Spatial ecology of white-clawed crayfish Austropotamobius pallipes and signal crayfish Pacifastacus leniusculus in upland rivers, Northern England

The American signal crayfish Pacifastacus lernusculus, an invasive species widely introduced throughout Europe, is a major threat to native European crayfish species and is causing increasing concern because of its wide impact on aquatic ecosystems. This thesis investigates the within catchment expansion of signal crayfish populations in two upland rivers and the spatial ecology and movement of the introduced signal crayfish and the indigenous white-clawed crayfish Austropotamobius pallipes. Populations of signal crayfish are established and expanding on the upland rivers Wharfe and Ure. On the Wharfe the signal crayfish population is well established and now occupies about 30 km of river and is currently expanding at a rate in excess of 2 km year(^-1). On the Ure the signal crayfish population is younger and currently occupies 1.6 km and is currently expanding at about 0.5 km year(^-1). The range expansion is biased towards downstream in both rivers, by a ratio of about 3:1 (downstream:upstream).The movements and dispersal of white-clawed and signal crayfish was studied utilising a combination of radiotelemetry and internal and external Passive Integrated Transponder (PIT) tags. Radiotagged adult signal crayfish were capable of substantial active movements (maximum movement 790m in 79 days). The level of movement of adults suggests they may have the potential to be responsible for the observed rates of population expansion. Although the movements of radiotagged adult signal crayfish within main river channel were equally distributed upstream and downstream, in-stream barriers both natural and artificial were found to limit the upstream movements of PIT tagged crayfish and this may contribute to the observed downstream bias of signal crayfish population expansion. The movements and dispersal of PIT tagged white-clawed crayfish within a small upland high gradient stream were strongly biased towards downstream. Maximum movement of radiotagged adult signal crayfish occurred during midsummer. Temperature appeared to be a major factor influencing the timing and extent of movements between tracking periods although there was a large variation between individuals. All significant downstream movements made by crayfish were active movements and not the result of passive movement during periods of high discharge. There were no sex or size differences in the dispersal and movement of radiotagged and PIT tagged signal crayfish whilst in PIT tagged white-clawed crayfish size, sex, injuries and duration of tracking influenced extent of movement. The expansion of the signal crayfish population in the River Wharfe appears to lead to the progressive loss of white-clawed crayfish populations where they come into direct contact. Limited differences in the microhabitat utilised by the two species were found where the species were syntopic, suggesting the potential exists for direct competition between the two species. In addition signal crayfish showed greater movement and dispersal than white-clawed crayfish. This may contribute to the ability of signal crayfish to colonise rivers rapidly and may also offer a competitive advantage over white-clawed crayfish thus contributing to the observed replacement. The results are discussed in the context of the conservation and management of crayfish and the ecology of invasive species

Supporting induction: relationships count

This article examines the structural changes to the induction of teachers in Scotland using the perceptions of a group of final year student teachers. This group would be the first probationer teachers to experience revised arrangements for new teacher induction in 37 years. Their preferences and concerns are highlighted, as the new procedures roll out in schools nationwide, in an attempt to stress the importance of relationships to the success of the induction scheme. The argument put forward in this article is based on the notion that personal intelligence is central to effective relationships and therefore crucially important in the context of this mentoring relationship. The views of our sample provide evidence to suggest that the quality of interactions between the mentor and the probationer teacher are paramount in providing a good induction experience. These views are substantiated by experiences in England and in induction literature elsewhere. A synthesis of this evidence is used to make recommendations for those involved in supporting induction in schools, local authorities or teacher education institutions

Upregulated miR-146a expression in peripheral blood mononuclear cells from rheumatoid arthritis patients

