bluuebunny/crossref_metadata_2025_split huggingface dataset:
Impact of increasing inflow of warm Atlantic water on the sea‐air exchange of carbon dioxide and methane in the Laptev Sea
Authors: Wåhlström Iréne , Dieterich Christian , Pemberton Per , Meier H. E. Markus 
Published: June 2016

AbstractThe Laptev Sea is generally a sink for atmospheric carbon dioxide and a source of methane to the atmosphere. We investigate how sensitive the net sea‐air exchange of carbon dioxide and methane in the Laptev Sea are to observed changes in the inflow of Atlantic water into the Arctic Ocean and in atmospheric conditions occurring after 1990. Using a time‐dependent coupled physical‐biogeochemical column model, both the physical and biogeochemical effects are investigated in a series of sensitivity experiments. The forcing functions are kept constant at 40 year climatological values except successively selected drivers that vary in time. Their effects are examined by comparing two periods, 1971–1989 and 1991–2009. We find that the flux of carbon dioxide is more sensitive to the increased Atlantic water inflow than the methane exchange. The increased volume transport of water in the Atlantic layer increases the ocean net uptake of carbon dioxide more than the warming of the incoming bottom water as the vertical advection is enhanced in the first case. The methane cycling is mainly affected by the increase in temperature, irrespective of whether the warming originates from the atmosphere or the incoming bottom water, causing increased outgassing to the atmosphere. In summary, our results suggest that the observed changes in the atmosphere and ocean potentially had a substantial impact on carbon dioxide uptake on the Siberian Shelf. However, the results suggest that the impact on the outgassing of methane might have been relatively modest compared to the interannual variability of sea‐air fluxes of methane.
Characterization of the impact of GLONASS observables on receiver bias estimation for ionospheric studies
Authors: Vergados Panagiotis , Komjathy Attila , Runge Thomas F. , Butala Mark D. , Mannucci Anthony J. 
Published: June 2016

AbstractThis study investigates the impact of including the Russian Globalnaya Navigazionnaya Sputnikovaya Sistema (GLONASS) and Global Positioning System (GPS) observables in the estimation of the GPS satellite and receiver interfrequency delay biases. Efforts to advance the total electron content accuracy are directly linked to improving the satellite and receiver bias estimation. This analysis is a preliminary assessment of the impact of including GLONASS observables in the bias estimation process. We analyze bias series from 84 globally distributed stations between 17 February 2015 and 31 March 2015. We find that inclusion of GLONASS observables in the biases retrieval algorithm systematically reduces receiver biases at 88% of the stations than when only GPS observables are used. The difference is <1.0 total electron content unit (TECU; 1 TECU = 1016 el m−2), which falls within the bias retrieval uncertainty. However, due to its systematic behavior it must be characterized and documented. We also compare the bias series between two centers, the Jet Propulsion Laboratory and the Center for Orbit Determination in Europe. Our analysis shows that the mean difference between the two centers varies from station to station, with a value <1.0 TECU for 57% of the stations, suggesting an excellent intercenter agreement. For the other stations, the differences can reach up to 5.0 TECU. Finally, the stability of the bias retrievals over time is latitudinally dependent. Low‐latitude and middle‐latitude stations exhibit systematically the largest and smallest scatter, respectively, whereas stations at high latitudes obtain intermediate values.
Three methods to retrieve slant total electron content measurements from ground‐based GPS receivers and performance assessment
Authors: Zhang Baocheng 
Published: June 2016

