cssi/SciSciGPT-SciSciNet huggingface dataset:
Electronic inhomogeneity at magnetic domain walls in strongly correlated systems

We show that nano-scale variations of the order parameter in strongly correlated systems can induce local spatial regions such as domain walls that exhibit electronic properties representative of a different, but nearby, part of the phase diagram. This is done by means of a Landau-Ginzburg analysis of a metallic ferromagnetic system near an antiferromagnetic phase boundary. The strong spin gradients at a wall between domains of different spin orientation drive the formation of a new type of domain wall, where the central core is an insulating antiferromagnet, and connects two metallic ferromagnetic domains. We calculate the charge transport properties of this wall, and find that its resistance is large enough to account for recent experimental results in colossal magnetoresistance materials. The technological implications of this finding for switchable magnetic media are discussed.
Correction of massive vaginal prolapse in an older population : a four-year experience at a rural tertiary care center

Objective: To ascertain the success of complex reconstructive vaginal surgery in older women. Design: Retrospective review of hospital and outpatient records. Setting: Rural tertiary care referral center, Pennsylvania State University Hospital, Hershey, Pennsylvania Patients: Twenty-four patients referred for massive eversion of the vagina and/or complete procidentia. Measurements: Symptoms and anatomic correction of patients' complaints. Results: After surgery, 83 percent were asymptomatic without pelvic relaxation, 4 percent were asymptomatic with pelvic relaxation, 4 percent were symptomatic without pelvic relaxation, and 9 percent were symptomatic with relaxation. Conclusions: Older women can undergo major vaginal reconstructive surgery with relief of symptoms and restoration of vaginal depth and axis.
Fabrication-Adaptive Optimization with an Application to Photonic Crystal Design

It is often the case that the computed optimal solution of an optimization problem cannot be implemented directly, irrespective of data accuracy, because of either i technological limitations such as physical tolerances of machines or processes, ii the deliberate simplification of a model to keep it tractable by ignoring certain types of constraints that pose computational difficulties, and/or iii human factors getting people to “do” the optimal solution. Motivated by this observation, we present a modeling paradigm called “fabrication-adaptive optimization” for treating issues of implementation/fabrication. We develop computationally focused theory and algorithms, and we present computational results for incorporating considerations of implementation/fabrication into constrained optimization problems that arise in photonic crystal design. The fabrication-adaptive optimization framework stems from the robust regularization of a function. When the feasible region is not a normed space as typically encountered in application settings, the fabrication-adaptive optimization framework typically yields a nonconvex optimization problem. In the special case where the feasible region is a finite-dimensional normed space, we show that fabrication-adaptive optimization can be recast as an instance of modern robust optimization. We study a variety of problems with special structures on functions, feasible regions, and norms for which computation is tractable and develop an algorithmic scheme for solving these problems in spite of the challenges of nonconvexity. We apply our methodology to compute fabrication-adaptive designs of two-dimensional photonic crystals with a variety of prescribed features.
The first solvent-free method for the reduction of esters

Utilizing the novel technique of high-speed ball milling, we herein report the first solvent-free reduction of esters.
Feedback regulation of the alpha electroencephalogram activity through control of the internal and external parameters

Experiments with feedback stimulation triggered from the subject’s electroencephalogram result in changing the sequential time series of intervals of occipital alpha and intervals of little or no alpha EEG activity. The rate of recurrence of alpha and no-alpha EEG can be changed by regulating the external feedback stimuli or by asking the subject to change his internal state. Four different paradigms were investigated and the results interpreted in terms of the hypothesis that oculomotor functions regulate the occurrence and nonoccurrence of alpha.
Platforms and Real Options in Industrial Organization

We need a robust theory to analyse the dynamics of new industrial organizations that are being created by the explosion of information technology. This paper sets out a new theoretical perspective and suggests a new empirical framework towards formulating such a theory. The new conceptual tools of analysis presented here include the “platform” as a key element of new market structures, “real options” analysis to deal with genuine uncertainty, and an understanding of a new form of competition that takes place among different platforms. JEL Classification Numbers: L10, L12, L15, D81.
An economic analysis of drawing lines in the sea

It is shown that low dispute costs relative to expected resource rents from oceanic resources favor drawn out disputes over maritime boundaries; asymmetric dispute costs favor agreement on boundaries wanted by the low dispute cost state party; and high symmetric dispute costs favor formation of joint development zones (JDZs). The fact that most maritime boundaries have not yet been drawn suggests that state parties think that resource rents that can be drawn from the oceans are high relative to dispute costs. Moreover, the recent mini-trend towards JDZs in East Asia suggests that state parties in the area have recently reassessed dispute costs as being higher than previously believed.
Selective Nanocrystal Synthesis and Calculated Electronic Structure of All Four Phases of Copper–Antimony–Sulfide

