234 research outputs found

    Morphological variation of the labellum of Vanilla planifolia Andrews (Orchidaceae) in Oaxaca, Mexico

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    Infraspecific variation has transcendental ecological consequences for species adaptation to new niches. Estimating levels of variation is key for understanding the life history of a species, as well as for designing strategies for use and conservation. For this reason, the objective of this study was to characterize infra-specific morphological variation of the labellum of V. planifolia, of 122 flowers from 28 specimens from the state of Oaxaca and two specimens from Veracruz, Mexico. The labellum of each flower was dissected and analyzed by morphometry. Sixty variables were obtained and grouped into basal, middle and apical regions. An analysis of variance was performed considering the collections and the origin of each individual as sources of variation. Principal components and cluster analyses were also conducted. Differences in the 60 variables analyzed were highly significant among the collections. Among environments, 18 variables showed significant differences, which were situated in the lateral and middle lobes of the labellum. Thus, these structures were considered susceptible to environmental changes. The remaining 42 variables situated in the basal and middle regions of the labellum, which were fused to the edges of the floral column were not significantly different among environments. With the first three principal components, the model explained 73% of the total variation studied. Morphological variation of the flower labellum was represented by four morphotypes distributed in three environments. Highlights The evaluation of vanilla flowers wild does not allow to have the same number of treatments or repetitions, for the inaccessibility of the species. Morphometric analysis of the labellum revealed infra-specific variation in the germplasm of Vanilla planifolia. The features of the basal and middle regions of the labellum are the most informative in distinguishing the variation between vanilla specimens.Infraspecific variation has transcendental ecological consequences for species adaptation to new niches. Estimating levels of variation is key for understanding the life history of a species, as well as for designing strategies for use and conservation. For this reason, the objective of this study was to characterize infra-specific morphological variation of the labellum of V. planifolia, of 122 flowers from 28 specimens from the state of Oaxaca and two specimens from Veracruz, Mexico. The labellum of each flower was dissected and analyzed by morphometry. Sixty variables were obtained and grouped into basal, middle and apical regions. An analysis of variance was performed considering the collections and the origin of each individual as sources of variation. Principal components and cluster analyses were also conducted. Differences in the 60 variables analyzed were highly significant among the collections. Among environments, 18 variables showed significant differences, which were situated in the lateral and middle lobes of the labellum. Thus, these structures were considered susceptible to environmental changes. The remaining 42 variables situated in the basal and middle regions of the labellum, which were fused to the edges of the floral column were not significantly different among environments. With the first three principal components, the model explained 73% of the total variation studied. Morphological variation of the flower labellum was represented by four morphotypes distributed in three environments. Highlights The evaluation of vanilla flowers wild does not allow to have the same number of treatments or repetitions, for the inaccessibility of the species. Morphometric analysis of the labellum revealed infra-specific variation in the germplasm of Vanilla planifolia. The features of the basal and middle regions of the labellum are the most informative in distinguishing the variation between vanilla specimens

    Ubicación de la secuencia repetitiva PFCOL692 en fragmentos genómicos de Plasmodíum falciparum

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    In this paper we established the subtelomeric localization of the repetitive sequence PFCOL692 of Plasmodium falciparum by the characterization of four clones from a hEMBL41 PFCOL692 genomic library, which contains 15-23Kbp long inserts of parasite genomic DNA. Characterization was made by restriction analysis and the PFCOL692 localization in the genome was explored using specific probes for telomeric (pTB4.1) and subtelomeric regions (pRep20) of P falciparum chromosomes. We proposed a possible organization for the parasite chromosomes ends, where the copies of PFCOL692 are clusters in the subtelomeric region and their localization is conserved with respect to the pRep20 sequence. In addition, we established that PFCOL692 is not located next to the telomere.Las secuencias repetitivas son componentes estructurales de los genomas eucariotes. Se desconoce la función de la mayoría de ellas, pero, al parecer, no son simplemente ADN egoísta sino que intervienen en procesos de recombinación y regulación génica. En este estudio se estableció la localización subtelomérica dela secuencia repetitiva PFCOL692 en los cromosomas de Plasmodium falciparum, a través de la caracterización de cuatro clones de la genoteca ?EMBL4/PFCOL692, que contenían insertos entre 15 y 23Kb de ADN genómico del parásito; esta caracterización se hizo mediante análisis de restricción y la posible ubicación de PFCOL692 en el genoma se exploró utilizando sondas específicas para las regiones telomérica (pTB4.1) y subtelomérica (pRep20) de los cromosomas de P. falciparum. El análisis de los mapas de restricción obtenidos permitió plantear una posible ubicación de PFCOL692 en el extremo de los cromosomas del parásito, donde las copias de esta secuencia se encuentran agrupadas en un segmento del subtelómero y con una posición conservada con respecto a la secuencia pRep20 Se sugiere, además, que PFCOL692 no se encuentra en el limite entre el subtelómero y el telómero

