cssi/SciSciGPT-SciSciNet huggingface dataset:
Thermal Nanofluid Property Model With Application to Nanofluid Flow in a Parallel Disk System—Part II: Nanofluid Flow Between Parallel Disks

This is the second part of a two-part paper which proposes a new theory explaining the experimentally observed enhancement of the thermal conductivity, k nf , of nanofluids (Part I) and discusses simulation results of nanofluid flow in an axisymmetric jet-impingement cooling system using different k nf -models (Part II). Specifically, Part II provides numerical simulations of convective nanofluid heat transfer in terms of velocity profiles, friction factor, temperature distributions, and Nusselt numbers, employing the new k nf -model. Flow structures and the effects of nanoparticle addition on heat transfer and entropy generation are discussed as well. Analytical expressions for velocity profiles and friction factors, assuming quasi-fully-developed flow between parallel disks, have been derived and validated for nanofluids as well. Based on the numerical simulation results for both alumina-water nanofluids and pure water, it can be concluded that nanofluids show better heat transfer performance than convectional coolants with no great penalty in pumping power. Furthermore, the system's entropy generation rate is lower for nanofluids than for pure water.
Device performance of AlGaN-based 240-300-nm deep UV LEDs

Deep ultraviolet light emitting diodes (LEDs) with emission wavelengths shorter than 300 nm have been grown by metalorganic vapor phase epitaxy. A bottom emitting LED design is used which requires a high-Al content Al x Ga 1-x N (x = 0.5 - 0.8 ) buffer layer which has sufficient conductivity and is transparent to the quantum well emission wavelength. LEDs were flip chip mounted to a silicon submount which provides for good thermal performance as well as improved light extraction. For large area 1 mm x 1 mm LEDs emitting at 297 nm, an output power as high as 2.25 mW under direct current operation has been demonstrated at 500 mA with a forward voltage of 12.5 volts. For shorter wavelength LEDs emitting at 276 nm, an output power as high as 1.3 mW has been demonstrated under direct current operation at 300 mA with a forward voltage of 9.2 volts. Recent improvements in heterostructure design have resulted in quantum well emission at 276 nm with a peak intensity that is 330 times stronger than the largest sub-bandgap peak. LEDs with emission wavelengths as short as 237 nm have also been demonstrated.
Quasi-2D dynamic jamming in cornstarch suspensions: visualization and force measurements

We report experiments investigating jamming fronts in a floating layer of cornstarch suspension. The suspension has a packing fraction close to jamming, which dynamically turns into a solid when impacted at a high speed. We show that the front propagates in both axial and transverse direction from the point of impact, with a constant ratio between the two directions of propagation of approximately 2. Inside the jammed solid, we observe an additional compression, which results from the increasing stress as the solid grows. During the initial growth of the jammed solid, we measure a force response that can be completely accounted for by added mass. Only once the jamming front reaches a boundary, the added mass cannot account for the measured force anymore. We do not, however, immediately see a strong force response as we would expect when compressing a jammed packing. Instead, we observe a delay in the force response on the pusher, which corresponds to the time it takes for the system to develop a close to uniform velocity gradient that spans the complete system.
Conflict among testing procedures

Abstract This paper demonstrates that under certain conditions the Lagrange Multiplier test provides a better approximation to the asymptotic X 2 distribution than the more familiar Wald and Likelihood Ratio tests.
Electroweak symmetry breaking from dimensional deconstruction

We propose a new class of four-dimensional theories for natural electroweak symmetry breaking, relying neither on supersymmetry nor on strong dynamics at the TeV scale. The new TeV physics is perturbative, and radiative corrections to the Higgs mass are finite. The softening of this mass occurs because the Higgs is an extended object in theory space, resulting in an accidental symmetry. A novel Higgs potential emerges naturally, requiring a second lightSU(2)doublet scalar. 2001 Published by Elsevier Science B.V.
I/O-efficient point location using persistent B-trees

We present an external planar point location data structure that is I/O-efficient both in theory and practice.The developed structure uses linear space and answers a query in optimal O(log BN) I/Os, where B is the disk block size. It is based on a persistent B-tree, and all previously developed such structures assume a total order on the elements in the structure. As a theoretical result of independent interest, we show how to remove this assumption.Most previous theoretical I/O-efficient planar point location structures are relatively complicated and have not been implemented. Based on a bucket approach, Vahrenhold and Hinrichs therefore developed a simple and practical, but theoretically non-optimal, heuristic structure. We present an extensive experimental evaluation that shows that, on a range of real-world Geographic Information Systems (GIS) data, our structure uses a similar number of I/Os as the structure of Vahrenhold and Hinrichs to answer a query. On a synthetically generated worst-case dataset our structure uses significantly fewer I/Os.
Precision of spiral-bevel gears