AbstractThe high sampling rate along with the global coverage of ground‐based receivers makes Global Positioning System (GPS) data particularly ideal for sensing the Earth's ionosphere. Retrieval of slant total electron content measurements (TECMs) constitutes a key first step toward extracting various ionospheric parameters from GPS data. Within the ionospheric community, the interpretation of TECM is widely recognized as the slant total electron content along the satellite receiver line of sight, biased by satellite and receiver differential code biases (DCBs). The Carrier‐to‐Code Leveling (CCL) has long been used as a geometry‐free method for retrieving TECM, mainly because of its simplicity and effectiveness. In fact, however, the CCL has proven inaccurate as it may give rise to TECM very susceptible to so‐called leveling errors. With the goal of attaining more accurate TECM retrieval, we report in this contribution two other methods than the CCL, namely, the Precise Point Positioning (PPP) and the Array‐aided PPP (A‐PPP). The PPP further exploits the International GPS Service (IGS) orbit and clock products and turns out to be a geometry‐based method. The A‐PPP is designed to retrieve TECM from an array of colocated receivers, taking advantage of the broadcast orbit and clock products. Moreover, A‐PPP also takes into account the fact that the ionospheric effects measured from one satellite to all colocated receivers ought to be the same, thus leading to the estimability of interreceiver DCB. We perform a comparative study of the formal precision and the empirical accuracy of the TECM that are retrieved, respectively, by three methods from the same set of GPS data. Results of such a study can be used to assess the actual performance of the three methods. In addition, we check the temporal stability in A‐PPP‐derived interreceiver DCB estimates over time periods ranging from 1 to 3 days.
Quantifying entrainment in pyroclastic density currents from the Tungurahua eruption, Ecuador: Integrating field proxies with numerical simulations
Authors: Benage M. C. , Dufek J. , Mothes P. A. 
Published: June 2016

AbstractThe entrainment of air into pyroclastic density currents (PDCs) impacts the dynamics and thermal history of these highly mobile currents. However, direct measurement of entrainment in PDCs is hampered due to hazardous conditions and opaqueness of these flows. We combine three‐dimensional multiphase Eulerian‐Eulerian‐Lagrangian calculations with proxies of thermal conditions preserved in deposits to quantify air entrainment in PDCs at Tungurahua volcano, Ecuador. We conclude that small‐volume PDCs develop a particle concentration gradient that results in disparate thermal characteristics for the concentrated bed load (>600 to ~800 K) and the overlying dilute suspended load (~300–600 K). The dilute suspended load has effective entrainment coefficients 2–3 times larger than the bed load. This investigation reveals a dichotomy in entrainment and thermal history between two regions in the current and provides a mechanism to interpret the depositional thermal characteristics of small‐volume but frequently occurring PDCs.
Phase locking between atmospheric convectively coupled equatorial Kelvin waves and the diurnal cycle of precipitation over the Maritime Continent
Authors: Baranowski Dariusz B. , Flatau Maria K. , Flatau Piotr J. , Matthews Adrian J. 
Published: June 2016

AbstractConvectively coupled Kelvin waves (CCKWs) are a major component of the tropical atmospheric circulation, propagating eastward around the equatorial belt. Here we show that there are scale interactions between CCKWs and the diurnal cycle over the Maritime Continent. In particular, CCKW packets that pass a base point in the eastern Indian Ocean at 90°E between 0600 and 0900 UTC subsequently arrive over Sumatra in phase with the diurnal cycle of convection. As the distance between Sumatra and Borneo is equal to the distance traveled by a CCKW in 1 day, these waves are then also in phase with the diurnal cycle over Borneo. Consequently, this subset of CCKWs has a precipitation signal up to a factor of 3 larger than CCKWs that arrive at other times of the day and a 40% greater chance of successfully traversing the Maritime Continent.
SAPS onset timing during substorms and the westward traveling surge
Authors: Mishin Evgeny, V. 
Published: June 2016

AbstractWe present multispacecraft observations in the magnetosphere and conjugate ionosphere of the onset time of subauroral polarization streams (SAPS) and tens of keV ring current injections on the duskside in three individual substorms. This is probably the first unequivocal determination of the substorm SAPS onset timing. The time lag between the SAPS and substorm onsets is much shorter than the gradient‐curvature drift time of ∼10 keV ions in the plasmasphere. It seemingly depends on the propagation time of substorm‐injected plasma from the dipolarization onset region to the plasmasphere, as well as on the SAPS position. These observations suggest that fast onset SAPS and ring current injections are causally related to the two‐loop system of the westward traveling surge.
The sensitivity of water availability to changes in the aridity index and other factors—A probabilistic analysis in the Budyko space
Authors: Gudmundsson L. , Greve P. , Seneviratne S. I. 
Published: June 2016

