940 research outputs found
The role of soil biotic processes in the search of quantitative indexes of soil quality
Non-Peer ReviewedMonitoring soil quality involves measurements of soil properties over periods of several years. This article
examines the potential role of chemical SOM composition and of soil biotic processes as faster indexes of soil quality. Soil quality was quantified on the basis of individual soil attributes and time. Chemical characterization of soil organic matter by solid 13C-NMR and Py-FIMS showed that a degraded Gleysol cropped to corn during 25 years suffered C losses from all chemical functional groups. Surprisingly, aromatic-C was lost at proportional higher rates than aliphatic-C. These results indicate that chemical composition of SOM determined by quantitative nondestructive methods can be used as quality indexes in
agricultural soils. Biotic processes reflect changes in soil quality over shorter periods than total or type of SOM. Microbial specific respiration (qCO2) is a soil attribute that consistently reflected differences in soil quality. It was hypothesized that qCO2 , the microbial adenylate energy charge and anabolic reduction charge may permit to asses soil quality over monitoring periods of weeks to <5y
Detection and Mapping of Decoupled Stellar and Ionized Gas Structures in the Ultraluminous Infrared Galaxy IRAS 12112+0305
Integral field optical spectroscopy with the INTEGRAL fiber-fed system and
HST optical imaging are used to map the complex stellar and warm ionized gas
structure in the ultraluminous infrared galaxy IRAS 12112+0305. Images
reconstructed from wavelength-delimited extractions of the integral field
spectra reveal that the observed ionized gas distribution is decoupled from the
stellar main body of the galaxy, with the dominant continuum and emission-line
regions separated by projected distances of up to 7.5 kpc. The two optical
nuclei are detected as apparently faint emission-line regions, and their
optical properties are consistent with being dust-enshrouded weak-[OI] LINERs.
The brightest emission-line region is associated with a faint (m_{I}= 20.4),
giant HII region of 600 pc diameter, where a young (about 5 Myr) massive
cluster of about 2 10 dominates the ionization.
Internal reddening towards the line-emitting regions and the optical nuclei
ranges from 1 to 8 magnitudes, in the visual. Taken the reddening into aacount,
the overall star formation in IRAS 12112+0305 is dominated by starbursts
associated with the two nuclei and corresponding to a star formation rate of 80
yr.Comment: 2 figures, accepted to Ap.J. Letter
Dryland salinity: a multi-disciplinary conceptual model designed for on-farm salinity control
Non-Peer Reviewe
LINER-like Extended Nebulae in ULIRGs: Shocks Generated by Merger Induced Flows
In this work we studied the two-dimensional ionization structure of the
circumnuclear and extranuclear regions in a sample of six low-z Ultraluminous
Infrared Galaxies using Integral Field Spectroscopy. The ionization conditions
in the extranuclear regions of these galaxies (~5-15 kpc) are typical of LINERs
as obtained from the Veilleux-Osterbrock line ratio diagnostic diagrams. The
range of observed line ratios is best explained by the presence of fast shocks
with velocities of 150 to 500 km s^{-1}, while the ionization by an AGN or
nuclear starburst is in general less likely. The comparison of the
two-dimensional ionization level and velocity dispersion in the extranuclear
regions of these galaxies shows a positive correlation, further supporting the
idea that shocks are indeed the main cause of ionization.
The origin of these shocks is also investigated. Despite the likely presence
of superwinds in the circumnuclear regions of these systems, no evidence for
signatures of superwinds such as double velocity components are found in the
extended extranuclear regions. We consider a more likely explanation for the
presence of shocks, the existence of tidally induced large scale gas flows
caused by the merging process itself, as evidenced by the observed velocity
fields characterized by peak-to-peak velocities of 400 km s^{-1}, and velocity
dispersions of up to 200 km s^{-1}.Comment: 21 pages, 5 figures, accepted for publication in The Astrophysical
Journa
Full-scale dynamometer tests of composite railway brake shoes including latxa sheep wool fibers
The main target of the present work is to characterize the effect of the inclusion of natural sheep wool (SW) into a railway brake block composition and then to compare it to that of a set of three organic fibers commonly used in the friction material industry: aramid fiber (AF), cellulose fiber (CF) and polyacrylonitrile fiber (PAN). In order to achieve this, 4 versions of the same friction material with a fixed amount of each organic fiber were produced and one more sample was manufactured including no organic fibers. The characterization work consisted of friction tests on a full-scale railway test rig. Then, the samples were SEM analyzed in order to characterize the tested surface microstructure. It was found that all organic fibers helped achieve a more stable bedding, and showed lower friction in wet conditions. They also affected the recovery %. Pictures of the blocks were taken after certain phases of the test and, although the failure sequence remained the same for all samples, the organic fibers very much influenced the magnitude of the wear rates. Sheep wool led to better results than cellulose. No final conclusions could be drawn with respect to metal pick-up. SEM analysis evidenced primary and secondary plateaus, but no significant differences were observed depending on the fiber nature. Finally, a Life Cycle Assessment with a “from cradle to gate” perspective was carried out. Ecoinvent v3.5 database and CML and ReCiPe Endpoint methodologies were used to evaluate the environmental impact create by the five brake block materials. Overall, cellulose, PAN and sheep wool brake blocks show slightly lower environmental impacts that the base material or than aramid fibers. Therefore, Latxa sheep wool offers a good balance between low cost, adequate wear rates and environmental impact, making it a compelling substitute for cellulose fibers
Diseño y desarrollo de un espectrómetro óptico versátil de bajo coste
[EN] In this work, the processes of designing, developing and prototyping
an instrument to measure the visible spectrum is shown in detail. The
objective is to obtain a low-cost device, reproducible and technically
competitive with the commercial docent models. The obtained device
is portable, adaptable, compact, economic and with high connectivity.
