156 research outputs found

    Multicolonization of human nasopharynx due to Neisseria spp.

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    The colonization due to Neisseria spp. in the nasopharynx of forty healthy adults was studied by using a selective medium that allows the differentiation of Neisseria species and inhibits the rest of pharyngeal microbiota. The medium detected a variety of colonial morphology types and some metabolic characteristics of the isolates. We demonstrated the multicolonization by several Neisseria spp. in the same individual, and we isolated several strains of the same species, after analysis by pulsed-field gel electrophoresis (PFGE) patterns obtained from the different colonial types previously identified as the same species. The forty adults studied were colonized by 112 forms of Neisseria spp., and twelve colonization patterns were obtained: one species (45%), two (45%), three (7.5%) and four (2.5%). N. perflava-N. sicca, either alone or in combination with other species was the most frequent isolate (92.5%). The analysis of PFGE patterns obtained from different colonial types revealed the multicolonization by several strains of the same species in some individuals. This fact was found in N. perflava-N. sicca (50%) and N. mucosa (2.5%)

    Morphometric characteristics and internal structures of intertidal bars on the northwest Cadiz littoral (southwestern Iberian Peninsula)

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    The present paper deals with morphometric bar characteristics, to discriminate between bars that are associated with dissipative beaches and reflective ones. We shall focus on the former: their internal structures and migration rate. The beaches studied are located between the cities of Chipiona and Rota (southwest Iberian Peninsula). Dissipative beaches have a gentle slope (2 %) and are 120 m wide; moderately reflective beaches have a 5 % slope and are 90 m wide. We found that bars associated with reflective beaches are larger than those associated with dissipative beaches. On the reflective beaches, bars are convex upwards, with a seaward slope of 9° and a landward slope of 5°. On the dissipative beaches, bars have a wide, smooth crest, a seaward slope of 2°-3°, and a landward slope of 1°-2°. They are generally composed of thin sets of plane bedding laminae, parallel to the beach surface.Este trabajo pretende una descripción morfométrica de las barras intermareales para distinguir entre las asociadas a perfiles disipativos y las asociadas a perfiles reflectivos, profundizando más en las primeras en cuanto a estructuras internas y migración. El litoral estudiado se sitúa entre las ciudades de Chipiona y Rota (suroeste de la península Ibérica). Las playas disipativas presentan pendiente muy suave (2 %) y anchura de aproximadamente 120 m; las reflectivas tienen pendiente media del 5 % y anchura en torno a 90 m. Se ha encontrado que las barras asociadas a perfiles reflectivos son de mayores dimensiones que las asociadas a perfiles disipativos. Aquéllas son convexas y tienen una elevada pendiente en su lado hacia el mar (9°) y una pendiente menor en el lado hacia tierra. Las últimas presentan una amplia y aplanada cresta, el lado hacia el mar tiene una pendiente de 2°-3° y el lado hacia tierra de 1°-2°. Sus estructuras internas están constituidas por láminas paralelas a la superficie.Instituto Español de Oceanografí

    Transmission of Streptococcus pyogenes causing successive infections in a family

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    The objective of this study was to determine the characteristics of Streptococcus pyogenes isolated during a 10-month period from members of a family with infections and asymptomatic carriage. T-serotyping and pulsed-field gel electrophoresis confirmed that distinct GAS clones were introduced into the family over a short period of time

