842 resultados para exploratory
Resumo:
A rapid method for classification of mineral waters is proposed. The discrimination power was evaluated by a novel combination of chemometric data analysis and qualitative multi-elemental fingerprints of mineral water samples acquired from different regions of the Brazilian territory. The classification of mineral waters was assessed using only the wavelength emission intensities obtained by inductively coupled plasma optical emission spectrometry (ICP OES), monitoring different lines of Al, B, Ba, Ca, Cl, Cu, Co, Cr, Fe, K, Mg, Mn, Na, Ni, P, Pb, S, Sb, Si, Sr, Ti, V, and Zn, and Be, Dy, Gd, In, La, Sc and Y as internal standards. Data acquisition was done under robust (RC) and non-robust (NRC) conditions. Also, the combination of signal intensities of two or more emission lines for each element were evaluated instead of the individual lines. The performance of two classification-k-nearest neighbor (kNN) and soft independent modeling of class analogy (SIMCA)-and preprocessing algorithms, autoscaling and Pareto scaling, were evaluated for the ability to differentiate between the various samples in each approach tested (combination of robust or non-robust conditions with use of individual lines or sum of the intensities of emission lines). It was shown that qualitative ICP OES fingerprinting in combination with multivariate analysis is a promising analytical tool that has potential to become a recognized procedure for rapid authenticity and adulteration testing of mineral water samples or other material whose physicochemical properties (or origin) are directly related to mineral content.
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General objective: to analyse the exercise of essential competencies for midwifery care by nurses and/or midwives in the public health system of Sao Paulo (eastern zone), Brazil. Specific objectives: to develop a profile of the public health institutions and of the nurses and/or midwives who care for women before, during and following child birth; to identify the activities performed in providing such care, as well as their frequency; and to specify the possible obstacles or difficulties encountered by them when exercising their competencies. Design: a descriptive and exploratory research design , using a quantitative approach. Setting: the study was conducted in all public health services of Sao Paulo (eastern zone), Brazil, namely 59 basic health-care units and six hospitals, during the period of October 2006-December 2007. Participants: the study population consisted of 272 nurses and/or midwives who provide care for pregnant women and newborns at the primary health-care units and maternity hospitals of the public health system. Participants comprised 100% of hospital nurse coordinators (n = 6), 61% of hospital maternity nursing and/or midwifery staff (n = 62) and 64% (n = 204) of nursing and/or midwifery staff working at primary health-care units. Methods and findings: the data collection was based on a single form given to the coordinators and two questionnaires, one handed out to antenatal and postnatal nursing and/or midwifery staff and another handed out to labour and birth nursing and/or midwifery staff. The results showed that nurses and/or midwives providing care for women during pregnancy, labour, birth and the postnatal period did not put the essential competencies for midwifery care into practice, because they encountered institutional barriers and personal resistance, and lacked protocols based on best practice and on the exercise of essential competencies needed for effective midwifery care. Key conclusions: the model of care in the public health services of Sao Paulo (eastern zone) is based much more on hierarchical positions than on professional competencies or on there commendations of the scientific community. As a result, health authorities need to review their midwifery policies to improve maternal-infant care by nurses and/or midwives in order to ensure the implementation of best midwifery practice. Practical implications: the results of this study support actions to improve the quality of care delivered to women and their families, while integrating nursing and midwifery care in Sao Paulo, Brazil. (C) 2009 Elsevier Ltd. All rights reserved.
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Background: Depression is a common contributor to suffering and disability in people with chronic pain. However, the assessment of depression in this population has been hampered by the presence of a number of somatic symptoms that are shared between chronic pain, treatment side-effects and traditional concepts of depression. As a result, the use of depression measures that do not contain somatic items has been encouraged. Objective: This study examined the psychometric properties of the Depression sub-scale of the Depression Anxiety and Stress Scales (DASS) in a Brazilian chronic pain patient population. Method: Data on a number of measures were collected from 348 participants attending pain facilities. Results: Principal components and exploratory factor analyses indicated the presence of only one factor. Item analyses indicated adequate item-scale correlations. The Cronbach alpha was .96, which suggests an excellent internal consistency. Conclusion: The DASS-Depression scale has adequate psychometric properties and its further use with Brazilian chronic pain populations can now be supported. (c) 2008 Elsevier Inc. All rights reserved.
