Miracle-dz/UniFAR-FTUs huggingface dataset:
The 511 keV emission from positron annihilation in the Galaxy

The first $\ensuremath{\gamma}$-ray line originating from outside the Solar System that was ever detected is the 511 keV emission from positron annihilation in the Galaxy. Despite 30 years of intense theoretical and observational investigation, the main sources of positrons have not been identified up to now. Observations in the 1990s with OSSE/CGRO (Oriented Scintillation Spectrometer Experiment on GRO satellite/Compton Gamma Ray Observatory) showed that the emission is strongly concentrated toward the Galactic bulge. In the 2000s, the spectrometer SPI aboard the European Space Agency's (ESA) International Gamma Ray Astrophysics Laboratory (INTEGRAL) allowed scientists to measure that emission across the entire Galaxy, revealing that the bulge-to-disk luminosity ratio is larger than observed at any other wavelength. This mapping prompted a number of novel explanations, including rather ``exotic'' ones (e.g., dark matter annihilation). However, conventional astrophysical sources, such as type Ia supernovae, microquasars, or x-ray binaries, are still plausible candidates for a large fraction of the observed total 511 keV emission of the bulge. A closer study of the subject reveals new layers of complexity, since positrons may propagate far away from their production sites, making it difficult to infer the underlying source distribution from the observed map of 511 keV emission. However, in contrast to the rather well-understood propagation of high-energy ($g\mathrm{GeV}$) particles of Galactic cosmic rays, understanding the propagation of low-energy ($\ensuremath{\sim}\mathrm{MeV}$) positrons in the turbulent, magnetized interstellar medium still remains a formidable challenge. The spectral and imaging properties of the observed 511 keV emission are reviewed and candidate positron sources and models of positron propagation in the Galaxy are critically discussed.
Magneto-elastic coupling in a potential ferromagnetic 2D atomic crystal

Cr2Ge2Te6 has been of interest for decades, as it is one of only a few naturally forming ferromagnetic semiconductors. Recently, this material has been revisited due to its potential as a two-dimensional semiconducting ferromagnet and a substrate to induce anomalous quantum Hall states in topological insulators. However, many relevant properties of Cr2Ge2Te6 still remain poorly understood, especially the spin-phonon coupling crucial to spintronic, multiferrioc, thermal conductivity, magnetic proximity and the establishment of long range order on the nanoscale. We explore the interplay between the lattice and magnetism through high resolution micro-Raman scattering measurements over the temperature range from 10 to 325 K. Strong spin-phonon coupling effects are confirmed from multiple aspects: two low energy modes splits in the ferromagnetic phase, magnetic quasielastic scattering in the paramagnetic phase, the phonon energies of three modes show clear upturn below TC, and the phonon linewidths change dramatically below TC as well. Our results provide the first demonstration of spin-phonon coupling in a potential two-dimensional atomic crystal.
Molecular Rings in Galaxies and a Possible New Cosmic Distance Indicator

The molecular gas distribution in the nuclear regions of galaxies can be classified into three types : a core (C) type with a high-density peak toward the nucleus; a compact-ring (CR) type with ring radius of ∼200 pc; and a broad-ring (BR) type with ring radius of 750 pc. We discuss the possibility of using the ring radius as a cosmic distance indicator for galaxies up to about 100 Mpc. We stress that this geometrical method is independent of such correction factors as extinction and reddening
Counts of high-redshift GRBs as probes of primordial non-Gaussianities

