bluuebunny/crossref_metadata_2025 huggingface dataset:
Transformer winding type recognition based on FRA data and a support vector machine model
Authors: Mao Xiaozhou , Wang Zhongdong , Crossley Peter , Jarman Paul , Fieldsend‐Roxborough Andrew , Wilson Gordon
Published: May 2020

Frequency response analysis (FRA) is regarded as the most effective technique to detect mechanical faults of transformers. Over the years, FRA measurement data have been collected by utilities into transformer asset databases. The characteristic of FRA data is fundamentally determined by the transformer's equivalent electrical circuit, which consists of inductance and capacitance parameters that are windings' design and structure dependent. Different winding types tend to have different FRA characteristics, and a transformer's design information such as winding type, dimension etc. is often not known to the utility but critically important for asset management. This study reviews the state‐of‐the‐art transformer FRA databases and application of machine learning techniques in this field, and proposes to apply a support vector machine (SVM) model onto the FRA data to identify the winding type. The SVM model is first trained by FRA traces of transformers with known winding types, and after testing, the SVM model is then applied to FRA traces with unknown winding information. A set of data from the UK's National Grid FRA database, was used to demonstrate and verify the SVM model. All transformers used in this study are 400/275/13 kV transmission transformers, which were designed using four different winding types, namely multiple layer, plain disc, interleaved disc and single helical windings. The proposed method can successfully identify the correct winding type.
Outage analysis for NOMA‐based energy harvesting relay network with imperfect CSI and transmit antenna selection
Authors: Mondal Soumen , Dhar Roy Sanjay , Kundu Sumit
Published: May 2020

In this study, a relay assisted order energy harvesting‐based non‐orthogonal multiple access (NOMA) network is considered where the relay harvests energy from radio frequency signal of the source. A transmit antenna selection scheme is considered at the source under imperfect channel state information (CSI). The outage probability of order NOMA network is analysed and a closed‐form expression of it is obtained. A comparative performance study is carried out with perfect and imperfect successive interference cancellation at the receiver. The impact of a number of antennas available at the source on outage performance and the effect of imperfect CSI on the outage performance are also presented in this work. The upper limit of the order of the NOMA network to be supported for a given threshold signal to interference plus noise ratio (SINR) is also estimated.
Mitigating the desynchronisation attack in multiserver environment
Authors: Jan Saeed Ullah , Qayum Fawad
Published: May 2020

Currently, every user outsources a huge amount of shared secrets remotely from different servers and utilises synchrony resources. To make all types of operations secure for the end‐user, synchronous storage is vital and asynchronous storage might lead to the unavailability of successful services. Hence, a robust authentication scheme is mandatory for such purpose which not only confirms the synchrony of the distributed shared resources but also secure access to shared secrets. So far no one has offered an accurate and flawless secure mechanism despite serious attempts. For this purpose, the authors have designed an improved and robust authentication protocol to ensure the security, integrity, and confidentiality of information and synchrony of shared secrets up to a maximum level. The security of the proposed dynamic mechanism has been verified both formally using random Oracle model and verification toolkit ProVerif2.00 and informally using assumptions and theorems. A delicate balance between security and performance has been shown in the performance analysis section of the study.
Secrecy precoding in MIMOME wireless communication system under partial CSI
Authors: Dong Runze , Wang Buhong , Cao Kunrui , Li Xia
Published: May 2020

In this study, a precoding scheme which is called singular value decomposition and null space (SVDNS) based scheme is proposed to enhance physical layer security of a multiple‐input multiple‐output multiantenna eavesdropper (MIMOME) system. Under the partial channel state information (CSI) of the eavesdropper, the precoding matrix for the information bearing signal is constructed firstly via SVDNS‐based scheme to acquire a compromise between improving performance of the main channel and impairing that of the wiretap channel. Then the optimal power allocation over subchannels formed by precoding matrix is obtained through solving the secrecy rate maximise problem to further improve secrecy performance. After that, under the scenario that CSI of the wiretap channel is less knowable, precoding matrix for artificial noise (AN) is proposed via SVDNS‐based scheme, and then the optimal power allocation between the information bearing signal and AN is obtained while optimal power allocation over subchannels is solved subsequently. Simulation results show that the SVDNS‐based scheme with optimal power allocation achieves a higher secrecy rate than the existing schemes, and the SVDNS‐based scheme with AN aiding could make up for the performance degradation of it without AN in the situation that CSI of the wiretap channel is more unknowable.
Design and analysis of decoupled tetra‐polar ring‐coils for wireless power transfer in rotary mechanism applications
Authors: Zhou Wei , Zhu Zhehui , Mai Ruikun , He Zhengyou
Published: May 2020

