Miracle-dz/UniFAR-FTUs huggingface dataset:
Individualism and Venture Capital: A Cross-Country Study

We investigate the effect of individualism—a dimension of culture that is strongly associated with entrepreneurship—on venture-capital investments using a large cross-country sample. Our sample consists of 1496 country-year observations and includes 88 countries from 1998 to 2014. Controlling for economic conditions, the legal environment, and different aspects of culture, we find that individualism is positively and significantly related to venture-capital investments and explains 30% of cross-country variation. This result is stable across different subsamples, several measures of venture-capital investments, and even holds when using the political system 200 years ago as an instrument for individualism. The quality of formal institutions (rule of law) and entrepreneurial attitudes (uncertainty avoidance) partially mediate the effect of individualism on venture-capital investments, while economic conditions (GDP per capita) moderate this effect.
Liquid State Machines: Motivation, Theory, and Applications

The Liquid State Machine (LSM) has emerged as a computational model that is more adequate than the Turing machine for describing computations in biological networks of neurons. Characteristic features of this new model are (i) that it is a model for adaptive computational systems, (ii) that it provides a method for employing randomly connected circuits, or even “found” physical objects for meaningful computations, (iii) that it provides a theoretical context where heterogeneous, rather than stereotypical, local gates or processors increase the computational power of a circuit, (iv) that it provides a method for multiplexing different computations (on a common input) within the same circuit. This chapter reviews the motivation for this model, its theoretical background, and current work on implementations of this model in innovative artificial computing devices.
Software defined radio-based general modulation/demodulation platform for enhancing undergraduate communication and networking curricula

We are living in a world of wireless communication and networking and the advances of communication and networking have changed the world fundamentally. Communication and networking courses, especially wireless communication and networking courses, have become an integral part of the Electrical Engineering, Computer Science, and Computer Engineering curricula. Due to costly hardware needed for communication and networking teaching laboratories, many of these courses are taught without a laboratory. Additionally, such hardware based teaching labs lack the flexibility to evolve over time and adapt to different environments. Supported by an NSF TUES type II grant, we have developed a software defined radio (SDR) based general modulation/demodulation platform for enhancing undergraduate communication and networking curricula. In our previous NSF funded CCLI project “Evolvable wireless laboratory design and implementation for enhancing undergraduate wireless engineering education”, we have developed and demonstrated the first nationwide example of evolvable SDR based laboratories for three existing undergraduate courses. In this project, we are developing new lab components that can be adopted by multiple courses ranging from freshman year introductory course to senior year capstone design projects. Specifically, we have developed a SDR based general modulation/demodulation platform with a graphical user interface (GUI). This user-friendly GUI will allow students to adjust RF parameters such as carrier frequency and symbol rate. More importantly, this general modulation/demodulation platform is capable of transmitting many popular modulation schemes such as BPSK, QPSK, 8PSK, 16PSK, 16QAM, 64QAM. Additionally, students are able to observe the transmitted signal in both time and frequency, and observe the constellation of the modulation at both the transmitter and the receiver. Furthermore, this platform enables students to design their own new modulation constellations via the GUI. At the receiver side, the SDR based platform also provides students the functionality of demodulating the data symbols and bits, and compare them with the transmitted data symbols and bits to calculate the symbol error rate (SER) and the bit error rate (BER) under different channel conditions and signal to noise ratios (SNRs). By assigning constellation points in the signal space and evaluating the SER/BER performance of the constellation, students gain hands-on experiences on the digital modulation/demodulation in realistic wireless communication channels. Through collaboration among the three participating institutions (Wright State University, Miami University (a mostly undergraduate serving institution), and Central State University (an HBCU)), the developed SDR based general modulation/demodulation platform will be integrated in undergraduate curricula of all three institutions.
Heavy-ball Algorithms Always Escape Saddle Points

Nonconvex optimization algorithms with random initialization have attracted increasing attention recently. It has been showed that many first-order methods always avoid saddle points with random starting points. In this paper, we answer a question: can the nonconvex heavy-ball algorithms with random initialization avoid saddle points? The answer is yes! Direct using the existing proof technique for the heavy-ball algorithms is hard due to that each iteration of the heavy-ball algorithm consists of current and last points. It is impossible to formulate the algorithms as iteration like xk+1= g(xk) under some mapping g. To this end, we design a new mapping on a new space. With some transfers, the heavy-ball algorithm can be interpreted as iterations after this mapping. Theoretically, we prove that heavy-ball gradient descent enjoys larger stepsize than the gradient descent to escape saddle points to escape the saddle point. And the heavy-ball proximal point algorithm is also considered; we also proved that the algorithm can always escape the saddle point.
Habitability and Spectroscopic Observability of Warm M-dwarf Exoplanets Evaluated with a 3D Chemistry-Climate Model

