PRINCIPLISM AND THE ETHICAL APPRAISAL OF CLINICAL TRIALS

For nearly two decades, the process of reviewing the ethical merit of research involving human subjects has been based on the application of principles initially described in the U.S. National Commission's Belmont Report, and later articulated more fully by Beauchamp and Childress in their Principles of Biomedical Ethics. Recently, the use of ethical principles for deliberating about moral problems in medicine and research, referred to in the pejorative sense as “principlism”, has come under scrutiny. In this paper we argue that these principles can provide a foundation for the source of ethical appraisal of human research, but are not themselves wholly adequate for this purpose. Therefore, we further propose that (1) principles should be understood as heuristics that can be “specified” as described by DeGrazia (1992), and (2) that the principle-based approach should be supplemented by formally incorporating “sensitivity to context” into the evaluation of clinical trials     

国际植物学墨尔本大会上命名法规的变化

2011年7月在第18届国际植物学大会命名法分会上通过了命名法规的一系列重大改动,并在全体大会上得到了接受批准。文中就命名法规的变化进行了简单概述,同时也讨论了这些变化的意义,特别是对菌物研究的意义,以期引起广大研究人员的关注。     

Mid-season shifts in the habitat associations of Yellow Wagtails Motacilla flava breeding in arable farmland

Declines in habitat quality through the breeding season within a bird's home-range can limit overall productivity. In environments where multiple breeding opportunities arise during the course of a season, these effects can be buffered by a shift to different breeding sites or habitats. We studied the distribution and habitat associations of a crop-nesting farmland bird, the Yellow Wagtail Motacilla flava , across an arable-dominated farming region in eastern England using both field-scale territory mapping and large-scale transect surveys. Surveys were repeated at monthly intervals to measure changes in both distribution and habitat use during the course of the season. The distribution of breeding birds changed markedly at both regional and field-scales, coinciding with a shift in crop preference. Initially, most territorial birds were recorded in autumn-sown cereal fields, but this crop was subsequently abandoned in favour of potato crops, which were more patchily distributed. Other habitat features influencing Yellow Wagtail distribution included local crop diversity, hedgerow presence and soil type, with organic soils supporting higher abundance than alluvial clays or silts. The mid-season switch in habitat associations might allow individuals to maximize the number of breeding attempts made in a single year by using multiple habitats sequentially. The use of multiple habitats could influence population regulation by buffering the effects of local within-season declines in habitat suitability. Seasonal habitat switching may be more prevalent than is currently recognized in seasonal environments.     

Molecular dynamics study of the KcsA potassium channel

The structural, dynamical, and thermodynamic properties of a model potassium channel are studied using molecular dynamics simulations. We use the recently unveiled protein structure for the KcsA potassium channel from Streptomyces lividans. Total and free energy profiles of potassium and sodium ions reveal a considerable preference for the larger potassium ions. The selectivity of the channel arises from its ability to completely solvate the potassium ions, but not the smaller sodium ions. Self-diffusion of water within the narrow selectivity filter is found to be reduced by an order of magnitude from bulk levels, whereas the wider hydrophobic section of the pore maintains near-bulk self-diffusion. Simulations examining multiple ion configurations suggest a two-ion channel. Ion diffusion is found to be reduced to approximately (1)/(3) of bulk diffusion within the selectivity filter. The reduced ion mobility does not hinder the passage of ions, as permeation appears to be driven by Coulomb repulsion within this multiple ion channel.     

Silver Nitrate Increases Embryo Production in Anther Culture of Brussels Sprouts

Embryo production from anther culture of three poorly respondingBrussels sprouts genotypes was increased in 10 out of 13 experimentsby the inclusion of the ethylene antagonist silver nitrate (AgNO₃)in the medium. When applied to a normally responsive genotype,AgNO₃ increased embryo yield in only one of three experiments.At only one concentration in one of the 16 experiments, didAgNO₃ inhibit embryogenesis. Silver nitrate, anther culture, Brassica oleracea, ethylene