We propose to use high-redshift long γ-ray bursts (GRBs) as cosmological tools to constrain the amount of primordial non-Gaussianity in the density field. By using numerical, N-body, hydrodynamic, chemistry simulations of different cosmological volumes with various Gaussian and non-Gaussian models, we self-consistently relate the cosmic star formation rate density to the corresponding GRB rate. Assuming that GRBs are fair tracers of cosmic star formation, we find that positive local non-Gaussianities, described in terms of the non-linear parameter, fNL, might boost significantly the GRB rate at high redshift, z ≫ 6. Deviations with respect to the Gaussian case account for a few orders of magnitude if fNL ∼ 1000, one order of magnitude for fNL ∼ 100 and a factor of ∼2 for fNL ∼ 50. These differences are found only at large redshift, while at later times the rates tend to converge. Furthermore, a comparison between our predictions and the observed GRB data at z > 6 allows us to exclude large negative fNL, consistently with previous works. Future detections of any long GRB at extremely high redshift (z ∼ 15–20) could favour non-Gaussian scenarios with positive fNL. More stringent constraints require much larger high-z GRB complete samples, currently not available in the literature. By distinguishing the contributions to the GRB rate from the metal-poor Population III regime, and the metal-enriched Population II–I regime, we conclude that the latter is a more solid tracer of the underlying matter distribution, while the former is strongly dominated by feedback mechanisms from the first, massive, short-lived stars, rather than by possible non-Gaussian fluctuations. This holds quite independently of the assumed Population III initial mass function.
Elastic Coulomb-levitation: why is ice so slippery?

The elastic, less dense, polarized, and thermally stable supersolid skin lubricates ice. Molecular undercoordination shortens the H-O bond and lengthens the O:H nonbond through O-O repulsion, which is associated with low-frequency and high-magnitude of O:H vibration and a dual O-O polarization. The softer O:H springs attached with stronger molecular dipoles provide forces levitating objects sliding on ice, like Maglev or Hovercraft.
Type Ia Supernova Intrinsic Magnitude Dispersion and the Fitting of Cosmological Parameters

I present an analysis for fitting cosmological parameters from a Hubble diagram of a standard candle with unknown intrinsic magnitude dispersion. The dispersion is determined from the data, simultaneously with the cosmological parameters. This contrasts with the strategies used to date. The advantages of the presented analysis are that it is done in a single fit (it is not iterative), it provides a statistically founded and unbiased estimate of the intrinsic dispersion, and its cosmological-parameter uncertainties account for the intrinsic-dispersion uncertainty. Applied to Type Ia supernovae, my strategy provides a statistical measure to test for subtypes and assess the significance of any magnitude corrections applied to the calibrated candle. Parameter bias and differences between likelihood distributions produced by the presented and currently used fitters are negligibly small for existing and projected supernova data sets.
Thermal properties of graphene: Fundamentals and applications

Graphene is a two-dimensional (2D) material with over 100-fold anisotropy of heat flow between the in-plane and out-of-plane directions. High in-plane thermal conductivity is due to covalent sp ^2 bonding between carbon atoms, whereas out-of-plane heat flow is limited by weak van der Waals coupling. Herein, we review the thermal properties of graphene, including its specific heat and thermal conductivity (from diffusive to ballistic limits) and the influence of substrates, defects, and other atomic modifications. We also highlight practical applications in which the thermal properties of graphene play a role. For instance, graphene transistors and interconnects benefit from the high in-plane thermal conductivity, up to a certain channel length. However, weak thermal coupling with substrates implies that interfaces and contacts remain significant dissipation bottlenecks. Heat flow in graphene or graphene composites could also be tunable through a variety of means, including phonon scattering by substrates, edges, or interfaces. Ultimately, the unusual thermal properties of graphene stem from its 2D nature, forming a rich playground for new discoveries of heat-flow physics and potentially leading to novel thermal management applications.
A Secure k -nearest Neighbor Query Processing Method Based on Extended Range of Cipher-Text Search

To improve the effect of privacy protection and the query service quality in a cloud environment, a secure k -nearest neighbor (kNN) query processing method based on an extended range of cipher-text search is proposed. Firstly, the area is divided into several square grids, and the Morton code of each location is calculated. Then, the location data is encrypted using public-key encryption and scrambling encryption, which is outsourced to the cloud server. When querying kNN interest points, a query request is sent to the data owner by the user. After obtaining the query trapdoor and private key, the query trapdoor is sent to the cloud server for the query. On the server-side, the grid region of the current location is found according to the approximate matching between the Morton codes. The current grid is used as the center to expand the search area until kNN interest points are found and sent to the querying user. Finally, the cipher-text query result is de-crypted into plaintext with the private key on the user side. Experimental results show that the method can ensure location privacy and improve query efficiency. At the same time, the balance between privacy protection security and query service quality is achieved.
Data Mining Methods For Malware Detection: A Brief Survey

