bluuebunny/crossref_metadata_2025_split huggingface dataset:
Modeling ash fall distribution from a Yellowstone supereruption
Authors: Mastin Larry G. , Van Eaton Alexa R. , Lowenstern Jacob B. 
Published: August 2014

AbstractWe used the volcanic ash transport and dispersion model Ash3d to estimate the distribution of ashfall that would result from a modern‐day Plinian supereruption at Yellowstone volcano. The simulations required modifying Ash3d to consider growth of a continent‐scale umbrella cloud and its interaction with ambient wind fields. We simulated eruptions lasting 3 days, 1 week, and 1 month, each producing 330 km3 of volcanic ash, dense‐rock equivalent (DRE). Results demonstrate that radial expansion of the umbrella cloud is capable of driving ash upwind (westward) and crosswind (N‐S) in excess of 1500 km, producing more‐or‐less radially symmetric isopachs that are only secondarily modified by ambient wind. Deposit thicknesses are decimeters to meters in the northern Rocky Mountains, centimeters to decimeters in the northern Midwest, and millimeters to centimeters on the East, West, and Gulf Coasts. Umbrella cloud growth may explain the extremely widespread dispersal of the ∼640 ka and 2.1 Ma Yellowstone tephra deposits in the eastern Pacific, northeastern California, southern California, and South Texas.
Properties of low‐latitude mantle plasma in the Earth's magnetotail: ARTEMIS observations and global MHD predictions
Authors: Wang Chih‐Ping , Lyons Larry R. , Angelopoulos Vassilis 
Published: August 2014

AbstractThe Earth's plasma mantle is one of the major suppliers of particles for the plasma sheet. To understand its plasma characteristics, spatial distributions, and dependencies on interplanetary magnetic field (IMF) direction, we statistically analyzed the Acceleration, Reconnection, Turbulence, and Electrodynamics of Moon's Interaction with the Sun (ARTEMIS) observations in the low‐latitude magnetotail (~10 RE above and below the current sheet) and investigated the predictions from global Block Adaptive Tree Solar wind‐Roe‐Upwind Scheme MHD simulations. The mantle plasma flows tailward along magnetic field lines (~50–200 km/s) and at the same time drifts toward midnight and toward the current sheet. The mantle plasma has similar temperature (~0.05–0.2 keV) to the magnetosheath plasma but has lower density (~0.1–1 cm−3). The mantle appearance is dawn‐dusk asymmetric depending mainly on the IMF By direction. The occurrence rates, density, and V|| all decrease with decreasing |Y|. This density cross‐tail profile suggests that the low‐latitude mantle plasma mainly comes from the magnetosheath entering through the tail magnetopause along the open field lines. Density is highly and positively correlated with V||. These observations are qualitatively consistent with the MHD results. The simulations indicate that as IMF By becomes dominant, the source locations at the magnetopause for the mantle move to lower latitudes and become dawn‐dusk asymmetric, and the tail cross section also becomes distorted with the magnetopause shape elongating and the current sheet tilting significantly. Degrees of these changes also vary with the downtail distances and IMF Bz direction. The source location change leads to the dawn‐dusk asymmetric mantle appearance. The tail cross‐section change alters the distance from the sources to the current sheet and thus the resulting mantle density distributions just outside the plasma sheet.
A case study of ionospheric storm effects during long‐lasting southward IMF Bz‐driven geomagnetic storm
Authors: Liu Jing , Liu Libo , Nakamura Takuji , Zhao Biqiang , Ning Baiqi , Yoshikawa A. 
Published: August 2014

