bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of meteoric smoke particles on the D region ion chemistry
Authors: Baumann Carsten , Rapp Markus , Anttila Milla , Kero Antti , Verronen Pekka T. 
Published: November 2015

AbstractThis study focuses on meteor smoke particle (MSP) induced effects on the D region ion chemistry. Hereby, MSPs, represented with an 11 bin size distribution, have been included as an active component into the Sodankyä Ion and Neutral Chemistry model. By doing that, we model the diurnal variation of the negatively and positively charged MSPs as well as ions and the electron density under quiet ionospheric conditions. Two distinct points in time are studied in more detail, i.e., one for sunlit conditions (Solar zenith angle is 72°) and one for dark conditions (Solar zenith angle is 103°). We find nightly decrease of free electrons and negative ions, the positive ion density is enhanced at altitudes above 80 km and reduced below. During sunlit conditions the electron density is enhanced between 60 and 70 km altitude, while there is a reduction in negative and positive ions densities. In general, the MSP influence on the ion chemistry is caused by changes in the electron density. On the one hand, these changes occur due to nightly electron scavenging by MSPs resulting in a reduced electron‐ion recombination. As a consequence positive ion density increase, especially water cluster ions are highly affected. On the other hand, the electron density is slightly increased during daytime by a MSP‐related production due to solar radiation. Thus, more electrons attach to neutrals and short‐lived negative ions increase in number density. The direct attachment of ions to MSPs is a minor process, but important for long living ions.
Concurrent observations at the magnetic equator of small‐scale irregularities and large‐scale depletions associated with equatorial spread F
Authors: Hickey Dustin A. , Martinis Carlos R. , Rodrigues Fabiano S. , Varney Roger H. , Milla Marco A. , Nicolls Michael J. , Strømme Anja , Arratia Juan F. 
Published: November 2015

AbstractIn 2014 an all‐sky imager (ASI) and an Advanced Modular Incoherent Scatter Radar consisting of 14 panels (AMISR‐14) system were installed at the Jicamarca Radio Observatory. The ASI measures airglow depletions associated with large‐scale equatorial spread F irregularities (10–500 km), while AMISR‐14 detects small‐scale irregularities (0.34 m). This study presents simultaneous observations of equatorial spread F (ESF) irregularities at 50–200 km scale sizes using the all‐sky imager, at 3 m scale sizes using the JULIA (Jicamarca Unattended Long‐term Investigations of the Ionosphere and Atmosphere) radar, and at 0.34 m scales using the AMISR‐14 radar. We compare data from the three instruments on the night of 20–21 August 2014 by locating the radar scattering volume in the optical images. During this night no topside plumes were observed, and we only compare with bottomside ESF. AMISR‐14 had five beams perpendicular to the magnetic field covering ~200 km in the east‐west direction at 250 km altitude. Comparing the radar data with zenith ASI measurements, we found that most of the echoes occur on the western wall of the depletions with fewer echoes observed the eastern wall and center, contrary to previous comparisons of topside plumes that showed most of the echoes in the center of depleted regions. We attribute these differences to the occurrence of irregularities produced at submeter scales by the lower hybrid drift instability. Comparisons of the ASI observations with JULIA images show similar results to those found in the AMISR‐14 and ASI comparison.
A global electric circuit model within a community climate model
Authors: Lucas G. M. , Baumgaertner A. J. G. , Thayer J. P. 
Published: November 2015

AbstractTo determine the complex dependencies of currents and electric fields within the Global Electric Circuit (GEC) on the underlying physics of the atmosphere, a new modeling framework of the GEC has been developed for use within global circulation models. Specifically, the Community Earth System Modeling framework has been utilized. A formulation of atmospheric conductivity based on ion production and loss mechanisms (including galactic cosmic rays, radon, clouds, and aerosols), conduction current sources, and ionospheric potential changes due to the influence of external current systems are included. This paper presents a full description of the calculation of the electric fields and currents within the model, which now includes several advancements to GEC modeling as it incorporates many processes calculated individually in previous articles into a consistent modeling framework. This framework uniquely incorporates effects from the troposphere up to the ionosphere within a single GEC model. The incorporation of a magnetospheric potential, which is generated by a separate magnetospheric current system, acts to modulate or enhance the surface level electric fields at high‐latitude locations. This produces a distinct phasing signature with the GEC potential that is shown to depend on the observation location around the globe. Lastly, the model output for Vostok and Concordia, two high‐latitude locations, is shown to agree with the observational data obtained at these sites over the same time period.
Air pollution and climate response to aerosol direct radiative effects: A modeling study of decadal trends across the northern hemisphere
Authors: Xing Jia , Mathur Rohit , Pleim Jonathan , Hogrefe Christian , Gan Chuen‐Meei , Wong David C. , Wei Chao , Wang Jiandong 
Published: November 2015