A wide variety of copper-based semiconducting chalcogenides have been investigated in recent years to address the need for sustainable solar cell materials. An attractive class of materials consisting of nontoxic and earth abundant elements is the copper–antimony–sulfides. The copper–antimony–sulfide system consists of four major phases, namely, CuSbS2 (Chalcostibite), Cu12Sb4S13 (Tetrahedrite), Cu3SbS3 (Skinnerite), and Cu3SbS4 (Fematinite). All four phases are p-type semiconductors having energy band gaps between 0.5 and 2 eV, with reported large absorption coefficient values over 105 cm–1. We have for the first time developed facile colloidal hot-injection methods for the phase-pure synthesis of nanocrystals of all four phases. Cu12Sb4S13 and Cu3SbS3 are found to have direct band gaps (1.6 and 1.4 eV, respectively), while the other two phases display indirect band gaps (1.1 and 1.2 eV for CuSbS2 and Cu3SbS4, respectively). The synthesis methods yield nanocrystals with distinct morphology for the differ...
Novel Mixed-Valent (V/VI) Triple Perovskite Ruthenates: Observation of a Complex Low-Temperature Structural and Magnetic Transition

Two new mixed-valent triple perovskites, Ba3MRu2O9 (M = Li, Na), were grown from reactive hydroxide fluxes. They crystallize in the hexagonal space group P63/mmc, where Ru(V) and Ru(VI) are disordered on only one crystallographic site. Upon cooling, single crystals of Ba3NaRu2O9 undergo a complex symmetry-breaking structural transition at ca. 225 K from room-temperature hexagonal symmetry to a low-temperature orthorhombic symmetry, space group Cmcm. Accompanying this structural transition is a rather abrupt decrease in the magnetic susceptibility at 210 K followed by a steady decrease in the susceptibility with decreasing temperature. Interestingly, the lithium analogue does not display any structural transition down to 100 K. The structural transition in Ba3NaRu2O9 generates three crystallographically unique Ru sites in the low-temperature structure as compared to only one distinct site in the room-temperature structure. On the basis of an analysis of the Ru−Ru distances in the face-sharing bi-octahedra,...
Progress in photon scanning tunneling microscopy (PSTM)

Abstract Tunneling of either electrons or photons from a sample to a probe tip yields an exponential signal that permits subwavelenght tangential resolution and even better resolution of the tip-to-sample distance. PSTM provides images of both insulators and conductors that are either thin or not too strongly absorbing at the wavelength used. STM provides better spatial resolution but poorer spectroscopic resolution, so there are complementary aspects for the two instruments. Our recent progress with the PSTM includes adding a zoom capability, detection of surface-enhanced Raman signals, imaging of photolithographically prepared arrays of isolated silver particles, and studies of tunneling effects on films of photoresist.
Second primary malignancies associated with renal cell carcinoma: influence of histologic type.

Abstract Objectives. This study was performed to determine which histologic types of renal cell carcinoma have an association with a second primary malignancy. Methods. Seven hundred sixty-three patients underwent an operation for renal cell carcinoma between July 1989 and January 1999. The incidence of antecedent, synchronous, or subsequent second malignancies was determined. Statistical tests based on the Poisson model were used to compare the observed number of subsequent malignancies developing after a diagnosis of renal cell carcinoma with the expected number calculated using the 1973 to 1994 U.S. Surveillance, Epidemiology, and End Results age, race, gender, and calendar-year specific incidence rates. Results. Second primary malignancies were present in 209 of 763 (27.4%) patients, with prostate, breast, colon, and bladder cancer and non-Hodgkin's lymphoma being the five most common second malignancies. The other malignancies were antecedent in 118 cases (44.5%), synchronous in 104 cases (39.2%), and subsequent in 43 cases (16.2%). Patients with papillary renal cell carcinoma were at increased risk of developing bladder cancer (standardized incidence ratio [SIR] 6.5, P = 0.038). Men with papillary renal cell carcinoma were also at increased risk of developing prostate cancer (SIR 2.8, P = 0.035). Conclusions. There is an increased risk of subsequent bladder and prostate cancer in patients with papillary renal cell carcinoma.
Maskless Patterning and Structuring on Ultra-Hard Film Materials

Ultra-hard film materials such as chemical vapor deposited (CVD) diamond are uniquely qualified for applications where superior tribological and electronic properties are required. Patterning of the film materials is essential to produce functional micro devices. Conventional lithography-based chemical etching is difficult or impossible on the ultra-hard diamond film materials, which have a high chemical resistance. Investigations on maskless patterning of the CVD diamond film are presented. Focused excimer laser pulses are used for dry etching on the film materials, and a micro computer numerical control (micro-CNC) stage is used for patterned translation of a target. The laser ablation of CVD diamond is observed to set up relationships among the processing parameters, such as the gas processing environments, the laser energy fluence and the number of laser pulses. The extent of the ablation-induced plasma is observed by time integrated image capturing. A cell-patterned structure, fabricated by the innovative maskless process, is presented for discussion.
The Arizona virtual patient: using question-answering technology to enhance dialogue processing