    Comparison Among Booth’s and Pekmestzi’s Algorithms for the Multiplication of Two Numbers

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    A comparison between two different methods of multiplication of two 8-bit numbers is presented. This methods are the Booth’s algorithm and the algorithm proposed by Kiamal Z. Pekmestzi [1]. The general objective is to show the benefits and the advantages obtained if it’s used one of this algorithms over the other. This multipliers have low circuit complexity permitting high-speed operations and the interconnections of the cells are regular. This is the reason why the results shown was obtained using VHDL realization on a FPGA XC4010XL by Xilinx.Consejo de Ciencia y Tecnología del Estado de GuanajuatoConsejo Nacional de Ciencia y TecnologíaUniversidad de GuanajuatoXili

    LIVER BIOCHEMISTRY PROFILE IN WHITE-TAILED DEER (ODOCOILEUS VIRGINIANUS) REARED IN CAPTIVITY

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    El presente estudio se llevó a cabo con 23 venados cola blanca (Odocoileus virginianus), de ambos sexos, y criados en cautiverio en la provincia de Lima, con el objetivo de determinar el perfil bioquímico sanguíneo hepático a través de los valores séricos de Bilirrubina Total y Directa, Proteínas Totales, Albúmina, Alanino Amino Transferasa (ALT), Aspartato Amino Transferasa (AST), Fosfatasa Alcalina (FA), y Gamma Glutamil Transferasa (GGT). Los animales (7 machos y 16 hembras), pertenecientes a tres zoológicos o zoocriaderos, fueron anestesiados con clorhidrato de ketamina o con la combinación de clorhidrato de ketamina y clorhidrato de xilacina. Se extrajo 7 ml de sangre por punción de la vena safena en tubos estériles sin anticoagulante, y los sueros fueron analizados con kits comerciales. Los valores encontrados (media ± DE) fueron para Bilirrubina Total: 0.6 ± 0.3 mg/dl; Bilirrubina Directa: 0.08 ± 0.06 mg/dl; Proteínas Totales: 6.6 ± 0.7 g/dl; Albúmina: 3.6 ± 0.5 g/dl; ALT: 26.0 ± 9.7 UI/l; AST: 87.6 ± 22.9 UI/l; FA: 73.9 ± 33.8 UI/l; y GGT: 42.5 ± 12.6 UI/l. No hubo diferencia estadística entre sexos con excepción de BT y albúmina (p<0.05).This study was carried out with 23 adult white-tailed deer (Odocoileus virginianus)of both sexes, kept in captivity in the province of Lima to establish reference liverbiochemistry profilevalues (Total and direct bilirubin, total protein, albumin, alanineamino transferase (ALT), aspartate amino transferase (AST), alkaline phosphatase (AF),and gamma glutamyl transferase (GGT). The animals (7 males and 16 females) were from three local zoos and were anesthesyzed with ketamine hydrochloride or with acombination of ketamine hydrochloride and xylazine hydrochloride. Blood samples (7ml) were collected from the saphenous vein in sterile tubes and serum was analyzedusing commercial kits. The values (mean ± SD) were Total Bilirubin: 0.6 ± 0.3 mg/dl;Direct Bilirubin: 0.08 ± 0.06 mg/dl; Total Protein: 6.6 ± 0.7 g/dl; Albumin: 3.6 ± 0.5 g/dl;ALT: 26.0 ± 9.7 UI/l; AST: 87.6 ± 22.9 UI/l; AF: 73.9 ± 33.8 UI/l, and GGT: 42.5 ± 12.6 UI/l.There were no statistical differences due to sex except for total bilirubin and albumin(p<0.05

    Ab-initio calculation of the electronic and optical excitations in polythiophene: effects of intra- and interchain screening

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    We present an calculation of the electronic and optical excitations of an isolated polythiophene chain as well as of bulk polythiophene. We use the GW approximation for the electronic self-energy and include excitonic effects by solving the electron-hole Bethe-Salpeter equation. The inclusion of interchain screening in the case of bulk polythiophene drastically reduces both the quasi-particle band gap and the exciton binding energies, but the optical gap is hardly affected. This finding is relevant for conjugated polymers in general.Comment: 4 pages, 1 figur

    Spectral characteristics of side face excited microstructured fibers for photonic integrated circuits formations

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    We propose a new method for mass production of the photonic crystal devices on the basis of widely-known and well-developed technology such as microstructured optical fibers. In this paper, we investigate the optical properties of side-excited microstructured optical fiber and discuss the conditions for utilization such a structure as a planar photonic crystal device, namely, the high-quality resonance filter.Comment: 7 pages, 7 figure

    Agglomerations and firm performance: who benefits and how much?

