Vibrational Enhancement of the Effective Donor - Acceptor Coupling

The paper deals with a simple three sites model for charge transfer phenomena in an one-dimensional donor (D) - bridge (B) - acceptor (A) system coupled with vibrational dynamics of the B site. It is found that in a certain range of parameters the vibrational coupling leads to an enhancement of the effective donor - acceptor electronic coupling as a result of the formation of the polaron on the B site. This enhancement of the charge transfer efficiency is maximum at the resonance, where the effective energy of the fluctuating B site coincides with the donor (acceptor) energy.Comment: 5 pages, 3 figure

Molecular Genetics of T Cell Development

T cell development is guided by a complex set of transcription factors that act recursively, in different combinations, at each of the developmental choice points from T-lineage specification to peripheral T cell specialization. This review describes the modes of action of the major T-lineage-defining transcription factors and the signal pathways that activate them during intrathymic differentiation from pluripotent precursors. Roles of Notch and its effector RBPSuh (CSL), GATA-3, E2A/HEB and Id proteins, c-Myb, TCF-1, and members of the Runx, Ets, and Ikaros families are critical. Less known transcription factors that are newly recognized as being required for T cell development at particular checkpoints are also described. The transcriptional regulation of T cell development is contrasted with that of B cell development, in terms of their different degrees of overlap with the stem-cell program and the different roles of key transcription factors in gene regulatory networks leading to lineage commitment

'It would be easier if she’d died’: young people with parents with dementia articulating inadmissible stories

In the U.K. context where the emphasis is (quite rightly) on living well with dementia, on positivity and enabling approaches, it can be difficult for researchers to investigate and report negative experiences. Failing to re-present perceptions and experiences as they are lived, however, does a serious disservice to the research endeavor and can prevent policy and service development and positive change. In this article, we present some stories told by participants in an Alzheimer’s Society (United Kingdom) Funded project uniquely investigating the perceptions and experiences of children and young people who have a parent with dementia. Sometimes the stories were not easy to hear, especially when they challenged dominant master narratives around dementia. We discuss our view that when the young people we spoke with told us how things were for them, we were ethically bound to respect and disseminate their accounts

Superconductivity coexisting with phase-separated static magnetic order in (Ba,K)Fe2_{2}As2_{2}, (Sr,Na)Fe2_{2}As2_{2} and CaFe2_{2}As2_{2}

The recent discovery and subsequent developments of FeAs-based superconductors have presented novel challenges and opportunities in the quest for superconducting mechanisms in correlated-electron systems. Central issues of ongoing studies include interplay between superconductivity and magnetism as well as the nature of the pairing symmetry reflected in the superconducting energy gap. In the cuprate and RE(O,F)FeAs (RE = rare earth) systems, the superconducting phase appears without being accompanied by static magnetic order, except for narrow phase-separated regions at the border of phase boundaries. By muon spin relaxation measurements on single crystal specimens, here we show that superconductivity in the AFe$_{2}$As$_{2}$ (A = Ca,Ba,Sr) systems, in both the cases of composition and pressure tunings, coexists with a strong static magnetic order in a partial volume fraction. The superfluid response from the remaining paramagnetic volume fraction of (Ba$_{0.5}$K$_{0.5}$)Fe$_{2}$As$_{2}$ exhibits a nearly linear variation in T at low temperatures, suggesting an anisotropic energy gap with line nodes and/or multi-gap effects.Comment: 14 pages 7 figures (4 for main text and 3 for on-line supplementary documents

