128 research outputs found
Comment on 'Operator formalism for the Wigner phase distribution'
The operator associated with the radially integrated Wigner function is found
to lack justification as a phase operator.Comment: 4 pages + 2 figures. A comment on the paper arXiv:1009.4030v1 by T.
Subeesh and V. Sudhir. Updated to the accepted journal versio
Beyond Landauer erasure
In thermodynamics one considers thermal systems and the maximization of
entropy subject to the conservation of energy. A consequence is Landauer's
erasure principle, which states that the erasure of 1 bit of information
requires a minimum energy cost equal to where is the temperature
of a thermal reservoir used in the process and is Boltzmann's constant.
Jaynes, however, argued that the maximum entropy principle could be applied to
any number of conserved quantities which would suggest that information erasure
may have alternative costs. Indeed we showed recently that by using a reservoir
comprising energy degenerate spins and subject to conservation of angular
momentum, the cost of information erasure is in terms of angular momentum
rather than energy. Here we extend this analysis and derive the minimum cost of
information erasure for systems where different conservation laws operate. We
find that, for each conserved quantity, the minimum resource needed to erase 1
bit of memory is where is related to the average
value of the conserved quantity. The costs of erasure depend, fundamentally, on
both the nature of the physical memory element and the reservoir with which it
is coupled.Comment: 7 pages, 3 figure
Is coherence catalytic?
Quantum coherence, the ability to control the phases in superposition states
is a resource, and it is of crucial importance, therefore, to understand how it
is consumed in use. It has been suggested that catalytic coherence is possible,
that is repeated use of the coherence without degradation or reduction in
performance. The claim has particular relevance for quantum thermodynamics
because, were it true, it would allow free energy that is locked in coherence
to be extracted . We address this issue directly with a
careful analysis of the proposal by berg. We find that coherence
be used catalytically, or even repeatedly without limit.Comment: 23 pages with 2 figure
Sex and Race/Ethnic Disparities in Food Security and Chronic Diseases in U.S. Older Adults
Objective: The purpose of this study was to determine the relationships among sex, race/ethnicity, and food security with the likelihood of cancer, diabetes, cardiovascular disease, and lung disease for older adults. Method: Complex sample analysis by logistic regression models for chronic diseases were conducted from National Health and Nutrition Examination Surveys, 2011 to 2012 and 2013 to 2014, for N = 3,871 adults aged â„55 years. Results: Being female with low food security was associated with lung disease and diabetes. Poverty, rather than low food security, was associated with cardiovascular diseases. Minority status was independently associated with low food security and diabetes. Discussion: Food insecurity, sex, and race/ethnicity were associated with chronic diseases in a representative sample of U.S. older adults
Obesity Indicators by Race/Ethnicity for Diagnosis of Cardiometabolic Diseases for a US Representative Sample of Adults
Background: Obesity, a growing epidemic, is a preventable risk factor for cardiometabolic diseases. Obesity and cardiometabolic diseases affect Hispanics and African Americans more than non-Hispanic Caucasians. This study examined the relationship among race/ethnicity, obesity diagnostic measures (body mass index, waist circumference, subscapular and triceps skinfold thickness), and cardiometabolic risk factors (hyperglycemia, high, non-high-density lipoprotein cholesterol, low, high-density lipoprotein cholesterol, and hypertension) for adults across the United States.
Methods: Using data from two-cycles of the National Health and Examination Survey (NHANES) 2007-2010, and accounting for the complex sample design, logistic regression models were conducted comparing obesity indicators in Mexican Americans, other Hispanics, and Black non-Hispanics, with White non-Hispanics and their associations with the presence of cardiometabolic diseases.
Results: Differences by race/ethnicity were found for subscapular skinfold thickness and hyperglycemia. Waist circumference and subscapular skinfold were positively associated with the presence of hyperglycemia; dyslipidemia, and hypertension across race/ ethnicity, adjusting for age, gender, smoking, physical activity, education, income to poverty index, and health insurance. Race/ ethnicity did not influence the association of any obesity indicators with the tested cardiometabolic diseases. All obesity measures except triceps skinfold were associated with hyperglycemia.
Conclusions: We suggest that subscapular skinfold thickness be considered as an inexpensive non-intrusive screening tool for cardiometabolic risk factors in an adult US populatio
Relationship of Lifestyle Medical Advice and Non-HDL Cholesterol Control of a Nationally Representative US Sample with Hypercholesterolemia by Race/Ethnicity
Objective: The main purpose of this study was to evaluate the associations of lifestyle medical advice and non-HDL cholesterol control of a nationally representative US sample of adults with hypercholesterolemia by race/ethnicity.
Methods: Data were collected by appending sociodemographic, anthropometric, and laboratory data from two cycles of the National Health and Nutrition Survey (2007-2008 and 2009-2010). This study acquired data from male and female adults aged â„â20 years (Nâ=â11,577), classified as either Mexican American (MA), (), other Hispanic (OH) (), Black non-Hispanic (BNH) (), or White non-Hispanic (WNH) ().
Results: Minorities were more likely to report having received dietary, weight management, and exercise recommendations by healthcare professionals than WNH, adjusting for confounders. Approximately 80% of those receiving medical advice followed the recommendation, regardless of race/ethnicity. Of those who received medical advice, reporting âcurrently controlling or losing weightâ was associated with lower non-HDL cholesterol. BNH who reported âcurrently controlling or losing weightâ had higher non-HDL cholesterol than WNH who reported following the advice.
Conclusion: The results suggest that current methods of communicating lifestyle advice may not be adequate across race/ethnicity and that a change in perspective and delivery of medical recommendations for persons with hypercholesterolemia is needed
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