Notes on density matrix perturbation theory.

Density matrix perturbation theory (DMPT) is known as a promising alternative to the Rayleigh-Schrödinger perturbation theory, in which the sum-over-states (SOS) is replaced by algorithms with perturbed density matrices as the input variables. In this article, we formulate and discuss three types of DMPT, with two of them based only on density matrices: the approach of Kussmann and Ochsenfeld [J. Chem. Phys. 127, 054103 (2007)] is reformulated via the Sylvester equation and the recursive DMPT of Niklasson and Challacombe [Phys. Rev. Lett. 92, 193001 (2004)] is extended to the hole-particle canonical purification (HPCP) from Truflandier et al. [J. Chem. Phys. 144, 091102 (2016)]. A comparison of the computational performances shows that the aforementioned methods outperform the standard SOS. The HPCP-DMPT demonstrates stable convergence profiles but at a higher computational cost when compared to the original recursive polynomial method.

Characterizing a "Big Data" Cohort of Over 200,000 Low-Income U.S. Infants and Children for Obesity Research: The ADVANCE Early Life Cohort.

Introduction Low-income populations have elevated exposure to early life risk factors for obesity, but are understudied in longitudinal research. Our objective was to assess the utility of a cohort derived from electronic health record data from safety net clinics for investigation of obesity emerging in early life. Methods We examined data from the PCORNet ADVANCE Clinical Data Research Network, a national network of Federally-Qualified Health Centers serving >1.7 million safety net patients across the US. This cohort includes patients who, in 2012-2014, had ≥1 valid body mass index measure when they were 0-5 years of age. We characterized the cohort with respect to factors required for early life obesity research in vulnerable subgroups: sociodemographic diversity, weight status based on World Health Organization (<2 years) or Centers for Disease Control (≥2 years) growth curves, and data longitudinality. Results The cohort includes 216,473 children and is racially/ethnically diverse (e.g., 17.9% Black, 45.4% Hispanic). A majority (56.9%) had family incomes below the Federal Poverty Level (FPL); 32% were <50% of FPL. Among children <2 years, 7.6 and 5.3% had high and low weight-for-length, respectively. Among children 2-5 years, 15.0, 12.7 and 2.4% were overweight, obese, and severely obese, respectively; 5.3% were underweight. In the study period, 79.2% of children had ≥2 BMI measures. Among 4-5 year olds, 21.9% had >1 BMI measure when they were <2 years. Discussion The ADVANCE Early Life cohort offers unique opportunities to investigate early life determinants of obesity in the understudied population of low income and minority children.

Communication: Generalized canonical purification for density matrix minimization.

A Lagrangian formulation for the constrained search for the N-representable one-particle density matrix based on the McWeeny idempotency error minimization is proposed, which converges systematically to the ground state. A closed form of the canonical purification is derived for which no a posteriori adjustment on the trace of the density matrix is needed. The relationship with comparable methods is discussed, showing their possible generalization through the hole-particle duality. The appealing simplicity of this self-consistent recursion relation along with its low computational complexity could prove useful as an alternative to diagonalization in solving dense and sparse matrix eigenvalue problems.

Characteristics of medical students by level of interest in family practice.

BACKGROUND AND OBJECTIVES: This study provides information on student factors associated with a career choice in family practice. METHODS: Information was used from multiple surveys completed by medical students, including the Premedical Questionnaire, the Matriculating Student Questionnaire, and the Graduation Questionnaire, as well as information from residency directors about residents in the Graduate Medical Education Tracking Census. These questionnaires are all a part of the Student and Applicant Information Management System of the Association of American Medical Colleges. Participants were 30,789 students graduating from US medical schools in 1991 and 1992. Comparisons were made between longitudinal student responses on the surveys to four types of outcomes. RESULTS: A total of 1,029 (3.3%) students were in the "Maintained" group (students who originally planned to enter family practice and were in a family practice residency at postgraduate year 1; 1,958 (6.4%) were "Gained" (originally chose a specialty other than family practice but entered a family practice residency); 1,950 (6.3%) were "Lost Interest" (originally identified family practice but entered another residency-two thirds of whom selected non-primary care specialties); 21,573 (70.1%) were "Never Interested" (did not express an early interest nor select a family practice residency); and the remainder (13.9%) had incomplete specialty data. Of those originally interested in family practice, 34.5% entered family practice residencies. Only 8.3% of those not originally interested entered family practice residencies. The four groups of students differed on many demographic, attitudinal, and experiential characteristics. Prestige, income, opportunities for research, and faculty status were more important to future specialists, while emphasis on primary care and prevention and practice in smaller communities were more important to the future family physicians. CONCLUSIONS: Medical schools could potentially increase the number of students selecting family practice residencies through both admissions policies and medical school experiences. These data provide some specifics on how to recruit students and prevent loss of those originally interested in family practice.

