355 research outputs found
Desempenho acad?mico de alunos de 9? ano na Geometria Espacial: impacto de vari?veis pessoal e de contexto
This article presents and discusses results from a study investigating the quality of Spatial Geometry academic performance of 9th grade students when they are about to be exposed to more complex concepts, geometric solids, and related problems in curricular learning experiences. Participants were Portuguese public school students. We also collected information about previous mathematics grades and mother?s schooling. A geometry test, a causal attribution to a school achievement test, and two reasoning tests ? spatial and mechanical ? were applied, and all collected data was statistically analysed and interpreted. To address the different nature of variables, we conducted a hierarchical linear regression. Results suggest that nearly 41% of variance on Spatial Geometry academic performance can be explained by the personal and contextual variables studied. The recommendation to schoolteachers involves designing learning experiences that engage students in spatial reasoning and high-order thinking skills.AF10-A514-BE72 | Luciana Pereira de BritoN/
Assessment of RC hollow-piers for seismic limit state of damage - Direct repair costs
Due to the vulnerability of reinforced concrete hollow piers subjected to seismic actions, it becomes urgent to assess the expected shear damage and its evolution with the increase of the intensity level. Additionally, the focus of the scientific research dedicated to seismic behaviour of these elements is still reduced, in particular with regard to the limit states of damage and to the economic consequences of repairing and retrofitting the physical damages existing in RC hollow piers subjected to the seismic action. This information is deemed crucial when cost-benefit analysis is concerned for the definition of measures for repair and retrofit of seismic damage. This paper focus on the issue of damage to hollow piers due to the seismic action, proposing a methodology to characterize the limit states of damage under the perspective of the physical behaviour. It also intends to discuss adequate strengthening strategies and their direct costs, associated with each seismic physical limit state of damage. An extensive review of numerous cyclic experimental works on RC hollow piers will be performed, and in liaise with specialized construction companies, the direct repair costs will be estimated.6612-034D-AE05 | PEDRO DA SILVA DELGADON/
Hybrid model associating thermodynamic calculations and artificial neural network in order to predict molten steel temperature evolution from blowing end of a BOF for secondary metallurgy.
The developed model is an association of thermodynamic calculations for dissolution
of alloys, slag formers and the deoxidation reaction in the molten steel with
two artificial neural network (ANN) models trained with industrial data, to predict
the molten steel temperature drop from the blowing end of the BOF until the first measurement
at secondary metallurgy. To calculate the associated energy for deoxidation,
an experiment was designed to set up the parameters for oxygen partitioning among
deoxidants, with timed aluminum addition during teeming being the main parameter.
The temperature control in the teeming stage presented a standard deviation for the
error of prediction of 5.46 oC, for transportation from the rinsing station to the secondary
metallurgy of 2.79 oC. The association of all calculations presented an error
standard deviation of 7.49 oC. The operational validation presented superior accuracy
compared with the current method for controlling the temperature, resulting in a reduction
in the aluminum consumption for heating at secondary metallurgy with a
potential economy of U$ 4.07 million per year for a steel shop producing 5 million tons
of steel yearly. The artificial neural network model confirmed its capacity for modeling
a complex multivariable process and the separation of thermodynamic calculation
provides a better adaptability to different steel grades with different teeming strategies
Para al?m do figurino : ?peles em processo? como dispositivo criativo para atores e atrizes na sala de ensaio.
