Provenance and Paleogeography of the 25-17 Ma Rainbow Gardens Formation: Evidence for Tectonic Activity at Ca. 19 Ma and Internal Drainage rather than Throughgoing Paleorivers on the Southwestern Colorado Plateau

The paleogeographic evolution of the Lake Mead region of southern Nevada and northwest Arizona is crucial to understanding the geologic history of the U.S. Southwest, including the evolution of the Colorado Plateau and formation of the Grand Canyon. The ca. 25–17 Ma Rainbow Gardens Formation in the Lake Mead region, the informally named, roughly coeval Jean Conglomerate, and the ca. 24–19 Ma Buck and Doe Conglomerate southeast of Lake Mead hold the only stratigraphic evidence for the Cenozoic pre-extensional geology and paleogeography of this area. Building on prior work, we present new sedimentologic and stratigraphic data, including sandstone provenance and detrital zircon data, to create a more detailed paleogeographic picture of the Lake Mead, Grand Wash Trough, and Hualapai Plateau region from 25 to 18 Ma. These data confirm that sediment was sourced primarily from Paleozoic strata exposed in surrounding Sevier and Laramide uplifts and active volcanic fields to the north. In addition, a distinctive signal of coarse sediment derived from Proterozoic crystalline basement first appeared in the southwestern corner of the basin ca. 25 Ma at the beginning of Rainbow Gardens Formation deposition and then prograded north and east ca. 19 Ma across the southern half of the basin. Regional thermochronologic data suggest that Cretaceous deposits likely blanketed the Lake Mead region by the end of Sevier thrusting. Post-Laramide northward cliff retreat off the Kingman/Mogollon uplifts left a stepped erosion surface with progressively younger strata preserved northward, on which Rainbow Gardens Formation strata were deposited. Deposition of the Rainbow Gardens Formation in general and the 19 Ma progradational pulse in particular may reflect tectonic uplift events just prior to onset of rapid extension at 17 Ma, as supported by both thermochronology and sedimentary data. Data presented here negate the California and Arizona River hypotheses for an “old” Grand Canyon and also negate models wherein the Rainbow Gardens Formation was the depocenter for a 25–18 Ma Little Colorado paleoriver flowing west through East Kaibab paleocanyons. Instead, provenance and paleocurrent data suggest local to regional sources for deposition of the Rainbow Gardens Formation atop a stripped low-relief western Colorado Plateau surface and preclude any significant input from a regional throughgoing paleoriver entering the basin from the east or northeast

Development of High Fidelity, Fuel-Like Thermal Simulators for Non-Nuclear Testing

Non-nuclear testing can be a valuable tool in development of a space nuclear power or propulsion system. In a non-nuclear test bed, electric heaters are used to simulate the heat from nuclear fuel. Work at the NASA Marshall Space Flight Center seeks to develop high fidelity thermal simulators that not only match the static power profile that would be observed in an operating, fueled nuclear reactor, but to also match the dynamic fuel pin performance during feasible transients. Comparison between the fuel pins and thermal simulators is made at the fuel clad surface, which corresponds to the sheath surface in the thermal simulator. Static and dynamic fuel pin performance was determined using SINDA-FLUINT analysis, and the performance of conceptual thermal simulator designs was compared to the expected nuclear performance. Through a series of iterative analysis, a conceptual high fidelity design will be developed, followed by engineering design, fabrication, and testing to validate the overall design process. Although the resulting thermal simulator will be designed for a specific reactor concept, establishing this rigorous design process will assist in streamlining the thermal simulator development for other reactor concepts

Design of Refractory Metal Heat Pipe Life Test Environment Chamber, Cooling System, and Radio Frequency Heating System

A series of 16 Mo-44.5%Re alloy/sodium heat pipes will be experimentally tested to examine heat pipe aging. To support this evaluation, an environmental test chamber and a number of auxiliary subsystems are required. These subsystems include radio frequency (RF) power supplies/inductive coils, recirculation water coolant loops, and chamber gas conditioning. The heat pipes will be grouped, based on like power and gas mixture requirements, into three clusters of five units each, configured in a pentagonal arrangement. The highest powered heat pipe will be tested separately. Test chamber atmospheric purity is targeted at <0.3 ppb oxygen at an approximate operating pressure of 76 torr (.1.5 psia), maintained by active purification (oxygen level is comparable to a 10(exp -6) torr environment). Treated water will be used in two independent cooling circuits to remove .85 kW. One circuit will service the RF hardware while the other will maintain the heat pipe calorimetry. Initial procedures for the startup and operation of support systems have been identified. Each of these subsystems is outfitted with a variety of instrumentation, integrated with distributed real-time controllers and computers. A local area network provides communication between all devices. This data and control network continuously monitors the health of the test hardware, providing warning indicators followed by automatic shutdown should potentially damaging conditions develop. During hardware construction, a number of checkout tests.many making use of stainless steel prototype heat pipes that are already fabricated.will be required to verify operation

Coletor de macroinvertebrados bentônicos com substrato artificial para monitoramento da qualidade da água em viveiros de produção de tilápia.

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Avaliação preliminar da qualidade da água em duas microbacias do Rio Mogi (SP) .

