72 research outputs found
Remote Predictive Mapping 7. The Use of TopographicâBathymetric Lidar to Enhance Geological Structural Mapping in Maritime Canada
An airborne topo-bathymetric lidar survey was conducted at Cape John, on the north shore of Nova Scotia, Canada, using the shallow water Leica AHAB Chiroptera II sensor. The survey revealed new bedrock features that were not discovered using previous mapping methods. A thick blanket of glacial till covers the bedrock on land, and outcrops are exposed only along the coastal cliffs and offshore reefs. The seamless landseabed digital elevation model produced from the lidar survey revealed significant bedrock outcrop offshore where ocean currents have removed the glacial till, a significant finding that was hitherto hidden under the sea surface. Several reefs were identified offshore as well as a major fold structure where block faulting occurs along the limbs of the fold. The extension of the Malagash Mine Fault located ~10 km west of Cape John is proposed to explain the local folding and faulting visible in the submerged outcrops. The extension of this fault is partially visible on land, where it is obscured by glacial till, and its presence is supported by the orientation of submerged bedding and lineaments on both the south and north sides of Cape John. This paper demonstrates how near-shore high-resolution topography from bathymetric lidar can be used to enhance and refine geological mapping.RĂSUMĂUn levĂ© lidar topo-bathymĂ©trique Ă©tĂ© rĂ©alisĂ© Ă Cape John, sur la rive nord de la Nouvelle-Ăcosse, Canada, en utilisant un capteur Leci AHAB Chiroptera II. Ce levĂ© a permis de repĂ©rer des affleurements que les mĂ©thodes de cartographie plus anciennes nâavaient pu dĂ©tecter. Une Ă©paisse couche de till glaciaire recouvre la roche en place sur le continent, et la roche affleure seulement le long des falaises cĂŽtiĂšres et des rĂ©cifs cĂŽtiers. Le modĂšle numĂ©rique de dĂ©nivelĂ© en continu terres et fonds marins obtenu par le levĂ© lidar a rĂ©vĂ©lĂ© lâexistence dâaffleurement rocheux considĂ©rables au large des cĂŽtes, lĂ oĂč les courants ocĂ©aniques ont emportĂ© le till glaciaire, une dĂ©couverte importante demeurĂ©e cachĂ©e sous la surface de la mer jusquâalors. Plusieurs rĂ©cifs ont Ă©tĂ© identifiĂ©s au large des cĂŽtes, ainsi quâune structure de pli majeure, Ă lâendroit oĂč se produit un morcellement en blocs le long des flancs du pli. Une extension de la faille de la mine Malagash situĂ© ~ 10 km Ă lâouest de Cape John est proposĂ© pour expliquer les plis et les failles locaux visibles dans les affleurements submergĂ©s. Lâextension de cette faille est partiellement visible sur la terre, voilĂ©e par le till, et sa prĂ©sence est Ă©tayĂ©e par lâorientation de la stratification et des linĂ©aments submergĂ©s tant du cĂŽtĂ© sud que nord de Cape John. Cet article montre comment la topographie haute rĂ©solution du lidar bathymĂ©trique peut ĂȘtre utilisĂ©e pour amĂ©liorer et affiner la cartographie gĂ©ologique
Dynamic detection of electron spin accumulation in ferromagnet-semiconductor devices by ferromagnetic resonance
A distinguishing feature of spin accumulation in ferromagnet-semiconductor
devices is precession of the non-equilibrium spin population of the
semiconductor in a magnetic field. This is the basis for detection techniques
such as the Hanle effect, but these approaches become less effective as the
spin lifetime in the semiconductor decreases. For this reason, no electrical
Hanle measurement has been demonstrated in GaAs at room temperature. We show
here that by forcing the magnetization in the ferromagnet (the spin injector
and detector) to precess at the ferromagnetic resonance frequency, an
electrically generated spin accumulation can be detected from 30 to 300 K. At
low temperatures, the distinct Larmor precession of the spin accumulation in
the semiconductor can be detected by ferromagnetic resonance in an oblique
field. We verify the effectiveness of this new spin detection technique by
comparing the injection bias and temperature dependence of the measured spin
signal to the results obtained using traditional methods. We further show that
