bluuebunny/crossref_metadata_2025 huggingface dataset:
Design and Research of Dynamic Stiffness Test System for Rubber Shock Absorber Based on LabVIEW
Authors: Zhang Dasen , Chu Jian
Published: September 2019

Rubber shock absorbers are an indispensable component in the fields of ships, automobiles, trains, airplanes and construction engineering. The dynamic stiffness value is an important indicator to measure the performance of rubber shock absorbers. Some existing dynamic stiffness testing methods are often difficult to meet the production enterprises and testing requirements of the testing unit. According to the testing requirements of rubber dynamic characteristics and the development of dynamic stiffness testing technology for rubber shock absorber at home and abroad, designing and developing a new type of rubber vibration damper dynamic stiffness testing technology. Through the USB6008 data acquisition card establishing the connection between the collected data and the data analysis platform based on LabVIEW software, realizing the real-time, accurate and efficient measurement of the rubber shock absorber.
Air Combat Situation Assessment Based on Improved RS Theory
Authors: Ji Huiming , Han Qisong , Yu Minjian , Li Xuyu , Zhang Zhenxing
Published: September 2019

In order to improve the ability of the extraction and weight distribution of key air combat factors in air combat situation assessment, this paper improves the rough set theory and establishes an improved rough set theory air combat situation assessment model. Firstly, the air combat information is discretized and decoupled. Then, the improved rough set theory is used to reduce and assign the attributes, and the air combat situation is calculated and evaluated. Finally, the effectiveness of the model is verified by simulation.
A Multi-strategy Shuffled Frog-leaping Algorithm for Numerical Optimization
Authors: Tang Kezong , Zhan Tangsen , Li Zuoyong
Published: September 2019

This study proposes a multi-strategy shuffled frog-leaping algorithm for numerical optimization (MSSFLA), which combines the merits of a frog-leaping step rule, the crossover operator, and a novel recursive programming. First, the frog-leaping step rule depends on the level of attractive effect between the worst frog and other frogs in a memeplex, which utilizes the advantages of frogs around the worst frog, making the worst frog more conducive to the evolution direction of the whole population. Second, the crossover operator of the genetic algorithm is used for yielding new frogs based on the best and worst individual frog instead of the random mechanism in the original shuffled frog-leaping algorithm (SFLA). The crossover operation aims to enhance population diversity and conduciveness to the memetic evolution of each memeplex. Finally, recursive programming is presented to store the results of preceding attempts as basis for the computation of those that succeed, which will help save a large number of repeated computing resources in a local search. Experiment results show that MSSFLA has better performance than other algorithms on the convergence and searching effectivity. Therefore, it can be considered as a more competitive improved algorithm for SFLA on the efficiency and accuracy of the best solution.
Psychophysics of Consumer’s Sequence Preference of E-commerce Loan Repayments
Authors: Lu Yang , Li Yaning
Published: September 2019

As E-commerce shopping has been growing rapidly in China, many consumers use loans to make a purchase, and then payoff the loan by installments. Recently studies show that all amortizing loans can be viewed a sequence of payments, and consumers prefer a decreasing sequence for a car loan. In this paper, we investigated consumers’ preference of payment sequence for a less valued online purchased commodity, a smart phone. Results show consumers prefer constant sequence over decreasing sequence, indicating that consumers have unique perception of sequence for a smaller amount and shorter term loan, and they may choose constant sequence for convenience. E-commerce credit provider shall stick with the constant repayment plan.
Optimization of Radiation Model of Infrared Decoy with Neural Network
Authors: Zhou Guanwu
Published: September 2019

In this paper, a numerical model is proposed to calculate the infrared radiation characteristics based on the solution of radioactive transport. However, due to the demand of the real-time, a method with back-propagation neural network (BPNN) is developed to optimize the proposed model. The results of simulation experiments show that BPNN possesses good prediction accuracy, and can make the numerical model achieve the real-time requirement.
Construction of Cloud Platform for Mining Group Operation
Authors: Wang Hao , Hu Nailian , Li Guoqing , Hou Jie , Huang Shuwei
Published: September 2019

The operation important for mining group management. The traditional operation is complicated and inefficient for many reasons. Information technologies such as cloud computing, big data, and business intelligence, are inevitable requirements for the quality and efficiency of the mining group. In this study, a cloud platform structure for mining group operation was established with virtualization resource layer, cloud computing platform layer, and service access layer. Then the business logic on cloud platform was designed by using business model, computing logic, business intelligence tools, mathematical model and analysis method, which consists of distributed data acquisition, multidimensional data processing and storage, and business intelligence oriented analysis and decision-making. Finally, a case study was taken out at a large mining group which significantly increases the efficiency of management. The study suggests that Cloud Platform for Mining Group Operation can greatly improve the efficiency of information circulation and provide reliable decision support.
Identifying Users Based on Time-Frequency Characteristics
Authors: Gao Yaqiong , Chen Wanghu , Yang Bo , Mu Yuxiang , Li Jing
Published: September 2019

