Suppose x is an unknown vector in Ropfm (a digital image or signal); we plan to measure n general linear functionals of x and then reconstruct. If x is known to be compressible by transform coding with a known transform, and we reconstruct via the nonlinear procedure defined here, the number of measurements n can be dramatically smaller than the size m. Thus, certain natural classes of images with m pixels need only n=O(m1/4log5/2(m)) nonadaptive nonpixel samples for faithful recovery, as opposed to the usual m pixel samples. More specifically, suppose x has a sparse representation in some orthonormal basis (e.g., wavelet, Fourier) or tight frame (e.g., curvelet, Gabor)-so the coefficients belong to an lscrp ball for 0<ples1. The N most important coefficients in that expansion allow reconstruction with lscr2 error O(N1/2-1p/). It is possible to design n=O(Nlog(m)) nonadaptive measurements allowing reconstruction with accuracy comparable to that attainable with direct knowledge of the N most important coefficients. Moreover, a good approximation to those N important coefficients is extracted from the n measurements by solving a linear program-Basis Pursuit in signal processing. The nonadaptive measurements have the character of "random" linear combinations of basis/frame elements. Our results use the notions of optimal recovery, of n-widths, and information-based complexity. We estimate the Gel'fand n-widths of lscrp balls in high-dimensional Euclidean space in the case 0<ples1, and give a criterion identifying near- optimal subspaces for Gel'fand n-widths. We show that "most" subspaces are near-optimal, and show that convex optimization (Basis Pursuit) is a near-optimal way to extract information derived from these near-optimal subspaces

Compressed sensing

ContextDespite wide promulgation, clinical practice guidelines have had limited
effect on changing physician behavior. Little is known about the process and
factors involved in changing physician practices in response to guidelines.ObjectiveTo review barriers to physician adherence to clinical practice guidelines.Data SourcesWe searched the MEDLINE, Educational Resources Information Center (ERIC),
and HealthSTAR databases (January 1966 to January 1998); bibliographies; textbooks
on health behavior or public health; and references supplied by experts to
find English-language article titles that describe barriers to guideline adherence.Study SelectionOf 5658 articles initially identified, we selected 76 published studies
describing at least 1 barrier to adherence to clinical practice guidelines,
practice parameters, clinical policies, or national consensus statements.
One investigator screened titles to identify candidate articles, then 2 investigators
independently reviewed the texts to exclude articles that did not match the
criteria. Differences were resolved by consensus with a third investigator.Data ExtractionTwo investigators organized barriers to adherence into a framework according
to their effect on physician knowledge, attitudes, or behavior. This organization
was validated by 3 additional investigators.Data SynthesisThe 76 articles included 120 different surveys investigating 293 potential
barriers to physician guideline adherence, including awareness (n = 46), familiarity
(n = 31), agreement (n = 33), self-efficacy (n = 19), outcome expectancy (n
= 8), ability to overcome the inertia of previous practice (n = 14), and absence
of external barriers to perform recommendations (n = 34). The majority of
surveys (70 [58%] of 120) examined only 1 type of barrier.ConclusionsStudies on improving physician guideline adherence may not be generalizable,
since barriers in one setting may not be present in another. Our review offers
a differential diagnosis for why physicians do not follow practice guidelines,
as well as a rational approach toward improving guideline adherence and a
framework for future research.

https://www.ghdonline.org/uploads/Cabana_1999_JAMA_-_Why_dont_physicians_follow_clinical_practice_guidelines_-_a_framework_for_improvement.pdf

Why Don't Physicians Follow Clinical Practice Guidelines?: A Framework for Improvement

SUMMARY OF APPROACH The approach to surgery in the patient with COPD is summa-rized below. Surgery Definitely indicated Lung resection. Pulmonary function studies should be performedbefore lung resection. Simple spirometry has the greatest utilityin documenting physiologic operability. FEV, > 2 L in an adultman or > 60% of predicted is acceptable for pneumonectomy.Values below this suggest that further studies, such as split func-tion assessment by quantitative lung scintigraphy and exercisetesting, are warranted.FEV, predicted after lung resection to be less than 40 to 50%of normal for the patient’s sex, age, and height suggests highermorbidity and mortality. An exercise 90, of less than 10 to 15ml/min per kg of body weight is associated with higher mor-bidity and mortality after lung resection.All elective surgery Prophylaxis against deep venous throm-bosis should be given before most procedures that will requirepostoperative bed rest or significantly reduce mobility. Heparinin low doses seems well accepted for most procedures. Externalpneumatic compression of the lower legs can be used when anti-coagulants are contraindicated.