The kinematic errors in spiral bevel gear trains caused by the generation of nonconjugate surfaces, by axial displacements of the gears during assembly, and by eccentricity of the assembled gears were determined. One mathematical model corresponds to the motion of the contact ellipse across the tooth surface, (geometry I) and the other along the tooth surface (geometry II). The following results were obtained: (1) kinematic errors induced by errors of manufacture may be minimized by applying special machine settings, the original error may be reduced by order of magnitude, the procedure is most effective for geometry 2 gears, (2) when trying to adjust the bearing contact pattern between the gear teeth for geometry 1 gears, it is more desirable to shim the gear axially; for geometry II gears, shim the pinion axially; (3) the kinematic accuracy of spiral bevel drives are most sensitive to eccentricities of the gear and less sensitive to eccentricities of the pinion. The precision of mounting accuracy and manufacture are most crucial for the gear, and less so for the pinion.
Praseodymium Trifluoromethylsulfonate as an Efficient and Recyclable Catalyst for the Synthesis of α‐Aminonitriles

Abstract Praseodymium trifluoromethylsulfonate (triflate) has been found to be an efficient and recyclable catalyst for the synthesis of α‐aminonitrile by a one‐pot, three‐component condensation of aldehydes, amines, and trimethylsilyl cyanide at room temperature.
Fundamental groups of links of isolated singularities

© 2014 American Mathematical Society. All rights reserved. We study fundamental groups of projective varieties with normal crossing singularities and of germs of complex singularities. We prove that for every finitely-presented group G there is a complex projective surface S with simple normal crossing singularities only, so that the fundamental group of S is isomorphic to G. We use this to construct 3-dimensional isolated complex singularities so that the fundamental group of the link is isomorphic to G. Lastly, we prove that a finitely- presented group G is Q-superperfect (has vanishing rational homology in dimensions 1 and 2) if and only G if is isomorphic to the fundamental group of the link of a rational 6-dimensional complex singularity.
Expected performance of cryoarray

Abstract WIMP-nucleon cross sections σ ⪅ 10−9 pb may be probed by ton-scale experiments with low thresholds and background rates ∼ 20 events per year. An array of cryogenic detectors (“CryoArray”) could perform well enough to reach this goal. Sufficient discrimination and background suppression of photons has already been demonstrated. Reduction of neutron backgrounds may be achieved by siting the experiment deep enough. Removal of the surface-electron backgrounds alone has not yet been demonstrated, but the reductions required even for this troublesome background are quite modest and appear achieveable.
Linear recurrences in the degree sequences of monomial mappings

Let A be an integer matrix, and let f A be the associated monomial map. We give a connection between the eigenvalues of A and the existence of a linear recurrence relation in the sequence of degrees.
A synthetic protective put strategy for phased investment in projects without an outright deferral

This paper proposes and computationally demonstrates a synthetic protective put strategy for real options. Specifically, it deals with the problem of deferral option when an outright deferral is not permissible owing to competitive pressures. It is demonstrated that, in such a situation, an appropriate strategy would be to invest in the new project in phases rather than doing it all at once. The replicating portfolio for a protective put on the project is obtained by setting the owner's equity in the project equal to the price of a call option on the value of the project. This is a logical extension of the financial protective put to the real options scenario and is relatively simple and practicable for businesses to adopt and apply.
Approximating Resonances with the Complex Absorbing Potential Method

ABSTRACT We study the Complex Absorbing Potential (CAP) Method in computing quantum resonances of width −Im z(h) ≤ c(h) = O(h N ), N ≫ 1. We show that up to an error, M ≫ 1, resonances are perturbed eigenvalues of the CAP Hamiltonian P(h) − i W, and vice versa, where W is the CAP with non-negative real part supported outside the trapping region. In some cases, the error terms are exponentially small.
Computational design of patterned interfaces using reduced order models

Patterning is a familiar approach for imparting novel functionalities to free surfaces. We extend the patterning paradigm to interfaces between crystalline solids. Many interfaces have non-uniform internal structures comprised of misfit dislocations, which in turn govern interface properties. We develop and validate a computational strategy for designing interfaces with controlled misfit dislocation patterns by tailoring interface crystallography and composition. Our approach relies on a novel method for predicting the internal structure of interfaces: rather than obtaining it from resource-intensive atomistic simulations, we compute it using an efficient reduced order model based on anisotropic elasticity theory. Moreover, our strategy incorporates interface synthesis as a constraint on the design process. As an illustration, we apply our approach to the design of interfaces with rapid, 1-D point defect diffusion. Patterned interfaces may be integrated into the microstructure of composite materials, markedly improving performance.
Indenylidene−Imidazolylidene Complexes of Ruthenium as Ring-Closing Metathesis Catalysts

The indenylidene−imidazolylidene complexes of ruthenium (IMes)(PR3)Cl2Ru(3-phenylindenylid-1-ene) and (IPr)(PR3)Cl2Ru(3-phenylindenylid-1-ene) (IMes = 1,3-bis(2,4,6-trimethylphenyl)imidazol-2-ylidene, IPr = 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene, and R= Ph, Cy) were prepared and found to be efficient catalyst precursors for ring-closing metathesis.
A set of genes previously implicated in the hypoxia response might be an important modulator in the rat ear tissue response to mechanical stretch

