2,231 research outputs found
Local government debt: an application to the Spanish case
For the last years, Europe has been subject to fiscal austerity in order to satisfy the Maastrich criteria. In this way, Spanish municipalities have been affected by new regulations and local government structure has changed. This paper is focused on the main factors that explain local government debt. In particular, budgetary information of a group of Spanish municipalities is used (1990-2000). Econometric analysis of cross section and panel data are presented. Key words:Fiscal Federalism, Local Government, debt, decentralization.
Polarized Plasmonic Enhancement by Au Nanostructures Probed through Raman Scattering of Suspended Graphene
We characterize plasmonic enhancement in a hotspot between two Au nanodisks
using Raman scattering of graphene. Single layer graphene is suspended across
the dimer cavity and provides an ideal two-dimensional test material for the
local near-field distribution. We detect a Raman enhancement of the order of
103 originating from the cavity. Spatially resolved Raman measurements reveal
a near-field localization one order of magnitude smaller than the wavelength
of the excitation, which can be turned off by rotating the polarization of the
excitation. The suspended graphene is under tensile strain. The resulting
phonon mode softening allows for a clear identification of the enhanced signal
compared to unperturbed graphene
DETECCCIÓN DE ANTICUERPOS SEROLÓGICOS CONTRA Chlamydophila abortus EN DOS GRUPOS DE PERSONAS EXPUESTAS A RIESGO EN EXPLOTACIONES OVINAS EN XALATLACO, MÉXICO
Chlamydophila abortus ( Cp. abortus ) es una bacteria causante del Aborto Enzoótico Ovino; la importancia zoonótica de Cp. abortus ocurre durante el manejo de animales enfermos. El presente trabajo estima la prevalencia de personas con anticuerpos contra Cp. abortus en grupos de riesgo laboral expuestos y los posibles factores de riesgo. Se condujo un estudio trasversal en d os grupos de personas expuestas. En el grupo A se incluyeron a 86 propietarios de rebaños y trabajadores. El grupo B por 52 profesionales de Medicina Veterinaria. Los títulos de anticuerpos se determinaron mediante ELISAr y se aplicó un cuestionario a los participantes para establecer los factores de riesgo. La prevalencia de anticuerpos contra Cp. abortus en productores y profesionistas fue de 6.52% (IC 95% 3.02 - 12.01%). Por grupo de riesgo la prevalencia en productores fue de 4.45% (IC 95% 1.28 11.48) y en profesionistas 9.62% (IC 95% 3.19 21.02), en mujeres 5.07% (IC 95% 1.99 11.29) y 1.44% en hombres; sin mostrar diferencias (P > 0.05). Se concluye que la prevalencia de anticuerpos frente a Cp. abortus en profesionistas y productores de ovinos es baja y los factores de riesgo no mostraron diferencias significativas
Analysis of the recording of Fibonacci lenses using photopolymers with 3-D diffusion model
In the present work, a 3-Dimensional diffusion model is proposed to predict the main properties of Diffractive Optical Elements (DOEs), recorded in photopolymers, including refractive index modulation and the evolution of the transverse intensity distribution. The model enables the selection of appropriate material characteristics based on the intended application of the DOE. Specifically, a PVA/AA photopolymer based on acrylamide is simulated using the proposed model, considering coverplating and index matching systems to mitigate the effects of thickness variation. In order to compare its properties using the suggested model, the simulation focuses on a Fibonacci Lens and the dependece of the intensity on the polymerization rate. Accordingly, axial intensity pattern is represented to prove the bifocal-behaviour of these diffractive lenses.Funded by the “Generalitat Valenciana” (Spain) (ID- IFEDER/2021/014, cofunded by EU through FEDER Pro- gramme; PROMETEO/2021/006 and INVEST/2022/419 financed by Next Generation EU), “Ministerio de Ciencia e Innovación” (Spain) (PID2021-123124OB-I00)
Toxic metals in toenails as biomarkers of exposure: A review