/pdf/standards-for-the-diagnosis-and-care-of-patients-with-13vz6fyao0.pdf

Standards for the Diagnosis and Care of Patients with Chronic Obstructive Pulmonary Disease

Identifying genetic correlations between complex traits and diseases can provide useful etiological insights and help prioritize likely causal relationships. The major challenges preventing estimation of genetic correlation from genome-wide association study (GWAS) data with current methods are the lack of availability of individual-level genotype data and widespread sample overlap among meta-analyses. We circumvent these difficulties by introducing a technique-cross-trait LD Score regression-for estimating genetic correlation that requires only GWAS summary statistics and is not biased by sample overlap. We use this method to estimate 276 genetic correlations among 24 traits. The results include genetic correlations between anorexia nervosa and schizophrenia, anorexia and obesity, and educational attainment and several diseases. These results highlight the power of genome-wide analyses, as there currently are no significantly associated SNPs for anorexia nervosa and only three for educational attainment.

/pdf/an-atlas-of-genetic-correlations-across-human-diseases-and-11fyqwnh4c.pdf

An atlas of genetic correlations across human diseases and traits.

Overweight and obesity affects more than 66% of the adult population and is associated with a variety of chronic diseases. Weight reduction reduces health risks associated with chronic diseases and is therefore encouraged by major health agencies. Guidelines of the National Heart, Lung, and Blood Institute (NHLBI) encourage a 10% reduction in weight, although considerable literature indicates reduction in health risk with 3% to 5% reduction in weight. Physical activity (PA) is recommended as a component of weight management for prevention of weight gain, for weight loss, and for prevention of weight regain after weight loss. In 2001, the American College of Sports Medicine (ACSM) published a Position Stand that recommended a minimum of 150 min wk(-1) of moderate-intensity PA for overweight and obese adults to improve health; however, 200-300 min wk(-1) was recommended for long-term weight loss. More recent evidence has supported this recommendation and has indicated more PA may be necessary to prevent weight regain after weight loss. To this end, we have reexamined the evidence from 1999 to determine whether there is a level at which PA is effective for prevention of weight gain, for weight loss, and prevention of weight regain. Evidence supports moderate-intensity PA between 150 and 250 min wk(-1) to be effective to prevent weight gain. Moderate-intensity PA between 150 and 250 min wk(-1) will provide only modest weight loss. Greater amounts of PA (>250 min wk(-1)) have been associated with clinically significant weight loss. Moderate-intensity PA between 150 and 250 min wk(-1) will improve weight loss in studies that use moderate diet restriction but not severe diet restriction. Cross-sectional and prospective studies indicate that after weight loss, weight maintenance is improved with PA >250 min wk(-1). However, no evidence from well-designed randomized controlled trials exists to judge the effectiveness of PA for prevention of weight regain after weight loss. Resistance training does not enhance weight loss but may increase fat-free mass and increase loss of fat mass and is associated with reductions in health risk. Existing evidence indicates that endurance PA or resistance training without weight loss improves health risk. There is inadequate evidence to determine whether PA prevents or attenuates detrimental changes in chronic disease risk during weight gain.

Appropriate Physical Activity Intervention Strategies for Weight Loss and Prevention of Weight Regain for Adults

Using data from the 1986 Adult Use of Tobacco Survey, we analyzed smoking-cessation methods used by adult smokers in the United States who tried to quit. About 90% of successful quitters and 80% of unsuccessful quitters used individual methods of smoking cessation rather than organized programs. Most of these smokers who quit on their own used a "cold turkey" approach. Multivariate analysis showed that women, middle-aged persons, more educated persons, persons who had made more quit-smoking attempts, and, particularly, heavier smokers were most likely to use a cessation program. Daily cigarette consumption, however, did not predict whether persons would succeed or fail during their attempts to quit smoking. Rather, the cessation method used was the strongest predictor of success. Among smokers who had attempted cessation within the previous 10 years, 47.5% of persons who tried to quit on their own were successful whereas only 23.6% of persons who used cessation programs succeeded. We conclude that cessation programs serve a small, but important, population of smokers that includes heavier smokers, those most at risk for tobacco-related morbidity and mortality. (JAMA. 1990;263:2760-2765)

