cssi/SciSciGPT-SciSciNet huggingface dataset:
Whole genome duplications, multi-break rearrangements, and genome halving problem

The Genome Halving Problem, motivated by the whole genome duplication events in molecular evolution, was solved by El-Mabrouk and Sankoff. The El-Mabrouk-Sankoff algorithm is rather complex inspiring a quest for a simpler solution. An alternative approach to Genome Halving Problem based on the notion of the contracted breakpoint graph was recently proposed in [2]. This new technique reveals that while the El-Mabrouk-Sankoff result is correct in most cases, it does not hold in the case of unichromosomal genomes. This raises a problem of correcting El-Mabrouk-Sankoff analysis and devising an algorithm that deals adequately with all genomes. In this paper we efficiently classify all genomes into two classes and show that while the El-Mabrouk-Sankoff theorem holds for the first class, it is incorrect for the second class. The crux of our analysis is a new combinatorial invariant defined on duplicated permutations. Using this invariant we were able to come up with a full proof of the Genome Halving theorem and a polynomial algorithm for Genome Halving Problem (for unichromosomal genomes). We also give the first short proof of the original El-Mabrouk-Sankoff result for multichromosomal genomes. Finally, we discuss a generalization of Genome Halving Problem for a more general set of rearrangement operations (including transpositions) and propose an efficient algorithm for solving this problem.
The ATXN2-SH2B3 locus is associated with peripheral arterial disease: an electronic medical record-based genome-wide association study.

Objectives: In contrast to coronary heart disease, genetic variants that influence susceptibility to peripheral arterial disease (PAD) remain unknown. Background: We performed a two-stage genomic association study leveraging an electronic medical record linked-biorepository to identify genetic variants that mediate susceptibility to PAD. Methods: PAD was defined as a resting/post-exercise ankle-brachial index (ABI) ≤0.9 or ≥1.4 and/or history of lower extremity revascularization. Controls were patients without history of PAD. In Stage I we performed a genome-wide association analysis adjusting for age and sex, of 561,490 SNPs in 1641 PAD cases (66±11 y, 64% men) and 1604 control subjects (61±7 y, 60% men) of European ancestry. In Stage II we genotyped the top 48 SNPs that were associated with PAD in Stage I, in a replication cohort of 740 PAD cases (70±11 y, 63% men) and 1051 controls (70±12 y, 61% men). Results: The SNP rs653178 in the ATXN2-SH2B3 locus was significantly associated with PAD in the discovery cohort (OR: 1.23; P=5.59x10-5), in the replication cohort (OR=1.22; 8.9x10-4) and in the combined cohort (OR=1.22; P-value: P=6.46x10-7). In the combined cohort this SNP remained associated with PAD after additional adjustment for cardiovascular risk factors including smoking (OR: 1.22; P=2.15x10-6) and after excluding patients with ABI >1.4 (OR: 1.237; P=3.98x10-7). The SNP is in near-complete linkage disequilibrium (r2=0.99) with a missense SNP (rs3184504) in SH2B3, a gene encoding an adapter protein that plays a key role in immune and inflammatory response pathways and vascular homeostasis. The SNP has pleiotropic effects and has been previously associated with multiple phenotypes including myocardial infarction. Conclusions: Our findings suggest that the ATXN2-SH2B3 locus influences susceptibility to PAD.
Learning from the Trends in Christian Higher Education

This special issue of Christian Higher Education encourages social scientists to learn from certain key contemporary and historical trends in order to increase the efficacy of Christian higher educ...
Purification and Characterization of an NADPH-Cytochrome P450 (Cytochrome c) Reductase from Spearmint (Mentha spicata) Glandular Trichomes

Solubilized NADPH-cytochrome c (P450) reductase was purified to homogeneity from an extract of spearmint (Mentha spicata) glandular trichomes by dye-ligand interaction chromatography on Matrex-Gel Red A and affinity chromatography on 2', 5'-adenosine diphosphate agarose. SDS-PAGE of the purified enzyme preparation revealed the presence of two similar proteins with masses of 82 kDa (major) and 77 kDa (minor) that crossreacted on immunoblot analysis with polyclonal antibodies directed against NADPH-cytochrome P450 reductase from Jerusalem artichoke and from mung bean. Complete immunoinhibition of reductase activity was observed with both types of polyclonal antibodies, while only partial inhibition of activity resulted using a family of monoclonal antibodies directed against the Jerusalem artichoke cytochrome P450 reductase. Inhibition of the spearmint oil gland cytochrome c reductase was also observed with the diphenyliodonium ion. The K(m) values for the cosubstrates NADPH and cytochrome c were 6.2 and 3.7 microM, respectively, and the pH optimum for activity was at 8.5. The NADPH-cytochrome c reductase reconstituted NADPH-dependent (-)-4S-limonene-6-hydroxylase activity in the presence of cytochrome P450, purified from the microsomal fraction of spearmint oil gland cells and dilauroyl phosphatidyl choline. These characteristics establish the identity of the purified enzyme as a NADPH-cytochrome P450 reductase.
Diffusion of a pulse in densely distributed scatterers

