bluuebunny/crossref_metadata_2025 huggingface dataset:
BI Crucis
Authors: Altamore A. , Rossi C. , Viotti R.
Published: July 2016

BI Crucis is a 12 mag star whose optical spectrum is characterized by a red continuum and variable emission line spectrum (Allen 1974, Henize and Carlson 1980, Whitelock et al. 1983). In order to investigate its symbiotic character on 18 February 1983 we have obtained at the 1.5m ESO telescope a 59 Å/mm spectrogram of the 5700-6900 Å region. BI Cru displayed a very rich emission line spectrum with very strong Hα. and prominent HeI (5876 and 6678Å) lines. Several FeII lines are also present which appear optically thick (Figure 1). A few absorption features (NaI, 6269-84) of interstellar origin are present. However, we find no trace of TiO bands (or of neutral atoms) in spite of Allen’s (1974) finding, but in agreement with Whitelock et al. (1983). Allen (priv. comm.) remarks that in his spectrum there are slight ‘waves’ in the continuum that looked like TiO absorptions. Thus the symbiotic nature of BI Cru is mostly based on its long term IR variability (T≅280 d, Whitelock et al. 1983). They also found the first overtone vibration rotation band of CO at 2.3 μm in emission. The CO emission band was recently resolved by McGregor et al. (1987). This is the first observation of CO in emission in a symbiotic object. The red continuum is more probably a highly reddened hot continuum. We note that a weak continuum is present in the LWR IUE image taken in March 1981 (Fig.2). This spectrum also shows a few emission lines of Mgll and FeII. BI Cru is also a strong IRAS source. Following the model of Kenyon et al. (1986) for D-type symbiotics, the cool component of BI Cru could be reddened by circumstellar dust. A high resolution ESO CAT/CES red spectrum shows Hα doubled by a central absorption extending from −38 to −290 km/s with respect to the center of the emission line which suggests the presence of intermediate velocity winds like in other symbiotic stars.
What can we learn from ζ Aur binary systems?
Authors: Schröder K.-P.
Published: July 2016

ζ, Aur binaries are wide eclipsing systems (P ≃ 1...10 yrs), containing a late supergiant primary (G to M type) and an early dwarf companion (A0 V... B3 V ). Some recent studies of wind phenomena (mass loss rates), chromospheric properties and wind acceleration (of the supergiant) as well as wind accretion phenomena introduced by the gravitational interaction with the companion are presented, summarizing previous work of the Hamburg ’binary wind team’(mainly D. Reimers, R. Baade, A. Che-Bohnenstengel, K. Hempe, K.-P. Schröder).
The Problem of Spectral Classification of Stars in the Sequence S-SC-C
Authors: Boeshaar Patricia C. , Keenan Philip C.
Published: July 2016

The sequence of stars starting with type S and extending through the SC stars into the red carbon stars are brought into the following revised system of classification:

In this table X stands for the temperature type and the number to the right of the slant line is an abundance index which, as suggested by Ake (1978), is essentially a measure of C/O. Intensities of ZrO and TiO are given also.
The Occurrence of Abnormal Stars in Open Clusters
Authors: Abt Helmut A.
Published: July 2016

Morgan, Keenan, and others have found that low dispersions (80-130 Å mm-1) are ideal for obtaining spectral types and luminosity classes, especially for early-type stars. This is because at those dispersions certain blends are unresolved and remain useful, the hydrogen line wings are seen most clearly, and differences in rotational velocities are not so important. Such dispersions are also ideal or adequate for detecting some peculiarities, such as Am and Be spectra and some extreme Ap spectra, but they are inadequate for detecting abnormalities involving weak lines (as in Ap(Hg, Mn) stars) and line profiles (such as in shell spectra).
Criteria and Applications for Spectral Classification Outside the MK Domain
Authors: McCarthy M. F.
Published: July 2016

The area under discussion here lies beyond the domain of the MK system and includes studies of natural groups as detected in low dispersion studies; it extends to spectral regions studied now in the far ultraviolet and in the infrared and radio regions; in this paper primary consideration is given to optical spectra from the near infrared to the near ultraviolet. We give a description of “natural groups” and a brief description of new possibilities opened for research in this area through the introduction of thin prisms and the combination of prism and grating (GRISM). Finally a summary of spectral criteria useable outside the MK domain is presented.
Radio Emission from Cataclysmic Variables
Authors: Chanmugam G.
Published: July 2016

The study of radio emission from cataclysmic variables (CVs) is a new and developing field. Radio emission from novae, recurrent novae, dwarf novae and each of the subclasses (AM Her and OQ Her) of magnetic CVs have now been reported and are reviewed here. These observations are shown to provide, in general, a probe of the structure of the CV on length scales typically ≳1011cm. Radiation mechanisms, both incoherent and coherent, relevant to the observed radio emission are also discussed. These suggest that the red dwarf in AM Her and DQ Her is also magnetized and provides support for theories for the evolution of CVs which require a magnetized secondary star.
Multi-Wavelength Observations of Dwarf Novae during Outburst
Authors: Echevarría J.
Published: July 2016

Multi-wavelength observations of dwarf novae during outburst are presented here. Thirty three objects were observed, of which seventeen were at outburst. Six objects were caught during the rise, and a short flare was detected in SU UMa. It lasted 20 hours and reached a maximum increase of 3.6 in flux at 5500 A. The flare was simultaneous at all observed wavelengths.
A Full Cycle in the Evolution of a Classical Nova
Authors: Prialnik D.
Published: July 2016

