Magnetic attachment mechanism

A magnetic attachment mechanism adapted for interfacing with the manipulator arm of a remote manipulator system and comprising a pair of permanent magnets of rare earth material are arranged in a stator-rotor relationship. The rotor magnet is journalled for rotation about its longitudinal axis between pole plates of the stator magnet, each of which includes an adhering surface. In a first rotary position corresponding to the ON condition, each of the poles of the rotor magnet is closely adjacent to a stator magnet pole plate of like polarity whereby the respective magnet fields are additive for producing a strong magnetic field emanating from the adhering surfaces for attracting a ferrous magnetic plate, or the like, affixed to the payload. When the rotor magnet is rotated to a second position corresponding to the OFF condition, each of the poles of the rotor magnet is disposed closely adjacent to a pole plate of unlike polarity whereby the magnetic fields of the magnets are in cancelling relationship at the adhering surfaces, which permits the release of a payload. An actuator for selectively rotating the rotor magnet between the ON and OFF positions is provided for interfacing and connecting the magnetic attachment mechanism with a manipulator arm. For affecting an optimal rigidized attachment the payload is provided with guide means cooperable with guide means on the housing of the mechanism for directing adhering surfaces of the polar plates to the ferrous plate

Archetypal analysis of galaxy spectra

Archetypal analysis represents each individual member of a set of data vectors as a mixture (a constrained linear combination) of the pure types or archetypes of the data set. The archetypes are themselves required to be mixtures of the data vectors. Archetypal analysis may be particularly useful in analysing data sets comprising galaxy spectra, since each spectrum is, presumably, a superposition of the emission from the various stellar populations, nebular emissions and nuclear activity making up that galaxy, and each of these emission sources corresponds to a potential archetype of the entire data set. We demonstrate archetypal analysis using sets of composite synthetic galaxy spectra, showing that the method promises to be an effective and efficient way to classify spectra. We show that archetypal analysis is robust in the presence of various types of noise.Comment: 6 pages, 5 figures, 1 style-file. Accepted for publication by MNRA

Circular 78

Historically, sales of exotic meats have been limited only by supply. As supply has increased in recent years, national and international exotic game markets have grown rapidly. In the United States, growth has occurred primarily in the restaurant section, although over-the-counter sales have also increased. The Alaskan reindeer industry is exploring the potential of expanding its meat sales as well as antler sales. Meat production increased from 320,000 pounds in 1987 to 432,000 pounds in 1988. This production increase is reflected in a 27 percent increase in dollar value (Alaska Crop and Livestock Reporting Service, 1989). Under current management procedures, potential meat production has been estimated at 500,000 pounds (Pearson and Lewis, 1988). Any future market expansion is likely to occur in urban Alaska and in areas outside the state (Jones, 1988)

Adoption of Best Management Practices to Control Weed Resistance By Cotton, Corn, and Soybean Growers

This study examined adoption of ten best management practices (BMPs) to control weed resistance to herbicides. Using data from a survey of 1,205 U.S. cotton, corn, and soybean growers, count data models were estimated to explain the total number of practices frequently adopted. Ordered probit regressions were used to explain the frequency of individual BMP adoption. Growers practicing a greater number of BMPs frequently (a) had more education, but less farming experience; (b) grew cotton, (c) expected higher yields relative to the county average; and (d) farmed in counties with a lower coefficient of variation (CV) for yield of their primary crop. Yield expectations and variability were significant predictors of the frequency of adoption of individual BMPs. Most growers frequently adopted the same seven BMPs. Extension efforts may be more effective if they target a minority of growers and the three practices with low adoption rates. Counties with a high yield CV would be areas to look for low BMP adoption.weeds, herbicide, resistance management, corn, cotton, soybeans, adoption, Crop Production/Industries, Farm Management, Production Economics, Research and Development/Tech Change/Emerging Technologies, Q12, Q16,

