cssi/SciSciGPT-SciSciNet huggingface dataset:
Application of finite mixture models for vehicle crash data analysis

Developing sound or reliable statistical models for analyzing motor vehicle crashes is very important in highway safety studies. However, a significant difficulty associated with the model development is related to the fact that crash data often exhibit over-dispersion. Sources of dispersion can be varied and are usually unknown to the transportation analysts. These sources could potentially affect the development of negative binomial (NB) regression models, which are often the model of choice in highway safety. To help in this endeavor, this paper documents an alternative formulation that could be used for capturing heterogeneity in crash count models through the use of finite mixture regression models. The finite mixtures of Poisson or NB regression models are especially useful where count data were drawn from heterogeneous populations. These models can help determine sub-populations or groups in the data among others. To evaluate these models, Poisson and NB mixture models were estimated using data collected in Toronto, Ontario. These models were compared to standard NB regression model estimated using the same data. The results of this study show that the dataset seemed to be generated from two distinct sub-populations, each having different regression coefficients and degrees of over-dispersion. Although over-dispersion in crash data can be dealt with in a variety of ways, the mixture model can help provide the nature of the over-dispersion in the data. It is therefore recommended that transportation safety analysts use this type of model before the traditional NB model, especially when the data are suspected to belong to different groups.
Efficient segmentation-based motion compensation for low-bit-rate video coding

In this paper, we investigate the performance of a segmentation-based motion compensation algorithm for videoconferencing which uses the motion information obtained from a set of analog position sensors. The position sensors provide high resolution motion information which is used to perform an affine transformation-based motion compensation. The simulation results are presented in the form of displaced frame difference (DFD) variance improvement versus the usual block matching algorithm. The proposed algorithm has the following advantages: (1) a very small amount of motion information needs to be transmitted, (2) the error energy is concentrated mainly in the boundary regions which makes it less noticeable, (3) different regions of the frame can be transmitted with different quality, and (4) a smaller computational load than advanced techniques is required.© (1996) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
THE COSMIC-RAY INTENSITY NEAR THE ARCHEAN EARTH

We employ three-dimensional state-of-the-art magnetohydrodynamic models of the early solar wind and heliosphere and a two-dimensional model for cosmic-ray transport to investigate the cosmic-ray spectrum and flux near the Archean Earth. We assess how sensitive the cosmic-ray spectrum is to changes in the sunspot placement and magnetic field strength, the large-scale dipole magnetic field strength, the wind ram pressure, and the Sun's rotation period. Overall, our results confirm earlier work that suggested the Archean Earth would have experienced a greatly reduced cosmic-ray flux than is the case today. The cosmic-ray reduction for the early Sun is mainly due to the shorter solar rotation period and tighter winding of the Parker spiral, and to the different surface distribution of the more active solar magnetic field. These effects lead to a global reduction of the cosmic-ray flux at 1 AU by up to two orders of magnitude or more. Variations in the sunspot magnetic field have more effect on the flux than variations in the dipole field component. The wind ram pressure affects the cosmic-ray flux through its influence on the size of the heliosphere via the pressure balance with the ambient interstellar medium. Variations in the interstellar medium pressure experienced by the solar system in orbit through the Galaxy could lead to order of magnitude changes in the cosmic-ray flux at Earth on timescales of a few million years.
Optimal unemployment insurance in an estimated job search model with savings

Abstract This paper estimates a job search model with savings on Danish micro data that include observations on wealth and wages. Controlling for extensive observed and unobserved worker characteristics heterogeneity, the estimation relates observed unemployment spells to the model implied hazard rate for each worker. The model estimates are sensible and fit the data well. Optimal UI policy is determined in the estimated model as a trade-off between insurance provision and distortion of search incentives. The analysis emphasizes an important policy sensitivity to the interest rate and the importance of including transitional dynamics in the analysis.
From information to learning commons: Campus planning highlights

Purpose – This paper seeks to highlight elements of and assumptions for an inclusive planning process which guided the transformation of an information commons into a learning commons over a six‐year period. It aims to present case study within the context of the North American higher education environment, in which this example illustrates the shift from a teaching to a learning orientation.Design/methodology/approach – The report illustrates the efficacy of a highly participatory and inclusive planning process which integrates ideas generated by campus stakeholders and beneficiaries – students, professors, and administrators – to redirect campus library activities from service to learning outcomes. The culminating Science Cafe example suggests the potential of repurposing space, revitalizing relationships, and re‐energizing programming within an academic library.Findings – The case study illustrates the impact of participatory (re)design of library priorities. It demonstrates the new insights produced t...
On the invariant theory for tame tilted algebras

