Tectonics of some Amazonian greenstone belts

Greenstone belts exposed amid gneisses, granitoid rocks, and less abundant granulites along the northern and eastern margins of the Amazonian Craton yield Trans-Amazonican metamorphic ages of 2.0-2.1 Ga. Early proterozoic belts in the northern region probably originated as ensimatic island arc complexes. The Archean Carajas belt in the southeastern craton probably formed in an extensional basin on older continental basement. That basement contains older Archean belts with pillow basalts and komatiites. Belts of ultramafic rocks warrant investigatijon as possible ophiolites. A discussion follows

Origin and evolution of the Amazonian craton

The Amazonian craton appears to be formed and modifed by processes much like those of the better-known Precambrian cratons, but the major events did not always follow conventional sequences nor did they occur synchronously with those of other cratons. Much of the craton's Archean style continental crust formation, recorded in granite-greenstone and high-grade terranes, occurred in the Early Proterozoic: a period of relative quiescence in many other Precambrian regions. The common Archean to Proterozoic transition in geological style did not occur here, but an analogous change from abundant marine volcanism to dominantly continental sedimentary and eruptive styles occurred later. Amazonian geology is summarized, explaining the evolution of the craton

Mesospheric scatter and its microstructure

The difference in character between mesospheric returns from about 70 and about 80 km was noted. The 69-km echo is characterized by a single return with about .1 Hz width, while the 82.5 km return extends over more than 3 Hz bandwidth; this difference is also perceptible, but to a lesser degree, on the fading curves. The conclusion seems inescapable that internal random velocities of a few m/s are present within the scattering volume for the 82.5-km echo. The most likely source for these rather large velocities is convective instability arising from deformations of the temperature profile by breaking gravity waves. The distinction between the two types of scatter at these altitudes probably accounts for the behavior with frequency of the nightime fading period at low and very low frequencies. The fading period of D-region reflections at night was constant at about 7 min from 16 to 43 kHz, but that at frequencies of 70 kHz and above, the fading period decreased in such a way as to indicate the presence of irregularities smaller than about 1 km in size. This suggests that frequencies of 48 kHz and above, the fading period decreased in such a way as to indicate the presence of irregularities smaller than about 1 km in size. This suggests that frequencies of 48 kHz and below were reflected primarily from the region below 80 km where the narrow spectral irregularities dominate

H2S paper strip method - A bacteriological test for faecal coliforms in drinking water at various temperatures

Epidemics arising from waterborne diseases are a global health problem. Faecal contamination of drinking water is the main cause of these outbreaks. According to WHO (1996) for drinking water to be safe, a 100 ml sample should not contain any coliform bacteria. The standard methods currently used for routine testing have many limitations especially when applied in remote areas. The H2S method has been developed as an on-site, inexpensive and easy to use method to test drinking water for remote and rural areas. The present work analyses the reliability of the H2S method for detecting faecal contamination in drinking water. The minimum level of faecal coliforms that could be detected and the incubation period required at various levels of contamination were studied. The range of temperatures at which the method was effective and the incubation period required at various temperatures were also determined. The H2S method was found to be able to detect contamination down to a level of 1 CFU/100 ml of coliform bacteria. Although the H2S method could be used at a temperature range of 20 to 44oC, temperatures between 28 to 37oC gave faster results. An incubation period of only 24 hours was required at 37oC, which was found to be the most suitable incubation temperature. The incubation period increased with a decrease or increase in temperature

Exploring the notion of quality in quality higher education assessment in a collaborative future

The purpose of this paper is to contribute to the debate on the notion of quality in higher education with particular focus on ‘objectifying through articulation’ the assessment of quality by professional experts. The paper gives an overview of the differentiations of quality as used in higher education. It explores a substantial piece of evaluation research which was carried out between 2009 and 2011 by the authors at the Institute for Work Based Learning at Middlesex University

Self-beating instabilities in bistable devices

Since the observation of optical bistability by Gibbs et al., optical bistability has been the field where researchers from many fields have found a common place to work. More recently, when Ikeda and co-workers discussed the effect of a delayed feedback on instability of a ring cavity containing a non linear dielectric medium, and pointed out that the transmitted light from the ring cavity can be periodic or chaotic in time under a certain condition, optical bistable devices have shown new possibilities to be applied in many different fields. The novel phenomenon has been predicted to be observed in the hybrid optical device and has been confirmed by Gibbs et al. Moreover, as we have shown, a similar effect can be obtained when liquid crystal cells are employed as non linear element

MP763: Without Benefit of Insects: The Story of Edith M. Patch of the University of Maine

A biography of noted entomologist Edith M. Patch, focusing on her time and research at the University of Mainehttps://digitalcommons.library.umaine.edu/aes_miscpubs/1037/thumbnail.jp

Musical Expression on Wind Instruments: Perspectives from a Panel of Experts

Musical expression, or a performer’s interpretation of the aesthetic message intended by the composer, involves thoughtful manipulation of perceptual variables such as dynamics, tempo, articulation, and timbre. Musical expression is commonly associated with artistry and achievement in music, yet research on pedagogy for teaching musical expression to wind instrumentalists is limited. The purpose of this study is to use perspectives from professional wind instrumentalists and conductors to explore how musical expression on wind instruments is demonstrated and measured. The qualitative tradition of the Delphi method, with three rounds of data collection, provided the structure for answering the research questions. The importance of effectively communicating musical interpretation through performance was a recurring theme within the data collection as well as the literature review. Findings suggest that a performer’s abilities both to appropriately analyze the music and then to successfully communicate his or her interpretation of the music to a listener are critical for achieving artistry in musical expression. The study may provide valuable insight for a deeper understanding of pedagogical strategies needed for teaching musical expression to wind instrumentalists