Decoupling of same‐sided coils is a critical issue for multi‐input and/or multi‐output inductive power transfer (IPT) systems. The mutual inductance between the same‐sided coils may lead to the system detuning and the decrease of power transfer capacity and efficiency. In this study, a tetra polar ring coils (TPR‐coils) and its decoupling method are proposed for IPT systems applied to rotary mechanism. Firstly, an analytical expression, which illustrates the relationship between the mutual inductance and geometric parameters of coaxial cylindrical helical coils, is given. Then the equivalent circuit model of TPR‐coils is established, and the mutual inductance constraints for the decoupling of TPR‐coils are proposed. Combined with the expression of mutual inductance, a geometric parameter solution of decoupled TPR‐coils is derived. The correctness of theoretical analysis is verified by finite element method simulations and experiments. The experimental results show that the mutual inductance between the same‐sided coils can be reduced to 0.6 μH, and the effectiveness of TPR‐coils is also verified on an IPT prototype with 231 W power and over 86% efficiency.
Optimal generation scheduling of fixed head hydrothermal system with demand‐side management considering uncertainty and outage of renewable energy sources
Authors: Basu Mousumi
Published: May 2020

Due to the rising infiltration of renewable energy sources, it is indispensable to investigate its brunt on the optimal power generation scheduling. However, the highly intermittent nature of renewable energy sources and their higher rate of outages may harm the entire grid. This work recommends fast convergence evolutionary programming (EP) with a time‐varying mutation scale (FCEP_TVMS) for solving fixed head hydrothermal scheduling incorporating pumped‐storage‐hydraulic unit with demand‐side management considering the uncertainty and outage of renewable energy sources. Simulation outcomes of the test system have been matched up to those acquired by fast convergence EP, colonial competitive differential evolution and heterogeneous strategy particle swarm optimisation. It is seen from the comparison that the recommended FCEP_TVMS technique can give a better‐quality solution.
Emergency wind power plant re‐dispatching against transmission system cascading failures using reverse tracking of line power flow
Authors: Hoseinzadeh Bakhtyar , Blaabjerg Frede , Chen Zhe , Teodorescu Remus
Published: May 2020

Due to high wind power penetration into power system, synchronous generators may no longer be the dominant generation, which implicitly requires participation of wind power plants (WPPs) in the load‐frequency control (LFC). Frequency, a common variable throughout the entire power system, is the key variable for LFC, which causes equal contribution of all distant and nearby WPPs in LFC. Power transfer from distant WPPs to the event location may overload the middle transmission lines leading to cascading failures. This study proposes an online dispatch rescheduling algorithm for WPPs participating in the LFC task to prevent over loading of transmission lines and hence cascading failures following severe frequency contingencies. The WPP dispatch limits are calculated based on line ampacity for each generation unit participating in the LFC task. Numerical simulations carried out in DigSilent PowerFactory on 39 bus IEEE standard test system, demonstrates the efficiency of suggested online dispatch rescheduling technique for keeping the loading rate of transmission lines, bus voltages and system frequency in range.
Simplified and fast method without considering filter for voltage flicker detection
Authors: Xia Rui , Gao Yunpeng , Li Canbing , Wu Cong , Wang Chao
Published: May 2020

Voltage fluctuations caused output variation in the distributed energy system (such as solar, photovoltaic, and wind) produce flickers. The extraction of voltage flicker envelope parameters and accurate calculation of voltage flicker values are important for voltage flicker detection. Traditional digital filters need to be calculated according to the sampling frequency before they can be designed so that the flicker meter can only sample at a fixed frequency. To overcome the shortcomings of digital filters, a new method for measuring flickers is presented in this study. The proposed method uses analytical mode decomposition (AMD) based on spectral correction and a novel constructed mutual convolution window. The voltage flicker envelope can be extracted using an AMD method, which can replace the filter used in traditional methods, it can be analysed to obtain the corrected spectrum, which is based on an improved fast Fourier transform. The proposed method simplifies the voltage flicker detection process and exhibits high detection accuracy, which with lower detection relative error and stronger anti‐interference ability. The simulation analysis and experimental results show that this approach can effectively overcome problems associated with voltage flicker measurements, such as single modulation wave frequency change and multi‐frequency modulation wave fluctuation.
Robust distribution system state estimation with hybrid measurements
Authors: Santhosh Kumar C. , Rajawat Ketan , Chakrabarti Saikat , Pal Bikash C.
Published: May 2020

With growing connection of distributed energy resources, availability of demand side response technologies, deployment of smart meters, the distribution system needs advanced network automation for running the system efficiently. State estimation is the core driver of network automation. While the output from SMs will make the state estimation more accurate, advanced metering infrastructures come with several challenges such as noisy, erroneous measurement including lost or missed measurements, exposure to cyber attack and so on. This study proposes a three‐phase unbalanced distribution system state estimation which is robust against noisy distribution system measurements, bad data attacks and missing or delayed measurements. This method considers measurement from hybrid sources such as SCADA, micro‐phasor measurement units ( PMUs) and SMs. Kalman smoother is used to fill the missing measurements and expectation‐maximisation based forecasting is used to interpolate the hybrid measurements to a common timestamp and compensate for the delay in SM measurements. Extensive numerical comparisons are made on IEEE 13, 37 and 123 bus systems to test the robustness of the proposed DSSE against delayed SM measurements and bad or noisy data. An IEEE 24 bus system is modelled and real‐time measurement devices are interfaced to it in Hypersim. The data from the hybrid measurement devices of IIT Kanpur smart grid is also used to test the robustness of the proposed method.
Dielectric characterisation of epoxy nanocomposite with barium titanate fillers
Authors: Zafar Romana , Gupta Nandini
Published: May 2020

