cssi/SciSciGPT-SciSciNet huggingface dataset:
New aspects of whistler waves driven by an electron beam studied by a 3-D electromagnetic code

Abstract We have restudied electron beam driven whistler waves with a 3-D electromagnetic particle code. In the initialisation of the beam-plasma system, “quiet start” conditions were approached by including the poloidal magnetic field due to the current carried by beam electrons streaming along a background magnetic field. The simulation results show electromagnetic whistler wave emissions and electrostatic beam modes like those observed in the Spacelab 2 electron beam experiment. It has been suggested in the past that the spatial bunching of beam electrons associated with the beam mode may directly generate whistler waves. However, the simulation results indicate several inconsistencies with this picture: (1) the parallel (to the background magnetic field) wavelength of the whistler wave is longer than that of the beam instability, (2) the parallel phase velocity of the whistler wave is smaller than that of the beam mode, and (3) whistler waves continue to be generated even after the beam mode space charge modulation looses its coherence. The complex structure of the whistler waves in the vicinity of the beam suggest that the transverse motion (gyration) of the beam and background electrons is involved in the generation of the whistler waves.
The Coronal Abundances of Mid-F Dwarfs

A Chandra spectrum of the moderately active nearby F6 V star π3 Ori is used to study the coronal properties of mid-F dwarfs. We find that π3 Ori's coronal emission measure distribution is very similar to those of moderately active G and K dwarfs, with an emission measure peak near log T = 6.6 seeming to be ubiquitous for such stars. In contrast to coronal temperature, coronal abundances are known to depend on spectral type for main sequence stars. Based on this previously known relation, we expected π3 Ori's corona to exhibit an extremely strong first ionization potential (FIP) effect, a phenomenon first identified on the Sun where elements with low FIP are enhanced in the corona. We instead find that π3 Ori's corona exhibits a FIP effect essentially identical to that of the Sun and other early G dwarfs, perhaps indicating that the increase in FIP bias toward earlier spectral types stops or at least slows for F stars. We find that π3 Ori's coronal characteristics are significantly different from two previously studied mid-F stars, Procyon (F5 IV-V) and τ Boo (F7 V). We believe π3 Ori is more representative of the coronal characteristics of mid-F dwarfs, with Procyon being different because of luminosity class, and τ Boo being different because of the effects of one of two close companions, one stellar (τ Boo B: M2 V) and one planetary.
Adiabatic Quantum Simulation of Quantum Chemistry

We show how to apply the quantum adiabatic algorithm directly to the quantum computation of molecular properties. We describe a procedure to map electronic structure Hamiltonians to 2-body qubit Hamiltonians with a small set of physically realizable couplings. By combining the Bravyi-Kitaev construction to map fermions to qubits with perturbative gadgets to reduce the Hamiltonian to 2-body, we obtain precision requirements on the coupling strengths and a number of ancilla qubits that scale polynomially in the problem size. Hence our mapping is efficient. The required set of controllable interactions includes only two types of interaction beyond the Ising interactions required to apply the quantum adiabatic algorithm to combinatorial optimization problems. Our mapping may also be of interest to chemists directly as it defines a dictionary from electronic structure to spin Hamiltonians with physical interactions.
Oxidation resistance of B2 rare earth–magnesium intermetallic compounds

The oxidation behaviors of YMg and CeMg were measured in flowing air using the thermal gravimetric analysis technique. Negligible oxidation is observed at room temperature in both compounds. At elevated temperatures, the rare earth metals oxidize preferentially, while the underlying materials transform into Mg-rich intermetallics before the Mg oxidizes to MgO. The oxidation resistance of YMg is several orders of magnitude greater than that of CeMg. The oxidation of YMg follows parabolic kinetics with an activation energy of 104 kJ/mol while that of CeMg obeys a linear law with an activation energy of 136 kJ/mol.
Constraints on Neutron Star Properties from X-Ray Observations of Millisecond Pulsars

We present a model of thermal X-ray emission from hot spots on the surface of a rotating compact star with an unmagnetized light-element atmosphere. An application to ROSAT, Chandra, and XMMNewton X-ray observations of the nearest known rotation-powered millisecond pulsar (MSP) PSR J0437–4715 reveals that the thermal emission from this pulsar is fully consistent with such a model, enabling constraints on important properties of the underlying neutron star. We confirm that the observed thermal X-ray pulsations from J0437–4715 are incompatible with blackbody emission and require the presence of an optically thick, light element (most likely hydrogen) atmosphere on the neutron star surface. The morphology of the X-ray pulse profile is consistent with a global dipole configuration of the pulsar magnetic field but suggests an off-center magnetic axis, with a displacement of 0.8 −3 km from the stellar center. For an assumed mass of 1.4 M⊙, the model restricts the allowed stellar radii to R = 6.8 − 13.8 km (90% confidence) and R > 6.7 km (99.9% confidence), which is consistent with standard NS equations of state and rules out an ultracompact star smaller than its photon sphere. Deeper spectroscopic and timing observations of this and other nearby radio MSPs with current and future X-ray facilities (Constellation-X and XEUS) can provide further insight into the fundamental properties of neutron stars. Subject headings: pulsars: general — pulsars: individual (PSR J0437–4715) — stars: neutron — X-rays: stars — gravitation — relativity
DESIGN SENSITIVITY ANALYSIS AND OPTIMIZATION OF NONLINEAR TRANSIENT DYNAMICS

