cssi/SciSciGPT-SciSciNet huggingface dataset:
The shuffling of mathematics problems improves learning

In most mathematics textbooks, each set of practice problems is comprised almost entirely of problems corresponding to the immediately previous lesson. By contrast, in a small number of textbooks, the practice problems are systematically shuffled so that each practice set includes a variety of problems drawn from many previous lessons. The standard and shuffled formats differ in two critical ways, and each was the focus of an experiment reported here. In Experiment 1, college students learned to solve one kind of problem, and subsequent practice problems were either massed in a single session (as in the standard format) or spaced across multiple sessions (as in the shuffled format). When tested 1 week later, performance was much greater after spaced practice. In Experiment 2, students first learned to solve multiple types of problems, and practice problems were either blocked by type (as in the standard format) or randomly mixed (as in the shuffled format). When tested 1 week later, performance was vastly superior after mixed practice. Thus, the results of both experiments favored the shuffled format over the standard format.
Study of two‐dimensional transport processes in photoconductive materials by fluctuation theory

Several investigators have found experimentally that photoconductors, in contrast to semiconductors, exhibit diffusion as the dominant transport process even with high electric fields applied. This effect is analysed by solving the two-dimensional transport equation governing the photoconductive carrier density fluctuations for the noise spectra. The prevailing transport processes and corresponding noise spectra are then analysed in terms of the crystal geometry, applied electric field, temperature, diffusion constant, and surface recombination velocities. Verschiedene Autorenn haven experimentell ermittelt, das Photoleiter, im Gegensatz zu Halbleitern, Diffusion als hauptsachlichen Transportvorgang aufweisen, selbst bei groseren elektrischen Feldstarken. Dieser Effekt wird durch Losung der zweidimensionalen Transportgleichung analysiert, die die Dichteschwankungen der Photoleitungstrager und somit die Rauschspektren bestimmen. Die vorherrschenden Transportvorgange und ihre entsprechenden Rauschspektren werden dann im Bezug auf Kristallgeometrie, elektrische Feldstarke, Temperatur, Diffusionskonstante und Oberflachenrekombinationsgeschwindigkeit untersucht.
Early work experience: A partial antidote for adolescent egocentrism.

One of the most important lessons a young person may learn from working is how to interact effectively with others. This potential outcome of work experience has received virtually no attention from proponents of the early integration of adolescents into the workplace. In this paper we suggest that working may contribute to the development of more advanced social understanding (i.e., social sensitivity, social insight, and effective social communication and manipulation) by requiring youngsters to (a) shift back and forth between diverse roles and (b) interact frequently with strangers. Illustrative material is presented from interviews with 100 working adolescents and their parents.
Molecular systematics of the family Mormoopidae (Chiroptera) based on cytochrome b and recombination activating gene 2 sequences.

We examined 1140 bp of the mitochondrial cytochrome b gene and 1398 bp of the nuclear RAG2 gene to investigate the systematics of the eight species of bats within the family Mormoopidae. It was concluded that within the genus Pteronotus there were four valid subgenera: Phyllodia, Chilonycteris, Pteronotus, and an undescribed subgenus. Within Pteronotus, P. parnellii either was part of an unresolved tetratomy with the other three subgenera (cytochrome b data) or was basal (RAG2 and combined data). For three species, P. gymnonotus, P. macleayii, and P. quadridens, our sample revealed little geographic variation. In P. davyi and P. parnellii, the magnitude of genetic distance suggests the possibility of two biological species existing within the currently recognized taxa. Within P. personatus, there was substantial geographic variation partitioned in a step-like fashion among our specimens. Neither of the species within the genus Mormoops showed the deep distance nodes present in P. davyi, P. parnellii, and P. personatus. Cytochrome b and RAG2 data indicated that M. megalophylla evolved recently from its common ancestor. Although there was considerable agreement among the branching patterns for the nuclear and mitochondrial genes, both genes failed to provide robust data concerning the evolutionary relationships among the subgenera.
Properties of the DNA-delay mutants of bacteriophage T4.

Abstract The intracellular events following infection with T4 DNA delay mutants have been examined in detail. The mutants fall into four complementation groups, rather than five as had been thought. Both the eclipses and latent periods of the mutants are extended in comparison to wild type. DNA synthesis was followed after infection by diphenylamine assay and by uptake of radioactive thymidine. DNA replication by the mutants appears to initiate at the normal time but at a reduced rate. Density transfer experiments support this conclusion. After 10–15 min of replication, the rate of DNA synthesis increases markedly. Net synthesis of late protein also is affected in these mutants since, in contrast to wild type, the rate of uptake of radioactive leucine declines at 15–20 min after infection. Appearance of phage lysozyme is delayed several minutes; appearance of g23 protein is delayed 5–10 minutes and the final rate of synthesis is reduced as much as 2-fold. Net RNA synthesis as measured by uptake of radioactive uracil appears normal, but phenotypic reversion experiments using 5-fluorouracil suggest that the synthesis of late messenger may be delayed in some of the mutants.
Stable isotope analysis at the molecular level: A new approach for determining the origins of amino acids in the Murchison meteorite

