831 research outputs found
System-adapted correlation energy density functionals from effective pair interactions
We present and discuss some ideas concerning an ``average-pair-density
functional theory'', in which the ground-state energy of a many-electron system
is rewritten as a functional of the spherically and system-averaged pair
density. These ideas are further clarified with simple physical examples. We
then show that the proposed formalism can be combined with density functional
theory to build system-adapted correlation energy functionals. A simple
approximation for the unknown effective electron-electron interaction that
enters in this combined approach is described, and results for the He series
and for the uniform electron gas are briefly reviewed.Comment: to appear in Phil. Mag. as part of Conference proceedings for the
"Electron Correlations and Materials Properties", Kos Greece, July 5-9, 200
External validation of a multivariable claims-based rule for predicting in-hospital mortality and 30-day post-pulmonary embolism complications
Recommended from our members
Variation in the use of chemotherapy in lung cancer
Factors influencing the use of chemotherapy for the initial (6 months) treatment of lung cancer in South East England were investigated. The variables explored as possibly influencing the use of chemotherapy were sex, age, the year of diagnosis, the type of lung cancer, the stage, the index of multiple deprivation and the cancer network of residence. χ2 analysis and multivariate logistic regression models were used to examine the effect of each of the variables on the use of chemotherapy. The results showed a highly significant trend in use of chemotherapy over time; the adjusted proportion of patients receiving chemotherapy increasing from 13.6% in 1994 to 29.3% in 2003. However, age, cancer network and type of lung cancer had the strongest influence on the use of chemotherapy. This finding is important when we consider that the NHS Cancer Plan aims at improving inequalities in cancer care in the UK
Three-dimensional jamming and flows of soft glassy materials
Various disordered dense systems such as foams, gels, emulsions and colloidal
suspensions, exhibit a jamming transition from a liquid state (they flow) to a
solid state below a yield stress. Their structure, thoroughly studied with
powerful means of 3D characterization, exhibits some analogy with that of
glasses which led to call them soft glassy materials. However, despite its
importance for geophysical and industrial applications, their rheological
behavior, and its microscopic origin, is still poorly known, in particular
because of its nonlinear nature. Here we show from two original experiments
that a simple 3D continuum description of the behaviour of soft glassy
materials can be built. We first show that when a flow is imposed in some
direction there is no yield resistance to a secondary flow: these systems are
always unjammed simultaneously in all directions of space. The 3D jamming
criterion appears to be the plasticity criterion encountered in most solids. We
also find that they behave as simple liquids in the direction orthogonal to
that of the main flow; their viscosity is inversely proportional to the main
flow shear rate, as a signature of shear-induced structural relaxation, in
close similarity with the structural relaxations driven by temperature and
density in other glassy systems.Comment: http://www.nature.com/nmat/journal/v9/n2/abs/nmat2615.htm
Validation of the care transition measure in multi-ethnic South-East Asia in Singapore
10.1186/1472-6963-12-256BMC Health Services Research121
Unintended Consequences of Incentive Provision for Behaviour Change and Maintenance around Childbirth
Financial (positive or negative) and non-financial incentives or rewards are increasingly used in attempts to influence health behaviours. While unintended consequences of incentive provision are discussed in the literature, evidence syntheses did not identify any primary research with the aim of investigating unintended consequences of incentive interventions for lifestyle behaviour change. Our objective was to investigate perceived positive and negative unintended consequences of incentive provision for a shortlist of seven promising incentive strategies for smoking cessation in pregnancy and breastfeeding. A multi-disciplinary, mixed-methods approach included involving two service-user mother and baby groups from disadvantaged areas with experience of the target behaviours as study co-investigators. Systematic reviews informed the shortlist of incentive strategies. Qualitative semi-structured interviews and a web-based survey of health professionals asked open questions on positive and negative consequences of incentives. The participants from three UK regions were a diverse sample with and without direct experience of incentive interventions: 88 pregnant women/recent mothers/partners/family members; 53 service providers; 24 experts/decision makers and interactive discussions with 63 conference attendees. Maternity and early years health professionals (n = 497) including doctors, midwives, health visitors, public health and related staff participated in the survey. Qualitative analysis identified ethical, political, cultural, social and psychological implications of incentive delivery at population and individual levels. Four key themes emerged: how incentives can address or create inequalities; enhance or diminish intrinsic motivation and wellbeing; have a positive or negative effect on relationships with others within personal networks or health providers; and can impact on health systems and resources by raising awareness and directing service delivery, but may be detrimental to other health care areas. Financial incentives are controversial and generated emotive and oppositional responses. The planning, design and delivery of future incentive interventions should evaluate unexpected consequences to inform the evidence for effectiveness, cost-effectiveness and future implementation
