35 research outputs found
The potential of small unmanned aircraft systems and structure-from-motion for topographic surveys: a test of emerging integrated approaches at Cwm Idwal, North Wales
This paper was accepted for publication in the journal Geomorphology and the definitive published version is available at http://dx.doi.org/10.1016/j.geomorph.2014.07.021Novel topographic survey methods that integrate both structure-from-motion (SfM) photogrammetry and small unmanned aircraft systems (sUAS) are a rapidly evolving investigative technique. Due to the diverse range of survey configurations available and the infancy of these new methods, further research is required. Here, the accuracy, precision and potential applications of this approach are investigated. A total of 543 images of the Cwm Idwal moraine–mound complex were captured from a light (b5 kg) semi-autonomous multi-rotor unmanned aircraft system using a consumer-grade 18 MP compact digital camera. The imageswere used to produce a DSM(digital surfacemodel) of themoraines. The DSMis in good agreement with 7761 total station survey points providing a total verticalRMSE value of 0.517mand verticalRMSE values as lowas 0.200mfor less densely vegetated areas of the DSM. High-precision topographic data can be acquired rapidly using this technique with
the resulting DSMs and orthorectified aerial imagery at sub-decimetre resolutions. Positional errors on the total station dataset, vegetation and steep terrain are identified as the causes of vertical disagreement. Whilst this aerial survey approach is advocated for use in a range of geomorphological settings, care must be taken to ensure that adequate ground control is applied to give a high degree of accuracy
PAM50 molecular intrinsic subtypes in the nurses' health Study cohorts
Background: Modified median and subgroup-specific gene subtypes by PAM50 and IHC surrogates improved to fair centering are two essential preprocessing methods to assign when Luminal subtypes were grouped together. Using the breast cancer molecular subtypes by PAM50. We evaluated the modified median method, our study consisted of 46% PAM50 subtypes derived from both methods in a subset of Luminal A, 18% Luminal B, 14% HER2-enriched, 15% Nurses' Health Study (NHS) and NHSII participants; correlat-Basal-like, and 8% Normal-like subtypes; 53% of tumor-ed tumor subtypes by PAM50 with IHC surrogates; and adjacent tissues were Normal-like. Women with the Basal-characterized the PAM50 subtype distribution, proliferation like subtype had a higher rate of relapse within 5 years. scores, and risk of relapse with proliferation and tumor size HER2-enriched subtypes had poorer outcomes prior to weighted (ROR-PT) scores in the NHS/NHSII. 1999. Methods: PAM50 subtypes, proliferation scores, and Conclusions: Either preprocessing method may be uti-ROR-PT scores were calculated for 882 invasive breast tumors lized to derive PAM50 subtypes for future studies. The and 695 histologically normal tumor-adjacent tissues. Cox majority of NHS/NHSII tumor and tumor-adjacent tissues proportional hazards models evaluated the relationship were classified as Luminal A and Normal-like, respectively. between PAM50 subtypes or ROR-PT scores/groups with Impact: Preprocessing methods are important for the recurrence-free survival (RFS) or distant RFS. accurate assignment of PAM50 subtypes. These data provide Results: PAM50 subtypes were highly comparable evidence that either preprocessing method can be used in between the two methods. The agreement between tumor epidemiologic studies
An introduction to the SCOUT-AMMA stratospheric aircraft, balloons and sondes campaign in West Africa, August 2006: rationale and roadmap
A multi-platform field measurement campaign involving aircraft and balloons took place over West Africa between 26 July and 25 August 2006, in the frame of the concomitant AMMA Special Observing Period and SCOUT-O3 African tropical activities.
Specifically aiming at sampling the upper troposphere and lower stratosphere, the high-altitude research aircraft M55 Geophysica was deployed in Ouagadougou (12.3° N, 1.7° W), Burkina Faso, in conjunction with the German D-20 Falcon, while a series of stratospheric balloon and sonde flights were conducted from Niamey (13.5° N, 2.0° E), Niger.
The stratospheric aircraft and balloon flights intended to gather experimental evidence for a better understanding of large scale transport, assessing the effect of lightning on NOx production, and studying the impact of intense mesoscale convective systems on water, aerosol, dust and chemical species in the upper troposphere and lower stratosphere. The M55 Geophysica carried out five local and four transfer flights between southern Europe and the Sahel and back, while eight stratospheric balloons and twenty-nine sondes were flown from Niamey.
These experiments allowed a characterization of the tropopause and lower stratosphere of the region. We provide here an overview of the campaign activities together with a description of the general meteorological situation during the flights and a summary of the observations accomplished
Antarctica and environmental change. Proceedings of a Royal Society discussion meeting. May 1992
Evolution and chronology of the Pangong Metamorphic Complex adjacent to the Karakoram Fault, Ladakh : constraints from thermobarometry, metamorphic modelling and U-Pb geochronology
Sillimanite- and staurolite-grade metamorphic rocks exhumed along the Pangong fault, the NE branch of the right-lateral Karakoram strike-slip fault in northern Ladakh, NW India, show multiple episodes of metamorphism and fabric development. Debate has centred on whether these metamorphic rocks were formed as a result of shear heating during strike-slip faulting, or whether they are exhumed earlier metamorphic rocks unrelated to movement on the Karakoram fault. Here we constrain the burial and exhumation history of the Pangong Metamorphic Complex combining the pressure–temperature evolution with accessory phase geochronology. Sillimanite-grade metamorphism in graphitic pelites was superseded by the preserved P–T conditions of a Bt + Ms + St + Grt + Qtz + Fsp assemblage at 585–605 °C and 6.05–7.25 kbar, equivalent to c. 20–25 km of burial. Laser ablation monazite U–Pb geochronology reveals that sillimanite-grade metamorphism occurred at 108.0 ± 0.6 Ma in rocks immediately adjacent to the Pangong strand of the Karakoram fault, implying that most metamorphic rocks along the Karakoram fault were not formed by shear heating during Miocene strike-slip faulting. This age correlates closely with the ages of the Hunza granite–granodiorite batholith, and the K2 orthogneiss in northern Pakistan, and confirms that some high-grade metamorphism occurred before collision and accretion of the Kohistan arc and the Indian plate to Asia; protracted high-grade metamorphism, and accompanying crustal thickening lasted at least 100 Ma along the South Asian plate margin. Our P–T and geochronology results also demonstrate the continuity of Cretaceous metamorphism across the Karakoram fault
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Neutron production by neutral beam sources
Neutron yields, from interactions of multiampere 40- to 120-keV deuterium beams with deuterium atoms implanted in copper targets, have been measured in order to provide input data for shielding of neutral-deuterium beam facilities for magnetic fusion experiments