bluuebunny/crossref_metadata_2025 huggingface dataset:
Isotopic evidence for the timing of the dietary shift toward C
4
foods in eastern African
Paranthropus
Authors: Wynn Jonathan G. , Alemseged Zeresenay , Bobe René , Grine Frederick E. , Negash Enquye W. , Sponheimer Matt
Published: August 2020

Significance

Reconstructing the dietary adaptations of our earliest ancestors is critical to understanding the evolution of our relationship with our environment. Here, we present carbon isotope data from hominins of the Shungura and Usno Formations, both part of the Pliocene to Pleistocene Omo Group, Ethiopia, a key sequence for the study of hominin evolution in eastern Africa. Our data show that about 2.37 Ma the diet of both robust and gracile hominins shifted profoundly toward consumption of C
4
-derived foods (largely grasses and sedges), within the temporal range of an early member of the genus
Paranthropus aethiopicus
. This dietary shift in both groups of hominins occurred during a period marked by similar patterns for coeval herbivore taxa.
Intein-mediated cytoplasmic reconstitution of a split toxin enables selective cell ablation in mixed populations and tumor xenografts
Authors: Purde Vedud , Kudryashova Elena , Heisler David B. , Shakya Reena , Kudryashov Dmitri S.
Published: August 2020

Significance

Protein reconstitution via transsplicing by split inteins is an indispensable tool in protein engineering, biotechnology, and experimental therapeutics. In living cells, the application of split inteins has been limited to their nonspecific delivery or expression from genetic elements, which come with substantial limitations in specificity of targeting and temporal control of expression and generation of the transspliced product. To overcome these limitations we designed a protocol for delivering the split-intein protein fragments to the cell cytoplasm via a receptor-specific toxin-based delivery machinery. We achieved a precisely controlled reconstitution of a functional catalytic domain of diphtheria toxin from its two dysfunctional fragments, one expressed and one delivered as a protein, in selective subpopulations of cells in mixed cultures and in vivo.
Metabolic stress promotes stop-codon readthrough and phenotypic heterogeneity
Authors: Zhang Hong , Lyu Zhihui , Fan Yongqiang , Evans Christopher R. , Barber Karl W. , Banerjee Kinshuk , Igoshin Oleg A. , Rinehart Jesse , Ling Jiqiang
Published: August 2020

Significance

Protein synthesis is a fundamental cellular process that occurs from bacteria to humans. Highly accurate protein synthesis has been shown to be critical for the fitness of the cell and is controlled by sophisticated molecular mechanisms. One such mechanism is the release of mature proteins at stop codons to prevent readthrough. Here we identify an environmental stress that substantially increases the level of stop-codon readthrough during protein synthesis in bacteria and provide insights into the underlying mechanism. Intriguingly, the level of readthrough fluctuates extensively among single cells that are genetically identical and grown under the same stress condition. Cells with different levels of readthrough vary in phenotypes, and individual cells with high readthrough recover better from the acid stress.
US racial inequality may be as deadly as COVID-19
Authors: Wrigley-Field Elizabeth
Published: August 2020

The COVID-19 pandemic is causing a catastrophic increase in US mortality. How does the scale of this pandemic compare to another US catastrophe: racial inequality? Using demographic models, I estimate how many excess White deaths would raise US White mortality to the best-ever (lowest) US Black level under alternative, plausible assumptions about the age patterning of excess mortality in 2020. I find that 400,000 excess White deaths would be needed to equal the best mortality ever recorded among Blacks. For White mortality in 2020 to reach levels that Blacks experience outside of pandemics, current COVID-19 mortality levels would need to increase by a factor of nearly 6. Moreover, White life expectancy in 2020 will remain higher than Black life expectancy has ever been unless nearly 700,000 excess White deaths occur. Even amid COVID-19, US White mortality is likely to be less than what US Blacks have experienced every year. I argue that, if Black disadvantage operates every year on the scale of Whites’ experience of COVID-19, then so too should the tools we deploy to fight it. Our imagination should not be limited by how accustomed the United States is to profound racial inequality.
“Feel really Uruguayan”
Authors: Uber Diane R.
Published: August 2020

This chapter considers second-person singular
forms of address (tú, vos, usted) in advertisements and business
documents in the Spanish of Montevideo, Uruguay. Tú is considered
the standard-Spanish familiar address and usted the standard respectful
address, while vos is used as an familiar form of address among
Uruguayans. Norms of politeness dictate that speakers should
accommodate to the hearer using usted. However, familiar vos can
indicate politeness for speakers with a similar social status, or to
show solidarity. Using examples from marketing and advertising to
illustrate usage, we find that over 70% of examples used vos, almost
19% employed usted, and less than 7% used tú. This supports claims
that tuteo (whether verbal or pronominal) is disappearing from
Montevideo.
‘En esta petsa, este anio’
Authors: Chappell Whitney
Published: August 2020

