Comparing Numerical Methods to Estimate Vertical Jump Height Using a Force Platform

ABSTRACT

Males (n = 29) and females (n = 34) performed vertical jumps. Jump height was estimated from force platform data using five numerical methods and compared using intraclass correlation (ρ), and linear and rank regression standard error of estimate (SEE). Take-off velocity plus center of mass height at take-off and mechanical work methods were identical (ρ = 1.000) with small linear (SEE < 0.0001 cm) and rank order (SEE = 0) error. Integrating acceleration to displacement was nearly identical (ρ > 0.999), with small linear (SEE = 0.1 cm) and rank order (SEE < 1) errors compared to the above methods. Take-off velocity (ρ = 0.517) and flight time (ρ = 0.573) estimates were less than all other methods and had large linear (SEE ≥ 2.1 cm) and rank order (SEE > 4) errors. Take-off velocity and flight time methods should be avoided due to systematic and random error.     

Characterisation of 15 century red and black pastes used for wall decoration in the Qijmas El-Eshaqi mosque (Cairo, Egypt)

The use of coloured pastes for inlaying marble and limestone wall panels is one of the ornamental techniques that were widely used during the Mamluk period in Egypt (1250–1516 AD). Red and black pastes from Qijmas El-Eshaqe mosque (1482 AD) in Cairo were studied to identify their main components. The study of the samples involved the identification of the pigments, additive materials and organic binding media. The study was performed using various analytical methods such as polarising microscopy (PLM), scanning electron microscopy equipped with energy dispersive X-ray analyser (SEM-EDX), inductively-coupled plasma (ICP-AES), X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR). These complementary analytical techniques provide precise identification of inorganic and organic substances used in the pastes. The results indicated that the red pigment is mainly obtained from red ochre containing hematite, whereas amorphous carbon (bone black and charcoal) was used to obtain the black colour. Both samples contain calcium sulphate, which was used to give some hardness to the pastes. Beeswax was used as an organic medium in both pastes. The study provides the information required for the conservation of the coloured paste ornaments.     

大学一年级英语教学浅析

本文就如何对处在大学一年级的大学生教授大学英语提出几点建议。     

Reflections on the Field: Aspirations of Learning Science and the Practical Logic of Instructional Enterprises

Over 100 years of learning and cognition research have had only modest cumulative impact on teaching, while many other practical domains such as agriculture have shown a steady growth in widely accepted, research-informed practices. Several reasons have been advanced for the painfully slow adoption of science-based instructional procedures. One important but not widely recognized obstacle is proposed here, namely, that the aims of fundamental learning and teaching research do not mesh well with the practical logic of schools. Basic learning research tends to focus on efficiency, i.e., how much can be learned from a given amount of effort or time but teaching efficiency is not a strong concern for schools. This is because they generally focus on global year-end results while the efforts required at the tactical lesson level are only loosely monitored. School administrators tend to reckon costs in terms of the number of engaged teachers and not in the difficulty of each teacher’s job. For these reasons, schools can be expected to have only nominal interests in science-informed, close management of tactical pedagogic units. Psychological work on labor saving possibilities, such as research-based instructive products, is more likely to be readily welcomed than improvements in lesson efficiency, especially in middle and high schools. Instructional enterprises in which the cost and the benefits of instruction are borne by the same agency, such as industrial training, are the most likely consumers of efficiency-related basic cognitive research.

Internal,External, and Government Political Efficacy: Effects on News Use,Discussion, and Political Participation

News use and political discussion are often studied as important factors in understanding the effects of political efficacy on participation. However, measurements of external efficacy often blur distinctions between personal ability and government responsiveness. This study establishes a measure for perceptions of competence in the institutions of democratic government—government efficacy (GE). Drawing on panel survey data from the United States, confirmatory factor analysis introduces GE as a unique construct. Political efficacy dimensions are tested for their impact on news consumption, discussion, and political participation. Results add to the extant literature revolving the role of political efficacy on news use, discussion, and participation.