Miracle-dz/UniFAR-FTUs huggingface dataset:
A LSB steganography detection algorithm

The spatial LSB steganography results in the alteration of the smooth characteristics between adjoining pixels of the raw image. The relation between the length of embedded message and the gradient energy is theoretically analyzed, and then a steganalysis and detection method, named gradient energy-flipping rate detection (GEFR) is proposed. Through the analysis of the variation of the gradient energy, which results from the LSB steganography in color and grayscale image, the secret message embedded in the target image is detected, and the length of the embedded message is estimated. The method is proved effective and accurate by simulation (detection rate reaches 0.01bit per pixel).
Optimal thresholding in wavelet image compression

Wavelet transform coding has the potential to offer a lot of benefits with respect to image compression and image filtering as well. The later aspect is of importance in machine processing of high entropy images such as Synthetic Aperture Radar images obtained by the European Remote sensing Satellite (ERS-1). A mathematical model is developed to study the relation between a specified Mean Square Error, the value of the wavelet coefficient threshold and the maximum number of resolutions used. The wavelet compression method is compared with other compression methods like JPEG standard and Vector Quantization for a number of different (in a statistical sense) images amongst others LENA.
X-ray spectra of compact extragalactic radio sources

A comparison is conducted of the 0.1-3.5 keV mean power law energy spectral indices (alpha) measured by the Einstein Observatory IPC for (1) 19 low polarization, flat radio spectrum (FRS) core-dominant QSOs; (2) 12 highly polarized QSOs (HPQs); and (3) 24 radio-selected BL Lac objects. Individual spectral fits are presented for several sources for which results are unavailable elsewhere. A maximum-likelihood analysis was used to ascertain the mean power-law index and the standard deviation for each class, under the assumption of a Gaussian intrinsic distribution. The distributions for HPQ and FRS QSOs are similar, in contrast with a small sample of the X-ray-selected BL Lac objects. Implications of these findings for synchrotron self-Compton models are considered. 57 refs.
Mapping lava flow from the Kilauea eruption of 2018 in the east rift zone using space-based synthetic aperture radar

ABSTRACT Lava flows from volcanoes can significantly destroy infrastructure, although they rarely threaten human life. Mapping lava flows is essential to managing the volcanic hazard during eruptions and understanding significant changes in geomorphology after eruptions. In 2018, the eruption of Kilauea, Hawaii’s youngest and most active volcano, destroyed more than 700 homes, farmlands, and roads. Active lava flow tracking is crucial for providing timely warnings to evacuate residents and protect infrastructure. We constructed a map of the lava flow in the East Rift Zone (ERZ) during the Kilauea volcanic eruption in 2018 using remotely sensed satellite synthetic aperture radar observations. We processed 23 C-band Sentinel-1 A/B interferometric wide mode acquisitions captured from May 1 to 17 September 2018 and applied a coherent change detection (CCD) technique to detect minute changes in the target structure. A time series of coherence maps provided detailed spatial information on the movement of the lava flow fields in the ERZ. The overall lava flow map had an area of approximately 33.3 km2 and was verified with a lava thickness map provided by the United States Geological Survey that was generated by two digital elevation models using airborne light detection and ranging observations. Excellent agreement (>90%) among the lava flow observations suggests that the CCD technique is effective in monitoring lava flows during a volcanic eruption.
Effect of Pulsed Electric Field on the Chicken Meat Quality and Taste-Related Amino Acid Stability: Flavor Simulation

