bluuebunny/crossref_metadata_2025 huggingface dataset:
Eruptive Phenomena near the Galactic Centre
Authors: J H Oort
Published: January 2007

Four categories of expanding features are described: (a) Features observed in the 21 cm radiation of atomic hydrogen, (b) agglomerations of dense molecular clouds, (c) an extended ionized-hydrogen feature, (d) high-velocity "clouds" of ionized gas within ∼ 1/2 pc from the centre. (a) These lie between R ∼ 1 and ∼ 4 kpc, in a region where there is little or no normally rotating gas. The velocity components in radial direction are between 50 and 170 km s-1 and are usually, if not always, directed away from the centre. The largest have masses ranging from two to eighty million times that of the Sun. They have arm-like structures. These seem to be no expanding H I features within R ∼ 750 pc. The hydrogen within this distance appears to be quiescent, and rotates with the circular velocity. It permits derivation of the gravitational field. (b) Dense molecular clouds exist within R ∼ 250 pc. Their distribution is extremely asymmetrical. Velocities are much lower than the circular velocities; they must move along highly excentric paths, and have probably been expelled from the centre. Direct evidence for such expulsion is given by a dense molecular ring at R = 190 pc which expands at an average velocity of 150 km s-1. (c) Ionized hydrogen shows an arc-like structure at R ∼ 40 pc, presumably likewise ejected from the centre. (d) Observations of a Ne II line at 12.8 μm show highly turbulent gas with random velocities up to at least 200 km s-1 in a region extending to about 1/2 pc from the centre. These clouds are reminiscent of the conditions in type II Seyfert nuclei, though on a very much smaller linear scale. In the same region there is a strong concentration of radiation at wavelengths of 10 μm and longer, due to dust, probably heated by supergiants or star clusters.

A noteworthy property of the central region is that the expanding H I- and molecular features, and probably also the rotating H I disk, lie in a plane which is inclined to the general galactic plane; the inclination is about 10°.

The radio source at the galactic centre (Sagittarius A) contains an extremely compact component. The diameter of this nucleus is about 0 Prime-.001, corresponding to 10 astronomical units, or 1.5 × 109 km. It may contain the energy source for the observed expulsion phenomena. These require initial kinetic energies between 1054 and 1055 erg, to be imparted at intervals of a few million years.
Gravity Power
Authors: D Lynden-Bell
Published: January 2007

Double whirlpools above and below a black hole cause the beaming and double structure of radio sources. The evidence for the widely held view that gravitational energy powers quasars is reviewed. After a brief discussion of other models an account is given of the standard accretion disk and ways in which such disks may power galactic nuclei and quasars. Finally the problem of creating large black holes cosmogonically is considered.
Accretion and the Quasar Phenomenon
Authors: Martin J Rees
Published: January 2007

Quasars are interpreted as massive black holes in galactic nuclei which are fuelled by capturing gas or stars from their surroundings. This paper discusses the supply of gas, the nature of the inflow (disclike or quasispherical) and the radiation processes.
Absorption in the Spectra of Quasi-Stellar Objects
Authors: E M Burbidge
Published: January 2007

A review of the key discoveries concerning absorption lines in QSOs is given. A number of recent studies bearing on the nature and origin of the absorption are discussed. It is concluded that it is most likely that the bulk of the absorption is intrinsic to the QSOs.
The Large Scale Structure of Extra-Galactic Radio Sources (>1 Arcsecond)
Authors: A G Willis
Published: January 2007

Current data on the structures of extended extragalactic radio sources are reviewed. The major technique used to study such sources is aperture synthesis. Thus the review begins with a brief description of the techniques used in aperture synthesis and the advantages and disadvantages of the method.

Section 2 contains a discussion of the source properties which can be derived from multi-wavelength aperture synthesis observations of an individual radio source. The following Sections 3 and 4 describe the general morphological characteristics of extended extragalactic radio sources. Some recent observations from the Westerbork radio telescope are used to illustrate these properties. Finally, Section 5 attempts to relate both morphological characteristics and integrated source parameters directly to activity within the nuclei of radio galaxies and quasars.
Structure and Time Variations of Compact Radio Sources in Galaxies and Quasars
Authors: K I Kellermann
Published: January 2007

High resolution observations made with intercontinental arrays of up to seven radio telescopes permit resolutions better than one thousandth of an arc second, and have disclosed remarkably complex structure in the nuclei of galaxies and quasars. Dimensions as small as a few hundredths of a parsec have been measured for the nuclei of some nearby galaxies; the source at the nucleus of our own Galaxy contains a component only 7 A.U. across and puts a limit on the size of the fundamental energy machine at the Galactic nucleus.

