cssi/SciSciGPT-SciSciNet huggingface dataset:
Finite Element Modeling of the First Ray of the Foot: A Tool for the Design of Interventions

Disorders of the first ray of the foot (defined as the hard and soft tissues of the first metatarsal, the sesamoids, and the phalanges of the great toe) are common, and therapeutic interventions to address these problems range from alterations in footwear to orthopedic surgery. Experimental verification of these procedures is often lacking, and thus, a computational modeling approach could provide a means to explore different interventional strategies. A three-dimensional finite element model of the first ray was developed for this purpose. A hexahedral mesh was constructed from magnetic resonance images of the right foot of a male subject. The soft tissue was assumed to be incompressible and hyperelastic, and the bones were modeled as rigid. Contact with friction between the foot and the floor or footwear was defined, and forces were applied to the base of the first metatarsal. Vertical force was extracted from experimental data, and a posterior force of 0.18 times the vertical force was assumed to represent loading at peak forefoot force in the late-stance phase of walking. The orientation of the model and joint configuration at that instant were obtained by minimizing the difference between model predicted and experimentally measured barefoot plantar pressures. The model were then oriented in a series of postures representative of push-off, and forces and joint moments were decreased to zero simultaneously. The pressure distribution underneath the first ray was obtained for each posture to illustrate changes under three case studies representing hallux limitus, surgical arthrodesis of the first ray, and a footwear intervention. Hallux limitus simulations showed that restriction of metatarsophalangeal joint dorsiflexion was directly related to increase and early occurrence of hallux pressures with severe immobility increasing the hallux pressures by as much as 223%. Modeling arthrodesis illustrated elevated hallux pressures when compared to barefoot and was dependent on fixation angles. One degree change in dorsiflexion and valgus fixation angles introduced approximate changes in peak hallux pressure by 95 and 22 kPa, respectively. Footwear simulations using flat insoles showed that using the given set of materials, reductions of at least 18% and 43% under metatarsal head and hallux, respectively, were possible.
A PROPOSED GLOSSARY OF CANCER.

Pliny the Elder (23-79 ad) is reported to have found the following epitaph on a Roman tombstone: "He died by reason of the confusion of the doctors." While such an epitaph might never be inscribed and seldom justified today, it can hardly be denied that some semantic confusion by the doctors is nevertheless still with us in medical parlance and writing. The human factors in the art of healing are so many and varied as to preclude medicine from ever becoming an exact science to the same degree as mathematics, chemistry, or physics. There is no good reason, however, why medical nomenclature and terminology should not be so exact that the reader or the listener might know literally what is meant, and what is intended to be included as well as what is to be excluded. Medical editors might well insist that authors say precisely what they mean in terms
Optimal Concentration for SU(1, 1) Coherent State Transforms and An Analogue of the Lieb-Wehrl Conjecture for SU(1, 1)

We derive a lower bound for the Wehrl entropy in the setting of SU(1, 1). For asymptotically high values of the quantum number k, this bound coincides with the analogue of the Lieb-Wehrl conjecture for SU(1, 1) coherent states. The bound on the entropy is proved via a sharp norm bound. The norm bound is deduced by using an interesting identity for Fisher information of SU(1, 1) coherent state transforms on the hyperbolic plane \({\mathbb{H}^{2}}\) and a new family of sharp Sobolev inequalities on \({\mathbb{H}^{2}}\). To prove the sharpness of our Sobolev inequality, we need to first prove a uniqueness theorem for solutions of a semi-linear Poisson equation (which is actually the Euler-Lagrange equation for the variational problem associated with our sharp Sobolev inequality) on \({\mathbb{H}^{2}}\). Uniqueness theorems proved for similar semi-linear equations in the past do not apply here and the new features of our proof are of independent interest, as are some of the consequences we derive from the new family of Sobolev inequalities.
A contribution to the chemistry of turkey eggs

Abstract 1. 1. Determination has been made of the chemical composition and caloric value of the edible portion, white, and yolk of turkey eggs, also of the constants of the yolk fat. 2. 2. The per cent. of lipins found in the yolk varied with the solvent used, the lowest value was obtained with ethyl ether, the highest with petroleum ether.
Dimensional reduction of the two Higgs doublet model at high temperature

Dimensional reduction and effective field theory methods are applied to the Two Higgs Doublet Model at finite temperature. A sequence of two effective three-dimensional field theories which are valid on successively longer distance scales is constructed. The resulting Lagrangian can be used to study different aspects of the phase transition in this model as well as the sphaleron rate immediately after the phase transition.
Photoelectron Spectroscopy of the Allyl and 2-Methylallyl Anions

