cssi/SciSciGPT-SciSciNet huggingface dataset:
Performance of resistive microcalorimeters and bolometers

Despite the impressive results achieved by microcalorimeters and bolometers, their performance is still significantly worse than that predicted by Mather's ideal model (Appl. Opt. 21 (1982) 1125). The difference is due both to non-ideal effects and to excess noise of unknown origin. The non-ideal effects have been recently quantified and include hot-electron effect, absorber decoupling, thermometer non-ohmic behavior, and all related extra noise sources. The excess noise affects primarily Transition Edge Sensors (TES) and is currently under experimental and theoretical investigation. This paper reviews the origin of non-ideal effects in microcalorimeters and bolometers and their effect on energy resolution and noise equivalent power. It also reviews the results on the characterization and suppression of the excess noise in TES, and the recent theoretical investigations to explain its origin in relation to fundamental physics in superconductors.
Cosmological Constant or Intergalactic Dust? Constraints from the Cosmic Far-Infrared Background

Recent observations of Type Ia supernovae (SNe) at redshifts 0 < z < 1 reveal a progressive dimming that has been interpreted as evidence for a cosmological constant of ΩΛ ~ 0.7. An alternative explanation of the SN results is an open universe with ΩΛ = 0 and the presence of 0.1 μm dust grains with a mass density of Ωdust ~ a few × 10-5 in the intergalactic (IG) medium. The same dust that dims the SNe absorbs the cosmic UV/optical background radiation around ~1 μm, and reemits it at far-infrared (FIR) wavelengths. Here we compare the FIR emission from IG dust with observations of the cosmic microwave (CMB) and cosmic far-infrared backgrounds (FIRB) by the DIRBE/FIRAS instruments. We find that the emission would not lead to measurable distortion of the CMB, but would represent a substantial fraction (75%) of the measured value of the FIRB in the 300-1000 μm range. This contribution would be marginally consistent with the present unresolved fraction of the observed FIRB in an open universe. However, we find that IG dust probably could not reconcile the standard Ω = 1 CDM model with the SN observations, even if the necessary quantity of dust existed. Future observations, capable of reliably resolving the FIRB to a flux limit of ~0.5 mJy, along with a more precise measure of the coarse-grained FIRB, will provide a definitive test of the IG dust hypothesis in all cosmologies.
Artificial Photosynthesis for Sustainable Fuel and Chemical Production

The apparent incongruity between the increasing consumption of fuels and chemicals and the finite amount of resources has led us to seek means to maintain the sustainability of our society. Artificial photosynthesis, which utilizes sunlight to create high-value chemicals from abundant resources, is considered as the most promising and viable method. This Minireview describes the progress and challenges in the field of artificial photosynthesis in terms of its key components: developments in photoelectrochemical water splitting and recent progress in electrochemical CO2 reduction. Advances in catalysis, concerning the use of renewable hydrogen as a feedstock for major chemical production, are outlined to shed light on the ultimate role of artificial photosynthesis in achieving sustainable chemistry.
Covariance Estimation: The GLM and Regularization Perspectives

Finding an unconstrained and statistically interpretable reparameterization of a covariance matrix is still an open problem in statistics. Its solution is of central importance in covariance estimation, particularly in the recent high-dimensional data environment where enforcing the positive-definiteness constraint could be computationally expensive. We provide a survey of the progress made in modeling covariance matrices from two relatively complementary perspectives: (1) generalized linear models (GLM) or parsimony and use of covariates in low dimensions, and (2) regularization or sparsity for high-dimensional data. An emerging, unifying and powerful trend in both perspectives is that of reducing a covariance estimation problem to that of estimating a sequence of regression problems. We point out several instances of the regression-based formulation. A notable case is in sparse estimation of a precision matrix or a Gaussian graphical model leading to the fast graphical LASSO algorithm. Some advantages and limitations of the regression-based Cholesky decomposition relative to the classical spectral (eigenvalue) and variance-correlation decompositions are highlighted. The former provides an unconstrained and statistically interpretable reparameterization, and guarantees the positive-definiteness of the estimated covariance matrix. It reduces the unintuitive task of covariance estimation to that of modeling a sequence of regressions at the cost of imposing an a priori order among the variables. Elementwise regularization of the sample covariance matrix such as banding, tapering and thresholding has desirable asymptotic properties and the sparse estimated covariance matrix is positive definite with probability tending to one for large samples and dimensions.
Passive tracer dispersion with random or periodic source

In this paper, the author investigates the impact of external sources on the pattern formation and long-time behavior of concentration profiles of passive tracers in a two-dimensional shear flow. It is shown that a time-periodic concentration profile exists for time-periodic external source, while for random source, the distribution functions of all concentration profiles weakly converge to a unique invariant measure (like a stationary state in deterministic systems) as time goes to infinity.
Long-term survival, axonal growth-promotion, and myelination of Schwann cells grafted into contused spinal cord in adult rats