High permittivity materials are currently in use for mitigation of electrical stress in high‐voltage apparatus and energy storage systems. In this work, epoxy‐based high permittivity nanocomposites with Barium titanate (BaTiO3) nanofillers are considered, for the purpose of stress mitigation. Uniform dispersion of the fillers in the polymer up to 10% by volume is achieved. Apart from the use of as‐received fillers, the effect of using surface‐functionalised nanoparticles (with 3‐glycidoxypropyltrimethoxy‐silane) before use is also investigated. The nanocomposite is characterised in terms of its complex permittivity, DC conductivity, short‐term AC breakdown strength and space charge accumulation, to gauge its suitability for use in high‐voltage insulation. Complex permittivity is measured using broadband dielectric spectroscopy over a broad frequency range of 1 mHz to 1 MHz. DC conductivity is studied from polarisation–depolarisation current measurements. Short‐term AC breakdown strength tests are performed at power frequency (50 Hz). Space charge density along the sample thickness is obtained using pulsed electro‐acoustic technique. A computational case‐study is presented to show the feasibility of using the high permittivity nanocomposite for electric stress control in high‐voltage equipment (viz., at mounting flanges of 69 kV bushings).
ALMA and VLA reveal the lukewarm chromospheres of the nearby red supergiants Antares and Betelgeuse
Authors: O’Gorman E. , Harper G. M. , Ohnaka K. , Feeney-Johansson A. , Wilkeneit-Braun K. , Brown A. , Guinan E. F. , Lim J. , Richards A. M. S. , Ryde N. , Vlemmings W. H. T.
Published: May 2020

We first present spatially resolved ALMA and VLA continuum observations of the early-M red supergiant Antares to search for the presence of a chromosphere at radio wavelengths. We resolve the free-free emission of the Antares atmosphere at 11 unique wavelengths between 0.7 mm (ALMA band 8) and 10 cm (VLA S band). The projected angular diameter is found to continually increase with increasing wavelength, from a low of 50.7 mas at 0.7 mm up to a diameter of 431 mas at 10 cm, which corresponds to 1.35 and 11.6 times the photospheric angular diameter, respectively. All four ALMA measurements show that the shape of the atmosphere is elongated, with a flattening of 15% at a similar position angle. The disk-averaged gas temperature of the atmosphere initially rises from a value of 2700 K at 1.35 R⋆ (i.e., 0.35 R⋆ above the photosphere) to a peak value of 3800 K at ∼2.5 R⋆, after which it then more gradually decreases to 1650 K at 11.6 R⋆. The rise in gas temperature between 1.35 R⋆ and ∼2.5 R⋆ is evidence for a chromospheric temperature rise above the photosphere of a red supergiant. We detect a clear change in the spectral index across the sampled wavelength range, with the flux density Sν ∝ ν1.42 between 0.7 mm and 1.4 cm, which we associate with chromosphere-dominated emission, while the flux density Sν ∝ ν0.8 between 4.3 cm and 10 cm, which we associate with wind-dominated emission. We show that the Antares MOLsphere is transparent at our observed wavelengths, and the lukewarm chromosphere that we detect is therefore real and not just an average of the cool MOLsphere and hot ultraviolet emitting gas. We then perform nonlocal thermal equilibrium modeling of the far-ultraviolet radiation field of another early-M red supergiant, Betelgeuse, and find that an additional hot (i.e., > 7000 K) chromospheric photoionization component with a much smaller filling factor must also exist throughout the chromospheres of these stars.
Integral assessment of heavy metal pollution in Don River estuary soils
Authors: Nevidomskaya Dina , Minkina Tatiana , Fedorov Yuri , Nazarenko Olga , Kravtsova Natalya , Litvinov Yuri
Published: May 2020

Based on the cumulative pollution index, spatial distribution maps were obtained to establish categories of soil pollution taking into account the total content of heavy metals and the mobile forms of metals in the Don River estuarine region. The objects of the study included samples of zonal soils (Chernozem) and intrazonal soils (Fluvisols) from monitoring plots. The total concentrations of Mn, Cr, Ni, Cu, Zn, Pb, and Cd in the soils were determined by X-ray fluorescent scanning spectrometer. Mobile heavy metals compounds were transferred to a solution by extraction of 1 N NH4Ac, pH 4.8. When calculating the total metal content, it was shown the studied soils had generally an acceptable pollution category but taking into account mobile forms the categories of soils contamination variate up acceptable to extremely dangerous. The most polluted sites are associated with the estuary of small rivers and the branches flowing into the Taganrog Bay, the territory of the Taganrog port and its terminals, and road bridges. In line with hight categories of pollution, the use of the soils for cropping should be limited, and the cultivation of concentrator plants is excluded.
Heavy metals in the organic soil horizon of the Northern taiga forests resulting from industrial air pollution
Authors: Evdokimov Alexander
Published: May 2020

