Miracle-dz/UniFAR-FTUs huggingface dataset:
Influence of various drying methods on physicochemical characteristics, antioxidant activity, and bioactive compounds in Centella asiatica L. leaves: a comparative study

This comparative study aimed to evaluate the effects of different drying methods such as solar drying, shade drying (SHD), freeze drying (FD), oven drying, and microwave drying on the physicochemical properties, bioactive components, and antioxidant activity of Centella asiatica. The results showed that out of all the treated samples, FD-treated samples showed the lowest moisture content (2.4%), the lowest water activity (0.24%), and the highest rehydration ratio (5.51%). For samples treated using different drying methods, significant differences in Commission on Illumination – LAB (L *, a *, and b *) values and total color difference (E ) were observed. FD-treated samples showed the minimum color change (E ) and highest lightness (L *). Additionally, upon Fourier-transform infrared spectral analysis, no major changes in the functional groups were observed between C. asiatica leaves processed using different drying methods. FD-treated samples showed the highest antioxidant activity followed by SHD-treated samples, as measured by 2,2-diphenyl-1-picrylhydrazyl and 2,2-azino-bis-3-ethylbenzo-thiazoline-6-sulphonic acid radical scavenging assays. The phenolic (chlorogenic acid, rutin, kaempferol, and quercetin) and triterpene saponin (madecassoside, asiaticoside, madecassic acid, and asiatic acid) contents of the dried samples of C. asiatica were measured using high-performance liquid chromatography, which showed that the FD method allowed for the highest retention of phenolic and triterpene saponins among the tested drying techniques. The physicochemical characteristics, antioxidant potential, and bioactive retention of the samples that underwent FD treatment were superior to those of other methods, and therefore, FD can be employed as the first-line drying technique for processing C. asiatica leaves.
Constraining the parameters of the pulsar wind nebula DA 495 and its pulsar with Chandra and XMM–Newton

We present spectral and timing analyses of the X-ray emission from the pulsar wind nebula DA 495 and its central object, J1952.2+2925, suggested to be the pulsar, using archival Chandra and XMM-Newton data. J1952.2+2925 has a pure thermal spectrum which is equally well fitted either by the blackbody model with a temperature of $\approx 215$ eV and an emitting area radius of $\approx 0.6$ km or by magnetized neutron star atmosphere models with temperatures of 80-90 eV. In the latter case the thermal emission can come from the entire neutron star surface which temperature is consistent with standard neutron star cooling scenarios. We place also an upper limit on the J1952.2+2925 nonthermal flux. The derived spectral parameters are generally compatible with published ones based only on the Chandra data, but they are much more accurate due to the inclusion of XMM-Newton data. No pulsations were found and we placed an upper limit for the J1952.2+2925 pulsed emission fraction of 40 per cent. Utilizing the interstellar absorption-distance relation, we estimated the distance to DA 495, which can be as large as 5 kpc if J1952.2+2925 emission is described by the atmosphere models. We compiled possible multi-wavelength spectra of the nebula including radio data; they depend on the spectral model of the central object. Comparing the results with other pulsar plus wind nebula systems we set reasonable constraints on the J1952.2+2925 spin-down luminosity and age. We suggest that the Fermi source 3FGL J1951.6+2926 is the likely $\gamma$-ray counterpart of J1952.2+2925.
Ice/Snow Surface Temperature Retrieval From Chinese FY-3D MERSI-II Data: Algorithm and Preliminary Validation

