163 research outputs found

    Callose deposition and symplastic connectivity are regulated prior to lateral root emergence.

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    Root growth is critical for the effective exploitation of the rhizosphere and productive plant growth. Our recent work(1) showed that root architecture was dependent upon the degree of symplastic connectivity between neighboring cells during the specification of lateral root primordia and was affected by genes regulating callose deposition at plasmodesmata (PD). Here we provide additional evidence that both symplastic connectivity and callose are also important during the later phase of lateral root development: emergence. Callose immunolocalization assays indicated that transient symplastic isolation of the primordium occur immediately prior to emergence through the overlaying tissues to produce the mature lateral root.(1) Here we could corroborate these results by analyzing the mobility of a symplastic tracer and the expression of PD genes in lateral roots and in response to auxins. Moreover, we show that altering callose deposition affects the number of emerged lateral roots suggesting that PD regulation is important for emergence

    First record of the Neolicaphrium recens Frenguelli, 1921 (Mammalia, Litopterna) in the Pleistocene of Santiago del Estero Province, Argentina

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    The first record of the Neolicaphrium recens Frenguelli, 1921 (Mammalia, Litopterna) from Pleistocene deposits of the Río Dulce, Rio Hondo Department, Santiago del Estero Province, Argentina, is reported. The morphology and morphometry observed in the specimen MPAT073 is coincident with the diagnostic characteristics of that species. This finding represents the northernmost and westernmost record of the species, and thus extends its geographical distribution. Geological data suggest that the material comes from a still unnamed Pleistocene stratigraphic unit. © 2017, Universidade de Sao Paulo. All rights reserved.Se presenta el primer registro del proterotérido Neolicaphrium recens Frenguelli, 1921 (Mammalia, Litopterna) en sedimentos del Río Dulce, Departamento Río Hondo, provincia de Santiago del Estero, Argentina. Los rasgos morfológicos y morfométricos observados en el espécimen MPAT073 son coincidentes con los caracteres indicados como diagnósticos de esa especie. Este hallazgo representa el registro más septentrional y occidental reportado hasta el momento para esta especie, y extiende su rango de distribución geográfica conocida. Los datos geológicos disponibles sugieren que el material proviene de una unidad todavía innominada del Pleistoceno.Facultad de Ciencias Naturales y Muse

    Use of water troughs by wild rabbits (Oryctolagus cuniculus) in a farmland area of north–west Spain

