bluuebunny/crossref_metadata_2025 huggingface dataset:
Analyses of the optical and magneto-optical spectra of Tb3Ga5O12
Authors: Gruber John B. , Sardar Dhiraj K. , Yow Raylon M. , Valiev U. V. , Mukhammadiev A. K. , Sokolov V. Yu. , Amin Irina , Lengyel K. , Kachur I. S. , Piryatinskaya Valeriya G. , Zandi Bahram
Published: February 2007

Absorption spectra of the FJ7, D4,3,25, G6,5,45, and L10,95 multiplet manifolds of Tb3+ (4f8) in D2 sites in cubic garnet Tb3Ga5O12 (TbGaG) are investigated at sample temperatures between 1.8K and room temperature. Absorption measurements extend from 5000to340nm. From analyses of temperature-dependent (hot-band) absorption spectra, many of the crystal-field split energy (Stark) levels of the LJ2S+1 multiplet manifolds of Tb3+ are identified and confirmed from analyses of the fluorescence spectra observed between 485 and 680nm, representing transitions from the D45 to the FJ7 manifolds. Each manifold is split by the crystal field into 2J+1 Stark levels. Some of these manifolds, including the ground-state manifold F67, consist of Stark levels that are accidentally degenerate, or nearly so, making transitions to or from these levels appear as unresolved spectra, even at the lowest temperature investigated (1.8K). To resolve these spectra, we have investigated the Zeeman and magneto-optical spectra for representative manifolds D45, F57, and F67 at temperatures of 78 and 85K and magnetic fields up to 7kOe. The data are interpreted using the Stark levels and wave functions from a crystal-field splitting calculation that involved 80 individual Stark levels identified from the optical spectra of the FJ7 and quintet states reported in this study. Good agreement is obtained between the calculated and the experimental Stark levels. The calculated energy and symmetry label for each Stark level in the D45, F57, and F67 manifolds suitably interpret the spectral properties observed in the magneto-optical spectra, including the experimental assignment reported in the literature for the ground state as a quasidoublet {Γ1,Γ2}.
Smart resolution replica exchange: An efficient algorithm for exploring complex energy landscapes
Authors: Liu Pu , Voth Gregory A.
Published: February 2007

A coarse-grained representation of a condensed phase system can significantly reduce the number of system degrees of freedom, making coarse-grained simulations very computationally efficient. Moreover, coarse graining can smoothen the free energy landscape of the system. Thus coarse-grained dynamics is usually faster than its fully atomistic counterpart. In this work, the smart resolution replica exchange method is introduced that incorporates the information from coarse-grained simulations into atomistic simulations in order to accelerate the sampling of rough, complex atomistic energy landscapes. Within this methodology, interactions between particles are defined by a potential energy that interpolates between a fully atomistic potential and a fully coarse-grained effective potential according to a parameter λ. Instead of exchanging the configurations from neighboring resolutions directly, as has been done in the resolution replica exchange methods [E. Lyman et al., Phys. Rev. Lett. 96, 028105 (2006); M. Christen and W. F. v. Gunsteren, J. Chem. Phys. 124, 154106 (2006)], the configuration described at the coarser resolution is first relaxed before an exchange is attempted, similar to the smart walking method [R. Zhou and B. J. Berne, J. Chem. Phys. 107, 9185 (1997)]. This approach greatly increases the acceptance ratio of exchange and only two replicas, one at the atomistic level and one at the coarse-grained level, are usually required (although more can be implemented if desired). This new method can approximately obtain the correct canonical sampling if the exchange interval is sufficiently large to allow the system to explore the local energy landscape. The method is demonstrated for a two-dimensional model system, where the ideal population distribution can be recovered, and also for an alanine polypeptide (Ala15) model with explicit water, where its native structure, an α helix, is obtained from the extended structure within 1ns.
Features of Moyal trajectories
Authors: Dias Nuno Costa , Prata João Nuno
Published: February 2007

We study the Moyal evolution of the canonical position and momentum variables. We compare it with the classical evolution and show that, contrary to what is commonly found in the literature, the two dynamics do not coincide. We prove that this divergence is quite general by studying Hamiltonians of the form p2∕2m+V(q). Several alternative formulations of Moyal dynamics are then suggested. We introduce the concept of star function and use it to reformulate the Moyal equations in terms of a system of ordinary differential equations on the noncommutative Moyal plane. We then use this formulation to study the semiclassical expansion of Moyal trajectories, which is cast in terms of a (order by order in ℏ) recursive hierarchy of (i) first order partial differential equations as well as (ii) systems of first order ordinary differential equations. The latter formulation is derived independently for analytic Hamiltonians as well as for the more general case of locally integrable ones. We present various examples illustrating these results.
Roughness and pore structure control of ordered mesoporous silica films for the enhancement of electrical properties
Authors: Jung Sang-Bae , Ha Tae-Jung , Park Hyung-Ho
Published: February 2007

Mesostructured silica films with a well-ordered Im3m structure and enhanced surface properties can be synthesized by means of cosolvent addition and the optimization of sol aging time. Mesostructured silica films fabricated using ethanol, a commercial solvent, result in wavy surface properties induced by the Marangoni effect irrespective of rotation speed during spin coating. In order to improve the surface roughness, we used an ethanol-acetone mixture as a solvent with a certain molar ratio. Wavy and rough films could be avoided when the acetone molar ratio was optimized. The simultaneous increase of unit cell size and thickness of the film was observed when the amount of cosolvent was increased. The unit cell was also enlarged with sol aging time, and well-ordered mesoporous silica films could be synthesized by controlling the silica sol aging. The dielectric property could be improved by means of cosolvent addition only after the development of a highly ordered mesoporous nature of the film by calcination. The leakage current of the mesoporous silica film could be reduced when the structural ordering and surface roughness were controlled.
Modeling of intermediate phase growth
Authors: Umantsev A.
Published: February 2007

