Magnetic properties of metallic fine particle systems

A study of the magnetic properties of metallic fine particle systems in the form of magnetic fluids has been made. The fluids were prepared utilising the organometallic decomposition route (detailed separately by N. Mason, Ph.D. thesis, Durham University 1986) and single metal systems containing Fe, Co and Ni were prepared from new precursors. The properties of the first hydrocarbon based mixed metal particle systems are also reported. For systems prepared with Fe precursors it is thought that the fine particles are not in the α-Fe phase but may be amorphous and/or consist of iron carbides. Co and Ni systems result in particles with bulk-metal like structures although Co usually forms in the f.c.c. phase. The h.c.p. is also observed. The mixed metal systems were of FeCo and Ni(_3)Fe and a tendency to form the superlattice or ordered structures was observed. In both cases Fe has been lost to the particles and this is thought to be due to the formation of volatile iron compounds during preparation and/or surfactant complexes. Narrow size distributions have been obtained in all cases with mean particle diameters in the range 4-10 nm and standard deviations of between 0.8 and 1.9. The form of the size distribution has been found to be Gaussian. A study of the anisotropy of the particles using torque and magnetisation measurements has found uniaxial anisotropy with the first anisotropy constant of the order lO(^5)Jmֿ(^3).The values observed are too large to be ascribed solely to shape anisotropy. Low temperature magnetisation measurements have revealed the existence of a paramagnetic component in the fluids. Loss of magnetisation has occurred in all systems and is thought to be due to oxidation of the metal

Food Policy Councils: Lessons Learned

As the food and financial crises bring fresh urgency to concerns over hunger, food access, public health, labor and economic development -- citizens and governments are beginning to connect these issues back to the food system as a whole. Councils are springing up across North America to "connect the dots"1 between the growing number of neighborhood food initiatives and communities forging policies for just, healthy food systems. Food Policy Councils act as both forums for food issues and platforms for coordinated action. The first Food Policy Council started in 1982 in Knoxville, Tennessee. Since then Food Policy Councils have been established at state, local and regional levels across the county. Some have remarkable success stories. Others have failed, disbanded, or spun-off into other service and non-profit organizations.What lessons can be taken from North America's three-decade experiment in formulating local food policy? Food Policy Councils: Lessons Learned is an assessment based on an extensive literature review and testimony from 48 individual interviews with the people most involved in Food Policy Councils

Piracy, File Sharing … And Legal Fig Leaves

Peer to Peer (P2P) platforms have been very effective in allowing the transmissionof large, bandwidth-intensive files (such as music and video) over the internet. Many such platformsare open source, and have been established by various operators as systems for the unauthoriseddistribution of copyright protected content.In addition to civil (and often criminal) liability faced bypersons establishing P2P platforms for the unlawful distribution of content, an end-user whodownloads copyright protected content from an unauthorised site risks civil action by the copyrightowner for breach of copyright by making an unauthorised copy of the file.The paper will look at thesignificant growth in P2P file sharing and its role as a medium for copyright piracy. The paper willexamine: how P2P file sharing facilitates internet piracy; the effect of case law; legislative changeswhich have taken place in an attempt to deter illegal distribution of copyright material through P2Pplatforms.; the effectiveness of strategies adopted by rights holders in an attempt to reduceunauthorised file sharing and ; protection measures available both for copyright owners seeking toavoid having their work illegally copied , and also third parties (such as ISPs and content hosts) whomay unknowingly become involved in the distribution of such material

The influence of a six-week, high-intensity games intervention on the pulmonary oxygen uptake kinetics in prepubertal obese and normal-weight children