This study focuses on heavy metals contained in organic soil horizons resulting from the industrial air pollution caused by local enterprises. Polymetallic dust containing heavy metals is one of the main by-products in the smelting of non-ferrous metals. We evaluated the contents of Ni, Cu, and Co in the upper soil horizons containing the maximum amount of these pollutants (due to the formation of stable compounds with organic components of these horizons). Sampling was carried out at various distances from the source of pollution at previously established test sites. The study found acid-soluble heavy metals at various distances from the source of pollution and revealed the regularity of their content, both qualitative and quantitative.
Assessment of the genotoxicity of water and soil in the places of storage of reserves of old pesticides by Allium-test
Authors: Cherednichenko Oksana , Nuraliev Serikbay , Bekmanov Bakytzhan , Pilugina Anastassiya , Dzhansugurova Leila , Baigushikova Gulnara
Published: May 2020

Pesticides and persistent organic pollutants (POPs) are a serious environmental problem for almost all countries of the world. The toxic and mutagenic activity of samples of natural water and water extracts of soils collected near the storage sites of old and prohibited pesticides located in the villages of Kyzylkairat, Amangeldy, Beskainar, Belbulak, Enbekshi. Territories of comparison Basshi village (Altyn Emel National Park) and near farmland, where pesticides were used in the past (Taukaraturk village, Almaty region) was investigated. Allium cepa L. was used as a biological test system. The mitotic activity and the frequency of disturbances at different stages of mitosis in onion root meristem were evaluated. Chemical analysis showed that in all soil samples the total content of 24 POPsPesticides exceeds the maximum permissible concentration (MPC). It was established that the level of mitotic activity of Allium cepa cells in all samples was slightly reduced compared with the control. In soil samples, the frequency of micronuclei in interphase cells (0.22-3.25%) is higher than in water samples (0.36-0.99%) (control 0.41%). The revealed increased level of cytogenetic disorders correlates with the total content of organochlorine pesticides.
Specificity of accumulation of hydrocarbons in various components of geosystems
Authors: Khaustov Aleksandr , Redina Margarita
Published: May 2020

The results of the analysis of thermodynamic characteristics of the processes of hydrocarbon amassment in the components of geochemical systems are presented (waters, soils, plants and other substances forming ecosystem). The need to use an ideology and apparatus for calculating thermodynamics is due to the complexity and diversity of mass transfer in interacting media. The material and energy flows of marker compounds, polycyclic aromatic hydrocarbons (PAHs), are analyzed: Naphthalene (Naph), Acenaphthene (Ace), Fluorene (Flourene), Phenanthrene (Phen), Anthracene (An), Fluoranthene (Flu), Pyrene (Py), benzo[a]anthracene (BaA), Chrysene (Chr), Benzo[b]fluoranthene (BbFlu), Benzo[k]fluoranthene (BkFlu), Benzo[a]pyrene (BaP), Benzo[ghi]perylene (Bghi), Dibenzo[a, h]anthracene (DbA), Indeno[1, 2-cd]pyrene (Ip). Estimates are obtained of the intensity of PAH concentration processes in geochemical systems in different states from the point of view of stability, from clearly unstable to metastable. The role of living matter in the formation of stability of geochemical systems is revealed.
Study of cyantraniliprole sorption in soils of Russia
Authors: Kolupaeva Victoria , Nyukhina Inna , Belik Aleksandra
Published: May 2020

The sorption of the new insecticide cyantraniliprole was studied by the batch equilibrium method. The study of quantitative characteristics of cyantraniliprole sorption by the soils of different types showed that this process is well described by linear isotherms. According to obtained values of Koc, cyantraniliprole belongs to medium-mobility active substances of pesticides. The sorption value of cyantraniliprole was closely correlated with the content of organic carbon and clay. The regression equation of the dependence of Kd on soil organic carbon content was obtained.
Metodological aspects in the studying of soil particle size distribution under contamination and after reclamation
Authors: Zamulina Inna , Burachevskaya Marina , Mandzhieva Saglara , Bauer Tatiana , Barakhov Anatolii , Mazarji Mahmoud
Published: May 2020

In this study, a model experiment was performed under artificial copper contamination of Haplic Chernozem soil. Following the introduction of granular activated carbon (GAC) and biocharin contaminated soil, data on the particle size distribution were obtained. The particle size distribution of Haplic Chernozem was determined by two different methods namely pipette method (PM) and laser diffraction method (LDM). For the LDM, changes in the composition of fractions of more than 0.01 mm were more obvious, while for PM, the main differences were of characteristic for the content of fine fractions less than 0.01 mm.
Contaminated sites investigation. Objectives and methods
Authors: Bica Ioan
Published: May 2020

The past human activities, mainly that related to industrial development caused in many cases a strong contamination of soil, subsoil environment and of groundwater. This type of pollution is a concern because it poses risks to human health and to the ecosystem. More than this, such areas may not be used for new development, requiring solutions for remediation. The management of these sites consists of three main activities: characterization, remediation and, finally, redevelopment. The paper presents a case study dedicated to the first step of contaminated sites management, respectively characterization. This phase is very important, a good characterization could ensure a performant solution for the second step – remediation. Two new techniques for site characterization are presented, as technical principles, but also as performances obtained for the mentioned case study.
Municipal Waste Management in Towns of Switzerland: a Foreign Ecologist’s View
Authors: Mamadzhanov Roman , Zakirova Yulia , Umarov Mykhadi
Published: May 2020

