8,079 research outputs found
ECONOMIC IMPACT OF INTRODUCING ROTATIONS ON LONG ISLAND POTATO FARMS
Potatoes have been grown continuously on many Long Island (New York) fields. Environmental concerns have raised questions about the continued usage of this practice. A farm-level linear programming model was used to investigate the economic impacts of crop rotations which result in reduced potato acreage. Crop rotations (an Integrated Pest Management tactic) reduced total pesticide use, but also reduced returns above variable costs as successively stringent rotation requirements were forced into the solution. The crop rotations which caused the least effect on income were identified.Resource /Energy Economics and Policy,
Observation of the angular momentum flux carried by the solar wind
Angular momentum flux carried by solar wind calculated from Mariner 5 dat
Airborne mapping of complex obstacles using 2D Splinegon
This paper describes a recently proposed algorithm in mapping the unknown
obstacle in a stationary environment where the obstacles are represented as
curved in nature. The focus is to achieve a guaranteed performance of sensor
based navigation and mapping. The guaranteed performance is quantified by
explicit bounds of the position estimate of an autonomous aerial vehicle using
an extended Kalman filter and to track the obstacle so as to extract the map of
the obstacle. This Dubins path planning algorithm is used to provide a flyable
and safe path to the vehicle to fly from one location to another. This
description takes into account the fact that the vehicle is made to fly around
the obstacle and hence will map the shape of the obstacle using the 2D-Splinegon
technique. This splinegon technique, the most efficient and a robust way to
estimate the boundary of a curved nature obstacles, can provide mathematically
provable performance guarantees that are achievable in practice
Strain actuated aeroelastic control
Viewgraphs on strain actuated aeroelastic control are presented. Topics covered include: structural and aerodynamic modeling; control law design methodology; system block diagram; adaptive wing test article; bench-top experiments; bench-top disturbance rejection: open and closed loop response; bench-top disturbance rejection: state cost versus control cost; wind tunnel experiments; wind tunnel gust alleviation: open and closed loop response at 60 mph; wind tunnel gust alleviation: state cost versus control cost at 60 mph; wind tunnel command following: open and closed loop error at 60 mph; wind tunnel flutter suppression: open loop flutter speed; and wind tunnel flutter suppression: closed loop state cost curves
A multiple catheter technique for studies or hepatic metabolism and blood flow in dogs with portacaval transposition
A technique is described for in vivo hepatic metabolic studies, employing a multiple catheterization technique in dogs with chronic portacaval transposition. The animals are studied in the unanesthetized state immediately after the insertion of catheters through peripheral cut-downs. The gradient of metabolites entering and leaving the liver can be measured concomitantly with hepatic plasma flow. Additional simultaneous gradients can be obtained across the splanchnic capillary bed, or the hindquarters. Drugs can be introduced into the circulation by a systemic route or by primary injection into the hepatic circulation. The advantages of this approach compared to other methods of evaluating moment to moment hepatic function are discussed. © 1962
Cosmic ray modulation and turbulent interaction regions near 11 AU
When Voyager 2 was near 11 AU, the counting rate of nuclei approx 75 MeV/nucleon decreased during the interval from July, 1982 to November, 1982, and it increased thereafter until August, 1983. A decrease in cosmic ray flux was generally associated with the passage of an interaction region in which the magnetic field strength B was higher than that predicted by the spiral field model, B sub p. Several large enhancements in B/B sup p were associated with merged interaction regions which probably resulted from the interaction of two or more distinct flows. During the passage of interaction regions the cosmic ray intensity decreased at a rate proportional to (B/B sup p -1), and during the passage of rarefaction regions (where B/B sup p 1) the cosmic ray intensity increased at a constant rate. The general form of the cosmic ray intensity profile during this approx 13 month minicycle can be described by integrating these relations using the observed B(t). Latitudinal variations of the interaction regions and of the short-term cosmic ray variations were identified
The influence of emotional reaction on help seeking by victims of school bullying
Research has started to focus on how victims of school bullying cope, but there is still very little understanding if why pupils cope in one way and not another. This paper aimed to examine the effects of gender, school-stage, frequency of victimization and different emotions (anger, vengeance, self-pity, indifference, and helplessness) upon the choice of social support that children report using. Questionnaires were completed by 6282 Maltese schoolchildren aged between 9 and 14 years old. Analyses revealed that specific patterns of emotion and victimization predict whether pupils report using certain sources of social support. Results are discussed in relation to their relevance for possible intervention, future research needs and implications for the theoretical framework used
TB116: Integrated Systems for Managing Potatoes in the Northeast
This technical bulletin presents the results of a research project developed to determine the feasibility of using an integrated pest management (IPM) system to improve economic and environmental benefits for the Northeast region. Research was conducted to develop and evaluate IPM techniques. These techniques were then tested, improved, and implemented in pilot programs on commercial potato farms in Suffolk County and Steuben County, New York, and Aroostook County, Maine.https://digitalcommons.library.umaine.edu/aes_techbulletin/1076/thumbnail.jp
Artificial reef for artisanal fisheries enhancement - an attempt off Trivandrum coast
Several demersal fishes arc found to congregate
in the vicinity of submerged objects such as reefs, logs,
ship-wrecks and rock out-crops where plants and
bcnthic animals flourish than in areas where the bottom
is flat and barren. These communities serve as food for
larger predators. Submerged objects may, at times,
provide shelter and even spawning locations for manya-
fish. Underwater observations made by divers while
retrieving portions of submerged vessels also report
that such habitats harbour considerable concentration
of fishe
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