cssi/SciSciGPT-SciSciNet huggingface dataset:
Feedback neural networks: new characteristics and a generalization

New characteristics of feedback neural networks are studied. We discuss in detail the question of updating of neurons given incomplete information about the state of the neural network. We show how the mechanism of self-indexing for such updating provides better results than assigning ‘don't know’ values to the missing parts of the state vector. Issues related to the choice of the neural model for a feedback network are also considered. Properties of a new complex valued neuron model that generalizes McCulloch-Pitts neurons are examined.
YOUTH CRIME IN POSTINDUSTRIAL SOCIETIES An Integrated Perspective

Taking a few well-known facts about youth crime, the authors propose a more comprehensive theoretical framework, synthesizing other theories and attempting to describe the link between macro- and microdeviance analysis. Employing Durkheim's concepts of social integration, it is proposed that integration be viewed through patterns of role relationships. When adolescents have meaningful kin, community, educational, and work role relationships, they become socialized to the dominant norms. Conditions in the structural level of society affect the nature and quality of these relationships. Youth crime is specifically related to the salience of the peer relationships and the structural conditions imposed by the society on youth.
A Comparative Study of Measures of General Anxiety and Death Anxiety among Three Medical Groups Including Patient and Wife

A problem not yet extensively researched among hemodialysis patients and their families concerns matters of dying and death. This paper presents a comparative study of general and death anxiety amo...
The Electric Strain Gauge

MANY new developments have grown out of the vibration recorder1 originally described before the AIEE in 1926. One of the first of these developments resulted in apparatus for recording transient pressures electrically.4 This has been used to measure transient pressures in switchgear apparatus, transformers, water wheels, steam turbines, gasoline engines, refrigerators, and in other places. Another is the electric gauge8,18 which has many applications. It is used for the most accurate gauging of production parts in machine shops and inspection rooms, also it is widely used in steel mills for continuous gauging of strips as they are being rolled, for controlling their thickness, for measuring the tension in the strip19 and the pressure applied to the mill rolls. Another application is the measurement of the thickness of paint, enamel, or other nonmagnetic coatings over steel.13
Phase-contrast MRI and applications in congenital heart disease

A review of phase-contrast magnetic resonance imaging techniques, with specific application to congenital heart disease, is presented. Theory, pitfalls, advantages, and specific examples of multiple, well-described congenital heart disease presentations are discussed.
Dehancement of impurity and self-diffusion in niobium by tungsten additions.

The strong curvature found in the Arrhenius plots for self-diffusion in most of the bcc refractory metals has been explained in terms of separate high- and low-temperature mechanisms of diffusion. The low-temperature mechanism appears to be a monovacancy mechanism, but the high-temperature process is not understood. The present experiments have measured the diffusion coefficients of $^{95}\mathrm{Nb}$, $^{95}\mathrm{Zr}$, and $^{185}\mathrm{W}$ in pure niobium, Nb--2 at. % W, Nb--5 at. % W, and Nb--10 at. % W at 2680 K, where 90% of the diffusion occurs by the high-temperature process. The addition of tungsten to niobium equally lessens the diffusion of each of the three isotopes. The dehancements are shown to be due to the overall effect of alloying and not a local interaction effect. Possible mechanisms for mass transport at high temperatures are discussed.
Entwicklungsrichtungen in der Anwendung sauerstoffionen-leitender Festelektrolyte†

In bestimmien Mischoxiden, z. B. ZrO2 dotiert mit Oxiden des Calciums, Magnesiums, Yttriums oder der Seltenen Erden, wird bei erhohter Temperatur der elektrische Strom ausschlieslich uber hochbewegliche Sauerstoff-Ionen transportiert. In einer elektrochemischen Kette bilden derartige Festelektrolyte eine fur Sauerstoff-Ionen elektrochemisch semipermeable Wand. Die Moglichkeiten zur Ausnutzung dieses Effekts in der Technik, z. B. fur Sauerstoff-Mesgerate, Brennstoffzellen, coulometrische Dosierung, Sauerstoff-Gewinnung, Wasserstoff-Gewinnung durch Wasserdampf-Elektrolyse, Sauerstoff-Pumpe und -Konzentrator, elektrolytische Desoxidation und Schmelzflus-Elektrolyse, werden anhand der neuesten Entwicklungen beschrieben.
Hybrid energy sources for embedded sensor nodes

In this paper, we present a series of hybrid energy configurations that are designed to provide a robust power source for embedded sensing hardware. The proper management of energy resources is a critical component in the design of any deployed sensing network. For systems that are installed in remote or inaccessible locations, or those with an operational lifespan that exceeds traditional battery technologies, energy harvesting is an attractive alternative. Unfortunately, the dependence on a single energy source (i.e. solar) can cause potential problems when environmental conditions preclude the system from operating at peak performance. In this paper we consider the use of a hybrid energy source that extracts energy from multiple sources and uses this collective energy to power sensing hardware. The sources considered in this work include: solar, vibration, thermal gradients, and RF energy capture. Methods of increasing the efficiency, energy storage medium, target applications and the integrated use of energy harvesting sources with wireless energy transmission will be discussed.
TH-E-217BCD-10: The Effect of Model Based Iterative Reconstruction (GE-VEO) on the CT Numbers and Noise of Both Small Lung Nodules and Large Homogeneous (heart and Spongiosa) Regions in an Anthropomorphic Chest Phantom