AbstractMultiple instrumental observations including GPS total electron content (TEC), foF2 and hmF2 from ionosondes, vertical ion drift measurements from Communication/Navigation Outage Forecasting System, magnetometer data, and far ultraviolet airglow measured by Thermosphere, Ionosphere, Mesosphere Energetics and Dynamics/Global Ultraviolet Imager (TIMED/GUVI) are used to investigate the profound ionospheric disturbances at midlatitude and low latitude during the 14–17 July 2012 geomagnetic storm event, which was featured by prolonged southward interplanetary geomagnetic field component for about 30 h below −10 nT. In the East Asian/Australian sector, latitudinal profile of TEC variations in the main phase were characterized by three bands of increments and separated by weak depressions in the equatorial ionospheric anomaly (EIA) crest regions, which were caused by the combined effects of disturbance dynamo electric fields (DDEF) and equatorward neutral winds. In the recovery phase, strong inhibition of EIA occurred and the summer crest of EIA disappeared on 16 July due to the combined effects of intrusion of neutral composition disturbance zone as shown by the TIMED/GUVI O/N2 measurements and long‐lasting daytime westward DDEF inferred from the equatorial electrojet observations. The transit time of DDEF over the dip equator from westward to eastward is around 2200 LT. In the American longitude, the salient ionospheric disturbances in the summer hemisphere were characterized by daytime periodical intrusion of negative phase for three consecutive days in the recovery phase, preceded by storm‐enhanced density plume in the initial phase. In addition, multiple short‐lived prompt penetration electric fields appeared during stable southward interplanetary magnetic field (IMF) Bz in the recovery phase and were responsible for enhanced the EIA and equatorial ionospheric uplift around sunset.
Convective turbulent dust emission (CTDE) observed over Horqin Sandy Land area and validation of a CTDE scheme
Authors: Li X. L. , Klose M. , Shao Y. , Zhang H. S. 
Published: August 2014

AbstractIn this paper, a data set obtained from a sandstorm monitoring station located in Horqin Sandy Land area in northern China from December 2010 to November 2011 is used to investigate the seasonal variations and characteristics of convective turbulent dust emission (CTDE) and to validate a CTDE scheme. The observations show that CTDE events occur during the local daytime, with 85% of them between 08:00 and 15:00 local standard time. While a CTDE event may last for 0.5 to 8 h, the duration of 79% of the events is shorter than 3 h. CTDE occurs most frequently in summer and then in fall, less frequently in spring, and least in winter. The total CTDE flux in the year (=1.63 × 104 µg m−2 s−1) is considerable and important to the background dust concentration and dust cycles from the view of a longer time scale. The CTDE dust flux, Fobs, falls into the range of 0–30 µg m−2 s−1 and is positively correlated with the convective scaling velocity, w*, but not so much with the friction velocity, u*. A CTDE event was observed on 14 October 2011, which lasted for 7 h with a maximum of Fobs = 9.4 µg m−2 s−1. This event is used to validate the CTDE scheme. A linear relationship between the predicted and the observed CTDE dust fluxes is found, and an important model parameter is calibrated for this sandy land.
Variability of upper tropospheric clouds in the polar region during stratospheric sudden warmings
Authors: Kohma Masashi , Sato Kaoru 
Published: August 2014

AbstractThe variability of upper tropospheric clouds during stratospheric sudden warmings (SSWs) in 2009, 2010, and 2012 in the Northern Hemisphere is examined using satellite observations and reanalysis data. It is shown that the zonal mean cloud frequency decreases in the altitude range of 8–12 km, and the mean cloud top height descends soon after an SSW. Following a sudden decrease in upper tropospheric cloud frequency, an increase in temperature and static stability around the tropopause and a downward shift of the tropopause height are simultaneously observed. These changes in the upper troposphere are observed when the downward residual mean flow associated with an SSW becomes stronger around the tropopause level. By means of analyses based on a recent theory of three‐dimensional residual mean flow, it is shown that the horizontal structure of the vertical flow is consistent with the geographical distribution of clouds in the altitude range of 9–11 km. Another interesting feature is that the low cloud frequency in the upper troposphere that starts after an SSW continues for more than 1 month. Possible reasons are discussed in terms of a long radiative relaxation time and a change in the tropospheric wave activity. These findings indicate that SSWs can affect the tropospheric radiative budget through the modification of cloud frequency and cloud top heights.
A new multispectral cloud retrieval method for ship‐based solar transmissivity measurements
Authors: Brückner M. , Pospichal B. , Macke A. , Wendisch M. 
Published: August 2014

