4,130 research outputs found
Notas sobre la organería en Vizcaya durante el s. XVIII. Aportación documental
La contribución de los organeros vascos a la definitiva configuración del formato del llamado órgano ibérico es fundamental en el último tercio del siglo XVII. La documentación prueba que, a causa de su actividad constructora en esas fechas, los Órganos de Castilla empiezan a adoptar la disposición de algunos tubos de lengua en batalla, y la de otros en arcas de ecos. La tendencia en estos organeros vascos y en todos los que desde ese momento siguieron sus directrices estéticas parece ser la de disminuir los tubos colocados sobre su viento para aumentar, proporciomalmente, los tubos apostados. El tema ha sido tratado con encomiable rigor por D. Louis Jambou, que ha examinado exhaustivamente la documentación correspondiente a los instrumentos construidos en Castilla. Sin embargo, en el País Vasco no se ha realizado la investigación correspondiente que nos permitiera averiguar la causa de tan sorprendente emigración. Los organeros vascos no sólo salen del país, sino que llevan consigo dos de las tres características que el mismo Sr. Jambou considera como las distintivas y específicas del Órgano cribérico)
Age of plant influences the effect of salinity in yield and mineral content of ice plant
The use of salinity-tolerant plants represents a response to the problem of the expansion of salinized soils, making coastal and salt-affected areas productive. Furthermore, limited fresh water resources may increasingly constrain the use of low-quality irrigation water. Therefore, intensified use of halotolerant crop plants will be necessary. Mesembryanthemum crystallinum is a salinity-tolerant plant widely distributed and currently with a great gastronomic interest because is considered a functional food. The objective of this work was to evaluate the differential effect of a moderate salinity treatment imposed in ice plants of 40 or 55 days after transplanting. Thus, M. crystallinum of 40 and 55 days were grown under 0 and 100 mM NaCl during two weeks. The results showed that the effect of salinity depended of the age of plants. Growth parameters as shoot biomass or shoot height decreased in plants of 40 days after transplanting (DAT) subjected to salinity while no differences were found in 55 DAT plants. Also, salinity improved important yield parameters as leaf fresh mass and area when the treatment was applied in 55 DAT plants and caused higher SLA and chlorophylls content in both groups of plants. Ice plant can be intentionally cultivated 55 DAT under moderate salinity conditions to enhance crop yield which could contribute to a more extensive use of its edible leaves as functional and alternative food
Formation of S0 galaxies through mergers. Evolution in the Tully-Fisher relation since
(Abridged version) We explore whether a scenario that combines an origin by
mergers at 1.8-1.5 with a subsequent passive evolution of the resulting
S0 remnants since 0.8-1 is compatible with observational data of S0s in
the Tully-Fisher relation (TFR). We studied a set of major and minor merger
experiments from the GalMer database that generate massive S0 remnants. We
analysed the location of these remnants in the photometric and stellar TFRs
assuming that they correspond to galaxies. We then estimated their
evolution in these planes over the last 7 Gyr. The results were compared with
data of real S0s and spirals at different redshifts. We also tested how the use
of Vcirc or Vrot,max affects the results. We found that just after 1-2
Gyr of coalescence, major mergers generate S0 remnants that are outliers of the
local photometric and stellar TFRs at . After 4-7 Gyr of
passive evolution in isolation, the S0 remnants move towards the local TFR,
although the initial scatter among them persists. This scatter is sensitive to
the indicator used for the rotation velocity: Vcirc values yield a lower
scatter than when Vrot,max values are considered instead. In the planes
involving Vrot,max, a clear segregation of the S0 remnants in terms of the
spin-orbit coupling of the model is observed, in which the remnants of
retrograde encounters overlap with local S0s hosting counter-rotating discs.