A classical nova model was evolved through a complete cycle, i.e. accretion leading to outburst, mass loss and again accretion, ending in another outburst, by means of an implicit Lagrangian hydrodynamic code, which included diffusion (concentration, pressure and thermal terms), as well as an extensive nuclear reactions network between 28 isotopes of C, N, O, F, Ne, Na, Mg and Al. The initial model was a 1.25 M⊙ C-O white dwarf (WD) and the accretion rate assumed was 10−11 M⊙/yr. For more details of this calculation, see Prialnik (l986).
Low-Mass X-Ray Binaries in the LMC
Authors: Pakull M.W. , Beuermann K. , Angebault L.P. , Bianchi L.
Published: July 2016

We report results on three low-mass X-ray binaries (LMXB) in the LMC, obtained with EXOSAT, IUE and ground-based (ESO) telescopes: LMC X-2 which appears to be “Sco X-l”-like, LHG 83 and LHG 87. The latter are two weaker sources first detected in the course of the HEAO-B LMC survey. They have faint optical counterparts of which LHG 87 was only recently identified by us. In X-rays, they are characterized by ultrasoft X-ray spectra possibly characteristic of black-hole primaries. LHG 83 furthermore shows evidence for X-ray ionization of the surrounding interstellar medium, similar to the He III region around the black-hole candidate LMC X-l. X-ray binaries with masses of compact objects in excess of 3 M⊙ and ultrasoft X-ray spectra are comparatively frequent in the LMC. We suggest that subcritical accretion onto black holes takes place in LHG 83 and LHG 87.
Nāṣīr Ad-Dīn on Determination of the Declination Function
Authors: Hamadani-Zadeh Javad
Published: July 2016

A commentary, on the spherical astronomy in the Zīj-i Īlkhanī[1], written by the famous Naṣīr ad-Dīn aṭ-Ṭusī (c. 1270) would be an important contribution to the history of medieval astronomy. But we postpone this and attempt here to describe the contents of the third and fourth sections of Treatise III of this zīj. We hope that it will serve to elucidate a small part of this work, which has remained unexploited. I have made a preliminary English translation of the entire Zīj-i Īlkhanī, which awaits final revision and preparation for publication.

The rules explained verbally and without proof by Naṣīr ad-Dīn in the sections under consideration are similar to the ones described by Kāshi in his Zīj-i khāqānī and analysed by E. S. Kennedy in [2]. Therefore, we do not present our proofs of the rules, but refer the reader to [2].
A Note on Some Sanskrit Manuscripts on Astronomical Instruments
Authors: Ohashi Yukio
Published: July 2016

The earliest astronomical instruments in India are the śaṙku (gnomon) and the ghaṭikā (clepsydra). The former is mentioned in the Śulbasūtras, and the latter in the Vedāṅqajyotiṣa. Aryabhaṭa described a rotating model of the celestial sphere. After Aryabhaṭa, several instruments were described by Varāhamihira, Brahmagupta,Lalla, Śrīpati , and Bhāskara II. After Bhāskara II , some Sanskrit texts specialized on astronomical instruments were composed. The earliest text of this kind is the Yantra-rāja (AD 1370) written by Mahendra Sūri. It is also the first text on the astrolabe in Sanskrit. After Mahendra Sūri, Padmanābha, Cakradhara, Ganeśa-Daivajña etc. composed Sanskrit texts on instruments, but most of them remain unpublished.
Machine-Processing of Objective-Prism Plates at the Royal Observatory, Edinburgh
Authors: Clowes Roger G
Published: July 2016

This paper reviews the methods and early results of work in progress at the Royal Observatory, Edinburgh that involves the machine-processing of objective-prism plates. This work is in two categories: (i) semi-automated galaxy redshifts, and (ii) automated quasar detection. The galaxy redshifts are used, for example, to determine the radial velocities of clusters, to test cluster membership, to reveal superimposed clusters, and to reveal connecting bridges between clusters. Automated quasar detection uses selection criteria that are known, pre-defined and rigidly maintained to select complete samples of quasars. Unlike the earlier visual samples of optically-selected quasars these new samples are well suited to work in cosmology and the collective properties of quasars.
The Application of Optical Fibre Technology to Schmidt Telescopes
Authors: Dawe J.A. , Watson F.G.
Published: July 2016

The potential of the Schmidt optical system, when combined with optical fibres and linear detectors, is assessed. Recent work on the use of optical fibres at the U.K. Schmidt Telescope is described together with anticipated developments. In conclusion, there is a speculative consideration of the construction of a large, altazimuth Schmidt telescope (LAST).
The Determination of the Vignetting Function of A Schmidt Telescope
Authors: Dawe J.A.
Published: July 2016

Observational and geometric approaches to the problem of determining the vignetting function are discussed. A simple technique for producing a “flat-field” is described, and the various uses of such a flat-field to investigate the photometric accuracy and sensitivity of different emulsions are discussed.
Brand New Candidates For Deep Schmidt Plates
Authors: Capaccioli M. , Davoust E. , Lelièvre G. , Nieto J.-L.
Published: July 2016

With reference to the complementarity between large-scale, low-resolution and small-scale, high-resolution telescopes (Capaccioli et al., 1984), we briefly report here on very recent CFH telescope photographic observations of early-type galaxies which are good candidates for further investigations with Schmidt-type telescopes. The photographs were taken at the newly installed f/8 Cassegrain focus with good seeing conditions. The large scale ( ~ 7 arcsec mm -1) allows to overcame some of the major difficulties encountered in the reduction of the prime focus high resolution (FWHM~0".75) material (Nieto,1983).
Objective-Prism Galaxy Redshifts in Fields Around the South Galactic Pole
Authors: Parker Q.A. , MacGillivray H.T. , Dodd R.J. , Cooke J.A. , Beard S.M. , Kelly B.D. , Emerson D.
Published: July 2016

