On using visibility correlations to probe the HI distribution from the dark ages to the present epoch I: Formalism and the expected signal

Redshifted 21 cm radiation originating from the cosmological distribution of neutral hydrogen (HI) appears as a background radiation in low frequency radio observations. The angular and frequency domain fluctuations in this radiation carry information about cosmological structure formation. We propose that correlations between visibilities measured at different baselines and frequencies in radio-interferometric observations be used to quantify the statistical properties of these fluctuations. This has an inherent advantage over other statistical estimators in that it deals directly with the visibilities which are the primary quantities measured in radio-interferometric observations. Also, the visibility correlation has a very simple relation with power spectrum. We present estimates of the expected signal for nearly the entire post-recombination era, from the dark ages to the present epoch. The epoch of reionization, where the HI has a patchy distribution, has a distinct signature where the signal is determined by the size of the discrete ionized regions. The signal at other epochs, where the HI follows the dark matter, is determined largely by the power spectrum of dark matter fluctuations. The signal is strongest for baselines where the antenna separations are within a few hundred times the wavelength of observation, and an optimal strategy would preferentially sample these baselines. In the frequency domain, for most baselines the visibilities at two different frequencies are uncorrelated beyond \Delta \nu ~ 1 MHz, a signature which in principle would allow the HI signal to be easily distinguished from the continuum sources of contamination.Comment: 12 pages, 9 figures, Accepted to MNRAS; Replaced to match version accepted in MNRA

Nonadherence to psoriasis medication as an outcome of limited coping resources and conflicting goals: findings from a qualitative interview study with people with psoriasis

Background Medication nonadherence is known to limit the effectiveness of available therapies; however, little is known specifically about medication adherence in people with psoriasis. Medicines self‐management can feel onerous to those with dermatological conditions due to the nature of therapies prescribed and many individuals with psoriasis experience additional challenges such as physical and psychological comorbidities that place significant additional demands on individuals and may undermine adherence. Viewing nonadherence to medication as an outcome of limited personal coping resources and conflicting goals may help to explain medication nonadherence. Objectives To explore individuals’ perspectives of their psoriasis, medication and its management. Methods Twenty people with psoriasis were recruited from community samples in England and interviewed in‐depth about their perceptions of their psoriasis, medication, and adherence to medication and self‐management advice. Data were analysed using Framework Analysis. Results Participants reported that adhering to recommended treatment regimens conflicted with the management of the physical and psychological demands of living with psoriasis. Medication usage was viewed as a source of unresolved emotional distress and, for some, resulted in poor self‐reported adherence, which included medication overuse, underuse and rejection of prescribed therapies. Perceived lack of engagement by clinicians with participants’ self‐management difficulties was viewed as an additional source of stress and distress. Conclusions Adhering to medication in psoriasis can be an additional source of considerable emotional distress. We interpreted some episodes of nonadherence to psoriasis medication as rational attempts by individuals to minimize distress and to gain control over their life