We show that a tilted algebra A is tame if and only if for each generic root d of A and each indecomposable irreducible component C of mod(A,d), the field of rational invariants k(C) is isomorphic to k or k(x). Next, we show that the tame tilted algebras are precisely those tilted algebrasAwith the property that for each generic root d of A and each indecomposable irreducible component C ⊆ mod(A,d), the moduli space M(C) θ is either a point or just P whenever θ is an integral weight for whichC θ 6= ∅. We furthermore show that the tameness of a tilted algebra is equivalent to the moduli space M(C) θ being smooth for each generic root d of A, each indecomposable irreducible component C ⊆ mod(A,d), and each integral weight θ for which C θ 6= ∅. As a consequence of this latter description, we show that the smoothness of the various moduli spaces of modules for a strongly simply connected algebra A implies the tameness of A. Along the way, we explain how moduli spaces of modules for finite-dimensional algebras behave with respect to tilting functors, and to theta-stable decompositions.
A formality theorem for Hochschild chains

Abstract We prove Tsygan's formality conjecture for Hochschild chains of the algebra of functions on an arbitrary smooth manifold M using the Fedosov resolutions proposed in math.QA/0307212 and the formality quasi-isomorphism for Hochschild chains of R [ [ y 1 ,..., y d ] ] proposed in paper math.QA/0010321 by Shoikhet. This result allows us to describe traces on the quantum algebra of functions on an arbitrary Poisson manifold.
The Pendulum in the 21st Century-Relic or Trendsetter

When identifying instruments that have had great influence on the history of physics, none comes to mind more quickly than the pendulum. Though first treated scientifically by Galileo in the 16th century, and in some respects nearly ‘dead’ by the middle of the 20th century; the pendulum experienced ‘rebirth’ by becoming an archetype of chaos.With the resulting acclaim for its surprising behavior at large amplitudes, one might expect that there would already be widespread interest in another of its significant nonlinearities. Such is not the case, however, and the complex motions of small amplitude physical pendula are barely known. The present paper shows that a simply-constructed metallic rod pendulum is capable of demonstrating rich physics in a largely unstudied area.
The Circumstellar Disk of HD 141569 Imaged with NICMOS

Coronagraphic imaging with the Near-Infrared Camera and Multiobject Spectrometer on the Hubble Space Telescope reveals a large, ~400 AU (4'') radius, circumstellar disk around the Herbig Ae/Be star HD 141569. A reflected light image at 1.1 μm shows the disk oriented at a position angle of 356° ± 5° and inclined to our line of sight by 51° ± 3°; the intrinsic scattering function of the dust in the disk makes the side inclined toward us, the eastern side, brighter. The disk flux density peaks 185 AU (185) from the star and falls off to both larger and smaller radii. A region of depleted material, or a gap, in the disk is centered 250 AU from the star. The dynamical effect of one or more planets may be necessary to explain this morphology.
N-heterocyclic carbene-catalyzed rearrangements of vinyl sulfones

N-heterocyclic carbenes catalyze the rearrangement of 1,1-bis(arylsulfonyl)ethylene to the corresponding trans-1,2-bis(phenylsulfonyl) under mild conditions. Tandem rearrangement/cycloadditions have been developed to capitalize on this new process and generate highly substituted isoxazolines and additional heterocyclic compounds. Preliminary mechanistic studies support a new conjugate addition/Umpolung process involving the ejection and subsequent unusual re-addition of a sulfinate ion.
Focused video estimation from defocused video sequences

This paper proposes a novel technique for estimating focused video frames captured by an out-of-focus moving camera. It relies on the idea of Depth from Defocus (DFD), however overcomes the shortage of DFD by reforming the problem in a computer vision framework. It introduces a moving-camera scenario and explores the relationship between the camera motion and the resulting blur characteristics in captured images. This knowledge leads to a successful blur estimation and focused image estimation. The performance of this algorithm is demonstrated through error analysis and computer simulated experiments.
The Detailed Evolution of E+A Galaxies into Early Types