Background: The pulmonary oxygen uptake ( O2) response is deleteriously influenced by obesity in pre-pubertal children, as evidenced by a slower phase II response. To date, no studies have investigated the ability of an exercise intervention to ameliorate this. Objectives: To investigate the influence of a six week, high-intensity games orientated intervention on the O2 kinetic response of pre-pubertal obese (OB) and normal-weight (NW) children during heavy intensity exercise. Methods: Thirteen NW and fifteen OB children participated in a twice-weekly exercise intervention involving repeated bouts of 6-minutes of high-intensity, games-orientated exercises followed by 2 minutes of recovery. Sixteen NW and 11 OB children served as a control group. At baseline and post-intervention, each participant completed a graded-exercise test to volitional exhaustion and constant work rate heavy intensity exercise.Results: Post intervention, OB children demonstrated a reduced phase II τ (Pre: 30±8 cf. Post: 24±7 s), MRT (Pre: 50±10 cf. Post: 38±9 s) and phase II amplitude (Pre: 1.51±0.30 cf. Post: 1.34±0.27 l∙min-1). No changes were evident in the NW children. Conclusions: The present findings demonstrate that a six-week, high-intensity intervention can have a significant positive impact on the dynamic O2 response of obese pre-pubertal children

Effect of an acute dose of omega-3 fish oil following exercise-induced muscle damage

Purpose The purpose of this double-blind, placebo-controlled study was to examine the effect of two fish oil supplements, one high in EPA (750 mg EPA, 50 mg DHA) and one low in EPA (150 mg EPA, 100 mg DHA), taken acutely as a recovery strategy following EIMD. Methods Twenty-seven physically active males (26 ± 4 year, 1.77 ± 0.07 m, 80 ± 10 kg) completed 100 plyometric drop jumps to induce muscle damage. Perceptual (perceived soreness) and functional (isokinetic muscle strength at 60° and 180° s−1, squat jump performance and countermovement jump performance) indices of EIMD were recorded before, and 1, 24, 48, 72, and 96h after the damaging protocol. Immediately after the damaging protocol, volunteers ingested either a placebo (Con), a low-EPA fish oil (Low EPA) or a high-EPA fish oil (High EPA) at a dose of 1 g per 10 kg body mass. Results A significant group main effect was observed for squat jump, with the High EPA group performing better than Con and Low EPA groups (average performance decrement, 2.1, 8.3 and 9.8%, respectively), and similar findings were observed for countermovement jump performance, (average performance decrement, 1.7, 6.8 and 6.8%, respectively, p = 0.07). Significant time, but no interaction main effects were observed for all functional and perceptual indices measured, although large effect sizes demonstrate a possible ameliorating effect of high dose of EPA fish supplementation (effect sizes ≥0.14). Conclusion This study indicates that an acute dose of high-EPA fish oil may ameliorate the functional changes following EIMD

Three Styles in the Study of Violence

This is a postprint (accepted manuscript) version of the article published in Reviews in Anthropology 37:1-19. The final version of the article can be found at http://dx.doi.org/10.1080/00938150701829525 (login required to access content). The version made available in Digital Common was supplied by the author.Accepted Manuscripttru

Genotype vs. phenotype and the rise of non-communicable diseases: the importance of lifestyle behaviors during childhood

Despite continued research and growing public awareness, the incidence of non-communicable diseases (NCD) continues to accelerate. While a person may have a genetic predisposition to certain NCDs, the rapidly changing epidemiology of NCDs points to the importance of environmental, social, and behavioural determinants of health. Specifically, three lifestyle behaviours expose children to important environmental cues and stressors: physical activity, nutritional intake, and sleep behaviour. Failure to expose children to proper gene-environment interactions, through the aforementioned lifestyle behaviours, can and will predispose children to the development of NCDs. Reengineering the environments of children can induce a paradigm shift, from a predominantly biomedical health model of treating symptomology, to a more holistic model based on encouraging appropriate behavioral decisions and optimal health

