UV properties of early-type galaxies in the Virgo cluster

We study the UV properties of a volume limited sample of early-type galaxies in the Virgo cluster combining new GALEX far- (1530 A) and near-ultraviolet (2310 A) data with spectro-photometric data available at other wavelengths. The sample includes 264 ellipticals, lenticulars and dwarfs spanning a large range in luminosity (M(B)<-15). While the NUV to optical or near-IR color magnitude relations (CMR) are similar to those observed at optical wavelengths, with a monotonic reddening of the color index with increasing luminosity, the (FUV-V) and (FUV-H) CMRs show a discontinuity between massive and dwarf objects. An even more pronounced dichotomy is observed in the (FUV-NUV) CMR. For ellipticals the (FUV-NUV) color becomes bluer with increasing luminosity and with increasing reddening of the optical or near-IR color indices. For the dwarfs the opposite trend is observed. These observational evidences are consistent with the idea that the UV emission is dominated by hot, evolved stars in giant systems, while in dwarf ellipticals residual star formation activity is more common.Comment: 5 pages, 2 figures, 1 table. Accepted for publication in Astrophysical Journal Letter

In vitro effect photodynamic therapy with differents photosensitizers on cariogenic microorganisms

Background Antimicrobial photodynamic therapy has been proposed as an alternative to suppress subgingival species. This results from the balance among Streptococcus sanguis, Streptococcus mutans and Candida albicans in the dental biofilm. Not all the photosensitizers have the same photodynamic effect against the different microorganims. The objective of this study is to compare in vitro the photodynamic effect of methylene blue (MB), rose Bengal (RB) and curcumin (CUR) in combination with white light on the cariogenic microorganism S. mutans, S. sanguis and C. albicans. Go to: Results Photodynamic therapy with MB, RB and CUR inhibited 6 log 10 the growth of both bacteria but at different concentrations: 0.31–0.62 μg/ml and 0.62–1.25 μg/ml RB were needed to photoinactivate S. mutans and S. sanguis, respectively; 1.25–2.5 μg/ml MB for both species; whereas higher CUR concentrations (80–160 μg/ml and 160–320 μg/ml) were required to obtain the same reduction in S. mutans and S. sanguis viability respectively. The minimal fungicidal concentration of MB for 5 log10 CFU reduction (4.5 McFarland) was 80–160 μg/ml, whereas for RB it ranged between 320 and 640 μg/ml. For CUR, even the maximum studied concentration (1280 μg/ml) did not reach that inhibition. Incubation time had no effect in all experiments. Go to: Conclusions Photodynamic therapy with RB, MB and CUR and white light is effective in killing S. mutans and S. sanguis strains, although MB and RB are more efficient than CUR. C. albicans required higher concentrations of all photosensitizers to obtain a fungicidal effect, being MB the most efficient and CUR ineffective.España, Ministerio de Ciencia e Innovación CTQ2013-48767-C3-2-

Mesoscopic rings with Spin-Orbit interactions

A didactic description of charge and spin equilibrium currents on mesoscopic rings in the presence of Spin-Orbit interaction is presented. Emphasis is made on the non trivial construction of the correct Hamiltonian in polar coordinates, the calculation of eigenvalues and eigenfunctions and the symmetries of the ground state properties. Spin currents are derived following an intuitive definition and then a more thorough derivation is built upon the canonical Lagrangian formulation that emphasizes the SU(2) gauge structure of the transport problem of spin 1/2 fermions in spin-orbit active media. The quantization conditions that follow from the constraint of single-valued Pauli spinors are also discussed. The targeted students are those of a graduate Condensed Matter Physics course

Qubit Decoherence and Non-Markovian Dynamics at Low Temperatures via an Effective Spin-Boson Model

