Incentivising public transport use for physical activity gain: process evaluation of the COVID-19 disrupted trips4health randomised controlled trial

BACKGROUND

Partnering with a public transport (PT) provider, state government, and local government, the single-blinded randomised controlled trial, trips4health, investigated the impact of PT use incentives on transport-related physical activity (PA) in Tasmania, Australia. The intervention involved 16-weeks of incentives (bus trip credits) for achieving weekly PT use targets, supported by weekly text messages. This study objective was to conduct a process evaluation of the COVID-19 disrupted trips4health study.

METHODS

The Medical Research Council UK's framework for complex public health interventions guided the process evaluation. Participant reach, acceptability, fidelity and feasibility were evaluated. Administrative and post-intervention survey data were analysed descriptively. Semi-structured interviews with intervention participants (n = 7) and PT provider staff (n = 4) were analysed thematically.

RESULTS

Due to COVID-19, trips4health was placed on hold (March 2020) then stopped (May 2020) as social restrictions impacted PT use. At study cessation, 116 participants (approximately one third of target sample) had completed baseline measures, 110 were randomised, and 64 (n = 29 in the intervention group; n = 35 in the control group) completed post-intervention measures. Participants were 18 - 80 years (average 44.5 years) with females (69%) and those with tertiary education (55%) over-represented. The intervention was delivered with high fidelity with 96% of bus trip credits and 99% of behavioural text messages sent as intended. Interviewed PT staff said implementation was highly feasible. Intervention participant acceptability was high with 90% reporting bus trip incentives were helpful and 59% reporting the incentives motivated them to use PT more. From a total of 666 possible bus trip targets, 56% were met with 38% of intervention participants agreeing and 41% disagreeing that 'Meeting the bus trip targets was easy'. Interviews and open-ended survey responses from intervention participants revealed incentives motivated bus use but social (e.g., household member commitments) and systemic (e.g., bus availability) factors made meeting bus trip targets challenging.

CONCLUSIONS

trips4health demonstrated good acceptability and strong fidelity and feasibility. Future intervention studies incentivising PT use will need to ensure a broader demographic is reached and include more supports to meet PT targets.

TRIAL REGISTRATION

ACTRN12619001136190 .

Identity integration in people with acquired disabilities: A qualitative study

OBJECTIVE

This qualitative investigation focused on identity integration in a sample of individuals who acquired physical disabilities in adulthood. It also argues for the importance and ethics of these methods in the broader field of scholarship on personality change following adversity.

METHOD

Thirteen adults participated in the study. Participants engaged in an expanded Life Story Interview wherein they narrated the story of their life, including a section devoted to their story of acquiring a physical disability. In addition, participants completed questionnaires concerning their psychological well-being and maturity.

RESULTS

We identified two dimensions of narrative themes participants used in grappling with identity integration: one represented active processing of one's life experiences and the other represented the extent to which participants described their identity as wholly transformed by the experience of acquiring a disability. When overlaid, these dimensions yielded four narrative strategies titled: Adapters, Wanderers, Drifters, and Resisters. We also observed that Adapters seemed to have better psychological well-being and maturity than the other groups.

CONCLUSIONS

This study offers a foundation for future scholarship on identity among people with disabilities. It also describes the contexts in which retrospective, qualitative methods are especially appropriate for research on personality change following adversity.

Early or delayed anterior cruciate ligament reconstruction: Is one superior? A systematic review and meta-analysis

Background

Anterior cruciate ligament (ACL) reconstruction is a rapidly developing orthopaedic field and an area of notable clinical equipoise. The optimal timing of surgery in an acute (< 3 weeks) or delayed (≥ 3 weeks) time frame remains unresolved with a 2010 meta-analysis concluding no difference between these two groups across multiple outcomes. In an era of evidence-based medicine, surgeons are still basing their decisions on when to operate on little more than anecdotal evidence and personal preference. Clear guidance is required to determine whether the timing of surgery can optimise outcomes in this largely young and active patient cohort.

