Measurement of the mass difference between top and antitop quarks

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

On the orbits of the outer satellites of Jupiter

In this work we study the basic aspects concerning the stability of the outer satellites of Jupiter. Including the effects of the four giant planets and the Sun we study a large grid of initial conditions. Some important regions where satellites cannot survive are found. Basically these regions are due to Kozai and other resonances. We give an analytical explanation for the libration of the pericenters (ω) over bar - (ω) over bar (J). Another different center is also found. The period and amplitude of these librations are quite sensitive to initial conditions, so that precise observational data are needed for Pasiphae and Sinope. The effect of Jupiter's mass variation is briefly presented. This effect can be responsible for satellite capture and also for locking (ω) over bar - (ω) over bar (J) in temporary libration.

Magnetic properties of poly(3-hexylthiophene)

A room temperature ferromagnetic phase is observed in samples of poly(3-hexylthiophene) partially doped with ClO (4) over bar. The magnetic behavior presents a strong dependence on the sample preparation conditions, in particular, a dependence with the final potential of the sample after reduction. The origin of the ferromagnetism is proposed to be associated with interactions between spin 1/2 polarons formed in the polymeric chain upon doping. The dependence of saturation and spontaneous magnetization as the function of the final potential after reduction shows a way to control the magnetic properties of this polymer. (C) 2008 Elsevier B.V. All rights reserved.

Crystal Structure Determination of Mebendazole Form A Using High-Resolution Synchrotron X-Ray Powder Diffraction Data

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

The amphibian tree of life

The evidentiary basis of the currently accepted classification of living amphibians is discussed and shown not to warrant the degree of authority conferred on it by use and tradition. A new taxonomy of living amphibians is proposed to correct the deficiencies of the old one. This new taxonomy is based on the largest phylogenetic analysis of living Amphibia so far accomplished. We combined the comparative anatomical character evidence of Haas (2003) with DNA sequences from the mitochondrial transcription unit HI (12S and 16S ribosomal RNA and tRNA(Valine) genes, 2,400 bp of mitochondrial sequences) and the nuclear genes histone H3, rhodopsin, tyrosinase, and seven in absentia, and the large ribosomal subunit 28S (approximate to 2,300 bp of nuclear sequences; ca. 1.8 million base pairs; x ($) over bar = 3.7 kb/terminal). The dataset includes 532 terminals sampled from 522 species representative of the global diversity of amphibians as well as seven of the closest living relatives of amphibians for outgroup comparisons.

REACTIONS OF MERCURIC ACETATE WITH PENTACARBONYLIRON IN ALCOHOLS - CRYSTAL AND MOLECULAR-STRUCTURES OF HG[FE(COOR)(CO)(4)](2) (R=CH3, C2H5)

Reactions of Hg(CH3COO)(2) with [Fe(CO)(5)] in MeOH and EtOH lead to the compounds Hg[Fe(COOR)(CO)(4)](2) (I for R = CH3 and II for R = C2H5). Crystals of I are triclinic, P (1) over bar, with a = 6.272(2), b = 6.441(3), c = 11.703(4) Angstrom, a = 92.94(3)degrees, beta = 103.77(3)degrees, gamma = 96.10(2)degrees, and Z = 1. Crystals of II are tetragonal, I4(1)/a, with a = 17.906(3) Angstrom, c = 12.756(2) Angstrom, and Z = 8. The geometry around Hg is linear for compound I and approximately linear for compound II. The Hg-Fe distances are 2.5716(8) and 2.575(4) Angstrom for compounds I and II, respectively. The geometry around the Fe in both compounds is approximately octahedral. The carboalkoxy group is cis to Hg in both compounds with Fe-C distances equal to 2.034(6) and 2.05(4) Angstrom for compounds I and II, respectively.

