bluuebunny/crossref_metadata_2025_split huggingface dataset:
Multi‐fidelity surrogate reduced‐order modeling of steady flow estimation
Authors: Wang Xu , Kou Jiaqing , Zhang Weiwei 
Published: May 2020

SummaryA multi‐fidelity reduced‐order model (ROM), which incorporates low‐fidelity data to improve the prediction of high‐fidelity results, is proposed for the reconstruction of steady flow field at different conditions. The spatial basis functions of low‐fidelity and high‐fidelity data, which are generated for all training sets are extracted separately by proper orthogonal decomposition. Then a surrogate model is used to construct mappings between the mode coefficients obtained from low‐fidelity and the high‐fidelity data. In the online stage, both the low‐fidelity flow at the predicted state and the surrogate model are needed to predict the mode coefficients of the high‐fidelity flow, and the high‐fidelity flow field is subsequently reconstructed. This method differs from existing surrogate‐based reduced‐order modeling method because it allows the use of partial physical information for flow estimation, which is coming from the low‐fidelity data instead of adopting a black‐box mapping between system state and the projection coefficients. Numerical studies are presented for a lid‐driven cavity problem and transonic flow past a NACA0012 airfoil. Two low‐fidelity models, with either a coarse mesh or a lower numerical order, are considered respectively. Results show that the proposed multi‐fidelity ROM predicts the flow field accurately and outperforms the traditional methods in both interpolated and extrapolated conditions.
A projection scheme for Navier‐Stokes with variable viscosity and natural boundary condition
Authors: Plasman L. , Deteix J. , Yakoubi D. 
Published: May 2020

SummaryCombiningthe Navier‐Stokes systems with Neumann (or natural) boundary condition to characterize a fluid flow is frequent. The popular projection (or pressure correction) methods inspired by Chorin and Temam are not well adapted to such boundary condition, which translate in loss of accuracy. If some alternative projection methods have been proposed to reduce the accuracy loss due to the Neumann condition in case of Newtonian fluids, little has been proposed for generalized Newtonian fluids. In this work, we propose two methods derived from the incremental pressure correction projection that can be used for fluids with inhomogeneous or variable viscosity with natural boundary condition. Both time and space accuracy of the methods will be illustrated using a manufactured solution.
Adaptive mesh refinement for simulating fluid‐structure interaction using a sharp interface immersed boundary method
Authors: Wang Zhuo , Du Lin , Sun Xiaofeng 
Published: May 2020

SummaryIn this article, adaptive mesh refinement (AMR) is performed to simulate flow around both stationary and moving boundaries. The finite‐difference approach is applied along with a sharp interface immersed boundary (IB) method. The Lagrangian polynomial is employed to facilitate the interpolation from a coarse to a fine grid level, while a weighted‐average formula is used to transfer variables inversely. To save memory, the finest grid is only generated in the local areas close to the wall boundary, and the mesh is dynamically reconstructed based on the location of the wall boundary. The Navier‐Stokes equations are numerically solved through the second‐order central difference scheme in space and the third‐order Runge‐Kutta time integration. Flow around a circular cylinder rotating in a square domain is firstly simulated to examine the accuracy and convergence rate. Then three cases are investigated to test the validity of the present method: flow past a stationary circular cylinder at low Reynolds numbers, flow past a forced oscillating circular cylinder in the transverse direction at various frequencies, and a free circular cylinder subjected to vortex‐induced vibration in two degrees of freedom. Computational results agree well with these in the literature and the flow fields are smooth around the interface of different refinement levels. The effect of refinement level has also been evaluated. In addition, a study for the computational efficiency shows that the AMR approach is helpful to reduce the total node number and speed up the time integration, which could prompt the application of the IB method when a great near‐wall spatial resolution is required.
Uniformly convergent numerical method for singularly perturbed convection‐diffusion type problems with nonlocal boundary condition
Authors: Debela Habtamu Garoma , Duressa Gemechis File 
Published: May 2020

