3,335 research outputs found
Socialization of the elderly in outdoor health circuits
En los parques biosaludables, originalmente concebidos para la población madura y anciana, se encuentran usuarios de diferentes edades y con distintas formas de entender la actividad fÃsica. El presente trabajo intenta examinar las relaciones de las personas mayores con el resto de usuarios para determinar en qué medida dichos parques pueden cumplir alguna función social más allá del fomento de hábitos saludables. Para ello se ha llevado a cabo una serie de observaciones, participantes y no participantes, en tres parques de la ciudad de Granada, donde se ha visto que, si bien existe una proporción minoritaria pero importante de usuarios jóvenes (aproximadamente un tercio del total), estos tienden a evitar una interacción que parte de los usuarios de mayor edad buscan expresamente
Floral morphology and development in Aragoa (Plantaginaceae) and related members of the order Lamiales
Inflorescence and floral morphology and development were investigated in Aragoa (Plantaginaceae) and
related genera. Each inflorescence of Aragoa is a reduced, axillary raceme, on which the actinomorphic floral
apices generally arise successively. The inflorescences of Aragoa and Plantago are polytelic and lateral. The five
sepals emerge from the abaxial to the adaxial side of the floral apex, but at maturity, the calyx is
actinomorphic. The four stamens arise simultaneously and before emergence of the petals. The four petals
emerge unidirectionally united, but the corolla becomes actinomorphic. Aestivation is cochlear ascendent. The
two united carpels initiate simultaneously. The abaxial-adaxial inception of the calyx and corolla during early
floral development in genera such as Aragoa, Digitalis, Plantago, and Veronica may indicate that the
zygomorphic condition is ancestral in those genera. The tetramerous corolla, which is actinomorphic during
middle and late development, and the presence of four stamens are possible synapomophies of the clade
(Aragoa þ Plantago). Pentamery of the calyx and corolla appears to be plesiomorphic in the broader Aragoa-
Angelonia clade. Characters related to development and morphology of inflorescences and flowers of Aragoa
are essentially similar to those found in Plantago, which is consistent with the molecular-based sister group
relationship between these genera.Peer reviewe
Possible ring material around centaur (2060) Chiron
We propose that several short duration events observed in past stellar
occultations by Chiron were produced by rings material. From a reanalysis of
the stellar occultation data in the literature we determined two possible
orientations of the pole of Chiron's rings, with ecliptic coordinates
l=(352+/-10) deg, b=(37+/-10) deg or l=(144+/-10) deg, b=(24+/-10) deg . The
mean radius of the rings is (324 +/- 10) km. One can use the rotational
lightcurve amplitude of Chiron at different epochs to distinguish between the
two solutions for the pole. Both imply lower lightcurve amplitude in 2013 than
in 1988, when the rotational lightcurve was first determined. We derived
Chiron's rotational lightcurve in 2013 from observations at the 1.23-m CAHA
telescope and indeed its amplitude is smaller than in 1988. We also present a
rotational lightcurve in 2000 from images taken at CASLEO 2.15-m telescope that
is consistent with our predictions. Out of the two poles the l=(144+/-10) deg,
b=(24+/-10) deg solution provides a better match to a compilation of rotational
lightcurve amplitudes from the literature and those presented here. We also
show that using this preferred pole, Chiron's long term brightness variations
are compatible with a simple model that incorporates the changing brightness of
the rings as the tilt angle with respect to the Earth changes with time. Also,
the variability of the water ice band in Chiron's spectra in the literature can
be explained to a large degree by an icy ring system whose tilt angle changes
with time and whose composition includes water ice, analogously to the case of
Chariklo. We present several possible formation scenarios for the rings from
qualitative points of view and speculate on the reasons why rings might be
common in centaurs. We speculate on whether the known bimodal color
distribution of centaurs could be due to presence of rings and lack of them
Estudio comparativo de la influencia de las fibras en la retracción de los morteros reciclados
