An evaluation of Skylab (EREP) remote sensing techniques applied to investigations of crustal structure

The author has identified the following significant results. Film positives (70mm) from all six S190A multispectral photographic camera stations for any one scene can be registered and analyzed in a color additive viewer. Using a multispectral viewer, S190A and B films can be projected directly onto published geologic and topographic maps at scales as large as 1:62,500 and 1:24,000 without significant loss of detail. S190A films and prints permit the detection of faults, fractures, and other linear features not visible in any other space imagery. S192 MSS imagery can be useful for rock-type discrimination studies and delineation of linear patterns and arcuate anomalies. Anomalous color reflectances and arcuate color patterns revealed mineralized zones, copper deposits, vegetation, and volcanic rocks in various locations such as Panamint Range (CA), Greenwater (Death Valley), Lava Mountains (CA), northwestern Arizona, and Coso Hot Springs (CA)

Simultaneous multiwavelength observations of V404 Cygni during its 2015 June outburst decay strengthen the case for an extremely energetic jet-base

We present results of multiband optical photometry of the black hole X-ray binary system V404 Cygni obtained using Wheaton College Observatory's 0.3m telescope, along with strictly simultaneous INTEGRAL and Swift observations during 2015 June 25.15--26.33 UT, and 2015 June 27.10--27.34 UT. These observations were made during the 2015 June outburst of the source when it was going through an epoch of violent activity in all wavelengths ranging from radio to $\gamma$-rays. The multiwavelength variability timescale favors a compact emission region, most likely originating in a jet outflow, for both observing epochs presented in this work. The simultaneous INTEGRAL/Imager on Board the Integral Satellite (IBIS) 20--40 keV light curve obtained during the June 27 observing run correlates very strongly with the optical light curve, with no detectable delay between the optical bands as well as between the optical and hard X-rays. The average slope of the dereddened spectral energy distribution was roughly flat between the $I_C$- and $V$-bands during the June 27 run, even though the optical and X-ray flux varied by $>$25$\times$ during the run, ruling out an irradiation origin for the optical and suggesting that the optically thick to optically thin jet synchrotron break during the observations was at a frequency larger than that of $V$-band, which is quite extreme for X-ray binaries. These observations suggest that the optical emission originated very close to the base of the jet. A strong H$\alpha$ emission line, probably originating in a quasi-spherical nebula around the source, also contributes significantly in the $R_C$-band. Our data, in conjunction with contemporaneous data at other wavelengths presented by other groups, strongly suggest that the jet-base was extremely compact and energetic during this phase of the outburst.Comment: 15 pages, 2 tables, 5 figures. Accepted for publication in Ap

Atomic Deuterium Adsorbed on the Surface of Liquid Helium

We investigate deuterium atoms adsorbed on the surface of liquid helium in equilibrium with a vapor of atoms of the same species. These atoms are studied by a sensitive optical method based on spectroscopy at a wavelength of 122 nm, exciting the 1S-2P transition. We present a direct measurement of the adsorption energy of deuterium atoms on helium and show evidence for the existence of resonantly enhanced recombination of atoms residing on the surface to molecules.Comment: 6 pages 4 figure

On variability and spectral distortion of the fluorescent iron lines from black-hole accretion discs

We investigate properties of iron fluorescent line arising as a result of illumination of a black hole accretion disc by an X-ray source located above the disc surface. We study in details the light-bending model of variability of the line, extending previous work on the subject. We indicate bending of photon trajectories to the equatorial plane, which is a distinct property of the Kerr metric, as the most feasible effect underlying reduced variability of the line observed in several objects. A model involving an X-ray source with a varying radial distance, located within a few central gravitational radii around a rapidly rotating black hole, close to the disc surface, may explain both the elongated red wing of the line profile and the complex variability pattern observed in MCG--6-30-15 by XMM-Newton. We point out also that illumination by radiation which returns to the disc (following the previous reflection) contributes significantly to formation of the line profile in some cases. As a result of this effect, the line profile always has a pronounced blue peak (which is not observed in the deep minimum state in MCG--6-30-15), unless the reflecting material is absent within the innermost 2--3 gravitational radii.Comment: 24 pages, 22 figures. Accepted for publication in MNRA

