bluuebunny/crossref_metadata_2025 huggingface dataset:
A TDOA Estimation Method Through Phase Difference Square Sums (PDSS)
Authors: Wang Dapeng , Du Hong
Published: August 2019

In order to improve the performance of TDOA estimation under multipath, non-line-of-sight and narrow signal bandwidth conditions, a time difference of arrival (TDOA) estimation method by Phase Difference Square Sum (PDSS) is introduced. Within the baseline time-lags of two separate receivers, PDSS between two received samples of the same signal are calculated for per lag; the TDOA is estimated by searching the minimum of PDSS. Under the condition of different signal-to-noise ratio (SNR) and Sample rates to Signal bandwidth ratio, the estimation error distribution of the PDSS are simulated, and are compared with the generalized cross correlation with phase transform (GCC-PHAT). In multipath propagation and non-line-of-sight environment of the metropolis, the estimation success rates are experimented to evaluate PDSS’s performance relative to GCC_PHAT.
Research on the method of cement bag palletizing system based on machine vision
Authors: Zheng Zujia , Ma Ruyi
Published: August 2019

Aiming at the problem that the traditional cement bag palletizing robot can only accomplish the simple task of handling operation, but can not meet the production requirements, this paper proposes a kind of cement bag palletizing robot based on machine vision, which applies machine vision technology to the traditional cement bag palletizing robot. Firstly, the camera is used to calibrate the visual system of the target, then the image is collected and preprocessed. Finally, the cement bag is recognized according to the SIFT matching algorithm. This method improves the intelligence level of traditional cement bag palletizing robot, makes it have the ability of detection, analysis and decision-making, improves the operation quality of the cement bag palletizing robot, and expands its application scope.
Construction Research of University Data Centre of Cloud Computing Based on Virtualization Technology
Authors: Wang Bei
Published: August 2019

University cloud computing data centre based on virtualization technology can integrate and distribute resources in computing, storage, network, security and other aspects on demand to improve the utilization ratio of resources. This paper analyses the drawbacks of traditional university data centre, gives the design scheme of university cloud computing data centre based on virtualization technology, and draws the architecture diagram of data centre after virtualization. The paper provides the key points of university cloud computing data centre implementation based on virtualization technology. Under high concurrency pressure, we compared the average CPU utilization and TTFB before and after virtualization. The results show that after virtualization, the performance of university data centre has been improved significantly.
Adaptive Q-learning Algorithm for AUV Route Planning
Authors: Zhu Yingying , Dai Changan , Xia Jiahao , Wu Haowei , An Li
Published: August 2019

When applying Q-learning algorithm to AUV route planning, it is difficult to strike a balance between exploration and exploitation. Usually, the fixed greedy rate or the greedy rate with fixed change trend is adopted according to experience. However, the value of greedy rate in the above method cannot be matched with the learning environment, and often occurs a problem of falling into a local optimal solution or slow learning convergence. In order to solve the above problems, we proposed an adaptive Q-learning algorithm. It guides the greedy rate with environmental complexity, and the environmental complexity degree of AUV is evaluated by the environmental complexity mathematical model. By setting up the simulation experiment of two-dimensional environment, the fixed greedy rate and the greedy rate with fixed change trend is compared. The simulation results show that the adaptive Q-learning algorithm considering environmental complexity converges faster and is less prone to fall into local optimal solutions.
Research and Design of an Improved ElGamal Digital Signature Algorithm
Authors: Fang Yi , Cong Linhu , Deng Jianqiu
Published: August 2019

Firstly, the digital signature technology and its basic principle are introduced. Then, an ElGamal digital signature algorithm based on discrete logarithm is described, and two aspects of security and signature efficiency are improved on the basis of this algorithm, and the correctness, security and complexity of the improved scheme are analyzed. The results show that the improved ElGamal algorithm achieves the purpose of improvement.
A semi-supervised clustering algorithm for real network traffic with concept drift
Authors: Hua Qu , Jie Jiang , Jihong Zhao , Yanpeng Zhang
Published: August 2019

Traffic classification has been widely applied for networking. Previous works paid much attention to static network traffic. In this paper, we propose a new strategy for the semi-supervised clustering algorithm to deal the concept drift in a dynamic network, as well as updating the model incrementally. Moreover, our algorithm can find new clusters and reduce the impact of noises. The results of simulation demonstrate the effectiveness of semi-supervised clustering algorithm.
Design of Radionuclides Identification Algorithm Based on Sequence Bayesian Method
Authors: Wu Zeqian , Wang Bairong , Sun Jian
Published: August 2019

An efficient method of radionuclides identification is essential for the work in the nuclear-related area. In this paper, sequential Bayesian method is embedded into a new radionuclides identification algorithm. Through the process of energy screening, parameter estimation, decision-making function updating and judging, the types of radionuclides can be identified quickly and accurately. This algorithm is tested by using the measured energy spectrum detected by LaBr3(Ce) detector, and the results are composed of the following four parts for the case where the widths of region of interest are 4σ and 6σ respectively: the selection experiment of two pre-set parameters of the algorithm; false alarm rate and missed alarm rate of radionuclides identification; the effect of energy drift on the identification accuracy; the average number of total collected particles and valid particles needed for identification process.
Using Conditional Adversarial Networks to Deblur the Sonar Image of the Unknown Motion Blur Kernels
Authors: Yan Zheping , Zhao Hang , Hu Wenyue
Published: August 2019

