cssi/SciSciGPT-SciSciNet huggingface dataset:
The formation and transformation of phosphorus–carbon bonds in living organisms

This review discusses recent work on biogenic organophosphorus compounds, with particular emphasis on mechanisms by which phosphorus-carbon bonds may be formed or broken and their relationship to corresponding mechanisms in the rapidly developping area of bio-organometalloidal chemistry
X-Ray and Radio Interactions in the Cores of Cooling Flow Clusters

We present high-resolution ROSAT X-ray and radio observations of three cooling flow clusters containing steep-spectrum radio sources at their cores. All three systems exhibit strong signs of interaction between the radio plasma and the hot intracluster medium. Two clusters, A133 and A2626, show enhanced X-ray emission spatially coincident with the radio source, whereas the third cluster, A2052, exhibits a large region of X-ray excess surrounding much of the radio source. Using three-dimensional numerical simulations, we show that a perturbed jet propagating through a cooling flow atmosphere can give rise to amorphous radio morphologies, particularly in the case where the jet was "turned off" and allowed to age passively. In addition, the simulated X-ray surface brightness produced both excesses and deficits as seen observationally.
Virulence of papillary endometrial carcinoma

While uterine papillary serous carcinoma (UPSC) has been well described as a virulent subtype of endometrial adenocarcinoma (AC), with behavior similar to that of papillary serous ovarian carcinoma, the papillary endometrial (PE) variant has not been well characterized. We studied 117 patients with endometrial carcinoma identified by our tumor registry, pathology files, and practice records from March 1981 to February 1989: 76 with AC, 26 with PE, and 15 with UPSC. Age and demographic data were similar for all three groups. All of the AC patients, 84% of PE patients, and 87% of UPSC patients had early-stage disease by clinical exam; however, 10% of AC patients, 23% of PE patients, and 87% of UPSC patients had extrauterine disease at surgery (P < 0.05). Deep myometrial invasion occurred in 29% of AC patients, 36% of PE patients, and 60% of UPSC patients (P < 0.05). Comparative analysis of the PE and UPSC groups revealed more marked nuclear anaplasia (P < 0.05) and more frequent vascular space involvement (nonsignificant) in the UPSC group. At 3 years, 75% of the AC group was alive without disease. In contrast, the median progression-free interval for the PE group was 33 months, and for the UPSC group, 9 months (P < 0.05). These data suggest a transition of increasing virulence corresponding with increasing papillary features, from AC to PE to UPSC. The papillary feature may be a new, significant risk factor in endometrial carcinoma.
Quantitative Homotopy Theory in Topological Data Analysis

This paper lays the foundations of an approach to applying Gromov’s ideas on quantitative topology to topological data analysis. We introduce the “contiguity complex”, a simplicial complex of maps between simplicial complexes defined in terms of the combinatorial notion of contiguity. We generalize the Simplicial Approximation Theorem to show that the contiguity complex approximates the homotopy type of the mapping space as we subdivide the domain. We describe algorithms for approximating the rate of growth of the components of the contiguity complex under subdivision of the domain; this procedure allows us to computationally distinguish spaces with isomorphic homology but different homotopy types.
Condensation of hard spheres under gravity

Abstract Starting from the Enskog equation of hard spheres of mass m and diameter D under the gravity g, we first derive the exact equation of motion for the equilibrium density profile at a temperature T and examine its solutions via the gradient expansion. The solutions exist only when βμ⩽μ0, where μ is the dimensionless initial layer thickness and β=mgD/T, and the precise value of the upper bound μ0 depends on the underlying packing. When this inequality breaks down, a fraction of particles condenses from the bottom toward the surface.
STRUCTURE AND BONDING IN ALKALI-METAL-DOPED C60

IT has been shown recently that MxC60 (M = alkali metal) is metallic at 300 K for some M and x (ref. 1) and superconducts below 18 K for M = potassium2. These observations give further impetus to studies of the molecular3 and solid-state4 properties of fullerenes. Here we report on X-ray diffraction studies of the structure and bonding in alkali-metal-doped solid C60 (fullerite). Powder diffraction data obtained from equilibrium compositions of C60 doped to saturation with K or Cs show that the face-centred cubic lattice of pure C60 (refs 5–7) transforms to body-centred cubic at these doping levels, with a saturation composition close to M6C60. The rotational disorder of the fullerene molecules in pure C60 at 300 K is absent in the fully doped compounds.
AN EXPEDITIOUS SYNTHESIS OF ESTRONE

Abstract The Tris annelating agent, 6-(2-methyl-6-pyridyl-hex-l-ene-3-one), has been synthesized in four steps from the readily available 2,6-lutidine. To this 12-carbon ensemble is added, in a Michael fashion, 2-methycyclopentane-1,3-dione. The prochiral pyridyltrione, so produced, can be cyclized to afford 4-(2-α-picolylethyl)-hydrind-4-ene-3,7-dione (I). Using conventional acidic catalysis, compound I is obtained as the racemate. However, under the influence of L-phenylalanine, an 86% enrichment (i.e. 93% 13S; 7% 13R) of the desired enantiomer is realized. The key reaction in the steroid synthesis involves Birch reduction of the pyridine ring followed by hydrolytic ring opening, recyclization via the aldol route, deketalization and vinylogous aldol cyclization.
Stable String Operations Are Trivial

