Assessing the functional relationship between dung beetle traits and dung removal, burial, and seedling emergence

The relationship between biodiversity and ecosystem functioning is often assessed through trait diversity. However, the relationship between traits and functions is typically assumed but seldom tested. We analyze the relationship between dung beetle traits and three ecological functions: dung removal, dung burial, and seedling emergence. We set up a laboratory experiment using nine Scarabaeidae species (three endocoprids, four paracoprids, and two telecoprids). We placed a sexual pair of beetles in each experimental unit, together with a mixture of dung and seeds, and measured the amount of dung removed and buried, burial depth, and the number of emerged seedlings. Sixteen morphological traits related to dung removal and burial were measured in each individual. Results indicate that these traits were related to dung beetle performance in dung removal and burial. Most traits were positively related to dung removal, indicating the existence of a general trait syndrome associated with dung manipulation and digging capability. Dung exploitation strategies did not provide further explanatory power. Seedling emergence showed a negative but weak relationship with dung burial amount and depth and species identity. This implies that specific differences in dung–soil interface activity may be important in secondary seed dispersal by dung beetles.info:eu-repo/semantics/publishedVersio

Traducción y censura en la España franquista

En partant de l’hypothèse selon laquelle le traducteur, fort de son bagage cognitif, interprète le texte qu’il traduit et que la traduction est un phénomène de réécriture, cet article analyse la version espagnole de l’œuvre de la romancière française Sidonie Gabrielle Colette, Claudine à Paris, traduite par Piñas en 1963. L’objectif de cette analyse est de démontrer comment une circonstance historique concrète, la censure imposée par la dictature franquiste, influe sur la traduction.Assuming that the translator, cleverer from his stock of cognitive knowledge, interprets the text he translates, and that translation is a phenomenon of rewriting, this article examines the Spanish version of «Claudine à Paris» by the French novelist Sidonie Gabrielle Colette, translated by Piñas in 1963. The analysis aims at demonstrating how concrete historical circumstances –the censorship imposed by Franco’s dictatorship– influences the work.Partiendo de la premisa de que el traductor interpreta el texto que traduce aportando a esta interpretación su bagaje cognitivo y de que, por tanto, la traducción es un fenómeno de reescritura, este trabajo analiza la versión española de la novela Claudine à Paris, de la escritora francesa Sidonie Gabrielle Colette, traducida por Piñas en 1963, con el fin de demostrar cómo una circunstancia histórica concreta, la censura impuesta por la dictadura franquista, incide sobre el trabajo de traducción

Power console development for NASA's electric propulsion outreach program

NASA LeRC is developing a 30 cm diameter xenon ion thruster for auxiliary and primary propulsion applications. To maximize expectations for user-acceptance of ion propulsion technology, NASA LeRC, through their Electric Propulsion Outreach Program, is providing sectors of industry with portable power consoles for operation of 5 KW-class xenon ion thrusters. This power console provides all necessary functions to permit thruster operations over a 0.5-5 KW envelope under both manual and automated control. These functions include the following: discharge, cathode heater, neutralizer keeper, and neutralizer heater currents, screen and accelerator voltages, and a gas feed system to regulate and control propellant flow to the thruster. An electronic circuit monitors screen and accelerator currents and controls arcing events. The power console was successfully integrated with the NASA 30 cm thruster

Critical boron-doping levels for generation of dislocations in synthetic diamond

Defects induced by boron doping in diamond layers were studied by transmission electron microscopy. The existence of a critical boron doping level above which defects are generated is reported. This level is found to be dependent on the CH4 /H2 molar ratios and on growth directions. The critical boron concentration lied in the 6.5–17.0 X 10 20 at/cm3 range in the direction and at 3.2 X 1021 at/cm 3 for the one. Strain related effects induced by the doping are shown not to be responsible. From the location of dislocations and their Burger vectors, a model is proposed, together with their generation mechanism.6 page

