5,003 research outputs found

    Human resourcing in academic libraries : the 'lady librarian', the call for flexible staff and the need to be counted

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    This paper reports on a recent set of research findings into human resource (HR) deployment in academic, college and national libraries in the UK and Ireland by selectively summarising these findings. The recommendations are that libraries should make available for comparison by others not only their library service provision, i.e. opening hours, but also staff provision, i.e. staffing numbers and demographics and staff deployment, with a view to benchmarking levels of flexibility. This work highlights the lack of existing benchmarking facilities in UK universities and colleges of higher education, relating to HR deployment in libraries, and recommends that Sconul extends the existing data collection in its Annual Statistical return to include this HR area

    Gene expression analysis of bovine embryonic disc, trophoblast and parietal hypoblast at the start of gastrulation

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    In cattle early gastrulation-stage embryos (Stage 5), four tissues can be discerned: (i) the top layer of the embryonic disc consisting of embryonic ectoderm (EmE); (ii) the bottom layer of the disc consisting of mesoderm, endoderm and visceral hypoblast (MEH); (iii) the trophoblast (TB); and (iv) the parietal hypoblast. We performed microsurgery followed by RNA-seq to analyse the transcriptome of these four tissues as well as a developmentally earlier pre-gastrulation embryonic disc. The cattle EmE transcriptome was similar at Stages 4 and 5, characterised by the OCT4/SOX2/NANOG pluripotency network. Expression of genes associated with primordial germ cells suggest their presence in the EmE tissue at these stages. Anterior visceral hypoblast genes were transcribed in the Stage 4 disc, but no longer by Stage 5. The Stage 5 MEH layer was equally similar to mouse embryonic and extraembryonic visceral endoderm. Our data suggest that the first mesoderm to invaginate in cattle embryos is fated to become extraembryonic. TGFβ, FGF, VEGF, PDGFA, IGF2, IHH and WNT signals and receptors were expressed, however the representative members of the FGF families differed from that seen in equivalent tissues of mouse embryos. The TB transcriptome was unique and differed significantly from that of mice. FGF signalling in the TB may be autocrine with both FGFR2 and FGF2 expressed. Our data revealed a range of potential inter-tissue interactions, highlighted significant differences in early development between mice and cattle and yielded insight into the developmental events occurring at the start of gastrulation

    Spin-Dependent Tunneling of Single Electrons into an Empty Quantum Dot

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    Using real-time charge sensing and gate pulsing techniques we measure the ratio of the rates for tunneling into the excited and ground spin states of a single-electron AlGaAs/GaAs quantum dot in a parallel magnetic field. We find that the ratio decreases with increasing magnetic field until tunneling into the excited spin state is completely suppressed. However, we find that by adjusting the voltages on the surface gates to change the orbital configuration of the dot we can restore tunneling into the excited spin state and that the ratio reaches a maximum when the dot is symmetric.Comment: 4 pages, 3 figure

    Electrical control of spin relaxation in a quantum dot

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    We demonstrate electrical control of the spin relaxation time T_1 between Zeeman split spin states of a single electron in a lateral quantum dot. We find that relaxation is mediated by the spin-orbit interaction, and by manipulating the orbital states of the dot using gate voltages we vary the relaxation rate W= (T_1)^-1 by over an order of magnitude. The dependence of W on orbital confinement agrees with theoretical predictions and from these data we extract the spin-orbit length. We also measure the dependence of W on magnetic field and demonstrate that spin-orbit mediated coupling to phonons is the dominant relaxation mechanism down to 1T, where T_1 exceeds 1s.Comment: 4 pages, 3 figure

    Detection of solvents using a distributed fibre optic sensor

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    A fibre optic sensor that is capable of distributed detection of liquid solvents is presented. Sensor interrogation using optical time domain reflectometry (OTDR) provides the capability of locating solvent spills to a precision of ±2 m over a total sensor length that may extend to 20 km

    Energy Dependent Tunneling in a Quantum Dot

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    We present measurements of the rates for an electron to tunnel on and off a quantum dot, obtained using a quantum point contact charge sensor. The tunnel rates show exponential dependence on drain-source bias and plunger gate voltages. The tunneling process is shown to be elastic, and a model describing tunneling in terms of the dot energy relative to the height of the tunnel barrier quantitatively describes the measurements.Comment: 4 pages, 4 figure

    Spectroscopy of 50^{50}Sc and ab initio calculations of B(M3)B(M3) strengths

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    The GRIFFIN spectrometer at TRIUMF-ISAC has been used to study excited states and transitions in 50^{50}Sc following the β\beta-decay of 50^{50}Ca. Branching ratios were determined from the measured γ\gamma-ray intensities, and angular correlations of γ\gamma rays have been used to firmly assign the spins of excited states. The presence of an isomeric state that decays by an M3M3 transition with a B(M3)B(M3) strength of 13.6(7)\,W.u. has been confirmed. We compare with the first {\it ab initio} calculations of B(M3B(M3) strengths in light and medium-mass nuclei from the valence-space in-medium similarity renormalization group approach, using consistently derived effective Hamiltonians and M3M3 operator. The experimental data are well reproduced for isoscalar M3M3 transitions when using bare gg-factors, but the strength of isovector M3M3 transitions are found to be underestimated by an order of magnitude
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