Meat contains several amino acids related to taste, which have a significant impact on the overall acceptability of consumers. A number of volatile compounds have been studied in relation to meat flavor, but amino acids have not been fully explored in relation to the taste of raw or cooked meat. It would be interesting to find any changes in physicochemical characteristics, especially the level of taste-active compounds and flavor content during non-thermal processing such as pulsed electric fields (PEF), for commercial reasons. The effect of PEF at low intensity (LPEF; 1 kV/cm) and comparatively high intensity (HPEF; 3 kV/cm) with different pulse numbers (25, 50, and 100) was investigated on the physicochemical characteristics of chicken breast, including the free amino acid content (related to umami, sweet, bitter, or fresh pleasant taste). PEF is regarded as a “nonthermal” technology; however, HPEF induces moderate temperature rises as it increases with the treatment intensity (i.e., electric field strength and pulse number). The pH, shear force, and cook loss (%) of the LPEF and untreated samples were not affected by the treatments, but the shear force of the LPEF and untreated samples was lower than that of HPEF groups that showed PEF-induced slight structural modifications resulting in a more porous cell. In the case of color parameters, the lightness of meat (L*) was significantly higher with treatment intensity, whereas both a* and b* were unaffected by the PEF treatments. Moreover, PEF treatment significantly (p < 0.05) affected umami-related free amino acids (FAAs; glutamic acid and aspartic acid) and leucine and valine, which are precursors of flavor compounds. However, PEF decreases the level of bitter taste contributing FAAs such as lysine and tyrosine, which may prevent the formation of fermented flavors. In conclusion, both PEF treatments (LPEF and HPEF) did not adversely impact the physicochemical quality of chicken breast.
Robust relational trees by scale-space filtering

A relational tree (RT) is a signal representation used to discriminate between multidimensional signals with arbitrary nonlinear monotonic distortion. The use of RTs is limited by noise. Scale-space filtering takes advantage of the inherently scale-like properties of an RT to provide a more robust signal representation across distortions. Some methods and properties of Gaussian scale-space filtering of RTs are examined. Scale trees (STs) and conventionally filtered (fixed-scale) RTs have been shown to be subsets of this process. Since the effect of scale-space filtering is to move segmentation uncertainty toward the leaves of the tree, other operations performed in the tree domain, such as filtering, can be optimized as well. <<ETX>>
The Influence of Home-Based Music Therapy Interventions on Relationship Quality in Couples Living with Dementia—An Adapted Convergent Mixed Methods Study

Relationship quality is important for well-being and quality of life in couples living with dementia. Home-based music therapy interventions may be conducted with the aim of enhancing relationship quality. However, the effects or influences of such interventions are only briefly investigated in previous studies. This study’s aim was to identify how a 12-week home-based music therapy intervention may influence relationship quality in couples living with dementia, through an adapted convergent mixed methods design. In this case, 68 participating couples from the HOMESIDE RCT study, and four individually recruited couples, received the music therapy intervention. Relationship quality for all participants was measured by the standardized Quality of Caregiver-Patient Relationship scale, and qualitative interviews were conducted with the four individually recruited participants at baseline and post intervention. Quantitative analysis indicated no statistically significant intervention effect. However, relationship quality remained stable over the intervention period. The qualitative analysis identified that the music therapy interventions primarily led to positive emotions, closeness, intimacy, and communication between the persons with dementia and their care partners. Intervention influences could also be ambiguous, as sharing music experiences might involve a risk of evoking vulnerabilities or negative emotional responses.
Composite Dietary Antioxidant Index and Plasma Levels of Soluble Klotho: Insights from NHANES

Objectives The association between dietary antioxidants and soluble Klotho (S-Klotho) levels remains unknown. We investigated to explore whether the composite dietary antioxidant index (CDAI) was associated with serum levels of S-Klotho in the middle-aged population. Methods Eligible participants were identified from the National Health and Nutrition Examination Surveys (NHANES) from 2007 until 2016. The CDAI was calculated from the intake of six dietary antioxidants. The serum levels of S-Klotho were measured via enzyme-linked immunosorbent assay (ELISA). Generalized linear and nonlinear models were established to analyze the relationship between CDAI and S-Klotho levels. Results Based on the S-Klotho quartiles, S-Klotho levels were higher in young women, Blacks, higher education, never smokers, lower waistlines, no medication use, and those with higher CDAI. Univariate analysis revealed that age, gender, race, smoking status, body mass index, waistline, and medication use were associated with serum levels of S-Klotho. When potential confounders were controlled, CDAI was significantly associated with S-Klotho levels. Subgroup analysis also revealed that this association remained significant in individuals who had the highest quartiles of CDAI, aged population (>60 years), male, and never smoker. A nonlinear relationship was observed between the CDAI and S-Klotho plasma concentrations. Conclusion CDAI was positively correlated with plasma levels of S-Klotho after controlling for covariates. Further studies are needed to validate the current findings and explore the fundamental mechanisms.
Existence of transverse waves in anisotropic poroelastic media

