bluuebunny/crossref_metadata_2025_split huggingface dataset:
Submarine groundwater discharge as a possible formation mechanism for permafrost‐associated gas hydrate on the circum‐Arctic continental shelf
Authors: Frederick Jennifer M. , Buffett Bruce A. 
Published: February 2016

AbstractSubmarine groundwater discharge (SGD) is a large‐scale, buoyancy‐driven, offshore flow of terrestrial groundwater. If SGD occurs within the permafrost‐bearing sediments of the circum‐Arctic shelf, such fluid circulation may transport large amounts of dissolved methane to the circum‐Arctic shelf, aiding the formation of permafrost‐associated gas hydrate. We investigate the feasibility of this new permafrost‐associated gas hydrate formation mechanism with a 2‐D, multiphase fluid flow model, using the Canadian Beaufort Shelf as an example. The numerical model includes freeze/thaw permafrost processes and predicts the unsteady, 2‐D methane solubility field for hydrate inventory calculations. Model results show that widespread, low‐saturation hydrate deposits accumulate within and below submarine permafrost, even if offshore‐flowing groundwater is undersaturated in methane gas. While intrapermafrost hydrate inventory varies widely depending on permafrost extent, subpermafrost hydrate stability remains largely intact across consecutive glacial cycles, allowing widespread subpermafrost accumulation over time. Methane gas escape to the sediment surface (atmosphere) is predicted along the seaward permafrost boundary during the early to middle years of each glacial epoch; however, if free gas is trapped within the forming permafrost layer instead, venting may be delayed until ocean transgression deepens the permafrost table during interglacial periods, and may be related to the spatial distribution of observed pingo‐like features (PLFs) on the Canadian Beaufort Shelf. Shallow, gas‐charged sediments are predicted above the gas hydrate stability zone at the midshelf to shelf edge and the upper slope, where a gap in hydrate stability allows free gas to accumulate and numerous PLFs have been observed.
Retrieving co‐occurring cloud and precipitation properties of warm marine boundary layer clouds with A‐Train data
Authors: Mace Gerald G. , Avey Stephanie , Cooper Steven , Lebsock Matthew , Tanelli Simone , Dobrowalski Greg 
Published: February 2016

AbstractIn marine boundary layer (MBL) clouds the formation of precipitation from the cloud droplet distribution in the presence of variable aerosol plays a fundamental role in determining the coupling of these clouds to their environment and ultimately to the climate system. Here the degree to which A‐Train satellite measurements can diagnose simultaneously occurring cloud and precipitation properties in MBL clouds is examined. Beginning with the measurements provided by CloudSat and Moderate Resolution Imaging Spectroradiometer (including a newly available microwave brightness temperature from CloudSat), and a climatology of MBL cloud properties from past field campaigns, an assumption is made that any hydrometeor volume could contain both cloud droplet and precipitation droplet modes. Bayesian optimal estimation is then used to derive atmospheric states by inverting a measurement vector carefully accounting for uncertainties due to instrument noise, forward model error, and assumptions. It is found that in many cases where significant precipitation coexists with cloud, due to forward model error driven by uncertainties in assumptions, the uncertainty in retrieved cloud properties is greater than the variance in the prior climatology. It is often necessary to average several thousand (hundred) precipitating (weakly precipitating) profiles to obtain meaningful information regarding the properties important to microphysical processes. Regardless, if such process level information is deemed necessary for better constraining predictive models of the climate system, measurement systems specifically designed to accomplish such retrievals must be considered for the future.
Assessing spatiotemporal variation of drought in China and its impact on agriculture during 1982–2011 by using PDSI indices and agriculture drought survey data
Authors: Yan Hao , Wang Shao‐Qiang , Wang Jun‐Bang , Lu Hou‐Quan , Guo An‐Hong , Zhu Zai‐Chun , Myneni Ranga B. , Shugart Herman H. 
Published: February 2016