This paper presents a theoretical study on propagation and scattering characteristics of a short optical pulse in a dense distribution of scatterers. Examples include pulse diffusion in whole blood and in a dense distribution of particulate matter in the atmosphere and the ocean. The parabolic equation technique is applicable to the forward-scatter region where the angular spread is confined within narrow forward angles. When the angular spread becomes comparable to the order of unit steradian, there is as much backscattering as forward scattering and diffusion phenomena take place. We start with the integral and differential equations for the two-frequency mutual coherence function under the first-order smoothing approximation, and a general diffusion equation and boundary conditions are obtained. As examples, we present solutions for diffusion of a pulse from a point source and a plane wave incident on a slab of scatterers.
Statistical entropy of two-dimensional dilaton de Sitter space

Abstract It has been proposed that a quantum group structure underlies de Sitter/conformal field theory duality. These ideas are used to give a microscopic operator counting interpretation for the entropy of two-dimensional dilaton de Sitter space. This agrees with the Bekenstein–Hawking entropy up to a factor of order unity.
Layer by layer assembly of hybrid nanoparticle coatings for proton exchange membrane fuel cell bipolar plates

Abstract Optimum proton exchange membrane (PEM) fuel cell operation at low reactant gas stoichiometry requires that bipolar plate surfaces combine negligible electrical contact resistance with a high degree of hydrophilicity. Unfortunately, no single material can simultaneously satisfy both requirements. In the present work, we demonstrate that electrostatic layer by layer (LBL) assembly may be employed to design hybrid coating architectures composed of 5–10 nm thick graphite platelets and 19 nm diameter silica nanospheres. The strong cationic polyelectrolyte, acrylamide/β-methacryl-oxyethyl-trimethyl-ammonium copolymer, is used to deposit the two anionic nanoparticles from both discrete and mixed aqueous suspensions onto gold substrates. Low contact resistance is achieved by maintaining connectivity of the graphite nanoparticles throughout the coating thickness while good hydrophilicity is achieved by controlling graphite surface domain size. For ∼100 nm thick coatings, contact resistances as low as ∼4 mΩ cm2 may be obtained (comparable to that of a pure graphite platelet coating) while maintaining an advancing contact angle of ∼20° (comparable to that of a pure silica nanoparticle coating). This result represents an order of magnitude reduction in ohmic power loss for state-of-the-art PEM fuel cells relative to the use of pure silica nanoparticle coatings. While LBL assembly is a well-established technique for producing thin, layered structures of nanoparticles and polyelectrolytes, this work provides a unique architectural methodology by which domain distribution in heterogeneous nanoparticle coatings may be controlled.
Neural network filter for target detection in high-clutter imagery

The detection of objects in high-resolution aerial imagery has proven to be a difficult task. In our application, the amount of image clutter is extremely high. Under these conditions, detection based on low-level image cues tends to perform poorly. Neural network techniques have been proposed in object detection applications due to proven robust performance characteristics. A neural network filter was designed and trained to detect targets in thermal infrared images. The feature extraction stage was eliminated and raw gray-levels were utilized as input to the network. Two fundamentally different approaches were used to design the training sets. In the first approach, actual image data was utilized for training. In the second case, a model-based approach was adopted to design the training set vectors. The training set consisted of object and background data. The backpropagation training algorithm was modified to improve network convergence and speed and used to train the network. The neural network filter was tested extensively on real image data. Detection rates were determined for varying false alarm rates in each case. The detection and false alarm rates were excellent for the neural network filters. Their overall performance was much superior to that of the size- matched contrast-box filter, especially in the images with higher amounts of visual clutter.
The role of location and motion information in the tracking and recovery of moving objects

Observers in a multiple object tracking task can track about four to five independently moving targets among several moving distractors, even if all of the stimuli disappear for a 300-msec gap. How observers reacquire targets following such a gap reveals what kind of information they can maintain for targets. Previous research has suggested that participants maintain minimal information about a set of moving objects--namely, just their present spatial locations. We report five new experiments that demonstrate retention of location information for at least four objects, and extrapolated motion information for around two objects.
Square Pegs and Round Holes: Ruminations on the Relationship Between Performance Appraisal and Performance Management

Models of comprehensive Performance Management systems include both employee development and evaluative components. The Organizational Behavior Management discipline focuses almost exclusively on the developmental component, while the Industrial and Organizational Psychology discipline is focused on use of performance appraisals. Performance appraisals have several well-documented shortcomings. Despite those limitations, an examination of Performance Management models suggests that they often include an appraisal component. However, there is little consensus on how Performance Management should incorporate appraisals. The authors argue that performance data should be an output of a Performance Management process, not as an input or starting-point for developmental activities. This emphasizes goal-setting, feedback, and coaching throughout the year, and performance data are aggregated to provide enough information about performance to facilitate administrative decision-making when needed. An optimal perfor...
Principles and Limitations of the Rainville Methodology