In order to recover the blurred sonar image collected by the side scan sonar during motion, we propose a solution based on the conditional adversarial networks to deblur the sonar image of the unknown motion blur kernels. First, we use improved conditional adversarial networks to recover the sonar image, and improve the loss function, so that the quality of image generation is improved while the training stability is enhanced. Then we propose a method for generating blurred sonar images. The blurred sonar image generated by this method is closer to the real blurred sonar image. Finally, we made our own sonar image set and trained it with two-timescale update rule. The final results proved that the image restored by this method has higher definition.
The Study of the Merger and Acquisition Behavior under the Perspective of Performance Feedback
Authors: Yin Jingyi
Published: August 2019

Based on the perspective of performance feedback, this paper sets the listed enterprises of the manufacturing industry in Shanghai and Shenzhen A shares from 2012 to 2017 as the study sample. The results of the solid evidence prove that when the enterprise cannot reach the expected performance, the feedback degree of negative performance will increase and the frequency of merger and acquisition would decrease with the increase of the gap between actual and expected performance. When implementing the regime of CEO double dipping as president, the inhibiting effect of the merger and acquisition behavior of negative performance feedback will become weak. On the contrary, when the political correlation intensity is high, the inhibiting effect of the merger and acquisition behavior of negative performance feedback will be enhanced.
The study on robot eviscerating technology and visceral contour recognition based on image processing for poultry
Authors: Chen Yan , Wan Lili
Published: August 2019

In this study, robot eviscerating technology was used in the poultry slaughter industry. The poultry viscera were grabbed by the manipulation with the guidance of machine vision technology. A machine-vision-based method of locating the viscera of poultry carcasses was described. The threshold segmentation method, sobel operator and image operations were used to segment the images of poultry viscera. Subsequently, the visceral contour was extracted and its position was detected for common poultry such as Three-Yellow Chicken. The identification rates of this visceral contour recognition system were 95.3%, suggesting that the proposed image recognition algorithm could achieve the accuracy required for poultry visceral contour detection. Therefore, the traditional artificial poultry eviscerating would be replaced by robot eviscerating technology, and the new technology exhibited higher automation program and better eviscerated effect, the location prediction of viscera and the positioning of the machine vision system could be designed, the new technical means were provided for subsequent research on the conveyor chain of poultry eviscerated.
Research of Machine Learning Algorithm for Broadcasting Spectrum Signal Processing
Authors: Sun Jinyu , Zhou Qun , Shang Jianping , Sun Shuai
Published: August 2019

FM broadcasting is mainly used to transmit sound and other signals in the form of wireless transmission. This thesis is based on a project for a radio department, and mainly focuses on the broadcasting frequency band, uses radio monitoring equipment to scan the spectrum signal of the broadcasting frequency band, and performs the data preprocessing, signal feature extraction and classification processing of the radio frequency spectrum signal on the extracted spectrum signal, so as to extract abnormal signals such as pseudo base stations, black radio, cheats in exams, etc. Firstly, relevant pre-processing is performed on the spectrum information of the broadcast frequency band. Through the improved K-Means algorithm, the original sample data including the glitch signal is eliminated, and the original signal is processed through the wavelet analysis of the spectrum signal. The original signal was decomposed by wavelet and wavelet reconstruction, so as to achieve the purpose of denoising the original signal. Secondly, based on the analysis of signal characteristics and the comparison of a large number of spectrum signals, a method for extracting individual features of spectrum signals is summarized. Finally, the grey relational degree cluster Analysis is used to extract the features of the spectrum signal, which provides a certain basis for the subsequent classification algorithm.
The Influence of Different Saliency on Full-Reference Sonar Image Quality Evaluation
Authors: Zhang Huiqing , Li Shuo , Chen Weiling , Liu Yutao
Published: August 2019

With the advent of sonar technology, our understanding of the ocean has become more comprehensive, especially for deep sea biology and geology. However, the sonar image is easily degraded during the underwater acoustic channel acquisition process, which affects the later research work. To this end, this paper compares and analyzes multiple saliency models and combines them with PSNR, SSIM and GSIM to explore an effective sonar image quality evaluation method. Finally, an experimental analysis on the newly established sonar image quality database shows that the difference of the significance model in predicting human attention has a performance gain effect on the image quality evaluation method when fused with the saliency model.
Reduced-reference image quality assessment method based on wavelet feature extraction and fusion
Authors: Zhang Huiqing , Li Yueqing , Li Shuo , Liu Yutao
Published: August 2019

