Miracle-dz/UniFAR-FTUs huggingface dataset:
A Statistical Study of Nighttime Ionospheric NmF2 Enhancement at Middle‐to‐High Latitudes in the Northern Hemisphere

The electron density in the ionosphere usually continuously decreases during nighttime due to the vanishing of sunlit ionization. However, it sometimes increases unexpectedly, which has been called nighttime ionospheric enhancement. Previous researches studied this type of phenomenon mainly in the low‐to‐middle latitude regions. Here, we investigate the nighttime ionospheric NmF2 enhancement at middle‐to‐high latitudes in the northern hemisphere (NH) during solar cycles 23–24 by analyzing the ionosonde observations at Chilton (51.1°N, 359.4°E, geomagnetic 48.5°N), Juliusruh (54.6°N, 13.4°E, 51.7°N), Tromsø (69.9°N, 19.6°E, 66.9°N), and Qaanaaq (77.5°N, 290.8°E, 84.3°N), as well as comparing with the Empirical Canadian High Arctic Ionospheric Model (E‐CHAIM). The observations show that the nighttime NmF2 enhancement occurs mainly in the winter solstice months (November–February), and the occurrence rate and relative amplitude of the enhancement are inversely related to solar activity. The observed results are in good agreement with the results obtained from E‐CHAIM. Furthermore, the model shows the spatial distribution of the enhancement at the middle‐to‐high latitudes in NH in winter, most obvious in geomagnetic latitude between 50°N and 65°N, and have longitudinal minima centered at 30°W and maxima centered at 120°W and 75°E. From these results, this unique phenomenon at middle latitude is explained probably by the plasma flux from the higher altitudes (e.g., topside ionosphere and plasmasphere) diffusing downward into the ionospheric F2 layer. However, at polar regions, under the influence of the abundant high‐density structures such as polar cap patches, auroral blob, particle precipitation, etc., the F region plasma density enhancement becomes more complicated.
Electronic and piezoelectric properties of BN nanotubes from hybrid density functional method

The electronic and piezoelectric properties of the boron nitride (BN) nanotubes are investigated with the hybrid density functional (B3LYP) method. We first study bulk h-BN and BN sheet and find that the B3LYP band structure and energy gap are consistent with the GW results. The B3LYP band gap is larger than the LDA one by about 1.8 eV for both zigzag and armchair nanotubes with various radius. We give an alternative interpretation that the optical absorption lines at 4.45 eV might be due to the electron transition in small zigzag BN nanotubes. The piezoelectric constant from the B3LYP method for zigzag BN nanotubes are substantially larger than those in the PVDF polymer family, suggesting BN nanotubes as candidates for various nanoelectromechanical applications.
On the two-way interaction between homogeneous turbulence and dispersed solid particles. I: Turbulence modification

The modification of decaying homogeneous turbulence due to its interaction with dispersed small solid particles (d/η<1), at a volumetric loading ratio φv≤5×10−4, is studied using direct numerical simulation. The results show that the particles increase the fluid turbulence energy at high wave numbers. This increase of energy is accompanied by an increase of the viscous dissipation rate, and, hence, an increase in the rate of energy transfer T(k) from the large‐scale motion. Thus, depending on the conditions at particle injection, the fluid turbulence kinetic energy may increase initially. But, in the absence of external sources (shear or buoyancy), the turbulence energy eventually decays faster than in the particle‐free turbulence. In gravitational environment, particles transfer their momentum to the small‐scale motion but in an anisotropic manner. The pressure‐strain correlation acts to remove this anisotropy by transferring energy from the direction of gravity to the other two directions, but at the sa.
Response of Cnidium officinale Makino Plants to Heat Stress and Selection of Superior Clones Using Morphological and Molecular Analysis

