bluuebunny/crossref_metadata_2025_split huggingface dataset:
Radio frequency ice dielectric permittivity measurements using CReSIS data
Authors: Stockham M. , Macy J. , Besson D. 
Published: February 2016

AbstractWe report on studies of the ice dielectric permittivity using 150–195 MHz radar depth sounding data accumulated by the Center for Remote Sensing of Ice Sheets group, based at the University of Kansas. In the context of astroparticle physics experiments aimed at understanding radio emissions from cosmic rays interacting in the Earth's polar regions, our goals for this study were twofold: (1) identify radio frequency wave speed polarization asymmetries in Antarctica and (for the first time) in Greenland and (2) directly extract the depth dependence of the radio frequency field attenuation length as well as map out the attenuation over a large area. We first examine asymmetries in the real part of the permittivity (index‐of‐refraction
) using Center for Remote Sensing of Ice Sheets bedrock radar reflection data taken from a single location, but with different signal polarizations. These data indicate birefringence for flow parallel‐, versus perpendicular‐to the local ice‐flow direction, with the former corresponding to smaller index‐of‐refraction (i.e., faster wave speed). Second, we have investigated the imaginary part of the permittivity (
) and extracted the depth dependence of the field attenuation length (
), as well as estimated the depth‐averaged radio frequency attenuation length from data taken near the Greenland Ice Core Project site near Summit, Greenland. We obtain
m based on calculated values in the 1000–2000 m ice depth interval to which we have sensitivity and extrapolated to the full depth, where the errors shown reflect our uncertainty in our extrapolation. We also observe the expected decrease in attenuation length with increasing depth/temperature. A depth‐averaged attenuation length is also extracted directly from the relative strengths of the observed bedrock versus surface returns over large regions of both Greenland and Antarctica.
Characterization of interfade duration for satellite communication systems design and optimization in a temperate climate
Authors: Jorge Flávio , Riva Carlo , Rocha Armando 
Published: February 2016

AbstractThe characterization of the fade dynamics on Earth‐satellite links is an important subject when designing the so called fade mitigation techniques that contribute to the proper reliability of the satellite communication systems and the customers' quality of service (QoS). The interfade duration, defined as the period between two consecutive fade events, has been only poorly analyzed using limited data sets, but its complete characterization would enable the design and optimization of the satellite communication systems by estimating the system requirements to recover in time before the next propagation impairment. Depending on this analysis, several actions can be taken ensuring the service maintenance. In this paper we present for the first time a detailed and comprehensive analysis of the interfade events statistical properties based on 9 years of in‐excess attenuation measurements at Ka band (19.7 GHz) with very high availability that is required to build a reliable data set mainly for the longer interfade duration events. The number of years necessary to reach the statistical stability of interfade duration is also evaluated for the first time, providing a reference when accessing the relevance of the results published in the past. The study is carried out in Aveiro, Portugal, which is conditioned by temperate Mediterranean climate with Oceanic influences.
Residence times of stream‐groundwater exchanges due to transient stream stage fluctuations
Authors: McCallum James L. , Shanafield Margaret 
Published: February 2016

AbstractThe biogeochemical functioning of stream ecosystems is heavily dependent on water and water‐borne nutrient fluxes between the stream itself and the streambed and banks (i.e., the hyporheic zone). The travel time of water exchanges through the hyporheic zone has been investigated previously; however, these studies have primarily modeled exchanges under steady state conditions assuming spatial pressure variations. This assumes that the hydraulic gradients that drive the exchanges are maintained the whole time the stream water remains in the bed or banks, which is unrealistic. Therefore, in this study we use a transient approach to investigate residence time distributions (RTDs) of bank inflow and bank outflow during both regular, diurnal stream stage variations and storm flow events. We demonstrate that RTDs reflect the timing and magnitude bank inflows, rather than smooth RTDs. We also show that small percentages of water from a given bank inflow event may be present in bank outflows for long periods of time, due to dispersion and diffusion within the bank, and lower rates of bank outflow, relative to bank inflow. This is apparent in the synthetic model of a single storm flow event, where 10% remained in the bank after 50 days. Additionally, residence times for a given bank inflow event are longer when repeated events occur, because the bank outflows from one event are “interrupted” by an increase in stream stage during a successive event. For example, field data capturing events of variable timing and magnitude showed that 70 days after each of three storm flow events occurred, 40, 12 and 30% of the bank inflow event remained in the banks. These cases indicate that bank exchanges are temporally dynamic and the RTDs of return flows can have significant tailing, which will dictate rates of nutrient exchange within the near‐stream environment.
Crustal imaging across the North Anatolian Fault Zone from the autocorrelation of ambient seismic noise
Authors: Taylor George , Rost Sebastian , Houseman Gregory 
Published: February 2016

