4,495 research outputs found
Important Prospect: Workshop on Botanical Research and Management in Galàpagos, to be Held at the Charles Darwin Research Station, Santa Cruz, Galàpagos, Ecuador, 12-18 April 1987
UV Photosensing Characteristics of Nanowire-Based GaN/AlN Superlattices
We have characterized the photodetection capabilities of single GaN nanowires
incorporating 20 periods of AlN/GaN:Ge axial heterostructures enveloped in an
AlN shell. Transmission electron microscopy confirms the absence of an
additional GaN shell around the heterostructures. In the absence of a surface
conduction channel, the incorporation of the heterostructure leads to a
decrease of the dark current and an increase of the photosensitivity. A
significant dispersion in the magnitude of dark currents for different single
nanowires is attributed to the coalescence of nanowires with displaced
nanodisks, reducing the effective length of the heterostructure. A larger
number of active nanodisks and AlN barriers in the current path results in
lower dark current and higher photosensitivity, and improves the sensitivity of
the nanowire to variations in the illumination intensity (improved linearity).
Additionally, we observe a persistence of the photocurrent, which is attributed
to a change of the resistance of the overall structure, particularly the GaN
stem and cap sections. In consequence, the time response is rather independent
of the dark current.Comment: This document is the unedited Author's version of a Submitted Work
that was subsequently accepted for publication in Nano Letters (2016),
copyright (C) American Chemical Society after peer review. To access the
final edited and published work see
http://dx.doi.org/10.1021/acs.nanolett.6b0080
Age effect on retina and optic disc normal values
Purpose:
To investigate retinal thickness and optic disc parameters by the Retinal Thickness Analyzer (RTA) glaucoma program in older normal subjects and to determine any age effect.
Methods:
Subjects over 40 years of age without any prior history of eye diseases were recruited. Only subjects completely normal on clinical ophthalmologic examination and on visual field testing by Humphrey Field Analyzer (HFA) using the SITA 24-2 program were included. A total of 74 eyes from 74 subjects with even age distribution over the decades were enrolled and underwent topographic measurements of the posterior pole and of the optic disc by RTA. The `glaucoma full' program in software version 4.11B was applied.
Results:
Mean patient age was 59.9 +/- 10.3 years with a range from 40 to 80 years. The only parameter intraocular pressure (IOP) correlated with was retinal posterior pole asymmetry (r=0.27, p=0.02). IOP itself increased significantly with age (r=0.341, p=0.003). Mean defect and pattern standard deviation of the HFA did not correlate with any of the retinal or optic disc measurements. Increasing age correlated significantly with some of the morphologic measurements of the RTA: decreasing perifoveal minimum thickness (r=-0.258, p=0.026), increased cup-to-disc area ratio (r=0.302, p=0.016) and increased cup area (r=0.338 p=0.007).
Conclusions:
An age effect exists for some of the retina and optic disc measurements obtained by the RTA. Copyright (C) 2005 S. Karger AG, Basel
Rumbo a una economía de datos masivos y su relación con la economía y la sociedad de la información en los territorios fronterizos y periféricos
[ES] El taller sobre Tecnologías Disruptivas de la Información y la Comunicación para la Innovación y la Transformación Digital, organizado en el ámbito del proyecto DISRUPTIVE (disruptive.usal.es) y celebrado el 12 de septiembre de 2022 en Valladolid, tiene como objetivo debatir sobre los problemas, retos y beneficios del uso de tecnologías digitales disruptivas, a saber, Internet de las Cosas, Big data, computación en la nube, sistemas multiagente, aprendizaje automático, realidad virtual y aumentada y robótica colaborativa, para apoyar la transformación digital en curso en la sociedad.
El programa del taller incluyó 6 papers técnicos aceptados, 2 charlas de invitados y una sesión de networking. Este volumen contiene 6 de las ponencias presentadas en el taller sobre Tecnologías Disruptivas de la Información y la Comunicación para la Innovación y la Transformación Digital.
