Miracle-dz/UniFAR-FTUs huggingface dataset:
Design of RF Power Amplifiers Using Parallel-Series Power Combining Transformers

This paper presents the design of a one watt-level RF CMOS Power Amplifier (PA) based on power combining transformers PSCT in 0.13 µm technology using ADS 2011.10. The PA incorporates a parallel combination of four differential PA cores to generate high output power with acceptable efficiency and linearity. The first part the design for class-AB PA for WLAN applications is presented. The PA delivers an Output Power (Pout) of 30 dBm, Power Gain (Gp) of 30 dB and 40% PAE using 2.5 V supply. In the second part a class-E PA is designed to provide an output power of 30 dBm, power gain of 30 dB, and 54% PAE at 2.45 GHz using 1.6 V supply. The layout of the transformers is designed and simulated with momentum RF EM simulator of ADS 2011.10 in order to realize a fully integrated power amplifier. The simulated efficiency of the designed transformer was 78% with minimum insertion losses ( ILmin ) of 0.87 dB.
Isolation of a New Polysaccharide from Dandelion Leaves and Evaluation of Its Antioxidant, Antibacterial, and Anticancer Activities

Dandelion, in China, has a long history as a medicinal and edible plant, and possesses high nutritional and medical value. The present study aimed to isolate a new polysaccharide (DLP-3) from dandelion leaves and to evaluate its antioxidant, antibacterial, and anticancer activities. The structure of DLP-3 was analyzed using HPLC, FT-IR, SEM, GC-MS, and NMR spectroscopy. DLP-3 mainly consisted of Man, Rha, GlcA, Glc, Gal, and Ara with molar ratios of 2.32, 0.87, 1.21, 3.84, 1.00, and 1.05, respectively, with a molecular weight of 43.2 kDa. The main linkages of DLP-3 contained (1→4)-α-d-Glc, (1→4,6)-α-d-Glc, (1→6)-α-d-Gal, (1→2)-α-d-Man, (1→4)-α-d-Man, β-l-Ara-(1→, and α-l-Rha-(1→. DLP-3 exhibited a smooth surface, purely flake-like structure, and a triple helix conformation. Moreover, DLP-3 presented obvious antioxidant and antibacterial activities in a concentration-dependent manner. DLP-3 showed significant anticancer activities by inhibiting tumor cell proliferation. These findings provide a theoretical basis for the application of DLP-3 as a natural functional active substance in functional foods.
THREE-DIMENSIONAL SIMULATIONS OF THE THERMAL X-RAY EMISSION FROM YOUNG SUPERNOVA REMNANTS INCLUDING EFFICIENT PARTICLE ACCELERATION

Supernova remnants (SNRs) are believed to be the major contributors to Galactic cosmic rays. The detection of non-thermal emission from SNRs demonstrates the presence of energetic particles, but direct signatures of protons and other ions remain elusive. If these particles receive a sizeable fraction of the explosion energy, the morphological and spectral evolution of the SNR must be modified. To assess this, we run three-dimensional hydrodynamic simulations of a remnant coupled with a nonlinear acceleration model. We obtain the time-dependent evolution of the shocked structure, impacted by the Rayleigh–Taylor hydrodynamic instabilities at the contact discontinuity and by the back-reaction of particles at the forward shock. We then compute the progressive temperature equilibration and non-equilibrium ionization state of the plasma, and its thermal emission in each cell. This allows us to produce the first realistic synthetic maps of the projected X-ray emission from the SNR. Plasma conditions (temperature and ionization age) can vary widely over the projected surface of the SNR, especially between the ejecta and the ambient medium owing to their different composition. This demonstrates the need for spatially resolved spectroscopy. We find that the integrated emission is reduced with particle back-reaction, with the effect being more significant for the highest photon energies. Therefore, different energy bands, corresponding to different emitting elements, probe different levels of the impact of particle acceleration. Our work provides a framework for the interpretation of SNR observations with current X-ray missions (Chandra, XMM-Newton, and Suzaku) and with upcoming X-ray missions (such as Astro-H).
EVOLUTION OF MASSIVE PROTOSTARS VIA DISK ACCRETION

