A stock rebuilding algorithm featuring risk assessment and an optimization strategy of single or multispecies fisheries     

Groger  Joachim P.; Rountree  Rodney A.; Missong  Martin; Ratz  Hans-Joachim 《ICES Journal of Marine Science》2007,64(6):1101-1115

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Migration dynamics of clupeoids in the Schelde estuary: A stable isotope approach   总被引：3，自引：0，他引：3  

Jef Guelinckx  Joachim Maes  Loreto De Brabandere  Frank Dehairs  Frans Ollevier 《Estuarine, Coastal and Shelf Science》2006,66(3-4):612-623

Large numbers of young of the year herring (Clupea harengus L.) and sprat (Sprattus sprattus (L.)) typically enter and remain within North Sea estuaries during the winter months. The main purpose of this study was to examine their migration dynamics between the North Sea and the Schelde estuary using C and N stable isotopes. Prior to this, stomach contents were used to verify the isotopic differences between the food sources at the sampling stations. From May 2000 to April 2001 fish were collected monthly in the upper and lower estuary. Muscle tissue and stomach contents were analyzed for δ¹³C and δ¹⁵N using an EA-IRMS. Based on the stomach contents, it was demonstrated that δ¹⁵N could not be used as a tracer for fish migration because the longitudinal estuarine δ¹⁵N gradient had reversed completely during autumn. The δ¹³C gradient, however, was found to be reliable for studying fish movement in the Schelde estuary.Seasonal movements of clupeoids in the Schelde estuary were analyzed by separating the temporal abundance patterns into migration groups based on their muscle isotopic composition. Immigration and emigration seem to occur continuously throughout the year. Most exchange occurred in November. During winter, immigration remained high but gradually decreased. Although the herring and sprat abundance further declined in the estuary during February and March, large seaward emigration was not fully demonstrated. As temporal overlap between immigration and emigration is concluded the results support the hypothesis that migration to estuarine nurseries is individually based.  相似文献   

VGDI – Advancing the Concept: Volunteered Geo‐Dynamic Information and its Benefits for Population Dynamics Modeling          下载免费PDF全文

Christoph Aubrecht  Dilek Özceylan Aubrecht  Joachim Ungar  Sérgio Freire  Klaus Steinnocher 《Transactions in GIS》2017,21(2):253-276

The concept of Volunteered Geographic Information (VGI) has progressed from being an exotic prospect to making a profound impact on GIScience and geography in general, as initially anticipated. However, while massive and manifold data is continuously produced voluntarily and applications are built for information and knowledge extraction, the initially introduced concept of VGI lacks certain methodological perspectives in this regard which have not been fully elaborated. In this article we highlight and discuss an important gap in this concept, i.e. the lack of formal acknowledgment of temporal aspects. By coining the proposed advanced framework ‘Volunteered Geo‐Dynamic Information’ (VGDI), we attempt to lay the ground for full conceptual and applied spatio‐temporal integration. To illustrate that integrative approach of VGDI and its benefits, we describe the potential impact on the field of dynamic population distribution modeling. While traditional approaches in that domain rely on survey‐based data and statistics as well as static geographic information, the use of VGDI enables a dynamic setup. Foursquare venue and user check‐in data are presented for a test site in Lisbon, Portugal. Two core modules of spatio‐temporal population assessment are thereby addressed, namely time use profiling and target zone characterization, motivated by the potential integration in existing population dynamics frameworks such as the DynaPop model.  相似文献   

Analysis of the IR and sub-MM emission of four post-AGB stars     

Carsten Kömpe  Joachim Gürtler  Thomas Henning 《Astrophysics and Space Science》1995,224(1-2):353-356

The goal of this work is to derive the physical properties of dust envelopes around post-AGB stars by means of radiative transfer calculations. The model spectral energy distributions (SEDs) have been compared with observational data of the post-AGB stars IRAS 10215-5916, 16342-3814, 17150-3224, and 19500-1709 in the wavelength range from 0.4 to 1300µm. The match between our model SEDs and the observational data is very satisfactory. As a result, we have obtained estimates of the inner and outer radii, the density, the temperature, and the mass of the envelopes of the four objects.  相似文献   

Durchsichtigkeitsregistrierungen als ozeanographische Untersuchungsmethode     

Joachim Joseph 《Ocean Dynamics》1950,3(1-2):69-77

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Die Gliederung des Pliozäns im Mainzer Becken     

Joachim Bartz 《International Journal of Earth Sciences》1949,37(1):113-114

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Some remarks on making remote sensing-based mapping of elements at risk usable in international development cooperation     