Este taller fue organizado por ICE (Instituto para la Competitividad Empresarial de Castilla y León), UVa (Universidad de Valladolid) y apoyado principalmente por el Fondo Europeo de Desarrollo Regional (FEDER) a través del Programa Interreg España-Portugal V-A (POCTEP) bajo la subvención 0677_DISRUPTIVE_2_E (Dinamización de los Digital Innovation Hubs dentro de la región PocTep para el impulso de las TIC disruptivas y de última generación a través de la cooperación en la región transfronteriza).[EN] The workshop on Disruptive Information and Communication Technologies for Innovation and Digital transformation, organized under the scope of the DISRUPTIVE project (disruptive.usal.es) and held on September 12, 2022 in Valladolid, aims to discuss problems, challenges and benefits of using disruptive digital technologies, namely Internet of Things, Big data, cloud computing, multi-agent systems, machine learning, virtual and augmented reality, and collaborative robotics, to support the on-going digital transformation in society.
The main topics included: Intelligent Manufacturing Systems; Industry 4.0 and digital transformation; Internet of Things; Cyber-security; Collaborative and intelligent robotics; Multi-Agent Systems; Industrial Cyber-Physical Systems; Virtualization and digital twins; Predictive maintenance; Virtual and augmented reality, Big Data and advanced data analytics; Edge and cloud Computing; Digital Transformation.
The workshop program included 6 accepted technical papers, 2 invited talks and a networking session. This volume contains 6 of the papers presented at the Workshop on Disruptive Information and Communication Technologies for Innovation and Digital Transformation.
This workshop was organized by ICE (Institute for Business Competitiveness of Castilla y León), UVa (University of Valladolid) and mainly supported by the European Regional Development Fund (ERDF) through the Interreg Spain-Portugal V-A Program (POCTEP) under grant 0677_DISRUPTIVE_2_E (Intensifying the activity of Digital Innovation Hubs within the PocTep region to boost the development of disruptive and last generation ICTs through cross-border cooperation)
Galactic Magnetic Turbulence from Radio data
Fluctuations in the Galactic synchrotron emission can be traced by the
angular power spectrum of radio maps at low multipoles. At frequencies below
few GHz, large-scale anisotropies are mainly induced by magnetic field
turbulence. By performing an analysis of five radio maps, we extract
constraints on turbulence spectral index and halo scale. Results favour a power
spectrum significantly flatter than for 3D Kolmogorov-like turbulence, and a
thin halo. This can be interpreted as an indication supporting non-conventional
models of propagation of cosmic-ray particles in the Galaxy, or as a suggestion
of a spectral-index break in the observed magnetic turbulence power spectrum.Comment: 15 pages, 3 figures. v2: discussions and references improved, to
appear in Astropart.Phys.
