Nimbus Telemetry

Nimbus satellite - pulse-code-modulated telemetry subsyte

Deep Space Network utilization for flight projects, calendar year 1981

A report on the utilization of the Deep Space Network during calendar year 1981 in support of all flight projects is presented. The network expended 63% of its total capability in support of Space Flight projects

Compound-Specific δ^(34)S Analysis of Volatile Organics by Coupled GC/Multicollector-ICPMS

We have developed a highly sensitive and robust method for the analysis of δ^(34)S in individual organic compounds by coupled gas chromatography (GC) and multicollector inductively coupled plasma mass spectrometry (MC-ICPMS). The system requires minimal alteration of commercial hardware and is amenable to virtually all sample introduction methods. Isobaric interference from O_2^+ is minimized by employing dry plasma conditions and is cleanly resolved at all masses using medium resolution on the Thermo Neptune MC-ICPMS. Correction for mass bias is accomplished using standard−sample bracketing with peaks of SF6 reference gas. The precision of measured δ^(34)S values approaches 0.1‰ for analytes containing >40 pmol S and is better than 0.5‰ for those containing as little as 6 pmol S. This is within a factor of 2 of theoretical shot-noise limits. External accuracy is better than 0.3‰. Integrating only the center of chromatographic peaks, rather than the entire peak, offers significant gain in precision and chromatographic resolution with minimal effect on accuracy but requires further study for verification as a routine method. Coelution of organic compounds that do not contain S can cause degraded analytical precision. Analyses of crude oil samples show wide variability in δ^(34)S and demonstrate the robustness and precision of the method in complex environmental samples

Identification and Characterization of Novel Sir3/MeCP2-Chromatin Interactions

The eukaryotic genome is packaged into chromosomes that are made up of a highly organized and heavily regulated structure called chromatin. The proteins involved in the compaction of DNA into this condensed state are mostly understood at the level of the structure of the nucleosome. The higher order arrangement of chromatin and how it effects gene regulation is only partially understood and characterized. The compaction of nucleosomal arrays into 30-nm and higher structures are partially the responsibility of architectural, or structural, chromatin associated proteins. The following dissertation analyzes the individual chromatin contributions of two well studied architectural proteins, the yeast silencing protein Silent Information Regulator 3 (Sir3) and the human transcriptional regulator methyl CpG binding protein 2 (MeCP2). Silencing in yeast is the responsibility of the SIR family of proteins. Classically, the Sir3 protein has been characterized as associating with chromatin through the hypo-acetylated N-termini of the core histones H3 and H4. The Sir3 protein has recently been found to contain a DNA-binding element, my studies characterized Sir3-nucleic acid interactions and showed that Sir3 can bind to chromatin independently of histone N-termini. In contrast, the MeCP2 protein has classically been characterized as a methylated DNA dependent transcriptional repressor, but recent genome-wide analysis reveals MeCP2 distribution can occur on promoters of active genes. Recent in vitro work with MeCP2 and nucleosomal arrays showed a highly ordered, compacted chromatin structure even in the absence of DNA methylation. MeCP2 is of particular biological interest due to the observed link with the neurodevelopmental iii disorder Rett Syndrome (RTT). My studies demonstrated that MeCP2 can bind in vitro to the Ntermini of core histones H2A, H3, and H4. Additionally, the removal of these tails impacted MeCP2-chromatin interactions, and resulted in a reduced level of nucleosomal array condensation. Importantly, the two RTT mutants analyzed here, R133C and R168X, exhibited differential binding to histone N-termini. These results add to the understanding of chromatin organization and arrangement by demonstrating and characterizing additional chromatin contacts for these two chromatin associated proteins