We introduced a continuum method for modeling of intermediate phase growth and numerically simulated three common experimental situations relevant to the physical metallurgy of soldering: growth of intermetallic compound layer from an unlimited amount of liquid and solid solders and growth of the compound from limited amounts of liquid solder. We found qualitative agreements with the experimental regimes of growth in all cases. For instance, the layer expands in both directions with respect to the base line when it grows from solid solder, and grows into the copper phase when the solder is molten. The quantitative agreement with the sharp-interface approximation was also achieved in these cases. In the cases of limited amounts of liquid solder we found the point of turnaround when the compound/solder boundary changed the direction of its motion. Although such behavior had been previously observed experimentally, the simulations revealed important information: the turnaround occurs approximately at the time of complete saturation of solder with copper. This result allows us to conclude that coarsening of the intermetallic compound structure starts only after the solder is practically saturated with copper.
Ionization and dissociation of CH3I in intense laser field
Authors: Liu Hongtao , Yang Zheng , Gao Zhen , Tang Zichao
Published: February 2007

The ionization-dissociation of methyl iodide in intense laser field has been studied using a reflection time-of-flight mass spectrometry (RTOF-MS), at a laser intensity of ⩽6.6×1014W∕cm2, λ=798nm, and a pulse width of 180fs. With the high resolution of RTOF-MS, the fragment ions with the same M∕z but from different dissociation channels are resolved in the mass spectra, and the kinetic energy releases (KERs) of the fragment ions such as Iq+ (q=1–6), CHm+ (m=0–3), C2+, and C3+ are measured. It is found that the KERs of the fragment ions are independent of the laser intensity. The fragments CH3+ and I+ with very low KERs (<1eV for CH3+ and <0.07eV for I+) are assigned to be produced by the multiphoton dissociation of CH3I+. For the fragments CH3+ and I+ from CH3I2+, they are produced by the Coulomb explosion of CH3I2+ with the interaction from the covalent force of the remaining valence electrons. The split of the KER of the fragments produced from CH3I2+ dissociation is observed experimentally and explained with the energy split of I+(P23) and I+(P0,13). The dissociation CH3I3+→CH3++I2+ is caused by Coulomb explosion. The valid charge distance Rc between I2+ and CH3+, at which enhanced ionization of methyl iodide occurs, is obtained to be 3.7Å by the measurements of the KERs of the fragments CH3+ and I2+. For the CH3In+ (n⩾3), the KERs of the fragment ions CH3p+ and Iq+ are attributed to the Coulomb repulsion between CH3p+ and Iq+ from Rc≈3.7Å. The dissociation of the fragment CH3+ is also discussed. By the enhanced ionization mechanism and using the measured KER of Iq+, all the possible Coulomb explosion channels are identified. By comparing the abundance of fragment ions in mass spectrum, it is found that the asymmetric dissociation channels with more charges on iodine, q>p, are the dominant channels.
Manipulating multidimensional electronic spectra of excitons by polarization pulse shaping
Authors: Voronine Dmitri V. , Abramavicius Darius , Mukamel Shaul
Published: February 2007

A simulation study demonstrates how coherent control, combined with adaptive polarization pulse shaping and a genetic algorithm, may be used to simplify femtosecond coherent nonlinear optical signals of excitons. Cross peaks are amplified and resolved, and diagonal peaks are suppressed in the heterodyne-detected two-pulse echo signal from the Soret band of a porphyrin dimer coupled to a Brownian oscillator bath. Various optimization strategies involving the spectral, temporal, and polarization profiles of the second pulse are compared.
Propagation, beam geometry, and detection distortions of peak shapes in two-dimensional Fourier transform spectra
Authors: Yetzbacher Michael K. , Belabas Nadia , Kitney Katherine A. , Jonas David M.
Published: February 2007

Using a solution of Maxwell’s equations in the three-dimensional frequency domain, femtosecond two-dimensional Fourier transform (2DFT) spectra that include distortions due to phase matching, absorption, dispersion, and noncollinear excitation and detection of the signal are calculated for Bloch, Kubo, and Brownian oscillator relaxation models. For sample solutions longer than a wavelength, the resonant propagation distortions are larger than resonant local field distortions by a factor of ∼L∕λ, where L is the sample thickness and λ is the optical wavelength. For the square boxcars geometry, the phase-matching distortion is usually least important, and depends on the dimensionless parameter, Lsin2(β)Δω∕(nc), where β is the half angle between beams, n is the refractive index, c is the speed of light, and Δω is the width of the spectrum. Directional filtering distortions depend on the dimensionless parameter, [(Δω)w0sin(β)∕c]2, where w0 is the beam waist at the focus. Qualitatively, the directional filter discriminates against off diagonal amplitude. Resonant absorption and dispersion can distort 2D spectra by 10% (20%) at a peak optical density of 0.1 (0.2). Complicated distortions of the 2DFT peak shape due to absorption and dispersion can be corrected to within 10% (15%) by simple operations that require knowledge only of the linear optical properties of the sample and the distorted two-dimensional spectrum measured at a peak optical density of up to 0.5 (1).
Effects of annealing on amorphous GdxSi1−x near the metal-insulator transition
Authors: Guillotel E. , Zeng L. , Helgren E. , Hellman F. , Islam R. , Smith David J.
Published: February 2007

