cssi/SciSciGPT-SciSciNet huggingface dataset:
Initial Ideals, Veronese Subrings, and Rates of Algebras

Abstract ⌉Let S be a polynomial ring over an infinite field and let I be a homogeneous ideal of S . Let T d be a polynomial ring whose variables correspond to the monomials of degree d in S . We study the initial ideals of the ideals V d ( I ) ⊂ T d that define the Veronese subrings of S / I . In suitable orders, they are easily deduced from the initial ideal of I . We show that in V d ( I ) is generated in degree ≤ max (⌉ reg( I )/ d ⌈, 2), where reg( I ) is the regularity of the ideal I . (In other words, the d th Veronese subrings of any commutative graded ring S / I has a Grobner basis of degree ≤ max (⌉( I )/ d ⌈, 2).) We also give bounds on the regularity of I in terms of the degrees of the generators of in( I ) and some combinatorial data. This implies a version of Backelin′s theorem that high Veronese subrings of any ring are homogeneous Koszul algebras in the sense of Priddy [ Trans. Amer. Math. Soc , 152 (1970), 39-60]. We also give a general obstruction for a homogeneous ideal I ⊂ S to have an initial ideal in( I ) that is generated by quadrics, beyond the obvious requirement that I itself should be generated by quadrics, and the stronger statement that S / I is Koszul. We use the obstruction to show that in certain dimensions, a generic complete intersection of quadrics cannot have an initial ideal that is generated by quadrics. For the application to Backelin′s theorem, we require a result of Backelin whose proof has never appeared. We give a simple proof of a sharpened version, bounding the rate of growth of the degrees of generators for syzygies of any multihomogenous module over a polynomial ring modulo an ideal generated by monomials, following a method of Bruns and Herzog.
X-Ray And Extreme Ultraviolet Imaging Using Layered Synthetic Microstructures

Techniques have recently been developed for the fabrication, by sputtering, of multi-layer structures in which the individual layers may have thicknesses as little as a few atomic diameters. Diffraction experiments with x-rays of wavelength ranging from less than 1 A to 113 A have shown these layered synthetic microstructures to have a high degree of perfection. They act as efficient reflectors for x-rays and EUV radiation at angles of incidence from 0o to almost 90o (extreme glancing incidence). Experimental results using normal incidence imaging optics at soft x-ray wavelengths are shown. Such optics can be used in a variety of configurations for both solar and non-solar x-ray astronomy. The advantages of two particular systems - the single mirror and the hybrid Wolter-LSM system - are discussed and performance calculations presented.© (1982) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Transition Metal-Catalyzed Formation of N-Heterocycles via Aryl- or Vinyl C–H Bond Amination

The construction of N-heterocycles remains a fertile area of research because of their ubiquitous occurrence in biologically active small molecules and materials. Their ubiquitous nature has motivated the development of methods to streamline their synthesis. Formation of the C–N bond via transition metal-functionalization of the aryl or vinyl C–H bond simplifies N-heterocycle synthesis by minimizing the manipulation of functional groups. Transition metal-catalyzed C–H bond amination can be accomplished through two strategies: the activation of the N-atom or activation of the C–H bond. This microreview examines the recent advances in applying these two strategies for the functionalization of sp2 C–H bonds and is organized by the source of nitrogen atom.
Erratum to: A hybrid keyword and patent class methodology for selecting relevant sets of patents for a technological field

This paper presents a relatively simple, objective and repeatable method for selecting sets of patents that are representative of a specific technological domain. The methodology consists of using search terms to locate the most representative international and US patent classes and determines the overlap of those classes to arrive at the final set of patents. Five different technological fields (computed tomography, solar photovoltaics, wind turbines, electric capacitors, electrochemical batteries) are used to test and demonstrate the proposed method. Comparison against traditional keyword searches and individual patent class searches shows that the method presented in this paper can find a set of patents with more relevance and completeness and no more effort than the other two methods. Follow on procedures to potentially improve the relevancy and completeness for specific domains are also defined and demonstrated. The method is compared to an expertly selected set of patents for an economic domain, and is shown to not be a suitable replacement for that particular use case. The paper also considers potential uses for this methodology and the underlying techniques as well as limitations of the methodology.
First-order melting of vortex lattice in strongly type-II three-dimensional superconductors

Abstract We calculate the transition line of the first-order melting of the vortex lattice in a three-dimensional type-II superconductor in fields of several T, using the results from the density-functional theory of vortex melting in two dimensions and a self-consistent Hartree treatment of correlations along the field. The result is in quantitative agreement with experiment. The temperature width of the hysteresis, the latent heat, the Debye-Waller factor and the magnetization at the transition are discussed.
Analysis of large-scale gene expression data

DNA microarray technology has resulted in the generation of large complex data sets, such that the bottleneck in biological investigation has shifted from data generation, to data analysis. This review discusses some of the algorithms and tools for the analysis and organisation of microarray expression data, including clustering methods, partitioning methods, and methods for correlating expression data to other biological data.
Recent Advances in Transition Metal-Catalyzed Glycosylation

