bluuebunny/crossref_metadata_2025 huggingface dataset:
Overlap statistics of shallow boundary layer clouds: Comparing ground‐based observations with large‐eddy simulations
Authors: Corbetta G. , Orlandi E. , Heus T. , Neggers R. , Crewell S.
Published: August 2015

High‐resolution ground‐based measurements are used to assess the realism of fine‐scale numerical simulations of shallow cumulus cloud fields. The overlap statistics of cumuli as produced by large‐eddy simulations (LES) are confronted with Cloudnet data sets at the Jülich Observatory for Cloud Evolution. The Cloudnet pixel is small enough to detect cumuliform cloud overlap. Cloud fraction masks are derived for five different cases, using gridded time‐height data sets at various temporal and vertical resolutions. The overlap ratio (R), i.e., the ratio between cloud fraction by volume and by area, is studied as a function of the vertical resolution. Good agreement is found between R derived from observations and simulations. An inverse linear function is found to best describe the observed overlap behavior, confirming previous LES results. Simulated and observed decorrelation lengths are smaller (∼300 m) than previously reported (>1 km). A similar diurnal variation in the overlap efficiency is found in observations and simulations.
Lightning leader altitude progression in terrestrial gamma‐ray flashes
Authors: Cummer Steven A. , Lyu Fanchao , Briggs Michael S. , Fitzpatrick Gerard , Roberts Oliver J. , Dwyer Joseph R.
Published: August 2015

Radio emissions continue to provide insight into the production of terrestrial gamma ray flashes (TGFs) by thunderstorms, including the critical question of the conditions under which they are generated. We have identified several TGF‐associated lightning radio emissions in which the altitudes of in‐cloud lightning leader pulses that precede and follow the TGF can be measured. We combine these with high absolute timing accuracy TGF observations from the Fermi satellite to determine the development of the lightning channel before, during, and after the TGF production. All of these TGFs were produced several milliseconds after the leader had initiated and when the leaders reached 1–2 km in length. After the TGFs, the leaders all continued to ascend for several more kilometers with no dramatic change in their characteristics, although they all exhibited high average velocities of 0.8–1.0 × 106 m/s. Implications in the context of TGF models are discussed. These results paint the first clear picture of the lightning processes that occur before, during, and after TGF production.
Ross ice shelf vibrations
Authors: Bromirski P. D. , Diez A. , Gerstoft P. , Stephen R. A. , Bolmer T. , Wiens D. A. , Aster R. C. , Nyblade A.
Published: August 2015

Broadband seismic stations were deployed across the Ross Ice Shelf (RIS) in November 2014 to study ocean gravity wave‐induced vibrations. Initial data from three stations 100 km from the RIS front and within 10 km of each other show both dispersed infragravity (IG) wave and ocean swell‐generated signals resulting from waves that originate in the North Pacific. Spectral levels from 0.001 to 10 Hz have the highest accelerations in the IG band (0.0025–0.03 Hz). Polarization analyses indicate complex frequency‐dependent particle motions, with energy in several frequency bands having distinctly different propagation characteristics. The dominant IG band signals exhibit predominantly horizontal propagation from the north. Particle motion analyses indicate retrograde elliptical particle motions in the IG band, consistent with these signals propagating as Rayleigh‐Lamb (flexural) waves in the ice shelf/water cavity system that are excited by ocean wave interactions nearer the shelf front.
TES observations of the interannual variability of PAN over Northern Eurasia and the relationship to springtime fires
Authors: Zhu Liye , Fischer Emily V. , Payne Vivienne H. , Worden John R. , Jiang Zhe
Published: August 2015

Peroxyacetyl nitrate (PAN) plays an important role in atmospheric chemistry through its impact on remote oxidant and nitrogen budgets. PAN is formed rapidly in boreal fire plumes through the oxidation of short‐lived volatile organic compounds in the presence of nitrogen oxide radicals. Here we present new satellite observations of PAN from the Tropospheric Emission Spectrometer (TES) over northern Eurasia for April 2006–2010. We observe large interannual variability in TES PAN observations, and we show that fires are one source of this variability using (1) Moderate Resolution Imaging Spectroradiometer Mean Fire Radiative Power observations and (2) Hybrid Single‐Particle Lagrangian Integrated Trajectory backward trajectories. We also show that cold springtime temperatures and enhanced vertical mixing in the lower free troposphere over northeastern Eurasia likely played a role in the detection of PAN from TES in April 2006 in this region.
Atmospheric response to the North Pacific enabled by daily sea surface temperature variability
Authors: Zhou Guidi , Latif Mojib , Greatbatch Richard J. , Park Wonsun
Published: August 2015

Ocean‐atmosphere interactions play a key role in climate variability on a wide range of timescales from seasonal to decadal and longer. The extratropical oceans are thought to exert noticeable feedbacks on the atmosphere especially on decadal and longer timescales, yet the large‐scale atmospheric response to anomalous extratropical sea surface temperature (SST) is still under debate. Here we show, by means of dedicated high‐resolution atmospheric model experiments, that sufficient daily variability in the extratropical background SST needs to be resolved to force a statistically significant large‐scale atmospheric response to decadal North Pacific SST anomalies associated with the Pacific Decadal Oscillation, which is consistent with observations. The large‐scale response is mediated by atmospheric eddies. This implies that daily extratropical SST fluctuations must be simulated by the ocean components and resolved by the atmospheric components of global climate models to enable realistic simulation of decadal North Pacific sector climate variability.
Dynamical and thermodynamical modulations on future changes of landfalling atmospheric rivers over western North America
Authors: Gao Yang , Lu Jian , Leung L. Ruby , Yang Qing , Hagos Samson , Qian Yun
Published: August 2015