The historical evolution of the Caribbean Coast of
Nicaragua has given rise to a multilingual and multicultural region
that has been, until relatively recently, sheltered from the Spanish
language spoken in Western Nicaragua. As contact has increased
between the country’s East and West, Miskitu residents are
increasingly learning Spanish, but for many it serves as a second or
third language, resulting in a unique sound system. This chapter
explores the phonetic features found in the speech of Miskitu-
dominant Spanish speakers in Bilwi, including the transfer of
Miskitu phones into Spanish and the transformation of variable rules
under transfer. I argue that each individual feature can be found in
other parts of the Spanish-speaking world, but this specific
combination of phonetic features reflects the unique culture and
history of the Miskitu people, highlighting the linguistic outcomes
of social and linguistic isolation and contact along the Caribbean
Coast.
The Correlates of Unfitness to Stand Trial in Victoria, Australia
Authors: Blake Grant Alan , Ogloff James R. P.
Published: August 2020

Understanding the correlates of fitness to stand trial is essential to undertaking efficient, evidence-based assessments. We retrospectively analyzed 248 fitness assessment reports pertaining to 115 defendants in Victoria, Australia. Cognitive disorders (e.g., intellectual disability, brain injury) were the strongest predictor of unfitness whereas psychosis was unrelated. Psychiatrists authored the majority of reports (62.4%). Psychologists spent more time assessing the defendant, wrote longer reports, and reviewed more collateral materials. The reports expressly noted that malingering and feigning were considered in only 19% of reports. Fitness evaluations could be improved with standardized interviews, more consideration of statutory definitions of unfitness legal precedent, and embedding feigned unfitness measures into a general assessment procedure.
Evaluation of ocular and cervical vestibular evoked myogenic potentials in patients with conductive and sensorineural hearing loss
Authors: El Kousht Moustafa , Dessouky Tarek Mohamed E. L. , Koura Rabab Ahmed , ElRahman Manar Abd
Published: August 2020

Background

Vestibular evoked myogenic potential (VEMP) test is an electrophysiological testing that can assess dysfunction of otolithic organs and the integrity of their pathways precisely.

Aim

Compare amplitude and latency of ocular and cervical vestibular evoked myogenic potentials evoked by air- and bone-conducted stimuli in three different groups.

Materials and methods

The control group (group 1) included ten healthy volunteers adults (20 ears) with normal hearing thresholds. Group 2 consisted of ten patients (20 ears) with conductive hearing loss (CHL) and group 3 comprised 10 patients (20 ears) with sensorineural hearing loss (SNHL). All participants underwent pure tone audiometry, immittancemetry ocular vestibular evoked myogenic potential (oVEMPs) and cervical vestibular evoked myogenic potential (cVEMPs) by air and bone conduction stimuli.

Results

The response rate of cVEMPs and oVEMPs elicited by both types of stimuli was 100% in control group and SNHL group. In the group of conductive hearing loss, air conduction(AC) (c VEMPs and o VEMPs) response rate was 60%. There was a statistically significant positive correlation between latencies of oVEMPs and cVEMPs evoked by AC and BC methods and degrees of hearing loss in SNHL group.

Conclusion

Ocular and cervical VEMPs elicited by bone conduction (BC) stimuli aren’t vulnerable to conductive hearing loss. Bc VEMPs provides assessment of vestibular system in patients with conductive hearing loss. Significant correlation was found between cVEMPs and oVEMPs abnormalities and severity of sensorineural hearing loss.
Human cochlear microanatomy – an electron microscopy and super-resolution structured illumination study and review
Authors: Liu Wei , Glueckert Rudolf , Schrott-Fischer Annelies , Rask-Andersen Helge
Published: August 2020

Objective

Studies of the human cochlea are particularly challenging due its exceptional vulnerability and surrounding hard bone. Swift fixation and mild decalcification are necessary to maintain its structural integrity and preserve antigenicity. Such procedures may allow immunohistochemistry, gene analyses, and molecular imaging using super resolution illumination microscopy (SR-SIM) with nanometer resolution.

Design

This presentation updates recent studies of the human cochlear microanatomy and immunohistochemistry by our laboratory, discussed in the context of current and past anatomic findings and the available literature.

Results

Human studies are necessary, and there are intriguing discrepancies compared with experimental animal studies, highlighting that “men are not simply big mice.” The results may improve our understanding of the function of the human hearing organ, the diseases related to it, and how this better understanding can be extended to impact future treatment.

Conclusion

The first human inner ear gene therapy trials are in progress, and the accessibility of human cochlear tissue for future stem cell treatment and gene transfer needs further elucidation.
Can we use next-generation gravitational wave detectors for terrestrial precision measurements of Shapiro delay?
Authors: Sullivan Andrew G , Veske Doğa , Márka Zsuzsa , Bartos Imre , Ballmer Stefan , Shawhan Peter , Márka Szabolcs
Published: August 2020