Effectiveness of GF-120 NF Naturalyte Fruit Fly Bait Spray against Different Ages of Melon Fly (Diptera: Tephritidae) Females When Applied to Border Crops of Various Widths

GF-120 NF Naturalyte Fruit Fly Bait was evaluated for its effectiveness to prevent melon fly, Bactrocera cucurbitae (Coquillett), females of various ages from ovipositing in cucumber patches with border crops of different widths. Cohorts of color-marked, protein-fed females, eclosed after 1, 2, or 4 weeks, were released from sites outside sorghum, (Sudax bicolor x S. bicolor var. sudanense) borders 1, 2, or 4 rows deep (30, 90, and 135 cm in width, respectively). Capture rates of female B. cucurbitae were higher for 2- and 4-week-old than for 1-week-old females. Borders sprayed with GF-120 NF Naturalyte Fruit Fly Bait were effective at preventing released sexually- mature 4-wk-old females from reaching the cucumber patches only when in association with the widest border (135 cm) treatment. Our findings suggest that for maximum effectiveness against host-seeking female B. cucurbitae, GF-120 NF Naturalyte Fruit Fly Bait should be applied to broader swaths of sorghum planted as a border crop

High Input Voltage Discharge Supply for High Power Hall Thrusters Using Silicon Carbide Devices

A power processing unit for a 15 kW Hall thruster is under development at NASA Glenn Research Center. The unit produces up to 400 VDC with two parallel 7.5 kW discharge modules that operate from a 300 VDC nominal input voltage. Silicon carbide MOSFETs and diodes were used in this design because they were the best choice to handle the high voltage stress while delivering high efficiency and low specific mass. Efficiencies in excess of 97 percent were demonstrated during integration testing with the NASA-300M 20 kW Hall thruster. Electromagnet, cathode keeper, and heater supplies were also developed and will be integrated with the discharge supply into a vacuum-rated brassboard power processing unit with full flight functionality. This design could be evolved into a flight unit for future missions that requires high power electric propulsion

NEXT Single String Integration Test Results

As a critical part of NASA's Evolutionary Xenon Thruster (NEXT) test validation process, a single string integration test was performed on the NEXT ion propulsion system. The objectives of this test were to verify that an integrated system of major NEXT ion propulsion system elements meets project requirements, to demonstrate that the integrated system is functional across the entire power processor and xenon propellant management system input ranges, and to demonstrate to potential users that the NEXT propulsion system is ready for transition to flight. Propulsion system elements included in this system integration test were an engineering model ion thruster, an engineering model propellant management system, an engineering model power processor unit, and a digital control interface unit simulator that acted as a test console. Project requirements that were verified during this system integration test included individual element requirements ; integrated system requirements, and fault handling. This paper will present the results of these tests, which include: integrated ion propulsion system demonstrations of performance, functionality and fault handling; a thruster re-performance acceptance test to establish baseline performance: a risk-reduction PMS-thruster integration test: and propellant management system calibration checks

High Power Silicon Carbide (SiC) Power Processing Unit Development

NASA GRC successfully designed, built and tested a technology-push power processing unit for electric propulsion applications that utilizes high voltage silicon carbide (SiC) technology. The development specifically addresses the need for high power electronics to enable electric propulsion systems in the 100s of kilowatts. This unit demonstrated how high voltage combined with superior semiconductor components resulted in exceptional converter performance

Development of High-Power Hall Thruster Power Processing Units at NASA GRC

NASA GRC successfully designed, built and tested four different power processor concepts for high power Hall thrusters. Each design satisfies unique goals including the evaluation of a novel silicon carbide semiconductor technology, validation of innovative circuits to overcome the problems with high input voltage converter design, development of a direct-drive unit to demonstrate potential benefits, or simply identification of lessonslearned from the development of a PPU using a conventional design approach. Any of these designs could be developed further to satisfy NASA's needs for high power electric propulsion in the near future