Atividades experimentais investigativas propostas por professores de Química em uma ação formativa reflexiva

Atividades experimentais são consideradas pelos professores de química como fundamentais no ensino. Enretanto, utilizam abordagens tradicionais focadas na comprovação de conceitos e roteiros altamente estruturados, com baixa participação dos alunos. Considerando as limitações deste tipo de prática e que os professores têm dificuldades em propor e analisar atividades experimentais baseadas na investigação foi realizadoum processo formativo de reflexão orientada, no qual os professores avaliassem seus próprios roteiros. Neste trabalho foram analisadosos roteiros elaborados e reelaborados por três professores, com base em atividades de natureza investigativa. Os resultados mostram que osprofessores evoluíram de forma gradativa, considerando em seus roteiros alguns dos elementos pedagógicos que caracterizam atividades de natureza investigativa

Experimental relations between stress and fracture properties on synthetic anisotropic media

Summary Elastic anisotropy due to aligned cracks has been the subject of many seismic physical modeling experiments. In earlier investigations, different experimental approaches have taken into account the size, shape and density of cracks. In this paper we present a physical study of the aspect ratio as a function of applied uniaxial stress. We carried out pulse transmission measurements of P-and Swave velocities in a reference model without inclusions and in a model with penny-shaped neoprene inclusions. The reference model is an anisotropic matrix that consists of stacked plexiglass plates. Rubber discs were used as inclusions in that anisotropic matrix leading to secondary anisotropy. We recorded ultrasonic seismic data using Pwave transducers with central frequency 120 kHz and Swave transducers with 90 kHz. We compressed the physical models using pressures ranging from 3 to 15.8 MPa. Full crack closure occurs at stress 14.6 MPa normal to model faces. Our analysis indicates three different regimens for the behavior of the inclusions. These results suggest a different dependence of the crack aspect ratio on uniaxial stress at the low state of stress than usually described in the literature. Though our results are not extensive, they show that simple experimental approaches might provide valuable insight into the behavior of cracked rocks at reservoir stress levels

Efeito do polimorfismo Thr92Ala da enzima desiodase tipo 2 no comportamento adaptativo de indivíduos com Transtorno do Espectro Autista

O Thr92Ala é um polimorfismo da D2, enzima cuja principal função é converter T4 em T3, forma biologicamente ativa do hormônio tireoidiano. Esse polimorfismo tem sido relacionado a transtornos como Esquizofrenia, Depressão e Alzheimer, e foi demonstrado que em indivíduos homozigotos para o polimorfismo existe uma alteração no padrão de expressão de genes ligados aos processos neurodegenerativos e estresse oxidativo no Sistema Nervoso Central (SNC). Estudos com indivíduos com Transtorno do Espectro Autista (TEA) têm demonstrado que esses pacientes apresentam maior estresse oxidativo celular. Assim, o objetivo desse estudo foi avaliar se pacientes com TEA que apresentavam o polimorfismo teriam piores resultados nas avaliações cognitivas e comportamentais quando comparados aos pacientes que não apresentavam o polimorfismo. Foram avaliados 132 pacientes com TEA atendidos em unidade de referência e foram avaliados os resultados obtidos no Autism Behavior Checklist (ABC), Escala Vineland de Comportamento adaptativo, testes de QI e em duas avaliações de Autism Treatment Evaluation Checklist (ATEC). Foi possível observar que os pacientes que expressavam o alelo polimórfico em homozigose tiveram melhor desempenho que os pacientes com genótipo selvagem nos seguintes parâmetros: Comunicação, Comunicação Receptiva, Atividades de vida diária e Autocuidado, e pacientes com genótipo selvagem e com piores resultados no ABC obtiveram melhora significativa nas habilidades de socialização avaliadas pela ATEC após a intervenção. Portanto, a presença do polimorfismo melhora o desempenho adaptativo dos indivíduos, mas parece prejudicar a resposta do paciente à terapia proposta. Mais estudos são necessários para aumentar a compreensão acerca do papel dessa enzima e os mecanismos pelos quais o polimorfismo altera o funcionamento do SNC, tanto para indivíduos de desenvolvimento típico quanto para aqueles com algum distúrbio do desenvolvimento.Thr92Ala D2 it’s the polymorphism of a thyroid hormone enzyme responsible to convert T4 in its active form, T3. This polymorphism has been related to Schizophrenia, Depression and Alzheimer’s disease, and its been shown that in the presence of both polymorphic alleles there’s a difference in the expression of genes relates to neurodegenerative process and oxidative stress in Central Nervous System (CNS). Studies with Autism Spectrum Disorder (ASD) patients has demonstrated that in this group, cells are more likely to present oxidative stress condition. The aim of this study was to evaluate whether ASD patients expressing Thr92Ala-D2 polymorphism would have poorer results at cognitive and behavioral tests when compared with patients without the polymorphism. Were assessed 132 ASD patients and the results of Autism Behavior Checklist (ABC), Vineland Scale of Adaptative Behavior, IQ and Autism Treatment Evaluation Checklist (ATEC). The analyses showed that patients expressing the polymorphism had better performances in Communication, Receptive Communication, Daily Living and Selfcare, although patients with wild genotyping and more critical ABC results had significative improvement of their social skills after interventions. Therefore, the existence of polymorphism improves adaptative performance in ASD patients, however the polymorphism seems to impair patient’s response to therapies. More researches are necessary in order to improve the comprehension of enzyme’s role and mechanisms underlying polymorphism’s CNS fingerprint

