bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ionospheric Irregularities at Mars Probed by MARSIS Topside Sounding
Authors: Harada Y. , Gurnett D. A. , Kopf A. J. , Halekas J. S. , Ruhunusiri S. 
Published: January 2018

AbstractThe upper ionosphere of Mars contains a variety of perturbations driven by solar wind forcing from above and upward propagating atmospheric waves from below. Here we explore the global distribution and variability of ionospheric irregularities around the exobase at Mars by analyzing topside sounding data from the Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS) instrument on board Mars Express. As irregular structure gives rise to off‐vertical echoes with excess propagation time, the diffuseness of ionospheric echo traces can be used as a diagnostic tool for perturbed reflection surfaces. The observed properties of diffuse echoes above unmagnetized regions suggest that ionospheric irregularities with horizontal wavelengths of tens to hundreds of kilometers are particularly enhanced in the winter hemisphere and at high solar zenith angles. Given the known inverse dependence of neutral gravity wave amplitudes on the background atmospheric temperature, the ionospheric irregularities probed by MARSIS are most likely associated with plasma perturbations driven by atmospheric gravity waves. Though extreme events with unusually diffuse echoes are more frequently observed for high solar wind dynamic pressures during some time intervals, the vast majority of the diffuse echo events are unaffected by varying solar wind conditions, implying limited influence of solar wind forcing on the generation of ionospheric irregularities. Combination of remote and in situ measurements of ionospheric irregularities would offer the opportunity for a better understanding of the ionospheric dynamics at Mars.
The Interactive Effect of Multiple Stressors on Crustacean Zooplankton Communities in Montane Lakes
Authors: Brittain Jeffrey T. , Strecker Angela L. 
Published: January 2018

AbstractNonnative fish introductions have altered thousands of naturally fishless montane lakes, resulting in cascading food web repercussions. Nitrogen deposition has been recognized as an anthropogenic contributor to acidification and eutrophication of freshwater ecosystems, which may affect the abundance and composition of planktonic communities. This study identified responses of zooplankton communities from two lakes (fish present versus absent) in Mount Rainier National Park to manipulations simulating an episodic disturbance of acidification and eutrophication via nitrogen addition in mesocosms. Zooplankton communities from lakes with different food web structure (i.e., fish present or absent) responded differently to the singular effects of acid and nitrogen addition. For instance, zooplankton biomass decreased in the acid treatment of the fishless lake experiment, but increased in response to acid in the fish‐present experiment. In contrast, the combination of acid and nitrogen often resulted in weak responses for both lake types, resulting in nonadditive effects, i.e., the net effect of the stressors was in the opposite direction than predicted, which is known as a reversal or “ecological surprise.” This experiment demonstrates the difficulty in predicting the interactive effects of multiple stressors on aquatic communities, which may pose significant challenges for habitat restoration through fish removal.
Estimating Wetland Connectivity to Streams in the Prairie Pothole Region: An Isotopic and Remote Sensing Approach
Authors: Brooks J. R. , Mushet D. M. , Vanderhoof M. K. , Leibowitz S. G. , Christensen J. R. , Neff B. P. , Rosenberry D. O. , Rugh W. D. , Alexander L. C. 
Published: January 2018

AbstractUnderstanding hydrologic connectivity between wetlands and perennial streams is critical to understanding the reliance of stream flow on inputs from wetlands. We used the isotopic evaporation signal in water and remote sensing to examine wetland‐stream hydrologic connectivity within the Pipestem Creek watershed, North Dakota, a watershed dominated by prairie‐pothole wetlands. Pipestem Creek exhibited an evaporated‐water signal that had approximately half the isotopic‐enrichment signal found in most evaporatively enriched prairie‐pothole wetlands. Groundwater adjacent to Pipestem Creek had isotopic values that indicated recharge from winter precipitation and had no significant evaporative enrichment, indicating that enriched surface water did not contribute significantly to groundwater discharging into Pipestem Creek. The estimated surface water area necessary to generate the evaporation signal within Pipestem Creek was highly dynamic, varied primarily with the amount of discharge, and was typically greater than the immediate Pipestem Creek surface water area, indicating that surficial flow from wetlands contributed to stream flow throughout the summer. We propose a dynamic range of spilling thresholds for prairie‐pothole wetlands across the watershed allowing for wetland inputs even during low‐flow periods. Combining Landsat estimates with the isotopic approach allowed determination of potential (Landsat) and actual (isotope) contributing areas in wetland‐dominated systems. This combined approach can give insights into the changes in location and magnitude of surface water and groundwater pathways over time. This approach can be used in other areas where evaporation from wetlands results in a sufficient evaporative isotopic signal.
Accuracy of Snow Water Equivalent Estimated From GPS Vertical Displacements: A Synthetic Loading Case Study for Western U.S. Mountains
Authors: Enzminger Thomas L. , Small Eric E. , Borsa Adrian A. 
Published: January 2018

