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DOE OSTI2024

Storm surges and extreme sea levels: Review, establishment of model intercomparison and coordination of surge climate projection efforts (SurgeMIP).

Coastal flood damage is primarily the result of extreme sea levels. Climate change is expected to drive an increase in these extremes. While proper estimation of changes in storm surges is essential to estimate changes in extreme sea levels, there remains low confidence in future trends of surge contribution to extreme sea levels. Alerting local populations of imminent extreme sea levels is also critical to protecting coastal populations. Both predicting and projecting extreme sea levels require reliable numerical prediction systems. The SurgeMIP (surge model intercomparison) community has been established to tackle such challenges. Efforts to intercompare storm surge prediction systems and coordinate the community 's prediction and projection efforts are introduced. An overview of past and recent advances in storm surge science such as physical processes to consider and the recent development of global forecasting systems are briefly introduced. Selected historical events and drivers behind fast increasing service and knowledge requirements for emergency response to adaptation considerations are also discussed. The community 's initial plans and recent progress are introduced. These include the establishment of an intercomparison project, the identification of research and development gaps, and the introduction of efforts to coordinate projections that span multiple climate scenarios.

54 ENVIRONMENTAL SCIENCES↗

DOE OSTI2024

PRISTINE: An Emulation Platform for PCB-Level Hardware Trojans

Printed circuit Boards (PCBs) are becoming increasingly vulnerable to malicious design alteration, also known as Trojan attacks, due to a distributed business model that often involves various untrusted parties. Such attacks can be mounted at various stages in the PCB life cycle. The relative ease of alteration of PCB hardware even after fabrication (due to physical access to surface-mounted critical components and traces) makes them attractive for an adversary to manipulate their functional/physical behavior for malicious intent. There is a growing need to explore viable Trojan attacks in a PCB, analyze their functional and physical characteristics (e.g., impact on power or delay), and study the effectiveness of countermeasures against these attacks. While simulation-based approaches for PCB Trojan insertion are effective at creating a large population of possible Trojans, they fail to provide functional feasibility analysis with a realistic workload for a trigger circuit. Also, they cannot estimate a Trojan’s side-channel footprint due to the unavailability of physical models of diverse PCB components. To address these deficiencies, in this paper, we present PRISTINE, a PCB-level emulation system for any integrity or physical tampering issues, specifically, hardware Trojan insertion. The need for building such an emulation platform to resolve PCB trust issues in the supply chain is also surveyed and discussed. Both custom Hardware Hacking (HaHa) boards and multiple commercial PCBs are then used to test the ability of the proposed system to emulate various hardware Trojans specially designed to exploit board-specific hardware characteristics. Experimental results on emulated board-level Trojans show that a wide range of Trojans can be successfully activated, thus enabling the expected payload effects on both types of boards to be studied and quantified. The resulting data are further analyzed to create PCB-level Trojan benchmarks. In particular, a comparative evaluation of the experimental results is used to propose a risk level metric that quantifies the probability of detection and degree of payload impact of each Trojan on a given commercial PCB.

47 OTHER INSTRUMENTATION↗

DOE OSTI2020

Using Low-Cost Measurement Systems to Investigate Air Quality: A Case Study in Palapye, Botswana