Cnidium officinale is a medicinal plant cultivated for its rhizomes, which are used in Chinese, Japanese, and Korean traditional medicine. This medicinal crop is highly susceptible to heat stress and cannot be cultivated in regions of higher temperatures. In the present study, ten clones from Korea (clones 1, 2, 5, 6, 8, 11, 14, 15, 22, and 26) were evaluated for their heat tolerance in vitro at 25, 30, 32.5, and 35 °C, and growth characteristics including plant height, the number of leaves and roots were evaluated. The initial experiment was conducted to find the threshold level for significant damage to the plant, while the second experiment was to screen the germplasm to select heat-tolerant clones. Most of the clones were sensitive to heat stress (clones 1, 2, 8, 11, 14, 15, 22, and 26), and few clones (clones 5 and 6) could perform well at an elevated temperature of 32.5 °C. Molecular analysis of the expression of heat-responsive genes, including heat shock protein (CoHSP), catalase (CoCAT), and cystine protease (CoCP), was performed by quantitative real-time reverse transcriptase polymerase chain reaction (qRT-PCR) carried out with heat-tolerant and heat-sensitive clones. Two of the heat-tolerant clones (clones 5 and 6) showed significant expression of CoHSP and CoCAT genes at elevated temperature treatment. These clones can be used for further evaluation and cultivation.
RELAÇÃO ENTRE ATIVIDADE FÍSICA E OSTEOPOROSE EM MULHERES APÓS A MENOPAUSA EM UM MUNICÍPIO DO INTERIOR DO ESTADO DO RIO GRANDE DO SUL

Este estudo teve o objetivo de relacionar como o histórico de atividades físicas influencia no aparecimento da osteoporose em mulheres no período da pós-menopausa e comparar a qualidade de vida das mesmas. Trata-se de uma investigação quantitativa, descritiva e de campo. Participaram do estudo 46 mulheres. Foram aplicados os questionários Whoqol-Bref e um sociocultural que analisa o histórico de atividade física fracionado por idades. O estudo evidenciou que a prática de atividade física na adolescência confere uma melhor qualidade de vida, postergando o diagnóstico de osteoporose e diminuindo os impactos causados pela doença.
Towards superfluidity of dipolar excitons in a TMDC double layer

We study formation and superfluidity of dipolar excitons in double layer heterostructures formed by two transition metal dichalcogenide (TMDC) atomically thin layers. Considering screening effects for an electron-hole interaction via the harmonic oscillator approximation for the Keldysh potential, the analytical expressions for the exciton energy spectrum and the mean field critical temperature $T_{c}$ for the superfluidity are obtained. It is shown that binding energies of A excitons are larger than for B excitons. The mean field critical temperature for a two-component dilute exciton system in a TMDC double layer is analyzed and shown that latter is an increasing function of the factor $Q$, determined by the effective masses of A and B excitons and their reduced mass. Comparison of the calculations for $T_{c}$ performed by employing the Coulomb and Keldysh interactions demonstrates the importance of screening effects in TMDC.
Higher representations: Confinement and large N

We investigate the confining phase transition as a function of temperature for theories with dynamical fermions in the two index symmetric and antisymmetric representation of the gauge group. By studying the properties of the center of the gauge group we predict for an even number of colors a confining phase transition, if second order, to be in the universality class of Ising in three dimensions. This is due to the fact that the center group symmetry does not break completely for an even number of colors. For an odd number of colors the center group symmetry breaks completely. This pattern remains unaltered at a large number of colors. The confining/deconfining phase transition in these theories at large and finite N is not mapped in the one of super Yang-Mills theory. We extend the Polyakov loop effective theory to describe the confining phase transition of the theories studied here for a generic number of colors. Our results are not modified when adding matter in the same higher dimensional representations of the gauge group. We comment on the interplay between confinement and chiral symmetry in these theories and suggest that they are ideal laboratories to shed light on this issue also formore » ordinary QCD. We compare the free energy as a function of temperature for different theories. We find that the conjectured thermal inequality between the infrared and ultraviolet degrees of freedom computed using the free energy does not lead to new constraints on asymptotically free theories with fermions in higher dimensional representations of the gauge group. Since the center of the gauge group is an important quantity for the confinement properties at zero temperature our results are relevant here as well. « less
Towards femtosecond on-chip electronics

