bluuebunny/crossref_metadata_2025 huggingface dataset:
Design of Ripple Power Supply for Aging Test of DC Arrester
Authors: Li Longlong , Li Guofu , Chen Mo , Li Yongliang , Liu Zhifang
Published: July 2019

The reliability of DC arresters is one of the basis of safe operation for HVDC transimission system, the aging test is the main measure to obtain the reliability of arresters, and therefore, is of great importance. The test voltage with ideal waveforms had not been produced before by any of the test equipment when it is loaded. The paper introduces a method to produce the aging test ripple voltage waveforms of 6 pulses and 12 pulses converter which fully considers the influence of trigger angle and commutation angle. The paper designed a kind of ripple voltage power source which can series, and produce the ripple waveform of any trigger angle and commutation angle, the output voltage of one module is up to 1kV. The device went through 1000 hours of testing, and commutation process can be seen in the oscillograph clearly, including stable commutation overshoot. The oscillograph also show that the fundamental frequency of the waveform is stable, and waveform distortion is small and can be ignored. The output voltage meets the requirements of aging test for various types of DC arresters.
Analysis of Impact of Electric Vehicle Charging Load on City Grid
Authors: Zhang Yue , Dai Xianzhong , Han Xinyang , Jin Xiaoling
Published: July 2019

With the rapid development of electric vehicles, increasing electric vehicle charging load will have extensive impacts on the power grid. This paper innovatively analyzed the impact of charging load on the urban power grid by taking the power grid of a large city as an example. Firstly, the scale of electric vehicles is predicted. Secondly, considering the travelling characteristics of electric vehicles, the charging load characteristics of electric vehicles in different functional areas of the city were analyzed. Finally, the impact of unordered charging of electric vehicles on urban power grid is quantitatively analyzed from four aspects, including load structure, on-peak and off-peak difference of system, distribution network utilization rate, charging facilities and supporting network construction. Electric vehicle charging will change the load structure of the power grid, reduce the utilization rate of distribution network and investment efficiency, increase the on-peak and off-peak difference of system etc.
Simulation of Potential Distribution and Leakage Current of 800kV DC Arrester under Different Degrees of Degradation
Authors: Zhang Pipei , Shi Wei , Wang Hui , Sun Jingwen , Wang Peng
Published: July 2019

800kV DC arrester is widely used in UHV converter stations. If long-term damp or breakdown short-circuit of the resistor is degraded during operation, the potential distribution of the arrester is unreasonable and the leakage current increases, resulting in arrester heating or even explosion, so it’s necessary to analyze and calculate the potential distribution and leakage current under different degrees of degradation. In this article, the ANSYS simulation model of 800kV DC arrester was built, which was used to calculate the potential distribution and leakage current of the arrester when long-term damp and breakdown short-circuit, and the correctness of simulation results are verified by field test of leakage current.
A Coordinate Method between the System and Bus Load Forecasting in Electricity Market Environment
Authors: Cai Qiuna , Zhang Qiaoyu , Liu Sijie , Yan Binjie , Su Binghong , Yi Jiangwen , Li Bing
Published: July 2019

In view of the problems such as excessive tensile load factor of nodal bus and overload of load flow section that often occur during the trial operation of Guangdong Electric Power Spot Market, the coordination mechanism between the system and bus load forecasting results is studied in this paper. Firstly, the time-sharing credibility coordination model of the system-bus is established based on the least square method, so as to achieve the goal of load balance between upper and lower grades and the minimum overall error. Secondly, the different classification of the time-sharing credibility model is studied to adapt to different kinds of situation. Finally, a province is taken as an example to verify the effectiveness of the proposed method, and the results show that it has certain engineering application value.
Research on Wind Power Participation in Electricity Market in Northeast China
Authors: Ma Xin , Liu Jicheng , Liu Qiong , Yu Linna , Li Chunshan , Wang Ge , Li Siyuan
Published: July 2019

In China’s current power generation plan, wind power belongs to the scope of guaranteed priority generation. But with the development of wind power industry and the promotion of electricity market construction, wind power participation in market transactions has become a trend. This paper first analyses the current situation of wind power industry under the background of electric power system reform, then introduces the situation and experience of Texas electricity market with good wind power development. According to the current situation of wind power development in Northeast China, the suggestions for wind power development are put forward and the development path of wind power in the electricity market environment is formulated.
Analysis of Dispatch Methods in Northwest Area
Authors: Wang Yanan , Wang Xiuli , Zhao Hongyang
Published: July 2019

