bluuebunny/crossref_metadata_2025_split huggingface dataset:
Temporal variations of atmospheric depositional fluxes of 7Be and 210Pb over 8 years (2006–2013) at Shanghai, China, and synthesis of global fallout data
Authors: Du Juan , Du Jinzhou , Baskaran Mark , Bi Qianqian , Huang Dekun , Jiang Yifei 
Published: March 2015

Abstract7Be and 210Pb, two atmospherically delivered radionuclides, have been broadly applied to study the processes including air mass transport, soil erosion, and particle cycling in aqueous systems. These studies require temporal variations of their depositional fluxes. In the present work, monthly atmospheric bulk depositional fluxes of 7Be and 210Pb were measured over 8 years (December 2005 to December 2013) at Shanghai, China. The bulk depositional fluxes of 7Be and 210Pb varied from 17.9 to 421 Bq m−2 month−1 and 6.8 to 82.1 Bq m−2 month−1, respectively. The volume‐weighted activities ranged from 0.20 to 8.06 Bq L−1 for 7Be and 0.05 to 3.40 Bq L−1 for 210Pb. There were strong seasonal variations in the depositional fluxes of these nuclides. The seasonal fraction of depositional fluxes was >30% of the total annual depositional fluxes of 210Pb in winter and 7Be in spring. The lowest depositional fluxes were found in summer for both radionuclides, with precipitation‐normalized enrichment factor (α) values of <1.0. The results from the synthesis of global fallout data indicate that there are latitudinal variations in the maximum depositional fluxes and volume‐weighted activities of 7Be, both values increase with latitude from the equator to the midlatitudes. The 210Pb depositional fluxes increase with the distance from the coast in inland regions (distance from the coast >50 km) and increase with the amount of precipitation in onshore region (distance from the coast ≤50 km). We also report that Shanghai, China, has the second highest bulk depositional fluxes of 210Pb in literature.
How well do CMIP5 climate simulations replicate historical trends and patterns of meteorological droughts?
Authors: Nasrollahi Nasrin , AghaKouchak Amir , Cheng Linyin , Damberg Lisa , Phillips Thomas J. , Miao Chiyuan , Hsu Kuolin , Sorooshian Soroosh 
Published: March 2015

AbstractAssessing the uncertainties and understanding the deficiencies of climate models are fundamental to developing adaptation strategies. The objective of this study is to understand how well Coupled Model Intercomparison‐Phase 5 (CMIP5) climate model simulations replicate ground‐based observations of continental drought areas and their trends. The CMIP5 multimodel ensemble encompasses the Climatic Research Unit (CRU) ground‐based observations of area under drought at all time steps. However, most model members overestimate the areas under extreme drought, particularly in the Southern Hemisphere (SH). Furthermore, the results show that the time series of observations and CMIP5 simulations of areas under drought exhibit more variability in the SH than in the Northern Hemisphere (NH). The trend analysis of areas under drought reveals that the observational data exhibit a significant positive trend at the significance level of 0.05 over all land areas. The observed trend is reproduced by about three‐fourths of the CMIP5 models when considering total land areas in drought. While models are generally consistent with observations at a global (or hemispheric) scale, most models do not agree with observed regional drying and wetting trends. Over many regions, at most 40% of the CMIP5 models are in agreement with the trends of CRU observations. The drying/wetting trends calculated using the 3 months Standardized Precipitation Index (SPI) values show better agreement with the corresponding CRU values than with the observed annual mean precipitation rates. Pixel‐scale evaluation of CMIP5 models indicates that no single model demonstrates an overall superior performance relative to the other models.
New ν‐type relative permeability curves for two‐phase flows through subsurface fractures
Authors: Watanabe Noriaki , Sakurai Keisuke , Ishibashi Takuya , Ohsaki Yutaka , Tamagawa Tetsuya , Yagi Masahiko , Tsuchiya Noriyoshi 
Published: March 2015

