GPS Attitude Determination Using Deployable-Mounted Antennas

The primary objective of this investigation is to develop a method to solve for spacecraft attitude in the presence of potential incomplete antenna deployment. Most research on the use of the Global Positioning System (GPS) in attitude determination has assumed that the antenna baselines are known to less than 5 centimeters, or one quarter of the GPS signal wavelength. However, if the GPS antennas are mounted on a deployable fixture such as a solar panel, the actual antenna positions will not necessarily be within 5 cm of nominal. Incomplete antenna deployment could cause the baselines to be grossly in error, perhaps by as much as a meter. Overcoming this large uncertainty in order to accurately determine attitude is the focus of this study. To this end, a two-step solution method is proposed. The first step uses a least-squares estimate of the baselines to geometrically calculate the deployment angle errors of the solar panels. For the spacecraft under investigation, the first step determines the baselines to 3-4 cm with 4-8 minutes of data. A Kalman filter is then used to complete the attitude determination process, resulting in typical attitude errors of 0.50

Topological Data Analysis for Object Data

Statistical analysis on object data presents many challenges. Basic summaries such as means and variances are difficult to compute. We apply ideas from topology to study object data. We present a framework for using persistence landscapes to vectorize object data and perform statistical analysis. We apply to this pipeline to some biological images that were previously shown to be challenging to study using shape theory. Surprisingly, the most persistent features are shown to be "topological noise" and the statistical analysis depends on the less persistent features which we refer to as the "geometric signal". We also describe the first steps to a new approach to using topology for object data analysis, which applies topology to distributions on object spaces.Comment: 16 pages, 12 figure

Sthreepura cave at Kiriwanagama, south central Sri Lanka: A network cave in saprolite and proterozoic quartzite

Sthreepura Cave at Kiriwanagama consists of an upper level of cavities in quartzite formed by arenization and a lower level developed in a saprolite formed from the weathering of gneiss sandwiched between two layers of quartzite. The lower level cave is not like most arenization and phantom rock caves as the walls are composed of saprolite, not exhumed unweathered rock. The cave is not a soil pipe as it is not in soil, lacks the characteristic features of soil pipes and has formed directly below, not above an aquiclude. Sthreepura Cave at Kiriwanagama is a network cave in saprolite. Speleogenesis in the lower level began with the development of joint-guided tubes in the saprolite directly below the upper layer of quartzite, probably under phreatic conditions. Later erosion under vadose conditions removed the saprolite to produce a network of passages with a rectangular profile. Widening of the passages ultimately caused ceiling failure producing breakdown chambers, but fallen slabs of quartzite armoured the walls of the Main Passage of the cave protecting them from undercutting.Key words: Sri Lanka, gneiss, network cave, saprolite, arenization.Jama Sthreepura pri Kiriwanagami, južni del osrednje Šri Lanke: Mreža rovov v saprolitu in proterozojskem kvarcituJamo St hreepura pri Kiriwanagami sestavljata gornji nivo arenizacijskih votlin v kvarcitu ter spodnji nivo v saprolitu, ki je nastal s preperevanjem gnajsa med plastmi kvarcita. Tudi stene rovov spodnjega nivoja so iz saprolita, kar kaže na drugačen razvoj od znanih arenizacijskih in fantomskih jam. Jama nima lastnosti preperinskih cevi in je v nasprotju s temi nastala neposredno pod (in ne nad) akvikludom. Jama Sthreepura pri Kiriwanagami predstavlja mrežo kanalov nastalih v saprofitu.. Speleogeneza se je začela z razvojem cevi vzdolž razpok v saprolitu, neposredno pod gornjo plastjo kvarcita, verjetno v freatičnih pogojih. Kasnejša erozija v vadozni coni je saprolit odstranila in tako ustvarila mrežo rovov pravokotnega profila. Širjenje rovov je privedlo do rušenja stropa in nastanka podornih dvoran. V glavnem rovu so padli bloki kvarcita zaščitili stene in preprečili nadaljnje spodkopavanje v glavnem rovu jame.Ključne beside: Šri Lanka, gnajs, mreža rovov, saprolit, arenizacija

So near and yet so far: Harmonic radar reveals reduced homing ability of nosema infected honeybees

Pathogens may gain a fitness advantage through manipulation of the behaviour of their hosts. Likewise, host behavioural changes can be a defence mechanism, counteracting the impact of pathogens on host fitness. We apply harmonic radar technology to characterize the impact of an emerging pathogen - Nosema ceranae (Microsporidia) - on honeybee (Apis mellifera) flight and orientation performance in the field. Honeybees are the most important commercial pollinators. Emerging diseases have been proposed to play a prominent role in colony decline, partly through sub-lethal behavioural manipulation of their hosts. We found that homing success was significantly reduced in diseased (65.8%) versus healthy foragers (92.5%). Although lost bees had significantly reduced continuous flight times and prolonged resting times, other flight characteristics and navigational abilities showed no significant difference between infected and non-infected bees. Our results suggest that infected bees express normal flight characteristics but are constrained in their homing ability, potentially compromising the colony by reducing its resource inputs, but also counteracting the intra-colony spread of infection. We provide the first high-resolution analysis of sub-lethal effects of an emerging disease on insect flight behaviour. The potential causes and the implications for both host and parasite are discussed

So near and yet so far: Harmonic radar reveals reduced homing ability of nosema infected honeybees

