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The McMurdo shear zone (MSZ) is strip of heavily crevassed ice oriented in the south-north direction and moving northward. Previous airborne surveys revealed a chaotic crevasse structure superimposed on a set of expected crevasse orientations at 45 degrees to the south-north flow (due to shear stress mechanisms). The dynamics that produced this chaotic structure are poorly understood. Our purpose is to present our field methodology and provide field data that will enable validation of models of the MSZ evolution, and here, we present a method for deriving a local velocity field from ground penetrating radar (GPR) data towards that end. Maps of near-surface crevasses were derived from two annual GPR surveys of a 28 km² region of the MSZ using Eulerian sampling. Our robot-towed and GPS navigated GPR enabled a dense survey grid, with transects of the shear zone at 50 m spacing. Each survey comprised multiple crossings of long (> 1 km) crevasses that appear in echelon on the western and eastern boundaries of the shear zone, as well as two or more crossings of shorter crevasses in the more chaotic zone between the western and eastern boundaries. From these maps, we derived a local velocity field based on the year-to-year movement of the same crevasses. Our velocity field varies significantly from fields previously established using remote sensing and provides more detail than one concurrently derived from a 29-station GPS network. Rather than a simple velocity gradient expected for crevasses oriented approximately 45 degrees to flow direction, we find constant velocity contours oriented diagonally across the shear zone with a wavy fine structure. Although our survey is based on near-surface crevasses, similar crevassing found in marine ice at 160 m depth leads us to conclude that this surface velocity field may hold through the body of meteoric and marine ice. Our success with robot-towed GPR with GPS navigation suggests we may greatly increase our survey areas.

The crevassed firn of the McMurdo shear zone (SZ) within the Ross Ice Shelf may also contain crevasses deep within its meteoric and marine ice, but the surface crevassing prevents ordinary vehicle access to investigate its structure geophysically. We used a lightweight robotic vehicle to tow 200- and 40 MHz ground-penetrating radar antennas simultaneously along 10 parallel transects over a 28 km² grid spanning the SZ width. Transects were generally orthogonal to the ice flow. Total firn and meteoric ice thickness was approximately 160 m. Firn crevasses profiled at 400 MHz were up to 16 m wide, under snow bridges up to 10 m thick, and with strikes near 35°–40° to the transect direction. From the top down, 200- MHz profiles revealed firn diffractions originating to a depth of approximately 40 m, no discernible structure within the meteoric ice, a discontinuous transitional horizon, and at least 20 m of stratified marine ice; 28–31 m of freeboard found more marine ice exists. Based on 10 consecutive transects covering approximately 2.5 km², we preliminarily interpreted the transitional horizon to be a thin saline layer, and marine ice hyperbolic diffractions and reflections to be responses to localized fractures, and crevasses filled with unstratified marine ice, all at strikes from 27° to 50°. We preliminarily interpreted off nadir, marine ice horizons to be responses to linear and folded faults, similar to some in firn. The coinciding and synchronously folded areas of fractured firn and marine ice suggested that the visibly unstructured meteoric ice beneath our grid was also fractured, but either never crevassed, crevassed and sutured without marine ice inclusions, or that any ice containing crevasses might have eroded before marine ice accretion. We will test these interpretations with analysis of all transects and by extending our grid and increasing our depth ranges.

Accurate decoding of nucleic acid variation is critical to understand the complexity and regulation of genome function. Here we use a single-molecule magnetic tweezer (MT) platform to identify sequence variation and map a range of important epigenetic base modifications with high sensitivity, specificity, and precision in the same single molecules of DNA or RNA. We have also developed a highly specific amplification-free CRISPR-Cas enrichment strategy to isolate genomic regions from native DNA. We demonstrate enrichment of DNA from both E. coli and the FMR1 5’UTR coming from cells derived from a Fragile X carrier. From these kilobase-length enriched molecules we could characterize the differential levels of adenine and cytosine base modifications on E. coli, and the repeat expansion length and methylation status of FMR1. Together these results demonstrate that our platform can detect a variety of genetic, epigenetic, and base modification changes concomitantly within the same single molecules., Wang et al. show how genetic sequence and base modifications can be detected simultaneously on single molecules of both DNA and RNA using magnetic tweezers. They also demonstrate an amplification-free CRISPR/Cas9-based strategy for isolating target regions from native DNA and apply this approach to the isolation of targets from E. coli and human genomic DNA.