Measurements made with the COSMOS machine on deep objectiveprism photographs taken with the UK 1.2m Schmidt Telescope are being used to obtain approximate redshifts (accurate to ~ 0.01 in z) for large numbers of galaxies in fields near the South Galactic Pole. The data are suitable for investigations of the distribution of galaxies, such as the detection of large-scale density enhancements or voids.
Ground Based Developments - Reduction Systems
Authors: Grosbøl P.J.
Published: July 2016

The reduction of Schmidt plates is divided into scanning the plates, processing the data, and analyzing the results. At least two new measuring machines for analyzing Schmidt plates are being designed which will increase the total throughput to over 10 plates per day. The developments of microprocessors and mass storage open new possibilities for faster and cheaper processing of these large amount of data. Finally, the introduction of DataBase Management and Table Data systems will make it easier for astronomers to analyze the extracted informations. With these new developments the aim to make a detailed analysis the plates at the same rate at which they are obtained can be achieved within this decade.
The Cu I And Zn I-Like Spectra of Pr, Eu, Gd, Dy And Yb Emitted by a Tokamak Plasma in the 50–200 Å Range
Authors: Hodge W.L. , Finkenthal M. , Moos H.W. , Lippmann S. , Huang L.K. , Bar-Shalom A. , Klapisch M.
Published: July 2016

Spectra of rare earth elements, praseodymium, europium, gadolinium, dysprosium and ytterbium (Z=59 to Z=70) have been recorded from a high temperature (Te=1–1.4 keV) - low density (ne=1013cm−3) tokamak plasma, in the 50–200 Å range. The absolute brightnesses of the lines originating in 4–4 transitions of Cu I and Zn I-like ions of the above mentioned elements have been measured by means of a photometrically calibrated grazing incidence spectrometer. Newly identified Cu I-like, 4s2S1/2-4p2P1/2transitions in Pr30+, Eu34+, Gd35+, Dy37+and Yb41, and intercombination transitions 4s21S0-4s4p3P1, in the Zn I-like ions of the mentioned elements are presented. The identifications are based on interpolation of previous experimental results, ab initio energy level computations using the RELAC code and are substantiated by the time histories of individual spectral lines. The experimental line intensities of the Cu I and Zn I-like ions are compared with those predicted by a collisional-radiative model under the conditions of the tokamak plasma.
Space Resolved Measurements of the Emission of Intermediate and High Ionization States Obtained from Vacuum Spark Plasmas Using Xuv Multilayer Mirrors and a RbAP Crystal
Authors: Finkenthal M. , Stutman D. , Schwob J.L. , Underwood J.H.
Published: July 2016

The spatial extent of the regions from which lines of the Intermediate, NeI-like and high Li I-llke Ionization states of Ti, V, Fe, Co, and Ni, are emitted in a low inductance high-current vacuum spark plasma, has been determined using multilayer mirrors and a RbAP crystal. The spectra have been recorded in the 10–30 Å range. The main conclusion of the present work is that the intermediate ionization states are emitted from an extended plasma region, of the order of 200 microns, while the highly ionized states are formed, as it has been previously stated, In the minute plasma pinch.
Soft X-Ray Spectroscopy on the TFR Tokamak
Authors: Breton C. , de Michelis C. , Hecq W. , Mattioli M. , Ramette J. , Saoutic B. , Schwob J.L.
Published: July 2016

The 2m-grating radius, extreme grazing incidence (1.5°) Schwob-Fraenkel spectrograph was developed at the Racah Institute of Physics (under CEA contract) more than 10 years ago. The first results (using photographic plates) on the TFR tokamak permitted the indentification of the spectrum of highly ionised Mo ions in the 5-50 Å spectral region /1/. Subsequently, the system was modified by J.L. Schwob into a duochromator, using two channeltron electron multipliers independently movable along the Rowland circle. It was thus possible to obtain radial profiles of the emissivities of the strongest lines of the H-and He-like isoelectronic sequences of light impurities in the 18-42 Å spectral range /2/. Recently, the duochromator has been converted into a multichannel spectrometer by equipping it with a microchannelplate (MCP) detector again movable along the Rowland circle. The detector consists of a MgF2coated, funneled MCP, associated with a phosphor screen image intensifier and coupled by a flexible fiber optic conduit to a 1024 element photodiode array (controlled and read-out by a commercially available PAR-1461 EGG Princeton Applied Research optical multichannel analyser system). The first of this type of detector was developed at Princeton for the PLT and TFTR tokamaks and was described by Schwob et al /3/. An identical system has been installed on TFR, using a 20 /μm entrance slit and a 600 groove mm−1Jobin-Yvon holographic grating. This instrument has been routinely used during the last year of TFR operation to monitor spectra of both intrinsic impurities (C, 0, Cr, Fe, and Ni, with traces of Mn, Cl, and S) and purposely injected impurity elements in the 10-330 Å spectral range. The spectrometer has been used in both the spectrographic and the polychromator modes. In the former mode, spectra of highly-ionized, unstudied, heavy elements (injected either by the laser blow-off technique or as gaseous elements) have been obtained /4,5/. In the latter utilization (in which selected individual pixels are read-out as function of time) line radiance evolutions of several different Fe ions have been simultaneously obtained on a single discharge. This has allowed the impurity transport to be modelled /6/ even though the system was not absolutely calibrated, since different ionization degrees have different time evolutions.
Effect on Deuteron Temperature on Iron Forbidden Line Intensities in RF-Heated Tokamak Plasmas
Authors: Sato K. , Suckewer S. , Wouters A.
Published: July 2016

