Percepções da eficiência de sistemas de apresentação de conteúdos didáticos: uma comparação entre estudantes de ensino a distância e estudantes presenciais

Este estudo compara as percepções de estudantes sobre a eficiência do ensino por vários sistemas de apresentação de conteúdos didáticos entre estudantes de ensino à distância e estudantes presenciais. As comparações foram realizadas em três níveis: (a) eficiência geral dos sistemas de apresentação de conteúdos didáticos; (b) eficiência dos sistemas de apresentação de conteúdos didáticos sob aspectos individuais; e (c) eficiência dos sistemas de apresentação de conteúdos didáticos em cada nível. Os resultados deste estudo mostraram que os estudantes de ensino à distância perceberam a eficiência dos sistemas de apresentação de conteúdos didáticos mais positivamente que os estudantes presenciais. Embora, nenhuma diferença estatística significativa foi encontrada nas percepções da eficiência dos sistemas de apresentação de conteúdos didáticos em geral e sob aspectos individuais, algumas diferenças significativas foram encontradas quando essas percepções foram comparadas em cada nível. Além disso, resultados deste estudo sugerem que um sistema de apresentação de conteúdos didáticos híbrido pode obter melhor eficiência quando várias tarefas de ensino e aprendizagem estão presentes nesse sistema

Endovascular Thrombectomy for Mild Strokes: How Low Should We Go? A Multicenter Cohort Study

Background and Purpose:Endovascular thrombectomy (EVT) is effective for acute ischemic stroke with large vessel occlusion (LVO) and NIHSS ≥6. However, EVT benefit for mild deficits LVOs (NIHSS Methods: A retrospective cohort of patients with anterior circulation LVO and NIHSSoutcome; mRS=0–2 was the secondary. Symptomatic intracerebral hemorrhage (sICH) was the safety outcome. Clinical outcomes were compared through a multivariable logistic regression after adjusting for age, presentation NIHSS, time-last-seen-normal-to-presentation, center, IV-alteplase, ASPECTS, and thrombus location. We then performed propensity score matching as a sensitivity analysis. Results were also stratified by thrombus location. Results: 214 patients (EVT-124, medical management-90) were included from 8 US and Spain centers between January/2012 and March/2017. The groups were similar in age, ASPECTS, IValteplase rate and time-last-seen-normal-to-presentation. There was no difference in mRS=0–1 between EVT and medical management (55.7% versus 54.4%, respectively, aOR=1.3, 95%CI=0.64–2.64, p=0.47). Similar results were seen for mRS=0–2 (63.3% EVT versus 67.8% medical management, aOR=0.9, 95%CI=0.43–1.88, p=0.77). In a propensity matching analysis, there was no treatment effect in 62 matched pairs (53.5%EVT, 48.4% medical management; OR=1.17, 95%CI=0.54–2.52, p=0.69). There was no statistically significant difference when stratified by any thrombus location; M1 approached significance (p=0.07). sICH rates were higher with thrombectomy (5.8% EVT versus 0% medical management, p=0.02). Conclusions: Our retrospective multicenter cohort study showed no improvement in excellent and independent functional outcomes in mild strokes (NIHS

International external validation of a stratification tool to identify branch-duct intraductal papillary mucinous neoplasms at lowest risk of progression

BACKGROUND: Identifying branch‐duct intraductal papillary mucinous neoplasms (BD‐IPMNs) at lowest risk of progression may allow for a reduced intensity of surveillance. OBJECTIVE: We aimed to externally validate the previously developed Dutch‐American Risk stratification Tool (DART‐1; https://rtools.mayo.edu/DART/), which identifies cysts at low risk of developing worrisome features (WFs) or high‐risk stigmata (HRS). METHODS: Three prospective cohorts of individuals under surveillance for BD‐IPMNs were combined, independent from the original development cohort. We assessed the performance (discrimination and calibration) of DART‐1, a multivariable Cox‐proportional logistic regression model with five predictors for the development of WFs or HRS. RESULTS: Of 832 individuals (mean age 77 years, SD 11.5) under surveillance for a median of 40 months (IQR 44), 163 (20%) developed WFs or HRS. DART‐1's discriminative ability (C‐statistic 0.68) was similar to that in the development cohort (0.64–0.72) and showed moderate calibration. DART‐1 adequately estimated the risk for patients in the middle risk quintile, and slightly underestimated it in the lowest quintiles. Their range of predicted versus observed 3‐year risk was 0%–0% versus 0%–3.7% for Q1; 0.3%–0.4% versus 3%–11% for Q2; and 2.6%–3% versus 2.4%–9.8% for Q3. The development of WFs or HRS was associated with pancreatic cancer (p < 0.001). Vice versa, in absence of WFs or HRS, the risk of malignancy was low (0.3%). CONCLUSIONS: The performance of DART‐1 to predict the development of WFs or HRS in BD‐IPMN was validated in an external international cohort, with a discriminative ability equal as in the development cohort. Risk estimations were most accurate for patients with BD‐IPMNs in the middle risk quintile and slightly underestimated in the lowest quintiles

Synthesis and antitumor activity of bis-platinum complexes varying in the nature of the bridging diamine linker group.

