Miracle-dz/UniFAR-FTUs huggingface dataset:
Lifetime Network Externality and the Dynamics of Group Inequality

The quality of one’s social network significantly affects his economic success. Even after the skill acquisition period, the social network influences economic success through various routes such as mentoring, job searching, business connections, or information channeling. In this paper I propose that a social network externality which extends beyond the education period – what I call a Lifetime Network Externality – is important in explaining the evolution of between-group inequality in an economy. When the members of a group believe that the quality of their social network will be better in the future, more young group members invest in skill achievement because they expect higher returns on investment realized over the working period. As this is repeated in the following generations, the quality of the group’s network improves over time. Combining the Lifetime Network Externality, which operates during the labor market phase of a worker’s career, with the traditional concepts of peer and parental effects, which operate during the educational phase (Loury 1977), I suggest a full dynamic picture of group inequality in an economy with multiple social groups. I define a notion of Network Trap, wherein a disadvantaged group cannot improve the quality of its network without a governmental intervention, and I explore the egalitarian policies to mobilize the group out of this trap. This social capital approach suggests a positive effect of equality on economic growth in later stages of economic development and a positive effect of inequality in the early stage of economic development, consistent with Galor and Zeira (1993). Unlike the previous literature, the conclusion is derived without imposing the standard assumption of credit market imperfections. Therefore, this implies that equality, by helping disadvantaged groups to move out of the network trap, has a positive effect on economic development even in a matured economy without binding credit constraints, or in a society with public provision of schooling.
On the mass-metallicity relation, velocity dispersion, and gravitational well depth of GRB host galaxies

We analyze a sample of 16 absorption systems intrinsic to long duration GRB host galaxies at $z \gtrsim 2$ for which the metallicities are known. We compare the relation between the metallicity and cold gas velocity width for this sample to that of the QSO-DLAs, and find complete agreement. We then compare the redshift evolution of the mass-metallicity relation of our sample to that of QSO-DLAs and find that also GRB hosts favour a late onset of this evolution, around a redshift of $\approx 2.6$. We compute predicted stellar masses for the GRB host galaxies using the prescription determined from QSO-DLA samples and compare the measured stellar masses for the four hosts where stellar masses have been determined from SED fits. We find excellent agreement and conclude that, on basis of all available data and tests, long duration GRB-DLA hosts and intervening QSO-DLAs are consistent with being drawn from the same underlying population. GRB host galaxies and QSO-DLAs are found to have different impact parameter distributions and we briefly discuss how this may affect statistical samples. The impact parameter distribution has two effects. First any metallicity gradient will shift the measured metallicity away from the metallicity in the centre of the galaxy, second the path of the sightline through different parts of the potential well of the dark matter halo will cause different velocity fields to be sampled. We report evidence suggesting that this second effect may have been detected.
Stochastic stabilization of the chaotic finance system via adaptive fixed-time control

This investigation concentrates on the stochastic fixed-time stabilization(SFxS) of the chaotic finance sys-tem(CFS) in noisy environment. The adaptive control and fixed-time control techniques are integrated successfully, which not only can stabilize the CFS within a fixed-time, but also not necessary to determine the related controlling gains beforehand. Particularly, the adaptive fixed-time control protocol is continuous and smooth, which strips out the signum function from the conventional fixed-time control schemes so that the chattering phenomenon can be eliminated effectively. Furthermore, according to the theory of stochastic fixed-time stability, the sufficient condition is deduced and the upper bound estimation of settling time(UPT) is also obtained, which is irrelevant to the initial states of CFS. Finally, simulation results validate the correctness and effectiveness of theoretical analysis.
Pulse profile stability of the Crab pulsar

