1,047 research outputs found
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A new satellite-based global climatology of dust aerosol optical depth
By mass, dust is the largest contributor to global aerosol burden, yet long-term observational records of dust, particularly over the ocean, are limited. Here, two nearly global observational datasets of dust aerosol optical depth τd are created primarily on the basis of optical measurements of the aerosol column from 1) the Moderate Resolution Imaging Spectroradiometer (MODIS) aboard the Terra satellite spanning from 2001 to 2018 and 2) the Advanced Very High Resolution Radiometer (AVHRR) from 1981 to 2018. The quality of the new data is assessed by comparison with existing dust datasets that are spatially more limited. Between 2001 and 2018, τd decreased over Asia and increased significantly over the Sahara, Middle East, and parts of eastern Europe, with the largest increase found over the Aral Sea where emissive playa surfaces have been exposed. These daily, observational, and nearly global records of dust will allow for improvement in understanding the role of dust in climate variability
The effects of air and lip-pressure variations on the motion of a clarinet reed within an artificial embouchure
To observe the influence of air and lip-pressure variations on reed motion, a blowing chamber containing an artificial-embouchure device was constructed into which a clarinet was inserted and sealed at the barrel joint. A DC light source was directed through the bell end of the clarinet into a photo transistor mounted near the mouthpiece. Light fluctuations produced by the reed's movement were converted to voltages and directed to an analog-to-digital converter unit interfaced with an Apple lie computer. In air-pressure experiments, lip pressure was held constant while air pressure was varied. In lip-pressure experiments, air pressure was held constant while lip pressure was varied. Intensities were measured on a sound-level meter and air-pressure was monitored via a U-tube water manometer connected to the chamber; thus, the reed's vibrational patterns were observed at specific air pressures, lip pressures, and itensities
Reconstructing Summer Upper-Level Flow In The Northern Rocky Mountains Using An Alpine Larch (Larix Lyallii) Tree-Ring Chronology
Mid-latitude mesoscale weather in the climatological summer is heavily influenced by fluctuations in synoptic-scale circulation patterns. Previous research has linked Arctic amplification to alterations in summer synoptic climatology, leading to more extreme weather events in the mid-latitudes. In this study we reconstruct seasonal (JJA) upper-level (500 hPa) atmospheric flow for four geographic locations in the mid-latitudes using an alpine larch (Larix lyallii Parl.) tree-ring chronology derived from western Montana. Our goal is to assess the long-term (400+ year) stability of upper-level flow to place the observed trends in a historical context. Spatial pattern correlations indicate that tree growth increases when meridional flow and zonal flow are strong west (r = 0.504, p = 0.001, n = 37) and north (r = 0.642, p < 0.001, n = 37) of the study site, respectively. Tree growth declines when meridional flow and zonal flow are strong east (r = -0.497, p = 0.001, n = 37) and south (r = -0.584, p < 0.001, n = 37) of the study site, respectively. Our 444-year climate reconstructions of 500 hPa flow show that ridging is becoming more intense in recent decades while troughs are declining in intensity
Tertius Romane: An Examination Of Muscovite Mystical Political Theology
The relationship between the Russian Orthodox Church and Russian state has received less than required academic attention. In the post-Soviet space, the Russian Church has again begun to interact with the Russian state. Through research of Russian primary sources including chronicles, vitae of princes, and various correspondence, this paper traces the origins of the relationship between Church and State and examines both the mystical and political theological actualities of such. This thesis demonstrates similarities, historical themes, and aspects of Church and State interactions through a comparison to Ernst Kantorowicz’s The King’s Two Bodies: A Study in Mediaeval Political Theology that can be applied to examine modern day Russian Church and State political theology
Conserved Non-Coding Element Derived Regulation of the Meis2.2 Homeobox Gene During Embryonic Development
The homeobox-containing Meis gene family includes at least four members that are expressed in spatially and temporally conserved fashion throughout development in all vertebrates examined thus far. Products of the Meis genes function as cofactors, interacting with other transcription factors and DNA to assist in the regulation of transcription. Most importantly, they appear to work with the Hox proteins as well as other homeobox genes’ products including Pbx proteins. At this time, little is known about the regulation of the Meis genes. Using phylogenetic footprinting to search for regulatory elements in association with the Meis family of homeobox-containing genes, we identified a highly conserved element located downstream of the Meis2 gene that we have called Meis2 Downstream Element 1 (m2de1). This putative enhancer is conserved in sequence and position across the genomes of all vertebrates examined. Furthermore, the m2de1 element contains several putative transcription factor binding sites. In this study, we have demonstrated the ability of m2de1 to drive reporter gene expression through microinjection derived transgenic analysis. Reporter gene expression was observed in the developing brain of zebrafish embryos in a manner consistent with endogenous Meis2 expression, potentially implicating the m2de1 element with cis-regulatory function
The influence of habitual fluid intake on energy balance