Annealing of amorphous Gd–Si films produces large changes in magnetic and magnetotransport properties. The materials have spin-glass freezing and enormous negative magnetoresistance (MR) in the unannealed state but show drastically reduced MR and magnetization on annealing. These changes can be explained by high resolution transmission electron micrographs and energy-dispersive x-ray analysis which show the appearance of nanocrystalline clusters of GdSi and GdSi2 in an amorphous background. A comparison with the nonmagnetic analog Y–Si shows similar modification of electrical properties.
A study of trench-edge defect formation in (001) and (011) silicon recrystallized by solid phase epitaxy
Authors: Saenger K. L. , de Souza J. P. , Fogel K. E. , Ott J. A. , Sung C. Y. , Sadana D. K. , Yin H.
Published: February 2007

Trench-edge defects formed during epitaxial recrystallization of trench-bounded amorphized silicon (a-Si) regions are examined as a function of Si substrate crystal orientation. In Si (001), rectilinear a-Si features having edges aligned with the crystal’s in-plane ⟨110⟩ directions recrystallize leaving trench-edge defects along all trench edges, whereas the identical features in Si (011) recrystallize without trench-edge defects along trench edges parallel to the crystal’s in-plane ⟨100⟩ direction and with trench-edge defects along trench edges parallel to the crystal’s in-plane ⟨110⟩ direction. The positions and lateral extent of these trench-edge defects suggest that their source is defective epitaxy on slow-growing {111} planes formed during recrystallization. A heuristic model proposed to explain the formation of these {111} planes correctly predicts the essentially defect-free recrystallization seen for rectilinear a-Si features in Si (001) having edges aligned with the crystal’s in-plane ⟨100⟩ directions, but cannot completely account for the distinctively curved growth fronts sometimes seen at intermediate stages of recrystallization.
Diagnosis of transient electrokinetic flow in microfluidic channels
Authors: Yan Deguang , Yang Chun , Nguyen Nam-Trung , Huang Xiaoyang
Published: February 2007

Measuring the electro-osmotic velocity distributions in microchannels is usually performed for steady-state electrokinetic flows. Characterizing time-dependent electrokinetic flows is of importance to the development of microfluidic devices such as rapid capillary electrophoretic separation system, ac pumps, novel micromixers, etc. In this paper, we use a micron-resolution particle image velocimetry (micro-PIV) based phase locking technique with an ordinary PIV charge coupled device (CCD) camera to carry out an experimental study of the transient electrokinetic flow in microchannels by synchronizing different trigger signals for the laser, CCD camera, and in-house designed high-voltage switch. With the transient micro-PIV technique, we further propose a method to decouple the particle electrophoretic velocity from the micro-PIV measured velocity and to determine the zeta potential of the channel wall. The time evolution of the full-field, electro-osmotic velocity distributions in both open- and closed-end rectangular microchannels is obtained. Using the slip velocity approach and the measured channel zeta potential, the theoretical predictions of the transient electro-osmotic flow in the open- and closed-end microchannels are obtained, and they are found to be in good agreement with the experimental results.
Electronic absorption spectra of the protonated polyacetylenes HC2nH2+ (n=3,4) in the gas phase
Authors: Dzhonson Anatoly , Jochnowitz Evan B. , Kim Eunsook , Maier John P.
Published: February 2007

A new approach has been developed for the purpose of measuring the electronic transitions to bound exited states for cations that have been collisionally relaxed to low vibrational and rotational temperatures. This has been used to obtain the first gas phase electronic spectra of the protonated polyacetylenes using a two-color ion-photodissociation approach. Specifically, the origin bands in the BA11←XA11 transitions of HC6H2+ and HC8H2+ (C2v geometry) were observed at 26 403.3 and 21399.8cm−1. Data on such cooled systems allow a direct comparison between laboratory and astrophysical measurements.
Multiphase coexistence in polydisperse colloidal mixtures
Authors: Grodon C. , Roth R.
Published: February 2007

The authors study the phase behavior of mixtures of monodisperse colloidal spheres with a depletion agent which can have arbitrary shape and can possess a polydisperse size or shape distribution. In the low concentration limit considered here, the authors can employ the free-volume theory and take the geometry of particles of the depletion agent into account within the framework of fundamental measure theory. The authors apply their approach to study the phase diagram of a mixture of (monodisperse) colloidal spheres and two polydisperse polymer components. By fine tuning the distribution of the polymer, it is possible to construct a complex phase diagram which exhibits two stable critical points.
Statistical properties and kinetics of end-end contact formation of unfolded polypeptides: A systematic molecular dynamics study
Authors: Ping Guanghui , Dastidar Shubhra Ghosh , Duan Yong
Published: February 2007

The authors have systematically examined the statistical properties of the unfolded states of series of polypeptides and the kinetics of their end-to-end contact (ring closure) formation by molecular dynamics simulations. The formation of an end-to-end contact follows a single-exponential decay as measured by the first-passage time. It is shown that the shifted Gaussian chain model can be applied to describe the dimensions of glycine-rich polypeptides at high temperature. However, notable deviation from the ideal Gaussian chain model was observed at lower temperatures particularly for those polypeptides without glycines, due to the tendency to form local structures.
High-accuracy calculation of nuclear quadrupole moments of atomic halogens
Authors: Yakobi Hana , Eliav Ephraim , Visscher Lucas , Kaldor Uzi
Published: February 2007

