bluuebunny/crossref_metadata_2025_split huggingface dataset:
Preschoolers’ different ways of structuring part-part-whole relations with finger patterns when solving an arithmetic task
Authors: Kullberg Angelika , Björklund Camilla 
Published: December 2019

AbstractIn this paper we report on findings from a study of 5-to-6-year-old children’s ways of structuring part-part-whole relations using finger patterns. We focused our analysis on data from interviews with 28 children who during their last year of preschool learned to enact a structural approach. We used this data set to analyze their different ways of structuring a task with one part unknown, and what constitutes the ability to structure the task in a conceptually powerful way. The way children structure number relations was interpreted as being related to how they experience the task at hand. We identified some ways of structuring as being more powerful for future learning, particularly those that facilitate the child in experiencing parts and the whole simultaneously. We suggest that there are three aspects that children need to discern in order to structure the task successfully in both the short and the long term: what constitutes the whole, the parts within the whole, and finger patterns as a representation of the cardinality of a set. The pedagogical implications are that attention to children’s ways of experiencing the number relations in arithmetic tasks gives clues to why some children develop powerful strategies, and how to support children in their learning to solve arithmetic tasks.
Chris Cannings: A Life in Games
Authors: Bishop D. Timothy , Broom Mark , Southwell Richard 
Published: December 2019

AbstractChris Cannings was one of the pioneers of evolutionary game theory. His early work was inspired by the formulations of John Maynard Smith, Geoff Parker and Geoff Price; Chris recognized the need for a strong mathematical foundation both to validate stated results and to give a basis for extensions of the models. He was responsible for fundamental results on matrix games, as well as much of the theory of the important war of attrition game, patterns of evolutionarily stable strategies, multiplayer games and games on networks. In this paper we describe his work, key insights and their influence on research by others in this increasingly important field. Chris made substantial contributions to other areas such as population genetics and segregation analysis, but it was to games that he always returned. This review is written by three of his students from different stages of his career.
Delay Performance of a Two-User Broadcast Channel with Security Constraints
Authors: Arvanitaki Antonia , Pappas Nikolaos , Mohapatra Parthajit , Carlsson Niklas 
Published: December 2019

AbstractIn this paper, we consider the two-user broadcast channel with security constraints. We assume that a source broadcasts packets to two receivers, and that one of them has secrecy constraints, i.e., its packets need to be kept secret from the other receiver. The receiver with secrecy constraint has full-duplex capability, allowing it to transmit a jamming signal to increase its secrecy. We derive the average delay per packet and provide simulations and numerical results, where we compare different performance metrics for the cases when both receivers treat interference as noise, when the legitimate receiver performs successive decoding, and when the eavesdropper performs successive decoding. The results show that successive decoding provides better average packet delay for the legitimate user. Furthermore, we define a new metric that characterizes the reduction on the success probability for the legitimate user that is caused by the secrecy constraint. The results show that secrecy poses a significant amount of packet delay for the legitimate receiver when either receiver performs successive decoding. We also formulate an optimization problem, wherein the throughput of the eavesdropper is maximized under delay and secrecy rate constraints at the legitimate receiver. We provide numerical results for the optimization problem, where we show the trade-off between the transmission power for the jamming and the throughput of the non-legitimate receiver. The results provide insights into how channel ordering and encoding differences can be exploited to improve performance under different interference conditions.
A systematic review and meta‐analysis of the association of neighborhood ethnic‐racial concentrations and adolescent behaviour problems in the U.S.
Authors: White Rebecca M.B. , Pasco Michelle C. , Korous Kevin M. , Causadias José M. 
Published: December 2019

ABSTRACTIntroductionEvidence suggesting a link between neighborhood ethnic‐racial concentrations and adolescent behaviour problems in the U.S. is mixed, with some studies documenting negative and others positive associations. This work raises important questions about promotingandinhibiting effects of neighborhood environments characterized by high concentrations of ethnic‐racial minority groups, including Asian Americans, Blacks or African Americans, and Latinos. We conducted a meta‐analysis to examine 1) the magnitude, direction, and variability of the association between neighborhood ethnic‐racial concentrations and adolescent behaviour problems, and 2) whether these associations varied by putative moderators.MethodsWe conducted a systematic search in PsycINFO, Web of Science, and PubMed as well as searching reference lists and relying on expert knowledge (285 initial records). We coded the records for theoretical and design elements.ResultsWe included 40 effect sizes from 17 records (24% unpublished) withN = 11,858. The average association between neighborhood ethnic‐racial concentrations and adolescent behaviour problems was not significantly different from zero (r = −0.001, 95% CI ‐0.048, 0.046,p = .964,τ2=0.006); there was a large percentage of systematic heterogeneity (I2 = 77.1%), which was not explained by putative moderators.ConclusionsThere is substantial unexplained systematic heterogeneity in the association between neighborhood ethnic‐racial concentrations and adolescents’ behaviour problems. There is heavy reliance on a small number of parent datasets in research on this topic, alongside critical reporting omissions. We offer recommendations to guide future work, in hopes of supporting culturally and developmentally informed policies and programs capable of addressing residential segregation.
Across‐Fault Velocity Gradients and Slip Behavior of the San Andreas Fault Near Parkfield
Authors: Piana Agostinetti N. , Giacomuzzi G. , Chiarabba C. 
Published: December 2019

