10 research outputs found
Largest separable balls around the maximally mixed bipartite quantum state
For finite-dimensional bipartite quantum systems, we find the exact size of
the largest balls, in spectral norms for , of
separable (unentangled) matrices around the identity matrix. This implies a
simple and intutively meaningful geometrical sufficient condition for
separability of bipartite density matrices: that their purity \tr \rho^2 not
be too large. Theoretical and experimental applications of these results
include algorithmic problems such as computing whether or not a state is
entangled, and practical ones such as obtaining information about the existence
or nature of entanglement in states reached by NMR quantum computation
implementations or other experimental situations.Comment: 7 pages, LaTeX. Motivation and verbal description of results and
their implications expanded and improved; one more proof included. This
version differs from the PRA version by the omission of some erroneous
sentences outside the theorems and proofs, which will be noted in an erratum
notice in PRA (and by minor notational differences
Ein axiomatischer zugang zu abhĂ€ngigkeitsmaĂen fĂŒr zufallsvektoren und die spurkorrelation
Genetic and Environmental Influences on the Development of Alcoholism: Resilience vs. Risk
Latent Class Analysis of Lifestyle Characteristics and Health Risk Behaviors among College Youth
Nutritional and Pubertal Status Influences Accuracy of Self-Reported Weight and Height in Adolescents: The HELENA Study
Micronutrients deficiency and associated sociodemographic factors in Chinese children
Background: Although the prevalence of malnutrition has decreased, micronutrient deficiency still exists among children. While iron level has been studied, limited information on serum levels of zinc in Chinese children is available. This study aims to describe the status of micronutrients and its association with sociodemographic factors, and to assess associated risk factors. Methods: A cross-sectional study was performed on 1375 Chinese preschool children. Venous blood samples were collected and analyzed for zinc and iron by atomic absorption spectrophotometry. Sociodemographic information was obtained from self-administered questionnaires given to the parents. Results: The high prevalence of low serum zinc (38.2%) and iron (24.3%) was found. Children from rural preschools had the lowest zinc levels, whereas those from urban preschools had the lowest iron levels. Children living in small houses had the highest prevalence of low serum zinc (47.1%), and children from small families (â€3 persons) had a higher prevalence of low serum zinc than those from large families (41.8% vs. 34.1%). Conclusions: Our findings in the recent socioeconomic development of China suggest the need for continuous monitoring of nutritional factors and highlight the importance of public health implication in preschool children even in developed regions.Jianghong Liu, Yue-Xian Ai, Alexandra Hanlon, Zumin Shi, Barbra Dickerman and Charlene Comphe