1,090 research outputs found

    Surveyor spacecraft system - Surveyor 6 flight performance Final report

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    Surveyor 6 spacecraft flight performance characteristics, including data on television equipment, alpha scattering experiment, and powered flight translatio

    Two New Species and Temporal Changes in the Prevalence of Eimerians in a Free-Living Population of Townsend\u27s Ground Squirrels (\u3ci\u3eSpermophilus townsendii\u3c/i\u3e) in Idaho

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    More than 1,180 fecal samples were collected from 253 juvenile and 384 adult Townsend\u27s ground squirrels (Spermophilus townsendii) at the Snae Snake River Birds of Prey Area near Boise, Idaho, from February to June 1992. Oocysts of 7 eimerians were observed. Five are new host records (Eimeria beecheyi, Eimeria bilamellata, Eimeria callospermophili, Eimeria lateralis, and Eimeria morainensis), 2 species are described here as new, and new structural information on E. morainensis is added. Sporulated oocysts of Eimeria adaensis n. sp. are ovoidal, 19.6 x 22.7 (16-22 x 18-26) μm with sporocysts ellipsoidal 7.2 x 11.9 (6-10 x 9-15) μm. No micropyle or oocyst residuum, but polar bodies, Stieda bodies, and sporocyst residua are present. Sporulated oocysts of Eimeria pseudospermophili n. sp. are ovoidal, 24.7 x 28.5 (21-27 x 25-32) μm with sporocysts ellipsoidal 8.8 x 14.2 (8-10 x 12-17) μm. Micropyle and oocyst residuum are absent, but polar bodies and Stieda bodies are present. Sporulated oocysts of E. morainensis are more variable in size and shape than originally described and contain 2 distinctly different residua not previously described. Temporal changes in the prevalence of eimerians of all 7 species combined in adult squirrels showed significant decline (r2 = 0.79, P \u3c 0.001). We hypothesize that this decline was due to drought during the period of squirrel activity. No significant temporal change in the prevalence of eimerians in juvenile squirrels was observed. The prevalence of E. callospermophili, E. adaensis, and all eimerians combined in adults was significantly greater than in juveniles. There was no significant difference in eimerian prevalence between male and female squirrels (P \u3c 0.05)

    Teaching during COVID-19: Relational-Cultural Theory in the Online Classroom

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    The sudden conversion from face-to-face to online instruction in Spring semester 2020 due to the COVID-19 pandemic was unprecedented. During this time instructors in helping professional training programs were engaged in the duality of being impacted in various degrees while simultaneously training students to assist clients in dealing with the resulting stress and emotional impact. Relational-Cultural Theory (RCT) is a framework that can be used within online counselor education to consider the impact of the larger socio-cultural context on student learning, prioritizing fostering relational connections. In this article, online teaching approaches aligned with the video conferencing tool, Zoom, are described

    Mass and Angular Momentum Transfer in the Massive Algol Binary RY Persei

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    We present an investigation of H-alpha emission line variations observed in the massive Algol binary, RY Per. We give new radial velocity data for the secondary based upon our optical spectra and for the primary based upon high dispersion UV spectra. We present revised orbital elements and an estimate of the primary's projected rotational velocity (which indicates that the primary is rotating 7 times faster than synchronous). We use a Doppler tomography algorithm to reconstruct the individual primary and secondary spectra in the region of H-alpha, and we subtract the latter from each of our observations to obtain profiles of the primary and its disk alone. Our H-alpha observations of RY Per show that the mass gaining primary is surrounded by a persistent but time variable accretion disk. The profile that is observed outside-of-eclipse has weak, double-peaked emission flanking a deep central absorption, and we find that these properties can be reproduced by a disk model that includes the absorption of photospheric light by the band of the disk seen in projection against the face of the star. We developed a new method to reconstruct the disk surface density distribution from the ensemble of H-alpha profiles observed around the orbit, and this method accounts for the effects of disk occultation by the stellar components, the obscuration of the primary by the disk, and flux contributions from optically thick disk elements. The resulting surface density distribution is elongated along the axis joining the stars, in the same way as seen in hydrodynamical simulations of gas flows that strike the mass gainer near trailing edge of the star. This type of gas stream configuration is optimal for the transfer of angular momentum, and we show that rapid rotation is found in other Algols that have passed through a similar stage.Comment: 39 pages, 12 figures, ApJ in press, 2004 June 20 issu