The electron affinities of allyl, allyl-d5, 2-methylallyl, and 2-methylallyl-d7 radicals have been determined from the 351 nm photoelectron spectra of the allylic anions. The ions were prepared in a cooled helium flow reactor by the reaction of O- with the corresponding propene. The electron affinities found for the radicals listed above are 0.481 ± 0.008, 0.464 ± 0.006, 0.505 ± 0.006, and 0.493 ± 0.008 eV, respectively. Extensive vibrational structure is observed in all the spectra, as the CCC bending and symmetric stretching modes are activated upon photodetachment. Vibrational frequencies for these modes are obtained for all of the radicals. A second harmonic of an asymmetric CH2 rocking mode is observed in the spectra of the allyl, allyl-d5, and 2-methylallyl anions. Hot bands are used to determine the CCC bending frequencies in the allylic anions. Photoelectron angular distributions were measured for the allyl and 2-methylallyl anions. The photoelectron spectrum of allyl anion is calculated using a m...
Observations implicating vibronic coupling in covalently linked transition metal electron transfer systems

Abstract Experimental observations on the properties and photophysical behavior of several bimetallic and trimetallic donor-acceptor (D-A) complexes are considered. Photoinduced charge separation followed by back electron transfer seems to conform well to the behavior inferred from Born-Oppenheimer-based perturbation theory models when D-A coupling is weak, β DA −1 , but not when D-A coupling is very strong, β DA > 10 3 cm − . The best documented examples of deviations from the expected behavior are drawn from CNR-bridge transition metal systems, and this same class of D-A complexes also exhibits anomalous ground state properties: (a) a shift to lower energy, which is a function of D-A coupling, of the bridging CN − stretching frequency only when a donor and an acceptor are bridged; (b) a much larger than expected, (based on D-A charge transfer absorption) thermodynamic stabilization. Related behavior of strongly coupled D-A complexes with larger bridging ligands has also been reported. It is pointed out that substitution of a vibronic perturbation for the purely electronic perturbation of Born-Oppenheimer-based models can at least partially account for these observations. The vibronic model employed involves ligand to metal charge transfer (LMCT) and metal to ligand (MLCT) charge transfer interactions with nearest neighbor donor and acceptor respectively. The pertinent LMCT and MLCT parameters are, in principle, measurable, and their magnitudes seem compatible with the observed behavior. Some further implications and extensions are considered.
Epistemic Values and Information Management

The philosophy of information is concerned with the nature, management, and use of information. Thus, it should be able to help us make better decisions about how to manage information (e.g., decisions about intellectual property laws, collection development policies, and Internet evaluation techniques). These decisions have knowledge acquisition as one of their principal goals. Thus, one way to improve these decisions is to clarify our epistemic values. In this article, we combine epistemology and decision analysis in an attempt to assist people in this important task.
The learning organization: some reflections on organizational renewal

A learning organization has been defined as one in which the members continually acquire, share, and use new knowledge to adapt to an ever‐changing environment. By incorporating Peter Senge′s principles from The Fifth Discipline within the McKinsey 7‐S framework, presents a systems model of a learning organization. The addition of one “S” yields a model and this systems model is an assemblage of “best practices” in organizational effectiveness. The implementation of these best practices can help transform a traditional organization into a learning organization.
An adaptive global reduction algorithm for wormhole-routed 2D meshes

Abstract This paper presents a global reduction algorithm for wormhole-routed 2D meshes. Well-known reduction algorithms that are optimized for short vectors have complexity O(M log N), where N = n × n is the number of nodes, and M the vector length. Algorithms suitable for long vectors have complexity O(√N + M). Previously known asymptotically optimal algorithms with complexity O(log N + M) incur inherent network contention among constituent messages. The proposed algorithm adapts to the given vector length, resulting in complexities O(M log N) for short vectors, O(log N + M) for medium-sized vectors, and O(√N + M) for sufficiently long vectors. The O(√N + M) version is preferred to the O(log N + M) version for long vectors, due to its small coefficient associated with M, the dominating factor for such vectors. The algorithm is contention-free in a synchronous environment. Under asynchronous execution models, depth contention (contention among message-passing steps) may occur. However, simulation studies show that the effect of depth contention on the actual performance is negligible.
A betting interpretation for probabilities and Dempster--Shafer degrees of belief

There are at least two ways to interpret numerical degrees of belief in terms of betting: 1.You can offer to bet at the odds defined by the degrees of belief. 2.You can make the judgement that a strategy for taking advantage of such betting offers will not multiply the capital it risks by a large factor. Both interpretations can be applied to ordinary additive probabilities and used to justify updating by conditioning. Only the second can be applied to Dempster-Shafer degrees of belief and used to justify Dempster's rule of combination.
Average chemical composition of the lunar surface

The available data on the chemical composition of the lunar surface at eleven sites (3 Surveyor, 5 Apollo and 3 Luna) are used to estimate the amounts of principal chemical elements (those present in more than about 0.5% by atom) in average lunar surface material. The terrae of the moon differ from the maria in having much less iron and titanium and appreciably more aluminum and calcium.
Intra-articular block compared with conscious sedation for closed reduction of ankle fracture-dislocations. A prospective randomized trial.