We show that in closed string topology and in open-closed string topology with one D-brane, higher genus stable string operations are trivial. This is a consequence of Harer's stability theorem and related stability results on the homology of mapping class groups of surfaces with boundaries. In fact, this vanishing result is a special case of a general result that applies to all homological conformal field theories with the property that in the associated topological quantum field theories, the string operations associated to genus 1 cobordisms with one or two boundaries vanish. In closed string topology, the base manifold can be either finite-dimensional, or infinite-dimensional with finite-dimensional cohomology for its based loop space. The above vanishing result is based on the triviality of string operations associated to the homology classes of mapping class groups that are in the image of stabilizing maps.
Security Patch Management

Abstract The goals behind implementing a security patch management process cover many elements of a sound security program. Security patch management positions the security management process within the larger problem space: vulnerability management. It improves the way the organization is protected from current threats and copes with growing threats. Another goal is to improve the dissemination of information to the user community, the people responsible for the systems, and the people responsible for ensuring that the affected systems are patched properly. It formalizes record keeping, in the form of tracking and reporting. It introduces a discipline: an automated discipline that can be easily adapted once the process is in place. It also can allow a company to deal with security vulnerabilities as they are released with a small amount of resources, and prior- itize effectively. It improves accountability within the organization for the roles directly responsible for security and systems. With this in m...
Cu-Catalyzed Asymmetric Conjugate Additions of Dialkyl- and Diarylzinc Reagents to Acyclic β-Silyl-α,β-unsaturated Ketones. Synthesis of Allylsilanes in High Diastereo- and Enantiomeric Purity

A readily available and simple (MW = 444.5 g/mol) valine-based chiral phosphine is used to promote highly efficient catalytic asymmetric conjugate additions of dialkyl- and diarylzinc reagents to acyclic β-silyl-α,β-unsaturated ketones. The catalytic asymmetric protocol allows access to versatile allylsilanes that bear a trisubstituted olefin in high diastereo- and enantiomeric purity.
Host-parasite relationships of Schistosoma mansoni.

Repeated exposures of Australorbis glabratus of Venezuelan origin to miracidia of Schistosoma mansoni indicate that all members of a given group of snails eventually will become infected. It is concluded that resistance to infection with miracidia of Schistosoma mansoni is not developed by these snails. Studies on the infectivity of Schistosoma mansoni confirm previous reports on the susceptibility of the albino mouse and confirm the observation that gradual adaptation of human strains of Schistosoma mansoni to mice is unnecessary in order to infect them. Mice infected with female Schistosoma mansoni are not protected against subsequent exposures to cercariae of both sexes. A vaccine made from cercariae does not protect mice against a challenging dose of cercariae. When mice are exposed to cercariae of Schistosoma mansoni more than three times and if the intervals between exposures range from a week to a month, immunity develops that manifests itself by causing cessation of development of new larval worms. “Immunity” is used in the sense of “resistance” and refers to immunity acquired from a challenging dose and not to that derived from the already acquired infection. This does not eradicate the disease and the animal dies as rapidly as from a single infection. Re-exposure of two highly susceptible types of animals, the mouse and the hamster, and of two highly resistant types of animals, the guinea pig and the albino rat, after development of mature worms from an initial infection has taken place, results in the recovery of worms after the second exposure in the same percentage as after initial infections. Thus, no immunity is developed. Splenectomy in mice and rats does not affect the course of initial infections or reinfections. Failure of guinea pigs and rats to die after massive initial infection and reinfection evidently is caused by natural resistance, which produces destruction of eggs in the tissues and worms in the vessels. Of the two animals, the rat is more effective in this regard than the guinea pig. The mouse and the hamster lack this mechanism. Multiple re-exposures in guinea pigs and rats produce no indication of immunity but the process of destruction of eggs and worms continues throughout the life of the animals. This process saves their lives but it is not a reflection of acquired immunity.
Mechanical behavior of 18 Ni 200 grade maraging steel at cryogenic temperatures

A comprehensive study was conducted to characterize the mechanical behavior of 18 Ni 200 grade maraging steel for cryogenic applications in the National Transonic Facility. Tensile, fatigue, impact, and fracture toughness properties were determined at room and cryogenic temperatures. Experimental variables included product form, specimen orientation, and variation in metallurgical condition accomplished with a grain refining heat treatment. Room temperature tensile yield strength was approximately 200 ksi, while the yield strength at -275 F was approximately 260 ksi. Charpy V-notch energy absorption values and fracture toughness values of 18 Ni steel were found to be dependent on temperature, product form, orientation, and metallurgical condition. Fracture toughness values ranged from 80 to 113 ksi-sq rt in. at room temperature and from 67 to 90 ksi-sq rt in. at -275 F. The results of this study indicate that 18 Ni 200 grade maraging steel exceeds the strength criterion of 150 ksi minimum yield strength for use in cryogenic wind tunnel models but is marginal with respect to the 85 ksi sq rt in fracture toughness criterion at -275 F.
An Artificial Neural Network Based Approach for Identification of Native Protein Structures Using an Extended Forcefield

Current protein force fields like the ones seen in CHARMM or Xplor-NIH have many terms that include bonded and non-bonded terms. Yet the force fields do not take into account the use of hydrogen bonds which are important for secondary structure creation and stabilization of proteins. SCOPE is an open-source program that generates proteins from rotamer space. It then creates a force field that uses only non-bonded and hydrogen bond energy terms to create a profile for a given protein. The profiles can then be used in an artificial neural network to create a linear model which is funneled to the true protein conformation.
Causes and effects of chaos