The scope of audiometric assessment was greatly enhanced when M. Rainville introduced the concept of bone-conducted masking as an additional tool for the measurement of sensori-neural hearing level. Rain-ville's method is based on the principle that bone-conducted noise masks air-conducted tones in inverse proportion to degree of sensori-neural hearing loss. The principle advantages of the Rainville methodology are (1) ease of calibration, and (2) the virtual elimination of the problem of cross hearing which so frequently plagues the measurement of bone-conduction thresholds. The principle limitation of the Rainville methodology is that sensori-neural level is always measured in the occluded state. As a result of this fact, comparison of test results with bone-conduction levels obtained in the unoccluded state on patients with conductive loss can only be made by correcting for the average occlusion effect of the earphone used to deliver air-conducted tones to the test ear. This problem can be overcome by ...
Selected Temporal, Grammatical, and Phonological Characteristics of Conversational Utterances Produced by Children Who Stutter

The purpose of this study was to assess clause, syllable, and response latency characteristics of conversational utterances produced by children who stutter. Subjects were 14 boys who stutter (M ag...
Indocyanine green angiography and occult choroidal neovascularization.

Purpose: To evaluate the use of digital indocyanine green (ICG) angiography as an adjunct to fluorescein angiography in the diagnosis and treatment of ill-defined choroidal neovascularization (CNV) associated with age-related macular degeneration (AMD). Methods: The authors retrospectively reviewed all ICG angiograms performed at Wills Eye Hospital from March to July 1992. Included in this study were all cases with exudative manifestations of AMD in which fluorescein angiography showed ill-defined CNV. The initial ICG findings and the clinical outcome of both treated and untreated cases were evaluated through 6 months of follow-up. Results: Of the 101 eligible cases, ICG angiography at presentation demonstrated well-defined hyperfluorescence in 40 cases (group 1), ill-defined hyperfluorescence in 43 cases (group 2), mixed pattern of well- and ill-defined hyperfluorescence in 14 cases (group 3), and no abnormalities in 4 cases (group 4). Approximately one half of the cases with well-defined ICG hyperfluorescence (21 % of the total) had only extrafoveal changes. Laser photocoagulation treatment based solely on ICG angiogram findings was performed in 19 group 1 cases (extrafoveal hyperfluorescent foci only) and in 8 group 3 cases, with treatment in both groups being directed only to areas of welldefined hyperfluorescence. Successful treatment was achieved in 12 (63%) of 19 cases and in 2 (25%) of 8 cases, respectively. There was a strong correlation between posttreatment persistence or recurrence of ICG hyperfluorescence and treatment failure. Conclusions: Indocyanine green angiography is a valuable diagnostic adjunct to fluorescein angiography in evaluating occult CNV in AMD. In this series, well-defined, extrafoveal ICG hyperfluorescence was identified in 21% of the cases, and preliminary, short-term results suggest that ICG-guided laser treatment is promising in this subgroup.
Progress in the isolation and characterization of a host hemolymph ovipositional kairomone for the endoparasitoid Microplitis croceipes.

The purpose of this study was to (1) define further the bioassay parameters of an ovipositional stimulating kairomone (OSK) for Microplitis croceipes found in the hemolymph of the corn earworm, Heliothis zea; (2) purify and isolate the OSK; and (3) determine the viability of the eggs oviposited into an artificial ovipositional substrate (AOS). Phenylthiourea (PTU), added to hemolymph to prevent melanization, and host feces which contains a host-seeking stimulant (Jones et al.: Sciences 173:842, 1971) [1], were eliminated as possible factors influencing egg laying in the bioassay. Extraction of hemolymph with ether, hexane, and to a lesser degree with methylene chloride removed lipids without loss of OSK activity. In contrast, extraction with polar solvents such as methanol tetrahydrofuran, and acetonitrile resulted in a loss of OSK activity. After ether extraction, the sample could be concentrated by rotoevaporation (90°C) or lyophilization without loss of OSK activity. Fractionation of the sample by gel permeation chromatography indicated a molecular weight of between 100–300 daltons. The OSK was extracted to a specific activity higher than crude hemolymph on two disposable solid-phase adsorbants, a normal-phase diol, and a reverse-phase phenyl material. Subsequent fractionation of hemolymph on a phenyl adsorbent column by HPLC indicated that the OSK contained at least two components. Ovipositional activity was obtained only when two fractions with different retention volumes were combined. Preparation of the AOS's from agar plus Goodwin's tissue culture medium maintained viability of the oviposited eggs. Thirty-seven percent of the eggs that were removed from the AOS's and held in culture media eventually hatched.
Emission lines from condensing intracluster gas

