1,678 research outputs found
Estudio preliminar del comportamiento de rellenos sanitarios como biodigestores a escala de laboratorio
Teniendo en cuenta la situacion desfavorable con que cuentan los sitios de disposicion final del RSU en la ciudad de Santa Clara, Cuba, y las futuras proyecciones de construcción de rellenos sanitarios controlados, propusimos como objetivo general del presente trabajo evaluar el proceso de degradación anaerobia en los rellenos sanitarios como biodigestores a escala de laboratorio en sus etapas iniciales, teniendo en cuenta la gestion y composición de los RSU en la ciudad de Santa Clara. Primeramente se realizó una preparación y caracterización de los residuosa introducir en los digestores, y comenzar el proceso demonitoreo durante 10 semanas según diseño de experimento 22, teniendo en cuenta la recirculacion de lixiviados y el uso de suelo como material de cobertura. Las tecnicas involucradas en el monitoreo y seguimiento de la digestión anaerobia fueron: pH, DQO, Conductividad, y N-NH4+ en los lixiviados. La selección de variables monitoreadas viene dada por ser la DQO y el pH los parámetros que brindan mayor información sobre el transcurso de las diferentes etapas de la digestión anaerobia. A su vez indican si se logra alcanzar o no la estabilización de los Residuos Solidos Organicos (RSO); ya que valores de DQO en los lixiviados por debajo de 2000 mg/L son indicativos de un relleno sanitario estabilizado (Hernández-Berriel etal., 2011), (Mehta et al., 2002). Al analizar los resultados de las variables monitoreadas para los 4 reactores se aprecian valores de pH y DQO indicativos de lixiviados de rellenos sanitarios jovenes y en etapas iniciales de degradación (acidogenesis). Este resultado contrasta con la baja producción de biogás observada en todos los reactores. Los resultados también indican un alto poder contaminante de los lixiviados, poniendose de manifiesto con valores de DQO que llegan hasta 60 g/L, corroborandose lo que se plantea en la literatura sobre estos líquidos; los que pueden ser de 100 a 120 veces más contaminantes que las aguas residuales cloacales (Hernández-Berriel etal., 2008), (Suna et al., 2008)
Thickness of the buccal bone wall and root angulation in the maxilla and mandible: an approach to cone beam computed tomography
Background: The objective of this paper is to anatomically describe the bone morphology in the maxillary and mandibular tooth areas, which might help in planning post-extraction implants. Methods: CBCT images (Planmeca ProMax 3D) of 403 teeth (208 upper teeth and 195 lower teeth) were obtained from 49 patients referred to the Dental School of Seville from January to December 2014. The thickness of the facial wall was measured at the crest, point A, 4mm below, point B, and at the apex, point C. The second parameter was the angle formed between the dental axis and the axis of the basal bone. Results: A total of 403 teeth were measured. In the maxilla, 89.4% of incisors, 93.94% of canines, 78% of premolars and 70.5% of molars had a buccal bone wall thickness less than the ideal 2mm. In the mandible, 73.5% of incisors, 49% of canines, 64% of premolars and 53% of molars had <1mm buccal bone thickness as measured at point B. The mean angulation in the maxilla was 11.67±6.37° for incisors, 16.88±7.93° for canines, 13.93±8.6° for premolars, and 9.89±4.8° for molars. In the mandible, the mean values were 10.63±8.76° for incisors, 10.98±7.36° for canines, 10.54±5.82° for premolars and 16.19±11.22° for molars. Conclusions: The high incidence of a buccal wall thickness of less than 2mm in over 80% of the assessed sites indicates the need for additional regeneration procedures, and several locations may also require custom abutments to solve the angulation problems for screw-retained crowns
Estudio preliminar del comportamiento de rellenos sanitarios como biodigestores a escala de laboratorio