The Arizona Virtual Patient (AVP) is a dialogue-based patient simulator for training pharmacy students. The AVP uses state-of-the-art question-answering techniques, including a taxonomy of expected answer types. After the user enters a question, a database of patient profiles is queried and an appropriate answer in the form of a video is displayed. The patient database can be augmented by non-programmers. It is argued that the AVP is an effective tool for instructing pharmacy students in pharmacist-patient interaction.
Strings on pp-waves and massive two-dimensional field theories

Abstract We find a general class of pp-wave solutions of type IIB string theory such that the light cone gauge worldsheet Lagrangian is that of an interacting massive field theory. When the light cone Lagrangian has (2,2) supersymmetry we can find backgrounds that lead to arbitrary superpotentials on the worldsheet. We consider situations with both flat and curved transverse spaces. We describe in some detail the background giving rise to the N=2 sine Gordon theory on the worldsheet. Massive mirror symmetry relates it to the deformed CP1 model (or sausage model) which seems to elude a purely supergravity target space interpretation. To cite this article: J. Maldacena, L. Maoz, C. R. Physique 4 (2003).
An Experimental Study of Bearing and Thread Friction in Fasteners

An experimental procedure is proposed for studying the underhead and thread friction in fasteners. The effective bearing friction radius, the underhead friction coefficient, and the thread friction coefficient are experimentally determined for fasteners with standard hexagonal heads and for flanged head fasteners. Hence, greater accuracy has been achieved in determining the value of the torque components that are consumed in overcoming friction in threaded fasteners. This would lead to a more reliable torque-tension correlation and would enhance the safety and quality of bolted assemblies. A design of experiment procedure is presented in order to investigate the effect of fastener material class, the thread pitch, and the fastener size on thread friction coefficient. For the underhead bearing friction, an experimental model is presented in order to determine the effect of the radii ratio of the contact area on the bearing friction radius.
Generation of Magnetic Fields by the Stationary Accretion Shock Instability

We begin an exploration of the capacity of the stationary accretion shock instability (SASI) to generate magnetic fields by adding a weak, stationary, and radial (but bipolar) magnetic field, and in some cases rotation, to an initially spherically symmetric fluid configuration that models a stalled shock in the post-bounce supernova environment. In axisymmetric simulations, we find that cycles of latitudinal flows into and radial flows out of the polar regions amplify the field parallel to the symmetry axis, typically increasing the total magnetic energy by about 2 orders of magnitude. Non-axisymmetric calculations result in fundamentally different flows and a larger magnetic energy increase: shearing associated with the SASI spiral mode contributes to a widespread and turbulent field amplification mechanism, boosting the magnetic energy by almost 4 orders of magnitude (a result which remains very sensitive to the spatial resolution of the numerical simulations). While the SASI may contribute to neutron star magnetization, these simulations do not show qualitatively new features in the global evolution of the shock as a result of SASI-induced magnetic field amplification.
Acute esophageal necrosis: a case series of five patients presenting with "Black esophagus".

Acute esophageal necrosis (AEN), also known as “Black esophagus”, is a rare condition that typically presents as upper gastrointestinal hemorrhage. A retrospective chart analysis was conducted at two tertiary care hospitals over a three-year period (2005–2007) using a computerized inpatient database. Out of 9,179 upper endoscopies performed, five patients (0.05% prevalence) were found to have black esophagus. Their mean age was 44 years and the most common presentation was upper gastrointestinal bleeding. All five patients had comorbid conditions, most commonly coronary artery disease, diabetes mellitus, and renal insufficiency. Two patients died, but the cause of death was not related to AEN in either. In conclusion, AEN is usually seen in critically ill elderly patients with multiple comorbid conditions, particularly vascular disease, diabetes mellitus and azotemia.
Structured interference-mitigation in two-hop networks

We consider two-hop S-R-D Gaussian networks with a source (S), a relay (R) and a destination (D), some of which experience additive interference. This additive interference, which renders the channels state-dependent, is either a) experienced at the destination D and known non-causally at the source S, or b) experienced at the relay R and known at the destination D. In both cases, one would hope to exploit this knowledge of the channel state at some of the nodes to obtain “clean” or interference-free channels, just as Costa's dirty-paper coding does for one-hop channels with state non-causally known to the transmitter. We demonstrate a scheme which achieves to within ½ bit of a “clean” channel. This novel scheme is based on nested-lattice code and a Decode-and-Forward (DF) relay. Intuitively, this strategy uses the structure provided by nested lattice codes to cancel the “integer” (or lattice quantized) part of the interference and treats the “residual” (or quantization noise) as noise.
The Redox-A3 Reaction

This highlight details the recent emergence of a new type of A3 reaction (three-component condensation of an amine, an aldehyde and an alkyne). In contrast to the classic A3 coupling process, the redox-A3 reaction incorporates an iminium isomerization step and leads to amine α-alkynylation. The overall transformation is redox-neutral by virtue of a combined reductive N-alkylation/oxidative C–H bond functionalization.
AN EFFICIENT SYNTHESIS OF 2-ARYL AND 2-ALKENYL-3-ALKOXY-CYCLOHEXENONES BY A MODIFIED STILLE REACTION