AbstractDecadal hemispheric Weather Research and Forecast‐Community Multiscale Air Quality simulations from 1990 to 2010 were conducted to examine the meteorology and air quality responses to the aerosol direct radiative effects. The model's performance for the simulation of hourly surface temperature, relative humidity, wind speed, and direction was evaluated through comparison with observations from NOAA's National Climatic Data Center Integrated Surface Data. The inclusion of aerosol direct radiative effects improves the model's ability to reproduce the trend in daytime temperature range which over the past two decades was increasing in eastern China but decreasing in eastern U.S. and Europe. Trends and spatial and diurnal variations of the surface‐level gaseous and particle concentrations to the aerosol direct effect were analyzed. The inclusion of aerosol direct radiative effects was found to increase the surface‐level concentrations of SO2, NO2, O3, SO42−, NO3−, and particulate matter 2.5 in eastern China, eastern U.S., and Europe by 1.5–2.1%, 1–1.5%, 0.1–0.3%, 1.6–2.3%, 3.5–10.0%, and 2.2–3.2%, respectively, on average over the entire 21 year period. However, greater impacts are noted during polluted days with increases of 7.6–10.6%, 6.2–6.7%, 2.0–3.0%, 7.8–9.5%, 11.1–18.6%, and 7.2–10.1%, respectively. Due to the aerosol direct radiative effects, stabilizing of the atmosphere associated with reduced planetary boundary layer height and ventilation leads to an enhancement of pollution. Consequently, the continual increase of aerosol optical depth (AOD) in eastern China leads to an increasing trend in the air quality feedback which exacerbates air pollution, while emission reductions in eastern U.S. and Europe result in a declining trend in both AODs and feedback which make the air pollution control strategies more effective.
CALIPSO‐inferred aerosol direct radiative effects: Bias estimates using ground‐based Raman lidars
Authors: Thorsen Tyler J. , Fu Qiang 
Published: November 2015

AbstractObservational constraints on the change in the radiative energy budget caused by the presence of aerosols, i.e., the aerosol direct radiative effect (DRE), have recently been made using observations from the Cloud‐Aerosol Lidar and Infrared Pathfinder Satellite (CALIPSO). CALIPSO observations have the potential to provide improved global estimates of aerosol DRE compared to passive sensor‐derived estimates due to CALIPSO's ability to perform vertically resolved aerosol retrievals over all surface types and over cloud. In this study, uncertainties in CALIPSO‐inferred aerosol DRE are estimated using multiple years of observations from the Atmospheric Radiation Measurement (ARM) program's Raman lidars at midlatitude and tropical sites. We find that CALIPSO is unable to detect all radiatively significant aerosol, resulting in an underestimate in the magnitude of the aerosol DRE by 30–50% at the two ARM sites. The undetected aerosol is likely the consequence of random noise in CALIPSO measurements and therefore will affect global observations as well. This suggests that the global aerosol DRE inferred from CALIPSO observations are likely too weak. Also examined is the impact of the ratio of extinction‐to‐backscatter (i.e., the lidar ratio) whose value CALIPSO retrievals must assume to obtain the aerosol extinction profile. It is shown that if CALIPSO can reproduce the climatological value of the lidar ratio at a given location, then the aerosol DRE there can be accurately calculated (within about 3%).
Incorporating microbial dormancy dynamics into soil decomposition models to improve quantification of soil carbon dynamics of northern temperate forests
Authors: He Yujie , Yang Jinyan , Zhuang Qianlai , Harden Jennifer W. , McGuire Anthony D. , Liu Yaling , Wang Gangsheng , Gu Lianhong 
Published: November 2015