Pathogens may gain a fitness advantage through manipulation of the behaviour of their hosts. Likewise, host behavioural changes can be a defence mechanism, counteracting the impact of pathogens on host fitness. We apply harmonic radar technology to characterize the impact of an emerging pathogen - Nosema ceranae (Microsporidia) - on honeybee (Apis mellifera) flight and orientation performance in the field. Honeybees are the most important commercial pollinators. Emerging diseases have been proposed to play a prominent role in colony decline, partly through sub-lethal behavioural manipulation of their hosts. We found that homing success was significantly reduced in diseased (65.8%) versus healthy foragers (92.5%). Although lost bees had significantly reduced continuous flight times and prolonged resting times, other flight characteristics and navigational abilities showed no significant difference between infected and non-infected bees. Our results suggest that infected bees express normal flight characteristics but are constrained in their homing ability, potentially compromising the colony by reducing its resource inputs, but also counteracting the intra-colony spread of infection. We provide the first high-resolution analysis of sub-lethal effects of an emerging disease on insect flight behaviour. The potential causes and the implications for both host and parasite are discussed

The Wondrous Bird\u27s Nest I

Translated and annotated by Robert L. Hiller and John C. Osbornehttps://trace.tennessee.edu/utk_newfound-ebooks/1011/thumbnail.jp

Unexpected High Intragenomic Variation in Two of Three Major Pest Thrips Species Does Not Affect Ribosomal Internal Transcribed Spacer 2 (ITS2) Utility for Thrips Identification

The mitochondrial cytochrome oxidase I gene (mtCO1) and the ribosomal internal transcribed spacer 2 region (ITS2) are among the most widely used molecular markers for insect taxonomic characterization. Three economically important species of thrips, Scirtothrips dorsalis, Thrips palmi, and Frankliniella occidentalis were selected to examine the extent of intragenomic variation within these two marker regions in the family Thripidae, and determine if this variation would affect the utility of markers in thrips molecular diagnostics. For each species, intragenomic (within individual) variation and intergenomic (among individuals) variation was assessed by cloning and sequencing PCR-amplified copies. Intergenomic variation was generally higher than intragenomic variation except in cases where intergenomic variation was very low, as in mtCO1 from S. dorsalis and F. occidentalis. Intragenomic variation was detected in both markers in all three of the thrips species, however, 2–3 times more intragenomic variation was observed for ITS2 than mtCO1 in both S. dorsalis and T. palmi. Furthermore, levels of intragenomic variation were low for both of the genes in F. occidentalis. In all of the three thrips species, no sex-based clustering of haplotypes was observed in either marker. Unexpected high intragenomic variation in ITS2 for two of three thrips species did not interfere with thrips diagnostics. However, caution should be taken in applying ITS2 to certain studies of S. dorsalis and T. palmi when high levels of intragenomic variation could be problematic or confounding. In such studies, mtCO1 may be a preferable marker. Possible reasons for discrepancies in intragenomic variation among genomic regions are discussed

Monitoring neonicotinoid exposure for bees in rural and peri-urban areas of the UK during the transition from pre- to post-moratorium

Concerns regarding the impact of neonicotinoid exposure on bee populations recently led to an EU-wide moratorium on the use of certain neonicotinoids on flowering crops. Currently evidence regarding the impact, if any, the moratorium has had on bees’ exposure is limited. We sampled pollen and nectar from bumblebee colonies in rural and peri-urban habitats in three UK regions; Stirlingshire, Hertfordshire and Sussex. Colonies were sampled over three years; prior to the ban (2013), during the initial implementation when some seed-treated winter-sown oilseed rape was still grown (2014), and following the ban (2015). To compare species-level differences, in 2014 only, honeybee colonies in rural habitats were also sampled. Over half of all samples were found to be contaminated (n=408), with thiamethoxam being the compound detected at the highest concentrations in honeybee- (up to 2.29 ng/g in nectar in 2014, median≤0.1 ng/g, n=79) and bumblebee-collected pollen and nectar (up to 38.77 ng/g in pollen in 2013, median ≤0.12 ng/g, n=76). Honeybees were exposed to higher concentrations of neonicotinoids than bumblebees in 2014. While neonicotinoid exposure for rural bumblebees declined post-ban (2015), suggesting a positive impact of the moratorium, the risk of neonicotinoid exposure for bumblebees in peri-urban habitats remained largely the same between 2013 and 2015

Seminar on Evidence and Trial Practice

Outlines of speaker presentations offered during a series of one day seminars on evidence and trial practice offered by UK/CLE in late 1987-early 1988

Disruption of estrogen receptor DNA-binding domain and related intramolecular communication restores tamoxifen sensitivity in resistant breast cancer

SummaryA serious obstacle to successful treatment of estrogen receptor (ER)-positive human breast cancer is cell resistance to tamoxifen (TAM) therapy. Here we show that the electrophile disulfide benzamide (DIBA), an ER zinc finger inhibitor, blocks ligand-dependent and -independent cell growth of TAM-resistant breast cancer in vitro and in vivo. Such inhibition depends on targeting disruption of the ER DNA-binding domain and its communication with neighboring functional domains, facilitating ERα dissociation from its coactivator AIB1 and concomitant association with its corepressor NCoR bound to chromatin. DIBA does not affect phosphorylation of HER2, MAPK, AKT, and AIB1, suggesting that DIBA-modified ERα may induce a switch from agonistic to antagonistic effects of TAM on resistant breast cancer cells