bluuebunny/crossref_metadata_2025 huggingface dataset:
The eccentric millisecond pulsar, PSR J0955−6150
Authors: Serylak M. , Venkatraman Krishnan V. , Freire P. C. C. , Tauris T. M. , Kramer M. , Geyer M. , Parthasarathy A. , Bailes M. , Bernadich M. C. i , Buchner S. , Burgay M. , Camilo F. , Karastergiou A. , Lower M. E. , Possenti A. , Reardon D. J. , Shannon R. M. , Spiewak R. , Stairs I. H. , van Straten W.
Published: May 2022

Context.PSR J0955−6150 is a member of an enigmatic class of eccentric millisecond pulsar (MSP) and helium white dwarf (He WD) systems (eMSPs), whose binary evolution is poorly understood and believed to be strikingly different to that of traditional MSP+He WD systems in circular orbits.

Aims.Measuring the masses of the stars in this system is important for testing the different hypotheses for the formation of eMSPs.

Methods.We carried out timing observations of this pulsar with the Parkes radio telescope using the 20 cm multibeam and ultra-wide bandwidth low-frequency (UWL) receivers, and theL-band receiver of the MeerKAT radio telescope. The pulse profiles were flux and polarisation calibrated, and a rotating-vector model (RVM) was fitted to the position angle of the linear polarisation of the combined MeerKAT data. Pulse times of arrival (ToAs) were obtained from these using standard pulsar analysis techniques and analysed using theTEMPO2 timing software.

Results.Our observations reveal a strong frequency evolution of this MSP’s intensity, with a flux density spectral index (α) of −3.13(2). The improved sensitivity of MeerKAT resulted in a greater than tenfold improvement in the timing precision obtained compared to our older Parkes observations. This, combined with the eight-year timing baseline, has allowed precise measurements of a very small proper motion and three orbital post-Keplerian parameters, namely the rate of advance of periastron,ω̇ = 0.00152(1) deg yr−1, and the orthometric Shapiro delay parameters,h3 = 0.89(7) μs and ς = 0.88(2). Assuming general relativity, we obtainMp = 1.71(2) M⊙for the mass of the pulsar andMc = 0.254(2) M⊙for the mass of the companion; the orbital inclination is 83.2(4) degrees. Crucially, assuming that the position angle of the linear polarisation follows the RVM, we find that the spin axis has a misalignment relative to the orbital angular momentum of > 4.8deg at 99% confidence level.

Conclusions.While the value ofMpfalls well within the wide range observed in eMSPs,Mcis significantly smaller than expected from several formation hypotheses proposed, which are therefore unlikely to be correct and can be ruled out;Mcis also significantly different from the expected value for an ideal low mass X-ray binary evolution scenario. If the misalignment between the spin axis of the pulsar and the orbital angular momentum is to be believed, it suggests that the unknown process that created the orbital eccentricity of the binary was also capable of changing its orbital orientation, an important evidence for understanding the origin of eMSPs.
Exoplanet cartography using convolutional neural networks
Authors: Meinke K. , Stam D. M. , Visser P. M.
Published: May 2022

Context. In the near future, dedicated telescopes will observe Earth-like exoplanets in reflected parent starlight, allowing their physical characterization. Because of the huge distances, every exoplanet will remain an unresolved, single pixel, but temporal variations in the pixel’s spectral flux contain information about the planet’s surface and atmosphere.

Aims. We tested convolutional neural networks for retrieving a planet’s rotation axis, surface, and cloud map from simulated single-pixel observations of flux and polarization light curves. We investigated the influence of assuming that the reflection by the planets is Lambertian in the retrieval while in reality their reflection is bidirectional, and the influence of including polarization.

Methods. We simulated observations along a planet’s orbit using a radiative transfer algorithm that includes polarization and bidirectional reflection by vegetation, deserts, oceans, water clouds, and Rayleigh scattering in six spectral bands from 400 to 800 nm, at various levels of photon noise. The surface types and cloud patterns of the facets covering a model planet are based on probability distributions. Our networks were trained with simulated observations of millions of planets before retrieving maps of test planets.

Results. The neural networks can constrain rotation axes with a mean squared error (MSE) as small as 0.0097, depending on the orbital inclination. On a bidirectionally reflecting planet, 92% of ocean facets and 85% of vegetation, deserts, and cloud facets are correctly retrieved, in the absence of noise. With realistic amounts of noise, it should still be possible to retrieve the main map features with a dedicated telescope. Except for face-on orbits, a network trained with Lambertian reflecting planets yields significant retrieval errors when given observations of bidirectionally reflecting planets, in particular, brightness artifacts around a planet’s pole. Including polarization improves the retrieval of the rotation axis and the accuracy of the retrieval of ocean and cloudy map facets.
O’TRAIN: A robust and flexible ‘real or bogus’ classifier for the study of the optical transient sky
Authors: Makhlouf K. , Turpin D. , Corre D. , Karpov S. , Kann D. A. , Klotz A.
Published: May 2022

Context. Scientific interest in studying high-energy transient phenomena in the Universe has risen sharply over the last decade. At present, multiple ground-based survey projects have emerged to continuously monitor the optical (and multi-messenger) transient sky at higher image cadences and covering ever larger portions of the sky every night. These novel approaches are leading to a substantial increase in global alert rates, which need to be handled with care, especially with regard to keeping the level of false alarms as low as possible. Therefore, the standard transient detection pipelines previously designed for narrow field-of-view instruments must now integrate more sophisticated tools to deal with the growing number and diversity of alerts and false alarms.

