Statistical Mechanics of Learning: A Variational Approach for Real Data

Using a variational technique, we generalize the statistical physics approach of learning from random examples to make it applicable to real data. We demonstrate the validity and relevance of our method by computing approximate estimators for generalization errors that are based on training data alone.Comment: 4 pages, 2 figure

Frequency format diagram and probability chart for breast cancer risk communication: a prospective, randomized trial

<p>Abstract</p> <p>Background</p> <p>Breast cancer risk education enables women make informed decisions regarding their options for screening and risk reduction. We aimed to determine whether patient education regarding breast cancer risk using a bar graph, with or without a frequency format diagram, improved the accuracy of risk perception.</p> <p>Methods</p> <p>We conducted a prospective, randomized trial among women at increased risk for breast cancer. The main outcome measurement was patients' estimation of their breast cancer risk before and after education with a bar graph (BG group) or bar graph plus a frequency format diagram (BG+FF group), which was assessed by previsit and postvisit questionnaires.</p> <p>Results</p> <p>Of 150 women in the study, 74 were assigned to the BG group and 76 to the BG+FF group. Overall, 72% of women overestimated their risk of breast cancer. The improvement in accuracy of risk perception from the previsit to the postvisit questionnaire (BG group, 19% to 61%; BG+FF group, 13% to 67%) was not significantly different between the 2 groups (<it>P </it>= .10). Among women who inaccurately perceived very high risk (≥ 50% risk), inaccurate risk perception decreased significantly in the BG+FF group (22% to 3%) compared with the BG group (28% to 19%) (<it>P </it>= .004).</p> <p>Conclusion</p> <p>Breast cancer risk communication using a bar graph plus a frequency format diagram can improve the short-term accuracy of risk perception among women perceiving inaccurately high risk.</p

Patient-reported measurement of time to diagnosis in cancer: development of the Cancer Symptom Interval Measure (C-SIM) and randomised controlled trial of method of delivery

Background: The duration between first symptom and a cancer diagnosis is important because, if shortened, may lead to earlier stage diagnosis and improved cancer outcomes. We have previously developed a tool to measure this duration in newly-diagnosed patients. In this two-phase study, we aimed further improve our tool and to conduct a trial comparing levels of anxiety between two modes of delivery: self-completed versus researcher-administered. Methods: In phase 1, ten patients completed the modified tool and participated in cognitive debrief interviews. In phase 2, we undertook a Randomised Controlled Trial (RCT) of the revised tool (Cancer Symptom Interval Measure (C-SIM)) in three hospitals for 11 different cancers. Respondents were invited to provide either exact or estimated dates of first noticing symptoms and presenting them to primary care. The primary outcome was anxiety related to delivery mode, with completeness of recording as a secondary outcome. Dates from a subset of patients were compared with GP records. Results: After analysis of phase 1 interviews, the wording and format were improved. In phase 2, 201 patients were randomised (93 self-complete and 108 researcher-complete). Anxiety scores were significantly lower in the researcher-completed group, with a mean rank of 83.5; compared with the self-completed group, with a mean rank of 104.0 (Mann-Whitney U = 3152, p = 0.007). Completeness of data was significantly better in the researcher-completed group, with no statistically significant difference in time taken to complete the tool between the two groups. When comparing the dates in the patient questionnaires with those in the GP records, there was evidence in the records of a consultation on the same date or within a proscribed time window for 32/37 (86%) consultations; for estimated dates there was evidence for 23/37 consultations (62%). Conclusions: We have developed and tested a tool for collecting patient-reported data relating to appraisal intervals, help-seeking intervals, and diagnostic intervals in the cancer diagnostic pathway for 11 separate cancers, and provided evidence of its acceptability, feasibility and validity. This is a useful tool to use in descriptive and epidemiological studies of cancer diagnostic journeys, and causes less anxiety if administered by a researcher

Injuries in youth football and the relationship to player maturation: an analysis of time-loss injuries during four seasons in an English elite male football academy