SUMMARY Out of the four waves in an anisotropic poroelastic medium, two are termed as quasi-transverse waves. The prefix ‘quasi’ refers to their polarizations being nearly, but not exactly, perpendicular to direction of propagation. In this composite medium, unlike perfectly elastic medium, the propagation of a longitudinal wave along a phase direction may not be accompanied by transverse waves. The existence of a transverse wave in anisotropic poroelastic media is ensured by the two equations restricting the choice of elastic coefficients of porous aggregate as well as fluid–solid coupling. Necessary and sufficient conditions for the existence of transverse waves along the coordinate axes and in the coordinate planes for general anisotropy are discussed. The discussion is extended to the case of orthotropic materials and existence for few specific phase directions is also explored. The conditions for the transverse waves decided on the basis of their apparent polarizations, that is, particle motion being perpendicular to ray direction, are also discussed. For a particular numerical model, the existence of these apparent transverse waves is solved numerically for phase directions in coordinate planes. For general directions of phase propagation, the existence of these transverse waves is checked graphically for the chosen numerical model.
High-Selectivity Frequency-Selective Rasorber With Tunable Absorptivity

This article presents a high-selectivity frequency-selective rasorber (FSR) with an adjustable out-band absorptivity property. This rasorber is composed of a dynamic absorptive frequency-selective surface (AFSS) on the top, with p-i-n diodes employed to achieve tunable absorptivity, and a high-quality ( $Q$ )-factor bandpass FSS in the bottom, with an aperture-coupled resonators (ACRs) structure to obtain a high-selectivity transparent window. To begin with, theoretical analyses and extensive simulations are performed to evaluate the performance. Subsequently, a prototype is fabricated and measured, showing a 1 dB transmission window with high selectivity at 8.43–8.51 GHz and electrical tuning on the absorption rate response with a wide tunable span of 0.9 at out bands of 4.43–7.76 and 9.21–13.45 GHz, respectively. The proposed rasorber with dynamic tunability of absorptivity can provide radar cross Section (RCS) consistent with the environment, which is potential for radar stealth, deception, and anti-identification.
On the Uniformity of Distribution of the Elliptic Curve ElGamal Signature

We show that, under some natural conditions, the pairs (@r, @s) produced by the elliptic curve ElGamal signature scheme are uniformly distributed. In particular, this implies that values of @r and @s are not correlated. The result is based on some new estimates of exponential sums. For the ElGamal signature over a finite field, a similar result has been obtained by the second author.
Quantum chemistry simulations in an undergraduate project: tellurophenes as narrow bandgap semiconductor materials

The convenient graphical user-interfaces now available with advanced simulation software offer a powerful didactic tool for research-led teaching of methods in quantum chemistry and wider applications of quantum mechanics. In the student project work reported here, a homologous series of semiconducting chalcogenophenes (encompassing poly-thiophenes, poly-selenophenes and poly-tellurophenes) with varying polymer chain lengths were simulated in detail using density functional theory (DFT). Following geometry optimization, energy calculations reveal that increasing the length of the polymer chain (N) from a monomer to a hexamer leads to a narrowing and large-N convergence of the bandgap. It is found that hexa-tellurophene has significantly favourable electronic properties as compared to the other analogues, with a greatly enhanced electron affinity (−2.74 eV), and a corresponding bandgap energy of 2.18 eV, giving a superior matching to the solar spectrum.
The size distribution of interstellar grains

