bluuebunny/crossref_metadata_2025 huggingface dataset:
Social media marketing through time‐aware collaborative filtering
Authors: De Maio Carmen , Fenza Giuseppe , Gallo Mariacristina , Loia Vincenzo , Parente Mimmo
Published: March 2017

Social media is assuming a crucial role in purchasing decisions, and most companies are using social media for marketing. Making sense of the unstructured information content shared by users along the time is an emerging challenge. We advise that the dynamic nature with which trends and user's interests evolve along the timeline requires the revising of well‐assessed methods to address, for instance, recommendation provisioning, information retrieval, and so on. Time‐awareness is crucial to more effectively estimate user's interests in the future to better address social media marketing attempting to increase the traction, for instance, posting the right message at the right time. This work defines time‐aware collaborative filtering for estimating users' interest along the time in Twitter. It uses text analysis services to semantically annotate tweets' content and to track concepts considering post frequencies along the time. A model‐based approach implementing K‐Nearest Neighbors is used to estimate user's similarity representing their profile by sampling user's interest with three different techniques: Vectorial Representation, Symbolic Aggregation Approximation, and Median. We show the experimental results comparing these techniques and performing model training in different time windows. The proposed approach is used to address some social media marketing questions.
Coexisting with the dynamic PU, the effect of PU‐returns on a secondary network
Authors: Amini Mohammad Reza , Mahdavi Mehdi , Omidi Mohammad Javad
Published: March 2017

Coexisting with a dynamic primary user network is a challenge in cognitive radio networks, since the rate at which primary user reoccupies the spectrum is high. Therefore, it is important to investigate deeply the effect of primary traffic dynamics on secondary network performance metrics. To do that, interference due to both sensing error and primary user re‐occupancy must be formulated and considered in throughput and collision probability. Besides them, secondary packet retransmissions due to such interference should be considered in metrics such as average energy consumption and average packet delay. In this study, we formulate the mentioned secondary network metrics regarding to such kinds of interference and secondary packet retransmission. Numerical results along with discussions are given to clarify derived expressions. Simulations are also performed to justify the theoretical results, and optimum operating point for secondary network settings is derived by genetic algorithm.
Exploring the impact of multidecadal environmental changes on the population genetic structure of a marine primary producer
Authors: Lundholm Nina , Ribeiro Sofia , Godhe Anna , Rostgaard Nielsen Lene , Ellegaard Marianne
Published: March 2017

Many marine protists form resting stages that can remain viable in coastal sediments for several decades. Their long‐term survival offers the possibility to explore the impact of changes in environmental conditions on population dynamics over multidecadal time scales. Resting stages of the phototrophic dinoflagellate Pentapharsodinium dalei were isolated and germinated from five layers in dated sediment cores from Koljö fjord, Sweden, spanning ca. 1910–2006. This fjord has, during the last century, experienced environmental fluctuations linked to hydrographic variability mainly driven by the North Atlantic Oscillation. Population genetic analyses based on six microsatellite markers revealed high genetic diversity and suggested that samples belonged to two clusters of subpopulations that have persisted for nearly a century. We observed subpopulation shifts coinciding with changes in hydrographic conditions. The large degree of genetic diversity and the potential for both fluctuation and recovery over longer time scales documented here, may help to explain the long‐term success of aquatic protists that form resting stages.
Egg limitation and individual variation in parasitization risk among hosts in host–parasitoid dynamics
Authors: Okuyama Toshinori
Published: March 2017

Egg limitation is known to destabilize host–parasitoid dynamics. This study reexamines the effect of egg limitation in light of the individual variation in parasitization risk among hosts (e.g., some hosts are more likely to be parasitized than others). Previous studies have considered egg limitation (predicted as a destabilizing factor) and individual variation among hosts (predicted as a stabilizing factor) in isolation; however, their interaction is not known. An individual‐based model was used to examine the effects of each factor and their interaction. The model‐based analysis shows a clear interaction between egg limitation and individual variation in risk among hosts. Egg limitation can both stabilize and destabilize host–parasitioid dynamics depending on the presence and absence of the risk variation. The result suggests that the population‐dynamic consequences of egg limitation are more complex than previously thought and emphasizes the importance of the simultaneous consideration of multiple ecological factors (with individual‐level details) to uncover potential interactions among them.
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

