cssi/SciSciGPT-SciSciNet huggingface dataset:
Observation of elliptical rings in type-I spontaneous parametric downconversion

We investigate the transverse spatial profile of downconverted light produced by noncollinear, degenerate, type-I spontaneous parametric downconversion in two types of nonlinear crystals. We find that the pattern produced by one crystal, beta barium borate (BBO), produces a circular downconversion pattern while the other crystal, bismuth triborate (BiBO), produces an elliptical pattern. We show this difference is due to the angle-independent refractive index experienced by the daughter photons in BBO, while they experience an angle-dependent refractive index in BiBO. We image the transverse spatial profile of the generated light to determine the eccentricity produced by each crystal and develop a model to explain our observation. Among other things, this model predicts that there is a wavelength for which the eccentricity from BiBO is nearly zero. Finally, we discuss how the elliptical ring pattern produced in BiBO potentially affects polarization entanglement for experimental setups that collect biphotons around the entire downconversion ring. We show that the quality of polarization entanglement as measured by the overlap integral of the spectrum of the two rings can remain high (>99.4%) around the entire ring at the expense of decreased biphoton rate.
An annual survey ofHermesium adriaticum andEbria tripartita, two ebridian algae in the lower Chesapeake Bay

Two colorless flagellates,Hermesinum adriaticum andEbria tripartita, were found in the upper meter of water in Mobjack Bay and the York River.Hermesinum was abundant in the summer months when water temperatures were maximum for the area.Ebria was abundant at this and other times of the year. There was no correlation of temperature and abundance for the latter flagellate.
Formalism for determining pseudostates in modified close-coupling calculations

A formalism for determining pseudostate wave functions for use in modified close-coupling calculations is presented. Applications to low-energy electron-hydrogen scattering are discussed. The 2p-bar pseudostate proposed by Damburg and Karule is analyzed using this formalism and a reason for its success is given which is independent of the fact that it fully accounts for the ground-state polarizability of atomic hydrogen. The analysis suggests, in agreement with expectations of Burke and Schey and others, that short-range correlations are more important than long-range polarization in determining the best form of the pseudostates.
Technological and Organizational Adaptation of EMR Implementation in an Emergency Department

Implementation of large Health Information Technology (HIT) systems is critical to healthcare organizations and has seen heavy investment. However, research has not fully explored the adaptation of HIT systems, particularly the tensions between individual flexibility and organizational needs in the adaptation process. This study analyzes how Emergency Department (ED) clinicians adapted to a new hospital-wide Electronic Medical Records (EMR) system. We present four adaptation cases revealing two interrelated types of adaptations—technical and organizational—as responses to the new system in use. First, individual clinicians respond to the immediate alteration in workflows caused by the EMR, while the organizational adaptations later mitigate the changes in healthcare quality control resulting from the clinicians’ initial adaptation. Our analysis reflects the critical nature and value of both adaptation types, with an emphasis on the triggers and process of organizational adaptation, for the successful implementation of a socio-technical-political system in a healthcare organization.
Consumer acceptance of food irradiation: a test of the recreancy theorem

Consumers living in both developed and developing nations rely upon foods that have been produced and processed in many countries and in a wide variety of ways. Therefore, it is not surprising that they express concerns about the safety of their food supplies. A technology proposed to improve consumer trust in food safety is irradiation. Despite extensive education efforts and endorsements given by many health-related organizations worldwide, food irradiation has been slow to gain widespread acceptance. This ineffectiveness of diffusion efforts might indicate a need to broaden our theoretical perspectives of consumer acceptance of controversial technologies. Most theoretical approaches explain acceptance primarily as a function of perceived risks associated with a technology. The recreancy theorem, in contrast, explains acceptance as a function of public trust in societal institutions to effectively manage a technology. This study investigated the extent to which the recreancy theorem explained acceptance of food irradiation by US consumers, while statistically controlling for perceived risk and social-demographic variables. The study used a longitudinal field design to survey one adult each in 116 households located in the Minneapolis, Minnesota area during the first large-scale market test of irradiated food. The results indicate that the recreancy theorem might provide a valid conceptual approach to gaining a broader understanding of consumer acceptance of controversial new technologies.
Prediction of wetting front stability in dry field soils using soil and precipitation data