Purpose: To investigate the effect of Model‐Based Iterative Reconstruction (MBIR) on CT#s and noise (standard deviation, SD) of both nodules and homogeneous regions (heart and vertebra spongiosa) in an anthropomorphic chest phantom. Methods: A Lungman phantom (Kyoto‐Kagaku Co. Japan) was imaged with a GE Discovery CT750 HD CT scanner using our clinical lung nodule protocol (120kVp,80mA,0.5s,1.375:1pitch,1.25mm‐slice,0.625mm‐interval,40%ASIR) and lower dose protocols (20mA and 10mA), different %ASIR (0%,70%), and MBIR (VEO). A variety of 5mm‐diameter simulated nodules (−630HU,100HU,water equivalent, etc.) were placed in the vasculature insert in the phantom. CT#s were measured within 7.9mm2 ROIs at the centers of the nodules and within larger ROIs in the heart and vertebra regions. Results: For nodules, on average, the CT#s are 18HU, 25HU, and 30HU greater for VEO than for 0%, 40% and 70%ASIR, respectively. The ratios of the SDs for VEO to those for 0%, 40% and 70%ASIR are 0.60, 0.77, and 0.93, respectively. For the heart region, the CT#s are independent of %ASIR at a given mA, and the CT#s for VEO are smaller than those for all ASIR blends by 10HU at 10mA, 3HU at 20mA, and 1HU at 80mA. The ratios of the SDs for VEO to those for ASIR blends increase with %ASIR and mA ranging from 0.14 for 0%ASIR/10 mA to 0.47 for 70%ASIR/80mA. Corresponding values in the spongiosa region show similar trends, with CT# differences of 35HU, 12HU, and 2HU, and SD ratios ranging from 0.13 to 0.40. Conclusions: The effect of MBIR on mean CT#s and noise depends on object size. The CT#s are greater for MBIR than ASIR blends in nodules; whereas, they are smaller for MBIR in large homogeneous regions. The noise is almost always lower for MBIR, but the degree of smoothing is much greater in large homogeneous regions than in small nodules
A Practical Guide to Groundwater and Solute Transport Modeling

Discussing a book's appendices is a somewhat odd way to begin a book review. However, Appendix A in A Practical Guide to Groundwater and Solute Transport Modeling by Spitz and Moreno provides not only a concise overview of the steps involved in a groundwater modeling study, but also a good starting point to discuss why this text would be a valuable addition to a groundwater modeler's library. The general approach to modeling that Spitz and Moreno take can be found in many groundwater modeling books. However, one rarely finds a text that covers each step in the modeling process as well as this one does. This is especially true in three areas: the selection of model input data, the calibration of a model, and the development of model summaries.
Remarks on mass hierarchies from tumbling gauge theories

Abstract The sequential dynamical breaking of gauge theories to yield mass hierarchies is considered. Situations are found where two channels may condense at roughly the same mass scale even though one channel is more attractive in the theory at energies well above this scale. An explanation in terms of the destabilizing contributions of massive gauge bosons is given. Several examples which illustrate this phenomena are discussed.
Beyond the Living Will

Sixty-three residents of a retirement community with living wills were studied to see if more specific planning for, and thus control over, their dying process would decrease their anxiety about death. The experimental group received intervention in the form of counseling and filling out a questionnaire regarding specific treatments (e.g., CPR, feeding tubes), proxy decision making, and other related questions. Results show that the mean death anxiety score for the experimental group decreased, whereas the control group's mean score did not change significantly.
Effects of warm mix asphalt additives on performance properties of polymer modified asphalt binders

This study presents an experimental evaluation for the performance properties of polymer modified asphalt (PMA) binders containing warm mix asphalt (WMA) additives. The PMA binders with the additives were produced using two of the available warm asphalt processes (i.e., Aspha-min and Sasobit) and three PMA binders graded as performance grade (PG) 76-22. The warm PMA binders were artificially short-term and then long-term aged using the rolling thin film oven (RTFO) and pressure aging vessel (PAV) procedures. Superpave binder tests were carried out on the binders through the rotational viscometer (RV), the dynamic shear rheometer (DSR), and the bending beam rheometer (BBR). In general, the results of this research indicated that (1) the addition of the WMA additives into the PMA binders showed positive effects on increasing rutting resistance at high temperature (based on the high failure temperature values from the DSR test); (2) the PMA binders containing the additives were observed to be less resistant ...
Development of robust control law for active buffeting load alleviation of smart fin structures

Aerodynamic buffeting load can lead to premature fatigue damage of aircraft vertical fin structures. This article presents a robust control law development strategy for active buffeting load alleviation of a smart fin structure. The impact of aerodynamic loads on the modeling uncertainties of the smart fin was investigated through extensive wind tunnel tests. Test results revealed that the airflow introduced higher damping ratio and caused frequency shift to the vibration modes. These aerodynamic effects may adversely affect the performance and robustness of active control laws. Based on the observations, the structured singular value synthesis technique was used to develop a robust control law for the smart fin using a truncated baseline dynamic model. A parametric uncertainty block was introduced to account for the changes in the modal parameters of the baseline dynamic model due to the aerodynamic effects. An additive uncertainty block was included to account for the unmodeled higher-order vibration mo...
Using fractal analysis to quantitatively characterize the shapes of volcanic particles

