Miracle-dz/UniFAR-FTUs huggingface dataset:
Coulomb blockade directional coupler

A tunable directional coupler based on Coulomb blockade effect is presented. Two electron waveguides are coupled by a quantum dot to an injector waveguide. Electron confinement is obtained by surface Schottky gates on a single GaAs∕AlGaAs heterojunction. Magneto-electrical measurements down to 350mK are presented and large transconductance oscillations are reported on both outputs up to 4.2K. Experimental results are interpreted in terms of Coulomb blockade effect and the relevance of the present design strategy for the implementation of an electronic multiplexer is underlined.
Prompt Gamma Ray Burst emission from gradual magnetic dissipation

We considered a model for the prompt phase of Gamma-Ray Burst (GRB) emission arising from a magnetized jet undergoing gradual energy dissipation due to magnetic reconnection. The dissipated magnetic energy is translated to bulk kinetic energy and to acceleration of particles. The energy in these particles is released via synchrotron radiation as they gyrate around the strong magnetic fields in the jet. At small radii, the optical depth is large, and the radiation is reprocessed through Comptonization into a narrow, strongly peaked, component. At larger distances the optical depth becomes small and radiation escapes the jet with a non-thermal distribution. The obtained spectra typically peak around $\approx 300$keV (as observed) and with spectral indices below and above the peak that are, for a broad range of the model parameters, close to the observed values. The small radius of dissipation causes the emission to become self absorbed at a few keV and can sufficiently suppress the optical and X-ray fluxes within the limits required by observations (Beniamini & Piran 2014).
Structured surveys of Australian native possum excreta predict Buruli ulcer occurrence in humans

Buruli ulcer (BU) is a neglected tropical disease caused by infection of subcutaneous tissue with Mycobacterium ulcerans. BU is commonly reported across rural regions of Central and West Africa but has been increasing dramatically in temperate southeast Australia around the major metropolitan city of Melbourne. Previous research has shown that Australian native possums are reservoirs of M. ulcerans and that they shed the bacteria in their fecal material (excreta). Field surveys show that locales where possums harbor M. ulcerans overlap with human cases of BU, raising the possibility of using possum excreta surveys to predict the risk of disease occurrence in humans. We thus established a highly structured 12-month possum excreta surveillance program across an area of 350 km2 in the Mornington Peninsula area 70 km south of Melbourne, Australia. The primary objective of our study was to assess if M. ulcerans surveillance of possum excreta provided useful information for predicting future human BU case locations. Over two sampling campaigns in summer and winter, we collected 2282 possum excreta specimens of which 11% were PCR positive for M. ulcerans-specific DNA. Using the spatial scanning statistical tool SatScan, we observed non-random, co-correlated clustering of both M. ulcerans positive possum excreta and human BU cases. We next trained a statistical model with the Mornington Peninsula excreta survey data to predict the future likelihood of human BU cases occurring in the region. By observing where human BU cases subsequently occurred, we show that the excreta model performance was superior to a null model trained using the previous year’s human BU case incidence data (AUC 0.66 vs 0.55). We then used data unseen by the excreta-informed model from a new survey of 661 possum excreta specimens in Geelong, a geographically separate BU endemic area to the southwest of Melbourne, to prospectively predict the location of human BU cases in that region. As for the Mornington Peninsula, the excreta-based BU prediction model outperformed the null model (AUC 0.75 vs 0.50) and pinpointed specific locations in Geelong where interventions could be deployed to interrupt disease spread. This study highlights the One Health nature of BU by confirming a quantitative relationship between possum excreta shedding of M. ulcerans and humans developing BU. The excreta survey-informed modeling we have described will be a powerful tool for efficient targeting of public health responses to stop BU.
Beyond the wave function at the origin: Some momentum-dependent effects in the nonrelativistic quark model

Although the u, d, and s quarks of nonrelativistic potential models are moving at high speeds, the approximation p/mapprox. =0 is used not only in spectroscopy (where its effects may be hidden), but also in calculating transition amplitudes. We have considered a simple scheme for going beyond the static approximation and found that many discrepancies disappear, including those for g/sub A//g/sub V/ and .
Discovery of oxygen in the PG 1159 degenerate stars - A direct evolutionary link to O VI planetary nebula nuclei and confirmation of pulsation theory