Electric field gradients at the nuclei of halogen atoms are calculated using a finite field approach. The four-component Dirac-Coulomb Hamiltonian serves as the framework, all electrons are correlated by the relativistic Fock-space coupled cluster method with single and double excitations, and the Gaunt term, the main part of the Breit interaction, is included. Large basis sets (e.g., 28s24p21d9f4g2h Gaussian-type functions for I) are used. Combined with experimental nuclear quadrupole coupling constants, accurate estimates of the nuclear quadrupole moments are obtained. The calculated values are Q(Cl35)=−81.1(1.2)mb, Q(Br79)=302(5)mb, and Q(I127)=−680(10)mb. Currently accepted reference values [Pyykkö, Mol. Phys. 99, 1617 (2001)] are −81.65(80), 313(3), and −710(10)mb, respectively. Our values are lower for the heavier halogens, corroborating the recent work of van Stralen and Visscher [Mol. Phys. 101, 2115 (2003)], who obtained Q(I127)=−696(12)mb in a series of molecular calculations.
High temperature investigation of the magnetization behavior in cobalt substituted ZnO
Authors: Bhatti Kanwal Preet , Chaudhary Sujeet , Pandya Dinesh K. , Kashyap Subhash C.
Published: February 2007

High temperature magnetization studies (up to 650°C) of the chemically synthesized nanocrystalline Zn0.9Co0.1O samples are reported in this paper. A systematic study of sequentially sintered sample has been carried out to correlate the observed changes in magnetic behavior vis à vis very small changes in the unit-cell dimensions, evolution of cobalt oxide phases, and absence of Co clusters. The Curie temperature of cobalt substituted ZnO is determined to be ∼495°C. A plausible explanation of the observed room temperature ferromagnetism is presented in terms of bound magnetic polarons model.
Simulation of slowly dragging a cylinder through a confined pressurized bed of granular materials using the discrete element method
Authors: Zhou Fuping , Advani Suresh G. , Wetzel Eric D.
Published: February 2007

A nonlinear spring dash pot model to describe the interaction forces between confined granules under high pressures based on Hertz contact theory is proposed. The discrete element method (DEM) is used to simulate the movement and calculate the normal and tangential contact forces among the granules when a cylinder is dragged through a granular bed at low velocities. The time-dependent, total drag force required to pull the circular cylinder is also calculated and used to compare the effect of material and boundary conditions on flow behavior. Simulation results show that drag force increases with cylinder diameter, granular volume fraction, granular size, and the friction coefficient between granules. Drag force was found to be independent of the velocity of the cylinder at low speed, the friction coefficient between the granules and the cylinder, and the friction coefficient between the granules and the container walls.
Isotopically selective collisional vibrational energy transfer in CF3H
Authors: Bossart R. , Boyarkin O. V. , Makarov A. A. , Rizzo T. R.
Published: February 2007

The authors investigate here the mechanism of collisionally enhanced isotopic selectivity observed in infrared multiple photon dissociation (IRMPD) of vibrationally preexcited CF3H by Boyarkin et al. [J. Chem. Phys. 118, 93 (2003)]. For both the carbon-12 and carbon-13 isotopic species they measure the dependence of the IRMPD yield on the time delay between the preexcitation and the dissociation pulses at different dissociation frequencies as well as its dependence on the initial isotopic composition of the sample. The results reveal that the collisional increase in isotopic selectivity originates not only from that of IRMPD itself but also from the isotopic selectivity of vibrational energy transfer, with the latter making the major contribution under their experimental conditions. They suggest that the observed isotopic selectivity in collisional energy transfer arises from the difference in overlap between the absorption spectra of the ν5 mode in the C12F3H acceptor molecule with emission spectra of the same mode in the two isotopically different donors. Understanding the origin of this collisional effect has important implications for optimization of laser isotope separation processes.
Generalized non-Markovian optical Bloch equations
Authors: Budini Adrián A.
Published: February 2007

By considering single chromophore systems whose radiative decay can be written in terms of a nonlocal Lindblad-type evolution, the authors extend the formalism of generalized optical Bloch equations [Y. Zheng and F. L. H. Brown, Phys. Rev. Lett. 90, 238305 (2003)] to non-Markovian dynamics. They demonstrate that photon statistical properties such as bunching and antibunching, as well as sub- and super-Poissonian photon statistics can be fitted in the context of non-Markovian dynamics. The nonlocal effects may arise due to the interaction with a complex structured environment. In this case, the photon statistics can be related with the parameters that define the microscopic system-environment interaction. Alternatively, the authors demonstrate that effective dynamics such as triplet blinking, where the system is coupled via incoherent transitions to an extra dark state, can also be worked out in terms of generalized non-Markovian optical Bloch equations. The corresponding memory contributions are mapped with those that arise from the microscopic approach.
A criterion for pure pair-ion plasmas and the role of quasineutrality in nonlinear dynamics
Authors: Saleem H.
Published: February 2007