AbstractSeismic images of active fault zones can be used to examine the structure of faults throughout the crust and upper mantle and give clues as to whether the associated deformation occurs within a narrow shear zone or is broadly distributed through the lower crust. Limitations on seismic resolution within the crust and difficulties imaging shallow structures such as the crust‐mantle boundary (Moho) place constraints on the interpretation of seismic images. In this study we retrieve body wave reflections from autocorrelations of ambient seismic noise. The instantaneous phase coherence autocorrelations allow unprecedented ambient noise images of the North Anatolian Fault Zone (NAFZ). Our reflection profiles show a Moho reflected P wave and additional structure within the crust and upper mantle. We image a distinct vertical offset of the Moho associated with the northern branch of the NAFZ indicating that deformation related to the fault remains narrow in the upper mantle.
Episodic ice velocity fluctuations triggered by a subglacial flood in West Antarctica
Authors: Siegfried Matthew R. , Fricker Helen A. , Carter Sasha P. , Tulaczyk Slawek 
Published: February 2016

AbstractHeight change anomalies in satellite altimeter data have been interpreted as the surface expressions of basal water moving into and out of subglacial lakes. These signals have been mapped throughout Antarctica on timescales of months to years, but only broad connections have been made between active lakes and ice dynamics. We present the first high‐frequency observations of ice velocity evolution due to a cascading subglacial lake drainage event, collected over 5 years (2010–2015) using Global Positioning System data on Whillans and Mercer ice streams, West Antarctica. We observed three episodic ice velocity changes over 2 years, where flow speed increased by up to 4%, as well as an 11 month disruption of the tidally modulated stick‐slip cycle that dominates regional ice motion. Our observations reveal that basal conditions of an Antarctic ice stream can rapidly evolve and drive a dynamic ice response on subannual timescales, which can bias observations used to infer long‐term ice sheet changes.
A new approach for assessing the future of aquifers supporting irrigated agriculture
Authors: Butler James J. , Whittemore Donald O. , Wilson Blake B. , Bohling Geoffrey C. 
Published: February 2016

AbstractAquifers supporting irrigated agriculture are under stress worldwide as a result of large pumping‐induced water deficits. To aid in the formulation of more sustainable management plans for such systems, we have developed a water balance approach for assessing the impact of proposed management actions and the prospects for aquifer sustainability. Application to the High Plains aquifer (HPA) in the state of Kansas in the United States reveals that practically achievable reductions in annual pumping (<22%) would have stabilized areally averaged water levels over much of the Kansas HPA from 1996 to 2013. This demonstrates that modest pumping reductions can have a significant impact and highlights the importance of reliable pumping data for determining the net inflow (capture) component of the water balance. The HPA is similar to many aquifers supporting critically needed agricultural production, so the presented approach should prove of value far beyond the area of this initial application.
Transport of ice into the stratosphere and the humidification of the stratosphere over the 21st century
Authors: Dessler A.E. , Ye H. , Wang T. , Schoeberl M.R. , Oman L.D. , Douglass A.R. , Butler A.H. , Rosenlof K.H. , Davis S.M. , Portmann R.W. 
Published: February 2016