Given 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.
Probabilistic peak detection in CE‐LIF for STR DNA typing
Authors: Woldegebriel Michael , van Asten Arian , Kloosterman Ate , Vivó‐Truyols Gabriel
Published: March 2017

In this work, we present a novel probabilistic peak detection algorithm based on a Bayesian framework for forensic DNA analysis. The proposed method aims at an exhaustive use of raw electropherogram data from a laser‐induced fluorescence multi‐CE system. As the raw data are informative up to a single data point, the conventional threshold‐based approaches discard relevant forensic information early in the data analysis pipeline. Our proposed method assigns a posterior probability reflecting the data point's relevance with respect to peak detection criteria. Peaks of low intensity generated from a truly existing allele can thus constitute evidential value instead of fully discarding them and contemplating a potential allele drop‐out. This way of working utilizes the information available within each individual data point and thus avoids making early (binary) decisions on the data analysis that can lead to error propagation. The proposed method was tested and compared to the application of a set threshold as is current practice in forensic STR DNA profiling. The new method was found to yield a significant improvement in the number of alleles identified, regardless of the peak heights and deviation from Gaussian shape.
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

This 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

Objectives

Although 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.

Methods

As 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.

Results

Carers' 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.

Conclusions

The 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.
Cholinergic and dopaminergic neuronal differentiation of human adipose tissue derived mesenchymal stem cells
Authors: Marei Hany El Sayed , El‐Gamal Aya , Althani Asma , Afifi Nahla , Abd‐Elmaksoud Ahmed , Farag Amany , Cenciarelli Carlo , Thomas Caceci , Anwarul Hasan
Published: March 2017

Mesenchymal stem cells (MSCs) are multipotent cells that can differentiate into various cell types such as cartilage, bone, and fat cells. Recent studies have shown that induction of MSCs in vitro by growth factors including epidermal growth factor (EGF) and fibroblast growth factor (FGF2) causes them to differentiate into neural like cells. These cultures also express ChAT, a cholinergic marker; and TH, a dopaminergic marker for neural cells. To establish a protocol with maximum differentiation potential, we examined MSCs under three experimental culture conditions using neural induction media containing FGF2, EGF, BMP‐9, retinoic acid, and heparin. Adipose‐derived MSCs were extracted and expanded in vitro for 3 passages after reaching >80% confluency, for a total duration of 9 days. Cells were then characterized by flow cytometry for CD markers as CD44 positive and CD45 negative. MSCs were then treated with neural induction media and were characterized by morphological changes and Q‐PCR. Differentiated MSCs expressed markers for immature and mature neurons; β Tubulin III (TUBB3) and MAP2, respectively, showing the neural potential of these cells to differentiate into functional neurons. Improved protocols for MSCs induction will facilitate and ensure the reproducibility and standard production of MSCs for therapeutic applications in neurodegenerative diseases.
Sphingolipids metabolism in the salivary glands of rats with obesity and streptozotocin induced diabetes
Authors: Garbowska Marta , Łukaszuk Bartłomiej , Mikłosz Agnieszka , Wróblewski Igor , Kurek Krzysztof , Ostrowska Lucyna , Chabowski Adrian , Żendzian‐Piotrowska Małgorzata , Zalewska Anna
Published: March 2017

