bluuebunny/crossref_metadata_2025_split huggingface dataset:
Uncertainties in the attribution of greenhouse gas warming and implications for climate prediction
Authors: Jones Gareth S. , Stott Peter A. , Mitchell John F. B. 
Published: June 2016

AbstractUsing optimal detection techniques with climate model simulations, most of the observed increase of near‐surface temperatures over the second half of the twentieth century is attributed to anthropogenic influences. However, the partitioning of the anthropogenic influence to individual factors, such as greenhouse gases and aerosols, is much less robust. Differences in how forcing factors are applied, in their radiative influence and in models' climate sensitivities, substantially influence the response patterns. We find that standard optimal detection methodologies cannot fully reconcile this response diversity. By selecting a set of experiments to enable the diagnosing of greenhouse gases and the combined influence of other anthropogenic and natural factors, we find robust detections of well‐mixed greenhouse gases across a large ensemble of models. Of the observed warming over the twentieth century of 0.65 K/century we find, using a multimodel mean not incorporating pattern uncertainty, a well‐mixed greenhouse gas warming of 0.87 to 1.22 K/century. This is partially offset by cooling from other anthropogenic and natural influences of −0.54 to −0.22 K/century. Although better constrained than recent studies, the attributable trends across climate models are still wide, with implications for observational constrained estimates of transient climate response. Some of the uncertainties could be reduced in future by having more model data to better quantify the simulated estimates of the signals and natural variability, by designing model experiments more effectively and better quantification of the climate model radiative influences. Most importantly, how model pattern uncertainties are incorporated into the optimal detection methodology should be improved.
Changes in precipitating snow chemistry with location and elevation in the California Sierra Nevada
Authors: Creamean Jessie M. , Axson Jessica L. , Bondy Amy L. , Craig Rebecca L. , May Nathaniel W. , Shen Hongru , Weber Michael H. , Pratt Kerri A. , Ault Andrew P. 
Published: June 2016

AbstractOrographic snowfall in the Sierra Nevada Mountains is an important source of water for California and can vary significantly on an annual basis. The microphysical properties of orographic clouds and subsequent formation of precipitation are impacted, in part, by aerosols of varying size, number, and chemical composition, which are incorporated into clouds formed along the Sierra barrier. Herein, the physicochemical properties and sources of insoluble residues and soluble ions found in precipitation samples were explored for three sites of variable elevation in the Sierra Nevada during the 2012–2013 winter season. Residues were characterized using a suite of physicochemical techniques to determine the size‐resolved number concentrations and associated chemical composition. A transition in the aerosol sources that served as cloud seeds or were scavenged in‐cloud and below‐cloud was observed as a function of location and elevation. Anthropogenic influence from the Central Valley was dominant at the two lowest elevation sites (1900 and 2200 m above mean sea level (AMSL)), whereas long‐range transported mineral dust was a larger contributor at the highest elevation site where cleaner conditions were observed (2600 m AMSL). The residues and soluble ions observed provide insight into how multiple aerosol sources can impact cloud and precipitation formation processes, even over relatively small spatial scales. The transition with increasing elevation to aerosols that serve as ice nucleating particles may impact the properties and extent of snowfall in remote mountain regions where snowpack provides a vital supply of water.
Validating a mass balance accounting approach to using 7Be measurements to estimate event‐based erosion rates over an extended period at the catchment scale
Authors: Porto Paolo , Walling Des E. , Cogliandro Vanessa , Callegari Giovanni 
Published: June 2016

AbstractUse of the fallout radionuclides cesium‐137 and excess lead‐210 offers important advantages over traditional methods of quantifying erosion and soil redistribution rates. However, both radionuclides provide information on longer‐term (i.e., 50–100 years) average rates of soil redistribution. Beryllium‐7, with its half‐life of 53 days, can provide a basis for documenting short‐term soil redistribution and it has been successfully employed in several studies. However, the approach commonly used introduces several important constraints related to the timing and duration of the study period. A new approach proposed by the authors that overcomes these constraints has been successfully validated using an erosion plot experiment undertaken in southern Italy. Here, a further validation exercise undertaken in a small (1.38 ha) catchment is reported. The catchment was instrumented to measure event sediment yields and beryllium‐7 measurements were employed to document the net soil loss for a series of 13 events that occurred between November 2013 and June 2015. In the absence of significant sediment storage within the catchment's ephemeral channel system and of a significant contribution from channel erosion to the measured sediment yield, the estimates of net soil loss for the individual events could be directly compared with the measured sediment yields to validate the former. The close agreement of the two sets of values is seen as successfully validating the use of beryllium‐7 measurements and the new approach to obtain estimates of net soil loss for a sequence of individual events occurring over an extended period at the scale of a small catchment.
Revisiting extreme storms of the past 100 years for future safety of large water management infrastructures
Authors: Chen Xiaodong , Hossain Faisal 
Published: June 2016

