bluuebunny/crossref_metadata_2025_split huggingface dataset:
Exacerbated nitrogen limitation ends transient stimulation of grassland productivity by increased precipitation
Authors: Ren Haiyan , Xu Zhuwen , Isbell Forest , Huang Jianhui , Han Xingguo , Wan Shiqiang , Chen Shiping , Wang Ruzhen , Zeng De‐Hui , Jiang Yong , Fang Yunting 
Published: March 2017

AbstractGiven that plant growth is often water‐limited in grasslands, it has been proposed that projected increases in precipitation could increase plant productivity and carbon sequestration. However, the existing evidence for this hypothesis comes primarily from observational studies along natural precipitation gradients or from short‐term manipulative experiments. It remains unclear whether long‐term increased precipitation persistently stimulates grassland productivity. In the world's largest remaining temperate grassland, we found that experimentally increased precipitation enhanced net primary production, soil‐available nitrogen and foliar nitrogen concentrations during the first six years, but it ceased to do so in the following four years, unless nitrogen was simultaneously added with water. The 15N enrichment of plant and soil nitrogen pools in later years indicates increased nitrogen losses, which exacerbated nitrogen limitation and ended the stimulation of productivity by increased precipitation. Changes in species abundance might have contributed little to the changes in water treatment effects. Our study demonstrates that the long‐term response of grassland ecosystems to increased precipitation will be mediated by nitrogen availability. Our results also point to a shift from co‐limitation by water and nitrogen early to perhaps limitation by nitrogen only later in this temperate grassland, highlighting significant variations in the type of resource limitation induced by climate change.
Performance of Automated Speech Scoring on Different Low‐ to Medium‐Entropy Item Types for Low‐Proficiency English Learners
Authors: Loukina Anastassia , Zechner Klaus , Yoon Su‐Youn , Zhang Mo , Tao Jidong , Wang Xinhao , Lee Chong Min , Mulholland Matthew 
Published: March 2017

AbstractThis report presents an overview of the SpeechRaterSM automated scoring engine model building and evaluation process for several item types with a focus on a low‐English‐proficiency test‐taker population. We discuss each stage of speech scoring, including automatic speech recognition, filtering models for nonscorable responses, and scoring model building and evaluation and compare how the performance at each step differs between different item types. We conclude by discussing the effect of item type on automated scoring performance. We also give recommendations about what considerations should be taken into account when developing tests for low‐proficiency English speakers to obtain reliable scores from an automatic scoring engine.
Young‐onset Alzheimer dementia: a comparison of Brazilian and Norwegian carers' experiences and needs for assistance
Authors: Dourado M.C.N. , Laks J. , Kimura N.R. , Baptista M.A.T. , Barca M.L. , Engedal K. , Tveit B. , Johannessen A. 
Published: March 2017

ObjectivesAlthough dementia typically occurs in older people, it can also emerge in people aged younger than 65 years in the form of young‐onset dementia, the most common type of which is Alzheimer's disease (AD). However, few studies have examined the needs of persons with young‐onset AD (YO‐AD) and their families, and cross‐cultural research on the topic is even scarcer. In response, we investigated the situations, experiences and needs for assistance of carers of persons with YO‐AD in Brazil and Norway.MethodsAs part of our qualitative study, we formed a convenience sample of Brazilian (n = 9; 7 women) and Norwegian carers (n = 11; 6 women) in 2014 and 2015, respectively, and analysed data in light of a modified version of grounded theory.ResultsCarers' narratives from both countries revealed five common themes in terms of how YO‐AD affected carers' psychological and emotional well‐being, physical well‐being, professional and financial well‐being, social lives and need for support services.ConclusionsThe infrequent differences between carers of persons with YO‐AD in Brazil and Norway indicate that carers' problems are highly similar regardless of cultural differences and public services provided. Copyright © 2017 John Wiley & Sons, Ltd.
Assessment of changes in atmospheric dynamics and dust activity over southwest Asia using the Caspian Sea–Hindu Kush Index
Authors: Kaskaoutis D. G. , Rashki A. , Houssos E. E. , Legrand M. , Francois P. , Bartzokas A. , Kambezidis H. D. , Dumka U. C. , Goto D. , Takemura T. 
Published: March 2017