AbstractA long‐lasting question in earthquake physics is why slip on faults occurs as creep or dynamic rupture. We compute passive measurements of the seismic P wave velocity gradient across the San Andreas Fault near Parkfield, where this transition of slip mode occurs at a scale of a few kilometers. Unbiased measurements are obtained through the application of a new Bayesian local earthquake tomographic code that avoids the imposition of any user‐defined, initial velocity‐contrast across the fault, or any damping scheme that may cause biased amplitude in retrieved seismic velocities. We observe that across‐fault velocity gradients correlate with the slip behavior of the fault. The P wave velocity contrast decays from 20% in the fault section that experience dynamic rupture to 4% in the creeping section, suggesting that rapid change of material properties and attitude to sustain supra‐hydrostatic fluid pressure are conditions for development of dynamic rupture. Low Vp and high Vp/Vs suggest that fault rheology at shallow depth is conversely controlled by low frictional strength material.
Quantifying the Effects of Nondiffuse Noise on Ballistic and Coda Wave Amplitude From Variances of Seismic Noise Interferometry in Southern California
Authors: Liu Xin , Beroza Gregory C. 
Published: December 2019

AbstractWe develop a new approach based on the variance of noise cross‐correlation to characterize the noise source and wave propagation under the influence of a nondiffuse noise field. Based on the standard errors for the Fourier spectra of stacked noise cross‐correlation and the assumption of a diffuse field, we derive an analytical expression for the variance of every time point in the stacked cross‐correlation and validate the theory using synthetic diffuse noise data. The ambient seismic noise field in Southern California is, however, not fully diffuse. The observed correlated neighboring frequencies in the noise data—a definitive character of the nondiffuse field, map into the noise cross‐correlation, biasing its variances from theoretical predictions under fully diffuse field assumption. For the secondary ocean microseism, we find strong positive correlation between the correlated neighboring frequencies and the deviations from diffuse field theory‐predicted variances. The ballistic arrivals on average contain more significant bias than the coda segments of the noise cross‐correlation, which agrees with previous time‐lapse monitoring studies based on ambient seismic noise. In addition, the station pairs having significant bias between actual and diffuse field theory‐predicted variances are aligned with the strongest source direction and exhibit significant beamforming source fluctuation.
Characterizing the Influence of Fracture Density on Network Scale Transport
Authors: Sherman Thomas , Hyman Jeffrey , Dentz Marco , Bolster Diogo 
Published: December 2019

AbstractThe topology of natural fracture networks is inherently linked to the structure of the fluid velocity field and transport therein. Here we study the impact of network density on flow and transport behaviors. We stochastically generate fracture networks of varying density and simulate flow and transport with a discrete fracture network model, which fully resolves network topology at the fracture scale. We study conservative solute trajectories with Lagrangian particle tracking and find that as fracture density decreases, solute channelization to large local fractures increases, thereby reducing plume spreading. Furthermore, in sparse networks mean particle travel distance increases and local network features, such as velocity zones where flow is counter to the primary pressure gradient, become increasingly important for transport. As the network density increases, network statistics homogenize and such local features have a reduced impact. We quantify local topological influence on transport behavior with an effective tortuosity parameter, which measures the ratio of total advective distance to linear distance at the fracture scale; large tortuosity values are correlated to slow‐velocity regions. These large tortuosity, slow‐velocity regions delay downstream transport and enhance tailing on particle breakthrough curves. Finally, we predict transport with an upscaled, Bernoulli spatial Markov random walk model and parameterize local topological influences with a novel tortuosity parameter. Bernoulli model predictions improve when sampling from a tortuosity distribution, as opposed to a fixed value as has previously been done, suggesting that local network topological features must be carefully considered in upscaled modeling efforts of fracture network systems.
Diagnostic Evaluation of Large‐Domain Hydrologic Models Calibrated Across the Contiguous United States
Authors: Rakovec Oldrich , Mizukami Naoki , Kumar Rohini , Newman Andrew J. , Thober Stephan , Wood Andrew W. , Clark Martyn P. , Samaniego Luis 
Published: December 2019

