bluuebunny/crossref_metadata_2025 huggingface dataset:
Hyporheic Zone Microbiome Assembly Is Linked to Dynamic Water Mixing Patterns in Snowmelt‐Dominated Headwater Catchments
Authors: Saup C. M. , Bryant S. R. , Nelson A. R. , Harris K. D. , Sawyer A. H. , Christensen J. N. , Tfaily M. M. , Williams K. H. , Wilkins M. J.
Published: October 2019

Terrestrial and aquatic elemental cycles are tightly linked in upland fluvial networks. Biotic and abiotic mineral weathering, microbially mediated degradation of organic matter, and anthropogenic influences all result in the movement of solutes (e.g., carbon, metals, and nutrients) through these catchments, with implications for downstream water quality. Within the river channel, the region of hyporheic mixing represents a hot spot of microbial activity, exerting significant control over solute cycling. To investigate how snowmelt‐driven seasonal changes in river discharge affect microbial community assembly and carbon biogeochemistry, depth‐resolved pore water samples were recovered from multiple locations around a representative meander on the East River near Crested Butte, CO, USA. Vertical temperature sensor arrays were also installed in the streambed to enable seepage flux estimates. Snowmelt‐driven high river discharge led to an expanding zone of vertical hyporheic mixing and introduced dissolved oxygen into the streambed that stimulated aerobic microbial respiration. These physicochemical processes contributed to microbial communities undergoing homogenizing selection, in contrast to other ecosystems where lower permeability may limit the extent of mixing. Conversely, lower river discharge conditions led to a greater influence of upwelling groundwater within the streambed and a decrease in microbial respiration rates. Associated with these processes, microbial communities throughout the streambed exhibited increasing dissimilarity between each other, suggesting that the earlier onset of snowmelt and longer periods of base flow may lead to changes in the composition (and associated function) of streambed microbiomes, with consequent implications for the processing and export of solutes from upland catchments.
Space‐Based Observations for Understanding Changes in the Arctic‐Boreal Zone
Authors: Duncan Bryan N. , Ott Lesley E. , Abshire James B. , Brucker Ludovic , Carroll Mark L. , Carton James , Comiso Josefino C. , Dinnat Emmanuel P. , Forbes Bruce C. , Gonsamo Alemu , Gregg Watson W. , Hall Dorothy K. , Ialongo Iolanda , Jandt Randi , Kahn Ralph A. , Karpechko Alexey , Kawa Stephan R. , Kato Seiji , Kumpula Timo , Kyrölä Erkki , Loboda Tatiana V. , McDonald Kyle C. , Montesano Paul M. , Nassar Ray , Neigh Christopher S.R. , Parkinson Claire L. , Poulter Benjamin , Pulliainen Jouni , Rautiainen Kimmo , Rogers Brendan M. , Rousseaux Cecile S. , Soja Amber J. , Steiner Nicholas , Tamminen Johanna , Taylor Patrick C. , Tzortziou Maria A. , Virta Henrik , Wang James S. , Watts Jennifer D. , Winker David M. , Wu Dong L.
Published: October 2019

Observations taken over the last few decades indicate that dramatic changes are occurring in the Arctic‐Boreal Zone (ABZ), which are having significant impacts on ABZ inhabitants, infrastructure, flora and fauna, and economies. While suitable for detecting overall change, the current capability is inadequate for systematic monitoring and for improving process‐based and large‐scale understanding of the integrated components of the ABZ, which includes the cryosphere, biosphere, hydrosphere, and atmosphere. Such knowledge will lead to improvements in Earth system models, enabling more accurate prediction of future changes and development of informed adaptation and mitigation strategies. In this article, we review the strengths and limitations of current space‐based observational capabilities for several important ABZ components and make recommendations for improving upon these current capabilities. We recommend an interdisciplinary and stepwise approach to develop a comprehensive ABZ Observing Network (ABZ‐ON), beginning with an initial focus on observing networks designed to gain process‐based understanding for individual ABZ components and systems that can then serve as the building blocks for a comprehensive ABZ‐ON.
A New Method for Deriving the Nightside Thermospheric Density Based on GUVI Dayside Limb Observations
Authors: Yu Tingting , Ren Zhipeng , Yu You , Wan Weixing
Published: October 2019

We propose a new method to derive the nightside thermospheric density by extending Global Ultraviolet Imager (GUVI) dayside limb observations using empirical orthogonal function (EOF) analysis. First, we acquire the GUVI dayside total mass density during 2002–2005 to construct a preliminary empirical model (EM). Simultaneously, we decompose the background thermospheric density from U.S. Naval Research Laboratory Mass Spectrometer and Incoherent Scatter Radar Extended model into different EOFs. The decomposed EOFs are then used to fit the continuous density from EM, to develop a new nightside extended model (NEM). The preliminary EM and developed NEM are further evaluated with Challenging Minisatellite Payload (CHAMP) satellite observations. Higher correlation coefficients and smaller relative standard errors between CHAMP observations and the NEM results are obtained than those between CHAMP observations and the EM results, and the NEM results are in good agreement with the CHAMP observations in time series during both daytime and nighttime, which all prove the NEM method is effective to the reproduction and extension of GUVI original dayside observations. Furthermore, the NEM reveals two typical seasonal variation features, the semiannual variation and equinoctial asymmetry of thermospheric density. The model provides an effective tool to derive the nightside thermospheric density and explore the thermospheric intrinsic structure, and needs the further development to achieve more widespread application of the thermosphere.
On Imaging South African Regional Ionosphere Using 4D‐var Technique
Authors: Ssessanga Nicholas , Kim Yong Ha , Habarulema John Bosco , Kwak Young‐Sil
Published: October 2019