Poststarburst, or E+A, galaxies are the best candidates for galaxies in transition from being gas-rich and star- forming to gas-poor and passively evolving as a result of galaxy-galaxy interactions. To focus on what E+A galaxies become after their young stellar populations fade away, we present the detailed morphologies of 21 E+A galaxies using high-resolution HSTACS and WFPC2 images. Most of these galaxies lie in the field, well outside of rich clus- ters, and at least 55 (15%) have dramatic tidal features indicative of mergers. Our sample includes one binary E+A system, in which both E+As are tidally disturbed and interacting with each other. Our E+As are similar to early types inthattheyhavelargebulgeYtoYtotallightratios(medianB/T ¼ 0:59),highSersicindices(nk4),andhighconcen- trationindices(Ck4:3),buttheyhaveconsiderablylargerasymmetry indices(Ak0:04)thanellipticals,presumably due to the disturbances within a fewre caused by the starburst and/or the galaxy-galaxy interaction. We conclude that E+Aswillbemorphologicallyclassifiedasearly-typegalaxiesoncethesedisturbancesandthelowsurfacebrightness tidal features fade. The color morphologies are diverse, including six E+As with compact (0.4Y1.4 kpc) blue cores, which might be local analogs of high-z ellipticals with blue cores. The large fraction (70%) of E+As with positive colorgradientsindicatesthattheyoungstellarpopulationsaremoreconcentratedthantheold.Thesepositivecolor gradients (i.e., bluer nuclei) could evolve into the negative gradients typical in E/S0s if the central parts of these galaxies are metal-enhanced. Our E+As stand apart from the E/S0s in the edge-on projection of the fundamental plane (FP), implying that their stellar populations differ from those of E/S0s and that E+As have, on average, a M/L that is 3.8 times smaller. The tilt of the E+A FP indicates that the variation among their stellar populations is closely tied to the structural parameters; i.e., E+As follow their own scaling relationships such that smaller or less massive galaxies have smaller M/L. Wefind a population of unresolved compact sources in nineE+As (45%), all of which havemerger signatures. In the four E+As with suitable color data, the compact sources have colors and luminosities consistent with newly formed star clusters. The bright end of the cluster LF is fainter in redder E+As, suggesting that the young star clusters fade or are disrupted as the merger remnant ages. In summary, the morphologies, color profiles, scaling relations, and cluster populations are all consistent with E+As evolving ultimately into early types, making the study of E+As critical to understanding the origin of the red sequence of galaxies. Subject headingg galaxies: evolution — galaxies: interactions — galaxies: starburst — galaxies: star clusters — galaxies: stellar content
Keck Spectroscopy of Objects with Lens-like Morphologies in the Hubble Deep Field* **

We present spectroscopy from the Keck telescope of three sets of objects in the Hubble Deep Field (HDF) that have lens-like morphologies. In the case of J123641+621204, which is composed of four objects with similar colors and a mean separation of 08, we find at least two distinct components at redshifts of z = 3.209 and z = 3.220 that are separated by 05 spatially. Each of these components has narrow Lyα emission and possibly N V emission and Si IV and C IV in absorption or with a P Cygni profile. The second case is J123652+621227, which has an arclike feature offset by 18 to the southwest of a red elliptical-like galaxy and a "counterimage" offset 14 on the opposite side. We tentatively find a single line at 5301 A at the spatial position of the counterimage and no corresponding emission line at the position of the arc. The colors of the counterimage are consistent with the identification of this line as Lyα at z = 3.36. The colors of the arc are different than those of the counterimage, and thus both the colors and spectra indicate that this object is unlikely to be a gravitational lens. For a third lensing candidate (J123656+621221), which is a blue arc offset by 09 from a red, elliptical-like galaxy, our spectroscopy does not clearly resolve the system spatially, which complicates the interpretation of the spectrum. We discuss possible identifications of a number of absorption features and a very tentative detection of a pair of emission lines at 5650 A and 5664 A, and we find that gravitational lensing remains a possibility in this case. We conclude that the frequency of strong gravitational lensing by galaxies in the HDF appears to be very low. This result is difficult to reconcile with the introduction of a cosmological constant to account for the large number of faint blue galaxies via a large volume element at high redshift and tends to favor models in which very faint galaxies are at fairly modest redshifts.
Dimension reduction near periodic orbits of hybrid systems

When the Poincare map associated with a periodic orbit of a hybrid dynamical system has constant-rank iterates, we demonstrate the existence of a constant-dimensional invariant subsystem near the orbit which attracts all nearby trajectories in finite time. This result shows that the long-term behavior of a hybrid model with a large number of degrees-of-freedom may be governed by a low-dimensional smooth dynamical system. The appearance of such simplified models enables the translation of analytical tools from smooth systems—such as Floquet theory—to the hybrid setting and provides a bridge between the efforts of biologists and engineers studying legged locomotion.
Topology and Invertible Maps

I study connected manifolds and prove that a proper mapf:M?Mis globally invertible when it has a nonvanishing Jacobian and the fundamental group ?1(M) is finite. This includes finite and infinite dimensional manifolds. Reciprocally, if ?1(M) is infinite, there exist locally invertible maps that are not globally invertible. The results provide simple conditions for unique solutions to systems of simultaneous equations and for unique market equilibrium. Under standard desirability conditions, it is shown that a competitive market has a unique equilibrium if its reduced excess demand has a nonvanishing Jacobian. The applications are sharpest in markets with limited arbitrage and strictly convex preferences: a nonvanishing Jacobian ensures the existence of a unique equilibrium in finite or infinite dimensions, even when the excess demand is not defined for some prices, and with or without short sales.
Gluon production in current-nucleus and nucleon-nucleus collisions in a quasi-classical approximation