AbstractOne of the pending questions in the context of global change is whether climatic drivers or other factors have stronger influences on water availability. Here we present an approach that allows to estimate the probability that changes in the aridity index have a larger effect on water availability than equal relative changes in other factors. The analysis builds upon a probabilistic extension of the Budyko framework, which is subject to an analytical sensitivity assessment. The results show that changes in water availability are only dominated by changes in the aridity index in very humid climates. This implies that projected intensifications of aridity in drylands may have less influence on water availability than commonly assumed. Instead, other climatic or nonclimatic factors are dominating. The analysis does hence allow to map regions in which water availability is more sensitive to equal relative changes in either the aridity index or all other factors.
GPS constraints on broad scale extension in the Ethiopian Highlands and Main Ethiopian Rift
Authors: Birhanu Yelebe , Bendick Rebecca , Fisseha Shimeles , Lewi Elias , Floyd Michael , King Robert , Reilinger Robert 
Published: June 2016

AbstractMeasurements from GPS sites spanning the Ethiopian Highlands, Main Ethiopian Rift, and Somali Platform in Ethiopia and Eritrea show that present‐day finite strain rates throughout NE Africa can be approximated at the continent scale by opening on the MER. Most sites in the Ethiopian Highlands are consistent with the motion of the Nubian plate at the level of 1 mm/yr with 95% confidence. However, sites at least as far as 60 km west of the rift show higher velocities relative to the stable Nubian frame of 1–2 mm/yr, requiring a combination of localized and distributed deformation to accommodate the African extensional domain. Off‐rift velocities are consistent with ongoing strain related to either high gravitational potential energy or intrusive magmatism away from midrift magmatic segments either on the western rift margin or within the Ethiopian Highlands, especially when combined with likely rheological differences between the Ethiopian Rift and Highlands. Velocities from the Somali Platform are less well determined with uncertainties and residuals from a Somali frame definition at the level of 2–3 mm/yr but without spatially correlated residuals.
A statistical study of EMIC waves observed by Cluster: 2. Associated plasma conditions
Authors: Allen R. C. , Zhang J.‐C. , Kistler L. M. , Spence H. E. , Lin R.‐L. , Klecker B. , Dunlop M. W. , André M. , Jordanova V. K. 
Published: June 2016

AbstractThis is the second in a pair of papers discussing a statistical study of electromagnetic ion cyclotron (EMIC) waves detected during 10 years (2001–2010) of Cluster observations. In the first paper, an analysis of EMIC wave properties (i.e., wave power, polarization, normal angle, and wave propagation angle) is presented in both the magnetic latitude (MLAT)‐distance as well as magnetic local time (MLT)‐L frames. This paper focuses on the distribution of EMIC wave‐associated plasma conditions as well as two EMIC wave generation proxies (the electron plasma frequency to gyrofrequency ratio proxy and the linear theory proxy) in these same frames. Based on the distributions of hot H+ anisotropy, electron and hot H+ density measurements, hot H+ parallel plasma beta, and the calculated wave generation proxies, three source regions of EMIC waves appear to exist: (1) the well‐known overlap between cold plasmaspheric or plume populations with hot anisotropic ring current populations in the postnoon to dusk MLT region; (2) regions all along the dayside magnetosphere at high L shells related to dayside magnetospheric compression and drift shell splitting; and (3) off‐equator regions possibly associated with the Shabansky orbits in the dayside magnetosphere.
Effects of the interplanetary magnetic field on the location of the open‐closed field line boundary
Authors: Wang C. , Wang J. Y. , Lopez R. E. , Zhang L. Q. , Tang B. B. , Sun T. R. , Li H. 
Published: June 2016

AbstractUsing global magnetohydrodynamic(MHD) simulation, we investigate the effect of the interplanetary magnetic field (IMF) on the location of the open‐closed field line boundary(OCB), in particular the duskside and dawnside OCB and their asymmetry. We first model the typical OCB‐crossing events on 22 October 2001 and 24 October 2002 observed by DMSP. The MHD model presents a good estimate of OCB location under quasi‐steady magnetospheric conditions. We then systemically study the location of the OCB under different IMF conditions. The model results show that the dawnside and duskside OCBs respond differently to IMF conditions when BY is present. An empirical expression describing the relationship between the OCB latitudes and IMF conditions has been obtained. It is found that the IMF conditions play an important role in determining the dawn‐dusk OCB asymmetry, which is due to the magnetic reconnection at the dayside magnetopause. The differences between the dawn and dusk OCB latitudes from MHD predictions are in good agreement with the observations.
The trailing edges of high‐speed streams at 1 AU
Authors: Borovsky Joseph E. , Denton Michael H. 
Published: June 2016

