bluuebunny/crossref_metadata_2025_split huggingface dataset:
Rotational modulation of Saturn's radio emissions after equinox
Authors: Ye S.‐Y. , Fischer G. , Kurth W. S. , Menietti J. D. , Gurnett D. A. 
Published: November 2016

AbstractSaturn kilometric radiation (SKR), narrowband emission, and auroral hiss are periodically modulated due to Saturn's rotation, and the periods were found to vary with time. We analyze Cassini observations of Saturn's radio emissions with the main focus on the four years 2012–2015. It is shown that the rotation rates of SKR north and south were different since mid‐2012 with SKR north being faster until autumn 2013, followed by a 1 year interval of similar north and south rotation rates and phases, before the northern SKR component finally became slower than the southern SKR in late 2014. The dual rotation rates of 5 kHz narrowband emissions reappeared for slightly longer than 1 year after a long break since equinox. Auroral hiss provides an unambiguous way of tracking the rotation signals from each hemisphere because the whistler mode waves cannot cross the equator. Rotation rates of auroral hiss and narrowband emissions are consistent with each other and those of SKR when they are observed at high latitudes in early 2013. The phase difference between SKR and auroral hiss and the intensity of auroral hiss are local time dependent.
Rate and state frictional and healing behavior of carbonate fault gouge explained using microphysical model
Authors: Chen Jianye , Spiers Christopher J. 
Published: November 2016

AbstractClassical rate‐and‐state friction (RSF) laws are widely applied in modeling earthquake dynamics but generally using empirically determined parameters with little or no knowledge of, or quantitative account for, the controlling physical mechanisms. Here a mechanism‐based microphysical model is developed for describing the frictional behavior of carbonate fault gouge, assuming that the frictional behavior seen in lab experiments is controlled by competing processes of rate‐strengthening intergranular sliding versus contact creep by pressure solution. By solving the controlling equations, derived from kinematic and energy/entropy balance considerations, and employing a microphysical model for rate‐strengthening grain boundary friction plus standard creep equations for pressure solution, we simulate typical lab‐frictional tests, namely, “velocity stepping” and “slide‐hold‐slide” test sequences, for velocity histories and environmental conditions employed in previous experiments. The modeling results capture all of the main features and trends seen in the experimental results, including both steady state and transient aspects of the observed behavior, with reasonable quantitative agreement. To our knowledge, ours is the first mechanism‐based model that can reproduce RSF‐like behavior in terms of microstructurally verifiable processes and state variables. Since it is microphysically based, we believe that our modeling approach can provide an improved framework for extrapolating friction data to natural conditions.
OH* imager response to turbulence‐induced temperature fluctuations
Authors: Gardner Chester S. , Vargas Fabio A. 
Published: November 2016

AbstractThe layer of the excited state hydroxyl radical (OH*) is formed in the mesopause region by the reaction of ozone (O3) and atomic hydrogen (H). We derive the theoretical expressions for the OH* brightness and rotational temperature (T*) responses to high‐frequency atmospheric temperature perturbations. The theory is used to calculate the 1‐D and 2‐D horizontal wave number spectra of the OH* and T* image fluctuations induced by atmospheric turbulence. By applying the theory to images of a breaking gravity wave packet, acquired by the Utah State University Advanced Mesospheric Temperature Mapper, we show that existing infrared OH* imager technology can observe the evolution of gravity wave breakdown and characterize the resulting turbulent eddies in the source region and in the inertial subrange of the turbulence spectrum. For the example presented here, the RMS OH* brightness fluctuations induced by the gravity wave packet was 2.90% and by the associated turbulence was 1.07%. Unfortunately, the T* fluctuations induced by turbulence are usually too small to be observed in the OH* rotational temperature maps.
Using qflux to constrain modeled Congo Basin rainfall in the CMIP5 ensemble
Authors: Creese A. , Washington R. 
Published: November 2016

