8,896 research outputs found
Growth in reading and how children spend their time outside of school
Running title: Growth in readingIncludes bibliographical references (leaves 36-38)Performed pursuant to contract no. 400-81-0030 of the National Institute of Educatio
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Biodegradation of aromatic compounds by high latitude phytoplankton
"It was the purpose of the work undertaken to bring into pure culture representative diatoms from the Cook Inlet and the ice-edge in the Bering Sea and to examine their capacity for the oxidation of aromatic compounds using naphthalene as a model substrate. Three diatoms from the Cook Inlet (Kasitsna Bay) were shown to metabolize naphthalene at 6 or 12Ā°C to 1-naphthol and other unidentified ethyl acetate and water-soluble products. Likewise, three diatoms isolated from samples collected at the ice-edge in the Bering Sea also formed small amounts of 1-naphthol from naphthalene when incubated in the light at 0 or 10Ā°C. We have not been able to rigorously prove that any algal cell, be it a blue-green alga, a green alga, or a diatom can metabolize (1-Ā¹ā“C) naphthalene far enough to produce Ā¹ā“COā. However, if we assume a stoichiometery of one 1-naphthol in the algae equivalent to one COā in bacteria, then for mesophilic algae, the rate of 1-naphthol production is roughly estimated as 10% of the in situ marine potential, and perhaps higher if only the photic zone is considered. We have as yet, no corresponding values for rate of 1-naphthol formation from naphthalene by cold-adapted or psychrophilic diatom cultures, however, it seems reasonable to suggest that algal aromatic transformations may also be a significant fraction of bacterial activity in cold environments. In addition to studies on the oxidation of naphthalene we have also examined the sensitivity of the Bering Sea psychrophilic diatoms to crude oil samples from Cook Inlet and Prudhoe Bay. The results with pure cultures indicate that the toxicity of crude oil was enhanced in psychrophilic diatoms growing at OĀ°C or 10Ā°C as compared to previous studies with mesophilic forms. There are several important consequences of the results for Alaskan OCS oil and gas development. It is now clear that pure cultures of diatoms isolated from either the lower Cook Inlet or from the ice-edge in the Bering Sea can oxidize aromatic compounds such as naphthalene. Whether the metabolites persist through the food chain and will be more or less toxic than naphthalene itself is not known. The results with naphthalene also imply that the photic zone can be an important sink for aromatic hydrocarbon transformations. There are certainly differences among microalgae in the capacity to oxidize naphthalene. It seems prudent, therefore, to insure, via monitoring, that accidental introduction of aromatic compounds in Alaskan waters does not cause a selective or enrichment effect on existing phytoplankton populations. A second area of environmental concern is the suggestion of an enhanced crude oil toxicity in slower growing psychrophilic diatoms as compared to their mesophilic cousins. Crude oil spills near or under the sea ice may severely impact primary productivity, and thereby higher tropic level.Final report RD/MPF24-Effects-675April 30, 1982Marine Scienc
Leadership Development And Support: The Perceived Effects Of A Dialogic Peer Coaching Program
This formative program evaluation examined the perceptions of school-based leaders in a peer dialogic group coaching and discussion program in a larger school district in Western Canada. The pilot program included 14 principals and vice-principals from 12 different elementary or high schools who participated in either a discussion or coaching format to support and develop leadership and communication skills in six biweekly meetings over three months. Qualitative inductive content analysis was used to code and theme the data that resulted from semi-structured interviews and anonymous online surveys. Four main themes emerged from the data, and these themes described key elements of the coaching and discussion program that participants found important to program success. The first themes is Setting the Stage, which alludes to preconditions participants identified as critical to program success. The second is Shared Presence, which described the ways participants showed up to coaching or group discussions and how individuals contributed to group development. The third is Living the Learning, which explores the ways that participants perceived the structures that framed growth and support and how people participated in those structures. The fourth is The Value of Partnership, which describes the effects of the program for both individuals and the school district. This study found that participants perceived numerous elements that deserve careful consideration for program improvement or continuation. The emerging model for the program was an interconnected web of elements, each deserving of attention and important to program success. Whereas the nature of a formative assessment does not provide generalizability or transferability, this study contends that leadership program developers could benefit from a deep knowledge of program elements and an open discussion of expectations and structures going into a school-based administrator leadership and communication development and support program. Key elements include the use of a robust coaching model, having an expert resource, making the program optional and ensuring that the meetings are participant-driven