AbstractGPS monitoring of solid Earth deformation due to surface loading is an independent approach for estimating seasonal changes in terrestrial water storage (TWS). In western United States (WUSA) mountain ranges, snow water equivalent (SWE) is the dominant component of TWS and an essential water resource. While several studies have estimated SWE from GPS‐measured vertical displacements, the error associated with this method remains poorly constrained. We examine the accuracy of SWE estimated from synthetic displacements at 1,395 continuous GPS station locations in the WUSA. Displacement at each station is calculated from the predicted elastic response to variations in SWE from SNODAS and soil moisture from the NLDAS‐2 Noah model. We invert synthetic displacements for TWS, showing that both seasonal accumulation and melt as well as year‐to‐year fluctuations in peak SWE can be estimated from data recorded by the existing GPS network. Because we impose a smoothness constraint in the inversion, recovered TWS exhibits mass leakage from mountain ranges to surrounding areas. This leakage bias is removed via linear rescaling in which the magnitude of the gain factor depends on station distribution and TWS anomaly patterns. The synthetic GPS‐derived estimates reproduce approximately half of the spatial variability (unbiased root mean square error ∼50%) of TWS loading within mountain ranges, a considerable improvement over GRACE. The inclusion of additional simulated GPS stations improves representation of spatial variations. GPS data can be used to estimate mountain‐range‐scale SWE, but effects of soil moisture and other TWS components must first be subtracted from the GPS‐derived load estimates.
Estimating Discharge in Low‐Order Rivers With High‐Resolution Aerial Imagery
Authors: King Tyler V. , Neilson Bethany T. , Rasmussen Mitchell T. 
Published: January 2018

AbstractRemote sensing of river discharge promises to augment in situ gauging stations, but the majority of research in this field focuses on large rivers (>50 m wide). We present a method for estimating volumetric river discharge in low‐order (<50 m wide) rivers from remotely sensed data by coupling high‐resolution imagery with one‐dimensional hydraulic modeling at so‐called virtual gauging stations. These locations were identified as locations where the river contracted under low flows, exposing a substantial portion of the river bed. Topography of the exposed river bed was photogrammetrically extracted from high‐resolution aerial imagery while the geometry of the remaining inundated portion of the channel was approximated based on adjacent bank topography and maximum depth assumptions. Full channel bathymetry was used to create hydraulic models that encompassed virtual gauging stations. Discharge for each aerial survey was estimated with the hydraulic model by matching modeled and remotely sensed wetted widths. Based on these results, synthetic width‐discharge rating curves were produced for each virtual gauging station. In situ observations were used to determine the accuracy of wetted widths extracted from imagery (mean error 0.36 m), extracted bathymetry (mean vertical RMSE 0.23 m), and discharge (mean percent error 7% with a standard deviation of 6%). Sensitivity analyses were conducted to determine the influence of inundated channel bathymetry and roughness parameters on estimated discharge. Comparison of synthetic rating curves produced through sensitivity analyses show that reasonable ranges of parameter values result in mean percent errors in predicted discharges of 12%–27%.
Tuning Fractures With Dynamic Data
Authors: Yao Mengbi , Chang Haibin , Li Xiang , Zhang Dongxiao 
Published: January 2018

