O comportamento do aluno em um curso a distância dentro do ambiente Moodle: contrapontos entre a ótica inicial e seu uso atual.

O objetivo deste trabalho é analisar as dificuldades apresentadas pelos alunos de cursos em EaD. Para tanto, utilizou-se dados extraídos de um questionário de inscrição para um curso on-line, em que era solicitado aos alunos que listassem seus maiores problemas com os cursos que já haviam feito. Puderam ser identificadas seis categorias de problemas com: AVA, tutor, técnicos, de organização, de colaboração e de conteúdo

A disposable continuum endoscope using piston-driven parallel bellow actuator

This paper presents a novel low cost disposable continuum endoscope based on a piston-driven parallel bellow actuator design. The parallel bellow actuator achieves motion by being pressurized via displacement-controlled pistons. The displacements are generated by rack-and-pinion mechanisms using inexpensive stepper motors. The design concept provides a potential alternative solution to upper gastrointestinal (UGI) diagnosis. The modularity and the use of inexpensive components allow for low fabrication costs and disposability. The use of robotic assistance could facilitate the development of an easier interface for the gastroenterologists, avoiding the nonintuitive manipulation mapping of the traditional UGI endoscopes. We adapt existing kinematic solutions of multi-backbone continuum robots to model continuum parallel bellow actuators. An actuation compensation strategy is presented and validated to address the pneumatic compressibility through the transmission lines. The design concept was prototyped and tested with a custom control platform. The experimental validation shows that the actuation compensation was demonstrated to significantly improve orientation control of the endoscope end-effector. This paper shows the feasibility of the proposed design and lays the foundation toward clinical scenarios

Influence of cellulose nanofibrils on the rheology, microstructure and strength of alkali activated ground granulated blast-furnace slag: a comparison with ordinary Portland cement

This paper reports on the effect of cellulose nanofibrils (CNFs) on the fresh-state properties of alkali activated ground granulated blast-furnace slag (GGBS). Surface functionalized (oxidized) CNFs were added to alkali activated GGBS water suspensions (hydraulic pastes). The rheological behaviour of the pastes was compared with OPC and interpreted based on the CNF-mineral surface interaction, and on the CNF-water interaction and swelling. The water dispersion of CNFs with different surface functionalization degrees resulted in gels of different viscosity and yield stress, due to their different hydrophilicity and water adsorption properties. On increasing the CNFs surface oxidation degree, the viscosity of the CNF water dispersion decreases and the CNF water adsorption increases, while the viscosity of fresh pastes increases because of the reduced amount of available mixing water. In the hardened state, the hydraulic pastes show differences in mechanical strength related to the type and the amount of CNF influencing the porosity of the matrix as evidenced by the microstructural investigation performed by X-ray microtomography. The presence of higher amounts of CNFs induces the formation of porous agglomerates that may act as stress concentrators due to the swelling ability of nanofibrils

Influence of Ageing Time and Method on Beef Quality and Safety

The effectiveness of dry ageing with regard to retaining meat quality is still subject to debate. At 4 d post mortem, samples of boneless strip loins were excised from young Charolais carcasses and then stored for a further 26 d in a cooler, either vacuum-packaged (VP) or dried-aged (DA). Loin samples were also dissected 7 d post mortem as a control treatment (CT). Chemical, instrumental and microbiological data (n = 18) were determined in longissimus dorsi and underwent ANOVA to estimate the differences in the ageing fixed factor split into two orthogonal contrasts: control vs. aged and VP vs. DA. Ageing loss (both surface dehydration and water purge) was greater in DA compared to VP samples, resulting in the lowest moisture content and highest crude protein and fat percentage in DA loins. The ageing method did not affect meat surface colour, except for redness, which had the lowest value in DA samples. Meat tenderness improved a similar amount following both VP and DA ageing treatments. Compared to the control, prolonged ageing raised both the peroxide value and the total microbial count, especially in DA samples, though both remained within the recommended limits. In summation, both ageing methods improved beef meat tenderisation, preserving its shelf life