The Effects of Trumpet Construction on Literature from Antiquity through the Classical Period
A trumpetās construction is fundamental to its distinct tone color. Over a period of centuries, this tone color and its resonant qualities have changed as the trumpetās construction has changed. These changes are also reflected in the purpose and function of the instrument in society, as well as in the actual music written for it. While the design of the B-flat trumpet as it is known today was not finalized until the mid-20th century, some of the most progressive changes in trumpet construction and literature have occurred between the first known iterations of the instrument during antiquity and what is known as the Classical period of Western art music during the Common Practice Era. The best understanding of the historical path of the trumpet and its idiomatic literature will be gleaned from a chronological approach. Therefore, an examination must first be made of the earliest trumpets, their purposes in the ancient world through the Middle Ages, and some of the most characteristic musical works of those periods. Next, the evolution of the trumpet during the Renaissance will be explored, followed by the Baroque period. Finally, the composers of the Classical period will offer their own insights about the purpose of the trumpet and its place in the musical realm. The advancements in the construction of the trumpet have had a profound impact on the parallel advancements of Western trumpet literature from antiquity through the Classical period. Despite their name, brass instruments are not classified with respect to the raw material
Criticality and isostaticity in fiber networks
The rigidity of elastic networks depends sensitively on their internal
connectivity and the nature of the interactions between constituents. Particles
interacting via central forces undergo a zero-temperature rigidity-percolation
transition near the isostatic threshold, where the constraints and internal
degrees of freedom are equal in number. Fibrous networks, such as those that
form the cellular cytoskeleton, become rigid at a lower threshold due to
additional bending constraints. However, the degree to which bending governs
network mechanics remains a subject of considerable debate. We study disordered
fibrous networks with variable coordination number, both above and below the
central-force isostatic point. This point controls a broad crossover from
stretching- to bending-dominated elasticity. Strikingly, this crossover
exhibits an anomalous power-law dependence of the shear modulus on both
stretching and bending rigidities. At the central-force isostatic point---well
above the rigidity threshold---we find divergent strain fluctuations together
with a divergent correlation length , implying a breakdown of continuum
elasticity in this simple mechanical system on length scales less than .Comment: 6 pages, 5 figure
Morphological and Behavioral Traits Associated with Locomotion in Lizards
Morphology, locomotion, and behavior are co-adapted to optimize performance and ultimately fitness. Successfully navigating a complex environment is dictated by an animalās locomotor behavior, and for some behaviors, its locomotor performance. The locomotor performance of an organism is directly related to the form and function of the structures involved in locomotion such that movement is efficient ā that is, minimal loss of energy. The first chapter of this thesis focuses on the effects of obstacle placement and forelimb position on facultative bipedalism. Placing an obstacle beyond a lizardās acceleration threshold did not affect the frequency of bipedal posture. Furthermore, the forelimb position of streamlined species is stereotyped during bipedal running, whereas the forelimb positions are varied in short stocky species. The second chapter investigates shape variation in the scapula among Phrynosomatid lizards across a gradient of species that vary in the use of horizontal to vertical locomotor planes. I determined that while global scapula shape is relatively conserved among lizards, localized changes occur at the muscle attachment sites used in vertical vs. horizontal locomotion. Furthermore, scapular shape in relation to habitat use is phylogenetically conserved with the exception of some Sceloporus species which diverged independently towards terrestrial locomotion
Hispanic Migration to Northeastern Colorado During the Nineteen Twenties: Influences of Sugar Beet Agriculture