Exposure to particulate air pollution is a major cause of mortality and morbidity worldwide. In developing countries, the combustion of solid fuels is widely used as a source of energy, and this process can produce exposure to harmful levels of particulate matter with diameters smaller than 2.5 microns (PM 2.5 ). However, as countries develop, solid fuel may be replaced by centralized coal combustion, and vehicles burning diesel and gasoline may become common, changing the concentration and composition of PM 2.5 , which ultimately changes the population health effects. Therefore, there is a continuous need for in-situ monitoring of air pollution in developing nations, both to estimate human exposure and to monitor changes in air quality. In this study, we present measurements from a 5-week field experiment in Palapye, Botswana. We used a low-cost, highly portable instrument package to measure surface-based aerosol optical depth (AOD), real-time surface PM 2.5 concentrations using a third-party optical sensor, and time-integrated PM 2.5 concentration and composition by collecting PM 2.5 onto Teflon filters. Furthermore, we employed other low-cost measurements of real-time black carbon and time-integrated ammonia to help interpret the observed PM 2.5 composition and concentration information during the field experiment. We found that the average PM 2.5 concentration (9.5 μg∙m –3 ) was below the World Health Organization (WHO) annual limit, and this concentration closely agrees with estimates from the Global Burden of Disease (GBD) report estimates for this region. Sulfate aerosol and carbonaceous aerosol, likely from coal combustion and biomass burning, respectively, were the main contributors to PM 2.5 by mass (33% and 27% of total PM 2.5 mass, respectively). While these observed concentrations were on average below WHO guidelines, we found that the measurement site experienced higher concentrations of aerosol during first half our measurement period (14.5 μg∙m –3 ), which is classified as "moderately unhealthy" according to the WHO standard.

54 ENVIRONMENTAL SCIENCES↗

NASA NTRS1976

White dwarfs, the Galaxy and Dirac's cosmology

The additive and multiplicative versions of Dirac's cosmological hypothesis relating the gravitational constant variation with elapsed time and number of particles populating the universe is invoked to account for the deficiency or absence of white dwarfs fainter than about 0.0001 solar luminosity. An estimate is made of white dwarf luminosity in accordance with the two evolutionary models, and it is conjectured that some old white dwarfs with high space velocities may be on the verge of gravitational collapse. Lack of a special mechanism to produce the vast numbers of black holes or other dead stars accounting for 'missing matter' in the vicinity of the sun and in the galactic halo is noted in Dirac's multiplicative model. Results indicate that either Dirac's theory is untenable, or that radiation and heating are of some unknown nature, or that the process of creation of new matter requires a corresponding input of energy.

Stothers, R.↗

NASA NTRS1990

Possible deficiency of large Martian craters and relative cratering of the terrestrial planets

Mars appears to be deficient in large craters relative to Mercury and the Moon. This relative deficiency conflicts with the interpretation of a common population of impactors within the early inner solar system and suggest either of two possibilities. If the apparent deficiency of martian craters is real then the population of impactors at Mars differed significantly from that closer to the Sun. If the apparent deficiency is not real then the complete crater inventory of Mars should be similar to those of Mercury and the Moon, supporting the interpretation of a single population of impactors. These alternate possibilities can be tested by comparing revised inventories that include partly buried or eroded craters to an estimate of Mars' possible relative crater deficiency.

Schultz, Richard A.↗

NASA NTRS2003

UV Spectral Templates for High-Redshift Galaxies

New instrumentation such as DEIMOS on Keck-II now enable deep spectral surveys, and thereby samples of galaxies at younger ages. At a redshift, z = 1, all galaxies are less than 6 Gyr old and hence, have not yet formed horizontal-branch stars. Also, at z = 1, the restframe-UV comes into view, and with it, a new set of spectral diagnostics. UV spectral features are especially important because most of the UV flux comes from stars at the main-sequence turnoff (MSTO). Hence, UV spectral diagnostics enable the ages of z = 1 galaxies to be estimated directly from MSTO stars. In preparation for these high-redshift spectral surveys, we are developing UV spectral templates for stellar populations younger than 6 Gyr using UV-optical spectra of stars observed by HST/STIS. We are also planning to supplement these observations with theoretical spectral grids of stars of various metallicities. In this paper, we present a progress report on the observation-based spectral templates and spectral diagnostics.