The northwest area is full of renewable energy in China, and the development of renewable energy is rapid which brings great influence on the operation of power system. With the large-scale of renewable energy, it is difficult for energy consumption in the northwest provinces, and there still exists energy curtailment in all provinces. Renewable energy consumption in the northwest area is limited by insufficient demand, potential of sending out electricity, and peaking capacity. As the basis of system operation, the research of scheduling methods provides basic data and reference for all aspects of system operation scheduling. In order to further promote the consumption of renewable energy, we study the impact of different scheduling methods on the ability of renewable energy consumption. Combining with the actual data, we analyze and evaluate the scheduling methods, comparing the characteristics of each scheduling method, and studying its impact on renewable energy consumption. Combined with relevant calculations and analysis, the optimization suggestions for exploiting the potential of renewable energy and improving consumption space are provided.
Multicriterion optimization of processing of mill trunnion based on hierarchy analysis method
Authors: Bondarenko Y A , Bestuzheva O V
Published: July 2019

The article presents the choice of optimal method of treatment when restoring of mill trunnion based on hierarchy analysis method. The criterion for selecting optimal cutting conditions is synthesized and their relationship with processing parameters is described. Many alternatives for solving a multicriterion optimization problem are constructed, methods of processing with variable cutting conditions are proposed. Based on selected criteria, a subset of Pareto-optimal cutting conditions is found when restoring trunnion. The method of hierarchy analysis is prese000nted as a multi-criteria method of decision-making using the algorithm for assessing the degree of consistency of paired comparison matrices. The applied method of expert evaluation selects the processing parameters with a decrease in the complexity of restoration work with preservation of quality of the processed surface of mill trunnion.
Analysis of proper fluctuations of technological systems
Authors: Ershov D Y , Zlotnikov E G , Timofeev D Y
Published: July 2019

The article describes the principles of building dynamic models of technological systems with concentrated parameters with a finite number of degrees of freedom. Dynamic properties of technological system are considered taking into account elastic and inertial parameters of its elements. The model of three-mass torsional chain system and the model with progressively moving masses are used for estimation of vibrational processes in drives of the technological equipment. According to the proposed mathematical model the analysis is carried out and the forms of natural oscillatory movements in the system are revealed. Oscillations of zero, first and second eigenfrequencies are determined, for each of which sets of form of the coefficients are found that describe the system configuration in the process of free oscillations.
Diagnostics of the printed circuit board bus of a spacecraft autonomous navigation system with using the N-norms
Authors: Gazizov R R , Muhambetzhanova B S , Gazizov T T , Kvasnikov A A
Published: July 2019

The paper presents the study of the printed circuit board bus of the autonomous navigation system of a spacecraft using the amplitude criteria based on N-norms. During the study, the authors revealed the most vulnerable places on the bus by calculating the five N-norm profiles along the active conductor of the bus (in 280 segments). The results showed that the peak voltage was reduced by 6.2 % to the end of the active conductor, the signal rate changed sharply but insignificantly (within ±9.3 %) along the active conductor and reduced (by 20 %) towards its end. However, the energy characteristics of the excitation along the active conductor changed insignificantly.
Simulation of organizing and carrying out of repair for ship engineering products
Authors: Zhukov Y I , Khutornaia E V
Published: July 2019

To ensure competitiveness with foreign enterprises, there is a need to reduce production time and cost of ship engineering products (SEP). This paper presents data of simulation for a repair process of SEP. The aim of researching is the justification of functional and simulation using for organizing the process of repair of SEP during required time and with cost reduction. The paper uses methodology of structural analysis in two types of notations. To obtain the quantitative result, the GPSS World environment is used. The results in the form of histograms of the processes of maintenance and repair of SEP confirm the effectiveness of proposed technologies.
Oscillations of rigid block on supported base with coulomb friction model
Authors: Munitsyn A I , Munitsyna M A , Poznyak E V , Kuznetsov S F
Published: July 2019

The analytical solution of the problem of forced oscillation of the solid parallelepiped on a horizontal base is presented. It is assumed that the dry friction force acts on the contact line between the body and the base and the base moves harmonically in a horizontal direction. The height of the parallelepiped is assumed to be much greater than the width. Dissipation of impact is taken into account in the framework of the hypothesis of Newton. The forced oscillation modes of parallelepiped corresponding to the main resonances are found by using the averaging method. The results are shown in the form of amplitude-frequency characteristics.
Simulation thermal model of CNC machine tool operating with variable modes
Authors: Polyakov A N , Parfenov I V
Published: July 2019

The article presents the approach and the thermal modeling technique of CNC machine tools, implemented at the stage of operation. In the work, as a practical implementation of the fast modeling technology, a simulation method based on the Matlab Simulink application was used. In the work to build a thermal model of the machine tool, we used analytical solutions of the heat conduction equation. This method is applied to the machine tool operating in conditions of variable thermal processes due to varying cutting speeds. The conditions for the coordination of the thermal characteristics of the machine tool at their boundaries, corresponding to the changing spindle rotation speeds, determine the peculiarity of their construction. A feature of the implementation of the mathematical model is the use of experimental modal analysis. In this case, the modal parameters of the approximating functions are determined by solving the optimization problem. To coordinate the adjacent thermal characteristics at their borders, a special condition was adopted. Regardless of the number of temperature modes used in the model, the initial level of the first temperature mode for the next mode of operation of the machine tool was taken to be equal to the achieved level of the thermal characteristic of the machine tool at the last time interval of the current mode of operation.
Simulation of broad-side coupled modal filter with passive conductor in reference plane cutout
Authors: Samoylichenko M A , Gazizov T R
Published: July 2019