AbstractAppropriate relative permeability curves for two‐phase flows through subsurface fractures remain unclear. We have conducted decane‐water and nitrogen‐water two‐phase flow experiments and simulations on real variable‐aperture fractures in rocks under confining stress. Experiments have been conducted on fractures for different combinations of rock type (granite or limestone), wettability (contact angle of water: 0° or 90°), and intrinsic fracture permeability (10−11 m2 or 10−10 m2) using different combinations of shear displacement (0 or 1 mm) and effective confining stress (1 or 40 MPa). It has been demonstrated that nonwetting phase relative permeability depends on capillary pressure, except at either a higher contact angle or higher intrinsic permeability (i.e., bigger aperture), where no influence of capillarity is expected from the Young‐Laplace equation. In the absence of an influence of capillarity, relations between wetting and nonwetting phase relative permeabilities agree with that of the X‐type relative permeability curves. In order to determine the relative permeability curves under the influence of capillarity, the experimental results have been analyzed by two‐phase flow simulations of the aperture distributions of the fractures. It has been revealed that nonwetting phase relative permeability becomes zero, even at a small wetting phase saturation of approximately 0.3, while wetting phase relative permeability exhibits Corey‐type behavior, resulting in ν‐shaped relative permeability curves. Similar curves have been reported in the literature, but have not been demonstrated for real fractures. It has been revealed that the new ν‐type and traditional X‐type relative permeability curves are appropriate for describing two‐phase flows through subsurface fractures.
Calibrating remotely sensed river bathymetry in the absence of field measurements: Flow REsistance Equation‐Based Imaging of River Depths (FREEBIRD)
Authors: Legleiter Carl J. 
Published: March 2015

AbstractRemote sensing could enable high‐resolution mapping of long river segments, but realizing this potential will require new methods for inferring channel bathymetry from passive optical image data without using field measurements for calibration. As an alternative to regression‐based approaches, this study introduces a novel framework for Flow REsistance Equation‐Based Imaging of River Depths (FREEBIRD). This technique allows for depth retrieval in the absence of field data by linking a linear relation between an image‐derived quantity X and depth d to basic equations of open channel flow: continuity and flow resistance. One FREEBIRD algorithm takes as input an estimate of the channel aspect (width/depth) ratio A and a series of cross‐sections extracted from the image and returns the coefficients of the X versus d relation. A second algorithm calibrates this relation so as to match a known discharge Q. As an initial test of FREEBIRD, these procedures were applied to panchromatic satellite imagery and publicly available aerial photography of a clear‐flowing gravel‐bed river. Accuracy assessment based on independent field surveys indicated that depth retrieval performance was comparable to that achieved by direct, field‐based calibration methods. Sensitivity analyses suggested that FREEBIRD output was not heavily influenced by misspecification of A or Q, or by selection of other input parameters. By eliminating the need for simultaneous field data collection, these methods create new possibilities for large‐scale river monitoring and analysis of channel change, subject to the important caveat that the underlying relationship between X and d must be reasonably strong.
CO2 dissolution in the presence of background flow of deep saline aquifers
Authors: Emami‐Meybodi Hamid , Hassanzadeh Hassan , Ennis‐King Jonathan 
Published: March 2015

AbstractWe study the effect of background flow on the dissolution and transport of carbon dioxide (CO2) during geological storage in saline aquifers, and include the processes of diffusion, advection, and free convection. We develop a semianalytical model that captures the evolution of the dissolution in the absence of free convection. Using the semianalytical solution, we determine scaling relations for the steady rate of dissolution that follow either
or
depending on the value of Pe/R, where R represents the ratio of the extent of CO2 plume to the aquifer thickness and Pe is the Péclet number. Using direct numerical simulations, we provide detailed behavior of the convective mixing during the dissolution. We establish the criteria for forced and mixed (combined free and forced) convection in aquifers that is governed by the background flow. Accordingly, we provide the scaling relations
and
representing the forced and free convection asymptotes, respectively, where Ra is a Rayleigh number based on aquifer thickness. The results reveal that the background velocity can delay the onset of free convection and can alter the subsequent mixing. This phenomenon is more profound in the systems subject to strong background flows wherein horizontal component of the velocity field generated by background flow hinders the establishments of vertical component of the velocity field. Finally, by applying the proposed relations to several potential storage sites, we demonstrate the screening process in finding aquifers where the background flow exerts an important influence on the dissolution.
Global change and the groundwater management challenge
Authors: Gorelick Steven M. , Zheng Chunmiao 
Published: March 2015

