在600～800℃低氧压下Fe－Nb合金的氧化

研究了Ｆｅ－１５Ｎｂ和Ｆｅ－３０Ｎｂ（Ｗｔ％）合金在６００～８００℃低氧压气氛中的氧化行为，实验所用的氧压处于煤的气化气氛下的氧分压范围。氧化后合金仅发生了Ｎｂ的内氧化，生成Ｎｂ２与Ｎｂ２Ｏ５，有些情况下还生成ＦｅＮｂ２Ｏ６。在６００℃时氧化速度很低，但在７００～８００℃时则颇高。这些合金内氧化的重要特征之一，是其内氧化物的分布几乎完全与合金中的高含Ｎｂ相一致。此外，合金氧化后均不出现外氧化层。这些可能都是由于Ｎｂ在Ｆｅ中溶解度很低且合金呈两相组织所致。     

Is autonomic control of the heart rate at rest altered by detraining? A study of heart rate variability in professional soccer players after the pretraining period and after the preparatory period for competitions

The aim of this study was to assess the influence of detraining and training on the autonomic control of heart rate (HR), using time and frequency (spectral analysis) domain components of heart rate variability. Sixteen professional football players (26.7 +/- 3.8 years; 74.9 +/- 4.1 kg; 177 +/- 6.3 cm) were analysed at the end of a 1 month holiday (detraining) and after a 6 week training period (training). HR was recorded over 15 minutes with Holter equipment. The athletes rested in a supine position, in a quiet place and all test were performed between 8 and 10 AM. The subjects were requested to refrain from meals or caffeine for 12 hours before testing. In spite of the high intensity of the training period, there was no significant change in results from detraining condition to training condition. These results can have two possible explanations: (i) the high level of cardiovascular capacity in the detraining trial originated by the recreative physical activity that the players underwent during their holidays, and/or (ii) the training period was not long enough to promote any relevant effect on the autonomic control of HR.     

A recurrent neural network architecture to model physical activity energy expenditure in older people

Data Mining and Knowledge Discovery - Through the quantification of physical activity energy expenditure (PAEE), health care monitoring has the potential to stimulate vital and healthy ageing,...     

Evaluating the antioxidant capacity of wines: a laccase-based biosensor approach

Polyphenolic compounds present in wine have a high antioxidant capacity providing a protective effect on human health. There is a worldwide agreement on this assertion. However, there is no agreement on the method of assessing the antioxidant capacity of wines. The purpose of this study was to emphasize the ability of the laccase-based biosensor developed by our group to evaluate the antioxidant capacity of several types of wine in relation to their polyphenolic content. The values of total antioxidant activity of the investigated wine samples were well correlated with the corresponding bioelectrochemical polyphenol-estimated values, the correlation coefficient obtained being r = 0.9795 (p < 0.05). The linear relationship between total antioxidant activity and bioelectrochemical polyphenol index determined by laccase-based biosensor enabled the calculation of the TEAC (Trolox Equivalent Antioxidant Capacity) of a wine from its bioelectrochemical polyphenol index.     

Geometry, the Measure of the World

This study considers the relationship between the approach to urban planning in Portugal up to the eighteenth century, and the effective process of urbanisation, from both a theoretical and practical perspective. Portuguese urban layout does not develop as a set of random shapes but rather arises from structured thinking by “urban makers” who are firmly grounded in the subject of geometry. Being able to measure the universe and codify it in drawings was one of the major scientific accomplishments of the age of Portuguese discoveries in the sixteenth century and the acquisition of such knowledge demanded a unique ability for abstraction which could not have simply emerged out of nothing. Portugal’s investment in the training of skilled professionals is made evident in treatises, manuals, dissertations, and cartography and iconography works. The interpretation of the ideas of Order and Space in urban design evolved through history in parallel with the evolution of philosophical and scientific thought. In fact, urban space is associated the search of the laws of the nature and the intelligibility of the cosmos.