Wounds are increasingly important in our aging societies. Pathologies such as diabetes predispose patients to chronic wounds that can cause pain, infection, and amputation. The vacuum assisted closure device shows remarkable outcomes in wound healing. Its mechanism of action is unclear despite several hypotheses advanced. We previously hypothesized that micromechanical forces can heal wounds. To understand better the biological response of soft tissue to forces, rat ears in vivo were stretched and their gene expression patterns over time obtained. The absolute enrichment (AE) algorithm that obtains a combined up and down regulated picture of the expression analysis was implemented. With the use of AE, the hypoxia gene set was the most important at a highly significant level. A co-expression network analysis showed that important co-regulated members of the hypoxia pathway include a glucose transporter (slc2a8), heme oxygenase, and nitric oxide synthase2 among others. It appears that the hypoxia pathway may be an important modulator of response of soft tissue to forces. This finding gives us insights not only into the underlying biology, but also into clinical interventions that could be designed to mimic within wounded tissue the effects of forces without all the negative effects that forces themselves create.
A Preview Steering Autopilot Control Algorithm for Four-Wheel-Steering Passenger Vehicles

This paper addresses the control law design of a preview steering autopilot for a four-wheel-steering vehicle to perform automatic lane tracking. In the concept, an on-board computer vision system is used in lieu of the driver’s vision to track the roadway. The steering autopilot design is formulated as an optimal, discrete-time preview path tracking problem under the “perfect measurement” assumption. Simulation results indicate that the tracking performance of the steering autopilot was improved by preview relative to that calculated for an autopilot without preview. These results also indicate the existence of an effective preview time with which almost all the benefits of previewing future information can be obtained. This effective preview time is about three times the reciprocal of the autopilot’s bandwidth. Our study also indicates that preview steering autopilots can tolerate the use of actuators with a lower bandwidth than those designed without preview information.
Demystifying the scaling laws of dense wireless networks: No linear scaling in practice

We optimize the hierarchical cooperation protocol of Ozgur, Leveque and Tse, which is supposed to yield almost linear scaling of the capacity of a dense wireless network with the number of users n. Exploiting recent results on the optimality of “treating interference as noise” in Gaussian interference channels, we are able to optimize the achievable average perlink rate and not just its scaling law. Our optimized hierarchical cooperation protocol significantly outperforms the originally proposed scheme. On the negative side, we show that even for very large n, the rate scaling is far from linear, and the optimal number of stages t is less than 4, instead of t → ∞ as required for almost linear scaling. Combining our results and the fact that, beyond a certain user density, the network capacity is fundamentally limited by Maxwell laws, as shown by Francheschetti, Migliore and Minero, we argue that there is indeed no intermediate regime of linear scaling for dense networks in practice.
Modulation of Somatostatin Binding To Rat Pituitary Membranes by Exogenously Administered Growth Hormone

The effect of exogenously administered GH on somatostatin (SRIF) receptor regulation was studied in rat anterior pituitary membranes. A single class, high affinity specific receptor for SRIF was identified by binding studies with [125ITyrn] SRIF [binding capacity (mean ± sd), 129.4 ± 23.3 fmol/mg protein; binding affinity, 2.8 ± 0.6 × 1010 m−1]. A single injection of rat GH (150 μg) caused a significant reduction in capacity, but not in affinity, of SRIF receptors 2 and 6 h after injection (mean decrease, 23% and 24%, respectively) from that in controls. In contrast, mean SRIF binding capacity 24 h after a single injection of rat GH was increased 48% above control values, but affinity was unaffected. Measurement of membrane SRIF content indicated that these changes could not be explained by alterations in receptor occupancy. When rat GH was injected repeatedly for 3 days (150 μg/rat·day), the mean binding capacity, though not the affinity, of SRIF receptors was decreased 23% from that in controls 24 h aft...
Recoil energy distribution of hydrogen isotopes adsorbed on tungsten

Abstract The energies of adsorbed H and D recoiled from tungsten surfaces during bombardment with 3 keV Ne+ at oblique angles of incidence were measured. The energy spectra show structure that extends above the elastic recoil energy. We find that the high-energy structure results from multiple collisions, namely recoil of a H isotope followed by scattering from an adjacent W atom, and vice versa. This scattering assisted recoil process is especially prevalent for H isotopes adsorbed on W, owing to the large mass difference between the scattering partners. Such processes will tend to enhance H isotope recycling from plasma-facing W surfaces and reduce energy transfer to the W substrate.
Development of a prototype optical hydrogen gas sensor using a getter-doped polymer transducer for monitoring cumulative exposure: Preliminary results

A novel prototype optical sensor for monitoring cumulative hydrogen gas exposure was fabricated and evaluated. Chemical-to-optical transduction was accomplished by detecting the intensity of 670 nm laser light transmitted through a hydrogen getter-doped polymer film mounted at the end of an optical fiber; the transmittance of the composite film increased with uptake of hydrogen by the embedded getter. The composite film consisted of the hydrogen getter 1,4-bis(phenylethynyl)benzene, also known as DEB, with carbon-supported palladium catalyst embedded in silicone elastomer. Because the change in transmittance was irreversible and occurred continuously as the getter captured hydrogen, the sensor behaved like a dosimeter, providing a unique indication of the cumulative gas exposure.
Local approximation schemes for topology control

