A Catalog of Digital Images of 113 Nearby Galaxies

We present a digital catalog of images of 113 galaxies in this paper. These galaxies are all nearby, bright, large and well resolved. All images were recorded with charge coupled devices (CCDs) at the Palomar Observatory with the 1.5 meter telescope and at the Lowell Observatory with the 1.1 meter telescope. At Palomar we used the Thuan--Gunn g, r and i photometric bands to take 3 images each of 31 spiral galaxies; at Lowell we used the B_J and R bands (2 images per galaxy) of the photometric system by Gullixson et al. (1995) to observe 82 spirals and ellipticals. The galaxies were selected to span the Hubble classification classes. All data are photometrically calibrated with foreground stars removed. Important data on these galaxies published in the "Third Reference Catalog of Bright Galaxies" (RC3) are recorded in the FITS file headers. All files are available through anonymous FTP from ftp://astro.princeton.edu/, through WWW at http://astro.princeton.edu/~frei/galaxy_catalog.html, and Princeton University Press will soon publish the data on CD-ROM.Comment: uuencoded compressed tar archive of postscript files (paper + 2 tables + 7 figures) Accepted for publication in the Astronomical Journa

An information states blackboard as an intelligent querying interface for snow and avalanche data

We present the graph-based querying paradigm used in the Regional Avalanche Information and Forecasting System (RAIFoS) for the collection and analysis of snow and weather related physical parameters in the Swiss Alps. The querying paradigm relies upon the issue of interactively constructing a semantically valid query graph on an Information States Blackboard as guided by meta-data elements standing for interpretations of conceptual model, data values and/or operations. The meta-data elements constitute the terms of a meta-data-driven query language (MDDQL) the interpretation of which is done interactively relying on a kind of finite state automaton

Attached and separated rotating flow over a finite height ridge

This article discusses the effect of rotation on the boundary layer in high Reynolds number flow over a ridge using a numerical method based on stabilized finite elements that captures steady solutions up to a Reynolds number of order 10^6. The results are validated against boundary layer computations in shallow flows and for deep flows against experimental observations reported in Machicoane et al. [Phys. Rev. Fluids 3, 034801 (2018)]. In all cases considered the boundary layer remains attached, even at arbitrarily large Reynolds numbers, provided the Rossby number of the flow is less than some critical Rossby number of order unity. At any fixed Rossby number larger than this critical value, the flow detaches at sufficiently high Reynolds number to form a steady recirculating region in the lee of the ridge. At even higher Reynolds numbers no steady flow is found. This disappearance of steady solutions closely reproduces the transition to unsteadiness seen in the laboratory

Induction of somatic mutation and recombination by four inhibitors of eukaryotic topoisomerases assayed in the wing spot test of Drosophila melanogaster

Four inhibitors of eukaryotic topoisomerases were investigated for genotoxic effects in the wing spot test of Drosophila melanogaster. As a somatic mutation and recombination test (SMART) this assay assesses mitotic recombination and mutational events of various kinds. We studied camptothecin as a topoisomerase I inhibitor, as well as ellipticine as an intercalating inhibitor and teniposide and etoposide as two non-intercalating inhibitors of topoisomerase II. Wing spots were induced in flies trans-heterozygous for the recessive wing cell markers multiple wing hairs (mwh) and flare (flr3) as well as in flies heterozygous for mwh and the multiply inverted TM3 balancer chromosome. All four compounds proved significantly genotoxic in this test The spot induction frequencies formally standardized to the millimolar unit of exposure dose decreased in the order camptothecin > teniposide > ellipticine ≳ etoposide in the mwh/flr3 inversion-free genotype. In the mwh/TM3 genotype, in which mitotic crossing over is suppressed because of the inversion-heterozygosity, the observed spot frequencies were considerably reduced, but to different extents. In this genotype, spot induction by ellipticine was not statistically significant, and it was determined that >99% of the spots are due to mitotic recombination in mwh/flr3 flies. For the other compounds, spot induction in the inversion-heterozygous genotype was significant. The relative contribution of recombination to total spot induction in the inversion-free genotype was 88% for camptothecin. It was significantly lower for the two epipodophyllotoxins teniposide (71%) and etoposide (59%). Only suggestions can be proffered at present as to how these proportions could be related to the primary damage produced by the respective compounds on the chromosome

Mantle heterogeneity during the formation of the North Atlantic Igneous Province: Constraints from trace element and Sr-Nd-Os-O isotope systematics of Baffin Island picrites

