bluuebunny/crossref_metadata_2025 huggingface dataset:
Simulation analysis of the seismic performance of electrical equipment by redundant length of flexible conductors in interconnected circuits
Authors: Liu Zhenlin , Sun Yuhan , Gao Po
Published: November 2020

The interconnection circuit of composite pillar insulators with five different redundant lengths of flexible conductors is established, and the simulation analysis of seismic effects is carried out to study the effect of flexible conductors on the seismic performance of electrical equipment when they are used in the interconnection circuit of electrical equipment. Numerical simulation results are used to analyze the changes in the stress and displacement response of pillar insulators when the redundant length of flexible conductors is varied, and the seismic response law of electrical equipment in the interconnection circuit connected by flexible conductors is obtained, which provides a reference for the seismic design of electrical equipment circuit.
Optimization Design of Track Control Algorithm Based on Convolutional Neural Network
Authors: Luo Nanhang , Zhao Kunming , Du Enwu , Li Yongquan
Published: November 2020

At present, the track control of unmanned surface vessel (USV) is mainly divided into direct track control and indirect track control, both of which have their advantages in the aspect of USV track control. Though having high control precision, the former still fails to meet the related requirements. To tackle this problem, the nonlinear model predictive control (NMPC) algorithm was optimized based on the convolutional neural network (CNN) in order to design a direct USV track controller. In consideration of the nonlinearity and time lag problems that are likely to occur in USV track control, the convolutional neural network was used to solve the optimal control sequence of the predictive control algorithm. The simulation test indicates that this algorithm has effectively improved the accuracy and real-time performance of track control.
Study on Transient Wind Field Model of Transmission Line Based on Multivariable Harmonic Superposition Method
Authors: Li Mu , Xiang Tao , Wang Yiping , Chen Kun
Published: November 2020

The wind deflection angle is directly related to the electric gap and the construction cost of the transmission line, so the accuracy of the wind deflection calculation method and the reasonable value of the relevant parameters are very important for the safe operation and economic rationality of the transmission line. Because of not considering the effect of wind speed fluctuation and thunderstorm impact wind and other adverse weather conditions, the calculation of wind deviation is often unsafe. In this paper, the multi variable harmonic superposition method is used to establish the transient wind field model under strong wind and thunderstorm blast weather conditions, considering the temporal and spatial correlation characteristics of wind field. On this basis, the distribution model of fluctuating wind load acting on the transmission line is constructed, which provides the basis for the subsequent wind deflection calculation of transmission line.
Voltage Stability Analysis of Synchronized Current Phasor Control Based on Bifurcation Theory
Authors: Wang Wei , Shi Qianhong , Zhu Guofang , Wang Zhijun , Ding Lei
Published: November 2020

Synchronized Current Phasor Control (SCPC) is a novel inverter control method proposed recently. This paper investigates the voltage stability of a simple SCPC grid based on the bifurcation theory. Firstly, the expression of the bifurcation point of the simple SCPC grid is derived, and then the variation of voltage stability domain is analysed according to the trajectory of bifurcation point when the inverter droop parameters change. The theoretical analysis results show that the droop parameters have an obvious influence on the voltage stability, which provides guidance for parameter setting.
Analysis of Current Carrying Capacity of Power Cable Based on DTS
Authors: Yaodong Zhang , Yi Kan , Xiaopo Mao , Xueming Zhou , Zhiqiang Feng , Zeqi Huang , Xiang Ren , Tianru Shi , Jianjin Fu , Junjie Huang
Published: November 2020

This article uses a distributed optical fiber temperature measurement system (DTS, Distributed Temperature Sensing) to fix the temperature measurement optical fiber on the surface of the power cable, collect the real-time operating temperature of the power cable, conduct the ampacity test, and analyze the cable laying method and depth, soil temperature, Soil thermal resistance coefficient, cable spacing and irradiation strength and other test conditions, the impact on the current carrying capacity of power cables. According to the real-time monitoring temperature of the cable, the alarm can be made when the cable temperature is too high or the temperature rise speed is too fast. And on the basis of determining the working temperature and load operating conditions of the cable conductor core, dynamically calculate the current carrying capacity of the cable, which is conducive to improving the performance of the power cable and increasing the load capacity of the power cable.
Simulation analysis of electromagnetic-temperature field coupling of medium voltage switchgear based on finite element method
Authors: Li Peng , Jia Tingbo , Zhang Zhongyu , Li Wentao , Gao Ying , Zheng Nan
Published: November 2020

In order to study the electric field distribution and temperature distribution of medium-voltage switchgear under normal operating conditions, taking 10kV switchgear as an example. Firstly, a three-dimensional physical model was established based on the solid structure of the switchgear. Secondly, the switchgear was made using the finite element method to simulate and analyze the electromagnetic field and temperature field. Consider various factors that affect the electric field distribution, and obtain the electric field distribution inside the switchgear and the temperature field distribution map on the current-carrying circuit.
A microgrid alarm processing method based on equipment fault prediction and improved support vector machine learning
Authors: Yuan Haochen , Zhang Zehai , Yuan Peng , Wang Shiqian , wang Lili , Yuan Yutong
Published: November 2020