A combined gas chromatography/isotope ratio mass spectrometry (GC/IRMS) method has been developed that permits the direct stable carbon isotope analysis of N(O)-trifluoroacetyl-isopropyl esters of individual amino acids and their respective enantiomers at nanomole abundances. Calculation of the original delta C-13 values of the amino acids is accomplished via a correction for the carbon introduced during the derivatization process. Previous GC/IRMS analyses of individual amino acids in the non-hydrolyzed water extract of an interior sample of a Murchison meteorite stone revealed an enrichment in C-13 relative to terrestrial organic matter, in agreement with previous findings for bulk extracts. The range of amino acid delta C-13 values (+5 to +30 per mill, PDB) suggests possible kinetic effects during synthesis. In this study, an apparent kinetic isotope effect was also observed for the amino acid products of a spark discharge experiment. These preliminary resutls are supportive of a similar mechanism for the abiotic synthesis of amino acids in the Murchison meteorite.
Synthesis of the analogue nucleoside 3-deaza-2′-deoxycytidine and its template activity with DNA polymerase

Abstract A new synthesis of the nucleoside analogue 3-deaza-2′-deoxycytidine is described. The N 3 -nitrogen of dC is involved in the central hydrogen bond of a dG-dC base pair. The relative importance of hydrogen bonding as a controlling factor in the activity of DNA polymerase is examined by studying both duplex stability and template effects for this dc 3 C nucleoside. Duplexes containing dG-dc 3 C base pairs were strongly destabilized while templates containing the analogue nucleoside were found to incorporate only the complementary dG triphosphate, similar to observations with templates containing the native 2′-deoxycytidine.
ECOLOGICAL DISTRIBUTION OF THE SALAMANDERS GYRINOPHILUS AND PSEUDOTRITON IN A SOUTHERN APPALACHIAN WATERSHED

The stream-type larval forms of the hemidactyliine plethodontid salamanders Gyrinophilus porphyriticus, Pseudotriton montanus, and P. ruber show subtle interspecific variation in pigmentation and body proportions. I tested the hypothesis that morphological divergence is correlated with adaptive diversification in habitat selection by evaluating the ecological distribution and habitat affinities of larvae of these species in the Chattooga River watershed of the southern Blue Ridge Physiographic Province. Pseudotriton montanus was observed in a single habitat, a bottomland swamp in the floodplain of a third-order stream. Both G. porphyriticus and P. ruber showed an affinity for springs, although the latter had a wider distribution in higher-order streams and small ponds. In springs, larvae of G. porphyriticus showed a greater preference for rheocrenes and a proclivity for burrowing in the coarse substrates of these habitats; in contrast, larvae of P. ruber were more common in limnocrenes and helocrenes, whi...
Error-Aware Algorithm/Architecture Coexploration for Video Over Wireless Applications

In this article, we propose a cross-layer algorithm/architecture coexploration for wireless multimedia systems to coordinate interactions among sublayer optimizers for improvements in energy/QoS/reliability. By exploiting the inherent redundancy in wireless multimedia systems, we generate an expanded design space over traditional layer-specific approaches. Specifically, we control the error resilient encoder at the application layer to provide awareness of architectural exploration at the physical layer allowing new design points with lower power consumption via aggressive voltage scaling. While trying to reduce energy consumption, the fault tolerant technique compensates the effect of the hardware and network errors due to aggressive voltage scaling and lossy transmission, respectively. Our experiments on H.263 video over a WCDMA communication system demonstrate that coexploration enlarges the feasible design space, which results in significant power savings of more than 20p in the WCDMA modem.
Structural, optical, and electrical studies of amorphous hydrogenated germanium

Abstract High-density, non-porous, highly photoconductive films of amorphous hydrogenated germanium (a-Ge:H) showing minimal microstructure were prepared using the r.f. glow discharge method out of a gas plasma of GeH4 and H2. These films, deposited onto substrates mounted on the powered electrode of a diode reactor, showed remarkable improvement over codeposited material taken from the unpowered electrode. Films were also prepared under the systematic variation of substrate temperature, discharge power, and dilution of the plasma by H2. For the reactor geometry used, dilution of the plasma is found to be essential to the preparation of high-quality a-Ge:H. The conditions for the preparation of optimized a-Ge:H material were quite different from those found to produce optimized a-Si:H in this reactor. We assert this to be the principal cause of the finding of inferior properties for a-SiGe:H alloys when compared with a-Si:H.
Frequency Response of Fluid Lines With Turbulent Flow

A single boundary layer model to account for transient viscous effects is applied to small amplitude sinusoidally disturbed turbulent flow in a tube. The viscous dissipation is calculated using a transfer function relating the local boundary layer velocity gradient to the core velocity. A simple expression for the attenuation factor is derived and the analytical results are shown to be in excellent agreement with previously reported experimental data.
Changes in proenkephalin gene expression in the developing hamster.