Abstract A general direct procedure for the synthesis of 2-aryl and 2-alkenyl-3-alkoxy-cyclohexenones using a modified Stille coupling is described.
Electromechanical computing at 500°C with silicon carbide

Logic circuits capable of operating at high temperatures can alleviate expensive heat-sinking and thermal-management requirements of modern electronics and are enabling for advanced propulsion systems. Replacing existing complementary metal-oxide semiconductor field-effect transistors with silicon carbide (SiC) nanoelectromechanical system (NEMS) switches is a promising approach for low-power, high-performance logic operation at temperatures higher than 300°C, beyond the capability of conventional silicon technology. These switches are capable of achieving virtually zero off-state current, microwave operating frequencies, radiation hardness, and nanoscale dimensions. Here, we report a microfabricated electromechanical inverter with SiC complementary NEMS switches capable of operating at 500°C with ultralow leakage current.
The varieties of quasigroups of Bol–Moufang type: An equational reasoning approach

Abstract A quasigroup identity is of Bol–Moufang type if two of its three variables occur once on each side, the third variable occurs twice on each side, the order in which the variables appear on both sides is the same, and the only binary operation used is the multiplication, viz. ( ( x y ) x ) z = x ( y ( x z ) ) . Many well-known varieties of quasigroups are of Bol–Moufang type. We show that there are exactly 26 such varieties, determine all inclusions between them, and provide all necessary counterexamples. We also determine which of these varieties consist of loops or one-sided loops, and fully describe the varieties of commutative quasigroups of Bol–Moufang type. Some of the proofs are computer-generated.
Filtering Horizon-Sensor Measurements for Orbital Navigation

Optimal filtering theory is applied to the problem of processing horizon-sensor data so as to compensate for the unusual statistical properties that characterize the associated errors. An examination of the statistical characteristics of the variations in apparent-horizon altitude, together with the geometry of the measurement process, reveals correlation functions of unusual form corresponding to the various error components present in the horizon-sensor measurements. Filtering techniques are then derived by the application of optimal filtering theory to approximate statistical models of varying degrees of complexity. An essential operation is the fitting of simple correlation-function models to the true correlation functions exhibited by the random processes in question. It follows that proper choice of the measurement schedule can greatly enhance the effectiveness of the filter employed. The random functions involved are basically space-dependent rather than time-dependent; two methods are therefore given for the generation of a correlated random process on the surface of a sphere, for use in Monte Carlo simulations of the variations of horizon altitude. Numerical results are presented to demonstrate the effectiveness of the techniques developed.
A note on initial conditions and liberalization during transition

Abstract Literature explaining variations in economic performance among transition economies places a high level of importance on the role of policy. Policy differences are measured via a liberalization index used to explain differences in performance. We find that this index may be endogenous to one performance measure, e.g., output decline, and may, therefore, overstate the role of policy. This paper performs an instrumental variables (IV) estimate of the relationship between liberalization and performance that also allows us to generate a relative index of reform progress. The relative index challenges some commonly held preconceptions about which transition economies are rapid reformers and which are slow reformers. J. Comp. Econom., December 1998, 26(4), pp. 718–734. Macalester College, 1600 Grand Avenue, St. Paul, Minnesota 55105.
Local Smoothing for Scattering Manifolds with Hyperbolic Trapped Sets

We prove a resolvent estimate for the Laplace-Beltrami operator on a scattering manifold with a hyperbolic trapped set, and as a corollary deduce local smoothing. We use a result of Nonnenmacher-Zworski to provide an estimate near the trapped region, a result of Burq and Cardoso-Vodev to provide an estimate near infinity, and the microlocal calculus on scattering manifolds to combine the two.
Structural and physical properties of layered oxy-arsenides LnRuAsO (Ln=La, Nd, Sm, Gd)

Polycrystalline samples of LaRuAsO, NdRuAsO, SmRuAsO, and GdRuAsO have been synthesized and studied using powder x-ray diffraction, electrical transport, magnetization, and heat capacity measurements. Variations in structural properties across the series reveal a trend toward more ideal tetrahedral coordination around Ru as the size of the rare earth element is reduced. The lattice parameters of these Ru compounds show a more anisotropic response to variation in Ln than their Fe analogs, and significant anisotropy in thermal expansion is also observed. Transport measurements show metallic behavior, and carrier concentrations near 10{sup 21}-10{sup 22} electrons per cm{sup 3} are inferred from simple analysis of Hall effect measurements. Anomalies in resistivity, magnetization, and heat capacity indicate antiferromagnetic ordering of rare earth moments at 5 K for GdRuAsO, 4.5 K for SmRuAsO, and <2K for NdRuAsO. Magnetization measurements on LaRuAsO show no evidence of a magnetic moment on Ru. Observed behaviors are compared to those reported for similar Fe and Ru compounds. - Graphical abstract: Analysis of crystal structure, electrical transport, magnetic susceptibility, and heat capacity of LaRuAsO, NdRuAsO, SmRuAsO, and GdRuAsO. Highlights: Black-Right-Pointing-Pointer Experimental investigation of LaRuAsO, NdRuAsO, SmRuAsO, and GdRuAsO. Black-Right-Pointing-Pointer Anisotropic lattice response to changing Ln radius and temperature. Black-Right-Pointing-Pointer Rumore » coordination becomes more ideal as Ln radius is reduced. Black-Right-Pointing-Pointer Transport measurements reveal metallic conduction dominated by electrons. Black-Right-Pointing-Pointer Magnetic measurements indicate antiferromagnetic ordering Nd, Sm, and Gd moments.« less
Weighted Bergman Spaces: Shift-Invariant Subspaces and Input/State/Output Linear Systems