[1] The shapes of volcanic particles reflect numerous eruptive parameters (e.g., magma viscosity, volatile content, and degree of interaction with water) and are useful for understanding fragmentation and transport processes associated with volcanic eruptions. However, quantitative analysis of volcanic particle shapes has proven difficult because of their morphological complexity and variability. Here a newly developed procedure for shape analysis based on fractal geometry is described and tested. Although volcanic particle shapes are not truly fractal, their complexity can be effectively characterized in terms of fractal values (pseudofractal dimensions) reflecting morphological invariance over discrete ranges of scale. Using fractal data produced by dilation of a particle's two-dimensional boundary, a spectrum of fractal dimensions is calculated for each particle by taking the first derivative of the dilation data. Compared with fractal methods that express shape in terms of only one or two fractal dimensions, typically derived from the slope of data on a Richardson plot, this technique results in better discrimination between samples. In addition, use of multiple fractal values allows incorporation of multivariate statistical analysis, further strengthening the differentiating power of the technique. This fractal spectrum technique yields promising results for samples of sideromelane shards from Iceland and is likely to be effective at characterizing other kinds of volcanic particle shapes.
Mass transfer in turbulent flow

Abstract The local mass transfer coefficient in turbulent duct flow was measured using a new experimental technique. The experimental results agreed quite well with a numerical solution to the turbulent diffusion equation in channel flow. Formulation of the diffusion equation provided a continuous solution from a point near the discontinuity in mass flux to the fully developed region. The Nusselt numbers obtained numerically agreed with Spalding's asymptotic solution at x D h and Hatton et al.' seigenvalue solution for symmetrical heat transfer which is valid for x D h > 1 . Current asymmetric heat transfer results in the fully developed region fell between the eigenvalue and numerical solutions.
Saturn's kilometric radiation: satellite modulation

There is an episodic 66-h modulation of the Saturn kilometric radiation which is both frequency and Dione-phase dependent. The behavior is significantly different from the way in which Io modulates the Jovian emission.
Mechanism of the spark breakdown

THE ELECTRIC SPARK was first treated quantitatively by J. S. Townsend in 1903.1 Since that time, the interpretation of the physical processes that lead to breakdown has been modified radically.2–7 It is the purpose of this report to trace the development of the present concepts of the physical processes which lead to the d-c electric spark, and to discuss to what extent these processes are understood.
Induction of CYP1A1 and CYP1B1 in liver and lung by benzo(a)pyrene and 7,12-d imethylbenz(a)anthracene do not affect distribution of polycyclic hydrocarbons to target tissue: role of AhR and CYP1B1 in bone marrow cytotoxicity.

Abstract Polycyclic aromatic hydrocarbons (PAHs) (50 mg/kg, i.p.) selectively deplete mouse bone marrow (BM) hematopoietic cells through a process that is dependent on CYP1B1. 7,12-dimethylbenz(a)anthracene (DMBA), which forms greater amounts of dihydrodiol-epoxide-DNA adducts in BM, is much more effective in depleting BM cells than benzo(a)pyrene (BP). BM toxicity by BP is restored in congenic mice expressing a weakly responsive aryl hydrocarbon receptor (AhR d replaces AhR b ). BP strongly induces CYP1A1 around the hepatic vein whereas DMBA produces a weaker diffuse response, paralleling differences in CYP1A1 protein. These responses are absent in AhR d mice. BP and DMBA broadly and equally induce CYP1A1 in the lung, while CYP1B1 is induced in bronchial blood vessels. In sternum, CYP1B1 is induced in BM and white fat, whereas CYP1A1 is induced only in brown fat. BP and DMBA levels were similar within blood, lung, and BM and did not rise in AhR d mice. In liver, selective decrease of BP was consistent with induced metabolism via CYP1A1, which nevertheless does not determine the blood levels and distribution to BM. Effective delivery of BP to BM is indicated by formation of BP-quinone DNA adducts and the effective induction of CYP1B1. The low formation of BP-dihydrodiol-epoxide-DNA adducts suggests effective AhR induction of BM detoxifying reactions that prevents their formation from dihydrodiols. These findings contrast with the substantial hepatic CYP1A1 contribution for PAHs previously seen for intragastric administration where first pass elimination limits the amount of PAHs reaching the BM.
Detection of polarized light by the homing pigeon, Columba livia

Of 12 homing pigeons tested, four could be trained to discriminate between a linearly polarized light source with a rotating axis of polarization and the same light source with a stationary axis of polarization. Initially, all 12 pigeons were trained to discriminate between rotating and nonrotating crosshairs. The crosshairs were gradually faded until only polarized light remained. The response was a classically conditioned increase in heart rate. An additional control series was performed using neutral density filters. This is the first evidence for polarized light detection in birds.
Pyridoxine (B6)-induced inhibition of prolactin release in the female rat.