Sr-Nd-Os-O isotope and major and trace element data from ~62 Ma picrites from Baffin Island constrain the composition of mantle sources sampled at the inception of North Atlantic Igneous Province (NAIP) magmatism. We recognize two compositional types. Depleted (N-type) lavas have low 87Sr/86Sri (0.702990–0.703060) and 187Os/188Osi (0.1220–0.1247) and high 143Nd/144Ndi (0.512989–0.512999) and are depleted in incompatible elements relative to primitive mantle. Enriched (E-type) lavas have higher 87Sr/86Sri (0.703306–0.703851) and 187Os/188Osi (0.1261–0.1303), lower 143Nd/144Ndi (0.512825–0.512906), and incompatible element concentrations similar to, or more enriched than, primitive mantle. There is also a subtle difference in oxygen isotope composition; E-type lavas are marginally lower in δ18Oolivine value (5.16–4.84‰) than N-type lavas (5.15–5.22‰). Chemical and isotopic variations between E- and N-type lavas are inconsistent with assimilation of crust and/or subcontinental lithospheric mantle and appear to instead reflect mixing between melts derived from two distinct mantle sources. Strontium-Nd-O isotope compositions and incompatible trace element abundances of N-type lavas suggest these are largely derived from the depleted upper mantle. The 187Os/188Osi ratios of N-type lavas can also be explained by such a model but require that the depleted upper mantle had γOs of approximately −5 to −7 at 62 Ma. This range overlaps the lowest γOs values measured in abyssal peridotites. Baffin Island lava compositions are also permissive of a model involving recharging of depleted upper mantle with 3He-rich material from the lower mantle (Stuart et al., Nature, 424, 57–59, 2003), with the proviso that recharge had no recognizable effect on the lithophile trace element and Sr-Nd-Os-O isotope composition. The origin of the enriched mantle component sampled by Baffin Island lavas is less clear but may be metasomatized and high-temperature-altered recycled oceanic lithosphere transported within the proto Iceland plume. Differences between Baffin Island lavas and modern Icelandic basalts suggest that a range of enriched and depleted mantle sources have been tapped since the inception of magmatism in the province. Similarities between Baffin Island lavas erupted and those of similar age from East and West Greenland also suggest that the enriched component in Baffin Island lavas may have been sampled by lavas erupted over a wide geographic range

Vinogradov's three primes theorem with primes having given primitive roots

The first purpose of our paper is to show how Hooley's celebrated method leading to his conditional proof of the Artin conjecture on primitive roots can be combined with the Hardy-Littlewood circle method. We do so by studying the number of representations of an odd integer as a sum of three primes, all of which have prescribed primitive roots. The second purpose is to analyse the singular series. In particular, using results of Lenstra, Stevenhagen and Moree, we provide a partial factorisation as an Euler product and prove that this does not extend to a complete factorisation

Ambiguity-Free Method for Fast and Precise GNSS Differential Positioning

Methods based on integer ambiguity determination, such as the least-squares ambiguity decorrelation adjustment (LAMBDA) method, are currently used for precise global navigation satellite system (GNSS) differential positioning. In the present paper, the author proposes an ambiguity-free method based on a dedicated mixed (stochastic/deterministic) optimization algorithm that, unlike the LAMBDA method, is capable of providing reliable and accurate results using few observation epochs (e.g., 1-cm accuracy with just two epochs), having the additional advantages of insensitivity to cycle slips and impossibility of wrong ambiguity fixation. In addition, it is demonstrated that the application of the linear (deterministic) part of this algorithm yields the correct baseline results much more easily and quickly than methods requiring integer ambiguity determination, provided the initial approximate coordinates are accurate to a few centimeters. However, the use of ambiguity-free methods requires that the integer character of the ambiguities be preserved so that they can be eliminated; therefore no ionosphere-free combination can be computed and the methods are valid only for short baselines (e.g., less than 10 km).Baselga Moreno, S. (2014). Ambiguity-Free Method for Fast and Precise GNSS Differential Positioning. Journal of Surveying Engineering. 140(1):22-27. doi:10.1061/(ASCE)SU.1943-5428.0000111S2227140

Eulerian time-stepping schemes for the non-stationary Stokes equations on time-dependent domains

This article is concerned with the discretisation of the Stokes equations on time- dependent domains in an Eulerian coordinate framework. Our work can be seen as an extension of a recent paper by Lehrenfeld and Olshanskii (ESAIM: M2AN 53(2):585–614, 2019), where BDF-type time-stepping schemes are studied for a parabolic equation on moving domains. For space discretisation, a geometrically unfit- ted finite element discretisation is applied in combination with Nitsche’s method to impose boundary conditions. Physically undefined values of the solution at previous time-steps are extended implicitly by means of so-called ghost penalty stabilisations. We derive a complete a priori error analysis of the discretisation error in space and time, including optimal L2(L2)-norm error bounds for the velocities. Finally, the theoretical results are substantiated with numerical examples

The non-destructive study of museums objects by means of neutrons imaging methods and results of investigations

Based on experience from many kinds of investigations with neutron imaging methods (radiography, tomography, time-dependent studies) and in comparison to conventional X-ray methods, the authors discuss the potential of future improved studies for cultural-heritage purposes. Whereas the focus of the paper is on the imaging aspect, other established techniques as neutron activation analysis (NAA), prompt gamma activation analysis (PGAA), neutron-induced autoradiography and neutron scattering are mentioned too. Although a great potential for studies similar to those described in the paper exists, a considerable effort is needed to define the best-suited methods for the dedicated cultural historical request. A real barrier between the experts at large research facilities (as, e.g., neutron sources are) and the partners from the museums side has to be overcome in order to solve the problems. A joint European approach will help in this respect