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D S Main

Publications and source records attributed to D S Main.

At least 19 recordsLinked to original sources
PubMed2006

Double layers and ion phase-space holes in the auroral upward-current region.

The dynamic evolution of the boundary between the ionosphere and auroral cavity is studied using 1D and 2D kinetic Vlasov simulations. The initial distributions of three singly ionized species (H+, O+, e-) are determined from space-based observations on both sides of an inferred strong double layer. The kinetic simulations reproduce features of parallel electric fields, electron distributions, ion distributions, and wave turbulence seen in satellite observations in the auroral upward-current region and, for the first time, demonstrate that auroral acceleration can be driven by a parallel electric field supported, in part, by a quasistable, strong double layer. In addition, the simulations verify that the streaming interaction between accelerated O+ and H+ populations continuously replenished by the double layer provides the free energy for the persistent formation of ion phase-space holes.

Journal Article↗
PubMed2005

Initial validation of an instrument to identify barriers to self-management for persons with co-morbidities.

OBJECTIVE: To develop and initially validate a questionnaire designed to assess barriers to self-management perceived by persons with multiple chronic medical conditions. We hypothesized that persons who reported increased barriers to self-management would also report lower general health status and a greater disease burden. METHODS: A cross-sectional survey was done of Health Maintenance Organization members aged 65 years or older with varying numbers of chronic medical conditions. On the basis of a previous qualitative investigation, we have identified 13 domains representing potential barriers to self-management. We developed questions to assess each of these domains and, for each, calculated coefficients alpha and assessed correlation of that domain with self-reported general health status and disease burden. RESULTS: Respondents reported an average of 5.9 chronic conditions. Eight domains demonstrated acceptable internal consistency in this population. Nine of 13 domains correlated significantly in the expected direction with health status and/or disease burden. DISCUSSION: These results provide an encouraging first step in developing a tool that will be clinically useful in assessing and addressing barriers to medical self-management for persons with co-morbidities. Use of assessments such as this in clinical settings may facilitate appropriate and efficient care management and improved health outcomes for this growing and vulnerable patient population.

Aged↗
PubMed2001

Student perspectives on primary care preceptorships: enhancing the medical student preceptorship learning environment.

BACKGROUND: Medical students participate in a longitudinal (3-year) primary care preceptorship to assist them in developing skills in interviewing and examining patients in an ambulatory care setting. PURPOSE: To identify from a student's perspective important context and process issues in a longitudinal preceptorship. METHODS: The investigators used an "editing" style of analysis to identify significant themes across 24 medical student focus groups held between October 1995 and December 1997. RESULTS: Significant themes emerged from the data analysis that describe important features of what makes the preceptorship work for students. The main themes are active teaching, active learning, a trusting relationship, sufficient time, and a shared understanding of preceptorship objectives. The potential benefits to students in an enhanced learning environment are comfort, confidence, responsibility, skills, knowledge, reinforcement, learning opportunities, teaching opportunities, and models for practice. CONCLUSIONS: We offer recommendations for enhancing longitudinal preceptorships for preceptors, students, and leaders in medical education.

Attitude of Health Personnel↗
PubMed2001

The effect of families on the process of outpatient visits in family practice.

OBJECTIVES: Our goal was to describe how physician knowledge of patients' families affects the processes of patient care in family practices. STUDY DESIGN: Using a multimethod comparative case study design, detailed dictated field notes were recorded after direct observation of patient encounters and the office environment as part of the Prevention and Competing Demands in Primary Care Study. We identified domains of outpatient visits in which patients were accompanied by a family member or in which family-oriented content was discussed. POPULATION: Outpatient encounters with 1637 patients presenting in 18 family practices in the Midwest were analyzed using an editing style. OUTCOMES: We developed a typology for ways in which family context affects outpatient visits. RESULTS: Patients were accompanied during 35% of all outpatient visits, the vast majority of these visits involving children. Family history or a family member's problems were discussed during 35% of visits during which no family member was present. An analysis of these "family-oriented" visits resulted in a typology of 6 ways that family context informs and affects the outpatient visit: (1) using family social context to illuminate patient disease, illness, and health; (2) using family to discover the source of an illness; (3) discussing and managing the health and illness of family members; (4) family concern for patient's health; (5) using the family as a care resource and care collaborator; and, (6) giving family members unscheduled care. CONCLUSION: Family context is an important feature of family practice that influences the processes of patient care. Since family-oriented care is an essential feature of family practice, outcomes of this largely hidden part of care deserve further study.

Adult↗
PubMed1999

The family physician and house calls. A survey of Colorado family physicians.

