cssi/SciSciGPT-SciSciNet huggingface dataset:
Lithospheric thickness modeled from long-period surface wave dispersion

Abstract The behavior of surface waves at long periods is indicative of subcrustal velocity structure. Using recently published dispersion models, we invert surface wave group velocities for lithospheric structure, including lithospheric thickness, over much of the Eastern Hemisphere, encompassing Eurasia, Africa, and the Indian Ocean. Thicker lithospheres under Precambrian shields and platforms are clearly observed, not only under the large cratons (West Africa, Congo, Baltic, Russia, Siberia, India), but also under smaller blocks like the Tarim Basin and Yangtze craton. In contrast, it is found that remobilized Precambrian structures like the Saharan Shield and Sino–Korean Paraplatform do not have well-established lithospheric keels. The thinnest lithospheric thickness is found under oceanic and continental rifts, as well as along convergence zones. We compare our results to thermal models of continental lithosphere, lithospheric cooling models of oceanic lithosphere, lithosphere–asthenosphere boundary (LAB) estimates from S-wave receiver functions, and velocity variations of global tomography models. In addition to comparing results for the broad region, we examine in detail the regions of Central Africa, Siberia, and Tibet. While there are clear differences in the various estimates, overall the results are generally consistent. Inconsistencies between the estimates may be due to a variety of reasons including lateral and depth resolution differences and the comparison of what may be different lithospheric features.
Biosynthesis and structural revision of neomarinone.

The biosynthesis of the meroterpenoid neomarinone from a marine actinomycete was probed through feeding experiments with 13C-labeled precursors. NMR characterization of [U-13C6]glucose-enriched neomarinone led to the structural revision of structure 4a to 4b, which was confirmed by extensive 2D NMR spectrometry with unlabeled compound.
Regulation of Cardiac Output

MOST physicians are surprised to learn that the heart has relatively little effect on the normal regulation of cardiac output, but all the physician has to do is to look at his patients, and he will see that this is true. He will see a patient with mitral valvular disease whose heart has a maximum pumping ability no greater than one third normal, but at rest cardiac output is normal or almost normal. He will see a patient who has had a severe heart attack a day earlier but with a cardiac output now almost normal even though the maximum . . .
Intel and the myths of test

The author describes device testing at Intel, a company that tests 50 million microprocessors a year. He notes some myths that have grown up around testing and addresses the challenges facing test engineers, test system designers, and researchers.
A structural study of charge-density-wave perturbations in mixed- halide MX solids

Abstract Mixed-halide crystals have been formed by co-crystallizing pure [Pt(en)2Cl2][Pt(en)2](ClO4)4 (PtCl) and [Pt(en)2I2][Pt(en)2](ClO44(PtI), where en=1,2 diaminoethane. Single crystal X-ray diffraction reveals that these crystals are high quality. The pure PtI and PtCl materials contain chains of alternating Pt and halogen atoms that have undergone a Peierls distortion and commensurate charge disproportionation, resulting in alternating valence states on the platinum atoms: X-Pt(IV)-X…Pt(II)…X. The Peierls distortion results in a charge-density-wave (CDW), the strength of which is measured as the ratio, ϱ, of the short Pt(IV)-X bond distance to the long Pt(II)…X bond distance. PtCl is a strong CDW system with ϱ=0.750 and PtI is a weak CDW system with ϱ=0.919. The mixed-halide systems have the stoichiometry PtCl1−xIx, with x= 0.1, 0.15, 0.2, 0.3, 0.7, 0.8, 0.85, and 0.90. A chain lattice constant versus composition study strongly suggests distorted PtI and PtCl chains in these solids. A single crystal diffraction study on PtCl0.85I0.15 shows significant perturbations in the PtCl and PtI chain CDW strengths, with the PtI segment showing no Peierls distortion (ϱ=1). This control of the CDW strength, which is strongly tied to electron-electron and electron-phonon interactions in these solids, potentially allows tuning of electronic and optical properties on a nanometer scale.
NHC-catalyzed/titanium(IV)-mediated highly diastereo- and enantioselective dimerization of enals

An NHC-catalyzed, diastereo- and enantioselective dimerization of enals has been developed. The use of Ti(Oi-Pr)(4) is a key element for the reactivity and selectivity of this process. The cyclopentenes are obtained with high levels of diastereo- and enantioselectivity and their synthetic utility is demonstrated by functionalization of the product alkene.
Properties of Lead Fluorosilicate Glasses

Lead fluorosilicate glasses containing up to 25 mol% PbF2 were prepared. The dc electrical conductivity, thermal expansion, and transformation-range viscosity of these glasses indicate that they are anionic conductors and that fluorine significantly decreases the continuity of the vitreous network.
Statistical test for dynamical nonstationarity in observed time-series data

Information in the time distribution of points in a state space reconstructed from observed data yields a test for ``nonstationarity.'' Framed in terms of a statistical hypothesis test, this numerical algorithm can discern whether some underlying slow changes in parameters have taken place. The method examines a fundamental object in nonlinear dynamics, the geometry of orbits in state space, with corrections to overcome difficulties in real dynamical data which cause naive statistics to fail.
An approximate model of vortex decay in the atmosphere

