cssi/SciSciGPT-SciSciNet huggingface dataset:
Photographic Plates for the Extreme Ultra-Violet

IN recent years there have been a number of attempts to improve the photographic methods, perfected by Schumann, used in the investigation of the ultra-violet, so far without any very striking results.
Rendezvous Guidance Trajectories via Multiple-Subarc Sequential Gradient-Restoration Algorithm

We consider the three-dimensional rendezvous between a target spacecraft in a circular orbit and a chaser spacecraft with an initial separation distance and an initial separation velocity. We assume that the chaser spacecraft has variable mass and that its trajectory is governed by three controls, one determining the thrust magnitude and two determining the thrust direction. We employ the Clohessy–Wiltshire equations, describing the relative motion of the chaser vis-a-vis the target, and the multiple-subarc sequential gradient-restoration algorithm to produce first optimal trajectories and then guidance trajectories for the following problems: P1—minimum time, fuel free; P2—minimum fuel, time free; P3—minimum time, fuel given; P4—minimum fuel, time given; and P5—minimum time×fuel , time and fuel free. Clearly, P1 and P2 are basic problems, while P3, P4, and P5 are compromise problems. Problem P1 leads to a two-subarc solution including a max-thrust subarc followed by another max-thrust subarc. Problem P2 ...
Variable Step Random Walks and Self-Similar Distributions

We study a scenario under which variable step random walks give anomalous statistics. We begin by analyzing the Martingale Central Limit Theorem to find a sufficient condition for the limit distribution to be non-Gaussian. We study the case when the scaling index∼ζ is∼12. For corresponding continuous time processes, it is shown that the probability density function W(x;t) satisfies the Fokker–Planck equation. Possible forms for the diffusion coefficient are given, and related to W(x,t). Finally, we show how a time-series can be used to distinguish between these variable diffusion processes and Levy dynamics.
Energy losses in mixed matrix superconducting wires under fast pulsed conditions

Energy losses have been measured on a set of mixed matrix (CuNi, Cu, NbTi) superconducting wires at \dot{B} 's up to 1.5 × 107G/s. The losses have been measured as a function of wire diameter, twist pitch, maximum applied field, and \dot{B} . Both static and dynamic losses were measured for a field applied perpendicularly to the wire axis. The dynamic losses were measured by slowly applying an external field to a sample and then causing the field to decay exponentially in roughly 1 ms to 10 ms. Under low B (9 kG) and \dot{B} (106G/s) conditions the hysteretic loss dominated. At high B (21 kG) and \dot{B} (1.5 × 107G/s) the matrix losses became dominant. The systematic variation of the losses with the mentioned parameters will be presented and will be compared to theoretical predictions.
Detection of ultrafast thermal transients using a chirped, super-continuum white light pulse

Summary form only given. Ultrafast material transients are typically measured with a correlation technique that uses two ultrashort laser pulses and a delay line. The technique presented in this work encodes the temporal information onto the spectral components of a chirped and temporally stretched, super-continuum probe pulse. This preserves the information of the entire material transient onto a single probe pulse. The approach generalizes and improves on the single-shot, narrowband, chirped detection technique used by Z. Jiang and C. Zhang (1998). Other single shot techniques have been recently realized that separate a single probe pulse into a series of time-delayed probe pulses that are spatially separated onto a CCD device. The use of a continuous probe pulse such as the technique presented here offers several advantages including ease of configuring the time record length and temporal resolution while providing a degree of insensitivity to optical misalignment.
Collinear factorization for deep inelastic scattering structure functions at large Bjorken xB

We examine the uncertainty of perturbative QCD factorization for hadron structure functions in deep inelastic scattering at a large value of the Bjorken variable xB. We analyze the target mass correction to the structure functions by using the collinear factorization approach in the momentum space. We express the long distance physics of structure functions and the leading target mass corrections in terms of parton distribution functions with the standard operator definition. We compare our result with existing work on the target mass correction. We also discuss the impact of a final-state jet function on the extraction of parton distributions at large fractional momentum x.
Solution of matrix Riemann-Hilbert problems with quasi-permutation monodromy matrices

In this paper we solve an arbitrary matrix Riemann-Hilbert (inverse monodromy) problem with irreducible quasi-permutation monodromy representation outside of a divisor in the space of monodromy data. This divisor is characterized in terms of the theta-divisor on the Jacobi manifold of an auxiliary compact Riemann surface realized as an appropriate branched covering of P1 . The solution is given in terms of a generalization of Szego kernel on the Riemann surface. In particular, our construction provides a new class of solutions of the Schlesinger system. The isomonodromy tau-function of these solutions is computed up to a nowhere vanishing factor independent of the elements of monodromy matrices. Results of this work generalize the results of papers [13] and [14] where the 2× 2 case was solved.
Proteolysis in the Escherichia coli heat shock response: a player at many levels.

