Gravitational Instabilities in a proto-solar like disc I.: Dynamics and Chemistry

To date, most simulations of the chemistry in protoplanetary discs have used 1 + 1D or 2D axisymmetric α-disc models to determine chemical compositions within young systems. This assumption is inappropriate for non-axisymmetric, gravitationally unstable discs, which may be a significant stage in early protoplanetary disc evolution. Using 3D radiative hydrodynamics, we have modelled the physical and chemical evolution of a 0.17 M⊙ self-gravitating disc over a period of 2000 yr. The 0.8 M⊙ central protostar is likely to evolve into a solar-like star, and hence this Class 0 or early Class I young stellar object may be analogous to our early Solar system. Shocks driven by gravitational instabilities enhance the desorption rates, which dominate the changes in gas-phase fractional abundances for most species. We find that at the end of the simulation, a number of species distinctly trace the spiral structure of our relatively low-mass disc, particularly CN. We compare our simulation to that of a more massive disc, and conclude that mass differences between gravitationally unstable discs may not have a strong impact on the chemical composition. We find that over the duration of our simulation, successive shock heating has a permanent effect on the abundances of HNO, CN and NH3, which may have significant implications for both simulations and observations. We also find that HCO+ may be a useful tracer of disc mass. We conclude that gravitational instabilities induced in lower mass discs can significantly, and permanently, affect the chemical evolution, and that observations with high-resolution instruments such as Atacama Large Millimeter/submillimeter Array (ALMA) offer a promising means of characterizing gravitational instabilities in protosolar discs

STARBENCH: the D-type expansion of an HII region

STARBENCH is a project focused on benchmarking and validating different star formation and stellar feedback codes. In this first STARBENCH paper we perform a comparison study of the D-type expansion of an H II region. The aim of this work is to understand the differences observed between the 12 participating numerical codes against the various analytical expressions examining the D-type phase of H II region expansion. To do this, we propose two well-defined tests which are tackled by 1D and 3D grid- and smoothed particle hydrodynamics-based codes. The first test examines the ‘early phase’ D-type scenario during which the mechanical pressure driving the expansion is significantly larger than the thermal pressure of the neutral medium. The second test examines the ‘late phase’ D-type scenario during which the system relaxes to pressure equilibrium with the external medium. Although they are mutually in excellent agreement, all 12 participating codes follow a modified expansion law that deviates significantly from the classical Spitzer solution in both scenarios. We present a semi-empirical formula combining the two different solutions appropriate to both early and late phases that agrees with high-resolution simulations to ≲ 2 per cent. This formula provides a much better benchmark solution for code validation than the Spitzer solution. The present comparison has validated the participating codes and through this project we provide a data set for calibrating the treatment of ionizing radiation hydrodynamics codes

Patient satisfaction in neurological second opinions and tertiary referrals

Although the number of neurological second opinions (SOs) and tertiary referrals (TRs) is increasing, only little is known about expectations and patient satisfaction in this group of patients. Therefore, the purpose of this study was to explore expectations of patients who get a neurological SO or TR and to assess patient satisfaction in these groups of patients. All new patients attending an academic neurological day-care clinic in a 6-month period were investigated. Demographic characteristics, duration of symptoms, expectations and motivation, new diagnoses and treatment consequences were studied, and patient satisfaction with the previous physician and the day-care clinic physician was assessed. Three hundred consecutive patients (183 SOs and 117 TRs) were evaluated. SO patients were younger (47 years vs. 51 years), and their duration of symptoms was longer (24 vs. 13 months) than TR patients. Most patients expected a new diagnosis or treatment (60%). SO patients were equally as satisfied with the day-care clinic consultation as TR patients (overall satisfaction using a VAS-score ranging 0–10: 7.4 vs. 7.5; p = 0.81), and significantly less satisfied with the referring physician (overall satisfaction: 5.6 vs. 7.0; p < 0.001). SO patients, in particular, were more satisfied with the degree of information and emotional support provided by the consulting neurologist as compared to the referring physician. Receiving a new diagnosis and/or treatment advice did not influence satisfaction. A day-care admission for neurological SO and TR leads to an increase of patient satisfaction, irrespective of making a new diagnosis or initiation of a new treatment

Understanding the explanatory model of the patient on their medically unexplained symptoms and its implication on treatment development research: a Sri Lanka Study

