The VizieR database of Astronomical Catalogues

VizieR is a database grouping in an homogeneous way thousands of astronomical catalogues gathered since decades by the Centre de Donnees de Strasbourg (CDS) and participating institutes. The history and current status of this large collection is briefly presented, and the way these catalogues are being standardized to fit in the VizieR system is described. The architecture of the database is then presented, with emphasis on the management of links and of accesses to very large catalogues. Several query interfaces are currently available, making use of the ASU protocol, for browsing purposes or for use by other data processing systems such as visualisation tools.Comment: 10 pages, 2 Postscript figures; to be published in A&A

Estimates of scale and cost efficiency for Federal Reserve currency operations

Meeting the currency demands of depository institutions, businesses, and consumers costs the Federal Reserve more than half a billion dollars each year, yet, very little research has been devoted to understanding what factors affect such costs. The authors estimate a cost function in order to obtain estimates of scale and cost efficiency for this service. They find that as in other paper-based technologies, such as checks, scale economies are achieved at a relatively low level of output, implying that currency services are not a natural monopoly. They also provide estimates of facility-specific marginal costs and returns to scale measures that could be used to improve resource allocations. Lastly, they find that the average processing facility operates at more 80 percent of the efficiency of the “best practice” facility, comparable to cost efficiency estimates that have been reported elsewhere for private-sector financial institutions.Federal Reserve banks - Costs ; Payment systems

Temporal variability in dissolved organic carbon and radiocarbon in the eastern North Pacific Ocean

The factors regulating the steady state inventories and residence times of dissolved organic carbon (DOG) in the deep ocean are not well established. Previous studies of DOC have been limited to single time-point profiles that provide general information on the potential role of vertical advective-diffusive processes in controlling DOC distributions and mean apparent ages. We present results from a 2-year time series station in the eastern North Pacific (station M) where short-term (months) changes in inventories and Delta(14)C signatures of DOC as measured in deep profiles were examined in conjunction with changes in particulate organic carbon (POC) pools. Significant long-term (i.e., months to years) changes in both DOC concentrations and Delta(14)C values were observed. These changes were especially evident at mesopelagic (similar to 450 and 700 m) depths, close to the oxygen minimum. Both within the mixed layer and at mesopelagic depths, positive relationships were found between DOC Delta(14)C values and concentrations of station M, primarily reflecting diminishing vertical inputs of recent DOC throughout the main thermocline. At abyssal depths (greater than or equal to 1600 m), however, Delta(14)C was inversely correlated with DOC concentration. The Delta(14)C signature of the less abundant suspended and sinking POC pools has been observed to fluctuate over seasonal timescales at station M, presumably due:in part to sorption of DOC to POC [Druffel et al., 1996]. However, the Delta(14)C values and concentrations of the correspondingly much larger DOC pool do not appear to be related to seasonal changes in either sinking POC fluxes or suspended POC abundances. Significantly elevated concentrations of DOC were observed at station M when compared with a previously occupied site in the north central Pacific (NCP) in all regions of the water column except mesopelagic depths, where concentrations were lower. The corresponding Delta(14)C values of DOC at all depths at station M were lower than in the NCP. We speculate that dissimilarities in the size and Delta(14)C signature of the DOC pools at seasonally productive station M and the oligotrophic NCP result from differences in DOC sources and sinks between the two regions, as well as from the magnitude of interaction between DOC and POC at these sites

The Albedo Distribution of Near Earth Asteroids

The cryogenic WISE mission in 2010 was extremely sensitive to asteroids and not biased against detecting dark objects. The albedos of 428 Near Earth Asteroids (NEAs) observed by WISE during its fully cryogenic mission can be fit quite well by a 3 parameter function that is the sum of two Rayleigh distributions. The Rayleigh distribution is zero for negative values, and follows $f(x) = x \exp[-x^2/(2\sigma^2)]/\sigma^2$ for positive x. The peak value is at x=\sigma, so the position and width are tied together. The three parameters are the fraction of the objects in the dark population, the position of the dark peak, and the position of the brighter peak. We find that 25.3% of the NEAs observed by WISE are in a very dark population peaking at $p_V = 0.03$, while the other 74.7% of the NEAs seen by WISE are in a moderately dark population peaking at $p_V = 0.168$. A consequence of this bimodal distribution is that the Congressional mandate to find 90% of all NEAs larger than 140 m diameter cannot be satisfied by surveying to H=22 mag, since a 140 m diameter asteroid at the very dark peak has H=23.7 mag, and more than 10% of NEAs are darker than p_V = 0.03.Comment: 7 pages LaTex, 4 figures, accepted for publication in the Astronomical Journa

A Comparison of Scleractinian Coral Abundance Between Natural and Artificial Substrata in a High-Latitude Environment Off Broward County, Florida, USA