Proteolysis is a fundamental process used by all forms of life to maintain homeostasis, as well as to remodel the proteome following environmental changes. Here, we explore recent advances in understanding the role of proteolysis during the heat shock response of Escherichia coli. Proteolysis both regulates and contributes directly to and the heat shock response at multiple different levels, from adjusting the levels of the master heat shock response regulator (σ32), to eliminating damaged cellular proteins, to altering the activity of chaperones that refold heat-denatured proteins. Recent results illustrate the complexity of the heat shock response and the pervasive role that proteolysis plays in both the cellular response to heat shock and the subsequent limiting of the response, as cells return to a more ‘normal’ physiological state.
A fluid dynamic formulation of the isometric embedding problem in differential geometry

The isometric embedding problem is a fundamental problem in differential geometry. A longstanding problem is con- sidered in this paper to characterize intrinsic metrics on a two- dimensional Riemannian manifold which can be realized as iso- metric immersions into the three-dimensional Euclidean space. A remarkable connection between gas dynamics and differential ge- ometry is discussed. It is shown how the fluid dynamics can be used to formulate a geometry problem. The equations of gas dynamics are first reviewed. Then the formulation using the fluid dynamic variables in conservation laws of gas dynamics is presented for the isometric embedding problem in differential geometry.
Absence of certain exchange driven instabilities of an electron gas at high densities

In the high-density limit the exchange energy easily overcomes the correlation energy in both two- and three-dimensional electron liquids. It is therefore reasonable to inquire if the class of exchange driven instabilities first discussed by Overhauser within the Hartree-Fock theory could be of relevance in this limit. Our analysis shows that this is not the case at least for distorted states represented by a single Slater determinant.
To formalize or not to formalize: Entrepreneurship and pro-market institutions

Abstract In this paper, we examine the effects of pro-market institutions on both formal and informal entrepreneurship. While formal entrepreneurship has long been studied in economic literature, informal entrepreneurship has been less frequently discussed. The purpose of this paper, therefore, is not only to examine the impact of pro-market institutions, but also to foster a better understanding of, and introduce a method to measure, informal entrepreneurship. For the purpose of this paper, pro-market institutions are broken into their two main components: economic liberalization and governance levels. The arguments posit that economic liberalization positively impacts both formal and informal entrepreneurship while governance levels have a positive impact on formal entrepreneurship but a negative effect on informal entrepreneurship. Furthermore, governance levels reduce informal entrepreneurship to a greater extent than they increase formal entrepreneurship, resulting in a net reduction in entrepreneurial activity. The analyses of a panel covering 51 countries from 2002–2009 provide robust support for these arguments.
Multiscale Modeling of Biological Functions: From Enzymes to Molecular Machines (Nobel Lecture)

Adetailed understanding of the action of biological molecules is a pre-requisite for rational advances in health sciences and related fields. Here, the challenge is to move from available structural information to a clear understanding of the underlying function of the system. In light of the complexity of macromolecular complexes, it is essential to use computer simulations to describe how the molecular forces are related to a given function. However, using a full and reliable quantum mechanical representation of large molecular systems has been practically impossible. The solution to this (and related) problems has emerged from the realization that large systems can be spatially divided into a region where the quantum mechanical description is essential (e.g. a region where bonds are being broken), with the remainder of the system being represented on a simpler level by empirical force fields. This idea has been particularly effective in the development of the combined quantum mechanics/molecular mechanics (QM/MM) models. Here, the coupling between the electrostatic effects of the quantum and classical subsystems has been a key to the advances in describing the functions of enzymes and other biological molecules. The same idea of representing complex systems in different resolutions in both time and length scales has been found to be very useful in modeling the action of complex systems. In such cases, starting with coarse grained (CG) representations that were originally found to be very useful in simulating protein folding, and augmenting them with a focus on electrostatic energies, has led to models that are particularly effective in probing the action of molecular machines. The same multiscale idea is likely to play a major role in modeling of even more complex systems, including cells and collections of cells.
Differential equations and duality in massless integrable field theories at zero temperature

Abstract Functional relations play a key role in the study of integrable models. We argue in this paper that for massless field theories at zero temperature, these relations can in fact be interpreted as monodromy relations. Combined with a recently discovered duality, this gives a way to bypass the Bethe ansatz, and compute directly physical quantities as solutions of a linear differential equation, or as integrals over a hyperelliptic curve. We illustrate these ideas in details in the case of the c=1 theory, and the associated boundary sine-Gordon model.
Oxygen isotope zoning in garnets from Franciscan eclogite blocks: evidence for rock–buffered fluid interaction in the mantle wedge