Having access to mild and operationally simple techniques for attaining carbohydrate targets will be necessary to facilitate advancement in biological, medicinal, and pharmacological research. Even with the abundance of elegant reports for generating glycosidic linkages, stereoselective construction of α- and β-oligosaccharides and glycoconjugates is by no means trivial. In an era when expanded awareness of the impact we are having on the environment drives the state-of-the-art, synthetic chemists are tasked with developing cleaner and more efficient reactions for achieving their transformations. This movement imparts the value that prevention of waste is always superior to its treatment or cleanup. This review will highlight recent advancement in this regard by examining strategies that employ transition metal catalysis in the synthesis of oligosaccharides and glycoconjugates. These methods are mild and effective for constructing glycosidic bonds with reduced levels of waste through utilization of substo...
q-algebras and arrangements of hyperplanes

Abstract Varchenko's approach to quantum groups, from the theory of arrangements of hyperplanes, can be usefully applied to q-algebras in general, of which quantum groups and quantum (super) Kac–Moody algebras are special cases. New results are obtained on the classification of q-algebras, and of the Serre ideals of generalized quantum (super) Kac–Moody algebras.
The Uses of Whitham Hierarchies

We review some of the uses of Whitham hierarchies in the context of the theory of the prepotential in N = 2 supersymmetric gauge theories. We focus on the structure of the contact terms in the twisted topological theory, and on the connection between Whitham hierarchies and the u-plane integrals for higher rank gauge groups, trying to put together the different approaches involved in this connection. We also review two other uses of the Whitham hierarchies: the interpretation of the slow times as supersymmetry breaking parameters, and the new techniques to extract instanton corrections using the RG equations written in terms of theta functions.
Cell-based high-frequency IC design in scaled CMOS

This paper presents a cell-based modeling and design platform for high-frequency analog ICs to shorten design cycle time and to minimize the risk for mask re-spin. Based on a pre-characterized analog sub-circuit cell library, which contains not only active devices and passive components but also routing interconnects. This methodology systematically alleviates modeling inaccuracy at high frequencies due to the difference in the layout between device test structures and actual circuit implementation. By exploiting the modularity in analog circuits at the sub-circuit level, the proposed design platform achieves a balance between design flexibility and modeling accuracy compared. The macro modeling techniques the sub-circuit cells will be described along with measurement results from a characterization test chip.
Cataract Progression After Intravitreal Triamcinolone Injection

Purpose To assess cataract progression after intravitreal triamcinolone injection. Design Retrospective, interventional, case-control study. Methods Forty-two phakic eyes of 37 patients were injected one, two, or three times with intravitreal triamcinolone for various indications. Noninjected phakic fellow eyes served as the control. The mean follow-up time for single injection was 12 months, for multiple injections was 14 months, and for control group was 13 months. Lens status, best-corrected visual acuity, and refractive errors were recorded at baseline and at each follow-up examination. Results At the last follow-up, changes in posterior subcapsular cataract and refractive error from baseline were significantly different between single triamcinolone-injected eyes and the control group [0.7 ± 0.2 (mean ± SEM [arbitrary unit] vs 0.2 ± 0.1, P = .02; and −0.5 ± 0.1 diopter vs −0.2 ± 0.1 diopter, P = .01, respectively). For multiple-injected eyes and control eyes, change from baseline in corticonuclear cataract (1.1 ± 0.2 vs 0.2 ± 0.1), posterior subcapsular cataract (1.1 ± 0.2) and refractive error (−1.8 ± 0.4 diopters) were significantly different ( P P P P = .83) and in control group ( P = .19) but decreased after multiple injections ( P = .006). Eleven study eyes and two control group eyes underwent cataract extraction during study period. Corticonuclear and posterior subcapsular cataract progression significantly correlated with follow-up time ( P = .003 and P = .02, respectively) and number of injections ( P = .01 and P = .04, respectively). Conclusions Single intravitreal triamcinolone injection induces posterior subcapsular cataract development, whereas multiple injections result in all-layer cataract progression.
HEAVY ION PION PRODUCTION: SPECTRAL IRREGULARITIES

Abstract Data on π − π + ratios and on hills and valleys in spectra from heavy ion collisions are reviewed. Theoretical studies to handle Coulomb effects on pion spectra are examined. The possible role of strongly-bound pion Orbitals of nuclear size is discussed.
A case history in interactive problem-solving

MACSYMA [1], a computer program for algebraic manipulation, is used to solve, symbolically and exactly, a problem involving integration and the solution of an infinite set of linear equations. This is a tutorial in the use of MACSYMA, and illustrates some of the choices available to the interactive user which aid in solving a mathematical problem.
Imine-epoxide rearrangements in the formation of substituted piperidines. A stereoselective synthesis of (±) solenopsin-A.

Abstract The imine-epoxide rearrangement, followed by hydride reduction has been used to prepare substituted piperidine derivatives with control of stereochemistry. An application to the synthesis of (±) solenopsin A is reported.
SYNTHETIC STUDIES OF ANTITUMOR MACROLIDE LAULIMALIDE: ENANTIOSELECTIVE SYNTHESIS OF THE C3-C14 SEGMENT BY A CATALYTIC HETERO DIELS-ALDER STRATEGY.