Diabetes is considered a major public health problem affecting millions of individuals worldwide. Remarkably, scientific reports regarding salivary glands sphingolipid metabolism in diabetes are virtually non‐existent. This is odd given the well‐established link between the both in other tissues (e.g., skeletal muscles, liver) and the key role of these glands in oral health preservation. The aim of this paper is to examine sphingolipids metabolism in the salivary glands in (pre)diabetes (evoked by high fat diet feeding or streptozotocin). Wistar rats were allocated into three groups: control, HFD‐, or STZ‐diabetes. The content of major sphingolipid classes in the parotid (PSG) and submandibular (SMSG) glands was assessed via chromatography. Additionally, Western blot analyses were employed for the evaluation of key sphingolipid signaling pathway enzyme levels. No changes in ceramide content in the PSG were found, whereas an increase in ceramide concentration for SMSG of the STZ group was observed. This was accompanied by an elevation in SPT1 level. Probably also sphingomyelin hydrolysis was increased in the SMSG of the STZ‐diabetic rats, since we observed a significant drop in the amount of SM. PSG and SMSG respond differently to (pre)diabetes, with clearer pattern presented by the later gland. An activation of sphingomyelin signaling pathway was observed in the course of STZ‐diabetes, that is, metabolic condition with rapid onset/progression. Whereas, chronic HFD lead to an inhibition of sphingomyelin signaling pathway in the salivary glands (manifested in an inhibition of ceramide de novo synthesis and accumulation of S1P).
Screening for potential susceptibility to rubella in an antenatal population: A multivariate analysis
Authors: Snell Luke Blagdon , Smith Colette , Chaytor Shelley , McRae Kathryn , Patel Mauli , Griffiths Paul
Published: March 2017

Rubella causes disease in the fetus. Immunity to rubella is therefore, routinely screened in pregnant women. In this retrospective observational study, we assessed the levels of potential susceptibility to rubella in the population of a north London antenatal clinic. Risk factors for potential susceptibility to rubella and changes in potential susceptibility to rubella over time were studied. Almost all women were screened for potential susceptibility to rubella (99.8%). The majority were predicted to be immune (96.8%). Women booking in later years within the study period showed higher levels of potential susceptibility to rubella. Booking during each subsequent year in the study gave women an odds ratio of 0.91 (CI:0.84, 0.98, P = 0.009) of being predicted to have immunity against rubella. Age was associated with predicted immunity to rubella, with a 5.1% (CI:3.3%, 6.9%, P < 0.001) increased likelihood for every year older. Previous pregnancy was predictive of immunity against rubella with an odds ratio of 1.41 (CI 1.21, 1.61, P = 0.001). Those from a non‐white ethnicity were less likely to have antibodies predictive of immunity (OR: 0.730, CI: 0.581, 0.879 P < 0.001). Country of birth was associated with differences in potential susceptibility, with those being born outside of the British Isles having an odds ratio for predicted immunity of 0.63 (CI:0.35,0.91, P = 0.001). Being born in a high‐risk country for rubella non‐immunity was also a risk factor, giving an odds ratio of predicted immunity to rubella of 0.55 (CI:0.32, 0.77, P < 0.001).
Astrocytic Vesicle‐based Exocytosis in Cultures and Acutely Isolated Hippocampal Rodent Slices
Authors: Jorgačevski Jernej , Potokar Maja , Kreft Marko , Guček Alenka , Mothet Jean‐Pierre , Zorec Robert
Published: March 2017

Astrocytes are excitable neural cells that contribute to brain information processing via bidirectional communication with neurons. This involves the release of gliosignaling molecules that affect synapses patterning and activity. Mechanisms mediating the release of these molecules likely consist of non‐vesicular and vesicular‐based mechanisms. It is the vesicle‐based regulated exocytosis that is an evolutionary more complex process. It is well established that the release of gliosignaling molecules has profound effects on information processing in different brain regions (e.g., hippocampal astrocytes contribute to long‐term potentiation [LTP]), which has traditionally been considered as one of the cellular mechanisms underlying learning and memory. However, the paradigm of vesicle‐based regulated release of gliosignaling molecules from astrocytes is still far from being unanimously accepted. One of the most important questions is to what extent can the conclusions obtained from cultured astrocytes be translated to in vivo conditions. Here, we overview the properties of vesicle mobility and their fusion with the plasma membrane in cultured astrocytes and compare these parameters to those recorded in astrocytes from acute brain hippocampal slices. The results from both experimental models are similar, which validates experiments on isolated astrocytes and further supports arguments in favor of in vivo vesicle‐based exocytotic release of gliosignaling molecules. © 2017 Wiley Periodicals, Inc.
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

This 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

Recent 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

The 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

Background

Pathogenic 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.