The discovery of strong O VI absorption/emission lines in five members of the PG 1159 degenerate stars is reported. It is shown that the optical spectra are dominated by C IV, O VI, and He II, with no detectable N lines. It is confirmed that the planetary nebula-central star, K1-16, which is found to be a pulsating star by Grauer and Bond (1984), is a member of the spectroscopic group. The detection of strong oxygen features in the photospheres of the objects provides support of the prediction of Starrfield et al. (1984). The properties of the PG 1159 stars are compared with the so-called O VI central stars of planetary nebulae and both groups of stars are found to have similar spectral features, temperatures, and luminosities. The implications of the O VI/PG 1159 evolutionary link are assessed.
Exploratory X-Ray Monitoring of Luminous Radio-quiet Quasars at High Redshift: No Evidence for Evolution in X-Ray Variability

We report on the second installment of an X-ray monitoring project of seven luminous radio-quiet quasars (RQQs). New Chandra observations of four of these, at 4.10 ≤ z ≤ 4.35 , yield a total of six X-ray epochs per source, with temporal baselines of ∼ 850 – 1600 days in the rest frame. These data provide the best X-ray light curves for RQQs at z > 4 to date, enabling qualitative investigations of the X-ray variability behavior of such sources for the first time. On average, these sources follow the trend of decreasing variability amplitude with increasing luminosity, and there is no evidence for X-ray variability increasing toward higher redshifts, in contrast with earlier predictions of potential evolutionary scenarios. An ensemble variability structure function reveals that their variability level remains relatively flat across ≈ 20 – 1000 days in the rest frame and it is generally lower than that of three similarly luminous RQQs at 1.33 ≤ z ≤ 2.74 over the same temporal range. We discuss possible explanations for the increased variability of the lower-redshift subsample and, in particular, whether higher accretion rates play a leading role. Near-simultaneous optical monitoring of the sources at 4.10 ≤ z ≤ 4.35 indicates that none is variable on ≈ 1 day timescales, although flux variations of up to ∼25% are observed on ≈ 100 day timescales, typical of RQQs at similar redshifts. Significant optical-X-ray spectral slope variations observed in two of these sources are consistent with the levels observed in luminous RQQs and are dominated by X-ray variations.
Thermal transport investigation in a CNTs/solid matrix composite

The evolution of the thermal parameters of solid-solid composites based on carbon nanotubes (CNTs) (single-walled (SWNT) and multi-walled (MWNT)) were studied. A granular potassium bromide (KBr) material was chosen as a matrix. The evolutions of the dynamic thermal parameters (diffusivity, effusivity and conductivity) of the composites as a function of the weight fraction of the CNTs inclusions were obtained using the photoacoustic technique. The experimental evolution of the thermal conductivity of the composites with the CNTs loading showed two distinct behaviours, an increase up to around 2% of CNTs loading followed by a decrease. A heat transport model has been proposed to account for these two different observed trends providing a consistent explanation of the experimental data.
Universality and anisotropy in passive scalar fluctuations in turbulence with uniform mean gradient

Passive scalar and velocity fluctuations in homogeneous isotropic turbulence with or without mean scalar gradient are studied by using high-resolution direct numerical simulation (DNS). The local scaling exponents of the velocity structure functions are newly computed at larger Reynolds number, and the values at their plateau in the inertial range are found to be consistent with the previous DNS and experimental data. The 4/3 law for the velocity–scalar mixed correlation and the high-order structure functions of the passive scalar increment are analyzed in terms of the Legendre polynomial expansion. It is shown theoretically that the contributions from the second order in the expansion can be removed by taking the average over three directions parallel and perpendicular to the mean gradient, and it is found numerically that the contributions higher than the fourth order are negligible. The scaling exponents of the isotropic part of the scalar structure functions under the mean gradient are found to have the well-developed scaling range and are smaller than those in the isotropic case. The different behavior in the local scaling exponents with or without the mean gradient is examined and the universality of the scaling exponents is discussed.
The Ages of M31 Star Clusters: Spectral Energy Distribution versus Color–Magnitude Diagram

