941 resultados para Economies of scale
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A large-scale inventory of trees > 10cm DBH was conducted in the upland "terra firme" rain forest of the Distrito Agropecuário da SUFRAMA (Manaus Free Zone Authority Agricultural District) approximately 65Km north of the city of Manaus (AM), Srasil. Thegeneral appearance and structure of the forest is described together with local topography and soil texture. Thepreliminary results of the Inventory provide a minimum estimate of 698 tree species in 53 families in the 40Km radius sampled, including 17 undescribed species. Themost numerically abundant families, Lecythidaceae, Leguminosae, 5apotaceae and Burseraceae as also among the most species rich families. One aspect of this diverse assemblage is the proliferation of species within certain genera, Including 26 genera In 17 families with 6 or more species or morphospecies. Most species have very low abundances of less than 1 tree per hectare. While more abundant species do exist at densities ranging up to a mean of 12 trees per ha, many have clumped distributions leading to great variation in local species abundance. The degree of similarity between hectare samples based int the Coefficient of Community similarity Index varies widely over different sample hectares for five ecologically different families. Soil texture apparently plays a significant role In determining species composition in the different one hectare plots examined while results for other variable were less consistent. Greater differences in similarity indices are found for comparisons with a one hectare sample within the same formation approximately 40Km to the south. It is concluded that homogeneity of tree community composition within this single large and diverse yet continuous upland forest formation can not be assumed.
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A multivariate approach was applied to data of small-scale fisheries developed in Central Amazon, using information about catch composition, environment, fishing gear and season of the hydrological cycle. The correspondence analysis demonstrated to be a good tool for the analysis related multispecies fisheries. The analysis identified patterns of use of fisheries resources by the riverine communities, showing the correlation between the environmental factors and the fishing strategy for the capture of target fish species, indicating the high level of empiric knowledge about the environment and fisheries.
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We investigate palm species distribution, richness and abundance along the Mokoti, a seasonally-dry river of southeastern Amazon and compare it to the patterns observed at a large scale, comprising the entire Brazilian territory. A total of 694 palms belonging to 10 species were sampled at the Mokoti River basin. Although the species showed diverse distribution patterns, we found that local palm abundance, richness and tree basal area were significantly higher from the hills to the bottomlands of the study region, revealing a positive association of these measures with moisture. The analyses at the larger spatial scale also showed a strong influence of vapor pressure (a measure of moisture content of the air, in turn modulated by temperature) and seasonality in temperature: the richest regions were those where temperature and humidity were simultaneously high, and which also presented a lower degree of seasonality in temperature. These results indicate that the distribution of palms seems to be strongly associated with climatic variables, supporting the idea that, by 'putting all the eggs in one basket' (a consequence of survival depending on the preservation of a single irreplaceable bud), palms have become vulnerable to extreme environmental conditions. Hence, their distribution is concentrated in those tropical and sub-tropical regions with constant conditions of (mild to high) temperature and moisture all year round.
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The paper presents three empirical studies designed to extend the test of the construct validity of the Satisfaction With Life Scale (SWLS) among Portuguese students. In the first study, the responses of 461 elementary and secondary education students were submitted to a principal component analysis. A solution of one single factor was chosen, accounting for 55.7 % of the total variance, with Cronbach alpha coefficient and inter-item correlation above .70 and .20, respectively. The second study used a sample of 317 undergraduate students and registered a similar factor solution for SWLS (/pq = 0.99), which accounted for 65.6 % of the total variance (Cronbach alpha .89 and inter-item correlation above .20). A test–retest analysis registered coefficients of .70 (T2) and .77 (T3) and no significant statistically differences between T2, T3 and T1. The third study used a sample of 107 foster care youths from elementary and secondary education. Confirmatory factor analysis results indicate adequate fit indexes for the one-factor solution (v2/df = 2.70, GFI = .96, CFI = .96), which showed convergent validity, reliability and homogeneity. In conclusion, there is psychometric evidence for the one-factor structure of the SWLS in Portugal.
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Modeling clays have been used in several ecological experiments and have proved to be an important tool to variables control. The objective of our study was to determine if fruit color in isolated and grouped displays influences the fruit selection by birds in the field using artificial fruits. Data were collected in six plots distributed homogeneously in 3 km long trails with a minimum distance of 0.5 km. We used a paired experimental design to establish our experiments, so that all treatments were available to the local bird community in each plot. Overall, red was more pecked than brown and white. Isolated red and brown displays were significantly more pecked than others display. Even though our study was conducted in small spatial scales, artificial fruits appeared to be efficient in register fruit consumption attempts by bird. Although inconclusive about selective forces that sharp the dynamics of fruit color polymorphisms and choice by frugivorous birds, our findings corroborate recent studies wherein birds showed preferences by high- over low-contrast fruit signals.
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Quassinoids neosergeolide and isobrucein B, obtained from Picrolemma sprucei, have proven in vitro antitumor, antimalarial, anthelminthic, cytotoxic, insecticide and leishmanicidal activities. There is interest in the in vivo pharmacological study of these natural compounds and their semi-synthetic derivatives, however, the quantities obtained in previous extraction processes have been shown to be a limiting factor for continuation of these studies. Herein, we describe a method for obtaining grams of these quassinoids whose purification relies only on recrystallization.