A shape design sensitivity analysis (DSA) and optimization of structural transient dynamics are proposed for the finite deformation elastoplastic materials under impact with a rigid surface. A shape variation of the structure is considered using the material derivative approach in continuum mechanics. Hyperelasticitybased multiplicatively decomposed elastoplasticity is used for the constitutive model. The implicit Newmark time integration scheme is used for the structural dynamics. The design sensitivity equation is solved at each converged time step with the same tangent stiffness matrix as response analysis without iteration. The cost of sensitivity computation is more efficient than the cost of response analysis for the implicit time integration method. The efficiency and the accuracy of the proposed method are shown through the design optimization of a vehicle bumper.
Monolithic and Mechanical Multijunction Space Solar Cells

High-efficiency, lightweight, radiation-resistant solar cells are essential to meet the large power requirements of future space missions. Single-junction cells are limited in efficiency. Higher cell efficiencies could be realized by developing multijunction, multibandgap solar cells. Monolithic and mechanically stacked tandem solar cells surpassing single-junction cell efficiencies have been fabricated. This article surveys the current status of monolithic and mechanically stacked multibandgap space solar cells, and outlines problems yet to be resolved. The monolithic and mechanically stacked cells each have their own problems related to size, processing, current and voltage matching, weight, and other factors. More information is needed on the effect of temperature and radiation on the cell performance. Proper reference cells and full-spectrum range simulators are also needed to measure efficiencies correctly. Cost issues are not addressed, since two approaches are still in the developmental stage.
Gravitational instability of polytropic spheres and generalized thermodynamics

We extend the existing literature on the structure and stability of polytropic gas spheres reported in the classical monograph of Chandrasekhar (1932). For isolated polytropes with index 1 <n< 5, we provide a new, alternative, proof that the onset of gravitational instability occurs for n = 3 and we express the perturbation proles of density and velocity at the point of marginal stability in terms of the Milne variables. Then, we consider the case of polytropes conned within a box of radius R (an extension of the Antonov problem for isothermal gas spheres). For n 3, the mass-density relation presents damped oscillations and there exists a limiting mass above which no hydrostatic equilibrium is possible. As for isothermal gas spheres, the onset of instability occurs precisely at the point of maximum mass in the series of equilibrium. Analytical results are obtained for the particular index n = 5. We also discuss the relation of our study with generalized thermodynamics (Tsallis entropy) recently investigated by Taruya & Sakagami (2002).
Synthesis, processing, assembly and activation of core-shell structured gold nanoparticle catalysts

This paper describes recent progress of an investigation of the synthesis, processing, assembly and activation of gold nanoparticles that are of potential interest to fuel cell catalysis. Core-shell type gold nanoparticles of a few nanometer core size with organic monolayer encapsulation are highlighted. The activation of the core-shell nanoparticle assemblies towards nanostructured catalyst for potential fuel cell catalytic reactions is discussed. The understanding of the control factors in terms of nanocrystal size and interparticle spatial properties has important implications to the design of highly active nanogold catalysts for practical applications.
Deep dielectric charging effects due to high-energy electrons in earth's outer magnetosphere

Abstract Many spacecraft operational problems in the earth's outer magnetosphere appear to be due to intense, transient radiation phenomena. Three types of naturally occuring, and highly variable, hostile particle radiation environments are encountered at, or near, the geostationary orbit: (1) high-energy protons due to solar flares; (2) energetic ions and electrons produced by magnetospheric substorms; and (3) very-high-energy electrons of uncertain origin. In this paper, particular emphasis is given to highly relativistic electrons (3–10 MeB). Electron fluxes and energy spectra are shown which were measured by two high-energy electron sensory systems at 6.6 R E from 1979 through 1984. Large, persistent increases in this population were found to be relatively infrequent and sporadic in 1978-81 around solar maximum. During the approach to solar minimum (1981-present) it is observed that the highly relastivistic electrons occur with occur with a regular 27-day periodicity, and are well associated with the re-established solar wind stream structures. Through a superposed epoch analysis technique we show that an energetic electron enhancement typically rises on 2- to 3-day time scale and decays on 3- to 4-day scale at essentially all energies above ca. 3 MeV. The present analysis suggests that these electrons have a very deletrious influence on spacecraft systems due to deep dielectric charging and low-dose susceptibility effects.
The effect of environmental rigidity on nonradiative decay in chromium(III) amines

Abstract The lifetimes of Cr(NH 3 ) 6 3+ and the Cr(cyclam)(NH 3 ) 2 + complexes, both protiated and deuterated, have been recorded in aqueous polyalcoholic and DMSO solutions in the temperature range that includes the change from a rigid glass to a fluid. A small but distinct lifetime reduction is associated with increased solvent mobility in the protiated species but not in the deuterated complex. This is interpreted to indicate that increasing anharmonicity in accepting modes enhances the nonradiative rates.
Estrogen-based hormone therapy and thrombosis risk in women with essential thrombocythemia.