Heap, Sara↗

NASA NTRS2003

UV Spectral Diagnostics of Galaxy Evolution

New instrumentation now enable deep spectral surveys of galaxies at younger ages. At a redshift, z=1, all galaxies are less than 6 Gyr old and hence, have not yet formed horizontal-branch stars. Also, at z=1, the restframe-UV comes into view, and with it, a new set of spectral diagnostics. UV spectral features are especially important because most of the UV flux comes from stars at the main-sequence turnoff (MSTO). Hence, UV spectral diagnostics enable the most recent star formation episode of high-redshift galaxies to be estimated directly from MSTO stars. In preparation for these high-redshift spectral surveys, we are developing UV spectral templates for stellar populations younger than 6 Gyr using UV-optical spectra of stars observed by HST/STIS. We are also starting to supplement these observations with theoretical spectral grids of stars of various metallicities. In this paper, we present a progress report on UV spectral templates and spectral diagnostics.

Heap, Sara R.↗

NASA NTRS2003

UV Spectral Diagnostics

New instrumentation now enable deep spectral surveys of galaxies at younger ages. At a redshift, z=l, all galaxies are less than 6 Gyr old and hence, have not yet formed horizontal-branch stars. Also, at z=1, the restframe-UV comes into view, and with it, a new set of spectral diagnostics. UV spectral features are especially important because most of the UV flux comes from stars at the main-sequence turnoff (MSTO). Hence, UV spectral diagnostics enable the most recent star formation episode of high-redshift galaxies to be estimated directly from MSTO stars. In preparation for these high-redshift spectral surveys, we are developing UV spectral templates for stellar populations younger than 6 Gyr using UV-optical spectra of stars observed by HST/STIS. We are also starting to supplement these observations with theoretical spectral grids of stars of various metallicities. In this paper, we present a progress report on UV spectral templates and spectral diagnostics.

Heap, Sara R.↗

NASA NTRS2010

Quantification of Juniperus Ashei Pollen Production for the Development of Forecasting Models

Juniperus ashei pollen is considered one of the most allergenic species of Cupressaceae in North America. Juniperus ashei is distributed throughout central Texas, Northern Mexico, the Arbuckle Mountains of south central Oklahoma, and the Ozark Mountains of northern Arkansas and southwestern Missouri. The large amount of airborne pollen that J. ashei produces affects inhabitants of cities and towns adjacent to juniper woodland areas and because juniper pollen can be transported over long distances, it affects populations that are far away. In order to create a dynamic forecast system for allergy and asthma sufferers, pollen production must be estimated. Estimation of pollen production requires the estimation of male cone production. Two locations in the Arbuckle Mountains of Oklahoma and 4 locations in the Edwards Plateau region of Texas were chosen as sampling sites. Trees were measured to determine approximate size. Male to female ratio was determined and pollen cone production was estimated using a qualitative scale from 0 to 2. Cones were counted from harvested 1/8 sections of representative trees. The representative trees were measured and approximate surface area of the tree was calculated. Using the representative tree data, the number of cones per square meter was calculated for medium production (1) and high production (2) trees. These numbers were extrapolated to calculate cone production in other trees sampled. Calibration was achieved within each location's sub-plot by counting cones on 5 branches collected from 5 sides of both high production and medium production trees. The total area sampled in each location was 0.06 hectare and total cone production varied greatly from location to location. The highest production area produced 5.8 million cones while the lowest production area produced 72,000 cones. A single representative high production tree in the Arbuckle Mountains produced 1.38 million cones. The number of trees per location was relatively uniform, but the number of high cone production trees varied greatly. Although there is great diversity in the locations making it difficult to determine which factors are most important, cone production was well correlated with certain stand characteristics including trunk diameter.

Bunderson, L. D.↗

NASA NTRS2015

Stratigraphy of the Caloris Basin, Mercury: Implications for Volcanic History and Basin Impact Melt

