An approach to identify urban groundwater recharge

Evaluating the proportion in which waters from different origins are mixed in a given water sample is relevant for many hydrogeological problems, such as quantifying total recharge, assessing groundwater pollution risks, or managing water resources. Our work is motivated by urban hydrogeology, where waters with different chemical signature can be identified (losses from water supply and sewage networks, infiltration from surface runoff and other water bodies, lateral aquifers inflows, ...). The relative contribution of different sources to total recharge can be quantified by means of solute mass balances, but application is hindered by the large number of potential origins. Hence, the need to incorporate data from a large number of conservative species, the uncertainty in sources concentrations and measurement errors. We present a methodology to compute mixing ratios and end-members composition, which consists of (i) Identification of potential recharge sources, (ii) Selection of tracers, (iii) Characterization of the hydrochemical composition of potential recharge sources and mixed water samples, and (iv) Computation of mixing ratios and reevaluation of end-members. The analysis performed in a data set from samples of the Barcelona city aquifers suggests that the main contributors to total recharge are the water supply network losses (22%), the sewage network losses (30%), rainfall, concentrated in the non-urbanized areas (17%), from runoff infiltration (20%), and the Besòs River (11%). Regarding species, halogens (chloride, fluoride and bromide), sulfate, total nitrogen, and stable isotopes (<sup>18</sup>O, <sup>2</sup>H, and <sup>34</sup>S) behaved quite conservatively. Boron, residual alkalinity, EDTA and Zn did not. Yet, including these species in the computations did not affect significantly the proportion estimations

Improving the functional properties of (K0.5Na0.5)NbO3 piezoceramics by acceptor doping

ZrO2 and TiO2 modified lead-free (K0.5Na0.5)NbO3 (KNN) piezoelectric ceramics are prepared by conventional solid-state reaction. The effect of acceptor doping on structural and functional properties are investigated. A decrease in the Curie temperature and an increase in the dielectric constant values are observed when doping. More interestingly, an increase in the coercive field Ec and remanent polarization Pr is observed. The piezoelectric properties are greatly increased when doping with small concentrations dopants. ZrO2 doped ceramic exhibits good piezoelectric properties with piezoelectric coefficient d33=134 pC/N and electromechanical coupling factor kp=35%. It is verified that nonlinearity is significantly reduced. Thus, the creation of complex defects capable of pinning the domain wall motion is enhanced with doping, probably due to by the formation of oxygen vacancies. These results strongly suggest that compositional engineering using low concentrations of acceptor doping is a good means of improving the functional properties of KNN lead-free piezoceramic system

Muscle characteristics and maximal/explosive force production during isometric/dynamic actions of leg extensor muscles in untrained young men

Participaron en el estudio, de forma voluntaria cinco sujetos de sexo masculino, estudiantes de educación Física (22-26 años). El objetivo fue observar las relaciones entre el test de salto horizontal con los tests de salto vertical con contramovimiento y con flexión previa, tests de fuerza isométrica máxima y la distribución de los tipos de fibras musculares. Los resultados en la distancia y altura de vuelo conseguidas en los tests de salto horizontal, salto desde flexión previa sin contramovimiento y salto con contramovimiento fueron respectivamente 2,53 m ± 0,17, 0,32 m ± 0,05 y 0,40 m ± 0,05. No se encontraron correlaciones significativas entre las fibras tipo I, tipo IIA y tipo IIB y los tests realizados. Tampoco se encontraron correlaciones significativas entre la máxima fuerza, la pendiente de fuerza isométrica y entre la distancia y alturas de salto. Por otro lado, tampoco se encontraron correlaciones entre la fuerza y la potencia en el salto horizontal (2,53 B W ± 0,17 y 63,4 W/kg ± 5,4, respectivamente) y la distancia lograda. El test de fuerza isométrica máxima se realizó con dos diferentes ángulos de flexión de rodillas: 90" y 120". Tanto el pico de máxima fuerza isométrica como la máxima pendiente de desarrollo de la fuerza fueron superiores al realizar el test con una flexión de rodillas de 120" (2268 N ± 576 y 8962 N/s ± 1945 frente a 1538 N ± 300 y 7398 N/s ± 1557 con 90" de flexión). Por último, no se encontraron relaciones significativas entre la fuerza isométrica máxima y la fuerza explosiva en acciones dinámicas

The Composition Gradient in M101 Revisited. II. Electron Temperatures and Implications for the Nebular Abundance Scale

(Abridged) We use high S/N spectra of 20 HII regions in the giant spiral galaxy M101 to derive electron temperatures for the HII regions and robust metal abundances over radii R = 0.19-1.25 Ro (6-41 kpc). We compare the consistency of electron temperatures measured from the [O III]4363, [N II]5755, [S III]6312, and [O II]7325 auroral lines. Temperatures from [O III], [S III], and [N II] are correlated with relative offsets that are consistent with expectations from nebular photoionization models. However, the temperatures derived from the [O II]7325 line show a large scatter and are nearly uncorrelated with temperatures derived from other ions. Our derived oxygen abundances O/H are well fitted by an exponential distribution over six disk scale lengths, from approximately 1.3 solar in the center to 1/15 solar in the outermost region studied (for solar 12 + log (O/H)=8.7). We measure significant radial gradients in N/O and He/H abundance ratios, but relatively constant S/O and Ar/O. Our abundances are systematically lower by 0.2-0.5 dex than those derived from the most widely used strong-line "empirical" abundance indicators. We suspect that most of the disagreement with the strong-line abundances arises from uncertainties in the nebular models that are used to calibrate the "empirical" scale, and that strong-line abundances derived for HII regions and emission-line galaxies are as much as a factor of two higher than the actual oxygen abundances. However other explanations, such as the effects of temperature fluctuations on the auroral line based abundances cannot be completely ruled out. These results point to the need for direct abundance determinations of a larger sample of extragalactic HII regions, especially for objects more metal-rich than solar.Comment: 50 pages, 14 figures, 8 tables. Accepted by Ap

Identification of the Sex Pheromone of a Protected Species, the Spanish Moon Moth Graellsia isabellae

Sex attractant pheromones are highly sensitive and selective tools for detecting and monitoring populations of insects, yet there has been only one reported case of pheromones being used to monitor protected species. Here, we report the identification and synthesis of the sex pheromone of a protected European moth species, Graellsia isabellae (Lepidoptera: Saturniidae), as the single component, (4E,6E,11Z)-hexadecatrienal. In preliminary field trials, lures loaded with this compound attracted male moths from populations of this species at a number of widely separated field sites in France, Switzerland, and Spain, clearly demonstrating the utility of pheromones in sampling potentially endangered insect species