The oxygen isotope compositions of eclogite and amphibolite garnets from Franciscan Complex high-grade blocks and actinolite rinds encasing the blocks were determined to place constraints on their fluid histories. SIMS oxygen isotope analysis of single garnets from five eclogite blocks from three localities (Ring Mountain, Mount Hamilton, and Jenner Beach) shows an abrupt decrease in the δ18O value by ~1–3 ‰ from core to rim at a distance of ~120 ± 50 μm from the rim in nine out of the 12 garnets analyzed. In contrast, amphibolite garnets from one block (Ring Mountain) analyzed show a gradual increase in δ18O value from core to rim, implying a different history from that of the eclogite blocks. Values of δ18O in eclogite garnet cores range from 5.7 to 11.6 ‰, preserving the composition of the eclogite protolith. The abrupt decrease in the δ18O values of the garnet rims to values ranging from 3.2 to 11.2 ‰ suggests interaction with a lower δ18O fluid during the final stages of growth during eclogite facies metamorphism (450–600 °C). We hypothesize that this fluid is sourced from the serpentinized mantle wedge. High Mg, Ni, and Cr contents of actinolite rinds encasing the blocks also support interaction with ultramafic rock. Oxygen isotope thermometry using chlorite and phengite versus actinolite of rinds suggests temperatures of 185–240 °C at Ring Mountain and Mount Hamilton. Rind formation temperatures together with the lower δ18O garnet rims suggest that the blocks were in contact with ultramafic rock from the end of garnet growth through low-temperature retrogression. We suggest a tectonic model in which oceanic crust is subducted at the initiation of subduction and becomes embedded in the overlying mantle wedge. As subduction continues, metasomatic exchange between high-grade blocks and surrounding ultramafic rock is recorded in low δ18O garnet rims, and later as temperatures decrease, with rind formation.
Lattice congruences, fans and Hopf algebras

We give a unified explanation of the geometric and algebraic properties of two well-known maps, one from permutations to triangulations, and another from permutations to subsets. Furthermore we give a broad generalization of the maps. Specifically for any lattice congruence of the weak order on a Coxeter group we construct a complete fan of convex cones with strong properties relative to the corresponding lattice quotient of the weak order. We show that if a family of lattice congruences On the symmetric groups satisfies certain compatibility conditions then the family defines a sub Hopf algebra of the Malvenuto-Reutenauer Hopf algebra of permutations. Such a sub Hopf algebra has a basis which is described by a type of pattern avoidance. Applying these results. we build the Malvenuto Reutenauer algebra as the limit of an infinite sequence of smaller algebras.Where the second algebra in the sequence is the Hopf algebra of non-commutative symmetric functions. We also associate both a fan and a Hopf algebra to a set of permutations which appears to be equinumerous with the Baxter permutations.
Quasi-iso-focal hole pattern formation by Checker-Board PSM (CB-PSM)

A novel RET, which enables on-grid sub-50 nm hole pattern formation with ArF immersion lithography, has been developed. One of the authors has found quasi-iso-focal point image generation at the center of square area of high transmission embedded attenuating phase shift mask (EA-PSM), where four small openings are laid out at the corners of the area, utilizing an optimized quadrupole illumination. As an extension of continuous configuration, checker-board like mask pattern arrangement is created. In the mask, small openings and opaque pads are arranged like as checkerboard, whose base pitch is around resolution limit of targeted optical system. The mask pattern arrangement is named as "Checker-Board PSM (CB-PSM)". By eliminating any one opening from "checker-board", very fine point image is generated at the place. Because four openings around the eliminated one are necessary for the fine imaging characteristic, minimum distance between the point images is about the double of that for resolution limit. After simulation study of imaging, experiments are carried out to prove the fine imaging performance utilizing ArF immersion optics with NA=1.07 and a tri-level resist system. As a result, sub-50nm isolated hole is successfully formed with DOF larger than 200 nm. Simultaneously, ~ 60 nm semi-dense hole with pitch of 240 nm is printed with over 200 nm DOF. Moreover, application of conventional mask pattern arrangement, ultimately dense hole of 140nm pitch is well formed. As a conclusion, we believe that CB-PSM is a promising candidate for hole pattern formation at 32 nm node and beyond.
Efficiently Learning Ising Models on Arbitrary Graphs

graph underlying an Ising model from i.i.d. samples. Over the last fifteen years this problem has been of significant interest in the statistics, machine learning, and statistical physics communities, and much of the effort has been directed towards finding algorithms with low computational cost for various restricted classes of models. Nevertheless, for learning Ising models on general graphs with p nodes of degree at most d, it is not known whether or not it is possible to improve upon the pd computation needed to exhaustively search over all possible neighborhoods for each node.In this paper we show that a simple greedy procedure allows to learn the structure of an Ising model on an arbitrary bounded-degree graph in time on the order of p2. We make no assumptions on the parameters except what is necessary for identifiability of the model, and in particular the results hold at low-temperatures as well as for highly non-uniform models. The proof rests on a new structural property of Ising models: we show that for any node there exists at least one neighbor with which it has a high mutual information.
Organometallic Route to the Chemical Vapor Deposition of Titanium Carbide Films at Exceptionally Low Temperatures