Suzaku observations of Markarian 335: evidence for a distributed reflector

We report on a 151 ks net exposure Suzaku observation of the Narrow Line Seyfert 1 galaxy Mrk 335. The 0.5-40 keV spectrum contains a broad Fe line, a strong soft excess below about 2 keV and a Compton hump around 20-30 keV. We find that a model consisting of a power law and two reflectors provides the best fit to the time-averaged spectrum. In this model, an ionized, heavily blurred, inner reflector produces most of the soft excess, while an almost neutral outer reflector (outside ~40 r_g) produces most of the Fe line emission. The spectral variability of the observation is characterised by spectral hardening at very low count rates. In terms of our power-law + two-reflector model it seems like this hardening is mainly caused by pivoting of the power law. The rms spectrum of the entire observation has the curved shape commonly observed in AGN, although the shape is significantly flatter when an interval which does not contain any deep dip in the lightcurve is considered. We also examine a previous 133 ks XMM-Newton observation of Mrk 335. We find that the XMM-Newton spectrum can be fitted with a similar two-reflector model as the Suzaku data and we confirm that the rms spectrum of the observation is flat. The flat rms spectra, as well as the high-energy data from the Suzaku PIN detector, disfavour an absorption origin for the soft excess in Mrk 335.Comment: 13 pages, 13 figures. Accepted for publication in MNRA

On The Reddening in X-ray Absorbed Seyfert 1 Galaxies

There are several Seyfert galaxies for which there is a discrepancy between the small column of neutral hydrogen deduced from X-ray observations and the much greater column derived from the reddening of the optical/UV emission lines and continuum. The standard paradigm has the dust within the highly ionized gas which produces O~VII and O~VIII absorption edges (i.e., a ``dusty warm absorber''). We present an alternative model in which the dust exists in a component of gas in which hydrogen has been stripped, but which is at too low an ionization state to possess significant columns of O~VII and O~VIII (i.e, a ``lukewarm absorber''). The lukewarm absorber is at sufficient radial distance to encompass much of the narrow emission-line region, and thus accounts for the narrow-line reddening, unlike the dusty warm absorber. We test the model by using a combination of photoionization models and absorption edge fits to analyze the combined ROSAT/ASCA dataset for the Seyfert 1.5 galaxy, NGC 3227. We show that the data are well fit by a combination of the lukewarm absorber and a more highly ionized component similar to that suggested in earlier studies. We predict that the lukewarm absorber will produce strong UV absorption lines of N V, C IV, Si IV and Mg II. Finally, these results illustrate that singly ionized helium is an important, and often overlooked, source of opacity in the soft X-ray band (100 - 500 eV).Comment: 17 pages, Latex, includes 1 figure (encapsulated postscript), one additional table in Latex (landscape format), to appear in the Astrophysical Journa

Sinking properties of some phytoplankton shapes and the relation of form resistance to morphological diversity of plankton – an experimental study

Form resistance (Phi) is a dimensionless number expressing how much slower or faster a particle of any form sinks in a fluid medium than the sphere of equivalent volume. Form resistance factors of PVC models of phytoplankton sinking in glycerin were measured in a large aquarium (0.6 x 0.6 x 0.95 m). For cylindrical forms, a positive relationship was found between Phi and length/ width ratio. Coiling decreased Phi in filamentous forms. Form resistance of Asterionella colonies increased from single cells up to 6-celled colonies than remained nearly constant. For Fragilaria crotonensis chains, no such upper limit to Phi was observed in chains of up to 20 cells ( longer ones were not measured). The effect of symmetry on Phi was tested in 1 - 6-celled Asterionella colonies, having variable angles between the cells, and in Tetrastrum staurogeniaeforme coenobia, having different spine arrangements. In all cases, symmetric forms had considerably higher form resistance than asymmetric ones. However, for Pediastrum coenobia with symmetric/asymmetric fenestration, no difference was observed with respect to symmetry. Increasing number and length of spines on Tetrastrum coenobia substantially increased Phi. For a series of Staurastrum forms, a significant positive correlation was found between arm-length/cell-width ratio and Phi: protuberances increased form resistance. Flagellates (Rhodomonas, Gymnodinium) had a Phi 1. The highest value ( Phi = 8.1) was established for a 20-celled Fragilaria crotonensis chain. Possible origin of the so-called 'vital component' ( a factor that shows how much slower viable populations sink than morphologically similar senescent or dead ones) is discussed, as is the role of form resistance in evolution of high diversity of plankton morphologies

