Cleaning the USNO-B Catalog through automatic detection of optical artifacts

The USNO-B Catalog contains spurious entries that are caused by diffraction spikes and circular reflection halos around bright stars in the original imaging data. These spurious entries appear in the Catalog as if they were real stars; they are confusing for some scientific tasks. The spurious entries can be identified by simple computer vision techniques because they produce repeatable patterns on the sky. Some techniques employed here are variants of the Hough transform, one of which is sensitive to (two-dimensional) overdensities of faint stars in thin right-angle cross patterns centered on bright (<13 \mag) stars, and one of which is sensitive to thin annular overdensities centered on very bright (<7 \mag) stars. After enforcing conservative statistical requirements on spurious-entry identifications, we find that of the 1,042,618,261 entries in the USNO-B Catalog, 24,148,382 of them (2.3 \percent) are identified as spurious by diffraction-spike criteria and 196,133 (0.02 \percent) are identified as spurious by reflection-halo criteria. The spurious entries are often detected in more than 2 bands and are not overwhelmingly outliers in any photometric properties; they therefore cannot be rejected easily on other grounds, i.e., without the use of computer vision techniques. We demonstrate our method, and return to the community in electronic form a table of spurious entries in the Catalog.Comment: published in A

Specific Chemical Interaction Affecting the Stability of Dispersed Systems

1) Sorbable species may destabilize colloids at much lower concentrations than nonsorbable ions. The VODL double layer model neglects the dominating role that chemical forces play in causing adsorption and is restricted in its application to lyophilic colloids and simple electrolytes. 2) The distribution of ions in an oxide-electrolyte interface can be evaluated from alkalimetric and acidimetric titration curves of aqueous dispersions of these oxides. 3) A comparison of the differential capacity of the interface at an oxide-electrolyte interface with that of Hg or Ag! shows much larger capacitance values for the hydrophilic strongly aquated oxide surface than for the more hydrophobic surface of Hg and Ag!. The difference is caused primarily by the strongly structured, extensively hydrogen-bonded and chemisorbed water layer immediately adjacent to the solid oxide surface. Ions tend strongly to penetrate (specific sorption) into the compact part of the double layer adjoining the oxide surface, and may thus exert a marked effect on the surface chemical properties beyond those observed by a mere compaction of the diffuse part of the double layer. 4) Association of oxide surfaces with H+, and other cations can, similar as with polyelectrolytes, be characterized by acidity and stability constants. The latter constants can be expressed as intrinsic constants if they are corrected to a hypothetically chargeless surface. The specificity of the interaction with H+ and cations can be understood by considering simple electrostatic models. This association of oxide surfaces with cations can be used to explain the effect of cations such as Ca2+ on the stability of hydrous oxide colloids, and on the deposition of Mn02 particles on sand surfa ces. The extent to which a coagulant species is specifically adsorbed is reflected in the c. c. c. necessary to produce a ggregation. When the specifically adsorbed species and the colloid are of opposite charge, the sorbed species act to reduce the surface charge of the colloid. The destabilizing agent can, in some cases, even reverse the colloid charge and restabilization will occur. 5) Specific cation interactions as described here represent a basis of related ion specific processes, such as the behavior of ion selective glass or membrane electrodes; the selective ion permeability of cell membranes and potential generating mechanisms in the living cell

Heterocyst placement strategies to maximize growth of cyanobacterial filaments

Under conditions of limited fixed-nitrogen, some filamentous cyanobacteria develop a regular pattern of heterocyst cells that fix nitrogen for the remaining vegetative cells. We examine three different heterocyst placement strategies by quantitatively modelling filament growth while varying both external fixed-nitrogen and leakage from the filament. We find that there is an optimum heterocyst frequency which maximizes the growth rate of the filament; the optimum frequency decreases as the external fixed-nitrogen concentration increases but increases as the leakage increases. In the presence of leakage, filaments implementing a local heterocyst placement strategy grow significantly faster than filaments implementing random heterocyst placement strategies. With no extracellular fixed-nitrogen, consistent with recent experimental studies of Anabaena sp. PCC 7120, the modelled heterocyst spacing distribution using our local heterocyst placement strategy is qualitatively similar to experimentally observed patterns. As external fixed-nitrogen is increased, the spacing distribution for our local placement strategy retains the same shape while the average spacing between heterocysts continuously increases.Comment: This is an author-created, un-copyedited version of an article accepted for publication in Physical Biology. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from it. The definitive publisher-authenticated version will be available onlin

Intelligence,Childhood Behaviour, and Locus of Control: Effects on Intergenerational Social Mobiliy.