On the appearance of Eisenstein series through degeneration

Let $\Gamma$ be a Fuchsian group of the first kind acting on the hyperbolic upper half plane $\mathbb H$, and let $M = \Gamma \backslash \mathbb H$ be the associated finite volume hyperbolic Riemann surface. If $\gamma$ is parabolic, there is an associated (parabolic) Eisenstein series, which, by now, is a classical part of mathematical literature. If $\gamma$ is hyperbolic, then, following ideas due to Kudla-Millson, there is a corresponding hyperbolic Eisenstein series. In this article, we study the limiting behavior of parabolic and hyperbolic Eisenstein series on a degenerating family of finite volume hyperbolic Riemann surfaces. In particular, we prove the following result. If $\gamma \in \Gamma$ corresponds to a degenerating hyperbolic element, then a multiple of the associated hyperbolic Eisenstein series converges to parabolic Eisenstein series on the limit surface.Comment: 15 pages, 2 figures. This paper has been accepted for publication in Commentarii Mathematici Helvetic

RTN in GexSe1-x OTS Selector Devices

Random telegraph noise (RTN) signals in GexSe1-x ovonic threshold switching (OTS) selector have been analyzed in this work, both before and after the first-fire (FF) operation and at on- and off-states. It is observed that RTN appears after the FF, and its absolute amplitude at the off-state is small and negligible in comparison with the RTN signals in RRAM devices. At the on-state, large RTN signals are observed, which can either partially or fully block the conduction path, supporting that a conductive filament is formed or activated by FF and then modulated during switching. Statistical analysis reveals that the relative RTN amplitude at on-state in GexSe1-x OTS selector is smaller than or equivalent to those in RRAM devices

A Corte Interamericana de Direitos Humanos e a judicialização internacional da política doméstica

This paper explores specific features in the IHR Court that demonstrate international judicialization of domestic politics. We map no repetition measures in the Court’s rulings against South American States through qualitative research design, along with descriptive statistics. Then, we evaluate the difficulties to comply with these measures, as well as the possible impacts regarding States policies.O artigo explora elementos das sentenças da Corte IDH que evidenciem processos de judicialização internacional de políticas domésticas.  Por meio de um desenho de pesquisa qualitativo, associado a estatísticas descritivas, mapeamos medidas de não repetição em sentenças da Corte contra Estados Sul-Americanos, avaliamos dificuldades de cumprimento dessas medidas e apresentamos possíveis impactos nas políticas estatais

Dual-Continuum Design Approach for Intuitive and Low-Cost Upper Gastrointestinal Endoscopy

Objective: This paper introduces a methodology to design intuitive, low-cost, and portable devices for visual inspection of the upper gastrointestinal tract. Methods: The proposed approach mechanically couples a multi-backbone continuum structure, as the user interface, and a parallel bellows actuator, as the endoscopic tip. Analytical modeling techniques derived from continuum robotics were adopted to describe the endoscopic tip motion from user input, accounting for variations in component size and pneumatic compressibility. The modeling framework was used to improve intuitiveness of user-to-task mapping. This was assessed against a 1:1 target, while ease-of-use was validated using landmark identification tasks performed in a stomach simulator by one expert and ten non-expert users; benchmarked against conventional flexible endoscopy. Pre-clinical validation consisted of comparative trials in in-vivo porcine and human cadaver models. Results: Target mapping was achieved with an average error of $5^\circ$ in bending angle. Simulated endoscopies were performed by an expert user successfully, within a time comparable to conventional endoscopy ( $<$ 1 min difference). Non-experts using the proposed device achieved visualization of the stomach in a shorter time (9 s faster on average) than with a conventional endoscope. The estimated cost is $<$ 10 USD and $<$ 30 USD for disposable and reusable parts, respectively. Significance and Conclusions: Flexible endoscopes are complex and expensive devices, actuated via non-intuitive cable-driven mechanisms. They frequently break, requiring costly repair, and necessitate a dedicated reprocessing facility to prevent cross contamination. The proposed solution is portable, inexpensive, and easy to use, thus lending itself to disposable use by personnel without formal training in flexible endoscopy

Análise econômica de integração lavoura-pecuária no pampa gaúcho sob condições de risco.

Resumo.Fernando Flores Cardoso, Daniel Portella Montardo, José Carlos Ferrugem Moraes, Marcos Flávio Silva Borba, Sandro da Silva Camargo, editores técnicos