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Background: violence against women is a serious problem caused by the social construction of feminineness and masculineness that results in the domination of women by men. Public policies on gender have recently been developed in order to confront the problem. But what exactly are the problems faced by women? Purposes: to survey and analyse cases of violence against women reported to the police, as recorded at the Police Stations for Women`s Defence (PSWDs), and to reconstruct the procedures that women must go through in order to denounce their aggressors. Methodology: this quantitative, exploratory and descriptive study was undertaken during 2006-2007 in the city of Itapevi, Sao Paulo metropolitan region, Brazil. As there is no PSWD data were collected from police reports from PSWDs of neighbouring cities. Findings: malicious physical injury (49%) and threats (42%) were the most commonly reported types of violence. The victims were aged between 20 and 49 years (93%). Almost all of the aggressors (97%) were men and most had an intimate relationship with their victim. The use of alcoholic beverages was linked to approximately 25% of the cases. Conclusion: women who are victims of domestic violence in Itapevi report that going through PSWDs of neighbouring cities is a difficult, isolated, long and expensive process that often, provides no institutional protection. Implications for practice: there is an urgent requirement for judicial-assistance and support close to home in order to provide a quality service and follow-up for these women and their aggressors; to provide training for the professionals called to attend them at police stations; and for a caring attitude from health-care professionals.,0 2010 Elsevier Ltd. All rights reserved.
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This paper presents the lifecycle assessment (LCA) of fuel ethanol, as 100% of the vehicle fuel, from sugarcane in Brazil. The functional unit is 10,000 km run in an urban area by a car with a 1,600-cm(3) engine running on fuel hydrated ethanol, and the resulting reference flow is 1,000 kg of ethanol. The product system includes agricultural and industrial activities, distribution, cogeneration of electricity and steam, ethanol use during car driving, and industrial by-products recycling to irrigate sugarcane fields. The use of sugarcane by the ethanol agribusiness is one of the foremost financial resources for the economy of the Brazilian rural area, which occupies extensive areas and provides far-reaching potentials for renewable fuel production. But, there are environmental impacts during the fuel ethanol lifecycle, which this paper intents to analyze, including addressing the main activities responsible for such impacts and indicating some suggestions to minimize the impacts. This study is classified as an applied quantitative research, and the technical procedure to achieve the exploratory goal is based on bibliographic revision, documental research, primary data collection, and study cases at sugarcane farms and fuel ethanol industries in the northeast of SA o pound Paulo State, Brazil. The methodological structure for this LCA study is in agreement with the International Standardization Organization, and the method used is the Environmental Design of Industrial Products. The lifecycle impact assessment (LCIA) covers the following emission-related impact categories: global warming, ozone formation, acidification, nutrient enrichment, ecotoxicity, and human toxicity. The results of the fuel ethanol LCI demonstrate that even though alcohol is considered a renewable fuel because it comes from biomass (sugarcane), it uses a high quantity and diversity of nonrenewable resources over its lifecycle. The input of renewable resources is also high mainly because of the water consumption in the industrial phases, due to the sugarcane washing process. During the lifecycle of alcohol, there is a surplus of electric energy due to the cogeneration activity. Another focus point is the quantity of emissions to the atmosphere and the diversity of the substances emitted. Harvesting is the unit process that contributes most to global warming. For photochemical ozone formation, harvesting is also the activity with the strongest contributions due to the burning in harvesting and the emissions from using diesel fuel. The acidification impact potential is mostly due to the NOx emitted by the combustion of ethanol during use, on account of the sulfuric acid use in the industrial process and because of the NOx emitted by the burning in harvesting. The main consequence of the intensive use of fertilizers to the field is the high nutrient enrichment impact potential associated with this activity. The main contributions to the ecotoxicity impact potential come from chemical applications during crop growth. The activity that presents the highest impact potential for human toxicity (HT) via air and via soil is harvesting. Via water, HT potential is high in harvesting due to lubricant use on the machines. The normalization results indicate that nutrient enrichment, acidification, and human toxicity via air and via water are the most significant impact potentials for the lifecycle of fuel ethanol. The fuel ethanol lifecycle contributes negatively to all the impact potentials analyzed: global warming, ozone formation, acidification, nutrient enrichment, ecotoxicity, and human toxicity. Concerning energy consumption, it consumes less energy than its own production largely because of the electricity cogeneration system, but this process is highly dependent on water. The main causes for the biggest impact potential indicated by the normalization is the nutrient application, the burning in harvesting and the use of diesel fuel. The recommendations for the ethanol lifecycle are: harvesting the sugarcane without burning; more environmentally benign agricultural practices; renewable fuel rather than diesel; not washing sugarcane and implementing water recycling systems during the industrial processing; and improving the system of gases emissions control during the use of ethanol in cars, mainly for NOx. Other studies on the fuel ethanol from sugarcane may analyze in more details the social aspects, the biodiversity, and the land use impact.