Abstract Proenkephalin (Penk) gene expression is high in the adult hamster adrenal medulla and it is comparable to that found in both the hamster and rat striatum. In addition, Penk gene expression in the hamster adrenal medulla is more typical of adult mammalian adrenals than the rat. Since the nature of Penk gene expression in the developing hamster adrenal is not known, it was examined and compared to that found in the striatum were adult levels in the adrenal and striatum are similar. The results show that Penk gene expression progressively increases in the developing hamster adrenal to peak on postnatal day 4. There is then a small decline to adult levels by postnatal day 12 when the morphology of the developing adrenal resembles the adult. Functional splanchnic nerve activity, as assessed by the ability of reserpine to induce increases in adrenal tyrosine hydroxylase mRNA, is not present until after postnatal day 4. Therefore, early increases in Penk gene expression are independent of splanchnic nerve activity. Adrenal EC peptides resulting from the developmental increases in Penk gene expression appear to be unprocessed and proenkephalin-like. This is based on the very low levels of free enkephalin (met-enkephalin) detected in the adrenals from both newborn and adult hamsters (1–5% of total EC peptide levels). In the developing hamster striatum, Penk gene expression remains low and unchanged until postnatal day 4 and increases six-fold by adulthood. Free enkephalin (met-enkephalin) levels remain high (between 36 and 88% of total EC peptide levels) in the developing and adult hamster striatum. Therefore the results show early increases in adrenal Penk gene expression in the developing hamster that are independent of splanchnic nerve activity and adult Penk gene expression which is high and dependent on splanchnic nerve activity. This differs from what is observed in the frequently studied rat. However, developmental changes in the hamster striatum are similar to those in the rat.
The Z Proteins of Pathogenic but Not Nonpathogenic Arenaviruses Inhibit RIG-i-Like Receptor-Dependent Interferon Production

Arenavirus pathogens cause a wide spectrum of diseases in humans ranging from central nervous system disease to lethal hemorrhagic fevers with few treatment options. The reason why some arenaviruses can cause severe human diseases while others cannot is unknown. We find that the Z proteins of all known pathogenic arenaviruses, lymphocytic choriomeningitis virus (LCMV) and Lassa, Junin, Machupo, Sabia, Guanarito, Chapare, Dandenong, and Lujo viruses, can inhibit retinoic acid-inducible gene 1 (RIG-i) and Melanoma Differentiation-Associated protein 5 (MDA5), in sharp contrast to those of 14 other nonpathogenic arenaviruses. Inhibition of the RIG-i-like receptors (RLRs) by pathogenic Z proteins is mediated by the protein-protein interactions of Z and RLRs, which lead to the disruption of the interactions between RLRs and mitochondrial antiviral signaling (MAVS). The Z-RLR interactive interfaces are located within the N-terminal domain (NTD) of the Z protein and the N-terminal CARD domains of RLRs. Swapping of the LCMV Z NTD into the nonpathogenic Pichinde virus (PICV) genome does not affect virus growth in Vero cells but significantly inhibits the type I interferon (IFN) responses and increases viral replication in human primary macrophages. In summary, our results show for the first time an innate immune-system-suppressive mechanism shared by the diverse pathogenic arenaviruses and thus shed important light on the pathogenic mechanism of human arenavirus pathogens. IMPORTANCE We show that all known human-pathogenic arenaviruses share an innate immune suppression mechanism that is based on viral Z protein-mediated RLR inhibition. Our report offers important insights into the potential mechanism of arenavirus pathogenesis, provides a convenient way to evaluate the pathogenic potential of known and/or emerging arenaviruses, and reveals a novel target for the development of broad-spectrum therapies to treat this group of diverse pathogens. More broadly, our report provides a better understanding of the mechanisms of viral immune suppression and host-pathogen interactions.
Decapping Goes Nuclear

In this issue of Molecular Cell, Brannan et al. (2012) propose a novel function for RNA-decapping and transcription termination in aborting "divergent" promoter-proximal elongation complexes.
Purification, Photoaffinity Labeling, and Characterization of a Single Enzyme for 6-Sulfation of both Chondroitin Sulfate and Keratan Sulfate (∗)

A soluble sulfotransferase that could 6-sulfate both chondroitin sulfate and corneal keratan sulfate was purified 27,500-fold using a sequence of affinity chromatographic steps with heparin-Sepharose, wheat germ agglutinin-agarose, and 3′,5′-ADP-agarose. The essentially pure enzyme had a specific activity 40 times greater than the most purified chondroitin 6-sulfotransferase previously reported and exhibited a single sharp Coomassie Blue-stained and a heavy silver-stained protein band of 75 kDa on SDS-polyacrylamide gel electrophoresis. Chromatography of the purified enzyme on Sephacryl demonstrated a size of 150 kDa, which indicated that the native enzyme exists as a dimer. In addition to 6-sulfation of nonsulfated GalNAc, the purified serum enzyme had the ability to sulfate GalNAc 4-sulfate residues to give GalNAc 4,6-disulfate residues. The purified enzyme exhibited a Km of 40 μM for adenosine 3′-phosphate 5′-phosphosulfate when either chondroitin sulfate or corneal keratan sulfate were used as the acceptors. Use of both chondroitin sulfate and keratan sulfate in the same experiment demonstrated mutual competition, establishing that the sulfation of these substrates is by the same enzyme. Photoaffinity labeling of the purified enzyme with 2-azidoadenosine 3′,5′-di[5′-32P]phosphate occurred only with the 75-kDa protein, confirming that this is the chondroitin 6-sulfotransferase/keratan sulfotransferase.
Carbon-13 in tree-ring cellulose as an indicator of past climates