    Three-dimensional topologically gauged N=6 ABJM type theories

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    In this paper we construct the N=6\mathcal N=6 conformal supergravity in three dimensions from a set of Chern-Simons-like terms one for each of the graviton, gravitino, and R-symmetry gauge field and then couple this theory to the N=6\mathcal N=6 superconformal ABJM theory. In a first step part of the coupled Lagrangian for this topologically gauged ABJM theory is derived by demanding that all terms of third and second order in covariant derivatives cancel in the supersymmtry variation of the Lagrangian. To achieve this the transformation rules of the two separate sectors must be augmented by new terms. In a second step we analyze all terms in δL\delta L that are of first order in covariant derivatives. The cancelation of these terms require additional terms in the transformation rules as well as a number of new terms in the Lagrangian. As a final step we check that all remaining terms in δL\delta L which are bilinear in fermions cancel which means that the presented Lagrangian and transformation rules constitute the complete answer. In particular we find in the last step new terms in the scalar potential containing either one or no structure constant. The non-derivative higher fermion terms in δL\delta L that have not yet been completely analyzed are briefly discussed.Comment: 26 pages, v.2 minor corrections, comment on relation to chiral gravity added

    An XMM-Newton observation of the nova-like variable UX UMa: spatially and spectrally resolved two-component X-ray emission

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    In the optical and ultraviolet regions of the electromagnetic spectrum, UX Ursae Majoris is a deeply eclipsing cataclysmic variable. However, no soft X-ray eclipse was detected in ROSAT observations. We have obtained a 38 ksec XMM-Newton observation to further constrain the origin of the X-rays. The combination of spectral and timing information allows us to identify two components in the X-ray emission of the system. The soft component, dominant below photon energies of 2 keV, can be fitted with a multi-temperature plasma model and is uneclipsed. The hard component, dominant above 3 keV, can be fitted with a kT ~ 5 keV plasma model and appears to be deeply eclipsed. We suggest that the most likely source of the hard X-ray emission in UX UMa, and other systems in high mass transfer states, is the boundary layer.Comment: To appear in MNRAS Letter

    Quantum Holonomy in Three-dimensional General Covariant Field Theory and Link Invariant

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    We consider quantum holonomy of some three-dimensional general covariant non-Abelian field theory in Landau gauge and confirm a previous result partially proven. We show that quantum holonomy retains metric independence after explicit gauge fixing and hence possesses the topological property of a link invariant. We examine the generalized quantum holonomy defined on a multi-component link and discuss its relation to a polynomial for the link.Comment: RevTex, 12 pages. The metric independence of path integral measure is justified and the case of multi-component link is discussed in detail. To be published in Physical Review

    Discovery of a cataclysmic variable with a sub-stellar companion

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    We find that the ROSAT source 1RXS J105010.3-140431 is a cataclysmic variable with orbital period of 88.6 minutes and a spectrum closely resembling WZ Sge. In particular, emission lines are flanked by Stark-broadened absorption wings probably originating in the photosphere of a compact object. The Balmer absorption lines can be modeled by the spectrum of a DA white dwarf with 13 000 <Teff<< T_{eff} < 24 000 K. The strong absorption lines allowed us to obtain direct radial velocities of the white dwarf using the cross-correlation technique. We find an extremely low white dwarf radial velocity half amplitude, KwdK_{wd} = 4 ±\pm 1 km s1^{-1}. This is consistent with the upper limit obtained from the Hα\alpha emission line wing K < 20 km s1^{-1}. The corresponding mass function is incompatible with a main sequence secondary, but is compatible with a post orbital period minimum cataclysmic variable with a brown dwarf-like secondary. The formal solution gives a secondary mass of 10-20 jovian masses. Doppler maps for the emission lines and the hypothesis of black-body emission indicate a steady state (T r3/4\sim r^{-3/4}) accretion disk mainly emitting in Hα\alpha and an optically thicker hotspot with a strong contribution to the higher order Balmer lines and \ion{He}{I} 5875. As in other long cycle length dwarf novae, evidence for inner disk removal is found from the analysis of the emission lines.Comment: 14 figures, 2 of them composed. Total 20 figures. Accepted for publication in Astronomy and Astrophysic

    Multiwavelength Monitoring of the Narrow-Line Seyfert 1 Galaxy Akn 564. II. Ultraviolet Continuum and Emission-line Variability

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    We present results of an intensive two-month campaign of approximately daily spectrophotometric monitoring of the narrow-line Seyfert 1 galaxy Akn 564 with HST. The fractional variability amplitude of the continuum variations between 1365-3000 A is ~6%, about a factor 3 less than that found in typical Seyfert 1 galaxies over a similar period of time. However, large amplitude, short time-scale flaring behavior is evident, with trough-to-peak flux changes of about 18% in approximately 3 days. We present evidence for wavelength-dependent continuum time delays, with the variations at 3000 A lagging behind those at 1365 A by about 1 day. These delays may be interpreted as evidence for a stratified continuum reprocessing region, possibly an accretion-disk structure. The Lyman-alpha 1216 emission-line exhibits flux variations of about 1% amplitude.Comment: 27 pages, 14 figures. Accepted by Astrophysical Journa
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