Correlações entre características relacionadas ao temperamento em animais da raça Canchim.

O temperamento de um animal representa uma interação complexa entre seu genótipo e o ambiente ao qual está exposto. Medidas de temperamento diferentes e realizadas sob diferentes metodologias podem ser aplicadas aos programas de seleção. O objetivo do trabalho foi obter correlações fenotípicas e de ranking entre reatividade e escores de temperamento relacionados ao deslocamento e à tensão na balança de animais da raça Canchim pertencentes a um programa de melhoramento. Dados de 217 animais da safra 2012 foram avaliados à desmama, na balança, por meio de escores de deslocamento (DES10 e DES20) e de tensão (TEN10 e TEN20) aos 10 e aos 20 segundos e do número e intensidade de movimentos do animal (REAT) quantificados por meio de equipamento e software específicos. As correlações foram obtidas por meio do pacote estatístico SAS, tanto para os dados gerais, quanto por sexo e para os grupos de avaliação (de 1 a 4). De maneira geral, as correlações fenotípicas e de ranking entre REAT, TEN10, TEN20, DES10 e DES20 foram altas e positivas, indicando concordância entre as metodologias na avaliação de animais desmamados da raça Canchim. Outras avaliações serão realizadas em idades posteriores e até a finalização do projeto com outras safras, em 2017

On complexity and convergence of high-order coordinate descent algorithms

Coordinate descent methods with high-order regularized models for box-constrained minimization are introduced. High-order stationarity asymptotic convergence and first-order stationarity worst-case evaluation complexity bounds are established. The computer work that is necessary for obtaining first-order $\varepsilon$-stationarity with respect to the variables of each coordinate-descent block is $O(\varepsilon^{-(p+1)/p})$ whereas the computer work for getting first-order $\varepsilon$-stationarity with respect to all the variables simultaneously is $O(\varepsilon^{-(p+1)})$. Numerical examples involving multidimensional scaling problems are presented. The numerical performance of the methods is enhanced by means of coordinate-descent strategies for choosing initial points

Political leadership and ‘non-traditional’ development cooperation

This article explores the relationships between (so-called) ‘non-traditional’ development cooperation (NTDC) and political leadership. Using the case studies of Brazil and South Korea, we propose that certain emblematic elements of NTDC discourse and practice can act to influence the relationship with political leaders in particular ways. These are (a) elevated language of affect, (b) interleaving of personal biographies with the developmental trajectories of states, (c) the use of NTDC to legitimise domestic policies and promote domestic political leadership, (d) the prominence of presidential diplomacy and (e) the challenges confronting rapidly expanding domestic development cooperation institutions and systems