Preferências pelas decisões compartilhadas em pacientes com depressão

Neste estudo, analisaram-se os processos psicológicos associados com as preferências dos pacientes com depressão na tomada de decisão sobre seu tratamento psiquiátrico. Participaram 462 pacientes diagnosticados com um transtorno depressivo agudo ou recorrente. A maior parte preferiu assumir um papel colaborativo-passivo ou totalmente passivo. Os resultados não mostraram diferenças significativas entre pacientes em função de sua cronicidade na preferência por tomada de decisões, embora um maior tempo de tratamento tenha sido associado com um estilo mais passivo. O MANCOVA aplicado ao total de participantes, controlando a idade, o nível educativo e o tempo de tratamento, indicou que os pacientes colaborativos e passivos mostraram maior lócus de controle centralizado na confiança no psiquiatra do que os ativos. Constataram-se diferenças de gênero que mostraram nos homens maior lócus de controle interno e reatância psicológica, e, nas mulheres, maior lócus centralizado no aleatório, o lócus centralizado no psiquiatra e uma percepção de menor autoeficácia. Os achados indicam a necessidade de estudar, sob uma perspectiva diferencial, a participação dos pacientes na tomada de decisão de acordo com os processos psicológicos e a repercussão que esta tem na aderência ao tratamento médico.En el presente estudio se analizaron los procesos psicológicos asociados con las preferencias de los pacientes con depresión en la toma de decisión sobre su tratamiento psiquiátrico. Participaron 462 pacientes diagnosticados con un trastorno depresivo agudo o recurrente. La mayor parte prefirió asumir un rol colaborativo-pasivo o totalmente pasivo. Los resultados no mostraron diferencias significativas entre pacientes en función de su cronicidad en la preferencia por la toma de decisiones, aunque un mayor tiempo de tratamiento se asoció con un estilo más pasivo. El MANCOVA aplicado al total de participantes, controlando la edad, el nivel educativo y el tiempo de tratamiento, indicó que los pacientes colaborativos y pasivos mostraron mayor locus de control centrado en la confianza en el psiquiatra que los activos. Se encontraron diferencias de género mostrando en los hombres mayor locus de control interno y reactancia psicológica, y en las mujeres, mayor locus centrado en el azar. Los análisis de regresión indicaron que en el caso de los hombres, la preferencia pasiva por la toma de decisión es explicada por el locus centrado en el psiquiatra. Sin embargo, en las mujeres tuvo mayor peso la edad, seguida del locus centrado en el azar, el locus centrado en el psiquiatra y una percepción de menor autoeficacia. Los hallazgos señalan la necesidad de estudiar desde una perspectiva diferencial la participación de los pacientes en la toma de decisión de acuerdo con los procesos psicológicos, así como la repercusión que esta tiene en la adherencia al tratamiento médico.This study analyzed the role of psychological processes predicting depressed patients’ preferences in clinical decision-making about psychiatric treatment. 462 patients diagnosed with depressive disorders, acute or recurrent, participated in a crosssectional survey. Most participants preferred collaborative-passive or totally passive roles. Results showed no significant differences between acute and recurrent patients in their preference of participation in decision-making, but longer treatment duration was associated with a more passive style. MANCOVA, controlling age, educational level and treatment duration variables, showed that collaborative and passive patients had a greater locus of control focused on their psychiatrist than active patients. Gender differences were found. Men showed greater internal locus of control and psychological reactance, while women showed greater external locus of control focused on chance. Regression analysis indicated that, for men, passive preferred role was explained by external locus centered on their psychiatrist. However, age registered the highest weight for women’ passive decision-making, followed by the locus focused on chance, locus focused on the psychiatrist and lower self-efficacy. Our findings suggest the need to study shared decision-making from a differential perspective that involves psychological processes and the impact of these processes in adherence to medical treatments

The effects of short-term omission of daily medication on the pathophysiology of heart failure

Aims Pharmacological therapies for heart failure (HF) aim to improve congestion, symptoms, and prognosis. Failing to take medication is a potential cause of worsening HF. Characterizing the effects of short-term medication omission could inform the development of better technologies and strategies to detect and interpret the reasons for worsening HF. We examined the effect of planned HF medication omission for 48 h on weight, echocardiograms, transthoracic bio-impedance, and plasma concentrations of NT-proBNP. Methods and results Outpatients with stable HF and an LVEF <45% were assigned to take or omit their HF medication for 48 h in a randomized, crossover trial. Twenty patients (16 men, LVEF 32 ± 9%, median NT-proBNP 962 ng/L) were included. Compared with regular medication, omission led to an increase in NT-proBNP by 99% (from 962 to 1883 ng/L, P < 0.001), systolic blood pressure by 16% (from 131 to 152 mmHg, P < 0.001), and left atrial volume by 21% (from 69 to 80 mL, P = 0.001), and reductions in transthoracic bio-impedance by 10% (from 33 to 30 Σ, P = 0.001) and serum creatinine by 8% (from 135 to 118 µmol/L, P = 0.012). No significant changes in body weight, heart rate, or LVEF were observed. Conclusions The characteristic pattern of response to short-term medication omission is of increasing congestion but, in contrast to the pattern reported for disease progression, with a rise in blood pressure and improved renal function. In stable HF, weight is not a sensitive marker of short-term diuretic omission

Explaining adherence to self-care behaviours amongst adolescents with food allergy: a comparison of the health belief model and the common sense self-regulation model

