673 research outputs found

    DERIVING SURFACE FUELS FROM UAS IMAGERY FORFIRE MODELS

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    Understanding how fuel, weather, and terrain interact to produce fire behavior continues to motivate fire science andhas resulted in development of new physics-based fire behavior models that place increased demands on input data such as fuels. Recent technological advancements in computing, unmanned aerial systems (UAS), and sensors (RGB, multispectral, thermal, and hyperspectral cameras) can provide new opportunities for land managers and scientists to advance knowledge of fuels and fire behavior and their interactions on the landscape. In this study, imagery from high resolution multispectral cameras mounted on UAS were used to build orthomosaics and point clouds of surface fuelbeds in grass, litter, and shrub fuels of the Sycan Marsh Preserve in Oregon. The purpose of this effort was to develop useful inputs to a fuels translator called STANDFIRE that prepares fuels data for use in physics-based fire models. Fuel type polygons were delineated using traditional photo-interpretation for nine 1 ha plots that were ultimately treated with fire. Each fuel polygon was attributed from field-collected data based on their dominant fuel type. Differences between fuel type polygons were assessed statistically to document the distinctiveness of each fuel type, to overcome field sample-size limitations, and to provide logic for merging fuel types that were similar. Additionally, 3D point clouds and orthomosaics were examined to better understand their information content for more detailed characterizations of fuels. In this latter part of the research, shrub height, width, and cover were extracted from the point clouds and compared to field measurements. The findings were as follows: Defensible fuel type classes were easily delineated using photo-interpretation, resulting in 21.4% of the cumulative plot area classified as litter, 65.3% as grass and 10.3% as shrub fuels. Effective attribution of fuel polygons was dependent on how and where field data were collected and differed by year. Lack of sufficient sample sizes in some fuel type polygons required aggregation of field data from all plots within the Brattain burn unit in 2018. These shortcomings were overcome in 2019 by acquiring rapid-look imagery prior to field sampling that enabled more balanced samples across the range of variability, along with utilization of precision GPS. Within the point-clouds, shrub height was underestimated while width was over-estimated. Shrub cover was also under-predicted from the point cloud and was better enumerated using a conventional dot-grid approach on the orthomosaic. Improvements in data collection methods from 2017-2019 have resulted in a stable workflow that produces consistent fuels data formatted for STANDFIRE. The polygon-based approach is suitable for use in fire model validation due to its ability to rationally integrate sparse field data, because STANDFIRE is designed to work easily with polygons, and because there is insufficient evidence that model validation is at a point where it will benefit from use of more complex pixel or object-based inputs. Automated approaches to polygon delineation via region-growing, machine learning, and segmentation are a logical next step, with the caveat that the inputs derived in this study should be tested in the modeling environment first

    Optimization of Indium Bump Morphology for Improved Flip Chip Devices

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    Flip-chip hybridization, also known as bump bonding, is a packaging technique for microelectronic devices that directly connects an active element or detector to a substrate readout face-to-face, eliminating the need for wire bonding. In order to make conductive links between the two parts, a solder material is used between the bond pads on each side. Solder bumps, composed of indium metal, are typically deposited by thermal evaporation onto the active regions of the device and substrate. While indium bump technology has been a part of the electronic interconnect process field for many years and has been extensively employed in the infrared imager industry, obtaining a reliable, high-yield process for high-density patterns of bumps can be quite difficult. Under the right conditions, a moderate hydrogen plasma exposure can raise the temperature of the indium bump to the point where it can flow. This flow can result in a desirable shape where indium will efficiently wet the metal contact pad to provide good electrical contact to the underlying readout or imager circuit. However, it is extremely important to carefully control this process as the intensity of the hydrogen plasma treatment dramatically affects the indium bump morphology. To ensure the fine-tuning of this reflow process, it is necessary to have realtime feedback on the status of the bumps. With an appropriately placed viewport in a plasma chamber, one can image a small field (a square of approximately 5 millimeters on each side) of the bumps (10-20 microns in size) during the hydrogen plasma reflow process. By monitoring the shape of the bumps in real time using a video camera mounted to a telescoping 12 magnifying zoom lens and associated optical elements, an engineer can precisely determine when the reflow of the bumps has occurred, and can shut off the plasma before evaporation or de-wetting takes place