One of the major research areas in the space weather community is the ability to understand, characterize, and model a time‐space variant ionosphere through which transionospheric signals propagate. In this paper a strong constraint four‐dimensional variational data assimilation (4D‐var) technique was used to more accurately estimate the South African regional ionosphere (bound latitude 20–35°S, longitude 20–40°E, and altitude 100–1,336 km). The altitude was capped to the JASON‐1 satellite orbital altitude for the purpose of eliminating the plasmasphere contribution hence reducing the computation expense. Background densities were obtained from an empirical internationally recognized ionosphere model (IRI‐2016) and propagated in time using a Gauss‐Markov filter. Ingested data were STECs (slant total electron content) obtained from the South African Global Navigation Satellite System receiver network (TrigNet). The vertically integrated electron content was validated using Global ionosphere Maps and JASON‐3 data over the continent and ocean areas, respectively. Further, vertical profiles after assimilation were compared with data from a network of ground‐based regional ionosondes Hermanus (34.25°S, 19.13°E), Grahamstown (33.3°S, 26.5°E), Louisvale (21.2°S, 28.5°E), and Madimbo (22.4°S, 30.9°E). Results show that assimilation of STEC data has a profound improvement on the estimation of both the horizontal and vertical structures during quiet and storm periods. Accuracy of the horizontal structure decreases from the continent toward the ocean area where GPS receivers are less abundant. Superiority of assimilating STEC is best pronounced during daytime especially when estimating maximum electron density of theF2 layer (NmF2), with a 60% root‐mean‐square error improvement over the background values.
Evapotranspiration Estimation for Tibetan Plateau Headwaters Using Conjoint Terrestrial and Atmospheric Water Balances and Multisource Remote Sensing
Authors: Li Xueying , Long Di , Han Zhongying , Scanlon Bridget R. , Sun Zhangli , Han Pengfei , Hou Aizhong
Published: October 2019

Satellite remote sensing combined with water balance calculations provides a promising approach to estimating evapotranspiration (ET), a critical variable in water‐energy exchange. Here we compare ET estimates from terrestrial and atmospheric water balances, multisource remote sensing (AVHRR, GLEAM, and MOD16), and a land surface model (GLDAS NOAH) for headwaters on the Tibetan Plateau (TP), that is, headwaters of the Brahmaputra (HBR), Salween (HSR), Mekong (HMR), Yangtze (HYR), and Huang (Yellow; HHR) Rivers, for the 2003–2012 period. Results show that (1) ET estimated from terrestrial and atmospheric water balances agrees closely in three basins (HMR, HYR, and HHR) but has large discrepancies in the other two basins (HBR and HSR), mainly caused by uncertainties in the terrestrial water balance; (2) agreement between various ET products and water balance‐derived ET baselines is highest for GLEAM in two basins (HMR and HYR) and GLDAS NOAH in another two basins (HSR and HHR); and (3) large discrepancies between water balance‐derived ET and all ET products are found in the most glacierized HBR, which may reflect the importance of sublimation in the ET process. The decadal mean ET based on water balance‐derived ET baselines is highest in the HHR (447 mm/year) and HSR (430 mm/year) and lowest in the HBR (238 mm/year), ranging from 51% to 78% of mean precipitation in the five TP headwaters. These findings have important implications for ET estimation on the TP headwaters, which greatly influences downstream water availability.
Tannic acid-based nanogel as an efficient anti-inflammatory agent
Authors: Yeo Jiwon , Lee Junseok , Yoon Seonyeong , Kim Won Jong
Published: October 2019

Biologically produced reactive oxygen species (ROS) are important signaling molecules in the human body.
Mechano-responsive fluorescent polydiacetylene-based materials: towards quantification of shearing stress at the nanoscale
Authors: Polacchi Luca , Brosseau Arnaud , Métivier Rémi , Allain Clémence
Published: October 2019

An AFM-induced OFF to ON fluorescence switch: a polydiacetylene derivative shows nanoscale mechano-responsive fluorescence, the intensity of which increases with the applied force.
A new supramolecular binder strongly enhancing the electrochemistry performance for lithium–sulfur batteries
Authors: Zuo Yuan , Liu Ruliang , Zhang Xingcai , Nadimicherla Reddeppa , Huang Junlong , Lu Yuheng , Liu Shaohong , Wu Dingcai , Fu Ruowen
Published: October 2019

We report for the first time a novel supramolecular eutectic liquid (SEL) binder consisting of diphenylamine and benzophenone, which exhibits excellent performance for Li–S batteries.
A novel empirical method for quickly estimating the charge-transfer state of fullerene-donor derivatives
Authors: Liu Xiaolong , Chai Yongqiang , Wu Bo , Liu Liping , Wang Chunru
Published: October 2019

