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John M Harris

Publications and source records attributed to John M Harris.

8 recordsLinked to original sources
PubMed2006

A stable isotope aridity index for terrestrial environments.

We use the oxygen isotopic composition of tooth enamel from multiple mammalian taxa across eastern Africa to present a proxy for aridity. Here we report tooth enamel delta(18)O values of 14 species from 18 locations and classify them according to their isotopic sensitivity to environmental aridity. The species are placed into two groups, evaporation sensitive (ES) and evaporation insensitive (EI). Tooth enamel delta(18)O values of ES animals increase with aridity, whereas the tooth enamel delta(18)O values of EI animals track local meteoric water delta(18)O values, demonstrating that bioapatite delta(18)O values of animals with different behaviors and physiologies record different aspects of the same environment. The enrichment between tooth enamel delta(18)O values of ES and EI animals records the degree of (18)O enrichment between evaporated water (ingested water or body water) and source water, which increases with environmental aridity. Recognition of the ES-EI distinction creates the opportunity to use the (18)O composition of bioapatite as an index of terrestrial aridity.

Animals↗
PubMed2006

A tool for measuring physician readiness to manage intimate partner violence.

BACKGROUND: Intimate partner (domestic) violence (IPV) is a common problem in medical practice that is associated with adverse health outcomes. There are widespread calls to improve IPV education for physicians, but there are few valid, reliable, easily available, and comprehensive measures of physician IPV knowledge, attitudes, and practices that can be used to assess training effectiveness. METHODS: In 2002, expert consensus and previous surveys were used to develop a new survey-based IPV self-assessment tool that included more information on current IPV knowledge and practices than previous tools. The draft tool was evaluated using standard psychometric techniques in a group of 166 physicians in 2002, revised, and then retested in a second group of 67 physicians on three occasions in 2003 and 2004. Analyses were conducted in 2005. RESULTS: The draft IPV survey tool demonstrated good internal consistency reliability, with Cronbach's alpha >/=0.65 for ten final scales. The developed scales were closely correlated with theoretical constructs and predictive of self-reported behaviors. On repeat testing, a revised version of the tool was found to have good stability of psychometric properties in a different physician population (Cronbach's alpha>/=0.65, and internal correlations as predicted), good correlation with measured office IPV practices, and stable results in this population over 12 months. CONCLUSIONS: The final version of this instrument, named the PREMIS (Physician Readiness to Manage Intimate Partner Violence Survey) tool, is a 15-minute survey that is a comprehensive and reliable measure of physician preparedness to manage IPV patients. This tool is publicly available and can be used to measure the effectiveness of IPV educational programs.

Attitude of Health Personnel↗
PubMed2006

A community-based trial of an online intimate partner violence CME program.

BACKGROUND: There is a broad need to improve physician continuing medical education (CME) in the management of intimate partner violence (IPV). However, there are only a few examples of successful IPV CME programs, and none of these are suitable for widespread distribution. DESIGN: Randomized controlled trial beginning in September 2003 and ending in November 2004. Data were analyzed in 2005. SETTING/PARTICIPANTS: Fifty-two primary care physicians in small (fewer than eight physicians), community-based medical offices in Arizona and Missouri. INTERVENTION: Twenty-three physicians completed a minimum of 4 hours of an asynchronous, multi-media, interactive, case-based, online CME program that provided them flexibility in constructing their educational experience ("constructivism"). Control physicians received no CME. MAIN OUTCOME MEASURES: Scores on a standardized self-reported survey, composed of ten scales of IPV knowledge, attitudes, beliefs, and self-reported behaviors (KABB) administered before randomization and repeated at 6 and 12 months following the CME program. RESULTS: Use of the online CME program was associated with a significant improvement in eight of ten KABB outcomes, including physician self-efficacy and reported IPV management practices, over the study period. These measures did not improve in the control group. CONCLUSIONS: The Internet-based CME program was clearly effective in improving long-term individual educational outcomes, including self-reported IPV practices. This type of CME may be an effective and less costly alternative to live IPV training sessions and workshops.

Clinical Competence↗
PubMed2005

Carbon starvation in glacial trees recovered from the La Brea tar pits, southern California.

The Rancho La Brea tar pit fossil collection includes Juniperus (C3) wood specimens that 14C date between 7.7 and 55 thousand years (kyr) B.P., providing a constrained record of plant response for southern California during the last glacial period. Atmospheric CO2 concentration ([CO2]) ranged between 180 and 220 ppm during glacial periods, rose to approximately 280 ppm before the industrial period, and is currently approaching 380 ppm in the modern atmosphere. Here we report on delta13C of Juniperus wood cellulose, and show that glacial and modern trees were operating at similar leaf-intercellular [CO2](ci)/atmospheric [CO2](ca) values. As a result, glacial trees were operating at ci values much closer to the CO2-compensation point for C3 photosynthesis than modern trees, indicating that glacial trees were undergoing carbon starvation. In addition, we modeled relative humidity by using delta18O of cellulose from the same Juniperus specimens and found that glacial humidity was approximately 10% higher than that in modern times, indicating that differences in vapor-pressure deficits did not impose additional constrictions on ci/ca in the past. By scaling ancient ci values to plant growth by using modern relationships, we found evidence that C3 primary productivity was greatly diminished in southern California during the last glacial period.

