1,250 research outputs found

    Entanglement trapping in a non-stationary structured reservoir

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    We study a single two-level atom interacting with a reservoir of modes defined by a reservoir structure function with a frequency gap. Using the pseudomodes technique, we derive the main features of a trapping state formed in the weak coupling regime. Utilising different entanglement measures we show that strong correlations and entanglement between the atom and the modes are in existence when this state is formed. Furthermore, an unexpected feature for the reservoir is revealed. In the long time limit and for weak coupling the reservoir spectrum is not constant in time.Comment: 10 pages, 16 figure

    DBT, FAP, and ACT: How empirically oriented are the new behavior therapy technologies?

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    Empirically validated methods for reducing stigma and prejudice toward recipients of behavioral healthcare services are badly needed. In the present study, two packages presented in one day workshops were compared to a biologically oriented Educational Control condition in the alleviation of stigmatizing attitudes in drug abuse counselors. One, Acceptance and Commitment Training (ACT), utilized acceptance, defusion, mindfulness, and values methods. The other, Multicultural Training, sensitized participants to group prejudices and biases. Measures of stigma and burnout were taken pre-training, post-training, and after a three month follow-up. Results showed that Multicultural Training had an impact on stigmatizing attitudes and burnout post-intervention but not at follow-up, but showed better gains in a sense of personal accomplishment as compared to the Educational Control at follow-up. ACT had a positive impact on stigma at follow-up and on burnout at post-treatment and follow-up and follow-up gains in burnout exceeded those of Multicultural Training. ACT also significantly changed the believability of stigmatizing attitudes. This process mediated the impact of ACT but not Multicultural Training on follow-up stigma and burnout. This preliminary study opens new avenues for reducing stigma and burnout in behavioral health counselors

    Linear optical properties of organic microcavity polaritons with non-Markovian Quantum State Diffusion

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    Hybridisation of the cavity modes and the excitons to polariton states together with the coupling to the vibrational modes determine the linear optical properties of organic semiconductors in microcavities. In this article we compute the refractive index for such system using the Holstein-Tavis-Cummings model and determine then the linear optical properties using the transfer matrix method. We first extract the parameters for the exciton in our model from fitting to experimentally measured absorption of a 2,7-bis [9,9-di(4-methylphenyl)-fluoren-2-yl]-9,9-di(4-methylphenyl) fluorene (TDAF) molecular thin film. Then we compute the reflectivity of such a thin film in a metal clad microcavity system by including the dispersive microcavity mode to the model. We compute susceptibility of the model systems evolving just a single state vector by using the non-Markovian Quantum State Diffusion. The computed location and height of the lower and upper polaritons agree with the experiment within the estimated errorbars for small angles (30\leq 30^\circ). For larger angles the location of the polariton resonances are within the estimated error.Comment: 10 pages, 4 figure

    Local in time master equations with memory effects: Applicability and interpretation

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    Non-Markovian local in time master equations give a relatively simple way to describe the dynamics of open quantum systems with memory effects. Despite their simple form, there are still many misunderstandings related to the physical applicability and interpretation of these equations. Here we clarify these issues both in the case of quantum and classical master equations. We further introduce the concept of a classical non-Markov chain signified through negative jump rates in the chain configuration.Comment: Special issue on loss of coherence and memory effects in quantum dynamics, J. Phys. B., to appea

    Identifying the origin of delayed electroluminescence in a polariton organic light-emitting diode

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    Modifying the energy landscape of existing molecular emitters is an attractive challenge with favourable outcomes in chemistry and organic optoelectronic research. It has recently been explored through strong light-matter coupling studies where the organic emitters were placed in an optical cavity. Nonetheless, a debate revolves around whether the observed change in the material properties represents novel coupled system dynamics or the unmasking of pre-existing material properties induced by light-matter interactions. Here, for the first time, we examined the effect of strong coupling in polariton organic light-emitting diodes via time-resolved electroluminescence studies. We accompanied our experimental analysis with theoretical fits using a model of coupled rate equations accounting for all major mechanisms that can result in delayed electroluminescence in organic emitters. We found that in our devices the delayed electroluminescence was dominated by emission from trapped charges and this mechanism remained unmodified in the presence of strong coupling.Comment: 11 pages + 8 supp pages, 4 figures + 8 supp figure

    The failure of suicide prevention in primary care: family and GP perspectives - a qualitative study

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    Background Although Primary care is crucial for suicide prevention, clinicians tend to report completed suicides in their care as non-preventable. We aimed to examine systemic inadequacies in suicide prevention from the perspectives of bereaved family members and GPs.Methods Qualitative study of 72 relatives or close friends bereaved by suicide and 19 General Practitioners who have experienced the suicide of patients.Results Relatives highlight failures in detecting symptoms and behavioral changes and the inability of GPs to understand the needs of patients and their social contexts. A perceived overreliance on anti-depressant treatment is a major source of criticism by family members. GPs tend to lack confidence in the recognition and management of suicidal patients, and report structural inadequacies in service provision.Conclusions Mental health and primary care services must find innovative and ethical ways to involve families in the decision-making process for patients at risk of suicide

