427 research outputs found
Sustainable urban pavement for cities affected by El Niño using porous concrete
The El Niño phenomenon is caused by the change in atmospheric pressures, which produce the accumulation of hot surface waters on the eastern flank of the Pacific Ocean; causing intense rainfall that runs over the surface affecting the urban drainage of the city due to the lack of a permeable pavement; porous concrete allows infiltration of surface water runoff through its pores. The present investigation evaluates porous concrete in the range of w/c relationships of 0.30 and 0.32; the results indicate that the compressive strength, flexural strength and permeability coefficient increase; and that the surface runoff, cost, water footprint and carbon footprint are lower than conventional concrete
Testing the asymptotic relation for period spacings from mixed modes of red giants observed with the Kepler mission
Dipole mixed pulsation modes of consecutive radial order have been detected
for thousands of low-mass red-giant stars with the NASA space telescope Kepler.
Such modes have the potential to reveal information on the physics of the deep
stellar interior. Different methods have been proposed to derive an observed
value for the gravity-mode period spacing, the most prominent one relying on a
relation derived from asymptotic pulsation theory applied to the gravity-mode
character of the mixed modes. Our aim is to compare results based on this
asymptotic relation with those derived from an empirical approach for three
pulsating red-giant stars. We developed a data-driven method to perform
frequency extraction and mode identification. Next, we used the identified
dipole mixed modes to determine the gravity-mode period spacing by means of an
empirical method and by means of the asymptotic relation. In our methodology,
we consider the phase offset, , of the asymptotic
relation as a free parameter. Using the frequencies of the identified dipole
mixed modes for each star in the sample, we derived a value for the
gravity-mode period spacing using the two different methods. These differ by
less than 5%. The average precision we achieved for the period spacing derived
from the asymptotic relation is better than 1%, while that of our data-driven
approach is 3%. Good agreement is found between values for the period spacing
derived from the asymptotic relation and from the empirical method.
Full abstract in PDF file.Comment: 14 pages, 13 figures, accepted for publication in A&
IgG Subclass and the FcG Receptor Iia Polymorphism Associate to Dengue Fever, Dengue Hemorrhagic Fever and Asymptomatic Dengue Infection in Cuba
A preliminary study of the fisheries canane (Ocyurus chrysurus) in Holbox, Quintana Roo, Mexico [abstract]; Estudio preliminar de la pesqueria de canane (Ocyurus chrysurus) en Holbox, Quintana Roo, Mexico [resumen]
A thorough investigation of the switching dynamics of TiN/Ti/10Â nm-HfO2/W resistive memories
ProducciĂłn CientĂficaThe switching dynamics of TiN/Ti/HfO2/W-based resistive memories is investigated. The analysis consisted in the systematic application of voltage sweeps with different ramp rates and temperatures. The obtained results give clear insight into the role played by transient and thermal effects on the device operation. Both kinetic Monte Carlo simulations and a compact modeling approach based on the Dynamic Memdiode Model are considered in this work with the aim of assessing, in terms of their respective scopes, the nature of the physical processes that characterize the formation and rupture of the filamentary conducting channel spanning the oxide film. As a result of this study, a better understanding of the different facets of the resistive switching dynamics is achieved. It is shown that the temperature and, mainly, the applied electric field, control the switching mechanism of our devices. The Dynamic Memdiode Model, being a behavioral analytic approach, is shown to be particularly suitable for reproducing the conduction characteristics of our devices using a single set of parameters for the different operation regimes.Ministerio de Ciencia e InnovaciĂłn de España - FEDER [PID2022-139586NB-C41, PID2022-139586NB-C42, PID2022-139586NB-C43, PID2022-139586NB-C44]ConsejerĂa de Conocimiento, InvestigaciĂłn y Universidad, Junta de AndalucĂa [B-TIC-624-UGR20]Consejo Superior de Investigaciones CientĂficas (CSIC)- FEDER [20225AT012]RamĂłn y Cajal grant number RYC2020-030150-IEuropean project MEMQuD (code 20FUN06) which has received funding from the EMPIR programme co-financed by the Participating States and from the European Union's Horizon 2020 research and innovation programme