Modifiable Cardiovascular Disease Risk Factors among Indigenous Populations

Objective:. To identify modifiable cardio-metabolic and lifestyle risk factors among indigenous populations from Australia (Aboriginal Australians/Torres Strait Islanders), New Zealand (Māori), and the United States (American Indians and Alaska Natives) that contribute to cardiovascular disease (CVD). Methods:. National health surveys were identified where available. Electronic databases identified sources for filling missing data. The most relevant data were identified, organized, and synthesized. Results:. Compared to their non-indigenous counterparts, indigenous populations exhibit lower life expectancies and a greater prevalence of CVD. All indigenous populations have higher rates of obesity and diabetes, hypertension is greater for Māori and Aboriginal Australians, and high cholesterol is greater only among American Indians/Alaska Natives. In turn, all indigenous groups exhibit higher rates of smoking and dangerous alcohol behaviour as well as consuming less fruits and vegetables. Aboriginal Australians and American Indians/Alaska Natives also exhibit greater rates of sedentary behaviour. Conclusion:. Indigenous groups from Australia, New Zealand, and the United States have a lower life expectancy then their respective non-indigenous counterparts. A higher prevalence of CVD is a major driving force behind this discrepancy. A cluster of modifiable cardio-metabolic risk factors precede CVD, which, in turn, is linked to modifiable lifestyle risk factors

Hemodynamic variability and cerebrovascular control after transient cerebral ischemia

We investigated if hemodynamic variability, cerebral blood flow (CBF) regulation, and their interrelationships differ between patients with transient ischemic attack (TIA) and controls. We recorded blood pressure (BP) and bilateral middle cerebral artery flow velocity (MCAv) in a cohort of TIA patients (n = 17), and age?matched controls (n = 15). Spontaneous fluctuations in BP and MCAv were characterized by spectral power analysis, and CBF regulation was assessed by wavelet phase synchronization analysis in the very low? (0.02–0.07 Hz), low? (0.07–0.20 Hz), and high?frequency (0.20–0.40 Hz) ranges. Furthermore, cerebrovascular CO2 reactivity was assessed as a second metric of CBF regulation by inducing hypercapnia with 8% CO2 inhalation followed by hyperventilation driven hypocapnia. We found that TIA was associated with higher BP power (group effect, P < 0.05), but not MCAv power (P = 0.11). CBF regulation (assessed by wavelet phase synchronization and CO2 reactivity) was intact in patients (all P ? 0.075) across both hemispheres (all P ? 0.51). Pooled data (controls and affected hemisphere of patients) showed that BP and MCAv power were positively correlated at all frequency ranges (R2 = 0.20–0.80, all P < 0.01). Furthermore, LF phase synchronization index was a significant determinant of MCAv power (P < 0.05), while VLF and HF phase synchronization index, and TIA were not (all P ? 0.50). These results indicate that CBF stability and control is maintained in TIA patients, but BPV is markedly elevated. BPV attenuation may be an important therapeutic strategy for enhancing secondary stroke prevention in patients who suffer a TIA

Pre-Adolescent Cardio-Metabolic Associations and Correlates: PACMAC methodology and study protocol

Introduction: Although cardiovascular disease is typically associated with middle or old age, the atherosclerotic process often initiates early in childhood. The process of atherosclerosis appears to be occurring at an increasing rate, even in pre-adolescents, and has been linked to the childhood obesity epidemic. This study will investigate the relationships between obesity, lifestyle behaviours and cardiometabolic health in pre-pubescent children aged 8–10 years, and investigates whether there are differences in the correlates of cardiometabolic health between Māori and Caucasian children. Details of the methodological aspects of recruitment, inclusion/exclusion criteria, assessments, statistical analyses, dissemination of findings and anticipated impact are described. Methods and analysis Phase 1: a cross-sectional study design will be used to investigate relationships between obesity, lifestyle behaviours (nutrition, physical activity/fitness, sleep behaviour, psychosocial influences) and cardiometabolic health in a sample of 400 pre-pubescent (8–10 years old) children. Phase 2: in a subgroup (50 Caucasian, 50 Māori children), additional measurements of cardiometabolic health and lifestyle behaviours will be obtained to provide objective and detailed data. General linear models and logistic regression will be used to investigate the strongest correlate of (1) fatness; (2) physical activity; (3) nutritional behaviours and (4) cardiometabolic health. Ethics and dissemination Ethical approval will be obtained from the New Zealand Health and Disabilities Ethics Committee. The findings from this study will elucidate targets for decreasing obesity and improving cardiometabolic health among preadolescent children in New Zealand. The aim is to ensure an immediate impact by disseminating these findings in an applicable manner via popular media and traditional academic forums. Most importantly, results from the study will be disseminated to participating schools and relevant Māori health entities