bluuebunny/crossref_metadata_2025_split huggingface dataset:
Windows in Arctic sea ice: Light transmission and ice algae in a refrozen lead
Authors: Kauko Hanna M. , Taskjelle Torbjørn , Assmy Philipp , Pavlov Alexey K. , Mundy C. J. , Duarte Pedro , Fernández‐Méndez Mar , Olsen Lasse M. , Hudson Stephen R. , Johnsen Geir , Elliott Ashley , Wang Feiyue , Granskog Mats A. 
Published: June 2017

AbstractThe Arctic Ocean is rapidly changing from thicker multiyear to thinner first‐year ice cover, with significant consequences for radiative transfer through the ice pack and light availability for algal growth. A thinner, more dynamic ice cover will possibly result in more frequent leads, covered by newly formed ice with little snow cover. We studied a refrozen lead (≤0.27 m ice) in drifting pack ice north of Svalbard (80.5–81.8°N) in May–June 2015 during the Norwegian young sea ICE expedition (N‐ICE2015). We measured downwelling incident and ice‐transmitted spectral irradiance, and colored dissolved organic matter (CDOM), particle absorption, ultraviolet (UV)‐protecting mycosporine‐like amino acids (MAAs), and chlorophyll a (Chl a) in melted sea ice samples. We found occasionally very high MAA concentrations (up to 39 mg m−3, mean 4.5 ± 7.8 mg m−3) and MAA to Chl a ratios (up to 6.3, mean 1.2 ± 1.3). Disagreement in modeled and observed transmittance in the UV range let us conclude that MAA signatures in CDOM absorption spectra may be artifacts due to osmotic shock during ice melting. Although observed PAR (photosynthetically active radiation) transmittance through the thin ice was significantly higher than that of the adjacent thicker ice with deep snow cover, ice algal standing stocks were low (≤2.31 mg Chl a m−2) and similar to the adjacent ice. Ice algal accumulation in the lead was possibly delayed by the low inoculum and the time needed for photoacclimation to the high‐light environment. However, leads are important for phytoplankton growth by acting like windows into the water column.
Detection of diffuse seafloor venting using a structured light laser sensor: 2. Evaluation of detection sensitivity and limitations
Authors: Smart Clara , Roman Chris 
Published: June 2017

Algorithms to detect diffuse hydrothermal vent fluids using the structured light laser sensor have proven to be successful. However, potential limitations due to survey parameters, including altitude and vehicle heading, have not been explored and are the focus of this study. Data from 12 surveys conducted over a single hydrothermal vent at three different altitudes (2.7 m, 4.2 m, and 6.2 m) and four different headings are analyzed. Increasing survey altitude decreases the resolution and intensity of the imaged laser line; therefore, range‐dependent processing considerations to maintain detection sensitivity are presented. Analysis of these surveys suggests minimal degradation of vent detection capabilities from survey altitudes up to 6 m. Additionally, as the shape and location of the detected distortion patterns vary with survey heading and altitude they are presented as potential indications of plume shape and rise height. The effects of range and survey heading are important for future applications of this sensor which may include surveying from higher, faster flying autonomous underwater vehicles.
Block motion changes in Japan triggered by the 2011 great Tohoku earthquake
Authors: Meade Brendan J. , Loveless John P. 
Published: June 2017

AbstractPlate motions are governed by equilibrium between basal and edge forces. Great earthquakes may induce differential static stress changes across tectonic plates, enabling a new equilibrium state. Here we consider the torque balance for idealized circular plates and find a simple scalar relationship for changes in relative plate speed as a function of its size, upper mantle viscosity, and coseismic stress changes. Applied to Japan, the 2011
Tohoku earthquake generated coseismic stresses of 102–105 Pa that could have induced changes in motion of small (radius ∼100 km) crustal blocks within Honshu. Analysis of time‐dependent GPS velocities, with corrections for earthquake cycle effects, reveals that plate speeds may have changed by up to ∼3 mm/yr between ∼3.75 year epochs bracketing this earthquake, consistent with an upper mantle viscosity of ∼5 × 1018Pa
s, suggesting that great earthquakes may modulate motions of proximal crustal blocks at frequencies as high as 10−8 Hz.
Tracking Labrador Sea Water property signals along the Deep Western Boundary Current
Authors: Le Bras Isabela Astiz , Yashayaev Igor , Toole John M. 
Published: June 2017

