bluuebunny/crossref_metadata_2025_split huggingface dataset:
Atmospheric fronts in current and future climates
Authors: Catto J. L. , Nicholls N. , Jakob C. , Shelton K. L. 
Published: October 2014

AbstractAtmospheric fronts are important for the day‐to‐day variability of weather in the midlatitudes. It is therefore vital to know how their distribution and frequency will change in a projected warmer climate. Here we apply an objective front identification method, based on a thermal front parameter, to 6‐hourly data from models participating in Coupled Model Intercomparison Project phase 5. The historical simulations are evaluated against ERA‐Interim and found to produce a similar frequency of fronts and with similar front strength. The models show some biases in the location of the front frequency maxima. Future changes are estimated using the high emissions scenario simulations (Representative Concentration Pathway 8.5). Projections show an overall decrease in front frequency in the Northern Hemisphere, with a poleward shift of the maxima of front frequency and a strong decrease at high latitudes where the temperature gradient is decreased. The Southern Hemisphere shows a poleward shift of the frequency maximum, consistent with previous storm track studies.
Turbulence in the Earth's cusp region: The k‐filtering analysis
Authors: Wang Tieyan , Cao Jin‐Bin , Fu Huishan , Liu Wenlong , Dunlop Malcolm 
Published: October 2014

AbstractOn 13 April 2002, four Cluster spacecraft with separations up to 127 km measured similar turbulence in the exterior cusp during northward interplanetary magnetic field (IMF) Bz. Both the power spectra of magnetic and electric field fluctuations resemble the classical Kolmogorov power law, with the scaling f−1.7 under the proton gyrofrequency fcp (~0.3 Hz), breaks near fcp, and then steepens with the scalings f−2.8 and f−2.0 up to 10 Hz, respectively. The observed ratio of the electric to magnetic field is in agreement with the theoretical values of |δE/δB| for the quasi‐perpendicular kinetic Alfvén waves (KAWs), which reflects the features of Alfvén turbulence. The wave vector and dispersion relation of the turbulence are obtained using k‐filtering technique. The results show that the waves propagate quasi‐perpendicularly to the background magnetic field. The similarity between the experimental and the theoretical dispersion relations indicates that the measured waves are kinetic Alfvén wave. The waves have right‐handed elliptical polarization in the plane perpendicular to k. The main axis of polarization ellipse is perpendicular to the average magnetic field. These features furthermore indicate that the turbulence properties agree well with those of KAW mode. The observed KAW is much possibly produced through resonance mode conversion. We calculate the density gradient vector using multipoint density data and found that the waves propagate basically toward high‐density region. The density gradient in the exterior cusp provides a favorable condition for the resonance converted KAW.
Statistical results describing the bandwidth and coherence coefficient of whistler mode waves using THEMIS waveform data
Authors: Gao X. , Li W. , Thorne R. M. , Bortnik J. , Angelopoulos V. , Lu Q. , Tao X. , Wang S. 
Published: October 2014

AbstractThe bandwidths and coherence coefficients of lower band whistler mode waves are analyzed using Time History of Events and Macroscale Interactions during Substorms (THEMIS) waveform data for rising tones, falling tones, and hiss‐like emissions separately. We also evaluate their dependences on the spatial location, electron density, the ratio of plasma frequency to local electron gyrofrequency (fpe/fce), and the wave amplitude. Our results show that the bandwidth normalized by the local electron gyrofrequency (fce) of rising and falling tones is very narrow (~0.01 fce), smaller than that of the hiss‐like emissions (~0.025 fce). Meanwhile, the normalized bandwidth of discrete emissions gradually decreases with increasing wave amplitude, whereas that of hiss‐like emissions increases slowly. The coherence coefficient of rising and falling tones is extremely large (~1), while the coherence coefficient of hiss‐like emissions is smaller but is still larger than 0.5. For all categories of whistler mode waves, the normalized bandwidth increases at larger L shells. Furthermore, the normalized bandwidth is positively correlated with local fpe/fce but is inversely correlated with the electron density. Interactions between radiation belt electrons and whistler mode waves have been widely described by quasi‐linear diffusion theory. Our results suggest that although quasi‐linear theory is not entirely applicable for modeling electron interactions with rising and falling tones due to their narrow bandwidth and high coherence coefficient, it is suitable to treat wave‐particle interactions between electrons and low‐amplitude hiss‐like emissions. Moreover, the correlations between the normalized bandwidth of chorus waves (especially the discrete emissions) and other parameters may provide insights for the generation mechanism of chorus waves.
Characteristics of precipitating energetic electron fluxes relative to the plasmapause during geomagnetic storms
Authors: Whittaker Ian C. , Clilverd Mark A. , Rodger Craig J. 
Published: October 2014