AbstractInspired by concerns of the effects of a warming climate, drought variation and its impacts have gained much attention in China. Arguments about China's drought persist and little work has utilized agricultural drought survey area to evaluate the impact of natural drought on agriculture. Based on a newly revised self‐calibrating Palmer Drought Severity Index (PDSI) model driven with air‐relative‐humidity‐based two‐source (ARTS) E0 (PDSIARTS; Yan et al., 2014), spatial and temporal variations of drought were analyzed for 1982–2011 in China, which indicates that there was nonsignificant change of drought over this interval but with an extreme drought event happened in 2000–2001. However, using air temperature (Ta)‐based Thornthwaite potential evaporation (EP_Th) and Penman‐Monteith potential evaporation (EP_PM) to drive the PDSI model, their corresponding PDSITh and PDSIPM all gave a significant drying trend for 1982–2011. This suggests that PDSI model was sensitive to EP parameterization in China. Annual drought‐covered area from agriculture survey was initially adopted to evaluate impact of PDSI drought on agriculture in China during 1982–2011. The results indicate that PDSIARTS drought area (defined as PDSIARTS < −0.5) correlated well with the agriculture drought‐covered area and PDSIARTS successfully detected the extreme agriculture drought in 2000–2001 during 1982–2011, i.e., climate factors dominated the interannual changes of agriculture drought area, while PDSITh and PDSIPM drought areas had no relationship with the agriculture drought‐covered area and overestimated the uptrend of agriculture drought This study highlights the importance of coupling PDSI with drought survey data in evaluating the impact of natural drought on agriculture.
Decadal variability in PMCs and implications for changing temperature and water vapor in the upper mesosphere
Authors: Hervig Mark E. , Berger Uwe , Siskind David E. 
Published: February 2016

AbstractObservations of polar mesospheric clouds (PMC) from the solar backscatter ultraviolet (SBUV) satellite instruments are used to characterize variability and trends from 1979 to 2014. The SBUV PMC record indicates decadal oscillations during the 1980s and 1990s, which are expected to result from the 11 year solar cycle. This oscillation is absent in the recent decade, however, and we speculate that solar cycle effects at PMC altitudes during the 1980s and 1990s may have been fortuitously amplified by stratospheric warming due to volcanic eruptions which occurred near solar maximum. SBUV trend results are compared with temperature, water vapor, and PMCs from the Mesospheric Ice Microphysics and Transport (MIMAS) model. Both SBUV and the model indicate positive trends in PMC vertically integrated water content (IWC), which increase toward higher latitudes. Using analysis of Solar Occultation for Ice Experiment (SOFIE) observations, the SBUV IWC trends are expressed in terms of the underlying changes in temperature and water vapor in the upper mesosphere. SBUV indicates cooling trends that increase toward higher latitudes (−0.5 ± 0.2 K decade−1 at 77°N), consistent with the MIMAS model and scant observations. SBUV indicates increasing water vapor in the Northern Hemisphere upper mesosphere (0.07 ± 0.03 ppmv decade−1 at 77°N, insignificant in the Southern Hemisphere), with values that are consistent with MIMAS but less than expected due to increasing methane.
Spatial variation in exhumation rates across Ladakh and the Karakoram: New apatite fission track data from the Eastern Karakoram, NW India
Authors: Wallis David , Carter Andrew , Phillips Richard J. , Parsons Andrew J. , Searle Michael P. 
Published: February 2016

AbstractCharacterization of low‐temperature cooling histories and associated exhumation rates is critical for deciphering the recent evolution of orogenic regions. However, these may vary significantly over relatively short distances within orogens. It is pertinent therefore to constrain cooling histories and hence exhumation rates across major tectonic boundaries. We report the first apatite fission track ages from the Karakoram Fault Zone in the Eastern Karakoram range, which forms part of the western margin of the Tibetan Plateau. Ten samples, from elevations of 3477–4875 m, have apatite fission track dates from 3.3 ± 0.3 Ma to 7.4 ± 1.1 Ma. The ages correspond to modeled average erosional exhumation rates of 0.67 + 0.27/−0.18 mm/yr across the Eastern Karakoram. The results are consistent with a trend northward from the Indus suture zone, across the Ladakh terrane and into the Karakoram, in which tectonic uplift associated with crustal thickening increases toward the north, raising elevation and promoting glaciation and generation of extreme relief. As a result, erosion and exhumation rates increase south to north. Present‐day precipitation on the other hand varies little within the study area and on a larger scale decreases southwest to northeast across this portion of the orogen. The Eastern Karakoram results highlight the diverse patterns of exhumation driven by regional variations in tectonic response to collision along the western margin of Tibet.
Mapping land water and energy balance relations through conditional sampling of remote sensing estimates of atmospheric forcing and surface states
Authors: Farhadi Leila , Entekhabi Dara , Salvucci Guido 
Published: February 2016

