cssi/SciSciGPT-SciSciNet huggingface dataset:
Saving phase: Injectivity and stability for phase retrieval

Abstract Recent advances in convex optimization have led to new strides in the phase retrieval problem over finite-dimensional vector spaces. However, certain fundamental questions remain: What sorts of measurement vectors uniquely determine every signal up to a global phase factor, and how many are needed to do so? Furthermore, which measurement ensembles yield stability? This paper presents several results that address each of these questions. We begin by characterizing injectivity, and we identify that the complement property is indeed a necessary condition in the complex case. We then pose a conjecture that 4 M − 4 generic measurement vectors are both necessary and sufficient for injectivity in M dimensions, and we prove this conjecture in the special cases where M = 2 , 3 . Next, we shift our attention to stability, both in the worst and average cases. Here, we characterize worst-case stability in the real case by introducing a numerical version of the complement property. This new property bears some resemblance to the restricted isometry property of compressed sensing and can be used to derive a sharp lower Lipschitz bound on the intensity measurement mapping. Localized frames are shown to lack this property (suggesting instability), whereas Gaussian random measurements are shown to satisfy this property with high probability. We conclude by presenting results that use a stochastic noise model in both the real and complex cases, and we leverage Cramer–Rao lower bounds to identify stability with stronger versions of the injectivity characterizations.
Down with Dullness: Gaming the Academic Conference

It is a truism among academics that most of the creative work at a conference happens outside the formal sessions, at social gatherings. If this is so, why not drop the formal sessions entirely? In this article, I propose a method for making an entire conference into a formalized social gathering, with a structure that both encourages the exchange of ideas and also records the evolution of thought. In this method, named “Ludium,” games replace presentations as the unifying element. Theme-appropriate games unlock creative juices and allow for soft entry points for networking. A conference meta-game elicits common views about the standing of ideas. A rapid review session concludes the conference and summarizes major points. Past experience with conferences in this vein indicates that indeed a great deal of solid academic work gets done. Moreover, everyone has fun, and the results of the conference, the “sense of the group,” can easily and immediately be broadcast to the public. All of these outcomes stand in stark contrast to the outcome of typical academic conferences.
Prescribing Authority During Emergencies: Challenges for Mental Health Care Providers

The short- and long-term consequences of natural and man-made disasters present unique challenges for those who work to protect the public's health. Lessons learned from emergencies, including the ...
Problems In Solar Irradiance Measurements

A number of areas of current research interest require measurements of solar irradiance made with greater absolute accuracy than is currently being achieved at various monitoring sites. By using currently available instrumentation and careful measuring techniques it is shown that it is possible to measure the solar irradiance with considerable precision on a routine basis. The major problem that re-mains is making the measurements absolute; and an investigation of the standards used in pyrheliometry is required before a significant increase in absolute accuracy can be obtained.© (1976) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Link-state based decode-forward schemes for two-way relaying

In this paper, we analyze a composite decode-and-forward scheme for the two-way relay channel with a direct link. During transmission, our scheme combines both block Markov coding and an independent coding scheme similar to network coding at the relay. The main contribution of this work is to examine how link state impacts the allocation of power between these two distinct techniques, which in turn governs the necessity of each technique in achieving the largest transmission rate region. We analytically determine the link-state regimes and associated relaying techniques. Our results illustrate an interesting trend: when the user-to-relay link is marginally stronger than the direct link, it is optimal to use only independent coding. In this case, the relay need not use full power. However, for larger user-to-relay link gains, the relay must supplement independent coding with block Markov coding to achieve the largest rate region. These link-state regimes are important for the application of two-way relaying in 5G networks, such as in D2D mode or relay-aided transmission.
Unconventional promoters of catalytic activity in electrocatalysis

Promoters and poisons for catalytic activity have been a subject of intensive research in both heterogeneous catalysis and electrocatalysis for decades, driven primarily by profound financial and societal implications involved because catalyzed reactions are at the center of many enterprises of chemical and petroleum industries. Consequently, there exist well-identified promoters and poisons, such as electropositive alkali elements for the former and electronegative later 2p elements for the latter, respectively. Research on catalytic promoters or poisons has traditionally been along the lines of these conventional classifications of promoters vs. poisons. However, this short Critical Review will not follow such traditional lines of reasoning, i.e., to discuss how the well-identified promoters can be better utilized and/or how the equally well-identified poisons can be eliminated or better tolerated. Rather, it will focus on cases that highlight an emerging area of research in which many traditional poisoning species have been used to promote catalytic activity, which include recent work on using sulfur and poly(vinylpyrrolidone) (PVP) as catalytic promoters carried out in the author’s lab.
Turbulence indicators for Space Shuttle launches

A report on the research and analysis for identifying turbulent regions from the surface to 16 km for Space Shuttle launches is presented. The research demonstrates that the results from the FPS-16 radar/jimsphere balloon system in measuring winds can indicate the presence of or conditions ripe for turbulence in the troposphere and lower stratosphere. It is shown that atmospheric data obtained during the Shuttle launches by the rawinsonde in conjunction with the jimsphere provide the necessary meteorological data to compute aerodynamic parameters to identify turbulence.
Clusters of galaxies: a cosmological probe.