    QTL/microarray approach using pathway information

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    <p>Abstract</p> <p>Background</p> <p>A combined quantitative trait loci (QTL) and microarray-based approach is commonly used to find differentially expressed genes which are then identified based on the known function of a gene in the biological process governing the trait of interest. However, a low cutoff value in individual gene analyses may result in many genes with moderate but meaningful changes in expression being missed.</p> <p>Results</p> <p>We modified a gene set analysis to identify intersection sets with significantly affected expression for which the changes in the individual gene sets are less significant. The gene expression profiles in liver tissues of four strains of mice from publicly available microarray sources were analyzed to detect trait-associated pathways using information on the QTL regions of blood concentrations of high density lipoproteins (HDL) cholesterol and insulin-like growth factor 1 (IGF-1). Several metabolic pathways related to HDL levels, including lipid metabolism, ABC transporters and cytochrome P450 pathways were detected for HDL QTL regions. Most of the pathways identified for the IGF-1 phenotype were signal transduction pathways associated with biological processes for IGF-1's regulation.</p> <p>Conclusion</p> <p>We have developed a method of identifying pathways associated with a quantitative trait using information on QTL. Our approach provides insights into genotype-phenotype relations at the level of biological pathways which may help to elucidate the genetic architecture underlying variation in phenotypic traits.</p

    Caries inhibitory effect of fluoridated sugar in a trial in Indonesia

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    The document attached has been archived with permission from the Australian Dental Association. An external link to the publisher’s copy is included.Background: In some regional areas of Indonesia, caries prevalence is increasing rapidly. As water, salt or milk fluoridation were not considered suitable for use throughout Indonesia, and fluoridated tooth paste is mostly too expensive, a fluoride cocrystallised sugar containing 10ppm fluoride was prepared. Its efficacy in inhibiting caries development was tested in a field trial. Methods: The field trial was established in Medan, Sumatera. All dietary background data necessary to ensure the safety of a trial were collected. Subjects chosen were 176 children who were residents of two orphanages and a boarding school for children of poor rural families. The trial used a double-blind format. Close monitoring of fluoride consumption was maintained, and fluoride excretion rates were assessed six monthly by urinary fluoride analysis. Results: Records of total tooth surface caries present initially and after 18 months of sugar supply showed that the children using fluoridated sugar had significantly fewer carious lesions than those who used normal sugar. Conclusion: This result indicates that sugar might be considered as a further vehicle for supplementary dietary fluoride in communities where there is a high caries prevalence or high caries risk and little exposure to fluoride.Mulyani, J McIntyr

    Confronting the vicinity of the surface water and sea shore in a shallow glaciogenic aquifer in southern Finland

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    The groundwater in a shallow, unconfined, low-lying coastal aquifer in Santala, southern Finland, was chemically characterised by integrating multivariate statistical approaches, principal component analysis (PCA) and hierarchical cluster analysis (HCA), based on the stable isotopes delta H-2 and delta O-18, hydrogeochemistry and field monitoring data. PCA and HCA yielded similar results and classified groundwater samples into six distinct groups that revealed the factors controlling temporal and spatial variations in the groundwater geochemistry, such as the geology, anthropogenic sources from human activities, climate and surface water. High temporal variation in groundwater chemistry directly corresponded to precipitation. With an increase in precipitation, KMnO4 consumption, EC, alkalinity and Ca concentrations also increased in most wells, while Fe, Al, Mn and SO4 were occasionally increased during spring after the snowmelt under specific geological conditions. The continued increase in NO3 and metal concentrations in groundwater indicates the potential contamination risk to the aquifer. Stable isotopes of delta O-18 and delta H-2 indicate groundwater recharge directly from meteoric water, with an insignificant contribution from lake water, and no seawater intrusion into the aquifer. Groundwater geochemistry suggests that local seawater intrusion is temporarily able to take place in the sulfate reduction zone along the freshwater and seawater mixed zone in the low-lying coastal area, but the contribution of seawater was found to be very low. The influence of lake water could be observed from higher levels of KMnO4 consumption in wells near the lake. The integration of PCA and HCA with conventional classification of groundwater types, as well as with the hydrogeochemical data, provided useful tools to identify the vulnerable groundwater areas representing the impacts of both natural and human activities on water quality and the understanding of complex groundwater flow system for the aquifer vulnerability assessment and groundwater management in the future.Peer reviewe
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