ABSTRACTThis study examines the influence of the Caspian Sea–Hindu Kush Index (CasHKI) on local and synoptic meteorology as well as on dust emissions over southwest (SW) Asia by means of National Center for Environmental Prediction/National Center for Atmospheric Research (NCEP‐NCAR) re‐analysed mean sea‐level pressure (MSLP), geopotential height at 700 hPa and surface meridional wind, along with meteorological data at Zabol, east Iran and Meteosat/Infrared Difference Dust Index (IDDI) retrievals. The analysis focuses on the summer period (June to September) of 2000–2014 and the winter period (November to March) of 1963–2014. The CasHKI values are mostly controlled by the MSLP anomalies over the Caspian Sea (CS) domain, varying from approximately −25 to +35 hPa in winter and from approximately−10 to +14 hPa in summer, but without a clear annual pattern. The CasHKI values are classified into four modes for each month depending on their intensity. In the summer months, the high CasHKI mode is associated with enhanced MSLP over central Asia and deepening of the Indo‐Pakistan thermal low associated with the Indian summer monsoon. At 700‐hPa level, the high CasHKI mode shows an enhancement of the Arabian ridge, expanding it to the north over Iran and the CS, with a concurrent strengthening of the Indian trough, leading to intensification of northerly winds along east Iran. This results in significant increase in dust activity over SW Asia, which is also apparent in the winter months. Furthermore, the intensification of the northerly flow associated with the high CasHKI modes drops the temperature and increases the relative humidity over Zabol, especially during winter. The SPRINTARS‐model simulations also show increased dust emissions and concentrations for the high CasHKI values, confirming that the CasHKI variations modulate the dust activity over SW Asia throughout the year.
Diversity and activity of nitrogen‐fixing communities across ocean basins
Authors: Gradoville Mary R. , Bombar Deniz , Crump Byron C. , Letelier Ricardo M. , Zehr Jonathan P. , White Angelicque E. 
Published: March 2017

AbstractRecent observations of N2 fixation rates (NFR) and the presence of nitrogenase (nifH) genes from heterotrophic N2‐fixing (diazotrophic) prokaryotes in unusual habitats challenge the paradigm that pelagic marine N2 fixation is constrained to cyanobacteria in warm, oligotrophic, surface waters. Here, we compare NFR and diazotrophic diversity (assessed via high‐throughput nifH sequencing) from a region known to be dominated by cyanobacterial diazotrophs (the North Pacific Subtropical Gyre, NPSG) to two regions dominated by heterotrophic diazotrophs: the Eastern South Pacific (ESP, from the Chilean upwelling system to the subtropical gyre) and the Pacific Northwest coastal upwelling system (PNW). We observed distinct biogeographical patterns among the three regions. Diazotrophic community structure differed strongly between the NPSG, dominated by cyanobacterium UCYN‐A, and the ESP, dominated by heterotrophic nifH group 1J/1K, yet surface NFR were similar in magnitude (up to 5.1 nmol N L−1 d−1). However, while diverse, predominantly heterotrophic nifH genes were recovered from the PNW and the mesopelagic of the NPSG, NFR were undetectable in both of these environments (although glucose amendments stimulated low rates in the deep NPSG). Our work suggests that while diazotrophs may be nearly omnipresent in marine waters, the activity of this functional group is regionally restricted. Further, we show that the detection limits of the 15N2 fixation assay suggest that many of the low NFR reported for the mesopelagic (often < 0.1 nmol N L−1 d−1 in the literature) are not indicative of active diazotrophy, highlighting the challenges of assessing the ecosystem significance of heterotrophic diazotrophs.
In Situ FT‐IR Spectroscopy Investigation of the Water Sorption of Amphiphilic PDMS Crosslinked Networks
Authors: La Manna Pietro , Musto Pellegrino , Galli Giancarlo , Martinelli Elisa 
Published: March 2017

