Miracle-dz/UniFAR-FTUs huggingface dataset:
Theoretical investigation of the quantum noise in ghost imaging

Ghost imaging is a method to nonlocally image an object by transmitting pairs of entangled photons through the object and a reference optical system respectively. We present a theoretical analysis of the quantum noise in this imaging technique. The dependence of the noise on the properties of the apertures in the imaging system are discussed and demonstrated with a numerical example. For a given source, the resolution and the signal-to-noise ratio cannot be improved at the same time .
Frustrated Kondo chains and glassy magnetic phases on the pyrochlore lattice

We present an extensive numerical study of a new type of frustrated itinerant magnetism on the pyrochlore lattice. In this picture, the pyrochlore magnet can be viewed as a cross-linking network of Kondo or double-exchange chains. Contrary to models based on Mott insulators, this itinerant magnetism approach provides a natural explanation for several spin and orbital superstructures observed on the pyrochlore lattice. Through extensive Monte Carlo simulations, we obtain the phase diagrams at two representative electron filling fractions $n = 1/2$ and 2/3. In particular, we show that an intriguing glassy magnetic state characterized by ordering wavevectors $\mathbf q = \langle \frac{1}{3},\frac{1}{3}, 1\rangle$ gives a rather satisfactory description of the low temperature phase recently observed in spinel GeFe$_2$O$_4$.
Influence of discharge polarity on streamer breakdown criterion of ambient air in a non-uniform electric field

Streamer breakdown of atmospheric air with non-uniform dc electric field in a needle-to-plate electrode configuration is studied using a semi-analytic model and experimental measurements. A high voltage (either positive or negative) is applied to a hollow needle with 0.51mm outer diameter and 0.25mm inner diameter separated from a planar ground electrode by a gap distance of 0.1–1.4 cm. Breakdown voltages are recorded for both positive and negative discharge polarities. Empirical relations between the critical avalanche size for streamer breakdown and the gap distance are proposed. Using these empirical relations, a semi-analytic model based on Meek’s criterion for streamer breakdown is developed to accurately predict the measured breakdown voltages. It is found that for 380{\text{ Torr }}\;{\text{cm}}$? > pd>380 Torr cm (or d $? > > 0.5 cm at one atmosphere) streamer breakdown of ambient air occurs at a lower applied voltage for a positively biased needle compared to that with a negatively biased needle, referred as the polarity effect. For pd<380 Torr cm breakdown is attained at a lower applied voltage with a negatively biased needle compared to that with a positively biased needle, and breakdown mode transits from the polarity effect to the so called inverted polarity effect.
READING SKILLS FORMATION: CRITICAL ANALYSIS OF THE IELTS MATERIALS

In this article, we focus on the description and analysis of the IELTS material used for preparation and testing reading receptive communication skills. Two IELTS test formats, General Training and Academic are studied. This research studies educational materials and evaluates them by the scheme described above by means of comparative analysis. The findings are presented in two parts, in descriptive and quantitative forms. The descriptive part presents the topics of the texts, forms of narration, and sentence structures. The morphological word structures and vocabulary of the texts and exercises and/or test tasks are compared. Since the key words in the questions to the texts of the reading section are paraphrased, the authors analyzed these questions and texts using the approach that comprises the personal elements if it is challenging or not. The quantitative part includes the number of questions that refer to vocabulary and grammar, namely, to morphological and syntactic characteristics of speech in each section of the Reading Module. The usage of specific British, American, Canadian, Australian, New Zealand expressions and facts in the texts as evidence of differences in their cultures is described. The result of the analysis is classified and analyzed according to quantitative and qualitative characteristics.
Impulsive phase Fe K-alpha emission in a flare of 1989 March

Evidence for enhanced Fe K-alpha line emission that is coincident (to within 15 s) of an intense hard X-ray (greater than 50 keV) burst is presented on the basis of observations of the Fe K-alpha soft X-ray line made with the SMM. Three different models for explaining the K-alpha enhancement are investigated, namely, photoexcitation by soft X-ray thermal bremsstrahlung radiation from an isothermal source, collisional excitation by nonthermal thick-target electrons, and photoexcitation by a nonthermal hard X-ray flux distribution which extends with a power-law spectrum down to the Fe K-alpha ionization threshold at 7.1 keV. It is found that, to within the limits of isothermal temperature and emission measure set by soft X-ray observations, the thermal photoexcitation model cannot reproduce satisfactorily the intensity of enhanced K-alpha emission during the hard X-ray impulsive phase. The impulsive phase K-alpha flux exceeds that predicted by the thermal photoexcitation model by about 3 sigma. The implications of these results for the nonthermal interpretation of impulsive hard X-ray bursts in solar flares are discussed.
A new bound on axion-like particles