A expansão da atividade agrícola na bacia hidrográfica do rio Mogi-Guaçu pode causar alguns impactos ambientais graves. Durante o período compreendido entre maio de 2005 e maio de 2006 foram coletadas amostras de água e sedimento para a triagem de organismos bentônicos, visando a sua identificação como bioindicadores. As famílias de macroinvertebrados bentônicos tolerantes à poluição foram encontradas em todos os pontos amostrados, enquanto as famílias sensíveis ficaram restritas a ambientes com pouca influência das áreas agrícolas. O oxigênio dissolvido atingiu sua concentração máxima em um dos pontos de coleta mais preservados do rio Oriçanga. Além disso, os mapas de uso da terra comprovam os dados obtidos referentes aos indicadores de qualidade de água, pois o grau de preservação está diretamente relacionado às culturas agrícolas, às pastagens e às áreas preservadas de mata ciliar.bitstream/CNPMA/7712/1/circular_17.pd

Teachers as leaders in a knowledge society: encouraging signs of a new professionalism

[Abstract]: Challenges confronting schools worldwide are greater than ever,and, likewise, many teachers possess capabilities, talents, and formal credentials more sophisticated than ever. However, the responsibility and authority accorded to teachers have not grown significantly, nor has the image of teaching as a profession advanced significantly. The question becomes, what are the implications for the image and status of the teaching profession as the concept of knowledge society takes a firm hold in the industrialized world? This article addresses the philosophical underpinnings of teacher leadership manifested in case studies where schools sought to achieve the generation of new knowledge as part of a process of whole-school revitalization. Specifically, this article reports on Australian research that has illuminated the work of teacher leaders engaged in the IDEAS project, a joint school revitalization initiative of the University of Southern Queensland and the Queensland Department of Education and the Arts

Developing Public Relations Curricula in Agricultural Communications

Agricultural public relations professionals were surveyed to determine the proficiencies in public relations that they perceive to be most important in an agricultural communications curriculum. They also were asked how frequently they used those proficiencies and how best to integrate the proficiencies in the agricultural communications curriculum. The population for the study consisted of public relations professionals who were members of the Agricultural Relations Council and the Cooperative Communicators Association. Most respondents perceived agricultural proficiencies to be less important than general communications or public relations proficiencies. Proficiencies related to use of the computer skills, human relations skills, time management, writing, and editing were among the most frequently used proficiencies by public relations professionals. Based on these results, it is recommended that university faculty consider focusing public relations curriculum toward writing, editing, presentations, time management, conflict resolution, and teamwork. It also is recommended that students take coursework in agricultural policy and government programs and finance/business principles. Finally, it is recommended that faculty stress the importance of meeting deadlines to prepare students for the public relations profession

Newspaper Coverage of the Bovine Spongiform Encephalopathy Outbreak in the United States: A Content Analysis

Objectivity is a hallmark of good journalism. Objective news writing is particularly important when covering agricultural issues. In this study, researchers used the Hayakawa-Lowry news bias categories to examine the objectivity of news coverage of the bovine spongiform encephalopathy (BSE) outbreak that occurred December 23, 2003, in the United States. The study looked at 149 articles published in USA Today, The Washington Post, and The Seattle Times, dating from the day of the outbreak to February 10, 2004, when the USDA concluded its investigation of the outbreak. Based on the findings, the three newspapers studied were more objective than judgmental in their coverage of the outbreak. Although judgment statements were relatively uncommon, the majority of the judgment statements found were negative toward agriculture. Analysis of the level of objectivity for each newspaper revealed that USA Today was the least objective in its coverage; The Seattle Times was the most objective. This study recommends that reporters be encouraged to include more objective sentences in their writing, that journalism and agricultural communications students be educated about the Hayakawa-Lowry news bias categories, that additional research be conducted on media coverage of other agricultural issues, and that the agricultural literacy level of journalists be examined

Service Learning: A Case Study in an Agricultural Communications Course

Academic service-learning can be an effective and successful educational tool across many disciplines. The benefits afforded students and the community they serve are reciprocal in nature, thereby providing service to the community and capitalizing on a real-world learning environment for the students. Agricultural communications programs can offer for service-learning opportunities within the academic arena. The Campaign Planning for Agricultural and Natural Resources course at Oklahoma State University captures the essence of service-learning and provides students with an opportunity to use knowledge gained in previous courses to develop usable communications campaigns for small businesses or organizations. This case study should serve as a starting point for service-learning research in agricultural communications

Thermal Analysis of Adsorbed Poly(Methyl Methacrylate) on Silica

Modulated differential scanning calorimetry has been used to quantify the glass transitions of small, adsorbed amounts of poly (methyl methacrylate) (PMMA) on silica. While a relatively narrow, single glass transition was found for bulk PMMA, broader two-component transitions were found for the adsorbed polymer. a two-state model based on loosely bound polymer (glass transition similar to bulk) and more tightly bound polymer (glass transition centered around 156°C) was used to interpret the thermograms. on the basis of this model, the amount of tightly bound polymer was found to be approximately 1.3 mg/m 2, corresponding to a 1.1 nm thick layer. the change in heat capacity for the tightly bound polymer at the glass transition temperature was estimated to be about 16% of that of the bulk polymer. © 2006 American Chemical Society