We present an X-ray timing analysis of the Crab pulsar, PSR B0531+21, using archival RXTE data. We have investigated the stability of the Crab pulse profile, in soft (2–20 keV) and hard (30–100 keV) X-ray energies, over the last decade of RXTE operation. The analysis includes measurement of the separation between the two pulse peaks and the intensity and widths of the two peaks. We did not find any significant time dependency in the pulse shape. The two peaks have been stable in phase, intensity and width for the last ten years. The first pulse is relatively stronger at soft X-rays. The first pulse peak is narrower than the second peak in both soft and hard X-ray energies. Both the peaks show a slow rise and a steeper fall. The ratio of the pulsed photons in the two peaks is also constant in time.
Analysis of coupled axial-torsional vibration of drill-string with an inclination angle

Drill-string vibration has a great negative influence on the safety and efficiency of geological drilling. Noticing that the influence of drill-string inclination is not well considered in the literature, this paper develops a novel drill-string vibration model for geological drilling with inclined drill-string. First, the correlation between the inclination angle of borehole and the axial and torsional forces on the drill-string is analyzed. Based on this, a drill-string motion model with the parameters of inclination angle is established. Then, the bit-rock interaction is considered as two processes, axial cutting and torsional friction, and an axial-torsional coupled bit-rock interaction model with state-dependent time delay is established. By combining the established drill-string motion model and bit-rock interaction model, a coupled axial-torsional vibration model of drill-string in inclined borehole is obtained with the effect of borehole wall friction taken into account. The drill-string vibration model proposed in this paper is more general, and includes the existing coupled drill-string vibration model of vertical borehole, which is closer to the actual situation.
Coherence in a transmon qubit with epitaxial tunnel junctions

We developed transmon qubits based on epitaxial tunnel junctions and interdigitated capacitors. This multileveled qubit, patterned by use of all-optical lithography, is a step towards scalable qubits with a high integration density. The relaxation time T1 is 0.72−0.86 μs and the ensemble dephasing time T2* is slightly larger than T1. The dephasing time T2 (1.36 μs) is nearly energy-relaxation-limited. Qubit spectroscopy yields weaker level splitting than observed in qubits with amorphous barriers in equivalent-size junctions. The qubit’s inferred microwave loss closely matches the weighted losses of the individual elements (junction, wiring dielectric, and interdigitated capacitor), determined by independent resonator measurements.We developed transmon qubits based on epitaxial tunnel junctions and interdigitated capacitors. This multileveled qubit, patterned by use of all-optical lithography, is a step towards scalable qubits with a high integration density. The relaxation time T1 is 0.72−0.86 μs and the ensemble dephasing time T2* is slightly larger than T1. The dephasing time T2 (1.36 μs) is nearly energy-relaxation-limited. Qubit spectroscopy yields weaker level splitting than observed in qubits with amorphous barriers in equivalent-size junctions. The qubit’s inferred microwave loss closely matches the weighted losses of the individual elements (junction, wiring dielectric, and interdigitated capacitor), determined by independent resonator measurements.
THE PAIR FRACTION OF MASSIVE GALAXIES AT 0 ⩽ z ⩽ 3

Using a mass-selected (M⋆ ⩾ 1011 M☉) sample of 198 galaxies at 0 ⩽ z ⩽ 3.0 with Hubble Space Telescope/NICMOS H160-band images from the COSMOS survey, we find evidence for the evolution of the pair fraction above z ∼ 2, an epoch in which massive galaxies are believed to undergo significant structural and mass evolution. We observe that the pair fraction of massive galaxies is 0.15 ± 0.08 at 1.7 ⩽z ⩽ 3.0, where galaxy pairs are defined as massive galaxies having a companion of flux ratio from 1:1 to 1:4 within a projected separation of 30 kpc. This is slightly lower but still consistent with the pair fraction measured previously in other studies, and the merger fraction predicted in halo-occupation modeling. The redshift evolution of the pair fraction is described by a power law F(z) = (0.07 ± 0.04) × (1 + z)0.6 ± 0.5. The merger rate is consistent with no redshift evolution; however it is difficult to constrain due to the limited sample size and the high uncertainties in the merging timescale. Based on the merger rate calculation, we estimate that a massive galaxy undergoes on average 1.1 ± 0.5 major mergers from z = 3 to 0. The observed merger fraction is sufficient to explain the number density evolution of massive galaxies, but insufficient to explain the size evolution. This is a hint that mechanism(s) other than major merging may be required to increase the sizes of the massive, compact quiescent galaxies from z ∼ 2 to 0.
Swedish Economic Growth and Education Since 1800