The present studies were carried out to determine whether pyridoxine (B6) inhibits PRL release in the rat and to define its site of action. Adult female rats were injected with 50 mg B6 of diluent (C) ip at 1200 h on proestrus. B6 prevented the increase in PRL secretion normally observed at 1300 h and this inhibition was prolonged until at least 1500 h by a second injection of B6 at 1400 h. All B6-treated and control animals had normal proestrous LH surges and ovulated the next day. To determine whether the inhibitory effect of B6 on PRL release was due to enhanced dopamine synthesis or to a direct effect on the pituitary, ovariectomized rats were treated with a potent inhibitor of dopamine synthesis, α-methyl-p-tyrosine (α-MPT). The administration of B6 either with or 4 h after α-MPT significantly decreased the PRL rise observed in animals treated with α-MPT alone. B6 also significantly suppressed the TRH-induced PRL rise in both α-MPTtreated and normal rats, but had no effect on the TRHinduced rise in p...
Metropolitan Housing Segregation in 1980: The St. Louis Case.

Metropolitan patterns of black/white housing segregation are analyzed through the 1980 census data for the St. Louis Metropolitan area. Using the index of dissimilarity as an indicator of segregati...
Ethanol Effects on Embryonic Craniofacial Growth and Development: Implications for Study of the Fetal Alcohol Syndrome

Fetal alcohol syndrome (FAS), which is brought about by maternal consumption of ethanol during pregnancy, is a major public health problem. To gain understanding of the etiology of this condition, a number of teratological studies have been performed in different animal systems to develop an animal model for FAS. The C57BL/6J mouse strain has been described as susceptible to the teratogenic effects of ethanol, whereas the ICR (CD-1) strain is considered relatively insensitive. We have compared the effects of ethanol on DNA and protein synthesis in cultured embryonic palate mesenchymal cells from both strains to determine if the reported differential sensitivity to ethanol is reflected in differences in ethanol's effects on cell behavior. Chronic exposure to 200 mM ethanol for 48 hr had a strong inhibitory effect on DNA synthesis in palate cells derived from both the C57BL/6J and ICR strains and a significant effect on protein synthesis in C57BL/6J palate cells. When we attempted to verify strain differences in susceptibility to ethanol teratogenesis, we were not able to observe an increased incidence of birth defects due to ethanol in either strain. High doses of ethanol (5.8 g/kg, administered by intraperitoneal injection on gestational day 8) resulted in death in both C57BL/6J and ICR mice. A lower dose (4.8 g/kg) caused decreased fetal weight and increased resorption in both strains, but did not bring about FAS-like craniofacial dysmorphology in either strain. It appears, therefore, that whereas ethanol can significantly affect the behavior of cells derived from craniofacial tissue, these effects cannot be correlated with sensitivity to ethanol teratogenesis in the mouse system. In view of these results, we suggest that the suitability of the mouse model for FAS be reviewed.
Microstructures of mercury-based cuprate thin films

Abstract The microstructures of Hg-based cuprate thin films have been studied using a scanning electron microscope and an energy dispersive X-ray spectrometer. Besides a rough surface, several types of defects including the HgCaO 2 phase are identified on those films made using a slow temperature ramping Hg-vapor annealing process. By ramping the sample temperature rapidly to the annealing temperature, the surface morphology of the film is significantly improved and the impurity phases, especially the HgCaO 2 phase, are effectively reduced.
House society and practice theories illuminate American campsteads

House society theory’s experientially grounded flexibility founds an understanding of century-old American campsteads at Squam Lake, New Hampshire. These conjoin five to seven familial generations with place, property, architecture, and memory; foster a sort of experience with conceptual and structural implications for both people and the local landscape. The morphogenic relations between experience, intelligibilia, and structuring conditions, in turn, find a clear theoretical model in Margaret Archer’s practice theory. This article describes such campsteads, locating their emergence and continuing structural importance in cycles of American nature religion. The campstead thus assumes a spiritual mantle, and fosters in campsteaders a self intimately shaped by close experience having heightened personal significance.
Plant-microbe competition for soil amino acids in the alpine tundra: effects of freeze-thaw and dry-rewet events.