The article presents the simulation of a modal filter with broad-side coupling, having a passive conductor in reference plane cutout. The authors calculate the matrices of per-unit-length parameters L and C and investigate the influence of end terminations of the passive conductor of the modal filter. As a result, we achieve alignment and minimization of the amplitudes of the decomposed pulses and show the possibility to attenuate the input ultrashort pulse with a duration of 450 ps 4.5 times.
Structural analysis of technological processes with multivariate machining operations
Authors: Schipachev A M
Published: July 2019

This article addresses the issue of structure optimization for machining technological processes. A technological process typically offers multivariate operations. A choice of one option is an optimization problem. A mathematical solution of it is complicated since a number of optimization criteria can be present. However, a multivariate technological process can be presented as a directed graph. First, all paths of the graph are found and their length that correspond to values of certain optimization criteria are determined. Then the optimal path is selected (that is, the optimal technological process) by finding generalized optimization criteria and comparing them.
Process of granulating perlite-containing mixtures: experimental study
Authors: Shkarpetkin E A , Osokin A V
Published: July 2019

The article presents results of the experimental studies concerning the effect of technological parameters on the process of forming perlite-containing mixtures as well as physical and mechanical properties of granules based on them.
Application of the BigData technology for processing manufacturing data at smart factories of the Industry 4.0
Authors: Zakoldaev D A , Shukalov A V , Zharinov I O
Published: July 2019

The task is being studied to organize the item designing production in smart factories of the Industry 4.0 using the technology of BigData. The BigData technology is necessary to process information about the completion of theme and industrial orders. Theme and industrial orders are the sources of the industrial data at the factory. Theme orders specify the nomenclature of the products manufactured in the factory. Industrial orders specify the schedule of products and separate assembly units manufacturing. The result of the multiproduct digital manufacturing is the large amount of unstructured information that has to be processed. Processing of industrial data is conducted using specialized algorithms of BigData located in the cloud environment of a smart factory. The functional scheme of a smart factory is given to describe the components and their purpose in the level of cloud services. One cycle of a cyber and physical technological line describes the production process of a complicated item designing component.
Determining the loads acting onto a cylindrical classifier of a globe mill
Authors: Khanin S I , Solodovnikov D N , Lebakh A V
Published: July 2019

Classifying devices have been developed that allow increasing the efficiency of operation of globe mills commonly used at industrial enterprises for milling various materials. Analytical equations have been obtained for the cylindrical classifier, allowing calculating the forces acting on the grate elements depending on design and process parameters of the mill. The forces acting onto the structure of a cylindrical classifier of an industrial globe mill were calculated, their changes have been analyzed. Stress in the design of the device were determined, its wear-dependent operability has been determined.
Exergic analysis of the installation for controlled dehydration of fine particulate products
Authors: Malibekov A A , Shakhov S V , Glotova I A , Sadibaev A K , Gruzdov P V , Ryazantseva A O
Published: July 2019

An installation is designed for dehydration of fine-particulate bulk products in the active hydrodynamic mode. A thermal system for heat-mass transfer during rapeseed dehydration in the active hydrodynamic mode is assessed for thermodynamic efficiency. Diagrams of thermal and exergy balance for heat-mass transfer processes are presented and heat exchange and exergy analysis are performed. Exergy loss by rapeseed dehumidification are calculated The research results show that the greatest loss of exergy occurs due to irreversibility of dehydration processes during the phase transformation, as well as due to the pressure drop in the device.
Hydraulic heat tests of the shell and tube heat exchanger using heated liquid of higher turbulization
Authors: Kuchev L A , Nikulin N Yu , Yu Feoktistov A
Published: July 2019

A short characteristic of the heat power industry of the Russian Federation is analysed. Special attention is paid to the technological condition of the central thermal electric main lines and boiler equipment, thermal networks and heat consumption systems. Moreover, it is specified that the important heat supply equipment systems are shell and tube heat exchangers. The emphasis is that the use of shell and tube heat exchanger devices is based on reliable technical solution, financial viability, and convenience in its operation and repair. Based on the analysis of local and foreign scientists’ research, the classification of approaches of heat exchange intensification in shell and tube heat exchanger devices is propounded. The article presents the results of thermal and hydraulic tests of an intensive shell-and-tube heat exchanger with increased turbulization of the heated fluid. When carrying out tests, modern high-precision measuring devices are used. A test objective comparison of hydrodynamics (losses of pressure) and heat technical characteristics (heat transfer coefficient) of two heat exchangers has been conducted. These are serial (state standard No. 27590.) and intensive (RU 185391 patent) exchangers.
Research and improvement of the process of two-stage profiling of tubes for special purposes
Authors: Parshin S V , Parshina A A
Published: July 2019