<p>Abstract</p> <p>Background</p> <p>Patients with medically unexplained symptoms (MUS) are often distressed, disabled and dissatisfied with the care they receive. Illness beliefs held by patients have a major influence on the decision to consult, persistence of symptoms and the degree of disability. Illness perception models consist of frameworks to organise information from multiple sources into distinct but interrelated dimensions: identity (the illness label), cause, consequences, emotional representations perceived control and timeline.</p> <p>Our aim was to elicit the illness perceptions of patients with MUS in Sri Lankan primary care to modify and improve a CBT intervention.</p> <p>Method</p> <p>An intervention study was conducted in a hospital primary care clinic in Colombo, Sri Lanka using CBT for MUS. As a part of the baseline assessment, qualitative data was collected using; the Short Explanatory Model Interview (SEMI), from 68 patients (16–65 years) with MUS. We categorised the qualitative data in to key components of the illness perception model, to refine CBT intervention for a subsequent larger trial study.</p> <p>Results</p> <p>The cohort was chronically ill and 87% of the patients were ill for more than six months (range six months to 20 years) with 5 or more symptoms and 6 or more visits over preceding six months. A majority were unable to offer an explanation on identity (59%) or the cause (56%), but in the consequence domain 95% expressed significant illness worries; 37% believed their symptoms indicated moderately serious illness and 58% very serious illness. Reflecting emotional representation, 33% reported fear of death, 20% fear of paralysis, 13% fear of developing cancer and the rest unspecified incurable illness. Consequence and emotional domains were significant determinants of distress and consultations. Their repeated visits were to seek help to alleviate symptoms. Only a minority expected investigations (8.8 %) or diagnosis (8.8%). However, the doctors who had previously treated them allegedly concentrated more on identity than cause. The above information was used to develop simple techniques incorporating analogies to alter their perceptions</p> <p>Conclusion</p> <p>The illness perception model is useful in understanding the continued distress of patients with persistent symptoms without an underlying organic cause. Hence it can make a significant contribution when developing and evaluating culturally sensitive patient friendly interventions.</p

A European research agenda for somatic symptom disorders, bodily distress disorders, and functional disorders: Results of an estimate-talk-estimate delphi expert study

Background: Somatic Symptom Disorders (SSD), Bodily Distress Disorders (BDD) and functional disorders (FD) are associated with high medical and societal costs and pose a substantial challenge to the population and health policy of Europe. To meet this challenge, a specific research agenda is needed as one of the cornerstones of sustainable mental health research and health policy for SSD, BDD, and FD in Europe. Aim: To identify the main challenges and research priorities concerning SSD, BDD, and FD from a European perspective. Methods: Delphi study conducted from July 2016 until October 2017 in 3 rounds with 3 workshop meetings and 3 online surveys, involving 75 experts and 21 European countries. EURONET-SOMA and the European Association of Psychosomatic Medicine (EAPM) hosted the meetings. Results: Eight research priorities were identified: (1) Assessment of diagnostic profiles relevant to course and treatment outcome. (2) Development and evaluation of new, effective interventions. (3) Validation studies on questionnaires or semi-structured interviews that assess chronic medical conditions in this context. (4) Research into patients preferences for diagnosis and treatment. (5) Development of new methodologic designs to identify and explore mediators and moderators of clinical course and treatment outcomes (6). Translational research exploring how psychological and somatic symptoms develop from somatic conditions and biological and behavioral pathogenic factors. (7) Development of new, effective interventions to personalize treatment. (8) Implementation studies of treatment interventions in different settings, such as primary care, occupational care, general hospital and specialty mental health settings. The general public and policymakers will benefit from the development of new, effective, personalized interventions for SSD, BDD, and FD, that will be enhanced by translational research, as well as from the outcomes of research into patient involvement, GP-patient communication, consultation-liaison models and implementation. Conclusion: Funding for this research agenda, targeting these challenges in coordinated research networks such as EURONET-SOMA and EAPM, and systematically allocating resources by policymakers to this critical area in mental and physical well-being is urgently needed to improve efficacy and impact for diagnosis and treatment of SSD, BDD, and FD across Europe

“Medically unexplained” symptoms and symptom disorders in primary care: prognosis-based recognition and classification