Amino acids have been shown to be a potentially significant N source for the alpine sedge, Kobresia myosuroides. We hypothesised that freeze-thaw and dry-rewet events allow this plant species increased access to amino acids by disrupting microbial cells, which decreases the size of competing microbial populations, but increases soil amino acid concentrations. To test this hypothesis, we characterized freeze-thaw and dry-rewet events in the field and simulated them in laboratory experiments on plant-soil microcosms. In one experiment, 15N,13C-[2]-glycine was added to microcosms that had previously been subjected to a freeze-thaw or dry-rewet event, and isotopic concentrations in the plant and microbial fractions were compared to non-stressed controls. Microbial biomass and uptake of the labeled glycine were unaffected by the freezing and drying treatments, but microbial uptake of 15N was lower in the two warmer treatments (dry-rewet and summer control) then in the two colder treatments (freeze-thaw and fall control). Plant uptake of glycine-15N was decreased by climatic disturbance, and uptake in plants that had been frozen appeared to be dependent on the severity of the freeze. The fact that intact glycine was absorbed by the plants was confirmed by near equal enrichment of plant tissues in 13C and 15N. Plants under optimal conditions recovered 3.5% of the added 15N and microbes recovered 5.0%. The majority of the 13C and 15N label remained in a non-extractable fraction in the bulk soil. To better understand the isolated influences of environmental perturbations on soil amino acid pools and population sizes of amino-acid utilizing microbes, separate experiments were performed in which soils, alone, were subjected to drying and rewetting or freezing and thawing. Potential respiration of glycine and glutamate (substrate-induced respiration; SIR) by the soil microbial communities was unaffected by a single freeze-thaw event. Glycine SIR was decreased slightly (∼10%) by the most extreme drying treatment, but glutamate SIR was not significantly affected. Freezing lowered the concentration of water-extractable amino acids while drying increased their concentration. We interpret the surprising former result as either a decrease in proteolytic activity in frozen soils relative to amino acid uptake, or a stimulation in microbial uptake by physical nutrient release from the soil. We conclude that climatic disturbance does not provide opportunities for increased amino acid uptake by K. myosuroides, but that this plant competes well for amino acid N under non-stressed conditions, especially when soils are warm. We also note that this alpine tundra microbial community's high resistance to freeze-thaw and dry-rewet events is novel and contrasts with studies in other ecosystems.
Edaphic environment, gall midges, and goldenrod clonal expansion in a mid-successional old-field

During the middle stage of old-field succession, genets of clonal plants vie to take over space from annual and short-lived perennial plants. We studied factors that may influence the relative rates of expansion of Solidago altissima genets in an old-field population attacked by the gall midge Rhopalomyia solidaginis. Genets growing in more clayey soil expanded more slowly, as evidenced by differences in rhizome growth. Edaphic conditions also affected galling frequencies, with genets in more sandy soil having twice as many galls. Gall midges reduced goldenrod stem growth, and stem height was positively correlated with rhizome growth. For a given stem height, galled ramets allocated relatively more biomass to rhizome growth than ungalled ramets. The end result was that galled ramets produced the same number and sizes of rhizomes as ungalled ramets.
Parasitic Gaps licensed by elided syntactic structure

This study provides an argument for syntactic approaches to sluicing. We base our study on the novel observation that Parasitic Gaps (PG) are licensed in sluicing contexts. We show that, in order for PGs to be licensed in sluicing contexts, overt wh-movement must occur, leaving a real gap in the ellipsis site. Therefore, the ellipsis site has the full-fledged syntactic structure that licenses PGs.
A Preliminary Study on the Mechanical Performance of Tiled Polymer Composites

We are developing and exploring the concept of in-plane tiling of composite laminates, called MOSAIC, to mitigate or control delamination at free edges due to interlaminar stresses. Initial mechanical testing has shown that MOSAIC composites with uniaxial graphite-fiber reinforced tiles retain the stiffness levels of traditional uniaxially reinforced composites but with reduced strength. The reduction in strength is attributed to the formation of resin-rich pockets between adjacent tiles. In this study, we have performed detailed finite element analyses to identify the critical design parameters that affect the mechanical performance of uniaxially reinforced MOSAIC composites. We have found that using continuous laminae on the outer surfaces significantly increases the overall loadcarrying capacity. Increasing aspect ratio of the pocket and decreasing material property differences between resin and tiles also cause better load transfer between tiles but may not necessarily improve overall strength due to increasing stress concentration. The tiling scheme and density of pocket placement influence the interaction of local stress concentrations. Consequently, a novel composite joint is proposed and found to have superior performance.Copyright © 2006 by ASME
The effect of contextual stimuli on retroactive inhibition

In an A-B, A-C paradigm for investigating retroactive inhibition (RI), two sets of contextual stimuli (colored shapes) surrounded each list. During recall, RI groups were given either the context present during interpolated learning (IL) or the context present during original learning (OL). Through two recall trials but not through relearning (RL), the presence of the OL context reduced RI, while the presence of the IL context increased RI.
Microstructure-Sensitive Fatigue Modeling of AISI 4140 Steel

A microstructure-based fatigue model is employed to predict fatigue damage in 4140 steel. Fully reversed, strain control fatigue tests were conducted at various strain amplitudes and scanning electron microscopy was employed to establish structure-property relations between the microstructure and cyclic damage. Fatigue cracks were found to initiate from particles near the free surface of the specimens. In addition, fatigue striations were found to originate from these particles and grew radially outward. The fatigue model used in this study captured the microstructural effects and mechanics of nucleation and growth observed in this ferrous metal. Good correlation of the number of cycles to failure between the experimental results and the model were achieved. Based on analysis of the mechanical testing, fractography and modeling, the fatigue life of the 4140 steel is estimated to comprise mainly of small crack growth in the low cycle regime and crack incubation in the high cycle fatigue regime.
Interaction of oxidation and crosslinking in gamma-irradiated ultrahigh molecular-weight polyethylene.