Stretching and contraction of extensional basins with pre-rift salt: a numerical modelling approach
We present a series of 2D thermo-mechanical numerical experiments of thick-skinned crustal extension including a pre-rift salt horizon and subsequent thin-, thick-skinned, or mixed styles of convergence accompanied by surface processes. Extension localization along steep basement faults produces half-graben structures and leads to variations in the original distribution of pre-rift salt. Thick-skinned extension rate and salt rheology control hanging wall accommodation space as well as the locus and timing of minibasin grounding. Upon shortening, extension-related basement steps hinder forward propagation of evolving shallow thrust systems; conversely, if full basin inversion takes place along every individual fault, the regional salt layer is placed back to its pre-extensional configuration, constituting a regionally continuous décollement. Continued shortening and basement involvement deform the shallow fold-thrust structures and locally breaches the shallow décollement. We aim at obtaining a series of structural, stratigraphic and kinematic templates of fold-and-thrust belts involving rift basins with an intervening pre-rift salt horizon. Numerical results are compared to natural cases of salt-related inversion tectonics to better understand their structural evolution
Exploring benthic diatom diversity in the West Antarctic Peninsula: insights from a morphological and molecular approach
Polar regions are among the most extreme habitats on Earth. However, diatom biodiversity in those regions is much more extensive and ecologically diverse than previously thought. The objective of this study was to add knowledge to benthic diatom biodiversity in Western Antarctic coastal zones via identification by means of morphology, DNA metabarcoding and cultured isolates. In addition, a taxonomically validated reference library for Antarctic benthic diatoms was established with comprehensive information on habitat, morphology and DNA barcodes (rbcL and 18SV4). Benthic samples from marine, brackish and freshwater habitats were taken at the Antarctic Peninsula. A total of 162 clonal cultures were established, resulting in the identification of 60 taxa. The combination of total morphological richness of 174 taxa, including the clones, with an additional 73 taxa just assigned by metabarcoding resulted in 247 infrageneric taxa. Of those taxa, 33 were retrieved by all three methods and 111 only by morphology. The barcode reference library of Antarctic species with the new references obtained through culturing allowed the assignment of 47 taxa in the metabarcoding analyses, which would have been left unassigned because no matching reference sequences were available before. Non–metric multidimensional scaling analyses of morphological as well as molecular data showed a clear separation of diatom communities according to water and substratum types. Many species, especially marine taxa, still have no record in reference databases. This highlights the need for a more comprehensive reference library to further improve routine diatom metabarcoding. Overall, a combination of morphological and molecular methods, along with culturing, provides complementary information on the biodiversity of benthic diatoms in the region
International lease accounting reform and economic consequences: the views of UK users and preparers
In response to perceived difficulties with extant lease-accounting standards in operation worldwide, the G4+1 issued a discussion paper which proposes that all leases should be recognized on the balance sheet [ASB (1999). Leases: Implementation of a new approach, discussion paper. London: Accounting Standards Board]. Leasing is now on the active agenda of the IASB. A major difficulty faced by standard setters lies in overcoming the preparer/user lobbying imbalance and obtaining ex ante evidence on the likely impact of regulatory reform. This paper contributes to the ongoing international debate by conducting a questionnaire survey of U.K. users and preparers to assess their views on proposals for lease-accounting reform and on the potential economic consequences of their adoption. The results, based on 132 responses, indicate that both groups accept that there are deficiencies in the current rules, but they do not agree on the way forward and believe that the proposals would lead to significant economic consequences for key parties. The impact on respondents' views of familiarity with the proposals, level of lease usage, and company size, is also examined
Enfoque de juventudes en la gestión pública : bases para su transversalización
El objetivo del documento es que sea utilizado por tomadores de decisiones públicas, funcionarios, especialistas y profesionales en el diseño e implementación de políticas, programas e iniciativas públicas. De esta manera, las acciones estatales podrán contar con los componentes pertinentes para que respondan e incorporen a las expectativas, preocupaciones, necesidades y experiencias de la población joven con el fin de garantizar el ejercicio de sus derechos y su participación en el desarrollo del país. En lo que sigue, las secciones segunda y tercera del presente documento enmarcan, reflexionan y definen el enfoque de juventudes. La sección cuarta propone acciones para adoptar el enfoque de juventudes en instituciones públicas. La sección quinta ofrece instrumentos para dotar del enfoque de juventudes a iniciativas públicas (planes, programas y proyectos). Todo ello responde a la necesidad, por parte de las acciones estatales, de identificar las características de las y los ciudadanos a los que se dirigen según su etapa de vida y se construyan relaciones más justas y dialogantes entre personas pertenecientes a diferentes generaciones. Se trata, en suma, de avanzar hacia una gestión pública efectivamente atenta a aquello que las juventudes requieren para alcanzar su bienestar y desarrollo integral, reconociéndolas como agentes fundamentales del cambio social, el desarrollo económico, humano e inclusivo y la innovación social y tecnológica
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