Titanium carbide, TiC, is one of the hardest materials known (9-10 Mohs), possesses remarkable thermal stability (mp 3067/sup 0/C), and is essentially unaffected by acids and aqueous alkali. These properties make TiC a very useful material for such applications as first-wall coatings for fusion reactors. Unfortunately, crystalline TiC is also brittle, and this limits its structural applications at low temperatures. With present industrial technology, only crystalline TiC coatings can be deposited on complex shapes; the commercial process involves chemical vapor deposition from hydrogen, methane, and titanium tetrachloride at 1000/sup 0/C. More recently, plasma-assisted chemical vapor deposition techniques have been applied to the synthesis of TiC coatings, but these methods also require high temperatures, in excess of 1200/sup 0/C. They now report a simple and powerful chemical vapor deposition (CVD) method for preparing thin films of TiC using an organometallic precursor at exceptionally low temperatures (approx. 150/sup 0/C). Tetraneopentyltitanium, Ti(CH/sub 2/C(CH/sub 3/)/sub 3/)/sub 4/ was chosen for metal-organic chemical vapor deposition (MOCVD) studies since it volatilizes easily and has been reported to thermolyze at low temperature. They have devised an improved synthesis of Ti(CH/sub 2/C(CH/sub 3/)/sub 3/)/sub 4/: interaction of Ti(OCH/sub 2/CH/sub 3/)/sub 4/ with 4 equi of LiCH/sub 2/C(CH/sub 3/)/submore » 3/ in pentane followed by sublimation at 50/sup 0/C (10/sup -3/ torr) gives yellow crystals of the titanium alkyl.« less
On measuring the frequency-difference limen for short tones

The standard deviation of the distribution of matching frequencies in a two-interval pitch-matching experiment and the width of the psychometric function in a two-interval frequency-discrimination experiment both provide measures of the frequency-difference limen (DL). We compared DLs as measured by these two methods for tones of short duration, using all nine pairings of durations 12, 25, and 50 msec, at nominal frequencies of 200, 342,584, and 1000 Hz. We found that the two experiments gave qualitatively different results. In frequency discrimination, the DL decreased as the duration of either the standard or the comparison tone increased, as expected from statistical decision theory in one dimension. In pitch matching, the DL was smallest whenever the standard and comparison tones had equal durations. To explain this dichotomy, we suggest that, for tones of short duration, a pitch-matching experiment permits a multidimensional comparison of two tones, but that a frequency-discrimination experiment forces a comparison along a single perceptual dimension.
Laws of inertia in higher degree binary forms

We consider representations of real forms of even degree as a linear combination of powers of real linear forms, counting the number of positive and negative coefficients. We show that the natural generalization of Sylvester's Law of Inertia holds for binary quartics, but fails for binary sextics.
Synthesis and characterization of triaminecobalt(III) complexes and acid hydrolysis kinetics of fac-[Codpt(H2O)nX3−n]n+ (X = Cl, Br; n = 0,1,2)

Abstract The complexes CodptX 3 and [Codpt(H 2 O)X 2 ]ClO 4 (X = Cl, Br; dpt = dipropylenetriamine = NH(CH 2 CH 2 CH 2 NH 2 ) 2 ) have been prepared and characterized. Rate constants (s −1 ) for aqueous solution at 25 °C and μ = 0.5 M (NaClO 4 ), for the acid-independent sequential ractions. have been measured spectrophotometrically. For X = Cl: k 1 ⋍ 2 × 10 −2 , k 2 = 1.7 × 10 −4 and k 3 = 4.8 × 10 −6 , and for X = Br: k 1 ⋍ 2 × 10 −2 , k 2 = 5.25 × 10 −4 and k 3 = 2.5 × 10 −5 The primary equation was found to be acid independent, while the secondary and tertiary aquations were acid-inhibited reactions. For the second step, the rate of the reaction was given by the rate equation where C t is the complex concentration in the aqua-and hydroxodihalo species, k ′ 2 is the rate constant for the acid-dependent pathway and K a is the equilibrium constant between the hydroxo and aqua complex ions. The activation parameters were evaluated, for X = Cl: Δ H ≠ 2 = 106.3 ± 0.4 kJ mol −1 and Δ S ≠ 2 = 40.2 ± 1.7 J K −1 mol − , and for X = Br: Δ H ≠ 2 = 91.6 ± 0.4 kJ mol −1 and Δ S ≠ 2 = 0.4 ± 1.7 J K −1 mol −1 . The results are discussed and detailed comparisons of the reactivities of these complexes with other haloaminecobalt(III) species are presented.
Design Method for Turbomachine Blades With Finite Thickness by the Circulation Method

This paper presents a procedure to extend a recently developed three-dimensional inverse method for infinitely thin blades to handle blades with finite thickness. In this inverse method, the prescribed quantities are the blade pressure loading and the blade thickness distributions, and the calculated quantity is the blade mean camber line. The method is formulated in the fully inverse mode whereby the blade shape is determined iteratively using the flow-tangency condition along the blade surfaces. Design calculations are presented for an inlet guide vane, an impulse turbine blade, and a compressor blade in the two-dimensional inviscid- and incompressible-flow limit. Consistency checks are carried out for these design calculations using a panel analysis method and the analytical solution for the Gostelow profile.
Amphetamine psychosis: Behavioral and biochemical aspects

