Ocean acidification in the aftermath of the Marinoan glaciation

Boron isotope patterns preserved in cap carbonates deposited in the aftermath of the younger Cryogenian (Marinoan, ca. 635 Ma) glaciation confirm a temporary ocean acidification event on the continental margin of the southern Congo craton, Namibia. To test the significance of this acidification event and reconstruct Earth’s global seawater pH states at the Cryogenian-Ediacaran transition, we present a new boron isotope data set recorded in cap carbonates deposited on the Yangtze Platform in south China and on the Karatau microcontinent in Kazakhstan. Our compiled δ11B data reveal similar ocean pH patterns for all investigated cratons and confirm the presence of a global and synchronous ocean acidification event during the Marinoan deglacial period, compatible with elevated postglacial pCO2 concentrations. Differences in the details of the ocean acidification event point to regional distinctions in the buffering capacity of Ediacaran seawater

Eating Behavior of Obese and Nonobese Retarded Adults

An obese group and a nonobese group of moderately mentally retarded adults were identified through use of body weight and tricep skinfold thickness measures. Subjects were observed individually in a sheltered workshop cafeteria during their normal lunch period. A variety of eating behavior measureswere obtained. Results indicated that the obese retarded subjects did not differ from their nonobese peers in eating rate, total meal time, or caloric intake. Large variability was observed in the measures for both groups. Implications of these data for behavioral treatments of obesity and the need for alternative explanations of an obese condition were discussed

Effects of Vascular Nitric Oxide Bioactivity and Vascular Ageing on Arterial Blood Pressure and Flow Waveforms

Analysis of blood pressure and flow waveforms may lead to improved diagnosis of arterial dysfunction and disease. This thesis describes experiments to investigate the characteristic alteration of peripheral waveforms produced by stimulated release of vascular nitric oxide (an effect that is attenuated by endothelial dysfunction) and the changes that occur with age. In vivo experiments were conducted in anaesthetised rabbits and in vitro experiments employed a polyurethane model of the human aorta and its principal branches. Blood pressure, blood flow, pulse wave velocities and vessel diameter were recorded in the rabbit abdominal aorta. Equivalent recordings were obtained from the model aorta. Data were analysed in the time domain using wave intensity analysis after separation of reservoir (Windkessel) pressure and wave pressure. Effects of acetylcholine (Ach) and NG-nitro-L-arginine methyl ester (L-NAME) were investigated in vivo. Ach (which promotes endothelial production of nitric oxide) increased wave reflection, whilst L-NAME (which inhibits nitric oxide production) decreased it. These trends were opposite to the expected ones, and do not account for the established effects of nitric oxide on peripheral arterial waveforms. Further work is required to investigate these contradictions. Arterial stiffening in immature and mature rabbits was attempted by supplementing their diet with fructose. Fructose is known to form advanced glycation end-products in arterial walls and hence to stiffen arteries. Unexpectedly, fructose did not affect haemodynamic function. However, immature control rabbits had markedly reduced aortic wave reflection compared to mature control rabbits, indicating that the former have arterial impedances that are better matched for incident wave propagation. Wrapping the model aorta in Clingfilm was used to simulate age- or drug-induced stiffening of the aorta in vivo. Increased pulse pressure was observed, resembling the isolated systolic hypertension prevalent in aged populations. The model has potential for modelling haemodynamic function in health and disease

Obesity of Mentally Retarded Individuals: Prevalence, Characteristics, and Intervention

Research on the prevalence, characteristics, and treatment of obesity of mentally retarded individuals within the context of research findings with the obese nonretarded population was selectively reviewed. According to the available literature, obesity is a prevalent problem in the retarded population, and there is a greater incidence among females than males. The literature also suggests that obese retarded subjects as a group can be distinguished from their nonobese peers by their physical condition, but not by their eating style or personality characteristics. Behavioral self-control strategies have been found to be effective in producing weight loss in obese retarded children and adults. Further research is needed to reduce the high interindividual variability observed in treatment outcome studies and to address problems of long-term maintenance of weight loss