Methods used to quit smoking in the United States. Do cessation programs help

Objective.—To assess the contribution of driver sleepiness to highway crashes and
review recent recommendations to change federal hours-of-service regulations
for commercial motor vehicle drivers.Data Sources.—Information was derived from a search of the MEDLINE, Transportation
Research Information Service (TRIS), and Bibliographic Electronic Databases
of Sleep (BEDS) databases from 1975 through 1997 and from manual review of
the reference lists in relevant journal articles, government publications,
conference proceedings, and textbooks.Data Synthesis.—Driver sleepiness is a causative factor in 1% to 3% of all US motor
vehicle crashes. Surveys of the prevalence of sleepy behavior in drivers suggest
that sleepiness may be a more common cause of highway crashes than is reflected
in these estimates. About 96% of sleep-related crashes involve passenger vehicle
drivers and 3% involve drivers of large trucks. Risk factors include youth,
shift work, alcohol and other drug use, over-the-counter and prescription
medications, and sleep disorders.Conclusions.—Increased awareness of the relationship between sleepiness and motor
vehicle crashes will promote the health and safety of drivers and highway
users. Physicians can contribute by encouraging good sleep habits, recognizing
and treating sleep-related problems, and counseling patients about the risks
of driving while sleepy. To protect public health and safety, the American
Medical Association recommends continued research on devices and technologies
to detect the signs of sleepiness and prevent the deterioration of driver
alertness and performance. Educational programs about the risks of falling
asleep while driving are needed for physicians, the public, and commercial
truck drivers.

Sleepiness, driving, and motor vehicle crashes

National trends in smoking prevalence by educational category from 1974 through 1985 show that education has replaced gender as the major sociodemographic predictor of smoking status. Smoking prevalence has declined across all educational groups but the decline has occurred five times faster among the higher educated compared with the less educated. From 1974 to 1985, smoking prevalence among persons with less than a high school diploma declined to 34.2% (0.19 percentage points per year) whereas prevalence for persons with four years or more of college education declined to 18.4% (0.91 percentage points per year). Smoking cessation activity increased across all educational groups, but the rate of increase among the higher educated was twice that of lower-educated groups. Initiation of smoking among more-educated men decreased rapidly to 15% in 1985 but leveled off by 1987. Until 1985, less-educated young females were the only group in which smoking initiation was increasing. However, in 1987 a sudden and large decline in initiation among less-educated females occurred. The apparent recent changes in initiation patterns by educational level suggest that the converging of smoking prevalence between the genders may not continue. The large and widening educational gap in smoking suggests that health promotion priorities need to be reassessed. ( JAMA 1989;261:56-60)

Trends in cigarette smoking in the United States. Educational differences are increasing.

Trends in the prevalence, initiation, and cessation of cigarette smoking are reported for the US population using weighted and age-standardized data from seven National Health Interview Surveys (1974 to 1985). The decline in prevalence was linear, with the prevalence for men decreasing at 0.91 percentage points per year to 33.5% in 1985 and the prevalence for women decreasing at 0.33 percentage points per year to 27.6% in 1985. For whites the rate of decline (percentage points per year) was 0.57, to 29.4% in 1985, and for blacks the decline was 0.67, to 35.6% in 1985. Smoking cessation increased among all gender-race groups from 1974 to 1985, with the yearly rate of increase (in percentage points per year) about equivalent for blacks (0.75) and whites (0.77), while it was higher in women (0.90) than in men (0.67). Smoking initiation decreased among young men (-1.03), while it remained about the same in young women (+ 0.11). Initiation decreased at a more rapid rate in blacks (-1.02) than in whites (-0.35). We conclude that smoking prevalence is decreasing across all race-gender groups, although at a slower rate for women than men, and that differences in initiation, more than cessation, are primarily responsible for the converging of smoking prevalence rates among men and women. (JAMA1989;261:49-55)

Trends in cigarette smoking in the United States. The changing influence of gender and race.

Data from National Health Interview Surveys from 1974 through 1985 are used to project cigarette smoking prevalence to the year 2000. Smoking prevalence in the United States has declined at a linear rate since 1974. If this trend continues, in the year 2000,22% of the adult population (40 million Americans) will be smokers. By the year 2000, the major inequalities in prevalence will occur among educational categories. At least 30% of those who have not proceeded beyond a'high school education will be smokers, whereas less than 10% of college graduates will smoke. Among the other sociodemographic subgroups, smoking prevalence is expected to decrease by the year 2000 to 20% among men, to 23% among women, to 25% among blacks, and to 21% among whites. Between 1974 and 1985, approximately 1.3 million persons per year became former smokers, indicating considerable success in public health efforts to encourage people to stop smoking. However, in the early 1980s, approximately 1 million new young persons per year were recruited to the ranks of regular smokers. This is equivalent to about 3000 new smokers each day. Public health efforts need to focus more on preventing young people from starting to smoke, and such prevention efforts should particularly target less educated socioeconomic groups. ( JAMA 1989;261:61-65)

Ronald M. Davis

Papers

Methods used to quit smoking in the United States. Do cessation programs help

Sleepiness, driving, and motor vehicle crashes

Trends in cigarette smoking in the United States. Educational differences are increasing.

Trends in cigarette smoking in the United States. The changing influence of gender and race.

Trends in cigarette smoking in the United States. Projections to the year 2000.