bluuebunny/crossref_metadata_2025_split huggingface dataset:
The water content of recurring slope lineae on Mars
Authors: Edwards Christopher S. , Piqueux Sylvain 
Published: August 2016

AbstractObservations of recurring slope lineae (RSL) from the High‐Resolution Imaging Science Experiment have been interpreted as present‐day, seasonally variable liquid water flows; however, orbital spectroscopy has not confirmed the presence of liquid H2O, only hydrated salts. Thermal Emission Imaging System (THEMIS) temperature data and a numerical heat transfer model definitively constrain the amount of water associated with RSL. Surface temperature differences between RSL‐bearing and dry RSL‐free terrains are consistent with no water associated with RSL and, based on measurement uncertainties, limit the water content of RSL to at most 0.5–3 wt %. In addition, distinct high thermal inertia regolith signatures expected with crust‐forming evaporitic salt deposits from cyclical briny water flows are not observed, indicating low water salinity (if any) and/or low enough volumes to prevent their formation. Alternatively, observed salts may be preexisting in soils at low abundances (i.e., near or below detection limits) and largely immobile. These RSL‐rich surfaces experience ~100 K diurnal temperature oscillations, possible freeze/thaw cycles and/or complete evaporation on time scales that challenge their habitability potential. The unique surface temperature measurements provided by THEMIS are consistent with a dry RSL hypothesis or at least significantly limit the water content of Martian RSL.
Mirror mode structures ahead of dipolarization front near the neutral sheet observed by Cluster
Authors: Wang G. Q. , Zhang T. L. , Volwerk M. , Schmid D. , Baumjohann W. , Nakamura R. , Pan Z. H. 
Published: August 2016

AbstractMagnetic compressional structures ahead of a dipolarization front (DF) on 30 August 2002 are investigated by using Cluster data. Our findings are as follows: (1) the structures, observed near the neutral sheet, are mainly compressional and dominant in BZ; (2) they are almost nonpropagating relative to the local ion bulk flow and their lengths are several local proton gyroradius; (3) the ion density increases when BT decreases; (4) ions are partially trapped by the structures with parallel and perpendicular velocities varying in antiphase; and (5) local conditions are favorable for excitation of the mirror instability, and we suggest that these structures are mirror mode‐like. Our findings also suggest that local conditions ahead of the DF are viable for exciting the mirror instability to generate mirror mode waves or structures.
Unraveling the excitation mechanisms of highly oblique lower band chorus waves
Authors: Li W. , Mourenas D. , Artemyev A. V. , Bortnik J. , Thorne R. M. , Kletzing C. A. , Kurth W. S. , Hospodarsky G. B. , Reeves G. D. , Funsten H. O. , Spence H. E. 
Published: August 2016

AbstractExcitation mechanisms of highly oblique, quasi‐electrostatic lower band chorus waves are investigated using Van Allen Probes observations near the equator of the Earth's magnetosphere. Linear growth rates are evaluated based on in situ, measured electron velocity distributions and plasma conditions and compared with simultaneously observed wave frequency spectra and wave normal angles. Accordingly, two distinct excitation mechanisms of highly oblique lower band chorus have been clearly identified for the first time. The first mechanism relies on cyclotron resonance with electrons possessing both a realistic temperature anisotropy at keV energies and a plateau at 100–500 eV in the parallel velocity distribution. The second mechanism corresponds to Landau resonance with a 100–500 eV beam. In both cases, a small low‐energy beam‐like component is necessary for suppressing an otherwise dominating Landau damping. Our new findings suggest that small variations in the electron distribution could have important impacts on energetic electron dynamics.
Distinguishing and correlating deposits from large ignimbrite eruptions using paleomagnetism: The Cougar Point Tuffs (mid‐Miocene), southern Snake River Plain, Idaho, USA
Authors: Finn David R. , Coe Robert S. , Brown Ethan , Branney Michael , Reichow Marc , Knott Thomas , Storey Michael , Bonnichsen Bill 
Published: August 2016