Two line ratios, the forbidden line at 845.5 Å to the allowed line at 135.7 Å in Fe XXII and the forbidden line at 592.1 Å to the forbidden line at 1118.2 Å in Fe XIX, have been measured as ion temperature-sensitive line ratios during rf heating in the Princeton Large Torus. The results indicate that deuteron collisions in plasmas of high deuteron temperature have a noticeable effect on the intensity of the forbidden lines. Measured relative intensities are compared with values from level population calculations which include deuteron collisional excitation between the levels of the ground configuration. The agreement between the observed and calculated ratios is within 30%. A method for deuteron (or proton) temperature measurement in tokamak plasmas is discussed.1More details about this experiment can be found in Ref. 2.
Dielectronic Recombination in the Average-Atom Model
Authors: More R.M. , Zimmerman G.B. , Zinamon Z.
Published: July 2016

Autoionization and dielectronic attachment are usually omitted from rate equations for the non–LTE average–atom model, causing systematic errors in predicted ionization states and electronic populations for atoms in hot dense plasmas produced by laser irradiation of solid targets. We formulate a method by which dielectronic recombination can be included in average–atom calculations without conflict with the principle of detailed balance. The essential new feature in this extended average atom model is a treatment of strong correlations of electron populations induced by the dielectronic attachment process.
Oscillator Strength Measurements in the Vacuum-Ultraviolet by the Emission Method
Authors: Goldbach C. , Nollez G.
Published: July 2016

The principles and the realization of an experiment devoted to oscillator strength measurements in the vacuum-ultraviolet by the emission method are briefly presented. The results obtained for the strong multiplets of neutral nitrogen and carbon in the 1200-2000 Å range yield an absolute scale of oscillator strengths in good agreement with the most recent calculations.
Diagnostics of Gold Laser Plasmas
Authors: Gauthier J.C. , Geindre J.P. , Monier P. , Chenais-Popovics C. , Tragin N. , Klapisch M. , Bar-Shalom A.
Published: July 2016

In order to achieve a nickel-like X ray laser scheme we need a tool to determine the parameters which characterise the high-Z plasma. The aim of this work is to study gold laser plasmas and to compare experimental results to a collisional-radiative model which describes nickel-like ions. The electronic temperature and density are measured by the emission of an aluminium tracer. They are compared to the predictions of the nickel-like model for pure gold. The results show that the density and temperature can be estimated in a pure gold plasma.
XUV Emission Features from the Livermore Soft X-Ray Laser Experiments
Authors: Eckart M.J. , Scofield J.H. , Hazi A.U.
Published: July 2016

The measured wavelengths in the soft x-ray region for 3p to 3s and 3d to 3p transitions in neon-, sodium-, and magnesium-like selenium are presented. The experimental results for the neon-like ions are compared to theoretical wavelength values and with values extrapolated along the isoelectronic sequence. The ions were contained in a plasma heated in a line-focus of a Nd-glass laser. The measurements were made with a time-gated microchannel-plate-intensified grazing incidence spectrograph.
The Dynamical State of the Atmosphere of the Supergiant Alpha Cygni (A2 Iae) Derived from High-Resolution Ultraviolet Spectra
Authors: Boer B. , de Jager C. , Nieuwenhuijzen H.
Published: July 2016

In order to study the apparent near instability of supergiant atmospheres high-resolution (λ/Δ λ = 8×104) BUSS (Balloon-borne Ultraviolet Stellar Spectrometer) spectra of the supergiant Alpha Cyg have been investigated. Equivalent widths of lines yield the variation of the line-of-sight microturbulent velocity component ζµwith optical depth τ. We find at τ5= 0.1: ζµequal to the velocity of sound. The consequent turbulent acceleration is directed outward, it increases outward and is about half the effective acceleration at τ5= 0.01. The macroturbulent velocity profile is double peaked with up- and downward velocities of 14 km s−1. We suggest that these motions are stochastic pulsations of large elements. At any time there are 30 to 40 such elements on the visible disk.
Optical Shop Testing of Liquid Mirrors
Authors: Borra E.F. , Beauchemin M. , Arsenault R. , Lalande R.
Published: July 2016

Borra (1982) has argued that it is scientifically useful and technically feasible to build very large optical telescopes (diameters over 15 meters) having as primary mirror a rotating container filled with mercury. We report here the results of various optical tests on prototype liquid mirrors. The results are very encouraging and seem to indicate that large liquid mirrors are feasible.
A Method to Estimate Fried's Seeing Parameter from a Time Series of Arbitrary Resolved Structures Imaged Through the Atmosphere
Authors: von der Lühe O.
Published: July 2016

One of the major fields of application of speckle-interferometric and speckle-imaging techniques is the photometry of astronomical objects exhibiting structure smaller than the seeing limit. The accuracy of the photometry depends critically on the accuracy to which the modulation transfer function (MTF), that describes the atmospheric-telescopic attenuation of the Fourier amplitudes of the object under consideration, is known. The estimation of the effective MTF is especially difficult when no known reference object is within the field of view.