A new convenient equivalent conjugated electron number technique is put forward to predict the charge-transfer state in fullerene-donor derivatives.
Activation of Nrf2 by lead sulfide nanoparticles induces impairment of learning and memory
Authors: Cao Yanhua , Wang Dong , Li Qingzhao , Liu Huajie , Jin Cuihong , Yang Jinghua , Wu Shengwen , Lu Xiaobo , Cai Yuan
Published: October 2019

Lead sulfide nanoparticles (PbS NPs) are semiconductor materials that have been widely applied to light-emitting diodes (LEDs), biological fluorescent probes, infrared detection, solar receivers, ion-selective electrodes, and ion-sensitive materials. However, the effects of PbS NPs on the central nervous system are still unclear. Thus, this study aimed to determine, using rats, the mechanism of action of PbS NPs, exposure to which results in persistent alterations in nervous system function. The results of the Morris water maze test showed that PbS NPs significantly impaired learning and memory. Compared with that in the control group, the lead content in the hippocampal tissue was significantly elevated after PbS NP exposure. Exposure to PbS NPs led to increased oxidative damage in blood and hippocampal tissues, and significantly inhibited the activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) while increasing the serum malondialdehyde (MDA) content. In addition, reactive oxygen species triggered the activation of Nrf2 and the antioxidant system, including HO-1, r-GCS, and GSH-Px. Moreover, we observed significant apoptosis in the hippocampi of the rats using the TUNEL assay and transmission electron microscopy. The MOD values from the TUNEL assay of the hippocampi were all significantly higher than those of the control group, which increased as the concentration of the PbS NPs increased. There were also changes in the ultrastructure of the hippocampal neurons and synapses in the PbS-treated rats, including a shorter synaptic active zone, smaller curvature of the synaptic interface, and thicker postsynaptic density. Therefore, PbS NP exposure could lead to increased brain lead content, oxidative damage, and apoptosis.
Synergistic engineering of architecture and composition in NixCo1−xMoO4@CoMoO4nanobrush arrays towards efficient overall water splitting electrocatalysis
Authors: Li Zekun , Zheng Mingyue , Zhao Xian , Yang Jun , Fan Weiliu
Published: October 2019

Hierarchical NixCo1−xMoO4@CoMoO4nanoarrays that exhibit high activities in the HER, OER and overall water splitting were synthesized by a simple approach.
Electrochemical reduction of N2 to ammonia on Co single atom embedded N-doped porous carbon under ambient conditions
Authors: Liu Yanming , Xu Qi , Fan Xinfei , Quan Xie , Su Yan , Chen Shuo , Yu Hongtao , Cai Zhengjun
Published: October 2019

Co single atom embedded N-doped porous carbon is energy efficient for electrochemical reduction of N2 to NH3 with a high yield.
Efficient thermally activated delayed fluorescence based on carbonitrile-substituted pyridine and carbazole
Authors: Xu Ming , Liu Ming , Shi Ming , Ali Muhammad Umair , Jiao Shibo , Cao Weiran , Wu Yuan-Chun , Meng Hong
Published: October 2019

New thermally activated delayed fluorescence emitters based on carbonitrile-substituted pyridine and carbazole achieved efficient blue and green emission.
Anti‐icing measures in the Italian power system
Authors: Quaia Stefano , Marchesin Alessio , Rampazzo Davide , Mancuso Cristian
Published: October 2019

Despite the good operating results of passive anti‐icing devices installed by the Italian transmission system operator (TSO) on high‐voltage overhead lines (OHLs), the increasing number and consequences of wet snow events have prompted consideration of other anti‐icing measures. In particular, attention focuses on the thermal approach, which is intended to achieve – before, or in the early stage of wet snow events – the anti‐icing current in OHL phase conductors where snow sleeve formation is foreseen. The authors carried out a specific anti‐icing study with reference to a 132 kV critical path in an area of the Apennines, with simulation results illustrated in this study. Anti‐icing measures investigated were (i) load shifting actions and (ii) insertion of shunt reactors used as ballast loads. The results show that shunt reactors are the most effective anti‐icing measure. The main disadvantage of this innovative solution is the degradation of voltage regulation in the area. However, this downside can be limited by combining the insertion of reactors with control of autotransformers under load tap changers. Similar results are obtained from analyses of other critical areas. As a result of these findings, the Italian TSO is now undertaking the installation of the first ballast reactors.
Application of nanoparticles and composite materials for energy generation and storage
Authors: Ibrahim Idowu D. , Jamiru Tamba , Sadiku Emmanuel R. , Hamam Yskandar , Alayli Yasser , Eze Azunna A.
Published: October 2019

Transition to renewable and sustainable energy from fossil fuels (natural gas, coal, and oil) has dominated the research cycle. The shift is as a result of increasing population growth, industrialisation, decreasing oil reserves and hazardous environmental impact of energy generation from fossil fuels. The new methods of energy generation demand functional materials that are smart and strong for generation and storage of energy. Polymeric composite materials have been widely used. With the recent material performance demand, there is a need to improve the properties of the composite. The improvement can be achieved by reinforcing with fibres and/or nanoparticles as the matrix alone does not possess the required properties. The influence of incorporating fibres and/or fillers into the polymeric matrix has been largely reported in many studies. Recent advancement in the development and use of polymeric composites and nanocomposites is discussed for energy applications. The discussion includes material property improvements, processing methods and improving interface adhesion that may arise when compounding the materials. Various areas, in the energy sector where these materials, can be used are equally highlighted.
Boost‐integrated LCL resonant converter with high voltage gain
Authors: Yuan Yisheng , Zhang Zhongyi , Mei Xianglong
Published: October 2019