SummaryIn this article, we consider a class of singularly perturbed differential equations of convection‐diffusion type with nonlocal boundary conditions. A uniformly convergent numerical method is constructed via nonstandard finite difference and numerical integration methods to solve the problem. The nonlocal boundary condition is treated using numerical integration techniques. Maximum absolute errors and rates of convergence for different values of perturbation parameter and mesh sizes are tabulated for the numerical example considered. The method is shown to be ϵ‐uniformly convergent.
L1‐type smoothness indicators based weighted essentially nonoscillatory scheme for Hamilton‐Jacobi equations
Authors: Rathan Samala 
Published: May 2020

SummaryThis article presents an improved fifth‐order finite difference weighted essentially nonoscillatory (WENO) scheme to solve Hamilton‐Jacobi equations. A new type of nonlinear weights is introduced with the construction of local smoothness indicators on each local stencil that are measured with the help of generalized undivided differences in L1‐norm. A novel global smoothness measurement is also constructed with the help of local measurements from its linear combination. Numerical experiments are conducted in one‐ and two‐dimensions to demonstrate the performance enhancement, resolution power, numerical accuracy for the proposed scheme, and compared it with the classical WENO scheme.
Political risks and foreign direct investments by multinational corporations: A reference point approach
Authors: Yasuda Naoki , Kotabe Masaaki 
Published: May 2020

AbstractResearch SummaryThe purpose of this study is to develop a behavioral framework for management decision‐making under bounded rationality to analyze foreign direct investments and political risks in host countries. This study shows that managers construct reference points on political risks and assess actual political risks in host countries relative to these reference points. This study considers that the political risk reference point is a mental map made up of (a) perceived political risks in host countries where multinational corporations (MNCs) operate and (b) home country political risks. We find that MNCs interpret political risks in host countries as opportunities (threats) if the political risks are below (above) their reference points. Our study provides a significant contribution to the literature on microfoundations of location strategy.Managerial SummaryPrior empirical studies have found both positive and negative effects of political risks on MNCs' investments. This study develops a behavioral framework for MNCs' boundedly rational decision‐making in political risk assessment. Characterizing political risks in host countries by the concept of a political risk reference point resolves the contradictory findings in the literature. Using data from the global mining industry, we find that MNCs interpret political risks in host countries as opportunities (threats) if the political risks are below (above) their PRRPs. We also show that the other competing companies' reference points do not have significant effects on MNCs' investment decisions. These findings offer managerial implications because they help managers predict competitors' actions.
Supplier evolution in global value chains and the new brand game from an attention‐based view
Authors: Lechner Christian , Lorenzoni Gianni , Guercini Simone , Gueguen Gaël 
Published: May 2020

AbstractResearch SummarySuppliers from emerging economies have been particularly active in acquiring brands from advanced economies. We analyze changes in the global value chain (GVC) of the sports shoe industry and show how hollowing out the asset bases of brand‐holding firms through increasing outsourcing has enabled the emergence of rising power firms, as well as a new brand game and a market for brands. These developments in the GVC might be a future challenge for traditional brand‐holding lead firms. We show that managers focused on branding and distribution issues were myopic towards the strategic initiatives of suppliers. Managers need to pay attention to the potential long‐term consequences of outsourcing and offshoring activities, as suppliers could become competitors or acquirers of their order‐giving firms, leading to the question: Are we approaching a state of dual GVC leadership, or do lead firms risk being kicked out by their suppliers?Managerial SummaryWe explore the emergence of rising power firms from the peripheries of GVCs. An increasing number of major brand‐holding companies from traditionally industrialized economies have been acquired by suppliers from newly industrialized economies due to some fundamental changes. First, the emergence of a market for brands makes brands more volatile. Second, continuous outsourcing and hollowing‐out of the lead firm's asset base has reduced their ability to control the GVC. Through a longitudinal case study analysis, by adopting an attention‐based view, we investigate the behavior of the traditional lead firms. Lead firms were not only myopic to the activities of their suppliers, but their focus on downstream activities created increasing opportunity spaces upstream for rising power firms while weakening the defense capacity of brands.
A numerical investigation of bedrock groundwater recharge and exfiltration on soil mantled hillslopes
Authors: Gardner W. Payton , Jensco Kelsey , H. Hoylman Zachary , Livesay Robert , P. Maneta Marco 
Published: May 2020

