Miracle-dz/UniFAR-FTUs huggingface dataset:
Periodicities in Saturn's magnetosphere

Although the exact rotation period of Saturn is unknown, Saturn's magnetosphere displays an abundance of periodicities near ~10.7 h. Such modulations appear in charged particles, magnetic fields, energetic neutral atoms, radio emissions, motions of the plasma sheet and magnetopause, and even in Saturn's rings themselves. Known to an accuracy of four significant figures, these periodicities do not remain constant but vary by ~1% over time scales of a year or longer. Magnetospheric periodicities also display slightly different periods in the northern and southern hemispheres: ~10.6 h and ~10.8 h, respectively. The magnetic and spin axes of Saturn are aligned to within ~1°, so that Saturn's magnetospheric periodicities cannot be explained as “wobble” caused by a geometric tilt, unlike those of the Earth and Jupiter. Furthermore, the variations in periodicity argue against a cause related to changes interior to an object as large as Saturn. Several models have been proposed for the periodicities, including rotating planetary vortices, periodic plasma releases, and a flapping magnetodisk, but none can satisfactorily explain all of Saturn's periodicities. This review discusses the observations of these periodicities from their initial discovery during the Pioneer flyby to their long‐term surveillance by Cassini and examines the various struggles to explain and model them. Understanding Saturn's periodicity may elucidate periodic phenomena in other magnetospheric environments.
Intercation Between Some Micro-Elements And Humic Substances in Some Forest Soils Northern Iraq

Four pedons were selected for different soils in the forest cover, two in each of Mankeesh and Atrush areas in Dohuk governorate, under pine and oak trees, in order to study the distribution of the main groups of humic compounds (humic and fulvic acids) and their association with iron and manganese ions. The results showed that the variation in the nature of the forest cover and the speed of decomposition of its remains led to a difference in the distribution of the content of organic matter, the ratios of Humic acid / fulvic acid (FA / HA) and the amount of humic substances produced in each soil, regarding the optical density of the extracted humic compounds, which is expressed as E4/E6, this ratio depends on the chemical composition of these Humic compounds. It is noted from the results that this ratio between E4: E6 ranged between (0.43 - 1.79), low values reflect the presence of aromatic Humic compounds with relatively low molecular weights, while high values indicate the presence of aliphatic humic compounds, the study also showed a difference in the values of iron and manganese associated with humic and fulvic acid as organic complexes, which is consistent with the difference in the degree of decomposition of forest tree residues and plant residues, and in turn is reflected on the quantity and type of humic compounds resulting from the decomposition. The Atrush soil under pine forests excelled in its composition of chelated iron with fulvic acid, Humic acid and manganese chelated with fulvic acid, while the Atrush soil under oak forests excelled in the composition of chelated manganese with humic acid on the rest of the studied soils.
THE OBSERVED M–σ RELATIONS IMPLY THAT SUPER-MASSIVE BLACK HOLES GROW BY COLD CHAOTIC ACCRETION

We argue that current observations of M–σ relations for galaxies can be used to constrain theories of super-massive black holes (SMBHs) feeding. In particular, assuming that SMBH mass is limited only by the feedback on the gas that feeds it, we show that SMBHs fed via a planar galaxy-scale gas flow, such as a disk or a bar, should be much more massive than their counterparts fed by quasi-spherical inflows. This follows from the relative inefficiency of active galactic nucleus feedback on a flattened inflow. We find that even under the most optimistic conditions for SMBH feedback on flattened inflows, the mass at which the SMBH expels the gas disk and terminates its own growth is a factor of several higher than the one established for quasi-spherical inflows. Any beaming of feedback away from the disk and any disk self-shadowing strengthen this result further. Contrary to this theoretical expectation, recent observations have shown that SMBHs in pseudobulge galaxies (which are associated with barred galaxies) are typically under- rather than overmassive when compared with their classical bulge counterparts at a fixed value of σ. We conclude from this that SMBHs are not fed by large (100 pc to many kpc) scale gas disks or bars, most likely because such planar flows are turned into stars too efficiently to allow any SMBH growth. Based on this and other related observational evidence, we argue that most SMBHs grow by chaotic accretion of gas clouds with a small and nearly randomly distributed direction of angular momentum.
Gamma-Ray Burst Observations at High Energy with the Fermi Large Area Telescope

