Baroreflex sensitivity and developmental coordination disorder

Developmental coordination disorder (DCD) is a motor coordination disorder that is characterized by impairment of motor skills which leads to challenges with performing activities of daily living. Children with DCD have been shown to be less physically active and have increased body fatness. This is an important finding since a sedentary lifestyle and obesity are risk factors for cardiovascular disease. One indicator of cardiovascular health is baroreflex sensitivity (BRS), which is a measure of short term BP regulation that is accomplished through changes in HR. Diminished BRS is predictive of cardiovascular morbidity and mortality. The purpose of this study was to investigate BRS in 117 children aged 12 to 13 years with probable DCD (pOCO) and their matched controls with normal coordination. Following 15 minutes of supine rest, five minutes of continuous beat-by-beat blood pressure (Finapres) and RR interval were recorded (standard ECG). Spectral indices were computed using Fast Fourier Transform and transfer function analysis was used to compute BRS. High frequency and low frequency power spectral areas were set to 0.15-0.6 Hz and 0.04-0.15 Hz, respectively. BRS was compared between groups with an independent t-test and the difference was not significant. It is likely that a difference in BRS was not seen between groups since the difference in BMI between groups was small. As well, differences in BRS may not have manifested yet at this early age. However, the cardiovascular health of this population still deserves attention since differences in body composition and fitness were found between groups.

Sample preparation and heavy metal determination by atomic spectrometry /

Microwave digestions of mercury in Standards Reference Material (SRM) coal samples with nitric acid and hydrogen peroxide in quartz vessels were compared with Teflon® vessel digestion by using flow injection cold vapor atomic absorption spectrometry. Teflon® vessels gave poor reproducibiUty and tended to deliver high values, while the digestion results from quartz vessel show good agreement with certificate values and better standard deviations. Trace level elements (Ag, Ba, Cd, Cr, Co, Cu, Fe, Mg, Mn, Mo, Pb, Sn, Ti, V and Zn) in used oil and residual oil samples were determined by inductively coupled plasma-optical emission spectrometry. Different microwave digestion programs were developed for each sample and most of the results are in good agreement with certified values. The disagreement with values for Ag was due to the precipitation of Ag in sample; while Sn, V and Zn values had good recoveries from the spike test, which suggests that these certified values might need to be reconsidered. Gold, silver, copper, cadmium, cobalt, nickel and zinc were determined by continuous hydride generation inductively coupled plasma-optical emission spectrometry. The performance of two sample introduction systems: MSIS™ and gas-liquid separator were compared. Under the respective optimum conditions, MSIS^"^ showed better sensitivity and lower detection limits for Ag, Cd, Cu, Co and similar values for Au, Ni and Zn to those for the gas-liquid separator.

Interdependence in Southern Africa: an examination of the relations between Zimbabwe and South Africa

Most research on southern Africa focuses on the total dependency of the region's states--Angola, Botswana, Lesotho, Malawi, Mozambique, Swaziland, zambia and Zimbabwe--upon the dominant power, South Africa. This thesis examines the relationship between South Africa and Zimbabwe and argues that these two states are more interdependent than dependency scholars would acknowledge. Although a study of the historical period reveals that dependency theory, as defined by Raul Prebisch, Andre Gunder Frank and A. Valenzuela, is helpful for understanding the development of relations between the two states, it is unable to account for many of the characteristics of the relationship which are found in the contemporary context, especially since 1980. An examination of various economic areas of interaction, including investment, trade and transportation, as well as the political realm, indicates that each state exhibits a degree of dependence upon the other. Thus, it is possible to characterize the relationship as one of "mutual dependence," or interdependence as defined by Robert Keohane and Joseph S. Nye. Interdependence is further examined through the concepts of sensitivity and vulnerability. Sensitivity signifies the ability of a state to respond effectively to policy changes made by another state wi thin a given area of interaction without incurring large costs, while vulnerability denotes that an actor is unable to respond, or only at great cost. By applying these concepts to the relationship between Zimbabwe and South Africa, it is determined that although South Africa tends to be sensitive while Zimbabwe is generally vulnerable, the degrees to which these two states are sensi ti ve and vulnerable varies over time and issue area. As the changes wi thin South Africa start to affect relations wi th the rest of southern Africa, it wi 11 be necessary to understand the interaction between the states from an interdependency perspective if cooperation within the region wi 11 be successful. By appl ying an interdependence framework, this study aims at contributing to the understanding of relations among the countries of southern Africa in general, and between South Africa and Zimbabwe in particular.