It is well known that subspaces of the Hardy space over the unit disk which are invariant under the backward shift occur as the image of an observability operator associated with a discrete-time linear system with stable state-dynamics, as well as the functional-model space for a Hilbert space contraction operator, while forward shift-invariant subspaces have a representation in terms of an inner function. We discuss several variants of these statements in the context of weighted Bergman spaces on the unit disk.
The political economy of energy poverty: A review of key challenges

This review specifically investigates the concepts of energy poverty and energy ladders. It provides the most current available data on energy poverty, electrification, and dependency on biomass fuels for cooking. It elaborates on the relationship between energy access and millennium development goals, especially the connection between modern energy services and development, public health, gender empowerment, and the degradation of the natural environment. It notes that energy poverty has serious and growing public health concerns related to indoor air pollution, physical injury during fuelwood collection, and lack of refrigeration and medical care in areas that lack electricity. It argues that energy poverty affects both the gender roles within society and the educational opportunities available to children and adults. It documents that the environmental impacts of energy poverty encompass deforestation and changes in land use, as well as the emission of greenhouse gases. The final section of the review underscores the structural elements of the global energy system that entrench and sustain energy poverty.
Synthesis of silicon-functionalized dimethylsilyl enol ethers from ketones

Abstract Symmetrical dimethylsilyl bis-enol ethers are obtained in good yield by reaction of ketones with dichlorodimethylsilane in the presence of triethylamine and sodium iodide. Reaction of ketones with N, N - diethylaminodimethylchlorosilane in the presence of triethylamine and sodium iodide followed by subsequent conversions provides a useful synthesis of silicon-functionalized dimethylsilyl enol ethers including unsymmetrical dimethylsilyl bis-enol ethers
Ordering Structure and Dielectric Properties of Undoped and La/Na-Doped Pb(Mg1/3Nb2/3)O3

Transmission electron microscopy was used to study the ordered domain structures in undoped and La/Na-doped Pb(Mg1/3Nb2/3)O3 (PMN), where the compositions of the doped samples were specifically chosen so as to elucidate the ordering mechanism. The results showed that the Mg2+ ions and Nb5+ ions are short-range ordered on the B-site sublattice in undoped PMN, with a domain size of 2 to 5 nm. This short-range ordering gives rise to B-site composition fluctuations occurring on a nanometer scale, and it is this compositional inhomogeneity which is believed to be responsible for the diffuse phase transition behavior. Donor doping with La2O3 can compensate for the local charge imbalance resulting from the short-range order and thus enhances the degree of ordering. Acceptor doping with Na2O, however, increases the charge effect, and hence ordering is suppressed. The effect of Na doping and La doping on the dielectric properties of PMN is also discussed.
Going off-road: transversal complexity in road networks

A geometric graph is a graph embedded in the plane with vertices at points and edges drawn as curves (which are usually straight line segments) between those points. The average transversal complexity of a geometric graph is the number of edges of that graph that are crossed by random line or line segment.In this paper, we study the average transversal complexity of road networks. By viewing road networks as multiscale-dispersed graphs, we show that a random line will cross the edges of such a graph O(√n) times on average. In addition, we provide by empirical evidence from experiments on the road networks of the fifty states of United States and the District of Columbia that this bound holds in practice and has a small constant factor. Combining this result with data structuring techniques from computational geometry, allows us to show that we can then do point location and ray-shooting navigational queries with respect to road networks in O(√n log n) expected time. Finally, we provide empirical justification for this claim as well.
Intramolecular C(sp3)–H amination

Increasing interest in C(sp3)–H bond functionalization has led to a multitude of recent advances in intramolecular C(sp3)–H amination. Direct, intramolecular C(sp3)–N bond-forming processes provide expedient access to a range of azacycles without the need for prefunctionalized amine precursors such as aminoaldehydes, aminoalkyl halides or aminoalkenes. Some of these methods have been successfully applied to the synthesis of complex natural products. This Perspective provides a historical context for these methods and describes recent contributions, as well as the remaining challenges to intramolecular C(sp3)–H amination.
Error Equations of Inertial Navigation with Special Application to Orbital Determination and Guidance

Abstract The complete error equations are derived for an inertial navigator operating in a vehicle flying in an arbitrary elliptical orbit. The derivation incorporates a new notation that makes it easy to obtain the basic results in a correct manner. It is shown that the error equations of any inertial navigator (either on earth or in orbit) are identical to the equations for the perturbations of the coordinates of a satellite. When the normalized orbital error equations are coordinatized in a locally level reference frame, they become the Tschauner-Hempel equations. The structure of the solutions of the Tschauner-Hempel equations is discussed in detail, and a partially closed form (sampled data solution) for the case of periodic error sources is presented. A number of typical solutions for various error sources are given, and the problem of reducing these errors by various modes of operation is discussed.
The Biographical Inventory in Naval Aviation Selection: Inside the Black Box