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    [EN] Agglomerations and firm performance: who benefits and how much? Regional Studies. Agglomeration can generate gains. If it does, how does it work and how are those gains distributed across agglomerated firms? The paper examines the effect of localization externalities on innovation. Localization externalities are measured as industry specialization or a firm s colocation in a relatively high own-industry employment region. By analyzing a large dataset of 6697 firms integrated with another regional agglomeration-related dataset, results show that (1) co-location in an agglomeration has a positive influence on a firm s innovative performance; and (2) firms benefit heterogeneously from agglomerations, with benefits being distributed asymmetrically. Agglomeration gains exist but not all firms benefit equally.Financial support was provided by the Spanish Ministry of Economics, Industry and Competitiveness [research grant ECO:2015-63645-R] (Mineco/Feder), Open Innovation in Clusters.Hervás Oliver, JL.; Sempere-Ripoll, F.; Rojas Alvarado, RJ.; Estelles Miguel, S. (2018). Agglomerations and firm performance: who benefits and how much?. Regional Studies. 52(3):338-349. https://doi.org/10.1080/00343404.2017.1297895S33834952

    Ab-initio prediction of the electronic and optical excitations in polythiophene: isolated chains versus bulk polymer

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    We calculate the electronic and optical excitations of polythiophene using the GW approximation for the electronic self-energy, and include excitonic effects by solving the electron-hole Bethe-Salpeter equation. Two different situations are studied: excitations on isolated chains and excitations on chains in crystalline polythiophene. The dielectric tensor for the crystalline situation is obtained by modeling the polymer chains as polarizable line objects, with a long-wavelength polarizability tensor obtained from the ab-initio polarizability function of the isolated chain. With this model dielectric tensor we construct a screened interaction for the crystalline case, including both intra- and interchain screening. In the crystalline situation both the quasi-particle band gap and the exciton binding energies are drastically reduced in comparison with the isolated chain. However, the optical gap is hardly affected. We expect this result to be relevant for conjugated polymers in general.Comment: 15 pages including 4 figures; to appear in Phys. Rev. B, 6/15/200

    Mendelian Randomization Analysis of the Relationship Between Native American Ancestry and Gallbladder Cancer Risk

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    Background A strong association between the proportion of Native American ancestry and the risk of gallbladder cancer (GBC) has been reported in observational studies. Chileans show the highest incidence of GBC worldwide, and the Mapuche are the largest Native American people in Chile. We set out to investigate the causal association between Native American Mapuche ancestry and GBC risk, and the possible mediating effects of gallstone disease and body mass index (BMI) on this association. Methods Markers of Mapuche ancestry were selected based on the informativeness for assignment measure and then used as instrumental variables in two-sample mendelian randomization (MR) analyses and complementary sensitivity analyses. Result We found evidence of a causal effect of Mapuche ancestry on GBC risk (inverse variance-weighted (IVW) risk increase of 0.8% for every 1% increase in Mapuche ancestry proportion, 95% CI 0.4% to 1.2%, p = 6.6×10-5). Mapuche ancestry was also causally linked to gallstone disease (IVW risk increase of 3.6% per 1% increase in Mapuche proportion, 95% CI 3.1% to 4.0%, p = 1.0×10-59), suggesting a mediating effect of gallstones in the relationship between Mapuche ancestry and GBC. In contrast, the proportion of Mapuche ancestry showed a negative causal effect on BMI (IVW estimate -0.006 kg/m2 per 1% increase in Mapuche proportion, 95% CI -0.009 to -0.003, p = 4.4×10-5). Conclusions The results presented here may have significant implications for GBC prevention and are important for future admixture mapping studies. Given that the association between Mapuche ancestry and GBC risk previously noted in observational studies appears to be causal, primary and secondary prevention strategies that take into account the individual proportion of Mapuche ancestry could be particularly efficient
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