In some compact sources, individual components appear to separate with linear velocities well in excess of the speed of light. Although a variety of explanations have been offered, none are entirely satisfactory.
Energetics of Compact Radio Sources
Authors: L Woltjer
Published: January 2007

The model sensitivity of the energetics of compact radio sources is discussed, and it is shown that very reasonable total energies may be inferred.
Physical Problems Associated with BL LAC Objects and QSOs
Authors: G Burbidge
Published: January 2007

Physical problems associated with Compton effect, apparent super-light velocities and the energetics of BL Lac objects and QSOs are discussed.
Physical State of the Emission-Line Region
Authors: Donald E Osterbrock
Published: January 2007

The physical properties of the ionized gas in the active nuclei of Seyfert and radio galaxies derived from their emission-line spectra, are reviewed. Mean densities and temperatures in Seyfert 2 and narrow-line radio galaxies are in the ranges <103- 104cm-3and 10 000° - 20 000° respectively, while in the narrow-line regions of Seyfert 1 and broadline radio galaxies the temperatures are similar but the densities range up to 106cm-3. In the broad-line regions the densities are 108cm-3or greater. The abundances of the elements seem more or less normal. The relative strengths of the lines approximately match photoionization models with a power-law input spectrum, including the presence of high-ionization with lines such as [Fe X] and [Fe XI] along with great strength of neutral and low-ionization lines such as [O I], [N I] and [S II]. The Fe II emission which occurs in most Seyfert 1 galaxies but is much weaker or absent in broad-line radio galaxies occurs in the broad-line high-density region. Its excitation has been attributed to resonance fluorescence; this mechanism is at present being studied in detail observationally. The internal velocities observed in active nuclei are largely due to mass motions. The masses of ionized gas in the dense high-velocity regions are relatively small, and the structure of the gas must be highly filamentary or inhomogeneous. Dust is an important constituent of the active nuclei.
Models of Radiation-Driven Outflow
Authors: R Kippenhahn
Published: January 2007

The physics of radiative heating and of radiative acceleration in the neighbourhood of a nonthermal energy source is discussed. As an application radiatively driven winds flowing out from the source can be investigated. One can show that very high terminal velocities can be reached. Instabilities of the wind solutions produce shock waves moving outwards supersonically relative to the outflowing wind. These shock waves have such properties that they produce absorption lines which resemble the observed absorption line systems in QSOs.
The HEAO-B X-ray Telescope and its Observing Program
Authors: Riccardo Giacconi
Published: January 2007

A brief description is given of the performance characteristics of the HEAO-B X-ray telescope observatory. Particular emphasis is given to the descriptions of the parameters whose knowledge is required to establish an observational program. Since a substantial fraction of the observing time will be made available to Guest Investigators, the manner in which a Guest Investigator program may be run on the HEAO-B facility is outlined. The detailed observing program by the Consortium Institutions responsible for the HEAO-B program is summarized.
Future Prospects for Spectroscopic and Direct Work: Optical and UV
Authors: E Margaret Burbidge
Published: January 2007

A description of the main features and proposed instrumentation of the 2.4 m Space Telescope is given. Highlights of work that can be planned on active nuclei of galaxies, QSOs, and BL Lac objects are briefly outlined, involving spectroscopy over wavelengths from 1200 Å to 1 mm, direct imaging with 0".1 resolution, and the capability for 0".1 resolution along the spectrograph slit. The resolution, the much reduced sky background, and the full wavelength coverage also make possible important observations relevant to cosmology.
Future Prospects of Radio Observations of Active Nuclei
Authors: H van der Laan
Published: January 2007

The prospects for future developments in radio observations pertaining to active nuclei are briefly discussed and areas of potential advancement are described.
The Cosmological Evolution of Quasars
Authors: Maarten Schmidt
Published: January 2007

There is compelling evidence that quasars, both optically selected and radio selected ones, exhibit strong cosmological evolution. If the space density is an exponential of cosmic time, then the characteristic time of decline is one-tenth of the age of the Universe. Quasars with flat radio spectrum appear to show less cosmological evolution.
Clustering, Pairing and Anisotropy of QSOs
Authors: D Wills
Published: January 2007

Evidence for non-uniformity of the distribution of QSOs over the sky is reviewed. Topics discussed include associations of QSOs with galaxies, pairing of QSOs and the distribution of radio-detected QSOs over the sky. Periodic structure in the distribution of QSO emission-line redshifts is also discussed, and recent work on the surface density of QSOs at various apparent magnitudes is summarised. Very little compelling evidence exists at present against the view that QSOs are distributed uniformly across the sky and are unassociated with bright galaxies or with other QSOs.
Computer Simulation of Low-dispersion Spectra Obtained Using a Fehrenbach-Prism in the Converging Beam of a 1.5 m F/8.6 Telescope
Authors: P Kjærgaard  , J Ravn
Published: January 2007

A computer simulation of low-dispersion spectra obtained using Fehrenbach-prisms in the converging beam of a 1.5 m F/8.6 telescope has shown that most quasars of redshift smaller than z = 2.0 can be distinguished from white dwarfs - only white dwarfs of type F may look like quasars with abnormally weak Mg II emission and with redshift between z = 0.35 and z = 0.95. With the 1.5 telescope this technique can with certainty be used down to B = 18 magnitude.
The Hubble Diagrams for Quasars
Authors: John N Bahcall  , Edwin L Turner
Published: January 2007

The optical Hubble diagram for a complete sample of 112 quasars is constructed for q
0 = 1. With no correction for selection effects, the Hubble diagram shows a strong correlation of magnitude with redshift (slope 4.43 ± 0.44; correlation coefficient of 0.956). These uncorrected results place an interesting limit on luminosity evolution. The optical and radio Hubble diagrams are also discussed after applying the proper corrections for selection effects.
The Nature of the Unidentified High Latitude Radio Sources
Authors: M S Longair
Published: January 2007

