Miracle-dz/UniFAR-FTUs huggingface dataset:
Instrumental variable estimation of nonparametric models

In econometrics there are many occasions where knowledge of the structural relationship among dependent variables is required to answer questions of interest. This paper gives identification and estimation results for nonparametric conditional moment restrictions. We characterize identification of structural functions as completeness of certain conditional distributions, and give sufficient identification conditions for exponential families and discrete variables. We also give a consistent, nonparametric estimator of the structural function. The estimator is nonparametric two-stage least squares based on series approximation, which overcomes an ill-posed inverse problem by placing bounds on integrals of higher-order derivatives. Copyright The Econometric Society 2003.
Weight distributions: how deviant can you be?

We investigate the asymptotic weight distribution of LDPC (low density parity check) code ensembles. We show that two cases, namely, linear and logarithmic growth of the minimum distance can be distinguished, depending on the degree distribution pair. Furthermore, combining this result with Shokrollahi's (2000) flatness condition, we get the surprising conclusion: if we want to achieve capacity, we cannot have large minimum distance!
Input of long- and middle-wavelength-sensitive cones to orientation discrimination

Orientation discrimination thresholds for Gabor stimuli as a function of spatial frequency [0.6, 1, 2, or 4 cycles per degree (cpd)] and contrast were determined for several directions in the color plane spanned by the long-wavelength-sensitive (L) and medium-wavelength-sensitive (M) cones. For Gabor stimuli with carrier frequencies of 2 or 4 cpd we do not find a systematic and robust advantage of a particular color direction in the LM-cone plane when the stimuli are equated in terms of the sum of the absolute L- and M-cone contrasts. Luminance (L+M) and equiluminant (L–2M) stimuli of identical overall L- and M-cone contrast yield identical orientation discrimination thresholds for the 2-cpd stimuli for the entire available contrast range (1–11%). For the very-low-spatial-frequency stimuli, orientation discrimination thresholds are lower for equiluminant stimuli than for luminance stimuli of the same cone contrast; for 4 cpd, orientation discrimination thresholds are slightly higher for equiluminant red–green stimuli than for luminance-defined stimuli.
Theory of spin-polarised inhomogeneous relativistic electron systems. II

A critical comparison of the authors earlier theory with a recent alternative theory of MacDonald (see ibid., vol.16, p.3896, 1983) is given. After correcting some errors in the previous work, new analytical results are presented here. Most importantly, it is pointed out that the authors theory is renormalisable and relativistically invariant in contrast to MacDonald's theory. His results for the leading-order relativistic parameter are the same as the authors present results since he did not use his theory in this regime. The physical picture associated with the theory of spin polarisation in a relativistic theory is spelled out in greater detail than before. It is found that the total exchange energy and the exchange potential change sign for different sets of values of the relativistic and magnetisation parameters.
The dissipation of kinetic energy in the lowest layers of the atmosphere

The supply of kinetic energy to a shallow layer of air is considered. The cases chosen for analysis comprise occasions of comparatively strong wind and of fairly small temperature gradient so that the supply of kinetic energy from the vertical flux of total heat is not important at small heights. In these cases the diffusive flux of kinetic energy is also shown to be negligible. Hence it follows that, on these occasions, the rate of dissipation per unit volume is given by the product of the local values of the shearing stress and vertical gradient of mean velocity when steadiness and horizontal uniformity of the turbulence are assumed. Estimates of the rate of dissipation per unit mass at heights from 1 m to 50 m are made for particular occasions and used, together with the observed energy densities, to provide estimates of the size of the dissipating eddies at the heights of observation according to expressions given by L. F. Richardson and G. I. Taylor.
On shock impedance