The contribution of this paper is twofold. First, it builds and makes use of long-run data from Sweden on formal education that have never been used to date. Second, it provides a quantitative application of recent theoretical work on the link between demographic changes and economic growth through their effect on education. It concludes that changes in longevity may account for as much as 20% of the observed rise in education over the period from 1800-2000 via a horizon effect, but have little impact on income growth over the period. On the contrary, changes in population density and composition are central, mainly thanks to their effect on productivity. Most income growth over this period would not have materialized if demographic variables had stayed constant since 1800.
Warps, bending and density waves excited by rotating magnetized stars: results of global 3D MHD simulations

We report results of the first global three-dimensional magnetohydrodynamic simulations of the waves excited in an accretion disc by a rotating star with a dipole magnetic field misaligned from the star's rotation axis (which is aligned with the disc axis). The main results are the following: (1) If the magnetosphere of the star corotates approximately with the inner disc, then we observe a strong one-armed bending wave (a warp). This warp corotates with the star and has a maximum amplitude between corotation radius and the radius of the vertical resonance. The disc's center of mass can deviate from the equatorial plane up to the distance of z_w\approx 0.1 r. However, the effective height of the warp can be larger, h_w \approx 0.3 r due to the finite thickness of the disc. Stars with a range of misalignment angles excite warps. However, the amplitude of the warps is larger for misalignment angles between 15 and 60 degrees. (2) If the magnetosphere rotates slower, than the inner disc, then a bending wave is excited at the disc-magnetosphere boundary, but does not form a large-scale warp. Instead, high-frequency oscillations become strong at the inner region of the disc. These are (a) trapped density waves which form inside the radius where the disc angular velocity has a maximum, and (b) inner bending waves which appear in the case of accretion through magnetic Raleigh-Taylor instability. These two types of waves are connected with the inner disc and their frequencies will vary with accretion rate. Bending oscillations at lower frequencies are also excited including global oscillations of the disc. In cases where the simulation region is small, slowly-precessing warp forms. Simulations are applicable to young stars, cataclysmic variables, and accreting millisecond pulsars.
Diffraction by a Dielectric Wedge.

Abstract : Three separate investigations were made. The first, based on a spectral decomposition method, was the one on which the contract proposal was originally based. It turned out to have a built-in flaw, which was not discovered, however, until rather late in the analysis. AS a consequence the method was abandoned. Just at that time, attention was drawn to two Soviet papers, both of which claimed to have solved the wedge problem rigorously and completely, though by completely different methods. The first paper, by Zavadskii, was examined and found to be faulty. Efforts made to correct the errors were to no avail. However, a semitrivial result emerged from these studies which, in retrospect, could have been found by elementary methods. The second paper, by Aleksandrova and Khiznyak, also turned out to be faulty, though the complex analysis involved a great deal of study to pin-point exactly where the errors occurred. It was not found possible to solve the problem by their method with the errors corrected. It appears that at the present time there is still no valid and rigorous solution to the wedge problems, though several approximations, particularly Balling's, have appeared in the literature, and should provide useful results in practical applications.
STRUCTURE AND COMPOSITION OF TWO TRANSITIONAL CIRCUMSTELLAR DISKS IN CORONA AUSTRALIS