AbstractThis study presents diagnostic evaluation of two large‐domain hydrologic models: the mesoscale Hydrologic Model (mHM) and the Variable Infiltration Capacity (VIC) over the contiguous United States (CONUS). These models have been calibrated using the Multiscale Parameter Regionalization scheme in a joint, multibasin approach using 492 medium‐sized basins across the CONUS yielding spatially distributed model parameter sets. The mHM simulations are used as a performance benchmark to examine performance deficiencies in the VIC model. We find that after calibration to streamflow, VIC generally overestimates the magnitude and temporal variability of evapotranspiration (ET) as compared to mHM as well as the FLUXNET observation‐based ET product, resulting in underestimation of the mean and variability of runoff. We perform a controlled calibration experiment to investigate the effect of varying number of transfer function parameters in mHM and to enable a fair comparison between both models (14 and 48 for mHM vs. 14 for VIC). Results of this experiment show similar behavior of mHM with 14 and 48 parameters. Furthermore, we diagnose the internal functioning of the VIC model by looking at the relationship of the evaporative fraction versus the degree of soil saturation and compare it with that of the mHM model, which has a different model structure, a prescribed nonlinear relationship between these variables and exhibits better model skill than VIC. Despite these limitations, the VIC‐based CONUS‐wide calibration constrained against streamflow exhibits better ET skill as compared to two preexisting independent VIC studies.
Resistorless Realization of First‐Order Current Mode Universal Filter
Authors: Chaturvedi B. , Mohan J. , Jitender  , Kumar A. 
Published: December 2019

AbstractThis paper proposes a first‐order current mode universal filter employing single active building block, namely differential difference dual‐X second generation current conveyor. The proposed filter is designed to provide multiple filter responses simultaneously, namely low‐pass, high‐pass, and all‐pass on applying a current signal at its input terminal. The proposed work also enjoys the presence of metal oxide semiconductor transistors working as tunable resistors. Some of the key features of the proposed filter are as follows: use of single passive element (a grounded capacitor), ease of cascadability as all the outputs are available at highimpedance ports, low active and passive sensitivities, significantly high frequency of operation (3 MHz), low total harmonic distortion of output current (1.28%), low output current noise (10 pA/√Hz), and low power dissipation (2 mW). A detailed study of device nonidealities is also presented to show the satisfactory performance of the proposed structure under all practical considerations. PSPICE simulations effectively demonstrate the good performance of the proposed filter.
Forced Return Flow Deep in the Subduction Channel, Syros, Greece
Authors: Ring Uwe , Pantazides Hermes , Glodny Johannes , Skelton Alasdair 
Published: December 2019

AbstractWe present the results of a detailed structural study in the Cycladic Blueschist Unit at Fabrika on Syros Island, Greece, and discuss their significance for tectonic processes at the subduction interface. Some samples record top‐to‐the‐west shear reflecting prograde (burial), peak high‐pressure (HP) and initial decompression (exhumation) conditions. Other nearby samples record top‐to‐the‐east shear during HP metamorphism and exhumation. Some rocks re‐equilibrated at greenschist‐facies conditions and record top‐to‐the‐west shear. Greenschist‐facies top‐to‐the‐west shear is also found at the base of non‐HP upper units above the Fabrika HP sequence. We interpret the HP structures to reflect forced return flow and incipient formation of an extrusion wedge in the subduction channel. The HP top‐to‐the‐west structures resulted from thrusting along the base of the wedge and started to form during burial before the rocks reached their deepest point. The HP top‐to‐the‐east structures reflect deformation near the top of the developing extrusion wedge. After considerable exhumation during ongoing subduction, out‐of‐sequence, top‐to‐the‐west thrusts emplaced the non‐HP upper units above the exhuming extrusion wedge ~10 Myr after the wedge initially formed. Our work suggests that the HP rocks were considerably exhumed during sustained lithospheric shortening in the subduction channel by forced return flow. Because return flow is controlled by the velocity of the subducting slab, it may explain why HP rocks can be exhumed at subduction rates. On the regional scale we find that four distinct HP belts were sequentially accreted and exhumed between ~50 and 20 Ma suggesting continuous subduction‐channel return flow in the Hellenic subduction zone.
Snow Depth Patterns in a High Mountain Andean Catchment from Satellite Optical Tristereoscopic Remote Sensing
Authors: Shaw Thomas E. , Gascoin Simon , Mendoza Pablo A. , Pellicciotti Francesca , McPhee James 
Published: December 2019