Publisher Summary This chapter discusses the behavioral and biochemical aspects of amphetamine psychosis. Amphetamine psychosis was characterized by a brisk emotional reaction, usually in the direction of anxiety amphetamine psychosis was rather strikingly similar to schizophrenia in its presentation; however, these two conditions could be differentiated by the presence of thought disorder that is prominent in schizophrenia and lacking in amphetamine psychosis The pharmacologic manipulation of dopaminergic mechanisms is almost certainly not without effect on other central nervous system systems and certain effects considered dopaminergic may indirectly be mediated by these other systems. Physostigmine can both block and abolish the stereotypy in rats induced by the administration of methylphenidate.
Electrical stimulation of rewarding hypothalamic sites in the 13-lined ground squirrel, Citellus tridecemlineatus, during hibernation: Sensitivity and thermogenic effects

Abstract 1. 1. Ground squirrels were chronically prepared for the determination of hypothalamic stimulus thresholds during hibernation at brain temperatures ( T br ) of 9–15°C by observations of heart rate (HR), neck muscle activity (EMG) and T br changes. 2. 2. Preliminary tests on euthermic squirrels showed that the hypothalamic sites were rewarding since animals self-stimulated the sites at a rate proportional to the stimulus intensity. 3. 3. During bouts of hibernation, the threshold for increased HR varied from 2- to 5-fold but did not vary significantly with T br or the percentage of the hibernation bout elapsed. 4. 4. Stimulation of the hypothalamus resulted in rises of T br during hibernation only if the stimulus produced cardioacceleration.
Kinetochore assembly: if you build it, they will come

Accurate chromosome segregation requires the interaction of chromosomes with the microtubules from the mitotic spindle. This interaction is mediated by the macro-molecular kinetochore complex, which assembles only at the centromeric region of each chromosome. However, how this site is specified and how assembly of the kinetochore structure is regulated in coordination with cell cycle progression remains unclear. Recent studies have begun to shed light on the mechanisms underlying assembly of this complex structure.
Moment induced by liquid payload during spin-up without a critical layer

Abstract : For a fully spun-up liquid payload, eigenfrequencies and liquid side moments induced by projectile coning motion have been computed by a linear boundary layer theory. For partially spun-up liquids, this theory can fail due to the presence of a critical layer in which the local angular velocity of the spinning motion is near the angular velocity of the projectile's coning motion. Late in the spin-up process, when more than 90% of the spin angular momentum has been acquired by the liquid, a critical layer usually does not exist. In this report, a linear-boundary-layer theory is developed to predict eigenfrequencies and the liquid moment during late spin-up times. The predicted eigenfrequencies agree well with those computed by the linearized Navier-Stokes technique of Gerber and Sedney. The side moments predicted by the linear-boundary-layer theory are available to projectile designers for flight stability analysis.
Optimal Design of a Helmholtz Resonator With a Flexible End Plate

A multi-objective optimization formulation to design a Helmholtz resonator with a flexible end plate is studied. The optimization formulation generates a Pareto curve of design solutions that quantify the trade-off between the optimization goals: minimum resonator volume and maximum transmission loss across a specified frequency range. The optimization problem is formulated and solved in the following manner. First, a mathematical formulation for the transmission loss of the Helmholtz resonator with a flexible plate is completed based on the design parameters. Then, the weighted transmission loss across a specified frequency range and a minimum resonator volume are defined as optimization objectives. Finally, the Pareto curve of optimum design solutions is calculated using a gradient-based approach via the e-constraint method. The optimization results allow the designer to select resonator design parameters that meet the requirements for both transmission loss and resonator volume. To validate the optimization results, one optimal Helmholtz resonator is manufactured and experimentally confirmed.Copyright © 2012 by ASME
Total Parenteral Nutrition in the Cancer Patient

TOTAL parenteral nutrition (TPN) is a life-saving method of nutritional support for patients who are unable to ingest, digest, or absorb sufficient nutrients to prevent death from starvation. The d...
Rapid synthesis of the N-methylwelwitindolinone skeleton.

An efficient, convergent synthesis of the core bicyclo[4.3.1]decane ring system of welwitindolinones is described. Key steps in the synthesis include an intramolecular palladium-catalyzed enolate arylation reaction to create the desired bicyclic skeleton and a Curtius rearrangement to install the bridgehead isocyanate unit.
Femtosecond Fourier-transform spectroscopy of low-frequency intermolecular motions in weakly interacting liquids

Abstract We present new results on the temperature-dependent collision-induced low-frequency Raman spectrum of the spherical top molecule CCl4, obtained using optical-heterodyne-detected, femtosecond Fourier-transform Raman-induced Kerr-effect spectroscopy. A spectral shift to lower frequencies with increasing temperatures has been observed.
Multi-dimensional cosmological radiative transfer with a Variable Eddington Tensor formalism

Abstract We present a new approach to numerically model continuum radiative transfer based on the Optically Thin Variable Eddington Tensor (OTVET) approximation. Our method insures the exact conservation of the photon number and flux (in the explicit formulation) and automatically switches from the optically thick to the optically thin regime. It scales as N log N with the number of hydrodynamic resolution elements and is independent of the number of sources of ionizing radiation (i.e. works equally fast for an arbitrary source function). We also describe an implementation of the algorithm in a Soften Lagrangian Hydrodynamic code (SLH) and a multi-frequency approach appropriate for hydrogen and helium continuum opacities. We present extensive tests of our method for single and multiple sources in homogeneous and inhomogeneous density distributions, as well as a realistic simulation of cosmological reionization.
Efficient geometric algorithms for workpiece orientation in 4- and 5-axis NC machining

