3,803 research outputs found
Simple Method to Synthesize Functionalized Carbon Nanotubes Employing Cobalt Nitrate and Acetone by Using Spray Pyrolysis Deposition Technique
Recently alcohols and ketones have been employed to sensitize CNT by CVD. A study has shown the importance of the chemical nature of those carbon precursors on the characteristics of the CNT (carbon nanotubes) obtained. In the present work we show the influence of the catalyst employed on the synthesis of functionalized multiwall carbon nanotubes (MWCNTs) utilizing acetone as carbon source and cobalt nitrate Co(NO3)2 as catalyst
ACV de la manufactura regional de ladrillos
This document presents a Life Cycle Assessment (LCA) study to quantify the environmental cradle-to-gate impact of the manufacture of brick for the construction industry, produced with material of igneous source. Its mineral composition and thermal isolation properties were characterized for use in real estate construction. The LCA results for brick manufacture using this material identified the greatest environmental impact to be associated with material extraction and its proportional cement content. Additionally, this document presents an evaluation of the environmental impact of the manufacturing process by comparing traditional fired clay brick and brick of the material under study. In conclusion, the studied material shows thermal insulation qualities and suitability for the manufacture of bricks with low incorporated energy.Este trabajo presenta un estudio de Análisis de Ciclo de Vida (ACV) para cuantificar los impactos ambientales de la cuna a la puerta de la manufactura de ladrillos para la industria de la construcción, fabricados de un material de origen ígneo. Se caracterizó su composición mineralógica y propiedades de aislamiento térmico para ser usado en la construcción de inmuebles. Los resultados ACV de la fabricación de ladrillos de este material, identificaron la mayor contribución a los impactos ambientales asociados a la extracción del material y la cantidad proporcional de cemento. Adicionalmente, se presenta una evaluación comparativa del impacto ambiental entre la manufactura de un ladrillo tradicional de arcilla cocido y de un ladrillo del material en estudio. En conclusión el material estudiado muestra cualidades de aislamiento térmico y es adecuado para la fabricación de ladrillos con baja energía incorporada
Molluscicide Effect of Sapindus saponaria Fruit on Galba cubensis, an Intermediate Host of Fasciolosis in Cuba
Galba cubensis is the main intermediate host of Fasciola hepatica in Cuba. The aim of this paper was to demonstrate the molluscicide effect of Sapindus saponaria L. on Galba cubensis in laboratory conditions, in order to recommend this plant for ecological control of this snail. Different concentrations of the hydroalcoholic extract of six-month old S. saponaria pericarp were tested on G. cubensis individuals, based on the methodology of the World Health Organization. The concentration gradient was used to determine LC50 and LC90, which then were tested to estimate the heartbeat frequency of these mollusks. The molluscicide effect of the plant extract was considerable (P≤0.01; R2=60.6), with concentration-dependent mortality and a drop of heartbeat frequency. Significant differences were observed between LC50=39.8 mg/L and LC90=67.9mg/L, in the test to lower heartbeat frequency (P≤0.01), and between LC90 and the control group (P≤0.01), but not between the control group and LC50 and (P=0.24). Molluscicide activity in the plant material was still present after six months of application, which was an important fact to recommend this plant as a candidate to control intermediate hosts of Fasciolosis in our region.Galba cubensis is the main intermediate host of Fasciola hepatica in Cuba. The aim of this paper was to demonstrate the molluscicide effect of Sapindus saponaria L. on Galba cubensis in laboratory conditions, in order to recommend this plant for ecological control of this snail. Different concentrations of the hydroalcoholic extract of six-month old S. saponaria pericarp were tested on G. cubensis individuals, based on the methodology of the World Health Organization. The concentration gradient was used to determine LC50 and LC90, which then were tested to estimate the heartbeat frequency of these mollusks. The molluscicide effect of the plant extract was considerable (P≤0.01; R2=60.6), with concentration-dependent mortality and a drop of heartbeat frequency. Significant differences were observed between LC50=39.8 mg/L and LC90=67.9mg/L, in the test to lower heartbeat frequency (P≤0.01), and between LC90 and the control group (P≤0.01), but not between the control group and LC50 and (P=0.24). Molluscicide activity in the plant material was still present after six months of application, which was an important fact to recommend this plant as a candidate to control intermediate hosts of Fasciolosis in our region
The dependence of oxygen and nitrogen abundances on stellar mass from the CALIFA survey
We analysed the optical spectra of HII regions extracted from a sample of 350
galaxies of the CALIFA survey. We calculated total O/H abundances and, for the
first time, N/O ratios using the semi-empirical routine HII-CHI-mistry, which,
according to P\'erez-Montero (2014), is consistent with the direct method and
reduces the uncertainty in the O/H derivation using [NII] lines owing to the
dispersion in the O/H-N/O relation. Then we performed linear fittings to the
abundances as a function of the de-projected galactocentric distances. The