Background: Ankle fracture-dislocations require urgent reduction to protect the soft tissues, to minimize articular injury, and to allow swelling to decrease. Conscious sedation is commonly used to provide analgesia for closed reduction of this injury. We hypothesized that an intra-articular block of the ankle would provide similar analgesia and the ability to reduce the ankle with a lower risk than conscious sedation. Methods: Between September 2005 and January 2007, forty-two patients with an ankle fracture-dislocation presented to our emergency department and were enrolled in a prospective randomized study. The patients were given either conscious sedation or an intra-articular lidocaine block for the reduction and for the application of a plaster splint. After the reduction maneuver, the patients used a visual analog pain scale to rate the level of pain before, during, and after the procedure, from 1 (no pain) to 10 (severe pain). The senior authors reviewed the injury and reduction radiographs to confirm the reduction of the ankle joint. Results: Twenty-one patients were randomized to each group. There was no difference in demographic data or fracture patterns between the groups. Both the sedation and the block reduced the pain to a similar degree. The pain reduction (the initial pain level minus the level of pain after medication was given or injected) was an average (and standard deviation) of 4.6 ± 3.3 for the block group and 4.2 ± 3.5 for the sedation group (p = 0.64). The average change in the level of pain between the initial presentation and during the reduction was 3.6 ± 3.8 for the block group and 4.1 ± 3.3 for the sedation group. Overall, there was no difference in analgesia provided by these two methods (p = 0.71). An acceptable reduction was achieved for forty-one of the forty-two patients with one failure in the sedation group. The average time for ankle reduction and stabilization in a splint was 81.5 minutes for the sedation group and 63.8 minutes for the block group. Conclusions: Compared with conscious sedation, an intra-articular lidocaine block provides a similar degree of analgesia and sufficient analgesia to achieve closed reduction of ankle fracture-dislocations. Level of Evidence: Therapeutic Level I. See Instructions to Authors for a complete description of levels of evidence.
Bending Properties of Wood I-Sections Fabricated with Screws and Polyurethane Adhesive

AbstractLaboratory tests were used to quantify the effects of section shape, screw density, and polyurethane adhesive use on laminated wood assembly bending strength and stiffness. Both I-shaped sections and vertically laminated rectangular sections were studied, each utilizing three 38×140-mm members. I-sections featured dimension lumber flanges screwed to laminated strand lumber (LSL) webs. In half of these assemblies, polyurethane adhesive was used in addition to screws. Only screws and dimension lumber (no LSL or adhesive) were used in fabrication of the vertically laminated assemblies. Bending strength and stiffness were significantly increased by the reconfiguration of members into an I shape. Composite action, and therefore bending strength and stiffness, was significantly increased by the addition of polyurethane adhesive to I-sections. This research presents an efficient assembly design with bending strength and stiffness values significantly higher than those of the current industry standard mec...
Outbursts by Low-Mass White Dwarfs in Symbiotic Variables

The high-resolution IUE spectra of the symbiotic variables BF Cygni and EG Andromedae are studied in order to describe the P Cygni-like features of these objects. The 10 high-dispersion IUE spectra are examined for orbital phase-dependent variations in the C IV resonance doublet in terms of velocity and/or structure. One image is found to have a strong He-II absorption feature that coincides in velocity with the C-IV absorption component in P Cygni. The absorbing material for both lines is related to outflow and P Cygni self-absorption near the hot component. The P Cygni profiles do not appear to be related to a red-giant wind nor an expanding circumbinary shell in the in both BF Cyg and EG And. Quasi-static evolutionary model calculations demonstrate an unexpected outburst behavior in response to the assumed accretion. These data are shown to be important for the study of symbiotic systems that contain low-mass white dwarfs.
Endogeneity and Empirical Accounting Research

The discussion reinforces and expands on some of the fundamental issues about endogeneity raised by Chenhall and Moers (European Accounting Review, this issue, pp. 173–195). We focus on the econometric problems researchers encounter when investigating the performance effects of some endogenous firm choice. Our points are illustrated using the classic research question about the relation between managerial equity ownership and firm value. We consider cases where ownership is treated as an exogenous, endogenous and ‘partially’ endogenous variable. We argue treating ownership as an exogenous variable is seriously flawed. Unfortunately, when ownership is at least partially endogenous, it is necessary for empirical researchers to identify exogenous variables that are the determinants of the ownership choice. This calls for better theory to guide the empirical work.
Novel reworkable fluxing underfill for board-level assembly

Underfills are traditionally applied for flip-chip applications. Recently, there has been increasing use of underfill for board-level assembly including ball grid arrays (BGAs) and chip scale packages (CSPs) to enhance reliability in harsh environments and impact resistance to mechanical shocks. The no-flow underfill process eliminates the need for capillary flow and combines fluxing and underfilling into one process step, which simplifies the assembly of underfilled BGAs and CSPs for SMT applications. However, the lack of reworkability decreases the final yield of assembled systems. In this paper, no-flow underfill formulations are developed to provide fluxing capability, reworkability, high impact resistance, and good reliability for the board-level components. The designed underfill materials are characterized with the differential scanning calorimeter (DSC), the thermal mechanical analyzer (TMA), and the dynamic mechanical analyzer (DMA). The potential reworkability of the underfills is evaluated using the die shear test at elevated temperatures. The 3-point bending test and the DMA frequency sweep indicate that the developed materials have high fracture toughness and good damping properties. CSP components are assembled on the board using developed underfill. High interconnect yield is achieved. Reworkability of the underfills is demonstrated. The reliability of the components is evaluated in air-to-air thermal shock (AATS). The developed formulations have potentially high reliability for board-level components.
Locality in theory space