The constraints on cosmological parameters presently obtained and those that can be obtained from X–ray cluster surveys are presented. Extremely strong bounds on the values of Ω, λ, σ 8 and the power spectrum of fluctuations, as well as constraints on the equation of state of dark energy, can be determined. Recent Advanced Satellite for Cosmology and Astrophysics and XMM results on the chemical composition of clusters show that the Fe abundance is not universal, but is correlated with cluster mass and central gas density. The Si, S and Fe abundances do not resemble those seen in Milky Way Halo stars or those in the Lyman–limit galaxies. The XMM RGS abundances for gas in elliptical galaxies are subsolar and the abundance pattern is not alpha–element rich, in contradiction with all models of elliptical–galaxy gas abundances.
Simpler Session-Key Generation from Short Random Passwords

Goldreich and Lindell (CRYPTO ’01) recently presented the first protocol for password-authenticated key exchange in the standard model (with no common reference string or set-up assumptions other than the shared password). However, their protocol uses several heavy tools and has a complicated analysis. We present a simplification of the Goldreich–Lindell (GL) protocol and analysis for the special case when the dictionary is of the form $\mathcal{D}=\{0,1\}^{d}$ i.e., the password is a short string chosen uniformly at random (in the spirit of an ATM PIN number). The security bound achieved by our protocol is somewhat worse than the GL protocol. Roughly speaking, our protocol guarantees that the adversary can “break” the scheme with probability at most $O(\mathrm{poly}(n)/|\mathcal{D}|)^{\Omega(1)}$, whereas the GL protocol guarantees a bound of $O(1/|\mathcal{D}|)$. We also present an alternative, more natural definition of security than the “augmented definition” of Goldreich and Lindell, and prove that the two definitions are equivalent.
Unanticipated money, output, and prices in the small economy

Abstract Recent studies of the relationship between unanticipated monetary disturbances and the level of output and prices have focussed on the implications of monetary policy for the large, essentially closed, economy. This paper investigates the determination of output, the price level, and the money stock of a small open economy. In particular, primary interest is in delineating the channels of home and foreign monetary influence, and in discriminating between the effects of home-generated and foreign-generated unanticipated monetary disturbances under the alternative regimes of a fixed, managed, and flexible exchange rate.
La investigación en acción: una guía práctica

ResumenEste articulo presenta los rasgos generales que definen la investigacion en accion en el campo educativo. Primero, se sugieren razones para explicar el mayor interes por este modelo de analisis en los ultimos veinte anos, seguidas por diferentes versiones del concepto de investigacion en accion. A continuacion, se presenta un modelo de analisis acompanado de un esquema de trabajo cuya realizacion dependera de los objetivos especificos, el numero de participantes y los medios de que se disponga. Finalmente, el articulo situa la investigacion en accion en el marco de una actitud critica ante las innovaciones pedagogicas basadas en aspectos puramente teoricos.
Silicon-initiated carbonylative carbotricyclization and [2+2+2+1] cycloaddition of enediynes catalyzed by rhodium complexes

The reaction of dodec-11-ene-1,6-diynes or their heteroatom congeners with a hydrosilane catalyzed by Rh(acac)(CO)2 at ambient temperature and pressure of CO gives the corresponding fused 5-7-5 tricyclic products, 5-oxo-1,3a,4,5,7,9-hexahydro-3H-cyclopenta[e]azulenes or their heteroatom congeners, in excellent yields through a unique silicon-initiated cascade carbonylative carbotricyclization (CO-SiCaT) process. It has also been found that the 5-7-5 fused tricyclic products can be obtained from the same type of enediynes and CO through a novel intramolecular [2+2+2+1] cycloaddition process. The characteristics of these two tricyclization processes and the fundamental differences in their reaction mechanisms are discussed. This novel higher-order cycloaddition reaction has also been successfully applied to the tricyclization of undeca-5,10-diyn-1-als, affording the corresponding 5-7-5 fused-ring products bearing a seven-membered lactone moiety. Related [2+2+2] tricyclizations of enediyne and diynal substrates are also discussed. These newly discovered reactions can construct multiple bonds all at once, converting linear starting materials to polycyclic compounds in a single step. Thus, these new processes provide innovative routes to functionalized polycyclic compounds that are useful for the syntheses of natural and unnatural products.
A collaborative systems approach to rural burn care.

