Miracle-dz/UniFAR-FTUs huggingface dataset:
Faint Galaxies in Deep Advanced Camera for Surveys Observations

We present the analysis of the faint galaxy population in the Advanced Camera for Surveys (ACS) Early Release Observation fields VV 29 (UGC 10214) and NGC 4676. These observations cover a total area of 26.3 arcmin2 and have depths close to that of the Hubble Deep Fields in the deepest part of the VV 29 image, with 10 σ detection limits for point sources of 27.8, 27.6, and 27.2 AB magnitudes in the gF475W, VF606W, and IF814W bands, respectively. Measuring the faint galaxy number count distribution is a difficult task, with different groups arriving at widely varying results even on the same data set. Here we attempt to thoroughly consider all aspects relevant for faint galaxy counting and photometry, developing methods that are based on public software and that are easily reproducible by other astronomers. Using simulations we determine the best SExtractor parameters for the detection of faint galaxies in deep Hubble Space Telescope observations, paying special attention to the issue of deblending, which significantly affects the normalization and shape of the number count distribution. We confirm, as claimed by Bernstein, Freedman, & Madore, that Kron-like magnitudes, such as the ones generated by SExtractor, can miss more than half of the light of faint galaxies, what dramatically affects the slope of the number counts. We show how to correct for this effect, which depends sensitively not only on the characteristics of the observations, but also on the choice of SExtractor parameters. We present catalogs for the VV 29 and NGC 4676 fields with photometry in the F475W, F606W, and F814W bands. We also show that combining the Bayesian software BPZ with superb ACS data and new spectral templates enables us to estimate reliable photometric redshifts for a significant fraction of galaxies with as few as three filters. After correcting for selection effects, we measure slopes of 0.32 ± 0.01 for 22 < gF475W < 28, 0.34 ± 0.01 for 22 < VF606W < 27.5, and 0.33 ± 0.01 for 22 < mF814W < 27. The counts do not flatten (except perhaps in the F475W filter), up to the depth of our observations. Our results agree well with those of Bernstein, Freedman, & Madore, who used different data sets and techniques, and show that it is possible to perform consistent measurements of galaxy number counts if the selection effects are properly considered. We find that the faint counts mAB > 25.5 can be well approximated in all our filters by a passive luminosity evolution model based on the COMBO-17 luminosity function (α = -1.5), with a strong merging rate following the prescription of Glazebrook et al., ϕ* ∝ (1 + Qz), with Q = 4.
A Numerical Method for Multiphase Incompressible Thermal Flows with Solid–Liquid and Liquid–Vapor Phase Transformations

ABSTRACT A numerical method for multiphase incompressible thermal flows with solid–liquid and liquid–vapor phase transformations is presented. The flow is mainly driven by thermocapillary force and vaporization. Based on the level set method and mixture continuum model, a set of governing equations valid for solid, liquid, and vapor phases is derived, considering phase boundary conditions as source terms in the transport equations. The vaporization process is treated as a source term in the continuity equation. The model developed is applied to the laser welding process, where the flow is coupled with optical phenomena. Formation and collapse of a laser-created hole is simulated.
Regulatory efforts to reduce dark trading in Canada and Australia: How have they worked?

Growth in dark trading has caused considerable concern among regulators and exchanges worldwide. These concerns recently prompted Canadian and Australian regulators to implement novel restrictions that require dark trades to provide meaningful price improvement relative to the best quotes at transparent exchanges. We examine the effects of these new rules. We find that in both Canada and Australia, the new rules substantially decreased the amount of dark trading; by one third of its previous level. As a consequence of tick sizes constraining the spread in most stocks, almost all dark trading post regulation occurs at the NBBO midpoint. The minimum price improvement requirements reduced broker internalization of client orders by making this practice less profitable. While these effects are largely consistent with the objectives of the regulation, we do not find evidence that the regulation achieved its higher-level objectives of improving market quality. We find no significant changes in the propensity to post lit liquidity. Furthermore, we find wider spreads in both countries post regulation in multivariate tests that exploit a control market. Our analysis reveals that the reason the regulation resulted in wider spreads is that it effectively replaced two-sided dark limit order markets with one-sided midpoint dark crossing systems in the large number of stocks that are constrained by the tick size. An implication of our findings is that minimum price improvement regulation is more likely to benefit liquidity if it is accompanied by reductions in tick sizes. JEL classification: G14, G18
On the Behavior of Turbulent Boundary Layers near Separation