A criterion is presented to decide whether a produced plasma can be called a pure pair-ion plasma or not. The theory is discussed in the light of recent experiments which claim that a pure pair-ion fullerene (C60±) plasma has been produced. It is also shown that the ion acoustic wave is replaced by the pair ion convective cell (PPCC) mode as the electron density becomes vanishingly small in a magnetized plasma comprised of positive and negative ions. The nonlinear dynamics of pure pair plasmas is described by two coupled equations which have no analog in electron-ion plasmas. In a stationary frame, it becomes similar to the Hasegawa-Mima equation but does not contain drift waves and ion acoustic waves.
Hole spin relaxation in neutral InGaAs quantum dots: Decay to dark states
Authors: Hall K. C. , Koerperick E. J. , Boggess Thomas F. , Shchekin O. B. , Deppe D. G.
Published: February 2007

The authors report measurements of hole spin relaxation in neutral InGaAs quantum dots using polarization-dependent time-resolved photoluminescence experiments. The single-particle hole spin relaxation was isolated from other spin flip processes in the electron-hole system by detecting the initial transfer of population from optically active to dark states. The results indicate that electron-hole exchange interactions play a negligible role in the carrier spin kinetics, and are consistent with a mechanism of hole spin relaxation via phonon-mediated virtual scattering between confined quantum dot states.
The Conversion of Ethyl Dienol Ether and Dienyl Pivalate Derivatives of Hagemanns Ester Into Bicyclic Enones
Authors: Baker MV , Ghitgas C , Dancer RJ , Haynes RK , Sherwood GV
Published: February 2007

The cyclization of compounds obtained from ethyl dienol ether and dienyl pivalate derivatives of Hagemann's ester has been examined. The carbanions of methyl phenyl sulfone and methyl phenyl sulfoxide react with the methylated dienol ether (4) to give the β-keto sulfone (8) and sulfoxide (9), the former of which was converted into the oxabicyclo[4.3.0]non-1-en-3-one (16). The iodide (17) with potassium t-butoxide in t-butyl alcohol gave the octahydronaphthalenone (18). With lithium ethoxide in tetrahydrofuran the octahydronaphthalenedione (22) was obtained from the dienyl pivalate (24). Both reactions involve the generation and intramolecular cyclization of a dienolate produced by cleavage of the pivaloyl group in each of (17) and (24). The scope and limitations of these reactions are briefly discussed.
The Structures of Mono and Bis β-Diketonate Tin(IV) Alkoxide Complexes
Authors: Chandler CD , Fallon GD , Koplick AJ , West BO
Published: February 2007

Tin(IV) alkoxides react with pentane-2,4-dione (acetylacetone) and other β-diketones to yield Sn(OR)3(chel) or Sn(OR)2(chel)2 derivatives. Sn(Opri)3(acac) has been shown to be dimeric in the solid state by a single-crystal X-ray diffraction study, the tin atoms being linked by two alkoxide bridges. In solution l19sn n.m.r. spectral data show that this single complex rapidly converts into a mixture of tin-containing species followed by slow disproportionation to the bis derivative Sn(OPri)2(acac)2 and Sn(Opri)4. The bis complexes Sn(OR)2(acac)2 appear to exist predominantly in solution with cis arrangements of alkoxide groups even when OBut or 2,2,6,6-tetramethylheptane-3,5-dione
(dipivaloylmethane) are present.
Interpretation of Bond Angles in Some Hydride Molecules
Authors: Nordholm S
Published: February 2007

The dependence of the bond angles in the molecules XH2 and YH3 (X = O, S, Se and Y = N, P, As ) and related iso electronic molecular ions upon the mass of the central atom is examined. Calculations of optimized geometries are carried out by using Hartree-Fock theory and double-zeta basis sets. The results are compared with experimental and accurate computational results in order to investigate the applicability of simple valence shell electron pair repulsion and valence bond rules for geometry prediction. Particular attention is given to the valence bond picture of the effect of the size of the central atom.
Imidazo[1,2-B]pyridazines. II. 6-Alkylthio and 6-Arylthio-3-methoxy-2-phenylimidazo[1,2-b]pyridazines
Authors: Barlin GB , Ireland SJ
Published: February 2007

A series of 6-alkylthio- and 6-arylthio-3-methoxy-2-phenylimidazo[l,2- b]pyridazines has been prepared from 6-alkylthio-and 6-arylthio-pyridazin-3-amines through the corresponding 6-alkylthio-and 6-arylthio-2-phenylimidazo[l,2-b] pyridazin-3(5H)-ones.
Lack of myostatin results in excessive muscle growth but impaired force generation
Authors: Amthor Helge , Macharia Raymond , Navarrete Roberto , Schuelke Markus , Brown Susan C. , Otto Anthony , Voit Thomas , Muntoni Francesco , Vrbóva Gerta , Partridge Terence , Zammit Peter , Bunger Lutz , Patel Ketan
Published: February 2007

The lack of myostatin promotes growth of skeletal muscle, and blockade of its activity has been proposed as a treatment for various muscle-wasting disorders. Here, we have examined two independent mouse lines that harbor mutations in the myostatin gene, constitutive null (
Mstn
−/−
) and compact (Berlin High Line,
BEH
c/c
). We report that, despite a larger muscle mass relative to age-matched wild types, there was no increase in maximum tetanic force generation, but that when expressed as a function of muscle size (specific force), muscles of myostatin-deficient mice were weaker than wild-type muscles. In addition,
Mstn
−/−
muscle contracted and relaxed faster during a single twitch and had a marked increase in the number of type IIb fibers relative to wild-type controls. This change was also accompanied by a significant increase in type IIB fibers containing tubular aggregates. Moreover, the ratio of mitochondrial DNA to nuclear DNA and mitochondria number were decreased in myostatin-deficient muscle, suggesting a mitochondrial depletion. Overall, our results suggest that lack of myostatin compromises force production in association with loss of oxidative characteristics of skeletal muscle.
Knowledge, Practice, and Attitude Among Iranian Nurses, Midwives, and Students Regarding Standard Isolation Precautions
Authors: Askarian Mehrdad , Memish Ziad A. , Khan Ashraf A.
Published: February 2007