To combine the advantages of ultrafast femtosecond optics with an on-chip communcation scheme, optical signals with a frequency of several hundreds of THz need to be down-converted to coherent electronic signals of GHz or less. So far, this has not been achieved because of the impedance mismatch within electronic circuits and their overall slow response-time. Here, we demonstrate that 14 fs optical pulses in the near-infrared (NIR) can drive electronic on-chip circuits with a bandwidth up to 10 THz. The corresponding electronic pulses propagate in microscopic striplines on a millimeter scale. We exploit femtosecond photoswitches based on tunneling barriers in nanoscale metal junctions to drive the pulses. The non-linear ultrafast response is based on a combination of plasmonically enhanced, multi-photon absorption and quantum tunneling, and gives rise to a field emission of ballistic electrons propagating across the nanoscale junctions. Our results pave the way towards femtosecond electronics integrated in waferscale quantum circuits.
Nonground State Condensates of Ultracold Trapped Atoms

The population dynamics of a trapped Bose-Einstein condensate, subject to the action of an oscillatory field, is studied. This field produces a modulation of the trapping potential with the frequency close to the transition frequency between the ground state and an excited energy level. Unusual critical effects are found exhibiting sharp qualitative changes in the population dynamics. An effective averaged system is constructed explicitly illustrating the occurrence of critical phenomena. The related critical indices are calculated.
Fast Radio Bursts with Extended Gamma-Ray Emission?

We consider some general implications of bright γ-ray counterparts to fast radio bursts (FRBs). We show that even if these manifest in only a fraction of FRBs, γ-ray detections with current satellites (including Swift) can provide stringent constraints on cosmological FRB models. If the energy is drawn from the magnetic energy of a compact object such as a magnetized neutron star, the sources should be nearby and be very rare. If the intergalactic medium is responsible for the observed dispersion measure, the required γ-ray energy is comparable to that of the early afterglow or extended emission of short γ-ray bursts. While this can be reconciled with the rotation energy of compact objects, as expected in many merger scenarios, the prompt outflow that yields the γ-rays is too dense for radio waves to escape. Highly relativistic winds launched in a precursor phase, and forming a wind bubble, may avoid the scattering and absorption limits and could yield FRB emission. Largely independent of source models, we show that detectable radio afterglow emission from γ-ray bright FRBs can reasonably be anticipated. Gravitational wave searches can also be expected to provide useful tests.
A secret sharing scheme on p^2 -dimensional quantum system

In this paper, we give the mutually unbiased bases on the p^2 -dimensional quantum system where p is an odd prime number, and construct the corresponding unitary transformation based on the properties of these mutually unbiased bases. Then, we construct a (N,N) threshold secret sharing scheme using unitary transformation between these mutually unbiased bases, and analyze the scheme's security by several ways, for example, intercept-and-resend attack, entangle-and-measure attack, Trojan horse attack, and so on. Using our method, we construct a single-particle quantum protocol involving only one qudit, and the method shows much more scalability than other schemes.
The disturbing function for polar Centaurs and transneptunian objects

The classical disturbing function of the three-body problem is based on an expansion of the gravitational interaction in the vicinity of nearly coplanar orbits. Consequently, it is not suitable for the identification and study of resonances of the Centaurs and transneptunian objects on nearly polar orbits with the solar system planets. Here, we provide a series expansion algorithm of the gravitational interaction in the vicinity of polar orbits and produce explicitly the disturbing function to fourth order in eccentricity and inclination cosine. The properties of the polar series differ significantly from those of the classical disturbing function: the polar series can model any resonance as the expansion order is not related to the resonance order. The powers of eccentricity and inclination of the force amplitude of a $p$:$q$ resonance do not depend on the value of the resonance order $|p-q|$ but only on its parity. Thus all even resonance order eccentricity amplitudes are $\propto e^2$ and odd ones $\propto e$ to lowest order in eccentricity $e$. With the new findings on the structure of the polar disturbing function and the possible resonant critical arguments, we illustrate the dynamics of the polar resonances 1:3, 3:1, 2:9 and 7:9 where transneptunian object 471325 could currently be locked.
Soft X-Ray Lines and Gas Composition in NGC 1068