Abstract A need exists for information regarding the stability of wetting fronts in field soils because they increase the vulnerability for groundwater contamination. In this study, we develop a simple approach for the evaluation of wetting front stability in dry soils. We show that the stability of wetting fronts in the top layer of a soil depends both on the type of soil and the intensity of the precipitation. Our approach distinguishes stability criteria for wetting events that are different for a high, intermediate, and low infiltration rate. At high infiltration rates , wetting fronts are stable if the infiltration rate exceeds or equals the saturated hydraulic conductivity of the soil. The stability criterion for low infiltration rates (less than approximately 0.2 cm/h for sand soils) is based on two characteristics times[ a gravitational time and an infiltration time. The gravitational time, t grav , indicates when gravity and capillarity each contribute equally to the process of infiltration. The infiltration time, t infil , is the duration of the infiltration event. Experimental and literature data show that in well-sorted laboratory sands, wetting fronts are stable when t infil grav . This expression can also be expressed as Wi 2 with W the total amount of precipitation, i its intensity, and S the sorptivity at a slightly positive soil-water pressure. For intermediate infiltration rates , wetting fronts remain stable as long as W is smaller than the amount of water needed to wet a distribution layer near the surface. The application of the stability criteria is demonstrated with a case study from the Sevilleta dunes near Socorro, NM.
EFFECTS OF SURFACTANT ADSORPTION—DESORPTION KINETICS AND INTERFACIALRHEOLOGICAL PROPERTIES ON THE RATE OFDRAINAGE OF FOAM AND EMULSION FILMS

An analysis has been developed to describe the rate of drainage of an axi-symmetric plane-parallel foam and emulsion films associated with bubble-bubble and drop-drop coalescence phenomena. The present analysis extends the earlier work of Zapryanov et al(1983) and of others which was limited to the diffusion controlled case of the surfactant transport from the bulk phase onto the interface. Here the surfactant transport from the bulk phase to the interface is accounted for by a two step mechanism: (i) diffusion of the surfactant from the bulk to the sublayer, followed by (ii) the adsorption of the surfactant from the sublayer onto the interface. The results of a parametric study indicate that the rate of drainage of surfactant stabilized films is strongly dependent upon the surfactant adsorption-desorption kinetics, selective surfactant solubility, and interfacial Theological properties such as elasticity and interfacial viscosity. Predictions of the film drainage time are compared with our experimental d...
Improved methods of tablet coating

This paper describes an attempt to develop a standardized method of tablet coating; i.e., the application of well-defined procedures of precise quantities of liquids and solids to a definite weight or volume of tablets. Experiments presented show that the standardization of tablet coating is possible. The disintegration tests show that the tablets coated by the outlined processes disintegrate rapidly.
Conceiving or Misconceiving the Self: Issues in Adolescent Self-Esteem

An individual cannot touch, smell, taste, hear, or see self-esteem. The self is not a "natural" phenomenon and is thus not accessible to the same kinds of scientific inquiry and measurement as are natural psychological constructs that are observable (e.g., human motor behavior). Self-esteem is nonsensical-cannot be measured through sensory data collection-and hence imaginary (Berlow, personal communication); as a result, an individual's self-esteem must be inferred, either by an individual's report of his/her sense of self (experienced self) or by others reporting the individual's self-esteem (presented self). But the social science community has too readily accepted an individual's personal self-report of self-esteem as natural fact. The guiding, and unquestioned assumption has been that the individual alone has access to the self. Who are we as outsiders to question this source of data? Few self-esteem researchers have used "others" to infer self-esteem-and thus they have relatively little knowledge of the validity of their self-report data (Wells & Marwell, 1976).
A Comparison of the Smith Predictor and Optimal Design Approaches for Systems with Delay in the Control