With the rapid development of information technology, whether it is with regard to the personalized recommendation of the business or network warning by the public security organ, the identification of online users is a very important research topic. The user’s web browsing behavior data contains potential behavioral characteristics, in this paper, we utilize the time-frequency analysis method, which extracts the behavior characteristics when users accessing the network, so as to obtain the user behavior pattern and calculate the similarity between the behavior patterns for achieving the purpose of user identification. This method is verified by the weblog, and the experiment results show that the method extracts user network behavior features based on time-frequency analysis to ensure the accuracy of user identification.
AGRP and ESPL1 as Biomarkers of Brain-Metastasis in Lung Adenocarcinoma
Authors: Deng Jianzhi , Cheng Xiaohui , Zhou Yuehan
Published: September 2019

In the mortal diseases, lung cancer, approximately one fifth of lung adenocarcinoma(LUAD) patients are associated with brain metastasis(BM). And even some patients die of BM. In the present research, the 22753 genes data of 273 primary LUAD or BM samples were downloaded from gene expression omnibus(GEO) datasets. The 145 common differentially expressed genes(DEGs) both from GPL96 and GPL570 platform profiles were screened out by R package. Gene ontology(GO), pathway and protein protein interaction(PPI) network analysis of the DEGs was enriched by online tools. The 14 up- and 131 down-regulated genes were enriched in 18 GO terms and 147 signal pathway. Protein expression of AGRP and ESPL1 is lower in lung cancer than many other cancers. And the km-plots of lung cancer survival curves are also shown that AGRP and ESPL1 express higher in high risk groups. From the research in this paper, we can believe that AGRP and ESPL1 might be the biomarkers for the diagnostic clue of BM from LUAD.
Design of Air Combat Deduction System Based on UML Language
Authors: Ji Huiming , Han Qisong , Yu Minjian , Ding Haiyang
Published: September 2019

According to the characteristics of high cost and great difficulty in air combat exercise, relying on information equipment, this paper designs an air combat deduction model system. Firstly, the system is designed with the idea of ‘Human input, system deducts automatically’, and the key modules of the system are designed. Then the radar search model, missile motion model and the airborne fire control system model are established. Finally, the static model, dynamic model and data flow direction of the system are designed respectively by selecting system use case diagram, sequence diagram and coordination diagram, and the overall model of the system is built based on UML language.
Wavelet-transform Algorithm Application in Hybrid Power System Optimization of Electric Vehicles
Authors: Zhang Yulong , Yang Shichun , Zhou Sida , Chen Fei
Published: September 2019

In order to reduce the changing times of battery’s output power loads and currents, a novel energy management strategy was developed for hybrid power system including a battery pack and an ultracapacitor (UC) pack. The strategy is utilizing wavelet-transform algorithm to allocate power components with different frequency contents among the on-board energy sources. The models of hybrid power system were developed and simulated in MATLAB/Simulink. Simulation results show that: Compared with the logic threshold strategy, the wavelet control method can avoid battery to receive chaotic high-frequency components more effectively. Meantime, the utilization of ultra-capacitor can be improved. Thus battery can be protected and the efficiency of electric vehicles can be increased.
Research on Calibration of Optical See-Through Head-Mounted Display
Authors: Yu Hailong , Liu Guozhong
Published: September 2019

In order to successfully apply augmented reality technology and provide users with immersive 3D experience of augmented reality, it is necessary to calibrate the optical see-through head-mounted display (OST HMD) of augmented reality equipment. With the help of the video tracking system, a new display calibration method was proposed, in which the data of the video tracker were taken as input and the 3d coordinates of the visual virtual model were taken as output to find the projection transformation matrix between the 3d coordinates of the virtual space and the 3d coordinates of the real space. In addition, in order to obtain the video tracker data conveniently, the 3d calibration target with checkerboard was designed. The display calibration experiment was carried out on Microsoft Hololens platform. The experimental results show that the displacement error of the reprojection of the virtual object is 2.7cm within the active range of 80cm*80cm*100cm of the tracker.
Role of monsoon interannual variability on the climate model prediction of seasonal rainfall over Indonesia
Authors: Suaydhi
Published: September 2019

Hindcast produced by a model used in a numerical model-based seasonal prediction system is an essential part of the operational seasonal prediction system. This paper is aimed at evaluating the performance of POAMA and CFSv2 models in predicting the interannual variability of seasonal rainfall over Indonesia. The data used in this research are obtained from POAMA m24 model and CFSv2 model. A seasonal empirical orthogonal function analysis is used for examining the year-to-year variation of seasonal rainfall. The results reveal the influence of ENSO on seasonal rainfall over Indonesia. These results are well simulated by both models, although there is a decrease in the accuracy of the models for longer lead-time. The areal average may suggest that POAMA m24 model with a resolution of T24 has better accuracy for longer lead time, but CFSv2 with a resolution of T126 is superior in simulating the spatial pattern of rainfall over Indonesia.
Estimation of intrinsic vulnerability of shallow groundwater in Jombang District, Jombang Regency, East Java, Indonesia based on Aquifer Vulnerability Index
Authors: Siswoyo H , Azhar R F
Published: September 2019