Abstract In 4- and 5-axis NC machines, the time to dismount, recalibrate, and remount the workpiece after each set of accessible faces of the workpiece has been machined can be considerable in comparison to the actual machining time. Unfortunately, the problem of minimizing the number of setups is NP-hard. In this paper, efficient algorithms are given for a greedy heuristic, where the goal is to find an orientation for the workpiece which maximizes the number of faces that can be machined in a single setup—using either a ball-end or a filletend cutter. The algorithms are based on geometric duality, topological sweep, interesting new properties concerning intersection and covering on the unit-sphere, and on techniques for efficiently constructing and searching an arrangement of polygons on the unit-sphere. The results imply that the optimal number of set-ups can be approximated to within a logarithmic factor. Evidence is also provided that it may not be possible to improve substantially on the proposed algorithms.
Asset liquidity, debt covenants, and managerial discretion in financial distress:: the collapse of L.A. Gear

Abstract A hot growth stock in the 1980s, L.A. Gear's equity fell from $1 billion in market value in 1989 to zero in 1998. For over six years as revenues declined precipitously, management tried a series of radical strategy shifts while subsidizing the firm's large losses through working-capital liquidations. The L.A. Gear case illustrates that asset liquidity (broadly construed, not limited to excess cash) can give managers substantial operating discretion during financial distress. It also shows (1) that debt covenants can be stronger disciplinary mechanisms than requirements to meet cash interest payments, (2) why debt contracts typically constrain earnings instead of cash flow, (3) why cash balances are not equivalent to negative debt, and (4) why debt maturity matters. We find that many firms have highly liquid asset structures, thus their managers have the potential to subsidize losing operations should the need arise.
On the t-term rank of a matrix

Abstract For t a positive integer, the t -term rank of a ( 0 , 1 ) -matrix A is defined to be the largest number of 1 s in A with at most one 1 in each column and at most t 1 s in each row. Thus the 1 -term rank is the ordinary term rank. We generalize some basic results for the term rank to the t -term rank, including a formula for the maximum term rank over a nonempty class of ( 0 , 1 ) -matrices with the same row sum and column sum vectors. We also show the surprising result that in such a class there exists a matrix which realizes all of the maximum terms ranks between 1 and t .
Adaptive control of grid quality for computational fluid dynamics

A grid adaptation technique is presented that improves the quality of computational grids for fluid flow calculations. The method adapts a grid directly to certain grid properties, such as grid skewness, grid stretching, or gridline kinking. A numerical mapping is employed that transforms the grid into a parametric space. Adaptive grid control is achieved by modifying the mapping functions through he effects of grid control sources extracted from the distribution of specific grid properties. A rediscretization of the modified parametric domain results in a grid-quality-adapted grid when mapped back to the physical space. The procedure retains the basic properties of the initial grid while reducing undesirable grid characteristics. The method is demonstrated with several examples.
Statistical mechanics and black hole thermodynamics

Abstract Black holes are thermodynamic objects, but despite recent progress, the ultimate statistical mechanical origin of black hole temperature and entropy remains mysterious. Here I summarize an approach in which the entropy is viewed as arising from “would-be pure gauge” degrees of freedom that become dynamical at the horizon. For the (2+1)-dimensional black hole, these degrees of freedom can be counted, and yield the correct Bekenstein-Hawking entropy; the corresponding problem in 3+1 dimensions remains open.
Raman Spectrum of Heavy Water

THE Raman spectrum of 80 per cent heavy water obtained with a sample supplied by Prof. H. S. Taylor of Princeton, when compared with the spectrum of the 18 per cent material previously reported1, shows that the water molecule with two atoms of heavy hydrogen gives a Raman band with a frequency difference of 2517, while the molecule with one atom of heavy and one of light hydrogen gives two bands, one of frequency difference of 2623, the other of 3500. Ordinary water gives a band with frequency difference 3445. A single photograph of a sample of given concentration does not bring out this shift as the bands overlap ; but by superposing the two photographs taken with different concentrations, the shift in the centre of gravity of the bands comes out in a very striking manner.
Stationary nonequilibrium states in boundary-driven Hamiltonian systems: Shear flow

We investigate stationary nonequilibrium states of systems of particles moving according to Hamiltonian dynamics with specified potentials. The systems are driven away from equilibrium by Maxwell-demon “reflection rules” at the walls. These deterministic rules conserve energy but not phase space volume, and the resulting global dynamics may or may not be time reversible (or even invertible). Using rules designed to simulate moving walls, we can obtain a stationary shear flow. Assuming that for macroscopic systems this flow satisfies the Navier-Stokes equations, we compare the hydrodynamic entropy production with the average rate of phase-space volume compression. We find that they are equalwhen the velocity distribution of particles incident on the walls is a local Maxwellian. An argument for a general equality of this kind, based on the assumption of local thermodynamic equilibrium, is given. Molecular dynamic simulations of hard disks in a channel produce a steady shear flow with the predicted behavior.
BiMOS transistors: merged bipolar/sidewall MOS transistors