Planets residing in circumstellar habitable zones offer us the best opportunities to test hypotheses of life’s potential pervasiveness and complexity. Constraining the precise boundaries of habitability and its observational discriminants is critical to maximizing our chances at remote life detection with future instruments. Conventionally, calculations of the inner edge of the habitable zone (IHZ) have been performed using both 1D radiative-convective and 3D general circulation models. However, these models lack interactive 3D chemistry and do not resolve the mesosphere and lower thermosphere region of the upper atmosphere. Here, we employ a 3D high-top chemistry-climate model (CCM) to simulate the atmospheres of synchronously rotating planets orbiting at the inner edge of habitable zones of K- and M-dwarf stars (between Teff = 2600 and 4000 K). While our IHZ climate predictions are in good agreement with general circulation model studies, we find noteworthy departures in simulated ozone and HOx photochemistry. For instance, climates around inactive stars do not typically enter the classical moist greenhouse regime even with high (≳10−3 mol mol−1) stratospheric water vapor mixing ratios, which suggests that planets around inactive M-stars may only experience minor water-loss over geologically significant timescales. In addition, we find much thinner ozone layers on potentially habitable moist greenhouse atmospheres, as ozone experiences rapid destruction via reaction with hydrogen oxide radicals. Using our CCM results as inputs, our simulated transmission spectra show that both water vapor and ozone features could be detectable by instruments NIRSpec and MIRI LRS on board the James Webb Space Telescope.
The Effect of Explicit Pronunciation Instruction on Undergraduate English as a Foreign Language Learners' Vowel Perception

Since English pronunciation errors by Persian speakers are often caused by the transfer of the Persian language sound system, the present study investigated the effect of explicit pronunciation instruction on undergraduate English as a Foreign Language (EFL) learners’ vowel perception enhancement. The nonequivalent group, pretest-posttest design was employed to study two classes of English literature and English teaching students at Kosar University of Bojnord (KUB) as the experimental group (EG) and control group (CG), respectively. A 40-item minimal pair test was developed based on the 3rd edition of the book Ship or Sheep: An Intermediate Pronunciation Course written by Baker (2006). The reliability of the test was estimated 0.75 through KR-21 formula. After the pretest administration, both groups were exposed to the same activities; however, only the EG received the treatment regarding explicit pronunciation instruction. At the end of an eight-week training program, the pretest was used as the posttest. The results of the independent samples t-test from the posttest revealed that the EG had a better performance than the CG, suggesting that EFL learners’ vowel perception can improve if they are explicitly made aware of their pronunciation errors.
Gravitomagnetism and Gravitational Waves in Galileo-Newtonian Physics.

Adopting Schwinger's formalism for inferring Maxwell-Lorentz equations (MLEs) and combining three ingredients: (i) the laws of gravitostatics, (ii) the Galileo-Newton principle of relativity and (iii) existence of gravitational waves which travel in vacuum with a finite speed $c_g$, we inferred two sets of gravito-Maxwell-Lorentz Equations (g-MLEs). One of these sets corresponds to Heaviside's Gravity of 1893 and the other set corresponds to what we call Maxwellian Gravity (MG). HG and MG are mere two mathematical representations of a single physical theory called Heaviside-Maxwellian Gravity (HMG). While rediscovering Heaviside's gravitational field equations following Schwinger's formalism, we found a correction to Heaviside's speculative gravito-Lorentz force law. This work presents a Galilo-Newtonian foundation of gravitomagnetic effects and gravitational waves, caused by time-varying sources and fields, which are currently considered outside the domain of Newtonian physics. The emergence HMG from other well-established principles of physics is also noted, which established its theoretical consistency and fixed the value of $c_g$ uniquely at the speed of light in vacuum. The explanations of certain experimentally verified general relativistic results within HMG are also noted. We also report, a set of new Maxwell-Lorentz Equations, physically equivalent to the standard set, as a byproduct product of the present approach.
Moving planes for domain walls in a coupled system

Abstract The system leading to phase segregation in two-component Bose-Einstein condensates can be generalized to hyperfine spin states with a Rabi term coupling. This leads to domain wall solutions having a monotone structure for a non-cooperative system. We use the moving plane method to prove monotonicity and one-dimensionality of the phase transition solutions. This relies on totally new estimates for a type of system for which no Maximum Principle a priori holds. We also derive that one dimensional solutions are unique up to translations. When the Rabi coefficient is large, we prove that no non-constant solutions can exist.
Some properties of zero-mode wave functions in abelian Chern-Simons theory on the torus

