919 research outputs found

    Development of semi-theoretical light radiation and photosynthetic growth model for the optimal exploitation of wastewaters by microalgae

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    In the last decade, interest toward the potential application of microalgae has grown considering their potential use in industrial sectors as human nutrition and health, animal feed and biopolymers. Their ability to use light or/and organic carbon as energy source, makes them able to grow in a wide range of conditions. Because of that, the possibility to use alternative nutrients and water sources for their cultivation has been investigated. The microalgal cultivation using wastewaters mixed with synthetic medium might be a good combination that could reduce costs of water, nutrients and wastewater treatment. Anyway, wastewaters are frequently dark colored and contain toxic compounds that could have a negative impact on microalgal light uptake and metabolism. In this study, an experimental first principles hybrid method for the estimation of microalgal growth in non-transparent media was developed as a guide in the choice of the best formulation of wastewater-based culture media for microalgae. To carry out several experimental runs in parallel with different conditions (dilution of the wastewater, different light sources, etc.) a cylindrical bubble column PhotoBioReactor (PBR) was adopted. Its simple geometry allows the analysis of inside light fluxes. A non-metabolizable and non-toxic dye, in condition of purely light-radiative growth limitation, was added to the medium mimicking the reduced transparency of wastewaters. As final step to test the model, culture mediums with wastewater addiction were used for microalgal cultivation, showing their nutritive effects on growth

    Spherical orbit closures in simple projective spaces and their normalizations

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    Let G be a simply connected semisimple algebraic group over an algebraically closed field k of characteristic 0 and let V be a rational simple G-module of finite dimension. If G/H \subset P(V) is a spherical orbit and if X is its closure, then we describe the orbits of X and those of its normalization. If moreover the wonderful completion of G/H is strict, then we give necessary and sufficient combinatorial conditions so that the normalization morphism is a homeomorphism. Such conditions are trivially fulfilled if G is simply laced or if H is a symmetric subgroup.Comment: 24 pages, LaTeX. v4: Final version, to appear in Transformation Groups. Simplified some proofs and corrected minor mistakes, added references. v3: major changes due to a mistake in previous version

    Nutrient dietary patterns and the risk of laryngeal cancer : an Italian case-control study