We present computations of the emission-line spectra produced when hot gas cools nonuniformly. During inhomogeneous cooling, soft X-ray/extreme ultraviolet radiation from 10(exp 5) to 10(exp 7) K gas photoionizes coexisting clouds that have already cooled to 10(exp 4) K. Thus, strong emission lines emerge from both the high-ionization cooling gas and embedded low-ionization knots. This mechanism, which ought to operate naturally within the sonic radii of cooling flows, can generate optical emission-line spectra similar to those observed at the centers of many clusters of galaxies thought to contain such flows. We have computed the X-ray, ultraviolet (UV), optical, and infrared (IR) emission-line fluxes expected under a variety of intracluster conditions so that the self-irradiation hypothesis can be compared thoroughly with observations. If this picture is found to be adequate, the models can also be used to measure mass flow rates and inflow velocities in the vicinities of cooling-flow nebulae and to constrain the column densities and covering factors of condensed material at the centers of these clusters.
Representative Democracy as a Necessary Condition for the Survival of a Federal Constitution

It does not follow from the supposition that the union is beneficial that its terms would go unchallenged by its members. The argument in this article suggests that federal stability (robustness) requires for itself a well-functioning democratic process, which satisfies a fairly restrictive condition. A necessary condition for the resiliency of the federal regime is a representative democracy; furthermore, it is the representative democracy in which rewards to the representatives are only in part vested in their parochial constituencies, while in the other part come form other sources, e.g., from an oversized at-large coalition. The requirement to the democratic process is, of course, only a necessary, not a sufficient condition for the federal success. Yet, we argue in this essay that only the states with well-developed (properly institutionalized) democratic electoral competition have a chance to form a resilient federal union and sustain their federal constitutional arrangements not just in form, but in their political practice as well. Copyright 2007, Oxford University Press.
Computer personnel selection and criteria development

This is a report on the job analysis phase of a research program devoted to computer personnel selection and evaluation. The research program is being carried out by the Electronics Personnel Research Group attached to the Department of Psychology at the University of Southern California. The Electronic Personnel Research Group activities are sponsored by the Office of Naval Research, the Bureau of Personnel, and the Bureau of Ships. The principal investigator of the various research projects and leader of the group is Dr. Joseph W. Rigney. The Electronics Personnel Research Group, or EPRG, has been conducting studies at USC since 1952, principally in the matters of electronics equipment, maintenance and operation. The research has been on personnel factors in the areas of selection, performance evaluation, and training. In 1959, EPRG surveyed the computer field and put out four technical reports which dealt with problems associated with the establishing of computer installations and of the personnel requirements. These were titled, "The Role of Humans in Complex Computer Systems". (Technical reports No. 24, 25, 26, and 27.) The objective was to provide information to the Navy on computer installation requirements. The reports were of such general interest that many other agencies have found them valuable. For example, the city of San Francisco Controller Office, which is in the process of computerizing many of the city's civil functions, has acknowledged their use of the reports.
Genetic influences on rheumatoid arthritis in African Americans.

Rheumatoid arthritis is a common autoimmune disease characterized by inflammation of the synovial membrane of diarthrodial joints, which often leads to joint damage and disability. There are known associations between major histocompatibility complex class II alleles and susceptibility to rheumatoid arthritis and its severity in Caucasians. African Americans, an admixed population in the United States, has been underrepresented in genetic studies of the susceptibility and severity of rheumatoid arthritis. With the advent of biologic agents, which target specific molecules of the immune system (e.g., tumor necrosis factor, interleukin-1), biologic markers of treatment response in Caucasians and in African Americans would be clinically useful.
Interpersonal Distress is Associated with Sleep and Arousal in Insomnia and Good Sleepers

Objective The interpersonal environment is strongly linked to sleep. However, little is known about interpersonal distress and its association with sleep. We examined the associations among interpersonal distress, objective and subjective sleep in people with and without insomnia.
Halo and devil effects demonstrate valenced-based influences on source-monitoring decisions.

Abstract Source attributions based on positive versus negative valence were examined in four experiments. The two sources were individuals who were depicted positively or negatively, and the content of their statements was similarly valenced. When valenced information about the sources was provided after learning the statements, test biases to attribute positive statements to the positive source and negative statements to the negative source were strongly present. Providing the same information prior to learning improved memory, but did not entirely eliminate test biases based on valence. Signal detection analysis suggests that these “halo effect” biases are criterion-based and not memory-based. Therefore, the results are more consistent with descriptions of source-monitoring processes that can benefit from familiarity-based partial information as opposed to descriptions in which source monitoring is primarily recollection-based.
Genetic and maternal effects on seedling characters of Solidago altissima (Compositae)