Mass accretion onto (proto-)stars at high accretion rates 10^{-4}\, M_{\odot }\,{\rm yr}^{-1}$? > is expected in massive star formation. We study the evolution of massive protostars at such high rates by numerically solving the stellar structure equations. In this paper, we examine the evolution via disk accretion. We consider a limiting case of “cold” disk accretion, whereby most of the stellar photosphere can radiate freely with negligible backwarming from the accretion flow, and the accreting material settles onto the star with the same specific entropy as the photosphere. We compare our results to the calculated evolution via spherically symmetric accretion, the opposite limit, whereby the material accreting onto the star contains the entropy produced in the accretion shock front. We examine how different accretion geometries affect the evolution of massive protostars. For cold disk accretion at 10−3 M☉ yr−1, the radius of a protostar is initially small, R*≃ a few R☉. After several solar masses have accreted, the protostar begins to bloat up and for M* ≃ 10 M☉ the stellar radius attains its maximum of 30–400 R☉. The large radius ∼100 R☉ is also a feature of spherically symmetric accretion at the same accreted mass and accretion rate. Hence, expansion to a large radius is a robust feature of accreting massive protostars. At later times, the protostar eventually begins to contract and reaches the zero-age main sequence (ZAMS) for M* ≃ 30 M☉, independent of the accretion geometry. For accretion rates exceeding several 10−3 M☉ yr−1, the protostar never contracts to the ZAMS. The very large radius of several hundreds R☉ results in the low effective temperature and low UV luminosity of the protostar. Such bloated protostars could well explain the existence of bright high-mass protostellar objects, which lack detectable H ii regions.
Are Attitudes towards COVID-19 Pandemic Related to Subjective Physical and Mental Health?

In this paper, we investigate the relationship between a person’s psychological distress, subjective physical health and their attitudes towards the COVID-19 pandemic. The evaluation was performed on the basis of data from two waves of the Saxon Longitudinal Study, carried out in 2019 (pre-pandemic) and 2021. The number of study participants in both waves was 291. We tested in autoregressive cross-lagged models the stability of the respondents’ health status before and during the pandemic and reviewed their influence on attitudes towards COVID-19. Our results show that COVID-19-related concerns are controlled by subjective physical health, while pandemic denial is linked to psychological distress. In an unknown and critical situation, with limited control over the situation, the strategy of avoidance or suppression may be used by individuals for protection by psychologically downplaying the stressor and danger.
On the application of conformers to logical access voice spoofing attack detection

Biometric systems are exposed to spoofing attacks which may compromise their security, and automatic speaker verification (ASV) is no exception. To increase the robustness against such attacks, anti-spoofing systems have been proposed for the detection of spoofed audio attacks. However, most of these systems can not capture long-term feature dependencies and can only extract local features. While transformers are an excellent solution for the exploitation of these long-distance correlations, they may degrade local details. On the contrary, convolutional neural networks (CNNs) are a powerful tool for extracting local features but not so much for capturing global representations. The conformer is a model that combines the best of both techniques, CNNs and transformers, to model both local and global dependencies and has been used for speech recognition achieving state-of-the-art performance. While conformers have been mainly applied to sequence-to-sequence problems, in this work we make a preliminary study of their adaptation to a binary classification task such as anti-spoofing, with focus on synthesis and voice-conversion-based attacks. To evaluate our proposals, experiments were carried out on the ASVspoof 2019 logical access database. The experimental results show that the proposed system can obtain encouraging results, although more research will be required in order to outperform other state-of-the-art systems.
Large-N reduction for N=2 quiver Chern-Simons theories on S^3 and localization in matrix models

We study reduced matrix models obtained by the dimensional reduction of N=2 quiver Chern-Simons theories on S^3 to zero dimension and show that if a reduced model is expanded around a particular multiple fuzzy sphere background, it becomes equivalent to the original theory on S^3 in the large-N limit. This is regarded as a novel large-N reduction on a curved space S^3. We perform the localization method to the reduced model and compute the free energy and the vacuum expectation value of a BPS Wilson loop operator. In the large-N limit, we find an exact agreement between these results and those in the original theory on S^3.
Intelligent Single-Cavity Dual-Comb Source With Fast Locking