Virtual reality has many characteristics such as multi-sensation, interactivity, and presence. Virtual reality images, also known as 360-degree panoramic images, provide users with an immersive experience and have been widely used in education, medical, military and many other fields in recent years. 360-degree panoramic images have high resolution and are subject to varying degrees of distortion during transmission and storage. Therefore, the evaluation of virtual reality images has practical significance. To this end, we propose a method for evaluating the quality of images in the new CVIQD database. The proposed image quality assessment model is developed based on Haar wavelet and Db4 wavelet feature extraction and fusion. The method is compared with a single wavelet feature extraction method. Experiments show that the method has better performance.
An Engineering Calculation Method for Regenerative Braking Energy of Metro Vehicles
Authors: Gao Qiang , Tian Xingjun , Tian Mo , Yang Jing , Zhang Jianrui , Lu Ning
Published: August 2019

The feedback-based technical scheme of Metro regenerative braking energy can effectively solve the rapid transfer and comprehensive utilization of regenerative electric energy and can effectively alleviate the reverse impact of regenerative electric energy on traction power supply system. In order to quantify the feedback power capacity and optimize the train dispatching, a simple engineering calculation method of regenerative braking energy is proposed in this paper. Firstly, the basic resistance calculation model is established and the braking characteristics of the vehicles are analysed by using the actual parameters of Metro vehicles. Secondly, the calculation method of regenerative energy is deduced by the energy conversion and balance equation. Finally, the calculation procedure of regenerative braking energy is explicated by an example, and the accuracy of the calculation results is verified.
The role of attentional focus on walking efficiency among older fallers and non-fallers
Authors: Mak Toby C T , Young William R , Lam Wing-Kai , Tse Andy C Y , Wong Thomson W L
Published: August 2019

Background

This study evaluated the effect of attentional focus instructions on movement efficiency during a level-ground walking task in older adults with and without a history of falls.

Methods

One hundred and thirty-four community-dwelling older adults were categorised into older fallers (OF) (n = 37) and older non-fallers (ONF) (n = 97). Each participant was instructed to walk at a self-selected pace along a 6 m walkway under three attentional focus conditions (i.e. internal, goal-directed and control) for a total of nine trials. Average muscle activity indices of lower limb co-contractions were measured using surface electromyography.

Results

Both shank and thigh muscle co-contractions were higher in OF than in ONF in all three conditions. OF also demonstrated higher shank muscle co-contraction under the internal relative to the goal-directed condition, with no such change observed in ONF.

Conclusion

Despite no significant between-group differences in functional balance and balance confidence, relative walking inefficiencies were observed in OF compared with ONF. This finding demonstrates the debilitating consequences of falling that can occur with relative independence from various physiological or psychological factors that are commonly associated with falling and used to rationalise behavioural change. We also provide evidence that OF are more susceptible to conditions that provoke them to allocate attention internally. Therefore, in clinical contexts (e.g. gait rehabilitation), verbal instructions that refer to body movements (internal focus) might serve to compromise movement efficiency in older adults with a history of falls. Such changes will, theoretically, lessen the ability to react efficiently to changing environments experienced in daily life.
Antiphospholipid Antibodies in Patients With Lupus Anticoagulant Prozone Effect
Authors: Murphy Colin H , Jin Jing , Zehnder James L
Published: August 2019

Objectives

Lupus anticoagulant (LAC) is typically associated with thrombosis but also rarely with hemorrhage. Some patients exhibit a prozone effect on LAC testing. Antiphosphatidylserine/prothrombin (aPS/PT) antibodies may provide a mechanism for both hemorrhage and prozone effect. Our goal was to evaluate whether antibody specificities, isotypes, and titers were associated with LAC prozone effect, factor II levels, hemorrhage, and thrombosis.

Methods

Patients with prozone effect noted on LAC testing were entered into a database over 3 years. Factor II activity and aPS/PT antibody testing were performed when a sufficient residual sample was available.

Results

All patients with LAC prozone effect and antibody testing were positive for at least 1 class of aPS/PT antibodies. In addition, aPS/PT IgG titers were significantly associated with thrombosis and significantly inversely associated with factor II levels.

Conclusions

In prozone effect patients, aPS/PT antibodies are associated with LAC prozone effect as well as thrombosis and decreased factor II levels.
U-PASS: unified power analysis and forensics for qualitative traits in genetic association studies
Authors: Gao Zheng , Terhorst Jonathan , Van Hout Cristopher V , Stoev Stilian
Published: August 2019

Despite the availability of existing calculators for statistical power analysis in genetic association studies, there has not been a model-invariant and test-independent tool that allows for both planning of prospective studies and systematic review of reported findings. In this work, we develop a web-based application U-PASS (Unified Power analysis of ASsociation Studies), implementing a unified framework for the analysis of common association tests for binary qualitative traits. The application quantifies the shared asymptotic power limits of the common association tests, and visualizes the fundamental statistical trade-off between risk allele frequency and odds ratio. The application also addresses the applicability of asymptotics-based power calculations in finite samples, and provides guidelines for single-SNP-based association tests. In addition to designing prospective studies, U-PASS enables researchers to retrospectively assess the statistical validity of previously reported associations.

Availability and implementation

U-PASS is an open-source R Shiny application. A live instance is hosted at https://power.stat.lsa.umich.edu. Source is available on https://github.com/Pill-GZ/U-PASS.

