeitona. Uma atualização de custos é apresentada e analisadas as consequências para os referidos sistemas de colheita mecânica. O acréscimo de custos neste período de tempo é de 49%.Results ofwork rates (trees/hour) and costs (per kg of olives harvested) from field trials performed in Portugal over more than tive years in olive orchards averaging 150 trees per hectare, was published by Almeida, A. et al (2001) and Almeida, A. et al (2007). Olives were harvested using two han/esting systems, both with the same trunk shaker, but in system l olives detached were collected by canvas manually moved and in system II olives detached were collected with an inverted umbrella. The average working rate of system l is 57 trees per hour. The average working rate of system l is 40 trees per hour. Results showed that the time spent in the displacement between trees is very important for the work rate value. Labour based manual collecting was found to reach the higher working rates, whereas in terms of costs the inverted umbrella scored best results. According on the number of trees harvested per year, the actual médium costs for system l are 0,36 to 0,12 per kg of olives harvested and the actual médium costs for system II are 0,36 to 0,11 per kg of olives harvested. More than one decade after the publication of first results, equipment and labour costs are substantial different as well as olive production value. Costs are updated and analyzed the consequences for referred olive mechanical harvesting systems. The costs increase in this period of time is 49%.info:eu-repo/semantics/publishedVersio
    corecore