Efecto de la aplicación del herbicida metsulfuron metil en mezcla con glifosato, en el establecimiento de plantaciones de Eucalyptus globulus Labill

- Bravo, T. Forestal Mininco S.A., Los Angeles, Chile. - Muñoz, F. ;Sánchez-Olate, M. Facultad de Ciencias Forestales, Universidad de Concepción. Casilla 60-C, Concepción, Chile.La rentabilidad de las plantaciones de Eucalyptus globulus está en relación, entre otros factores, con la adecuada implementación de un programa de control de malezas. Según las condiciones en la cual se desarrolla la plantación, la aplicación de herbicidas antes de la plantación es una adecuada alternativa de control de las malezas. Para ello, se ha utilizado ampliamente mezcla de herbicida persistente en el suelo (Simazina) en combinación con un herbicida sistémico de amplio espectro (Glifosato). Debido al cuestionamiento ambiental del herbicida Simazina, se estudió su reemplazo por el herbicida Metsulfuron-metil. El ensayo se estableció en el año 2005 en un predio ubicado en la comuna de Mulchen, de propiedad de la empresa Forestal y Agrícola Monte Aguila S.A., de acuerdo a un diseño factorial de dos factores. Un factor es el herbicida Metsulfuron-metil en tres niveles (dosis de 50, 75 y 100 g/ha) y el otro, tiempo de carencia de plantación en dos niveles (15 y 30 días de aplicación antes de la plantación). La aplicación de Metsulfuron-metil se realizó en mezcla con Glifosato. Las variables respuesta fueron diámetro a la altura del cuello, altura y sobrevivencia de las plantas. A los 8 meses de aplicados los tratamientos hubo diferencias significativas en el crecimiento de las plantas de Eucalyptus globulus, no así, en su sobrevivencia

Analysis of Serve and Serve-Return Strategies in Elite Male and Female Padel

This aim of this study was to analyze serve and return statistics in elite padel players regarding courtside and gender. The sample contained 668 serves and 600 returns of serves from 14 matches (7 male and 7 female) of the 2019 Masters Finals World Padel Tour. Variables pertaining to serve (number, direction, court side and effectiveness), return of serve (direction, height, stroke type and effectiveness) and point outcome were registered through systematic observation. The main results showed that the serving pair had an advantage in rallies, under 8 shots in women and under 12 shots in men. Statistical differences according to gender and court side were found. Female players execute more backhand and cross-court returns and use more lobs than men. On the right court, serves are more frequently aimed at the "T" and more down the line returns are executed when compared to the left side. Such knowledge could be useful to develop appropriate game strategies and to design specific training exercises based on actual competition context

An X-ray study of the SNR G344.7-0.1 and the central object CXOU J170357.8-414302

Aims. We report results of an X-ray study of the supernova remnant (SNR) G344.7-0.1 and the point-like X-ray source located at the geometrical center of the SNR radio structure. Methods. The morphology and spectral properties of the remnant and the central X-ray point-like source were studied using data from the XMM-Newton and Chandra satellites. Archival radio data and infrared Spitzer observations at 8 and 24 $\mu$m were used to compare and study its multi-band properties at different wavelengths. Results. The XMM-Newton and Chandra observations reveal that the overall X-ray emission of G344.7-0.1 is extended and correlates very well with regions of bright radio and infrared emission. The X-ray spectrum is dominated by prominent atomic emission lines. These characteristics suggest that the X-ray emission originated in a thin thermal plasma, whose radiation is represented well by a plane-parallel shock plasma model (PSHOCK). Our study favors the scenario in which G344.7-0.1 is a 6 x 10^3 year old SNR expanding in a medium with a high density gradient and is most likely encountering a molecular cloud on the western side. In addition, we report the discovery of a soft point-like X-ray source located at the geometrical center of the radio SNR structure. The object presents some characteristics of the so-called compact central objects (CCO). However, its neutral hydrogen absorption column (N_{H}) is inconsistent with that of the SNR. Coincident with the position of the source, we found infrared and optical objects with typical early-K star characteristics. The X-ray source may be a foreground star or the CCO associated with the SNR. If this latter possibility were confirmed, the point-like source would be the farthest CCO detected so far and the eighth member of the new population of isolated and weakly magnetized neutron stars.Comment: 9 pages, 8 figures, accepted for publication in Astronomy and Astrophysics. Higher resolution figures can be seen on A&

Axial turbine flow path design for concentrated solar power plants operating with CO2 blends

The utilisation of certain blends based on supercritical CO (sCO), namely CO/TiCl, CO/C and CO/SO, have been found to be promising for enhancing the performance of power cycles for Concentrated Solar Power (CSP) applications; allowing for up to a 6% enhancement in cycle efficiency with respect to a simple recuperated CO cycle, depending upon the nature of the used blend and the cycle configuration of choice. This paper presents an investigation of the impact of adopting these sCO-based blends on the flow path design for a multi-stage axial turbine whilst accounting for aerodynamic, mechanical and rotordynamic considerations. This includes assessing the sensitivity of the turbine design to selected working fluid and imposed optimal cycle conditions. Ultimately, this study aims to provide the first indication that a high-efficiency turbine can be achieved for a large-scale axial turbine operating with these non-conventional working fluids and producing power in excess of 120 MW. To achieve this aim, mean-line aerodynamic design is integrated with mechanical and rotordynamic constraints, specified based on industrial experience, to ensure technically feasible solutions with maximum aerodynamic efficiency. Different turbine flow path designs have been produced for three sCO blends under different cycle boundary conditions. Specifically, flow paths have been obtained for optimal cycle configurations at five different molar fractions and two different turbine inlet pressure and temperature levels of 250 & 350 bar and 550 & 700 °C respectively. A total-to-total turbine efficiency in excess of 92% was achieved, which is considered promising for the future of CO plants. The highest efficiencies are achieved for designs with a large number of stages, corresponding to reduced hub diameters due to the need for a fixed synchronous rotational speed. The large number of stages is contrary to existing sCO turbine designs, but it is found that an increase from 4 to 14 stages can increase the efficiency by around 5%. Ultimately, based on the preliminary cost analysis results, the designs with a large number of stages showed to be financially feasible compared to the designs with a small number of stages