Our goal was to assess the knowledge, attitudes, and practices regarding infection control and standard precautions among a group of nursing and midwifery instructors and students in Iran. A survey questionnaire was completed by 273 nursing and midwifery instructors and students at Shiraz University Medical Sciences during the period from May to November 2002. Two hundred thirty-one (90.9%) of the participants reported that they needed additional infection control education, especially on standard isolation precautions. There was a linear positive correlation between knowledge, practice, and attitude scores for the group of nursing, auxiliary nursing, and midwifery instructors, as well as their students (P < .05). Our study shows that there is an urgent need for evaluating education on infection control practices and standard precautions in general, as well as for structured infection control programs among nursing and midwifery staff.
Use of Hypochlorite Solution to Decrease Rates of Clostridium difficile-Associated Diarrhea
Authors: McMullen Kathleen M. , Zack Jeanne , Coopersmith Craig M. , Kollef Marin , Dubberke Erik , Warren David K.
Published: February 2007

An increased rate of Clostridium difficile-associated diarrhea (CDAD) was noted in 2 intensive care units of a university-affiliated tertiary care facility. One unit instituted enhanced environmental cleaning with a hypochlorite solution in all rooms, whereas the other unit used hypochlorite solution only in rooms of patients with CDAD. The CDAD rates decreased in both units.
Trace class criteria for bilinear Hankel forms of higher weights
Authors: Sundhäll Marcus
Published: February 2007

In this paper we give a complete characterization of higher weight Hankel forms, on the unit ball of

C

d

\mathbb {C}^d

, of Schatten-von Neumann class

S

p

\mathcal {S}_p

,

1
≤
p
≤
∞

1\leq p\leq \infty

. For this purpose we give an atomic decomposition for certain Besov-type spaces. The main result is then obtained by combining the decomposition and our earlier results.
Forcing a mutual stationarity property in cofinality 𝜔₁
Authors: Koepke Peter
Published: February 2007

We show that the consistency strength, relative to the system

ZFC
\operatorname {ZFC}

, of the mutual stationarity property

MS
⁡
(

ℵ
3

,

ℵ
5

,

ℵ
7

,
…
;

ω
1

)

\operatorname {MS} (\aleph _3,\aleph _5, \aleph _7, \ldots ; \omega _1 )

is equal to the existence of one measurable cardinal. We also discuss mutual stationarity for some other configurations of small cardinal parameters.
Tornado solutions for semilinear elliptic equations in ℝ²: regularity
Authors: Meadows Alexander
Published: February 2007

We give conditions under which bounded solutions to semilinear elliptic equations

Δ
u
=
f
(
u
)

\Delta u = f(u)

on domains of

R

2

\mathbb {R}^2

are continuous despite a possible infinite singularity of

f
(
u
)

f(u)

. The conditions do not require a minimization or variational stability property for the solutions. The results are used in a second paper to show regularity for a familiar class of equations.
Tornado solutions for semilinear elliptic equations in ℝ²: Applications
Authors: Hammock Frances , Luthy Peter , Meadows Alexander , Whitman Phillip
Published: February 2007

We show partial regularity of bounded positive solutions of some semilinear elliptic equations

Δ
u
=
f
(
u
)

\Delta u = f(u)

in domains of

R

2

\mathbb {R}^2

. As a consequence, there exists a large variety of nonnegative singular solutions to these equations. These equations have previously been studied from the point of view of free boundary problems, where solutions additionally are stable for a variational problem, which we do not assume.
Powers and roots of Toeplitz operators
Authors: Louhichi Issam
Published: February 2007

We study the commutativity of two Toeplitz operators whose symbols are quasihomogeneous functions. We give a relationship between this commutativity and the roots (or powers) of the Toeplitz operators. We use this to characterize Toeplitz operators with symbols in

L

∞

(

D

)

L^{\infty }(\mathbb {D})

which commute with Toeplitz operators whose symbols are of the form

e

i
p
θ

r
m

e^{ip\theta }r^m

.
Equivariant crystalline cohomology and base change
Authors: Grosse-Klönne Elmar
Published: February 2007

Given a perfect field

k
k

of characteristic

p
>
0

p>0

, a smooth proper

k
k

-scheme

Y
Y

, a crystal

E
E

on

Y
Y

relative to

W
(
k
)

W(k)

and a finite group

G
G

acting on

Y
Y

and

E
E

, we show that, viewed as a virtual

k
[
G
]

k[G]

-module, the reduction modulo

p
p

of the crystalline cohomology of

E
E

is the de Rham cohomology of

E
E

modulo

p
p

. On the way we prove a base change theorem for the virtual

G
G

-representations associated with

G
G

-equivariant objects in the derived category of

W
(
k
)

W(k)

-modules.
Geometric cohomology frames on Hausmann–Holm–Puppe conjugation spaces
Authors: van Hamel Joost
Published: February 2007

