672 research outputs found
Higher harmonics of ac voltage response in narrow strips of YBa2Cu3O7 thin films: Evidence for strong thermal fluctuations
We report on measurements of higher harmonics of the ac voltage response in
strips of YBa2Cu3O7 thin films as a function of temperature, frequency and ac
current amplitude. The third (fifth) harmonic of the local voltage is found to
exhibit a negative (positive) peak at the superconducting transition
temperature and their amplitudes are closely related to the slope (derivative)
of the first (Ohmic) harmonic. The peaks practically do not depend on frequency
and no even (second or fourth) harmonics are detected. The observed data can be
interpreted in terms of ac current induced thermal modulation of the sample
temperature added to strong thermally activated fluctuations in the transition
region.Comment: 9 pages, 4 figures (PDF file
The Role of Parvalbumin-positive Interneurons in Auditory Steady-State Response Deficits in Schizophrenia
© The Author(s) 2019. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.Despite an increasing body of evidence demonstrating subcellular alterations in parvalbumin-positive (PV+) interneurons in schizophrenia, their functional consequences remain elusive. Since PV+ interneurons are involved in the generation of fast cortical rhythms, these changes have been hypothesized to contribute to well-established alterations of beta and gamma range oscillations in patients suffering from schizophrenia. However, the precise role of these alterations and the role of different subtypes of PV+ interneurons is still unclear. Here we used a computational model of auditory steady-state response (ASSR) deficits in schizophrenia. We investigated the differential effects of decelerated synaptic dynamics, caused by subcellular alterations at two subtypes of PV+ interneurons: basket cells and chandelier cells. Our simulations suggest that subcellular alterations at basket cell synapses rather than chandelier cell synapses are the main contributor to these deficits. Particularly, basket cells might serve as target for innovative therapeutic interventions aiming at reversing the oscillatory deficits.Peer reviewe
Granularity-induced gapless superconductivity in NbN films: evidence of thermal phase fluctuations
Using a single coil mutual inductance technique, we measure the low
temperature dependence of the magnetic penetration depth in superconducting NbN
films prepared with similar critical temperatures around 16 K but with
different microstructures. Only (100) epitaxial and weakly granular (100)
textured films display the characteristic exponential dependence of
conventional BCS s-wave superconductors. More granular (111) textured films
exhibit a linear dependence, indicating a gapless state in spite of the s-wave
gap. This result is quantitatively explained by a model of thermal phase
fluctuations favored by the granular structure.Comment: 10 pages, 4 figures, to appear in Phys. Rev.
In vivo evaluation of a vibration analysis technique for the per-operative monitoring of the fixation of hip prostheses
<p>Abstract</p> <p>Background</p> <p>The per-operative assessment of primary stem stability may help to improve the performance of total hip replacement. Vibration analysis methods have been successfully used to assess dental implant stability, to monitor fracture healing and to measure bone mechanical properties. The objective of the present study was to evaluate in vivo a vibration analysis-based endpoint criterion for the insertion of the stem by successive surgeon-controlled hammer blows.</p> <p>Methods</p> <p>A protocol using a vibration analysis technique for the characterisation of the primary bone-prosthesis stability was tested in 83 patients receiving a custom-made, intra-operatively manufactured stem prosthesis. Two groups were studied: one (n = 30) with non cemented and one (n = 53) with partially cemented stem fixation. Frequency response functions of the stem-femur system corresponding to successive insertion stages were compared.</p> <p>Results</p> <p>The correlation coefficient between the last two frequency response function curves was above 0.99 in 86.7% of the non cemented cases. Lower values of the final correlation coefficient and deviations in the frequency response pattern were associated with instability or impending bone fracture. In the cases with a partially cemented stem an important difference in frequency response function between the final stage of non cemented trial insertion and the final cemented stage was found in 84.9% of the cases. Furthermore, the frequency response function varied with the degree of cement curing.</p> <p>Conclusion</p> <p>The frequency response function change provides reliable information regarding the stability evolution of the stem-femur system during the insertion. The protocol described in this paper can be used to accurately detect the insertion end point and to reduce the risk for intra-operative fracture.</p
Estimating offsets for avian displacement effects of anthropogenic impacts
Biodiversity offsetting, or compensatory mitigation, is increasingly being used in temperate grassland ecosystems to compensate for unavoidable environmental damage from anthropogenic developments such as transportation infrastructure, urbanization, and energy development. Pursuit of energy independence in the United States will expand domestic energy production. Concurrent with this increased growth is increased disruption to wildlife habitats, including avian displacement from suitable breeding habitat. Recent studies at energy-extraction and energy-generation facilities have provided evidence for behavioral avoidance and thus reduced use of habitat by breeding waterfowl and grassland birds in the vicinity of energy infrastructure. To quantify and compensate for this loss in value of avian breeding habitat, it is necessary to determine a biologically based currency so that the sufficiency of offsets in terms of biological equivalent value can be obtained. We describe a method for quantifying the amount of habitat needed to provide equivalent biological value for avifauna displaced by energy and transportation infrastructure, based on the ability to define five metrics: impact distance, impact area, pre-impact density, percent displacement, and offset density. We calculate percent displacement values for breeding waterfowl and grassland birds and demonstrate the applicability of our avian-impact offset method using examples for wind and oil infrastructure. We also apply our method to an example in which the biological value of the offset habitat is similar to the impacted habitat, based on similarity in habitat type (e.g., native prairie), geographical location, land use, and landscape composition, as well as to an example in which the biological value of the offset habitat is dissimilar to the impacted habitat. We provide a worksheet that informs potential users how to apply our method to their specific developments and a framework for developing decision-support tools aimed at achieving landscape-level conservation goals