Quantum Brownian oscillator model (QBM), in the Fock-space representation, can be viewed as a multi-level spin-boson model. At sufficiently low temperature, the oscillator degrees of freedom are dynamically reduced to the lowest two levels and the system behaves effectively as a two-level (E2L) spin-boson model (SBM) in this limit. We discuss the physical mechanism of level reduction and analyze the behavior of E2L-SBM from the QBM solutions. The availability of close solutions for the QBM enables us to study the non-Markovian features of decoherence and leakage in a SBM in the non-perturbative regime (e.g. without invoking the Born approximation) in better details than before. Our result captures very well the characteristic non-Markovian short time low temperature behavior common in many models.Comment: 19 pages, 8 figure

A contribution to the selection of emission-line galaxies using narrow-band filters in the optical airglow windows

Emission line galaxies are an invaluable tool for our understanding of the evolution of galaxies in the Universe. Imaging of deep fields with narrow-band filters allows not only the selection of these objects, but also to infer the line flux and the equivalent width of the emission line with some assumptions. The narrow-band filter technique provides homogeneous samples of galaxies in small comoving volumes in the sky. We present an analysis of the selection of emission-line galaxies using narrow-band filters. Different methods of observation are considered: broad-band -- narrow-band filters and two broad-band and one narrow-band filters. We study also the effect of several lines entering simultaneously inside the filters (this is the case of Halpha). In each case the equations to obtain the equivalent width and line flux from the photometry are obtained. Candidates to emission-line objects are selected by their color excess in a magnitude-color diagram. For different narrow-band filters, we compute the mean colors of stars and galaxies, showing that, apart from galaxies, some types of stars could be selected with certain filter sets. We show how to compute the standard deviation of the colors of the objects even in the usual case when there are not enough objects to determine the standard deviation from the data. We present also helpful equations to compute the narrow-band and the broad-band exposure times in order to obtain minimum dispersion in the ratio of fluxes of both bands with minimum total exposure time.Comment: Accepted for publication in PASP 48 pages, 10 figures Corrected typos, fixed references. Updated reference to T