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    Uso de bebederos por parte del conejo de monte (Oryctolagus cuniculus) en un paisaje agrícola en el noroeste de EspañaEn la península Ibérica, los bebederos son una herramienta de gestión de hábitat muy frecuente para incrementar las densidades de especies de caza menor, aunque el comportamiento de ingestión de agua de las especies “diana” no se ha estudiado en profundidad, como es el caso del conejo de monte (Oryctolagus cuniculus). Estudiamos el uso de bebederos por parte de conejos de monte durante 228 períodos de una semana en tres períodos consecutivos (junio–octubre) de 2008, 2009 y 2010 en un paisaje agrícola de noroeste de España, utilizando cámaras de fototrampeo. Los conejos utilizaron el 43% de los bebederos y se observó un número significativamente mayor de conejos bebiendo en bebederos rodeados por cobertura vegetal en comparación con bebederos situados en campos abiertos sin dicha cobertura vegetal. La mayoría de los conejos que bebieron fueron fotografiados de julio a septiembre (98%), si bien la utilización de bebederos no se relacionó claramente con la climatología. Los conejos bebieron principalmente durante la mañana (52% de los conejos) no tanto durante la tarde y noche, y raramente durante el mediodía. Los conejos se fotografiaron junto con perdices rojas (Alectoris rufa) en el 6% de las fotografías. Estos hallazgos sugieren que los bebederos son útiles para el conejo y otras especies con necesidades hídricas similares y que debieran ser colocados cerca de zonas con cobertura vegetal arbustiva.Installation of water troughs is a common approach to increase densities of small game species in the Iberian peninsula but little is known about the watering patterns of target species, such as the wild rabbit (Oryctolagus cuniculus). Using camera trapping, we monitored the use of water troughs by wild rabbits over 228 weeks in three consecutive periods, from June to October in 2008, 2009 and 2010, on farmland in north–west Spain. Wild rabbits used 43% of the water troughs. A significantly higher number of rabbits were observed drinking at troughs surrounded by shrub cover than at those in open fields. Most drinking events were recorded from July to September (98%), though the use of water troughs was not clearly related to weather. Wild rabbits drank mainly during the morning (52% of rabbits), less so in the evening and at night, and rarely in the afternoon. Wild rabbits were photographed together with red–legged partridges (Alectoris rufa) in 6% of photographs. These findings suggest water troughs are useful for species such as wild rabbits and should be allocated close to shrub areas.Uso de bebederos por parte del conejo de monte (Oryctolagus cuniculus) en un paisaje agrícola en el noroeste de EspañaEn la península Ibérica, los bebederos son una herramienta de gestión de hábitat muy frecuente para incrementar las densidades de especies de caza menor, aunque el comportamiento de ingestión de agua de las especies “diana” no se ha estudiado en profundidad, como es el caso del conejo de monte (Oryctolagus cuniculus). Estudiamos el uso de bebederos por parte de conejos de monte durante 228 períodos de una semana en tres períodos consecutivos (junio–octubre) de 2008, 2009 y 2010 en un paisaje agrícola de noroeste de España, utilizando cámaras de fototrampeo. Los conejos utilizaron el 43% de los bebederos y se observó un número significativamente mayor de conejos bebiendo en bebederos rodeados por cobertura vegetal en comparación con bebederos situados en campos abiertos sin dicha cobertura vegetal. La mayoría de los conejos que bebieron fueron fotografiados de julio a septiembre (98%), si bien la utilización de bebederos no se relacionó claramente con la climatología. Los conejos bebieron principalmente durante la mañana (52% de los conejos) no tanto durante la tarde y noche, y raramente durante el mediodía. Los conejos se fotografiaron junto con perdices rojas (Alectoris rufa) en el 6% de las fotografías. Estos hallazgos sugieren que los bebederos son útiles para el conejo y otras especies con necesidades hídricas similares y que debieran ser colocados cerca de zonas con cobertura vegetal arbustiva

    Current-Driven Conformational Changes, Charging and Negative Differential Resistance in Molecular Wires

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    We introduce a theoretical approach based on scattering theory and total energy methods that treats transport non-linearities, conformational changes and charging effects in molecular wires in a unified way. We apply this approach to molecular wires consisting of chain molecules with different electronic and structural properties bonded to metal contacts. We show that non-linear transport in all of these systems can be understood in terms of a single physical mechanism and predict that negative differential resistance at high bias should be a generic property of such molecular wires.Comment: 9 pages, 4 figure

    First record of the Neolicaphrium recens Frenguelli, 1921 (Mammalia, Litopterna) in the Pleistocene of Santiago del Estero Province, Argentina

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    The first record of the Neolicaphrium recens Frenguelli, 1921 (Mammalia, Litopterna) from Pleistocene deposits of the Río Dulce, Rio Hondo Department, Santiago del Estero Province, Argentina, is reported. The morphology and morphometry observed in the specimen MPAT073 is coincident with the diagnostic characteristics of that species. This finding represents the northernmost and westernmost record of the species, and thus extends its geographical distribution. Geological data suggest that the material comes from a still unnamed Pleistocene stratigraphic unit. © 2017, Universidade de Sao Paulo. All rights reserved.Se presenta el primer registro del proterotérido Neolicaphrium recens Frenguelli, 1921 (Mammalia, Litopterna) en sedimentos del Río Dulce, Departamento Río Hondo, provincia de Santiago del Estero, Argentina. Los rasgos morfológicos y morfométricos observados en el espécimen MPAT073 son coincidentes con los caracteres indicados como diagnósticos de esa especie. Este hallazgo representa el registro más septentrional y occidental reportado hasta el momento para esta especie, y extiende su rango de distribución geográfica conocida. Los datos geológicos disponibles sugieren que el material proviene de una unidad todavía innominada del Pleistoceno.Facultad de Ciencias Naturales y Muse