The C3-C14 segment of the novel antitumor agent laulimalide has been constructed enantioselectively by utilizing a catalytic asymmetric hetero Diels-Alder reaction of benzyloxyacetaldehyde and Danishefsky's diene followed by Ferrier rearrangement and asymmetric conjugate reaction as the key steps.
Solar flare model atmospheres

Solar flare model atmospheres computed under the assumption of energetic equilibrium in the chromosphere are presented. The models use a static, one-dimensional plane parallel geometry and are designed within a physically self-consistent coronal loop. Assumed flare heating mechanisms include collisions from a flux of non-thermal electrons and x-ray heating of the chromosphere by the corona. The heating by energetic electrons accounts explicitly for variations of the ionized fraction with depth in the atmosphere. X-ray heating of the chromosphere by the corona incorporates a flare loop geometry by approximating distant portions of the loop with a series of point sources, while treating the loop leg closest to the chromospheric footpoint in the plane-parallel approximation. Coronal flare heating leads to increased heat conduction, chromospheric evaporation and subsequent changes in coronal pressure; these effects are included self-consistently in the models. Cooling in the chromosphere is computed in detail for the important optically thick HI, CaII and MgII transitions using the non-LTE prescription in the program MULTI. Hydrogen ionization rates from x-ray photo-ionization and collisional ionization by non-thermal electrons are included explicitly in the rate equations. The models are computed in the 'impulsive' and 'equilibrium' limits, and in a set of intermediate 'evolving' states. The impulsive atmospheres have the density distribution frozen in pre-flare configuration, while the equilibrium models assume the entire atmosphere is in hydrostatic and energetic equilibrium. The evolving atmospheres represent intermediate stages where hydrostatic equilibrium has been established in the chromosphere and corona, but the corona is not yet in energetic equilibrium with the flare heating source. Thus, for example, chromospheric evaporation is still in the process of occurring.
Synthesis of D-Erythroascorbic Acid

ABSTRACT D-Erythroascorbic acid (4) was synthesized from D-glucose in four steps. Compound (4) and L-ascorbic acid (5) were lost at approximately equal rates from aqueous solution at pH 7 in the presence and absence of added cupric ion.
Effect of crystal and beam tilt on simulated high-resolution TEM images of interfaces.

The effects of crystal and beam tilt on high-resolution transmission electron microscope (HRTEM) images of planar coherent interfaces were investigated by multislice image simulations. It was found that a beam tilt of 0.5 Bragg angle (θB) was sufficient to introduce detrimental artifacts into most images of interfaces in crystals only 1/8ξ000 thick, while crystal tilt had a much smaller effect even for crystals 1ξ000 thick. Effects produced in HRTEM images of interfaces by crystal and beam tilt included the introduction of additional periodicities and loss of compositional detail across a boundary, translation of a boundary from its actual position, and apparent mismatch of atomic planes across a perfectly coherent interface. These results indicate that alignment of the electron beam parallel to the optic axis is critical for reliable HRTEM imaging of interfaces in materials. Techniques for obtaining accurate alignment are also discussed. © 1992 Wiley-Liss, Inc.
LIGHT SCATTERING FROM EXOPLANET OCEANS AND ATMOSPHERES

Orbital variation in reflected starlight from exoplanets could eventually be used to detect surface oceans. Exoplanets with rough surfaces, or dominated by atmospheric Rayleigh scattering, should reach peak brightness in full phase, orbital longitude (OL) = 180°, whereas ocean planets with transparent atmospheres should reach peak brightness in crescent phase near OL = 30°. Application of Fresnel theory to a planet with no atmosphere covered by a calm ocean predicts a peak polarization fraction of 1 at OL = 74°; however, our model shows that clouds, wind-driven waves, aerosols, absorption, and Rayleigh scattering in the atmosphere and within the water column dilute the polarization fraction and shift the peak to other OLs. Observing at longer wavelengths reduces the obfuscation of the water polarization signature by Rayleigh scattering but does not mitigate the other effects. Planets with thick Rayleigh scattering atmospheres reach peak polarization near OL = 90°, but clouds and Lambertian surface scattering dilute and shift this peak to smaller OL. A shifted Rayleigh peak might be mistaken for a water signature unless data from multiple wavelength bands are available. Our calculations suggest that polarization alone may not positively identify the presence of an ocean under an Earth-like atmosphere; however, polarization adds another dimension which can be used, in combination with unpolarized orbital light curves and contrast ratios, to detect extrasolar oceans, atmospheric water aerosols, and water clouds. Additionally, the presence and direction of the polarization vector could be used to determine planet association with the star, and constrain orbit inclination.
Equation problem over central extensions of hyperbolic groups