The objective of the paper is to formulate a physically realistic definition of shock impedance. The definition obtained, expression (15), is consistent with the acoustic limit, with the Polachek & Seeger result for head-on shock incidence, and with the various reflexion limits. It seems to be applicable to all known regular and irregular refractions, with the possible exception of a refraction containing a Guderley patch. It is shown that one result of increasing impedance mismatch is to produce precursor and postcursor waves. It is thought the impedance mismatch caused by the jets of supersonic aircraft might be used to reduce the sonic boom overpressure.
Robust multi-level phase shift modulation in high-speed WDM transmission

In this paper, an overview of promising solutions for multi-level modulation formats, primarily based on phase shift keying (PSK), in optical WDM-transmission is presented and some recent results are summarized. With PSK modulation the option of multi-level signalling is offered which means that more than one bit is mapped on one transmitted symbol and thus offering bandwidth reduction for increased spectral efficiency. We investigate the performance with respect to receiver sensitivity, non-linear fibre impairments, chromatic and polarization mode dispersion. Last but not least the implementation-effort at high speed must comply with economic constraints.
Analyzing the impact of the inlet temperature on the acoustic noise production form a supersonic jet using large eddy simulations

Non-ideal expanded supersonic jets emerging from a convergent-divergent nozzle produce three different types of noise, i.e., the shock-associated broadband noise, the screech noise, and the turbulent mixing noise. Interesting to note that the screech tone outside of the nozzle was exposed mostly in downscaled laboratory experiments, while under realistic conditions the exhaust jet of a gas turbine engine does not show this phenomena. Apart from a geometric scaling difference, usually a lower temperature is employed in experimental studies. It is believed that the screech tone occurs due to self-excitation of the shear-layer in a feedback-loop. Acoustic waves generated by vortical structures interacting with a shock are propagating upstream within the subsonic region of the shear-layer or outside of it. They eventually hit the nozzle's lip and excite instabilities at a certain frequency. The compressible Navier-Stokes equations are simulated numerically by using Large Eddy Simulation approach. The effect o.
Anomalous Discharging Currents due to Space Charge

Discharging currents caused by the migration of space charge (e.g. due to electrons injected from the electrode) after removing an applied field were numerically calculated under various conditions. The calculated discharging currents flowed in the opposite direction to the charging current under the condition of ohmic electrodes, while the blocking electrodes resulted in the anomalous discharging currents flowing in the same direction as the charging current. The behaviors of the anomalous discharging currents are discussed in detail and they are in good agreement quantitatively with the experimental data obtained for high-density polyethylene. The temporal changes in the distributions of space charge and internal field, and the contribution of diffusion to the currents were also revealed.
Design and applications of a high-speed Doppler imaging vibrometer

We describe a unique high-speed Doppler imaging vibrometer configured for rapid full-field measurement of arbitrary solid body vibrations without temporal or spatial measurement multiplexing. The instrument design employs a staring 16×16 measurement beam matrix and passive fiber-optic focal plane array, remotely coupled to distributed parallel receivers and digital processors. High-speed data captured by the instrument indicate the rich dynamic complexity to be found even in comparatively simple coupled mechanical systems with transient features that are otherwise difficult to observe. The system provides a new tool for instantaneous non-contact full-field vibration measurement of structural dynamics, including, but not limited to, transient or non-repeatable phenomenon.
On the Weighted Local Time and the Tanaka Formula for the Multidimensional Fractional Brownian Motion

Abstract We determine the weighted local time for the multidimensional fractional Brownian motion from the occupation time formula. We also discuss on the Itô and Tanaka formula for the multidimensional fractional Brownian motion. In these formulas the Skorohod integral is applicable if the Hurst parameter of fractional Brownian motion is greater than 1/2. If the Hurst parameter is less than 1/2, then we use the Skorohod type integral introduced by Nualart and Zakai for the stochastic integral and establish the Itô and Tanaka formulas.
CCD SOFT X-RAY OBSERVATIONS OF THE PUPPIS A SUPERNOVA REMNANT