AbstractWithin the German Leibniz‐network OCEANET project, ship‐based lidar and microwave remote sensing as well as spectral zenith radiance observations with the COmpact RAdiation measurements System (CORAS) were performed. During three cruises latitudes between 50°N and 50°S were covered. A new spectral retrieval method to derive the cloud optical thickness τ and the droplet effective radius reff using CORAS measurements is developed. The method matches CORAS measurements of ratios of spectral transmissivity at six wavelengths with modeled transmissivities. This retrieval is fast and accurate and thus suitable for operational purposes. The new approach circumvents ambiguities of existing cloud retrievals and reduces the influence of measurement uncertainties. It is applied to homogenous and heterogeneous liquid water and cirrus clouds. In boundary layer liquid water clouds, the retrieved effective radius was more variable, whereas in the cirrus it was rather constant. Furthermore, the liquid water path LWP was derived and compared to data from a microwave radiometer. The new retrieval tends to overestimate LWP for thick liquid water clouds but slightly underestimate LWP for thin clouds. The presented method cannot be applied to mixed‐phase clouds. The maximum retrieval of τ and reff for liquid water clouds is 80 in τ and 30 μm in reff, respectively; for cirrus clouds the limitations of the retrieval are 10 in τ and 60 μm in reff.
A generalized equilibrium model for predicting daily to interannual shoreline response
Authors: Splinter Kristen D. , Turner Ian L. , Davidson Mark A. , Barnard Patrick , Castelle Bruno , Oltman‐Shay Joan 
Published: August 2014

AbstractCoastal zone management requires the ability to predict coastline response to storms and longer‐term seasonal to interannual variability in regional wave climate. Shoreline models typically rely on extensive historical observations to derive site‐specific calibration. To circumvent the challenge that suitable data sets are rarely available, this contribution utilizes twelve 5+ year shoreline data sets from around the world to develop a generalized model for shoreline response. The shared dependency of model coefficients on local wave and sediment characteristics is investigated, enabling the model to be recast in terms of these more readily measurable quantities. Study sites range from microtidal to macrotidal coastlines, spanning moderate‐ to high‐energy beaches. The equilibrium model adopted here includes time varying terms describing both the magnitude and direction of shoreline response as a result of onshore/offshore sediment transport between the surf zone and the beach face. The model contains two coefficients linked to wave‐driven processes: (1) the response factor (φ) that describes the “memory” of a beach to antecedent conditions and (2) the rate parameter (c) that describes the efficiency with which sand is transported between the beach face and surf zone. Across all study sites these coefficients are shown to depend in a predictable manner on the dimensionless fall velocity (Ω), that in turn is a simple function of local wave conditions and sediment grain size. When tested on an unseen data set, the new equilibrium model with generalized forms ofφandcexhibited high skill (Brier Skills Score, BSS = 0.85).
Morphology and controls on the position of a gravel‐sand transition: Fraser River, British Columbia
Authors: Venditti Jeremy G. , Church Michael 
Published: August 2014

AbstractAlluvial river channels often exhibit a relatively abrupt transition from gravel‐ to sand‐bedded conditions. The phenomenon is well documented, but few prior studies have analyzed the spatial variability through reaches where transitions occur. The downstream fining pattern observed in the Fraser River is cited as a classic example of an abrupt gravel‐sand transition in a large alluvial channel. However, important questions regarding the exact location of the transition, its sedimentology and morphology, and what controls its location remain unanswered. Here we present observations of the downstream change in bed material grain size, river bed topography, and channel hydraulics through the reach within which the transition occurs. These observations indicate that the gravel‐sand transition is characterized by a terminating gravel wedge, but there are patches of gravel downstream of the wedge forming a diffuse extension. We show that there is a dramatic decrease in shear stress at the downstream end of the wedge and a consequent cessation of general gravel mobility. We argue that the patches of gravel observed beyond the wedge are the result of enhanced mobility of fine gravel over a sand bed. We also find that sand in suspension declines rapidly at the downstream end of the wedge, suggesting that sand is delivered to the bed, completing the sedimentary conditions for a gravel‐sand transition. We propose that the break in river slope associated with the transition is a consequential feature of the transition.
Impacts of forest harvest on cold season land surface conditions and land‐atmosphere interactions in northern Great Lakes states
Authors: Garcia Matthew , Özdogan Mutlu , Townsend Philip A. 
Published: August 2014