The relative contributions of genetic and maternal factors to phenotypic variation were studied in seedlings of the clonal herb Solidago altissima L. Pairwise crosses were made to establish 19 full-sibships. Because crosses were reciprocal, each parent served as seed parent to half its offspring and as pollen parent to the other half. For 18 characters, genetic variation was estimated from the between sibship variance and maternal variation from the variance between maternal groups within sibships. Early in the growing season, maternal effects exerted strong influence over variation in leaf and stem dimensions, while genetic influences were weak or absent. At the end of the season genetic influences on leaf and stem dimensions, relative biomass allocation between stem and leaves, and the propensity to flower were significant but maternal effects were not. However, both genetic and maternal influences were found on the number and lengths of new rhizomes. Phenotypic, genetic, and maternal correlation matrices were examined through principal component analysis for trade-offs among vegetative growth, clonal expansion and floral reproduction which could constrain the evolution of life history patterns. At the phenotypic level, seedlings with strong vegetative growth produced more and longer rhizomes, and were more likely to flower. Genetically, correlations among these functions were weak or absent. Strong maternal contributions to seedling vegetative growth correlated positively with the number and length of rhizomes. Thus, no trade-offs acting during the seedling stage were found. However, there were indications of a genetically influenced trade-off between the number of rhizomes produced in the seedling year with the size of the ramets produced in the second year.
Control over spectral content via differential pumping of a monolithic passively mode-locked quantum dot laser

A monolithic two-section quantum dot semiconductor laser is differentially pumped to form non-uniform current injection in the gain region. We show that the nature of the spectral content in the output signal is affected by this differential pumping; despite the fact that the separately pumped gain regions are not electrically isolated in this device. Both negative (red-shift) and positive (blue-shift) spectral chirps were observed during mode-locked operation. It is also demonstrated that mode locked operation is achieved with a much larger set of injection current / absorber bias voltage pairs than was previously possible with single-pad current injection.
Can less environmental disclosure have a legitimising effect? Evidence from Africa

Abstract Organizational legitimacy theory predicts that corporations will do whatever they regard as necessary in order to preserve their image of a legitimate business with legitimate aims and methods of achieving it. Legitimacy is mostly used in the social and environmental accounting research (SEAR) literature to support the idea that social disclosures will be maintained at present levels, or increased over time, to avert legitimacy crises. However, the SEAR literature contains some references to reasons for, and incidents of, reductions in social disclosures. We submit that legitimacy theory predicts these reductions as much as it predicts maintaining or increasing disclosure levels. We conduct a content analysis of more than 140 corporate annual reports over a 9-year period in order to identify the trends in environmental disclosure by South African companies over time. We find a reduction in environmental reporting after an initial period of increases for both Mining companies and Top-100 industrial companies. The decrease for Mining companies was bigger than that for Top-100 companies, both overall and when the results were split between specific and general information. The publication of general and specific information increased from 1994 to 1999; disclosure of specific information then declined by five times more than the decline in disclosure of general information. These trends are consistent with legitimacy theory and we conclude that legitimising objectives may also be served by changing the type (general/specific) or reducing the volume of environmental disclosures.
Extensions of Szego's theory of rational functions orthogonal on the unit circle

Rational functions orthogonal on the unit circle with prescribed poles lying outside the unit circle are studied. We study the asymptotic behaviors for the orthogonal rational functions when the measure does not satisfy the Szego condition.
Structural and functional effects of high prolactin levels on injured endothelial cells: evidence for an endothelial prolactin receptor.

Stress has been linked to health problems such as atherosclerosis and prolonged wound healing, which involve the responses of injured endothelial cells. Though prolactin (PRL) levels become increased during the physiological response to stress, the significance and effects of these increases are largely unknown. Here we examined the effects of elevated, though physiological, concentrations of PRL on the responses of cultured endothelial cells after mechanical injury to cell monolayers. When treated at the time of injury with PRL levels of 62.5–1000 ng/mL, cells at the wound front became abnormal in shape and had reductions in f-actin staining in comparison to controls that were not PRL-treated. High PRL concentrations also inhibited the adhesion of cells to their growth surface in a dose-dependent manner. Using rhodamine-labeled PRL, we observed specific PRL uptake by these cells that suggested the presence of a PRL receptor. Finally, mRNA for the long form of the PRL receptor was detected by RT-PCR. To our knowledge, this is the first report demonstrating that (1) high PRL concentrations alter the actin cytoskeleton and adhesion of injured endothelial cells and (2) endothelial cells express the transcript for the PRL receptor. Thus, we report novel effects of PRL that may be mediated by activation of an endothelial cell PRL receptor.
Ultrastructural changes in female hepatocytes during ovarian maturation of Steindachnerina insculpta (Pisces: Curimatidae).

During gonadal maturation the females of Steindachnerina insculpta, a teleost of the Furnas reservoir, Minas Gerais, Brazil, show low hepatosomatic and high gonadossomatic indexes, suggesting possible transference of hepatic substances to the ovaries. In comparison to the resting phase, in the maturation/mature one the hepatocytes show greater development of both smooth and rough endoplasmic reticula, increased electron density in the mitochondria, and glycogen scattered throughout the cytoplasm. In both resting and maturation/mature phases, the hepatic parenchyma contains melanomacrophagic centers that consist of degenerating cellular debris and are surrounded by capsules formed by cells, resembling fibroblasts, joined by desmosomes. No physiological relation of these centers with ovarian maturation was found.
The Thermochemical Kinetics of Retro “-Ene” Reactions of Molecules with the General Structure (Allyl)XYH in the Gas Phase. 8.. The Thermal Decomposition of Methylallylaniline in the Gas Phase†

