325 research outputs found

    Why metallic surfaces with grooves a few nanometers deep and wide may strongly absorb visible light

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    It is theoretically shown that nanometric silver lamellar gratings present very strong visible light absorption inside the grooves, leading to electric field intensities by several orders of magnitude larger than that of the impinging light. This effect, due to the excitation of long wave vector surface plasmon polaritons with particular small penetration depth in the metal, may explain the abnormal optical absorption observed a long time ago on almost flat Ag films. Surface enhanced Raman scattering in rough metallic films could also be due to the excitation of such plasmon polaritons in the grain boundaries or notches of the films.Comment: 5 pages, 5 figure, submitted to Phys. Rev. Let

    Efficient excitation of cavity resonances of subwavelength metallic gratings

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    One dimensional rectangular metallic gratings enable enhanced transmission of light for specific resonance frequencies. Two kinds of modes participating to enhanced transmission have already been demonstrated : (i) waveguide modes and (ii) surface plasmon polaritons (SPP). Since the original paper of Hessel and Oliner \cite{hessel} pointing out the existence of (i), no progress was made in their understanding. We present here a carefull analysis, and show that the coupling between the light and such resonances can be tremendously improved using an {\it evanescent} wave. This leads to enhanced localisation of light in cavities, yielding, in particular, to a very selective light transmission through these gratings.Comment: 4 pages, 5 figures, submitted to Phys. Rev. Let

    Anisotropic conductivity of silver thin films grown on silicon (100) vicinal surfaces

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    The electrical conductivity between 4 and 300 K of Ag thin films (up to 30 mm grown at room temperature on Si(100) vicinal surfaces has been measured and their morphology imaged with an atomic force microscope. A noticeable anisotropy of the resistivity of the films which is related to the structure of the films has been found)Laboratories du CNRS Departamento de Física Materia Condensada. Universidad Autónoma.Peer reviewe

    Surface shape resonances in lamellar metallic gratings

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    The specular reflectivity of lamellar gratings of gold with grooves 0.5 microns wide separated by a distance of 3.5 microns was measured on the 2000 cm1^{-1} - 7000 cm1^{-1} spectral range for p-polarized light. For the first time, experimental evidence of the excitation of electromagnetic surface shape resonances for optical frequencies is given. In these resonances the electric field is highly localized inside the grooves and is almost zero in all other regions. For grooves of depth equal to 0.6 microns, we have analyzed one of these modes whose wavelength (3.3 microns) is much greater than the lateral dimension of the grooves.Comment: 4 pages (LaTex), 5 postscript figures, to be published in Physical Review Letter

    Burden of respiratory disease attributable to secondhand smoke exposure at home in children in Spain (2015)

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    This study aimed to estimate the number of incident cases and hospital admissions attributable to secondhand smoke (SHS) exposure at home for asthma, otitis media (OM), and lower respiratory infections (LRI) in children in Spain. The burden of respiratory disease caused by SHS exposure was estimated in terms of incident cases and hospitalized cases for asthma, OM, and LRI. Estimates were calculated using the population attributable fraction. The age-specific (0-1 year, 0-4 years, 5-11 years, and 0-11 years) prevalence of SHS exposure in children was estimated through a telephone survey performed in a representative sample of Spanish households with children in 2016. The risk estimates for all diseases were selected from international meta-analyses. The number of hospitalized cases was obtained for each disease from the Hospital Minimum Data Set provided by the Ministry of Health of Spain. Incident cases were obtained from the Global Health Data Exchange. In 2015, SHS exposure caused an estimated total of 136,403 incident cases of the following respiratory diseases: 9058 (8.5%) cases of asthma, 120,248 (8.5%) of OM, and 7097 (13.5%) of LRI in children aged 0–14 years old in Spain. Likewise, SHS exposure caused a total of 3028 hospitalized cases, with 379 (8.5%) for asthma and 167 (8.5%) for OM in children 0–11 years old, and 2482 (11.6%) for LRI in children <2 years old. The high burden of respiratory disease attributed to SHS exposure supports the need to improve protection of children against SHS exposure by extending smoke-free regulations to homes and cars.This work was supported by the Instituto de Salud Carlos III (PN I+D+I 2013–2016) and co-funded by the European Regional Development Fund (FEDER) (grant number PI13/02734). The Evaluation and Intervention Methods Service of the Public Health Agency of Barcelona and the Tobacco Control Unit of the Catalan Institute of Oncology were also partially supported by the Ministry of Universities and Research of Catalonia (AGAUR) (grant numbers 2014SGR1373 and 2014SGR319). This project has received funding from the European Union's Horizon 2020 research and innovation program under grant agreement No 681040S

