786 research outputs found

    A laser triangulation sensor for vibrational structural analysis and diagnostics

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    The industrial progress has reached a level in which it is necessary to understand the behavior of mechanical components and to monitor their conditions without disassembling them. Nowadays, a suitable methodology is based on vibrational analysis usually performed through acceleration signals measured directly on the system to be tested. However, in the last years, the industrial scenario has deeply changed due to the need for time reduction, in particular, for the control operations at the end of the productive line. The genuine methods based on acceleration measurements, for example, through piezoelectric accelerometers, came into conflict with the industrial need as the sensors used for the quality control have to be easily and fastly mounted and unmounted. A valid alternative is represented by the exploitation of laser triangulation sensors that are able to measure the dynamic displacement in a contactless way, strongly reducing the (un)mounting time. The target of this paper is to highlight pros and cons of the contactless displacement analysis through laser triangulation sensors with respect to the contact one through genuine accelerometers by means of a comparison between the results obtained both for experimental modal analysis and vibrational diagnostics of rotating machines

    Two QTLs govern the resistance to Sclerotinia minor in an interspecific peanut RIL population

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    Sclerotinia blight is a soilborne disease caused by Sclerotinia minor Jagger and can produce severe decrease in yield. Cultural management strategies and chemical treatment are not completely effective; therefore, growing peanut-resistant varieties is likely to be the most effective control method for this disease. Sclerotinia blight resistance has been identified in wild Arachis species and further transferred to peanut elite cultivars. To identify the genome regions conferring Sclerotinia blight resistance within a tetraploid genetic background, this study evaluated a population of recombinant inbred lines (RIL) with introgressed genes from three wild diploid species: A. cardenasii, A. correntina, and A. batizocoi. Two consistent quantitative trait loci (QTLs), qSbIA04 and qSbIB04 located on chromosomes A04 and B04, respectively, were identified. The QTL qSbIA04 was mapped at 56.39 cM explaining 29% of the phenotypic variance and qSbIB04 was mapped at 13.38 cM explaining 22% of the overall phenotypic variance

    Identificación de Germoplasma de maní de criadero el Carmen tolerante a la sequia: aspectos bioquímicos y rendimiento

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    PosterLa sequía estacional es un estrés ambiental que genera pérdidas de rendimiento de alrededor del 30% en el cultivo de maní (Arachis hypogaea) en la Provincia de Córdoba. Una de las estrategias para reducirlas es el desarrollo de nuevas variedades comerciales con mayor tolerancia a la sequía. Desde el año 2016 se está desarrollando un sistema de identificación de materiales tolerantes a sequía provenientes de la colección de germoplasma de Criadero El Carmen, empleando un método estandarizado bajo condiciones controladas, que reduce los tiempos de evaluación al realizarse en etapa vegetativa. Se emplean las respuestas relacionadas al balance osmótico y la fotosíntesis como marcadores fisiológicos que permiten monitorear la tolerancia de los materiales de interés. Previamente, se evaluaron diferentes parámetros bioquímicos registrados en distintos ensayos mediante un análisis de componentes principales (PCA), lo que permitió determinar que los contenidos de prolina, carotenoides y azucares están asociados a una mayor tolerancia a la sequía en estadios tempranos del desarrollo vegetativo. El proyecto tiene como objetivo identificar germoplasma de maní tolerante a la sequía mediante un sistema estandarizado rápido a emplearse en etapas vegetativas bajo condiciones controladas y su validación posterior en la etapa reproductiva.Instituto de Fisiología y Recursos Genéticos VegetalesFil: Guzzo, María Carla. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Fisiología y Recursos Genéticos Vegetales; ArgentinaFil: Posada, G. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Fisiología y Recursos Genéticos Vegetales; ArgentinaFil: Costamagna, C. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Fisiología y Recursos Genéticos Vegetales; ArgentinaFil: Soave, S.J. Criadero El Carmen. Gral. Cabrera, Córdoba; ArgentinaFil: Soave, J.H. Criadero El Carmen. Gral. Cabrera, Córdoba; ArgentinaFil: Buteler, M.I. Criadero El Carmen. Gral. Cabrera, Córdoba; ArgentinaFil: Monteoliva, Mariela Ines. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Fisiología y Recursos Genéticos Vegetales; ArgentinaFil: Monteoliva, Mariela Ines. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Estudios Agropecuarios (UDEA); Argentin

    Relative abundance of the Burrowing Parrot (Cyanoliseus patagonus) in Buenos Aires Province and nearby areas of La Pampa and Río Negro, Argentina