Methods

We 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).

Results

Whole exome sequencing revealed two novel compound heterozygous variants in RYR1 (c.7060_7062del, p.Val2354del and c.4485_4500del, p.Tyr1495X).

Conclusion

Review 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

Purpose

To develop short water suppression sequences for 7 T magnetic resonance spectroscopic imaging, with mitigation of subject‐specific transmit RF field (
) inhomogeneity.

Methods

Patient‐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.

Results

Replacing 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.

Conclusion

Tailored 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

Purpose

To 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 Methods

nCPMG 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.

Results

DV‐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.

Conclusion

The 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

Sparse 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.
Convergence order estimates of the local discontinuous Galerkin method for instationary Darcy flow
Authors: Rupp Andreas , Knabner Peter
Published: March 2017

We present a new a priori stability and convergence analysis for the local discontinuous Galerkin method applied to the instationary Darcy problem formulated on a d‐dimensional polytope with nonhomogeneous Neumann and Dirichlet boundary conditions. In addition to including a spatially and temporally varying permeability tensor into all estimates, the utilized analysis technique produces a convergence order result for the primary and the flux variables. The only stabilization in the proposed scheme is represented by a penalty term in the primary unknown, and our analysis provides some insights into the role played by this particular choice of stabilization. © 2016 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 33: 1374–1394, 2017
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

Rationale

The 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.

Methods

Acylglycerols 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.

Results

The 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.

Conclusions

A 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

Rationale

Stable 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.

Methods

A 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.

Results

The 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.

Conclusions

Our 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

The 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.
Integrated Design of MnO2@Carbon Hollow Nanoboxes to Synergistically Encapsulate Polysulfides for Empowering Lithium Sulfur Batteries
Authors: Rehman Sarish , Tang Tianyu , Ali Zeeshan , Huang Xiaoxiao , Hou Yanglong
Published: March 2017

Lithium sulfur batteries (LSBs) with high theoretical energy density are being pursued as highly promising next‐generation large‐scale energy storage devices. However, its launch into practical application is still shackled by various challenges. A rational nanostructure of hollow carbon nanoboxes filled with birnessite‐type manganese oxide nanosheets (MnO2@HCB) as a new class of molecularly‐designed physical and chemical trap for lithium polysulfides (Li2Sx (x = 4–8)) is reported. The bifunctional, integrated, hybrid nanoboxes overcome the obstacles of low sulfur loading, poor conductivity, and redox shuttle of LSBs via effective physical confinement and chemical interaction. Benefiting from the synergistic encapsulation, the developed MnO2@HCB/S hybrid nanoboxes with 67.9 wt% sulfur content deliver high specific capacity of 1042 mAh g−1 at the current density of 1 A g−1 with excellent Coulombic efficiency ≈100%, and retain improved reversible capacity during long term cycling at higher current densities. The developed strategy paves a new path for employing other metal oxides with unique architectures to boost the performance of LSBs.
Mid‐trimester sonographic cervical consistency index to predict spontaneous preterm birth in a low‐risk population
Authors: Baños N. , Murillo‐Bravo C. , Julià C. , Migliorelli F. , Perez‐Moreno A. , Ríos J. , Gratacós E. , Valentin L. , Palacio M.
Published: March 2017

Objectives

To investigate the effectiveness of mid‐trimester sonographic cervical consistency index (CCI) for the prediction of spontaneous preterm birth (sPTB) in low‐risk pregnancies and to compare its performance with that of mid‐trimester sonographic cervical‐length (CL) measurement.

