3,397 research outputs found

    Some variations on RSA signatures & their security

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    Evaluation "Angels and Demons" (WP-116)

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    One way to generate the money needed for sustainable innovation is by consumer choosing freely for sustainable products. This way, consumer choice pays for the innovative production method. This requires consumer willingness to buy these products. Willingness to buy is however not so easily measured as the intentions to buy may only partially predict actual purchase behaviour. There is a gap between what consumer say they want, and what they do in practice. For the specific case of sustainable production, consumers often say they are very positive about sustainable products (angelic opinion), yet in their daily behaviour they frequently tend to choose convenient and cheap products (demonic behaviour)

    Onset and Recurrence of Depression as Predictors of Cardiovascular Prognosis in Depressed Acute Coronary Syndrome Patients:A Systematic Review

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    Background: Depression after acute coronary syndrome (ACS) is associated with worse cardiac outcomes. This systematic review evaluated whether depressed ACS patients are at differential risk depending on the recurrence and timing of onset of depressive episodes. Methods: MEDLINE, EMBASE and PsycINFO were searched from inception to 11 April 2009. Additionally, reference lists and recent tables of contents of 34 selected journals were manually searched. Eligible studies evaluated cardiovascular outcomes for subgroups of ACS patients with depression or depressive symptoms according to recurrence or onset. Results: Six studies were included that reported outcomes for subgroups of ACS patients with first-ever versus recurrent depression. Four of these reported also outcomes for post-ACS onset versus pre-ACS onset depression, and incident versus nonincident depression. Worse outcomes (odds ratio &gt;1.4) were reported for ACS patients with first-ever depression in 3 of 6 studies (1 study p &lt;0.05), for patients with post-ACS onset depression in 3 of 4 studies (1 study p &lt;0.05, but better outcomes in one study) and for patients with incident depression in 2 of 4 studies (no studies p &lt;0.05). Conclusions: Although it is still suggested that ACS patients with first and new-onset depression are at particularly increased risk of worse prognosis, the inconsistent results from the studies included in this systematic review show that there is no consistent evidence to support such statements. Copyright (C) 2011 S. Karger AG, Basel</p

    High temporal-resolution scanning transmission electron microscopy using sparse-serpentine scan pathways

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    Scanning transmission electron microscopy (STEM) provides structural analysis with sub-angstrom resolution. But the pixel-by-pixel scanning process is a limiting factor in acquiring high-speed data. Different strategies have been implemented to increase scanning speeds while at the same time minimizing beam damage via optimizing the scanning strategy. Here, we achieve the highest possible scanning speed by eliminating the image acquisition dead time induced by the beam flyback time combined with reducing the amount of scanning pixels via sparse imaging. A calibration procedure was developed to compensate for the hysteresis of the magnetic scan coils. A combination of sparse and serpentine scanning routines was tested for a crystalline thin film, gold nanoparticles, and in an in-situ liquid phase STEM experiment. Frame rates of 92, 23 and 5.8 s-1 were achieved for images of a width of 128, 256, and 512 pixels, respectively. The methods described here can be applied to single-particle tracking and analysis of radiation sensitive materials

    Structural and magnetic properties of Fe/ZnSe(001) interfaces

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    We have performed first principles electronic structure calculations to investigate the structural and magnetic properties of Fe/ZnSe(001) interfaces. Calculations involving full geometry optimizations have been carried out for a broad range of thickness of Fe layers(0.5 monolayer to 10 monolayers) on top of a ZnSe(001) substrate. Both Zn and Se terminated interfaces have been explored. Total energy calculations show that Se segregates at the surface which is in agreement with recent experiments. For both Zn and Se terminations, the interface Fe magnetic moments are higher than the bulk bcc Fe moment. We have also investigated the effect of adding Fe atoms on top of a reconstructed ZnSe surface to explore the role of reconstruction of semiconductor surfaces in determining properties of metal-semiconductor interfaces. Fe breaks the Se dimer bond formed for a Se-rich (2x1) reconstructed surface. Finally, we looked at the reverse growth i.e. growth of Zn and Se atoms on a bcc Fe(001) substrate to investigate the properties of the second interface of a magnetotunnel junction. The results are in good agreement with the theoretical and experimental results, wherever available.Comment: 7 pages, 8 figures, accepted for publication in PR

    The multifaceted role of serotonin in intestinal homeostasis

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    The monoamine serotonin, 5-hydroxytryptamine (5-HT), is a remarkable molecule with conserved production in prokaryotes and eukaryotes and a wide range of functions. In the gastrointestinal tract, enterochromaffin cells are the most important source for 5-HT production. Some intestinal bacterial species are also able to produce 5-HT. Besides its role as a neurotransmitter, 5-HT acts on immune cells to regulate their activation. Several lines of evidence indicate that intestinal 5-HT signaling is altered in patients with inflammatory bowel disease. In this review, we discuss the current knowledge on the production, secretion, and signaling of 5-HT in the intestine. We present an inventory of intestinal immune and epithelial cells that respond to 5-HT and describe the effects of these signaling processes on intestinal homeostasis. Further, we detail the mechanisms by which 5-HT could affect inflammatory bowel disease course and describe the effects of interventions that target intestinal 5-HT signaling
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