AbstractHere we use Richards Equation models of variably saturated soil and bedrock groundwater flow to investigate first‐order patterns of the coupling between soil and bedrock flow systems. We utilize a Monte Carlo sensitivity analysis to identify important hillslope parameters controlling bedrock recharge and then model the transient response of bedrock and soil flow to seasonal precipitation. Our results suggest that hillslopes can be divided into three conceptual zones of groundwater interaction, (a) the zone of lateral unsaturated soil moisture accumulation (upper portion of hillslope), (b) the zone of soil saturation and bedrock recharge (middle of hillslope) and (c) the zone of saturated‐soil lateral flow and bedrock groundwater exfiltration (bottom of hillslope). Zones of groundwater interaction expand upslope during periods of precipitation and drain downslope during dry periods. The amount of water partitioned to the bedrock groundwater system a can be predicted by the ratio of bedrock to soil saturated hydraulic conductivity across a variety of hillslope configurations. Our modelled processes are qualitatively consistent with observations of shallow subsurface saturation and groundwater fluctuation on hillslopes studied in our two experimental watersheds and support a conceptual model of tightly coupled shallow and deep subsurface circulation where groundwater recharge and discharge continuously stores and releases water from longer residence time storage.
Land use change effects on catchment streamflow response in a humid tropical montane cloud forest region, central Veracruz, Mexico
Authors: López‐Ramírez Sergio M. , Sáenz Leonardo , Mayer Alex , Muñoz‐Villers Lyssette E. , Asbjornsen Heidi , Berry Z. Carter , Looker Nathaniel , Manson Robert , Gómez‐Aguilar León Rodrigo 
Published: May 2020

AbstractTropical montane cloud forests (TMCF) are recognized for their capacity to maintain high dry‐season baseflow and a host of other ecosystem services. Substantial areas of TMCF have been converted to pasture and crops such as coffee, while in other areas TCMF are recovering. However, little is known about the effects of this complex dynamic on catchment hydrology. We investigated the effect of land use on rainfall‐runoff response in five neighbouring headwater micro‐catchments in central Veracruz, Mexico, dominated by either mature TMCF (MF), young (20 year‐old) and intermediate (40 year‐old) naturally regenerating TMCF (YF and IF, respectively), shaded coffee (SC), and an intensively grazed pasture (IP). We used a 4‐year record of high‐resolution rainfall and streamflow (10 min) data collected from 2015 to 2019. These data were analysed via comparison of hydrologic metrics that summarize streamflow responses at various time scales and magnitudes. Results showed no statistical difference in the regulation capacity of high flows in the micro‐catchment with 20 years of natural regeneration, compared to the MF. In terms of baseflow sustenance, our results support the hypothesis that MF and IF better promote this hydrologic service than the other land uses. SC exhibited a high capacity to modulate peak flows comparable to that of MF, and an intermediate capacity to sustain baseflow, suggesting that the integrated functioning of this micro‐catchment was largely preserved. Finally, 40 years of intense pasture management was found to have degraded the soil hydraulic properties of IP; mainly, reducing its infiltration capacity, causing a fivefold greater peak flow response and a lower baseflow compared to MF.
Storm event sediment fingerprinting for temporal and spatial sediment source tracing
Authors: Vale Simon S. , Fuller Ian C. , Procter Jonathan N. , Basher Les R. , Dymond John R. 
Published: May 2020