Microgrids are important parts of modern strong intelligent power system. In recent years, new energy sources have developed rapidly in China, and research on microgrid technologies is in the ascendant. The typical microgrid has obvious advantages such as flexible network structure and small circuit loss. With its increasing scale and increasing application in the power system, it needs to be dealt with the complex operation mode. In order to achieve efficient operation and management, microgrid control still needs to be equipped with energy management system (EMS). One of the main problems that EMS needs to solve is the generation of massive alarm information within a short period of time after equipment failure. To this end, this paper proposes a microgrid alarm processing method based on equipment fault prediction and improved support vector machine learning. Based on historical operation risk and health state evaluation, the equipment fault prediction is carried out. Then we optimize and select kernel function for machine learning and have an improved SVM model. With this model, fault equipment sets are classified and verified so we can get the accurate source alarm and fault equipment. Finally, the validity and accuracy of this method are verified by a simple example.
Research on improved voltage-type rotor flux linkage observer method for engineering application
Authors: He Gang , Dong Xingyan , Wang Hui , Zhao Zhigang , Luo Zhiwei
Published: November 2020

Accurate rotor flux linkage observation is conducive to high-performance control of the motor. Among them, the voltage-type rotor flux linkage observer is widely used in engineering practice because of its simple structure and no need for speed information. However, the traditional voltage-type rotor flux linkage observer has an inherent pure integrator, which will affect the accuracy of flux linkage observation. This paper analyses the common low-pass filter instead of pure integrator, and the improved method of high-low-pass filter series compensation. Then, focus on derivation to get an improved voltage-type rotor flux linkage observer based on DC offset compensation. Finally, based on the theoretical analysis, the magnetic flux observation effects of the four observers are simulated and verified. The result proves that the method proposed in this paper can realize the accurate observation of the rotor flux linkage.
Study on the DFT-based phasor estimation algorithm for removal of the decaying DC offset
Authors: Peng Fang , Li Chong , Wang Wenjing
Published: November 2020

Protection relays respond to the fault condition of power system using real-time voltage and current signals. Estimation of the voltage and current phasors is necessary. However, the decaying DC component contained in the signal causes overshoot and oscillations in the magnitude and angle of the phasor estimated by the traditional DFT algorithm. Two types of estimation algorithms removing effect of the decaying DC component are studied and compared in this paper. The two improved algorithms include an error estimation (EE) algorithm featured with estimating the decaying DC component characteristics and a differential DFT (DD) algorithm featured with prefiltering of the current signal prior to phasor estimation. Performance of the two algorithms is evaluated using simulated signals from Matlab and PSCAD software. Accuracy of the phasor estimation is improved and the DD algorithm has more excellent performance than the EE algorithm.
Research on the Construction of Credit Evaluation System for Safety Performance
Authors: Yang Bo , Xie Huan , Zhao Lei , Zhu Rong , Ye Kuan , Li Hongbin , Li Dazhi , Ren Zhigang
Published: November 2020

In light of the fundamental requirements of the safe development of power grid enterprises, this paper introduces the concept of “credit” to innovatively put forward the concept of “responsibility credit” for the implementation of safety production responsibilities and the establishment of a credit evaluation system for safety performance from three dimensions: integrity, compliance and execution. Owing to the “refinement and implementation of the safety responsibility list, carrying out safety performance credit evaluation, and implementing the safety performance responsibility reward and punishment mechanism”, the safety performance management model pertaining to “knowledge, action, evaluation, optimization, performance” is formed to provide a reference for improving the intrinsic safety management in the power grid system.
Based on Optimized Mag-thermal Coupling Method Simulation Research on Temperature Rise of Switching Power Transformer
Authors: Qian Jiahao , Wang Xuming , Huang Liqiu , Xu Hong , Lou Jianyong
Published: November 2020

In this study, a bidirectional mag-thermal coupling method is used to simulate the temperature rise of the switching power supply transformer. According to the loss and temperature rise characteristics of the transformer, theoretical analysis and simulation are carried out. A set of optimized windings and design methods based on the upper limit of temperature rise are proposed. The simulation results show that the optimized windings reduce the winding loss, and improve the efficiency of the transformer by 5%, and reduce the temperature rise by 10%. The average temperature rise curve is consistent with the experimental ones of the transformer. Compared with unidirectional coupling, the method greatly improves the simulation accuracy by 4%. This research has certain guiding significance for the thermal design of switching power transformer.
Analysis of coupling factors between high proportion wind power and ultra-high voltage DC
Authors: Fan Guowei , Fan Guoqi , Song Pengfei , Ren Chong , Kang Pengpeng , Cheng Lin , Zhang Facai
Published: November 2020

Due to the imperfect construction of supporting thermal power units, when wind power sources are in full swing, if DC low-power operation will inevitably lead to wind power abandonment, if DC high power operation is subject to fault transient overvoltage operation constraints, it will also cause power curtailment of wind power sources. In order to promote wind power consumption and lean management of DC influencing factors, this paper analyzes the number of supporting thermal units started, supporting unit power changed, wind power and connected substation power to find out the key factors of DC operating limit and wind power consumption. The validity of this paper was verified by a DC power grid simulation in a certain area.
Development of AT Traction Network Short Circuit Calculation Software Based on BS Architecture
Authors: Yang Haobo , Li Chenchen , Zhu Qinghua , Sun Qihang , Zhao Yinhua
Published: November 2020

