bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of adding post‐workout microcurrent in males cross country athletes
Authors: Naclerio Fernando , Moreno‐Perez Diego , Seijo Marcos , Karsten Bettina , Larrosa Mar , García‐Merino Jose Ánge L. , Thirkell Jack , Larumbe‐Zabala Eneko
Published: December 2020

Post‐exercise microcurrent based treatments have shown to optimise exercise‐induced adaptations in athletes. We compared the effects of endurance training in combination with either, a microcurrent or a sham treatment, on endurance performance. Additionally, changes in body composition, post‐exercise lactate kinetics and perceived delayed onset of muscle soreness (DOMS) were determined. Eighteen males (32.8 ± 6.3 years) completed an 8‐week endurance training programme involving 5 to 6 workouts per week wearing a microcurrent (MIC, n=9) or a sham (SH, n=9) device for 3‐h post‐workout or in the morning during non‐training days. Measurements were conducted at pre‐ and post‐intervention. Compared to baseline, both groups increased (P < 0.01) maximal aerobic speed (MIC, pre = 17.6 ± 1.3 to post=18.3 ± 1.0; SH, pre=17.8 ± 1.5 to post = 18.3 ± 1.3 km.h−1) with no changes in O2peak. No interaction effect per group and time was observed (P=0.193). Although both groups increased (P < 0.05) trunk lean mass (MIC, pre=23.2 ± 2.7 to post=24.2 ± 2.0; SH, pre=23.4 ± 1.7 to post=24.3 ± 1.6 kg) only MIC decreased (pre=4.8 ± 1.5 to post=4.5 ± 1.5, p=0.029) lower body fat. At post‐intervention, no main differences between groups were observed for lactate kinetics over the 5 min recovery period. Only MIC decreased (P<0.05) DOMS at 24‐h and 48‐h, showing a significant average lower DOMS score over 72‐h after the completion of the exercise‐induced muscle soreness protocol. In conclusion, a 3‐h daily application of microcurrent over an 8‐week endurance training programme produced no further benefits on performance in endurance‐trained males. Nonetheless, the post‐workout microcurrent application promoted more desirable changes in body composition and attenuated the perception of DOMS over 72‐h post‐exercise.
Targeting transcriptional coregulator OCA-B/Pou2af1 blocks activated autoreactive T cells in the pancreas and type 1 diabetes
Authors: Kim Heejoo , Perovanovic Jelena , Shakya Arvind , Shen Zuolian , German Cody N. , Ibarra Andrea , Jafek Jillian L. , Lin Nai-Pin , Evavold Brian D. , Chou Danny H.-C. , Jensen Peter E. , He Xiao , Tantin Dean
Published: December 2020

The transcriptional coregulator OCA-B promotes expression of T cell target genes in cases of repeated antigen exposure, a necessary feature of autoimmunity. We hypothesized that T cell–specific OCA-B deletion and pharmacologic OCA-B inhibition would protect mice from autoimmune diabetes. We developed an Ocab conditional allele and backcrossed it onto a diabetes-prone NOD/ShiLtJ strain background. T cell–specific OCA-B loss protected mice from spontaneous disease. Protection was associated with large reductions in islet CD8+ T cell receptor specificities associated with diabetes pathogenesis. CD4+ clones associated with diabetes were present but associated with anergic phenotypes. The protective effect of OCA-B loss was recapitulated using autoantigen-specific NY8.3 mice but diminished in monoclonal models specific to artificial or neoantigens. Rationally designed membrane-penetrating OCA-B peptide inhibitors normalized glucose levels and reduced T cell infiltration and proinflammatory cytokine expression in newly diabetic NOD mice. Together, the results indicate that OCA-B is a potent autoimmune regulator and a promising target for pharmacologic inhibition.
Horizon hair from inversion symmetry
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Authors: Fernandes Karan , Ghosh Debodirna , Virmani Amitabh
Published: December 2020

The extreme Reissner–Nordström (ERN) solution has a discrete conformal isometry that maps the future event horizon to future null infinity and vice versa, the Couch–Torrence (CT) inversion isometry. We study the dynamics of a probe Maxwell field on the ERN solution in light of this symmetry. We present a gauge fixing that is compatible with the inversion symmetry. The gauge fixing allows us to relate the gauge parameter at the future horizon to future null infinity, which further allows us to study global charges for large gauge symmetries in the exterior of the ERN black hole. Along the way, we construct Newman–Penrose and Aretakis like conserved quantities along future null infinity and the future event horizon, respectively, and relate them via the CT inversion symmetry.
Mathematical and electronic model resistance/capacitor circuit of the action potential in an excitable cell
Authors: Vértiz-Hernández Juan Alberto , Vértiz-Hernández Angel Antonio , de Jesús Rangel-López Azahel , Campos-Cantón Isaac
Published: December 2020

