2,517 research outputs found

    Effect of matrix parameters on mesoporous matrix based quantum computation

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    We present a solid state implementation of quantum computation, which improves previously proposed optically driven schemes. Our proposal is based on vertical arrays of quantum dots embedded in a mesoporous material which can be fabricated with present technology. We study the feasibility of performing quantum computation with different mesoporous matrices. We analyse which matrix materials ensure that each individual stack of quantum dots can be considered isolated from the rest of the ensemble-a key requirement of our scheme. This requirement is satisfied for all matrix materials for feasible structure parameters and GaN/AlN based quantum dots. We also show that one dimensional ensembles substantially improve performances, even of CdSe/CdS based quantum dots

    Spin-based optical quantum gates via Pauli blocking in semiconductor quantum dots

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    We present a solid-state implementation of ultrafast conditional quantum gates. Our proposal for a quantum-computing device is based on the spin degrees of freedom of electrons confined in semiconductor quantum dots, thus benefiting from relatively long decoherence times. More specifically, combining Pauli blocking effects with properly tailored ultrafast laser pulses, we are able to obtain sub-picosecond spin-dependent switching of the Coulomb interaction, which is the essence of our conditional phase-gate proposal. This allows us to realize {\it a fast two qubit gate which does not translate into fast decoherence times} and paves the road for an all-optical spin-based quantum computer.Comment: 14 Pages RevTeX, 3 eps figures include

    May baseline JCV status influence the MS clinical evolution during Natalizumab treatment? Evidence from a multicenter-2 years-prospective study

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    Abstract Background We prospectively assessed the influence of JCV- status on disability's accrual in RRMS patients treated with Natalizumab at two tertiary MS centres, settled in Italy. Methods Negative binomial model was used to assess the influence of baseline JCV status (positive or negative) treatment on clinical and radiological disease activity during the 24 months' follow-up. Results One hundred eighty four patients treated with Natalizumab were enrolled (83 JCV +, whilst 101 JCV-). Over the two years of follow-up there was not significant clinical and radiological differences between the two groups. Conclusion JCV + RRMS did not showed a severe clinical course than JCV – RRMS

    Effects of weed control practices on plant diversity in a homogenous olive-dominated landscape (South-east of Italy)

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    Olive groves represent an important economic, agro-ecological, and cultural resource in the Mediterranean Basin. Weed management plays a fundamental role in their sustainable management. The aim of this work was to characterize and assess the plant diversity associated with different weed control practices, in a homogeneous olive-dominated landscape in the South-East of Italy. Sixty-five vegetation plots were sampled in orchards treated with different weed control practices: mowing, tillage, and use of chemical herbicides. The multi-response permutation procedure was used to test the hypothesis of no difference among the treatments. The relationships between plots were visualized by means of non-metric multidimensional scaling ordination. A generalized linear mixed model was used to analyze the relationships between weed control practices and life forms, chorotypes, and diversity indexes. The results showed that the three weed control practices determined slightly different plant communities. Chemically weeded orchards showed an impoverished floristic composition and the lowest diversity, whereas mowing and tillage yielded similar values. These latter two treatments differed for the percentages of hemicryptophytes and therophytes. Moreover, different from other studies, we did not find plant species of particular concern for biodiversity conservation. We hypothesize that this result is due to the monotonous structure of the agro-landscape we investigated, where natural elements are almost lacking. From this point of view, a correct management of agro-districts should consider both the agronomic practices at the level of the individual olive groves and the structure of the agro-landscape

    The SMILING project : prevention of falls by a mechatronic training device

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    Ageing is characterized by functional changes that can create gait and balance disturbances, which are the main risk factors of falling. Elderly people at risk of falling can be considered to be suffering from an involuntary motor behaviour that restricts their participation in society. One method to overcome such a situation is to activate a new learning process to train for real life tasks, which represents innovation. The SMILING system is intended to challenge the elderly to solve new problems in real time by inducing variable environments that need active response and problem solving. Variable environments induced by perturbations will weaken stiff motor behaviour(s), induce flexibility and thus enable effective training and improve mobility in real life environments. The SMILING solution provides a changeable yet safe environment that needs active response and problem solving by the user. It consists of a wearable non-invasive computer-controlled system that applies chaotic perturbations to the lower extremities during walking through small alterations of the height and slope of weight-bearing surfaces. The complete system consists of 3 modules: i) a complete walking analysis system; ii) a pair of motorised training shoes; iii) a user friendly portable control unit

    Probing molecular arrangements of the organic semiconductor 2,7-Dioctyl[1]benzothieno[3,2- b][1]benzothiophene thin film at the interface by UV Resonant Raman scattering

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    Raman spectroscopy was employed to investigate nanometric thick films of the organic semiconductor 2,7-Dioctyl[1]benzothieno[3,2-b][1]benzothiophene, following a comprehensive vibrational characterization of the compound condensed phases at various excitation wavelengths. UV Raman excitation enabled the characterization of the thin films, revealing that the molecular orientation at the film/air interface is characterized by a different organization and/or a high degree of disorder compared to the bulk phase. The low penetration depth of the UV Raman excitation allows for the retrieval of this information, unlike the XRD data

    Study of macular and optic disk blood flow by angio‐OCT in Glucose‐6‐Phosphate Dehydrogenase (G6PD) deficient men and age‐related G6PD‐normal subjects

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    Purpose: The reported prevalence of Glucose‐6‐Phosphate Dehydrogenase (G6PD) deficiency in Sardina, Italy, ranges from 8% to 15%. Hemizygous males have totally deficient erythrocytes. Evidence indicates that patients with G6PD deficiency are protected against ischemic heart and cerebrovascular disease, colorectal cancer, retinal vein occlusion, and nonarteritic anterior ischemic optic neuropathy. The purpose of this study was to study the macular and optic disk blood flow by angio‐OCT in G6PD‐deficient men and age‐related G6PD‐normal subjects and ascertain whether, or not, there are statistically significant differences between the two groups Methods: 22 G6PD‐deficient men and 22 perfectly age‐matched G6PD‐normal controls were examined at the Ophthalmology Unit, University of Sassari, Sassari, Italy. A complete review of the medical history and a complete ophthalmological examination, including ETDRS best corrected visual acuity, slit‐lamp biomicroscopy of the anterior segment, applanation tonometry, and fundus examination, was carried out. An HD 6‐mm Angio‐Retina and a 4.5‐mm Angio Disk (RT‐Vue, Optovue XR‐100 with Angio Vue, CA) examination were also performed Results: Only 1 eye per patients was included in the analysis, for a total of 22 eyes in each group. All the exported parameters about retinal and disk flow were evaluated. No statistical differences between the two groups were found, even after controlling for the effects of age, hypertension and hypercholesterolemia (p = 0.9). Conclusions: Results suggest that G6PD‐deficient and G6PD‐normal men have similar macular and optic disk blood flow. Larger scale studies are necessary to confirm these findings
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