The Dania Beach Erojacks Artificial Reef was deployed off the coast of Broward County, Florida on December 31, 1967 as a way to help combat beach erosion. Over the last forty years, the linear pile of concrete hexapods has become an important habitat, for scleractinian corals, octocorals, algae, crustaceans, mollusks, and fish. This study focuses on the density and size of the scleractinian corals found on this artificial reef and how it compares to that of the nearby natural reef. In addition, the impact of two hurricanes on the shallow portion of the artificial reef was documented. In the 2-year study, results indicate that there was higher coral cover on the natural reef (6.45%) compared to 4.27% cover on the artificial reef. Most of the colonies on the natural reef are larger than those found on the artificial reef; 65.6% vs. 29.7% were greater than 25cm2. When comparing colony numbers, there are more than three times as many on the artificial reef (3870) compared to the same area of natural reef (1133). This corresponds to colony densities of 5.0/m2 on the artificial reef, compared to 1.5/m2 on the natural reef. The passage of two hurricanes in close proximity to the artificial reef resulted in no decrease in the number and surface area of corals when pre- and post-hurricane values were compared. Surprisingly, there were significant increases in both coral abundance (GEE Analysis, p \u3c 0.0001) and cover (GEE Analysis, p =0.0001), however these changes were attributed to improved proficiency of the researchers in finding corals rather than actual increases in these values

Course over ground

This exhibition, Course Over Ground, cohesively combines a metaphorical reference to maritime navigation with sculptural forms that convey balance, tension, and control. My mixed media sculptures are conceived with an adherence to the formalist perspective of objects. Each sculpture exists as an honest form. The work, and my intention in making it, is evidence of the process of breaking down selective images or objects into what I understand to be their purest representational forms, such as a squares, cylinders, pyramids, and rectangles. I allude to themes and the metaphor of a journey, which coupled alongside my continual quest for self-discovery, has been manifested into sculptures that aid the viewer as they navigate the gallery space

Temporal variability in dissolved organic carbon and radiocarbon in the eastern North Pacific Ocean

The factors regulating the steady state inventories and residence times of dissolved organic carbon (DOG) in the deep ocean are not well established. Previous studies of DOC have been limited to single time-point profiles that provide general information on the potential role of vertical advective-diffusive processes in controlling DOC distributions and mean apparent ages. We present results from a 2-year time series station in the eastern North Pacific (station M) where short-term (months) changes in inventories and Delta(14)C signatures of DOC as measured in deep profiles were examined in conjunction with changes in particulate organic carbon (POC) pools. Significant long-term (i.e., months to years) changes in both DOC concentrations and Delta(14)C values were observed. These changes were especially evident at mesopelagic (similar to 450 and 700 m) depths, close to the oxygen minimum. Both within the mixed layer and at mesopelagic depths, positive relationships were found between DOC Delta(14)C values and concentrations of station M, primarily reflecting diminishing vertical inputs of recent DOC throughout the main thermocline. At abyssal depths (greater than or equal to 1600 m), however, Delta(14)C was inversely correlated with DOC concentration. The Delta(14)C signature of the less abundant suspended and sinking POC pools has been observed to fluctuate over seasonal timescales at station M, presumably due:in part to sorption of DOC to POC [Druffel et al., 1996]. However, the Delta(14)C values and concentrations of the correspondingly much larger DOC pool do not appear to be related to seasonal changes in either sinking POC fluxes or suspended POC abundances. Significantly elevated concentrations of DOC were observed at station M when compared with a previously occupied site in the north central Pacific (NCP) in all regions of the water column except mesopelagic depths, where concentrations were lower. The corresponding Delta(14)C values of DOC at all depths at station M were lower than in the NCP. We speculate that dissimilarities in the size and Delta(14)C signature of the DOC pools at seasonally productive station M and the oligotrophic NCP result from differences in DOC sources and sinks between the two regions, as well as from the magnitude of interaction between DOC and POC at these sites

Spherical collapse model in agegraphic dark energy cosmologies

Under the commonly used spherical collapse model, we study how dark energy affects the growth of large scale structures of the Universe in the context of agegraphic dark energy models. The dynamics of the spherical collapse of dark matter halos in nonlinear regimes is determined by the properties of the dark energy model. We show that the main parameters of the spherical collapse model are directly affected by the evolution of dark energy in the agegraphic dark energy models. We compute the spherical collapse quantities for different values of agegraphic model parameter $\alpha$ in two different scenarios: first, when dark energy does not exhibit fluctuations on cluster scales, and second, when dark energy inside the overdense region collapses similar to dark matter. Using the Sheth-Tormen and Reed mass functions, we investigate the abundance of dark matter halos in the framework of agegraphic dark energy cosmologies. The model parameter $\alpha$ is a crucial parameter in order to count the abundance of dark matter halos. Specifically, the present analysis suggests that the agegraphic dark energy model with bigger (smaller) value of $\alpha$ predicts less (more) virialized halos with respect to that of $\Lambda$CDM cosmology. We also show that in agegraphic dark energy models, the number of halos strongly depends on clustered or uniformed distributions of dark energy.Comment: 14 pages, 7 figures. Accepted in Physical Review