AbstractHistorical extreme storm events are widely used to make Probable Maximum Precipitation (PMP) estimates, which form the cornerstone of large water management infrastructure safety. Past studies suggest that extreme precipitation processes can be sensitive to land surface feedback and the planetary warming trend, which makes the future safety of large infrastructures questionable given the projected changes in land cover and temperature in the coming decades. In this study, a numerical modeling framework was employed to reconstruct 10 extreme storms over CONUS that occurred during the past 100 years, which are used by the engineering profession for PMP estimation for large infrastructures such as dams. Results show that the correlation in daily rainfall for such reconstruction can range between 0.4 and 0.7, while the correlation for maximum 3‐day accumulation (a standard period used in infrastructure design) is always above 0.5 for post‐1948 storms. This suggests that current numerical modeling and reanalysis data allow us to reconstruct big storms after 1948 with acceptable accuracy. For storms prior to 1948, however, reconstruction of storms shows inconsistency with observations. Our study indicates that numerical modeling and data may not have advanced to a sufficient level to understand how such old storms (pre‐1948) may behave in future warming and land cover conditions. However, the infrastructure community can certainly rely on the use of model reconstructed extreme storms of the 1948‐present period to reassess safety of our large water infrastructures under assumed changes in temperature and land cover.
S−to−P heterogeneity ratio in the lower mantle and thermo‐chemical implications
Authors: Tesoniero Andrea , Cammarano Fabio , Boschi Lapo 
Published: June 2016

AbstractWe evaluate the thermo‐chemical state of the lower mantle by analysing the differences in the pattern of heterogeneity between shear and compressional velocity variations and the
heterogeneity ratio (
) as mapped in our model SPani and in alternative joint models. Robust structural differences between VP and VS evidence the presence of compositional heterogeneity within the two Large Low Shear Velocity Provinces (LLSVPs). We find also an increasing decorrelation with depth that can be associated with compositional layering of the LLSVPs. In addition, our model shows heterogeneity in the transition zone and mid mantle by complex morphology of subducting slabs and further differences between VP and VS that point to an unexpected heterogeneous lower mantle. Precise estimates of compositional heterogeneities are not yet affordable because of the difficulty to provide quantitative measure of
, making it difficult to use this ratio to evaluate chemical heterogeneity. For instance,
global median value (
) drops from
to
, at 2500 km depth when the VP component of SPani is replaced by a VP model resulting from a differently regularized inversion and obtaining an equally good data fit. An increase of 20% of the SPani VP anomalies also drastically reduces
without significantly degrading the data fit. Noise in model parameters also leads to overestimate
in the two LLSVPs as we show with synthetic tests. Additional mineral physics uncertainties for compositional effects on
and for the conversion of
and
into density further complicates a precise chemical interpretation.
Meteoritic influence on sodium and potassium abundance in the lunar exosphere measured by LADEE
Authors: Szalay Jamey R. , Horányi Mihály , Colaprete Anthony , Sarantos Menelaos 
Published: June 2016

AbstractThe Lunar Atmosphere and Dust Environment Explorer (LADEE) orbited the Moon for approximately 6 months, taking data with the Lunar Dust Experiment (LDEX), Ultraviolet‐Visible Spectrometer (UVS), and Neutral Mass Spectrometer (NMS). Here we compare coincident LDEX measurements of meteoritic influx to exospheric column densities of Na and K derived by UVS. We report a strong correlation of exospheric potassium and meteoroid ejecta during the Geminids meteoroid shower, exhibiting a much stronger response than sodium. With the exception of the Geminids, we find a weak correlation between the sporadic meteoroid influx as measured by LDEX and exospheric density as measured by UVS.
Modeling 3‐D crustal velocities in the United States and Canada
Authors: Snay Richard A. , Freymueller Jeffrey T. , Craymer Michael R. , Pearson Chris F. , Saleh Jarir 
Published: June 2016