Locality is a guiding principle for constructing realistic quantum field theories. Compactified theories offer an interesting context in which to think about locality, since interactions can be nonlocal in the compact directions while still being local in the extended ones. In this paper, we study locality in “theory space”, four-dimensional Lagrangians which are dimensional deconstructions of five-dimensional Yang-Mills. In explicit ultraviolet (UV) completions, one can understand the origin of theory space locality by the irrelevance of nonlocal operators. From an infrared (IR) point of view, though, theory space locality does not appear to be a special property, since the lowest-lying Kaluza- Klein (KK) modes are simply described by a gauged nonlinear sigma model, and locality imposes seemingly arbitrary constraints on the KK spectrum and interactions. We argue that these constraints are nevertheless important from an IR perspective, since they affect the four-dimensional cutoff of the theory where high energy scattering hits strong coupling. Intriguingly, we find that maximizing this cutoff scale implies five-dimensional locality. In this way, theory space locality is correlated with weak coupling in the IR, independent of UV considerations. We briefly comment on other scenarios where maximizing the cutoff scale yields interesting physics, including theory space descriptions of QCD and deconstructions of anti-de Sitter space.
Syntheses and characterizations of complex perovskite oxynitrides LaMg1/3Ta2/3O2N, LaMg1/2Ta1/2O5/2N1/2, and BaSc0.05Ta0.95O2.1N0.9

Abstract The following complex oxynitride perovskites have been prepared: LaMg1/3Ta2/3O2N, LaMg1/2Ta1/2O5/2N1/2, and BaSc0.05Ta0.95O2.1N0.9. Synchrotron X-ray powder diffraction analyses show that LaMg1/3Ta2/3O2N and LaMg1/2Ta1/2O5/2N1/2 are isostructural to the oxide La2Mg(Mg1/3Ta2/3)O6 (space group P21/n), whereas BaSc0.05Ta0.95O2.1N0.9 has a simple cubic symmetry similarly to BaTaO2N. The orderings of octahedral cations are markedly diminished in the above oxynitrides, as compared with the related oxides such as La2Mg(Mg1/3Ta2/3)O6 and Ba2ScTaO6. The optical band gaps are similar for the homologous compositions, LaMg1/3Ta2/3O2N, LaMg1/2Ta1/2O5/2N1/2 and LaTaON2 (1.9 eV), and BaSc0.05Ta0.95O2.1N0.9 and BaTaO2N (1.8 eV), while the absorption edges become broader for the complex derivatives. As revealed from the impedance spectroscopic analysis, the oxynitrides have clearly different dielectric components from those of comparable oxides containing Ta5+. Impedance spectroscopy reveals interesting capacitor geometry in BaSc0.05Ta0.95O2.1N0.9 in which the semiconducting oxynitride grains are separated by insulating secondary phases. Most notably BaSc0.05Ta0.95O2.1N0.9 has a bulk component with a high relative permittivity (κ=7300) and the grain boundary component with an even higher κ.
Dust grain orbital behavior around ceres

Abstract Many asteroids show indications they have undergone impacts with meteoroid particles having radii between 0.01 m and 1 m. During such impacts, small dust grains will be ejected at the impact site. The possibility of these dust grains (with radii greater than 2.2 μm) forming a halo around a spherical asteroid (such as Ceres) is investigated using standard numerical integration techniques. The orbital elements, positions, and velocities are determined for particles with varying radii taking into account both the influence of gravity, radiation pressure, and the interplanetary magnetic field (for charged particles). Under the influence of these forces it is found that dust grains (under the appropriate conditions) can be injected into orbits with lifetimes in excess of one year. The lifetime of the orbits is shown to be highly dependent on the location of the ejection point as well as the angle between the surface normal and the ejection path. It is also shown that only particles ejected within 10° relative to the surface tangential survive more than a few hours and that the longest-lived particles originate along a line perpendicular to the Ceres-Sun line.
Effect of color screening on heavy quarkonia Regge trajectories

Abstract Using an unquenched lattice potential to calculate the spectrum of a bottomonium-like system, we demonstrate numerically that the effect of pair creation is to produce termination of the real part of hadronic Regge trajectories, in contrast to the Veneziano model and the vast majority of phenomenological generalizations. Termination of the real part of Regge trajectories may have significant experimental consequences.
Electron radiation effects on the thermal expansion of graphite resin composites

