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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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At least 253 records · Page 14
All sourcesNASA NTRSDOE OSTI
DOE OSTI2026

Will cities keep getting hotter? The interplay of urban expansion and greening reshapes future urban heat trajectories

Urban heat islands (UHIs) pose growing risks to public health, infrastructure, and resilience. While often assumed to intensify with urban growth, dynamic changes in urban expansion and vegetation greenness complicate UHI trajectories, which remain poorly understood. This study investigated the interplay of urban expansion and greenness change on UHI spatial profile across 36 Chinese megacities during 2003–2018 using multiple satellite products. We introduce a framework that classifies urban areas into four dynamic development pathways based on impervious surface area (ISA) and enhanced vegetation index (EVI) trends: urbanized-greening, urbanized-browning, urbanizing-greening (UingG), and urbanizing-browning (UingB). While most urbanized centers exhibited greening driven by targeted initiatives and urbanizing suburbs showed browning due to vegetation loss, about 30% urban areas showed the reverse pattern, revealing overlooked complexity in urban development. Urban expansion and browning strengthened UHI in suburban areas, whereas greening initiatives mitigated UHI in urban center and mitigated UHI enhancement in suburban areas. Slowed warming in urban centers together with accelerated warming in suburban areas flattened the temperature gradient between urban centers and suburbs. This dynamic expanded the spatial extent of elevated temperatures and reshaped the classic urban-to-rural UHI profile into a flatter form. In UingB areas, UHI intensification was jointly driven by increase in ISA, vegetation loss, and their interaction, while in UingG areas, EVI increases and a negative interaction together offset over half of the warming driven by urban expansion. These findings reveal that UHI evolution is not unidirectional but depends on localized urbanization and greening dynamics, offering pathways for strategic heat mitigation.

greening initiative↗
DOE OSTI2020

Comprehensive analyses of 723 transcriptomes enhance genetic and biological interpretations for complex traits in cattle

By uniformly analyzing 723 RNA-seq data from 91 tissues and cell types, we built a comprehensive gene atlas and studied tissue specificity of genes in cattle. We demonstrated that tissue-specific genes significantly reflected the tissue-relevant biology, showing distinct promoter methylation and evolution patterns (e.g., brain-specific genes evolve slowest, whereas testisspecific genes evolve fastest). Through integrative analyses of those tissue-specific genes with large-scale genome-wide association studies, we detected relevant tissues/cell types and candidate genes for 45 economically important traits in cattle, including blood/immune system (e.g., CCDC88C) for male fertility, brain (e.g., TRIM46 and RAB6A) for milk production, and multiple growth-related tissues (e.g., FGF6 and CCND2) for body conformation. We validated these findings by using epigenomic data across major somatic tissues and sperm. Collectively, our findings provided novel insights into the genetic and biological mechanisms underlying complex traits in cattle, and our transcriptome atlas can serve as a primary source for biological interpretation, functional validation, studies of adaptive evolution, and genomic improvement in livestock.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2026

Monte Carlo Event Generation with Continuous Normalizing Flows

We apply continuous normalizing flows trained with the flow matching method to the problem of phase-space sampling in Monte Carlo event generation for high-energy collider physics. Focusing on lepton-pair and top-quark pair production with multiple jets, the two computationally most expensive processes at the Large Hadron Collider, we train helicity-conditioned continuous normalizing flows to remap the random numbers used in matrix element evaluation. Compared to standard methods, we achieve unweighting efficiency improvements by factors of up to 184 and 25 for the two processes at their respective highest jet number, at the cost of an increased evaluation time. When combining the advantages of continuous normalizing flows with the fast evaluation times of coupling-layer-based flows, using the RegFlow approach, we find parton-level unweighted event generation walltime gains of about a factor of 10 at the highest jet numbers. These substantial gains highlight the promise of samplers based on machine learning for next-generation collider experiments.

Bothmann, Enrico [CERN; Gottingen U.] (ORCID:00000↗
DOE OSTI2020

Bose-Einstein condensation phenomenology in systems with repulsive interactions

The role of repulsive interactions in statistical systems of Bose particles is investigated. Three different phenomenological frameworks are considered: A mean-field model, an excluded volume model, and a model with a medium-dependent effective mass. All three models are tuned to yield similar equations of state, with only minor deviations from the ideal Bose gas at small chemical potentials. Our analysis indicates, however, that these models lead to qualitatively different results for the Bose-Einstein condensation phenomenon. We discuss the different aspects of this phenomenon, namely, an onset of the Bose-Einstein condensation, particle number fluctuations, and a behavior of the Bose condensate. The obtained results can be helpful for interpreting the lattice QCD data at small temperature and large isospin chemical potential and the data on multiple pion production in high-energy nuclear collisions.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2016