This study examines future changes of landfalling atmospheric rivers (ARs) over western North America using outputs from the Coupled Model Intercomparison Project Phase 5 (CMIP5). The result reveals a strikingly large increase of AR days by the end of the 21st century in the RCP8.5 scenario, with fractional increases between 50% and 600%, depending on the seasons and landfall locations. These increases are predominantly controlled by the super‐Clausius‐Clapeyron rate of increase of atmospheric water vapor with warming, while changes of winds that transport moisture in the ARs, or dynamical effect, mostly counter the thermodynamical effect of increasing water vapor, limiting the increase of AR events in the future. The consistent negative effect of wind changes on AR days during spring and fall can be linked to the robust poleward shift of the subtropical jet in the North Pacific basin.
Magnetic meridional winds in the thermosphere obtained from Global Assimilation of Ionospheric Measurements (GAIM) model
Authors: Lomidze Levan , Scherliess Ludger , Schunk Robert W.
Published: August 2015

Thermospheric neutral winds play an important part in the dynamics of ionospheric plasma and represent one of the key inputs for ionospheric physics‐based models. Yet wind measurements are scarce and generally lack global coverage and continuity. To help mitigate this shortcoming, a data assimilation model was used to estimate neutral winds in the low‐ and middle‐latitude thermosphere. Seasonal global maps of NmF2 and hmF2 were generated from Constellation Observing System for Meteorology, Ionosphere, and Climate radio occultation measurements for geomagnetically quiet and low solar flux conditions. The maps were assimilated into the Utah State University Global Assimilation of Ionospheric Measurements–Full Physics (GAIM‐FP) model. GAIM‐FP, which uses the physics‐based ionosphere‐plasmasphere model (IPM) and employs an ensemble Kalman filter technique, significantly improved the agreement between the modeled and measured NmF2 and hmF2 globally compared to the IPM. Global quiet time magnetic meridional winds were derived for December and June solstices and March equinox. The morphology of the derived winds was analyzed and validated by comparing with ground‐based measurements and with wind values from the empirical horizontal wind model. GAIM‐FP‐estimated winds were shown to be in good agreement with the wind observations. Furthermore, the sensitivity of the derived winds to uncertain parameters, including the O+‐O collision frequency, neutral composition, number of radio occultations, and data errors, was investigated. The uncertainties were found to have only small effects on the derived winds. The results of this work indicate that thermospheric wind estimation from GAIM‐FP is a valuable tool for wind specification over regions where limited or no wind measurements exist.
Cusp dynamics under northward IMF using three‐dimensional global particle‐in‐cell simulations
Authors: Cai D. , Esmaeili A. , Lembège B. , Nishikawa K‐I
Published: August 2015

The interaction of the solar wind with the terrestrial magnetosphere is analyzed with the help of three‐dimensional (3‐D) global, full‐electromagnetic particle‐in‐cell (PIC) simulations, in the configuration where the interplanetary magnetic field (IMF) is steadily northward. The present study is mainly focused on the cusp region and associated particle momenta dynamics. Within the present context and to the best of our knowledge, this work represents the first numerical simulation for analyzing the cusp dynamics using a fully self‐consistent 3‐D kinetic and electromagnetic approach. The main goals of the study are the following: (i) to retrieve the main known features of the cusp to validate the use of 3‐D PIC “global” simulations, (ii) to compare with previous results obtained with 3‐D MHD simulations, (iii) to create an updated global view of the cusp based on use of 3‐D PIC simulation, which cannot be obtained from a MHD approach, and (iv) to compare with statistical results from the Cluster mission. In particular, the stagnant exterior cusp (SEC) identified in previous statistical analysis of experimental data is retrieved, and it is possible to more precisely define the edges of the SEC region. In addition, we will focus on cusp features recently observed by the Cluster mission, for example, the Alfvén Transition Layer or ATL and on the features not reproduced by either MHD or the hybrid approach, which have been used to characterize the outer edges of the cusp more clearly.
Physics‐based reconstruction of the 3‐D density distribution in the entire quiet time plasmasphere from measurements along a single pass of an orbiter
Authors: Kotova G. A. , Verigin M. I. , Bezrukikh V. V.
Published: August 2015

The data base of the Alpha‐3/Interball‐1 measurements was used for semiempirical 3‐D modeling of plasma distribution inside the plasmasphere for quiet (stationary) geomagnetic conditions. A 2‐D model describing the density distribution in the meridional plane is based on equations of the plasma distribution in the plasmasphere for the cases of thermal equilibrium and collisionless initial partial filling of plasmaspheric shells. This 2‐D model is then expanded into a 3‐D one using simple equations for the shape of the plasmapause and density behavior in the equatorial plane along the convection streamline. The model has six free parameters with clear physical meaning. This modeling approach can be applied for extrapolation of data from magnetospheric satellites with very different orbits into the entire plasmasphere.
Chorus intensity modulation driven by time‐varying field‐aligned low‐energy plasma
Authors: Nishimura Y. , Bortnik J. , Li W. , Liang J. , Thorne R. M. , Angelopoulos V. , Le Contel O. , Auster U. , Bonnell J. W.
Published: August 2015