Methods

A systematic literature search was performed in January 2018 of Embase, Medline and OpenGrey in accordance with (PRISMA) guidelines. A total of 658 articles were retrieved, with 6 suitable for inclusion, covering 576 ACL reconstructions. Four meta-analyses were performed assessing subjective measures of Tegner activity scale and Lysholm score, and objective measures of arthroscopically identified meniscal and chondral injury. Additional relevant outcome measures underwent narrative review. Study bias was assessed and reported using the Downs and Black checklist.

Results

A statistically significant difference of 0.39 points was found on the Tegner activity scale in favour of early surgery within 3 weeks (RR 0.39, CI 0.10, 0.67, p = 0.008). No statistically difference was found between groups for the patient-reported Lysholm score (RR − 0.18, CI − 2.40, 2.05, p = 0.17). There was no statistically significant difference between groups for intra-operative findings of meniscal lesions (RR 0.84, CI 0.66, 1.08, p = 0.17). A trend towards significance was observed for the incidence of chondral lesions in the early surgery group (RR 0.56, CI 0.31, 1.02, p = 0.06). All the studies were rated either fair or good on the Downs and Black checklist with no study excluded due to bias.

Conclusions

Although there was a statistically significant result for the Tegner activity scale in favour of early surgery, the magnitude of the effect is unlikely to translate into any clinically meaningful difference. At present, there remains no clear evidence to determine superiority of acute/early or delayed reconstruction of a ruptured anterior cruciate ligament. Further research through methodologically robust randomised controlled trials or through the UK National Ligament Registry  may help to provide clearer guidance.

BOXIT-A Randomised Phase III Placebo-controlled Trial Evaluating the Addition of Celecoxib to Standard Treatment of Transitional Cell Carcinoma of the Bladder (CRUK/07/004)

BACKGROUND

Non-muscle-invasive bladder cancer (NMIBC) has a significant risk of recurrence despite adjuvant intravesical therapy.

OBJECTIVE

To determine whether celecoxib, a cyclo-oxygenase 2 inhibitor, reduces the risk of recurrence in NMIBC patients receiving standard treatment.

DESIGN, SETTING, AND PARTICIPANTS

BOXIT (CRUK/07/004, ISRCTN84681538) is a double-blinded, phase III, randomised controlled trial. Patients aged ≥18 yr with intermediate- or high-risk NMIBC were accrued across 51 UK centres between 1 November 2007 and 23 July 2012.

INTERVENTION

Patients were randomised (1:1) to celecoxib 200mg twice daily or placebo for 2 yr. Patients with intermediate-risk NMIBC were recommended to receive six weekly mitomycin C instillations; high-risk NMIBC cases received six weekly bacillus Calmette-Guérin and maintenance therapy.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The primary endpoint was time to disease recurrence. Analysis was by intention to treat.

RESULTS AND LIMITATIONS

A total of 472 patients were randomised (236:236). With median follow-up of 44 mo (interquartile range: 36-57), 3-yr recurrence-free rate (95% confidence interval) was as follows: celecoxib 68% (61-74%) versus placebo 64% (57-70%; hazard ratio [HR] 0.82 [0.60-1.12], p=0.2). There was no difference in high-risk (HR 0.77 [0.52-1.15], p=0.2) or intermediate-risk (HR 0.90 [0.55-1.48], p=0.7) NMIBC. Subgroup analysis suggested that time to recurrence was longer in pT1 NMIBC patients treated with celecoxib compared with those receiving placebo (HR 0.53 [0.30-0.94], interaction test p=0.04). The 3-yr progression rates in high-risk patients were low: 10% (6.5-17%) and 9.7% (6.0-15%) in celecoxib and placebo arms, respectively. Incidence of serious cardiovascular events was higher in celecoxib (5.2%) than in placebo (1.7%) group (difference +3.4% [-0.3% to 7.2%], p=0.07).

CONCLUSIONS

BOXIT did not show that celecoxib reduces the risk of recurrence in intermediate- or high-risk NMIBC, although celecoxib was associated with delayed time to recurrence in pT1 NMIBC patients. The increased risk of cardiovascular events does not support the use of celecoxib.

PATIENT SUMMARY

Celecoxib was not shown to reduce the risk of recurrence in intermediate- or high-risk non-muscle-invasive bladder cancer (NMIBC), although celecoxib was associated with delayed time to recurrence in pT1 NMIBC patients. The increased risk of cardiovascular events does not support the use of celecoxib.