A new optical survey of the fields of 3CR radio sources indicates that about 90-95 per cent of the high latitude 3CR sources can be identified with radio galaxies and quasars with apparent magnitudes less than about 23. At the faintest magnitudes, 20 < m < 23, all the new identifications are galaxies. These results suggest that the unidentified high latitude radio sources are radio galaxies and that like quasars they exhibit strong cosmological evolution. The new identifications are candidates for use in classical cosmological tests such as the m - z relation and for studies of the astrophysics of galaxies and radio sources at epochs significantly earlier than the present. The cosmological significance of these studies and of their extension to lower flux densities is described.
Quasars and Galactic Evolution
Authors: L Woltjer
Published: January 2007

The evolution of quasars is discussed. It is noted that substantial clustering may be present at faint magnitudes. The relationship between quasar evolution and galactic evolution is considered.
An Extended Analysis of the Spectrum of Trebly-Ionized Strontium
Authors: Willy Persson
Published: January 2007

The analysis of the spectrum of Sr IV emitted from a sliding spark discharge has been extended. In all, wavelengths and classifications of some 1200 Sr IV lines in the 6500-250 Å range are now known, about one half of them being newly classified. The analysis has yielded the positions of the missing 4s24p4(1D)4d2G9/2level, of most levels in the 4s24p47s, 6p, 6d, 4f, 5gand 6hconfigurations, of about half of the levels in the 4s4p54dconfiguration and also of some levels in the 5fand 6gconfigurations. In all, 255 Sr IV levels are now known. Most of the observed configurations have been interpreted theoretically, including effects due to configuration interaction. A strong 4s24p44f"leftarrow-" 4s4p54dinteraction has been observed. The ionization energy is estimated to be 453 930 ± 25 cm-1(56.279 ± 0.003 eV).
Systematic Investigations of Binding Energies of Inner-Shell Electrons in Superheavy Quasimolecules
Authors: Gerhard Soff  , Joachim Reinhardt  , Wilfried Betz  , Johann Rafelski
Published: January 2007

Electronic binding energies in superheavy quasimolecules are calculated using the monopole approximation, finite size and screening effects are included. The validity of the monopole approximation is discussed. A phenomenological description of the binding energy as a function of the total charge (Z1+Z2) and the two-center separationRis given. It is shown, that the 1sσ-ionization rate does not depend on the projectile or target charge, but only on the total charge of the superheavy quasimolecule.
Angular Distribution Measurements of Gamma-rays from Unbound T = 1 States in 22Na
Authors: R Hentelä  , J Keinonen
Published: January 2007

Angular distributions have been measured at six 21Ne(p, γ)22Na analogue resonances, with Ep
= 0.70, 0.77, 1.09, 1.21, 1.56 and 1.84 MeV, and at a candidate for analogue resonance with Ep
= 1.11 MeV. Gamma-ray mixing ratios have been obtained for the first time for the decays of these levels with determination of spin-parity assignments. The spins and parities for the bound states at 1.98 and 4.36 MeV have been deduced. Transition strengths provide information on the isoscalar and isovector strengths in the self-conjugated nucleus 22Na.
Spectra of Very Highly Ionized Atoms
Authors: E Ya Kononov
Published: January 2007

Recent laboratory investigations of the spectra of highly ionized atoms are reviewed. These include some interpretations of X-ray and VUV spectra of elements heavier than iron. New theoretical data are compared with experimental ones. The possible accuracy of wavelength measurements for spectra produced with specified light sources is discussed.
Experimental Compton Profiles for Some Alkali Halides
Authors: T Paakkari  , V Halonen
Published: January 2007

Compton profiles of polycrystalline alkali halides NaF, NaCl, NaBr, KF, KCl, and KBr and measured using 59.54 keV γ-rays from an241Am source. The results are corrected for instrumental broadening and for the effects of multiple scattering. Results are compared with those calculated in the MO-LCAO approximation (Paakkari et al., Phys. Fenn.9, 207, 1974). Good agreement is observed with the theory and all experimental results coincide with the free ion model at high momenta. Accurate multiple scattering corrections are also calculated for earlier data on LiF, LiCl, and LiBr. The results confirm the earlier findings by Paakkari et al. (1974).
Oxygen Content Analysis of Metal Surfaces with Resonant α-Scattering
Authors: L O Norlin  , B Orre  , G Possnert  , K Johansson
Published: January 2007

The thickness of the thin native oxygen layers on Al, Fe, Co, Ni and Gd metals have been determined by making use of the 3.05 MeV resonance in the elastic scattering reaction 16O (α, α) 16O. The surfaces of iron have been studied specially for different ways of preparation, e.g., evaporation, sputtering, passivation. The advantageous application of the method to interfaces is shown in an investigation of an iron-aluminium sample.
The Phase Problem in Crystallography: Proposal for an Experimental Solution
Authors: R M J Cotterill  , L Gerward  , A Lindegaard-Andersen
Published: January 2007

It is suggested that use of an amplitude modulated beam produced in an electron, X-ray or neutron interferometer could be used to increase the information content in a crystal diffraction pattern.
Study of S VII in the Vacuum Ultraviolet
Authors: H P Garnir  , Y Baudinet-Robinet  , P D Dumont  , M Eidelsberg
Published: January 2007

The spectrum of S VII has been observed between 500 and 1200 Å using the beam-foil excitation and the triggered-spark source. Twelve new lines have been observed and classified as transitions between 2p53s, 3pand 3dconfigurations.