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Purpose – The purpose of this paper is to develop a subjective multidimensional measure of early career success during university-to-work transition. Design/methodology/approach – The construct of university-to-work success (UWS) was defined in terms of intrinsic and extrinsic career outcomes, and a three-stage study was conducted to create a new scale. Findings – A preliminary set of items was developed and tested by judges. Results showed the items had good content validity. Factor analyses indicated a four-factor structure and a second-order model with subscales to assess: career insertion and satisfaction, confidence in career future, income and financial independence, and adaptation to work. Third, the authors sought to confirm the hypothesized model examining the comparative fit of the scale and two alternative models. Results showed that fits for both the first- and second-order models were acceptable. Research limitations/implications – The proposed model has sound psychometric qualities, although the validated version of the scale was not able to incorporate all constructs envisaged by the initial theoretical model. Results indicated some direction for further refinement. Practical implications – The scale could be used as a tool for self-assessment or as an outcome measure to assess the efficacy of university-to-work programs in applied settings. Originality/value – This study provides a useful single measure to assess early career success during the university-to-work transition, and might facilitate testing of causal models which could help identify factors relevant for successful transition.
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In this contribution, original limit analysis numerical results are presented dealing with some reinforced masonry arches tested at the University of Minho-UMinho, PT. Twelve in-scale circular masonry arches were considered, reinforced in various ways at the intrados or at the extrados. GFRP reinforcements were applied either on undamaged or on previously damaged elements, in order to assess the role of external reinforcements even in repairing interventions. The experimental results were critically discussed at the light of limit analysis predictions, based on a 3D FE heterogeneous upper bound approach. Satisfactory agreement was found between experimental evidences and the numerical results, in terms of failure mechanisms and peak load.
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OBJECTIVE: Bipolar spectrum disorders (BSDs) are prevalent and frequently unrecognized and undertreated. This report describes the development and validation of the Brazilian version of the bipolar spectrum diagnostic scale (B-BSDS), a screening instrument for bipolar disorders, in an adult psychiatric population. METHOD: 114 consecutive patients attending an outpatient psychiatric clinic completed the B-BSDS. A research psychiatrist, blind to the B-BSDS scores, interviewed patients by means of a modified version of the mood module of the Structured Clinical Interview for DSM-IV ("gold standard"). Subthreshold bipolar disorders were defined as recurrent hypomania without a major depressive episode or with fewer symptoms than those required for threshold hypomania. RESULTS: The internal consistency of the B-BSDS evaluated with Cronbach's alpha coefficient was 0.89 (95% CI; 0.86-0.91). On the basis of the modified SCID, 70 patients (61.4%) of the sample received a diagnosis of BSDs. A B-BSDS screening score of 16 or more items yielded: sensitivity of 0.79 (95% CI; 0.72-0.85), specificity of 0.77 (95% CI; 0.70-0.83), a positive predictive value of 0.85 (95% CI; 0.78-0.91) and a negative predictive value of 0.70 (95% CI; 0.63-0.75). CONCLUSION: The present data demonstrate that the B-BSDS is a valid instrument for the screening of BSDs.
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Objective The purpose of this research was to make a cross-cultural adaptation of the Medication Adherence Rating Scale (MARS) for psychiatric patients to the Brazilian context. Methods The procedure consisted of four phases: translation of the original scale, back-translation, review by an Expert Committee and Pre-test study with a patients’ sample. Results The Expert Committee corrected the items’ translation when necessary and modified the scale administration format and its instructions from self-report to face-to-face interview form in order to ensure easy understanding by the target population. During Pre-test, the instructions and most of the items were properly understood by patients, with the exception of three of them which had to be changed in order to ensure better understanding. The Pre-test sample was composed by 30 psychiatric patients, with severe and persistent disorders mainly single (46.7%), female (60.0%), with a mean age of 43.8 years old and an average of five years of education. Conclusion The Brazilian version of MARS scale is now adapted to the Brazilian Portuguese language and culture and is easily understood by the psychiatric target population. It is necessary to do further research to evaluate the scale psychometric qualities of validity and reliability in order to use it in Brazil.
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The use of genome-scale metabolic models has been rapidly increasing in fields such as metabolic engineering. An important part of a metabolic model is the biomass equation since this reaction will ultimately determine the predictive capacity of the model in terms of essentiality and flux distributions. Thus, in order to obtain a reliable metabolic model the biomass precursors and their coefficients must be as precise as possible. Ideally, determination of the biomass composition would be performed experimentally, but when no experimental data are available this is established by approximation to closely related organisms. Computational methods however, can extract some information from the genome such as amino acid and nucleotide compositions. The main objectives of this study were to compare the biomass composition of several organisms and to evaluate how biomass precursor coefficients affected the predictability of several genome-scale metabolic models by comparing predictions with experimental data in literature. For that, the biomass macromolecular composition was experimentally determined and the amino acid composition was both experimentally and computationally estimated for several organisms. Sensitivity analysis studies were also performed with the Escherichia coli iAF1260 metabolic model concerning specific growth rates and flux distributions. The results obtained suggest that the macromolecular composition is conserved among related organisms. Contrasting, experimental data for amino acid composition seem to have no similarities for related organisms. It was also observed that the impact of macromolecular composition on specific growth rates and flux distributions is larger than the impact of amino acid composition, even when data from closely related organisms are used.
