1,721 research outputs found
Educational Inequality in Indiana: The Impact of Socioeconomic Status and Race on ISTEP+ Exam Performance
A gap in education outcomes exists in Indiana for female and male students. The gap in educational outcomes can be seen in the standardized tests that are a requirement for students to take as a part of their education. In Indiana, students in Kâ12 education are required to take the ISTEP+ exam in grades 3â8, and in grade 10 as a graduation requirement. Indiana had 292 school districts or corporations, which were used in this analysis to determine the gap in educational outcomes. The 2011 and 2012 ISTEP+ exam scores were analyzed to determine how SES and race affect male and female performance on the exam for students in all public school corporations or districts in the state of Indiana. In this study, both race (β = â.100, p = .016) and SES (β = â.155, p = .000) negatively affected female student performance, and SES (β = â.266, p = .000) negatively affected male student performance on the ISTEP+ exam
Laser Guide Star for Large Segmented-Aperture Space Telescopes, Part I: Implications for Terrestrial Exoplanet Detection and Observatory Stability
Precision wavefront control on future segmented-aperture space telescopes
presents significant challenges, particularly in the context of high-contrast
exoplanet direct imaging. We present a new wavefront control architecture that
translates the ground-based artificial guide star concept to space with a laser
source aboard a second spacecraft, formation flying within the telescope
field-of-view. We describe the motivating problem of mirror segment motion and
develop wavefront sensing requirements as a function of guide star magnitude
and segment motion power spectrum. Several sample cases with different values
for transmitter power, pointing jitter, and wavelength are presented to
illustrate the advantages and challenges of having a non-stellar-magnitude
noise limited wavefront sensor for space telescopes. These notional designs
allow increased control authority, potentially relaxing spacecraft stability
requirements by two orders of magnitude, and increasing terrestrial exoplanet
discovery space by allowing high-contrast observations of stars of arbitrary
brightness.Comment: Submitted to A
Wildlife as Biosamplers: Contaminants in Hair of Elk Harvested Near the Anaconda Smelter Site
The purpose of this research was to test a new way of investigating biological uptake of smelting-related contaminants with a focus on harvested wildlife. Specific objectives were 1) to collect hair samples from elk (Cervus elaphus) harvested in the vicinity of the Anaconda Smelter National Priority List Site in Montana, 2) to analyze the samples using inductively coupled plasma â mass spectrometry (ICP-MS), and 3) to identify potential elements of concern from the data. Hair samples were collected from 56 elk, and concentration data were processed using a hazard quotient/index approach based on concepts commonly used in fields of ecological and human health risk analyses. Arsenic concentrations in the hair decreased as a function of increasing distance from the Anaconda smelter stack, and 57 % of the elk sampled were identified as animals of concern. For elk harvested within 25 km of the stack, elements of concern were aluminum, arsenic, barium, boron, lithium, manganese, molybdenum, strontium, and vanadium. For elk harvested within 76-101.5 km of the stack, elements of concern were aluminum, barium, boron, lithium, and manganese. Hazard indices for uranium, arsenic, cadmium, and lithium were larger by factors of ~17, 9, 7, and 6, respectively, for elk harvested within 25 km of the stack compared to hazard indices for elk harvested within 76-101.5 km
Sulfur disproportionating microbial communities in a dynamic, microoxicâsulfidic karst system
Biogeochemical sulfur cycling in sulfidic karst systems is largely driven by abiotic and biological sulfide oxidation, but the fate of elemental sulfur (S0) that accumulates in these systems is not well understood. The Frasassi Cave system (Italy) is intersected by a sulfidic aquifer that mixes with small quantities of oxygen-rich meteoric water, creating Proterozoic-like conditions and supporting a prolific ecosystem driven by sulfur-based chemolithoautotrophy. To better understand the cycling of S0 in this environment, we examined the geochemistry and microbiology of sediments underlying widespread sulfide-oxidizing mats dominated by Beggiatoa. Sediment populations were dominated by uncultivated relatives of sulfur cycling chemolithoautotrophs related to Sulfurovum, Halothiobacillus, Thiofaba, Thiovirga, Thiobacillus, and Desulfocapsa, as