2,141 research outputs found

    Growth response and heavy metals tolerance of Axonopus affinis, inoculated with plant growthpromoting rhizobacteria

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    Different microorganisms have been used for bioremediation based on their resistance and ability to sequester heavy metals. The use of plant growth-promoting rhizobacteria (PGPR) for bioremediation of these contaminants has been successful. A PGPR isolated from hydrocarbons-contaminated soil identified as Bacillus sp., by microbiological and molecular tools and characterized as heavy metal tolerant by minimal inhibitory concentration (MIC) assay was inoculated into Axonopus affinis plants. Both of them were exposed to cadmium, nickel, and zinc and the effect of their relationship was analyzed by multivariate analysis. The results did not show a significant growth promotion and development of this Poaceae with rhizobacteria alone, but the presence of heavy metals plus the PGPR assured the survival of plants. This suggests that the plant’s response is related with the metal concentration and the exposure time to the contaminants, as well as with its intrinsic tolerance. The Bacillus sp strain allowed the growth maintenance of A. affinis and enhanced its tolerance to the assayed heavy metals, suggesting a synergistic effect between this species and the rhizobacterium in response to contaminating agents.Keywords: Bioremediation, heavy metals, microorganisms, plant

    Repetitive DNA Restructuring Across Multiple Nicotiana Allopolyploidisation Events Shows a Lack of Strong Cytoplasmic Bias in Influencing Repeat Turnover.

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    Allopolyploidy is acknowledged as an important force in plant evolution. Frequent allopolyploidy in Nicotiana across different timescales permits the evaluation of genome restructuring and repeat dynamics through time. Here we use a clustering approach on high-throughput sequence reads to identify the main classes of repetitive elements following three allotetraploid events, and how these are inherited from the closest extant relatives of the maternal and paternal subgenome donors. In all three cases, there was a lack of clear maternal, cytoplasmic bias in repeat evolution, i.e., lack of a predicted bias towards maternal subgenome-derived repeats, with roughly equal contributions from both parental subgenomes. Different overall repeat dynamics were found across timescales of <0.5 (N. rustica L.), 4 (N. repanda Willd.) and 6 (N. benthamiana Domin) Ma, with nearly additive, genome upsizing, and genome downsizing, respectively. Lower copy repeats were inherited in similar abundance to the parental subgenomes, whereas higher copy repeats contributed the most to genome size change in N. repanda and N. benthamiana. Genome downsizing post-polyploidisation may be a general long-term trend across angiosperms, but at more recent timescales there is species-specific variance as found in Nicotiana

    Lepton Number Violation from Colored States at the LHC

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    The possibility to search for lepton number violating signals at the Large Hadron Collider (LHC) in the colored seesaw scenario is investigated. In this context the fields that generate neutrino masses at the one-loop level are scalar and Majorana fermionic color-octets of SU(3). Due to the QCD strong interaction these states may be produced at the LHC with a favorable rate. We study the production mechanisms and decays relevant to search for lepton number violation signals in the channels with same-sign dileptons. In the simplest case when the two fermionic color-octets are degenerate in mass, one could use their decays to distinguish between the neutrino spectra. We find that for fermionic octets with mass up to about 1 TeV the number of same-sign dilepton events is larger than the standard model background indicating a promising signal for new physics.Comment: minor corrections, added reference

