Automatic Semivariogram Modeling by Convolutional Neural Network     

Jo  Honggeun  Pyrcz  Michael J. 《Mathematical Geosciences》2022,54(1):177-205

Mathematical Geosciences - Modeling the semivariogram to characterize spatial continuity requires expert geostatistical knowledge and domain expertise about the spatial phenomenon of interest....  相似文献   

Distribution and feeding patterns of juvenile parrotfish on algal‐dominated coral reefs          下载免费PDF全文

João L.L. Feitosa  Beatrice P. Ferreira 《Marine Ecology》2015,36(3):462-474

By the consumption of algae, parrotfishes open space for young coral settlement and growth, thus playing a central role on the maintenance of coral reefs. However, juvenile parrotfish ecology is often overlooked due to the difficulty discerning species during this phase. Herein, we present the first attempt to investigate changes in habitat use and diet that happen to juveniles of the Redeye parrotfish Sparisoma axillare, focusing on four zones within an algal‐dominated reef: the macroalgal beds, back reef, reef flat, and fore reef. Smaller S. axillare juveniles (<5 cm) preferred to inhabit the macroalgal beds and the reef flat, whereas juveniles larger than 5 cm were more abundant in the back and fore reefs due to distinct post‐settlement habitat conditions. Aggressive interactions with the territorial damselfish Stegastes fuscus were the primary driving factor of juvenile distribution and feeding rates. Attack rates increased with juvenile size and the lowest bite rates were observed in zones with higher densities of territorial damselfish. In previous studies, the persistence of parrotfish recruits in habitats dominated by damselfish was reduced, but newly settled parrotfish occurred more densely within the damselfish domain by behaving as a cryptic reef fish. As these juveniles grew, their bite rates increased, a change associated with a shift from cryptic to roving behavior. Feeding preferences were determined by substrate cover, where juveniles fed on available food sources in each habitat. Juveniles relied on jointed calcareous algae in habitats dominated by these algae, a pattern not observed for thick leathery algae. Filamentous algae were the preferred food for smaller fish; for individuals greater than 10 cm, a higher ingestion of sand was observed. Most studies evaluating the functional role of parrotfish do not consider species feeding preferences. However, the potential for a species to turn an impacted reef back to a coral‐dominated phase is influenced by their food selection, which is dependent on the algal species composition.  相似文献   

Mass segregation in young clusters: observational biases     

Joana Ascenso  João Alves  Maria Teresa V. T. Lago 《Astrophysics and Space Science》2009,324(2-4):113-119

We investigate the validity of the mass-segregation indicators most commonly used in the analysis of young stellar clusters. We construct and analyze synthetic massive clusters with a standard, fully sampled stellar initial mass function and a King density distribution function. We find that the commonly used indicators are highly sensitive to the effects of incompleteness in observational data, and that completeness determinations do not provide satisfactory corrections, leading to results that may be severely biased toward mass segregation.  相似文献   

The Value of Information in Spatial Decision Making   总被引：1，自引：1，他引：0  

Debarun Bhattacharjya  Jo Eidsvik  Tapan Mukerji 《Mathematical Geosciences》2010,42(2):141-163

Experiments performed over spatially correlated domains, if poorly chosen, may not be worth their cost of acquisition. In this paper, we integrate the decision-analytic notion of value of information with spatial statistical models. We formulate methods to evaluate monetary values associated with experiments performed in the spatial decision making context, including the prior value, the value of perfect information, and the value of the experiment, providing imperfect information. The prior for the spatial distinction of interest is assumed to be a categorical Markov random field whereas the likelihood distribution can take any form depending on the experiment under consideration. We demonstrate how to efficiently compute the value of an experiment for Markov random fields of moderate size, with the aid of two examples. The first is a motivating example with presence-absence data, while the second application is inspired by seismic exploration in the petroleum industry. We discuss insights from the two examples, relating the value of an experiment with its accuracy, the cost and revenue from downstream decisions, and the design of the experiment.  相似文献   