analysis of the radial distribution both for O/H and N/O in the non-interacting
galaxies reveals that both average slopes are negative, but a non-negligible
fraction of objects have a flat or even a positive gradient (at least 10\% for
O/H and 4\% for N/O). The slopes normalised to the effective radius appear to
have a slight dependence on the total stellar mass and the morphological type,
as late low-mass objects tend to have flatter slopes. No clear relation is
found, however, to explain the presence of inverted gradients in this sample,
and there is no dependence between the average slopes and the presence of a
bar. The relation between the resulting O/H and N/O linear fittings at the
effective radius is much tighter (correlation coefficient = 0.80) than
between O/H and N/O slopes ( = 0.39) or for O/H and N/O in the
individual \hii\ regions ( = 0.37). These O/H and N/O values at the
effective radius also correlate very tightly (less than 0.03 dex of dispersion)
with total luminosity and stellar mass. The relation with other integrated
properties, such as star formation rate, colour, or morphology, can be
understood only in light of the found relation with mass.Comment: Accepted for publication in A&A. 20 pages, 19 figure
Undetectable Levels of CSF Amyloid-β Peptide in a Patient with 17β-Hydroxysteroid Dehydrogenase Deficiency
17β-hydroxysteroid dehydrogenase 10 (HSD10) deficiency is a rare X-linked inborn error of isoleucine catabolism. Although this protein has been genetically implicated in Alzheimer's disease pathogenesis, studies of amyloid-β peptide (Aβ) in patients with HSD10 deficiency have not been previously reported. We found, in a severely affected child with HSD10 deficiency, undetectable levels of Aβ in the cerebrospinal fluid, together with low expression of brain-derived neurotrophic factor, α-synuclein, and serotonin metabolites. Confirmation of these findings in other patients would help elucidating mechanisms of synaptic dysfunction in this disease, and highlight the role of Aβ in both early and late periods of life
Medida de autocontrol motor en tiradores de esgrima mediante el Tapping Test
El Tapping Test es una prueba neurológica habitual en las evaluaciones de los equipos nacionales de Cuba. Nuestro objetivo fue medir el autocontrol motor con esta prueba y su respuesta psicofisiológica en deportistas de la selección nacional de esgrima de Cuba. Comparando dos versiones del Tapping Test: modo 1 (habitual de lápiz-papel) y modo 2 (versión propuesta ejecutando acción técnica con el arma). Fueron 12 participantes (Medad = 22.19 años, DE = 3.50 años). Se utilizó un equipo de registro psicofisiológico inalámbrico (Biofeedback 2000). Los resultados, indican un autocontrol motor, siendo el modo 1 significativo F(1,10) = 44.29, p < .001; ya que la cantidad de toques o golpes fueron coherentes de acuerdo al ritmo de ejecución. El modo 2 tuvo una motilidad o aceleración significativa en las diferentes fases de la prueba F(1.58,15.8) = 8.14, p = .006, además mostró un mayor nivel de activación psicofisiológica. Este grupo de esgrimistas de alto nivel a pesar del incremento en la activación mostraron un autocontrol motor, ya que controlaron su movimiento de acuerdo al ritmo que se pedía (modo 1).The Tapping Test is a common neurological means of evaluating Cuba's national teams. Our objective was to assess self-control of motor abilities and the athletes' psychophysiological response by comparing two versions of the tapping test: mode 1 (normal pencil and paper) and mode 2 (technical action with the épée). The participants were made up of 12 athletes from the Cuban National Fencing Team (Mage = 22.19 years, SD = 3.50 years). We used wireless psychophysiological recording equipment (Biofeedback 2000). The results show self-control of motor abilities, mode 1 being significant F(1,10) = 44.29, p < .001 as the number of touches or hits was consistent with the execution rate. Mode 2 showed a motility or significant acceleration in the different phases of the test F(1.586, 15.85) = 8146, p = .006, plus a higher level of psychophysiological activation. This high-ranking group of fencers demonstrated self-control of their motor abilities despite increased activation, controlling their movements to match the requested pace (mode 1)
Assessment of ground deformation and seismicity in two areas of intense hydrocarbon production in the Argentinian Patagonia
The exploitation of both conventional and unconventional hydrocarbons may lead to still not well-known environmental consequences such as ground deformation and induced/triggered seismicity. Identifying and characterizing these effects is fundamental for prevention or mitigation purposes, especially when they impact populated areas. Two case studies of such effects on hydrocarbon-producing basins in Argentina, the Neuquén and the Golfo de San Jorge, are presented in this work. The intense hydrocarbon production activities in recent years and their potential link with the occurrence of two earthquakes of magnitude 4.9 and 5 near the operating well fields is assessed. A joint analysis of satellite radar interferometry and records of fluid injection and extraction demonstrate that, between 2017 and 2020, vertical ground displacements occurred in both study areas over active well fields that might indicate a correlation to hydrocarbon production activities. Coseismic deformation models of the two earthquakes constrain source depths to less than 2 km. The absence of seismicity before the beginning of the hydrocarbon activities in both areas, and the occurrence