bluuebunny/crossref_metadata_2025_split huggingface dataset:
Storm time enhancements of 630.0 nm airglow associated with polar cap patches
Authors: Sakai J. , Hosokawa K. , Taguchi S. , Ogawa Y. 
Published: February 2014

AbstractWe examined the brightness of 630.0 nm airglow, I630, associated with polar cap patches observed during a magnetic storm that occurred on 22 January 2012. Brightness was measured using an all‐sky imager (ASI) located at Longyearbyen, Svalbard. The observed I630 was compared with the F region electron density observed by the European Incoherent Scatter Svalbard Radar (ESR). The I630 was positively correlated with the F2 layer peak electron density, NmF2, and inversely correlated with the altitude of the F2layer peak electron density, hmF2, as expected from the known relationship between these parameters. To estimate the altitude of the peak emission of the airglow, we performed model calculations of the volume emission rate, V630, under quiet and disturbed conditions, using Mass Spectrometer Incoherent Scatter modeled neutral gas profiles and the electron density profile obtained from the ESR data. In order to validate the V630 calculation, I630 was calculated by integrating the V630 along altitude and then compared with the ASI‐observed I630. During the observation periods the measured brightness frequently exceeded the calculated I630; we infer that in most cases, low‐energy particle precipitation is responsible for the extra brightness. However, when there was less particle precipitation, the observed values were in good agreement with the calculated values. Under the magnetically disturbed conditions during our observations, the model calculation showed that the altitude of V630 peak increases, the thickness of the emission layer increases, and patch brightness increases.
Generation of ion cyclotron waves in the corona and solar wind
Authors: Omidi N. , Isenberg P. , Russell C. T. , Jian L. K. , Wei H. Y. 
Published: February 2014

AbstractTo examine the generation and nonlinear evolution of ion cyclotron waves in the corona and solar wind, we perform electromagnetic simulations using a wide range of plasma conditions and ion velocity distribution functions. The source of the instability is temperature anisotropy of ions with temperature perpendicular to the magnetic field larger than parallel. For velocity distribution we use Maxwellian, bi‐Maxwellian, and Fermi‐accelerated functions with perpendicular temperature larger than parallel with the aim to understand the extent to which the details of the distribution function impact the general properties and the nonlinear evolution of the instability. The results show that in a proton‐electron plasma, ion cyclotron waves are generated over a wide range of temperature anisotropies and plasma beta. Also, the general properties of the instability and the nonlinear evolution of the waves are not sensitive to the details of the velocity distribution functions. Allowing for the presence of minor ion species we show that these ions by themselves can drive the instability and generate waves with frequencies below the gyrofrequency of the minor ions. In the event that protons also have temperature anisotropy, waves on the proton branch are also generated. Results using bi‐Maxwellian or Fermi‐accelerated velocity distribution functions show similar properties for the instability and the nonlinear evolution of the waves. However, differences are found when allowing for relative drifts between the protons and minor ions in that when using Fermi‐accelerated distribution functions oblique ion cyclotron waves are generated that are not observed in simulations using bi‐Maxwellian distribution function.
Bimodal size of Jupiter's magnetosphere
Authors: McComas D. J. , Bagenal F. , Ebert R. W. 
Published: February 2014

AbstractObservations of Jovian magnetopause crossing by a number of different spacecraft have established that Jupiter's magnetosphere has a generally bimodal size distribution, with typical standoff distances at the nose of ~63 and ~92 RJ. Here we examine both the external solar wind structure and time constants and the internal magnetospheric time constants for shedding and refilling material in the Jovian plasma disk. We show that these latter time constants are ~ hours to ~10 h, comparable to the compression time of the magnetopause, but shorter than the typically several day expansion time when the solar wind dynamic pressure decreases. Together, we show that it is the well‐developed compressions and rarefactions in the solar wind at ~5 AU that produced the generally bimodally structured solar wind dynamic pressure and hence Jovian magnetospheric size.
Paleomagnetic evidence for a post‐Eocene 90° CCW rotation of internal Apennine units: A linkage with Corsica‐Sardinia rotation?
Authors: Caricchi Chiara , Cifelli Francesca , Sagnotti Leonardo , Sani Federico , Speranza Fabio , Mattei Massimo 
Published: February 2014