An approximate analysis of atmospheric effects on wake vortex motion and decay is presented. The effects of density stratification, turbulence, and Reynolds number are combined in a single model so that the relative importance of different parameters can be determined. Predicted wake motion is shown to be in good agreement with limited data from both ground facility and flight test measurements taken under low turbulence conditions. Wake decay was found to depend strongly on both density stratification and turbulence. For typical levels of turbulence, wake decay was found to result from the 'Crow instability' except under strongly stratified conditions.
Combined skin and skin-muscle flap technique in lower blepharoplasty: a 10-year experience

Because of the important function of the pretarsal orbicularis muscle in blinking and tear drainage, the skin and skin-muscle flap technique for lower blepharoplasty was conceived to preserve the anatomical integrity of this muscle as well as its intimate relationship with the tarsal plate. The procedure involves elevating a skin flap over the pretarsal part of the orbicularis muscle followed by a skin-muscle flap at the preseptal part of the orbicularis muscle. This technique permits easy access to orbital fat pads while leaving the pretarsal orbicularis muscle intact and, in turn, facilitates the lateral suspension of the preseptal orbicularis muscle only. Trimming of the excess muscle is performed at the level of the preseptal orbicularis muscle, which is much less important functionally than the pretarsal orbicularis muscle, the part removed in the McIndoe-Beare muscle flap technique. This procedure, which has been performed on 700 eyelids (350 patients) from 1979 to the present, has successfully corrected lower eyelid deformity as a result of aging, particularly lower eyelid atonicity and infrapalpebral crease. The method also offers a safe and fast approach to the infraorbital bony structures in patients undergoing trauma operations or other surgical procedures.
Semiparametric Estimation of Regression Models for Panel Data

Linear models with error components are widely used to analyse panel data. Some applications of these models require knowledge of the probability densities of the error components. Existing methods handle this requirement by assuming that the densities belong to known parametric families of distributions (typically the normal distribution). This paper shows how to carry out nonparametric estimation of the densities of the error components, thereby avoiding the assumption that the densities belong to known parametric families. The nonparametric estimators are applied to an earnings model using data from the Current Population Survey. The model's transitory error component is not normally distributed. Use of the nonparametric density estimators yields estimates of the probability that individuals with low earnings will become high earners in the future that are much lower than the estimates obtained under the assumption of normally distributed error components.
Patient Cost-Sharing and Hospitalization Offsets in the Elderly

In the Medicare program, increases in cost sharing by a supplemental insurer can exert financial externalities. We study a policy change that raised patient cost sharing for the supplemental insurer for retired public employees in California. We find that physician visits and prescription drug usage have elasticities that are similar to those of the RAND Health Insurance Experiment (HIE). Unlike the HIE, however, we find substantial "offset" effects in terms of increased hospital utilization. The savings from increased cost sharing accrue mostly to the supplemental insurer, while the costs of increased hospitalization accrue mostly to Medicare.
Secondary antiproton production in relativistic plasmas

Angular and energy spectra of bremsstrahlung have been calculated from anisotropic electron distributions in solar flares. Results have been compared to observations of gamma-ray limb-brightening and the data on the variation of the gamma-ray spectrum with flare position on the sun.
Enantioselective Gold(I)-Catalyzed Vinylogous [3 + 2] Cycloaddition between Vinyldiazoacetates and Enol Ethers

The reaction of vinyldiazoacetates with enol ethers catalyzed by the binuclear gold complex (R)-DTBMSegphos(AuCl)2 activated by silver hexafluoroantimonate results in a highly enantioselective [3 + 2] cycloaddition. The [3 + 2] cycloaddition proceeds with dynamic kinetic resolution when the enol ether is a 4-substituted 1-(methoxymethylene)cyclohexane. The reaction is initiated by nucleophilic attack of the vinyl ethers at the vinylogous position of the gold vinylcarbene intermediate.
Preliminary testing of a Mach-scaled active rotor blade with a trailing-edge servo flap

The results of preliminary tests on an active helicopter rotor blade are presented. The blade, a Mach-scaled model of a CH-47D helicopter blade, has a discrete piezoelectric actuator embedded within the spar that controls a trailing edge flap via a pushrod. Ultimately, the blade will be tested on a helicopter rotor hover stand at MIT. In this paper, we describe the tests performed prior to hover testing. First, the actuator was tested on the bench to determine its control authority and frequency response. Second, the actuator was tested on a shake table to simulate the out-of-plane accelerations that would be encountered in a full-scale helicopter in forward flight. Third, the actuator was embedded in the model blade, and its response to low-frequency sinusoidal actuation was obtained and compared to the bench test results. Finally, the frequency response of the actuator in the blade was determined using swept sine excitation. All test results indicate that the actuator should produce the desired level of control authority in the model-scale rotor.
Gauge-invariant quark and gluon fields in QCD: dynamics, topology, and the gribov ambiguity