The impact of hip fracture on health-related quality of life and activities of daily living: the SPARE-HIP prospective cohort study

PURPOSE

The medical morbidity and mortality associated with neck of femur fractures is well-documented, whereas there is limited data for patient-reported outcomes. The aim of this study was to characterize the impact of neck of femur fractures on activities of daily living and patient-reported health-related quality of life.

METHODS

Design and participants: Multicentric prospective cohort study. Consecutive sample patients with fragility hip fracture over 50 years old admitted in 48 hospitals in Spain.

OUTCOMES

daily living activity function (Barthel Index) and health-related quality of life (EQ-5D) pre-fracture, admission to hospital and at 1- and 4-month follow-up post-fracture.

STATISTICS

Barthel and EQ-5D over time are described as mean (SD) and median (interquartile range).

RESULTS

A total of 997 patients were recruited at baseline with 4-month outcomes available for, and 856 patients (89.5%). Barthel Index fell from 78.77 (23.75) at baseline to 43.62 (19.86) on admission to hospital with the fracture. Scores partially recovered to 54.89 (25.40) and 64.09 (21.35) at 1- and 4-month post-fracture, respectively. EQ-5D fell from a median of 0.75 (0.47-0.91) to - 0.01 (- 0.03 to 0.51) on admission. Partial recovery was observed again to (0.51 (- 0.06 to 0.67)) and (0.60 (0.10 to 0.80)) at 1- and 4-month post-fracture, respectively.

CONCLUSIONS

Hip fracture results in a large decline in the ability to perform activities of daily living and patient-reported health-related quality of life with only partial recovery amongst survivors 4-month post-fracture.

Procedural sedation of elderly patients by emergency physicians: a safety analysis of 740 patients

BACKGROUND

The elderly are perceived as a high-risk group for procedural sedation. Concern exists regarding the safety of sedation of this patient group by emergency physicians, particularly when using propofol.

METHODS

We analysed prospectively collected data on patients aged 75 yr or older undergoing sedation between October 2006 and March 2017 in the emergency department of a single centre. We used the World Society of Intravenous Anaesthesia International Sedation Task Force adverse event tool, stratifying identified adverse events according to consensus agreement.

RESULTS

Of 740 consecutive patients (median age 84 yr), 571 patients received propofol, 142 morphine and midazolam, and 27 other agents. We identified 19 sentinel events: 2 cases of hypoxia, 10 of apnoea (without hypoxaemia), 5 of hypotension, and 2 of both hypoxaemia and hypotension. We also identified 30 moderate, 41 minor, and 7 minimal risk adverse events. There were no adverse outcomes.

CONCLUSIONS

We observed safe sedation practice in this high-risk group of patients in this department. A sentinel adverse event rate of 2.6% including a hypoxaemia rate of 0.5%, with no adverse outcomes sets a benchmark for elderly sedation. We recommend quality pre-oxygenation, an initial propofol bolus of no more than 0.5 mg kg^-1, and a robust training and governance framework.

Comparative enteric viruses and coliphage removal during wastewater treatment processes in a sub-tropical environment

Microbiological safety of reclaimed water is one of the most important issues in managing potential health risks related to wastewater recycling. Presence and removal of human adenovirus (HAdV), human polyomavirus (HPyV), human torque teno virus (HTtV) and somatic coliphage family Microviridae in three wastewater treatment plants (WWTP) in sub-tropical Brisbane, Australia was investigated. All three WWTPs employ activated sludge process with added on Bardenpho process for nutrient removal. HPyV, HAdV, HTtV and Microviridae were consistently detected in the influent (10⁵ to 10⁶ Genomic copies (GC) L^-1) and secondary treated effluent (10² to 10³GCL^-1). The results of this study suggest that, under appropriate conditions, WWTPs with activated sludge process in sub-tropical climate could be an effective treatment barrier with >3 log₁₀ removal of enteric virus. The geometric mean of pooled data for each virus from all sites showed the highest removal for HPyV (3.65 log₁₀) and lowest for HAdV (2.79 log₁₀) which was statistically significant (p=0.00001). Whereas, the removal rate of HTtV and Microviridae was identical (2.81 log₁₀). A poor correlation between the presence of enteric virus in influent or effluent with routinely monitored physicochemical parameters suggests limited use of physicochemical parameters as predictors of enteric virus presence. High prevalence of HAdV in influent and effluent combined with comparatively low removal suggest that it could be used as a model microorganism for determining enteric virus removal efficacy. Additional tertiary treatment may be required prior to effluent reuse for non-potable purposes or discharge into the recreational waters to prevent exposure of people to health hazards.

