Geometric constraints within feature hierarchies

We study the problem of enabling general 2D and 3D variational constraint representation to be used in conjunction with a feature hierarchy representation, where some of the features may use procedural or other non-constraint based representations. We trace the challenge to a requirement on constraint decomposition algorithms or decomposition-recombination (DR) planners used by most variational constraint solvers, formalize the feature hierarchy incorporation problem for DR-planners, clarify its relationship to other problems, and provide an efficient algorithmic solution. The new algorithms have been implemented in the general, 2D and 3D opensource geometric constraint solver FRONTIER developed at the University of Florida.     

Project management using microcomputers

This paper examines microcomputer applications in managing projects. It is written at an introductory level, primarily intended for project managers and schedulers who are considering using a microcomputer based system. It reviews the current status of software, provides examples of use, and implementation considerations.     

Synergistic enhancement of mechanical,viscoelastic, transport,thermal, and radiation aging characteristics through chemically bonded interface in nanosilica reinforced EPDM-CIIR blends

The study investigates the influence of bis(3-triethoxysilylpropyl)tetrasulfide (TESPT) grafted nanosilica (NS) reinforcement on the mechanical, viscoelastic, thermal, and transport characteristics as well as behavior after exposure to different cumulative γ-radiation doses of EPDM-CIIR blends for application in nuclear and hydrocarbon environments. The tensile strength and modulus of the nanocomposites were enhanced upto 64% and 118%, respectively whereas solvent diffusion coefficient reduced by 22%. The degradation onset temperature improved from 485°C for unfilled blends to 503°C for the nanocomposites. γ-radiation aging resistance of EPDM-CIIR blends improved with incorporation of nanosilica, with blends containing 7.5phrNS showing optimum properties and radiation aging resistance. The property improvements are attributed to the dispersion of NS and chemically interfaced covalent linkages between SiO₂-EPDM/CIIR chains that provides large interfacial area for effective stress transfer and creates barrier to free radical and solvent permeation. The applicability of Korsmeyer-Peppas, Peppas-Sahlin, and Higuchi models to predict of sorption behavior are investigated. Coats-Redfern and Horowitz-Metzger models were employed to evaluate the activation energy for thermal degradation. Slight decline in properties at higher nanofiller contents was due to the formation of agglomerates. TEM, FTIR, and rheological curves were utilized to corroborate these observations. FTIR and ESR analysis provided insight on the chemical changes in the nanocomposites after irradiation.     

Sampling efficiencies of two modified viable cascade impactors

Prevention of airborne contagious diseases depends on successful characterization of aerosols in the environment. The use of cascade impactors to characterize ambient aerosols is one of the most commonly used methods, providing data on both particle size and concentration. In this study, the use of a cascade impactor recently described in the literature using 8 mL of liquid in Petri dishes (CI-L) was compared with a new method that uses wet membrane filters on top of wax filled Petri dishes (CI-WWMF). Sampling efficiencies of the cascade impactors were evaluated using 0.5, 1, 3, and 5 μm polystyrene latex (PSL) microspheres and aerosol consisting of single spores of Bacillus atrophaeus var. globigii (BG). The sampling efficiency of the CI-L was 6%, 11%, 17%, 21%, and 58% for 0.5, 1, 3, 5 μm PSL microspheres and BG spores, respectively. Higher overall sampling efficiencies of 71%, 91%, 60%, 64%, and 104% were observed for the same size and type of particles for the CI-WWMF. This study indicates that using wet filters on top of wax-filled Petri dishes (CI-WWMF) in a viable cascade impactor is more efficient than the CI-L method for size-selectively collecting biological aerosols from the environment. The CI-WWMF method is useful when a liquid medium is required for identifying and quantifying organisms using polymerase chain reaction (PCR) and immuno-assay techniques.

Copyright © 2017 American Association for Aerosol Research     

Elevated expression levels of ANXA11, integrins β3 and α3, and TNF-α contribute to a candidate proteomic signature in urine for kidney allograft rejection

Purpose: Kidney transplantation is the treatment of choice for end stage renal disease, with long-term allograft loss being the major obstacle, and for which potential treatments are based on a histological diagnosis. The problem is that markers for predicting graft rejection are limited in number, are invasive, and are quite non-specific. We have hypothesized that protein biomarkers might be discovered in the urine of patients when acute or chronic rejection might be occurring. Experimental design: We have established a workflow in which initial screening for candidate biomarkers is first performed using urine samples on large-scale antibody microarrays. This approach generated several dozen candidates. The next step is to qualify some of the strongest signals using the high-throughput Reverse Capture Protein Microarray platform. Results: Four top candidates including ANXA11, Integrin α3, Integrin β3 and TNF-α, initially identified by the antibody microarray platform, were all qualified using Reverse Capture Protein Microarrays. We also used receiver operating condition (ROC) curves to independently quantify the specificity and sensitivity of these four analytes. Conclusions and clinical relevance: The present data suggest that these novel four analytes in the urine, together or independently, may contribute to a robust and quantitative urine proteomic signature for diagnosing acute or chronic rejection of renal allografts.     