Shapiro time delay is one of the fundamental tests of general relativity and post-Newtonian theories of gravity. Consequently, its measurements can be used to probe the parameter γ which is related to spacetime curvature produced by a unit mass in the post-Newtonian formalism of gravity. To date all measurements of time delay have been conducted on astronomical scales. It was asserted in 2010 that gravitational wave detectors on Earth could be used to measure Shapiro delay on a terrestrial scale via massive rotating systems. Building on that work, we consider how measurements of Shapiro delay can be made using next-generation gravitational wave detectors. We perform an analysis for measuring Shapiro delay with the next-generation gravitational wave detectors Cosmic Explorer and Einstein Telescope to determine how precisely the effect can be measured. Using a rotating mass unit design, we find that Cosmic Explorer and Einstein Telescope can measure the Shapiro delay signal with amplitude signal to noise ratios upwards of ∼28 and ∼43 in 1 year of integration time, respectively. By measuring Shapiro delay with this technique, next-generation interferometers will allow for terrestrial measurements of γ in the paramaterized post-Newtonian formalism of gravity with sub-percent precision.
Effects of WC-Co reinforced Ni-based alloy by laser melting deposition: Wear resistance and corrosion resistance*
Authors: Huang Zhao-Zhen , Zhang Zhi-Chen , Tantai Fan-Liang , Tian Hong-Fang , Gu Zhen-Jie , Xi Tao , Qian Zhu , Fang Yan
Published: August 2020

WC-Co reinforced C276 alloy composite coatings are fabricated on Q235 steel by laser melting deposition. The microstructure, hardness, wear performance, and electrochemical corrosion behavior of composite coating are studied. The results show that WC-Co particles are mostly uniformly distributed in the coating and provide favorable conditions for heterogeneous nucleation. The microstructure of C276/WC-Co composite coatings is composed of γ-Ni solid solution dendrites and MoNi solid solution eutectics. The WC-Co particles can effectively improve the hardness and wear resistance of C276 alloy. The average hardness of the composite coating containing 10-wt% WC-Co (447 HV0.2) are 1.26 times higher than that of the C276 alloy (356 HV0.2). The wear rate of composite coating containing 10-wt% WC-Co (6.95 × 10−3 mg/m) is just 3.5% of that of C276 coating (196.23 × 10−3 mg/m). However, comparing with Hastelloy C276, the corrosion resistance of C276/WC-Co composite coating decreases.
Ultra wide sensing range plasmonic refractive index sensor based on nano-array with rhombus particles*
Authors: Zhu Jiankai , Wang Xiangxian , Wu Xiaoxiong , Su Yingwen , Xu Yueqi , Qi Yunping , Zhang Liping , Yang Hua
Published: August 2020

We propose a two-dimensional metal grating with rhombus particles on a gold film structure for refractive index sensing due to its perfect absorption at near-infrared wavelength. Via two-dimensional metal grating coupling, the incident light energy is effectively transformed into the surface plasmons which propagate along the upper surface of the gold film and interact with the surrounding environment in a wide range. The plasmonic resonance mechanism of the structure is discussed in detail by theoretical analysis and finite-difference time-domain method. After optimizing the geometrical parameters, the designed structure shows the sensing performance with a refractive index sensitivity of 1006 nm/RIU. More importantly, this plasmonic refractive index sensor achieves an ultra wide refractive index sensing range from 1.0 to 2.4 with a stable sensing performance. The promising simulation results of the structure show that the sensor has a broad application prospect in the field of biology and chemistry.
Calculation of radiative heat flux on irregular boundaries in participating media*
Authors: Sun Yu-Jia , Zheng Shu
Published: August 2020

Radiative heat flux at wall boundaries is important for its thermal design. Numerical methods based on structured grids are becoming trendy due to their simplicity and efficiency. Existing radiative transfer equation solvers produce oscillating radiative heat flux at the irregular boundary if they are based on structured grids. Reverse Monte Carlo method and analytical discrete ordinates method are adopted to calculate the radiative heat flux at complex boundaries. The results show that the reverse Monte Carlo method can generate a smooth radiative heat flux profile and it is smoother with larger energy bundles. The results from the analytical discrete ordinates method show that the fluctuations are due to the ray effect. For the total or the mean radiative heat flux, the results from the analytical discrete ordinates method are very close to those from the reverse Monte Carlo method.
Monitoring radiation damage in the LHCb Tracker Turicensis
Authors: Beteta C. Abellan , Atzeni M. , Battista V. , Bursche A. , Dey B. , Suarez A. Dosil , Elsasser C. , Prieto A. Fernandez , Fu J. , Graverini E. , Komarov I. , Cid E. Lemos , Lionetto F. , Mauri A. , Merli A. , Pais P.R. , Trigo E. Perez , Regales M. del Pilar Peco , Stefko P. , Steinkamp O. , Storaci B. , Tobin M. , Weiden A.
Published: August 2020

This paper presents the techniques used to monitor radiation damage in the LHCb Tracker Turicensis during the LHC Runs 1 and 2. Bulk leakage currents in the silicon sensors were monitored continuously, while the full depletion voltages of the sensors were estimated at regular intervals by performing dedicated scans of the charge collection efficiency as a function of the applied bias voltage. Predictions of the expected leakage currents and full depletion voltages are extracted from the simulated radiation profile, the luminosity delivered by the LHC, and the thermal history of the silicon sensors. Good agreement between measurements and predictions is found.
Arsenic trioxide-eluting electrospun nanofiber-covered self-expandable metallic stent reduces granulation tissue hyperplasia in rabbit trachea
Authors: Li Yahua , Li Mengde , Wang Xiaofeng , Wang Yuhui , Li Chang , Zhao Yanan , Li Zhaonan , Chen Jianjian , Li Jing , Ren Kewei , Duan Xuhua , Ren Jianzhuang , Han Xinwei , Li Qian
Published: August 2020