A method is presented that allows to estimate the effective MTF from the observation of arbitrary structure with the use of FRIED-KORFF theory. The ratio of the squared modulus of the average Fourier transform and the average power spectrum serves as an estimator for the FRIED parameter r0. To a first approximation, this ratio is independent from the observed object. Additionally, the behaviour of the ratio in regions beyond the seeing limit in the Fourier plane may be analyzed to obtain an estimate of the speckle interferometry signal-to-noise ratio. The basic concept of the ratio method will be described, its accuracy will be discussed. First results on the application of the ratio method to observations of solar granulation will be presented.
Speckle Interferometry, Speckle Masking, Speckle Spectroscopy and Speckle Frame Selection
Authors: Weigelt Gerd
Published: July 2016

High-resolution speckle imaging is one of the most fascinating possibilities of a Very Large Telescope (VLT). Various speckle methods can yield a resolution of about 0.01" with a 8-m to 10-m VLT. As exiting as the resolution is the limiting magnitude of the speckle methods. The limiting magnitude is extremely seeingdependent. The following limiting magnitudes are possible with speckle interferometry, speckle masking and speckle spectroscopy:

4" seeing: limiting magnitude 15

2" seeing: limiting magnitude 17.5

1" seeing: limiting magnitude 20 (!)
Advanced Wide-Field Broad-Passband Refracting Field Correctors for Large Telescopes
Authors: Epps H.W. , Angel J.R.P. , Anderson E.
Published: July 2016

A preliminary 30-arcmin prime focus (f/2.0) refracting field corrector system for the University of California Ten-Meter Telescope (UC TMT) is presented which features 1/4-arcsec images containing more than 80% of the energy, over limited passbands within the wavelength range λ3300Å to λ1.0µ. Provision has been made in this system for an atmospheric dispersion corrector (ADC) but same has not yet been realized. Optical elements herein are small enough that this design could be scaled up to a Fifteen-Meter NNTT/SMT.

A compact 40-arcmin internal Cassegrain (f/1.75 hyperbola to f/5.0) broad-passband (λ3300Å to λ1.0µ) corrector, suitable for imaging and multi-object spectroscopy at the UC TMT, is presented which features 1/4-arcsec images containing more than 90% of the energy when averaged over field angle and color.

Three 60-arcmin external Cassegrain correctors for 300-inch f/1.8 and f/2.0 parabolic primary mirrors are presented which are suitable for a Fifteen-Meter NNTT/MMT. Image quality is comparable to the UC TMT Cassegrain corrector and it exceeds that of the UC TMT preliminary prime focus corrector system by a substantial margin. Each of these correctors contains an ADC which has been implemented in one example, eliminating 4.0 arcsec of differential atmospheric refraction with an rms residual of +/-0.10 arcsec over the broad passband (λ3300Å to λ1.0µ). A 60-arcmin external Cassegrain (f/1.8 extreme hyperbola to f/4.5) corrector with ADC yields yet a factor two in image quality but said hyperbolic primary mirror would be incompatible with angular field requirements in the thermal infrared.

A (300-inch) 40-arcmin external Cassegrain (f/1.0 parabola to f/4.0) broad-passband (λ3300Å to λ1.0µ) corrector with ADC is presented. Image quality is comparable to the previous Cassegrain correctors. The practicality of this design, together with recent advances in optical manufacturing capability of large, fast, nonspherical optics, suggests that relatively inexpensive compact telescopes of very large collecting area may be possible in the near future.
Prospects for Fibreoptics in Future Telescope Instrumentation
Authors: Lund Glenn
Published: July 2016

The importance and applied use of fibreoptics in astronomy has received rapidly growing attention in the past 5 years, particularly for instrumentation where the lightness, flexibility and simplicity of fibres, compared with classical optical systems, can be exploited to full advantage.

Angel and Angel et al, who seem to be the first to have used an optical fibre to link a telescope to an instrument, also made the first proposal for the construction of a VLT (FLOAT) consisting of 40 independent mirrors linked to a single instrument via optical fibres. Since that time many authors, including Connes, Serkowski et al, Hubbard et al, Heacox, Hill et al, Vanderriest, Courtes, Tubbs et al, Gray, Lund et al, Schiffer, Watson et al, Vanderriest et al, and Felenbock et al, have proposed or reported various applications involving fibres with astronomical instrumentation.
Cepheid-like Supergiants in the Halo
Authors: Sasselov D. D.
Published: July 2016

The newly proposed UU Her-type stars are discussed; their main features being long-period variability and high galactic latitude. It is unlikely that the UU Her stars originated in the plane of the galaxy as they are now located more than a kiloparsec above it. An alternative explanation of their normal Population I characteristics must be looked for.
The Effects of Convection in RR Lyrae Stars
Authors: Stellingwerf R. F.
Published: July 2016

The effect of convection in RR Lyrae stars has been investigated using nonlinear models that include the effects of time dependence, turbulent pressure, convective overshooting, and convection-pulsation interaction. The convective structure reduces to that of mixing-length theory in the limit of no time dependence and thick convective zones. Initial tests suggested that convection has an important effect on the stability and pulsation mode of these stars. We now have investigated the nonlinear nature of convection at limiting amplitude. Convection serves as a limiting amplitude mechanism for these stars by causing turbulence near the phase of minimum radius that damps the driving. A comparison with Geneva observations of RR Lyrae shows good agreement in the phase dependence and amplitude of the turbulent motions.
Identification of the (+2) Sequence of the CN Red System (A2Π-X2Σ) in Carbon Stars
Authors: Fujita Yoshio
Published: July 2016

Identification of spectral lines from λ7700 to λ8800 has been carried out in twenty-four carbon stars: AQ And, UU Aur, W CMa, Y CVn, X Cnc, ST Cas, WZ Cas, AX Cyg, RS Cyg, U Cyg, V 460 Cyg, RY Dra, UX Dra, BL Ori, W Ori, RX Peg, Z Psc, 19 Psc, S Set, Y Tau. VY UMa, HD 137613, HD 156074, and HD 182040. The spectrograms used for this purpose were obtained at the coude foci of spectrographs attached to 100-inch reflector of Mt. Wilson, 200-inch reflector of Mt. Palomar, and 74-inch reflector of Okayama. From the microphotometric tracings of each spectrogram, it was found that the main contributors to the spectral features of the region investigated are lines of the CN Red System (A2Π-X2Σ). and lines of the C2 Phillips system (b1Πu–x1Σg) are minor ones.
Perceived stress and quality of life in dementia patients and their caregiving spouses: does dyadic coping matter?
Authors: Häusler Andreas , Sánchez Alba , Gellert Paul , Deeken Friederike , Rapp Michael A. , Nordheim Johanna
Published: July 2016

Background:

Given the well-established association between perceived stress and quality of life (QoL) in dementia patients and their partners, our goal was to identify whether relationship quality and dyadic coping would operate as mediators between perceived stress and QoL.