This paper presents a distributed algorithm for wireless ad-hoc networks that runs in polylogarithmic number of rounds in the size of the network and constructs a lightweight, linear size, (1+e)-spanner for any given e > 0. A wireless network is modeled by a d-dimensional α-quasi unit ball graph (α-UBG), which is a higher dimensional generalization of the standard unit disk graph (UDG) model. The d-dimensional α-UBG model goes beyond the unrealistic "flat world" assumption of UDGs and also takes into account transmission errors, fading signal strength, and physical obstructions. The main result in the paper is this: for any fixed e > 0, 0
Effects of single and multiple courses of antenatal glucocorticoids in preterm newborns less than 30 weeks' gestation.

Background: We compared outcomes between neonates receiving either single course, multiple courses, or no antenatal glucocorticoid exposure.Methods: We retrospectively identified neonates whose mothers received a single course (SIN) of dexamethasone, multiple (2-3) weekly courses (MULT), or no (NO) glucocorticoids. Multiple gestations and infants with chromosomal abnormalities or not receiving a full course of antenatal dexamethasone were excluded from the study. The incidences of the following outcomes were examined: respiratory distress syndrome (RDS), Grades III or IV intraventricular hemorrhage (IVH), bronchopulmonary dysplasia (BPD), necrotizing enterocolitis (NEC), retinopathy of prematurity (ROP), sepsis, and in-hospital death. Means were compared with analysis of variance and outcome variable frequencies with chi-square test.Results: A total of 147 infants were included in the analysis. There were no differences in the gestational age or growth parameters among the groups. As anticipated, infants ...
Cauchy pairs and Cauchy matrices

Abstract Let K denote a field and let X denote a finite non-empty set. Let Mat X ( K ) denote the K -algebra consisting of the matrices with entries in K and rows and columns indexed by X . A matrix C ∈ Mat X ( K ) is called Cauchy whenever there exist mutually distinct scalars { x i } i ∈ X , { x ˜ i } i ∈ X from K such that C i j = ( x i − x ˜ j ) − 1 for i , j ∈ X . In this paper, we give a linear algebraic characterization of a Cauchy matrix. To do so, we introduce the notion of a Cauchy pair. A Cauchy pair is an ordered pair of diagonalizable linear transformations ( X , X ˜ ) on a finite-dimensional vector space V such that X − X ˜ has rank 1 and such that there does not exist a proper subspace W of V such that X W ⊆ W and X ˜ W ⊆ W . Let V denote a vector space over K with dimension | X | . We show that for every Cauchy pair ( X , X ˜ ) on V , there exists an X -eigenbasis { v i } i ∈ X for V and an X ˜ -eigenbasis { w i } i ∈ X for V such that the transition matrix from { v i } i ∈ X to { w i } i ∈ X is Cauchy. We show that every Cauchy matrix arises as a transition matrix for a Cauchy pair in this way. We give a bijection between the set of equivalence classes of Cauchy pairs on V and the set of permutation equivalence classes of Cauchy matrices in Mat X ( K ) .
An asymptotic determination of the minimum spanning tree and minimum matching constants in geometrical probability

Given n uniformly and independently distributed points in a ball of unit volume in dimension d, it is well established that the length of several combinatorial optimization problems (including the minimum spanning tree (MST), the minimum matching (M), the travelling salesman problem (TSP), etc.) on these n points is asymptotic to @b(d)n^(^d^-^1^)^/^d, where the constant @b(d) for these problems. In this paper progress is made in establishing the constants @b"M"S"T(d), @b"M(d) for the MST and the matching problem. By applying Crofton's method, an old method in geometrical probability, it is proved that @b"M"S"T(d)[email protected]/d/([email protected], @b"M(d)[email protected]/d/([email protected]) as d tends to infinity. Moreover, the method presented here corresponds to heuristics for these problems, which are asymptotically exact as the dimension increases. Finally, the asymptotics for the TSP constant are examined.
Relax, No Need to Round: Integrality of Clustering Formulations

