Brood parasitism in the sand martin, Riparia riparia: evidence for two parasitic strategies in a colonial passerine

Sand martin parentage was studied at a large breeding colony in central Scotland. Multilocus DNA fingerprinting was used during the 3-year study to exclude some social parents as true parents, and thereby determine the frequency of monogamy, quasiparasitism (QP), intraspecific brood parasitism (ISBP) and extrapair fertilization (EPF) amongst 45 broods and 167 nestlings. Monogamous parentage characterized the majority of broods (60%), so most chicks were the offspring of their social parents (81%). QP (involving a male's extrapair mate laying in his nest) was found in 9% of broods and 2.4% of chicks and ISBP (or 'egg dumping') in 4% of broods and 1.8% of chicks. A substantial proportion of offspring arose from EPFs, affecting 36% of broods and 14% of chicks. On present evidence, the relatively high frequency of QP found in sand martins is unusual. We propose that its observed frequency is unlikely to be due to chance events and may represent a female-driven strategy. (c)1998 The Association for the Study of Animal Behaviour.     

Critical Communication Challenges For the New Century

This article, with minor modifications, was the author's presidential address to the 53rd annual conference of the International Communication Association. It presents several critical communication challenges for the early 21st century. First, it outlines the root causes of 3 classic divides that provide context for these challenges: theory versus practice, persuasion versus entertainment, and East versus West. The author suggests pathways toward syntheses of these divides, then discusses 3 communication challenges of particular interest to the author: legitimization and advancement of entertainment theory, redefinition and expansion of research on the digital divide, and development of a science of diplomatic communication.     

Spatial and temporal filtering of scintillation in remote sensing

The concept of spatial filtering as applied to remote sensing of the transverse flow velocity and refractive-index spectrum along a line-of-sight propagation path was first outlined in 1974. The technique was applied to optical propagation through the turbulent atmosphere. Random fluctuations in the field were produced by irregularities advected across the optical path by a mean flow. We extend and modify this earlier work to include source and receiver motion, temporal filtering, and dispersion of the refractive index structure. The technique described in this study can be applied to the remote probing of random atmospheric, ionospheric, and oceanic flows using either electromagnetic or acoustic sources. It can also be used for the remote sensing of rough surfaces such as the sea surface. The analysis indicates that this technique is a new, powerful tool with a unique capability for probing the spatial and temporal structure, and evolution of geophysical flows.     

Diet manipulation affects social behavior of catfish

Diet manipulation, an habituation test, and chemical analysis of urinary free amino acids were used to demonstrate that bullhead catfish (Ictalurus nebulosus) naturally detect the body odors of conspecifics and respond to them in a predictable fashion. These signals are used in dominance and territorial relationships and lead to increased aggression toward chemical strangers. The results support the general notion that nonspecific metabolites, as well as specific pheromones, are important in chemical mediation of social behavior.     

Distance preserving linear feature selection

A new method for linear feature selection is described which has as its underlying theme the preservation of actual distances between training data points in the lower dimensional space. Comparison with existing methodology places the method closer to the principle components or Karhunen- Loève approach than to methods based on an approach through statistical pattern recognition. A computer program implementing the technique is described. An example application to 12 dimensional LANDSAT data is given.     

Empirical evaluation of ridge regression.

Evaluated ridge regression by computer simulation over a variety of parameter conditions. Results show that ridge improved upon ordinary least squares only for a limited and predictable set of parametric conditions and did not provide a general antidote to the error variance accompanying multicollinearity. Ridge was effective for conditions of low R–2 (signal to noise ratio) and, for analyses based on the principle components of predictors, when principal components with small eigenvalues made only a small contribution to predicting the dependent variable. Routine use of ridge regression without prior knowledge of the predictor space is not recommended. Derivation of the orientation parameters is appended. (34 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The international vocabulary of basic and general terms in metrology

A new bilingual (French and English) international vocabulary of terms used in Metrology has been published by ISO on behalf of BIPM, IEC, ISO and OIML. This paper deals with the origins of the Vocabulary and with some of the problems which arose in the course of the work on its preparation: it also comments on some of the terms and definitions.