A collaborative systems approach was created between the regional verified burn center (BC) and the rural verified Level 1 trauma center (TC) to treat minor burns. This study assesses the feasibility of providing outpatient burn care at the TC. A retrospective review was performed from January 2000 to June 2005 of burn patients seen at the TC. Seven trauma/critical care surgeons and a dedicated burn nurse staffed the clinic twice a week. Burn surgeons from the BC provided consultation via email and telephone links and served as the regional resource. In the TC clinic, 314 injuries occurred in 311 patients. 196 patients were male with an average age of 34.5 +/- 1.1 years. The mean burn TBSA was 2.9 +/- 0.2%. Fourteen patients (4%) required skin grafts. Patients averaged 3.5 +/- 0.1 clinic visits over a mean follow-up period of 42.9 +/- 7.4 days from initial injury. There were 1252 scheduled appointments during the study period. Silver sulfadiazine or triple antibiotic ointment was applied in the majority of the cases. Thirty-one patients (9.9%) were documented to have complications, most of which were local wound infections. Long-term sequelae (scarring, chronic pain, and contractures) occurred in 13.4% of patients. Clinical success in outpatient burn care can be achieved at a non burn center with dedicated personnel. The successful collaboration between the BC and TC can unload some minor burn care from the burn center, while providing good clinical care to the local rural population. Language: en
An undergraduate rootkit research project: How available? How hard? How dangerous?

A rootkit is a small, hard to detect computer program that stealthily invades an operating system or kernel and takes control of the computer. The rootkit can be placed on a computer by a hacker that gains unauthorized access to a computer, or by an unsuspecting authorized user that allows a virus or other malicious software to insert the rootkit into their computer. Cyberspace is full of threats and risks. Each danger must be carefully considered and protected against only to the extent that is reasonable and affordable in accordance with a prudent risk management program. When considering rootkits a risk manager will ask: How common are they? How severe are the consequences? How can they be prevented? How can they be removed? These general questions have been explored in a number of research projects and publications. At a finer level of detail and on a recurring basis, information assurance managers will also ask 'as of right now': How hard are they to create? How available is rootkit source code? How hard are they to install and operate? This paper describes a research project at Murray State University in which faculty and senior undergraduate students explored this second set of more time-sensitive questions. It describes both the pedagogical and technical issues of having students find rootkit source code on the web; getting the source code to run and operate in an academic laboratory without threatening the university's IT environment; and exploring what tools and techniques are currently available for detecting and removing rootkits.
E-Karaoke Learning for Gender Empowerment in Rural India

A folksongs karaoke product has been created to increase usage of subtitled media to enhance literacy and technology use, particularly among girls in rural India. This entails generating and proliferating popular local folksongs with social and cultural themes of interest to girls, accompanied by the award-winning Same Language Subtitling (SLS) feature. In this paper, the prime goal is to discuss possible implications of this novel technology content on girls' socialization, education, and activism. Based on initial findings from a pilot test of this product in schools, private and public in rural India, I propose that this product has the potential to raise literacy among girls through musical enculturation and entertainment in rural India. By linking folksongs to computers, I argue that this association can shape, transform and/or (re)configure spaces for/by girls in rural India through interaction with technology in ways meaningful to them. Thereby, I problematize the transposition of "western" perspectives of gender and technology onto the rural terrain as understood within a development discourse.
Distribution of Missing Sums in Sumsets

For a finite set of integers X, define its sumset X+X to be {x+y:x, y∈X}. In a recent paper, Martin and O’Bryant investigated the distribution of |A+A| given the uniform distribution on subsets A⊆{0, 1, … , n−1}. They also conjectured the existence of a limiting distribution for |A+A| and showed that the expectation of |A+A| is . Zhao proved that the limits exist, and that ∑ k⩾0 m(k)=1. We continue this program and give exponentially decaying upper and lower bounds on m(k), and sharp bounds on m(k) for small k. Surprisingly, the distribution is at least bimodal; sumsets have an unexpected bias against missing exactly seven sums. The proof of the latter is by reduction to questions on the distribution of related random variables, with large-scale numerical computations a key ingredient in the analysis. We also derive an explicit formula for the variance of |A+A| in terms of Fibonacci numbers, finding that . New difficulties arise in the form of weak dependence between events of the form {x∈A+A}, {y∈A+A}. W...
Cassini Thruster Calibration Algorithm Using Reaction Wheel Biasing Data

Thrust force estimates for the reaction control thrusters onboard the Cassini spacecraft are presented in this paper. Cassini consists of two thruster branches, each with eight thrusters. The eight thrusters in each branch control the three body-fixed axes of the spacecraft. It is important to track the thrust force estimates in order to detect any thruster degradation and for supporting various activities in spacecraft operations (Titan flyby, spacecraft maneuvers, etc.). The Euler equation, which describes the rotational motion of the spacecraft during a reaction wheel bias event (wheel momentum change), is used to develop the algorithm. The thrust estimates are obtained from the pseudoinverse solution using flight telemetry during the bias. These results are similar to thrust estimates from the Kalman filtering algorithm. Cassini operations used the first thruster branch from launch until November 2008. Results show that two thrusters in this branch exhibited degraded thrust in November 2008. Because o...
Generalizations of generating functions for hypergeometric orthogonal polynomials with definite integrals

Abstract We generalize generating functions for hypergeometric orthogonal polynomials, namely Jacobi, Gegenbauer, Laguerre, and Wilson polynomials. These generalizations of generating functions are accomplished through series rearrangement using connection relations with one free parameter for these orthogonal polynomials. We also use orthogonality relations to determine corresponding definite integrals.
The Hydrodynamics of Gamma-ray Burst Remnants

