1,597 research outputs found

    The effect of beam-driven return current instability on solar hard X-ray bursts

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    The problem of electrostatic wave generation by a return current driven by a small area electron beam during solar hard X-ray bursts is discussed. The marginal stability method is used to solve numerically the electron and ion heating equations for a prescribed beam current evolution. When ion-acoustic waves are considered, the method appears satisfactory and, following an initial phase of Coulomb resistivity in which T sub e/T sub i rise, predicts a rapid heating of substantial plasma volumes by anomalous ohmic dissipation. This hot plasma emits so much thermal bremsstrahlung that, contrary to previous expectations, the unstable beam-plasma system actually emits more hard X-rays than does the beam in the purely collisional thick target regime relevant to larger injection areas. Inclusion of ion-cyclotron waves results in ion-acoustic wave onset at lower T sub e/T sub i and a marginal stability treatment yields unphysical results

    Cromwell's Edinburgh press and the development of print culture in Scotland

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    Alasdair Mann, the noted scholar of book culture in early modern Scotland, has suggested that a significant change had occurred in Scotland's relationship with the printed word by the late seventeenth century. This study sets out to explain how the interregnum served as a ‘watershed’ during which a consumer demand was created for popular print and how this in turn necessitated a significant increase in the production and distribution of printed material. Beginning with the sale of the press and patent of Evan Tyler to the London Stationers’ Company in 1647, the article charts the key factors that transformed Scotland's printing industry from the production of official declarations and works for foreign markets to the production of polemical texts for a Scottish audience. These developments also witnessed publication of the first serial news journal and the growth of a competitive market for up-to-date printed news. More than just an anomaly that flourished during a decade of occupation, these fundamental changes altered Scotland by introducing the large-scale consumption of chapbooks and printed ephemera, thereby initiating the nation's enduring print culture

    Mipomersen preferentially reduces small low-density lipoprotein particle number in patients with hypercholesterolemia

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    AbstractBackgroundBecause of variability in lipoprotein cholesterol content, low-density lipoprotein (LDL) cholesterol frequently underrepresents or overrepresents the number of LDL particles. Mipomersen is an antisense oligonucleotide that reduces hepatic production of apolipoprotein B–100, the sole apolipoprotein of LDL.ObjectiveTo characterize the effects of mipomersen on lipoprotein particle numbers as well as subclass distribution using nuclear magnetic resonance (NMR) spectroscopy.MethodsWe compared the tertiary results for the direct measurement of LDL particle numbers by NMR among 4 placebo-controlled, phase 3 studies of mipomersen that had similar study designs but different patient populations: homozygous familial hypercholesterolemia (HoFH), severe hypercholesterolemia, heterozygous familial hypercholesterolemia with established coronary artery disease, or hypercholesterolemia with high risk for coronary heart disease (HC-CHD).ResultsHoFH patients had the highest median total LDL particles at baseline compared with HC-CHD patients, who had the lowest. At baseline, the HoFH population uniquely had a greater mean percentage of large LDL particles (placebo, 60.2%; mipomersen, 54.9%) compared with small LDL particles (placebo, 33.1%; mipomersen, 38.9%). In all 4 studies, mipomersen was associated with greater reductions from baseline in the concentrations of small LDL particles compared with those of large LDL particles, and both total LDL particles and small LDL particles were statistically significantly reduced.ConclusionsMipomersen consistently reduced all LDL particle numbers and preferentially reduced the concentration of small LDL particles in all 4 phase 3 studies

    Remote Hiring Innovation During the COVID-19 Pandemic

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    Extension\u27s in-person hiring processes have been complicated in 2020 by the COVID-19 pandemic. To prevent delays in hiring for three vacant county faculty positions, our search committee conducted remote interviews using a variety of innovative techniques, such as a live we\u27re hiring webinar, an icebreaker session, and live and recorded candidate presentations. The results of our innovative efforts included a larger pool of applicants, relaxed web-based video interviews, and savings in time and expenses. These strategies could be considered as new and effective approaches and practices to hiring and interviewing in Extension as the pandemic continues and into the future

    Elastic energy of polyhedral bilayer vesicles

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    In recent experiments [M. Dubois, B. Dem\'e, T. Gulik-Krzywicki, J.-C. Dedieu, C. Vautrin, S. D\'esert, E. Perez, and T. Zemb, Nature (London) Vol. 411, 672 (2001)] the spontaneous formation of hollow bilayer vesicles with polyhedral symmetry has been observed. On the basis of the experimental phenomenology it was suggested [M. Dubois, V. Lizunov, A. Meister, T. Gulik-Krzywicki, J. M. Verbavatz, E. Perez, J. Zimmerberg, and T. Zemb, Proc. Natl. Acad. Sci. U.S.A. Vol. 101, 15082 (2004)] that the mechanism for the formation of bilayer polyhedra is minimization of elastic bending energy. Motivated by these experiments, we study the elastic bending energy of polyhedral bilayer vesicles. In agreement with experiments, and provided that excess amphiphiles exhibiting spontaneous curvature are present in sufficient quantity, we find that polyhedral bilayer vesicles can indeed be energetically favorable compared to spherical bilayer vesicles. Consistent with experimental observations we also find that the bending energy associated with the vertices of bilayer polyhedra can be locally reduced through the formation of pores. However, the stabilization of polyhedral bilayer vesicles over spherical bilayer vesicles relies crucially on molecular segregation of excess amphiphiles along the ridges rather than the vertices of bilayer polyhedra. Furthermore, our analysis implies that, contrary to what has been suggested on the basis of experiments, the icosahedron does not minimize elastic bending energy among arbitrary polyhedral shapes and sizes. Instead, we find that, for large polyhedron sizes, the snub dodecahedron and the snub cube both have lower total bending energies than the icosahedron

    Offenders' Crime Narratives across Different Types of Crimes

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    The current study explores the roles offenders see themselves playing during an offence and their relationship to different crime types. One hundred and twenty incarcerated offenders indicated the narrative roles they acted out whilst committing a specific crime they remembered well. The data were subjected to Smallest Space Analysis (SSA) and four themes were identified: Hero, Professional, Revenger and Victim in line with the recent theoretical framework posited for Narrative Offence Roles (Youngs & Canter, 2012). Further analysis showed that different subsets of crimes were more like to be associated with different narrative offence roles. Hero and Professional were found to be associated with property offences (theft, burglary and shoplifting), drug offences and robbery and Revenger and Victim were found to be associated with violence, sexual offences and murder. The theoretical implications for understanding crime on the basis of offenders' narrative roles as well as practical implications are discussed
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