155 research outputs found
Race, Ethnicity, Income Concentration and 10-Year Change in Urban Greenness in the United States
Background: Cross-sectional studies suggest urban greenness is unequally distributed by neighborhood demographics. However, the extent to which inequalities in greenness have changed over time remains unknown. Methods: We estimated 2001 and 2011 greenness using Moderate-resolution Imaging Spectroradiometer (MODIS) satellite-derived normalized difference vegetative index (NDVI) in 59,483 urban census tracts in the contiguous U.S. We fit spatial error models to estimate the association between baseline census tract demographic composition in 2000 and (1) 2001 greenness and (2) change in greenness between 2001 and 2011. Results: In models adjusted for population density, climatic factors, housing tenure, and Index of Concentration at the Extremes for income (ICE), an SD increase in percent White residents (a 30% increase) in 2000 was associated with 0.021 (95% CI: 0.018, 0.023) higher 2001 NDVI. We observed a stepwise reduction in 2001 NDVI with increased concentration of poverty. Tracts with a higher proportion of Hispanic residents in 2000 lost a small, statistically significant amount of greenness between 2001 and 2011 while tracts with higher proportions of Whites experienced a small, statistically significant increase in greenness over the same period. Conclusions: Census tracts with a higher proportion of racial/ethnic minorities, compared to a higher proportion of White residents, had less greenness in 2001 and lost more greenness between 2001 and 2011. Policies are needed to increase greenness, a health-promoting neighborhood asset, in disadvantaged communities
Spectroscopic Description of the E1 State of Mo Nitrogenase Based on Mo and Fe X‑ray Absorption and Mössbauer Studies
Mo nitrogenase (N2ase) utilizes a two-component protein system, the catalytic MoFe and its electron-transfer partner FeP, to reduce atmospheric dinitrogen (N2) to ammonia (NH3). The FeMo cofactor contained in the MoFe protein serves as the catalytic center for this reaction and has long inspired model chemistry oriented toward activating N2. This field of chemistry has relied heavily on the detailed characterization of how Mo N2ase accomplishes this feat. Understanding the reaction mechanism of Mo N2ase itself has presented one of the most challenging problems in bioinorganic chemistry because of the ephemeral nature of its catalytic intermediates, which are difficult, if not impossible, to singly isolate. This is further exacerbated by the near necessity of FeP to reduce native MoFe, rendering most traditional means of selective reduction inept. We have now investigated the first fundamental intermediate of the MoFe catalytic cycle, E1, as prepared both by low-flux turnover and radiolytic cryoreduction, using a combination of Mo Kα highenergy-resolution fluorescence detection and Fe K-edge partial-fluorescence-yield X-ray absorption spectroscopy techniques. The results demonstrate that the formation of this state is the result of an Fe-centered reduction and that Mo remains redoxinnocent. Furthermore, using Fe X-ray absorption and 57Fe Mössbauer spectroscopies, we correlate a previously reported unique species formed under cryoreducing conditions to the natively formed E1 state through annealing, demonstrating the viability of cryoreduction in studying the catalytic intermediates of MoFe
Combining human and artificial intelligence for enhanced AI literacy in higher education
This paper seeks to contribute to the emergent literature on Artificial Intelligence (AI) literacy in higher education. Specifically, this convergent, mixed methods case study explores the impact of employing Generative AI (GenAI) tools and cyber-social teaching methods on the development of higher education students’ AI literacy. Three 8-week courses on advanced digital technologies for education in a graduate program in the College of Education at a mid-western US university served as the study sites. Data were based on 37 participants’ experiences with two different types of GenAI tools–a GenAI reviewer and GenAI image generator platforms. The application of the GenAI review tool relied on precision fine-tuning and transparency in AI-human interactions, while the AI image generation tools facilitated the participants’ reflection on their learning experiences and AI's role in education. Students’ interaction with both tools was designed to foster their learning regarding GenAI's strengths and limitations, and their responsible application in educational contexts. The findings revealed that the participants appeared to feel more comfortable using GenAI tools after their course experiences. The results also point to the students’ enhanced ability to understand and critically assess the value of AI applications in education. This study contributes to existing work on AI in higher education by introducing a novel pedagogical approach for AI literacy development showcasing the synergy between humans and artificial intelligence
Autonomic Dysfunction and Blood Pressure in Glaucoma Patients:The Lifelines Cohort Study