The Equation problem in finitely presented groups asks if there exists an algorithm which determines in finite amount of time whether any given equation system has a solution or not. We show that the Equation Problem in central extensions of hyperbolic groups is solvable.
High-quantum-efficiency luminescence from a conducting polymer in solution: a novel polymer laser dye

A novel dye laser based on the soluble conducting polymers poly[2- methoxy, 5-(2' ethyl-hexyloxy)-p-phenylenevinylene], MEH-PPV, and [2,5-bis(5,6- dihydrocholestanoxy)-1,4-phenylene vinylene], DC-PPV, has been demonstrated. Laser action has been tested in a transverse cavity configuration where the conducting polymer laser was pumped by light pulses generated from the second harmonic radiation of a Q-switched Nd:YAG laser. The performance of MEH-PPV in solution as a laser dye was compared to that of Rhodamine 6G in solution under identical conditions. The results indicate that the luminescence quantum yield of MEH-PPV and DC-PPV lasers is comparable to that of Rhodamine 6G.© (1993) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
On tadpole improvement for staggered fermions

Abstract An explanation is proposed for the fact that Lepage—Mackenzie tadpole improvement does not work well for staggered fermions. The idea appears to work for all renormalization constants which appear in the staggered fermion self-energy. Wilson fermions are also discussed.
Advances in the treatment of chronic lymphocytic leukemia.

A dramatic change has taken place in therapy for chronic lymphocytic leukemia over the past 15 years. In 1990, available therapy produced complete responses in less than 5% of treated patients. This is in marked contrast to modern regimens, which can reliably produce complete responses in over 50% of patients. This remarkable improvement is completely attributable to the introduction of new active agents. These new agents include three purine analogues (pentostatin, fludarabine, and cladribine) and two monoclonal antibodies (rituximab and alemtuzumab). Novel combinations of these agents have emerged as effective new therapies for previously untreated and pretreated patients. Clinical studies indicate that such combinations can induce higher response rates—including complete responses—than single-agent therapy. Those patients who achieve a complete response have superior survival, compared with those who achieve only a partial response. Though not yet demonstrated in a prospective randomized trial, treatment approaches aimed at achieving high-quality responses may one day lead to an improvement in survival for patients with chronic lymphocytic leukemia and, ultimately, offer the hope of curative therapy in these patients.
Automatic continuity of homomorphisms and fixed points on metric compacta

We prove that arbitrary homomorphisms from one of the groups $$Homeo(2^\mathbb{N} ), Homeo(2^\mathbb{N} )^\mathbb{N} , Aut(\mathbb{Q}, < ), Homeo(\mathbb{R}) or Homeo(S^1 )$$ into a separable group are automatically continuous. This has consequences for the representations of these groups as discrete groups. For example, it follows, in combination with a result of V. G. Pestov, that any action of the discrete group Homeo+(ℝ) by homeomorphisms on a compact metric space has a fixed point.
DERMAL NEUROVASCULAR DYSFUNCTION IN TYPE 2 DIABETES

OBJECTIVE: To review evidence for a relationship between dermal neurovascular dysfunction and other components of the metabolic syndrome of type 2 diabetes. RESEARCH DESIGN AND METHODS: We review and present data supporting concepts relating dermal neurovascular function to prediabetes and the metabolic syndrome. Skin blood flow can be easily measured by laser Doppler techniques. RESULTS: Heat and gravity have been shown to have specific neural, nitrergic, and independent mediators to regulate skin blood flow. We describe data showing that this new tool identifies dermal neurovascular dysfunction in the majority of type 2 diabetic patients. The defect in skin vasodilation is detectable before the development of diabetes and is partially correctable with insulin sensitizers. This defect is associated with C-fiber dysfunction (i.e., the dermal neurovascular unit) and coexists with variables of the insulin resistance syndrome. The defect most likely results from an imbalance among the endogenous vasodilator compound nitric oxide, the vasodilator neuropeptides substance P and calcitonin gene-related peptide, and the vasoconstrictors angiotensin 11 and endothelin. Hypertension per se increases skin vasodilation and does not impair the responses to gravity, which is opposite to that of diabetes, suggesting that the effects of diabetes override and counteract those of hypertension. CONCLUSIONS: These observations suggest that dermal neurovascular function is largely regulated by peripheral C-fiber neurons and that dysregulation may be a component of the metabolic syndrome associated with type 2 diabetes.
New trialkylsilyl enol ether chemistry: α-N-tosylamination of triisopropylsilyl enol ethers

Abstract Triisopropylsilyl enol ethers reaet with (TsN)2Se to give α-N-tosylamino derivatives in modest to good yields. In the absence of 1,3-diaxial interactions the N-tosylamino group prefers an axial conformation. The axial N-tosylamino derivatives can be readily transformed into the azabicyclo[3.3.1]nonane skeleton, the core structure of a number of alkaloids.
Comparative cooperative game theory