Excitable cells are those that, when stimulated, generate an ion-dependent action potential; between them are neurons. The action potential has been a relevant target of study concerning cellular communication and behavior. This work aims to implement and validate the action potential of an excitable cell through resistance/capacitor (RC) circuits based on a mathematical/electrical model. This perspective can help researchers understand an excitable cell’s action potential from a mathematical and electrical approximation using a simple model. The experiment was designed based on RC circuits associated with the ionic channels of sodium (Na+) and potassium (K+). The proposed model also incorporates the ‘dendrite’ action not employed in the Hodgkin and Huxley model. Thus, a linear function by parts was used in mathematical modeling, recreating the excitable cell’s behavior through numerical and electronic simulation. The proposed mathematical/electrical model includes dendrites and capacitors not considered in previous models. In this scheme, the dendrite joined to the RC circuit describes the behavior as physiological, concerning the action potentials and the ions responsible.
Effects of conceptual and contextual task characteristics on students’ activation of mechanics conceptions
Authors: Just Anna M , von Aufschnaiter Claudia , Vorholzer Andreas
Published: December 2020

For promoting student learning in Newtonian mechanics, tailoring instruction to students’ conceptual needs is important. Although students’ conceptions can be inferred from research results, planning instruction is challenged by the fact that students may activate different conceptions for similar mechanics phenomena. For instance, changing the context or the wording of a task can evoke different conceptions. This article describes an approach to understanding how specific conceptual task characteristics (variations in the underlying concept or how the concept is approached) and contextual task characteristics (variations in the situation to which a concept applies) correlate with the activation of students’ conceptions in Newtonian mechanics. We employed a total of 72 single-choice tasks varying systematically conceptual and contextual task characteristics. Tasks were distributed over four test booklets and administered to a sample of undergraduates with physics as a major (N = 85) and minor subject (N = 114) as well as to high school students (age: ∼ 16, N = 157). Inferential statistical analysis was conducted to investigate if tasks with specific characteristics differed in their mean solution probabilities, revealing varying conceptions. Our findings suggest that even slight differences in how a task is situated (contextual characteristics), which law it addresses, and whether we ask for forces or for the state of motion (conceptual characteristics) result in significant differences regarding activated conceptions. For example, for Newton’s 1st law (with v = const. but ≠ 0) students activate more appropriate conceptions (higher solution probability) when tasks describe forces and ask for the resulting motion than vice versa. For planning instruction, it seems to be important to pay attention to the task characteristics used, to select them consciously, and to explicitly compare tasks that vary according to a particular characteristic.
An ultrafast response and precisely controllable soft electromagnet actuator based on Ecoflex rubber film filled with neodymium-iron-boron
Authors: Wang Xinli , Zhang Qian , Liu Ping , Zhu Xun , Wu Chen , Wang Jinyu , Liu Caixia , Wang Junfeng , Gao Yang , Song Aiguo , Huang Ying
Published: December 2020

Soft actuator is widely applied in soft grasp and artificial actuation. However, the characteristics of fast response and precise controllability are challenges for soft actuators. In this report, an ultrafast response and precisely controllable soft electromagnet actuator based on Ecoflex rubber film filled with neodymium-iron-boron is proposed. After optimizing the matrix and size of the actuator, the flexible magnetic actuator shows many merits including ultrafast response (<0.1 s), large elongation (<120%), excellent working stability, precision for long time working and customized designs. Based on customized patterns, different kinds of grippers have been made and they can realize the function of grasp and clutching of spherical and cylindrical objects. Furthermore, this actuator can be used on designed devices to build a pump system which can implement liquid injection and liquid blend. The proposed soft actuator has a great prospect in the practical application such as medical devices and soft robotics.
Intrinsic ferromagnetic semiconductors in rhombohedral RMnO3 (R = Sc, Y, and Lu) with high critical temperature and large ferroelectric polarization
Authors: Zhang Chengfeng , Li Zixu , Li Guannan , Gao Benling , Liang Feng , Li Zhongwen , Song Guang
Published: December 2020

Ferromagnetic (FM) semiconductors have been recognized as the cornerstone for next-generation highly functional spintronic devices. However, the development in practical applications of FM semiconductors is limited by their low Curie temperatures (T
C). Here, on the basis of model analysis, we find that the FM super-exchange couplings in the d
5 − d
3 system can be significantly strengthened by reducing the virtual exchange gap (G
ex) between occupied and empty e

g
orbitals. By first-principle calculations, we predict robust ferromagnetism in three rhombohedral RMnO3 (R = Sc, Y, and Lu) compounds with the T
C that is as high as ∼1510 K (YMnO3). The oxygen breathing motions open a band gap and create an unusual Mn2+/Mn4+ charge ordering of the Mn-d electrons, which play an important role in altering the G
ex. Interestingly, the rhombohedral RMnO3 compounds are also ferroelectric (FE) with a large spontaneous polarization approaching that of LiNbO3. These results not only deepen the understandings of magnetic couplings in d
5 − d
3 system, but also provide a way to design room-temperature FM–FE multiferroics.
GLONASS precise orbit determination based on L-band and SLR data
Authors: Yang Honglei , Xu Tianhe , Nie Wenfeng , Fang Zhenlong , Li Min , Guan Meiqian
Published: December 2020