Stent-related granulation tissue hyperplasia is a major complication that limits the application of stents in airways. In this study, an arsenic trioxide-eluting electrospun nanofiber-covered self-expandable metallic stent (ATO-NFCS) was developed. Poly-L-lactide-caprolactone (PLCL) was selected as the drug-carrying polymer. Stents with two different ATO contents (0.4% ATO/PLCL and 1.2% ATO/PLCL) were fabricated. The in vitro release in simulated airway fluid suggested that the total ATO release time was 1 d. The growth of human embryonic pulmonary fibroblasts (CCC-HPF-1), normal human bronchial epithelial cells and airway smooth muscle cells was inhibited by ATO. When embedded in paravertebral muscle, the nanofiber membrane showed good short-term and long-term biological effects. In an animal study, placement of the ATO-NFCS in the trachea through a delivery system under fluoroscopy was feasible. The changes in liver and kidney function 1 and 7 d after ATO-NFCS placement were within the normal range. On pathological examination, the heart, liver, spleen, lungs and kidneys were normal. The effectiveness of the ATO-NFCS in reducing granulation tissue hyperplasia and collagen deposition was demonstrated in the rabbit airway (n = 18) at 4 weeks. The present study preliminarily investigated the efficacy of the ATO-NFCS in reducing granulation tissue formation in the trachea of rabbits. The results suggest that the ATO-NFCS is safe in vivo, easy to place, and effective for the suppression of granulation tissue formation.
Multi-year isoscapes of lake water balances across a dynamic northern freshwater delta
Authors: Remmer Casey R , Neary Laura K , Kay Mitchell L , Wolfe Brent B , Hall Roland I
Published: August 2020

Sustainable approaches capable of tracking status, trends and drivers of lake water balances in complex, remote landscapes are needed to inform ecosystem stewardship and water-security actions. At the Peace-Athabasca Delta (Alberta, Canada), a globally recognized freshwater floodplain landscape, concerns about water-level drawdown and multiple potential stressors have prompted need to improve knowledge of lake water balances and establish a lake monitoring program. Yet, the delta’s remoteness and dynamic nature present challenges to these goals. Here we use over 1000 measurements of water isotope composition at ∼60 lakes and 9 river sites during the spring, summer and fall of five consecutive years (2015–2019) to elucidate patterns in lake water balance over time and space, the influential roles of evaporation and river floodwaters, and relations with meteorological conditions and river water levels. Calculation of evaporation-to-inflow ratios using a coupled-isotope tracer approach, displayed via generalized additive models and geospatial ‘isoscapes’, reveal strongly varying lake water balances. Results identify distinct areas vulnerable to lake-level drawdown, given the likelihood of continued decline in ice-jam flood frequency, longer ice-free season duration and reduced snowmelt runoff. Results also demarcate areas of the delta where lakes are more resilient to factors that cause drawdown. The former defines the Peace sector, which is influenced by floodwaters from the Peace River during episodic ice-jam flood events, whereas the latter describes portions of the active floodplain environment of the Athabasca sector which receives more frequent contributions of Athabasca River floodwaters during both spring ice-jam and open-water seasons. Efficiency of water isotope tracers to capture the marked temporal and spatial heterogeneity in lake water balances during this 5 year time span, and their diagnostic responses to key hydrological processes, serves as a foundation for ongoing lake monitoring, an approach readily transferable to other remote and dynamic lake-rich landscapes.
Logistic and θ-logistic models in population dynamics: general analysis and exact results
Authors: Cufaro Petroni Nicola , De Martino Salvatore , De Siena Silvio
Published: August 2020

Stochastic logistic and θ-logistic models have many applications in biological and physical contexts, and investigating their structure is of great relevance. In the present paper we provide the closed form of the path-like solutions for the logistic and θ-logistic stochastic differential equations, along with the exact expressions of both their probability density functions and their moments. We simulate in addition a few typical sample trajectories, and we provide a few examples of numerical computation of the said closed formulas at different noise intensities: this shows in particular that an increasing randomness—while making the process more unpredictable—asymptotically tends to suppress in average the logistic growth. These main results are preceded by a discussion of the noiseless, deterministic versions of these models: a prologue which turns out to be instrumental—on the basis of a few simplified but functional hypotheses—to frame the logistic and θ-logistic equations in a unified context, within which also the Gompertz model emerges from an anomalous scaling.
Exposure to cough aerosols and development of pulmonary COVID-19
Authors: Vanden Driessche Koen , Nestele Jeremy , Grouwels Jeroen , Duval Els LIM
Published: August 2020