Summary form only given. A technique to form device structures which merge MOS and bipolar transistors into bipolar/sidewall MOS transistors (BiMOS) is discussed. The concept and feasibility of this technique are demonstrated by fabricating and DC-characterizing the merged structures. The merged bipolar/sidewall MOS structures are formed by growing a gate oxide layer on the sidewalls of the mesa (exposed p-n junction) and depositing a polysilicon layer on the oxide to form semivertical MOS structures. Following this, the polysilicon layer is patterned and etched, and the samples are patterned and implanted to form n/sup +/ and p/sup +/ drains and sources of the sidewall MOS transistors. Using this technique, many of the typical BiCMOS subcircuit elements, such as MOS-bipolar Darlington structures (with a MOS input), can be formed. The advantage of these merged structures is that they occupy an area approximately the same as that of a bipolar transistor, while performing the functions of circuit elements composed of two transistors. >
Continuous mixture modeling via goodness-of-fit cores

This dissertation introduces a novel technique for consistently and accurately modeling the distributions of data. The technique is ideal for representing distributions that arise in a variety of problems including the driving problem of this dissertation, representing the distributions of intensities associated with tissues in medical images containing intensity inhomogeneities. Intensity inhomogeneities arise in MRimages due to inhomogeneous fields, in x-rayCTimages due to beam hardening, and in SPECTimages due to deficiencies in attenuation compensation. Within regions of such images, a tissue’s intensity distribution is Gaussian. Between regions, however, the mean and variance of a tissue’s Gaussian may vary as a result of inhomogeneities. That is, a tissue’s intensities throughout an inhomogeneous image have a generalized projective Gaussian distribution (GPGD). Traditionally, GPGDs have been modeled using finite Gaussian mixture models (FGMMs). The dissertation demonstrates that GPGDs are better represented by continuous Gaussian mixture models (CGMMs). Gaussian goodness-of-fit cores define CGMMs. For GPGDs, Monte Carlo and ROC analysis demonstrate that classifiers utilizing CGMMs provide as consistent labelings as and better true-positive rates than FGMMs. The CGMM-based classification of gray and white matter in an inhomogeneous magnetic resonanceimage is demonstrated.
Excluding electroweak baryogenesis in the MSSM

In the context of the MSSM the Light Stop Scenario (LSS) is the only region of parameter space that allows for successful Electroweak Baryogenesis (EWBG). This possibility is very phenomenologically attractive, since it allows for the direct production of light stops and could be tested at the LHC. The ATLAS and CMS experiments have recently supplied tantalizing hints for a Higgs boson with a mass of ≈ 125 GeV. This Higgs mass severely restricts the parameter space of the LSS, and we discuss the specific predictions made for EWBG in the MSSM. Combining data from all the available ATLAS and CMS Higgs searches reveals a tension with the predictions of EWBG even at this early stage. This allows us to exclude EWBG in the MSSM at greater than (90) 98% confidence level in the (non-)decoupling limit, by examining correlations between different Higgs decay channels. We also examine the exclusion without the assumption of a ≈ 125 GeV Higgs. The Higgs searches are still highly constraining, excluding the entire EWBG parameter space at greater than 90% CL except for a small window of m h ≈ 117-119 GeV.
Multi-View Stereo Reconstruction of Dense Shape and Complex Appearance

We address the problem of estimating the three-dimensional shape and complex appearance of a scene from a calibrated set of views under fixed illumination. Our approach relies on a rank condition that must be satisfied when the scene exhibits "specular + diffuse" reflectance characteristics. This constraint is used to define a cost functional for the discrepancy between the measured images and those generated by the estimate of the scene, rather than attempting to match image-to-image directly. Minimizing such a functional yields the optimal estimate of the shape of the scene, represented by a dense surface, as well as its radiance, represented by four functions defined on such a surface. These can be used to generate novel views that capture the non-Lambertian appearance of the scene.
Relating branes and matrices

We construct a general map between a Dp-brane with magnetic flux and a matrix configuration of D0-branes, by showing how one can rewrite the boundary state of the Dp-brane in terms of its D0-brane constituents. This map gives a simple prescription for constructing the matrices of fuzzy spaces corresponding to branes of arbitrary shape and topology. Since we explicitly identify the D0-brane degrees of freedom on the brane, we also derive the D0-brane charge of the brane in a very direct way including the ?-genus term. As a check on our formalism, we use our map to derive the abelian-Born-Infeld equations of motion from the action of the D0-brane matrices.
Doubly-charged gas phase cations

Unique features of doubly-charged stable organic ions are examined and the results correlated with experimental observations. Self-consistent field molecular orbital methods are used to compute structures and stabilities of CnH 2 2+ (n=2–9) ions which are prominent in electron impact ionization of hydrocarbon molecules. A simple curve crossing model is employed to rationalize charge transfer reactions of these ions.
Non-existence of certain semistable abelian varieties