AbstractIn this study we investigate the link between precipitating electrons from the Van Allen radiation belts and the dynamical plasmapause. We consider electron precipitation observations from the Polar Orbiting Environmental Satellite (POES) constellation during geomagnetic storms. Superposed epoch analysis is performed on precipitating electron observations for the 13 year period of 1999 to 2012 in two magnetic local time (MLT) sectors, morning and afternoon. We assume that the precipitation is due to wave‐particle interactions and our two MLT sectors focus on chorus (outside the plasmapause) and plasmaspheric hiss (inside the plasmapause) waves. We generate simple expressions based on the geomagnetic index, Dst, which reproduce the chorus‐driven observations for the >30 keV precipitating electron flux magnitudes. Additionally, we find expressions for the fitted spectral index to describe the flux variation with energy, allowing a full energy reproduction as a function of distance from the plasmapause. The hiss‐driven precipitating flux occurs inside the plasmapause but is independent of distance from the plasmapause. In the POES observations the hiss‐induced electron precipitation is only detectable above the instrument noise in the >300 keV and P6 (>800 keV) channels of the flux detection instrument. We have derived expressions for the storm time variation in flux inside the plasmapause using Dst as a proxy. The observations show that there is little evidence for >800 keV electron precipitation occurring outside of the plasmapause, in the MLT sectors studied.
Seasonal prediction of the South Pacific Convergence Zone in the austral wet season
Authors: Charles A. N. , Brown J. R. , Cottrill A. , Shelton K. L. , Nakaegawa T. , Kuleshov Y. 
Published: October 2014

AbstractThe position and orientation of the South Pacific Convergence Zone (SPCZ), modulated by the El Niño‐Southern Oscillation (ENSO), determine many of the potentially predictable interannual variations in rainfall in the South Pacific region. In this study, the predictability of the SPCZ in austral summer is assessed using two coupled (ocean‐atmosphere) global circulation model (CGCM)‐based seasonal prediction systems: the Japan Meteorological Agency's Meteorological Research Institute Coupled Ocean‐Atmosphere General Circulation Model (JMA/MRI‐CGCM) and the Australian Bureau of Meteorology's Predictive Ocean‐Atmosphere Model for Australia (POAMA‐M24). Forecasts of austral summer rainfall, initialized in November are assessed over the period 1980–2010. The climatology of CGCM precipitation in the SPCZ region compares favorably to rainfall analyses over subsets of years characterizing different phases of ENSO. While the CGCMs display biases in the mean SPCZ latitudes, they reproduce interannual variability in austral summer SPCZ position indices for forecasts out to 4 months, with temporal correlations greater than 0.6. The summer latitude of the western branch of the SPCZ is predictable with correlations of the order of 0.6 for forecasts initialized as early as September, while the correlation for the eastern branch only exceeds 0.6 for forecasts initialized in November. Encouragingly, the models are able to simulate the large displacement of the SPCZ during zonal SPCZ years 1982–1983, 1991–1992, and 1997–1998.
Impact of resolution on simulation of closed mesoscale cellular convection identified by dynamically guided watershed segmentation
Authors: Martini Matus N. , Gustafson William I. , Yang Qing , Xiao Heng 
Published: October 2014