In order to meet the production needs of the gradually developing electrified railway, an AT traction network short circuit calculation system based on B/S (Browser/Server) three-layer network structure is designed. Make full use of network resources, simplify the operability and arbitrariness of short-circuit calculation, and realize the timely storage and recall of data to facilitate management and statistical analysis.
Experimental study on friction coefficient of liquid film lubricated mechanical seals with laser micro-texturing
Authors: Fang Guifang , Jin Liang , Wei Long
Published: November 2020

The friction coefficient was a key parameter for expressing the friction characteristics of the seal faces. The friction coefficient of the end faces of unbalanced mechanical seals with laser-textured micro-pores surface and spiral grooves surface were tested on the self-designed mechanical seal testing device, and compared with conventional smooth surface contacting mechanical seal. The experimental sealed medium was 25 °C water, the sealed medium pressures p=03 ∼ 0.9 MPa, and the rotating speeds n=1000 ∼ 3000 rpm. A series of experimental data of friction coefficient were obtained through experiments under different medium pressures and rotating speeds. The experimental results show that the friction coefficient of mechanical seals with laser surface micro-texturing were significantly lower than that of smooth surface mechanical seal, and the effect of spiral grooves end face on improve friction characteristics was better than that of micro-pores end face. Both medium pressure and rotating speed had influenced on the friction coefficient of mechanical seals with laser surface micro-texturing. The friction coefficient of micro-textured end face decreased with the increasing medium pressure, and it first decreased with the increasing rotating speed, and changes little when the rotating speed reaches a certain value.
Section 44 of the English Arbitration Act 1996 and third parties to arbitration
Authors: Burn George , Cheung Kevin
Published: November 2020

Court-ordered interim measures serve to reinforce and support tribunals’ jurisdiction and powers. Practitioners have long understood that national courts can and should apply this supportive jurisdiction against third parties to arbitration over whom most tribunals lack power. However, since 2014, English courts have held, in a series of first instance decisions, that their powers under section 44 of the English Arbitration Act 1996 are not exercisable against third parties to arbitration. Save for one of the powers under section 44, which the Court of Appeal has recently held to be applicable to third parties, this judicial interpretation that section 44 is not applicable to third parties remains in place. The authors argue that this judicial interpretation of section 44 runs contrary to its underlying purpose and the role of the courts in arbitration, and leaves a gap in a regime known for its supportive attitude vis-à-vis arbitration.
FireProtASR: A Web Server for Fully Automated Ancestral Sequence Reconstruction
Authors: Musil Milos , Khan Rayyan Tariq , Beier Andy , Stourac Jan , Konegger Hannes , Damborsky Jiri , Bednar David
Published: November 2020

There is a great interest in increasing proteins’ stability to widen their usability in numerous biomedical and biotechnological applications. However, native proteins cannot usually withstand the harsh industrial environment, since they are evolved to function under mild conditions. Ancestral sequence reconstruction is a well-established method for deducing the evolutionary history of genes. Besides its applicability to discover the most probable evolutionary ancestors of the modern proteins, ancestral sequence reconstruction has proven to be a useful approach for the design of highly stable proteins. Recently, several computational tools were developed, which make the ancestral reconstruction algorithms accessible to the community, while leaving the most crucial steps of the preparation of the input data on users’ side. FireProtASR aims to overcome this obstacle by constructing a fully automated workflow, allowing even the unexperienced users to obtain ancestral sequences based on a sequence query as the only input. FireProtASR is complemented with an interactive, easy-to-use web interface and is freely available at https://loschmidt.chemi.muni.cz/fireprotasr/.
Evolutionary History Drives Biogeographic Patterns of Coral Reef Resilience
Authors: Roff George
Published: November 2020

Modern-day Indo-Pacific coral reefs are characterized by rapid recovery driven by pulses of coral recruitment, but Caribbean reefs exhibit low rates of recruitment and poor recovery following a wide range of disturbance events. The contrasting evolutionary history of coral taxa offers key insight into biogeographic patterns of coral resilience. Following the closure of the Isthmus of Panama approximately 2.8 million years ago, widespread extinction of Caribbean corals led to an evolutionary bottleneck that favored large and long-lived species with a relatively high reliance on asexual versus sexual reproduction. In contrast, adaptive radiation led to the evolution of superrecruiting tabular, digitate, and corymbose corals that drive the rapid recovery of modern-day Indo-Pacific reefs following disturbance. The dominance of branching growth forms and evolutionary absence of superrecruiting growth forms throughout the entire evolutionary history of the Caribbean (approximately 38 million years ago to present) may explain the exceptionally high recruitment rates on modern-day Indo-Pacific reefs and low historical recruitment on Caribbean reefs. The evolutionary history of the Caribbean coral reef-building taxa implies that, even with a reversal of ecosystem state, widespread recovery of Caribbean reefs may be limited.
Prefrontal Granule Cell-Related Genes and Schizophrenia
Authors: Liu Huaigui , Xu Lixue , Fu Jilian , Su Qian , Liu Nana , Xu Jiayuan , Tang Jie , Li Wei , Zhao Fangshi , Ding Hao , Liu Feng , Qin Wen , Yu Chunshui
Published: November 2020