Aims. Deep machine learning algorithms have now proven their efficiency in recognising patterns in images. These methods are now used in astrophysics to perform different classification tasks such as identifying bogus from real transient point-like sources. We explore this method to provide a robust and flexible algorithm that could be included in any kind of transient detection pipeline.

Methods. We built a convolutional neural network (CNN) algorithm in order to perform a ‘real or bogus’ classification task on transient candidate cutouts (subtraction residuals) provided by different kinds of optical telescopes. The training involved human-supervised labelling of the cutouts, which are split into two balanced data sets with ‘true’ and ‘false’ point-like source candidates. We tested our CNN model on the candidates produced by two different transient detection pipelines. In addition, we made use of several diagnostic tools to evaluate the classification performance of our CNN models.

Results. We show that our CNN algorithm can be successfully trained on a large and diverse array of images on very different pixel scales. In this training process, we did not detect any strong over- or underfitting with the requirement of providing cutouts with a limited size no larger than 50 × 50 pixels. Tested on optical images from four different telescopes and utilising two different transient detection pipelines, our CNN model provides a robust ‘real or bogus’ classification performance accuracy from 93% up to 98% for well-classified candidates.
Comparison of the star formation in X-ray-selected AGN in eFEDS with that of star-forming galaxies
Authors: Mountrichas G. , Buat V. , Yang G. , Boquien M. , Burgarella D. , Ciesla L. , Malek K. , Shirley R.
Published: May 2022

We use approximately 1800 X-ray active galactic nuclei (AGN) in the eROSITA Final Equatorial-Depth Survey (eFEDS) that span over two orders of magnitude in X-ray luminosity, LX, 2−10 keV ≈ 1043−45 erg s−1, and compare their star-formation rate (SFR) to that of non-AGN star-forming systems, at 0.5 < z < 1.5. To this end, we compiled a reference galaxy catalogue of about 17 000 sources. Both samples have the same photometric coverage, from optical to far-infrared. We construct the spectral energy distributions (SEDs) of all sources and fit them using the CIGALE code, using the same templates and parametric grid for both samples, and accounting for the mass incompleteness and exclude quiescent systems from both datasets. This allows us to compare the SFR of the two populations in a uniform manner, minimising systematic effects. Based on our analysis, AGN at low and moderate LX (LX, 2−10 keV < 1044 erg s−1) have SFR that is lower than, or at most equal to, that of star-forming galaxies, in agreement with previous studies. The large number of luminous X-ray AGN available in the eFEDS dataset enable us to expand our investigations at higher LX to test previous, tentative results. At LX, 2−10 keV > 1044.2 erg s−1, the SFR of AGN appears enhanced by ∼30% compared to that of star-forming sources, for systems with stellar mass in the range of 10.5 < log [M*(M⊙)] < 11.5, confirming indications found in previous studies. The most massive sources, log [M*(M⊙)] > 11.5, present a flat SFRnorm–LX relation up to LX, 2−10 keV ∼ 1044.5 erg s−1, with SFR similar to that of star-forming galaxies. However, at higher LX (LX, 2−10 keV ∼ 1045 erg s−1), we find indications that the SFR of these massive AGN hosts may be enhanced compared to that of non-AGN systems.
The dusty heart of Circinus
Authors: Isbell J. W. , Meisenheimer K. , Pott J.-U. , Stalevski M. , Tristram K. R. W. , Sanchez-Bermudez J. , Hofmann K.-H. , Gámez Rosas V. , Jaffe W. , Burtscher L. , Leftley J. , Petrov R. , Lopez B. , Henning T. , Weigelt G. , Allouche F. , Berio P. , Bettonvil F. , Cruzalebes P. , Dominik C. , Heininger M. , Hogerheijde M. , Lagarde S. , Lehmitz M. , Matter A. , Meilland A. , Millour F. , Robbe-Dubois S. , Schertl D. , van Boekel R. , Varga J. , Woillez J.
Published: May 2022

Context.Active galactic nuclei play a key role in the evolution of galaxies, but their inner workings and physical connection to the host are poorly understood due to a lack of angular resolution. Infrared interferometry makes it possible to resolve the circumnuclear dust in the nearby Seyfert 2 galaxy, the Circinus Galaxy. Previous observations have revealed complex structures and polar dust emission but interpretation was limited to simple models. The new Multi AperTure mid-Infrared Spectro-Scopic Experiment (MATISSE) makes it possible to image these structures for the first time.

Aims.We aim to precisely map the morphology and temperature of the dust surrounding the supermassive black hole through interferometric imaging.

Methods.We observed the Circinus Galaxy with MATISSE at the Very Large Telescope Interferometer (VLTI), producing 150 correlated flux spectra and 100 closure phase spectra. The novel inclusion of closure phases makes interferometric imaging possible for the first time. We reconstructed images in theN-band at ∼10 mas resolution. We fit blackbody functions with dust extinction to several aperture-extracted fluxes from the images to produce a temperature distribution of central dusty structures.