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This study investigates the feasibility of an anaerobic bioreactor for treating low contents of organic matter to generate organic acids and hydrogen. The device employed for this purpose was a horizontal packed-bed bioreactor fed with glucose-based synthetic wastewater and operated with hydraulic retention times from 0.5 to 2 h. A microbial biofilm was developed without previous inoculation, using expanded clay beads (4.8-6.3 mm) as support material. Alkalinity was found to be the main parameter affecting the production of hydrogen and organic acids, and the system produced optimal output when operating without a buffer agent. The average hydrogen production was 2.48, 2.15 and 1.81 molH(2) mol(-1) of glucose for NaHCO3 influent concentrations of 0, 1000 and 2000 mg L-1, respectively. The operational regime of the bioreactor, the support material and the controlled alkalinity were effective in selecting and immobilizing microbial fermenting biofilms, which successfully produced hydrogen and organic acids throughout the operating period. Exploratory assays indicated the feasibility of organic acid extraction using an anionic polymeric resin. (C) 2007 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.
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The performance optimisation of overhead conductors depends on the systematic investigation of the fretting fatigue mechanisms in the conductor/clamping system. As a consequence, a fretting fatigue rig was designed and a limited range of fatigue tests was carried out at the middle high cycle fatigue regime in order to access an exploratory S-N curve for a Grosbeak conductor, which was mounted on a mono-articulated aluminium clamping system. Subsequent to these preliminary fatigue tests, the components of the conductor/clamping system, such as ACSR conductor, upper and lower clamps, bolt and nuts, were subjected to a failure analysis procedure in order to investigate the metallurgical free variables interfering on the fatigue test results, aiming at the optimisation of the testing reproducibility. The results indicated that the rupture of the planar fracture surfaces observed in the external At strands of the conductor tested under lower bending amplitude (0.9 mm) occurred by fatigue cracking (I mm deep), followed by shear overload. The V-type fracture surfaces observed in some At strands of the conductor tested under higher bending amplitude (1.3 mm) were also produced by fatigue cracking (approximately 400 mu m deep), followed by shear overload. Shear overload fracture (45 degrees fracture surface) was also observed on the remaining At wires of the conductor tested under higher bending amplitude (1.3 mm). Additionally, the upper and lower Al-cast clamps presented microstructure-sensitive cracking, which was folowed by particle detachment and formation of abrasive debris on the clamp/conductor tribo-interface, promoting even further the fretting mechanism. The detrimental formation of abrasive debris might be inhibited by the selection of a more suitable class of as-cast At alloy for the production of clamps. Finally, the bolt/nut system showed intense degradation of the carbon steel nut (fabricated in ferritic-pearlitic carbon steel, featuring machined threads with 190 HV), with intense plastic deformation and loss of material. Proper selection of both the bolt and nut materials and the finishing processing might prevent the loss in the clamping pressure during the fretting testing. It is important to control the specification of these components (clamps, bolt and nuts) prior to the start of large scale fretting fatigue testing of the overhead conductors in order to increase the reproducibility of this assessment. (c) 2008 Elsevier Ltd. All rights reserved.