AbstractCoupled models are the tools by which we diagnose and project future climate, yet in certain regions they are critically underevaluated. The Congo Basin is one such region which has received limited scientific attention, due to the severe scarcity of observational data. There is a large difference in the climatology of rainfall in global coupled climate models over the basin. This study attempts to address this research gap by evaluating modeled rainfall magnitude and distribution amongst global coupled models in the Coupled Model Intercomparison Project 5 (CMIP5) ensemble. Mean monthly rainfall between models varies by up to a factor of 5 in some months, and models disagree on the location of maximum rainfall. The ensemble mean, which is usually considered a “best estimate” of coupled model output, does not agree with any single model, and as such is unlikely to present a possible rainfall state. Moisture flux (qflux) convergence (which is assumed to be better constrained than parameterized rainfall) is found to have a strong relationship with rainfall; strongest correlations occur at 700 hPa in March–May (r = 0.70) and 850 hPa in June–August, September–November, and December–February (r = 0.66, r = 0.71, and r = 0.81). In the absence of observations, this relationship could be used to constrain the wide spectrum of modeled rainfall and give a better understanding of Congo rainfall climatology. Analysis of moisture transport pathways indicates that modeled rainfall is sensitive to the amount of moisture entering the basin. A targeted observation campaign at key Congo Basin boundaries could therefore help to constrain model rainfall.
Monitoring rock freezing and thawing by novel geoelectrical and acoustic techniques
Authors: Murton Julian B. , Kuras Oliver , Krautblatter Michael , Cane Tim , Tschofen Dominique , Uhlemann Sebastian , Schober Sandra , Watson Phil 
Published: November 2016

AbstractAutomated monitoring of freeze‐thaw cycles and fracture propagation in mountain rockwalls is needed to provide early warning about rockfall hazards. Conventional geoelectrical methods such as electrical resistivity tomography (ERT) are limited by large and variable ohmic contact resistances, requiring galvanic coupling with metal electrodes inserted into holes drilled into rock, and which can be loosened by rock weathering. We report a novel experimental methodology that combined capacitive resistivity imaging (CRI), ERT, and microseismic event recording to monitor freeze‐thaw of six blocks of hard and soft limestones under conditions simulating an active layer above permafrost and seasonally frozen rock in a nonpermafrost environment. Our results demonstrate that the CRI method is highly sensitive to freeze‐thaw processes; it yields property information equivalent to that obtained with conventional ERT and offers a viable route for nongalvanic long‐term geoelectrical monitoring, extending the benefits of the methodology to soft/hard rock environments. Contact impedances achieved with CRI are less affected by seasonal temperature changes, the aggregate state of the pore water (liquid or frozen), and the presence of low‐porosity rock with high matrix resistivities than those achieved with ERT. Microseismic monitoring has the advantage over acoustic emissions that events were recorded in relevant field distances of meters to decameters from cracking events. For the first time we recorded about 1000 microcracking events and clustered them in four groups according to frequency and waveform. Compared to previous studies, mainly on ice‐cracking in glaciers, the groups are attributed to single‐ or multiple‐stage cracking events such as crack coalescence.
Poorly ventilated deep ocean at the Last Glacial Maximum inferred from carbon isotopes: A data‐model comparison study
Authors: Menviel L. , Yu J. , Joos F. , Mouchet A. , Meissner K. J. , England M. H. 
Published: November 2016

AbstractAtmospheric CO2 was ∼90 ppmv lower at the Last Glacial Maximum (LGM) compared to the late Holocene, but the mechanisms responsible for this change remain elusive. Here we employ a carbon isotope‐enabled Earth System Model to investigate the role of ocean circulation in setting the LGM oceanic δ13C distribution, thereby improving our understanding of glacial/interglacial atmospheric CO2 variations. We find that the mean ocean δ13C change can be explained by a 378 ± 88 Gt C(2σ) smaller LGM terrestrial carbon reservoir compared to the Holocene. Critically, in this model, differences in the oceanic δ13C spatial pattern can only be reconciled with a LGM ocean circulation state characterized by a weak (10–15 Sv) and relatively shallow (2000–2500 m) North Atlantic Deep Water cell, reduced Antarctic Bottom Water transport (≤10 Sv globally integrated), and relatively weak (6–8 Sv) and shallow (1000–1500 m) North Pacific Intermediate Water formation. This oceanic circulation state is corroborated by results from the isotope‐enabled Bern3D ocean model and further confirmed by high LGM ventilation ages in the deep ocean, particularly in the deep South Atlantic and South Pacific. This suggests a poorly ventilated glacial deep ocean which would have facilitated the sequestration of carbon lost from the terrestrial biosphere and atmosphere.
On the consistency of the SuperDARN radar velocity and E × B plasma drift
Authors: Koustov A. V. , Lavoie D. B. , Varney R. H. 
Published: November 2016