We present the first images and spectra of an astronomical object, other than the Sun, acquired with a charge coupled device (CCD) imaging X-ray spectrometer. During a 230 s sounding rocket observation, we have acquired moderate-resolution spectra and moderate-resolution images of a portion of the Pup A supernova remnant (SNR). Based on these data, we conclude that the X-ray spectrum of Pup A is inconsistent with any single-temperature equilibrium or nonequilibrium plasma model. We find evidence for variations in the emitting plasma on scales as small as 5.0 min and as large as 30.0 min. The spatial structure of the spectral variations in the remnant is found to be inconsistent with the standard Sedov model for the evolution of a SRN into a homogeneous interstellar medium (ISM). We suggest that the remnant is expanding into a region of the ISM having a density of approximately 1 cm(exp -3) with inhomogeneities on the order of 50%. We have found evidence for the presence of a knot of plasma enriched in neon, but require more data to be conclusive.
Nuclear magnetic resonance imaging of apparent slip effects in xanthan solutions

Nuclear magnetic resonance imaging has been used to investigate the flow of 0.2% aqueous solutions of xanthan gum. Apparent slip was observed in solutions made from the material supplied by UNAM but not in that supplied by Aldrich or Kelco. The apparent slip velocity was a constant fraction of the maximal velocity for a given contraction ratio. The apparent slip velocity also appeared to be independent of L/D but was strongly influenced by the wall stress, the observed apparent slip velocities being comparable with those determined using the Mooney analysis on capillary flows. After exposure to the action of a syringe pump, which reduced the mean molecular weight of the xanthan, the UNAM xanthan solution no longer exhibited apparent slip. Slip appears to be a function of molecular weight, possibly through sensitivity to the aspect ratio of the molecule.
Scaling, entanglement, and quantum phase transitions

In this paper we discuss the entanglement near a quantum phase transition by analyzing the properties of the concurrence for a class of exactly solvable models in one dimenion. Entanglement can be classified in the framework of the scaling theory of phase transition. There is a profound difference between the classical correlations, whose correlation length diverges at the phase transiton, and non-local quantum correlations that remain, in general, short ranged.
Analysis of operation mechanism of semi-insulating GaAs photoconductive semiconductor switches

This paper reports that the quenched-domain mode of luminous charge domain has been observed in semi-insulating (SI) GaAs photoconductive semiconductor switches (PCSSs) and the typical characteristics of lock-on effect have been explained based on the model of luminous charge domain. It is shown that the domain is formed by photogenerated carriers and the quenched domain is due to the interaction of the circuit self-excitation and transferred-electron oscillation in the bulk of switch. During the transit of the domain, the bias electric field (larger than Gunn threshold) across the switch is modulated by the ac electric field, when the instantaneous bias electric field is swinging below the sustaining field (the minimum electric field required to support the domain), and then the quenched-domain mode is obtained. When PCSSs operate in nonlinear mode, the ultrahigh electric field of domain induced by photogenerated carriers leads to strong impact ionization accompanied by electron-hole recombination radiat.
Inferring criteria's relative importance coefficients in PROMETHEE II

Most of decision aid models involve parameters that allow modelling the decision-maker's preferences. These parameters' values must be determined with the decision-maker's collaboration. Notably, this is the case for the criteria's relative importance coefficients (RICs). The determination of criteria's RICs represents an important task for the decision-maker, which is generally difficult to accomplish. The information provided at this level is unavoidably subjective and often partial, and then it should be well exploited. This is precisely the target of this paper, for the criteria's RICs of PROMETHEE method. We will use mathematical programming in order to develop a preference disaggregation approach. The programme built will contain multiple solutions, but will allow taking out intervals for the RICs' values. Hurwicz's criterion will permit us to explicit a value for each RIC.
The Use of Technology Acceptance Model to Explain Brand Attitude and Loyalty Intention in E-Commerce: The Gamification Case

