There are 13 new articles in PLoS ONE today. As always, you should rate the articles, post notes and comments and send trackbacks when you blog about the papers. You can now also easily place articles on various social services (CiteULike, Connotea, Stumbleupon, Facebook and Digg) with just one click. Here are my own picks for the week - you go and look for your own favourites. The Big One today, I'll cover in a separate post a little later, but here I also want to point out a paper by my good friends Elsa Youngsteadt and Coby Schal, back from my NCSU days (Dr.Youngsteadt now works for Sigma Xi and attended ScienceOnline09):
Species-Specific Seed Dispersal in an Obligate Ant-Plant Mutualism by Elsa Youngsteadt, Jeniffer Alvarez Baca, Jason Osborne, Coby Schal:
Throughout lowland Amazonia, arboreal ants collect seeds of specific plants and cultivate them in nutrient-rich nests, forming diverse yet obligate and species-specific symbioses called Neotropical ant-gardens (AGs). The ants depend on their symbiotic plants for nest stability, and the plants depend on AGs for substrate and nutrients. Although the AGs are limited to specific participants, it is unknown at what stage specificity arises, and seed fate pathways in AG epiphytes are undocumented. Here we examine the specificity of the ant-seed interaction by comparing the ant community observed at general food baits to ants attracted to and removing seeds of the AG plant Peperomia macrostachya. We also compare seed removal rates under treatments that excluded vertebrates, arthropods, or both. In the bait study, only three of 70 ant species collected P. macrostachya seeds, and 84% of observed seed removal by ants was attributed to the AG ant Camponotus femoratus. In the exclusion experiment, arthropod exclusion significantly reduced seed removal rates, but vertebrate exclusion did not. We provide the most extensive empirical evidence of species specificity in the AG mutualism and begin to quantify factors that affect seed fate in order to understand conditions that favor its departure from the typical diffuse model of plant-animal mutualism.
We studied how well first-year medical students understand and apply the concept of substituted judgment, following a course on clinical ethics.
Students submitted essays on one of three ethically controversial scenarios presented in class. One scenario involved a patient who had lost decisional capacity. Through an iterative process of textual analysis, the essays were studied and coded for patterns in the ways students misunderstood or misapplied the principle of substituted judgment.
Students correctly articulated course principles regarding patient autonomy, substituted judgment, and non-imposition of physician values. However, students showed misunderstanding by giving doctors the responsibility of balancing the interests of the patient against the interests of the family, by stating doctors and surrogates should be guided primarily by a best-interest standard, and by suggesting that patient autonomy becomes the guiding principle only when patients can no longer express their wishes.
Students did not appear to internalize or correctly apply the substituted judgment standard, even though they could describe it accurately. This suggests the substituted judgment standard may run counter to students' moral intuitions, making it harder to apply in clinical practice.