AbstractWith rivers in critical regions already exploited to capacity throughout the world and groundwater overdraft as well as large‐scale contamination occurring in many areas, we have entered an era in which multiple simultaneous stresses will drive water management. Increasingly, groundwater resources are taking a more prominent role in providing freshwater supplies. We discuss the competing fresh groundwater needs for human consumption, food production, energy, and the environment, as well as physical hazards, and conflicts due to transboundary overexploitation. During the past 50 years, groundwater management modeling has focused on combining simulation with optimization methods to inspect important problems ranging from contaminant remediation to agricultural irrigation management. The compound challenges now faced by water planners require a new generation of aquifer management models that address the broad impacts of global change on aquifer storage and depletion trajectory management, land subsidence, groundwater‐dependent ecosystems, seawater intrusion, anthropogenic and geogenic contamination, supply vulnerability, and long‐term sustainability. The scope of research efforts is only beginning to address complex interactions using multiagent system models that are not readily formulated as optimization problems and that consider a suite of human behavioral responses.
The 1 April 2014 Pisagua tsunami: Observations and modeling
Authors: Catalán Patricio. A. , Aránguiz Rafael , González Gabriel , Tomita Takashi , Cienfuegos Rodrigo , González Juan , Shrivastava Mahesh N. , Kumagai Kentaro , Mokrani Cyril , Cortés Pablo , Gubler Alejandra 
Published: March 2015

AbstractOn 1 April 2014, an earthquake with moment magnitude Mw 8.2 occurred off the coast of northern Chile, generating a tsunami that prompted evacuation along the Chilean coast. Here tsunami characteristics are analyzed through a combination of field data and numerical modeling. Despite the earthquake magnitude, the tsunami was moderate, with a relatively uniform distribution of runup, which peaked at 4.6 m. This is explained by a concentrated maximal slip at intermediate depth on the megathrust, resulting in a rapid decay of tsunami energy. The tsunami temporal evolution varied, with locations showing sustained tsunami energy, while others showed increased tsunami energy at different times after the earthquake. These are the result of the interaction of long period standing oscillations and trapped edge wave activity controlled by inner shelf slopes. Understanding these processes is relevant for the region, which still posses a significant tsunamigenic potential.
Small‐scale waves on Jupiter: A reanalysis of New Horizons, Voyager, and Galileo data
Authors: Simon A. A. , Li L. , Reuter D. C. 
Published: March 2015

AbstractJupiter's equator‐encircling mesoscale waves were a distinguishing feature observed during the New Horizons Jupiter flyby. Measured velocities indicated eastward propagation, inconsistent with standing wave models developed after the Voyager encounters. We present revised New Horizons mesoscale wave velocities of 164 to 176 m/s, approximately 90 m/s higher than the tropospheric zonal winds on that date, while Voyager and Galileo mesoscale waves do not show any apparent motion. This is consistent with an eastward propagating inertia‐gravity or Kelvin wave, or a wave propagating with the wind at certain altitudes, given proper vertical wind shears. New Horizons high solar phase angle methane band observations show wave crest shadows or aerosol clearing, implying altitudes above the cloud deck for the observed features. New Horizons and Voyager data also indicate that wave trains have lifetimes exceeding two Jovian rotations.
Simulation of upscale error growth with a stochastic convection scheme
Authors: Selz Tobias , Craig George C. 
Published: March 2015