Methods:

82 dyads of dementia patients and their spousal caregivers were included in a cross-sectional assessment from a prospective study. QoL was assessed with the Quality of Life in Alzheimer's Disease scale (QoL-AD) for dementia patients and the WHO Quality of Life-BREF for spousal caregivers. Perceived stress was measured with the Perceived Stress Scale (PSS-14). Both partners were assessed with the Dyadic Coping Inventory (DCI). Analyses of correlation as well as regression models including mediator analyses were performed.

Results:

We found negative correlations between stress and QoL in both partners (QoL-AD:r= −0.62; p < 0.001; WHO-QOL Overall:r= −0.27; p = 0.02). Spousal caregivers had a significantly lower DCI total score than dementia patients (p < 0.001). Dyadic coping was a significant mediator of the relationship between stress and QoL in spousal caregivers (z= 0.28; p = 0.02), but not in dementia patients. Likewise, relationship quality significantly mediated the relationship between stress and QoL in caregivers only (z= −2.41; p = 0.02).

Conclusions:

This study identified dyadic coping as a mediator on the relationship between stress and QoL in (caregiving) partners of dementia patients. In patients, however, we found a direct negative effect of stress on QoL. The findings suggest the importance of stress reducing and dyadic interventions for dementia patients and their partners, respectively.
Could the Substance Misuse of a Relative be an Important Factor for Those Seeking Help for Anxiety and Depression? A Preliminary Prevalence Study within Improving Access to Psychological Therapies (IAPT)
Authors: Newton Elizabeth , Shepherd Nicola , Orford Jim , Copello Alex
Published: July 2016

Background: The psychological difficulties and emotional impacts resulting from the substance use of close relatives constitute a large, underestimated and frequently unidentified health burden. The development of primary care mental health services in response to the Improving Access to Psychological Therapies initiative provides an opportunity to investigate this in more depth. Aims: A preliminary exploration of prevalence of IAPT service-users being treated for moderate-severe depression and/or anxiety who report that they have relatives with alcohol and/or drug problems. To explore the characteristics of the sample including comparison with those without a substance misusing relative. Method: One hundred service users completed a brief questionnaire. Routine data on depression and anxiety symptoms were accessed for the full consenting sample. Descriptive statistics were used to explore the family members of substance users and differences to the rest of the sample. Results: Twenty-two of the 100 IAPT service users reported having a close relative whose use of substances was of concern to them. The group with a relative who used substances were more depressed at the beginning of treatment than the rest of the sample. Conclusions: A significant number of people seeking psychological help for depression and anxiety within IAPT services reported being concerned about a close relative who misuses substances. They may be more distressed than those without a relative who misuses substances. Further exploration is warranted but preliminary findings indicate that this is an important research area with significant clinical implications.
Venus's Unexpected, Electrifying Water Loss
Authors: Zastrow Mark
Published: July 2016

New research shows that an electric field surrounding Venus is stripping its atmosphere of water—and the same phenomenon may plague exoplanets scientists hope might be habitable.
TWEAK favors phosphate-induced calcification of vascular smooth muscle cells through canonical and non-canonical activation of NFκB
Authors: Hénaut L , Sanz A B , Martin-Sanchez D , Carrasco S , Villa-Bellosta R , Aldamiz-Echevarria G , Massy Z A , Sanchez-Nino M D , Ortiz A
Published: July 2016

Vascular calcification (VC) is associated with increased cardiovascular mortality in aging, chronic kidney disease (CKD), type 2 diabetes mellitus (T2DM) and atherosclerosis. TNF-like weak inducer of apoptosis (TWEAK) recently emerged as a new biomarker for the diagnosis and prognosis of cardiovascular diseases. TWEAK binding to its functional receptor Fn14 was reported to promote several steps of atherosclerotic plaque progression. However, no information is currently available on the role of TWEAK/Fn14 on the development of medial calcification, which is highly prevalent in aging, CKD and T2DM. This study explored the involvement of TWEAK in human vascular smooth muscle cells (h-VSMCs) calcification in vitro. We report that TWEAK binding to Fn14 promotes inorganic phosphate-induced h-VSMCs calcification, favors h-VSMCs osteogenic transition, decreasing acta2 and myh11 and increasing bmp2 mRNA and tissue non-specific alkaline phosphatase (TNAP), and increases MMP9 activity. Blockade of the canonical NFκB pathway reduced by 80% TWEAK pro-calcific properties and decreased osteogenic transition, TNAP and MMP9 activity. Blockade of non-canonical NFκB signaling by a siRNA targeting RelB reduced by 20% TWEAK pro-calcific effects and decreased TWEAK-induced loss of h-VSMCs contractile phenotype and MMP9 activity, without modulating bmp2 mRNA or TNAP activity. Inhibition of ERK1/2 activation by a MAPK kinase inhibitor did not influence TWEAK pro-calcific properties. Our results suggest that TWEAK/Fn14 directly favors inorganic phosphate-induced h-VSMCs calcification by activation of both canonical and non-canonical NFκB pathways. Given the availability of neutralizing anti-TWEAK strategies, our study sheds light on the TWEAK/Fn14 axis as a novel therapeutic target in the prevention of VC.
Activation of salt-inducible kinase 2 promotes the viability of peritoneal mesothelial cells exposed to stress of peritoneal dialysis
Authors: Wang H-H , Lin C-Y , Su S-H , Chuang C-T , Chang Y-L , Lee T-Y , Lee S-C , Chang C-J
Published: July 2016