Following Urey's suggestion1 that the 13C abundance (usually expressed as a relative ratio: 13C/12C or δ13C) fixed in plant carbon may be temperature dependent, several authors have investigated the relationship between δ13C and climate. These workers searched for a coefficient relating δ13C variations to temperature variations2–7. The results, obtained on field collected samples, failed to yield agreement about the extent of a climatic effect or even its existence. Growth chamber experiments, performed on different plant species in controlled conditions to eliminate environmental factors other than temperature, showed no clear relationship between δ13C and temperature8,9. These various contradictory results suggest that factors other than temperature contribute to determining δ13C in plants. We now present evidence that the variations of the relative abundance of stable isotopes of carbon in tree rings indicate past climate changes. Thus carbon isotope composition appears to be a proxy indicator that may help to extend the meteorological data base into pre-instrument times.
Feature-based cellular texturing for architectural models

Cellular patterns are all around us, in masonry, tiling, shingles, and many other materials. Such patterns, especially in architectural settings, are influenced by geometric features of the underlying shape. Bricks turn corners, stones frame windows and doorways, and patterns on disconnected portions of a building align to achieve a particular aesthetic goal. We present a strategy for feature-based cellular texturing, where the resulting texture is derived from both patterns of cells and the geometry to which they are applied. As part of this strategy, we perform texturing operations on features in a well-defined order that simplifies the interdependence between cells of adjacent patterns. Occupancy maps are used to indicate which regions of a feature are already occupied by cells of its neighbors, and which regions remain to be textured. We also introduce the notion of a pattern generator — the cellular texturing analogy of a shader used in local illumination — and show how several can be used together to build complex textures. We present results obtained with an implementation of this strategy and discuss details of some example pattern generators.
Crystallization of lithium metasilicate from lithium disilicate glass

The crystallization behavior of lithium disilicate glass powder heated in molten LiNO3 salt was investigated using X-ray diffraction techniques. Heat treatment at 500°C with LiNO3 molten salt caused a lithium metasilicate, Li2SiO3, crystal phase to appear after 5–96 h. By contrast, glass powder heat-treated in air at 500°C remained amorphous after 5 h and turned into lithium disilicate, Li2Si2O5, crystal after 40 h. Qualitatively similar results were obtained at 400°C. Glass powder heat-treated at 575°C in both molten salt and in air turned into lithium disilicate crystal. Metasilicate crystallization occurs with LiNO3 molten salt at 500 and 400°C due to the incorporation of lithium into the sample glass powder from the melt during crystallization. An increase in lithium content in the sample after molten salt heat treatment was confirmed by chemical analysis using dc plasma emission spectroscopy.
Experimental parameters and a biological standard for acridine orange detection of drug-induced alterations in chromatin condensation.

We investigated a number of sample-preparative parameters for use of flow cytometry to detect chromatin condensation in cells stained with acridine orange after DNA in situ is partially denatured by acid treatment. Stability and data reproducibility for both control and drug-treated ME-180 and HT-29 cells were assessed over: a range of cell concentrations in 2.56 X 10(-5) M acridine orange; 15 days of storage in fixative; various times between RNase digestion and staining; and increasing times between staining and analysis. Listmode data for red and green fluorescence were collected and mean fluorescence intensities of G1, S, and G2 subpopulations of HT-29 and ME-180 cells were computed. These were normalized to data from HeLa-S3 cells and fluorescent microspheres to control for inter-experiment variations in staining and instrumental parameters, respectively. The normalized red and green fluorescence data were used to calculate alpha 1 for G1 cells [alpha t = red fluorescence/(total fluorescence)]. Exponentially growing HeLa-S3 cells were a very consistent and reproducible biological standard to control for fixation and staining variability. Mean fluorescence intensities of control and difluoromethylornithine-treated (i.e., polyamine depleted) cells remained stable and reproducible across all tested ranges for cell concentration, storage in fixative, and time after RNase digestion. This technique can thus be used to evaluate difluoromethylornithine-induced changes in chromatin condensation of samples stored for as long as 2 weeks and analyzed all on 1 day.
Discrimination of grain-size subpopulations in pyroclastic deposits

A cubic spline curve fit to histograms of grain-size data from pyroclastic deposits affords a rapid means to distinguish subpopulations in complex size distributions. Using interactive microcomputer graphics, the operator can isolate and quantitatively characterize subpopulations by a method of successive Gaussian subtractions. Percentile measures of the entire size range are not needed, and segments of the whole size distribution can be analyzed independently. Recurrent subpopulations with similar means and standard deviations are consistent among the more than 140 samples of pyroclastic-surge deposits from Sugarloaf in Arizona and Vulcano in Italy. The entire data set can be replicated by synthetic curves consisting of various proportions of five identified Gaussian components, each of which the authors attribute to a specific mechanism of transport and deposition.
Internal Waves and Upwelling of Oceanic Water from Mid-depths on to a Continental Shelf