The relatively recent application of optimal control theory to the design of control systems for processes with delay has made available an alternative design approach to the classical Smith Predictor approach. Although the designs resulting from the two approaches have many features in common, there are also important differences, and neither the similarities or differences have been examined in any detail in the literature. This paper surveys the work to date in this area, reviews the development of and examines the general characteristics of the control systems resulting from application of the two approaches to a general class of multivariable systems with delay in the control, and presents a detailed comparison of the designs for the case in which the process to be controlled is first order with delay. An important result which emerges is that the design resulting from the optimal approach as developed in the literature to date does not perform as well as the Smith Predictor design in controlling against output disturbances.
A note on discontinuous time changes of Markov processes

Abstract The “time change” of a Markov process via the inverse of a discontinuous additive functional A t can be accomplished in two steps. First, perform a time change via the inverse of the strictly increasing discontinuous additive functional obtained by replacing the continuous part of A t by t . The second step is an ordinary time change via the inverse of a continuous additive functional. Decomposing the time change in this way is useful in studying the time changed process.
Mastering Master Mind logically

Some readers of the recent note by Ehud Shapiro on "Playing Master Mind Logically" (SIGART 85, July 1983) may reasonably have concluded that Prolog was a suitable language for a "generate and test" strategy, as the author stated, but that perhaps there was something intrinsic to Prolog that made anything much more subtle unwieldy. The present note at any rate shows how a more "logical" strategy incorporating that previously described may readily be implemented without compromising the elegance and simplicity of Ehud Shapiro's original problem. A related approach, using templates as generators, is also described.
Engineered nanomaterial interactions with bilayer lipid membranes: screening platforms to assess nanoparticle toxicity

Engineered nanomaterials (ENMs) have attractive functional properties and are increasingly being used in commercial products. However, ENMs present health risks that are poorly understood and difficult to assess. Because ENMs must interface with cell membranes to cause biological effects, improved methods are needed to measure ENM-biomembrane interactions. The goals of this paper are to review the current status of methods to characterise interactions between ENMs and bilayer lipid membranes that mimic cell membranes, and to present example applications of the methods relevant to nanotoxicology. Four approaches are discussed: electrochemical methods that measure ENM-induced ion leakage through lipid bilayers, optical methods that measure dye leakage from liposomes, partitioning methods that measure ENM distribution coefficients between aqueous solution and immobilised lipid bilayers, and theoretical models capable of predicting fundamental molecular interactions between ENMs and biomembranes. For each approach, current literature is summarised, recent results are given, and future prospects are analysed, including the potential to be used in a high-throughput mode. The relative advantages of the various approaches are discussed, along with their synergistic potential to provide multi-dimensional characterisation of ENM-biomembrane interactions for robust health risk assessment algorithms.
Germinal aging in Tetrahymena thermophila

Abstract The manifestations of germinal aging in the ciliate Tetrahymena thermophila include death of the cells at conjugation and macronuclear retention in which the normal replacement of the old macronucleus by a new one fails to occur. Available data suggest that methods of routine maintenance that reduce the number of fissions may delay aging. Differences in breeding performance following maintenance for 1–5 years in axenic peptone broth vs. bacterized Cerophyl were not significant; those following maintenance at different temperatures were significant. The analysis of several hundred crosses is consistent with a random mutational basis for aging in the micronucleus and does not support the hypothesis of an age-correlated program in which the rate of deterioration increases with time. Following routine cultural maintenance for as long as 9–11 years, some lines show no deficiencies in their ability to produce viable progeny, and sublines of the same clone frequently differ significantly in their breeding performance. Moreover, breeding degeneration occurs at constant, but different, rates in different inbred strains.
Human Action Recognition in Large-Scale Datasets Using Histogram of Spatiotemporal Gradients

Research in human action recognition has advanced along multiple fronts in recent years to address various types of actions including simple, isolated actions in staged data (e.g., KTH dataset), complex actions (e.g., Hollywood dataset) and naturally occurring actions in surveillance videos (e.g, VIRAT dataset). Several techniques including those based on gradient, flow and interest-points have been developed for their recognition. Most perform very well in standard action recognition datasets, but fail to produce similar results in more complex, large-scale datasets. Here we analyze the reasons for this less than successful generalization by considering a state-of-the-art technique, histogram of oriented gradients in spatiotemporal volumes as an example. This analysis may prove useful in developing robust and effective techniques for action recognition.
p-Iodobenzoyl groups as a paired label for in vivo protein distribution studies; specific localization of anti-tissue antibodies.