—Malware is one of the most serious security threats on the Internet today. Unfortunately, the number of new malware samples has explosively increased. Anti-malware vendors are now confronted with millions of potential malware samples per year. In the recent decade, data mining techniques have been concentrated for malware detection. This article investigates the use of data mining methods for malware detection, providing a comprehensive investigation on both the data prepossessing methods and the classiﬁcation/clustering techniques.
Framework for Efficient Auto-Scaling of Virtual Network Functions in a Cloud Environment

Network Function Virtualization (NFV) offers an alternate method to design, deploy and manage network services. The NFV decouples network functions from the dedicated hardware and moves them to the virtual servers so that they can run in the software. One of the major strengths of the NFV is its ability to dynamically extend or reduce resources allocated to Virtual Network Functions (VNF) as needed and at run-time. There is a need for a comprehensive metering component in the cloud to store and process the metrics/samples for efficient auto-scaling or load-management of the VNF. In this paper, we propose an integrating framework for efficient auto-scaling of VNF using Gnocchi; a time-series database that is integrated within the framework to store, handle and index the time-series data. The objective of this study is to validate the efficacy of employing Gnocchi for auto-scaling of VNF, in terms of aggregated data points, database size, data recovery speed, and memory consumption. The employed methodology is to perform a detailed empirical analysis of the proposed framework by deploying a fully functional cloud to implement NFV architecture using several OpenStack components including Gnocchi. Our results show a significant improvement over the legacy Ceilometer configuration in terms of lower metering storage size, less memory utilization in processing and management of metrics, and reduced time delay in retrieving the monitoring data to evaluate alarms for the auto-scaling of VNF.
Existence of solutions to contact mean - ﬁ eld games of ﬁ rst order

: This paper deals with the existence of solutions of a class of contact mean - ﬁ eld game systems of ﬁ rst order consisting of a contact Hamilton - Jacobi equation and a continuity equation. Evans found a connection between Hamilton - Jacobi equations and continuity equations from the weak KAM point of view, where the coupling term is zero. Inspired by his work, we prove the main existence result by analyzing the properties of the Mather set for contact Hamiltonian systems.
Non-equilibirum ionization and cooling of metal-enriched gas in the presence of a photoionization background

Simulations of the formation of galaxies, as well as ionisation models used to interpret observations of quasar absorption lines, generally either assume ionisation equilibrium or ignore the presence of the extra-galactic background (EGB) radiation. We introduce a method to compute the non-equilibrium ionisation and cooling of diffuse gas exposed to the EGB. Our method iterates the ionisation states of the 11 elements that dominate the cooling and uses tabulated ion-by-ion cooling and photo-heating efficiencies to update the temperature of the gas. Our reaction network includes radiative and di-electric recombination, collisional ionisation, photo-ionisation, Auger ionisation, and charge transfer. We verify that our method reproduces published results for collisional equilibrium, collisional non-equilibrium, and photo-ionised equilibrium. Non-equilibrium effects can become very important in cooling gas, particularly below 10^6 K. Photo-ionisation and non-equilibrium effects both tend to boost the degree of ionisation and to reduce cooling efficiencies. The effect of the EGB is larger for lower densities. Hence, photo-ionisation affects cooling more under isochoric than under isobaric conditions. Non-equilibrium effects are smaller in the presence of the EGB and are thus overestimated when using collisional-only processes. The inclusion of the EGB alters the observational diagnostics of diffuse, metal-enriched gas (e.g. metal absorption lines) even more significantly than the cooling efficiencies. We argue that the cooling efficiency should be considered if ionisation models are used to infer physical conditions from observed line ratios, as the a priori probability of observing gas is lower if its cooling time is shorter. We provide on-line tables of ionisation fractions and cooling efficiencies for equilibrium and non-equilibrium scenarios. (abridged)
THEORY AND MODELS UNDERLYING ETHICAL INVESTMENT RESEARCH