AbstractIn this study, we develop and apply a mapping estimation capability for key unknown parameters that link the surface water and energy balance equations. The method is applied to the Gourma region in West Africa. The accuracy of the estimation method at point scale was previously examined using flux tower data. In this study, the capability is scaled to be applicable with remotely sensed data products and hence allow mapping. Parameters of the system are estimated through a process that links atmospheric forcing (precipitation and incident radiation), surface states, and unknown parameters. Based on conditional averaging of land surface temperature and moisture states, respectively, a single objective function is posed that measures moisture and temperature‐dependent errors solely in terms of observed forcings and surface states. This objective function is minimized with respect to parameters to identify evapotranspiration and drainage models and estimate water and energy balance flux components. The uncertainty of the estimated parameters (and associated statistical confidence limits) is obtained through the inverse of Hessian of the objective function, which is an approximation of the covariance matrix. This calibration‐free method is applied to the mesoscale region of Gourma in West Africa using multiplatform remote sensing data. The retrievals are verified against tower‐flux field site data and physiographic characteristics of the region. The focus is to find the functional form of the evaporative fraction dependence on soil moisture, a key closure function for surface and subsurface heat and moisture dynamics, using remote sensing data.
Remote monitoring of volumetric discharge employing bathymetry determined from surface turbulence metrics
Authors: Johnson E. D. , Cowen E. A. 
Published: February 2016

AbstractCurrent methods employed by the United States Geological Survey (USGS) to measure river discharge are manpower intensive, expensive, and during high flow events require field personnel to work in dangerous conditions. Indirect methods of estimating river discharge, which involve the use of extrapolated rating curves, can result in gross error during high flow conditions due to extrapolation error and/or bathymetric change. Our goal is to develop a remote method of monitoring volumetric discharge that reduces costs at the same or improved accuracy compared with current methods, while minimizing risk to field technicians. We report the results of Large‐Scale Particle Image Velocimetry (LSPIV) and Acoustic Doppler Velocimetry (ADV) measurements conducted in a wide‐open channel under a range of flow conditions, i.e., channel aspect ratio (B/H = 6.6–31.9), Reynolds number (ReH = 4,950–73,800), and Froude number (Fr = 0.04–0.46). Experiments were carried out for two different channel cross sections (rectangular and asymmetric compound) and two bathymetric roughness conditions (smooth glass and rough gravel bed). The results show that the mean surface velocity normalized by the depth‐averaged velocity (the velocity index) decreases with increasing δ*/H, where δ* is the boundary layer displacement thickness and that the integral length scales, L11,1 and L22,1, calculated on the free‐surface vary predictably with the local flow depth. Remote determination of local depth‐averaged velocity and flow depth over a channel cross section yields an estimate of volumetric discharge.
Palladium‐Catalyzed C(sp3)−H Functionalization at the C3 Position of l‐Pipecolinic Acid Derivatives
Authors: Yu Qun‐Ying , Zhong Hong‐Ming , Sun Wen‐Wu , Zhang Shi‐Jin , Cao Pei , Dong Xiao‐Ping , Qin Hong‐Bo , Liu Ji‐Kai , Wu Bin 
Published: February 2016

AbstractThe study of Pd‐catalyzed arylation, alkoxylation, and acyloxylation reactions at the C3 position of l‐pipecolinic acid derivatives to afford cis‐disubstituted piperidines as single stereoisomers was performed. To demonstrate the utility of the reaction, compound 10, an analogue of (−)‐3S‐3‐PPP (9) that is used as a neuroleptic drug for the treatment of schizophrenia, was synthesized featuring the arylation and radical decarboxylation reactions as key steps.
Putting cryptogenic stroke into perspective
Authors: Tobis Jonathan M. 
Published: February 2016

