bluuebunny/crossref_metadata_2025_split huggingface dataset:
Single‐parameter model of vegetated aquatic flows
Authors: Battiato Ilenia , Rubol Simonetta 
Published: July 2014

AbstractCoupled flows through and over permeable layers occur in a variety of natural phenomena including turbulent flows over submerged vegetation. In this work, we employ a two‐domain approach to model flow through and over submerged canopies. The model, amenable of a closed‐form solution, couples the log‐law and the Darcy‐Brinkman equation, and is characterized by a novel representation of the drag force which does not rely on a parametrization through an unknown drag coefficient. This approach limits to one, i.e., the obstruction permeability, the number of free parameters. Analytical expressions for the average velocity profile through and above the canopies, volumetric flow rate, penetration length, and canopy shear layer parameter are obtained in terms of the canopy layer effective permeability. The model suggests that appropriately rescaled velocities in the canopy and surface layers follow two different scaling laws. The analytical predictions match with the experimental data collected by Ghisalberti and Nepf (2004) and Nepf et al. (2007).
Transition of effective hydraulic properties from low to high Reynolds number flow in porous media
Authors: Sivanesapillai R. , Steeb H. , Hartmaier A. 
Published: July 2014

AbstractWe numerically analyze fluid flow through porous media up to a limiting Reynolds number of . Due to inertial effects, such processes exhibit a gradual transition from laminar to turbulent flow for increasing magnitudes of Re. On the macroscopic scale, inertial transition implies nonlinearities in the relationship between the effective macroscopic pressure gradient and the filter velocity, typically accounted for in terms of the quadratic Forchheimer equation. However, various inertia‐based extensions to the linear Darcy equation have been discussed in the literature; most prominently cubic polynomials in velocity. The numerical results presented in this contribution indicate that inertial transition, as observed in the apparent permeability, hydraulic tortuosity, and interfacial drag, is inherently of sigmoidal shape. Based on this observation, we derive a novel filtration law which is consistent with Darcy's law at small Re, reproduces Forchheimer's law at large Re, and exhibits higher‐order leading terms in the weak inertia regime.
The 2011 Tohoku Tsunami observed by an array of ocean bottom electromagnetometers
Authors: Zhang Luolei , Baba Kiyoshi , Liang Pengfei , Shimizu Hisayoshi , Utada Hisashi 
Published: July 2014

AbstractA tsunami induces secondary electromagnetic (EM) fields of significant intensity as a result of Faraday's law, and these EM fields can be recorded by instruments on the seafloor. Such observations will provide parameters that are useful in understanding tsunami generation and propagation processes. As such, EM sensors can be used as a type of tsunami sensor. In the present study, we report the observation of tsunami‐induced EM signals by a small array of ocean bottom electromagnetometers consisting of four stations in the northwestern Pacific Ocean. Then, several data analysis methods are used to estimate tsunami parameters. Referring to the theoretical relation, the wave height is estimated from the observed magnetic and electric fields. Also, the propagation direction of the 2011 Tohoku Tsunami is estimated by applying analysis methods for an array and a single station.
Solar rotation effects on the Martian ionosphere
Authors: Venkateswara Rao N. , Balan N. , Patra A. K. 
Published: July 2014

AbstractWe present a detailed investigation of the solar rotation effects on the Martian high‐latitude (~63°N–81°N) ionosphere using the electron density (Ne) data measured by Mars Global Surveyor and solar XUV and EUV fluxes measured by SOHO under high (2000–2001), medium (2003), and low (2005) solar activity conditions. A fast Fourier transform spectral analysis method is used to estimate the amplitude of the rotation period in these parameters. This method clearly reveals the presence of solar rotation effects in the Martian ionospheric Ne at all altitudes (90–220 km), peak electron density (NmM2), and total electron content under the three solar activity conditions. These effects are in phase with the solar UV fluxes (corrected for the Martian orbit). The period of rotation effect (~26 days) is the same at all altitudes, though its amplitude is strongest at the ionospheric M2 peak (~135–140 km, ~3.5–6% of the mean values) and has a secondary enhancement at the M1 peak (~110–115 km). The effect of solar rotation on the M2 peak is larger during medium solar activity (2003) than during high solar activity (2000–2001). The effect, however, is absent in the ionospheric peak height (hmM2). The rotation effects on Mars are also compared with those on the Earth. Unlike at Mars, the Earth's high‐latitude ionosphere shows no clear solar rotation effect, though the effect is observed clearly at lower latitudes.
Suprathermal magnetospheric minor ions heavier than water at Saturn: Discovery of 28M+ seasonal variations
Authors: Christon S. P. , Hamilton D. C. , Mitchell D. G. , DiFabio R. D. , Krimigis S. M. 
Published: July 2014