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This in vitro study evaluated the antimicrobial activity of extracts obtained from Rheedia brasiliensis fruit (bacupari) and its bioactive compound against Streptococcus mutans. Hexane, ethyl-acetate and ethanolic extracts obtained (concentrations ranging from 6.25 to 800 mu g/ml) were tested against S. mutans UA159 through MIC/MBC assays. S. mutans 5-days-old biofilms were treated with the active extracts (100 x MIC) for 0, 1, 2, 3 and 4 h (time-kill) and plated for colony counting (CFU/ml). Active extracts were submitted to exploratory chemical analyses so as to isolate and identify the bioactive compound using spectroscopic methods. The bioactive compound (concentrations ranging from 0.625 to 80 mu g/ml) was then tested through MIC/MBC assays. Peel and seed hexane extracts showed antimicrobial activity against planktonic cells at low concentrations and were thus selected for the time kill test. These hexane extracts reduced S. mutans biofilm viability after 4 h, certifying of the bioactive compound presence. The bioactive compound identified was the polyprenylated benzophenone 7-epiclusianone, which showed a good antimicrobial activity at low concentrations (MIC: 1.25-2.5 mu g/ml; MBC: 10-20 mu g/ml). The results indicated that 7-epiclusianone may be used as a new agent to control S. mutans biofilms; however, more studies are needed to further elucidate the mechanisms of action and the anticariogenic potential of such compound found in R. brasiliensis. (C) 2008 Elsevier GmbH. All rights reserved.
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The application of airborne laser scanning (ALS) technologies in forest inventories has shown great potential to improve the efficiency of forest planning activities. Precise estimates, fast assessment and relatively low complexity can explain the good results in terms of efficiency. The evolution of GPS and inertial measurement technologies, as well as the observed lower assessment costs when these technologies are applied to large scale studies, can explain the increasing dissemination of ALS technologies. The observed good quality of results can be expressed by estimates of volumes and basal area with estimated error below the level of 8.4%, depending on the size of sampled area, the quantity of laser pulses per square meter and the number of control plots. This paper analyzes the potential of an ALS assessment to produce certain forest inventory statistics in plantations of cloned Eucalyptus spp with precision equal of superior to conventional methods. The statistics of interest in this case were: volume, basal area, mean height and dominant trees mean height. The ALS flight for data assessment covered two strips of approximately 2 by 20 Km, in which clouds of points were sampled in circular plots with a radius of 13 m. Plots were sampled in different parts of the strips to cover different stand ages. The clouds of points generated by the ALS assessment: overall height mean, standard error, five percentiles (height under which we can find 10%, 30%, 50%,70% and 90% of the ALS points above ground level in the cloud), and density of points above ground level in each percentile were calculated. The ALS statistics were used in regression models to estimate mean diameter, mean height, mean height of dominant trees, basal area and volume. Conventional forest inventory sample plots provided real data. For volume, an exploratory assessment involving different combinations of ALS statistics allowed for the definition of the most promising relationships and fitting tests based on well known forest biometric models. The models based on ALS statistics that produced the best results involved: the 30% percentile to estimate mean diameter (R(2)=0,88 and MQE%=0,0004); the 10% and 90% percentiles to estimate mean height (R(2)=0,94 and MQE%=0,0003); the 90% percentile to estimate dominant height (R(2)=0,96 and MQE%=0,0003); the 10% percentile and mean height of ALS points to estimate basal area (R(2)=0,92 and MQE%=0,0016); and, to estimate volume, age and the 30% and 90% percentiles (R(2)=0,95 MQE%=0,002). Among the tested forest biometric models, the best fits were provided by the modified Schumacher using age and the 90% percentile, modified Clutter using age, mean height of ALS points and the 70% percentile, and modified Buckman using age, mean height of ALS points and the 10% percentile.
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The present study aimed the preparation and characterization of ternary solid dispersions by direct spray drying of a liquid suspension containing curcumin, a solubility enhancer and a drying aid. The experiments followed a Box-Behnken design in order to evaluate the influence of temperature, ratio of curcumin: lipidic carrier, and the collodial silicon dioxide content on the characteristics of the microparticulated solid dispersions. The angle of repose, Hausner factor, Carr index, water activity, and solubility were used to characterize solid dispersions. The results show that water activity, Hausner factor, and Carr index varied in an acceptable range for pharmaceutical purposes. The condition that maximizes solubility was determined using an exploratory design based on a surface response analysis and allowed a 3200-fold increase in curcumin solubility. Ternary solid dispersion showed a 90% curcumin release after 10min during a dissolution test. The results show that the spray drying of a liquid feed is an attractive and promising alternative to obtain enhanced solubility drug ternary solid dispersions.