    Maharam-type kernel representation for operators with a trigonometric domination

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    [EN] Consider a linear and continuous operator T between Banach function spaces. We prove that under certain requirements an integral inequality for T is equivalent to a factorization of T through a specific kernel operator: in other words, the operator T has what we call a Maharam-type kernel representation. In the case that the inequality provides a domination involving trigonometric functions, a special factorization through the Fourier operator is given. We apply this result to study the problem that motivates the paper: the approximation of functions in L2[0, 1] by means of trigonometric series whose Fourier coefficients are given by weighted trigonometric integrals.This research has been supported by MTM2016-77054-C2-1-P (Ministerio de Economia, Industria y Competitividad, Spain).Sánchez Pérez, EA. (2017). Maharam-type kernel representation for operators with a trigonometric domination. Aequationes Mathematicae. 91(6):1073-1091. https://doi.org/10.1007/s00010-017-0507-6S10731091916Calabuig, J.M., Delgado, O., Sánchez Pérez, E.A.: Generalized perfect spaces. Indag. Math. 19(3), 359–378 (2008)Calabuig, J.M., Delgado, O., Sánchez Pérez, E.A.: Factorizing operators on Banach function spaces through spaces of multiplication operators. J. Math. Anal. Appl. 364, 88–103 (2010)Delgado, O., Sánchez Pérez, E.A.: Strong factorizations between couples of operators on Banach function spaces. J. Convex Anal. 20(3), 599–616 (2013)Dodds, P.G., Huijsmans, C.B., de Pagter, B.: Characterizations of conditional expectation type operators. Pacific J. Math. 141(1), 55–77 (1990)Flores, J., Hernández, F.L., Tradacete, P.: Domination problems for strictly singular operators and other related classes. Positivity 15(4), 595–616 (2011). 2011Fremlin, D.H.: Tensor products of Banach lattices. Math. Ann. 211, 87–106 (1974)Hu, G.: Weighted norm inequalities for bilinear Fourier multiplier operators. Math. Ineq. Appl. 18(4), 1409–1425 (2015)Halmos, P., Sunder, V.: Bounded Integral Operators on L2 L^2 L 2 Spaces. Springer, Berlin (1978)Kantorovitch, L., Vulich, B.: Sur la représentation des opérations linéaires. Compositio Math. 5, 119–165 (1938)Kolwicz, P., Leśnik, K., Maligranda, L.: Pointwise multipliers of Calderón- Lozanovskii spaces. Math. Nachr. 286, 876–907 (2013)Kolwicz, P., Leśnik, K., Maligranda, L.: Pointwise products of some Banach function spaces and factorization. J. Funct. Anal. 266(2), 616–659 (2014)Kuo, W.-C., Labuschagne, C.C.A., Watson, B.A.: Conditional expectations on Riesz spaces. J. Math. Anal. Appl. 303, 509–521 (2005)Lindenstrauss, J., Tzafriri, L.: Classical Banach Spaces II. Springer, Berlin (1979)Maharam, D.: The representation of abstract integrals. Trans. Am. Math. Soc. 75, 154–184 (1953)Maharam, D.: On kernel representation of linear operators. Trans. Am. Math. Soc. 79, 229–255 (1955)Maligranda, L., Persson, L.E.: Generalized duality of some Banach function spaces. Indag. Math. 51, 323–338 (1989)Neugebauer, C.J.: Weighted norm inequalities for averaging operators of monotone functions. Publ. Mat. 35, 429–447 (1991)Okada, S., Ricker, W.J., Sánchez Pérez, E.A.: Optimal Domain and Integral Extension of Operators Acting in Function Spaces. Operator Theory: Adv. Appl., vol. 180. Birkhäuser, Basel (2008)Rota, G.C.: On the representation of averaging operators. Rend. Sem. Mat. Univ. Padova. 30, 52–64 (1960)Sánchez Pérez, E.A.: Factorization theorems for multiplication operators on Banach function spaces. Integr. Equ. Oper. Theory 80(1), 117–135 (2014)Schep, A.R.: Factorization of positive multilinear maps. Ill. J. Math. 28(4), 579–591 (1984)Schep, A.R.: Products and factors of Banach function spaces. Positivity 14(2), 301–319 (2010

    Predicting prostate cancer treatment choices: The role of numeracy, time discounting, and risk attitudes

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    Prostate cancer is the most common cancer among males in the United States and there is lack of consensus as to whether active surveillance (AS) or radical prostatectomy (RP) is the best course of treatment. In this study we examined the role of three overlooked determinants of decision making about prostate cancer treatment in a hypothetical experiment—numeracy, time discounting, and risk taking in 279 men over age 50 without a prior prostate cancer diagnosis. Results showed that AS was the most frequently chosen option. Furthermore, numeracy and time discounting significantly predicted participants’ preference for AS, whereas a propensity to take risks was associated with a preference for RP. Such insights into the factors that affects cancer treatment preferences may improve tailored decision aids and help physicians be better poised to engage in shared decision-making to improve both patient-reported and clinical outcomes

    The complete linkage disequilibrium test: a test that points to causative mutations underlying quantitative traits