AbstractIn this paper, we present paleomagnetic, geochemical, mineralogical, and geochronologic evidence for correlation of the mid‐Miocene Cougar Point Tuff (CPT) in southwest Snake River Plain (SRP) of Idaho. The new stratigraphy presented here significantly reduces the frequency and increases the scale of known SRP ignimbrite eruptions. The CPT section exposed at the Black Rock Escarpment along the Bruneau River has been correlated eastward to the Brown's Bench escarpment (six common eruption units) and Cassia Mountains (three common eruption units) regions of southern Idaho. The CPT records an unusual pattern of geomagnetic field directions that provides the basis for robust stratigraphic correlations. Paleomagnetic characterization of eruption units based on geomagnetic field variation has a resolution on the order of a few centuries, providing a strong test of whether two deposits could have been emplaced from the same eruption or from temporally separate events. To obtain reliable paleomagnetic directions, the anisotropy of anhysteretic remanence was measured to correct for magnetic anisotropy, and an efficient new method was used to remove gyroremanence acquired during alternating field demagnetization.
How heterogeneous coseismic slip affects regional probabilistic tsunami hazard assessment: A case study in the South China Sea
Authors: Li Linlin , Switzer Adam D. , Chan Chung‐Han , Wang Yu , Weiss Robert , Qiu Qiang 
Published: August 2016

AbstractRupture complexity, typically in the form of heterogeneous slip distribution pattern, significantly affects the local tsunami wave field. However, the effect of rupture complexity is not commonly considered in any form of tsunami hazard assessment. Taking rupture complexity into account significantly increases the computational load, particularly in regional‐scaled probabilistic tsunami hazard assessments (PTHAs) that usually require a large number of simulations based on synthetic scenarios. In this study, we investigate how the heterogeneous slip distribution affects the regional‐scaled PTHA by taking the South China Sea (SCS) as an example. By doing this, we update PTHA for the SCS by incorporating the best available information of seismic tsunamigenic sources along the Manila megathrust. We integrate a stochastic source model into a Monte Carlo‐type simulation, in which a broad range of slip distribution patterns is generated for large numbers of synthetic earthquake events. Green's function technique is employed to efficiently calculate the nearshore tsunami wave amplitude along the SCS coastlines. Our result suggests that for a relatively small and confined region like the SCS, the commonly used approach based on the uniform slip model significantly underestimates tsunami hazard not only in the near‐source region like west Luzon, as expected, but also in the relative far field, such as south China and central Vietnam. Additionally, our sensitivity test of the patch size effects suggests that large patch size is unable to adequately resolve the details of heterogeneous seafloor deformation, and such approaches considerably underestimate the potential tsunami hazard for the SCS coasts.
Avulsion cycles and their stratigraphic signature on an experimental backwater‐controlled delta
Authors: Ganti Vamsi , Chadwick Austin J. , Hassenruck‐Gudipati Hima J. , Lamb Michael P. 
Published: August 2016

AbstractRiver deltas grow in large part through repeated cycles of lobe construction and channel avulsion. Understanding avulsion cycles is important for coastal restoration and ecology, land management, and flood hazard mitigation. Emerging theories suggest that river avulsions on lowland deltas are controlled by backwater hydrodynamics; however, our knowledge of backwater‐controlled avulsion cycles is limited. Here we present results from an experimental delta that evolved under persistent backwater hydrodynamics achieved through variable flood discharges, shallow bed slopes, and subcritical flows. The experimental avulsion cycles consisted of an initial phase of avulsion setup, an avulsion trigger, selection of a new flow path, and abandonment of the parent channel. Avulsions were triggered during the largest floods (78% of avulsions) after the channel was filled by a fraction (0.3 ± 0.13) of its characteristic flow depth at the avulsion site, which occurred in the upstream part of the backwater zone. The new flow path following avulsion was consistently one of the shortest paths to the shoreline, and channel abandonment occurred through temporal decline in water flow and sediment delivery to the parent channel. Experimental synthetic stratigraphy indicates that bed thicknesses were maximum at the avulsion sites, consistent with our morphologic measurements of avulsion setup and the idea that there is a record of avulsion locations and thresholds in sedimentary rocks. Finally, we discuss the implications of our findings within the context of sustainable management of deltas, their stratigraphic record, and predicting avulsions on deltas.
Dual Oxygen and Tungsten Vacancies on a WO3 Photoanode for Enhanced Water Oxidation
Authors: Ma Ming , Zhang Kan , Li Ping , Jung Myung Sun , Jeong Myung Jin , Park Jong Hyeok 
Published: August 2016