BACKGROUND There is currently insufficient evidence to either support or refute an association between estrogen-based hormone treatment (EBHT) and thrombosis risk in essential thrombocythemia (ET). METHODS A retrospective review of thrombotic events, which occurred both at diagnosis of ET and during subsequent follow-up, was performed in a consecutive cohort of women with WHO-defined ET seen at the Mayo Clinic. Details of EBHT were concomitantly obtained. RESULTS A total of 305 women were seen during the study period and followed for a median of 133 months. EBHT at diagnosis was documented in 59 women and such therapy was instituted at a variable time after diagnosis in 34 additional patients. At diagnosis, major thrombosis occurred in 73 patients (24%), including 11 of 59 (19%) on EBHT and 62 of 246 (25%) not on EBHT (P = .28). Thrombosis after diagnosis occurred in 94 patients (31%), including 64 of 212 (30%) not on EBHT, 5 of 17 (29%) in whom EBHT was discontinued at diagnosis, 13 of 42 (31%) in whom EBHT was continued despite the diagnosis of ET, and 12 of 34 (35%) in whom EBHT was started after diagnosis (P = .95). The overall results were the same when arterial and venous events were analyzed separately. However, EBHT in the form of oral contraceptives (OCP) was associated with an increased risk of venous thrombosis (P = .03). CONCLUSIONS EBHT is safe in ET outside the setting of OCP use, which might be associated with an increased risk of deep vein thrombosis. Cancer 2006. © 2006 American Cancer Society.
CATECHOLAMINE MECHANISMS: THEIR PRESUMPTIVE ROLE IN THE GENERATION OF REM SLEEP PGO WAVES

Publisher Summary This chapter discusses the catecholamine (CA) mechanisms and their presumptive role in the generation of REM sleep PGO waves. The CA anti-synthesis agent alphamethyl-ptyrosine (AMPT) induces a severe depletion of brain CA when administered to cats. AMPT infused by way of an intravenous drip to avoid nephrotoxic side effects, depleted regional brain NE over 70%. This depletion was accompanied by an initial increase in both the per cent REM sleep of total sleep as well as the absolute amount of REM sleep. As administration was continued, slow-wave sleep time increased dramatically, such that at the height of the sleep effects SWS could itself account for over 60% of the 24 h recording time. During this peak effect on sleep no change in either the frequency, amplitudes, or temporal relationships of the REM PGO waves could be seen. On other hand, a significant increase in the absolute number of REM PGO waves was seen due to the initial increase in REM sleep time.
A New Measurement of Cosmic-Ray Composition at the Knee

The Dual Imaging Cerenkov Experiment (DICE) was designed and operated for making elemental composition measurements of cosmic rays near the knee of the spectrum at several PeV. Here we present the first results using this experiment from the measurement of the average location of the depth of shower maximum, Xmax, in the atmosphere as a function of particle energy. The value of Xmax near the instrument threshold of ~0.1 PeV is consistent with expectations from previous direct measurements. At higher energies, there is little change in composition up to ~5 PeV. Above this energy, Xmax is deeper than expected for a constant elemental composition, which implies that the overall elemental composition is becoming lighter above the knee region. These results disagree with the idea that cosmic rays should become on average heavier above the knee. Instead, they suggest a transition to a qualitatively different population of particles above 5 PeV.
Challenges in the aerodynamics modeling of an oscillating and translating airfoil at large incidence angles

Abstract The challenges in the modeling of the unsteady lift of a two-dimensional NACA 0012 airfoil oscillating and translating at large incidence angles are investigated in this paper. Forced oscillation motions with two reduced frequency values of 0.1 and 1.0 were used. The CFD results show that a hysteresis loop was developed in the lift variation with angle of attack; shapes of the loops change significantly with reduced frequency value. A dynamic stall vortex was identified in the pitching and plunging motions with k = 0.1 . This vortex delays the onset of flow separation over the upper surface to a higher incidence than would occur in steady conditions. The unsteady lift of the very fast motion is enhanced significantly due to the formation of a compression wave on the lower surface and an expansion wave on the upper surface. The results show clear limitations of unsteady aerodynamic theories for modeling motions at high incidences. Also, the CFD solution of indicial functions show a large oscillation at angles of attack beyond the stall angle, but the predictions of a model based on Radial Basis Function matches CFD values quite well.
Improving Nursing Home Care Through Training and Job Redesign