Is there a win–win scenario for marine nature conservation? A case study of Lyme Bay,England     

Siân E. Rees  Martin J. Attrill  Melanie C. Austen  Steven C. Mangi  Jo P. Richards  Lynda D. Rodwell 《Ocean & Coastal Management》2010,53(3):135-145

A statutory two hundred and six square kilometre ‘closed area’ in Lyme Bay, South West England entered into force on the 11 July 2008 to protect the reef substrate and the associated biodiversity from the impacts of trawling and dredging with heavy demersal fishing gear. This case study provides an example of how the ecosystem approach has been incorporated into decision making for marine nature conservation and shows that despite sound ecological knowledge of a marine area, the current reliance on traditional neo-classical economic valuations for marine spatial planning can obscure other issues pertinent to the ecosystem approach. With the Government seeking win–win scenarios for stakeholders in the designation of Marine Conservation Zones under the Marine and Coastal Access Act, experience of marine spatial planning in Lyme Bay has revealed that a win–win must be a long-term goal based on a thorough evaluation of the environmental, social and economic values of marine biodiversity.  相似文献   

Global Paleomagnetic Database Supplement number one: Update to 1992   总被引：3，自引：0，他引：3  

Michael W. McElhinny  Jo Lock 《Surveys in Geophysics》1993,14(3):303-329

This is the first Supplement to the Manual, first published inSurveys in Geophysics in 1991 and issued also as a separate volume, for the operation of the Global Paleomagnetic Database (GPMDB) using ORACL E. Minor changes have been made to the database structure as foreshadowed in the Manual and major extensions have been made to the MENU involving a new set of command files. These and other changes are detailed and should be read in conjunction with the original Manual. This latest Version 2.2 of the the GPMDB now contains over 7000 results with over 2600 references and covers all published data world-wide up to the end of 1992. Diskettes containing the new data set and accompanying program files may be obtained, as before, from World Data Center A in Boulder, Colorado. Both the updated data set and program files completely replace the original Version 1.4 released in August 1991.  相似文献   

International Symposium on Satellite Geodesy in Budapest     

I. Joó 《Journal of Geodesy》1977,51(4):249-252

  相似文献   

Author index volume 36     

Annie Michard-Vitrac  Joël Lancelot  Claude J. Allègre  Stephen Moorbath 《Earth and Planetary Science Letters》1977,36(3):449-451

Using the single zircon technique, two areas which give some of the oldest ages on earth have been investigated, namely the Minnesota River Valley and West Greenland.The results on single zircons from the Minnesota River Valley and from the Amîtsoq gneisses (West Greenland) do not differ significantly from the results of Farhat (1975) and Baadsgaard (1973) at about 3.3 and 3.65 b.y., respectively.The U-Pb analyses of single zircons from acid boulders from the conglomerate unit at Isua (West Greenland) yield the oldest age so far reported for a terrestrial rock, namely 3.824_?0.009^+0.012 b.y.  相似文献   

The worldwide character of the 1969–1970 impulse of the secular acceleration rate     

Jean-Louis Le Mouël  Joël Ducruix  Chau Ha Duyen 《Physics of the Earth and Planetary Interiors》1982,28(4):337-350

This paper continues earlier studies to ascertain whether the distribution of the 1969–1970 jump of the secular variation rate has a worldwide character. The geometry of the jump presents some similarities with the geometry of the secular variation itself. We give a new estimation of the westward drift rate and information about spatial and temporal variations of the secular variation field.  相似文献   

United Nations office for outer space affairs GNSS web-pages     

Jo?o?Francisco?Galera?MonicoEmail author 《GPS Solutions》2004,8(2):112-114

In this article, Dr. J.F.G. Monico introduces the on-line resources at the website of the UN Office for Outer Space Affairs, including the web-based GPS resources and their technical background information. Its purpose is to inform the reader about the data, software, electronic documents that are available on-line. This article is coordinated by Dr. Jinling Wang, University of New South Wales, Sydney. Comments and suggestions are appreciated (Jinling.Wang@unsw.edu.au).  相似文献