Guilt by Association: The Culture of Accusation and the American Anthropological Association's Investigation of Darkness in El Dorado

The American Anthropological Association's investigation of the charges in Darkness in El Dorado (Tierney 2000) found that the late James Neel and Napoleon Chagnon harmed the Yanomami in the course of their research in Venezuela and Brazil, and that Chagnon had violated the ethics code of the association. The association's inquiry contravened its own policy prohibiting ethics adjudications and was structured not by the standards of an objective investigation but by aspects of contemporary anthropology. Moralized approaches to information and postmodern rejection of objectivity mark the language and methods of the inquiry. The investigating task force did not observe reasonable standards of evidence, the targets of the investigation were not represented, and task force members were compromised by conflicts of interest. The investigation and its collateral activities reflect a culture of accusation and an anthropology uncertain of its ethical or scientific stature.     

PATHOPHYSIOLOGY OF DEPRESSION: DO WE HAVE ANY SOLID EVIDENCE OF INTEREST TO CLINICIANS?

Due to the clinical and etiological heterogeneity of major depressive disorder, it has been difficult to elucidate its pathophysiology. Current neurobiological theories with the most valid empirical foundation and the highest clinical relevance are reviewed with respect to their strengths and weaknesses. The selected theories are based on studies investigating psychosocial stress and stress hormones, neurotransmitters such as serotonin, norepinephrine, dopamine, glutamate and gamma-aminobutyric acid (GABA), neurocircuitry, neurotrophic factors, and circadian rhythms. Because all theories of depression apply to only some types of depressed patients but not others, and because depressive pathophysiology may vary considerably across the course of illness, the current extant knowledge argues against a unified hypothesis of depression. As a consequence, antidepressant treatments, including psychological and biological approaches, should be tailored for individual patients and disease states. Individual depression hypotheses based on neurobiological knowledge are discussed in terms of their interest to both clinicians in daily practice and clinical researchers developing novel therapies.     

The sedimentation of amyloplasts in living statocytes of the dandelion flower stalk

Abstract The sedimentation of amyloplasts in inverted statocytes of the flower stalk of dandelion (Taraxacum officinale Weber) was followed using light microscopy. Much variety in sedimentation pattern was evident with complete sedimentation occurring in as little as 3–4 min to as much as a few h and individual amyloplasts showing barely perceptible sedimentation or sedimenting at speeds of up to 40 μm min^?1. It was also apparent that amyloplasts were subjected to considerable movement after they had sedimented. Large vacuoles and cytoplasmic streaming in statocytes were confirmed and are considered to greatly influence amy-loplast sedimentation pattern. The implications of these observations for the starch-statolith hypothesis of geotropism are discussed.     

Potential for passive internal dispersal: eggs of an aquatic leaf beetle survive passage through the digestive system of mallards

相似文献   

Analysis of particle motion in sieve tubes of Heracleum

Abstract. We have cine-filmed the random motion of microscopic particles, mostly starch grains from ruptured plastids, in sieve tubes of Heracleum mantegazzianum L. and H. sphohdylium Somm. and Lev. Our frame-by-frame analysis of the positions of the particles shows that they move much less than calculated when generally accepted estimates for the viscosity of sieve-lube sap are inserted in the Stokes-Einstein and other equations for Brownian motion. Our analysis of a film, of similar particles, made by previous workers leads us to disagree with their conclusion that particle movement in sieve tubes was greater than should be expected for ordinary Brownian motion. Particles in their film and in ours moved less than expected even when we allow for the possibility that the particles are restricted by cell walls and by each other. We suggest that the particles move less than expected because the viscosity of sieve-lube sap may be higher than has been assumed by physiologists.     

Oxygen consumption of the aquatic leaf beetles Macroplea mutica and Macroplea appendiculata is low and not influenced by salinity

Leaf beetles of the genus Macroplea live permanently under water. Species‐specific preferences for either freshwater or brackish water are available in the literature. To detect potential physiological differences, the oxygen consumption of Macroplea mutica and Macroplea appendiculata from habitats with differing salinities is measured at two different salinities (0 and 10). The specific oxygen consumption does not depend on oxygen saturation of the water (values in the approximate range of 25–100% occur during the experiments). There is no difference between species or sampling locations. Similarly, the salinity during the measurements does not affect the oxygen consumption of the beetles, either when compared as salinity per se (0 versus 10), or when classified as home salinity or atypical salinity. Comparisons with other chrysomelid beetles and aquatic insects (using available published data) reveal that the two Macroplea species have relatively low metabolic rates. This finding is discussed in the light of activity patterns and morphology, especially the reduction of flight muscles, which comprise a highly metabolically active tissue.     

Differentiation of metallicolous and non‐metallicolous Salix caprea populations based on phenotypic characteristics and nuclear microsatellite (SSR) markers

The Salicaceae family comprises a large number of high‐biomass species with remarkable genetic variability and adaptation to ecological niches. Salix caprea survives in heavy metal contaminated areas, translocates and accumulates Zn/Cd in leaves. To reveal potential selective effects of long‐term heavy metal contaminations on the genetic structure and Zn/Cd accumulation capacity, 170 S. caprea isolates of four metal‐contaminated and three non‐contaminated middle European sites were analysed with microsatellite markers using Wright's F statistics. The differentiation of populations North of the Alps are more pronounced compared to the Southern ones. By grouping the isolates based on their contamination status, a weak but significant differentiation was calculated between Northern metallicolous and non‐metallicolous populations. To quantify if the contamination and genetic status of the populations correlate with Zn/Cd tolerance and the accumulation capacity, the S. caprea isolates were exposed to elevated Cd/Zn concentrations in perlite‐based cultures. Consistent with the genetic data nested anova analyses for the physiological traits find a significant difference in the Cd accumulation capacity between the Northern and Southern populations. Our data suggest that natural populations are a profitable source to uncover genetic mechanisms of heavy metal accumulation and biomass production, traits that are essential for improving phytoextraction strategies.