Although both the granular layer of the prefrontal cortex (PFC) and schizophrenia are unique in primates, especially humans, their linkage is unclear. Here, we tested whether schizophrenia is associated with expression profiles of the granule cell (GC)-related genes in the human PFC. We identified 14 candidate GC-related genes with gradually increased expression levels along the gradient of the agranular, dysgranular, light-granular, and granular prefrontal regions based on the densely sampled gene expression data of 6 postmortem human brains, and with more than 10-fold expression in neurons than other cell types based on the single-cell RNA-sequencing data of the human PFC. These GC-related genes were functionally associated with synaptic transmission and cell development and differentiation. The identified 14 GC-related genes were significantly enriched for schizophrenia, but not for depression and bipolar disorder. The expression levels of the 4 stable schizophrenia- and GC-related genes were spatially correlated with gray matter volume differences in the PFC between patients with schizophrenia and healthy controls. This study provides a set of candidate genes for the human prefrontal GCs and links expression profiles of the GC-related genes to the prefrontal structural impairments in schizophrenia.
PDE limits of stochastic SIS epidemics on networks
Authors: Di Lauro F , Croix J-C , Berthouze L , Kiss I Z
Published: November 2020

Stochastic epidemic models on networks are inherently high-dimensional and the resulting exact models are intractable numerically even for modest network sizes. Mean-field models provide an alternative but can only capture average quantities, thus offering little or no information about variability in the outcome of the exact process. In this article, we conjecture and numerically demonstrate that it is possible to construct partial differential equation (PDE)-limits of the exact stochastic susceptible-infected-susceptible epidemics on Regular, Erdős–Rényi, Barabási–Albert networks and lattices. To do this, we first approximate the exact stochastic process at population level by a Birth-and-Death process (BD) (with a state space of $O(N)$ rather than $O(2^N)$) whose coefficients are determined numerically from Gillespie simulations of the exact epidemic on explicit networks. We numerically demonstrate that the coefficients of the resulting BD process are density-dependent, a crucial condition for the existence of a PDE limit. Extensive numerical tests for Regular, Erdős–Rényi, Barabási–Albert networks and lattices show excellent agreement between the outcome of simulations and the numerical solution of the Fokker–Planck equations. Apart from a significant reduction in dimensionality, the PDE also provides the means to derive the epidemic outbreak threshold linking network and disease dynamics parameters, albeit in an implicit way. Perhaps more importantly, it enables the formulation and numerical evaluation of likelihoods for epidemic and network inference as illustrated in a fully worked out example.
Evangelicalism and Empire: Rudyard Kipling on the Roman Cult of Mithras and Christianization
Authors: Walsh* David
Published: November 2020

Among the works of Rudyard Kipling, there are several short stories set in the Roman World that feature characters who are members of the cult of Mithras. These stories also involve Christian characters, but while the Mithraic initiates are loyal servants of the Roman Empire, the Christians create and attract disorder. The aim of this article is to explore why Kipling chose to make the heroic characters of these stories Mithraic initiates, and present the Christians in a less positive light. It will be argued that Kipling was attacking Christian evangelicals, who he disliked due to his experiences at the hands of one as a child, and also because of the difficult relationship between Christian missionaries and British imperial administrators, especially in the aftermath of the 1857 Indian Mutiny. In contrast, Kipling’s Mithras cult acknowledges that there are ‘many ways to the light’, and, moreover, by inferring that there are many similarities between the cult of Mithras and Christianity, Kipling hoped to urge evangelical Christians to moderate their behaviour and use his depiction of the Mithras cult as an example of how to better approach religious diversity within the Empire.
Coal and the European Industrial Revolution
Authors: Fernihough Alan , O'Rourke Kevin Hjortshøj
Published: November 2020

To what extent did growth during the Industrial Revolution depend on coal? We answer the question using a panel of European city sizes between 1300 and 1900. Prior to 1750, there was no relationship between proximity to coalfields and growth; after 1750 cities closer to coalfields grew substantially faster than those further away. We instrument for coal proximity using proximity to Carboniferous-era rock strata.
Harmonizing research outcomes for polycystic ovary syndrome (HARP), a marathon not a sprint: current challenges and future research need
Authors: Al Wattar Bassel H , Bueno Aurora , Martin Miguel Garcia , Ibáñez Naomi Cano , Harasani Klejda , Garad Rhonda , Franks Steve , Balen Adam , Bhide Priya , Piltonen Terhi , Romualdi Daniela , Laven Joop , Moss Ngawai , Andrews Caroline , Hawkes Rachel , Mol Ben W , Teede Helena , Thangaratinam Shakila , Khan Khalid Saeed
Published: November 2020