Post  Joachim  Villagr&#;n  Juan Carlos de L&#;on  St-Pierre  Luc 《Natural Hazards》2016,81(1):189-201

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An easy approach to assess the susceptibility of a landslide by utilizing simple raster overlay methods: A case study on Huangtupo landslide (P.R. China)     

Christian Dumperth  Joachim Rohn  Alexander Fleer  Jin-Ge Wang  Wei Xiang  Karsten Zimmermann 《山地科学学报》2016,13(10):1701-1710

Semi qualitative index based methods using rankings and ratings are commonly used in susceptibility estimations over a wide area. However, generalized ranking and ratings are not applicable for one single landslide. This paper gives an easy and transferable approach to a susceptibility assessment of Huangtupo landslide (P.R. China), using raster addition without taking account for ranking and ratings. Slope, aspect, curvature, location and drainage buffer distance raster data sets have been obtained out of open source digital elevation models using ESRI’s ArcGIS. These conditioning factor raster data sets have been translated into raster data sets including simple yes or no criteria, referring to triggering or not. Subsequently they have been added by raster math to acquire a simple raster overlay map. After that this map is compared to initial displacement measurements, obtained by using a ground based synthetic aperture radar device. Acquired data is recalculated to a raster data set using the same spatial extent, to provide the possibility of comparison of the two raster data sets. The results reveal, that 76.35% of all measured movements occur in areas where raster cells include three or more conditioning factors, indicating that easy raster math operations can lead to satisfying results in local scale.  相似文献   

Erosion rates on subalpine paleosurfaces in the western Mediterranean by in-situ <Superscript>10</Superscript>Be concentrations in granites: implications for surface processes and long-term landscape evolution in Corsica (France)     

Joachim Kuhlemann  Klaas van der Borg  Paul D. Bons  Martin Danišík  Wolfgang Frisch 《International Journal of Earth Sciences》2008,97(3):549-564

A study of erosion rates by in-situ ¹⁰Be concentrations in granites of Miocene high-elevation paleosurfaces in Corsica indicates maximum erosion rates between 8 and 24 mm/kyear. The regional distribution of measured erosion rates indicates that the local climatic conditions, namely precipitation, the petrographic composition of granites, and the degree of brittle deformation govern erosion rates. Chemical erosion dominates even at elevations around 2,000 m in presently subalpine climate conditions. Field evidence indicates that erosion operates by continuous dissolution and/or disintegration to grains (grusification). The erosion rates are relatively high with respect to the preservation of inferred Early Miocene landscapes. We infer temporal burial in the Middle Miocene and significantly lower erosion rates in the Neogene until ∼3 Ma to explain the preservation of paleosurfaces, in line with fission track data. Valley incision rates that are a magnitude higher than erosion rates on summit surfaces result in relief enhancement and long-term isostatic surface uplift. On the other hand, widening and deepening of valleys by cyclic glaciation progressively destroys the summit surface relics.

Wolfgang FrischEmail:

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Citizens' perceptions of justice in international climate policy: an empirical analysis     

Joachim Schleich  Elisabeth Dütschke  Claudia Schwirplies  Andreas Ziegler 《Climate Policy》2016,16(1):50-67

Relying on a recent survey of more than 3400 participants from China, Germany, and the US, this article empirically analyses citizens' perceptions of key guiding principles for sharing mitigation costs across countries, justification of climate policy and trust in climate policy. Our findings suggest that the ranking of the main principles for burden-sharing is identical in China, Germany, and the US: accountability followed by capability, egalitarianism, and sovereignty. Thus, on a general level, citizens across these countries seem to have a common (normative) understanding of fairness. We therefore find no evidence that citizens' (stated) fairness preferences are detrimental to future burden-sharing agreements. In all three countries a majority of citizens considers international climate policy to be justified, but citizens' perceptions differ across specific items and countries. Finally, a substantial portion of citizens in all countries exhibit a lack of trust in international climate agreements.

Policy relevance

Disagreement over the distribution of mitigation costs across countries is blocking current negotiations about a new international climate change agreement to be adopted in 2015. At the heart of this disagreement are different perceptions of distributive justice among those involved in climate policy making. Our findings show that there is no difference in the ranking of fairness principles across citizens in China, Germany, and the US, suggesting that the common ground for crafting a future agreement is larger than expected. In particular, the accountability principle should weigh heavily when deciding on the burden-sharing. In addition, our findings suggest that in order to gain support among citizens, international climate policy may need to take measures to improve trust.  相似文献