The core of the project is the software, and its key point is the compatibility
with any commercial camera and it can be run in different
operative systems. For this prototype a commercial camera with USB
connection has been considered in order to find a balance between
price and resolution for the resulting device.[ES] En este trabajo se detalla el proceso de diseño, desarrollo
y prototipado de un sistema de medida del espectro visible.
El objetivo que hay que cumplir es la obtención de un dispositivo
reproducible, competitivo en el aspecto técnico con
modelos comerciales de docencia actuales, y económico. El
dispositivo resultante reúne las características de ser portátil,
versátil, compacto, económico y con alta conectividad.
El centro del proyecto es el software, que como característica
clave permite ser utilizado prácticamente con cualquier
cámara comercial y ser ejecutado desde distintos sistemas
operativos. El prototipado se ha realizado con una cámara
comercial con conexión USB con el fin de encontrar un
equilibrio entre asequibilidad y resolución del producto final.
Tiene un precio 20 veces más económico y una resolución
similar al espectrofotómetro comercial utilizado como referencia.Este trabajo ha sido financiado por el Ministerio de Economía y Competitividad y FEDER (Proyecto DPI2015-71256-R) y por la Generalitat Valenciana (Proyecto PROMETEOII-2014-072).Ferrando, V.; Monreal, J.; Furlan, WD.; Monsoriu Serra, JA. (2017). Diseño y desarrollo de un espectrómetro óptico versátil de bajo coste. Tecnica Industrial. (318):48-52. https://doi.org/10.23800/9984S485231
Hospital volume and outcomes for acute pulmonary embolism: Multinational population based cohort study
[Objectives] To evaluate the association between experience in the management of acute pulmonary embolism, reflected by hospital case volume, and mortality.[Design] Multinational population based cohort study using data from the Registro Informatizado de la Enfermedad TromboEmbólica (RIETE) registry between 1 January 2001 and 31 August 2018.[Setting] 353 hospitals in 16 countries.[Participants] 39 257 consecutive patients with confirmed diagnosis of acute symptomatic pulmonary embolism.[Main] outcome measure Pulmonary embolism related mortality within 30 days after diagnosis of the condition.[Results] Patients with acute symptomatic pulmonary embolism admitted to high volume hospitals (>40 pulmonary embolisms per year) had a higher burden of comorbidities. A significant inverse association was seen between annual hospital volume and pulmonary embolism related mortality. Admission to hospitals in the highest quarter (that is, >40 pulmonary embolisms per year) was associated with a 44% reduction in the adjusted odds of pulmonary embolism related mortality at 30 days compared with admission to hospitals in the lowest quarter (<15 pulmonary embolisms per year; adjusted risk 1.3% v 2.3%; adjusted odds ratio 0.56 (95% confidence interval 0.33 to 0.95); P=0.03). Results were consistent in all sensitivity analyses. All cause mortality at 30 days was not significantly reduced between the two quarters (adjusted odds ratio 0.78 (0.50 to 1.22); P=0.28). Survivors showed little change in the odds of recurrent venous thromboembolism (odds ratio 0.76 (0.49 to 1.19)) or major bleeding (1.07 (0.77 to 1.47)) between the low and high volume hospitals.[Conclusions] In patients with acute symptomatic pulmonary embolism, admission to high volume hospitals was associated with significant reductions in adjusted pulmonary embolism related mortality at 30 days. These findings could have implications for management strategies.Peer reviewe
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