Field experimental study of traffic-induced turbulence on highways

This paper is focused on traffic-induced turbulence (TIT) analysis from a field campaign performed in 2011, using ultrasonic anemometers deployed in the M-12 Highways, Madrid (Spain). The study attempts to improve knowledge about the influence of traffic-related parameters on turbulence. Linear relationships between vehicle speed and turbulent kinetic energy (TKE) values are found with coefficients of determination (R2) of 0.75 and 0.55 for the lorry and van respectively. The vehicle-induced fluctuations in the wind components (u', v' and w') showed the highest values for the longitudinal component (v) because of the wake-passing effect. In the analysis of wake produced by moving vehicles it is indicated how the turbulence dissipates in relation to a distance d and height h. The TKE values were found to be higher at the measuring points closer to the surface during the wake analysis.This work was supported by the OASIS Research Project that was co financed by CDTI (Spanish Science and Innovation Ministry) and developed with the Spanish companies: Iridium, OHL Concesiones, Abertis, Sice, Indra, Dragados, OHL, Geocisa, GMV, Asfaltos Augusta, Hidrofersa, Eipsa, PyG, CPS, AEC and Torre de Comares Arquitectos s.l and 16 research centres

Probing O-enrichment in C-rich dust planetary nebulae

The abundance of O in planetary nebulae (PNe) has been historically used as a metallicity indicator of the interstellar medium (ISM) where they originated; e.g., it has been widely used to study metallicity gradients in our Galaxy and beyond. However, clear observational evidence for O self enrichment in low-metallicity Galactic PNe with C-rich dust has been recently reported. Here we report asymptotic giant branch (AGB) nucleosynthesis predictions for the abundances of the CNO elements and helium in the metallicity range Zsun/4 < Z < 2Zsun. Our AGB models, with diffusive overshooting from all the convective borders, predict that O is overproduced in low-Z low-mass (~1-3 Msun) AGB stars and nicely reproduce the recent O overabundances observed in C-rich dust PNe. This confirms that O is not always a good proxy of the original ISM metallicity and another chemical elements such as Cl or Ar should be used instead. The production of oxygen by low-mass stars should be thus considered in galactic-evolution models.Comment: Accepted for publication in MNRAS Letters (5 pages, 1 figure, and 1 table

Galactic planetary nebulae with precise nebular abundances as a tool to understand the evolution of asymptotic giant branch stars

We present nucleosynthesis predictions (HeCNOCl) from asymptotic giant branch (AGB) models, with diffusive overshooting from all the convective borders, in the metallicity range Z/4 < Z < 2Zsun. They are compared to recent precise nebular abundances in a sample of Galactic planetary nebulae (PNe) that is divided among double-dust chemistry (DC) and oxygen-dust chemistry (OC) according to the infrared dust features. Unlike the similar subsample of Galactic carbon-dust chemistry PNe recently analysed by us, here the individual abundance errors, the higher metallicity spread, and the uncertain dust types/subtypes in some PNe do not allow a clear determination of the AGB progenitor masses (and formation epochs) for both PNe samples; the comparison is thus more focussed on a object-by-object basis. The lowest metallicity OC PNe evolve from low-mass (~1 Msun) O-rich AGBs, while the higher metallicity ones (all with uncertain dust classifications) display a chemical pattern similar to the DC PNe. In agreement with recent literature, the DC PNe mostly descend from high-mass (M > 3.5 Msun) solar/supersolar metallicity AGBs that experience hot bottom burning (HBB), but other formation channels in low-mass AGBs like extra mixing, stellar rotation, binary interaction, or He pre-enrichment cannot be disregarded until more accurate C/O ratios would be obtained. Two objects among the DC PNe show the imprint of advanced CNO processing and deep second dredge-up, suggesting progenitors masses close to the limit to evolve as core collapse supernovae (above 6 Msun). Their actual C/O ratio, if confirmed, indicate contamination from the third dredge-up, rejecting the hypothesis that the chemical composition of such high-metallicity massive AGBs is modified exclusively by HBB.Comment: Accepted for publication in MNRAS (11 pages, 3 figures, and 2 tables

The anatomy of urban social networks and its implications in the searchability problem

The appearance of large geolocated communication datasets has recently increased our understanding of how social networks relate to their physical space. However, many recurrently reported properties, such as the spatial clustering of network communities, have not yet been systematically tested at different scales. In this work we analyze the social network structure of over 25 million phone users from three countries at three different scales: country, provinces and cities. We consistently find that this last urban scenario presents significant differences to common knowledge about social networks. First, the emergence of a giant component in the network seems to be controlled by whether or not the network spans over the entire urban border, almost independently of the population or geographic extension of the city. Second, urban communities are much less geographically clustered than expected. These two findings shed new light on the widely-studied searchability in self-organized networks. By exhaustive simulation of decentralized search strategies we conclude that urban networks are searchable not through geographical proximity as their country-wide counterparts, but through an homophily-driven community structure