Energies and designations are given for 12 new levels of these configurations. Lifetimes have been measured for 7 levels.
The Quartet Term System of Doubly Excited O VI
Authors: F Hannebauer  , H V Buttlar  , P H Heckmann
Published: January 2007

A total of 130 transitions in H-like, He-like, Li-like and Be-like oxygen have been observed in the wavelength region 7-32 nm using beam-foil excitation. A number of new lines are assigned to transitions in the doubly excited quartet system of O VI. The structure of this term system is derived from theoretical and experimental evidence. It is compared to the doubly excited term systems within the Li isoelectronic sequence.
On the Observation of Two-Proton Azimuthal Angle Correlations in 2 GeV/Nucleon Heavy Ion Interactions
Authors: B Jakobsson
Published: January 2007

A weak two-proton azimuthal angle back-to-back correlation which may indicate the presence of quasi elastic first order proton-proton scattering in16O + CNO reactions at 2 GeV nucleon has been observed. Low and medium multiplicity16O + AgBr reactions show the same tendency, while the dominant feature of the two-proton azimuthal angle distribution for very high multiplicity events is a blockade against pairs with relative angles between 2π/3 and 7π/8.
Infrared Emission Spectrum of Lutecium and Extended Analysis of Lu I
Authors: J Vergès  , J-F Wyart
Published: January 2007

155 emission lines of lutecium have been recorded by means of Fourier Transform Spectrometry in the spectral range 2692-10 082 cm-1. The magneticAand electricBhyperfine constants of the combining levels have been measured for 40 lines, and have led to a revision and extension of the energy level scheme. The configurations 5d26sand 5d6s6phave been completed; the first levels of 6s27p, 5g6s2and 5d26pare identified at 29 432, 39 336 and 40 558 cm-1respectively.
The Electronic Spectrum of the Gaseous AlI Molecule
Authors: E Martin  , R F Barrow
Published: January 2007

The electronic spectrum of AlI in the visible region has been photographed both in emission and in absorption. Earlier assignment of features to thea13Π0+-X1Σ+anda23Π1-X1Σ+systems has been confirmed and extended. RKR potentials for theX,a1anda2states have been constructed and used to calculate Franck Condon factors andr-centoids for the transitions. Using previous observations of theA1Π-X1Σ+continuum and the calculated potential for the ground state, the course of theA1Π potential is determined: the dissociation energy of AlI is found to beD00= 3.793 ± 0.020 eV.
Precision Estimates of the Predissociation Rates of the OH A2Σ State (v ⩽ 2)
Authors: J Brzozowski  , P Erman  , M Lyyra
Published: January 2007

The lifetimes of 108 different rotational levels of the OHAstate (υ = 0-2) have been measured at high spectral resolution using the High Frequency Deflection technique. From these lifetimes the variation of the electronic transition moment is deduced as well as the predissociation rates for levels above the dissociation limit and the formation rate of OH through inverse predissociation.
Collisional Contributions to the Nonlinear Current Density of a Turbulent Plasma
Authors: R Jancel  , L Stenflo
Published: January 2007

The collisional contributions to the second order nonlinear current density are calculated for a magnetized turbulent plasma in the "weak collisional regime".
Determination of the Ferromagnetic Curie Temperature for Fe40Ni40P14B6 (Metglas 2826)
Authors: Sigurds Arajs  , C A Moyer  , K W Brown
Published: January 2007

Magnetization of amorphous Fe40Ni40P14B6 (Metglas 2826) has been determined as a function of temperature between 320 K and 740 K. The Arrott-Belov-Kouvel (ABK) plots have been constructed for this material. The parabolic extrapolations give the ferromagnetic Curie temperature T
c = (520 ± 2) K which is identical to that obtained by the kink-point method in 50 Oe applied field.
Large-q Form Factors for Light Atoms
Authors: I Øverbø
Published: January 2007

Atomic form factors for momentum transfers between 0.1m
e
c and infinity are given for the neutral atoms 3Li through 19K and for 22Ti.
Cluster Model Wave Function and the r.m.s. Radius of 7Li
Authors: K Srinivasa Rao  , R Sridhar
Published: January 2007

The ground state wave function of 7Li, considered to be made of an alpha particle and a triton cluster configuration, including all the nucleon exchange terms arising out of the antisymmetrization of a two oscillator shell model wave function, is used in the calculation of the root mean square (r.m.s.) radius of 7Li with a view to determine the range of the parameters in the wave function.
The Transitions 3s-3p and 3p-3d, and the Ionization Energy in the Na I Iso-electronic Sequence
Authors: Bengt Edlén
Published: January 2007

Simple expressions inZfor the fine-structure intervals of 3p2Pand 3d2Dand for the transition energies 3s-3pand 3p-3dare derived from experimental data in the iso-electronic sequence of Na I-like spectra from S VI to Mo XXXII. The formulae provide a check on the accuracy of existing measurements and an easy interpolation of missing data. By a combination of the resulting energy values of 3d2D5/2,3/2with the ionization energies ofnf2F7/2,5/2, given by a formula based on the polarization concept, the series limits are derived from observations of the transitions 3d-nf. The results are summarized in a semi-empirical expression inZfor the ionization energy valid forZ⩾ 16. Finally, interpolation formulae are given for the line strengths of the transitions 3s-3pand 3p-3dbased on calculations by A. W. Weiss.
Wave Interaction in a Beam-Plasma System in Presence of Dispersion and Higher Order Non-Linear Effects
Authors: M Lisak
Published: January 2007