Abstract We review the implementation, in a temporal-gauge formulation of QCD, of the non-Abelian Gauss's law and the construction of gauge-invariant gauge and matter fields. We then express the QCD Hamiltonian in terms of these gauge-invariant operator-valued fields, and discuss the relation of this Hamiltonian and the gauge-invariant fields to the corresponding quantities in a Coulomb gauge formulation of QCD. We argue that a representation of QCD in terms of gauge-invariant quantities could be particularly useful for understanding low-energy phenomenology. We present the results of an investigation into the topological properties of the gauge-invariant fields, and show that there are Gribov copies of these gauge-invariant gauge fields, which are constructed in the temporal gauge, even though the conditions that give rise to Gribov copies do not obtain for the gauge-dependent temporal-gauge fields.
Studies on the total synthesis of tallysomycin. Synthesis of the threonylbithiazole moiety containing a structurally unique glycosylcarbinolamide.

Tallysomycins are glycopeptide antibiotics that were first isolated from fermentation broths of Streptoalloteichus hindustanus. They are structurally related to the bleomycins but contain an additional talose sugar attached via a unique glycosylcarbinolamide linkage. Herein we report the synthesis of a key tallysomycin intermediate that incorporates the glycosylcarbinolamide moiety unique to the tallysomycins.
New Compounds: Total Synthesis of dl-3a,4,6a-cis-4-(4-Carboxybutyl)-hexahydropyrrolo[3,4-d]imidazol-2-one Hydrochloride (dl-Azabiotin Hydrochloride)

Abstract The total synthesis of dl-3a,4,6a-cis-4-(4-carboxybutyl)-hexahydropyrrolo[3,4-d]imidazol-2-one hydrochloride (dl-azabiotin hydrochloride) was accomplished in a seven-step sequence from 2-ethoxycarbonylazepin-7-one.
Biomimetic Systems for Hydroxyapatite Mineralization Inspired By Bone and Enamel

1.1. Biomineralization The study of biomineralization is not only important to gain an understanding of how mineral-rich tissues are created in vivo but also because it is a great source of inspiration for the design of advanced materials.1-7 Mineralized tissues have remarkable hierarchical structures that have evolved over time to achieve great functions in a large variety of organisms. Organic phases play a key role in templating the structure of mineralized tissues; therefore, their matrices are often hybrid in composition, varying widely in the relative content of organic and inorganic substances. Understanding the complex integration of hard and soft phases that biology achieves in mineralized matrices across scales and its link to properties is knowledge of great value to materials chemistry. At the same time, the synthetic mechanisms used by biology to create mineralized matrices could also offer some useful strategies to create synthetic hybrid materials. Often, the amount of organic material utilized by Nature to modify mechanical properties of mineralized structures is vanishingly small. One example is the role of occluded proteins in the toughness of biogenic calcite.8 The study of mammalian bone and teeth in the biomineralization and biomimetic context is particularly interesting since the information derived could contribute a significant biomedical impact on therapies and strategies to repair or regenerate human mineralized tissues. This is an important area given the continually rising average life span of humans. The materials of interest could be highly sophisticated bioactive scaffolds to regenerate bone and possibly dental tissues as well. This review focuses on the formation of hydroxyapatite (HA) in synthetic systems designed primarily in the biomimetic context of bone or enamel mineralization for therapeutic approaches in repair of human tissues. Bone and enamel share the same mineral composition, HA, but have different morphologies and organic content. Enamel is almost entirely inorganic in composition, and bone has a relatively high organic composition. Knowledge acquired in this field may inspire the chemical synthesis of novel hybrid materials, including apatite-based structures for the regeneration of human bone and dental tissues.
Representational Momentum May Explain Aspects of Vowel Shifts

We present a computational model of vowel shifts, applied in particular to the Northern Cities Vowel Shift. Our model in- corporates several empirically-derived rules of vowel change. The key aspect of this model is the use of representational momentum, which, we argue, explains multiple observed fea- tures of the shift. We compare our model with data on the Northern Cities Shift spanning more than a century and show that, when representational momentum is included, the re- sults of the model match the data well. In the present work, we develop an agent-based model of the mechanism of vowel change based on empirical observa- tions by sociolinguists over many years. These observations are incorporated into our model as a system of constraints and update rules that try to preserve these constraints. One key addition we make to the model is to include representa- tional momentum, which is a psychologically documented phenomenon wherein people's memories of sequences of tones ordered by pitch exhibit overshoot. We demonstrate that if we include momentum in the mechanism of individual vowel change, it can account for the long-term population- wide shift in vowels. The mechanism of vowel change in our model is a phe- nomenon known as accommodation, which is an attempt on the part of a hearer to adjust his vowel system to match the speaker's. We apply our model to data on the Northern Cities Vowel Shift (NCVS), and show that when representational momen- tum is included, the results of the model match the data well, while they do not when representational momentum is not included. The rest of this article is organized as follows. We first present a brief overview of the Northern Cities Shift and the data. Then we discuss prior efforts to model vowel shifts. After that we present our model and experiments with and without representational momentum. We do a statistical analysis of our results to show how they compare with the data, and we end with a discussion of aspects of the shift that are and aren't explained by our model.
CHROMOSPHERIC ACTIVITY AND JITTER MEASUREMENTS FOR 2630 STARS ON THE CALIFORNIA PLANET SEARCH