This paper reports on the results of a numerical investigation designed to address how the initially anisotropic appearance of a gamma-ray burst (GRB) remnant is modified by the character of the circumburst medium and by the possible presence of an accompanying supernova (SN). Axisymmetric hydrodynamical calculations of light, impulsive jets propagating in both uniform and inhomogeneous external media are presented, which show that the resulting dynamics of their remnants since the onset of the non-relativistic phase is different from the standard self-similar solutions. Because massive star progenitors are expected to have their close-in surroundings modified by the progenitor winds, we consider both free winds and shocked winds as possible external media for GRB remnant evolution. Abundant confirmation is provided here of the important notion that the morphology and visibility of GRB remnants are determined largely by their circumstellar environments. For this reason, their detectability is highly biased in favor of those with massive star progenitors; although, in this class of models, the beamed component may be difficult to identify because the GRB ejecta is eventually swept up by the accompanying SN. The number density of asymmetric GRB remnants in the local universe could be, however, far larger if they expand in a tenuous interstellar medium, as expected for some short GRB progenitor models. In these sources, the late size of the observable, asymmetric remnant could extend over a wide, possibly resolvable angle and may be easier to constrain directly.
Bounds on eigenvalues of finite element systems

Bounds on eigenvalues of various finite element systems are analysed by using an element eigenvalue theorem together with the Global Eigenvalue Theorem. Both two dimensional continuum dynamics and heat conduction problems are considered. These bounds provide stable time steps for explict time integration schemes. A reduced eigenproblem at element quadrature point level, with all zero eigenvalues suppressed, is also presented in this paper. The simplified eigenproblem results in simple formulas for calculating the eigenvalues.
Driving oxygen coordinated ligand exchange at nanocrystal surfaces using trialkylsilylated chalcogenides

A general, efficient method is demonstrated for exchanging native oxyanionic ligands on inorganic nanocrystals with functional trimethylsilylated (TMS) chalcogenido ligands. In addition, newly synthesized TMS mixed chalcogenides leverage preferential reactivity of TMS–S bonds over TMS–O bonds, enabling efficient transfer of luminescent nanocrystals into aqueous media with retention of their optical properties.
Non-perturbative effects of geometry in wide-angle redshift distortions

We use the formalism of Szapudi to derive full explicit expressions for the linear two-point correlation function, including redshift-space distortions and large angle effects. We take into account a non-perturbative geometric term in the Jacobian, which is still linear in terms of the dynamics. This term had been identified previously, but has been neglected in all subsequent explicit calculations of the linear redshift-space two-point correlation function. Our results represent a significant correction to previous explicit expressions and are in excellent agreement with our measurements in the Hubble volume simulation.
Unusual course of the chromate oxidation of secododecahedrene and its monoepoxide

Secododecahedrene (5) and its epoxide derivative 6 are both transformed by sodium chromate and acetic acid/acetic anhydride into the C2-symmetric product 7 via an unusually regiospecific and unprecedented oxidative process.
Numerical Computations of Transonic Critical Aerodynamic Behavior

The determination of aerodynamic coefficients by shell designers is a critical step in the development of any new projectile design. Of particular interest is the determination of the aerodynamic coefficients at transonic speeds. It is in this speed regime that the critical aerodynamic behavior occurs and a rapid change in the aerodynamic coefficients is observed. Three-dimensional, transonic, flowfield computations over projectiles have been made using an implicit, approximately factored, partially flux-split algorithm. A composite grid scheme has been used to provide the increased grid resolution needed for accurate numerical simulation of three-dimensional transonic flows. Details of the asymmetrically located shock waves on the projectiles have been determined. Computed surface pressures have been compared with experimental data and are found to be in good agreement. The pitching moment coefficient, determined from the computed flowfields, shows the critical aerodynamic behavior observed in free flights. I. Introduction T HE flight of projectiles covers a wide range of speeds. The accurate prediction of projectile aerodynamics at these speeds is of significant importance in the early design stage of a projectile. The critical aerodynamic behavior occurs in the transonic speed regime, 0.9<M< 1.1 where the aerodynamic coefficients have been found to change by as much as 100%. Of particular interest is the determination of the pitching-moment coefficient since it is used to determine the static stability of the projectile. The critical behavior in this case is usually characterized by a rapid increase in the coefficient followed by a sharp drop. This rapid change in the pitchingmoment coefficient can be attributed in part to the complex
Experimental CW Chemical Laser Studies