IN January 1947 at a time when the winter maximum for inorganic phosphate dissolved in the sea is usually reached, a series of observations was made in the western English Channel. In an area north of the coast of Brittany in water of 35.40–35.45%o salinity, temperature about 1o C. higher than in the surrounding water and a zooplankton community typicalof 'south-western' water1, phosphate around 0.40 mgm.-atom/m.3 P was found. If, as appears probable, this is typical of Atlantic surface water at midwinter, the 'Channel' (setosa)1 water, characterized by the presence of the chaetognath, Sagitta setosa, which has occupied the English Channel in the neighbourhood of Plymouth since 1930–31 and has similar maximum phosphate content (0.42–0.48 mgm.-atom/m.3 P), may well have been derived from it. We should, however, have to look elsewhere for the origin of the higher phosphate content (0.6–0.7 mgm.-atom) of the 'elegans' or 'western' water1 of the Celtic Sea, which in the nineteen twenties also filled the western end of the English Channel. The most probable source is upwelling of deeper ocean water from the continental slope. Such upwelling may be attributed to off-shore winds, which would need to be from the north and east. South-westerlies are the prevailing winds of the area both in direction and strength, and the winds from the northern and eastern sectors would, in general, seem not to blow hard enough or long enough to produce upwelling on the scale required. Periods of prolonged fresh easterly winds such as February 1947 are rather exceptional.
Regional Specificity Of Ethanol and NMDA Action in Brain Revealed With FOS‐Like Immunohistochemistry and Differential Routes of Drug Administration

Background: Inhibition of NMDA receptor function in brain is believed to be an important action of ethanol (EtOH). To investigate EtOH inhibition of NMDA receptor responses in vivo, the interaction of these agents in brain after different routes of administration were investigated by using transcription factor Fos protein expression to follow NMDA receptor activation and EtOH inhibition of this response. Methods: The induction of Fos-like immunoreactivity (Fos-LI) in 38 regions of the rat brain was measured 2 hr after treatment with NMDA, EtOH, or both. To determine the relative contribution of abdominal drug effects on Fos induction, rats received either intraperitoneal (ip) or intragastric (ig) EtOH and ip or intravenous (iv) NMDA. Rats received EtOH (2.5 g/kg ip or 4 g/kg ig) or vehicle 15 min before NMDA (125 mg/kg ip or 60 mg/kg iv) or vehicle. Results: For the 38 forebrain regions examined, ip and iv NMDA significantly induced Fos-LI in 13 and 32 regions, respectively. These effects occurred without elicitation of tonic-clonic seizure activity and were strong after iv NMDA in the frontal, prefrontal, and cingulate cortices, supraoptic nucleus, anterior lateral septum, and dentate gyrus. For EtOH, prominent Fos-LI induction was found in the central amygdala, dorsolateral bed nucleus of the stria terminalis, Edinger-Westphal nucleus, and paraventricular hypothalamus. Despite ip and ig EtOH induction of Fos-LI in these regions, the major effect of EtOH was to block NMDA-induced Fos-LI in 8 of 13 (ip) and 27 of 32 (ig) of the NMDA-positive regions, respectively, including retrosplenial, cingulate, and medial prefrontal cortices, central amygdala, and taenia tecta. Conclusions: These results provide new evidence for the regionally specific functional interactions of EtOH on NMDA receptors in vivo. Moreover, these results support efforts to identify brain region–specific targets for EtOH and EtOH-induced changes in gene expression.
Surface phonons for the (001) face of lithium flouride

Abstract Surface phonon branches for the (001) face of LiF have been calculated with a shell model a fifteen-layer film. The “Lucas” TO surface-mode frequency at q = 0 is approximately equal to that of a small unexplained dip in IR transmittance of a thin LiF film as observed by Berreman.
IRON AND SULFUR RELATED COLORS IN ANCIENT GLASSES

Roman glass found at Jalame, in Western Galilee, and dating from the fourth century A.D., shows a variety of colors ranging from aqua blue to green to amber. It was found that the glasses are quite reduced and that the colors arise from absorptions by Fe2+ and a ferri-sulfide chromophore. Small amounts of colorless and purple glass, which had been oxidized by adding MnO2, were also found.
Indonesia's developing forest industry

Indonesia is a major exporter of tropical hardwoods. The country's goal is to establish integrated wood industries by reducing the export of unprocessed sawlogs. The value of hardwood sawlog exports has decreased by twothirds in 1986 dollars since 1978, while the value of hardwood sawnwood and plywood exports has increased sixfold. Sawlog exports are now banned. This article contrasts the official governmental policy on forest industry development with the operational realities of doing business in Indonesia.
The effect of diphenylhydantoin (Dilantin) on thallium-201 chloride uptake.

