959 research outputs found

    DESCRIPCIÓN ESTRUCTURAL Y FUNCIONAL DE CAÍDA PREMATURA DE FRUTOS DE Vanilla planifolia Jacks. ex Andrew

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    A partir de 2005 se registró disminución de 90% de la producción de vainilla (Vanilla planifolia Jacks. ex Andrew), asociada a caída de frutos inmaduros. Esto provocó pérdidas económicas considerables en todos los eslabones del sistema producto vainilla a nivel nacional (México)

    Boundedness, compactness and Schatten-class membership of weighted composition operators

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    The boundedness and compactness of weighted composition operators on the Hardy space H2{\mathcal H}^2 of the unit disc is analysed. Particular reference is made to the case when the self-map of the disc is an inner function. Schatten-class membership is also considered; as a result, stronger forms of the two main results of a recent paper of Gunatillake are derived. Finally, weighted composition operators on weighted Bergman spaces A2α(D)\mathcal{A}^2 \alpha(\mathbb{D}) are considered, and the results of Harper and Smith, linking their properties to those of Carleson embeddings, are extended to this situation.Comment: 12 page

    Influence of Varying Quantitative Fecal Immunochemical Test Positivity Thresholds on Colorectal Cancer Detection: A Community-Based Cohort Study.

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    The fecal immunochemical test (FIT) is commonly used for colorectal cancer (CRC) screening. Despite demographic variations in stool hemoglobin concentrations, few data exist regarding optimal positivity thresholds by age and sex. To identify programmatic (multitest) FIT performance characteristics and optimal FIT quantitative hemoglobin positivity thresholds in a large, population-based, screening program. Retrospective cohort study. Kaiser Permanente Northern and Southern California. Adults aged 50 to 75 years who were eligible for screening and had baseline quantitative FIT results (2013 to 2014) and 2 years of follow-up. Nearly two thirds (411 241) had FIT screening in the previous 2 years. FIT programmatic sensitivity for CRC and number of positive test results per cancer case detected, overall and by age and sex. Of 640 859 persons who completed a baseline FIT and were followed for 2 years, 481 817 (75%) had at least 1 additional FIT and 1245 (0.19%) received a CRC diagnosis. Cancer detection (programmatic sensitivity) increased at lower positivity thresholds, from 822 in 1245 (66.0%) at 30 µg/g to 925 (74.3%) at 20 µg/g and 987 (79.3%) at 10 µg/g; the number of positive test results per cancer case detected increased from 43 at 30 µg/g to 52 at 20 µg/g and 85 at 10 µg/g. Reducing the positivity threshold from 20 to 15 µg/g would detect 3% more cancer cases and require 23% more colonoscopies. At the conventional FIT threshold of 20 µg/g, programmatic sensitivity decreased with increasing age (79.0%, 73.4%, and 68.9% for ages 50 to 59, 60 to 69, and 70 to 75 years, respectively; P = 0.009) and was higher in men than women (77.0% vs. 70.6%; P = 0.011). Information on advanced adenoma was lacking. Increased cancer detection at lower positivity thresholds is counterbalanced by substantial increases in positive tests. Tailored thresholds may provide screening benefits that are more equal among different demographic groups, depending on local resources. National Cancer Institute

