Use of Sensitivity Analysis to Assess Reliability of Metabolic and Physiological Models

Because ethical considerations often preclude directly determining the human health effects of treatments or interventions by experimentation, such effects are estimated by extrapolating reactions predicted from animal experiments. Under such conditions, it must be demonstrated that the reliability of the extrapolated predictions is not excessively affected by inherent data limitations and other components of model specification. This is especially true of high-level models composed of ad hoc algebraic equations whose parameters do not correspond to specific physical properties or processes. Models based on independent experimental data restricting the numerical space of parameters that do represent actual physical properties can be represented at a more detailed level. Sensitivities of the computed trajectories to parameter variations permit more detailed attribution of uncertainties in the predictions to these low-level properties. S-systems, in which parameters are estimated empirically, and physiological models, whose parameters can be estimated accurately from independent data, are used to illustrate the applicability of trajectory sensitivity analysis to lower-level models.     

Psychiatric hospitalization and process description: what will nursing add?

1. Inpatient treatment programs operating in the managed care environment must clearly articulate their treatment outcomes and the processes of care that are connected to these outcomes. 2. The work of inpatient psychiatric nurses can be organized and articulated through the therapeutic processes of the Four S Model: Safety, Structure, Support, and Symptom Management. 3. Nurses are vital contributors to the inpatient treatment process, but will be marginalized if they are unable to articulate how their interventions contribute to the positive treatment outcomes.     

Suicide ideation among US college students. Associations with other injury risk behaviors

Suicide, the endpoint of a continuum that begins with suicide ideation, is the third leading cause of death among the US college-aged population. The first and second leading causes of death among this age group, unintentional injury and homicide, may also be linked to suicide ideation. We used data from the National College Health Risk Behavior Survey to examine the association between suicide ideation and injury-related behaviors among 18- to 24-year-old college students. Students who reported suicide ideation were significantly more likely than students who did not report considering suicide to carry a weapon, engage in a physical fight, boat or swim after drinking alcohol, ride with a driver who had been drinking alcohol, drive after drinking alcohol, and rarely or never used seat belts. Given this clustering of injury-related risk behaviors, college prevention programs should aim to reduce risks for injuries comprehensively, rather than addressing each risk behavior separately.     

A new industrial order for physicians: a talk with Jeff C. Goldsmith, PhD. Interview by Richard L. Reece

Richard L. Reece, MD, interviewed Jeff C. Goldsmith, PhD, President of Health Futures, Inc. on October 12, 1999 to discuss how the Internet will affect health care delivery in the millennium. One of the most profound changes that he sees is how the relationship between physicians and patients will be altered. Empowered consumers are where the real revolution is happening--a trend sometimes overlooked by physicians. Goldsmith says, "The key thing physicians have missed is that the patient is in charge of the process.... The Internet has enabled patients to aggregate their collective experience across disease entities." But there is too much information. "It is almost universally acknowledged by patients and physicians that there is a terrible quality problem. Getting from information to knowledge is a huge commercial opportunity for somebody." He doesn't think that people have put enough emphasis on the collective learning part of this new technology.     

Business leadership as a spiritual discipline

What motivates organizational leaders in their search for spirituality? They seek to integrate their inner journey with their day-to-day professional roles. This article describes how a course in spirituality for executives has provided tools to analyze and clarify intentions, avoid the traps of excessive greed and power, and make decisions that are both compassionate and effective. André L. Delbecq, DBA, the Thomas J. and Kathleen L. McCarthy Professor at the Leavey School of Business at Santa Clara University in California, offers seminars in spirituality for organizational leadership through the MBA program and the Center for Executive Development. Delbecq is the first to admit his surprise at the number of executives who have repeatedly asked for courses in spirituality. He talks about how his seminars have helped CEOs and other top executives achieve greater effectiveness in leading organizations.     

Assessment of Airborne Exposure to Trihalomethanes from Tap Water in Residential Showers and Baths

This study evaluates airborne concentrations of common trihalomethane (THM) compounds in bathrooms during showering and bathing in homes supplied with chlorinated tap water. Three homes in an urban area were selected, each having three bedrooms, a full bath, and approximately 1,000 square feet of living area. THMs were concurrently measured in tap water and air in the shower/bath enclosure and the bathroom vanity area using Summa canisters. Chloroform (TCM), bromodichloromethane (BDCM), and chlorodibromomethane (CDBM) were quantified using U.S. Environmental Protection Agency (EPA) Method TO-14. Air samples were collected prior to, during, and after the water-use event for 16 shower and 7 bath events. Flow rate and temperature were measured, but not controlled. The increase in average airborne concentration (+/- standard error) during showers (expressed as microg/m3 in shower enclosure or bathroom air per microg/L in water) was 3.3+/-0.4 for TCM, 1.8+/-0.3 for BDCM, and 0.5+/-0.1 for CDBM (n = 12), and during baths was 1.2+/-0.4 for TCM, 0.59+/-0.21 for BDCM, and 0.15+/-0.05 for CDBM (n = 4). The relative contribution of each chemical to the airborne concentrations was consistent for all shower and bath events, with apparent release of TCM > BDCM > CDBM. The results are therefore consistent with their relative concentration in tap water and their vapor pressures. When the shower findings for TCM are normalized for water concentration, flow rate, shower volume, and duration, the average exposure concentrations in these urban residences are about 30% lower than those reported by other investigators using EPA analytical methods. This difference is likely attributable primarily to greater air exchange rates in residential shower/bath stalls compared to more "airtight" laboratory shower chambers. This appears to be the first field study to thoroughly evaluate THM exposures from residential showers and baths, and can be used to validate previously published models of tap water volatile chemical transfer to indoor air.     

Intergenerational and International Discounting

A discount rate for the consumption of future generations is typically composed of two parts. One is a "pure" time preference for immediate over postponed consumption, the other a declining marginal utility as consumption increases. The costs of greenhouse abatement, however, for at least the first 50 years, will be borne by the developed countries; the benefits will accrue to the presently undeveloped. Pure time preference always relates to one's own consumption; it has no relevance here. Consumption transfers over time will be from richer to poorer, from lower to higher marginal utility. It is a foreign aid program and it ought to have to compete with more direct foreign aid, which can benefit the very poor rather than their much-better-off descendants.     

IntroductionExposing Misinformation Concerning Child Sexual Abuse and Adult Survivors

This article introduces a special volume on misinformation about child sexual abuse. Despite extensive research findings on the long-term effects and consequences of child sexual abuse, misinformation on this topic is widespread. Several forces have worked to support and disseminate this erroneous information. Because it is difficult to comprehend the horror of sexual crimes against children, society's denial and disbelief have often unwittingly supported the agendas of those who want to discount or minimize the impact of these crimes. The media has also contributed to the aura of skepticism surrounding claims of sexual abuse and its mental health impact, and has reported favorably on controversial and unproven claims such as the “false memory syndrome.” In the hope of countering misinformation and thus raising the level of discourse to the engagement of real scientific issues, a number of well known and respected researchers and clinicians examine various facets of the problem.