No abstract

JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact support@jstor.org.Abstract. Microhabitat partitioning based on microhabitat-specific predation rates has been well documented as a mechanism of coexistence in desert rodents. In the Namib Desert, two species of rodent, a nocturnal dune hairy-footed gerbil, Gerbillurus tytonis, and a diurnal striped mouse, Rhabdomys pumilio, co-occur in a vegetated island in the dune sea. The species show a marked preference for the same microhabitat, although gerbils also inhabit a second microhabitat where predation risk is greater. We provide direct experimental evidence for the role of predation risk and both interand intraspecific competition in affecting foraging behavior and habitat selection of gerbils. Using two techniques (tracking and seed trays), we were able to show that gerbils decrease foraging activity in vegetated areas during periods of increased illumination (full-moon periods). Removal of a potential competitor, the striped mouse, as well as removal of conspecifics, resulted in a significant increase in gerbil foraging activity. We propose that high susceptibility to predation results in a shared preference for the safest habitat and leads to competition for limited resources.

Targeted muscle reinnervation (TMR) amplifies the electrical activity of nerves at the stump of amputees by redirecting them in remnant muscles above the amputation. The electrical activity of the reinnervated muscles can be used to extract natural control signals. Nonetheless, current control systems, mainly based on noninvasive muscle recordings, fail to provide accurate and reliable control over time. This is one of the major reasons for prosthetic abandonment. This prospective interventional study includes three unilateral above-elbow amputees and reports the long-term (2.5 years) implant of wireless myoelectric sensors in the reinnervation sites after TMR and their use for control of robotic arms in daily life. It therefore demonstrates the clinical viability of chronically implanted myoelectric interfaces that amplify nerve activity through TMR. The patients showed substantial functional improvements using the implanted system compared with control based on surface electrodes. The combination of TMR and chronically implanted sensors may drastically improve robotic limb replacement in above-elbow amputees.

Psittacine beak and feather disease (PBFD), caused by Beak and feather disease virus (BFDV), is the most significant infectious disease in psittacines. PBFD is thought to have originated in Australia but is now found worldwide; in Africa, it threatens the survival of the indigenous endangered Cape parrot and the vulnerable black-cheeked lovebird. We investigated the genetic diversity of putative BFDVs from southern Africa. Feathers and heparinized blood samples were collected from 27 birds representing 9 psittacine species, all showing clinical signs of PBFD. DNA extracted from these samples was used for PCR amplification of the putative BFDV coat protein (CP) gene. The nucleotide sequences of the CP genes of 19 unique BFDV isolates were determined and compared with the 24 previously described sequences of BFDV isolates from Australasia and America. Phylogenetic analysis revealed eight BFDV lineages, with the southern African isolates representing at least three distinctly unique genotypes; 10 complete genome sequences were determined, representing at least one of every distinct lineage. The nucleotide diversity of the southern African isolates was calculated to be 6.4% and is comparable to that found in Australia and New Zealand. BFDVs in southern Africa have, however, diverged substantially from viruses found in other parts of the world, as the average distance between the southern African isolates and BFDV isolates from Australia ranged from 8.3 to 10.8%. In addition to point mutations, recombination was found to contribute substantially to the level of genetic variation among BFDVs, with evidence of recombination in all but one of the genomes analyzed.

Supplementary File S1: Questionnaire sent to individuals and organisations involved with parrot research and conservation soliciting information on conservation status and opinions on threats, and priority actions for research and conservation within their area of expertise. Categories for scope, severity and impact of different threats adapted from the IUCN-CMP Unified Classification of Direct Threats version 3.1 THE CONSERVATION STATUS OF AFRICAN PARROTSThis survey is being conducted as part of an initiative of the Parrot Researchers Group (PRG) / Research Coordination Committee on Parrots (RCCP) of the International Ornithologists' Union (IOU), to review the conservation status of African Parrots and identify conservation and research priorities. Your assistance is greatly appreciated and your contribution will be acknowledged in all reports.