Roll-forming process is used in manufacturing multi-beam oil tubes, while reducing their outer profile diameter and forming star-like profile. In this paper a steel tubes are studied with a drawing and pushing processes. This study gets into different issues including elastoplastic behavior, contacts and friction using finite element analysis. In simulations, a plane symmetric steady-state model is used. Numerical results are compared with experimental results. A better understanding and modelling of the behavior of materials lead to a new form of roller tool with significant advantages.
Analysis of the efficiency of telemetric systems for drilling wells
Authors: Zainagalina L Z , Petrova L V , Petrov V A
Published: July 2019

For efficient control of well drilling, it is necessary to know actual drilling conditions, parameters of the trajectory of previously drilled wells, to predict the trajectory of a new part of the well bottom, to know technological parameters in the bottom hole zone. Efficiency of the telemetry systems used for drilling wells was analyzed by calculating the economic efficiency for well drilling at the Taylakov field. Modern telemetric systems help avoid additional drilling costs and improve efficiency and reliability of well drilling.
Development of automatic systems for controlling and assessing the technological properties of grain processing products
Authors: Medvedev P V , Fedotov V A , Bochkareva I A
Published: July 2019

The paper describes an automatic system for controlling and assessing the technological properties of grain processing products during milling by computer vision methods. Optimal technological characteristics of the system are empirically established ensuring its maximum efficiency. The combined action of electrostatic fields (with voltage of 24 kV) and vibration (with frequency of 45 Hz) in the assembled testbed allows negating the conglomeration of grain milled particles. Such fast estimation of the technological properties of grain processing products allows interrupting and correcting the milling process for increased efficiency.
The mathematical description of the process of material milling in the zone of intersecting flows in a centrifugal counter-flow mill
Authors: Semikopenko I A , Vavilov D V , Vyalych S V
Published: July 2019

This article presents the analytical expression for the determination of the degree of milling of particles in a centrifugal counter-flow mill with a selective effect on the material to be milled. The degree of milling is one of the most important factors characterizing the efficiency of particle collisions in the opposite intersecting flows in the tangential sleeve. The projection w
x of the velocity of interaction of particles with an oblique impact is determined on the basis of the value of the tangential stresses in the zone of opposing intersecting flows. In this case, the density of counter-intersecting flows should be such that the collision of particles occurs in the zone of milling. The structural design of the mill rotors provides separation of the particle fluxes in the tangential sleeve depending on their size. This design of the rotors improves the efficiency of grinding and fineness of the finished product. A design diagram is given in order to describe the process of milling of a material in the zone of opposing intersecting flows. As a result of theoretical studies, the analytical expression was obtained that allows determining the degree of milling of material particles in the zone of tangential collisions depending on the design and technological parameters of a centrifugal counter-flow mill.
Development of a laser beam to the line in measuring systems
Authors: Galeev A S , Suleymanov R N , Filimonov O V
Published: July 2019

The way of laser radiation focusing on a reception matrix when carrying out measuring works applying a narrowly targeted beam is shown in this article. For example, centering the shaft (reduction to coaxiality) pump units allows preventing emergence of vibration. It is destructive for bearings. The optical scheme consists of several parallels and a photosensitive matrix of glass cylinders. We theoretically prove the possibility of using a system optically of transparent cylinders with the calculated indexes of refraction, including diameters for development of a dot laser beam to the line. At the same time the ratio “the power of a beam/power of hindrances” of a laser beam when receiving the line in close proximity to a reception matrix increases from 10-100 times. This depends on the distance between a matrix and a source of laser radiation. It allows using lasers of the 1 class with power no more than 1 mW. For the purpose of confirmation of feasibility of the developed design, experimental measurements are carried out.
Identification and evaluation of reliability factors of main oil pumps
Authors: Tynchenko V S , Bukhtoyarov V V , Tynchenko V V , Kukartsev V V , Shepeta N A
Published: July 2019

Preventative maintenance systems today are not always able to achieve projected levels of the main pumps use because of the presence of random technical, technological and statistical errors. It is necessary to identify the mean time between failures, reducing factors in situations where exploitative parameters are within the normal limits. It is offered to use statistical indexes and standard parameters for the analysis. Factor analysis defines a moderate negative correlation between the vibration velocity of the fixed pumps’ parts and the mean time between failures. Also, a weak positive correlation between vibration velocity and other parameters has been determined. The results can be used to improve preventive maintenance systems, as well as to choose the most reliable structural performance.
Main reasons of leaktightness failure of detachable flanged joints with lens seal ring
Authors: Pogodin V K , Gozbenko V E
Published: July 2019