AbstractObservations of the Deep Western Boundary Current (DWBC) at Line W on the western North Atlantic continental slope southeast of Cape Cod from 1995 to 2014 reveal water mass changes that are consistent with changes in source water properties upstream in the Labrador Sea. This is most evident in the cold, dense, and deep class of Labrador Sea Water (dLSW) that was created and progressively replenished and deepened by recurring winter convection during the severe winters of 1987–1994. The arrival of this record cold, fresh, and low potential vorticity anomaly at Line W lags its formation in the Labrador Sea by 3–7 years. Complementary observations along the path of the DWBC provide further evidence that this anomaly is advected along the boundary and indicate that stirring between the boundary and the interior intensifies south of the Flemish Cap. Finally, the consistency of the data with realistic advective and mixing time scales is assessed using the Waugh and Hall (2005) model framework. The data are found to be best represented by a mean transit time of 5 years from the Labrador Sea to Line W, with a leading order role for both advection by the DWBC and mixing between the boundary flow and interior waters.
A statistical assessment of seismic models of the U.S. continental crust using Bayesian inversion of ambient noise surface wave dispersion data
Authors: Olugboji T. M. , Lekic V. , McDonough W. 
Published: June 2017

AbstractWe present a new approach for evaluating existing crustal models using ambient noise data sets and its associated uncertainties. We use a transdimensional hierarchical Bayesian inversion approach to invert ambient noise surface wave phase dispersion maps for Love and Rayleigh waves using measurements obtained from Ekström (2014). Spatiospectral analysis shows that our results are comparable to a linear least squares inverse approach (except at higher harmonic degrees), but the procedure has additional advantages: (1) it yields an autoadaptive parameterization that follows Earth structure without making restricting assumptions on model resolution (regularization or damping) and data errors; (2) it can recover non‐Gaussian phase velocity probability distributions while quantifying the sources of uncertainties in the data measurements and modeling procedure; and (3) it enables statistical assessments of different crustal models (e.g., CRUST1.0, LITHO1.0, and NACr14) using variable resolution residual and standard deviation maps estimated from the ensemble. These assessments show that in the stable old crust of the Archean, the misfits are statistically negligible, requiring no significant update to crustal models from the ambient noise data set. In other regions of the U.S., significant updates to regionalization and crustal structure are expected especially in the shallow sedimentary basins and the tectonically active regions, where the differences between model predictions and data are statistically significant.
The distribution and composition of high‐velocity lower crust across the continental U.S.: Comparison of seismic and xenolith data and implications for lithospheric dynamics and history
Authors: Schulte‐Pelkum Vera , Mahan Kevin H. , Shen Weisen , Stachnik Josh C. 
Published: June 2017

AbstractThe composition of the continental lower crust is not well known. High seismic wave speeds may indicate mafic or garnet‐bearing material, with implications for emplacement history, evolution, and rheological and dynamic behavior. In this contribution, we use recent seismic results from the EarthScope Transportable Array, compilations of active source studies, and selected xenolith studies to attempt to map the distribution of high‐velocity lower crust across the continental U.S. and assess its relationship to proposed emplacement‐ and destruction‐related mechanisms such as underplating and intraplating, collision, extension, heating, cooling, hydration, and delamination. Thin layers of high‐velocity lower crust related to regional processes are found scattered throughout the continent. Thicker layers in large areas are found in the central and eastern U.S. in areas with thick crust, bounded roughly by the Rocky Mountain Front. Emplacement processes likely originally spanned this boundary, and the difference between the two domains may reflect garnet growth with cooling and aging of continental crust in much of the central and eastern U.S., while crustal thickness and lithospheric temperatures in the western U.S. are unfavorable for growth and maintenance of thick layers of high‐velocity garnet‐bearing lower crust.
Opening of the central Atlantic Ocean: Implications for geometric rifting and asymmetric initial seafloor spreading after continental breakup
Authors: Biari Y. , Klingelhoefer F. , Sahabi M. , Funck T. , Benabdellouahed M. , Schnabel M. , Reichert C. , Gutscher M.‐A. , Bronner A. , Austin J. A. 
Published: June 2017