Maintaining mesothelial cell viability is critical to long-term successful peritoneal dialysis (PD) treatment. To clarify the viability mechanism of peritoneal mesothelial cells under PD solutions exposure, we examined the mechanisms of cellular response to this stress conditions. Here we report that the proteasome activity is inhibited when treated with PD solutions. Proteasome inhibition-mediated activation of salt-inducible kinase 2 (SIK2), an endoplasmic reticulum-resident protein, is important for mesothelial cell viability. SIK2 is mobilized to promote autophagy and protect the cells from apoptosis under PD solution or MG132 treatment. Immunofluorescence staining showed that SIK2 is colocalized with LC3B in the autophagosomes of mesothelial cells treated with PD solution or derived from patients undergoing PD treatment. SIK2 activation is likely via a two-step mechanism, upstream kinases relieving the autoinhibitory conformation of SIK2 molecule followed by autophosphorylation of Thr175 and activation of kinase activity. These results suggest that activation of SIK2 is required for the cell viability when proteasome activity is inhibited by PD solutions. Maintaining or boosting the activity of SIK2 may promote peritoneal mesothelial cell viability and evolve as a potential therapeutic target for maintaining or restoring peritoneal membrane integrity in PD therapy.
Epidemic spreading on complex networks with community structures
Authors: Stegehuis Clara , van der Hofstad Remco , van Leeuwaarden Johan S. H.
Published: July 2016

Many real-world networks display a community structure. We study two random graph models that create a network with similar community structure as a given network. One model preserves the exact community structure of the original network, while the other model only preserves the set of communities and the vertex degrees. These models show that community structure is an important determinant of the behavior of percolation processes on networks, such as information diffusion or virus spreading: the community structure can both enforce as well as inhibit diffusion processes. Our models further show that it is the mesoscopic set of communities that matters. The exact internal structures of communities barely influence the behavior of percolation processes across networks. This insensitivity is likely due to the relative denseness of the communities.
A novel role of microRNA 17-5p in the modulation of circadian rhythm
Authors: Gao Qian , Zhou Lan , Yang Su-Yu , Cao Ji-Min
Published: July 2016

The circadian clock helps living organisms to adjust their physiology and behaviour to adapt environmental day-night cycles. The period length of circadian rhythm reflects the endogenous cycle transition rate and is modulated by environmental cues or internal molecules and the latter are of substantial importance but remain poorly revealed. Here, we demonstrated that microRNA 17-5p (miR-17-5p), which has been associated with tumours, was an important factor in controlling the circadian period. MiR-17-5p was rhythmically expressed in synchronised fibroblasts and mouse master clock suprachiasmatic nuclei (SCN). MiR-17-5p and the gene Clock exhibited a reciprocal regulation: miR-17-5p inhibited the translation of Clock by targeting the 3′UTR (untranslated region) of Clock mRNA, whereas the CLOCK protein directly bound to the promoter of miR-17 and enhanced its transcription and production of miR-17-5p. In addition, miR-17-5p suppressed the expression of Npas2. At the cellular level, bidirectional changes in miR-17-5p or CLOCK resulted in CRY1 elevation. Accordingly, in vivo, both increase and decrease of miR-17-5p in the mouse SCN led to an increase in CRY1 level and shortening of the free-running period. We conclude that miR-17-5p has an important role in the inspection and stabilisation of the circadian-clock period by interacting with Clock and Npas2 and potentially via the output of CRY1.
Metabolomic analysis of percutaneous fine-needle aspiration specimens of thyroid nodules: Potential application for the preoperative diagnosis of thyroid cancer
Authors: Ryoo Inseon , Kwon Hyuknam , Kim Soo Chin , Jung Seung Chai , Yeom Jeong A , Shin Hwa Seon , Cho Hye Rim , Yun Tae Jin , Choi Seung Hong , Sohn Chul-Ho , Park Sunghyouk , Kim Ji-hoon
Published: July 2016

Thyroid nodules are a very common problem. Since malignant thyroid nodules should be treated surgically, preoperative diagnosis of thyroid cancer is very crucial. Cytopathologic analysis of percutaneous fine-needle aspiration (FNA) specimens is the current gold standard for diagnosing thyroid nodules. However, this method has led to high rates of inconclusive results. Metabolomics has emerged as a useful tool in medical fields and shown great potential in diagnosing various cancers. Here, we evaluated the potential of nuclear magnetic resonance (NMR) analysis of percutaneous FNA specimens for preoperative diagnosis of thyroid cancer. We analyzed metabolome of FNA samples of papillary thyroid carcinoma (n = 35) and benign follicular nodule (n = 69) using a proton NMR spectrometer. The metabolomic profiles showed a considerable discrimination between benign and malignant nodules. Receiver operating characteristic (ROC) curve analysis indicated that seven metabolites could serve as discriminators (area under ROC curve value, 0.64–0.85). These findings demonstrated that NMR analysis of percutaneous FNA specimens of thyroid nodules can be potentially useful in the accurate and rapid preoperative diagnosis of thyroid cancer.
Non-invasive evaluation of neuroprotective drug candidates for cerebral infarction by PET imaging of mitochondrial complex-I activity
Authors: Fukuta Tatsuya , Asai Tomohiro , Ishii Takayuki , Koide Hiroyuki , Kiyokawa Chiaki , Hashimoto Masahiro , Kikuchi Takashi , Shimizu Kosuke , Harada Norihiro , Tsukada Hideo , Oku Naoto
Published: July 2016