Axion-like particles (ALPs) and photons can quantum mechanically interconvert when propagating through magnetic fields, and ALP-photon conversion may induce oscillatory features in the spectra of astrophysical sources. We use deep (370 ks), short frame time Chandra observations of the bright nucleus at the centre of the radio galaxy M87 in the Virgo cluster to search for signatures of light ALPs. The absence of substantial irregularities in the X-ray power-law spectrum leads to a new upper limit on the photon-ALP coupling, gaγ: using a very conservative model of the cluster magnetic field consistent with Faraday rotation measurements from M87 and M84, we find g_{a\gamma} < 2.6 \times 10^{-12} {\rm GeV}^{-1} at 95% confidence level for ALP masses ma ⩽ 10−13 eV. Other consistent magnetic field models lead to stronger limits of gaγ ≲ 1.1–1.5 × 10−12 GeV−1. These bounds are all stronger than the limit inferred from the absence of a gamma-ray burst from SN1987A, and rule out a substantial fraction of the parameter space accessible to future experiments such as ALPS-II and IAXO.
Fracton pairing mechanism for unconventional superconductors: Self-assembling organic polymers and copper-oxide compounds

Self-assembling organic polymers and copper-oxide compounds are two classes of unconventional superconductors, whose challenging behavior does not comply with the traditional picture of Bardeen-Cooper-Schrieffer (BCS) superconductivity in regular crystals. In this paper, we propose a theoretical model that accounts for the basic superconducting properties of either class of the unconventional materials. These properties are considered as interconnected manifestations of the same phenomenon: We argue that superconductivity occurs in both cases because the charge carriers (i.e., electrons or holes) exchange fracton excitations, quantum oscillations of fractal lattices that mimic the complex microscopic organization of the unconventional superconductors. For the copper oxides, the superconducting transition temperature ${T}_{c}$ as predicted by the fracton mechanism is of the order of $\ensuremath{\sim}150 \mathrm{K}. $ We suggest that the marginal ingredient of the high-temperature superconducting phase is provided by fracton coupled holes that condensate in the conducting copper-oxygen planes owing to the intrinsic field-effect-transistor configuration of the cuprate compounds. For the gate-induced superconducting phase in the electron-doped polymers, we simultaneously find a rather modest transition temperature of $\ensuremath{\sim}2\char21{}3 \mathrm{K}$ owing to the limitations imposed by the electron tunneling processes on a fractal geometry. We speculate that the hole-type superconductivity shows a larger onset temperature when compared to its electron-type counterpart. This promises an intriguing possibility of high-temperature superconducting states in hole-doped complex materials. The theoretical methods applied in our study bring together the so-called strange (or fractional) dynamics and the unconventional, topological description of the complex fractal sets underlying the fracton spectrum. A generalized kinetic equation containing integer time and fractional real-space derivatives is found for the fracton excitations in the harmonic approximation. The fracton superconductivity mechanism is further discussed in connection with experimental observations. An important prediction of the present study is the universality of ac conduction of the unconventional materials above the superconducting transition temperature ${T}_{c}. $
Pharmacogenetic Testing of Cytochrome P450 System Enzymes in the Therapy of Bipolar Affective Disorder

Bipolar affective disorder (BPS) is a common and socially significant mental disorder that requires long-term use of psychotropic drugs (PDs). Long-term use of PDs increases the risk of developing adverse drug reactions (ADRs) and/or therapeutic resistance in some patients. This may be due to a genetically determined impairment of PDs metabolism by cytochrome P450 enzymes. Pharmacogenetic testing (PGx) is a method to identify a group of patients with a high risk of developing PDs -induced ADRs. Our experience of using PGx to search for low-functional and non-functional single nucleotide variants (SNVs) / polymorphisms of the CYP1A2, CYP2C8, CYP3A4, CYP3A5 and CYP2D6 genes encoding cytochrome P450 enzymes involved in PDs metabolism demonstrates the importance of this new personalized approach to the choice of PDs and its dosing in patients with pharmacogenetic profile poor metabolizer. The main purpose of the case report is to present the experience of using PGx in the therapy of dipolar affective disorder.
The Bestvina–Brady Construction Revisited: Geometric Computation of ∑‐Invariants for Right‐Angled Artin Groups

The starting point of our investigation is the remarkable paper [2] in which Bestvina and Brady gave an example of an infinitely related group of type FP2. The result about right‐angled Artin groups behind their example is best interpreted by means of the Bieri–Strebel–Neumann–Renz Σ‐invariants.
Efficiency Analysis of Syrian Refugees’ Healthcare Services in Turkey and Other 3RP States

