Formation of ions and radicals from icy grains in comets

Ion and radical formation in comets are thought to occur primarily by photodissociation of gas phase molecules. Experimental evidence and theoretical calculations are presented that show that some of the radical and ions can come directly from ice grains. The experimental evidence suggest that if the frozen molecules on the surface of grains undergo direct dissociation then they may be able to release radicals directly in the gas phase. If the molecules undergo predissociation it is unlikely that they will release radicals in the gas phase since they should be quenched. Calculations of this direct photodissociation mechanism further indicate that even if the parent molecule undergoes direct dissociation, the yield will not be high enough to explain the rays structure in comets unless the radicals are stored in the grains and then released when the grain evaporates. Calculations were also performed to determine the maximum number of ions that can be stored in an icy grain's radius. This number is compared with the ratio of the ion to neutral molecular density. The comparison suggests that some of the ions observed near the nucleus of the comet could have originally been present in the cometary nucleus. It is also pointed out that the presence of these ions in icy grains could lead to radical formation via electron recombination. Finally, an avalanche process was evaluated as another means of producing ions in comets

A practical program to kill Jim Crow

https://stars.library.ucf.edu/prism/1502/thumbnail.jp

Jackson, Charles

Co. L., 371st Medical Battalion; Fort Huachuca, Arizonahttps://dh.howard.edu/prom_members/1047/thumbnail.jp

Computational Methods for Parameter Estimation in Climate Models

Intensive computational methods have been used by Earth scientists in a wide range of problems in data inversion and uncertainty quantification such as earthquake epicenter location and climate projections. To quantify the uncertainties resulting from a range of plausible model configurations it is necessary to estimate a multidimensional probability distribution. The computational cost of estimating these distributions for geoscience applications is impractical using traditional methods such as Metropolis/Gibbs algorithms as simulation costs limit the number of experiments that can be obtained reasonably. Several alternate sampling strategies have been proposed that could improve on the sampling efficiency including Multiple Very Fast Simulated Annealing (MVFSA) and Adaptive Metropolis algorithms. The performance of these proposed sampling strategies are evaluated with a surrogate climate model that is able to approximate the noise and response behavior of a realistic atmospheric general circulation model (AGCM). The surrogate model is fast enough that its evaluation can be embedded in these Monte Carlo algorithms. We show that adaptive methods can be superior to MVFSA to approximate the known posterior distribution with fewer forward evaluations. However the adaptive methods can also be limited by inadequate sample mixing. The Single Component and Delayed Rejection Adaptive Metropolis algorithms were found to resolve these limitations, although challenges remain to approximating multi-modal distributions. The results show that these advanced methods of statistical inference can provide practical solutions to the climate model calibration problem and challenges in quantifying climate projection uncertainties. The computational methods would also be useful to problems outside climate prediction, particularly those where sampling is limited by availability of computational resources.National Science Foundation OCE-0415251CONACyT-Mexico 159764Institute for Geophysic

A study of the iodine content of Missouri vegetables and soils

Investigations have shown that the iodine content of vegetables, water, and soils has a direct relationship to the goiter incidence of a given region. A few countries, notably New Zealand and Switzerland have made a rather complete survey. In the United States, South Carolina has made the most progress in this direction. At the present time there are no available records of vegetable and soil analysis for iodine in Missouri. Hunze determined the amount of iodine in waters in Missouri. The connection of his results with the author\u27s results will be seen later. The present investigation was carried out at the Missouri School of Mines in cooperation with the Missouri State Board of Health --Introduction, page 1

THE ECOLOGICAL CAUSES AND CONSEQUENCES OF PREY CHOICE AND ONTOGENETIC NICHE SHIFTS IN THE COMMON GOBY

Foraging behaviour of the common goby, Pomatoschistus microps was investigated in both the United Kingdom and Sweden, with the aim of establishing causes and consequences of prey choice and ontogenetic shifts in diet. Goby life-cycle could be clearly divided into two stages, where prey choice changed abruptly from meio- to macrofauna at a standard length of 30 mm. This diet-shift maximised net energy intake rates, as illustrated by a quantitatively validated optimal foraging model. Intrinsic mechanisms were of greater importance than extrinsic factors in driving this shift. Metabolism, the primary prey choice determinant, revealed canalised and predictable diet shifts in the face of variable prey availability. This was in strong contrast to the more usual determinants such as gape limitation or extrinsic factors, such as habitat shift, prey availability and predation risk. Post diet-shift gobies consumed a range of benthic macrofauna dependent on availability. This plasticity in prey choice suggested that foraging efficiency was at some level below that expected for specialist foragers. Translocation experiments provided support for the general assertion that learning and experience are mechanisms through which generalist foragers could improve their foraging efficiency. Ontogenetic changes in prey choice did not result in a trade-off between foraging efficiency and other ecological parameters, leading to a prediction, upheld by geometric morphometries, that there would be no change in morphology associated with this change in diet. Conditions precluding diet shifts, and the resulting consequences, were explored using mesocosm manipulations. Adult gobies prevented from feeding on macrofauna suffered reduced condition and fitness. Pomatoschistus microps is an ideal species for investigations into foraging behaviour and has provided valuable support for current foraging paradigms as well as novel insights into the causes and consequences of prey choice

Faith of Our Fathers: A Study of the Nicene Creed

It\u27s not whether you have a creed or not, just which. No creed but Christ. This claim tries to remove the mess of doctrinal controversy. After all, doesn\u27t everyone know that doctrine divides ? But would avoiding creeds and confessions really clear away confusion? What do you believe about Jesus? Was he really God? The answers to these important questions make a creed, even if it\u27s poorly worded or false. Creeds are unavoidable. As the church\u27s first official ecumenical creed, the Nicene Creed has protected and shaped the life of God\u27s people for centuries. L. Charles Jackson\u27s popular study walks readers through every line of the creed, highlighting its history and contemporary application, and revealing its grounding in Scripture. It shows us a Nicene Creed that is pastoral, practical, and personal.https://digitalcommons.cedarville.edu/alum_books/1384/thumbnail.jp