4,027 research outputs found
Numerical analysis of the stability of the Electrohydrodynamic (EHD) electroconvection between two plates
The time evolution of the problem of Electrohydrodynamic (EHD)
convection in a liquid between two plates is analysed numerically. The equations are
nondimensionalized using the ion drift velocity and the viscous time scales. Following
the non-dimensionalisation of the respective model, two different techniques have been
used to describe the charge evolution, namely the Finite-Element Flux-Corrected
Transport Method and the Particle-In-Cell technique. The results obtained with the
two schemes, apart from showing good agreement, have revealed the appearance of a
two-roll structure not described in previous works. This is investigated in detail for
both strong and weak injection.Ministerio de ciencia y tecnología FQM-42
Determination of the Chiral Couplings L_10 and C_87 from Semileptonic Tau Decays
Using recent precise hadronic tau-decay data on the V-A spectral function,
and general properties of QCD such as analyticity, the operator product
expansion and chiral perturbation theory, we get accurate values for the QCD
chiral order parameters L_10^r(M_rho) and C_87^r(M_rho). These two low-energy
constants appear at order p^4 and p^6, respectively, in the chiral perturbation
theory expansion of the V-A correlator. At order p^4 we obtain L_10^r(M_rho) =
-(5.22\pm 0.06)10^{-3}. Including in the analysis the two-loop (order p^6)
contributions, we get L_10^r(M_rho) = -(4.06\pm 0.39)10^{-3} and C_87^r(M_rho)
= (4.89\pm 0.19)10^{-3}GeV^{-2}. In the SU(2) chiral effective theory, the
corresponding low-energy coupling takes the value \overline l_5 = 13.30 \pm
0.11 at order p^4, and \overline l_5 = 12.24 \pm 0.21 at order p^6.Comment: 17 pages, 3 figures, v2: Added reference, published versio
Asymmetric Hydrogenation of 1-alkyl and 1-aryl vinyl benzoates: a broad scope procedure for the highly enantioselective synthesis of 1-substituted ethyl benzoates
The enantioselective hydrogenation of enol esters of formula CH2=C(OBz)R with rhodium catalysts based on phosphine-phosphite ligands (P-OP) has been studied. The reaction has a broad scope and it is suitable for the preparation of products possessing a wide variety of R substituents. For the cases where R is a primary alkyl high catalyst activity (S/C = 500) and enantioselectivities (95-99 % ee) were obtained with a catalyst characterized by an ethane backbone and a PPh2 fragment. In contrast, for R = tBu a catalyst possessing a benzene backbone provided the best results (97 % ee). Derivatives with a cycloalkyl R substituent were particularly difficult substrates for this reaction. A broader catalyst screening was required for these substrates, which identified a catalyst possessing a P(m-xylyl)2 fragment as the most appropriate one, affording enantioselectivities between 90 and 95 % ee. Outstanding enantioselectivities (99 % ee) and high catalyst activity (S/C = 500-1000) were also obtained in the case of substrates bearing a Ph or a fluoroaryl R substituent. In addition, the system is also appropriate for the preparation of other synthetically useful esters as those for R = benzyl, 2-phenylethyl or Nphthalimido alkyl chains. Likewise, the hydrogenation of divinyl dibenzoates proceeded with very high diastero- and enantioselectivity, generating rather low amounts of the meso isomer (3-6 %). On the other hand, substrates with Br- and MeO- substituents at the phenyl benzoate ring, suitable for further functionalization, have also been examined. The results obtained indicate no detrimental effect of these substituents in the hydrogenation. Alternatively, the methodology has been applied to the highly enantioselective synthesis of deuterium isotopomers of 1-octyl benzoate bearing CDH2, CD2H or CD3 fragments. Finally, as a practical advantage of the present system, it has been observed that the high performance of the catalysts is retained in high concentrated solutions or even in the neat substrate, then minimizing both the amount of solvent added and the volume of the reactionJunta de Andalucía 2009/FQM-4832CSIC 201480E03 1Ministerio de Ciencia e Innovación CTQ2010- 14796/BQ
Morbilidad Asistida y morbilidad real por infecciones respiratorias agudas