We present time series measurements of chromospheric activity for more than 2600 main-sequence and subgiant stars on the California Planet Search (CPS) program with spectral types ranging from about F5V to M4V for main-sequence stars and from G0IV to about K5IV for subgiants. The large data set of more than 44,000 spectra allows us to identify an empirical baseline floor for chromospheric activity as a function of color and height above the main sequence. We define ΔS as an excess in emission in the Ca II H and K lines above the baseline activity floor and define radial velocity jitter as a function of ΔS and B – V for main-sequence and subgiant stars. Although the jitter for any individual star can always exceed the baseline level, we find that K dwarfs have the lowest level of jitter. The lack of correlation between observed jitter and chromospheric activity in K dwarfs suggests that the observed jitter is dominated by instrumental or analysis errors and not astrophysical noise sources. Thus, given the long-term precision for the CPS program, radial velocities are not correlated with astrophysical noise for chromospherically quiet K dwarf stars, making these stars particularly well suited for the highest precision Doppler surveys. Chromospherically quiet F and G dwarfs and subgiants exhibit higher baseline levels of astrophysical jitter than K dwarfs. Despite the fact that the rms in Doppler velocities is correlated with the mean chromospheric activity, it is rare to see one-to-one correlations between the individual time series activity and Doppler measurements, diminishing the prospects for correcting activity-induced velocity variations in F and G dwarfs.
The almost surely shrinking yolk

Abstract The yolk, defined by McKelvey as the smallest ball intersecting all median hyperplanes, is a key concept in the Euclidean spatial model of voting. Koehler conjectured that the yolk radius of a random sample from a uniform distribution on a square tends to zero. The following sharper and more general results are proved here: Let the population be a random sample from a probability measure μ on ℜ m . Then the yolk of the sample does not necessarily converge to the yolk of μ . However, if μ is strictly centered, i.e. the yolk radius of μ is zero, then the radius of the sample yolk will converge to zero almost surely, and the center of the sample yolk will converge almost surely to the center of the yolk of μ . Moreover, if the yolk radius of μ is nonzero, the sample yolk radius will not converge to zero if μ contains three non-collinear mass points or if somewhere it has density bounded away from zero in some ball of positive volume. All results hold for both odd and even population sizes.
The Improvisation-Efficiency Paradox in Inter-Firm Electronic Networks: Governance and Architecture Considerations:

The need to simultaneously achieve operational efficiency, while accommodating a continuous morphing of alliances and network arrangements, is a key challenge in the modern enterprise and market. Inter-firm interdependence and unpredictable market shifts heighten the need to establish an architecture and governance arrangement that permits rapid adaptation. Fully integrated firms have increasingly morphed into networks of collaborators. The demand for efficient and effective inter-firm coordination is no longer a desired condition, but essential for competitive position. Historically, the cost of this efficiency has been loss of flexibility, yet volatile markets reward efficiency and flexibility. Market trends demand an ability to improvise in the marketplace – converge execution with planning – while being simultaneously efficient. In this paper, we explore this improvisation-efficiency paradox. The architecture and governance issues are considered that seek the strengths of both effects. Efficiency need not come at a high cost in attaining the ability to be adaptive and spontaneous. We explore the key considerations of both network architecture and governance structures that characterize improvisational networks. Trade communities and trading partners establish a discipline of processes and decision rights that serve the community of collaborators.
Carbanion-mediated oxidative deprotection of non-enolizable benzylated amides

Abstract Treatment of non-enolizable N-benzyl or N-para-methoxybenzyl amides with butyllithium generates the corresponding benzylic carbanions that can be oxidized with either molecular oxygen or MoOPH; the resulting hemi-aminals suffer loss of the corresponding aldehyde generating the products of amide dealkylation.
Slowing down and reflection of waves in truncated periodic media

Abstract We consider wave propagation and scattering governed by 1-D Schrodinger operators with truncated periodic potentials. The propagation of wave packets with narrow frequency supports is studied. The goal is to describe potentials for which the group velocity (for a periodic problem) is small and the transmission coefficient for the truncated potential is not too small, i.e. to find media where a slowing down of the wave packets coexists with a transparency.
Political economy of Ramsey taxation

Abstract We study the dynamic taxation of capital and labor in the Ramsey model under the assumption that taxes and public good provision are decided by a self-interested politician who cannot commit to policies. We show that, as long as the politician is as patient as the citizens, the Chamley–Judd result of zero long-run taxes holds. In contrast, if the politician is less patient than the citizens, the best (subgame perfect) equilibrium from the viewpoint of the citizens involves long-run capital taxation.
Structural Analysis of a Cooled, Directionally Solidified Turbine Blade