AbstractObtaining detailed information about high mountain snowpacks is often limited by insufficient ground‐based observations and uncertainty in the (re)distribution of solid precipitation. We utilize high‐resolution optical images from Pléiades satellites to generate a snow depth map, at a spatial resolution of 4 m, for a high mountain catchment of central Chile. Results are negatively biased (median difference of −0.22 m) when compared against observations from a terrestrial Light Detection And Ranging scan, though replicate general snow depth variability well. Additionally, the Pléiades dataset is subject to data gaps (17% of total pixels), negative values for shallow snow (12%), and noise on slopes >40–50° (2%). We correct and filter the Pléiades snow depths using surface classification techniques of snow‐free areas and a random forest model for data gap filling. Snow depths (with an estimated error of ~0.36 m) average 1.66 m and relate well to topographical parameters such as elevation and northness in a similar way to previous studies. However, estimations of snow depth based upon topography (TOPO) or physically based modeling (DBSM) cannot resolve localized processes (i.e., avalanching or wind scouring) that are detected by Pléiades, even when forced with locally calibrated data. Comparing these alternative model approaches to corrected Pléiades snow depths reveals total snow volume differences between −28% (DBSM) and +54% (TOPO) for the catchment and large differences across most elevation bands. Pléiades represents an important contribution to understanding snow accumulation at sparsely monitored catchments, though ideally requires a careful systematic validation procedure to identify catchment‐scale biases and errors in the snow depth derivation.
A Computationally Efficient and Physically Based Approach for Urban Flood Modeling Using a Flexible Spatiotemporal Structure
Authors: Saksena Siddharth , Dey Sayan , Merwade Venkatesh , Singhofen Peter J. 
Published: December 2019

AbstractRecent unprecedented events have highlighted that the existing approach to managing flood risk is inadequate for complex urban systems because of its overreliance on simplistic methods at coarse‐resolution large scales, lack of model physicality using loose hydrologic‐hydraulic coupling, and absence of urban water infrastructure at large scales. Distributed models are a potential alternative as they can capture the complex nature of these events through simultaneous tracking of hydrologic and hydrodynamic processes. However, their application to large‐scale flood mapping and forecasting remains challenging without compromising on spatiotemporal resolution, spatial scale, model accuracy, and local‐scale hydrodynamics. Therefore, it is essential to develop techniques that can address these issues in urban systems while maximizing computational efficiency and maintaining accuracy at large scales. This study presents a physically based but computationally efficient approach for large‐scale (area > 103 km2) flood modeling of extreme events using a distributed model called Interconnected Channel and Pond Routing. The performance of the proposed approach is compared with a hyperresolution‐fixed‐mesh model at 60‐m resolution. Application of the proposed approach reduces the number of computational elements by 80% and the simulation time for Hurricane Harvey by approximately 4.5 times when compared to the fixed‐resolution model. The results show that the proposed approach can simulate the flood stages and depths across multiple gages with a high accuracy (R2 > 0.8). Comparison with Federal Emergency Management Agency building damage assessment data shows a correlation greater than 95% in predicting spatially distributed flooded locations. Finally, the proposed approach can estimate flood stages directly from rainfall for ungaged streams.
Evaluating the Sensitivity of Residential Water Demand Estimation to Model Specification and Instrument Choices
Authors: Puri Roshan , Maas Alexander 
Published: December 2019

AbstractThere is a substantial body of work that estimates residential water demand as a function of price, household characteristics, and weather. While most results suggest demand is inelastic, researchers have found qualitatively different estimates of price elasticity—both elastic (>1) and inelastic (<1). Inconsistency in the choice of the price signal, its instruments, and appropriate weather variables across studies makes it difficult to determine if the differences in elasticity estimates are real—due to location characteristics—or an artifice of model specification. Predicting accurate demand responses to price changes enables water utilities to stabilize and anticipate future revenue while meeting conservation goals. However, specifying residential water demand with the appropriate model (under block rate structure) is challenging for three reasons: (1) uncertainty around the appropriate price signal, (2) a lack of theoretical motivation for determining which (and how) weather variables affect demand, and (3) simultaneity issues in estimation require the use of instruments, which vary across studies. Therefore, to elucidate the effects of model choices on elasticity, we use a single location and systematically vary the specification of price, instruments, and weather variables across a suite of models. We reaffirm past results that households respond to the average price. We find reasonably stable and robust estimates of price elasticity across different weather and price instrument specification—with some notable exceptions—implying that low‐cost information like average temperature is sufficient to accurately reflect the data‐generating process, reducing costs and allowing for a parsimonious model.