bluuebunny/crossref_metadata_2025_split huggingface dataset:
Exercise capacity, physical activity, and health-related quality of life in adults with CHD
Authors: Ashman Kröönström Linda , Cider Åsa , Zetterström Anna-Klara , Johansson Linda , Eriksson Peter , Brudin Lars , Dellborg Mikael 
Published: April 2020

AbstractObjectives:The aim of this study was to assess exercise capacity, physical activity, and health-related quality of life within a broad and unselected group of adults with CHD.Design:From April 2009 to February 2014, 1310 patients were assessed for suitability to participate in this single-centre cross-sectional study. Seven hundred and forty-seven (57%) patients were included, performed a submaximal bicycle test, and answered questionnaires regarding physical activity and health-related quality of life. Exercise capacity, physical activity, and health-related quality of life were compared with reference values and correlations were studied.Results:The exercise capacities of men and women with CHD were 58.7 and 66.3%, respectively, of reference values. Approximately, 20–25% of the patients did not achieve the recommended amount of physical activity. In addition, men scored significantly less points on 7 out of 10 scales of health-related quality of life and women in 6 out of 10 scales, compared with reference values. The strongest correlation was between exercise capacity and the Short Form-36 (physical function).Conclusions:Exercise capacity was impaired in all adults with CHD, including those with less complicated CHD. One-quarter of the patients did not achieve the recommended levels of physical activity. Exercise tests followed by individualised exercise prescriptions may be offered to all patients with CHD aiming to increase exercise capacity, levels of physical activity, improve health-related quality of life, and reduce the risk of acquired life-style diseases.
ONE-DIMENSIONAL CHAOTIC LAMINAR FLOW WITH COMPETITIVE EXOTHERMIC AND ENDOTHERMIC REACTIONS
Authors: WATT S. D. , HUANG Z. , SIDHU H. S. , MCINTOSH A. C. , BRINDLEY J. 
Published: April 2020

AbstractWe consider the numerical solution of competitive exothermic and endothermic reactions in the presence of a chaotic advection flow. The resulting behaviour is characterized by a strong dependence on the competitive reaction history. The burnt temperature is not immediately connected to simple enthalpy calculations, so there is a subtlety in the interplay between the major parameters, notably the Damköhler number, the ratio of the heats of exothermic and endothermic reactions, as well as the ratio of their respective activation energies. This paper seeks to explore the way these parameters affect the steady states of these reaction fronts and their stability.
A review on circularly polarized antennas, trends and advances
Authors: Banerjee Utsab , Karmakar Anirban , Saha Anuradha 
Published: April 2020

AbstractThis literature presents a comprehensive, technical review of circularly polarized (CP) antennas for different applications in wireless communication, emphasizing on the recent developments in the concerned research. The article also presents a comparative study of various works reported in the open literature, with an aim to highlight the contribution of CP antenna systems in the chronological development of the wireless communication technology. The primary motive of this review is to (a) highlight the methodologies used by different researchers to portray and analyze the different aspects in which CP antennas find their applications in modern-day wireless communication, (b) provide a practical viewpoint of the future scope of the study, based upon the past and present state-of-art research trends and (c) provide a conceptual and technical support to present-day antenna designers to help the process of furtherance of innovation and multiple system integration. In conclusion, the article also throws some light upon the future scope of research in the vast domain of CP antenna applications.
A rectangular slot antenna with perfectly conducting superstrate and reflector sheets for superior radiation in the 6–9 GHz band
Authors: Kumar Ritish , Praveen Kumar A. V. 
Published: April 2020

AbstractThis paper presents the design and analysis of a rectangular slot antenna for producing a directional radiation pattern over a wide bandwidth of 6–9 GHz. A basic wideband slot antenna is designed for the desired frequency band by microstrip offset feed technique. This antenna is then loaded with a superstrate and a reflector, both made of conducting sheets. Analogous to a three-element Yagi antenna, the superstrate enhances the boresight gain, while the reflector improves the front-to-back ratio (FBR) of the basic slot antenna. The antenna is optimized for superior wideband performance with boresight gain ≥5 dBi, peak cross-pol level ≤−10 dB and FBR ≥10 dB, over the −10 dB impedance band of 6–9 GHz, which in this paper is termed as the radiation bandwidth. Prototype measurement demonstrates a radiation bandwidth of 6.05–8.22 GHz (or 30.41%), which is in decent agreement with the simulation.
Integrating cover crops for weed management in the semiarid U.S. Great Plains: opportunities and challenges
Authors: Kumar Vipan , Obour Augustine , Jha Prashant , Liu Rui , Manuchehri Misha R. , Dille J. Anita , Holman John , Stahlman Phillip W. 
Published: April 2020