Ice/snow surface temperature (I/SST) is an essential parameter in many research fields such as the climate change, energy, and matter balance of the South pole regions. Recently, many algorithms have been developed for various satellite observations to derive the I/SST. However, rare studies focus on accurate I/SST retrieval from the observations of Chinese MEdium Resolution Spectral Imager II (MERSI-II) instrument onboard the FY-3D satellite with the spatial resolution of 250 m and temporal resolution of about five days, which just bridges the specifications of the Aqua-MODerate-resolution Imaging Spectroradiometer (MODIS) (1000-m pixel size and 0.5-day revisit cycle) and Landsat-Thermal InfraRed Sensor (TIRS) (100-m pixel size and 16-day revisit cycle) instruments. In this study, a new method with correction of striping noise and consideration of angular emissivity effect is developed for the MERSI-II data to accurately retrieve the I/SST. The performance of the proposed method is assessed by using both MODIS product and ground I/SST measurements. The results show that the FY-3D I/SST retrieval accuracy is comparable to the MODIS product, with a discrepancy of < 1.6 K. Ground-based validation reveals that the proposed method could be used to accurately retrieve the I/SST with a root-mean-square error (RMSE) of < 1.5 K. Overall, this study proposes a method for accurate I/SST retrieval from the FY-3D MERSI-II data with the pixel size of 250 m, implying the possibilities in improving the spatio-temporal resolutions of the current I/SST products. Moreover, the proposed method is also helpful to improve our understandings of the polar regions.
Design of a Hybrid Frequency Selective Rasorber With Wideband Reflection Suppression

A hybrid frequency selective rasorber is presented in this letter based on hybrid lossy layers. The hybrid lossy layers is composed of an absorption-transmission (A-T) layer and a transmission-absorption (T-A) layer, which are responsible for the absorption performance in the low and high frequency respectively. The A-T layer is composed of a lumped-resistors loaded cross-frame structure (CFS), which connects four parallel inductor and capacitor resonators. The T-A layer is constructed by a parallel plate capacitor loaded square loop resonator connecting four lumped-resistor loaded T-shaped metal branches. The frequency selective surface layer is composed of metal square slot. The hybrid frequency selective rasorber provides a transmission window around 10 GHz and two-sided absorption bands in 3.19—9 GHz and 11.85–21.18 GHz, meanwhile the wideband reflection suppression (S11<−10 dB) is achieved from 3.2 to 21.18 GHz (147%). An assembled prototype is measured to verify the simulated results.
Absorption signatures of warm-hot gas at low redshift: O vi

We investigate the origin and physical properties of O vi absorbers at low redshift (z= 0.25) using a subset of cosmological, hydrodynamical simulations from the OverWhelmingly Large Simulations (OWLS) project. Intervening O vi absorbers are believed to trace shock-heated gas in the warm-hot intergalactic medium (WHIM) and may thus play a key role in the search for the missing baryons in the present-day Universe. When compared to observations, the predicted distributions of the different O vi line parameters (column density , Doppler parameter , rest equivalent width Wr) from our simulations exhibit a lack of strong O vi absorbers, a discrepancy that has also been found by Oppenheimer & Dave. This suggests that physical processes on subgrid scales (e.g. turbulence) may strongly influence the observed properties of O vi systems. We find that the intervening O vi absorption arises mainly in highly metal enriched (10−1≪Z/Z⊙≲ 1) gas at typical overdensities of 1 ≪ρ/〈ρ〉≲ 102. One-third of the O vi absorbers in our simulation are found to trace gas at temperatures T < 105 K, while the rest arises in gas at higher temperatures, most of them around T= 105.3 ± 0.5 K. These temperatures are much higher than inferred by Oppenheimer & Dave, probably because that work did not take the suppression of metal-line cooling by the photoionizing background radiation into account. While the O vi resides in a similar region of (ρ, T)-space as much of the shock-heated baryonic matter, the vast majority of this gas has a lower metal content and does not give rise to detectable O vi absorption. As a consequence of the patchy metal distribution, O vi absorbers in our simulations trace only a very small fraction of the cosmic baryons (<2 per cent) and the cosmic metals. Instead, these systems presumably trace previously shock-heated, metal-rich material from galactic winds that is now mixing with the ambient gas and cooling. The common approach of comparing O vi and H i column densities to estimate the physical conditions in intervening absorbers from QSO observations may be misleading, as most of the H i (and most of the gas mass) is not physically connected with the high-metallicity patches that give rise to the O vi absorption.
TEARING THE VEIL: INTERACTION OF THE ORION NEBULA WITH ITS NEUTRAL ENVIRONMENT