AbstractSoil carbon dynamics of terrestrial ecosystems play a significant role in the global carbon cycle. Microbial‐based decomposition models have seen much growth recently for quantifying this role, yet dormancy as a common strategy used by microorganisms has not usually been represented and tested in these models against field observations. Here we developed an explicit microbial‐enzyme decomposition model and examined model performance with and without representation of microbial dormancy at six temperate forest sites of different forest types. We then extrapolated the model to global temperate forest ecosystems to investigate biogeochemical controls on soil heterotrophic respiration and microbial dormancy dynamics at different temporal‐spatial scales. The dormancy model consistently produced better match with field‐observed heterotrophic soil CO2 efflux (RH) than the no dormancy model. Our regional modeling results further indicated that models with dormancy were able to produce more realistic magnitude of microbial biomass (<2% of soil organic carbon) and soil RH (7.5 ± 2.4 Pg C yr−1). Spatial correlation analysis showed that soil organic carbon content was the dominating factor (correlation coefficient = 0.4–0.6) in the simulated spatial pattern of soil RH with both models. In contrast to strong temporal and local controls of soil temperature and moisture on microbial dormancy, our modeling results showed that soil carbon‐to‐nitrogen ratio (C:N) was a major regulating factor at regional scales (correlation coefficient = −0.43 to −0.58), indicating scale‐dependent biogeochemical controls on microbial dynamics. Our findings suggest that incorporating microbial dormancy could improve the realism of microbial‐based decomposition models and enhance the integration of soil experiments and mechanistically based modeling.
Statistical analysis and verification of 3‐hourly geomagnetic activity probability predictions
Authors: Wang Jingjing , Zhong Qiuzhen , Liu Siqing , Miao Juan , Liu Fanghua , Li Zhitao , Tang Weiwei 
Published: November 2015

AbstractThe Space Environment Prediction Center (SEPC) has classified geomagnetic activity into four levels: quiet to unsettled (Kp < 4), active (Kp = 4), minor to moderate storm (Kp = 5 or 6), and major to severe storm (Kp > 6). The 3‐hourly Kp index prediction product provided by the SEPC is updated half hourly. In this study, the statistical conditional forecast models for the 3‐hourly geomagnetic activity level were developed based on 10 years of data and applied to more than 3 years of data, using the previous Kp index, interplanetary magnetic field, and solar wind parameters measured by the Advanced Composition Explorer as conditional parameters. The quality of the forecast models was measured and compared against verifications of accuracy, reliability, discrimination capability, and skill of predicting all geomagnetic activity levels, especially the probability of reaching the storm level given a previous “calm” (nonstorm level) or “storm” (storm level) condition. It was found that the conditional models that used the previous Kp index, the peak value of BtV (the product of the total interplanetary magnetic field and speed), the average value of Bz (the southerly component of the interplanetary magnetic field), and BzV (the product of the southerly component of the interplanetary magnetic field and speed) over the last 6 h as conditional parameters provide a relative operating characteristic area of 0.64 and can be an appropriate predictor for the probability forecast of geomagnetic activity level.
A pseudo genetic model of coarse braided‐river deposits
Authors: Pirot Guillaume , Straubhaar Julien , Renard Philippe 
Published: November 2015

AbstractA new method is proposed to produce three‐dimensional facies models of braided‐river aquifers based on analog data. The algorithm consists of two steps. The first step involves building the main geological units. The production of the principal inner structures of the aquifer is achieved by stacking Multiple‐Point‐Statistics simulations of successive topographies, thus mimicking the major successive flooding events responsible for the erosion and deposition of sediments. The second step of the algorithm consists of generating fine scale heterogeneity within the main geological units. These smaller‐scale structures are generated by mimicking the trough‐filling process occurring in braided rivers; the imitation of the physical processes relies on the local topography and on a local approximation of the flow. This produces realistic cross‐stratified sediments, comparable to what can be observed in outcrops. The three main input parameters of the algorithm offer control over the proportions, the continuity and the dimensions of the deposits. Calibration of these parameters does not require invasive field measurements and can rely partly on analog data.
Mechanisms of growth inhibition of primary prostate epithelial cells following gamma irradiation or photodynamic therapy include senescence, necrosis, and autophagy, but not apoptosis
Authors: Frame Fiona M. , Savoie Huguette , Bryden Francesca , Giuntini Francesca , Mann Vincent M. , Simms Matthew S. , Boyle Ross W. , Maitland Norman J. 
Published: November 2015