Abstract : Experimental studies of The Aerospace Corporation's continuously operating diffusion-type HF chemical lasers are presented. Nonuniform flow profiles at the laser nozzle exit are deducted by the use of pitot and total-temperature probes. The presence of shock waves and the measured flow profiles were of particular interest in the explanation of laser performance under varied flow conditions. Low-diluent-ratio flows resulted in a deterioration of laser performance partly because of thermal blockage effects. Alternate nozzles were plugged in order to provide lateral jet expansion relief, which resulted in improved laser performance. Pressure scaling was investigated up to approximately 5 atm plenum pressure and 16-Torr cavity pressure. For fixed plenum conditions, an increase in cavity pressure resulted in a decrease in laser power and axial lasing length (due to oblique shocks and nozzle separation). For fixed cavity pressure, an increase in plenum pressure resulted in an increase in power and axial lasing length (due to a reduced boundary layer). The cavity pressure for peak power corresponded quite closely to the cavity pressure predicted for matched nozzle flow. (Author)
The first Cu- and amine-free Sonogashira-type cross-coupling in the C-6-alkynylation of protected 2'-deoxyadenosine

The Sonogashira cross-coupling reaction offers a convenient route to C(sp)–C(sp2) bond formation. Although the Sonogashira reaction has traditionally been carried out in the presence of Pd catalyst and a co-catalyst of Cu(I) salt, the use of Cu(I) salt is often not efficient because it leads to the formation of unwanted side-products. This has prompted interest in recent years in the development of Cu-free Sonogashira cross-coupling reaction conditions. In addition, the development of Cu-free Sonogashira cross-coupling conditions for the alkynylation of nucleoside derivatives remains largely unexplored. Herein, we demonstrate that Cu- and amine-free Sonogashira-type cross-coupling lead to successful alkynylation of aryl bromides and heteroaryl bromides. For the first time, we have extended this method for the alkynylation of protected 2′-deoxyadenosine at the C-6 position.
Level sets of signed Takagi functions

This paper examines level sets of functions of the form $$ f(x)=\sum_{n=0}^\infty \frac{r_n}{2^n}\phi(2^n x), $$ where $\phi(x)=\operatorname{dist}\, (x,\mathbb {Z})$ , the distance from x to the nearest integer, and r n =±1 for each n. Such functions are referred to as signed Takagi functions. The case when r n =1 for all n is the classical Takagi function, a well-known example of a continuous but nowhere differentiable function. For f of the above form, the maximum and minimum values of f are expressed in terms of the sequence {r n }. It is then shown that almost all level sets of f are finite (with respect to Lebesgue measure on the range of f), but the set of ordinates y with an uncountably large level set is residual in the range of f. The concept of a local level set of the Takagi function, due to Lagarias and Maddock, is extended to arbitrary signed Takagi functions. It is shown that the average number of local level sets contained in a level set of f is the reciprocal of the height of the graph of f, and consequently, this average lies between 3/2 and 2. These results generalize recent findings by Buczolich [8], Lagarias and Maddock [14], and Allaart [3].
Weyburn Field Seismic Monitoring Project

High-resolution, time-lapse (4-D), multicomponent (9-C) seismic data acquired by the Reservoir Characterization Project (RCP) of the Colorado School of Mines were used to monitor a miscible CO2 flood in a thin (30m) carbonate reservoir at a depth of 1450m in Weyburn field, Saskatchewan. Multicomponent time-lapse seismic images illustrate the influence of fracture zones on the flood. These fracture zones are very important to characterize and monitor in order to manage the flood successfully and to achieve the desired improved recovery efficiency.
A QCD calculation of the interaction of quarkonium with nuclei

Abstract The interaction of quarkonium with nuclei is studied in the m Q →∞ limit of QCD, where the binding energy is found to be exactly computable. The dominant contribution to the interaction is from two-gluon operators. The forward matrix elements of these two-gluon operators can be determined from the QCD scale anomaly, and from deep inelastic scattering. We apply our results to the υ and J ψ treating the Q Q interaction as purely coulombic. We find the υ binds in nuclear matter with a binding energy of a few MeV, while for the J ψ binding is of order 10 MeV. For the J ψ in particular we expect confinement effects to produce large corrections to this result.
MULTISCALE ANALYSIS OF ELECTRORHEOLOGICAL FLUIDS

We construct a microscale model for a rigid particle suspension in a viscous fluid that includes Maxwell electrostatic forces. Via homogenization techniques we characterize the properties the material exhibits at the macroscale. The change in the effective constitutive equations is due to the highly oscillating electrostatic forces. The material properties are determined by both hydrodynamic and electrostatic particle interactions.
A New Finite-Element Based Suspension Model Including Displacement Limiters for Load/Unload Simulations

A new beam suspension model for load/unload simulations of magnetic hard disk drive sliders is presented. The model is applicable to the load/unload process as well as to the dynamic flying behavior of the slider on the disk. Suspension and gimbal are modeled with C 1 continuous beam elements. The roll degree of freedom of the slider is decoupled from spacing and pitch. The numerical implementation of the model is described. Loading and unloading of a typical subambient pressure type slider is presented.
Imaging techniques for diagnosis of infective endocarditis.