Schwann cells (SCs) have been considered to be one of the most promising cell types for transplantation to treat spinal cord injury (SCI) due to their unique growth-promoting properties. Despite the extensive use as donor cells for transplantation in SCI models, the fate of SCs is controversial due in part to the lack of a reliable marker for tracing the grafted SCs. To precisely assess the fate and temporal profile of transplanted SCs, we isolated purified SCs from sciatic nerves of adult transgenic rats overexpressing GFP (SCs-GFP). SCs-GFP were directly injected into the epicenter of a moderate contusive SCI at the mid-thoracic level at 1week post-injury. The number of SCs-GFP or SCs-GFP labeled with Bromodeoxyuridine (BrdU) was quantified at 5min, 1day, and 1, 2, 4, 12 and 24weeks after cell injection. Basso, Beattie, and Bresnahan (BBB) locomotor rating scale, footfall error, thermal withdrawal latency, and footprint analysis were performed before and after the SCs-GFP transplantation. After transplantation, SCs-GFP quickly filled the lesion cavity. A remarkable survival of grafted SCs-GFP up to 24weeks post-grafting was observed with clearly identified SC individuals. SCs-GFP proliferated after injection, peaked at 2weeks (26% of total SCs-GFP), decreased thereafter, and ceased at 12weeks post-grafting. Although grafted SCs-GFP were mainly confined within the border of surrounding host tissue, they migrated along the central canal for up to 5.0mm at 4weeks post-grafting. Within the lesion site, grafted SCs-GFP myelinated regenerated axons and expressed protein zero (P0) and myelin basic protein (MBP). Within the SCs-GFP grafts, new blood vessels were formed. Except for a significant decrease of angle of rotation in the footprint analysis, we did not observe significant behavioral improvements in BBB locomotor rating scale, thermal withdrawal latency, or footfall errors, compared to the control animals that received no SCs-GFP. We conclude that SCs-GFP can survive remarkably well, proliferate, migrate along the central canal, and myelinate regenerated axons when being grafted into a clinically-relevant contusive SCI in adult rats. Combinatorial strategies, however, are essential to achieve a more meaningful functional regeneration of which SCs may play a significant role.
Phase-space structure of cold dark matter halos

Abstract We discuss the extent to which the phase-space distribution of cold dark matter particles is thermalized in a galactic halo and find that there are large deviations from a thermal distribution in that the highest energy particles have discrete values of velocity. The central values and intensities of the corresponding peaks provide detailed information on the history of the Galaxy. This information becomes immediately available if a signal is found in a cavity detector of galactic halo axions.
50-dB nonlinear crosstalk suppression in a WDM analog fiber system by complementary modulation and balanced detection

We investigate, theoretically and experimentally, a novel scheme to suppress the nonlinear crosstalk between wavelengths in wavelength-division multiplexing (WDM) analog fiber systems. It is based on an improvement to a previously introduced crosstalk-suppression technique by complementary modulation of two closely spaced optical twin carriers (TCs). By combining the modulated TCs by a balanced detector (TCs-balanced detection [TC-BD]), the suppression can be improved further. We have obtained up to 50-dB crosstalk reduction at low modulation frequencies, where crosstalk is most severe, and in the most interesting region for cable television systems.
Tris(3,6-dioxaheptyl)amine: A superior complexing agent for dissolving metal reactions

Abstract Commercially available tris(3,6-dioxaheptyl)amine (TDA-1) is an effective phase transfer catalyst for reactions with sodium-potassium alloy in tetrahydrofuran. Deoxygenation of acetates, dehalogenation, and hydrolysis of tosylates and mesylates proceed in high yield. The use of a deuterated alcohol during deoxygenation reactions leads to site-specific deuteration.
Synthesis, structure, and optical properties of the quaternary seleno-gallates NaLnGa4Se8 (Ln = La, Ce, Nd) and their comparison with the isostructural thio-gallates.

Three new quaternary seleno-gallates containing rare-earth metals and sodium cations, have been synthesized by a solid-state route in evacuated quartz ampoules: NaLnGa4Se8 (Ln = La(I), Ce (II) and ...
Time-resolved electron-beam characterizations with optical transition radiation☆

Abstract Time-resolved characterizations of electron beams using optical transition radiation (OTR) as a prompt conversion mechanism have recently been extended on the Los Alamos free-electron Laser (FEL) facility 40-MeV linac. Two key timescales for rf-linac driven FELs are the mupulse (10 ps) and the macropulse (5 μs to 1 ms). In the past we have used gated, intensified cameras to select a single or few mupulses (25–400 ns gate width) out of the pulse train to evaluate submacropulse effects. Recently, we have obtained some of the first measurements of mupulse bunch length (7–10 ps) and submacropulse spatial position and profile using OTR and a Hamamatsu streak camera. Additionally, mupulse elongation effects and head-to-tail transverse kicks are reported as a function of charge.
The impact of surgical intraocular pressure reduction on visual function using various criteria to define visual field progression.