AbstractAlleviating charge recombination at the electrode/electrolyte interface by introducing an overlayer is considered an efficient approach to improve photoelectrochemical (PEC) water oxidation. A WO3 overlayer with dual oxygen and tungsten vacancies was prepared by using a solution‐based reducing agent, LEDA (lithium dissolved in ethylenediamine), which improved the PEC performance of the mesoporous WO3 photoanode dramatically. In comparison to the pristine samples, the interconnected WO3 nanoparticles surrounded by a 2–2.5 nm thick overlayer exhibited a photocurrent density approximately 2.4 times higher and a marked cathodic shift of the onset potential, which is mainly attributed to the facilitative effect on interface charge transfer and the improved conductivity by enhanced charge carrier density. This simple and effective strategy may provide a new path to improve the PEC performance of other photoanodes.
Iridium‐Catalyzed Regio‐ and Enantioselective Allylic Substitution of Trisubstituted Allylic Electrophiles
Authors: Chen Ming , Hartwig John F. 
Published: August 2016

AbstractThe first Ir‐catalyzed enantioselective allylation of trisubstituted allylic electrophiles has been developed. Through modification of the leaving group of allylic electrophiles, we found that trisubstituted allylic phosphates are suitable electrophiles for asymmetric allylation. The reaction of allylic phosphates with enol silanes derived from dioxinones gave allylated products in good yields with high enantioselectivities.
Organic Reactions in Microdroplets: Reaction Acceleration Revealed by Mass Spectrometry
Authors: Yan Xin , Bain Ryan M. , Cooks R. Graham 
Published: August 2016

AbstractThe striking finding that reaction acceleration occurs in confined‐volume solutions sets up an apparent conundrum: Microdroplets formed by spray ionization can be used to monitor the course of bulk‐phase reactions and also to accelerate reactions between the reagents in such a reaction. This Minireview introduces droplet and thin‐film acceleration phenomena and summarizes recent methods applied to study accelerated reactions in confined‐volume, high‐surface‐area solutions. Conditions that dictate either simple monitoring or acceleration are reconciled in the occurrence of discontinuous and complete desolvation as the endpoint of droplet evolution. The contrasting features of microdroplet and bulk‐solution reactions are described together with possible mechanisms that drive reaction acceleration in microdroplets. Current applications of droplet microreactors are noted as is reaction acceleration in confined volumes and possible future scale‐up.
A PCP Pincer Ligand for Coordination Polymers with Versatile Chemical Reactivity: Selective Activation of CO2 Gas over CO Gas in the Solid State
Authors: He Junpeng , Waggoner Nolan W. , Dunning Samuel G. , Steiner Alexander , Lynch Vincent M. , Humphrey Simon M. 
Published: August 2016

AbstractA tetra(carboxylated) PCP pincer ligand has been synthesized as a building block for porous coordination polymers (PCPs). The air‐ and moisture‐stable PCP metalloligands are rigid tetratopic linkers that are geometrically akin to ligands used in the synthesis of robust metal–organic frameworks (MOFs). Here, the design principle is demonstrated by cyclometalation with PdIICl and subsequent use of the metalloligand to prepare a crystalline 3D MOF by direct reaction with CoII ions and structural resolution by single crystal X‐ray diffraction. The Pd−Cl groups inside the pores are accessible to post‐synthetic modifications that facilitate chemical reactions previously unobserved in MOFs: a Pd−CH3 activated material undergoes rapid insertion of CO2 gas to give Pd−OC(O)CH3 at 1 atm and 298 K. However, since the material is highly selective for the adsorption of CO2 over CO, a Pd−N3 modified version resists CO insertion under the same conditions.
Synthesis and characterization of polyimide/modified mCOC composites
Authors: Cheng Yao-Yi , Hsiao Hsin-Min , Li Zong-Xuan , Ho Ming-Jaan , Hsu Mao-Feng , Hsiang Shou‐Jui 
Published: August 2016

ABSTRACTTwo types of monomers, 4,4′‐(hexafluoroisopropylidene) diphthalic anhydride and 4,4′‐oxydianiline, were employed to synthesize poly(amic acid) (PAA) as a precursor of polyimide (PI). Through the addition of modified metallocene cyclic olefin copolymer (mCOC), PAA/mCOC composites were formed. PI/mCOC composites were obtained through a blade coating and multistep thermal curing process. The structure of the prepared PI/mCOC composites was characterized through Fourier transform infrared spectrometry. The results showed that the copolymerization of PAA and modified mCOC improved thethermal stability and hydrophobic and electrical properties of the PI/mCOC composites. The formation of a network structure between PI and modified mCOC considerably reduced the mobility of PI molecules, thereby improving the glass transition temperature and thermal properties of the composite. The thermal and hydrophobic properties were improved by increasing the mCOC grafting ratio. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 44144.
Functionalization of carbon nanotubes with (3‐glycidyloxypropyl)‐trimethoxysilane: Effect of wrapping on epoxy matrix nanocomposites
Authors: Hoepfner Jean Carlos , Pezzin Sérgio Henrique 
Published: August 2016

