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NASA NTRS2001

Remote Sensing of the Urban Heat Island Effect: Assessment of Risks to Human Health and Development of Mitigation Strategies for Sustainable Cities

The growth of cities, both in population and in areal extent, appears as an inexorable process. Urbanization continues at a rapid rate, and it is estimated that by the year 2025, 80% of the world's population will live in cities. One of the more egregious side effects of urbanization is the deterioration in air quality as a result of increased vehicular traffic, industrialization and related activities. In the United States alone, under the more stringent air quality guidelines established by the U.S. Environmental Protection Agency (EPA) in 1997, nearly 300 counties in 34 states will not meet the new air quality standards for ground level ozone. The mitigation of one the physical/environmental characteristics of urbanization known as the urban heat island (UHI) effect, is now being looked at more closely as a possible way to bring down ground level ozone levels in cities and assist states in improving air quality. The UHI results from the replacement of "natural" land covers (e.g., trees, grass) with urban land surface types, such as pavement and buildings. Heat stored in these surfaces is released into the air and results in a "dome" of elevated air temperatures that presides over cities. The effect of this dome of elevated air temperatures is known as the UHI, which is most prevalent about 2-3 hours after sunset on days with intense solar radiation and calm winds. Given the local and regional impacts of the UHI, there are significant potential affects on human health, particularly as related to heat stress and ozone on body temperature regulation and on the cardiovascular and respiratory systems. In this study we are using airborne and satellite remote sensing data to analyze how differences in the urban landscape influence or drive the development of the UHI over four U.S. cities. Additionally, we are assessing what the potential impact is on risks to human health, and developing mitigation strategies to make urban areas more environmentally sustainable.

Quattrochi, Dale A.↗

NASA NTRS2002

High Spatial Resolution Thermal Remote Sensing of the Urban Heat Island Effect: Assessment of Risks to Human Health and Development of Mitigation Strategies for Sustainable Cities

Quattrochi, Dale A.↗

NASA NTRS1975

Studies of discharge mechanisms in high pressure gases-applications to high efficiency high power lasers

By measuring the absorption and emission cantinua of various states in the cesium/xenon molecule, the collisional rates critical in populating the alkali/rare gas excimer levels have been estimated. Cs atomic states that are weakly optically connected to ground have been shown to form excimer levels that are attractive as potential dissociation lasers. In particular, the (Cs/7 2S/Xe) excited molecule appears promising as a source of high energy laser radiation due to its large dissociation energy, stimulated emission cross section, and small population inversion densities. Monitoring of the optically pumped Cs2 molecular absorption profile in the presence of xenon shows a drastic change with increasing xenon pressure for the Cs2C band. Dominant absorption at large xenon densities is centered around approximately 6380 A as opposed to 6300 A for lower perturber pressure.

Cherrington, B. E.↗

NASA NTRSDate not supplied

An Approach to Quantitative Risk Assessment for Combined Spaceflight Hazards: Evaluating the Impact of Short Sleep Durations on Space Crew Cardiovascular Health

Astronauts embarking on long-duration missions will be exposed to multiple spaceflight hazards including radiation, isolation and confinement, distance from Earth, hostile closed environments, and altered gravity. These hazards pose health risks to the crew in-mission and postflight, including risks to cardiovascular health. For radiation, quantitative risk models have been developed that are based on large-scale epidemiological evidence from exposed terrestrial populations, which are extrapolated to account for the difference in radiological effectiveness between ground-based and in-flight exposures. •Cardiovascular diseases (CVD) are multifactorial, therefore multiple risk factors can influence disease risk estimates. •Astronauts with spaceflight experience is a very small population. •To overcome limitations of cohort, population data from presumed equivalent stressors on Earth can be used to quantitatively assess possible risks. •Sleep disruption and short sleep duration are known consequences of spaceflight and are also established risk factors for cardiovascular disease on earth (Pateletal.,2020). •Coronary Heart Disease (CHD), Myocardial Infarction (MI), and stroke are negative health effects due to short sleep durations and sleep disruptions (Yinetal.,2017); (Cappuccio et al., 2010). •A combined CVD risk model including spaceflight stressor such as sleep, stress, radiation, etc.) will provide more precise estimate of risks.