We present H i 21 cm observations of the Orion Nebula, obtained with the Karl G. Jansky Very Large Array, at an angular resolution of 7. ″2 × 5. ″7 and a velocity resolution of 0.77 km s−1. Our data reveal H i absorption in the Veil toward the radio continuum of the H ii region, and H i emission arising from the Orion Bar photon-dominated region (PDR) and from the Orion-KL outflow. In the Orion Bar PDR, the H i signal peaks in the same layer as the H2 near-infrared vibrational line emission, in agreement with models of the photodissociation of H2. The gas temperature in this region is approximately 540 K, and the H i abundance in the interclump gas in the PDR is 5%–10% of the available hydrogen nuclei. Most of the gas in this region therefore remains molecular. Mechanical feedback on the Veil manifests itself through the interaction of ionized flow systems in the Orion Nebula, in particular the Herbig-Haro object HH 202, with the Veil. These interactions give rise to prominent blueward velocity shifts of the gas in the Veil. The unambiguous evidence for interaction of this flow system with the Veil shows that the distance between the Veil and the Trapezium stars needs to be revised downward to about 0.4 pc. The depth of the ionized cavity is about 0.7 pc, which is much smaller than the depth and the lateral extent of the Veil. Our results reaffirm the blister model for the M42 H ii region, while also revealing its relation to the neutral environment on a larger scale.
Three-dimensional nanoscale analysis of light-dependent organelle changes in Arabidopsis mesophyll cells

Abstract Different organelles function coordinately in numerous intracellular processes. Photorespiration incidental to photosynthetic carbon fixation is organized across three subcellular compartments: chloroplasts, peroxisomes, and mitochondria. Under light conditions, these three organelles often form a ternary organellar complex in close proximity, suggesting a connection with metabolism during photorespiration. However, due to the heterogeneity of intercellular organelle localization and morphology, organelles' responses to changes in the external environment remain poorly understood. Here, we used array tomography by field emission scanning electron microscopy to image organelles inside the whole plant cell at nanometer resolution, generating a three-dimensional (3D) spatial map of the light-dependent positioning of chloroplasts, peroxisomes, nuclei, and vacuoles. Our results show, in light-treated cells, the volume of peroxisomes increased, and mitochondria were simplified. In addition, the population of free organelles decreased, and the ternary complex centered on chloroplasts increased. Moreover, our results emphasized the expansion of the proximity area rather than the increase in the number of proximity sites interorganelles. All of these phenomena were quantified for the first time on the basis of nanoscale spatial maps. In summary, we provide the first 3D reconstruction of Arabidopsis mesophyll cells, together with nanoscale quantified organelle morphology and their positioning via proximity areas, and then evidence of their light-dependent changes.
Surveilling roads and protecting art

Placing security cameras in buildings, finding good locations for cameras to enforce speed limits or placing guards to defend a border are some of the problems we face everyday. A nation that wishes to defend its border with armed guards wants to be sure the entire border is secure. However, hiring more guards than necessary can be costly. A start-up company moving into a new building wants to be sure every room in the building is seen by some security camera. Cameras are expensive and the company wants to install the smallest number of cameras; at the same time the company wants to be sure the building is secure. These problems, and many other visibility type problems, are not easy to solve in general. In some specific cases, optimal solutions can be obtained quickly. In general, finding an optimal solution may take a very long time. The original results of this thesis address some of these problems. We show some positive results for solving some of these visibility problems. We also give some negative results for some of these problems. These negative results are useful because they tell us that we are unlikely to find a fast algorithm to solve a particular problem optimally. 2 Abstract Approved: Thesis Supervisor Title and Department
Individual Output Voltage Regulation Method of Multifrequency Multireceiver Simultaneous WPT Systems With a Single Inverter