Abstract We calculate gluon production in deep inelastic scattering of the current j = − 1 4 F μν a F μν a off a large nucleus and in nucleon-nucleus collisions. In a covariant gauge calculation the transverse momentum spectrum of the gluon is determined by the final state interactions of the gluon with the nucleons in the nucleus. In a light-cone gauge calculation final state interactions are absent and these effects come from the light-cone wavefunction of the nucleus. We work in an approximation which neglects QCD evolution of gluons in the nucleon, that is in a quasi-classical approximation.
Modeling considerations for in-phase actuation of actuators bonded to shell structures

A closed-form model to represent the in-phase actuation of induced strain actuators bonded to the surface of a circular shell is developed. Because of the inherent shell curvature, the equivalent discrete tangential forces generally used to represent the in-phase actuation of the actuators (such as in pin-force models) are not colinear and result in the application of rigid body forces on the shell. This nonequilibrium state violates the principle of self-equilibrium of fully integrated structures, such as piezoelectrically actuated shells. The solution to this nonequilibrium problem is to apply a uniform transverse pressure over the actuator region to maintain equilibrium. Using this adequate equivalent loading scheme for in-phase actuation, a response model for a circular ring is derived based on shell governing equations. To verify the in-phase actuation response model, finite element analysis is performed. A perfect match between the in-phase actuation response model and the finite elements results, when the actuator mass and stiffness are neglected, validates the derived analytical model. If the self-equilibrium is not maintained (point-force model), the predicted deformed shape is completely different from the actual shell response to in-phase actuation. Thus, by simply applying a uniform transverse pressure along with the discrete tangential forces to maintain the self-equilibrium of the shell, the shell response can be modeled accurately.
Novel aspects of QCD in leptoproduction

I review several topics in electroproduction which test fundamental aspects of QCD. These include the role of final-state interactions in producing diffractive leptoproduction processes, the shadowing of nuclear structure functions, and target-spin asymmetries. The antishadowing of nuclear structure functions is shown to be quark-flavor specific, suggesting that some part of the anomalous NuTeV result for sin2θ W could be due to the non-universality of nuclear antishadowing for charged and neutral currents. I also discuss the physics of the heavy-quark sea, hidden color in nuclear wavefunctions, and evidence for color transparency for nuclear processes. The AdS/CFT correspondence connecting superstring theory to superconformal gauge theory has important implications for hadron phenomenology in the conformal limit, including an all-orders demonstration of counting rules for hard exclusive processes, as well as determining essential aspects of hadronic light-front wavefunctions.
Total synthesis of rutamycin B and oligomycin C.

The asymmetric synthesis of the macrolide antibiotics (+)-rutamycin B (1) and (+)-oligomycin C (2) is described. The approach relied on the synthesis and coupling of the individual spiroketal fragments 3a and 3b with the C1−C17 polyproprionate fragment 4. The preparation of the spiroketal fragments was achieved using chiral (E)-crotylsilane bond construction methodology, which allowed the introduction of the stereogenic centers prior to spiroketalization. The present work details the synthesis of the C19−C28 and C29−C34 subunits as well as their convergent assembly through an alkylation reaction of the lithiated N,N-dimethylhydrazones 6 and 8 to afford the individual linear spiroketal intermediates 5a and 5b, respectively. After functional group adjustment, these advanced intermediates were cyclized to their respective spiroketal-coupling partners 40 and 41. The requisite polypropionate fragment was assembled in a convergent manner using asymmetric crotylation methodology for the introduction of six of th...
Dynamical Electroweak Symmetry Breaking with a Heavy Fermion in Light of Recent LHC Results

The recent announcement of a discovery of a possible Higgs-like particle&#x2014;its spin and parity are yet to be determined&#x2014;at the LHC with a mass of 126&#x2009;GeV necessitates a fresh look at the nature of the electroweak symmetry breaking, in particular if this newly-discovered particle will turn out to have the quantum numbers of a Standard Model Higgs boson. Even if it were a 0
Experimental and Computational Results From the NASA Lewis Low-Speed Centrifugal Impeller at Design and Part-Flow Conditions

The NASA Lewis Low-Speed Centrifugal Compressor (LSCC) has been investigated with laser anemometry and computational analysis at two flow conditions: the design condition as well as a lower mass flow condition. Previously reported experimental and computational results at the design condition are in the literature (Hathaway et al., 1993). In that paper extensive analysis showed that inducer blade boundary layers are centrifuged outward and entrained into the tip clearance flow and hence contribute significantly to the throughflow wake. In this report results are presented for a lower mass flow condition along with further results from the design case. The data set contained herein consists of three-dimensional laser velocimeter results upstream, inside, and downstream of the impeller. In many locations data have been obtained in the blade and endwall boundary layers. The data are presented in the form of throughflow velocity contours as well as secondary flow vectors. The results reported herein illustrate the effects of flow rate on the development of the throughflow momentum wake as well as on the secondary flow. The computational results presented confirm the ability of modern computational tools to model the complex flow in a subsonic centrifugal compressor accurately. However, the blade tip shape andmore » tip clearance must be known in order to properly simulate the flow physics. In addition, the ability to predict changes in the throughflow wake, which is largely fed by the tip clearance flow, as the impeller is throttled should give designers much better confidence in using computational tools to improve impeller performance.« less
DOCUMENTATION OF SUBSIDIARY BODIES OF THE ECONOMIC AND SOCIAL COUNCIL