Spaceflight Hazards↗

NASA NTRS2003

Quantification of rat retinal growth and vascular population changes after single and split doses of proton irradiation: translational study using stereology methods

This study quantified architectural and population changes in the rat retinal vasculature after proton irradiation using stereology. A 100 MeV conformal proton beam delivered 8, 14, 20 and 28 Gy as single and split doses to the whole eye. The vascular networks were prepared from retinal digests. Stereological methods were used to obtain the area of the retina and unbiased estimates of microvessel/artery/vein endothelial, pericyte and smooth muscle population, and vessel length. The retinal area increased progressively in the unirradiated, age-matched controls and in the retinas irradiated with 8 and 14 Gy, indicating uniform progressive retinal growth. No growth occurred after 20 and 28 Gy. Regression analysis of total endothelial cell number in all vessels (arteries, veins and capillaries) after irradiation documented a progressive time- and dose-dependent cell loss occurring over 15 to 24 months. The difference from controls was significant (P<0.01) after 28 Gy given in single and split doses and after 20 Gy given as a split dose (P<0.05). Total vessel length in microvessel was significantly shortened at 20 and 28 Gy compared to that of controls (P<0.05). No evident dose recovery was observed in the endothelial populations after split doses. At 10 Gy, the rate of endothelial cell loss, a dose parameter used to characterize the time- and dose-dependent loss of the endothelial population, was doubled.

NASA Discipline Radiation Health↗

NASA NTRS2006

Human Appropriation of Net Primary Production - Can Earth Keep Up?

The amount of Earth's vegetation or net primary production required to support human activities is powerful measure of aggregate human impacts on the biosphere. Biophysical models applied to consumption statistics were used to estimate the annual amount of net primary production in the form of elemental carbon required for food, fibre, and fuel-wood by the global population. The calculations were then compared to satellite-based estimates of Earth's average net primary production to produce a geographically explicit balance sheet of net primary production "supply" and "demand". Humans consume 20% of Earth's net primary production (11.5 petagrams carbon) annually and this percentage varies regionally from 6% (South America) to over 70% (Europe and Asia), and locally from near 0% (central Australia) to over 30,000% (New York City, USA). The uneven footprint of human consumption and related environmental impacts, indicate the degree to which human populations are vulnerable to climate change and suggest policy options for slowing future growth of NPP demand.

Imhoff, Marc L.↗

DOE OSTI2022

Stellar Populations in type Ia supernova host galaxies at intermediate-high redshift: Star formation and metallicity enrichment histories

ABSTRACT We present a summary of our project that studies galaxies hosting type Ia supernova (SN Ia) at different redshifts. We present Gran Telescopio de Canarias (GTC) optical spectroscopy of six SN Ia host galaxies at redshift z ∼ 0.4–0.5. They are joined to a set of SN Ia host galaxies at intermediate-high redshift, which include galaxies from surveys SDSS and COSMOS. The final sample, after a selection of galaxy spectra in terms of signal-to-noise and other characteristics, consists of 680 galaxies with redshift in the range 0.04 < z < 1. We perform an inverse stellar population synthesis with the code fado to estimate the star formation and enrichment histories of this set of galaxies, simultaneously obtaining their mean stellar age and metallicity and stellar mass. After analysing the correlations among these characteristics, we look for possible dependencies of the Hubble diagram residuals and supernova features (luminosity, colour and strength parameter) on these stellar parameters. We find that the Hubble residuals show a clear dependence on the stellar metallicity weighted by mass with a slope of −0.061 mag dex−1, when represented in logarithmic scale, log 〈ZM/Z⊙〉. This result supports our previous findings obtained from gas oxygen abundances for local and SDSS-survey galaxies. Comparing with other works from the literature that also use the stellar metallicity, we find a similar value, but with more precision and a better significance (2.08 versus ∼ 1.1), due to the higher number of objects and wider range of redshift of our sample.