Abstract Most nonlinear dynamics and chaos literature is written either for readers of popular science magazines or for advanced mathematicians. This paper gives a broad introduction to this interesting and rapidly growing field at a level that is between the two. The graphical and analytical tools used in the literature are explained, a brief outline of the current theory is given, and that theory is illustrated with several examples: an electronic circuit, a chemical reaction and a system of satellites in the solar system.
Click chemistry generates privileged CH hydrogen-bonding triazoles: the latest addition to anion supramolecular chemistry

The supramolecular chemistry of anions provides a means to sense and manipulate anions in their many chemical and biological roles. For this purpose, Click chemistry facilitated the synthetic creation of new receptors and thus, an opportunity to aid in the recent re-examination of CH⋯anion hydrogen bonding. This tutorial review will focus on the privileged C–H hydrogen bond donor of the 1,2,3-triazole ring systems as elucidated from anion-binding studies with macrocyclic triazolophanes and other receptors. Triazolophanes are shape-persistent and planar macrocycles that direct four triazole and four phenylene CH groups into a 3.7 A cavity. They display strong (log K(Cl−) = 7), size-dependent halide binding (Cl− > Br− ≫ F− ≫ I−) and a rich set of binding equilibria. For instance, the too large iodide (4.4 A) can be sandwiched between two pyridyl-based triazolophanes with extreme positive cooperativity. Computational studies verify the triazole's hydrogen bond strength indicating it approaches the traditional NH donors from pyrrole. These examples, those of transport, sensing (e.g., ion-selective electrodes), templation, and versatile synthesis herald the use of triazoles in anion-receptor chemistry.
Closed-Loop Dynamic Stall Control Using a Plasma Actuator

A closed-loop plasma-actuated control scheme that relies on the ability to detect incipient flow separation is presented. It is based on the heightened receptivity of the boundary layer to disturbances at the onset of flow separation. A plasma actuator introduces periodic disturbances into the flow at a low-powered “sense state”. A pressure sensor measures the resulting pressure fluctuations close to the leading edge. When the sensed pressure fluctuations exceed a predetermined threshold level, the plasma actuator is switched to a high-powered “control state” that is designed to reattach the flow. The method provides not only a precursor for flow separation but also an indicator of when conditions exist where active flow reattachment is no longer needed. This is demonstrated on a periodically oscillating airfoil that is pitched into “light” and “deep” dynamic stall. The performance of the closed-loop scheme is evaluated by comparing the aerodynamic loading parameters to the baseline and open-loop unsteady...
The laser interferometer gravitational-wave observatory scientific data archive

Abstract LIGO – The Laser Interferometer Gravitational-Wave Observatory – is one of several large projects being undertaken in the United States, Europe and Japan to detect gravitational radiation. The novelty and precision of these instruments is such that large volumes of data will be generated in an attempt to find a small number of weak signals, which can be identified only as subtle changes in the instrument output over time. In this paper, I discuss how the nature of the LIGO experiment determines the size of the data archive that will be produced, how the nature of the analyses that must be used to search the LIGO data for signals determines the anticipated access patterns on the archive, and how the LIGO data analysis system is designed to cope with the problems of LIGO data analysis.
Microstructure control of an oxide superconductor by a hybridization process through grinding

Abstract A synthetic process for elaborating a nanocomposite of Ba 2 YCu 3 O 7− y superconductor and silver was examined. Hybridization through grinding promoted the uniform dispersion of ultrafine silver particles (of the order of 10 nm diameter) in the Ba 2 YCu 3 O 7− y matrix. The sintering process of the nanocomposite by hot isostatic pressing (HIP) suppressed undesirable grain growth of silver to the order of 100-300 nm in the sintered material. Enhancement of both superconducting transport current and magnetic flux pinning properties was promoted by the control of the post-annealing conditions of the HIPed material.
Critical Metallicity and Fine-Structure Emission of Primordial Gas Enriched by the First Stars

The influence of the first stars on the formation of second-generation objects at high redshift may be determined, in part, by their metal enrichment of surrounding gas. At a critical metallicity, Zcrit, primordial gas cools more efficiently by fine-structure lines of [C II] (157.74 μm), [O I] (63.18 μm, 145.5 μm), [Si II] (34.8 μm), and [Fe II] (25.99 μm, 35.35 μm) than by H I or H2 emission. This cooling may alter the process of fragmentation into smaller units. We study the time-dependent cooling of primordial gas enriched by heavy elements from early massive stars, particularly O, Si, and Fe. We define Zcrit as the point when the total cooling rate by metals plus H2 equals the adiabatic compressional heating. We explore two metallicity scenarios: (1) a single metallicity for all heavy elements and (2) individual metallicities (ZC, ZO, ZSi, and ZFe) from theoretical supernova yields. For dense gas (n ≥ 103 cm-3) with metals in relative solar abundances, fragmentation occurs at Zcrit ≈ 10-3.5 Z☉. However, for lower density gas (n = 1-100 cm-3), particularly in halos enriched in Si, O, and Fe, we find Zcrit ≈ 0.1%-1% Z☉. The critical metallicity approaches a minimum value at high n set by efficient LTE cooling, with thermalized level populations of fine-structure states and H2 rotational states (J = 2 and J = 3). Primordial clouds of 108 M☉ at 200 K are detectable in redshifted fine-structure lines, with far-infrared fluxes between 10-22 and 10-21 W m-2. For metallicities ZO ≈ 10-3 and molecular fractions f ≈ 10-3, the fine-structure emission lines of [O I], [Si II], and [Fe II] could be 102-103 times stronger than the H2 rotational lines at 28.22 μm (J = 2 → 0) and 17.03 μm (J = 3 → 1).
Frequency-domain equalization for continuous phase modulation