Given two side-payment gamesv andw, both defined for the same finite player-setN, the following three welfare criteria are characterized in terms of the datav andw: (A) For everyy ∃ C(w) there existsx ∃ C(v) such thaty≤x; (A′) For everyx∃C(v) there existsyeC(w) such thaty≤x; and (B) There existyeC(w) andxeC(v) such thaty≤x. (HereC(v) denotes the core ofv.) Given two non-side-payment gamesv andw, sufficient conditions for the criteria (A′) and (B) are established, by observing that an ordinal convex game has a large core.
Black Holes Without Coordinates

These lectures describe how to study the geometry of some black holes without the use of coordinates.
Validation of a Model for a Two-Bladed Flexible Rotor System: Progress to Date

At the National Renewable Energy Laboratory, we tested a very flexible wind turbine. This machine, the Cannon Wind Eagle turbine, exhibited an ability to significantly reduce the rotor flap-wise bending moments through a unique combination of a flexible rotor and hub design. In parallel to this testing effort, we developed analytical models of this machine using our simulation codes. The goal of this work was to validate the analytical models of this machine by comparing analytical predictions to measured results from the real machine. We first describe briefly the simulation codes used in this study. We then describe the wind turbine we analyzed. We then describe analytical model validation progress for this flexible rotor and show preliminary validation results. Finally, we make conclusions and state our plans for future studies.
Diastereo‐ and Enantioselective Iridium‐Catalyzed Carbonyl Propargylation from the Alcohol or Aldehyde Oxidation Level: 1,3‐Enynes as Allenylmetal Equivalents

In the presence of SEGPHOS catalysts, the reaction proceeds generally with high anti-selectivity regardless whether alcohols or aldehydes are used.
A new method for the phosphorylation of alcohols and phenols

Abstract A method is described for the synthesis of phosphate triesters from a trialkyl phosphite, I2, and an alcohol or phenol. The method gives excellent yields under very mild conditions, and is compatible with a variety of functional groups.
Evidence for the Multiple Production of Mesons in a Single Nucleon-Nucleon Collision

Evidence has been obtained for the multiple production of mesons in a single nucleon-nucleon collision in a photographic emulsion exposed to the cosmic radiation at an altitude of 95,000 ft. The nuclear encounter in which the mesons were created was produced by a primary proton of 3\ifmmode\times\else\texttimes\fi{}${10}^{13}$ ev energy. Directly in line with the incident proton 7 particles of minimum ionization were emitted in a central core with an angular divergence of 0.003 radian. In addition 8 other minimum ionization particles were emitted in a wider diffuse cone of 0.13 radian angular divergence. Only one track had the appearance of a fragment which, however, could have been a proton of 10-Mev energy. Most of the particles in the central core had energies in excess of 250 Bev, while those in the diffuse cone were of much lower energies as determined by small angle scattering measurements. A pair of very small angular divergence was produced in the central core 4800 microns from the point of origin of the nuclear interaction. Assuming that the pair were produced by a gamma-ray from the decay of a neutral meson, a lower limit of 2\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}15}$ second was deduced for its mean life. Both the angular and the energy distribution of the emitted particles is in good agreement with the assumption that in the center-of-mass system the mesons are emitted in two distinct cones of angular width of about 30\ifmmode^\circ\else\textdegree\fi{} forward and backward with reference to the direction of the primary proton. The average multiplicity of 15 agrees with the recent calculation by Fermi, and according to his prediction about one-half of the particles could be made up of nucleon-antinucleon pairs.
Some Design Techniques for Fluid-Jet Amplifiers

The operation of the fluid-jet amplifier is described briefly. A performance criterion is developed for the amplifiers, and design techniques are presented which constrain the amplifier to exhibit the decision function. The techniques involve the superposition of a bias on the amplifier which alters its switching characteristics. In addition, a stability criterion for amplifier operation is developed and its uses are suggested. Some effects of internal geometry variations are also discussed.
Transcranial phase aberration correction using beam simulations and MR-ARFI

Purpose: Transcranial magnetic resonance-guided focused ultrasound surgery is a noninvasive technique for causing selective tissue necrosis. Variations in density, thickness, and shape of the skull cause aberrations in the location and shape of the focal zone. In this paper, the authors propose a hybrid simulation-MR-ARFI technique to achieve aberration correction for transcranial MR-guided focused ultrasound surgery. The technique uses ultrasound beam propagation simulations with MR Acoustic Radiation Force Imaging (MR-ARFI) to correct skull-caused phase aberrations. Methods: Skull-based numerical aberrations were obtained from a MR-guided focused ultrasound patient treatment and were added to all elements of the InSightec conformal bone focused ultrasound surgery transducer during transmission. In the first experiment, the 1024 aberrations derived from a human skull were condensed into 16 aberrations by averaging over the transducer area of 64 elements. In the second experiment, all 1024 aberrations were applied to the transducer. The aberrated MR-ARFI images were used in the hybrid simulation-MR-ARFI technique to find 16 estimated aberrations. These estimated aberrations were subtracted from the original aberrations to result in the corrected images. Each aberration experiment (16-aberration and 1024-aberration) was repeated three times. Results: The corrected MR-ARFI image was compared to the aberrated image and the ideal image (imagemore » with zero aberrations) for each experiment. The hybrid simulation-MR-ARFI technique resulted in an average increase in focal MR-ARFI phase of 44% for the 16-aberration case and 52% for the 1024-aberration case, and recovered 83% and 39% of the ideal MR-ARFI phase for the 16-aberrations and 1024-aberration case, respectively. Conclusions: Using one MR-ARFI image and noa priori information about the applied phase aberrations, the hybrid simulation-MR-ARFI technique improved the maximum MR-ARFI phase of the beam's focus.« less
Patterns of productivity growth in South Korean manufacturing industries, 1963–1979