AbstractSediment fingerprinting has been widely used to distinguish discrete sediment sources; however, application to intra‐storm sediment source variability has received relatively little focus despite the benefit being long recognized. In this investigation, sediment fingerprinting was applied to a 53‐hr storm event sampled hourly to determine sediment source dynamics throughout the event. Sediment sources were differentiated using 16 variables, and source contribution determined using Bayesian and Frequentist mixing models for comparison. Both models provided comparable source predictions for the dominant source estimates and the general temporal pattern. The Frequentist model appeared to exhibit some unreliable values coinciding with low GOF and attributed to inherent model structure. The Bayesian model showed higher uncertainty, likely due to the “process error” utilized associated with single sample mixtures. High variability in sediment source contribution was observed between hourly time steps; however, local smoothing reveals temporal trends during the event. A higher average proportion of mudstone is found in the falling limb (0.544) compared with the rising limb (0.464), and the reverse is observed for mountain range (0.218 vs. 0.283) and unconsolidated (0.073 vs. 0.055). In the initial hours of the storm, mudstone source contribution significantly drops, whereas mountain range and unconsolidated contributions peak. The SSC‐Q clockwise hysteresis indicates proximal sediment sources, suggesting the mudstone sediment is stored channel sediment and easily entrained. This sediment flushes through, coinciding with a drop as the distal mountain range and unconsolidated sources arrive to peak contribution. The wider Manawatū discharge and sediment load then arrive, delivering increasing levels of mudstone throughout the remainder of the event while mountain range sediment diminishes. Spatial representation of the sediment source contribution was derived from distributing sediment source loads to the spatial extent of the source material according to sub‐catchment sediment loads and was weighted according to slope. This provided an effective means to visualize the origin of the sediment and a better spatial interpretation of sediment fingerprinting results, which is typically limited by poor spatial resolution.
Forests and floods: Using field evidence to reconcile analysis methods
Authors: Bathurst James C. , Fahey Barry , Iroumé Andrés , Jones Julia 
Published: May 2020

AbstractThe extent to which forests, relative to shorter vegetation, mitigate flood peak discharges remains controversial and relatively poorly researched, with only a few significant field studies. Considering the effect purely of change of vegetation cover, peak flow magnitude comparisons for paired catchments have suggested that forests do not mitigate large floods, whereas flood frequency comparisons have shown that forests mitigate frequencies over all magnitudes of flood. This study investigates the apparent inconsistency using field‐based evidence from four contrasting field programmes at scales of 0.34–3.1 km2. Repeated patterns are identified that provide strong evidence of real effects with physical explanations. Magnitude and frequency comparisons are both relevant to the impact of forests on peak discharges but address different questions. Both can show a convergence of response between forested and grassland/logged states at the highest recorded flows but the associated return periods may be quite variable and are subject to estimation uncertainty. For low to moderate events, the forested catchments have a lower peak magnitude for a given frequency than the grassland/logged catchments. Depending on antecedent soil saturation, a given storm may nevertheless generate peak discharges of the same magnitude for both catchment states but these peaks will have different return periods. The effect purely of change in vegetation cover may be modified by additional forestry interventions, such as road networks and drainage ditches which, by effectively increasing the drainage density, may increase peak flows for all event magnitudes. For all the sites, forest cover substantially reduces annual runoff.
Loss of microRNA‐21 leads to profound stromal remodeling and short survival in K‐Ras‐driven mouse models of pancreatic cancer
Authors: Schipper Josh , Westerhuis Jennifer J. , Beddows Ian , Madaj Zach , Monsma David , Hostetter Galen , Kiupel Matti , Conejo‐Garcia Jose R. , Sempere Lorenzo F. 
Published: May 2020

