369 research outputs found

    Fungal proteins with mannanase activity identified directly from a Congo Red stained zymogram by mass spectrometry

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    Secreted fungal proteins with mannanase activity were identified by mass spectrometry of bands excised from a Congo Red stained zymogram containing locust bean gum as substrate. This technique circumvents the need to locate corresponding bands on a parallel gel without substrate and provides good accuracy in targeting proteins for identification. © 2009 Elsevier B.V. All rights reserved

    Inverse-kinematics one-neutron pickup with fast rare-isotope beams

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    New measurements and reaction model calculations are reported for single neutron pickup reactions onto a fast \nuc{22}{Mg} secondary beam at 84 MeV per nucleon. Measurements were made on both carbon and beryllium targets, having very different structures, allowing a first investigation of the likely nature of the pickup reaction mechanism. The measurements involve thick reaction targets and Îł\gamma-ray spectroscopy of the projectile-like reaction residue for final-state resolution, that permit experiments with low incident beam rates compared to traditional low-energy transfer reactions. From measured longitudinal momentum distributions we show that the \nuc{12}{C} (\nuc{22}{Mg},\nuc{23}{Mg}+\gamma)X reaction largely proceeds as a direct two-body reaction, the neutron transfer producing bound \nuc{11}{C} target residues. The corresponding reaction on the \nuc{9}{Be} target seems to largely leave the \nuc{8}{Be} residual nucleus unbound at excitation energies high in the continuum. We discuss the possible use of such fast-beam one-neutron pickup reactions to track single-particle strength in exotic nuclei, and also their expected sensitivity to neutron high-â„“\ell (intruder) states which are often direct indicators of shell evolution and the disappearance of magic numbers in the exotic regime.Comment: 8 pages, 5 figure

    Spectroscopy of 13B via the 13C(t,3He) reaction at 115 AMeV

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    Gamow-Teller and dipole transitions to final states in 13B were studied via the 13C(t,3He) reaction at Et = 115 AMeV. Besides the strong Gamow-Teller transition to the 13B ground state, a weaker Gamow-Teller transition to a state at 3.6 MeV was found. This state was assigned a spin-parity of 3/2- by comparison with shell-model calculations using the WBP and WBT interactions which were modified to allow for mixing between nhw and (n+2)hw configurations. This assignment agrees with a recent result from a lifetime measurement of excited states in 13B. The shell-model calculations also explained the relatively large spectroscopic strength measured for a low-lying 1/2+ state at 4.83 MeV in 13B. The cross sections for dipole transitions up to Ex(13B)= 20 MeV excited via the 13C(t,3He) reaction were also compared with the shell-model calculations. The theoretical cross sections exceeded the data by a factor of about 1.8, which might indicate that the dipole excitations are "quenched". Uncertainties in the reaction calculations complicate that interpretation.Comment: 11 pages, 6 figure

    Correlations in intermediate-energy two-proton removal reactions

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    We report final-state-exclusive measurements of the light charged fragments in coincidence with 26Ne residual nuclei following the direct two-proton removal from a neutron-rich 28Mg secondary beam. A Dalitz-plot analysis and comparisons with simulations show that a majority of the triple- coincidence events with two protons display phase-space correlations consistent with the (two-body) kinematics of a spatially-correlated pair-removal mechanism. The fraction of such correlated events, 56(12) %, is consistent with the fraction of the calculated cross section, 64 %, arising from spin S = 0 two-proton configurations in the entrance-channel (shell-model) 28Mg ground state wave function. This result promises access to an additional and more specific probe of the spin and spatial correlations of valence nucleon pairs in exotic nuclei produced as fast secondary beams.Comment: accepted for publication in Physical Review Letter

    Probing elastic and inelastic breakup contributions to intermediate-energy two-proton removal reactions

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    The two-proton removal reaction from 28Mg projectiles has been studied at 93 MeV/u at the NSCL. First coincidence measurements of the heavy 26Ne projectile residues, the removed protons and other light charged particles enabled the relative cross sections from each of the three possible elastic and inelastic proton removal mechanisms to be determined. These more final-state-exclusive measurements are key for further interrogation of these reaction mechanisms and use of the reaction channel for quantitative spectroscopy of very neutron-rich nuclei. The relative and absolute yields of the three contributing mechanisms are compared to reaction model expectations - based on the use of eikonal dynamics and sd-shell-model structure amplitudes.Comment: Accepted for publication in Physical Review C (Rapid Communication