We show that there is no semistable abelian variety defined over ℚ with bad reduction at exactly one prime p≤ 7.
Object localization using color, texture and shape

Abstract We address the problem of localizing objects using color, texture and shape. Given a handrawn sketch for querying an object shape, and its color and texture, the proposed algorithm automatically searches the image database for objects which meet the query attributes. The database images do not need to be presegmented or annotated. The proposed algorithm operates in two stages. In the first stage, we use local texture and color features to find a small number of candidate images in the database, and identify regions in the candidate images which share similar texture and color as the query. To speed up the processing, the texture and color features are directly extracted from the Discrete Cosine Transform (DCT) compressed domain. In the second stage, we use a deformable template matching method to match the query shape to the image edges at the locations which possess the desired texture and color attributes. This algorithm is different from other content-based image retrieval algorithms in that: (i) no presegmentation of the database images is needed, and (ii) the color and texture features are directly extracted from the compressed images. Experimental results demonstrate performance of the algorithm and show that substantial computational savings can be achieved by utilizing multiple image cues.
The Equivalence of Sampling and Searching

In a sampling problem, we are given an input x?{0,1} n , and asked to sample approximately from a probability distribution $\mathcal{D}_{x}$ over $\operatorname{poly} ( n ) $ -bit strings. In a search problem, we are given an input x?{0,1} n , and asked to find a member of a nonempty set A x with high probability. (An example is finding a Nash equilibrium.) In this paper, we use tools from Kolmogorov complexity to show that sampling and search problems are "essentially equivalent." More precisely, for any sampling problem S, there exists a search problem R S such that, if $\mathcal{C}$ is any "reasonable" complexity class, then R S is in the search version of $\mathcal{C}$ if and only if S is in the sampling version. What makes this nontrivial is that the same R S works for every $\mathcal{C}$ . As an application, we prove the surprising result that SampP=SampBQP if and only if FBPP=FBQP. In other words, classical computers can efficiently sample the output distribution of every quantum circuit, if and only if they can efficiently solve every search problem that quantum computers can solve.
Expression of an extracellular matrix metalloproteinase inducer (basigin) in the human ovary and ovarian endometriosis

Objective To characterize the expression of basigin in ovarian endometriotic tissue, normal ovary, and endometrium during the menstrual cycle. Design Controlled, retrospective study for evaluation of basigin expression in archived specimens. Setting Academic research environment: University of Kentucky College of Medicine. Patient(s) Archived surgical specimens selected by retrospective chart review of age-matched (39 ± 2.5 years) patients with and without ovarian endometriosis. Intervention(s) None. Main Outcome Measure(s) Expression localization of basigin mRNA and protein. Result(s) Basigin (mRNA and protein) was localized to granulosa cells (follicles of all stages), the ovarian surface epithelium, and granulosa and theca lutein of corpora lutea. Differential patterns of expression were apparent among samples of eutopic endometrium collected during the proliferative and secretory stages. In endometriotic lesions on the ovary, basigin was detected in the glandular epithelia and stroma of proliferative and secretory phase samples, but patterns of expression were unsynchronized with those of the eutopic endometrium from the same patient. Conclusion(s) The current data demonstrate unique expression patterns of basigin in the human ovary and endometriotic tissue, thereby supporting a possible role in normal ovarian function and in the dysregulation of proteolytic matrix metalloproteinases in endometriosis.
Using Web Tools, Collaborating, and Learning Online

This case study reports how graduate students learned in a constructivist online course in educational telecommunications. The study investigated the ways students learned to use technology and lea...
Adaptive Multicast Wormhole Routing in 2D Mesh Multicomputers

The issues of adaptive multicast wormhole routing in 2D mesh multicomputers are studied. Three adaptive multicast wormhole routing strategies are proposed and evaluated. The methods include minimal partially adaptive, minimal fully adaptive, and nonminimal adaptive routing. All the algorithms are shown to be deadlock-free. A study has been conducted that compares the performance of these multicast algorithms. The results show that the minimal fully adaptive routing method creates the least traffic; however, double vertical channels are required in order to avoid deadlock. The nonminimal routing algorithm exhibits the best adaptivity, although it creates more network traffic than the other methods.
Markov perfect equilibria in industries with complementarities

This paper considers the existence and computation of Markov perfect equilibria in games with a “monotone” structure. Specifically, it provides a constructive proof of the existence of Markov perfect equilibria for a class of games in which a) there is a continuum of players, b) each player has the same per period payoff function and c) these per period payoff functions are supermodular in the player's current and past action and have increasing differences in the player's current action and the entire distribution of actions chosen by other players. The Markov perfect equilibria that are analyzed are symmetric, not in the sense that each player adopts the same action in any period, but rather in the sense that each player uses the same policy function. Since agents are typically distributed across many states they will typically take different actions. The formal environment considered has particular application to models of industries (or economies) in which firms face costs of price adjustment. It is in this context that the results are developed.