PURPOSE To examine the impact of surgical intraocular pressure (IOP) reduction on visual function using various methods to define visual field (VF) progression. METHODS A retrospective chart review was conducted on consecutive glaucoma patients who underwent surgical IOP reduction between January 1, 2002 and December 31, 2007. All subjects had glaucomatous optic neuropathy, a minimum of 5 preoperative and 5 postoperative VFs, and were followed for a minimum of 2 years both before and after surgery. VF progression was determined using guided progression analysis, linear regression analysis of the visual field index, and individual sensitivity values using Progressor software. RESULTS Seventeen eyes of 17 patients (mean age 77.9±9.9 y) were enrolled. Subjects were followed for a mean 5.8±2.4 years before surgery and 4.5±1.5 years after surgery. The mean postoperative IOP (11.3±4.2 mm Hg) and medications (1.3±1.3) were significantly (P<0.001 and P=0.01) reduced compared with before surgery (18.0±3.9 mm Hg, 2.4±0.9, respectively). The number of eyes judged to have VF progression using any method during the postoperative period (3 of 17, 17.6%) was significantly (P=0.03) reduced compared with the preoperative period (9 of 17 eyes, 52.9%). Using visual field index criteria, 8 eyes were judged to have preoperative VF progression and 1 eye had persistent VF progression during the postoperative period. None of the eyes judged to have preoperative VF progression using Early Manifest Glaucoma Trial (n=4) and Progressor criteria (n=1) demonstrated persistent VF progression during the postoperative period. Among eyes with preoperative VF progression, the postoperative slope of mean deviation (-0.21±0.23 dB/y) was significantly (P=0.03) reduced compared with before surgery (-1.01±0.23 dB/y). CONCLUSIONS Despite differences in the criteria used to define VF progression, glaucoma surgical IOP reduction significantly reduces the incidence and rate of VF progression.
Nonparametric regression applied to quantitative structure-activity relationships

Several nonparametric regressors have been applied to modeling quantitative structure−activity relationship (QSAR) data. The simplest regressor, the Nadaraya−Watson, was assessed in a genuine multi...
Microwave-assisted methylation of phenols with DMF-DMA

We evaluated the potential of N,N-dimethylformamide dimethylacetal (DMF-DMA) as a methylating agent for a library of para-substituted phenols under microwave irradiation. The rate of reaction was dictated by the electronic nature of the para-substituent. With an electron-withdrawing group the reaction was completed within 30 min. For electron-donating groups, the reaction times were 60 min. Esterification and enamino-ketone formation was also observed with carboxylic acid and ketone functional groups, respectively.
Probabilistic behavior and information measures of sequential nanoICs

Due to many random factors from thermal fluctuation to wave interference, physical perfection in nanoICs is hard to achieve. Defects and faults arise from instability and noise-proneness on nanometer scales. This leads to unreliable and undesirable results of computation. In order to ensure more computation, techniques are necessary to cope with such errors. This can be achieved in nanotechnology using probabilistic models. In these models, it is assumed that the input and output signals are performed with probability because of noise signals, and the implemented logic function is performed within some probability because of the nature of nanoICs. In this paper, methods for computing the output probability of sequential logic nanocircuits are presented to extract information from sequential nanoICs in nanospace of a noisy environment, it is found that the most appropriate measure of information is the measure of entropy. The results of the study of probabilistic behavior and information measure of sequential nanoICs are reported with illustrative examples.
Approximability of constrained LCS

The problem Constrained Longest Common Subsequence is a natural extension to the classical problem Longest Common Subsequence, and has important applications to bioinformatics. Given k input sequences A"1,...,A"k and l constraint sequences B"1,...,B"l, C-LCS(k,l) is the problem of finding a longest common subsequence of A"1,...,A"k that is also a common supersequence of B"1,...,B"l. Gotthilf et al. gave a polynomial-time algorithm that approximates C-LCS(k,1) within a factor m@?|@S|, where m@? is the length of the shortest input sequence and |@S| is the alphabet size. They asked whether there are better approximation algorithms and whether there exists a lower bound. In this paper, we answer their questions by showing that their approximation factor m@?|@S| is in fact already very close to optimal although a small improvement is still possible:1.For any computable function f and any @e>0, there is no polynomial-time algorithm that approximates C-LCS(k,1) within a factor f(|@S|)@?m@?^1^/^2^-^@e unless NP=P. Moreover, this holds even if the constraint sequence is unary. 2.There is a polynomial-time randomized algorithm that approximates C-LCS(k,1) within a factor |@S|@?O(OPT@?loglogOPT/logOPT) with high probability, where OPT is the length of the optimal solution, OPT=0, there is no polynomial-time algorithm that approximates C-LCS(k,1) within a factor m@?^1^-^@e unless NP=P. 4.There is a polynomial-time algorithm that approximates C-LCS(k,1) within a factor O(m@?/logm@?). We also present some complementary results on exact and parameterized algorithms for C-LCS(k,1).
Ceramic thermal-barrier coatings for cooled turbines