Directionally solidifed, air-cooled turbine blades present new challenges to the structural design analyst. This paper describes an investigation of turbine blade failures encountered during a recent engine development program. The effect of wall tolerance variations on steady and vibratory stresses was determined using finiteelement methods (NASTRAN) combined with engine test data. This procedure successfully determined the failure mechanism and verified the subsequent redesign.
Analytical electron microscopy study of two vehicle-aged automotive exhaust catalysts having dissimilar activities

Abstract The microscopic details of fresh and vehicle-aged commercial pelleted automotive exhaust catalysts containing Pt, Pd and Rh were studied by employing analytical electron microscopy (AEM). Two different vehicle-aged samples containing similar poison levels but having different catalytic activities (denoted better and poorer) were selected for this study. The general microstructure of the supports and the noble metal particles of the two aged catalysts were found to be similar but the average noble metal particle size on the poorer catalyst (21 nm) was larger than that on the better catalyst (16 nm). These sizes represent a significant increase in particle size over that found on the fresh catalyst (8 nm). The activity of these catalysts decreases as the observed particle size increases. The fresh and better catalyst had a more uniform distribution of particle sizes over the full depth of the pellet impregnation zone while the particle size on the poorer catalyst increased significantly with depth. Nearly all the noble metal particles observed on both the fresh and the two aged catalysts were bi-or trimetallic. For each catalyst, the particle composition was a function of radial position. This radial dependence of composition is a result of the different impregnation profiles of the individual noble metals which were determined by electron probe microanalysis (EPMA). The larger Pt/Pd bimetallic particles on the better catalyst were homogeneous with little, if any, Pd enrichment of the surface. Such particles on the poorer catalyst exhibited non-uniform surface and bulk distribution of Pt and Pd. For all catalysts, the presence of Rh was readily detected by EPMA but was difficult to find in the observable noble metal particles. For both catalysts, the major poison deposits were concentrated in a zone less than 10 μm deep. Major contaminants were P, Pb, Zn, Ca and Si which were present as dense, noncrystalline deposits, often appearing as a shell covering the surface of the catalyst pellet. These observations support the pore mouth blockage model of poisoning. No information concerning the presence of poisons on the surfaces of noble metal particles was obtained.
What is democracy? A reconceptualization of the quality of democracy

Works on the quality of democracy propose standards for evaluating politics beyond those encompassed by a minimal definition of democracy. Yet, what is the quality of democracy? This article first reconstructs and assesses current conceptualizations of the quality of democracy. Thereafter, it reconceptualizes the quality of democracy by equating it with democracy pure and simple, positing that democracy is a synthesis of political freedom and political equality, and spelling out the implications of this substantive assumption. The proposal is to broaden the concept of democracy to address two additional spheres: government decision-making – political institutions are democratic inasmuch as a majority of citizens can change the status quo – and the social environment of politics – the social context cannot turn the principles of political freedom and equality into mere formalities. Alternative specifications of democratic standards are considered and reasons for discarding them are provided.
Asymmetric, Organocatalytic, Three-Step Synthesis of α-Hydroxy-(E)-β,γ-unsaturated Esters

An efficient and enantiocontrolled three-step synthesis of α-hydroxy-(E)-β,γ-unsaturated esters is reported. Enantioenriched α-selenyl aldehydes, prepared in one step by asymmetric, organocatalytic...
Toward the classification of Moufang loops of order 64

We show how to obtain all nonassociative Moufang loops of order less than 64 and 4262 nonassociative Moufang loops of order 64 in a unified way. We conjecture that there are no other nonassociative Moufang loops of order 64. The main idea of the computer search is to modify precisely one quarter of the multiplication table in a certain way, previously applied to small 2-groups.
A Neuroskeptic's Guide to Neuroethics and National Security

This article—informed by science studies scholarship and consonant with the emerging enterprise of “critical neuroscience”—critiques recent neuroscience research, and its current and potential applications in the national security context. The author expresses concern about the subtle interplay between the national security and neuroscience communities, and the hazards of the mutual enchantment that may ensue. The Bush Administration's “war on terror” has provided numerous examples of the abuse of medicine, behavioral psychology, polygraphy, and satellite imagery. The defense and national security communities have an ongoing interest in neuroscience too—in particular, neuroimaging and psychoactive drugs (including oxytocin) as aids to interrogation. Given the seductive allure of neuroscientific explanations and colorful brain images, neuroscience in a national security context is particularly vulnerable to abuse. The author calls for an urgent reevaluation of national security neuroscience as part of a br...
Permanent Magnetic Moments of a Superconducting Sphere