AbstractWe report on an extensive paleomagnetic study (36 sites) of the Tuscan Nappe succession from the Northern Apennines Arc, aimed to reconstruct the tectonic evolution of the internal sector of this chain. We analyzed Eocene pelagic foreland ramp deposits (Scaglia Toscana Formation) and Oligocene–lower Miocene siliciclastic turbidites (Macigno and Falterona Formations). Paleomagnetic results show that the internal sector of the Northern Apennines underwent large counterclockwise (CCW) rotations with respect to the Adria‐Africa foreland. A decrease in the rotation magnitude was observed from the southern to the northern sector of the arc (from 91 to 36°). This trend is opposite to that observed in the more external units of Northern Apennines and demonstrates that the oroclinal bending model, which has been proposed for the external units of the chain, is not appropriate to explain the evolution of the internal sector of the arc. On the basis of the observed paleomagnetic pattern, we propose a new tectonic model in which the Tuscan and Falterona‐Cervarola units in the southern area were first rotated CCW along with the Corsica‐Sardinia block during its lower Miocene rotational drifting and were later involved in the main phases of rotational emplacement and translation toward the outermost sector (Umbria domain), thus yielding the final curved shape of the Northern Apennines chain. Data from this study represent the first paleomagnetic evidence of the influence of the Corsica‐Sardinia CCW rotation in the Apennines orogenic wedge deformation, in the general framework of the geodynamic evolution of the Central Mediterranean subduction system.
Adsorption and capillary condensation in porous media as a function of the chemical potential of water in carbon dioxide
Authors: Heath Jason E. , Bryan Charles R. , Matteo Edward N. , Dewers Thomas A. , Wang Yifeng , Sallaberry Cédric J. 
Published: February 2014

AbstractThe chemical potential of water may play an important role in adsorption and capillary condensation of water under multiphase conditions at geologic CO2 storage sites. Injection of large volumes of anhydrous CO2 will result in changing values of the chemical potential of water in the supercritical CO2 phase. We hypothesize that the chemical potential will at first reflect the low concentration of dissolved water in the dry CO2. As formation water dissolves into and is transported by the CO2 phase, the chemical potential of water will increase. We present a pore‐scale model of the CO2‐water interface or menisci configuration based on the augmented Young‐Laplace equation, which combines adsorption on flat surfaces and capillary condensation in wedge‐shaped pores as a function of chemical potential of water. The results suggest that, at a given chemical potential for triangular and square pores, liquid water saturation will be less in the CO2‐water system under potential CO2 sequestration conditions relative to the air‐water vadose zone system. The difference derives from lower surface tension of the CO2‐water system and thinner liquid water films, important at pore sizes <1 × 10−6 m, relative to the air‐water system. Water movement due to capillary effects will likely be minimal in reservoir rocks, but still may be important in finer grained, clayey caprocks, where very small pores may retain water and draw water back into the system via adsorption and capillary condensation, if dry‐out and then rewetting were to occur.
Heat flux modifications related to climate‐induced warming of large European lakes
Authors: Fink Gabriel , Schmid Martin , Wahl Bernd , Wolf Thomas , Wüest Alfred 
Published: February 2014

AbstractWithin the last decades, the water temperature of several European lakes has risen. It is assumed that these temperature increases are due to a reconfiguration of the heat‐balance components. This study explores the dominant modifications of heat exchange with the atmosphere and their temporal evolutions. The objective is to identify the primary changes in heat fluxes and the sequence of events of the reconfiguration for the period 1984–2011. For this purpose, a model was applied to Lake Constance to estimate the contributions of the individual heat fluxes to the total heat balance. The results show that increasing absorption of solar radiation (+0.21 ± 0.13 W m−2 yr−1) and of longwave radiation (+0.25 ± 0.11 W m−2 yr−1) was responsible for the lake surface warming of 0.046 ± 0.011°C yr−1. Heat losses to the atmosphere by longwave emission (−0.24 ± 0.06 W m−2 yr−1) and by latent heat flux (−0.27 ± 0.12 W m−2 yr−1) have intensified in parallel due to higher lake surface temperatures. The heat budget is in a quasi‐steady state, whereas incoming solar radiation and the warmer atmosphere increased the lake surface temperature; the warmer surface emits more longwave radiation and more water is evaporated. At each level of the slowly increasing water temperature, the heat fluxes are balanced. The overall change of the total heat content, however, is relatively little. Although the cooling effect of inflowing rivers decreased, this contribution is also small.
The pace of East African monsoon evolution during the Holocene
Authors: Weldeab Syee , Menke Valerie , Schmiedl Gerhard 
Published: February 2014