Epidemiologic data have linked chronic low fluid intake (i.e., underhydration) with greater incidence of obesity, but the underlying mechanisms behind this association are unclear. No study has assessed the direct effect of underhydration on energy balance (EB), which is inclusive of energy consumed from food or fluid (EI) and energy expended from resting metabolism (RMR), the thermic effect of food (TEF), and physical activity (PAEE). Underhydration increases release of the fluid regulatory hormone arginine vasopressin (AVP) to conserve total body water. However, chronic elevations in AVP may cause metabolic changes including alterations in cortisol release that could influence one’s propensity toward developing obesity and metabolic disease. Thus, the purpose of the present study was to characterize the associations between habitual fluid intake and behavioral, perceptual, and physiologic factors influencing energy balance to inform the development of effective intervention strategies promoting adequate hydration for metabolic health. Healthy male participants with low, moderate, and high habitual fluid intake completed measures of EI and fluid intake (TFI), PAEE for seven days, as well as measures of hydration status for four of these days. Participants also came to the lab for assessments of RMR, TEF, fasting and postprandial changes in appetite and thirst, food reward, and salivary and hematological measures of hormonal responses to hydration status. Higher habitual fluid intake was associated with higher RMR and increased PAEE, but there was no effect on overall EB. There was no association between habitual fluid intake and appetite ratings. Lower habitual fluid intake and a flatter diurnal cortisol slope were independently associated with liking of high fat sweet foods and wanting of high fat savory foods, respectively, but twenty-four-hour urinary osmolality was not associated with salivary cortisol dynamics (peak cortisol, cortisol awakening response, diurnal cortisol slope). These data suggest increased fluid intake is a promising target for future interventions to aid with weight maintenance from both a physiologic and behavioral standpoint
Comparative Microscopic Anatomy And Tensile Strength Of Plumage From Various Color Phases In The Eastern Screech Owl (MEGASCOPS ASIO)
The Eastern Screech Owl (Megascops asio) is a polymorphic species with rufous and gray tones that exhibits clinal variation. The rufous morph is virtually nonexistent in the northern and westernmost parts of its range. The rufous morph predominates in humid deciduous areas in the center of the eastern screech owl range. While color polymolphism is exhibited widely in birds there is no apparent explanation for the maintenance of clinal variation. Studies have noted differences in oxygen consumption across eastern screech owl color morphs. Differences in feather morphology could lead to difference in thermal insulation and physical resistance
Future changes in tropical cyclone activity in the North Indian Ocean projected by high-resolution MRI-AGCMs
Open Access at publisher's web site: http://www.springerlink.com/content/b682734237171631
Critical experiential education : integrating critical pedagogy, social justice education, and experiential education to re-imagine teaching and learning
This dissertation examines the lived experiences of teachers, students, and administrators at a public charter school based on progressive philosophies such as experiential education, restorative justice, and social justice. Through a qualitative constructivist grounded theory approach, this research discusses the ways that experiential education influences the teaching and learning at this school. Interviews and observations were utilized to gain a more thorough understanding of the ways in which these progressive pedagogies are enacted. Experiential education provides a co-created and student-centered learning environment that prepares students for lives as citizens of local and global communities. As a philosophy, experiential education can be utilized to help make meaning of experiences and motivate future actions. Central to this project is the proposal of a new frame for critical experiential education that intentionally integrates social justice education, critical pedagogy, and experiential education. The creation of this frame attempts to put these seemingly disparate fields into conversation with one another thereby intertwining the elements of each such that the gaps found amongst them can be filled. The value of this work is the ability to create a more robust and comprehensive understanding and implementation of a frame of critical experiential education that is intentionally grounded in aspects of power, justice, context, history, and identity in order to recognize and encourage future action towards the alleviation of oppression in all its forms
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Seasonal forecasts of North Atlantic tropical cyclone activity in the North American Multi-Model Ensemble
The North American Multi-Model Ensemble (NMME)-Phase II models are evaluated in terms of their retrospective seasonal forecast skill of the North Atlantic (NA) tropical cyclone (TC) activity, with a focus on TC frequency. The TC identification and tracking algorithm is modified to accommodate model data at daily resolution. It is also applied to three reanalysis products at the spatial and temporal resolution of the NMME-Phase II ensemble to allow for a more objective estimation of forecast skill. When used with the reanalysis data, the TC tracking generates realistic climatological distributions of the NA TC formation and tracks, and represents the interannual variability of the NA TC frequency quite well. Forecasts with the multi-model ensemble (MME) when initialized in April and later tend to have skill in predicting the NA seasonal TC counts (and TC days). At longer leads, the skill is low or marginal, although one of the models produces skillful forecasts when initialized as early as January and February. At short lead times, while demonstrating the highest skill levels the MME also tends to significantly outperform the individual models and attain skill comparable to the reanalysis. In addition, the short-lead MME forecasts are quite reliable. At regional scales, the skill is rather limited and mostly present in the western tropical NA and the Caribbean Sea. It is found that the overall MME forecast skill is limited by poor representation of the low-frequency variability in the predicted TC frequency, and large fluctuations in skill on decadal time scales. Addressing these deficiencies is thought to increase the value of the NMME ensemble in providing operational guidance
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