The AMSC mobile satellite system: Design summary and comparative analysis

Mobile satellite communications will be provided in the United States by the American Mobile Satellite Consortium (AMSC). Telesat Mobile, Inc. (TMI) and AMSC are jointly developing MSAT, the first regional Mobile Satellite Service (MSS) system. MSAT will provide diverse mobile communications services - including voice, data and position location - to mobiles on land, water, and in the air throughout North America. Described here are the institutional relationships between AMSC, TMI and other organizations participating in MSAT, including the Canadian Department of Communications and NASA. The regulatory status of MSAT in the United States and international allocations to MSS are reviewed. The baseline design is described

Archaeological Sites Along Cuthand Creek and the Sulphur River in the Mid–Sulphur River Basin, Red River County, Texas

The Cuthand Creek and Little Mustang Creek drainage basins in the mid–Sulphur River basin are in the Post Oak Savannah of East Texas. Prehistoric archaeological sites are abundant in both basins and along the Sulphur River, dating from as early as Paleoindian times to the Late Caddo periods. Nevertheless, this area remains poorly known and there have been few professional archaeological investigations conducted here. In this article, we present information on a range of prehistoric sites and associated artifact assemblages known along Cuthand Creek and the Sulphur River in the mid–Sulphur River Basin, in Red River County, Texas. The artifacts that are discussed herein are in the collections of the junior author

The Benefit Function Approach to Modeling Price-Dependent Demand Systems: An Application of Duality Theory

In this article we advocate more extensive use of the benefit function in specifying price-dependent or inverse demand models. In particular, we demonstrate how duality theory may be used to establish the inter-relationships between the Marshallian (or Hicksian) inverse demands and Luenberger's adjusted price functions, allowing estimable inverse demands to be derived directly from a benefit function. We also make use of a numerical inversion estimation method to rectify the "unobservability of utility problem" encountered in the empirical analysis of these inverse demands. To illustrate the usefulness of the proposed methods, we estimate two systems of inverse demands for Japanese quarterly fish consumption. Results generally indicate that the proposed methods are promising and operationally feasible so that we have opened up a wider range of empirical inverse demand specifications that can be subjected to tight theoretical restrictions.Benefit Functions; Duality Theory; Numerical Inversion Estimation Method

Quantifying the Differences in Binding Affinity of Reduced Glutathione for Glutathione S-Transferase at pH 6.5 and 8.5 Using Isothermal Titration Calorimetry

The binding affinity between an enzyme and its substrate is often dependent on the pH of the local environment. Knowing the pH at which reduced glutathione (GSH) binds with the highest affinity to the enzyme glutathione S-transferase (GST) is useful for determining the optimal pH for purification of GST-fusion proteins during GST-affinity chromatography. In this study, GST of the species Schistosoma japonicum was purified, quantified, and utilized to study its binding interaction with GSH at pH 6.5 and 8.5 via isothermal titration calorimetry (ITC). After protein expression, extraction, and purification, the GST concentration was quantified using QubitTM fluorometry. Thermodynamic properties and a dissociation constant (KD) for each experiment were obtained utilizing the MicroCal PEAQ-ITC Analysis Software for the binding of GSH to GST at pH 6.5 and 8.5. Statistical analysis of the technical replicate data was performed to obtain an average and standard deviation of the KD at each pH point. The results indicate a statistically significant difference (

Facts and Fantasies about Commodity Futures

We construct an equally-weighted index of commodity futures monthly returns over the period between July of 1959 and March of 2004 in order to study simple properties of commodity futures as an asset class. Fully-collateralized commodity futures have historically offered the same return and Sharpe ratio as equities. While the risk premium on commodity futures is essentially the same as equities, commodity futures returns are negatively correlated with equity returns and bond returns. The negative correlation between commodity futures and the other asset classes is due, in significant part, to different behavior over the business cycle. In addition, commodity futures are positively correlated with inflation, unexpected inflation, and changes in expected inflation.

STRUCTURAL DEVELOPMENTS IN THE CANADIAN GRAINS AND OILSEEDS SECTOR

Industrial Organization,

Quantitative profiling of BATF family proteins/JUNB/IRF hetero-trimers using Spec-seq

Additional file 6. Half site analysis for BATFx-JUNB-IRFx. (A) Single variants from half sites of these oligos in the library were used to generate energy logos. Bolded positions represent the half sites generated in B. (B) Energy logos from Spec-seq results of BATFx-JUNB-IRFx. The Y-axis is negative energy so the preferred sequence is on the top

TAVERNS and the space station software support environment

The Space Station Information System (SSIS) provides the data processing capability for the Space Station Program (SSP). The Software Support Environment (SSE) System for the SSP is the collection of software, procedures, standards, hardware specification, documentation, policy, and training materials. The Ada programming language was baselined by the Space Station Program Office as the language for development and maintenance of all space station software including the software of the SSE itself. The Test And Validation Environment for Remote Networked Systems (TAVERNS) is a distributed philosophy for development and validation of Ada applications software for the space station and as such is closely related to the SSE. An overview of the system is provided

Three legged walking mobile platform: Kinematic and dynamic analysis and simulation

The three legged walker is proposed as a mobile work platform for numerous tasks associated with lunar base site preparation and construction. It is seen as one of several forms of surface transportation, each of which will be best suited for its respective tasks. Utilizing the principle of dynamic stability and taking advantage of the Moon's gravity, it appears to be capable of walking in any radial direction and rotating about a point. Typical curved path walking could involve some combination of the radial and rotational movements. Comprised mainly of a body, six actuators, and six moving parts, it is mechanically quite simple. Each leg connects to the body at a hip joint and has a femur, a knee joint, and a tibia that terminates at a foot. Also capable of enabling or enhancing the dexterity of a series of implements, the walker concept provides a mechanically simple and weight efficient means of drilling, digging, mining, and transporting cargo, and performing other like tasks. A proof of principle machine demonstrated the feasibility of the walking concept