    New molecular approaches in adipogenesis regulation: The connexin 43 role

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    Indexación: Scopus; Redalyc.La prevalencia de la obesidad a nivel mundial se ha incrementado rápidamente durante los últimos años debido principalmente a los cambios en el estilo de vida de la población con un aumento significativo en el consumo de energía y disminución de los niveles de actividad física. Es por esto que la comunidad científica está interesada en comprender de forma más profunda los mecanismos que regulan la fisiopatología de la obesidad. Dentro de los diferentes blancos de estudio se encuentra la adipogénesis, cuyo entendimiento es fundamental para comprender el desarrollo de la obesidad y las patologías asociadas a esta. Recientemente ha surgido importantes evidencias que involucran a la proteína de canales de “Gap Junction” conexina 43 (Cx43) en la regulación de los procesos relacionados con adipogénesis, cuyo papel es básicamente anti-adipogénico, sin embargo, nuevas funciones de Cx43 en la regulación de la formación del tejido adiposo siguen descubriéndose.The global prevalence of obesity has been increased rapidly over the past few years mainly due to changes in the lifestyle of the population with a significant increase in energy consumption and decreased levels of physical activity. As a result, the scientific community is interested in a deeper understanding of the mechanisms that regulate the pathophysiology of obesity. In this context, adipogenesis process is an important target of study to understand the obesity and associated pathologies. Recently has been emerged important evidence that involve gap junction channel protein connexin 43 (Cx43) in the regulation of processes related to adipogenesis, whose role is fundamentally anti-adipogenic. However, new functions of Cx43 in the regulation of adipose tissue function also continued to emerge.http://www.redalyc.org/articulo.oa?id=5594990800

    Efecto de ciclos hidratación-deshidratación durante la germinación en semillas del género ferocactus

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    El proceso de germinación para la planta es una etapa arriesgada durante su ciclo de vida, en especial para aquellas pertenecientes a zonas áridas como ocurre con las cactáceas, que pasan por períodos discontinuos de hidratación, por lo que, la memoria de hidratación es un proceso vital y una adaptación natural para estas plantas. En el presente trabajo se utilizaron las semillas de E. grusonii, F. clausen, F. peninsulae, F. pilosus, F. recurvus; de las cuales únicamente la última de estas evidenció dicho fenómeno al expresar curvas de germinación similares a F. peninsulae, planta que en el 2014 fue confirmada la presencia de este proceso; la temperatura, además del agua, fue un factor de restricción en los ensayos, al someter a las especies a distintas temperaturas que afectaron en mayor medida la germinación conforme esta disminuyó.The germination process for the plant is a risky stage during its life cycle, especially for those belonging to arid areas such as cacti, which go through discontinuous periods of hydration, so hydration memory is a process vital and a natural adaptation for these plants. In the present work the seeds of E. grusonii, F. clausen, F. peninsulae, F. pilosus, F. recurvus were used; of which only the last of these evidenced this phenomenon by expressing germination curves similar to F. peninsulae, a plant that in 2014 was confirmed the presence of this process; temperature, in addition to water, was a restriction factor in the tests, by subjecting the species to different temperatures that affected germination to a greater extent as it decreased

    Oral Melanoacanthoma And Oral Melanotic Macule: A Report Of 8 Cases, Review Of The Literature, And Immunohistochemical Analysis