The Fermi Gamma-ray Space Telescope with its main instrument onboard, the Large Area Telescope (LAT), opened a new era in high-energy astrophysics and in particular for the study of Gamma-Ray Bursts (GRBs), which are short flashes of -rays associated with the brightest and most distant events ever observed in our universe after the Big Bang. My thesis work focused primarily on the observations of this phenomenon with the LAT (20 MeV - 300 GeV) and the Gamma-ray Burst Monitor (10 keV - 40 MeV) onboard the Fermi satellite. After describing the procedure used for detection and analysis of LAT GRBs, I will provide an overview of the temporal and spectral features observed during the prompt emission of these events after one year and a half of operation for Fermi. GRBs can also be used as a tool to probe interesting physics. My focus will be on the detection of very high energy photons (typically above 10 GeV) associated with LAT GRBs and which were used to set significant constraints both on a possible violation of Lorentz invariance - which postulates that all observers measure exactly the same speed of light in vacuum, independently of photon energy - and on the Optical-Ultraviolet extragalactic background light in the Universe.
THE LA SILLA–QUEST KUIPER BELT SURVEY

We describe the instrumentation and detection software and characterize the detection efficiency of an automated, all-sky, southern-hemisphere search for Kuiper Belt Objects (KBOs) brighter than R mag 21.4. The search relies on Yale University's 160 Megapixel QUEST camera, previously used for the successful surveys at Palomar that detected most of the distant dwarf planets, and now installed on the ESO 1.0 m Schmidt telescope at La Silla, Chile. Extensive upgrades were made to the telescope control system to support automation, and significant improvements were made to the camera. To date, 63 new KBOs have been discovered, including a new member of the Haumea collision family (2009 YE7) and a new distant object with an inclination exceeding 70° (2010 WG9). In a survey covering ∼7500 deg2, we have thus far detected 77 KBOs and Centaurs, more than any other full-hemisphere search to date. Using a pattern of dithered pointings, we demonstrate a search efficiency exceeding 80%. We are currently on track to complete the southern-sky survey and detect any bright KBOs that have eluded detection from the north.
Information sharing and fund performance: Evidence from the US mutual fund family

ABSTRACT In this paper, we investigate the information sharing within an organisation and its consequences on mutual fund performance. Using a sample from the US open-end mutual fund industry, information sharing inside an organisation is quantified via the dependence of individual funds from the fund family joint information set. The findings indicate a positive relationship between the degree of information sharing and the resulting fund performance. This remains robust across different performance evaluation metrics and various model specifications. Such superior performance can be attributed to the quality of information shared across affiliated fund members and timely information diffusion within the fund family.
THE RADIAL DISTRIBUTION OF X-RAY BINARIES AND GLOBULAR CLUSTERS IN NGC 4649 AND THEIR RELATION WITH THE LOCAL STELLAR MASS DENSITY

We investigate the radial distribution of the low-mass X-ray binary (LMXB) population in the elliptical galaxy NGC 4649, using Chandra and Hubble data to separate the field and globular cluster (GC) populations. GCs with LMXBs have the same radial distribution as the parent red and blue GCs. The radial profile of field LMXBs follows the V-band profile within the D25 of NGC 4649. Using the spatial information provided by our data, we find that the global galaxy-wide relations among cumulative number and luminosity of LMXBs and the integrated stellar mass hold on local scales within D25. An excess of field LMXBs with respect to the V-band light is observed in the galaxy's outskirts, which may be partially due to unidentified GC sources or to a rejuvenated field LMXB population caused by past merging interactions.
Interacting dark energy and transient accelerated expansion

We argue that interactions in the dark sector may have a crucial impact on the cosmological dynamics. In particular, the future cosmic evolution may be very different from that predicted by the LCDM model. An example is a scenario in which the currently observed accelerated expansion is an interaction-induced transient phenomenon. We discuss such type of behavior on the basis of a two-fluid toy model.
DISCOVERY OF TIDAL TAILS AROUND THE DISTANT GLOBULAR CLUSTER PALOMAR 14