BACKGROUND: Visiting patients at home has long been one of the activities of the family physician, but the practice of making house calls has diminished significantly during the second half of the 20th century. The goal of this study was to describe physicians' attitudes about house calls and their practice of making them in the rapidly changing health care environment of the United States. METHODS: A 30-item, self-administered questionnaire was designed to obtain demographic information about physicians and their attitudes toward house calls, practice experiences with making house calls, and any additional factors that influence making house calls. It was mailed to all members of the Colorado Academy of Family Physicians, during the summer of 1997. RESULTS: A 66% response rate was obtained from practicing physicians. Overall attitudes toward house calls were positive. Fifty-three percent of the respondents reported making house calls, and 8% reported making more than 2 house calls per month. Male physicians, those older than 40 years, those in rural settings, and those trained in a community-based residency were more likely to make house calls. Patient payer mix and practice setting were also related to whether a physician made house calls. House calls were most frequently made to geriatric patients, cancer patients, trauma patients, and patients with transportation difficulties. Many physicians reported using home health agencies for assessment and treatment of patients needing home care. CONCLUSIONS: Family physicians agree that house calls are good for patients. More than half of the respondents reported that they occasionally make house calls. However, few physicians routinely perform house calls.

Adult↗
PubMed1996

Toward optimal laboratory use. Problems in laboratory testing in primary care.

OBJECTIVE: To examine the frequency and characteristics of problems in laboratory testing in primary care physicians's offices and their impact on health care. DESIGN: Prospective descriptive study in which participating office-based primary care clinicians reported each occurrence of any laboratory incident during a 6-month study. Each identified problem was reported on a structured data collection instrument with an open-ended description of the problem. SETTING: Primary care physicians' offices in North America. PARTICIPANTS: One hundred twenty-four primary care clinicians in 49 practices of the Ambulatory Sentinel Practice Network (ASPN). MAIN RESULTS: A total of 180 problems were reported, yielding a crude rate of 1.1 problems per 1000 patient visits. Problems involving test ordering and specimen handling were the most common (56%), while those attributable to the test analysis itself accounted for 13% of the total. In the judgment of the practice staff, 27% of the reported problems had an impact on patient care. Of the 24 cases for which the specific impact was known and reported, half of the impacts were minor and about half were significant, as judged by whether or not the diagnosis and/or treatment of the patient was measurably affected. CONCLUSIONS: Clinically apparent problems with laboratory testing in primary care were found at a rate of 1.1 problems per 1000 patient visits. Of the laboratory problems that occurred in this study, 27% were judged by the physician to have an effect on patient care.

Clinical Laboratory Techniques↗
PubMed1996

Matching anonymous pre-posttests using subject-generated information.

Sensitive research issues call for anonymous questionnaires. This makes accurately matching pretests with posttests difficult or impossible. Various subject-generated coding schemes have been developed, but their accuracy has been unknown. This anonymous study, with 745 students, used subject-generated coding to match pretests with posttests. The matching was verified for accuracy with the use of a collateral, anonymous, sticker identification system. The coding system was able to accurately match 75.2% of all the pretest-posttest pairs. An additional 22.1% of the pairs were left unmatched and only 2.7% were matched incorrectly. Subject-generated coding systems can be very effective where confidentiality is important to protect.

Adolescent↗
PubMed1995

Human immunodeficiency virus seroprevalence in community-based primary care practices, 1990-1992. A report from the Ambulatory Sentinel Practice Network.

OBJECTIVE: To estimate the seroprevalence of human immunodeficiency virus type 1 (HIV-1) infection in primary care practices. METHODS: Fifty-four practices in the United States participated in an anonymous, unlinked HIV seroprevalence study between January 1990 and December 1992. Residual blood samples drawn for routine clinical tests from patients 15 to 49 years of age were centrally tested for the HIV-1 antibody for 1 month of each quarter. Information about patient demographics, clinician-recognized risk factors, the known HIV status of the patient, and whether the blood was drawn for HIV testing was recorded with each specimen. RESULTS: Of 21,998 specimens collected, 99 (0.45%) were seropositive. Of these 99 seropositive persons, 31.3% (a seroprevalence of 0.15%) were not suspected by their clinicians of being infected with HIV. Seroprevalences in men (0.96%) exceeded those in women (0.22%), and rates in rural practices (0.18%) were lower than in urban practices (0.71%). Among patients with unsuspected HIV infection, however, the gender differences, especially in rural areas, were less pronounced. Risk factors for HIV infection were infrequently noted. There was an increase in the overall seroprevalence during the 1990 to 1992 study period (0.36% to 0.53%); however, this trend was not statistically significant. CONCLUSIONS: Within a 3-year period, clinicians in at least two of five primary care practices can expect to encounter patients infected with HIV, regardless of practice location. Also, nearly one third of the patients with HIV infection will not be suspected of having this condition by their clinician.

Adolescent↗
PubMed1994

Preventing HIV infection among adolescents: evaluation of a school-based education program.

