Increasing phosphorus supply is not the mechanism by which arbuscular mycorrhiza increase attractiveness of bean (Vicia faba) to aphids

Peer reviewedPublisher PD

Extremal limits and black hole entropy

Taking the extremal limit of a non-extremal Reissner-Nordstr\"om black hole (by externally varying the mass or charge), the region between the inner and outer event horizons experiences an interesting fate -- while this region is absent in the extremal case, it does not disappear in the extremal limit but rather approaches a patch of $AdS_2\times S^2$. In other words, the approach to extremality is not continuous, as the non-extremal Reissner-Nordstr\"om solution splits into two spacetimes at extremality: an extremal black hole and a disconnected $AdS$ space. We suggest that the unusual nature of this limit may help in understanding the entropy of extremal black holes.Comment: 10 pages, 3 figures. Minor corrections and added reference

Reclaiming Coal Surface Mines in Central Appalachia: A Case Study of the Benefits and Costs

Regulatory alternatives for the surface mining industry have come under intense public and political scrutiny in recent years. Recent studies have found that the impacts of federal surface mine reclamation regulations\u27 will be noticeable, but perhaps not as substantial as some had expected. Nationwide, coal production from surface mines would be reduced by about five percent, with a similar increase in underground coal production. The federal reclamation legislation, depending on the regulations eventually adopted for its implementation, is unlikely to be a major disruptive influence in the coal industry or a substantial impediment to the long-run national goal of increased utilization of coal. This study has found that the social benefits from surface mine reclamation under existing Kentucky regulations unambiguously exceed the private costs. The incremental benefits of reclamation to satisfy the federal regulations which seem likely to be promulgated are always positive and exceed the incremental private costs under some assumptions, but not under others

The contribution of volunteers in social care services for older people

Faced with unprecedented challenges, the adult social care sector in England has seen increasing attention given to the potential of volunteers to contribute to service provision. This article reports the findings of a qualitative study that explored the contribution made by volunteers to social care services for older people. The article draws attention to the difficulties associated with recruiting and training volunteers to work in the sector, particularly during a period of reduced public expenditure, which is putting the sector under strain. Given the challenges faced, the article considers whether it is appropriate to involve volunteers in care work

‘Extra hands’ or the ‘icing on the cake’?:The boundaries of the volunteer role in formal care settings in England

The adult social care sector in England has been encouraged to increase the role of volunteers in service delivery. To understand the volunteer role in care delivery and its impact upon paid care work, we undertook 94 qualitative interviews in seven care settings for older people in England. While the boundaries between care worker and volunteer were clearly established in some organisations, they were more indistinguishable in others. We discuss how both clear and murky boundary making, especially regarding ‘emotional’ and ‘bodily’ aspects of care, can contribute towards paid care work’s invisibility, lack of recognition and poor remuneration

Exploring the role of volunteers in social care for older adults

Purpose This paper aims to report the findings of a study that explores the contribution volunteers make to social care for older adults, identifying lessons for the social care sector and policymakers. Design/methodology/approach An exploratory multiple case study design was used to capture the perspectives and experiences of managers of services, volunteer co-ordinators, volunteers, paid care staff and older people. Seven diverse social care organisations took part in the study drawn from three locations in the South West of England. Findings This study identified three distinct models of volunteer contribution to social care services for older people. Although the contributions made by volunteers to services are valued, the study drew attention to some of the challenges related to their involvement. Research limitations/implications The organisations taking part in this small-scale study were all based in the South West of England, and the findings are therefore not generalisable but contribute to the growing evidence base related to this important field. Practical implications This study demonstrates the importance of the volunteer co-ordinator role and suggests that it is properly funded and resourced. It also confirms the importance of volunteers receiving appropriate training and support. Originality/value Given the increasing involvement of volunteers in the provision of social care, this paper provides lessons to ensure the role of volunteers in social care enhances rather than diminishes the quality of care provided

Dynamical compactification from de Sitter space

We show that D-dimensional de Sitter space is unstable to the nucleation of non-singular geometries containing spacetime regions with different numbers of macroscopic dimensions, leading to a dynamical mechanism of compactification. These and other solutions to Einstein gravity with flux and a cosmological constant are constructed by performing a dimensional reduction under the assumption of q-dimensional spherical symmetry in the full D-dimensional geometry. In addition to the familiar black holes, black branes, and compactification solutions we identify a number of new geometries, some of which are completely non-singular. The dynamical compactification mechanism populates lower-dimensional vacua very differently from false vacuum eternal inflation, which occurs entirely within the context of four-dimensions. We outline the phenomenology of the nucleation rates, finding that the dimensionality of the vacuum plays a key role and that among vacua of the same dimensionality, the rate is highest for smaller values of the cosmological constant. We consider the cosmological constant problem and propose a novel model of slow-roll inflation that is triggered by the compactification process.Comment: Revtex. 41 pages with 24 embedded figures. Minor corrections and added reference

Dietary nitrate increases arginine availability and protects mitochondrial complex I and energetics in the hypoxic rat heart

This is the final version. It was first published by Wiley in The Journal of Physiology at http://onlinelibrary.wiley.com/doi/10.1113/jphysiol.2014.275263/abstract.Hypoxic exposure is associated with impaired cardiac energetics in humans and altered mitochondrial function, with suppressed complex I-supported respiration, in rat heart. This response might limit reactive oxygen species (ROS) generation, but at the cost of impaired electron transport chain (ETC) activity. Dietary nitrate supplementation improves mitochondrial efficiency and can promote tissue oxygenation by enhancing blood flow. We therefore hypothesised that ETC dysfunction, impaired energetics and oxidative damage in the hearts of rats exposed to chronic hypoxia could be alleviated by sustained administration of a moderate dose of dietary nitrate. Male Wistar rats (n=40) were given water supplemented with 0.7 mmol/L NaCl (as control) or 0.7 mmol/L NaNO3, elevating plasma nitrate levels by 80%, and were exposed to 13% O2 (hypoxia) or normoxia (n=10 per group) for 14 days. Respiration rates, ETC protein levels, mitochondrial density, ATP content and protein carbonylation were measured in cardiac muscle. Complex I respiration rates and protein levels were 33% lower in hypoxic/NaCl rats compared with normoxic/NaCl controls. Protein carbonylation was 65% higher in hearts of hypoxic rats compared with controls, indicating increased oxidative stress, whilst ATP levels were 62% lower. Respiration rates, complex I protein and activity, protein carbonylation and ATP levels were all fully protected in the hearts of nitrate-supplemented hypoxic rats. Both in normoxia and hypoxia, dietary nitrate suppressed cardiac arginase expression and activity and markedly elevated cardiac L-arginine concentrations, unmasking a novel mechanism of action by which nitrate enhances tissue NO bioavailability. Dietary nitrate therefore alleviates metabolic abnormalities in the hypoxic heart, improving myocardial energetics

Similarity-based interference during language comprehension: Evidence from eye tracking during reading.

The nature of working memory operation during complex sentence comprehension was studied using eye-tracking methodology. Readers had difficulty when the syntax of a sentence required them to hold two similar noun phrases (NPs) in working memory before syntactically and semantically integrating either of the NPs with a verb. In sentence structures that placed these NPs at the same linear distances from one another but allowed integration with a verb for one of the NPs, the comprehension difficulty was not seen. These results are interpreted as indicating that similarity-based interference occurs online during the comprehension of complex sentences and that the degree of memory accessibility conventionally associated with different types of NPs does not have a strong effect on sentence processing