Single-carrier frequency-domain equalization (SC-FDE) is proposed for continuous phase modulation (CPM). Two different discrete representations of the CPM signal are obtained. One is an orthogonal representation obtained from the Gram-Schmidt orthonormalization procedure, and the other is obtained from Laurent's decomposition for binary CPM. The methodology for maintaining phase continuity with a cyclic guard interval is presented. Various optimal and suboptimal reduced-complexity approaches are suggested for SC-FDE of CPM signals. General full- and partial-response CPM waveforms, and specific examples of minimum-shift keying (MSK) and Gaussian MSK (GMSK) with BT=0.3 are investigated. Simulation results show that SC-FDE for CPM is an effective approach for CPM on channels having long impulse responses.
The Origin and Distribution of Diffuse Hot Gas in the Spiral Galaxy NGC 3184

Deep Chandra exposures reveal the presence of diffuse X-ray emission with a luminosity of 1.3 × 1039 ergs s-1 from the spiral galaxy NGC 3184. This appears to be truly diffuse thermal emission distinct from the low-luminosity emission from low-mass X-ray binaries (LMXBs). While the unresolved emission from older LMXBs is more uniformly distributed across the galaxy, the diffuse X-ray emission is concentrated in areas of younger stellar populations and star-forming regions. The surface brightness of the diffuse emission over the spiral arms is 5 times greater than in off-arm regions, and 8 times brighter in H II regions than in non–H II regions. Spectral fits to the diffuse thermal emission are consistent with a low-temperature component, T ~ 1.5 × 106 K, plus a higher temperature component, T ~ 5 × 106 K.
A reactivity umpolung route to cyclic homoenolate aldol products via α-alkoxyorganocuprate conjugate additions

Abstract Substituted α-alkoxyorganocuprate reagents readily undergo conjugate addition reactions with cyclic enones to provide homoaldol products.
Zitterbewegung of a photon

Abstract A single photon, satisfying a relativistic Schrodinger-like equation, has a velocity operator that undergoes oscillations in a direction orthogonal to its momentum. This Zitterbewegung has a spatial amplitude equal to the classical wavelength. The spin of the photon is the orbital angular momentum due to the Zitterbewegung.
Two Dimensional Topology of Large Scale Structure in the Las Campanas Redshift Survey

We have measured the topology (genus) of the density distribution of large-scale structure observed in the Las Campanas Redshift Survey (LCRS). The LCRS is complete to magnitude 17.5 and contains nearly 24,000 galaxies with median redshift of 30,000 km s-1. The large volume and large number of galaxies permit sampling of nearly 100 independent structures with which to compute the genus topology, a vast improvement over previous studies. We find that the genus is consistent with a random-phase Gaussian distribution of initial density fluctuations, as would be produced naturally in inflationary models. When we combine these results with the genus measurements of the COBE microwave background fluctuations, we find that two orthogonal projections of the three-dimensional distribution of initial density fluctuations are consistent with Gaussian random-phase behavior, in agreement with standard inflationary models. Particular attention is given to statistical significance of the genus test.
Experimental evidence of low frequency current drive in the Phaedrus-T tokamak

Summary form only given. The first experimental evidence of low frequency current drive in a tokamak has been observed on the Phaedrus-T tokamak (R/sub major/=0.92 m, r/sub minor/=0.255 m, B/sub T//spl ap/0.6-1 T, I/sub p/<100 kA, n/sub e0/=0.2-1.5/spl times/10/sup 19/ m/sup -3/). Low frequency current drive utilizes waves with frequencies below the ion cyclotron frequency to inject momentum to electrons to drive a toroidal current, and is often referred to as Alfven wave current drive (AWCD). Like other noninductive current drive techniques, AWCD would allow fusion tokamak reactors to operate as steady state devices. AWCD would also allow tailoring of the energy and current density profiles. Properly modified profiles would make the plasma less susceptible to instabilities. The presence of noninductive current is inferred from the behavior of the plasma loop voltage measured at the edge of the plasma The loop voltage can be roughly related to the sum of the ohmic dissipation, product of plasma current and resistance, and the time rate of change in the stored magnetic energy of the plasma during a plasma discharge, the plasma current is kept constant through automatic feedback control and is produced by pulsed magnetic induction. Therefore, the loop voltage can decrease if there is a decrease in plasma resistance, a change in stored magnetic energy, or a noninductive current source is present.
Canine Immunoglobulin E