Toenails have been used as biomarkers of exposure to toxic metals, but their validity for this purpose is not yet clear and might differ depending on the specific agent. To evaluate this issue, we reviewed the literature on: a) the time-window of exposure reflected by toenails; b) the reproducibility of toenail toxic-metal levels in repeated measures over time; c) their relationship with other biomarkers of exposure, and; d) their association with potential determinants (i.e. sociodemographic, anthropometric, or lifestyle characteristics) or with sources of exposure like diet or environmental pollution. Thus, we performed a systematic review, searching for articles that provided original data for levels of any of the following toxic metals in toenails: aluminum, beryllium, cadmium, chromium, mercury, nickel, lead, thallium and uranium. We identified 88 articles, reporting data from 67 different research projects, which were quite heterogeneous with regard to population profile, sample size and analytical technique. The most commonly studied metal was mercury. Concerning the time-window of exposure explored by toenails, some reports indicate that toenail cadmium, nickel and lead may reflect exposures that occurred 7-12 months before sampling. For repeated samples obtained 1-6 years apart, the range of intraindividual correlation coefficients of aluminum, chromium and mercury was 0.33-0.56. The correlation of toxic metal concentrations between toenails and other matrices was higher for hair and fingernails than for urine or blood. Mercury levels were consistently associated with fish intake, while other toxic metals were occasionally associated with specific sources (e.g. drinking water, place of residence, environmental pollution, and occupation). The most frequently evaluated health endpoints were cardiovascular diseases, cancer, and central nervous system diseases. Available data suggest that toenail mercury levels reflected long-term exposures and showed positive associations with fish intake. The lack of standardization in sample collection, quality control, analytical techniques and procedures - along with the heterogeneity and conflicting results among studies - mean it is still difficult to conclude that toenails are a good biomarker of exposure to toxic metals. Further studies are needed to draw solid conclusions about the suitability of toenails as biomarkers of exposure to toxic metals.This work was supported by FIS grants PI12/00150, PI17CIII/00034, PI18/00287 (Instituto de Salud Carlos III, State Secretary of R + D + I and European Union (ERDF/ESF, “Investing in your future")), P42ES010349 and P30ES009089 (National Institute of Environmental Health Sciences).S
Occurrence and identification of microplastics along a beach in the Biosphere Reserve of Lanzarote
This work studied the accumulation of plastic debris in a remote beach located in La Graciosa island (Chinijo archipelago, Canary Islands). Microplastics were sampled in the 1&#-5&;8239#mm mesh opening range. An average plastic density of 36.3 g/m2 was obtained with a large variability along the 90 m of the beach (from 8.5 g/m2 to 103.4 g/m2). Microplastic particles preferentially accumulated in the part of the beach protected by rocks. A total number of 9149 plastic particles were collected, recorded and measured, 87% of which corresponded to fragments. Clear colours and microscopic evidence of weathering corresponded to aged plastics wind-driven by the surface Canary Current. The chemical composition of plastics particles corresponded to PE (63%), PP (32%) and PS (3%). Higher PE/PP ratios were recorded in the more protected parts of the beach, suggesting preferential accumulation of more aged fragments
Mutation study of Spanish patients with Hereditary Hemorrhagic Telangiectasia
<p>Abstract</p> <p>Background</p> <p>Hereditary Hemorrhagic Telangiectasia (HHT) is an autosomal dominant and age-dependent vascular disorder characterised mainly by mutations in the Endoglin (ENG) or activin receptor-like kinase-1 (ALK1, ACVRL1) genes.</p> <p>Methods</p> <p>Here, we have identified 22 ALK1 mutations and 15 ENG mutations, many of which had not previously been reported, in independent Spanish families afflicted with HHT.</p> <p>Results</p> <p>We identified mutations in thirty-seven unrelated families. A detailed analysis of clinical symptoms was recorded for each patient analyzed, with a higher significant presence of pulmonary arteriovenous malformations (PAVM) in HHT1 patients over HHT2. Twenty-two mutations in ALK1 and fifteen in ENG genes were identified. Many of them, almost half, represented new mutations in ALK1 and in ENG. Missense mutations in ENG and ALK1 were localized in a tridimensional protein structure model.</p> <p>Conclusion</p> <p>Overall, ALK1 mutations (HHT2) were predominant over ENG mutations (HHT1) in our Spanish population, in agreement with previous data from our country and other Mediterranean countries (France, Italy), but different to Northern Europe or North America. There was a significant increase of PAVM associated with HHT1 over HHT2 in these families.</p
