13,258 research outputs found

    Impending anterior ischemic optic neuropathy with elements of retinal vein occlusion in a patient on interferon for polycythemia vera.

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    We describe the course and likely pathophysiology of impending anterior ischemic optic neuropathy (AION) and retinal vein occlusion in a 56-year-old man with polycythemia vera managed with interferon alpha for 2 years. Our patient presented with decreased vision, scintillating scotomata, and floaters. Fundus examination findings and results of a fluorescein angiogram led to the diagnosis of impending AION and retinal vein occlusion. Considering that both polycythemia vera and interferon have possible influences on vascular occlusion and optic disc edema, we stopped interferon treatment and immediately attempted to treat the polycythemia vera empirically with pentoxifylline and any interferon-associated inflammation with prednisone. Our patient experienced complete resolution of fundus abnormalities and return of normal vision within 3 weeks, which may be attributed to our successful treatment of both etiologies. Thus, further study is warranted to elucidate the treatment of both polycythemia vera and interferon-induced impending AION

    Near-BPS Skyrmions: Non-shell configurations and Coulomb effects

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    The relatively small binding energy in nuclei suggests that they may be well represented by near-BPS Skyrmions since their mass is roughly proportional to the baryon number A.A. For that purpose, we propose a generalization of the Skyrme model with terms up to order six in derivatives of the pion fields and treat the nonlinear σ\sigma and Skyrme terms as small perturbations. For our special choice of mass term (or potential) VV, we obtain well-behaved analytical BPS-type solutions with non-shell configurations for the baryon density, as opposed to the more complex shell-like configurations found in most extensions of the Skyrme model . Along with static and (iso)rotational energies, we add to the mass of the nuclei the often neglected Coulomb energy and isospin breaking term. Fitting the four model parameters, we find a remarkable agreement for the binding energy per nucleon B/AB/A with respect to experimental data. These results support the idea that nuclei could be near-BPS Skyrmions.Comment: Correction of minors errors, references adde

    Saying Hello World with UML-RSDS - A Solution to the 2011 Instructive Case

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    In this paper we apply the UML-RSDS notation and tools to the "Hello World" case studies and explain the underlying development process for this model transformation approach.Comment: In Proceedings TTC 2011, arXiv:1111.440

    Solving the TTC 2011 Model Migration Case with UML-RSDS

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    In this paper we apply the UML-RSDS notation and tools to the GMF model migration case study and explain how to use the UML-RSDS tools.Comment: In Proceedings TTC 2011, arXiv:1111.440

    The 2D analogue of the Reissner-Nordstrom solution

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    A two-dimensional (2D) dilaton gravity model, whose static solutions have the same features of the Reissner-Nordstrom solutions, is obtained from the dimensional reduction of a four-dimensional (4D) string effective action invariant under S-duality transformations. The black hole solutions of the 2D model and their relationship with those of the 4D theory are discussed.Comment: 5 pages, Plain-Tex, no figure

    Trust in Science and Scientists and the Acceptance of Evolution

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    Background: Accepting the concept of evolution is important for the advancement of biological science and has many implications for daily life. However, a large portion of the general public does not currently accept biological evolution. Therefore, it is important to understand what factors are associated with a decline in the acceptance of evolution. Of particular interest for us is the relationship of individuals’ sense of trust in science in relationship to evolution acceptance. Methods: Using the Trust in Science and Scientists and Inventory of Student Evolution Acceptance we surveyed 159 undergraduate students enrolled in an introductory psychology course. Additionally, we also asked the students questions regarding their religious commitment and political orientation. To analyze the data we calculated correlations, regressions, and conducted a path analysis. Results: We found that lower levels of trust in science and scientists, stronger religious commitment, and more conservative political orientations were associated with a decrease in the acceptance of evolution in an undergraduate sample. We also found that the results shifted as the contexts for evolution changed. Conclusion: While religious commitment has been previously studied, when combined with levels of both trust in science and scientists and political orientation we gain new insight into how different factors combine to influence evolution acceptance, particularly as the evolution context changes. By understanding how these factors are linked to acceptance of evolution, we may be able to start developing strategies for increasing the acceptance of evolution that are consistent with a range of worldviews

    Intrinsic Pinning in the High Field C-Phase of UPt_3

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    We report on the a.c. magnetic response of superconducting UPt_3 in a d.c. magnetic field. At low fields (H < H^*), the in-phase susceptibility shows a sharp drop at TcT_c followed by a gradual decrease with decreasing temperature, while the out-of-phase component shows a large peak at T_c followed by an unusual broad peak. As the B-C phase line is crossed (H>H^*), however, both the in-phase and out-of-phase susceptibilities resemble the zero-field Meissner curves. We interpret these results in terms of a vortex pinning force which, while comparatively small in the A/B-phases, becomes large enough to effectively prevent vortex motion in the C-phase.Comment: Modified discussion, slight changes to figures, accepted in PRB Rapid Communications. RevTex file, 5 figure

    A multicomponent model of the infrared emission from Comet Halley

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    A model based on a mixture of coated silicates and amorphous carbon grains produces a good spectral match to the available Halley data and is consistent with the compositional and morphological information derived from interplanetary dust particle studies and Halley flyby data. The dark appearance of comets may be due to carbonaceous coatings on the dominant (by mass) silicates. The lack of a 10 micrometer feature may be due to the presence of large silicate grains. The optical properties of pure materials apparently are not representative of cometary materials. The determination of the optical properties of additional silicates and carbonaceous materials would clearly be of use

    DRASTIC—INSIGHTS:querying information in a plant gene expression database

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    DRASTIC––Database Resource for the Analysis of Signal Transduction In Cells (http://www.drastic.org.uk/) has been created as a first step towards a data-based approach for constructing signal transduction pathways. DRASTIC is a relational database of plant expressed sequence tags and genes up- or down-regulated in response to various pathogens, chemical exposure or other treatments such as drought, salt and low temperature. More than 17700 records have been obtained from 306 treatments affecting 73 plant species from 512 peer-reviewed publications with most emphasis being placed on data from Arabidopsis thaliana. DRASTIC has been developed by the Scottish Crop Research Institute and the Abertay University and allows rapid identification of plant genes that are up- or down-regulated by multiple treatments and those that are regulated by a very limited (or perhaps a single) treatment. The INSIGHTS (INference of cell SIGnaling HypoTheseS) suite of web-based tools allows intelligent data mining and extraction of information from the DRASTIC database. Potential response pathways can be visualized and comparisons made between gene expression patterns in response to various treatments. The knowledge gained informs plant signalling pathways and systems biology investigations

    Structure and thermodynamics of colloid-polymer mixtures: a macromolecular approach

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    The change of the structure of concentrated colloidal suspensions upon addition of non-adsorbing polymer is studied within a two-component, Ornstein-Zernicke based liquid state approach. The polymers' conformational degrees of freedom are considered and excluded volume is enforced at the segment level. The polymer correlation hole, depletion layer, and excess chemical potentials are described in agreement with polymer physics theory in contrast to models treating the macromolecules as effective spheres. Known depletion attraction effects are recovered for low particle density, while at higher densities novel many-body effects emerge which become dominant for large polymers.Comment: 7 pages, 4 figures; to be published in Europhys. Let
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