A biographical inventory has been used in the selection of students for naval aviation training since World War II, and its validity in predicting their retention in this training has been well established. This study investigated the constructs underlying the inventory and their relations to student retention criteria. A factor analysis of the items on the inventory for student pilots identified five factors. One factor, being a commissioned officer, appeared to account for the inventory's validity.
Principal axis misalignment control for deconing of spinning spacecraft

Deconing controllers are developed for a spinning spacecraft, where the control mechanism is that of axial or radial moving masses that are used to produce intentional, transient principal axis misalignments. A single mass axial controller issued to motivate the concept, and then axial and radial dual mass controllers are described. The two mass problem is of particular interest since spacecraft imbalances can be simultaneously removed with the same control logic. Each controller is tested via simulation for its ability to eliminate existing coning motion for a range of spin rates. Both controllers are developed via a linear-quadratic-regulator synthesis procedure, which is motivated by their multi-input/multi-output nature. The dynamic coupling in the radial two mass control problem introduces some particularly interesting design complications. 10 refs.
Identification of a moving object's velocity with a fixed camera

In this paper, a continuous estimator strategy is utilized to asymptotically identify the six degree-of-freedom velocity of a moving object using a single fixed camera. The design of the estimator is facilitated by the fusion of homography-based techniques with Lyapunov design methods. Similar to the stereo vision paradigm, the proposed estimator utilizes different views of the object from a single camera to calculate 3D information from 2D images. In contrast to some of the previous work in this area, no explicit model is used to describe the movement of the object; rather, the estimator is constructed based on bounds on the object's velocity, acceleration, and jerk.
Some physics and system issues in the security analysis of quantum key distribution protocols

In this paper, we review a number of issues on the security of quantum key distribution (QKD) protocols that bear directly on the relevant physics or mathematical representation of the QKD cryptosystem. It is shown that the cryptosystem representation itself may miss out many possible attacks, which are not accounted for in the security analysis and proofs. Hence, the final security claims drawn from such analysis are not reliable, apart from foundational issues about the security criteria that are discussed elsewhere. The cases of continuous-variable QKD and multi-photon sources are elaborated upon.
The quantum hydrodynamic model for semiconductor devices

The classical hydrodynamic equations can be extended to include quantum effects by incorporating the first quantum corrections. These quantum corrections are $O( {\hbar ^2 } )$. The full three-dimensional quantum hydrodynamic (QHD) model is derived for the first time by a moment expansion of the Wigner–Boltzmann equation. The QHD conservation laws have the same form as the classical hydrodynamic equations, but the energy density and stress tensor have additional quantum terms. These quantum terms allow particles to tunnel through potential barriers and to build up in potential wells.The three-dimensional QHD transport equations are mathematically classified as having two Schrodinger modes, two hyperbolic modes, and one parabolic mode. The one-dimensional steady-state QHD equations are discretized in conservation form using the second upwind method.Simulations of a resonant tunneling diode are presented that show charge buildup in the quantum well and negative differential resistance (NDR) in the current-v...
Evidence for an Impact Origin of the Pretoria Salt Pan, South Africa

THE Pretoria Salt Pan, 40 km north-west of Pretoria, South Africa, is a nearly circular crater about 1,140 m in diameter excavated in the red granite of the Bushveld Complex. The floor is 60 m below the general ground level and is underlain by at least 70 m of saline clay beds; a rim 15–60 m high surrounds the crater. The preservation of the rim, which consists in part of loose fragmental material, indicates a young age, probably Quaternary. The salt pan is thus an anomaly in the flat and geologically long quiescent terrain of the Bushveld. Wagner concluded after a thorough study that the crater was a volcanic caldera1. An alternative hypothesis, that it is an impact crater, was proposed by Rohleder as a reinterpretation of Wagner's observations2.
Future boundary conditions in de Sitter space

We consider asymptotically future de Sitter spacetimes endowed with an eternal observatory. In the conventional descriptions, the conformal metric at the future boundary $ {\mathcal{I}^{ + }} $ is deformed by the flux of gravitational radiation. We however impose an unconventional future “Dirichlet” boundary condition requiring that the conformal metric is flat everywhere except at the conformal point where the observatory arrives at $ {\mathcal{I}^{ + }} $ . This boundary condition violates conventional causality, but we argue the causality violations cannot be detected by any experiment in the observatory. We show that the bulk-to-bulk two-point functions obeying this future boundary condition are not realizable as operator correlation functions in any normalizable de Sitter invariant vacuum, but they do agree with those obtained by double analytic continuation from anti-de Sitter space.
Graphics for free