Abstract In this paper we estimate sources of labor productivity growth in 25 Korean manufacturing industries between 1963 and 1979. We find that less than half of the 11 percent annual increase in overall manufacturing labor productivity can be attributed to capital deepening, and that the importance of this factor and total factor productivity advance varied sharply across industries. Heavy industries accumulated capital per worker at a faster pace, and realized total factor productivity growth at a much slower rate, than others did. This contrast may be related to the extensive capital subsidies provided to the former as part of an import-substitution program. Also, the rapid total factor productivity growth in labor-intensive manufacturing industries was accompanied by rapid growth in average firm size, supporting the argument that the shift from craft to modern production techniques has been a major source of productivity growth.
Abstracting dependencies between software configuration items

This article studies an abstract model of dependencies between software configuration items based on a theory of concurrent computation over a class of Petri nets called production nets. A general theory of build optimizations and their correctness is developed based on a form of abstract interpretation called a build abstraction; these are created during a build and are used to optimize subsequent builds. Various examples of such optimizations are discussed. The theory is used to show how properties can be characterized and proved, and how optimizations can be composed and compared.
Obamacare's (3) Day(s) in Court

Before the oral arguments in late March, the vast majority of legal scholars felt confident that the Supreme Court of the United States would uphold the individual mandate against the constitutional challenge that 26 states have levied against it. Since the oral arguments, that confidence has been severely shaken. This article asks why legal scholars were so confident before the argument and what has made us so concerned since the argument. The article posits that certain fundamental characteristics of health insurance, particularly its unusual role in steering health-care consumption decisions, which distinguishes health insurance from standard kinds of indemnity insurance, should make the constitutional question easy, but the Obama Administration's legal team was understandably hesitant to highlight those unique characteristics in its arguments. Because the Supreme Court justices seemed not to understand the uniqueness of health insurance without the government's help and because the justices seemed unusually willing to adopt a new constitutional constraint in this case, the individual mandate appears to be in far greater jeopardy than we legal scholars anticipated.
Compressible Seal Flow Analysis Using the Finite Element Method with Galerkin Solution Technique

High pressure gas sealing involves not only balancing the viscous force with the pressure gradient force but also accounting for fluid inertia—especially for choked flow. The conventional finite element method which uses a Rayleigh-Ritz solution technique is not convenient for nonlinear problems. For these problems, a finite element method with a Galerkin solution technique (FEMGST) was formulated. One example, a three-dimensional axisymmetric flow formulation, has nonlinearities due to compressibility, area expansion, and convective inertia. Solutions agree with classical results in the limited cases. The development of the choked flow velocity profile is shown. Presented as an American Society of Lubrication Engineers paper at the ASLE/ASME Lubrication Conference held in Montreal, Canada, October 11–10, 1974
Robust nanopatterning by laser-induced dewetting of metal nanofilms

We have observed nanopattern formation with robust and controllable spatial ordering by laser-induced dewetting in nanoscopic metal films. Pattern evolution in Co film of thickness 1≤h≤8 nm on SiO(2) was achieved under multiple pulse irradiation using a 9 ns pulse laser. Dewetting leads to the formation of cellular patterns which evolve into polygons that eventually break up into nanoparticles with unimodal size distribution and short range ordering in nearest neighbour spacing R. Spatial ordering was attributed to a hydrodynamic thin film instability and resulted in a predictable variation of R and particle diameter D with h. The length scales R and D were found to be independent of the laser energy. These results suggest that spatially ordered metal nanoparticles can be robustly assembled by laser-induced dewetting.
Work in progress — Collaborative and reflective learning in engineering programs

Learning objects (LOs) were proposed as a way to build reusable chunks of educational content. But in spite of considerable effort by various groups, the approach has had relatively little impact on education. We argue that this is because of a fundamental weakness in the way LOs have been conceived of. We show how the problem can be addressed by borrowing key ideas from object-oriented (OO) programming. We show that the resulting approach will not only help students in learning particular concepts but also help develop their reflective and team-working skills. The approach is also consistent with the ideas of the how people learn (HPL) framework.
Fuzzy ellipsoidal shell clustering algorithm and detection of elliptical shapes

