7,305 research outputs found
Modifications to CTVS TV cameras for space shuttle compatibility and evaluation
Five all solid state cockpit television system (CTVS) cameras, built to USAF requirements for high performance type F-16 aircraft, were modified and tested for possible use in the closed circuit television system on the space shuttle orbiter. The 400 HZ power supply in the electronics unit assembly was replaced with two DC/DC converters to enable operation from 28VDC spacecraft-type power sources. Nonessential circuit functions were deleted to minimize input power requirements. The normal 31 mm focal length lense assemblies were replaced with wider field-of-view 19 mm focal length lenses. Base plates for and housings were redesigned to facilitate mounting and heat-sinking of the camera in the space environment and short length (14") adapter cables were designed, fabricated, and tested to meet requirements for cameras configured to mount on the astronauts helmet/visor assembly. Technical requirements, design implementation, environmental tests, Modifications prodedures, and reliability/quality efforts are discussed. Schematics are included
A MODEL OF BYCATCH INVOLVING A PASSIVE USE STOCK
We develop a simple extension of the theory of multispecies fisheries management to analyze a problem where one fish or animal stock has no commercial market but instead is valued passively. We interpret a typical by bycatch problem as a standard multispecies fisheries management problem, and we develop a multispecies model incorporating both monetary damages associated with bycatch and variable biological relationships. We examine the behavior of the model with a numerical example focusing on the case of the bycatch of spotted and other dolphins in the eastern tropical Pacific (ETP) yellowfin tuna fishery.Resource /Energy Economics and Policy,
DIVERSIFYING AGRICULTURAL SYSTEMS: AN EXTERNAL ANALYSIS OF STATE VALUE-ADDED PROGRAMS
An increasing number of farmers in the United States are finding more opportunity to participate in value-added activities beyond their commodity production. Issues' such as low farm income, increasing marketing margins, and a desire to enhance demand for local commodities-generate more interest in identifying suitable value-added activities. Many states are providing programs to help promote and support farmers interested in leading the development of new food products. This paper examines the objectives and development strategies of several value-added state programs. Special attention is paid to the extent to which the programs create opportunities for farmers in different income groups. Programs profiled in this research include Iowa's Rural Economic Value-Added Mentoring Program (REVAMP), North Dakota's Agricultural Utilization Research Institute (AURI), Minnesota's Agricultural Products Utilization Commission (APUC), and other centers and programs in Colorado, Tennessee, Mississippi, and Oklahoma. A survey is conducted of the center directors to provide a profile of each program's scope and state's objectives, development strategy, and performance measures. This paper assesses the effectiveness of variously structured value-added programs as stated by the survey; it also summarizes recommended strategies for improvement. Cost considerations and long-term justification of these value-added centers is also considered. Institutional design, recommendations, central policy issues, and program performance measures are discussed. States considering the implementation or expansion of such programs will want to evaluate their design based on these findings.Agricultural and Food Policy,
Solid state, CCD-buried channel, television camera study and design
An investigation of an all solid state television camera design, which uses a buried channel charge-coupled device (CCD) as the image sensor, was undertaken. A 380 x 488 element CCD array was utilized to ensure compatibility with 525 line transmission and display monitor equipment. Specific camera design approaches selected for study and analysis included (a) optional clocking modes for either fast (1/60 second) or normal (1/30 second) frame readout, (b) techniques for the elimination or suppression of CCD blemish effects, and (c) automatic light control and video gain control techniques to eliminate or minimize sensor overload due to bright objects in the scene. Preferred approaches were determined and integrated into a design which addresses the program requirements for a deliverable solid state TV camera
Security Policy Specification Using a Graphical Approach
A security policy states the acceptable actions of an information system, as
the actions bear on security. There is a pressing need for organizations to
declare their security policies, even informal statements would be better than
the current practice. But, formal policy statements are preferable to support
(1) reasoning about policies, e.g., for consistency and completeness, (2)
automated enforcement of the policy, e.g., using wrappers around legacy systems
or after the fact with an intrusion detection system, and (3) other formal
manipulation of policies, e.g., the composition of policies. We present LaSCO,
the Language for Security Constraints on Objects, in which a policy consists of
two parts: the domain (assumptions about the system) and the requirement (what
