193 research outputs found

    Remarks on effective action and entanglement entropy of Maxwell field in generic gauge

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    We analyze the dependence of the effective action and the entanglement entropy in the Maxwell theory on the gauge fixing parameter aa in dd dimensions. For a generic value of aa the corresponding vector operator is nonminimal. The operator can be diagonalized in terms of the transverse and longitudinal modes. Using this factorization we obtain an expression for the heat kernel coefficients of the nonminimal operator in terms of the coefficients of two minimal Beltrami-Laplace operators acting on 0- and 1-forms. This expression agrees with an earlier result by Gilkey et al. Working in a regularization scheme with the dimensionful UV regulators we introduce three different regulators: for transverse, longitudinal and ghost modes, respectively. We then show that the effective action and the entanglement entropy do not depend on the gauge fixing parameter aa provided the certain (aa-dependent) relations are imposed on the regulators. Comparing the entanglement entropy with the black hole entropy expressed in terms of the induced Newton's constant we conclude that their difference, the so-called Kabat's contact term, does not depend on the gauge fixing parameter aa. We consider this as an indication of gauge invariance of the contact term.Comment: 15 pages; v2: typos in eqs. (31), (32), (34), (36) corrected; discussion in section 6 expande

    Mindfulness-based interventions for people diagnosed with a current episode of an anxiety or depressive disorder: a meta-analysis of randomised controlled trials

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    Objective Mindfulness-based interventions (MBIs) can reduce risk of depressive relapse for people with a history of recurrent depression who are currently well. However, the cognitive, affective and motivational features of depression and anxiety might render MBIs ineffective for people experiencing current symptoms. This paper presents a meta-analysis of randomised controlled trials (RCTs) of MBIs where participants met diagnostic criteria for a current episode of an anxiety or depressive disorder. Method Post-intervention between-group Hedges g effect sizes were calculated using a random effects model. Moderator analyses of primary diagnosis, intervention type and control condition were conducted and publication bias was assessed. Results Twelve studies met inclusion criteria (n = 578). There were significant post-intervention between-group benefits of MBIs relative to control conditions on primary symptom severity (Hedges g = −0.59, 95% CI = −0.12 to −1.06). Effects were demonstrated for depressive symptom severity (Hedges g = −0.73, 95% CI = −0.09 to −1.36), but not for anxiety symptom severity (Hedges g = −0.55, 95% CI = 0.09 to −1.18), for RCTs with an inactive control (Hedges g = −1.03, 95% CI = −0.40 to −1.66), but not where there was an active control (Hedges g = 0.03, 95% CI = 0.54 to −0.48) and effects were found for MBCT (Hedges g = −0.39, 95% CI = −0.15 to −0.63) but not for MBSR (Hedges g = −0.75, 95% CI = 0.31 to −1.81). Conclusions This is the first meta-analysis of RCTs of MBIs where all studies included only participants who were diagnosed with a current episode of a depressive or anxiety disorder. Effects of MBIs on primary symptom severity were found for people with a current depressive disorder and it is recommended that MBIs might be considered as an intervention for this population

    Mindfulness as a General Ingredient of Successful Psychotherapy

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    In this chapter I present a psychological conceptualization of mindfulness based on constructs in common therapeutic parlance. Taking a functional approach based on the skills and recognitions patients gain from the exercises commonly used in mindfulness training and avoiding exotic and cryptic language, it makes apparent both the commonality mindfulness has with modalities therapists will be already using in their clinical practice and the ways in which it may add something new and therapeutically useful. It also describes the evolutionary pressures that have shaped the biological imperatives driving the default movements of attention that result in day-to-day experience being experienced as less than pleasant; defaults that result in both the need for, and the challenge of cultivating mindfulness. So, while the instructions and narrative within which these principles are introduced into therapy will need to be adapted to the patient’s background and circumstances, an understanding and grounding in the principles enables the therapist both to skillfully make these adaptations to the training exercises and to make them immediately sensible to the patient, including the challenges they will meet in getting started

    Columnar cell lesions and subsequent breast cancer risk: a nested case-control study