AbstractThe trailing‐edge rarefactions of 54 high‐speed streams at 1 AU are analyzed. The temporal durations of the trailing‐edge rarefactions agree with ballistic calculations based on the observed speeds of the fast and slow wind bounding the rarefactions. A methodology is developed to measure solar‐wind compression and rarefaction using the orientations of solar‐wind current sheets. One focus is to determine the signature that best describes the location of the trailing‐edge stream interface between coronal‐hole‐origin plasma and streamer‐belt‐origin plasma; based on the current‐sheet orientations, on the magnetic‐field strength, on the intensity of the electron strahl, and on the intensity of the negative vorticity, an inflection point in the temporal profile of the solar‐wind velocity is taken as the best indicator of the trailing‐edge stream interface. Computer simulations support this choice. Using superposed‐epoch analysis, the plasma properties and turbulence properties of trailing‐edge rarefactions are surveyed. Whereas the signatures of the coronal‐hole/streamer‐belt (slow‐wind/fast‐wind) boundary in the leading edge (corotating interaction region) stream interface are simultaneous, they are not simultaneous in the trailing edge, with ion‐charge‐state signatures occurring on average 13.7 h prior to the proton entropy signature. It is suggested that differences in the leading and trailing edges of coronal holes on the Sun might account for the differences in the leading and trailing edges of high‐speed streams at 1 AU: the formation timescales, heating timescales, and charge‐state‐equilibration timescales of closed flux loops in the corona might be involved.
Generation of secondary waves arising from nonlinear interaction between the quasi 2 day wave and the migrating diurnal tide
Authors: Nguyen Vu A. , Palo Scott E. , Lieberman Ruth S. , Forbes Jeffrey M. , Ortland David A. , Siskind David E. 
Published: June 2016

AbstractTheory and past observations have provided evidence that atmospheric tides and other global‐scale waves interact nonlinearly to produce additional secondary waves throughout the space‐atmosphere interaction region. However, few studies have investigated the generation region of nonlinearly generated secondary waves, and as a result, the manifestation and impacts of these waves are still poorly understood. This study focuses on the nonlinear interaction between the quasi 2 day wave (2dayW3) and the migrating diurnal tide (DW1), two of the largest global‐scale waves in the atmosphere. The fundamental goals of this effort are to characterize the forcing region of the secondary waves and to understand how it relates to their manifestation on a global scale. First, the Fast Fourier Synoptic Mapping method is applied to Thermosphere Ionosphere Mesosphere Energetics and Dynamics‐Sounding of the Atmosphere using Broadband Emission Radiometry satellite observations to provide new evidence of secondary waves. These results show that secondary waves are only significant above 80 km. The nonlinear forcing for each secondary wave is then computed by extracting short‐term primary wave information from a reanalysis model. The estimated nonlinear forcing quantities are used to force a linearized tidal model in order to calculate numerical secondary wave responses. Model results show that the secondary waves are significant from the upper mesosphere to the middle thermosphere, highlighting the implications for the atmosphere‐space weather coupling. The study also concludes that the secondary wave response is most sensitive to the nonlinear forcing occurring in the lower and middle mesosphere and not coincident with the regions of strongest nonlinear forcing.
Photo/pH dual‐responsive biocompatible poly(methacrylic acid)‐based particles for triggered drug delivery
Authors: Yu Lili , Ren Ning , Yang Kuan , Zhang Miao , Su Li 
Published: June 2016