Transport and potential attenuation of nitrogen in shallow groundwaters in the lower Rangitikei catchment, New Zealand

Intensive agricultural activities are generally associated with nitrogen leaching from agricultural soils, and this nitrogen has the potential to percolate and contaminate groundwater and surface waters. We assessed surface water and groundwater interactions, and nitrogen leaching and its potential attenuation in shallow groundwater in the lower Rangitikei River catchment (832km²), New Zealand. We combined regional- and local-scale field surveys and experiments, nutrient budget modelling, and hydraulic and geochemical methods, to gain an insight into leaching, transformation and transport of nitrogen via groundwaters to the river in the study area. Concurrent river flow gaugings (in January 2015) and a piezometric map, developed from measured depths to groundwater in 110 bores (in October 2014), suggest groundwater discharges to the Rangitikei River in the upper parts of the study area, while there is groundwater recharge near the coast. The groundwater redox characterisation, based on sampling and analysis of 15 mostly shallow bores (<30m below ground level (bgl)), suggests groundwater across the lower Rangitikei catchment in general is under anoxic/reduced conditions. The groundwater typically has low dissolved oxygen (DO) concentrations (<1mg/L), suggesting the subsurface environment is conducive to potential attenuation by 'denitrification' of NO₃-N in groundwater. We further measured NO₃-N attenuation in shallow groundwater piezometers (3-6mbgl) using single-well push-pull tests. We found generally low levels (<0.5mg/L) of NO₃-N in shallow groundwater piezometers (>5mbgl), despite being installed under intensive land uses, such as dairying and cropping. Our in-field push-pull tests showed NO₃-N reduction at four shallow groundwater piezometers, with the rates of reduction varying from 0.04mgNL^-1h^-1 to 1.57mgNL^-1h^-1. This highlights the importance of a sound understanding of not only the sources, but also transport and transformation, or fate, of nutrients leached from farms, to mitigate the likely impacts of land use on water quality and ecosystem health in agricultural catchments.

Diagnostic and prognostic value of delayed Gadolinium Enhanced Magnetic Resonance Imaging of Cartilage (dGEMRIC) in early osteoarthritis of the hip

BACKGROUND

Delayed Gadolinium Enhanced Magnetic Resonance Imaging of Cartilage (dGEMRIC) can detect glycosaminoglycan loss in the acetabular cartilage of asymptomatic individuals with cam morphology. The aims of this study were to explore the relationship between cam morphology and dGEMRIC values, and to explore whether baseline dGEMRIC can predict the development of radiographic hip osteoarthritis.

METHODS

Prospective cohort (SibKids) study with clinical, radiographic, and MRI assessment at baseline and five-year follow-up (n = 34). The dGEMRIC values of cartilage regions were correlated with measures of cam morphology. Receiver operating characteristic (ROC) analysis was applied to baseline variables to predict radiographic loss of joint space width.

RESULTS

Superolateral acetabular cartilage dGEMRIC values were significantly lower in participants with cam morphology (P < 0.001), defined as an alpha angle greater than 60°. There was a negative correlation between alpha angle and the dGEMRIC value of adjacent acetabular cartilage. This relationship was strongest superoanteriorly (r = -0.697 P < 0.001). There was a positive correlation between baseline dGEMRIC and the magnitude of joint space width narrowing (r = 0.398 P = 0.030). ROC analysis of combined baseline variables (positive impingement test, alpha angle, dGEMRIC ratio) gave an Area Under the Curve (AUC) of 0.75 for predicting joint space width narrowing greater than 0.5 mm within 5 years.