The purpose of this article is to explore in depth the literature on the theories and models that underlie ethical investment research. Through a literature review study, the research found 10 journals that are ready to be reviewed. The literature search found several theories and models that underlie ethical investment research. The theories and models include agency theory, Angel and Rivoli model (1997), Heinkel, Krause and Zechner model (2001), Barnea, Heinkel and Krause model (2005) and Hypothesis Model of Ethical Investment and Stock Price Relationship of Derwall, Koedijk and Ter Horst (2011). “socially “values-based investing”, “sustainable investment”, “mission social investment, The shunned-stock hypothesis is based on two assumptions (i) ethical investors are value driven, not related to the profit motive. The motivation of these investors' decisions varies between purely emotional or social norms. (ii) in order to be able to influence the price of securities, value-based investors must be large enough, for example there are 10% ethical-based investors from the total number of investors in the financial market. Value-based investors primarily use “negative” screening to avoid ethically controversial stocks. The errors-in-expectations hypothesis explains that ethical stocks have higher risk-adjusted returns. This is because the market is slow to recognize the positive impact of implementing CSR on the company's expected cash flow or the market systematically underestimates the importance of CSR in influencing the company's expected cash flow. Investors in the hypothesis are profit-oriented investors and use positive screening in the selection of financial assets. There are several requirements for the errors-in-expectations hypothesis. (i) the expected future cash flows should be related to the use of CSR practices. (ii) stock prices should not reflect all value-related information related to CSR practices, because superior profits from CSR can only be a source of abnormal returns to the extent that investors do not expect them.
Dark energy, inflation and dark matter from modified F(R) gravity

We review modified $F(R)$ gravity as realistic candidate to describe the observable universe expansion history. We show that recent cosmic acceleration, radiation/matter-dominated epoch and inflation could be realized in the framework of $F(R)$-gravity in the unified way. For some viable classes of $F(R)$-gravity, the Newton law is respected and there is no so-called matter instability (the very heavy positive mass for additional scalar degree of freedom is generated). The reconstruction program in modified gravity is also reviewed and it is demonstrated that {\it any} time-evolution of the universe expansion could be realized in $F(R)$-gravity. These models remain to be realistic also in the presence of non-minimal gravitational coupling with usual matter. It is shown that same model which passes local tests and predicts the unification of inflation with cosmic acceleration also describes dark matter thanks to presence of additional scalar degree of freedom and chameleon mechanism.
Origin of cosmic rays and evolution of spallogenic nuclides Li, Be and B

Abstract A short overview is presented of current issues concerning the production and evolution of Li, Be and B in the Milky Way. In particular, the observed “primary-like” evolution of Be is re-assessed in the light of a novel idea: it is argued that Galactic Cosmic Rays are accelerated from the wind material of rotating massive stars, hit by the forward shock of the subsequent supernova explosions. The pre-galactic levels of both Li isotopes remain controversial at present, making it difficult to predict their Galactic evolution. A quantitative estimate is provided of the contributions of various candidate sources to the solar abundance of Li.
Associations Between MSTN/HaeIII Polymorphism and Reproductive and Growth Characteristics in Morkaraman Sheep Morkaraman Koyunlarında MSTN/HaeIII Polimorfizmi İle Dölverimi ve Büyüme Özellikleri Arasındaki İlişkiler