The magnetic flux retained by a polycrystalline sphere of pure tin has been studied by two experimental methods. It is shown that the amount of flux retained by the superconducting sphere exhibits a reproducible dependence on the temperature at which the transition is allowed to occur. The specimen shows a 99.9% Meissner effect for transitions well below the critical temperature, but near to ${T}_{c}$ the percent of residual flux increases several hundred-fold. The residual flux is constant as long as the temperature of the specimen is constant, but the flux is not necessarily conserved when the temperature is perturbed.
The Dynamics of International Capital Flows and Internal and External Balance

I. Introduction, 195. — II. Formulation of an appropriate function of international capital flow, 197. — III. Reappraisal of Mundell's assignment problem, 200. — IV. Further look into the basic stability of the system, 207.
Twenty Five Years After KLS: A Celebration of Non-equilibrium Statistical Mechanics

When Lenz proposed a simple model for phase transitions in magnetism, he couldn’t have imagined that the “Ising model” was to become a jewel in field of equilibrium statistical mechanics. Its role spans the spectrum, from a good pedagogical example to a universality class in critical phenomena. A quarter century ago, Katz, Lebowitz and Spohn found a similar treasure. By introducing a seemingly trivial modification to the Ising lattice gas, they took it into the vast realms of non-equilibrium statistical mechanics. An abundant variety of unexpected behavior emerged and caught many of us by surprise. We present a brief review of some of the new insights garnered and some of the outstanding puzzles, as well as speculate on the model’s role in the future of non-equilibrium statistical physics.
Equivalence of dipole correction and Coulomb cutoff techniques in supercell calculations

Article on the equivalence of dipole correction and Coulomb cutoff techniques in supercell calculations. In this work, the authors compare the dipole correction and Coulomb cutoff methods under the same conditions in the framework of plane-wave based density-functional theory.
WOLTER-SCHWARZSCHILD OPTICS FOR THE EXTREME ULTRAVIOLET: THE BERKELEY STELLAR SPECTROMETER AND THE EUV EXPLORER.

The design, fabrication and performance of two Wolter-Schwarzschild grazing incidence optics are described. Both telescopes have been figured by single point diamond turning and have achieved better than 15 arcsecond on-axis imaging. The telescope for the stellar spectrometer is an f/10 Type II system with an effective area of 225 cm2 at 250 A and 300 cm2 at 500 A. the primary has a maximum diameter of 38 cm and was fabricated in three elements. The copper-plated aluminum substrate was diamond turned; following nickel plating, the surface was polished and coated with evaporated gold. The performance during a sounding rocket flight is discussed. The pro-totype telescope for the Extreme Ultraviolet Explorer is an f/1.24 Type I system with an effective field of view of 5.0° diameter. The telescope has a maximum diameter of 40 cm and was fabricated as a single element. The aluminum substrate is to be diamond turned; the nickel plated surface will be polished and electroplated with gold. The design choice and defocusing optimization aimed at maximizing the field of view and number of image pixels is examined.
ON A THEOREM OF BRADEN

We give a new proof of Braden’s theorem ([Br]) about hyperbolic restrictions of constructible sheaves/D-modules. The main geometric ingredient in the proof is a 1-parameter family that degenerates a given scheme Z equipped with a $$ {\mathbb G} $$ m -action to the product of the attractor and repeller loci.
The passenger car and the greenhouse effect

Concern is mounting over the possibility of global warming from the greenhouse effect. Carbon dioxide (CO2) from the combustion of fossil fuel is a major greenhouse gas, and automobile exhaust is one of its contributors. The only way to decrease CO2 emissions from a car consuming carbonaceous fuel is to decrease its fuel consumption. The best alternative fossil fuels offer a CO2 reduction of about 20%. Without introducing any new greenhouse–gas controls, it is projected that the total greenhouse–gas contribution of the average car will be halved from recent levels just through fleet turnover and already planned elimination of the current air–conditioning refrigerant. If global warming develops into a serious problem, cars can be operated without fossil fuel. Leading options include battery–electric cars using nuclear power and engine–propelled cars burning biomass–derived alcohol or hydrogen extracted from water with solar cells or nuclear power.
Linear lesions in heart tissue using diffused laser radiation

Transmural, continuous, and linear lesions may be necessary for successful catheter ablation of cardiac arrythmias such as atrial fibrillation. Laser ablation was studied as an alternative to radiofrequency ablation, which is noted to produce superficial and discontinuous lesions as well as tissue charring and vaporization. Samples of canine myocardium were placed in a saline bath and irradiated with an 1.06- micrometer Nd:YAG laser operated in either pulsed or continuous mode. For pulsed mode, the laser pulse duration was 10 s with 10 s cooling between pulses. Laser radiation was delivered radially through diffusing optical fiber tips oriented parallel to the endocardial surface. In CW mode, transmural (6-mm-deep), linear (16-mm-long), and continuous lesions were produced using a laser power of 30 W and an irradiation time of 180 s. Peak tissue temperatures measured 51 plus or minus 1 degree Celsius at the endocardial surface, 61 plus or minus 6 degrees Celsius in the mid-myocardium, and 55 plus or minus 6 degree Celsius at the epicardial surface. There was no evidence of tissue charring or vaporization. Pulsed laser irradiation produced comparable lesion depths to CW irradiation with more uniform heating of the subsurface myocardium, but at the expense of longer operation times. Further in vivo study of laser ablation is warranted for possible clinical applications.
In-system FPGA prototyping of an itanium microarchitecture