Nursing assistants have the primary contact with older residents of nursing homes. The Penn State Nursing Home Intervention Project's short-term longitudinal study assessed the single and combined effects of two interventions designed to affect nursing assistants' performance by increasing their knowledge and motivation: skills training and job redesign. Statistically significant differences in nursing assistants' knowledge were evident in comparisons between intervention and control sites, but performance was not improved. Implications for policy, practice, and research are discussed.
Classical height models with topological order

I discuss a family of statistical-mechanics models in which (some classes of) elements of a finite group G occupy the (directed) edges of a lattice; the product around any plaquette is constrained to be the group identity e. Such a model may possess topological order, i.e. its equilibrium ensemble has distinct, symmetry-related thermodynamic components that cannot be distinguished by any local order parameter. In particular, if G is a non-Abelian group, the topological order may be non-Abelian. Criteria are given for the viability of particular models, in particular for Monte Carlo updates.
Application of interactive parallel visualization for commodity-based clusters using visualization APIs

Abstract We present an efficient and inexpensive to develop application for interactive high-performance parallel visualization. We extend popular APIs such as Open Inventor and VTK to support commodity-based cluster visualization. Our implementation follows a standard master/slave concept: the general idea is to have a “Master” node, which will intercept a sequential graphical user interface and broadcast it to the “Slave” nodes. The interactions between the nodes are implemented using MPI. The parallel remote rendering uses Chromium. This paper is mainly the report of our implementation experiences. We present in detail the proposed model and key aspects of its implementation. Also, we present performance measurements, we benchmark and quantitatively demonstrate the dependence of the visualization speed on the data size and the network bandwidth, and we identify the singularities and draw conclusions on Chromium's sort-first rendering architecture. The most original part of this work is the combined use of Open Inventor and Chromium.
N-(4-bromobenzoyl)-S,S-dimethyliminosulfurane, a potent dermal penetration enhancer.

N-Aroyl-, N-Arylsulfonyl-, and N-Aryl-S,S-dimethyliminosulfuranes have been synthesized and evaluated as potential dermal penetration enhancers. The title compound and Azone® exhibit similar activities for permeation of hydrocortisone through hairless mouse skin.
Long-term Outcome of Hodgkin Disease Patients Following High-Dose Busulfan, Etoposide, Cyclophosphamide, and Autologous Stem Cell Transplantation

Abstract Busulfan (Bu)-based preparative regimens have not been extensively investigated in Hodgkin disease (HD). The purposes of this study were to investigate the toxicity and efficacy of a novel preparative regimen of Bu 14 mg/kg, etoposide 50-60 mg/kg, and cyclophosphamide 120 mg/kg in patients with primary refractory and relapsed HD. One hundred twenty-seven patients with a median age of 33 years (range, 14-67 years) underwent transplantation. The regimen was well tolerated, with 5.5% treatment-related mortality at 100 days after transplantation. With a median follow up of 6.7 years, the 5-year progression-free survival was 48 ± 5%, and the 5-year overall survival was 51 ± 5%. A Cox proportional hazards model identified refractory disease at time of transplantation as the only significant factor affecting relapse and overall survival, whereas disease bulk >10 cm affected overall survival. Five patients died between 5.3 and 9.3 years of late complications, including secondary myelodysplasia or acute myeloid leukemia, secondary solid malignancies, and pulmonary toxicity. This novel Bu regimen is comparable to other radiation-free preparative regimens in its effectiveness in the control of HD and with a low-risk of early treatment-related mortality.
A brief introduction to chiral perturbation theory

A brief introduction to the subject of chiral perturbation theory (Xpt) is presented, including a discussion of effective field theory and applications of Xpt in the arena of purely mesonic interactions as well as in the πN sector.
Ab initio many-body calculations of nucleon-nucleus scattering

We develop a new ab initio many-body approach capable of describing simultaneously both bound and scattering states in light nuclei, by combining the resonating-group method with the use of realistic interactions, and a microscopic and consistent description of the nucleon clusters. This approach preserves translational symmetry and the Pauli principle. We outline technical details and present phase-shift results for neutron scattering on $^{3}\mathrm{H}$, $^{4}\mathrm{He}$, and $^{10}\mathrm{Be}$ and proton scattering on $^{3,4}\mathrm{He}$, using realistic nucleon-nucleon ($\mathit{NN}$) potentials. Our $A=4$ scattering results are compared to earlier ab initio calculations. We find that the CD-Bonn $\mathit{NN}$ potential in particular provides an excellent description of nucleon-$^{4}\mathrm{He}S$-wave phase shifts. In contrast, the experimental nucleon-$^{4}\mathrm{He}P$-wave phase shifts are not well reproduced by any $\mathit{NN}$ potential we use. We demonstrate that a proper treatment of the coupling to the $n\text{\ensuremath{-}}^{10}\mathrm{Be}$ continuum is successful in explaining the parity-inverted ground state in $^{11}\mathrm{Be}$.
Johannes Theodoor Thijsse 1893–1984