The effects of 1 MeV electron radiation on the thermal expansion characteristics of two graphite reinforced resin matrix composite systems were studied. Specimens of both graphite/epoxy (T300/5208) and graphite/polyimide (C6000/PMR15) were irradiated to a total dose of 6 x 10 to the 9th rads at two different rates. Dynamic mechanical analyses (DMA) were performed to study changes in resin chemistry. Thermal expansion results indicate that radiation did produce permanent residual strains of up to -70 x 10 to the -6th for the graphite/epoxy when exposed to temperatures up to +280 F. However, no permaanent changes in the coefficient of thermal expansion (CTE) were observed. No permanent residual strains or changes in the CTE attributable to radiation were observed for the graphite/polyimide specimens. DMA results indicate that electron radiation caused chemical changes in the epoxy matrix. These changes resulted in a lower glass transition temperature and broader 'rubbery region' which extended into the temperature range of the thermal expansion tests.
Warfarin Pharmacology, Clinical Management, and Evaluation of Hemorrhagic Risk for the Elderly

Warfarin, a vitamin K antagonist, is currently the most extensively used oral anticoagulant world-wide. It is prescribed for a variety of indications and has undergone extensive clinical study. Still, despite wide usage and considerable accumulated data from clinical trials demonstrating efficacy for a variety of thrombotic and thromboembolic conditions, warfarin is underutilized because its management is complex for both patients and physicians. However, despite these limitations, warfarin can be managed with relative safety, even in an elderly population.
A comment on BPS states in F-theory in 8 dimensions

Abstract We study some aspects of enhanced gauge symmetries in F-theory compactified on K3. We find open string configurations connecting various 7-branes which represent stable BPS states. In this approach we recover Dn and En gauge groups previously found from an analysis of singularities of the moduli space of elliptically fibered K3 manifolds as well as examples of non-perturbative realizations of An groups.
Universally maximum flow with piecewise‐constant capacities

The maximum dynamic flow problem generalizes the standard maximum flow problem by introducing time. The object is to send as much flow from source to sink in T time units as possible, where capacities are interpreted as an upper bound on the rate of flow entering an arc. A related problem is the universally maximum flow, which is to send a flow from source to sink that maximizes the amount of flow arriving at the sink by time t simultaneously for all t ≤ T. We consider a further generalization of this problem that allows arc and node capacities to change over time. In particular, given a network with arc and node capacities that are piecewise constant functions of time with at most k breakpoints, and a time bound T, we show how to compute a flow that maximizes the amount of flow reaching the sink in all time intervals (0, t] simultaneously for all 0 < t ≤ T, in O(k 2 mnlog(kn 2/m)) time. The best previous algorithm requires O(nk) maximum flow computations on a network with (m+ n)k arcs and nk nodes.
Electromechanical simulation and testing of actively controlled rotordynamic systems with piezoelectric actuators

A method is presented for simulating the coupled 'electromechanical' system to predict rotordynamic stability and unbalance response along with control system stability. The piezoelectric actuators and their amplifiers are represented as equivalent linear electrical circuits. The electromechanical system modeling approach is utilized to correlate test results from a double overhung rotor rig. The test results also show the effectiveness of the control system for suppressing the unbalance response of two modes using active stiffness and active damping.
Gone in 15 Seconds: The Limits of Privacy Transparency and Control

Even simpler or more usable privacy controls and notices might not improve users' decision-making regarding sharing of personal information. Control might paradoxically increase riskier disclosure by soothing privacy concerns. Transparency might be easily muted, and its effect arbitrarily controlled, through simple framing or misdirections.
Charged Particle Motion in a Highly Ionized Plasma

Abstract A recently introduced method utilizing dimensional continuation is employed to compute the energy loss rate for a non-relativistic particle moving through a highly ionized plasma. No restriction is made on the charge, mass, or speed of this particle. It is, however, assumed that the plasma is not strongly coupled in the sense that the dimensionless plasma coupling parameter g = e 2 κ D / 4 π T is small, where κ D is the Debye wave number of the plasma. To leading and next-to-leading order in this coupling, d E / d x is of the generic form g 2 ln [ Cg 2 ] . The precise numerical coefficient out in front of the logarithm is well known. We compute the constant C under the logarithm exactly for arbitrary particle speeds. Our exact results differ from approximations given in the literature. The differences are in the range of 20% for cases relevant to inertial confinement fusion experiments. The same method is also employed to compute the rate of momentum loss for a projectile moving in a plasma, and the rate at which two plasmas at different temperatures come into thermal equilibrium. Again these calculations are done precisely to the order given above. The loss rates of energy and momentum uniquely define a Fokker–Planck equation that describes particle motion in the plasma. The coefficients determined in this way are thus well-defined, contain no arbitrary parameters or cutoffs, and are accurate to the order described. This Fokker–Planck equation describes the straggling—the spreading in the longitudinal position of a group of particles with a common initial velocity and position—and the transverse diffusion of a beam of particles. It should be emphasized that our work does not involve a model, but rather it is a precisely defined evaluation of the leading terms in a well-defined perturbation theory.
WET GROWTH: EFFECTS OF WATER POLICIES ON LAND USE IN THE AMERICAN WEST*

