Diseño, implementación y análisis de una secuencia de enseñanza de la distribución normal en un curso universitario

Este trabajo se centra en la enseñanza y aprendizaje de la distribución normal en un curso introductorio de estadística en la Universidad, y se fundamenta en un marco teórico que plantea el significado institucional y personal de los objetos matemáticos. En particular, se describe el diseño de una experiencia de enseñanza de la distribución normal apoyada en el uso del ordenador y se analizan los avances, dificultades y errores que presentan los alumnos durante el desarrollo de dicha experiencia. En el estudio se presta especial atención a todo lo que implica en la enseñanza de estadística la introducción del computador. Pretendemos aportar información válida sobre la enseñanza/aprendizaje de la estadística en cursos universitarios, que pueda ser completada y ampliada en futuras investigaciones.

Assessing the suitability of ship design for human factors issues associated with evacuation and normal operations

Evaluating ship layout for human factors (HF) issues using simulation software such as maritimeEXODUS can be a long and complex process. The analysis requires the identification of relevant evaluation scenarios; encompassing evacuation and normal operations; the development of appropriate measures which can be used to gauge the performance of crew and vessel and finally; the interpretation of considerable simulation data. In this paper we present a systematic and transparent methodology for assessing the HF performance of ship design which is both discriminating and diagnostic. The methodology is demonstrated using two variants of a hypothetical naval ship.

A systematic review of the effect of dietary exposure that could be achieved through normal dietary intake on learning and performance of school-aged children of relevance to UK schools

The aim of the present review was to perform a systematic in-depth review of the best evidence from controlled trial studies that have investigated the effects of nutrition, diet and dietary change on learning, education and performance in school-aged children (4-18 years) from the UK and other developed countries. The twenty-nine studies identified for the review examined the effects of breakfast consumption, sugar intake, fish oil and vitamin supplementation and 'good diets'. In summary, the studies included in the present review suggest there is insufficient evidence to identify any effect of nutrition, diet and dietary change on learning, education or performance of school-aged children from the developed world. However, there is emerging evidence for the effects of certain fatty acids which appear to be a function of dose and time. Further research is required in settings of relevance to the UK and must be of high quality, representative of all populations, undertaken for longer durations and use universal validated measures of educational attainment. However, challenges in terms of interpreting the results of such studies within the context of factors such as family and community context, poverty, disease and the rate of individual maturation and neurodevelopment will remain. Whilst the importance of diet in educational attainment remains under investigation, the evidence for promotion of lower-fat, -salt and -sugar diets, high in fruits, vegetables and complex carbohydrates, as well as promotion of physical activity remains unequivocal in terms of health outcomes for all schoolchildren.

Abnormal endothelial tight junctions in active lesions and normal-appearing white matter in multiple sclerosis

Blood-brain barrier (BBB) breakdown, demonstrable in vivo by enhanced MRI is characteristic of new and expanding inflammatory lesions in relapsing remitting and chronic progressive multiple sclerosis (MS). Subtle leakage may also occur in primary progressive MS. However, the anatomical route(s) of BBB leakage have not been demonstrated. We investigated the possible involvement of interendothelial tight junctions (TJ) by examining the expression of TJ proteins (occludin and ZO-1 ) in blood vessels in active MS lesions from 8 cases of MS and in normal-appearing white (NAWM) matter from 6 cases. Blood vessels (10-50 per frozen section) were scanned using confocal laser scanning microscopy to acquire datasets for analysis. TJ abnormalities manifested as beading, interruption, absence or diffuse cytoplasmic localization of fluorescence, or separation of junctions (putative opening) were frequent (affecting 40% of vessels) in oil red-O-positive active plaques but less frequent in NAWM (15%), and in normal (

Upregulation of osteopontin and alpha B crystallin in the normal-appearing white matter of multiple sclerosis: an immunohistochemical study utilizing tissue microarrays

Tissue microarrays assembled from control and multiple sclerosis (MS) brain tissue have been used to assess the expression patterns and cellular distribution of two antigens, the proinflammatory cytokine osteopontin and the inducible heat shock protein alpha B -crystallin, which have previously been implicated in MS pathogenesis. Tissue cores were taken from paraffin-embedded donor blocks containing chronic active or chronic inactive plaques and normal-appearing white matter (NAWM) in seven MS cases, and white matter (WM) in five control cases. Expression patterns of both proteins were assessed against myelin density and microglial activation in the different tissue categories. Both proteins showed increased expression in all categories of MS tissue compared with control WM. The results indicate progressive up-regulation of expression of osteopontin with increased plaque activity, while elevation of alpha B-crystallin expression in MS tissue was independent of demyelination. In MS NAWM a significant correlation was observed between high levels of expression of osteopontin and alpha B -crystallin. Osteopontin expression was predominantly confined to astrocytes throughout MS tissues. alpha B -crystallin was expressed on astrocytes, oligodendrocytes and occasionally on demyelinated axons. Taken together, these data indicate a wider distribution of osteopontin and alpha B -crystallin in MS tissues than previously described and support their proposed role in MS pathogenesis.

A comparison between randomly alternating imaging, normal laparoscopic imaging, and virtual reality training in laparoscopic psychomotor skill acquisition

Objectives: To evaluate virtual reality as a laparoscopic training device in helping surgeons to automate to the “fulcrum effect” by comparing it to time-matched training programs using randomly alternating images (ie, y-axis inverted and normal laparoscopic) and normal laparoscopic viewing conditions.

Methods: Twenty-four participants (16 females and 8 males), were randomly assigned to minimally invasive surgery virtual reality (MIST VR), randomly alternating (between y-axis inverted and normal laparoscopic images), and normal laparoscopic imaging condition. Participants were requested to perform a 2-minute laparoscopic cutting task before and after training.

Results: In the test trial participants who trained on the MIST VR performed significantly better than those in the normal laparoscopic and randomly alternating imaging conditions.

Conclusion: The results show that virtual reality training may provide faster skill acquisition with particular reference to automation of the fulcrum effect. MIST VR provides a new way of training laparoscopic psychomotor surgical skills.

Normal levels of prepulse inhibition in the euthymic phase of bipolar disorder.

BACKGROUND:Deficits in prepulse inhibition (PPI) of the acoustic startle response have been suggested as a potentially useful endophenotype for schizophrenia spectrum disorders and may explain certain symptoms and cognitive deficits observed in the psychoses. PPI deficits have also been found in mania, but it remains to be confirmed whether this dysfunction is present in the euthymic phase of bipolar disorder.METHOD: Twenty-three adult patients with DSM-IV bipolar disorder were compared to 20 controls on tests of acoustic startle reactivity and PPI of the startle response. Sociodemographic and treatment variables were recorded and symptom scores assessed using the Hamilton Depression Inventory and the Young Mania Rating Scale.RESULTS:Overall, the patient and control groups demonstrated similar levels of startle reactivity and PPI, although there was a trend for the inter-stimulus interval to differentially affect levels of PPI in the two groups.CONCLUSIONS: In contrast to bipolar patients experiencing a manic episode, general levels of PPI were normal in this euthymic sample. Further studies are required to confirm this finding and to determine the mechanisms by which this potential disruption/normalization occurs. It is suggested that an examination of PPI in a high-risk group is required to fully discount dysfunctional PPI as a potentially useful endophenotype for bipolar disorder.