The article presents the results of the research carried out by the foreign ecologists, particularly the study of the system of municipal waste management in the municipality of Maienfeld, Switzerland. The total amount of municipal waste has been calculated. The systems of municipal waste collection, sorting, transportation and recycling have been studied. Besides, four possible scenarios of waste recycling in Maienfeld have been developed. Moreover, the environmental assessment of the waste recycling system by GHG/SLCP emissions has been conducted, and the impact of recycling on the climate has been determined. Finally, taking into account the results of the research, the best scenario of recycling has been proposed.
Ecosystems Transformation and Assessment of Bird Resources in the Republic of Tatarstan (Russia)
Authors: Rakhimov Ilgizar , Ibragimova Kadrya
Published: May 2020

The intensification of economic activities, wide scales of the destruction of the woods, the growth of the areas of the worked lands, creation of water basins, urbanization and other forms of transformation of natural landscapes for last centuries have essentially changed the conditions of animals’ habitation. 305 species of birds can be found within the territory of Tatarstan. We performed an analysis of the state of the ornithofauna over the past 120 years, which allowed us to get estimates of species density and distribution in the republic. The research material is a gain to the knowledge about ornithofauna of Tatarstan, the state of each species populations and may be used to develop a regional monitoring system.
Anthropogenic dynamics and recovery of disturbed landscapes at the Far East Russia permafrost area
Authors: Tikhmenev Pavel E. , Smirnov Andrey A. , Tikhmenev Evgeniy A. , Stanchenko Galina V.
Published: May 2020

The results of studies of anthropogenic landscapes functioning with an assessment on the processes of natural self revegetation are summarized. The principles of accelerated restoration of the ecological and aesthetic value of disturbed landscapes at the permafrost zone are substantiated, based on the data obtained during studying the selfrevegetation processes on disturbed complexes. Development of placer and ore deposits of mineral resources is leading to deep transformation of landscape and to destruction of soil-vegetable complexes. The processes caused by mining-technical activity are leading to variable mechanisms of degradation of soil and vegetables often having complex impact. Results of study of sustainability of soil-vegetable complexes to the impact of mancaused activity have showed the dependence from the structure of the soil profile and it characteristic, from the character of genetic horizons, frozen status of the landscape elements, form the structure and biomass and productivity of vegetation cover.
Manganese and cobalt levels in hair and urine of RUDN University first-year students
Authors: Kirichuk Anatoly A.
Published: May 2020

The objective of the present study was to assess hair and urinary levels of cobalt (Co) and manganese (Mn) in foreign students of RUDN University in comparison to the Russian counterparts. A total of 272 first-year students of the RUDN University originating from Russia, Asia, Middle East, Africa, and Latin America were enrolled in the study. Evaluation of Mn and Co levels in urine and hair was performed using inductively-coupled plasma mass-spectrometry. The obtained data demonstrate that hair cobalt levels were found to be the highest in students originating from Russia and Africa. Similarly, urinary Co levels in subjects from Asia, Middle East, and Latin America were significantly lower than those in the Russian students. The patterns of manganese status were generally similar to those observed for cobalt. Particularly, the lowest hair Mn content was detected in subjects originating from Middle East. Manganese level in urine of students from Africa was significantly higher than that in subjects from Asia, Middle East, and Latin America, but not Russia. It is proposed that specific national dietary patterns as well as geochemistry of Mn and Co may underlie the observed differences.
Biological contamination of soils in urbanized ecosystems by Toxocara sp. eggs.
Authors: Maslennikova Olga , Erofeeva Viktoriya
Published: May 2020

As a result of the study of three sites (two city parks and a special area for walking dogs) on the contamination of Toxocara sp. eggs it was found that 28.0±2.3% of the studied fecal samples from the territories of the Kirov Park were infected with Тохосаrа eggs, 21.0±3.6% of fecal samples from the territory of the Park of the 50th anniversary of the Komsomol and 7.0±0.4% of fecal samples were infected with Тохосаrа eggs selected at a specially equipped dog walking area in the Metrograd residential complex in Kirov. The average rate of dogs which were infected by Toxocara (EI) was 18.7±6.2%. The average rate of contamination of soil by eggs Тохосаrа in the study sites amounted to 34.6%. Contamination of soil samples with eggs of Toxocara sp. in parks was 45.6% and 45.8%, respectively, and in the dog walking area it was 12%. The largest number of dogs, including stray ones, were registered in the parks: 74.8±7.1 and 62.8±7.0 individuals, respectively. There were no stray individuals in the dog walking area, and there were 21.6±1.0 individuals over the entire study period.
Injective envelopes of transition systems and Ferrers languages
Authors: Kabil Mustapha , Pouzet Maurice
Published: May 2020

We consider reflexive and involutive transition systems over an ordered alphabet A equipped with an involution. We give a description of the injective envelope of any two-element set in terms of Galois lattice, from which we derive a test of its finiteness. Our description leads to the notion of Ferrers language.
On pricing and bundling decisions for stackelberg games in parallel channels of substitutable composites
Authors: Keyhanian Sina , Ahmadi Abbas , Karimi Behrooz
Published: May 2020