Rapid population growth and increasing water development costs have prompted many western governments to condition residential development approval on the adequacy of water supplies. We examine the effects of these regulations on housing supply in Colorado and New Mexico using fixed-effects panel regressions. Our findings suggest that price-based tools to ensure water availability may be a preferred regulatory alternative to quantity restrictions. Attempts to restrict groundwater basin access have not unambiguously corrected negative externalities related to growth. Meanwhile, Colorado cities' aggressive use of impact fees has facilitated water resource development, without limiting growth.
On Matrix–Valued Herglotz Functions

We provide a comprehensive analysis of matrix–valued Herglotz functions and illustrate their applications in the spectral theory of self–adjoint Hamiltonian systems including matrix–valued Schrodinger and Dirac–type operators. Special emphasis is devoted to appropriate matrix–valued extensions of the well–known Aronszajn–Donoghue theory concerning support properties of measures in their Nevanlinna–Riesz–Herglotz representation. In particular, we study a class of linear fractional transformations MA(z) of a given n × n Herglotz matrix M(z) and prove that the minimal support of the absolutely continuous part of the measure associated to MA(z) is invariant under these linear fractional transformations. Additional applications discussed in detail include self–adjoint finite–rank perturbations of self–adjoint operators, self–adjoint extensions of densely defined symmetric linear operators (especially, Friedrichs and Krein extensions), model operators for these two cases, and associated realization theorems for certain classes of Herglotz matrices.
Covalent interaction of ascorbic acid with natural products

While ascorbic acid (vitamin C) is mostly known as a cofactor for proline hydroxylase and as a biological antioxidant, it also forms covalent bonds with natural products which we here refer to as 'ascorbylation'. A number of natural products containing an ascorbate moiety has been isolated and characterized from a variety of biological sources, ranging from marine algae to flowering plants. Most of these compounds are formed either as a result of nucleophilic substitution or addition by ascorbate, e.g. the ascorbigens from Brassica species are ascorbylated indole derivatives. Some ascorbylated tannins appear to be formed from electrophilic addition to dehydroascorbic acid. There are also examples of annulations of ascorbate with dietary polyphenols, e.g. epigallocatechin gallate (EGCG) and resveratrol derivatives. Herein is a survey of 33 ascorbylated natural products and their reported biological activities.
A GENERALIZED POINCARÉ INEQUALITY FOR A CLASS OF CONSTANT COEFFICIENT DIFFERENTIAL OPERATORS

We study first order differential operators P = P(D) with constant coefficients. The main question is under what conditions the following full gradient L p estimate holds: We show that the constant rank condition is sufficient. The concept of the Moore-Penrose generalized inverse of a matrix comes into play.
Supernovae and the Origin of the Solar System

This review concentrates on recent ideas involving a relationship between the early solar system and supernova explosions. It summarizes briefly the data that has helped inspire those ideas. Because the true relationship is still unknown and generates controversy, the distinct ideas are introduced singly in the historical context of their origins, and the active sense of surprise and controversy is visible. Quotations from pivotal papers are used as part of the exposition. The subject involves equally the isotopic anomalies detected in meteorites and the dynamic events of galactic evolution, nucleosynthesis, and protosolar collapse. Whatever the correct situation is, new connections have been found between the origin of the elements and the formation of the solar system. The objective of this review is to enable interested space scientists to quickly identify the competing points of view and the experiments and theories that have led to them.
Second Breakdown in Power Transistors Due to Avalanche Injection

This paper studies the subject of reverse bias second breakdown both experimentally and analytically. It is seen that there is excellent correlation between theory and experiment. The conclusion of this investigation is that avalanche injection is the triggering mechanism. Further, the filamentary currents that result from this can in most cases result in device failure. It is also concluded that under fixed circuit conditions, the reverse bias second breakdown potential of a transistor is completely specified by the single parameter, Vp, which is the voltage necessary for avalanche injection.
Generating asymptotically plane wave spacetimes

In an attempt to study asymptotically plane wave spacetimes which admit an event horizon, we find solutions to vacuum Einstein's equations in arbitrary dimension which have a globally null Killing field and rotational symmetry. We show that while such solutions can be deformed to include ones which are asymptotically plane wave, they do not posses a regular event horizon. If we allow for additional matter, such as in supergravity theories, we show that it is possible to have extremal solutions with globally null Killing field, a regular horizon, and which, in addition, are asymptotically plane wave. In particular, we deform the extremal M2-brane solution in 11-dimensional supergravity so that it behaves asymptotically as a 10-dimensional vacuum plane wave times a real line.
Super-reflection in fluid discs: corotation amplifier, corotation resonance, Rossby waves and overstable modes

In differentially rotating discs with no self-gravity, density waves cannot propagate around the corotation, where the wave pattern rotation speed equals the fluid rotation rate. Waves incident upon the corotation barrier may be super-reflected (commonly referred to as corotation amplifier), but the reflection can be strongly affected by wave absorptions at the corotation resonance/singularity. The sign of the absorption is related to the Rossby wave zone very near the corotation radius. We derive the explicit expressions for the complex reflection and transmission coefficients, taking into account wave absorption at the corotation resonance. We show that for generic discs, this absorption plays a much more important role than wave transmission across the corotation barrier. Depending on the sign of the gradient of the vortensity of the disc, ξ = K 2 /(2ΩΣ) (where Ω is the rotation rate, K is the epicyclic frequency and E is the surface density), the corotation resonance can either enhance or diminish the super-reflectivity, and this can be understood in terms of the location of the Rossby wave zone relative to the corotation radius. Our results provide the explicit conditions (in terms of disc thickness, rotation profile and vortensity gradient) for which super-reflection can be achieved. Global overstable disc modes may be possible for discs with super-reflection at the corotation barrier.
The computer and its peripheral equipment