Canine IgE discovery and characterization historically closely paralleled that of human IgE. The reason for this would seem to be the early recognition of the spontaneous manifestation of allergic diseases in dogs that are nearly identical to human allergic diseases. The discovery and characterization of human IgE being dependent upon its biological activity in sensitizing mast cells and basophils was matched early on by analogous approaches readily applied to dogs. Following the early work on IgE, cloning and sequencing of the IgE heavy chain, epsilon, lagged well behind the human and rodent for want of IgE producing canine myelomas. As with human allergic diseases, measurement of allergen-specific and total IgE in canine tissues and body fluids revealed the same associations with various disease manifestations that some times defied discovery of straight-forward cause and effect relationships because of the complexity of pathogenesis in spontaneous allergic disease. However it is clear that research on IgE in spontaneously allergic dogs offers many opportunities to explore novel immunotherapeutic approaches to the control of allergic disease that will benefit both dogs and humans.
Theory and Test Correlation for Laminate Stacking Factor Effect on Homopolar Bearing Stiffness

The effect of the laminate stacking factor on homopolar magnetic bearing performance is examined. Stacked laminates are used on the bearing rotor and in the stator. These laminate stacks have anisotropic permeability. Equations for the effect of the stacking factor on homopolar bearing position stiffness are derived. Numerical results are calculated and compared to measurements. These results provide an answer for the common discrepancy between test and theory for homopolar magnetic bearing position stiffnesses.
2-Nilpotent real section conjecture

We show a $$2$$ -nilpotent section conjecture over $$\mathbb{R }$$ : for a geometrically connected curve $$X$$ over $$\mathbb{R }$$ such that each irreducible component of its normalization has $$\mathbb{R }$$ -points, $$\pi _0(X(\mathbb{R }))$$ is determined by the maximal $$2$$ -nilpotent quotient of the fundamental group with its Galois action, as the kernel of an obstruction of Jordan Ellenberg. This implies that for $$X$$ smooth and proper, $$X(\mathbb{R })^{\pm }$$ is determined by the maximal $$2$$ -nilpotent quotient of $$\mathrm{Gal }(\mathbb{C }(X))$$ with its $$\mathrm{Gal }(\mathbb{R })$$ action, where $$X(\mathbb{R })^{\pm }$$ denotes the set of real points equipped with a real tangent direction, showing a $$2$$ -nilpotent birational real section conjecture.
Individual financial decisions in retirement saving plans: the role of participant-direction

Abstract Workers with individual retirement saving accounts often make decisions about contribution rates and asset allocation that affect ultimate retirement income. This paper presents econometric evidence from two data sets on the role that participant investment choice plays in asset allocation, contributions, and account balances. My preferred estimates indicate that participants with investment choice are 36 percent more likely to make an annual contribution. These participants are estimated to invest 13 percentage points more in stocks, contribute between one and three percentage points more of salary, and have at least $9000 more in their account than comparable participants without investment choice.
Reactor monitoring and safeguards using antineutrino detectors

Nuclear reactors have served as the antineutrino source for many fundamental physics experiments. The techniques developed by these experiments make it possible to use these very weakly interacting particles for a practical purpose. The large flux of antineutrinos that leaves a reactor carries information about two quantities of interest for safeguards: the reactor power and fissile inventory. Measurements made with antineutrino detectors could therefore orer an alternative means for verifying the power history and fissile inventory of a reactors, as part of International Atomic Energy Agency (IAEA) and other reactor safeguards regimes. Several erorts to develop this monitoring technique are underway across the globe.
Synthesis, structure and characterization of a new tellurate: NaBiTeO5

Abstract A new tellurate, NaBiTeO 5 has been synthesized by standard solid-state techniques using Na 2 CO 3 , Bi 2 O 3 , and TeO 2 as reagents. The structure of NaBiTeO 5 was determined by single crystal X-ray diffraction. NaBiTeO 5 crystallizes in the monoclinic space group P2 1 /c (No. 14), with a =7.2645(5), b =9.8048(6), c =6.2718(4) A, β =106.819(1)°, V =427.61(5) A 3 and Z =4. NaBiTeO 5 has a novel three-dimensional framework consisting of chains of [TeO 6/2 ] 0 octahedra that are linked by [BiO 4/2 ] − polyhedra. Bi 3+ is in an asymmetric coordination environment attributable to its lone-pair. The lone-pair on the Bi 3+ point in the [1 0 0] and [0 0 −1] directions and interacts with the Na + cation. Infrared and thermogravimetric analyzes are also presented.
The Dynamic Effects of Money: Combining Short-Run and Long-Run Identifying Restrictions Using Bayesian Techniques

This paper proposes a Bayesian approach to incorporating specification and identification uncertainty into a VAR analysis of the dynamic effects of money supply shocks on the macroeconomy. The approach follows Poirier (1991) in averaging over discrete model specifications in forming posterior densities of the dynamic responses to such shocks. Two distinct means of identifying money supply shocks are considered here: one that imposes contemporaneous restrictions, and one that imposes long-run monetary neutrality. I estimate bounds on dynamic responses that account for specification and parameter uncertainty, and find strong evidence of short-run real effects of money on the economy, including a liquidity effect for both long-term and short-term interest rates. Furthermore, some results differ substantially across identifying restrictions if model uncertainty is ignored.
Learning Control Systems-Review and Outlook

The basic concept of learning control is introduced. The following five learning schemes are briefly reviewed: 1) trainable controllers using pattern classifiers, 2) reinforcement learning control systems, 3) Bayesian estimation, 4) stochastic approximation, and 5) stochastic automata models. Potential applications and problems for further research in learning control are outlined.
[3,3]-Rearrangements of phosphonium ylides