Access to healthcare for refugees is often contextually and conceptually diverse. This study set out to evaluate the efficiency of the healthcare services provided for Syrian refugees in Turkey and other refugee response and resilience plan (3RP) states. Data envelopment analysis is utilized for efficiency analysis using primary healthcare system indicators. Efficiency is broken down into pure technical efficiency and scale efficiency to identify causes of inefficiency. Normative analysis is used to employ a teleological approach to better understand current refugee healthcare policies. The findings show a decline in the overall efficiency for Turkey and other 3RP states. However, Turkey’s operational practices could be a model for other 3RP states due to its relatively high pure technical efficiency. Scale inefficiency negatively impacts the overall efficiency of Turkey’s service, while other 3RP states exhibit a rather consistent performance. The study concludes that Turkey’s healthcare system for refugees is inefficient, resulting in inadequate access for Syrian refugees. As such, operational and scale efficiency must be synergized for Turkey to fulfill its obligation to provide adequate healthcare for Syrian refugees. Additionally, COVID-19 was found to have exacerbated the challenges Syrian refugees face accessing healthcare. Policy recommendations have been made in line with the findings of the study.
Accurate Ray-tracing of Realistic Neutron Star Atmospheres for Constraining Their Parameters

Thermal-dominated X-ray spectra of neutron stars in quiescent, transient X-ray binaries and neutron stars that undergo thermonuclear bursts are sensitive to mass and radius. The mass–radius relation of neutron stars depends on the equation of state (EoS) that governs their interior. Constraining this relation accurately is therefore of fundamental importance to understand the nature of dense matter. In this context, we introduce a pipeline to calculate realistic model spectra of rotating neutron stars with hydrogen and helium atmospheres. An arbitrarily fast-rotating neutron star with a given EoS generates the spacetime in which the atmosphere emits radiation. We use the Lorene/nrotstar code to compute the spacetime numerically and the Atm24 code to solve the radiative transfer equations self-consistently. Emerging specific intensity spectra are then ray-traced through the neutron star’s spacetime from the atmosphere to a distant observer with the Gyoto code. Here, we present and test our fully relativistic numerical pipeline. To discuss and illustrate the importance of realistic atmosphere models, we compare our model spectra to simpler models like the commonly used isotropic color-corrected blackbody emission. We highlight the importance of considering realistic model-atmosphere spectra together with relativistic ray-tracing to obtain accurate predictions. We also insist upon the crucial impact of the star’s rotation on the observables. Finally, we close a controversy that has been ongoing in the literature in the recent years, regarding the validity of the Atm24 code.
A Distributionally Robust Defender-Attacker-Defender Model for Resilience Enhancement of Power Systems Against Malicious Cyberattacks

The cybersecurity of electric power grids is emerging as a critical challenge for the power industry in the transformation of modern power systems towards the future smart grid. It is of great importance to enhance the resilience of power systems against potential cyber threats. In this paper, a distributionally robust recovery resource allocation method based on the tri-level defender-attacker-defender (D-A-D) model is proposed to enhance the resilience of power systems in the face of malicious cyberattacks. The proposed recovery resource allocation method is able to optimally distribute the recovery resources among the substations in the grid to mitigate the impacts of successful cyberattacks during the recovery process, and improve the resilience performance of power systems against the attacks. In the proposed model, the recovery resource represents the available resource that can be expended to support the recovery efforts of the cyber-physical power system. It is expected to accelerate the recovery process of the system after successful attacks. The recovery resource may include necessary software, hardware, and labor force. Meanwhile, a distributionally robust optimization (DRO) model is proposed to address the uncertainty of the power system operation conditions, e.g., renewable energy resources (RESs). In order to verify the proposed system defense method, case studies were conducted on the IEEE Reliability Test System RTS-79. The results of the case studies show that the proposed method can provide a robust solution to recovery resource allocation for mitigating the risk of potential cyberattacks.
Something about the structure of the Galaxy