Truncated Levy Random Walks and Generalized Cauchy Processes

A continuous Markovian model for truncated Levy random walks is proposed. It generalizes the approach developed previously by Lubashevsky et al. Phys. Rev. E 79, 011110 (2009); 80, 031148 (2009), Eur. Phys. J. B 78, 207 (2010) allowing for nonlinear friction in wondering particle motion and saturation of the noise intensity depending on the particle velocity. Both the effects have own reason to be considered and individually give rise to truncated Levy random walks as shown in the paper. The nonlinear Langevin equation governing the particle motion was solved numerically using an order 1.5 strong stochastic Runge-Kutta method and the obtained numerical data were employed to calculate the geometric mean of the particle displacement during a certain time interval and to construct its distribution function. It is demonstrated that the time dependence of the geometric mean comprises three fragments following one another as the time scale increases that can be categorized as the ballistic regime, the Levy type regime (superballistic, quasiballistic, or superdiffusive one), and the standard motion of Brownian particles. For the intermediate Levy type part the distribution of the particle displacement is found to be of the generalized Cauchy form with cutoff. Besides, the properties of the random walks at hand are shown to be determined mainly by a certain ratio of the friction coefficient and the noise intensity rather then their characteristics individually.Comment: 7 pages, 3 figure

Utility of a routine ultrasound for detection of ectopic pregnancies among women requesting abortion:A retrospective review

INTRODUCTION: Routine ultrasound may be used in abortion services to determine gestational age and confirm an intrauterine pregnancy. However, ultrasound adds complexity to care and results may be inconclusive, delaying abortion. We sought to determine the rate of ectopic pregnancy and the utility of routine ultrasound in its detection, in a community abortion service. METHODS: Retrospective case record review of women requesting abortion over a 5-year period (2015–2019) with an outcome of ectopic pregnancy or pregnancy of unknown location (PUL) at a service (Edinburgh, UK) conducting routine ultrasound on all women. Records were searched for symptoms at presentation, development of symptoms during clinical care, significant risk factors and routine ultrasound findings. RESULTS: Only 29/11 381 women (0.25%, 95% CI 0.18%, 0.33%) had an ectopic pregnancy or PUL (tubal=18, caesarean scar=1, heterotopic=1, PUL=9). Eleven (38%) cases had either symptoms at presentation (n=8) and/or significant risk factors for ectopic pregnancy (n=4). A further 12 women developed symptoms during their clinical care. Of the remaining six, three were PUL treated with methotrexate and three were ectopic (salpingectomy=2, methotrexate=1). In three cases, the baseline ultrasound indicated a probable early intrauterine pregnancy. CONCLUSIONS: Ectopic pregnancies are uncommon among women presenting for abortion. The value of routine ultrasound in excluding ectopic pregnancy in symptom-free women without significant risk factors is questionable as it may aid detection of some cases but may provide false reassurance that a pregnancy is intrauterine

In-situ measurements of the optical absorption of dioxythiophene-based conjugated polymers

Conjugated polymers can be reversibly doped by electrochemical means. This doping introduces new sub-bandgap optical absorption bands in the polymer while decreasing the bandgap absorption. To study this behavior, we have prepared an electrochemical cell allowing measurements of the optical properties of the polymer. The cell consists of a thin polymer film deposited on gold-coated Mylar behind which is another polymer that serves as a counterelectrode. An infrared transparent window protects the upper polymer from ambient air. By adding a gel electrolyte and making electrical connections to the polymer-on-gold films, one may study electrochromism in a wide spectral range. As the cell voltage (the potential difference between the two electrodes) changes, the doping level of the conjugated polymer films is changed reversibly. Our experiments address electrochromism in poly(3,4-ethylene-dioxy-thiophene) (PEDOT) and poly(3,4-dimethyl-propylene-dioxy-thiophene) (PProDOT-Me$_2$). This closed electrochemical cell allows the study of the doping induced sub-bandgap features (polaronic and bipolaronic modes) in these easily oxidized and highly redox switchable polymers. We also study the changes in cell spectra as a function of polymer thickness and investigate strategies to obtain cleaner spectra, minimizing the contributions of water and gel electrolyte features