719 research outputs found

    Retention of Text Material under Cued and Uncued Recall and Open and Closed Book Conditions

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    Evidence supports the benefits of effortful processing in strengthening retention of newly learned material. The present study compared two forms of effortful processing, uncued (free) recall and cued recall, under both open and closed book conditions, on both immediate and delayed (one-week) test performance. Participants read a section of a child psychology text and then completed either an uncued recall task in which they typed as much information as they could recall, or a cued recall task, in which they typed answers to study questions. Recall was conducted under open versus closed book conditions. No differences between cued and uncued conditions were obtained, but participants performed better on immediate test performance in the open book condition. No significant effects were found at delayed assessment. The results point to a short-term advantage of effortful review of text materials performed with access to study materials

    Automatic 3D facial model and texture reconstruction from range scans

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    This paper presents a fully automatic approach to fitting a generic facial model to detailed range scans of human faces to reconstruct 3D facial models and textures with no manual intervention (such as specifying landmarks). A Scaling Iterative Closest Points (SICP) algorithm is introduced to compute the optimal rigid registrations between the generic model and the range scans with different sizes. And then a new template-fitting method, formulated in an optmization framework of minimizing the physically based elastic energy derived from thin shells, faithfully reconstructs the surfaces and the textures from the range scans and yields dense point correspondences across the reconstructed facial models. Finally, we demonstrate a facial expression transfer method to clone facial expressions from the generic model onto the reconstructed facial models by using the deformation transfer technique

    Stress corrosion cracking in Al-Zn-Mg-Cu aluminum alloys in saline environments

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    Copyright 2013 ASM International. This paper was published in Metallurgical and Materials Transactions A, 44A(3), 1230 - 1253, and is made available as an electronic reprint with the permission of ASM International. One print or electronic copy may be made for personal use only. Systematic or multiple reproduction, distribution to multiple locations via electronic or other means, duplications of any material in this paper for a fee or for commercial purposes, or modification of the content of this paper are prohibited.Stress corrosion cracking of Al-Zn-Mg-Cu (AA7xxx) aluminum alloys exposed to saline environments at temperatures ranging from 293 K to 353 K (20 °C to 80 °C) has been reviewed with particular attention to the influences of alloy composition and temper, and bulk and local environmental conditions. Stress corrosion crack (SCC) growth rates at room temperature for peak- and over-aged tempers in saline environments are minimized for Al-Zn-Mg-Cu alloys containing less than ~8 wt pct Zn when Zn/Mg ratios are ranging from 2 to 3, excess magnesium levels are less than 1 wt pct, and copper content is either less than ~0.2 wt pct or ranging from 1.3 to 2 wt pct. A minimum chloride ion concentration of ~0.01 M is required for crack growth rates to exceed those in distilled water, which insures that the local solution pH in crack-tip regions can be maintained at less than 4. Crack growth rates in saline solution without other additions gradually increase with bulk chloride ion concentrations up to around 0.6 M NaCl, whereas in solutions with sufficiently low dichromate (or chromate), inhibitor additions are insensitive to the bulk chloride concentration and are typically at least double those observed without the additions. DCB specimens, fatigue pre-cracked in air before immersion in a saline environment, show an initial period with no detectible crack growth, followed by crack growth at the distilled water rate, and then transition to a higher crack growth rate typical of region 2 crack growth in the saline environment. Time spent in each stage depends on the type of pre-crack (“pop-in” vs fatigue), applied stress intensity factor, alloy chemistry, bulk environment, and, if applied, the external polarization. Apparent activation energies (E a) for SCC growth in Al-Zn-Mg-Cu alloys exposed to 0.6 M NaCl over the temperatures ranging from 293 K to 353 K (20 °C to 80 °C) for under-, peak-, and over-aged low-copper-containing alloys (~0.8 wt pct), they are typically ranging from 20 to 40 kJ/mol for under- and peak-aged alloys, and based on limited data, around 85 kJ/mol for over-aged tempers. This means that crack propagation in saline environments is most likely to occur by a hydrogen-related process for low-copper-containing Al-Zn-Mg-Cu alloys in under-, peak- and over-aged tempers, and for high-copper alloys in under- and peak-aged tempers. For over-aged high-copper-containing alloys, cracking is most probably under anodic dissolution control. Future stress corrosion studies should focus on understanding the factors that control crack initiation, and insuring that the next generation of higher performance Al-Zn-Mg-Cu alloys has similar longer crack initiation times and crack propagation rates to those of the incumbent alloys in an over-aged condition where crack rates are less than 1 mm/month at a high stress intensity factor