Teniendo en cuenta la situacion desfavorable con que cuentan los sitios de disposicion final del RSU en la ciudad de Santa Clara, Cuba, y las futuras proyecciones de construcción de rellenos sanitarios controlados, propusimos como objetivo general del presente trabajo evaluar el proceso de degradación anaerobia en los rellenos sanitarios como biodigestores a escala de laboratorio en sus etapas iniciales, teniendo en cuenta la gestion y composición de los RSU en la ciudad de Santa Clara. Primeramente se realizó una preparación y caracterización de los residuosa introducir en los digestores, y comenzar el proceso demonitoreo durante 10 semanas según diseño de experimento 22, teniendo en cuenta la recirculacion de lixiviados y el uso de suelo como material de cobertura. Las tecnicas involucradas en el monitoreo y seguimiento de la digestión anaerobia fueron: pH, DQO, Conductividad, y N-NH4+ en los lixiviados. La selección de variables monitoreadas viene dada por ser la DQO y el pH los parámetros que brindan mayor información sobre el transcurso de las diferentes etapas de la digestión anaerobia. A su vez indican si se logra alcanzar o no la estabilización de los Residuos Solidos Organicos (RSO); ya que valores de DQO en los lixiviados por debajo de 2000 mg/L son indicativos de un relleno sanitario estabilizado (Hernández-Berriel etal., 2011), (Mehta et al., 2002). Al analizar los resultados de las variables monitoreadas para los 4 reactores se aprecian valores de pH y DQO indicativos de lixiviados de rellenos sanitarios jovenes y en etapas iniciales de degradación (acidogenesis). Este resultado contrasta con la baja producción de biogás observada en todos los reactores. Los resultados también indican un alto poder contaminante de los lixiviados, poniendose de manifiesto con valores de DQO que llegan hasta 60 g/L, corroborandose lo que se plantea en la literatura sobre estos líquidos; los que pueden ser de 100 a 120 veces más contaminantes que las aguas residuales cloacales (Hernández-Berriel etal., 2008), (Suna et al., 2008)
An X-ray Study of Local Infrared Bright Galaxies
We are carrying out detailed study of the X-ray and infrared (IR) properties
of a sample of local (d < 70 Mpc) luminous infrared galaxies (LIRGs) using
XMM-Newton and Spitzer (imaging and spectroscopy). The main goal is to study
the extreme processes of star formation and/or active galactic nuclei (AGN)
taking place in this cosmologically important class of galaxies. In this
proceedings we present the preliminary results obtained from the analysis of
the XMM-Newton X-ray images and the X-ray spectral modeling.Comment: 5 pages, to appear in Highlights of Spanish Astrophysics VI,
Proceedings of the IX Scientific Meeting of the Spanish Astronomical Society
held on September 13-17, 2010, in Madrid, Spai
El epítome de métrica grecolatina de Calvete de Estrella (Madrid, Biblioteca Nacional, ms. 4237)
This article deals with an unpublished Latin treatise on classical metre by Calvete de Estrella, De uersuum genere epitome, Salamanca 1586, which is kept on the National Library in Madrid, and also offers some observations about other works of this humanist and the Spanish scholarship of his time. The main sources of Calvete's treatise are identified by comparing several items of it with Jacob Micyllus' De re metrica liber I, and the some Greek technopaegnia in the edition of Theocritus by Henri Estienne.Proyecto DGICyT FFI2011-2963
Optical detection of the radio supernova SN 2000ft in the circumnuclear region of the luminous infrared galaxy NGC 7469
SN 2000ft is detected in two independent Planetary Camera images (F547W and
F814W) taken May 13, 2000, about two months before the predicted date of the
explosion (July 19, 2000), based on the analysis of its radio light evolution
by Alberdi and collaborators. The apparent optical magnitudes and red color of
SN 2000ft indicate that it is observed through an extinction of at least A=
3.0 magnitudes. The extinction corrected lower limit to the absolute visual
magnitude (M 18.0), identifies SN 2000ft as a luminous supernova
in the optical, as other luminous radio supernovae before. SN 2000ft exploded
in a region located at only 0.1 arcsec (i.e. 34 +/- 3 pc) west of a faint
cluster (C24). No parent cluster is identified within the detection limits of
the HST short exposures. The unambiguous detection of SN 2000ft in the visual
shows that multi-epoch sub-arcsecond (FWHM less than 0.1 arcsec) optical
imaging is also a valid tool that should be explored further to detect
supernovae in the dusty (circum)nuclear regions of (U)LIRGs
Do as I do, and also as I say: monetary policy impact on Brazil’s financial markets