AbstractJoint observations of the Rankin Inlet (RKN) and Inuvik Super Dual Auroral Radar Network (SuperDARN) HF radars and Resolute Bay incoherent scatter radar (RISR) are used to assess consistency in their plasma flow velocity measurements. The analysis covers more than 500 h of successful concurrent measurements. We demonstrate that, overall, the radars show close velocities, although there were minor differences including SuperDARN velocity underestimation, in line with previous publications, and the persistent occurrence of measurements with a SuperDARN velocity magnitude above the RISR velocity magnitude. We argue that, for one event, the velocity overestimation occurs owing to echo detection from a laterally refracted RKN beam while, generally, the effect should be fairly wide‐spread in SuperDARN data because of microstructures with enhanced electron density in the scattering volume that might have either weak irregularities or increased local electric fields. We estimate that the correction of RKN velocity data by considering the effect of the index of refraction improves RKN‐RISR velocity agreement but only for 63% of points. This implies that care should be exercised when attempting to correct raw SuperDARN velocity data by the index of refraction.
Coupled modeling of storm surge and coastal inundation: A case study in New York City during Hurricane Sandy
Authors: Yin Jie , Lin Ning , Yu Dapeng 
Published: November 2016

AbstractIn this paper, we describe a new method of modeling coastal inundation arising from storm surge by coupling a widely used storm surge model (ADCIRC) and an urban flood inundation model (FloodMap). This is the first time the coupling of such models is implemented and tested using real events. The method offers a flexible and efficient procedure for applying detailed ADCIRC storm surge modeling results along the coastal boundary (with typical resolution of ∼100 m) to FloodMap for fine resolution inundation modeling (<5 m). The coastal inundation during Hurricane Sandy was simulated at both the city (New York City) and subregional (lower Manhattan) scales with various resolutions. Results obtained from the ADCIRC and coupled ADCIRC‐FloodMap simulations were compared with the recorded (high water marks) and derived (inundation extent based on the planar method) data from FEMA. At the city scale, coupled ADCIRC‐FloodMap modeling demonstrates improved prediction over ADCIRC modeling alone for both the extent and depth of inundation. The advantage of the coupled model is further illustrated in the subregional modeling, using a mesh resolution of 3 m which is substantially finer than the inland mesh resolution used by ADCIRC (>70 m). In further testing, we explored the effects of mesh resolution and roughness specification. Results agree with previous studies that fine resolution is essential for capturing intricate flow paths and connectivity in urban topography. While the specification of roughness is more challenging for urban environments, it may be empirically optimized. The successful coupling of ADCIRC and FloodMap models for fine resolution coastal inundation modeling unlocks the potential for undertaking large numbers of probabilistically based synthetic surge events for street‐level risk analysis.
Dendritic Spines
Authors: Kirk Lyndsey M , Harris Kristen M 
Published: November 2016

Abstract

Dendritic spines are small protrusions from dendrites that host the majority of excitatory synapses in the central nervous system. Structurally, excitatory synapses located on dendritic spines are asymmetric, with a presynaptic bouton that contains round clear vesicles apposed to a postsynaptic density where glutamate receptors are anchored. Spines form biochemical compartments that can isolate activated signalling pathways that occur at one synapse from those at other synapses, thereby providing a way to enhance the specificity of connections between neurons in the brain. Structural changes of dendritic spines in response to stimulation facilitate changes in synaptic strength, and these changes are likely to underlie important higher brain functions such as learning and memory. Dysregulation of spine morphology is seen in several neurological disorders such as Alzheimer's disease and fragile X syndrome.

Key Concepts

Spines are the primary site of excitatory synapses.

Smooth endoplasmic reticulum can form complex structures localized to large spines.

The cytoskeleton of spines is mostly composed of actin.

Trans‐synaptic adhesion molecules as well as proteins secreted from astroglia help stabilise synapses.

Spines can act as small biochemical compartments.

Spine structure is responsive to activity.
Group additive modeling of substituent effects in monocyclic aromatic hydrocarbon radicals
Authors: Ince Alper , Carstensen Hans‐Heinrich , Sabbe Maarten , Reyniers Marie‐Françoise , Marin Guy B. 
Published: November 2016