Caloris basin, Mercury's youngest large impact basin, is filled by volcanic plains that are spectrally distinct from surrounding material. Post-plains impact craters of a variety of sizes populate the basin interior, and the spectra of the material they have excavated enable the thickness of the volcanic fill to be estimated and reveal the nature of the subsurface. The thickness of the interior volcanic plains is consistently at least 2.5 km, reaching 3.5 km in places, with thinner fill toward the edge of the basin. No systematic variations in fill thickness are observed with long-wavelength topography or azimuth. The lack of correlation between plains thickness and variations in elevation at large horizontal scales within the basin indicates that plains emplacement must have predated most, if not all, of the changes in long-wavelength topography that affected the basin. There are no embayed or unambiguously buried (ghost) craters with diameters greater than 10 km in the Caloris interior plains. The absence of such ghost craters indicates that one or more of the following scenarios must hold: the plains are sufficiently thick to have buried all evidence of craters that formed between the Caloris impact event and the emplacement of the plains; the plains were emplaced soon after basin formation; or the complex tectonic deformation of the basin interior has disguised wrinkle-ridge rings localized by buried craters. That low-reflectance material (LRM) was exposed by every impact that penetrated through the surface volcanic plains provides a means to explore near-surface stratigraphy. If all occurrences of LRM are derived from a single layer, the subsurface LRM deposit is at least 7.5-8.5 km thick and its top likely once made up the Caloris basin floor. The Caloris-forming impact would have generated a layer of impact melt 3-15 km thick; such a layer could account for the entire thickness of LRM. This material would have been derived from a combination of lower crust and upper mantle.

Cratering↗

NASA NTRS2017

Determination of the Risk of Radiation-Associated Circulatory and Cancer Disease Mortality in a NASA Early Astronaut Cohort

Of the many possible health challenges posed during extended exploratory missions to space, the effects of space radiation on cardiovascular disease and cancer are of particular concern. There are unique challenges to estimating those radiation risks; care and appropriate and rigorous methodology should be applied when considering small cohorts such as the NASA astronaut population. The objective of this work was to determine if there was sufficient evidence for excess risk of cardiovascular disease and cancer in early NASA astronaut cohorts. NASA astronauts in selection groups 1-7 were chosen; this relatively homogeneous cohort consists of 73 white males, who unlike today's astronauts, maintained similar smoking and drinking habits to the general US population, and have published radiation doses. The participants flew in space on missions Mercury through Shuttle and received space radiation doses between 0-74.1 milligrays. Cause of death information was obtained from the Lifetime Surveillance of Astronaut Health (LSAH) program at NASA Johnson Space Center. Mortality was compared with the US male population. Trends of mortality with dose were assessed using a logistic model, fitted by maximum likelihood. Only 32 (43.84 percent) of the 73 early astronauts have died. Standard mortality ratios (SMRs) for cancer (n=7, SMR=43.4, 95 percent CI 17.8, 84.9), all circulatory disease (n=7, SMR=33.2, 95 percent CI 13.7, 65.0), and ischemic heart disease (IHD) (n=5, SMR=40.1, 95 percent CI 13.2, 89.4) were significantly lower than for the US white male population. For cerebrovascular disease, the upper confidence interval for SMR included 100, indicating it was not significantly different from the US population (n=2, SMR = 77.0, 95 percent CI 9.4, 268.2). The power of the study is low and remains below 10 percent even when risks 10 times those reported in the literature are assumed. Due to small sample size, there is currently insufficient statistical power to evaluate space radiation exposure effects on mortality in NASA astronauts. In addition to a comprehensive longitudinal study of NASA astronauts, a research strategy of low dose epidemiology data integration with cell and animal studies should be utilized for space radiation risk assessment in the astronauts.

Elgart, S. R.↗

NASA NTRS2018

Radiation Exposure and Mortality from Cardiovascular Disease and Cancer in Early NASA Astronauts: Space for Exploration

Elgart, S. R.↗

NASA NTRS2024

Overview of Two Decision-Support Systems for Viticulture

Sustainable water management is one of the most challenging issues of our time, especially in the arid western U.S. Adequate water supplies are crucial to maintaining the health of communities, rivers, and wildlife, and nothing is more important to agriculture’s ability to produce food for the world’s growing population. Maximizing the benefits of our water supplies requires careful measurement of their availability and use. For irrigated agriculture, satellite-based estimates of evapotranspiration (ET) provide a measure of the water used to grow food — the biggest share of water consumption in most arid environments around the world. However, access to ET data has been limited and expensive, keeping it out of the hands of most water users and decision-makers. OpenET provides open, easily accessible satellite-based ET data for water management support. The OpenET collaborative includes leading national and international experts in remote sensing of ET, cloud computing, and water policy, partnered with nationally recognized web development teams and leaders in the western agriculture and water management communities. The system can be accessed at https://openetdata.org/.

