Slew maneuvers on the SCOLE Laboratory Facility

The Spacecraft Control Laboratory Experiment (SCOLE) was conceived to provide a physical test bed for the investigation of control techniques for large flexible spacecraft. The control problems studied are slewing maneuvers and pointing operations. The slew is defined as a minimum time maneuver to bring the antenna line-of-sight (LOS) pointing to within an error limit of the pointing target. The second objective is to rotate about the LOS within the 0.02 degree error limit. The SCOLE problem is defined as two design challenges: control laws for a mathematical model of a large antenna attached to the Space Shuttle by a long flexible mast; and a control scheme on a laboratory representation of the structure modelled on the control laws. Control sensors and actuators are typical of those which the control designer would have to deal with on an actual spacecraft. Computational facilities consist of microcomputer based central processing units with appropriate analog interfaces for implementation of the primary control system, and the attitude estimation algorithm. Preliminary results of some slewing control experiments are given

The Great Albatross Philippine Expedition and Its Fishes

The Philippine Expedition of 1907-10 was the longest and most extensive assignment of the Albatross's 39-year career. It came about because the United States had acquired the Philippines following the Spanish-American War of 1898 and the bloody Philippine Insurection of 1899-1902. The purpose of the expedition was to surbey and assess the aquatic resources of the Philippine Islands. Dr. Hugh M. Smith, the Deputy Commissioner of the U.S. Bureau of Fisheries, was the Director of the Expedition. Other scientific participants were Frederick M. Chamberlain, Lewis Radcliffe, Paul Bartsch, Harry C. Fasset, Clarence Wells, Albert Burrows, Alvin Seale, and Roy Chapman Andrews. The expedition consisted of a series of cruises, each beginning and ending in Manila and exploring a different part of the island group. In addition to the Philippines proper, the ship also explored parts of the Dutch East Indies and areas around Hong Kong and Taiwan. The expedition returned great quantities of fish and invertebrate speciments as well as hydrographic and fisheries data; most of the material was eventually deposited in the Smithsonian Institution's National Museum of Natural History. The fisehs were formally accessioned into the museum in 1922 and fell under the car of Barton A. Bean, Assistant Curator of Fishes, who then recruited Henry W. Fowler to work up the material. Fowler completed his studies of the entire collection, but only part of it was ever published, due in part to the economic constraints caused by the Depression. The material from the Philippine Expedition constituted the largest single accession of fishes ever received by the museum. These speciments are in good condition today and are still being used in scientific research

The "supply-of-storage" for natural gas in California

Do natural gas storage decisions in California respond to futures price spreads? Daily data about flows into and out of storage facilities in California over 2001-2005 and daily price spreads are used to investigate whether the net injection profile is consistent with the "supply-of-storage" curve deduced by Working for wheat. Storage decisions in California do seem to be influenced by intertemporal signals on NYMEX, but the magnitude of the effect is small. Strong seasonal and weekly cycles determine the net injection profile to a considerable extent. Regulatory requirements and operational constraints also limit the size of the response to intertemporal arbitrage opportunities. Results are surprisingly sensitive to the level of aggregation considered.Resource /Energy Economics and Policy,

Non-Institutional Market Making Behavior: The Dalian Futures Exchange

This paper contains three useful contributions: (1) it collects a new data-set of electronic transaction data on soybean futures from the Dalian Futures Exchange in China that records, not only the usual elements of each transaction (such as price and size) but also identifies broker and customer identities, variables not usually obtainable; (2) it presents new econometric methods for the analysis of dynamic multivariate count data based on the autoregressive conditional intensity model of Jordà and Marcellino (2000); and (3) together, the new data and econometric methods allow us to investigate, in a manner not available before, the determinants and effects of non-institutional market making (or scalping).market making, autoregressive conditional intensity, high-frequency data

Description of the Spacecraft Control Laboratory Experiment (SCOLE) facility

A laboratory facility for the study of control laws for large flexible spacecraft is described. The facility fulfills the requirements of the Spacecraft Control Laboratory Experiment (SCOLE) design challenge for a laboratory experiment, which will allow slew maneuvers and pointing operations. The structural apparatus is described in detail sufficient for modelling purposes. The sensor and actuator types and characteristics are described so that identification and control algorithms may be designed. The control implementation computer and real-time subroutines are also described

MARKET-MAKING BEHAVIOR IN FUTURES MARKETS

This paper examines voluntary market-making behavior, namely scalping, in futures markets. Specifically, this paper studies what factors determine scalpers' entry and exit, and how scalping affects market liquidity and price volatility. The data used for the analysis are time-stamped electronic transaction data marked with traders' identities from the Dalian Futures Exchanges in China. The contributions of this paper are: (1) to give detailed analysis of scalping behavior and its impact on market liquidity; (2) to develop new econometric tools for analyzing time-series count data; (3) to propose a new measure of liquidity.Liquidity, Market-Making, Futures Markets, Scalpers, Autoregressive Conditional Intensity (ACI), Volatility, Marketing,

Development of a phage display library for discovery of antigenic Brucella peptides

Current serological diagnostics of the zoonotic disease brucellosis, caused by the intracellular, facultative bacterial pathogen Brucella, is primarily limited to humoral antibodies against the O-side chain of the lipopolysaccharide. This limitation can result in false positives due to cross reactivity with other gram negative bacteria. Previous attempts to identify other molecular markers for diagnostic purposed haven’t resulted in sensitive and specific antigens. In the current study, we employed a new method for discovering novel Brucella proteins that induce humoral responses in cattle. We developed a phage display library that expresses 56 amino acid long Brucella peptides. Screening the library with sera from B. abortus RB51 infected cattle demonstrated that it identified antigenic peptides of Brucella. Fifty peptides demonstrated greater humoral responses at 30 days after RB51 infection as compared to sera obtained prior to vaccination. Peptides identified in the study could be beneficial as potential targets for novel Brucella diagnostics