Recent studies have shown that chorus waves are responsible for scattering and precipitating the energetic electrons that drive the pulsating aurora. While some of the chorus intensity modulation events are correlated with <~100 eV electron density modulation, most of the chorus intensity modulation events in the postmidnight sector occur without apparent density changes. Although it is generally difficult to measure evolution of low‐energy (<~20 eV) electron fluxes due to constraints imposed by the spacecraft potential and electrostatic analyzer (ESA) energy range limit, we identified using Time History of Events and Macroscale Interactions during Substorms (THEMIS) satellite data that low‐energy ions of ~100 eV show density modulation that is correlated with chorus intensity modulation. Those low‐energy ions and electrons are field‐aligned with major peaks in 0° (for northern hemisphere winter event) and 180° (for northern hemisphere summer event) pitch angle, indicating that outflowing plasma from the sunlit hemisphere is the source of the low‐energy plasma density modulation near the equator. Plasma sheet plasma density, and ambient electric and magnetic fields do not show modulations that are correlated with the chorus intensity modulation. Assuming charge neutrality, the low‐energy ions can be used to represent cold plasma density in wave growth rate calculations, and the enhancements of the low‐energy plasma density are found to contribute most effectively to chorus linear growth rates. These results suggest that chorus intensity modulation is driven by a feedback process where outflowing plasma due to energetic electron precipitation increases the equatorial density that drives further electron precipitation.
Constraining the pickup ion abundance and temperature through the multifluid reconstruction of the Voyager 2 termination shock crossing
Authors: Zieger Bertalan , Opher Merav , Tóth Gábor , Decker Robert B. , Richardson John D.
Published: August 2015

Voyager 2 observations revealed that the hot solar wind ions (the so‐called pickup ions) play a dominant role in the thermodynamics of the termination shock and the heliosheath. The number density and temperature of this hot population, however, have remained unknown, since the plasma instrument on board Voyager 2 can only detect the colder thermal ion component. Here we show that due to the multifluid nature of the plasma, the fast magnetosonic mode splits into a low‐frequency fast mode and a high‐frequency fast mode. The coupling between the two fast modes results in a quasi‐stationary nonlinear wave mode, the “oscilliton,” which creates a large‐amplitude trailing wave train downstream of the thermal ion shock. By fitting multifluid shock wave solutions to the shock structure observed by Voyager 2, we are able to constrain both the abundance and the temperature of the undetected pickup ions. In our three‐fluid model, we take into account the nonnegligible partial pressure of suprathermal energetic electrons (0.022–1.5 MeV) observed by the Low‐Energy Charged Particle Experiment instrument on board Voyager 2. The best fitting simulation suggests a pickup ion abundance of 20 ± 3%, an upstream pickup ion temperature of 13.4 ± 2 MK, and a hot electron population with an apparent temperature of ~0.83 MK. We conclude that the actual shock transition is a subcritical dispersive shock wave with low Mach number and high plasma β.
Frictional behavior of talc‐calcite mixtures
Authors: Giorgetti C. , Carpenter B. M. , Collettini C.
Published: August 2015

Faults involving phyllosilicates appear weak when compared to the laboratory‐derived strength of most crustal rocks. Among phyllosilicates, talc, with very low friction, is one of the weakest minerals involved in various tectonic settings. As the presence of talc has been recently documented in carbonate faults, we performed laboratory friction experiments to better constrain how various amounts of talc could alter these fault's frictional properties. We used a biaxial apparatus to systematically shear different mixtures of talc and calcite as powdered gouge at room temperature, normal stresses up to 50 MPa and under different pore fluid saturated conditions, i.e., CaCO3‐equilibrated water and silicone oil. We performed slide‐hold‐slide tests, 1–3000 s, to measure the amount of frictional healing and velocity‐stepping tests, 0.1–1000 µm/s, to evaluate frictional stability. We then analyzed microstructures developed during our experiments. Our results show that with the addition of 20% talc the calcite gouge undergoes a 70% reduction in steady state frictional strength, a complete reduction of frictional healing and a transition from velocity‐weakening to velocity‐strengthening behavior. Microstructural analysis shows that with increasing talc content, deformation mechanisms evolve from distributed cataclastic flow of the granular calcite to localized sliding along talc‐rich shear planes, resulting in a fully interconnected network of talc lamellae from 20% talc onward. Our observations indicate that in faults where talc and calcite are present, a low concentration of talc is enough to strongly modify the gouge's frictional properties and specifically to weaken the fault, reduce its ability to sustain future stress drops, and stabilize slip.
Momentum flux estimates accompanying multiscale gravity waves over Mount Cook, New Zealand, on 13 July 2014 during the DEEPWAVE campaign
Authors: Bossert Katrina , Fritts David C. , Pautet Pierre‐Dominique , Williams Bifford P. , Taylor Michael J. , Kaifler Bernd , Dörnbrack Andreas , Reid Iain M. , Murphy Damian J. , Spargo Andrew J. , MacKinnon Andrew D.
Published: August 2015