The thermal decomposition of N-methyl-N-allylaniline in the gas phase over the temperature range 575 to 665 K appears to be a homogeneous radical chain reaction yielding allyl and C6H5NCH3 radicals in the primary step as is indicated by the numerous chain-terminating radical recombination products and the effect of diluents on the rate constants. From experiments carried out with excess of diluent, first order rate constants which can be identified with the rate determining chain initiating step, were calculated using the internal standard technique and found to fit the Arrhenius relationship . Although the Arrhenius parameters are slightly low, which is attributed to some loss of substrate by secondary reactions, they are in general agreement with prediction. The relevance of these results to the thermal behavior of allylamines and the nature of six-center transition states is discussed.
An elastic-plastic indentation model and its solutions

An analytical model of hardness has been developed. Four major indentation tests, namely indentation by cones, wedges, spheres, and flat-ended, axisymmetric cylinders have been analyzed based on the model. Analytical relationships among hardness, yield stress, elastic modulus, Poisson's ratio, and indenter geometries have been found. These results enable hardness to be calculated in terms of uniaxial material properties and indenter geometries for a wide variety of elastic and plastic materials. These relationships can also be used for evaluating other mechanical properties through hardness measurements and for converting hardness from one type of hardness test into those of a different test. Comparison with experimental data and numerical calculations is excellent.
1,2-diaminobenzene adducts of nickel(II) 1,3-diketonates: Their role in dibenzotetraaza[14]annulence macrocycle formation

Abstract The attempted preparation of the macrocyclic ligand,6,8,15,17-tetraphenyldibenzo[b,i][1,4,8,11]tetraazacyclotetradecine from 1,2-diaminobenzene, 1,3-diphenyl-1,3-propanedione, and nickel(II)acetate via a template condensation is unsuccessful because of severe steric interactions in the desired product. The product isolated from this reaction, in high yield, is the bis(1,2-diaminobenzene) adduct of bis(1,3-diphenyl-1,3-propanedionato) nickel(II). Crystals of the adduct are monoclinic with a = 7.425(1), b = 12.221(3), c = 19.194(3) A, β = 97.01°, Z = 2, V = 1728.7 A 3 , and space group P 2 1 / n . The structure was solved by the heavy atom method and difference Fourier techniques, and refined by the block-diagonal least-squares method to a final R of 0.0379 for 2218 reflections with I >2σ( I ). An empirical absorption correction was made via ψ-scan of 5 reflections with 2θ-values between 5 and 90°, and χ close to 90°. The compound consists of a square planar Ni(II)O 4 array with two molecules of axially coordinated diamine. The monodentate trans arrangement of a diamine molecules gives the compound the overall pseudo-octahedral geometry that is common to adducts of metal 1,3-diketonates. The 6,8,15,17-tetramethyl macrocycle is readily formed via template condensation when the diketone employed is 2,4-pentanedione. The bis(1,2-diaminobenzene) adduct of bis(2,4-pentanedionato)nickel(II) has also been prepared. A small amount of macrocycle can be detected by refluxing this latter adduct in alcohol. The principal product is (1,2-diaminobenzene) tetrakis(2,4-pentanedionato)dinickel(II).
Advanced biorefinery in lower termite-effect of combined pretreatment during the chewing process.

Background Currently the major barrier in biomass utilization is the lack of an effective pretreatment of plant cell wall so that the carbohydrates can subsequently be hydrolyzed into sugars for fermentation into fuel or chemical molecules. Termites are highly effective in degrading lignocellulosics and thus can be used as model biological systems for studying plant cell wall degradation.
Characteristics of spin-on ferroelectric SrBi2Ta2O9 thin film capacitors for ferroelectric random access memory applications

We report on the properties and characterization of SrBi 2 Ta 2 O 9 (SBT, or Y − 1) thin film capacitors for ferroelectric random access memory (FERAM) applications. The films were prepared by spin-coating from carboxylate precursors. The remanent polarization ( P r ) was 5−6 μ C/cm 2 and the coercive field was ∼55 kV/cm. Excellent fatigue endurance was observed up to 10 11 cycles. Auger analysis indicates bismuth diffusion through the Pt electrode after capacitor anneal which might require excess Bi in the precursor solution for stoichiometry control. No detectable amount of α emission was found from SBT films, which reduces the possibility of soft error when used in the memory devices.
The Transition to Modern Agriculture: Contract Farming in Developing Economies

Recent years have seen considerable interest in the impact of contract farming on farmers in developing countries, motivated out of belief that contract farming spurs transition to modern agriculture. In this article, we provide a thorough review of the empirical literature on contract farming in bo
The Digestive System of Diaphorina citri and Bactericera cockerelli (Hemiptera: Psyllidae)