    Decoherence in elastic and polaronic transport via discrete quantum states

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    Here we study the effect of decoherence on elastic and polaronic transport via discrete quantum states. The calculations are performed with the help of nonperturbative computational scheme, based on the Green's function theory within the framework of polaron transformation (GFT-PT), where the many-body electron-phonon interaction problem is mapped exactly into a single-electron multi-channel scattering problem. In particular, the influence of dephasing and relaxation processes on the shape of the electrical current and shot noise curves is discussed in detail under the linear and nonlinear transport conditions.Comment: 11 pages, 3 figure

    New onset of loss of smell or taste in household contacts of home-isolated SARS-CoV-2-positive subjects

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    Purpose: To estimate the prevalence of smell or taste impairment in household contacts of mildly symptomatic home-isolated SARS-CoV-2-positive patients. Methods: Cross-sectional study based on ad hoc questions. Results: Of 214 mildly symptomatic COVID-19 patients managed at home under self-isolation, 179 reported to have at least one household contact, with the total number of no study participants contacts being 296. Among 175 household contacts not tested for SARS-CoV-2 infection, 67 (38.3%) had SARS-CoV-2 compatible symptoms, 39 (22.3%) had loss of smell or taste with 7 (4.0%) having loss of smell or taste in the absence of other symptoms. The prevalence of smell or taste impairment was 1.5% in patients tested negative compared to 63.0% of those tested positive for SARS-CoV-2 (p < 0.001). Conclusion: Smell or taste impairment are quite common in not-tested household contacts of mildly symptomatic home-isolated SARS-CoV-2-positive patients. This should be taken into account when estimating the burden of loss of sense of smell and taste during COVID-19 pandemic, and further highlights the value of loss of sense of smell and taste as a marker of infection

    How grossone can be helpful to iteratively compute negative curvature directions

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    We consider an iterative computation of negative curvature directions, in large scale optimization frameworks. We show that to the latter purpose, borrowing the ideas in [1, 3] and [4], we can fruitfully pair the Conjugate Gradient (CG) method with a recently introduced numerical approach involving the use of grossone [5]. In particular, though in principle the CG method is well-posed only on positive definite linear systems, the use of grossone can enhance the performance of the CG, allowing the computation of negative curvature directions, too. The overall method in our proposal significantly generalizes the theory proposed for [1] and [3], and straightforwardly allows the use of a CG-based method on indefinite Newton’s equations

    Human Mas-related G protein-coupled receptors-X1 induce chemokine receptor 2 expression in rat dorsal root ganglia neurons and release of chemokine ligand 2 from the human LAD-2 mast cell line

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    Primate-specific Mas-related G protein-coupled receptors-X1 (MRGPR-X1) are highly enriched in dorsal root ganglia (DRG) neurons and induce acute pain. Herein, we analyzed effects of MRGPR-X1 on serum response factors (SRF) or nuclear factors of activated T cells (NFAT), which control expression of various markers of chronic pain. Using HEK293, DRG neuron-derived F11 cells and cultured rat DRG neurons recombinantly expressing human MRGPR-X1, we found activation of a SRF reporter gene construct and induction of the early growth response protein-1 via extracellular signal-regulated kinases-1/2 known to play a significant role in the development of inflammatory pain. Furthermore, we observed MRGPR-X1-induced up-regulation of the chemokine receptor 2 (CCR2) via NFAT, which is considered as a key event in the onset of neuropathic pain and, so far, has not yet been described for any endogenous neuropeptide. Up-regulation of CCR2 is often associated with increased release of its endogenous agonist chemokine ligand 2 (CCL2). We also found MRGPR-X1-promoted release of CCL2 in a human connective tissue mast cell line endogenously expressing MRGPR-X1. Thus, we provide first evidence to suggest that MRGPR-X1 induce expression of chronic pain markers in DRG neurons and propose a so far unidentified signaling circuit that enhances chemokine signaling by acting on two distinct yet functionally co-operating cell types. Given the important role of chemokine signaling in pain chronification, we propose that interruption of this signaling circuit might be a promising new strategy to alleviate chemokine-promoted pain
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