Theme O NE of the most important problems in aerodynamics is the phenomenon of separation that defines the initiation of the wake. The location of separation can be determined analytically by virtue of the boundary-layer theory, even though this theory is not valid in the immediate neighborhood of separation. In most practical applications the boundary layers are turbulent along the largest portion of the solid boundaries and most often, in the vicinity of separation. A large number of methods have been developed to solve the turbulent boundary-layer equations with an appropriate closure assumption, but a straightforward numerical integration in their differential form was attempted only in the late sixties. A number of such investigations is referenced in the accompanying engineering report of this paper. { For steady laminar and turbulent boundary-layer flow the location of separation is signaled by the vanishing of the wall shear. This criterion has been extensively used in laminar flows for both experimental and analytical investigations.2 However, for turbulent flow the use of simplified theoretical models has forced investigators to develop heuristic criteria based on approximate expressions that approach certain values in the neighborhood of separation. The present report reconsiders the problem of turbulent separation. The classical closure assumptions are restated and their applicability in the neighborhood of separation is discussed. Some typical features of the flow are checked against available experimental data and previous theoretical predictions. Further, the location of separation is calculated and the response of the boundary-layer equations in the neighborhood of separation is carefully investigated. The present effort is intended to be a step towards the generalization of the method to unsteady flow.
Spectrum of IC 2149 and Its Central Star

Although the asymmetric optical image of IC 2149 does not fall into any standard morphologies (Balick et al. 1993), the overall shape and its radio frequency image show a bilateral symmetry. The central star of spectral class O7.5 is a remarkable object with a rich spectrum showing many Fe ions. We discuss this spectrum in detail. The nebula has been studied utilizing our theoretical photoionization models. Detailed analyses of spectral data are done in both the UV region (lambda less than 3000 A; IUE) and the optical region (3500 A approximately 10500 A; the Hamilton Echelle at Lick Observatory). The plasma diagnostics suggest an electron temperature of 9000 approximately 10,000 K and an electron density near 5600 cm. Our model calculations were carried out with due regard to the above plasma diagnostics. The observations can be interpreted by a model of IC 2149 which consists of two components (an equatorial ring and a polar cone), but the total emission is dominated by the relatively denser equatorial shell. Carbon, nitrogen, and oxygen appear to be depleted by a factor of about 3; ratios of other elements are also lower than in the Sun.
Stochastic User Equilibrium Formulation for Generalized Nested Logit Model

The route choice problem is complicated in typical transportation networks because of the size of the choice set and because of the overlapping problem since many routes share links. Well-known models like the probit and the logit were further developed in an attempt to overcome these problems. The logit model has the appeal of being relatively close to the probit model while keeping a convenient analytical closed form. However, the simple multinomial logit model cannot correctly represent route choice, especially with respect to the overlapping problem. Other hierarchical logit models can potentially overcome the overlapping problem. The recently developed generalized nested logit (GNL) model is found to be very suitable for route choice, as is the cross-nested logit (CNL) model. The inclusion of the congestion effect in the route choice problem is accounted for in stochastic user equilibrium (SUE) problems. The development of a SUE formulation for the GNL model is presented. In addition, how to adapt the GNL model to route choice in a way similar to that of the CNL model is shown. An equivalent SUE formulation for the GNL model is developed. In this way, a unified framework is presented to relate GNL-type models, which are derived from discrete choice theory, with aggregate entropy formulations. A preliminary algorithm is developed to illustrate the potential application of the GNL formulation for real networks.
A 3‐D finite element model for sound transmission through a double‐plate system with isotropic elastic porous materials

The prediction of sound transmission through multilayer structures is of utmost importance in aircrafts, buildings, and other engineering applications. In view of optimizing the transmission loss, the finite element method is an interesting mean to model such structures since it permits one to account for complex structure geometries and to model accurately the boundary conditions. In this paper, a 3‐D‐finite element model is developed to evaluate the normal incidence transmission loss through a double‐plate system with cavity absorption. The cavity is filled with an air‐saturated isotropic elastic porous materials. The model uses a two‐field finite element procedure for the porous medium based on the Biot theory. Since the Biot theory considers only the energy dissipation due to the viscous effects, the frequency‐dependent bulk modulus of the air, worked out by Champoux and Allard [J. Appl. Phys. 70, 2182–2191 (1991)], is adopted to account for the energy dissipation due to thermal exchanges. Also, two s.
Flow Control of a Sharp-Edged Airfoil

An experimental study of active control of fully separated flow over a symmetrical circular-arc airfoil at high angles of attack was performed. The experiments were carried out in a low-speed, open-circuit wind tunnel with the airfoil at angles of attack from 10 to 40 deg. Low-power input, unsteady excitation was applied to the leading or trailing edge. The actuation was provided by the periodic oscillation of a 4% chord flap placed on the suction side of the airfoil and facing the sharp edge
Orthogonality of estimating functions and nuisance parameters

