5,398 research outputs found
Stopping of protons Improved accuracy of the UCA model
Recent theoretical developments in the unitary convolution approximation UCA for electronic energy losses of bare and screened ions are presented. Examples are given for proton beams and rare gas targets. For gas targets there exists a sufficient amount of experimental data on charge exchange, for pinpointing the largely unknown stopping power contribution of electron capture processes at low and intermediate energie
Protocol for a longitudinal qualitative interview study: maintaining psychological well-being in advanced cancer - what can we learn from patients' and carers' own coping strategies?
IntroductionPeople with advanced cancer and their carers experience stress and uncertainty which affects the quality of life and physical and mental health. This study aims to understand how patients and carers recover or maintain psychological well-being by exploring the strategies employed to self-manage stress and uncertainty.Methods and analysisA longitudinal qualitative interview approach with 30 patients with advanced cancer and 30 associated family or informal carers allows the exploration of contexts, mechanisms and outcomes at an individual level. Two interviews, 4â12?weeks apart, will not only enable the exploration of individualsâ evolving coping strategies in response to changing contexts but also how patientsâ and carersâ strategies inter-relate. Patient and Carer focus groups will then consider how the findings may be used in developing an intervention. Recruiting through two major tertiary cancer centres in the North West and using deliberately broad and inclusive criteria will enable the sample to capture demographic and experiential breadth.Ethics and disseminationThe research team will draw on their considerable experience to ensure that the study is sensitive to a patient and carer group, which may be considered vulnerable but still values being able to contribute its views. Public and patient involvement (PPI) is integral to the design and is evidenced by: a research advisory group incorporating patient and carers, prestudy consultations with the PPI group at one of the study sites and a user as the named applicant. The study team will use multiple methods to disseminate the findings to clinical, policy and academic audiences. A key element will be engaging health professionals in patient and carer ideas for promoting self-management of psychological well-being. The study has ethical approval from the North West Research Ethics Committee and the appropriate NHS governance clearance.RegistrationNational Institute for Health Research (NIHR) Clinical Studies Portfolio, UK Clinical Research Network (UKCRN) Study number 11725
Impact parameter dependence of the electronic energy loss of fast cluster projectiles
Electronic energy loss of molecular clusters as a function of impact parameter is less understood than atomic energy loss. Vicinage effects due to mutual interference between cluster fragments play a key role in the determination of the cluster electronic energy loss. In this work, we describe a molecular extension of the perturbative convolution approximation PCA energy loss model, namely MPCA molecular PCA , which yields remarkable agreement with first order Born semiclassical approximation SCA results. The physical inputs of the model are the oscillators strengths of the target atoms and the projectile electron density. A very good agreement is obtained with time consuming full first order calculations for bare incident molecular clusters for several angles between cluster axis and velocity directio
Impact of a hospice rapid response service on preferred place of death, and costs
Background: Many people with a terminal illness would prefer to die at home. A new palliative rapid response service (RRS) provided by a large hospice provider in South East England was evaluated (2010) to provide evidence of impact on achieving preferred place of death and costs. The RRS was delivered by a team of trained health care assistants and available 24/7. The purpose of this study was to (i) compare the characteristics of RRS users and non-users, (ii) explore differences in the proportions of users and non-users dying in the place of their choice, (iii) monitor the whole system service utilisation of users and non-users, and compare costs. Methods: All hospice patients who died with a preferred place of death recorded during an 18 month period were included. Data (demographic, preferences for place of death) were obtained from hospice records. Dying in preferred place was modelled using stepwise logistic regression analysis. Service use data (period between referral to hospice and death) were obtained from general practitioners, community providers, hospitals, social services, hospice, and costs calculated using validated national tariffs. Results: Of 688 patients referred to the hospice when the RRS was operational, 247 (35.9 %) used it. Higher proportions of RRS users than non-users lived in their own homes with a co-resident carer (40.3 % vs. 23.7 %); more non-users lived alone or in residential care (58.8 % vs. 76.3 %). Chances of dying in the preferred place were enhanced 2.1 times by being a RRS user, compared to a non-user, and 1.5 times by having a co-resident carer, compared to living at home alone or in a care home. Total service costs did not differ between users and non-users, except when referred to hospice very close to death (users had higher costs). Conclusions: Use of the RRS was associated with increased likelihood of dying in the preferred place. The RRS is cost neutral