Transverse energy production and charged-particle multiplicity at midrapidity in various systems from s N N = 7.7 to 200 GeV

Measurements of midrapidity charged-particle multiplicity distributions, dN ch /dη, and midrapidity transverse-energy distributions, dE T /dη, are presented for a variety of collision systems and energies. Included are distributions for Au+Au collisions at √s NN =200, 130, 62.4, 39, 27, 19.6, 14.5, and 7.7 GeV, Cu+Cu collisions at √s NN =200 and 62.4 GeV, Cu+Au collisions at √s NN =200 GeV, U+U collisions at√s NN =193 GeV, d+Au collisions at √s NN =200 GeV, He3+Au collisions at √s NN =200 GeV, and p+p collisions at √s NN =200 GeV. We present centrality-dependent distributions at midrapidity in terms of the number of nucleon participants, N part , and the number of constituent quark participants, N qp . For all A+A collisions down to √s NN =7.7 GeV, we observed that the midrapidity data are better described by scaling with N qp than scaling with N part . Finally, our estimates of the Bjorken energy density, ε BJ , and the ratio of dE T /dη to dN ch /dη are presented, the latter of which is seen to be constant as a function of centrality for all systems.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2015

Effective field theory analysis of Higgs naturalness

Assuming the presence of physics beyond the Standard Model ( SM) with a characteristic scale M ~ O (10) TeV, we investigate the naturalness of the Higgs sector at scales below M using an effective field theory (EFT) approach. We obtain the leading 1 -loop EFT contributions to the Higgs mass with a Wilsonian-like hard cutoff, and determine t he constraints on the corresponding operator coefficients for these effects to alleviate the little hierarchy problem up to the scale of the effective action Λ < M , a condition we denote by “EFT-naturalness”. We also determine the types of physics that can lead to EFT-naturalness and show that these types of new physics are best probed in vector-boson and multiple-Higgs production. The current experimental constraints on these coefficients are also discussed.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2019

Dispersal behaviour of Euwallacea nr. fornicatus (Coleoptera: Curculionidae: Scolytinae) in avocado groves and estimation of lure sampling range

Abstract Invasive ambrosia beetles in the Euwallacea nr. fornicatus species complex (Coleoptera: Curculionidae: Scolytinae) threaten avocado production in multiple countries. These pests are currently monitored with lures containing quercivorol; α‐copaene was also recently discovered to be an effective attractant. We investigated dispersal behaviour of female E . nr . fornicatus in two Florida avocado groves using mark–release–recapture experiments and laboratory flight mills. Additionally, we estimated the sampling range of quercivorol and α‐copaene lures deployed alone and in tandem. The two‐component lure recaptured 31.2% of marked beetles, which was significantly more than quercivorol (11.2%) or α‐copaene (8.8%) alone. Contour analysis indicated that wind speed and direction can influence the number of females that disperse, as well as the direction and distance of their flight. Two methods were used to estimate sampling range and both of them indicated comparable effective ranges for the three lure treatments, with 80% of marked beetles being recaptured within 30–35 m of the release point. Average total flight distance in laboratory tests was 81.0 m in 24 h, with a maximum distance recorded at 400 m. The combination of quercivorol and α‐copaene lures provides the best detection of pest E . nr. fornicatus in Florida, with a recommended trap spacing of approximately 30 m in surveillance programmes for this pest in avocado groves.

Owens, David↗
DOE OSTI2018

Resilience of seed production to a severe El Niño-induced drought across functional groups and dispersal types

More frequent and severe El Niño Southern Oscillations (ENSO) are causing episodic periods of decreased rainfall. Although the effects of these ENSO-induced droughts on tree growth and mortality have been well studied, the impacts on other demographic rates such as reproduction are less well known. We use a four-year seed rain dataset encompassing the most severe ENSO-induced drought in more than 30 years to assess the resilience (i.e., resistance and recovery) of the seed composition and abundance of three forest types in a tropical dry forest. We found that forest types showed distinct differences in the timing, duration, and intensity of drought during the ENSO event, which likely mediated seed composition shifts and resilience. Drought-deciduous species were particularly sensitive to the drought with overall poor resilience of seed production, whereby seed abundance of this functional group failed to recover to predrought levels even two years after the drought. Liana and wind-dispersed species were able to maintain seed production both during and after drought, suggesting that ENSO events promote early successional species or species with a colonization strategy. Combined, these results suggest that ENSO-induced drought mediates the establishment of functional groups and dispersal types suited for early successional conditions with more open canopies and reduced competition among plants. Finally, the effects of the ENSO-induced drought on seed composition and abundance were still evident two years after the event suggesting the recovery of seed production requires multiple years that may lead to shifts in forest composition and structure in the long term, with potential consequences for higher trophic levels like frugivores.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2017