AbstractFlow in fractured porous media is crucial for production of oil/gas reservoirs and exploitation of geothermal energy. Flow behaviors in such media are mainly dictated by the distribution of fractures. Measuring and inferring the distribution of fractures is subject to large uncertainty, which, in turn, leads to great uncertainty in the prediction of flow behaviors. Inverse modeling with dynamic data may assist to constrain fracture distributions, thus reducing the uncertainty of flow prediction. However, inverse modeling for flow in fractured reservoirs is challenging, owing to the discrete and non‐Gaussian distribution of fractures, as well as strong nonlinearity in the relationship between flow responses and model parameters. In this work, building upon a series of recent advances, an inverse modeling approach is proposed to efficiently update the flow model to match the dynamic data while retaining geological realism in the distribution of fractures. In the approach, the Hough‐transform method is employed to parameterize non‐Gaussian fracture fields with continuous parameter fields, thus rendering desirable properties required by many inverse modeling methods. In addition, a recently developed forward simulation method, the embedded discrete fracture method (EDFM), is utilized to model the fractures. The EDFM maintains computational efficiency while preserving the ability to capture the geometrical details of fractures because the matrix is discretized as structured grid, while the fractures being handled as planes are inserted into the matrix grids. The combination of Hough representation of fractures with the EDFM makes it possible to tune the fractures (through updating their existence, location, orientation, length, and other properties) without requiring either unstructured grids or regridding during updating. Such a treatment is amenable to numerous inverse modeling approaches, such as the iterative inverse modeling method employed in this study, which is capable of dealing with strongly nonlinear problems. A series of numerical case studies with increasing complexity are set up to examine the performance of the proposed approach.
Evaluation of the location potential of commercial facilities as a place of refuge: A case study on facilities providing food in the Kii Peninsula
Authors: Sanuki Ryo , Satoh Eiji , Suzuki Tatsuya , Yoshikawa Tohru , Maki Norio 
Published: January 2018

AbstractThe purpose of the study is to analyze the effect of establishing places of refuge in commercial facilities in addition to public facilities. To this end, the differences in accessibility of the places of refuge were analyzed across the Kii Peninsula and Matsuzaka City among various cases of facilities providing food. The analysis of the Kii Peninsula shows that supermarkets would be most useful. The analysis in Matsuzaka City shows that the facilities providing food would be useful to increase robustness and decrease the distance to refuges but less effective than refuge buildings on the coast in case of tsunami.
Teaching Grammar: Form–Meaning Mapping
Authors: Gardner Sheena 
Published: January 2018

With advances in corpus‐informed descriptions of patterns in English grammar, research has revealed a wealth of detailed, specific, and meaningful form–meaning mappings and frequency information that provide teachers with attested examples of items with similar grammatical patterns and similar meanings. Starting from a discourse‐ or genre‐based approach has led to a complementary set of meaning–form mappings. Both sets can usefully inform grammar instruction, teaching materials, and syllabus plans.
With connectionist research exploring form–meaning mappings in the brain through studies of processing time, and SLA theorists arguing for deep processing for effective learning, there has been a rise in popularity of approaches to teaching grammar that aim to encourage learners to work at making the connections between grammatical forms and associated meanings. A range of techniques compatible with this general approach are presented in this entry within a discussion of principles for teaching grammatical form–meaning mappings.
Teaching/Developing Vocabulary Using Semantic Feature Analysis
Authors: Amer Aly 
Published: January 2018

Recent developments in “lexical semantics” have prompted the development of the “semantic field theory,” or “semantic features analysis” approaches, which organize words in terms of interrelated lexical meanings. Research has shown that semantic feature analysis is a powerful strategy that mimics the way the brain organizes information. SFA suggests that the lexical content of a language is best treated not as an unstructured list of words but as a collection of interrelating networks of relations between words. Hence, it is plausible to assume that a method of teaching that takes account of the psychological processes underlying semantic relatedness must be more effective pedagogically than one that does not.The present entry discusses the pedagogic implications of “semantic feature analysis” to second language vocabulary teaching and learning.
Teaching/Developing Vocabulary Through Word Origins, Root Words, Prefixes and Suffixes
Authors: Hirsh David 
Published: January 2018

The idea of word origins has attracted some attention in first language reading contexts, with discussions regarding the ability of children to decode words. In second language learning contexts, there has been some interest in the ability of language learners to recognize some of the more frequently occurring and regular prefixes and suffixes, as part of a broader interest in the concept of word families. The thinking is that, with increased exposure to the language, learners may be able to apply knowledge of prefixes and suffixes to help with processing new words met while reading.
Following this line of thinking, the language teacher could assist language learners with becoming familiar with the form, meaning, and use of the most commonly occurring and salient prefixes and suffixes, as a tool to assist with processing unknown words met in written and spoken texts.
Peace Corps Volunteers as Teachers of English
Authors: Clark Bernadine , Clark Kenneth 
Published: January 2018