In geometric quantization a zero-mode wave function in abelian Chern-Simons theory on the torus can be defined as $\Psi [ a, \bar{a} ] = e^{- \frac{K(a, \bar{a})}{2}} f (a)$ where $K(a ,\bar{a} )$ denotes a Kahler potential for the zero-mode variable $a \in \mathbb{C}$ on the torus. We first review that the holomorphic wave function $f(a)$ can be described in terms of the Jacobi theta functions by imposing gauge invariance on $\Psi [ a, \bar{a} ]$ where gauge transformations are induced by doubly periodic translations of $a$. We discuss that $f(a)$ is quantum theoretically characterized by ($i$) an operative relation in the $a$-space representation and ($ii$) an inner product of $\Psi [ a, \bar{a} ]$'s including ambiguities in the choice of $K(a ,\bar{a} )$. We then carry out a similar analysis on the gauge invariance of $\Psi [ a , \bar{a} ]$ where the gauge transformations are induced by modular transformations of the zero-mode variable. We observe that$f(a)$ behaves as a modular form of weight 2 under the condition of $|a|^2 = 1$, namely, $\left. f \left( - \frac{1}{a} \right) = a^2 f(a) \right|_{|a|^2 = 1}$. Utilizing specific forms of $f(a)$ in terms of the Jacobi theta functions, we further investigate how exactly $f(a)$ can or cannot be interpreted as the modular form of weight 2; we extract conditions that make such an interpretation possible.
Classical double copy from color kinematics duality: A proof in the soft limit

Classical double copy is an intriguing relationship between classical solutions to a gravity theory and solutions to classical Yang-Mills equations. Although formally inspired by the double copy relation between (quantum) scattering amplitudes in Yang-Mills and perturbative gravity, a direct proof of the former from the latter continues to be under investigation. In this paper, we attempt to prove classical double copy from the color-kinematics duality symmetry of scalar QCD amplitudes in a restricted setting. That is, we consider radiative solutions with classical scattering sources in Yang-Mills theory and perturbative gravity in $Dg4$ spacetime dimensions. We show that when the frequency of radiation is much smaller than the characteristic frequency of the process, then at the subleading order in frequency, the classical double copy relating radiative gluon field to radiative gravitational field can be proved from the color-kinematics duality of scalar QCD amplitudes.
A Generalized Framework for Edge-Preserving and Structure-Preserving Image Smoothing

Image smoothing is a fundamental procedure in applications of both computer vision and graphics. The required smoothing properties can be different or even contradictive among different tasks. Nevertheless, the inherent smoothing nature of one smoothing operator is usually fixed and thus cannot meet the various requirements of different applications. In this paper, we first introduce the truncated Huber penalty function which shows strong flexibility under different parameter settings. A generalized framework is then proposed with the introduced truncated Huber penalty function. When combined with its strong flexibility, our framework is able to achieve diverse smoothing natures where contradictive smoothing behaviors can even be achieved. It can also yield the smoothing behavior that can seldom be achieved by previous methods, and superior performance is thus achieved in challenging cases. These together enable our framework capable of a range of applications and able to outperform the state-of-the-art approaches in several tasks, such as image detail enhancement, clip-art compression artifacts removal, guided depth map restoration, image texture removal, etc. In addition, an efficient numerical solution is provided and its convergence is theoretically guaranteed even the optimization framework is non-convex and non-smooth. A simple yet effective approach is further proposed to reduce the computational cost of our method while maintaining its performance. The effectiveness and superior performance of our approach are validated through comprehensive experiments in a range of applications. Our code is available at https://github.com/wliusjtu/Generalized-Smoothing-Framework.
Horizontal branch morphology: A new photometric parametrization

Context. Theory and observations indicate that the distribution of stars along the horizontal branch of Galactic globular clusters mainly depends on the metal content. However, the existence of globular clusters with similar metal content and absolute age but different horizontal branch morphologies, suggests the presence of another parameter affecting the star distribution along the branch. Aims. To investigate the variation of the horizontal branch morphology in Galactic globular clusters, we define a new photometric horizontal branch morphology index, overcoming some of the limitations and degeneracies affecting similar indices available in the literature. Methods. We took advantage of a sample of 64 Galactic globular clusters, with both space-based imaging data (Advanced Camera for Surveys survey of Galactic globular clusters) and homogeneous ground-based photometric catalogues in five different bands (U, B, V, R, I). The new index, τHB, is defined as the ratio between the areas subtended by the cumulative number distribution in magnitude (I) and in colour (V − I) of all stars along the horizontal branch. Results. This new index shows a linear trend over the entire range in metallicity (−2.35 ≤ [Fe/H] ≤ −0.12) covered by our Galactic globular cluster sample. We found a linear relation between τHB and absolute cluster ages. We also found a quadratic anti-correlation with [Fe/H], becoming linear when we eliminate the age effect on τHB values. Moreover, we identified a subsample of eight clusters that are peculiar according to their τHB values. These clusters have bluer horizontal branch morphology when compared to typical ones of similar metallicity. These findings allow us to define them as the ’second parameter’ clusters in the sample. A comparison with synthetic horizontal branch models suggests that they cannot be entirely explained with a spread in helium content.
Trees and Islands - Machine learning approach to nuclear physics