Allylic phosphonium ylides are readily generated by the combination of an allylic alcohol, a carbene, and a chlorophosphite. Here we demonstrate that these intermediates undergo a thermal [3,3]-rearrangement to provide single isomers of homoallylic phosphonates in good to excellent yields. This new reaction manifold for phosphorus ylides is tolerant of a range of substitution patterns on the reactants and provides access to structurally complex intermediates for the synthesis of enzyme inhibitors, aminophosphonic acids, and natural products.
α-Halogenation of carbonyl compounds: halotrimethylsilane–nitrate salt couple as an efficient halogenating reagent system

Abstract A mixture of chloro/bromotrimethylsilane and nitrate salt is found to be an effective reagent system for the α-chlorination/bromination of carbonyl compounds. The reaction occurs under mild conditions yielding the products in moderate to good yields.
The eternal sunshine of the spotless mind

We extend the worldline measure for pocket formation in eternal inflation to allow for time-ordered bubble formation. Such a time-ordering is equivalent to imposing a preferred time-slicing on the 'parent' de Sitter space. Using this measure, we describe a covariant version of the youngness paradox and show that the youngness paradox is a gauge artifact if the parent spacetime is an unbroken de Sitter space, due to the lack of an explicit time-ordering for the bubble nucleation events. We then show that one can add a 'clock' to the de Sitter space, in the form of a vector field with a spontaneously broken symmetry that defines a unique timelike direction accessible to all observers. Once this is done, the existence of a preferred slicing means that the youngness paradox cannot be easily resolved. We use this to elucidate the apparent 'persistence of memory' discussed recently by Garriga, Guth and Vilenkin, for inflationary universes produced by bubble nucleation.
The physics of the centrality dependence of elliptic flow

Abstract The centrality dependence of elliptic flow and how it is related to the physics of expansion of the system created in high energy nuclear collisions is discussed. Since in the hydro limit the centrality dependence of elliptic flow is mostly defined by the elliptic anisotropy of the overlapping region of the colliding nuclei, and in the low density limit by the product of the elliptic anisotropy and the multiplicity, we argue that the centrality dependence of elliptic flow should be a good indicator of the degree of equilibration reached in the reaction. Then we analyze experimental data obtained at AGS and SPS energies. The observed difference in the centrality dependence of elliptic flow could imply a transition from a hadronic to a partonic nature of the system evolution. Finally we exploit the multiplicity dependence of elliptic flow to make qualitative predictions for RHIC and LHC.
Safety of Medical Excimer Lasers with an Emphasis on Compressed Gases

Excimer lasers which emit short ultraviolet radiation (UVR) are currently being used in experimental and developmental surgical applications. Although UVR exposure is possible, it is not normal in laser angioplasty (cardiovascular surgery) and is insignificant in photokera‐toplasty (ophthalmic surgery). However, significant potential hazards exist with the use of excimer laser gases such as fluorine and HCI. Stringent safeguards for handling and use are required when these gases are employed in a clinical setting. Recommended safety measures are provided.
Seasonal and solar activity dependence of the generalized polar wind with low‐altitude auroral ion energization

[1] The effects of low-altitude energization (LAE) of ions on the dynamic behavior of the high-latitude plasma was investigated using a macroscopic particle-in-cell (mac-PIC) model. The model simulates the behavior of a plasma-filled flux tube as it drifts across the different high-latitude regions (cusp, polar cap, auroral, and subauroral regions). In addition to the LAE, the model properly accounts for gravity, electrostatic field, magnetic mirror force, ion-ion collisions, wave-particle interactions, magnetospheric electrons, and centrifugal acceleration. However, the focus here is on the effects of the LAE and their seasonal dependence. The LAE was emulated by uniform energization of the ions in the perpendicular direction as they pass through a narrow domain (200 km in altitude) that is embedded within the cusp/auroral oval region. The roles that season, solar activity, and the altitude of the LAE play, with regard to the effects of the LAE on the plasma characteristics, were studied. In particular, several simulation runs were performed for different seasons (summer/winter), for different solar activity levels, and for different altitudes of the LAE region. Comparing the results from these runs, the following conclusions can be drawn: (1) When the LAE occurs at high altitudes, where less O+ exists, it does not appreciably enhance the O+ escape flux. The O+ escape flux for LAE occurring above ∼3000 km is almost identical to the case with no LAE. (2) In the absence of LAE, the dominant source of escaping O+ occurs in the polar cap due to magnetospheric electrons. (3) Both upward and downward O+ fluxes occur at low altitudes, while only upward O+ fluxes occur at high altitudes. (4) As the plasma drifts from the polar cap into the auroral region, it is (first) depleted due to the rapid energization associated with wave-particle interactions (WPI) and then it is slowly replenished due to the effect of the LAE. (5) In general, the cases of summer-solar maximum and winter-solar minimum produce the two extreme results, while the other two cases (summer-solar minimum and winter-solar maximum) produce intermediate results. For example, the largest O+ escape fluxes were found for the case of (summer-solar maximum) and the smallest fluxes were found for the case of (winter-solar minimum).
Analysis of ablation debris from natural and artificial iron meteorites