Results.We find significant substructure in the circumnuclear dust: central unresolved flux of ∼0.5 Jy, a thin disk 1.9 pc in diameter oriented along ∼45°, and a ∼4 × 1.5 pc polar emission extending orthogonal to the disk. The polar emission exhibits patchiness, which we attribute to clumpy dust. Flux enhancements to the east and west of the disk are seen for the first time. We distinguish the temperature profiles of the disk and of the polar emission: the disk shows a steep temperature gradient indicative of denser material; the polar profile is flatter, indicating clumpiness and/or lower dust density. The unresolved flux is fitted with a high temperature, ∼370 K. The polar dust remains warm (∼200 K) out to 1.5 pc from the disk. We attribute approximately 60% of the 12 μm flux to the polar dust, 10% to the disk, and 6% is unresolved; the remaining flux was resolved out. The recovered morphology and temperature distribution resembles modeling of accretion disks with radiation-driven winds at large scales, but we placed new constraints on the subparsec dust.

Conclusions.The spatially resolved subparsec features imaged here place new constraints on the physical modeling of circumnuclear dust in active galaxies; we show strong evidence that the polar emission consists of dust clumps or filaments. The dynamics of the structures and their role in the Unified Model remain to be explored.
Controllability problems for the heat equation with variable coefficients on a half-axis
Authors: Fardigola Larissa , Khalina Kateryna
Published: May 2022

In the paper, the problems of controllability and approximate controllability are studied for the heat equation wt = 1/ρ (kwx)x + γw, x > 0, t ∈ (0, T), controlled by the Dirichlet boundary condition. Control is considered in L∞(0, T). It is proved that each initial state of this system is approximately controllable to any its end state in a given time T > 0.
Interpretation of Stark broadening measurements on a spatially integrated plasma spectral line
Authors: Thouin Julien , Benmouffok Malyk , Freton Pierre , Gonzalez Jean-Jacques
Published: May 2022

In thermal plasma spectroscopy, Stark broadening measurement of hydrogen spectral lines is considered to be a good and reliable measurement for electron density. Unlike intensity based measurements, Stark broadening measurements can pose a problem of interpretation when the light collected is the result of a spatial integration. Indeed, when assuming no self-absorption of the emission lines, intensities simply add up but broadenings do not. In order to better understand the results of Stark broadening measurements on our thermal plasma which has an unneglectable thickness, a Python code has been developed based on local thermodynamic equilibrium (LTE) assumption and calculated plasma composition and properties. This code generates a simulated pseudo experimental (PE) H
α
spectral line resulting from an integration over the plasma thickness in a selected direction for a given temperature profile. The electron density was obtained using the Stark broadening of the PE spectral line for different temperature profiles. It resulted that this measurement is governed by the maximum electron density profile up until the temperature maximum exceeds that of the maximum electron density. The electron density obtained by broadening measurement is 70–80% of the maximum electron density.
A bi-objective humanitarian logistics model considering equity in the affected zones: application to a recent earthquake in Mexico
Authors: Hernández-Leandro Norberto A. , Ibarra-Rojas Omar , Camacho-Vallejo José-Fernando
Published: May 2022

In this paper, we propose a bi-objective program to model a post-disaster strategical decision problem. We consider the situation after a catastrophic disaster occurred, in which temporary distribution centers must be located. The distribution centers consolidate aid to be delivered to affected people. We assume that affected people go to collect needed aid from temporary located distribution centers. Hence, a predefined mobility radius is considered, that indicates the distance that people are willing to travel to receive aid. Additionally, needed aid required by affected individuals is consolidated in an affected demand zone and equity constraints are included to balance the aid given to those affected zones. One objective of the proposed model is to minimize the time employed by demand zones to collect aid. In humanitarian logistics it is common that the decision maker is associated with either government or non-profit organizations that are in charge of relief. Usually, there is a limited budget to conduct the operations. Hence, the decision maker also aims to minimize the cost of locating temporary distribution centers. Both objectives are simultaneously considered. Hence, to obtain efficient solutions of this bi-objective problem, an exact AUGMECON method is proposed, which is an improved version of the classic ε-constraint method for multi-objective optimization. To overcome with the computational limitations shown by the exact method, a genetic algorithm is also designed and used to approximate the Pareto front. To conduct the computational experience, a case study and additional random instances are considered. The case study is based on an earthquake that recently occurred in Mexico. The results obtained by both implemented methods are compared by using different well-known metrics, such as, the number of solutions, the k-distance, the size of the space covered, and a coverage measure. It is shown that, on average, the proposed genetic algorithm outperforms the AUGMECON when comparing the quality of the obtained Pareto fronts. Results offer the possibility for the decision maker to prioritize either time or cost when locating temporary distribution centers in a catastrophic situation.
Institutionalized democracy and the shadow economy in the short- and long-run: empirical analysis from Uganda
Authors: Esaku Stephen
Published: May 2022