AbstractAfrican monsoon precipitation experienced a dramatic change in the course of the Holocene. The pace with which the African monsoon shifted from a strong early to middle to a weak late Holocene is critical for our understanding of climate dynamics, hydroclimate‐vegetation interaction, and shifts of prehistoric human settlements, yet it is controversially debated. On the basis of planktonic foraminiferal Ba/Ca time series from the eastern Mediterranean Sea, here we present a proxy record of Nile River runoff that provides a spatially integrated measure of changes in East African monsoon (EAM) precipitation. The runoff record indicates a markedly gradual middle to late Holocene EAM transition that lasted over 3500 years. The timing and pace of runoff change parallels those of insolation and vegetation changes over the Nile basin, indicating orbitally forced variation of insolation as the main EAM forcing and the absence of a nonlinear precipitation‐vegetation feedback. A tight correspondence between a threshold level of Nile River runoff and the timing of occupation/abandonment of settlements suggests that along with climate changes in the eastern Sahara, the level of Nile River and intensity of summer floods were likely critical for the habitability of the Nile Valley (Egypt).
Promoting Fresh Produce: A Losing Battle?
Authors: McLaughlin Edward W. , Kaiser Harry M. , Rickard Bradley J. 
Published: February 2014

ABSTRACTPrevious research indicates that returns to agricultural producers from generic promotion of their products are substantial. Yet, despite public policy interest in increasing consumption of fruits and vegetables, the United States produce industry has not embraced industry wide promotion. We conduct a survey to better understand stakeholder opinion of a proposed promotion program, and to examine how changes in program design might influence support. Econometric results indicate that support would increase if specific promotion examples were provided, if evidence of likely profitability was clear and if substantial government matching funds were available. Policy implications, including the importance of appropriate target audience and clear communication of program features, are suggested.
The return of the jedi: comparison of the outcomes of endolaser dacryocystorhinostomy and endonasal dacryocystorhinostomy
Authors: Zengin Mehmet Özgür , Eren Erdem 
Published: February 2014

BackgroundExternal dacryocystorhinostomy (DCR) is considered to be the gold standard treatment of primary acquired nasolacrimal duct obstruction. A better understanding of the endoscopic anatomy of the lacrimal sac has increased the success rate of endonasal DCR. Laser DCR has become popular in recent years and has a success rate comparable with those of other endonasal techniques. The aim of this study was to compare the surgical results of endonasal DCR (EDCR) and endonasal laser DCR (ELDCR).MethodsFifty‐four patients treated with ELDCR and 42 patients treated with EDCR for nasolacrimal duct obstruction from 2009 to 2012 with at least 1.5 years of follow‐up were retrospectively enrolled in this comparative study. Lack of patient complaints and irrigation testing were used as subjective and objective assessment tools, respectively.ResultsBoth groups were similar in terms of age and sex. ELDCR had a success rate of 85.2%, and EDCR had a success rate of 92.9%. The difference between the 2 procedures was not statistically significant. ELDCR had a significantly shorter operative time than did EDCR (16.9 vs 24.4 minutes, respectively; p < 0.001).ConclusionEndonasal procedures have the advantage of no scar formation and do not disturb the pumping mechanism of the lacrimal sac. Their success rates are comparable with those of external DCR. Surgery is quicker, and with use of a laser, even less time is spent in the operating room. In selected cases, ELDCR can be a good alternative method with a high success rate.
Synthesis of Highly Substituted 3‐Formylfurans by a Gold(I)‐Catalyzed Oxidation/1,2‐Alkynyl Migration/Cyclization Cascade
Authors: Wang Tao , Shi Shuai , Hansmann Max M. , Rettenmeier Eva , Rudolph Matthias , Hashmi A. Stephen K. 
Published: February 2014