AbstractIn comparison to more differentiated cells, prostate cancer stem‐like cells are radioresistant, which could explain radio‐recurrent prostate cancer. Improvement of radiotherapeutic efficacy may therefore require combination therapy. We have investigated the consequences of treating primary prostate epithelial cells with gamma irradiation and photodynamic therapy (PDT), both of which act through production of reactive oxygen species (ROS). Primary prostate epithelial cells were cultured from patient samples of benign prostatic hyperplasia and prostate cancer prior to treatment with PDT or gamma irradiation. Cell viability was measured using MTT and alamar blue assay, and cell recovery by colony‐forming assays. Immunofluorescence of gamma‐H2AX foci was used to quantify DNA damage, and autophagy and apoptosis were assessed using Western blots. Necrosis and senescence were measured by propidium iodide staining and beta‐galactosidase staining, respectively. Both PDT and gamma irradiation reduced the colony‐forming ability of primary prostate epithelial cells. PDT reduced the viability of all types of cells in the cultures, including stem‐like cells and more differentiated cells. PDT induced necrosis and autophagy, whereas gamma irradiation induced senescence, but neither treatment induced apoptosis. PDT and gamma irradiation therefore inhibit cell growth by different mechanisms. We suggest these treatments would be suitable for use in combination as sequential treatments against prostate cancer.
Percutaneous coronary intervention with the TandemHeart™ percutaneous left ventricular assist device support: Six years of experience and outcomes
Authors: Nascimbene Angelo , Loyalka Pranav , Gregoric Igor D. , Kar Biswajit 
Published: November 2015

ObjectivesOur study was designed to evaluate the outcomes of TandemHeart™ assistance during percutaneous coronary intervention, specifically in relationship to pre‐procedural clinical and hemodynamic risk factors in patients ineligible for surgical revascularization.BackgroundWe have used the TandemHeart™ percutaneous left ventricular assist device during percutaneous coronary intervention (PCI) in patients for whom conventional PCI and aorto‐coronary bypass would pose substantial risk owing to comorbidities and/or clinical presentations.MethodsWe retrospectively analyzed data from 626 consecutive PCIs at the Texas Heart Institute from 2005 to 2011. Among these, 74 interventions were performed with TandemHeart™ support. Mortality and morbidity were analyzed in relationship to presentation status (elective, urgent, emergent, or emergent salvage), and then we recorded outcomes and survival rates over the course of six years.ResultsAt 30 days after PCI, survival rates were 94%, 88%, 79%, and 55% in the elective, urgent, emergent, and emergent salvage groups, respectively. Survival rates at one year were at 75% in the elective, 64% in the urgent, 52% in the emergent, and 45% in the emergent salvage groups. Survival rates at 6 years were 68% in the elective, 53% in the urgent, 31% in the emergent, and 41% in the emergent salvage groups, respectively. In elective and urgent groups, successful weaning from mechanical support was possible in all patients. In the emergent and emergent salvage groups, successful weaning from mechanical support was possible in 84% and 55% of patients, respectively.ConclusionsTandemHeart™ assisted PCI is a viable option for revascularization in cases of profound cardiogenic shock or extremely risky intervention due to complex anatomy. © 2015 Wiley Periodicals, Inc.
Hydraulic performance of Winpak‐C modular catalytic structured packing
Authors: Li Jinming , Ding Huidian , Xiang Wenyu , Tao Min , Liu Chunjiang 
Published: November 2015

