Polarization effects in millimeter wave propagation through rain: A review of present theory and a discussion of current experiments

An attempt was made to calculate the depolarization effects of rain on linearly or elliptically polarized millimeter waves. Results are given in graphs and tables

The influence of polarization on millimeter wave propagation through rain

The measurement and analysis of the depolarization and attenuation that occur when millimeter wave radio signals propagate through rain are described. Progress was made in three major areas: the processing of recorded 1972 data, acquisition and processing of a large amount of 1973 data, and the development of a new theoretical model to predict rain cross polarization and attenuation. Each of these topics is described in detail along with radio frequency system design for cross polarization measurements

A 20 Ghz Depolarization Experiment Using the ATS-6 Satellite

A depolarization experiment using the 20 GHz downlink from the ATS-6 satellite was described. The following subjects were covered: (1) an operational summary of the experiment, (2) a description of the equipment used with emphasis on improvements made to the signal processing receiver used with the ATS-5 satellite, (3) data on depolarization and attenuation in one snow storm and two rain storms at 45 deg elevation, (4) data on low angle propagation, (5) conclusions about depolarization on satellite paths, and (6) recommendations for the depolarization portion of the CTS experiment

The Cape San Blas Ecological Study

Eglin AFB on Cape San Blas consists of approximately 250 acres located about 180 miles east of the main Eglin reservation. This area lies on the S1. Joseph peninsula, part of a dynamic barrier island chain that extends across the northern Gulf of Mexico. Due to the natural forces that formed Cape San Blas and those that maintain this area, St. Joseph Peninsula has experienced severe land form change over time (see GIS land form change maps). These changes allow for fluctuations in habitat types along Cape San Blas (see GIS land cover change maps)that influence the floral and faunal species using this area. The dynamic environment along Cape San Blasincludes flatwoods, interdunal swale, rosemary scrub, and beachfront. These habitats support a wide array of species, including several threatened and endangered species such as the loggerhead sea turtle (Caretta caretta), PipingPlover (Charadnus melodus), Least Tern (Sterna antillarum), and Bald Eagle (Haliaeetus leucocephalus). Proper management of these species and their habitats require knowledge of their abundance and distribution, and the effects disturbances have on their survival. In addition to threatened and endangered flora and fauna, Cape San Blas also supports tourists and recreationists. Although Gulf County is sparsely populated, with approximately 13,000 inhabitants throughout 578 square miles, summer tourism and heavy recreational use of beaches for fishing, crabbing, and shelling place continued and increasing pressure on the natural resources of these areas (Rupert 1991). Gulf County is also one of the few remaining counties in Florida that permits vehicular traffic on its beaches, including Cape San Blas. In addition to recreational use of these habitats;EAFB also uses the area for military missions. Air Force property on Cape San Blas is primarily used for radar tracking of flying missions over the Gulf of Mexico, although in recent years it has been used for missile launchings and other various military activities. To allow continued military and public use of Air Force property while also protecting the unique flora and fauna of the area,EAFB proposed a characterization of the resources found along Cape San Blas. A complete inventory of the physical features of the area included investigating topography, soil chemistry, hydrology, archeology, and the dynamics of land mass and land cover change over time. Various thematic layers within a geographic information system (GIS) were used to spatially portray georeferenced data. Large scale changes over time were assessed using stereo aerial photography. Vegetation transects, soil samples, elevation transects, an archeological survey, freshwater wells, and a tidal monitor were used to investigate the remaining features. (247 page document

A depolarization and attenuation experiment using the CTS satellite. Volume 1: Experiment description

An experiment for measuring precipitation attenuation and depolarization on the Communications Technology Satellite (CTS) 11.7 GHz downlink is described. Attenuation and depolarization of the signal received from the spacecraft is monitored on a 24 hour basis. Data is correlated with ground weather conditions. Theoretical models for millimeter wave propagation through rain are refined for maximum agreement with observed data. Techniques are developed for predicting and mimimizing the effects of rain scatter and depolarization on future satellite communication systems

A depolarization and attenuation experiment using the COMSTAR and CTS satellites

Monthly statistical data are presented on ground rainfall rate and attenuation of satellite downlinks at 11.7 GHz, 19.04 GHz, and 28.56 GHz and on cross-polarization isolation at 11.7 GHz. Regression equations for relating isolation to attenuation, attenuation to rain rate, and attenuation at one frequency to attenuation at another frequency are also included. Longer-term statistics are also presented and discussed

Genomic islands of divergence in the Yellow Tang and the Brushtail Tang Surgeonfishes.

The current ease of obtaining thousands of molecular markers challenges the notion that full phylogenetic concordance, as proposed by phylogenetic species concepts, is a requirement for defining species delimitations. Indeed, the presence of genomic islands of divergence, which may be the cause, or in some cases the consequence, of speciation, precludes concordance. Here, we explore this issue using thousands of RAD markers on two sister species of surgeonfishes (Teleostei: Acanthuridae), Zebrasoma flavescens and Z. scopas, and several populations within each species. Species are readily distinguished based on their colors (solid yellow and solid brown, respectively), yet populations and species are neither distinguishable using mitochondrial markers (cytochrome c oxidase 1), nor using 5193 SNPs (pairwise Φst = 0.034). In contrast, when using outlier loci, some of them presumably under selection, species delimitations, and strong population structure follow recognized taxonomic positions (pairwise Φst = 0.326). Species and population delimitation differences based on neutral and selected markers are likely due to local adaptation, thus being consistent with the idea that these genomic islands of divergence arose as a consequence of isolation. These findings, which are not unique, raise the question of a potentially important pathway of divergence based on local adaptation that is only evident when looking at thousands of loci

Insect-mediated cross-pollination in soybean [Glycine max (L.) Merrill] : I. Agronomic performance

In soybean, manual cross-pollination to produce large quantities of F1 hybrid seed for yield trials is difficult and time-consuming. Conversely, insect-mediated cross-pollination has been shown to produce large quantities of hybrid seed in soybean and could facilitate the identification of heterotic patterns. The objective of our study was: (1) evaluate F1hybrid soybean plants from single crosses for yield and agronomic traits over several environments and (2) compare hybrid performance of the single crosses to lines developed from three-way crosses and backcrosses. In 2003, F1 seed of single-crosses and their parent lines were evaluated in replicated experiments at three locations. Also in 2003, three-way crosses, and BC1F1 seed were produced. In 2004, three-way crosses, BC1F1 crosses, and their parent lines were evaluated at one location. High-parent heterosis (HPH) in single-crosses for grain yield ranged from −41.11% to +11.19%; for protein content from −4.34% to +3.53%, and for oil content from −13.22% to −0.84%. In three-way crosses, HPH for yield ranged from −25.21% to −4.50%, for protein from −2.72% to +1.92%, and for oil from −5.87% to −1.20%. For BC1F1 crosses, HPH for yield ranged from −15.65% to +41.97%, for protein from −2.57% to +1.69%, and for oil from −2.47% to +2.22%. Although positive heterosis levels were observed across all populations tested to determine the economic feasibility it is imperative that more tests of more cross-combinations be evaluated in replicated environments. Extensive research in different environments must be conducted to determine what parental combinations will produce the highest heterosis levels, and to develop criteria for selecting the parents with the best combining ability. This will be important to maximize agronomic performance that can economically justify the use of hybrids in soybean production