A physical activity intervention to improve the quality of life of patients with a stoma: a feasibility study

Background We hypothesise that a physical activity (PA) intervention will improve the quality of life (QoL) of people with a stoma. A feasibility study of the intervention and trial parameters is necessary to inform a future main trial. Methods Participants received a weekly PA consultation by telephone, video conferencing, or face-to-face for 12 weeks with a PA instructor who prescribed physical activities and supported participants by addressing stoma-related concerns and using behaviour change techniques. A feasibility study of the intervention and trial parameters was conducted in three UK sites using mixed methods. Results The number of eligible patients consenting to the study was 30 out of 174 (17%). Most participants were female (73%); 73% had an ileostomy and 27% a colostomy; mean time since diagnosis was 6 months. A total of 18 (64%) participants completed pre- (baseline) and post-intervention (follow-up) measures. Results show an improvement on all scales measuring QoL and disease-specific fatigue. The median PA consultation rate per participant was eight sessions. Participants reported completing 75% or more of the prescribed PA each week. Eight stoma-related themes were identified from qualitative interviews: fear of hernia, bending down, fatigue, pain, prolapse, surgical wounds, stoma appliance, and stigma. The intervention appeared to address these issues. Conclusion This feasibility study demonstrated that a novel manualised PA intervention for people with a stoma is safe, feasible, and acceptable, and shows promise for improving outcomes. However, difficulties with recruitment will need to be carefully considered to ensure the success of future studies in this area

Refining value-at-risk estimates using a Bayesian Markov-switching GJR-GARCH copula-EVT model

In this paper, we propose a model for forecasting Value-at-Risk (VaR) using a Bayesian Markov-switching GJR-GARCH(1,1) model with skewed Student’s-t innovation, copula functions and extreme value theory. A Bayesian Markov-switching GJR-GARCH(1,1) model that identifies non-constant volatility over time and allows the GARCH parameters to vary over time following a Markov process, is combined with copula functions and EVT to formulate the Bayesian Markov-switching GJR-GARCH(1,1) copula-EVT VaR model, which is then used to forecast the level of risk on financial asset returns. We further propose a new method for threshold selection in EVT analysis, which we term the hybrid method. Empirical and back-testing results show that the proposed VaR models capture VaR reasonably well in periods of calm and in periods of crisis

Consensus guidelines for the use and interpretation of angiogenesis assays

The formation of new blood vessels, or angiogenesis, is a complex process that plays important roles in growth and development, tissue and organ regeneration, as well as numerous pathological conditions. Angiogenesis undergoes multiple discrete steps that can be individually evaluated and quantified by a large number of bioassays. These independent assessments hold advantages but also have limitations. This article describes in vivo, ex vivo, and in vitro bioassays that are available for the evaluation of angiogenesis and highlights critical aspects that are relevant for their execution and proper interpretation. As such, this collaborative work is the first edition of consensus guidelines on angiogenesis bioassays to serve for current and future reference

New fundamental insights into capacitance modeling of laterally nonuniform MOS devices

In compact transistor modeling for circuit simulation, the capacitances of conventional MOS devices are commonly determined as the derivatives of terminal charges, which in their turn are obtained from the so-called Ward-Dutton charge partitioning scheme. For devices with a laterally nonuniform channel doping profile, however, it is shown in this paper that no terminal charges exist from which the capacitances can be derived. Instead, for such devices, a new model is presented for the capacitances themselves. Furthermore, a method is given to incorporate such a capacitance model into circuit simulators, which are traditionally based on terminal charge models. Comparison with two-dimensional device simulations and a segmentation model shows that for a constant mobility, the new capacitance model provides an accurate description for a MOSFET with a laterally diffused channel doping profile. Through a comparison with high-frequency measurements, the agreement between model and experimental results is discussed

Capacitance modeling of laterally non-uniform MOS devices

In compact transistor modeling for circuit simulation, the capacitances of conventional MOS devices are commonly determined as the derivatives of terminal charges, which on their turn are obtained from the so-called Ward-Dutton charge partitioning scheme (Ward, 1981). For devices with a laterally non-uniform channel doping profile, however, it is shown in this paper that: 1) no terminal charges exist for the description of capacitances. Instead, 2) a model is presented for the capacitances of such devices, including numerical results for a MOS transistor with a laterally diffused channel doping profile. Finally, 3) a method is given to incorporate such a capacitance model in circuit simulators which are traditionally based on terminal charge models

RF distortion characterisation of sub-micron CMOS

\u3cp\u3eDistortion measurements up to 1 GHz ground tone for 3 different sub-micron CMOS technologies with minimum gatelengths down to 0.18 μm comply well with an accurate compact model. Using a new linearity figure of merit measurements are presented, which show that up to 1 GHz a high linearity at practical bias conditions is obtained because the distortion still predominantly originates from the nonlinear IV characteristics.\u3c/p\u3

RF-distortion in deep-submicron CMOS technologies

\u3cp\u3eThe distortion behaviour of MOSFETs is important for RF-applications. In this paper the influence of technology variations (oxide thickness, substrate doping,...) on distortion is investigated using measurements and a recently developed compact MOSFET model. The influence on distortion of technology scaling down to 0.18μm is verified and further scaling according to the ITRS-roadmap is predicted.\u3c/p\u3