AbstractStudy of the deep structure of conjugate passive continental margins combined with detailed plate kinematic reconstructions can provide constraints on the mechanisms of rifting and formation of initial oceanic crust. In this study the central Atlantic conjugate margins are compared based on compilation of wide‐angle seismic profiles from NW Africa Nova Scotian and U.S. passive margins. The patterns of volcanism, crustal thickness, geometry, and seismic velocities in the transition zone suggest symmetric rifting followed by asymmetric oceanic crustal accretion. Conjugate profiles in the southern central Atlantic image differences in the continental crustal thickness. While profiles on the eastern U.S. margin are characterized by thick layers of magmatic underplating, no such underplate was imaged along the African continental margin. In the north, two wide‐angle seismic profiles acquired in exactly conjugate positions show that the crustal geometry of the unthinned continental crust and the necking zone are nearly symmetric. A region including seismic velocities too high to be explained by either continental or oceanic crust is imaged along the Canadian side, corresponding on the African side to an oceanic crust with slightly elevated velocities. These might result from asymmetric spreading creating seafloor by faulting the existing lithosphere on the Canadian side and the emplacement of magmatic oceanic crust including pockets of serpentinite on the Moroccan margin. After isochron M25, a large‐scale plate reorganization might then have led to an increase in spreading velocity and the production of thin magmatic crust on both sides.
Effect of sampling time in the laboratory investigation of braided rivers
Authors: Vesipa R. , Camporeale C. , Ridolfi L. 
Published: June 2017

AbstractWe focus on the measurement of the bed‐elevation of braided networks in flume experiments. In particular, the effect of the survey frequency on the measurement accuracy is studied. To this aim, an innovative measurement system is adopted. It consists of a laser‐ultrasonic sensor and can survey the bed‐elevation under flowing water. This measurement system was used to profile a flume transect with a frequency of 4 min, without stopping the water discharge. By this technique, the topography of a single transect was continuously acquired during the evolution of a braided river model. Twelve braided rivers generated with different experimental conditions were studied. The main results are (i) there exists a threshold survey frequency (4–8 min in our analysis) which guarantees that the morphological evolution of the braiding channels is fully measured; (ii) if this threshold frequency of survey is exceeded, significant errors occur in the balance of the eroded/deposited sediments and in the evaluation of the bed‐elevation dynamics; and (iii) these errors depend on the river stream power.
High‐frequency dissolved organic carbon and nitrate measurements reveal differences in storm hysteresis and loading in relation to land cover and seasonality
Authors: Vaughan M. C. H. , Bowden W. B. , Shanley J. B. , Vermilyea A. , Sleeper R. , Gold A. J. , Pradhanang S. M. , Inamdar S. P. , Levia D. F. , Andres A. S. , Birgand F. , Schroth A. W. 
Published: June 2017

AbstractStorm events dominate riverine loads of dissolved organic carbon (DOC) and nitrate and are expected to increase in frequency and intensity in many regions due to climate change. We deployed three high‐frequency (15 min) in situ absorbance spectrophotometers to monitor DOC and nitrate concentration for 126 storms in three watersheds with agricultural, urban, and forested land use/land cover. We examined intrastorm hysteresis and the influences of seasonality, storm size, and dominant land use/land cover on storm DOC and nitrate loads. DOC hysteresis was generally anticlockwise at all sites, indicating distal and plentiful sources for all three streams despite varied DOC character and sources. Nitrate hysteresis was generally clockwise for urban and forested sites, but anticlockwise for the agricultural site, indicating an exhaustible, proximal source of nitrate in the urban and forested sites, and more distal and plentiful sources of nitrate in the agricultural site. The agricultural site had significantly higher storm nitrate yield per water yield and higher storm DOC yield per water yield than the urban or forested sites. Seasonal effects were important for storm nitrate yield in all three watersheds and farm management practices likely caused complex interactions with seasonality at the agricultural site. Hysteresis indices did not improve predictions of storm nitrate yields at any site. We discuss key lessons from using high‐frequency in situ optical sensors.
Investigating water use over the Choptank River Watershed using a multisatellite data fusion approach
Authors: Sun Liang , Anderson Martha C. , Gao Feng , Hain Christopher , Alfieri Joseph G. , Sharifi Amirreza , McCarty Gregory W. , Yang Yun , Yang Yang , Kustas William P. , McKee Lynn 
Published: June 2017