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    Introduction: Histologic and genetic evidence suggests that at least some columnar cell lesions (CCL) of the breast represent precursor lesions in the low-grade breast neoplasia pathway. However, the risk of subsequent breast cancer associated with the presence of CCL in a benign breast biopsy is poorly understood.Methods The authors examined the association between the presence of CCL and subsequent breast cancer risk in a nested case-control study of benign breast disease (BBD) and breast cancer within the Nurses' Health Studies (394 cases, 1,606 controls). Benign breast biopsy slides were reviewed by pathologists and CCL presence assessed. Logistic regression was used to compute odds ratios (ORs) and 95% confidence intervals (CIs) for the association between CCL and breast cancer risk. Results: Women with CCL (140 cases, 448 controls) had an increased risk of breast cancer compared with those without CCL (OR = 1.44, 95% CI: 1.14 to 1.83), although this was attenuated and became non-significant after adjustment for the histologic category of BBD (OR = 1.20, 95% CI: 0.94 to 1.54). CCL presence was associated with the greatest risk of breast cancer for those with nonproliferative BBD (OR = 1.36, 95% CI: 0.79 to 2.37) and the lowest risk for those with atypical hyperplasia (AH) (OR = 1.10, 95% CI: 0.65 to 1.87); however, this apparent heterogeneity in risk across BBD categories was not significant (P for interaction between CCL presence and BBD category = 0.77). Conclusions: These results provide evidence that CCL may be an important marker of breast cancer risk in women with BBD but suggest that CCL do not increase breast cancer risk independently of concurrent proliferative changes in the breast

    A portable RNA sequence whose recognition by a synthetic antibody facilitates structural determination

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    RNA crystallization and phasing represent major bottlenecks in RNA structure determination. Seeking to exploit antibody fragments as RNA crystallization chaperones, we have used an arginine-enriched synthetic Fab library displayed on phage to obtain Fabs against the class I ligase ribozyme. We solved the structure of a Fab–ligase complex at 3.1-Å resolution using molecular replacement with Fab coordinates, confirming the ribozyme architecture and revealing the chaperone's role in RNA recognition and crystal contacts. The epitope resides in the GAAACAC sequence that caps the P5 helix, and this sequence retains high-affinity Fab binding within the context of other structured RNAs. This portable epitope provides a new RNA crystallization chaperone system that easily can be screened in parallel to the U1A RNA-binding protein, with the advantages of a smaller loop and Fabs′ high molecular weight, large surface area and phasing power.National Institutes of Health (U.S.) (GM61835

    Specific Binding of the Pathogenic Prion Isoform: Development and Characterization of a Humanized Single-Chain Variable Antibody Fragment

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    Murine monoclonal antibody V5B2 which specifically recognizes the pathogenic form of the prion protein represents a potentially valuable tool in diagnostics or therapy of prion diseases. As murine antibodies elicit immune response in human, only modified forms can be used for therapeutic applications. We humanized a single-chain V5B2 antibody using variable domain resurfacing approach guided by computer modelling. Design based on sequence alignments and computer modelling resulted in a humanized version bearing 13 mutations compared to initial murine scFv. The humanized scFv was expressed in a dedicated bacterial system and purified by metal-affinity chromatography. Unaltered binding affinity to the original antigen was demonstrated by ELISA and maintained binding specificity was proved by Western blotting and immunohistochemistry. Since monoclonal antibodies against prion protein can antagonize prion propagation, humanized scFv specific for the pathogenic form of the prion protein might become a potential therapeutic reagent

    Meditation on the Soles of the Feet Practice Provides Some Control of Aggression for Individuals with Alzheimer’s Disease

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    Alzheimer’s disease is a progressive neurodegenerative condition that affects cognition, mental and physical health, and functionality of older people. As the disease progresses from the mild to moderate stage, there is a concomitant increase in several behavioral variables, chiefly agitation, anger, and aggression. Currently, there are no evidence-based treatments for these behaviors in this population. Three individuals with moderate Alzheimer’s disease were taught an informal mindfulness practice, meditation on the Soles of the Feet (SoF), as a self-management strategy within a multiple-baseline design across participants. All three were able to learn and use the SoF practice to manage their verbal and physical aggression. Their use of the SoF practice was correlated with decreased perceived psychological stress for their spouses and caregivers, as well as for the participants, but to a much smaller degree. In terms of social validity, the participants, their spouses, and caregivers rated the SoF practice as acceptable, effective, with no unintended effects, and indicated that they would recommend the practice to others. However, they also rated SoF as effortful for the participants because it involves the participants remembering to use the practice with rising anger, a requirement particularly challenging for those with memory problems. The SoF practice may enable individuals in the early stages of dementia to manage their anger and aggression. The data were derived from an internally valid experimental design, suggestive of initial proof-of-concept, but needs to be replicated before any clinical implications can be imputed from this study
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