Crystal structure of bis(acetylacetonato)bis(quinoline)nickel(II), Ni(C5H14O2N)(2)(C9H7N)(2)

C28H28N2NiO4, triclinic, P (1) over bar (no. 2), a = 7.9202(6) angstrom, b = 8.0496(6) angstrom, c = 10.246(1) angstrom, alpha = 97.15(1)degrees, beta = 106.68(1)degrees, gamma = 94.686(9)degrees, V = 616.1 angstrom(3), Z = 1, R-gt(F) = 0.028, wR(ref)(F-2) = 0.078, T = 293 K.

Local Er(III) environment in luminescent titanosilicates prepared from microporous precursors

The local environment of Er3+ ions in microporous titanosilicate ETS-10 and in synthetic narsarsukite and glassy materials obtained by calcination of ETS-10 has been investigated by EXAFS, Raman and photoluminescence spectroscopies. Er L-III-edge EXAFS studies of Er3+-doped ETS-10 support the view that the exchanged Er3+ ions reside close to the (negatively charged) TiO6 octahedra. In ETS-10, Er3+ is partially bonded to framework oxygen atoms and hydration water molecules. The Er...Ti distance (3.3 Angstrom) is similar to the Na...Ti distances (3.15-3.20 Angstrom) reported previously for Na-ETS-10. Although the exact location of the ErO6 units within the host structure of Er3+-doped synthetic narsarsukite is still an open question, it is most likely that Er3+ substitutes Ti4+ rather than Na+ ions. EXAFS spectroscopy indicates that no significant clustering of erbium atoms occurs in the titanosilicate samples studied. Evidence for the insertion of Er3+ ions in the framework of narsarsukite has been obtained by Raman spectroscopy. This is indicated by the increasing full-width at half-maximum (FWHM) of the 775 cm(-1) peak and the increasing intensity of the anatase peaks as the erbium content increases. In addition, as the narsarsukite Er3+ content increases a band at ca. 515 cm(-1) firstly broadens and subsequently a new peak appears at ca. 507 cm(-1).Er3+-doped narsarsukite exhibits a characteristic local vibrational frequency, (h) over bar omega ca. 330 cm(-1), with an electron-phonon coupling, g ca. 0.2, which constitutes additional evidence for framework Er3+ insertion. The number of lines in the infrared emission spectrum of synthetic narsarsukite indicates the presence of two optically-active erbium centres with very similar local environments and an average I-4(13/2) lifetime of 7.8 +/- 0.2 ms.

Crystal structure of potassium trifluoro(2-methyl-1,3-dithiano)borate, K(C5H9BF3S2)

C5H9BF3KS2, triclinic, P (1) over bar (no. 2), a = 11.9238(5) angstrom, b = 13.6060(5) angstrom, c = 14.0280(3) angstrom, alpha = 114.995(2)degrees, beta = 92.035(2)degrees, gamma = 92.390(2)degrees, V = 2057.4 angstrom(3), Z = 8, R-gt(F) = 0.049, wR(ref)(F-2) = 0.117, T = 296 K.

An adaptive chart for monitoring the process mean and variance

Traditionally, an (X) over bar chart is used to control the process mean and an R chart is used to control the process variance. However, these charts are not sensitive to small changes in the process parameters. The adaptive ($) over bar and R charts might be considered if the aim is to detect small disturbances. Due to the statistical character of the joint (X) over bar and R charts with fixed or adaptive parameters, they are not reliable in identifing the nature of the disturbance, whether it is one that shifts the process mean, increases the process variance, or leads to a combination of both effects. In practice, the speed with which the control charts detect process changes may be more important than their ability in identifying the nature of the change. Under these circumstances, it seems to be advantageous to consider a single chart, based on only one statistic, to simultaneously monitor the process mean and variance. In this paper, we propose the adaptive non-central chi-square statistic chart. This new chart is more effective than the adaptive (X) over bar and R charts in detecting disturbances that shift the process mean, increase the process variance, or lead to a combination of both effects. Copyright (c) 2006 John Wiley & Sons, Ltd.

