180 research outputs found
Antecedentes para una historia del hombre santiagueño en la región chaqueña
Santiago de Estero se proyecta desde lo más remoto de nuestro pasado histórico como un cofre que guarda las puras esencias del alma tradicional argentina. Una inmensa llanura enclavada en el centro del mediterráneo del viejo país confiere notable uniformidad al relieve, y hace de estatierra un verdadero corredor interpuesto entre el litoral y el norte en una mole geográfica, cuya valoración trasciendesus linderos territoriales."Por mucho mayor que sea cuantitativamente la importancia de esas dos regiones -ha escrito Bernardo Canal Feijóo- no podrá dejar de ser relativa, mientras éstas no pueden prescindir de Santiago; y el problema consiste, precisamente en que, por sus masas y su ubicación, Santiago es para esas dos regiones imprescindible o inevitable".Academia Nacional de Agronomía y Veterinaria (ANAV
Antecedentes para una historia del hombre santiagueño en la región chaqueña
Santiago de Estero se proyecta desde lo más remoto de nuestro pasado histórico como un cofre que guarda las puras esencias del alma tradicional argentina. Una inmensa llanura enclavada en el centro del mediterráneo del viejo país confiere notable uniformidad al relieve, y hace de estatierra un verdadero corredor interpuesto entre el litoral y el norte en una mole geográfica, cuya valoración trasciendesus linderos territoriales."Por mucho mayor que sea cuantitativamente la importancia de esas dos regiones -ha escrito Bernardo Canal Feijóo- no podrá dejar de ser relativa, mientras éstas no pueden prescindir de Santiago; y el problema consiste, precisamente en que, por sus masas y su ubicación, Santiago es para esas dos regiones imprescindible o inevitable".Academia Nacional de Agronomía y Veterinaria (ANAV
Synthesis and luminescence properties of electrodeposited ZnO Films
ZnO films have been grown on gold (111) by electrodeposition using two
different OH- sources, nitrate and peroxide, in order to obtain a comparative
study between these films. The morphology, structural and optical
characterization of the films were investigated depending on the solution used
(nitrate and peroxide) and the applied potential. Scanning Electron Microscopy
pictures show different morphologies in each case. X-Ray Diffraction confirms
that the films are pure ZnO oriented along the (0002) direction. ZnO films have
been studied by photoluminescence to identify the emission of defects in the
visible range. A consistent model that explains the emissions for the different
electrodeposited ZnO films is proposed. We have associated the green and yellow
emissions to a transition from the donor OH- to the acceptor zinc vacancies
(VZn-) and to interstitial oxygen (Oi0), respectively. The orange-red emission
is probably due to transitions from the conducting band to Oi- and OZn 0
defects and the infrared emission to transition from these Oi -/2- and OZn 0/-
defects to the valence band.Comment: 17 pages, 1 Table and 10 figure
Spatially resolved X-ray excited optical luminescence
Spatially resolved luminescence distributions in semiconductor heterostructures were investigated by core level excitation using hard X-ray (sub-) microbeams. Compact and mobile XEOL instruments have been developed and well adapted on the hard X-ray beamline ID22 of the European Synchrotron Radiation Facility for different wavelength collection ranges: UV-VIS and NIR. Linked by multimode optical fibers, their special designs provide precise scanning microscopy and allow easy access for multiple detection modes. Based on the hard X-ray microprobe station of ID22, details of the equipments, spectral data and representative examples are briefly described. Data collections from InAs and InGaN quantum heterostructures support the excellent performance of the optical devices. © 2011 Elsevier B.V. All rights reserved.This work was partially supported by the NANOWIRING Marie Curie ITN (EU project No. PITN-GA-2010-265073).Peer Reviewe
Media reporting: facts, nothing but facts?
This IRIS Special examines the principles of accuracy, objectivity and fairness in news and current affairs coverage by European media organisations. The issue is explored from a number of perspectives, including from that of media organisations, the Council of Europe, the European Court of Human Rights, member states, and judicial and regulatory bodies. It also includes chapters on a number of Council of Europe member states, discussing the regulatory framework that impacts upon this issue, including national legislation, case law, regulatory codes, and regulatory enforcement
Long term variations measurement of electromagnetic field exposures in Alcalá de Henares (Spain)
Electromagnetic radiowave exposure is a major concern in most countries due to possible adverse health effects. Over the last 10 years, many technological changes (digital television, mobile technologies, wireless networks…) have led to variations in the electromagnetic field (EMF) levels.
A large number of studies devoted to the analysis of EMF levels with personal dosimeters or computer models of the exposure of mobile stations have been conducted. However, the study of the exposure values, taking into account all the existing sources, and their evolution in a wide area, using measurements, has rarely been performed.
In this paper, we provide a comparison of the EMF exposure levels for the city of Alcalá de Henares (Spain) over a ten-year period using a broadband isotropic probe in the range from 100 kHz to 3 GHz. A statistical and spatial analysis of the measurements and their variations are also presented for the study of the global and local variations.