Inflammatory monocytes expressing tissue factor drive SIV and HIV coagulopathy

In HIV infection, persistent inflammation despite effective antiretroviral therapy is linked to increased risk of noninfectious chronic complications such as cardiovascular and thromboembolic disease. Thus, a better understanding of inflammatory and coagulation pathways in HIV infection is needed to optimize clinical care. Markers of monocyte activation and coagulation independently predict morbidity and mortality associated with non-AIDS events. We identified a specific subset of monocytes that express tissue factor (TF), persist after virological suppression, and trigger the coagulation cascade by activating factor X. This subset of monocytes expressing TF had a distinct gene signature with up-regulated innate immune markers and evidence of robust production of multiple proinflammatory cytokines, including interleukin-1β (IL-1β), tumor necrosis factor–α (TNF-α), and IL-6, ex vivo and in vitro upon lipopolysaccharide stimulation. We validated our findings in a nonhuman primate model, showing that TF-expressing inflammatory monocytes were associated with simian immunodeficiency virus (SIV)–related coagulopathy in the progressive [pigtail macaques (PTMs)] but not in the nonpathogenic (African green monkeys) SIV infection model. Last, Ixolaris, an anticoagulant that inhibits the TF pathway, was tested and potently blocked functional TF activity in vitro in HIV and SIV infection without affecting monocyte responses to Toll-like receptor stimulation. Strikingly, in vivo treatment of SIV-infected PTMs with Ixolaris was associated with significant decreases in D-dimer and immune activation. These data suggest that TF-expressing monocytes are at the epicenter of inflammation and coagulation in chronic HIV and SIV infection and may represent a potential therapeutic target.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2015

Relative yield of heavy hadrons as a function of the transverse momentum in LHC experiments

The relative yield of hadrons involving a b quark (B{sub c}, B{sub s}, B, Ʌ{sub b}, etc.) is studied as a function of the transverse momentum. It is shown that the yields in question exhibit a nontrivial transverse-momentum dependence because of the difference in nonperturbative fragmentation functions and because of the contribution of power-law corrections at low transverse momenta.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2015

Study of the CP-violating effects with gg → Η → τ{sup +}τ{sup –} process

Study of the gg → Η → τ{sup +}τ{sup –} process was performed at Monte Carlo level within the framework of searching for CP-violating effects. The sensitivity of chosen observables to CP-parity of the Higgs boson was demonstrated for hadronic 1-prong τ decays (τ{sup ±} → π{sup ±}, ρ{sup ±}). Monte Carlo samples for the gg → Η → τ{sup +}τ{sup -} process were generated including the parton hadronisation to final state particles. This generation was performed for the Standard Model Higgs boson, the pseudoscalar Higgs boson, the Z → τ{sup +}τ{sup –} background, and mixed CP-states of the Higgs boson.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2015

Feasibility of flow studies at NICA/MPD

In the light of recent developments in heavy ion physic, anisotropic flow measurements play a key role in a better understanding of the hot and dense barionic matter. In the presented article a short introduction to the proposed NICA/MPD project is given, as well as a brief description of the event-plane method used to estimate the elliptic flow of reconstructed and identified hadrons (p, π, Λ)

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2019

Charged-particle production as a function of multiplicity and transverse spherocity in pp collisions at $ \sqrt{s}$ = 5.02 and 13 TeV

Here, we present a study of the inclusive charged-particle transverse momentum ( p T ) spectra as a function of charged-particle multiplicity density at mid-pseudorapidity, d N ch /dη, in pp collisions at $ \sqrt{s}$ = 5.02 and 13 TeV covering the kinematic range |η| < 0.8 and 0.15 < p T < 20 GeV/ c . The results are presented for events with at least one charged particle in |η| < 1 (INEL>0). The p T spectra are reported for two multiplicity estimators covering different pseudorapidity regions. The p T spectra normalized to that for INEL>0 show little energy dependence. Moreover, the high- p T yields of charged particles increase faster than the charged-particle multiplicity density. The average p T as a function of multiplicity and transverse spherocity is reported for pp collisions at $ \sqrt{s}$=13 TeV. For low- (high-) spherocity events, corresponding to jet-like (isotropic) events, the average p T is higher (smaller) than that measured in INEL>0 pp collisions. Within uncertainties, the functional form of &lang; p T &rang; ( N ch ) is not affected by the spherocity selection. While EPOS LHC gives a good description of many features of data, PYTHIA overestimates the average p T in jet-like events.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2018

