Variation in monthly sizes of home-ranges of Hooded Vultures Necrosyrtes monachus in western,eastern and southern Africa

Tracking studies are often used to inform conservation plans and actions. However, species have frequently only been tracked in one or a few localities, whereas space use can be remarkably flexible, especially in long-lived species with advanced learning abilities. We assessed variability in space use in the Critically Endangered Hooded Vulture Necrosyrtes monachus by pooling movement data from three populations across the species’ sub-Saharan range (in South Africa, Botswana, Ethiopia, Kenya, The Gambia and Mozambique). We estimated minimum convex polygons and kernel density estimators (KDEs) and compared monthly home-range sizes between breeding and non-breeding seasons, age-classes and subspecies, accounting for uneven sampling within groups. Mean (± sd) monthly home-range sizes (95% KDEs) for adult Hooded Vultures from southern (12 453 ± 21 188 km², n = 82) and eastern Africa (3735 ± 3652 km², n = 24) were 103 and 31 times larger than those of conspecifics from western Africa (121 ± 98 km², n = 48). This may relate partly to subspecific differences, and individuals with small home-ranges in western Africa and Ethiopia were trapped in urban environments. Regional variation in space use by Hooded Vultures may be linked to flexibility in feeding behaviour (degree of commensalism) which may arise in response to resource availability and persecution in different areas. Age-class also affected monthly home-range sizes, with immature birds generally having larger monthly home-range size estimates than adults. Our results highlight the flexibility of Hooded Vultures in terms of their home-range sizes and suggest that home-range sizes differ between populations and individuals, depending on the extent of human commensalism. Our results also reaffirm the importance of international co-operation in conservation efforts aimed at protecting this wide-ranging, non-migratory species.     

Effects of light,dissolved nutrients and prey on ingestion and growth of a newly identified mixotrophic alga,Chrysolepidomonas dendrolepidota (Chrysophyceae)

Hydrobiologia - Chrysolepidomonas dendrolepidota was described recently and little is known of its distribution, physiology or ecology. Although many photosynthetic chrysophytes have been...     

A comparison of methods for callus culture and plant regeneration of RD25 rice (Oryza sativa L.) in two laboratories

While methodology is transferable from one laboratory to another, an exact transfer does not usually occur and even a nearly exact transfer of methods does not always result in repeatable data. Researchers should not expect that an effort to duplicate a published procedure will necessarily lead to identical results.In attempting to transfer rice tissue culture methods between laboratories in Fort Collins, Colorado, USA and Bangkok, Thailand, we discovered that a combination of the methods of each laboratory produced the best results in term of callus productions and plant regeneration. In the experiments reported here, the type of culture vessel used and the geographical location were also important variables.Supported by the USAID/Cooperative Agreement No DAN-4137-A-00-4053-00.     

Spring loading a pre-cleavage intermediate for hairpin telomere formation

The Borrelia telomere resolvase, ResT, forms the unusual hairpin telomeres of the linear Borrelia replicons in a process referred to as telomere resolution. Telomere resolution is a DNA cleavage and rejoining reaction that proceeds from a replicated telomere intermediate in a reaction with mechanistic similarities to that catalyzed by type IB topoisomerases. Previous reports have implicated the hairpin-binding module, at the end of the N-terminal domain of ResT, in distorting the DNA between the scissile phosphates so as to promote DNA cleavage and hairpin formation by the catalytic domain. We report that unwinding the DNA between the scissile phosphates, prior to DNA cleavage, is a key cold-sensitive step in telomere resolution. Through the analysis of ResT mutants, rescued by substrate modifications that mimic DNA unwinding between the cleavage sites, we show that formation and/or stabilization of an underwound pre-cleavage intermediate depends upon cooperation of the hairpin-binding module and catalytic domain. The phenotype of the mutants argues that the pre-cleavage intermediate promotes strand ejection to favor the forward reaction and that subsequent hairpin capture is a reversible reaction step. These reaction features are proposed to promote hairpin formation over strand resealing while allowing reversal back to substrate of aborted reactions.     

Seeing storms behind the clouds: Biases in the attribution of anger

Anger-prone individuals are volatile and frequently dangerous. Accordingly, inferring the presence of this personality trait in others was important in ancestral human populations. This inference, made under uncertainty, can result in two types of errors: underestimation or overestimation of trait anger. Averaged over evolutionary time, underestimation will have been the more costly error, as the fitness decrements resulting from physical harm or death due to insufficient vigilance are greater than those resulting from lost social opportunities due to excessive caution. We therefore hypothesized that selection has favored an upwards bias in the estimation of others' trait anger relative to estimations of other traits not characterized by such an error asymmetry. Moreover, we hypothesized that additional attributes that i) make the actor more dangerous, or ii) make the observer more vulnerable increase the error asymmetry with regard to inferring anger-proneness, and should therefore correspondingly increase this overestimation bias. In Study 1 (N = 161), a fictitious individual portrayed in a vignette was judged to have higher trait anger than trait disgust, and trait anger ratings were more responsive than trait disgust ratings to behavioral cues of emotionality. In Study 2 (N = 335), participants viewed images of angry or fearful faces. The interaction of factors indicating target's formidability (male sex), target's intent to harm (direct gaze), and perceiver's vulnerability (female sex or high belief in a dangerous world) increased ratings of the target's trait anger but not trait fear.