Tracking and Data Relay Satellite System (TDRSS)

The DSN (Deep Space Network) mission support requirements for the Tracking and Data Relay Satellite System (TDRSS) are summarized. The TDRSS consists of four identical satellites in geosynchronous orbits (35,800 km) and a dedicated ground station. The payload of each satellite is a telecommunications service system that relays communication signals between low earth-orbiting user spacecraft and the TDRSS ground terminal. Mission objectives are outlined and the DSN support requirements are defined through the presentation of tables and narratives describing the spacecraft flight profile; DSN support coverage; frequency assignments; support parameters for telemetry, command and support systems; and tracking support responsibility

Inhibitors of \u3cem\u3eN\u3csup\u3eα\u3c/sup\u3e\u3c/em\u3e-acetyl-l-ornithine Deacetylase: Synthesis, Characterization and Analysis of their Inhibitory Potency

A series of N α-acyl (alkyl)- and N α-alkoxycarbonyl-derivatives of l- and d-ornithine were prepared, characterized, and analyzed for their potency toward the bacterial enzyme N α-acetyl-l-ornithine deacetylase (ArgE). ArgE catalyzes the conversion of N α-acetyl-l-ornithine to l-ornithine in the fifth step of the biosynthetic pathway for arginine, a necessary step for bacterial growth. Most of the compounds tested provided IC50 values in the μM range toward ArgE, indicating that they are moderately strong inhibitors. N α-chloroacetyl-l-ornithine (1g) was the best inhibitor tested toward ArgE providing an IC50 value of 85 μM while N α-trifluoroacetyl-l-ornithine (1f), N α-ethoxycarbonyl-l-ornithine (2b), and N α-acetyl-d-ornithine (1a) weakly inhibited ArgE activity providing IC50 values between 200 and 410 μM. Weak inhibitory potency toward Bacillus subtilis-168 for N α-acetyl-d-ornithine (1a) and N α-fluoro- (1f), N α-chloro- (1g), N α-dichloro- (1h), and N α-trichloroacetyl-ornithine (1i) was also observed. These data correlate well with the IC50 values determined for ArgE, suggesting that these compounds might be capable of getting across the cell membrane and that ArgE is likely the bacterial enzymatic target

Die Amplituden von PP- und SS-Wellen in der Nahe von 40° und die Struktur des ausseren Erdmantels

Die anomale Zunahme von Amplituden der P- und S-Wellen inden Epizentralentfernungen um 20° wurde von melireren Autoren beobachtet(1- 3). Diese Erscheinung, die hòhstwalirscheinlich mit denbeobaehteten Krummungsànderungen der Laufzeitkurven der P- undS-Wellen in demselben Distanzbereicli zusammenliàngt, trat sehr deutlichbei der empirischen Ableitung der Eichfunktionen E (zi) fùr dieBestimmung von Magnituden aus Raumwellen auf Grund Prager Beobachtungenhervor (4). Eine ahnliche Zunahme von Amplituden derPP- und SS-Wellen wurde bei dieser Gelegenheit in der Nahe von 40°beobachtet. Von verschiedenen Autoren (5>6) wurde die Notwendigkeitder systematischen Untersuchung von Amplituden der P- und S-Wellenin einem gròsseren Distanzbereich fùr die Erklàrung der 20° Diskontinuitàtmehrmals betont. Deshalb wurden in Prag die Untersuchungenin dieser Eiclitung auf Grund eines noch zahlreicheren Materials vorgenommen

Tunable far infrared studies of molecular parameters in support of stratospheric measurements

Lab studies were made in support of far infrared spectroscopy of the stratosphere using the Tunable Far InfraRed (TuFIR) method of ultrahigh resolution spectroscopy and, more recently, spectroscopic and retrieval calculations performed in support of satellite-based atmospheric measurement programs: the Global Ozone Monitoring Experiment (GOME), and the SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY (SCIAMACHY)

Quinhydrone Chemical Passivation of a Silicon Surface for Minority Carrier Bulk-Lifetime Measurements

For the measurement of the minority carrier bulk-lifetime the characterization method MW-PCD is used, where the result of measurement is the effective carrier lifetime, which is very dependent on the surface recombination velocity and therefore on the quality of a silicon surface passivation. This work deals with an examination of a different solution types for the chemical passivation of a silicon surface. Various solutions are tested on silicon wafers for their consequent comparison. The main purpose is to find optimal solution, which suits the requirements of a time stability and start-up velocity of passivation, reproducibility of the measurements and a possibility of a perfect cleaning of a passivating solution remains from a silicon surface, so that the parameters of a measured silicon wafer will not worsen and there will not be any contamination of the other wafers series in the production after a repetitive return of the measured wafer into the production process. The cleaning process itself is also a subject of a development