Three major areas involving interstellar grains were investigated. First, studies were performed of scattering in reflection nebulae with the goal of deriving scattering characteristics of dust grains such as the albedo and the phase function asymmetry throughout the visible and the ultraviolet. Secondly, studies were performed of the wavelength dependence of interstellar extinction designed to demonstrate the wide range of grain size distributions naturally occurring in individual clouds in different parts of the galaxy. And thirdly, studies were also performed of the ultraviolet powered emission of dust grains in the 0.5 to 1.0 micron wavelength range in reflection nebulae. Findings considered of major importance are highlighted.
Theoretical study of thermal and magneto‐electronic properties of YbX2 (X = Co and Fe) intermetallic compounds

In this study, we reported the electronic structure, magnetic stability and thermal properties of the YbCo2 and YbFe2 compounds using the density functional (DFT) full‐potential linearized augmented plane wave (FP‐LAPW) method. We applied in this computation the Hubbard potential (U) on the strongly correlated atoms. The band structures (BS), the density of states (DOS) and the charge densities of these compounds were projected. Moreover, we have calculated the thermal parameters for different values of temperatures and pressures. This work shows a comparative study using both GGA and GGA + U schemes. It is important to note that these compounds are potential candidates in the hydrogen storage applications. To our knowledge, the calculated of the thermodynamic characteristics have not yet been computed; hence, our results serve as a prediction for future applications and research.
Experimental study of turbulence in plane separated flows

Some recent attempts at predicting turbulent twodimensional recirculating flows have concentrated on modelling the turbulent energy equations used in the finite difference analysis methods of solutions of the elliptic partial differential equations governing these flows. These attempts have to some extent been restricted by the lack of experimental studies of the high turbulence intensities found in separated flows. The improvement of the pulsed hot-wire anemometer and the laser Doppler anemometer have made possible such studies and this paper describes an investigation using the laser Doppler anemometer in a separated flow situa­ tion. Results are given of an experimental study of the plane turbulent separated flow of water over a double backward facing step of duct height ratio 3:1. Time mean streamwise, transverse and cross-stream com­ ponents of velocity are reported, together with the turbulent velocity fluctuations. The measurements were made using a laser Doppler anemometer operating in the differential Doppler mode with forward scattering. The problem of high turbulence intensity and instantaneous flow reversals was overcome by frequency shifting of the incident laser light beams using a pair of Bragg cells. Substantial changes in flow patterns were detected together with turbulence intensities based on local streamwise velocity of up to 100% were recorded in the recirculating zones. Trans­ verse turbulence intensities were in general about half that of the streamwise components, with cross-stream intensities an order of magnitude lower again.
Application of Ionic Liquids as Mobile Phase Additives for Simultaneous Analysis of Nicotine and Its Metabolite Cotinine in Human Plasma by HPLC–DAD

Nicotine and cotinine are very polar basic molecules, which makes it difficult to analyze them by reversed-phase liquid chromatography (RPLC), especially in biological samples. Additives with an ionic character have been traditionally used in RPLC as silanol suppressors. The aim of our study was to investigate the potential of selected ionic liquids in improving chromatographic performance in comparison with common additives. The experimental design was conducted using the following ionic liquids as the mobile phase modifiers: 1-butyl-3-methylimidazolium tetrafluoroborate, BMIM[BF4] and 1-butyl-3-methylimidazolium hexafluorophosphate BMIM[PF6], with a C18 chromatographic column. The separation of these alkaloids on silica-based RPLC stationary phases was successfully conducted by the addition of BMIM[BF4] in an acetonitrile:phosphate-buffer-based mobile phase in a pH range of 2.3–5.2. The presented chromatographic method can be used as alternative for monitoring studies or pharmacokinetic application necessary for the evaluation of tobacco smoke exposure.
Prestack wavefield approximations