Methodological approaches to determining the marine radiocarbon reservoir effect

The marine radiocarbon reservoir effect is an offset in 14C age between contemporaneous organisms from the terrestrial environment and organisms that derive their carbon from the marine environment. Quantification of this effect is of crucial importance for correct calibration of the <sup>14</sup>C ages of marine-influenced samples to the calendrical timescale. This is fundamental to the construction of archaeological and palaeoenvironmental chronologies when such samples are employed in <sup>14</sup>C analysis. Quantitative measurements of temporal variations in regional marine reservoir ages also have the potential to be used as a measure of process changes within Earth surface systems, due to their link with climatic and oceanic changes. The various approaches to quantification of the marine radiocarbon reservoir effect are assessed, focusing particularly on the North Atlantic Ocean. Currently, the global average marine reservoir age of surface waters, R(t), is c. 400 radiocarbon years; however, regional values deviate from this as a function of climate and oceanic circulation systems. These local deviations from R(t) are expressed as +R values. Hence, polar waters exhibit greater reservoir ages (δR = c. +400 to +800 <sup>14</sup>C y) than equatorial waters (δR = c. 0 <sup>14</sup>C y). Observed temporal variations in δR appear to reflect climatic and oceanographic changes. We assess three approaches to quantification of marine reservoir effects using known age samples (from museum collections), tephra isochrones (present onshore/offshore) and paired marine/terrestrial samples (from the same context in, for example, archaeological sites). The strengths and limitations of these approaches are evaluated using examples from the North Atlantic region. It is proposed that, with a suitable protocol, accelerator mass spectrometry (AMS) measurements on paired, short-lived, single entity marine and terrestrial samples from archaeological deposits is the most promising approach to constraining changes over at least the last 5 ky BP

Am I just not good enough? The creation, development and questioning of a high performance coaching identity

While the career experiences and trajectories of various sports workers have received increased scholarly attention, those of professional coaches have, in comparison, received scant consideration. This paper focuses on the career experiences of Maeve (a pseudonym), a high performance coach, and the critical incidents related to the creation, development, and, ultimately, questioning of her professional identity. Data were collected through a series of narrative-biographical interviews and were subject to a process of iterative data analysis. The results indicated that her significant investment into her coaching self, combined with the vagaries and uncertain nature of work in high performance coaching, led her to experience a biographical disruption that interrupted the narrative coherence of her coaching life. The findings add further credence to recent critiques of only understanding and representing coaching careers in a linear and chronically staged fashion

Animal movements in the Kenya Rift and evidence for the earliest ambush hunting by hominins

Animal movements in the Kenya Rift Valley today are influenced by a combination of topography and trace nutrient distribution. These patterns would have been the same in the past when hominins inhabited the area. We use this approach to create a landscape reconstruction of Olorgesailie, a key site in the East African Rift with abundant evidence of large-mammal butchery between ~1.2 and ~0.5 Ma BP. The site location in relation to limited animal routes through the area show that hominins were aware of animal movements and used the location for ambush hunting during the Lower to Middle Pleistocene. These features explain the importance of Olorgesailie as a preferred location of repeated hominin activity through multiple changes in climate and local environmental conditions, and provide insights into the cognitive and hunting abilities of Homo erectus while indicating that their activities at the site were aimed at hunting, rather than scavenging

Endocytosis of DNA-Hsp65 Alters the pH of the Late Endosome/Lysosome and Interferes with Antigen Presentation

BACKGROUND: Experimental models using DNA vaccine has shown that this vaccine is efficient in generating humoral and cellular immune responses to a wide variety of DNA-derived antigens. Despite the progress in DNA vaccine development, the intracellular transport and fate of naked plasmid DNA in eukaryotic cells is poorly understood, and need to be clarified in order to facilitate the development of novel vectors and vaccine strategies. METHODOLOGY AND PRINCIPAL FINDINGS: Using confocal microscopy, we have demonstrated for the first time that after plasmid DNA uptake an inhibition of the acidification of the lysosomal compartment occurs. This lack of acidification impaired antigen presentation to CD4 T cells, but did not alter the recruitment of MyD88. The recruitment of Rab 5 and Lamp I were also altered since we were not able to co-localize plasmid DNA with Rab 5 and Lamp I in early endosomes and late endosomes/lysosomes, respectively. Furthermore, we observed that the DNA capture process in macrophages was by clathrin-mediated endocytosis. In addition, we observed that plasmid DNA remains in vesicles until it is in a juxtanuclear location, suggesting that the plasmid does not escape into the cytoplasmic compartment. CONCLUSIONS AND SIGNIFICANCE: Taken together our data suggests a novel mechanism involved in the intracellular trafficking of plasmid DNA, and opens new possibilities for the use of lower doses of plasmid DNA to regulate the immune response

