There is evidence that asexual reproduction has a long-term disadvantage when compared to sexual reproduction. This disadvantage is usually assumed to arise from the more efficient incorporation of advantageous mutations by sexual populations. We consider here the effect on asexual and sexual populations of changes in the fitness of harmful mutations. It is shown that the re-establishment of equilibrium following environmental change is generally faster in sexual populations, and that the mutational load experienced by the sexual population can be significantly (...) less during this period than that experienced by an asexual one. Changes in the fitness of harmful mutations may therefore impose a greater long-term disadvantage on asexual populations than those which are sexual. (shrink)

OBJECTIVE: To examine the long-term effects of an innovative curriculum on medical house officers' (HOs') knowledge, confidence, and attitudes regarding medical ethics. DESIGN: Long term cohort study. The two-year curriculum, implemented by a single physician ethicist with assistance from other faculty, was fully integrated into the programme. It consisted of monthly sessions: ethics morning report alternating with didactic conferences. The content included topics such as ethics vocabulary and principles, withdrawing life support, informed consent, and justice. Identical content was offered simultaneously (...) at the largest affiliated community hospital. SETTING: A multi-hospital university training programme from July, 1992 to June, 1994. PARTICIPANTS: Thirty-nine HOs responded in 92. Thirty HOs from the same cohort responded in 94 (response rates = 83% v 71%; P = 0.19). RESULTS: The curriculum was well received, with 96% of HOs finding the sessions stimulating. Previously validated scales of knowledge and confidence were administered at baseline and at follow-up. The average knowledge score improved 14% (P < 0.001). Confidence also improved, rising from 3.3 to 3.8 on a 5-point Likert scale (P < 0.001). These findings were independent of age, gender, religion, and prior education. The only attitudinal change was an increase in the proportion of residents who thought that ethics should be a required part of residency training (57% v 80%, P = 0.05). CONCLUSION: This curriculum appears practical, popular, and effective. It should be readily transferable to other institutions. (shrink)

A recently formulated concept of stochastic localizability is shown to be consistent with a concept of stochastic microcausality, which avoids the conclusions of Hegerfeldt's no-go theorem as to the inconsistency of sharp localizability of quantum particles and Einstein causality. The proposed localizability on quantum space-time is shown to lead to strict asymptotic causality. For finite time evolutions, upper bounds on propagation to the exterior of stochastic light cones are derived which show that the resulting probabilities are too small to be (...) actually observable in a realistic context. (shrink)

OBJECTIVES: To study the accuracy of reviewing ward notes (chart review) as a measure of the quality of care rendered to patients with "Do Not Resuscitate" (DNR) orders. DESIGN: We reviewed the charts of 19 consecutive, competent inpatients with DNR orders for evidence that the staff addressed a broad range of patient care needs called Concurrent Care Concerns (CCCs), such as withholding treatments other than resuscitation itself, and attention to patient comfort needs. We then interviewed the patient, consultant physician, house (...) officer, and primary nurse and compared the ward notes with the understandings of these staff members. SETTING: The medical service of an urban university medical centre. RESULTS: The average number of documented CCCs addressed per DNR order was 1.1. The ward notes generally agreed with the perceptions of patients, house officers, and nurses (% agreement with notes = 79%, 77%, and 82%; kappa = 0.43, 0.40, 0.50). Consultant physicians' understandings were poorly reflected in the ward notes (% agreement = 59%; kappa = 0.18). They overestimated attention to CCCs compared with the notes (P < 0.0001) and with other observers (P < 0.0001). CONCLUSION: Chart review for attention to CCCs accurately reflects the understandings of patients, house officers, and nurses, but consultant physicians report more attention to CCCs than is recorded in the ward notes or understood by other observers. Better communication regarding end-of-life care plans should be encouraged. (shrink)

This study represents an improvement in the ethics scales inventory published in a 1988 Journal of Business Ethics article. The article presents the distillation and validation process whereby the original 33 item inventory was reduced to eight items. These eight items comprise the following ethical dimensions: a moral equity dimension, a relativism dimension, and a contractualism dimension. The multidimensional ethics scale demonstrates significant predictive ability.