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    <p>Abstract</p> <p>Background</p> <p>Genetically, SNP that are in complete linkage disequilibrium with the causative SNP cannot be distinguished from the causative SNP. The Complete Linkage Disequilibrium (CLD) test presented here tests whether a SNP is in complete LD with the causative mutation or not. The performance of the CLD test is evaluated in 1000 simulated datasets.</p> <p>Methods</p> <p>The CLD test consists of two steps i.e. analysis I and analysis II. Analysis I consists of an association analysis of the investigated region. The log-likelihood values from analysis I are next ranked in descending order and in analysis II the CLD test evaluates differences in log-likelihood ratios between the best and second best markers. Under the null-hypothesis distribution, the best SNP is in greater LD with the QTL than the second best, while under the alternative-CLD-hypothesis, the best SNP is alike-in-state with the QTL. To find a significance threshold, the test was also performed on data excluding the causative SNP. The 5<sup>th</sup>, 10<sup>th </sup>and 50<sup>th </sup>highest T<sub>CLD </sub>value from 1000 replicated analyses were used to control the type-I-error rate of the test at p = 0.005, p = 0.01 and p = 0.05, respectively.</p> <p>Results</p> <p>In a situation where the QTL explained 48% of the phenotypic variance analysis I detected a QTL in 994 replicates (p = 0.001), where 972 were positioned in the correct QTL position. When the causative SNP was excluded from the analysis, 714 replicates detected evidence of a QTL (p = 0.001). In analysis II, the CLD test confirmed 280 causative SNP from 1000 simulations (p = 0.05), i.e. power was 28%. When the effect of the QTL was reduced by doubling the error variance, the power of the test reduced relatively little to 23%. When sequence data were used, the power of the test reduced to 16%. All SNP that were confirmed by the CLD test were positioned in the correct QTL position.</p> <p>Conclusions</p> <p>The CLD test can provide evidence for a causative SNP, but its power may be low in situations with closely linked markers. In such situations, also functional evidence will be needed to definitely conclude whether the SNP is causative or not.</p

    RIESGO CARDIOVASCULAR DEL PERSONAL DE ENFERMERÍA EN EL ÁREA QUIRÚRGICA

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    The aim of the present investigation was to determine cardiovascular risk factors, through the Framingham model, in the Infirmary Personnel in the surgical area of the Instituto Autónomo Hospital Universitario de Los Andes Merida-Venezuela. A descriptive, field, and cross section study was made, with a population of 43 nurses. The analysis and interpretation of the results were made by descriptive statistics. Test results and the laboratory analysis proved that since age was a non modifiable factor, most of them were in the young adulthood and mature adulthood periods with low cardiovascular risk. As regards modifiable factors, it was determined that more than half had Total Cholesterol at normal levels. In relation to HDL Cholesterol, according to laboratory tests the results showed a high percentage of low values such as &lt;40 mg/dl, which translates as a possible increase of cardiovascular disease risk. As for smoking, more than half of the Infirmary Personnel declared not to have smoking habits. As for Arterial Pressure levels, it was determined that more than half of the professionals were within the normal parameters. When calculating the cardiovascular risk at 10 years, according to the Framingham Model, most of the nurses were located as “Very Low” and “Low” risk of suffering cardiovascular disease in 10 years. Nevertheless, 18.61% had a “Moderate” “High” and “Very High” risk of suffering cardiovascular diseases in the future, which requires proposing promotion and prevention activities aimed at improving the working and health conditions of the Infirmary Personnel and at diminishing cardiovascular risks that can affect their individual, family and community health.La presente investigación tuvo como objetivo determinar los factores de riesgo cardiovascular, a través del modelo de Framingham, en el Personal de Enfermería que labora en el área quirúrgica, Instituto Autónomo Hospital Universitario de Los Andes Mérida-Venezuela. Se realizó un estudio de tipo descriptivo, de campo y de corte transversal, con una población determinada por 43 enfermeras. El análisis e interpretación de los resultados se realizó con estadística descriptiva. Los resultados del test y los exámenes de laboratorio evidenciaron que siendo la edad un factor no modificable, la mayoría se encuentran en el periodo adultez joven y adultez madura con bajo riesgo cardiovascular. Con respecto a los factores modificables, se determinó que del Colesterol Total más de la mitad presentó niveles normales. En relación al Colesterol HDL, según los exámenes de laboratorio los resultados reflejaron: un alto porcentaje mostró cifras bajas, es decir &lt;40 mg/dl, lo cual se traduce en un posible aumento del riesgo a enfermedad cardiovascular. En cuanto al tabaquismo, más de la mitad del Personal de Enfermería manifestó no poseer hábitos tabáquicos. En lo referente a la medición de la Presión Arterial, se encontró que más de la mitad de los profesionales se encuentran en parámetros normales. Al calcular el riesgo cardiovascular a 10 años, según el Modelo de Framingham, la mayoría de las enfermeras, se ubicaron en “Muy Bajo” y “Bajo” riesgo de padecer enfermedad cardiovascular a 10 años. Sin embargo, el 18,61 % tienen un riesgo “Moderado”, “Alto” y “Muy Alto” de padecer en el futuro enfermedades cardiovasculares, lo que requiere de la propuesta de actividades de promoción y prevención, tendientes a mejorar las condiciones de trabajo y salud del Personal de Enfermería, orientadas a disminuir los riesgos cardiovasculares que puedan afectar su salud individual, familiar y en la comunidad