The level of safety of groundwater to pollution hazards can be identified based on the level of vulnerability of the groundwater to pollution. Determination of groundwater vulnerability intrinsically can be done by using the Aquifer Vulnerability Index (AVI) method based on two physical parameters i.e. the thickness of each layer above the uppermost of saturated aquifer surface and the estimated hydraulic conductivity of each of these sedimentary layers. The objective of this study was to determine the level of groundwater vulnerability intrinsically based on the vulnerability index value of aquifers by using the AVI method. This study was conducted based on sample of 25 dug wells scattered in the Jombang District of Jombang Regency, East Java, Indonesia. Based on the results of the analysis using the AVI method, it can be stated that the hydraulic resistance logarithm in the study area were found to be in the range from -5.22 to 3.84 with the intrinsic vulnerability of groundwater to pollution hazards from extremely high to low.
The implementation of connecting, organizing, reflecting, extending to improve mathematics connection grade 11 science student at one of Christian Senior High School in Rantepao
Authors: Virginiawaty K K , Saragih M J
Published: September 2019

Someone with mathematical connection skills can have a deep understanding of mathematics and have a complete view of mathematics without being separated. From the observations, it was found that the mathematical connections of the grade 11 science students in one of the Christian high schools in Rantepao were still low, where all students could not solve the problem with the mathematical connection indicator beyond the minimum score that already given by the school. This study aims to determine whether or not the CORE model can improve students’ mathematical connections. The data sources used are student test sheets, mentor checklist sheets, student reflection journals, and researcher reflection journals. The research method used by researchers is classroom action research according to Pelton. The results showed an increase in students’ mathematical connections with the application of the Connecting, Organizing, Reflecting, Extending models of XI IPA students at one of the Christian High Schools in Rantepao.
Clarification and encapsulation of Stevia rebaudiana Bertoni water extract
Authors: Martono Y , Pranawati F E R , Riyanto C A , Muninggar J
Published: September 2019

This study is carried out for clarification and encapsulation of water extract from Stevia rebaudiana Bertoni. Clarification was performed using adsorption method of acid activated kaolin. Encapsulation of S. rebaudiana extract was carried out using spray drying method. Product evaluation was performed based on concentration of stevioside and rebaudioside A, moisture content, hygroscopicity, and sensory. The content of stevioside and rebaudiosida A was determined by HPLC. Clarification of S. rebaudiana water extract by using acid activated kaolin was successfully reduce 95% green pigment and 65% yellow pigment. The content of stevioside and rebaudioside A in the optimal encapsulation products is 0.83% and 2.25%, respectively. Water content and hygroscopicity of sweetening products obtained were 9.8% and 12.91%, respectively. Sweetener products still have a lower level of sweetness based on organoleptic test results.
Determination of glucose concentration in aqueous solution using FT NIR spectroscopy
Authors: Rondonuwu F S , Setiawan A , Karwur F F
Published: September 2019

NIR spectroscopy is widely used due to its capability to measure a large number of solid and liquid samples, including water-soluble constituents. The measurements of glucose concentrations in aqueous solutions are useful to examine how low concentrations of glucose in water can be measured using near-infrared spectroscopy and its potential applications for non-invasive measurements of glucose level in the blood. This paper describes an alternative approach to the determination of glucose content in aqueous solutions below 1000 mg/dL using Fourier transform near-infrared spectroscopy. This technique has the advantage of being less intensive sample preparation and non-destructive. Glucose in aqueous solutions were carefully prepared with concentrations of 0 - 100 mg/dL at intervals of 5 mg/dL, 110 - 500 mg/dL at intervals of 10 mg/dL and 525 - 1000 mg/dL at intervals of 25 mg/dL. Thus, the total produces 81 samples of standard solutions for both calibration and validation sample sets. PLSR analysis to near-infrared spectra show that glucose content in aqueous solutions can be predicted accurately with a maximum deviation of 6 mg/dL, indicating that the near-infrared prediction model is sufficient to determine glucose content in the aqueous solutions below 1000 mg/dL. The ability of the NIR to detect glucose content below 1000 mg/dL is particularly important when designing a non-destructive glucose level measuring device using a near-infrared light source.
Physical and Mechanical Properties of Concrete Containing Green Mussel (Perna viridis) Shell Ash as an Admixture
Authors: Nabilah Ismail Nurul , Hazurina Othman Nor , Wan Inn Goh , Shabery Sainudin Muhammad
Published: September 2019