AbstractLand cover change, including temporary disturbances such as forest harvests, can significantly affect established regimes of surface energy balance and moisture exchange, altering flux processes that drive weather and climate. We examined the impacts of forest harvest on winter land‐atmosphere interactions in a temperate region using high‐resolution numerical modeling methods in paired simulations. Using the WRF‐ARW atmospheric model and the Noah land surface model, we simulated the balance of surface sensible and latent heat fluxes and the development and dissipation of a stable nocturnal boundary layer during generally calm synoptic conditions. Our results show reduced daily‐average snow‐covered land surface sensible heat flux (by 80%) and latent heat flux (by 60%) to the atmosphere in forest clearings due to albedo effects and rebalancing of the surface energy budget. We found a land surface cooling effect (−8 W m−2) in snow‐covered cleared areas, consistent with prior modeling studies and conceptual understanding of the mechanisms for midlatitude deforestation to offset anthropogenic global warming at local scales. Results also demonstrate impacts of forest clearing on the passage of a weak cold front due to altered near‐surface winds and boundary layer stability. We show significant differences in both surface conditions and fluxes between harvested and undisturbed forest areas. Our results demonstrate the potential utility of high‐resolution remote sensing analyses to represent transient land cover changes in model simulations of weather and climate, which are usually undertaken at coarser resolutions and often overlook these changes at the land surface.
Effects of transionospheric signal decorrelation on Global Navigation Satellite Systems (GNSS) performance studied from irregularity dynamics around the northern crest of the EIA
Authors: Das T. , Roy B. , Paul A. 
Published: August 2014

AbstractTransionospheric satellite navigation links operate primarily at L band and are frequently subject to severe degradation of performances arising out of ionospheric irregularities. Various characteristic features of equatorial ionospheric irregularity bubbles like the drift velocity, characteristic velocity, decorrelation time, and decorrelation distance can be determined using spaced aerial measurements at VHF. These parameters measured at VHF from a station Calcutta situated near the northern crest of the Equatorial Ionization Anomaly (EIA) in the geophysically sensitive Indian longitude sector have been correlated with L band scintillation indices and GPS position accuracy parameters for identifying possible proxies to L band scintillations. Good correspondences have been observed between decorrelation times and distances at VHF with GPS S4 and Position Dilution of Precision during periods of GPS scintillations (S4 > 0.3) for February–April 2011, August–October 2011, and February–April 2012. A functional relation has been developed between irregularity drift velocity measured at VHF and S4 at L band during February–April 2011, and validation of measured S4 and predicted values performed during August–October 2011 and February–April 2012. Significant improvement in L band scintillation prediction and consequent navigational accuracy will result using such relations derived from VHF irregularity measurements which are much simpler and inexpensive.
Cancer mortality among Brazilian dentists
Authors: Koifman Sergio , Malhão Thainá Alves , Pinto de Oliveira Gisele , de Magalhães Câmara Volney , Koifman Rosalina Jorge , Meyer Armando 
Published: August 2014

BackgroundPrevious studies have variably shown excess risks of elected cancers among dentists.MethodsNational Brazilian mortality data were used to obtain mortality patterns among dentists between 1996 and 2004. Cancer mortality odds ratios (MORs) and cancer proportional mortality ratios for all cancer sites were calculated, using the general population and physicians and lawyers as comparison groups.ResultsFemale dentists from both age strata showed higher risks for breast, colon‐rectum, lung, brain, and non‐Hodgkin lymphoma. Compared to physicians and lawyers, higher MOR estimates were observed for brain cancer among female dentists 20–49 yr. Among male dentists, higher cancer mortality was found for colon‐rectum, pancreas, lung, melanoma, and non‐Hodgkin lymphoma. Higher risk estimates for liver, prostate, bladder, brain, multiple myeloma and leukemia were observed among 50–79 yr old male dentists.DiscussionIf confirmed, these results indicate the need for limiting occupational exposures among dentists in addition to establishing screening programs to achieve early detection of selected malignant tumors. Am. J. Ind. Med. 57:1255–1264, 2014. © 2014 Wiley Periodicals, Inc.
Epigenetic therapy for Friedreich ataxia
Authors: Soragni Elisabetta , Miao Wenyan , Iudicello Marco , Jacoby David , De Mercanti Stefania , Clerico Marinella , Longo Filomena , Piga Antonio , Ku Sherman , Campau Erica , Du Jintang , Penalver Pablo , Rai Myriam , Madara Joseph C. , Nazor Kristopher , O'Connor Melinda , Maximov Anton , Loring Jeanne F. , Pandolfo Massimo , Durelli Luca , Gottesfeld Joel M. , Rusche James R. 
Published: August 2014