Multiplication speed was once an accurate measure of the speed of an automatic calculator, because the prominent problems of that earlier day required a lot of multiplication but had only a little data, demanded relatively little memory, and had short answers. Today, things are profoundly different. One now speaks of problems limited by tape, still others limited by printing, logic, and so forth. Behind these statements is a tacit understanding that some of these limits would recede if high speed memory were larger. This situation is discussed in this paper with particular emphasis on the peripheral equipment which surrounds the largest currently available machines.
Formal synthesis of (±)-upial. Oxidative free-radical cyclization of unsaturated 1,3-cyclohexanediones

Abstract Oxidative free-radical cyclization of 4-(3-hexcnyl)-1,3-cyclohexanedione 8 affords 85% of a mixture of 7 and 29 . Short sequences were developed to convert this mixture to 2 , a late intermediate in Taschner's synthesis of upial.
A Parametric Tongue Model for Animated Speech.

We present a tongue model for use in computer-animated speech. The model is capable of representing tongue shapes during the production of English vowels and consonants as well as general motion of the tongue. Geometrically, the model is composed of a NURBS surface with 60 control points and an 8 + 13 grid of bi-cubic patches. We also present a parameterization of the model that requires only 6 parameters for use during speech production.
Service learning and integrated, collaborative project management

This article describes the development of an undergraduate course on project management that incorporates experiential learning and service learning as the primary course learning methodology to instill in students the Project Management Institute's nine Knowledge Areas. The discussed instructional method is a dynamic and participative pedagogy. The project management course content is traditionally structured around system needs and analysis identification, functional requirements analysis, project timelines, network analysis, and project progress metrics. Introduction of service-learning projects and experiential learning pedagogies provides a pragmatic approach for applying project management concepts. This article compares and contrasts the first three offerings of this course and provides lessons learned that may be helpful to others wishing to embrace project management realism in their course work. The purpose of this article is to encourage a hands-on method for learning the nine Knowledge Areas in the undergraduate classroom.
Novel refrigerator development

Abstract In Section 1, we describe how the creation of quasiparticles by current flow through a normal-insulator-superconductor (NIS) junction degrades the cooling performance of the junction. Degradation occurs due to the absorption of recombination phonons in the normal electrode and due to a reduction in the cooling power. In Section 2, we describe how vibrations from a pulse tube mechanical cooler affect X-ray measurements performed with a superconducting tunnel junction.
Screening mechanisms and student responses in the college market

Abstract In light of the sizeable financial and time investments associated with obtaining a postsecondary degree, the choice of where to apply and enroll should be a deliberate and thoughtful process. In this paper we exploit changes in application fees and admissions essay requirements, to demonstrate that students strongly respond to small costs in the college application process. Using a new method to identify major competitors of each college, we find that these small screening mechanisms negatively impact application volume and divert student applications to colleges to which they otherwise would not have applied. There is limited evidence that measures of enrollment and retention are affected.
Multithreaded java program test generation

We describe ConTest, a tool for detecting synchronization faults in multithreaded Java™ programs. The program under test is seeded with a sleep(), yield(), or priority() primitive at shared memory accesses and synchronization events. At run time, ConTest makes random or coverage-based decisions as to whether the seeded primitive is to be executed. Thus, the probability of finding concurrent faults is increased. A replay algorithm facilitates debugging by saving the order of shared memory accesses and synchronization events.
High medieval auroral incidence over China and Japan: Implications for the medieval site of the geomagnetic pole

The catalog of historical oriental aurorae compiled by Keimatsu lists 116 aurorae from China and 31 aurorae from Japan in the period 801 to 1400 AD. The two listings have no events in common. If they are considered as independent random samples from the same population, the lack of overlapping events can be used to determine the probabilities of different medieval auroral occurrence frequencies over the China-Japan quarter. We find that there is a 95 percent probability that the average rate exceeded the inferred present rate by more than a factor of 20. This corresponds to a geomagnetic pole located in the Eastern Hemisphere displaced more than 9 degrees from the geographic pole.
Cycles in projective spaces

We prove that every possible k-cycle can be embedded into PG(n, q), for all n ≥ 3. Mathematics Subject Classification (1991). 05C38, 05B25, 51E20.
Tether satellite potential for rarefied gas aerodynamic research

