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61.
The development and widespread use of statistical learning models have brought the need for tools that help analysts diagnose, build, and refine those models. In this work, in particular, we focus on interpolation models, which spatially predict the value of a variable based on the values of its neighborhood. Investigating these results spatially or comparing them with other models at different levels of granularity is still a challenge for the analysts trying to understand and refine their models. To deal with that, we propose a visual analytics model-agnostic tool for facilitating the comparison and refinement of spatial models at different levels of granularity using interactive visualization techniques. The tool was built in collaboration with specialists who used it to diagnose and improve a spatial model for predicting residential real estate prices.  相似文献   
62.
In the Ribeira belt, southeastern Brazil, the Precambrian mylonitic fabric mainly formed during the Brasiliano/Pan-African orogeny (640–480 Ma) and was reactivated as fault zones in the Cretaceous and Cenozoic. The reactivation process led to the development of the System of Continental Rifts of southeastern Brazil, from the Paleogene to the Quaternary. We investigated the brittle reactivation of a mylonitic zone, which is part of a major mylonitic belt, Arcádia-Areal. We used geological and geomorphological mapping, resistivity survey, controlled source audiomagnetotelluric survey, and luminescence dating. Our results indicate that this shear zone was reactivated and formed a 15 km long and 2 km wide sedimentary-filled trough, the Rio Santana Graben. It is located on the northwest border of a major structure, the Guanabara Graben, in the State of Rio de Janeiro. The Rio Santana Graben forms an almost entirely fault-bounded, NE-elongated depression that was accommodated entirely within the Arcádia-Areal shear zone. The graben consists of two main depocenters separated by a relay ramp. The graben formed by means of multistage activity of several faults during at least two main periods. The first period formed silicified fault breccia and occurred during alkaline magmatism in the Paleogene. The second formed fault breccia and gouge in shallow conditions and occurred at least until the Quaternary. The NE-trending and NW-dipping Precambrian fabric was reactivated as dip-slip and strike-slip faults. These faults triggered clastic-sediment deposition at least 300 m thick. The upper part of the graben consists of Quaternary alluvial and colluvial sediment fill, which yielded maximum luminescence deposition ages from 49 to 13 ka in the center of the trough. An organic layer at the top of the Quaternary alluvial deposits yielded 14C ages at ~6000 years BP. The lower part of the graben may be composed of Paleogene to Neogene sedimentary deposits, which occur in other basins of the System of Continental Rifts of southeastern Brazil. We conclude that the Rio Santana Graben is an example of the direct control of a preexisting continental-scale rheological boundary on the geometry and location of fault systems and sediment deposition. Quaternary fault reactivation of the preexisting fabrics represents only the latest movement of a major structure.  相似文献   
63.
The 10-mile Slide is contained within an ancient earthflow located in British Columbia, Canada. The landslide has been moving slowly for over 40 years, requiring regular maintenance work along where a highway and a railway track cross the sliding mass. Since 2013, the landslide has shown signs of retrogression. Monitoring prisms were installed on a retaining wall immediately downslope from the railway alignment to monitor the evolution of the retrogression. As of September 2016, cumulative displacements in the horizontal direction approached 4.5 m in the central section of the railway retaining wall. After an initial phase of acceleration, horizontal velocities showed a steadier trend between 3 and 9 mm/day, which was then followed by a second acceleration phase. This paper presents an analysis of the characteristics of the surface displacement vectors measured at the monitoring prisms. Critical insight on the behavior and kinematics of the 10-mile Slide retrogression was gained. An advanced analysis of the trends of inverse velocity plots was also performed to assess the potential for a slope collapse at the 10-mile Slide and to obtain further knowledge on the nature of the sliding surface.  相似文献   
64.
65.