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    Oral melanoacanthoma (MA) is a rare, benign pigmented lesion, similar to cutaneous MA, characterized by hyperplasia of spinous keratinocytes and dendritic melanocytes. The pathogenesis of oral MA remains uncertain, although its clinical behavior is suggestive of a reactive origin. The most common intraoral sites are the buccal mucosa, lip, palate and gingiva. The average age of presentation is 28 years, mainly in blacks, with a strong female predilection. The oral melanotic macule (MM) is a small, well-circumscribed brown-to-black macule that occurs on the lips and mucous membranes. The etiology is not clear and it may represent a physiologic or reactive process. The average age of presentation is 43 years, with a female predilection. A biopsy is recommended to distinguish these lesions from each other and from other oral melanocytic lesions. We depict four cases each of oral MA and MM, affecting Caucasian and Latin American mestizo patients. The clinicopathological features of these cases reflect its ample spectrum, and to the best of our knowledge, it is the first example of oral MA affecting a Caucasian boy reported in the English literature. Therefore oral MA and MM should be considered in the differential diagnosis of pigmented lesions in the oral mucosa in these populations. © Medicina Oral.125E374E379Mishima, Y., Pinkus, H., Benign mixed tumor of melanocytes and malpighian cells. Melanoacanthoma: Its relationship to Bloch's benign non-nevoid melanoepithelioma (1960) Arch Dermatol, 81, pp. 539-550Buchner, A., Merrell, P.W., Carpenter, W.M., Relative frequency of solitary melanocytic lesions of the oral mucosa (2004) J Oral Pathol Med, 33, pp. 550-557Wright, J.M., Binnie, W.H., Byrd, D.L., Dunsworth, A.R., Intraoral melanoacanthomas (1983) J Periodontol, 54, pp. 107-111Buchner, A., Merrell, P., Hanson, L., Leider, A., Melanocytic hyperplasia of the oral mucosa (1991) Oral Surg, Oral Med Oral Pathol, 71, pp. 58-62Wright, J.M., Intraoral melanoacanthoma: A reactive melanocytic hyperplasia. Case report (1988) J Periodontol, 59, pp. 53-55Tomich, C., Zunt, S.L., Melanoacanthosis (melanoacanthoma) of the oral mucosa (1990) J Dermatol Surg Oncol, 16, pp. 231-236Contreras, E., Carlos, R., Oral melanoacanthosis (melanoachantoma): Report of a case and review of the literature (2005) Med Oral Patol Oral Cir Bucal, 10 (1), pp. 11-12,9-11Fornatora, M.L., Reich, R.F., Haber, S., Solomon, F., Freedman, P.D., Oral melanoacanthomas: A report of 10 cases, review of the literature, and immunohistochemical analysis for HMB-45 reactivity (2003) Am J Dermatopathol, 25, pp. 12-15Matsuoka, L.Y., Glasser, S., Barsky, S., Melanoacanthoma of the lip (1979) Arch Dermatol, 115, pp. 1116-1117Goode, R.K., Crawford, B.E., Callihan, M.D., Neville, B.W., Oral melanoacanthoma. Review of the literature and report of ten cases (1983) Oral Surg Oral Med Oral Pathol, 56, pp. 622-628Scheneider, L.C., Mesa, M.L., Haber, S.M., Melanoacanthoma of the oral mucosa (1981) Oral Surg Oral Med Oral Pathol, 52, pp. 284-287Fatahzadeh, M., Sirois, D.A., Multiple intraoral melanoacanthomas: A case report with unusual findings (2002) Oral Surg Oral Med Oral Pathol Oral Radiol Endod, 94, pp. 54-56Ho, K.K., Dervan, P., O'Loughlin, S., Powell, F.C., Labial melanotic macule: A clinical, histopathologic, and ultrastructural study (1993) J Am Acad of Dermatol, 28, pp. 33-39Sexton, F.M., Maize, J.C., Melanotic macules and melanoacanthomas of the lip. A comparative study with census of the basal melanocyte population (1987) Am J Dermatopathol, 9, pp. 438-444Horlick, H.P., Walther, R.R., Zegarelli, D.J., Silvers, D.N., Eliezri, Y.D., Mucosal melanotic macule, reactive type: A simulation of melanoma (1988) J Am Acad Dermatol, 19, pp. 786-791Buchner, A., Hansen, L.S., Pigmented nevi of the oral mucosa: A clinicopathologic study of 32 new cases and review of 75 cases from the literature: Part I. A clinicopathologic study of 32 new cases (1979) Oral Surg Oral Med Oral Pathol, 48, pp. 131-142Barker, B.F., Carpenter, W.M., Daniels, T.E., Kahn, M.A., Leider, A.S., Lozada-Nur, F., (1997) Oral mucosal melanomas: The WESTOP Banff workshop proceedings, 83, pp. 672-679. , Western Society of Teachers of Oral Pathology. Oral Surg Oral Med Oral Pathol Oral Radiol EndodBarrett, A.W., Raja, A.M., The immunohistochemical identification of human oral mucosal melanocytes (1997) Arch Oral Biol, 42, pp. 77-8

    ‘The Brick’ is not a brick: a comprehensive study of the structure and dynamics of the central molecular zone cloud G0.253+0.016