    Stability of gold nanowires at large Au-Au separations

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    The unusual structural stability of gold nanowires at large separations of gold atoms is explained from first-principles quantum mechanical calculations. We show that undetected light atoms, in particular hydrogen, stabilize the experimentally observed structures, which would be unstable in pure gold wires. The enhanced cohesion is due to the partial charge transfer from gold to the light atoms. This finding should resolve a long-standing controversy between theoretical predictions and experimental observations.Comment: 7 pages, 3 figure

    Magnetic pair breaking in disordered superconducting films

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    A theory for the effects of nonmagnetic disorder on the magnetic pair breaking rate α\alpha induced by paramagnetic impurities in quasi two-dimensional superconductors is presented. Within the framework of a strong-coupling theory for disordered superconductors, we find that the disorder dependence of α\alpha is determined by the disorder enhancements of both the electron-phonon coupling and the spin-flip scattering rate. These two effects have a tendency to cancel each other. With parameter values appropriate for Pb_{0.9} Bi_{0.1}, we find a pair breaking rate that is very weakly dependent on disorder for sheet resistances 0 < R < 2.5 kOhm, in agreement with a recent experiment by Chervenak and Valles.Comment: 6 pp., REVTeX, epsf, 2 eps figs, final version as publishe

    Effects of acanthoic acid on TNF-α gene expression and haptoglobin synthesis

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    Anti-inflammatory effects of Stephania tetrandra

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    Quasiparticle Inelastic Lifetime from Paramagnons in Disordered Superconductors

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    The paramagnon contribution to the quasiparticle inelastic scattering rate in disordered superconductors is presented. Using Anderson's exact eigenstate formalism, it is shown that the scattering rate is Stoner enhanced and is further enhanced by the disorder relative to the clean case in a manner similar to the disorder enhancement of the long-range Coulomb contribution. The results are discussed in connection with the possibility of conventional or unconventional superconductivity in the borocarbides. The results are compared to recent tunneling experiments on LuNi2_{2}B2_{2}C.Comment: 5 pages, no figure

    Minute ampullary carcinoid tumor with lymph node metastases: a case report and review of literature

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    <p>Abstract</p> <p>Background</p> <p>Carcinoid tumors are usually considered to have a low degree of malignancy and show slow progression. One of the factors indicating the malignancy of these tumors is their size, and small ampullary carcinoid tumors have been sometimes treated by endoscopic resection.</p> <p>Case presentation</p> <p>We report a case of a 63-year-old woman with a minute ampullary carcinoid tumor that was 7 mm in diameter, but was associated with 2 peripancreatic lymph node metastases. Mild elevation of liver enzymes was found at her regular medical check-up. Computed tomography (CT) revealed a markedly dilated common bile duct (CBD) and two enlarged peripancreatic lymph nodes. Endoscopy showed that the ampulla was slightly enlarged by a submucosal tumor. The biopsy specimen revealed tumor cells that showed monotonous proliferation suggestive of a carcinoid tumor. She underwent a pylorus-preserving whipple resection with lymph node dissection. The resected lesion was a small submucosal tumor (7 mm in diameter) at the ampulla, with metastasis to 2 peripancreatic lymph nodes, and it was diagnosed as a malignant carcinoid tumor.</p> <p>Conclusion</p> <p>Recently there have been some reports of endoscopic ampullectomy for small carcinoid tumors. However, this case suggests that attention should be paid to the possibility of lymph node metastases as well as that of regional infiltration of the tumor even for minute ampullary carcinoid tumors to provide the best chance for cure.</p
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