Supplementary information

Supplementary data are available at Bioinformatics online.
Variability in the Duration and Thoroughness of Hand Hygiene
Authors: Mumma Joel M , Durso Francis T , Casanova Lisa M , Erukunuakpor Kimberly , Kraft Colleen S , Ray Susan M , Shane Andi L , Walsh Victoria L , Shah Puja Y , Zimring Craig , DuBose Jennifer , Jacob Jesse T
Published: August 2019

We observed 354 hand hygiene instances across 41 healthcare workers doffing personal protective equipment at 4 hospital-based biocontainment units. We measured the duration and thoroughness of each hand hygiene instance. Both parameters varied substantially, with systematic differences between hospitals and differences between healthcare workers accounting for much of the variance.
Factors Associated With Fatality Due to Avian Influenza A(H7N9) Infection in China
Authors: Zheng Shufa , Zou Qianda , Wang Xiaochen , Bao Jiaqi , Yu Fei , Guo Feifei , Liu Peng , Shen Yinzhong , Wang Yimin , Yang Shigui , Wu Wei , Sheng Jifang , Vijaykrishna Dhanasekaran , Gao Hainv , Chen Yu
Published: August 2019

Background

The high case fatality rate of influenza A(H7N9)-infected patients has been a major clinical concern.

Methods

To identify the common causes of death due to H7N9 as well as identify risk factors associated with the high inpatient mortality, we retrospectively collected clinical treatment information from 350 hospitalized human cases of H7N9 virus in mainland China during 2013–2017, of which 109 (31.1%) had died, and systematically analyzed the patients’ clinical characteristics and risk factors for death.

Results

The median age at time of infection was 57 years, whereas the median age at time of death was 61 years, significantly older than those who survived. In contrast to previous studies, we found nosocomial infections comprising Acinetobacter baumannii and Klebsiella most commonly associated with secondary bacterial infections, which was likely due to the high utilization of supportive therapies, including mechanical ventilation (52.6%), extracorporeal membrane oxygenation (14%), continuous renal replacement therapy (19.1%), and artificial liver therapy (9.7%). Age, time from illness onset to antiviral therapy initiation, and secondary bacterial infection were independent risk factors for death. Age >65 years, secondary bacterial infections, and initiation of neuraminidase-inhibitor therapy after 5 days from symptom onset were associated with increased risk of death.

Conclusions

Death among H7N9 virus–infected patients occurred rapidly after hospital admission, especially among older patients, followed by severe hypoxemia and multisystem organ failure. Our results show that early neuraminidase-inhibitor therapy and reduction of secondary bacterial infections can help reduce mortality.

Characterization of 350 hospitalized avian influenza A(H7N9)-infected patients in China shows that age >65 years, secondary bacterial infections, and initiation of neuraminidase-inhibitor therapy after 5 days from symptom onset were associated with increased risk of death.
Gastroenteritis in Men Who Have Sex With Men in Seattle, Washington, 2017–2018
Authors: Newman Kira L , Newman Gretchen Snoeyenbos , Cybulski Robert J , Fang Ferric C
Published: August 2019

Background

Men who have sex with men (MSM) are at risk for sexual transmission of enteric pathogens. The microbiology of gastroenteritis in MSM has not been examined since the advent of antiretroviral therapy and molecular diagnostics. Our objective was to assess the causes of gastroenteritis among MSM living with and without human immunodeficiency virus (HIV) coinfection in Seattle, Washington.

Methods

We conducted a retrospective cohort study of 235 MSM who underwent multiplex stool polymerase chain reaction (PCR) testing between 1 January 2017 and 1 June 2018. We abstracted clinical and laboratory data from electronic medical records. Parallel or reflexive culture and susceptibility testing were performed when PCR detected cultivable pathogens.

Results

Among 235 MSM tested (268 episodes), 131 had 151 episodes with positive test results. 148 (63.0%) individuals were living with HIV. Among positive tests, 88.7% detected a bacterial pathogen, 26% a virus, and 40% a parasite. Diarrheagenic Escherichia coli (enteroaggretative, enteropathogenic), Shigella, and Campylobacter were the most commonly detected bacteria (33.1%, 30.5%, and 17.2% of positive samples, respectively). Forty-three percent of positive specimens had ≥2 pathogens. Etiologies and clinical presentations were similar between men living with and without HIV. Cultured Shigella and Campylobacter isolates were frequently resistant to multiple antibiotics.

Conclusions

MSM present with gastroenteritis from varied pathogens, including some not detected by conventional stool culture. High levels of antibiotic resistance are consistent with frequent antibiotic exposure in this population and the transmission of multiresistant strains. New approaches are needed to detect, treat, and prevent enteric infections in MSM.
Attention Dynamics During Emotion Recognition by Deaf and Hearing Individuals
Authors: Krejtz Izabela , Krejtz Krzysztof , Wisiecka Katarzyna , Abramczyk Marta , Olszanowski Michał , Duchowski Andrew T
Published: August 2019

