The blazar 0059+581: Successful prognosis of activity

Our earlier joint analysis of light curves for the blazar 0059+581 at 4.8, 8, 14.5, 22, and 37 GHz with high-resolution VLBI images led us to suggest that the activity in this source develops in cycles, or periods, with a duration of about four years, with a “typical scenario” for the development of the source’s activity taking place over a cycle. Based on this analysis, we predicted in 2002 that a new superluminal component would be ejected from the core of this source in a structural position angle ～170° no later than by the end of 2003. A 43-GHz VLBI image obtained on September 14, 2003, as part of a program to monitor the structure of reference sources used for a radio astronomical coordinate system, convincingly confirms the correctness of this prediction. This is the first time in the history of radio astronomy that a new superluminal component has been detected at a predicted time and in a predicted structural position angle.     

Organic matter diagenesis in shallow water carbonate sediments

Muddy carbonate deposits near the Dry Tortugas, Florida, are characterized by high organic carbon remineralization rates. However, approximately half of the total sedimentary organic matter potentially supporting remineralization is occluded in CaCO₃ minerals (intracrystalline). While a portion of nonintracrystalline organic matter appears to cycle rapidly, intracrystalline organic matter has an approximately constant concentration with depth, suggesting that as long as its protective mineral matrix is intact, it is not readily remineralized. Organic matter in excess of intracrystalline organic matter that is preserved may have a variety of mineral associations (e.g., intercrystalline, adsorbed or detrital). In surface sediment, aspartic acid contributed ∼22 mole % and ∼50 mole % to nonintracrystalline and intracrystalline pools, respectively. In deeper sediment (1.6-1.7m), the composition of hydrolyzable amino acids in both pools was similar (aspartic acid ∼40 mole %). Like amino acids, intracrystalline and nonintracrystalline fatty acids have different compositions in surface sediments, but are indistinguishable at depth. These data suggest that preserved organic matter in the nonintracrystalline pool is stabilized by its interactions with CaCO₃. Neutral lipids are present in very low abundances in the intracrystalline pool and are extensively degraded in both the intracrystalline and nonintracrystalline pools, suggesting that mineral interactions do not protect these compounds from degradation. The presence of chlorophyll-a, but absence of phytol, in the intracrystalline lipid pool demonstrates that chloropigments are present only in the nonintracrystalline pool. Sedimentary chloropigments decrease with depth at similar rates in Dry Tortugas sediments as found in alumino-silicate sediments from the Long Island Sound, suggesting that chloropigment degradation is largely unaffected by mineral interactions. Overall, however, inclusion and protection of organic matter by biominerals is a major pathway for organic matter preservation in this low-organic carbon, biomineral-rich regime.     

An approach to folding kinematics from the analysis of folded oblique surfaces

Two-dimensional analysis of folded surfaces oblique to the mechanical layering can shed light on the kinematic mechanisms that operated during the development of folds. A new version of the program ‘FoldModeler’, developed in the Mathematica™ environment, is used to obtain the deformed configuration of an initial pattern of oblique surfaces deformed by any combination of the most common kinematic folding mechanisms: flexural flow, tangential longitudinal strain, with or without area change and heterogeneous simple shear. The layer can also undergo any form of homogeneous strain at any moment of the folding process. The outputs of the program provide complete information about the strain distribution in the folded layer that includes graphs of the angle between the oblique surfaces as a function of the inclination of the layering through the fold. These graphs can be very useful to discriminate between the mechanisms that operate in the development of natural folds, and they have been obtained and discussed for the most common combinations of strain patterns. The program is applied to obtain theoretical folds that give a good fit of some natural examples of folded oblique surfaces.     

A fluorosensor for two-dimensional measurements of extracellular enzyme activity in marine sediments

A novel planar fluorosensor has been developed for measuring two-dimensional activity distributions of the extracellular enzyme, leucine-aminopetidase (Leu-AP), in marine sediments. The sensor is a foil consisting of an enzyme substrate l-leucine 7-amido-4-methylcoumarin hydrochloride (Leu-MCA) and a Hydromed D4 membrane, backed by a polyester sheet. In its present application, the sensor foil is introduced into surficial deposits to a depth of ~ 10–15 cm, and time dependent fluorescence production occurring in successive digital images is used to resolve enzyme activity patterns. Corrections for microenvironmental variability (e.g., diffusion and adsorption properties) and background reflectance were made. The planar fluorosensor technique was standardized by comparison with traditional slurry based methods using homogenized sediment sections. Spatially averaged, vertical enzyme activity profiles measured using the imaging sensor system were contrasted with the traditional method to verify the reliability of this new approach. The new system resolves enzyme activity on a submillimeter scale over relatively large areas (~ 50–100 cm²). In addition to allowing rapid determination of enzyme activity patterns in undisturbed material, the transparent nature of the sensing foils permits direct correlation of enzyme distributions to heterogeneous biological and physical structure.     

A photometric perturbation of the counterglow

A weakening of the radiance of the counterglow in the anti-solar direction relative to the regions 5°–15° away is interpreted as evidence for a cloud of scattering material in the general region of the Earth-Moon system. Further evidence is indicated, by the relative brightening at ?180° in the vicinity of the L4 libration point, that the cloud is significantly denser there than in adjacent locations.     

A prolonged flare in the blazar 3C 454.3

We present an analysis of data from multi-frequency monitoring of the blazar 3C 454.3 in 2010–2012, when the source experienced an unusually prolonged flare with a duration of about two years. This corresponds to the orbital period of the companion in a scenario in which two supermassive black holes are present in the nucleus of 3C 454.3. The flare’s shape, duration, and amplitude can be explained as a result of precession, if the plane of the accretion disk and the orbital plane of the binary are coincident. We detected small-scale structure of the flare, on time scales of no more than a month. These features probably correspond to inhomogeneities in the accretion disk and surrounding regions, with sizes of the order of 10¹⁵ cm. We estimated the size of the accretion disk based on the dynamical and geometrical parameters of this binary system: its diameter is comparable to the size of the orbit of the supermassive binary black hole, and its thickness does not exceed the gravitational radius of the central black hole. The presence of characteristic small-scale features during the flare makes it possible to estimate the relative time delays of variations in different spectral ranges: from gamma-ray to millimeter wavelengths.     

The solar abundance of thulium

The solar spectrum contains one relatively unblended line λ 3131.258 Tm ii which yields a thulium abundance of log N(Tm)/N(H) + 12 = {Tm} = 0.80 ± 0.10, with the Corliss and Bozman f-value. A recent beam-foil experiment suggests that the thulium abundance may be reduced to {Tm} = 0.30.     

The solar abundance of gold

From 13 scans obtained with a double-band pass spectrograph at the Snow telescope at Mount Wilson, interpreted by the method of spectral synthesis, the abundance of gold turns out to be log [N(Au)/N(H)] + 12 = 0.70, assuming loggf = – 0.57.