An amphiphilic poly(dimethyl siloxane) (PDMS) network is obtained by incorporation of poly(ethylene glycol) hydrophilic side chains within the hydrophobic matrix with the objective of improving the water affinity characteristics of the unmodified PDMS network. Sorption of water as a function of relative pressure of water vapor is investigated by in situ Fourier‐transform infrared (FT‐IR) spectroscopy. This experimental technique supplies information on the molecular interaction established between the penetrant and the polymer substrate and identifies the occurrence of self‐association between water molecules (clustering). Self‐association of penetrant increases with the concentration of water in the amphiphilic network. The overall diffusivity slightly decreases with increasing water concentration, likely due to the clustering effect. The maximum amount of water sorbed at equilibrium is low (<0.3 wt%), but significantly larger than that of the unmodified network.
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Response of the rhizosphere prokaryotic community of barley (Hordeum vulgare L.) to elevated atmospheric CO2 concentration in open‐top chambers
Authors: Szoboszlay Márton , Näther Astrid , Mitterbauer Esther , Bender Jürgen , Weigel Hans‐Joachim , Tebbe Christoph C. 
Published: March 2017

AbstractThe effect of elevated atmospheric CO2 concentration [CO2] on the diversity and composition of the prokaryotic community inhabiting the rhizosphere of winter barley (Hordeum vulgare L.) was investigated in a field experiment, using open‐top chambers. Rhizosphere samples were collected at anthesis (flowering stage) from six chambers with ambient [CO2] (approximately 400 ppm) and six chambers with elevated [CO2] (700 ppm). The V4 region of the 16S rRNA gene was PCR‐amplified from the extracted DNA and sequenced on an Illumina MiSeq instrument. Above‐ground plant biomass was not affected by elevated [CO2] at anthesis, but plants exposed to elevated [CO2] had significantly higher grain yield. The composition of the rhizosphere prokaryotic communities was very similar under ambient and elevated [CO2]. The dominant taxa were Bacteroidetes, Actinobacteria, Alpha‐, Gamma‐, and Betaproteobacteria. Elevated [CO2] resulted in lower prokaryotic diversity in the rhizosphere, but did not cause a significant difference in community structure.
Whole exome sequencing of a patient with suspected mitochondrial myopathy reveals novel compound heterozygous variants in RYR1
Authors: Blackburn Patrick R. , Selcen Duygu , Gass Jennifer M. , Jackson Jessica L. , Macklin Sarah , Cousin Margot A. , Boczek Nicole J. , Klee Eric W. , Dimberg Elliot L. , Kennelly Kathleen D. , Atwal Paldeep S. 
Published: March 2017

AbstractBackgroundPathogenic variants in ryanodine receptor 1 (RYR1, MIM# 180901) are the cause of congenital myopathy with fiber‐type disproportion, malignant hyperthermia susceptibility type 1, central core disease of muscle, multiminicore disease and other congenital myopathies.MethodsWe present a patient with global developmental delay, hypotonia, myopathy, joint hypermobility, and multiple other systemic complaints that were noted early in life. Later she was found to have multiple bone deformities involving her spine, with severe scoliosis that was corrected surgically. She was also diagnosed with ophthalmoplegia, chronic hypercapnic respiratory failure, and hypertension. At 22 years of age she presented to the genetics clinic with a diagnosis of mitochondrial myopathy and underwent whole exome sequencing (WES).ResultsWhole exome sequencing revealed two novel compound heterozygous variants in RYR1 (c.7060_7062del, p.Val2354del and c.4485_4500del, p.Tyr1495X).ConclusionReview of her clinical, pathologic, and genetic findings pointed to a diagnosis of a congenital myopathy with fiber‐type disproportion.
Tailored spiral in‐out spectral‐spatial water suppression pulses for magnetic resonance spectroscopic imaging
Authors: Ma Jun , Wismans Carrie , Cao Zhipeng , Klomp Dennis W. J. , Wijnen Jannie P. , Grissom William A. 
Published: March 2017