For certain manifolds with an involution the mod 2 cohomology ring of the set of fixed points is isomorphic to the cohomology ring of the manifold, up to dividing the degrees by two. Examples include complex projective spaces and Grassmannians with the standard antiholomorphic involution (with real projective spaces and Grassmannians as fixed point sets). Hausmann, Holm and Puppe have put this observation in the framework of equivariant cohomology, and come up with the concept of conjugation spaces, where the ring homomorphisms arise naturally from the existence of what they call cohomology frames. Much earlier, Borel and Haefliger had studied the degree-halving isomorphism between the cohomology rings of complex and real projective spaces and Grassmannians using the theory of complex and real analytic cycles and cycle maps into cohomology. The main result in the present note gives a (purely topological) connection between these two results and provides a geometric intuition into the concept of a cohomology frame. In particular, we see that if every cohomology class on a manifold

X
X

with involution is the Thom class of an equivariant topological cycle of codimension twice the codimension of its fixed points (inside the fixed point set of

X
X

), these topological cycles will give rise to a cohomology frame.
On the finiteness properties of extension and torsion functors of local cohomology modules
Authors: Khashyarmanesh Kazem
Published: February 2007

Let

R
R

be a commutative Noetherian ring with non-zero identity,

a

\mathfrak {a}

and

b

\mathfrak {b}

ideals of

R
R

with

a

⊆

b

\mathfrak {a} \subseteq \mathfrak {b}

, and

M
M

a finitely generated

R
R

-module. In this paper, for fixed integers

j
j

and

n
n

, we study the finiteness of

Ext
R
j

⁡
(
R

/

b

,

H

a

n

(
M
)
)

\operatorname {Ext}^j_R(R/\mathfrak {b},H^n_{\mathfrak {a}}(M))

and

T
o

r
j
R

(
R

/

b

,

H

a

n

(
M
)
)

Tor_j^R(R/\mathfrak {b},H^n_{\mathfrak {a}}(M))

in several cases.
On uniformly Gâteaux smooth norms and normal structure
Authors: Johanis Michal , Rychtář Jan
Published: February 2007

It is shown that every separable Banach space admits an equivalent norm that is uniformly Gâteaux smooth and yet lacks asymptotic normal structure.
New proof of the Hörmander multiplier theorem on compact manifolds without boundary
Authors: Xu Xiangjin
Published: February 2007

On compact manifolds

(
M
,
g
)

(M, g)

without boundary, the gradient estimates for unit band spectral projection operators

χ

λ

\chi _{\lambda }

are proved for a second order elliptic differential operator

L
L

. A new proof of the Hörmander Multiplier Theorem (first proved by A. Seeger and C.D. Sogge in 1989) is given in this setting by using the gradient estimates and the Calderón-Zygmund argument.
Exponential growth of Lie algebras of finite global dimension
Authors: Felix Yves , Halperin Steve , Thomas Jean-Claude
Published: February 2007

Let

L
L

be a connected finite type graded Lie algebra. If dim

L
=
∞

L = \infty

and gldim

L
>
∞

\, L>\infty

, then log index

L
=
α
>
0

\, L=\alpha >0

. If, moreover,

α
>
∞

\alpha >\infty

, then for some

d
d

,
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="sigma-summation Underscript i equals 1 Overscript d minus 1 Endscripts reverse-solidus textrm left-brace dimension right-brace upper L Subscript k plus i Baseline equals e Superscript k alpha Super Subscript k Superscript Baseline comma">

∑

i
=
1

d
−
1

\textrm {dim}

L

k
+
i

=

e

k

α
k

,

\sum _{i=1}^{d-1} \mbox {\textrm {dim}}\, L_{k+i} = e^{k\alpha _k}\,,\,\,

where

α
k

→

\alpha _k \to

log index

L
L

as

k
→
∞

.

k\to \infty \,.
Natural Philosophy
Authors: Cullen Christopher M.
Published: February 2007

According to Bonaventure, metaphysics, as a branch of natural philosophy, is concerned with the truth of “things”. But unlike physics, which investigates things insofar as they change, metaphysics goes beyond motion and quantity to investigate things simply insofar as they exist or are “beings”. This investigation involves reducing things back to the most fundamental concept, namely, being. It has three main parts: (1) how things came to be from the First Principle, that is, why there is something rather than nothing; (2) how things reflect ideas or “exemplars” in the divine mind, in other words, how things are what they are and are intelligible; and finally, (3) how things “return” to their source, or, the ultimate meaning of things. These three aspects constitute the three parts of metaphysics: emanation, exemplarism, and consummation.
The Creation of the World
Authors: Cullen Christopher M.
Published: February 2007

This chapter explores why Bonaventure explicitly includes creation as a distinct subject area in his division of theology and what theology adds to the understanding of creation. Bonaventure believes that theology reinforces our awareness of the nothingness of creation. Recalling this means that Bonaventure's doctrine of creation can be understood. In considering this doctrine, however, it is also important to keep in mind that Bonaventure believes creation ex nihilo (from nothing) can be known by reason alone.
Grace
Authors: Cullen Christopher M.
Published: February 2007

Bonaventure distinguishes three meanings for grace. First, in a general sense, it is the assistance freely and liberally granted by God to creatures performing any of their acts. Second, in a more proper sense, grace (gratia) is a term usually reserved for the gift from God by which the human soul is perfected and transformed. Third, is the concept of created sense as the means of justification and of this justification involving a change in being.
The Sacramental Cure
Authors: Cullen Christopher M.
Published: February 2007