Overview↗

NASA NTRS2005

Testing the Gamma-Ray Burst Energy Relationships

Building on Nakar & Piran's analysis of the Amati relation relating gamma-ray burst peak energies E(sub p) and isotropic energies E(sub iso ) we test the consistency of a large sample of BATSE bursts with the Amati and Ghirlanda (which relates peak energies and actual gamma-ray energies E(sub gamma)) relations. Each of these relations can be exp ressed as a ratio of the different energies that is a function of red shift (for both the Amati and Ghirlanda relations) and beaming fraction f(sub B) (for the Ghirlanda relation). The most rigorous test, whic h allows bursts to be at any redshift, corroborates Nakar & Piran's r esult - 88% of the BATSE bursts are inconsistent with the Amati relat ion - while only l.6% of the bursts are inconsistent with the Ghirlan da relation if f(sub B) = 1. Modelling the redshift distribution resu lts in an energy ratio distribution for the Amati relation that is sh ifted by an order of magnitude relative to the observed distributions; any sub-population satisfying the Amati relation can comprise at mos t approx. 18% of our burst sample. A similar analysis of the Ghirland a relation depends sensitively on the beaming fraction distribution f or small values of f(sub B); for reasonable estimates of this distrib ution about a third of the burst sample is inconsistent with the Ghir landa relation. Our results indicate that these relations are an artifact of the selection effects of the burst sample in which they were f ound; these selection effects may favor sub-populations for which the se relations are valid.

Band, David L.↗

DOE OSTI2022

The Poor Old Heart of the Milky Way

Our Milky Way should host an ancient, metal-poor, and centrally concentrated stellar population, which reflects the star formation and enrichment in the few most massive progenitors that coalesced at high redshift to form the proto-Galaxy. While metal-poor stars are known to reside in the inner few kiloparsecs of our Galaxy, current data do not yet provide a comprehensive picture of such a metal-poor "heart" of the Milky Way. We use information from Gaia Data Release 3, especially the XP spectra, to construct a sample of 2 million bright (G BP < 15.5 mag) giant stars within 30° of the Galactic center (GC) with robust [M/H] estimates, δ[M/H] ≲ 0.1. For ~1.25 million stars we calculate orbits from Gaia Radial Velocity Spectrometer velocities and astrometry. This sample reveals an extensive, ancient, and metal-poor population that includes ~18,000 stars with -2.7 < [M/H] < -1.5, representing a stellar mass of ≳5 × 10 7 M ⊙ . The spatial distribution of these [M/H] < -1.5 stars has a Gaussian extent of only σ R$_{GC}$ around the GC, with most orbits confined to the inner Galaxy. At high orbital eccentricities, there is clear evidence for accreted halo stars in their pericentral orbit phase. Most stars show [α/Fe] enhancement and [Al/Fe]–[Mn/Fe] abundances expected for an origin in the more massive portions of the proto-Galaxy. Stars with [M/H] < -2 show no net rotation, whereas those with [M/H] ~ -1 are rotation dominated. These central, metal-poor stars most likely predate the oldest disk population (τ age ≈ 12.5 Gyr), which implies that they formed at z ≳ 5, forging the proto-Milky Way.