On April 30, 1984, Professor Doctor Engineer J.T. Thijsse, professor emeritus of the Delft University of Technology, the Netherlands, passed away at the age of 91. Johannes T. Thijsse was born in Amsterdam, the Netherlands, in 1893, the son of a well-known Dutch biologist. He graduated from the Delft University of Technology in 1917 with a degree in civil engineering. In 1927, he became the first director of the newly formed Delft Hydraulics Laboratory, a function he continued until 1960. In 1936, Thijsse received a lectureship in hydraulics at the Delft University, to be followed in 1938 by his appointment as Professor Extraordinary and in 1946 as ordinary professor.
Short-sellers, fundamental analysis and stock returns *

Abstract Firms with low ratios of fundamentals (such as earning and book values) to market values are known to have systematically lower future stock returns. We document that short-sellers position themselves in the stock of such firms, and then cover their positions as the ratios mean-revert. We also show that short-sellers refine their trading strategies to minimize transactions costs and maximize their investment returns. Our evidence is consistent with short-sellers using information in these ratios to take positions in stocks with lower expected future returns.
Number theoretic properties of Wronskians of Andrews-Gordon series

For positive integers 1 ≤ i ≤ k, we consider the arithmetic properties of quotients of Wronskians in certain normalizations of the Andrews–Gordon q-series. This study is motivated by their appearance in conformal field theory, where these series are essentially the irreducible characters of Virasoro minimal models. We determine the vanishing of such Wronskians, a result whose proof reveals many partition identities. For example, if Pb(a;n) denotes the number of partitions of n into parts which are not congruent to 0, ±a (mod b), then for every positive integer n, we have We also show that these quotients classify supersingular elliptic curves in characteristic p. More precisely, if 2k + 1 = p, where p ≥ 5 is prime, and the quotient is non-zero, then it is essentially the locus of supersingular j-invariants in characteristic p.
The structure of adaptive competition in minority games

Abstract In this paper we present results and analyses of a class of games in which heterogeneous agents are rewarded for being in a minority group. Each agent possesses a number of fixed strategies each of which are predictors of the next minority group. The strategies use a set of aggregate, publicly available information (reflecting the agents’ collective previous decisions) to make their predictions. An agent chooses which group to join at a given moment by using one of his strategies. These games are adaptive in that agents can choose, at different points of the game, to exercise different strategies in making their choice of which group to join. The games are not evolutionary in that the agents’ strategies are fixed at the beginning of the game. We find, rather generally, that such systems evidence a phase change from a maladaptive, informationally efficient phase in which the system performs poorly at generating resources, to an inefficient phase in which there is an emergent cooperation among the agents, and the system more effectively generates resources. The best emergent coordination is achieved in a transition region between these two phases. This transition occurs when the dimension of the strategy space is of the order of the number of agents playing the game. We present explanations for this general behavior, based in part on an information theoretic analysis of the system and its publicly available information. We also propose a mean-field-like model of the game which is most accurate in the maladaptive, efficient phase. In addition, we show that the best individual agent performance in the two different phases is achieved by sets of strategies with markedly different characteristics. We discuss implications of our results for various aspects of the study of complex adaptive systems.
DEEP CCD SURFACE PHOTOMETRY OF GALAXY CLUSTERS. I. METHODS AND INITIAL STUDIES OF INTRACLUSTER STARLIGHT

We report the initial results of a deep imaging survey of galaxy clusters. The primary goals of this survey are to quantify the amount of intracluster light as a function of cluster properties and to quantify the frequency of tidal debris. We outline the techniques needed to perform such a survey, and we report findings for the first two galaxy clusters in the survey: A1413 and MKW 7. These clusters vary greatly in richness and structure. We show that our surface photometry reliably reaches to a surface brightness of μv = 26.5 mag arcsec-2. We find that both clusters show clear excesses over a best-fitting r1/4 profile: this was expected for A1413 but not for MKW 7. Both clusters also show evidence of tidal debris in the form of plumes and arclike structures, but no long tidal arcs were detected. We also find that the central cD galaxy in A1413 is flattened at large radii, with an ellipticity of ≈0.8, the largest measured ellipticity of any cD galaxy to date.
The effect of legal and extra-legal variables on the recommending and granting of a pardon

A familiar but little studied area of criminal justice is that of pardons. Using data from the Pennsylvania Board of Pardons, the decision-making process is examined to determine the degree of correspondence between the board’s recommendation and the governor’s decision to grant or deny a pardon. Included in the analysis is an assessment of the relative impact of legal and extra-legal variables on the decision-making process. The paper concludes with a discussion on the dynamics of the process, including why some individuals are more likely than others to be granted a pardon, and the implications the findings have for both policy and theory development.
Are There Topologically Charged States Associated with Quantum Electrodynamics

