23 research outputs found

    Paleobiology of titanosaurs: reproduction, development, histology, pneumaticity, locomotion and neuroanatomy from the South American fossil record

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    Fil: García, Rodolfo A.. Instituto de Investigación en Paleobiología y Geología. Museo Provincial Carlos Ameghino. Cipolletti; ArgentinaFil: Salgado, Leonardo. Instituto de Investigación en Paleobiología y Geología. General Roca. Río Negro; ArgentinaFil: Fernåndez, Mariela. Inibioma-Centro Regional Universitario Bariloche. Bariloche. Río Negro; ArgentinaFil: Cerda, Ignacio A.. Instituto de Investigación en Paleobiología y Geología. Museo Provincial Carlos Ameghino. Cipolletti; ArgentinaFil: Carabajal, Ariana Paulina. Museo Carmen Funes. Plaza Huincul. Neuquén; ArgentinaFil: Otero, Alejandro. Museo de La Plata. Universidad Nacional de La Plata; ArgentinaFil: Coria, Rodolfo A.. Instituto de Paleobiología y Geología. Universidad Nacional de Río Negro. Neuquén; ArgentinaFil: Fiorelli, Lucas E.. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica. Anillaco. La Rioja; Argentin

    Green Space and cognitive ageing: a retrospective life course analysis in the Lothian Birth Cohort 1936

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    International evidence suggests that green space has beneficial effects on general and mental health but little is known about how lifetime exposure to green space influences cognitive ageing. Employing a novel longitudinal life course approach, we examined the association between lifetime availability of public parks and cognitive ageing. Lifetime residential information was gathered from the participants of the Lothian Birth Cohort 1936 using a "life-grid" questionnaire at age 78 years. Parks information from 1949, 1969 and 2009 was used to determine a percentage of parks within a 1500 m buffer zone surrounding residence for childhood, adulthood, and later adulthood periods. Linear regressions were undertaken to test for association with age-standardised, residualised change in cognitive function (Moray House Test score) from age 11 to 70 years, and from age 70 to 76 (n = 281). The most appropriate model was selected using the results of a partial F-test, and then stratified by demographic, genetic and socioeconomic factors. The local provision of park space in childhood and adulthood were both important in explaining the change in cognitive function in later life. The association between childhood and adulthood park availability and change in the Moray House Test Score from age 70 to 76 was strongest for women, those without an APOE e4 allele (a genetic risk factor), and those in the lowest socioeconomic groups. Greater neighbourhood provision of public parks from childhood through to adulthood may help to slow down the rate of cognitive decline in later life, recognising that such environmental associations are always sensitive to individual characteristics

    Simulation of THz generation and propagation from photo-Dember emitters

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    We demonstrate a simulation of lateral photo-Dember terahertz (THz) emitters in two dimensions using the drift diffusion equation coupled to a finite-difference time-domain model with a far-field algorithm that can take into account the angular spectrum of emission and propagation. We show that the dynamics of the system are more dependent on the currents traveling perpendicular to the semiconductor surface, as opposed to just the lateral currents as previously thought. The 2D simulation is needed in order to correctly represent experiments that measure emission out of lateral photo-Dember emitters.</p

    Temperature dependent polarity inversion in double-metal terahertz emitters

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    The temperature dependent polarity inversion in double-metal THz emitters was investigated. Double-metal emitters utilising different metal pairings and single edge metal emitters were cooled in a helium flow cryostat and their THz emission was measured over a range of temperatures. Most emitters, including those with insulating layers between the metal and semiconductor, exhibit a flip in polarity of their THz emission between 50 and 100 K. This shows the inversion is a trait intrinsic to the semiconductor and not influenced by the metallic contact on the surface

    Double-metal Schottky enhanced THz emitters

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    Characterisation of THz emission from double-metal-patterned gallium-arsenide multiple emitters

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    Multiplexed gallium–arsenide (GaAs)-based terahertz (THz) emitters fabricated with periodic double-metal structures are demonstrated and the effect of different metals on the THz output is investigated. THz emission originates from the lateral photo-Dember effect and from the different Schottky barrier heights of the chosen metal pair. The metal combinations used were Au–Al, Au–Pb and Cu–Cr. The emitters were characterised according to temperature and the highest peak-to-peak THz emission was achieved with the Cu–Cr metal pairing at 150 K

