Survival of Substructure within Dark Matter Haloes

Using high resolution cosmological N-body simulations, we investigate the survival of dark matter satellites falling into larger haloes. Satellites preserve their identity for some time after merging. We compute their loss of mass, energy and angular momentum as dynamical friction, tidal forces and collisions with other satellites dissolve them. We also analyse the evolution of their internal structure. Satellites with less than a few per cent the mass of the main halo may survive for several billion years, whereas larger satellites rapidly sink into the center of the main halo potential well and lose their identity. Penetrating encounters between satellites are frequent and may lead to significant mass loss and disruption. Only a minor fraction of cluster mass (10 per cent on average) is bound to substructure at most redshifts of interest. We discuss the application of these results to the survival and extent of dark matter haloes associated with cluster galaxies, and to interactions between galaxies in clusters. We find that 35-40 per cent of galaxy dark matter haloes are disrupted by the present time. The fraction of satellites undergoing close encounters is similar to the fraction of interacting or merging galaxies in clusters at moderate redshift.Comment: 16 pages, Latex, 14 Postscript figures. Submitted to MNRAS. Postscript version also available at http://www.mpa-garching.mpg.de/~bep

Hormone replacement therapy and prevention of vertebral fractures: a meta-analysis of randomised trials

BACKGROUND: Hormone replacement therapy (HRT) is often seen as the treatment of choice for preventing fractures in women. We undertook a recent meta-analysis of randomised trials which suggested that HRT reduced non-vertebral fractures by 30%. In this analysis we extend that analysis to vertebral fractures. METHODS: We searched the main electronic databases until the end of August 2001. We sought all randomised controlled trials (RCTs) of HRT where women had been randomised to at least 12 months of HRT or to no HRT. RESULTS: We found 13 RCTs. Overall there was a 33% reduction in vertebral factures (95% confidence interval (CI) 45% to 98%). CONCLUSIONS: This review and meta-analysis showed a significant reduction in vertebral fractures associated with HRT use

Randomised controlled trial of exercise for low back pain : clinical outcomes, costs and preferences

Objective: To evaluate effectiveness of an exercise programme in a community setting for patients with low back pain to encourage a return to normal activities. Design: Randomised controlled trial of progressive exercise programme compared with usual primary care management. Patients' preferences for type of management were elicited independently of randomisation. Participants: 187 patients aged 18-60 years with mechanical low back pain of 4 weeks to 6 months' duration. Interventions: Exercise classes led by a physiotherapist that included strengthening exercises for all main muscle groups, stretching exercises, relaxation session, and brief education on back care. A cognitive-behavioural approach was used. Main outcome measures: Assessments of debilitating effects of back pain before and after intervention and at 6 months and 1 year later. Measures included Roland disability questionnaire, Aberdeen back pain scale, pain diaries, and use of healthcare services. Results: At 6 weeks after randomisation, the intervention group improved marginally more than the control group on the disability questionnaire and reported less distressing pain. At 6 months and 1 year, the intervention group showed significantly greater improvement in the disability questionnaire score (mean difference in changes 1.35, 95% confidence interval 0.13 to 2.57). At 1 year, the intervention group also showed significantly greater improvement in the Aberdeen back pain scale (4.44, 1.01 to 7.87) and reported only 378 days off work compared with 607 in the control group. The intervention group used fewer healthcare resources. Outcome was not influenced by patients' preferences. Conclusions: The exercise class was more clinically effective than traditional general practitioner management, regardless of patient preference, and was cost effective

Systematic review of topical treatments for fungal infections of the skin and nails of the feet