With the ability to structurally characterize cardiac manifestations, echocardiography is used for the diagnosis and management of infective endocarditis. In establishing the diagnosis according to the Duke criteria, the findings of endocardial involvement (vegetation, abscess, prosthetic valve dehiscence) or new valvular regurgitation represent "major" diagnostic criteria. Echocardiography cannot reliably differentiate noninfective from infective lesions; however, proper diagnosis lies in correlating echocardiography with clinical findings. The more invasive transesophageal approach provides substantially greater image resolution; this approach should be considered first in the evaluation of patients with higher prior probabilities of endocarditis and those with potential endocardial complications.
Well-Balanced Central Schemes on Overlapping Cells with Constant Subtraction Techniques for the Saint-Venant Shallow Water System

We develop well-balanced finite-volume central schemes on overlapping cells for the Saint-Venant shallow water system and its variants. The main challenge in deriving the schemes is related to the fact that the Saint-Venant system contains a geometric source term due to nonflat bottom topography and therefore a delicate balance between the flux gradients and source terms has to be preserved. We propose a constant subtraction technique, which helps one to ensure a well-balanced property of the schemes, while maintaining arbitrary high-order of accuracy. Hierarchical reconstruction limiting procedure is applied to eliminate spurious oscillations without using characteristic decomposition. Extensive one- and two-dimensional numerical simulations are conducted to verify the well-balanced property, high-order of accuracy, and non-oscillatory high-resolution for both smooth and nonsmooth solutions.
GENERALIZED BARRETT–CRANE VERTICES AND INVARIANTS OF EMBEDDED GRAPHS

In [1] Barrett and Crane introduce a modification of the generalized CraneYetter state-sum (cf. [2]) based on the category of representations of Spin(4) ∼= SU(2)×SU(2), which provides a four-dimensional analogue of Regge and Ponzano’s [9] spin-network formulation of three-dimensional gravity. The key to the modification of the Crane-Yetter state-sum is the use of a different intertwiner between the “inbound” and “outbound” tensor products of objects assigned to faces of the tetrahedron, thereby imposing a “quantum analogue” of the condition that the sum of the simple bivectors represented by two faces with a common edge is itself simple. The purposes of this paper are
Dynamical Threshold Behavior of A Sliding Charge Density Wave

Abstract It is argued that the existence of a dynamical threshold field [i.e. the value of the electric field such that when the applied field is reduced to this value the charge density wave (CDW) stops sliding] requires that the sliding of the CDW at low center of mass velocity occurs as local sudden jumping motion reminiscent of “stick-slip” friction. Using this model, it is argued in the weak impurity limit that the static threshold field is greater than the dynamic threshold field.
Polymer geometry at Planck scale and quantum Einstein equations

It is well known that quantum general relativity is perturbatively non-renormalizable. Particletheorists often take this to be a sufficient reason to abandon general relativity and seek an alternative which has a better ultraviolet behavior in perturbation theory. However, one is by no means forced to this route. For, there do exist a number of field theories which are perturbatively non-renormalizable but are exactly soluble. An outstanding example is the Gross-Neveau model in 3 dimensions, (GN)3, which was recently shown to be exactly soluble rigorously [1]. Furthermore, the model does not exhibit any mathematical pathologies. For example, it was at first conjectured that the Wightman functions of a non-renormalizable theory would have a worse mathematical behavior. The solution to (GN)3 showed that this is not the case; as in familiar renormalizable theories, they are tempered distributions. Thus, one can argue that, from a structural viewpoint, perturbative renormalizability is a luxury even in Minkowskian quantum field theories. Of course, it serves as a powerful guiding principle for selecting physically interesting theories since it ensures that the predictions of the theory at a certain length scale are independent of the potential complications at much smaller scales. But it is not a consistency check on the mathematical viability of a theory. Furthermore, in quantum gravity, one is interested precisely in the physics of the Planck scale; the short-distance complications are now the issues of primary interest. Therefore, it seems inappropriate to elevate perturbative renormalizability to a viability criterion.
Fault modeling of physical failures in CMOS VLSI circuits

The analog complex physical fault of a gate-to-drain short in VLSI CMOS circuits is studied. A relationship between the inverse voltage of an inverter and the faulty voltage output is obtained and is then used to study the propagation of the faulty signal through successive gates. General graphical rules are developed which describe techniques for obtaining the operating point of the circuit through table look-up procedures. The technique is simple and can easily be added to known fault-simulation algorithms. >
Groups Acting on CAT (0) Square Complexes

We study groups acting on CAT(0) square complexes. In particular we show if Y is a nonpositively curved (in the sense of Alexandrov) finite square complex and the vertex links of Ycontain no simple loop consisting of five edges, then any subgroup of π 1Y either is virtually free Abelian or contains a free group of rank two. In addition we discuss when a group generated by two hyperbolic isometries contains a free group of rank two and when two points in the ideal boundary of a CAT(0) 2-complex at Tits distance π apart are the endpoints of a geodesic in the 2-complex.
Iterated Point–Line Configurations Grow Doubly-Exponentially