AbstractClimate models predict that tropical lower stratospheric humidity will increase as the climate warms. We examine this trend in two state‐of‐the‐art chemistry‐climate models. Under high greenhouse gas emissions scenarios, the stratospheric entry value of water vapor increases by ~1 ppmv over the 21st century in both models. We show with trajectory runs driven by model meteorological fields that the warming tropical tropopause layer (TTL) explains 50–80% of this increase. The remainder is a consequence of trends in evaporation of ice convectively lofted into the TTL and lower stratosphere. Our results further show that within the models we examined, ice lofting is primarily important on long time scales; on interannual time scales, TTL temperature variations explain most of the variations in lower stratospheric humidity. Assessing the ability of models to realistically represent ice lofting processes should be a high priority in the modeling community.
Earlier green‐up and spring warming amplification over Europe
Authors: Ma Shaoxiu , Pitman Andy J. , Lorenz Ruth , Kala Jatin , Srbinovsky Jhan 
Published: February 2016

AbstractThe onset of green‐up of plants has advanced in response to climate change. This advance has the potential to affect heat waves via biogeochemical and biophysical processes. Here a climate model was used to investigate only the biophysical feedbacks of earlier green‐up on climate as the biogeochemical feedbacks have been well addressed. Earlier green‐up by 5 to 30 days amplifies spring warming in Europe, especially heat waves, but makes few differences to heat waves in summer. This spring warming is most noticeable within 30 days of advanced green‐up and is associated with a decrease in low‐ and middle‐layer clouds and associated increases of downward short wave and net radiation. We find negligible differences in the Southern Hemisphere and low latitudes of the Northern Hemisphere. Our results provide an estimate of the level of skill necessary in phenology models to avoid introducing biases in climate simulations.
Dominant flood generating mechanisms across the United States
Authors: Berghuijs Wouter R. , Woods Ross A. , Hutton Christopher J. , Sivapalan M. 
Published: February 2016

AbstractRiver flooding can have severe societal, economic, and environmental consequences. However, limited understanding of the regional differences in flood‐generating mechanisms results in poorly understood historical flood trends and uncertain predictions of future flood conditions. Through systematic data analyses of 420 catchments we expose the primary drivers of flooding across the contiguous United States. This is achieved by exploring which flood‐generating processes control the seasonality and magnitude of maximum annual flows. The regional patterns of seasonality and interannual variabilities of maximum annual flows are, in general, poorly explained by rainfall characteristics alone. For most catchments soil moisture dependent precipitation excess, snowmelt, and rain‐on‐snow events are found to be much better predictors of the flooding responses. The continental‐scale classification of dominant flood‐generating processes we generate here emphasizes the disparity in timing and variability between extreme rainfall and flooding and can assist predictions of flooding and flood risk within the continental U.S.
Observed and projected decrease in Northern Hemisphere extratropical cyclone activity in summer and its impacts on maximum temperature
Authors: Chang Edmund K. M. , Ma Chen‐Geng , Zheng Cheng , Yau Albert M. W. 
Published: February 2016

AbstractExtratropical cyclones cause much of the high‐impact weather over the midlatitudes. With increasing greenhouse gases, enhanced high‐latitude warming will lead to weaker cyclone activity. Here we show that between 1979 and 2014, the number of strong cyclones in Northern Hemisphere in summer has decreased at a rate of 4% per decade, with even larger decrease found near northeastern North America. Climate models project a decrease in summer cyclone activity, but the observed decreasing rate is near the fastest projected. Decrease in summer cyclone activity will lead to decrease in cloud cover, giving rise to higher maximum temperature, potentially enhancing the increase in maximum temperature by 0.5 K or more over some regions. We also show that climate models may have biases in simulating the positive relationship between cyclone activity and cloud cover, potentially underestimating the impacts of cyclone decrease on accentuating the future increase in maximum temperature.
A new framework for monitoring flood inundation using readily available satellite data
Authors: Parinussa Robert M. , Lakshmi Venkat , Johnson Fiona M. , Sharma Ashish 
Published: February 2016

AbstractFloods are deadly natural disasters that have large social and economic impact. Their impact can be reduced through near real‐time warning systems utilizing information from satellite remote sensing for flood tracking and forecasting. In this study we formulate that differences in day and night land surface temperature (ΔLST) are a skillful predictor for inundation and can serve parallel to soil moisture in warning systems. Satellite measurements of ΔLST and soil moisture revealed distinct spatial patterns for the extreme hydrological conditions that Australia has encountered since 2002. A significant flood revealed large negative ΔLST anomalies whereas droughts corresponded to positive anomalies. ΔLST and soil moisture showed distinct behavior prior to flooding as anomalies displayed gradual build up, suggesting signals could be valuable in flood warning systems. Strong agreement was found between ΔLST, antecedent precipitation index, and soil moisture anomalies over Australia and the Murray Darling Basin. This indicates their skills to represent wetness state, an important input additional to precipitation in flood warning systems.
Adichie, Chimamanda Ngozi
Authors: Iyer Nalini 
Published: February 2016