We present a generalization of quantum electrodynamics (QED) in terms of an antisymmetric tensor gauge field. In this formulation the topological current of this field appears as a source for the electromagnetic field and the topological charge therefore acts physically as an electric charge. The charged states of QED lie in the sector where the topological charge is identical to the matter charge. The antisymmetric field theory, however, admits new sectors where the topological charge is more general. These nontrivial, electrically charged sectors contain massless states orthogonal to the vacuum which are created by a gauge-invariant operator and can be interpreted as coherent states of photons. We evaluate the correlation functions of these states in the absence of matter. The new states have a positive definite norm and do interact with the charged states of QED in the usual way. It is argued that if these new sectors are in fact realized in nature, then a very intense background electromagnetic field is necessary for their experimental observation. The order of magnitude of the intensity threshold is estimated. The value of the quantum of charge is also obtained.
Constraints on reionization and source properties from the absorption spectra of z > 6.2 quasars

We make use of hydrodynamical simulations of the intergalactic medium (IGM) to create model quasar absorption spectra. We compare these model spectra with the observed Keck spectra of three z > 6.2 quasars with full Gunn-Peterson troughs: SDSS J1148+5251 (z = 6.42), SDSS J1030+0524 (z = 6.28), and SDSS J1623+3112 (z = 6.22). We fit the probability density distributions (PDFs) of the observed Lyα optical depths (τα) with those generated from the simulation by exploring a range of values for the size of the quasar's surrounding H II region, RS; the volume-weighted mean neutral hydrogen fraction in the ambient IGM, H I; and the quasar's ionizing photon emissivity, Q. In order to avoid averaging over possibly large sight line-to-sight line fluctuations in IGM properties, we analyze each observed quasar independently. We find the following results for J1148+5251, J1030+0524, and J1623+3112: the best-fit sizes RS are 40, 41, and 29 (comoving) Mpc, respectively. For the later two quasars, the value is significantly larger than the radius corresponding to the wavelength at which the quasar's flux vanishes. These constraints are tight, with only ~10% uncertainties, comparable to those caused by redshift determination errors. The best-fit values of Q are 2.1, 1.3, and 0.9 × 1057 s-1, respectively, with a factor of ~2 uncertainty in each case. Finally, the best-fit values of H I is not well constrained. However, for both J1030+0524 and J1623+3112, we find a significant lower limit of H I 0.033. Our method is different from previous analyses of the GP absorption spectra of these quasars, and our results strengthen the evidence that the rapid end stage of reionization is occurring near z ~ 6.
6-Propionyl-2-(N,N-dimethylamino) naphthalene (PRODAN) revisited

The photophysics of 6-propionyl-2-( N,N -dimethylamino)naphthalene (PRODAN) in liquid water are reported. Our results demonstrate that the often mentioned extra blue-edge shoulder seen for PRODAN in liquid water is a result of PRODAN-PRODAN intermolecular interactions in a supersaturated PRODAN solution and not a consequence of impurities in the commercial PRODAN preparations. In all cases where the aqueous PRODAN solution is not supersaturated, there is no detectable blue-edge emission shoulder.
Single-Atom Extraction by Scanning Tunneling Microscope Tip Crash and Nanoscale Surface Engineering

We report a novel atom extraction mechanism from the native substrate by means of a scanning tunneling microscope tip crash on a Ag(111) surface at 5 K. Individual atoms are scattered on the surface when a silver coated tip is dipped into the substrate at low tunneling biases. Quantitative analyses reveal that the mechanical energy supplied by the tip crash dominates the atom extraction process. Application of this procedure is demonstrated by constructing quantum structures using the extracted atoms on an atom-by-atom basis.
A study towards a unified approach to the joint estimation of objective and risk neutral measures for the purpose of options valuation

The purpose of this paper is to bridge two strands of the literature, one pertaining to the objective or physical measure used to model an underlying asset and the other pertaining to the risk-neutral measure used to price derivatives. We propose a generic procedure using simultaneously the fundamental price, St, and a set of option contracts [(σitI)i=1,m] where m⩾1 and σitI is the Black–Scholes implied volatility. We use Heston's (1993. Review of Financial Studies 6, 327–343) model as an example, and appraise univariate and multivariate estimation of the model in terms of pricing and hedging performance. Our results, based on the S&P 500 index contract, show dominance of univariate approach, which relies solely on options data. A by-product of this finding is that we uncover a remarkably simple volatility extraction filter based on a polynomial lag structure of implied volatilities. The bivariate approach, involving both the fundamental security and an option contract, appears useful when the information from the cash market reflected in the conditional kurtosis provides support to price long term.
Factoring 51 and 85 with 8 qubits

We construct simplified quantum circuits for Shor's order-finding algorithm for composites N given by products of the Fermat primes 3, 5, 17, 257 and 65537. Such composites, including the previously studied case of 15, as well as 51, 85, 771, 1285, 4369, … have the simplifying property that the order of a modulo N for every base a coprime to N is a power of 2, significantly reducing the usual phase estimation precision requirement. Prime factorization of 51 and 85 can be demonstrated with only 8 qubits and a modular exponentiation circuit consisting of no more than four CNOT gates.
Collisional Quenching of Highly Rotationally Excited HF