It is well-known that fitting Color–Magnitude Diagrams (CMDs) to theoretical isochrones is the main method to determine star cluster ages. However, when CMDs are not available, the Spectral Energy Distribution (SED)-fitting technique is the only other approach, although it suffers the age–metallicity–reddening degeneracy. In this work, we gather the ages, metallicities, and masses of dozens of M31 star clusters from the CMD-fitting with Hubble Space Telescope images from the literature for comparison. We check the reliability of the SED-fitting results with different models, i.e., Bruzual & Charlot model (BC03), Galaxy Evolutionary Synthesis Models (GALEV), and Advanced Stellar Population Synthesis (ASPS) for the simple stellar populations (SSPs) with single stars (ss)-SSP/binary-star (bs)-SSPs models. The photometry bands includes the Galaxy Evolution Explorer GALEX FUV/NUV bands, optical/near-infrared UBVRIJHK bands, as well as the Wide-field Infrared Survey Explorer (WISE) W1/W2 bands. The comparisons show that the SED-fitting ages agree well with the CMD-fitting ages, either with the fixed metallicity or with the free metallicity for both the BC03 and the GALEV model. However, for the ASPS models, it seems that SED-fitting results are systematically older than the CMD ages, especially for the ages log t < 9.0 (year). The fitting also shows that the GALEX FUV/NUV-band are more important than the WISE W1/W2 for constraining the ages, which confirms the previous findings. We also derived the masses of our sample star clusters from the BC03 and GALEV models and it is found that the values agree well with those in the literature.
An introduction to the measurement of auditory event-related potentials (ERPs)

: In 1939, Pauline Davis reported the ﬁrst study on event-related potentials (ERPs) performed on awake humans. ERPs are time-locked brain potentials that occur in response to cognitive, motor or perceptual events . The events used by Davis were sounds, and in the decades that followed her landmark study ERP research signiﬁcantly contributed to the knowledge of auditory perception and neurophysiology we have today. ERPs are very well suited to study neural responses to sound stimuli, since the researcher can monitor the brain’s registration of sound edges and spectral changes in sound on a millisecond-by-millisecond basis. In this overview we will introduce basic concepts of auditory ERP research. The overview includes descriptions of typical ERP components, experimental paradigms, sound stimuli, research methodology, and ways to analyze data.
Early X-Ray/Ultraviolet Line Signatures of Gamma-Ray Burst Progenitors and Hypernovae

We calculate the X-ray/UV spectral line signatures expected from the interaction of a gamma-ray burst afterglow and a dense preburst environment produced by the progenitor. We explore the conditions under which Fe line and edge equivalent widths of ~1 keV can arise, and discuss the possibility of gaining information about possible progenitor scenarios using X-ray metal-line spectra in the first few days of a burst. A wind or supernova shell around the burst produces an X-ray absorption line spectrum and later emission lines, while a hypernova funnel model produces mainly emission lines. The Fe K-edge can in some cases be more prominent than the Fe Kα line. Under simple assumptions for the input continuum luminosity, current reports of observed Fe line luminosities are compatible with an Fe-enriched funnel model, while lower values are expected in shell models.
Numerical computation of constant mean curvature surfaces using finite elements

This paper presents a method for computing two-dimensional constant mean curvature surfaces. The method in question uses the variational aspect of the problem to implement an efficient algorithm. In principle, it is a flow-like method in that it is linked to the gradient flow for the area functional, which gives reliable convergence properties. In the background, a preconditioned conjugate gradient method works, which gives the speed of a direct elliptic multigrid method.
Interplay of Disorder and Spin Fluctuations in the Resistivity near a Quantum Critical Point