Observations performed with a Rayleigh lidar and an Advanced Mesosphere Temperature Mapper aboard the National Science Foundation/National Center for Atmospheric Research Gulfstream V research aircraft on 13 July 2014 during the Deep Propagating Gravity Wave Experiment (DEEPWAVE) measurement program revealed a large‐amplitude, multiscale gravity wave (GW) environment extending from ~20 to 90 km on flight tracks over Mount Cook, New Zealand. Data from four successive flight tracks are employed here to assess the characteristics and variability of the larger‐ and smaller‐scale GWs, including their spatial scales, amplitudes, phase speeds, and momentum fluxes. On each flight, a large‐scale mountain wave (MW) having a horizontal wavelength ~200–300 km was observed. Smaller‐scale GWs over the island appeared to correlate within the warmer phase of this large‐scale MW. This analysis reveals that momentum fluxes accompanying small‐scale MWs and propagating GWs significantly exceed those of the large‐scale MW and the mean values typical for these altitudes, with maxima for the various small‐scale events in the range ~20–105 m2 s−2.
Transboundary transport and deposition of Hg emission from springtime biomass burning in the Indo‐China Peninsula
Authors: Wang Xun , Zhang Hui , Lin Che‐Jen , Fu Xuewu , Zhang Yiping , Feng Xinbin
Published: August 2015

Biomass burning from the Indo‐China Peninsula region is an important source of atmospheric mercury (Hg). We isolated 18 unique transport events over 2 years using observations of Hg and CO at a high‐altitude background site in southwestern China (Mount Ailao Observatory Station) to assess the transport and impact of Hg emissions from biomass burning. The quantity of Hg emission and the source regions were determined using ΔTGM/ΔCO slopes coupled with backward trajectory analysis and CO emission inventories. The slopes of ΔTGM/ΔCO appeared to be a useful chemical indicator for source identification. Industrial emission sources exhibited slopes in the range of 5.1–61.0 × 10−7 (parts per trillion by volume, pptv/pptv), in contrast to a slope of 2.0–6.0 × 10−7 for typical biomass burning. Transboundary transport of Hg from biomass burning led to episodically elevated atmospheric Hg concentrations during springtime. Hg emissions from biomass burning in the Indo‐China Peninsula region from 2001 to 2008 were estimated to be 11.4 ± 2.1 Mg yr−1, equivalent to 40% of annual anthropogenic emissions in the region. In addition, Hg emissions from biomass burning contained a substantial fraction of particulate bound Hg (PBM). Assuming that PBM readily deposits locally (within 50 km), the local Hg deposition caused by the PBM was estimated to be 2.2 ± 0.4 Mg yr−1, up to 1 order of magnitude higher than the PBM deposition caused by anthropogenic emissions during springtime in the region. The strong springtime emissions potentially pose a threat to the ecosystems of the Indo‐China Peninsula and southwest China.
Satellite detection, long‐range transport, and air quality impacts of volcanic sulfur dioxide from the 2014–2015 flood lava eruption at Bárðarbunga (Iceland)
Authors: Schmidt Anja , Leadbetter Susan , Theys Nicolas , Carboni Elisa , Witham Claire S. , Stevenson John A. , Birch Cathryn E. , Thordarson Thorvaldur , Turnock Steven , Barsotti Sara , Delaney Lin , Feng Wuhu , Grainger Roy G. , Hort Matthew C. , Höskuldsson Ármann , Ialongo Iolanda , Ilyinskaya Evgenia , Jóhannsson Thorsteinn , Kenny Patrick , Mather Tamsin A. , Richards Nigel A. D. , Shepherd Janet
Published: August 2015

The 2014–2015 Bárðarbunga‐Veiðivötn fissure eruption at Holuhraun produced about 1.5 km3 of lava, making it the largest eruption in Iceland in more than 200 years. Over the course of the eruption, daily volcanic sulfur dioxide (SO2) emissions exceeded daily SO2 emissions from all anthropogenic sources in Europe in 2010 by at least a factor of 3. We present surface air quality observations from across Northern Europe together with satellite remote sensing data and model simulations of volcanic SO2 for September 2014. We show that volcanic SO2 was transported in the lowermost troposphere over long distances and detected by air quality monitoring stations up to 2750 km away from the source. Using retrievals from the Ozone Monitoring Instrument (OMI) and the Infrared Atmospheric Sounding Interferometer (IASI), we calculate an average daily SO2 mass burden of 99 ± 49 kilotons (kt) of SO2 from OMI and 61 ± 18 kt of SO2 from IASI for September 2014. This volcanic burden is at least a factor of 2 greater than the average SO2 mass burden between 2007 and 2009 due to anthropogenic emissions from the whole of Europe. Combining the observational data with model simulations using the United Kingdom Met Office's Numerical Atmospheric‐dispersion Modelling Environment model, we are able to constrain SO2 emission rates to up to 120 kilotons per day (kt/d) during early September 2014, followed by a decrease to 20–60 kt/d between 6 and 22 September 2014, followed by a renewed increase to 60–120 kt/d until the end of September 2014. Based on these fluxes, we estimate that the eruption emitted a total of 2.0 ± 0.6 Tg of SO2 during September 2014, in good agreement with ground‐based remote sensing and petrological estimates. Although satellite‐derived and model‐simulated vertical column densities of SO2 agree well, the model simulations are biased low by up to a factor of 8 when compared to surface observations of volcanic SO2 on 6–7 September 2014 in Ireland. These biases are mainly due to relatively small horizontal and vertical positional errors in the simulations of the volcanic plume occurring over transport distances of thousands of kilometers. Although the volcanic air pollution episodes were transient and lava‐dominated volcanic eruptions are sporadic events, the observations suggest that (i) during an eruption, volcanic SO2 measurements should be assimilated for near real‐time air quality forecasting and (ii) existing air quality monitoring networks should be retained or extended to monitor SO2 and other volcanic pollutants.
Large‐eddy simulation in an anelastic framework with closed water and entropy balances
Authors: Pressel Kyle G. , Kaul Colleen M. , Schneider Tapio , Tan Zhihong , Mishra Siddhartha
Published: August 2015