The effect of diphenylhydantoin (Dilantin) on the myocardial uptake of 201Tl-chloride was studied in rats. Prior administration of Dilantin caused a significant (38.8) decrease in 201Tl uptake compared with the control group. No significant change in heart to blood or heart to muscle ratios was observed. Administration of Dilantin after 201Tl-chloride did not affect the myocardial concentration of the radionuclide.
AN INTRODUCTION TO INNOVATION ADOPTION THEORIES FOR THE DESIGN OF A PRODUCT FAMILY INFORMATION MANAGEMENT INFRASTRUCTURE

As new computer technologies emerge for the design and development of product platforms, applied theories of innovation diffusion and technology acceptance will become increasingly important for securing user cooperation with an information management system for product families. Incorporation of human factors therein will shorten the time required to reach return on investment and increase the depth and breath of information. The history of innovation adoption theories are explored and extended to include commercially available enterprise management software and the proposed product family infrastructure. Six practices, which can be included in the infrastructure in its experimental stages, are described for improving user likelihood of adoption. One efficient way to reuse design knowledge is by leveraging product platforms. Robertson and Ulrich define a product platform as “the collection of assets [i.e., components, processes, knowledge, people and relationships] that are shared by a set of products” [5]. They point out that “by sharing components and production processes across a platform of products, companies can develop differentiated products efficiently, increase the flexibility and responsiveness of their manufacturing processes, and take market share away from competitors that develop only one product at a time” [5]. An effective product platform strategy puts stress on engineers, though, to recognize and capitalize on those elements. It requires both hindsight to examine previously successful products and foresight to predict the shape and appeal of similar products in the future.
Does time have value? An empirical examination of the put option embedded in refundable U.S. air fares

The unprofitable history of the airline industry raises questions about how effectively airlines price their product. In this study, we use option pricing theory to examine the value of the put option embedded in refundable airline tickets. Specifically, we examine whether the time to expiration of the embedded put option is properly priced. Compiling daily real-time ticket price data for Delta and Southwest over 3.5 months, we find little evidence to suggest that airlines price the value of time in the embedded put option. However, we do find evidence suggesting that options are priced higher on business-dominated routes than on vacation-dominated routes.
Destruction of Aqueous-Phase Carbon Tetrachloride in an Electrochemical Reactor with a Porous Cathode

In this work we investigate the use of a continuous-flow, laboratory-scale electrochemical reactor for the destruction of aqueous-phase carbon tetrachloride (CT). The reactor consists of a porous copper foam cathode and a carbon-cloth anode section located downstream from the cathode. Experimental results show that appreciable conversions of CT can be obtained in the reactor, as long as the electrical conductivity of the liquid exceeds 1 S/m. At lower conductivities, most of the cathode exhibits low reactivity for CT-destruction due to relatively low charge transfer overpotentials. A mathematical model was formulated to predict reactor performance. The model takes into account the CT-reduction reaction and the hydrogen evolution reaction on the cathode surface as well as mass transfer limitations. Using the equilibrium potential for CT reduction as the only adjustable parameter, the model adequately represents experimental data for highly conductive solutions.
Demand uncertainty, competition, and ‘non-binding’ price controls

Abstract In our paper, we will present a general model that demonstrate that a price floor or a price ceiling, although not effective at the existing market price, nevertheless alters the competitive equilibrium and leads to erroneous policy conclusions.
Depth distribution of developing Euphausia superba embryos, predicted from sinking rates

Sinking rates of the embryos of Euphausia superba were measured during development in the laboratory at Palmer Station. Antarctic Peninsula, during austral summer 1982. Two densities of seawater were used in these experiments; the lower density (1.027 g cm-3) is characteristic of the upper 300 m of the water column, the higher (1.029 g cm-3) is characteristic of the deeper “circumpolar deep water”. During development, the eggs sank at an initial average rate of 175 m d-1, declining to 51 m d-1 during the gastrula to early limb bud stages and increasing before hatching to near initial rates. The larvae hatched within 6 d. We predict that the majority of the embryos of E. superba should hatch at a depth of about 850 m.
Excitation of Molecular Material near the Young Stellar Object LkHα 234 in NGC 7129

With the Spitzer Infrared Spectrograph (IRS) we have obtained the first mid-IR spectroscopy of NGC 7129, in the unusually strong outflow and in a ridge of H2 emission near the Herbig Be star LkHα 234. The UV radiation field strength is estimated from polycyclic aromatic hydrocarbon (PAH) band intensities in the H2 ridge and found to be comparable to that of NGC 7023. From the rotational H2 emission lines we have deduced aperture average excitation temperatures and column densities in the two regions, finding the H2 ridge values to be consistent with pumping by UV fluorescence, but also comparable to warm-gas regions of Cep A that form H2 in nondissociative C-shocks. The H2 emission in the outflow is consistent with formation by collisional excitation in J-shocks, with shock velocities of 10-30 km s-1. A photodissociating component may be present in the outflow, by similarity of S(0) line intensities in both regions. There is no indication of warm dust in the outflow. We also present the first 16 μm imaging of a Galactic nebula using the unique imaging capabilities of the IRS, combined with ground-based 2.12 μm [H2 1-0 S(1)] imaging. Candidate pre-main-sequence objects are clearly evident in these data. We also find extended emission not previously observed around the young B star BD +65°1638, ~22'' across, showing that the region is not free of material, as otherwise inferred by recent high angular resolution mapping at submillimeter wavelengths. The presence of this material complicates interpretation of the surrounding CO cavity and origin(s) of the photodissociated region, and further spectroscopic observations are needed to characterize its nature.
Tetrakis N-Dimethylaminoethylene is an Extraordinarily Sensitive Reagent for Oxygen

Abstract Tetrakis N-dimethylaminoethylene (TMAE) has been evaluated as a reagent for chemiluminescene (CL) determination of oxygen. The experimental setup is designed so that oxygen diffuses across a membrane to react with TMAE yielding CL. The signal for 100% oxygen using a TFE Teflon membrane with an area of 5 cm2 and 1.5 mls of pure TMAE is nine orders of magnitude greater than the detector noise. In the presence of 100% oxygen, the signal decreases due to TMAE consumption with a half-life of about six hours. The time to reach steady state response when oxygen levels change is less than a minute. A variety of membranes and reagent formulations have been evaluated in attempts to increase the duration of CL and to improve the response time.
Recovery Frequency of Phytophthora ramorum and Other Phytophthora spp. in the Soil Profile of Ornamental Retail Nurseries.