The main indicator of the performance of any design of detachable joints is its tightness, which is ensured by pressing the sealing surfaces of its parts to each other with a certain force. The frequent depressurization of detachable joints arising in practice is explained by the difficulty of determining the force that takes into account the influence of the design features of the parts of detachable joints and the intensity of their change from external conditions and the time of operation. Work on the definition of tightness carried out by the authors is different in that they take into account changes in the contact characteristics and the mutual influence of irregularities of the contacting surfaces. Considering the results of previous studies on the relationship between the tightness of the sealing device and technological factors, it can be said that the role of these factors is very significant, but it is rather difficult to assess the joint influence of technological factors on the tightness of any one design. Development and operation of new detachable connections with a lens sealing ring should be carried out taking into account the analysis carried out in this study and the established reasons for their depressurization.
Identification of induction motor parameters with measurement errors
Authors: Ivanov D V , Sandler E A , Chertykovtseva N V , Tikhomirov E A , SemenovaY N S
Published: July 2019

This paper proposes an algorithm for estimating parameters of asynchronous traction motors in the presence of measurement errors. The presence of measurement errors of voltage and current leads to biased estimates of motor parameters. Algorithmic approach to eliminating the influence of noise is used most often as it increases the accuracy of estimates without precision current and voltage meters. Known modifications of algorithms based on the method of total least squares suggest filtering the derivatives of noise, which increases the complexity of the algorithm and also changes the statistical properties of noise. The proposed algorithm is a generalization of the total least-squares technique and does not require knowledge of the laws governing the distribution of measurement errors. The results of modeling show that the parameter estimation is highly accurate than the ordinary least square. The proposed algorithm can be used to create precision control systems, as well as to diagnose faults in electric motors by K parameters.
Perspective algorithms for the effective use of electro-osmosis for automatic installations
Authors: Porsev E G , Konyukhov V Y
Published: July 2019

The paper gives the evaluation research of performance potential of using the energy of ground aquifers for the power generation used for autonomous power consumer auxiliaries. The research to evaluate the performance potential of power generation from aquifers having the exact colloidal properties of the membrane dispersed phase and filtration ground properties was done.
Determination of fatigue resistance characteristics of helicopter rotor blade
Authors: Bokhoeva L A , Kurokhtin V Y , Rogov V E , Chermoshentseva A S
Published: July 2019

This paper presents an investigation of the fatigue resistance testing of structural elements of the helicopter by the example of testing of helicopter rotor blades samples. Endurance tests of components and structural elements of aviation equipment are the laboratory reproduction of external influences corresponding to the typical operating conditions, cyclic loading and functioning. However, these tests do not include research related to the gradual accumulation of damage leading to the emergence and propagation of cracks and construction failure. In this regard, a special interest is learning the process of cracks growth during the specimens’ full-scale tests. A brief description of the blades endurance tests process with simultaneous video shooting has been given. Stretching static load is applied to the samples, after those samples are additionally loaded by alternating bending moment. Videos of the cracks growth are processed and the data about the time of subcritical crack growth are obtained. This information is displayed as a graph. The control and measurement system is considered which is used in the process of testing for recording of values of stress occurring in tested specimens because of alternating bending load applied to them. The characteristics of fatigue strength are determined, fatigue graph is plotted, durability arithmetic mean and standard deviation are determined, assemblage of durability distribution curves, assemblage of fatigue curves and endurance distribution curve are plotted, endurance limit arithmetic mean and standard deviation are determined. The achieved results have importance for the prediction of the safe operation term of the helicopter rotor blades.
Influence of modification by nanodispersed powders on layered composite aerospace hulls and protective shields
Authors: Chermoshentseva A S , Pokrovskiy A M , Bokhoeva L A , Baldanov A B , Rogov V E
Published: July 2019

The paper presents data on the influence of nanopowder on the structure of layered composites. Different quantities of the nanomodifier, based on the nanodispersed silicon dioxide powder, were added to the composite. The experimental research has shown that modification of a small amount of silicon dioxide powder (mass fraction of concentration 0.3 wt. %) is effective for using the layered composite aerospace hulls and protective shields.
Comparative evaluation of corrosion resistance of wheel and rail steels in various media
Authors: Guseva E A , Kargapoltsev S K , Balanovskiy A E , Karlina A I , Shtayger M G , Gozbenko V E , Konstantinova M V , Sivtsov A V
Published: July 2019