Millán-Irigoyen, I. (ORCID:0000000341155140)↗

DOE OSTI2023

A Robust Parallel Distributed State Estimation for Large Scale Distribution Systems

The growing need and interest in real-time monitoring of large distribution networks motivated by the rapid population of renewable sources, EVs and etc. demand a computationally efficient state estimation framework. Furthermore, this paper presents an improved computational framework for implementing a robust state estimator using a multi-core processor. The main contribution of the paper is the proposed computational framework along with two partitioning strategies which enable fast and robust state estimation for large scale radial and/or meshed distribution systems. Formulation of the proposed method and its implementation are described in detail. Performance of the estimator is tested by simulations first using a small 84-bus radial distribution system. Then the method’s scalability is demonstrated by simulations on two very large scale distribution networks one configured radially and the other meshed each containing over 12,500 buses.

42 ENGINEERING↗

DOE OSTI2020

Extinction Dynamics of the Foot-and-Mouth Disease Virus Carrier State Under Natural Conditions

Foot-and-mouth disease (FMD) is one of the most economically important livestock diseases worldwide. Following the clinical phase of FMD, a large proportion of ruminants remain persistently infected for extended periods. Although extinction of this carrier state occurs continuously at the animal and population levels, studies vary widely in their estimates of the duration of persistent infection. There is a need for robust statistical models to capture the dynamics of persistent infection for the sake of guiding FMD control and trade policies. The goal of the current study was to develop and assess statistical models to describe the extinction of FMD virus (FMDV) persistent infection using data from primary longitudinal studies of naturally infected cattle and Asian buffalo in Vietnam and India. Specifically, accelerated failure time (AFT) models and generalized linear mixed models (GLMM) were developed to predict the probability of persistent infection in seropositive animals and identified carriers at the individual animal level at sequential time points after outbreaks. The primary studies were analyzed by country and combined using an individual-participant data meta-analysis approach. The models estimated similar trends in the duration of persistent infection for the study/species groups included in the analyses, however the significance of the trends differed between the models. The overall probabilities of persistent infection were similar as predicted by the AFT and GLMM models: 6 months: 99% (AFT) /80% (GLMM), 12 months: 51% (AFT) /32% (GLMM), 18 months: 6% (AFT) /5% (GLMM), 24 months: 0.8% (AFT) /0.6% (GLMM). These models utilizing diverse and robust data sets predict higher probabilities of persistence than previously published, suggesting greater endurance of carriers subsequent to an outbreak. This study demonstrates the utility of statistical models to investigate the dynamics of persistent infection and the importance of large datasets, which can be achieved by combining data from several smaller studies in meta-analyses. Results of this study enhance current knowledge of the FMDV carrier state and may inform policy decisions regarding FMDV persistent infection.

