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Accuracy of hybrid functionals with non-self-consistent Kohn-Sham orbitals for predicting the properties of semiconductors
No full textAccurately modeling the electronic structure of materials is a persistent challenge to high-throughput screening. A promising means of balancing accuracy against computational cost are non-self-consistent calculations with hybrid density-functional theory, where the electronic band energies are evaluated using a hybrid functional from orbitals obtained with a less demanding (semi-)local functional. We have quantified the performance of this technique for predicting the physical properties of sixteen tetrahedral semiconductors with bandgaps from 0.2-5.5 eV. Provided the base functional predicts a non-metallic electronic structure, bandgaps within 5 % of the PBE0 and HSE06 gaps can be obtained with an order of magnitude reduction in computing time. The positions of the valence and conduction band extrema and the Fermi level are well reproduced, further enabling calculation of the band dispersion, density of states, and dielectric properties using Fermi’s Golden Rule. While the error in the non-self-consistent total energies is ~50 meV atom-1, the energy-volume curves are reproduced accurately enough to obtain the equilibrium volume and bulk modulus with minimal error. We also test the dielectric-dependent scPBE0 functional and obtain bandgaps and dielectric constants to within 2.5 % of the self-consistent results, which amount to a significant improvement over self-consistent PBE0 for a similar computational cost. We identify cases where the non-self-consistent approach is expected to perform poorly, and demonstrate that partial self-consistency provides a practical and efficient workaround. Finally, we perform proof-of-concept calculations on CoO and NiO to demonstrate the applicability of the technique to strongly-correlated open-shell transition-metal oxides
Ethnic, religious and gender differences in intragenerational economic mobility in England and Wales
No full textThis study uses data from consecutive England and Wales censuses to examine the intra-generational economic mobility of individuals with different ethnicities, religions and genders between 1971 and 2011, over time and across cohorts. The findings suggest more downward and less upward mobility among Black Caribbean, Indian Sikh and Muslim people with Bangladeshi, Indian and Pakistani ethnicities, relative to white British groups, and more positive relative progress among Indian Hindu people, but also some variation in the experiences of social mobility between individuals even in the same ethnic groups. For some groups, those becoming adults or migrating to the UK since 1971 occupy an improved position compared with older or longer resident people, but this is not universal. Findings suggest that these persistent inequalities will only be effectively addressed with attention to the structural factors which disadvantage particular ethnic and religious groups, and the specific ways in which these affect women.<br/
How is the behaviour change technique content of the NHS Diabetes Prevention Programme understood by participants? A qualitative study of fidelity, with a focus on receipt
No full textBackground:The National Health Service (NHS) Diabetes Prevention Programme (DPP) is a nationally implemented behavioural intervention for adults at high risk of developing Type 2 diabetes in England, based on a programme specification that stipulates inclusion of nineteen specific behaviour change techniques (BCTs). Previous work has identified drift in fidelity from these NHS England specifications through providers’ programme manuals, training, and delivery, especially in relation to BCTs targeting self-regulatory processes.Purpose: This qualitative study investigates intervention receipt, i.e how the self-regulatory BCT content of the NHS-DPP is understood by participants.Methods: Twenty participants from eight NHS-DPP locations were interviewed; topics included participants’ understanding of self-monitoring of behaviour, goal setting, feedback, problem solving, and action planning. Transcripts were analysed thematically using the framework method.Results: There was wide variation in understanding amongst participants for some BCTs, as well as between BCTs. Participants described their understanding of ‘self-monitoring of behaviours’ with ease and valued BCTs focussed on outcomes (weight loss). Some participants learned how to set appropriate behavioural goals. Participants struggled to recall ‘action planning’ or ‘problem solving’ or found these techniques challenging to understand, unless additional support was provided (e.g. through group discussion). Conclusions: Participants’ lack of understanding of some self-regulatory BCTs is consistent with the drift across fidelity domains previously identified from NHS design specifications. Behavioural interventions should build-in necessary support for participants to help them understand some BCTs such as action planning and problem solving. Alternatively, these self-regulatory BCTs may be intrinsically difficult to use for this population.<br/