Fast determination of thiacloprid by photoinduced chemiluminescence

This paper was published in Applied Spectroscopy and is made available as an electronic reprint with the permission of OSA. The paper can be found at the following URL on the OSA website: http://www.opticsinfobase.org/as/abstract.cfm?URI=as-68-6-642. Systematic or multiple reproduction or distribution to multiple locations via electronic or other means is prohibited and is subject to penalties under law.A new and sensitive application of the chemiluminescence detection has been developed for the determination of the pesticide thiacloprid in water. It was based on the on-line photoreaction of thiacloprid in basic medium, with quinine acting as sensitizer of the chemiluminescent response; Cerium (IV) in sulfuric acid medium was used as oxidant. A high automation and reproducibility was provided by a flow injection analysis (FIA) manifold. The validation of the method was performed in terms of selectivity, linearity, LOD, precision and accuracy. Liquid chromatography with UV detection was used as reference for mineral, tap, ground and spring water samples. The proposed method is fast (throughput of 130 h-1), sensitive (LOD of 0.8 ng mL-1 without preconcentration steps and 0.08 ng mL-1 with solid phase extraction (SPE)), low-cost and possible to couple with separative methods for the simultaneous determination of other pesticides. The enhanced chemiluminescence intensity was linear with thiacloprid concentration over the (2-80) and (80-800) ng mL-1 ranges. A possible reaction mechanism is also discussed.The authors thank the Ministerio de Educacion y Ciencia of Spain and the Fondo Europeo de Desarrollo Regional for financial support, Project CTM2006-11991.Catalá Icardo, M.; López Paz, JL.; Pérez Plancha, LM. (2014). Fast determination of thiacloprid by photoinduced chemiluminescence. Applied Spectroscopy. 68(6):642-648. https://doi.org/10.1366/13-07330S642648686Tomizawa, M., & Casida, J. E. (2005). NEONICOTINOID INSECTICIDE TOXICOLOGY: Mechanisms of Selective Action. Annual Review of Pharmacology and Toxicology, 45(1), 247-268. doi:10.1146/annurev.pharmtox.45.120403.095930Tapparo, A., Giorio, C., Soldà, L., Bogialli, S., Marton, D., Marzaro, M., & Girolami, V. (2012). UHPLC-DAD method for the determination of neonicotinoid insecticides in single bees and its relevance in honeybee colony loss investigations. Analytical and Bioanalytical Chemistry, 405(2-3), 1007-1014. doi:10.1007/s00216-012-6338-3Tennekes, H. A., & Sánchez-Bayo, F. (2013). The molecular basis of simple relationships between exposure concentration and toxic effects with time. Toxicology, 309, 39-51. doi:10.1016/j.tox.2013.04.007Peña, A., Rodríguez-Liébana, J. A., & Mingorance, M. D. (2011). Persistence of two neonicotinoid insecticides in wastewater, and in aqueous solutions of surfactants and dissolved organic matter. Chemosphere, 84(4), 464-470. doi:10.1016/j.chemosphere.2011.03.039Di Muccio, A., Fidente, P., Barbini, D. A., Dommarco, R., Seccia, S., & Morrica, P. (2006). Application of solid-phase extraction and liquid chromatography–mass spectrometry to the determination of neonicotinoid pesticide residues in fruit and vegetables. Journal of Chromatography A, 1108(1), 1-6. doi:10.1016/j.chroma.2005.12.111Fidente, P., Seccia, S., Vanni, F., & Morrica, P. (2005). Analysis of nicotinoid insecticides residues in honey by solid matrix partition clean-up and liquid chromatography–electrospray mass spectrometry. Journal of Chromatography A, 1094(1-2), 175-178. doi:10.1016/j.chroma.2005.09.012Seccia, S., Fidente, P., Barbini, D. A., & Morrica, P. (2005). Multiresidue determination of nicotinoid insecticide residues in drinking water by liquid chromatography with electrospray ionization mass spectrometry. Analytica Chimica Acta, 553(1-2), 21-26. doi:10.1016/j.aca.2005.08.006Pareja, L., Martínez-Bueno, M. J., Cesio, V., Heinzen, H., & Fernández-Alba, A. R. (2011). Trace analysis of pesticides in paddy field water by direct injection using liquid chromatography–quadrupole-linear ion trap-mass spectrometry. Journal of Chromatography A, 1218(30), 4790-4798. doi:10.1016/j.chroma.2011.02.044Seccia, S., Fidente, P., Montesano, D., & Morrica, P. (2008). Determination of neonicotinoid insecticides residues in bovine milk samples by solid-phase extraction clean-up and liquid chromatography with diode-array detection. Journal of Chromatography A, 1214(1-2), 115-120. doi:10.1016/j.chroma.2008.10.088Wang, W., Li, Y., Wu, Q., Wang, C., Zang, X., & Wang, Z. (2012). Extraction of neonicotinoid insecticides from environmental water samples with magnetic graphene nanoparticles as adsorbent followed by determination with HPLC. Analytical Methods, 4(3), 766. doi:10.1039/c2ay05734dBi, X., & Yang, K.