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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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Identification of Low-Abundance Lipid Droplet Proteins in Seeds and Seedlings
Not provided.
IncProf: Efficient Source-Oriented Phase Identification for Application Behavior Understanding.
Abstract not provided.
Object composition identification via mediated-reality supplemented radiographs.
Abstract not provided.
N-k Failure Analysis Algorithm for Identification of Extreme Events for Cascading Outage Pre-screening process
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Identification of Intraday False Data Injection Attack on DER Dispatch Signals
The urgent need for the decarbonization of power grids has accelerated the integration of renewable energy. Concurrently, increasing distributed energy resources (DER) and advanced metering infrastructure (AMI) have transformed the power grids into a more sophisticated cyber-physical system with numerous communication devices. While these transitions provide economic and environmental value, they also impose increased risk of cyber attacks and operation al challenges. This paper investigates the vulnerabilit y of the power grids with high renewable penetration against an intraday false data injection (FDI) attack on DER dispatch signals and proposes a kernel support vector regression (SVR) based detection model as a countermeasure. The intraday FDI attack scenario and the detection model are demonstrated in a numerical experiment using the HCE 187-bus test system.
The Miller Range 090340 and 090206 meteorites: Identification of new brachinite-like achondrites with implications for the diversity and petrogenesis of the brachinite clan
Miller Range (MIL) 090340 and MIL 090206 are olivine-rich achondrites originally classified as ureilites. We investigate their petrography, mineral compositions, olivine Cr valences, equilibration temperatures, and (for MIL 090340) oxygen isotope compositions, and compare them with ureilites and other olivine-rich achondrites. We conclude that they are brachinite-like achondrites that provide new insights into the petrogenesis of brachinite clan meteorites. MIL 090340,6 has a granoblastic texture and consists of ~97 modal % by area olivine (Fo = molar Mg/[Mg+Fe] = 71.3 ± 0.6). It also contains minor to trace augite, chromite, chlorapatite, orthopyroxene, metal, troilite, and terrestrial Fe-oxides. Approximately 80% by area of MIL 090206,5 has a granoblastic texture of olivine (Fo 72.3 ± 0.1) plus minor augite and chromite, similar to MIL 090340 but also containing minor plagioclase. The rest of the section consists of a single crystal of orthopyroxene (~11 × 3 mm), poikilitically enclosing rounded grains of olivine (Fo = 76.1 ± 0.6), augite, chromite, metal, and sulfide. Equilibration temperatures for MIL 090340 and MIL 090206, calculated from olivine-spinel, olivine-augite, and two-pyroxene thermometry range from ~800 to 930 °C. In both samples, symplectic intergrowths of Ca-poor orthopyroxene + opaque phases (Fe-oxides, sulfide, metal) occur as rims on and veins/patches within olivine. Before terrestrial weathering, the opaques were probably mostly sulfide, with minor metal. All petrologic properties of MIL 090340 and MIL 090206 are consistent with those of brachinite clan meteorites, and largely distinct from those of ureilites. Oxygen isotope compositions of olivine in MIL 090340 (δ 18 O = 5.08 ± 0.30‰, δ 17 O = 2.44 ± 0.21‰, and Δ 17 O = -0.20 ± 0.12‰) are also within the range of brachinite clan meteorites, and well distinguished from ureilites. Olivine Cr valences in MIL 090340 and the granoblastic area of MIL 090206 are 2.57 ± 0.06 and 2.59 ± 0.07, respectively, similar to those of three brachinites also analyzed here (Brachina, Hughes 026, Nova 003). They are higher than those of olivine in ureilites, even those containing chromite. The valence systematics of MIL 090340, MIL 090206, and the three analyzed brachinites (lower Fo = more oxidized Cr) are consistent with previous evidence that brachinite-like parent bodies were inherently more oxidized than the ureilite parent body. The symplectic orthopyroxene + sulfide/metal assemblages in MIL 090340, MIL 090206, and many brachinite clan meteorites have superficial similarities to characteristic “reduction rims” in ureilites. However, they differ significantly in detail. They likely formed by reaction of olivine with S-rich fluids, with only minor reduction. MIL 090340 and the granoblastic area of MIL 090206 are similar in modal mineralogy and texture to most brachinites, but have higher Fo values typical of brachinite-like achondrites. The poikilitic pyroxene area of MIL 090206 is more typical of brachinite-like achondrites. The majority of their properties suggest that MIL 090340 and MIL 090206 are residues of low-degree partial melting. The poikilitic area of MIL 090206 could be a result of limited melt migration, with trapping and recrystallization of a small volume of melt in the residual matrix. Finally, these two samples are so similar in mineral compositions, Cr valence, and cosmic ray exposure ages that they could be derived from the same lithologic unit on a common parent body.