Investing in clinical research and evidence-based medicine has helped to improve the care for women with polycystic ovary syndrome (PCOS). However, several important questions remain unanswered on the optimal prevention and management strategies for PCOS. Addressing this uncertainty is often hindered by suboptimal research conduct leading to inefficient evidence synthesis and research wastage. PCOS research is often practised by varied specialized teams in silo leading to disharmonious and fragmented efforts neglecting the lifelong impact of PCOS on women’s wellbeing. Poor engagement among key stakeholders and lay consumers continues to limit the impact and benefits of research to society. Selective reporting on surrogate outcomes with a ‘significant’ P-value is a common malpractice in PCOS outputs. Effective adoption of the harmonizing research outcomes for PCOS (HARP) core outcome set is needed to minimize heterogeneity in reporting and promote research excellence. Small single-centre studies offer limited value to assess the varied PCOS phenotypes. Efficient large scale data-sharing is needed to address complex research questions and glean the benefits of big data research. We propose a roadmap to address these challenges and remedy future research need by promoting patient and public involvement in PCOS research to guide research efforts and address real patients’ needs; engaging all key stakeholder groups to promote a multi-disciplinary lifelong approach to new research; continuously refining research needs and priorities to revise the knowledge gap and allocate resources judiciously; standardizing outcomes definitions and measurement tools to harmonize reporting and promote excellence in research; and by investing in large data-sharing infrastructure to facilitate big data research and govern ethical data sharing.
High-throughput phenotyping with temporal sequences
Authors: Estiri Hossein , Strasser Zachary H , Murphy Shawn N
Published: November 2020

Objective

High-throughput electronic phenotyping algorithms can accelerate translational research using data from electronic health record (EHR) systems. The temporal information buried in EHRs is often underutilized in developing computational phenotypic definitions. This study aims to develop a high-throughput phenotyping method, leveraging temporal sequential patterns from EHRs.

Materials and Methods

We develop a representation mining algorithm to extract 5 classes of representations from EHR diagnosis and medication records: the aggregated vector of the records (aggregated vector representation), the standard sequential patterns (sequential pattern mining), the transitive sequential patterns (transitive sequential pattern mining), and 2 hybrid classes. Using EHR data on 10 phenotypes from the Mass General Brigham Biobank, we train and validate phenotyping algorithms.

Results

Phenotyping with temporal sequences resulted in a superior classification performance across all 10 phenotypes compared with the standard representations in electronic phenotyping. The high-throughput algorithm’s classification performance was superior or similar to the performance of previously published electronic phenotyping algorithms. We characterize and evaluate the top transitive sequences of diagnosis records paired with the records of risk factors, symptoms, complications, medications, or vaccinations.

Discussion

The proposed high-throughput phenotyping approach enables seamless discovery of sequential record combinations that may be difficult to assume from raw EHR data. Transitive sequences offer more accurate characterization of the phenotype, compared with its individual components, and reflect the actual lived experiences of the patients with that particular disease.

Conclusion

Sequential data representations provide a precise mechanism for incorporating raw EHR records into downstream machine learning. Our approach starts with user interpretability and works backward to the technology.
Performance Information, Racial Bias, and Citizen Evaluations of Government: Evidence from Two Studies
Authors: Porumbescu Gregory A , Piotrowski Suzanne J , Mabillard Vincent
Published: November 2020

Social accountability reforms emphasize expanding performance information disclosure and incorporating citizen feedback into performance evaluations of public organizations. However, social accountability scholarship has largely ignored possible discriminatory implications of performance information use despite calls for more social equity research. We look to bridge these two literatures, arguing that increasing exposure to performance information can actually activate racial bias in citizen feedback. Using two samples of White MTurk participants residing in the United States, we test this argument in a Negative Performance Information Study (n = 800) and a Positive Performance Information Study (n = 800). In the Negative Performance Information Study, we find increased exposure to negative performance information triggers more negative performance evaluations of public organizations led by Black public managers, but not White public managers, and strengthens preferences to fire Black public managers, but not White public managers. In the Positive Performance Information Study, we find increased exposure to positive performance information has no impact on performance evaluations of Black, nor White public managers but strengthens preferences to reappoint White, but not Black public managers. These findings suggest increasing exposure to performance information triggers racial bias in performance evaluations and preferences for holding public managers accountable.
QPOs in compact binaries from small-scale eruptions in an inner magnetized disc
Authors: Scepi Nicolas , Begelman Mitchell C , Dexter Jason
Published: November 2020

Dwarf novæ (DNe) and low-mass X-ray binaries (LMXBs) are compact binaries showing variability on time-scales from years to less than seconds. Here, we focus on explaining part of the rapid fluctuations in DNe, following the framework of recent studies on the monthly eruptions of DNe that use a hybrid disc composed of an outer standard disc and an inner magnetized disc. We show that the ionization instability, which is responsible for the monthly eruptions of DNe, is also able to operate in the inner magnetized disc. Given the low density and the fast accretion time-scale of the inner magnetized disc, the ionization instability generates small, rapid heating and cooling fronts propagating back and forth in the inner disc. This leads to quasi-periodic oscillations (QPOs) with a period of the order of 1000 s. A strong prediction of our model is that these QPOs can only develop in quiescence or at the beginning/end of an outburst. We propose that these rapid fluctuations might explain a subclass of already observed QPOs in DNe as well as a, still to observe, subclass of QPOs in LMXBs. We also extrapolate to the possibility that the radiation pressure instability might be related to type B QPOs in LMXBs.
The complex fossil magnetic field of the δ Scuti star HD 41641
Authors: Thomson-Paressant K , Neiner C , Zwintz K , Escorza A
Published: November 2020