59 BASIC BIOLOGICAL SCIENCES↗

DOE OSTI2022

BASS. XXVI. DR2 Host Galaxy Stellar Velocity Dispersions

We present new central stellar velocity dispersions for 484 Sy 1.9 and Sy 2 from the second data release of the Swift/BAT AGN Spectroscopic Survey (BASS DR2). This constitutes the largest study of velocity dispersion measurements in X-ray-selected obscured active galactic nuclei (AGN) with 956 independent measurements of the Ca II H and K λ3969, 3934 and Mg I λ5175 region (3880–5550 Å) and the calcium triplet region (8350–8730 Å) from 642 spectra mainly from VLT/X-Shooter or Palomar/DoubleSpec. Our sample spans velocity dispersions of 40–360 km s 1 , corresponding to 4–5 orders of magnitude in black hole mass (M BH = 10 5.5-9.6 M ⊙ ), bolometric luminosity (L bol ~ 10 42–46 erg s -1 ), and Eddington ratio (L/L Edd ~ 10 -5 to 2). For 281 AGN, our data and analysis provide the first published central velocity dispersions, including six AGN with low-mass black holes (M BH = 10 5.5-6.5 M ⊙ ), discovered thanks to high spectral resolution observations (σ inst ~ 25 km s -1 ). The survey represents a significant advance with a nearly complete census of velocity dispersions of hard X-ray–selected obscured AGN with measurements for 99% of nearby AGN (z < 0.1) outside the Galactic plane (|b| > 10°). The BASS AGN have much higher velocity dispersions than the more numerous optically selected narrow-line AGN (i.e., ~150 versus ~100 km s -1 ) but are not biased toward the highest velocity dispersions of massive ellipticals (i.e., >250 km s -1 ). Despite sufficient spectral resolution to resolve the velocity dispersions associated with the bulges of small black holes (~10 4–5 M ⊙ ), we do not find a significant population of super-Eddington AGN. Using estimates of the black hole sphere of influence from velocity dispersion, direct stellar and gas black hole mass measurements could be obtained with existing facilities for more than ~100 BASS AGN.

79 ASTRONOMY AND ASTROPHYSICS↗

NASA NTRS1984

Determination of rainfall and condensational heating in the South Pacific convergence zone during FGGE SOP-1

The role of cloud related diabatic processes in maintaining the structure of the South Pacific Convergence Zone is discussed. The method chosen to evaluate the condensational heating is a diagnostic cumulus mass flux technique which uses GOES digital IR data to characterize the cloud population. This method requires as input an estimate of time/area mean rainfall rate over the area in question. Since direct observation of rainfall in the South Pacific is not feasible, a technique using GOES IR data is being developed to estimate rainfall amounts for a 2.5 degree grid at 12h intervals.

Robertson, F. R.↗

NASA NTRS1984

The IRAS fast-moving object search

The IR Astronomy Satellite (IRAS) mission has yielded an all-sky IR survey with a detailed pointing history. An analysis is being conducted which will allow an estimate to be made of the detectable population of comets and Apollo asteroids. On the basis of results obtained to date, it is expected that IRAS will detect comets having visual magnitudes lower than 17 if their motions are greater than about 1 arcmin/hour. The positional accuracy of such detections depends on the number of bands in which an object was observed, although the accuracy has so far proved unsuitable for orbit determination. There is no evidence of an undiscovered main belt asteroid population at high ecliptic latitudes.

Davies, J. K.↗

NASA NTRS1989

A model for depolarized radar echoes from Mars

The depolarized radar echoes from Mars are modeled using a combination of remote-sensing observations. The model reproduces the variations of the total radar cross-sections with longitude observed by Goldstone (1986) along 7 S, yields larger magnitudes of total radar cross-sections along 22 N than those along 7 S, and produces depolarized echo spectra that broadly match those observed by the Arecibo radar in 1980 and 1982. The model indicates that volcanoes and lava plains of the Tharsis-Alba Patera, Elysium, and Amazonia regions have the strongest depolarized echoes from the entire planet. Rock populations for the moon and Mars are estimated assuming depolarized radar echoes result from rocks with radii between 1.3 and three times the wavelength.

Thompson, T. W.↗

NASA NTRS2002

Mosaic of CCDs to Survey for Asteroids and Comets

Spacewatch searches for asteroids and comets ranging in location from near-Earth space to regions beyond the orbit of Neptune. We are studying Earth-approaching asteroids, main belt asteroids, comets, Centaurs, and TNOs, as well as the interrelationships of these classes and their bearing on the origin and evolution of the solar system. Spacewatch is described at http://www. lpl. arizona. edu/spacewatch/index.html. The Spacewatch Project has been discovering Earth-approaching asteroids (EAs) steadily and has used the results aggressively to estimate the statistical properties of the EA population. This grant funded Spacewatch to develop and implement a mosaic of CCD imaging detectors for the 0.9-m telescope, to increase that telescope's rate of coverage of sky area while preserving its limiting magnitude.