SUMMARY Cox & Reid (1987) proposed the technique of orthogonalizing parameters, to deal with the general problem of nuisance parameters, within fully parametric models. They obtained a large-sample approximation to the conditional likelihood. Along the same lines Davison (1988) studied generalized linear models. In the present paper we deal with the problem of nuisance parameters, within a semiparametric setup which includes the class of distributions associated with generalized linear models. The technique used is that of optimum orthogonal estimating functions (Godambe & Thompson, 1989). The results are related to those of Cox & Reid (1987).
ASYMPTOTIC UPPER BOUNDS FOR THE PROPORTION OF SIMPSON SUBDIVISIONS OF A 2 × 2 TABLE

A sample of size N is characterized by two attributes, A and B. Assume that the corresponding 2 × 2 table of counts is subdivided into n 2 × 2 subtables according to the levels of an arbitrary and unknown factor C. The first case of Simpson's Paradox (SP) occurs when A and B are negatively associated in the sample (i.e., in the original 2 × 2 table), but positively associated or independent within each level of C. The second case of SP can be defined similarly by interchanging the words “negatively” and “positively” in the previous sentence. We consider the proportion of subdivisions of the original 2 × 2 table into n 2 × 2 subtables such that SP occurs. In a recent paper by Hadjicostas [1], the case n = 2 is examined, and is proven that, as N increases without bound, the aforementioned proportion of Simpson subdivisions approaches a function of the odds ratio of a limiting form of the original 2 × 2 table. In this paper, the results are partially generalized for the cases n ≥ 3. If n = 3, the asymptotic least upper bound for the proportion of Simpson subdivisions is calculated exactly. For n = 4, simulation results show that the corresponding upper bound is of the order 10−4.
Sputtering of water ice surfaces and the production of extended neutral atmospheres

Plasma and UV photon bombardment of an icy object in the outer solar system can lead to ejection of atoms and molecules from the surface which can, in turn, produce an extended neutral atmosphere. We present new laboratory studies of the sputtering of water ice by keV ions (H+ through Ne+) made using a sensitive microbalance technique that allows measurements at very low ion fluences. These results for the sputtering yield of ice by keV O+ ions, the dominant sputtering agents in the Saturnian magnetosphere, are much larger than those used previously to model the neutral cloud associated with the icy satellites. The data presented are used to recalculate previously published sputtering rates for the icy satellites of Jupiter and Saturn, and for the E-ring grains at Saturn. The new results can account, in part, for the discrepancy between the predicted and observed OH cloud near Tethys in Saturn's inner magnetosphere. We compare the yields induced by the incident ions to the recently measured UV photosputtering yield, and discuss possible synergism between UV photon and plasma ion induced erosion.
(1 + 1 + 2)-Generated Equivalence Lattices

Abstract Strietz [Proceedings of the Lattice Theory Conference, Ulm, 1975, pp. 257–259; Studia Sci. Math. Hungar.12 (1977), 1–17] and Zadori [Colloq. Math. Soc. Janos Bolyai43, “Lectures in Universal Algebra, Proceedings of the Conference, Szeged, 1983,” North-Holland, Amsterdam/New York, 1986, pp. 573–586] have shown that Equ(A), the lattice of all equivalences of a finite set A with |A| ≥ 7, has a four-element generating set such that exactly two of the generators are comparable. In other words, these lattices are (1 + 1 + 2)-generated. We extend this result for many infinite sets A; even for all sets if there are no inaccessible cardinals. Namely, we prove that if A is a set consisting of at least seven elements and there is no inaccessible cardinal ≤ |A|, then the complete lattice Equ(A) is (1 + 1 + 2)-generated. This result is sharp in the sense that Equ(A) has neither a three-element generating set nor a four-element generating set with more than one pair of comparable generators.
The drag on an undulating surface induced by the flow of a turbulent boundary layer

We investigate, using theoretical and computational techniques, the processes that lead to the drag force on a rigid surface that has two—dimensional undulations of length L and height H (with H/L [Lt ] 1) caused by the flow of a turbulent boundary layer of thickness h. The recent asymptotic analyses of Sykes (1980) and Hunt, Leibovich & Richards (1988) of the linear changes induced in a turbulent boundary layer that flows over an undulating surface are extended in order to calculate the leading-order contribution to the drag. It is assumed that L is much less than the natural lengthscale h* = hU0/u* over which the boundary layer evolves (u* is the unperturbed friction velocity and U0 a mean velocity scale in the approach flow). At leading order, the perturbation to the drag force caused by the undulations arises from a pressure asymmetry at the surface that is produced by the thickening of the perturbed boundary layer in the lee of the undulation. This we term non-separated sheltering to distinguish it from the mechanism proposed by Jeffreys (1925). Order of magnitude estimates are derived for the other mechanisms that contribute to the drag; the next largest is shown to be smaller than the non-separated sheltering effect by O(u*/U0). The theoretical value of the drag induced by the non-separated sheltering effect is in good agreement with both the values obtained by numerical integration of the nonlinear equations with a second-order-closure model and experiments. Although the analytical solution is developed using the mixing-length model for the Reynolds stresses, this model is used only in the inner region, where the perturbation shear stress has a significant effect on the mean flow. The analytical perturbation shear stresses are approximately equal to the results from a higher-order closure model, except where there is strong acceleration or deceleration. The asymptotic theory and the results obtained using the numerical model show that the perturbations to the Reynolds stresses in the outer region do not directly contribute a significant part of the drag. This explains why several previous analyses and computations that use the mixing-length model inappropriately throughout the flow lead to values of the drag force that are too large by up to 100%.
Minimum weight design of non‐linear elastic structures with multimodal buckling constraints