A large‐eddy simulation (LES) framework is developed for simulating the dynamics of clouds and boundary layers with closed water and entropy balances. The framework is based on the anelastic equations in a formulation that remains accurate for deep convection. As prognostic variables, it uses total water and entropy, which are conserved in adiabatic and reversible processes, including reversible phase changes of water. This has numerical advantages for modeling clouds, in which reversible phase changes of water occur frequently. The equations of motion are discretized using higher‐order weighted essentially nonoscillatory (WENO) discretization schemes with strong stability preserving time stepping. Numerical tests demonstrate that the WENO schemes yield simulations superior to centered schemes, even when the WENO schemes are used at coarser resolution. The framework is implemented in a new LES code written in Python and Cython, which makes the code transparent and easy to use for a wide user group.
Dynamics of the high‐latitude ionospheric irregularities during the 17 March 2015 St. Patrick's Day storm: Ground‐based GPS measurements
Authors: Cherniak Iurii , Zakharenkova Irina , Redmon Robert J.
Published: August 2015

We report first results on the study of the high‐latitude ionospheric irregularities observed in worldwide GPS data during the St. Patrick's Day geomagnetic storm (17 March 2015). Multisite GPS observations from more than 2500 ground‐based GPS stations were used to analyze the dynamics of the ionospheric irregularities in the Northern and Southern Hemispheres. The most intense ionospheric irregularities lasted for more than 24 h starting at 07 UT of 17 March. This period correlates well with an increase of the auroral Hemispheric Power index. We find hemispheric asymmetries in the intensity and spatial structure of the ionospheric irregularities. Over North America, the ionospheric irregularities zone expanded equatorward below ~45°N geographic latitude. Additionally, the strong midlatitude and high‐latitude GPS phase irregularities in the auroral oval were found to be related to the formation of storm enhanced density and deepening of the main ionospheric trough through upper atmosphere ionization by energetic particle precipitation. Significant increases in the intensity of the irregularities within the polar cap region of both hemispheres were associated with the formation and evolution of the storm enhanced density/tongue of ionization structures and polar patches.
Violent video game players and non‐players differ on facial emotion recognition
Authors: Diaz Ruth L. , Wong Ulric , Hodgins David C. , Chiu Carina G. , Goghari Vina M.
Published: August 2015

Violent video game playing has been associated with both positive and negative effects on cognition. We examined whether playing two or more hours of violent video games a day, compared to not playing video games, was associated with a different pattern of recognition of five facial emotions, while controlling for general perceptual and cognitive differences that might also occur. Undergraduate students were categorized as violent video game players (n = 83) or non‐gamers (n = 69) and completed a facial recognition task, consisting of an emotion recognition condition and a control condition of gender recognition. Additionally, participants completed questionnaires assessing their video game and media consumption, aggression, and mood. Violent video game players recognized fearful faces both more accurately and quickly and disgusted faces less accurately than non‐gamers. Desensitization to violence, constant exposure to fear and anxiety during game playing, and the habituation to unpleasant stimuli, are possible mechanisms that could explain these results. Future research should evaluate the effects of violent video game playing on emotion processing and social cognition more broadly. Aggr. Behav. 42:16–28, 2016. © 2015 Wiley Periodicals, Inc.
Dynamically Tunable Broadband Infrared Anomalous Refraction Based on Graphene Metasurfaces
Authors: Cheng Hua , Chen Shuqi , Yu Ping , Liu Wenwei , Li Zhancheng , Li Jianxiong , Xie Boyang , Tian Jianguo
Published: August 2015

Metasurfaces, which are capable of generating structure and wavelength dependent phase shift, have emerged as promising means for controlling the wavefront of electromagnetic waves. Finding new ways to realize broadband frequency response as well as maintaining high conversion efficiency still requires research efforts. For the design of plasmonic metasurfaces, graphene represents an attractive alternative to metals due to its strong field confinement and versatile tunability. Here, a novel metasurface based on graphene is proposed to control the wavefront of light. Dynamically tunable anomalous refraction composed of periodically patterned graphene nanocrosses for circularly polarized waves is achieved in the infrared regime. Broadband properties of anomalous refraction are demonstrated by investigating different frequencies and incident angles. Moreover, the anomalous conversion efficiency can be dynamically tuned and remain as high in a broadband frequency range by varying the Fermi energy without reoptimizing the nanostructures. This work may offer a further step in the development of a tunable wavefront controlling device.
Phosphine‐Catalyzed Regioselective and Stereoselective Hydrohalogenation Reaction of 2‐(1‐Alkynyl)‐2‐alken‐1‐ones: Synthesis of 2‐Halo‐1,3‐dienes
Authors: Li Wenbo , Gao Lihua , Yue Zhenting , Zhang Junliang
Published: August 2015

A triphenylphosphine (PPh3)‐catalyzed, regioselective and stereoselective hydrohalogenation reaction of 2‐(1‐alkynyl)‐2‐alken‐1‐ones with metal halides in the presence of acetic acid is described, furnishing functionalized 3,4‐disubstituted 2‐halo‐1,3‐dienes in moderate to good yields with high stereoselectivity and regiospecificity. The simple execution, mild conditions and the potential utilization of the products make this protocol attractive.