-L. (2009). On-Line Monitoring Imidacloprid and Thiacloprid in Celery Juice Using Quartz Crystal Microbalance. Analytical Chemistry, 81(2), 527-532. doi:10.1021/ac801786aGámiz-Gracia, L., Garcı́a-Campaña, A. M., Soto-Chinchilla, J. J., Huertas-Pérez, J. F., & González-Casado, A. (2005). Analysis of pesticides by chemiluminescence detection in the liquid phase. TrAC Trends in Analytical Chemistry, 24(11), 927-942. doi:10.1016/j.trac.2005.05.009Roda, A., & Guardigli, M. (2011). Analytical chemiluminescence and bioluminescence: latest achievements and new horizons. Analytical and Bioanalytical Chemistry, 402(1), 69-76. doi:10.1007/s00216-011-5455-8Du, J., & Li, H. (2010). Sensitive Chemiluminescence Determination of Thirteen Cephalosporin Antibiotics with Luminol—Copper(II) Reaction. Applied Spectroscopy, 64(10), 1154-1159. doi:10.1366/000370210792973613Li, Y., Li, Y., & Yang, Y. (2011). Flow-Injection Chemiluminescence Determination of Lisinopril Using Luminol–KMnO4 Reaction Catalyzed by Silver Nanoparticles. Applied Spectroscopy, 65(4), 376-381. doi:10.1366/10-06115Catalá-Icardo, M., López-Paz, J. L., Choves-Barón, C., & Peña-Bádena, A. (2012). Native vs photoinduced chemiluminescence in dimethoate determination. Analytica Chimica Acta, 710, 81-87. doi:10.1016/j.aca.2011.10.043Mestre, Y. F., Zamora, L. L., & Calatayud, J. M. (2001). Flow-chemiluminescence: a growing modality of pharmaceutical analysis. Luminescence, 16(3), 213-235. doi:10.1002/bio.608Lara, F. J., García-Campaña, A. M., & Aaron, J.-J. (2010). Analytical applications of photoinduced chemiluminescence in flow systems—A review. Analytica Chimica Acta, 679(1-2), 17-30. doi:10.1016/j.aca.2010.09.001Icardo, M. C., & Calatayud, J. M. (2008). Photo-Induced Luminescence. Critical Reviews in Analytical Chemistry, 38(2), 118-130. doi:10.1080/10408340802039609RICART, I., ANTONFOS, G., DUART, M., MATEO, J., ZAMORA, L., & CALATAYUD, J. (2007). Theoretical prediction of the photoinduced chemiluminescence of pesticides. Talanta, 72(2), 378-386. doi:10.1016/j.talanta.2006.10.048Abramović, B. F., Banić, N. D., & Šojić, D. V. (2010). Degradation of thiacloprid in aqueous solution by UV and UV/H2O2 treatments. Chemosphere, 81(1), 114-119. doi:10.1016/j.chemosphere.2010.07.016Icardo, M. (2003). FI-on line photochemical reaction for direct chemiluminescence determination of photodegradated chloramphenicol. Talanta, 60(2-3), 405-414. doi:10.1016/s0039-9140(03)00074-2Zhao, Y., Baeyens, W. R. G., Zhang, X., Calokerinos, A. C., Nakashima, K., & Der Weken, G. V. (1997). Chemiluminescence Determination of Tiopronin by Flow Injection Analysis Based on Cerium(IV) Oxidation Sensitized by Quinine. The Analyst, 122(2), 103-106. doi:10.1039/a605703iZhang, Z., Baeyens, W. R. G., Zhang, X., Zhao, Y., & Van Der Weken, G. (1997). Chemiluminescence detection coupled to liquid chromatography for the determination of penicillamine in human urine. Analytica Chimica Acta, 347(3), 325-332. doi:10.1016/s0003-2670(97)00171-2Capitán-Vallvey, L. (2000). Chemiluminescence determination of sodium 2-mercaptoethane sulfonate by flow injection analysis using cerium(IV) sensitized by quinine. Talanta, 51(6), 1155-1161. doi:10.1016/s0039-9140(00)00291-5NIE, L., MA, H., SUN, M., LI, X., SU, M., & LIANG, S. (2003). Direct chemiluminescence determination of cysteine in human serum using quinine–Ce(IV) system. Talanta, 59(5), 959-964. doi:10.1016/s0039-9140(02)00649-5Lakowicz, J. R. (Ed.). (2006). Principles of Fluorescence Spectroscopy. doi:10.1007/978-0-387-46312-4Lookabaugh, M., & Krull, I. S. (1988). Determination of nitrite and nitrate by reversed-phase high-performance liquid chromatography using on-line post-column photolysis with ultraviolet absorbance and electrochemical detection. Journal of Chromatography A, 452, 295-308. doi:10.1016/s0021-9673(01)81454-0Gómez-Benito, C., Meseguer-Lloret, S., & Torres-Cartas, S. (2013). Sensitive determination of Fenamiphos in water samples by flow injection photoinduced chemiluminescence. International Journal of Environmental Analytical Chemistry, 93(2), 152-165. doi:10.1080/03067319.2012.663755CATALÁ-ICARDO, M., LÓPEZ-PAZ, J. L., & PEÑA-BÁDENA, A. (2011). FI-photoinduced Chemiluminescence Method for Diuron Determination in Water Samples. Analytical Sciences, 27(3), 291. doi:10.2116/analsci.27.291Hamilton, D. J., Ambrus, Á., Dieterle, R. M., Felsot, A. S., Harris, C. A., Holland, P. T., … Wong, S.-S. (2003). Regulatory limits for pesticide residues in water (IUPAC Technical Report). Pure and Applied Chemistry, 75(8), 1123-1155. doi:10.1351/pac20037508112