Background: Many patients consult their GP because they experience bodily symptoms. In a substantial proportion of cases, the clinical picture does not meet the existing diagnostic criteria for diseases or disorders. This may be because symptoms are recent and evolving or because symptoms are persistent but, either by their character or the negative results of clinical investigation cannot be attributed to disease: so-called “medically unexplained symptoms” (MUS). MUS are inconsistently recognised, diagnosed and managed in primary care. The specialist classification systems for MUS pose several problems in a primary care setting. The systems generally require great certainty about presence or absence of physical disease, they tend to be mind-body dualistic, and they view symptoms from a narrow specialty determined perspective. We need a new classification of MUS in primary care; a classification that better supports clinical decision-making, creates clearer communication and provides scientific underpinning of research to ensure effective interventions. Discussion: We propose a classification of symptoms that places greater emphasis on prognostic factors. Prognosis-based classification aims to categorise the patient’s risk of ongoing symptoms, complications, increased healthcare use or disability because of the symptoms. Current evidence suggests several factors which may be used: symptom characteristics such as: number, multi-system pattern, frequency, severity. Other factors are: concurrent mental disorders, psychological features and demographic data. We discuss how these characteristics may be used to classify symptoms into three groups: self-limiting symptoms, recurrent and persistent symptoms, and symptom disorders. The middle group is especially relevant in primary care; as these patients generally have reduced quality of life but often go unrecognised and are at risk of iatrogenic harm. The presented characteristics do not contain immediately obvious cut-points, and the assessment of prognosis depends on a combination of several factors. Conclusion: Three criteria (multiple symptoms, multiple systems, multiple times) may support the classification into good, intermediate and poor prognosis when dealing with symptoms in primary care. The proposed new classification specifically targets the patient population in primary care and may provide a rational framework for decision-making in clinical practice and for epidemiologic and clinical research of symptoms

Functional illness in primary care: dysfunction versus disease

<p>Abstract</p> <p>Background</p> <p>The Biopsychosocial Model aims to integrate the biological, psychological and social components of illness, but integration is difficult in practice, particularly when patients consult with medically unexplained physical symptoms or functional illness.</p> <p>Discussion</p> <p>This Biopsychosocial Model was developed from General Systems Theory, which describes nature as a dynamic order of interacting parts and processes, from molecular to societal. Despite such conceptual progress, the biological, psychological, social and spiritual components of illness are seldom managed as an integrated whole in conventional medical practice. This is because the biomedical model can be easier to use, clinicians often have difficulty relinquishing a disease-centred approach to diagnosis, and either dismiss illness when pathology has been excluded, or explain all undifferentiated illness in terms of psychosocial factors. By contrast, traditional and complementary treatment systems describe reversible functional disturbances, and appear better at integrating the different components of illness. Conventional medicine retains the advantage of scientific method and an expanding evidence base, but needs to more effectively integrate psychosocial factors into assessment and management, notably of 'functional' illness. As an aid to integration, pathology characterised by structural change in tissues and organs is contrasted with dysfunction arising from disordered physiology or psychology that may occur independent of pathological change.</p> <p>Summary</p> <p>We propose a classification of illness that includes orthogonal dimensions of pathology and dysfunction to support a broadly based clinical approach to patients; adoption of which may lead to fewer inappropriate investigations and secondary care referrals and greater use of cognitive behavioural techniques, particularly when managing functional illness.</p

Risk factors for moderate and severe persistent pain in patients undergoing total knee and hip arthroplasty : a prospective predictive study

Persistent post-surgical pain (PPSP) is a major clinical problem with significant individual, social and health care costs. The aim of this study was to examine the joint role of demographic, clinical and psychological risk factors in the development of moderate and severe PPSP after Total Knee and Hip Arthroplasty (TKA and THA, respectively). This was a prospective study wherein a consecutive sample of 92 patients were assessed 24 hours before (T1), 48 hours after (T2) and 4-6 months (T3) after surgery. Hierarchical logistic regression analyses were performed to identify predictors of moderate and severe levels of PPSP. Four to six months after TKA and THA, 54 patients (58.7%) reported none or mild pain (Numerical Rating Scale: NRS 3). In the final multivariate hierarchical logistic regression analyses, illness representations concerning the condition leading to surgery (osteoarthritis), such as a chronic timeline perception of the disease, emerged as a significant predictor of PPSP. Additionally, post-surgical anxiety also showed a predictive role in the development of PPSP. Pre-surgical pain was the most significant clinical predictive factor and, as expected, undergoing TKA was associated with greater odds of PPSP development than THA. The findings on PPSP predictors after major joint arthroplasties can guide clinical practice in terms of considering cognitive and emotional factors, together with clinical factors, in planning acute pain management before and after surgery.This work was supported by a Project grant (PTDC/SAU-NEU/108557/2008) and by a PhD grant (SFRH/BD/36368/2007) from the Portuguese Foundation of Science and Technology, COMPETE and FEDER. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript