cssi/SciSciGPT-SciSciNet huggingface dataset:
A recommendation for revised dose calibrator measurement procedures for 89Zr and 124I

Because of their chemical properties and multiday half lives, iodine-124 and zirconium-89 are being used in a growing number of PET imaging studies. Some aspects of their quantitation, however, still need attention. For 89Zr the PET images should, in principle, be as quantitatively accurate as similarly reconstructed 18F measurements. We found, however, that images of a 20 cm well calibration phantom containing 89Zr underestimated the activity by approximately 10% relative to a dose calibrator measurement (Capintec CRC-15R) using a published calibration setting number of 465. PET images of 124I, in contrast, are complicated by the contribution of decays in cascade that add spurious coincident events to the PET data. When these cascade coincidences are properly accounted for, quantitatively accurate images should be possible. We found, however, that even with this correction we still encountered what appeared to be a large variability in the accuracy of the PET images when compared to dose calibrator measurements made using the calibration setting number, 570, recommended by Capintec. We derive new calibration setting numbers for 89Zr and 124I based on their 511 keV photon peaks as measured on an HPGe detector. The peaks were calibrated relative to an 18F standard, the activity level of which was precisely measured in a dose calibrator under well-defined measurement conditions. When measuring 89Zr on a Capintec CRC-15R we propose the use of calibration setting number 517. And for 124I, we recommend the use of a copper filter surrounding the sample and the use of calibration setting number 494. The new dose calibrator measurement procedures we propose will result in more consistent and accurate radioactivity measurements of 89Zr and 124I. These and other positron emitting radionuclides can be accurately calibrated relative to 18F based on measurements of their 511 keV peaks and knowledge of their relative positron abundances.
A Stochastic Averaging Approach for Feedback Control Design of Nonlinear Systems Under Random Excitations

This paper presents a method for designing and quantifying the performance of feedback stochastic controls for nonlinear systems. The design makes use of the method of stochastic averaging to reduce the dimension of the state space and to derive the Ito stochastic differential equation for the response amplitude process. The moment equation of the amplitude process closed by the Rayleigh approximation is used as a means to characterize the transient performance of the feedback control. The steady state and transient response of the amplitude process are used as the design criteria for choosing the feedback control gains. Numerical examples are studied to demonstrate the performance of the control.
Chaos and avoided level crossings.

The influence of chaos on tunneling in the quantum phase space of the harmonically driven pendulum is studied herein. We analyze the avoided level crossing between a quasienergy state associated with the chaotic part of the phase space and a member of the nearly degenerate doublet localized on the symmetric Kolmogorov-Arnold-Moser (KAM) islands. As a result of the interaction the quasienergy states ``exchange'' their structure. The initially chaotic state evolves into the regular one and vice versa. This interchange significantly affects dynamical tunneling of wave packets centered on the KAM islands.
Polynomials for classification trees and applications

This paper relates computational commutative algebra to tree classification with binary covariates. With a single classification variable, properties of uniqueness of a tree polynomial are established. In a binary multivariate context, it is shown how trees for many response variables can be made into a single ideal of polynomials for computations. Finally, a new sequential algorithm is proposed for uniform conditional sampling. The algorithm combines the lexicographic Groebner basis with importance sampling and it can be used for conditional comparisons of regulatory network maps. The binary state space leads to an explicit form for the design ideal, which leads to useful radical and extension properties that play a role in the algorithms.
Surveying current research in object-oriented design

The state of object-oriented is evolving rapidly. This survey describes what are currently thought to be the key ideas. Although it is necessarily incomplete, it contains both academic and industrial efforts and describes work in both the United States and Europe. It ignores well-known ideas, like that of Coad and Meyer [34], in favor of less widely known projects.Research in object-oriented design can be divided many ways. Some research is focused on describing a design process. Some is focused on finding rules for good designs. A third approach is to build tools to support design. Most of the research described in this article does all three.We first present work from Alan Snyder at Hewlett-Packard on developing a common framework for object-oriented terminology. The goal of this effort is to develop and communicate a corporate-wide common language for specifying and communicating about objects.We next look into the research activity at Hewlett-Packard, led by Dennis de Champeaux. De Champeaux is developing a model for object-based analysis. His current research focuses on the use of a trigger-based model for inter-object communications and development of a top-down approach to analysis using ensembles.We then survey two research activities that prescribe the design process. Rebecca Wirfs-Brock from Tektronix has been developing an object-oriented design method that focuses on object responsibilities and collaborations. The method includes graphical tools for improving encapsulation and understanding patterns of object communication. Trygve Reenskaug at the Center for Industriforskning in Oslo, Norway has been developing an object-oriented design method that focuses on roles, synthesis, and structuring. The method, called Object-Oriented Role Analysis, Syntheses and Structuring, is based on first modeling small sub-problems, and then combining small models into larger ones in a controlled manner using both inheritance (synthesis) and run-time binding (structuring).We then present investigations by Ralph Johnson at the University of Illinois at Urbana-Champaign into object-oriented frameworks and the reuse of large-scale designs. A framework is a high-level design or application architecture and consists of a suite of classes that are specifically designed to be refined and used as a group. Past work has focused on describing frameworks and how they are developed. Current work includes the design of tools to make it easier to design frameworks.Finally, we present some results from the research group in object-oriented software engineering at Northeastern University, led by Karl Lieberherr. They have been working on object-oriented Computer Assisted Software Engineering (CASE) technology, called the Demeterm system, which generates language-specific class definitions from language-independent class dictionaries. The Demeter system include tools for checking design rules and for implementing a design.
Surface-Enhanced Resonance Raman Scattering and Visible Extinction Spectroscopy of Copper Chlorophyllin: An Upper Level Chemistry Experiment.