In order to increase the service life of rolling stock parts and rails, it is necessary to know the value of the corrosion rate of alloys in various media. In this work, the corrosion resistance of various alloys, used in railway transport, was investigated. To determine the rate of corrosion, a polarization method with the use of the potentiostat-galvanostat “Pi 50-Pro” was used. The value of the corrosion rate was determined on the basis of processing of the polarization curves with the use of the graphical method. To control the obtained results, corrosion rate was determined by decrease of the mass of samples, made from the same alloys (gravimetric method). Obtained results showed high convergence. Studies were carried out in a simulated solution. Based on a comparison of the values of the corrosion rate, the most resistant steels were determined. Corrosion resistance increases in series: 09G2S, 110G13L, St3ps, 55G, 60G, M76T, E76KHSF12KH1, 12KH18N9T.
Identifying causes of defects in bearings used in agricultural machines
Authors: Semev K.M. , Kipriyanov F.A. , Savinykh P.A. , Medvedeva N.A. , Belozyorova S.V.
Published: July 2019

The paper considers causes of principal defects in thermal treatment of bearings and presents the results of microstructural analysis of samples taken from rejected ball bearing steel. It states the causes of the identified defects and introduces proposals aimed at reducing the incidence of defects in bearing manufacture arising during the thermal treatment.
How diverse can rare species be on the margins of genera distribution?
Authors: Backes Alice , Mäder Geraldo , Turchetto Caroline , Segatto Ana Lúcia , Fregonezi Jeferson N , Bonatto Sandro L , Freitas Loreta B
Published: July 2019

Different genetic patterns have been demonstrated for narrowly distributed taxa, many of them linking rarity to evolutionary history. Quite a few species in young genera are endemics and have several populations that present low variability, sometimes attributed to geographical isolation or dispersion processes. Assessing the genetic diversity and structure of such species may be important for protecting them and understanding their diversification history. In this study, we used microsatellite markers and plastid sequences to characterize the levels of genetic variation and population structure of two endemic and restricted species that grow in isolated areas on the margin of the distribution of their respective genera. Plastid and nuclear diversities were very low and weakly structured in their populations. Evolutionary scenarios for both species are compatible with open-field expansions during the Pleistocene interglacial periods and genetic variability supports founder effects to explain diversification. At present, both species are suffering from habitat loss and changes in the environment can lead these species towards extinction.
Experimental traffic noise attracts birds during the breeding season
Authors: Hennigar Bronwen , Ethier Jeffrey P , Wilson David R
Published: July 2019

Understanding how anthropogenic disturbance affects animal behavior is challenging because observational studies often involve co-occurring disturbances (e.g., noise, lighting, and roadways), and laboratory experiments often lack ecological validity. During the 2016 and 2017 avian breeding seasons, we investigated the effects of anthropogenic noise and light on the singing and spatial behavior of wild birds by independently manipulating the presence of each type of disturbance at 89 sites in an otherwise undisturbed boreal forest in Labrador, Canada. Each treatment was surrounded by an eight-channel microphone array that recorded and localized avian vocalizations throughout the manipulation. We analyzed the effects of noise and light on the timing of the first vocalizations of each species at each array during the dawn chorus, and on the proximity of the vocalizing birds to the disturbance when those songs were produced. We analyzed all species combined, and then conducted separate analyses for the six most common species: boreal chickadee, dark-eyed junco, ruby-crowned kinglet, Swainson’s thrush, white-throated sparrow, and yellow-rumped warbler. When all species were analyzed together, we found that traffic noise attracted vocalizing birds. There was some evidence that light repelled birds, but this evidence was inconsistent. In our species-specific analyses, yellow-rumped warbler sang earlier in response to noise; Swainson’s thrush was attracted to noise and the combination of noise and light but repelled by light alone. Our study provides some of the first experimental evidence of the independent and combined effects of traffic noise and light on the vocal and spatial behavior of wild birds and suggests that breeding birds may be attracted to noisy roads where they could be exposed to additional forms of disturbance.
Social Trust in the Middle East and North Africa: The Context-Dependent Impact of Citizens’ Socio-Economic and Religious Characteristics
Authors: Spierings Niels
Published: July 2019

Our knowledge of social trust's drivers in the MENA region is limited and there are good reasons to expect that theories based on Western countries cannot be copied to the MENA one-to-one. Arguing for a broader and at the same time context-sensitive comparative approach, I translate the ‘societal winners’, social capital, and religious beliefs mechanisms explaining trust to the MENA context. Moreover, I acknowledge intraregional diversity and test how the impact of these factors also differs among MENA countries. Empirically, I synchronize 47 surveys from 15 MENA countries, which provides the broadest and most systematic assessment of trust in the MENA to date. The results show that the societal-winner mechanism does not hold: employed, higher education and wealthier citizens are not more trusting. However, higher-educated citizens distrust other citizens more, particularly in the strongest autocracies. Religiosity seems pivotal too. Among others, service-attending citizens are more trusting, mainly where regimes regulate religious affairs. Overall, this study provides insight into what shapes generalized social trust in the Middle East and North Africa and it underscores that at a comparative level we need to consider inter-regional and intra-regional forms of context-dependency were we to formulate a broadly applicable theoretical framework of trust's drivers.
Attenuated apoptotic BAX expression as a xenobiotic reporter inSaccharomyces cerevisiae
Authors: Keniya Mikhail V , Monk Brian C
Published: July 2019