this new approach enables a measurement of short spin lifetimes (< 100 psec), a
regime that is not accessible in semiconductors using traditional Hanle
techniques.Comment: 4 figure
On the ability of space-based passive and active remote sensing observations of CO2 to detect flux perturbations to the carbon cycle
Author Posting. © American Geophysical Union, 2018. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Atmospheres 123 (2018): 1460â1477, doi:10.1002/2017JD027836.Space-borne observations of CO2 are vital to gaining understanding of the carbon cycle in regions of the world that are difficult to measure directly, such as the tropical terrestrial biosphere, the high northern and southern latitudes, and in developing nations such as China. Measurements from passive instruments such as GOSAT and OCO-2, however, are constrained by solar zenith angle limitations as well as sensitivity to the presence of clouds and aerosols. Active measurements such as those in development for the Active Sensing of CO2 Emissions over Nights, Days and Seasons (ASCENDS) mission show strong potential for making measurements in the high-latitude winter and in cloudy regions. In this work we examine the enhanced flux constraint provided by the improved coverage from an active measurement such as ASCENDS. The simulation studies presented here show that with sufficient precision, ASCENDS will detect permafrost thaw and fossil fuel emissions shifts at annual and seasonal time scales, even in the presence of transport errors, representativeness errors, and biogenic flux errors. While OCO-2 can detect some of these perturbations at the annual scale, the seasonal sampling provided by ASCENDS provides the stronger constraint.NASA Grant Numbers: NNX15AJ27G, NNX15AH13G2018-07-2
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Implementation of and Early Outcomes From Anal Cancer Screening at a Community-Engaged Health Care Facility Providing Care to Nigerian Men Who Have Sex With Men.
PurposeAnal cancer risk is substantially higher among HIV-infected men who have sex with men (MSM) as compared with other reproductive-age adults, but screening is rare across sub-Saharan Africa. We report the use of high-resolution anoscopy (HRA) as a first-line screening tool and the resulting early outcomes among MSM in Abuja, Nigeria.MethodsFrom August 2016 to August 2017, 424 MSM enrolled in an anal cancer screening substudy of TRUST/RV368, a combined HIV prevention and treatment cohort. HRA-directed biopsies were diagnosed by histology, and ablative treatment was offered for high-grade squamous intraepithelial lesions (HSIL). HRA proficiency was assessed by evaluating the detection of squamous intraepithelial lesions (SIL) over time and the proportion biopsied. Prevalence estimates of low-grade squamous intraepithelial lesions and HSIL with 95% CIs were calculated. Multinomial logistic regression was used to identify those at the highest risk of SIL.ResultsMedian age was 25 years (interquartile range [IQR], 22-29), median time since sexual debut was 8 years (IQR, 4-12), and 59% (95% CI, 54.2% to 63.6%) were HIV infected. Rate of detection of any SIL stabilized after 200 screenings, and less than 20% had two or more biopsies. Preliminary prevalence estimates of low-grade squamous intraepithelial lesions and HSIL were 50.0% (95% CI, 44.7% to 55.3%) and 6.3% (95% CI, 4.0% to 9.3%). HIV infection, at least 8 years since anal coital debut, concurrency, and external warts were independently statistically associated with SIL.ConclusionProficiency with HRA increased with experience over time. However, HSIL detection rates were low, potentially affected by obstructed views from internal warts and low biopsy rates, highlighting the need for ongoing evaluation and mentoring to validate this finding. HRA is a feasible first-line screening tool at an MSM-friendly health care facility. Years since anal coital debut and external warts could prioritize screening
PenQuest Volume 5, Number 1
Table of Contents for this Volume:
Success by Shatney
Maria by Jane OâNeal
Intrusions by Mark McBride
