University of Leeds

About: University of Leeds is a education organization based out in Leeds, United Kingdom. It is known for research contribution in the topics: Population & Context (language use). The organization has 43481 authors who have published 101856 publications receiving 3672065 citations. The organization is also known as: Leeds University.

Aerosol mass spectrometer constraint on the global secondary organic aerosol budget

Abstract: . The budget of atmospheric secondary organic aerosol (SOA) is very uncertain, with recent estimates suggesting a global source of between 12 and 1820 Tg (SOA) a−1. We used a dataset of aerosol mass spectrometer (AMS) observations from 34 different surface locations to evaluate the GLOMAP global chemical transport model. The standard model simulation (which included SOA from monoterpenes only) underpredicted organic aerosol (OA) observed by the AMS and had little skill reproducing the variability in the dataset. We simulated SOA formation from biogenic (monoterpenes and isoprene), lumped anthropogenic and lumped biomass burning volatile organic compounds (VOCs) and varied the SOA yield from each precursor source to produce the best overall match between model and observations. We assumed that SOA is essentially non-volatile and condenses irreversibly onto existing aerosol. Our best estimate of the SOA source is 140 Tg (SOA) a−1 but with a large uncertainty range which we estimate to be 50–380 Tg (SOA) a−1. We found the minimum in normalised mean error (NME) between model and the AMS dataset when we assumed a large SOA source (100 Tg (SOA) a−1) from sources that spatially matched anthropogenic pollution (which we term antropogenically controlled SOA). We used organic carbon observations compiled by Bahadur et al. (2009) to evaluate our estimated SOA sources. We found that the model with a large anthropogenic SOA source was the most consistent with these observations, however improvement over the model with a large biogenic SOA source (250 Tg (SOA) a−1) was small. We used a dataset of 14C observations from rural locations to evaluate our estimated SOA sources. We estimated a maximum of 10 Tg (SOA) a−1 (10 %) of the anthropogenically controlled SOA source could be from fossil (urban/industrial) sources. We suggest that an additional anthropogenic source is most likely due to an anthropogenic pollution enhancement of SOA formation from biogenic VOCs. Such an anthropogenically controlled SOA source would result in substantial climate forcing. We estimated a global mean aerosol direct effect of −0.26 ± 0.15 Wm−2 and indirect (cloud albedo) effect of −0.6+0.24−0.14 Wm−2 from anthropogenically controlled SOA. The biogenic and biomass SOA sources are not well constrained with this analysis due to the limited number of OA observations in regions and periods strongly impacted by these sources. To further improve the constraints by this method, additional OA observations are needed in the tropics and the Southern Hemisphere.

Predictors of joint damage in patients with early rheumatoid arthritis treated with high‐dose methotrexate with or without concomitant infliximab: Results from the ASPIRE trial

Abstract: Objective To identify disease characteristics leading to progression of joint damage in patients with early rheumatoid arthritis (RA) treated with methotrexate (MTX) versus those treated with infliximab plus MTX. Methods Patients who had not previously been treated with MTX with active RA were randomly assigned to receive escalating doses of MTX up to 20 mg/week plus placebo or infliximab at weeks 0, 2, and 6, and every 8 weeks thereafter through week 46. Radiographic joint damage was assessed using the modified Sharp/van der Heijde score (SHS). The relationship between disease activity measures at baseline and week 14, as well as those averaged over time, were examined in relation to the change in SHS from baseline through week 54. Results C-reactive protein (CRP) levels, erythrocyte sedimentation rate (ESR), and swollen joint count were associated with greater joint damage progression in the MTX-only group, while none of these parameters was associated with progression in the infliximab plus MTX group. Mean changes in SHS among patients in the highest CRP (≥3 mg/dl) and ESR (≥52 mm/hour) tertiles in the MTX-only group were 5.62 and 5.89, respectively, compared with 0.73 and 1.12 in the infliximab plus MTX group (P < 0.001). Patients with greater joint damage at baseline (SHS ≥10.5) showed less progression with infliximab plus MTX compared with MTX alone (−0.39 versus 4.11; P < 0.001). Patients receiving MTX alone who had persistently active disease at week 14 showed greater radiographic progression of joint damage than those taking MTX plus infliximab. Conclusion High CRP level, high ESR, or persistent disease activity was associated with greater radiographic progression in the group taking MTX alone, while little radiographic progression was seen in patients receiving both MTX and infliximab, regardless of the abnormal levels of these traditional predictors.

Normative values for the Foot Posture Index.

Abstract: The Foot Posture Index (FPI) is a validated method for quantifying standing foot posture, and is being used in a variety of clinical settings. There have however, been no normative data available to date for comparison and reference. This study aimed to establish normative FPI reference values. Studies reporting FPI data were identified by searching online databases. Nine authors contributed anonymised versions of their original datasets comprising 1648 individual observations. The datasets included information relating to centre, age, gender, pathology (if relevant), FPI scores and body mass index (BMI) where available. FPI total scores were transformed to interval logit scores as per the Rasch model and normal ranges were defined. Comparisons between groups employed t-tests or ANOVA models as appropriate and data were explored descriptively and graphically. The main analysis based on a normal healthy population (n = 619) confirmed that a slightly pronated foot posture is the normal position at rest (mean back transformed FPI raw score = +4). A 'U' shaped relationship existed for age, with minors and older adults exhibiting significantly higher FPI scores than the general adult population (F = 51.07, p < 0.001). There was no difference between the FPI scores of males and females (2.3 versus 2.5; t = -1.44, p = 0.149). No relationship was found between the FPI and BMI. Systematic differences from the adult normals were confirmed in patients with neurogenic and idiopathic cavus (F = 216.981, p < 0.001), indicating some sensitivity of the instrument to detect a posturally pathological population. A set of population norms for children, adults and older people have been derived from a large sample. Foot posture is related to age and the presence of pathology, but not influenced by gender or BMI. The normative values identified may assist in classifying foot type for the purpose of research and clinical decision making.

Social prescribing: less rhetoric and more reality. A systematic review of the evidence

Abstract: Objectives Social prescribing is a way of linking patients in primary care with sources of support within the community to help improve their health and well-being. Social prescribing programmes are being widely promoted and adopted in the UK National Health Service and so we conducted a systematic review to assess the evidence for their effectiveness. Setting/data sources Nine databases were searched from 2000 to January 2016 for studies conducted in the UK. Relevant reports and guidelines, websites and reference lists of retrieved articles were scanned to identify additional studies. All the searches were restricted to English language only. Participants Systematic reviews and any published evaluation of programmes where patient referral was made from a primary care setting to a link worker or facilitator of social prescribing were eligible for inclusion. Risk of bias for included studies was undertaken independently by two reviewers and a narrative synthesis was performed. Primary and secondary outcome measures Primary outcomes of interest were any measures of health and well-being and/or usage of health services. Results We included a total of 15 evaluations of social prescribing programmes. Most were small scale and limited by poor design and reporting. All were rated as a having a high risk of bias. Common design issues included a lack of comparative controls, short follow-up durations, a lack of standardised and validated measuring tools, missing data and a failure to consider potential confounding factors. Despite clear methodological shortcomings, most evaluations presented positive conclusions. Conclusions Social prescribing is being widely advocated and implemented but current evidence fails to provide sufficient detail to judge either success or value for money. If social prescribing is to realise its potential, future evaluations must be comparative by design and consider when, by whom, for whom, how well and at what cost. Trial registration number PROSPERO Registration: CRD42015023501.