The paper describes competition within a supply network with parallel distribution channels. Each supply chain in the network is composed of a manufacturer and a retailer. Manufacturers sell two complementary products to the retailers, who then deliver to the end consumers. All players can bundle or not bundle their products assuming that the retail market presents the products in a mixed bundling setting. The motivation of this study is to mainly analyze the impact of cost reduction via manufacturers, on how the whole supply network will behave. We have modeled and solved partly and fully sequential game structures well known as Bertrand and Stackelberg games, where the preceding movers are considered to have more market power. Mathematical and numerical analyses reveal interesting propositions and managerial insights for decision makers who are practicing cost cutting strategies. The combination of different ordinal structures have led to exact mathematical comparisons among 24 games. Results indicate both manufacturers and retailers are better off with simultaneous pricing games. This promotes the concept of coordination through layer and channels of the network. Cost reduction with compensation increases payoffs when applied by the manufacturer whose complementary products’ manufacturing costs are more distanced. It is also shown that retailers enjoy a retail advantage on one product at its best when playing retailer leading Stackelberg games.
Prognostic Impact of Adverse Pathologic Features in Sinonasal Squamous Cell Carcinoma
Authors: Parikh Anuraag S. , Fuller Jennifer C. , Lehmann Ashton E. , Goyal Neerav , Gray Stacey T. , Lin Derrick T.
Published: May 2020

Objective This study aimed to describe the impact of adverse clinical and pathologic features in sinonasal squamous cell carcinoma (SCC).

Design This study is designed with retrospective chart review.

Setting The present study is conducted at a tertiary care institution.

Participants All patients treated surgically for sinonasal SCC at our tertiary care institution between January 2006 and December 2013.

Main Outcome Measures Overall survival (OS) and disease free survival (DFS) are the final measurement of this study.

Results Forty-eight patients were identified. Mean age at surgery was 65.8 years, and mean follow-up time was 40.7 months. Eighteen patients (38%) had T1–T3 disease, while 30 patients (63%) had T4 disease. Seven patients (8.3%) had nodal disease at presentation. At 2, 5, and 10 years, OS was 71, 54, and 48%, respectively, while DFS was 64, 51, and 45%, respectively. Twelve patients (25%) experienced local recurrences with mean time to recurrence of 15.3 months. Twenty-five patients (52%) had positive margins, 24 (50%) had high-grade tumors, 18 (38%) had perineural invasion (PNI), and 15 (31%) had lymphovascular invasion (LVI). In the univariate analysis, T4 disease (risk ratio [RR] = 2.7) and high grade (RR = 2.4) had a significant association with DFS. In the multivariate analysis, high grade (RR = 4.0 and 4.5) and LVI (RR = 4.1 and 4.7) had a significant association with OS and DFS.

Conclusion Our single-institution experience of 48 patients suggests that high grade and LVI are independently associated with survival outcomes in sinonasal SCC, while PNI and microscopically positive margins do not have a significant impact.
Phage therapy as a potential solution in the fight against AMR: obstacles and possible futures
Authors: Brives Charlotte , Pourraz Jessica
Published: May 2020

Phage therapy, the use of bacteriophage viruses to treat bacterial infections, has existed for more than a hundred years. However, the practice is struggling to develop, despite growing support over the past 15 years from researchers and doctors, who see it as a promising therapy in the context of the rise of antimicrobial resistance (AMR). While the reasons for these developmental difficulties are complex, in this article we wish to address the effects of pharmaceutical regulations on phage therapy. By showing how phages are assimilated to an umpteenth antibiotic in legal texts, but also in certain medical practices, this article proposes to analyze the consequences of such regulatory categorization both for their production and the logistics of administration of proof of their efficacy in randomized controlled trials (RCTs), as well as the underlying concepts of infection and treatment. This paper follows Chandler’s work on the concept of antibiotics as infrastructure and its inversion presented by antimicrobial resistance. Phages as living, dynamic, evolving, and specific entities, do not lend themselves easily to current categories, norms, and development models. In this sense, they act as disruptors, revealing the limitations imposed by the existing infrastructure. More precisely here, and to continue Chandler’s initial thought process, this paper aims to show that antibiotics also form a kind of epistemological infrastructure, which acts as a powerful inhibitor to the development of phage therapy. In this sense antibiotics prevent the development of solutions to the problem they contribute to create. But the difficulties phage therapy faces, as highlighted in this article, can be interpreted as entry points for thinking of another medicine and imagining other possible futures. This analysis is based on a 3-year fieldwork study (2016–2019) in Europe (France, Belgium, and Switzerland), during which we conducted semi-directed interviews with various phage therapy stakeholders (physicians, researchers, pharmacists, regulators, patients, and patient associations), participatory observation in labs and observations during symposia and workshops on phages and phage therapy.
Raman compression of laser pulses without frequency modulation in plasma created in front of the seed pulse
Authors: Balakin A. A. , Fraiman G. M. , Levin D. S. , Skobelev S. A.
Published: May 2020