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ABSTRACT Objective To perform the psychometric evaluation of the Disordered Eating Attitude Scale (DEAS) for adolescents. Methods Sample consisted of 1,119 Brazilian adolescents (12-18 years old; 59.6% female) studying at technical schools in São Paulo state-Brazil, who answered an online survey with the DEAS, the Eating Attitude Test (EAT-26), and the Restraint Scale (RS). The internal consistency of the DEAS was assessed using Cronbach’s alpha. The convergent validity of DEAS was evaluated by means of Pearson’s coefficient correlation with EAT-26 and RS. The test-retest reliability was evaluated using a sub-sample of 61 adolescents. Known-groups validity was determined by comparing female student mean scores with scores of 33 female adolescents with eating disorders. Results The reliability of the DEAS was 0.79. EAT-26 and RS scores were positively correlated with DEAS scores (EAT: 0.78 for females and 0.59 for males, p < 0.001; RS: 0.63 for females and 0.48 for males, p < 0.001). The DEAS total and subscale scores differentiated students and patients with eating disorders (p < 0.001). The intra-class correlation coefficient for test-retest reliability was 0.87. Conclusion Results indicate that the DEAS adolescent version showed good internal consistency, convergent validity, known-groups validity, and test-retest reliability, suggesting its potential in identifying disordered eating attitudes among adolescents. It could also be helpful in identifying adolescents at risk from eating disorders, assisting in prevention programs.
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OBJECTIVE: To compare sleepiness scores of the Epworth scale in patients with different levels of arterial pressure when undergoing outpatient monitoring within the context of clinical evaluation. METHODS: A total of 157 patients selected for outpatient monitoring of arterial pressure during hypertension evaluation were divided into 3 groups: group 1 - normotensive; group 2 - hypertensive; group 3 - resistant hypertensive. For analysis, values > or = 11 were considered as associated with respiratory disturbances during sleep. RESULTS: Seventeen (10.8%) patients in group 1, 112 (71.3%) in group 2, and 28 (17.8%) in group 3, which was composed of aged, more severely hypertensive individuals, were analyzed. Groups were similar relative to sex and body mass index, but different in relation to systolic and diastolic pressure levels and age. Despite an absolute difference, no statistically significant difference occurred between Epworth scores and in the proportion of patients with values > or = 11 (5.9% vs. 18.8% vs. 212.4%; P=0.37). Despite the positive association between degree of sleepiness measured with the scale and the severity of the hypertension, no statistical significance occurred following control by age (p=0.18). CONCLUSION: A positive correlation exists between degree of sleepiness and hypertension severity. The absence of a statistical significance shown in the present study could be due to a beta type of error. Instruments that render this complaint into an objective finding could help in the pursuit of an investigation of respiratory disturbances during sleep in more severely hypertensive patients, and should therefore be studied better.
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Programa Doutoral em Engenharia Mecânica.
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Uno de los problemas que es más debatido a nivel país resulta ser todo lo que atañe a la balanza de pagos. Sin embargo, lamentablemente esta preocupación se abandona cuando bajamos a los niveles provinciales. El problema en concreto surge a nivel provincial como consecuencia de que efectivamente, en el largo plazo, la Balanza de Pagos Regional (BPR) debe estar equilibrada, por lo que en los casos en que las provincias atraviesen por una situación de déficit crónicos (que revelan desequilibrios), tal situación se cubre con capitales extraprovinciales. Como es consenso, para salvar esos déficit crónicos las economías deben alcanzar un estadio de crecimiento autogenerado (es decir, financiado con su propio ahorro), que permita un nivel suficiente de PBG, y para ello deberá operar un "proceso de convergencia" respecto a las áreas más desarrolladas. Sin embargo, los estudios demuestran que no se observa tal proceso de convergencia en las provincias argentinas. Surge la pregunta de por qué no ha operado esa convergencia que equilibre económicamente el mapa espacial de nuestra economía (aproximando los niveles de ingreso por habitante, y superando la Restricción Externa Regional).Una probable respuesta a esta falta de convergencia está en la presencia de las transferencias interjurisdiccionales desde las provincias más ricas a las más pobres. En Argentina, esto ha ocurrido históricamente a través del régimen de coparticipación (el cual permite al gobierno nacional redistribuir recursos entre provincias). Pero lo paradójico es que este flujo podría resultar en verdad un factor de estancamiento, vía la "enfermedad holandesa". Precisamente, un interrogante a dilucidar que pretende explorar esta investigación es la posibilidad de que la existencia de un sistema de transferencias fiscales, fuertemente redistributivo (tal como funciona en Argentina) genere un fenómeno tipo enfermedad holandesa en las jurisdicciones subnacionales, deteriorando las posibilidades de crecimiento en las provincias más beneficiadas por el reparto de la renta fiscal nacional.