Students find computer graphics one of the most interesting topics in computer science. Unfortunately, writing programs with graphics requires understanding concepts that are usually beyond the scope of an introductory computer science course. For example, in Windows 95, a program that uses graphics must have an event loop that dispatches messages to the appropriate handler. Event loops, messages, and handlers are well beyond the grasp of someone just learning about variables! Consequently, programming assignments for introductory courses tend to use no graphics, or simple ANSI graphics (see, e.g. Feldman and Koffman [1]). These programs compare unfavorably to the graphics of games most students are accustomed to using, and motivation to program in an introductory course may be lost.Ideally, we would like to be able to have students write programs that have more appealing interfaces, yet do not require a large amount of additional conceptual complexity. In fact, the best case would be to have the student write a program as if it were a simple text-based program, and have the compiler automatically add a graphical interface. Languages that provide overloading, such as Ada 95, allow us to accomplish precisely that.This paper describes a library, Graphics_110 (named in honor of our introductory course, CS 110), which, using overloading, replaces the standard I/O libraries in Ada 95 (Ada.Text_IO, Ada.Float_Text_IO, and Ada.Integer_Tex_IO). By following a simple contract and replacing calls to the standard libraries with calls to Graphics_110, the student obtains a program with a Windows-style interface without ever having to worry about the implementation details. Although we use Ada 95 for this paper, the ideas extend to any programming language that provides subtypes and overloading.The next section describes the "contract" the programmer must follow to use the library and the third section describes the implementation of Graphics_110. In each section, we describe how we used Graphics_110 with a battleship game implemented in our introductory course. The final section presents conclusions and ideas for future work.
Guidance and targeting for the strategic target system

Guidance algorithms and targeting procedures for the Strategic Target System (STARS) launch vehicle are described. The STARS vehicle is a three-stage booster, based partly on retired Polaris A3 missile assets, which is intended to support development and testing of the Strategic Defense Initiative by delivering target payloads to the vicinity of the Kwajalein Atoll. STARS will be launched from the Kauai Test Facility located on Kauai, Hawaii. The STARS guidance objective is to deliver payloads to a prescribed target location with intercontinental ballistic missile re-entry conditions. The guidance problem is complicated by the fact that all three stages lack thrust termination or other velocity control mechanisms, and by range safety requirements for one or more out-of-plane turns. Mission objectives are achieved with a combination of guidance algorithms. The original Polaris guidance is used during the atmospheric ascent phase. The powered explicit guidance used by the Space Shuttle is later employed to execute an out-of-plane turn and to place the third stage as closely as possible onto the desired coast trajectory. Third-stage guidance is a modified Lambert procedure formulated to eliminate the target miss due to off-nominal ascent phase performance.
On the (non)rigidity of the Frobenius endomorphism over Gorenstein rings

It is well-known that for a big class of local rings of positive characteristic, including complete intersection rings, the Frobenius endomorphism can be used as a test for finite projective dimension. In this paper, we exploit this property to study the structure of such rings. One of our results states that the class groups cannot have any p-torsion, thus providing a purely algebraic proof of that fact for complete intersections, first given in SGA. Our method also leads to many simply constructed examples where rigidity for the Frobenius endomorphism does not hold, even when the rings are Gorenstein with isolated singularity. This is in stark contrast to the situation for complete intersection rings. Also, a related length criterion for modules of finite length and finite projective dimension is discussed towards the end.
Investment in Cellulosic Biofuel Refineries: Do Waivable Biofuel Mandates Matter?

We develop a conceptual model to study the impact of mandate policies on stimulating investment in cellulosic biofuel refineries. In a two-period framework, we compare the first-period investment level (FIL) under three scenarios: laissez-faire, non-waivable mandate (NWM) policy, and waivable mandate (WM) policy. Results show that when plant-level marginal costs are increasing then both NWM policy and WM policy may stimulate FIL. The WM policy has a smaller impact than does the NWM policy. When the plant-level marginal costs are constants, however, WM policy does not increase FIL but does increase the expected profit of more efficient investors. Copyright 2012, Oxford University Press.
Quasiparticle energy bands of NiO in the GW approximation

We present a first-principles study of the quasiparticle excitations spectrum of NiO. The calculations are performed using the spin-polarized GW approximation in a plane-wave basis set with ab initio pseudopotentials. We find a feature in the band structure which can explain both an absorption edge of 3.1 eV in optical measurements and an energy gap of 4.3 eV found in XPS/BIS measurements. The calculated quasiparticle density of states shows that the oxygen 2p peaks overlap with the satellite structure at similar to 8 eV below the Fermi level. Finally, we discuss the difference between this work and two previous quasiparticle energy calculations.
Acoustic-Vortex Interactions and Low-Frequency Oscillations in Axisymmetric Combustors