AbstractA numerical model for three‐dimensional (3‐D) crustal velocities has been derived for most of the United States and Canada, primarily from repeated geodetic data. This model provides a foundation for a prototype of the TRANS4D software. TRANS4D is being developed to enable geospatial professionals and others to transform 3‐D positional coordinates across time. The derived model reveals several macroscopic features of the 3‐D velocity field, including the pervasive presence of the glacial isostatic adjustment associated with the past melting of the ice fields that formed more than 19,000 years ago during the Last Glacial Maximum. In this study, the present‐day 3‐D velocity field associated with this melting (as estimated via the recently published ICE‐6G_C (VM5a) model) was subtracted from this study's total 3‐D velocity field to identify features of the residual velocity field. In particular, this study introduces the NA_ICE‐6G reference frame in which residual horizontal velocities have magnitudes that are less than 2 mm/yr everywhere east of longitude 104°W and south of latitude 60°N, except in southern Texas. Residual horizontal velocities of greater magnitude are found west and/or north of these two boundaries, and they are due mostly to interactions among tectonic plates with localized pockets due to other geophysical phenomena. Large residual vertical velocities, some with values exceeding 30 mm/yr, are found in southeastern Alaska. The uplift occurring here is due to present‐day melting of glaciers and ice fields formed during the Little Ice Age glacial advance that occurred between 1550 A.D. and 1850 A.D.
Interannual variability of winter‐spring temperature in the Middle Atlantic Bight: Relative contributions of atmospheric and oceanic processes
Authors: Chen Ke , Kwon Young‐Oh , Gawarkiewicz Glen 
Published: June 2016

AbstractRelative contributions between the local atmospheric and oceanic processes on the interannual variability of winter‐spring shelf temperature in the Middle Atlantic Bight (MAB) are investigated based on a regional ocean model. The model demonstrates sufficient capability to realistically simulate the interannual temperature changes during 2003–2014. On interannual time scales, the mean winter/spring temperature in the MAB is determined by the combination of the initial temperature at the beginning of the season and the mean cumulative air‐sea flux, while the mean cumulative ocean advective flux plays a secondary role. In spite of the overall importance of air‐sea flux in determining the winter and spring temperature, the relative contributions between air‐sea flux and ocean advective flux on the evolution of the temperature anomaly in each individual year varies. The predictability of spring (April–June) temperature based on winter (January–March) temperature is weak because the temporal decorrelation time scale changes significantly from year to year. Both the highly variable shelf temperature and its decorrelation time scale are affected by the changes in the relative contributions between the air‐sea flux and ocean advective flux.
Impact of current speed on mass flux to a model flexible seagrass blade
Authors: Lei Jiarui , Nepf Heidi 
Published: June 2016

AbstractSeagrass and other freshwater macrophytes can acquire nutrients from surrounding water through their blades. This flux may depend on the current speed (U), which can influence both the posture of flexible blades (reconfiguration) and the thickness of the flux‐limiting diffusive layer. The impact of current speed (U) on mass flux to flexible blades of model seagrass was studied through a combination of laboratory flume experiments, numerical modeling and theory. Model seagrass blades were constructed from low‐density polyethylene (LDPE), and 1, 2‐dichlorobenzene was used as a tracer chemical. The tracer mass accumulation in the blades was measured at different unidirectional current speeds. A numerical model was used to estimate the transfer velocity (K) by fitting the measured mass uptake to a one‐dimensional diffusion model. The measured transfer velocity was compared to predictions based on laminar and turbulent boundary layers developing over a flat plate parallel to flow, for whichand, respectively. The degree of blade reconfiguration depended on the dimensionless Cauchy number,Ca, which is a function of both the blade stiffness and flow velocity. For largeCa, the majority of the blade was parallel to the flow, and the measured transfer velocity agreed with laminar boundary layer theory,. For smallCa, the model blades remained upright, and the flux to the blade was diminished relative to the flat‐plate model. A meadow‐scale analysis suggests that the mass exchange at the blade scale may control the uptake at the meadow scale.
Basal melt, seasonal water mass transformation, ocean current variability, and deep convection processes along the Amery Ice Shelf calving front, East Antarctica
Authors: Herraiz‐Borreguero L. , Church J. A. , Allison I. , Peña‐Molino B. , Coleman R. , Tomczak M. , Craven M. 
Published: June 2016

