Food-web structure in low- and high-dimensional trophic niche spaces

A question central to modelling and, ultimately, managing food webs concerns the dimensionality of trophic niche space, that is, the number of independent traits relevant for determining consumer-resource links. Food-web topologies can often be interpreted by assuming resource traits to be specified by points along a line and each consumer's diet to be given by resources contained in an interval on this line. This phenomenon, called intervality, has been known for 30 years and is widely acknowledged to indicate that trophic niche space is close to one-dimensional. We show that the degrees of intervality observed in nature can be reproduced in arbitrary-dimensional trophic niche spaces, provided that the processes of evolutionary diversification and adaptation are taken into account. Contrary to expectations, intervality is least pronounced at intermediate dimensions and steadily improves towards lower- and higher-dimensional trophic niche spaces.

Beyond the Orange and the Green. The Diversification of the Qualitative Social Research Landscape in Northern Ireland.

The Northern Ireland conflict has been described as one of the most over-researched conflicts in the world. However, this is a relatively recent development. For many years, when the conflict was most intense, social scientists in Northern Ireland were silent and not vocal. The sectarian violence that dominated the life in Northern Ireland as well as the fact that the country was a fundamentally unjust society contributed to this silence. However, since the peace process began in the mid 1990s, a growing number of qualitative studies have been published, utilising one-to-one interviews and focus group discussions, in order to "make people's voices heard" and deal with the consequences of the so-called "Troubles". This paper looks into the emergence of a qualitative social research landscape in Northern Ireland beyond the conflict and explores issues so far neglected. It is argued that a number of factors have contributed to this, among them the availability of research funding to voluntary and community sector organisations that use their data to influence policy-making and equality legislation in a country which is still deeply divided along socio-religious lines.

An operant determination of the behavioural mechanism of benzodiazepine enhancement of food intake

Rationale A recent review paper by Cooper (Appetite 44:133–150, 2005) has pointed out that a role for benzodiazepines as appetite stimulants has been largely overlooked. Cooper’s review cited several studies that suggested the putative mechanism of enhancement of food intake after benzodiazepine administration might involve increasing the perceived pleasantness of food (palatability). Objectives The present study examined the behavioral mechanism of increased food intake after benzodiazepine administration. Materials and methods The cyclic-ratio operant schedule has been proposed as a useful behavioral assay for differentiating palatability from regulatory effects on food intake (Ettinger and Staddon, Physiol Behav 29:455–458, 1982 and Behav Neurosci 97:639–653, 1983). The current study employed the cyclic-ratio schedule to determine whether the effects on food intake of chlordiazepoxide (CDP) (5.0 mg/kg), sodium pentobarbital (5.0 mg/kg), and picrotoxin (1.0 mg/kg) were mediated through palatability or regulatory processes. Results The results of this study show that both the benzodiazepine CDP and the barbiturate sodium pentobarbital increased food intake in a manner similar to increasing the palatability of the ingestant, and picrotoxin decreased food intake in a manner similar to decreasing the palatability of the ingestant. Conclusions These results suggest that the food intake enhancement properties of benzodiazepines are mediated through a mechanism affecting perceived palatability.

Application of guar gum as a flocculant aid in food processing and potable water treatment

The paper deals with use of a food grade coagulant (guar gum) as a replacement for synthetic coagulants for potable water treatment.