New VVV Survey Globular Cluster Candidates in the Milky Way Bulge
© 2017 The American Astronomical Society. All rights reserved.It is likely that a number of Galactic globular clusters remain to be discovered, especially toward the Galactic bulge. High stellar density combined with high and differential interstellar reddening are the two major problems for finding globular clusters located toward the bulge. We use the deep near-IR photometry of the VISTA Variables in the Vía Láctea (VVV) Survey to search for globular clusters projected toward the Galactic bulge, and hereby report the discovery of 22 new candidate globular clusters. These objects, detected as high density regions in our maps of bulge red giants, are confirmed as globular cluster candidates by their color-magnitude diagrams. We provide their coordinates as well as their near-IR color-magnitude diagrams, from which some basic parameters are derived, such as reddenings and heliocentric distances. The color-magnitude diagrams reveal well defined red giant branches in all cases, often including a prominent red clump. The new globular cluster candidates exhibit a variety of extinctions (0.06 < A Ks < 2.77) and distances (5.3 < D < 9.5 kpc). We also classify the globular cluster candidates into 10 metal-poor and 12 metal-rich clusters, based on the comparison of their color-magnitude diagrams with those of known globular clusters also observed by the VVV Survey. Finally, we argue that the census for Galactic globular clusters still remains incomplete, and that many more candidate globular clusters (particularly the low luminosity ones) await to be found and studied in detail in the central regions of the Milky Way.Peer reviewedFinal Accepted Versio
Superplasticidad de aceros de baja aleación con grano ultrafino: Superplasticity of ultrafine grained low-alloy steels
Write Steels with ultrafine grained structure may present superplastic behavior at specific temperatures and strain rates that allow the grain boundary sliding mechanisms to be activated. The superplastic behavior implies deformation to large strains by grain-boundary sliding with diffusional accommodation, as described by the Ashby-Verrall model. The work presents high temperature tension tests in a low carbon, low alloy steel obtained by advanced thermomechanical controlled rolling processes, showing at 800°C elongations as high as 200%.The microstructure of the steel was analyzed in order to identify ferrite and pearlite grain boundaries, and their interaction after the specimens were deformed. Microanalytical techniques (Optical and SEM) show evidence of: damage growth that prevents the development of higher elongations to failure, non-uniform flow (relative movement-rotation of grains in close proximity to each other) and intergranular non-superplastic deformation (quasi-uniform flow); thus leading to premature failure.Los aceros con estructura de grano ultrafino pueden presentar comportamiento superplástico a temperaturas y velocidades de deformación específicas, que faciliten la activación de los mecanismos de deslizamiento de fronteras de grano. El comportamiento superplástico implica deformaciones elevadas por procesos de deslizamiento de fronteras de grano con acomodo de materia por difusión, tal como lo describe el modelo de Ashby-Verrall. El trabajo presenta pruebas de tensión a temperatura elevada en aceros de bajo carbono y baja aleación obtenidos por procesos avanzados de rolado controlados termomecánicamente, mostrando a 800°C elongaciones de hasta el 200%. La microestructura del acero se analizó para poder identificar las fronteras de grano de la ferrita y de la perlita, y su interacción después de que la probeta fue deformada. Las técnicas de microanálisis (óptico y SEM) muestran evidencia de: crecimiento de defectos que impiden alcanzar elongaciones a ruptura mayores, flujo no uniforme (movimiento-rotación relativo de granos próximos entre sí) y deformación intergranular nosuperplástica(flujo cuasi-uniforme), resultando todo esto en fractura prematura
Versatile Application of rfid technology to commercial and laboratory research contexts: fresh fish supply-chain and behavioural tests
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