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Lead Replacement in CH3NH3PbI3 Perovskites
Authors: Wang Kan , Liang Ziqi , Wang Xinqiang , Cui Xudong
Published: August 2015

Superior photovoltaic performance in organic–inorganic hybrid perovskite is based on the unique properties of each moiety contined within it. Identifying the role of metal atoms in the perovskite is of great importance to explore the low‐toxicity lead‐free perovskite solar cells. By using the first‐principle calculations, four types of AMX3 (A = CH3NH3, M = Pb, Sn, Ge, Sr, X = I) perovskite materials are investigated and an attempt is made to understand the structural and electronic influences of the metal atoms on the properties of perovskites. Then, the solutions to the replacement of Pb are discussed. It is found that for the small radius metal atoms as compared with Pb, the strong geometry distortion will result in a less p–p electron transition and larger carrier effective mass. The outer ns2 electrons of the metal ions play critical roles on the modulation of the optical and electronic properties for perovskite materials. These findings suggest that the solutions to the Pb replacement might be metal or metallic clusters that have effective ionic radius and outer ns2 electrons configuration on the metal ions with low ionization energy similar to Pb2+. Based on this, lead‐free perovskite solar cells are expected to be realized in the near future.
The association between economic development, lifestyle differentiation, and C‐reactive protein concentration within rural communities in Hainan Island, China
Authors: Inoue Yosuke , Stickley Andrew , Yazawa Aki , Li Dandan , Du Jianwei , Jin Yuming , Chen Yan , Watanabe Chiho
Published: August 2015

Objective

Earlier fieldwork in rural areas of Hainan Island, China, demonstrated that during the course of economic development increasing differences had emerged in lifestyles within communities. It is possible that these variations might have stratified residents into subpopulations with different health attributes. This study examined the association between C‐reactive protein (CRP) concentration, a biomarker of future cardiovascular events, and personal lifestyle parameters and the degree of community‐level economic development among rural communities.

Methods

A cross‐sectional field survey was undertaken in 19 rural communities in Hainan. Convenience sampling was used to recruit 1,744 participants. Dried blood spot samples were collected to measure high‐sensitivity CRP concentration. Sex‐stratified multilevel regression analyses were conducted to identify factors associated with CRP concentration among the participants.

Results

While CRP concentration was negatively associated with being married and (more) education among men, for women CRP concentration was associated with the frequency of poultry consumption (P = 0.014) and the experience of migratory work in the previous year (P = 0.009). In addition, for females, living in communities with a greater degree of inequality, as indexed by the Gini coefficient, was also associated with increased CRP concentration (P = 0.003).

Conclusion

Given that CRP concentration is a marker of future CVD risk, this study suggests that within these previously homogenous rural communities, economic development might have stratified people into population subgroups with a different CVD risk. Am. J. Hum. Biol. 28:186–196, 2016. © 2015 Wiley Periodicals, Inc.
Chronic pain in Noonan Syndrome: A previously unreported but common symptom
Authors: Vegunta Sravanthi , Cotugno Richard , Williamson Amber , Grebe Theresa A.
Published: August 2015

Noonan syndrome (NS) is a multiple malformation syndrome characterized by pulmonic stenosis, cardiomyopathy, short stature, lymphatic dysplasia, craniofacial anomalies, cryptorchidism, clotting disorders, and learning disabilities. Eight genes in the RAS/MAPK signaling pathway are implicated in NS. Chronic pain is an uncommon feature. To investigate the prevalence of pain in NS, we distributed a two‐part questionnaire about pain among NS individuals at the Third International Meeting on Genetic Syndromes of the Ras/MAPK Pathway. The first part of the questionnaire queried demographic information among all NS participants. The second part was completed by individuals with chronic pain. Questions included musculoskeletal problems and clinical features of pain. Forty‐five questionnaires were analyzed; 53% of subjects were female. Mean age was 17 (2–48) years; 47% had a PTPN11 mutation. Sixty‐two percent (28/45) of individuals with NS experienced chronic pain. There was a significant relationship between prevalence of pain and residing in a cold climate (P = 0.004). Pain occurred commonly in extremities/joints and head/trunk, but more commonly in extremities/joints (P = 0.066). Subjects with hypermobile joints were more likely to have pain (P = 0.052). Human growth hormone treatment was not statistically significant among subjects without chronic pain (P = 0.607). We conclude that pain is a frequent and under‐recognized clinical feature of NS. Chronic pain may be associated with joint hypermobility and aggravated by colder climate. Our study is a preliminary investigation that should raise awareness about pain as a common symptom in children and adults with NS. © 2015 Wiley Periodicals, Inc.
Homozygous deletion of TRMT10A as part of a contiguous gene deletion in a syndrome of failure to thrive, delayed puberty, intellectual disability and diabetes mellitus
Authors: Zung Amnon , Kori Michal , Burundukov Ella , Ben‐Yosef Tamar , Tatoor Yasmin , Granot Esther
Published: August 2015