A boost‐integrated LCL resonant DC–DC converter is proposed, which is constituted by a full‐bridge inverter module, the main transformer and a flyback transformer, resonant unit, and a rectifier module. The primary winding of the flyback transformer is also used as a resonant inductor and a boost inductor to improve the power density and the voltage gain. In order to meet different output environments, the converter can operate in low voltage‐gain mode or high voltage gain mode. In low voltage‐gain mode, the converter operates in PWM with LCL resonance. In high voltage‐gain mode, the converter operates in PWM with boost and LCL resonance, in which boost modulation plays a role before the LCL resonance to increase the output voltage. Compared with the conventional LCL resonant converter, the new converter has higher voltage gain and is more suitable for a wide output range with the same resonant parameters. The operation principles of the proposed converter are clarified. A prototype with 80–140V output and maximum output current 2.9 A is built, and experimental data shows that the maximum efficiency of the prototype can be 94.5%, verifying the correctness of the theoretical analysis.
Low‐cost analogue active gate driver for SiC MOSFET to enable operation in higher parasitic environment
Authors: Krishna Miryala Vamshi , Hatua Kamalesh
Published: October 2019

Operating silicon carbide (SiC) metal–oxide–semiconductor field‐effect transistor (MOSFET) at its rated switching speed may not be always feasible due to excessive voltage and current overshoot and ringing caused by layout parasitic inductance and load parasitic capacitance. This study proposes a low‐cost analogue active gate driver technique for switching SiC MOSFET in the presence of moderate amount of layout parasitic inductance (<200 nH) and load parasitic capacitance (<300 pF). In this study, a based closed‐loop active gate driver circuit is implemented using low‐cost signal level transistors. The present work explains the working of the gate driver during turn‐on and turn‐off switching transients. A detailed design methodology for the gate driver is presented using its high‐frequency model. The proposed active gate driver (AGD) has been verified in hardware platform using a double pulse test setup and in a boost converter test setup. Cree make 1200 V, 36 A SiC MOSFET (C2M0080120D) is used for evaluating the proposed active gate driver. The proposed circuit has sufficient operating bandwidth to drive SiC MOSFET and it is realised with low‐cost transistors.
Enhanced beamspace MUSIC for cost‐effective FMCW automotive radar
Authors: Li Yang , Zhang Cheng , Song Yixin , Huang Yongming
Published: October 2019

As one important sensor for automotive applications, frequency modulated continuous wave (FMCW) radars working at millimetre wave frequency, e.g. 24 or 77 GHz, are drawing much attention in recent years. Compared with range and radial velocity measurement, direction of arrival (DOA) estimation is more challenging in FMCW automotive radars due to the space limitation and computational complexity constraint. The feature of the signal processing procedure further results in the problem of single snapshot and relatively low signal‐to‐noise ratio (SNR) level. In this study, the authors propose a low‐complexity beamspace multiple signal classification (MUSIC) scheme to improve the DOA estimation performance, where (i) the prior information is exploited to improve beamformer design, (ii) a modified MUSIC estimator is formulated to alleviate the performance degradation due to low SNR, (iii) a joint sub‐matrix averaging and Toeplitz structure recovery processing is utilised to compensate the sample covariance estimation error resulted from single snapshot, especially for closely located targets. Simulations are given to demonstrate the efficiency of the authors’ proposed enhanced beamspace DOA estimation for cost‐effective FMCW automotive radar.
Novel confidence level labelling methods for ADS‐B signals with coherent demodulation scheme
Authors: Ren Peng , Wang Jianxin , Xue Wen , Yang Shushu , Song Haiwei
Published: October 2019

In the satellite‐based application, low signal‐to‐noise ratio (SNR) is a considerable obstacle for automatic dependent surveillance‐broadcast (ADS‐B), leading to some erroneous bit declarations. In this case, the confidence level of each bit should be declared legitimately to make full use of error correction. In this study, the authors focus on methods to optimise the confidence declaration for ADS‐B signals with coherent demodulation scheme. A novel optimal‐threshold labelling method is firstly proposed for known and unknown amplitudes. They also present a dynamic‐threshold labelling method, in which a specific threshold is unnecessary. Detailed theoretical analyses are carried out for the proposed methods and are verified by simulations. Finally, they make a comparison between different confidence level labelling methods in terms of reception performance and complexity. A conclusion is set forth that the methods have a high probability of correct reception at low SNRs.
Improved arithmetic for generating Costas arrays using welch construction method
Authors: Wang Shuaixun , Liu Guoman , Han Lin
Published: October 2019

Costas arrays are widely used in radar waveform design, especially for frequency‐coding signal design. Among all the construction methods, exhaustion method requires many calculations, making it time‐consuming to generate Costas arrays with large orders. Many algebraic construction methods for Costas arrays, which require fewer calculations, are developed. Among these methods, Welch construction method is easy to achieve and thus widely used. However, Welch construction method is ineffective for Costas arrays with certain orders on system based on IEEE standard, such as 40 and 42, which should be effective in theory. Through conducting further researches that indicate Welch construction method is ineffective due to the exponential increase of intermediate variables, this study discusses this problem and develops a new arithmetic to solve it.
Tomography of cool giant and supergiant star atmospheres
Authors: Kravchenko K. , Chiavassa A. , Van Eck S. , Jorissen A. , Merle T. , Freytag B. , Plez B.
Published: October 2019

Context. Red supergiants are cool massive stars and are the largest and the most luminous stars in the Universe. They are characterized by irregular or semi-regular photometric variations, the physics of which is not clearly understood.