Ceramic thermal-barrier coatings on hot engine parts have the potential to reduce metal temperatures, coolant requirements, cost, and complexity of the cooling configuration, and to increase life, turbine efficiency and gas temperature. Coating systems consisting of a plasma-sprayed layer of zirconia stabilized with either yttria, magnesia or calcia over a thin alloy bond coat have been developed, their potential analyzed and their durability and benefits evaluated in a turbojet engine. The coatings on air-cooled rotating blades were in good condition after completing as many as 500 two-minute cycles of engine operation between full power at a gas temperature of 1644 K and flameout, or as much as 150 hours of steady-state operation on cooled vanes and blades at gas temperatures as high as 1644 K witn 35 start and stop cycles. On the basis of durability and processing cost, the yttria-stabilized zirconia was considered the best of the three coatings investigated.
The synthesis of 11-oxabicyclo[6.2.1]undecenone derivatives

Abstract 11-Oxabicyclo[6.2.1]undecenone derivatives 16 and 17 were synthesized via cycloalkylation of appropriately substituted monocyclic 3(2H)-furanone derivatives.
Deflection and fragmentation of near-Earth asteroids

The collision with Earth of near-Earth asteroids or comet nuclei poses a potential threat to mankind. Objects about 100 m in diameter could be diverted from an Earth-crossing trajectory by the impact of a rocket-launched mass, but for larger bodies nuclear explosions seem to be the only practical means of deflection. Fragmentation of the body by nuclear charges is less efficient or secure.
FinFETs - Technology and circuit design challenges

It took quarter of a century for multi-gate transistor to make it from first demonstration in research to a product - 22nm technology node microprocessor in 2012. FinFETs offer superior performance over incumbent planar devices due to their significantly improved electrostatics. FinFET technology faced two key barriers to their implementation in products: demanding process integration and its significant impact on layout and circuit design methodology. In this paper we focus on challenges and tradeoffs in both of these areas. Fin shape, pitch, isolation, doping, crystallographic orientation and stressing as well as device parasitics, performance and patterning approaches will be discussed. Implementation of high mobility materials for finFET devices will also be briefly reviewed as well as design challenges for logic and SRAM circuits.
The matrix model for M theory as an exemplar of trace (or generalized quantum) dynamics

Abstract We show that the recently proposed matrix model for M theory obeys the cyclic trace assumptions underlying generalized quantum or trace dynamics. This permits verification of supersymmetry as a matrix calculation, using only the cyclic property of the trace, and allows a direct matrix calculation of the supercharge density algebra by using the generalized Poisson bracket, in a basis-independent manner that makes no reference to individual matrix elements. Our results are a special case of a general result presented elsewhere, that all rigid supersymmetry theories can be extended to give supersymmetric trace dynamics theories, in which supersymmetry of the action can be verified by cyclic permutation of noncommuting operators under the trace, and in which the supersymmetry algebra is represented by the generalized Poisson bracket of trace supercharges.
Localizable entanglement in antiferromagnetic spin chains

Antiferromagnetic spin chains play an important role in condensed matter and statistical mechanics. Recently $\mathit{XXX}$ spin chain was discussed in relation to information theory. Here we consider localizable entanglement. It is how much entanglement can be localized on two spins by performing local measurements on other individual spins (in a system of many interacting spins). We consider the ground state of antiferromagnetic spin chain. We study localizable entanglement [represented by concurrence] between two spins. It is a function of the distance. We start with isotropic spin chain. Then we study effects of anisotropy and magnetic field. We conclude that anisotropy increases the localizable entanglement. We discovered high sensitivity to a magnetic field in cases of high symmetry. We also evaluated concurrence of these two spins before the measurement to illustrate that the measurement raises the concurrence.
Scaling of fracture strength in disordered quasi-brittle materials

This paper presents two main results. The first result indicates that in materials with broadly distributed microscopic heterogeneities, the fracture strength distribution corresponding to the peak load of the material response does not follow the commonly used Weibull and (modified) Gumbel distributions. Instead, a lognormal distribution describes more adequately the fracture strengths corresponding to the peak load of the response. Lognormal distribution arises naturally as a consequence of multiplicative nature of large number of random distributions representing the stress scale factors necessary to break the subsequent “primary” bond (by definition, an increase in applied stress is required to break a “primary” bond) leading up to the peak load. Numerical simulations based on two-dimensional triangular and diamond lattice topologies with increasing system sizes substantiate that a lognormal distribution represents an excellent fit for the fracture strength distribution at the peak load. The second significant result of the present study is that, in materials with broadly distributed microscopic heterogeneities, the mean fracturestrength of the lattice system behaves as \(\mu _f = \tfrac{{\mu _{_f }^* }} {{(LogL)^\psi }} + \tfrac{c} {L}\), and scales as \(\mu _f \approx \tfrac{1} {{(LogL)^\psi }}\) as the latticesystem size, L, approaches infinity.
Stereospecific synthesis of PAF analogues. Preparation of 1-hexadecyl 2-thioacetyl-2-deoxyglycerophosphocholine (2-ThioPAF)