ResumenEl presente trabajo aborda el estudio de la morbilidad por Infecciones Respiratorias Agudas (IRA) en áreas del municipio Lisa en Ciudad Habana, así como en localidades del municipio Isla de la Juventud (Cuba), con objeto de caracterizar algunos aspectos de la morbilidad por demanda de consultae identificar la morbilidad real. Alrededor del 90% de las consultas por IRA fueron por primera vez y en general la razón de éstas, respecto al seguimiento fue de 5,3. A través de la búsqueda activa de enfermos se obtuvieron las tasas de morbilidad real (TMR) entre valores de 110,4 y 163,4 casos por 1000 habitantes, que fueron muy superiores a las tasas de morbilidad por demanda de consulta (TMDC) en iguales periodos de tiempo. Resultado de la división de ambas tasas se obtuvo el«índice de morbilidad real» (IMR) cuyo cociente osciló entre 5 y 15, aproximadamente. Una alta proporción (47,6%) de enfermos refirieron no haber solicitado atención médica. Estos resultados permiten hacer estimaciones aproximadas del comportamiento real de las IRA en el universo de estudio y establecer bases para un nuevo programa de control, perfeccionando ademcis la vigilancia epidemiolóigica en la atención primaria de salud.SummaryThe present work presents the study of morbidity due to acute respiratory infections (ARI) in areas of the town of Lisa in Ciudad Habana, and Isla Juventud (Cuba), to caracterise different aspects of morbidity measured by health care attendance and to measure true morbidity. About 90% of consultations for ARI were first-time consultations, while their ratio to further consultations was 5.3. True morbidity rates (TMR), obtained trough active research, ranged from 110.4 to 163.4 cases per 1000 inhabitants, considerably higher than morbidity rates measured by primary care consultations (MRPCC) in the same time period. The true morbidity index (TMI), as measured by the ratio of the two previous rates, ranged from 5 to 15. Ahigh proportion (47.6%) of cases reported no medical careattendance. These results provide approximate estimates of true morbidity in the study area, and allow the establishment of a new control program, also improving epidemiologic surveillance within primary care activities
Compacity of soils developed over Tertiary-Quanernary sediments in the Terra Cha area (Lugo)
[Abstract] Using a gamma probe, bulk density has been measured for nine profiles from 20 cm depth to depths ranging from 90 to 15Ocm. The intent ofthis work was to assesss total porosity variability withinand between sites at an area characterized by an abrupt textural change. Bulk density values obtained at both tertiary and quaternary subsoillayers are significantly higher and show less variability between sites and also more repeteability along the time than bulk density values obtained at the surface A and B soil horizons. In addition, Hg intrusion porosimetry demonstrated a decrease of the average pore diameter with depth and thus with age of the soil and sediement materials
Ener3DMap-SolarWeb roofs: A geospatial web-based platform to compute photovoltaic potential
[EN] The effective exploitation and management of renewable energies requires knowledge not only of the energy intensity at the exploitation site but also of the influence of the geometry of the site and its surroundings. For this reason, the efficient processing and interpretation of combined geospatial and energy data is a key issue. This paper presents the development of a web-based tool for the automatic computation of photovoltaic potential on rooftops and on parcels without buildings. The tool called Ener3DMap-SolarWeb Roofs is based on Leaflet and supports WMS, GeoJSON, GeoCSV and KML formats, among others. With these data formats, base maps, geometric data from the rooftops automatically computed from LiDAR and imagery data with self-developed processing algorithms, cadastral data and a solar radiation model are integrated in the tool. These different types of data, the high level of automation and the different scales for which energy data is calculated (hourly, monthly and annually) are the main contributions of the presented tool compared to other existing solutions. The capacities of the tool are tested through its application to analyze the solar potential of rooftops with different shapes and for different solar panel configurations. The accuracy of the results is ensured through the integration of a validated methodology for the computation of geometry and a validated solar radiation model, PVGIS
Software-controlled operand-gating
Operand gating is a technique for improving processor energy efficiency by gating off sections of the data path that are unneeded by short-precision (narrow) operands. A method for implementing software-controlled power gating is proposed and evaluated. The instruction set architecture (ISA) is enhanced to include opcodes that specify operand widths (if not already included in the ISA). A compiler or a binary translator uses statically available information to determine initial value ranges. The technique is enhanced through a profile-based analysis that results in the specialization of certain code regions for a given value range. After the analysis, instruction opcodes are assigned using the minimum required width. To evaluate this technique the Alpha instruction set is enhanced to include opcodes for 8, 16, and 32 bit operands. Applying the proposed software technique to the Speclnt95 benchmarks results in energy-delay savings of 14%. When combined with previously proposed hardware-based techniques, the energy-delay benefit is 28%.Peer ReviewedPostprint (published version