Dual-comb source (DCS) generation occupies the central position to the versatilities of dual-comb applications. The single-cavity-based DCS generation is an emerging technology which provides superior mutual coherence between the two combs by sharing one laser cavity, therefore sophisticated active stabilization approaches are not necessary. However, the condition for starting and stabilizing dual-comb mode-locking in a single cavity is critical which hinder this technology towards practical applications. To resolve the bottleneck, we experimentally demonstrate the first intelligent single-cavity DCS by combining the real-time intelligent control module with the memory-aided intelligent searching algorithm. Given a tremendous six-dimensional parametric space, the intelligent DCS can operate under the dual-comb regime from a continuous wave state within a mean time of only 2.48 seconds. The dual-comb mode-locking state can be recovered automatically after interruption. The long-term stability of the intelligent DCS is validated as well through a 12-hour test in an open environment.
A PROPELLER-EFFECT INTERPRETATION OF MAXI/GSC LIGHT CURVES OF 4U 1608−52 AND Aql X-1 AND APPLICATION TO XTE J1701−462

We present the luminosity dwell-time distributions during the hard states of two low-mass X-ray binaries containing a neutron star (NS), 4U 1608−52 and Aql X-1, observed with MAXI/GSC. The luminosity distributions show a steep cutoff on the low-luminosity side at ∼1.0 × 1036 erg s−1 in both sources. The cutoff implies a rapid luminosity decrease in their outburst decay phases and this decrease can be interpreted as being due to the propeller effect. We estimate the surface magnetic field of 4U 1608−52 to be (0.5–1.6) × 108 G and Aql X-1 to be (0.6–1.9) × 108 G from the cutoff luminosity and apply the same propeller mechanism to the similar rapid luminosity decrease observed in the transient Z source, XTE J1701−462, with RXTE/ASM. Assuming that the spin period of the NS is on the order of milliseconds, the observed cutoff luminosity implies a surface magnetic field on the order of 109 G.
Investigating the crowd-drawing effect, on passersby, of pseudo-crowds using multiple robots

Due to their conversational skills, service robots are expected to replace posters or digital signage as a new advertising medium. These robots must achieve two goals to obtain maximum advertising opportunities in a public space: they must stop as many passersby as possible and make passersby stay as long as possible. In previous studies, to achieve these goals, the robots called out to each passerby one by one, which was inefficient as an advertising medium. Therefore, to obtain more advertising opportunities, this study proposes a method to simultaneously stop many passersby and make them stay, by creating a pseudo-crowd with multiple robots. The pseudo-crowd is a system in which multiple robots acting as an audience are placed around a robot providing information. We verified the effectiveness of the proposed method in a shopping mall. As a result, increasing the number of robots made more passersby stop, and the use of audience robots extended the time passersby spent in front of the robots. Our findings will contribute to the application of robots as a more useful advertising medium in public spaces. GRAPHICAL ABSTRACT
Testing reanalysis data sets in Antarctica: Trends, persistence properties, and trend significance

The reanalysis data sets provide important sources for investigating the climate in Antarctica where stations are sparse. In this paper, we compare the 2 m near‐surface temperature data from five major reanalysis data sets with observational Antarctic stations data over the last 36 years: (i) the National Centers for Environmental Prediction and the National Center for Atmospheric Research Reanalysis (NCEP1), (ii) NCEP‐DOE Reanalysis 2 (NCEP2), (iii) the European Centre for Medium‐Range Weather Forecasts Interim Reanalysis (ERA‐Interim), (iv) the Japanese 55 year Reanalysis (JRA‐55), and (v) the National Aeronautics and Space Administration Modern‐Era Retrospective‐analysis for Research and Applications. In our assessment, we compare (a) the annual and seasonal trends obtained by linear regression analysis, (b) the standard deviation around the annual trends, (c) the detrended lag‐1‐autocorrelation C(1), (d) the Hurst exponent α that characterizes the long‐term memory in a record, and (e) the significance levels of the warming/cooling trends. We find that all five reanalysis data sets are able to reproduce quite well the long‐term memory in the instrumental data. In contrast, C(1), which is needed as input for the conventional significance analysis, shows fully erratic behavior. The observational warming/cooling trends in East and West Antarctica are not reproduced well by all reanalysis data sets, in particular, NCEP1, NCEP2, and JRA‐55 show spurious warming trends in many parts of East Antarctica, even in those parts where cooling has been observed. In contrast, the standard deviation around the trends is quite well reproduced by all reanalysis data sets. In the peninsula where the station density is quite high, the performance of the reanalysis data is considerably better. It is remarkable that all reanalysis data sets as well as the observational data show (under the assumption of a long‐term persistent process) that in the considered time period since 1979 the warming in the peninsula is not significant with p values well above 0.1.
THE APPLICATION OF MULTIVIEW METHODS FOR HIGH-PRECISION ASTROMETRIC SPACE VLBI AT LOW FREQUENCIES