OBJECTIVE: To identify and synthesise the evidence for efficacy and cost effectiveness of topical treatments for superficial fungal infections of the skin and nails of the feet. DESIGN: Systematic review. INTERVENTIONS: Topical treatments for superficial fungal infections. MAIN OUTCOME MEASURES: Cure confirmed by culture and microscopy for skin and by culture for nails in patients with clinically diagnosed fungal infections. RESULTS: Of 126 trials identified in 121 papers, 72 (57.1%) met the inclusion criteria. Placebo controlled trials yielded pooled relative risks of failure to cure skin infections: allylamines (0.30, 95% confidence interval 0.24 to 0.38); azoles (0.54, 0.42 to 0.68); undecenoic acid (0.28, 0.11 to 0.74); and tolnaftate (0.46, 0.17 to 1.22). Although meta-analysis of 11 trials comparing allylamines and azoles showed a relative risk of failure to cure of 0.88 (0.78 to 0.99) in favour of allylamines, there was evidence of language bias. Seven reports in English favoured allylamines (0.79, 0.69 to 0.91), but four reports in foreign languages showed no difference between the two drugs (1.01, 0.90 to 1.13). Neither trial of nail infections showed significant differences between alternative topical treatments. CONCLUSIONS: Allylamines, azoles, and undecenoic acid were efficacious in placebo controlled trials. There are sufficient comparative trials to judge relative efficacy only between allylamines and azoles. Allylamines cure slightly more infections than azoles but are much more expensive than azoles. The most cost effective strategy is first to treat with azoles or undecenoic acid and to use allylamines only if that fails

Cross-Modality Image Registration using a Training-Time Privileged Third Modality

— In this work, we consider the task of pairwise cross-modality image registration, which may benefit from exploiting additional images available only at training time from an additional modality that is different to those being registered. As an example, we focus on aligning intra-subject multiparametric Magnetic Resonance (mpMR) images, between T2-weighted (T2w) scans and diffusionweighted scans with high b-value (DWI_{high−b}). For the application of localising tumours in mpMR images, diffusion scans with zero b-value (DWI_{b=0}) are considered easier to register to T2w due to the availability of corresponding features. We propose a learning from privileged modality algorithm, using a training-only imaging modality DWIb=0, to support the challenging multi-modality registration problems. We present experimental results based on 369 sets of 3D multiparametric MRI images from 356 prostate cancer patients and report, with statistical significance, a lowered median target registration error of 4.34 mm, when registering the holdout DWI_{high−b} and T2w image pairs, compared with that of 7.96 mm before registration. Results also show that the proposed learning-based registration networks enabled efficient registration with comparable or better accuracy, compared with a classical iterative algorithm and other tested learning-based methods with/without the additional modality. These compared algorithms also failed to produce any significantly improved alignment between DWI_{high−b} and T2w in this challenging application

A Photometric Method for Quantifying Asymmetries in Disk Galaxies

A photometric method for quantifying deviations from axisymmetry in optical images of disk galaxies is applied to a sample of 32 face-on and nearly face-on spirals. The method involves comparing the relative fluxes contained within trapezoidal sectors arranged symmetrically about the galaxy center of light, excluding the bulge and/or barred regions. Such a method has several advantages over others, especially when quantifying asymmetry in flocculent galaxies. Specifically, the averaging of large regions improves the signal-to-noise in the measurements; the method is not strongly affected by the presence of spiral arms; and it identifies the kinds of asymmetry that are likely to be dynamically important. Application of this "method of sectors" to R-band images of 32 disk galaxies indicates that about 30% of spirals show deviations from axisymmetry at the 5-sigma level.Comment: 17 pages, 2 tables and 6 figures, uses psfig and AAS LaTex; to appear in A

The Importance Of Multi-Reader Assessment For External Validation Of Prostate Lesion Classification Models Using Quantitative MpMRI

Machine learning for classifying prostate mpMRI lesions may help reduce unnecessary biopsies. However, external validation with multiple scanners and readers is required before the clinical adoption of such models can be considered. Two readers validated a previously published and well-performing logistic regression model on an external cohort. The model performance was not generalisable and offered no advantage to using PSAd cut-offs, and there was marked variation in model score related to contour differences from different readers. This potential variability should be investigated in future models which use quantitative MRI

An international survey and modified Delphi process revealed editors' perceptions, training needs, and ratings of competency-related statements for the development of core competencies for scientific editors of biomedical journals