This work is part of our on-going effort to prototype an Itanium microarchitecture on an FPGA. To conserve time and effort in model development, we described our microarchitecture in Bluespec, a synthesizable high-level hardware description language. The microarchitecture model currently supports a subset of the Itanium instruction set architecture (ISA). The model includes details such as multi-bundle instruction fetch, decode and issue, parallel pipelined execution units with scoreboarding and bypassing, and multiple levels of cache hierarchies. The microarchitecture model is synthesized and prototyped on an FPGA that interfaces directly to the memory bus of a host PC. The prototyped microprocessor core executes the supported ISA subset at 100MHz and directly references the host-PC's DRAM and I/O resources through the memory bus at up to 800MB/sec of bandwidth. This effort is a first step toward developing a convenient in-system microprocessor prototyping platform capable of executing realistic full-scale applications and operating systems.
Selenofluorenone: Synthesis and cycloaddition chemistry

Abstract Selenofluorenone, prepared from fluorenyl selenocyanate by base-induced elimination, participates efficiently in Diels-Alder cycloaddition and 1,3-dipolar cycloaddition reactions.
Synthetic collagen mimics: self-assembly of homotrimers, heterotrimers and higher order structures

Collagen is a fascinating system of proteins that undergo a multi-step, hierarchical self-assembly which starts from individual peptide chains that assemble into a canonical triple helix. These triple helices then assemble into higher order structures which are often, but not always, fibrous in nature. While collagen is the most abundant protein in the human body, the details of its structure and mechanism of assembly are surprisingly poorly understood. This critical review will focus on small peptide systems, commonly referred to as collagen mimetic peptides (CMPs) which have been used successfully to help unravel some of the mystery of this complex structure. We will discuss homotrimeric CMPs, which are the most commonly researched subject in this field, and the structure of the collagen triple helix in detail and the factors that contribute to its stabilization. We will also cover how CMPs have been used to study breaks in triple helical domains as models for connective tissue diseases and, finally, how they have been used to understand the interactions of collagenous proteins with cell-surface receptors. Additionally, we will focus on heterotrimeric CMPs, a relatively new area of collagen research. Finally, we will deal with CMPs used as models for higher level self-assembly and also as materials that are designed to mimic the function of collagens in the extracellular matrix (178 references).
Shape-Programmable Macromolecules

Proteins catalyze specific chemical reactions and carry out highly selective molecular recognition because they adopt well-defined three-dimensional structures and position chemically reactive functional groups in specific constellations. Proteins attain these well-defined structures through the complex process of protein folding. We seek to emulate these protein functions by constructing macromolecules that are easier to engineer by avoiding folding altogether. Toward that goal, we have developed an approach for the synthesis of macromolecules with programmable shapes. As described in this Account, we have constructed synthetic building blocks called bis-amino acids that we then couple through pairs of amide bonds to create water-soluble, spiroladder oligomers (bis-peptides) with well-defined three-dimensional structures. Bis-peptides use the conformational preferences of fused rings, stereochemistry, and strong covalent bonds to define their shape, unlike natural proteins and synthetic foldamers, which ...
Fraction-Dense Algebras and Spaces

A fraction-dense (semi-prime) commutative ring A with 1 is one for which the classical quotient ring is rigid in its maximal quotient ring. The fraction-dense f-rings are characterized as those for which the space of minimal prime ideals is compact and externally disconnected. For Archimedean lattice-ordered groups with this property it is shown that the Dedekind and order completion coincide. Fraction-dense spaces are defined as those for which C(X) is fraction-dense. If X is compact, then this notion is equivalent to the coincidence of the absolute of X and its quasi-F cover.
Inclination Mixing in the Classical Kuiper Belt

We investigate the long-term evolution of the inclinations of the known classical and resonant Kuiper Belt objects (KBOs). This is partially motivated by the observed bimodal inclination distribution and by the putative physical differences between the low- and high-inclination populations. We find that some classical KBOs undergo large changes in inclination over gigayear timescales, which means that a current member of the low-inclination population may have been in the high-inclination population in the past, and vice versa. The dynamical mechanisms responsible for the time variability of inclinations are predominantly distant encounters with Neptune and chaotic diffusion near the boundaries of mean motion resonances. We reassess the correlations between inclination and physical properties including inclination time variability. We find that the size-inclination and color-inclination correlations are less statistically significant than previously reported (mostly due to the increased size of the data set since previous works with some contribution from inclination variability). The time variability of inclinations does not change the previous finding that binary classical KBOs have lower inclinations than non-binary objects. Our study of resonant objects in the classical Kuiper Belt region includes objects in the 3:2, 7:4, 2:1, and eight higher-order mean motion resonances. We find that these objects (some of which were previously classified as non-resonant) undergo larger changes in inclination compared to the non-resonant population, indicating that their current inclinations are not generally representative of their original inclinations. They are also less stable on gigayear timescales.
An analysis of defect densities found during software inspections