ABSTRACTThe double-square-root (DSR) relation offers a platform to perform prestack imaging using an extended single wavefield that honors the geometrical configuration between sources, receivers, and the image point, or in other words, prestack wavefields. Extrapolating such wavefields, nevertheless, suffers from limitations. Chief among them is the singularity associated with horizontally propagating waves. I have devised highly accurate approximations free of such singularities which are highly accurate. Specifically, I use Pade expansions with denominators given by a power series that is an order lower than that of the numerator, and thus, introduce a free variable to balance the series order and normalize the singularity. For the higher-order Pade approximation, the errors are negligible. Additional simplifications, like recasting the DSR formula as a function of scattering angle, allow for a singularity free form that is useful for constant-angle-gather imaging. A dynamic form of this DSR formula ca.
Exchange-correlation kernel in time-dependent density functional theory

In time-dependent density-functional theory, an important quantity is the exchange-correlation kernel whose knowledge allows for the calculations of the excitation spectrum of electronic systems. In most applications, the exchange-correlation kernel is approximated by the adiabatic local-density approximation, ignoring the frequency dependence and nonlocality. To gain insight into the nature of the exact exchange-correlation kernel, we have considered a two-dimensional one-band Hubbard model. The calculated exact exchange-correlation kernel reveals a number of striking features. It has a weak energy dependence up to the main excitation energy. On the other hand, the exact kernel shows a strong energy dependence in energy regions, where there are many-body excitations that are not contained in the local-density approximation, even though these excitations have small weight. It is found that a static approximation can well reproduce the main excitation peaks, but the satellite structures arising from many-body interaction are unlikely to be accounted for with a static approximation.
Coherent scatter x-ray imaging of plastic/water phantoms

Conventional medical x-ray imaging, based on the transmission of primary photons, works well to distinguish between hard and soft tissues. Up to 90% of the photons that reach the image receptor, however, are coherently or incoherently scattered, and so there is growing interest in utilizing scattered x rays for diagnosis. The semi-analytical model developed by our group predicts better contrast and signal-to-noise ratio for scatter imaging than for primary for some diagnostic examinations such as distinguishing white versus gray brain matter, and for mammography. Low-angle scattered photons can only be distinguished from primary on the basis of direction and consequently a well-collimated x-ray system is required. A hexagonal array of seven 1.5 mm diameter pinholes is designed and tested to record the diffraction pattern of plastic and water phantoms. These materials are amorphous solids and result in rotationally-symmetric diffraction patterns which are characteristic of the materials. The intensities of the diffraction patterns are numerically integrated over concentric rings and the scatter images are made by assigning the ring sums as the pixel values. For these measurements the tube is operated with technique factors ranging from 70 kV 2500 mAs to 120 kV 500 mAs. The scatter patterns are recorded on a storage phosphor image plate. Test images are made of 1 cm thick targets in air and in a water tank. The ultimate goal is to make scatter images of different kinds of tissues for better diagnostic information.
Single-frequency operation of a diode-pumped green laser using multi-Brewster plates

In a diode-pumped, KTP intracavity frequency-doubled green laser, multi-Brewster plates are used to achieve high power single-frequency operation. With a simple experimental setup, single-frequency operation of the diode-pumped green laser with output of 46 and 218 mW is obtained by one and three Brewster plate, respectively.
Effect of doping on the magnetic properties of GaMnN: Fermi level engineering

GaMnN dilute magnetic semiconductor samples, prepared by metalorganic chemical vapor deposition, are shown to exhibit ferromagnetism or even paramagnetism depending upon the type and concentration of extrinsic impurity present in the film. In addition, GaMnN deposited using growth parameters normally yielding a nonferromagnetic film becomes strongly ferromagnetic with the addition of magnesium, an acceptor dopant. Based upon these observations, it seems that ferromagnetism in this material system depends on the relative position of the Mn energy band and the Fermi level within the GaMnN band gap. Only when the Fermi level closely coincides with the Mn-energy level is ferromagnetism achieved. By actively engineering the Fermi energy to be within or near the Mn energy band, room temperature ferromagnetism is realized.