ObjectiveTo investigate whether a histone deacetylase inhibitor (HDACi) would be effective in an in vitro model for the neurodegenerative disease Friedreich ataxia (FRDA) and to evaluate safety and surrogate markers of efficacy in a phase I clinical trial in patients.MethodsWe used a human FRDA neuronal cell model, derived from patient induced pluripotent stem cells, to determine the efficacy of a 2‐aminobenzamide HDACi (109) as a modulator of FXN gene expression and chromatin histone modifications. FRDA patients were dosed in 4 cohorts, ranging from 30mg/day to 240mg/day of the formulated drug product of HDACi 109, RG2833. Patients were monitored for adverse effects as well as for increases in FXN mRNA, frataxin protein, and chromatin modification in blood cells.ResultsIn the neuronal cell model, HDACi 109/RG2833 increases FXN mRNA levels and frataxin protein, with concomitant changes in the epigenetic state of the gene. Chromatin signatures indicate that histone H3 lysine 9 is a key residue for gene silencing through methylation and reactivation through acetylation, mediated by the HDACi. Drug treatment in FRDA patients demonstrated increased FXN mRNA and H3 lysine 9 acetylation in peripheral blood mononuclear cells. No safety issues were encountered.InterpretationDrug exposure inducing epigenetic changes in neurons in vitro is comparable to the exposure required in patients to see epigenetic changes in circulating lymphoid cells and increases in gene expression. These findings provide a proof of concept for the development of an epigenetic therapy for this fatal neurological disease. Ann Neurol 2014;76:489–508
Kombinierte Rhodium‐ und Photoredoxkatalyse in der C‐H‐Funktionalisierung von Arenen: oxidative Heck‐Reaktionen mit sichtbarem Licht
Authors: Fabry David C. , Zoller Jochen , Raja Sadiya , Rueping Magnus 
Published: August 2014

AbstractDirekte oxidative metallkatalysierte C‐H‐Funktionalisierungen von Arenen haben sich in den letzten Jahren zu einem wichtigen Gebiet der organischen Synthesechemie entwickelt. Häufig werden in diesen Reaktionen (über)stöchiometrische Mengen an organischen oder anorganischen Oxidantien verwendet. Die Kombination von Rhodiumkatalyse und Photoredoxkatalyse mit sichtbarem Licht ermöglichte nun die direkte katalytische C‐H‐Olefinierung von Arenen. Geringe Mengen (1 Mol‐%) des Photoredoxkatalysators und milde Reaktionsbedingungen erlauben eine effiziente C‐H‐Funktionalisierung mit guter Substratbreite.
A Biomimetic Synthesis of (±)‐Basiliolide B
Authors: Min Long , Zhang Yang , Liang Xuefeng , Huang Junrong , Bao Wenli , Lee Chi‐Sing 
Published: August 2014

AbstractA highly diastereoselective and practical biomimetic total synthesis of (±)‐basiliolide B has been achieved through the study of the two proposed biosynthetic pathways (O‐methylation and O‐acylation) for the unprecedented 7‐methoxy‐4,5‐dihydro‐3H‐oxepin‐2‐one (C ring). The synthesis featured a cyclopropanation/ring opening strategy for establishing the stereogenic centers at C8 and C9, a biomimetic 2‐pyrone Diels–Alder cycloaddition for the synthesis of the ABD ring system, and finally a highly efficient biomimetic intramolecular O‐acylation for the C ring formation. This result provides an important perspective on the biosynthetic origin of the unprecedented 7‐membered acyl ketene acetal moiety of the C ring.
Sustainable Electrical Energy Storage through the Ferrocene/Ferrocenium Redox Reaction in Aprotic Electrolyte
Authors: Zhao Yu , Ding Yu , Song Jie , Li Gang , Dong Guangbin , Goodenough John B. , Yu Guihua 
Published: August 2014

AbstractThe large‐scale, cost‐effective storage of electrical energy obtained from the growing deployment of wind and solar power is critically needed for the integration into the grid of these renewable energy sources. Rechargeable batteries having a redox‐flow cathode represent a viable solution for either a Li‐ion or a Na‐ion battery provided a suitable low‐cost redox molecule soluble in an aprotic electrolyte can be identified that is stable for repeated cycling and does not cross the separator membrane to the anode. Here we demonstrate an environmentally friendly, low‐cost ferrocene/ferrocenium molecular redox couple that shows about 95 % energy efficiency and about 90 % capacity retention after 250 full charge/discharge cycles.