Hough Transform Sensitivity Factor Calculation Model Applied to the Analysis of Acne Vulgaris Skin Lesions

[EN] The number of infectious spots or pathological structures recorded on dermatological images is a tool to aid in the diagnosis and monitoring of disease progression. Dermatological images for the detection and monitoring of the evolution of acne infections are evaluated globally, comparing whether the increase or decrease in infectious lesions appearing on an image is significant. This evaluation method is only indicative since its accuracy is low. The accuracy problem could be improved by an exact count of the number of structures and spots appearing on the image. The mathematical function circular Hough transform (CHT) function implemented in MATLAB is here applied to develop a procedure for counting these structures. CHT has been used in the recognition of benign and distorted red blood cells, in the detection of pellet sizes in industrial processes and in the automated detection and morphological characterization of breast tumor masses from infrared images, as well as for the detection of brain aneurysms and use in magnetic resonance imaging. The sensitivity factor is one of the many parameters required to feed the CHT algorithm. Its choice is unclear as there is no proper methodology to select an optimum value suitable for each image. In this work, a procedure for determining the optimal value of the sensitivity factor is proposed The approach is validated by comparison with the results of the manual counting of the points (ground truth).This work was supported for publication by the Conselleria de Innovación, Universidades, Ciencia y Sociedad Digital of the Generalitat Valenciana. All this work has been done in the CITG (Research Centre in Graphic Technologies) at the Universitat Politècnica de València.Moncho-Santonja, M.; Micó-Vicent, B.; Defez Garcia, B.; Jordán-Núñez, J.; Peris Fajarnes, G. (2022). Hough Transform Sensitivity Factor Calculation Model Applied to the Analysis of Acne Vulgaris Skin Lesions. Applied Sciences. 12(3):1-12. https://doi.org/10.3390/app12031691S11212

Ostreopsis cf. ovata y Ostreopsis lenticularis (Dinophyceae: Gonyaulacales) en la Reserva Marina de Galápagos

The genus of benthic dinoflagellates Ostreopsis is of particular interest because some species negatively impact human health and coastal marine ecosystems. Ostreopsis populations from a remote area, such as the Galapagos Marine Reserve with its unique biodiversity, can provide significant data. Samples of epibionthic dinoflagellates were collected from two islands (Santa Cruz and Santa Fé) in 2017. Species of the genera Gambierdiscus, Amphidinium, Coolia and Ostreopsis were found. Ostreopsis strains were isolated to characterize their morphology, molecular biology and toxicity. Three dif­ferent morphotypes of Ostreopsis based on dorsoventral and width diameters (n=369) were distinguished. The small cell morphotype was dominant in ten samples, with abundances of up to 33405 cells g-1 fresh weight of macroalgae. A total of 16 strains were isolated from field samples with subsequent polymerase chain reaction amplifications of rDNA, 5.8S rDNA and internal transcribed space regions; 13 strains (small cell morphotype) clustered in the O. cf. ovata Atlantic/Indian/Pacific clade; and 3 strains (large cell morphotype) clustered in the Ostreopsis lenticularis genotype from the type locality. The strains proved to be non-toxic. The presence of these genera/species represents a potential threat to marine ecosystems, and it is thus important to consider benthic species in the surveillance of harmful algae blooms in the reserve.El género de los dinoflagelados bentónicos Ostreopsis es de particular interés, porque algunas especies afectan negativamente a la salud humana y a los ecosistemas marinos costeros. Las poblaciones de Ostreopsis en áreas remotas, como la Reserva Marina de Galápagos con su biodiversidad única, pueden proporcionar datos significativos a su estudio. Se recolectaron muestras de dinoflagelados epibentónicos de dos islas (Santa Cruz y Santa Fé) en 2017. Se encontraron espe­cies de los géneros Gambierdiscus, Amphidinium, Coolia y Ostreopsis. Las cepas de Ostreopsis se aislaron para caracterizar su morfología, biología molecular y toxicidad. Se distinguieron tres morfotipos diferentes de Ostreopsis basados en tamaño (n=369). El morfotipo de células pequeñas fue dominante en diez muestras, con abundancias de hasta 33405 células g–1 de peso fresco de macroalgas. Se aisló un total de 16 cepas y se secuenciaron las regiones de rDNA, 5.8S y ITS para el estudio filogenético. Trece cepas pertenecieron al morfotipo de células pequeñas agrupadas en el clado O. cf. ovata Atlántico/Índio/Pacífico y tres cepas al morfotipo de células grandes agrupadas en el clado Ostreopsis lenticularis. Ninguna de las cepas aisladas resultó ser tóxica. La presencia de estos géneros/especies representa una amenaza potencial para los ecosistemas marinos, por lo que es importante tener en cuenta las especies bentónicas en la vigilancia de la proliferación de algas nocivas en la reserva