This paper investigates the relationship between institutionalized democracy and the shadow economy in both the long- and short-run. Using time series data from Uganda that cover the period from 1991 to 2015, this paper applies autoregressive distributed lag method to investigate this relationship. How democracy affects the shadow economy in less developed countries like Uganda is not well understood. This paper aims to fill the above knowledge gap. The findings show that the shadow economy and institutionalized democracy are negatively correlated in both the short- and long-run. This implies that improvement in institutionalized democracy significantly hinders the rise of shadow activities. This indicates that institutions regulate the conduct of economic agents and determine how entrepreneurs engage in economic activities. Moreover, institutions are crucial in resource allocation which in turn leads to welfare improvement. Improvement in welfare of citizens reduces their incentive to engage in informal sector activities since the formal sector provides the necessary support needed to operate legally. These findings are robust to alternative econometric methods. Two practical implications of these findings stand out. First, these findings indicate that reforming the governance system to facilitate efficient resource allocation could be one way of addressing widespread informality in developing economies. Second, these results also indicate that minimizing informality in the economy should gradually move away from emphasis on tackling proximate causes of informality to democratic reforms that change the authority patterns. In this case institutionalized democracy is another important channel of mitigating the rise of the shadow economy.
Measurement of total electron emission yield of insulators based on self-terminating charge neutralization
Authors: Cai Yahui , Wang Dan , Qi Kangcheng , He Yongning
Published: May 2022

For insulators, the accumulated charge on the surface after electron bombardment will interfere with the total electron emission yield (TEEY) measurement. This work develops a novel method to automatically measure the TEEY of insulators based on self-terminating charge neutralization using two neutralization electron guns. We perform theoretical analysis and experimental design for the neutralization of positive and negative charges. Positive charges are neutralized by an electron gun whose cathode is equipotential to the sample. Negative charges are neutralized by another electron gun whose cathode is adjusted to a negative potential with respect to the grounded sample, which is set between EP1/e and EP2/e. We test the control and stability performance of the TEEY measurement system based on the timing design of the electron gun switching and believe that it meets the TEEY measurement requirements. The TEEY measurements of glass, Si, and SiO2 are in good agreement with the data reported in the references, which validates the accuracy of our method in this work. We anticipate that our method provides an essential reference for the rapid TEEY measurements of insulators.
Dynamic stability of electric power grids: Tracking the interplay of the network structure, transmission losses, and voltage dynamics
Authors: Böttcher Philipp C. , Witthaut Dirk , Rydin Gorjão Leonardo
Published: May 2022

Dynamic stability is imperative for the operation of the electric power system. This article provides analytical results and effective stability criteria focusing on the interplay of network structures and the local dynamics of synchronous machines. The results are based on an extensive linear stability analysis of the third-order model for synchronous machines, comprising the classical power-swing equations and the voltage dynamics. The article addresses the impact of Ohmic losses, which are important in distribution and microgrids but often neglected in analytical studies. We compute the shift of the stability boundaries to leading order, and thus provide a detailed qualitative picture of the impact of Ohmic losses. A subsequent numerical study of the criteria is presented, without and with resistive terms, to test how tight the derived analytical results are.
Characteristic effect of wall elasticity on flow instability and wall shear stress of a full-scale, patient-specific aneurysm model in the middle cerebral artery: An experimental approach
Authors: Yamaguchi Ryuhei , Tanaka Gaku , Shafii Nadia Shaira , Osman Kahar , Shimizu Yasutomo , Saqr Khalid M. , Ohta Makoto
Published: May 2022

The mechanisms underlying the growth and rupture of aneurysms are poorly understood. Although the wall shear stress (WSS) in elastic aneurysm models is examined using fluid-structure interaction (FSI) simulations, it has not been sufficiently validated using experimental modalities, such as particle image velocimetry (PIV) or phase contrast magnetic resonance imaging (PC-MRI). In this study, we investigated pulsatile flow in an elastic, image-based, patient-specific cerebral aneurysm model using PIV. The phantom model was carefully fabricated using a specialized technique by silicone elastomer. We explored the hemodynamics of the WSS and the kinetic energy cascade (KEC) in the elastic model compared with a rigid model, at the apex of the bifurcation of the middle cerebral artery (MCA) in vitro. The effects of elasticity on the WSS, WSS gradient (WSSG), and tensile strength of the aneurysm wall were also investigated, in addition to the effect of wall elasticity on the KEC compared to a rigid wall. Although the WSSG around the stagnation point had a large positive value, there was no difference between the two models. In particular, wall elasticity suppressed the WSS magnitude around the stagnation point and attenuated the KEC (i.e., the flow fluctuation). Future studies examining KEC frequency and WSS characteristics in a phantom model should consider assessing elasticity.
Penetration and aerosolization of cough droplet spray through face masks: A unique pathway of transmission of infection
Authors: Vadlamudi Gautham , Thirumalaikumaran S. K. , Chakravortty Dipshikha , Saha Abhishek , Basu Saptarshi
Published: May 2022