We hypothesized that most patients with severe pulmonary COVID-19 were exposed to cough aerosols. Among patients that were almost 100% certain which person infected them, only 14 out of 38 overall, and 9 out of 25 hospitalized patients requiring supplemental oxygen, were infected by someone who coughed, which did not support our hypothesis. Talking, especially with a loud voice, could be an alternative source generating SARS-CoV-2 aerosols. Further research is needed to determine how SARS-CoV-2 spreads. Avoiding to talk when you are not wearing your mask and not talking with a loud voice, ‘voice etiquette’, could be other public health interventions worthwhile exploring.
The Effects of Climate Change on Snow Leopards at the Hengduan Mountain Region
Authors: Shen Qiushi
Published: August 2020

Snow leopard is one of the top predators and umbrella species of Hengduan Mountain (HM) region. Conserving snow leopard is vital in preserving this biodiversity hot spot. Climate change (CC) is imposing negative influences on snow leopard populations. This research combines and analyses recent research papers on this topic. It turns out that snow leopards are generally influenced by CC in three ways. Firstly, climate change enables forest to move to higher elevation to occupy grasslands, the main habitats of snow leopards. Therefore, snow leopard habitat shrinks and suffers greater fragmentation. Secondly, climate change makes grasslands more vulnerable to degradation, thus threatening preys of snow leopards. Thirdly, CC causes leopards to move to previous snow leopard habitats. As a result, there are risks of competition between snow leopards and leopards. This research appeals for more observation to better analyse snow leopard’s response to climate change.
Existing Water Balance in the Bago River Basin, Myanmar
Authors: Phue H. T. , Chuenchooklin S.
Published: August 2020

Water systems have complex constituent interactions requiring development and evaluation of management amidst uncertainties of climate and constrained natural resources. This paper outlines water resources planning is developed based on the current water resources availability and demand situation by using Water Evaluation and Planning (WEAP) model to evaluate an existing water balance of the Bago River Basin, Myanmar. The study area is approximately 2,660 km2 and the Bago River is the main water resources for demand purposes of Bago township with gauging stations. The water resources planning from upstream of Bago river to Bago Township was calibrated and vilified with quantitative statistics (coefficient of determination, R2; Nash-Sutcliffe efficiency, NSE and Root mean square error, RMSE). The calibrated results fitted to the observed data during 2011-2015 with R2 = 0.99, NSE = 0.88, and RMSE = 24 m3/s, and validated in 2016-2018 with R2 = 0.99, NSE = 1, and RMSE = 10 m3/s, respectively. The results showed the model advanced through WEAP is highly proficient and exhibited great performance to manage available water resources and indicated that currently the basin has sufficient water to meet the water demands in the basin.
Game behavior among multi stakeholders in the process of haze control*
Authors: Zhenyu Zhang , Xuemei Yang , Fan Jia , Zheng Wen
Published: August 2020

The contradiction between economic development and pollution control is becoming increasingly prominent, which is a huge problem that China’s economic development transformation must face and solve at this stage. Among them, the governance of haze is the crux because of its great impact on health. The game behavior of haze governance involves many subjects. After considering the specific situation of the game in reality, this paper constructs a mixed strategy model of multi stakeholders, including the central government, local government, enterprises and the public. In addition to the direct participation of local governments and enterprises in the game, the central government and the public indirectly participate in the final game results through supervision and public opinion. Based on the analysis of the game results, in order to better control the haze and achieve green development, enterprises should strengthen environmental self-discipline, local government and central government should cooperate effectively, and the public should actively participate in it to form a strong influence of public opinion.
Comprehensive Assessment of the availability of selenium resources in Wucheng based on the analytic hierarchy process
Authors: Shao Yixian , Xie Bangting , Zhang Xiang , Xiao Hua
Published: August 2020

In this study, selenium content, soil nutrient elements and environmental quality are considered comprehensively as the main factor, weight of each index is calculated by analytic hierarchy process and Yaahp software, and spatial distribution of evaluation results is reflected by Geographical Information System. Wucheng district is taken as a case area and classified into some regions for selenium utilization. The southern mountainous and hilly area is suitable for the development of selenium-rich ecological tourism, the northern alluvial plain is suitable for the development of selenium-rich agriculture, Zone III-IV are not suitable for natural selenium-rich agriculture, Zone V is forbidden to farm because of the pollution of heavy metals.
Research on high-resolution water pollutant source list of Daqing River Basin (Baiyangdian)
Authors: Bian Wei , Wang Mingxiao , Liu Yuan , Zhang Jingwei , Li Ruihong , Zhao Na , Hao Mingliang
Published: August 2020

With the refinement of water environment management in the basin, the work of Water Pollutant Source List (WPSL) has been carried out. The article separately calculates the pollution load of point sources and area sources, among which point sources include industry sources, sewage treatment plants, large-scale livestock and poultry farms, area sources include urban runoff, rural life, agricultural planting, and rural livestock and poultry farming. Pollutants include chemical oxygen demand (COD), ammonia nitrogen (NH3-N), total nitrogen (TN), and total phosphorus (TP). Based on a certain spatial induction method, the pollution load is assigned to a grid of 1km×1km, and a high-resolution water pollution source list is established, which provides a refined basic database for environmental management.
Study on space environment safety based on satellite collision
Authors: Hongqiang Sun , Zhanyue Zhang
Published: August 2020