well as diverse uncultivated anaerobic heterotrophs affiliated with Bacteroidota, Anaerolineaceae, Lentimicrobiaceae, and Prolixibacteraceae. Desulfocapsa and Sulfurovum populations accounted for 12%â26% of sediment 16S rRNA amplicon sequences and were closely related to isolates which carry out autotrophic S0 disproportionation in pure culture. Gibbs energy (âGr) calculations revealed that S0 disproportionation under in situ conditions is energy yielding. Microsensor profiles through the mat-sediment interface showed that Beggiatoa mats consume dissolved sulfide and oxygen, but a net increase in acidity was only observed in the sediments below. Together, these findings suggest that disproportionation is an important sink for S0 generated by microbial sulfide oxidation in this oxygen-limited system and may contribute to the weathering of carbonate rocks and sediments in sulfur-rich environments
Spitzer, Near-Infrared, and Submillimeter Imaging of the Relatively Sparse Young Cluster, Lynds 988e
We present {\it Spitzer} images of the relatively sparse, low luminosity
young cluster L988e, as well as complementary near-infrared (NIR) and
submillimeter images of the region. The cluster is asymmetric, with the western
region of the cluster embedded within the molecular cloud, and the slightly
less dense eastern region to the east of, and on the edge of, the molecular
cloud. With these data, as well as with extant H data of stars
primarily found in the eastern region of the cluster, and a molecular CO
gas emission map of the entire region, we investigate the distribution of
forming young stars with respect to the cloud material, concentrating
particularly on the differences and similarities between the exposed and
embedded regions of the cluster. We also compare star formation in this region
to that in denser, more luminous and more massive clusters already investigated
in our comprehensive multi-wavelength study of young clusters within 1 kpc of
the Sun.Comment: 21 pages, 6 tables, 13 figures. Full resolution figures at:
http://astro.pas.rochester.edu/~tom/Preprints/L988e.pd
Power, Proximity, and Physiology: Does Income Inequality and Racial Composition Amplify the Impacts of Air Pollution on Life Expectancy in the United States?
This study advances research at the intersection of environmental degradation, social stratification, and population health in the United States. Expanding the theoretical principles of power, proximity, and physiology, we hypothesize that the harmful effect of fine particulate matter on life expectancy is greater in states with higher levels of income inequality and larger black populations. To test our hypothesis, we use two-way fixed effects regression analysis to estimate the effect of a three-way interaction between fine particulate matter, income share of the top ten percent, and the percent of the population that is black on state-level average life expectancy for all US states and the District of Columbia (2000â2014). The findings support our hypothesis: the estimated effect of the three-way interaction on average life expectancy is negative and statistically significant, net of various socioeconomic and demographic controls. Using post-estimation techniques, we visually illustrate that the harmful effect of fine particulate matter on life expectancy is especially pronounced in states with both very high levels of income inequality and very large black populations. We conclude by summarizing the theoretical and substantive implications of our findings, the limitations of the study, and potential next steps in this evolving area of interdisciplinary research
Strong variation in weathering of layered rock maintains hillslopeâscale strength under high precipitation
The evolution of volcanic landscapes and their landslide potential are both dependent upon the weathering of layered volcanic rock sequences. We characterize critical zone structure using shallow seismic Vp and Vs profiles and vertical exposures of rock across a basaltic climosequence on Kohala peninsula, Hawaiâi, and exploit the dramatic gradient in mean annual precipitation (MAP) across the peninsula as a proxy for weathering intensity. Seismic velocity increases rapidly with depth and the velocityâdepth gradient is uniform across three sites with 500â600âmm/yr MAP, where the transition to unaltered bedrock occurs at a depth of 4 to 10âm. In contrast, velocity increases with depth less rapidly at wetter sites, but this gradient remains constant across increasing MAP from 1000 to 3000âmm/yr and the transition to unaltered bedrock is near the maximum depth of investigation (15â25âm). In detail, the profiles of seismic velocity and of