Importance of Elastic Recovery in the DSR for Binders and Mastics

Elastic Recovery (ER) is used by many highway agencies for modified bitumen grading specifications. The current ASTM/AASHTO standards for ER testing utilize the ductility bath as the measurement apparatus. A new procedure for measuring the elastic recovery in the Dynamic Shear Rheometer (ER-DSR) was developed and was used to test different polymer modified binders and mastics. The results show a good correlation between the ER-DSR and ER measured in the ductility bath (ER-DB). The ER-DSR requires less material and is more time efficient and repeatable than the ER-DB. Since the link between the ER measurements and pavement performance is not well established, the study compared ER measurements with binder rutting and fatigue results as measured by the Multiple Stress Creep and Recovery (MSCR) test and the linear amplitude sweep (LAS) test, respectively. Generally, binders and mastics with higher ER-DSR value showed higher percent recovery (MSCR) and fatigue resistance (LAS). This study also showed the effect of natural and manufactured fillers on the percent recovery measured with the MSCR test. Based on the experimental results, it is recommended to replace ER-DB with the ER-DSR. Also, agencies should consider the MSCR and fatigue tests as indicators of binder modification rather than the ER, as they provide direct measurements of damage resistance characteristics for which the elastic recovery might not indicate

Portuguese Adaptation of Students Engagement in Schools International Scale (SESIS)

The importance of student’s engagement has been recently pointed out in research. However, there has been a lack of engagement assessment instrument, pertaining psychometric qualities. Objective: This paper presents the Portuguese adaptation of the “Student’s Engagement in School International Scale” (SESIS), drawn up from a12 countries international study (Lam et al., 2012; Lam et al., in press). Method: Psychometric properties of this scale were examined with data from 685 students from different grades (6th, 7th, 9th and 10th), from both sexes, and different regions of the country. Results: Factorial analysis of the results, with varimax rotation, lead to three different factors which explain 50.88% of the variance. The scale integrates the original 33 items, and cognitive, affective and behavioural dimensions. For the external validity study, the relationship between student’s engagement in school results and other school variables — academic performance, self-concept — was considered, and significant relations were observed, as expected. Conclusion: The data presented highlights the qualities of SESIS, as well as its usefulness for research purposes. Suggestion: It is suggested the investigation of the extension of SESIS’s three-dimensionality, in future studiesKeywords: Innovation, technology, research projects, etc. [Arial 10-point, justified alignment]

Students’ engagement in school and creativity professed by students and assigned to teachers: A literature review

Este E-Book reúne um conjunto de investigações apresentadas no “I Congresso Internacional Envolvimento dos Alunos na Escola: Perspetivas da Psicologia e Educação” (ICIEAE), organizado no âmbito do “Projeto PTDC/CPE-CED/114362/2009 - Envolvimento dos Alunos na Escola: Diferenciação e Promoção” (EAE-DP), financiado pela Fundação para a Ciência e a Tecnologia (FCT).This article reviews the literature on the relation between creativity (as a personal and a contextual variable) and students’ engagement in school. In order to describe the state of art of student’s engagement in school and creativity, we prepared a narrative review. In general, literature shows a prevalence of studies relating creativity and giftedness; students with above average skills are, as a rule, characterized, among other criteria, by the presence of creativity and the existence of high motivation for learning. As a personal variable, creativity relates positively with self-concept and academic performance, appearing as an aspect worth encouraging in the student. Moreover, studies on the impact of the learning environments on student’s performance also suggest a positive relationship between the classroom climate and academic outcomes. Although studies on the relationship between creativity and the students’ behavior appear inconsistent, the teacher’s creativity, applied to the teaching-learning process, and perceived by the student, appears related to school satisfaction and academic performance. This brief review highlights the value of including creativity in teaching practices, drawing attention to the lack of studies and the need to develop research, both relational and quasi-experimental, on the relationship between creativity and students’ engagement in school and its effects

Avaliação dos conceitos de quantidade e intensidade de mineralização de nitrogenio para trinta solos do Rio Grande do Sul.