ABSTRACTIn this work, multiwalled carbon nanotubes (MWCNT), after previous oxidation, are functionalized with excess (3‐glycidyloxypropyl)trimethoxysilane (GLYMO) and used as reinforcement in epoxy matrix nanocomposites. Infrared, Raman, and energy‐dispersive X‐ray spectroscopies confirm the silanization of the MWCNT, while transmission electron microscopy images show that oxidized nanotubes presented less entanglement than pristine and silanized MWCNT. Thickening of the nanotubes is also observed after silanization, suggesting that the MWCNT are wrapped by siloxane chains. Field‐emission scanning electron microscopy reveals that oxidized nanotubes are better dispersed in the matrix, providing nanocomposites with better mechanical properties than those reinforced with pristine and silanized MWCNT. On the other hand, the glass transition temperature of the nanocomposite with 0.05 wt % MWCNT‐GLYMO increased by 14 °C compared to the neat epoxy resin, suggesting a strong matrix–nanotube adhesion. The functionalization of nanotubes using an excess amount of silane can thus favor the formation of an organosiloxane coating on the MWCNT, preventing its dispersion and contributing to poor mechanical properties of epoxy nanocomposites. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 44245.
Starch foam material performance prediction based on a radial basis function artificial neural network trained by bare‐bones particle swarm optimization with an adaptive disturbance factor
Authors: Xia Ruting , Huang Xingyuan , Li Mengshan 
Published: August 2016

ABSTRACTA novel model based on a radial basis artificial neural network and bare‐bones particle swarm optimization tuned with adaptive disturbance factor for predicting the performances of starch‐based foam materials was established. The ethylene–vinyl acetate/starch mass ratio, glycerin content, and NaHCO3 content were used as the input variables, whereas the tensile strength and rebound rate were taken as the output variables of the model. The prediction results show that model predictions were in great accordance with the experimental values. The root mean square error of prediction and the correlation coefficients were 0.0256 and 0.9873; this indicated the good performance of the model. The model predicted that the tensile strength of the starch‐based foam materials would decrease slowly with increasing glycerin content and showed a V‐shaped variation with increasing NaHCO3 content. The rebound rate increased with increasing glycerin content and presented an inverted V‐shaped variation with increasing NaHCO3 content. The predicted results were consistent with the experimental results. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 44252.
Production of polyvinylpyrrolidone/chiral diacid modified nanocrystalline Mg‐substituted fluorapatite nanocomposites: Morphological and thermal characterization
Authors: Mallakpour Shadpour , Khani Marziyeh , Mallakpour Fereshteh , Fathi Mohammadhossein 
Published: August 2016

ABSTRACTThe main objective of this work was the production of novel polyvinylpyrrolidone/diacid modified Mg‐substituted fluorapatite (DM‐MFA) nanocomposites (NC)s, by sonication process. Mg‐substituted fluorapatite (MFA) powders with a chemical composition of Ca9.5Mg0.5(PO4)6F2 were prepared by mechanical alloying technique. Initially, surface of MFA was modified by bioactive chiral diacid monomer, N‐trimellitylimido‐l‐leucine as a coupling agent to form DM‐MFA nanoparticles. DM‐MFA NPs were utilized as a filler, to give the NCs with potential bioactivity. Examination of transmission electron microscopy (TEM), and field emission scanning electron microscopy (FE‐SEM) microphotographs displayed that, there is no aggregation of a large quantity of particles. The above NCs showed rather improved thermal stability compared with pure polymer. The improvement of thermal behavior was related to the uniform and good dispersion of DM‐MFA in the polymer matrix as well as the strong hydrogen bonding between CO of PVP and OH of DM‐MFA. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 44254.
The Braincase and Neurosensory Anatomy of an Early Jurassic Marine Crocodylomorph: Implications for Crocodylian Sinus Evolution and Sensory Transitions
Authors: Brusatte Stephen L. , Muir Amy , Young Mark T. , Walsh Stig , Steel Lorna , Witmer Lawrence M. 
Published: August 2016