Previous X-ray and ultraviolet spectroscopy suggested that the Fe/O abundance ratio in NGC 1068 may be abnormally high. We have tested this suggestion by measuring and modeling the ASCA spectrum of NGC 1068. We have measured some 15 X-ray lines, to an accuracy better than a factor of 2, and modeled the continuum in two different ways. The first assumes that the hard X-ray continuum is the reflection of the nuclear source by two extended, photoionized gas components; a warm (T ~ 1.5 × 105 K) gas and a hot (T ~ 3 × 106 K) gas. All the observed emission lines are produced in this gas, and there is an additional, extended 0.6-3 keV pure continuum component. The model is similar to the one proposed by Marshall et al. (1993). The second model is a combination of a hard reflected continuum with a soft thermal plasma component. The calculations show that the emission lines in the photoionized gas model are in very good agreement with the observed ones assuming solar metallicity for all elements except for iron, which is more than twice solar, and oxygen, which is less than 0.25 solar. Models with solar oxygen are possible if the 0.5-1 keV continuum is weaker, but they do not explain the magnesium and silicon lines. The thermal model fit requires extremely low metallicity (0.04 solar) for all elements. We discuss these findings and compare them with the ASCA spectra of recently observed starburst galaxies. We argue that the apparent low metallicity of starburst galaxies, as well as of the extended nuclear source in NGC 1068, are inconsistent with galaxy chemical evolution. The explanation for this apparent anomaly is still unknown and may involve nonthermal continuum mechanisms and, in some cases, depletion onto grains. Given the strong H-like and He-like lines, as well as the prominent Fe L emission features, the origin of the soft X-ray lines in this source is more likely photoionized gas. We compare our model with the recent Iwasawa, Fabian, & Matt (1997) paper. We also show that fluorescence lines of low-Z elements in AGNs are likely to be stronger than previously assumed.
Making thermodynamic functions of nanosystems intensive

The potential energy of interaction among particles in many systems is proportional to r−α. In systems for which α<d, we encounter nonextensive (nonintensive) thermodynamic functions, where d is the space dimension. A scaling parameter, , has been introduced to make the nonextensive (nonintensive) thermodynamic functions of such systems extensive (intensive). Our simulation results show that this parameter is not capable of making the thermodynamic functions of a nanosystem extensive (intensive). Here we have presented a theoretical justification for . Then we have generalized this scaling parameter to be capable of making the nonextensive (nonintensive) thermodynamic functions of nanosystems extensive (intensive). This generalized parameter is proportional to the potential energy per particle at zero temperature.
The continuum of QSOs and the nature of the broad 3600 A emission feature

Models to explain the shape of the 3600 A blue emission feature in QSO spectra are derived that depend only on a nonthermal, featureless power-law and Balmer continuum from emission-line clouds. These models require a rather flat power-law component with F(v)proportionalv/sup -0.5/ to explain data observed on 3C 273 at visual and ultraviolet wavelengths. The required synchrotron--self-Compton radiation is consistent with X-ray and . gamma. -ray emission. The models are an alternative to those requiring an entirely new component of visual and ultraviolet emission from a thermal accretion region.
Annealing Effect on the Structural, Magnetic, Electrical, Optic Property, Nanomechanical, and Adhesive Characteristics of Co60Fe20Yb20 Thin Films on Glass Substrate