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    Introduction. Several studies have indicated a role of diet in the etiology of laryngeal cancer. Since foods and nutrients tend to be closely related and act synergistically, the pecific effect of each dietary component of interest may be difficult to identify and can be partly confounded by other dietary components. Dietary patterns have thus been proposed as a practical tool to describe the association between diet and cancer, given their ability to capture the variations in overall food intake (Newby, Tucker 2004). A few studies have investigated the role of diet on laryngeal cancer through factor analysis. Aims We applied exploratory principal component factor analysis (PCFA) to identify a posteriori dietary patterns for a multicentric case-control study conducted in Italy on cancer of the larynx. This a posteriori technique allows to integrate several dietary exposures (i.e. foods, food groups, nutrients) into a smaller number of dietary patterns, that are independent from one another and can be evaluated as risk factors in subsequent analysis for the assessment of cancer risk. Methods A case-control study of cancer of the larynx was conducted from 1992 and 2000 in the provinces of Milan and Pordenone, in the Northern Italy. Cases were 460 subjects (415 men, 45 women) admitted to major teaching and general hospitals in the study areas with incident, histologically confirmed squamous cell cancer of the larynx, diagnosed no longer than 1 year before the interview. Controls were 1088 subjects (863 men, 225 women) admitted to the same hospitals for a wide spectrum of acute, non-neoplastic conditions, unrelated to smoking or alcohol drinking, or long term modifications of diet. The subjects\u2019 diet was assessed using a valid and reproducible food frequency questionnaire (FFQ) including 78 foods and beverages, as well as a range of the most common Italian recipes. Subjects were asked to indicate the average weekly consumption for each dietary item; intakes lower than once a month were coded as 0.5 per week. To estimate the intake of various nutrients, an Italian food composition database was used. We performed an exploratory PCFA on a selected set of 28 major macro- and micro-nutrients. We preliminarily evaluated the correlation matrix to determine if it was factourable, trough visual inspection and statistical procedure (Bartlett\u2019s test of sphericity). Moreover, we evaluated the Kaiser-Meyer-Olkin measure and individual measures of sampling adequacy (Kaiser, 1974). We chose the number of factors to retain based on the following criteria: factor eigenvalue greater than 1, scree plot examination and factor interpretability. We applied a varimax rotation to the factor loadings matrix to achieve a simpler and more interpretable solution. We used nutrients with rotated factor loading greater or equal to 0.63 on a given factor to name the pattern. Factor scores were defined for each subject and for each factor following the weighted least square method. They indicate the degree to which each subject\u2019s diet conforms to one of the identified patterns. To examine the robustness of the identified dietary patterns, we performed a principal axis factor analysis on the standardized nutrients and a maximum likelihood factor analysis after logarithmic transformation of the original nutrients. We calculated factor scores referring to the multiple regression method and standardizing the results. The correlations between scores referring to the same factor calculated with different methods were equal to 1 for all the comparisons. We also performed factor analysis separately within male and female subsamples and within different centers. All these checks yielded dietary patterns consistent with PCFA the ones obtained on the overall sample. To assess the reliability and refine the identified factors, we evaluated the internal consistency of those nutrients with a loading greater than 0.40 using standardized Cronbach\u2019s coefficient alpha. We calculated coefficient alphas for each factor and coefficient alphas when item deleted (Cronbach, 1951). To confirm the internal reproducibility of the identified patterns, individuals were randomly placed into one of two equally sized groups, and PCFA was performed separately in both subsamples. For each factor, we grouped participants into three categories according to quintiles of factor scores among the control population, and estimated the odds ratio and corresponding 95% confidence intervals using unconditional multiple logistic regression models, including all the factors simultaneously. The model was adjusted for sex, age, study center, education, body mass index, physical activity, tobacco smoking, and alcohol drinking. Results Five factors were retained according to the defined criteria. These factors explained 79% of the total variance of the original nutrients. The first pattern, named Animal products, had the greatest loadings on calcium, phosphorus, riboflavin, animal protein, saturated fatty acids, zinc, and cholesterol. The second pattern, named Starch-rich, had the greatest loadings on starch, vegetable protein, and sodium. The third pattern, named Vitamins and fiber, had the greatest loadings on vitamin C, total fiber, beta-carotene equivalents, and total folate. The fourth pattern, named Seed oils, had the greatest loadings on linoleic acid, vitamin E, and linolenic acid. The fifth pattern, named Fish-rich, had the greatest loadings on other polyunsaturated fatty acids, and vitamin D. A direct association was observed between the Animal products pattern and laryngeal cancer (OR=1.94, 95% CI: 1.39-2.70). A borderline direct association was observed between the Starch-rich pattern and laryngeal cancer (OR=1.30, 95% CI: 0.93-1.81). An inverse relationship was observed between the Vitamins and fiber pattern and laryngeal cancer (OR=0.56, 95% CI: 0.41-0.76). No relationship was evident between the Seed oils pattern and laryngeal cancer (OR=0.98, 95% CI: 0.70-1.37). A direct association was found between the Fish-rich pattern and the laryngeal cancer (OR=2.09, 95% CI: 1.51-2.90). Conclusions The role of dietary habits on the risk of laryngeal cancer was evaluated through exploratory PCFA on 28 major nutrients of interest. We identified 5 major dietary patterns, explaining about 80% of the total variance of the original nutrients. Our results indicated that the Animal products and Fish-rich patterns are potentially unfavourable indicators of risk for laryngeal cancer, while the Vitamins and fiber pattern is inversely related to laryngeal cancer

    Buildings energy performance and real estate market value: An application of the spatial auto regressive (SAR) model

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    The paper explores the role of the buildings energy performance in the definition of the real estate market value, taking in consideration the presence of spatial auto-correlation. At this regard, it is necessary to put in evidence that a great heterogeneity exists on the Italian territory with reference to buildings ener-gy performance; for this reason, being able to identify a class of most performing estimation models, suitable to separate the spatial effects from the influence of the building components - including the energy rating - on the value, seems to be an interesting goal. In particular, this work illustrates an experiment based on the Spatial Auto Regressive (SAR) model implemented on a sample of residential units located in the city of Turin and represents a first step of a more wide research program

    In vitro ion chelating, antioxidative mechanism of extracts from fruits and barks of tetrapleura tetraptera and their protective effects against fenton mediated toxicity of metal ions on liver homogenates

