Investigation of DC-8 nacelle modifications to reduce fan-compressor noise in airport communities. Part 4 - Flight acoustical and performance evaluations, for period May 1967 - October 1969

Flight acoustical and performance evaluations of DC 8 nacelle modifications to reduce fan-compressor noise in airport communitie

Molecular dynamics simulations of lead clusters

Molecular dynamics simulations of nanometer-sized lead clusters have been performed using the Lim, Ong and Ercolessi glue potential (Surf. Sci. {\bf 269/270}, 1109 (1992)). The binding energies of clusters forming crystalline (fcc), decahedron and icosahedron structures are compared, showing that fcc cuboctahedra are the most energetically favoured of these polyhedral model structures. However, simulations of the freezing of liquid droplets produced a characteristic form of ``shaved'' icosahedron, in which atoms are absent at the edges and apexes of the polyhedron. This arrangement is energetically favoured for 600-4000 atom clusters. Larger clusters favour crystalline structures. Indeed, simulated freezing of a 6525-atom liquid droplet produced an imperfect fcc Wulff particle, containing a number of parallel stacking faults. The effects of temperature on the preferred structure of crystalline clusters below the melting point have been considered. The implications of these results for the interpretation of experimental data is discussed.Comment: 11 pages, 18 figues, new section added and one figure added, other minor changes for publicatio

Kidney cell electrophoresis in space flight: Rationale, methods, results and flow cytometry applications

Cultures of human embryonic kidney cells consistently contain an electrophoretically separable subpopulation of cells that produce high levels of urokinase and have an electrophoretic mobility about 85 percent as high as that of the most mobile human embryonic kidney cells. This subpopulation is rich in large epithelioid cells that have relatively little internal structure. When resolution and throughput are adequate, free fluid electrophoresis can be used to isolate a broad band of low mobility cells which also produces high levels of plasminogen activators (PAs). In the course of performing this, it was discovered that all electrophoretic subpopulations of cultured human embryonic kidney cells produce some PAs and that separate subpopulations produce high quantities of different types of PA's. This information and the development of sensitive assays for this project have provided new insights into cell secretion mechanisms related to fibrinolysis. These advances would probably not have been made without the NASA program to explore fundamental questions of free fluid electrophoresis in space

Evaluation of peak-picking algorithms for protein mass spectrometry

Peak picking is an early key step in MS data analysis. We compare three commonly used approaches to peak picking and discuss their merits by means of statistical analysis. Methods investigated encompass signal-to-noise ratio, continuous wavelet transform, and a correlation-based approach using a Gaussian template. Functionality of the three methods is illustrated and discussed in a practical context using a mass spectral data set created with MALDI-TOF technology. Sensitivity and specificity are investigated using a manually defined reference set of peaks. As an additional criterion, the robustness of the three methods is assessed by a perturbation analysis and illustrated using ROC curves

Unexpected Changes in Soil Phosphorus Dynamics Along Pasture Chronosequences in the Humid Tropics

Phosphorus (P) is widely believed to limit plant growth and organic matter storage in a large fraction of the world\u27s lowland tropical rain forests. We investigated how the most common land use change in such forests, conversion to cattle pasture, affects soil P fractions along pasture chronosequences in the central Brazilian Amazon and in southwestern Costa Rica. Our sites represent a broad range in rainfall, soil type, management strategies, and total soil P (45.2–1228.0 μg P/g soil), yet we found some unexpected and at times quite similar changes in soil P in all sites. In the Brazilian sites, where rainfall is relatively low and pasture management is more intense than in the Costa Rican sites, significant losses in total soil P and soil organic carbon (SOC) were seen with pasture age on already P-deficient Oxisol and Entisol soils. However, P losses were from inorganic soil P fractions, while organic forms of soil P remained constant or increased with pasture age, despite the declines in SOC. In Costa Rica, SOC remained constant across the Oxisol sites and increased from forest to pasture on the Mollisols, while soil organic P increased with pasture age in both sequences

Support for graphicacy: a review of textbooks available to accounting students

This Teaching Note reports on the support available in textbooks for graphicacy that will help students understand the complexities of graphical displays. Graphical displays play a significant role in financial reporting, and studies have found evidence of measurement distortion and selection bias. To understand the complexities of graphical displays, students need a sound understanding of graphicacy and support from the textbooks available to them to develop that understanding. The Teaching Note reports on a survey that examined the textbooks available to students attending two Scottish universities. The support of critical graphicacy skills was examined in conjunction with textbook characteristics. The survey, which was not restricted to textbooks designated as required reading, examined the textbooks for content on data measurement and graphical displays. The findings highlight a lack of support for graphicacy in the textbooks selected. The study concludes that accounting educators need to scrutinize more closely the selection of textbooks and calls for more extensive research into textbooks as a pedagogic tool

Ashland community survey : an economic, social and sanitary survey in Howard County, Missouri

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Assessment of Keratitis Damage in an Age Dependent Mouse Model Using Analytical Software

Background: Streptococcus pneumoniae (pneumococcus) is a grampositive bacterium that is responsible for diseases such as, otitis media, conjunctivitis, bacterial keratitis, pneumonia, and meningitis. Bacterial keratitis is one of the most common after-effects of trauma to the eye. Some reports have shown the S. pneumoniae spreads through enzymes that are produced to digest the cornea, which in turn can causes blindness. There is a need for more improved measures that can reverse the detrimental effects of the bacteria. The long-term goal of this research is to better understand the complete role of S. pneumoniae and its components in bacterial keratitis to develop next generation therapies to prevent blindness. The purpose of this study is to develop alternative measures to evaluate damage associated with keratitis infection by use of computer applications. Methods: This study analyzed images of the established Keratitis pneumococcal mouse model. The eye images of mice 7-8-week-old and 9-month-old were collected. Additional images were taken on post-infection days one, three, five, and nine, revealing the progression of the infection. Results: The ImageJ Application provided more in depth review to determine the detrimental effects of S. pneumoniae. Through the software, a “Color Threshold” was created on every image to emphasize the area of damage caused by the bacteria. A scatter plot of every image created a map of the particles, and the diameter created a scale demonstrating the impact of keratitis. Data revealed that the most significant increase in infection occurs between Day 1 and 3 post-infection. Conclusions: The study has created a computer model to establish a baseline for the infection process of S. pneumoniae in the traditional mouse model. ImageJ has proven to be a useful tool to analyze the impact of disease on the murine model. Results from this study also provide evidence of the importance of early intervention in ocular disease

Entropic effects on the Size Evolution of Cluster Structure

We show that the vibrational entropy can play a crucial role in determining the equilibrium structure of clusters by constructing structural phase diagrams showing how the structure depends upon both size and temperature. These phase diagrams are obtained for example rare gas and metal clusters.Comment: 5 pages, 3 figure