Ostreopsis cf. ovata and Ostreopsis lenticularis (Dinophyceae: Gonyaulacales) in the Galapagos Marine Reserve

The genus of benthic dinoflagellates Ostreopsis is of particular interest because some species negatively impact human health and coastal marine ecosystems. Ostreopsis populations from a remote area, such as the Galapagos Marine Reserve with its unique biodiversity, can provide significant data. Samples of epibionthic dinoflagellates were collected from two islands (Santa Cruz and Santa Fé) in 2017. Species of the genera Gambierdiscus, Amphidinium, Coolia and Ostreopsis were found. Ostreopsis strains were isolated to characterize their morphology, molecular biology and toxicity. Three dif­ferent morphotypes of Ostreopsis based on dorsoventral and width diameters (n=369) were distinguished. The small cell morphotype was dominant in ten samples, with abundances of up to 33405 cells g-1 fresh weight of macroalgae. A total of 16 strains were isolated from field samples with subsequent polymerase chain reaction amplifications of rDNA, 5.8S rDNA and internal transcribed space regions; 13 strains (small cell morphotype) clustered in the O. cf. ovata Atlantic/Indian/Pacific clade; and 3 strains (large cell morphotype) clustered in the Ostreopsis lenticularis genotype from the type locality. The strains proved to be non-toxic. The presence of these genera/species represents a potential threat to marine ecosystems, and it is thus important to consider benthic species in the surveillance of harmful algae blooms in the reserve.El género de los dinoflagelados bentónicos Ostreopsis es de particular interés, porque algunas especies afectan negativamente a la salud humana y a los ecosistemas marinos costeros. Las poblaciones de Ostreopsis en áreas remotas, como la Reserva Marina de Galápagos con su biodiversidad única, pueden proporcionar datos significativos a su estudio. Se recolectaron muestras de dinoflagelados epibentónicos de dos islas (Santa Cruz y Santa Fé) en 2017. Se encontraron especies de los géneros Gambierdiscus, Amphidinium, Coolia y Ostreopsis. Las cepas de Ostreopsis se aislaron para caracterizar su morfología, biología molecular y toxicidad. Se distinguieron tres morfotipos diferentes de Ostreopsis basados en tamaño (n=369). El morfotipo de células pequeñas fue dominante en diez muestras, con abundancias de hasta 33405 células g–1 de peso fresco de macroalgas. Se aisló un total de 16 cepas y se secuenciaron las regiones de rDNA, 5.8S y ITS para el estudio filogenético. Trece cepas pertenecieron al morfotipo de células pequeñas agrupadas en el clado O. cf. ovata Atlántico/Índio/Pacífico y tres cepas al morfotipo de células grandes agrupadas en el clado Ostreopsis lenticularis. Ninguna de las cepas aisladas resultó ser tóxica. La presencia de estos géneros/especies representa una amenaza potencial para los ecosistemas marinos, por lo que es importante tener en cuenta las especies bentónicas en la vigilancia de la proliferación de algas nocivas en la reserva.info:eu-repo/semantics/publishedVersio