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    The aim of the present study was to investigate the antioxidant activity and protective potential of T. tetraptera extracts against ion toxicity. The antioxidant activity of the extracts was investigated spectrophotometrically against several radicals (1,1-diphenyl-2-picrylhydrazyl (DPPH•), 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS•), hydroxyl radical (HO•), and nitric oxide (NO•)), followed by the ferric reducing power, total phenols, flavonoid, and flavonol contents. The effects of the extracts on catalase (CAT), superoxide dismutase (SOD), and peroxidase activities were also determined using the standard methods as well as the polyphenol profile using HPLC. The results showed that the hydroethanolic extract of T. tetraptera (CFH) has the lowest ICvalue with the DPPH, ABTS, OH, and NO radicals. The same extract also exhibited the significantly higher level of total phenols (37.24 ± 2.00 CAE/g dried extract); flavonoids (11.36 ± 1.88 QE/g dried extract); and flavonols contents (3.95 ± 0.39 QE/g dried extract). The HPLC profile of T. tetraptera revealed that eugenol (958.81 ± 00 mg/g DW), quercetin (353.78 ± 00 mg/g DW), and rutin (210.54 ± 00 mg/g DW) were higher in the fruit than the bark extracts. In conclusion, extracts from T. tetraptera may act as a protector against oxidative mediated ion toxicity. © 2015 Bruno Moukette Moukette et al

    Analisis Pengaruh Rx Level Terhadap Kecepatan Download Data Pada Teknologi GPRS Di PT XL Axiata Tbk. Purwokerto

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    Data transfer speed on GPRS\u27s technology isaffected by the present of some obstacles between sender\u27s side and recipient\u27s side. Those obstacles cause propagation loss that affect the reduction of power level value (rx level). The reduction will affect the data speed. The lower rx level\u27s value means the lower dataspeed. This researchwas done by doing drive test on BTS North Purwokerto and BTS Tambaksogra to measure the amount of power measured (Pr) andthe download data speed on GPRS\u27s network. The measuredpower level (Pr) was normalized to get rx level value. Regression analysis was done to get the relation between the download speed and the rx level value. Theanalysis has resulted in a model: download speed = 4.1 (rx level) 0.459 , with R^2 = 0.380. Correlation analysis shows high correlationbetween rx level and download speed (r = 0.608)

    Normality and smoothness of simple linear group compactifications

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    If G is a complex semisimple algebraic group, we characterize the normality and the smoothness of its simple linear compactifications, namely those equivariant GxG-compactifications which possess a unique closed orbit and which arise in a projective space of the shape P(End(V)), where V is finite dimensional rational G-module. Both the characterizations are purely combinatorial and are expressed in terms of the highest weights of V. In particular, we show that Sp(2r) (with r > 0) is the unique non-adjoint simple group which admits a simple smooth compactification.Comment: v2: minor changes, final version. To appear in Math.

    Understanding the Private Worlds of Physicians, Nurses, and Parents: A Study of Life-Sustaining Treatment Decisions in Italian Paediatric Critical Care

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    This study's aim was to describe: (a) How life-sustaining treatment (LST) decisions are made for critically ill children in Italy; and (b) How these decisional processes are experienced by physicians, nurses and parents. Focus groups with 16 physicians and 26 nurses, and individual interviews with 9 parents were conducted. Findings uncovered the 'private worlds' of paediatric intensive care unit (PICU) physicians, nurses and parents; they all suffer tremendously and privately. Physicians struggle with the weight of responsibility and solitude in making LST decisions. Nurses struggle with feelings of exclusion from decisions regarding patients and families that they care for. Physicians and nurses are distressed by legal barriers to LST withdrawal. Parents struggle with their dependence on physicians and nurses to provide care for their child and strive to understand what is happening to their child. Features of helpful and unhelpful communication with parents are highlighted, which should be considered in educational and practice changes

    Risk factors for breast cancer in a cohort of mammographic screening program : a nested case-control study within the FRiCaM study

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    Breast cancer is the most common cancer diagnosis and the leading cause of cancer death among women in the world, and differences across populations indicate a role of hormonal, reproductive and lifestyle factors. This study is based on a cohort of 78,050 women invited to undergo a mammogram by Local Health Authority of Milan, between 2003 and 2007. We carried out a nested case\u2013control study including all the 3303 incident breast cancer cases diagnosed up to 2015, and 9909 controls matched by age and year of enrollment. Odds ratios (ORs) and corresponding 95% confidence intervals (CIs) were estimated using logistic regression models. The ORs were 0.88 (95% CI: 0.78\u20130.98) for an age at menarche 6514 years and 1.39 (95% CI: 1.07\u20131.81) for an age of 30 years or older at first pregnancy. Body mass index (BMI) was positively associated with breast cancer risk in women older than 50 years (OR = 1.89, 95% CI: 1.54\u20132.31, for BMI 6530 vs. 75% vs. adipose tissue). The ORs were 1.67 (95% CI: 1.47\u20131.89) and 2.04 (95% CI: 1.38\u20133.00) for one first\u2010degree relative and two or more relatives affected by breast cancer, respectively. Our study confirms the role of major recognized risk factors for breast cancer in our population and provides the basis for a stratification of the participants in the mammographic screening according to different levels of ris
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