Fungal infections are a major challenge to medicine and agriculture. Repeated and prophylactic use of antifungals can lead to pathogen cross-resistance to different classes of drugs. The early development of multidrug resistance in pathogenic fungi includes drug tolerance mediated by drug-dependent activation of drug efflux. In Saccharomyces cerevisiae and the fungal pathogen Candida glabrata, xenobiotic sensing motifs in transcription factors upregulate expression of several ATP-binding cassette (ABC) drug efflux pumps. We have therefore considered how drug candidates that trigger or prevent drug resistance could be identified and evaluated during drug discovery. We report a robust and sensitive, S. cerevisiae-based xenobiotic sensing system using the Pdr1 protein as a sensor and an attenuated version of the apoptotic murine BCL2-associated X (BAX) gene as a reporter. A molecular mechanism of attenuation that involves frameshift reversal may be associated with translation coupling and requires further investigation.
Genome-Wide Genotype-Expression Relationships Reveal Both Copy Number and Single Nucleotide Differentiation Contribute to Differential Gene Expression between Stickleback Ecotypes
Authors: Huang Yun , Feulner Philine G D , Eizaguirre Christophe , Lenz Tobias L , Bornberg-Bauer Erich , Milinski Manfred , Reusch Thorsten B H , Chain Frédéric J J
Published: July 2019

Repeated and independent emergence of trait divergence that matches habitat differences is a sign of parallel evolution by natural selection. Yet, the molecular underpinnings that are targeted by adaptive evolution often remain elusive. We investigate this question by combining genome-wide analyses of copy number variants (CNVs), single nucleotide polymorphisms (SNPs), and gene expression across four pairs of lake and river populations of the three-spined stickleback (Gasterosteus aculeatus). We tested whether CNVs that span entire genes and SNPs occurring in putative cis-regulatory regions contribute to gene expression differences between sticklebacks from lake and river origins. We found 135 gene CNVs that showed a significant positive association between gene copy number and gene expression, suggesting that CNVs result in dosage effects that can fuel phenotypic variation and serve as substrates for habitat-specific selection. Copy number differentiation between lake and river sticklebacks also contributed to expression differences of two immune-related genes in immune tissues, cathepsin A and GIMAP7. In addition, we identified SNPs in cis-regulatory regions (eSNPs) associated with the expression of 1,865 genes, including one eSNP upstream of a carboxypeptidase gene where both the SNP alleles differentiated and the gene was differentially expressed between lake and river populations. Our study highlights two types of mutations as important sources of genetic variation involved in the evolution of gene expression and in potentially facilitating repeated adaptation to novel environments.
Genome Resequencing Reveals Congenital Causes of Embryo and Nestling Death in Crested Ibis (Nipponia nippon)
Authors: Fu Chun-Zheng , Guang Xuan-Min , Wan Qiu-Hong , Fang Sheng-Guo
Published: July 2019

The crested ibis (Nipponia nippon) is endangered worldwide. Although a series of conservation measures have markedly increased the population size and distribution area of these birds, the high mortality of embryos and nestlings considerably decreases the survival potential of this bird species. High-throughput sequencing technology was utilized to compare whole genomes between ten samples from dead crested ibises (including six dead embryos and four dead nestlings aged 0–45 days) and 32 samples from living birds. The results indicated that the dead samples all shared the genetic background of a specific ancestral subpopulation. Furthermore, the dead individuals were less genetically diverse and suffered higher degrees of inbreeding compared with these measures in live birds. Several candidate genes (KLHL3, SETDB2, TNNT2, PKP1, AK1, and EXOSC3) associated with detrimental diseases were identified in the genomic regions that differed between the alive and dead samples, which are likely responsible for the death of embryos and nestlings. In addition, in these regions, we also found several genes involved in the protein catabolic process (UBE4A and LONP1), lipid metabolism (ACOT1), glycan biosynthesis and metabolism (HYAL1 and HYAL4), and the immune system (JAM2) that are likely to promote the normal development of embryos and nestlings. The aberrant conditions of these genes and biological processes may contribute to the death of embryos and nestlings. Our data identify congenital factors underlying the death of embryos and nestlings at the whole genome level, which may be useful toward informing more effective conservation efforts for this bird species.
Phenotypic and Genomic Local Adaptation across Latitude and Altitude in Populus trichocarpa
Authors: Zhang Man , Suren Haktan , Holliday Jason A
Published: July 2019

