2,372 research outputs found

    Far infrared giant dipole resonances in neutral quantum dots

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    A resonance behaviour of the far infrared absorption probability at a frequency \sim N^{1/4} is predicted for clusters of N electron-hole pairs (2\le N\le 110) confined in disk-shaped quantum dots. For radially symmetric dots, the absorption is dominated by a Giant Dipole Resonance, which accounts for more than 98 % of the energy-weighted photoabsorption sum rule.Comment: final versio

    Managing Patient Expectations with Implant Treatment

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    This patient came to University of the Pacific, Arthur A. Dugoni School of Dentistry to get implants and implant crowns to improve his smile, replacing his upper partial denture. Different approaches were made by the faculty to arrive at best outcomes, which took four years for the patient to receive the treatment he wanted. This abstract will further detail how the treatment was conducted and the results afterwards

    Barred-beach morphological control on infragravity motion

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    A conceptual analysis of the coupling between bars and infragravity waves is performed combining laboratory experiments and numerical modeling. Experiments are carried out in a wave flume with a barred profile. The Boussinesq fully-nonlinear model SERR1D is validated with the laboratory data and a sensitivity analysis is performed next to study the influence on the infragravity wave dynamics of bar amplitude and location, and swash zone slope. A novel technique of incident and reflected motions separation that conserves temporal characteristics is applied. We observe that changing bar characteristics induces substantial variations in trapped energy. Interestingly, a modification of swash zone slope has a large influence on the reflected component, controlling amplitude and phase time-lag, and consequently on the resonant pattern. Variations of trapped infragravity energy induced by changes of swash zone slope reach 25 %. These changes in infragravity pattern consequently affect short-wave dynamics by modifying the breakpoint location and the breaking intensity. Our conceptual investigation suggests the existence of a morphological feedback through the action of evolving morphology on infragravity structures which modulates the action of short-waves on the morphology itself

    Dural Arteriovenous Malformations: A Review of the Literature and a Presentation of the JHN Series

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    Dural arteriovenous malformations (DAVMs), also known as dural arteriovenous fistulas, are arteriovenous shunts from a dural arterial supply to a dural venous channel, typically supplied by pachymeningeal arteries and located near a major venous sinus.1 The etiology of these lesions is not fully understood. DAVMs in the pediatric population are associated with structural venous abnormalities ,2 but the majority of DAVMs are thought to be acquired. Different etiologies have been implicated in this phenomenon, namely: sinus thrombosis, trauma or surgery.2–

    Social Inclusion: The Higher Education Sector in Chile and in the United Kingdom

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    The Higher Education (HE) systems of Chile and the UK are compared in terms of the ‘massification’ (Altbach, 1989) and the relevance and adequacy of the private-public provision mix. Dissimilar, each country has tried to build social inclusion into HE outreach at the same time as allowing participation of the private sector. Also included in the research are a) the role of social capital as a positive contribution for the social and economic development; b) the current state of social inequality in access to HE; and c) an in-depth analysis of the implications of both state and private roles over social inclusion in HE. Outreach programmes from each country, the Propedeutico in Chile and Aimhigher in the UK, are also analysed for lessons learned

    Use of non-intrusive laser exfoliation to improve substance uptake into citrus leaves [version 2; peer review: 2 approved]

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    Background: Despite the presence of stomata in leaves, foliar application of agrochemicals can be extremely inefficient due to the low permeability of leaf cuticular surfaces to polar compounds. Methods: This study introduced a laser-based “wax exfoliation” method to facilitate the penetration of substances into the leaf and, together with enhancing their uptake into the phloem and subsequent transport across tissue. This investigation demonstrated the effectiveness and non-invasive properties of laser exfoliation to improve the penetration of foliar-applied substances into citrus leaves. Results: This work presents the use of laser energy to exfoliate the cuticle of a leaf, with the highest energy density of 0.76 J/ cm2 resulting in 85-90% exfoliation across the entire laser-spot area. The infrared wavelength of the erbium laser is specifically chosen to target the wax cuticle without causing damage to the underlying epidermal cells. This selective ablation allows for increased penetration of therapeutic compounds into the leaf and transportation throughout the plant's vasculature. This is demonstrated using a fluorescent glucose analog applied to the laser treated leaves, showing increased penetration and transport throughout the leaf. Conclusions: Our findings demonstrate that the use of laser technology for the foliar application of agrochemicals provides significant advantages, including improved foliage uptake of therapeutic compounds. The method of cuticle exfoliation presented in this study is highly effective and non-intrusive, limiting its effects to the cuticle only. Future work should focus on the development of prototypes for in-field applications, including testing at longer distances as the Er:YAG laser does not require a lens for this application

    WFPC2 Observations of the Hubble Deep Field-South

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    The Hubble Deep Field-South observations targeted a high-galactic-latitude field near QSO J2233-606. We present WFPC2 observations of the field in four wide bandpasses centered at roughly 300, 450, 606, and 814 nm. Observations, data reduction procedures, and noise properties of the final images are discussed in detail. A catalog of sources is presented, and the number counts and color distributions of the galaxies are compared to a new catalog of the HDF-N that has been constructed in an identical manner. The two fields are qualitatively similar, with the galaxy number counts for the two fields agreeing to within 20%. The HDF-S has more candidate Lyman-break galaxies at z > 2 than the HDF-N. The star-formation rate per unit volume computed from the HDF-S, based on the UV luminosity of high-redshift candidates, is a factor of 1.9 higher than from the HDF-N at z ~ 2.7, and a factor of 1.3 higher at z ~ 4.Comment: 93 pages, 25 figures; contains very long table
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