The enhancement hypothesis suggests that deaf individuals are more vigilant to visual emotional cues than hearing individuals. The present eye-tracking study examined ambient–focal visual attention when encoding affect from dynamically changing emotional facial expressions. Deaf (n = 17) and hearing (n = 17) individuals watched emotional facial expressions that in 10-s animations morphed from a neutral expression to one of happiness, sadness, or anger. The task was to recognize emotion as quickly as possible. Deaf participants tended to be faster than hearing participants in affect recognition, but the groups did not differ in accuracy. In general, happy faces were more accurately and more quickly recognized than faces expressing anger or sadness. Both groups demonstrated longer average fixation duration when recognizing happiness in comparison to anger and sadness. Deaf individuals directed their first fixations less often to the mouth region than the hearing group. During the last stages of emotion recognition, deaf participants exhibited more focal viewing of happy faces than negative faces. This pattern was not observed among hearing individuals. The analysis of visual gaze dynamics, switching between ambient and focal attention, was useful in studying the depth of cognitive processing of emotional information among deaf and hearing individuals.
A scalar radiative transfer model including the coupling between surface and body waves
Authors: Margerin Ludovic , Bajaras Andres , Campillo Michel
Published: August 2019

To describe the energy transport in the seismic coda, we introduce a system of radiative transfer equations for coupled surface and body waves in a scalar approximation. Our model is based on the Helmholtz equation in a half-space geometry with mixed boundary conditions. In this model, Green’s function can be represented as a sum of body waves and surface waves, which mimics the situation on Earth. In a first step, we study the single-scattering problem for point-like objects in the Born approximation. Using the assumption that the phase of body waves is randomized by surface reflection or by interaction with the scatterers, we show that it becomes possible to define, in the usual manner, the cross-sections for surface-to-body and body-to-surface scattering. Adopting the independent scattering approximation, we then define the scattering mean free paths of body and surface waves including the coupling between the two types of waves. Using a phenomenological approach, we then derive a set of coupled transport equations satisfied by the specific energy density of surface and body waves in a medium containing a homogeneous distribution of point scatterers. In our model, the scattering mean free path of body waves is depth dependent as a consequence of the body-to-surface coupling. We demonstrate that an equipartition between surface and body waves is established at long lapse-time, with a ratio which is predicted by usual mode counting arguments. We derive a diffusion approximation from the set of transport equations and show that the diffusivity is both anisotropic and depth dependent. The physical origin of the two properties is discussed. Finally, we present Monte Carlo solutions of the transport equations which illustrate the convergence towards equipartition at long lapse-time as well as the importance of the coupling between surface and body waves in the generation of coda waves.
Advances in mapping population and demographic characteristics at small-area levels
Authors: Fecht Daniela , Cockings Samantha , Hodgson Susan , Piel Frédéric B , Martin David , Waller Lance A
Published: August 2019

Temporally and spatially highly resolved information on population characteristics, including demographic profile (e.g. age and sex), ethnicity and socio-economic status (e.g. income, occupation, education), are essential for observational health studies at the small-area level. Time-relevant population data are critical as denominators for health statistics, analytics and epidemiology, to calculate rates or risks of disease. Demographic and socio-economic characteristics are key determinants of health and important confounders in the relationship between environmental contaminants and health.

In many countries, census data have long been the source of small-area population denominators and confounder information. A strength of the traditional census model has been its careful design and high level of population coverage, allowing high-quality detailed data to be released for small areas periodically, e.g. every 10 years. The timeliness of data, however, becomes a challenge when temporally and spatially highly accurate annual (or even more frequent) data at high spatial resolution are needed, for example, for health surveillance and epidemiological studies. Additionally, the approach to collecting demographic population information is changing in the era of open and big data and may eventually evolve to using combinations of administrative and other data, supplemented by surveys.

We discuss different approaches to address these challenges including (i) the US American Community Survey, a rolling sample of the US population census, (ii) the use of spatial analysis techniques to compile temporally and spatially high-resolution demographic data and (iii) the use of administrative and big data sources as proxies for demographic characteristics.
Safety and Immunogenicity of the Respiratory Syncytial Virus Vaccine RSV/ΔNS2/Δ1313/I1314L in RSV-Seronegative Children
Authors: Karron Ruth A , Luongo Cindy , Mateo Jocelyn San , Wanionek Kimberli , Collins Peter L , Buchholz Ursula J
Published: August 2019

Background

Respiratory syncytial virus (RSV) is the leading global cause of severe pediatric acute respiratory tract illness, and a vaccine is needed. RSV/ΔNS2/Δ1313/I1314L contains 2 attenuating elements: (1) deletion of the interferon antagonist NS2 gene and (2) deletion of codon 1313 of the RSV polymerase gene and the stabilizing missense mutation I1314L. This live vaccine candidate was temperature-sensitive, genetically stable, replication restricted, and immunogenic in nonhuman primates.

Methods

A single intranasal dose of RSV/ΔNS2/Δ1313/I1314L was evaluated in a double-blind, placebo-controlled trial (vaccine-placebo ratio, 2:1) at 106 plaque-forming units (PFU) in 15 RSV-seropositive children and at 105 and 106 PFU in 21 and 30 RSV-seronegative children, respectively.