The advent of the COVID-19 pandemic has necessitated the use of face masks, making them an integral part of the daily routine. Face masks occlude the infectious droplets during any respiratory event contributing to source control. In the current study, spray impingement experiments were conducted on porous surfaces like masks having a different porosity, pore size, and thickness. The spray mimics actual cough or a mild sneeze with respect to the droplet size distribution (20–500 μm) and velocity scale (0–14 m/s), which makes the experimental findings physiologically realistic. The penetration dynamics through the mask showed that droplets of all sizes beyond a critical velocity penetrate through the mask fabric and atomize into daughter droplets in the aerosolization range, leading to harmful effects due to the extended airborne lifetime of aerosols. By incorporating spray characteristics along with surface tension and viscous dissipation of the fluid passing through the mask, multi-step penetration criteria have been formulated. The daughter droplet size and velocity distribution after atomizing through multi-layered masks and its effects have been discussed. Moreover, the virus-emulating particle-laden surrogate respiratory droplets are used in impingement experiments to study the filtration and entrapment of virus-like nanoparticles in the mask. Furthermore, the efficacy of the mask from the perspective of a susceptible person has been investigated.
Improved native understorey establishment in mine waste rock in Australia’s wet–dry tropics
Authors: Parry Megan L. , Bellairs Sean M. , Lu Ping
Published: May 2022

Re-establishment of understorey in mine waste can be challenging because of its physical, chemical and microbiological characteristics. This project investigated amelioration treatments for establishing native understorey in waste rock at Ranger uranium mine, including the addition of fine sand, fertiliser, surface litter, incorporated organic matter, or a combination of sand, fertiliser and litter. Trials were established in a shade house and in situ on a waste-rock landform. Several grass and legume species had seedling emergence and growth being monitored. In situ, surface litter generally had twice as many seedlings emerge as did the other treatments and had the tallest mean height for most species, likely because it created a microclimate that retained moisture and moderated temperature. In the shade house, no treatment had significantly greater emergence than the control (except Acacia gonocarpa F.Muell. with surface litter). Fertiliser application resulted in significantly taller plants in the shade house but had no effect in situ, which suggests that under well watered conditions, plant growth in waste rock is affected by nutrient deficiency, whereas in field conditions, water supply is the main growth-limiting factor. When establishing native understorey on waste rock in hot and seasonally wet–dry climates, applying surface litter with seeds may improve initial establishment.
Transcriptome analysis of maize pollen grains under drought stress during flowering
Authors: Zhang Yinping , Soualihou Soualiou , Li Juan , Xu Yonghan , Rose Ray J. , Ruan Yong-Ling , Li Jincai , Song Youhong
Published: May 2022

Drought stress is detrimental to male reproduction in maize (Zea mays L.), largely through reducing the quantity and quality of pollen grains. However, transcriptional response of maize pollen grains to drought stress has not been well documented. We compared pollen gene expression for a maize hybrid (ZhongDan909) under well-watered and drought-stress conditions, based on RNA-Seq validated by quantitative real-time PCR analysis. Expression of 6424 genes and 1302 transcripts was altered in pollen grains of maize subjected to 7 days of drought during flowering. Gene Ontology annotations showed 308 differentially expressed genes, annotated and classified into 50 primary functional categories. Kyoto Encyclopedia of Genes and Genomes analyses revealed 44 differentially expressed genes in nine metabolic pathways. In relation to carbohydrate metabolism pathways, there was downregulation of a polygalacturonase gene, which could reduce cell wall lysis in early pollen germination, and an increase in callose synthase transcripts along with reduced cellulase transcripts. These altered gene expressions responsible for cell wall integrity may inhibit the initiation of pollen tube growth. The onset of tube growth could be further impeded by observed changes in gene expression that potentially influence hormone metabolism (including downregulation of AUXIN RESPONSE FACTOR 18 and EIN3-BINDING F-BOX), reduce mitochondrial function, and alter protein translation. Genes with potential roles in adaptation were also altered in their transcript levels. These included genes encoding the upregulated transcription factor ZmNF-YC2, and the downregulated ZmbHLH13, a negative regulator of jasmonic acid responses. The upregulated flavin enzyme gene DIHYDROLIPOYL DEHYDROGENASE 1, associated with increased levels of reactive oxygen species, is of interest in relating redox homeostasis to stress adaptation. Overall, the analyses identified a suite of genes involved in the development of pollen grains and tubes and responsive to drought stress. The findings enhance understanding of the gene networks underlying compromised pollen viability under drought stress.
Full adoption of the most effective strategies to mitigate methane emissions by ruminants can help meet the 1.5 °C target by 2030 but not 2050
Authors: Arndt Claudia , Hristov Alexander N. , Price William J. , McClelland Shelby C. , Pelaez Amalia M. , Cueva Sergio F. , Oh Joonpyo , Dijkstra Jan , Bannink André , Bayat Ali R. , Crompton Les A. , Eugène Maguy A. , Enahoro Dolapo , Kebreab Ermias , Kreuzer Michael , McGee Mark , Martin Cécile , Newbold Charles J. , Reynolds Christopher K. , Schwarm Angela , Shingfield Kevin J. , Veneman Jolien B. , Yáñez-Ruiz David R. , Yu Zhongtang
Published: May 2022

Significance

Agricultural methane emissions must be decreased by 11 to 30% of the 2010 level by 2030 and by 24 to 47% by 2050 to meet the 1.5 °C target. We identified three strategies to decrease product-based methane emissions while increasing animal productivity and five strategies to decrease absolute methane emissions without reducing animal productivity. Globally, 100% adoption of the most effective product-based and absolute methane emission mitigation strategy can meet the 1.5 °C target by 2030 but not 2050, because mitigation effects are offset by projected increases in methane. On a regional level, Europe but not Africa may be able to meet their contribution to the 1.5 °C target, highlighting the different challenges faced by high- and middle- and low-income countries.
VMP1 and TMEM41B are essential for DMV formation during β-coronavirus infection
Authors: Ji Mingming , Li Meng , Sun Long , Zhao Hongyu , Li Ying , Zhou Lulu , Yang Zhenni , Zhao Xin , Qu Wenyan , Xue Hanbing , Zheng Ze , Li Yiming , Deng Hongyu , Zhao Yan G.
Published: May 2022