    Study of the dynamics of third-order iterative methods on quadratic polynomials

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    In this paper, we analyse the dynamical behaviour of the operators associated with multi-point interpolation iterative methods and frozen derivative methods, for solving nonlinear equations, applied on second-degree complex polynomials. We obtain that, in both cases, the Julia set is connected and separates the basins of attraction of the roots of the polynomial. Moreover, the Julia set of the operator associated with multi-point interpolation methods is the same as the Newton operator, although it is more complicated for the frozen derivative operator. We explain these differences by obtaining the conjugacy function of each method and by showing that the operators associated with Newton's method and multi-point interpolation methods are both conjugate to powers of z.The authors thank Professors X. Jarque and A. Garijo for their help. The authors also thank the referees for their valuable comments and suggestions that have improved the content of this paper. This research was supported by Ministerio de Ciencia y Tecnologia MTM2011-28636-C02-02 and by Vicerrectorado de Invetigacion, Universitat Politecnica de Valencia, PAID-06-2010-2285Cordero Barbero, A.; Torregrosa Sánchez, JR.; Vindel Cañas, P. (2012). Study of the dynamics of third-order iterative methods on quadratic polynomials. International Journal of Computer Mathematics. 89(13):1826-1836. https://doi.org/10.1080/00207160.2012.687446S182618368913Amat, S., Busquier, S., & Plaza, S. (2006). A construction of attracting periodic orbits for some classical third-order iterative methods. Journal of Computational and Applied Mathematics, 189(1-2), 22-33. doi:10.1016/j.cam.2005.03.049Amat, S., Bermúdez, C., Busquier, S., & Plaza, S. (2008). On the dynamics of the Euler iterative function. Applied Mathematics and Computation, 197(2), 725-732. doi:10.1016/j.amc.2007.08.086Amat, S., Busquier, S., & Plaza, S. (2010). Chaotic dynamics of a third-order Newton-type method. Journal of Mathematical Analysis and Applications, 366(1), 24-32. doi:10.1016/j.jmaa.2010.01.047Blanchard, P. (1995). The dynamics of Newton’s method. Proceedings of Symposia in Applied Mathematics, 139-154. doi:10.1090/psapm/049/1315536Cordero, A., & Torregrosa, J. R. (2010). On interpolation variants of Newton’s method for functions of several variables. Journal of Computational and Applied Mathematics, 234(1), 34-43. doi:10.1016/j.cam.2009.12.002Cordero, A., Hueso, J. L., Martínez, E., & Torregrosa, J. R. (2009). Multi-Point Iterative Methods for Systems of Nonlinear Equations. Lecture Notes in Control and Information Sciences, 259-267. doi:10.1007/978-3-642-02894-6_25Cordero, A., Hueso, J. L., Martínez, E., & Torregrosa, J. R. (2010). Iterative methods for use with nonlinear discrete algebraic models. Mathematical and Computer Modelling, 52(7-8), 1251-1257. doi:10.1016/j.mcm.2010.02.028Curry, J. H., Garnett, L., & Sullivan, D. (1983). On the iteration of a rational function: Computer experiments with Newton’s method. Communications in Mathematical Physics, 91(2), 267-277. doi:10.1007/bf01211162Douady, A., & Hubbard, J. H. (1985). On the dynamics of polynomial-like mappings. Annales scientifiques de l’École normale supérieure, 18(2), 287-343. doi:10.24033/asens.1491Frontini, M., & Sormani, E. (2003). Some variant of Newton’s method with third-order convergence. Applied Mathematics and Computation, 140(2-3), 419-426. doi:10.1016/s0096-3003(02)00238-2Gutiérrez, J. M., Hernández, M. A., & Romero, N. (2010). Dynamics of a new family of iterative processes for quadratic polynomials. Journal of Computational and Applied Mathematics, 233(10), 2688-2695. doi:10.1016/j.cam.2009.11.017Özban, A. . (2004). Some new variants of Newton’s method. Applied Mathematics Letters, 17(6), 677-682. doi:10.1016/s0893-9659(04)90104-8PLAZA, S. (2001). CONJUGACIES CLASSES OF SOME NUMERICAL METHODS. Proyecciones (Antofagasta), 20(1). doi:10.4067/s0716-09172001000100001Plaza, S., & Romero, N. (2011). Attracting cycles for the relaxed Newton’s method. Journal of Computational and Applied Mathematics, 235(10), 3238-3244. doi:10.1016/j.cam.2011.01.010F.A. Potra and V. Pták,Nondiscrete Introduction and Iterative Processes, Research Notes in Mathematics Vol. 103, Pitman, Boston, MA, 1984

    Sulfur and lead isotope systematics: Implications for the genesis of the Riópar Zn-(Fe-Pb) carbonate-hosted deposit (Prebetic Zone, SE Spain)