Abstract Software inspection is a technical evaluation process for finding and removing defects in requirements, design, code, and tests. The Jet Propulsion Laboratory (JPL), California Institute of Technology, tailored Fagan's original process of software inspections to conform to its software development environment in 1987. Detailed data collected from 203 inspections during the first three years of experience at JPL included averages of staff time expended, pages covered, major and minor defects found, and inspection team size. The data were tested for homogeneity. Randomized samples belonging to the various phases or treatments were analyzed using the completely randomized block design analysis of variance (α = 0.05). The results showed a significantly higher density of defects during requirements inspections. The number of defect densities decreased exponentially as the work products approached the coding phase because defects were fixed when detected and did not migrate to subsequent phases. This resulted in a relatively flat profile for cost to fix. Increasing the pace of the inspection meeting decreased the density of defects found. This relationship held for major and minor defect densities, although it was more pronounced for minor defects.
Comparison of theoretical and experimental expansion cloud chamber nucleation rates of n-nonane

We have applied an extension of a microscopic model to account for the nucleation of n‐nonane. We have compared the nucleation rates obtained using the extended model with those of two experimental investigations. The results of the two experimental investigations are consistent. The nucleation rates predicted by the classical theory are inconsistent with experimental data and can vary by as much as 14 orders of magnitude. The extended model yields nucleation rates which are in close agreement with the two experimental works.
Developing a new quantitative account of backward masking

A new general explanation for u-shaped backward masking is analyzed and found to predict shifts in the interstimulus interval (ISI) that produces strongest masking. This predicted shift is then compared to six sets of masking data. The resulting comparisons force the general explanation to make certain assumptions to account for the data. In this way, the experimental data promote the development of a new theory of backward masking. The new theory suggests interpretations of the data that are sometimes novel, often more precise, and sometimes contrary to interpretations that are prevalent in the literature.
Integrated Aeroservoelastic Optimization: Status and Direction

The interactions of lightweight flexible airframe structures, steady and unsteady aerodynamics, and wide-bandwidth active controls on modern airplanes lead to considerable multidisciplinary design challenges. More than 25 years of mathematical and numerical methods' development, numerous basic research studies, simulations and wind-tunnel tests of simple models, wind-tunnel tests of complex models of real airplanes, as well as flight tests of actively controlled airplanes, have all contributed to the accumulation of a substantial body of knowledge in the area of aeroservoelasticity. A number of analysis codes, with the capabilities to model real airplane systems under the assumptions of linearity, have been developed. Many tests have been conducted, and results were correlated with analytical predictions. A selective sample of references covering aeroservoelastic testing programs from the 1960s to the early 1980s, as well as more recent wind-tunnel test programs of real or realistic configurations, are included in the References section of this paper. An examination of references 20-29 will reveal that in the course of development (or later modification), of almost every modern airplane with a high authority active control system, there arose a need to face aeroservoelastic problems and aeroservoelastic design challenges.
Methodological issues in health economics research relevant to women

Abstract Correct specification of a number of definitions and problems is essential for realistic and useful research in health economics. Societal values with regard to women's status and roles are reflected in current concepts, which need review. For example, health status is a concept with many applications. Two areas of health status are discussed: (i) Definitions of severity for adult males, children and adult females all reflect the female role as caretaker. (ii) Reproductive efficiency should be incorporated into a life-cycle-oriented concept of health status for women. The evaluation of patient time as an input into health care is conditioned by women's labor force participation and the extent of the earnings differential by sex. Additionally, a concept of a block of time as capital that is available for optimal reproduction or optimal career investment would be useful in tracing important effects of improved fertility-related health care and for other purposes. Specifications for a health care service and financing system that is responsive to women's health needs must include an appropriate definition of comprehensiveness in relation to fertility control and pregnancy, relative financial burdens for women based on their utilization, need, income and other characteristics, and compatibility of payment methods with health care objectives.
Phosphorus poisoning of the three-way catalyst studied by 31P NMR

Abstract Magic angle spinning 31P NMR spectroscopy is shown to be an informative technique for the study of the extent and chemistry of phosphorus poisoning of the three-way catalyst (TWC) used to control auto emissions. The NMR study of both used and fresh catalysts indicates that phosphorus is extraneous to the fresh catalyst and probably associated with the reduced catalytic activity of the aged converter. At least three different types of phosphorus compounds are observed and tentatively assigned.
Cognitive Capacity of Very Young Children

Children between 2 years, 6 months old and 3 years, 2 months old correctly discriminate the relative number of objects in two rows; between 3 years, 2 months and 4 years, 6 months they indicate a longer row with fewer objects to have "more"; after 4 years, 6 months they again discriminate correctly. The discriminative ability of the younger children shows that the logical capacity for cognitive operations exists earlier than previously acknowledged.