A better insight into injuries in elite youth football may inform prevention strategies. The purpose of this prospective cohort study was to investigate the frequency, incidence and pattern of time-loss injuries in an elite male football academy, exploring injuries in relation to age and maturation status. Across four consecutive playing seasons, playing exposure and injuries to all academy players (U’9 to U’21) were recorded by club medical staff. Maturation status at the time of injury was also calculated for players competing in U’13 to U’16 aged squads. Time-loss injury occurrence and maturation status at time of injury were the main outcome measures. A total of 603 time-loss injuries were recorded, from 190 different players. Playing exposure was 229,317 hours resulting in an overall injury rate of 2.4 p/1000h, ranging from 0.7 p/1000h (U’11) to 4.8 p/1000h (u’21). Most injuries were traumatic in mechanism (73%). The most common injury location was the thigh (23%) and the most common injury type was muscle injury (29%) combining to provide the most common injury diagnosis; thigh muscle injury (17%). In U’13-U’16 players, a higher number of injuries to early-maturing players were observed in U’13-U’14 players, whilst more injuries to U’15-U’16 players occurred when classed as ‘on-time’ in maturity status. Maturation status did not statistically relate to injury pattern, however knee bone (not-fracture) injuries peaked in U’13 players whilst hip/groin muscle injuries peaked in U’15 players

Uncertainty quantification in graph-based classification of high dimensional data

Classification of high dimensional data finds wide-ranging applications. In many of these applications equipping the resulting classification with a measure of uncertainty may be as important as the classification itself. In this paper we introduce, develop algorithms for, and investigate the properties of, a variety of Bayesian models for the task of binary classification; via the posterior distribution on the classification labels, these methods automatically give measures of uncertainty. The methods are all based around the graph formulation of semi-supervised learning. We provide a unified framework which brings together a variety of methods which have been introduced in different communities within the mathematical sciences. We study probit classification in the graph-based setting, generalize the level-set method for Bayesian inverse problems to the classification setting, and generalize the Ginzburg-Landau optimization-based classifier to a Bayesian setting; we also show that the probit and level set approaches are natural relaxations of the harmonic function approach introduced in [Zhu et al 2003]. We introduce efficient numerical methods, suited to large data-sets, for both MCMC-based sampling as well as gradient-based MAP estimation. Through numerical experiments we study classification accuracy and uncertainty quantification for our models; these experiments showcase a suite of datasets commonly used to evaluate graph-based semi-supervised learning algorithms.Comment: 33 pages, 14 figure

The Bolocam Galactic Plane Survey: Survey Description and Data Reduction

We present the Bolocam Galactic Plane Survey (BGPS), a 1.1 mm continuum survey at 33" effective resolution of 170 square degrees of the Galactic Plane visible from the northern hemisphere. The survey is contiguous over the range -10.5 < l < 90.5, |b| < 0.5 and encompasses 133 square degrees, including some extended regions |b| < 1.5. In addition to the contiguous region, four targeted regions in the outer Galaxy were observed: IC1396, a region towards the Perseus Arm, W3/4/5, and Gem OB1. The BGPS has detected approximately 8400 clumps over the entire area to a limiting non-uniform 1-sigma noise level in the range 11 to 53 mJy/beam in the inner Galaxy. The BGPS source catalog is presented in a companion paper (Rosolowsky et al. 2010). This paper details the survey observations and data reduction methods for the images. We discuss in detail the determination of astrometric and flux density calibration uncertainties and compare our results to the literature. Data processing algorithms that separate astronomical signals from time-variable atmospheric fluctuations in the data time-stream are presented. These algorithms reproduce the structure of the astronomical sky over a limited range of angular scales and produce artifacts in the vicinity of bright sources. Based on simulations, we find that extended emission on scales larger than about 5.9' is nearly completely attenuated (> 90%) and the linear scale at which the attenuation reaches 50% is 3.8'. Comparison with other millimeter-wave data sets implies a possible systematic offset in flux calibration, for which no cause has been discovered. This presentation serves as a companion and guide to the public data release through NASA's Infrared Processing and Analysis Center (IPAC) Infrared Science Archive (IRSA). New data releases will be provided through IPAC IRSA with any future improvements in the reduction.Comment: Accepted for publication in Astrophysical Journal Supplemen

the relationship between alcohol consumption and vascular complications and mortality in individuals with type 2 diabetes