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    The Zn-(Fe-Pb) deposits of the Riópar area (Prebetic Zone, SE Spain) are hosted by dolostones that replace Berriasian to Valanginian (Upper Jurassic-Lower Cretaceous) limestones. Mineralization consists of hypogene sphalerite, marcasite and galena, and supergene calamine zones. The hypogene ores are associated with a saddle dolomite gangue. The ore bodies occur as discordant and stratiform lenses, ore-cemented breccias, cm- to mm-wide veins and veinlets, disseminations and stylolite porosity filling within the host dolomites. The main ore controls include stratigraphy and/or lithology, tectonics (faults, fractures and breccias) and availability of metals and sulfur. The morphologies and epigenetic character of the hypogene ore bodies are consistent with the classification of this mineralization as a Mississippi Valley-type (MVT) deposit. The Ga/Ge geothermometer in sphalerite yielded a temperature range of 194-252ºC, which represents the temperature of the source region of the ore solution. This value is comparable to the temperature obtained in the ore deposition site, 159±15ºC from the Δ34S geothermometer in sphalerite galena pairs. This similitude points to a hydrothermal fluid that did not cool down significantly during flow from the fluid reservoir area to the precipitation site. δ34S values of base-metal sulfides (-7.5 to +3.5 ¿) are consistent with thermochemical reduction of Triassic sulfate (seawater and/or derived from dissolution of evaporites) by interaction with organic compounds (e.g., hydrocarbons, methane), which reduced sulfate to sulfide in the deposition site. The lead isotope ratios (206Pb/204Pb = 18.736-18.762; 207Pb/204Pb = 15.629-15.660; 208Pb/204Pb = 38.496-38.595) of galena suggest that Pb, and probably other metals as Zn, is derived from continental crustal rocks. On the other hand, these relations points to an unique metal source probably derived from the Paleozoic basement rocks. The relationship between bedding-parallel stylolites, dolomitization, sulfide precipitation and Alpine tectonic affecting the MVT ore, suggests a relative timing range for the mineralization in the Riópar area of 95 to 20 Ma (Upper Cretaceous-Tertiary). The sulfide mineralization and the associated dolomitization are thus explained by the contribution of two fluids that mixed in different proportions during dolomitization and mineralization: i) a fluid probably derived from Cretaceous seawater saturating Mesozoic sediments (Fluid A), characterized by being dilute and initially low temperature, which should have contained organic rich compounds in the ore deposition site (e.g., hydrocarbons and CH4 dissolved gas); and ii) a high salinity hydrothermal brine (Fluid B) rich in both metals and sulfate, circulated through the Paleozoic basement. During the pre-ore dolomitizing stage the fluid phase was dominated by the diluted fluid (Fluid A > Fluid B), whereas in a later fluid pulse, the proportion of the high salinity fluid increased (Fluid A < Fluid B) which allowed sulfide precipitation. MVT exploration in the Prebetic Zone should focus towards the SW of the Riópar mines, in the vicinity of the Alto Guadalquivir-San Jorge fault

    Petrography and geochemistry of fault-controlled hydrothermal dolomites in the Riópar area (Prebetic Zone, SE Spain)