The Mystery of the Back Porch Light by Nature Johnston
Truth and the Violin by Shatney
Corporate America by Julie Crowell
Peteâs Cafe by Nature Johnston
Geranium by Anne Benjamin
The Man Who Buried His Books by William Slaughter
Erasures by William Slaughter
Mind You and other poems by Kate Mathews
Coffee in the Tea Room by Kathleen OâBrien
The Children by Katharine Rodier
Sisters, Reclamation, Not Wanting to Say, âI Told You So,â But⊠by Kathleen OâBrien
Genetics by Kathleen OâBrien
The Anguish of Flames by Kathleen OâBrien
turning plows by Mark McBride
A Valediction for My Father by Jonathan Williams
Untitled by Mark Sablow
Artificial Portrait by Kevin Christenson
Untitled by Latrell Mickler
Untitled by Kevin Christenson
Galvanistic Ascension by Mark Grisham
Power Surge by Mark Grisham
Untitled by Lori Kirsbau
National CO\u3csub\u3e2\u3c/sub\u3e budgets (2015-2020) inferred from atmospheric CO\u3csub\u3e2\u3c/sub\u3e observations in support of the global stocktake
Accurate accounting of emissions and removals of CO2 is critical for the planning and verification of emission reduction targets in support of the Paris Agreement. Here, we present a pilot dataset of country-specific net carbon exchange (NCE; fossil plus terrestrial ecosystem fluxes) and terrestrial carbon stock changes aimed at informing countries\u27 carbon budgets. These estimates are based on top-down NCE outputs from the v10 Orbiting Carbon Observatory (OCO-2) modeling intercomparison project (MIP), wherein an ensemble of inverse modeling groups conducted standardized experiments assimilating OCO-2 column-Averaged dry-Air mole fraction (XCO2) retrievals (ACOS v10), in situ CO2 measurements or combinations of these data. The v10 OCO-2 MIP NCE estimates are combined with bottom-up estimates of fossil fuel emissions and lateral carbon fluxes to estimate changes in terrestrial carbon stocks, which are impacted by anthropogenic and natural drivers. These flux and stock change estimates are reported annually (2015-2020) as both a global 1ggĂg1g gridded dataset and a country-level dataset and are available for download from the Committee on Earth Observation Satellites\u27 (CEOS) website: 10.48588/npf6-sw92 . Across the v10 OCO-2 MIP experiments, we obtain increases in the ensemble median terrestrial carbon stocks of 3.29-4.58gPgCO2yr-1 (0.90-1.25gPgCyr-1). This is a result of broad increases in terrestrial carbon stocks across the northern extratropics, while the tropics generally have stock losses but with considerable regional variability and differences between v10 OCO-2 MIP experiments. We discuss the state of the science for tracking emissions and removals using top-down methods, including current limitations and future developments towards top-down monitoring and verification systems
The use of imepitoin (Pexionâą) on fear and anxiety related problems in dogs â a case series
Fear and anxiety based problems are common in dogs. Alongside behaviour modification programmes, a range of psychopharmacological agents may be recommended to treat such problems, but few are licensed for use in dogs and the onset of action of some can be delayed. The low affinity partial benzodiazepine receptor agonist imepitoin (Pexionâą, Boehringer Ingelheim) is licensed for treating canine epilepsy, has a fast onset of action in dogs and has demonstrated anxiolytic properties in rodent models. This case series reports on the use of imepitoin in a group of dogs identified as having fear/anxiety based problems. Twenty dogs were enrolled into the study, attended a behaviour consultation and underwent routine laboratory evaluation. Nineteen dogs proceeded to be treated with imepitoin orally twice daily (starting dose approximately 10 mg/kg, with alterations as required to a maximum 30 mg/kg) alongside a patient-specific behaviour modification plan for a period of 11â19 weeks. Progress was monitored via owner report through daily diary entries and telephone follow-up every two weeks. A Positive and Negative Activation Scale (PANAS) of temperament was also completed by owners during baseline and at the end of the study
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