210 research outputs found

    The role of coherence entropy of physical twin observables in entanglement

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    The concept of physical twin observables (PTO) for bipartite quantum states,introduced and proved relevant for quantum information theory in recent work, is substantially simplified. The relation of observable and state is studied in detail from the point of view of coherence entropy. Properties of this quantity are further explored. It is shown that, besides for pure states, quantum discord (measure of entanglement) can be expressed through the coherence entropy of a PTO complete in relation to the state.Comment: 19 pages, Latex+Revtex

    Mixed-state twin observables

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    Twin observables, i.e. opposite subsystem observables A+ and A- that are indistinguishable in measurement in a given mixed or pure state W, are investigated in detail algebraicly and geometrically. It is shown that there is a far-reaching correspondence between the detectable (in W) spectral entities of the two operators. Twin observables are state-dependently quantum-logically equivalent, and direct subsystem measurement of one of them ipso facto gives rise to the indirect (i.e. distant) measurement of the other. Existence of nontrivial twins requires singularity of W. Systems in thermodynamic equilibrium do not admit subsystem twins. These observables may enable one to simplify the matrix representing W.Comment: 13 page

    Unique Aggregation of Sterigmatocystin in Water Yields Strong and Specific Circular Dichroism Response Allowing Highly Sensitive and Selective Monitoring of Bio-Relevant Interactions

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    We demonstrated the hitherto unknown property of the mycotoxin sterigmatocystin (STC) to provide homogeneous solutions in aqueous medium by forming a unique aggregate type (not formed by analogous aflatoxins), characterized by exceptionally strong circular dichroism (CD) bands in the 300-400 nm range. Results showed that these CD bands do not originate from intrinsic STC chirality but are a specific property of a peculiar aggregation process similar to psi-DNA CD response. Transmission electron microscopy (TEM) experiments revealed a fine fiber network resembling a supramolecular gel structure with helical fibers. Thermodynamic studies of aggregates by differential scanning calorimetry (DSC) revealed high reversibility of the dominant aggregation process. We demonstrated that the novel STC psi-CD band at 345 nm could be applied at biorelevant conditions (100 nanomolar concentration) and even in marine-salt content conditions for specific and quantitative monitoring of STC. Also, we showed that STC strongly non-covalently interacts with ds-DNA with likely toxic effects, thus contrary to the previous belief requiring prior enzyme epoxidation

    The role of wages in the migration of health care professionals from developing countries

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    Several countries are increasingly relying on immigration as a means of coping with domestic shortages of health care professionals. This trend has led to concerns that in many of the source countries – especially within Africa – the outflow of health care professionals is adversely affecting the health care system. This paper examines the role of wages in the migration decision and discusses the likely effect of wage increases in source countries in slowing migration flows. This paper uses data on wage differentials in the health care sector between source country and receiving country (adjusted for purchasing power parity) to test the hypothesis that larger wage differentials lead to a larger supply of health care migrants. Differences in other important factors affecting migration are discussed and, where available, data are presented. There is little correlation between the supply of health care migrants and the size of the wage differential between source and destination country. In cases where data are available on other factors affecting migration, controlling for these factors does not affect the result. At current levels, wage differentials between source and destination country are so large that small increases in health care wages in source countries are unlikely to affect significantly the supply of health care migrants. The results suggest that non-wage instruments might be more effective in altering migration flows

    A technical framework for costing health workforce retention schemes in remote and rural areas

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    <p>Abstract</p> <p>Background</p> <p>Increasing the availability of health workers in remote and rural areas through improved health workforce recruitment and retention is crucial to population health. However, information about the costs of such policy interventions often appears incomplete, fragmented or missing, despite its importance for the sound selection, planning, implementation and evaluation of these policies. This lack of a systematic approach to costing poses a serious challenge for strong health policy decisions.</p> <p>Methods</p> <p>This paper proposes a framework for carrying out a costing analysis of interventions to increase the availability of health workers in rural and remote areas with the aim to help policy decision makers. It also underlines the importance of identifying key sources of financing and of assessing financial sustainability.</p> <p>The paper reviews the evidence on costing interventions to improve health workforce recruitment and retention in remote and rural areas, provides guidance to undertake a costing evaluation of such interventions and investigates the role and importance of costing to inform the broader assessment of how to improve health workforce planning and management.</p> <p>Results</p> <p>We show that while the debate on the effectiveness of policies and strategies to improve health workforce retention is gaining impetus and attention, there is still a significant lack of knowledge and evidence about the associated costs. To address the concerns stemming from this situation, key elements of a framework to undertake a cost analysis are proposed and discussed.</p> <p>Conclusions</p> <p>These key elements should help policy makers gain insight into the costs of policy interventions, to clearly identify and understand their financing sources and mechanisms, and to ensure their sustainability.</p

    Monte Carlo and analytic modeling of an Elekta Infinity linac with Agility MLC: Investigating the significance of accurate model parameters for small radiation fields

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    Purpose: To explain the deviation observed between measured and Monaco calculated dose profiles for a small field (i.e., alternating open-closed MLC pattern). A Monte Carlo (MC) model of an Elekta Infinity linac with Agility MLC was created and validated against measurements. In addition, an analytic model which predicts the fluence at the isocenter plane was used to study the impact of multiple beam parameters on the accuracy of dose calculations for small fields. Methods: A detailed MC model of a 6 MV Elekta Infinity linac with Agility MLC was created in EGSnrc/BEAMnrc and validated against measurements. An analytic model using primary and secondary virtual photon sources was created and benchmarked against the MC simulations and the impact of multiple beam parameters on the accuracy of the model for a small field was investigated. Both models were used to explain discrepancies observed between measured/EGSnrc simulated and Monaco calculated dose profiles for alternating open-closed MLC leaves. Results: MC-simulated dose profiles (PDDs, cross- and in-line profiles, etc.) were found to be in very good agreements with measurements. The bes

    The use of discrete choice experiments to inform health workforce policy: a systematic review.