Programa de P?s-Gradua??o em Artes C?nicas. Instituto de Filosofia, Artes e Cultura, Universidade Federal de Ouro Preto.A presente disserta??o discorre sobre quest?es relacionadas ao figurino teatral como elemento
fundamental do discurso c?nico. Considera os diversos elementos que envolvem a pele do
ator/performer como constituintes de uma segunda pele, capaz de conduzir, estimular e
alimentar a concep??o c?nica, a partir das provoca??es feitas sobre seu corpo na sala de
ensaio. Examina tamb?m outros dispositivos de cria??o: as peles plurais formadas pelos
elementos est?ticos da encena??o ? caracteriza??o, ilumina??o, adere?os cenogr?ficos, etc.,
aqui denominados de ?peles em processo?. A pesquisa dialoga com o conceito de ?eu-pele?,
do psicanalista Didier Anzieu; com a concep??o de ?cinco peles?, do pintor austr?aco
Friedensreich Hundertwasser, referida pelo cr?tico de arte Pierre Restany e com o conceito de
?Teatro performativo?, da pesquisadora Josette F?ral. S?o analisadas quatro pr?ticas
processuais de obras c?nicas/performativas pela ?tica dos conceitos referidos.The present dissertation discusses issues related to theatrical costumes as a fundamental element of
the scenic discourse. It considers the various elements that involve the skin of the actor/performer as
constituents of a second skin, capable of conducting, stimulating and feeding the scenic conception,
from the provocations made on his body in the rehearsal room. It examines also other devices of
creation: the plural skins formed by the aesthetic elements of the staging ? characterization, stage
lighting, scenographic props, etc., hereinafter ?skin in process?. The research dialogues with the
concept of ?Skin-Ego?, of the psychoanalyst Didier Anzieu; with the "Five Skins" conception of the
Austrian painter Friedensreich Hundertwasser, referred to by the art critic Pierre Restany and the
concept of ?performative theater? by the researcher Josette F?ral. Four procedural practices of
scenic / performative works are analyzed from the perspective of the referred concepts
Carbonyl group generation on single-wall carbon nanotubes with nitric acid: A theoretical description
AbstractThe initial steps of single-wall carbon nanotube (SWNT) oxidation in nitric acid were studied using a (6,6) supercell with a mono-vacancy defect and employing spin-polarised density functional theory. According to our results, the geometric changes that occur during the process are significantly localised around the vacancy. The carbonyl group generation does not change the metallic nature of the nanosystem. Vibrational thermal corrections calculated using full and partial Hessian vibrational analysis indicated a small contribution to the reaction energy. An overall favourable oxidation pathway is proposed and includes an initial NO2+ exothermic electrophilic attack followed by an endothermic oxaziridine formation
O impacto da pol??tica do ICMS Esportivo sobre a gest??o esportiva municipal de Minas Gerais
O ICMS Esportivo ?? uma pol??tica institu??da pelo governo de Minas Gerais para repassar aos munic??pios os recursos oriundos do Imposto sobre Opera????es Relativas ?? Circula????o de Mercadorias e sobre Presta????es de Servi??os de Transporte Interestadual, Intermunicipal e de Comunica????o (ICMS). Os munic??pios participantes recebem os recursos de acordo com suas realiza????es no esporte municipal e, desde sua cria????o, em 2009, essa pol??tica tem contribu??do para o aumento no n??mero de praticantes, modalidades e atividades esportivas oferecidas no Estado. Tendo em vista que ?? pr??-requisito para participa????o no ICMS Esportivo que o munic??pio possua um conselho municipal de esportes em funcionamento, este estudo tem como objetivo analisar o impacto dessa pol??tica na gest??o esportiva municipal, dando enfoque ?? rela????o estabelecida entre o poder p??blico municipal e o Conselho Municipal de Esportes
Circunfer?ncia do pesco?o e risco cardiovascular em 10 anos : diferen?as por sexo. an?lise seccional da linha de base do Estudo Longitudinal de Sa?de do Adulto (ELSA-Brasil).
Programa de P?s-Gradua??o em Sa?de e Nutri??o. Escola de Nutri??o, Universidade Federal de Ouro Preto.INTRODU??O: A circunfer?ncia do pesco?o (CP) ? uma estimativa da gordura do pesco?o e da gordura subcut?nea da parte superior do corpo, cujo aumento parece conferir risco cardiovascular adicional ?quele conferido pela adiposidade geral e abdominal. O Framingham Global Risk Score (FGRS) fornece uma estimativa do risco de desenvolver DCV em 10 anos, utilizado para identificar indiv?duos sob maior risco de DCV, inclusive na pr?tica cl?nica. OBJETIVO: O objetivo da presente disserta??o foi verificar a associa??o entre a circunfer?ncia do pesco?o e o risco de evento cardiovascular em 10 anos em homens e mulheres participantes da linha de base do Estudo Longitudinal de Sa?de do Adulto (ELSA-Brasil). M?TODOS: Trata-se de estudo de corte transversal com participantes da linha de base do Estudo