Retinal nerve fiber layer atrophy is associated with physical and cognitive disability in multiple sclerosis

Studying axonal loss in the retina is a promising biomarker for multiple sclerosis (MS). Our aim was to compare optical coherence tomography (OCT) and Heidelberg retinal tomography (HRT) techniques to measure the thickness of the retinal nerve fiber layer (RNFL) in patients with MS, and to explore the relationship between changes in the RNFL thickness with physical and cognitive disability. We studied 52 patients with MS and 18 proportionally matched controls by performing neurological examination, neuropsychological evaluation using the Brief Repetitive Battery-Neuropsychology and RNFL thickness measurement using OCT and HRT. RESULTS: We found that both OCT and HRT could define a reduction in the thickness of the RNFL in patients with MS compared with controls, although both measurements were weakly correlated, suggesting that they might measure different aspects of the tissue changes in MS. The degree of RNFL atrophy was correlated with cognitive disability, mainly with the symbol digit modality test (r=0.754, P<0.001). Moreover, temporal quadrant RNFL atrophy measured with OCT was associated with physical disability. CONCLUSION: In summary, both OCT and HRT are able to detect thinning of the RNFL, but OCT seems to be the most sensitive technique to identify changes associated with MS evolution

Host-Guest and Guest-Guest Interactions of P- and N-Containing Structure Directing Agents Entrapped inside MFI-Type Zeolite by Multinuclear NMR Spectroscopy