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    The present paper reports the first detailed petrographical and geochemical studies of hydrothermal dolomites related to MVT Zn-(Fe-Pb) deposits in the Riópar area (Mesozoic Prebetic Basin, SE Spain), constraining the nature, origin and evolution of dolomitizing and ore-forming fluids. Mapping and stratigraphic studies revealed two stratabound dolostone geobodies connected by other patchy bodies, which replace carbonate units of Upper Jurassic to Lower Cretaceous ages. These dolostones are associated to the W-E trending San Jorge fault, indicating a main tectonic control for fluid flow. Seven different dolomite types were identified: i) matrix-replacive planar-s (ReD-I); ii) matrix-replacive planar-e (ReD-II); iii) planar-e sucrosic cement (SuD); iv) non-planar grey saddle dolomite cement (SaD-I) pre-dating Zn-(Fe-Pb) sulfides; v) non-planar milky to pinkish saddle dolomite cement (SaD-II) post-dating Zn-(Fe-Pb) ores; vi) ore-replacive planar-e porphyrotopic (PoD); and vii) planar-s cloudy cement (CeD). Meteoric calcite types were also recognized. The different dolomite types are isotopically characterized by: i) depleted δ18O (from +25.1 to +27.6¿ V-SMOW) and δ13C (from -2.3 to +0.9¿ V-PDB) values compared to Upper Jurassic to Lower Cretaceous limestone signature (δ18O: +27.6 to +30.9¿ V-SMOW; δ13C: +0.5 to +3.2¿ V-PDB); and ii) 87Sr/86Sr ratios for the main dolomitization phases (ReD and SuD: 0.70736-0.70773) close to the Jurassic and Cretaceous carbonate values (0.70723-0.70731) whereas more radiogenic values (0.70741-0.70830) for saddle dolomites (SaD) related to the Zn-(Fe-Pb) sulfide mineralization prevailed after fluid interaction with Rb-bearing minerals. Microthermometrical studies on two-phase liquid and vapor fluid inclusion populations in planar and non-planar dolomites and sphalerite show homogenization temperatures between 150 and 250ºC. These data indicate that both planar and non-planar dolomite textures formed at high-temperatures under hydrothermal conditions in deep-burial diagenetic environments. The main dolomitizing phase (ReD-I/ReD-II and SaD-I) shows low to moderate fluid inclusions salinity (5 to 14 wt.% eq. NaCl), whereas the dolomitization related to ore precipitation (sphalerite and SaD-II) spreads to higher salinity values (5 to 25 wt.% eq. NaCl). These data may respond to a mixing between a low salinity fluid (fluid A, less than 5 wt.% eq. NaCl) and a more saline brine (fluid B, more than 25 wt.% eq. NaCl) at different fluid proportions

    Dynamics of the family of c-iterative methods

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    In this paper, the dynamics of the family of c-iterative methods for solving nonlinear equations are studied on quadratic polynomials. A singular parameter space is presented to show the complexity of the family. The analysis of the parameter space allows us to find elements of the family that have bad convergence properties and also other ones with very stable behaviour. These schemes correspond to values of c in different small regions of the parameter space.Supported by Ministerio de Ciencia y Tecnologia MTM2011-28636-C02-02. The first and fourth authors were also partially supported by P11B2011-30 (Universitat Jaume I), the second and third authors were also partially supported by Vicerrectorado de Investigacion, Universitat Politecnica de Valencia PAID-06-2010-2285.Campos, B.; Cordero Barbero, A.; Torregrosa Sánchez, JR.; Vindel, P. (2015). Dynamics of the family of c-iterative methods. International Journal of Computer Mathematics. 92(9):1815-1825. https://doi.org/10.1080/00207160.2014.893608S1815182592

    An additional set of phages to characterize epidemic methicillin-resistant Staphylococcus aureus strains from Spain (1989-92).

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    In recent years, methicillin-resistant Staphylococcus aureus (MRSA) isolates in Spain have increased dramatically; in 1986 there were only 1.2% MRSA amongst all nosocomial Staphylococcus aureus (SA) isolates, by 1989 this percentage had risen to 44% in some hospital causing a very serious epidemic situation in the country. We have characterized these isolates by direct, reverse and Fisk phage typing and we have also looked for an additional local set of phages to help us to differentiate these strains. We have been able to differentiate an epidemic strain from other MRSA strains which cause sporadic hospital outbreaks, and we have also distinguished between some variants of the epidemic strain.This research has been supported by a grant from the Fondo de Investigaciones Sanitarias de la Seguridad Social (FISS), Ministerio de Sanidad y Consumo, Spain; No. 93/0144.S

    Mineralogical and geochemical characterization of the Riópar non-sulfide Zn-(Fe-Pb) deposits (Prebetic Zone, SE Spain)

