AffectRoute – considering people’s affective responses to environments for enhancing route-planning services     

Haosheng Huang  Silvia Klettner  Manuela Schmidt  Georg Gartner  Sven Leitinger  Andreas Wagner 《International journal of geographical information science》2014,28(12):2456-2473

Humans perceive and evaluate environments affectively. Some places are experienced as unsafe, while some others as attractive and interesting. These affective responses to environments influence people’s daily behavior and decision-making in space, e.g., choosing which route to take, or which place to visit. In this article, we report on a methodology of using people’s affective responses to environments for enhancing computer-based route planning. More specifically, we explore a crowdsourcing approach to model and collect people’s affective responses to environments; an Affect-Space-Model and a mobile application are developed to facilitate this crowdsourcing approach; a routing algorithm (named AffectRoute) is then proposed to aggregate and integrate the collected data for automatic route planning. Evaluation with human participants shows that the routes generated by considering people’s affective responses to environments are significantly preferred over the conventional shortest ones, which are employed in car navigation systems and many online route planners. In conclusion, considering people’s affective responses to environments contributes to the improvement of automatic route planning. The proposed method can be integrated into existing route-planning services (e.g., location-based services) to provide users with more satisfying routing results.  相似文献   

Time-scale and state dependence of the carbon-cycle feedback to climate     

Matteo Willeit  Andrey Ganopolski  Daniela Dalmonech  Aideen M. Foley  Georg Feulner 《Climate Dynamics》2014,42(7-8):1699-1713

Climate and atmospheric CO₂ concentration are intimately coupled in the Earth system: CO₂ influences climate through the greenhouse effect, but climate also affects CO₂ through its impact on the amount of carbon stored on land and in the ocean. The change in atmospheric CO₂ as a response to a change in temperature ( $\varDelta CO_{2}/\varDelta T$ ) is a useful measure to quantify the feedback between the carbon cycle and climate. Using an ensemble of experiments with an Earth system model of intermediate complexity we show a pronounced time-scale dependence of $\varDelta CO_{2}/\varDelta T$ . A maximum is found on centennial scales with $\varDelta CO_{2}/\varDelta T$ values for the model ensemble in the range 5–12 ppm °C^?1, while lower values are found on shorter and longer time scales. These results are consistent with estimates derived from past observations. Up to centennial scales, the land carbon response to climate dominates the CO₂ signal in the atmosphere, while on longer time scales the ocean becomes important and eventually dominates on multi-millennial scales. In addition to the time-scale dependence, modeled $\varDelta CO_{2}/\varDelta T$ show a distinct dependence on the initial state of the system. In particular, on centennial time-scales, high $\varDelta CO_{2}/\varDelta T$ values are correlated with high initial land carbon content. A similar relation holds also for the CMIP5 models, although for $\varDelta CO_{2}/\varDelta T$ computed from a very different experimental setup. The emergence of common patterns like this could prove to usefully constrain the climate–carbon cycle feedback.  相似文献   

Microplastics in oceans     

Zarfl C  Fleet D  Fries E  Galgani F  Gerdts G  Hanke G  Matthies M 《Marine pollution bulletin》2011,62(8):1589-1591

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Ecological stability during the LGM and the mid-Holocene in the Alpine Steppes of Tibet?     

Georg Miehe  Sabine Miehe  Kerstin Bach  Jürgen Kluge  Karsten Wesche  Yang Yongping  Liu Jianquan 《Quaternary Research》2011,76(2):243-252

Arid and Alpine ecosystems are known for extreme environmental changes during the Late Quaternary. We hypothesize that the world's largest Alpine arid ecosystem however, the Alpine Steppes of the Tibetan highlands, remained ecologically stable during the LGM and the mid-Holocene. This hypothesis is tested by distributional range of plant species, plant life forms and rate of endemism. The set of character species has a precipitation gradient between 50 and 350 mm/a, testifying for resilience to precipitation changes. 83% of the species have a wider vertical range than 1000 m used as a proxy for resilience to temperature changes. 30% of the species are endemic with 10 endemic genera, including plate-shaped cushions as a unique plant life form. These findings are in line with palaeo-ecological proxies (δ¹⁸O, pollen) allowing the assumption that Alpine Steppes persisted during the LGM with 3 to 4 K lower summer temperatures.During the mid-Holocene, forests could have replaced Alpine Steppes in the upper catchments of the Huang He, Yangtze, Mekong, Salween and Yarlung Zhangbo, but not in the interior basins of the north-western highlands, because the basins were then flooded, suppressing forests and supporting the environmental stability of this arid Alpine grassland biome.  相似文献   