Longitudinal de Sa?de do Adulto (ELSABrasil) (2008-2010). O ELSA-Brasil ? uma coorte multic?ntrica com 15.105 servidores p?blicos, ativos e aposentados de institui??es de ensino e pesquisa de seis capitais de estados brasileiros. Para a presente an?lise, foram exclu?dos os indiv?duos com relato de DCV (n=738) e sem informa??es para DCV (n=26), CP (n=11), FGRS (n=28) e covari?veis (n=382), permanecendo 13.920 participantes. As caracter?sticas da popula??o do estudo e dos componentes do FGRS foram descritas por meio de frequ?ncias absolutas e relativas, m?dias e desvio padr?o (?DP) ou medianas (1? e 3? quartis) e utilizados testes compara??o dessas medidas. A associa??o entre a CP (utilizada como vari?vel cont?nua e agrupda em quartis) e o risco DCV em 10 anos, mensurado pelo FGRS, foi estimada por meio de Modelos Lineares Generalizados (MLG), com distribui??o gama e fun??o logar?tmica, cujo exponencial do coeficiente de regress?o fornece a Raz?o da M?dias Aritm?ticas com intervalo de 95% de confian?a (RMA, IC95%). Foram realizados ajustes por idade, escolaridade, ra?a/cor autorreferida, consumo de ?lcool, atividade f?sica no lazer, ?ndice de massa corporal (IMC) e circunfer?ncia da cintura (CC). RESULTADOS: A m?dia de idade dos participantes foi de 51,7 anos (DP?7,6), sendo 55% mulheres. A m?dia da CP aumentou com o incremento do risco de DCV em 10 anos agrupado em categorias de risco (risco baixo 20%) em ambos os sexos. Ap?s todos os ajustes, incluindo as demais medidas de adiposidade corporal, a CP permaneceu independentemente associada a um aumento de 3% na m?dia aritm?tica do risco DCV em 10 anos (RMA= 1,03; IC 95% 1,01-1,03) nos homens e de 5% (RMA= 1,05; IC 95% 1,04-1,06) nas mulheres. Nos modelos de regress?o utilizando a CP agrupada em quartis, ap?s todos os ajustes, observamos que comparados ao primeiro quartil todos os demais apresentaram aumento gradual na m?dia aritm?tica no risco de DCV em 10 anos, que chegou a um incremento de 18% entre os que estavam no ?ltimo quartil (IC95%: 1,13-1,24) entre os homens e a 35% (IC95%: 1,28-1,43) entre as mulheres. Foram realizadas an?lises de sensibilidade com a exclus?o de participantes em uso de hipolipemiantes, uso de corticoides, e de mulheres em uso de anticoncepcional ou em reposi??o hormonal e essas exclus?es n?o levaram a altera??o nos resultados observados. CONCLUS?O: Nossos resultados sugerem uma associa??o entre a circunfer?ncia do pesco?o e o risco DCV em 10 anos, mensurado pelo Framingham Global Risk Score em ambos os sexos, mas indicando maior for?a de associa??o entre as mulheres. Contudo, novos estudos em outras popula??es e an?lises longitudinais s?o necess?rios.INTRODUCTION: The effect of adipose tissue on the development of CVD varies between different fat deposits. Neck Circumference (NC) provides an estimate of neck fat and upper body subcutaneous fat that has been singled out as the sole body fat deposit that confers additional cardiovascular risk above and beyond general and central body fat. OBJECTIVE: The objective of this dissertation was to verify the association between neck circumference and cardiovascular risk in 10 years in men and women participants from the baseline of the Longitudinal Study of Adult Health (ELSA-Brazil). METHODS: A cross-sectional study was conducted with participants from the Study of the Longitudinal Study of Adult Health (ELSA-Brazil) baseline (2008-2010). ELSABrazil is a multicentre cohort composed of 15,105 civil serventes from institution of education and research institutions in six Brazilian state capitals. For the present analysis, individuals with a history of CVD (acute myocardial infarction, heart failure, stroke and coronary artery bypass grafting) (n = 738), missing information for CVD (n = 26), for NC = 11), for the Framingham Global Risk Score (n = 28) and for covariables (n = 382) were excluded. At the end the sample analytic was composed by 13,920 participants.The characteristics of the study population and the FGRS components were described by means of absolute and relative frequencies (categorical variables) and means and standard deviation (? SD) or medians (1st and 3rd quartiles) (continuous variables). Pearson's Chisquare test was used for comparison of frequencies, Student's t-test for comparison of means and Kruskal-Wallis test for comparison of medians. The association between NC (continous variable and agrouped in quartiles) and the10-years CDV risk, measured by the FGRS, was estimated using Generalized Linear Models (MLG), with gamma distribution and logarithmic function, whose exponential regression coefficient gives the Arithmetic Mean Ratio with 95% confidence interval (RMA, 95% CI). Potential confounding factors were age, schooling, self-reported race / color, alcohol consumption, leisure time physical activity, body mass index (BMI) and waist circumference (WC). RESULTS: The mean age of participants was 51.7 years (SD ? 