Context. Collisional excitation rate coe cients play an important role in the dynamics of energy transfer in the interstellar medium. In particular, accurate rotational excitation rates are needed to interpret microwave and infrared observations of the interstellar gas for nonlocal thermodynamic equilibrium line formation. Aims. Theoretical cross sections and rate coe cients for collisional deexcitation of rotationally excited HF in the vibrational ground state are reported. Methods. The quantum-mechanical close-coupling approach implemented in the nonreactive scattering code MOLSCAT was applied in the cross section and rate coe cient calculations on an accurate 2D HF-He potential energy surface. Estimates of rate coe cients for H and H2 colliders were obtained from the HF-He collisional data with a reduced-potential scaling approach. Results. The calculation of state-to-state rotational quenching cross sections for HF due to He with initial rotational levels up to j = 20 were performed for kinetic energies from 10 5 to 15 000 cm 1 . State-to-state rate coe cients for temperatures between 0.1 and 3000 K are also presented. The comparison of the present results with previous work for lowly-excited rotational levels reveals significant di erences. In estimating HF-H2 rate coe cients, the reduced-potential method is found to be more reliable than the standard reduced-mass approach. Conclusions. The current state-to-state rate coe cient calculations are the most comprehensive to date for HF-He collisions. We attribute the di erences between previously reported data and our results to di erences in the adopted interaction potential energy surfaces. The new He rate coe cients can be used in a variety of applications. The estimated H2 and H collision rates can also augment the smaller datasets previously developed for H2 and electrons.
Asymmetric Michael addition reactions of chiral Ni(II)-complex of glycine with (N-trans-enoyl)oxazolidines: improved reactivity and stereochemical outcome

Abstract Application of the ( N - trans -enoyl)oxazolidines as Michael acceptors in the kinetically controlled additions with a Ni(II)-complex of the chiral Schiff base of glycine with ( S )- o -[ N -( N -benzylprolyl)amino]benzophenone 1 was shown to be synthetically advantageous over the alkyl enoylates, allowing for remarkable improvement in reactivity and, in most cases, diastereoselectivity of the reactions. While the stereochemical outcome of the Michael additions of the aliphatic ( N - trans -enoyl)oxazolidines with complex 1 depended on the steric bulk of the alkyl group on the starting oxazolidines, the diastereoselectivity of the aromatic ( N - trans -enoyl)oxazolidines reactions was found to be controlled by the electronic properties of the aryl ring. In particular, the additions of complex 1 with ( N -cinnamoyl)oxazolidines, bearing electron-withdrawing substituents on the phenyl ring, afforded the (2 S ,3 R )-configured products with synthetically useful selectivity and in quantitative chemical yield, thus allowing an efficient access to sterically constrained β-substituted pyroglutamic acids and related compounds.
The Challenge of Equality Constraints in Robust Design Optimization: Examination and New Approach

In recent years, robust design optimization (RDO) has emerged as a significant area of research. The focus of RDO is to obtain a design that minimizes the effects of uncertainty on product reliability and performance. The effectiveness of the resulting solution in RDO highly depends on how the objective function and the constraints are formulated to account for uncertainties. Inequality constraint and objective function formulations under uncertainty have been studied extensively in the literature. However, the approaches for formulating equality constraints in the RDO literature are in a state of disharmony. Moreover, we observe that these approaches are generally applicable only to certain special cases of equality constraints. There is a need for a systematic approach for handling equality constraints in RDO, which is the motivation for this research. In this paper, we examine critical issues pertinent to formulating equality constraints in RDO. Equality constraints in RDO can be classified as belonging to two classes: (1) those that cannot be satisfied, because of the uncertainty inherently present in the RDO problem, and (2) those that must be satisfied, regardless of the uncertainty present in the problem. In this paper, we propose a linearization- based approach to classify equality constraints into the above two classes, and propose respective formulation methods. The theoretical developments presented in this paper are illustrated with the help of two numerical examples.
Asymptotics for a resonance-counting function for potential scattering on cylinders

Abstract We study certain resonance-counting functions for potential scattering on infinite cylinders or half-cylinders. Under certain conditions on the potential, we obtain asymptotics of the counting functions, with an explicit formula for the constant appearing in the leading term.
Heliconols A−C: Antimicrobial Hemiketals from the Freshwater Aquatic Fungus Helicodendron giganteum

Cultures of the freshwater aquatic fungus Helicodendron giganteum afforded three new compounds, heliconols A−C (1−3), that contain an unusual reduced furanocyclopentane unit. The structures of these metabolites were assigned by analysis of 1D and 2D NMR data. The absolute configuration of heliconol A (1) was assigned by single-crystal X-ray crystallographic analysis of its dibromobenzoate derivative. Heliconol A showed antifungal and antibacterial activities in disk diffusion assays.
Design and fabrication of low-cost X-ray mirrors