Matching physician supply and requirements: testing policy recommendations.

Managed care has been growing and likely will increase market share. This movement will require fundamental alterations in the number and specialty distribution of physicians. Under current production, future supply does not appear well-matched with requirements. Although the adequacy of generalist supply is of concern, the oversupply of specialists is the overriding problem. Neither reducing the number of first-year residents nor increasing the generalist output alone would bring both generalist and specialist supply within requirement ranges. Combining an increase in generalist production to 50% with a reduction in first-year residents to 110% of the number of U.S. medical graduates would minimize the projected specialty surplus while maintaining generalist supply within the requirement range.

Where there is no family doctor: the development of family practice around the world.

Family physicians are generalists trained at the postgraduate level to address the majority of primary care needs of patients of all ages in communities they serve. Throughout the world there is a need for family physicians to serve as cornerstones of comprehensive health care systems that provide high-quality, cost-effective medical and public health services to the entire population. To meet this need, each country must value and adequately finance essential medical and public health services and must provide family physicians with a thorough education focused on the relevant health care problems of the population being served. The authors present an overview of the status of this training throughout the world, outline challenges to the development of such training, and suggest strategies for successful development accompanied by illustrative case studies from South Korea, Venezuela, and Pakistan.

State legislative strategies to improve the supply and distribution of generalist physicians, 1985 to 1992.

State laws enacted between 1985 and 1992 were reviewed to examine state involvement in influencing the supply and distribution of generalist physicians. Forty-seven states enacted 238 relevant laws during this period. In 1991 and 1992, 36 states enacted 98 laws, as compared with 1985 and 1986, when 8 states enacted 12 laws. Legislation addressed planning and oversight; financial incentives to institutions, students, and residents; and strategies to enhance the practice environment. A new strategy is to link funding to measureable outcomes, such as the career choices of a state medical school's graduates. Few states devoted resources to evaluate their efforts.

Cancer prevention behaviors among African-American adults: a survey of wards 7 and 8 in Washington, DC.

A telephone survey of knowledge, attitude, and health practices regarding cancer was undertaken in wards 7 and 8, Washington, DC in 1988. These wards have the highest cancer rates in the city and are predominantly African American. Of the 670 randomly selected persons over 18 years of age, 243 were males and 427 were females. Among females, 84% believed cigarette smoking causes cancer, and 48% thought alcohol causes cancer; 31% smoked cigarettes and 38% consumed alcoholic beverages. Among males, 91% and 52% thought cigarettes and alcohol causes cancer respectively; 41% smoked and 54% consumed alcoholic beverages. Only 6% of the males over age 40 practiced all eight recommended cancer prevention behaviors, while 2% of the females over age 40 practiced all preventive health behaviors. Cancer preventive behavior was examined in relation to socioeconomic status. This study indicates that preventive health behaviors were not associated with socioeconomic status. Data suggest that cancer prevention and control programs and services targeted to this Washington, DC population should be increased and intensified.

Managed care on the march: will physicians meet the challenge?

The health care delivery system in the United States is in transition. Increasingly managed care plans are gaining in predominance. The proliferation of managed care systems will have an impact on the demand and requirements for physicians. This paper attempts to project and estimate requirements for physicians in 2000 and 2020, assuming that the health care system will continue to be dominated by managed care. The projections are then compared to forecasts of physician supply under two separate physician production scenarios. The authors discuss the adequacy of the future physician workforce to provide services required by a health care system dominated by managed care.