This thesis mixes the disciplines of sociolinguistics, media and minority language studies. Over the past decade the availability and prominence of Gaelic television in Scotland has significantly increased through the launch of Scotland’s first stand-alone Scottish Gaelic television channel – BBC Alba. The presence of Minority Language Media (MLM) is popularly considered as an important element of efforts at maintaining and revitalising minority languages, however the ways in which the language in question actually benefits is keenly debated but still largely unknown. Studies by Moriarty (2007) showed that is media impact upon minority language indirect and is mediated through language attitudes whilst De. Bres (2008) discovered that MLM normalises the language amongst the majority language dominated society through promotion of positive attitudes and behaviours. This study concentrates on viewers of BBC Alba, sampling a sports viewing population. The study deploys a mixed method approach of both qualitative and quantitative methods. The quantitative element revealed stronger correlations between attitudinal positivity and favourability towards Gaelic than had been previously discovered in other studies such as (West & Graham: 2011) and O’ Hanlon & Paterson (2012). The qualitative element revealed strong connections to issues of identity and Gaelic, whilst the promotion of Gaelic services especially Gaelic-medium education were topics of repeated participant discussion. Analysis of the overall data concludes that exposure to Gaelic television by the majority language population raises the status of the language in wider society, promoting a healthy acceptance of bilingualism in Scottish society ultimately fostering an improved linguistic environment for Scottish Gaelic to be sustained for future generations.

SummaryWe present a middle school problem and generalize it in several ways, including many new variations for readers to explore. The problems should be attractive to students, as they have few prerequisites and lend themselves to beautiful visual representations.

The sandfly,Lutzomyia longipalpis (Lutz and Neiva), produces an oviposition pheromone in the accessory glands that is secreted onto the eggs during oviposition. This compound attracts and/or stimulates gravid females for egg-laying. The compound was identified as dodecanoic acid, using gas chromatography–mass spectrometry, gas chromatography, and chemical derivatizations. The synthetic analog induced the same behavioral response in gravid sandflies as the whole egg extract when present in biologically relevant quantities. When single sensillum recordings were taken from the ascoid on the antennae of female sandflies, the response to egg extract and dodecanoic acid was similar. There was a dose dependent response to dodecanoic acid and preferential sensitivity compared to other fatty acids. There was a strong additive interaction upon the behavior ofL. longipalpis when dodecanoic acid was tested in a bioassay with the known oviposition attractant apneumones from rabbit feces, hexanal, and 2-methyl-2-butanol. The results suggested that sandflies acquired hexadecanoic acid (palmitic acid) from the blood meal and over a period of four days this was converted to dodecanoic acid. The role of these “token” semiochemicals in sandfly oviposition is discussed with respect to additive interactions and the significance of their origin from larval food resources.

Antibody (IgG) responses to the saliva of Phlebotomus argentipes were investigated using serum samples from regions of India endemic and non-endemic for visceral leishmaniasis (VL). By pre-adsorbing the sera against the saliva of the competing human-biting but non-VL vector P. papatasi, we significantly improved the specificity of a P. argentipes saliva enzyme-linked immunosorbent assay. Using this method, we observed a statistically significant correlation between antibodies to P. argenitpes saliva and the average indoor density of female sand flies. Additionally, the method was able to detect recent changes in vector exposure when sera from VL patients were assayed before, during, and after hospitalization and protected from sand fly bites under untreated bed nets. Collectively, these results highlight the utility of antibodies to P. argentipes saliva as an important tool to evaluate VL vector control programs.

The phlebotomine sandflyLutzomyia longipalpis Lutz and Neiva, the vector of visceral leishmaniasis in South America, has recently been shown to produce an oviposition semiochemical. In the present study it was found that a nonpolar extract of eggs was attractive and/or stimulatory to ovipositing females. A Chromatographic investigation indicated the presence of similar compounds in accessory glands and egg extracts. Extract of accessory gland was also found to elicit a positive oviposition response. It is concluded that the pheromone is produced in the accessory glands and is secreted onto the eggs during oviposition.

The results are reported of lumbar epidurography in 110 patients suffering from low back pain. By using the water-soluble non-ionic contrast metrizamide, it has been possible to perform the examination on an outpatient basis. None of the patients has suffered from headache, nor any other complaint often associated with other diagnostic techniques which involve lumbar puncture. Epidurography is sufficiently accurate to be regarded as the examination of choice in the diagnosis of lumbar disc prolapse.

An improved technique of epidurography using metrizamide is described. Fifty patients were examined in order to establish whether the technique can be satisfactorily performed as an outpatient procedure and whether it is as useful as radiculography. The findings indicate that metrizamide epidurography is a safe examination, providing at least as much information as radiculography. Our patients tolerated the examination well, avoiding the after effects associated with intradural techniques, and were able to leave hospital a few hours later. No untoward sequelae occurred.