Abstract

Chimamanda Ngozi Adichie (b. 1977) is the author of three novels, a collection of short stories, a play, a collection of poems, and numerous uncollected short stories, essays, and poems. Her work has appeared in prestigious publications, including
The New Yorker
,
Zoetrope
,
Ms
., and
Calyx
. Born in Nigeria, Adichie moved to the United States for her education at the age of 19. She is recognized as a major twenty‐first‐century African voice and some critics see her as the literary descendant of Chinua Achebe.
Arabic Literature
Authors: Salama Mohammad 
Published: February 2016

AbstractDespite vigorous multiplicity of naming and renaming the corpse of Arabic literature produced during and after the age of decolonization, basic questions like “What is post‐colonial Arabic literature?” or “What does the post‐colonial in Arabic literature stand for?” are seldom posed. It appears the question remains tangential for most literary scholarship, which tends to focus either on individual authors or, dialectically, on panoramic expositions of various themes, sub‐themes, or genres under a given rubric. As this entry shows, postcolonial Arabic literature follows a crooked line that at times tends to continue smoothly, while at others appears to swerve brusquely from, an earlier self‐assured national vision of the Arab world ‐ one that emerged in the first half of the twentieth century as anti‐colonial resistance literature. This position complicates doctrinal nomenclatural appropriations of modern Arabic literature and raises important questions about causality and continuity, especially as it pertains to an expanded and more complex context accentuating the spread of ideas and dialogue among multiple actors.
Roumain, Jacques
Authors: Kaussen Valerie 
Published: February 2016

Abstract

Jacques Roumain was a Haitian writer who continues to be best known for his 1944 novel
Gouverneurs de la rosée
(
Masters of the Dew
). Roumain also composed short fiction, poetry, works of ethnology, and several essays on the politics of race, colonialism, and social class. A classic of world literature,
Gouverneurs de la rosée
is also an example of the engaged international modernism of Caribbean intellectuals writing during the period of decolonization.
Utopia
Authors: Bahrawi Nazry 
Published: February 2016

AbstractUtopia is a complex theoretical and material concept that runs the risk of oversimplification in today's world. This entry explores the idea of utopia from the postcolonial perspective. It outlines the ways in which utopianism can be seen as a ubiquitous impulse that exist in Western and non‐Western, civilizations, its revolutionary element as well as its link to the literary genres of travel writing, science fiction and the bildungsroman.
Chiral Brønsted Acid Catalyzed Kinetic Resolutions
Authors: Petersen Kimberly S. 
Published: February 2016

AbstractThe synthesis of enantioenriched small molecules is an ongoing goal of organic chemists. This Focus Review explores the use of kinetic resolutions catalyzed by chiral Brønsted acids. Methods include classic kinetic resolutions and dynamic kinetic resolutions. The small molecules obtained are potentially valuable intermediates in the synthesis of biologically important compounds.
Synthesis and Functionalization of 5,7‐Dinitroquinoline and Its N‐Oxide
Authors: Starosotnikov Alexey M. , Nikol'skiy Vladislav V. , Borodulya Anastasiya N. , Kachala Vadim V. , Bastrakov Maxim A. , Solkan Vitaly N. , Shevelev Svyatoslav A. 
Published: February 2016

AbstractAn efficient method was developed for the synthesis of 5,7‐dinitroquinoline and its N‐oxide. The reactions of these compounds with either thiols or sodium azide resulted in the regiospecific substitution of 5‐NO2 group and the formation of previously unknown quinoline derivatives. The 5‐azido derivatives underwent reactions with 1,3‐dicarbonyl compounds and, depending on the nature of reagent, afforded either 5‐(1,2,3‐triazol)‐1‐yl‐ or 5‐amino‐7‐nitroquinolines, which have been previously inaccessible by using other methods.
Thermally exfoliated graphene oxide reinforced fluorinated pentablock poly(l‐lactide‐co‐ε‐caprolactone) electrospun scaffolds: Insight into antimicrobial activity and biodegradation
Authors: Okan Burcu Saner , Marset Azucena , Seyyed Monfared Zanjani Jamal , Sut Pınar Akkus , Sen Ozlem , Çulha Mustafa , Menceloglu Yusuf 
Published: February 2016