Two recent reports describe a new syndrome of intellectual disability, short stature, microcephaly, and young onset diabetes or disturbed glucose metabolism in association with inactivating mutations in the TRMT10A gene. We investigated the clinical spectrum presented by a 17‐year‐old female with a homozygous contiguous gene deletion involving the TRMT10A gene. From infancy, she presented with failure to thrive and microcephaly. Puberty was characterized by a slow and an inconsistent course of progression. Concomitantly, gonadotropin levels fluctuated between low and high levels which were compatible with gonadal failure. Unlike the previous reports, the patient had ketoacidosis at onset of diabetes and islet cell autoantibodies. Nevertheless, glycemic control was excellent (HbA1C 5.0%–6.2%). RT‐PCR and Western blot analysis demonstrated a complete abolishment of TRMT10A mRNA and its translated protein. In order to elucidate the nature of diabetes in this patient, endogenous insulin secretion and glycemic control were evaluated by a glucagon stimulation test and continuous glucose monitoring both during insulin treatment and off therapy. Endogenous insulin secretion still persisted 22 months after onset of diabetes and relatively normal glucose levels were kept over 3 days without insulin treatment. The fluctuating course of puberty and diabetes may reflect intermittent apoptotic damages due to sensitization of the relevant cells to various stress agents in the absence of functional TRMT10A. © 2015 Wiley Periodicals, Inc.
Copy number variations in multiple sclerosis and neuromyelitis optica
Authors: Sato Shinya , Yamamoto Ken , Matsushita Takuya , Isobe Noriko , Kawano Yuji , Iinuma Kyoko , Niino Masaaki , Fukazawa Toshiyuki , Nakamura Yuri , Watanabe Mitsuru , Yonekawa Tomomi , Masaki Katsuhisa , Yoshimura Satoshi , Murai Hiroyuki , Yamasaki Ryo , Kira Jun‐ichi ,   and the Japan Multiple Sclerosis Genetics Consortium
Published: August 2015

Objective

To clarify the potential association of copy number variations (CNVs) with multiple sclerosis (MS) and neuromyelitis optica (NMO) in Japanese cases.

Methods

Genome‐wide association analyses of CNVs among 277 MS patients, 135 NMO/NMO spectrum disorder (NMOSD) patients, and 288 healthy individuals as a discovery cohort, and among 296 MS patients, 76 NMO/NMOSD patients, and 790 healthy individuals as a replication cohort were performed using high‐density single nucleotide polymorphism microarrays.

Results

A series of discovery and replication studies revealed that most identified CNVs were 5 to 50kb deletions at particular T cell receptor (TCR) gamma and alpha loci regions. Among these CNVs, a TCR gamma locus deletion was found in 16.40% of MS patients (p = 2.44E‐40, odds ratio [OR] = 52.6), and deletion at the TCR alpha locus was found in 17.28% of MS patients (p = 1.70E‐31, OR = 13.0) and 13.27% of NMO/NMOSD patients (p = 5.79E‐20, OR = 54.6). These CNVs were observed in peripheral blood T‐cell subsets only, suggesting the CNVs were somatically acquired. NMO/NMOSD patients carrying the CNV tended to be seronegative for anti–aquaporin‐4 antibody or had significantly lower titers than those without CNV.

Interpretation

Deletion‐type CNVs at specific TCR loci regions contribute to MS and NMO susceptibility. Ann Neurol 2015;78:Ann Neurol 2015;78:679–696
Dendronized Hyperbranched Macromolecules: Soft Matter with a Novel Type of Segmental Distribution
Authors: Lederer Albena , Burchard Walther , Hartmann Tobias , Haataja Johannes S. , Houbenov Nikolay , Janke Andreas , Friedel Peter , Schweins Ralf , Lindner Peter
Published: August 2015

Dendronization of a hyperbranched polyester with different generation dendrons leads to pseudo‐dendritic structures. The hyperbranched core is modified by the divergent coupling of protected monomer units to the functional groups. Compared to dendrimers, the synthetic effort is significantly less, but the properties are very close to those of high‐generation dendrimers. The number of functional groups, molar mass, and rheology behavior even in the early generation (G1–G4) pseudo‐dendrimers strongly resembles the behavior of dendrimers in higher generations (G5–G8). Comparison of the segmental and internal structure with perfect dendrimers is performed using SANS, dynamic light scattering and viscosity analysis, microscopy and molecular dynamics simulation. The interpretation of the results reveals unique structural characteristics arising from lower segmental density of the core, which turns into a soft nano‐sphere with a smooth surface even in the first generation.
Observation of a Thermally Accessible Triplet State Resulting from Rotation around a Main‐Group π Bond
Authors: Kostenko Arseni , Tumanskii Boris , Karni Miriam , Inoue Shigeyoshi , Ichinohe Masaaki , Sekiguchi Akira , Apeloig Yitzhak
Published: August 2015

We report the first direct spectroscopic observation by electron paramagnetic resonance (EPR) spectroscopy of a triplet diradical that is formed in a thermally induced rotation around a main‐group π bond, that is, the SiSi double bond of tetrakis(di‐tert‐butylmethylsilyl)disilene (1). The highly twisted ground‐state geometry of singlet 1 allows access to the perpendicular triplet diradical 2 at moderate temperatures of 350–410 K. DFT‐calculated zero‐field splitting (ZFS) parameters of 2 accurately reproduce the experimentally observed half‐field transition. Experiment and theory suggest a thermal equilibrium between 1 and 2 with a very low singlet–triplet energy gap of only 7.3 kcal mol−1.
Detection of dependence patterns with delay
Authors: Chevallier Julien , Laloë Thomas
Published: August 2015