Abstract A new stereospecific synthesis of ether-phosholipids leading to 2-ThioPAF is reported.
Catalytic C-O Bond Cleavage of 2-Aryloxy-1-arylethanols and Its Application to the Depolymerization of Lignin-Related Polymers

A ruthenium-catalyzed, redox neutral C−O bond cleavage of 2-aryloxy-1-arylethanols was developed that yields cleavage products in 62−98% isolated yield. This reaction is applicable to breaking the key ethereal bond found in lignin-related polymers. The bond transformation proceeds by a tandem dehydrogenation/reductive ether cleavage. Initial mechanistic investigations indicate that the ether cleavage is most likely an organometallic C−O activation. A catalytic depolymerization of a lignin-related polymer quantitatively yields the corresponding monomer with no added reagent.
Fedosov *-products and quantum momentum maps

The purpose of this paper is to study various aspects of star products on a symplectic manifold related to the Fedosov method. By introducing the notion of “quantum exponential maps” we give a characterization of Fedosov connections. As an application, a geometric realization is obtained for the equivalence between an arbitrary *-product and a Fedosov one. Every Fedosov *-product is shown to be a Vey *-product. Consequently, we find that every *-product is equivalent to a Vey *-product, a classical result of Lichnerowicz. Quantization of a hamiltonian G-space, and in particular, quantum momentum maps are studied. Lagrangian submanifolds are also studied under a deformation quantization.
Prediction of Autoignition Temperatures of Organic Compounds from Molecular Structure

A quantitative structure−property relationship study is performed to develop mathematical models that relate the structures of a heterogeneous group of organic compounds to their autoignition temperature values. The molecular structures of the compounds are represented by calculated numerical descriptors which encode their topological, electronic, and geometric features. These descriptors are used to develop several multiple linear regression and computational neural network models to predict the autoignition temperatures of a data set consisting of hydrocarbons, halohydrocarbons, and compounds containing oxygen, sulfur, and nitrogen. Both genetic algorithm and simulated annealing routines are used to select subsets of descriptors based on multiple linear regression and computational neural networks. The models that are developed have predictive ability in the range of the experimental error of autoignition temperature measurements.
Effects of Heavy Elements and Excited States in the Equation of State of the Solar Interior

Although 98% of the solar material consists of hydrogen and helium, the remaining chemical elements contribute in a discernible way to the thermodynamic quantities. An adequate treatment of the heavy elements and their excited states is important for solar models that are subject to the stringent requirements of helioseismology. The contribution of various heavy elements in a set of thermodynamic quantities has been examined. Characteristic features that can trace individual heavy elements in the adiabatic exponent γ1 = (∂ ln p/∂ ln )s (s being specific entropy), and hence in the adiabatic sound speed, were searched. It has emerged that prominent signatures of individual elements exist and that these effects are greatest in the ionization zones, typically located near the bottom of the convection zone. The main result is that part of the features found here depend strongly on both the given species (atom or ion) and its detailed internal partition function, whereas other features only depend on the presence of the species itself, not on details such as the internal partition function. The latter features are obviously well suited for a helioseismic abundance determination, while the former features present a unique opportunity to use the Sun as a laboratory to test the validity of physical theories of partial ionization in a relatively dense and hot plasma. This domain of plasma physics has so far no competition from terrestrial laboratories. Another, quite general, finding of this work is that the inclusion of a relatively large number of heavy elements has a tendency to smear out individual features. This affects both the features that determine the abundance of elements and the ones that identify physical effects. This property alleviates the task of solar modelers because it helps to construct a good working equation of state that is relatively free of the uncertainties from basic physics. By the same token, it makes more difficult the reverse task, which is constraining physical theories with the help of solar data.
Synthesis of RC Bandpass Filters

For the first time a method of designing RC bandpass filters is presented. The method consists of two steps. The first step is a scheme to locate the necessary poles and zeros that are RC realizable to produce certain bandpass characteristics. The second step is the synthesis of RC networks to produce these poles and zeros. In the first step, the conformal transformati \begin{equation*}s(z) = {\left(\frac{sn^{2}(z,k) - sn^{2}(\alpha{K,k})}{sn^{2}(\alpha{K,k})[1 - k^{2}sn^{2}(\alpha{K,k})sn^{2}(z,k)]}\right)}^{1/2}\end{equation*} is used to map the complex frequency s plane into a rectangle in the z plane such that the passband becomes one side, and a part of the negative real axis becomes the opposite side of the rectangle. In the z plane, if poles are located along certain portions of the border and zeros in the interior of the rectangle, certain passband and stopband behavior can be achieved. Among the useful characteristics obtainable by this scheme, the following are three outstanding examples: 1) characteristics that are equal-ripple in the passband and monotonic in the stopband; 2) characteristics that are equal-ripple in the passband and have a number of transmission zeros in the stopband; and 3) characteristics with a maximum gain at the band center and monotonic elsewhere. The steepness of attenuation outside the passband can be altered by a change in the numbers of zeros at the origin and infinity.
Canonical Perturbation of a Fast Time-Periodic Hamiltonian via Liapunov-Floquet Transformation