OBJECTIVES: To identify explanations for adherence to self-care behaviours amongst adolescents with food allergy-induced anaphylaxis using two social cognition models: the health belief model (HBM) and the common sense self-regulation model (CS-SRM). DESIGN: Cross-sectional self-completion questionnaire study to gain initial evidence of the two models' feasibility/effectiveness in explaining adherence in an adolescent food-allergic population. METHODS: Participants aged 13-19 years with a diagnosis of severe food allergy and a prescription of an adrenaline auto-injector were recruited from hospital outpatients. Adherence to self-care behaviours was measured in addition to constructs from the HBM and CS-SRM. RESULTS: One hundred and eighty-eight food-allergic adolescents completed the questionnaire. The HBM, specifically the constructs perceived severity and barriers, accounted for 21% of the explained variance in adherence behaviours. CS-SRM constructs, illness identity, timeline cyclical beliefs and emotional representations explained 25% of the variance. CONCLUSIONS: Both models performed similarly in explaining adherence to self-care behaviours in adolescents with food allergy. Interventions designed to elicit personal barriers to adherence and to address perceptions of severity and the unpredictable nature of symptoms may be more effective in improving adherence to self-care behaviours than current interventions. STATEMENT OF CONTRIBUTION: What is already known on this subject? Patients' poor management of food allergy induced anaphylaxis is commonly attributed to lack of knowledge and ability in using the adrenaline auto-injector. Adherence to recommended preventive self-care behaviours, like allergen avoidance and carrying emergency medication, are rarely assessed. Social Cognition Models (SCMs) have been successfully applied to a number of adherence-related studies in disease conditions such as asthma and diabetes, but have not yet been applied to food allergy induced anaphylaxis. What does this study add? This is the first large-scale quantitative study of adherence behaviours in adolescents with food allergy. This is the first study to apply theoretical models to explain adherence in the adolescent food allergic population. This is the first application of both models to food allergy, and the first to compare the two models' measurement instruments

Primacy of effective communication and its influence on adherence to artemether-lumefantrine treatment for children under five years of age: a qualitative study.

BACKGROUND\ud \ud Prompt access to artemesinin-combination therapy (ACT) is not adequate unless the drug is taken according to treatment guidelines. Adherence to the treatment schedule is important to preserve efficacy of the drug. Although some community based studies have reported fairly high levels of adherence, data on factors influencing adherence to artemether-lumefantrine (AL) treatment schedule remain inadequate. This study was carried-out to explore the provider's instructions to caretakers, caretakers' understanding of the instructions and how that understanding was likely to influence their practice with regard to adhering to AL treatment schedule.\ud \ud METHODS\ud \ud A qualitative study was conducted in five villages in Kilosa district, Tanzania. In-depth interviews were held with providers that included prescribers and dispensers; and caretakers whose children had just received AL treatment. Information was collected on providers' instructions to caretakers regarding dose timing and how to administer AL; and caretakers' understanding of providers' instructions.\ud \ud RESULTS\ud \ud Mismatch was found on providers' instructions as regards to dose timing. Some providers' (dogmatists) instructions were based on strict hourly schedule (conventional) which was likely to lead to administering some doses in awkward hours and completing treatment several hours before the scheduled time. Other providers (pragmatists) based their instruction on the existing circumstances (contextual) which was likely to lead to delays in administering the initial dose with serious treatment outcomes. Findings suggest that, the national treatment guidelines do not provide explicit information on how to address the various scenarios found in the field. A communication gap was also noted in which some important instructions on how to administer the doses were sometimes not provided or were given with false reasons.\ud \ud CONCLUSIONS\ud \ud There is need for a review of the national malaria treatment guidelines to address local context. In the review, emphasis should be put on on-the-job training to address practical problems faced by providers in the course of their work. Further research is needed to determine the implication of completing AL treatment prior to scheduled time

Prospects for obtaining an r-process from Gamma Ray Burst Disk Winds

We discuss the possibility that r-process nucleosynthesis may occur in the winds from gamma ray burst accretion disks. This can happen if the temperature of the disk is sufficiently high that electron antineutrinos are trapped as well as neutrinos. This implies accretion disks with greater than a solar mass per second accretion rate, although lower accretion rates with higher black hole spin parameters may provide viable environments as well. Additionally, the outflow from the disk must either have relatively low entropy, e.g. around s = 10, or the initial acceleration of the wind must be slow enough that it is neutrino and antineutrino capture as opposed to electron and positron capture that sets the electron fraction.Comment: 8 pages, submitted to Nucl. Phys. A as part of the Nuclei in Cosmos 8 proceeding