AbstractBy directly comparing the results of a recent convection‐permitting upscale error growth study with simulations on coarser grids, we assessed the ability of two different convection schemes to represent convective uncertainty and propagate it upscale. It is found that the widely used Tiedtke convection scheme shows significantly reduced upscale error growth and hence leads to an overconfidence of the model. In contrast it is found that the stochastic convection scheme of Plant and Craig is able to better reproduce the high‐resolution results. Evidence is presented that this improved uncertainty evolution can be related to the representation of (unpredictable) convective variability near the grid scale.
Spatiotemporal evolution of electron characteristics in the electron diffusion region of magnetic reconnection: Implications for acceleration and heating
Authors: Shuster J. R. , Chen L.‐J. , Hesse M. , Argall M. R. , Daughton W. , Torbert R. B. , Bessho N. 
Published: March 2015

AbstractBased on particle‐in‐cell simulations of collisionless magnetic reconnection, the spatiotemporal evolution of electron velocity distributions in the electron diffusion region (EDR) is reported to illustrate how electrons are accelerated and heated. Approximately when the reconnection rate maximizes, electron distributions in the vicinity of the X line exhibit triangular structures with discrete striations and a temperature (Te) twice that of the inflow region. Te increases as the meandering EDR populations mix with inflowing electrons. As the distance from the X line increases within the electron outflow jet, the discrete populations swirl into arcs and gyrotropize by the end of the jet with Te about 3 times that of the X line. Two dominant processes increase Te and produce the spatially and temporally evolving EDR distributions: (1) electric field acceleration preferential to electrons which meander in the EDR for longer times and (2) cyclotron turning by the magnetic field normal to the reconnection layer.
The global structure and time evolution of dayside magnetopause surface eigenmodes
Authors: Hartinger M. D. , Plaschke F. , Archer M. O. , Welling D. T. , Moldwin M. B. , Ridley A. 
Published: March 2015

AbstractTheoretical work and recent observations suggest that the dayside magnetopause may support its own eigenmode, consisting of propagating surface waves which reflect at the northern and southern ionospheres. These magnetopause surface eigenmodes (MSEs) are a potential source of magnetospheric ultralow‐frequency (ULF) waves with frequencies less than 2 mHz. Here we use the Space Weather Modeling Framework to study the magnetospheric response to impulsive solar wind dynamic pressure increases. Waves with 1.8 mHz frequency are excited whose global properties are largely consistent with theoretical predictions for MSE and cannot be explained by other known ULF wave modes. These simulation results lead to two key findings: (1) MSE can be sustained in realistic magnetic field geometries with nonzero flow shear and finite current layer thickness at the magnetopause and (2) MSE can seed the growth of tailward propagating surface waves via the Kelvin‐Helmholtz instability.
Latent‐Variable Modeling
Authors: Moustaki I. , Knott M. , Bartholomew D. J. 
Published: March 2015

AbstractThe article provides an overview of latent variable models including the classical factor analysis model, factor models for categorical manifest variables, structural equation models and more recent extensions for mixed (categorical and continuous) manifest and latent variables. Emphasis is given on model specification, estimation methods, goodness‐of‐fit test statistics, and factor scores.
Bootstrap and Jackknife, Overview
Authors: Martin Michael A. , Roberts Steven 
Published: March 2015

AbstractA quarter of a century ago, the advent of fast, cheap computing saw the emergence of computationally intensive methods that sought to exploit the data itself as a resource for information rather than relying on restrictive classical distributional assumptions that often failed to hold in practice. Methods such as the whimsically named jackknife and bootstrap have found wide use among practitioners in a variety of contexts. In this article, the basic uses of resampling techniques are described, with particular attention to bias and variance estimation and confidence interval construction. Implementation of these techniques in popular statistical software is also described.
Quality Control, Computing in
Authors: Noguera John , Breslaw Jon 
Published: March 2015