ABSTRA C T We analyse a sample of 507 evolved (OH/IR) stars in the region O10 8. ‘ . 2 458U; Ojbj , 38U. We derive average ages for subsets of this sample, and use those sets as beacons for the evolution of the Galaxy. In the bulge, the oldest OH/IR stars in the plane are 7.5 Gyr (1.3 M(), and in the disc 2.7 Gyr (2.3 M(). The vertical distribution of almost all AGB stars in the disc is found to be nearly exponential, with scaleheight increasing from 100 pc for stars &1 Gyr old to 500 pc for stars *5 Gyr old. There may be a small, disjunct population of OH/IR stars. The radial distribution of AGB stars is dictated by the metallicity gradient. Unequivocal morphological evidence is presented for the existence of a central bar, but parameters can be constrained only for a given spatial-density model. Using a variety of indicators, we identify the radii of the inner ultraharmonic (2.5 kpc) and corotation resonance (3.5 kpc). We show that the 3-kpc arm is likely to be an inner ring, as observed in other barred galaxies, by identifying a group of evolved stars that is connected to the 3-kpc H i filament. Also, using several observed features, we argue that an inner-Lindblad resonance exists, at ,1‐1:5 kpc. The compositions of OH/IR populations within 1 kpc of the Galactic Centre give insight into the bar-driven evolution of the inner regions. We suggest that the bar is ,8 Gyr old, relatively weak (SAB), and may be in a final stage of its existence.
Patient-Specific Cerebral Aneurysm Hemodynamics: Comparison of in vitro Volumetric Particle Velocimetry, Computational Fluid Dynamics (CFD), and in vivo 4D Flow MRI

Typical approaches to patient-specific hemodynamic studies of cerebral aneurysms use image based computational fluid dynamics (CFD) and seek to statistically correlate parameters such as wall shear stress (WSS) and oscillatory shear index (OSI) to risk of growth and rupture. However, such studies have reported contradictory results, emphasizing the need for in-depth comparisons of volumetric experiments and CFD. In this work, we conducted tomographic particle velocimetry experiments using two patient-specific cerebral aneurysm models (basilar tip and internal carotid artery) under pulsatile flow conditions and processed the particle images using Shake the Box (STB), a particle tracking method. The STB data was compared to that obtained from in vivo 4D flow MRI and CFD. Although qualitative agreement of flow pathlines across modalities was observed, each modality maintained notably unique spatiotemporal distributions of low normalized WSS regions. Analysis of time averaged WSS (TAWSS), OSI, and Relative Residence Time (RRT) demonstrated that non-dimensional parameters, such as OSI, may be more robust to the varying assumptions, limitations, and spatial resolutions of each subject and modality. These results suggest a need for further multi-modality analysis as well as development of non-dimensional hemodynamic parameters and correlation of such metrics to aneurysm risk of growth and rupture.
Sensitivity Region-Based Optimization for Maximizing Renewable Generation Hosting Capacity of an Islanded Microgrid

Renewable energy based distributed generators are key components in islanded microgrids. However, their power intermittency and uncertainty may impair power quality and cause system operating constraint violations. It is imperative to evaluate and maximize the hosting capacity of an islanded microgrid for renewable generation. Besides, conventional optimization methods focus on improving the solution robustness on constraints under uncertainties but ignoring that on the optimization objective. To address these unsolved issues, a sensitivity region (SR) based optimization method for maximizing renewable generation hosting capacity of an islanded microgrid is proposed. This paper firstly proposes an optimization model considering microgrid frequency variation and microturbine droop control functionality. Secondly, SR and feasibility-SR are adopted to quantify solution robustness against uncertainties of renewable generation and load. It is expected to enlarge these two regions to cover all the possible uncertainty realizations, thus providing robust solutions. Last, this paper develops an SR based optimization method with a new solution algorithm. Through comprehensive numerical simulations, the proposed SR based hosting capacity maximization method is verified with high solution robustness on both objective and operating constraints.
Undersociality is Unwise

Wise decisions are often guided by an accurate understanding of the expected values of different possible choices. In social contexts, wisdom comes from understanding how others are likely to respond to one's actions, enabling people to make choices that maximize both their own and others' outcomes. Our research suggests that miscalibrated social cognition may create a systematic barrier to wiser decisions in social life. From expressing appreciation to offering support to performing acts of kindness, this program of research indicates that decisions to engage with others are driven by how people expect a recipient to respond, but that people consistently underestimate how positively others will respond to their other-oriented actions. Because connecting with others consistently increases people's own wellbeing, miscalibrated social cognition may lead to undersociality : being overly reluctant to reach out and connect with others. Miscalibrated expectations about social engagement can create markets for products that help people overcome these barriers in order to consume their time, money, and effort
Progress and problems in quantum gravity

From the point of view of an uncompromising field theorist quantum gravity is beset with serious technical and, above all, conceptual problems with regard especially to the meaning of genuine "physical" observables. This situation is not really improved by the appearance of recent attempts to reformulate gravity within some novel framework.However, the original aim, a background-independent quantum theory of gravity, can be achieved in a particular area, namely 2d dilaton quantum gravity without any assumptions beyond standard quantum field theory. Some important by-products of the research of the "Vienna School" include the introduction of the concept of Poisson-Sigma models, a verification of the "virtual Black Hole" and the extensions to N = (1,1) and N = (2,2) 2d-supergravity, for which complete solutions of some old problems have been possible which are relevant for superstring theory