    Corporate governance and financial constraints on strategic turnarounds

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    The paper extends the Robbins and Pearce (1992) two-stage turnaround response model to include governance factors. In addition to the retrenchment and recovery, the paper proposes the addition of a realignment stage, referring specifically to the re-alignment of expectations of principal and agent groups. The realignment stage imposes a threshold that must be crossed before the retrenchment and hence recovery stage can be entered. Crossing this threshold is problematic to the extent that the interests of governance-stakeholder groups diverge in a crisis situation. The severity of the crisis impacts on the bases of strategy contingent asset valuation leading to the fragmentation of stakeholder interests. In some cases the consequence may be that management are prevented from carrying out turnarounds by governance constraints. The paper uses a case study to illustrate these dynamics, and like the Robbins and Pearce study, it focuses on the textile industry. A longitudinal approach is used to show the impact of the removal of governance constraints. The empirical evidence suggests that such financial constraints become less serious to the extent that there is a functioning market for corporate control. Building on governance research and turnaround literature, the paper also outlines the general case necessary and sufficient conditions for successful turnarounds

    Elastic breakup cross sections of well-bound nucleons

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    The 9Be(28Mg,27Na) one-proton removal reaction with a large proton separation energy of Sp(28Mg)=16.79 MeV is studied at intermediate beam energy. Coincidences of the bound 27Na residues with protons and other light charged particles are measured. These data are analyzed to determine the percentage contributions to the proton removal cross section from the elastic and inelastic nucleon removal mechanisms. These deduced contributions are compared with the eikonal reaction model predictions and with the previously measured data for reactions involving the re- moval of more weakly-bound protons from lighter nuclei. The role of transitions of the proton between different bound single-particle configurations upon the elastic breakup cross section is also quantified in this well-bound case. The measured and calculated elastic breakup fractions are found to be in good agreement.Comment: Phys. Rev. C 2014 (accepted

    The 150^{150}Nd(3^3He,tt) and 150^{150}Sm(tt,3^3He) reactions with applications to ββ\beta\beta decay of 150^{150}Nd

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    The 150^{150}Nd(3^3He,tt) reaction at 140 MeV/u and 150^{150}Sm(tt,3^3He) reaction at 115 MeV/u were measured, populating excited states in 150^{150}Pm. The transitions studied populate intermediate states of importance for the (neutrinoless) ββ\beta\beta decay of 150^{150}Nd to 150^{150}Sm. Monopole and dipole contributions to the measured excitation-energy spectra were extracted by using multipole decomposition analyses. The experimental results were compared with theoretical calculations obtained within the framework of Quasiparticle Random-Phase Approximation (QRPA), which is one of the main methods employed for estimating the half-life of the neutrinoless ββ\beta\beta decay (0νββ0\nu\beta\beta) of 150^{150}Nd. The present results thus provide useful information on the neutrino responses for evaluating the 0νββ0\nu\beta\beta and 2νββ2\nu\beta\beta matrix elements. The 2νββ2\nu\beta\beta matrix element calculated from the Gamow-Teller transitions through the lowest 1+1^{+} state in the intermediate nucleus is maximally about half of that deduced from the half-life measured in 2νββ2\nu\beta\beta direct counting experiments and at least several transitions through 1+1^{+} intermediate states in 150^{150}Pm are required to explain the 2νββ2\nu\beta\beta half-life. Because Gamow-Teller transitions in the 150^{150}Sm(tt,3^3He) experiment are strongly Pauli-blocked, the extraction of Gamow-Teller strengths was complicated by the excitation of the 2ℏω2\hbar\omega, ΔL=0\Delta L=0, ΔS=1\Delta S=1 isovector spin-flip giant monopole resonance (IVSGMR). However, the near absence of Gamow-Teller transition strength made it possible to cleanly identify this resonance, and the strength observed is consistent with the full exhaustion of the non-energy-weighted sum rule for the IVSGMR.Comment: 18 pages, 13 figures, 2 table

    Exploring parents’ understandings of their child’s journey into offending behaviours:a narrative analysis

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    Parents are perhaps the best placed individuals to comment upon their child’s life story, including early life experiences, transitions and their child’s needs. However, research has rarely focussed on the views of parents of young people who have committed serious offences. This research aimed to explore parents’ opinions of which factors may have led to their child becoming involved with the criminal justice system. Interviews were undertaken with six parents who were asked to narrate their child’s life journey into offending behaviours. The data were then analysed using narrative analysis techniques, and a shared story was created which incorporated the main transitional stages in the children’s journeys, as seen by the parents. The findings suggest that it is not just the child, but the whole family who have been in a state of distress throughout the child’s life. Systemic and environmental factors are argued to contribute to this distress, and the use of diagnosis for this population is critically evaluated. The research highlights a life story in which the child’s and family’s distress remains unheard and therefore unresolved. Clinical implications for working with this population are discussed
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