Although nature of science and nature of scientific inquiry are related to each other, they are differentiated as NOS is being more related to the product of scientific inquiry which is scientific knowledge whereas NOSI is more related to the process of SI. Lederman et al. determined eight NOSI aspects for K-16 context. In this study, a science camp was conducted to teach scientific inquiry and NOSI to 24 6th and 7th graders. The core of the program was guided inquiry (...) in nature. The children working in small groups under guidance of science advisors conducted four guided-inquiries in the nature in morning sessions on nearby plants, animals, water, and soil. NOSI aspects were made explicit during and at the end of each inquiry session. Views about scientific inquiry questionnaire was applied as pre- and post-test. The results of the study showed that children developed in all eight NOSI aspects, but higher developments were observed in “scientific investigations all begin with a question” and “there is no single scientific method,” and “explanations are developed from data and what is already known” aspects. It was concluded that the science camp program was effective in teaching NOSI. (shrink)

We begin with the idea that lines of reasoning are continuous mental processes and develop a notion of continuity in proof. This requires abstracting the notion of a proof as a set of sentences ordered by provability. We can then distinguish between discrete steps of a proof and possibly continuous stages, defining indexing functions to pick these out. Proof stages can be associated with the application of continuously variable rules, connecting continuity in lines of reasoning with continuously variable reasons. Some (...) examples of continuous proofs are provided. We conclude by presenting some fundamental facts about continuous proofs, analogous to continuous structural rules and composition. We take this to be a development on its own, as well as lending support to non-finitistic constructionism. (shrink)

The focus of this study was to analyze the content, distribution, and comparative genome relationships of 996 chromosome bin-mapped expressed sequence tags accounting for 2266 restriction fragments on the homoeologous group 3 chromosomes of hexaploid wheat. Of these loci, 634, 884, and 748 were mapped on chromosomes 3A, 3B, and 3D, respectively. The individual chromosome bin maps revealed bins with a high density of mapped ESTs in the distal region and bins of low density in the proximal region of the (...) chromosome arms, with the exception of 3DS and 3DL. These distributions were more localized on the higher-resolution group 3 consensus map with intermediate regions of high-mapped-EST density on both chromosome arms. Gene ontology classification of mapped ESTs was not significantly different for homoeologous group 3 chromosomes compared to the other groups. A combined analysis of the individual bin maps using 537 of the mapped ESTs revealed rearrangements between the group 3 chromosomes. Approximately 232 of the consensus mapped ESTs matched sequences on rice chromosome 1 and revealed large- and small-scale differences in gene order. Of the group 3 mapped EST unigenes ∼21 and 32% matched the Arabidopsis coding regions and proteins, respectively, but no chromosome-level gene order conservation was detected. (shrink)

The objectives of this study were to develop a high-density chromosome bin map of homoeologous group 7 in hexaploid wheat, to identify gene distribution in these chromosomes, and to perform comparative studies of wheat with rice and barley. We mapped 2148 loci from 919 EST clones onto group 7 chromosomes of wheat. In the majority of cases the numbers of loci were significantly lower in the centromeric regions and tended to increase in the distal regions. The level of duplicated loci (...) in this group was 24% with most of these loci being localized toward the distal regions. One hundred nineteen EST probes that hybridized to three fragments and mapped to the three group 7 chromosomes were designated landmark probes and were used to construct a consensus homoeologous group 7 map. An additional 49 probes that mapped to 7AS, 7DS, and the ancestral translocated segment involving 7BS also were designated landmarks. Landmark probe orders and comparative maps of wheat, rice, and barley were produced on the basis of corresponding rice BAC/PAC and genetic markers that mapped on chromosomes 6 and 8 of rice. Identification of landmark ESTs and development of consensus maps may provide a framework of conserved coding regions predating the evolution of wheat genomes. (shrink)

Recordings of neuronal activity in the monkey superior colliculus (SC) suggest that the two apparently independent effects of a visual distractor on both temporal (latency) and spatial (metrics) saccade parameters may be the result of lateral interactions between subpopulations of saccade-related neurons located at different sites on the motor map of the superior colliculus. One subpopulation is activated during the planing and initiation of a saccade; the other is activated by the appearance of a distractor. The inhibitory or facilitative nature (...) of this interaction depends on the distance between the distractor and the target and is consistent with the complex pattern of intrinsic and commissural collicular connections. (shrink)