: The myostatin gene inhibits skeletal muscle growth in advanced animals, and a mutation in the gene coding region increases muscle formation. Hence, it is accepted to be a candidate gene for the selection of some production traits. The objective of the current research was to examine the genotypes of the myostatin gene and reveal the associations between the genotypes and a number of traits, including birth weight, weaning weight, weaning age, average daily weight gain, and productivity, in 110 Morkaraman sheep. Genotypes were determined by the PCR-RFLP method using the Hae III restriction enzyme, and the genotype frequencies were found to be 9%, 69%, and 22% for MM, Mm, and mm in the myostatin locus, respectively. The M allele frequency was 44%, whereas the m allele frequency was 56%. In the studied population, the myostatin locus was not in Hardy-Weinberg equilibrium. The association analysis revealed no statistically significant impact of the MSTN gene polymorphism in exon 3 on birth weight, weaning weight, and productivity (P>0.05) but found a significant effect on weaning age and average daily weight gain (P<0.05). As a result, the MSTN gene showed polymorphisms in Morkaraman sheep and can be regarded as a genetic marker for sheep selection according to the association analysis results.
Short- and Mid-Term Survival Prediction in Patients with Acute Type A Aortic Dissection Undergoing Surgical Repair: Based on the Systemic Immune-Inflammation Index

Purpose The postoperative survival of patients with acute type A aortic dissection (aTAAD) remains unsatisfactory. The current study developed an easy-to-use survival prediction model and calculator. Methods A total of 496 patients with aTAAD undergoing surgical repair were included in this study. The systemic immune-inflammation index (SII) and other clinical features were collected and subjected to logistic and Cox regression analyses. The survival prediction model was based on Cox regression analyses and exhibited as a nomogram. For convenience of use, the nomogram was further developed into calculator software. Results We demonstrated that a higher preoperative SII was associated with in-hospital death (OR: 4.116, p < 0.001) and a higher postoperative overall survival rate (HR: 2.467, p < 0.001) in aTAAD patients undergoing surgical repair. A survival prediction model and calculator based on SII and four other clinical features were developed. The overall C-index of the model was 0.743. The areas under the curves (AUCs) of the 1- and 3-month and 1- and 3-year survival probabilities were 0.73, 0.71, 0.71 and 0.72, respectively. The model also showed good calibration and clinical utility. Conclusion Preoperative SII is significantly associated with postoperative survival. Based on SII and other clinical features, we created the first easy-to-use prediction model and calculator for predicting the postoperative survival rate in aTAAD patients, which showed good prediction performance.
Silver Diamine Fluoride (SDF) Efficacy in Arresting Cavitated Caries Lesions in Primary Molars: A Systematic Review and Metanalysis

A systematic review and meta-analysis were carried out to evaluate the efficacy of silver diamine fluoride (SDF) in controlling caries progression in cavitated primary molars. A search for randomized and non-randomized trials with follow-up > 6 months was performed using PubMed, Scopus and Embase. The Cochrane risk of bias tools were used for the quality assessment. The success rate and odds ratios were chosen to calculate the effect size for the meta-analysis. A total of 792 papers were identified and 9 were selected. A high variability regarding SDF application protocol was found; otherwise, caries arrest was always recorded using visual/tactile methods. Two studies were judged at low risk of bias, six at moderate risk and one at high risk. Data from five studies were aggregated for meta-analysis. Heterogeneity was found moderate (I2 = 35.69%, p = 0.18). SDF application was found to be overall effective (fixed effect model) in arresting caries progression (ES = 0.35, p < 0.01). In a total of 622 arrested lesions, out of 1205 considered, the caries arrest rate was 51.62% ± 27.40% (Confidence = 1.55) using SDF ≥ 38% applied annually or biannually. In conclusion, when applied to active cavitated caries lesions in primary molars, SDF appears to be effective in arresting dental caries progression, especially if applied biannually.
Investigation of Direct Band Gap Solar Cells through the use of Cs-Sb-Halide Double Perovskites

—Perovskites composed of cesium, antimony, and a halide were synthesized using solid-state synthesis techniques. These compounds were analyzed with XRD and UV-Vis. Solar cells were fabricated using these perovskites, and the efﬁciencies of the cells were measured. It was found that the perovskites fabricated were impure according to their XRD spectra, indi-cating problems in synthesis. The compounds had comparable band gaps to their methylammonium-lead-halide perovskite counterparts according to UV-Vis data. The solar cells had very poor efﬁciencies, failing to produce any power in almost every case.