Valuing the Roundup Ready® Soybean Weed Management Program

This study examines soybean grower adoption of the Roundup Ready® (RR) weed management program with and without a residual herbicide application, and grower concerns regarding weed resistance to herbicides using telephone survey data from of 357 growers in 2007. It also estimates the pecuniary and non-pecuniary benefits enjoyed by growers from their RR program. The results indicate that soybean growers planned to treat 29 percent of their RR acres with a residual herbicide in 2008. More than half (53%) of the growers survey were concerned about weed resistance. The estimated expected benefit of the RR program in 2008 was $10.17 per acre, which translates into about$727 million with 75.7 million acres of soybean in the U.S. in 2008. The estimated value per acre of the RR program with and without a residual was $8.78 and$12.83. The estimates also suggest that if growers were not using residual herbicides with the RR program, their benefits would be 28.4% lower. Alternatively, if all growers were required to use residual herbicides on their RR acres, the value of the RR program would be 46% lower. Simply increasing grower weed resistance concerns could increase residual herbicide use on RR acres by up to 7%. The same increase in residual herbicide use could be accomplished by decreasing the cost of residual herbicide applications on RR acres by $0.81 per acre.Roundup Ready, Soybean, Glyphosate, Weed Resistance, Benefits, Crop Production/Industries, Demand and Price Analysis, Farm Management, Research and Development/Tech Change/Emerging Technologies,

From one solution of a 3-satisfiability formula to a solution cluster: Frozen variables and entropy

A solution to a 3-satisfiability (3-SAT) formula can be expanded into a cluster, all other solutions of which are reachable from this one through a sequence of single-spin flips. Some variables in the solution cluster are frozen to the same spin values by one of two different mechanisms: frozen-core formation and long-range frustrations. While frozen cores are identified by a local whitening algorithm, long-range frustrations are very difficult to trace, and they make an entropic belief-propagation (BP) algorithm fail to converge. For BP to reach a fixed point the spin values of a tiny fraction of variables (chosen according to the whitening algorithm) are externally fixed during the iteration. From the calculated entropy values, we infer that, for a large random 3-SAT formula with constraint density close to the satisfiability threshold, the solutions obtained by the survey-propagation or the walksat algorithm belong neither to the most dominating clusters of the formula nor to the most abundant clusters. This work indicates that a single solution cluster of a random 3-SAT formula may have further community structures.Comment: 13 pages, 6 figures. Final version as published in PR

Magnetic attachment mechanism

A magnetic attachment mechanism adapted for interfacing with the manipulator arm (11) of a remote manipulator system and comprising a pair of permanent magnets (31,32) of rare earth material which are arranged in a stator-rotor relationship. The rotor magnet (32), is journalled for rotation about its longitudinal axis between pole plates (35,36) of the stator magnet (31), each of which includes an adhering surface (35a,36a). In a first rotary position corresponding to the ON condition, each of the poles of the rotor magnet (32) is closely adjacent a stator magnet pole plate of like polarity whereby the respective magnet fields are additive for producing a strong magnetic field emanating from the adhering surfaces (35a,36a) for attracting a ferrous magnetic plate 20, or the like, affixed to the payload (20 or 50). When the rotor magnet (32) is rotated to a second position corresponding to the OFF condition, each of the poles of the rotor magnet (31) is disposed closely adjacent a pole plate of unlike polarity whereby the magnetic fields of the magnets are in cancelling relationship at the adhering surfaces (35a,36a) which permits the release of a payload. An actuator (51 or 70) for selectively rotating the rotor magnet (32) between the ON and OFF positions is provided for interfacing and connecting the magnetic attachment mechanism with a manipulator arm. For effecting an optimal rigidized attachment the payload is provided with guides (91,92) cooperable with guides (96,16,17) on the housing of the mechanism for directing adhering surfaces (35a,36a) of the polar plates to the ferrous plate (20)

Momentum Analyticity and Finiteness of the 1-Loop Superstring Amplitude

The Type II Superstring amplitude to 1-loop order is given by an integral of $\vartheta$-functions over the moduli space of tori, which diverges for real momenta. We construct the analytic continuation which renders this amplitude well defined and finite, and we find the expected poles and cuts in the complex momentum plane.Comment: 10pp, /UCLA/93/TEP/