Artificial ablation studies were performed on iron and nickel-iron samples using an arc-heated plasma of ionized air. Experiment conditions simulated a meteoroid traveling about 12 km/sec at an altitude of 70 km. The artificially produced fusion crusts and ablation debris show features very similar to natural fusion crusts of the iron meteorites Boguslavka, Norfork, and N'Kandhla and to magnetic spherules recovered from Mn nodules. X-ray diffraction, electron microprobe, optical, and scanning electron microscope analyses reveal that important mineralogical, elemental, and textural changes occur during ablation. Some metal is melted and ablated. The outer margin of the melted rind is oxidized and recrystallizes as a discontinuous crust of magnetite and wustite. Adjacent to the oxidized metallic ablation zone is an unoxidized metallic ablation zone in which structures such as Widmannstatten bands are obliterated as the metal is transformed to unequilibrated alpha 2 nickel-iron. Volatile elements are vaporized and less volatile elements undergo fractionation.
Effects of Rotation on the Minimum Mass of Primordial Progenitors of Pair-instability Supernovae

The issue of which stars may reach the conditions of electron/positron pair-formation instability is of importance to understand the final evolution both of the first stars and of contemporary stars. The criterion to enter the pair-instability regime in density and temperature is basically controlled by the mass of the oxygen core. The main-sequence masses that produce a given oxygen core mass are, in turn, dependent on metallicity, mass loss, and convective and rotationally induced mixing. We examine the evolution of massive stars to determine the minimum main-sequence mass that can encounter pair-instability effects, either a pulsational pair-instability supernova (PPISN) or a full-fledged pair-instability supernova (PISN). We concentrate on zero-metallicity stars with no mass-loss subject to the Schwarzschild criterion for convective instability, but also explore solar metallicity and mass loss and the Ledoux criterion. As expected, for sufficiently strong rotationally induced mixing, the minimum main-sequence mass is encountered for conditions that induce effectively homogeneous evolution such that the original mass is converted almost entirely to helium and then to oxygen. For this case, we find that the minimum main-sequence mass is about 40 M ☉ to encounter PPISN and about 65 M ☉ to encounter a PISN. The implications of these results for the first stars and for contemporary supernovae are discussed.
Expressing the operations of quantum computing in multiparticle geometric algebra

We show how the basic operations of quantum computing can be expressed and manipulated in a clear and concise fashion using a multiparticle version of geometric (aka Clifford) algebra. This algebra encompasses the product operator formalism of NMR spectroscopy, and hence its notation leads directly to implementations of these operations via NMR pulse sequences.
Of Roots and Race: Discourses of Body and Place in Japanese Taiko Drumming

This article examines the relationships among body, place, and identity in contemporary Japan through an analysis of the aesthetic discourse of taiko drumming. Employing the concept of habitus, the article focuses on the body as an important means through which discourses of national and local identity are constructed in Japan. On the one hand, toiko aesthetics invert a perceived sense of physical 'inferiority' many Japanese feel towards foreigners by emphasizing the close connection between stereotypically Japanese bodies and Japanese culture. On the other hand, this same aesthetic discourse creates an opposition by which the inhabitants ofJapan's rural periphery are imagined to embody a deeper relationship to local culture than cosmopolitan urbanites can ever achieve. Thus, while in the first place, a sense of national identity emerges out of the appeal to racial similarities, taiko aesthetics ultimately fragment this unity by emphasizing just as strongly rooted distinctions in regional differences.
Central Pattern Generators

Grillner S, et al.: Neural networks that co-ordinate locomotion and body orientation in lamprey.Trends Neurosci 1995, 18:270-279.Marder E, Calabrese RL: Principles of rhythmic motor pattern production.Physiol Rev 1996, 76:687-717.Stein PSG, Grillner S, Selverston AI, Stuart DG: Neurons, Networks and Behavior. Cambridge, USA: MIT Press; 1997.
A PROTECTED FORM OF (1S,2R,3S,4R)-4-AMINOCYCLOPENTANE-1,2,3-TRIOL, A USEFUL PRECURSOR TO 5′-NOR CARBOCYCLIC NUCLEOSIDES

5′-Nor carbocyclic nucleosides have been found to possess a variety of meaningful biological properties. One of the building blocks for this class of compounds is (1S,2R,3S,4R)-4-aminocyclopentane-1,2,3-triol. To date, the reported routes to this compound are not particularly facile. Thus, a convenient route to this triol in its protected isopropylidene form (2) from (+)-(1R,4S)-4-hydroxy-2-cyclopenten-1-yl acetate. This will facilitate the preparation of new 5′-nor carbocyclic nucleosides in the “D-ribo-like” configuration. This method is also adaptable to the “L-like” series and the 2′- and 3′-deoxy analogs.
Low levels of mercury inhibit the respiratory burst in human polymorphonuclear leukocytes

Abstract The objective of this investigation was to examine the effects of low levels of Hg(II) on the respiratory burst of PMNs by monitoring O 2 consumption, superoxide radical formation, and chemiluminescence. Hg(II) at concentration of 10–100 ng/ml profoundly inhibited zymosan-stimulated human cells. This inhibition was immediate in onset and occurred with minimal loss of cell viability. Effects of Hg(II) on the PMN respiratory burst were compared with those of Sn, Pb, Se, Au, Ag and Cu. Only in the case of Ag and Cu did the inhibitory effects approach those of Hg. The results indicate that Hg(II) may serve as a specific inhibitor of components of the respiratory burst.
Controlled diastereo- and enantioselection in a catalytic asymmetric aziridination.