Precise orbit determination (POD) plays an important and fundamental role in Global Navigation Satellite System (GNSS) applications. The Russian GLONASS is a mature full-constellation GNSS system that provides both L-band and satellite laser ranging (SLR) data. To explore the current individual GLONASS POD capability, we conduct the multi-day solution of the GLONASS L-band, SLR-only, and the combined L-band/SLR POD from 1 to 30 September, 2019. Seven strategies are investigated to explore the impact of the multi-day solution strategy on the GLONASS SLR-only POD. For the L-band POD, we find that the 3 d solution is always optimal without the influence of the eclipse. The overall average root mean square (rms) values are 3.7, 4.1 and 4.7 cm in the radial-tangential-normal (RTN) directions by comparison with the Center for Orbit Determination in Europe (CODE) orbits. The corresponding RTN rms values are 1.2, 4.3 and 3.4 cm for the orbital overlaps. For the SLR-only POD, the 9 d solution is the best with the orbital overlap RTN rms values of 0.7, 4 and 5.7 cm. Meanwhile, the RTN rms values are 1.6, 8 and 14 cm for the CODE orbits, which is obviously better than those of the L-band orbits in the R-direction. Due to the inaccuracy of the estimated dynamic parameters, the orbital consistency degrades with the increase of the multi-day solution arcs. Last but not least, a slight improvement in accuracy can be achieved in the combined L-band/SLR POD, especially in the R-direction of the 1 d solution. As a typical case, the external consistency is improved by 0.4–1.2, −0.3–1.7 and 0.1–1.5 cm in the RTN directions for the 3 d solution of the GLONASS R14 during the day of the year 256–265, 2019.
Development of robustness evaluation strategies for enabling statistically consistent reporting
Authors: Sterpin E , Rivas Sara T , Van den Heuvel F , George B , Lee J A , Souris K
Published: December 2020

Robustness evaluation of proton therapy treatment plans is essential for ensuring safe treatment delivery. However, available evaluation procedures feature a limited exploration of the actual robustness of the plan and generally do not provide confidence levels. This study compared established and more sophisticated robustness evaluation procedures, with quantified confidence levels. We have evaluated several robustness evaluation methods for 5 bilateral head-and-neck patients optimized considering spot scanning delivery and with a conventional CTV-to-PTV margin of 4 mm. Method (1) good practice scenario selection (GPSS) (e.g. +/− 4 mm setup error 3% range uncertainty); (2) statistically sound scenario selection (SSSS) either only on or both on and inside isoprobability hypersurface encompassing 90% of the possible errors; (3) statistically sound dosimetric selection (SSDS). In the last method, the 90% best plans were selected according to either target coverage quantified by D
95 (SSDS_D
95) or to an approximation of the final objective function (OF) used during treatment optimization (SSDS_OF). For all methods, we have considered systematic setup and systematic range errors. A mix of systematic and random setup errors were also simulated for SSDS, but keeping the same conventional margin of 4 mm. All robustness evaluations have been performed using the fast Monte Carlo dose engine MCsquare. Both SSSS strategies yielded on average very similar results. SSSS and GPSS yield comparable values for target coverage (within 0.5 Gy). The most noticeable differences were found for the CTV between GPSS, on the one hand, and SSDS_D
95 and SSDS_OF, on the other hand (average worst-case D
98 were 2.8 and 2.0 Gy larger than for GPSS, respectively). Simulating explicitly random errors in SSDS improved almost all DVH metrics. We have observed that the width of DVH-bands and the confidence levels depend on the method chosen to sample the scenarios. Statistically sound estimation of the robustness of the plan in the dosimetric space may provide an improved insight on the actual robustness of the plan for a given confidence level.
A semi-empirical model for scatter field reduction in digital mammography
Authors: Marimón E , Marsden P A , Nait-Charif H , Díaz O
Published: December 2020

X-ray mammography is the gold standard technique in breast cancer screening programmes. One of the main challenges that mammography is still facing is scattered radiation, which degrades the quality of the image and complicates the diagnosis process. Anti-scatter grids, the main standard physical scattering reduction technique, have some unresolved challenges as they increase the dose delivered to the patient, do not remove all the scattered radiation and increase the cost of the equipment. Alternative scattering reduction methods based on post-processing algorithms, have lately been under investigation. This study is concerned with the use of image post-processing to reduce the scatter contribution in the image, by convolving the primary plus scatter image with kernels obtained from simplified Monte Carlo (MC) simulations. The proposed semi-empirical approach uses up to five thickness-dependant symmetric kernels to accurately estimate the scatter contribution of different areas of the image. Single breast thickness-dependant kernels can over-estimate the scatter signal up to 60%, while kernels adapting to local variations have to be modified for each specific case adding high computational costs. The proposed method reduces the uncertainty to a 4%–10% range for a 35–70 mm breast thickness range, making it a very efficient, case-independent scatter modelling technique. To test the robustness of the method, the scattered corrected image has been successfully compared against full MC simulations for a range of breast thicknesses. In addition, clinical images of the 010A CIRS phantom were acquired with a mammography system with and without the presence of the anti-scatter grid. The grid-less images were post-processed and their quality was compared against the grid images, by evaluating the contrast-to-noise ratio and variance ratio using several test objects, which simulate calcifications and tumour masses. The results obtained show that the method reduces the scatter to similar levels than the anti-scatter grids.
OCT4 expression in human embryonic stem cells: spatio-temporal dynamics and fate transitions
Authors: Wadkin L E , Orozco-Fuentes S , Neganova I , Lako M , Barrio R A , Baggaley A W , Parker N G , Shukurov A
Published: December 2020