Methods

This was a prospective cohort study of women with a singleton pregnancy examined by ultrasound at 19 + 0 to 24 + 6 weeks' gestation. All women underwent transvaginal ultrasound examination of the cervix, but CCI and CL were measured, offline, only in women without a risk factor for sPTB. Staff and participants were blinded to CL and CCI results. CCI was obtained by calculating the ratio between the anteroposterior diameter of the uterine cervix at maximum compression and at rest. The primary outcome was prediction of sPTB before 37 + 0 weeks. Receiver–operating characteristics (ROC) curves were produced and sensitivity and specificity were calculated for the optimal cut‐off based on the ROC curve and for the 1st, 5th and 10th centiles of CCI and CL. Intraclass correlation coefficients (ICC) and Bland–Altman plots were used to estimate intra‐ and interobserver agreement and reliability for measurement of CCI and CL.

Results

Of the 749 women who underwent ultrasound examination of the cervix, 532 were included for analysis. The rates of sPTB before 37 + 0 and before 34 + 0 weeks were 4.1% (22/532) and 1.3% (7/532), respectively. The rates of short cervix < 25 mm and ≤ 20 mm were 0.9% (5/532) and 0.4% (2/532), respectively. The area under the ROC curve (AUC) with regard to predicting sPTB before 37 + 0 weeks was 0.84 (95% CI, 0.75–0.93) for CCI compared with 0.68 (95% CI, 0.56–0.81) for CL (P = 0.03). The optimal cut‐off based on the ROC curve was 64.6% for CCI (sensitivity, 77.3%; specificity, 82.7%) and that for CL was 37.9 mm (sensitivity, 72.7%; specificity, 61.2%). The AUC with regard to predicting sPTB before 34 + 0 weeks was 0.87 (95% CI, 0.71–1.0) for CCI compared with 0.71 (95% CI, 0.47–0.94) for CL (P = 0.25). The optimal cut‐off based on the ROC curve was 63.6% for CCI (sensitivity, 85.7%; specificity, 84.0%) and that for CL was 37.9 mm (sensitivity, 85.7%; specificity, 61.3%). Intraobserver ICC was > 0.90 both for CCI and CL, while interobserver ICC was 0.89 for CCI and 0.90 for CL.

Conclusions

Second‐trimester CCI is a better predictor of sPTB < 37 weeks in low‐risk pregnancies than is CL. External validation is needed as well as studies assessing the value of CCI as a screening tool in unselected and high‐risk populations. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.
The terrestrial hydrologic cycle: an historical sense of balance
Authors: Duffy Christopher J
Published: March 2017

In this article, I explore the evolving historical views of the terrestrial hydrologic cycle through a lens that might be called ‘a model of balance.’ The notion of balance in western literature, seems to me to capture a central theme for how scholars of natural history, medieval mathematicians, designers of scientific instruments, and early waterworks engineers viewed the complexities and evaluated the evidence for how water moves in the terrestrial landscape. Using historical images and text, this study attempts to document how we arrived at the modern interpretation, its sources, origins, and relationships within the terrestrial earth. By comparing ancient models for the hydrologic cycle one can begin to construct a plausible story of its evolution as well as the important actors. I pay particular attention to the origins and sources of springs, rivers, and groundwater, the kinds of evidence proposed, and its relation to the sense of balance that emerges. Finally, I argue that at by the end of the 18th and into the early 19th century, the modern view of the terrestrial hydrologic cycle that emerged became a necessary foundation for the geophysical, ecological, and cultural Earth science themes that still flourish today. WIREs Water 2017, 4:e1216. doi: 10.1002/wat2.1216

This article is categorized under:

Science of Water > Hydrological Processes

Human Water > Water as Imagined and Represented
Surface roughness measurements in NFMQL assisted turning of titanium alloys: An optimization approach
Authors: Gupta Munish K. , Sood P. K.
Published: March 2017