AbstractThe health of the Chesapeake Bay ecosystem has been declining for several decades due to high levels of nutrients and sediments largely tied to agricultural production systems. Therefore, monitoring of agricultural water use and hydrologic connections between crop lands and Bay tributaries has received increasing attention. Remote sensing retrievals of actual evapotranspiration (ET) can provide valuable information in support of these hydrologic modeling efforts, spatially and temporally describing consumptive water use by crops and natural vegetation and quantifying response to expansion of irrigated area occurring with Bay watershed. In this study, a multisensor satellite data fusion methodology, combined with a multiscale ET retrieval algorithm, was applied over the Choptank River watershed located within the Lower Chesapeake Bay region on the Eastern Shore of Maryland, USA to produce daily 30 m resolution ET maps. ET estimates directly retrieved on Landsat satellite overpass dates have high accuracy with relative error (RE) of 9%, as evaluated using flux tower measurements. The fused daily ET time series have reasonable errors of 18% at the daily time step ‐ an improvement from 27% errors using standard Landsat‐only interpolation techniques. Annual water consumption by different land cover types was assessed, showing reasonable distributions of water use with cover class. Seasonal patterns in modeled crop transpiration and soil evaporation for dominant crop types were analyzed, and agree well with crop phenology at field scale. Additionally, effects of irrigation occurring during a period of rainfall shortage were captured by the fusion program. These results suggest that the ET fusion system will have utility for water management at field and regional scales over the Eastern Shore. Further efforts are underway to integrate these detailed water use data sets into watershed‐scale hydrologic models to improve assessments of water quality and inform best management practices to reduce nutrient and sediment loads to the Chesapeake Bay.
Unique Structural Design and Strategies for Germanium‐Based Anode Materials Toward Enhanced Lithium Storage
Authors: Li Dan , Wang Hongqiang , Zhou Tengfei , Zhang Wenchao , Liu Hua Kun , Guo Zaiping 
Published: June 2017

AbstractGermanium‐based materials are arousing increasing interest as anodes for lithium‐ion batteries, stemming from the intrinsic physical and chemical advantages of germanium. This progress report provides a brief review on the current development of germanium‐based materials in lithium storage. The state‐of‐the‐art strategies to achieve enhanced electrochemical properties are highlighted, with their main aim being to resolve the trickiest issue: vast volume changes in germanium during cycling. These strategies include structural modification, modification by surface coating, forming germanium‐based alloys, and forming binary or ternary germanium‐based composites. The recent work on a novel composite of germanium and tin particles encapsulated in double‐concentric carbon hollow spheres is also presented here, with an emphasis on the relationship between structural design and improved performance.
A Self‐Powered Dynamic Displacement Monitoring System Based on Triboelectric Accelerometer
Authors: Yu Hua , He Xu , Ding Wenbo , Hu Yongshan , Yang Dongchen , Lu Shan , Wu Changsheng , Zou Haiyang , Liu Ruiyuan , Lu Canhui , Wang Zhong Lin 
Published: June 2017

AbstractAn integrated self‐powered dynamic displacement monitoring system by utilizing a novel triboelectric accelerometer for structural health monitoring is proposed and implemented in this study, which can show the dynamic displacement and transmit the alarming signal by accurately sensing the vibration acceleration. The fabricated triboelectric accelerometer based on the noncontact freestanding triboelectric nanogenerator consists of an outer transparent sleeve tube and an inner cylindrical inertial mass that is suspended by a highly stretchable silicone fiber. One pair of copper film electrodes is deposited by physical vapor deposition on nylon film and adhered on the inner wall of the outer tube, while a fluorinated ethylene propylene film with nanowire structures is adhered on the surface of the inner cylindrical inertial mass. The experimental results show that proposed triboelectric accelerometer can accurately sense the vibration acceleration with a high sensitivity of 0.391 V s2 m−1. In particular, the developed accelerometer has superior performance within the low‐frequency range. One of the most striking features is that the commercial accelerometer using piezoelectric material is strongly dominated by high‐order harmonics, which can cause confusion in computer data analysis. In contrast, the triboelectric accelerometer is only dominated by the base resonance mode.
Breathable Carbon‐Free Electrode: Black TiO2 with Hierarchically Ordered Porous Structure for Stable Li–O2 Battery
Authors: Kang Joonhyeon , Kim Jinyoung , Lee Sangheon , Wi Sungun , Kim Chunjoong , Hyun Seungmin , Nam Seunghoon , Park Yongjoon , Park Byungwoo 
Published: June 2017