Aims. The paper aims to derive the velocity field in the red supergiant star μ Cep and to relate it to the photometric variability with the help of the tomographic method.

Methods. The tomographic method allows one to recover the line-of-sight velocity distribution over the stellar disk and within different optical-depth slices. This method was applied to a series of high-resolution spectra of μ Cep, and these results are compared to those obtained from 3D radiative-hydrodynamics CO5BOLD simulations of red supergiants. Fluctuations in the velocity field are compared with photometric and spectroscopic variations, the latter were derived from the TiO band strength and serve, at least partly, as a proxy of the variations in effective temperature.

Results. The tomographic method reveals a phase shift between the velocity and spectroscopic and photometric variations. This phase shift results in a hysteresis loop in the temperature – velocity plane with a timescale of a few hundred days, which is similar to the photometric one. The similarity between the hysteresis loop timescale measured in μ Cep and the timescale of acoustic waves disturbing the convective pattern suggests that such waves play an important role in triggering the hysteresis loops.
Multicenter Study of 342 Anorectal Malformation Patients: Age, Gender, Krickenbeck Subtypes, and Associated Anomalies
Authors: Banu Tahmina , Karim Anwarul , Adel Maryam Ghavami , Lakhoo Kokila , Aziz Tasmiah Tahera , Das Arni , Sharmeen Nugayer , Yapo Benjamin , Ferdous Kazi Md Noor-ul , Kabir Kh Ahasanul , Zahid Mirza Kamrul , Ford Kathryn , Ahsan Md Qumrul , Akter Mastura , Alam Md Afruzul , Hoque Mozammel
Published: October 2019

Introduction Published studies based on Krickenbeck classification of anorectal malformations (ARMs) are still insufficient to assess the global as well as regional relative incidence of different ARM subtypes, gender distribution, and associated anomalies. The primary purpose of this study was to provide an estimate of those in Global Initiative for Children's Surgery (GICS) research group.

Materials and Methods We collected ARM data prospectively for 1 year from four institutes of different geographic locations. A total of 342 patients were included in this study (195, 126, 11, and 10 from Bangladesh, Iran, Papua New Guinea, and Oxford, United Kingdom, respectively).

Results Overall male to female ratio was 1:1. The most frequent ARM subtype was perineal fistula (23.7% = 81/342). About 48.5% (166/342) patients had at least one associated anomaly. Cardiac and genitourinary systems were the most commonly affected systems, 31.6% (108/342) and 18.4% (63/342), respectively. These organ-systems were followed by anomalies of vertebral/spinal (9.9% = 34/342), musculoskeletal (4.4% = 15/342), and gastrointestinal/abdominal (3.2% = 11/342) systems. Rectovesical fistula had the highest percentage (96.4% = 27/28) of associated anomalies. About 18.1% (62/342) patients had multiple anomalies. ARMs (both isolated and with associated anomalies) occurred equally in males and females. Comparison between patients from Bangladesh and Iran showed differences in relative incidence in ARM subtypes. In addition, Iranian patient group had higher percentage of associated anomalies compared with Bangladeshi (73 vs. 35.4%).

Conclusion Our study provides important insights about ARM subtypes, gender distribution and associated anomalies based on Krickenbeck classification especially from Bangladesh and Iran.
Evaluation of the Efficacy of Enoxaparin in the Neonatal Intensive Care Unit
Authors: Song Diane , Magers Jacqueline , Abdel-Rasoul Mahmoud , Prusakov Pavel
Published: October 2019

Objective This article evaluates the efficacy of enoxaparin when targeting anti-factor Xa levels of 0.5 to 1 units per milliliter in the neonatal intensive care unit.

Study Design This is a retrospective chart review of 45 neonates receiving enoxaparin for the treatment of venous thromboembolism. Enoxaparin dosing and corresponding anti-factor Xa levels were collected. Time to resolution of clot was confirmed by imaging and compared between clots in various locations.

Results The median time to clot resolution was 76 days (interquartile range 40–91 days). Clot location, postnatal age, and sex at the clot onset were significantly associated with time to clot resolution in a multivariable Cox model (p-value: 0.03, 0.03, and < 0.01, respectively). Of the 54 patients analyzed for safety, 5 patients (9.3%) experienced bleeding events resulting in the discontinuation of enoxaparin.

Conclusion Based on our findings, 50% of all patients evaluated, regardless of thrombus location, achieved resolution within the first 76 days of therapy. Clots located in the extremities tended to resolve sooner, hence earlier reimaging should be considered.
Pregnancy Outcomes among Hispanics Stratified by Country of Origin
Authors: Mendez-Figueroa Hector , Chauhan Suneet P. , Sangi-Haghpeykar Haleh , Aagaard Kjersti
Published: October 2019

Objective This study aimed to compare the perinatal outcomes among U.S.-born and foreign-born Hispanics and Caucasians and ascertain if length of time in the US was associated with the rate of adverse outcomes.