Begin with a set of four points in the real plane in general position. Add to this collection the intersection of all lines through pairs of these points. Iterate. Ismailescu and Radoicic (Comput. Geom. 27:257–267, 2004) showed that the limiting set is dense in the plane. We give doubly exponential upper and lower bounds on the number of points at each stage. The proof employs a variant of the Szemeredi–Trotter Theorem and an analysis of the “minimum degree” of the growing configuration.
Is PIN priced risk

Abstract Several recent papers assume that private information (PIN), proposed by Easley et al. [2002. Is information risk a determinant of asset returns? Journal of Finance 57, 2185–2221; 2004. Factoring information into returns. Working Paper, Cornell University], is a determinant of stock returns. We replicate Easley et al. (2002) and show that while PIN does predict future returns in the sample they analyze, the effect is not robust to alternative specifications and time periods. There is no evidence that PIN factor loadings predict returns or that PIN factor returns reflect future GDP growth. PIN exhibits no association with implied cost of capital derived from analysts’ earnings forecasts. Overall, our findings cast doubt on whether PIN reflects information risk systematically priced by investors.
The spacetime geometry of a null electromagnetic field

We give a set of local geometric conditions on a spacetime metric which are necessary and sufficient for it to be a null electrovacuum, that is, the metric is partofasolutiontotheEinstein‐Maxwellequationswithanullelectromagnetic field. These conditions are restrictions on a null congruence canonically constructed from the spacetime metric, and can involve up to five derivatives of the metric. The null electrovacuum conditions are counterparts of the Rainich conditions, which geometrically characterize non-null electrovacua. Given a spacetime satisfying the conditions for a null electrovacuum, a straightforward procedure builds the null electromagnetic field from the metric. Null electrovacuum geometry is illustrated using some pure radiation spacetimes taken from the literature.
Wake Sensing for Aircraft Formation Flight

It is well established that flying aircraft in formation can lead to improved aerodynamic efficiency. However, successfully doing so is predicated on having knowledge of the lead aircraft’s wake position. Here, a wake-sensing strategy for estimating the wake position and strength in a two-aircraft formation is explored in a simplified proof-of-concept setting. The wake estimator synthesizes wing-distributed pressure measurements, taken on the trailing aircraft, by making use of an augmented lifting-line model in conjunction with both Kalman-type and particle filters. Simple aerodynamic models are introduced in constructing the filter to enable fundamental wake-sensing challenges to be identified and reconciled. The various estimation algorithms are tested in a vortex lattice simulation environment, thus allowing the effects of modeling error to be analyzed. It is found that biases in the position estimates no longer arise if a particle filter is used in place of the Kalman-type filters. Filter divergence ...
Experimental study of the parallel velocity shear instability

Abstract The parallel velocity shear instability (PVSI) is experimentally investigated in a double-ended Q machine in which the shear in the ion flow is produced by suitable shaping of the axial magnetic field. Instability fluctuation levels approaching nearly 100% are often observed.
A measurement of the electromagnetic luminosity of a kerr black hole

Some active galactic nuclei, microquasars, and gamma-ray bursts may be powered by the electromagnetic braking of a rapidly rotating black hole. We investigate this possibility via axisymmetric numerical simulations of a black hole surrounded by a magnetized plasma. The plasma is described by the equations of general relativistic magnetohydrodynamics, and the effects of radiation are neglected. The evolution is followed for 2000GM/c3, and the computational domain extends from inside the event horizon to typically 40GM/c2. We compare our results to two analytic steady state models, including the force-free magnetosphere of Blandford & Znajek. Along the way we present a self-contained rederivation of the Blandford-Znajek model in Kerr-Schild (horizon penetrating) coordinates. We find that (1) low-density polar regions of the numerical models agree well with the Blandford-Znajek model, (2) many of our models have an outward Poynting flux on the horizon in the Kerr-Schild frame, (3) none of our models have a net outward energy flux on the horizon, and (4) one of our models, in which the initial disk has net magnetic flux, shows a net outward angular momentum flux on the horizon. We conclude with a discussion of the limitations of our model, astrophysical implications, and problems to be addressed by future numerical experiments.
Meson transition form factors from a QCD model field theory

Abstract We discuss form factors and coupling constants for the γ ∗ π 0 γ , ϱππ and γπϱ interactions generated by a model field theory that produces finite size q q meson modes. The approach implements dressing of the vertices and propagators consistent with dynamical chiral symmetry breaking, gauge invariance, quark confinement and perturbative QCD.
Scale Effects of Elastic-Plastic Behavior of Microscopic Asperity Contacts

Scale effects of elastic-plastic asperity microcontact behavior are studied theoretically using a new simulation method developed by the authors. Contact plastic deformation is described in terms of discrete dislocations, which allows the model to be made scale-sensitive. The present work deals with two-dimensional asperity microcontacts. It is found that when asperity size decreases and becomes comparable to the characteristic microstructural length, contact plastic deformation becomes increasingly difficult, and finally impossible. The effect of a simultaneous decrease in the asperity size and the microstructural length is also studied.
Efficient use of route requests for loop-free on-demand routing in ad hoc networks

