251 research outputs found
Aircraft remote sensing of phytoplankton spatial patterns during the 1989 Joint Global Ocean Flux Study (JGOFS) North Atlantic bloom experiment
Mesoscale phytoplankton chlorophyll variability near the Joint Global Ocean Flux study sites along the 20 W meridian at 34 N, 47 N, and 59 N is discussed. The NASA P-3 aircraft and the Airborne Oceanographic Lidar (AOL) system provides remote sensing support for the North Atlantic Bloom Experiment. The principal instrument of the AOL system is the blue-green laser that stimulates fluorescence from photoplankton chlorophyll, the principal photosynthetic pigment. Other instruments on the NASA P-3 aircraft include up- and down-looking spectrometers, PRT-5 for infrared measurements to determine sea surface temperature, and a system to deploy and record AXBTs to measure subsurface temperature structure
Multi-Antenna Vision-and-Inertial-Aided CDGNSS for Micro Aerial Vehicle Pose Estimation
A system is presented for multi-antenna carrier phase differential GNSS (CDGNSS)-based pose (position and orientation) estimation aided by monocular visual measurements and a smartphone-grade inertial sensor. The system is designed for micro aerial vehicles, but can be applied generally for low-cost, lightweight, high-accuracy, geo-referenced pose estimation. Visual and inertial measurements enable robust operation despite GNSS degradation by constraining uncertainty in the dynamics propagation, which improves fixed-integer CDGNSS availability and reliability in areas with limited sky visibility. No prior work has demonstrated an increased CDGNSS integer fixing rate when incorporating visual measurements with smartphone-grade inertial sensing. A central pose estimation filter receives measurements from separate CDGNSS position and attitude estimators, visual feature measurements based on the ROVIO measurement model, and inertial measurements. The filter's pose estimates are fed back as a prior for CDGNSS integer fixing. A performance analysis under both simulated and real-world GNSS degradation shows that visual measurements greatly increase the availability and accuracy of low-cost inertial-aided CDGNSS pose estimation.Aerospace Engineering and Engineering Mechanic
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Open-World Virtual Reality Headset Tracking
A novel outdoor Virtual Reality (VR) concept called Open-World Virtual Reality (OWVR) is presented that combines precise GNSS positioning and a smartphone-grade inertial sensor to provide globally-referenced centimeter-and-degree-accurate tracking of the VR headset. Unlike existing augmented and virtual reality systems, which perform camera-based inside-out headset tracking relative to a local reference frame (e.g., an ad-hoc frame fixed to a living room), OWVR's globally-referenced tracking enables a novel VR experience in which the user's outdoor exploration is robust to extremes in lighting conditions and local visual texture. This paper introduces the OWVR concept and presents a prototype OWVR system with two candidate sensor fusion architectures, one loosely and one tightly coupled. Comparative performance is evaluated in terms of tracking accuracy and availability of an integer-aperture-test-validated fixed tracking solution. For scenarios with degraded GNSS availability, which will be typical for outdoor VR, the tightly-coupled architecture is shown to offer a critical tracking robustness advantage.Aerospace Engineering and Engineering Mechanic
POTENTIAL BIRD REPELLENTS TO REDUCE BIRD DAMAGE TO LETTUCE SEED AND SEEDLINGS
The authors evaluated the effectiveness of ReJeX-iT® AG-145, Mesurol®, activated charcoal, lime, and fipronil to reduce homed lark damage to lettuce seeds and seedlings. In Experiment 1, homed larks consumed significantly more feed mixture (50:50 grains and lettuce seed) than untreated clay-coated lettuce seed in a three-day choice-test. In Experiment 2, where clay-coated lettuce seed was treated with ReJeX-iT® AG- 145, Mesurol®, activated charcoal, or lime, there was no significant difference in consumption of untreated clay-coated lettuce seed and treated clay-coated lettuce seed. Homed larks consumed insignificant amounts of all seed treatments including untreated coated lettuce seed. In this experiment homed larks lost an average of 28 % of their body weight over the three-day test period. It was concluded that the clay seed coating alone reduced damage significantly. In the aviary test, flats of sprouting lettuce seedlings were sprayed with Mesurol® (4 kg/ha), ReJeX-iT® AG-145 (64 kg/ha), lime (32 kg/ha), activated charcoal (32 kg/ha), and fipronil(4 kg/ha). Mesurol®, ReJeX-iT® AG-145, and lime significantly reduced consumption of lettuce seedlings over a four-day test period. Even though lime significantly reduced consumption, homed larks still consumed over 50% of the available lettuce seedlings. Field evaluations are warranted with Mesurol® and ReJeX-iT® AG-145
A modern coastal ocean observing system using data from advanced satellite and in situ sensors – an example
Report of the Ocean Observation Research Coordination Network In-situ-Satellite Observation Working GroupThis report is intended to illustrate and provide recommendations for how ocean observing
systems of the next decade could focus on coastal environments using combined
satellite and in situ measurements. Until recently, space-based observations have had surface
footprints typically spanning hundreds of meters to kilometers. These provide excellent synoptic
views for a wide variety of ocean characteristics. In situ observations are instead generally point
or linear measurements. The interrelation between space-based and in-situ observations can be
challenging. Both are necessary and as sensors and platforms evolve during the next decade, the
