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Biomedical subjects

William A Nelson

Publications and source records attributed to William A Nelson.

10 recordsLinked to original sources
PubMed2006

Characteristics of rural and urban cadaveric organ transplant donors and recipients.

CONTEXT: Health disparities have been found when comparing rural and urban populations. PURPOSE: To compare characteristics of rural and urban cadaveric transplant donors and recipients. METHODS: We used deidentified individual-level data on 55,929 cadaveric transplant donor-recipient exchanges between 2000 and 2003 and examined the relative rates of donating and receiving cadaveric transplants for rural compared to urban residents, as defined by ZIP Codes. FINDINGS: When compared to their urban counterparts, rural organ donors were more likely to have died from head trauma, drowning, motor vehicle accidents, or suicide and less likely to have died from cerebrovascular events, cardiac events, or homicide (P < .001 for all). Rural transplant recipients had lower levels of educational attainment and were less likely to have had the transplant financed by private insurance (P < .001 for all). While we found no statistical difference in days wait to organ transplantation, rural residents were more likely to donate than to receive cadaveric organs (P < .001). CONCLUSIONS: The differences in organ donation that we found warrant further exploration.

Adult↗
PubMed2005

Stage-structured cycles promote genetic diversity in a predator-prey system of Daphnia and algae.

Competition theory predicts that population fluctuations can promote genetic diversity when combined with density-dependent selection. However, this stabilizing mechanism has rarely been tested, and was recently rejected as an explanation for maintaining diversity in natural populations of the freshwater herbivore Daphnia pulex. The primary limitation of competition theory is its failure to account for the alternative types of population cycles that are caused by size- or stage-dependent population vital rates--even though such structure both explains the fluctuating dynamics of many species and may alter the outcome of competition. Here we provide the first experimental test of whether alternative types of cycles affect natural selection in predator-prey systems. Using competing Daphnia genotypes, we show that internally generated, stage-structured cycles substantially reduce the magnitude of selection (thereby contributing to the maintenance of genetic diversity), whereas externally forced cycles show rapid competitive exclusion. The change in selection is ecologically significant, spanning the observed range in natural populations. We argue that structured cycles reduce selection through a combination of stalled juvenile development and stage-specific mortality. This potentially general fitness-equalizing mechanism may reduce the need for strong stabilizing mechanisms to explain the maintenance of genetic diversity in natural systems.

Animals↗
PubMedDate not supplied

Ten myths about decision-making capacity.

As a matter of practical reality, what role patients will play in decisions about their health care is determined by whether their clinicians judge them to have decision-making capacity. Because so much hinges on assessments of capacity, clinicians who work with patients have an ethical obligation to understand this concept. This article, based on a report prepared by the National Ethics Committee (NEC) of the Veterans Health Administration (VHA), seeks to provide clinicians with practical information about decision-making capacity and how it is assessed. A study of clinicians and ethics committee chairs carried out under the auspices of the NEC identified the following 10 common myths clinicians hold about decision-making capacity: (1) decision-making capacity and competency are the same; (2) lack of decision-making capacity can be presumed when patients go against medical advice; (3) there is no need to assess decision-making capacity unless patients go against medical advice; (4) decision-making capacity is an "all or nothing" phenomenon; (5) cognitive impairment equals lack of decision-making capacity; (6) lack of decision-making capacity is a permanent condition; (7) patients who have not been given relevant and consistent information about their treatment lack decision-making capacity; (8) all patients with certain psychiatric disorders lack decision-making capacity; (9) patients who are involuntarily committed lack decision-making capacity; and (10) only mental health experts can assess decision-making capacity. By describing and debunking these common misconceptions, this article attempts to prevent potential errors in the clinical assessment of decision-making capacity, thereby supporting patients' right to make choices about their own health care.

Cognition Disorders↗
PubMedDate not supplied

Ten myths about decision-making capacity.

As a matter of practical reality, what role patients will play in decisions about their health care is determined by whether their clinicians judge them to have decision-making capacity. Because so much hinges on assessments of capacity, clinicians who work with patients have an ethical obligation to understand this concept. This article, based on a report prepared by the National Ethics Committee (NEC) of the Veterans Health Administration (VHA), seeks to provide clinicians with practical information about decision-making capacity and how it is assessed. A study of clinicians and ethics committee chairs carried out under the auspices of the NEC identified the following 10 common myths clinicians hold about decision-making capacity: (1) decision-making capacity and competency are the same; (2) lack of decision-making capacity can be presumed when patients go against medical advice; (3) there is no need to assess decision-making capacity unless patients go against medical advice; (4) decision-making capacity is an "all or nothing" phenomenon; (5) cognitive impairment equals lack of decision-making capacity; (6) lack of decision-making capacity is a permanent condition; (7) patients who have not been given relevant and consistent information about their treatment lack decision-making capacity; (8) all patients with certain psychiatric disorders lack decision-making capacity; (9) patients who are involuntarily committed lack decision-making capacity; and (10) only mental health experts can assess decision-making capacity. By describing and debunking these common misconceptions, this article attempts to prevent potential errors in the clinical assessment of decision-making capacity, thereby supporting patients' right to make choices about their own health care.

Attitude of Health Personnel↗
PubMedDate not supplied

An organizational ethics decision-making process.

The management team of Memorial Medical Center must make a decision regarding the continuation of one of its outpatient clinics. To provide better community service, MMC developed three outpatient clinics throughout a large metropolitan area. Over the past several years, one of the clinics has consistently been a financial loser. The losses have grown even as the costs of maintaining the clinic have increased. A primary reason for the negative financial performance is the high amount of nonreimbursed healthcare services-the clinic provides needed healthcare to a low-income part of the metropolitan area. Several members of the executive management team believe MMC has no alternative other than closing the clinic. One member of the management team, however, believes that the situation raises ethical concerns, and that executive seeks an ethics-grounded response to the problem.

Decision Making, Organizational↗