Survival trends for small intestinal cancer in England and Wales, 1971–1990: national population-based study
This population-based study examines prognostic factors and survival trends among adults (15–99 years) diagnosed with small intestinal cancer in England and Wales during 1971–1990 and followed up to 1995. During this period, the 1- and 5-year age-standardised relative survival rates for small intestinal cancers combined were 42% and 23%, respectively. Duodenal tumours, adenocarcinomas, men, patients with advanced age and the most deprived patients had the poorest prognosis. For all small bowel tumours combined, the excess risk of death fell significantly by 6–9% every 4 years over the 20-year period (adjusted excess hazard ratio (EHR) 0.91 at 1 year after diagnosis, 0.94 at 5 years). For duodenal tumours, the EHR fell by about 14% (95% CI 5–22%) every 4 years between 1979 and 1990, and a similar trend for jejunal tumours was of borderline significance. Further population-based investigations linking survival data to individual data on diagnostic methods and types of treatment are needed
A novel isolator-based system promotes viability of human embryos during laboratory processing
In vitro fertilisation (IVF) and related technologies are arguably the most challenging of all cell culture applications. The starting material is a single cell from which one aims to produce an embryo capable of establishing a pregnancy eventually leading to a live birth. Laboratory processing during IVF treatment requires open manipulations of gametes and embryos, which typically involves exposure to ambient conditions. To reduce the risk of cellular stress, we have developed a totally enclosed system of interlinked isolator-based workstations designed to maintain oocytes and embryos in a physiological environment throughout the IVF process. Comparison of clinical and laboratory data before and after the introduction of the new system revealed that significantly more embryos developed to the blastocyst stage in the enclosed isolator-based system compared with conventional open-fronted laminar flow hoods. Moreover, blastocysts produced in the isolator-based system contained significantly more cells and their development was accelerated. Consistent with this, the introduction of the enclosed system was accompanied by a significant increase in the clinical pregnancy rate and in the proportion of embryos implanting following transfer to the uterus. The data indicate that protection from ambient conditions promotes improved development of human embryos. Importantly, we found that it was entirely feasible to conduct all IVF-related procedures in the isolator-based workstations
Treating tobacco dependence in older adults: a survey of primary care clinicians’ knowledge, attitudes, and practice
BACKGROUND: The benefits of smoking cessation among older people are well documented. Despite this, evidence suggests that older smokers are rarely engaged in smoking cessation efforts, and that existing tobacco dependence treatments require further tailoring to the specific needs of older smokers. This study assesses the knowledge, attitudes, and clinical practice of primary care clinicians in relation to addressing tobacco dependence among older people.
METHODS: A cross-sectional survey of 427 NHS primary care clinicians in a large English city was conducted using modified version of a previously validated questionnaire.
RESULTS: One hundred and seventy one clinicians (40 % response rate) completed the survey. While the majority (90.0 %) of respondents reported enquiring regularly about older patients’ smoking status, just over half (59.1 %) reported providing older patients with smoking cessation support. A lack of awareness in relation to the prevalence and impact of smoking in later life were apparent: e.g. only 47 % of respondents were aware of that approximately 10 life years are lost due to smoking related disease, and only 59 % knew that smoking can reduce the effectiveness of medication prescribed for conditions common in later life. Self-reported attendance at smoking-related training was significantly associated with proactive clinical practice.
CONCLUSIONS: There is a need to improve clinicians’ knowledge, in relation to smoking and smoking cessation in older patients and to build clinician confidence in seizing teachable moments. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12875-015-0317-7) contains supplementary material, which is available to authorized users
Weinberg like sum rules revisited
The generalized Weinberg sum rules containing the difference of isovector
vector and axial-vector spectral functions saturated by both finite and
infinite number of narrow resonances are considered. We summarize the status of
these sum rules and analyze their overall agreement with phenomenological
Lagrangians, low-energy relations, parity doubling, hadron string models, and
experimental data.Comment: 31 pages, noticed misprints are corrected, references are added, and
other minor corrections are mad
- …