Advanced chemistry students are introduced to surface-enhanced resonance Raman scattering (SERRS) by studying how sodium copper chlorophyllin (CuChl) adsorbs onto silver colloids (CuChl/Ag) as a function of pH. Using both SERRS and visible extinction spectroscopy, the extent of CuChl adsorption and colloidal aggregation are monitored. Initially at pH ∼10, the colloids possess an overall negative surface charge, preventing attraction. Surface-enhanced Raman scattering (SERS) is not detected at that pH because the relatively small colloids do not possess a surface plasmon in resonance with the laser excitation frequency (633 nm). Once the solution pH decreases slightly, colloidal clusters form and SERRS is detected. As the pH is lowered to a value of 4 or 3, protonation of CuChl results in colloidal aggregation and precipitation. If adsorption and aggregation are halted by adding H2SO4(aq) and then NaOH(aq), an intense SERRS signal is steadily detected from acidic pH (about 4), back to the initial basic pH (about 10).
Suitability of Some Fresh Water and Marine Fishes for Use with a Minicomputer Interfaced Biological Monitoring System

ABSTRACT: Electronic modifications necessary to adapt an existing fish opercular movement monitor for use in salt water are described. Ten species of fresh and salt water fishes were tested for suitability as test organisms for future studies of pollutional effects. It was concluded that with proper tank design most species would provide useful data and that the system could be easily adapted for use in marine situations.
Evidentiary mechanisms and routine expansion

Etude du mecanisme evidentiaire (evidentiary) developpe par S. Hallden et M. Edman qui consiste a evaluer un systeme operationel, place dans une situation donnee, en fonction de la reponse e' qu'il apporte a l'hypothese h' et de l'importance du programme d'expansion routiniere qui lui est imparti
A study of glycolytic control mechanisms in giant tissue culture ascites cells by microfluorimetry-microelectrophoresis

1. In the study of glycolytic control mechanisms, the meaning of enzymic assays is extrapolated to the living cell. The results of such extrapolation are now amenable to direct verification in the living cell using the microfluorimetry-microelectrophoresis technique. The microfluorimetric study of the blue fluorescence responses in the extramitochondrial compartment of giant tissue culture ascites cells (EL2 giants) provides a quantitative evaluation of the glycolytic pyridine nucleotide reduction. 2. The response to microelectrophoretically introduced metabolites is dependent upon the steady state level of the extra-mitochondrial pyridine nucleotide reduction in the EL2 giant, and the metabolic state prior to treatment. The difference in responses between non-inhibited starved glucose-free and inhibited glucose-fed cells can be exploited for the study of glycolytic control mechanisms. 3. A striking point is the inadequacy of single intermediates such as G6P, ADP, cyclic AMP or Pi alone to relieve the metabolic block. More effective relief of metabolic inhibition is observed with multicomponent microelectrophoretic mixtures. 4. The microelectrophoretic mixtures most effective in relieving the metabolic block are FDP + ADP + Pi, G6P + FDP + ADP + Pi and G6P + FDP + ATP + ADP + Pi. 5. The results obtained suggest a multisite-multicomponent control of glycolysis in EL2 giants and indicate also the role of mitochondrialcytoplasmic interactions.
Draney Limestone--Early Cretaceous Lacustrine Carbonate Deposition in Western Wyoming and Southeastern Idaho: ABSTRACT

The Lower Cretaceous Draney Limestone, a lenticular carbonate sequence well exposed throughout the Overthrust belt in western Wyoming and southeastern Idaho, records deposition in an extensive, shallow, low-salinity lacustrine system that minimally covered 30,000 sq km. The predominant lithologies of calcareous mudstone, micrite, intramicrite, and biomicrite contain a lacustrine biota composed predominantly of ostracods and the calcareous alga Chara, with less common bivalves and gastropods. The continuity of the Draney throughout the area indicates that this lake was a more or less continuous body of water throughout deposition. Individual units within the Draney, however, cannot be correlated over large distances; this fact suggests significant local chemical and/or phy ical variations within the lake basin during carbonate deposition. The lake appears to have been relatively shallow throughout its extent, as evidenced by the presence of winnowed sandy biomicrite and the ubiquitous Chara, which in modern systems is restricted to shallow photic zones. Limonitic calcareous mudstones which exhibit well-developed calcite boxwork fabrics and vugs filled with calcite spar indicate infrequent subaerial exposure and alteration of lake sediments. Modern playa systems do not serve as a satisfactory analog to the Draney lake because features indicative of (1) frequent subaerial exposure, (2) deposition in exceedingly shallow water, or (3) coprecipitation of more evaporitic minerals have not been observed in the Cretaceous sections. On the contrary, lithologic, faunal, and floral features of Draney strata are more nearly identi al to those of marl deposits in modern, temperate-region, hardwater lakes. Therefore, Cretaceous carbonate deposition under somewhat similar conditions is suggested. End_of_Article - Last_Page 425------------
In Vitro Remineralization Effects of Grape Seed Extract on Artificial Root Caries

Grape seed extract (GSE) contains proanthocyanidins (PA), which has been reported to strengthen collagen-based tissues by increasing collagen cross-links. We used an in vitro pH-cycling model to evaluate the effect of GSE on the remineralization of artificial root caries. Sound human teeth fragments obtained from the cervical portion of the root were stored in a demineralization solution for 96 h at 37 degrees C to induce artificial root caries lesions. The fragments were then divided into three treatment groups including: 6.5% GSE, 1,000 ppm fluoride (NaF), and a control (no treatment). The demineralized samples were pH-cycled through treatment solutions, acidic buffer and neutral buffer for 8 days at 6 cycles per day. The samples were subsequently evaluated using a microhardness tester, polarized light microscopy (PLM) and confocal laser scanning microscopy (CLSM). Data were analyzed using ANOVA and Fisher's tests (p 0.05), which was confirmed by CLSM. We concluded that grape seed extract positively affects the demineralization and/or remineralization processes of artificial root caries lesions, most likely through a different mechanism than that of fluoride. Grape seed extract may be a promising natural agent for non-invasive root caries therapy.
THE APPLICATION OF LATZKO'S QUALITY MEASURING SYSTEM TO THE IMPROVEMENT OF A COMPUTER MESSENGER SERVICE

The Quality Measuring System (QMS) methodology of William J. Latzko was employed to improve the quality of the computer messenger service in Sandia Laboratories' computing organization. The technique requires a high level of cooperation and participatio..
Test to distinguish a Brownian motion from a Brownian bridge using Polya tree process

Abstract The problem of distinguishing a Brownian bridge from a Brownian motion, both with possible drift, on the closed unit interval, is investigated via a pair of hypothesis tests. The first, tests for observations obtained at n discrete time points to be arising from a Brownian bridge with drift by embedding the Brownian bridge into a mixture of Polya trees which represents the non-parametric alternative. The second test, tests in an identical manner, for the observations to be coming from a Brownian motion with drift. The Bayes factors for the two tests are derived and then combined to obtain the Bayes factor for the test to distinguish between the two Gaussian processes. The Tierney–Kadane approximation of the Bayes factor is derived with an error approximation of order O ( n − 4 ) .
Magnetic phase boundaries near the bicritical and Néel points of Cr 2 O 3

The magnetic phase diagram of the easy-axis uniaxial antiferromagnet ${\mathrm{Cr}}_{2}$${\mathrm{O}}_{3}$ was measured in magnetic fields $\stackrel{\ensuremath{\rightarrow}}{\mathrm{H}}$ up to 180 kOe. Phase transitions were determined from anomalies in the attenuation of 30- and 50-MHz longitudinal ultrasonic waves. Temperatures $T$ were measured with a precision of \ensuremath{\sim}10 mK, corresponding to $\frac{\ensuremath{\Delta}T}{T}\ensuremath{\sim}3\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}5}$. Attention was focused on the phase boundaries near both the N\'eel point (${T}_{N}=307.3$ K) and the bicritical point [${T}_{b}={T}_{N}\ensuremath{-}(0.505\ifmmode\pm\else\textpm\fi{}0.01)$ K, ${H}_{b}=120.04\ifmmode\pm\else\textpm\fi{}0.6$ kOe]. Data were taken for $\stackrel{\ensuremath{\rightarrow}}{\mathrm{H}}$ parallel to the easy axis, perpendicular to the easy axis, and for some intermediate orientations. Near the bicritical point, the phase boundaries in the $T\ensuremath{-}{H}_{\ensuremath{\parallel}}\ensuremath{-}{H}_{\ensuremath{\perp}}$ space (where $\ensuremath{\parallel}$ and $\ensuremath{\perp}$ indicate parallel and perpendicular to the easy axis, respectively) show marked deviations from mean-field theory. In contrast, the recent theory of Fisher, Nelson, and Kosterlitz (FNK) explains all the salient features of the phase boundries near the bicritical point. The crossover exponent $\ensuremath{\varphi}$ was determined from numerical fits of the data near the bicritical point taken (i) with $\stackrel{\ensuremath{\rightarrow}}{\mathrm{H}}$ parallel to the easy axis, and (ii) with $\stackrel{\ensuremath{\rightarrow}}{\mathrm{H}}$ gradually tipped away from the easy axis, keeping ${H}_{\ensuremath{\parallel}}={H}_{b}=\mathrm{const}$. The values for $\ensuremath{\varphi}$ were consistent with the FNK theory. However, it appears that Fisher's estimate for one of the "best" scaling axes ($\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{t}=0$, for $\stackrel{\ensuremath{\rightarrow}}{\mathrm{H}}$ parallel to the easy axis) is not applicable to ${\mathrm{Cr}}_{2}$${\mathrm{O}}_{3}$. Near ${T}_{N}$ and with $\stackrel{\ensuremath{\rightarrow}}{\mathrm{H}}$ parallel to the easy axis, the ordering temperature ${T}_{c}$ decreases linearly with ${H}^{2}$. However, for $\stackrel{\ensuremath{\rightarrow}}{\mathrm{H}}$ perpendicular to the easy axis, ${T}_{c}$ increases with increasing $H$ in fields up to 180 kOe. This increase is attributed to the extremely low anisotropy of ${\mathrm{Cr}}_{2}$${\mathrm{O}}_{3}$ which causes the behavior in perpendicular fields to qualitatively resemble the behavior predicted by FNK for the completely isotropic antiferromagnet. Ultrasonic methods for determining phase boundaries of antiferromagnets are reviewed briefly.
Effects of Insecticide Resistance on Biotic Potential of the House Fly (Diptera: Muscidae)

Biotic potential (length of developmental period and fecundity) was measured for one susceptible (S) and four organophosphate insecticide-resistant (R) strains of Musca domestica L. and for RS heterozygotes. The R strains showed an 11 to 43% decrease in biotic potential relative to the S strain. The decrease was associated with reduced fecundity in all R strains and an increase in developmental time in two of them. In contrast, the biotic potential of RS heterozygotes, which are resistant, was seldom different from the S strain. Therefore, the R gene is dominant for expression of resistance but recessive for adverse effects on biotic potential. This may result in the occurrence of a balanced polymorphism in field situations. The implications of these findings for resistance managment are discussed.
Functional mapping of quantitative trait loci that interact with the hg mutation to regulate growth trajectories in mice.

The high growth (hg) mutation increases body size in mice by 30–50%. Given the complexity of the genetic regulation of animal growth, it is likely that the effect of this major locus is mediated by other quantitative trait loci (QTL) with smaller effects within a web of gene interactions. In this article, we extend our functional mapping model to characterize modifier QTL that interact with the hg locus during ontogenetic growth. Our model is derived within the maximum-likelihood context, incorporated by mathematical aspects of growth laws and implemented with the EM algorithm. In an F2 population founded by a congenic high growth (HG) line and non-HG line, a highly additive effect due to the hg gene was detected on growth trajectories. Three QTL located on chromosomes 2 and X were identified to trigger significant additive and/or dominant effects on the process of growth. The most significant finding made from our model is that these QTL interact with the hg locus to affect the shapes of the growth process. Our model provides a powerful means for understanding the genetic architecture and regulation of growth rate and body size in mammals.
Synthesis and characterization of new ferrocenylamine sulfide ligands and their palladium complexes as catalysts for selective hydrogenation

Abstract A series of new achiral and chiral ferrocenylamine sulfides and their palladium complexes of type (C5H5)Fe[(C5H3)(CH2NR2)(SR′)]PdCl2 (R=Et; R′=Me, Et, 4-chlorophenyl, p-tolyl; R=n-Pr, R′=Me, Et), (S,R)-(C5H5)Fe[(C5H3)(CHMeNR2)(SR′)]PdCl2 (R=Et, n-Pr; R′=Me) and (R,S)-(C5H5)Fe[(C5H3)(CHMeNR2)(SR ) ]PdCl2 (R=Et, n-Pr; R′=Et, i-Pr) were synthesized. Their applications as homogeneous catalysts in hydrogenation of 1,3-cyclo-octadiene have been examined. These new catalysts showed superior activity and selectivity over other palladium ferrocenylamine sulfide complexes. Their catalytic activities were dependent on the steric bulkiness of both the amine and sulfide substituents. The effects of pressure on the reaction rates and selectivities were also investigated.
Assessment of controller situation awareness in future terminal RNAV operations

The MITRE Corporation's Center for Advanced Aviation Systems Development (CAASD) was tasked by the Federal Aviation Administration (FAA) with defining and validating the performance-based air traffic management (ATM) concept to address the increasing need for improved capacity, efficiency, and productivity in the National Airspace System (NAS). A key enabler of this concept is the continued implementation and greater utilization of performance-based navigation provided by area navigation (RNAV) and required navigation performance (RNP) today and through the future. Implementation of new procedures and features, such as vertical profiles, are expected to reduce the active controlling task that is fundamental to air traffic control (ATC) operations and instead, increase monitoring of operations. This change is intended to leverage flight deck automation and reduce pilot and controller workload; however, it is critical to fully understand the human factors implications of making this shift, especially as traffic operations continue to grow. A human-in-the-loop (HITL) simulation was performed to evaluate changes in situation awareness for the feeder arrival controller position in a terminal radar approach control (TRACON) environment with conventional arrival operations and with future RNAV arrival operations when moderate and high levels of traffic were managed. An assessment of controller situation awareness was made based upon results from the situation awareness global assessment technique (SAGAT) and measurement of controller detection of pre-planned aircraft deviations from their assigned clearance. Workload was also measured using the NASA-task load index (TLX). Findings suggest that a change of controller situation awareness does occur as a result of the increased traffic levels managed. Assessing and mitigating this issue is under study by MITRE/CAASD, in particular through display and alerting automation for radar controllers.
Blackmail: A Preliminary Inquiry

Most of us are inclined to believe that blackmail is clearly immoral (even a particularly sleazy kind of immorality) and are thus quite content that it be criminalized.2 Justifying this belief, however, turns out to be more of a problem than it might at first seem. In particular, it is difficult if not impossible to distinguish cases of blackmail (which we prohibit) from other hard economic transactions (which, even if we do not totally approve of them, we do not criminalize).
Electronic Mapping in Education: The Use of Geographic Information Systems

AbstractElectronic mapping can serve as a powerful educational tool in the instruction of classroom students and in the administration of campuses and school districts. Electronic mapping’s availability in the educational setting is because of the accessibility of geographic information systems (GIS) that provide mapping and cartography functions in a cost-effective manner. The appropriate integration of GIS can strengthen the teaching of essential elements in geography and social studies as well as address school administration issues (e.g., facilities planning, bus routes).
Accentuated vagal antagonism of beta-adrenergic effects on ventricular repolarization. Evidence of weaker antagonism in hostile type A men.

BACKGROUND Prior research has suggested a weaker parasympathetic antagonism of sympathetic effects on the heart in type A (coronary-prone) men. To confirm this phenomenon and extend our understanding of it, we investigated the effects of prior muscarinic blockade on the electrocardiogram T wave and other cardiovascular and neuroendocrine responses to isoproterenol in type A and type B (non-coronary-prone) men. METHODS AND RESULTS Responses to two 5-minute intravenous isoproterenol infusions (0.01 micrograms/kg/min and 0.02 micrograms/kg/min) were evaluated in six type A and six type B men after pretreatment with either dextrose placebo or atropine (1.2 mg). Atropine significantly potentiated T wave attenuation in the recovery period after isoproterenol infusion (0.30 +/- 0.07 mV) compared with placebo (0.54 +/- 0.09 mV, p less than 0.001). Atropine also potentiated the heart rate increase to isoproterenol (39 +/- 3 beats per minute versus 20 +/- 2 beats per minute after placebo). Atropine enhanced decreases in systolic, diastolic, and mean arterial pressures as well as pulse pressure to isoproterenol. Atropine enhancement of many of these responses was increased among subjects with high scores on various hostility/anger scales. Isoproterenol alone produced greater T wave attenuation in type A than in type B men. However, atropine enhancement of T wave attenuation and blood pressure falls by isoproterenol was present only in type B men. CONCLUSIONS These findings indicate that there is accentuated parasympathetic antagonism of T wave attenuation and blood pressure responses induced by beta-adrenergic stimulation. Relative weakness of this antagonism of sympathetic effects on the heart in hostile type A individuals may contribute to their higher coronary disease risk.
Gender Differences in the Politicization of American Children

Resaerch on preadult political socialization conducted prior to the women's movement and the rise of feminist consciousness indicated that girls lagged behind boys in many aspects of their political development. Studies in the 1970s showed that this gap was closing. We examine preadult political orientations in the 1980s, and discover that the optimism of prior research is perhaps premature. Significant gender-related differenes exist for girls and boys, as well as for their parents, on a variety of measures of "politicization." Evidence suggests that these distinctions are passed on through the socialization process in the family at least to some degree. Structural and cultural factors may further contribute to the persistence of gender-based distinctions in politicization.
Photooxidative effects on properties and structure of high‐density polyethylene

The environmental degradation of high-density polyethylene (HDPE) has been studied, in addition to that of HDPE blends, containing various concentrations of ethylene carbon monoxide copolymer. Extruded sheets of each material were exposed to natural Arizona sunlight for times up to 6 months. Exposed samples were then analyzed with respect to molecular weight, density, thermal behavior, mechanical properties, and infrared absorption. Additional samples were exposed to laboratory weathering conditions, evaluated in terms of property changes, melted, reformed, and then reevaluated without further weathering exposure. Results indicate that sunlight exposure causes decreased elongation to break, increased embrittlement, decreased molecular weight, and increased crystallinity. Environmental oxidative degradation is elucidated by the measurement of specific infrared bands, sensitive to the formation of carbonyl and vinyl end groups. As environmental degradation causes reductions of molecular weight, polymer chain mobility increases, leading to a higher degree of crystallinity. This increased crystallinity, along with the decreased molecular weight, accounts for the loss of ductility, indicated by a sharp decrease in ultimate elongation. The presence of carbon monoxide copolymer in the blended samples accelerates the process of environmental degradation, however, the degradation mechanisms appear to be similar to those observed for nonblended HDPE. © 1994 John Wiley & Sons, Inc.
An RLC interconnect model based on fourier analysis