PurposeTo develop short water suppression sequences for 7 T magnetic resonance spectroscopic imaging, with mitigation of subject‐specific transmit RF field (
) inhomogeneity.MethodsPatient‐tailored spiral in‐out spectral‐spatial saturation pulses were designed for a three‐pulse WET water suppression sequence. The pulses’ identical spatial subpulses were designed using patient‐specific
maps and a spiral in‐out excitation k‐space trajectory. The subpulse train was weighted by a spectral envelope that was root‐flipped to minimize peak RF demand. The pulses were validated in in vivo experiments that acquired high resolution magnetic resonance spectroscopic imaging data, using a crusher coil for fast lipid suppression. Residual water signals and MR spectra were compared between the proposed tailored sequence and a conventional WET sequence.ResultsReplacing conventional spectrally‐selective pulses with tailored spiral in‐out spectral‐spatial pulses reduced mean water residual from 5.88 to 2.52% (57% improvement). Pulse design time was less then 0.4 s. The pulses’ specific absorption rate were compatible with magnetic resonance spectroscopic imaging TRs under 300 ms, which enabled spectra of fine in plane spatial resolution (5 mm) with good quality to be measured in 7.5 min.ConclusionTailored spiral in‐out spectral‐spatial water suppression enables efficient high resolution magnetic resonance spectroscopic imaging in the brain. Magn Reson Med 79:31–40, 2018. © 2017 International Society for Magnetic Resonance in Medicine.
Slice profile effects on nCPMG SS‐FSE
Authors: Gibbons Eric K. , Le Roux Patrick , Pauly John M. , Kerr Adam B. 
Published: March 2017

PurposeTo determine the effects of the RF refocusing pulse profile on the magnitude of the transverse signal smoothness throughout the echo train in non‐Carr‐Purcell‐Meiboom‐Gill (nCPMG) single‐shot fast spin echo (SS‐FSE) imaging and to design an RF refocusing pulse that provides improved signal stability.Theory and MethodsnCPMG SS‐FSE quadratic phase modulation requires sufficiently high and uniform refocusing flip angle to achieve a stable signal. Typically, refocusing pulses used in SS‐FSE sequences are designed for minimum duration to minimize echo spacing and as a consequence have poor selectivity. However, delay‐insensitive variable rate excitation Shinnar‐Le Roux (DV‐SLR) refocusing pulses can achieve both improved selectivity as well as a short duration. This class of RF pulse is compared against a traditional low time‐bandwidth refocusing pulse in a nCPMG SS‐FSE in simulation, phantom, and in vivo.ResultsDV‐SLR pulses achieve a more stable signal in simulation, phantom, and in vivo cases while maintaining an appropriately short duration as well as not dramatically increasing specific absorption rate (SAR) accumulation.ConclusionThe nCPMG SS‐FSE method demonstrates improved robustness when a more selective refocusing pulse is used. Refocusing pulses that use a time‐varying excitation gradient can achieve this selectivity while maintaining short echo spacing. Magn Reson Med 79:430–438, 2018. © 2017 International Society for Magnetic Resonance in Medicine.
Improving the stability and robustness of incomplete symmetric indefinite factorization preconditioners
Authors: Scott Jennifer , Tůma Miroslav 
Published: March 2017

SummarySparse symmetric indefinite linear systems of equations arise in numerous practical applications. In many situations, an iterative method is the method of choice but a preconditioner is normally required for it to be effective. In this paper, the focus is on a class of incomplete factorization algorithms that can be used to compute preconditioners for symmetric indefinite systems. A limited memory approach is employed that incorporates a number of new ideas with the goal of improving the stability, robustness, and efficiency of the preconditioner. These include the monitoring of stability as the factorization proceeds and the incorporation of pivot modifications when potential instability is observed. Numerical experiments involving test problems arising from a range of real‐world applications demonstrate the effectiveness of our approach.
Wide target analysis of acylglycerols in miso (Japanese fermented soybean paste) by supercritical fluid chromatography coupled with triple quadrupole mass spectrometry and the analysis of the correlation between taste and both acylglycerols and free fatty acids
Authors: Ogawa Takahiro , Izumi Yoshihiro , Kusumoto Kenichi , Fukusaki Eiichiro , Bamba Takeshi 
Published: March 2017