AbstractDespite the Amery Ice Shelf (AIS) being the third largest ice shelf in Antarctica, the seasonal variability of the physical processes involved in the AIS‐ocean interaction remains undocumented and a robust observational, oceanographic‐based basal melt rate estimate has been lacking. Here we use year‐long time series of water column temperature, salinity, and horizontal velocities measured along the ice shelf front from 2001 to 2002. Our results show strong zonal variations in the distribution of water masses along the ice shelf front: modified Circumpolar Deep Water (mCDW) arrives in the east, while in the west, Ice Shelf Water (ISW) and Dense Shelf Water (DSW) formed in the Mackenzie polynya dominate the water column. Baroclinic eddies, formed during winter deep convection (down to 1100 m), drive the inflow of DSW into the ice shelf cavity. Our net basal melt rate estimate is 57.4 ± 25.3 Gt yr−1 (1 ± 0.4 m yr−1), larger than previous modeling‐based and glaciological‐based estimates, and results from the inflow of DSW (0.52 ± 0.38 Sv; 1 Sv = 106 m3 s−1) and mCDW (0.22 ± 0.06 Sv) into the cavity. Our results highlight the role of the Mackenzie polynya in the seasonal exchange of water masses across the ice shelf front, and the role of the ISW in controlling the formation rate and thermohaline properties of DSW. These two processes directly impact on the ice shelf mass balance, and on the contribution of DSW/ISW to the formation of Antarctic Bottom Water.
Influence of the Processing Parameters on the Dispersion and Coloration Behavior of a Halogenated Copper Phthalocyanine‐Based Masterbatch
Authors: Buccella Mauro , Dorigato Andrea , Rizzola Fabio , Caldara Mauro , Fambri Luca 
Published: June 2016

AbstractA monodispersed green masterbatch was produced through an industrial extrusion process, by mixing a commercial Polyamide 6 matrix (PA6) with a halogenated copper phthalocyanine green pigment. The production process was investigated and optimized in order to improve the pigment dispersion, reducing the clogging power and increasing the color strength of the resulting products. The compounding process based on three extrusions without filtration led to a filter pressure value (FPV) reduction of about 84% and a relative color strength (RCS) increase of about 50% with respect to the standard production process (i.e single extrusion). The thermal stability of the prepared compounds was evaluated by rheological test, viscosity measurements, and end group analysis, and it was found that a triple extrusion without filtration promoted thermo‐oxidative matrix degradation. However, the same processing conditions led to a significant reduction of the production waste, increasing the productivity and the quality of the final product.
Magnetically Guided Protein Transduction by Hybrid Nanogel Chaperones with Iron Oxide Nanoparticles
Authors: Kawasaki Riku , Sasaki Yoshihiro , Katagiri Kiyofumi , Mukai Sada‐atsu , Sawada Shin‐ichi , Akiyoshi Kazunari 
Published: June 2016

AbstractProtein pharmaceuticals show great therapeutic promise, but effective intracellular delivery remains challenging. To address the need for efficient protein transduction systems, we used a magnetic nanogel chaperone (MC): a hybrid of a polysaccharide nanogel, a protein carrier with molecular chaperone‐like properties, and iron oxide nanoparticles, enabling magnetically guided delivery. The MC complexed with model proteins, such as BSA and insulin, and was not cytotoxic. Cargo proteins were delivered to the target HeLa cell cytosol using a magnetic field to promote movement of the protein complex toward the cells. Delivery was confirmed by fluorescence microscopy and flow cytometry. Delivered β‐galactosidase, inactive within the MC complex, became enzymatically active within cells to convert a prodrug. Thus, cargo proteins were released from MC complexes through exchange interactions with cytosolic proteins. The MC is a promising tool for realizing the therapeutic potential of proteins.
Mechanistische Charakterisierung von zwei Sesquiterpen‐Cyclasen aus dem phytopathogenen Pilz Fusarium fujikuroi
Authors: Burkhardt Immo , Siemon Thomas , Henrot Matthias , Studt Lena , Rösler Sarah , Tudzynski Bettina , Christmann Mathias , Dickschat Jeroen S. 
Published: June 2016