Identification and Overexpression of Gibberellin 2-Oxidase (GA2ox) in Switchgrass (Panicum virgatum L.) for Improved Plant Architecture and Reduced Biomass Recalcitrance
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Identification of Fragments in a Meshfree Peridynamic Simulation.
Abstract not provided.
Identification of the I38T PA Substitution as a Resistance Marker for Next-Generation Influenza Virus Endonuclease Inhibitors
ABSTRACT The clinical severity and annual occurrence of influenza virus epidemics, combined with the availability of just a single class of antivirals to treat infections, underscores the urgent need to develop new anti-influenza drugs. The endonuclease activity within the viral acidic polymerase (PA) protein is an attractive target for drug discovery due to the critical role it plays in viral gene transcription. RO-7 is a next-generation PA endonuclease inhibitor of influenza A and B viruses, but its drug resistance potential is unknown. Through serial passage of influenza A(H1N1) viruses in MDCK cells under selective pressure of RO-7, we identified an I38T substitution within the PA endonuclease domain that conferred in vitro resistance to RO-7 (up to a 287-fold change in 50% effective concentration [EC 50 ]). I38T emerged between 5 and 10 passages, and when introduced into recombinant influenza A(H1N1) viruses, alone conferred RO-7 resistance (up to an 81-fold change in EC 50 ). Cocrystal structures of mutant and wild-type endonuclease domains with RO-7 provided the structural basis of resistance, where a key hydrophobic interaction between RO-7 and the Ile38 side chain is compromised when mutated to the polar threonine. While Ile38 does not have a crucial role in coordinating the endonuclease active site, the switch to threonine does affect the polymerase activity of some viruses and influences RO-7 affinity for the PA N target (i.e., the ≈200-residue N-terminal domain of PA). However, the change does not lead to a complete loss of replication activity in vitro . Our results predict that RO-7-resistant influenza viruses carrying the I38T substitution may emerge under treatment. This should be taken into consideration for clinical surveillance and in refinement of these drugs. IMPORTANCE The effectiveness of antiviral drugs can be severely compromised by the emergence of resistant viruses. Therefore, determination of the mechanisms by which viruses become resistant is critical for drug development and clinical use. RO-7 is a compound that potently inhibits influenza virus replication and belongs to a new class of drugs in late-stage clinical trials for treatment of influenza virus infection. Here we demonstrate that a single amino acid change acquired under prolonged virus exposure to RO-7 renders influenza viruses significantly less susceptible to its inhibitory effects. We have discovered how the mutation can simultaneously interfere with drug activity and still maintain efficient virus replication. These findings have important implications for the development of more effective derivatives of RO-7-like drugs and provide guidance for how to monitor the emergence of resistance.
Identification of boosted, hadronically decaying W bosons and comparisons with ATLAS data taken at root s=8 TeV
N/A
Identification of boosted Higgs bosons decaying into b -quark pairs with the ATLAS detector at 13 TeV
This study describes a study of techniques for identifying Higgs bosons at high transverse momenta decaying into bottom-quark pairs, $H → b\bar{b}$, for proton–proton collision data collected by the ATLAS detector at the Large Hadron Collider at a centre-of-mass energy $\sqrt{\bar{s}}$ = 13 TeV. These decays are reconstructed from calorimeter jets found with the anti-$k_t R$ = 1.0 jet algorithm. To tag Higgs bosons, a combination of requirements is used: b -tagging of $R$ = 0.2 track-jets matched to the large- R calorimeter jet, and requirements on the jet mass and other jet substructure variables. The Higgs boson tagging efficiency and corresponding multijet and hadronic top-quark background rejections are evaluated using Monte Carlo simulation. Several benchmark tagging selections are defined for different signal efficiency targets. The modelling of the relevant input distributions used to tag Higgs bosons is studied in 36 fb -1 of data collected in 2015 and 2016 using $g → b\bar{b}$ and $Z(→ b\bar{b})γ$ event selections in data. Both processes are found to be well modelled within the statistical and systematic uncertainties.
Identification and Characterization of Persistent Cold Pool Events from Temperature and Wind Profilers in the Columbia River Basin
Cold pool events occur when deep layers of stable, cold air remain trapped in a valley or basin for multiple days, without mixing out from daytime heating. With large impacts on air quality, freezing events, and es-pecially on wind energy production, they are often poorly forecast by modern mesoscale numerical weather prediction (NWP) models. Understanding the characteristics of cold pools is, therefore, important to provide more accurate forecasts. This study analyzes cold pool characteristics with data collected during the Second Wind Forecast Improvement Project (WFIP2), which took place in the Columbia River basin and Gorge of Oregon and Washington from fall 2015 until spring 2017. A subset of the instrumentation included three microwave radiometer pro?lers, six radar wind pro?lers with radio acoustic sounding systems, and seven sodars, which together provided seven sites with collocated vertical pro?les of temperature, humidity, wind speed, and wind direction. Using these collocated observations, we developed a set of criteria to determine if a cold pool was present based on stability, wind speed, direction, and temporal continuity, and then developed an automated algorithm based on these criteria to identify all cold pool events over the 18 months of the ?eld project. Characteristics of these events are described, including statistics of the wind speed distributions and pro?les, stability conditions, cold pool depths, and descent rates of the cold pool top. The goal of this study is a better understanding of these characteristics and their processes to ultimately lead to improved physical parameterizations in NWP models, and consequently improve forecasts of cold pool events in the study region as well at other locations that experiences similar events.