The third-order perturbation theory based on the method of multiple scales is applied in order to describe wave interactions in a beam-plasma system. The formalism includes simultaneous effects of dispersion and nonlinearities giving rise to self and mutual interactions. Some travelling wave solutions are obtained in special cases of physical interest.
The Cranking Moment of Inertia in a Static Potential
Authors: R Bengtsson  , I Hamamoto  , R H Ibarra
Published: January 2007

Taking into account the self-consistency condition for the deformation, we estimate the cranking moment of inertia in the absence of pair-correlations for the Woods-Saxon potential and various versions of the modified oscillator potential. We investigate the expectation that in a static potential the moment of inertia is almost equal to the rigid-body moment of inertia at the self-consistent deformation. We examine especially the consequence of the presence of the l
2 term in the conventional modified oscillator potential.
DYRK1A Autophosphorylation on Serine Residue 520 Modulates Its Kinase Activity via 14-3-3 Binding
Authors: Alvarez Mónica , Altafaj Xavier , Aranda Sergi , de la Luna Susana
Published: January 2007

Dual-specificity tyrosine-phosphorylated and regulated kinase (DYRK) proteins are an evolutionarily conserved family of protein kinases, with members identified from yeast to humans, that participate in a variety of cellular processes. DYRKs are serine/threonine protein kinases that are activated by autophosphorylation on a tyrosine residue in the activation loop. The family member DYRK1A has been shown to phosphorylate several cytosolic proteins and a number of splicing and transcription factors, including members of the nuclear factor of activated T cells family. In the present study, we show that DYRK1A autophosphorylates, via an intramolecular mechanism, on Ser-520, in the PEST domain of the protein. We also show that phosphorylation of this residue, which we show is subjected to dynamic changes in vivo, mediates the interaction of DYRK1A with 14-3-3β. A second 14-3-3 binding site is present within the N-terminal of the protein. In the context of the DYRK1A molecule, neither site can act independently of the other. Bacterially produced DYRK1A and the mutant DYRK1A/S520A have similar kinase activities, suggesting that Ser-520 phosphorylation does not affect the intrinsic kinase activity on its own. Instead, we demonstrate that this phosphorylation allows the binding of 14-3-3β, which in turn stimulates the catalytic activity of DYRK1A. These findings provide evidence for a novel mechanism for the regulation of DYRK1A kinase activity.
A strategy for rapid analysis of the variations in the reduced distribution function of liquid metals and metallic glasses
Authors: Kramer M. J.
Published: January 2007

Pulsed neutron sources and third-generation synchrotron sources provide sufficiently high flux to acquire high wave momentum diffraction patterns suitable for pair distribution function (PDF) analysis in a matter of minutes to seconds, and even less. This allows for sequential data acquisition of a sample subjected to thermal, mechanical and even magnetic forces. Understanding the dynamics of the material's response to external stimuli will require new ways of analyzing the massive amounts of data collected during these time-resolved studies. The change in the PDF can be quickly evaluated using only the change in the measured intensities from an arbitrary initial state. With appropriate scaling factor, these can provide a quantitative measure of how the pairwise correlations change with external stimuli.
A simple model for dynamic small-angle X-ray diffraction in colloidal crystals
Authors: de Beer Alex G. F. , Petukhov Andrei V.
Published: January 2007

A simple model is presented that allows calculation of the small-angle X-ray diffraction patterns of perfect colloidal crystals. The model is based on the Wentzel–Kramers–Brillouin approximation and permits a straightforward evaluation of multibeam interactions. Results are illustrated by several examples.
Hydrostatic low-range pressure applications of the Paris–Edinburgh cell utilizing polymer gaskets for diffuse X-ray scattering measurements
Authors: Chapman Karena W. , Chupas Peter J. , Kurtz Charles A. , Locke Darren R. , Parise John B. , Hriljac Joseph A.
Published: January 2007

The use of a polymeric Torlon (polyamide–imide) gasket material in a Paris–Edinburgh pressure cell forin situhigh-pressure X-ray scattering measurements is demonstrated. The relatively low bulk modulus of the gasket allows for fine control of the sample pressure over the range 0.01–0.42 GPa. The quality of the data obtained in this way is suitable for Bragg and pair distribution function analysis.
An apparatus for electric-field-induced protein crystallization
Authors: Al-Haq Muhammad Imran , Lebrasseur Eric , Choi Wan-Kyu , Tsuchiya Hidenori , Torii Toru , Yamazaki Hiroki , Shinohara Etsuo
Published: January 2007

A new device has been fabricated for electric field-induced protein crystallization with the microbatch method. In conjunction with this, a specialized tray using inexpensive plastic film has been developed for economical set-up of the experiments. Crystallization can be conducted using AC or DC voltage.
Structural investigation of the photoinduced spin conversion in the dinuclear compound {[Fe(bt)(NCS)2]2(bpym)}: toward controlled multi-stepped molecular switches
Authors: Trzop Elzbieta , Buron-Le Cointe Marylise , Cailleau Hervé , Toupet Loïc , Molnar Gabor , Bousseksou Azzedine , Gaspar Ana B. , Real José Antonio , Collet Eric
Published: January 2007