Crystal structure of bis(acetylacetonato)-bis(3-methylpyridine)-nickel(II) dihydrate, Ni(C6H7N)(2)(C5H7O2)(2)center dot 2H(2)O

C22H32N2NiO6, triclinic, P (1) over bar (no. 2), a = 8.335(1) angstrom, b = 9.314(1) angstrom, c = 17.045(2) angstrom, alpha = 88.45(1)degrees, beta = 82.12(1)degrees, gamma = 70.296(9)degrees, V = 1233.7 angstrom(3), Z = 2, R-gt(F) = 0.050, wR(ref)(F-2) = 0.177, T = 293 K.

Crystal structures and luminescence properties of La3Zr4F25 and alpha-LaZr3F15

During a study of the LaF3-ZrF4 system, both La3Zr4F25 and alpha-LaZr3F15 compounds have been evidenced. Their crystal structures have been determined from single-crystal X-ray diffraction data. La3Zr4F25 crystallises in the cubic system with a= 12.384 Angstrom and I (4) over bar 3d space group (no. 220). Its crystal structure is built up of (ZrF6)(2-) octahedra and (LaF8)(5-) dodecahedra sharing corners. The low temperature form, alpha, of LaZr3F15 is orthorhombic (space group Pmmn, no. 59) with a = 15.721 Angstrom, b = 16.299 Angstrom, c= 8.438 Angstrom. Its structure is built of corner-sharing tricaped trigonal prisms surrounding the La3+ ions and both octahedra and monocapped trigonal prisms encompassing the Zr4+ ions. This structure is characterised by dynamically disordered (ZrF6)(2-) complex anions.The Eu3+ luminescence properties of these phases have been investigated and are discussed in relationship with their crystal structures.

X charts with supplementary samples to control the mean and variance

A standard X chart for controlling a process takes regular individual observations, for instance every half hour. This article proposes a modification of the X chart that allows one to take supplementary samples. The supplementary sample is taken (and the (X) over bar and R values computed) when the current value of X falls outside the control limits. With the supplementary sample, the signal of out-of-control is given by an (X) over bar value outside the (X) over bar chart's control limits or an R value outside the R chart's control limit. The proposed chart is designed to hold the supplementary sample frequency, during the in-control period, as low as 5% or less. In this context, the practitioner might prefer to verify an out-of-control condition by simply comparing the (X) over bar and R values with the control limits. In other words, without plotting the (X) over bar and R points. The X chart with supplementary samples has two major advantages when compared with the standard (X) over bar and A charts: (a) the user will be plotting X values instead of (X) over bar and R values; (b) the shifts in the process mean and/or changes in the process variance are detected faster.

Study of the elderly females' voice by phonetography

This study was carried out to investigate the voice characteristics of 40 healthy females with no voice disorders, ranging in age from 60 to 84 years ((X) over bar = 68.2 +/- 5.74 years). Measurements over all the entire phonational range were obtained by phonetography. The subjects were asked to sustain the vowel /a/ in modal register for a minimum of 5 seconds in the highest and lowest intensities after hearing the semitones C, E, G, and A, over all phonational ranges. The results indicated expansion of the low and reduction of high ends of the pitch range, decrease of the pitch numbers of the vocal range, restriction of the lowest and highest limits of the intensity, and reduction of either the maximum phonational range and the phonetogram area. The phonetography technique has shown efficacy to investigate the voice characteristics of elderly females.

X-ray powder data and bond valence of La0.65Sr0.35MnO3 after Rietveld refinement

Powder X-ray diffraction (XRD) data were collected for La0.65Sr0.35MnO3 prepared through an alternative method from a stoichiometric mixture of Mn2O3, La2O3, and SrO2, fired at 1300 degreesC for 16 h. XRD analysis using the Rietveld method was carried out and it was found that manganite has rhombohedral symmetry (space group R(3) over bar c). The lattice parameters are found to be a=5.5032 Angstrom and c=13.3674 Angstrom. The bond valence computation indicates that the initial inclusion of Sr occurs at higher temperature. (C) 2002 International Centre for Diffraction Data.