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    This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society © 2019 The Author(s). Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.In this paper we provide a comprehensive description of the internal dynamics of G0.253+0.016 (a.k.a. ‘the Brick’); one of the most massive and dense molecular clouds in the Galaxy to lack signatures of widespread star formation. As a potential host to a future generation of high-mass stars, understanding largely quiescent molecular clouds like G0.253+0.016 is of critical importance. In this paper, we reanalyse Atacama Large Millimeter Array cycle 0 HNCO J = 4(0, 4) − 3(0, 3) data at 3 mm, using two new pieces of software that we make available to the community. First, SCOUSEPY, a Python implementation of the spectral line fitting algorithm SCOUSE. Secondly, ACORNS (Agglomerative Clustering for ORganising Nested Structures), a hierarchical n-dimensional clustering algorithm designed for use with discrete spectroscopic data. Together, these tools provide an unbiased measurement of the line-of-sight velocity dispersion in this cloud, σvlos,1D=4.4±2.1 km s−1, which is somewhat larger than predicted by velocity dispersion-size relations for the central molecular zone (CMZ). The dispersion of centroid velocities in the plane of the sky are comparable, yielding σvlos,1D/σvpos,1D∼1.2±0.3⁠. This isotropy may indicate that the line-of-sight extent of the cloud is approximately equivalent to that in the plane of the sky. Combining our kinematic decomposition with radiative transfer modelling, we conclude that G0.253+0.016 is not a single, coherent, and centrally condensed molecular cloud; ‘the Brick’ is not a brick. Instead, G0.253+0.016 is a dynamically complex and hierarchically structured molecular cloud whose morphology is consistent with the influence of the orbital dynamics and shear in the CMZ

    Forward pi^0 Production and Associated Transverse Energy Flow in Deep-Inelastic Scattering at HERA

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    Deep-inelastic positron-proton interactions at low values of Bjorken-x down to x \approx 4.10^-5 which give rise to high transverse momentum pi^0 mesons are studied with the H1 experiment at HERA. The inclusive cross section for pi^0 mesons produced at small angles with respect to the proton remnant (the forward region) is presented as a function of the transverse momentum and energy of the pi^0 and of the four-momentum transfer Q^2 and Bjorken-x. Measurements are also presented of the transverse energy flow in events containing a forward pi^0 meson. Hadronic final state calculations based on QCD models implementing different parton evolution schemes are confronted with the data.Comment: 27 pages, 8 figures and 3 table

    Search for Doubly-Charged Higgs Boson Production at HERA

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    A search for the single production of doubly-charged Higgs bosons H^{\pm \pm} in ep collisions is presented. The signal is searched for via the Higgs decays into a high mass pair of same charge leptons, one of them being an electron. The analysis uses up to 118 pb^{-1} of ep data collected by the H1 experiment at HERA. No evidence for doubly-charged Higgs production is observed and mass dependent upper limits are derived on the Yukawa couplings h_{el} of the Higgs boson to an electron-lepton pair. Assuming that the doubly-charged Higgs only decays into an electron and a muon via a coupling of electromagnetic strength h_{e \mu} = \sqrt{4 \pi \alpha_{em}} = 0.3, a lower limit of 141 GeV on the H^{\pm\pm} mass is obtained at the 95% confidence level. For a doubly-charged Higgs decaying only into an electron and a tau and a coupling h_{e\tau} = 0.3, masses below 112 GeV are ruled out.Comment: 15 pages, 3 figures, 1 tabl

    Low Q^2 Jet Production at HERA and Virtual Photon Structure

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    The transition between photoproduction and deep-inelastic scattering is investigated in jet production at the HERA ep collider, using data collected by the H1 experiment. Measurements of the differential inclusive jet cross-sections dsigep/dEt* and dsigmep/deta*, where Et* and eta* are the transverse energy and the pseudorapidity of the jets in the virtual photon-proton centre of mass frame, are presented for 0 < Q2 < 49 GeV2 and 0.3 < y < 0.6. The interpretation of the results in terms of the structure of the virtual photon is discussed. The data are best described by QCD calculations which include a partonic structure of the virtual photon that evolves with Q2.Comment: 20 pages, 5 Figure
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