ABSTRACT The psyllids Diaphorina citri (Kuwayama) and Bactericera cockerelli (Sulc) (Hemiptera: Psyllidae) are vectors of Candidatus Liberibacter spp., bacterial agents of serious agricultural diseases. The rapidly expanding geographical distributions of these diseases dictate increasing urgency for their control. Therefore, it is important to gain a full understanding of the psyllid digestive system in which the vector—pathogen interactions begin. Their midgut is looped so that the foregut—midgut and midgut—hindgut transitional regions are grafted together to form a composite tube within a filter chamber sheath. Unwanted sap components could thus be extracted directly into the hindgut, bypassing digestion. The esophageal lumen enters the chamber axially to become the inner midgut lumen. The upper half of this midgut section is bulbous while the lower half is tubular. The tube lumen exits the chamber to become the external midgut lumen, which loops through the hemocoel and reenters the chamber, becoming t...
Immediate Influence of the Thoracic Flexion Exercise on Vertebral Position in Milwaukee Brace Wearers

Fourteen female subjects with idiopathic scoliosis and in Milwaukee brace programs participated in a study to determine if the performance of a thoracic flexion exercise recommended by Blount and Moe was effective in immediately reducing thoracic vertebral rotation and lateral deviation. The study found the exercises effective in reducing vertebral rotation and lateral deviation for the duration of the exercise.
Social Skills Interventions for Young Children with Disabilities A Synthesis of Group Design Studies

This study synthesizes the findings of social skills interventions conducted with 3- to 5-year-old children with disabilities between 1975 and June of 1999. An extensive search of the professional literature yielded a total of 23 group-design intervention studies that met criteria for inclusion in the synthesis. The synthesis provides a description of the purpose, procedures, measures, and findings of each study as well as an analysis of effect size outcomes in relation to critical features of the primary studies. Positive outcomes were associated with a range of interventions, including modeling, play-related activities, rehearsal/practice, and/or prompting.
Preoperative Needle Biopsy as a Potential Quality Measure in Breast Cancer Surgery

Preoperative needle diagnosis (PND) is being considered as a quality measure in breast cancer surgery. This criterion has not been thoroughly evaluated in the literature. The purpose of this study is to assess ease of access to these data and rate of compliance in a tertiary care center. We retrospectively reviewed all our breast cancer cases between July 2006 and July 2007. The data were queried for preoperative needle diagnosis. Charts of patients who did not meet this criterion were reviewed to determine the cause for noncompliance. In the year 2006–2007, 396 breast cancer operations were performed (age range 19–96 years). Of 396 cases, 43 (11%) underwent a surgical procedure without diagnosis of cancer. In 19/396 (5%) cases PND was not feasible due to technical reasons. In 22/396 (5.5%) cases, preoperative needle biopsy did not render a malignant diagnosis: the pathology report was discordant with the radiological or clinical findings, or the needle biopsy result necessitated surgical resection. In only 2 of 396 cases (0.5%) was PND not attempted: an 80-year-old woman with a radiologically and clinically malignant mass, and a 43-year-old woman with a clinical and ultrasonographic suggestion of fibroadenoma. We conclude that data for preoperative needle diagnosis were easily accessible in our center. If this criterion is used as a quality measure in breast cancer surgery, 100% compliance may not be an achievable goal.
Prognosis of Patients Taking Selective Serotonin Reuptake Inhibitors Before Coronary Artery Bypass Grafting

Depression is increasingly recognized as an independent prognostic risk factor in patients with coronary artery disease and coronary artery bypass grafting (CABG). The use of selective serotonin reuptake inhibitors (SSRIs) for depression in patients with cardiac disease is becoming more prevalent. We examined the long-term outcomes of patients on SSRIs before CABG. We prospectively examined collected data in the Duke Databank for Cardiovascular Disease from January 1, 1999 to December 31, 2003. The median and maximum follow-up periods were 3 and 6 years, respectively. We screened patients who underwent CABG (n = 5,364) and excluded those who underwent simultaneous CABG and valvular surgery (n = 570). SSRI antidepressants included fluoxetine, fluvoxamine, paroxetine, sertraline, citalopram, escitalopram, venlafaxine, and clomipramine, and their use was determined from the inpatient pharmacy records during the index hospitalization. Outcomes included event-free survival from all-cause mortality, rehospitalization, and a composite end point of all-cause mortality or rehospitalization. Of 4,794 CABG-only patients, 246 (5.1%) took SSRIs before CABG. The SSRI group had a higher prevalence of diabetes, hypercholesterolemia, hypertension, cerebrovascular disease, peripheral vascular disease, and previous cardiovascular intervention. After adjustment for baseline differences, patients on SSRIs before CABG had increased risks of mortality, rehospitalization, and the composite end point (hazard ratio 1.61, 95% confidence interval 1.17 to 2.21, p = 0.003; hazard ratio 1.52, 95% confidence interval 1.30 to 1.77, p <0.0001; and hazard ratio 1.46, 95% confidence interval 1.26 to 1.70, p <0.0001, respectively). In conclusion, SSRI use before CABG was associated with a higher risk of long-term post-CABG mortality and rehospitalization. The explanation behind these findings requires further research.
Collaborating Across the Miles: Telecollaboration in a Social Studies Methods Course