AbstractWater group ions W+ (O+, OH+, H2O+, and H3O+), along with H+ and H2+, dominate Saturn's near‐equatorial magnetospheric suprathermal ion populations. The singly charged, minor heavy ions O2+ and 28M+ were also observed in the suprathermal energy range, but at much lower densities, having ≤10−2 the abundance of W+. From 2004 through 2013, Cassini's charge‐energy‐mass ion spectrometer has measured suprathermal 83–167 keV/e heavy ions at ~4–20 Rs (1 Saturn radius, Rs = 60,268 km). Christon et al. (2013) found apparent O2+/W+ transient and seasonal responses to variable insolation of Saturn's ring atmosphere prior to mid‐2012. A similar seasonal variation in 28M+/W+ (28M+ ~27–30 amu/e molecular minor ions) was suggested but inconclusive. Now with data from mid‐2012 through 2013, we find that both O2+ and 28M+ clearly exhibit seasonal recoveries from mid‐2012 onward. Prominent radial partial number density peaks at ~9 Rs identify W+, O2+, and 28M+ as clear ring current participants. It is presently unclear which part of Saturn's magnetosphere produces the seasonally varying 28M+ component. Dissimilar 28M+/W+ and O2+/W+ responses to a strong late 2011 solar UV burst suggest different seasonal ring‐based photolytic processes.
Ion cyclotron waves at Mars: Occurrence and wave properties
Authors: Wei H. Y. , Cowee M. M. , Russell C. T. , Leinweber H. K. 
Published: July 2014

AbstractIon cyclotron waves (ICWs) are generated during the interaction between the solar wind and the Martian exosphere in a process called ion pickup. Mars Global Surveyor (MGS) detected waves near the proton gyrofrequency, indicating pickup of the exospheric hydrogen. To analyze these waves, we first improve the zero levels of the MGS magnetic field data taken during the first aerobreaking phase and then perform a statistical study of the ICWs observed from just outside the Martian bow shock to over 14 Mars radii away. These ICW events typically last for 5 to 30 min but can occasionally last for hours. The wave power decreases slowly with distance on both the upstream and downstream sides. From the variation of wave properties with the strength of the background field, we find that there are likely still remaining offsets in at least some the data sets even after applying our calibration technique. Thus, we use the events with a strong background field to examine the wave properties that depend on an accurate determination of the field direction and strength. We find the pickup angle associated with the largest occurrence rate of ICWs to be around 45°, but neither the wave amplitude, nor wave frequency, nor wave duration appear to vary with pickup angle. Finally, we find the waves with background field strength greater than 4 nT occur on both the positive and negative electric field sides of Mars but have a larger occurrence rate on the side of Mars in the positive electric field direction (which is defined as the direction of the cross product of the magnetic field vector and solar wind flow vector).
SAR observation and numerical modeling of tidal current wakes at the East China Sea offshore wind farm
Authors: Li XiaoMing , Chi Lequan , Chen Xueen , Ren YongZheng , Lehner Susanne 
Published: July 2014

AbstractA TerraSAR‐X (TS‐X) Synthetic Aperture Radar (SAR) image acquired at the East China Sea offshore wind farm presents distinct wakes at a kilometer scale on the lee of the wind turbines. The presumption was that these wakes were caused by wind movement around turbine blades. However, wind analysis using spaceborne radiometer data, numerical weather prediction, and in situ measurements suggest that the prevailing wind direction did not align with the wakes. By analyzing measurement at the tidal gauge station and modeling of the tidal current field, these trailing wakes are interpreted to have formed when a strong tidal current impinged on the cylindrical monopiles of the wind turbines. A numerical simulation was further conducted to reproduce the tidal current wake under such conditions. Comparison of the simulated surface velocity in the wake region with the TS‐X sea surface backscatter intensity shows a similar trend. Consequently, turbulence intensity (T.I.) of the tidal current wakes over multiple piles is studied using the TS‐X observation. It is found that the T.I. has a logarithmic relation with distance. Furthermore, another case study showing wakes due to wind movement around turbine blades is presented to discuss the differences in the tidal current wakes and wind turbine wakes. The conclusion is drawn that small‐scale wakes formed by interaction of the tidal current and the turbine piles could be also imaged by SAR when certain conditions are satisfied. The study is anticipated to draw more attentions to the impacts of offshore wind foundations on local hydrodynamic field.
Estimating satellite salinity errors for assimilation of Aquarius and SMOS data into climate models
Authors: Vinogradova Nadya T. , Ponte Rui M. , Fukumori Ichiro , Wang Ou 
Published: July 2014