In a sample of 3,788 men from the British Cohort Study 1970, predictors of intergenerational social mobility were examined. Logistic regression models confirmed previous research outcomes: parental social class, intelligence, and educational qualifications significantly contributed to status attainment at the age of 30. In addition, childhood behavioural disturbance, extracted from teacher ratings at children’s age of 10, and locus of control were identified as influential factors. Subsequently, a structural equation model was fitted, which extends pervious findings. Locus of control and behavioural disturbance mediated effects of intelligence on education and status attainment. However, both predictors were less affected by parental social class. Overall, educational qualifications were most predictive of social mobility, mediating effects of parental social class, intelligence, locus of control and childhood behaviour on own social class at age 30

Citations and References in the Journal of Paleontology

666-672http://deepblue.lib.umich.edu/bitstream/2027.42/48563/2/ID420.pd

Check List of Fossil Invertebrates Described from the Middle Devonian Silica Formation of Northwestern Ohio and Southeastern Michigan

123-137http://deepblue.lib.umich.edu/bitstream/2027.42/48412/2/ID259.pd

Phyllocarid Crustaceans from the Middle Devonian Silica Shale of Northwestern Ohio and Southeastern Michigan

53-71http://deepblue.lib.umich.edu/bitstream/2027.42/48445/2/ID294.pd

An abyssal hill fractionates organic and inorganic matter in deep-sea surface sediments

Current estimates suggest that more than 60% of the global seafloor are covered by millions of abyssal hills and mountains. These features introduce spatial fluid-dynamic granularity whose influence on deep-ocean sediment biogeochemistry is unknown. Here we compare biogeochemical surface-sediment properties from a fluid-dynamically well-characterized abyssal hill and upstream plain: (1) In hill sediments, organic-carbon and -nitrogen contents are only about half as high as on the plain while proteinaceous material displays less degradation; (2) on the hill, more coarse-grained sediments (reducing particle surface area) and very variable calcite contents (influencing particle surface charge) are proposed to reduce the extent, and influence compound-specificity, of sorptive organic-matter preservation. Further studies are needed to estimate the representativeness of the results in a global context. Given millions of abyssal hills and mountains, their integrative influence on formation and composition of deep-sea sediments warrants more attention

Weight‐of‐Evidence Approach for Assessing Removal of Metals from the Water Column for Chronic Environmental Hazard Classification

The United Nations and the European Union have developed guidelines for the assessment of long‐term (chronic) chemical environmental hazards. This approach recognizes that these hazards are often related to spillage of chemicals into freshwater environments. The goal of the present study was to examine the concept of metal ion removal from the water column in the context of hazard assessment and classification. We propose a weight‐of‐evidence approach that assesses several aspects of metals including the intrinsic properties of metals, the rate at which metals bind to particles in the water column and settle, the transformation of metals to nonavailable and nontoxic forms, and the potential for remobilization of metals from sediment. We developed a test method to quantify metal removal in aqueous systems: the extended transformation/dissolution protocol (T/DP‐E). The method is based on that of the Organisation for Economic Co‐operation and Development (OECD). The key element of the protocol extension is the addition of substrate particles (as found in nature), allowing the removal processes to occur. The present study focused on extending this test to support the assessment of metal removal from aqueous systems, equivalent to the concept of “degradability” for organic chemicals. Although the technical aspects of our proposed method are different from the OECD method for organics, its use for hazard classification is equivalent. Models were developed providing mechanistic insight into processes occurring during the T/DP‐E method. Some metals, such as copper, rapidly decreased (within 96 h) under the 70% threshold criterion, whereas others, such as strontium, did not. A variety of method variables were evaluated and optimized to allow for a reproducible, realistic hazard classification method that mimics reasonable worst‐case scenarios. We propose that this method be standardized for OECD hazard classification via round robin (ring) testing to ascertain its intra‐ and interlaboratory variability. Environ Toxicol Chem 2019;38:1839–1849. © 2019 SETAC.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/151334/1/etc4470_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/151334/2/etc4470.pd

Specific Chemical Interaction Affecting the Stability of Dispersed Systems

1) Sorbable species may destabilize colloids at much lower concentrations than nonsorbable ions. The VODL double layer model neglects the dominating role that chemical forces play in causing adsorption and is restricted in its application to lyophilic colloids and simple electrolytes. 2) The distribution of ions in an oxide-electrolyte interface can be evaluated from alkalimetric and acidimetric titration curves of aqueous dispersions of these oxides. 3) A comparison of the differential capacity of the interface at an oxide-electrolyte interface with that of Hg or Ag! shows much larger capacitance values for the hydrophilic strongly aquated oxide surface than for the more hydrophobic surface of Hg and Ag!. The difference is caused primarily by the strongly structured, extensively hydrogen-bonded and chemisorbed water layer immediately adjacent to the solid oxide surface. Ions tend strongly to penetrate (specific sorption) into the compact part of the double layer adjoining the oxide surface, and may thus exert a marked effect on the surface chemical properties beyond those observed by a mere compaction of the diffuse part of the double layer. 4) Association of oxide surfaces with H+, and other cations can, similar as with polyelectrolytes, be characterized by acidity and stability constants. The latter constants can be expressed as intrinsic constants if they are corrected to a hypothetically chargeless surface. The specificity of the interaction with H+ and cations can be understood by considering simple electrostatic models. This association of oxide surfaces with cations can be used to explain the effect of cations such as Ca2+ on the stability of hydrous oxide colloids, and on the deposition of Mn02 particles on sand surfa ces. The extent to which a coagulant species is specifically adsorbed is reflected in the c. c. c. necessary to produce a ggregation. When the specifically adsorbed species and the colloid are of opposite charge, the sorbed species act to reduce the surface charge of the colloid. The destabilizing agent can, in some cases, even reverse the colloid charge and restabilization will occur. 5) Specific cation interactions as described here represent a basis of related ion specific processes, such as the behavior of ion selective glass or membrane electrodes; the selective ion permeability of cell membranes and potential generating mechanisms in the living cell