Injury in Ireland

Injury mortality is the fourth commonest cause of death in Ireland. The treatment of injuries has a major impact on our hospitals and on our budget for health. Long term disability following accidents is a serious problem. The aim of this report is to examine the impact of accidents and injuries on the Irish population by analysing routine mortality and morbidity data, and to identify in turn those areas where preventive measures could have an impact. In Section One the literature review details the advantages and disadvantages of each type of routine data source used in this report. The interpretation of data should take account of the constraints of the available data collected. The usefulness of routine data collection is highlighted, while identifying areas for improvement. In Section Two the methodology employed in the study is detailed. In Section Three data on hospital admissions over a five-year period 1993-1997 are presented. An overview of injury admissions is presented, followed by further analysis of injury data by both cause and by age group. In Section Four data on all accident-related deaths over a 17-year period, 1980-1996, are presented, with overall mortality data and mortality data by age group and by major causes of injury death detailed. In Section Five comparisons are made between the eight health board regions for rates of admissions and deaths due to injury. In presenting the data we use a matrix format devised and recommended by the International Collaborative Effort on Injury Statistics to display injury simultaneously by cause and intent. The use of a common format will also facilitate regional and international comparisons. In Section Six the priority recommendations for injury prevention are outlined. The key findings are then discussed and further recommendations are presented with the aim of injury prevention, reduction of disability and improvement in injury surveillance

Cooling Fermions in an Optical Lattice by Adiabatic Demagnetization

The Fermi-Hubbard model describes ultracold fermions in an optical lattice and exhibits antiferromagnetic long-ranged order below the N\'{e}el temperature. However, reaching this temperature in the lab has remained an elusive goal. In other atomic systems, such as trapped ions, low temperatures have been successfully obtained by adiabatic demagnetization, in which a strong effective magnetic field is applied to a spin-polarized system, and the magnetic field is adiabatically reduced to zero. Unfortunately, applying this approach to the Fermi-Hubbard model encounters a fundamental obstacle: the $SU(2)$ symmetry introduces many level crossings that prevent the system from reaching the ground state, even in principle. However, by breaking the $SU(2)$ symmetry with a spin-dependent tunneling, we show that adiabatic demagnetization can achieve low temperature states. Using density matrix renormalization group (DMRG) calculations in one dimension, we numerically find that demagnetization protocols successfully reach low temperature states of a spin-anisotropic Hubbard model, and we discuss how to optimize this protocol for experimental viability. By subsequently ramping spin-dependent tunnelings to spin-independent tunnelings, we expect that our protocol can be employed to produce low-temperature states of the Fermi-Hubbard Model.Comment: References adde

Appropriate Classification of Obesity in Mentally Retarded Adults

Triceps skinfold thickness and body weight measures were obtained for 44 female and 40 male mentally retarded adults participating in a sheltered workshop setting. Subiects\u27 relative weights and skinfold thicknesses were found to correlate reasonably well for females and males, rs = .88 and .59, respectively. Use of only height and weight tables for determining the presence of obesity, however, resulted in 22.5 percent of the males and 13 .7 percent of the females being misclassified as nonobese. The distinction between overweight and obesity was discussed. Clinical/research implications of the findings were delineated

Predictors of refusal to participate: a longitudinal health survey of the elderly in Australia

BACKGROUND: The loss of participants in longitudinal studies due to non-contact, refusal or death can introduce bias into the results of such studies. The study described here examines reasons for refusal over three waves of a survey of persons aged ≥ 70 years. METHODS: In a longitudinal study involving three waves, participants were compared to those who refused to participate but allowed an informant to be interviewed and to those who refused any participation. RESULTS: At Wave 1 both groups of Wave 2 non-participants had reported lower occupational status and fewer years of education, had achieved lower verbal IQ scores and cognitive performance scores and experienced some distress from the interview. Those with an informant interview only were in poorer physical health than those who participated and those who refused. Depression and anxiety symptoms were not associated with non-participation. Multivariate analyses found that verbal IQ and cognitive impairment predicted refusal. Results were very similar for refusers at both Waves 2 and 3. CONCLUSIONS: Longitudinal studies of the elderly may over estimate cognitive performance because of the greater refusal rate of those with poorer performance. However, there is no evidence of bias with respect to anxiety or depression