trend to facilitate interfacing space and in-situ observations must continue and be expanded. In
this report, we use coastal observation and analyses to illustrate an observing system concept that
combines in situ and satellite observing technologies with numerical models to quantify subseasonal
time scale transport of freshwater and its constituents from terrestrial water storage
bodies across and along continental shelves, as well as the impacts on some key
biological/biogeochemical properties of coastal waters.Ocean Research Coordination Network and the National Science Foundatio
CRISPR/Cas9 Genome Editing to Disable the Latent HIV-1 Provirus
HIV-1 infection can be successfully controlled with anti-retroviral therapy (ART), but is not cured. A reservoir of cells harboring transcriptionally silent integrated provirus is able to reestablish replicating infection if ART is stopped. Latently HIV-1 infected cells are rare, but may persist for decades. Several novel strategies have been proposed to reduce the latent reservoir, including DNA sequence targeted CRISPR/Cas9 genome editing of the HIV-1 provirus. A significant challenge to genome editing is the sequence diversity of HIV-1 quasispecies present in patients. The high level of quasispecies diversity will require targeting of multiple sites in the viral genome and personalized engineering of a CRISPR/Cas9 regimen. The challenges of CRISPR/Cas9 delivery to the rare latently infected cells and quasispecies sequence diversity suggest that effective genome editing of every provirus is unlikely. However, recent evidence from post-treatment controllers, patients with controlled HIV-1 viral burden following interruption of ART, suggests a correlation between a reduced number of intact proviral sequences and control of the virus. The possibility of reducing the intact proviral sequences in patients by a genome editing technology remains intriguing, but requires significant advances in delivery to infected cells and identification of effective target sites
Prospectus, September 26, 1985
https://spark.parkland.edu/prospectus_1985/1019/thumbnail.jp
Normal table of Xenopus development: a new graphical resource
© The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Zahn, N., James-Zorn, C., Ponferrada, V. G., Adams, D. S., Grzymkowski, J., Buchholz, D. R., Nascone-Yoder, N. M., Horb, M., Moody, S. A., Vize, P. D., & Zorn, A. M. Normal table of Xenopus development: a new graphical resource. Development, 149(14), (2022): dev200356, https://doi.org/10.1242/dev.200356.Normal tables of development are essential for studies of embryogenesis, serving as an important resource for model organisms, including the frog Xenopus laevis. Xenopus has long been used to study developmental and cell biology, and is an increasingly important model for human birth defects and disease, genomics, proteomics and toxicology. Scientists utilize Nieuwkoop and Faber's classic ‘Normal Table of Xenopus laevis (Daudin)’ and accompanying illustrations to enable experimental reproducibility and reuse the illustrations in new publications and teaching. However, it is no longer possible to obtain permission for these copyrighted illustrations. We present 133 new, high-quality illustrations of X. laevis development from fertilization to metamorphosis, with additional views that were not available in the original collection. All the images are available on Xenbase, the Xenopus knowledgebase (http://www.xenbase.org/entry/zahn.do), for download and reuse under an attributable, non-commercial creative commons license. Additionally, we have compiled a ‘Landmarks Table’ of key morphological features and marker gene expression that can be used to distinguish stages quickly and reliably (https://www.xenbase.org/entry/landmarks-table.do). This new open-access resource will facilitate Xenopus research and teaching in the decades to come.This work was supported by grants from the Eunice Kennedy Shriver National Institute of Child Health and Human Development [P41 HD064556 to A.M.Z. and P.D.V. (Xenbase)] and the National Institute of Child Health and Human Development [P40-OD010997 and R24-OD030008 to M.H. (National Xenopus Resource)]. Open Access funding provided by Cincinnati Children's Hospital Medical Center. Deposited in PMC for immediate release
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Transforming the study of organisms: Phenomic data models and knowledge bases
The rapidly decreasing cost of gene sequencing has resulted in a deluge of genomic data from across the tree of life; however, outside a few model organism databases, genomic data are limited in their scientific impact because they are not accompanied by computable phenomic data. The majority of phenomic data are contained in countless small, heterogeneous phenotypic data sets that are very difficult or impossible to integrate at scale because of variable formats, lack of digitization, and linguistic problems. One powerful solution is to represent phenotypic data using data models with precise, computable semantics, but adoption of semantic standards for representing phenotypic data has been slow, especially in biodiversity and ecology. Some phenotypic and trait data are available in a semantic language from knowledge bases, but these are often not interoperable. In this review, we will compare and contrast existing ontology and data models, focusing on nonhuman phenotypes and traits. We discuss barriers to integration of phenotypic data and make recommendations for developing an operationally useful, semantically interoperable phenotypic data ecosystem
Prospectus, December 4, 1985
https://spark.parkland.edu/prospectus_1985/1029/thumbnail.jp
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