On-demand routing protocols flood a route request (RREQ) identified by a unique source-sequenced label (SSL) to build directed acyclic graphs (DAG) consisting of possible paths to destinations, and use reverse paths along such DAGs to send route replies from the destinations. We present the first framework that uses only the SSL of the RREQ to establish loop-free paths without requiring additional mechanisms or information, e.g., per destination-sequence numbers or source routing. We present the Labeled Successor Routing (LSR) protocol, which stores the SSL of the RREQ as a route request label (RRL) at the nodes that participated in the creation of the RREQ DAG. The RRLs allow the source of the RREQ to identify neighbors as loop-free successors to the destination, which reduces network-wide RREQ flooding. Simulations results for scenarios consisting of networks of 50 and 100 mobile nodes show that LSR performs comparably or better than the Dynamic Source Routing (DSR) protocol, the Ad hoc On-demand Distance Vector (AODV) routing protocol, and the Optimized Link State Routing (OLSR) protocol.
Charged dilatonic AdS black branes in arbitrary dimensions

We study electromagnetically charged dilatonic black brane solutions in arbitrary dimensions with flat transverse spaces, that are asymptotically AdS. This class of solutions includes spacetimes which possess a bulk region where the metric is approximately invariant under Lifshitz scalings. Given fixed asymptotic boundary conditions, we analyze how the behavior of the bulk up to the horizon varies with the charges and derive the extremality conditions for these spacetimes.
Utility optimal scheduling in processing networks

We consider the problem of utility optimal scheduling in general processing networks with random arrivals and network conditions. These are generalizations of traditional data networks where commodities in one or more queues can be combined to produce new commodities that are delivered to other parts of the network, and can be used to model problems such as in-network data fusion, stream processing, MapReduce scheduling, and grid computing. Scheduling actions are complicated by the underflow problem that arises when some queues with required components go empty. In this paper, we develop a novel methodology for constructing and analyzing online algorithms for such processing networks. Specifically, we develop the Perturbed Max-Weight algorithm (PMW) to achieve optimal utility. The idea of PMW is to perturb the weights used by the usual Max-Weight algorithm to ''push'' queue levels toward non-zero values (avoiding underflows). We then show, using a novel combination of Lyapunov drift analysis and duality theory, that when the perturbations are carefully chosen, PMW is able to achieve a utility that is within O(1/V) of the optimal value for any V>=1, while ensuring an average network backlog of O(V). The methodology developed here is very general and can also be applied to other problems that involve such underflow constraints.
X-ray studies of the structure of thermotropic copolyesters

Abstract This paper describes x-ray analysis of the structure of a group of wholly aromatic thermotropic liquid crystalline copolyesters, focusing on two systems: condensation copolymers of 4-hydroxy-benzoic acid (HBA) and 2-hydroxy–6-naphthoic acid; and of HBA, 2,6-dihydroxy-naphthalene, and terephthalic acid. The fiber diagrams of these copolymers contain a series of aperiodic meridional maxima that shift in position with the monomer ratio. We have shown that these characteristics are predicted by a structure consisting of an array of chains of completely random monomer sequence. The positions of the maxima are predicted by a simple model in which the monomers are represented by points, separated from their neighbors by the appropriate monomer lengths. Use of atomic models for the monomers leads to prediction of both the positions and the intensities of the maxima. Calculations for nonrandom sequence distribution show that all but minimal blockiness can be ruled out. From the breath of the meridional ma...
Phase shift in experimental trajectory scaling functions

Abstract For one-dimensional maps the trajectory scaling function is invariant under coordinate transformations and can be used to compute any ergodic average. It is the most stringent test between theory and experiment, but so far it has proven difficult to extract from experimental data. It is shown that the main difficulty is a dephasing of the experimental orbit which can be corrected by reconstructing the dynamics from several time series. From the reconstructed dynamics the scaling function can be accurately extracted.
Exact solution of the nuclear pairing problem

Abstract In many applications to finite Fermi-systems, the pairing problem has to be treated exactly. We suggest a numerical method of exact solution based on SU(2) quasispin algebras and demonstrate its simplicity and practicality. We show that the treatment of binding energies with the use of the exact pairing and uncorrelated monopole contribution of other residual interactions can serve as an effective alternative to the full shell-model diagonalization in spherical nuclei.
Search for Higgs and new phenomena at colliders

The present status of searches for the Higgs boson(s) and new phenomena is reviewed. The focus is on analyses and results from the current runs of the HERA and Tevatron experiments. The LEP experiments have released their final combined MSSM Higgs results for this conference. Also included are results from sensitivity studies of the LHC experiments and lepton flavour violating searches from the B factories, KEKB and PEP-II.
Preparation of the major urinary metabolite of (−)-prostaglandin E2

Abstract The best way to measure whole body production of the locally acting hormone prostaglandin E2 (PGE2) is to assess the accumulation of the major urinary metabolite, PGE2UM. A practical preparation of this delicate diacid is described. This synthetic PGE2UM will enable production of the antibodies that will be used to quantify this key metabolite.