AbstractConstraining dynamical systems with new information from ocean measurements, including observations of sea surface salinity (SSS) from Aquarius and SMOS, requires careful consideration of data errors that are used to determine the importance of constraints in the optimization. Here such errors are derived by comparing satellite SSS observations from Aquarius and SMOS with ocean model output and in situ data. The associated data error variance maps have a complex spatial pattern, ranging from less than 0.05 in the open ocean to 1–2 (units of salinity variance) along the coasts and high latitude regions. Comparing the data‐model misfits to the data errors indicates that the Aquarius and SMOS constraints could potentially affect estimated SSS values in several ocean regions, including most tropical latitudes. In reference to the Aquarius error budget, derived errors are less than the total allocation errors for the Aquarius mission accuracy requirements in low and midlatitudes, but exceed allocation errors in high latitudes.
Impact of an extreme flood event on optical and biogeochemical properties in a subtropical coastal periurban embayment (Eastern Australia)
Authors: Oubelkheir Kadija , Ford Phillip W. , Clementson Lesley A. , Cherukuru Nagur , Fry Gary , Steven Andrew D. L. 
Published: July 2014

AbstractMajor floods impacted the city of Brisbane, eastern Australia, in January 2011, delivering large amounts of dissolved and particulate materials and nutrients into the adjacent coastal embayment, Moreton Bay. The resulting spatially resolved changes in biogeochemical and optical properties in Moreton Bay were examined 1, 2, 6, 19, and 49 weeks after the main freshwater discharge. One week postflood, total suspended matter (TSM) and chlorophyll a (TChla) concentrations varied over 1 order of magnitude throughout Moreton Bay, the particle scattering coefficient at 555 nm varied by a factor of 20, and the total absorption coefficient and colored dissolved organic matter (CDOM) absorption coefficient at 440 nm varied by a factor of 5. The largest changes in biogeochemical and optical properties observed during our study were from 1 to 2 weeks after the floods: near the Brisbane River mouth, TSM decreased by a factor of 3, CDOM by a factor of 2, while TChla increased by a factor of 3. Within a year, optical and biogeochemical properties recovered to levels similar to nonflood conditions. The strong changes in the characteristics of the particulate and dissolved material following the flood event and subsequent biological and photochemical processes led to a large spatial and temporal variability in the relative contribution of different constituents to the total absorption coefficient at 440 nm, the particle single scattering albedo, and the specific inherent optical properties. This work has significant implications for the accuracy of standard ocean color remote sensing algorithms in coastal waters during flood events.
Influences of soil moisture and vegetation on convective precipitation forecasts over the United States Great Plains
Authors: Collow Thomas W. , Robock Alan , Wu Wei 
Published: July 2014

AbstractThis study investigates the influences of soil moisture and vegetation on 30 h convective precipitation forecasts using the Weather Research and Forecasting model over the United States Great Plains with explicit treatment of convection. North American Regional Reanalysis (NARR) data were used as initial and boundary conditions. We also used an adjusted soil moisture (uniformly adding 0.10 m3/m3 over all soil layers based on NARR biases) to determine whether using a simple observationally based adjustment of soil moisture forcing would provide more accurate simulations and how the soil moisture addition would impact meteorological parameters for different vegetation types. Current and extreme (forest and barren) land covers were examined. Compared to the current vegetation cover, the complete removal of vegetation produced substantially less precipitation, while conversion to forest led to small differences in precipitation. Adding 0.10 m3/m3 to the soil moisture with the current vegetation cover lowered the near surface temperature and increased the humidity to a similar degree as using a fully forested domain with no soil moisture adjustment. However, these temperature and humidity effects on convective available potential energy and moist enthalpy nearly canceled each other out, resulting in a limited precipitation response. Although no substantial changes in precipitation forecasts were found using the adjusted soil moisture, the similarity found between temperature and humidity forecasts using the increased soil moisture and those with a forested domain highlights the sensitivity of the model to soil moisture changes, reinforcing the need for accurate soil moisture initialization in numerical weather forecasting models.
Geomagnetic storms, super‐storms, and their impacts on GPS‐based navigation systems
Authors: Astafyeva E. , Yasyukevich Yu. , Maksikov A. , Zhivetiev I. 
Published: July 2014