Study Design Retrospective cohort analysis of gravidae enrolled in our institutional perinatal database. Women delivering a non-anomalous, singleton, at 24 weeks or more and self-identified as Caucasian or Hispanic were included. Women were stratified by country of birth and ethnicity into U.S.-born Caucasian, U.S.-born Hispanic, and U.S. foreign-born Hispanic. Composite maternal (CMM) and neonatal (CNM) morbidity was assessed.

Results Of 20,422 women, 21% were Caucasian, 15% were U.S.-born Hispanics, and 64% were U.S. foreign-born Hispanics. Compared to Caucasians, U.S.-born and foreign-born Hispanic were older, more likely to be a grand multiparous, obese and less likely to be married. Compared to Caucasians, foreign-born Hispanics had a 1.42-fold increased risk of CMM (95% CI 1.26–1.30). Paradoxically, the rate of CNM was 40% lower among neonates born to foreign-born Hispanics (95% CI 0.51–0.74). A significant direct relationship was noted between time in the USA and CMM but not CNM among foreign-born Hispanics.

Conclusion Despite less favorable baseline characteristics, U.S. foreign-born Hispanics have 40% less CNM compared to both Caucasians and U.S.-born Hispanics.
Predatory politics and personalization of power: The abuses and misuses of the National Intelligence and Security Agency (NISA) in Somalia
Authors: Ingiriis Mohamed Haji
Published: October 2019

This article investigates the security sector in Somalia, with a focus on the National Intelligence and Security Agency (NISA), a government security unit, involved in the fight against the Al-Shabaab insurgency. This article argues that the historically traumatic legacy of autocratic oppression of the former military regime gives the Somali intelligence agency an infamous reputation that survives today and plays a significant role in the operations of the intelligence agency. Intelligence agents employ tactics from the late Cold War era military regime’s intelligence services, suggesting striking historical continuities of the military regime in practice and performance. The empirical data also shows that NISA is enmeshed in the ‘dirty war’ between the federal government and Al-Shabaab. Not only does the intelligence agency normalize extrajudicial activities to serve the agenda of political authorities and to suppress their critics, but it also financially benefits from arrests without trials. NISA agents harass the public and political opposition groups daily and brutally suppress mass media and freedom of speech, especially in the government-controlled areas in Mogadishu. As the first empirical academic investigation into NISA, the article contributes to broader debates on intelligence, the anthropology of the state, security studies, and institution- and state-building in violent environments.
The multifaceted nature of impulsivity in Parkinson’s disease
Authors: O’Callaghan Claire
Published: October 2019

This scientific commentary refers to ‘The structural connectivity of discrete networks underlies impulsivity and gambling in Parkinson’s disease’, by Mosley et al. (doi:10.1093/brain/awz327).
High-frequency words in academic spoken English: corpora and learners
Authors: Dang Thi Ngoc Yen
Published: October 2019

EAP teachers and course designers usually assume that learners have already mastered the most frequent words of general language before entering their courses. Therefore, they focus on words that are outside high-frequency vocabulary but common in academic written English. This fixed vocabulary benchmark is questionable given EAP learners’ varied language proficiency. A good understanding of academic spoken English is certainly important for students’ academic success. Concentrating only on academic written vocabulary for comprehending academic spoken English may therefore be problematic. No attempts have been made to address these issues in a single study. This study compared the occurrences of high-frequency words in academic spoken and written English. It also tested EAP learners’ receptive knowledge of these words. Results showed that high-frequency words play a very important part in academic spoken English, but most participants failed to master them receptively. Suggestions for enhancing EAP learners’ knowledge of high-frequency words are provided.
Real-world risk of cardiovascular outcomes associated with hypertriglyceridaemia among individuals with atherosclerotic cardiovascular disease and potential eligibility for emerging therapies
Authors: Lawler Patrick R , Kotrri Gynter , Koh Maria , Goodman Shaun G , Farkouh Michael E , Lee Douglas S , Austin Peter C , Udell Jacob A , Ko Dennis T
Published: October 2019

Aims

Hypertriglyceridaemia in patients with atherosclerotic cardiovascular disease (ASCVD) has been in focus following the REDUCE-IT trial showing benefit with icosapent ethyl. Among individuals with prevalent ASCVD, we sought to quantify the contemporary, real-world risk of ASCVD events associated with hypertriglyceridaemia, as well as estimate icosapent ethyl eligibility and compare trial participants with REDUCE-IT-like individuals in the population.