AbstractThis paper introduces oxygen‐deficient black TiO2 with hierarchically ordered porous structure fabricated by a simple hydrogen reduction as a carbon‐ and binder‐free cathode, demonstrating superior energy density and stability. With the high electrical conductivity derived from oxygen vacancies or Ti3+ ions, this unique electrode features micrometer‐sized voids with mesoporous walls for the effective accommodation of Li2O2 toroid and for the rapid transport of reaction molecules without the electrode being clogged. In the highly ordered architecture, toroidal Li2O2 particles are guided to form with a regular size and separation, which induces the most of Li2O2 external surface to be directly exposed to the electrolyte. Therefore, large Li2O2 toroids (≈300 nm) grown from solution can be effectively charged by incorporating a soluble catalyst, resulting in a very small polarization (≈0.37 V). Furthermore, disordered nanoshell in black TiO2 is suggested to protect the oxygen‐deficient crystalline core, by which oxidation of Ti3+ is kinetically impeded during battery operation, leading to the enhanced electrode stability even in a highly oxidizing environment under high voltage (≈4 V).
Spiro‐Phenylpyrazole‐9,9′‐Thioxanthene Analogues as Hole‐Transporting Materials for Efficient Planar Perovskite Solar Cells
Authors: Wang Yang , Zhu Zonglong , Chueh Chu‐Chen , Jen Alex K.‐Y. , Chi Yun 
Published: June 2017

AbstractPerovskite solar cells have emerged as a promising technique for low‐cost, light weight, and highly efficient photovoltaics. However, they still largely rely on 2,2′,7,7′‐tetrakis(N,N‐di‐p‐methoxyphenylamine)‐9,9′‐spirobifluorene (Spiro‐OMeTAD) to serve as hole‐transporting materials (HTMs). Here, a series of HTMs with small molecular weight is designed, which are constructed on a spiro core involving phenylpyrazole and a second heteroaromatics, i.e., xanthene (O atom), thioxanthene (S atom), and acridine (N atom). Through varying from phenylpyrazole substituted xanthene (PPyra‐XA), thioxanthene (PPyra‐TXA), to acridine (PPyra‐ACD), their optical and electrochemical properties, hole mobilities, and the photovoltaic performance are optimized. As a consequence, PPyra‐TXA based device exhibits the highest power conversion efficiency (PCE) of 18.06%, outperforming that of Spiro‐OMeTAD (16.15%), which could be attributed to the enhancement of hole mobility exerted by the thioxanthene. In addition, the dopant‐free device shows PCE of 11.7%. These results open a new direction for designing spiro‐HTMs by simple modification of chemical structures.
Specific psychosocial exposures for workers’ mental health: A population‐based study
Authors: Navarro Albert , Utzet Mireia , Salas Sergio , Llorens Clara , Molinero‐Ruiz Emilia , Moncada Salvador 
Published: June 2017

BackgroundIn order to plan interventions it is important to obtain evidence on the relation between a health outcome and specific exposures. However, there are few studies that identify the effect of specific psychosocial work exposures on poor mental health. This is the aim of this study.MethodsPopulation‐based cross‐sectional study in Catalonia. We estimated prevalence ratios (PR) of minor psychiatric disorder associated with several psychosocial work exposures.ResultsThe items with highest PR were “Are there times when you need to be at work and at home at the same time?” (PR = 1.81), “Are you worried about a variation in your salary?” (PR = 1.77), “Is your work emotionally demanding?” (PR = 1.65) and “Are you worried about it being difficult for you to find another job if you became unemployed?” (PR = 1.51).ConclusionsThis study could be useful in order to begin planning interventions on specific psychosocial exposures to protect mental health in the workplace.