Introduction MicroRNAs are small noncoding RNA molecules that negatively regulate gene expression via degradation or translational repression of their targeted mRNAs. It is known that aberrant microRNA expression can play important roles in cancer, but the role of microRNAs in autoimmune diseases is only beginning to emerge. In this study, the expression of selected microRNAs is examined in rheumatoid arthritis. Methods Total RNA was isolated from peripheral blood mononuclear cells obtained from patients with rheumatoid arthritis, and healthy and disease control individuals, and the expression of miR-146a, miR-155, miR-132, miR-16, and microRNA let-7a was analyzed using quantitative real-time PCR. Results Rheumatoid arthritis peripheral blood mononuclear cells exhibited between 1.8-fold and 2.6-fold increases in miR-146a, miR-155, miR-132, and miR-16 expression, whereas let-7a expression was not significantly different compared with healthy control individuals. In addition, two targets of miR-146a, namely tumor necrosis factor receptor-associated factor 6 (TRAF6) and IL-1 receptor-associated kinase 1 (IRAK-1), were similarly expressed between rheumatoid arthritis patients and control individuals, despite increased expression of miR-146a in patients with rheumatoid arthritis. Repression of TRAF6 and/or IRAK-1 in THP-1 cells resulted in up to an 86% reduction in tumor necrosis factor-α production, implicating that normal miR-146a function is critical for the regulation of tumor necrosis factor-α production. Conclusions Recent studies have shown that synovial tissue and synovial fibroblasts from patients with rheumatoid arthritis exhibit increased expression of certain microRNAs. Our data thus demonstrate that microRNA expression in rheumatoid arthritis peripheral blood mononuclear cells mimics that of synovial tissue/fibroblasts. The increased microRNA expression in rheumatoid arthritis patients is potentially useful as a marker for disease diagnosis, progression, or treatment efficacy, but this will require confirmation using a large and well defined cohort. Our data also suggest a possible mechanism contributing to rheumatoid arthritis pathogenesis, whereby miR-146a expression is increased but unable to properly function, leading to prolonged tumor necrosis factor-α production in patients with rheumatoid arthritis

A TOMM40 poly-T variant modulates gene expression and is associated with vocabulary ability and decline in nonpathologic aging

The Translocase of Outer Mitochondrial Membrane 40 Homolog and Apolipoprotein E (TOMM40-APOE) locus has been associated with a number of age-related phenotypes in humans including nonpathologic cognitive aging, late-onset Alzheimer's disease, and longevity. Here, we investigate the influence of the TOMM40 intron 6 poly-T variant (rs10524523) on TOMM40 gene expression and cognitive abilities and decline in a cohort of 1613 community-dwelling elderly volunteers who had been followed for changes in cognitive functioning over a period of 14 years (range = 12–18 years). We showed that the shorter length poly-T variants were found to act as a repressor of luciferase gene expression in reporter gene constructs. Expression was reduced to approximately half of that observed for the very long variant. We further observed that the shorter poly-T variant was significantly associated with reduced vocabulary ability and a slower rate of vocabulary decline with age compared to the very long poly-T variants. No significant associations were observed for memory, fluid intelligence or processing speed, although the direction of effect, where the short variant was correlated with reduced ability and slower rate of decline was observed for all tests. Our results indicate that the poly-T variant has the ability to interact with transcription machinery and differentially modulate reporter gene expression and influence vocabulary ability and decline with age

Fatigue evaluation in maintenance and assembly operations by digital human simulation

Virtual human techniques have been used a lot in industrial design in order to consider human factors and ergonomics as early as possible. The physical status (the physical capacity of virtual human) has been mostly treated as invariable in the current available human simulation tools, while indeed the physical capacity varies along time in an operation and the change of the physical capacity depends on the history of the work as well. Virtual Human Status is proposed in this paper in order to assess the difficulty of manual handling operations, especially from the physical perspective. The decrease of the physical capacity before and after an operation is used as an index to indicate the work difficulty. The reduction of physical strength is simulated in a theoretical approach on the basis of a fatigue model in which fatigue resistances of different muscle groups were regressed from 24 existing maximum endurance time (MET) models. A framework based on digital human modeling technique is established to realize the comparison of physical status. An assembly case in airplane assembly is simulated and analyzed under the framework. The endurance time and the decrease of the joint moment strengths are simulated. The experimental result in simulated operations under laboratory conditions confirms the feasibility of the theoretical approach