Las “moscas de las flores” (Diptera: Syrphidae) en Lules, Tucumán

La familia Syrphidae es un grupo de insectos que se caracteriza por ser moscas grandes y vistosas capaces de adoptar la apariencia de abejas o avispas para defenderse de los depredadores. Los adultos generalmente se encuentran sobre las flores o en vuelo suspendido en lugares soleados, de ahí que sean llamados comúnmente “moscas de las flores” o “flower flies”. Su tamaño fluctúa de 4 a 25 mm, el cuerpo puede ser delgado o robusto y presentar coloración metálica u opaca. El abdomen es variable en forma, de ancho a muy delgado (Sarmiento Cordero et al., 2010).Fil: Maza, Noelia. Universidad Nacional de Tucumán. Facultad de Agronomía y Zootecnia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Sopena, Y. N.. Universidad Nacional de Tucumán. Facultad de Agronomía y Zootecnia; ArgentinaFil: Assaf, M. J. T.. Universidad Nacional de Tucumán. Facultad de Agronomía y Zootecnia; ArgentinaFil: Paz, Miriam Rosana. Universidad Nacional de Tucumán. Facultad de Agronomía y Zootecnia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Jaime, Adriana Patricia. Universidad Nacional de Tucumán. Facultad de Agronomía y Zootecnia; Argentin

HESS-II reconstruction strategy and performance in the low-energy (20-150 GeV) domain

International audienceIn mid-2009 a notable upgrade of the H.E.S.S. telescope system will take place: a new telescope with a 600 m2 mirror area and very-high-resolution camera (0.07°) will be positioned at the centre of the present configuration, with the aim of lowering the threshold and enhance its sensitivity in the 100 GeV to several TeV energy range. HESS-II will permit the investigation of the lower energy gamma-ray spectra in various cosmic accelerators, giving information on the origin of the gamma-rays observed, and will detect AGNs with a redshift greater than 0.2 (being less affected by absorption by Extragalactic Background Light-EBL-in this energy range) and will search for new classes of very high energy gamma-ray emitters (pulsars, microquasars, GRB, and dark matter candidates)

Non-Equilibrium Quantum Fields in the Large N Expansion

An effective action technique for the time evolution of a closed system consisting of one or more mean fields interacting with their quantum fluctuations is presented. By marrying large $N$ expansion methods to the Schwinger-Keldysh closed time path (CTP) formulation of the quantum effective action, causality of the resulting equations of motion is ensured and a systematic, energy conserving and gauge invariant expansion about the quasi-classical mean field(s) in powers of $1/N$ developed. The general method is exposed in two specific examples, $O(N)$ symmetric scalar \l\F^4 theory and Quantum Electrodynamics (QED) with $N$ fermion fields. The \l\F^4 case is well suited to the numerical study of the real time dynamics of phase transitions characterized by a scalar order parameter. In QED the technique may be used to study the quantum non-equilibrium effects of pair creation in strong electric fields and the scattering and transport processes in a relativistic $e^+e^-$ plasma. A simple renormalization scheme that makes practical the numerical solution of the equations of motion of these and other field theories is described.Comment: 43 pages, LA-UR-94-783 (PRD, in press), uuencoded PostScrip