Peace Corps Volunteers have been teaching English in countries requesting training assistance from the United States since the beginnings of the Peace Corps in 1961. The Volunteers, guided by the Peace Corps mission to promote world peace and friendship and three goals linked implicitly to learning and explicitly to intercultural understanding, teach in schools and universities and serve as English language resources in their host communities.
As a collective, Peace Corps Volunteer teachers of English are distinguished from many paid English teachers working internationally. The Volunteers are US citizens whose characteristics include a belief in a humanitarian service, an adaptability for teaching English in under‐resourced settings, and a level of cultural sensitivity and awareness that informs their teaching. Because Volunteers' teaching credentials vary widely, Peace Corps developed a TEFL certificate program to reflect 21st‐century global English‐teaching standards, meet host‐country language learners' needs, and support the ongoing professional development of Volunteer teachers.
Dual Role of Subphthalocyanine Dyes for Optical Imaging and Therapy of Cancer
Authors: van de Winckel Eveline , Mascaraque Marta , Zamarrón Alicia , Juarranz de la Fuente Ángeles , Torres Tomás , de la Escosura Andrés 
Published: January 2018

AbstractThe family of subphthalocyanine (SubPc) macrocycles represents an interesting class of nonplanar aromatic dyes with promising features for energy conversion and optoelectronics. The use of SubPcs in biomedical research is, on the contrary, clearly underexplored, despite their documented high fluorescence and singlet oxygen quantum yields. Herein, for the first time it is shown that the interaction of these chromophores with light can also be useful for theranostic applications, which in the case of SubPcs comprise optical imaging and photodynamic therapy (PDT). In particular, the article evaluates, through a complete in vitro study, the dual‐role capacity of a novel series of SubPcs as fluorescent probes and PDT agents, where the macrocycle axial substitution determines their biological activity. The 2D and 3D imaging of various cancer cell lines (i.e., HeLa, SCC‐13, and A431) has revealed, for example, different subcellular localization of the studied photosensitizers (PS), depending on the axial substituent they bear. These results also show excellent photocytotoxicities, which are affected by the PS localization. With the best dual‐role PS, preliminary in vivo studies have demonstrated their therapeutic potential. Overall, the present paper sets the bases for an unprecedented biomedical use of these well‐known optoelectronic materials.
Dependence of Photocurrent Enhancements in Quantum Dot (QD)‐Sensitized MoS2 Devices on MoS2 Film Properties
Authors: Gough John J. , McEvoy Niall , O'Brien Maria , Bell Alan P. , McCloskey David , Boland John B. , Coleman Jonathan N. , Duesberg Georg S. , Bradley A. Louise 
Published: January 2018

AbstractThis report demonstrates highly efficient nonradiative energy transfer (NRET) from alloyed CdSeS/ZnS semiconductor nanocrystal quantum dots (QDs) to MoS2 films of varying layer thicknesses, including pristine monolayers, mixed monolayer/bilayer, polycrystalline bilayers, and bulk‐like thicknesses, with NRET efficiencies of over 90%. Large‐area MoS2 films are grown on Si/SiO2 substrates by chemical vapor deposition. Despite the ultrahigh NRET efficiencies there is no distinct increase in the MoS2 photoluminescence intensity. However, by studying the optoelectronic properties of the MoS2 devices before and after adding the QD sensitizing layer photocurrent enhancements as large as ≈14‐fold for pristine monolayer devices are observed, with enhancements on the order of ≈2‐fold for MoS2 devices of mixed monolayer and bilayer thicknesses. For the polycrystalline bilayer and bulk‐like MoS2 devices there is almost no increase in the photocurrent after adding the QDs. Industrially scalable techniques are specifically utilized to fabricate the samples studied in this report, demonstrating the viability of this hybrid structure for commercial photodetector or light harvesting applications.
4D Biofabrication: 3D Cell Patterning Using Shape‐Changing Films
Authors: Stroganov Vladislav , Pant Jitendra , Stoychev Georgi , Janke Andreas , Jehnichen Dieter , Fery Andreas , Handa Hitesh , Ionov Leonid 
Published: January 2018