In order to avoid collision with SpaceX’s Starlink44 satellite, the European space agency (ESA) said on September 2, 2019 that it fired the thrusters of the Aeolus satellite to avoid collision. In this paper, the collision probability of two space objects is analyzed. In addition, considering the crowded space environment in the future, the number of collisions in a certain period of time was simulated. Meanwhile, compared with the number of possible collisions within 365 days of the existing space target and the number of possible collisions after the addition of Starlink satellite group. The result shows that the future space environment will be much more crowded than expected. On this basis, some reasonable suggestions are put forward for the future space development to ensure the safety and reliability of the future space.
Measures for the optimization and management of construction safety based on BIM technology
Authors: Li Yan , Wu Yansheng , Gao Xiong
Published: August 2020

BIM technology is a kind of new technology application that runs through all kinds of engineering design, construction and follow-up management, and in the course of popularizing and applying the relevant application technology in the past two decades, it has played an important supporting role in promoting the development of China’s construction industry. With the continuous improvement of the development depth of related software, BIM technology has also played a great role in the construction safety management of construction. Based on the advantages of BIM technology application, combined with steel structure construction and assembly concrete construction, this paper puts forward the optimization measures of construction safety management, and makes due contribution to the improvement of quality control level in China’s construction industry.
The expression of social pro-environmental preference influence on green consumption behavior
Authors: Chen Wenhua , Xia Nian
Published: August 2020

With the increasing of social pro-environmental preference, people receive various “green” signals that influence their consumption decisions. The purpose of our work is to establish a green consumption behavior research model based on social pro-environmental preference. We explore the three expressions forms (regulation, price and public opinion) of social pro-environmental preference, and their expressions content in consumer green purchase and green disposal, as well as the influence mechanism on green consumption. The research results show that the regulatory expression of pro-environmental preference (energy-efficient certification), and the price expression of pro-environmental preference (price discount) have a significant positive effect on green disposal behaviors; environmental online public opinion has a significant positive impact both on green product purchases and green disposal behavior.
Prediction of compressive strength of High-Performance Concrete by Random Forest algorithm
Authors: Pengcheng Liu , Xianguo Wu , Hongyu Cheng , Tiemei Zheng
Published: August 2020

The prediction results of the compressive strength of high-performance concrete (HPC) based on intelligent algorithms are seriously affected by the input variables. In this study, the Random Forest algorithm (RF) is introduced to optimize the number of input variables by evaluating the importance of influencing factors, and then predict the 28-day compressive strength through Random Forest Regression. The results show that this method is effective for the optimization of input variables, and when the parameters are set within a reasonable range, better prediction results can be obtained than non-variable optimization.
Preparation of Micro/nano Sized AI2O3 Using the By-product of Al-based Composites Hydrolysis Reaction
Authors: Guan Xu , Zhou Zheng , Luo Ping , Wu Fengshun , Dong Shijie
Published: August 2020

In this paper, Al-based composites used for hydrogen production have been prepared by ball milling process. In order to reduce the cost of Al-based composites, we prepared micro/nano sized Al2O3 with the by-product of Al-based composites hydrolysis reaction. X-ray diffraction (XRD), scanning electron microscopy (SEM), and Mastersizer 2000 size analyzer are used for the analysis of the samples. The results show that Al2O3 phase is formed after the by-product milling for 4h and the by-product milled for 6h can reach micro/nanometer level. It is beneficial to reduce the cost of Al-based composites, which can promote the wide application of Al-based composites in the field of hydrogen production.
Study on Mathematical Model for Condensation Heat Transfer in Two-phase Closed Thermosyphon
Authors: Ren Bin , Pu Zhe , Du Yannan , Tang Xiaoying , Yang Yuqing , Lu Hongliang
Published: August 2020

The two-phase closed thermosyphon is a special heat pipe utilizing gravity instead of capillary force to return the liquid to evaporator. Some assumptions for Nusselt model are not true in the condenser section, resulting in the complexity of condensation. In this paper, a numerical model based on Nusselt’s model is developed considering vapour-liquid interfacial shear stress. The distributions of local parameters such as shear stress, liquid film thickness are analysed. The variation of average heat transfer coefficient with temperature difference is displayed. And the average heat transfer coefficients predicted by numerical model are compared with values calculated from other references. The results show that both the shear stress and liquid film thickness increase as condensation proceeds. But the growth rate decreases along the axial direction. The average heat transfer coefficients predicted by this model is lower than that calculated by Nusselt’s correlation especially at higher heat load, indicating that shear stress really reduces the heat transfer performance.
Numerical analysis of the influence of the number of blades on the dynamic performance of a drone
Authors: Sirca A A , Mariasiu F , Morariu S , Vlad N
Published: August 2020