Atmosphere↗
PubMed2005

Body size of Smilodon (Mammalia: Felidae).

The body masses of the three large saber-toothed machairodontines, Smilodon gracilis, S. fatalis, and S. populator, were estimated on the basis of 36 osteological variables from the appendicular skeleton of extant felids. A new model is introduced that takes the reliability of the predictor equations into account, since mass estimates are more reliable when computed from multiple variables per bone. At a body mass range of 55-100 kg, S. gracilis was comparable in size to extant jaguars, and S. fatalis was found to be somewhat lighter than previously assumed, with a body mass range of 160-280 kg, similar to that of the largest extant felid, the Siberian tiger. Smilodon populator was substantially heavier and larger than any extant felid, with a body mass range of 220-360 kg. Particularly large specimens of S. populator almost certainly exceeded 400 kg in body mass. The differences from previous estimates are most likely caused by differences in the databases used for mass estimation.

Animals↗
PubMed2003

Women physicians are early adopters of on-line continuing medical education.

INTRODUCTION: On-line continuing medical education (CME) provides advantages to physicians and to medical educators. Although practicing physicians increasingly use on-line CME to meet their educational needs, the overall use of on-line CME remains limited. There are few data to describe the physicians who use this new educational medium; yet, they clearly are the innovators and early adopters who will facilitate the growth of this educational technology. It would be useful to instructional designers and CME developers to better understand the characteristics of this influential group. METHODS: We studied the actual use of several different on-line CME programs within three different groups of physicians. The on-line programs were developed as part of research studies funded by the National Institutes of Health, with no relationship to commercial interests. They were presented to physicians using mass mailouts (two physician groups) or personal contact and were accompanied by incentives to reduce resistance to the new technology. We compared the characteristics of physicians who chose to use these on-line programs with demographic data from larger populations representing the groups from which these users originated. RESULTS: We found that physicians who used these on-line CME programs were younger than average and, importantly, more likely to be female than expected. This finding was consistent across different types of physician populations and different types of CME programs. DISCUSSION: Based on data reflecting actual use of on-line CME, younger physicians appear to be adopting on-line CME more rapidly than others, and women physicians appear to be adopting on-line CME at a faster rate than their male counterparts. This latter finding conflicts with the impression provided by some survey-based studies that male physicians are more likely than female physicians to use on-line CME. The data suggest that the growth of on-line CME is most likely occurring in diffusion networks dominated by relatively new medical school graduates and, possibly, women physicians. These results provide valuable insight to those who seek to develop and market on-line CME and those who seek to reach women physicians with CME programs.

California↗
PubMed2002

Can Internet-based education improve physician confidence in dealing with domestic violence?

BACKGROUND AND OBJECTIVES: Domestic violence (DV) is a common, under-recognized source of visits to health care professionals. Even when recognized, physicians are reluctant to deal with DV, citing a lack of education and lack of confidence in addressing issues presented by DV patients. Only a small number of DV education programs have been shown to lead to improvements in professional knowledge and confidence, and these are intensive, multi-day courses. We sought to develop an on-line DV education program that could achieve improvements in physician confidence and attitudes in managing DV patients comparable to classroom-based courses. METHODS: We created an interactive, case-based DV education program targeted to physicians caring for DV patients. We tested the effectiveness of this program in changing attitudes and beliefs in a randomized, controlled trial of Kansas physicians who volunteered to participate in a study of on-line continuing medical education. We measured program effectiveness with an externally developed and validated pretest/posttest instrument. RESULTS: Sixty-five physicians completed the pretest/posttest, 28 of whom were assigned to receive the on-line DV program. We found a +17.8% mean change in confidence (self efficacy) for physicians who took the DV program versus a -.6% change for physicians who did not take the program. We also found improvements in other important areas associated with poor management of DV patients. These changes were similar or greater in magnitude to those reported by others who have used the same survey tool to evaluate an intensive, multi-hour classroom approach to DV education. User satisfaction with the on-line program was high. CONCLUSIONS: An interactive, case-based, on-line DV education program that teaches problem-solving skills improves physician confidence and beliefs in managing DV patients as effectively as an intensive classroom-based approach. Such programs may be of benefit to those seeking to improve their personal skills or their health care delivery system's response to DV.

Clinical Competence↗