We study exact recovery conditions for convex relaxations of point cloud clustering problems, focusing on two of the most common optimization problems for unsupervised clustering: k-means and k-median clustering. Motivations for focusing on convex relaxations are: (a) they come with a certificate of optimality, and (b) they are generic tools which are relatively parameter-free, not tailored to specific assumptions over the input. More precisely, we consider the distributional setting where there are k clusters in Rm and data from each cluster consists of n points sampled from a symmetric distribution within a ball of unit radius. We ask: what is the minimal separation distance between cluster centers needed for convex relaxations to exactly recover these k clusters as the optimal integral solution? For the k-median linear programming relaxation we show a tight bound: exact recovery is obtained given arbitrarily small pairwise separation e > O between the balls. In other words, the pairwise center separation is δ > 2+e. Under the same distributional model, the k-means LP relaxation fails to recover such clusters at separation as large as δ = 4. Yet, if we enforce PSD constraints on the k-means LP, we get exact cluster recovery at separation as low as δ > min{2 + √2k/m}, 2+√2 + 2/m} + e. In contrast, common heuristics such as Lloyd's algorithm (a.k.a. the k means algorithm) can fail to recover clusters in this setting; even with arbitrarily large cluster separation, k-means++ with overseeding by any constant factor fails with high probability at exact cluster recovery. To complement the theoretical analysis, we provide an experimental study of the recovery guarantees for these various methods, and discuss several open problems which these experiments suggest.
The hyperdeterminant and triangulations of the 4-cube

PETER HUGGINS, BERND STURMFELS,JOSEPHINE YU AND DEBBIE S. YUSTERAbstract. The hyperdeterminant of format 2×2×2×2 is a polynomialof degree 24 in 16 unknowns which has 2894276 terms. We compute theNewton polytope of this polynomial and the secondary polytope of the 4-cube. The 87959448 regular triangulations of the 4-cube are classiﬁed into25448 D-equivalence classes, one for each vertex of the Newton polytope.The 4-cube has 80876 coarsest regular subdivisions, one for each facet of thesecondary polytope, but only 268 of them come from the hyperdeterminant.
Synthesis of asymmetric septi-(p-phenylene)s

In this Letter, we describe the synthesis of two amphiphilic septi(p-phenylene)s. One terminus of each rigid-rod scaffold is linked through a spacer to a hydrophilic IDA-subunit, the two benzenes at the other terminus carry hydrophobic substituents of different size. These synthetic receptor models are expected to mimic biological processes that occur at cell membranes.
Acoustically modulated electrical impedance tomography

The feasibility of a new diagnostic imaging technique is investigated that potentially might be used for breast cancer screening with millimeter resolution, but without using ionizing radiation. It is suggested that acoustic pulses of sufficient intensity may produce small density changes within tissue which result in small but detectable changes in electrical current flowing through the tissue. The magnitude of this current fluctuation is shown to be inversely proportional to the conductivity of the tissue within the region occupied by the pulse. Measurement of the current modulation may enable small resistive inhomogeneities, such as tumors, to be detected. If the position of a pulse's wavefront can be predicted with sufficient precision at any given instant, measurement of the current modulation could be used to reconstruct the unknown electrical impedance distribution within the tissue. The rudiments of the technique are discussed and, using some simplifying assumptions, a rough estimate is made of the magnitude of the current modulation, and of the timescale necessary to obtain useful diagnostic information.
Dimensions of learning in a real-time knowledge-based control system

Abstract We first describe and justify the domain in which cooperating and learning real-time distributed expert systems perform control operations of urban street traffic signals. We then present the general design of the ultimate system as well as the simplifying assumptions used in a running prototype. The latter, proving the technical feasibility of the approach, has attained a 42% improvement in the traffic flow under non-saturated conditions. Finally, we draw some conclusions concerning the methodology of distributed planning and problem solving systems.
Aluminum-catalyzed enantio- and diastereoselective carbonyl addition of propargylsilanes. A new approach to enantioenriched vinyl epoxides.

A new pathway involving a Lewis acid-catalyzed carbonyl addition reaction of propargylsilanes and its subsequent development into a general enantio- and diastereoselective process are described. Aliphatic propargylsilanes with both saturated and unsaturated sidechains were effective nucleophiles affording highly functionalized chiral vinyl epoxides in good enantioselectivities (85−94% ee), excellent diastereoselectivities (>99:1 E:Z; >99:1 anti:syn) and in moderate to good yields (49−97%).
Are Allenes with Zwitterionic Character Still Allenes? Of Course!

Der wahre Grundzustand von 1 ist Gegenstand der Debatte, zum Zweck einer klaren und einfachen Beschreibung ist aber die allenische Resonanzform 1 a am zweckdienlichsten. Es wird gezeigt, dass die Argumente, die Christl und Engels bezuglich der Aromatizitat dieser Spezies anfuhren, inkorrekt sind.
More is more: The benefits of denser sensor deployment