Dynamic verification of mashups of service-oriented things through a mediation platform
The new Internet is evolving into the vision of the Internet of Things, where physical
world entities are integrated into virtual world things. Things are expected to become active
participants in business, information and social processes. Then, the Internet of Things could
benefit from the Web Service architecture like today’s Web does; so Future service-oriented
Internet things will offer their functionality via service-enabled interfaces. As demonstrated in
previous work, there is a need of considering the behaviour of things to develop applications in
a more rigorous way. We proposed a lightweight model for representing such behaviour based
on the service-oriented paradigm and extending the standard DPWS profile to specify the
(partial) order with which things can receive messages. To check whether a mashup of things
respects the behaviour, specified at design-time, of composed things, we proposed a static
verification. However, at run-time a thing may change its behaviour or receive requests from
instances of different mashups. Then, it is required to check and detect dynamically possible
invalid invocations provoked by the behaviour’s changes. In this work, we extend our static
verification with an approach based on mediation techniques and complex event processing to
detect and inhibit invalid invocations, checking that things only receive requests compatible
with their behaviour. The solution automatically generates the required elements to perform
run-time validation of invocations, and it may be extended to validate other issues. Here, we
have also dealt with quality of service and temporal restrictions
Short-term microbial response after laboratory heating and ground mulching adition.
Fire alters soil organic matter inducing quantitative and qualitative changes that presumably will affect post-fire soil microbial recolonisation. Several studies have evidenced marked soil organic carbon reduction after moderate and high intensity fire, which limit the total recovery of microbial biomass during years.
In order to evaluate the role of soil organic matter alteration in short-term microbial colonization process, we perform a preliminary experiment where unaltered soil from Sierra Nevada Natural Park was heated at 300 ºC during 20 minutes in a muffle furnace (H300) to simulate a medium-high intensity fire. After heating, soil samples were inoculated with unaltered fresh soil, rewetted at 55-65% of water holding capacity and incubated during 3 weeks. At the same time, unheated soil samples were incubated under the same conditions as control (UH). In addition, trying to partially alleviate soil organic matter fire-induced alterations effects on microbial colonization, we include an organic amendment treatment (M+). So, part of heated and unheated samples were amended with a mix of ground alfalfa:straw (1:1) and soil microbial abundance and activity were monitored together with soil organic matter changes.
Heating process reduces total organic carbon content. After one week of incubation carbon content in heated samples was lower than the control one, in both, amended and un-amended samples.
Microbial biomass and respiration were negatively affected by heating. Ground mulching addition increase microbial biomass and respiration but was not enough to reach control values during the whole study. Nevertheless, viable and cultivable fungi and bacteria showed different pattern. After two weeks of incubation both, fungi and bacteria were higher in heated samples. Ground mulching addition appears to stimulate fungal response in both, heated and unheated samples.
Preliminary results of this experiment evidence the transcendence of soil organic matter fire-induced changes on microbial colonization process and the importance to determine several microbial parameters to obtain a more faithful conclusion about microbial response. The organic amendment appears to alleviate partially heated-induced damage, highlighting the positive stimulation on fungal abundance in both, heated and unheated samples.This research has been funded by the Spanish Ministry of Economy and Competitiveness, through research projects POSTFIRE (CGL2013-47862-C2-1-R) and GEOFIRE (CGL2012-38655-C04-01)Peer Reviewe
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