Background: Scientific editors (i.e., those who make decisions on the content and policies of a journal) have a central role in the editorial process at biomedical journals. However, very little is known about the training needs of these editors or what competencies are required to perform effectively in this role. Methods: We conducted a survey of perceptions and training needs among scientific editors from major editorial organizations around the world, followed by a modified Delphi process in which we invited the same scientific editors to rate the importance of competency-related statements obtained from a previous scoping review. Results: A total of 148 participants completed the survey of perceptions and training needs. At least 80% of participants agreed on six of the 38 skill and expertise-related statements presented to them as being important or very important to their role as scientific editors. At least 80% agreed on three of the 38 statements as necessary skills they perceived themselves as possessing (well or very well). The top five items on participants’ list of top training needs were training in statistics, research methods, publication ethics, recruiting and dealing with peer reviewers, and indexing of journals. The three rounds of the Delphi were completed by 83, 83, and 73 participants, respectively, which ultimately produced a list of 23 “highly rated” competency-related statements and another 86 “included” items. Conclusion: Both the survey and the modified Delphi process will be critical for understanding knowledge and training gaps among scientific editors when designing curriculum around core competencies in the future

Improving response rates using a monetary incentive for patient completion of questionnaires: an observational study

Background: Poor response rates to postal questionnaires can introduce bias and reduce the statistical power of a study. To improve response rates in our trial in primary care we tested the effect of introducing an unconditional direct payment of 5 pound for the completion of postal questionnaires. Methods: We recruited patients in general practice with knee problems from sites across the United Kingdom. An evidence-based strategy was used to follow-up patients at twelve months with postal questionnaires. This included an unconditional direct payment of 5 pound to patients for the completion and return of questionnaires. The first 105 patients did not receive the 5 pound incentive, but the subsequent 442 patients did. We used logistic regression to analyse the effect of introducing a monetary incentive to increase the response to postal questionnaires. Results: The response rate following reminders for the historical controls was 78.1% ( 82 of 105) compared with 88.0% ( 389 of 442) for those patients who received the 5 pound payment (diff = 9.9%, 95% CI 2.3% to 19.1%). Direct payments significantly increased the odds of response ( adjusted odds ratio = 2.2, 95% CI 1.2 to 4.0, P = 0.009) with only 12 of 442 patients declining the payment. The incentive did not save costs to the trial - the extra cost per additional respondent was almost 50 pound. Conclusion: The direct payment of 5 pound significantly increased the completion of postal questionnaires at negligible increase in cost for an adequately powered study

A scoping review of competencies for scientific editors of biomedical journals

Background Biomedical journals are the main route for disseminating the results of health-related research. Despite this, their editors operate largely without formal training or certification. To our knowledge, no body of literature systematically identifying core competencies for scientific editors of biomedical journals exists. Therefore, we aimed to conduct a scoping review to determine what is known on the competency requirements for scientific editors of biomedical journals. Methods We searched the MEDLINE®, Cochrane Library, Embase®, CINAHL, PsycINFO, and ERIC databases (from inception to November 2014) and conducted a grey literature search for research and non-research articles with competency-related statements (i.e. competencies, knowledge, skills, behaviors, and tasks) pertaining to the role of scientific editors of peer-reviewed health-related journals. We also conducted an environmental scan, searched the results of a previous environmental scan, and searched the websites of existing networks, major biomedical journal publishers, and organizations that offer resources for editors. Results A total of 225 full-text publications were included, 25 of which were research articles. We extracted a total of 1,566 statements possibly related to core competencies for scientific editors of biomedical journals from these publications. We then collated overlapping or duplicate statements which produced a list of 203 unique statements. Finally, we grouped these statements into seven emergent themes: (1) dealing with authors, (2) dealing with peer reviewers, (3) journal publishing, (4) journal promotion, (5) editing, (6) ethics and integrity, and (7) qualities and characteristics of editors. Discussion To our knowledge, this scoping review is the first attempt to systematically identify possible competencies of editors. Limitations are that (1) we may not have captured all aspects of a biomedical editor’s work in our searches, (2) removing redundant and overlapping items may have led to the elimination of some nuances between items, (3) restricting to certain databases, and only French and English publications, may have excluded relevant publications, and (4) some statements may not necessarily be competencies. Conclusion This scoping review is the first step of a program to develop a minimum set of core competencies for scientific editors of biomedical journals which will be followed by a training needs assessment, a Delphi exercise, and a consensus meeting