Assimilation of Historical Head Data to Estimate Spatial Distributions of Stream Bed and Aquifer Hydraulic Conductivity Fields

Management of water resources in alluvial aquifers relies mainly on understanding interactions between hydraulically connected streams and aquifers. Numerical models that simulate this interaction often are used as decision support tools in water resource management. However, the accuracy of numerical predictions relies heavily on the unknown system parameters (i.e. stream bed conductivity and aquifer hydraulic conductivity) which are spatially heterogeneous and difficult to measure directly. This paper employs an Ensemble Smoother to invert groundwater level measurements to jointly estimate spatially-varying streambed and alluvial aquifer hydraulic conductivity along a 35.6 km segment of the South Platte River in northeastern Colorado. The accuracy of the inversion procedure is evaluated using a synthetic experiment and historical groundwater level measurements, with the latter constituting the novelty of this study in the inversion and validation of high resolution fields of streambed and aquifer conductivities. Results show that the estimated streambed conductivity field and aquifer conductivity field produce an acceptable agreement between observed and simulated groundwater levels and stream flow rates. The estimated parameter fields are also used to simulate the spatially varying flow exchange between the alluvial aquifer and the stream, which exhibit high spatial variability along the river reach with a maximum average monthly aquifer gain of about 2.3 m3/day and a maximum average monthly aquifer loss of 2.8 m3/day, per unit area of streambed (m2). These results demonstrate that data assimilation inversion provides a reliable and computationally affordable tool to estimate the spatial variability of streambed and aquifer conductivities at high resolution in real-world systems

Evaluation of transforming growth factor and vascular endothelial growth factor polymorphisms in Taiwan Chinese patients with pterygium

[[abstract]]PURPOSE. Pterygium is an invasive and highly vascularized growth, thought to arise from activated and proliferating limbal epithelial stem cells. Epidemiologic studies have found the increase of active angiogenic and epithelial growth factors in pterygia, and implicated that these molecules could be involved directly or indirectly in the pathogenesis of pterygia as causative factors. The aim of this study was to investigate the association of polymorphisms of transforming growth factor (TGF) and vascular endothelial growth factor (VEGF) with pterygium. METHODS. A total of 133 pterygium patients and 105 volunteers without pterygium were enrolled in this study. Polymerase chain reaction based restriction fragment length polymorphism analysis was used to resolve the TGF-beta 1-509 and VEGF-460 genotypes. RESULTS. There was no significant difference in the allele frequency or genotype of TGF-beta 1-509 or VEGF-460 between total pterygium and the control group. No interaction between TGF-beta 1-509 and VEGF-460 was found either. CONCLUSIONS. These results indicate that TGF-beta 1-509 and VEGF-460 polymorphisms were not highly associated with the pathology of pterygium. However, it may still be worthwhile to continue to search for angiogenic gene polymorphisms in order to predict the development of pterygium

Effects of selective dilution on the magnetic properties of La_{0.7}Sr_{0.3}Mn_{1-x}M'_xO_3 (M' = Al, Ti)

The magnetic lattice of mixed-valence Mn ions in La$_{0.7}$Sr$_{0.3}$MnO$_{3}$ is selectively diluted by partial substitution of Al or Ti for Mn. The ferromagnetic transition temperature $T_\mathrm{c}$ and the saturation magnetization $M_\mathrm{s}$ both decrease with substitution. By presenting the data in terms of selective dilution, $T_\mathrm{c}$ in the low-doping region is found to follow the relation $T_\mathrm{c}=T_\mathrm{c0}(1-n_\mathrm{p})$, where $T_\mathrm{c0}$ refers to the undiluted system and $n_\mathrm{p}$ is the dilution concentration defined as $n_\mathrm{p}=x/0.7$ or $n_\mathrm{p}=x/0.3$ for $M^\prime=$ Al or Ti, respectively. The scaling behavior of $T_\mathrm{c}(n_\mathrm{p})$ can be analyzed in the framework of the molecular-field theory and still valid when Mn is substituted by both Al and Ti. The results are discussed with respect to the contributions from ferromagnetic double exchange and other possible antiferromagnetic superexchange interactions coexisting in the material.Comment: Revtex4, 4 pages, 4 figures, 2006 Halong Conference Repor

Careers in family business: New avenues for careers and family business research in the 21st century

The purpose of our special issue is to demonstrate how a careers perspective can contribute to the study of family businesses and bring to light how the family business context extends and challenges career theories and concepts. Inspired by the studies in our special issue and our review of previous research, we propose a conceptual model that leverages the concept of family embeddedness and intertwines it with career processes and outcomes. Building on the family embeddedness perspective, we propose several avenues for future research for family business and career scholars

Second-order discontinuous Galerkin flood model: comparison with industry-standard finite volume models

Finite volume (FV) numerical solvers of the two-dimensional shallow water equations are core to industry-standard flood models. The second-order Discontinuous Galerkin (DG) alternative is well-known to perform better than first- and second-order FV to capture sharp flow fronts and converge faster at coarser resolutions, but DG2 models typically rely on local slope limiting to selectively damp numerical oscillations in the vicinity of shock waves. Yet flood inundation events are smooth and gradually-varying, and shock waves play only a minor role in flood inundation modelling. Therefore, this paper investigates two DG2 variants - with and without local slope limiting - to identify the simplest and most efficient DG2 configuration suitable for flood inundation modelling. The predictive capabilities of the DG2 variants are analysed for a synthetic test case involving advancing and receding waves representative of flood-like flow. The DG2 variants are then benchmarked against industry-standard FV models over six UK Environment Agency scenarios. Results indicate that the DG2 variant without local slope limiting closely reproduces solutions of the commercial models at twice as coarse a spatial resolution, and removing the slope limiter can halve model runtime. Results also indicate that DG2 can capture more accurate hydrographs incorporating small-scale transients over long-range simulations, even when hydrographs are measured far away from the flooding source. Accompanying details of software and data accessibility are provided

Pengembangan Metode Bangkitan Dan Tarikan Perjalanan Berdasarkan Citra Quickbird

As a basic model, trip generation model aims to obtain the number of movement generated by each origin and the one attracted to each destination zone. Based on the movement, trip generation model is categorized into home-based trip generation and non home-originated/destinated trip attraction. Given that the different types of activities attract trips with different characteristics, it can be concluded that land use management determines the movement and activities. Remote sensing imagery has been extensively used in various research themes including land use management or land use and detailed land utility. As one of the remote sensing imageries, Quickbird imagery is advantageous with its high spatial resolution which is 0.61 cm. Therefore, it is interesting to apply the 0.61 cm spatial resolution to the trip generation model to estimate the number of trips at the trip generation. This aims is to minimize field activities which are high cost, extensive workers, and relatively time consuming