The improved in vitro regulation of human embryonic stem cell (hESC) pluripotency and differentiation trajectories is required for their promising clinical applications. The temporal and spatial quantification of the molecular interactions controlling pluripotency is also necessary for the development of successful mathematical and computational models. Here we use time-lapse experimental data of OCT4-mCherry fluorescence intensity to quantify the temporal and spatial dynamics of the pluripotency transcription factor OCT4 in a growing hESC colony in the presence and absence of BMP4. We characterise the internal self-regulation of OCT4 using the Hurst exponent and autocorrelation analysis, quantify the intra-cellular fluctuations and consider the diffusive nature of OCT4 evolution for individual cells and pairs of their descendants. We find that OCT4 abundance in the daughter cells fluctuates sub-diffusively, showing anti-persistent self-regulation. We obtain the stationary probability distributions governing hESC transitions amongst the different cell states and establish the times at which pro-fate cells (which later give rise to pluripotent or differentiated cells) cluster in the colony. By quantifying the similarities between the OCT4 expression amongst neighbouring cells, we show that hESCs express similar OCT4 to cells within their local neighbourhood within the first two days of the experiment and before BMP4 treatment. Our framework allows us to quantify the relevant properties of proliferating hESC colonies and the procedure is widely applicable to other transcription factors and cell populations.
AGN Jets and a Fanciful Trio of Black Holes in the Abell 85 Brightest Cluster Galaxy
Authors: Madrid Juan P.
Published: December 2020

A new radio map of the Abell 85 Brightest Cluster Galaxy (BCG) was obtained with the Karl G. Jansky Very Large Array. With a resolution of 0.″02, this radio image shows two kiloparsec-scale bipolar active galactic nucleus jets emanating from the active galactic nucleus of the A85 BCG. The galaxy core appears as a single entity on the new radio map. It has been assumed that the A85 BCG contained a binary black hole in its core. However, Chandra X-ray data and the new high-resolution radio map show no evidence that the A85 BCG harbors a binary black hole. The assumption that this galaxy contains a binary black hole was based on the analysis of its optical surface brightness profile obtained under poor seeing conditions. We demonstrate how the well-known blurring effects of atmospheric seeing can mimic the effects of a binary supermassive black hole (SMBH). Likewise, SDSS J004150.75–091824.3 was postulated to be “a third” SMBH associated with the BCG. In the optical and X-rays, SDSS J004150.75–091824.3 is a point-like source located ∼14″ away from the nucleus of the A85 BCG. A new spectrum of SDSS J004150.75–091824.3, obtained with the 10.4 m Gran Telescopio Canarias, reveals that this source is a background quasar at a redshift of z = 1.5603 ± 0.003 and not associated in any way with the A85 cluster.
Online asynchronous detection of error-related potentials in participants with a spinal cord injury using a generic classifier
Authors: Lopes-Dias Catarina , Sburlea Andreea I , Breitegger Katharina , Wyss Daniela , Drescher Harald , Wildburger Renate , Müller-Putz Gernot R
Published: December 2020

For brain–computer interface (BCI) users, the awareness of an error is associated with a cortical signature known as an error-related potential (ErrP). The incorporation of ErrP detection into BCIs can improve their performance. Objective. This work has three main aims. First, we investigate whether an ErrP classifier is transferable from able-bodied participants to participants with a spinal cord injury (SCI). Second, we test this generic ErrP classifier with SCI and control participants, in an online experiment without offline calibration. Third, we investigate the morphology of ErrPs in both groups of participants. Approach. We used previously recorded electroencephalographic data from able-bodied participants to train an ErrP classifier. We tested the classifier asynchronously, in an online experiment with 16 new participants: 8 participants with SCI and 8 able-bodied control participants. The experiment had no offline calibration and participants received feedback regarding the ErrP detections from the start. To increase the fluidity of the experiment, feedback regarding false positive ErrP detections was not presented to the participants, but these detections were taken into account in the evaluation of the classifier. The generic classifier was not trained with the user’s brain signals. However, its performance was optimized during the online experiment by the use of personalized decision thresholds. The classifier’s performance was evaluated using trial-based metrics, which considered the asynchronous detection of ErrPs during the entire trial’s duration. Main results. Participants with SCI presented a non-homogenous ErrP morphology, and four of them did not present clear ErrP signals. The generic classifier performed better than chance in participants with clear ErrP signals, independently of the SCI (11 out of 16 participants). Three out of the five participants that obtained chance level results with the generic classifier would have not benefitted from the use of a personalized classifier. Significance. This work shows the feasibility of transferring an ErrP classifier from able-bodied participants to participants with SCI, for asynchronous detection of ErrPs in an online experiment without offline calibration, which provided immediate feedback to the users.
Role of dynamics of the population inversion in attosecond pulse amplification in the active medium of a plasma-based X-ray laser dressed by an optical laser field
Authors: Antonov V. A. , Khairulin I. R. , Ryabikin M. Yu.
Published: December 2020

