How does global change affect the strength of trophic interactions?

Recent research has generally shown that a small change in the number of species in a food web can have consequences both for community structure and ecosystem processes. However 'change' is not limited to just the number of species in a community, but might include an alteration to such properties as precipitation, nutrient cycling and temperature, all of which are correlated with productivity. Here we argue that predicted scenarios of global change will result in increased plant productivity. We model three scenarios of change using simple Lotka-Volterra dynamics, which explore how a global change in productivity might affect the strength of local species interactions and detail the consequences for community and ecosystem level stability. Our results indicate that (i) at local scales the average population size of consumers may decline because of poor quality food resources, (ii) that the strength of species interactions at equilibrium may become weaker because of reduced population size, and (iii) that species populations may become more variable and may take longer to recover from environmental or anthropogenic disturbances. At local scales interaction strengths encompass such properties as feeding rates and assimilation efficiencies, and encapsulate functionatty important information with regard to ecosystem processes. Interaction strengths represent the pathways and transfer of energy through an ecosystem. We examine how such local patterns might be affected given various scenarios of 'global change' and discuss the consequences for community stability and ecosystem functioning. (C) 2004 Elsevier GmbH. All rights reserved.

Small genetic differences between ericoid mycorrhizal fungi affect nitrogen uptake by Vaccinium

Ericoid mycorrhizal fungi have been shown to differ in their pattern of nitrogen (N) use in pure culture. Here, we investigate whether this functional variation is maintained in symbiosis using three ascomycetes from a clade not previously shown to include ericoid mycorrhizal taxa. Vaccinium macrocarpon and Vaccinium vitis-idaea were inoculated with three fungal strains known to form coils in Vaccinium roots, which differed in their patterns of N use in liquid culture. (15)N was used to trace the uptake of -N, -N and glutamine-N into shoots. (15)N transfer differed among the three fungal strains, including two that had identical internal transcribed spacer (ITS) sequences, and was quantitatively related to fungal growth in liquid culture at low carbon availability. These results demonstrate that functional differences among closely related ericoid mycorrhizal fungi are maintained in symbiosis with their hosts, and suggest that N transfer to plant shoots in ericoid mycorrhizas is under fungal control.

Does Job Search Monitoring Intensity Affect Unemployment? Evidence from Northern Ireland

Because unemployment benefit reforms typically package together a number of changes, few existing evaluations have been able to isolate the effects of changes in job search monitoring intensity on benefit recipient stocks or flows. Those few studies that do so draw mixed conclusions. This paper provides new estimates of monitoring impacts by exploiting plausibly exogenous periods where search monitoring has been temporarily withdrawn - with the regime otherwise unchanged - during a series of benefit office refurbishments in Northern Ireland. As we would expect from search theory, withdrawal of monitoring significantly increases the stock of unemployment benefit recipients via reduced outflows. © The London School of Economics and Political Science 2008.

Antenatal depression and anxiety affect postpartum parenting stress:a longitudinal, prospective study

Postpartum depression has been associated with parenting stress, impacting attachment and child development. However, the relation between antenatal depression or anxiety and postpartum parenting stress has not been investigated. We studied the effect of antenatal depression and anxiety and treatment with selective serotonin reuptake inhibitors and selective norepinephrine reuptake inhibitors (antidepressants [ADs]) on postpartum parenting stress.

Does parenchymal brain injury affect biobehavioral pain responses in very low birth weight infants at 32 weeks' postconceptional age?

Children with neurologic impairments have shown diminished pain response compared with control subjects; however, it remains unclear what mechanisms underlie this response or when it develops. If this were also true with premature infants who undergo neonatal intensive care, then infants with parenchymal brain injury (PBI) would be at increased risk of underrecognition and undertreatment of procedural pain. The purpose of this study was to determine whether infants with PBI display altered responses to acute procedural pain at 32 weeks' postconceptional age (PCA), compared with control subjects.

Does flexibility in secondary level mathematics curriculum affect degree performance?

The authors have much experience in developing mathematics skills of first-year engineering students and attempting to ensure a smooth transition from secondary school to university. Concerns exist due to there being flexibility in the choice of modules needed to obtain a secondary level (A-level) mathematics qualification. This qualification is based on some core (pure maths) modules and a selection from mechanics and statistics modules. A survey of aerospace and mechanical engineering students in Queen’s University Belfast revealed that a combination of both mechanics and statistics (the basic module in both) was by far the most popular choice and therefore only about one quarter of this cohort had studied mechanics beyond the basic module within school maths. Those students who studied the extra mechanics and who achieved top grades at school subsequently did better in two core, first-year engineering courses. However, students with a lower grade from school did not seem to gain any significant advantage in the first-year engineering courses despite having the extra mechanics background. This investigation ties in with ongoing and wider concerns with secondary level mathematics provision in the UK.

'Someone Big and Important': Identification and Affect in an International Development Organization

Psychoanalysis has been widely used to develop our understanding of power in organizations. In this paper, I draw on a case study of a non-profit organization in the field of international development, in order to explore in depth how people engage with powerful discourses at play in this context. I use an ethnographic approach to do so, and find Lacan's ideas on identification and affect to be useful in the analysis of the case. I show how, at first glance, people appeared to readily alter their activities and goals in response to the wishes of an important donor. However, moving deeper to examine identifications on the part of people themselves reveals complex forms of recognition that were inscribed by affective relations. I discuss the implications of these findings for the study of organizations, including the contribution of the concept of affect for studies of identification and subjection in organizations, and the value of ethnographic research approaches that draw upon Lacan's work on recognition.