Abstract3‐Formylfuran derivatives are core structures of a variety of bioactive natural products. However, procedures for their preparation are still rare and generally inefficient in terms of atom economy: These methods require multiple steps or harsh reaction conditions and show selectivity problems. An efficient gold(I)‐catalyzed cascade reaction that leads to 3‐formylfurans from easily accessible starting materials is now described. A wide variety of 3‐formylfurans were obtained from the corresponding symmetric and unsymmetric 1,4‐diyn‐3‐ols in the presence of an N‐oxide in good to excellent yields. Isotope‐labeling experiments as well as DFT calculations support a mechanism in which, after an initial oxygen transfer, a 1,2‐alkynyl migration is favored over a hydride shift; a cyclization ensues to afford the desired functionalized furan core.
A Visualizable Chain‐Terminating Inhibitor of Glycosaminoglycan Biosynthesis in Developing Zebrafish
Authors: Beahm Brendan J. , Dehnert Karen W. , Derr Nicolas L. , Kuhn Joachim , Eberhart Johann K. , Spillmann Dorothe , Amacher Sharon L. , Bertozzi Carolyn R. 
Published: February 2014

AbstractHeparan sulfate (HS) and chondroitin sulfate (CS) glycosaminoglycans (GAG) are proteoglycan‐associated polysaccharides with essential functions in animals. They have been studied extensively by genetic manipulation of biosynthetic enzymes, but chemical tools for probing GAG function are limited. HS and CS possess a conserved xylose residue that links the polysaccharide chain to a protein backbone. Here we report that, in zebrafish embryos, the peptide‐proximal xylose residue can be metabolically replaced with a chain‐terminating 4‐azido‐4‐deoxyxylose (4‐XylAz) residue by administration of UDP‐4‐azido‐4‐deoxyxylose (UDP‐4‐XylAz). UDP‐4‐XylAz disrupted both HS and CS biosynthesis and caused developmental abnormalities reminiscent of GAG biosynthesis and laminin mutants. The azide substituent of protein‐bound 4‐XylAz allowed for rapid visualization of the organismal sites of chain termination in vivo through bioorthogonal reaction with fluorescent cyclooctyne probes. UDP‐4‐XylAz therefore complements genetic tools for studies of GAG function in zebrafish embryogenesis.
Controlling Covalent Connection and Disconnection with Light
Authors: Göstl Robert , Hecht Stefan 
Published: February 2014

AbstractThe on‐going need for feature miniaturization and the growing complexity of structures for use in nanotechnology demand the precise and controlled formation of covalent bonds at the molecular level. Such control requires the use of external stimuli that offer outstanding spatial, temporal, as well as energetic resolution. Thus, photoaddressable switches are excellent candidates for creating a system that allows reversible photocontrol over covalent chemical connection and disconnection. Here we show that the formation of covalent bonds between two reagents and their scission in the resulting product can be controlled exclusively by illumination with differently colored light. A furyl‐substituted photoswitchable diarylethene was shown to undergo a reversible Diels–Alder reaction with maleimide to afford the corresponding Diels–Alder adduct. Our system is potentially applicable in any field already relying on the benefits of reversible Diels–Alder reactions.
Magneto‐convection in a rotating layer of nanofluid
Authors: Yadav Dhananjay , Bhargava R. , Agrawal G. S. , Hwang Gyeong S. , Lee Jinho , Kim M. C. 
Published: February 2014

ABSTRACTThe combined effect of rotation and magnetic field on the onset of convection in a horizontal layer of electrically conducting nanofluid is studied. Three cases of free–free, rigid–free, and rigid–rigid boundaries are considered. The two important effects of Brownian motion and thermophoresis are included in the model of nanofluid. The linear stability theory is employed, and the resulting eigenvalue problem is solved analytically for free–free boundaries and numerically for rigid–free and rigid–rigid boundaries using the Galerkin technique. Numerical results are presented for alumina–water nanofluid. The effects of magnetic field, rotation, and various nanofluid parameters such as nanoparticle Rayleigh number, modified diffusive ratio, and Lewis number on the onset of convection are analyzed, and results are depicted graphically. It is found that the critical Rayleigh number is lower for nanofluid in comparison with the regular fluid at the same values of Chandrasekhar number and Taylor number. The sufficient condition for the non‐existence of overstability is also obtained. © 2014 Curtin University of Technology and John Wiley & Sons, Ltd.
Synergy, Compatibility, and Innovation: Merging Lewis Acids with Stereoselective Enamine Catalysis
Authors: Gualandi Andrea , Mengozzi Luca , Wilson Claire M. , Cozzi Pier Giorgio 
Published: February 2014

