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Autor Borregon, J. L.; Paredes, C.; Elorza, F. J.
Titel New algorithms for the statistical modelling of geological heterogeneous media: Comparative results Typ Buch
Jahr 1995 Publikation Kurztitel der Zeitschrift
Band Ausgabe Seiten
Schlüsselwörter algorithms-; statistical-analysis; heterogeneity-; radioactive-waste-disposal; geology-; simulation-; aquifers-; geochemistry-; groundwater-pollution; pollution-control; waste-disposal-sites; environmental-protection
Zusammenfassung The characterization of an heterogeneous geological media can be approached by means of an statistical treatment of the field data. This lets us know its spatial variability behaviour, in probability terms. The algorithms presented in this work belongs to the scope of simulation of geological heterogeneous random fields. The aim of that characterization is related with the reseach studies of nuclear waste repositories in deep geological structures. Several stochastic generation algorithms are presented, based in the geostatistical regionalized variable, fractal geometry, and spectral Fourier theories. Some of them are deeply exposed here to their understanding. As a result of the paper, some comparative schemes are showed with numerical, geostatistical and spectral analysis of the implicit autorregresive generation methods.
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Rufnummer Signatur 241
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Autor Fotland, A.; Mehl, S.; Sunnanaa, K.
Titel Methods of index calculation and presentation of fish abundance data using standard computer programs Typ Buch
Jahr 1995 Publikation Kurztitel der Zeitschrift
Band Ausgabe Seiten
Schlüsselwörter fishery-management; fishery-statistics; stock-assessment
Zusammenfassung Standard 0-group indices and distribution maps are now produced based on hand-drawn maps using AutoCad with some additional procedures. This paper briefly describes the method. The paper further describes ways of importing coastlines and survey data directly into standard computer programs such as AutoCad and SAS. Standard methods are used for gridding data, producing isolines and further calculation of abundance indices and presentation of distributions. Interactive editing of distribution maps are made, which makes corresponding automatic updating of indices possible.
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Rufnummer Signatur 435
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Autor Hiramatsu, K.; Akamine, T.; Kitada, S.
Titel Effectiveness of partial likelyhood of estimating fish mortality rates from tag recoveries and the stock composition in the mixed population based on genetic data Typ Zeitschrift, Artikel
Jahr 1995 Publikation NIPPON SUISAN GAKKAISHI 1995 vol. 61 Kurztitel der Zeitschrift
Band Ausgabe 3 Seiten
Schlüsselwörter stock-assessment; tagging-; genomes-; fishing-mortality; mixing-ratio; mathematical-analysis
Zusammenfassung Because of the simplicity of calculation and the availability of evaluating the precision of the estimates, a partial likelihood approach has been used for estimating fish mortality rates from tag recoveries and the stock composition in the mixed population based on genetic data. We compare the partial likelihood estimator with the full likelihood estimator, and find that under some conditions, both estimators are the same. The above applications meet the conditions and hence the estimates using the partial likelihood are the same as the ones using the full likelihood. In this case, the partial likelihood approach is quite useful.
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Rufnummer Signatur 676
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Autor Leshkevich, G. A.
Titel Great Lakes CoastWatch program update Typ Buch
Jahr 1995 Publikation Kurztitel der Zeitschrift
Band Ausgabe Seiten
Schlüsselwörter North-America,-Great-Lakes; monitoring-; decision-making; satellite-technology; coastal-waters; ecosystems-; data-transmission; environmental-monitoring; satellite-sensing
Zusammenfassung As the CoastWatch regional node for the Great Lakes, the Great Lakes Environmental Research Laboratory (GLERL) is working to obtain and/or develop and deliver environmental data and products for near real-time monitoring of the Great Lakes to support environmental science and decision making. In support of this goal, GLERL is providing access to near real-time and retrospective satellite observations and in-situ data for the Great Lakes to Federal, state, and local agencies and academic institutions. There are currently nearly 40 regional CoastWatch users. The goals and objectives of the Great Lakes CoastWatch Program directly support agency statutory responsibilities in estuarine and marine science, living marine resource protection, and ecosystem monitoring and management. GLERL is currently receiving an enhanced digital image product suite of 26 images including satellite derived surface-temperature, visible and near-infrared reflectance, brightness temperatures, satellite and solar zenith angle data, and cloud masks from the NOAA-12 satellite. These products are downloaded from the NOAA Ocean Products Center (OPC) via INTERNET on a daily basis and archived at GLERL. Over 32,000 image products have been received and archived since becoming the Great Lakes CoastWatch Node in 1990. GOES-8 data is also currently being received.
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Rufnummer Signatur 1005
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Autor Mertz, G.; Myers, R. A.
Titel Estimating the predictability of recruitment Typ Zeitschrift, Artikel
Jahr 1995 Publikation Fish. Bull Kurztitel der Zeitschrift
Band 93 Ausgabe 4 Seiten 657-665
Schlüsselwörter recruitment-; mortality-; developmental-stages; fishery-biology; fishery-management; environmental-factors; stock-assessment; Pisces-; population-dynamics; models-
Zusammenfassung A simple analytical technique is developed for estimating the predictability of recruitment, that is, correlations between recruitment and stage-specific mortalities or abundances. The method requires the input of estimates of the variability of stage-specific mortalities, which may be calculated from mean stage-specific mortalities by applying a published regression. It is shown that modification of this regression to compensate for sampling error in field measurements of abundance significantly reduces the estimated standard deviation of log-recruitment, which is an important factor in the predictability calculations. It is concluded that the prospects for predicting recruitment from egg or larval surveys or from environmental variables are quite poor for fish stocks showing the typical distribution of mortality across stages.