In line with the aim of applying green technology in construction for a sustainable living and environmental preservation, this study focused on the utilization of green mussel shells, which come from unmanaged aquaculture residues. The shell ashes is used as an admixture material in the concrete mix. Green mussel shell, which had undergone drying, crushing, grinding and sieving processes were added into the concrete mix at different percentages of 1%, 2%, 3% and 4%. The concrete specimens were water-cured for 7, 28 and 60 days with the target strength of 30MPa in the 28 days. This research also focused on material characterization in term of physical properties of the mussel shell ash. The physical properties of the mussel shell ash were determine by the specific gravity test, setting time analysis and the particle size distribution. Furthermore, workability of the wet concrete was verified by conducting the slump test. Testing of the compressive strength, tensile strength, and capillary absorption have been conducted on the hardened concrete that contained the mussel shell ash mix right after the 7, 28, and 60 curing days. The high calcium carbonate (CaCO3) content in the mussel shell served as filler within the pores of the hardened concrete. Furthermore, the concrete specimens containing the mussel shell ash (GMSA2) demonstrated higher compressive strengths when compared to the control specimens. Apart from supporting the sustainability concept, this research also concluded that the addition of the mussel shell ash has improved the mechanical properties of the hardened concrete.
Analysis of cycloid type vacuum compressors for water vapor compression systems at sub-atmospheric pressures
Authors: Moesch T W , Janitschke T , Thomas C , Hesse U
Published: September 2019

Current refrigerant regulations lead to a transition towards low GWP refrigerants and natural refrigerants. Water vapor (R718) has been introduced in different vapor compression chiller and heat pump systems. Current R718 systems are based on turbo type compressors due to the resulting sub-atmospheric operating pressure and the low volumetric cooling capacity. This leads to a rather limited application range due to the pressure ratio limitations of turbo compressors. The application range of R718 may be extended towards heat pump operation by using positive displacement compressors such as state of the art vacuum compressors. This paper analyses the application of an oil free cycloid type variable pitch screw vacuum compressor for a heat pump at 2…15 °C evaporation temperature and 25…85 °C condensing temperature. A chamber model was used for the compressor analysis. During the analysis the compressor geometry, its speed and leakage gap sizes were varied. The results include the compressor isentropic efficiency, its volumetric efficiency and the resulting discharge temperature.
Development and Design of Energy Efficient Oil-Flooded Screw Compressors
Authors: Abdan S , Basha N , Kovacevic A , Stosic N , Birari A , Asati N
Published: September 2019

It is estimated that about 17% of the world’s generated power is used for compression. Thus all, even minor improvement of the efficiency of compressors will substantially reduce CO2 emission. This paper presents development of family of energy efficient oil-flooded screw compressors for Kirloskar Pneumatic Company Ltd. The developmental techniques adopted to improve efficiency such as introduction of superior ‘N’ rotor profile, rotor clearance management, performance calculation using 3D CCM (Computational Continuum Mechanics), direct parametric interface to CAD (Computer Aided Design), which contains bearing selection for complete 3D solid modelling. Also, contemporary prototyping and experimental investigation is supported by the fully computerised data acquisition and processing. The cumulative improvement of all these elements of the design process resulted in a very efficient machine which guarantees the competitive position of Kirloskar Pneumatic Company Limited in the screw compressor market.
Improving start up performance of single speed compressors by stator winding design
Authors: Cetinturk Tugba
Published: September 2019

Some east countries have line voltage fluctuations and voltage drops which can cause cooling problems on refrigerators because compressors cannot start up at these low line voltages. That’s why not only COP, but also start up performance at low voltages is critical on single speed compressors. Torque-speed curves of single speed asynchronous motors are so critical for compressor start up performance which takes form by motor design. Depending on compressor mechanical efficiency and shaft power needed, the asynchronous motor winding design should be fine-tuned and torque speed curve should be adjusted for start up properly at low voltage values. Even when the start torque at 0 rpm and breakdown torque values are high enough to provide low voltage compressor starting, instant torque decreases along the curve negatively effects start up performance. This study analyses torque-speed curve characteristics of asynchronous motors and determines stator winding design methods to improve compressor start up performance. The findings are also validated with motor and compressor test results.
Investigation of Discharge Flow and Force Coefficients in Hermetic Reciprocating Compressors
Authors: Sahin Caglar , Kerpicci Hμsnμ , Yasin Karabay Ahmet , Karahan Kerem
Published: September 2019

Low energy consuming products are eternal target of all household appliance manufacturers. To acquire desired energy index, high efficiency variable capacity compressors have started to be used widely on refrigerators. Reed valves and valve plate designs are the most critical issues in the development of reciprocating compressors in terms of coefficient of performance (COP). The stiffness of the reed valves and the port geometries play an important role on reducing the losses at various speeds and operating conditions. In the last decade, Fluid-Structure Interaction (FSI) method has started to be used in order to investigate valve dynamics. Because of the complexity and high computational cost of FSI method, system simulation tools are still preferred for faster and simpler solutions.