β-coronaviruses reshape host cell endomembranes to form double-membrane vesicles (DMVs) for genome replication and transcription. Ectopically expressed viral nonstructural proteins nsp3 and nsp4 interact to zipper and bend the ER for DMV biogenesis. Genome-wide screens revealed the autophagy proteins VMP1 and TMEM41B as important host factors for SARS-CoV-2 infection. Here, we demonstrated that DMV biogenesis, induced by virus infection or expression of nsp3/4, is impaired in the VMP1 KO or TMEM41B KO cells. In VMP1 KO cells, the nsp3/4 complex forms normally, but the zippered ER fails to close into DMVs. In TMEM41B KO cells, the nsp3–nsp4 interaction is reduced and DMV formation is suppressed. Thus, VMP1 and TMEM41B function at different steps during DMV formation. VMP1 was shown to regulate cross-membrane phosphatidylserine (PS) distribution. Inhibiting PS synthesis partially rescues the DMV defects in VMP1 KO cells, suggesting that PS participates in DMV formation. We provide molecular insights into the collaboration of host factors with viral proteins to remodel host organelles.
Information geometry, Pythagorean-theorem extension, and Euclidean distance behind optical sensing via spectral analysis
Authors: Zheltikov A M
Published: May 2022

We present an information-geometric perspective on a generic spectral-analysis task pertaining to a vast class of optical measurements in which a parameter θ needs to be evaluated from θ-dependent spectral features in a measurable optical readout. We show that the spectral shift and line broadening driven by small Δθ variations can be isolated as orthogonal components in a Pythagorean-theorem extension for a Euclidean distance in the space of probability distributions, representing the Δθ-induced information gain, expressible via the relative entropy and the pertinent Fisher information. This result offers important insights into the limits of optical signal analysis, as well as into the ultimate spectral resolution and the limiting sensitivity of a vast class of optical measurements. As one example, we derive a physically transparent closed-form analytical solution for the information-theory bound on the precision of all-optical temperature sensors based on color centers in diamond.
Near field radio link design in fat phantom for Wireless Capsule Endoscopy application
Authors: Kamaruddin Nur Amalina , Kamardin Kamilia , Yamada Yoshihide , Zainudin Norsiha , Arima Takuji , Michishita Naobumi , Takahashi Masaharu
Published: May 2022

Medical devices such as Wireless Capsule Endoscopy (WCE) that need wireless imaging and monitoring, operating at 402 MHz, is considered to be in the near field region due to the distance being shorter than the wavelength. In this paper, the radio link calculation method in the near field region is investigated. Normal Mode Helical Antenna (NMHA) is used as the transmitter antenna which is placed inside of a fat phantom of 11.6 F/m and the receiver antenna at distance 0.1 to 1.0 m apart. For link budget establishment, parameters such as power density, W and receiver antenna effective area, Ae
are investigated through electromagnetic simulation. The distance dependency of W is examined and the result of W∝ 1/(distance)2 is obtained. The relation of Ae
of the receiver antenna is found to be the size of the cross-section area of the antenna. A radio link equation is formed by employing W, Ae
and other propagation loss factors of a medium and is then compared with the power received, PR
and S21
obtained from simulation. The agreement between calculated and simulated results shows that this equation can be used in the near field region.
Biocompatible Sago Aerogel Material as A Substrate for Antenna Application
Authors: Adnan M A , Kamilia K , Yamada Y , Idris I H , Ali A A , Hamdan H.
Published: May 2022

This paper presents a patch antenna that operates at 2.4 GHz for body communication applications. New biocompatible material is proposed named Sago Aerogel is used as the antenna substrate. As a new substrate material is proposed, a simple patch antenna with a total size of substrate size of 60 mm × 66.2 mm × 1.6 mm size designed and simulated. The antenna performances in terms of S11 value, radiation pattern, gain, and input impedance are studied and discussed.
Focal Region Ray Tracing for Slanted Incident Rays on Spherical Reflector Antenna
Authors: Arjunaidi Ayuni Afiqah , Yamada Yoshihide , Kamardin Kamilia
Published: May 2022

Multi beam antenna system is required at base station for fifth-generation (5G) mobile communication and also to cover large portions of field of view for the satellite antenna. A spherical reflector antenna is promising to give high gain directivity of each independent beams for its multiple beam capabilities. The study of the feed elements system is carried out by analysing the focus of slanted incident rays in receiving mode from 0° to 30° at step angle 10°. Simple analytical equations are derived to find the incident and reflected rays. This focal region of spherical reflector is studied in MATLAB program. Accuracy of the MATLAB results are validated by examining the focal region using an electromagnetic simulator, FEKO. The locus of feed of spherical reflector antenna for certain angles of the incident rays are presented in this study.
Fabrication and characterisation of Frequency Selective Surface (FSS) for Terahertz Sensing Application
Authors: Ishak N S , Zainal N , Seman F C , Shah S M
Published: May 2022