Results

In RSV-seronegative children, the 105 PFU dose was overattenuated, but the 106 PFU dose was well tolerated, infectious (RSV/ΔNS2/Δ1313/I1314L replication detected in 90% of vaccinees), and immunogenic (geometric mean serum RSV plaque-reduction neutralizing antibody titer, 1:64). After the RSV season, 9 of 20 vaccinees had increases in the RSV titer that were significantly greater than those in 8 of 10 placebo recipients (1:955 vs 1:69, respectively), indicating that the vaccine primed for anamnestic responses after natural RSV exposure.

Conclusion

Rational design yielded a genetically stable candidate RSV vaccine that is attenuated yet immunogenic in RSV-seronegative children, warranting further evaluation.

Clinical Trials Registration

NCT01893554.
How Can We Criticize International Practices?
Authors: Schindler Sebastian , Wille Tobias
Published: August 2019

In this article, we elaborate two distinct ways of criticizing international practices: social critique and pragmatic critique. Our argument is that these two forms of critique are systematically opposed to each other: They are based on opposing epistemic premises, they are motivated by opposing political concerns, and they pursue opposing visions of social progress. Scholars of International Relations (IR) who want to work with the conceptual tools of practice theory are thus confronted with a consequential choice. Understanding the alternatives can help them to be more self-reflexive in their research practices and intervene more forcefully in contemporary political debates. We illustrate these advantages through a discussion of the scholarly debate on the practices of multilateral diplomacy through which the United Nations Security Council authorized a military intervention in Libya in 2011.
Evaluation of in vitro activity of ceftazidime/avibactam and ceftolozane/tazobactam against MDR Pseudomonas aeruginosa isolates from Qatar
Authors: Sid Ahmed Mazen A , Abdel Hadi Hamad , Hassan Abubaker A I , Abu Jarir Sulieman , Al-Maslamani Muna A , Eltai Nahla Omer , Dousa Khalid M , Hujer Andrea M , Sultan Ali A , Soderquist Bo , Bonomo Robert A , Ibrahim Emad Bashir , Jass Jana , Omrani Ali S
Published: August 2019

Objectives

To investigate the in vitro activity of ceftazidime/avibactam and ceftolozane/tazobactam against clinical isolates of MDR Pseudomonas aeruginosa from Qatar, as well as the mechanisms of resistance.

Methods

MDR P. aeruginosa isolated between October 2014 and September 2015 from all public hospitals in Qatar were included. The BD PhoenixTM system was used for identification and initial antimicrobial susceptibility testing, while Liofilchem MIC Test Strips (Liofilchem, Roseto degli Abruzzi, Italy) were used for confirmation of ceftazidime/avibactam and ceftolozane/tazobactam susceptibility. Ten ceftazidime/avibactam- and/or ceftolozane/tazobactam-resistant isolates were randomly selected for WGS.

Results

A total of 205 MDR P. aeruginosa isolates were included. Of these, 141 (68.8%) were susceptible to ceftazidime/avibactam, 129 (62.9%) were susceptible to ceftolozane/tazobactam, 121 (59.0%) were susceptible to both and 56 (27.3%) were susceptible to neither. Twenty (9.8%) isolates were susceptible to ceftazidime/avibactam but not to ceftolozane/tazobactam and only 8 (3.9%) were susceptible to ceftolozane/tazobactam but not to ceftazidime/avibactam. Less than 50% of XDR isolates were susceptible to ceftazidime/avibactam or ceftolozane/tazobactam. The 10 sequenced isolates belonged to six different STs and all produced AmpC and OXA enzymes; 5 (50%) produced ESBL and 4 (40%) produced VIM enzymes.

Conclusions

MDR P. aeruginosa susceptibility rates to ceftazidime/avibactam and ceftolozane/tazobactam were higher than those to all existing antipseudomonal agents, except colistin, but were less than 50% in extremely resistant isolates. Non-susceptibility to ceftazidime/avibactam and ceftolozane/tazobactam was largely due to the production of ESBL and VIM enzymes. Ceftazidime/avibactam and ceftolozane/tazobactam are possible options for some patients with MDR P. aeruginosa in Qatar.
Satellite galaxies in the Illustris-1 simulation: anisotropic locations around relatively isolated hosts
Authors: Brainerd Tereasa G , Yamamoto Masaya
Published: August 2019

We investigate the locations of satellite galaxies in the z = 0 redshift slice of the hydrodynamical Illustris-1 simulation. As expected from previous work, the satellites are distributed anisotropically in the plane of the sky, with a preference for being located near the major axes of their hosts. Due to misalignment of mass and light within the hosts, the degree of anisotropy is considerably less when satellite locations are measured with respect to the hosts’ stellar surface mass density than when they are measured with respect to the hosts’ dark matter surface mass density. When measured with respect to the hosts’ dark matter surface mass density, the mean satellite location depends strongly on host stellar mass and luminosity, with the satellites of the faintest, least massive hosts showing the greatest anisotropy. When measured with respect to the hosts’ stellar surface mass density, the mean satellite location is essentially independent of host stellar mass and luminosity. In addition, the satellite locations are largely insensitive to the amount of stellar mass used to define the hosts’ stellar surface mass density, as long as at least 50–70 per cent of the hosts’ total stellar mass is used. The satellite locations are dependent upon the stellar masses of the satellites, with the most massive satellites having the most anisotropic distributions.
Probing the missing link between the diffuse interstellar bands and the total-to-selective extinction ratio $R_V\,\!-\!$ I. Extinction versus reddening
Authors: Li Kaijun , Li Aigen , Xiang F Y
Published: August 2019