The interaction between oxidation and crosslinking in gamma-irradiated ultrahigh molecular-weight polyethylene with and without artificial aging was studied. The effect of the atmosphere during irradiation (air vs. low oxygen) occurred primarily within about 0.5 mm of the surface, that is, the depth to which oxygen had diffused when the polyethylene specimen was machined and when it was irradiated. Irradiation in the presence of oxygen induced oxidation instead of crosslinking, so that the level of crosslinking achieved was lower than that which normally would occur at the same dose in the absence of oxygen. Subsequent artificial aging reduced the gel content (crosslinking) and had a maximal effect on the surface and subsurface regions for the gamma-air and gamma-low oxygen polyethylenes, respectively. Thus the storage environments and durations prior to irradiation and prior to artificial aging must be taken into account when attempting to duplicate the oxidation-crosslinking profiles that occur with actual implants in clinical use. In addition, the oxidation mechanisms initiated by the artificial aging method used in this study (i.e., heating in air to 80 degrees C) initiated somewhat different oxidative reactions from those that occur during prolonged shelf life at room temperature or in vivo. In particular, the formation of a peak of oxidation below the free surface of the polyethylene is due to the combined effects of the distribution of residual free radicals and the diffusion gradient of the oxygen. The interactive relationship between oxidation and crosslinking characterized in the present study provides a fundamental basis for understanding the wear behavior of gamma-sterilized components in past clinical use. It also provides guidelines for the development of polyethylenes with improved resistance to oxidation and wear, with particular relevance to estimation of the amount of crosslinking need- ed to potentially eliminate the clinical problem of osteolysis.
Origins of methane in hydrothermal systems

Abstract Isotopic and compositional evidence indicates that the principal source of methane in most subaerial hydrothermal systems is from thermocatalysis of organic matter (thermogenesis). No firm evidence exists for abiogenic production at hydrothermal temperatures. However, abiogenesis represents the principal methane source in high-temperature rock-dominated mid-ocean-ridge hydrothermal systems, in which methane is derived from the rock itself. The importance of carbon-isotope equilibrium between CH4 and CO2 at hydrothermal temperatures (≤350°C) is in dispute, although in most systems studied, equilibrium at such temperatures appears unlikely. Carbon isotope compositions of methane in high-temperature systems vary from ∼ −50 to -15‰ vs. PDB, with the most negative values occurring in systems with high CH4 abundances, i.e. where thermocatalysis is important. Carbon isotope compositions of coexisting CO2 also decrease with increasing CH4 abundance (or degree of thermogenic input). This coupled carbon isotope variation suggests that high-temperature oxidation and thermocatalytic breakdown of organic carbon compounds are important in many hydrothermal environments. The enrichment of 13C in methane from high-temperature mid-ocean ridge environments is consistent with isotopic equilibrium at very high temperatures (> 500°C) within the host rocks, and supports the concept of methane genesis within the rock prior to hydrothermal extraction. Unusual 13C-enriched methanes are also found in some subaerial geothermal systems, although a rock-derived origin remains speculative in these cases. In light of the existing evidence, it appears that the sources of methane (either thermogenesis from organic carbon or abiogenesis within rocks) are much more important in determining the relative abundance and carbon isotope composition of hydrothermal methane than any subsequent approach to chemical and/or isotopic equilibrium under hydrothermal conditions.
Ultraperformance ion-pair liquid chromatography coupled to electrospray time-of-flight mass spectrometry for compositional profiling and quantification of heparin and heparan sulfate.

Heparin and heparan sulfate (HS) are important pharmaceutical targets because they bind a large number of proteins, including growth factors and cytokines, mediating many biological processes. Because of their biological significance and complexity, there is a need for development of rapid and sensitive analytical techniques for the characterization and compositional analysis of heparin and HS at the disaccharide level, as well as for the structure elucidation of larger glycosaminoglycan (GAG) sequences important for protein binding. In this work, we present a rapid method for analysis of disaccharide composition using reversed-phase ion-pairing ultraperformance liquid chromatography coupled with electrospray time-of-flight mass spectrometry ((RPIP)-UPLC−MS). Heparin disaccharide standards were eluted in less than 5 min. The method was used to determine the constituents of GAGs from unfractionated heparin/HS from various bovine and porcine tissues, and the results were compared with literature values.
Qualitative Sonar Based Environment Learning for Mobile Robots

We present a method for navigation and environment learning based on active sensing using sonar and a compass. The method consists of a set of incrementally designed behaviors for extracting environment features from the sensory data. The features are stored in a totally distributed list of augmented finite state machines which serves as a decentralized world model.
Inhibitory Fc Gamma Receptors: From Gene to Disease

Multiple lines of evidence have revealed a key role for inhibitory Fc gamma receptors class IIb (FcgammaRIIb) as negative modulators of innate and adaptive immune responses. Acquired and genetic factors regulate the expression of FcgammaRIIb receptors and modify their inhibitory potential. Recent advances have highlighted the importance of FcgammaRIIb receptors in influencing the development of cancer and autoimmunity. The association of increased FcgammaRIIb expression with tumor development is believed to operate at effector cell level resulting in inhibition of antitumor cytotoxicity. In autoimmune diseases, FcgammaRIIb receptors play a major role in controlling the amplitude of antibody- and immune complex-mediated reactions. Generally, FcgammaRIIb deficiency is associated with increased susceptibility and severity to organ-specific and systemic autoimmunity. This article discusses the proposed mechanisms for FcgammaRIIb deregulation associated with malignant and autoimmune pathology in animal models and human diseases.
Child Abuse and Neglect: A System That Still Needs Pediatric Leadership