The development of a diagnostic technology that can accurately determine the pathological progression of ischemic stroke and evaluate the therapeutic effects of cerebroprotective agents has been desired. We previously developed a novel PET probe, 2-tert-butyl-4-chloro-5-{6-[2-(2-18F-fluoroethoxy)-ethoxy]-pyridin-3-ylmethoxy}-2H-pyridazin-3-one ([18F]BCPP-EF) for detecting activity of mitochondrial complex I (MC-I). This probe was shown to visualize neuronal damage in the living brain of rodent and primate models of neurodegenerative diseases. In the present study, [18F]BCPP-EF was applied to evaluate the therapeutic effects of a neuroprotectant, liposomal FK506 (FK506-liposomes), on cerebral ischemia/reperfusion (I/R) injury in transient middle cerebral artery occlusion rats. The PET imaging using [18F]BCPP-EF showed a prominent reduction in the MC-I activity in the ischemic brain hemisphere. Treatment with FK506-liposomes remarkably increased the uptake of [18F]BCPP-EF in the ischemic side corresponding to the improvement of blood flow disorders and motor function deficits throughout the 7 days after I/R. Additionally, the PET scan could diagnose the extent of the brain damage accurately and showed the neuroprotective effect of FK506-liposomes at Day 7, at which 2, 3, 5-triphenyltetrazolium chloride staining couldn’t visualize them. Our study demonstrated that the PET technology using [18F]BCPP-EF has a potent capacity to evaluate the therapeutic effect of drug candidates in living brain.
A Redox-Nucleophilic Dual-Reactable Probe for Highly Selective and Sensitive Detection of H2S: Synthesis, Spectra and Bioimaging
Authors: Zhang Changyu , Wang Runyu , Cheng Longhuai , Li Bingjie , Xi Zhen , Yi Long
Published: July 2016

Hydrogen sulfide (H2S) is an important signalling molecule with multiple biological functions. The reported H2S fluorescent probes are majorly based on redox or nucleophilic reactions. The combination usage of both redox and nucleophilic reactions could improve the probe’s selectivity, sensitivity and stability. Herein we report a new dual-reactable probe with yellow turn-on fluorescence for H2S detection. The sensing mechanism of the dual-reactable probe was based on thiolysis of NBD (7-nitro-1,2,3-benzoxadiazole) amine (a nucleophilic reaction) and reduction of azide to amine (a redox reaction). Compared with its corresponding single-reactable probes, the dual-reactable probe has higher selectivity and fluorescence turn-on fold with magnitude of multiplication from that of each single-reactable probe. The highly selective and sensitive properties enabled the dual-reactable probe as a useful tool for efficiently sensing H2S in aqueous buffer and in living cells.
Scattering engineering in continuously shaped metasurface: An approach for electromagnetic illusion
Authors: Guo Yinghui , Yan Lianshan , Pan Wei , Shao Liyang
Published: July 2016

The control of electromagnetic waves scattering is critical in wireless communications and stealth technology. Discrete metasurfaces not only increase the design and fabrication complex but also cause difficulties in obtaining simultaneous electric and optical functionality. On the other hand, discontinuous phase profiles fostered by discrete systems inevitably introduce phase noises to the scattering fields. Here we propose the principle of a scattering-harness mechanism by utilizing continuous gradient phase stemming from the spin-orbit interaction via sinusoidal metallic strips. Furthermore, by adjusting the amplitude and period of the sinusoidal metallic strip, the scattering characteristics of the underneath object can be greatly changed and thus result in electromagnetic illusion. The proposal is validated by full-wave simulations and experiment characterization in microwave band. Our approach featured by continuous phase profile, polarization independent performance and facile implementation may find widespread applications in electromagnetic wave manipulation.
Expression patterns, mutation detection and RNA interference of Rhopalosiphum padi voltage-gated sodium channel genes
Authors: Zuo Yayun , Peng Xiong , Wang Kang , Lin Fangfei , Li Yuting , Chen Maohua
Published: July 2016

The voltage-gated sodium channel (VGSC) is the target of sodium-channel-blocking insecticides. Traditionally, animals were thought to have only one VGSC gene comprising a α-subunit with four homologous domains (DI–DIV). The present study showed that Rhopalosiphum padi, an economically important crop pest, owned a unique heterodimeric VGSC (H1 and H2 subunits) encoded by two genes (Rpvgsc1 and Rpvgsc2), which is unusual in insects and other animals. The open reading frame (ORF) of Rpvgsc1 consisted 1150 amino acids, and the ORF of Rpvgsc2 had 957 amino acids. Rpvgsc1 showed 64.1% amino acid identity to DI–DII of Drosophila melanogaster VGSC and Rpvgsc2 showed 64.0% amino acid identity to DIII–DIV of D. melanogaster VGSC. A M918L mutation previously reported in pyrethroids-resistant strains of other insects was found in the IIS4-S6 region of R. padi field sample. The two R. padi VGSC genes were expressed at all developmental stages and showed similar expression patterns after treatment with beta-cypermethrin. Knockdown of Rpvgsc1 or Rpvgsc2 caused significant reduction in mortality rate of R. padi after exposure to beta-cypermethrin. These findings suggest that the two R. padi VGSC genes are both functional genes.