In-house developed simulation tool uses flow and force coefficients to calculate valve dynamics and mass flow rate. Those are calculated with the Computational Fluid Dynamics (CFD) analyses with respect to the valve lift. In the present study, flow and force coefficients at different piston positions were investigated. Piston pin which is used to reduce dead volume was also considered as a parameter. CFD calculations were established for steady state conditions at different valve positions with Ansys Fluent. The calculated flow and force coefficients were implemented into the simulation tool and the effect of piston position was presented in terms of COP, cooling capacity and compared with the experimental results.
Wavy plates as impinging oil separating structure at compressor discharge
Authors: Xu Jiu , Hrnjak Pega
Published: September 2019

Oil separation is commonly needed in air conditioning and refrigeration systems to reduce the oil circulation rate and keep the oil inside the compressor. For compactness, the oil separation structure integrated into the compressor is more and more popular than traditional external oil separators. This paper presents the impinging separation mechanism, one of the basic mechanisms of droplet separation. As a representative of the impinging separator, wave-plates structures are studied by flow visualization and experimental measurement under realistic compressor discharge conditions. The video of oil mist flowing through the baffles and plates is captured by a high-speed camera and analyzed quantitatively. The effect of the oil flow condition and the effect of separator geometry design are investigated based on the experimental data. With the help of flow visualization, the flow details are analyzed.
Experimental characteristic simulation for two-stage pipeline centrifugal compressor
Authors: Borovkov A I , Voinov I B , Galerkin Yu B , Drozdov A A , Soldatova K V
Published: September 2019

Up to now, the design methods for centrifugal compressors have been based on results of physical experiments. The possibility of correct CFD calculation of centrifugal compressors gas-dynamic characteristics could fundamentally change the situation. Gas-dynamic projects will become more reliable, cheaper, and the performance of compressors will be improved. However, the problem has not been solved yet. The experience of various authors shows that CFD calculations in many cases do not align well with experimentally obtained data. The aim of this paper is to check whether the commercial CFD software is capable of simulating centrifugal compressor characteristics using a 16 MW pipeline two-stage compressor as an example. The calculated characteristics of pressure ratio, efficiency and head coefficient are compared with characteristics measured using the manufacturer test bench on air. The calculations are performed in two ways: in the first case the flow in the impeller-stator gaps is taken into consideration, and in the second one it is not. In the first case, we do not take into account friction losses of the outer surfaces of impeller shrouds and leakage through labyrinth seals. The interface “STAGE” averages the parameters of flow at the impeller outlet and vaneless diffuser inlet. The flow leaving the impeller is averaged in tangential direction. This way of calculation excludes the mixing process of high and low-energy flow zones at the exit of the impeller. The calculated characteristic configurations are similar to the experimental ones, but they are shifted to the area of higher flow rates, and the difference in pressure ratio is out of the limits acceptable for engineering and research. Calculations that take into consideration gap losses underestimate the maximum efficiency by up to 2.5%. The characteristics calculated without gap losses are closer to the experimental characteristics. However, it is hardly possible to use this circumstance as a recommendation for the simulation methodology. The problem needs further investigation.
Implementation of scroll compressors into the Cordier diagram
Authors: Thomas C , Margraf M , Stoeckel C , Klotsche K , Hesse U
Published: September 2019

Selecting the most suitable machine type for a specific compression task is an essential step to ensure a reliable and economical operation of the overall system. For this, the eligibility of a compression principle can be estimated by the enhanced Cordier diagram by Grabow based on only a few input parameters (specific isentropic work, flow rate, speed and characteristic diameter). The working principle of scroll machines is known for more than one century. However, only the improvements in manufacturing processes during the last decades allowed their utilisation and a significantly increasing interest in scrolls in more and more fields of applications can be seen. Unfortunately, the scroll machine has not yet been introduced to the Cordier diagram.

Therefore, this paper shows a method for determining the characteristic key figures for different given scroll geometries. Based on this, it is shown how to implement scroll compressors into the Cordier diagram, i.e. different designs are analysed and the resulting data points are introduced to the diagram.
Friction and leakage analysis of the blocker-type valve designed for a revolving vane expander
Authors: Naseri Ali , Norris Stuart , Subiantoro Alison
Published: September 2019

Friction and leakage are two known issues that contribute to inefficiencies of rotary vane machines, and the Revolving Vane (RV) mechanism was introduced to reduce them. When used as an expander, a mechanism to determine the timing of the suction process in RV machine is required. In this study, a blocker-type valve is proposed for the suction control, and a simulation is carried out to investigate its friction and leakage characteristics. The valve comprises a stationary blocker that blocks high-pressure working fluid from entering the working chambers during expansion. In order to reduce friction, there should be a clearance between the rotary parts and the stationary blocker, which inevitably causes leakage of the working fluid into the working chambers. The leakage was modelled as a compressible flow through a convergent nozzle followed by a Fanno flow through an adiabatic constant cross-section channel. The results showed that the amount of leakage in the absence of lubricants is almost higher than ideal expander flow rate. However, this leakage demonstrated a positive contribution to the output torque as the results of the cylinder wall shear stress. The results suggested the importance of using lubricants in this valve design.
Factors Associated with Establishment and Growth of Pinus coulteri and Pinus sabiniana in California’s Central Coast Bioregion
Authors: Davis Thomas Seth , Redmond Miranda D , Foote Nathaniel E , Miller William
Published: September 2019