The use of Unmanned Aerial Vehicles and known under the generic name of drones is increasingly present in different economic sectors, due to the versatility they offer in solving specific problems. The specific problems to be solved, however, raise the need for the technical characteristics of the drones to be optimized according to the specific usage. In the case of drones used in technological processes in agriculture, they must offer a high autonomy, that can be increased by optimizing their weight. The paper proposes the study of the dynamics of the air flow according to the configuration of the drone rotor (2 and 3 rotor respectively) by numerical analysis methods for the further development of a drone that will be used in the phytosanitary treatment process of agricultural crops. The parameters evaluated and compared are the specific parameters for characterizing the airflow: velocity and relative pressure (at different nacelle’s section, both in horizontal and vertical directions). The obtained results show that the most constant, dense and homogeneous velocity field was obtained from the 3-blade configuration of the rotor.
Aspects of creativity management in the Romanian industry and doctoral research
Authors: Moraru G M , Popescu L G
Published: August 2020

Creativity management is an extremely vast field, which has preoccupied us for many years. In this paper we present some aspects of the junction between creativity management in academic research and creativity management in industry. Our aim was to compare how creativity management influences the results of the PhD students’ researches with the way in which creativity management in industry influences the organizational performances and competitiveness. The research based on questionnaires was carried out in parallel in technical and economic faculties in Romania, as well as in industrial organizations. Even if the variables analysed on the two samples of respondents are different, because they have different aims and interests regarding the use of creativity management, we have made comparisons between the two sets of variables and proved that the impact of creativity management in PhD students’ research is high, but the impact of creativity management in Romanian industry is low.
Overcoming the barriers of consignment stock policy implementation in a manufacturing company
Authors: Faur M , Sipos A , Bungau C , Gherghea C I
Published: August 2020

The present study represents a part of a wider research, centered on consignment stock program adoption and implementation in a supply chain governed by lean and agile strategies. The paper attempts to explore the challenges and the barriers which may occur prior or during the implementation stages of the project, to identify and mitigate the risks and also to establish safe approaches to overcome project failure. The work includes a brief overview on consignment stock model and its benefits, along with the implementation risks perceived by the internal stakeholders, mostly viewed as a human factor reaction to change. The methodology consists of a survey addressed to the business functions directly affected by the project, in order to identify the main barriers and risks, and of an assessment of the risk severity and its distribution within and among different groups of stakeholders, using One-way ANOVA statistical method. A solutions framework to the identified risks is proposed, in order to overcome implementation barriers.
New research direction on performance and co-creation: a literature review
Authors: Tudose M B , Agafitei G , Avasilcai S
Published: August 2020

The purpose of this study is to review literature on topics of performance and co-creation. The study has two premises: performance includes economic and behavioural aspects; co-creation produces direct and indirect effects on performance. In order to validate these two, we took into consideration all studies available on WoS platform. Applying different selection criteria, we obtained a sample of 14 studies published between 2016 and 2020. Through observation, comparison and logic deductions we were able to appreciate the authors` interest in identifying new research directions. Thus, we show that: a) co-creation has a direct impact on performance, competitiveness and value for stakeholders; in this context, performance is regarded as a multidimensional concept with wide implications in various fields such as management, financial, marketing, innovation etc.; b) co-creation has an indirect influence on performance through elements like: brand, product-service systems and cross-sector partnerships. These aspects are empirically validated in different context. The results of our research prove to be useful from two points of view: theoretical (because the study presents in an authentic manner the state of the knowledge on performance and co-creation) and methodological (because it offers support to all those interested in finding new research directions).
Exploring the opportunity for a hybrid methodology in project management: a focus group approach
Authors: Bagiu N , Avasilcăi S , Alexa L
Published: August 2020

Nowadays, project-based work is no longer a challenge for a today company. Optimizing the workforce, better managing the results, delivering in time, quality and budget (the triple constrains [1]) are just a few of the advantages. Still, to re-organize an entire company into a project-based organization requires a lot of efforts and energy across its departments and teams. However, some companies step forward and change the project management methodologies multiple times. That brings another wave of changes, stress and reorganizations combined with a complex organizational phenomenon, which requires far more effort than just to replace the current tools and technologies with new ones [2]. Thus, the main purpose of this paper is to reflect and present the results of the workshop called “Going Agile – the journey”, which was held on Project Management Forum 2019, a Conference organized inside of Continental Automotive Romania for all project managers working in the company. Based on the focus group technique there was identified the main struggles associated with the adoption of Agile methodology within Automotive Industry, the similarities with the plan-driven methodologies and willingness to advance the agility in company’s daily working life.
Simulation modelling as a method of risk analysis in real estate valuation
Authors: Gromova E A , Pupentsova S V
Published: August 2020

The advent of the fourth industrial revolution was marked by the fact that changes became the main characteristics of the new time. It means a high level of uncertainty and instability in the business environment. The real estate market, being a part of the investment market, is changing. The current development of Russia’s investment potential leads to an increasing need for professional management of the profitability of such investments. Thus, the main goal of this research is to present non-traditional methods of risk assessment, which should be used in determining the market value of the real estate object at the present time. Simulation modelling is a method of research in which the system under study is replaced by a model that describes the real system with sufficient, with which experiments are conducted in order to obtain information about this system. An example of the application of simulation modelling in the analysis for the purpose of choosing the best and most effective use of a land plot as conditionally free is given. Financing of investment projects is a dynamic process that requires a risk assessment.
A simplified yet enhanced and versatile microfluidic platform for cyclic cell stretching on an elastic polymer
Authors: He Yingning , Mao Tianjiao , Gu Yexin , Yang Yuqian , Ding Jiandong
Published: August 2020