In this study a possible application of time-dependent canonical perturbation theory to a fast nonlinear time-periodic Hamiltonian with strong internal excitation is considered. It is shown that if the time-periodic unperturbed part is quadratic, the Hamiltonian may be canonically transformed to an equivalent form in which the new unperturbed part is time-invariant so that the time-dependent canonical perturbation theory may be successfully applied. For this purpose, the Liapunov-Floquet (L-F) transformation and its inverse associated with the unperturbed time-periodic quadratic Hamiltonian are computed using a recently developed technique. Action-angle variables and time-dependent canonical perturbation theory are then utilized to find the solution in the original coordinates. The results are compared for accuracy with solutions obtained by both numerical integration and by the classical method of directly applying the time-dependent perturbation theory in which the time-periodic quadratic part is treated as another perturbation term. A strongly excited Mathieu-Hill quadratic Hamiltonian with a cubic perturbation and a nonlinear time-periodic Hamiltonian without a constant quadratic part serve as illustrative examples. It is shown that, unlike the classical method in which the internal excitation must be weak , the proposed formulation provides accurate solutions for an arbitrarily large internal excitation.
Passive-adaptive vibration absorbers using shape memory alloys

The passive-adaptive approach to vibration control shows promise in its ability to combine the robust stability and low-complexity of passive tuned absorbers with the adaptability of active control schemes. Previous tunable vibration absorbers have been complex and bulky. Shape memory alloys (SMA) with their variable material properties, offer an alternative adaptive mechanism. Heating an SMA causes a change in the elastic modulus of the material by a factor as high as three. Incorporating SMA in parallel with traditional spring materials creates an absorber with a variable spring stiffness and a corresponding variable tuning frequency. Using on-off actuation of the SMA, discrete frequencies of tuning are obtained through the use of multiple SMA elements.
Pathogenesis of a Local Graft versus Host Reaction: Immunogenicity of Circulating Host Leukocytes

A local invasive-destructive reaction typical of that seen in allograft rejection occurs when Lewis rat spleen cells are inoculated under the capsule of Lewis kidney freshly grafted into F1 hybrid hosts. Thus the donor lymphoid cells can be immunogenically stimulated by circulating host leukocytes and the interaction of these two cell populations results in nonspecific damage to kidney parenchyma. The results indicate that passenger leukocytes in organ allografts may be important immunogenic agents.
Exact and approximate solutions of the utilization and yield equations for O2(1delta) generators

A mathematical model for the production of singlet delta oxygen from the reaction of a gas containing chlorine with the hydroperoxy ion in liquid basic hydrogen peroxide is reviewed. An exact solution for the Cl 2 utilization, O 2 ( 1 (Delta) ) yield, and efficiency of the generator is obtained in the well-stirred limit (WSL) for which the surface concentration of HO 2 - is constant. A universal set of performance curves is presented and the implications when assessing generator performance are discussed. When depletion of the surface concentration of HO 2 - is important, perturbation theory is used to obtain a solution for the generator's utilization, yield, and efficiency which is a generalization of the corresponding WSL solution. A criterion for the validity of the perturbation solution is obtained and it is shown that the performance of a rotogenerator plateaus not too far above the value of disk rotation rate predicted by this criterion. Finally an integral method is used to obtain a simple, but approximate, solution of the utilization-yield equations which applies over a wide range of operating conditions.
Tellurium in the “no-solvent” organic synthesis of allylic alcohols

Abstract Elemental tellurium can be reduced by rongalite (HOCH2SO2Na·2H2O)-KOH in the solid phase by application of ultrasound or by microwave irradiation. Without solvent, the organic substrate (eg sulfonate ester of an oxiranemethanol) is added with further sonication or irradiation to yield the desired organic product (eg allylic alcohols) and elemental Te which may be recycled. Phase-transfer conditions (water-toluene) also are satisfactory.
Preparing materials with a desired refraction coefficient

Abstract A recipe is given for creating material with a desired refraction coefficient by embedding many small particles in a given material. To implement this recipe practically, some technological problems have to be solved. These problems are formulated.
Measurement of Raman gain coefficients of hydrogen, deuterium, and methane