Methods and results

We examined data from 2 424 865 adults with lipid panels in the Ontario population. Among those with prevalent ASCVD, we examined adjusted associations between triglyceride (TG) and ASCVD events (first occurrence of myocardial infarction, unstable angina, stroke or transient ischaemic attack, coronary revascularization, or cardiovascular death). The proportion of patients with ASCVD potentially eligible for icosapent ethyl was estimated as those with TG 135–499 mg/dL (1.52–5.63 mmol/L) and low-density lipoprotein cholesterol (LDLc) 41–100 mg/dL (1.06–2.59 mmol/L), similar to the lipid cut-offs in REDUCE-IT, and their demographics and event rates examined. Among 196 717 individuals with ASCVD, median age was 69 years and 30% were female. A total of 24 097 composite ASCVD events occurred over a mean (standard deviation) 2.9 (0.5) years of follow-up. Increasing TG was associated with a graded, progressively higher hazard of ASCVD events. Twenty-five percent (49 886) of individuals with ASCVD had hypertriglyceridaemia and controlled LDLc; these patients were demographically similar to those in REDUCE-IT with comparable event rates.

Conclusions

Among patients with ASCVD, hypertriglyceridaemia is common, and is associated with higher ASCVD risk across a range of TG. It is possible that as many as one in four patients with ASCVD may be candidates for emerging therapies.
The role of implantable cardioverter-defibrillators and sudden cardiac death prevention: indications, device selection, and outcome
Authors: Goldenberg Ilan , Huang David T , Nielsen Jens Cosedis
Published: October 2019

Multiple randomized multicentre clinical trials have established the role of the implantable cardioverter-defibrillator (ICD) as the mainstay in the treatment of ventricular tachyarrhythmias and sudden cardiac death (SCD) prevention. These trials have focused mainly on heart failure patients with advanced left ventricular dysfunction and were mostly conducted two decades ago, whereas a more recent trial has provided conflicting results. Therefore, much remains to be determined on how best to balance the identification of patients at high risk of SCD together with who would benefit most from ICD implantation in a contemporary setting. Implantable cardioverter-defibrillators have also evolved from the simple, defibrillation-only devices implanted surgically to more advanced technologies of multi-chamber devices, with physiologic bradycardic pacing, including cardiac resynchronization therapy, atrial and ventricular therapeutic pacing algorithms, and subcutaneous ICDs. These multiple options necessitate individualized approach to device selection and programming. This review will focus on the current knowledge on selection of patients for ICD treatment, device selection and programming, and future directions of implantable device therapy for SCD prevention.
Intraprocedural endpoints to predict durable pulmonary vein isolation: a randomized trial of four post-ablation techniques
Authors: Jiang Ruhong , Chen Minglong , Yang Bing , Liu Qiang , Zhang Zuwen , Zhang Fengxiang , Ju Weizhu , Li Mingfang , Sheng Xia , Sun Yaxun , Zhang Pei , Yu Lu , Chen Shiquan , Zhu Jun , Cheng Hui , Fu Guosheng , Tung Roderick , Jiang Chenyang
Published: October 2019

Aims

The optimal procedural endpoint to achieve permanent pulmonary vein isolation (PVI) during ablation of atrial fibrillation (AF) remains unknown. We aimed to compare the impact of prolonged waiting periods and adenosine triphosphate (ATP) testing after PVI on long-term freedom from AF.

Methods and results

In total, 538 patients (median age 61 years, 62% male) undergoing first-time radiofrequency ablation for paroxysmal AF were randomized into four groups: Group 1 [PVI (no testing), n = 121], Group 2 (PVI + 30min waiting phase, n = 151), Group 3 (PVI+ATP, n = 131), and Group 4 (PVI + 30min+ATP, n = 135). The primary endpoint was freedom from AF. Repeat mapping to assess for late pulmonary vein (PV) reconnection was performed in patients who remained AF-free for >3 years (n = 46) and in those who had repeat ablation for AF recurrence (n = 82). During initial procedure, acute PV reconnection was observed in 33%, 26%, and 42% of patients in Groups 2, 3, and 4, respectively. At 36 months, no significant differences in freedom from AF recurrence were observed among all four groups (55%, 61%, 50%, and 62% for Groups 1, 2, 3, and 4, respectively; P = 0.258). Late PV reconnection was commonly observed, with a similar incidence between patients with and without AF recurrence (74% vs. 83%; P = 0.224).

Conclusion

Although PVI remains the cornerstone for AF ablation, intraprocedural techniques to assess for PV reconnection did not improve long-term success. Patients without AF recurrence after 3 years exhibited similarly high rates of PV reconnection as those that underwent repeat ablation for AF recurrence. The therapeutic mechanisms of AF ablation may not be solely predicated upon durable PVI.
A randomized controlled trial of cardiac resynchronization therapy in patients with prolonged atrioventricular interval: the REAL-CRT pilot study
Authors: Botto Giovanni Luca , Iuliano Assunta , Occhetta Eraldo , Belotti Giuseppina , Russo Giovanni , Campari Monica , Valsecchi Sergio , Stabile Giuseppe
Published: October 2019

Aims

A prolonged PR interval is known to be associated with increased mortality and a higher risk of developing atrial fibrillation (AF). We tested the hypothesis that cardiac resynchronization therapy (CRT) is superior to conventional dual-chamber pacing with algorithms for right ventricular pacing avoidance (DDD-VPA) in preserving systolic and diastolic function and in preventing new-onset AF in patients with normal systolic function, indication for pacing and prolonged atrioventricular conduction (PR interval ≥220 ms).