OBJECTIVE Moderate alcohol consumption has been associated with a reduced risk of mortality and coronary artery disease. The relationship between cardiovascular health and alcohol use in type 2 diabetes is less clear. The current study assesses the effects of alcohol use among participants in the Action in Diabetes and Vascular Disease: Preterax and Diamicron Modified-Release Controlled Evaluation (ADVANCE) trial. RESEARCH DESIGN AND METHODS The effects of alcohol use were explored using Cox regression models, adjusted for potential confounders. The study end points were cardiovascular events (cardiovascular death, myocardial infarction, and stroke), microvascular complications (new or worsening nephropathy or retinopathy), and all-cause mortality. RESULTS During a median of 5 years of follow-up, 1,031 (9%) patients died, 1,147 (10%) experienced a cardiovascular event, and 1,136 (10%) experienced a microvascular complication. Compared with patients who reported no alcohol consumption, those who reported moderate consumption had fewer cardiovascular events (adjusted hazard ratio [aHR] 0.83; 95% CI 0.72–0.95; P = 0.008), less microvascular complications (aHR 0.85; 95% CI 0.73–0.99; P = 0.03), and lower all-cause mortality (aHR 0.87; 96% CI 0.75–1.00; P = 0.05). The benefits were particularly evident in participants who drank predominantly wine (cardiovascular events aHR 0.78, 95% CI 0.63–0.95, P = 0.01; all-cause mortality aHR 0.77, 95% CI 0.62–0.95, P = 0.02). Compared with patients who reported no alcohol consumption, those who reported heavy consumption had dose-dependent higher risks of cardiovascular events and all-cause mortality. CONCLUSION In patients with type 2 diabetes, moderate alcohol use, particularly wine consumption, is associated with reduced risks of cardiovascular events and all-cause mortality

Physical characteristics of localized surface plasmons resulting from nano-scale structured multi-layer thin films deposited on D-shaped optical fiber

Novel surface plasmonic optical fiber sensors have been fabricated using multiple coatings deposited on a lapped section of a single mode fiber. UV laser irradiation processing with a phase mask produces a nano-scaled surface relief grating structure resembling nano-wires. The resulting individual corrugations produced by material compaction are approximately 20 μm long with an average width at half maximum of 100 nm and generate localized surface plasmons. Experimental data are presented that show changes in the spectral characteristics after UV processing, coupled with an overall increase in the sensitivity of the devices to surrounding refractive index. Evidence is presented that there is an optimum UV dosage (48 joules) over which no significant additional optical change is observed. The devices are characterized with regards to change in refractive index, where significantly high spectral sensitivities in the aqueous index regime are found, ranging up to 4000 nm/RIU for wavelength and 800 dB/RIU for intensity

The Bolocam Galactic Plane Survey: II. Catalog of The Image Data

We present a catalog of 8358 sources extracted from images produced by the Bolocam Galactic Plane Survey (BGPS). The BGPS is a survey of the millimeter dust continuum emission from the northern Galactic plane. The catalog sources are extracted using a custom algorithm, Bolocat, which was designed specifically to identify and characterize objects in the large-area maps generated from the Bolocam instrument. The catalog products are designed to facilitate follow-up observations of these relatively unstudied objects. The catalog is 98% complete from 0.4 Jy to 60 Jy over all object sizes for which the survey is sensitive ( \u3c 3\u27.5). We find that the sources extracted can best be described as molecular clumps-large dense regions in molecular clouds linked to cluster formation. We find that the flux density distribution of sources follows a power law with dN/dS alpha S(-2.4+/-0.1) and that the mean Galactic latitude for sources is significantly below the midplane: \u3c b \u3e = (-0 degrees.095 +/- 0 degrees.001)