RationaleThe acylglycerols in miso have not been studied although it is known that they are important to the taste. In order to determine the fatty acid constituents in the acylglycerols and analyze them individually, multiple reaction monitoring (MRM) was performed utilizing a single platform, typically using both gas chromatography/mass spectrometry and liquid chromatography/mass spectrometry.MethodsAcylglycerols and fatty acids (FAs) in miso were extracted using the Bligh‐Dyer method. Supercritical fluid chromatography (SFC) with a C30 column was conducted for separation, and mass spectrometric (MS) analysis was performed with electrospray ionization using a triple quadrupole mass spectrometer (QqQMS) in the MRM mode.ResultsThe detection of FAs from the hydrolysis of acylglycerols and individual acylglycerols was achieved using only an SFC/MS platform. From the quality control (QC) sample of miso, we determined the main FA constituents, and then performed wide target analysis using MRM. In total, 23 triacylglycerols, 10 diacylglycerols, two monoacylglycerols, and five FAs were annotated effectively. Furthermore, the important compounds related to taste were determined through the analysis using both the relative quantitative data of acylglycerols and FAs and the quantitative descriptive analysis data of miso.ConclusionsA method for the determination of the FA constituents in acylglycerols after hydrolysis and the comprehensive analysis of acylglycerols and FAs using MRM with SFC/QqQMS was developed. Using the data from the comprehensive analysis of acylglycerols and quantitative descriptive data, the key compounds related to taste were investigated. This type of research on lipids and the taste of food is expected to progress hereafter. Copyright © 2017 John Wiley & Sons, Ltd.
Use of 13C‐ and phosphate 18O‐labeled substrate for studying phosphorus and carbon cycling in soils: a proof of concept
Authors: Gross Avner , Angert Alon 
Published: March 2017

RationaleStable isotope tracers are commonly used to track the transformations of organic carbon (C) and nitrogen (N) in soils but they have not been used to follow coupled cycles of phosphorus (P) and C because P has only one stable isotope.MethodsA novel dually labeled substrate, composed of a 13C‐labeled glucose backbone attached to a phosphate group with known δ18OP value, was used to follow the fate of C and P derived from the same compound. The substrate was amended to soils from two natural oak forests, differing in their P levels, and the δ13C values of respired CO2 and the δ18OP values of soil bioavailable P were measured.ResultsThe δ18OP values of the phosphate accumulated in the soil deviated from the expected value of P that is released from phosphomonoesters by enzymatic reactions (3.7 ‰) and were driven towards isotopic equilibrium with soil water (21.1 ‰), a process which is produced as part of microbial metabolism. This suggests that the substrate's P passed through the microbial biomass before accumulating in the soil, reflecting the rapid microbial turnover rate of the added P. A higher fraction of the substrate‐C was respired in the higher P soil by the end of the incubation (20.3 % in comparison with 9.1 % in the lower P soil), indicating stronger energy limitation in the higher P soils. The higher 13C glucose respiration in the higher P soil also triggered a stronger priming effect than in the lower P soil.ConclusionsOur approach demonstrates that 13C‐ and P‐18O‐dually labeled tracers provide invaluable data on the fate of organic P and C in soils. We encourage biogeochemists and soil scientists to develop similar tracers of this kind. Copyright © 2017 John Wiley & Sons, Ltd.
A class of globally stabilizing feedback controllers for the orbital rendezvous problem
Authors: Leomanni Mirko , Bianchini Gianni , Garulli Andrea , Giannitrapani Antonio 
Published: March 2017

SummaryThe development of feedback control systems for autonomous orbital rendezvous is a key technological challenge for next‐generation space missions. This paper presents a new class of control laws for the orbital rendezvous problem. The controllers belonging to this class are guaranteed to globally asymptotically stabilize the relative dynamics of two satellites in circular or elliptic orbits. The proposed design procedure builds on control techniques for nonlinear systems in cascade form, by exploiting the geometric properties of the orbital element description of the satellite motion. A numerical simulation of a formation flying mission demonstrates the effectiveness of this approach for long‐range and low‐thrust rendezvous operations. Copyright © 2017 John Wiley & Sons, Ltd.