Methods and results

We randomly assigned 82 patients with ejection fraction >35%, indication for pacing and PR interval ≥220 ms to CRT or to DDD-VPA. On 12-month follow-up examination, the study and control arms did not differ in terms of left ventricular end-systolic volume (44 ± 17 mL vs. 47 ± 16 mL, P = 0.511) or ejection fraction (55 ± 6% vs. 57 ± 8%, P = 0.291). The E to A mitral wave amplitude ratio was higher in the CRT arm (1.3 ± 1.3 vs. 0.8 ± 0.4, P = 0.046) and the E wave deceleration time was longer (262 ± 83 ms vs. 205 ± 51 ms, P = 0.027). Left atrial volume was smaller in the CRT arm (64 ± 17 mL vs. 84 ± 25 mL, P = 0.035). Moreover, the functional class was lower in CRT patients (1.4 ± 0.6 vs. 1.8 ± 0.5, P = 0.010). During follow-up, CRT was associated with a lower risk of new-onset AF [hazard ratio = 0.37 (0.13–0.98), P = 0.046].

Conclusion

Cardiac resynchronization therapy proved superior to DDD-VPA in terms of better diastolic function, less left atrial enlargement and lower risk of new-onset AF, at 12 months. These data need to be confirmed in a larger trial with longer follow-up.

Clinical trial registration

URL: http://clinicaltrials.gov/ Identifier: NCT02150538
Shear wave velocity structure beneath Bandung basin, West Java, Indonesia from ambient noise tomography
Authors: Pranata B , Yudistira T , Widiyantoro S , Brahmantyo B , Cummins P R , Saygin E , Zulfakriza Z , Rosalia S , Cipta A
Published: October 2019

We investigated the seismic shear wave velocity structure of the upper crust beneath the Bandung area in West Java, Indonesia, using ambient seismic noise tomography. We installed 60 seismographs to record ambient seismic noise continuously in the city of Bandung and its surrounding area for 8 months. After inter-station cross-correlation of recordings of ambient seismic noise, we obtained empirical Green's functions for Rayleigh waves. Group velocity dispersion curves for Rayleigh waves between periods of 1 s and 8 s were measured on each inter-station path by applying the multiple filter analysis method with phase-matched processing. The spatial variation of group velocities shows a good correlation with the geological structure of the Bandung Basin. The Rayleigh wave dispersion maps were inverted to obtain the 1D shear wave velocity profiles beneath each station, which were interpolated to infer a pseudo-3D structure under the study region. The results show that the Bandung Basin has a thick layer of sediment. Along the northern, eastern and southern mountains surrounding the Bandung Basin there is high-velocity structure, except to the west of the Tangkuban Parahu volcano, where a massive low-velocity structure extending throughout the upper crust might indicate the presence of fluids or partial melts.
On the measurement of seismic traveltime changes in the time–frequency domain with wavelet cross-spectrum analysis
Authors: Mao Shujuan , Mordret Aurélien , Campillo Michel , Fang Hongjian , van der Hilst Robert D
Published: October 2019

The spatial distribution of temporal variations in seismic wavespeed is key to understanding the sources and physical mechanisms of various geophysical processes. The imaging of wavespeed changes requires accurate measurements of traveltime delays with both high lapse-time and frequency resolutions. However, traditional methods for time-shift estimation suffer from their limited resolutions. In this paper we propose a new approach, the wavelet method, to measure the traveltime changes in the time–frequency domain. This method is based on wavelet cross-spectrum analysis, and can provide optimal time–frequency joint resolution while being computationally efficient. It can deal not only with coda but also dispersive surface waves even in the presence of cycle skipping. Using synthetic coda, we show that the wavelet method can retrieve traveltime shifts more stably and accurately than traditional methods. An application at Salton Sea Geothermal Field indicates that the wavelet method is less affected by spectral smearing and better discriminates dv/v variations at different frequencies. Furthermore, upon investigations on synthetic coda, we illustrate that the bias on dv/v measurements due to changes in source frequency content is likely to be negligible, either with traditional methods or with the new wavelet method. The wavelet method sheds lights on applications of seismic interferometry that aim to locate changes in space.
Comparison of multiple approaches to calculate time-varying biological reference points in climate-linked population-dynamics models
Authors: O’Leary Cecilia A , Thorson James T , Miller Timothy J , Nye Janet A
Published: October 2019

Fisheries managers use biological reference points (BRPs) as targets or limits on fishing and biomass to maintain productive levels of fish stock biomass. There are multiple ways to calculate BRPs when biological parameters are time varying. Using summer flounder (Paralichthys dentatus) as a case study, we investigated time-varying approaches in concert with climate-linked population models to understand the impact of environmentally driven variability in natural mortality, recruitment, and size-at-age on two commonly used BRPs [B0(t) and F35%(t)]. We used the following two approaches to calculate time-varying BRPs: dynamic-BRP and moving-average-BRP. We quantified the variability and uncertainty of different climate dependencies and estimation approaches, attributed BRP variation to variation in life-history processes, and evaluated how using different approaches impacts estimates of stock status. Results indicate that the dynamic-BRP approach using the climate-linked natural mortality model produced the least variable reference points compared to others calculated. Summer flounder stock status depended on the estimation approach and climate model used. These results emphasize that understanding climate dependencies is important for summer flounder reference points and perhaps other species, and careful consideration is warranted when considering what time-varying approach to use, ideally based upon simulation studies within a proposed set of management procedures.