AbstractThe article provides a brief survey of important advances in quality control tools that are available to practitioners using current statistical quality software tools. The tools discussed include the use of the noncentral distribution function for power and sample size, exact statistics for small sample nonparametric tests and contingency tables, confidence intervals in measurement systems analysis, dealing with nonnormality and autocorrelation in statistical process control, and the use of genetic algorithms in the design and analysis of experiments.
Six Sigma Method
Authors: Does Ronald J.M.M. , Mast Jeroen De 
Published: March 2015

AbstractSix Sigma is built on principles and methods that have proven themselves over the twentieth century. It has incorporated the most effective approaches and integrated them into a full program. It offers a management structure for organizing continuous improvement of routine tasks, such as manufacturing, service delivery, accounting, nursing, sales, and other work that is done routinely. Further, it offers a method and tools for carrying out improvement projects effectively.
Surplus in Life and Pension Insurance
Authors: O'Brien Christopher David 
Published: March 2015

AbstractSurplus in life insurance is a key issue for participating business: actuarial control over the emergence and distribution of surplus is a major subject in the management of life insurance companies. Although we, here, concentrate on surplus in the context of participating life business, surplus is also relevant in any kind of fund in which long‐term liabilities may be valued on the basis of assumptions about the future. For example, shareholders have needs and expectations of surplus in nonparticipating life business, with premium rates and payouts being determined with a view to rewarding shareholders, who have provided capital and run risks. In pensions business, there are similar issues concerning the sources, size, analysis, and uses of surplus.
Pooling in Insurance
Authors: Aase Knut K. 
Published: March 2015

Abstract

In this article, we explore how pooling of economic risks is dealt with in insurance and reinsurance. Consider an average individual. Instead of facing risks in isolation, the individual may sort out a larger group of people with similar risks, and together work out a scheme how to share these. This should be done so that everyone comes out better than, or at least as good as, standing alone. In the article, I try to explain, by several examples, how pooling works in insurance. Pension insurance is our first example, where we point out how how pooling takes place along several different dimensions. A major concept is the
mutuality principle
, which we relate to both pension insurance and the theory of syndicates. We present some examples outside the field of insurance, with the same basic features, that of pooling individual risks. The last aspect of pooling that we discuss is best explained in the framework of information economics. This we do in a section about adverse selection.
Effect Size Measures
Authors: Kirk Roger E. 
Published: March 2015

AbstractA variety of measures of effect magnitude are described. Many of the measures can be classified as either measures of effect size (typically, standardized mean differences) or measures of strength of association. There also is a large group of statistics that do not fit into either category. Measures of effect magnitude are used for a variety of purposes: (i) to estimate the sample size required to achieve an acceptable power, (ii) to integrate the results of empirical research studies in meta‐analyses, (iii) to supplement the information provided by null‐hypothesis significance tests, and (iv) to determine whether research results are practically significant.
Trellis Graphics
Authors: Everitt Brian , Sarkar Deepayan 
Published: March 2015

Abstract
In trellis graphics one, two, or more variables are plotted and conditioned on different values or categories of a given variable (or variables). Component panels representing subsets of the data defined by levels of the conditioning variables are arranged in a single display in a manner that makes comparison easier. Many different types of plots lend themselves to this treatment, including scatterplots and three‐dimensional scatterplots. Trellis graphics help in understanding both the structure of the data and how well proposed models for the data actually fit.
Structural Equation Modeling: Software
Authors: Rigdon Edward E. 
Published: March 2015

Abstract

The first widely distributed special‐purpose software for estimating factor‐based structural equation models appeared almost 40 years ago. Today, researchers can choose from a variety of packages that differ markedly in terms of their intellectual heritage, interface, statistical sophistication, flexibility, integration with other statistical packages, and cost. Pioneers
LISREL
and
EQS
continue to offer their strengths. Mplus appears to be the package with the broadest set of out‐of‐the‐box ready capabilities, although a rapidly developing offering from Stata may pose future competition. Most recently, strong alternatives have appeared within the open‐source R environment, particularly including the increasingly sophisticated lavaan and the extremely flexible
OpenMx
. Despite numerous advances, there is still substantial room for improvement.