AbstractUsing data of GPS receivers located worldwide, we analyze the quality of GPS performance during four geomagnetic storms of different intensity: two super‐storms and two intense storms. We show that during super‐storms the density of GPS Losses‐of‐Lock (LoL) increases up to 0.25% at L1 frequency and up to 3% at L2 frequency, and up to 0.15% (at L1) and 1% (at L2) during less intense storms. Also, depending on the intensity of the storm time ionospheric disturbances, the total number of total electron content (TEC) slips can exceed from 4 to 40 times the quiet time level. Both GPS LoL and TEC slips occur during abrupt changes of SYM‐H index of geomagnetic activity, i.e., during the main phase of geomagnetic storms and during development of ionospheric storms. The main contribution in the total number of GPS LoL was found to be done by GPS sites located at low and high latitudes, whereas the area of numerous TEC slips seemed to mostly correspond to the boundary of the auroral oval, i.e., region with intensive ionospheric irregularities. Our global maps of TEC slips show where the regions with intense irregularities of electron density occur during geomagnetic storms and will let us in future predict appearance of GPS errors for geomagnetically disturbed conditions.
An unexpected prolonged coma due to a pharmacobezoar formed from Vegetamine A® tablet ingestion
Authors: Sato Chie , Kamijo Yoshito 
Published: July 2014

CaseA 49‐year‐old man ingested massive quantities of Vegetamine A® tablets that contain two anticholinergic agents in addition to phenobarbital. The patient remained in an unexpectedly prolonged coma 4 days post‐hospitalization. An acute gastroscopy revealed a pinkish‐white pharmacobezoar on the lesser curvature of the stomach, which was extracted using a net. Direct hemoperfusion and treatment with multiple‐dose activated charcoal was then initiated. Phenobarbital serum concentrations eventually decreased, resulting in complete recovery of the patient.OutcomeOn day 30, the patient was transferred to the Psychiatric Department.ConclusionAn intragastric pharmacobezoar should be suspected in patients with promoted and prolonged toxicity or if high serum concentrations of agents indicate their continuous absorption.
Genetic and phenotypic diversity of NHE6 mutations in Christianson syndrome
Authors: Pescosolido Matthew F. , Stein David M. , Schmidt Michael , El Achkar Christelle Moufawad , Sabbagh Mark , Rogg Jeffrey M. , Tantravahi Umadevi , McLean Rebecca L. , Liu Judy S. , Poduri Annapurna , Morrow Eric M. 
Published: July 2014

ObjectiveRecently, Christianson syndrome (CS) has been determined to be caused by mutations in the X‐linked Na+/H+ exchanger 6 (NHE6). We aimed to determine the diagnostic criteria and mutational spectrum for CS.MethodsTwelve independent pedigrees (14 boys, age = 4–19 years) with mutations in NHE6 were administered standardized research assessments, and mutations were characterized.ResultsThe mutational spectrum was composed of 9 single nucleotide variants, 2 indels, and 1 copy number variation deletion. All mutations were protein‐truncating or splicing mutations. We identified 2 recurrent mutations (c.1498 c>t, p.R500X; and c.1710 g>a, p.W570X). Otherwise, all mutations were unique. In our study, 7 of 12 mutations (58%) were de novo, in contrast to prior literature wherein mutations were largely inherited. We also report prominent neurological, medical, and behavioral symptoms. All CS participants were nonverbal and had intellectual disability, epilepsy, and ataxia. Many had prior diagnoses of autism and/or Angelman syndrome. Other neurologic symptoms included eye movement abnormalities (79%), postnatal microcephaly (92%), and magnetic resonance imaging evidence of cerebellar atrophy (33%). Regression was noted in 50%, with recurrent presentations involving loss of words and/or the ability to walk. Medical symptoms, particularly gastrointestinal symptoms, were common. Height and body mass index measures were below normal ranges in most participants. Behavioral symptoms included hyperkinetic behavior (100%), and a majority exhibited high pain threshold.InterpretationThis is the largest cohort of independent CS pedigrees reported. We propose diagnostic criteria for CS. CS represents a novel neurogenetic disorder with general relevance to autism, intellectual disability, Angelman syndrome, epilepsy, and regression. Ann Neurol 2014;76:581–593
Catalytic Enantioselective Carboannulation with Allylsilanes
Authors: Ball‐Jones Nicolas R. , Badillo Joseph J. , Tran Ngon T. , Franz Annaliese K. 
Published: July 2014