Identification of the core set of carbon-associated genes in a bioenergy grassland soil
Despite the central role of soil microbial communities in global carbon (C) cycling, little is known about soil microbial community structure and even less about their metabolic pathways. Efforts to characterize soil communities often focus on identifying differences in gene content across environmental gradients, but an alternative question is what genes are similar in soils. These genes may indicate critical species or potential functions that are required in all soils. Here we identified the “core” set of C cycling sequences widely present in multiple soil metagenomes from a fertilized prairie (FP). Of 226,887 sequences associated with known enzymes involved in the synthesis, metabolism, and transport of carbohydrates, 843 were identified to be consistently prevalent across four replicate soil metagenomes. This core metagenome was functionally and taxonomically diverse, representing five enzyme classes and 99 enzyme families within the CAZy database. Though it only comprised 0.4% of all CAZy-associated genes identified in FP metagenomes, the core was found to be comprised of functions similar to those within cumulative soils. The FP CAZy-associated core sequences were present in multiple publicly available soil metagenomes and most similar to soils sharing geographic proximity. In soil ecosystems, where high diversity remains a key challenge for metagenomic investigations, these core genes represent a subset of critical functions necessary for carbohydrate metabolism, which can be targeted to evaluate important C fluxes in these and other similar soils.
Identification of a classical mutant in the industrial host Aspergillus niger by systems genetics: LaeA is required for citric acid production and regulates the formation of some secondary metabolites
Rapid acidification of the culture medium by the production of organic acids and the production of acid-induced proteases are key characteristics of the filamentous fungus Aspergillus niger. The D15 mutant of A. niger is non-acidifying mutant and used often for the expression of recombinant proteins in A. niger, because of its reduced production of extracellular proteases under non-acidic conditions. In this study, the D15 mutant is characterized in detail. Strongly reduced levels of citric and oxalic acid were observed in the D15 mutant both in shake flask cultures and in controlled batch cultivations. To identify the mutation in the D15 mutant, we successfully combined high-throughput sequencing (Illumina) with bulk segregant analysis. Because of the lack of a sexual cycle for A. niger, the parasexual cycle was used to generate a pool of segregants. From the 52 single nucleotide polymorphisms (SNPs) between the parental strains, three SNPs were homozygous in the genomic DNA of pool of segregants. These three SNPs mapped to all the right arm of chromosome II, indicating that this region contains the genetic locus affecting the phenotype related to acid production. Of the three SNPs, one mutation resulted in a missense mutation in the gene encoding the A. niger homologue of the A. nidulans methyltransferase gene laeA. Complementation analysis of the original mutant with the laeA gene and targeted disruption of laeA further confirmed that LaeA is involved in citric acid production in A. niger lab (N402) and citric acid production strains (ATCC 11414). Analysis of the secondary metabolite (SM) profile of the laeA mutants indicate that LaeA is required for the production of several SMs (asperrubrol, atromentin and JBIR86), but deletion of laeA also resulted in the presence of SMs (aspernigrin A/B and BMS-192548) that were not detected in the wild-type strain. The levels of ten other SMs were not strongly affected as a result of laeA deletion indicating that only a limited number of SM gene clusters are controlled by LaeA activity.
Wind Turbine Wake Definition and Identification using Velocity Deficit and Turbulence Profile.
Abstract not provided.
Identification of Accretion as Grain Growth Mechanism in Astrophysically Relevant Water–Ice Dusty Plasma Experiment
The grain growth process in the Caltech water–ice dusty plasma experiment has been studied using a high-speed camera and a long-distance microscope lens. It is observed that (i) the ice grain number density decreases fourfold as the average grain major axis increases from 20 to 80 μ m, (ii) the major axis length has a log-normal distribution rather than a power-law dependence, and (iii) no collisions between ice grains are apparent. The grains have a large negative charge resulting in strong mutual repulsion and this, combined with the fractal character of the ice grains, prevents them from agglomerating. In order for the grain kinetic energy to be sufficiently small to prevent collisions between ice grains, the volumetric packing factor (i.e., ratio of the actual volume to the volume of a circumscribing ellipsoid) of the ice grains must be less than ∼0.1 depending on the exact relative velocity of the grains in question. Thus, it is concluded that direct accretion of water molecules is very likely to dominate the observed ice grain growth.