The possibility of suppressing effectively parasitic Raman amplification of plasma noise by creating a plasma in front of the seed pulse is studied. Such plasma can be created by injecting an additional ionizing laser pulse co-directionally with seed one and slightly ahead of it. It is shown that the efficiency of Raman amplification and compression will be high (about 80% of pump energy), if a delay between the ionization front and the seed laser pulse is less than or equal to two inverse increments of the Raman amplification. This conclusion is valid for both high and low plasma densities, when the nonlinear frequency shift due to the nonlinear dispersion of the plasma wave is significant. This result is confirmed by three-dimensional numerical simulations.
Bamboo-joint-like platforms for fast, long-distance, directional, and spontaneous transport of fluids
Authors: Wang Zeming , Lu Yao , Huang Shuai , Yin Shaohui , Chen Fengjun
Published: May 2020

Spontaneous transport of fluids without external force offers an enabling tool for a wide spectrum of fields. However, the development of a universal spontaneous transport platform for liquids remains a challenge. In this work, a novel bamboo-joint-like platform with tapered micro-tubes as transport units is presented, which not only enables the spontaneous transport and extrusion of liquids but also enables customized and optional assembly of transport devices. Spontaneous transport characterized with long-distance, anti-gravity transport, directional transport, and liquid extrusion characteristics was found to show excellent transport capacity. The results indicated that both transport distance and speed varied periodically with time, which was mainly due to the difference in curvature caused by asymmetric structure and capillary force. The desired spontaneous transportation was successfully obtained even when the supply rate speed was up to 632.5 μl/min and length of platform reached a scale of hundreds of millimeters. Transport units were easily fabricated via a commercially available 3D printing technique, so that the customized and directional spontaneous directional transport can be realized for liquid distribution, serpentine loop transportation, and speed control. With the comprehensive use of transport units and connectors, it is very easy to implement self-service construction of a universal complex multi-functional transportation platform.
Experimental evidence of absolute bandgaps in phononic crystal pipes
Authors: Plisson Jules , Pelat Adrien , Gautier François , Garcia Vicente Romero , Bourdon Thierry
Published: May 2020

The vibration filtering properties of a phononic crystal pipe whose unit cell consists of two segments of different materials and cross sections are studied numerically and experimentally. Such an architected bi-material pipe leads to the alignment of the dispersion branches in the same frequency ranges for all types of waves (flexural, longitudinal, and torsional), leading to an absolute bandgap. Each motion is studied by a 1D model in which the propagation of Floquet–Bloch waves in lossy media is considered. Numerical optimization is based on the simplex algorithm and aims to control both the central frequency and the bandwidth of the absolute bandgap on a selected target. Experimental characterization of a demonstrator confirms the filtering effects due to partial and absolute bandgaps even in the presence of quite high structural damping.
Role of intermediate 4f states in tuning the band structure of high entropy oxides
Authors: Sarkar Abhishek , Eggert Benedikt , Velasco Leonardo , Mu Xiaoke , Lill Johanna , Ollefs Katharina , Bhattacharya Subramshu S. , Wende Heiko , Kruk Robert , Brand Richard A. , Hahn Horst
Published: May 2020

High entropy oxides (HEOs) are single-phase solid solutions consisting of 5 or more cations in approximately equiatomic proportions. In this study, we show the reversible control of optical properties in a rare-earth (RE) based HEO-(Ce0.2La0.2Pr0.2Sm0.2Y0.2)O2−δ and subsequently utilize a combination of spectroscopic techniques to derive the features of the electronic band structure underpinning the observed optical phenomena. Heat treatment of the HEO under a vacuum atmosphere followed by reheat treatment in air results in a reversible change in the bandgap energy, from 1.9 eV to 2.5 eV. The finding is consistent with the reversible changes in the oxidation state and related f-orbital occupancy of Pr. However, no pertinent changes in the phase composition or crystal structure are observed upon the vacuum heat treatment. Furthermore, annealing of this HEO under a H2 atmosphere, followed by reheat treatment in air, results in even larger but still a reversible change in the bandgap energy from 1.9 eV to 3.2 eV. This is accompanied by a disorder–order type crystal structure transition and changes in the O 2p–RE 5d hybridization evidenced from x-ray absorption near-edge spectra (XANES). The O K and RE M4,5/L3 XANES indicate that the presence of Ce and Pr (in 3+/4+ states) leads to the formation of intermediate 4f energy levels between the O 2p and the RE 5d gap in HEO. It is concluded that heat treatment under reducing/oxidizing atmospheres affects these intermediate levels, thus offering the possibility to tune the bandgap energy in HEOs.
Nonlinear dynamics of thin liquid films subjected to mixed-frequency electrical field
Authors: Duruk Selin
Published: May 2020