Abstract In this lecture the author describes the activities of the subsidiary bodies of the Economic and Social Council and the documentation these activities give rise to. Included in the discussion is the documentation of the standing committees, the functional commissions and the regional economic commissions.
Optimization of drift gases for accuracy in pressurized drift tubes

Abstract Modern detectors such as ATLAS use pressurized drift tubes to minimize diffusion and achieve high coordinate accuracy. However, the coordinate accuracy depends on the exact knowledge of converting measured times into coordinates. Linear space–time relationships are best for reconstruction, but difficult to achieve in the E ∝1/ r field. Previous mixtures, which contained methane or other organic quenchers, are disfavored because of ageing problems. From our studies of nitrogen and carbon dioxide, two mixtures with only small deviations from linearity were determined and measured. Scaling laws for different pressures and magnetic fields are also given.
Secular Changes in the Gender Composition of Employment and Growth Dynamics in the North and the South

Abstract In a simple theoretical exercise, the paper shows that gender relations matter in the standard analysis of trade liberalization and economic growth. It utilizes a model with the two differential equations, phase diagram technique which enables us to examine the cumulative interaction between economic growth and changes in the female share of employment. The model shows that changes in the gender composition of employment caused by a new global division of labor between the North and the South can thwart the economic benefits customarily associated with trade liberalization in both regions.
Smooth Robust Adaptive Sliding Mode Control of Manipulators With Guaranteed Transient Performance

A systematic way to combine adaptive control and sliding mode control (SMC) for trajectory tracking of robot manipulators in the presence of parametric uncertainties and uncertain nonlinearities is developed. Continuous sliding mode controllers without reaching transients and chattering problems are first developed by using a dynamic sliding mode. Transient performance is guaranteed and globally uniformly ultimately bounded (GUUB) stability is obtained. An adaptive scheme is also developed for comparison. With some modifications to the adaptation law, the control law is redesigned by combining the design methodologies of adaptive control and sliding mode control. The suggested controller preserves the advantages of both methods, namely, asymptotic stability of the adaptive system for parametric uncertainties and GUUB stability with guaranteed transient perfonnance of sliding mode control for both parametric uncertainties and uncertain nonlinearities. The control law is continuous and the chattering problem of sliding mode control is avoided. A prior knowledge of bounds on parametric uncertainties and uncertain nonlinearities is assumed. Experimental results conducted on the UCB/NSK SCARA direct drive robot show that the combined method reduces the final tracking error to more than half of the smoothed SMC laws for a payload uncertainty of 6 kg, and validate the advantage of introducing parameter adaptation in the smoothed SMC laws.
Simultaneous Measurements of Droplet Size and Transient Temperature Within Surface Water Droplets

A lifetime-based molecular tagging thermometry technique was developed for achieving simultaneous measurements of droplet size and transient temperature distribution within a small water droplet over a solid surface. For molecular tagging thermometry measurements, a pulsed laser is used to tag phosphorescent 1-BrNp · Mβ-CD ·ROH molecules premixed within a small water droplet Long-lived laser-induced phosphorescence is imaged at two successive times after the same laser excitation pulse. While the size of the water droplet (in terms of volume, height, contact area, and contact angle of the water droplet) can be determined instantaneously from the acquired phosphorescence images, the transient temperature measurement is achieved by taking advantage of the temperature dependence of phosphorescence lifetime, which is estimated from the intensity ratio of the acquired phosphorescence image pair. The feasibility and implementation of the lifetime-based molecular tagging thermometry technique were demonstrated by conducting simultaneous measurements of droplet size and spatially and temporally resolved temperature distribution inside a convectively-cooled microsized water droplet over an aluminum test plate to quantify the unsteady mass and heat transfer processes within the small water droplet to elucidate underlying physics to improve our understanding about microphysical phenomena associated with aircraft icing studies.
Additive effects in Ir–BICP catalyzed asymmetric hydrogenation of imines

Abstract Remarkable additive effects of imides and 1,3-indandione were found in an iridium–BICP catalyzed asymmetric hydrogenation of imines. The highest enantioselectivity of 95% ee has been obtained for the hydrogenation of 2,3,3-trimethylindolenine catalyzed by an Ir–BICP catalyst.
Deviation Angle Estimation for Axial-Flow Compressors Using Inviscid Flow Solutions