Positioning disk-shaped sensors to optimize certain coverage parameters is a fundamental problem in ad hoc sensor networks. The hexagon lattice arrangement is known to be optimally efficient in the plane, even though 20.9p of the area is unnecessarily covered twice, however, the arrangement is very rigid—any movement of a sensor from its designated grid position (due to, e.g., placement error or obstacle avoidance) leaves some region uncovered, as would the failure of any one sensor. In this article, we consider how to arrange sensors in order to guarantee multiple coverage, that is, k-coverage for some value k > 1. A naive approach is to superimpose multiple hexagon lattices, but for robustness reasons, we may wish to space sensors evenly apart.We present two arrangement methods for k-coverage: (1) optimizing a Riesz energy function in order to evenly distribute nodes, and (2) simply shrinking the hexagon lattice and making it denser. The first method often approximates the second, and so we focus on the latter. We show that a density increase tantamount to k copies of the lattice can yield k′-coverage, for k′ > k (e.g., k = 11, k′ = 12 and k = 21, k′ = 24), by exploiting the double-coverage regions. Our examples' savings provably converge in the limit to the a 20.9p maximum. We also provide analogous results for the square lattice and its a 57p inefficiency (e.g., k = 3, k′ = 4 and k=5, k′ = 7) and show that for multi-coverage for some values of k′, the square lattice can actually be more efficient than the hexagon lattice.We also explore other benefits of shrinking the lattice: Doing so allows all sensors to move about their intended positions independently while nonetheless guaranteeing full coverage and can also allow us to tolerate probabilistic sensor failure when providing 1-coverage or k-coverage. We conclude by construing the shrinking factor as a budget to be divided among these three benefits.
THE MISPRICING OF ABNORMAL ACCRUALS

This paper examines the market pricing of Jones (1991) modelestimated abnormal accruals (often termed “discretionary accruals” in the prior literature) to test whether stock prices rationally reflect the one‐year‐ahead earnings implications of these accruals. Using the Mishkin (1983) and hedge‐portfolio test methods Sloan (1996) employs, I find that the market overestimates the persistence, or one‐year‐ahead earnings implications, of abnormal accruals, and consequently overprices these accruals. These results extend Subramanyam (1996) by demonstrating that the market not only prices, but also overprices abnormal accruals. They also suggest that the overpricing of total accruals that Sloan (1996) documents is due largely to abnormal accruals. The results are robust to five alternative measures of abnormal accruals, and still hold when I estimate abnormal accruals after controlling for major unusual but largely nondiscretionary accruals. The latter finding is consistent with the notion that the market overp...
A dynamic model of cross-category competition: theory, tests and applications.

Abstract Recent marketing studies use scanner data to diagnose the influence of a change in a brand's marketing mix on other brands in the same category. A few studies also use scanner data to model inter-category effects between substitutes (e.g., tea and coffee) or complements (e.g., tea and sugar). No study models the dynamic effects of cross-category competition though. We present a dynamic model that shows how different products in a typical market basket influence demand of one another. Empirical tests use single-source, market-level data for ice cream and some substitute and complement categories. On the basis of in-sample fit, out-of-sample forecasts, and formal causality tests, this study demonstrates that the marketing mix decisions for ice cream influence the sales and market shares of ice cream toppings and frozen yogurt. As a check on the predictive validity of the model, model parameters, using 16-month data, predict behavior in the subsequent 3 months.
Three-dimensional boundary-layer flow over a flat delta wing at a moderate angle of attack.

This is a study of the three-dimensional boundary layer over the windward side of a flat delta wing in hypersonic flow at a moderate angle of attack. The interaction between the inviscid and the viscous flow regions is analyzed, and its effect is taken into account. The theory is developed for thin, flat delta wings with the shock detached from the leading edges and attached at the apex. The inviscid solution based on the Newtonian-conical flow theory of Messiter-Hida has been matched to the three-dimensional boundary-layer solution over the wing. The transverse velocity component normal to the conical ray is small, and a perturbation method leads to a system of ordinary differential equations. The solution of these equations together with the tangent-cone method is used to study the viscous-inviscid interaction. The results are applied to calculate the streamline pattern, induced pressure, skin drag, and heat transfer over the wing surface. The present theory is in general agreement with the available experimental data.
Distributions of nonsupersymmetric flux vacua

We continue the study of the distribution of nonsupersymmetric flux vacua in IIb string theory compactified on Calabi-Yau manifolds, as in hep-th/0404116. We show that the basic structure of this problem is that of finding eigenvectors of the matrix of second derivatives of the superpotential, and that many features of the results are determined by features of the generic ensemble of such matrices, the CI ensemble of Altland and Zirnbauer originating in mesoscopic physics. We study some simple examples in detail, exhibiting various factors which can favor low or high scale supersymmetry breaking.
The production of “braids” in Saturn's F ring

The 'braided' structure noted in Voyager images of the Saturn F ring is presently addressed by two models. In the first, the pattern is generated by a narrow and initially uniform ring's passing of a nearby satellite, followed by an embedded moonlet gravitational acceleration-induced doubling back so that trajectories of the ring particles traverse one end of the classic 'horseshoe' orbit. In the second model, the F ring is composed of two separated strands before the moon's passage, so that a long braided pattern can be generated by the subsequent drift in relative phase; the embedded moonlet is thereby obviated.
Correlation functions of the one-dimensional Hubbard model in a magnetic field.