AbstractZwei Sesquiterpencyclasen aus Fusarium fujikuroi wurden in Escherichia coli exprimiert und gereinigt. Das erste Enzym war wegen einer kritischen Mutation inaktiv, die Aktivität konnte aber durch Sequenzkorrektur per ortsgerichteter Mutagenese wiederhergestellt werden. Das mutierte Enzym und zwei natürlicherweise funktionale Homologe aus anderen Fusarien konvertierten Farnesyldiphosphat zu Guaia‐6,10(14)‐dien. Das zweite Enzym produzierte Eremophilen. Die absolute Konfiguration von Guaia‐6,10(14)‐dien wurde durch enantioselektive Synthese aufgeklärt, während die des Eremophilens aus dem Vorzeichen der optischen Drehung ableitbar war und derjenigen aus Pflanzen entgegengesetzt ist, aber mit der aus Sorangium cellulosum übereinstimmt. Die Mechanismen beider Terpencyclasen wurden mithilfe diverser 13C‐ und 2H‐markierter FPP‐Isotopomere studiert.
Nitrogen‐Doped Ordered Mesoporous Carbon Supported Bimetallic PtCo Nanoparticles for Upgrading of Biophenolics
Authors: Wang Guang‐Hui , Cao Zhengwen , Gu Dong , Pfänder Norbert , Swertz Ann‐Christin , Spliethoff Bernd , Bongard Hans‐Josef , Weidenthaler Claudia , Schmidt Wolfgang , Rinaldi Roberto , Schüth Ferdi 
Published: June 2016

AbstractHydrodeoxygenation (HDO) is an attractive route for the upgrading of bio‐oils produced from lignocellulose. Current catalysts require harsh conditions to effect HDO, decreasing the process efficiency in terms of energy and carbon balance. Herein we report a novel and facile method for synthesizing bimetallic PtCo nanoparticle catalysts (ca. 1.5 nm) highly dispersed in the framework of nitrogen‐doped ordered mesoporous carbon (NOMC) for this reaction. We demonstrate that NOMC with either 2D hexagonal (p6m) or 3D cubic (Im
m) structure can be easily synthesized by simply adjusting the polymerization temperature. We also demonstrate that PtCo/NOMC (metal loading: Pt 9.90 wt %; Co 3.31 wt %) is a highly effective catalyst for HDO of phenolic compounds and “real‐world” biomass‐derived phenolic streams. In the presence of PtCo/NOMC, full deoxygenation of phenolic compounds and a biomass‐derived phenolic stream is achieved under conditions of low severity.
Hollow Carbon Nanobubbles: Synthesis, Chemical Functionalization, and Container‐Type Behavior in Water
Authors: Hofer Corinne J. , Grass Robert N. , Zeltner Martin , Mora Carlos A. , Krumeich Frank , Stark Wendelin J. 
Published: June 2016

AbstractThin‐walled, hollow carbon nanospheres with a hydrophobic interior and good water dispersability can be synthesized in two steps: First, metal nanoparticles, coated with a few layers of graphene‐like carbon, are selectively modified on the outside with a covalently attached hydrophilic polymer. Second, the metal core is removed at elevated temperature treatment with acid, leaving a well‐defined carbon‐based hydrophobic cavity. Loading experiments with the dye rhodamine B and doxorubicin confirmed the filling and release of a cargo and adjustment of a dynamic equilibrium (cargo‐loaded versus release). Rhodamine B preferably accumulates in the interior of the bubbles. Filled nanobubbles allowed constant dye release into pure water. Studies of the concentration‐dependent loading and release show an unusual hysteresis.
GM1 Ganglioside Inhibits β‐Amyloid Oligomerization Induced by Sphingomyelin
Authors: Amaro Mariana , Šachl Radek , Aydogan Gokcan , Mikhalyov Ilya I. , Vácha Robert , Hof Martin 
Published: June 2016

Abstractβ‐Amyloid (Aβ) oligomers are neurotoxic and implicated in Alzheimer's disease. Neuronal plasma membranes may mediate formation of Aβ oligomers in vivo. Membrane components sphingomyelin and GM1 have been shown to promote aggregation of Aβ; however, these studies were performed under extreme, non‐physiological conditions. We demonstrate that physiological levels of GM1, organized in nanodomains do not seed oligomerization of Aβ40 monomers. We show that sphingomyelin triggers oligomerization of Aβ40 and that GM1 is counteractive thus preventing oligomerization. We propose a molecular explanation that is supported by all‐atom molecular dynamics simulations. The preventive role of GM1 in the oligomerization of Aβ40 suggests that decreasing levels of GM1 in the brain, for example, due to aging, could reduce protection against Aβ oligomerization and contribute to the onset of Alzheimer's disease.