AbstractThe widespread evolution of herbicide resistance in weed populations has become an increasing concern for no-tillage (NT) growers in semiarid regions of the U.S. Great Plains. Lack of cost-effective and alternative new herbicide sites of action further exacerbates the problem of herbicide-resistant (HR) weeds and threatens the long-term sustainability of prevailing cropping systems in the region. A recent decline in commodity prices and increasing herbicide costs to manage HR weeds has spurred research efforts to build a strong rationale for developing ecologically based integrated weed management (IWM) strategies in the U.S. Great Plains. Integration of cover crops (CCs) in NT dryland production systems potentially offers several ecosystem services, including weed control, soil health improvement, decline in selective pest pressure, and overall reduction in pest management inputs. This review article aims to document the role of CCs for IWM, with emphasis on exploring emerging weed issues; ecological, economic, and agronomic benefits of growing CCs; and constraints preventing adoption of CCs in NT cropping systems in the semiarid Great Plains. We attempt to focus on changes in weed management practices, their long-term impacts on weed seedbanks, weed shifts, and herbicide-resistance evolution in the most common weed species in the region. We also highlight current knowledge gaps and propose new research priorities based on an improved understanding of CC management strategies that will ultimately aid in achieving sustainable weed management goals and preserving natural resources in water-limited environments.
Quantifying Atmospheric Trace Element Deposition Over the Ocean on a Global Scale With Satellite Rainfall Products
Authors: Kadko David , Landing William M. , Buck Clifton S. 
Published: April 2020

AbstractAtmospheric input of trace element micronutrients to the oceans is difficult to determine, as even with collection of high‐quality aerosol chemical concentrations, such data by themselves cannot yield deposition rates. To transform these concentrations into rates, a method of determining flux by applying an appropriate deposition velocity is required. A recently developed method based on the natural radionuclide 7Be has provided a means to estimate the bulk (wet + dry) deposition velocity (Vb) required for this calculation. Here, water column 7Be inventories and aerosol 7Be concentrations collected during the 2018 US GEOTRACES Pacific Meridional Transect are presented. We use these data together with those from other ocean basins to derive a global relationship between rain rate (m/yr) and bulk deposition velocity (m/day), such that Vb = 999 ± 96 × Rain rate + 1,040 ± 136 (R2 = 0.81). Thus, with satellite‐derived rainfall estimates, a means to calculate aerosol bulk deposition velocities is provided.
Statistical Analysis of Equatorial Plasma Irregularities Retrieved From Swarm 2013–2019 Observations
Authors: Aa Ercha , Zou Shasha , Liu Siqing 
Published: April 2020

AbstractIn this study, we present a statistical analysis of equatorial plasma irregularities (EPIs) by using in situ plasma density measurements of the Swarm constellation from December 2013 to December 2019. The occurrence patterns for both postsunset and postmidnight EPIs with respect to longitude, season, local time, latitude, solar activity, and geomagnetic activity level are investigated. The main findings are as follows: (1) The postsunset/postmidnight EPIs occurrence rates exhibit different longitudinal and seasonal dependence: The postsunset EPIs have the maximum occurrence rate over the American‐Atlantic sectors during the December solstice and equinoxes, and the postmidnight EPIs have the maximum occurrence rate during the June solstice, especially over the African sector. (2) The postsunset EPIs occurrence rates have a positive correlation with solar activity, while the postmidnight EPIs are negatively correlated with it. (3) The latitudinal distribution of EPIs exhibits a double‐peak structure around ±5° magnetic latitude with a more significant peak in the summer hemisphere. (4) The EPIs occurrence rate increases with increasing geomagnetic activity level. (5) The main controlling factors for the distribution of postsunset EPIs are the magnetic declination angle, equatorial vertical E × B drift, and thermospheric zonal wind. For the postmidnight EPIs, the main controlling factors are likely to be atmospheric gravity waves and equatorward thermospheric meridional wind associated with midnight temperature maximum.
Magnetic Field Measurements From Rome During the August–September 1859 Storms
Authors: Blake Seán P. , Pulkkinen Antti , Schuck Peter W. , Nevanlinna Heikki , Reale Oreste , Veenadhari Bhaskara , Mukherjee Shyamoli 
Published: April 2020