"This document is the Accepted Manuscript version of a Published Work that appeared in final form in The Journal of Physical Chemistry C, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://pubs.acs.org/doi/10.1021/acs.jpcc.9b05689".[EN] Highly crystalline pure silica MFI zeolites have been synthesized using tetraethylammonium (TEA), tetraethylphosphonium (TEP), or a mixture of both cations in different proportions as organic structure directing agents (OSDAs). The zeolites have been deeply characterized in order to get insight about the guest guest interactions involving the OSDAs and the guest host interactions involving the OSDAs and the inorganic framework, as well as the main features of the resulting materials. The results show that the average size of the MFI crystals decreases when TEP is present within the zeolite and that this cation is homogeneously distributed throughout the crystallites. The multinuclear NMR investigation (H-1, C-13, N-14, F-19, Si-29, P-31) indicates that TEP interacts with the zeolite host creating higher heterogeneity of the SiO4 crystallographic sites and a diminution on the mobility of fluorine atoms incorporated into the zeolite. Moreover, the presence of TEP influences the dynamics of the nitrogen atoms of the TEA molecules, and 2D heteronuclear correlation experiments give evidence on the spatial proximity of the TEA and TEP molecules in the MFI zeolites. Then, it is concluded that TEA and TEP are intimately mixed within the zeolite voids of the pure silica MFI samples synthesized by the dual template route.Financial support by the MINECO of Spain through the Severo Ochoa (SEV-2016-0683) and RTI2018-101784-B-I00 projects is gratefully acknowledged. The authors also thank the Microscopy Service of the Universitat Politecnica de Valencia for its assistance in microscopy characterization (FESEM equipment preparation). J.M.-O. (SEV-2012-0267-02) is grateful to the Severo Ochoa Program for a predoctoral fellowship.Martinez-Ortigosa, J.; Simancas-Coloma, J.; Vidal Moya, JA.; Gaveau, P.; Rey Garcia, F.; Alonso, B.; Blasco Lanzuela, T. (2019). Host-Guest and Guest-Guest Interactions of P- and N-Containing Structure Directing Agents Entrapped inside MFI-Type Zeolite by Multinuclear NMR Spectroscopy. The Journal of Physical Chemistry C. 123(36):22324-22334. https://doi.org/10.1021/acs.jpcc.9b05689S223242233412336Davis, M. E., & Lobo, R. F. (1992). Zeolite and molecular sieve synthesis. Chemistry of Materials, 4(4), 756-768. doi:10.1021/cm00022a005Cundy, C. S., & Cox, P. A. (2003). The Hydrothermal Synthesis of Zeolites:  History and Development from the Earliest Days to the Present Time. Chemical Reviews, 103(3), 663-702. doi:10.1021/cr020060iWilson, S. T., Lok, B. M., Messina, C. A., Cannan, T. R., & Flanigen, E. M. (1982). Aluminophosphate molecular sieves: a new class of microporous crystalline inorganic solids. Journal of the American Chemical Society, 104(4), 1146-1147. doi:10.1021/ja00368a062Liu, X., Yan, N., Wang, L., Ma, C., Guo, P., Tian, P., … Liu, Z. (2019). Landscape of AlPO-based structures and compositions in the database of zeolite structures. Microporous and Mesoporous Materials, 280, 105-115. doi:10.1016/j.micromeso.2019.01.047McCusker, L. B., Liebau, F., & Engelhardt, G. (2003). Nomenclature of structural and compositional characteristics of ordered microporous and mesoporous materials with inorganic hosts. Microporous and Mesoporous Materials, 58(1), 3-13. doi:10.1016/s1387-1811(02)00545-0Davis, M. E. (2013). Zeolites from a Materials Chemistry Perspective. Chemistry of Materials, 26(1), 239-245. doi:10.1021/cm401914uCorma, A., & Martinez, A. (1995). Zeolites and Zeotypes as catalysts. Advanced Materials, 7(2), 137-144. doi:10.1002/adma.19950070206Corma, A. (1997). From Microporous to Mesoporous Molecular Sieve Materials and Their Use in Catalysis. Chemical Reviews, 97(6), 2373-2420. doi:10.1021/cr960406nBurton, A. W., & Zones, S. I. (2007). Organic Molecules in Zeolite Synthesis: Their Preparation and Structure-Directing Effects. Introduction to Zeolite Science and Practice, 137-179. doi:10.1016/s0167-2991(07)80793-2Moliner, M., Rey, F., & Corma, A. (2013). Towards the Rational Design of Efficient Organic Structure-Directing Agents for Zeolite Synthesis. Angewandte Chemie International Edition, 52(52), 13880-13889. doi:10.1002/anie.201304713Martínez, C., & Corma, A. (2011). Inorganic molecular sieves: Preparation, modification and industrial application in catalytic