Growing beets to process into sugar was a large and important industry in 1920s Northeastern CO. The infrastructure to support the sugar beet industry was built and expanded in the first decades of the 1900s. Beyond infrastructure requirements the sugar beet industry relied on seasonal low skilled field labor. The migration and settlement patterns of sugar beet laborers in the 1920s to Northeastern Colorado were influenced by the actions of the Great Western Sugar Company. In 1909, German-Russian immigrants were the dominant demographic working the beet fields in Northeastern CO but by 1927 that trend shifted overwhelmingly to families of Mexican and Mexican American heritage. These Hispanic families came from the Southwestern US as well as Mexico and primarily spent the summer living at the beet fields. During the winter some laborers returned to the Southwest or Mexico, others lived in poor areas of Denver, and others still lived on the outskirts of Northeastern Colorado towns. In Fort Collins, Greeley and other Northeastern Colorado towns, the Great Western Sugar Company subsidized housing for select Hispanic beet labor families. This thesis advances understanding of Colorado history as it relates to early Hispanic migration and offers a case study in migration forces. While social networks are important to patterns of labor movement, the recruitment efforts and housing initiatives of the Great Western Sugar Company were highly influential
Microfluidics for environmental analysis
2018 Summer.Includes bibliographical references.During my graduate dissertation work I designed and utilized microfluidic devices to study, model, and assess environmental systems. Investigation of environmental systems is important for areas of industry, agriculture, and human health. While effective and well-established, traditional methods to perform environmental assessment typically involve instrumentation that is expensive and has limited portability. Because of this, analysis of environmental systems can have considerable financial burden and be limited to laboratory settings. To overcome the limitations of traditional methods researchers have turned to microfluidic devices to perform environmental analyses. Microfluidics function as a versatile, inexpensive, and rapidly prototyped analytical tool that can achieve analysis in field setting with limited infrastructure; furthermore, microfluidic devices can also be used to study fundamental chemistry or model complex environmental systems. Given the advantages of microfluidic devices, the research presented herein was accomplished using this alternative to traditional instrumentation. The research projects described in this dissertation involve: 1) the study of fundamental chemistry associated with surfactant surface fouling facilitated by divalent metal cations; 2) the creation of a microfluidic device to study fluid interactions within an oil reservoir; and 3) the fabrication of a paper-based microfluidic to selectively quantify K+ in complex samples. The first research topic discussed involves observation of dynamic evidence that supports the hypothesized cation bridging phenomenon. Experimental results were acquired by pairing traditional microfluidics with the current monitoring method to observe relative changes to a charged surface's zeta potential. Divalent metal cations were found to increase surfactant adsorption, and cations of increasing charge density were found to have a greater effect on surface charge. Analysis of the experimental data further supports theoretical cation bridging models and expands on knowledge relating to the mechanism by which surfactant adsorption occurs. This work was published in the ACS journal Langmuir (2018, 34 (4), pp 1550ā1556). The second project discussed herein focuses on the development of the microfluidic Flow On Rock Device (FORD) that was designed to study fluid interactions within complex media. The FORD was designed to be an alternative to existing fluid modeling methods and microfluidic devices that test oil recovery strategies. Fabrication of the FORD was accomplished by incorporating real reservoir rock core samples into the device. The novelty of this device is due to the simplicity and accuracy by which the physical and chemical characteristics are represented. This project has been accepted for publication pending minor revisions in Microfluidics and Nanofluidics. The final project discussed the creation of the first non-electrochemical microfluidic paper-based analytical device (ĀµPAD) capable of quantitatively measuring alkali or alkaline earth metals using K+ as a model analyte. This device was fabricated by combining distance-based analytical quantification in ĀµPADs with optode nanosensors. Experimental results were obtained using the naked eye without the requirement of a power source or external hardware. The resulting distance-based ĀµPAD showed high selectivity and the capacity to quantify K+ in real undiluted human serum samples. This work has been published in the ACS journal Analytical Chemistry (2018, 90 (7), pp 4894ā4900). The research projects briefly described above and thoroughly discussed later within this dissertation were made possible by the utilization of microfluidic devices. These projects investigated various aspects of environmental chemistry without the use of traditional instrumentation or methods. The experimental results that were obtained further the fundamental understanding of surfactant adsorption, provide an inexpensive and accurate model to observe fluid interactions within reservoir rock material, and allow for the selective quantification of K+ in a paper-based device without the use of a power source. The funding for each of these projects was supplied by BP plc and Global Good, as is mentioned accordingly within this dissertation
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