CONCLUSIONS

The size and position of cam morphology determines the severity and location of progressive cartilage damage, supporting the biomechanical aetiology of femoroacetabular impingement. Baseline dGEMRIC is able to predict the development of radiographic osteoarthritis. Compositional MRI offers the potential to identify patients who may benefit from early intervention to prevent the development of osteoarthritis.

What makes representation of executive women in business happen?

Purpose

The purpose of this paper is to identify the underlying organisational features, according to the gendered organisation theory, that have contributed to high levels of representation of women executives, contrary to the trend in the South African financial services industry.

Design/methodology/approach

A critical realist approach was employed, using semi-structured interviews, based on a theoretical framework of the gendered organisation. Data were aligned to the theoretical levels of critical realism.

Findings

The research found that the pool from which the successful candidates were appointed was influenced by two features. The first was the perceived attractiveness of the organisation as an employer, composed of organisational prestige, opportunity for altruism, and the sex of the CEO. The second was the role of the CEO as gatekeeper, most notably the CEO’s network and the impact of the similar-to-me paradigm during selection.

Originality/value

The utilisation of critical realism as an approach allowed for organisational features embedded in the theory of the gendered organisation to be identified and gives an indication of how the number of women at executive management level may be increased. The salient factors are the role the woman CEO played in the inclusion of more women at the executive level by virtue of her being a woman, and the attractiveness of the organisation to women employees. Organisational features identified were gendered towards the feminine.

Osseous impingement occurs early in flexion in cam-type femoroacetabular impingement

Aims

The aim of this study was to examine the real time in vivo kinematics of the hip in patients with cam-type femoroacetabular impingement (FAI).

Patients and Methods

A total of 50 patients (83 hips) underwent 4D dynamic CT scanning of the hip, producing real time osseous models of the pelvis and femur being moved through flexion, adduction, and internal rotation. The location and size of the cam deformity and its relationship to the angle of flexion of the hip and pelvic tilt, and the position of impingement were recorded.

Results

In these patients with cam-type FAI, there was significant correlation between the alpha angle and flexion to the point of impingement (mean 41.36°; 14.32° to 57.95°) (R = -0.5815 and p = < 0.001). Patients with a large cam deformity (alpha angle > 78°) had significantly less flexion to the point of impingement (mean 36.30°; 14.32° to 55.18°) than patients with a small cam deformity (alpha angle 60° to 78°) (mean 45.34°; 27.25° to 57.95°) (p = < 0.001).

Conclusion

This study has shown that cam-type impingement can occur early in flexion (40°), particularly in patients with large anterior deformities. These patients risk chondrolabral damage during routine activities such as walking, and going up stairs. These findings offer important insights into the cause of the symptoms, the mechanisms of screening and the forms of treatment available for these patients. Cite this article: Bone Joint J 2017;99-B(4 Supple B):41–8.

Public health implications of Acanthamoeba and multiple potential opportunistic pathogens in roof-harvested rainwater tanks

A study of six potential opportunistic pathogens (Acanthamoeba spp., Legionella spp., Legionella longbeachae, Pseudomonas aeruginosa, Mycobacterium avium and Mycobacterium intracellulare) and an accidental human pathogen (Legionella pneumophila) in 134 roof-harvested rainwater (RHRW) tank samples was conducted using quantitative PCR (qPCR). All five opportunistic pathogens and accidental pathogen L. pneumophila were detected in rainwater tanks except Legionella longbeachae. Concentrations ranged up to 3.1×10(6) gene copies per L rainwater for Legionella spp., 9.6×10(5) gene copies per L for P. aeruginosa, 6.8×10(5) gene copies per L for M. intracellulare, 6.6×10(5) gene copies per L for Acanthamoeba spp., 1.1×10(5) gene copies per L for M. avium, and 9.8×10(3) gene copies per L for L. pneumophila. Among the organisms tested, Legionella spp. (99% tanks) were the most prevalent followed by M. intracellulare (78%). A survey of tank-owners provided data on rainwater end-uses. Fecal indicator bacteria (FIB) Escherichia coli and Enterococcus spp. were enumerated using culture-based methods, and assessed for correlations with opportunistic pathogens and L. pneumophila tested in this study. Opportunistic pathogens did not correlate well with FIB except E. coli vs. Legionella spp. (tau=0.151, P=0.009) and E. coli vs. M. intracellulare (tau=0.14, P=0.015). However, M. avium weakly correlated with both L. pneumophila (Kendall's tau=0.017, P=0.006) and M. intracellulare (tau=0.088, P=0.027), and Legionella spp. also weakly correlated with M. intracellulare (tau=0.128, P=0.028). The presence of these potential opportunistic pathogens in tank water may present health risks from both the potable and non-potable uses documented from the current survey data.