Key Points

In patients who have a cryptogenic stroke and have their PFO closed, the recurrence rate of “cerebral ischemia” is much greater in patients who are older than 55 years.
Most of these recurrent events (2 strokes and 4TIAs) in the older age group were due to identifiable causes.
These findings corroborate the long‐term results from the RESPECT randomized clinical trial of PFO closure versus medical therapy.
Invasive hemodynamic versus Doppler echocardiographic assessment of aortic stenosis severity
Authors: Feldman Ted , Guerrero Mayra 
Published: February 2016

Key Points

Recent real world comparisons of echo and invasive assessment of transaortic pressure gradients in aortic stenosis often show a poor correlation.
The guideline recommended use of Doppler echo without hemodynamic assessments may not reflect the variability of echo measurements in practice, particularly in unselected patients.
An approach using both echo and invasive data is often used in practice today. The guideline recommended use of echo assessments alone should be critically revisited.
Acute kidney injury after TAVI: Predict, detect, and prevent
Authors: Belardi Jorge A. , Albertal Mariano 
Published: February 2016

Key Points

Acute kidney injury (AKI) is frequently observed immediately after transcatheter aortic valve implantation (TAVI).
Both classifications, the RIFLE (the Risk, Injury, Failure, Loss, and End‐stage Kidney) and the KDIGO (Kidney Disease: Improving Global Outcomes) from the VARC‐2 (Valve Academic Research Consortium‐2) are fairly interchangeable and performed well as clinical predictors of all‐cause mortality.
Patients with baseline reduced glomerular filtration rate (GFR) or known atherosclerotic arterial disease are at increased risk of AKI.
Double cerebral embolic protection: Is more less?
Authors: Safian Robert D. 
Published: February 2016

Key Points

During carotid artery stenting (CAS), atheroemboli may arise from the aorta, arch, and ipsilateral carotid artery.
Embolic protection devices (EPD) are designed to decrease the risk of stroke resulting from atheroembolization from the ipsilateral carotid artery during CAS; double (proximal and distal) EPDs may decrease the risk of stroke in high‐risk patients and lesions.
Further studies are needed to determine if double EPDs are superior to single EPDs or other devices.
Transcatheter valve implantation for calcific mitral valve disease
Authors: Webb John G. , Dvir Danny 
Published: February 2016

Key Points

Transcatheter treatment of calcific mitral valve disease with commercially available balloon‐expandable valves is feasible
Current clinical outcomes are suboptimal, consequently this should be considered only in severely symptomatic patients without other options
Purpose‐specific mitral valves may allow for this therapy to achieve its full potential
The evolving features of Nicolaides–Baraitser syndrome – a clinical report of a 20‐year follow‐up
Authors: Ejaz Resham , Babul‐Hirji Riyana , Chitayat David 
Published: February 2016

Key Clinical MessageNicolaides–Baraitser syndrome (NCBRS) is a rare genetic condition associated with SMARCA2 gene mutations. Clinical diagnosis is challenging as its features evolve with time. The 20 years follow‐up of our NCBRS patient, with a previously unreported SMARCA2 mutation, illustrates the syndrome's natural history and its clinical variability, especially in a milder form.
Radical‐Induced Hydrosilylation Reactions for the Functionalization of Two‐Dimensional Hydride Terminated Silicon Nanosheets
Authors: Helbich Tobias , Lyuleeva Alina , Höhlein Ignaz M. D. , Marx Philipp , Scherf Lavinia M. , Kehrle Julian , Fässler Thomas F. , Lugli Paolo , Rieger Bernhard 
Published: February 2016