AbstractThe microenvironment of pancreatic cancer adenocarcinoma (PDAC) is highly desmoplastic with distinct tumor‐restraining and tumor‐promoting fibroblast subpopulations. Re‐education rather than indiscriminate elimination of these fibroblasts has emerged as a new strategy for combination therapy. Here, we studied the effects of global loss of profibrotic noncoding regulatory microRNA‐21 (miR‐21) in K‐Ras‐driven p53‐deleted genetically engineered mouse models of PDAC. Strikingly, loss of miR‐21 accelerated tumor initiation via mucinous cystic neoplastic lesions and progression to locally advanced invasive carcinoma from which animals precipitously succumbed at an early age. The absence of tumor‐restraining myofibroblasts and a massive infiltrate of immune cells were salient phenotypic features of global miR‐21 loss. Stromal miR‐21 activity was required for induction of tumor‐restraining myofibroblasts in in vivo isograft transplantation experiments. Low miR‐21 expression negatively correlated with a fibroblast gene expression signature and positively with an immune cell gene expression signature in The Cancer Genome Atlas PDAC data set (n = 156) mirroring findings in the mouse models. Our results exposed an overall tumor‐suppressive function of miR‐21 in in vivo PDAC models. These results have important clinical implications for anti‐miR‐21‐based inhibitory therapeutic approaches under consideration for PDAC and other cancer types. Mechanistic dissection of the cell‐intrinsic role of miR‐21 in cancer‐associated fibroblasts and other cell types will be needed to inform best strategies for pharmacological modulation of miR‐21 activity to remodel the tumor microenvironment and enhance treatment response in PDAC.
U.S.‐Thai Consortium for the development of pharmacy education in Thailand: History, progress, and impact
Authors: Nathisuwan Surakit , Pattharachayakul Sutthiporn , Subongkot Suphat , Doungngern Thitima , Jones Sirada M. , Engle Janet P. , Lau Alan , Katz Michael D. , Moreton Julian Edward , Ryan Melody 
Published: May 2020

AbstractIn Thailand during the early 1990s, there was a need for an increased number of pharmacists and expansion of their knowledge and skills to address the need of the nation. Leaders of the Thai pharmacy education community at the time crafted a long‐term plan aiming to expand the pharmacy educator workforce at a national scale through the financial support of the Royal Thai Government. This led to the establishment of the United States‐Thai Consortium for the Development of Pharmacy Education in Thailand in 1994. The aim of the Consortium was to advance pharmacy education in Thailand through the support of leading U.S. pharmacy schools using both short‐term and long‐term trainings. Twenty plus years later, pharmacy education and practice in Thailand have changed dramatically. The number of faculties (schools) of pharmacy in Thailand has increased from 10 in 1993 to 19 in 2013. The ratio of pharmacists to population has decreased from 1:10532 in 1994 to 1:2261 in 2016. The professional pharmacy curriculum has changed from a 5‐year bachelor to a 6‐year Doctor of Pharmacy (Pharm.D.) degree. The role of Thai pharmacists has been endorsed by national health service initiatives and practice guidelines. Currently, 7 universities offer residency/fellowship programs. The 8 Thai founding institutions of the Consortium are now publishing over 500 papers in high‐quality international journals annually. In summary, pharmacy education, practice, and research in Thailand have improved dramatically through the U.S.‐Thai Pharmacy Consortium. This bi‐national model of knowledge and skill transfer may serve as an example for how a large‐scale international partnership can facilitate a rapid and positive transformation of pharmacy in a developing country. Local adjustment and adaptation are required to reflect national identity and to suit the local context.
Computed tomography for in vivo deep over‐1000 nm near‐infrared fluorescence imaging
Authors: Umezawa Masakazu , Sera Toshihiro , Yokota Hideo , Takematsu Maho , Morita Masahiko , Yeroslavsky Gil , Kamimura Masao , Soga Kohei 
Published: May 2020

AbstractThis study aims to develop a novel cross‐sectional imaging of fluorescence in over‐1000 nm near‐infrared (OTN‐NIR), which allows in vivo deep imaging, using computed tomography (CT) system. Cylindrical specimens of composite of OTN‐NIR fluorophore, NaGdF4 co‐doped with Yb3+ and Ho3+ (ex: 980 nm, em: 1150 nm), were embedded in cubic agar (10.5–12 mm) or in the peritoneal cavity of mice and placed on a rotatable stage. When the fluorescence from inside of the samples was serially captured from multiple angles, the images were disrupted by the reflection and refraction of emitted light on the sample‐air interface. Immersing the sample into water filled in a rectangular bath suppressed the disruption at the interface and successfully reconstructed the position and concentration of OTN‐NIR fluorophores on the cross‐sectional images using a CT technique. This is promising as a novel three‐dimensional imaging technique for OTN‐NIR fluorescent image projections of small animals captured from multiple angles.