The late stages of evolution of the primordial circumstellar disks surrounding young stars are poorly understood, yet vital to constraining theories of planet formation. We consider basic structural models for the disks around two ∼10 Myr old members of the nearby RCrA association: RX J1842.9−3532 and RX J1852.3−3700. We present new arcsecond-resolution maps of their 230 GHz continuum emission from the Submillimeter Array and unresolved CO(3–2) spectra from the Atacama Submillimeter Telescope Experiment. By combining these data with broadband fluxes from the literature and infrared fluxes and spectra from the catalog of the Formation and Evolution of Planetary Systems Legacy program on the Spitzer Space Telescope, we assemble a multiwavelength data set probing the gas and dust disks. Using the Monte Carlo radiative transfer code RADMC to model simultaneously the spectral energy distribution and millimeter continuum visibilities, we derive basic dust disk properties and identify an inner cavity of radius 16 AU in the disk around RX J1852.3−3700. We also identify an optically thin 5 AU cavity in the disk around RX J1842.9−3532, with a small amount of optically thick material close to the star. The molecular line observations suggest an intermediate disk inclination in RX J1842.9−3532, consistent with the continuum emission. In combination with the dust models, the molecular data allow us to derive a lower CO content than expected, suggesting that the process of gas clearing is likely underway in both systems, perhaps simultaneously with planet formation.
Signs of magnetic acceleration and multizone emission in GRB 080825C

One of the major results from the study of gamma-ray bursts with the Fermi Gamma-ray Space Telescope has been the confirmation that several emission components can be present in the energy spectrum. Here, we reanalyse the spectrum of GRB 080825C using data from the Fermi-Large Area Telescope (LAT) and Gamma-ray Burst Monitor instruments. Although fairly weak, it is the first gamma-ray burst detected by the Fermi-LAT. We improve on the original analysis by using the LAT Low Energy events covering the 30–100 MeV band. We find evidence of an additional component above the main emission peak (modelled using a Band function) with a significance of 3. 5σ in two out of the four time bins. The component is well fitted by a Planck function, but shows unusual behaviour: the peak energy increases in the prompt emission phase, reaching energies of several MeV. This is the first time such a trend has been seen, and implies that the origin of this component is different from those previously detected. We suggest that the two spectral components likely arise in different regions of the outflow, and that strong constraints can be achieved by assuming one of them originates from the photosphere. The most promising model appears to be that the high-energy peak is the result of photospheric emission in a Poynting flux dominated outflow where the magnetization increases with time.
Point defects and clustering in uranium dioxide by LSDA+U calculations

A comprehensive investigation on point defects and their clustering behavior in nonstoichiometric uranium dioxide $\mathrm{U}{\mathrm{O}}_{2\ifmmode\pm\else\textpm\fi{}x}$ is carried out using the $\mathrm{LSDA}+\mathrm{U}$ method based on density functional theory. Accurate energetic information and charge transfers available so far are obtained. With these energies that have improved more than 50% over that of pure generalized gradient approximation and local density approximation, we show that the density functional theory predicts the predominance of oxygen defects over uranium ones at any compositions, which is possible only after properly treating the localized $5f$ electrons. Calculations also suggest an upper bound of $x\ensuremath{\sim}0.03$ for oxygen clusters to start off. The volume change induced by point uranium defects is monotonic but nonlinear, whereas for oxygen defects, increasing $x$ always reduces the system volume linearly, except dimers that require extra space for accommodation, which has been identified as a metastable ionic molecule. Though oxygen dimers usually occupy Willis ${\mathrm{O}}^{\ensuremath{''}}$ sites and mimic a single oxygen in energetics and charge state, they are rare at ambient conditions. Its decomposition process and vibrational properties have been studied carefully. To a general clustering mechanism in anion-excess fluorites systematically obtain, we also analyze the local stabilities of possible basic clustering modes of oxygen defects. The result shows a unified way to understand the structure of Willis-type and cuboctahedral clusters in $\mathrm{U}{\mathrm{O}}_{2+x}$ and $\ensuremath{\beta}\text{\ensuremath{-}}{\mathrm{U}}_{4}{\mathrm{O}}_{9}$. Finally, we generalize the point defect model to the independent cluster approximation to include clustering effects; the impact on defect populations is discussed.
Open statistical ensemble: new properties (scale invariance, application to small systems, meaning of surface particles, etc.)