AbstractHerein we present the functionalization of freestanding silicon nanosheets (SiNSs) by radical‐induced hydrosilylation reactions. An efficient hydrosilylation of Si−H terminated SiNSs can be achieved by thermal initiation or the addition of diazonium salts with a variety of alkene or alkyne derivatives. The radical‐induced hydrosilylation is applicable for a wide variety of substrates with different functionalities, improving the stability and dispersibility of the functional SiNSs in organic solvents and potentially opening up new fields of application for these hybrid materials.
Synthesis of Ammonia Borane Nanoparticles and the Diammoniate of Diborane by Direct Combination of Diborane and Ammonia
Authors: Song Yuanzhou , Ma Nana , Ma Xiaohua , Fang Fang , Chen Xuenian , Guo Yanhui 
Published: February 2016

AbstractPure nanoparticle ammonia borane (NH3BH3, AB) was first prepared through a solvent‐free, ambient‐temperature gas‐phase combination of B2H6 with NH3. The prepared AB nanoparticle exhibits improved dehydrogenation behavior giving 13.6 wt. % H2 at the temperature range of 80–175 °C without severe foaming. Ammonia diborane (NH3BH2(μ‐H)BH3, AaDB) is proposed as the intermediate in the reaction of B2H6 with NH3 based on theoretical studies. This method can also be used to prepare pure diammoniate of diborane ([H2B(NH3)2][BH4], DADB) by adjusting the ratio and concentration of B2H6 to NH3.
Highly Stereoselective [3+2] Cycloadditions of Chiral Palladium‐Containing N1‐1,3‐Dipoles: A Divergent Approach to Enantioenriched Spirooxindoles
Authors: Li Tian‐Ren , Cheng Bei‐Yi , Fan Si‐Qi , Wang Ya‐Ni , Lu Liang‐Qiu , Xiao Wen‐Jing 
Published: February 2016

AbstractA catalytic asymmetric [3+2] cycloaddition reaction of chiral palladium‐containing N1‐1,3‐dipoles with methyleneindolinones has been successfully developed. The reaction allows an efficient construction of 3,3′‐pyrrolinyl spirooxindoles with high yields and excellent stereoselectivities (up to 93 % yield, 19:1 d.r. and >99 % ee). A synthetic application of this methodology is demonstrated and a stereocontrol mechanism is proposed.
ChemInform Abstract: ABSORPTIONSSPEKTREN VON CU(2+)‐IONEN IN WAESSRIGER LOESUNG UND IN VERSCHIEDENEN ORGANISCHEN LOESUNGSMITTELN
Authors: CHHONKAR N. S. 
Published: February 2016

AbstractDie Absorptionsspektren von Cu" in CuCl2 in etwa 12 organischen Lösungsmitteln werden über den Bereich von 10000 bis 3900 Å untersucht.
ChemInform Abstract: ZUSTANDSSELEKTION POLARER MOLEKUELE DURCH WECHSELGRADIENT‐FOKUSSIERUNG
Authors: GUENTHER F. , SCHUEGERL K. 
Published: February 2016

AbstractEin elektrisches Wechselgradient‐Fokussiersystem wird beschrieben, mit dem die Selektion von polaren, zweiatomigen Molekülen in Rotationszuständen möglich ist.
ChemInform Abstract: OSTWALDSCHE REIFUNG KRISTALLINER NIEDERSCHLAEGE IN WAESSRIGEN LOESUNGEN BEI KONSTANTER TEMPERATUR UND PERIODISCHEN TEMPERATURAENDERUNGEN
Authors: HOHMANN H. H. , KAHLWEIT M. 
Published: February 2016

AbstractDie Ostwald‐Reifung kristalliner Niederschläge in wäßrigen Lösungen wird an den Beispielen H2O‐NaNO3 und H2O‐Tetraäthylammoniumjodid untersucht.
ChemInform Abstract: Phasenverhalten im System Sm‐B
Authors: SOLOVYEV G. I. , SPEAR K. E. 
Published: February 2016

AbstractDie Phasengleichgewichte im System Sm‐B wurden röntgenographisch und metallographisch untersucht und die Phasen SmBx (x: 2,0 ± 0,6), SmB4, SmB6 und SmB66 nachgewiesen.
ChemInform Abstract: ELEKTROCHEMIE IN PROPYLENCARBONAT 3. MITT. BESTIMMUNG DER NORMALPOTENTIALE DER ALKALIMETALLE UND DES CALCIUMS, SOLVATATION DER KATIONEN
Authors: L'HER MAURICE , COURTOT‐COUPEZ JACQUELINE 
Published: February 2016