Development of a more satisfactory method of estimating deviation angles was attempted using analytical procedures. Solutions for inviscid, irrotational flow in the blade-to-blade plane were obtained with a finite-difference calculation method. Deviation angles for three cascades with rounded trailing edges were estimated using the inviscid flow solutions and four existing trailing edge hypotheses. The estimated deviation angles were compared with experimental values for a range of incidence angle and inlet flow angle. None of the hypotheses were satisfactory at all incidence angles for all the cascades considered. An alternative hypothesis is presented which is suitable for one of the cascade profiles over a range of incidence and blade setting angle.
Evaluation of Television Interference from High-Voltage Transmission Lines

The effects of different types of transmission-line noise on television reception are examined. Curves relating annoyance with measured signal-to- noise ratios are produced. Tolerability criteria are derived. Finally, the use of a TV set as noise detector for TVI measurements is introduced.
2MASS Observations of the Perseus, Orion A, Orion B, and Monoceros R2 Molecular Clouds

We use the 2MASS Second Incremental Release Point Source Catalog to investigate the spatial distribution of young stars in the Perseus, Orion A, Orion B, and MonR2 molecular clouds. After subtracting a semiempirical model of the field star contamination from the observed star counts, stellar surface density maps are used to identify compact clusters and any stellar population found more uniformly distributed over the molecular cloud. Each cloud contains between two and seven clusters, with at least half of the cluster population found in a single, rich cluster. In addition, a distributed stellar population is inferred in the Orion A and MonR2 molecular clouds within the uncertainties of the field star subtraction with a surface density between 0.013 and 0.083 arcmin-2. Sensitivity calculations suggest, however, that the number of stars in the distributed population may be underestimated by a factor of 2 or more if stars have been forming with a Miller-Scalo IMF at a constant star formation rate for longer than 10 Myr. After considering the possible evolutionary status of the distributed population, the global star formation efficiency implied by the sum of the distributed and cluster populations ranges between 1% and 9% among the four clouds. The fraction of the total stellar population contained in clusters for the nominal extinction model ranges from ≈50% to 100% if the distributed population is relatively young (<10 Myr), to ≈25%–70% if it is relatively old (≈100 Myr). The relatively high fraction of stars contained in clusters regardless of the age of the distributed population, in conjunction with the young ages generally inferred for embedded clusters in nearby molecular clouds, indicates that a substantial fraction of the total stellar population in these regions has formed within the past few million years in dense clusters. This suggests that either the star formation rate in each these clouds has recently peaked if one assumes clouds have ages greater than 10 Myr or molecular clouds are younger than typically thought if one assumes that the star formation rate has been approximately constant in time.
Perceptual learning solely induced by feedback.

Although feedback is considered to be an important factor in perceptual learning (PL), its role is normally considered limited to facilitation, rather than direct inducement, of PL. Recent studies, however, have suggested feedback to be more actively involved in the inducement of PL. The current study demonstrates an even more significant role for feedback in PL: feedback can evoke PL of a feature without any bottom-up processing of that feature. We use a “fake feedback” method, in which the feedback is related to an arbitrarily chosen feature, rather than actual performance. We find evidence of PL with this fake feedback method both when the learned feature is absent from the visual stimulus (Experiment 1) and when it conflicts with the visual stimulus (Experiment 2). We call this “feedback-based PL,” in contrast with the classical “exposure-based PL.” We find that feedback-based PL and exposure-based PL can occur independently of each other even while occurring in the same paradigm. These results suggest that feedback not only facilitates PL that is evoked by bottom-up information, but that it can directly induce PL, where such feedback-based PL occurs independently of exposure-based PL.
Recent Progress in Numerical Techniques for Flow Simulation

Recent developments in the use of numerical methods for fluid flow simulation show an increasing tendency to use numerical operators that can, in various ways, be factored. Use of methods having this property often increases the accuracy and efficiency of computer codes. Tracing the factorization property provides a unity to the basic concepts involved in the development of cyclic reduction, predictor-corrector, splitting, fast Fourier transform, and pseudospectral methods.-
Shape memory miscible blends for thermal mending

ABSTRACT We report on miscible blends comprised of linear-poly(0-caprolactone) (l-PCL) and chemically crosslinked network-PCL (n-PCL). The blends demonstrate unique Shape Memory Assisted Self-Healing (SMA SH) property, which is the materials ability to close local microscopic cracks and heal those cracks by bonding the crack surfaces. For Shape Memory (SM) characterization, temporary deformation of the networks was achieved at room temperature. Samples were temporarily fixed below their crystalline temperature (T c ) and shape recovery was triggered by a temperature above the blends melting temperature (T m ). Thermogravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC) were used to study the thermal properties of the blends and Dynamic Mechanical Analysis (DMA) and small-scale tensile testing were used to obtain the mechanical pr operties and self-healing efficiencies of the blends. Keywords: shape memory, self-healing, rebonding, crack healing 1. INTRODUCTION Shape Memory (SM) is the ability of certain classes of polymeric materials to temporarily fix a secondary, deformed shape and then recover the original, permanent shape upon application of a stimulus (usually by heating through a triggering temperature).
Top Quark Measurements