A new statistical ensemble is examined using the example of classical one-component simple fluid. It's logical to call it an open ensemble, because its peculiarity is the inclusion in the consideration some surrounding area. Calculations point to the necessity of taking into account the restricting surface, exactly when the system is not separated by anything from the bath, and the whole medium is uniform. The "surface tension coefficient", included in the partition function corresponds to the interface of the fluid and hard solid, due to the strict compliance of probability and potential limitations. The number of surface particles corresponds exactly to near surface number density distortions (oscillations) arising in the neighborhood of fluctuation cavities. In contrast to grand canonical ensemble, an open statistical ensemble satisfies the scale invariance requirement: general term of the included subsystem distribution corresponds to that of the original system. It is this ensemble which should be used where consideration of a truly open system is required, since it properly integrates the surface terms. Furthermore, this ensemble may be employed in studies of small systems, since it has no lower limits for the volume of the system. Finally, it is useful in the investigation of fluctuations. For example, it demonstrates that the variance (the mean square deviation) of the number of particles is divided into the bulk and surface terms.
Ageism and Its Impact on Information and Communications Technology Usage and Design

This study sought to understand how adults 65 years and older use Information and Communications Technology (ICT), the barriers and difficulties they experience when using ICT, and how ICT could be improved for older adults. ICT is a vast field, and for this study, ICT was limited to broadband internet, laptop or desktop computers, smartphones, and tablets. A convenience sampling approach was used to identify study participants. Data were gathered in 2021 through 15 qualitative interviews with adults ranging in age from 65 to 87; all resided in the United States. Interviews were conducted via phone and video conferencing technology. Bronfenbrenner’s ecological systems model was the overarching conceptual framework used to understand system influences that help explain older adults’ relationship with ICT and how this may change over time due to environmental forces and factors. Other models and theories considered in this study were the relative deprivation theory and the technology readiness and acceptance model.
Event-Triggered Asynchronous Fault Detection for Stochastically Switched Systems With Sojourn Probabilities†

This paper investigates the event-triggered asynchronous fault detection (FD) problem for discrete-time switched systems with sojourn probabilities. We propose a novel asynchronous FD filter (FDF), of which the sojourn probability is related to the mode of the switched system. A hybrid adjusting variables-dependent event-triggered mechanism (ETM) is devised to reduce the waste of network resources. We construct a new Lyapunov function that contains the mode of the switched system and a flexible variable in the ETM. A sufficient condition in terms of matrix inequalities is obtained under which the error dynamics is stochastically stable with a prescribed $H_{\infty}$ performance. The parameters of the FDF are explicitly given based on the feasible solutions to these matrix inequalities. A numerical example is provided to demonstrate the effectiveness of the proposed event-triggered asynchronous FD method.
Silicate condensation in Mira variables

We study whether the condensation of silicate dust in Mira envelopes could be caused by cluster formation by the abundant SiO molecules. For a simplified model of the pulsational motions of matter in the the outer layers of a Mira variable which is guided by a numerical model for Mira pulsations, the equations of dust nucleation and growth are solved in the co-moving frame of a fixed mass element. It is assumed that seed particles form by clustering of SiO molecules. The calculation of the nucleation rate is based on the experimental data of Nuth and Donn (1982). The quantity of dust formed is calculated by a moment method and the calculation of radiation pressure on the dusty gas is based on a dirty silicate model. Dust nucleation occurs in the model at the upper culmination of the trajectory of a gas parcel where it stays for a considerable time at low temperatures while subsequent dust growth occurs during the descending part of the motion and continues after the next shock reversed motion. It is found that sufficient dust forms that radiation pressure exceeds gravitational pull of the stars such that the mass element is finally driven out of the star. Nucleation of dust particles by clustering of the abundant SiO molecules could be the mechanism that triggers silicate dust formation in Miras.