High-precision astrometric space very long baseline interferometry (S-VLBI) at the low end of the conventional frequency range, i.e., 20 cm, is a requirement for a number of high-priority science goals. These are headlined by obtaining trigonometric parallax distances to pulsars in pulsar–black hole pairs and OH masers anywhere in the Milky Way and the Magellanic Clouds. We propose a solution for the most difficult technical problems in S-VLBI by the MultiView approach where multiple sources, separated by several degrees on the sky, are observed simultaneously. We simulated a number of challenging S-VLBI configurations, with orbit errors up to 8 m in size and with ionospheric atmospheres consistent with poor conditions. In these simulations we performed MultiView analysis to achieve the required science goals. This approach removes the need for beam switching requiring a Control Moment Gyro, and the space and ground infrastructure required for high-quality orbit reconstruction of a space-based radio telescope. This will dramatically reduce the complexity of S-VLBI missions which implement the phase-referencing technique.
Colliding clouds of strongly interacting spin-polarized fermions

Motivated by a recent experiment at MIT, we consider the collision of two clouds of spin-polarized atomic Fermi gases close to a Feshbach resonance. We explain why two dilute gas clouds, with underlying attractive interactions between their constituents, bounce off each other in the strongly interacting regime. Our hydrodynamic analysis, in excellent agreement with experiment, gives strong evidence for a metastable many-body state with effective repulsive interactions.
Viable Twin Cosmology from Neutrino Mixing

Twin Higgs models solve the little hierarchy problem without introducing new colored particles, however they are often in tension with measurements of the radiation density at late times. Here we explore viable cosmological histories for Twin Higgs models. In particular, we show that mixing between the SM and twin neutrinos can thermalize the two sectors below the twin QCD phase transition, significantly reducing the twin sector's contribution to the radiation density. The requisite twin neutrino masses of order 1-20 GeV and mixing angle with SM neutrinos of 10^{-3} - 10^{-5} can be probed in a variety of current and planned experiments. We further find that these parameters can be naturally accessed in a warped UV completion, where the neutrino sector can also generate the Z2-breaking Higgs mass term needed to produce the hierarchy between the symmetry breaking scales f and v.
The non-symmetric ion-atom radiative processes in the stellar atmospheres

The aim of this research is to show that the processes of absorption charge exchange and photoassociation in A + B + collisions together with the processes of AB + photodissociation in the case of strongly non-symmetric ion–atom systems, significantly influence the opacity of stellar atmospheres in ultraviolet (UV) and extreme UV (EUV) region. In this work, the significance of such processes for solar atmosphere is studied. In the case of the solar atmosphere the absorption processes with A = H and B = Mg and Si are treated as dominant ones, but the cases A = H and B = Al and A = He and B = H are also taken into consideration. The choice of just these species is caused by the fact that, of the species relevant for the used solar atmosphere model, it was only for them that we could determine the necessary characteristics of the corresponding molecular ions, i.e. the molecular potential curves and dipole matrix elements. It is shown that the efficiency of the examined non-symmetric processes within the rather wide corresponding quasi-molecular absorption bands in the far-UV and EUV regions is comparable and sometimes even greater than the intensity of the known symmetric ion–atom absorption processes, which are included now in the models of the solar atmosphere. Consequently, the presented results suggest that the non-symmetric ion–atom absorption processes also have to be included ab initio in the corresponding models of the stellar atmospheres.
The 6dF Galaxy Survey: z \approx 0 measurement of the growth rate and sigma_8