We analyze how Brazilian financial markets, in particular interest rate futures, react to monetary policy in terms of both deeds (that is, changes in the policy rate) and words (that is, central bank communication). Using daily data from 2005 to 2014, we find that interest futures rates react in the expected direction to both the central bank’s actions and its words: futures rates rise (fall) after both an increase (decrease) in the reference interest rate and a hawkish (dovish) communication by the Central Bank of Brazil. We also find that the Central Bank’s words create noise, since they increase the volatility of futures rates. Our analysis further reveals that the effectiveness of monetary policy communication increased after the 2008 international crisis, as measured by its larger impact on future rates and reduced volatility. At the same time, deeds became less relevant: the effect of changes in the Central Bank’s policy rate on futures rates declined
Hawking Radiation from Universal Horizons
The persistence of a suitable notion of black hole thermodynamics in Lorentz
breaking theories of gravity is not only a non-trivial consistency test for
such theories, it is also an interesting investigation {\em per se}, as it
might help us identifying the crucial features at the root of these surprising
laws governing such purely gravitational objects. In past investigations,
controversial findings were presented in this sense. With the aim of settling
this issue, we present here two complementary derivations of Hawking radiation
in geometries endowed with universal horizons: a novel feature of back holes in
Lorentz breaking theories of gravity which reproduces several properties
normally characterizing Killing horizons. We find that both the derivations
agree on the fact that the Hawking temperature associated to these geometries
is set by the generalized universal horizon peeling surface gravity, as
required for consistency with extant derivations of the first law of
thermodynamics for these black holes. We shall also comment on the
compatibility of our results with previous alternative derivations and on their
significance for the survival of the generalized second law of black hole
thermodynamics in Lorentz breaking theories of gravity
A High Spatial Resolution Mid-Infrared Spectroscopic Study of the Nuclei and Star-Forming Regions in Luminous Infrared Galaxies
We present a high spatial (diffraction-limited) resolution (~0.3")
mid-infrared (MIR) spectroscopic study of the nuclei and star-forming regions
of 4 local luminous infrared galaxies (LIRGs) using T-ReCS on the Gemini South
telescope. We investigate the spatial variations of the features seen in the
N-band spectra of LIRGs on scales of ~100 pc, which allow us to separate the
AGN emission from that of the star formation (SF). We compare our Gemini T-ReCS
nuclear and integrated spectra of LIRGs with those obtained with Spitzer IRS.
The 9.7um silicate absorption feature is weaker in the nuclei of the LIRGs than
in the surrounding regions. This is probably due to the either clumpy or
compact environment of the central AGN or young, nuclear starburst. We find
that the [NeII] luminosity surface density is tightly and directly correlated
with that of Pa-alpha for the LIRG star-forming regions (slope of 1.00+-0.02).
Although the 11.3um PAH feature shows also a trend with Pa-alpha, this is not
common for all the regions. We also find that the [NeII]\Pa-alpha ratio does
not depend on the Pa-alpha equivalent width (EW), i.e., on the age of the
ionizing stellar populations, suggesting that, on the scales probed here, the
[NeII] emission line is a good tracer of the SF activity in LIRGs. On the other
hand, the 11.3um PAH\Pa-alpha ratio increases for smaller values of the
Pa-alpha EW (increasing ages), indicating that the 11.3um PAH feature can also
be excited by older stars than those responsible for the Pa-alpha emission.
Additional high spatial resolution observations are essential to investigate,
in a statistical way, the star formation in local LIRGs at the smallest scales
and to probe ultimately whether they share the same physical properties as
high-z LIRGs, ULIRGs and submillimiter galaxies.Comment: 23 pages (apjstyle), 19 figures, accepted for publicacion in Ap
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