We report the detection of a pair of degree-long tidal tails associated with the globular cluster Palomar 14, using images obtained at the Canada–France–Hawaii Telescope. We reveal a power-law departure from a King profile at large distances to the cluster center. The density map constructed with the optimal matched filter technique shows a nearly symmetrical and elongated distribution of stars on both sides of the cluster, forming an S-shape characteristic of mass loss. This evidence may be the telltale signature of tidal stripping in action. This, together with its large Galactocentric distance, imposes strong constraints on its orbit and/or origin: (1) it must follow an external orbit confined to the peripheral region of the Galactic halo and/or (2) it formed in a satellite galaxy later accreted by the Milky Way.
MOLECULAR DISTRIBUTION IN THE SPIRAL ARM OF M51

Molecular line images of 13CO, C18O, CN, CS, CH3OH, and HNCO are obtained toward the spiral arm of M51 at a 7 ″ × 6 ″ ? > resolution with the Combined Array for Research in Millimeter-wave Astronomy. Distributions of the molecules averaged over a 300 pc scale are found to be almost similar to one another and to essentially trace the spiral arm. However, the principal component analysis shows a slight difference of distributions among molecular species, particularly for CH3OH and HNCO. These two species do not correlate well with the star formation rate, implying that they are not enhanced by local star formation activities but by galactic-scale phenomena such as spiral shocks. Furthermore, the distributions of HNCO and CH3OH are found to be slightly different, and their origins deserve further investigation. The present results provide us with an important clue for understanding the 300 pc scale chemical composition in the spiral arm and its relation to galactic-scale dynamics.
Dust-to-gas ratio, XCO factor and CO-dark gas in the Galactic anticentre: an observational study

We investigate the correlation between extinction and H~{\sc i} and CO emission at intermediate and high Galactic latitudes ($|b|>10\degr$) within the footprint of the Xuyi Schmidt Telescope Photometric Survey of the Galactic anticentre (XSTPS-GAC) on small and large scales. In Paper I (Chen et al. 2014), we present a three-dimensional dust extinction map within the footprint of XSTPS-GAC, covering a sky area of over 6,000\,deg$^2$ at a spatial angular resolution of 6\,arcmin. In the current work, the map is combined with data from gas tracers, including H~{\sc i} data from the Galactic Arecibo L-band Feed Array H~{\sc i} survey and CO data from the Planck mission, to constrain the values of dust-to-gas ratio $DGR=A_V/N({\rm H})$ and CO-to-$\rm H_2$ conversion factor $X_{\rm CO}=N({\rm H_2})/W_{\rm CO}$ for the entire GAC footprint excluding the Galactic plane, as well as for selected star-forming regions (such as the Orion, Taurus and Perseus clouds) and a region of diffuse gas in the northern Galactic hemisphere. For the whole GAC footprint, we find $DGR=(4.15\pm0.01) \times 10^{-22}$\,$\rm mag\,cm^{2}$ and $X_{\rm CO}=(1.72 \pm 0.03) \times 10^{20}$\,$\rm cm^{-2}\,(K\,km\,s^{-1})^{-1}$. We have also investigated the distribution of "CO-dark" gas (DG) within the footprint of GAC and found a linear correlation between the DG column density and the $V$-band extinction: $N({\rm DG}) \simeq 2.2 \times 10^{21} (A_V - A^{c}_{V})\,\rm cm^{-2}$. The mass fraction of DG is found to be $f_{\rm DG}\sim 0.55$ toward the Galactic anticentre, which is respectively about 23 and 124 per cent of the atomic and CO-traced molecular gas in the same region. This result is consistent with the theoretical work of Papadopoulos et al. but much larger than that expected in the $\rm H_2$ cloud models by Wolfire et al.
The Effect of Urbanization and Industrialization on Tourism Revenues: The Case of Turkey