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Lead (Pb) is recognized as one of the most toxic metals. Sources of Pb exposure have been widely documented in North America, and the removal of Pb additives from gasoline was reflected in a dramatic lowering of blood Pb concentration. In Latin America, the removal of Pb from gasoline resulted in decreased exposure, but Pb levels in many areas remain high due to occupational and environmental sources of exposure. While many of the Pb sources have been identified (mining, industries, battery recycling, lead-based paint, ceramics), new ones occasionally crop up. Here we report on blood Pb (B-Pb) levels in remote riverside communities of the Brazilian Amazon. Blood Pb (B-Pb) levels were determined in 448 persons from 12 villages of the Lower Tapajos River Basin, Par, Brazil. Socio-demographic and dietary information, as well as occupational, residential and medical history was collected using an interview-administered questionnaire. B-Pb, measured by ICP-MS, showed elevated concentrations. Mean B-Pb was 13.1 mu g/dL +/- 8.5, median B-Pb was 11.2 mu g/dL and ranged from 0.59 to 48.3 mu g/dL. Men had higher B-Pb compared to women (median: 15.3 mu g/dL vs 7.9 mu g/dL respectively). B-Pb increased with age for women, while it decreased for men. For both genders, B-Pb decreased with education. There were significant differences between villages. Exploratory analyses, using linear partition models, showed that for men B-Pb was lower among those who were involved in cattle-raising, and higher among those who hunted, farmed and fished. The distribution profile of B-Pb directed us towards artisanal transformation of manioc to flour (farinha), which requires heating in a large metal pan, with stirring primarily done by young men. In the village with the highest B-Pb, analysis of Pb concentrations (dry weight) of manioc (prior to transformation) and farinha (following transformation) from 6 houses showed a tenfold increase in Pb concentration (mean: 0.017 +/- 0.016 to 0.19 +/- 0.10 mu g/g). This was confirmed in one of these villages where we sampled manioc paste Oust before roasting) and the roasted farinha (0.05 mu g/g vs 0.20 mu g/g). While there may be other sources (ammunition, sinkers for fishing nets), the high concentrations in farinha, a dietary staple, assuredly makes an important contribution. Further action needs to reduce Pb sources in this region. (C) 2009 Elsevier Inc. All rights reserved.
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A combination of deductive reasoning, clustering, and inductive learning is given as an example of a hybrid system for exploratory data analysis. Visualization is replaced by a dialogue with the data.
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This paper reports a comparative study of Australian and New Zealand leadership attributes, based on the GLOBE (Global Leadership and Organizational Behavior Effectiveness) program. Responses from 344 Australian managers and 184 New Zealand managers in three industries were analyzed using exploratory and confirmatory factor analysis. Results supported some of the etic leadership dimensions identified in the GLOBE study, but also found some emic dimensions of leadership for each country. An interesting finding of the study was that the New Zealand data fitted the Australian model, but not vice versa, suggesting asymmetric perceptions of leadership in the two countries.
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While a number of studies have shown that object-extracted relative clauses are more difficult to understand than subject-extracted counterparts for second language (L2) English learners (e.g., Izumi, 2003), less is known about why this is the case and how they process these complex sentences. This exploratory study examines the potential applicability of Gibson's (1998, 2000) Syntactic Prediction Locality Theory (SPLT), a theory proposed to predict first language (L1) processing difficulty, to L2 processing and considers whether the theory might also account for the processing difficulties of subject- and object-extracted relative clauses encountered by L2 learners. Results of a self-paced reading time experiment from 15 Japanese learners of English are mainly consistent with the reading time profile predicted by the SPLT and thus suggest that the L1 processing theory might also be able to account for L2 processing difficulty.
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A reversible linear master equation model is presented for pressure- and temperature-dependent bimolecular reactions proceeding via multiple long-lived intermediates. This kinetic treatment, which applies when the reactions are measured under pseudo-first-order conditions, facilitates accurate and efficient simulation of the time dependence of the populations of reactants, intermediate species and products. Detailed exploratory calculations have been carried out to demonstrate the capabilities of the approach, with applications to the bimolecular association reaction C3H6 + H reversible arrow C3H7 and the bimolecular chemical activation reaction C2H2 +(CH2)-C-1--> C3H3+H. The efficiency of the method can be dramatically enhanced through use of a diffusion approximation to the master equation, and a methodology for exploiting the sparse structure of the resulting rate matrix is established.