The prediction and optimization of surface roughness values remain a critical concern in nano-fluids based minimum quantity lubrication (NFMQL) turning of titanium (grade-2) alloys. Here, we discuss an application of response surface methodology with Box–Cox transformation to determine the optimal cutting parameters for three surface roughness values, i.e., Ra, Rq, and Rz, in turning of titanium alloy under the NFMQL condition. The surface roughness prediction model has been established based on the selected input parameters such as cutting speed, feed rate, approach angle, and different nano-fluids used. Then the multiple regression technique is used to find the relationship between the given responses and input parameter. Further, the experimental data were optimized through the desirability function approach. The findings from the current investigation showed that feed rate is the most effective parameter followed by cutting speed, different nano-fluids, and approach angle on Ra and Rq values, whereas cutting speed is more effective in the case of Rz under NFMQL conditions. Moreover, the predicted results are comparatively near to the experimental values and hence, the established models of RSM using Box-Cox transformation can be used for prediction satisfactorily.
Effects of nicorandil on renal function and histopathology in rats with partial unilateral ureteral obstruction
Authors: Ozturk Hayrettin , Firat Tulin , Tekce Buket Kin , Yilmaz Fahri , Ozturk Hulya
Published: March 2017

To evaluate the effects of nicorandil in a rat kidney model of partial unilateral ureteral obstruction (PUUO). Thirty male rats were randomly divided into three groups as follows: (1) Group 1 (Sham‐control), ureters of the rats were manipulated but not ligated; (2) Group 2 (PUUO‐untreated), PUUO was performed with two‐thirds of the left ureter embedded in the psoas muscle; and (3) Group 3 (PUUO‐nicorandil treated). After PUUO was established, nicorandil (15 mg/kg/day) was administered by gastric lavage for 21 days to determine its effects on PUUO‐induced histopathological‐, functional‐, and oxidative stress‐induced changes. The serum levels of blood urea nitrogen and creatinine were reduced in Group 3. The level of urinary albumin and the ratio of urinary protein/creatinine were increased in the kidneys of Group 2 but decreased in Group 3. Malondialdehyde value was decreased in Group 3 compared with Group 2. Antioxidant enzyme activities (catalase, superoxide dismutase, and glutathione peroxidase) were decreased in Group 2. Nicorandil treatment caused an increase in these enzyme activities. In Group 3, leukocyte infiltration and tubular dilatation were significantly reduced. Other parameters, such as degeneration of tubular epithelium and fibrosis, also showed a marked improvement in Group 3. Expression of inducible nitric oxide synthase in Group 2 and expression of endothelial nitric oxide synthase in Group 3 were significantly elevated. Nicorandil can inhibit renal tubular damage and tubulointerstitial fibrosis by reducing the effects of oxidative stress after PUUO.
Among the Romantics: E. P. Thompson and the Poetics of Disenchantment
Authors: Epstein James
Published: March 2017

This article examines key themes in the political and intellectual life of E. P. Thompson. It argues for the centrality of romanticism to his work; it focuses on his unfinished study of the early Romantics. Thompson drew parallels between socialist hopes and disappointments of his own day and the reactions of the early romantic poets to the failed promise of the French Revolution. This article charts the trajectory of the early Romantics as they moved from political engagement to retreat, and relates this trajectory to Thompson's own politics. Thompson discerned a pattern whereby intellectuals and artists moved through stages from political engagement to disenchantment and then to “apostasy” or default. Disenchantment could be a productive condition; at issue was how the poet handled the “authenticity of experience,” how disenchantment was dealt with in verse. Both Thompson and the Romantics privileged the concept of “experience” which they set in opposition to abstract theory. The article's final section turns to themes that Thompson had intended to address but left unfinished, including shifting views of patriotism and the defeated cause of women's rights. For Thompson the romantic impulse was ultimately linked to utopian desire, to the capacity to imagine that which is “not yet.”