Abstract Measurements of the specific in vivo localizing properties of radiolabeled anti-tissue antibodies are always complicated by the nonspecific pickup of proteins by tissues. Beacause of the affinity of tumors for foreign proteins, the determination of the specific localization of anti-tumor antibodies is particularly difficult. We have developed the paired label technique for the direct measurement of the quantity of antibody and control protein localized in each tissue sample. The experimental subject serves as its own control. The globulin fraction of the antiserum is labeled with one radioisotope and the globulin fraction of normal serum is labeled with another isotope and the preparations are injected simultaneously. The distribution of both proteins is then determined by differential analysis of the two isotopes. In order to avoid the possibility that chemical differences in the labeled proteins will lead to alterations in the nonspecific distribution of one or the other protein, we have restricted ourselves to the use of label pairs which differ only isotopically. A previous report dealt with the direct iodination of proteins using I 131 and I 133 as a paired label. The work reported here describes the use of p -iodobenzoyl groups containing I 131 and I 14 for paired labeling in experiments of long duration where the short half-life of I 133 precludes the use of the iodine paired label.
RELEASE OF STORED ENERGY IN OXIDE-DISPERSION-STRENGTHENED COPPER

The pattern of energy release on annealing was followed by calorimetric means for a series of oxide-dispersion-strengthened copper alloys extruded at high reduction ratio. Included among the test materials were two Cu-Al2O3 alloys prepared by salt decpmposition, several Cu-SiO2 and Cu-Al2O3 alloys prepared by internal oxidation, and a CU-CU2O alloy prepared by surface oxidation. For several of the alloys energy releases were observed that confirm the expected high levels of energy stored during high strain rate extrusion. Values of 0·41 and 0·42 cal/g were measured and correspond to levels of cold work found in copper severely deformed in torsion. The energy release was observed at temperatures high above that normal for the recrystallization of cold-worked copper.
The structure and dynamics of alkali silicate liquids: A view from NMR spectroscopy

Abstract Understanding and predicting the macroscopic properties of silicate liquids require information on both structure and dynamics. Studies of glass structure provide a convenient starting point, but only represent the liquid at the rather low temperature of transition from glass to liquid. In situ high- T studies, as well as work on glasses with varying fictive temperature, can provide more information on structural changes with T and on dynamical mechanisms. Here we discuss the application of NMR spectroscopy to both kinds of approaches. We present results, primarily from our laboratory, on anionic species distributions, on silicon and oxygen site exchange in liquids and its relationship to viscosity, and on the quantification of the abundances of five- and six-coordinated Si in high-pressure and 1-bar-pressure glass samples.
Interplay between HIV-1 Vpr and Sp1 Modulates p21WAF1 Gene Expression in Human Astrocytes

The Vpr (viral protein R) of human immunodeficiency virus, type 1, which is expressed during the late stage of the viral infection, has received special attention because of its ability to control transcription of the human immunodeficiency virus, type 1, long terminal repeat and to influence cell cycle progression. Here we demonstrate that Vpr has the ability to regulate transcription of the cyclin-dependent kinase inhibitor, p21WAF1 (p21), one of the key regulators of the cell cycle, in human astrocytic cells. The results from transcription assays demonstrated that Vpr augments promoter activity of p21 through the GC-rich region located between nucleotides -84 and -74 with respect to the +1 transcription start site. Activation of p21 by Vpr required cooperativity of Sp1, which binds to the DNA sequence spanning -84 to -74. Results from bandshift assay revealed an increased level of Sp1 DNA binding activity in the presence of Vpr. Furthermore, Vpr was able to associate with Sp1 via the zinc finger domain located in the C-terminal region of Sp1. Functional studies revealed that the cooperativity between Vpr and Sp1 requires the zinc finger domain at the C terminus and the glutamine-rich domain at the N terminus of Sp1. Expression of p53 further enhanced the level of Vpr-Sp1-mediated transcription activation of p21 through the sequence spanning -84 to -74 and increased the DNA binding activity of Sp1 in the presence of Vpr. Results from glutathione S-transferase pull-down assay showed the association of Vpr with p53 in extracts containing Sp1. Altogether, the outcome of our functional and binding studies suggested that the physical interaction of Vpr with Sp1 and p53 could modulate transcriptional activity of p21.
The secant method and fixed points of nonlinear operators