The term sustainable pumping rate (SPR) is defined as the maximum pumping rate that can be maintained indefinitely without mining an aquifer, and is different from the concept of safe yield (SY), which takes into account also aspects related to the much wider concept of sustainability. The assessment of the SPR for the case study of Petrignano d'Assisi, an alluvial aquifer located in Central Italy, shows the need for a reliable estimate of the global water budget of the aquifer, particularly of the recharge under undisturbed conditions; however, the latter is not sufficient, because the SPR is affected also by the geometry of the aquifer, the hydraulic conductivity pattern, the variation of recharge/discharge ratio induced by the abstractions, and so on. All these aspects are analyzed by means of a numerical flow model calibrated both under undisturbed conditions (1974) and under exploitation conditions (1998 to 2004). The steady-state modeling results show that the relation between recharge and abstractions both at local and global scale is a key point in order to estimate a long-term SPR. Moreover, as it could be necessary to overexploit the aquifer for short periods, e.g., during drought episodes, the estimate of SPR must be performed also in transient conditions, in order to take into account the characteristic time of depletion and the successive recovery.  相似文献   
66.
A composite sample of NIR-selected galaxies having extended multicolor coverage has been used to probe the cosmological evolution of the blue luminosity function and of the stellar mass function. The bright fraction of the sample has spectroscopic redshifts, and the remaining fraction well-calibrated photometric redshifts. The resulting blue luminosity function shows an increasing brightening with redshift respect to the local luminosity function. Hierarchical CDM models predictions are in agreement only at low and intermediate redshifts but fail to reproduce the observed brightening at high redshifts (z ∼ 2–3). This brightening marks the epoch where starburst activity triggered by galaxy interactions could be an important physical mechanism for the galaxy evolution. At the same time the NIR galaxy sample has been used to trace the evolution of the cosmological stellar mass density up to ∼3. A clear decrease of the average mass density is apparent with a fraction ∼15% of the local value at z ∼ 3. UV bright star-forming galaxies are substancial contributors to the evolution of the stellar mass density. Although these results are globally consistent with Λ–CDM scenarios, they tend to underestimate the mass density produced by more massive galaxies present at z > 2.  相似文献   
67.
In Mediterranean coastal catchments, water management for preservation of pine forests and other natural areas faces particular challenges. Limited rainfall, water consumption by vegetation as well as subsidence, drainage and salt water intrusion all play an important role. Traditionally forest and water management are carried out independent of one another and do not consider water budget calculations. We show with this study that is very important to have quantitative information of all the components of the water budget as well as the size of the fresh water lenses in the aquifer to be able to integrate the water- and forest management. We use an integrated hydrologic-ecologic methodology based on easily attainable data to assess the monthly water budget of a coastal catchment, Marina Romea (Ravenna, Italy). We present detailed monthly water table records, rainfall data, drainage data, tree density and tree perimeter and use published sap flow measurements of single pine trees (Pinus Pinea) to quantify the actual transpiration of single pine trees in different periods of the year. Transpiration amounts to 10–30 l per day per tree. These values are confirmed by independent estimates of tree transpiration based on our water budget calculations: 9–34 l/tree/day. Because typically there are so many trees in planted pine forests, the total transpiration rates over the whole watershed take up a large percentage (up to 200 %) of the precipitation. In Marina Romea, four monitoring periods out of twelve, the tree transpiration is larger than precipitation. In nine monitoring periods, drainage in the watershed is larger than precipitation or tree water transpiration. The measurements and calculations show that not much freshwater is left to recharge the fresh water lens underneath Marina Romea. Monthly monitoring of groundwater table elevation and salinity in the pine forest of Marina Romea from March 2007 to February 2008 shows that the groundwater table strongly fluctuates and groundwater salinity is constantly very high (up to 17.7 g/l). Analytical calculations based on the Ghyben Herzberg Dupuit principle suggest that even a small continuous annual recharge of 15 mm could form a 2-m deep freshwater lens in the unconfined aquifer. This freshwater lens is not present in the study area and this is due to the fact that tree water transpiration and drainage take out most of the fresh water coming into the watershed. In catchments like Marina Romea, water consumption by the (natural) vegetation and seasonal differences as well as the fact that fresh water lenses are limited in salty surroundings should be taken into account in water and forest management.  相似文献   
68.
