1,614 research outputs found
Effective use of study-team review techniques in fifth and sixth grade social studies.
Thesis (Ed.M.)--Boston Universit
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The geology of Tarrant County
Accompanied by 2 foldout maps -- Map 1 : Topographic map of the T.C.U. vicinity. Map 2 : Geological map of Tarrant County, Texas. University of Texas bulletin ; no. 1931 : June 1, 1919UT Librarie
Determining the Novel Pathogen Neodothiora populina as the Causal Agent of the Aspen Running Canker Disease in Alaska
Neodothiora populina Crous, G.C. Adams & Winton was determined to be a new pathogen of trembling aspen (Populus tremuloides) growing in Alaska, based on completion of Koch’s Postulates in replicated forest and growth chamber inoculation trials. The pathogen is responsible for severe damage and widespread rapid mortality of sapling to mature aspen (≥ 80 years) in the boreal forests of interior Alaska, due to large diffuse annual (1–2 years) cankers. Isolation of the pathogen was challenging, and identification based on cultural characters was difficult. Fruiting bodies were not found on wild diseased trees, but erumpent pycnidia were found in bark overlying cankers on several stems inoculated with pure cultures
Widespread Mortality of Trembling Aspen (Populus tremuloides) Throughout Interior Alaskan Boreal Forests Resulting from a Novel Canker Disease
Over the past several decades, growth declines and mortality of trembling aspen throughout western Canada and the United States have been linked to drought, often interacting with outbreaks of insects and fungal pathogens, resulting in a “sudden aspen decline” throughout much of aspen’s range. In 2015, we noticed an aggressive fungal canker causing widespread mortality of aspen throughout interior Alaska and initiated a study to quantify potential drivers for the incidence, virulence, and distribution of the disease. Stand-level infection rates among 88 study sites distributed across 6 Alaska ecoregions ranged from \u3c 1 to 69%, with the proportion of trees with canker that were dead averaging 70% across all sites. The disease is most prevalent north of the Alaska Range within the Tanana Kuskokwim ecoregion. Modeling canker probability as a function of ecoregion, stand structure, landscape position, and climate revealed that smaller-diameter trees in older stands with greater aspen basal area have the highest canker incidence and mortality, while younger trees in younger stands appear virtually immune to the disease. Sites with higher summer vapor pressure deficits had significantly higher levels of canker infection and mortality. We believe the combined effects of this novel fungal canker pathogen, drought, and the persistent aspen leaf miner outbreak are triggering feedbacks between carbon starvation and hydraulic failure that are ultimately driving widespread mortality. Warmer early-season temperatures and prolonged late summer drought are leading to larger and more severe wildfires throughout interior Alaska that are favoring a shift from black spruce to forests dominated by Alaska paper birch and aspen. Widespread aspen mortality fostered by this rapidly spreading pathogen has significant implications for successional dynamics, ecosystem function, and feedbacks to disturbance regimes, particularly on sites too dry for Alaska paper birch
Light and the Manifestation of Performance Place: The Experience of Spaces and Places Through a Different Light.
Through the practice-based lens of the Night in the Garden at the Royal Botanic Garden Edinburgh (2014) this paper explores how environments, both built and green, can become something powerfully augmented in the regeneration of cities and towns, and introduces the human experience of unexpected events as an affordance of access and belonging. In the last two decades the explosion of the ‘light festival’ as a global phenomenon has created a new night-time language of temporary performance. Our urban environments are straining to develop unique visual representations that have driven a new kind of tourism. The alien performances that play out across our urban centres bring a return to the joy of the unique and the carnivalesque and are situated within the environments that we recognise so differently during the day. This creative practice led perspective, supported exploration of audience engagement and asked questions of how personal and shared experiences are generated and broadcast; whilst recognising this approach as part of a wider place-making phenomena, where visual culture awakens sleeping spaces. The urban domain is a canvas for storytelling open to change each time the festival rolls into town, where physical structures remain unaltered, but our perception of them becomes reanimated
Microbial and metabolic succession on common building materials under high humidity conditions.