Manuscript type: Research Article Research Aims: This paper analyzes the role of the Technology Acceptance Model (TAM), perceived enjoyment, perceived social influence, consumer intention to engage, and brand loyalty in the context of gamification in e-commerce. Design/methodology/approach: Online survey was conducted to collect data, and Partial Least Square (PLS) was used to analyze the effects among variables. Research Findings: The study found that perceived usefulness, perceived social influence, and perceived enjoyment had a positive effect on brand attitude, while perceived ease of use had an insignificant effect on brand attitude. The brand attitude was found to have a significant effect on loyalty intention. Theoretical Contribution/Originality: This research elaborated on the role of TAM in using the gamification method for intention to engage, brand attitude, and its effect on loyalty intention. Practitioner/Policy Implication: The company that applies gamification should develop a fun and interesting game to create engagement. Emotional bonding and a positive consumer feeling must be maintained to build consumer loyalty. Research limitation/Implications: The external factor such as subjective norm, design, image, job relevance, technology efficacy influence, the level of perceived usefulness, and ease of use. Keywords: Technology Acceptance Model (TAM), perceived enjoyment, perceived social influence, brand loyalty, gamification, e-commerce.
Culprit versus Complete Revascularization during the Initial Intervention in Patients with Acute Coronary Syndrome Using a Virtual Treatment Planning Tool: Results of a Single-Center Pilot Study

Background and Objectives: The revascularization strategy for percutaneous coronary intervention (PCI) in patients with multivessel (MV) acute coronary syndrome (ACS) remains controversial. Certain gaps in the evidence are related to the optimal timing of non-culprit lesion revascularization and the utility of instantaneous wave-free ratio (iFR) in the management of MV ACS intervention. The major benefits of iFR utilization in MV ACS patients in one-stage complete revascularization are: (1) the possibility to virtually plan the PCI, both the location and the extension of the necessary stenting to achieve the prespecified final hemodynamic result; (2) the opportunity to validate the final hemodynamic result of the PCI, both in culprit artery and all non-culprit arteries and (3) the value of obliviating the uncomfortable, costly, time consuming and sometimes deleterious effects from Adenosine, as there is no requirement for administration. Thus, iFR use fosters the achievement of physiologically appropriate complete revascularization in MV ACS patients during acute hospitalization. Materials and Methods: This pilot study was aimed to test the feasibility of a randomized trial research protocol as well as to assess patient safety signals of co-registration iFR-guided one-stage complete revascularization compared with that of standard staged angiography-guided PCI in de novo patients with MV ACS. This was a single-center, prospective, randomized, open-label clinical trial consecutively screening patients with ACS for MV disease. The intervention strategy of interest was iFR-guided physiologically complete one-stage revascularization, in which the virtual PCI planning of non-culprit lesions and the intervention itself were performed in one stage directly following treatment of the culprit lesion and other critical stenosis of more than ninety percent. Seventeen patients were recruited and completed the 3-month follow-up. Results: Index PCI duration was significantly longer while the volume of contrast media delivered in index PCI was significantly greater in the iFR-guided group than in the angiography-guided group (119.4 ± 40.7 vs. 47 ± 15.5 min, p = 0.004; and 360 ± 97.9 vs. 192.5 ± 52.8 mL, p = 0.003). There were no significant differences in PCI-related major adverse cardiovascular events (MACE) between the groups during acute hospitalization and at 3-months follow-up. One-stage iFR-guided PCI requires fewer PCI attempts until complete revascularization than does angiography-guided staged PCI. Conclusions: Complete revascularization with the routine use of the virtual planning tool in one-stage iFR-guided PCI is a feasible practical strategy in an everyday Cath lab environment following the protocol designed for the study. No statistically significant safety signals were documented in the number of PCI related MACE during the 3-month follow-up.
Testability and Dependability of AI Hardware: Survey, Trends, Challenges, and Perspectives

Editor’s notes: Hardware realization of artificial intelligence (AI) requires new design styles and even underlying technologies than those used in traditional digital processors or logic circuits. Therefore, their dependability and testability requirements, challenges, and solutions are fundamentally different and unique. This survey article covers this very important topic and provides insight to such issues. —Mehdi Tahoori, Karlsruhe Institute of Technology
Electrical characteristics of lateral heterostructure organic field-effect bipolar transistors