AbstractIn recent years there has been an accelerated rate of development in the field of organocatalysis, with asymmetric organocatalysis now reaching full maturity. The invention of new organocatalytic reactions and the exploration of new concepts now appear in tandem with the application of organocatalytic techniques in the synthesis of natural products and active pharmaceutical ingredients (APIs). After a “golden rush” in organocatalysis, researchers are now starting to combine different methods, thereby taking advantage of the significant benefits of synergy. Metals are used in combination with organocatalytic processes, thus reaching complexity that is found in nature, where enzymes take advantage of the presence of certain metals to increase the arsenal of organic transformations available. In this Focus review, we illustrate the possibility of a “happy marriage” between Lewis acids and organocatalytic stereoselective processes. Questions have been raised about the combination of Lewis acids and organocatalysis owing to the presence of water and/or strong bases in these processes. Some Lewis acids have been shown to be compatible with organocatalysis and concepts relating to their use will be illustrated herein. To summarize the fruitful use of Lewis acids in stereoselective organocatalytic processes, we will draw attention to the advantages and selectivity achieved using this method.
Remote Impacts of Methyl Substituents on the Guest‐Binding Ability of Self‐Assembled Cages
Authors: Fang Yu , Murase Takashi , Fujita Makoto 
Published: February 2014

AbstractWe synthesized self‐assembled coordination cages in which 1,10‐phenanthroline derivatives serve as capping ligands. Substituents at the 2,9‐positions of the phenanthroline ligand covered the outside of the cage but had an impact on the guest binding inside the cage. Introduction of methyl groups at the 2,9‐positions allowed the cage to accommodate tetraphenylsilane. Bulky mesityl groups overhanging the cage framework significantly shrunk the cage cavity through π–π interactions with the aromatic panels of the cage. The p‐methyl group of the mesityl substituent was a determinant of the restricted motion of 4,4′‐dimethoxybenzil inside the cage at high temperature. Thus, the presence or absence of one methyl group, which is far from the guest‐binding site, makes a significant difference in the guest species and motions inside the cage.
Synchronization of Interconnected Multi‐valued Logical Networks
Authors: Meng Min , Feng Jun‐e , Hou Zhongsheng 
Published: February 2014

AbstractThis paper studies the synchronization of interconnectedk‐valued logical networks, as well as that of interconnected higher orderk‐valued logical networks, based on their algebraic representations. For interconnectedk‐valued logical networks, one necessary and sufficient criterion of synchronization is established via the definition of synchronization and another equivalent condition is given by combining synchronization with fixed points and cycles. Furthermore, with some special properties of semi‐tensor product, the third necessary and sufficient condition for synchronization of interconnectedk‐valued logical networks is raised in terms of transition matrices. Then, the limit set method can be used to analyze the synchronization of interconnected higher orderk‐valued logical networks. Finally, three examples, including the Boolean model for interconnected biochemical oscillators in the cell cycle, are presented to illustrate effectiveness of the results.
Robust Ensemble Kalman Filter Based on Exponential Cost Function
Authors: Bhaumik Shovan 
Published: February 2014

AbstractThis paper provides an alternative point of view to the robust estimation technique for nonlinear non Gaussian systems based on exponential quadratic cost function. The proposed method, named the risk sensitive ensemble Kalman filter (RSEnKF), is based on the ensemble Kalman filter (EnKF) which may be thought of as a Monte Carlo implementation of the Kalman filter for nonlinear estimation problems. The theory and formulation of the RSEnKF are presented in this paper. The proposed method is superior to the extended risk sensitive filter (ERSF) and the quadrature based risk sensitive filters in terms of estimation accuracy, and is faster than the risk sensitive particle filter (RSPF).