The Big Sky Model: A Regional Collaboration for Participatory Research on Environmental Health in the Rural West

As an innovative community-based framework for science learning, the Big Sky Model is guiding high school and tribal college students from rural areas of Montana and Idaho in their understanding of chemical, physical, and environmental health concepts in the context of their own homes, schools, and communities. Students participate in classroom lessons and continue with systematic inquiry through actual field research to investigate a pressing, real-world issue: understanding the complex links between poor air quality and respiratory health outcomes. This article provides background information, outlines the procedure for implementing the model, and discusses its effectiveness as demonstrated through various evaluation tools

Las mezclas de gramíneas y leguminosas muestran el potencial de aumentar la producción de biomasa aérea y subterránea en los barbechos andinos basados en el forraje

Descargue el texto completo en el portal de la revista Agronomy: https://doi.org/10.3390/agronomy12010142Los suelos altoandinos están amenazados por la intensificación de los sistemas de cultivo. Los barbechos mejorados basados en el forraje ofrecen una gran promesa para abordar este problema, pero es necesario investigar para entender mejor el potencial de las mezclas de especies frente a los monocultivos para apoyar múltiples objetivos de los agricultores, especialmente la producción de forraje y la conservación del suelo. Hemos utilizado un estudio en maceta para cuantificar la producción de biomasa aérea y subterránea, así como la absorción total de N de las mezclas de gramíneas y leguminosas entre cinco gramíneas: (1) avena (Avena sativa), (2) ryegrass (Lolium multiflorum), (3) festulolium (Lolium × Festuca genera), (4) bromo (Bromus catharticus), y (5) hierba de la huerta (Dactylis glomerata), y cuatro leguminosas: (1) veza (Vicia dasycarpa), (2) trébol rojo (Trifolium pratense), (3) medicago negro (Medicago lupulina), y (4) alfalfa (Medicago sativa) en relación al rendimiento de cada especie en monocultivo dentro de dos suelos de los Andes centrales peruanos. Los bicultivos de gramíneas y leguminosas demostraron un rendimiento superior, produciendo un 65% y un 28% más de biomasa seca total y de absorción total de N en promedio que los monocultivos. La biomasa aérea de los bicultivos estuvo significativamente influenciada por la especie de leguminosa presente, mientras que la biomasa subterránea estuvo más afectada por la especie de hierba en la mezcla. Al evaluar el crecimiento de cada especie por separado, nuestros resultados indican que el exceso de rendimiento fue impulsado más por el mayor crecimiento de las gramíneas en relación con las leguminosas. Nuestros resultados indican que la combinación de grupos funcionales clave (p. ej., gramíneas y leguminosas, anuales y perennes) es muy prometedora para el desarrollo de barbechos mejorados que apoyen la salud del suelo y la productividad en los agroecosistemas andinos.Soils of the Andean highlands are under threat from cropping system intensification. Improved forage-based fallows offer great promise to address this issue, but research is needed to better understand the potential of species mixtures vs. monocultures to support multiple farmer objectives, especially forage production and soil conservation. We used a pot study to quantify above- and belowground biomass production as well as the total N uptake of grass–legume pairs between five grasses: (1) oat (Avena sativa), (2) ryegrass (Lolium multiflorum), (3) festulolium (Lolium × Festuca genera), (4) brome grass (Bromus catharticus), and (5) orchard grass (Dactylis glomerata), and four legumes: (1) vetch (Vicia dasycarpa), (2) red clover (Trifolium pratense), (3) black medic (Medicago lupulina), and (4) alfalfa (Medicago sativa) relative to the performance of each species in monoculture within two soils from the central Peruvian Andes. Grass–legume bicultures demonstrated significant overyielding, producing 65% and 28% more total dry biomass and total N uptake on average than monocultures. Aboveground biomass of bicultures was significantly influenced by the species of legume present, while belowground biomass was more affected by the grass species in the mixture. When evaluating the growth of each species separately, our findings indicate that overyielding was driven more by the enhanced growth of grasses relative to legumes. Our findings indicate that combining key functional groups (e.g., grass and legume, annual and perennial) offers great promise for developing improved fallows for supporting soil health and productivity in Andean agroecosystems