of the two largest and shallow earthquakes in the vicinity of the active well fields just after intensive production periods, points towards the potential association between both phenomena.Fil: Tamburini Beliveau, Guillermo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones y Transferencia de Santa Cruz. Universidad Tecnológica Nacional. Facultad Regional Santa Cruz. Centro de Investigaciones y Transferencia de Santa Cruz. Universidad Nacional de la Patagonia Austral. Centro de Investigaciones y Transferencia de Santa Cruz; ArgentinaFil: Grosso Heredia, Javier A.. Universidad Nacional del Comahue; ArgentinaFil: Béjar Pizarro, Marta. Instituto Geológico y Minero de España; EspañaFil: Pérez López, Raúl. Instituto Geológico y Minero de España; EspañaFil: Portela, Juan. Universidad Politécnica de Madrid; EspañaFil: Cismondi Duarte, Martín. Universidad Nacional de Córdoba. Instituto de Investigación y Desarrollo en Ingeniería de Procesos y Química Aplicada. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigación y Desarrollo en Ingeniería de Procesos y Química Aplicada; ArgentinaFil: Monserrat, Oriol. Centre Tecnològic de Telecomunicacions de Catalunya; Españ
Modelo de evaluación de la eficiencia energética y ambiental, de la estructura de actividades y la movilidad: región metropolitana de Barcelona: diseño funcional y resultados parciales
Se propone la construcción de un modelo de sostenibilidad funcional de áreas metropolitanas, basado en un modelo integrado de transporte y uso del suelo que permita evaluar explícitamente la eficiencia social, y sobre todo la eficiencia ambiental del funcionamiento de las ciudades en relación a los flujos y a las actividades instaladas en los territorios. El ámbito de implementación del modelo es la Región Metropolitana de Barcelona, y la unidad de análisis son sus 164 municipios.Peer Reviewe
Extraordinarily transparent compact metallic metamaterials
The design of achromatic optical components requires materials with high transparency and low dispersion. We show that although metals are highly opaque, densely packed arrays of metallic nanoparticles can be more transparent to infrared radiation than dielectrics such as germanium, even when the arrays are over 75% metal by volume. Such arrays form effective dielectrics that are virtually dispersion-free over ultra-broadband ranges of wavelengths from microns up to millimeters or more. Furthermore, the local refractive indices may be tuned by altering the size, shape, and spacing of the nanoparticles, allowing the design of gradient-index lenses that guide and focus light on the microscale. The electric field is also strongly concentrated in the gaps between the metallic nanoparticles, and the simultaneous focusing and squeezing of the electric field produces strong ‘doubly-enhanced’ hotspots which could boost measurements made using infrared spectroscopy and other non-linear processes over a broad range of frequencies.Imperial College London | Ref. EP/L015579/1Ministerio de Economía | Ref. CTM2014-58481RMinisterio de Economía | Ref. CTM2017-84050RMinisterio de Economía | Ref. CTQ2017-88648RMinisterio de Economía | Ref. RYC-2015-19107Ministerio de Economía | Ref. RYC2016-20331Xunta de Galicia | Ref. EM2014/035Generalitat de Cataluña | Ref. 2017SGR883URV y Banco Santander | Ref. 2017EXIT-08URV | Ref. 2017PFR-URV_B2-02FEDER | Ref. EP/L024926/1US Air Force Office of Scientific Research | Ref. FA9550-17-1-0300Consejo Superior de Investigaciones Científicas | Ref. INTRAMURALES 201750I03
Aperture effects on the oxygen abundance determinations from CALIFA data
This paper aims at providing aperture corrections for emission lines in a
sample of spiral galaxies from the Calar Alto Legacy Integral Field Area Survey
(CALIFA) database. In particular, we explore the behavior of the
log([OIII]5007/Hbeta)/([NII]6583/Halpha) (O3N2) and log[NII]6583/Halpha (N2)
flux ratios since they are closely connected to different empirical
calibrations of the oxygen abundances in star forming galaxies.
We compute median growth curves of Halpha, Halpha/Hbeta, O3N2 and N2 up to
2.5R_50 and 1.5 disk R_eff. The growth curves simulate the effect of observing
galaxies through apertures of varying radii. The median growth curve of the
Halpha/Hbeta ratio monotonically decreases from the center towards larger
radii, showing for small apertures a maximum value of ~10% larger than the
integrated one. The median growth curve of N2 shows a similar behavior,
decreasing from the center towards larger radii. No strong dependence is seen
with the inclination, morphological type and stellar mass for these growth
curves. Finally, the median growth curve of O3N2 increases monotonically with
radius. However, at small radii it shows systematically higher values for
galaxies of earlier morphological types and for high stellar mass galaxies.
Applying our aperture corrections to a sample of galaxies from the SDSS
survey at 0.02<=z<=0.3 shows that the average difference between fiber-based
and aperture corrected oxygen abundances, for different galaxy stellar mass and
redshift ranges, reaches typically to ~11%, depending on the abundance
calibration used. This average difference is found to be systematically biased,
though still within the typical uncertainties of oxygen abundances derived from
empirical calibrations. Caution must be exercised when using observations of
galaxies for small radii (e.g. below 0.5R_eff) given the high dispersion shown
around the median growth curves.Comment: Accepted for publication in Ap
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