The thermodynamic properties of the unsubstituted and substituted phenyl, phenoxy, anisyl, benzoyl, styryl and benzyl radicals with six substituents (hydroxy, methoxy, formyl, vinyl, methyl, and ethyl) are calculated with the bond additivity corrected (BAC) post‐Hartree‐Fock G4 method. Bond dissociation energies of monocyclic aromatic hydrocarbons are calculated and used to identify substituent interactions in these radicals. Benson's Group Additivity (GA) scheme is extended to aromatic radicals by defining 6 GAV and 29 NNI parameters through least squares regression to a database of thermodynamic properties of 369 radicals. Comparison between G4/BAC and GA calculated thermodynamic values shows that the standard enthalpies of formation generally agree within 4 kJ mol−1, whereas the entropies and the heat capacities deviate less than 4 J mol−1 K−1. © 2016 American Institute of Chemical Engineers AIChE J, 63: 2089–2106, 2017
Cognitive control dysfunction in workers exposed to manganese‐containing welding fume
Authors: Al‐Lozi Amal , Nielsen Susan Searles , Hershey Tamara , Birke Angela , Checkoway Harvey , Criswell Susan R. , Racette Brad A. 
Published: November 2016

BackgroundChronic exposure to manganese (Mn) is a health concern in occupations such as welding because of well‐established motor effects due to basal ganglia dysfunction. We hypothesized that cognitive control (the ability to monitor, manipulate, and regulate ongoing cognitive demands) would also be affected by chronic Mn exposure.MethodsWe examined the relationship between Mn exposure and cognitive control performance in 95 workers with varying intensity and duration (median 15.5 years) of exposure to welding fume. We performed linear regression to assess the association between exposure to Mn‐containing welding fume and cognitive control tasks.ResultsOverall performance was inversely related to intensity of welding exposure (P = 0.009) and was driven by the Two‐Back and Letter Number Sequencing tests that assess working memory (both P = 0.02).ConclusionsOccupational exposure to Mn‐containing welding fume may be associated with poorer working memory performance, and workers may benefit from practices that reduce exposure intensity. Am. J. Ind. Med. 60:181–188, 2017. © 2016 Wiley Periodicals, Inc.
Surgical therapy vs continued medical therapy for medically refractory chronic rhinosinusitis: a systematic review and meta‐analysis
Authors: Patel Zara M. , Thamboo Andrew , Rudmik Luke , Nayak Jayakar V. , Smith Timothy L. , Hwang Peter H. 
Published: November 2016

BackgroundThe currently accepted treatment paradigm of treating chronic rhinosinusitis (CRS) first with appropriate medical therapy (AMT) and then with surgery if patients are refractory to AMT, has been criticized for lack of evidence. The objective of this study was to reassess the literature and establish the highest level of evidence possible regarding further management of CRS patients refractory to AMT.MethodsThis study was a systematic review (SR) with meta‐analysis (MA). Adult CRS patients who received AMT and then underwent either medical or surgical therapy in moderate to high level prospective studies were included. Outcomes assessed were disease‐specific quality of life (QOL), nasal endoscopy, health‐state utility, missed work days, change in cardinal symptoms of CRS, economic impact, and adverse events.ResultsA total of 970 manuscripts were identified; 6 studies were ultimately included in the SR with 5 included in the MA. Compared to continued medical therapy, endoscopic sinus surgery (ESS) significantly improved patient‐based QOL scores (p < 0.00001) and nasal endoscopy scores (p < 0.00001). Difference in missed work days depended heavily on patient choice of intervention. Unpooled analysis showed improvements in olfaction, health utility scores, and cost‐effectiveness.ConclusionOn meta‐analysis, for CRS patients refractory to AMT, ESS significantly improves objective endoscopic scoring outcomes vs continued medical therapy alone. In patients with refractory CRS who have significant reductions in baseline QOL, ESS results in significant improvements. Continued medical therapy appears to maintain outcomes in patients with less severe baseline QOL. Unpooled analysis demonstrates improvement in health utility, olfaction, and cost‐effectiveness following ESS compared to continued medical therapy alone, in medically refractory CRS.
Endoscopic nasopharyngectomy in recurrent nasopharyngeal carcinoma: a case series, literature review, and pooled analysis
Authors: Vlantis Alexander C. , Lee Dennis L.Y. , Wong Eddy W.Y. , Chow Samuel M.W. , Ng Siu K. , Chan Jason Y.K. 
Published: November 2016