Marginal adaptation of class V composite restorations submitted to thermal and mechanical cycling

Objective This study evaluated the effect of the margin location and an adhesive system on the marginal adaptation of composite restorations. Material and Methods Class V cavities were prepared in bovine teeth with the gingival margin on the dentin and the incisal margin on the enamel. The cavities were restored with a micro-hybrid composite resin using an etch-and-rinse [Single Bond 2 (SB)] or a self-etching adhesive [Clearfil SE Bond (CL)]. After finishing and polishing the restorations, epoxy replicas were prepared. The marginal adaptation was analyzed using scanning electronic microscopy (SEM, 500 x magnification). The higher gap width in each margin was recorded (T0). After the first evaluation, the samples were submitted to thermal cycling (2,000 cycles of 5°C±2°C followed by 55°C±2°C – T1) and mechanical cycling (100,000 cycles of 50 kN and 2 Hz – T2). Replicas of samples were rebuilt after each cycling and analyzed under SEM. The data were submitted to Mann-Whitney, Wilcoxon and Friedman testing (α=0.05). Results The SB presented higher gaps in the dentin than the enamel, while there was no difference between the substrate for the CL. In the dentin, the CL showed better marginal sealing than the SB. The opposite occurred in the enamel. There were no significant differences between the baseline, thermal and mechanical cycling for any experimental condition. Conclusions The outcomes of the present study showed that the adhesive system and margin location have an important effect on the marginal adaptation of composite restorations

The kinetics of chondroitin 4-sulfate release from stimulated platelets and its relation to thromboxane A2 formation and granule secretion

1. In platelet rich plasma (PRP), chondroitin 4-sulfate release from platelets occurred after stimulation with ADP (5 microM), collagen (5-10 micrograms/ml), or adrenaline (10 microM). Release started within 60 s and maximum release (0.7-2.0 mg/l) was reached within 180 s. TXA2 formation and dense granule release reached a maximum within 90 s after stimulation. 2. Using washed platelets (1.5 x 10(8) cells/ml), the platelet responses were faster. Release of chondroitin 4-sulfate and TXA2 started within 20-30 s after thrombin addition (100 mU/ml). Maximum release was reached within 60 s in both cases. Dense granule release started in the first 5 s of stimulation (34.6 +/- 12.4%) reaching maximum secretion (74.4 +/- 8.7%) within 60 s. 3. Our results demonstrate that maximal chondroitin 4-sulfate release occurs after the dense granule release reaction in both PRP and washed platelets. This observation suggests that chondroitin 4-sulfate is unlikely to be stored in the dense granules but may be stored in the alpha-granules.In platelet rich plasma (PRP), chondroitin 4-sulfate release from platelets occurred after stimulation with ADP (5 microM), collagen (5-10 micrograms/ml), or adrenaline (10 microM). Release started within 60 s and maximum release (0.7-2.0 mg/l) was reached within 180 s. TXA2 formation and dense granule release reached a maximum within 90 s after stimulation. 2. Using washed platelets (1.5 x 10(8) cells/ml), the platelet responses were faster. Release of chondroitin 4-sulfate and TXA2 started within 20-30 s after thrombin addition (100 mU/ml). Maximum release was reached within 60 s in both cases. Dense granule release started in the first 5 s of stimulation (34.6 +/- 12.4%) reaching maximum secretion (74.4 +/- 8.7%) within 60 s. 3. Our results demonstrate that maximal chondroitin 4-sulfate release occurs after the dense granule release reaction in both PRP and washed platelets. This observation suggests that chondroitin 4-sulfate is unlikely to be stored in the dense granules but may be stored in the alpha-granules2792163216