Forest inventory indicated recent decline in a P. coulteri population at its northern extent but live stems in sympatric P. sabiniana increased. Patterns of cone production, localized factors associated with regeneration, relations between wildfire and tree age distributions, and correlations between climate, seedling establishment, and tree growth were analyzed as potential mechanisms underlying unequal demographics between the two species. Four findings emerged: (1) P. sabiniana had a higher frequency of open cones at the time of observation, but cone production was size-biased, and cone production rates were similar for both species; (2) P. sabiniana seedlings were associated with a higher proportion of bare ground cover and westerly aspects, whereas establishment of P. coulteri seedlings was correlated with warm growing seasons and high vapor-pressure deficits, and seedlings occurred on northernly aspects; (3) age distributions of stands inside and outside a wildfire perimeter did not differ for either species, but annual growth increments of P. coulteri were greater within the fire perimeter; and (4) P. coulteri was even-aged, establishment was episodic, and occurred approximately 10 years post-wildfire. In contrast, the age distribution of P. sabiniana was highly variable, consistent with continuous recruitment, and establishment was not correlated with a climate signal.
Authoritarian Audiences, Rhetoric, and Propaganda in International Crises: Evidence from China
Authors: Weiss Jessica Chen , Dafoe Allan
Published: September 2019

How do government rhetoric and propaganda affect mass reactions in international crises? Using two scenario-based survey experiments in China, one hypothetical and one that selectively reminds respondents of recent events, we assess how government statements and propaganda impact Chinese citizens’ approval of their government's performance in its territorial and maritime disputes. We find evidence that citizens disapprove more of inaction after explicit threats to use force, suggesting that leaders can face public opinion costs akin to audience costs in an authoritarian setting. However, we also find evidence that citizens approve of bluster—vague and ultimately empty threats—suggesting that talking tough can provide benefits, even in the absence of tough action. In addition, narratives that invoke future success to justify present restraint increase approval, along with frames that emphasize a shared history of injustice at the hands of foreign powers.
2018 Highlights of Urban Entomology
Authors: Gondhalekar Ameya D
Published: September 2019

The field of urban entomology is primarily associated with the study of ants, bed bugs, cockroaches, termites, and other occasional invader pests that are found within or near human-made structures. A wide array of peer-reviewed studies were published in 2018. The topics of these articles ranged from genomes and basic biology of urban insects to various applied aspects of pest management. Key findings of these papers are presented and discussed from the perspective of the contributions they make to the discipline of urban entomology. Additionally, potential future research opportunities that are evident from these publications have been outlined.
Distinct polysaccharide growth profiles of human intestinalPrevotella copriisolates
Authors: Fehlner-Peach Hannah , Magnabosco Cara , Raghavan Varsha , Scher Jose U. , Tett Adrian , Cox Laura M. , Gottsegen Claire , Watters Aaron , Wiltshire-Gordon John D. , Segata Nicola , Bonneau Richard , Littman Dan R.
Published: September 2019

The gut-dwellingPrevotella copri, the most prevalentPrevotellaspecies in human gut, have been associated with diet as well as disease, but our understanding of their diversity and functional roles remains rudimentary, as studies have been limited to 16S and metagenomic surveys and experiments using a single type strain. Here, we describe the genomic diversity of 83P. copriisolates from 11 donors. We demonstrate that genomically distinct isolates, which can be categorized into differentP. copricomplex clades, utilize defined sets of plant polysaccharides that can be predicted in part from their genomes and from metagenomic data. This study thus reveals both genomic and functional differences in polysaccharide utilization between several novel human intestinalP. copristrains.
Perceptual learning of lesions in mammograms induced by response feedback during training
Authors: Frank Sebastian M. , Qi Andrea , Ravasio Daniela , Sasaki Yuka , Rosen Eric , Watanabe Takeo
Published: September 2019

Detecting subtle lesions in mammograms indicative of early breast cancer usually requires years of experience. Well-designed training paradigms could be a strong tool for promoting perceptual learning (PL) with rapid and long-lasting improvement in detectability of these subtle mammographic lesions. Given that PL occurs without feedback about the accuracy of subjects’ responses, the role of feedback has been completely ignored in clinical applications of PL. However, in this study, we found that the contents of the feedback profoundly and differentially influence the formation and retention of PL to detect calcification and architectural distortion lesions, two types of mammographic lesions that are frequently missed in mammographic screenings. We trained subjects to detect one type of lesion in a mammogram and manipulated the content of the response feedback during training for 3 groups (no feedback, correctness only, and both correctness and location of the lesion). We found that PL occurred for both lesions when both correctness and location feedback were provided. PL also occurred for calcifications but not for distortions when only correctness was provided. No learning occurred without feedback for either lesion. A retest conducted six months later showed that PL was retained only in the group with both correctness and location feedback for both types of lesions. In contrast to the general consensus of basic PL studies, our results demonstrate that the content of the response feedback is a determining factor in forming and retaining PL to detect mammographic lesions.
Cis-Regulatory Accessibility Directs Muller Glial Development and Regenerative Capacity
Authors: VandenBosch Leah S. , Wohl Stefanie G. , Wilken Matthew S. , Cox Kristen , Chipman Laura , Reh Thomas A.
Published: September 2019