AbstractThe geomagnetic storm (or “Carrington event”) of 1–2 September 1859 is one of the largest geomagnetic disturbances on record. At the time, it caused widespread disruption to telegraph systems and was accompanied by aurorae seen overhead as far south as ∼29° magnetic latitude. The magnitude of the Carrington event means it remains a popular subject of study in the field of space weather, despite the sparse magnetic measurements available from the time. One set of measurements that is available is from the Rome observatory (“Collegio Romano,” magnetic latitude ∼38.6°). Here we transcribe these horizontal magnetic field data and convert them to nanoteslas. We find that the device used at Rome had an operational range of around 305 nT. Despite going off‐scale during the storm, the magnetometer at Rome recorded changes of hundreds of nanoteslas per minute and tens of nanoteslas per second in the horizontal magnetic field. Apart from the tabulated data, we also examine the reported off‐scale deviation of 3,000 nT at Rome during the storm. While we could not explicitly locate this reported deviation in the tabulated data, we find that this deviation is comparable to magnetic variations seen at auroral latitudes for modern large magnetic storms, indicating that Rome was in the auroral oval during the morning of 2 September 1859. By comparing this large off‐scale deviation to modern geomagnetic data, we estimate that Rome may have experienced a maximum change of 420 nT min−1.
Simultaneous Observations of ELF/VLF Rising‐Tone Quasiperiodic Waves and Energetic Electron Precipitations in the High‐Latitude Upper Ionosphere
Authors: Zhima Zeren , Huang Jianping , Shen Xuhui , Xia Zhiyang , Chen Lunjin , Piersanti Mirko , Yang Yanyan , Wang Qiao , Zeng Li , Lei Jungang , Chu Wei , Yan Rui , Zhao Shufan , Hu Yunpeng , Guo Feng 
Published: April 2020

AbstractThe quasiperiodic (QP) waves accompanied by simultaneous energetic electron precipitations in the high‐latitude ionosphere were recorded by the sun‐synchronous circular orbit China Seismo‐Electromagnetic Satellite (CSES). The new features of QP waves observed by CSES are the well‐pronounced rising‐tone structures and very short repetition periods, which are not ofen reported by previous studies. The repetition period of QP waves varies from ~1 to over 20 s, with wave spectral properties displaying dynamic structures and clear cutoff frequencies. The majority of QP waves appear at geomagnetic latitudes from ~50° to 65°, and L shell from ~3.5 to 4, mostly inside the plasmapause. The QP waves obliquely propagate towards decreasing L shell directions with right‐handed polarization, with wave normal angles varying from ~30° to 50°. Out of the 68 events examined, 19 of them show synchronous variations of ultralow frequency (ULF) magnetic field pulsations in certain portions of the wave event. The energetic electrons predominately precipitate in a double‐peak pattern (~400 to 550 keV and ~700 to 800 keV). No clear periodic precipitating fluxes were found. The estimated time interval of energetic electrons driving free energy to modulate the whistler‐mode waves varies from 0.04 to 30°s, which is roughly consistent with the observed repetition periods (10 to over 20 s). For the fast repetition period (~1 to 2s) QP wave, it is likely caused by the bouncing of the extremely/very low frequency (ELF/VLF) whistler‐mode wave packets from the conjugate ionosphere.
Planetary Wave (PW) Generation in the Thermosphere Driven by the PW‐Modulated Tidal Spectrum
Authors: Forbes Jeffrey M. , Zhang Xiaoli , Maute Astrid 
Published: April 2020