A next-generation sequencing method for overcoming the multiple gene copy problem in polyploid phylogenetics, applied to Poa grasses

<p>Abstract</p> <p>Background</p> <p>Polyploidy is important from a phylogenetic perspective because of its immense past impact on evolution and its potential future impact on diversification, survival and adaptation, especially in plants. Molecular population genetics studies of polyploid organisms have been difficult because of problems in sequencing multiple-copy nuclear genes using Sanger sequencing. This paper describes a method for sequencing a barcoded mixture of targeted gene regions using next-generation sequencing methods to overcome these problems.</p> <p>Results</p> <p>Using 64 3-bp barcodes, we successfully sequenced three chloroplast and two nuclear gene regions (each of which contained two gene copies with up to two alleles per individual) in a total of 60 individuals across 11 species of Australian <it>Poa </it>grasses. This method had high replicability, a low sequencing error rate (after appropriate quality control) and a low rate of missing data. Eighty-eight percent of the 320 gene/individual combinations produced sequence reads, and >80% of individuals produced sufficient reads to detect all four possible nuclear alleles of the homeologous nuclear loci with 95% probability.</p> <p>We applied this method to a group of sympatric Australian alpine <it>Poa </it>species, which we discovered to share an allopolyploid ancestor with a group of American <it>Poa </it>species. All markers revealed extensive allele sharing among the Australian species and so we recommend that the current taxonomy be re-examined. We also detected hypermutation in the <it>trn</it>H-<it>psb</it>A marker, suggesting it should not be used as a land plant barcode region. Some markers indicated differentiation between Tasmanian and mainland samples. Significant positive spatial genetic structure was detected at <100 km with chloroplast but not nuclear markers, which may be a result of restricted seed flow and long-distance pollen flow in this wind-pollinated group.</p> <p>Conclusions</p> <p>Our results demonstrate that 454 sequencing of barcoded amplicon mixtures can be used to reliably sample all alleles of homeologous loci in polyploid species and successfully investigate phylogenetic relationships among species, as well as to investigate phylogeographic hypotheses. This next-generation sequencing method is more affordable than and at least as reliable as bacterial cloning. It could be applied to any experiment involving sequencing of amplicon mixtures.</p

Sports coaches as ‘dangerous individuals’ - practice as governmentality

This is an Accepted Manuscript of an article published by Taylor & Francis in Sport, Education and Society on 31/03/2014, available online: doi: 10.1080/13573322.2014.899492Recent concern surrounding sports coaches’ interaction with young people has reflected a fundamental change in the way coaches and others regard the role of sports. In this paper, we consider the identification and definition of the contemporary sports coach (whether acting in a professional or volunteer capacity) as, in Foucault’s term, a ‘dangerous individual’. We suggest that the mainstream discourse of child protection and safeguarding, variously interpreted and applied, has contributed to a culture of fear in sports coaching practice. Drawing on data from a recently completed Economic and Social Research Council-funded research project, we argue that contradictions in policy and practice, which serve to privilege a particular discourse, have cast the coach as both predator and protector of young sports performers. This has undermined the role of the coach, led to intergenerational fear, created doubt about coaches’ intentions and promoted their adoption of defensive and protective practices. Utilising the concept of governmentality, we argue that, as a consequence, fundamental trust-based relationships, necessary in healthy athlete−coach engagement, have been displaced by a discourse embodied in sterile delivery and procedure governed by regulation and suspicion