Our results answer the following question: given that a mapping has a fixed point, when is it true that the Secant iterates produce a sequence of nearby points which converge to the fixed point? We assume only that the nonlinear operator has a Holder continuous Frechet-derivative at the fixed point.
Witness for Freedom: African American Voices on Race, Slavery, and Emancipation

Encompassing a broad range of African American voices, from Frederick Douglass to anonymous fugitive slaves, this collection collects eighty-nine exceptional documents that represent the best of the five-volume Black Abolitionist Papers . In these compelling texts African Americans tell their own stories of the struggle to end slavery and claim their rights as American citizens, of the battle against colonization and the "back to Africa" movement, and of their troubled relationship with the federal government.
The Globalization of Cow's Milk Production and Consumption: Biocultural Perspectives

Cow's milk consumption has been relatively rare in human history, largely confined to populations with genetic adaptations for continued production of lactase, the enzyme that breaks down the unique milk sugar lactose. But in the last forty years, both the production and consumption of cow's milk have spread around the world, and trade in milk products has likewise increased. Populations with no history of milk drinking have embraced this new beverage, and governments promote its consumption in their food-based dietary guidelines and school milk programs. China is a particularly good example of this trend. There the dairy industry is growing rapidly and milk consumption has become increasingly common in urban areas. Milk is viewed as especially appropriate for children, with growth-promoting properties; the larger size and athletic success of western athletes is often attributed to their greater milk consumption. Milk is a very unusual food insofar as it is uniquely produced by mammals to support the grow...
Partitioning of Polychlorinated Dibenzo-p-dioxins and Dibenzofurans between the Atmosphere and Corn

Polychlorinated dibenzo-p-dioxins (PCDD) and polychlorinated dibenzofurans (PCDF) are lipophilic atmospheric contaminants that accumulate in vegetation, a process which may lead to the contamination of food. Thus, knowledge of PCDD/F accumulation in vegetation is crucial to evaluating human exposure. In an effort to determine this accumulation mechanism, the authors analyzed matched atmosphere, corn kernel, and corn leaf samples from a private farm in Felicity, OH. Corn is an important feed crop in the US; both corn kernels and corn leaves (silage) are widely used. PCDD/F concentrations were below the detection limits in the corn kernels. However, they found PCDD/F concentrations of 510 {+-} 75 fg/m{sup 3}, 1,300 {+-} 300 fg/m{sup 3}, and 4.2 {+-} 1.2 ng/g lipids in the atmospheric gas phase, atmospheric particle phase, and corn leaves, respectively. For each set of air and corn leaf samples, the authors calculated corn leaf-atmosphere partition coefficients for both the atmospheric gas and particle phases, K{sub v,g} and K{sub v,p}, respectively. On the basis of plots of the natural logarithm of these partition coefficients versus the reciprocal of the average, atmospheric temperature, they conclude that the partitioning of PCDD/F between the atmosphere and corn leaves is dependent on temperature. They calculated the enthalpiesmore » of phase change between the vegetation and air for all PCDD/F homologues; the values are comparable to literature values for polycyclic aromatic hydrocarbons and polychlorinated biphenyls. The ratio of K{sub v,p} to K{sub v,g} is a log-log function of the average vapor pressure for each PCDD/F homologue, indicating that vapor pressure plays an important role in the partitioning of both the gas and particle phases to corn leaves.« less
Paper vs. electrons. Epidemiologic publishing in a changing world.