The photocrystallographic investigation of the light-induced excited spin-state trapping effect in the dinuclear spin-crossover compound {[Fe(bt)(NCS)2]2(bpym)} is reported. In this system, each of the two Fe sites may be either in the high-spin (HS) or in the low-spin (LS) state, so that the molecule corresponds to a three-state system (LS–LS, HS–LS and HS–HS). At low temperature, the laser excitation wavelength controls the photoswitching from the stable LS–LS state to one of the metastable excited states (HS–LS or HS–HS), and also between these two excited states. Significant changes in the crystalline structure associated with the photoinduced change of spin state are detailed here. The low-temperature photoinduced states look similar to the corresponding states observed at thermal equilibrium within the unit-cell thermal contraction.
Inhibin: Regulation of reproductive function and practical use in females
Authors: MEDAN Mohamed S. , ARAI Koji Y. , WATANABE Gen , TAYA Kazuyoshi
Published: January 2007

Inhibins are gonadal glycoprotein hormones selectively and potently inhibiting follicle‐stimulating hormone (FSH) secretion from the pituitary gland. Inhibins are produced mainly by the ovary and are purified from follicular fluid. Inhibins were shown to be produced in two forms through dimeric assembly of an α‐subunit and one of two closely related β‐subunits to form inhibin A (α‐βA) and inhibin B (α‐βB). Although inhibin subunits are expressed in various tissues, the gonads are the major source of circulating inhibins. While inhibins may act as a paracrine or autocrine factor in some tissues, their best understood roles are as endocrine regulators of pituitary FSH. In this review we focus our attention on more recent developments in inhibin research. We describe patterns of inhibin A and B secretion during the estrous cycle. We also review the immunization against inhibin α subunit as a practical method for superovulation. Superovulation has been induced successfully by passive or active immunization against the inhibin α‐subunit in several species such as mice, rats, hamsters, guinea pigs, cows, mares, ewes and goats. Furthermore, several studies have shown that oocytes superovulated with immunization against inhibin α‐subunit have the ability to develop normally, suggesting that inhibin immunization could be used as a practical method for superovulation in a wide range of animal species.
Mechanisms involved in the cytosolic calcium ion elevation induced by activating factors in chicken and rat phagocytes
Authors: YONG Sheng , ABE Asaki , KONDO Yasuhiro
Published: January 2007

The aim of the present study was to determine the mechanism of cytosolic calcium ion concentration [Ca2+]ielevation in chicken and rat phagocytes stimulated with phorbol myristate acetate (PMA), leukotriene B4(LTB4), formyl‐methionyl‐leucyl‐phenylananine (fMLP) andSaccaromyces cerevisiaeculture supernatant (SCS). Pretreatment with EGTA completely suppressed the PMA‐induced [Ca2+]ielevation in rat and chicken phagocytes, suggesting that all the [Ca2+]ielevation induced in the PMA‐stimulated rat and chicken phagocytes was attributable to the influx of extracellular Ca2+. On the other hand, the elevation of LTB4‐, FMLP‐ and SCS‐induced [Ca2+]iwas only partially suppressed by ethyleneglycol‐bis (β‐aminoethyl)‐N,N,N′,N′‐tetraacetic acid ethylene (EGTA) pretreatment of phagocytes. The results indicated that two pathways of [Ca2+]ielevation, recruitment from the intracellular Ca2+store and influx of extracellular Ca2+, are involved in the [Ca2+]ielevation of LTB4‐, fMLP‐ and SCS‐stimulated phagocytes. In fMLP‐stimulated rat neutrophils, [Ca2+]ielevation showed a two‐phase pattern in which the time lag between the first and second phase was approximately 1 min. The EGTA treatment of the fMLP‐stimulated cells induced a reduction of the first phase level and a disappearance of the second phase. The reason for the special influence of EGTA observed in fMLP‐stimulated cells is unknown, but the disappearance of the second phase of the [Ca2+]imay be elicited by the EGTA‐induced decrease of the first phase [Ca2+]ielevation that depends on IP3and diacylglycerol induced by fMLP.
Evidence‐based implementation of adult asthma guidelines in the emergency department: A controlled trial
Authors: Doherty Steven R , Jones Peter D , Davis Lin , Ryan Nicholas JV , Treeve Verity
Published: January 2007

Objective:  To determine if an evidence‐based implementation (EBI) strategy could lead to the successful implementation of guidelines for the management of adult asthma in a large rural ED.

Methods:  This was a pre‐ and post‐intervention trial, comparing data for seven clinical indicators from a study hospital and a control hospital. Retrospective pre‐intervention audits were conducted at the study hospital for 3 months (1 April−30 June 2004) and the control hospital for 4 months (1 March−30 June 2004). The effect of an EBI to implement established guidelines for the management of asthma at the study hospital was compared with the effect of a mail‐out of guideline booklets and wall charts to the control hospital. Post‐intervention audits were then performed at both hospitals. Sustainability of the EBI was gauged by 12 month follow‐up data at the study hospital.