The location of the S0 remnants at agrees well with the observed
distribution of local S0 galaxies in the -, Vcirc- and
Vrot,max- planes. Thus, massive S0 galaxies may have been formed
through major mergers that occurred at high redshift and have later evolved
towards the local TFR through passive evolution in relative isolation, a
mechanism that would also contribute to the scatter observed in this relation.Comment: 19 pages, 15 figures. Accepted for publication in A&
A single scaling parameter as a first approximation to describe the rainfall pattern of a place: application on Catalonia
As well as in other natural processes, it has been frequently observed that the phenomenon arising from the rainfall generation process presents fractal self-similarity of statistical type, and thus, rainfall series generally show scaling properties. Based on this fact, there is a methodology, simple scaling, which is used quite broadly to find or reproduce the intensity–duration–frequency curves of a place. In the present work, the relationship of the simple scaling parameter with the characteristic rainfall pattern of the area of study has been investigated. The calculation of this scaling parameter has been performed from 147 daily rainfall selected series covering the temporal period between 1883 and 2016 over the Catalonian territory (Spain) and its nearby surroundings, and a discussion about the relationship between the scaling parameter spatial distribution and rainfall pattern, as well as about trends of this scaling parameter over the past decades possibly due to climate change, has been presented.Peer ReviewedPostprint (author's final draft
Enumeration and isolation of viral particles from oligotrophic marine environments by tangential flow filtration
A method for concentrating, enumerating and isolating viral particles from marine water samples was developed and evaluated. The method consists of a concentration step by a tangential flow filtration (TFF) system, ultrafiltration by centrifugal concentrator, and visualization by transmission electron microscopy (TEM). This procedure allows to reduce volumes of ca. 2 l of seawater to 10–20 μl, which can be dispensed on electron microscopy grids to count total viral particles. This method allows the recovery of small numbers of viral particles from oligotrophic seawater samples, in which viral numbers ranged from 105 to 106 viral particles/ml. The tangential flow filtration system was evaluated as quantitative technique using suspensions of two different bacteriophages (T6 and ΦX174) in autoclaved seawater. Recovery rates varied depending on both the viral morphology and flow rate; recovery percentages reached 117.4% for T6 and 60.6% for ΦX174 using low flow rate
Antiferromagnetic behavior in S=2 layered RbMnF4
Under the terms of the Creative Commons Attribution (CC BY) license to their work.The magnetic properties of layered-perovskite RbMnF4 have been investigated by neutron powder diffraction. This compound exhibits a magnetic ordering below Tc=3.7±0.2 K. The resolution of the magnetic structure at 1.5 K indicates that RbMnF4 orders as a collinear antiferromagnet. The propagation vector is k=0 and the magnetic moment of each sublattice has a value of 2.97(3) μB. The strong reduction of the observed magnetic moment should be attributed to a particularly high two-dimensional character of this compound.The research in Zaragoza has been supported by Grant No. MAT/91-681, from the Comision Interministerial deCiencia y Tecnologia.Peer Reviewe
Analysis of extreme rainfall in Barcelona using a microscale rain gauge network
Extreme storms registered by the urban rain gauge network installed and supported by CLABSA
(Clavegueram de Barcelona S. A.) in Barcelona in the period 1994–2001 have been investigated. Eleven rain events
presenting intensities for durations between 5 min and 24 h with return periods equal to or larger than 5 years for any
of the network gauges have been found. A cluster analysis has yielded four main classes of extreme rainfall events in
this area, related to the meteorological scales involved: local (18%), mesoscale (37%) and synoptic storms (27%), as well
as more complex rain events originated by multiscale mechanisms acting together (18%). An intensity index to classify
extreme rainfall events in order to their complexity and severity, taking into account the contribution of the different scales
implied in the rainfall processes, has been calculated. The frequency distribution of the intensity index values obtained for
the urban network has resulted very similar to that calculated for rain data recorded by the Jard´ı gauge of the Observatory
Fabra of Barcelona during 1927–1992 inclusive.Postprint (published version
Sulfite-reducing clostridia in the sediment of a high mountain lake (Laguna Grande, Gredos, Spain) as indicators of fecal pollution
We studied the vertical distribution of sulfite-reducing clostridia in the sediment of a Spanish high-mountain lagoon (Laguna Grande de Gredos, central Spain), with optimal sediment characteristics (temperature < 20°C) to maintain spores without growing. This allowed us to assess the original numbers of sulfite-reducing clostridia endospores settled, without postdepositional growing. Sulfite-reducing clostridia are normal inhabitants of the intestinal microbiota of humans and other mammals. These microorganisms may form endospores, which allow the bacteria to survive in almost any habitat, either terrestrial or aquatic, waiting for favorable conditions for growth. Sulfite-reducing clostridia could be suitable indicators of past human pollution because they have a great longevity in natural habitats and they cannot multiply at temperatures below 20°C or in the presence of O2. We found a great increase in the numbers of clostridia (expressed as colony-forming units per gram [CFU/g] of dry weight of sediment) since the 1970s, which reflects the rise of human pressure caused by the practice of outdoor activities.Clostridia CFU/g rose dramatically after the faulty operation of the depuration system of a mountain refuge built close to the lagoon. We compared the vertical distribution of clostridia CFU/g from Laguna Grande sediments with those from a neighbor lagoon (Laguna Cimera), which showed less tourist pressure and no direct disposal of sewage. Finally, we agree with the usefulness of the numbers of sulfitereducing clostridia as indicators of past pollution
Quality control process of the daily rainfall series available in Catalonia from 1855 to the present
The quality control of weather data is a necessity and a responsibility of meteorological services that store, distribute, and use these data. In the present work, a newly designed quality control procedure for daily rainfall data is presented after it has been adjusted and tested with more than 10^7 data from 1726 daily rainfall measurement sites in Catalonia. It is applicable to data from different origins (e.g., automatic weather stations or manual historical measurements). The procedure is focused on relative comparison of daily data with reference stations that are automatically selected after an initial estimation of their quality and a proximity study regarding location and correlation. The presented procedure has been verified taking advantage of an available network in the study area that has been routinely quality controlled by technicians of the Meteorological Service of Catalonia. The newly designed quality control procedure for daily precipitation yields good results, especially for extreme values: type I error under 10% is found for values up to 150 mm (error decreasing for lower values) and type II error is under 16% when reported values are twice a measure of 50 mm or more (error decreasing for more extreme values). After the application of the quality control procedure, a selection of series with the minimum desired quality is achieved.Peer ReviewedPostprint (author's final draft
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