The measured values in the period from 2006 to 2015 were ranging from 0.02 to 2.05 V/m. Our global results show a moderate increase from 2006 to 2010 and they are almost invariant from 2010 to 2015. Although the whole dataset does not have relevant statistical difference, we have found marked local differences. In the city areas where the population density has remained unaltered, we have measured lower exposure levels. Conversely, new urban and industrial developments have demanded new resources, which have potentially contributed to the observed increase in the measured electric field levels within these areas
Pathway to an excitonic coherence
This paper discusses the combined effects of optical excitation power,
interface roughness, lattice temperature, and applied magnetic fields on the
spin-coherence of excitonic states in GaAs/AlGaAs multiple quantum wells. For
low optical powers, at lattice temperatures between 4 K and 50 K, the
scattering with acoustic phonons and short-range interactions appear as the
main decoherence mechanisms. Statistical fluctuations of the band-gap however
become also relevant in this regime and we were able to deconvolute them from
the decoherence contributions. The circularly polarized
magneto-photoluminescence unveils a non-monotonic tuning of the coherence for
one of the spin components at low magnetic fields. This effect has been
ascribed to the competition between short-range interactions and spin-flip
scattering, modulated by the momentum relaxation time
Relationship between damage and mortality in juvenile-onset systemic lupus erythematosus: Cluster analyses in a large cohort from the Spanish Society of Rheumatology Lupus Registry (RELESSER)
Objectives: To identify patterns (clusters) of damage manifestation within a large cohort of juvenile SLE (jSLE) patients and evaluate their possible association with mortality.
Methods: This is a multicentre, descriptive, cross-sectional study of a cohort of 345 jSLE patients from the Spanish Society of Rheumatology Lupus Registry. Organ damage was ascertained using the Systemic Lupus International Collaborating Clinics Damage Index. Using cluster analysis, groups of patients with similar patterns of damage manifestation were identified and compared.
Results: Mean age (years) ± S.D. at diagnosis was 14.2 ± 2.89; 88.7% were female and 93.4% were Caucasian. Mean SLICC/ACR DI ± S.D. was 1.27 ± 1.63. A total of 12 (3.5%) patients died. Three damage clusters were identified: Cluster 1 (72.7% of patients) presented a lower number of individuals with damage (22.3% vs. 100% in Clusters 2 and 3, P < 0.001); Cluster 2 (14.5% of patients) was characterized by renal damage in 60% of patients, significantly more than Clusters 1 and 3 (P < 0.001), in addition to increased more ocular, cardiovascular and gonadal damage; Cluster 3 (12.7%) was the only group with musculoskeletal damage (100%), significantly higher than in Clusters 1 and 2 (P < 0.001). The overall mortality rate in Cluster 2 was 2.2 times higher than that in Cluster 3 and 5 times higher than that in Cluster 1 (P < 0.017 for both comparisons).
Conclusions: In a large cohort of jSLE patients, renal and musculoskeletal damage manifestations were the two dominant forms of damage by which patients were sorted into clinically meaningful clusters. We found two clusters of jSLE with important clinical damage that were associated with higher rates of mortality, especially for the cluster of patients with predominant renal damage. Physicians should be particularly vigilant to the early prevention of damage in this subset of jSLE patients with kidney involvement
Associated factors to serious infections in a large cohort of juvenile-onset systemic lupus erythematosus from Lupus Registry (RELESSER).
Objective: To assess the incidence of serious infection (SI) and associated factors in a large juvenile-onset systemic lupus erythematosus (jSLE) retrospective cohort. Methods: All patients in the Spanish Rheumatology Society Lupus Registry (RELESSER) who meet =4 ACR-97 SLE criteria and disease onset <18 years old (jSLE), were retrospectively investigated for SI (defined as either the need for hospitalization with antibacterial therapy for a potentially fatal infection or death caused by the infection). Standardized SI rate was calculated per 100 patient years. Patients with and without SI were compared. Bivariate and multivariate logistic and Cox regression models were built to calculate associated factors to SI and relative risks. Results: A total of 353 jSLE patients were included: 88.7% female, 14.3 years (± 2.9) of age at diagnosis, 16.0 years (± 9.3) of disease duration and 31.5 years (±10.5) at end of follow-up. A total of 104 (29.5%) patients suffered 205 SI (1, 55.8%; 2-5, 38.4%; and =6, 5.8%). Incidence rate was 3.7 (95%CI: 3.2–4.2) SI per 100 patient years. Respiratory location and bacterial infections were the most frequent. Higher number of SLE classification criteria, SLICC/ACR DI score and immunosuppressants use were associated to the presence of SI. Associated factors to shorter time to first infection were higher number of SLE criteria, splenectomy and immunosuppressants use. Conclusions: The risk of SI in jSLE patients is significant and higher than aSLE. It is associated to higher number of SLE criteria, damage accrual, some immunosuppressants and splenectomy
Efeitos da sequência de branqueamento na ação de alvejantes óticos em celulose kraft de eucalipto
- …