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991.
John D. Monnier Stefan Kraus Michael J. Ireland Fabien Baron Amelia Bayo Jean-Philippe Berger Michelle Creech-Eakman Ruobing Dong Gaspard Duchêne Catherine Espaillat Chris Haniff Sebastian Hönig Andrea Isella Attila Juhasz Lucas Labadie Sylvestre Lacour Stephanie Leifer Antoine Merand Ernest Michael Stefano Minardi Christoph Mordasini David Mozurkewich Johan Olofsson Claudia Paladini Romain Petrov Jörg-Uwe Pott Stephen Ridgway Stephen Rinehart Keivan Stassun Jean Surdej Theo ten Brummelaar Neal Turner Peter Tuthill Kerry Vahala Gerard van Belle Gautam Vasisht Ed Wishnow John Young Zhaohuan Zhu 《Experimental Astronomy》2018,46(3):517-529
The Planet Formation Imager (PFI, www.planetformationimager.org) is a next-generation infrared interferometer array with the primary goal of imaging the active phases of planet formation in nearby star forming regions. PFI will be sensitive to warm dust emission using mid-infrared capabilities made possible by precise fringe tracking in the near-infrared. An L/M band combiner will be especially sensitive to thermal emission from young exoplanets (and their disks) with a high spectral resolution mode to probe the kinematics of CO and H2O gas. In this paper, we give an overview of the main science goals of PFI, define a baseline PFI architecture that can achieve those goals, point at remaining technical challenges, and suggest activities today that will help make the Planet Formation Imager facility a reality. 相似文献
992.
Zorigt Munkhtsetseg Myagmar Khulan Orkhonselenge Alexander van Beek Eelco Kwadijk Jaap Tsogtbayar Jargaltulga Yamkhin Jambaljav Dechinlkhundev Dorjsuren 《Environmental Earth Sciences》2020,79(12):1-1
The Editors-in-Chief of Environmental Earth Sciences are issuing an editorial expression of concern to alert readers that this article. 相似文献
993.
Katja K. Hirsch Magdalena Scheck-Wenderoth Jan-Diederik van Wees Gesa Kuhlmann Douglas A. Paton 《Marine and Petroleum Geology》2010
The Orange Basin offshore southwest Africa appears to represent a classical example of continental rifting and break up associated with large-scale, transient volcanism. The presence of lower crustal bodies of high seismic velocities indicates that large volumes of igneous crust formed as a consequence of lithospheric extension. 相似文献
994.
The subject of measuring the performance of registries has been a topic of policy discussions in recent years at the regional level due to the recasting of the European Union (EU) port state control (PSC) directive which introduces incentives for flags which perform better. Since the current method used in the EU region entails some shortcomings, it has therefore been the subject of substantial scrutiny. Furthermore, the International Maritime Organization (IMO) developed a set of performance indicators which however lacks the ability to measure compliance as set out in one of its strategic directions towards fostering global compliance. This article develops a methodology to measure flag state performance which can be applied on the regional or global level and to other areas of legislative interest (e.g. recognized organizations, Document of Compliance Companies). The proposed methodology overcomes some of the shortcomings of the present method and presents a more refined, less biased approach of measuring performance. To demonstrate its usefulness, it is applied to a sample of 207,821 observations for a 3-year time frame and compared to the current method. 相似文献
995.
The Tasmanian rock lobster industry has been managed by Individually Transferable Quotas (ITQs) and several input control measures since 1998. In this study, nine years of rock lobster fishing business data were used to categorise the catch and quota ownership traits and examine the response to the introduction of ITQ management. More specifically the study investigates how profit drivers moderated industry structure change. 相似文献
996.
José Guerreiro Aldo Chircop Catarina Grilo Ana Viras Raquel Ribeiro Rudy van der Elst 《Marine Policy》2010
International conservation efforts and cooperation are increasingly necessary, particularly at an ecoregion level, for the achievement of international targets for protecting biodiversity and degradation of ecosystems. Whereas more than 11 percent of land is protected, less than 1 percent of marine space is similarly protected. Transboundary networks of marine protected areas and transboundary marine protected areas (TBMPAs) are an essential form of cooperation for meeting these international targets. This paper explores the diplomatic and political options for regional and sub-regional cooperation between Tanzania, Mozambique, and South Africa, for the establishment of transboundary conservation mechanisms in the Eastern African Marine Ecoregion (EAME). Five options for the establishment and management of these mechanisms are presented, together with actions to be taken to facilitate cooperation. The paper deal with a proposed strategy for the implementation of transboundary conservation mechanisms, focusing on TBMPAs, between the three countries at a biogeographical/sub-regional level, supported by lessons learnt in other transboundary marine conservation experiences. The paper concludes that although political will may exist among States sharing borders to establish TBMPAs, the complexity of dealing with sub-regional realities is a difficult obstacle to overcome in a single step. The situation at each border must be taken into account in order that different multi-scale and multivariate solutions, supported by a common baseline will ultimately converge in a common trilateral framework. Finally, a two-step approach seems to be in course with the declaration (October 2009) of a TBMPA linking Ponta do Ouro in Mozambique to iSimangaliso Wetland Park in South Africa, following one of the options formerly presented. 相似文献
997.
