Noise Correlation in Cosmic Microwave Background Experiments

Many analyses of microwave background experiments neglect the correlation of noise in different frequency or polarization channels. We show that these correlations, should they be present, can lead to severe misinterpretation of an experiment. In particular, correlated noise arising from either electronics or atmosphere may mimic a cosmic signal. We quantify how the likelihood function for a given experiment varies with noise correlation, using both simple analytic models and actual data. For a typical microwave background anisotropy experiment, noise correlations at the level of 1\% of the overall noise can seriously {\it reduce} the significance of a given detection.Comment: Analysis generalized; conclusions unaltere

Computer code for single-point thermodynamic analysis of hydrogen/oxygen expander-cycle rocket engines

This analysis and this computer code apply to full, split, and dual expander cycles. Heat regeneration from the turbine exhaust to the pump exhaust is allowed. The combustion process is modeled as one of chemical equilibrium in an infinite-area or a finite-area combustor. Gas composition in the nozzle may be either equilibrium or frozen during expansion. This report, which serves as a users guide for the computer code, describes the system, the analysis methodology, and the program input and output. Sample calculations are included to show effects of key variables such as nozzle area ratio and oxidizer-to-fuel mass ratio

Cochise: A Re-Imagination

This is a fictionalized work that looks at Cochise’s life, through a series of imagined scenarios. My intention in writing this was to provide an intimate venue by which he not only comes alive as an extraordinary warrior and sage archetype, but as a human being who struggled with doubt, loss, and fear. Leadership, honesty, and honor are important themes that Cochise’s life exemplified. Though soft spoken, he imparted volumes on leadership to his people and enemies through his spiritual, emotional, and physical presence.https://scholar.dominican.edu/books/1185/thumbnail.jp

Using a multifrontal sparse solver in a high performance, finite element code

We consider the performance of the finite element method on a vector supercomputer. The computationally intensive parts of the finite element method are typically the individual element forms and the solution of the global stiffness matrix both of which are vectorized in high performance codes. To further increase throughput, new algorithms are needed. We compare a multifrontal sparse solver to a traditional skyline solver in a finite element code on a vector supercomputer. The multifrontal solver uses the Multiple-Minimum Degree reordering heuristic to reduce the number of operations required to factor a sparse matrix and full matrix computational kernels (e.g., BLAS3) to enhance vector performance. The net result in an order-of-magnitude reduction in run time for a finite element application on one processor of a Cray X-MP

Speaker rate detection for voice mail applications

Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1997.Includes bibliographical references (p. 41).by Scott A. Lehman.M.Eng

Plant species effects on soil organic matter turnover and nutrient release in forests and grasslands

1996 Fall.Includes bibliographic references (pages 23-27).Although feedbacks between plant species and ecosystem dynamics have been demonstrated in a variety of terrestrial ecosystems, little research has examined the mechanistic relationship between plant species characteristics, the formation and turnover of soil carbon and nitrogen pools, and ecosystem processes such as net N mineralization. My objective was to examine two possible effects of species on soil C and N dynamics; changes in organic matter quality and changes in soil aggregation. For several forest ecosystems, litter lignin:N ratio correlated negatively (non-linear) with net N mineralization, but the relationship did not apply to grass species. Climatic factors (temperature, precipitation) explained little of the variation in net N mineralization. The relationship between litter lignin:N ratio and net N mineralization from mineral soil and the forest floor was similar, suggesting that plant litter quality affects both forest floor and mineral soil organic matter quality. For tree species monocultures in Wisconsin, net N mineralization during 387 day laboratory incubations indicated that species alter the quality of readily decomposable pools of soil N, and have little effect on more recalcitrant soil N. Changes in the quality of soil N correlated positively with in situ net N mineralization. Grass species did not influence N mineralization. Neither grass nor tree species influenced soil C dynamics, but differences in soil characteristics between sites influenced soil C dynamics. Soil microbes appear to act as a “decay filter”, converting heterogeneous plant material into relatively homogeneous soil humus. Changes in soil aggregate size distribution should alter whole-soil C and N quality because different size aggregates contain organic matter of different quality. Although tree species slightly altered aggregate size distribution, aggregate size distribution related poorly to whole-soil C and net N mineralization. Tree species had no effect on the physical protection of organic matter in soil aggregates or on organic matter quality of different size aggregates. Species characteristics had little effect on soil C mineralization, but species-related changes in the quality of readily decomposable soil N pools (not the pool size) influenced net N mineralization. This suggests that the feedbacks between plant species and soil N cycling occur rapidly, ensuring an adequate nutrient supply when plant community structure changes

The use of an enzyme immunoassay for the detection of salmonellae in foods

An enzyme immunoassay (EIA) was developed to detect Salmonella in foods. The following variables were examined: appropriate enzyme-antibody conjugates, the use of modified commercial antisera, and optimum test protocols to insure specificity and sensitivity. Alkaline phosphatase was the best enzyme probe; cellular peroxidases interfered when peroxidase conjugates were used. Commercial Spicer-Edwards polyvalent H antiserum was a satisfactory source of specific IgG after purification by staphylococcal protein A affinity chromatography to remove IgM. Purification of commercial antisera was necessary because IgM is the primary immunoglobulin class elicited by cross-reactive 0 antigens. An indirect test protocol was developed for use with microtitration plates or Gilford microcuvettes. Samples from enrichment cultures were mixed with H-specific IgG and allowed to react; unbound antibody was then removed by three 5-min centrifugation washes. Goat anti-rabbit alkaline phosphatase antibody conjugate was added and allowed to react; unbound conjugate was removed by centrifugation washing as before. Positive samples were indicated by the production of a chromogenic reaction product following the addition of alkaline phosphatase substrate. The color could be read visually or quantified by using an absorbance colorimeter. Ninety-eight food samples were examined to compare the new EIA procedure with three other salmonellae screening methods, i.e., enrichment serology, immunofluorescence, and the FDA standard pure culture technique. The EIA was sensitive and specific and possessed certain advantages over other methods currently in use. These included the ability to quantify data, simultaneous multisample analysis, and the requirement of little technical expertise to perform the assay. Furthermore, when the EIA was applied to the screening of pre-enrichment media, the results indicated that it might be decidedly more sensitive than the standard pure culture analysis. The feasibility of using the EIA to screen pre-enrichment media and hence, negating the requirement of selective enrichment, shows great potential and warrants further investigation