BackgroundTo critically evaluate the use of endoscopic nasopharyngectomy in the treatment of recurrent nasopharyngeal carcinoma (NPC) through a case series, systematic literature review, and pooled analysis.MethodsA case series of 18 patients combined with systematic literature review and pooled analysis of PubMed, Web of Science, and Scopus search, identifying 576 papers. After excluding 307 papers as search engine duplicates, only 16 of the remaining papers had adequate patient data to be included.ResultsOur case series of 18 patients had a 2‐year disease‐free survival (DFS) and overall survival (OS) of 90.0% and 100%, respectively. The pooled analysis of 300 patients that had an endoscopic resection of recurrent NPC showed recurrence‐free survival and overall survival were 85.8% and 82.9%, respectively. Most, 56.1%, were recurrent T1 lesions. Resection margins were negative in 90.2% of patients. Local recurrence occurred in 20.1% of patients. Major complications occurred in 13.6% of patients. The mean hospital stay was 5.8 days, the mean operating time was 228.3 minutes, and the mean operative blood loss was 163 mL.ConclusionEndoscopic resection of recurrent NPC occurs with low surgical morbidity. However, further long‐term evaluation with longer follow‐up data is needed to evaluate if the survival data is comparable or better than open approaches.
Industrielle Anwendungen von Goldkatalysatoren
Authors: Ciriminna Rosaria , Falletta Ermelinda , Della Pina Cristina , Teles Joaquim Henrique , Pagliaro Mario 
Published: November 2016

AbstractErst kürzlich fanden Goldkatalysatoren den Weg in die ersten großtechnischen industriellen Anwendungen. Dieser Kurzaufsatz bietet eine kritische Analyse der Rahmenbedingungen und Hindernisse auf dem langen Weg von der Entdeckung der katalytischen Eigenschaften von Gold bis zur großtechnischen Anwendung von Goldkatalysatoren. Diese Einblicke sollen Forschern aus Hochschule und Industrie, die heute an der Entwicklung von Goldkatalysatoren arbeiten, helfen, die Probleme von morgen zu bewältigen.
Promoting Difficult Carbon–Carbon Couplings: Which Ligand Does Best?
Authors: Gioria Estefanía , del Pozo Juan , Martínez‐Ilarduya Jesús M. , Espinet Pablo 
Published: November 2016

AbstractA Pd complex, cis‐[Pd(C6F5)2(THF)2] (1), is proposed as a useful touchstone for direct and simple experimental measurement of the relative ability of ancillary ligands to induce C−C coupling. Interestingly, 1 is also a good alternative to other precatalysts used to produce Pd0L. Complex 1 ranks the coupling ability of some popular ligands in the order PtBu3>o‐TolPEWO‐F≈tBuXPhos>P(C6F5)3≈PhPEWO‐F>P(o‐Tol)3≈THF≈tBuBrettPhos≫Xantphos≈PhPEWO‐H≫PPh3 according to their initial coupling rates, whereas their efficiency, depending on competitive hydrolysis, is ranked tBuXPhos≈PtBu3≈o‐TolPEWO‐F>PhPEWO‐F>P(C6F5)3≫tBuBrettPhos>THF≈P(o‐Tol)3>Xantphos>PhPEWO‐H≫PPh3. This “meter” also detects some other possible virtues or complications of ligands such as tBuXPhos or tBuBrettPhos.
Eintopfsynthese ungeschützter anomerer Glykosylthiole in Wasser für Glykan‐Ligationen mit hochfunktionalisierten Zuckern
Authors: Köhling Sebastian , Exner Matthias P. , Nojoumi Saba , Schiller Jürgen , Budisa Nediljko , Rademann Jörg 
Published: November 2016

AbstractDie chemische Synthese von Oligosaccharid‐Konjugaten ist essenziell für ein tieferes Verständnis der Funktionen von Kohlenhydraten. Sie könnte durch effektive Methoden der anomeren Ligation von ungeschützten Zuckern in Wasser deutlich erleichtert werden. Hier stellen wir ein leistungsfähiges Protokoll zur Herstellung anomerer Glykosylthiole von komplexen Mono‐, Di‐, und Oligosacchariden vor. Unter Ausnutzung der Nachbargruppenbeteiligung von 2‐Acetamidozuckern erzeugte 1,2‐Oxazoline wurden durch Zugabe von 1‐Thiosäuren in die entsprechenden Gykosylthioester überführt. Die in situ erzeugten Glykosylthiolate wurden dann mit Michael‐Akzeptoren, aliphatischen Halogeniden und Aziridinen zu vielseitig einsetzbaren Glykokonjugaten umgesetzt. Durch Thiol‐En‐Reaktionen wurden auch Konjugate mit Aminosäuren und Proteinen erhalten. Somit wurde ein effizienter Zugang zu anomeren Glykosylthiolen und Thiolaten geschaffen, der eine anomere Funktionalisierung von komplexen ungeschützten Glykanen in Wasser ermöglicht.