Drivers of the Low-Cloud Response to Poleward Jet Shifts in the North Pacific in Observations and Models

The long-standing expectation that poleward shifts of the midlatitude jet under global warming will lead to poleward shifts of clouds and a positive radiative feedback on the climate system has been shown to be misguided by several recent studies. On interannual time scales, free-tropospheric clouds are observed to shift along with the jet, but low clouds increase across a broad expanse of the North Pacific Ocean basin, resulting in negligible changes in total cloud fraction and top-of-atmosphere radiation. Here it is shown that this low-cloud response is consistent across eight independent satellite-derived cloud products. Using multiple linear regression, it is demonstrated that the spatial pattern and magnitude of the low-cloud-coverage response is primarily driven by anomalous surface temperature advection. In the eastern North Pacific, anomalous cold advection by anomalous northerly surface winds enhances sensible and latent heat fluxes from the ocean into the boundary layer, resulting in large increases in low-cloud coverage. Local increases in low-level stability make a smaller contribution to this low-cloud increase. Despite closely capturing the observed response of large-scale meteorology to jet shifts, global climate models largely fail to capture the observed response of clouds and radiation to interannual jet shifts because they systematically underestimate how sensitive low clouds are to surface temperature advection, and to a lesser extent, low-level stability. More realistic model simulations of cloud–radiation–jet interactions require that parameterizations more accurately capture the sensitivity of low clouds to surface temperature advection.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2024

UMap: An application-oriented user level memory mapping library

Exploiting the prominent role of complex memories in exascale node architecture, the UMap page fault handler offers new capabilities to access large memory-mapped data sets directly. UMap provides flexible configuration options to customize page handling to each application, including analysis of massive observational and simulation data sets. The high-performance design features I/O decoupling, dynamic load balancing, and application-level controls. Page faults triggered by application threads and processes accessing data mapped to a UMapp’ed region are handled via the Linux userfaultfd protocol, an asynchronous message-oriented kernel-user communication mechanism that avoids the context switch penalty of traditional signal fault handlers. UMap is fully open source. In this paper, we give an overview of the UMap library architecture, its extensible plugin architecture, and the use/performance of UMap in emerging heterogeneous memory hierarchies such as near-node Non-volatile Memory (NVM) and network attached memories. We highlight new capabilities in two pagefault management plugins, the NetworkStore and SparseStore. We demonstrate the integration between UMap and multiple ECP products including Caliper, Metall, ZFP, Mochi, and Ripples.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2019

Variable genome evolution in fungi after transposon-mediated amplification of a housekeeping gene

Transposable elements (TEs) can be key drivers of evolution, but the mechanisms and scope of how they impact gene and genome function are largely unknown. Previous analyses revealed that TE-mediated gene amplifications can have variable effects on fungal genomes, from inactivation of function to production of multiple active copies. For example, a DNA methyltransferase gene in the wheat pathogen Zymoseptoria tritici (synonym Mycosphaerella graminicola) was amplified to tens of copies, all of which were inactivated by Repeat-Induced Point mutation (RIP) including the original, resulting in loss of cytosine methylation. In another wheat pathogen, Pyrenophora tritici-repentis, a histone H3 gene was amplified to tens of copies with little evidence of RIP, leading to many potentially active copies. To further test the effects of transposon-aided gene amplifications on genome evolution and architecture, the repetitive fraction of the significantly expanded genome of the banana pathogen, Pseudocercospora fijiensis, was analyzed in greater detail. These analyses identified a housekeeping gene, histone H3, which was captured and amplified to hundreds of copies by a hAT DNA transposon, all of which were inactivated by RIP, except for the original. In P. fijiensis the original H3 gene probably was not protected from RIP, but most likely was maintained intact due to strong purifying selection. Comparative analyses revealed that a similar event occurred in five additional genomes representing the fungal genera Cercospora, Pseudocercospora and Sphaerulina. These results indicate that the interplay of TEs and RIP can result in different and unpredictable fates of amplified genes, with variable effects on gene and genome evolution.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2015

Nuclear Hybrid Energy Systems - Regional Studies. West Texas and Northeastern Arizona

The primary objective of this study is to conduct a preliminary dynamic analysis of two realistic hybrid energy systems (HES) including a nuclear reactor as the main baseload heat generator (denoted as nuclear HES or nuclear hybrid energy systems [NHES]) and to assess the local (e.g., HES owners) and system (e.g., the electric grid) benefits attainable by the application of NHES in scenarios with multiple commodity production and high penetration of renewable energy. It is performed for regional cases - not generic examples - based on available resources, existing infrastructure, and markets within the selected regions. This study also briefly addresses the computational capabilities developed to conduct such analyses, reviews technical gaps, and suggests some research paths forward.

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