ABSTRACT We tested the hypothesis that inoculum of the aboveground exotic plant pathogen Phytophthora ramorum would be limited to the organic layer (top layer of plant debris) of soils at infested retail nurseries located outside of the area where the pathogen has become established in the landscape. To test this hypothesis and compare inoculum levels of P. ramorum with levels of other Phytophthora spp. in the soil profile, soil cores were collected and sampled from three Washington State retail nurseries at which the soil had previously tested positive for P. ramorum. Phytophthora was isolated from soil using rhododendron leaves as bait, and pure cultures were obtained and stored on V8 juice agar. Isolates were identified to species using a combination of DNA sequencing of the internal transcribed spacer (ITS) region of rDNA, real-time polymerase chain reaction (PCR) diagnostic testing, and culture morphology. Recovery frequencies were tabulated and compared by species at the organic layer, 0 to 5 cm, 5 ...
Efficient parallel algorithms for path problems in directed graphs

In this paper we describe a technique for finding efficient parallel algorithms for problems on directed graphs that involve checking the existence of certain kinds of paths in the graph. This technique provides efficient algorithms for finding dominators in flow graphs, performing interval and loop analysis on reducible flow graphs, and finding the feedback vertices of a digraph. Each of these algorithms takesO(log2n) time using the same number of processors needed for fast matrix multiplication. All of these bounds are for an EREW PRAM.
Elevated homocyst(e)ine levels with preeclampsia

Objective: To determine whether homocyst(e)ine, a relatively new risk factor for possible endothelial cell dysfunction and premature vascular disease, is elevated in nulliparous pregnant women with preeclampsia. Methods: We measured plasma homocyst(e)ine, folic acid, and vitamin B 12 levels in 40 nulliparas, 20 with and 20 without preeclampsia at the time of their delivery. Results: Mean (±standard deviation) plasma homocyst(e)ine levels in the 20 nulliparous women with preeclampsia were significantly higher than in the 20 nulliparous women without preeclampsia (8.66 ± 3.05 versus 4.99 ± 1.11 μ mol/L, P 12 concentrations were not significantly different between the two groups. Conclusion: Homocyst(e)ine levels are elevated in pregnant nulliparas with preeclampsia at the time of their delivery. Further studies are necessary to determine what role homocyst(e)ine may play in the etiology of preeclampsia.
Nonlinear unstable wave disturbances in fluidized beds

Instabilities in fluidized beds are interpreted from the two-phase continuum theory of linearized hydrodynamic stability as the result of interactions between wave hierarchies for which the stability condition is violated; that is, in which the lower-order waves propagate at speeds exceeding those of the higher-order waves. For weak nonlinearities a hierarchy of Burgers-like equations is obtained. The nonlinear modifications to the wave speeds point towards the restoration of the stability condition in the linearized sense. A weakly nonlinear hydrodynamic stability analysis yields an amplitude equation that is of second order. It is argued, however, that the major history of the disturbance development may be expressed by a simpler first-order amplitude equation. The Landau-Stuart constant obtained is intimately related to the nonlinear modifications of the wave speeds of the higher- and lower-order wave operators. It is shown that for supercritical disturbances, amplitude and phase velocity equilibration is possible, and that the levels of the equilibration depend on the initial amplification rate, in agreement with observations. The equilibration occurs by cascades of the fundamental wave disturbance into its harmonics.
Selective localization of C atrial natriuretic peptide receptors in the rat brain.

Abstract We studied the distribution of C atrial natriuretic peptide (C-ANP) receptors in the rat brain after incubation with 125 I-rANP, and competition with the selective C-ANP receptor competitor C-ANP(4–23) (10 −6 M). C-ANP receptors were selectively localized to a few structures, the external plexiform layer of the olfactory bulb, the arachnoid mater and the choroid plexus, and their amount corresponds to 25%, 75% and 35%, respectively, of the ANP specific binding. These data suggest specialized functions for C-ANP receptors in brain.
Determination of the high frequency viscoelastic properties of polymers using shear mode strip delay lines

A recently developed technique for measuring the high frequency shear mechanical properties of a wide range of samples is discussed. The technique involves the propagation of a shear wave in a thin strip of metal. When a sample coating is applied to the metal, the attenuation of the wave in the strip increases and the velocity decreases slightly. Previously, an expression was developed for the relationship between these changes in the wave and the mechanical properties of the sample; however, a simplified derivation is presented here for the special case where the sample is a liquid. At present the method has been used only at 2 MHz, but it can be adapted to frequencies between 1 MHz and 20 MHz quite easily and with careful work to frequencies outside this range. The sensitivity of the technique makes it possible to measure a range of samples extending from liquids with viscosities of only a few centipoise to deformable solids and in some cases rigid solids.
Heat transfer and gas holdup in a two-phase bubble column: air-water system: review and new data