Based on a Fourier series analysis, an analytic interconnect model is presented which is suitable for periodic signals, such as a clock signal. In this model, the far-end time-domain waveform is approximated by the summation of several sinusoids. Closed-form solutions of the 50% delay and overshoots/undershoots are provided when the fifth and higher order harmonics are ignored. Good accuracy is observed between the model and SPICE simulations. The model is applied to resistance-capacitance-inductance interconnect trees and the computational complexity of the model is linear with the size of the tree and the model order. The tree model is shown to be an effective method to analyze clock distribution networks. The single interconnect model is also extended to coupled multi-interconnect systems to analyze crosstalk noise and a general waveform solution is obtained. It is noted that in addition to the transition time, the period of the aggressor signal also has a significant effect on the crosstalk noise.
The binding of salicylic acid and acetylsalicylic acid to human serum albumin

1. The binding of salicylic acid (SA) and acetylsalicylic acid (ASA) to human serum albumin (HSA) has been further elucidated through use of the gel filtration technique of Hummel. The method is analogous in principle to equilibrium dialysis and is suited to study the binding of small molecules to macromolecules. The bound complex is placed on a column previously saturated with a solution of the small molecule and is eluted with the same concentration of small molecule. 2. Results using this method show the HSA-ASA bond to be strong in comparison to the relatively weak binding of SA to HSA. Evidence points to the conclusion that the HSA molecule has a relatively large number of weak binding sites for SA in comparison to a smaller number of stronger binding sites for ASA. Time studies indicated that ASA equilibrium binding was reached only after 120–150 hours of contact with HSA.
Seed bank dynamics of Lythrum salicaria L.: implications for control of this species in North America

Abstract The seed bank of Lythrum salicaria L. was studied in wetlands of mid-continent North America where this Eurasian species is considered a nuisance. Recruitment under conditions chosen to promote high rates of germination did not exhaust the seed bank in a 1-cm deep layer of wetland soil in experimental flats. Emergence of seedlings from experimentally buried seed decreased linearly ( P = 0.0001, R 2 = 0.89) from 90% at the soil surface to 0% at 2 cm. In the wetlands studied, there were 410 000 L. salicaria seeds m −2 in the top 5 cm of soil; 37% of these were found below a depth of 2 cm. The implications of these results for the control of this species are discussed.
Epidermal differentiation governs engineered skin biomechanics

Engineered skin must be mechanically strong to facilitate surgical application and prevent damage during the early stages of engraftment. However, the evolution of structural properties during culture, the relative contributions of the epidermis and dermis, and any correlation with tissue morphogenesis are not well known. These aspects are investigated by assessing the mechanical properties of engineered skin (ES) and engineered dermis (ED) during a 21-day culture period, including correlations with cellular metabolism, cellular organization and epidermal differentiation. During culture, the epidermis differentiates and begins to cornify, as evidenced by immunostaining and surface electrical capacitance. Tensile testing reveals that the ultimate tensile strength and linear stiffness increase linearly with time for ES, but are relatively unchanged for ED. ES strength correlates significantly with epidermal differentiation (p < 0.001) and a composite strength model indicates that strength is largely determined by the epidermis. These data suggest that strategies to improve ES biomechanics should target the dermis. Additionally, time-dependant changes in average ES strength and percent elongation can be used to set upper bound limits on mechanical stimulation profiles to avoid tissue damage.
Usefulness of specific IgE antibody tests: a progress report

Learning Objectives To enable the readers to recognize some of the history, problems, progress, interpretation, and present status of assays for specific IgE (s-IgE) antibodies. Data Sources Peer-reviewed literature in the field. Study Selection Key articles were selected by the author. Results Clinical and analytical studies have differed widely in their conclusions as to the performance of tests for s-IgE. Study conclusions depend on the testing method used, the allergen(s) studied, patient selection, and, most importantly, the standards used for comparison. Today, only a handful of the once commercially developed assays still exist, and some of these still do not compare well to an analytical ideal standard. However, with the extent of regulation and economic pressures, most of the surviving s-IgE tests are considerably improved over what had existed before them. Conclusions Allergic diseases with multiple symptom patterns seem to be increasing in modern societies. Objective methods are needed to differentiate allergic origins from other mechanisms that cause similar symptoms. Accurate, quantitative, and objective methods for s-IgE measurement are now available and can be used effectively in clarifying allergic diagnoses when interpreted in conjunction with the clinical history.
Antioxidants, mitochondrial hyperoxidation and electrical recovery after anoxia in hippocampal slices