We study the role of dynamics of the population inversion of an active medium of an X-ray laser dressed by a strong infrared (IR) laser field in the amplification of an attosecond pulse train produced via high-harmonic (HH) generation by the same IR field. We derive an analytical solution for the case of a recombination hydrogen-like X-ray laser, which shows that the time dependence of the population inversion strongly affects the level of the HH amplification and the envelope of the amplified attosecond pulse train. The possibilities for experimental implementation are discussed for the case of C5+ X-ray laser with the transition wavelength ∼ 3.4 nm in the “water window” range.
Superluminal phase velocity approach for suppression of Numerical Cherenkov Instability in Maxwell solver
Authors: Samsonov A , Pukhov A , Kostyukov I
Published: December 2020

A modification of a standard finite-difference time-domain (FDTD) Maxwell solver is proposed based on the inclusion of the terms of the higher order in the finite differences approximation. By selecting the coefficients of this hybrid scheme the numeric dispersion of the electromagnetic waves can be fine-tuned. It is shown that a particular choice of the coefficients leads to the phase velocity of all the waves being slightly larger than speed of light. Results of the 3D Particles-In-Cells (PIC) simulations demonstrate that the proposed scheme of the Maxwell solver is efficient to mitigate the Numerical Cherenkov Instability (NCI) when simulating ultrarelativistic charged beams.
Clock transition excitation efficiency determination using an additional short clock π-pulse
Authors: Provorchenko D , Mishin D , Fedorova E , Tregubov D , Golovizin A , Sorokin V , Khabarova K , Kolachevsky N
Published: December 2020

We demonstrate a simple and efficient readout procedure of the 1.14^m clock transition excitation efficiency in neutral thulium atoms. Our method utilizes additional but short clock n-pulse to measure number of atoms excited by spectroscopic clock pulse, that allows to determine excitation probability insensitive to fluctuation of number of atoms in the trap. It is important that this method can be used for both hyperfine components of the clock transition and does not require any additional lasers in the setup.
Resonant signal transmission in optical structures with periodical profile of permittivity
Authors: Bogatskaya A V , Nikiforova P M , Popov A M
Published: December 2020

We consider a general physical approach to enhance the efficiency of terahertz bolometric detectors. The approach is based on the concept of resonant tunneling of an electromagnetic wave which is similar to quantum particle tunneling in quantum mechanics. Placing resonator under nontransparent conductive layer (plasma, metal or superconductor) helps to increase under certain conditions the field intensity both beyond the nontransparent layer and within it, thus enhancing the detection efficiency. If the frequency of the incident radiation matches with one of the eigenfrequencies of a resonator the effect of resonant tunneling through the conducting layer can be observed. Replacing single resonator with a resonator sequence separated with conductive layers result in formation of an absorption band instead of one resonant frequency. The calculations have shown that absorption of up to 60% of the energy of the THz pulses can be easily achieved in the considered structures even at the detection of broadband radiation.
Numerical simulations of the polarization-sensitive response in nanospikes array
Authors: Busleev N. I. , Kudryashov S. I. , Saraeva I. N. , Danilov P. A. , Rudenko A. A. , Zayarny D. A. , Ionin A. A. , Minh P. H.
Published: December 2020

In experimental backscattering spectra of a gold film were found resonances which may reveal features of the film inner structure. The explanation of these features based on the analysis of the structure’s unit cell and its response to laser radiation was proposed.
Ultrafast electron dynamics and energy deposition during IR-visible femtosecond laser ablation of fluorite
Authors: Danilov P A , Galkin M L , Kovalev M S , Rupasov A E , Smayev M P , Zolot’ko A S , Ionin A A , Kudryashov S I , Zakoldaev R A
Published: December 2020

The action of ultrashort laser pulses on dielectrics leads to the processes of redistribution of the laser pulse energy in the interaction region. The mechanisms of ultrafast energy deposition and the electron dynamics under the action of ultrashort laser pulses determine the type of final structures or elements in the transparent dielectrics. One type of these elements is a birefringent nanogratings formed with an orientation perpendicular to the laser radiation. In this work, laser-induced birefringent structures in calcium fluoride (CaF2) bulk were obtained under the action of tightly-focused laser pulses with durations 0.3-3.8 ps and wavelengths of 515 and 1030 nm. Birefringence in modified region was analyzed using polarization contrast optical microscope with Abrio imaging system.
Comparative study of low-order harmonic generation in gas and cluster media at Ti:Sa femtosecond laser intensity up to 2000 TW/cm2
Authors: Zhvaniya I A , Dzhidzhoev M S , Semenov T A , Savel’ev A B , Stremoukhov S Y , Usmanov T , Gordienko V M
Published: December 2020

In comparative experiments, it was found that the maximum efficiency of third harmonic generation (THG) in cluster nanoplasma was ∼9x10−5 and was approximately 4 times less effective than the case of THG in gas under similar experimental conditions. This result is consistent with theoretical calculations and show that THG amplitude in a gas is about an order of magnitude higher than in a cluster medium. The discrepancy between the THG efficiency in gas and clusters obtained theoretically and experimentally in discussed.
Numerical modeling of pulse-pumped ultrafast regenerative amplifier with unstable pump laser
Authors: Kostryukov P V , Cheshev E A
Published: December 2020