The authors report measurements of the absolute Raman gain of H/sub 2/ Q(1), D/sub 2/ Q(2), and CH/sub 4/ ( nu /sub 1/) at 532 nm using a Raman oscillator/amplifier arrangement. Experimentally determined steady-state gain coefficients are compared to values calculated using spectroscopic data. The dependence of the observed gain on the pressure mismatch in a Raman oscillator/amplifier system is also investigated. The measured values for hydrogen and methane are found to agree with calculated values and with the results of previous measurements. For deuterium the authors find a value of 0.45 cm/GW, which also agrees reasonably well with the calculated value. >
The J and M integrals for a cylindrical cavity in a time-harmonic wave field

Abstract The invariant integrals are being widely used in the study of defects and fracture mechanics, mostly in elastostatics. However, the properties and the interpretation of these integrals in elastodynamics, especially in the case of time-harmonic excitation, remain unexplored. This contribution is focused on the derivation of the time average J integral for a cylindrical inhomogeneity and the M integral for a cylindrical cavity placed in a monochromatic plane elastic wave. It is shown in the context of antiplane linear elasticity that the J integral, or the material force acting on the inhomogeneity, resembles the radiation pressure force exerted on a dielectric cylinder by the normally incident electromagnetic wave. Based on the existing solution of this electrodynamic problem and the corresponding acoustic problem, the J integral is expressed as a function of the nondimensional wave number in the form of the partial wave expansion of the scattering theory. Employing the same classical method as with the J integral, the closed-form solution of the time average M integral for a traction-free cavity is also obtained as a function of the nondimensional wave number. The M integral, i.e., the expansion or scalar moment per unit length on an infinitely long circular cavity, is represented in terms of the scattering phase shifts as in the case of the J integral. Alternative expressions that are more convenient for numerical calculations for the cavity are also derived for both integrals. These calculations are carried out for the J and M integrals in a wide spectrum of frequencies. Asymptotic approximations of both integrals for low and high frequencies are presented. The long wavelength approximation, including the monopole and dipole contributions, has been provided for the J integral in the form of a simple analytical expression. The value of M integral in the vanishing frequency limit is also presented. In the opposite short wavelength limit, the corresponding asymptotic values are derived for both integrals. These solutions, which are valid for the empty cavity, are extended to the case of an inviscid fluid-filled cavity. The obtained results have a variety of engineering and geophysical implications. In particular, their applications to the flaw characterization of materials and further development of non-destructive evaluation techniques are briefly discussed in light of the frequency relationships derived for the J and M integrals.
Airborne imaging spectrometer: A new tool for remote sensing

Thc first of a new class of remote sensing instruments is described. The Airborne Imaging Spectrometer represents the first use of two-dimensional integrated infrared area arrays in a scientific application. The instrument images 32 cross-track pixels simultaneously, each in 128 spectral bands la the 1.2- to 2.4-μ region. The IFOV of the instrument is 1.9 mrad per pixel and the spectral sampling interval is 9.6 nm. Plans include upgrading the detector from the current 32 × 32 element HgCdTe CCD array to a 64 × 64 element array in 1985. Science and engineering data are currently being actively gathered with the instrument.
Methods for Computing Minimum-Time Paths in Strong Winds

This paper describes methods for computing minimum-time flight paths at high altitudes in the presence of strong horizontal wind s. The first method shows how to calculate nonlinear feedback (“dynamic programming”) solutions for minimum-time flight paths. To do this the Zermelo Problem for arbitrary winds is extended from a flat earth model to a spherical earth model as a two-state problem (latit ude and longitude) with one control (heading angle). Many minimum-time paths are calculated backwards from New York JFK Airport and San Francisco International Airport to points in the continental U.S. Then the optimal heading angle and the minimum-time can be found by interpolation given the current latitude and longitude using an interpolant created by Delaunay triangulation. The second method is based on an analytical neighboring optimal control solution that computes neighboring optimal heading commands as a function of the winds along a nominal flight path. As an example, minimum-time paths to New York and San Francisco are determined for the actual jet stream winds on 14 February 2001 at 36 kft.
Durable Differentiation Strategies for Services

States that understanding of the durability of differentiation and positioning as strategies is generally limited, although these areas are of great interest to service marketers. Argues that service marketers must be aware of the need to create and implement durable strategies. Proposes a framework for identifying strategies resistant to competitive imitation, based on the isolating mechanisms idea. Gives examples of differentiation strategies useful for exploiting isolating mechanisms. Concludes that managers analysing the role of both competitive and customer‐based isolating mechanisms will be morelikely to adopt a long‐term, proactive view of service differentiation.
Trade credit in a monetary economy

Abstract This paper examines the importance of financial and technological stochastic trends in the context of a stochastic, dynamic, general equilibrium monetary economy with multiple means of payment. In contrast to earlier empirical work, we find support for both a long-run substitution condition between money, trade credit, and interest rates as well as a long-run transactions demand for alternative payments media consistent with real business cycle frameworks.
Binary Quantum Receiver Concept Demonstration