    Self-administered behavioral family intervention for parents of toddlers: Part I. Efficacy

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    This study examined the efficacy of a self-administered behavioral family intervention for 126 parents of toddlers. The effects of 2 different levels of intensity of the self-administered intervention were contrasted (self-administered alone or self-administered plus brief therapist telephone assistance). The results provide support for the efficacy of the self-administered form of behavioral family intervention. There were significant short-term reductions in reported child behavior problems and improvements in maternal parenting style, parenting confidence, and anger. Families who received minimal therapist assistance made more clinically significant gains compared with families who completed the program with no therapist assistance. The intervention effects were maintained at 6-month follow-up. The implications of the findings for the population-level delivery of behavioral family interventions are discussed

    Protease-activated receptor 4 variant p.Tyr157Cys reduces platelet functional responses and alters receptor trafficking

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    OBJECTIVE—: Protease-activated receptor 4 (PAR4) is a key regulator of platelet reactivity and is encoded by F2RL3, which has abundant rare missense variants. We aimed to provide proof of principle that rare F2LR3 variants potentially affect on platelet reactivity and responsiveness to PAR1 antagonist drugs and to explore underlying molecular mechanisms. APPROACH AND RESULTS—: We identified 6 rare F2RL3 missense variants in 236 cardiac patients, of which the variant causing a tyrosine 157 to cysteine substitution (Y157C) was predicted computationally to affect most on PAR4 structure. Y157C platelets from 3 cases showed reduced responses to PAR4-activating peptide and to α-thrombin compared with controls, but no reduction in responses to PAR1-activating peptide. Pretreatment with the PAR1 antagonist vorapaxar caused lower residual α-thrombin responses in Y157C platelets than in controls, indicating greater platelet inhibition. HEK293 cells transfected with a PAR4 Y157C expression construct had reduced PAR4 functional responses, unchanged total PAR4 expression but reduced surface expression. PAR4 Y157C was partially retained in the endoplasmic reticulum and displayed an expression pattern consistent with defective N-glycosylation. Mutagenesis of Y322, which is the putative hydrogen bond partner of Y157, also reduced PAR4 surface expression in HEK293 cells. CONCLUSIONS—: Reduced PAR4 responses associated with Y157C result from aberrant anterograde surface receptor trafficking, in part, because of disrupted intramolecular hydrogen bonding. Characterization of PAR4 Y157C establishes that rare F2RL3 variants have the potential to markedly alter platelet PAR4 reactivity particularly after exposure to therapeutic PAR1 antagonists

    Sparsely-Bonded CMOS Hybrid Imager

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    A method and device for imaging or detecting electromagnetic radiation is provided. A device structure includes a first chip interconnected with a second chip. The first chip includes a detector array, wherein the detector array comprises a plurality of light sensors and one or more transistors. The second chip includes a Read Out Integrated Circuit (ROIC) that reads out, via the transistors, a signal produced by the light sensors. A number of interconnects between the ROIC and the detector array can be less than one per light sensor or pixel

    Growth and mass wasting of volcanic centers in the northern South Sandwich arc, South Atlantic, revealed by new multibeam mapping

