The estimation and characterization of plankton populations by pigment analyses. I. The absorption spectra of some pigments occuring in diatoms, dinoflagellates and brown algae

The spectra of chlorophyll c, beta carotene, neofucoxanthin A, neofucoxanthin B, fucoxanthin, diadinoxanthin and diatoxanthin in 90% acetone solutions are reported. These constants are necessary for the simultaneous spectrophotometric determination of the major plankton pigments described

Dissolved silicate and related properties of some western North Atlantic and Carribean Waters

Dissolved silicate, phosphate, nitrate, and oxygen as well as salinity and temperature were observed in several regions around the Antilles Arc and in the Woods Hole-Bermuda area. It is shown that silicate is generally in low concentration in surface waters, where its ratio to phosphate, nitrate and oxygen consumption is variable...

Nutrient regeneration from phytoplankton decomposing in seawater

A laboratory model of the regeneration of the inorganic nutrient salts of phosphorus, nitrogen, and silicon from diatom cells decaying in the dark while subject to bacterial attack was studied. The system was analyzed for phosphate, dissolved and particulate organic phosphorus, ammonia, nitrite, nitrate, dissolved and particulate nitrogen, and orthosilicate concentrations. The observations extended over a period of more than one year, but the significant changes appear to have been restricted to the first five months...

The estimation and characterization of plankton populations by pigment analysis. III. A note on the use of Millipore membrane filters in the estimation of plankton pigments.

Collection of plankton samples on AA (aerosol assay) type Millipore membrane filters has been substituted for centrifugation in the method of Richards with Thompson for estimating plankton pigments. Although the filter dissolves in the 90% acetone that is subsequently used for extracting the pigments, its solution does not interfere with the spectrophotometric determination of the chlorophyll and carotenoid components

The estimation and characterization of plankton populations by pigment analyses II. A spectrophotometric method for the estimation of plankton pigments

A semimicro spectrophotometric method is described for the estimation of chlorophyll a, b, and c and of astacin and nonastacin type carotenoids in acetone extracts of plant and animal material. Developed specifically for use in estimating and characterizing plankton populations, the method is highly sensitive and practical for shipboard use. Methods of collecting, preparing and extracting plankton samples, spectrophotometric measurements, computation of results, and errors are discussed

The Occurrence and Distribution of Methane in the Marine Environment

The distributions of methane dissolved in the sulfide-bearing waters of the Black Sea, the Cariaco Trench, and Lake Nitinat are reported. The gas was not detected in the oxygen-deficient water of the eastern tropical Pacific Ocean, in the Santa Barbara Basin, nor in the sulfide-bearing water of Saanich Inlet. Maximum concentrations observed were 70 μmole CH4/l., and the distribution tends to follow that of sulfide. The data indicate that methane is derived from organic compounds not containing nitrogen or phosphorus and that its formation is much slower than that of sulfide. The solubility coefficient in seawater (salinity = 40‰) is 0.0211. (S.T.P.)/l. at 30°C and increases to 0.041 at 5°C. The processes by which methane may be formed in the marine environment are discussed

The NIR to UV continuum of radio loud vs. radio quiet quasars

Starting from a sample of SDSS quasars appearing also in the 2MASS survey, we study the continuum properties of about 1000 objects observed in 8 bands, from NIR to UV. We construct the mean spectral energy distribution (SED) and compare and contrast the continua of radio loud (RLQ) and radio quiet (RQQ) objects. The SEDs of the two populations are significantly different in the sense that RLQs are redder, with power law spectral indices =-0.55+/-0.04 and =-0.31+/-0.01 in the spectral range between 10^14.5 and 10^15.35 Hz. This difference is discussed in terms of different extinctions, different disc temperatures, or slopes of the non-thermal component.Comment: 7 pages, 6 figures. To appear in MNRA

Photometric redshifts and quasar probabilities from a single, data-driven generative model

We describe a technique for simultaneously classifying and estimating the redshift of quasars. It can separate quasars from stars in arbitrary redshift ranges, estimate full posterior distribution functions for the redshift, and naturally incorporate flux uncertainties, missing data, and multi-wavelength photometry. We build models of quasars in flux-redshift space by applying the extreme deconvolution technique to estimate the underlying density. By integrating this density over redshift one can obtain quasar flux-densities in different redshift ranges. This approach allows for efficient, consistent, and fast classification and photometric redshift estimation. This is achieved by combining the speed obtained by choosing simple analytical forms as the basis of our density model with the flexibility of non-parametric models through the use of many simple components with many parameters. We show that this technique is competitive with the best photometric quasar classification techniques---which are limited to fixed, broad redshift ranges and high signal-to-noise ratio data---and with the best photometric redshift techniques when applied to broadband optical data. We demonstrate that the inclusion of UV and NIR data significantly improves photometric quasar--star separation and essentially resolves all of the redshift degeneracies for quasars inherent to the ugriz filter system, even when included data have a low signal-to-noise ratio. For quasars spectroscopically confirmed by the SDSS 84 and 97 percent of the objects with GALEX UV and UKIDSS NIR data have photometric redshifts within 0.1 and 0.3, respectively, of the spectroscopic redshift; this amounts to about a factor of three improvement over ugriz-only photometric redshifts. Our code to calculate quasar probabilities and redshift probability distributions is publicly available

Metal-carbohydrates

Title from folder label.Project report form no. 1 dated September 9, 1966. Structure studies of metal-carbohydrate complexes / Mark A. Lamka -- Project report form no. 2 dated September 3, 1968. Structure studies of metal-carbohydrate complexes / Gerald F. Richards

Eml1 loss impairs apical progenitor spindle length and soma shape in the developing cerebral cortex

The ventricular zone (VZ) of the developing cerebral cortex is a pseudostratified epithelium that contains progenitors undergoing precisely regulated divisions at its most apical side, the ventricular lining (VL). Mitotic perturbations can contribute to pathological mechanisms leading to cortical malformations. The HeCo mutant mouse exhibits subcortical band heterotopia (SBH), likely to be initiated by progenitor delamination from the VZ early during corticogenesis. The causes for this are however, currently unknown. Eml1, a microtubule (MT)-associated protein of the EMAP family, is impaired in these mice. We first show that MT dynamics are perturbed in mutant progenitor cells in vitro. These may influence interphase and mitotic MT mechanisms and indeed, centrosome and primary cilia were altered and spindles were found to be abnormally long in HeCo progenitors. Consistently, MT and spindle length regulators were identified in EML1 pulldowns from embryonic brain extracts. Finally, we found that mitotic cell shape is also abnormal in the mutant VZ. These previously unidentified VZ characteristics suggest altered cell constraints which may contribute to cell delamination