Paleoseismic Evidence of an Mw 7 Pre-Hispanic Earthquake in the Peruvian Forearc
We present the results of a paleoseismic survey of the Incapuquio Fault System, a prominent transpressional fault system cutting the forearc of South PerĂș. High-resolution Digital Elevation Models, optical satellite imagery, radiocarbon dating, and paleoseismic trenching indicate that at least 2â3 m of net slip occurred on the Incapuquio Fault generating a complex, âŒ100-km long set of segmented fault scarps in the early 15th century (âŒ1400â1440 CE). We interpret the consistent along-strike pattern of fault scarp heights, geometries and kinematics to reflect a surface rupture generated by a single Mw 7.4â7.7 earthquake, suggesting that brittle failure of the forearc poses a significant, yet mostly overlooked, seismic hazard to the communities in coastal areas of PerĂș. The timing of this earthquake coincides with the collapse of the Chiribaya civilization in âŒ1360â1400 CE, and we present evidence of damaged buildings along the fault trace that may be of Chiribayas age. Our surface faulting observations, when combined with observations of deformation in the forearc from geodesy and seismology, also demonstrate that the forearc in South PerĂș experiences a complex, time-varying pattern of permanent strain, with evidence for trench-parallel shortening, trench-parallel extension, and trench-perpendicular shortening all in close proximity but in different periods of the megathrust earthquake cycle. The kinematics of recent slip on the Incapuquio Fault are consistent with the sense of interseismic strain within the forearc measured by GPS, suggesting the fault is loaded toward failure between megathrust earthquakes
Verifying asteroseismically determined parameters of Kepler stars using hipparcos parallaxes: self-consistent stellar properties and distances
Accurately determining the properties of stars is of prime importance for
characterizing stellar populations in our Galaxy. The field of asteroseismology
has been thought to be particularly successful in such an endeavor for stars in
different evolutionary stages. However, to fully exploit its potential, robust
methods for estimating stellar parameters are required and independent
verification of the results is mandatory. With this purpose, we present a new
technique to obtain stellar properties by coupling asteroseismic analysis with
the InfraRed Flux Method. By using two global seismic observables and
multi-band photometry, the technique allows us to obtain masses, radii,
effective temperatures, bolometric fluxes, and hence distances for field stars
in a self-consistent manner. We apply our method to 22 solar-like oscillators
in the Kepler short-cadence sample, that have accurate Hipparcos parallaxes.
Our distance determinations agree to better than 5%, while measurements of
spectroscopic effective temperatures and interferometric radii also validate
our results. We briefly discuss the potential of our technique for stellar
population analysis and models of Galactic Chemical Evolution.Comment: 28 pages, 5 figures, ApJ, accepte
Behaviour of uranium along Jucar River (Eastern Spain) Determination of 234U/238U and 235U/238U ratios