A frequency selective surface (FSS) structure based on a circular slot with 28 to 31 μm was fabricated using Electron Beam Lithography combined with wet etching technique on a 400 μm thick quartz substrate. The circular slot pattern, designed using the CST software, was transferred during the Electron Beam (EBL) exposure with 100 kV voltage acceleration, 2 nA of e-beam current, and line dosage of 1000 μC2. A 0.5 μm thick aluminium layer was deposited on a quartz substrate using the thermal evaporator technique. The aluminium thickness was confirmed by laser microscope and surface profiler measurement. The investigation shows that 20 seconds is the optimal etching time for producing the desired FSS circular slot structure compared to 40 and 60 seconds. The fabricated samples surface metrology was examined using an optical microscope, Field Emission Scanning Electron Microscope (FESEM) and Atomic Force Microscope (AFM). The material compositions of the samples were confirmed by using the Energy Dispersive X-ray (EDX) measurement. Results show that, on average, there are ±1.5 μm of tolerance produced for fabricated sample size on the circular slot pattern compared to the CST simulation results. FSS performance slightly shifted in the frequency from actual 1.80 THz to 1.79 THz, whereas the transmission magnitude has increased by 0.03 from 0.91 to 0.94.
Near Field on Inductor Loops for Inductive Couple Fed Antenna
Authors: Azmi N Q , Murad N A , Samsuri N A , Tanvir A R , Nizam A A Z A
Published: May 2022

This paper presents an evaluation on the near field of square loop and circular loop for inductive couple fed RFID Tag antenna. The loop is simulated with different diameter and width The turns number (N) of the loop is varies up to three number of turns for each loop length. The magnetic fields and inductance are simulated to estimate the signal strength that can be coupled to the tag antenna. To evaluate the performance, the inductive feeding loop is designed to operate at RFID UHF band (860 MHz - 960 MHz) and simulated using CST software. It is confirmed that 6 mm loop length of the square and circular loop has higher magnetic field values as the surface area of the loop is bigger. The loop with different overall dimension gives out different reactance, inductance and magnetic field, dipole antenna, CST, and loop antenna.
Design of a Flexible T-Matched Feed UHF RFID Tag Antenna
Authors: Miswadi NF. , Abd Rahman NH , Subahir S. , Aris M.A. , Awang RA , Lim E.H.
Published: May 2022

A flexible radio frequency identification (RFID) tag antenna with a T-match feeder is proposed in this paper. The T-match feed acts as the conjugate network matching of the tag antenna and 0.99 of power transfer coefficient was achieved. By incorporating a meander line and capacitive tip loading technique, the compact size is realized with a wide bandwidth of 44MHz that can cover the RFID spectrum allocated for the Malaysia region, from 919 to 923 MHz. The proposed antenna is printed on the flexible polyethene terephthalate (PET) substrate with a dimension of 90mm × 24mm × 0.143mm. By employing 4W EIRP power, the detection distance of 29.15m in free space. The proposed meandered line and capacitive tip loading tag antenna with T-match feed line is beneficial to be part of the RFID systems because of their compactness, wide bandwidth and high-power transfer coefficient.
Utilizing Logistic Map to Enhance the Population Diversity of PSO
Authors: Ajibade S M , Chweya R , Ogunbolu M O , Fadipe S R
Published: May 2022

Particle swarm optimization (PSO) is a high-quality, nature-inspired global optimization algorithm that can be applied to a variety of real-world optimization problems. PSO, on the other hand, has some flaws, such as slow convergence, premature convergence, and the ability to become stuck at local optimum solutions. This research aims to address the issue of population diversity in the PSO search process, which leads to premature convergence. As a result, in this study, a method is introduced to PSO in order to avoid early stagnation, which leads to premature convergence. A chaotic dynamic weight particle swarm optimization (CTPSOA) is proposed, in which a chaotic logistic map is delivered to increase the population range within the PSO search technique by editing the inertia weight of PSO to avoid premature convergence. This study also looks into the overall performance and viability of the proposed CTPSOA as a set of function selection rules for solving optimization issues. There are eight traditional benchmark functions that are used to assess the overall results and obtain the accuracy of the proposed (CTPSOA) algorithms when compared to a few other meta-heuristics optimization rules. The test results reveal that the CTPSOA outperforms other meta-heuristics algorithms in solving optimization problems by 85% and has established itself as a reliable and superior metaheuristics algorithm for feature selection.
Galactic cosmic rays above the Earth’s atmosphere
Authors: Buchvarova Marusya
Published: May 2022

Galactic cosmic rays (GCRs) originate from sources outside the solar system and reach the Earth’s environment from all directions. More than 100 years after the first detection of cosmic rays, the origin of high-energy cosmic rays is still a mystery. Although our knowledge of the origin and propagation of cosmic rays is relatively limited, we can study the radiation conditions in the near-Earth space environment in more detail. The origin, composition, and energy spectra of cosmic rays are briefly discussed in this paper. A brief review of the transport of galactic cosmic rays in the heliosphere is given. The geomagnetic effects on galactic cosmic rays and the atmospheric interactions of primary particles are also discussed in the paper.
Extra-terrestrial influence on climate variability
Authors: Velichkova Ts P , Kilifarska N A
Published: May 2022