Four decades ago, a group of pediatricians published landmark research that substantiated abuse and neglect as an issue worthy of society's attention, providing the catalyst for cultural change and milestone legislation.1 Although a generation of child advocates has made remarkable progress, children remain at risk, and pediatricians must remain leaders in protecting vulnerable children. Every year in the United States, an estimated 900000 children are determined to be victims of child maltreatment, and more than 1500 die secondary to abuse and neglect. To ensure their safety, every year 800000 American children spend time in foster care. In addition, although the $100 billion annual cost of child abuse and neglect to US society is insignificant when compared with the measure of human suffering, it is not a trivial sum. Included in the August and September issues of Pediatrics are 2 articles about the child abuse identification and reporting behaviors of pediatricians.2,3 The Child Abuse Reporting Experience Study (CARES), conducted by the American Academy of Pediatrics (AAP) Pediatric Research in Office Settings (PROS) Network, has provided evidence-based confirmation of the perceptions of professionals who have spent entire careers evaluating cases of suspected abuse and neglect. CARES investigators found that health care providers do not report all cases of suspected abuse, in large part because of concerns over best outcomes, given a system perceived as dysfunctional. Previous research has suggested that the results of the CARES, although certainly unsettling for pediatricians, seem to be part of a larger and consistent picture of child abuse reporting (or the lack thereof) by professionals who are mandated to report it. For example, in 1994, Tilden et al4 surveyed a wider variety of … Address correspondence to Edward Bailey, MD, NSMC/North Shore Children's, 57 Highland Ave, Salem, MA 01970. E-mail: enbailey{at}partners.org
“Drinking Won't Get You Thinking”: A Content Analysis of Adolescent-Created Print Alcohol Counter-advertisements

Involvement in creating antialcohol advertisements generates enthusiasm among adolescents; however, little is known about the messages adolescents develop for these activities. In this article, we present a content analysis of 72 print alcohol counteradvertisements created by high school (age 14–17 years old) and college (18–25 years old) students. The posters were content analyzed for poster message content, persuasion strategies, and production components, and we compared high school and college student posters. All of the posters used a slogan to highlight the main point/message of the ad and counterarguments/consequences to support the slogans. The most frequently depicted consequences were negative consequences of alcohol use, followed by negative–positive consequence comparison. Persuasion strategies were sparingly used in advertisements and included having fun/one of the gang, humor/unexpected, glamour/sex appeal, and endorsement. Finally, posters displayed a number of production techniques includi...
Low-Temperature Epitaxy of Compressively Strained Silicon Directly on Silicon Substrates

We report epitaxial growth of compressively strained silicon directly on (100) silicon substrates by plasma-enhanced chemical vapor deposition. The silicon epitaxy was performed in a silane and hydrogen gas mixture at temperatures as low as 150C. We investigate the effect of hydrogen dilution during the silicon epitaxy on the strain level by high-resolution x-ray diffraction. Additionally, triple-axis x-ray reciprocal-space mapping of the samples indicates that (i) the epitaxial layers are fully strained and (ii) the strain is graded. Secondary-ion mass spectrometry depth profiling reveals the correlation between the strain gradient and the hydrogen concentration profile within the epitaxial layers. Furthermore, heavily phosphorus-doped layers with an electrically active doping concentration of � 2 9 10 20 cm � 3 were obtained at such low growth temperatures.
Ribosomal Protein L17, RpL17, is an Inhibitor of Vascular Smooth Muscle Growth and Carotid Intima Formation

Background—Carotid intima-media thickening is associated with increased cardiovascular risk in humans. We discovered that intima formation and cell proliferation in response to carotid injury is greater in SJL/J (SJL) in comparison with C3HeB/FeJ (C3H/F) mice. The purpose of this study was to identify candidate genes contributing to intima formation. Methods and Results—We performed microarray and bioinformatic analyses of carotid arteries from C3H/F and SJL mice. Kyoto Encyclopedia of Genes and Genomes analysis showed that the ribosome pathway was significantly up-regulated in C3H/F in comparison with SJL mice. Expression of a ribosomal protein, RpL17, was >40-fold higher in C3H/F carotids in comparison with SJL. Aortic vascular smooth muscle cells from C3H/F grew slower in comparison to SJL. To determine the role of RpL17 in vascular smooth muscle cell growth regulation, we analyzed the relationship between RpL17 expression and cell cycle progression. Cultured vascular smooth muscle cells from mice, rat...
Fast Microtubule Dynamics in Meiotic Spindles Measured by Single Molecule Imaging: Evidence That the Spindle Environment Does Not Stabilize Microtubules