Defining the generalist physician's training.

OBJECTIVE: To determine the extent to which various specialties prepare residents in the broad competencies required for primary care practice and to propose guidelines for improving generalist physician training. DATA SOURCES: Leading causes of morbidity and mortality, 1991 National Ambulatory Medical Care Survey data, expert reports, and the special requirements for residency training. DESIGN: From the data sources we identified the common presenting conditions and diagnoses that broadly trained generalist physicians could be expected to manage in primary care practice. We then compiled a list of 60 requisite residency training components grouped according to seven practice criteria for generalist physicians. Using the special requirements for residency training for family practice, internal medicine, pediatrics, obstetrics and gynecology, and emergency medicine, we determined the extent to which the requirements addressed the 60 components and continuity-of-care training. RESULTS: Almost all of the 60 generalist training components were required by family practice (95%), internal medicine (91%), and pediatrics (91%), compared with emergency medicine (42%) and obstetrics and gynecology (47%). Family practice, internal medicine, and pediatric residencies also require lengthy, well-defined continuity-of-care experiences. CONCLUSION: Family practice, internal medicine, and pediatric programs prepare residents in the broad competencies necessary for primary care practice. To train competent generalist physicians, we recommend that residency programs require training in 90% or more of the 60 components, 50% or more of the components in each of the seven categories, and a continuity-of-care experience for a panel of patients during at least 10% of the entire residency training period.

Medical education about substance abuse: changes in curriculum and faculty between 1976 and 1992.

PURPOSE: To examine changes in substance abuse education in U.S. medical schools between 1976 and 1992. METHODS: In 1991-92 the authors conducted a 16-year follow-up survey of six clinical departments in each of the 126 U.S. medical schools. Two previous surveys by scholars and surveys conducted by the Liaison Committee on Medical Education, Association of American Medical Colleges, and the National Center for Medical Fellowships in the Addictions provided baseline data for comparison. The statistical methods used in the comparisons were paired t-tests, one-way analyses of variance, and tests of differences between proportions. RESULTS: Significant increases were found in the numbers of required and elective curriculum units for medical students between 1986-87 and 1991-92. The number of medical schools requiring courses in substance abuse treatment increased from five to eight between 1986-87 and 1991-92. For residents, there were significant increases in the numbers of curriculum units for residents in family medicine and pediatrics. The average number of faculty in the 116 medical schools that reported units on substance abuse was 4.1. There were 45 fellowships in addiction medicine identified in 1991-92, with a total of 61 fellows in training. CONCLUSION: While the findings confirm positive changes, the amount of curricula time and the number of faculty having expertise in substance abuse education do not compare well with the amounts of time and numbers of faculty involved in clinical problems of similar prevalence, such as cancer and heart disease.

Faculty development in addiction medicine: project SAEFP, a one-year follow-up study.

BACKGROUND AND OBJECTIVES: The goal of Project SAEFP (Substance Abuse Education for Family Physicians, pronounced SAFE) was to increase the number of residency teaching faculty with expertise in addiction medicine. This paper reports the results of a 12-month follow-up study conducted to assess changes in residency teaching and clinical practice of 165 residency teaching faculty who participated in this project. METHODS: The Project SAEFP work group conducted a series of 5-day courses in the fall of 1990 at 10 sites around the country. The 165 faculty participants were taught how to use a set of 12 residency teaching modules that focused on clinical areas important to primary care physicians. The follow-up study consisted of a structured telephone interview. The findings were compared to previous interviews conducted before, and 3 months after, faculty participation in the course. RESULTS: The findings suggest long-term increases in the amount of teaching, clinical practice, and consultations conducted by the family medicine faculty who participated in this faculty development project. CONCLUSION: The findings of this study suggest that an intensive 5-day course using learner-centered teaching techniques can have a significant impact on primary care teaching faculty.