processes. Coordination Chemistry Reviews, 255(13-14), 1558-1580. doi:10.1016/j.ccr.2011.03.014Sastre, G., Vidal-Moya, J. A., Blasco, T., Rius, J., Jordá, J. L., Navarro, M. T., … Corma, A. (2002). Preferential Location of Ge Atoms in Polymorph C of Beta Zeolite (ITQ-17) and Their Structure-Directing Effect: A Computational, XRD, and NMR Spectroscopic Study. Angewandte Chemie International Edition, 41(24), 4722-4726. doi:10.1002/anie.200290028Chauhan, N. L., Das, J., Jasra, R. V., Parikh, P. A., & Murthy, Z. V. P. (2012). Synthesis of small-sized ZSM-5 zeolites employing mixed structure directing agents. Materials Letters, 74, 115-117. doi:10.1016/j.matlet.2012.01.094Mitani, E., Yamasaki, Y., Tsunoji, N., Sadakane, M., & Sano, T. (2018). Synthesis of phosphorus-modified AFX zeolite using a dual-template method with tetraethylphosphonium hydroxide as phosphorus modification agent. Microporous and Mesoporous Materials, 267, 192-197. doi:10.1016/j.micromeso.2018.03.033Blasco, T., Corma, A., Díaz-Cabañas, M. J., Rey, F., Vidal-Moya, J. A., & Zicovich-Wilson, C. M. (2002). Preferential Location of Ge in the Double Four-Membered Ring Units of ITQ-7 Zeolite. The Journal of Physical Chemistry B, 106(10), 2634-2642. doi:10.1021/jp013302bCamblor, M. A., Villaescusa, L. A., & Díaz‐Cabañas, M. J. (1999). Topics in Catalysis, 9(1/2), 59-76. doi:10.1023/a:1019154304344Koller, H., Wölker, A., Villaescusa, L. A., Díaz-Cabañas, M. J., Valencia, S., & Camblor, M. A. (1999). Five-Coordinate Silicon in High-Silica Zeolites. Journal of the American Chemical Society, 121(14), 3368-3376. doi:10.1021/ja9840549Koller, H., Wölker, A., Eckert, H., Panz, C., & Behrens, P. (1997). Five-Coordinate Silicon in Zeolites: Probing SiO4/2F− Sites in Nonasil and ZSM-5 with29Si Solid-State NMR Spectroscopy. Angewandte Chemie International Edition in English, 36(24), 2823-2825. doi:10.1002/anie.199728231Dědeček, J., Tabor, E., & Sklenak, S. (2018). Tuning the Aluminum Distribution in Zeolites to Increase their Performance in Acid-Catalyzed Reactions. ChemSusChem, 12(3), 556-576. doi:10.1002/cssc.201801959Li, C., Vidal-Moya, A., Miguel, P. J., Dedecek, J., Boronat, M., & Corma, A. (2018). Selective Introduction of Acid Sites in Different Confined Positions in ZSM-5 and Its Catalytic Implications. ACS Catalysis, 8(8), 7688-7697. doi:10.1021/acscatal.8b02112Gallego, E. M., Portilla, M. T., Paris, C., León-Escamilla, A., Boronat, M., Moliner, M., & Corma, A. (2017). «Ab initio» synthesis of zeolites for preestablished catalytic reactions. Science, 355(6329), 1051-1054. doi:10.1126/science.aal0121Simancas, J., Simancas, R., Bereciartua, P. J., Jorda, J. L., Rey, F., Corma, A., … Mugnaioli, E. (2016). Ultrafast Electron Diffraction Tomography for Structure Determination of the New Zeolite ITQ-58. Journal of the American Chemical Society, 138(32), 10116-10119. doi:10.1021/jacs.6b06394Yun, Y., Hernández, M., Wan, W., Zou, X., Jordá, J. L., Cantín, A., … Corma, A. (2015). The first zeolite with a tri-directional extra-large 14-ring pore system derived using a phosphonium-based organic molecule. Chemical Communications, 51(36), 7602-7605. doi:10.1039/c4cc10317cSonoda, T., Maruo, T., Yamasaki, Y., Tsunoji, N., Takamitsu, Y., Sadakane, M., & Sano, T. (2015). Synthesis of high-silica AEI zeolites with enhanced thermal stability by hydrothermal conversion of FAU zeolites, and their activity in the selective catalytic reduction of NOx with NH3. Journal of Materials Chemistry A, 3(2), 857-865. doi:10.1039/c4ta05621cKakiuchi, Y., Tanigawa, T., Tsunoji, N., Takamitsu, Y., Sadakane, M., & Sano, T. (2019). Phosphorus modified small-pore zeolites and their catalytic performances in ethanol conversion and NH3-SCR reactions. Applied Catalysis A: General, 575, 204-213. doi:10.1016/j.apcata.2019.02.026Van der Bij, H. E., & Weckhuysen, B. M. (2015). Phosphorus promotion and poisoning in zeolite-based materials: synthesis, characterisation and catalysis. Chemical Society Reviews, 44(20), 7406-7428. doi:10.1039/c5cs00109aBLASCO, T., CORMA, A., & MARTINEZTRIGUERO, J. (2006). Hydrothermal stabilization of ZSM-5 catalytic-cracking additives by phosphorus addition. Journal of Catalysis, 237(2), 267-277. doi:10.1016/j.jcat.2005.11.011Liu, X., & Luo, Q. (2017). Solid State NMR Spectroscopy Studies of the Nature of Structure Direction of OSDAs in Pure-Silica Zeolites ZSM-5 and Beta. The Journal of Physical Chemistry C, 121(24), 13211-13217. doi:10.1021/acs.jpcc.7b03350Fyfe, C. A., & Brouwer, D. H. (2006). Optimization, Standardization, and Testing of a New NMR Method for the Determination of Zeolite Host−Organic Guest Crystal Structures. Journal of the American Chemical Society, 128(36), 11860-11871. doi:10.1021/ja060744yDib, E., Gimenez, A., Mineva, T., & Alonso, B. (2015). Preferential orientations of structure directing agents in zeolites. Dalton Transactions, 44(38), 16680-16683. doi:10.1039/c5dt02558cDib, E., Mineva, T., Gaveau, P., & Alonso, B. (2013). 