This study considers the enrichment of social studies methods through the integration of videoconferencing in a telecollaborative format. The purpose in developing this study was threefold: (a) to describe the perspectives of teacher candidates while participating in a telecollaborative social studies methods course experience, (b) to determine in what manner videoconferencing could enhance a methods course, and (c) to determine if telecollaboration could be successfully and seamlessly integrated within the course. Following a review of the literature, the program is described and teacher candidate perceptions are shared. Findings reveal limitations and challenges for social studies methods instructors. Suggestions for future telecollaborative experiences are provided. It is common for social studies teachers to encourage cooperation, respect, and clear communicatio n in the classroom. It is not so common for true, substantive collaboration to be a part of classrooms every day, mainly due to inexperience, inconvenience, lack of shared planning time, and minimal administrative/technical support. Consider the following scenarios related to teacher education candidates’ experiences planning for instruction with and without a collaborative context:
The cross as Christ's weapon: the influence of heroic literary tradition on The Dream of the Rood

In spite of all that is known of the religious, cultural and literary background of The Dream of the Rood in general, the genesis of its form, and especially of its most immediately striking and unique feature, the device of the speaking cross, has so far resisted attempts at explanation and remains something of a mystery. Albert S. Cook long ago called attention to similarities between the mode of portrayal of the cross and the medieval traditions of epigram, epigraph and riddle, while not going so far as to suggest that these traditions had a direct influence on the poet. Now it is true, of course, that our earliest text of the poem is the series of inscriptions on the Ruthwell Cross, but these inscriptions are strikingly different from all others from the Anglo-Saxon period through which inanimate objects are personified and speak. The inscription on Alfred's Jewel, ‘AElfred mec heht gewyrcean’, for instance, and those, some of them in the first person, in Latin and English, on the blades, hilts and scabbards of various swords and knives are generally quite brief – limited to a simple statement of the object's name, its maker's name or that of its owner – are seldom metrical and, most important, are not couched in the kind of heroic diction used in the poem. While it is quite possible that the poet sensed an analogy between such inscriptions and his personification of the cross, what these inscriptions manifestly lack is the literary quality intrinsic to his personification – whether on the Ruthwell Cross or in the Vercelli Book. Only a literary explanation can account for this.
Technology Assessment and Idealized Design

This is an essay about the anticipatory assessment of telecommunications technologies for the production, dissemination and use of scientific and technological information (STI) in the United States. The focus is on the 1980’s. The question posed is: What should be done, not only by government and industry, but also by the myriad interest groups with a stake in the information system, to generate and implement better alternatives in the next ten years?
Comments concerning “The density, the refractive index and the adjustment of the excess thermodynamic properties by means of the multiple linear regression method for the ternary system ethylbenzene–octane–propylbenzene”

Abstract The comment points out several mathematical shortcomings in the published paper by Lisa and coworkers, including the use of an incorrect form for the Redlich–Kister equation for a ternary system.
A framework for learning and reuse in visual programming environments: supporting novice programmer development of educational simulations

Incorporating computers into daily K-12 classroom teaching promises to benefit student learning, and improve teaching practice substantially. Computer enhanced curricula may enable more teachers to create exploratory and inquiry based lessons, but in most cases supporting software have only been realized as practice tools for specific rote learning skills. Drills do little to help students develop higher-order reasoning and problem-solving skills. With more computers in the classroom, the assumption was that computers would be integrated into curricula with a high usage of educational software, but research suggests that this assumption has not been borne out (Powell & Okey, 1994; Tyack & Cuban, 1995). Our general argument is that systems whose usability characteristics have been designed to meet teachers’ needs and that can be easily tailored to meet specific teaching objectives are more likely to be incorporated into everyday teaching practices. One type of computer-based activity that enables teachers to engage students in exploratory learning is an educational simulation. Many educational software packages that build simulations have limited usability because they have unmodifiable, limited modifiable or difficult-to-modify functionality. Still others are useful, but are too expensive for many schools to afford. These packages fall short of achieving the ultimate goal of providing useful classroom simulation technology—providing teachers with the option of building simulations from scratch or reusing existing simulations by adapting their functionality. Because teachers have limited time to learn new technology or develop new simulations, this research focused on developing a new framework that would help teachers create easily adaptable and reusable customized educational materials, encouraging them to use these materials to build and extend simulations in collaboration with their students. We began our study by analyzing the currently available tools for visual construction of educational simulations; we used the results of these analyses to develop an alternative environment—SimBuilder. This environment was designed to address the general usability and programming style issues observed in our analysis of other tools. A minimalist self-study tutorial was designed to support rapid start-up and use of the SimBuilder. Through a comparative analysis using a state-of-the-art environment (AgentSheets) that collected a wide range of quantitative and qualitative measures of learning, programming style, usability, motivation, and strategies for code reuse, we determined that SimBuilder offers an improved environment for teachers to construct educational simulations.