It well known that multimodal instability is an event particularly relevant in structural optimization. Here, in the context of non‐linear stability theory, an exact method is developed for minimum weight design of elastic structures with multimodal buckling constraints. Given an initial design, the method generates a sequence of improved designs by determining a sequence of critical equilibrium points related to decreasing values of the structural weight. Multimodal buckling constraints are imposed without repeatedly solving an eigenvalue problem, and the difficulties related to the non‐differentiability in the common sense of state variables in multimodal critical states, are overcome by means of the Lagrange multiplier method. Further constraints impose that only the first critical equilibrium states (local maxima or bifurcation points) on the initial equilibrium path of the actual designs are taken into account. Copyright © 2002 John Wiley & Sons, Ltd.
Io's gravity field and interior structure

Radio Doppler data generated by the Deep Space Network (DSN) from four encounters of the Galileo spacecraft with Io, Jupiter's innermost Galilean satellite, are used to infer Io's gravitational quadrupole moments. By combining the four flybys into a single solution for the gravity field, the response of Io to the second degree tidal and rotational potentials is accurately determined. This is characterized by the value of the second degree potential Love number k 2 = 1.2924 ± 0.0027. We construct interior models that satisfy constraints imposed by the mean radius R = 1821.6 ± 0.5 km, the mean density p = 3527.8 ± 2.9 kg/m 3 , and the normalized axial moment of inertia C/M R 2 = 0.37685 ± 0.00035. The gravitationally derived figure of Io has principal axes (c < b < a) a = 1830.0 ± 0.5 km, b = 1819.2 ± 0.5 km, and c = 1815.6 ± 0.5 km, consistent with the shape determined by imaging. Gravitational and other data strongly suggest that Io is in hydrostatic equilibrium. In this case, models of Io's interior density show that Io almost certainly has a metallic core with a radius between 550 and 900 km for an Fe-FeS core or between 350 and 650 km for an Fe core. Io is also likely to have a crust and a partially molten asthenosphere, but their thicknesses cannot be separately or uniquely determined from the gravitational data.
On the Nucleation of Ice in Highly Supersaturated Regions of Clouds

Abstract We simply but quantitatively analyze the hypothesis that the common observation, that ice crystal concentrations in clouds often far exceed measured ice nucleus concentrations, can be explained by our inability to reproduce cloud supersaturations during laboratory measurements of ice nuclei together with the fact that the probability of ice nucleation increases with supersaturation. We find the general hypothesis, while qualitatively appealing, is quantitatively unlikely. Especially unlikely is the particular hypothesis that the extremely high supersaturation regions that form around freezing drops contribute significantly to ice in clouds. The reasons for this are twofold: 1) the drop also warms the region of high supersaturation and 2) the region is very small compared to the regions of cloud with high ice concentrations.
A consistent co‐rotational formulation for shells using the constant stress/constant moment triangle

The facet-shell formulation involves the combination of the constant-strain membrane triangle with a constant-curvature bending triangle. The paper describes a technique whereby this facet-formulation is extended to handle geometric non-linearity by means of a co-rotational procedure. Emphasis is placed on the derivation of a technique that is increment-independent with both the internal force vector and tangent stiffness matrix being derived from the «total strain measures» in a «consistent manner».
Pedestrian Attribute Recognition Based on Multi-Scale Feature Fusion Over a Larger Receptive Field and Strip Pooling

Pedestrian attribute recognition is a vital task in computer vision, which is widely used in pedestrian detection and pedestrian re-identification, etc. Pedestrian attribute recognition aims to excavate the attributes of the target person from video or images. To solve the specific challenging factors in this task, such as changes in viewpoint, lacking illumination, and low resolution, we propose a brand new pedestrian attribute recognition method. Using ASPP to extend the receptive fields and densely connect the generated features, multi-scale feature fusion merges features from different receptive fields into one feature that is more discriminative than the input features. And the AIIM module is used to establish remote dependencies at different spatial scales. Extensive experiments show that our proposed method achieves state-of-the-art results with average accuracy (mA) of 86.35%, 81.60%, and 83.29% on public datasets such as PETA, PA100k, and RAP, respectively.