7.6), being 55% female. The mean NC increased according to risk categories of the 10-year CVD risk (low risk 20%) in both sexes. In the crude analysis, it was observed that the increase of one centimeter in NC was associated with an increase of 5% (RMA = 1.05, 95% CI: 1.04-1.05) in the mean 10-year CVD risk in men and 11% (RMA = 1.11, 95% CI: 1.10-1.12) in women. After all the adjustments, including the other measures of body adiposity, NC remained independently associated with a 3% increase in the arithmetic mean of CVD risk in 10 years (RMA = 1.03, 95% CI, 1.01- 1.03) in men and 5% (RMA = 1.05, 95% CI 1.04-1.06) in women. In the regression models using NC grouped in quartiles, after all the adjustments, we observed that, compared to the first quartile, all the others presented a gradual increase in the arithmetic mean in the risk of the 10-years CVD risk, which reached an increase of 18% in men who were in the last quartile (95% CI: 1.13-1.24) and 35% (95% CI: 1.28-1.43) in women. Sensitivity analyzes were performed with the exclusion of participants taking lipidlowering drugs, corticosteroids, and women taking contraceptives or hormone replacement, and these exclusions did not lead to alteration in the observed results. CONCLUSION: Our results suggest an association between NC and 10-years CVD risk as measured by the Framingham Global Risk Score in both sexes, but indicating a greater strength of association among women
Pt(IV)/Re(I) Chitosan Conjugates as a Flexible Platform for the Transport of Therapeutic and/or Diagnostic Anticancer Agents
New chitosan derivatives modified with (3-carboxypropyl) trimethylammonium chloride (1) and coupled with (OC-6-44)-diammine(4-carboxypropanoato) dichloridoethanolatoplatinum(IV) (2), were synthesized and their preliminary biological evaluation carried out in human tumor cells. Some of these derivatives were also loaded with a chelating ligand (3) that was derived from bis(quinolin-2-ylmethyl) amine to obtain chitosan-based nanoparticles for an EPR-mediated delivery of Pt(IV) prodrugs and Re(I) tricarbonyl complexes (4), to explore a multimodal theranostic approach to cancer. The cytotoxicity of the different chitosan conjugates (C12, C123, and C1234), carrying different combinations of the Pt(IV) complex, the chelator and the Re(I) complex, was evaluated in the A2780 human ovarian cancer cell line using the MTT assay. The Pt(IV)-containing nanosystems showed low to moderate cytotoxic activity (IC50 values in the range 13.5-33.7 uM) and was comparable to that found for the free Pt(IV) complex (IC50 = 13.7 uM). Therefore, the Pt(IV)-chitosan conjugation did not enhance the cytotoxic activity of the Pt(IV) prodrug, which certainly reflects the inefficient cellular uptake of the nanoconjugates. Nevertheless, a clearer view of their potential for the delivery of anticancer agents requires further in vivo tests because the EPR effect increases extravasation and retention within the tumor tissue, not necessarily within the tumor cells
Nickel and cobalt adsorption in an ion exchange resin as an alternative for treating the leached liquer.
Estudou-se o emprego da resina PUROLITE S-930 como substrato para a remo??o de n?quel e cobalto de solu??es sulf?ricas. Experimentos de adsor??o com diferentes raz?es [Ni]/[Co] mostraram uma maior sele??o da resina em solu??es mais ricas em n?quel (Ni 600 mg/L - Co 800 mg/L). Isotermas de adsor??o mostraram um aumento na capacidade de adsor??o da resina em temperaturas mais elevadas (qmax Ni 0,28 mol/L, a 70?C e qmax Co 0,18 mol/L, a 60?C). Os valores de ?H indicaram uma fisiossor??o endot?rmica. Para modelar a cin?tica de carregamento da resina, em leito fixo, utilizou-se o modelo de difus?o superficial homog?nea (Homogeneous Surface Diffusion Model - HSDM). Os resultados mostram um bom ajuste ao modelo, com kf = 5,2x10-6 m/s e DS = 4,5x10-12 m2/s, indicando que o carregamento da resina baseia-se em difus?o na camada-limite e difus?o nos poros da resina.A study concerning the resin PUROLITE S-930 as a substrate to remove nickel and cobalt from sulphuric solution is herein presented. The influence of nickel and cobalt concentrations was studied, and the results have shown a greater selection of the resins for solutions rich in nickel (Ni 600 mg/L - Co 800 mg/L). The adsorption isotherms showed an increase in the resin adsorption capacity at higher temperatures (qmax Ni 0.28 mol/L, at 70?C and qmax Co 0.18 mol/L, at 60?C). The enthalpy values suggested endothermic physisorption. The Homogeneous Surface Diffusion Model (HSDM) was chosen for modeling the adsorption kinetics of metals in a fixed-bed column. The results showed good agreement with the model. Both, kf = 5.2x10-6 m/s and DS = 4.5x10-12 m2/s indicated that resin loading is based on transport through the boundary layer and porous diffusion in the resin
Soil fauna through the landscape window: factors shaping surface-and soil-dwelling communities across spatial scales in cork-oak mosaics
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