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Rufnummer Signatur 1090
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Autor Porch, C. E.
Titel Trajectory-based approaches to estimating velocity and diffusion from tagging data Typ Zeitschrift, Artikel
Jahr 1995 Publikation Fish. Bull Kurztitel der Zeitschrift
Band 93 Ausgabe 4 Seiten 694-709
Schlüsselwörter dispersion-; migrations-; tagging-; Pisces-; swimming-; models-; dispersal-; migration-
Zusammenfassung Several new models are developed to estimate the velocity and diffusion of a population from tagging data. The new estimators apply the inverse principle to the individual trajectories of recovered tags rather than to their local abundance. These models require fewer assumptions and less information than do published abundance-based methods. Techniques are presented for a variety of circumstances, and both discrete and continuous parameterizations of the velocity field are included. The sensitivity of the estimators to violations of the assumptions was examined numerically by using stochastic simulations. The results suggest that the estimators are fairly robust but may fail under certain conditions. Extensions to accommodate these situations are discussed.
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Rufnummer Signatur 1295
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Autor Quartly, G. D.
Titel Altimeter repeat-track analysis -- a comparison of various algorithms for producing the mean profile Typ Zeitschrift, Artikel
Jahr 1995 Publikation J. Atmos. Ocean. Technol Kurztitel der Zeitschrift
Band 12 Ausgabe 3 Seiten 674-686
Schlüsselwörter dynamical-oceanography; remote-sensing; satellite-altimetry; sea-level-measurement; geoid-; geostrophic-transport; statistical-analysis; errors-
Zusammenfassung Sea surface height may be measured by a satellite-borne altimeter and its along-track slope used to infer geostrophic currents. A major difficulty is that, in general, the local geoid and satellite orbit are not known to the accuracy desired. Thus, comparison is often made between repeat flights of an altimeter along fixed ground tracks in order to infer the changes in the currents. In practice, it is convenient to calculate a mean height profile from many repeat passes and use this as a reference, so that individual altimetric profiles yield variations about this mean. It is thus important to derive a high-quality reliable estimate of the altimetric mean in order to minimize the errors in the inferred flows for the individual repeats. This work examines various methods for deriving the mean profile.
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Rufnummer Signatur 1302
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Autor Walters, C.
Titel Estimation of historical stock sizes and recruitment anomalies from relative abundance time series Typ Zeitschrift, Artikel
Jahr 1995 Publikation Can. J. Fish. Aquat. Sci. J. Can. Sci. Halieut. Aquat Kurztitel der Zeitschrift
Band 52 Ausgabe 7 Seiten 1523-1534
Schlüsselwörter stock-assessment; approximation-; anomalies-; recruitment-; abundance-; growth-; survival-; algorithms-; fishery-management; marine-fisheries
Zusammenfassung Often only simple relative abundance time series and basic growth and (or) survival estimates are available for assessing impacts of fishing and environmental factors. Assessment then involves fitting production models to the series, while forcing the model with observed catch or effort series. A key uncertainty in this approach is how to deal with recruitment variations due to factors other than stock size. A dynamic programming algorithm can be used to compute maximum likelihood estimates of the recruitment anomaly sequence, given prior knowledge of growth parameters, the natural survival rate, and proportion of the variation in the relative abundance index that is due to abundance measurement errors.
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Rufnummer Signatur 1779
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Autor Angermeier, P. L.; Smogor, R. A.
Titel Estimating number of species and relative abundances in stream-fish communities: Effects of sampling effort and discontinuous spatial distributions Typ Zeitschrift, Artikel
Jahr 1995 Publikation Can. J. Fish. Aquat. Sci. J. Can. Sci. Halieut. Aquat Kurztitel der Zeitschrift
Band 52 Ausgabe 5 Seiten 936-949
Schlüsselwörter Fisch, Fließgewässer, Habitat, Verbreitung
Zusammenfassung The authors sampled fishes and measured microhabitat in series of contiguous habitat units (riffles, runs, pools) in three Virginia streams. Monte Carlo simulations were used to construct hypothetical series of habitat units, then examined how number of species, similarity in relative abundances, and number of microhabitats accumulated with increasing number of habitat units (i.e., sampling effort). The curves indicated that 90% of the species present were usually found by sampling 5 to 14 habitat units (stream length of 22-67 stream widths). Estimates of species relative abundances required less sampling effort for a given accuracy than estimates of number of species. Rates of species accumulation (with effort) varied among streams and reflected discontinuity in species distributions among habitat units. Most discontinuity seemed to be due to low population density rather than to habitat selectivity. Results from an Illinois stream corroborated our findings from Virginia, and suggested that greater sampling effort is needed to characterize fish community structure in more homogeneous stream reaches.
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Notizen (down) Natl. Biol. Serv., Virginia Coop. Fish Wildl. Res. Unit, Virginia Polytech. Inst., Blacksburg, VA 24061-0321, USA Geprüft nein
Rufnummer 620 Signatur 2414
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Autor Born, O.
Titel Untersuchungen zur Wirksamkeit von Fischaufstiegshilfen am unterfränkischen Main Typ Buch
Jahr 1995 Publikation Institut für Tierwissenschaften Kurztitel der Zeitschrift
Band Ausgabe Seiten 302
Schlüsselwörter Fisch, Wanderung, Fischaufstiegshilfe
Zusammenfassung
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Rufnummer Signatur 238
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