We present a general method for the calculation of correlation functions in the repulsive one-dimensional Hubbard model at less than half-filling in a magnetic field h. We describe the dependence of the critical exponents that drive their long-distance asymptotics on the Coulomb coupling, the density, and h. This dependence can be described in terms of a set of coupled Bethe-Ansatz integral equations. It simplifies significantly in the strong-coupling limit, where we give explicit formulas for the dependence of the critical exponents on the magnetic field. In particular, we find that at small field the functional dependence of the critical exponents on h can be algebraic or logarithmic---depending on the operators involved. In addition, we evaluate the singularities of the Fourier images of the correlation functions. It turns out that switching on a magnetic field gives rise to singularities in the dynamic field-field correlation functions that are absent at h=0.
Phase messaging method for time-of-flight cameras

Ubiquitous light emitting devices and low-cost commercial digital cameras facilitate optical wireless communication system such as visual MIMO where handheld cameras communicate with electronic displays. While intensity-based optical communications are more prevalent in camera-display messaging, we present a novel method that uses modulated light phase for messaging and time-of-flight (ToF) cameras for receivers. With intensity-based methods, light signals can be degraded by reflections and ambient illumination. By comparison, communication using ToF cameras is more robust against challenging lighting conditions. Additionally, the concept of phase messaging can be combined with intensity messaging for a significant data rate advantage. In this work, we design and construct a phase messaging array (PMA), which is the first of its kind, to communicate to a ToF depth camera by manipulating the phase of the depth camera's infrared light signal. The array enables message variation spatially using a plane of infrared light emitting diodes and temporally by varying the induced phase shift. In this manner, the phase messaging array acts as the transmitter by electronically controlling the light signal phase. The ToF camera acts as the receiver by observing and recording a time-varying depth. We show a complete implementation of a 3×3 prototype array with custom hardware and demonstrating average bit accuracy as high as 97.8%. The prototype data rate with this approach is 1 Kbps that can be extended to approximately 10 Mbps.
Composition Measurements of a Comet from the Rosetta Orbiter Spacecraft

The European Space Agency (ESA) Rosetta Spacecraft, launched on March 2, 2004 toward Comet 67P/Churyumov-Gerasimenko (C-G), carries a complementary set of instruments on both the orbiter and lander (Philae) portions of the spacecraft, to measure the composition of the Comet C-G. The primary composition measuring instruments on the Orbiter are Alice, COSIMA, ICA, MIRO, OSIRIS, ROSINA and VIRTIS. These instruments collectively are capable of providing compositional information, including temporal and spatial distributions of important atomic, molecular, and ionic species, minerals, and ices in the coma and nucleus. The instruments utilize a variety of techniques and wavelength ranges to accomplish their objectives. This paper provides an overview of composition measurements that will be possible using the suite of orbiter composition measuring instruments. A table is provided that lists important species detectable (depending on abundances) with each instrument.
New Bounds on Crossing Numbers

The crossing number, cr(G), of a graph G is the least number of crossing points in any drawing of G in the plane. Denote by ? (n, e) the minimum of cr(G) taken over all graphs with n vertices and at least e edges. We prove a conjecture of Erd?s and Guy by showing that ? (n, e)n 2/e 3 tends to a positive constant as n ? ? and n ? e ? n 2. Similar results hold for graph drawings on any other surface of fixed genus. We prove better bounds for graphs satisfying some monotone properties. In particular, we show that if G is a graph with n vertices and e ? 4n edges, which does not contain a cycle of length four (resp. six), then its crossing number is at least ce 4/n 3 (resp. ce 5/n 4), where c > 0 is a suitable constant. These results cannot be improved, apart from the value of the constant. This settles a question of Simonovits.
An auroral X-ray imaging spectrometer

A scanning X-ray spectrometer was flown aboard the United States Air Force Defense Meteorological Satellite Program (DMSP-F6) satellite to image X-ray production in the earth's atmosphere. One of the main objectives of this experiment was to image auroral signatures associated with electron precipitation at energies above a few keV. A brief description of the instrument is given and a sequence of auroral images is shown to demonstrate on-orbit performance and to illustrate the use of such data to monitor ionization density perturbations in the earth's atmosphere.
Solar cycle variations in the elemental abundance of helium and fractionation of iron in the fast solar wind: Indicators of an evolving energetic release of mass from the lower solar atmosphere

We present and discuss the strong correspondence between evolution of the emission length scale in the lower transition region and in situ measurements of the fast solar wind composition during the most recent solar minimum. We combine recent analyses demonstrating the variance in the (supergranular) network emission length scale measured by the Solar and Heliospheric Observatory (and STEREO) with that of the helium abundance (from Wind) and the degree of iron fractionation in the solar wind (from the Advanced Composition Explorer and Ulysses). The net picture developing is one where a decrease in the helium abundance and the degree of iron fractionation (approaching values expected of the photosphere) in the fast wind indicate a significant change in the process loading material into the fast solar wind during the recent solar minimum. This result is compounded by a study of the helium abundance during the space age using the NASA OMNI database, which shows a slowly decaying amount of helium being driven into the heliosphere over the course of several solar cycles.
Rectal biopsy in ulcerative colitis.