Antibacterial activity of 2-hydroxyisocaproic acid (HICA) against obligate anaerobic bacterial species associated with periodontal disease
No full textTopical antiseptics are used to assist and further increase the effect of mechanical biofilm eradication and to potentially prevent new biofilm formation in periodontal treatment. This is of importance in treatment-resistant infections with 10% prevalence of all periodontitis cases to avoid the need for antibiotic therapy. The purpose of this study was to evaluate the antimicrobial activity of DL-2-hydroxyisocaproic acid on human pathogenic obligate anaerobic bacteria related to periodontitis. In this study antimicrobial activity of 2-hydroxyisocaproic acid was observed against 14 bacterial reference strains and clinical isolates of obligate anaerobic bacterial species using a microdilution method in 1.25-160 mg/mL concentrations of 2-hydroxyisocaproic acid. The eleven strains of bacteria included in this study are typically associated with periodontal disease; Porphyromonas gingivalis, Fusobacterium nucleatum, Tannerella forsythia, Aggregatibacter actinomycetemcomitans and Parvimonas micra. Three strains of Cutibacterium acnes, normally associated with skin diseases, were tested for comparison. 90% inhibitory concentration was determined at 48 h and minimum bactericidal concentration was determined after 72 h incubation. 2-hydroxyisocaproic acid was bactericidal at ≥ 160 mg/mL for all isolates tested. The reference strain of T. forsythia, and the reference strain and the clinical isolates of C. acnes were the most tolerant ones. The reference strains and clinical isolates of F. nucleatum and A. actinomycetemcomitans were killed at ≥ 40 mg/mL concentration. In conclusion, topical use of 2-hydroxyisocaproic acid could eventually be a well-tolerated and useful method in the therapy of patients with difficult-to-treat periodontal disease or other superficial infections to avoid unnecessary antibiotic use and the emergence of antibiotic resistance
Multi Frequency Multi Bit Amplitude Modulation of Spoof Surface Plasmon Polaritons by Schottky Diode Bridged Interdigital SRRs
No full textMulti-frequency multi-bit programmable amplitude modulation (AM) of spoofsurface plasmon polaritons (SPPs) is realized at millimeter wave frequencieswith interdigital split-ring resonators (SRRs) and In-Ga-Zn-O (IGZO) Schottkydiodes. Periodic SRRs on a metal line guide both SRR mode and spoof SPPmode, the former of which rejects the spoof SPP propagation at the SRRresonant frequencies. To actively modulate the amplitude of spoof SPPs, IGZOSchottky diodes are fabricated in the SRR gaps, which continuously reconfigureSRRs to metallic loops by applying bias. Interdigital gaps aredesigned in SRRs to increase the capacitance, thus red shifting the resonantfrequencies, which significantly broadens the operation bandwidth of multifrequencyAM. Thus, cascading different kinds of interdigital SRRs withSchottky diodes enables multi-frequency multi-bit AM programmable. As ademonstration, a dual-frequency device was fabricated and characterized,which achieved significant multi-bit AM from -12.5 to -6.2 dB at 34.7 GHz andfrom -26 to -8.5 dB at 50 GHz independently and showed programmablecapability
Functional gastrointestinal disorders in inflammatory bowel disease: Time for a paradigm shift?
No full textRecent advances in biological therapies have revolutionalised and redefined treatment targets in inflammatory bowel disease (IBD). There is now a stronger emphasis on achieving the more stringent therapeutic goals of mucosal and histological healing, rather than clinical remission alone. Consequently, the treatment of refractory 'functional' gastrointestinal symptoms, often attributed as the aftermath of previous inflammation, has recently become more prominent in quiescent disease. With further expected advances in anti-inflammatory treatments on the horizon, the burden of such symptoms in quiescent disease, which have been relatively neglected, is set to become an even bigger problem. In this article, we highlight the current state of research and understanding in this field, including recent developments and clinical practice guidelines on the diagnosis and management of functional gastrointestinal symptoms, such as irritable bowel syndrome and functional anorectal and pelvic floor disorders, in patients with quiescent IBD. These disorders are not only highly prevalent in these patients, they are often misdiagnosed, and are difficult to treat, with very few evidence-based therapies. Moreover, they are associated with substantial impairment in quality-of-life, considerable morbidity, and psychological distress. There is therefore an urgent need for a change in emphasis towards earlier recognition, positive diagnosis, and targeted treatment for patients with ongoing functional gastrointestinal symptoms in the absence of active IBD. This article also highlights the need for further research to develop much needed evidence-based therapies
Another benefit of CMR stress testing: detecting the prevalent vulnerable phenotype of unrecognized myocardial infarction