AbstractThe National Center for Atmospheric Research thermosphere‐ionosphere‐electrodynamics general circulation model (TIE‐GCM) is used to conduct numerical experiments that isolate and elucidate a substantial modification of the quasi‐6‐day wave (Q6DW) above 110 km due to presence of the planetary wave (PW)‐modulated tidal spectrum. A two‐stage nonlinear tidal interaction is proposed, and its role in vertical coupling by the Q6DW is quantified. The theory enables calculation of net Q6DW accelerations and heating rates in the height‐latitude domain (90–300 km; ±75°) due to wave‐wave interactions of up to 10 ms−1 day−1 and 8 K day−1, respectively. The Global‐Scale Wave Model (GSMW) is used to demonstrate that these forcings produce Q6DW zonal and meridional wind amplitudes, and temperatures, of order 5–20 ms−1, 5–15 ms−1, and 5–10 K, respectively. Notably, Q6DW thermal forcing in the GSWM accounts for near‐doubling of the wind magnitudes calculated with momentum forcing alone. The computed values are comparable to the 10–22 ms−1, 3–12 ms−1, and 4–12 KQ6DW amplitudes calculated with lower‐boundary forcing of the Q6DW also included. The proposed two‐stage interaction plausibly impacts other PW wind structures in the dynamo region and thus how PW in general participate in atmosphere‐ionosphere coupling.
Statistical Comparisons of Temperature Variance and Kinetic Energy in Global Ocean Models and Observations: Results From Mesoscale to Internal Wave Frequencies
Authors: Luecke Conrad A. , Arbic Brian K. , Richman James G. , Shriver Jay F. , Alford Matthew H. , Ansong Joseph K. , Bassette Steven L. , Buijsman Maarten C. , Menemenlis Dimitris , Scott Robert B. , Timko Patrick G. , Voet Gunnar , Wallcraft Alan J. , Zamudio Luis 
Published: April 2020

AbstractTemperature variance and kinetic energy (KE) from two global simulations of the HYbrid Coordinate Ocean Model (HYCOM; 1/12° and 1/25°) and three global simulations of the Massachusetts Institute of Technology general circulation model (MITgcm; 1/12°, 1/24°, and 1/48°), all of which are forced by atmospheric fields and the astronomical tidal potential, are compared with temperature variance and KE from a database of about 2,000 moored historical observations (MHOs). The variances are computed across frequencies ranging from supertidal, dominated by the internal gravity wave continuum, to subtidal, dominated by currents and mesoscale eddies. The most important qualitative difference between HYCOM and MITgcm, and between simulations of different resolutions, is in the supertidal band, where the 1/48° MITgcm lies closest to observations. Across all frequency bands examined, the HYCOM simulations display higher spatial correlation with the MHO than do the MITgcm simulations. The supertidal, semidiurnal, and diurnal velocities in the HYCOM simulations also compare more closely with observations than do the MITgcm simulations in a number of specific continental margin/marginal sea regions. To complement the model‐MHO comparisons, this paper also compares the surface ocean geostrophic eddy KE in HYCOM, MITgcm, and a gridded satellite altimeter product. Consistent with the model‐MHO comparisons, the HYCOM simulations have a higher spatial correlation with the altimeter product than the MITgcm simulations do. On the other hand, the surface ocean geostrophic eddy KE is too large, relative to the altimeter product, in the HYCOM simulations.
Seasonal and Interannual Variations in Nitrogen Availability and Particle Export in the Northwestern North Pacific Subtropical Gyre
Authors: Mino Y. , Sukigara C. , Honda M. C. , Kawakami H. , Wakita M. , Sasaoka K. , Yoshikawa C. , Abe O. , Kaiser J. , Kimoto K. , Kitamura M. , Fujiki T. , Matsumoto K. , Saino T. 
Published: April 2020

AbstractTime series of particulate nitrogen isotope delta (PN‐δ15N) and flux of trapped particles at 200 m were determined in the northwestern North Pacific subtropical gyre between 2010 and 2014 in order to examine temporal variations in mixed layer nitrate availability and downward particle export. Lower PN‐δ15N (<4‰) seen every winter corresponded to convective nitrate supply triggering phytoplankton blooms. Greater particle fluxes were associated with higher CaCO3 concentrations (mass fraction >50%), implying that new nitrogen supply stimulated predominantly coccolithophore growth and downward transport of coccoliths. Even in the stratified summer of 2011, a δ15N drop associated with a spike in particulate flux was found and was attributed to the uplift of nitrate‐rich deep waters due to a mesoscale cyclonic eddy passing the mooring station. Total nitrate input sustains 86–93% of annual new production in this region while nitrogen fixation accounts for the rest. Trapped particles also showed that the winter δ15N decrease appeared earlier in the 2011–2012 blooms than those in 2013–2014, coinciding with 8% higher CaCO3 concentrations and a 40% lower particulate organic carbon to inorganic carbon export ratio, R(POC:PIC). This reflected stronger convective mixing and hence larger nutrient supply in 2011–2012, caused by larger ocean heat loss related to winter monsoon intensity. Such interannual change of winter R(POC:PIC) can affect CO2 uptake rate in the northwestern North Pacific subtropical gyre where anthropogenic CO2 accumulates in subtropical mode waters.
Decadal Wintertime Temperature Changes in East Asia During 1958–2001 and the Contributions of Internal Variability and External Forcing
Authors: Luo M. , Feng J.M. , Xu Z.F. , Chen L. , Wang J. , Wang Y.L. , Lin S. , Zhong L.H. 
Published: April 2020