AbstractOrganized mesoscale cellular convection (MCC) is a common feature of marine stratocumulus clouds that forms in response to interactions among dynamic, microphysical, and radiative processes at the mesoscale. Cloud resolving models begin to resolve some of these processes, but using high resolutions is extremely costly. To understand the impact of limited resolution on MCC, we use the Weather Research and Forecasting model with chemistry and fully coupled cloud‐aerosol interactions to simulate MCC over the southeast Pacific during the Variability of the American Monsoon Systems Ocean‐Cloud‐Atmosphere‐Land Study Regional Experiment (VOCALS‐REx). A suite of experiments with 3 and 9 km grid spacing indicates that the simulations with finer grid spacing have smaller liquid water paths and cloud fractions, while cloud tops are higher. The observed diurnal cycle is reasonably well simulated. To isolate organized MCC characteristics, we develop a new automated method that uses the watershed segmentation combining the detection of cloud boundaries with coincident vertical velocities. This ensures that the detected cloud fields are dynamically consistent for closed MCC, a common feature within the VOCALS‐REx region. We demonstrate that the 3 km simulation is able to reproduce the scaling between horizontal cell size and boundary layer depth seen in satellite observations for the conditions of 900–1400 m deep boundary layers. However, the 9 km simulation is unable to resolve smaller circulations corresponding to shallower boundary layers, instead producing MCC with an invariant horizontal scale for all simulated boundary layers depths. The results demonstrate that the grid spacing needed for proper simulation of the MCC structure in marine stratocumulus regions depends on the boundary layer depth.
Observed and projected urban extreme rainfall events in India
Authors: Ali Haider , Mishra Vimal , Pai D. S. 
Published: October 2014

AbstractWe examine changes in extreme rainfall indices over 57 major urban areas in India under the observed (1901–2010) and projected future climate (2010–2060). Between 1901 and 2010, only four out of the total 57 urban areas showed a significant (p‐value <0.05) increasing trend in the monsoon maximum rainfall (MMR). Time‐varying trends for the various rainfall indices exhibited that only a few urban areas experienced significant increases in the extreme rainfall indices for the different periods. Moreover, rainfall maxima for 1–10 day durations and at 100 year return period did not change significantly over the majority of urban areas in the post‐1955 period. Results do not indicate any significant change (p > 0.05) in the pooled mean and distribution of the extreme rainfall indices for the pre‐ and post‐1983 periods revealing an insignificant role of urbanization on rainfall extremes in the major urban areas in India. We find that at the majority of urban areas changes in the extreme rainfall indices are driven by large scale climate variability. Regional Climate Models (RCMs) that participated in the CORDEX‐South Asia program showed a significant bias in the monsoon maximum rainfall and rainfall maxima at 100 year return period for the majority of urban areas. For instance, most of the models fail to simulate rainfall maxima within ±10% bias, which can be considered appropriate for a storm water design at many urban areas. Rainfall maxima at 1–3 day durations and 100 year return period is projected to increase significantly under the projected future climate at the majority of urban areas in India. The number of urban areas with significant increases in rainfall maxima under the projected future climate is far larger than the number of areas that experienced significant changes in the historic climate (1901–2010), which warrants a careful attention for urban storm water infrastructure planning and management.
Statistical studies on Mars atmospheric sputtering by precipitating pickup O+: Preparation for the MAVEN mission
Authors: Wang Yung‐Ching , Luhmann Janet G. , Fang Xiaohua , Leblanc François , Johnson Robert E. , Ma Yingjuan , Ip Wing‐Huen 
Published: October 2014

AbstractWith the upcoming MAVEN mission, the role of escape in the evolution of the Martian atmosphere is investigated in more detail. This work builds on our previous modeling of the atmospheric impact of the pickup O+sputtering effects for various solar wind parameters, solar EUV intensities, and the surface crustal field distributions. Relationships between the incident ion properties and the ejected hot neutral components, often referred to as atmospheric sputtering, are derived for application to proposed MAVEN ion spectrometer measurements of precipitating O+. We show how our simulation results can be used to constrain the sputtering effects under present conditions and to interpolate toward estimates of sputtering efficiencies occurring in earlier epochs. Present‐day sputtering under typical circumstance is estimated to be weak but possibly detectable as an exospheric enhancement. The ultimate goal of estimating the importance of atmospheric sputtering effects on the evolution of the Martian atmosphere can be better deduced by the combining MAVEN measurements with models and the sputtering response relations derived here.
Steady state estimation of soil organic carbon using satellite‐derived canopy leaf area index
Authors: Fang Yilin , Liu Chongxuan , Huang Maoyi , Li Hongyi , Leung L. Ruby 
Published: October 2014