This study is focused on the analysis of signatures of extra-terrestrial influence on the centennial variability of some climatic variables, during the period 1900-2010. The applied lagged cross-correlation analysis shows evidence for a synchronisation between intensity of galactic cosmic rays (GCR) and two climate variables – the air surface temperature and the sea level pressure. The time delay of climatic response is not more than 5 years in the regions of stronger correlations. Moreover, the centennial variability of GCR is imprinted on the ozone mixing ratio at 70 hPa, suggesting its role of a mediator of GCR influence on climate. Having in mind the ozone’s capability to control the near tropopause temperature and humidity, we have suggested a mechanism describing the transmission of GCR signal from lower stratosphere, down to the Earth’s surface.
Impacts of large-scale refugee resettlement on LCLUC: Bidi Bidi refugee settlement, Uganda case study
Authors: Nakalembe Catherine , Zubkova Maria , Hall Joanne V , Argueta Fernanda , Giglio Louis
Published: May 2022

Uganda is the third-largest refugee-hosting country partly due to its open-door policy—deemed one of the most progressive. When new refugees arrive, refugee settlements are established rapidly, and irreversible changes to the landscape are inevitable. We utilize satellite data to map land cover (LC), land use, and burned area (BA) to assess their relationship in the context of large-scale refugee resettlement in Bidi Bidi—Uganda’s largest refugee settlement. We show inevitable dramatic changes in LC, e.g. built-up residential zones increased from 1.8% to 30%, while cropland increased from less than 0.7%–25.6% during our study period (2015–2019). In contrast, BA that affected more than 80% of the area was drastically reduced during the establishment phase (August–December 2017). Substantial reduction in BA was observed predominantly within the residential zones, but outside of the zones, BA was hardly affected by the arrival of refugees. Our study shows that these changes in LC and BA are mainly missing in the readily accessible satellite-derived data products, which impede assessment, planning, and implementation of humanitarian response programs. We discuss the importance of mapping at the appropriate spatial and temporal scales and the importance of context, sector, and geographic domain knowledge expertise in developing critical information products for informing programs to support vulnerable populations.
Study on flexural behavior of graphene oxide recycled concrete beams
Authors: Guo K , Yang Y Z , Zhou J H , Wu X Y
Published: May 2022

In order to study the flexural behavior of graphene oxide (GO) recycled concrete beams, 6 GO recycled concrete beams were studied, and observe its failure mode and process. The effects of GO content, oxygen content of GO and replacement rate of recycled aggregate on the flexural behavior of the test beams, including cracking load and ultimate load, concrete strain and steel strain, mid-span deflection, were analyzed. The test results show that the cracking load and ultimate load of recycled concrete beams with GO increase to a certain extent with the increase of GO content. And the higher the oxygen content of GO, the higher the ultimate bearing capacity of GO recycled concrete beams. With the increase of replacement rate of recycled aggregate, the cracking load and ultimate load of the test beams decrease.
The stone cantilevers rehabilitation of heritage buildings
Authors: Lapuste A V , Marton B
Published: May 2022

The aim of this article is to analyse multiple solutions for the stone cantilevers rehabilitation commonly found in heritage buildings. The stone cantilevers are arranged in the inner courtyards of historical buildings and ensure horizontal circulation. Throughout the article will analyse two categories of situations encountered in the rehabilitation practice: for the first situation the cantilever rehabilitation can be done after the stone plate demolition, and for the second situation the cantilever rehabilitation must be done without having the option of demolishing the flat plates. The difficulty of the intervention is given by the fact that the fixed ending restrain of the cantilever was ensured during the execution technology, the cantilever fixed in the masonry being ensured during the building of the wall. The rehabilitation of the stone cantilevers is conditioned by the fact that the fixed ending restrain point cannot be rebuild on the initial principles. This fact requires the adoption of rehabilitation principles based on a different approach to ensure the fixed end point. The proposed solutions solve both issues ensuring the required load capacity of the cantilever and ensuring the required level of fixed end restrain
Numerical studies regarding the behaviour a large span roof under seismic load when using anti-seismic devices
Authors: Mojolic C
Published: May 2022

The study presents the data obtained on a large span structure equipped with passive seismic isolators, placed at roof level, when subjected to multiple seismic loads. Three distinct passive isolation systems are taken into consideration to reduce the seismic response of the structure. The first case uses Friction Pendulum Systems (FP), the second uses a combination of High Damping Rubber Bearing (HDRB) and low friction pot-bearing systems, and the third implies the use of Lead Rubber Bearings (LRB) and low friction pot-bearing systems. Using seven sets of accelerograms, recorded and generated, the values for the main seismic response parameters are extracted in to underline the efficiency of the proposed systems. The results obtained in terms of natural vibration period, accelerations, bending moment, base shear are compared.
Flexible steel structures used for ski tunnels in Parang Mountains, Romania
Authors: Negrea D , Cazacu Ch
Published: May 2022

The main idea of this project was to create an access road for the tourists and also to improve the winter sports conditions, especially the ski, in the beautiful Parag Mountains. It was a very challenging project, as the road takes until 1600 m at alpine elevation. One of the structures was delivered and assembled in November 2019, in 3 weeks of hard weather conditions, with a 5 working men team.