The carriers of the still (mostly) unidentified diffuse interstellar bands (DIBs) have been a long-standing mystery ever since their first discovery exactly 100 yr ago. In recent years, the ubiquitous detection of a large number of DIBs in a wide range of Galactic and extragalactic environments has led to renewed interest in connecting the occurrence and properties of DIBs to the physical and chemical conditions of the interstellar clouds, with particular attention paid to whether the DIB strength is related to the shape of the interstellar extinction curve. To shed light on the nature and origin of the DIB carriers, we investigate the relation between the DIB strength and RV, the total-to-selective extinction ratio, which characterizes how the extinction varies with wavelength (i.e. the shape of the extinction curve). We find that the DIB strength and RV are not related if we represent the strength of a DIB by its reddening-normalized equivalent width (EW), in contrast to the earlier finding of an anticorrelation in which the DIB strength is measured by the extinction-normalized EW. This raises a fundamental question about the appropriate normalization for the DIB EW. We argue that the hydrogen column density is a more appropriate normalization than extinction and reddening.
Non-linear evolution of instabilities between dust and sound waves
Authors: Moseley Eric R , Squire Jonathan , Hopkins Philip F
Published: August 2019

We study the non-linear evolution of the acoustic ‘resonant drag instability’ (RDI) using numerical simulations. The acoustic RDI is excited in a dust–gas mixture when dust grains stream through gas, interacting with sound waves to cause a linear instability. We study this process in a periodic box by accelerating neutral dust with an external driving force. The instability grows as predicted by linear theory, eventually breaking into turbulence and saturating. As in linear theory, the non-linear behaviour is characterized by three regimes – high, intermediate, and low wavenumbers – the boundary between which is determined by the dust–gas coupling strength and the dust-to-gas mass ratio. The high and intermediate wavenumber regimes behave similarly to one another, with large dust-to-gas ratio fluctuations while the gas remains largely incompressible. The saturated state is highly anisotropic: dust is concentrated in filaments, jets, or plumes along the direction of acceleration, with turbulent vortex-like structures rapidly forming and dissipating in the perpendicular directions. The low-wavenumber regime exhibits large fluctuations in gas and dust density, but the dust and gas remain more strongly coupled in coherent ‘fronts’ perpendicular to the acceleration. These behaviours are qualitatively different from those of dust ‘passively’ driven by external hydrodynamic turbulence, with no back-reaction force from dust on to gas. The virulent nature of these instabilities has interesting implications for dust-driven winds in a variety of astrophysical systems, including around cool stars, in dusty torii around active-galactic-nuclei, and in and around giant molecular clouds.
Quasar lenses in the south: searches over the DES public footprint
Authors: Agnello Adriano , Spiniello Chiara
Published: August 2019

We have scanned 5000 deg2 of Southern Sky to search for strongly lensed quasars with five methods, all source oriented, but based on different assumptions and selection criteria. We present a list of high-grade candidates from each method (totalling 98 unique, new candidates), to facilitate follow-up spectroscopic campaigns, including two previously unknown quadruplets, WG 210014.9-445206.4 and WG 021416.37-210535.3. We analyse morphological searches based on Gaia multiplet detection and astrometric offsets, fibre-spectroscopic pre-selection, and X-ray and radio pre-selection. The performance and complementarity of the methods are evaluated on a common sample of known lenses in the Dark Energy Survey public Data Release 1 (DR1) footprint. We recovered in total 13 known lenses, of which 8 are quadruplets. Morphological and colour selection of objects, from the WISE andGaia-DR2 surveys, recovers most of those known lenses, but searches in the radio and X-ray cover regimes that are beyond the completeness of Gaia. Given the footprint, pre-selection, and depth limits, the current number of quads indicates that the union of these searches is complete, and the expected purity on high-grade candidates is ${\approx}60{{\ \rm per\ cent}}$. Ongoing, spectroscopic campaigns confirm this estimate.
Enrichment of the Galactic disc with neutron-capture elements: Mo and Ru
Authors: Mishenina T , Pignatari M , Gorbaneva T , Travaglio C , Côté B , Thielemann F-K , Soubiran C
Published: August 2019

We present new observational data for the heavy elements molybdenum (Mo, Z = 42) and ruthenium (Ru, Z= 44) in F-, G-, and K-stars belonging to different substructures of the Milky Way. The range of metallicity covered is −1.0 < [Fe/H] <  + 0.3. The spectra of Galactic disc stars have a high resolution of 42 000 and 75 000 and signal-to-noise ratio better than 100. Mo and Ru abundances were derived by comparing the observed and synthetic spectra in the region of Mo i lines at 5506, 5533 Å for 209 stars and Ru i lines at 4080, 4584, 4757 Å for 162 stars using the LTE approach. For all the stars, the Mo and Ru abundance determinations are obtained for the first time with an average error of 0.14 dex. This is the first extended sample of stellar observations for Mo and Ru in the Milky Way disc, and together with earlier observations in halo stars it is pivotal in providing a complete picture of the evolution of Mo and Ru across cosmic time-scales.