Tourism revenues constitute a significant and growing part of the Turkish economy. This paper aims to examine the impact of urbanization and industrialization on tourism revenues in Turkey. Time-series analysis is conducted for the period 1990 to 2020. Empirical evidence of this paper supports the presence of cointegration vectors and therefore confirms the long-run relationship between the variables of interest. Fully modified OLS, dynamic OLS, and canonical cointegration regressions are used for the long and short-run estimations. The results indicate the significant positive effect of urbanization on tourism receipts. Industrialization, on the other hand, has a significantly negative effect on tourism revenues. This study suggests the formulation of policy by the policymakers in Turkey that will ensure increase of resources allocation to the leading economic sector that will enable a spread-effect to tourism revenue.
Evaluation of university students' knowledge, attitudes, and practices on food safety in Bolu, Türkiye

This study aims to assess the food safety knowledge, attitudes, and practices of university students in Türkiye. A cross-sectional study was conducted with the participation of 630 university students from the departments of Gastronomy and Culinary Arts (GCA), Food Engineering (FE), Nursing (NUR), and Physical Therapy and Rehabilitation (PTR) in Bolu, Türkiye. The GCA students scored the highest (25.46 ±2.85) and the NUR students scored the lowest (21.81 ±3.27) on food safety knowledge. The GCA students scored the highest (51.42 ±5.58) and the NUR students scored the lowest (49.00 ±6.07) on food safety attitudes. The FE students scored the highest (10.12 ±1.69) and the NUR students scored the lowest (9.69 ±1.77) on food safety practices. The students who took a course on food safety had significantly higher scores on food safety knowledge, attitudes, and practices than those who did not. Although the students' food safety scores were above average, they had a lack of knowledge and concerns in many areas. It was emphasized the importance of food safety education to fill the knowledge gaps and thus to prevent foodborne illnesses.
A weakly non‐linear theory for spiral density waves excited by accretion disc turbulence

We develop an analytic theory to describe spiral density waves propagating in a shearing disc in the weakly non-linear regime. Such waves are generically found to be excited in simulations of turbulent accretion discs, in particular if the said turbulence arises from the magnetorotational instability (MRI). We derive a modified Burgers equation governing their dynamics, which includes the effects of non-linear steepening, dispersion and a bulk viscosity to support shocks. We solve this equation approximately to obtain non-linear sawtooth solutions that are asymptotically valid at late times. In this limit, the presence of shocks is found to cause the wave amplitude to decrease with time as t −2 . The validity of the analytic description is confirmed by direct numerical solution of the full non-linear equations of motion. The asymptotic forms of the wave profiles of the state variables are also found to occur in MRI simulations, indicating that dissipation due to shocks plays a significant role apart from any effects arising from direct coupling to the turbulence.
The influence of teaching motivations on student engagement in an online learning environment in China

Given the importance of student engagement for educational success, it is essential to explore how teachers can stimulate student engagement in online learning environment. However, relatively little research drawing from self-determination theory has examined the links between teaching motivations and student engagement. To this end, this study was conducted to survey 414 Chinese college students’ perceptions of teaching motivations, their own intrinsic and extrinsic motivations during the learning process, as well as their engagement with online learning. The findings indicated that the survey had satisfactory validity and internal consistency. Structural equation model revealed the interrelationships between autonomy-supportive teaching motivations, controlling teaching motivations, student intrinsic and extrinsic motivations, and student engagement. The results showed that in online learning environments, autonomy-supportive teaching motivations and student intrinsic motivation were positively related to student engagement. Unexpectedly, controlling teaching motivations and student extrinsic motivation had no significant effect on student engagement. Moreover, the mediating effects of student intrinsic motivation including perceived autonomy, competence, and relatedness offered a deeper understanding of the association between autonomy-supportive teaching motivations and student engagement. The main findings and practical implications together are discussed in depth. Implications for practice or policy: Teachers could adopt autonomy-supportive teaching strategies and stimulate students’ intrinsic motivation as they have shown to be positive factors for student engagement. Developers and educators could enhance student engagement through nurturing inner motivational resources in online learning environment. Researchers could verify more factors that influence student engagement and clarify how they could be manipulated in future studies.
Mystery Shopping as a Strategic Management Practice in Multi-Site Firms