The resistivity in metals near an antiferromagnetic quantum critical point (QCP) is strongly affected by small amounts of disorder. In a quasi-classical treatment, we show that an interplay of strongly anisotropic scattering due to spin fluctuations and isotropic impurity scattering leads to a large regime where the resistivity varies as T^alpha, with an anomalous exponent, alpha, 1 <= alpha <= 1.5, depending on the amount of disorder. I argue that this mechanism explains in some detail the anomalous temperature dependence of the resistivity observed in CePd_2Si_2, CeNi_2Ge_2 and CeIn_3 near the QCP.
An inequality satisfied by the Gamma function

Abstract 1. Summary For all real values of α and λ satisfying α + λ > 0, α ≠ 0, α ≠ 1, λ > 0 the following inequality involving the Gamma function holds: This follows from a general inequality for the variance of regular unbiased estimators given by Cramer [1].
A spin metal–oxide–semiconductor field-effect transistor using half-metallic-ferromagnet contacts for the source and drain

We propose and theoretically analyze a metal–oxide–semiconductor field-effect-transistor (MOSFET) type of spin transistor (spin MOSFET) consisting of a MOS structure and half-metallic-ferromagnet (HMF) contacts for the source and drain. When the magnetization configuration of the HMF source and drain is parallel (antiparallel), highly spin-polarized carriers injected from the HMF source to the channel are transported into (blocked by) the HMF drain, resulting in the magnetization-configuration-dependent output characteristics. Our two-dimensional numerical analysis indicates that the spin MOSFET exhibits high (low) current drive capability in the parallel (antiparallel) magnetization, and that extremely large magnetocurrent ratios can be obtained. Furthermore, the spin MOSFET satisfies other important requirements for “spintronic integrated circuits,” such as high amplification capability, low power-delay product, and low off-current.
Hybrid Beamforming Design for Self-Interference Cancellation in Full-Duplex Millimeter-Wave MIMO Systems with Dynamic Subarrays

Full-duplex (FD) millimeter-wave (mmWave) multiple-input multiple-output (MIMO) communication is a promising solution for the extremely high-throughput requirements in future cellular systems. The hybrid beamforming structure is preferable for its low hardware complexity and low power consumption with acceptable performance. In this paper, we introduce the hardware efficient dynamic subarrays to the FD mmWave MIMO systems and propose an effective hybrid beamforming design to cancel the self-interference (SI) in the considered system. First, assuming no SI, we obtain the optimal fully digital beamformers and combiners via the singular value decomposition of the uplink and downlink channels and the water-filling power allocation. Then, based on the obtained fully digital solutions, we get the dynamic analog solutions and digital solutions using the Kuhn–Munkres algorithm-aided dynamic hybrid beamforming design. Finally, we resort to the null space projection method to cancel the SI by projecting the obtained digital beamformer at the base station onto the null space of the equivalent SI channel. We further analyze the computational complexity of the proposed method. Numerical results demonstrate the superiority of the FD mmWave MIMO systems with the dynamic subarrays using the proposed method compared to the systems with the fixed subarrays and the half-duplex mmWave communications. When the number of RF chains is 6 and the signal-to-noise ratio is 10 dB, the proposed design outperforms the FD mmWave MIMO systems with fixed subarrays and the half-duplex mmWave communications, respectively, by 22.4% and 47.9% in spectral efficiency and 19.9% and 101% in energy efficiency.
Copula models in machine learning