We implement machine learning algorithms to nuclear data. These algorithms are purely data driven and generate models that are capable to capture intricate trends. Gradient boosted trees algorithm is employed to generate a trained model from existing nuclear data, which is used for prediction for data of damping parameter, shell correction energies, quadrupole deformation, pairing gaps, level densities and giant dipole resonance for large number of nuclei. We, in particular, predict level density parameter for superheavy elements which is of great current interest. The predictions made by the machine learning algorithm is found to have standard deviation from 0.00035 to 0.73.
QSOs sigposting cluster size halos as gravitational lenses: halo mass, projected mass density profile and concentration at z∼0.7

Magnification bias is a gravitational lensing effect that is normally overlooked because it is considered sub-optimal in comparison with the lensing shear. Thanks to the demonstrated optimal characteristics of the sub-millimetre galaxies (SMGs) for lensing analysis, in this work we were able to measure the magnification bias produced by a sample of QSOs acting as lenses, 0.2<z<1.0, on the SMGs observed by Herschel at 1.2<z<4.0. Two different methodologies were successfully applied: the traditional cross-correlation function approach and the Davis-Peebles estimator through stacking technique. The second one was found to be more robust for analysing the strong lensing regime (<20−30 arcsec in our case) and provides the possibility to take into account the positional errors of the sources in our samples. From the halo modelling of the cross-correlation function, the halo mass where the QSOs acting as lenses are located was estimated to be greater than log 10(Mmin/M⊙) > 13.6−0.4+0.9, also confirmed by the mass density profile analysis (M200c∼ 1014 M⊙). These mass values indicate that we are observing the lensing effect of a cluster size halo signposted by the QSOs, as in previous studies of the magnification bias. Moreover, we were able to estimate the lensing convergence, κ(θ), for our magnification bias measurements down to a few kpcs. The derived mass density profile is in good agreement with a Navarro-Frank-White (NFW) profile. We also attempt an estimation of the halo mass and the concentration parameters, obtaining MNFW=1.0+0.4−0.2×1014 M⊙ and C=3.5−0.3+0.5. This concentration value is rather low and it would indicate that the cluster halos around these QSOs are unrelaxed. However, higher concentration values still provides a compatible fit to the data.
A Realistic Roadmap to Formation Flying Space Interferometry

The ultimate astronomical observatory would be a formation flying interferometer in space, immune to atmospheric turbulence and absorption, free from atmospheric and telescope thermal emission, and reconfigurable to adjust baselines according to the required angular resolution. Imagine the near/mid-infrared sensitivity of the JWST and the far-IR sensitivity of Herschel but with ALMA-level angular resolution, or imagine having the precision control to null host star light across 250m baselines and to detect molecules from the atmospheres of nearby exo-Earths. With no practical engineering limit to the formation's size or number of telescopes in the array, formation flying interferometry will revolutionize astronomy and this White Paper makes the case that it is now time to accelerate investments in this technological area. Here we provide a brief overview of the required technologies needed to allow light to be collected and interfered using separate spacecrafts. We emphasize the emerging role of inexpensive smallSat projects and the excitement for the LISA Gravitational Wave Interferometer to push development of the required engineering building-blocks. We urge the Astro2020 Decadal Survey Committee to highlight the need for a small-scale formation flying space interferometer project to demonstrate end-to-end competency with a timeline for first stellar fringes by the end of the decade.
On the nature of the resonant drag instability of dust streaming in protoplanetary disc

The recently discovered resonant drag instability (RDI) of dust streaming in protoplanetary disc is considered as the mode coupling of subsonic gas-dust mixture perturbations. This mode coupling is coalescence of two modes with nearly equal phase velocities: inertial wave (IW) having positive energy and a streaming dust wave (SDW) having negative energy as measured in the frame of gas environment being at rest in vertical hydrostatic equilibrium. SDW is a trivial mode produced by the bulk streaming of dust, which transports perturbations of dust density. In this way, settling combined with radial drift of the dust makes possible coupling of SDW with IW and the onset of the instability. In accordance with the concept of the mode coupling, RDI growth rate is proportional to the square root of the coupling term of the dispersion equation, which itself is proportional to mass fraction of dust, f ≪ 1. This clarifies why RDI growth rate ∝f1/2. When SDW has positive energy, its resonance with IW provides an avoided crossing instead of the mode coupling. In the high wavenumber limit RDI with unbounded growth rate ∝f1/3 is explained by the triple mode coupling, which is coupling of SDW with two IW. It coexists with a new quasi-resonant instability accompanied by bonding of two oppositely propagating low-frequency IW. The mode coupling does not exist for dust streaming only radially in a disc. In this case RDI is provided by the obscured mechanism associated with the inertia of solids.