Visando testar aplicabilidade do modelo de mineralizacao de N, sugerido por Stanford & Smith, a alguns solos brasileiros, foram utilizados os dados de incubacao por trinta semanas obtidos por Pottker & Tedescoem trinta solos do Rio Grande do Sul. O modelo matematico utilizado parte da premissa de que apenas uma fracao do N total do solo e potencialmente mineralizavel e que esse fenomeno segue uma cinetica de primeira ordem, ou seja: dN/dt=-kN, onde N = N0 e k para os grandes grupos de solos estudados foram avaliados, sendo tecidas consideracoes sobre ambos os fatores. O modelo de mineralizacao ajustou-se perfeitamente aos solos estudados (r2 >0,99). Mesmo dentro dos grandes grupos de solos, a variacao dos valores de N0 e k e grande. A meia-vida da mineralizacao de N a 24 0c foi de 11,6 semanas. Para estimar N0 por meio de regressoes, e vantajoso trabalhar com os grandes grupos de solos isoladamente

Avaliação dos conceitos de quantidade e intensidade de mineralização de N para 30 solos do Rio Grande do Sul.

Visando testar a aplicabilidade do modelo de mineralizacao de N sugerido por Stanford & Smith (1972), a alguns solos brasileiros, foram utilizados os dados de incubacao por 30 semanas obtidos por Pottker & Tedesco (1979) para 30 solos do Rio Grande do Sul. O modelo matematico proposto pelos autores parte da premissa de que apenas uma fracao do N total do solo e potencialmente mineralizavel e que este fenomeno segue uma cinetica de 1a. ordem, ou seja: dN/dt+-kn onde N=No-Nt sendo No o nitrogenio potencialmente mineralizavel e Nt o nitrogenio mineralizado ate o tempo. A partir desta expressao sao estimados dois parametros basicos: a quantidade de N passivel de ser mineralizada (NI) e a intensidade de mineralizacao (K). As relacoes entre No e K para os grandes grupos de solos estudados foram avaliados sendo tambem tecidas consideracoes sobre estes dois fatores. O modelo de mineralizacao ajustou-se perfeitamente aos solos estudados (r2=0,99). Mesmo dentro dos grandes grupos de solos a variacao dos valores de No e K e grande .A meia vida da mineralizacao de N (t 1/2 No) a 24 oC foi de 11,6 semanas. Para estimar-se No por meio de regressoes e vantajoso trabalharc com so grandes grupos de solos isoladamente

Transthoracic echocardiography provides important long-term prognostic information in selected patients undergoing endovascular abdominal aortic repair

BACKGROUND: The value of performing transthoracic echocardiography (TTE) as part of the clinical assessment of patients awaiting endovascular repair of the abdominal aorta is little evaluated. We aimed to estimate the prognostic importance of information derived from TTE on long-term all-cause mortality in a selected group of patients undergoing endovascular aneurysm repair. METHODS AND RESULTS: This was a retrospective cohort study of 273 consecutive patients selected for endovascular aneurysm repair. All patients included in the analysis underwent TTE before their procedure. Multivariable Cox regression analysis was used to estimate the effect of TTE measures on all-cause mortality. Over a mean follow-up of 3.2±1.5 years, there were 78 deaths with a mean time to death of 1.28±1.16 years. A greater tubular ascending aorta (hazard ratio [HR] 5.6, 95% confidence interval [CI] 2.77-11.33), presence of mitral regurgitation (HR 8.13, 95% CI 4.09-12.16), lower left ventricular ejection fraction (HR 0.96, 95% CI 0.93-0.98), younger age (HR 0.97, 95% CI 0.95-0.99), and presence of diabetes mellitus (HR 1.46, 95% CI 1.24-1.89) were predictors of all-cause mortality. CONCLUSIONS: Echocardiography provides important long-term prognostic information in patients undergoing endovascular aneurysm repair. These TTE indices were more important at predicting outcome than standard conventional risk factors in this patient group. A greater tubular ascending aorta, presence of mitral regurgitation, reduced left ventricular ejection fraction, younger age, and diabetes mellitus were independently associated with long-term mortality