We have studied 271 rectal biopsy specimens from 236 cases of ulcerative colitis. The value of such biopsies is twofold. Arising out of this study we have been stimulated to investigate the appearances of the early lesions of the disease and this again has provided two fields of interest. First, the study of morphologic changes and second, the realization that the presence of skip areas and early lesions in parts of the colon which may otherwise be regarded as being normal must in some degree determine the extent of the operation most suitable when surgical intervention is contemplated.
Analysis of bulk DKDP damage distribution, obscuration, and pulse-length dependence

Recent LLNL experiments reported elsewhere at this conference explored the pulse length dependence of 351 nm bulk damage incidence in DKDP. The results found are consistent, in part, with a model in which a distribution of small bulk initiators is assumed to exist in the crystal, and the damage threshold is determined by reaching a critical temperature. The observed pulse length dependence can be explained as being set by the most probable defect capable of causing damage at a given pulse length. Analysis of obscuration in side illuminated images of the damaged region yields estimates of the damage site distributions that are in reasonable agreement with the distributions experimentally directly estimated.
A trainable approach for multi-lingual speech-to-speech translation system

This paper presents a statistical speech-to-speech machine translation (MT) system for limited domain applications using a cascaded approach. This architecture allows for the creation of multilingual applications. In this paper, the system architecture and its components, including the speech recognition, parsing, information extraction, translation, natural language generation (NLG) and text-to-speech (TTS) components are described. We have implemented the described system for translating speech between Mandarin and English language pair in an air travel application domain. We are current porting the system to the military domain. Encouraging experimental results have been observed and are presented.
Supersymmetry at linear colliders: the importance of being e-e

Advantages of the e-e- option at linear colliders for the study of supersymmetry are highlighted. The fermion number violating process provides unique opportunities for studies of slepton masses and flavor mixings. In particular, slepton mass measurements at the 100 MeV level through threshold scans of scalar pair production may be possible. Such measurements are over an order of magnitude better than those possible in e+e- mode, require far less integrated luminosity, and may lead to precise, model-independent measurements of tan β. Implications for studying gauginos and the importance of accurate beam polarimetry are also discussed.
Invertible Carnot Groups

In this talk we will investigate properties of homogeneous metric spaces that can be “metrically inverted.” A metric inversion generalizes the usual notion of a Mobius inversion in Euclidean space. In particular, we will characterize Carnot groups that admit a metric inversion.
Spin dynamics of double-exchange manganites with magnetic frustration

This work examines the effects of magnetic frustration due to competing ferromagnetic and antiferromagnetic Heisenberg interactions on the spin dynamics of the double-exchange model. When the local moments are noncolinear, a charge-density wave forms because the electrons prefer to sit on lines of sites that are coupled ferromagnetically. With increasing hopping energy, the local spins become aligned and the average spin-wave stiffness increases. Phase separation is found only within a narrow range of hopping energies. Results of this work are applied to the field-induced jump in the spin-wave stiffness observed in the manganite ${\mathrm{Pr}}_{1\ensuremath{-}x}{\text{Ca}}_{x}{\text{MnO}}_{3}$ with $0.3\ensuremath{\leqslant}x\ensuremath{\leqslant}0.4$.
Hypervelocity Stars: Predicting the Spectrum of Ejection Velocities

The disruption of binary stars by the tidal field of the black hole in the Galactic center can produce the hypervelocity stars observed in the halo. We use numerical models to simulate the full spectrum of observable velocities of stars ejected into the halo by this binary disruption process. Our models include a range of parameters for binaries with 3-4 M☉ primaries, consideration of radial orbits of the ejected stars through an approximate mass distribution for the Galaxy, and the impact of stellar lifetimes. We calculate the spectrum of ejection velocities and reproduce previous results for the mean ejection velocity at the Galactic center. The model predicts that the full population of ejected stars includes both the hypervelocity stars with velocities large enough to escape from the Galaxy and a comparable number of ejected, but bound, stars of the same stellar type. The predicted median speeds of the population of ejected stars as a function of distance in the halo are consistent with current observations. Combining the model with the data also shows that interesting constraints on the properties of binaries in the Galactic center and on the mass distribution in the Galaxy can be obtained even with modest samples of ejected stars.
Enantioselective Synthesis of γ-Hydroxyenones by Chiral Base-Catalyzed Kornblum DeLaMare Rearrangement

A cinchona−alkaloid catalyzed asymmetric Kornblum DeLaMare rearrangement has been developed. Thus, enantioenriched 4-hydroxyenones are prepared from dienes by a two-step sequence involving photochemical dioxygenation and chiral base-catalyzed desymmetrization of the resulting endoperoxides.
CRITICAL BEHAVIOR OF STRONGLY COUPLED LATTICE QCD AT FINITE TEMPERATURE

We study the critical behavior of lattice Quantum Chromodynamics (QCD) in the strong coupling approximation with Kogut–Susskind and Wilson fermions at finite temperature (T) and zero chemical potential. Using the Hamiltonian formulation we construct a mean field solution to the equation of motion at finite T and use it to study the elementary thermal excitations and to extract some critical exponents characterizing the observed second-order phase transition. We find similar critical behaviors for Kogut–Susskind and Wilson fermions at finite T.