AbstractEstimation of soil organic carbon (SOC) stock using models typically requires long term spin‐up of the carbon‐nitrogen (CN) models, which has become a bottleneck for global modeling. We report a new numerical approach to estimate global SOC stock that can alleviate long spin‐up. The approach uses satellite‐based canopy leaf area index (LAI) and takes advantage of a reaction‐based biogeochemical module—Next Generation BioGeoChemical Module (NGBGC) that was recently developed and incorporated in version 4 of the Community Land Model (CLM4). Although NGBGC uses the same CN mechanisms as in CLM4CN, it can be easily configured to run prognostic or steady state simulations. The new approach was applied at point and global scales and compared with SOC derived from spin‐up by running NGBGC in the prognostic mode, and SOC from the Harmonized World Soil Database (HWSD). The steady state solution is comparable to the spin‐up value when the satellite LAI is close to that from the spin‐up solution, and largely captured the global variability of the HWSD SOC across the different dominant plant functional types (PFTs). The correlation between the simulated and HWSD SOC was, however, weak at both point and global scales, suggesting the needs for improving the biogeochemical processes described in CLM4 and updating HWSD. Besides SOC, the steady state solution also includes all other state variables simulated by a spin‐up run, which makes the tested approach a promising tool to efficiently estimate global SOC distribution and evaluate and compare multiple aspects simulated by different CN mechanisms in the model.
Synthesis of Fused Quinoline and Quinoxaline Derivatives Enabled by Domino Radical Triple Bond Insertions
Authors: Sun Xiaoyang , Li Jiahong , Ni Yunpeng , Ren Daan , Hu Zhentao , Yu Shouyun 
Published: October 2014

AbstractA practical and environmentally friendly strategy for the preparation of fused quinoline and quinoxaline derivatives has been developed, enabled by domino radical triple bond insertions. These reactions have very high regioselectivity and can be carried out under mild conditions in good to excellent chemical yields.
Scanning Electrochemical Microscopy of Individual Catalytic Nanoparticles
Authors: Sun Tong , Yu Yun , Zacher Brian J. , Mirkin Michael V. 
Published: October 2014

AbstractElectrochemistry at individual metal nanoparticles (NPs) can provide new insights into their electrocatalytic behavior. Herein, the electrochemical activity of single AuNPs attached to the catalytically inert carbon surface is mapped by using extremely small (≥3 nm radius) polished nanoelectrodes as tips in the scanning electrochemical microscope (SECM). The use of such small probes resulted in the spatial resolution significantly higher than in previously reported electrochemical images. The currents produced by either rapid electron transfer or the electrocatalytic hydrogen evolution reaction at a single 10 or 20 nm NP were measured and quantitatively analyzed. The developed methodology should be useful for studying the effects of nanoparticle size, geometry, and surface attachment on electrocatalytic activity in real‐world application environment.
Hemodialysis membrane surface chemistry as a barrier to lipopolysaccharide transfer
Authors: Madsen Ben , Britt David W. , Ho Chih‐Hu , Henrie Michael , Ford Cheryl , Stroup Eric , Maltby Brent , Olmstead Doug , Andersen Marion 
Published: October 2014

ABSTRACTDuring hemodialysis bacterial lipopolysaccharide (LPS) in contaminated dialysate solution may translocate across the hollow fiber membrane (HFM) to a patient's blood, resulting in fever and possible systemic shock. This study investigates LPS transfer across, and adsorption within, native and modified Fresenius Optiflux® F200NRepolysulfone (PS)/polyvinyl pyrrolidone (PVP) HFMs. Modifications include varied PVP content, addition of a PS‐poly(ethylene glycol) copolymer (PS‐PEG), and bleach sterilization. Under clinically relevant flow conditions LPS from >400 EU mL−1spiked dialysate is not detected (<0.1 EU mL−1) in the lumens of native fibers, but is detected to varying degrees (0.2–15 EU mL−1) in the lumens of the modified fibers. Fluorescently labeled LPS predominantly adsorbs near the lumen of all membranes except the PS‐PEG containing membrane, where LPS localizes on the outer wall. Thus, addition of PS‐PEG may entrap LPS in the HFM spongy matrix, away from the blood‐contacting fiber lumen. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2015,132, 41550.
Meta-analysis of gut barrier dysfunction in patients with acute pancreatitis
Authors: Wu L M , Sankaran S J , Plank L D , Windsor J A , Petrov M S 
Published: October 2014