A numerical model of a regenerative amplifier based on the Frantz-Nodvik equation with spatially dependent stored energy density in the active medium has been developed. The model was used to investigate the stability of the output energy of the amplifier associated with fluctuations of the pump energy and pump beam position. It was found that, same as in the known case with the fluctuations of the pump energy, the influence of the fluctuations of the pump beam position is much weaker at oversaturated operation of the regenerative amplifier. Opposite to fluctuations of the pump energy, fluctuations of the pump beam position result in highly-asymmetric histogram of the output energy, which is highly skewed to the lower energies.
A novel quad-channel 10 Gbps CMOS VCSEL array driver with integrated charge pumps
Authors: Huang X. , Gong D. , Guo D. , Hou S. , Huang G. , Kulis S. , Liu C. , Liu T. , Moreira P. , Rodríguez A. Sánchez , Sun H. , Sun Q. , Troska J. , Xiao L. , Zhang L. , Zhang W. , Ye J.
Published: December 2020

We present a novel design and the test results of a 4-channel driver for an array of Vertical-Cavity Surface-Emitting Lasers (VCSELs). This ASIC, named cpVLAD and fabricated in a 65 nm CMOS technology, has on-chip charge pumps and is for data rates up to 10 Gbps per channel. The charge pumps are implemented to address the issue of voltage margin of the VCSEL driving stage in the applications under low temperature and harsh radiation environment. Test results indicate that cpVLAD is capable of driving VCSELs with forward voltages of up to 2.8 V using 1.2 V and 2.5 V power supplies with a power consumption of 94 mW/channel.
Painlevé type reductions for the non-Abelian Volterra lattices
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Authors: Adler V E
Published: December 2020

The Volterra lattice admits two non-Abelian analogs that preserve the integrability property. For each of them, the stationary equation for non-autonomous symmetries defines a constraint that is consistent with the lattice and leads to Painlevé-type equations. In the case of symmetries of low order, including the scaling and master-symmetry, this constraint can be reduced to second order equations. This gives rise to two non-Abelian generalizations for the discrete Painlevé equations and and for the continuous Painlevé equations P3, and P5.
Characteristics of visiting urban open spaces in Sana’a city in Yemen
Authors: Alwah A A Q , Li W , Al-Attar A N M
Published: December 2020

Knowledge of the characteristics of visiting and using urban open spaces is the key to the effective design, development, and management of these spaces. Although research has conducted many studies related to the use and importance of urban environments in Europe, America, Australia, China, and some East Asian countries, there is a lack in such studies in the Middle East, especially in Yemen. This study covers a part of the knowledge gap by verifying the characteristics of visiting and using three selected open spaces in Sana’a city in Yemen through self-reporting of the users of these spaces. The study shows that Yemenis go to open spaces for recreation, family seating, playing with children, and walking. Furthermore, users prefer spaces that provide appropriate and adequate seating areas, various and modern entertainment facilities, a high level of hygiene and maintenance, and safe spaces that are free from intruders. This knowledge benefits the urban designers and developers in Yemen to rehabilitate degraded open areas and design new public spaces.
Simulation study on performance of plate heat exchanger for heat pump
Authors: Yuqing Zhao , Jianfeng Shao , Yun Dai , xin Yang , jiayu Deng
Published: December 2020

For the plate heat exchanger of heat pump system, the convection heat transfer correlation of condenser and evaporator was used to simulate the heat transfer of heat exchanger, and the experimental test of heat exchanger was carried out in the heat pump system. The numerical simulation results were compared with the experimental results. The results show that the average error between the numerical simulation results of condenser and evaporator and the experimental results are 5.75% and 1.13% respectively, which proves that the simplified hypothesis, the heat transfer model and the solution method used in the numerical simulation are reasonable for the evaporation and condensation process of plate heat exchanger for heat pump.
Research on Planning and Design of Resident-Friendly Community Parks: Taking the Huapu Park of Jinan City as an Example
Authors: Deyi Kong , Cheng Li
Published: December 2020

The outbreak of the novel coronavirus pandemic in early 2020 has raised people’s concern about living and ecological problems in densely populated cities. Community parks turn into the most accessible ecological green spaces shared by the public. Through questionnaires, this paper surveys the functional zones, cultivation of vegetation and public utilities of the Huapu Park which is situated in Jingshi Road, Jinan City. The purpose is to explore the improvement of landscape planning when community parks play a role in emergency and disaster prevention, and interactive participation, so as to provide constructive suggestions for the building of resident-friendly community parks.
Research on the Optimal Spacing of Urban Environmental Sanitation Facilities: Smoke-extinguishing Pillar as an Example
Authors: Li Yong , Zhou Cheng , Lu Haixiang , Xu Han , Li Gang
Published: December 2020