Construction and demolition waste can be used as a substitution of natural aggregate in mortar and concrete elaboration. A poorer quality of recycled aggregates generally has negative impact on mortar properties. Shrinkage is one of the properties that experiences worse outcome due to the higher absorption of recycled aggregates. This research evaluates the potential shrinkage of mortars elaborated with recycled concrete aggregates both with and without fibres addition, as well as the relation between moisture loss and shrinkage caused by mortar drying process using a capacitive sensor of the authors’ own design. Two different mortar dosages 1:3 and 1:4 and three fiber types: polypropylene fiber, fiberglass and steel fiber, in different proportions were used. Obtained results show that the use of polypropylene fiber improves the recycled mortars performance against shrinkage in 0.2%. Moreover, a clear relation between dry shrinkage and moisture loss was observed.Los Residuos de Construcción y Demolición pueden ser usados como sustitución de los áridos naturales en la fabricación de morteros y hormigones. La peor calidad de los áridos reciclados empeora de manera general las propiedades de los morteros, siendo la retracción una de las que más se ve afectada. Esta investigación, estudia la retracción de los morteros elaborados con arena reciclada de hormigón con y sin adicción de fibras, asà como la relación existente entre la perdida de humedad y la retracción por secado mediante un sensor capacitivo de diseño propio. Se han empleado dos dosificaciones diferentes 1:3 y 1:4 y tres tipos de fibras: polipropileno, vidrio y acero, en distintas proporciones. Los resultados muestran que la adición de fibras de polipropileno en un 0,2% mejora significativamente la retracción en los morteros reciclados. Además, se ha obtenido una relación clara entre la retracción por secado y la perdida de humedad
Phase diagram and influence of defects in the double perovskites
The phase diagram of the double perovskites of the type Sr_{2-x} La_x Fe Mo
O_6 is analyzed, with and without disorder due to antisites. In addition to an
homogeneous half metallic ferrimagnetic phase in the absence of doping and
disorder, we find antiferromagnetic phases at large dopings, and other
ferrimagnetic phases with lower saturation magnetization, in the presence of
disorder.Comment: 4 pages, 3 postscript figures, some errata correcte
Is trivial the antiferromagnetic RP(2) model in four dimensions?
We study the antiferromagnetic RP(2) model in four dimensions. We find a
second order transition with two order parameters, one ferromagnetic and the
other antiferromagnetic. The antiferromagnetic sector has mean-field critical
exponents and a renormalized coupling which goes to zero in the continuum
limit. The exponents of the ferromagnetic channel are not the mean-field ones,
but the difference can be interpreted as logarithmic corrections. We perform a
detailed analysis of these corrections and conclude the triviality of the
continuum limit of this model.Comment: 21 pages, 5 figures, LaTeX2
Self-sustained enzymatic cascade for the production of 2, 5-furandicarboxylic acid from 5-methoxymethylfurfural
Background: 2, 5-Furandicarboxylic acid is a renewable building block for the production of polyfurandicarboxylates, which are biodegradable polyesters expected to substitute their classical counterparts derived from fossil resources. It may be produced from bio-based 5-hydroxymethylfurfural or 5-methoxymethylfurfural, both obtained by the acidic dehydration of biomass-derived fructose. 5-Methoxymethylfurfural, which is produced in the presence of methanol, generates less by-products and exhibits better storage stability than 5-hydroxymethylfurfural being, therefore, the industrial substrate of choice.
Results: In this work, an enzymatic cascade involving three fungal oxidoreductases has been developed for the production of 2, 5-furandicarboxylic acid from 5-methoxymethylfurfural. Aryl-alcohol oxidase and unspecific peroxygenase act on 5-methoxymethylfurfural and its partially oxidized derivatives yielding 2, 5-furandicarboxylic acid, as well as methanol as a by-product. Methanol oxidase takes advantage of the methanol released for in situ producing H2O2 that, along with that produced by aryl-alcohol oxidase, fuels the peroxygenase reactions. In this way, the enzymatic cascade proceeds independently, with the only input of atmospheric O2, to attain a 70% conversion of initial 5-methoxymethylfurfural. The addition of some exogenous methanol to the reaction further improves the yield to attain an almost complete conversion of 5-methoxymethylfurfural into 2, 5-furandicarboxylic acid.
Conclusions: The synergistic action of aryl-alcohol oxidase and unspecific peroxygenase in the presence of 5-methoxymethylfurfural and O2 is sufficient for the production of 2, 5-furandicarboxylic acid. The addition of methanol oxidase to the enzymatic cascade increases the 2, 5-furandicarboxylic acid yields by oxidizing a reaction by-product to fuel the peroxygenase reactions
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