Abstract PURPOSE: To present the parallel histories of epidemiologic and electronic publishing and consider positive and negative factors that might affect their amalgam. METHODS: We performed a quantitative assessment of the arc of epidemiologic publication from 1966–1999, using major self-designated epidemiologic journals as a sample, and of scholarly electronic publication from 1991–1997, based on current literature review. We use an online, paperless journal as a case study, and review selected information-technology opinion in the area. RESULTS: By traditional standards, growth in epidemiologic publication has been considerable, with the addition of six new journals since 1966. In contrast, scholarly electronic publication for the period 1991–1997 grew from 27 to 2459 journals (not all exclusively online). Positive features of electronic publishing include flexibility, shortened time to publication, freedom from fixed publication date, diversity in presentation, and instant linkage to relevant material. A case study of a new online journal illustrates the substantive power of the medium. Negative factors include restriction (or unrestricted expansion) of the audience, the potential for hasty peer review, pitfalls in establishing credibility, an emphasis on style over content, technologic dependence, and additions to the information explosion. Relative cost and archiving are still debated. In assessing the pros and cons, it is important to distinguish electronic mechanisms that facilitate publication from electronic publishing, and to appreciate the difference between moving an existing journal to the electronic medium, and creating a new online journal. CONCLUSIONS: The movement from print to internet is probably inexorable, but a headlong rush may be ill-advised. Several models for dual publishing now exist, with the expectation that many, including the journals that serve epidemiology, will do so. The ultimate configuration is difficult to predict, but likely to be shaped in large measure by market forces, technologic advances and to a lesser extent, by habit and aesthetics.
Synthesis of mucosa and lymph phospholipide during fat absorption.

Summary and ConclusionComparison of the relative specific activities of the glycerol of lymph triglycerides and phospholipides from previous studies, and of intestinal mucosa phospholipides from new studies demonstrated that resynthesized triglycerides must be the precursors of mucosa and lymph phospholipides, rather than the converse.
Quantifying rolling adhesion with a cell-free assay: E-selectin and its carbohydrate ligands

Rolling of neutrophils over stimulated endothelial cells is a prerequisite to firm attachment and subsequent transendothelial migration during the inflammatory response. The selectin family of adhesion molecules are thought to mediate rolling by binding counter-receptors that present carbohydrates, such as sialyl Lewis(x) (sLe[x]). Recently we described a cell-free system for rolling using sLe(x)-coated microspheres and E-selectin molecules on inert substrates. We showed that sLe(x)-coated microspheres rolled over E-selectin-IgG chimera substrates with dynamics that are similar to those of leukocytes rolling over stimulated endothelium. In this paper we provide a thorough quantitative description of the dynamics of adhesion for this system. We find that particle rolling velocity increases with increasing wall shear stress and decreases with increasing E-selectin or sLe(x) surface densities. Large changes in the average rolling velocity can occur with small changes in sLe(x) or E-selectin density; however, rolling velocity is more sensitive to E-selectin surface coverage than to the number of sLe(x) molecules on the microspheres. Aided by dimensional analysis, we show that decreasing the wall shear stress or increasing either receptor (E-selectin) or ligand (sLe[x]) surface coverage results in an equivalent decrease in particle rolling velocity. In addition, we find that different Lewis carbohydrates are more effective in mediating rolling on E-selectin, with effectiveness following the trend sialyl Lewis(a) > sialyl Lewis(x) >> sulfated Lewis(x) >> Lewis(x). Rolling velocity fluctuated with time for all carbohydrate-selectin pairs tested, and the magnitude of the velocity fluctuations was linearly proportional to the mean rolling velocity for all combinations of E-selectin site density, sLe(x) site density, wall shear stress, and carbohydrate chemistry tested.
Neural correlates of individual differences related to appetite

Using neuroimaging technologies to compare normal weight and obese individuals can reveal much about the pathophysiological state of obesity but such comparisons tell us little about what makes some normal weight individuals susceptible to obesity or about important individual differences amongst obese individuals. The current review therefore reviews neuroimaging research on individual difference measures that can illuminate these important topics. After introducing three neuropsychological models of the nature of motivation to approach rewarding stimuli, neuroimaging research on measures of impulsivity, craving, binge eating, restrained eating and disinhibited eating is reviewed. Although neuroimaging research on individual differences measures of brain activity related to appetite is in its infancy, existing studies suggest that such research could enrich the understanding, prevention and treatment of disordered eating and obesity.
Catalysis and kinetics of cyclotrimerization of cyanate ester resin systems