    Measurement of body composition in cancer patients using CT planning scan at the third lumbar vertebra

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    OBJECTIVE: the main objective was to assess body composition in terms of skeletal muscle index (SMI), myosteatosis, visceral adipose tissue (VAT), subcutaneous adipose tissue (SAT), and intermuscular adipose tissue (IMAT) as an adjunct of information provided by radiotherapy CT planning scan. MATERIAL AND METHODS: a sample of 49 patients with lung and digestive cancers underwent a CT scan for radiotherapy treatment, which included measurements at the L3 region. Images were analyzed with a radiotherapy contouring software, using different Hounsfield Unit (HU) settings. Cross-sectional areas (cm2) were automatically computed by summing tissue pixels and multiplying by pixel surface area. Low SMI (cm2/m2) and muscle density (HU) were determined according to the recently established cut-off points. RESULTS: the prevalence of low SMI was detected in 46.94% of patients, being present in 8 women, 4 men with BMI < 25 kg/m2, and 11 men with BMI ≥ 25 kg/m2. The average mean skeletal attenuation of total skeletal muscle area was 29.02 (± 8.66) HU, and myosteatosis was present in 13 women (81.25%) and 31 men (93.94%). Mean SAT was 131.92 (± 76.80) cm2, mean VAT was 133.19 (± 85.28) cm2, and mean IMAT was 11.29 (± 12.86) cm2. CONCLUSION: skeletal muscle abnormalities are frequently present in cancer patients and a low SMI may also exist even in the presence of overweight. As CT scans are an important tool at any radiation oncology department, they could also be used to offer highly sensitive and specific information about body composition, as well as to detect early malnutrition before starting radiotherapy treatment

    Iniltration vs. instillation of ropivacaine 7.5% in radical mastectomies for postoperative analgesia

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    Objective: Determining the effectiveness of iniltration versus instillation with 7.5% ropivacaine in reducing the intensity of postoperative pain in patients undergoing a radical mastectomy. Material and methods: Clinical, prospective, and comparative analytical study in a sample of 20 female patients between 20 and 60 years of age, ASA I and II, weight 50-90 kg, who were divided into 2 groups (10 patients each). In Group 1 infiltration with ropivacaine 7.5% (20 ml) was applied prior to closure of the surgical wound, meanwhile in Group 2 ropivacaine 7.5% (20 ml), was instilled into the surgical wound. P ain intensity was assessed by a visual analog scale (V AS) upon extubation. The need for rescue medication and the incidence of nausea and vomiting were measured from 0 to 30 minutes postoperatively and at 2, 4, 8 and 12 hours. Results: There was no statistical difference between the groups (only the group managed through iniltration required rescue medications), but the iniltration group had a lower perception of pain. Conclusions: This study reported the same eficacy of preventive treatment of postoperative pain in patients who underwent radical mastectomy for instillation and iniltration with 7.5% ropivacaine and little need for rescue medication postoperatively

    Adultery and the Rumor Mill: les bourgeois de Molinchart and El gran galeoto

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    This article seeks to challenge interpretations of the adultery plot as a subversive current in nineteenth-century literature by examining two texts that are often dismissed by contemporary critics: Les bourgeois de Molinchart (1854), a novel by the French writer Champfleury (the pseudonym of Jules Husson), and El gran Galeoto (1881), a play by the Spanish playwright Jos, Echegaray. In each of these works, the rumor of the adultery precedes and to a large extent precipitates the infidelity at the end of the work. In committing adultery, therefore, the protagonists are not rising up against social norms so much as capitulating to the expectations of society, enacting a plot that has been projected upon them. The essay compares and contrasts the treatment of the rumor mill in the two works and examines the literary strategies that the writers use to undercut a transgressive reading of the infidelity plot
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