Abstract Hydrodynamic and heat transfer investigations on an air-water system in a bubble column are reported and discussed. Gas holdup data (total and local) and the heat transfer coefficient between a 19 mm outer diameter heat transfer probe and an air-water dispersion are measured in continous and semibatch mode. In addition to new data, earlier data of Saxena et al and those available in the literature are discussed and employed to assess the available correlations and models for gas-phase holdup and heat transfer coefficient. Simple approaches based on general theoretical considerations are proposed to correlate gas holdup and heat transfer data. A few interesting conclusions follow from this study.
Cross-Linking of the DNA Repair Protein O6-Alkylguanine DNA Alkyltransferase to DNA in the Presence of Antitumor Nitrogen Mustards

The antitumor activity of chemotherapeutic nitrogen mustards including chlorambucil, cyclophosphamide, and melphalan is commonly attributed to their ability to induce DNA-DNA cross-links by consecutive alkylation of two nucleophilic sites within the DNA duplex. DNA-protein cross-linking by nitrogen mustards is not well characterized, probably because of its inherent complexity and the insufficient sensitivity of previous methodologies. If formed, DNA-protein conjugates are likely to contribute to both target and off-target cytotoxicity of nitrogen mustard drugs. Here, we show that the DNA repair protein, O (6)-alkylguanine DNA alkyltransferase (AGT), can be readily cross-linked to DNA in the presence of nitrogen mustards. Both chlorambucil and mechlorethamine induced the formation of covalent conjugates between (32)P-labeled double-stranded oligodeoxynucleotides and recombinant human AGT protein, which were detected by SDS-PAGE. Capillary HPLC-electrospray ionization mass spectrometry (ESI-MS) analysis of AGT that had been treated with the guanine half-mustards of chlorambucil or mechlorethamine revealed the ability of the protein to form either one or two cross-links to guanine. C145A AGT (a variant containing a single point mutation in the protein's active site) was found capable of forming a single guanine conjugate, while cross-linking was virtually abolished upon treatment of the C145A/C150S AGT double mutant with the guanine half-mustards. HPLC-ESI (+)-MS/MS sequencing of tryptic peptides obtained from the wild-type AGT protein that had been treated with nitrogen mustards in the presence of DNA confirmed that the cross-linking took place between the N7 position of guanine in DNA and two active site residues within the AGT protein (Cys (145) and Cys (150)). The exact chemical structures of AGT-DNA cross-links induced by chlorambucil and mechlorethamine were identified as N-(2-[ S-cysteinyl]ethyl)- N-(2-[guan-7-yl]ethyl)- p-aminophenylbuyric acid and N-(2-[ S-cysteinyl]ethyl)- N-(2-[guan-7-yl]ethyl)methylamine, respectively, based upon HPLC-MS/MS analysis of protein hydrolysates in parallel with the corresponding amino acid conjugates prepared synthetically. Mechlorethamine-induced AGT-DNA conjugates were isolated from protein extracts of AGT-expressing CHO cells but not control cells, demonstrating that nitrogen mustards can cross-link the AGT protein to DNA in the presence of other nuclear proteins. Because AGT is overexpressed in many tumor types, further investigations of the potential role of AGT-DNA cross-linking in the antitumor and mutagenic activity of antitumor nitrogen mustards are warranted.
Enhanced gravi- and phototropism in plant mdr mutants mislocalizing the auxin efflux protein PIN1

Many aspects of plant growth and development are dependent on the flow of the hormone auxin down the plant from the growing shoot tip where it is synthesized. The direction of auxin transport in stems is believed to result from the basal localization within cells of the PIN1 membrane protein, which controls the efflux of the auxin anion. Mutations in two genes homologous to those encoding the P-glycoprotein ABC transporters that are especially abundant in multidrug-resistant tumour cells in animals were recently shown to block polar auxin transport in the hypocotyls of Arabidopsis seedlings. Here we show that the mdr mutants display faster and greater gravitropism and enhanced phototropism instead of the impaired curvature development expected in mutants lacking polar auxin transport. We find that these phenotypes result from a disruption of the normal accumulation of PIN1 protein along the basal end of hypocotyl cells associated with basipetal auxin flow. Lateral auxin conductance becomes relatively larger as a result, enhancing the growth differentials responsible for tropic responses.
Themes of grief.

A thematic analysis of 30 narrative accounts of bereavement revealed nine themes that included five core themes in bereavement--being stopped, hurting, missing, holding, and seeking; three meta-themes about bereavement--change, expectations, and inexpressibility; and a contextual theme--personal history. The themes were compared with three theoretical perspectives on bereavement by Freud, Kubler-Ross, and one defined as existential-phenomenological. Features of bereavement that are dissimilar or unaddressed by the theoretical perspectives were: (a) the quality of grief's changing character, including "waves" and intense pain which may be triggered years after the death; (b) holding, an individual process of preserving the fact and meaning of the loved one's existence; (c) expectations, both social and personal, as to how the bereaved should be overlaying the experience; and (d) the critical importance of personal history in affecting the quality and meaning of individual bereavement.