We describe and discuss the unique electrical characteristics of an organic field-effect transistor in which the active layer consists of a type II lateral heterojunction located approximately midway between the source and drain. The two active semiconductors on either side of the junction transport only one carrier type each, with the other becoming trapped, which leads to devices that operate in only the steady state when there is balanced electron and hole injections from the drain and source. We describe the unique transfer characteristics of such devices in two material systems.
Can a Tablet Game That Boosts Kindergarten Phonics Advance 1st Grade Reading?

Abstract We report the effectiveness of using the tablet-game Kalulu Phonics immediately after intervention in kindergarten and on national evaluations the year after. In a previous intervention testing the software with 1st graders, fluency and comprehension were boosted, but only when used in concert with reading instruction at the start of the year. Here, we asked whether a similar intervention would be more efficient if it started a year earlier, in kindergarten. Forty classes (1092 = children) were randomized into playing Kalulu Phonics or the matched Kalulu Numbers control game for the first half of the year, with reversed assignments in the second half. Ten non-randomized business-as-usual classes also participated. In a cross-over effect, children who used the phonics version improved in letter naming, grapheme-phoneme correspondence (GPC) matching and fluency. Students with the number version improved in number knowledge. In a longitudinal follow-up, all intervention participants maintained an advantage in phoneme awareness and GPC matching at the start of 1st grade, but this advantage failed to translate into school literacy gains by mid-year. No longitudinal benefits were found for numbers. Our results support using tablet-based aids in spurring early reading skills but question the possibility that a short-term intervention may address the challenges of long-term educational goals.
Investigation of supplement products preferred by healthcare professionals during COVID-19 pandemic process

Objective: Various products are used to strengthen immunity in prevention and treatment during the COVID-19 pandemic affecting the whole world, which has no cure yet, and the vaccine has just been used. This study was planned to learn about the supplements used by healthcare professionals. Methods: A questionnaire was applied to the physicians, nurses, technicians, secretaries, and staff working in the operating room, intensive care, ward, and outpatient clinic by e-mail, WhatsApp, or face-to-face interview method. Results: There was no difference between the groups in terms of being COVID-19-positive. The most used products were primarily Mg and vitamin D, and vitamin C, ginger, Zn, turmeric, green tea, vitamin complex, thyme, black elderberry (sambucus nigra), propolis, prebiotic/probiotic, acetylsalicylic acid (ASA), black cumin (niger sativa), N-acetyl cysteine (NAC), selenium (Se), Coenzyme-Q10, cinnamon, glutathione (GSH) and quercetin respectively. No one had used alpha lipoic acid (ALA). The products that showed significant differences between the groups with and without COVID-19 were vitamin C, prebiotic/probiotic, propolis and ASA. Conclusıon: Since it is not asked when the product is used, although it is not possible to evaluate its effectiveness for preventive or therapeutic purposes, known to be natural, inexpensive, and easily accessible antiviral products may be preferred.
Predictions of a Film Coolant Jet in Crossflow With Different Turbulence Models

This study investigates the performance of several existing turbulence models for the prediction of film coolant jet in a crossflow. Two-equation models employing k-e and k-ω closures, broadly categorized as high-Reynolds-number formulations, low-Reynolds-number formulations, DNS-based formulation, and nonlinear formulations have been used to simulate the flow. In all, seven different turbulence models have been tested. Predictions with different models have been compared with experimental results of Ajersch et al. (1995) and with each other to critically evaluate model performance. The assessment of models has been done keeping in mind that all models have been formulated for wall-bounded flows and may not be well suited for the jet-in-a-crossflow situation. Close agreement with experimental results was obtained at the jet exit and far downstream of the jet injection region, but all models typically overpredicted the magnitude of the velocities in the wake region behind the jet. The present study clearly underscores the deficiencies of the current models, and demonstrates the need for improvements.