Diseases and damage to the retina lead to losses in retinal neurons and eventual visual impairment. Although the mammalian retina has no inherent regenerative capabilities, fish have robust regeneration from Müller glia (MG). Recently, we have shown that driving expression of Ascl1 in adult mouse MG stimulates neurogenesis similar to fish regeneration. The regeneration observed in the mouse is limited in the variety of neurons that can be derived from MG; Ascl1-expressing MG primarily generate bipolar cells. To better understand the limits of MG-based regeneration in mouse retinas, we used ATAC- and RNA-seq to compare newborn progenitors with MG. Our analysis demonstrated striking similarities between MG and progenitors, with losses in regulatory motifs for neurogenesis genes. Young MG were found to have intermediate expression profiles and accessible DNA, which is mirrored in the ability of Ascl1 to direct bipolar neurogenesis in young MG. When comparing what makes bipolar and photoreceptor cells distinct from glial cells, we find that bipolar-specific accessible regions are more frequently linked to bHLH motifs and Ascl1 binding, indicating that Ascl1 preferentially binds to bipolar regions. Overall, our analysis indicates a loss of neurogenic gene expression and motif accessibility during glial maturation that may prevent efficient reprogramming.
A putative novel role forEip74EFin male reproduction in promoting sperm elongation at the cost of male fecundity
Authors: Chebbo Sharif , Josway Sarah , Belote John M. , Manier Mollie K.
Published: September 2019

Spermatozoa are the most morphologically variable cell type, yet little is known about genes controlling natural variation in sperm shape.Drosophilafruit flies have the longest sperm known, which are evolving under postcopulatory sexual selection, driven by sperm competition and cryptic female choice. Long sperm outcompete short sperm but primarily when females have a long seminal receptacle (SR), the primary sperm storage organ. Thus, selection on sperm length is mediated by SR length, and the two traits are coevolving across theDrosophilalineage, driven by a genetic correlation and fitness advantage of long sperm and long SR genotypes in both males and females.Ecdysone induced protein 74EF(Eip74EF) is expressed during post-meiotic stages of spermatogenesis, when spermatid elongation occurs, and we found that it is rapidly evolving under positive selection inDrosophila. Hypomorphic knockout of theE74Aisoform leads to shorter sperm but does not affect SR length, suggesting that E74A may be involved in promoting spermatid elongation but is not a genetic driver of male-female coevolution. We also found thatE74Aknockout has opposing effects on fecundity in males and females, with an increase in fecundity for males but a decrease in females, consistent with its documented role in oocyte maturation. Our results suggest a novel function ofEip74EFin spermatogenesis and demonstrates that this gene influences both male and female reproductive success. We speculate on possible roles for E74A in spermatogenesis and male reproductive success.

RESEARCH HIGHLIGHTS

Eip74EFpromotes oocyte maturation inDrosophila. We found evidence that it also promotes sperm elongation in males, but at a cost to male fecundity. Mutant males have shorter sperm but have higher reproductive success, while females have reduced fecundity.
De novo assembly of a Tibetan genome and identification of novel structural variants associated with high altitude adaptation
Authors: Ouzhuluobu  , He Yaoxi , Lou Haiyi , Cui Chaoying , Deng Lian , Gao Yang , Zheng Wangshan , Guo Yongbo , Wang Xiaoji , Ning Zhilin , Li Jun , Li Bin , Bai Caijuan , Baimakangzhuo  , Gonggalanzi  , Dejiquzong  , Bianba  , Duojizhuoma  , Liu Shiming , Wu Tianyi , Xu Shuhua , Qi Xuebin , Su Bing
Published: September 2019

Structural variants (SVs) may play important roles in human adaption to extreme environments such as high altitude but have been under-investigated. Here, combining long-read sequencing with multiple scaffolding techniques, we assembled a high-quality Tibetan genome (ZF1), with a contig N50 length of 24.57 mega-base pairs (Mb) and a scaffold N50 length of 58.80 Mb. The ZF1 assembly filled 80 remaining N-gaps (0.25 Mb in total length) in the reference human genome (GRCh38). Markedly, we detected 17,900 SVs, among which the ZF1-specific SVs are enriched in GTPase activity that is required for activation of the hypoxic pathway. Further population analysis uncovered a 163-bp intronic deletion in the MKL1 gene showing large divergence between highland Tibetans and lowland Han Chinese. This deletion is significantly associated with lower systolic pulmonary arterial pressure, one of the key adaptive physiological traits in Tibetans. Moreover, with the use of the high quality de novo assembly, we observed a much higher rate of genome-wide archaic hominid (Altai Neanderthal and Denisovan) shared non-reference sequences in ZF1 (1.32%-1.53%) compared to other East Asian genomes (0.70%-0.98%), reflecting a unique genomic composition of Tibetans. One such archaic-hominid shared sequence, a 662-bp intronic insertion in the SCUBE2 gene, is enriched and associated with better lung function (the FEV1/FVC ratio) in Tibetans. Collectively, we generated the first high-resolution Tibetan reference genome, and the identified SVs may serve as valuable resources for future evolutionary and medical studies.
MetaLab 2.0 enables accurate post-translational modifications profiling in metaproteomics
Authors: Cheng Kai , Ning Zhibin , Zhang Xu , Li Leyuan , Liao Bo , Mayne Janice , Figeys Daniel
Published: September 2019