Only three magnetic δ Scuti stars are known as of today. HD 41641 is a δ Scuti star showing chemical peculiarities and rotational modulation of its light curve, making it a good magnetic candidate. We acquired spectropolarimetric observations of this star with NARVAL at Télescope Bernard Lyot (TBL) to search for the presence of a magnetic field and characterize it. We indeed clearly detect a magnetic field in HD 41641, making it the fourth known magnetic δ Scuti star. Our analysis shows that the field is of fossil origin, like magnetic OBA stars, but with a complex field structure rather than the much more usual dipolar structure.
The Herschel SPIRE Fourier Transform Spectrometer Spectral Feature Finder – V. Rotational measurements of NGC 891
Authors: Benson Chris S , Spencer L D , Valtchanov I , Scott J , Hładczuk N
Published: November 2020

The ESA Herschel Spectral and Photometric Imaging Receiver (SPIRE) Fourier Transform Spectrometer (FTS) Spectral Feature Finder (FF) project is an automated spectral feature fitting routine developed within the SPIRE instrument team to extract all prominent spectral features from all publicly available SPIRE FTS observations. In this work, we demonstrate the use of the FF information extracted from three observations of the edge-on spiral galaxy NGC 891 to measure the rotation of N ii and C i gas at far-infrared frequencies in complement to radio observations of the [H i] 21-cm line and the CO(1-0) transition as well as optical measurements of Hα. We find that measurements of both N ii and C i gas follow a similar velocity profile to that of H i and Hα showing a correlation between neutral and ionized regions of the interstellar medium in the disc of NGC 891.
The elephant in the bathtub: when the physics of star formation regulate the baryon cycle of galaxies
Authors: Gensior Jindra , Kruijssen J M Diederik
Published: November 2020

In simple models of galaxy formation and evolution, star formation is solely regulated by the amount of gas present in the galaxy. However, it has recently been shown that star formation can be suppressed by galactic dynamics in galaxies that contain a dominant spheroidal component and a low gas fraction. This ‘dynamical suppression’ is hypothesized to also contribute to quenching gas-rich galaxies at high redshift, but its impact on the galaxy population at large remains unclear. In this paper, we assess the importance of dynamical suppression in the context of gas regulator models of galaxy evolution through hydrodynamic simulations of isolated galaxies, with gas-to-stellar mass ratios of 0.01–0.20 and a range of galactic gravitational potentials from disc-dominated to spheroidal. Star formation is modelled using a dynamics-dependent efficiency per free-fall time, which depends on the virial parameter of the gas. We find that dynamical suppression becomes more effective at lower gas fractions and quantify its impact on the star formation rate as a function of gas fraction and stellar spheroid mass surface density. We combine the results of our simulations with observed scaling relations that describe the change of galaxy properties across cosmic time, and determine the galaxy mass and redshift range where dynamical suppression may affect the baryon cycle. We predict that the physics of star formation can limit and regulate the baryon cycle at low redshifts (z ≲ 1.4) and high galaxy masses (M* ≳ 3 × 1010 M⊙), where dynamical suppression can drive galaxies off the star formation main sequence.
Dynamical structure of highly eccentric discs with applications to tidal disruption events
Authors: Lynch Elliot M , Ogilvie Gordon I
Published: November 2020

Whether tidal disruption events circularize or accrete directly as highly eccentric discs is the subject of current research and appears to depend sensitively on the disc thermodynamics. One aspect of this problem that has not received much attention is that a highly eccentric disc must have a strong, non-hydrostatic variation of the disc scale height around each orbit. As a complement to numerical simulations carried out by other groups, we investigate the dynamical structure of TDE discs using the non-linear theory of eccentric accretion discs. In particular, we study the variation of physical quantities around each elliptical orbit, taking into account the dynamical vertical structure, as well as viscous dissipation and radiative cooling. The solutions include a structure similar to the nozzle-like structure seen in simulations. We find evidence for the existence of the thermal instability in highly eccentric discs dominated by radiation pressure. For thermally stable solutions many of our models indicate a failure of the α-prescription for turbulent stresses. We discuss the consequences of our results for the structure of eccentric TDE discs.
An Experimental Test of Adaptive Introgression in Locally Adapted Populations of Splash Pool Copepods
Authors: Griffiths Joanna S , Kawji Yasmeen , Kelly Morgan W
Published: November 2020