AbstractThe winter temperature in East Asia from 1958 to 2001 has shown an obvious warming trend superposed with a large amplitude of decadal oscillations. To separate the relative contributions of external forcing and internal variability to the decadal change in winter temperature, we propose a method which combines reanalysis data, global atmosphere‐ocean coupled model outputs, and regional climate model. The results show that the weakening of the East Asian winter monsoon accounts for warming trend in the south Mongolia, the southeastern coast of Asia, and the adjacent seas to a large extent. In contrast, radiative forcing causes the warming trend in middle and high latitudes. The increasing concentration of aerosols could have resulted in local cooling in some areas. The winter temperature shows a decadal oscillation of 0.6 °C at a time scale of 8–20 a, which is mainly due to the oscillation of the Siberian‐Mongolia High and volcanic activities. The amplitude of temperature oscillations caused by volcanic activities was one third of that induced by the Siberian‐Mongolia High.
Temporal‐Geochemical Evolution of the Persani Volcanic Field, Eastern Transylvanian Basin (Romania): Implications for Slab Rollback Beneath the SE Carpathians
Authors: Ducea Mihai N. , Barla Anca , Stoica Adriana M. , Panaiotu Cristian , Petrescu Lucian 
Published: April 2020

AbstractThe Quaternary Persani volcanic field (PVF) consists of alkali basalts formed in an extensional basin at the SE end of the Transylvanian basin, near an important anomaly in the European mantle, the Vrancea slab, a seismically active near‐vertical lithospheric fragment of debated origin. The PVF is the only basaltic field regionally, has been studied geochemically in the past, and is also known for the presence of abundant mantle xenoliths. Here, we describe new geochemical data on rocks recently dated by Ar‐Ar chronometry and show that while we can reproduce virtually all previous results, there is a clear temporal evolution of the magmatic system. There is an increase of over 80°C in temperatures determined by the Si activity thermometer, from 1,300°C to 1,380°C during the ~0.5‐Myr duration of volcanic activity, which is accompanied by several coherent trends in geochemistry, among which the decrease of Zn/Fe and 87Sr/86Sr ratios over time. Earlier, higher Zn/Fe ratios are indicative of a pyroxenite/eclogite‐dominated source, which gradually changed to a peridotite‐dominated source. These characteristics are typical of a dynamic mantle in which vertical mantle lithosphere tectonics, either due to slab rollback or mantle dripping plays a role and are not consistent with simple decompression melting of asthenosphere. Synchronous adakitic rocks found about 25–30 km east of PVF are presumed to be slab melts and are consistent with the Vrancea slab rollback as the trigger for mantle melting responsible for the PVF.
Improving SWE Estimation With Data Assimilation: The Influence of Snow Depth Observation Timing and Uncertainty
Authors: Smyth Eric J. , Raleigh Mark S. , Small Eric E. 
Published: April 2020

AbstractSnow depth observations can be leveraged with data assimilation (DA) to improve estimation of snow density and snow water equivalent (SWE). A key consideration for mission and campaign design is how snow depth retrieval characteristics (including observation timing/frequency and sampling error) influence SWE accuracy and uncertainty in a DA framework. To quantify these effects, we implement a particle filter (PF) assimilation technique to assimilate depth and validate this approach against observed snow density and SWE at 49 snow telemetry sites across 9 years. We sample from continuous in situ snow depth records to test a range of measurement timing and sampling error scenarios representative of remote sensing capabilities. Assimilation reduces density bias by over 40% and SWE bias by over 70% across climate zones and in both wet and dry years. There is little incremental benefit to SWE accuracy when assimilating more than one depth observation near peak accumulation. SWE estimates are less sensitive to observation timing than sampling error. Alternatively, more frequent depth observations improve melt‐out date timing and reduce SWE uncertainty, a key consideration when evaluating the operational utility of DA. In matching depth observations, the PF mostly acts to increase model precipitation inputs, while not systematically shifting other parameter values or forcings across the climate zones represented with the study sites. This demonstrates that precipitation is the largest source of model error. With DA, density errors are still nontrivial (above 10%), illuminating the need for further improvements to modeled density to estimate SWE within specified error limits.