Studying the structure and function of microbiomes is an emerging research field. Metaproteomic approaches focusing on the characterization of expressed proteins and post-translational modifications (PTMs) provide a deeper understanding of microbial communities. Previous research has highlighted the value of examining microbiome-wide protein expression in studying the roles of the microbiome in human diseases. Nevertheless, the regulation of protein functions in complex microbiomes remains under-explored. This is mainly due to the lack of efficient bioinformatics tools to identify and quantify PTMs in the microbiome. We have developed a comprehensive software termed MetaLab for the data analysis of metaproteomic datasets. Here we build an open search workflow within MetaLab for unbiased identification and quantification of PTMs from microbiome samples. This bioinformatics platform provides information about proteins, PTMs, taxa, functions, and pathways of microbial communities. The performance of the workflow was evaluated using conventional proteomics, metaproteomics from mouse and human gut microbiomes, and modification-specific enriched datasets. Superior accuracy and sensitivity were obtained simultaneously by using our method comparing with the traditional closed search strategy.
Integrative model to coordinate the oligomerization and aggregation mechanisms of CCL5
Authors: Chen Yi-Chen , Chen Siou-Pei , Li Jin-Ye , Chen Pei-Chun , Lee Yi-Zong , Li Kun-Mou , Zarivach Raz , Sun Yuh-Ju , Sue Shih-Che
Published: September 2019

The CC-type chemokine ligand 5 (CCL5) is involved in the pathogenesis of many inflammatory conditions. The oligomerization and aggregation of CCL5 are considered to be responsible for its inflammatory properties. The CC-type dimer acts as the basic unit to constitute the oligomer. However, the structural basis of CCL5 oligomerization remains controversial. In this study, NMR and biophysical analyses proposed evidence that no single dimer-dimer interaction dominates in the oligomerization process of CCL5. CCL5 could oligomerize alternatively through two different interactions, E66-K25 and E66-R44/K45. In addition, a newly determined trimer structure reported an interfacial interaction through the N-terminal12FAY14sequence. The interaction contributes to aggregation and precipitation. In accordance with the observations, an integrative model explains the CCL5 oligomerization and aggregation process. CCL5 assembly consists of two types of dimer-dimer interactions and one aggregation mechanism. For full-length CCL5, the molecular accumulation triggers oligomerization through the E66-K25 interaction, and the12FAY14interaction acts as a secondary effect to derive aggregation. The E66-R44/K45 interaction dominates in CCL5 N-terminal truncations. The interaction would lead to filament-like formation in solution.
Conjugation of Antibodies to Horseradish Peroxidase
Authors: Berg Eric A. , Fishman Jordan B.
Published: September 2019

Antibodies conjugated with horseradish peroxidase (HRP) are one of the most widely used bioreagents in the biological sciences. This protocol is a basic method for adding HRP to a thiolated antibody and can be adapted for use with different cross-linkers. Conjugation methods usually focus on linking through the lysines on HRP because there are only six of them and their modification does not adversely affect enzyme activity.
Nucleic Acid Platform Technologies
Authors: Rando Oliver
Published: September 2019

Every microarray experiment is based on a common format. First, a large number of nucleotide “spots” are arrayed onto a substrate, typically a glass slide, a silicon chip, or microbeads. Second, a complex population of nucleic acids (isolated from cells, selected from in vitro-synthesized libraries, or obtained from another source) is labeled, typically with fluorescent dyes. Third, the labeled nucleic acids are allowed to hybridize to their complementary spot(s) on the microarray. Fourth, the hybridized microarray is washed, allowing the amount of hybridized label to then be quantified. Analysis of the raw data generates a readout of the levels of each species of RNA in the original complex population. This introduction includes several examples of microarray applications and provides a discussion of the basic steps of most microarray experiments.
Crystal structure of (1S,2R)-2-[(3R,4S)-3-methyl-4-phenyl-1,2,3,4-tetrahydroisoquinolin-2-yl]-1,2-diphenylethanol
Authors: Ben Ali Karim , Retailleau Pascal
Published: September 2019

The synthesis and crystal structure of the title compound, C30H29NO, are described. This compound is a member of the chiral dihydroisoquinoline-derived family, used as building blocks for functional materials and as source of chirality in asymmetric synthesis, and was isolated as one of two diastereomeric β-amino alcohols, the title molecule being found to be the (S,R) diastereoisomer. In the crystal, molecules are packed in a herringbone manner parallel to (103) and (10\overline{3}) via weak C—H...O and C—H...π(ring) interactions. Hirshfeld surface analysis showed that the surface contacts are predominantly H...H interactions (ca 75%). The crystal studied was refined as a two-component inversion twin.