    Introducing a new breed of wine yeast: interspecific hybridisation between a commercial Saccharomyces cerevisiae wine yeast and Saccharomyces mikatae

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    Interspecific hybrids are commonplace in agriculture and horticulture; bread wheat and grapefruit are but two examples. The benefits derived from interspecific hybridisation include the potential of generating advantageous transgressive phenotypes. This paper describes the generation of a new breed of wine yeast by interspecific hybridisation between a commercial Saccharomyces cerevisiae wine yeast strain and Saccharomyces mikatae, a species hitherto not associated with industrial fermentation environs. While commercially available wine yeast strains provide consistent and reliable fermentations, wines produced using single inocula are thought to lack the sensory complexity and rounded palate structure obtained from spontaneous fermentations. In contrast, interspecific yeast hybrids have the potential to deliver increased complexity to wine sensory properties and alternative wine styles through the formation of novel, and wider ranging, yeast volatile fermentation metabolite profiles, whilst maintaining the robustness of the wine yeast parent. Screening of newly generated hybrids from a cross between a S. cerevisiae wine yeast and S. mikatae (closely-related but ecologically distant members of the Saccharomyces sensu stricto clade), has identified progeny with robust fermentation properties and winemaking potential. Chemical analysis showed that, relative to the S. cerevisiae wine yeast parent, hybrids produced wines with different concentrations of volatile metabolites that are known to contribute to wine flavour and aroma, including flavour compounds associated with non-Saccharomyces species. The new S. cerevisiae x S. mikatae hybrids have the potential to produce complex wines akin to products of spontaneous fermentation while giving winemakers the safeguard of an inoculated ferment.Jennifer R. Bellon, Frank Schmid, Dimitra L. Capone, Barbara L. Dunn, Paul J. Chamber

    Active wetting of epithelial tissues

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    Development, regeneration and cancer involve drastic transitions in tissue morphology. In analogy with the behavior of inert fluids, some of these transitions have been interpreted as wetting transitions. The validity and scope of this analogy are unclear, however, because the active cellular forces that drive tissue wetting have been neither measured nor theoretically accounted for. Here we show that the transition between 2D epithelial monolayers and 3D spheroidal aggregates can be understood as an active wetting transition whose physics differs fundamentally from that of passive wetting phenomena. By combining an active polar fluid model with measurements of physical forces as a function of tissue size, contractility, cell-cell and cell-substrate adhesion, and substrate stiffness, we show that the wetting transition results from the competition between traction forces and contractile intercellular stresses. This competition defines a new intrinsic lengthscale that gives rise to a critical size for the wetting transition in tissues, a striking feature that has no counterpart in classical wetting. Finally, we show that active shape fluctuations are dynamically amplified during tissue dewetting. Overall, we conclude that tissue spreading constitutes a prominent example of active wetting --- a novel physical scenario that may explain morphological transitions during tissue morphogenesis and tumor progression

    Severe skin reaction secondary to concomitant radiotherapy plus cetuximab

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    The therapeutic use of monoclonal antibodies against the epidermal growth factor receptor (EGFR) is specifically associated with dermatologic reactions of variable severity. Recent evidence suggests superiority of the EGFR inhibitor (EGFRI) cetuximab plus radiotherapy compared to radiotherapy alone in patients with squamous cell carcinoma of the head and neck. Although not documented in a study population, several reports indicate a possible overlap between radiation dermatitis and the EGFRI-induced skin rash. We here present a case of severe skin reaction secondary to the addition of cetuximab to radiotherapy
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