As species struggle to keep pace with the rapidly warming climate, adaptive introgression of beneficial alleles from closely related species or populations provides a possible avenue for rapid adaptation. We investigate the potential for adaptive introgression in the copepod, Tigriopus californicus, by hybridizing two populations with divergent heat tolerance limits. We subjected hybrids to strong heat selection for 15 generations followed by whole-genome resequencing. Utilizing a hybridize evolve and resequence (HER) technique, we can identify loci responding to heat selection via a change in allele frequency. We successfully increased the heat tolerance (measured as LT50) in selected lines, which was coupled with higher frequencies of alleles from the southern (heat tolerant) population. These repeatable changes in allele frequencies occurred on all 12 chromosomes across all independent selected lines, providing evidence that heat tolerance is polygenic. These loci contained genes with lower protein-coding sequence divergence than the genome-wide average, indicating that these loci are highly conserved between the two populations. In addition, these loci were enriched in genes that changed expression patterns between selected and control lines in response to a nonlethal heat shock. Therefore, we hypothesize that the mechanism of heat tolerance divergence is explained by differential gene expression of highly conserved genes. The HER approach offers a unique solution to identifying genetic variants contributing to polygenic traits, especially variants that might be missed through other population genomic approaches.
Bacterial tRNA 2′-O-methylation is dynamically regulated under stress conditions and modulates innate immune response
Authors: Galvanin Adeline , Vogt Lea-Marie , Grober Antonia , Freund Isabel , Ayadi Lilia , Bourguignon-Igel Valerie , Bessler Larissa , Jacob Dominik , Eigenbrod Tatjana , Marchand Virginie , Dalpke Alexander , Helm Mark , Motorin Yuri
Published: November 2020

RNA modifications are a well-recognized way of gene expression regulation at the post-transcriptional level. Despite the importance of this level of regulation, current knowledge on modulation of tRNA modification status in response to stress conditions is far from being complete. While it is widely accepted that tRNA modifications are rather dynamic, such variations are mostly assessed in terms of total tRNA, with only a few instances where changes could be traced to single isoacceptor species. Using Escherichia coli as a model system, we explored stress-induced modulation of 2′-O-methylations in tRNAs by RiboMethSeq. This analysis and orthogonal analytical measurements by LC-MS show substantial, but not uniform, increase of the Gm18 level in selected tRNAs under mild bacteriostatic antibiotic stress, while other Nm modifications remain relatively constant. The absence of Gm18 modification in tRNAs leads to moderate alterations in E. coli mRNA transcriptome, but does not affect polysomal association of mRNAs. Interestingly, the subset of motility/chemiotaxis genes is significantly overexpressed in ΔTrmH mutant, this corroborates with increased swarming motility of the mutant strain. The stress-induced increase of tRNA Gm18 level, in turn, reduced immunostimulation properties of bacterial tRNAs, which is concordant with the previous observation that Gm18 is a suppressor of Toll-like receptor 7 (TLR7)-mediated interferon release. This documents an effect of stress induced modulation of tRNA modification that acts outside protein translation.
Repressor Activity of SqrR, a Master Regulator of Persulfide-Responsive Genes, Is Regulated by Heme Coordination
Authors: Shimizu Takayuki , Hayashi Yuuki , Arai Munehito , McGlynn Shawn E , Masuda Tatsuru , Masuda Shinji
Published: November 2020

Reactive sulfur species (RSS) are involved in bioactive regulation via persulfidation of proteins. However, how cells regulate RSS-based signaling and RSS metabolism is poorly understood, despite the importance of universal regulation systems in biology. We previously showed that the persulfide-responsive transcriptional factor SqrR acts as a master regulator of sulfide-dependent photosynthesis in proteobacteria. Here, we demonstrated that SqrR also binds heme at a near one-to-one ratio with a binding constant similar to other heme-binding proteins. Heme does not change the DNA-binding pattern of SqrR to the target gene promoter region; however, DNA-binding affinity of SqrR is reduced by the binding of heme, altering its regulatory activity. Circular dichroism spectroscopy clearly showed secondary structural changes in SqrR by the heme binding. Incremental change in the intracellular heme concentration is associated with small, but significant reduction in the transcriptional repression by SqrR. Overall, these results indicate that SqrR has an ability to bind heme to modulate its DNA-binding activity, which may be important for the precise regulation of RSS metabolism in vivo.
Effects of a novel E. coli phytase expressed in Pseudomonas fluorescens on growth, bone mineralization, and nutrient digestibility in pigs fed corn–soybean meal diets
Authors: Ren Ping , Blavi Laia , González-Vega Caroline , Liu Yanhong , Hancock Deana , Vazquez-Añón Mercedes , Almeida Ferdinando N , Stein Hans H
Published: November 2020