The introduction of copulas, which allow separating the dependence structure of a multivariate distribution from its marginal behaviour, was a major advance in dependence modelling. Copulas brought new theoretical insights to the concept of dependence and enabled the construction of a variety of new multivariate distributions. Despite their popularity in statistics and financial modelling, copulas have remained largely unknown in the machine learning community until recently. This thesis investigates the use of copula models, in particular Gaussian copulas, for solving various machine learning problems and makes contributions in the domains of dependence detection between datasets, compression based on side information, and variable selection. Our first contribution is the introduction of a copula mixture model to perform dependency-seeking clustering for co-occurring samples from different data sources. The model takes advantage of the great flexibility offered by the copula framework to extend mixtures of Canonical Correlation Analyzers to multivariate data with arbitrary continuous marginal densities. We formulate our model as a non-parametric Bayesian mixture and provide an efficient Markov Chain Monte Carlo inference algorithm for it. Experiments on real and synthetic data demonstrate that the increased flexibility of the copula mixture significantly improves the quality of the clustering and the interpretability of the results. The second contribution is a reformulation of the information bottleneck (IB) problem in terms of a copula, using the equivalence between mutual information and negative copula entropy. Focusing on the Gaussian copula, we extend the analytical IB solution available for the multivariate Gaussian case to meta-Gaussian distributions which retain a Gaussian dependence structure but allow arbitrary marginal densities. The resulting approach extends the range of applicability of IB to non-Gaussian continuous data and is less sensitive to outliers than the original IB formulation. Our third and final contribution is the development of a novel sparse compression technique based on the information bottleneck (IB) principle, which takes into account side information. We achieve this by introducing a sparse variant of IB that compresses the data by preserving the information in only a few selected input dimensions. By assuming a Gaussian copula we can capture arbitrary non-Gaussian marginals, continuous or discrete. We use our model to select a subset of biomarkers relevant to the evolution of malignant melanoma and show that our sparse selection provides reliable predictors.
Hydrophilic Natural Polylysine as Drug Nanocarrier for Preparation of Helical Delivery System

Polypeptide materials have clear secondary structure and biodegradability, which can be further modified and functionalized, so that they can be employed as therapeutic agents in clinical applications. PEGylation of polylysine (PEG-PLL) is a kind of safe and effective nanocarrier that is utilized for gene and drug delivery. However, PEG-PLL needs to be produced through chemical synthesis, which is expensive and difficult to obtain. We hope to simplify the nanocarrier and use hydrophilic natural polylysine (PLL) to develop a high-efficacy delivery system. To evaluate the possibility of PLL as nanocarriers, methotrexate (MTX) is selected as a model drug and PEG-PLL is utilized as control nanocarriers. The experimental results showed that PLL is an ideal polypeptide to prepare MTX-loaded PLL nanoparticles (PLL/MTX NPs). Compared with PEG-PLL as nanocarriers, PLL/MTX NPs showed higher drug-loading content (58.9%) and smaller particle sizes (113.7 nm). Moreover, the shape of PLL/MTX NPs was a unique helical nanorod. The PLL/MTX NPs had good storage stability, media stability, and sustained release effect. Animal research demonstrated that PLL/MTX NPs could improve the anti-tumor activity of MTX, the antitumor efficacy is enhanced 1.9-fold and 1.2-fold compared with MTX injection and PEG-PLL/MTX NPs, respectively. To sum up, natural polymer PLL is an ideal nano drug delivery carrier which has potential clinical applications.
Physiological response of a wild rodent to experimental manipulations in its natural environment using infrared thermography

Heatlossfromnon-insulating bodypartsofrodentscanbeused asaproxytoStress-InducedHyper- thermia (SIH) and can be detected via non-invasive methods, such as infrared thermography (IRT). Although IRT has been systematically used to detect SIH in captive or laboratory animals, very few studies have been performed in wild situations. We investigated the SIH in a wild rodent, the Eastern Broad-toothed Field Mouse Apodemus mystacinus , faced with novel stressors in its natural habitat, using IRT. We subjected live-trapped individuals to six consecutive experimental manipulations (Experimental Manipulations Phase - EMP), and then we temporarily transferred them to a wooden box to partly overcome the stressful challenges (Transitory Release Phase - TRP). We used the maximum eye temperature diﬀerence between the start of the EMP and the start of the TRP ( ∆ T SIH ) as the best estimate of SIH. Mean eye temperature during EMP diﬀered signiﬁcantly from that of TRP for each individual and the diﬀerences were similar when examined separately as to sex, trapping history, or breeding condition. Comparison of eye temperature time series for diﬀerent trapping history groups showed a higher similarity of the response of ﬁrst captures with 2 nd and 3 rd recaptures than of ﬁrst captures with 1 st recaptures, veriﬁed by a comparison of ∆ T SIH for these groups. Larger-sized ﬁrst-captured individuals appeared less stressed by the experimental procedure than smaller-sized individuals. Overall, IRT appears to be a useful and feasible method for non-invasive monitoring of SIH.