While the microfluidic chips for cell stretching and real-time cell observations have so far been composed of three layers, the present work reports a two-layer one, which is, on the surface, not available due to the ‘inherent’ difficulty of unstable focusing on cells in the microscopic observation under the stretching operation, etc. Herein, this difficulty was overcome to a large extent, in the case of appropriate device parameters, which were determined based upon finite element analysis and orthogonal experimental design. The novel chip was fabricated and confirmed to work in frequency up to 2 Hz and stretching ratio up to 20%. We further performed uniaxial stretching experiments of human mesenchymal stem cells on an elastic polymer, polydimethylsiloxane, and the cells were found to be highly oriented perpendicular to the stretching direction. The short working distance on this simplified two-layer chip enabled clear observation of microtubules and stress fibers of cells under an optical microscope. We also tested radial stretching and gradient stretching as proofs of concept of the extendibility of this type of chip. Therefore, in spite of being simpler, the two-layer chip suggested in this study exhibited enhanced and versatile functions, and the present work has thus afforded a new methodology of fabrication of microfluidic chips for the study of cells on biomaterials under a mechanical stimulus.
Fabrication of thermal energy storage wood based on graphene aerogel encapsulated polyethylene glycol as phase change material
Authors: Lin Xianxian , Jia Shifang , Liu Jingyi , Wang Wenbin , Cao Huimin , Guo Xi , Sun Weisheng
Published: August 2020

Thermal energy storage wood (TESW) was fabricated by using graphene aerogel encapsulated polyethylene glycol (PEG) as phase change material and wood as the matrix. The microstructure of TESW was investigated by scanning electron microscope (SEM), the thermal properties of TESW was determined by differential scanning calorimetry (DSC), thermal gravimetric analysis (TG) and laser flash diffusivity apparatus (LFA). The results showed that: (1) graphene aerogel (GA) encapsulated PEG composite was founded in the lumens of wood, there was no apparent interface between PEG and graphene aerogel; (2) the melting and freezing enthalpy of TESW were 11.81 and 27.91 J g−1, respectively. The melting and freezing point were 20 °C and 15 °C, respectively, which were suitable for human comfortable temperature; (3) incorporation of graphene aerogel improved the thermal conductivity of TESW apparently. Thermal conductivity of TESW was 0.374 W (m*K)−1, which increased about 274% compared to pure wood; (4) TG and hygroscopicity test indicated that the TESW had excellent thermal and dimensional stability. The TESW was suggested as energy conservation building material for indoor temperature regulating due to its comfortable phase change temperature and prior latent heat.
26 Results of hyperbolic partial differential equations in B-poly basis
Authors: Bhatti Muhammad I , Hinojosa Emilio
Published: August 2020

A two-variable process to estimate results of Hyperbolic Partial Differentiation (HPD) equations in a B-Polynomial (B-Poly) bases is established. In the proposed process, a linear product of variable coefficients and B-Polys is manipulated to express the predicted solution of the HPD equation. The variable coefficients of the linear mixture in the results are concluded using Galerkin technique. The HPD equation is converted into a matrix which when inverted provided the unknown coefficients in the linear mixture of the solution. The anticipated solution is constructed from the variable coefficients and B-Poly basis set as a product with initial conditions implemented. Both the effectiveness and precision of the process depend on the number of B-Polys employed in the results and degree of the B-polys utilized in the linear sequence. The current process is applied to solve four linear examples of the HPD equations with various initial conditions. An excellent agreement was found between exact and estimated results and in some cases estimates were exact. The current process renders a higher degree of efficiency and accuracy for solving the HPD equations. The process can be easily employed in other fields such as physics and engineering to solve complex PDEs in two variables.
Visualizing one-dimensional non-hermitian topological phases
Authors: Yang X M , Wu H C , Wang P , Jin L , Song Z
Published: August 2020

We develop a graphic approach for characterizing one-dimensional non-Hermitian topological phases. The eigenstates of energy bands are mapped to a graph on the torus, where a nontrivial topology exhibits as links. The topology of band touching exceptional points is a crucial aspect of a non-Hermitian system; the existence of exceptional point results in networks. We discuss the parity-time (

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) symmetric two-band models. The pseudo-anti-Hermiticity protects the band topology, and the eigenstate graphs in the exact

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-symmetric phase locate on the torus surface under the

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symmetry protection. For the Su-Schrieffer-Heeger ladder, the eigenstate graph is a Hopf link in the gapped nontrivial phase; chiral-time symmetry protects that the movable exceptional points appear in pairs in the real-energy gapless phase, and each exceptional point splits into a pair of exceptional points when the

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symmetry breaks. The proposed graphic approach is applicable in one-dimensional N-band models. Our findings provide insight into one-dimensional non-Hermitian topology phases through visualizing the eigenstates.