2,276 research outputs found
On differential uniformity of maps that may hide an algebraic trapdoor
We investigate some differential properties for permutations in the affine
group, of a vector space V over the binary field, with respect to a new group
operation , inducing an alternative vector space structure on .Comment: arXiv admin note: text overlap with arXiv:1411.768
Time trends in reported prevalence of kidney stones in the United States: 1976â199411.See Editorial by Goldfarb, p. 1951.
Time trends in reported prevalence of kidney stones in the United States: 1976â1994.BackgroundA body of evidence establishes that the occurrence of kidney stone disease has increased in some communities of industrialized countries. Information on recent temporal trends in the United States is lacking and population-based data on epidemiologic patterns are limited.Study objective was to determine whether kidney stone disease prevalence increased in the United States over a 20-year period and the influence of region, race/ethnicity, and gender on stone disease risk.MethodsWe measured the prevalence of kidney stone disease history from the United States National Health and Nutrition Examination Survey (II and III), population-based, cross-sectional studies, involving 15,364 adult United States residents in 1976 to 1980 and 16,115 adult United States residents in 1988 to 1994.ResultsDisease prevalence among 20- to 74-year-old United States residents was greater in 1988 to 1994 than in 1976 to 1980 (5.2% vs. 3.8%, P < 0.05), greater in males than females, and increased with age in each time period. Among 1988 to 1994 adults, non-Hispanic African Americans had reduced risk of disease compared to non-Hispanic Caucasians (1.7% vs. 5.9%, P < 0.05), and Mexican Americans (1.7% vs. 2.6%, P < 0.05). Also, age-adjusted prevalence was highest in the South (6.6%) and lowest in the West (3.3%). Findings were consistent across gender and multivariate adjusted odds ratios for stone disease history, including all demographic variables, as well as diuretic use, tea or coffee consumption, and dietary intake of calcium, protein, and fat did not materially change the results.ConclusionPrevalence of kidney stone disease history in the United States population increased between 1980 and 1994. A history of stone disease was strongly associated with race/ethnicity and region of residence
Cognitive and neural plasticity in aging: General and task-specific limitations
There is evidence for cognitive as well as neural plasticity across the adult life span, although aging is associated with certain constraints on plasticity. In the current paper, we argue that the age-related reduction in cognitive plasticity may be due to (a) deficits in general processing resources, and (b) failure to engage in task-relevant cognitive operations. Memory-training research suggests that age-related processing deficits (e.g., executive functions, speed) hinder older adults from utilizing mnemonic techniques as efficiently as the young, and that this age difference is reflected by diminished frontal activity during mnemonic use. Additional constraints on memory plasticity in old age are related to difficulties that are specific to the task, such as creating visual images, as well as in binding together the information to be remembered. These deficiencies are paralleled by reduced activity in occipito-parietal and medialâtemporal regions, respectively. Future attempts to optimize intervention-related gains in old age should consider targeting both general processing and task-specific origins of age-associated reductions in cognitive plasticity
Association of APOE É4 and Plasma p-tau181 with Preclinical Alzheimer's Disease and Longitudinal Change in Hippocampus Function
BACKGROUND: The Apolipoprotein E (APOE) É4 allele has been linked to increased tau phosphorylation and tangle formation. APOE É4 carriers with elevated tau might be at the higher risk for AD progression. Previous studies showed that tau pathology begins early in areas of the medial temporal lobe. Similarly, APOE É4 carriers showed altered hippocampal functional integrity. However, it remains unknown whether elevated tau accumulation on hippocampal functional changes would be more pronounced for APOE É4 carriers. OBJECTIVE: We related É4 carriage to levels of plasma phosphorylated tau (p-tau181) up to 15 years prior to AD onset. Furthermore, elevated p-tau181 was explored in relation to longitudinal changes in hippocampal function and connectivity. METHODS: Longitudinal population-based study. Plasma p-tau181 was analyzed in 142 clinically defined Alzheimer's disease (AD) cases and 126 controls. The longitudinal analysis involved 87 non-demented individuals with two waves of plasma samples and three waves of functional magnetic resonance imaging during rest and memory encoding. RESULTS: Increased p-tau181 was observed for both É4 carriers and non-carriers close to AD, but exclusively for É4 carriers in the early preclinical groups (7- and 13-years pre-AD). In É4 carriers, longitudinal p-tau181 increase was paralleled by elevated local hippocampal connectivity at rest and subsequent reduction of hippocampus encoding-related activity. CONCLUSION: Our findings support an association of APOE É4 and p-tau181 with preclinical AD and hippocampus functioning
Restoring Rangelands for Nutrition and Health for Humans and Livestock
Drylands cover 40% of the global land area and host 2 billion people, of which 90% live in low- or middleincome countries. Drylands often face severe land degradation, low agricultural productivity, rapid population growth, widespread poverty, and poor health. Governance structures and institutions are often eroded. Livestock-based livelihoods, largely depending on seasonal migration are common. Pastoralist communities and their land are highly vulnerable to climate shocks, while there are also changes in land tenure, insecurity/conflicts and rapid infrastructure development. Drylands Transform is an interdisciplinary research project revolving around the UN Sustainable Development Goals (SDGs). The project aim is to contribute new knowledge to a transformative change and sustainable development of drylands in East Africa to help escape the ongoing negative spiral of land, livestock and livelihood degradation. We investigate the links between land health, livelihoods, human well-being, and land management and governance with several study sites along the Kenya-Uganda border. Through strong stakeholder engagement we will explore challenges and pathways towards a social-ecological transformation in these drylands. The entry point is the urgent need to identify and enhance synergies between food and nutrition security (SDG2), land and ecosystem health (SDG15) and governance and justice (SDG16) for sustainable dryland development, aiming to improve health and equity (SDGs 3 and 5), while minimizing trade-offs between agricultural productivity, natural resources management and climate change. We are using innovative field research approaches focusing on livelihood improvement through rangeland (grazing areas) restoration and governance interventions. We will present results from the initial work to assess land health using the Land Degradation Surveillance Framework and explore the links with human health and well-being through household survey data. We will also show how we will co-develop sustainable dryland management options (e.g., field experiments with fodder grasses and shrubs) with local communities and set-up knowledge sharing hubs