McMillan, Robert S.↗

NASA NTRS2010

Climate Change and Examples of Combined HyspIRI VSWIR/TIR Advanced Level Products for Urban Ecosystems Analysis

It is estimated that 60-80% of the world population will live in urban environments by the end of this century. This growth of the urban population will effect the climate. This slide presentation examines the use of combined HyspIRI Visible ShortWave Infrared (VSWIR)/Thermal Infrared (TIR) to observe, monitor, measure and model many of the components that comprise urban ecosystems cycles.

Quattrochi, Dale A.↗

NASA NTRS2020

WISEA J083011.95+283716.0: A Missing Link Planetary-mass Object

We present the discovery of WISEA J083011.95+283716.0, the first Y-dwarf candidate identified through the “Backyard Worlds: Planet 9” citizen science project. We identified this object as a red, fast-moving source with a faint W2 detection in multiepoch AllWISE and unWISE images. We have characterized this object with Spitzer and Hubble Space Telescope’s (HST) follow-up imaging. With mid-infrared detections in Spitzerʼs ch1 and ch2 bands and flux upper limits in HST F105W and F125W filters, we find that this object is both very faint and has extremely red colors (ch1 − ch2 = 3.25 ± 0.23 mag, F125W− ch2 ≽ 9.36 mag), consistent with a T(sub eff) ∼ 300 K source, as estimated from the known Y-dwarf population. A preliminary parallax provides a distance of - 11.1+1.5 2.0 pc, leading to a slightly warmer temperature of ∼350 K. The extreme faintness and red HST and Spitzer colors of this object suggest that it may be a link between the broader Y-dwarf population and the coldest known brown dwarf WISE J0855−0714, and may highlight our limited knowledge of the true spread of Y-dwarf colors. We also present four additional “Backyard Worlds: Planet 9” late-T brown dwarf discoveries within 30 pc.

Brown dwarf↗

DOE OSTI2021

Rare Events via Cross-Entropy Population Monte Carlo

Rare events are events that happen with very low frequency. Estimating rare event probabilities using Monte Carlo techniques is computationally expensive, often to the point of intractability, and special methods are required. Importance sampling (IS) is a well known technique that uses a proposal distribution in place of a target distribution to lower the variance of the estimator. Key to the success of IS methods is the choice of a proposal distribution, or the parameters governing the distribution. Adaptive importance sampling improves the parameters of a family or population of proposal distributions iteratively through trials. We present a novel cross-entropy population Monte Carlo algorithm, which adapts the parameters of proposals through the cross-entropy method. The proposed method stands apart from previous work in that we are not optimizing a mixture distribution. Instead, we leverage deterministic mixture weights and optimize the distributions individually through a reinterpretation of the typical derivation of the cross-entropy method. Demonstrations on rare event examples show that the algorithm can outperform existing resampling based population Monte Carlo methods, especially for higher-dimensional problems. Finally, we also demonstrate efficacy on a conjunction analysis problem.

97 MATHEMATICS AND COMPUTING↗

NASA NTRS1985

The secondary radiation under Saturn's A-B-C rings produced by cosmic ray interactions

On the basis of a study of spacecraft data of Saturn, Chenette et al. (1980) concluded that highly relativistic galactic cosmic ray nuclei with magnetic rigidities greater than the Stoermer rigidity cutoff in the plane of Saturn's A-B-C rings along the Pioneer 11 trajectory produced a secondary population of charged particles. The existence of this secondary particle population was confirmed by Randall (1982). Cooper and Simpson (1980) further developed this concept of secondary production of nucleons by cosmic ray nuclei to estimate the yield of secondary neutrons which might, through decay, populate the radiation belt with low-energy electrons and protons. Cooper (1983) reported quantitative Monte Carlo calculations of neutron production in the rings and their decay in the magnetosphere. The present investigation is concerned with a confirmation of the earlier work, and an extension of the studies on the basis of improved spectra for the proton and electron components.

Cooper, J. F.↗