We present a detailed analysis of redshift-space distortions in the two-point correlation function of the 6dF Galaxy Survey (6dFGS). The K-band selected sub-sample which we employ in this study contains 81971 galaxies distributed over 17000deg^2 with an effective redshift z = 0.067. By modelling the 2D galaxy correlation function, xi(r_p,pi), we measure the parameter combination f(z)sigma_8(z) = 0.423 +/- 0.055. Alternatively, by assuming standard gravity we can break the degeneracy between sigma_8 and the galaxy bias parameter, b. Combining our data with the Hubble constant prior from Riess et al (2011), we measure sigma_8 = 0.76 +/- 0.11 and Omega_m = 0.250 +/- 0.022, consistent with constraints from other galaxy surveys and the Cosmic Microwave Background data from WMAP7. Combining our measurement of fsigma_8 with WMAP7 allows us to test the relationship between matter and gravity on cosmic scales by constraining the growth index of density fluctuations, gamma. Using only 6dFGS and WMAP7 data we find gamma = 0.547 +/- 0.088, consistent with the prediction of General Relativity. We note that because of the low effective redshift of 6dFGS our measurement of the growth rate is independent of the fiducial cosmological model (Alcock-Paczynski effect). We also show that our conclusions are not sensitive to the model adopted for non-linear redshift-space distortions. Using a Fisher matrix analysis we report predictions for constraints on fsigma_8 for the WALLABY survey and the proposed TAIPAN survey. The WALLABY survey will be able to measure fsigma_8 with a precision of 4-10%, depending on the modelling of non-linear structure formation. This is comparable to the predicted precision for the best redshift bins of the Baryon Oscillation Spectroscopic Survey (BOSS), demonstrating that low-redshift surveys have a significant role to play in future tests of dark energy and modified gravity.
Gravitational lensing effects on submillimetre galaxy counts

We study the effects on the number counts of submillimetre galaxies due to gravitational lensing. We explore the effects on the magnification cross-section due to halo density profiles, ellipticity and cosmological parameter (the power-spectrum normalization sigma(8)). We show that the ellipticity does not strongly affect the magnification cross-section in gravitational lensing while the halo radial profiles do. Since the baryonic cooling effect is stronger in galaxies than clusters, galactic haloes are more concentrated. In light of this, a new scenario of two-halo-population model is explored where galaxies are modelled as a singular isothermal sphere profile and clusters as a Navarro, Frenk and White profile. We find that the transition mass between the two has modest effects on the lensing probability. The cosmological parameter sigma(8) alters the abundance of haloes and therefore affects our results. Compared with other methods, our model is simpler and more realistic. The conclusions of previous works confirm that gravitational lensing is a natural explanation for the number count excess at the bright end.
Unusual sensitivity of superconductivity to strain in iron-based 122 superconductors

Co-doped BaFe2As2 has been previously shown to have an unusually significant improvement of Tc (up to 2 K, or almost 10%) with annealing 1-2 weeks at 700 or 800 C, where such annealing conditions are insufficient to allow significant atomic diffusion. While confirming similar behavior in optimally Co-doped SrFe2As2 samples, the influence on Tc of strain induced by grinding to ~50 micron sized particles, followed by pressing the powder into a pellet using 10 kbar pressure, was found to increase the annealed transition width of 1.5 K by approximately a factor of ten. Also, the bulk discontinuity in the specific heat at Tc, deltaC, on the same pellet sample was completely suppressed by grinding. This evidence for a strong sensitivity of superconductivity to strain was used to optimize single crystal growth of Co-doped BaFe2As2. This strong dependence (both positive via annealing and negative via grinding) of superconductivity on strain in these two iron based 122 structure superconductors is compared to the unconventional heavy Fermion superconductor UPt3, where grinding is known to completely suppress superconductivity, and to recent reports of strong sensitivity of Tc to damage induced by electron-irradiation-induced point defects in other 122 structure iron-based superconductors, Ba(Fe0.76Ru0.24)2As2 and Ba1-xKxFe2As2. Both the electron irradiation and the introduction of strain by grinding are believed to only introduce non-magnetic defects, and argue for unconventional superconducting pairing.