AbstractThe first catalytic asymmetric carboannulation with allylsilanes is presented. The enantioselective [3+2] annulation is catalyzed using a scandium(III)/indapybox complex with tetrakis‐[3,5‐bis(trifluoromethyl)phenyl]‐borate (BArF) to enhance catalytic activity and control stereoselectivity. Functionalized cyclopentanes containing a quaternary carbon center are derived from alkylidene oxindole, coumarin, and malonate substrates with high stereoselectivity. The enantioselective 1,4‐conjugate addition and enantioselective lactone formation (by trapping of the β‐silyl carbocation) is also described.
CNH2 Bond Formation Mediated by Iridium Complexes
Authors: Mena Inmaculada , Casado Miguel A. , Polo Víctor , García‐Orduña Pilar , Lahoz Fernando J. , Oro Luis A. 
Published: July 2014

AbstractIn the presence of phosphanes (PR3), the amido‐bridged trinuclear complex [{Ir(μ‐NH2)(tfbb)}3] (tfbb=tetrafluorobenzobarrelene) transforms into mononuclear discrete compounds [Ir(1,2‐η2‐4‐κ‐C12H8F4N)(PR3)3], which are the products of the CN coupling between the amido moiety and a vinylic carbon of the diolefin. An alternative synthetic approach to these species involves the reaction of the 18 e− complex [Ir(Cl)(tfbb)(PMePh2)2] with gaseous ammonia and additional phosphane. DFT studies show that both transformations occur through nucleophilic attack. In the first case the amido moiety attacks a diolefin coordinated to a neighboring molecule following a bimolecular mechanism induced by the highly basic NH2 moiety; the second pathway involves a direct nucleophilic attack of ammonia to a coordinated tfbb molecule.
Evidence of Dihydrogen Bonding of a Chiral Amine–Borane Complex in Solution by VCD Spectroscopy
Authors: Merten Christian , Berger Christopher J. , McDonald Robert , Xu Yunjie 
Published: July 2014

AbstractIR and vibrational circular dichroism (VCD) spectra of a chiral amine–borane in solution are investigated. By comparison of experimental and calculated spectra, unique VCD spectral signatures, which can be attributed to the formation of dihydrogen‐bonded dimers in solution, are identified for the first time. These VCD features are highly sensitive to the specific dihydrogen‐bonding topologies utilized by the chiral amine–borane subunits and thus provide direct structural information of these dihydrogen‐bonded species in solution. Differences in the dihydrogen binding arrangements in solution and in solid state are also revealed.
High Correlation between Oxidation Loci on Graphene Oxide
Authors: Yang Jinrong , Shi Guosheng , Tu Yusong , Fang Haiping 
Published: July 2014

AbstractRecent experiments have shown the coexistence of both large unoxidized and oxidized regions on graphene oxide (GO), but the underlying mechanism for the formation of the GO atomic structure remains unknown. Now, using density functional calculations, 52 oxidation pathways for local pyrene structures on GO were identified, and a kinetic profile for graphene oxidation with a high correlation between oxidation loci was proposed, which is different from the conventional view, which entails a random distribution of oxidation loci. The high correlation is an essential nature of graphene oxidation processes and can be attributed to three crucial effects: 1) breaking of delocalized π bonds, 2) steric hindrance, and 3) hydrogen‐bond formation. This high correlation leads to the coexistence of both large unoxidized and oxidized regions on GO. Interestingly, even in oxidized regions on GO, some small areas of sp2‐hybridized domains, similar to “islands”, can persist because of steric effects.