ABSTRACTModern crocodylians are a morphologically conservative group, but extinct relatives (crocodylomorphs) experimented with a wide range of diets, behaviors, and body sizes. Among the most unusual of these fossil groups is the thalattosuchians, an assemblage of marine‐dwellers that transitioned from semiaquatic species (teleosaurids and kin) into purely open‐ocean forms (metriorhynchids) during the Jurassic and Cretaceous Periods (ca 191–125 million years ago). Thalattosuchians can give insight into the origin of modern crocodylian morphologies and how anatomy and behavior change during a major evolutionary transition into a new habitat. Little is known, however, about their brains, sensory systems, cranial sinuses, and vasculature. We here describe the endocranial anatomy of a well‐preserved specimen of the Jurassic semiaquatic teleosaurid Steneosaurus cf. gracilirostris using X‐ray micro‐CT. We find that this teleosaurid still had an ear well attuned to hear on land, but had developed large internal carotid and orbital arteries that likely supplied salt glands, previously thought to be present in only the fully pelagic metriorhynchids. There is no great gulf in endocranial anatomy between this teleosaurid and the metriorhynchids, and some of the features that later permitted metriorhynchids to invade the oceanic realm were apparently first developed in semiaquatic taxa. Compared to modern crocodylians, Steneosaurus cf. gracilirostris has a more limited set of pharyngotympanic sinuses, but it is unclear whether this relates to its aquatic habitat or represents the primitive condition of crocodylomorphs that was later elaborated. Anat Rec, 299:1511–1530, 2016. © 2016 Wiley Periodicals, Inc.
Fixed‐route taxi system: route network design and fleet size minimization problems
Authors: Babaei Mohsen , Schmöcker Jan‐Dirk , Khademi Navid , Ghaffari Ahmad‐Reza , Naderan Ali 
Published: August 2016

SummaryThis paper introduces the taxi route network design problem (TXRNDP) for a fixed‐route taxi service operating in Iran and, in similar form, in various other developing countries. The service operates fairly similar to regular transit services in that vehicles are only permitted to follow a certain predetermined route on the network. The service is provided with small size vehicles and main features are that vehicles only depart if full and that there are no intermediate boarding stops. In Iran the service attracts a high modal share but requires better coordination which is the main motivation for the present study. We develop a mathematical programming model to minimize the total travel time experienced by passengers while constraining the number of taxi lines, the trip transfer ratio and the length of taxi lines. A number of assumptions are introduced in order to allow finding an exact rather than heuristic solution. We further develop a linear programming solution to minimize the number of taxis required to serve the previously found fixed‐route taxi network. Results of a case study with the city of Zanjan, Iran, illustrate the resulting taxi flows and suggest the capability of the proposed model to reduce the total travel time, the total waiting time and the number of taxi lines compared to the current taxi operation. Copyright © 2016 John Wiley & Sons, Ltd.
Stem cells for spinal cord injury: Strategies to inform differentiation and transplantation
Authors: Iyer Nisha R. , Wilems Thomas S. , Sakiyama‐Elbert Shelly E. 
Published: August 2016

ABSTRACTThe complex pathology of spinal cord injury (SCI), involving a cascade of secondary events and the formation of inhibitory barriers, hampers regeneration across the lesion site and often results in irreversible loss of motor function. The limited regenerative capacity of endogenous cells after SCI has led to a focus on the development of cell therapies that can confer both neuroprotective and neuroregenerative benefits. Stem cells have emerged as a candidate cell source because of their ability to self‐renew and differentiate into a multitude of specialized cell types. While ethical and safety concerns impeded the use of stem cells in the past, advances in isolation and differentiation methods have largely mitigated these issues. A confluence of work in stem cell biology, genetics, and developmental neurobiology has informed the directed differentiation of specific spinal cell types. After transplantation, these stem cell‐derived populations can replace lost cells, provide trophic support, remyelinate surviving axons, and form relay circuits that contribute to functional recovery. Further refinement of stem cell differentiation and transplantation methods, including combinatorial strategies that involve biomaterial scaffolds and drug delivery, is critical as stem cell‐based treatments enter clinical trials. Biotechnol. Bioeng. 2017;114: 245–259. © 2016 Wiley Periodicals, Inc.