Fuzzyc-Efflpsoidal Shell (FCES) algorithm that utilizes hyper-ellipsoidal-shells as cluster prototypes is proposed. FCES is a generalization of the Fuzzy Shell Clustering (FSC) algorithm. The generalization is achieved by allowing the distances measured through a norm inducing matrix that is symmetric positive definite. In case offixed known norms the extension of FcS to FCS is straightforward. Two different strategies are recommended when the norm is unknown. The first strategy considers use of non-linear least-squared fit approach with fuzzy memberships as weights. The second approach considers norm inducing matrix as a variable of optimization thus making FCES an adaptive norm type algorithm. An adaptive norm theorem is presented. The results of first approach is used to detect ellipses having unequal sizes and orientations in two-dimensional data-sets. Non-linear equations of the FCES algorithm are more complex than those of the FSC algorithm. Numerical issues related to both the FCES algorithm and the FSC algorithm are discussed.© (1991) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Gaseous jet in supersonic crossflow

We describe an analytical/numerical model representing the deflection and mixing of a single gaseous jet in supersonic crossflow. The jet cross section is modeled in terms of a compressible vortex pair that results from viscous and impulsive forces acting at the periphery of the jet. The behavior of the vortex pair is then combined with mass and momentum balances along the axis of the jet to form a model that describes the trajectory and mixing of the injected fluid
On the role of conical intersections and their local topography in the photodissociation of the 1-hydroxyethyl radical

Abstract The role of conical intersections in the photodissociation of the 1-hydroxyethyl radical is investigated. Two local minima on the 1 2 A–2 2 A seam of the conical intersection, which correspond to significant stretching of either the O–H or the nonmethyl C–H bond are located, as is an energy minimized intersection on the 2 2 A–3 2 A seam. The local topography for these conical intersections is determined from the average energy gradient, energy difference gradient and interstate coupling gradient and used to discuss the mechanism of photodissociation. The results are compared with a theoretical study of the hydroxymethyl radical, and are used to explain recent REMPI and photofragment yield spectra. The absence of a REMPI spectrum for the 2 2 A state, nominally the 3s Rydberg state, is attributed to a 1 2 A–2 2 A conical intersection. Time-of-flight spectra in the region of the 2 2 A state are discussed, as are spectra in the region of the 3 2 A, a 3p Rydberg, state.
Betatron ping tune measurement system for the IUCF cooler synchrotron/storage ring

Abstract A system has been developed for nearly real-time measurement of the coherent betatron fractional tune, ΔQ , in the IUCF cooler synchrotron/storage ring. This system measures the horizontal and vertical beam position on a turn-by-turn basis for beam currents in the range from 1 mA. A fast Fourier transform of this position data is performed by a PC-based DSP (Digital Signal Processor) module at a rate of 10 measurements per second yielding the betatron fractional tune. This tune information has been used to modify ramp parameters in order to minimize the tune shift. This paper describes the ping tune system's overall design principles, details of the various electronics systems, and compares the theoretical performance with the measured performance.
SUGRA Grand Unification, LHC and dark matter

A brief review is given of recent developments related to the Higgs signal and its implications for supersymmetry in the supergravity grand unification framework. The Higgs data indicates that the allowed parameter space largely lies on Focal Curves and Focal Surfaces of the Hyperbolic Branch of radiative breaking of the electroweak symmetry where TeV size scalars naturally arise. The high mass of the Higgs leads to a more precise prediction for the allowed range of the spin independent neutralino–proton cross–section which is encouraging for the detection of dark matter in future experiments with greater sensitivity. Also discussed is the status of grand unification and a natural solution to breaking the GUT group at one scale and resolving the doublet–triplet problem. It is shown that the cosmic coincidence can be compatible within a supersymmetric framework in a muticomponent dark matter picture with one component charged under B – L while the other component is the conventional supersymmetric dark matter candidate, the neutralino.
Evolution of Hele-Shaw Interface for Small Surface Tension

We consider the time-evolving displacement of a viscous fluid by another fluid of negligible viscosity in a Hele-Shaw cell, either in a channel or a radial geometry, for idealized boundary conditions developed by McLean & Saffman. The interfacial evolution is conveniently described by a time-dependent conformal map z($\zeta $, t) that maps a unit circle (or a semicircle) in the $\zeta $ plane into the viscous fluid flow region in the physical z-plane. Our paper is concerned with the singularities of the analytically continued z($\zeta $, t) in $|\zeta|$ > 1, which, on approaching $|\zeta|$ = 1, correspond to localized distortions of the actual interface. For zero surface tension, we extend earlier results to show that for any initial condition, each singularity, initially present in $|\zeta|$ > 1, continually approaches $|\zeta|$ = 1, the boundary of the physical domain, without any change in the singularity form. However, depending on the singularity type, it may or may not impinge on $|\zeta|$ = 1 in finite time. Under some assumptions, we give analytical evidence to suggest that the ill-posed initial value problem in the physical domain $|\zeta|\leq $ 1 can be imbedded in a well-posed problem in $|\zeta|\geq $ 1. We present a numerical scheme to calculate such solutions. For each initial singularity of a certain type, which in the absence of surface tension would have merely moved to a new location $\zeta \_{\text{s}}$ (t) at time t from an initial $\zeta \_{\text{s}}$(0), we find an instantaneous transformation of the singularity structure for non-zero surface tension $\beta $; however, for 0 < $\beta \ll $ 1, surface tension effects are limited to a small `inner' neighbourhood of $\zeta \_{\text{s}}$(t) when t $\ll \beta ^{-1}$. Outside the inner region, but for $|\zeta -\zeta \_{\text{s}}$(t)$|\ll $ 1, the singular behaviour of the zero surface tension solution z$\_{0}$ is reflected in z($\zeta $, t). On the other hand, for each initial zero of z$\_{\zeta}$, which for $\beta $ = 0 remains a zero of z$\_{0\zeta}$ at a location $\zeta \_{0}$(t) that is generally different from $\zeta \_{0}$(0), surface tension spawns new singularities that move away from $\zeta \_{0}$(t) and approach the physical domain $|\zeta|$ = 1. We find that even for 0 < $\beta \ll $ 1, it is possible for z - z$\_{0}$ = O(1) or larger in some neighbourhood where z$\_{0\zeta}$ is neither singular nor zero. Our findings imply that for a small enough $\beta $, the evolution of a Hele-Shaw interface is very sensitive to prescribed initial conditions in the physical domain.
Supergravity solutions for localized intersections of branes