Role of Iron in Hydrogen Sulphide Removal from Hot Gas

Yields of SO2 formed during H2S removal from N2 + H2S mixture at 800°C in the presence of Fe2O3, Mn-nodule and red mud have been determined. The largest yields were observed for Fe2O3 followed by Mn-nodule, whereas no SO2 was detected in the presence of red mud. A mechanism for H2S reaction with Fe oxides has been proposed involving the use of the component distribution in the clean gas as well as the Fe sulphides formed during adsorption. X-ray diffraction and Mossbauer spectroscopy have been used to determine the forms of Fe in the solids at the end of adsorption. FeS was the main sulphide which was always accompanied by FeS2.

Sub-Kelvin magnetic and electrical measurements in a diamond anvil cell with in situ tunability

We discuss techniques for performing continuous measurements across a wide range of pressure-field-temperature phase space, combining the milli-Kelvin temperatures of a helium dilution refrigerator with the giga-Pascal pressures of a diamond anvil cell and the Tesla magnetic fields of a superconducting magnet. With a view towards minimizing remnant magnetic fields and background magnetic susceptibility, we characterize high-strength superalloy materials for the pressure cell assembly, which allows high fidelity measurements of low-field phenomena such as superconductivity below 100 mK at pressures above 10 GPa. In situ tunability and measurement of the pressure permit experiments over a wide range of pressure, while at the same time making possible precise steps across abrupt phase transitions such as those from insulator to metal.

Multiple-aetiology enteric infections involving non-O157 Shiga toxin-producing Escherichia coli--FoodNet, 2001-2010

We describe multiple-aetiology infections involving non-O157 Shiga toxin-producing Escherichia coli (STEC) identified through laboratory-based surveillance in nine FoodNet sites from 2001 to 2010. A multiple-aetiology infection (MEI) was defined as isolation of non-O157 STEC and laboratory evidence of any of the other nine pathogens under surveillance or isolation of >1 non-O157 STEC serogroup from the same person within a 7-day period. We compared exposures of patients with MEI during 2001-2010 with those of patients with single-aetiology non-O157 STEC infections (SEI) during 2008-2009 and with those of the FoodNet population from a survey conducted during 2006-2007. In total, 1870 non-O157 STEC infections were reported; 68 (3.6%) were MEI; 60 included pathogens other than non-O157 STEC; and eight involved >1 serogroup of non-O157 STEC. Of the 68 MEI, 21 (31%) were part of six outbreaks. STEC O111 was isolated in 44% of all MEI. Of patients with MEI, 50% had contact with farm animals compared with 29% (P < 0.01) of persons with SEI; this difference was driven by infections involving STEC O111. More patients with non-outbreak-associated MEI reported drinking well water (62%) than respondents in a population survey (19%) (P < 0.01). Drinking well water and having contact with animals may be important exposures for MEI, especially those involving STEC O111.

Sewage pollution in urban stormwater runoff as evident from the widespread presence of multiple microbial and chemical source tracking markers