Individual output voltage regulation is an important issue in the multireceiver simultaneous wireless power transfer system. To solve this issue, a novel output voltage regulation method based on a multifrequency modulator and multiple proportional–integral (PI) controllers has been proposed. The proposed modulator combines the improved selected harmonic elimination pulsewidth modulation (SHEPWM) technique and delta-sigma modulation (DSM) technique, which has much less number of switching actions in comparison with the existing multifrequency modulation methods. A continuous-time small-signal model of the system is derived to close the voltage loop. With the proposed method, the output voltages of the system can be regulated individually, continuously, and accurately just using a single inverter and standard receivers. Moreover, the proposed method can be easily extended to the system with more receivers. Finally, the effectiveness of the proposed method is verified experimentally.
PARSIMONIOUS QUASI-UNIFORM ASSOCIATION MODELS APPLIED TO DANISH OCCUPATIONAL MOBILITY DATA

For the well-known Danish occupational mobility data describing, say, the cross classification of father's and son's occupational status categories, the quasi-uniform association (QU) model considered by Goodman (1979, 1981b) fits well. This paper introduces some parsimonious QU models in which the odds of row and/or column effect paprameters pertaining to adjacent categories are given by an exponential func tion. For the Danish data, the parsimonious QU models introduced in this paper are preferable to the original QU model, and new interpretations are made.
A Fast Method for Fitting a Multidimensional Gaussian Function

This paper estimates the multidimensional Gaussian profile parameters from the noisy measurements in the exponential function’s argument domain. The proposed method minimizes the weighted squared error between the natural logarithm of the model and the logarithm of the normalized input data with the weights set to the input data values or model values. The proposed method is an iterative method where the parameters of the covariance matrix and the profile’s peak position are alternatively estimated. The main advantage of the proposed method is a one-step analytical solution for the parameters of the covariance matrix and the linear profile scale for the given initial centroid position for arbitrary dimensions. The profile’s peak position is then updated given the estimated parameters by solving a system of nonlinear coupled equations using an iterative optimization procedure. Finally, the proposed method in the log domain is compared with the LS method in the domain of Gaussian profile values, where all profile parameters are simultaneously estimated using an iterative procedure for solving a system of nonlinear equations using numerical optimization. The proposed log domain estimation method yields similar results as the numerical LS method in the value domain for sufficiently high signal-to-noise ratios (SNRs) and narrow regions-of-interest (ROIs) concerning their precision. However, it converges much faster due to the analytic solution.
IPHAS J062746.41+014811.3: A DEEPLY ECLIPSING INTERMEDIATE POLAR

We present time-resolved photometry of a cataclysmic variable discovered in the Isaac Newton Telescope Photometric Hα Survey of the northern galactic plane, IPHAS J062746.41+014811.3, and classify the system as the fourth deeply eclipsing intermediate polar known with an orbital period of Porb = 8.16 hr and a spin period of Pspin = 2210 s. The system shows mild variations of its brightness that appear to be accompanied by a change in the amplitude of the spin modulation at optical wavelengths and a change in the morphology of the eclipse profile. The inferred magnetic moment of the white dwarf is μwd ∼ (6–7) × 1033 G cm3, and in this case IPHAS J062746.41+014811.3 will evolve either into a short-period EX Hya-like intermediate polar with a large Pspin/Porb ratio or, perhaps more likely, into a synchronized polar. Swift observations show that the system is an ultraviolet and X-ray source, with a hard X-ray spectrum that is consistent with those seen in other intermediate polars. The ultraviolet light curve shows orbital modulation and an eclipse, while the low signal-to-noise ratio X-ray light curve does not show a significant modulation on the spin period. The measured X-ray flux is about an order of magnitude lower than would be expected from scaling by the optical fluxes of well-known X-ray-selected intermediate polars.
LHC diphoton excess in a left-right symmetric model with minimal dark matter

We construct a model containing a viable dark matter candidate, in the framework of left-right symmetry, which can explain both width and cross-section of the observed 750 GeV diphoton excess at the LHC. We introduce a fermion quintuplet whose neutral component can be a possible dark matter candidate, whereas the charged components enhance the loop induced coupling of a 750 GeV singlet scalar with a pair of photons. We study the photo-production of the singlet scalar and its various decay modes, successfully addressing both the ATLAS and the CMS diphoton excess.
Analytic reconstruction of heavy-quark two-point functions at O(α s 3 )