    High temperature operation of integrated optical fiber

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    Integrated optical fiber is a planarized format, enabling ruggedized integrated functionality for silica optical fiber. This work is the first demonstration showing the platform's operation at temperatures exceeding 1000ÂșC.</p

    Leaky mode integrated optical fibre refractometer

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    A route to monitor external refractive indices greater than the core index of the waveguide is presented. Initial application utilizes an integrated optical fibre (IOF) platform due to its potential for use in harsh environment sensing. IOF is fabricated using a bespoke flame hydrolysis deposition process to fuse an optical fibre to a planar substrate achieving an optical quality, ruggedized glass layer between the fibre and substrate was fabricated. The presented refractometer is created by direct UV writing of multiple fibre Bragg gratings into an etched (22 ”m diameter) optical fibre post fabrication. Linear regression analysis is applied to quantify propagation loss by monitoring each FBG’s back reflected power. The device operates with a sensitivity of approximately 350 dB/cm/RIU at a refractive index of 1.451 at 1550 nm. Numerical simulations using a transfer matrix method are presented and potential routes for development are discussed.</p

    Fiber coupled acousto-optic modulators for near UV and blue wavelength applications

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    We present results from the development of a fiber-coupled Acousto-Optic modulator (Fiber-QÂź) operating at near-UV and blue wavelengths. A conventional TeO2 based Bragg diffraction design is introduced for short wavelengths optical input. Pure silica core single mode fibers (both Polarisation Maintaining (PM) and non-PM) are used as coupling fibers for their transmission at these wavelengths, and to avoid the possibility of photo darkening. The end of the fibers are fused with silica end-caps, lowering the power density on their fiber-air interfaces to achieve a higher power handling. The Fiber-QÂź can be optimized for multiple wavelengths (including 397nm or 422nm) and can accept power levels of up to 100mW. A hermetically sealed package is selected to provide a clean in-package environment thus protecting the optics from damage caused by external contamination. In this presentation we report details of the design, and test results of a fiber-coupled Acousto-Optic modulator that demonstrates the performance required for use in ion-trap quantum information processing applications.</p

    Survival outcome and predictors of gefitinib antitumor activity in East Asian chemonaive patients with advanced nonsmall cell lung cancer

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    BACKGROUND. Chemonaive patients had higher response rates than chemotherapy-treated patients in previous analyses of East Asian patients with advanced nonsmall cell lung cancer. The survival outcome and the predictors for antitumor activity in chemonaive patients who received gefitinib as first-line treatment are unclear. METHODS. Clinicopathologic predictive factors, objective tumor responses, and the survival of consecutive patients with advanced, chemonaive nonsmall cell lung cancer who received gefitinib as first-line treatment were collected and analyzed. Multivariate analysis was conducted to determine independent predictive factors for gefitinib antitumor efficacy. RESULTS. One hundred ninety-six patients (112 males and 84 females) were analyzed. Ninety-six patients (49%) were never smokers. One hundred forty-four patients (73%) had adenocarcinoma or bronchioloalveolar carcinoma histology. One hundred twenty patients had an Eastern Cooperative Oncology Group performance status 0 to 2. Eighty-three patients (42%; 95% confidence interval, 36-49%) had an objective tumor response. An additional 35 patients had stable disease (disease control rate, 61%). The tumor response rate was 52% in patients who had a good performance status. Female gender, nonsmoking status, and adenocarcinoma histology all were independent predictors of response or disease control in multivariate analysis. The median survival was 11.1 months, and the 1-year survival rate of patients who had a good performance status was 47.5%. CONCLUSIONS. The response rate to gefitinib was high in East Asian chemonaive patients with advanced nonsmall cell lung cancer. Female gender, adenocarcinoma histology, and nonsmoking status all were independent predictors of gefitinib response. The survival outcome of these patients was similar to that of patients who initially received chemotherapy. (c) 2006 American Cancer Society
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