112,432 research outputs found

    Sensitivity-based investigation of threshold voltage variability in 32-nm flash memory cells

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    We investigate variability of a 32 nm flash memory cell and of 32 nm MOSFETs with a methodology based on sensitivity analysis performed with a limited number of TCAD simulations. We show that – as far as the standard deviation of the threshold voltage is concerned – our method provides results in very good agreement with those from three-dimensional atomistic statistical simulations, with a computational burden that is orders of magnitude smaller. We show that the proposed approach is a powerful tool to understand the role of the main variability sources and to explore the device design parameter space

    Surgical management of retinal detachment because of macular hole in highly myopic eyes

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    PURPOSE: The purpose of this study was to review the current management of macular hole retinal detachment in highly myopic eyes. METHODS: We searched English MEDLINE databases from January 1997 to January 2011 for surgical management of macular hole retinal detachment in highly myopic eyes. The main outcomes reported include retinal reattachment and visual acuity after primary surgery. RESULTS: Surgical procedures including pneumoretinopexy, pars plana vitrectomy with gas or silicone oil tamponade with or without laser therapy around the macular hole, and macular buckling have been the primary treatment choices. New techniques, including internal limiting membrane or epiretinal membrane peeling and heavy silicone oil tamponade, have been introduced over the last decade, and use of optical coherence tomography has allowed evaluation of the postoperative anatomical status of holes undetectable by conventional ophthalmoscope or lens biomicroscope. Poor functional and anatomical outcomes and nonclosure or reopening of a macular hole are still crucial problems, and some patients may require multiple procedures. CONCLUSION: Macular hole retinal detachment in highly myopic eyes is one of the most difficult types of retinal detachment to treat, and its primary treatment choice is still controversial, although the different surgical techniques reported in this review have been demonstrated as good surgical options. Randomized clinical trials are largely lacking. © Lippincott Williams & Wilkins

    Influence of motion on face recognition

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    The influence of motion information and temporal associations on recognition of non-familiar faces was investigated using two groups which performed a face recognition task. One group was presented with regular temporal sequences of face views designed to produce the impression of motion of the face rotating in depth, the other group with random sequences of the same views. In one condition, participants viewed the sequences of the views in rapid succession with a negligible interstimulus interval (ISI). This condition was characterized by three different presentation times. In another condition, participants were presented a sequence with a 1-sec. ISI among the views. That regular sequences of views with a negligible ISI and a shorter presentation time were hypothesized to give rise to better recognition, related to a stronger impression of face rotation. Analysis of data from 45 participants showed a shorter presentation time was associated with significantly better accuracy on the recognition task; however, differences between performances associated with regular and random sequences were not significant

    Transconjunctival sutureless 25-gauge versus 20-gauge standard vitrectomy: Correlation between corneal topography and ultrasound biomicroscopy measurements of sclerotomy sites

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    Purpose: To determine the correlation between corneal shape changes and ultrasound biomicroscopy (UBM) findings at the sclerotomy sites in conventional 20-gauge (G) pars plana vitrectomy (PPV) and 25-G transconjunctival sutureless vitrectomy (TSV) and to compare the effectiveness of the two surgical methods. Design: Prospective, comparative, observational case series. Methods: Sixty consecutive eyes (60 patients) undergoing primary 3-port PPV. Thirty eyes (30 patients, group 20-G) were treated with 20-G standard PPV and 30 eyes (30 patients, group 25-G) with 25-G TSV. We compared healing of the sclerotomy sites in the two groups. We determined the correlation between corneal shape changes (surgically induced astigmatism) measured by videokeratography and the durations of scleral healing cicatrization by UBM within each group. Results: UBM examination showed that the 20-G sclerotomy sites took about 8 weeks to heal, measured as complete opposition, whereas healing of the 25-G TSV sclerotomy was quite rapid, with complete scleral opposition in about 4 weeks. Corneal topography analysis showed, during the early postoperative period, a surgically induced steepening of the cornea in both groups (20 G, 3.08 ± 0.56 diopters and 25 G, 0.805 ± 0.61 diopters, P < 0.001, Mann-Whitney test), which then decreased gradually, recovering to the preoperative level within two months in group 20 G (P > 0.05) and 1 month in group 25 G (P > 0.05). We found a strong statistical correlation between the mean surgically induced keratometric astigmatism and the mean UBM measures of scleral healing (r = 0.99 for group 20 G and r = 0.97 for group 25 G). Conclusion: After PPV, astigmatic changes are especially significant in the early postoperative period in 20-G group; the 25-G TSV system results in faster reduction of surgically induced keratometric astigmatism because of rapid cicatrization of the sclerotomy sites. © 2009 by Lippincott Williams & Wilkins
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