The pn-CCD cameras at the focal plane of the eROSITA space observatory will be the first X-ray (0.2?C12?keV) detector to operate in a L-2 orbit. Therefore, no direct information of instrumental non X-ray background (NXB) is available to make predictions for eROSITA. Since, in general, the instrumental NXB experienced in orbit has a major impact on the overall sensitivity of the cameras, we investigated and modeled the L-2 radiation environment and its interaction with the eROSITA mass distribution and cameras, in order to quantify the expected pn-CCD NXB level. We obtain an average value of NXB ??25% lower than that observed by the pn-CCDs on-board the XMM-Newton satellite, which is placed in a Highly Elliptical Orbit (HEO). We discuss this result in light of the differences between the L-2 and HEO space environments.  相似文献   
69.
The Neoproterozoic carbonate sequence on the southeastern border of the Amazon Craton is divided into three lithostratigraphic units: a basal cap dolomite, an intermediate limestone, limestone-mudstone unit, and an upper dolarenite-dolorudite unit. Sections of the cap-carbonate were measured from the inner shelf to the outer shelf. Carbon isotope ratios (relative to PDB) vary between − 10.5 and − 1.7‰ in cap dolomite, and between − 5.4 and + 0.1‰ in laminated limestone and mud-limestone. Limestones and mud-limestones exhibit 87Sr/86Sr ratios ranging from 0.70740 to 0.70780. A comparative isotope stratigraphy between the inner-shelf and the middle-shelf basin shows differences in carbon isotope ratios: The cap dolomite and limestones have lower δ13C ratios on the border of the basin (inner shelf) than in the middle shelf of the basin. These lower values can be related to shallower environmental conditions and to a stronger influence of the continental border. The 87Sr/86Sr ratios are the same in both areas, and are consistent with seawater composition at around 600 Ma.  相似文献   
70.
We describe the development and preliminary application of the inverse Regional Ocean Modeling System (ROMS), a four dimensional variational (4DVAR) data assimilation system for high-resolution basin-wide and coastal oceanic flows. Inverse ROMS makes use of the recently developed perturbation tangent linear (TL), representer tangent linear (RP) and adjoint (AD) models to implement an indirect representer-based generalized inverse modeling system. This modeling framework is modular. The TL, RP and AD models are used as stand-alone sub-models within the Inverse Ocean Modeling (IOM) system described in [Chua, B.S., Bennett, A.F., 2001. An inverse ocean modeling system. Ocean Modell. 3, 137–165.]. The system allows the assimilation of a wide range of observation types and uses an iterative algorithm to solve nonlinear assimilation problems. The assimilation is performed either under the perfect model assumption (strong constraint) or by also allowing for errors in the model dynamics (weak constraints). For the weak constraint case the TL and RP models are modified to include additional forcing terms on the right hand side of the model equations. These terms are needed to account for errors in the model dynamics.Inverse ROMS is tested in a realistic 3D baroclinic upwelling system with complex bottom topography, characterized by strong mesoscale eddy variability. We assimilate synthetic data for upper ocean (0–450 m) temperatures and currents over a period of 10 days using both a high resolution and a spatially and temporally aliased sampling array. During the assimilation period the flow field undergoes substantial changes from the initial state. This allows the inverse solution to extract the dynamically active information from the synthetic observations and improve the trajectory of the model state beyond the assimilation window. Both the strong and weak constraint assimilation experiments show forecast skill greater than persistence and climatology during the 10–20 days after the last observation is assimilated.Further investigation in the functional form of the model error covariance and in the use of the representer tangent linear model may lead to improvement in the forecast skill.  相似文献   
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