ABSTRACTThree‐dimensional fluorinated pentablock poly(l‐lactide‐co‐ε‐caprolactone)‐based scaffolds were successfully produced by the incorporation of thermally exfoliated graphene oxide (TEGO) as an antimicrobial agent with an electrospinning technique. In a ring‐opening polymerization, the fluorinated groups in the middle of polymer backbone were attached with a perfluorinated reactive stabilizer having oxygen‐carrying ability. The fiber diameter and its morphologies were optimized through changes in TEGO amount, voltage, polymer concentration, and solvent type to obtain an ideal scaffold structure. Instead of the widely used graphene oxide synthesized by Hummer's method, TEGO sheets having a low amount of oxygen produced by thermal expansion were integrated into the fiber structure to investigate the effect of the oxygen functional groups of TEGO sheets on the degradation and antimicrobial activity of the scaffolds. There was no antimicrobial activity in TEGO‐reinforced scaffolds in the in vitro tests in contrast to the literature. This study confirmed that a low number of oxygen functional groups on the surface of TEGO restricted the antimicrobial activity of the fabricated composite scaffolds. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43490.
Macrocyclic 2,7‐Anthrylene Oligomers
Authors: Yamamoto Yuta , Wakamatsu Kan , Iwanaga Tetsuo , Sato Hiroyasu , Toyota Shinji 
Published: February 2016

AbstractA macrocyclic compound consisting of six 2,7‐anthrylene units was successfully synthesized by Ni‐mediated coupling of the corresponding dibromo precursor as a novel π‐conjugated compound. This compound was sufficiently stable and soluble in organic solvents due to the presence of mesityl groups. X‐ray analysis showed that the molecule had a nonplanar and hexagonal wheel‐shaped framework of approximately S6 symmetry. The dynamic process between two S6 structures was observed by using the dynamic NMR technique, the barrier being 58 kJ mol−1. The spectroscopic properties of the hexamer were compared with those of analogous linear oligomers.
Development of a Multifunctional Benzophenone Linker for Peptide Stapling and Photoaffinity Labelling
Authors: Wu Yuteng , Olsen Lasse B. , Lau Yu Heng , Jensen Claus Hatt , Rossmann Maxim , Baker Ysobel R. , Sore Hannah F. , Collins Súil , Spring David R. 
Published: February 2016

AbstractPhotoaffinity labelling is a useful method for studying how proteins interact with ligands and biomolecules, and can help identify and characterise new targets for the development of new therapeutics. We present the design and synthesis of a novel multifunctional benzophenone linker that serves as both a photo‐crosslinking motif and a peptide stapling reagent. Using double‐click stapling, we attached the benzophenone to the peptide via the staple linker, rather than by modifying the peptide sequence with a photo‐crosslinking amino acid. When applied to a p53‐derived peptide, the resulting photoreactive stapled peptide was able to preferentially crosslink with MDM2 in the presence of competing protein. This multifunctional linker also features an extra alkyne handle for downstream applications such as pull‐down assays, and can be used to investigate the target selectivity of stapled peptides.
Predictors of mortality after mitraclip therapy
Authors: Cilingiroglu Mehmet , Marmagkiolis Konstantinos 
Published: February 2016

Key Points

Percutaneous mitral valve repair with Mitraclip remains to be the preferred therapy for those patients with congestive heart failure with severe mitral regurgitation who are deemed high‐surgical risk.
Failure of successful MR reduction, preprocedural NYHA functional class III‐IV, elevated ProBNP levels, presence of severe tricuspid regurgitation, pulmonary hypertension, right ventricular dysfunction and advanced age seems to be predictors of long term mortality.
Preprocedural patient characteristics needs to be carefully evaluated for optimal patient selection for Mitraclip therapy.