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    El Loro Barranquero (Cyanoliseus patagonus) tiene una amplia distribución en el sur de América del Sur, aunque su abundancia es variable. La especie fue considerada plaga para la agricultura (pese a no existir estudios que lo avalen) y ha soportado presión de caza plaguicida y de captura de individuos para el comercio de mascotas. Actualmente, solo la provincia de Buenos Aires sigue considerándola como plaga. Sin embargo, no se cuenta con estudios sobre la abundancia relativa de la especie en esta región. Entre 2003 y 2006 se estimó su abundancia en la provincia de Buenos Aires y las zonas limítrofes de Río Negro y La Pampa. Se recorrieron 3156 km, subdivididos en seis tramos, en los cuales se registró estacionalmente la presencia del Loro Barranquero en 168 transectas de 5 km de longitud. Además, se contaron individuos en dos dormideros. Se detectaron 765 individuos en total, con una abundancia promedio de 0.24 individuos/ km. Sin embargo, todas las detecciones se efectuaron en solo 312 km de recorrido, concentrándose la mayoría en tres áreas del sudoeste bonaerense: cerca de Pedro Luro, en la cuenca del río Quequén Salado y en la Comarca Serrana de Sierra de la Ventana. Los valores de abundancia relativa y la distribución observada indican que la especie no se comporta como plaga.The Burrowing Parrot (Cyanoliseus patagonus) is a widely distributed species in southern South America, with a variable abundance along its range. Due to its official designation as crop pest (without any objective studies that corroborated the truth of this legal status), this species has been heavily persecuted and captured for the pet trade. Currently, only Buenos Aires Province considers this species a crop pest. Nevertheless, there are no data on its relative abundance for this region. Between 2003 and 2006, we carried out a study on the abundance of the Burrowing Parrot in Buenos Aires Province and adjacent areas in the provinces of Río Negro and La Pampa. We surveyed 3156 km, divided in six sectors, where the presence of the species was seasonally recorded along 168 transects (5 km long each). Additionally, we gathered abundance data from two large roosting places. We observed a total of 765 individuals, with a mean abundance of 0.24 individuals/km. However, all individuals were observed in only 312 km, most of them restricted to three areas in southwestern Buenos Aires: near Pedro Luro city, Quequén Salado river basin, and the Comarca Serrana of Sierra de la Ventana. Observed relative abundance and distribution indicate that the Burrowing Parrot cannot be consider a crop pest

    Symbolic dynamics for the NN-centre problem at negative energies

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    We consider the planar NN-centre problem, with homogeneous potentials of degree -\a<0, \a \in [1,2). We prove the existence of infinitely many collisions-free periodic solutions with negative and small energy, for any distribution of the centres inside a compact set. The proof is based upon topological, variational and geometric arguments. The existence result allows to characterize the associated dynamical system with a symbolic dynamics, where the symbols are the partitions of the NN centres in two non-empty sets

    Thirty Years with EoS/G<sup>E</sup> Models - What Have We Learned?

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    The ALICE Zero Degree Calorimeters

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    In the ALICE experiment at Cern LHC, a set of hadron calorimeters will be used to determine the centrality of the Pb-Pb collision. The spectator protons and neutrons, will be separated from the ion beams, using the separator magnet (D1) of the LHC beam optics and respectively detected by a proton (ZP) and a neutron (ZN) "Zero-degree Calorimeter" (ZDC). The detectors will be placed in front of the separator D2 magnet, 115 meters away from the beam intersection point. The ZDCs are quartz-fiber spaghetti calorimeters that exploit the Cherenkov light produced by the shower particles in silica optical fibers.This technique offers the advantages of high radiation hardness (up to several Grad), fast response and reduced lateral dimension of the detectable shower. In addition, quartz-fiber calorimeters are intrinsically insensitive to radio-activation background, which produces particles below the Cherenkov threshold.The ALICE ZDC should have an energy resolution comparable with the intrinsic energy fluctuations, which range from about 20 0.000000or central events to about 5 0.000000or peripheral ones, according to simulations that use HIJING as event generator. The fiber-to-absorber filling ratio must be chosen as a good compromise between the required energy resolution and the fiber cost.The design of the proposed calorimeter will be discussed, together with the expected performances. Whenever possible, the simulated results will be compared with the experimental ones, obtained with the built prototypes and with the NA50 ZDC, which can be considered as a working prototype for the ALICE neutron calorimeter

    Postoperative respiratory failure in liver transplantation: Risk factors and effect on prognosis

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    Background :Postoperative respiratory failure (PRF, namely mechanical ventilation &gt;48 hours) significantly affects morbidity and mortality in liver transplantation (LTx). Previous studies analyzed only one or two categories of PRF risk factors (preoperative, intraoperative or postoperative ones). The aims of this study were to identify PRF predictors, to assess the length of stay (LoS) in ICU and the 90-day survival according to the PRF in LTx patients. Methods: Two classification approaches were used: systematic classification (recipient-related preoperative factors; intraoperative factors; logistic factors; donor factors; postoperative ICU factors; postoperative surgical factors) and patient/organ classification (patient-related general factors; native-liver factors; new-liver factors; kidney factors; heart factors; brain factors; lung factors). Two hundred adult non-acute patients were included. Missing analysis was performed. The competitive role of each factor was assessed. Results: PRF occurred in 36.0% of cases. Among 28 significant PRF predictors at univariate analysis, 6 were excluded because of collinearity, 22 were investigated by ROC curves and by logistic regression analysis. Recipient age (OR = 1.05; p = 0.010), female sex (OR = 2.75; p = 0.018), Model for End-Stage Liver Disease (MELD, OR = 1.09; p&lt;0.001), restrictive lung pattern (OR = 2.49; p = 0.027), intraoperative veno-venous bypass (VVBP, OR = 3.03; p = 0.008), pre-extubation PaCO 2 (OR = 1.11; p = 0.003) and Model for Early Allograft Function (MEAF, OR = 1.37; p&lt;0.001) resulted independent PRF risk factors. As compared to patients without PRF, the PRF-group had longer LoS (10 days IQR 7-18 versus 5 days IQR 4-7, respectively; p&lt;0.001) and lower day-90 survival (86.0% versus 97.6% respectively, p&lt;0.001). Conclusion: In conclusion, MELD, restrictive lung pattern, surgical complexity as captured by VVBP, pre-extubation PaCO 2 and MEAF are the main predictors of PRF in non-acute LTx patients

    Etiologia de manchas de sementes de cultivares de arroz de sequeiro no Centro-Oeste brasileiro.

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    O presente trabalho teve o objetivo de conhecer os fungos que mancham sementes de arroz, estudando a importância de cada um, sua frequência e nível de incidência, baseando-se na correlação da quantidade de cada fungo com a quantidade de mancha de semente de arroz de sequeiro do Centro-Oeste brasileiro
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