Using a marginal criteria to determine optimal fungus-free fescue establishment

A marginal revenue criteria was used to determine what reduction in average daily gains from fescue toxicity could be tolerated before it was economically profitable to establish endophyte-free fescue pastures. The current expected net revenue from infected pastures was compared with average net revenue generated from the establishment of endophyte-free pastures. Using the marginal criterion, when net returns from the current infected pasture operation are equal to or less than the average annual returns anticipated from establishing a fungus-free pasture, fescue renewal is profitable. A 10 to 15 percent reduction in average daily gain was required under the assumed conditions before pasture renewal was undertaken. When uncertainty of the stand life was incorporated into the analysis, a further 4 percent reduction in average daily gain was required before establishment was profitable. When no value or decreased value was assumed for crops from the establishment of fungus-free pastures, a fvu-tber reduction in average daily gain was tolerable. The discount rate and planning horizon also influenced the timing of pasture renewal

THE SURVIVAL OF Salmonella typhimurium IN WHOLE CHICKENS COOKED IN SLOW COOKER

Fresh whole roasting chickens were inoculated with a culture containing 2 .5 x 105 Salmonella typhimurium. Water or tomato sauce was added, and the chickens were cooked for six hours at the low temperature setting of the slow cooker . The pH of the sauce or broth was determined before and after cooking. At the end of the cooking period , samples were taken to determine whether any organisms survived the cooking process . The slow cooker was effective in destroying the Salmonella typhimurium on the chickens . None were detected at the end of the cooking period . Tests to determine the survival time of the organism on the chickens showed that the Salmonellae were destroyed at ·a lower temperature in the chickens wit h tomato sauce than in the chickens cooked with water. The low pH of the tomato sauce apparently aided in destruct ion of the organism

The Assessment of Predictor Variables for Hard Tick Abundance in Southwestern Missouri

The risk of tick-borne infection is increasing across the United States, and in Missouri, ticks are expanding into novel regions due to climate change, habitat fragmentation, and biodiversity loss. Regions in which ticks are encroaching experience novel vectors for lineage associated pathogens. Novel tick detection can be low due to sampling practices targeting known ticks, which can lead to unreliable distribution maps and poor predictive distribution models. Such models should account for biotic factors, abiotic factors, and their interactions to provide a dynamic view of their impact on tick abundance and identify variables that can serve as indicators. Further, a simple comparison of sampling methods in different habitats for tick abundance, diversity, and life stage allows for the determination of the most effective sampling technique to gain a holistic view of tick communities. I completed a set of surveys to account for biotic factors, abiotic factors, and sampling design in tick distribution in Southwest Missouri. I used tick drags and sampled the following biotic and abiotic factors: small mammals, ants, ambient temperature, relative humidity, litter depth, and canopy cover. Factors were tested directly on tick abundance using generalized linear models, and indirect relationships, like the effect of location, were analyzed using a linear mixed effect model. To test method efficiency, I executed drags and carbon-dioxide traps in two different habitat types, forest and grassland, and compared captures in terms of abundance, species, and life stages. Indirect relationships and location explained tick abundance more clearly than direct relationship and two methods of sampling resulted in more effective analysis of tick communities. Understanding tick communities and the driving forces behind the movement of tick populations is needed to increase the awareness of public health programs of tick-borne diseases in the region

Thermodynamic constraints on fluctuation phenomena

The relationships between reversible Carnot cycles, the absence of perpetual motion machines and the existence of a non-decreasing, globally unique entropy function forms the starting point of many textbook presentations of the foundations of thermodynamics. However, the thermal fluctuation phenomena associated with statistical mechanics has been argued to restrict the domain of validity of this basis of the second law of thermodynamics. Here we demonstrate that fluctuation phenomena can be incorporated into the traditional presentation, extending, rather than restricting, the domain of validity of the phenomenologically motivated second law. Consistency conditions lead to constraints upon the possible spectrum of thermal fluctuations. In a special case this uniquely selects the Gibbs canonical distribution and more generally incorporates the Tsallis distributions. No particular model of microscopic dynamics need be assumed.Comment: 12 pages, 24 figure