weathering at wet sites are nowhere monotonic functions of depth. The uniform average velocity gradient and the greater depths of low velocities may be explained by the averaging of velocities over intercalated highly weathered sites with less weathered layers at sites where MAP > 1000âmm/yr. Hence, the main effect of climate is not the progressive deepening of a nearâsurface altered layer, but rather the rapid weathering of high permeability zones within rock subjected to precipitation greater than ~1000âmm/yr. Although weathering suggests mechanical weakening, the nearly horizontal orientation of alternating weathered and unweathered horizons with respect to topography also plays a role in the slope stability of these heterogeneous rock masses. We speculate that where steep, rapidly evolving hillslopes exist, the subâhorizontal orientation of weak/strong horizons allows such sites to remain nearly as strong as their less weathered counterparts at drier sites, as is exemplified by the 50°â60° slopes maintained in the amphitheater canyons on the northwest flank of the island. Copyright Š 2017 John Wiley & Sons, Ltd.Seismic velocity profiles across a basalt climosequence in Hawaiâi reveal that above a particular precipitation threshold, rapid weathering of highâpermeability layers produces intercalated lowâvelocity horizons and dramatically lowers the average seismic velocity of the rock section. However, less permeable layers remain relatively unweathered and thus still contribute significantly to the mechanical competence of the profile, which may explain maintenance of steepâwalled canyons under high precipitation rates. Such observations challenge a topâdown model of progressive weathering (i.e. weakening) of the substrate and therefore suggest that high strength can be maintained even under high precipitation rates, if horizontally layered horizons of different weathering potential exist.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/143701/1/esp4290.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/143701/2/esp4290_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/143701/3/esp4290-sup-0001-SupplementaFiles_FINAL.pd
Study Protocol for a Stepped-Wedge Randomized Cookstove Intervention in Rural Honduras: Household Air Pollution and Cardiometabolic Health
Growing evidence links household air pollution exposure from biomass-burning cookstoves to cardiometabolic disease risk. Few randomized controlled interventions of cookstoves (biomass or otherwise) have quantitatively characterized changes in exposure and indicators of cardiometabolic health, a growing and understudied burden in low- and middle-income countries (LMICs). Ideally, the solution is to transition households to clean cooking, such as with electric or liquefied petroleum gas stoves; however, those unable to afford or to access these options will continue to burn biomass for the foreseeable future. Wood-burning cookstove designs such as the Justa (incorporating an engineered combustion zone and chimney) have the potential to substantially reduce air pollution exposures. Previous cookstove intervention studies have been limited by stove types that did not substantially reduce exposures and/or by low cookstove adoption and sustained use, and few studies have incorporated community-engaged approaches to enhance the intervention
In Vitro and In Vivo Evaluation of Infestation Deterrents Against Lice
The human head louse is a cosmopolitan ectoparasite and frequently infests many people, particularly school-age children. Due to widespread pyrethroid resistance and the lack of efficient resistance management, there has been a considerable interest in the protection of uninfested people and prevention of reinfestation by disrupting lice transfer. In this study, two nonclinical model systems (in vitro and in vivo) were used to determine the efficacy of the infestation deterrents, Elimax lotion and Elimax shampoo, against human head lice or poultry chewing lice, respectively. With in vitro assessments, female head lice exhibited significantly higher avoidance responses to hair tufts treated with either of the test formulations, which led to significantly higher ovipositional avoidance when compared with female lice on control hair tufts. Additionally, both formulations were determined to be competent infestation deterrents in a competitive avoidance test in the presence of a known attractant (head louse feces extract). In in vivo assessments using a previously validated poultry model, Elimax shampoo was determined to be an efficacious deterrent against poultry chewing lice within Menopon spp. and Menacanthus spp
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