AbstractThe use of catalytic distillation (CD) in chemical production has gained popularity in recent years, as it results in minimized installation costs and increased efficiency. However, the design of suitable modular catalytic structured packing (MCSP) for CD processes remains a challenge. This paper presents a novel MCSP named Winpak‐C. The hydraulic performance of Winpak‐C is investigated in a 400‐mm diameter column with an air‐water system. Predictive models for the pressure drop and liquid holdup are proposed, which provide reasonably close predictions. The models describe the gas loading point, which reflects the transition from the liquid loading regime to the unstable flooding regime. Further, a visual experiment is performed to determine the maximum liquid load of the catalyst‐containing bags, and the flow behaviours around the liquid load point are described. In addition, a tracer method is employed to determine the liquid residence time distribution (RTD). The Peclet number and axial dispersion coefficient deduced from RTD curves are discussed and compared with those for traditional MCSP. This study on the hydraulics of Winpak‐C is significant for the design and scale‐up of CD processes.
Dense motion field estimation from myocardial boundary displacements
Authors: Morais Pedro , Queirós Sandro , Ferreira Adriano , Rodrigues Nuno F. , Baptista Maria J. , D'hooge Jan , Vilaça João L. , Barbosa Daniel 
Published: November 2015

SummaryMinimally invasive cardiovascular interventions guided by multiple imaging modalities are rapidly gaining clinical acceptance for the treatment of several cardiovascular diseases. These images are typically fused with richly detailed pre‐operative scans through registration techniques, enhancing the intra‐operative clinical data and easing the image‐guided procedures. Nonetheless, rigid models have been used to align the different modalities, not taking into account the anatomical variations of the cardiac muscle throughout the cardiac cycle.In the current study, we present a novel strategy to compensate the beat‐to‐beat physiological adaptation of the myocardium. Hereto, we intend to prove that a complete myocardial motion field can be quickly recovered from the displacement field at the myocardial boundaries, therefore being an efficient strategy to locally deform the cardiac muscle. We address this hypothesis by comparing three different strategies to recover a dense myocardial motion field from a sparse one, namely, a diffusion‐based approach, thin‐plate splines, and multiquadric radial basis functions.Two experimental setups were used to validate the proposed strategy. First, an in silico validation was carried out on synthetic motion fields obtained from two realistic simulated ultrasound sequences. Then, 45 mid‐ventricular 2D sequences of cine magnetic resonance imaging were processed to further evaluate the different approaches.The results showed that accurate boundary tracking combined with dense myocardial recovery via interpolation/diffusion is a potentially viable solution to speed up dense myocardial motion field estimation and, consequently, to deform/compensate the myocardial wall throughout the cardiac cycle. Copyright © 2015 John Wiley & Sons, Ltd.
Moss and peat hydraulic properties are optimized to maximize peatland water use efficiency
Authors: Kettridge N. , Tilak A. S. , Devito K. J. , Petrone R. M. , Mendoza C. A. , Waddington J. M. 
Published: November 2015

AbstractPeatland ecosystems are globally important carbon and terrestrial surface water stores that have formed over millennia. These ecosystems have likely optimized their ecohydrological function over the long‐term development of their soil hydraulic properties. The optimization of peat hydraulic properties is examined to determine which of the following conditions peatland ecosystems target during this development: (i) maximize carbon accumulation, (ii) maximize water storage, or (iii) balance carbon profit across hydrological disturbances. To identify this control, the short‐term hydrological response of a 0.5‐m‐deep peat profile was simulated during a 50‐day rain‐free period. A total of 5000 Monte‐Carlo model realizations were conducted, with peat hydraulic properties differing between each realization (values derived from known probability distributions). Saturated hydraulic conductivity (Ks) and empirical van Genuchten water retention parameter α were shown to provide a first order control on simulated water tensions. For hypothetical combinations of Ks and α, the probability that water tension exceeds the ecologically important threshold of 100 mb within 24 h showed a bimodal distribution. A peak at high probabilities was associated with profiles of high Ks and low α. Such a profile is optimized for water storage. A peak at low probabilities is associated with low Ks, high α, and is optimized for carbon accumulation. Actual hydraulic properties from five northern peatlands fall between this binominal distribution, balancing the competing demands of carbon accumulation and water storage. We argue that peat hydraulic properties are thus optimized to maximize water use efficiency and that this optimization occurs over a centennial to millennial timescale. Copyright © 2015 John Wiley & Sons, Ltd.