Purpose: We investigated relationship of glaucoma with measurements related to autonomic dysfunction, including heart rate variability (HRV) and blood pressure (BP). Methods: Glaucoma was defined using a questionnaire-based algorithm for 86,841 LifeLines Cohort Study participants. Baseline HRV (root mean square of successive differences [RMSSD]) was calculated from resting electrocardiograms; systolic BP (SBP), diastolic BP (DBP), mean arterial pressure (MAP), and pulse pressure (PP) were oscillometric-based measurements. We used a generalized linear mixed model, adjusted for age, age square, sex, body mass index, and familial relationships to assess the relationship of baseline HRV and BP (continuous and quartiles), hypertension, and antihypertensive medication with glaucoma at follow up (median, 3.8 years). Results: The odds ratio (OR) of glaucoma was 0.95 (95% confidence interval [CI], 0.92-0.99) per unit increase in log-transformed RMSSD (in ms), indicating that autonomous dysfunction (low HRV) is associated with a higher risk of glaucoma. Per 10-mm Hg increase in BP, we found ORs of 1.03 (95% CI, 1.01-1.05; P = 0.015) for SBP, 1.01 (95% CI, 0.97-1.05; P = 0.55) for DBP, 1.03 (95% CI, 1.00-1.06; P = 0.083) for MAP, and 1.04 (95% CI, 1.01-1.07; P = 0.006) for PP. The OR for the lowest versus highest RMSSD quartile was 1.15 (95% CI, 1.05-1.27; P = 0.003). The ORs for the highest versus second quartile were 1.09 (95% CI, 0.99-1.19; P = 0.091) for SBP and 1.13 (95% CI, 1.02-1.24; P = 0.015) for PP. Glaucoma was more common among hypertensives (OR, 1.25; 95% CI, 1.16-1.35; P < 0.001); among those using angiotensin-converting enzyme (ACE) inhibitors (OR, 1.35; 95% CI, 1.18-1.55; P < 0.001); and among those using calcium-channel blockers (OR, 1.19; 95% CI, 1.01-1.40; P = 0.039). Conclusions: Low HRV, high SBP, high PP, and hypertension were associated with glaucoma. Longitudinal studies may elucidate if autonomic dysregulation and high BP also predict glaucoma incidence
The Oregon Health Insurance Experiment: Evidence from the First Year
In 2008, a group of uninsured low-income adults in Oregon was selected by lottery to be given the chance to apply for Medicaid. This lottery provides an opportunity to gauge the effects of expanding access to public health insurance on the health care use, financial strain, and health of low-income adults using a randomized controlled design. In the year after random assignment, the treatment group selected by the lottery was about 25 percentage points more likely to have insurance than the control group that was not selected. We find that in this first year, the treatment group had substantively and statistically significantly higher health care utilization (including primary and preventive care as well as hospitalizations), lower out-of-pocket medical expenditures and medical debt (including fewer bills sent to collection), and better self-reported physical and mental health than the control group.National Institutes of Health. Department of Health and Human ServicesCalifornia HealthCare FoundationJohn D. and Catherine T. MacArthur FoundationNational Institute on Aging (P30AG012810)National Institute on Aging (RC2AGO36631)National Institute on Aging (R01AG0345151)Robert Wood Johnson FoundationAlfred P. Sloan FoundationSmith Richardson FoundationUnited States. Social Security Administration (grant 5 RRC 08098400-03-00 to the National Bureau of Economic Research as part of the SSA Retirement Research Consortium)Centers for Medicare & Medicaid Services (U.S.
Synergies between interstellar dust and heliospheric science with an Interstellar Probe
We discuss the synergies between heliospheric and dust science, the open
science questions, the technological endeavors and programmatic aspects that
are important to maintain or develop in the decade to come. In particular, we
illustrate how we can use interstellar dust in the solar system as a tracer for
the (dynamic) heliosphere properties, and emphasize the fairly unexplored, but
potentially important science question of the role of cosmic dust in
heliospheric and astrospheric physics. We show that an Interstellar Probe
mission with a dedicated dust suite would bring unprecedented advances to
interstellar dust research, and can also contribute-through measuring dust - to
heliospheric science. This can, in particular, be done well if we work in
synergy with other missions inside the solar system, thereby using multiple
vantage points in space to measure the dust as it `rolls' into the heliosphere.
Such synergies between missions inside the solar system and far out are crucial
for disentangling the spatially and temporally varying dust flow. Finally, we
highlight the relevant instrumentation and its suitability for contributing to
finding answers to the research questions.Comment: 18 pages, 7 Figures, 5 Tables. Originally submitted as white paper
for the National Academies Decadal Survey for Solar and Space Physics
2024-203
EarthFinder Probe Mission Concept Study: Characterizing nearby stellar exoplanet systems with Earth-mass analogs for future direct imaging
EarthFinder is a NASA Astrophysics Probe mission concept selected for study
as input to the 2020 Astrophysics National Academies Decadal Survey. The
EarthFinder concept is based on a dramatic shift in our understanding of how
PRV measurements should be made. We propose a new paradigm which brings the
high precision, high cadence domain of transit photometry as demonstrated by
Kepler and TESS to the challenges of PRV measurements at the cm/s level. This
new paradigm takes advantage of: 1) broad wavelength coverage from the UV to
NIR which is only possible from space to minimize the effects of stellar
activity; 2) extremely compact, highly stable, highly efficient spectrometers
(R>150,000) which require the diffraction-limited imaging possible only from
space over a broad wavelength range; 3) the revolution in laser-based
wavelength standards to ensure cm/s precision over many years; 4) a high
cadence observing program which minimizes sampling-induced period aliases; 5)
exploiting the absolute flux stability from space for continuum normalization
for unprecedented line-by-line analysis not possible from the ground; and 6)
focusing on the bright stars which will be the targets of future imaging
missions so that EarthFinder can use a ~1.5 m telescope.Comment: NASA Probe Mission concept white paper for 2020 Astrophysics National
Academies Decadal Surve
- …