17,103 research outputs found

    ANALYZING TECHNICAL AND ECONOMIC INTERRELATIONSHIPS IN HAWAII'S LONGLINE FISHERY

    Get PDF
    This paper provides an analysis of technical and economic interrelationships among species harvested in Hawaii's pelagic longline fishery. The results indicate that this multispecies fishery is characterized by a joint production process, meaning that the regulation of one species would affect the harvest of other species. It implies that a single species regulation may not be appropriate in managing the longline fishery. Estimates of own-price output supply elasticities suggest that fisher's decisions on the amounts of each species harvested are independent of own expected prices. However, as evidenced by the estimates of cross-price elasticities, there are a number of significant technical-economic interactions among species. Failing to reject the null hypothesis of input-output separability suggests that management of the entire fishery as a whole by partial area/seasonal closure or by a 'limited entry' system as in the past is justified instead of regulating a few key species.Resource /Energy Economics and Policy,

    Impact of the Desert dust on the summer monsoon system over Southwestern North America

    Get PDF
    The radiative forcing of dust emitted from the Southwest United States (US) deserts and its impact on monsoon circulation and precipitation over the North America monsoon (NAM) region are simulated using a coupled meteorology and aerosol/chemistry model (WRF-Chem) for 15 years (1995–2009). During the monsoon season, dust has a cooling effect (−0.90 W m<sup>−2</sup>) at the surface, a warming effect (0.40 W m<sup>−2</sup>) in the atmosphere, and a negative top-of-the-atmosphere (TOA) forcing (−0.50 W m<sup>−2</sup>) over the deserts on 24-h average. Most of the dust emitted from the deserts concentrates below 800 hPa and accumulates over the western slope of the Rocky Mountains and Mexican Plateau. The absorption of shortwave radiation by dust heats the lower atmosphere by up to 0.5 K day<sup>−1</sup> over the western slope of the Mountains. Model sensitivity simulations with and without dust for 15 summers (June-July-August) show that dust heating of the lower atmosphere over the deserts strengthens the low-level southerly moisture fluxes on both sides of the Sierra Madre Occidental. It also results in an eastward migration of NAM-driven moisture convergence over the western slope of the Mountains. These monsoonal circulation changes lead to a statistically significant increase of precipitation by up to ~40 % over the eastern slope of the Mountains (Arizona-New~Mexico-Texas regions). This study highlights the interaction between dust and the NAM system and motivates further investigation of possible dust feedback on monsoon precipitation under climate change and the mega-drought conditions projected for the future

    Wave Propagation in Gravitational Systems: Completeness of Quasinormal Modes

    Get PDF
    The dynamics of relativistic stars and black holes are often studied in terms of the quasinormal modes (QNM's) of the Klein-Gordon (KG) equation with different effective potentials V(x)V(x). In this paper we present a systematic study of the relation between the structure of the QNM's of the KG equation and the form of V(x)V(x). In particular, we determine the requirements on V(x)V(x) in order for the QNM's to form complete sets, and discuss in what sense they form complete sets. Among other implications, this study opens up the possibility of using QNM expansions to analyse the behavior of waves in relativistic systems, even for systems whose QNM's do {\it not} form a complete set. For such systems, we show that a complete set of QNM's can often be obtained by introducing an infinitesimal change in the effective potential

    Perturbative Approach to the Quasinormal Modes of Dirty Black Holes

    Get PDF
    Using a recently developed perturbation theory for uasinormal modes (QNM's), we evaluate the shifts in the real and imaginary parts of the QNM frequencies due to a quasi-static perturbation of the black hole spacetime. We show the perturbed QNM spectrum of a black hole can have interesting features using a simple model based on the scalar wave equation.Comment: Published in PR

    Singular behaviour of the electromagnetic field

    Full text link
    The singularities of the electromagnetic field are derived to include all the point-like multipoles representing an electric charge and current distribution. Firstly derived in the static case, the result is generalized to the dynamic one. We establish a simple procedure for passing from the first, to the second case.Comment: Latex, 21.pages, no figure

    Quasi-Normal Mode Expansion for Linearized Waves in Gravitational Systems

    Full text link
    The quasinormal modes (QNM's) of gravitational systems modeled by the Klein-Gordon equation with effective potentials are studied in analogy to the QNM's of optical cavities. Conditions are given for the QNM's to form a complete set, i.e., for the Green's function to be expressible as a sum over QNM's, answering a conjecture by Price and Husain [Phys. Rev. Lett. {\bf 68}, 1973 (1992)]. In the cases where the QNM sum is divergent, procedures for regularization are given. The crucial condition for completeness is the existence of spatial discontinuities in the system, e.g., the discontinuity at the stellar surface in the model of Price and Husain.Comment: 12 pages, WUGRAV-94-

    Radiometric calibration and processing procedure for reflective bands on LANDSAT-4 protoflight Thematic Mapper

    Get PDF
    The radiometric subsystem of NASA's LANDSAT-4 Thematic Mapper (TM) sensor is described. Special emphasis is placed on the internal calibrator (IC) pulse shapes and timing cycle. The procedures for the absolute radiometric calibration of the TM channels with a 122-centimeter integrating sphere and the transfer of radiometric calibration from the channels to the IC are reviewed. The use of the IC to calibrate TM data in the ground processing system consists of pulse integration, pulse averaging, IC state identification, linear regression analysis, and histogram equalization. An overview of the SCROUNGE-era (before August 1983) method is presented. Procedural differences between SCROUNGE and the TIPS-era (after July 1983) and the implications of these differences are discussed

    Characterization of radiometric calibration of LANDSAT-4 TM reflective bands

    Get PDF
    Prelaunch and postlaunch internal calibrator, image, and background data is to characterize the radiometric performance of the LANDSAT-4 TM and to recommend improved procedures for radiometric calibration. All but two channels (band 2, channel 4; band 5, channel 3) behave normally. Gain changes relative to a postlaunch reference for channels within a band vary within 0.5 percent as a group. Instrument gain for channels in the cold focal plane oscillates. Noise in background and image data ranges from 0.5 to 1.7 counts. Average differences in forward and reverse image data indicate a need for separate calibration processing of forward and reverse scans. Precision is improved by increasing the pulse integration width from 31 to 41 minor frames, depending on the band
    • …
    corecore