The uranium concentration and the U-234/U-238, U-235/U-238 activity ratios were studied in water samples from Jucar River, using low-level alpha-spectrometry. The effects of pH, temperature and salinity were considered and more detailed sampling was done in the neighbourhood of Cofrentes Nuclear plant (Valencia, Spain). Changes were observed in the uranium concentration with the salinity and the U-234/U-238 activity ratio was found to vary with pH. Leaching and dilution, which depend on pH and salinity, are the probable mechanisms for these changes in the concentration of uranium and the activity ratios.RodrĂguez Ălvarez, MJ.; Sanchez, F. (1995). Behaviour of uranium along Jucar River (Eastern Spain) Determination of 234U/238U and 235U/238U ratios. Journal of Radioanalytical and Nuclear Chemistry. 190(1):113-120. doi:10.1007/BF02035642S1131201901M. J. RORDĂGUEZ-AALVAREZ, F. SĂNCHEZ, E. NAVARRO, Proc. 3nd Intern. Summer School, Huelva Spain, M. GARCĂA-LEĂN, G. MADURGA (Eds), World Scientific, Singapore, 1994.M. IVANOVICH, R. S. HARMON (Eds), Uranium Disequilibrium Series: Applications to Environmental Problems, Clarendon Press, Oxford, 1982.K. OSMOND, J. B. COWART, At. Energy Rev., 14 (1976) 621.B. L. DICKSON, R. L. MEAKINS, Nucl. Instrum. Methods Phys. Res., 223 (1983) 593.J. L. GASCĂN, MURILLO, PhD Thesis, University of Zaragoza, Spain, 1990.M. C. MORĂN, A. MARTINEZ-AGUIRRE, M. GARCĂA-LEĂN, Intern. Conf. on Environmental Radioactivity in the Mediterranean Area, Barcelona 10â13 May 1988, SNE-ENS, Barcelona, 1988, p. 111.R. BOJANOWSKI, R. FUKAI, S. BALLESTRA, H. ASARI, Determination of natural radioactive elements in marine environmental materials by ion-exchange and α-spectrometry. Proc. 4th Symp. on the Determination of Radionuclides in Environmental and Biological Materials, April 1983, London, Ed-Rd Press.R. GARCĂA-TENORIO, M. GARCĂA-LEĂN, G. PIAZZA, Anal. FĂsica B, 82 (1986) 238.L. HALLSTADIUS, Nucl. Instrum. Methods Phys. Res., 223 (1984) 266.F. VERA, A. MARTIN, Nucl. Instrum. Methods Phys. Res., A276 (1989) 289.A. MARTINEZ-AGUIRRE, M. GARCĂA-LEĂN, J. Radioanal. Nucl. Chem., 155 (1991) 97.J. R. DOOLEY, H. C. ROSHOLT, Econ. Geol., 61 (1996) 326.A. MARTINEZ-AGUIRRE, M. GARCĂA-LEĂN, Radiat. Prot. Dosim., 45 (1992) 249.J. TOOLE, M. S. BAXTER, J. THOMSON, Estuarine, Coastal and Shelf Sci., 25 (1987) 283.S. G. BHAT, S. KRISHANASWAMI, Proc. Indian Acad. Sci., A LXX, (1969).K. K. TUREKIAN, J. K. COCHRAN, in: Chemical Oceanography, Vol. 7, J. P. RILEY and R. CHESTER (Eds), 2nd ed., Academic Press, New York, 1978.D. LANGMUIR, Geochim. Cosmochim. Acta, 42 (1978) 547.J. M. MARTIN, M. MEYBECK, Mar. Chem., 7 (1979) 173.Radionuclide Transformations, Annals of the ICRP, ICRP Publication 38, Vol. 11â13, Pergamon Press, 1983.A. MANGINI, G. SONNTAG, G. BERTSCH, E. MĂLLER, Nature, 278 (1979) 337.M. R. SCOTT, in: M. IVANOVICH, R. S. HARMON (Eds), Uranium Disequilibrium Series: Applications to Environmental Problems, Clarendon Press, Oxford, 1982.J. K. OSMOND, J. B. COWART, in: M. IVANOVICH, R. S. HARMON (Eds), Uranium Disequilibrium Series: Applications to Environmental Problems, Clarendon Press, Oxford, 1982.R. BOWEN (Eds), Isotopes in the Earth Sciences, Elsevier Applied Science, 1988.F. VERA, PhD Thesis, University Extremadura, Spain, 1988.F. VERA, A. MARTIN, J. Radioanal. Nucl. Chem., 134 (1988) 73
The molecular basis and biologic significance of the ÎČ-dystroglycan-emerin interaction
ÎČ-dystroglycan (ÎČ-DG) assembles with lamins A/C and B1 and emerin at the nuclear envelope (NE) to maintain proper nuclear architecture and function. To provide insight into the nuclear function of ÎČ-DG, we characterized the interaction between ÎČ-DG and emerin at the molecular level. Emerin is a major NE protein that regulates multiple nuclear processes and whose deficiency results in EmeryâDreifuss muscular dystrophy (EDMD). Using truncated variants of ÎČ-DG and emerin, via a series of in vitro and in vivo binding experiments and a tailored computational analysis, we determined that the ÎČ-DGâemerin interaction is mediated at least in part by their respective transmembrane domains (TM). Using surface plasmon resonance assays we showed that emerin binds to ÎČ-DG with high affinity (KD in the nanomolar range). Remarkably, the analysis of cells in which DG was knocked out demonstrated that loss of ÎČ-DG resulted in a decreased emerin stability and impairment of emerin-mediated processes. ÎČ-DG and emerin are reciprocally required for their optimal targeting within the NE, as shown by immunofluorescence, western blotting and immunoprecipitation assays using emerin variants with mutations in the TM domain and B-lymphocytes of a patient with EDMD. In summary, we demonstrated that ÎČ-DG plays a role as an emerin interacting partner modulating its stability and function
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