Results:  There were 55 presentations of adult asthma at the study hospital in the pre‐intervention phase and 67 post‐intervention. The corresponding numbers for the control hospital were 51 and 42, respectively. Following the EBI there were significant improvements at the study hospital for the documentation of severity (27–99%, P < 0.01), use of spirometry (38–84%, P < 0.01), medication delivery via spacer device (0–26%, P < 0.01), use of systemic steroids (66–84%P < 0.05), use of written short‐term asthma plans (14–82%, P < 0.01), reduction of ipratropium use in mild asthma (43–16%, P < 0.05) and reduction in antibiotic use in afebrile asthmatics (37–6%, P < 0.01). For the control hospital there was a significant increase in spirometry use from 2% to 40% (P < 0.01). For seven clinical indicators combined, compliance with the guideline increased from 38% to 79.1% (P < 0.01) at the study hospital, whereas there was no change at the control hospital, 44.3% to 43% (P = 0.75) There were 68 presentations at 12 month follow up at the study hospital and compliance with the seven clinical indicators was 78.2%.

Conclusion:  An EBI significantly improved compliance at the study hospital with no improvement noted in the control hospital. These improvements were maintained at 12 month follow up. An EBI can lead to significant improvements in the management of asthma at a large rural referral hospital ED and might have implications for hospitals with similar roles and profiles.
Psychosocial Care Needs of Children With Recent‐Onset Asthma
Authors: McNelis Angela M. , Musick Beverly , Austin Joan K. , Larson Polly , Dunn David W.
Published: January 2007

PURPOSE.  To examine psychosocial care needs of children with recent‐onset asthma.

DESIGN/METHODS.  Data were collected over 2 years from 63 children ages 8–14 years.

RESULTS.  Children's need for attention to specific aspects of their asthma care remained high over the 2 years, as did their perceived needs for information and support and their concerns and fears.

PRACTICE IMPLICATIONS.  Children have many needs, and healthcare professionals may not be providing care that addresses these needs. The Child Report of Psychosocial Care can be used as a quick tool to assess and guide interventions related to specific areas of need.
Maturing Responsibility in Young Teens Participating in an Asthma Camp: Adaptive Mechanisms and Outcomes
Authors: Buckner Ellen B. , Simmons Sharon , Brakefield Jennifer A. , Hawkins Ashley K. , Feeley Christine , Kilgore Laura A. Frizzell , Holmes Suzanne , Bibb Melissa , Gibson Linda
Published: January 2007

PURPOSE.  The purpose of this study was to describe adolescent adaptation in the four adaptive modes of the Roy Adaptation Model in campers attending a Young Teen Asthma Camp and relate that adaptation to the acquisition of asthma responsibility.

DESIGN AND METHODS.  The camp experience included asthma education and an opportunity to grow socially. A quasi‐experimental design investigated ratings of self‐efficacy and responsibility from before to after camp.

RESULTS.  Improvements in self‐efficacy supported adaptation in self‐concept and role function. Adolescents demonstrated maturing responsibility in asthma management in interdependence mode.

PRACTICE IMPLICATIONS.  Asthma camps are effective for delivering asthma education, enhancing maturation, and assisting with normalizing life experiences. Nurses can be instrumental in facilitating adolescents’ participation.
Presence of a Surface-Exposed Loop Facilitates Trypsinization of Particles of Sinsiro Virus, a Genogroup II.3 Norovirus
Authors: Kumar Shantanu , Ochoa Wendy , Kobayashi Shinichi , Reddy Vijay S.
Published: January 2007

Noroviruses (NoVs) are the causative agents of nonbacterial acute gastroenteritis in humans. NoVs that belong to genogroup II (GII) are quite prevalent and prone to undergo recombination, and their three-dimensional structure is not yet known. Protein homology modeling of Sinsiro virus (SV), a member of the GII.3 NoVs, revealed the presence of a surface-exposed 20-amino-acid (aa) insertion in the P2 domain of the capsid protein (CP) relative to the Norwalk virus (NV) CP, which is a well known hot spot for mutations to counter the host immunological response. To further characterize the role of the long insertion in SV, the capsid protein gene was expressed using the recombinant baculovirus system. Trypsinization of the resultant virus-like particles yielded two predominant bands (31.7 and 26.1 kDa) in sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blot analysis. N-terminal sequencing and analysis of the mass spectroscopic data indicated that these fragments correspond to residues 1 to 292 (26.1 kDa) and 307 to 544 (31.7 kDa). In addition, the above data taken together with the comparative modeling studies indicated that the trypsin cleavage sites of the Sinsiro virus CP, Arg292 and Arg307, are located at the beginning of and within the 20-aa insertion in the P2 domain, respectively. This study demonstrates that the presence of the surface-exposed loop in the GII.3 NoVs facilitates the trypsinization of the capsid protein in the assembled form. The SV particles remain intact even after trypsin digestion and retain the suggested receptor binding linear epitope of residues 325 to 334. The above results are distinct from those obtained from the trypsinization studies performed earlier on the NV (GI) and VA387 (GII) viruses, both of which lack the large surface insertion and associated basic residues. These new observations may have implications for host receptor binding, cell entry, and norovirus infection in general.
Cancer mortality in a synthetic spinning plant in Besançon, France
Authors: Hours M , Févotte J , Lafont S , Bergeret A
Published: January 2007

Objectives:To assess the mortality of a cohort of workers in a synthetic textile spinning plant and to evaluate the relationship between mortality from lung, liver and bladder cancer and the processes or the products used.