Ten years after its discovery at the Tevatron collider, we still know little about the top quark. Its large mass suggests it may play a key role in the mechanism of Electroweak Symmetry Breaking (EWSB), or open a window of sensitivity to new physics related to EWSB and preferentially coupled to it. To determine whether this is the case, precision measurements of top quark properties are necessary. The high statistics samples being collected by the Tevatron experiments during Run II start to incisively probe the top quark sector. This report summarizes the experimental status of the top quark, focusing in particular on the recent measurements from the Tevatron Run II.
Joint Spectrum and Power Allocation for Multi-Node Cooperative Wireless Systems

Energy efficiency is a growing concern for wireless networks, not only due to the emerging traffic demand from smart devices, but also because of the dependence on the traditional unsustainable energy and the overall environmental concerns. The urgent call for reducing power consumption while meeting system requirements has motivated increasing research efforts on green radio. In this paper, we investigate a new joint spectrum and power allocation scheme for a cooperative downlink multi-user system using the frequency division multiple access scheme, in which arbitrary $M$ base stations (BSs) coordinately allocate their resources to each user equipment (UE). With the assumption that multi-BS UE (user being served by multi-BS) would require the same amount of spectrum from these BSs, we conclude that when the number of multi-BS UEs is limited by $M-1$ , the resource allocation scheme can always guarantee the minimum overall transmit power consumption while meeting the throughput requirement of each UE and also each BS’s power constraint. Then, to decide the clusters of multi-BS UEs and the clusters of individual-BS UEs (users being served by individual BSs), we propose a UE-BS association scheme and a complexity reduction scheme. Finally, a novel joint spectrum and power allocation algorithm is proposed to minimize the total power consumption. Simulation results are presented to verify the optimality of the derived schemes.
Diffusion-induced bias in near-wall velocimetry

The Brownian fluctuations of the colloidal tracers often used in microscale velocimetry are typically isotropic in the bulk. In the near-wall region, however, these fluctuations are strongly affected by the hydrodynamic interaction with the wall and by the no-flux condition imposed by the wall. These wall effects can, under appropriate conditions, bias measurements based on colloidal tracers, potentially leading to significant overestimation of near-wall velocities. We use a Fokker–Planck description to generate probability density functions of the distances from a single wall sampled by the matched particles that are present in the same window at both the start and end of a time interval. The importance of the resulting bias for experimental parameters is then quantified in terms of the size of the imaged region and measurement interval. We conclude with a brief discussion of the implications for near-wall velocimetry measurements.
Counterexamples to Kauffman's conjectures on slice knots

Abstract In the late 1960s Jerome Levine classified the odd high-dimensional knot concordance groups in terms of a linking matrix associated to an arbitrary bounding manifold for the knot. His proof fails for classical knots in S 3 . Yet this philosophy has remained the only known strategy for understanding the classical knot concordance group. We show that this strategy is fundamentally flawed. Specifically, in 1982, in support of Levine's philosophy, Louis Kauffman conjectured that if a knot in S 3 is a slice knot then on any Seifert surface for that knot there exists a homologically essential simple closed curve of self-linking zero which is itself a slice knot, or at least has Arf invariant zero. Since that time, considerable evidence has been amassed in support of this conjecture. In particular, many invariants that obstruct a knot from being a slice knot have been explicitly expressed in terms of invariants of such curves on its Seifert surface. We give counterexamples to Kauffman's conjecture, that is, we exhibit (smoothly) slice knots that admit (unique minimal genus) Seifert surfaces on which every homologically essential simple closed curve of self-linking zero has non-zero Arf invariant and non-zero signatures.
International Collaborative Effort on Injury Statistics: 10 year review

International comparisons of injury data may be useful for examining differences in risk and for suggesting potential interventions or hypotheses for future studies. However important issues to be considered in conducting comparisons are related to both the underlying quality of the data and how the data are collected. The International Collaborative Effort (ICE) on Injury Statistics grew out of concerns over the comparability of international injury data. This article outlines the history behind the development of the Injury ICE, brief descriptions of current and past projects, collaborations, and reflections on the value of collaboration.
Characterization of brain plasticity in schizophrenia using template deformation.