In this study, X-ray diffraction (XRD) analysis showed the amorphous nature of the Co60Fe20Yb20 films deposited at room temperature (RT), 100 °C, and 200 °C. The body-centered cubic (BCC) CoFe (110) characteristic peak was visible at 44.7° after annealing films of 40 nm and 50 nm at 300 °C. The highest alternating current magnetic susceptibility (χac) value was 0.21 at 50 Hz in a 50 nm, and the lowest resistivity value was 1.02 (×10−2 Ω.cm) in a 50 nm. In terms of nano-indication measurement, the highest value of hardness was 9.29 GPa at 300 °C in a 50 nm. When the thickness increased from 10 nm to 50 nm, the hardness and Young’s modulus of the Co60Fe20Yb20 film also showed a saturation trend. The Co60Fe20Yb20 film had the maximum surface energy at 50 nm after 300 °C annealing. The transmittance of Co60Fe20Yb20 films decreased when the thickness was increased because the thickness effect suppresses the photon signal. Due to high χac, low electrical performance, strong nano-mechanical properties, and high adhesion, it was discovered in this work that 50 nm with annealing at 300 °C was the ideal condition for the magnetic and adhesive capabilities of Co60Fe20Yb20 film. More importantly, replacing the CoFeB seed or buffer layer with a thin CoFeYb film improved the thermal stability, making CoFeYb films attractive for practical magnetic tunnel junction (MTJ) applications. Furthermore, the specific properties of Co60Fe20Yb20 films were compared to those of Co60Fe20Y20 films, demonstrating that the specific properties of these two materials may be compared.
Properties of neural networks storing spatially correlated patterns

The author studies the behaviour of a feedforward neural network supplied with spatially organized data. This inner structure is taken into account by a matrix Cij, whose coefficients equal the average correlation between two pixels i and j of the input patterns. The storage capacity alpha is computed as a function of the required stability and of the eigenvalues of C. The author proposes a geometrical transformation allowing an intuitive interpretation of these results. Numerical simulations using real and binary patterns show a very good agreement with the theory. Finally, the author analyses the synaptic couplings correlations resulting from the training of the network with structured patterns. Focusing on exponentially decreasing correlations one and two dimensions, the author finds that they exhibit a 'Mexican hat' profile, the excitatory centre size of which depends on alpha .
STUDIES OF BIPOLAR NEBULAE. VII. THE EXCITING STAR OF OH 0739-14 (= OH 231.8+4.2)

A spectral classification for the exciting star of the bipolar reflection nebula OH 0739-14, which has also been observed to be an OH/H2O maser source, is obtained from the spectrum of the nebulosity in the range 6000-9000 A. Spectrophotometry of the visible nebula was obtained with the Cassegrain image-tube scanner on the Lick Observatory 3-m telescope at a resolution of approximately 7 A. The red spectrum is found to be distinguished by TiO absorption at the bandheads at 8206, 8303, 8432, 8442 and 8452 A and VO in the 7400 and 7900 A regions. On the basis of the depths of these bandheads and the K I 7699 A and Ca II infrared triplet, OH 0739-14 is determined to be of spectral type M9 III. The underlying star thus represents the coolest known star to occur in a bipolar system.
Fast and high-quality tetrahedral mesh generation from neuroanatomical scans

Creating tetrahedral meshes with anatomically accurate surfaces is critically important for a wide range of model-based neuroimaging modalities. However, computationally efficient brain meshing algorithms and software are greatly lacking. Here, we report a fully automated open-source software to rapidly create high-quality tetrahedral meshes from brain segmentations. Built upon various open-source meshing utilities, the proposed meshing workflow allows robust generation of complex head and brain mesh models from multi-label volumes, tissue probability maps, surface meshes and their combinations. The quality of the complex tissue boundaries is preserved through a surface-based approach, allowing fine-grained control over the sizes and quality of the mesh elements through explicit user-defined meshing criteria. The proposed meshing pipeline is highly versatile and compatible with many commonly used brain analysis tools, including SPM, FSL, FreeSurfer, and BrainSuite. With this mesh-generation pipeline, we demonstrate that one can generate 3D full-head meshes that combine scalp, skull, cerebrospinal fluid, gray matter, white matter, and air cavities with a typical processing time of less than 40 seconds. This approach can also incorporate highly detailed cortical and white matter surface meshes derived from FSL and FreeSurfer with tissue segmentation data. Finally, a high-quality brain atlas mesh library for different age groups, ranging from infants to elderlies, was built to demonstrate the robustness of the proposed workflow, as well as to serve as a common platform for simulation-based brain studies. Our open-source meshing software "brain2mesh" and the human brain atlas mesh library can be downloaded at this http URL