Traditional X-ray mirrors made from Zerodur and silicon carbide are quite expensive because of the fabrication cost involved in achieving a very high surface finish of the order of 15 A or better. The cost of X-ray mirrors can be greatly reduced by using replication methods for producing the grazing-incidence type mirrors. This paper presents the optical and optomechanical design for a Wolter type I mirror and its mount, and the fabrication method used to produce a low-cost replicated nickel mirror. The finite element analysis results for this mirror are also presented. The design and fabrication steps for the aluminium master mandrel used for replication are also discussed. A surface finish of better than 15 A was achieved for a such an electroformed mirror with a wall thickness of only 1 mm.
Physicians and Execution — Highlights from a Discussion of Lethal Injection

Foreword On January 14, 2008, the Journal hosted a videotaped roundtable discussion of the issues raised by Baze v. Rees, currently before the Supreme Court, that asks whether the three-drug protocol used to carry out the death penalty by lethal injection causes unnecessary pain and suffering in violation of the Constitutional ban on cruel and unusual punishment. Moderator Atul Gawande was joined by law professor Deborah Denno, anesthesiologist–ethicist Robert Truog, and anesthesiologist David Waisel. What follows are highlights of their discussion about lethal injection, the current protocol, possible alternatives, and the role of physicians and other health care professionals in putting convicted criminals to death. The video, along with a related reader poll and an interactive timeline, can be found at www.nejm.org. The Protocol Dr. David Waisel: The three-drug protocol is based on what was considered a normal induction of anesthesia when it was developed. [The first drug is] thiopental, also known as ...
Does Employer-Provided Health Insurance Constrain Labor Supply Adjustments to Health Shocks? New Evidence on Women Diagnosed with Breast Cancer

Employment-contingent health insurance may create incentives for ill workers to remain employed at a sufficient level (usually full-time) to maintain access to health insurance coverage. We study employed married women, comparing the labor supply responses to new breast cancer diagnoses of women dependent on their own employment for health insurance with the responses of women who are less dependent on their own employment for health insurance, because of actual or potential access to health insurance through their spouse's employer. We find evidence that women who depend on their own job for health insurance reduce their labor supply by less after a diagnosis of breast cancer. In the estimates that best control for unobservables associated with health insurance status, the hours reduction for women who continue to work is 8 to 11% smaller. Women's subjective responses to questions about working more to maintain health insurance are consistent with the conclusions from observed behavior.
Black hole growth by accretion

We show that black holes grow substantially by accretion at close to Eddington rates. Using a complete sample of soft X-ray selected AGNs, Grupe & Mathur (2004, ApJ, 606, L41) have shown that narrow line Seyfert 1 galaxies, as a class, lie below the MBH-σ relation of normal galaxies. Some NLS1s, however, lie on or close to the MBH-σ relation. Here we show that not all NLS1s accrete at close to Eddington rates: those with low L/LEddington are close to the MBH-σ relation, and those with high L/LEddington are far from it. With various tests in this paper, we argue that black holes grow in mass substantially in their high-accretion phase and approach the MBH-σ relation over time. The mass growth in a low accretion phase, as in BLS1s and also in some NLS1s, appears to be insignificant. Any theoretical model attempting to explain the MBH-σ relation needs to explain the above observations.
SELF-ORGANIZED CRITICAL MODEL OF BIOLOGICAL EVOLUTION

Abstract A punctuated equilibrium model of biological evolution with relative fitness between different species being the fundamental driving force of evolution is introduced. Mutation is modeled as a fitness updating cellular automation process where the change in fitness after mutation follows a Gaussian distribution with mean x > 0 and standard deviation σ. Scaling behaviors are observed in our numerical simulation, indicating that the model is self-organized critical. Besides, the numerical experiment suggests that models with different x and σ belongs to the same universality class.
Exact BER computation of generalized hierarchical PSK constellations

We obtain in this paper generic expressions in M for the exact bit-error rate of the generalized hierarchical 2/4//spl middot//spl middot//spl middot//M-phase-shift keyed constellations over additive white Gaussian noise (AWGN) and fading channels. For the AWGN case, these expressions are in the form of a weighted sum of Pawula F-functions and are solely dependent on the constellation size M, the carrier-to-noise ratio, and a constellation parameter which controls the relative message importance. The mathematical expressions are illustrated with some select numerical examples.
Teacher Professional Growth in an Authentic Learning Environment

AbstractIncrements in educational budgets have been devoted to professional development for teachers to help them accommodate their practices to the realities of their classrooms. Previous research has suggested that despite this significant investment, there has been little, if any, positive change. This begs the question of what else might be done to reverse this outcome and contribute to transformational change of the profession. This article reports on a study that closely followed and documented the journeys of professional growth for a group of teachers from their points of view, over a period of six months. Action research was conducted in conjunction with participation in a project centred on the creation of Web sites as culminating performance tasks. Analysis of the data collected led to the conclusion that one possibility could be to facilitate professional development in such a way that it is authentic, based in the classroom and focused on tasks meaningful to and specifically chosen by the tea...