We construct an explicit supergravity solution for a configuration of localized D4-brane ending on a D6-brane, restricted to the near horizon region of the latter. We generate this solution by dimensionally reducing the supergravity solution for a flat M5-brane in R1,7 × C2/ZN with the M5-brane partially embedded in C2/ZN. We describe the general class of localized intersections and overlaps whose supergravity solutions are constructible in this way.
Radiative torque alignment: essential physical processes

We study the physical processes that affect the alignment of grains subject to radiative torques (RATs). To describe the action of RATs, we use the analytical model (AMO) of RATs introduced in our previous paper. We focus our discussion on the alignment by anisotropic radiation flux with respect to the magnetic field, which defines the axis of grain Larmor precession. Such an alignment does not invoke paramagnetic dissipation (i.e. the Davis-Greenstein mechanism), but, nevertheless, grains tend to be aligned with long axes perpendicular to the magnetic field. When we account for thermal fluctuations within grains, we show that for grains that are characterized by a triaxial ellipsoid of inertia, the zero-J attractor point obtained in our earlier study develops into a low-J attractor point. The value of angular momentum at the low-J attractor point is of the order of the thermal angular momentum corresponding to the grain temperature. We show that, for situations when the direction of radiative flux is nearly perpendicular to a magnetic field, the alignment of grains with long axes parallel to the magnetic field (i.e. 'wrong alignment') reported in our previous paper, disappears in the presence of thermal fluctuations. Thus, all grains are aligned with their long axes perpendicular to the magnetic field. We study the effects of stochastic gaseous bombardment and show that gaseous bombardment can drive grains from low-J to high-J attractor points in cases when high-J attractor points are present. As the alignment of grain axes with respect to angular momentum is higher for higher values of J, counter-intuitively, gaseous bombardment can increase the degree of grain alignment with respect to the magnetic field. We also study the effects of torques induced by H 2 formation and show that they can change the value of angular momentum at high-J attractor points, but marginally affect the value of angular momentum at low-J attractor points. We compare the AMO results with those obtained using the direct numerical calculations of RATs acting upon irregular grains and we validate the use of the AMO for realistic situations of RAT alignment.
Diastereoselective oxidation of substituted thietanes and stereoselective oxidation of their sulfoxides

Abstract Oxidation of substituted thietanes 1a, b, and 6 with m-chloroperoxybenzoic acid preferentially gives the corresponding cis-sulfoxides with modest diastereoselectivity. Selective oxidation of the trans over the cis diastereomeric pairs of sulfoxides 2a, 3a; 2b, 3b; 7, 8 occurs with moderate selectivity with m-chloroperoxybenzoic acid. The basis for these selectivities is hydrogen bonding between the 3-substituent and the peracid.
Kohn-Luttinger effect in nested Fermion liquids

We study the Kohn-Luttinger effect in a two-dimensional (2D) nested fermion liquid with a repulsive interaction via the renormalization group method and identify the resulting order parameter symmetry. Using the band structure of the 2D Hubbard model close to half-filling as a prototype, we construct an effective low-energy theory. We use multidimensional bosonization to incorporate the zero-sound channel and find marginal Fermi liquid behavior in the absence of any instability. We show an analog of the Landau theorem in nested fermion liquids, which serves as the criterion of the BCS instability. Including repulsive or antiferromagnetic exchange interactions in the low-energy theory, we show that the ${\mathrm{d}}_{{\mathrm{x}}^{2}\mathrm{\ensuremath{-}}{\mathrm{y}}^{2}}$-wave BCS channel is renormalized to be the most attractive. Below half-filling, when the nesting is not perfect, there is competition between the spin-density-wave (SDW) and the BCS channels; when the SDW coupling is small enough, there occurs a ${\mathrm{d}}_{{\mathrm{x}}^{2}\mathrm{\ensuremath{-}}{\mathrm{y}}^{2}}$-wave superconducting instability at sufficiently low temperatures.