The concurrence of human sewage contamination in urban stormwater runoff (n=23) from six urban catchments across Australia was assessed by using both microbial source tracking (MST) and chemical source tracking (CST) markers. Out of 23 stormwater samples human adenovirus (HAv), human polyomavirus (HPv) and the sewage-associated markers; Methanobrevibacter smithii nifH and Bacteroides HF183 were detected in 91%, 56%, 43% and 96% of samples, respectively. Similarly, CST markers paracetamol (87%), salicylic acid (78%) acesulfame (96%) and caffeine (91%) were frequently detected. Twenty one samples (91%) were positive for six to eight sewage related MST and CST markers and remaining two samples were positive for five and four markers, respectively. A very good consensus (>91%) observed between the concurrence of the HF183, HAv, acesulfame and caffeine suggests good predictability of the presence of HAv in samples positive for one of the three markers. High prevalence of HAv (91%) also suggests that other enteric viruses may also be present in the stormwater samples which may pose significant health risks. This study underscores the benefits of employing a set of MST and CST markers which could include monitoring for HF183, adenovirus, caffeine and paracetamol to accurately detect human sewage contamination along with credible information on the presence of human enteric viruses, which could be used for more reliable public health risk assessments. Based on the results obtained in this study, it is recommended that some degree of treatment of captured stormwater would be required if it were to be used for non-potable purposes.

Incommensurate antiferromagnetism in a pure spin system via cooperative organization of local and itinerant moments

Materials with strong correlations are prone to spin and charge instabilities, driven by Coulomb, magnetic, and lattice interactions. In materials that have significant localized and itinerant spins, it is not obvious which will induce order. We combine electrical transport, X-ray magnetic diffraction, and photoemission studies with band structure calculations to characterize successive antiferromagnetic transitions in GdSi. GdSi has both sizable local moments and a partially nested Fermi surface, without confounding contributions from orbital effects. We identify a route to incommensurate order where neither type of moment dominates, but is rooted in cooperative feedback between them. The nested Fermi surface of the itinerant electrons induces strong interactions between local moments at the nesting vector, whereas the ordered local moments in turn provide the necessary coupling for a spin-density wave to form among the itinerant electrons. This mechanism echoes the cooperative interactions between electrons and ions in charge-density-wave materials, and should be germane across a spectrum of transition-metal and rare-earth intermetallic compounds.

A survey of the practice and management of radiotherapy linear accelerator quality control in the UK

OBJECTIVES

The objective of this study was to determine current radiotherapy linear accelerator quality control (QC) practice in the UK, as a comparative benchmark and indicator of development needs, and to raise awareness of QC as a key performance indicator.

METHODS

All UK radiotherapy centres were invited to complete an online questionnaire regarding their local QC processes, and submit their QC schedules. The range of QC tests, frequency of measurements and acceptable tolerances in use across the UK were analysed, and consensus and range statistics determined.

RESULTS

72% of the UK's 62 radiotherapy centres completed the questionnaire and 40% provided their QC schedules. 60 separate QC tests were identified from the returned schedules. There was a large variation in the total time devoted to QC between centres: interquartile range from 13 to 26 h per linear accelerator per month. There has been a move from weekly to monthly testing of output calibration in the last decade, with reliance on daily constancy testing equipment. 33% of centres thought their schedules were in need of an update and only 30% used risk-assessment approaches to determine local QC schedule content. Less than 30% of centres regularly complete all planned QC tests each month, although 96% achieve over 80% of tests.

CONCLUSIONS

A comprehensive "snapshot" of linear accelerator QC testing practice in the UK has been collated, which demonstrates reasonable agreement between centres in their stated QC test frequencies. However, intelligent design of QC schedules and management is necessary to ensure efficiency and appropriateness.

Relationship of chronic hepatitis C infection to rates of AIDS-defining illnesses in a Canadian cohort of HIV seropositive individuals receiving highly active antiretroviral therapy

BACKGROUND

The influence of chronic hepatitis C virus (HCV) infection on the risk, timing, and type of AIDS-defining illnesses (ADIs) is not well described. To this end, rates of ADIs were evaluated in a Canadian cohort of HIV seropositive individuals receiving highly active antiretroviral therapy (HAART).

METHODS

ADIs were classified into 6 Centers for Disease Control and Prevention (CDC)-defined etiological subgroups: non-Hodgkin lymphoma, viral infection, bacterial infection, HIV-related disease, protozoal infection, and mycotic infection. Generalized estimating equation (GEE) Poisson regression models were used to estimate the effect of HCV on rates of ADIs after adjusting for covariates.

