System testing of a production Ada (trademark) project: The GRODY study

The use of the Ada language and design methodologies that utilize its features has a strong impact on all phases of the software development project lifecycle. At the National Aeronautics and Space Administration/Goddard Space Flight Center (NASA/GSFC), the Software Engineering Laboratory (SEL) conducted an experiment in parallel development of two flight dynamics systems in FORTRAN and Ada. The teams found some qualitative differences between the system test phases of the two projects. Although planning for system testing and conducting of tests were not generally affected by the use of Ada, the solving of problems found in system testing was generally facilitated by Ada constructs and design methodology. Most problems found in system testing were not due to difficulty with the language or methodology but to lack of experience with the application

An Excel-Aided Method For Teaching Calculus-Based Business Mathematics

Calculus-based business mathematics is a required quantitative course for undergraduate business students in most AACSB accredited schools or colleges of business. Many business students, however, have relatively weak mathematical background or even display math-phobia when presented with calculus problems. Because of the popularity of Excel, its ease of learning, and its rich computational functions, we have been teaching our calculus-based business mathematics in computer labs and accumulating feasible experience in employing Excel to assist our students’ learning in this course. In this paper we illustrate how to use Excel to enhance students’ understanding in difficult and important calculus-based mathematical principles and to find numerical solutions to difficult quantitative business problems by providing them with heuristic examples. Our experience shows that Excel can greatly simplify the interpretation of pure calculus principles and can substantially reduce students’ misunderstanding in applying calculus principles in solving quantitative business problems

Seismic Soil Structure Interaction Analyses of an Office Building in Oakland, California

This paper discusses soil-structure interaction (SSI) analyses for a 10-story office building with three levels of basement (10 meters) located in downtown Oakland, California. The objectives of these analyses were to assess the effects of SSI on the response of the building and to develop ground-level input earthquake motions at the base of the building for use by the project structural engineer. The SSI analyses were conducted using the two-dimensional finite element program FLUSH. The results of these analyses indicate that SSI has a negligible effect on horizontal ground motions at and near the building’s predominant period (T ~ 1.8 seconds). Minor but unfavorable SSI effects were found at higher frequencies. The effects of SSI on the vertical motions in the building were for practical purposes, negligible. Parametric studies indicate that more favorable SSI effects may have been realized if the building was surrounded by softer soils

Rare Earth Elements Purification using Ligand-Assisted Displacement Chromatography

Rare Earth Elements (REEs) including the lanthanide series, Yttrium, and Scandium play a critical and essential role in various industries such as electronics, power, and defense. Traditional methods have difficulties in separating REEs due to their high similarities in chemical and physical properties. With increasing demand of REEs, current industrial techniques of REE extractions, two phase liquid-liquid extraction, are not efficient enough to meet the market’s need without causing serious environmental problems. Specifically, two phase liquid-liquid extraction uses a large number of mixer-settler units in series and parallel for purification of REEs. This method consumes excessive solvents and chemicals that are environmentally hazardous. Spedding and Powell studied ligand-assisted displacement chromatography of REE recovery in 1950’s, which showed high yields and high purity but low productivity. Their process was designed based on trials and errors and was not optimized. The first goal of this study is to develop and test a systematic design and optimization method to increase sorbent productivity and reduce separation cost. The second goal is to understand the dynamic separation mechanism using rate model simulations. We tested the design method experimentally using three REEs, Nd, Sm and Pr. Ammonium citrate was used as a ligand displacer. Frontal tests were used to estimate the various parameters corresponding to adsorption, reaction and mass transfer. Rate model simulations were conducted to verify experimental data. The experimental design aimed to achieve an average yield of each product of 97% with a purity of 99%, and sorbent productivity an order of magnitude higher than that of Spedding and Powell

Characterization of microRNA expression profiles in normal human tissues

<p>Abstract</p> <p>Background</p> <p>Measuring the quantity of miRNAs in tissues of different physiological and pathological conditions is an important first step to investigate the functions of miRNAs. Matched samples from normal state can provide essential baseline references to analyze the variation of miRNA abundance.</p> <p>Results</p> <p>We provided expression data of 345 miRNAs in 40 normal human tissues, which identified universally expressed miRNAs, and several groups of miRNAs expressed exclusively or preferentially in certain tissue types. Many miRNAs with co-regulated expression patterns are located within the same genomic clusters, and candidate transcriptional factors that control the pattern of their expression may be identified by a comparative genomic strategy. Hierarchical clustering of normal tissues by their miRNA expression profiles basically followed the structure, anatomical locations, and physiological functions of the organs, suggesting that functions of a miRNA could be appreciated by linking to the biologies of the tissues in which it is uniquely expressed. Many predicted target genes of miRNAs that had specific reduced expression in brain and peripheral blood mononuclear cells are required for embryonic development of the nervous and hematopoietic systems based on database search.</p> <p>Conclusion</p> <p>We presented a global view of tissue distribution of miRNAs in relation to their chromosomal locations and genomic structures. We also described evidence from the <it>cis</it>-regulatory elements and the predicted target genes of miRNAs to support their tissue-specific functional roles to regulate the physiologies of the normal tissues in which they are expressed.</p

Cartilage-specific ablation of site-1 protease in mice results in the endoplasmic reticulum entrapment of type IIB procollagen and down-regulation of cholesterol and lipid homeostasis

The proprotein convertase site-1 protease (S1P) converts latent ER-membrane bound transcription factors SREBPs and ATF6 to their active forms. SREBPs are involved in cholesterol and fatty acid homeostasis whereas ATF6 is involved in unfolded protein response pathways (UPR). Cartilage-specific ablation of S1P in mice (S1Pcko) results in abnormal cartilage devoid of type II collagen protein (Col II). S1Pcko mice also lack endochondral bone development. To analyze S1Pcko cartilage we performed double-labeled immunofluorescence studies for matrix proteins that demonstrated that type IIB procollagen is trapped inside the ER in S1Pcko chondrocytes. This retention is specific to type IIB procollagen; other cartilage proteins such as type IIA procollagen, cartilage oligomeric matrix protein (COMP) and aggrecan are not affected. The S1Pcko cartilage thus exhibits COMP-, aggrecan-, and type IIA procollagen-derived matrices but is characterized by the absence of a type IIB procollagen-derived matrix. To understand the molecular reason behind S1Pcko phenotypes we performed genome-wide transcriptional profiling of cartilage isolated from S1Pcko and wild type littermates. While the UPR pathways are unaffected, the SREBPs-directed cholesterol and fatty acid pathways are significantly down-regulated in S1Pcko chondrocytes, with maximal down-regulation of the stearoyl-CoA desaturase-1 (Scd1) gene. However, mouse models that lack Scd1 or exhibit reduction in lipid homeostasis do not suffer from the ER retention of Col II or lack endochondral bone. These studies indicate an indispensable role for S1P in type IIB procollagen trafficking from the ER. This role appears not to be related to lipid pathways or other current known functions of S1P and is likely dependent on additional, yet unknown, S1P substrates in chondrocytes