14N solid-state NMR: a sensitive probe of the local order in zeolites. Physical Chemistry Chemical Physics, 15(42), 18349. doi:10.1039/c3cp51845kDib, E., Mineva, T., Gaveau, P., Véron, E., Sarou-Kanian, V., Fayon, F., & Alonso, B. (2017). Probing Disorder in Al-ZSM-5 Zeolites by 14N NMR Spectroscopy. The Journal of Physical Chemistry C, 121(29), 15831-15841. doi:10.1021/acs.jpcc.7b04861Tuel, A., Ben Taǎrit, Y., & Naccache, C. (1993). Characterization of TS-1 synthesized using mixtures of tetrabutyl and tetraethyl ammonium hydroxides. Zeolites, 13(6), 454-461. doi:10.1016/0144-2449(93)90120-rDing, J., Xue, T., Wu, H., & He, M. (2017). One-step post-synthesis treatment for preparing hydrothermally stable hierarchically porous ZSM-5. Chinese Journal of Catalysis, 38(1), 48-57. doi:10.1016/s1872-2067(16)62549-4Schmidt-Rohr, K., Clauss, J., & Spiess, H. W. (1992). Correlation of structure, mobility, and morphological information in heterogeneous polymer materials by two-dimensional wideline-separation NMR spectroscopy. Macromolecules, 25(12), 3273-3277. doi:10.1021/ma00038a037Massiot, D., Fayon, F., Capron, M., King, I., Le Calvé, S., Alonso, B., … Hoatson, G. (2001). Modelling one- and two-dimensional solid-state NMR spectra. Magnetic Resonance in Chemistry, 40(1), 70-76. doi:10.1002/mrc.984Chen, X., Yan, W., Cao, X., Yu, J., & Xu, R. (2009). Fabrication of silicalite-1 crystals with tunable aspect ratios by microwave-assisted solvothermal synthesis. Microporous and Mesoporous Materials, 119(1-3), 217-222. doi:10.1016/j.micromeso.2008.10.015Schmidt, J. E., Fu, D., Deem, M. W., & Weckhuysen, B. M. (2016). Template–Framework Interactions in Tetraethylammonium‐Directed Zeolite Synthesis. Angewandte Chemie International Edition, 55(52), 16044-16048. doi:10.1002/anie.201609053Baerlocher, Ch.; McCusker, L. B. Database of Zeolite Structures. http://www.iza-structure.org/databases/.Fyfe, C. A., Brouwer, D. H., Lewis, A. R., Villaescusa, L. A., & Morris, R. E. (2002). Combined Solid State NMR and X-ray Diffraction Investigation of the Local Structure of the Five-Coordinate Silicon in Fluoride-Containing As-Synthesized STF Zeolite. Journal of the American Chemical Society, 124(26), 7770-7778. doi:10.1021/ja012558sFyfe, C. A., Brouwer, D. H., Lewis, A. R., & Chézeau, J.-M. (2001). Location of the Fluoride Ion in Tetrapropylammonium Fluoride Silicalite-1 Determined by 1H/19F/29Si Triple Resonance CP, REDOR, and TEDOR NMR Experiments. Journal of the American Chemical Society, 123(28), 6882-6891. doi:10.1021/ja010532vBrunklaus, G., Koller, H., & Zones, S. I. (2016). Defect Models of As-Made High-Silica Zeolites: Clusters of Hydrogen-Bonds and Their Interaction with the Organic Structure-Directing Agents Determined from1H Double and Triple Quantum NMR Spectroscopy. Angewandte Chemie International Edition, 55(46), 14459-14463. doi:10.1002/anie.201607428Koller, H., Lobo, R. F., Burkett, S. L., & Davis, M. E. (1995). SiO-.cntdot. .cntdot. .cntdot.HOSi Hydrogen Bonds in As-Synthesized High-Silica Zeolites. The Journal of Physical Chemistry, 99(33), 12588-12596. doi:10.1021/j100033a036Dib, E., Grand, J., Mintova, S., & Fernandez, C. (2015). Structure-Directing Agent Governs the Location of Silanol Defects in Zeolites. Chemistry of Materials, 27(22), 7577-7579. doi:10.1021/acs.chemmater.5b03668Losch, P., Pinar, A. B., Willinger, M. G., Soukup, K., Chavan, S., Vincent, B., … Louis, B. (2017). H-ZSM-5 zeolite model crystals: Structure-diffusion-activity relationship in methanol-to-olefins catalysis. Journal of Catalysis, 345, 11-23. doi:10.1016/j.jcat.2016.11.005Dib, E., Alonso, B., & Mineva, T. (2014). DFT-D Study of 14N Nuclear Quadrupolar Interactions in Tetra-n-alkyl Ammonium Halide Crystals. The Journal of Physical Chemistry A, 118(19), 3525-3533. doi:10.1021/jp502858nMineva, T., Gaveau, P., Galarneau, A., Massiot, D., & Alonso, B. (2011). 14N: A Sensitive NMR Probe for the Study of Surfactant–Oxide Interfaces. The Journal of Physical Chemistry C, 115(39), 19293-19302. doi:10.1021/jp206567