BACKGROUND: This article reports the results of the impact of a school-based HIV prevention intervention on students' knowledge, attitudes, and behavior related to HIV infection. METHODS: Seventeen schools within six Colorado school districts were assigned to either intervention or comparison conditions. Students in 10 schools received a 15-session, skills-based HIV prevention curriculum implemented by trained teachers. A total of 2,844 students completed at least one survey during the study period; surveys were matched using demographic questions, yielding a cohort of 979 students who had baseline and 6-month follow-up data. RESULTS: Intervention students exhibited greater knowledge about HIV and greater intent to engage in safer sexual practices than the comparison students. Among sexually active students at the 6-month follow-up, intervention students reported fewer sexual partners within the past 2 months, greater frequency of using condoms, and greater intentions to engage in sex less frequently and to use a condom when having sex. Intervention students were also more likely to believe that teens their age who engage in HIV risk behaviors are vulnerable to infection. The intervention neither delayed the onset nor decreased the frequency of sexual intercourse and the frequency of alcohol and other drug use before sex by the 6-month follow-up assessment. CONCLUSIONS: The results suggest that skills-based risk reduction programs can have an effect on student behavior. Among sexually active students, evidence suggests that school-based interventions can reduce behavior associated with risk of HIV infection.

Adolescent↗
PubMed1993

The role of primary care clinician attitudes, beliefs, and training in the diagnosis and treatment of depression. A report from the Ambulatory Sentinel Practice Network Inc.

OBJECTIVE: To examine the relation between primary care clinicians' attitudes, beliefs, and training and their perceptions of the importance and frequency of depression. DESIGN: A 56-item questionnaire was mailed to 226 clinicians in the Ambulatory Sentinel Practice Network Inc (ASPN), a primary care research network. SETTING: The ASPN, consisting of 69 primary care practices in the United States and Canada, cares for approximately 350,000 patients. MAIN OUTCOME MEASURE: The degree to which clinician training in depression and clinician attitudes and beliefs about treating depression predict their perceptions of the importance of depression in their primary care practices. RESULTS: Results of path analysis indicate that clinician training in depression, beliefs about the burden and discomfort associated with diagnosing and treating depression, perceptions of their patients' discomfort, and self-efficacy in diagnosing and treating depression are all significantly related to clinician perceptions of whether depression was an important and frequent primary care problem. Further analysis indicates that actual prevalence of depression accounted for little variability in clinicians' beliefs and attitudes about depression. CONCLUSIONS: What clinicians think their patients feel about issues on depression and how they view their own abilities may profoundly influence the degree to which they recognize depression in primary care. Understanding these factors may help explain and subsequently decrease clinician variability in the recognition of depression in primary care.

Attitude of Health Personnel↗
PubMed1993

Frequency of exercise and dropouts in a work-site program. Correlates of 6-month activity patterns.

Exercise professionals have little information concerning expected levels of exercise for new participants. This study examined the frequency of exercise of 949 employees during their first 6 months of membership in a work-site health promotion facility, using automated check-in data. Overall, the frequency of exercise declined, the proportion of frequent exercisers declined, and the proportion of employees who dropped out increased. Men exercised more frequently and were less likely to drop out than were women (P < .01). Younger employees exercised more frequently than did older employees. Employees in the middle salary level exercised more frequently than did employees in the lower or upper levels (P < .01). The employee groups that started out with a lower frequency of exercise remained at a lower frequency throughout the 6 months. By their 6th month, women were 50% more likely to drop out and 50% less likely to exercise regularly than were men. These figures provide a basis for comparison with other programs to document expected exercise behavior.

Adult↗
PubMed1993

Factors influencing mammogram ordering at the time of the office visit.

BACKGROUND: Breast cancer is the second most common cause of cancer death in women, with mammographic screening the only modality shown to decrease the death rate. However, only 17% to 41% of women have ever been screened, and multiple barriers to screening have been identified. This study examined physician and patient factors at a single encounter to explore components influencing mammography ordering. METHODS: Ten family physicians in a primary care research network completed daily data cards on encounters with women presenting for annual examinations, chronic problems, or breast-related complaints. Information collected included patient age, personal or family history of breast cancer, physician's perception of expected compliance, previous mammogram results, breast examination, physician's perception of need for a mammogram, whether the mammogram was ordered, and the patient's method of payment for the test. RESULTS: Eight hundred thirty-nine patients were entered into the study, and 277 mammograms were ordered. Mammograms were ordered for a greater percentage of patients with insurance (36%) than for those without insurance (26%) (P < .001). A multivariate analysis indicated that several factors helped to correctly classify 90% of mammogram ordering: the patient was making a first visit, a breast-related visit, or a visit for an annual examination; the patient had had a previous mammogram; had a breast examination at the current visit or within the past year; and the physician believed the patient would comply and believed that a mammogram was indicated. CONCLUSIONS: Factors unique to a physician-patient visit influence the physician with regard to ordering a mammogram, including the type of visit, whether the physician believes a mammogram is indicated, and the cost.