Since the spacing of urban environmental sanitation facilities is not reasonable enough, customers and service desks in the queuing theory were used to simulate the environmental sanitation facilities and pedestrians in daily life, and the established queuing system was then optimized based on the purpose of minimum costs. This optimization model was used to determine the optimal spacing of the sanitation facilities for street-like linear sites, and quantify the positive and negative utility of whether garbage is thrown into the sanitation facilities. Moreover, the optimal spacing of the sanitation facilities on street-like linear places was calculated according to the coefficient “k” and the maximum tolerable distance “s” of pedestrians holding a piece of garbage. Moreover, an algorithm for park-like flat sites was provided by establishing a set covering model. Then the maximum tolerable distance of pedestrians holding a piece of garbage was obtained through field research, which was then used in practical calculation. Finally, conclusions and suggestions were given correspondingly.
Analysis of the Causes and Solutions of Apartheid Based on Schelling Model with Welfare Policy
Authors: Pan Jiateng , Yoshikawa Atsushi , Yamamura Masayuki
Published: December 2020

In recent years, with the widespread dissemination of the concept of anti-racial discrimination, various countries have introduced a series of welfare policies for ethnic minorities, trying to control population apartheid to alleviate the generation of racial conflicts, and many achievements have been made. However, apartheid seems to have rebounded recently. This paper proposes the Schelling model with welfare policies to analyze the reasons for the rebound phenomenon and propose possible solutions.
Analysis of The MICE Tourism Research in China in the Last Twenty Years
Authors: Xu Jin , Ruhanen Lisa , Solnet David J.
Published: December 2020

The Meetings, Incentives, Conferences and Exhibitions (MICE) tourism has developed rapidly in China and has become an important tourism product. By use of CiteSpace software, authors performed the scientific measurement and visual analysis of MICE tourism research papers collected in China National Knowledge Infrastructure (CNKI), including the research institutions, important journals, core authors and other external characteristics, and the knowledge graphs of co-occurrence, clustering, burst and time-line of keywords. The results showed that MICE tourism research in China has achieved great progress in the last 20 years. However, these researches generally lack of long-term investigation and cooperation, and the technology and forward-looking are not strong enough. The future research needs to be improved in depth, precision and technology, and sustainable MICE tourism should be regarded as an important concept and goal. The paper provides a new perspective for the scientific observation and analysis of MICE tourism research and development in China.
Evaluation of the EDPs’ Cultural Assimilation Based on Epidemic Model
Authors: Chen Shubai , Sun Shuo
Published: December 2020

In recent UN resolutions, EDPs are defined as refugees. Based on the systematic effects caused by EDPs, we propose an optimization model to predict the number of EDPs and protect the traditional culture of EDPs. Based on the basis of our proposed model, we can demonstrate the importance of the policy proposed based on our model.

Firstly, we use climate phenomena such as sea-level rise and soil desertification to determine the countries at risk. Kiribati and Mongolia are studied in our model. We propose to use the power-law distribution to calculate the number of EDPs in the countries at risk. Through the qualitative analysis, it shows that “national collective migration to countries with similar cultural backgrounds” can effectively reduce the risk of cultural loss.

Secondly, in terms of cultural protection, we use SIS and SEIR infectious disease models to simulate the process of cultural assimilation and budget the time needed for cultural assimilation of EDPs. We also revised the policy according to the index of refugee and the speed of cultural assimilation. (1) international organizations should give appropriate economic assistance to the recipient countries. (2) the recipient country should take strong cultural protection measures when EDPs start to migrate. (3) the recipient country should try its best to provide jobs to EDP without harming the interests of its own people.

Finally, we proposed an optimization model to verify that when the policy is implemented, the cultural protection has been greatly improved. By comparing with the natural state of the policy not adopted, the importance of the optimization model of human rights and cultural protection based on EDPs proposed by us is illustrated.
Study on landscape rheology of architectural cultural heritage in Shandong section of Beijing Hangzhou Grand Canal
Authors: Sui Yanhui , Zhang Jian
Published: December 2020

Architectural heritage is an important part of the cultural heritage of Beijing Hangzhou Grand Canal and an important carrier of historical culture. On the basis of expounding the temporal dynamic pattern of architectural cultural heritage of Beijing Hangzhou Grand Canal, this paper reveals its leading process and main factors. The results show that the time dynamic pattern mainly depends on political, cultural, institutional and economic factors. At the same time, this paper puts forward some innovative strategies for its protection and sustainable development.
CBR-based dynamic decision-making method for emergencies
Authors: Wang Cui , Song Yinghua , Fang Danhui
Published: December 2020

The randomness of emergencies is very important to emergency management, and case-based reasoning has attracted the attention of emergency decision-makers. In order to improve the one-sidedness of the existing emergency decision-making method based on static case-based reasoning, this paper fully considers the development and evolution stage of the event, and proposes a CBR-based dynamic emergency decision-making method. First, the emergency event is decomposed into multiple time stages; then the comprehensive attributes of each stage are determined according to the event description and treatment measures to calculate the attribute similarity; then the case similarity is calculated through the attribute similarity, and the decision-making plan of current event stage is formed by combining the treatment measures of the case with the highest similarity; at the same time, the current decision-making measures are involved in the case reasoning of the next stage. Finally, a high-rise building fire case in the city shows the feasibility of this method.
Applying beacon sensor alarm system for construction worker safety in workplace
Authors: Huang Ying , Fansheng Kong , Yifei He
Published: December 2020