Hot bottom burning and s-process nucleosynthesis in massive AGB stars at the beginning of the thermally-pulsing phase

We report the first spectroscopic identification of massive Galactic asymptotic giant branch (AGB) stars at the beginning of the thermal pulse (TP) phase. These stars are the most Li-rich massive AGBs found to date, super Li-rich AGBs with logE(Li)~3-4. The high Li overabundances are accompanied by weak or no s-process element (i.e. Rb and Zr) enhancements. A comparison of our observations with the most recent hot bottom burning (HBB) and s-process nucleosynthesis models confirms that HBB is strongly activated during the first TPs but the 22Ne neutron source needs many more TP and third dredge-up episodes to produce enough Rb at the stellar surface. We also show that the short-lived element Tc, usually used as an indicator of AGB genuineness, is not detected in massive AGBs which is in agreement with the theoretical predictions when the 22Ne neutron source dominates the s-process nucleosynthesis.Comment: Accepted for publication in Astronomy & Astrophysics Letters (7 pages, 5 figures and 1 table); final version (language corrected

Physical activity and smoking habit in adolescent students

El objetivo de este estudio fue detectar en qué medida afecta la actividad física y el hábito tabáquico en estudiantes de Enseñanza Secundaria. Se estudiaron 168 adolescentes no fumadores y fumadores recién iniciados. Se midieron peso, talla, presión arterial, frecuencia cardíaca, actividad física, fuerza, flexibilidad y resistencia y una prueba espirométrica. Tanto en chicas y chicos fumadores, se evidenciaron peores resultados en la mayoría de los parámetros espirométricos (FEV1, FEF25-75%, FVC) y un envejecimiento prematuro del pulmón, más acentuado en chicas. La actividad físico-deportiva moderada se asocia a adolescentes que menos fuman y tienen más facilidad para abandonar el hábito tabáquicoThe aim of the study was to detect how physical education and smoking habits affect secondary school students, 168 non smokers and newly initiated were studied. Weight, height, heart rate, blood pressure, physical activity, strength, flexibility and endurance, and spirometric tests were analyzed. In both, female and male smokers, obtained worse results in the mayority of spirometric parameters (FEV1, FEF25-75%, FVC) and premature lung ageing, more pointed in females. Moderate physical-sporting activity is associated to adolescents who smoke less and quit smoking more easil

Nueva forma de entender las pruebas de condición física en relación con la salud

El objetivo de este trabajo es mostrar una nueva forma de entender la evaluación de la “condición física en relación con la salud”, para evitar la inactividad y el sedentarismo. Los antecedentes se encuentran en las baterías de test utilizadas desde 1976 hasta la actualidad. Se utiliza el concepto de salud de la OMS. Se analizan pruebas con criterios de funcionalidad, economía, validez, fiabilidad y especificidad. Se eligen las siguientes pruebas y se calculan los umbrales: UKK Walk test (P75), 6” en sprint test 20 m (P75), 19 repeticiones en Chair Stand Test(P25), 11 repeticiones Arm Curl Test (P25), -10,5 cm Back Scratch Test (P25), -17,5 cm en Chair Sit and Reach Test. Se propugna la elaboración de una batería de test universal e inclusiva y elaborar percentiles mundiales ayudados por el big dataThe aim of this research was to propose a new way of understanding health-related physical fitness assessment in order to prevent inactivity and sedentarism. The background lies in the test batteries used from 1976 to the present. WHO's health concept was used. Tests were analysed based on functionality, economy, validity, reliability and specificity criteria. The following tests were chosen and the thresholds were calculated: 1,425s in the UKK walk test (P75), 6s in the 20-m sprint test (P75), 19 repetitions in the chair stand test (P25), 11 repetitions in the arm curl test (P25), -10.5cm in the back scratch test (P25), -17.5cm in the chair sit-and-reach test (P25). It was proposed that a universal and inclusive test battery be developed and the percentiles for the world population are determined with the help of big dat

The short-term debt choice under asymmetric information

This paper investigates whether the market level of information asymmetry affects firms’ debt financing decisions. Using a sample of non-financial listed firms and a composite index based on microstructure measures of information asymmetry, we find that firms with more information asymmetry use shorter debt maturities. In addition, we find that these firms face more difficulties to access public debt and bank debt (particularly, short-term bank debt), and they have to rely on trade credit as an alternative source of short-term financing. Analyzing the associations in two subsamples based on firm size, we find that our results essentially driven by smaller companies, which are those affected by higher information asymmetries. Our findings support the information asymmetry theories of trade credit: as information asymmetry increases and, consequently, listed firms face more constraints in the credit markets, they increase the use of financing provided by their suppliers.David Abad acknowledges financial support from the Ministerio de Economía y Competitividad through Grants ECO2013-4409-P and ECO2014-58434-P. José Yagüe acknowledges financial support from Fundación Caja Murcia