An item and construct bias analysis of two language versions of a verbal analogies scale
The Woodcock Muñoz Language Survey is a test of cognitive academic language proficiency that has been adapted from English into Xhosa by a South African team of researchers. This study was primarily concerned with the Verbal Analogies Scale of the Woodcock Muñoz Language Survey and aimed to extend previous research on the equivalence of the two language versions of the scale. The study employed a monolingual two-group design consisting of 150 mainly English-speaking and 149 mainly Xhosa learners in Grades 6 and 7. The first research objective was to investigate item bias (or differential item functioning items) in the Visual Analogies Scale across the Xhosa and English versions using logistic regression and Mantel–Haenszel statistical techniques. Five items were identified as differential item functioning. The second objective was to evaluate the construct equivalence of the two versions by conducting a factor analysis after removing the differential item functioning items from the scale. Two factors were identified. The first factor displayed significant loadings across both language versions. The second factor was stable for the English version but not for the Xhosa version. Results were supported by calculating a Tucker’s phi coefficient for both factors. It was therefore concluded that Factor 1 is structurally equivalent across the two language versions but that Factor 2 was not structurally equivalent. Thus, the detection and removal of differential item functioning items did not result in structural equivalence.Department of HE and Training approved lis
The impact of different DNA extraction kits and laboratories upon the assessment of human gut microbiota composition by 16S rRNA gene sequencing
Peer reviewedPublisher PD
Financial incentives to improve adherence to anti-psychotic maintenance medication in non-adherent patients - a cluster randomised controlled trial (FIAT)
Background
Various interventions have been tested to achieve adherence to anti-psychotic maintenance medication in non-adherent patients with psychotic disorders, and there is no consistent evidence for the effectiveness of any established intervention. The effectiveness of financial incentives in improving adherence to a range of treatments has been demonstrated; no randomised controlled trial however has tested the use of financial incentives to achieve medication adherence for patients with psychotic disorders living in the community.
Methods/Design
In a cluster randomised controlled trial, 34 mental health teams caring for difficult to engage patients in the community will be randomly allocated to either the intervention group, where patients will be offered a financial incentive for each anti-psychotic depot medication they receive over a 12 month period, or the control group, where all patients will receive treatment as usual. We will recruit 136 patients with psychotic disorders who use these services and who have problems adhering to antipsychotic depot medication, although all conventional methods to achieve adherence have been tried. The primary outcome will be adherence levels, and secondary outcomes are global clinical improvement, number of voluntary and involuntary hospital admissions, number of attempted and completed suicides, incidents of physical violence, number of police arrests, number of days spent in work/training/education, subjective quality of life and satisfaction with medication. We will also establish the cost effectiveness of offering financial incentives.
Discussion
The study aims to provide new evidence on the effectiveness and cost effectiveness of offering financial incentives to patients with psychotic disorders to adhere to antipsychotic maintenance medication. If financial incentives improve adherence and lead to better health and social outcomes, they may be recommended as one option to improve the treatment of non-adherent patients with psychotic disorders.
Trial Registration
Current controlled trials ISRCTN77769281
Patients’ Perceptions and Experiences of Familial Hypercholesterolemia, Cascade Genetic Screening and Treatment
Background: Familial hypercholesterolemia (FH) is a serious genetic disorder affecting approximately 1 in every 300 to 500 individuals and is characterised by excessively high low-density lipoprotein (LDL) cholesterol levels, substantially increased risk of early-onset coronary heart disease (CHD) and premature mortality. If FH is untreated, it leads to a greater than 50 % risk of CHD in men by the age of 50 and at least 30 % in women by the age of 60. FH can be diagnosed through genetic screening and effectively managed through pharmacological treatment and lifestyle changes. Purpose: Familial hypercholesterolemia (FH) is a genetic health condition that increases the risk of cardiovascular disease. Although FH can be effectively managed with appropriate pharmacological and dietary interventions, FH detection rate through genetic screening remains low. The present study explored perceptions and experiences of FH patients (N = 18) involved in a genetic cascade screening programme. Methods: Face-to-face interviews were conducted to assess patients’ knowledge and understanding of FH, explore factors linked to adherence to health-protective behaviours and examine perceptions of genetic screening. Results: Thematic analysis of interviews revealed four themes: disease knowledge, severity of FH, lifestyle behavioural change and barriers to cascade screening and treatment. Participants recognised FH as a permanent, genetic condition that increased their risk of CHD and premature mortality. Many participants dismissed the seriousness of FH and the importance of lifestyle changes because they perceived it to be effectively managed through medication. Despite positive attitudes toward screening, many participants reported that relatives were reluctant to attend screening due to their relatives’ ‘fatalistic’ outlook or low motivation. Participants believed that they had insufficient authority or control to persuade family members to attend screening and welcomed greater hospital assistance for contact with relatives. Conclusions: Findings support the adoption of direct methods of recruitment to cascade screening led by medical professionals, who were perceived as having greater authority. Other implications included the need for clinicians to provide clear information, particularly to those who are asymptomatic, related to the seriousness of FH and the necessity for adherence to medication and lifestyle changes
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