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    New multibeam (swath) bathymetric sonar data acquired using an EM120 system on the RRS James Clark Ross, supplemented by sub-bottom profiling, reveals the underwater morphology of a not, vert, similar 12,000 km2 area in the northern part of the mainly submarine South Sandwich volcanic arc. The new data extend between 55° 45′S and 57° 20′S and include Protector Shoal and the areas around Zavodovski, Visokoi and the Candlemas islands groups. Each of these areas is a discrete volcanic center. The entirely submarine Protector Shoal area, close to the northern limit of the arc, forms a 55 km long east–west-trending seamount chain that is at least partly of silicic composition. The seamounts are comparable to small subaerial stratovolcanoes in size, with volumes up to 83 km3, indicating that they are the product of multiple eruptions over extended periods. Zavodovski, Visokoi and the Candlemas island group are the summits of three 3–3.5 km high volcanic edifices. The bathymetric data show evidence for relationships between constructional volcanic features, including migrating volcanic centers, structurally controlled constructional ridges, satellite lava flows and domes, and mass wasting of the edifices. Mass wasting takes place mainly by strong erosion at sea level, and dispersal of this material along chutes, probably as turbidity currents and other mass flows that deposit in extensive sediment wave fields. Large scale mass wasting structures include movement of unconsolidated debris in slides, slumps and debris avalanches. Volcanism is migrating westward relative to the underlying plate and major volcanoes are asymmetrical, being steep with abundant recent volcanism on their western flanks, and gently sloping with extinct, eroded volcanic sequences to their east. This is consistent with the calculated rate of subduction erosion of the fore-arc

    Multiple emergences of genetically diverse amphibian-infecting chytrids include a globalized hypervirulent recombinant lineage

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    Batrachochytriumdendrobatidis (Bd) is a globally ubiquitous fungal infection that has emerged to become a primary driver of amphibian biodiversity loss. Despite widespread effort to understand the emergence of this panzootic, the origins of the infection, its patterns of global spread, and principle mode of evolution remain largely unknown. Using comparative population genomics, we discovered three deeply diverged lineages of Bd associated with amphibians. Two of these lineages were found in multiple continents and are associated with known introductions by the amphibian trade.We found that isolates belonging to one clade, the global panzootic lineage (BdGPL) have emerged across at least five continents during the 20th century and are associated with the onset of epizootics in North America, Central America, the Caribbean, Australia, and Europe. The two newly identified divergent lineages, Cape lineage (BdCAPE) and Swiss lineage (BdCH), were found to differ in morphological traits when compared against one another and BdGPL, and we show that BdGPL is hypervirulent. BdGPL uniquely bears the hallmarks of genomic recombination, manifested as extensive intergenomic phylogenetic conflict and patchily distributed heterozygosity. Wepostulate that contact between previously genetically isolated allopatric populations of Bd may have allowed recombination to occur, resulting in the generation, spread, and invasion of the hypervirulent BdGPL leading to contemporary disease-driven losses in amphibian biodiversity.Peer Reviewe

    Differential timing of antibody-mediated phagocytosis and cell-free killing of invasive African Salmonella allows immune evasion

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    Nontyphoidal Salmonellae commonly cause fatal bacteraemia in African children lacking anti-Salmonella antibodies. These are facultative intracellular bacteria capable of cell-free and intracellular survival within macrophages. To better understand the relationship between extracellular and intracellular infection in blood and general mechanisms of Ab-related protection against Salmonella, we used human blood and sera to measure kinetics of Ab and complement deposition, serum-mediated bactericidal killing and phagocytosis of invasive African Salmonella enterica serovar Typhimurium D23580. Binding of antibodies peaked by 30 s, but C3 deposition lagged behind, peaking after 2-4 min. C5b-9 deposition was undetectable until between 2 and 6 min and peaked after 10 min, after which time an increase in serum-mediated killing occurred. In contrast, intracellular, opsonized Salmonellae were readily detectable within 5 min. By 10 min, around half of monocytes and most neutrophils contained bacteria. The same kinetics of serum-mediated killing and phagocytosis were observed with S. enterica Typhimurium laboratory strain SL1344, and the S. enterica Enteritidis African invasive isolate D24954 and laboratory strain PT4. The differential kinetics between cell-free killing and phagocytosis of invasive nontyphoidal Salmonella allows these bacteria to escape the blood and establish intracellular infection before they are killed by the membrane attack complex
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