Cerebral injury may occur not only during brain ischemia but also during reperfusion afterward. A characteristic event during reperfusion after cerebral ischemia, or reoxygenation after anoxia in hippocampal slices, is hyperoxidation of the electron carriers of the mitochondrial respiratory chain. Earlier studies suggested that mitochondrial hyperoxidation was produced by an oxyradical mechanism and was linked to neuronal damage. Present studies sought to test this hypothesis by determining whether antioxidants could suppress mitochondrial hyperoxidation and improve electrical recovery after anoxia in hippocampal slices. Both 500 microM ascorbate and 50 microM glutathione decreased post-anoxic hyperoxidation of NADH and improved electrical recovery in hippocampal slices. These data support a role of oxygen free radicals in promoting post-anoxic mitochondrial hyperoxidation and electrical failure, and suggest that these effects of anoxia or ischemia may be linked.
Increased susceptibility of Cryptococcus neoformans to amphotericin B in the presence of steroids.

The in vitro inhibitory effects of amphotericin B in the presence of estradiol, norethynodrel, testosterone, progesterone and diethylstilbestrol on 7 human isolates of C. neoformans was determined. At 4 days of incubation at 25°C the growth of all isolates was completely suppressed by 0·5 μg/ml of diethyl-stilbestrol plus 0·3 μg/ of amphotericin B, while either compound by itself did not suppress growth. At 4 days, 0·01 μg of estradiol plus 0·3 μg/ml of amphotericin B completely suppressed the growth of 5 isolates, while either compound failed to suppress growth completely. The minimal inhibitory concentration of estradiol, diethylstilbestrol, in combination with amphotericin B is much lower than with the steroids alone or amphotericin B alone. Amphotericin B with diethylstilbestrol might be more effective in the treatment of cryptococcal meningitis than amphotericin B. alone.
The effect of power and gender on technology acceptance

Purpose – This paper aims to examine the joint effect of power and gender on individuals’ perceptions and evaluations of information systems (IS), and their behavioral intentions of technology acceptance. Design/methodology/approach – This study uses a 2 (powerful vs powerless) × 2 (female vs male) between-subject experimental design. A total of 128 subjects participated in the experiment. Findings – The results suggest that there is a significant gender difference in terms of technology acceptance in the high-power condition. Further, such a gender difference is attenuated in the low-power condition. Specifically, when primed with the feeling of powerful, male users (vs female users) have higher computer self-efficacy and rate the IS as easier to use and more enjoyable. However, when the feeling of powerless was elicited, the effect of gender on technology acceptance disappeared. Originality/value – The gender effect on technology acceptance has been widely studied. The current research extends the liter...
Issues in software cycle time reduction

During the early days of commercial software development, cost and performance were the factors that received the most attention as an area for improvement. In the 1980's quality and productivity have received a great deal of attention. It appears that, in the 1990's reducing software development time will be one of the primary goals of large and small software companies alike. To this end it is appropriate to examine the factors that affect software cycle time. Is it enough to try and improve programmer productivity or are there additional product or process improvements that might be considered? Assuming there are several factors that impact software development time, what are they and how much of an impact does each factor have? This paper examines the software development cycle. It motivates the importance of software cycle time reduction. A definition for software cycle time is proposed. The potential trade-offs of a focus on cycle time reduction are examined. Using a systematic approach, a comprehensive set of cycle time factors is identified and categorized. Using this set of factors this paper reviews and evaluates existing cycle time reduction approaches. Finally, an argument is made for a product centered cycle time approach. This paper establishes a common ground from which future research in this area may continue. >
A new networking model for biological applications of ad hoc sensor networks

In this paper, we introduce the Shared Wireless Infostation Model (SWIM), which extends the Infostation model by incorporating information replication, storage, and diffusion into a mobile ad hoc network architecture with intermittent connectivity. SWIM is able to reduce the delay of packet delivery at the expense of increased storage at the network nodes. Furthermore, SWIM improves the overall capacity-delay tradeoff by only moderately increasing the storage requirements. This tradeoff is examined here in the context of a practical application-acquisition of telemetry data from radio-tagged whales. To reduce the storage requirements, without affecting the network delay, we propose and study a number of schemes for deletion of obsolete information from the network nodes. In particular, through the use of Markov chains, we compare the performance of five such storage deletion schemes, which, by increasing the computational complexity of the routing algorithm, mitigate the storage requirements. The results of our study will allow a network designer to implement such a system and to tune its performance in a delay-tolerant environment with intermittent connectivity, as to ensure with some chosen level of confidence that the information is successfully carried through the mobile network and delivered within some time period.
Recruitment of Circulating Breast Cancer Cells Is Stimulated by Radiotherapy

SUMMARY Radiotherapy (RT) is a localized therapy that is highly effective in killing primary tumor cells located within the field of the radiation beam. We present evidence that irradiation of breast tumors can attract migrating breast cancer cells. Granulocyte-macrophage colony stimulating factor (GM-CSF) produced by tumor cells in response to radiation stimulates the recruitment of migrating tumor cells to irradiated tumors, suggesting a mechanism of tumor recurrence after radiation facilitated by transit of unirradiated, viable circulating tumor cells to irradiated tumors. Data supporting this hypothesis are presented through in vitro invasionassaysand invivo orthotopic models of breast cancer. Our work provides a mechanism for tumor recurrence in which RT attracts cells outside the radiation field to migrate to the site of treatment.
L2 Writing Conferences: Investigating Teacher Talk.