An experimental demonstration of a quantum-optimal receiver for optical binary signals, developed as a joint effort by the Jet Propulsion Laboratory and the California Institute if Technology, is described in this article. A brief summary of the classical, quantum-optimal, and quantum near optimal solutions to detecting binary signals is first presented. The components and experimental setup used to implement the receivers is then discussed. Experimental performance and results for both optimal and near-optimal receivers are presented and compared to theoretical limits. Finally, experimental shortcomings are discussed along with possible solutions and future direction.
Michigan's Minority Graduates in Practice: The River Runs Through Law School

This paper reports the results of a 1997-98 survey designed to explore the careers of the University of Michigan Law School's minority graduates from the classes of 1970 through 1996, and of a random sample of Michigan Law School's white alumni who graduated during the same years. It is to date the most detailed quantitative exploration of how minority students fare after they graduate from law school and enter law practice or related careers. The results reveal that almost all of Michigan Law School's minority graduates pass a bar exam and go on to have careers that appear successful by conventional measures. In particular, the survey indicates that minority graduates (defined so as to include graduates with African American, Latino, and Native American backgrounds) are no less successful than white graduates, whether success is measured by the log of current income, self-reported satisfaction, or an index of service contributions. Also, although an admissions index that combines LSAT scores and undergraduate grade-point average is a significant predictor of law school grades, it does not predict career success on any of our three outcome measures. Michigan is a highly selective law school; our results may not generalize to people who have graduated from other law schools.
State and Regional Variation in the Effects of Trade on Job Displacement in the US Manufacturing Sector, 1982–1999

Worker-level data from the 1984–2000 Displaced Worker Surveys are employed to examine the effects of trade on manufacturing workers’ probabilities of job displacement. Observed changes in import and export penetration rates yield increases in displacement probabilities for the North Central, Middle Atlantic and South Central regions yet lower displacement probabilities for the Plains/West and Pacific regions. Changes in import and export price indexes lead to increases in displacement probabilities for the Pacific, Southeast and Northeast regions and decreases for the South Central and Middle Atlantic regions. However, while the influences of imports and exports on job displacement vary considerably across states and regions, the estimated net effect of trade on displacement probabilities is minor, generally speaking, when compared to the combined influence of other factors.
Task-directed inverse kinematics for redundant manipulators

This paper presents kinematic algorithms for resolved-rate based inverse kinematics of redundant manipulators. Efficient and robust Jacobian and weighted damped least squares algorithms are given which provide a method that allows full utilization of the redundancy to best achieve task requirements. A nominal set of task space variables is suggested and procedures for modifying this specification or their relative priorities due to changing task requirements or events are discussed. Examples are shown using a simulation of the seven degree-of-freeom Robotics Research manipulator. These simulations demonstrate the singularity robustness of the algorithms and the ability to smoothly transition between task parameterizations and relative priorities.
The Role of Importers and Exporters in the Determination of the U.S. Tariff Preferences Granted to Latin America

Abstract This paper investigates the role played by domestic importers and foreign exporters in improving preferential access to the domestic market. To this end, the framework used in this paper extends the protection for sale analysis to explicitly model the role of domestic importers and foreign exporters in the determination of preferential trade treatment. The predictions of the model are tested using data on preferential trade between the United States and Latin American countries. The results suggest that Latin American exporters and US importers' lobbying efforts have a significant and important role in determining the extent of preferential access granted by the United States. More interestingly, these findings also show that U.S. importers capture a very substantial share of the rents generated by tariff preferences. These results therefore shed a pessimistic view on preferential trade schemes as a reliable source of gains for developing countries.
Improved Parameters for Extrasolar Transiting Planets

We present refined values for the physical parameters of transiting exoplanets, based on a self-consistent and uniform analysis of transit light curves and the observable properties of the host stars. Previously it has been difficult to interpret the ensemble properties of transiting exoplanets because of the widely different methodologies that have been applied in individual cases. Furthermore, previous studies often ignored an important constraint on the mean stellar density that can be derived directly from the light curve. The main contributions of this work are (1) a critical compilation and error assessment of all reported values for the effective temperature and metallicity of the host stars, (2) the application of a consistent methodology and treatment of errors in modeling the transit light curves, and (3) more accurate estimates of the stellar mass and radius based on stellar evolution models, incorporating the photometric constraint on the stellar density. We use our results to revisit some previously proposed patterns and correlations within the ensemble. We confirm the mass-period correlation and find evidence for a new pattern within the scatter about this correlation: planets around metal-poor stars are more massive than those around metal-rich stars at a given orbital period. Likewise, we confirm the proposed dichotomy of planets according to their Safronov number, and we find evidence that the systems with small Safronov numbers are more metal-rich on average. Finally, we confirm the trend that led to the suggestion that higher metallicity stars harbor planets with a greater heavy-element content.
Defining chimeras...and chimeric concerns.

(2003). Defining Chimeras...and Chimeric Concerns. The American Journal of Bioethics: Vol. 3, No. 3, pp. 17-20.