Two studies were conducted to determine the effects of a novel Escherichia coli phytase expressed in Pseudomonas fluorescens on growth performance, bone mineralization, and nutrient digestibility in pigs fed corn-soybean meal diets. In experiment 1, 160 nursery pigs (9.79 ± 1.22 kg) were randomly allotted to one of four treatments with 10 pens per treatment and four pigs per pen. Phase I and phase II diets were provided from d 0 to d 14 and d 14 to d 28, respectively. Treatments included: positive control (PC) with all nutrients meeting requirements; negative control (NC) with standardized total tract digestible (STTD) P reduced by 0.15% and 0.14% compared with PC in phase I and phase II, respectively; and NC diets containing 250 or 500 units of phytase (FTU) per kilogram. Results demonstrated that pigs fed PC had greater (P < 0.01) ADG and G:F for the overall experimental period, and greater (P < 0.01) bone ash and P concentrations, compared with pigs fed NC or diets with phytase supplementation. Pigs fed diets containing phytase had greater (P < 0.01) ADG and G:F for the overall experimental period compared with pigs fed the NC diet without phytase, and bone ash and P weights were increased (P < 0.01) as well. In experiment 2, 63 growing barrows (56.25 ± 2.54 kg) were blocked by BW and randomly allotted to one of seven treatments with nine pens per treatment and one pig per pen. A basal corn–soybean meal diet was formulated to meet nutrient requirements for growing pigs with the exception that STTD P was reduced by 0.18% compared with the requirement, and Ca was included to achieve a Ca:STTD P ratio of 2.15. Six additional diets were formulated by adding 250, 500, 750, 1,000, 1,500, or 2,000 FTU/kg of phytase to the basal diet. Pigs were fed experimental diets for 12 d with 7 d of adaptation and 5 d of fecal sample collection. Results indicated that there was a linear (P < 0.01) increase in apparent total tract digestibility of ash and ether extract, and STTD of Ca and P also increased (linear, P < 0.05) in response to increasing doses of phytase. Increasing phytase levels in the diets resulted in increase (quadratic, P < 0.05) in apparent ileal digestibility of Arg, His, Ile, Lys, Trp, Asp, and Glu. In conclusion, the novel E. coli phytase was effective in increasing growth performance, bone mineralization, and Ca and P digestibility in pigs fed corn–soybean meal-based diets. Results also indicated that this phytase had the potential to enhance the digestibility of fat and certain AA.
Patterns of dengue in Nepal from 2010–2019 in relation to elevation and climate
Authors: Gyawali Narayan , Johnson Brian J , Dixit Sameer M , Devine Gregor J
Published: November 2020

Background

Understanding and describing the regional and climatic patterns associated with increasing dengue epidemics in Nepal is critical to improving vector and disease surveillance and targeting control efforts.

Methods

We investigated the spatial and temporal patterns of annual dengue incidence in Nepal from 2010 to 2019, and the impacts of seasonal meteorological conditions (mean maximum, minimum temperature and precipitation) and elevation on those patterns.

Results

More than 25 000 laboratory-confirmed dengue cases were reported from 2010 to 2019. Epidemiological trends suggest that dengue epidemics are cyclical with major outbreaks occurring at 2- to 3-y intervals. A significant negative relationship between dengue incidence and increasing elevation (metres above sea level) driven by temperature was observed (p<0.05) with dengue risk being greatest below 500 m. Risk was moderate between 500 and 1500 m and decreased substantially above 1500 m. Over the last decade, increased nightly temperatures during the monsoon months correlated with increased transmission (p<0.05). No other significant relationship was observed between annual dengue cases or incidence and climatological factors.

Conclusions

The spatial analysis and interpretation of dengue incidence over the last decade in Nepal confirms that dengue is now a well-established public health threat of increasing importance, particularly in low elevation zones and urbanised areas with a tropical or subtropical climate. Seasonal variations in temperature during the monsoon months are associated with increased transmission.
PD-1 inhibitors might limit the development of brain metastases in patients with advanced melanoma
Authors: Marcaillou Marion , Linder Clara , Chaltiel Léonor , Sibaud Vincent , Pagès Cécile , Modesto Anouchka , Chira Ciprian , Dalmasso Céline , Boulinguez Serge , Bedane Christophe , Meyer Nicolas
Published: November 2020

Brain metastases are a common and severe complication potentially leading to death in patients with metastatic melanoma. Immunotherapy and targeted therapy have significantly improved progression-free survival (PFS) and overall survival (OS) in patients with advanced melanoma. Few studies focus on patients with central nervous system (CNS) metastases, and these patients are often excluded and have a poor prognosis. It has been suggested that immunotherapy could reduce the incidence of brain metastases. We tested this hypothesis in a retrospective bicentric study. We performed a retrospective, bicentric descriptive analysis on a cohort of 293 patients treated for metastatic melanoma between May 2014 and October 2017 (Toulouse, N = 202; Limoges, N = 91). Patients with brain metastasis at diagnosis were excluded from the analysis. Patients were separated into two groups according to the first line of treatment: immunotherapy [immune checkpoint inhibitor (ICI)] vs other and anti-PD-1 vs other. The primary endpoint was the cumulative incidence of brain metastases, and secondary endpoints were OS and PFS. At 12 months, the cumulative incidence of brain metastases was 13.78% in the ICI group [95% confidence interval (CI) 9.14–19.36] and 27.26% in the other group (95% CI 19.38–35.71), P = 0.004. The cumulative incidence was 9.49% in the anti-PD-1 group (95% CI 5.43–14.90) vs 30.11% in the other group (95% CI 22.59–37.97), P < 0.0001. In multivariable analysis (model with 277 patients), anti-PD-1 reduced the risk of brain metastases by almost 70% (hazard ratio = 0.29, 95% CI 0.15–0.56, P < 0.0001). The use of ICI (anti-PD-1/PD-L1) in advanced melanomas without initial brain metastasis shows a protective effect and prevents their occurrence.