Silicon isotope fractionation during magmatic differentiation   总被引：3，自引：0，他引：3  

Paul S. Savage  R. Bastian Georg  Kevin W. Burton  Alex N. Halliday 《Geochimica et cosmochimica acta》2011,75(20):6124-6139

The Si isotopic composition of Earth’s mantle is thought to be homogeneous (δ³⁰Si = −0.29 ± 0.08‰, 2 s.d.) and not greatly affected by partial melting and recycling. Previous analyses of evolved igneous material indicate that such rocks are isotopically heavy relative to the mantle. To understand this variation, it is necessary to investigate the degree of Si isotopic fractionation that takes place during magmatic differentiation. Here we report Si isotopic compositions of lavas from Hekla volcano, Iceland, which has formed in a region devoid of old, geochemically diverse crust. We show that Si isotopic composition varies linearly as a function of silica content, with more differentiated rocks possessing heavier isotopic compositions. Data for samples from the Afar Rift Zone, as well as various igneous USGS standards are collinear with the Hekla trend, providing evidence of a fundamental relationship between magmatic differentiation and Si isotopes. The effect of fractionation has been tested by studying cumulates from the Skaergaard Complex, which show that olivine and pyroxene are isotopically light, and plagioclase heavy, relative to the Si isotopic composition of the Earth’s mantle. Therefore, Si isotopes can be utilised to model the competing effects of mafic and felsic mineral fractionation in evolving silicate liquids and cumulates.At an average SiO₂ content of ∼60 wt.%, the predicted δ³⁰Si value of the continental crust that should result from magmatic fractionation alone is −0.23 ± 0.05‰ (2 s.e.), barely heavier than the mantle. This is, at most, a maximum estimate, as this does not take into account weathered material whose formation drives the products toward lighter δ³⁰Si values. Mass balance calculations suggest that removal of continental crust of this composition from the upper mantle will not affect the Si isotopic composition of the mantle.  相似文献   

Calcite dissolution kinetics in the system CaCO₃-H₂O-CO₂ at high undersaturation     

Georg Kaufmann  Wolfgang Dreybrodt 《Geochimica et cosmochimica acta》2007,71(6):1398-1410

Dissolution rates of limestone covered by a water film open to a CO₂-containing atmosphere are controlled by the chemical composition of the CaCO₃-H₂O-CO₂ solution at the water-mineral interface. This composition is determined by the Ca²⁺-concentration at this boundary, conversion of CO₂ into H⁺ and in the solution, and by diffusional mass transport of the dissolved species from and towards the water-limestone interface. A system of coupled diffusion-reaction equations for Ca²⁺, , and CO₂ is derived. The Ca²⁺ flux rates at the surface of the mineral are defined by the PWP-empirical rate law. These flux rates by the rules of stoichiometry must be equal to the flux rates of CO₂ across the air-water interface. In the solution, CO₂ is converted into H⁺ and . At low water-film thickness this reaction becomes rate limiting. The time dependent diffusion-reaction equations are solved for free drift dissolution by a finite-difference scheme, to obtain the dissolution rate of calcite as a function of the average calcium concentration in the water film. Dissolution rates are obtained for high undersaturation. The results reveal two regimes of linear dissolution kinetics, which can be described by a rate law F = α_i(m_ic_eq − c), where c is the calcium concentration in the water film, c_eq the equilibrium concentration with respect to calcite. For index i = 0, a fast rate law, which here is reported for the first time, is found with α₀ = 3 × 10⁻⁶ m s⁻¹ and m₀ = 0.3. For c > m₀c_eq, a slow rate law is valid with α₁ = 3 × 10⁻⁷ m  s⁻¹ and m₁ = 1, which confirms earlier work. The numbers given above are valid for film thickness of several tenths of a millimetre and at 20 °C. These rates are proven experimentally, using a flat inclined limestone plate covered by a laminar flowing water film injected at an input point with known flow rate Q and calcium concentration. From the concentration measured after flow distance x the dissolution rates are determined. These experiments have been performed at a carbon-dioxide pressure of 0.00035 atm and also of 0.01 atm. The results are in good agreement to the theoretical predictions.  相似文献   