Using a method previously developed, based on the Mellin-Barnes transform, we reconstruct the two-point correlators in the vector, axial, scalar and pseudoscalar channels from the Taylor expansion at q^2=0, the threshold expansion at q^2=4m^2 and the OPE at q^2\rightarrow -\infty, where m is the heavy quark mass. The reconstruction is analytic and systematic and is controlled by an error function which becomes smaller as more terms in those expansions are known.
A possible link between high rotation measure and CSS-GPS sources

We report here the study, in the radio band, of a sample of candidates of high rotation measure (RM). The point-like objects (at kpc scale) were selected by choosing unpolarized sources from the NVSS which show significant linear polarization at 10.45 GHz. Assuming in-band depolarization, this feature suggests the presence of a very dense medium surrounding them in a combination of a strong magnetic field. Further single-dish observations were performed with the 100-m Effelsberg telescope to characterise the SEDs of the sample and to well determine their RM in the 11 to 2 cm wavelength range. Besides, a wideband (L, S, C and X band) full polarisation observational campaign was performed at the JVLA facility. It allows us to analyse the in-band RM for the most extreme objects. Some Effelsberg results and analysis, and preliminary JVLA results are presented. The observations reveal that sources with young, newly growing, radio components at high frequency (i.e. GPS and HFP sources) are characterised by a really dense and/or a magnetised medium that strongly rotates the polarisation angle at the different frequencies, leading to a high RM. (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
TEACHERS’ NARRATIVES FROM INITIAL VIRTUAL CLASSROOMS AND PROFESSIONAL DEVELOPMENT DURING THE COVID-19 PANDEMIC IN DEVELOPING BANGLADESH

In the face of sudden migration to online teaching due to Covid-19 pandemic, education is going under trying times globally, especially in the low resource contexts of the Global South. Little is, however, known about how this forced migration to and coping with emergency remote teaching (ERT) are happening in the low resource context of developing Bangladesh, particularly in the Higher Education (HE). This paper, therefore, aims to understand how virtual classrooms look like in the Higher Education context in Bangladesh through TESOL teachers’ narratives from initial virtual classrooms imparting ERT. Employing narrative inquiry, four teachers from four different public and private universities in Bangladesh share their experiences of doing, undergoing and reflecting as they try to adopt, adapt and strive in imparting ERT and carrying out education in HE. Insights from these initial teacher narratives may inform higher education pedagogies, teacher development in distance education environments in Bangladesh and similar contexts in the Global South. As the paper addresses HE teachers’ initial orientation to ERT without exclusively dealing with TESOL education, it has multidisciplinary approach to migration to and coping with ERT in HE in general.
Strong coupling between a topological qubit and a nanomechanical resonator

We describe a scheme that enables a strong coherent coupling between a topological qubit and the quantized motion of a magnetized nanomechanical resonator. This coupling is achieved by attaching an array of magnetic tips to a namomechanical resonator under a quantum phase controller which coherently controls the energy gap of a topological qubit. Combined with single-qubit rotations the strong coupling enables arbitrary unitary transformations on the hybrid system of topological and mechanical qubits and may pave the way for the quantum information transfer between topological and optical qubits. Numerical simulations show that quantum-state transfer and entanglement distributing between the topological and mechanical qubits may be accomplished with high fidelity.
Constraining blazar distances with combined Fermi and TeV data: An empirical approach

We discuss a method to constrain the distance of blazars with unknown redshift using combined observations in the GeV and TeV regimes. We assume that the Very High Energies (VHE) spectrum corrected for the absorption through the interaction with the extragalactic background light cannot be harder than the spectrum in the Fermi/Large Area Telescope (LAT) band. Starting from the observed VHE spectral data we derive the EBL-corrected spectra as a function of the redshift z and fit them with power laws to be compared with power-law fits to the LAT data. We apply the method to all TeV blazars detected by LAT with known distance and derive an empirical law describing the relation between the upper limits and the true redshifts that can be used to estimate the distance of unknown redshift blazars. Using different EBL models leads to systematic changes in the derived upper limits. Finally, we use this relation to infer the distance of the unknown redshift blazar PKS 1424+240.