79 ASTRONOMY AND ASTROPHYSICS↗

NASA NTRS1998

Strontium transfer from maternal skeleton to the fetus estimated on the basis of the Techa river data

Measurements of 90Sr in human bone of inhabitants of the Techa river region were started in 1951, and since 1974 the Techa river population has been studied with a whole-body counter. One of the dosimetric tasks that could be decided using data on 90Sr measurements is direct evaluation of strontium transfer to the fetus from the maternal skeleton. Six cases were selected for which 90Sr measurements were available both for stillborn infants and their mothers. The ratio of 90Sr concentrations in fetal bone to maternal bone for the year of pregnancy has been evaluated. Two clusters of values were found and the difference between clusters could be explained by age-dependent features of maternal bone formation and remodelling. When the mother's 90Sr intake occurred in the period of intensive compact bone growth, the transfer coefficient was very low (0.012-0.032). If 90Sr ingestion occurred during the woman's reproductive age, the transfer to fetus was equal to 0.21-0.26.

Non-NASA Center↗

DOE OSTI2022

The gMOSS: the galaxy survey and galaxy populations of the large homogeneous field

ABSTRACT We present the gMOSS (Galaxies of Medium-band One-meter Schmidt telescope Survey) catalogue of ∼19 000 galaxies in 20 filters (4 broad-band SDSS and 16 medium-band filters). We observed 2.386 deg2 on the central part of the HS47.5-22 field with the 1-m Schmidt telescope of the Byurakan Astrophysical Observatory. The gMOSS is a complete flux-limited sample of galaxies with a threshold magnitude of r SDSS ≤ 22.5 AB. From photometric measurements with 16 medium-band filters and u SDSS, we get spectral energy distributions for each object in the field, which are used for further analysis. Galaxy classification and photometric redshift estimation based on spectral template matching with zebra software. The obtained redshift accuracy is σNMAD < 0.0043. Using the SED-fitting cigale code, we obtained the main properties of the stellar population of galaxies, such as rest-frame (u − r)res colour, stellar mass, extinction, and mass-weighted age with a precision of 0.16 ± 0.07 mag, 0.14 ± 0.04 dex, 0.27 ± 0.1 mag, and 0.08 ± 0.04 dex, respectively. Using a dust-corrected colour–mass diagram, we divided the full sample into populations of red and blue galaxies and considered the dependencies between stellar mass and age. Throughout cosmic time, red sequence galaxies remain older and more massive than blue cloud galaxies. The star formation history of a complete subsample of galaxies selected in the redshift range 0.05 ≤ z ≤ 0.015 with <$\mathrm{log} M \mathrm{\gt }_\mathrm{[M_\odot ]}$>8.3 shows an increase in the SFRD up to z ∼ 3, under the results obtained in earlier studies.

79 ASTRONOMY AND ASTROPHYSICS↗

DOE OSTI2024

Chemical clocks: using otolith geochemistry to enhance estimation of age and growth of white hake (Urophycis tenuis)

The white hake (Urophycis tenuis) is a groundfish distributed throughout the Gulf of Maine. Catch advice is based on stock assessments done with age-based population dynamics models; however, otolith aging is challenging because of unclear growth increments. To address this concern, we compared the consistency of aging with counts of visual annuli to that of aging with cycles of elemental concentrations measured by using laser ablation inductively coupled plasma mass spectrometry. We tested the hypothesis that oscillations in both environmental conditions and internal physiology through time influence uptake of elements during otolith mineralization. Concentrations of manganese, in comparison with those of the other investigated trace elements (magnesium, strontium, and barium), had the most promising correlation with visual growth increments (~100% age agreement, ±1 year), offering an additional tool to enhance increment identification. In our examination of 550 otoliths collected during 2007–2021, we found that white hake lived a maximum of 10.3 years and exhibited sexual dimorphism in maximum length and age. By using generated von Bertalanffy growth functions, L(t)=110(1–e–0.113(t+0.45)) for males and L(t)=140(1–e–0.113(t–0.30)) for females (where L(t) is length at time t), size and age at maturity were calculated for males (37.4 cm in total length (TL), 3.3 years) and females (47.4 cm TL, 4.2 years). These results demonstrate that otolith geochemistry can be used to improve the accuracy and precision of the estimation of fish age and maturity, even for challenging species.

59 BASIC BIOLOGICAL SCIENCES↗