Simulations of VLBI observations of a geodetic satellite providing co-location in space     

James M. Anderson  Georg Beyerle  Susanne Glaser  Li Liu  Benjamin Männel  Tobias Nilsson  Robert Heinkelmann  Harald Schuh 《Journal of Geodesy》2018,92(9):1023-1046

We performed Monte Carlo simulations of very-long-baseline interferometry (VLBI) observations of Earth-orbiting satellites incorporating co-located space-geodetic instruments in order to study how well the VLBI frame and the spacecraft frame can be tied using such measurements. We simulated observations of spacecraft by VLBI observations, time-of-flight (TOF) measurements using a time-encoded signal in the spacecraft transmission, similar in concept to precise point positioning, and differential VLBI (D-VLBI) observations using angularly nearby quasar calibrators to compare their relative performance. We used the proposed European Geodetic Reference Antenna in Space (E-GRASP) mission as an initial test case for our software. We found that the standard VLBI technique is limited, in part, by the present lack of knowledge of the absolute offset of VLBI time to Coordinated Universal Time at the level of microseconds. TOF measurements are better able to overcome this problem and provide frame ties with uncertainties in translation and scale nearly a factor of three smaller than those yielded from VLBI measurements. If the absolute time offset issue can be resolved by external means, the VLBI results can be significantly improved and can come close to providing 1 mm accuracy in the frame tie parameters. D-VLBI observations with optimum performance assumptions provide roughly a factor of two higher uncertainties for the E-GRASP orbit. We additionally simulated how station and spacecraft position offsets affect the frame tie performance.  相似文献   

Annotated translation of “Die Wasserversorgung einiger Nordseebäder [The water supply of some North Sea spas]” by Alexander Herzberg (1901)     

Georg Houben 《Hydrogeology Journal》2018,26(6):1789-1799

The publication “The water supply of some North Sea spas” by Alexander Herzberg in 1901 is a cornerstone of coastal groundwater research. It was fundamental to the development of the Ghijben-Herzberg principle, which describes the hydrostatic equilibrium between fresh and saline groundwater. Due to its age and the language barrier, the paper is often cited but probably rarely read. Therefore, the original paper has been translated from German into English, accompanied by an introduction and notes explaining the historical context.  相似文献   

Celebrating 50 years of SWIMs (Salt Water Intrusion Meetings)     

Vincent E. A. Post  Gualbert Oude Essink  Adam Szymkiewicz  Mark Bakker  Georg Houben  Emilio Custodio  Clifford Voss 《Hydrogeology Journal》2018,26(6):1767-1770

The Salt Water Intrusion Meetings, or SWIMs, are a series of meetings that focus on seawater intrusion in coastal aquifers and other salinisation processes. 2018 marks the 50th year of the SWIM and the 25th biennial meeting. The SWIM proceedings record half a century of research progress on site characterisation, geophysical and geochemical techniques, variable-density flow, modelling, and water management. The SWIM is positioning itself to remain a viable platform for discussing the coastal aquifer management challenges of the next 50 years.  相似文献   

<Superscript>10</Superscript>Be surface exposure dating of the last deglaciation in the Aare Valley,Switzerland     

Lorenz Wüthrich  Ezequiel Garcia Morabito  Jana Zech  Mareike Trauerstein  Heinz Veit  Christian Gnägi  Silke Merchel  Andreas Scharf  Georg Rugel  Marcus Christl  Roland Zech 《Swiss Journal of Geoscience》2018,111(1-2):295-303

The combined Rhone and Aare Glaciers presumably reached their last glacial maximum (LGM) extent on the Swiss Plateau prior to 24 ka. Two well-preserved, less extensive moraine stades, the Gurten and Bern Stade, document the last deglaciation of the Aare Valley, yet age constraints are very scarce. In order to establish a more robust chronology for the glacial/deglacial history of the Aare Valley, we applied ¹⁰Be surface exposure dating on eleven boulders from the Gurten and Bern Stade. Several exposure ages are of Holocene age and likely document post-depositional processes, including boulder toppling and quarrying. The remaining exposure ages, however yield oldest ages of 20.7 ± 2.2 ka for the Gurten Stade and 19.0 ± 2.0 ka for the Bern Stade. Our results are in good agreement with published chronologies from other sites in the Alps.  相似文献