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/29214/1/0000268.pd

The challenges of ethical research with children

As especificidades da pesquisa com crianças têm ganhado visibilidade nas produções acadêmicas em diversas áreas de conhecimento, com destaque para a Sociologia da Infância, principalmente a partir dos “novos estudos sobre a infância” os quais emergiram ao final da década de 1980. Essa visibilidade acontece devida a questões como: a discussão sobre as imagens da infância, construídas socio-historicamente; o reconhecimento da condição das crianças enquanto atores sociais, portanto, seres competentes, que atribuem significações a suas experiências e contextos; e o reconhecimento das crianças enquanto sujeitos de direitos, reconhecimento este pautado pela Doutrina da Proteção Integral. Permeadas por essas questões, as pesquisas com crianças agregam a questão da Ética nas atividades desenvolvidas na relação pesquisador-criança. No contexto dessa discussão, este trabalho propõe refletir sobre essas questões e os cuidados éticos nesse tipo de pesquisa, considerando a condição da criança enquanto sujeito de direitos. Foi realizado um recorte da produção acadêmica representativa na área da Sociologia da Infância nas duas últimas décadas, identificando quais aspectos aparecem nas preocupações dos autores, quais abordagens norteiam a discussão desses aspectos e, principalmente, que concepção de infância está presente nessa produção.The specificities of research with children have gained visibility in scientific publications in various areas of knowledge, especially in Sociology of Childhood and the “new studies of childhood”, which emerged at the end of the 1980s. This fact is due to discussions about childhood from a socio-historical perspective; the recognition of children as social actors and therefore able to give meaning to their experiences and contexts; and the recognition of children as individuals entitled to rights, according to the Doutrina da Proteção Integral (Full Protection Doctrine). Therefore, research ethics is an essential element of good research governance, especially in terms of activities related to the relationship between the researcher and child. Accordingly, the objective of this study is to examine and explore these issues, considering the child as an individual entitled to rights. A literature review of articles published in the last two decades in the area of Sociology of Childhood was conducted to identify the main issues and topics addressed, the approaches that guided the discussions and, especially, to identify the conception of childhood present in these studies.CIEC - Centro de Investigação em Estudos da Criança, IE, UMinho (UI 317 da FCT), Portuga

Applications of electrified dust and dust devil electrodynamics to Martian atmospheric electricity

Atmospheric transport and suspension of dust frequently brings electrification, which may be substantial. Electric fields of 10 kVm-1 to 100 kVm-1 have been observed at the surface beneath suspended dust in the terrestrial atmosphere, and some electrification has been observed to persist in dust at levels to 5 km, as well as in volcanic plumes. The interaction between individual particles which causes the electrification is incompletely understood, and multiple processes are thought to be acting. A variation in particle charge with particle size, and the effect of gravitational separation explains to, some extent, the charge structures observed in terrestrial dust storms. More extensive flow-based modelling demonstrates that bulk electric fields in excess of 10 kV m-1 can be obtained rapidly (in less than 10 s) from rotating dust systems (dust devils) and that terrestrial breakdown fields can be obtained. Modelled profiles of electrical conductivity in the Martian atmosphere suggest the possibility of dust electrification, and dust devils have been suggested as a mechanism of charge separation able to maintain current flow between one region of the atmosphere and another, through a global circuit. Fundamental new understanding of Martian atmospheric electricity will result from the ExoMars mission, which carries the DREAMS (Dust characterization, Risk Assessment, and Environment Analyser on the Martian Surface)-MicroARES (Atmospheric Radiation and Electricity Sensor) instrumentation to Mars in 2016 for the first in situ measurements

Buying to Sell: A Theory of Buyouts

Private equity owned firms have more leverage, more intense compensation contracts, and higher productivity than comparable firms. We develop a theory of buyouts in oligopolistic markets that explains these facts. Private equity firms are more aggressive in inducing restructuring compared to incumbents since they maximize a trade sale price. The equilibrium trade sale price increases in restructuring not only by increasing the profit of the acquirer, but also by decreasing the profits of non-acquiring firms. Predictions on the exit mode and on when private equity firms can outbid incumbents in the market for corporate control are also derived