Tidal channels and inlets in alluvial environments are interconnected dynamic systems that react to changing physical conditions (such as sea level rise) as well as to anthropogenic impact (such as dredging and bank protection works). Past research resulted in an empirical equilibrium relationship for inlets between the tidal prism (P) and the cross-sectional area in a tidal inlet (A). Constant PA relationships were found along several tidal basins. 相似文献
998.
Olivier R. van Lier Richard A. Fournier Robert L. Bradley Nelson Thiffault 《International Journal of Applied Earth Observation and Geoinformation》2009,11(5):334-343
Invasive ericaceous shrubs (e.g. Kalmia angustifolia, Rhododendron groenlandicum, Vaccinium spp.) may reduce the regeneration and early growth of black spruce (Picea mariana) seedlings, the most economically important boreal tree species in Quebec. Our study focused, therefore, on developing a method for mapping ericaceous shrubs from satellite images. The method integrates very high resolution satellite imagery (IKONOS) to guide classifiers applied to medium resolution satellite imagery (Landsat-TM). An object-oriented image classification approach was applied using Definiens eCognition software. An independent ground survey revealed 80% accuracy at the very high spatial resolution. We found that the partial use (70%) of classified polygons derived from the IKONOS images were an effective way to guide classification algorithms applied to the Landsat-TM imagery. The results of this latter classification (78.4% overall accuracy) were assessed by the remaining portion (30%) of unused very high resolution classified polygons. We further validated our method (65.5% overall accuracy) by assessing the correspondence of an ericaceous cover classification scheme done with a Landsat-TM image and results of our ground survey using an independent set of 275 sample plots. Discrimination of ericaceous shrub cover from other land cover types was achieved with precision at both spatial resolutions with producer accuracies of 87.7% and 79.4% from IKONOS and Landsat, respectively. The method is weaker for areas with sparse cover of ericaceous shrubs or dense tree cover. Our method is adapted, therefore, for mapping the spatial distribution of ericaceous shrubs and is compatible with existing forest stand maps. 相似文献
999.
Geometry-free undifferenced, single and double differenced analysis of single frequency GPS, EGNOS and GIOVE-A/B measurements 总被引:3,自引:1,他引:2
This paper demonstrates a geometry-free GNSS measurement analysis approach and presents results of single frequency GPS, EGNOS
and GIOVE short and zero baseline measurements. The purpose is to separate the different contributions to the measurement
noise of pseudo range code and carrier phase observations at the receiver. The influence of multipath on the different combinations
of observations is also determined. Quantitative results are presented for the thermal code and phase measurement noise and
for the correlation between the observations. Comparison of the results with theoretical approximations confirms the validity
of the used approach. Results from field measurements clearly show less thermal noise on the Galileo E1BC observations than
on the GPS L1C/A observations due to the new signal modulation. The feasibility of ambiguity resolution with a geometry-free
model is also discussed including the significant impact of multipath thereon. 相似文献
1000.
Conrad S. Chapman Gabriele Capodaglio Clara Turetta Constant M.G. van den Berg 《Marine environmental research》2009,67(1):17-24
Benthic fluxes of copper, copper complexing ligands and thiol compounds in the shallow waters of Venice Lagoon (Italy) were determined using benthic chambers and compared to porewater concentrations to confirm their origin. Benthic copper fluxes were small due to small concentration differences between the porewaters and the overlying water, and the equilibrium concentration was the same at both sites, suggesting that the sediments acted to buffer the copper concentration. Thiol fluxes were ~10 × greater at 50–60 pmol cm?2 h?1, at the two sites. Porewater measurements demonstrated that the sediments were an important source of the thiols to the overlying waters. The overlying waters were found to contain at least two ligands, a strong one, L1 (log K′CuL1 = 14.2) and a weaker one, L2 (log K′CuL2 = 12.5). The concentration of L1 remained relatively constant during the incubation and similar to that of copper, whereas that of L2 was in great excess of copper, its concentration balanced by porewater releases and breakdown, probably due to uptake by microorganisms, similar to that of the thiol compounds. Similarity of the thiol and L2 concentrations and similar complex stability with copper suggest that L2 was dominated by the thiols. The free copper concentration ([Cu´]) in the Lagoon waters was lowered by a factor of 105 as a result of the organic complexation. 相似文献