“My child will be respected”: Parental perspectives on computers and education in Rural India

Public spending on computer centers in rural Indian public schools raise questions about the value of expensive modern technology in extremely resource-strapped environments. Arguments for or against providing computers in low-income schools have appeared in policy circles, academia, teacher conferences, and philanthropic discussions, with passionate rhetoric from all sides. We present the results of a qualitative study of computer-aided learning centers in schools catering primarily to Below Poverty Line (BPL) families in four districts of rural Karnataka, South India. Here, we held a series of open-and close-ended discussions with parents of children from these schools on issues such as aspirations, quality of schooling, and the perception of computers more generally. The research reveals a range of voices on hopes for the next generation, perceived value of computer courses and higher education, and the perceived changes in villages after the arrival of computers in their local schools. It emerges that for many parents, the computer has an immense symbolic value—separate from its functional value—that is tied to social and economic ascendancy. We find that this symbolic value derives from associations that parents imbibe from their various interactions with people using computers in a range of situations. We find in our interviews a heightened sense of mystique over the technology and its potential, across people with varying levels of first-hand experience and understanding of computers. We find that notions of change and hope are situated within an environment of great fear about the future of agriculture. We argue here that this, alongside a widespread existing discourse about computers in media and public life in India, mostly emerging from urban middle-classes ideas around technology, help spur a strong sense of expectation that the computers can dramatically change social prospects even among the poorest and most excluded. From competing with English as the gateway to power, to impacting dowry costs for female youth, interviews show a myriad of expectations from technology, creating what we see as a strong case for a nuanced look at the discourse and mythology of computers and technology in developing regions.

Structural and thermal studies on Na2U(MoO4)3 and Na4U(MoO4)4

In Na–U(IV)–Mo–O system, two quaternary compounds Na₂U(MoO₄)₃ and Na₄U(MoO₄)₄ were prepared by solid state reactions of Na₂MoO₄, UMoO₅ and MoO₃ in the required stoichiometric ratio at 500 °C in evacuated sealed quartz ampoules. The crystal structure of both the compounds were derived from X-ray powder diffraction data in the tetragonal system by Rietveld profile method. Na₂U(MoO₄)₃ has scheelite structure, whereas Na₄U(MoO₄)₄ has scheelite superlattice structure.

TG curves of Na₂U(MoO₄)₃ and Na₄U(MoO₄)₄ did not show any significant weight change up to 750 °C in an inert atmosphere. During the heating cycle in an inert atmosphere, DTA curves of Na₂U(MoO₄)₃ and Na₄U(MoO₄)₄ showed endothermic peaks due to the melting of the compounds at 740 °C and 730 °C, respectively. Na₂U(MoO₄)₃ and Na₄U(MoO₄)₄, when heated in air atmosphere at 1200 °C, decomposed to form Na₂U₂O₇ which was confirmed by weight loss calculation and XRD.     

Sampling Boolean Functions over Abelian Groups and Applications

We obtain efficient sampling methods for recovering or compressing functions over finite Abelian groups with few Fourier coefficients, i.e., functions that are (approximable by) linear combinations of few, possibly unknown Fourier basis functions or characters. Furthermore, our emphasis is on efficiently and deterministically finding small, uniform sample sets, which can be used for sampling all functions in natural approximation classes of Boolean functions. Due to this requirement, even the simplest versions of this problem (say, when the set of approximating characters is known) require somewhat different techniques from the character theory of finite Abelian groups that are commonly used in other discrete Fourier transform applications. We briefly discuss applications of our efficient, uniform sampling methods in computational learning theory, efficient generation of pseudorandom strings, and testing linearity; we also state highly related open problems that are not only applicable in these contexts, but are also of independent mathematical interest. Received: December 14, 1998; revised version: October 20, 1999     

The R369 Myosin Residue within Loop 4 Is Critical for Actin Binding and Muscle Function in Drosophila

The myosin molecular motor interacts with actin filaments in an ATP-dependent manner to yield muscle contraction. Myosin heavy chain residue R369 is located within loop 4 at the actin-tropomyosin interface of myosin’s upper 50 kDa subdomain. To probe the importance of R369, we introduced a histidine mutation of that residue into Drosophila myosin and implemented an integrative approach to determine effects at the biochemical, cellular, and whole organism levels. Substituting the similarly charged but bulkier histidine residue reduces maximal actin binding in vitro without affecting myosin ATPase activity. R369H mutants exhibit impaired flight ability that is dominant in heterozygotes and progressive with age in homozygotes. Indirect flight muscle ultrastructure is normal in mutant homozygotes, suggesting that assembly defects or structural deterioration of myofibrils are not causative of reduced flight. Jump ability is also reduced in homozygotes. In contrast to these skeletal muscle defects, R369H mutants show normal heart ultrastructure and function, suggesting that this residue is differentially sensitive to perturbation in different myosin isoforms or muscle types. Overall, our findings indicate that R369 is an actin binding residue that is critical for myosin function in skeletal muscles, and suggest that more severe perturbations at this residue may cause human myopathies through a similar mechanism.