Local adaptation to climate allows plants to cope with temporally and spatially heterogeneous environments, and parallel phenotypic clines provide a natural experiment to uncover the genomic architecture of adaptation. Though extensive effort has been made to investigate the genomic basis of local adaptation to climate across the latitudinal range of tree species, less is known for altitudinal clines. We used exome capture to genotype 451 Populus trichocarpa genotypes across altitudinal and latitudinal gradients spanning the natural species range, and phenotyped these trees for a variety of adaptive traits in two common gardens. We observed clinal variation in phenotypic traits across the two transects, which indicates climate-driven selection, and coupled gene-based genotype–phenotype and genotype–environment association scans to identify imprints of climatic adaptation on the genome. Although many of the phenotype- and climate-associated genes were unique to one transect, we found evidence of parallelism between latitude and altitude, as well as significant convergence when we compared our outlier genes with those putatively involved in climatic adaptation in two gymnosperm species. These results suggest that not only genomic constraint during adaptation to similar environmental gradients in poplar but also different environmental contexts, spatial scale, and perhaps redundant function among potentially adaptive genes and polymorphisms lead to divergent adaptive architectures.
Upper mantle shear velocity structure beneath the equatorial East Pacific Rise from array-based teleseismic surface-wave dispersion analysis
Authors: Zhai Qiushi , Yao Huajian , Peng Zhigang
Published: July 2019

The Discovery/Gofar transform faults system is associated with a fast-spreading center on the equatorial East Pacific Rise. Most previous studies focus on its regular seismic cycle and crustal fault zone structure, but the characteristics of the upper mantle structure beneath this mid-ocean ridge system are not well known. Here we invert upper mantle shear velocity structure in this region using both teleseismic surface waves and ambient seismic noise from 24 ocean bottom seismometers (OBSs) deployed in this region in 2008. We develop an array analysis method with multi-dimensional stacking and tracing to determine the average fundamental mode Rayleigh wave phase-velocity dispersion curve (period band 20–100 s) for 94 teleseismic events distributed along the E-W array direction. Then, we combine with the previously measured Rayleigh wave phase-velocity dispersion (period band 2–25 s) from ambient seismic noise to obtain the average fundamental mode (period band 2–100 s) and the first-higher mode (period band 3–7 s) Rayleigh wave phase-velocity dispersion. The average dispersion data are inverted for the 1-D average shear wave velocity (Vs) structure from crust to 200-km depth in the upper mantle beneath our study region. The average Vs between the Moho and 200-km depth of the final model is about 4.18 km/s. There exists an ∼5-km thickness high-velocity lid (LID) beneath the Moho with the maximum Vs of 4.37 km/s. Below the LID, the Vs of a pronounced low-velocity zone (LVZ) in the uppermost mantle (15–60 km depth) is 4.03–4.23 km/s (∼10 per cent lower than the global average). This pronounced LVZ is thinner and shallower than the LVZs beneath other oceanic areas with older lithospheric ages. We infer that partial melting (0.5–5 per cent) mainly occurs in the shallow upper mantle zone beneath this young (0–2 Myr) oceanic region. In the deeper portion (60–200 km depth), the Vs of a weak LVZ is 4.15–4.27 km/s (∼5 per cent lower than the global average). Furthermore, the inferred lithosphere-asthenosphere boundary (LAB) with ∼15-km thickness can fit well with the conductive cooling model. These results are useful for understanding the depth distribution and melting characteristics of the upper mantle lithosphere and asthenosphere in this active ridge-transform fault region.
Data-oriented constraint on the interpretation of S receiver function and its application to observations of seismic discontinuities in the lithosphere–asthenosphere system
Authors: Shen Xuzhang , Kim YoungHee , Song Teh-Ru Alex , Lim Hobin
Published: July 2019

This paper aims to improve the robustness of interpretation in the S receiver function (SRF), a technique commonly used to retrieve forward scattering of S-to-P converted waves (Sdp) originated from the lithosphere–asthenosphere system (LAS) beneath the stations. Although the SRF does not suffer interferences from backward scattering waves such as the first multiples from the Moho, one major drawback in the method is that Sdp phases can interfere with P coda waves and it is conceivable that these signal-generated noise may be misinterpreted as Sdp phase from the LAS beneath seismic stations. Through systematic analysis of full-waveform synthetics and SRFs from catalogued source parameters, we find that the strong P coda waves before the S wave in the longitudinal-component waveforms result in unwanted signal-generated noise before the S wave in the synthetic SRFs. If the mean amplitude of SRFs after the S wave is large, dubious signal-generated noise before the S arrival are strong as well. In this study, we honor the level of these unwanted signal-generated noise and devise data-oriented screening criteria to minimize the interference between P coda waves and genuine S-to-P converted waves. The first criterion is LQR, a direct measure of the amplitude ratio between longitudinal P coda waves and radial S wave in the waveform data. The second criterion is AMP, the amplitude of SRFs after the S arrival. We illustrate that these criteria effectively measure the energy level of mantle waves such as the SP wave. With synthetics and real data, we demonstrate the effectiveness of LQR and AMP criteria in minimizing these unwanted signal-generated noise in the stacked SRFs down to 1–2 per cent, improving detection threshold and interpretation of Sdp phases from seismic discontinuities in the LAS.