The operationalized psychodynamic diagnostics system. Clinical relevance, reliability and validity
In this paper, we present a multiaxial system for psychodynamic diagnosis, which has attained wide usage in Germany in the last 10 years. First we will discuss the 4 operationalized psychodynamic diagnostics (OPD) axes: illness experience and treatment assumptions, relationships, mental conflicts, and structure, then clinical applications will be outlined. Focus psychodynamic formulations can be employed both with inpatients and with outpatients. Studies show good reliability in a research context and acceptable reliability for clinical purposes. Validity will be separately summarized as content, criterion, and construct validity. Validity studies indicate good validity for the individual axes. Numerous studies on the OPD indicate areas of possible improvement, for example for clinical purposes the OPD should be more practically formulated
Variable cavity volume tooling for high-performance resin infusion moulding
This article describes the research carried out by Warwick under the BAE Systems/EPSRC programme âFlapless Aerial Vehicles Integrated Interdisciplinary Research â FLAVIIRâ. Warwick's aim in FLAVIIR was to develop low-cost innovative tooling technologies to enable the affordable manufacture of complex composite aerospace structures and to help realize the aim of the Grand Challenge of maintenance-free, low-cost unmanned aerial vehicle manufacture. This article focuses on the evaluation of a novel tooling process (variable cavity tooling) to enable the complete infusion of resin throughout non-crimp fabric within a mould cavity under low (0.1 MPa) injection pressure. The contribution of the primary processing parameters to the mechanical properties of a carbon composite component (bulk-head lug section), and the interactions between parameters, was determined. The initial mould gap (di) was identified as having the most significant effect on all measured mechanical properties, but complex interactions between di, n (number of fabric layers), and vc (mould closure rate) were observed. The process capability was low due to the manual processing, but was improved through process optimization, and delivered properties comparable to high-pressure resin transfer moulding
Influence of production batch related parameters on static and fatigue resistance of LPBF produced AlSi7Mg0.6
In laser powder bed fusion (LPBF), the influence material properties are often determined as a function of the inclination with respect to the build direction. In industrial production with variable component shapes and dimensions, the part orientation will often be a matter of the available space in the build volume. Additionally, build-to-build variability is an important factor that may impact the mechanical properties that are often not quantified. Such sources of variability are of great importance for highly demanding sectors such as aviation and aerospace, where lightweight Al-alloys are often used with the geometrical freedom given by the LPBF process. Hence, this work systematically investigates the influence of production batch-related parameters together with part inclination in the LPBF of AlSi7Mg0.6 alloy. Three builds were executed to quantify the impact of the batch, part position, and inclination on the static and fatigue resistance of the alloy in a completely randomized experimental design using an industrial LPBF machine. The results were analysed by the appropriate statistical methods both for discrete and functional data. The results showed that while the part orientation only influenced the static properties, the part position significantly affected the fatigue life demonstrated by the different low cycle fatigue life coefficients
Graphene-based perfect optical absorbers harnessing guided mode resonances
We numerically and experimentally investigate graphene-based optical
absorbers that exploit guided mode resonances (GMRs) achieving perfect
absorption over a bandwidth of few nanometers (over the visible and
near-infrared ranges) with a 40-fold increase of the monolayer graphene
absorption. We analyze the influence of the geometrical parameters on the
absorption rate and the angular response for oblique incidence. Finally, we
experimentally verify the theoretical predictions in a one-dimensional,
dielectric grating and placing it near either a metallic or a dielectric
mirror
Graphene-based absorber exploiting guided mode resonances in one-dimensional gratings
A one-dimensional dielectric grating, based on a simple geometry, is proposed
and investigated to enhance light absorption in a monolayer graphene exploiting
guided mode resonances. Numerical findings reveal that the optimized
configuration is able to absorb up to 60% of the impinging light at normal
incidence for both TE and TM polarizations resulting in a theoretical
enhancement factor of about 26 with respect to the monolayer graphene
absorption (about 2.3%). Experimental results confirm this behaviour showing
CVD graphene absorbance peaks up to about 40% over narrow bands of few
nanometers. The simple and flexible design paves the way for the realization of
innovative, scalable and easy-to-fabricate graphene-based optical absorbers
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