Applications of the tether satellite in aerodynamic research under conditions of low-density hypervelocity flow are described. The satellite is envisioned as a spheroidal nose, slab-sided cylinder with variably swept wing, tethered to the shuttle orbiter and deployed to altitudes of about 95 km and above. Suggested experiments reflect requirements for new understanding of low-density flows and include the direct measurement of normal and tangential stress on representative aerospace surfaces, the measurements of vehicle lift, drag and pitching moment, ambient gas density and composition, surface temperatures, and wall tap and impact probe behavior. Also suggested are measurements of gas densities above the wing surfaces and on or near the stagnation line using electron-beam fluorescence methods and, where applicable, free-molecule orifice probes. Experiments proposed may be implemented without significant development of new technology.
Synthesis of 2,6‐diethyl‐3‐methacroyloxymethyl‐1,5,7,8‐tetramethylpyrromethene‐BF2 for the preparation of new solid‐state laser dyes

The synthesis of 2,6-diethyl-3-methacroyloxymethyl-1,5,7,8-tetramethylpyrromethene-BF2 (2) was carried out in straightforward fashion from 2,6-diethyl-1,3,5,7,8-pentamethylpyrromethene-BF2 (1) in three steps. The monomer unit 2 has been shown to be useful for copolymerization with methyl methacrylate for the synthesis of new solid-state optical materials. In addition, the synthesis of 1 has been modified to give greater yields of this useful laser dye. © 1997 John Wiley & Sons, Inc.
Blood Lipid Levels and Antihypertensive Therapy

The effects of elevated blood lipid concentrations on cardiovascular mortality and morbidity are reviewed, with particular emphasis on how high fat diets and antihypertensive drugs can influence the risk of developing atherosclerosis.
Bond calls, credible commitment and equity dilution: A theoretical and clinical analysis of Simultaneous Tender and Call (STAC) offers

This paper is an exploration of the ability of game theory to explain real-world corporate maneuvering. We explore this issue by investigating bond tender offers accompanied by a threat to call nontendered bonds, so called "Simultaneous Tender and Call" (STAC) offers. We argue that STACs engender a transparent game played by bondholders and shareholders. We model this game and use this model to predict the outcome of STACs. Finally, we investigate the issue of whether this theoretical model explains the outcomes of four actual STAC issues made by James River, May Department Stores, and Houston Lighting & Power Company. Our clinical analysis provides support for the explanatory power of our model. Calibrating the predictions of the model with data from these STACs, we demonstrate a correspondence between theory and actual corporate behavior. As predicted by our model, subgame perfection, or threat credibility, and preplay coordination are central to explaining the outcomes of the STACs.
Simple Closed Geodesics in Hyperbolic 3-Manifolds

The question of which Riemannian manifolds admit simple closed geodesics is still a mystery. It is not known whether all closed Riemannian manifolds contain simple closed geodesics. For closed manifolds with nontrivial fundamental group, a simple closed geodesic can always be found by taking the shortest homotopically nontrivial closed geodesic. When the manifold is closed but simply connected, the question is open for dimensions three and above. In dimension two, it is known by the theorem of Lusternik and Schnirelmann [ 6 ] (see also [ 3 ] and [ 4 ]) that the 2-sphere equipped with any smooth Riemannian metric contains at least three distinct simple closed geodesics. Non-compact manifolds do not necessarily contain closed geodesics, Euclidean space being an obvious example. Even if the manifold is not simply connected, it may not contain any simple closed geodesics, as with the hyperbolic thrice-punctured sphere. However, among the orientable, finite area, complete hyperbolic 2-manifolds, the thrice-punctured sphere is the only example that contains no simple closed geodesic. In this paper, we shall determine which orientable hyperbolic 3-manifolds do and do not contain simple closed geodesics. We shall prove that the Fuchsian group corresponding to the thrice-punctured sphere generates the only example of a complete non-elementary orientable hyperbolic 3-manifold that does not contain a simple closed geodesic. We do not assume that the manifold is geometrically finite, or even that it has finitely generated fundamental group. The simple closed geodesic which we produce arises from an interesting class of elements of the fundamental group. It is the shortest closed geodesic corresponding to a screw motion induced by the action of the fundamental group on hyperbolic 3-space. In proving our result, we use geometric methods to obtain results about isometries of hyperbolic 3-space. These results apply to elliptic, as well as to parabolic and loxodromic isometries, and we state them in full generality. A related question is whether a hyperbolic 3-manifold always contains a non-simple closed geodesic. In [ 2 ], Alan Reid and Ted Chinburg utilized arithmetic hyperbolic 3-manifold theory to construct examples of closed hyperbolic 3-manifolds in which every closed geodesic is simple. We shall be working with orientable 3-manifolds, so all of the isometries discussed will be orientation preserving.
On the Macroeconomic and Welfare Effects of Illegal Immigration

Abstract This paper uses a dynamic general equilibrium model with labor market frictions to explore the economic consequences of illegal immigration. In the baseline model, native workers and illegal foreign workers compete for jobs in the same market, but serve as imperfect substitutes in production. The calibrated model generates a U-shaped relationship between long-run domestic consumption and the population share of illegal immigrants. After taking into account both consumption and leisure, I found that an increase in illegal immigration can generate significant welfare gains for the natives. The baseline model is then extended to include heterogeneous workers in the domestic population.