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    BACKGROUND: Discrete choice experiments have become a popular study design to study the labour market preferences of health workers. Discrete choice experiments in health, however, have been criticised for lagging behind best practice and there are specific methodological considerations for those focused on job choices. We performed a systematic review of the application of discrete choice experiments to inform health workforce policy. METHODS: We searched for discrete choice experiments that examined the labour market preferences of health workers, including doctors, nurses, allied health professionals, mid-level and community health workers. We searched Medline, Embase, Global Health, other databases and grey literature repositories with no limits on date or language and contacted 44 experts. Features of choice task and experimental design, conduct and analysis of included studies were assessed against best practice. An assessment of validity was undertaken for all studies, with a comparison of results from those with low risk of bias and a similar objective and context. RESULTS: Twenty-seven studies were included, with over half set in low- and middle-income countries. There were more studies published in the last four years than the previous ten years. Doctors or medical students were the most studied cadre. Studies frequently pooled results from heterogeneous subgroups or extrapolated these results to the general population. Only one third of studies included an opt-out option, despite all health workers having the option to exit the labour market. Just five studies combined results with cost data to assess the cost effectiveness of various policy options. Comparison of results from similar studies broadly showed the importance of bonus payments and postgraduate training opportunities and the unpopularity of time commitments for the uptake of rural posts. CONCLUSIONS: This is the first systematic review of discrete choice experiments in human resources for health. We identified specific issues relating to this application of which practitioners should be aware to ensure robust results. In particular, there is a need for more defined target populations and increased synthesis with cost data. Research on a wider range of health workers and the generalisability of results would be welcome to better inform policy

    Developing a Standard Set of Patient-centred Outcomes for Adult Oral Health - An International, Cross-disciplinary Consensus.

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    OBJECTIVE: To develop a minimum Adult Oral Health Standard Set (AOHSS) for use in clinical practice, research, advocacy and population health. MATERIALS AND METHODS: An international oral health working group (OHWG) was established, of patient advocates, researchers, clinicians and public health experts to develop an AOHSS. PubMed was searched for oral health clinical and patient-reported measures and case-mix variables related to caries and periodontal disease. The selected patient-reported outcome measures focused on general oral health, and oral health-related quality of life tools. A consensus was reached via Delphi with parallel consultation of subject matter content experts. Finally, comments and input were elicited from oral health stakeholders globally, including patients/consumers. RESULTS: The literature search yielded 1,453 results. After inclusion/exclusion criteria, 959 abstracts generated potential outcomes and case-mix variables. Delphi rounds resulted in a consensus-based selection of 80 individual items capturing 31 outcome and case-mix concepts. Global reviews generated 347 responses from 87 countries, and the patient/consumer validation survey elicited 129 responses. This AOHSS includes 25 items directed towards patients (including demographics, the impact of their oral health on oral function, a record of pain and oral hygiene practices, and financial implications of care) and items for clinicians to complete, including medical history, a record of caries and periodontal disease activity, and types of dental treatment delivered. CONCLUSION: In conclusion, utilising a robust methodology, a standardised core set of oral health outcome measures for adults, with a particular emphasis on caries and periodontal disease, was developed

    Health worker motivation in Africa: the role of non-financial incentives and human resource management tools

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    BACKGROUND: There is a serious human resource crisis in the health sector in developing countries, particularly in Africa. One of the challenges is the low motivation of health workers. Experience and the evidence suggest that any comprehensive strategy to maximize health worker motivation in a developing country context has to involve a mix of financial and non-financial incentives. This study assesses the role of non-financial incentives for motivation in two cases, in Benin and Kenya. METHODS: The study design entailed semi-structured qualitative interviews with doctors and nurses from public, private and NGO facilities in rural areas. The selection of health professionals was the result of a layered sampling process. In Benin 62 interviews with health professionals were carried out; in Kenya 37 were obtained. Results from individual interviews were backed up with information from focus group discussions. For further contextual information, interviews with civil servants in the Ministry of Health and at the district level were carried out. The interview material was coded and quantitative data was analysed with SPSS software. RESULTS AND DISCUSSION: The study shows that health workers overall are strongly guided by their professional conscience and similar aspects related to professional ethos. In fact, many health workers are demotivated and frustrated precisely because they are unable to satisfy their professional conscience and impeded in pursuing their vocation due to lack of means and supplies and due to inadequate or inappropriately applied human resources management (HRM) tools. The paper also indicates that even some HRM tools that are applied may adversely affect the motivation of health workers. CONCLUSION: The findings confirm the starting hypothesis that non-financial incentives and HRM tools play an important role with respect to increasing motivation of health professionals. Adequate HRM tools can uphold and strengthen the professional ethos of doctors and nurses. This entails acknowledging their professionalism and addressing professional goals such as recognition, career development and further qualification. It must be the aim of human resources management/quality management (HRM/QM) to develop the work environment so that health workers are enabled to meet their personal and the organizational goals
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