Generalized Noiseless Quantum Codes utilizing Quantum Enveloping Algebras

A generalization of the results of Rasetti and Zanardi concerning avoiding errors in quantum computers by using states preserved by evolution is presented. The concept of dynamical symmetry is generalized from the level of classical Lie algebras and groups to the level of dynamical symmetry based on quantum Lie algebras and quantum groups (in the sense of Woronowicz). A natural connection is proved between states preserved by representations of a quantum group and states preserved by evolution with dynamical symmetry of the appropriate universal enveloping algebra. Illustrative examples are discussed.Comment: 10 pages, LaTeX, 2 figures Postscrip

Dynamical Compactification, Standard Cosmology and the Accelerating Universe

A cosmological model based on Kaluza-Klein theory is studied. A metric, in which the scale factor of the compact space evolves as an inverse power of the radius of the observable universe, is constructed. The Freedmann-Robertson-Walker equations of standard four-dimensional cosmology are obtained precisely. The pressure in our universe is an effective pressure expressed in terms of the components of the higher dimensional energy-momentum tensor. In particular, this effective pressure could be negative and might therefore explain the acceleration of our present universe. A special feature of this model is that, for a suitable choice of the parameters of the metric, the higher dimensional gravitational coupling constant could be negative.Comment: 11 pages, uses revte

Adverse childhood experiences, childhood relationships and associated substance use and mental health in young Europeans

Background: Adverse childhood experiences (ACEs) can increase risks of health-harming behaviours and poor health throughout life. While increases in risk may be affected by resilience resources such as supportive childhood relationships, to date few studies have explored these effects. Methods: We combined data from cross-sectional ACE studies among young adults (n = 14 661) in educational institutions in 10 European countries. Nine ACE types, childhood relationships and six health outcomes (early alcohol initiation, problem alcohol use, smoking, drug use, therapy, suicide attempt) were explored. Multivariate modelling estimated relationships between ACE counts, supportive childhood relationships and health outcomes. Results: Almost half (46.2%) of participants reported >= 1 ACE and 5.6% reported >= 4 ACEs. Risks of all outcomes increased with ACE count. In individuals with >= 4 ACEs (vs. 0 ACEs), adjusted odds ratios ranged from 2.01 (95% CIs: 1.70-2.38) for smoking to 17.68 (95% CIs: 12.93-24.17) for suicide attempt. Supportive childhood relationships were independently associated with moderating risks of smoking, problem alcohol use, therapy and suicide attempt. In those with >= 4 ACEs, adjusted proportions reporting suicide attempt reduced from 23% with low supportive childhood relationships to 13% with higher support. Equivalent reductions were 25% to 20% for therapy, 23% to 17% for problem drinking and 34% to 32% for smoking. Conclusions: ACEs are strongly associated with substance use and mental illness. Harmful relationships are moderated by resilience factors such as supportive childhood relationships. Whilst ACEs continue to affect many children, better prevention measures and interventions that enhance resilience to the life-long impacts of toxic childhood stress are required

Polyimide hollow fiber membranes for CO2 separation from wet gas mixtures

Matrimid®5218 hollow fiber membranes were prepared using the dry-wet spinning process. The transport properties were measured with pure gases (H2, CO2, N2, CH4 and O2) and with a mixture (30% CO2 and 70% N2) in dry and wet conditions at 25 ºC, 50 ºC, 60 ºC and 75 ºC and up to 600 kPa. Interesting values of single gas selectivity up to 60 ºC (between 31 and 28 for CO2/N2 and between 33 and 30 for CO2/CH4) in dry condition were obtained. The separation factor measured for the mixture was 20% lower compared to the single gas selectivity, in the whole temperature range analyzed. In saturation conditions the data showed that water influences the performance of the membranes, inducing a reduction of the permeance of all gases. Moreover, the presence of water caused a decrease of single gas selectivity and separation factor, although not so significant, highlighting the very high water resistance of hollow fiber membrane modules

Calming the waters: initiatives for Asia Pacific maritime cooperation

This monograph includes the discussion papers presented at the First Meeting of the Council for Security Cooperation in the Asia Pacific (CSCAP) Maritime Cooperation Working Group held in Kuala Lumpur 2-3 June 1995. The establishment of a Working Group on Maritime Cooperation by CSCAP, as part of its initial work programme, is a reflection of the importance of the maritime environment in the security deliberations of Asia Pacific countries. The Asia Pacific region is distinctively maritime in nature. The sea, and issues to do with the sea, are an important part of international relations in the region, both between regional countries themselves, and between these countries and the rest of the world. The importance of maritime cooperation in the Asia Pacific region flows from the nature and complexity of the regional geographical environment, and the propensity for illegal activities and disputes to occur at sea. Maritime cooperation will contribute to regional stability by easing tension and reducing the risks of conflict while helping to promote a stable maritime regime in the region with the free and uninterrupted flow of seaborne trade, and nations able to pursue their maritime interests and manage their marine resources in an ecologically sustainable manner in accordance with agreed principles of international law. The CSCAP Maritime Co-operation Working Group has adopted a broad view of security, which encompasses a range of small 's' security issues, such as maritime safety, resources conservation, coastal zone management and unlawful activities at sea (such as drug smuggling, illegal population movements and piracy),as well as more conventional maritime security issues. A comprehensive approach to security was explicit in the Group's first meeting programme, which included sessions on shipping, marine science, and the marine environment. The papers in this volume provide a comprehensive review of the main maritime security concerns in the region

Adverse childhood experiences, childhood relationships and associated substance use and mental health in young Europeans

Background: Adverse childhood experiences (ACEs) can increase risks of health-harming behaviours and poor health throughout life. While increases in risk may be affected by resilience resources such as supportive childhood relationships, to date few studies have explored these effects. Methods: We combined data from cross-sectional ACE studies among young adults (n = 14 661) in educational institutions in 10 European countries. Nine ACE types, childhood relationships and six health outcomes (early alcohol initiation, problem alcohol use, smoking, drug use, therapy, suicide attempt) were explored. Multivariate modelling estimated relationships between ACE counts, supportive childhood relationships and health outcomes. Results: Almost half (46.2%) of participants reported ≥1 ACE and 5.6% reported ≥4 ACEs. Risks of all outcomes increased with ACE count. In individuals with ≥4 ACEs (vs. 0 ACEs), adjusted odds ratios ranged from 2.01 (95% CIs: 1.70-2.38) for smoking to 17.68 (95% CIs: 12.93-24.17) for suicide attempt. Supportive childhood relationships were independently associated with moderating risks of smoking, problem alcohol use, therapy and suicide attempt. In those with ≥4 ACEs, adjusted proportions reporting suicide attempt reduced from 23% with low supportive childhood relationships to 13% with higher support. Equivalent reductions were 25% to 20% for therapy, 23% to 17% for problem drinking and 34% to 32% for smoking. Conclusions: ACEs are strongly associated with substance use and mental illness. Harmful relationships are moderated by resilience factors such as supportive childhood relationships. Whilst ACEs continue to affect many children, better prevention measures and interventions that enhance resilience to the life-long impacts of toxic childhood stress are required