Abnormal neurodevelopment may play a role in the pathophysiology of schizophrenia. We used Template Deformation Morphometry (TDM) to examine point-wise age-related changes in patients with schizophrenia compared with healthy brains. We used a set of skull-stripped brains from an image database of cranial MRIs. We then deformed a template image to the rest of the brains creating a set of deformations. Using the Jacobians of these deformations, we calculated the voxel-wise t-scores for comparison of controls with patients. We also calculated the voxel-wise Pearson correlation of Jacobian with age for both controls and patients. By examining the volume renderings of these statistical fields, we found that healthy people undergo age-related expansion of the ventricles and surrounding periventricular white matter. In contrast, patients show much less of this age-related expansion. We conclude that TDM demonstrates altered developmental course in the brains of patients with schizophrenia.
Large compressive preloads decrease lumbar motion segment flexibility

The bending, shear, and torsion flexibilities of 13 intact adult lumbar motion segments (from 11 men, two women, 48-83 years of age) were compared under three different compressive preloads, 0, 2,200, and 4,400 N. Test forces and moments up to 160 N and 16 Nm were applied at the center of the upper end plate of the intact disc. A compressive preload of 2,200 N resulted in a significant decrease in motion segment flexibilities in all seven test directions (p less than 0.06) when compared with results obtained with no preload; the preload decreased flexibility 2.6, 4.5, and 6.1 times in bending, axial torsion, and shear, respectively. These results suggest that studies of internal trunk load-sharing between active and passive tissues during strenuous tasks, which engender large spine compressive loads, should take these changes in spine passive resistance into consideration.
Multiple gamma lines from semi-annihilation

Hints in the Fermi data for a 130 GeV gamma line from the galactic center have ignited interest in potential gamma line signatures of dark matter. Explanations of this line based on dark matter annihilation face a parametric tension since they often rely on large enhancements of loop-suppressed cross sections. In this paper, we pursue an alternative possibility that dark matter gamma lines could arise from ''semi-annihilation'' among multiple dark sector states. The semi-annihilation reaction ψiψj → ψkγ with a single final state photon is typically enhanced relative to ordinary annihilation ψii → γγ into photon pairs. Semi-annihilation allows for a wide range of dark matter masses compared to the fixed mass value required by annihilation, opening the possibility to explain potential dark matter signatures at higher energies. The most striking prediction of semi-annihilation is the presence of multiple gamma lines, with as many as order N3 lines possible for N dark sector states, allowing for dark sector spectroscopy. A smoking gun signature arises in the simplest case of degenerate dark matter, where a strong semi-annihilation line at 130 GeV would be accompanied by a weaker annihilation line at 173 GeV. As a proof of principle, we construct two explicit models of dark matter semi-annihilation, one based on non-Abelian vector dark matter and the other based on retrofitting Rayleigh dark matter.
Variable-Length Compression Allowing Errors

This paper studies the fundamental limits of the minimum average length of lossless and lossy variable-length compression, allowing a nonzero error probability $\epsilon $ , for lossless compression. We give nonasymptotic bounds on the minimum average length in terms of Erokhin’s rate-distortion function and we use those bounds to obtain a Gaussian approximation on the speed of approach to the limit, which is quite accurate for all but small blocklengths: $ (1 - \epsilon ) k H(\mathsf S) - {({({k V(\mathsf S)}/{2 \pi })})}^{1/2} \mathop {\rm exp}[- ({( Q^{-1}\left ({\epsilon }\right ))^{2}}/{2})]$ , where $ Q^{-1}\left ({\cdot }\right )$ is the functional inverse of the standard Gaussian complementary cumulative distribution function, and $V(\mathsf S)$ is the source dispersion. A nonzero error probability thus not only reduces the asymptotically achievable rate by a factor of $1 - \epsilon $ , but this asymptotic limit is approached from below, i.e., larger source dispersions and shorter blocklengths are beneficial. Variable-length lossy compression under an excess distortion constraint is shown to exhibit similar properties.
First-principles study of electronic and structural properties of CuO

We investigate the electronic and structural properties of CuO, which shows significant deviations from the trends obeyed by other transition-metal monoxides. Using an extended Hubbard-based corrective functional, we uncover an orbitally ordered insulating ground state for the cubic phase of this material, which was expected but, to the best of our knowledge, was not found in the literature. This insulating state results from a fine balance between the tendency of Cu to complete its $d$-shell and Hund's rule magnetism. Starting from the ground state for the cubic phase, we also study tetragonal distortions of the unit cell (recently reported in experiments) and identify the equilibrium structure. Our calculations reveal an unexpected richness of possible magnetic and orbital orders, relatively close in energy to the ground state, whose stability depends on the sign and nature of distortion.
One-bit compressed sensing with non-Gaussian measurements☆

Abstract In one-bit compressed sensing, previous results state that sparse signals may be robustly recovered when the measurements are taken using Gaussian random vectors. In contrast to standard compressed sensing, these results are not extendable to natural non-Gaussian distributions without further assumptions, as can be demonstrated by simple counter-examples involving extremely sparse signals. We show that approximately sparse signals that are not extremely sparse can be accurately reconstructed from single-bit measurements sampled according to a sub-gaussian distribution, and the reconstruction comes as the solution to a convex program.