No full textStability and Instability of the MaxWeight Policy
No full textConsider a switched queueing network with general routing among its queues. The MaxWeight policy assigns available service by maximizing the objective function Σj Qjσj among the different feasible service options, where Qj denotes queue size and σj denotes the amount of service to be executed at queue j.MaxWeight is a greedy policy that does not depend on knowledge of arrival rates and is straightforward to implement. These properties, as well as its simple formulation, suggest MaxWeight as a serious candidate for implementation in the setting of switched queueing networks; MaxWeight has been extensively studied in the context of communication networks. However, a fluid model variant of MaxWeight was shown by Andrews–Zhang (2003) not to be maximally stable. Here, we prove that MaxWeight itself is not in general maximally stable. We also prove MaxWeight is maximally stable in a much more restrictive setting, and that a weighted version of MaxWeight, where the weighting depends on the traffic intensity, is always stable
Attitudes towards Risk Reducing Early Salpingectomy with Delayed Oophorectomy for Ovarian Cancer Prevention: a Cohort Study
No full textObjective: To determine risk-reducing-early-salpingectomy-and-delayed-oophorectomy (RRESDO) acceptability and effect of surgical prevention on menopausal sequelae/satisfaction/regret in women at increased ovarian-cancer (OC) risk. Design: Multicentre, cohort, questionnaire-study (IRSCTN:12310993). Setting: United-Kingdom (UK). Population: OC unaffected UK-women ≥18years, at increased OC-risk, with/without previous RRSO, ascertained through specialist familial-cancer/genetic-clinics and BRCA support-groups. Methods: Participants completed a 39-item questionnaire. Baseline characteristics were described using descriptive statistics. Logistic/linear-regression models analysed impact of variables on RRESDO acceptability and health-outcomes. Main Outcomes: RRESDO acceptability, menopausal-sequelae, satisfaction/regret. Results: 346 of 683 participants underwent risk-reducing salpingo-oophorectomy (RRSO) and 337 did not. 69.1% (181/262) premenopausal women who had not undergone RRSO found it acceptable to participate in a research study offering RRESDO. Premenopausal women concerned about sexual-dysfunction were more likely (OR=2.9, 95%CI=1.2-7.7, p=0.025) to find RRESDO acceptable. Women experiencing sexual-dysfunction after premenopausal-RRSO were more likely to find RRESDO acceptable in retrospect (OR=5.3, 95%CI=1.2-27.5, p<0.031). 88.8%(143/161) premenopausal versus 95.2%(80/84) postmenopausal women who underwent RRSO respectively were satisfied with their decision. 9.4%(15/160) premenopausal and 1.2%(1/81) postmenopausal women who underwent RRSO regretted their decision. HRT-uptake in breast-cancer (BC) unaffected premenopausal individuals was 74.1% (80/108). ). HRT-use did not significantly affect satisfaction/regret levels but reduced symptoms of vaginal-dryness (OR=0.4, 95%CI=0.2-0.9, p=0.025). Conclusion: Data show high RRESDO acceptability particularly in women concerned about sexual-dysfunction. Although RRSO satisfaction remains high, regret rates are much higher for premenopausal women than postmenopausal women. HRT-use following premenopausal RRSO does not increase satisfaction and reduces vaginal dryness
Effect of Paper Type and Water Content in Paper on the Partitioning of 2-FAL between Liquid and Paper Insulations
No full textFor nearly four decades 2-furfural (2-FAL) in transformer oil has been used as a chemical marker to indicate the ageing state of transformer paper insulation. Nevertheless, it has always been a challenge to define an acceptable limit for 2-FAL due to issues related to non-uniform temperature distribution in transformers, stability of 2-FAL in oil and its partitioning between liquid and solid insulation. Therefore, transformer users try to combine the laboratory findings, the operational experience and post-mortem analyses together for predicting ageing state of paper insulation through 2-FAL content in oil. Due to increase in the use of ester liquids in transformers, there is a need to investigate the ability to use 2-FAL as a paper ageing indicator for ester based insulation systems. Laboratory ageing studies have shown that 2-FAL is indeed generated in ester based insulation systems. However, there is a lack of understanding related to the partitioning of 2-FAL in ester based insulation systems. This paper studies the partitioning of 2-FAL in synthetic ester based insulation systems and compares to that in mineral oil based insulation systems with the focus on the effect of paper type and water content in paper. Under the investigated conditions the synthetic ester had higher partitioning coefficients (ratio between the 2-FAL content in oil and paper) than the mineral oil. Partitioning coefficients in both oil types decreased with the increase of the water content in paper. However, change in paper type did not significantly affect the partitioning coefficients in this study