Time-dependent, compressible numerical simulations have been performed to study the flowfields in an idealized ramjet consisting of an axisymmetric inlet and a combustor. The simulations indicate strong coupling between the flowfield and the acoustics of both the inlet and the combustor. For the cases studied, forcing at the first longitudinal acoustic mode of the combustor induces vortex rollup near the entrance to the combustor at the forcing frequency. A low-frequency oscillation is also observed in all of the simulations. Pressure fluctuations in the inlet indicate that the low frequency corresponds to a quarter-wave mode in the inlet. Changing the length of the inlet appropriately changes the observed low frequency. The merging pattern of the vortices in the combustor is modified significantly when either the acoustics of the combustor or that of the inlet are changed. These merging patterns are explained on the basis of an interaction between the vortex-rollup frequency and the acoustic modes of the inlet and combustor.
Entanglement evolution in the presence of decoherence

The entanglement of two qubits, each defined as an effective two-level, spin 1/2 system, is investigated for the case that the qubits interact via a Heisenberg XY interaction and are subject to decoherence due to population relaxation and thermal effects. For zero temperature, the time-dependent concurrence is studied analytically and numerically for some typical initial states, including a separable (unentangled) initial state. An analytical formula for non-zero steady state concurrence is found for any initial state, and optimal parameter values for maximizing steady state concurrence are given. The steady state concurrence is found analytically to remain non-zero for low, finite temperatures. We also identify the contributions of global and local coherence to the steady state entanglement.
Cross-ratios and angles determine a polygon

We prove that a unique simple polygon is determined, up to similarity, by the interior angles at its vertices and the cross-ratios of diagonals of any given triangulation. (The cross-ratio of a diagonal is the product of the ratio of edge lengths for the two adjacent triangles.) This establishes a conjecture of Driscoll and Vavasis, and shows the correctness of a key step of their algorithm for computing Schwarz—Christoffel transformations mapping a disk to a polygon.
THE TURBULENT WARM IONIZED MEDIUM: EMISSION MEASURE DISTRIBUTION AND MHD SIMULATIONS

We present an analysis of the distribution of Hemission measures for the warm ionized medium (WIM) of the GalaxyusingdatafromtheWisconsinHMapper(WHAM)NorthernSkySurvey.OursampleisrestrictedtoGalactic latitudes jbj > 10 � .Weremovedsightlinesintersecting19high-latitudeclassicalHiiregions,leavingonlysightlines that sample the diffuse WIM. The distribution of EM sin jbjfor the diffuse WIM sample is poorly characterized by a single normal distribution, but is extraordinarily wellfit by a lognormal distribution, with hlog EM sin jbj(pc cm � 6 ) � 1 i¼ 0:146 � 0:001 and standard deviationlog EM sin jbj ¼ 0:190 � 0:001. The value of log EM sin jbj hi drops from 0:260 � 0:002 at Galactic latitude 10 < jbj < 30 to 0:038 � 0:002 at Galactic latitude 60 < jbj < 90. The distribution maywidenslightly atlowGalacticlatitude.WecomparetheobservedEMdistributionfunctiontothepredictionsof three- dimensional magnetohydrodynamic simulations of isothermal turbulence within a nonstratified interstellar medium. We find that the distribution of EM sin jbj is well described by models of mildly supersonic turbulence with a sonic Mach number of � 1.4Y2.4. The distribution is weakly sensitive to the magnetic field strength. The model also successfully predictsthedistributionof dispersionmeasuresof pulsarsandHlineprofiles.InthebestfittingmodeltheturbulentWIM occupies a vertical path length of 400Y500 pc within the 1.0Y1.8 kpc scale height of the layer. The WIM gas has a lognormal distribution of densities with a most probable electron density npk � 0:03 cm � 3 . We also discuss the impli- cations of these results for interpreting the filling factor, the power requirement, and the magnetic field of the WIM. Subject headingg ISM: structure — MHD — turbulence
Evidence for non-gaussian tail in 3-dimensional pion emission source at SPS

The NA49 experiment at CERN SPS has acquired a huge data set of Pb+Pb events over a broad range of energy and centrality during the last several years. This high statistics data set, coupled with a state-of-the-art analysis technique, allows for the first model-independent extraction and energy scan of 3D emission sources for pion pairs at SPS energies. These 3D pion emission sources provide new insights into the nature of a long-range source previously reported by PHENIX at RHIC. Preliminary results indicate that the pion source function is essentially Gaussian from 20 AGeV to 80 AGeV but it displays significant non-Gaussian tails at 158 AGeV.
Seniority, experience, and wages in the UK

Abstract This paper uses BHPS data to investigate the relative importance of seniority and experience in determining male wages in the UK labor market. Using both the Altonji and Shakotko instrumental variable and the Topel two-step estimation approaches, I find that for all male workers, tenure plays a modest role, increasing wages by about 1% each year over the first 10 years on the job. General labor market experience has a larger role, so that after 30 years wages have increased by about 60%. Individual and job match heterogeneity are important, and should be carefully modeled when estimating wage equations for the British labor market. These results are remarkably similar to the most recent evidence about these relationships in the US labor market. After extending the standard model to include industry and occupation experience, the estimated impact of job seniority becomes negligible for nonunion workers. Instead, the wages of nonunion workers rise because of the accumulation of general and sector-specific experience. The wages of union workers are still found to increase with job seniority over the first ten years with their employer, suggesting that if seniority matters for wages it is only for union workers.