The nonlinear dynamics of the interface between both perfect and leaky dielectric liquid films, interposed between two parallel electrodes, are investigated under the effect of mixed-frequency electric fields. A coupled system of evolution equations is derived in dimensionless form, by employing the long-wave approximation. The linear stability analysis is implemented in accordance with the characteristics of each specific case, namely, the constant (DC) and the altering (AC) fields. In particular, the response of the system to the multi-mode AC electrical field is analyzed. Assisted by the conclusions of the theoretical investigation, the initial-boundary-value problem associated with the coupled system of evolution equations is solved numerically for several parameter sets. The system behavior is studied by monitoring the evolution process and by examining the steady/quasi-steady pillar formations in the nonlinear regime. The possibility to generate interface profiles of diverse topological forms, to manipulate their features, and to control the time dependent progress and the film rupture by imposing different combinations of frequencies and/or amplitudes of the corresponding mode is confirmed.
Universities overcome bumps in transition to online teaching
Authors: Feder Toni
Published: May 2020

Instructors grapple with how to administer exams that meaningfully assess students, suppress cheating, minimize anxiety, and preserve privacy.
COVID-19 pandemic modeling is fraught with uncertainties
Authors: Kramer David
Published: May 2020

Policymakers face a plethora of predictions on how the disease will proceed and when it might resurge.
Population genetic structure of Indo-West Pacific carcharhinid sharks: what do we know and where to from here?
Authors: Pember Brenton M. , Chaplin Jennifer A. , Loneragan Neil R. , Braccini Matias
Published: May 2020

The Carcharhinidae is one of the most at-risk shark families in the Indo-West Pacific (IWP), which is a global priority for the conservation of elasmobranchs. Of the 57 described species of carcharhinids, 43 are known from the IWP, where many are subject to high fishing pressure. Many of these species are also found outside this bioregion. Understanding the connectivity of individual species across their ranges is paramount to successful management of their fisheries. Studies of population genetic structure have been the mainstay for assessing connectivity. Here, we review 41 studies pertaining to the population genetic structure of 20 species of carcharhinid whose ranges include the IWP and for which relevant data are available. The genetic markers used range from microsatellite loci and small mitochondrial DNA sequences (375 to 4797bp) to genomic analyses. Overall, the population genetic structure for these carcharhinids was varied but patterns emerged according to the lifestyle of the species, with the greatest structure shown by species that are highly habitat dependent and the least structure shown by oceanic species. Experimental designs of the underlying studies have, however, often been opportunistic with small sample sizes, few locations sampled and based on analysis of single mitochondrial regions and/or few microsatellite markers. The literature provides a basis for understanding the population genetic structure of IWP carcharhinids, but future research needs to focus on the application of population genomics and more robust experimental design so that population genetic structure can be quantified with higher certainty and resolution over finer spatial scales.
Ediacaran reorganization of the marine phosphorus cycle
Authors: Laakso Thomas A. , Sperling Erik A. , Johnston David T. , Knoll Andrew H.
Published: May 2020

Significance

The evolution of macroscopic animals in the latest Proterozoic Eon is associated with many changes in the geochemical environment, but the sequence of cause and effect remains a topic of intense research and debate. In this study, we use two apparently paradoxical observations—that massively phosphorus-rich rocks first appear at this time, and that the median P content of rocks does not change—to argue for a change in internal marine P cycling associated with rising sulfate levels. We argue that this change was self-sustaining, setting in motion a cascade of biogeochemical transformations that led to conditions favorable for major ecological and evolutionary change.
CXCL5-mediated recruitment of neutrophils into the peritoneal cavity of
Gdf15
-deficient mice protects against abdominal sepsis
Authors: Santos Isa , Colaço Henrique G. , Neves-Costa Ana , Seixas Elsa , Velho Tiago R. , Pedroso Dora , Barros André , Martins Rui , Carvalho Nuno , Payen Didier , Weis Sebastian , Yi Hyon-Seung , Shong Minho , Moita Luís F.
Published: May 2020

Significance

Sepsis remains a leading cause of death. New insights into its pathophysiology are likely to be key to the development of effective therapeutic strategies against sepsis. Given the role of GDF15 in metabolism regulation and in cachexia during late stages of cancer, features that also occur in sepsis, elucidation of the possible mechanistic role of GDF15 in sepsis is of great importance. We find that septic patients have very high levels of GDF15 in the peripheral blood, which correlate with clinical outcomes. Using
Gdf15
-deficient mice, we show that GDF15 plays a causal role in sepsis by delaying the local control of infection. These findings suggest GDF15 as a potential therapeutic target in sepsis secondary to a bacterial infection.
Spatial mapping of polymicrobial communities reveals a precise biogeography associated with human dental caries
Authors: Kim Dongyeop , Barraza Juan P. , Arthur Rodrigo A. , Hara Anderson , Lewis Karl , Liu Yuan , Scisci Elizabeth L. , Hajishengallis Evlambia , Whiteley Marvin , Koo Hyun
Published: May 2020

Significance

Dental caries remains an unresolved public health problem. The etiology is poorly understood, as the oral cavity harbors diverse communities of microorganisms. Using multiple imaging modalities on human teeth from patients with caries, we discovered a microbial community precisely arranged in a corona-like architecture. Moreover, this organization is mediated by the pathogen
Streptococcus mutans
through production of an extracellular scaffold that directs positioning of other oral microbes. We developed a methodology to quantify the spatial structure of microbial communities at the micron scale and found a precise spatial patterning of bacteria associated with localized caries onset. These findings are relevant as we approach the post-microbiome era, whereby quantifying the community structural organization may be essential for understanding microbiome function.