Methods:The study population consisted of male workers present for at least 6 months in the plant from 1968 to 1984. The cohort was followed until 1999. Vital status and the causes of death were determined by consulting national registries. The population of the Franche-Comté region was used for comparison. In total, 17 groups of exposure were assessed by the industrial hygienist, based on the consensus of an expert group that determined the exposure levels of each job to selected occupational hazards. Each worker was assigned to one or several groups, according to his occupational history. Confounding factors could not be assessed. Standardised mortality ratios (SMR) and 95% bilateral confidence intervals were calculated based on an assumed Poisson distribution of the number of cases to compare the plant mortality and the population mortality. Internal analyses were performed with Cox models in order to assess the risks of death related to the various exposures.

Results:In the whole cohort, mortality from all malignant neoplasms was lower than expected, but this was not significant. All the estimated SMRs were lower than or close to 1. The “hot -line fitters” (RR = 2.13; n = 9; 1.06 to 4.29) and the “fibre-drawing workers” (RR = 1.83; n = 20;1.09 to 3.07) experienced a statistically significant excess in mortality from lung cancer. A slightly elevated but not significant risk of death related to lung cancer (RR = 1.5; n = 41; 0.8 to 2.7) was observed in the groups with the highest exposure to mineral fibres. A statistically significant increase in cancer deaths was observed for workers with high exposure to dust (higher intensity: RR = 1.42; n = 79; 1.06 to 1.89).

Conclusion:Some findings, mainly of lung cancer, justify further exploration in other plants in this industry,
Auxin regulates lateral meristem activation in developing gametophytes ofCeratopteris richardii
Authors: Gregorich Michele , Fisher Roxanne
Published: January 2007

This study investigates the auxin regulation of lateral meristem activation in the gametophytes of the fern Ceratopteris richardii Brongn. Exogenous auxin in the form of α-naphthaleneacetic acid or 2,4,5-trichlorophenoxy-acetic acid repressed the activation of the lateral meristem, and generated a male-like body plan. The auxin antagonist p-chlorophenoxyisobutyric acid reduced activity of both the apical and lateral meristems, and produced a circular-shaped gametophyte. Disrupting auxin transport with 2,3,5-triiodobenzoic acid led to a time lag in lateral meristem activation, while disrupting auxin transport with n-1-naphthylphthalamic acid produced several different body plans generated by the formation of a second lateral meristem. These findings suggest auxin mediates the activation of the lateral meristem and regulates lateral meristem function. In addition, auxin transport may be necessary for communication between the lateral meristem and other regions of the developing gametophyte. Auxin also controls the position of rhizoids produced by the gametophyte, and exogenous auxin interferes with the sexual differentiation of the gametophyte. These results are summarized in a model of how auxin regulates lateral meristem activation and meristem activity during gametophyte development in C. richardii.
Reproductive consequences of Colletotrichum lindemuthianum (Ascomycota) infection on wild bean plants (Phaseolus vulgaris)
Authors: Bénard-Capelle Julien , Soubeyrand Samuel , Neema Claire
Published: January 2007

Fungal plant parasites can have strong reproductive consequences on their hosts, but little is known about the amount of parasite-induced fitness loss under natural conditions. We present data from wild populations of Colletotrichum lindemuthianum Sacc. & Magn., a fungal parasite that attacks the wild common bean (Phaseolus vulgaris L.). We estimated disease prevalence in two populations and fungal virulence by examining naturally infected plants for three fitness-related traits: number of seeds per pod, mass of seed per pod, and germination rate. We observed that C. lindemuthianum infected nearly all plants in the study populations, but that the amount of infected pods per plant varied greatly. In addition, infection was associated with a reduction of host fitness-related traits only in pods with sporulating lesions. These findings suggest that C. lindemuthianum may constitute a significant selection pressure in wild populations, and that impact of spore production on host fitness may influence virulence evolution in this fungus.
Unraveling theAsteromenia peltataspecies complex with clarification of the generaHalichrysisandDrouetia(Rhodymeniaceae, Rhodophyta)
Authors: Saunders Gary W. , Lane Christopher E. , Schneider Craig W. , Kraft Gerald T.
Published: January 2007

The senior author was fortunate in 1996 to dive on the remote Houtman Abrolhos Islands of Western Australia and view in situ the stunning “ Asteromenia peltata ” that is so strikingly illustrated by John Huisman (viewable on AlgaeBase). Five years later, during excursions to Bermuda and Lord Howe Island (tropical eastern Australia), he observed and collected specimens referable to this species in both these localities. Based on their respective appearances in the field, it seemed unlikely that these entities from geographically remote regions represented the same species. Our molecular results not only confirm this suspicion, but further indicate that A. peltata sensu lato constitutes a complex of at least five distinct species. We restrict A. peltata to one of two species found in the western (sub)tropical North Atlantic, the second described herein as A. bermudensis sp. nov. Samples from Western Australia represent an undescribed species, A. exanimans sp. nov., while two entities collected from Lord Howe Island (A. anastomosans (Weber-van Bosse) comb. nov. and A. pseudocoalescens sp. nov.) conform to records variously reported as Asteromenia peltata and Drouetia coalescens . Specimens of D. coalescens from South Africa are also not representative of the genus Drouetia , but form a novel lineage within the Rhodymeniaceae. We included two species of Halichrysis in our molecular analyses and, in combination with observations of salient anatomical features, provide arguments for maintaining Asteromenia, Drouetia, and Halichrysis as distinct genera.