Metaphase spindles are steady-state ensembles of microtubules that turn over rapidly and slide poleward in some systems. Since the discovery of dynamic instability in the mid-1980s, models for spindle morphogenesis have proposed that microtubules are stabilized by the spindle environment. We used single molecule imaging to measure tubulin turnover in spindles, and nonspindle assemblies, in Xenopus laevis egg extracts. We observed many events where tubulin molecules spend only a few seconds in polymer and thus are difficult to reconcile with standard models of polymerization dynamics. Our data can be quantitatively explained by a simple, phenomenological model-with only one adjustable parameter-in which the growing and shrinking of microtubule ends is approximated as a biased random walk. Microtubule turnover kinetics did not vary with position in the spindle and were the same in spindles and nonspindle ensembles nucleated by Tetrahymena pellicles. These results argue that the high density of microtubules in spindles compared with bulk cytoplasm is caused by local enhancement of nucleation and not by local stabilization. It follows that the key to understanding spindle morphogenesis will be to elucidate how nucleation is spatially controlled.
An infinite number of commuting quantum Ŵ∞ charges in the SL(2, R)/U(1) coset model

Abstract The conformal non-compact SL(2, R )/U(1 coset model in two dimensions has been recently shown to embody a non-linear Ŵ ∞ current algebra, consisting of currents of spin ⩾2 including the energy-momentum tensor. In this letter we explicitly construct an infinite set of commuting quantum Ŵ ∞ charges in the model with k =1. These commuting quantum charges generate a set of infinitely many compatible flows (quantum KP flows), which maintain the non-linear Ŵ ∞ current algebra invariant.
Diffusivity of nitrogen in α-iron at high nitrogen potential at 773 k

Abstract The diffusion coefficient of nitrogen in α-Fe has been well-documented in the literature. However such measurements under high nitrogen potentials have rarely been reported. In this investigation, the diffusivity of nitrogen in α-Fe at various high nitrogen potentials, attained by use of hydrogen—ammonia gas mixtures were measured by a thermogravimetric technique.
Optimizing spacecraft reorientation maneuvers using a pseudospectral method

This paper examines the problems of optimal reorientation of a spacecraft for the time-optimal, fuel- optimal, and combined time- and fuel-optimal cases. The solutions are generated via a pseudospectral method, which is shown to perform well for this problem. Comparison with the literature indicates that the time-optimal problem appears in some cases to exhibit multiple local minima, each satisfying the necessary conditions for optimality.
Application of infinite elements to phase change situations on deforming meshes

In recent years progress has been made in applying moving and deforming mesh systems to phase change problems. This allows the numerical attention where it is needed, near the migrating phase change zone. In spatially unbounded problems one hopes that numerically finite outer boundaries either escape significant activity or are automatically pushed further away as activity nears. Not infrequently this approach fails. Temperature activity often spreads more rapidly than phase change, thereby reaching far boundaries; stretching of the mesh by movement of far boundaries can challenge mesh control and cause ill-conditioning. In this paper the advantages of time dependent mesh adaption are enhanced by the joining of a new formulation for infinite elements to far boundaries. This is accomplished through a co-ordinate transformation within the framework of conventional 2-D quadratic, biquadratic, and linear–quadratic elements. Standard 2 by 2 Gauss–Legendre quadrature suffices throughout and normal Galerkin finite element features are undisturbed, including strict conservation of energy. The formulation is independent of global co-ordinates, entails no restrictions on the unknown function and should be applicable to other problem types. All test cases on quadrilateral and triangular grids show very significant improvements with infinite elements relative to comparable solution systems using strictly finite grids.
Agentsheets: a medium for creating domain-oriented visual languages

Customized visual representations enable end users to achieve their programming goals. Here, designers work with users to tailor visual programming languages to specific problem domains. We describe a design methodology and a tool for creating domain oriented, end user programming languages that effectively use visualization. We first describe a collaborative design methodology involving end users and designers. We then present Agentsheets, a tool for creating domain oriented visual programming languages, and illustrate how it supports collaborative design by examining experiences from a real language design project. Finally, we summarize the contributions of our approach and discuss its viability in industrial design projects. >
Surface Enhanced Fluorescence (SEF): Polarization Characteristics

Nanostructured platforms and specifically, array of nanoholes with subwavelength pitch, have been shown to enhance fluorescence signals. Here, we assess the effect of platform orientation with respect to the incident polarized (exciting) beam on the fluorescence signal of dye molecules, imbedded in the pores of such structures. Clear angular-dependent fluorescence signal, excited with the TM mode of the incident laser beam, has been demonstrated. The results may be explained by feedback to the scattered fluorescence mode from the array of nanoholes.
Spanking and Child Development During the First 5 Years of Life

Using data from the Fragile Families and Child Wellbeing Study (N = 3,870) and cross-lagged path analysis, the authors examined whether spanking at ages 1 and 3 is adversely associated with cognitive skills and behavior problems at ages 3 and 5. The authors found spanking at age 1 was associated with a higher level of spanking and externalizing behavior at age 3, and spanking at age 3 was associated with a higher level of internalizing and externalizing behavior at age 5. The associations between spanking at age 1 and behavioral problems at age 5 operated predominantly through ongoing spanking at age 3. The authors did not find an association between spanking at age 1 and cognitive skills at age 3 or 5.