AbstractA novel approach for fabrication of 3D cellular structures using new thermosensitive shape‐changing polymer films with photolithographically patterned surface—4D biofabrication is reported. The surface of shape‐changing polymer films is patterned to selectively adsorb cells in specific regions. The 2D cell pattern is converted to the 3D cell structure after temperature‐induced folding of the polymer films. This approach has a great potential in the field of tissue engineering and bioscaffolds fabrication.
Flexoelectricity in Bones
Authors: Vasquez‐Sancho Fabian , Abdollahi Amir , Damjanovic Dragan , Catalan Gustau 
Published: January 2018

AbstractBones generate electricity under pressure, and this electromechanical behavior is thought to be essential for bone's self‐repair and remodeling properties. The origin of this response is attributed to the piezoelectricity of collagen, which is the main structural protein of bones. In theory, however, any material can also generate voltages in response to strain gradients, thanks to the property known as flexoelectricity. In this work, the flexoelectricity of bone and pure bone mineral (hydroxyapatite) are measured and found to be of the same order of magnitude; the quantitative similarity suggests that hydroxyapatite flexoelectricity is the main source of bending‐induced polarization in cortical bone. In addition, the measured flexoelectric coefficients are used to calculate the (flexo)electric fields generated by cracks in bone mineral. The results indicate that crack‐generated flexoelectricity is theoretically large enough to induce osteocyte apoptosis and thus initiate the crack‐healing process, suggesting a central role of flexoelectricity in bone repair and remodeling.
Electrocatalytic Activity of a 2D Phosphorene‐Based Heteroelectrocatalyst for Photoelectrochemical Cells
Authors: Batmunkh Munkhbayar , Shrestha Aabhash , Bat‐Erdene Munkhjargal , Nine Md Julker , Shearer Cameron J. , Gibson Christopher T. , Slattery Ashley D. , Tawfik Sherif Abdulkader , Ford Michael J. , Dai Sheng , Qiao Shizhang , Shapter Joseph G. 
Published: January 2018

AbstractResearch into efficient synthesis, fundamental properties, and potential applications of phosphorene is currently the subject of intense investigation. Herein, solution‐processed phosphorene or few‐layer black phosphorus (FL‐BP) sheets are prepared using a microwave exfoliation method and used in photoelectrochemical cells. Based on experimental and theoretical (DFT) studies, the FL‐BP sheets are found to act as catalytically active sites and show excellent electrocatalytic activity for triiodide reduction in dye‐sensitized solar cells. Importantly, the device fabricated based on the newly designed cobalt sulfide (CoSx) decorated nitrogen and sulfur co‐doped carbon nanotube heteroelectrocatalyst coated with FL‐BP (FL‐BP@N,S‐doped CNTs‐CoSx) displayed an impressive photovoltaic efficiency of 8.31 %, outperforming expensive platinum based cells. This work paves the way for using phosphorene‐based electrocatalysts for next‐generation energy‐storage systems.
Targeting a Dark Excited State of HIV‐1 Nucleocapsid by Antiretroviral Thioesters Revealed by NMR Spectroscopy
Authors: Deshmukh Lalit , Tugarinov Vitali , Appella Daniel H. , Clore G. Marius 
Published: January 2018

AbstractHIV‐1 nucleocapsid (NCp7) is a two Cys2HisCys zinc knuckle (N‐Zn and C‐Zn) protein that plays a key role in viral replication. NCp7 conformational dynamics is characterized by NMR relaxation dispersion and chemical exchange saturation transfer measurements. While the N‐Zn knuckle is conformationally stable, the C‐Zn knuckle interconverts on the millisecond timescale between the major state, in which the zinc is coordinated by three cysteines and a histidine, and two folded minor species (with populations around 1 %) in which one of the coordination bonds (Cys413‐Sγ‐Zn or His421‐Nϵ2‐Zn) is hydrolyzed. These findings explain why antiretroviral thioesters specifically disrupt the C‐Zn knuckle by initial acylation of Cys413, and show that transient, sparsely‐populated (“dark”), excited states of proteins can present effective targets for rational drug design.