Abstract Although the role of social interaction through conversational activities is well established in the L2 writing classroom in relation to idea development, understanding rhetorical modes, the creation of a sense of audience, as well as the promotion of feedback, relatively little attention has been given to the actual discourse of teachers and learners, particularly in face-to-face writing conferences. Previous investigations of teacher talk in L2 conferences suggest that when there is more talk around revision in the conference, the revisions are more successful. However, these studies have employed different frameworks for analysis, investigated mostly high-proficiency learners, and have not systematically compared the relationship of the topics addressed in the conferences to the nature of the discourse. In contrast, this study employs two frameworks for analysis, negotiation and scaffolding, to investigate the discursive quality of two teachers, whose writing conferences with prematriculated ESL learners attended to very different writing concerns. Neither framework alone captured the differences between the teachers’ conferences, but together patterns of difference were evident. Certain combinations of negotiation and scaffolding moves in relation to conference focus allowed one teacher to vary assistance in relation to the proficiency of the learners and promote greater learner participation in the review of their writing.
Enhanced phase noise modeling of fractional-N frequency synthesizers

Mathematical models for the behavior of fractional-N phase-locked-loop frequency synthesizers (Frac-N) are presented. The models are intended for calculating rms phase error and determining spurs in the output of Frac-N. The models describe noise contributions due to the charge pump (CP), the phase frequency detector (PFD), the loop filter, the voltage control oscillator, and the delta-sigma modulator. Models are presented for the effects of static CP gain mismatch, CP dynamic mismatch and PFD reset delay mismatch. A simple analytic expression shows the level of /spl Delta//spl Sigma/ sequence noise caused by static CP current mismatch. We further show that un-equal rise time and fall time constants of the CP result in dynamic mismatch noise. Reset delay mismatch in PFD is shown to also contribute significantly to close-in phase noise. The model takes into account the reduction in CP thermal and flicker noise due to the changing duty cycle of Frac-N CP. Our model is therefore useful in characterizing the noise performance of Frac-N at the system-level, simplifying the design of fractional-N synthesizers and transmitters. Analytical and simulated results are compared and show good agreement with prior published data on Frac-N realizations.
The Perils of Adding Up: A Cautionary Tale about Modeling and Regression Analysis

To turn incomplete or imperfectly reliable information into estimates useful for policy, some modeling is often necessary or helpful. It does not follow that every statistical relation constitutes a model. There has to be an underlying theory, and the numerical estimates must respect any definitional or accounting identities that constrain the results. Ad hoc relations that do not meet these criteria can lead to uninterpretable or meaningless values, especially when different partial values, separately estimated, are added together. The imputed values of "responsiveness" in the WHO World Health Report 2000 illustrate this danger.
Scheduling multi-component applications in heterogeneous wide-area networks

We present a scalable scheduling heuristic for several common classes of multi-component applications (meta-applications). We consider this scheduling problem in a wide-area heterogeneous computing environment, or metasystem. The heterogeneity and scale of the computing environment and the heterogeneity of the application make this a challenging problem. We have studied the performance of the heuristic in simulation and the results are encouraging. Completion times for three common classes of meta-applications were within 10-20% of optimal on average with a worst-case variance of 60%. The results suggest that effective scheduling of meta-applications is possible, if sufficient application and system resource cost information is provided.
Thalamic axons confer a blueprint of the sensory periphery onto the developing rat somatosensory cortex.

Abstract In order to study the role of afferents in the maturation of cortical patterns, axons projecting from the ventrobasal thalamic complex (VB) to the barrel field (SI) cortex were labeled with the carbocyanine dye Dil, in aldehyde-fixed embryonic and newborn rat brains. Our results reveal that the first few thalamic axons are in the cortical plate by embryonic day (E) 19. Between E19 and the day of birth (E21 = PND 0), layers V and VI differentiate from the lower part of the cortical plate. On PND 0, a plexus of growth-cone tipped thalamic axons is present within the cortical plate and a few VB fibers have reached the marginal zone. Increasing numbers of thalamic afferents invade and ramify within the cortical plate on PND 1 and, over the course of the next 24 h, form a vibrissa-specific pattern in the lower part of this zone, prior to the differentiation of layer IV into a distinct lamina. This periphery-related organization is exhibited by VB afferents earlier than reported for other afferents to the cortex, by glia- or neuron-associated extracellular elements or by the cytoarchitectonic specializations (barrels) of stellate cells. Our observations, in conjunction with the previous studies, demonstrate that thalamic afferents may have a pivotal role in determining the morphological specification of the primary somatosensory cortex.