AbstractDie polarographische Reduktion der Alkalimetallkationen (außer Li) ist in Propylencarbonat reversibel.
ChemInform Abstract: POTENTIALABHAENGIGKEIT VON ELEKTROSORPTIONSGLEICHGEWICHTEN UND DIE ELEKTROSORPTIONSWERTIGKEIT GAMMA
Authors: VETTER K. J. , SCHULTZE J. W. 
Published: February 2016

AbstractDie Elektrosorption, d.h. die Adsorption in der inneren Helmholtz‐Schicht an der Phasengrenze Elektrode/Elektrolyt wird in Abhängigkeit von der Potentialdifferenz in der starren Doppelschicht behandelt.
ChemInform Abstract: STROMFLUSS BEI ELEKTROSORPTIONSPROZESSEN UND ELEKTROSORPTIONSWERTIGKEIT GAMMA
Authors: VETTER K. J. , SCHULTZE J. W. 
Published: February 2016

AbstractDie Elektrokapillargleichung wird für Elektrosorptionsreaktionen unter Abtrennung der Effekte der diffusen Doppelschicht in Abhängigkeit von der Potentialdifferenz der starren Doppelschicht bzw. bei Fremdelektrolytüberschuß in Abhängigkeit vom Elektrodenpotential behandelt.
ChemInform Abstract: ABHAENGIGKEIT DER STROEMUNGSRICHTUNG VON DER BESCHAFFENHEIT DES ELEKTROLYTS BEI DER WECHSELSTROMELEKTROOSMOSE
Authors: LASZLO Z. 
Published: February 2016

AbstractSind bei der Wechselstromelektroosmose die Porendurchmesser des Diaphragmas groß genug (40 um), so fließt die Lösung, unabhängig von der Beschaffenheit des Elektrolyts, immer zum Lösungsmittel hinüber.
ChemInform Abstract: EINFLUSS DER ANISOTROPIE UND VON WASSERDAMPF AUF DIE RK. VON CAO UND BETA‐QUARZ IM FESTEN ZUSTAND
Authors: BURTE ARVIND S. , NICHOLSON PATRICK S. 
Published: February 2016

AbstractDie Kinetik der Festkörperreaktion von CaO mit β‐SiO2 wurde bei 1000‐1 200°C in feuchtem und trocknem N2 untersucht.
ChemInform Abstract: DARST. DES ERSTEN OXIDS VON TETRASCHWEFELTETRANITRID
Authors: ROESKY HERBERT W. , PETERSEN OLAF 
Published: February 2016

AbstractDie Titelverbindung (I) wurde durch Reaktion von N,N′‐Bis‐[trimethylsilyl]‐ schwefeldiimid mit dem Anhydrid der Fluoroschwefelsäure unter Abspaltung von Trimethylfluorsilan und Trimethylsilylfluorosulfat erhalten.
ChemInform Abstract: BEARBEITBARE GLASIG‐KERAMISCHE MATERIALIEN AUF DER BASIS EINES TETRASILICAT‐GLIMMERS
Authors: GROSSMAN DAVID G. 
Published: February 2016

AbstractGläser mit eingelagerter kristalliner Tetrasilicat‐Glimmerphase werden beim Erhitzen von KzO‐MgO‐MgFz‐SiOz‐Gläsern auf ca. 940°C erhalten.
ChemInform Abstract: CHEMISCHE METHODE ZUR HERST. DES SPINELLS MGAL2O4
Authors: MITCHELL P. W. D. 
Published: February 2016

AbstractDurch Mischen stöchiometrischer Mengen einer wäßrigen A12(OH)5Cl‐Lösung mit einer Mg(OH)2‐Suspension in H2O wird ein Gel erhalten, das nach Trocknen und Erhitzen auf 900°C ein weißes, partiell kristallines Pulver des Spinells MgA12O4 ergibt.