is allowed assuming the domain is satisfied). Thus policies defined in LaSCO
have the appearance of conditional access control statements. LaSCO policies
are specified as expressions in logic and as directed graphs, giving a visual
view of policy. LaSCO has a simple semantics in first order logic (which we
provide), thus permitting policies we write, even for complex policies, to be
very perspicuous. LaSCO has syntax to express many of the situations we have
found to be useful on policies or, more interesting, the composition of
policies. LaSCO has an object-oriented structure, permitting it to be useful to
describe policies on the objects and methods of an application written in an
object-oriented language, in addition to the traditional policies on operating
system objects. A LaSCO specification can be automatically translated into
executable code that checks an invocation of a program with respect to a
policy. The implementation of LaSCO is in Java, and generates wrappers to check
Java programs with respect to a policy.Comment: 28 pages, 22 figures, in color (but color is not essential for
viewing); UC Davis CS department technical report (July 22, 1998
The world wide spread of space technology
Space technological capabilities and developments in US, USSR, Western Europe, Japan, China, and developing nation
An Analysis of the Relationship between Fish Harvesting and Processing Sectors in New England
Using annual data from 1981 to 2002, the relationship between harvesting and processing of fish and the effects of imports on processing in New England were analyzed. Additionally, cause and effect relationships between harvesting and processing and between processing and imports were examined using Granger causality tests. Output from the fish processing sector is jointly driven by local fish landings and fish imports and unidirectional causalities exist from local landings to processing and from processing to imports. Generally, processors optimize business operations over multiple species and multiple supply sources. Rebuilding the groundfish stock would not lead to a dramatic and immediate increase in the processing industry. Instead, the actual growth in the processing sector would be relatively smaller than that in the harvesting sector.Fish processing, fish harvesting, fish imports, causality., Q2, Q22, L66, Resource /Energy Economics and Policy,
The mycoherbicide Atlernaria cassiae infects and alters phenolic metabolism of Cassia alata seedlings
Le mycoherbicide Alternaria cassiae, un agent pathogène du Cassia obtusifolia a infecté le Cassia alata, une espèce de Cassia jamais testée auparavant. Quand des plantules de C. alata âgées de 2 semaines et cultivées en cabinets de croissance ont été inoculées avec 105 spores mL-1 suivi d'une période d'humectation de 12 h, l'infection était apparente 16-20 h après le traitement. La sévérité de l'infection était proportionnelle à la concentration de spores, 106 spores mL-1 entraînant une mortalité complète 4-5 jours après le traitement. L'âge des plantes influençait la gravité de la maladie et l'efficacité du myco- herbicide. À 106 spores mL-1, 95 % des plantes âgées de 1-3 semaines étaient mortes, et les survivantes montraient des dommages graves; les plantes âgées de 3-4 semaines présentaient des lésions multiples, une réduction de croissance et une chute des feuilles. Finalement les plantes âgées de 5-7 semaines étaient infectées et présentaient plusieurs lésions mais elles ont repris le dessus sur la maladie. La quantité de phénylalanine-ammonia-lyase extractible des plantules de C. alata traitées était trois fois plus élevée que chez les plantules non traitées 17-96 h après l'application des spores. Les niveaux d'hydroxyphénols solubles étaient aussi plus élevés dans les plantules traitées à l'A cassiae, mais seulement 48-96 h après le traitement. Les résultats indiquent que la gamme d'hôtes de cet agent pathogène est très large, et suggèrent que le métabolisme des composés phénoliques est accéléré en réponse à l'invasion par l'agent pathogène.The mycoherbicide Alternaria cassiae, a pathogen of the weed sicklepod (Cassia obtusifolia), was found to infect a previously untested Cassia species, Cassia alata (ringworm bush or seven golden candlesticks). When 2-wk-old, growth chamber-grown C. alata seedlings were inoculated with 105 spores mL-1 followed by a 12-h dew period, infection was apparent 16-20 h after treatment. Infection severity was proportional to spore concentration, and 106 spores mL-1 caused complete mortality 4-5 d after treatment. Plant age was also a factor in disease severity and mycoherbicidal efficacy. At 106 spores mL-1, 95% of 1- to 3-wk-old seedlings were killed (with severe damage to others); 3- to 4-wk-old plants had multiple lesions, growth reduction, and some leaf abscission; and 5- to 7-wk-old plants were infected with many lesions, but they outgrew these effects. Extractable phenylalanine ammonialyase in treated C. alata seedlings was increased three-fold above that of untreated seedlings 17-96 h after spore application. Soluble hydroxyphenolic levels were also increased in the A. cassiae-treated seedlings, but not until 48-96 h after treatment. Results indicate an expanded host range for this plant pathogen and suggest that phenolic metabolism is increased in défense of pathogen invasion
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