Chiral polyborate based Bronsted acids prepared from the VANOL and VAPOL ligands are known to catalyze the reaction of diarylmethyl imines with diazoesters to give cis-aziridines. In the present work, this same catalyst is shown to catalyze the reaction of the same imines with diazoacetamides to give trans-aziridines with the same high asymmetric inductions as seen with cis-aziridines, enabling the development of an unprecedented universal catalytic asymmetric aziridination protocol. The substrate scope is broad and includes imines prepared from both electron-rich and electron-poor aromatic aldehydes and also from 1°, 2°, and 3° aliphatic aldehydes. The face selectivity of the addition to the imine was found to be independent of the diazo compounds. The (S)-VANOL or (S)-VAPOL derived catalyst will cause both diazoesters and diazoacetamides to add to the Si-face of the imine when cis-aziridines are formed and both to add to the Re-face of the imine when trans-aziridines are formed.
An estimate of the length of the DNA molecule of T2 bacteriophage by autoradiography.

T2 bacteriophage, labelled with [ 3 H]thymidine or [ 3 H]thymine, is subject to suicide on storage. The efficiency of suicide from 3 H-decay is apparently the same as that from 32 P-decay. Autoradiography of T2 DNA, labelled with [ 3 H]thymine and extracted in the presence of 1000-fold excess of cold T2, shows that the molecule can assume the form of an unbranched rod about 52 μ long. If the molecule is throughout its length a double helix in the B configuration, this indicates a molecular weight of 110 × 10 6 .
Arrangements and local systems

We use stratified Morse theory to construct a complex to compute the cohomology of the complement of a hyperplane arrangement with coefficients in a complex rank one local system. The linearization of this complex is shown to be the Orlik-Solomon algebra with the connection operator. Using this result, we establish the relationship between the cohomology support loci of the complement and the resonance varieties of the Orlik-Solomon algebra for any arrangement, and show that the latter are unions of subspace arrangements in general, resolving a conjecture of Falk. We also obtain lower bounds for the local system Betti numbers in terms of those of the Orlik-Solomon algebra, recovering a result of Libgober and Yuzvinsky. For certain local systems, our results provide new combinatorial upper bounds on the local system Betti numbers. These upper bounds enable us to prove that in non-resonant systems the cohomology is concentrated in the top dimension, without using resolution of singularities.
New affine-invariant codes from lifting

In this work we explore error-correcting codes derived from the "lifting" of "affine-invariant" codes. Affine-invariant codes are simply linear codes whose coordinates are a vector space over a field and which are invariant under affine-transformations of the coordinate space. Lifting takes codes defined over a vector space of small dimension and lifts them to higher dimensions by requiring their restriction to every subspace of the original dimension to be a codeword of the code being lifted. While the operation is of interest on its own, this work focusses on new ranges of parameters that can be obtained by such codes, in the context of local correction and testing. In particular we present four interesting ranges of parameters that can be achieved by such lifts, all of which are new in the context of affine-invariance and some may be new even in general. The main highlight is a construction of high-rate codes with sublinear time decoding. The only prior construction of such codes is due to Kopparty, Saraf and Yekhanin [33]. All our codes are extremely simple, being just lifts of various parity check codes (codes with one symbol of redundancy), and in the final case, the lift of a Reed-Solomon code.We also present a simple connection between certain lifted codes and lower bounds on the size of "Nikodym sets". Roughly, a Nikodym set in Fqm is a set S with the property that every point has a line passing through it which is almost entirely contained in S. While previous lower bounds on Nikodym sets were roughly growing as qm/2m, we use our lifted codes to prove a lower bound of (1 - o(1))qm for fields of constant characteristic.
The imaginary-time path integral and non-time-reversal-invariant saddle points of the Euclidean action

Abstract We discuss new bounce-like (but non-time-reversal-invariant) solutions to Euclidean equations of motion, which we dub boomerons. In the Euclidean path integral approach to quantum theories, boomerons make an imaginary contribution to the vacuum energy. The fake vacuum instability can be removed by cancelling boomeron contributions against contributions from time reversed boomerons (anti-boomerons). The cancellation rests on a sign choice whose significance is not completely understood in the path integral method.
Synthesis and reactions of silanes containing two triflate groups

Abstract 1,2-Bis(trifluoromethanesulfonyloxy)tetramethyldisilane ( 1 ) and dimethylsilylbis-(trifluoromethanesulfonate) ( 2 ) have been prepared via displacement of phenyl, chloro, and methyl groups in the corresponding mono- and di-silanes. Phenyl groups are displaced more rapidly than chloro and methyl groups. The unreacted groups are strongly deactivated by the presence of a triflate group at the same silicon atom. The deactivation is much weaker when a triflate group is present at the adjacent silicon atom. Alcohols and amines react more rapidly with ditriflates than with monotriflates.
Iron-Catalyzed Formation of 2-Aminopyridines from Diynes and Cyanamides

Diynes and cyanamides undergo an iron-catalyzed [2 + 2 + 2] cycloaddition to form highly substituted 2-aminopyridines in an atom-efficient manner that is both high yielding and regioselective. This system was also used to cyclize two terminal alkynes and a cyanamide to afford a 2,4,6-trisubstituted pyridine product regioselectively.