The kinetics of cyclotrimerization and the thermal stability of bisphenol Abased cyanate ester resin systems were determined using Fourier transform infrared spectroscopy, differential scanning calorimetry, and thermogravimetry. The bisphenol A dicyanate was cured with 4 phr nonylphenol and with the octoates of zinc and manganese, and cobalt acetylacetonate at concentrations ranging from 0 to 750 ppm metal. An empirical rate law was used to predict the cyanate concentration profiles. The observed reaction rate showed a first-order dependence on the initial metal concentration and a second-order dependence on the cyanate concentration in the kinetically controlled regime. For the uncatalyzed systems, the kinetics was described by a second-order autocatalytic model. The thermal stability of the network was found to be dependent on the catalyst concentration for the zinc catalysts. For the samples cured with manganese, no effect of concentration on the thermal stability was observed.
Ubiquitous Amplification: Applications of the Semiconductor Optical Amplifier

Many new system architectures are enabled if low-cost amplifiers can be used ubiquitously to compensate for transmission and component losses. Here we discuss the possible impact of the semiconductor optical amplifier on next-generation networks.
Structure of aggregated gold colloids.

We report a high-resolution, small-angle x-ray study of aggregated gold colloids over the range 0.0003 to 0.08 ${\mathrm{\AA{}}}^{\ensuremath{-}1}$. We are able to fit our data with a simple model that correctly accounts for nonfractal short-range order with a crossover to long-range fractal correlations. This provides new information on the structure of real aggregates, and new insight into the aggregation processes which lead to their formation.
The use of visual feedback for the acquisition of pseudorandomly oriented parts

The problem of picking up single cylindrical objects using a robot equipped with a vision system is investigated. Explanation of how the robot defines the position of objects located within the workcell is provided. Image analysis, camera calibration, and algorithm specification are also defined.
Online Identification of Dwell Regions for Moving Objects

A region R is a dwell region for a moving object O if, given a threshold distance d and duration t, every point of R remains within distance d of O for at least time t. Clearly, points within R are likely to be of interest to O, so identification of O and R has applications in areas such as monitoring and surveillance, as well as to trajectory simplification. We propose an online algorithm to solve this problem, which can handle dynamic addition and deletion of data in logarithmic time. We assume an incoming stream of object positions, and maintain the upper and lower bounds for the radius of the smallest circle enclosing these positions, as points are added and deleted. These bounds allow us to greatly reduce the number of trajectory points we need to consider in the query, as well as to defer query evaluation. Our method can approximate the radius of the smallest circle enclosing a given sub trajectory within an arbitrarily small user defined factor. Our experiments show that the proposed method can scale up to hundreds of thousands of trajectories.
On some generalized farlie-gumbel-morgenstern distributions-II regression, correlation and further generalizations

Regression and correlation properties of the generalized Farlie-Gumbel-Morgenstem distributions introduced in Johnson and Kotz (1975) are studied. Further generalizations of these distributions are considered.
Craniofacial approaches to tumors of the anterior skull base

An approach that combines extracranial and intracranial components-termed a craniofacial approach-allows en bloc extirpation of paranasal malignancies that abut or penetrate the skull base. When combined with radiotherapy, cure rates for such tumors rose from near zero in the 1950s to 39% to 86% by 2000, with the higher rates reflective of esthesioneuroblastomas, well-differentiated adenocarcinomas, vasoformative tumors, and meningiomas. Transfacial tumor access can involve a transnasal (endoscopic or with magnification loupes) exposure, a midfacial degloving, or a lateral rhinotomy, depending on tumor location and size. Adjunctive exposures for tumors penetrating the nasopharynx, pterygomaxillary fossa, or sphenoid include the lateral facial split and the mandibular swing. The standard transcranial accesses are a sub-basal variation of frontal craniotomy, which encompasses en bloc the superior orbital rims, the nasion, and the lower frontal bones; or, a frontotemporal craniotomy with mobilization of the lateral orbital rim and the zygoma.
Early mortality and cardiorespiratory failure in patients with fibrodysplasia ossificans progressiva.