Adult↗
PubMed1992

Patients presenting to family physicians after a fall: a report from the Ambulatory Sentinel Practice Network.

BACKGROUND: Patients who fall present a diagnostic challenge to family physicians. The diagnostic workup of these patients must be thorough enough to detect and treat important causes of the fall yet not subject patients to unnecessary tests. Previous studies have provided only limited guidance for primary care physicians because in general they occurred in settings other than primary care and focused on a single age group. METHODS: The Ambulatory Sentinel Practice Network (ASPN) conducted a 6-month study of primary care patients of all ages presenting after a fall, or with medical problems resulting from a fall. ASPN clinicians collected information about the history, physical examination findings, and follow-up of these patients. Causes of falls were grouped into three categories: external reasons for falling, internal reasons related to gait, and internal reasons unrelated to gait. RESULTS: Participating clinicians identified 431 patients who had falls out of the 256,680 seen for any reason during the study period. The patients ranged in age from 1 to 94 years. The rate of falls for patients increased rapidly after age 65 years. Most falls occurred for reasons external to the patient, but internal reasons, both nonlocomotor and locomotor, increased after age 65 years. No nonlocomotor causes for a fall were found in patients younger than 65 years of age. Also, the rate of hospitalization of patients seen for falls was greater in the geriatric age group. CONCLUSIONS: The results highlight the need for further research about falls, particularly those occurring in pediatric and young adult patients. Furthermore, correcting environmental hazards and modifying gait problems in the elderly by increasing lower extremity and truncal strength could decrease the risk of falling.

Accidental Falls↗
PubMed1989

A subsidized perinatal care program in a rural Colorado county.

A large number of medically indigent women in rural areas currently receive little or no prenatal care, raising major concerns regarding perinatal health. In Colorado, subsidized prenatal and labor/delivery programs have been instituted to address this problem. This article describes the implementation of two programs in one rural county. In these rural programs, private physicians, health department personnel, and social work staff at the local hospital collaborate to provide financial assistance, comprehensive health education, and quality medical care for eligible pregnant women. The identified benefits and barriers unique to the provision of quality perinatal care in rural settings are discussed.

Colorado↗
PubMed1988

Children's preference for challenge: the role of perceived competence and control.

This research tested the hypothesis that children's perceptions of academic competence and their personal control over school-related performance affects subsequent intrinsic interest and preference for challenge in an evaluative setting. In a correlational study, children's self-reported perceptions of academic competence and personal control were found to relate positively to their intrinsic interest in schoolwork and preference for challenging school activities. A subset of this sample was exposed to varying levels of a controlling directive, and preference for challenge was assessed behaviorally during a free-choice period in which subjects were unaware that they were being observed. As predicted, the data indicated that when given the evaluative, controlling directive, children who had high perceptions of academic competence and control preferred a greater challenge than did children whose perceptions were low on these measures. No difference between groups in terms of preference for challenge was evident when no controlling directive was presented. These findings are discussed in terms of theories of intrinsic motivation and potential processes that underly these effects.

Achievement↗
PubMed1986

Enhancing interest in peer interaction: a developmental analysis.

Using an intrinsic motivation paradigm, the effects of providing different reasons for interacting with a peer were examined in terms of children's subsequent interest in playing with the other child. Children (5 1/2, 7, and 9 years old) were randomly assigned to 1 of 3 conditions and provided with identical information about a child presented on a television monitor (that he was nice and had a new Lego game). In the experimental conditions, children were then asked if they wanted to play with the peer either "because he has a new game" (situational information) or "because he's real nice" (dispositional information). The results indicated that, for the 9-year-olds, the dispositional/intrinsic information enhanced subsequent intrinsic interest in the peer relative to the control condition, while the situational information undermined later interest. In contrast, for the younger age groups, the situational information increased interest in peer interaction for the younger age groups in comparison to the control condition, while the dispositional information did not differ from control. The findings are discussed in terms of potential processes underlying these effects.

Child↗
PubMedDate not supplied

The inadequacy of using means to compare medical costs of smokers and nonsmokers.

The costs associated with health risks have become a primary focus in the field of health promotion. Unfortunately, the nature and quality of medical cost data are not ideal for simple comparisons of health risk groups. Most health promotion professionals have had little or no training on how to interpret cost data and are thus unaware of the limitations and problems inherent in cost comparisons. This report illustrates the problems encountered when using cost data, using examples from a medical claims dataset. Specifically, the potential errors that result from comparing group means are shown. A set of alternatives for practitioners and researchers to consider when comparing costs for different groups are offered.

Adolescent↗