Despite considerable efforts to characterize the microbial ecology of the built environment, the metabolic mechanisms underpinning microbial colonization and successional dynamics remain unclear, particularly at high moisture conditions. Here, we applied bacterial/viral particle counting, qPCR, amplicon sequencing of the genes encoding 16S and ITS rRNA, and metabolomics to longitudinally characterize the ecological dynamics of four common building materials maintained at high humidity. We varied the natural inoculum provided to each material and wet half of the samples to simulate a potable water leak. Wetted materials had higher growth rates and lower alpha diversity compared to non-wetted materials, and wetting described the majority of the variance in bacterial, fungal, and metabolite structure. Inoculation location was weakly associated with bacterial and fungal beta diversity. Material type influenced bacterial and viral particle abundance and bacterial and metabolic (but not fungal) diversity. Metabolites indicative of microbial activity were identified, and they too differed by material
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Supporting Information: Membrane-less and Non-Evaporative Desalination of Hypersaline Brines by Temperature Swing Solvent Extraction
Hypersaline brines are of growing environmental importance but are technologically under-served by today’s desalination methods. Temperature swing solvent extraction (TSSE) is a radically different desalination technology that is membrane-less and not based on evaporative phase change. TSSE utilizes low-temperature heat and a low-polarity solvent with temperature-dependent water solubility for the selective extraction of water over salt from saline feeds. This study demonstrates TSSE desalination of high-salinity brines simulated by NaCl solutions with three amine solvents: diisopropylamine (DIPA), N-ethylcyclohexylamine (ECHA), and N,N-dimethylcyclohexylamine (DMCHA). We show that TSSE can desalinate brines with salinities as high as ≈234000 ppm total dissolved solids (i.e., 4.0 M NaCl) and achieve salt removals up to 98.4%. Among the solvents, DIPA exhibited the highest water extraction efficiency whereas ECHA and DMCHA produced water with the lowest salt content and solvent residue content, respectively. Lastly, a high water recovery of >50% was demonstrated for TSSE desalination of 1.5 M NaCl brine using DIPA in semibatch experiments with multiple extraction cycles. This study underscores the unique capabilities of TSSE for the desalination of hypersaline brines
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Membrane-less and Non-Evaporative Desalination of Hypersaline Brines by Temperature Swing Solvent Extraction
Hypersaline brines are of growing environmental importance but are technologically under-served by today’s desalination methods. Temperature swing solvent extraction (TSSE) is a radically different desalination technology that is membrane-less and not based on evaporative phase change. TSSE utilizes low-temperature heat and a low-polarity solvent with temperature-dependent water solubility for the selective extraction of water over salt from saline feeds. This study demonstrates TSSE desalination of high-salinity brines simulated by NaCl solutions with three amine solvents: diisopropylamine (DIPA), N-ethylcyclohexylamine (ECHA), and N,N-dimethylcyclohexylamine (DMCHA). We show that TSSE can desalinate brines with salinities as high as ≈234000 ppm total dissolved solids (i.e., 4.0 M NaCl) and achieve salt removals up to 98.4%. Among the solvents, DIPA exhibited the highest water extraction efficiency whereas ECHA and DMCHA produced water with the lowest salt content and solvent residue content, respectively. Lastly, a high water recovery of >50% was demonstrated for TSSE desalination of 1.5 M NaCl brine using DIPA in semibatch experiments with multiple extraction cycles. This study underscores the unique capabilities of TSSE for the desalination of hypersaline brines
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Phylogenetics, population genetics, molecular epidemiology, and pathogenicity of the Douglas-fir Swiss needle cast pathogen Phaeocryptopus gaeumannii
A hierarchical series of studies, based mainly on molecular data, was conducted to elucidate the life history of the Douglas-fir Swiss needle cast pathogen Phaeocryptopus gaeumannii at macro- and micro-evolutionary scales. This information was then utilized to design and evaluate molecular diagnostic tools for use in studies on the epidemiology of a Swiss needle cast outbreak near Tillamook, Oregon. Phylogenetic analyses of partial nuclear ribosomal gene sequences indicated that P. gaeumannii, currently classified in the Venturiaceae, is closely related to neither Phaeocryptopus nudus, type of the genus, nor Venturia inaequalis, type of the Venturiaceae. Instead, it is closely related to members of the "sooty molds" (Capnodiales), particularly the common and morphologically similar Douglas-fir epiphyte Rasutoria pseudotsugae (Euantennariaceae). Single-strand conformation polymorphisms, revealing DNA sequence variation in five loci, were used to investigate population biology of P. gaeumannii from a worldwide collection of isolates. In western Oregon, P. gaeumannii population structure suggests a predominantly selfing reproductive mode within two reproductively isolated sympatric lineages. One lineage was widely distributed both locally and abroad. The second lineage was restricted to western Oregon and suggested a correlation with symptoms of Swiss needle cast. A novel application of real-time PCR allowed species-specific detection and quantification of P. gaeumannii and proved a good measure of its biomass in Douglas-fir needles. Compared to other techniques (ergosterol and a DNA probe), real-time PCR correlated best with visual estimates of needle colonization and additionally proved useful early in the first year of the colonization process before visible development of fruiting structures. While all four methods provided evidence that sites expressing a range of disease severity differed in the degree of fungal colonization, only real-time PCR consistently separated both moderately and severely diseased sites from relatively healthy sites. Seedling inoculation experiments, fulfilling Koch's postulates, demonstrated that P. gaeumannii is the causal agent of Swiss needle cast, as observed in the Tillamook epidemic. Furthermore, the incorporation of virulence tests provided independent, non-molecular evidence that Oregon's pathogen population is not homogeneous. One strain, isolated from a severely diseased site, caused significantly greater symptom severity than strains derived from less damaged sites
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