Can care of elderly be measured? A method for estimating the individual care of recipients in community health care
<p>Abstract</p> <p>Background</p> <p>Almost every country in the Western world has great difficulties allocating enough financial resources to meet the needs in the care of the increasing elderly population. The main problem is common to all countries and concerns the efforts to meet elderly persons' needs on an individual level while still maintaining society's responsibility for distributing justice. The aim of this study is to elaborate an instrument for measuring the quality of individual care and staff's working time in order to allocate public resources fairly. The present study gives an account of a new classification system named TiC (Time in Care), indicating how it can be used most effectively and also investigating the validity and reliability of the system.</p> <p>Methods</p> <p>All recipients in 13 sheltered homes for elderly care (n = 505) in a Swedish municipality were surveyed regarding the care they needed, in dimensions of General Care, Medical Care, Cognitive Dysfunction and Rehabilitation, and the time required. Construct validity was assessed by means of factor analysis. The inter-rater agreement of two raters concerning 79 recipients was measured using weighted Kappa. The stability of the instrument and its sensitivity to change were investigated through test-retest reliability measurements, conducted once a month during a six-month period. The content validity of the instrument was also assessed.</p> <p>Results</p> <p>Factor analysis resulted in a reduction of the number of items from 25 to 16 in three dimensions: General Care, Medical Care and Cognitive Dysfunction. The Kappa analysis showed satisfactory to excellent inter-rater agreement. The care need scores were basically stable but showed sensitivity to change in health status.</p> <p>Conclusion</p> <p>The instrument was found to be useful and reliable for assessing individual needs in community health care.</p
Job strain and risk of obesity: systematic review and meta-analysis of cohort studies
Job strain, the most widely used indicator of work stress, is a risk factor for obesity-related disorders such as cardiovascular disease and type 2 diabetes. However, the extent to which job strain is related to the development of obesity itself has not been systematically evaluated. We carried out a systematic review (PubMed and Embase until May 2014) and meta-analysis of cohort studies to address this issue. Eight studies that fulfilled inclusion criteria showed no overall association between job strain and the risk of weight gain (pooled odds ratio for job strain compared with no job strain 1.04, 95% confidence interval (CI) 0.99-1.09, NTotal=18â240) or becoming obese (1.00, 95% CI 0.89-1.13, NTotal=42â222). In addition, a reduction in job strain over time was not associated with lower obesity risk (1.13, 95% CI 0.90-1.41, NTotal=6507). These longitudinal findings do not support the hypothesis that job strain is an important risk factor for obesity or a promising target for obesity prevention.International Journal of Obesity advance online publication, 30 June 2015; doi:10.1038/ijo.2015.103
Longitudinal dopamine D2 receptor changes and cerebrovascular health in aging
BACKGROUND AND OBJECTIVES: Cross-sectional studies suggest marked dopamine (DA) decline in aging, but longitudinal evidence is lacking. The aim of this study was to estimate within-person decline rates for DA D2-like receptors (DRD2) in aging and examine factors that may contribute to individual differences in DRD2 decline rates. METHODS: We investigated 5-year within-person changes in DRD2 availability in a sample of older adults. At both occasions, PET with 11C-raclopride and MRI were used to measure DRD2 availability in conjunction with structural and vascular brain integrity. RESULTS: Longitudinal analyses of the sample (baseline: n = 181, ages: 64-68 years, 100 men and 81 women; 5-year follow-up: n = 129, 69 men and 60 women) revealed aging-related striatal and extrastriatal DRD2 decline, along with marked individual differences in rates of change. Notably, the magnitude of striatal DRD2 decline was âŒ50% of past cross-sectional estimates, suggesting that the DRD2 decline rate has been overestimated in past cross-sectional studies. Significant DRD2 reductions were also observed in select extrastriatal regions, including hippocampus, orbitofrontal cortex (OFC), and anterior cingulate cortex (ACC). Distinct profiles of correlated DRD2 changes were found across several associative regions (ACC, dorsal striatum, and hippocampus) and in the reward circuit (nucleus accumbens and OFC). DRD2 losses in associative regions were associated with white matter lesion progression, whereas DRD2 losses in limbic regions were related to reduced cortical perfusion. DISCUSSION: These findings provide the first longitudinal evidence for individual and region-specific differences of DRD2 decline in older age and support the hypothesis that cerebrovascular factors are linked to age-related dopaminergic decline
First identification of excited states in the T = 1/2 nucleus Pd
The first experimental information about excited states in the N = Z + 1 nucleus 93Pd is presented. The experiment was performed using a 205 MeV 58Ni beam from the Vivitron accelerator at IReS, Strasbourg, impinging on a bismuth-backed 40Ca target. Gamma-rays, neutrons and charged particles emitted in the reactions were detected using the Ge detector array Euroball, the Neutron Wall liquid-scintillator array and the Euclides Si charged-particle detector system. The experimental level scheme is compared with the results of new shell model calculations which predict a coupling scheme with aligned neutron-proton pairs to greatly influence the level structure of nuclei at low excitation energies
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