Oscillator Strengths and Damping Constants for Atomic Lines in the J and H Bands

We have built a line list in the near-infrared J and H bands (1.00-1.34, 1.49-1.80 um) by gathering a series of laboratory and computed line lists. Oscillator strengths and damping constants were computed or obtained by fitting the solar spectrum. The line list presented in this paper is, to our knowledge, the most complete one now available, and supersedes previous lists.Comment: Accepted, Astrophysical Journal Supplement, tentatively scheduled for the Sep. 1999 Vol. 124 #1 issue. Text and tables also available at http://www.iagusp.usp.br/~jorge

Stellar Population gradients in galaxy discs from the CALIFA survey

While studies of gas-phase metallicity gradients in disc galaxies are common, very little has been done in the acquisition of stellar abundance gradients in the same regions. We present here a comparative study of the stellar metallicity and age distributions in a sample of 62 nearly face-on, spiral galaxies with and without bars, using data from the CALIFA survey. We measure the slopes of the gradients and study their relation with other properties of the galaxies. We find that the mean stellar age and metallicity gradients in the disc are shallow and negative. Furthermore, when normalized to the effective radius of the disc, the slope of the stellar population gradients does not correlate with the mass or with the morphological type of the galaxies. Contrary to this, the values of both age and metallicity at $\sim$2.5 scale-lengths correlate with the central velocity dispersion in a similar manner to the central values of the bulges, although bulges show, on average, older ages and higher metallicities than the discs. One of the goals of the present paper is to test the theoretical prediction that non-linear coupling between the bar and the spiral arms is an efficient mechanism for producing radial migrations across significant distances within discs. The process of radial migration should flatten the stellar metallicity gradient with time and, therefore, we would expect flatter stellar metallicity gradients in barred galaxies. However, we do not find any difference in the metallicity or age gradients in galaxies with without bars. We discuss possible scenarios that can lead to this absence of difference.Comment: 24 pages, 17 figures, accepted for publication in A&