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    The present paper reports the first detailed petrological and geochemical study of non-sulfide Zn-(Fe-Pb) deposits in the Riópar area (Prebetic Zone of the Mesozoic Betic Basin, SE Spain), constraining the origin and evolution of ore-forming fluids. In Riópar both sulfide and non-sulfide Zn-(Fe-Pb) ('calamine') ores are hosted in hydrothermally dolomitized Lower Cretaceous limestones. The hypogene sulfides comprise sphalerite, marcasite and minor galena. Calamine ores consist of Zn-carbonates (smithsonite and scarce hydrozincite), associated with abundant Fe-(hydr)oxides (goethite and hematite) and minor Pb-carbonates (cerussite). Three smithsonite types have been recognized: i) Sm-I consists of brown anhedral microcrystalline aggregates as encrustations replacing sphalerite; ii) Sm-II refers to brownish subhedral aggregates of rugged appearance related with Fe oxi-hydroxides in the surface crystals, which replace extensively sphalerite; and iii) Sm-III smithsonite appears as coarse grayish botryoidal aggregates in microkarstic cavities and porosity. Hydrozincite is scarce and appears as milky white botryoidal encrustations in cavities replacing smithsonite. Also, two types of cerussite have been identified: i) Cer-I cerussite consists of fine crystals replacing galena along cleavage planes and crystal surfaces; and ii) Cer-II conforms fine botryoidal crystals found infill porosity. Calcite and thin gypsum encrustations were also recognized. The field and petrographic observations of the Riópar non-sulfide Zn-(Fe-Pb) revealed two successive stages of supergene ore formation under meteoric fluid processes: i) 'gossan' and 'red calamine' formation in the uppermost parts of the ore with deposition of Fe-(hydr)oxides and Zn- and Pb-carbonates (Sm-I, Sm-II and Cer-I), occurring as direct replacements of Zn-Pb sulfides; and ii) 'gray calamine' ore formation with deposition of Sm-III, Cer-II and hydrozincite infilling microkarst cavities and porosity. The stable isotope variation of Riópar smithsonite is very similar to those obtained in other calamine-ore deposits around the world. Their C-O isotope data (δ18O: +27.8 to +29.6¿ V-SMOW; δ13C: -6.3 to +0.4¿ V-PDB), puts constrains on: i) the oxidizing fluid type, which was of meteoric origin with temperatures of 12 to 19ºC, suggesting a supergene weathering process for the calamine-ore formation under a temperate climate; and ii) the carbon source, that resulted from mixing between two CO2 components derived from: the dissolution of host-dolomite (13C-enriched source) and vegetation decomposition (13C-depleted component)

    The association between different domains of quality of life and symptoms in primary care patients with emotional disorders

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    Despite the importance of quality of life (QoL) in primary care patients with emotional disorders, the specific influence of the symptoms of these disorders and the sociodemographic characteristics of patients on the various QoL domains has received scant attention. The aim of the present study of primary care patients with emotional disorders was to analyse the associations between four different QoL domains and the most prevalent clinical symptoms (i.e., depression, anxiety and somatization), while controlling for sociodemographic variables. A total of 1241 participants from 28 primary care centres in Spain were assessed with the following instruments: the Patient Health Questionnaire (PHQ)-9 to evaluate depression; the Generalized Anxiety Disorder Scale (GAD)-7 for anxiety; PHQ-15 for somatization; and the World Health Organization Quality of Life Instrument-Short Form (WHOQOL- Bref) to assess four broad QoL domains: physical health, psychological health, social relationships, and environment. The associations between the symptoms and QoL domains were examined using hierarchical regression analyses. Adjusted QoL mean values as a function of the number of overlapping diagnoses were calculated. The contribution of sociodemographic variables to most QoL domains was modest, explaining anywhere from 2% to 11% of the variance. However, adding the clinical variables increased the variance explained by 12% to 40% depending on the specific QoL domain. Depression was the strongest predictor for all domains. The number of overlapping diagnoses adversely affected all QoL domains, with each additional diagnosis reducing the main QoL subscales by 5 to 10 points. In primary care patients with a diagnostic impression of an emotional disorders as identified by their treating GP, clinical symptoms explained more of the variance in QoL than sociodemographic factors such as age, sex, level of education, marital status, work status, and income. Given the strong relationship between depressive symptoms and QoL, treatment of depression may constitute a key therapeutic target to improve QoL in people with emotional disorders in primary care
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