The construction site is one of the most dangerous workplaces among all the industries, workers are exposed to various hazards sources. Ubiquitous accidents occur even with detailed regulations and laws. Situation awareness theory revealed that there are three processes when people are dealing with the changing environment: perception of environmental situation, comprehension of what people are dealing with and decision-making. The likelihood of risky behaviours increases a lot when any of these processes go wrong. In this paper, the author proposed an alarm system to help workers get a better perception of construction site and improve the efficiency and quality of safety management. In this system, a beacon sensor will be deployed on the hazard source and it will keep send Bluetooth package to receiver equipment. Workers will carry the receiver, a BLE sensor, to calculate the distance between people and the hazard point. If the distance is less than the setting number, the sensor will trigger the alarm to broadcast siren and send the unsafety behaviour event to manager backend to archive the entire process.
Assessing temporal and spatial patterns of surface-water quality with a multivariate approach: a case study in Uruguay
Authors: Gorgoglione A , Alonso J , Chreties C , Fossati M
Published: December 2020

The ecological state of inland waters of the Santa Lucía watershed, the primary drinking water source of Uruguay, has raised interest since it presents the seasonal phenomenon of eutrophication. For this reason, an in-depth understanding of the behaviour in time and space of the water-quality variables that characterize this stream is essential. Therefore, this study aims to evaluate the occurrence of spatial and temporal patterns of water-quality variables (Q, turbidity, T, TN, NO3
-, NO2
-, NH4
+, TP, DO, BOD5) in the Santa Lucía Chico watershed with the aid of multivariate statistical tools. The principal component analysis, coupled with k-means cluster analysis, helped to identify a seasonal variation (fall-winter and spring-summer). The hierarchical cluster analysis allowed us to classify the water-quality monitoring stations in three groups in the fall-winter season. The loadings values of the cluster analysis highlighted the most significant pollutants at each monitoring station. The outcomes of this work are expected to contribute valuable knowledge for determining effective management strategies to reduce stream pollution and protect the aquatic ecosystem health of the study area.
Effect of particle size on the physicochemical property of the peel powder from Aloe barbadensis
Authors: Ma L K , Chen K , Tian X F , Gao Y H , Zhang S A , Zhu L X
Published: December 2020

Aloe barbadensis (Aloe vera) has long been used in food, cosmetic and pharmaceutical industries. In order to maximally extract soluble sugars, different drying methods, such as heat-drying (HD), air-drying (AD), vacuum freeze drying (VFD), and microwave drying (MD), on the sugar content were investigated in the present work. Besides, the relationship between the particle size and the physicochemical property of the peel powder obtained by ultramicro-pulverization was also explored. The results showed that different drying method did have significant effect on the soluble sugar content. HD, AD, and VFD possessed similar sugar content (approximately 8.27, 8.46, and 8.46 g/100g, respectively). The highest sugar content was found in MD (9.36 ± 0.30 g/100g), indicating that MD was the most effective way to extract sugars from Aloe vera peel among these four methods. The particle size of the peel power after dried by MD was affected by the crusher time and power. The higher the power, and the longer crusher time, the smaller particle size of the powder. Along with the decreasing of particle size, the color parameter (B value) of the peel powder significantly decreased from 24.47 to 16.90 (P < 0.05). The water holding capacity also decreased when the D (0.5) reduced due to the lower binding capacity of small size particle towards water. As the reduction of D (0.5) value, the water holding capacity decreased (from 6.21% to 3.52%). The present work could provide valuable information for the comprehensive utilization of the by-products of Aloe vera.
Influence of trophic status on zooplankton structure in Chelyabinsk region lakes (Russia)
Authors: Mashkova Irina , Kostryukova Anastasiya , Shchelkanova Elena , Trofimenko Viktor
Published: December 2020

Eutrophication of water-bodies, as well as lakes, is currently one of the crucial problems of both theoretical and applied ecology. Zooplankton is sensitive to changes in the ecological state of different types of reservoirs. The article analyses differences and similarities of zooplankton communities in 10 lakes of Kisegach - Miassovo hydrological system of Chelyabinsk region (Russia). The current research aims at identifying taxonomic structure of zooplankton communities of the lakes in Chelyabinsk region (Russia) and stating the influence of some abiotic factors on its formation. Integrated samples were gathered in summer 2015 - 2019. The given paper studied the correlation of the main taxonomic groups of zooplankton, marked a regular decrease in the number of zooplankton species under adverse environment. When the trophic level of water in natural fresh lakes changes in the direction of oligotrophic-mesotrophic-eutrophic, the total number of zooplankton decreases from 400.90 individuals per L−1 to 106.06 individuals per L−1. In the same direction, the number of Cladocera representatives decreases (from 362.03 individuals per L−1 to 66.34 individuals per L−1) and the number of Copepoda representatives decreases (from 34.01 individuals per L 12.67 individuals per L−1), and the number of Rotifera representatives increases (from 6.97 individuals per L−1 to 26.60 individuals per L−1).