IZA DP No. 15599 SEPTEMBER 2022 Mystery Shopping as a Strategic Management Practice in Multi-Site Firms* Anonymous and unannounced site inspections known as “Mystery Shopping” (MS) are common in multi-site service firms, but little is known about the strategic importance of this practice. We conceptualize MS as a monitoring tool firms use to implement the optimal allocation of site resources between salesand service-related activities in the presence of cross-site reputation spillovers, which is to maximize sales while maintaining service standards. Consistent with this view, data from three retail chains reveal (i) low variation in MS scores, (ii) little correlation of MS scores with sales, and iii) high correlation of sites’ MS scores with the likelihood of their supervisors receiving incentive bonuses. Our findings are robust to different estimation specifications, and shed new light on a ubiquitous yet littlestudied management practice. JEL Classification: L10, M31, M41, M52
A statistical model of three-dimensional anisotropy and intermittency in strong Alfvénic turbulence

We propose a simple statistical model of three-dimensionally anisotropic, intermittent, strong Alfv\'enic turbulence, incorporating both critical balance and dynamic alignment. Our model is based on log-Poisson statistics for Elsasser-field increments along the magnetic field. We predict the scalings of Elsasser-field conditional two-point structure functions with point separations in all three directions in a coordinate system locally aligned with the direction of the magnetic field and of the fluctuating fields and obtain good agreement with numerical simulations. We also derive a scaling of the parallel coherence scale of the fluctuations, $l_\parallel \propto \lambda^{1/2}$, where $\lambda$ is the perpendicular scale. This is indeed observed for the bulk of the fluctuations in numerical simulations.
A Review of the Propagation of Pressure Pulses Produced by Small Underwater Explosive Charges.

Abstract : This report reviews, from the point of view of nonlinear acoustics, the propagation of pressure pulses due to small underwater explosions, such as those used in scattering experiments. We have concentrated our attention on the peak-pressure region, as it is here that nonlinear effects are likely to appear. It has been found that for some values of the physical parameters, there are ranges where the nonlinear theory gives values for the peak pressure that are quite close to those predicted by the experimental, (W1/3/R)1.13 fit. This agreement is found for relatively strong pressure pulses. However, it is concluded that for typical charges used in scattering experiments, nonlinear effects must be negligible, except very near the charges. By implication, it is concluded that except for very close ranges where the shock front is too strong to be considered as a weak shock wave, the decay of the pressure peak in such pulses should be as predicted by linear acoustic theory. As this is not found experimentally, it is suggested that some effects may have been present in the experiments that are not represented by the empirical fit. Keywords: Pulse propagation, Explosive charges, Nonlinear lengthening, (JS).
Using particle size distributions to fingerprint suspended sediment sources—Evaluation at laboratory and catchment scales

Applications of sediment source fingerprinting studies are growing globally despite the high costs and workloads associated with the analyses of conventional fingerprint properties on target sediment samples collected using traditional methods. To this end, there is a need to test new fingerprint properties that can overcome these challenges. Sediment particle size could potentially contribute here since it is relatively easy to measure but, until now, has rarely been deployed as a fingerprint itself. Instead, particle size has been used to ensure that source and target sediment samples are more directly comparable on the basis of the fingerprints used. Accordingly, this work examined whether particle size distributions (PSDs) could be used as a reliable fingerprint for apportioning sediment sources, in combination with a grain size un‐mixing model. Application of PSDs as a fingerprint was tested at two scales: (i) in a laboratory setting where soil samples with known PSDs were used to generate artificial mixtures to evaluate un‐mixing model results, and (ii) a catchment setting comparing PSDs in a confluence‐based approach to test if downstream target sediment PSDs could be un‐mixed into the contributions of sediment coming from an upstream and a tributary sampling site. Laboratory results showed that the known proportions of the two, three and four soil samples in the artificial mixtures were predicted accurately using the AnalySize grain size un‐mixing model, giving average absolute errors of 9%, 8% and 6%, respectively. Catchment results showed variable performances when comparing un‐mixing results with sediment budget estimations, with the best results obtained at higher discharge values during storm runoff events. Overall, our results suggest the potential of using PSDs for estimating contributions of sediment sources delivering SS with distinct PSDs when sources are located at short distance to the downstream sampling site.