The Unitary Events (UE) method is a popular and efficient method used this last decade to detect dependence patterns of joint spike activity among simultaneously recorded neurons. The first introduced method is based on binned coincidence count (Grün, 1996) and can be applied on two or more simultaneously recorded neurons. Among the improvements of the methods, a transposition to the continuous framework has recently been proposed by Muiño and Borgelt (2014) and fully investigated by Tuleau‐Malot et al. (2014) for two neurons. The goal of the present paper is to extend this study to more than two neurons. The main result is the determination of the limit distribution of the coincidence count. This leads to the construction of an independence test between neurons. Finally, we propose a multiple test procedure via a Benjamini and Hochberg approach (Benjamini and Hochberg, 1995). All the theoretical results are illustrated by a simulation study, and compared to the UE method proposed by Grün et al. (2002). Furthermore our method is applied on real data.
Membrane‐induced structure of novel human tachykinin hemokinin‐1 (hHK1)
Authors: Ganjiwale Anjali , Cowsik Sudha M.
Published: August 2015

PPT‐C encoded hemokinin‐1(hHK‐1) of Homo sapiens (TGKASQFFGLM) is a structurally distinct neuropeptide among the tachykinin family that participate in the NK‐1 receptor downstream signaling processes. Subsequently, signal transduction leads to execution of various effector functions which includes aging, immunological, and central nervous system (CNS) regulatory actions. However the conformational pattern of ligand receptor binding is unclear. The three‐dimensional structure of the hemokinin‐1 in aqueous and micellar environment has been studied by one and two‐dimensional proton nuclear magnetic resonance (2D 1H‐NMR spectroscopy) and distance geometry calculations. Data shows that hemokinin‐1 was unstructured in aqueous environment; anionic detergent SDS induces α‐helix formation. Proton NMR assignments have been carried out with the aid of correlation spectroscopy (gradient‐COSY and TOCSY) and nuclear Overhauser effect spectroscopy (NOESY and ROESY) experiments. The inter proton distances and dihedral angle constraints obtained from the NMR data have been used in torsion angle dynamics algorithm for NMR applications (CYANA) to generate a family of structures, which have been refined using restrained energy minimization and dynamics. Helical conformation is observed from residue K3‐M11. The conformational range of the peptide revealed by NMR studies has been analyzed in terms of characteristic secondary features. Observed conformational features have been compared to that of Substance P potent NK1 agonist. Thus the report provides a structural insight to study hHK‐1‐NK1 interaction that is essential for hHK1 based signaling events. © 2015 Wiley Periodicals, Inc. Biopolymers 103: 702–710, 2015.
Biomimetic repeat protein derived from Xenopus tropicalis for fibrous scaffold fabrication
Authors: Kwon Yunkyeoung , Yang Yun Jung , Jung Dooyup , Hwang Byeong Hee , Cha Hyung Joon
Published: August 2015

Collagen, silk, and elastin are the fibrous proteins consist of representative amino acid repeats. Because these proteins exhibited distinguishing mechanical properties, they have been utilized in diverse applications, such as fiber‐based sensors, filtration membranes, supporting materials, and tissue engineering scaffolds. Despite their infinite prevalence and potential, most studies have only focused on a few repeat proteins. In this work, the hypothetical protein with a repeat motif derived from the frog Xenopus tropicalis was obtained and characterized for its potential as a novel protein‐based material. The codon‐optimized recombinant frog repeat protein, referred to as ‘xetro’, was produced at a high rate in a bacterial system, and an acid extraction‐based purified xetro protein was successfully fabricated into microfibers and nanofibers using wet spinning and electrospinning, respectively. Specifically, the wet‐spun xetro microfibers demonstrated about 2‐ and 1.5‐fold higher tensile strength compared with synthetic polymer polylactic acid and cross‐linked collagen, respectively. In addition, the wet‐spun xetro microfibers showed about sevenfold greater stiffness than collagen. Therefore, the mass production potential and greater mechanical properties of the xetro fiber may result in these fibers becoming a new promising fiber‐based material for biomedical engineering. © 2015 Wiley Periodicals, Inc. Biopolymers 103: 659–664, 2015.
Inter‐microcarrier transfer and phenotypic stability of stem cell‐derived Schwann cells in stirred suspension bioreactor culture
Authors: Shakhbazau Antos , Mirfeizi Leila , Walsh Tylor , Wobma Holly M. , Kumar Ranjan , Singh Bhagat , Kallos Michael S. , Midha Rajiv
Published: August 2015

Emerging bioreactor technologies offer an effective way for scaled‐up production of large numbers of cells for cell therapy applications. One of the clinical paradigms where cell therapy can be an asset is restorative neurosciences. Nerve repair can benefit from the injections of stem cells and/or Schwann cells, acting as a source for axon myelination, myelin debris clearance, and trophic support. We have adapted microcarrier‐based suspension bioreactor culture for Schwann cells (SCs) differentiated from a new stem cell source – skin‐derived precursors (SKPs). SKP‐derived SCs attach and grow on different types of microcarriers in both static and stirred culture, with Cytodex 3 and CultiSpher‐S found most effective. Inter‐microcarrier migration of SKP‐SCs represents a key mechanism for rapid expansion and colonization in stirred suspension culture. We have shown that microcarrier‐expanded SKP‐SCs cells express Schwann cell markers p75‐NTR, GFAP and S100 and retain their key ability to myelinate axons both in vitro and in vivo. Scaled‐up microcarrier‐based production of SKP‐SCs in suspension bioreactors appears feasible for timely generation of sufficient cell numbers for nerve repair strategies. Biotechnol. Bioeng. 2016;113: 393–402. © 2015 Wiley Periodicals, Inc.