Bonaventure uses “sacrament” to refer to all signs of faith in the Redeemer, even those that are not explicitly focused on Jesus of Nazareth. He refers to this as the “diversity” of the sacraments. “Sacraments” in this sense were instituted from the very beginning, but they have enjoyed diversity through three different ages and their concomitant laws: the law of nature, the law of scripture, and the law of grace.
Introduction
Authors: Waghorne Joanne Punzo
Published: February 2007

Tourists rarely consider Chennai a “temple city”, yet this major commercial center is experiencing a temple building boom. As active in building the economy as in constructing temple, new donors and devotees, who openly describe themselves as “middle class”, hold responsible positions in Chennai's modern technological, scientific, governmental, and business establishments. This chapter introduces the array of temples surveyed in Chennai and the many rituals of consecration (mahakumbhabhisheka) observed. Highlighting three new temples and their urban donors in detail, the chapter reconsiders “religion in the city”/urban religion (post Max Weber); the interplay of “tradition” and “modernity” (post Milton Singer); and old issues of economic development and Hindu religiosity. The chapter argues that significant cultural-religious changes occur in these temples, where donors and devotees reconstruct “tradition” and establish innovations in the context of space not ideology, thus creating an emerging reconfiguration of Hinduism that both rivals and parallels the much-discussed Hindu nationalism.
The Gentrification of the Goddess
Authors: Waghorne Joanne Punzo
Published: February 2007

Encircled by ever-expanding suburbs of Chennai, many old village “seats” of feminine divine power (shakti pitha) are attracting ardent new middle-class devotees. Called Amman (mother) in Tamil, these Goddesses (Mariyamman, Mundakakkanni Amman, Kolavizhi Amman) reign alone, usually without a male consort. Middle-class neighborhood groups, often led by women, are taming the powers of such “village” goddesses long associated with blood sacrifices and wild ecstasy by giving these Goddesses inviting faces and literally “domesticating” their sites into proper new temples. This process of gentrification or “bourgeoisification” of the Goddess reveals evolving middle-class religious sensibilities. Goddess temples become the sites for a new bourgeois public sphere (Habermas), where the middle classes enact and construct a common identity. This gentrification reaches out into the surrounding streets as well, where new groups lobby for public cleanliness. A sign on the wall of an old temple reads “Please help us keep the street clean”.
The Architecture of Reason
Authors: Audi Robert
Published: February 2007

The literature on theoretical reason has been dominated by epistemological concerns, treatments of practical reason by ethical concerns. This book overcomes the limitations of dealing with each separately. It sets out a comprehensive theory of rationality applicable to both practical and theoretical reason. In both domains, the book explains how experience grounds rationality, delineates the structure of central elements, and attacks the egocentric conception of rationality. It establishes the rationality of altruism and thereby supports major moral principles. The concluding part describes the pluralism and relativity the book's conception of rationality accommodates and, taking the unified account of theoretical and practical rationality in that light, constructs a theory of global rationality — the overall rationality of persons.
Saadiah Gaon
Authors: Eisen Robert
Published: February 2007

This analysis of Saadiah’s reading of Job begins with a brief summary of his discussion of the suffering of the righteous in Beliefs and Opinions, where he lays out the philosophical ideas that are critical for his interpretation of Job. This is followed by a summary of the contents of his commentary on Job. The discussion then proceeds in the order of the three interfaces outlined in the introduction: a discussion of the sources and antecedents of Saadiah’s reading of the Book of Job; an analysis of Saadiah’s reading as an exegetical exercise grappling with the biblical text; and finally revisiting Saadiah’s discussion of the suffering of the righteous in Beliefs and Opinions to determine precisely how his systematic thinking on theodicy relates to his exegesis on Job.
So This Is What It's Like
Authors: Nemirow Laurence
Published: February 2007

This chapter focuses on the objective grounds for and against the ability hypothesis (AH), which was developed as a response to the Knowledge Argument (KA) — a purported proof of the existence of “phenomenal information”. It argues that while KA capitalizes on the mysticism inspired by “So this is what it's like” and embraces the existence of propositional knowledge that cannot be put into words, AH provides a more worldly account that explains both the cognitive role of knowing what it's like and its essential connection with firsthand experience. This approach engenders almost religious objection. But the test of a philosophical theory is not the fervor of the criticism it engenders, but the strength of the available rejoinders; and AH proves to be reasonably resilient to assault.
What Is This Thing You Call Color
Authors: Nordby Knut
Published: February 2007

The late Knut Nordby was a real-life counterpart of Mary: a color-blind expert in the science of color vision. This chapter describes the results of empirical research on color vision and other sense modalities. Based on these results and his own experience, he argues that Mary will be able to sense and discriminate color hues, but will not be able to name them on the basis of her knowledge. He does not take a definite stand on the epistemic and metaphysical gaps. But his reflections should help inform views on these matters.
What Is a Phenomenal Concept?
Authors: Levin Janet
Published: February 2007

This chapter presents a version of the phenomenal concept strategy based on a limited defense of the “demonstrative account” of phenomenal concepts. In this account, phenomenal concepts pick out their referents directly, much like demonstratives, without mediation by any mode of presentation. It is argued that this shows that many type-B materialists appeal to this account to help explain why there is an epistemic gap but no metaphysical gap, and that the account can meet objections present elsewhere. It is further argued that recent emendations to the account, including those by Katalin Balog, Block, Papineau, and Levine, concede too much to the antiphysicalists while accomplishing too little. Demonstrative theorists are urged to return to their roots.