ABSTRACTA novel dual‐responsive (light and pH) particle based on poly(methacrylic acid), poly(methacrylic acid)–poly[1‐(2‐nitrophenyl)ethane‐1,2‐diyl bis(2‐methylacrylate)]was prepared with the facile method of two‐step homogeneous radical polymerization with methacrylic acid as the monomer and 1‐(2‐nitrophenyl)ethane‐1,2‐diyl bis(2‐methylacrylate) as a photodegradable crosslinker. Photolytic assessments were conducted upon irradiation with a UV lamp; this led to particle disintegration caused by cleavage of the photolabile crosslinking points. The light‐dependent degradation was investigated through particle size changes, absorption spectra variations, surface morphology changes, Fourier transform infrared spectroscopy, and the release of Nile red from the particles after irradiation. The pH dependence of the particle systems induced by the protonation and deprotonation of poly(methacrylic acid) was also confirmed by fluorescence spectroscopy. The triggered release of fluorescein diacetate was investigated to demonstrate that the release behavior in cells was light dependent. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 44003.
Oral mucosal injury caused by mammalian target of rapamycin inhibitors: emerging perspectives on pathobiology and impact on clinical practice
Authors: Peterson Douglas E. , O'Shaughnessy Joyce A. , Rugo Hope S. , Elad Sharon , Schubert Mark M. , Viet Chi T. , Campbell‐Baird Cynthia , Hronek Jan , Seery Virginia , Divers Josephine , Glaspy John , Schmidt Brian L. , Meiller Timothy F. 
Published: June 2016

AbstractIn recent years oral mucosal injury has been increasingly recognized as an important toxicity associated with mammalian target of rapamycin (mTOR) inhibitors, including in patients with breast cancer who are receiving everolimus. This review addresses the state‐of‐the‐science regarding mTOR inhibitor‐associated stomatitis (mIAS), and delineates its clinical characteristics and management. Given the clinically impactful pain associated with mIAS, this review also specifically highlights new research focusing on the study of the molecular basis of pain. The incidence of mIAS varies widely (2–78%). As reported across multiple mTOR inhibitor clinical trials, grade 3/4 toxicity occurs in up to 9% of patients. Managing mTOR‐associated oral lesions with topical oral, intralesional, and/or systemic steroids can be beneficial, in contrast to the lack of evidence supporting steroid treatment of oral mucositis caused by high‐dose chemotherapy or radiation. However, steroid management is not uniformly efficacious in all patients receiving mTOR inhibitors. Furthermore, technology does not presently exist to permit clinicians to predict a priori which of their patients will develop these lesions. There thus remains a strategic need to define the pathobiology of mIAS, the molecular basis of pain, and risk prediction relative to development of the clinical lesion. This knowledge could lead to novel future interventions designed to more effectively prevent mIAS and improve pain management if clinically significant mIAS lesions develop.
A DFT Study of CO2 Hydrogenation on Faujasite‐Supported Ir4 Clusters: on the Role of Water for Selectivity Control
Authors: Szyja Bartłomiej M. , Smykowski Daniel , Szczygieł Jerzy , Hensen Emiel J. M. , Pidko Evgeny A. 
Published: June 2016

AbstractReaction mechanisms for the catalytic hydrogenation of CO2 by faujasite‐supported Ir4 clusters were studied by periodic DFT calculations. The reaction can proceed through two alternative paths. The thermodynamically favoured path results in the reduction of CO2 to CO, whereas the other, kinetically preferred channel involves CO2 hydrogenation to formic acid under water‐free conditions. Both paths are promoted by catalytic amounts of water confined inside the zeolite micropores with a stronger promotion effect for the reduction path. Co‐adsorbed water facilitates the cooperation between the zeolite Brønsted acid sites and Ir4 cluster by opening low‐energy reaction channels for CO2 conversion.
Electro‐optical Properties of Neutral and Radical Ion Thienosquaraines
Authors: Maltese Vito , Cospito Sante , Beneduci Amerigo , De Simone Bruna Clara , Russo Nino , Chidichimo Giuseppe , Janssen René A. J. 
Published: June 2016

AbstractThienosquaraines are an interesting class of electroactive dyes that are useful for applications in organic electronics. Herein, the redox chemistry and electrochromic response of a few newly synthesized thienosquaraines are presented. These properties are compared to those of the commercial 2,4‐bis[4‐(N,N‐diisobutylamino)‐2,6‐dihydroxyphenyl]squaraine. The stability of the radical ions formed in electrochemical processes strongly affects these properties, as shown by cyclic voltammetry, in situ spectroelectrochemistry, and quantum chemical calculations. Furthermore, all of the dyes show aggregation tendency resulting in panchromatic absorption covering the whole UV/Vis spectral range.