RESULTS

Among 2,706 HAART recipients, 768 (28%) were HCV coinfected. Rates of all ADIs combined and of bacterial infection, HIV-related disease, and mycotic infection were increased in HCV-coinfected persons and among those with CD4 counts <200 cells/mm3 HCV was associated with an increased risk of ADIs (rate ratio [RR], 1.38; 95% CI, 1.01-1.88) and a 2-fold increased risk of mycotic infections (RR, 2.21; 95% CI, 1.35-3.62) in univariate analyses and after adjusting for age, baseline viral load, baseline CD4 count, and region of Canada. However, after further adjustment for HAART interruptions, HCV was no longer associated with an increased rate of ADIs overall (RR, 1.13; 95% CI, 0.80-1.59), but remained associated with an increased rate of mycotic infections (RR, 1.97, 95% CI, 1.08-3.61).

CONCLUSION

Although HCV coin-fected individuals are at increased risk of developing ADIs overall, our analysis suggests that behavioral variables associated with HCV (including rates of retention on HAART), and not biological interactions with HCV itself, are primarily responsible.

Measurement of the neutron radius of 208Pb through parity violation in electron scattering

We report the first measurement of the parity-violating asymmetry A(PV) in the elastic scattering of polarized electrons from 208Pb. A(PV) is sensitive to the radius of the neutron distribution (R(n)). The result A(PV)=0.656±0.060(stat)±0.014(syst) ppm corresponds to a difference between the radii of the neutron and proton distributions R(n)-R(p)=0.33(-0.18)(+0.16) fm and provides the first electroweak observation of the neutron skin which is expected in a heavy, neutron-rich nucleus.

Analysis of regional radiotherapy dosimetry audit data and recommendations for future audits

OBJECTIVES

Regional interdepartmental dosimetry audits within the UK provide basic assurances of the dosimetric accuracy of radiotherapy treatments.

METHODS

This work reviews several years of audit results from the South East Central audit group including megavoltage (MV) and kilovoltage (kV) photons, electrons and iodine-125 seeds.

RESULTS

Apart from some minor systematic errors that were resolved, the results of all audits have been within protocol tolerances, confirming the long-term stability and agreement of basic radiation dosimetric parameters between centres in the audit region. There is some evidence of improvement in radiation dosimetry with the adoption of newer codes of practice.

CONCLUSION

The value of current audit methods and the limitations of peer-to-peer auditing is discussed, particularly the influence of the audit schedule on the results obtained, where no "gold standard" exists. Recommendations are made for future audits, including an essential requirement to maintain the monitoring of basic fundamental dosimetry, such as MV photon and electron output, but audits must also be developed to include new treatment technologies such as image-guided radiotherapy and address the most common sources of error in radiotherapy.

High prevalence of food insecurity among HIV-infected individuals receiving HAART in a resource-rich setting

This study aimed to assess the prevalence and correlates of food insecurity in a cohort of HIV-infected individuals on highly active antiretroviral therapy (HAART) in British Columbia (BC), Canada. Adults receiving HAART voluntarily enrolled into the Longitudinal Investigations into Supportive and Ancillary Health Services (LISA) cohort. Individual food insecurity was measured using a modified version of the Radimer/Cornell Questionnaire. We performed bivariate analyses to determine differences between explanatory variables for individuals who were food secure and food insecure. We performed logistic regression to determine independent predictors of food insecurity. Of the 457 individuals enrolled in the LISA cohort, 324 (71.0%) were found to be food insecure. Multivariate analysis indicated that individuals who had an annual incomes less than $15,000 (odds ratio [OR] 3.15, 95% confidence interval [CI] 1.83, 5.44), used illicit drugs (OR 1.85, 95% CI 1.03, 3.33), smoked tobacco (OR 2.30, 95% CI 1.30, 4.07), had depressive symptoms (OR 2.34, 95% CI 1.38, 3.96), and were younger (OR 0.95, 95% CI, 0.92, 0.98) were more likely to be food insecure. Our results demonstrated a high (71%) prevalence of food insecurity among HIV-infected individuals receiving HAART in this resource-rich setting, and that food insecurity is associated with a compendium of environmental and behavioral factors. More research is needed to understand the biological and social pathways linking food insecurity to these variables in order to identify program strategies that can effectively improve food security among HIV-infected populations.