The Mo and Ru abundances were compared with those of the neutron-capture elements (Sr, Y, Zr, Ba, Sm, Eu). The complex nucleosynthesis history of Mo and Ru is compared with different Galactic Chemical Evolution (GCE) simulations. In general, present theoretical GCE simulations show underproduction of Mo and Ru at all metallicities compared to observations. This highlights a significant contribution of nucleosynthesis processes not yet considered in our simulations. A number of possible scenarios are discussed.
Biases in retrieving planetary signals in the presence of quasi-periodic stellar activity
Authors: Damasso M , Pinamonti M , Scandariato G , Sozzetti A
Published: August 2019

Gaussian process regression is a widespread tool used to mitigate stellar correlated noise in radial velocity (RV) time series. It is particularly useful to search for and determine the properties of signals induced by small-sized low-mass planets (Rp < 4 R⊕, mp < 10 M⊕). By using extensive simulations based on a quasi-periodic representation of the stellar activity component, we investigate the ability in retrieving the planetary parameters in 16 different realistic scenarios. We analyse systems composed by one planet and host stars having different levels of activity, focusing on the challenging case represented by low-mass planets, with Doppler semi-amplitudes in the range 1–3 $\rm{\,m\,s^{-1}}$. We consider many different configurations for the quasi-periodic stellar activity component, as well as different combinations of the observing epochs. We use commonly employed analysis tools to search for and characterize the planetary signals in the data sets. The goal of our injection-recovery statistical analysis is twofold. First, we focus on the problem of planet mass determination. Then, we analyse in a statistical way periodograms obtained with three different algorithms, in order to explore some of their general properties, as the completeness and reliability in retrieving the injected planetary and stellar activity signals with low false alarm probabilities. This work is intended to provide some understanding of the biases introduced in the planet parameters inferred from the analysis of RV time series that contain correlated signals due to stellar activity. It also aims to motivate the use and encourage the improvement of extensive simulations for planning spectroscopic follow-up observations.
The tilt of the local velocity ellipsoid as seen by Gaia
Authors: Everall A , Evans N W , Belokurov V , Schönrich R
Published: August 2019

The Gaia Radial Velocity Spectrometer (RVS) provides a sample of 7224 631 stars with full six-dimensional phase space information. Bayesian distances of these stars are available from the catalogue of Schönrich, McMillan & Eyer. We exploit this to map out the behaviour of the velocity ellipsoid within 5 kpc of the Sun. We find that the tilt of the disc-dominated RVS sample is accurately described by the relation $\alpha = (0.952 \pm 0.007)\arctan (|z|/R)$, where (R, z) are cylindrical polar coordinates. This corresponds to velocity ellipsoids close to spherical alignment (for which the normalizing constant would be unity) and pointing towards the Galactic Centre. Flattening of the tilt of the velocity ellipsoids is enhanced close to the plane and Galactic Centre, whilst at high elevations far from the Galactic Centre the population is consistent with exact spherical alignment. Using the LAMOST catalogue cross-matched with Gaia DR2, we construct thin disc and halo samples of reasonable purity based on metallicity. We find that the tilt of thin disc stars straddles $\alpha = (0.909{\!-\!}1.038)\arctan (|z|/R)$, and of halo stars straddles $\alpha = (0.927{\!-\!}1.063)\arctan (|z|/R)$. We caution against the use of reciprocal parallax for distances in studies of the tilt, as this can lead to serious artefacts.
The subgiant HR 7322 as an asteroseismic benchmark star
Authors: Stokholm Amalie , Nissen Poul Erik , Silva Aguirre Víctor , White Timothy R , Lund Mikkel N , Mosumgaard Jakob Rørsted , Huber Daniel , Jessen-Hansen Jens
Published: August 2019

We present an in-depth analysis of the bright subgiant HR 7322 (KIC 10005473) using Kepler short-cadence photometry, optical interferometry from CHARA, high-resolution spectra from SONG, and stellar modelling using garstec grids, and the Bayesian grid-fitting algorithm basta. HR 7322 is only the second subgiant with high-quality Kepler asteroseismology for which we also have interferometric data. We find a limb-darkened angular diameter of 0.443 ± 0.007 mas, which, combined with a distance derived using the parallax from Gaia DR2 and a bolometric flux, yields a linear radius of 2.00 ± 0.03 R⊙ and an effective temperature of 6350 ± 90 K. HR 7322 exhibits solar-like oscillations, and using the asteroseismic scaling relations and revisions thereof, we find good agreement between asteroseismic and interferometric stellar radius. The level of precision reached by the careful modelling is to a great extent due to the presence of an avoided crossing in the dipole oscillation mode pattern of HR 7322. We find that the standard models predict a stellar radius systematically smaller than the observed interferometric one and that a sub-solar mixing length parameter is needed to achieve a good fit to individual oscillation frequencies, interferometric temperature, and spectroscopic metallicity.