Abstract

Background
The gut is implicated in the pathogenesis of acute pancreatitis but there is discrepancy between individual studies regarding the prevalence of gut barrier dysfunction in patients with acute pancreatitis. The aim of this study was to determine the prevalence of gut barrier dysfunction in acute pancreatitis, the effect of different co-variables, and changes in gut barrier function associated with the use of various therapeutic modalities.

Methods
A literature search was performed using PRISMA and MOOSE guidelines. Summary estimates were presented as pooled prevalence of gut barrier dysfunction and the associated 95 per cent c.i.

Results
A total of 44 prospective clinical studies were included in the systematic review, of which 18 studies were subjected to meta-analysis. The pooled prevalence of gut barrier dysfunction was 59 (95 per cent c.i. 48 to 70) per cent; the prevalence was not significantly affected by disease severity, timing of assessment after hospital admission or type of test used, but showed a statistically significant association with age. Overall, nine of 13 randomized clinical trials reported a significant improvement in gut barrier function following intervention compared with the control group, but only three of six studies that used standard enteral nutrition reported a statistically significant improvement in gut barrier function after intervention.

Conclusion
Gut barrier dysfunction is present in three of five patients with acute pancreatitis, and the prevalence is affected by patient age but not by disease severity. Clinical studies are needed to evaluate the effect of enteral nutrition on gut function in acute pancreatitis.
Influence of visual force feedback on tissue handling in minimally invasive surgery
Authors: Rodrigues S P , Horeman T , Sam P , Dankelman J , van den Dobbelsteen J J , Jansen F-W 
Published: October 2014

AbstractBackgroundForce feedback might improve surgical performance during minimally invasive surgery. This study sought to determine whether training with force feedback shortened the tissue-handling learning curve, and examined the influence of real-time visual feedback compared with postprocessing feedback.MethodsMedical students without experience of minimally invasive surgery were randomized into three groups: real-time force feedback, postprocessing force feedback and no force feedback (control). All performed eight suturing tasks consecutively, of which the first and eighth were the premeasurement and postmeasurement tasks respectively (no feedback). Depending on randomization, either form of feedback was given during the second to seventh task. Time, mean force non-zero and maximum force were measured with a force sensor. Results of the groups were compared with one-way ANOVA, and intragroup improvement using a paired-samples t test.ResultsA total of 72 students took part. Both intervention groups used significantly lower interaction forces than the control group during the knot-tying phase of the postmeasurement task and improved their interaction forces significantly during the knot-tying phase. The form of feedback did not influence its effectiveness.ConclusionThe tissue-handling skills of medical students improved significantly when they were given force feedback of their performance. This effect was seen mainly during the knot-tying phase of the suturing task.
Isolation and genetic analysis of an environmental bacteriophage: A 10‐session laboratory series in molecular virology
Authors: Williamson Ryan P. , Barker Brent T. , Drammeh Hamidou , Scott Jefferson , Lin Joseph 
Published: October 2014

AbstractBacterial viruses, otherwise known as bacteriophage (or phage), are some of the most abundant viruses found in the environment. They can be easily isolated from water or soil and are ideal for use in laboratory classrooms due to their ease of culture and inherent safety. Here, we describe a series of 10 laboratory exercises where students collect, isolate, and purify the genome of an environmental phage. Once the genome has been extracted, students then clone a fragment of their isolated phage genome into a plasmid and analyze its sequence to identify the phage in their original isolate. These exercises have been carefully designed to apply foundational concepts that will expose students to basic skills in microbiology, molecular biology, and bioinformatics. © 2014 by The International Union of Biochemistry and Molecular Biology, 42(6):480–485, 2014.