Fibrodysplasia ossificans progressiva (Mendelian Inheritance in Man [MIM] #135100) is a rare, disabling genetic disorder of progressive heterotopic ossification caused by a heterozygous activating mutation of the gene encoding activin receptor A type I/activin-like kinase 2 (ACVR1/ALK2), a bone morphogenetic protein (BMP) type-I receptor, in all classically affected individuals worldwide1-4. There is no racial, ethnic, sex, or geographic predilection5. While disease flare-ups in fibrodysplasia ossificans progressiva are episodic, disability is cumulative3,6. Most patients are confined to a wheelchair by the third decade of life6,7. Clinical management is symptomatic, and there is no effective treatment3,8. While much is known about the disabling complications of this disease, documentation of lifespan and causes of death in these patients have not been examined. We undertook a comprehensive study to determine the lifespan and cause of death in individuals with fibrodysplasia ossificans progressiva.
Laser embedding electronics on 3D printed objects

Additive manufacturing techniques such as 3D printing are able to generate reproductions of a part in free space without the use of molds; however, the objects produced lack electrical functionality from an applications perspective. At the same time, techniques such as inkjet and laser direct-write (LDW) can be used to print electronic components and connections onto already existing objects, but are not capable of generating a full object on their own. The approach missing to date is the combination of 3D printing processes with direct-write of electronic circuits. Among the numerous direct write techniques available, LDW offers unique advantages and capabilities given its compatibility with a wide range of materials, surface chemistries and surface morphologies. The Naval Research Laboratory (NRL) has developed various LDW processes ranging from the non-phase transformative direct printing of complex suspensions or inks to lase-and-place for embedding entire semiconductor devices. These processes have been demonstrated in digital manufacturing of a wide variety of microelectronic elements ranging from circuit components such as electrical interconnects and passives to antennas, sensors, actuators and power sources. At NRL we are investigating the combination of LDW with 3D printing to demonstrate the digital fabrication of functional parts, such as 3D circuits. Merging these techniques will make possible the development of a new generation of structures capable of detecting, processing, communicating and interacting with their surroundings in ways never imagined before. This paper shows the latest results achieved at NRL in this area, describing the various approaches developed for generating 3D printed electronics with LDW.
Raman and infrared spectra, structure, vibrational assignment, normal coordinate analysis, and ab initio calculations of trifluoromethyl isocyanate

Abstract The Raman (2500 to 30 cm −1 ) and infrared (2500 to 60 cm 1 ) spectra of gaseous and solid trifluoromethyl isocyanate, CF 3 NCO, have been recorded. The Raman spectrum of the liquid has also been obtained and qualitative depolarization ratios have been measured. The CNC bend has been observed in the low-frequency Raman spectrum of the gas at 130 cm −1 as a relatively strong line which is split in the spectrum of the solid. However, the CF 3 torsional mode was not observed. The infrared spectrum of CF 3 NCO dissolved in liquid xenon was also obtained and the observed spectrum indicates a very small barrier to internal rotation. With the exception of the torsion, a complete assignment of the vibrational fundamentals is proposed. The structural parameters, force constants, and vibrational frequencies have been determined from ab initio calculations utilizing a variety of basis sets and the theoretical results are compared to the experimental values when appropriate. These results have been compared with the corresponding quantities obtained for some similar molecules.
Dissolution of the maskin–eIF4E complex by cytoplasmic polyadenylation and poly(A)-binding protein controls cyclin B1 mRNA translation and oocyte maturation

Cytoplasmic polyadenylation stimulates the translation of several dormant mRNAs during oocyte maturation in Xenopus. Polyadenylation is regulated by the cytoplasmic polyadenylation element (CPE), a cis-acting element in the 3′-untranslated region of responding mRNAs, and its associated factor CPEB. CPEB also binds maskin, a protein that in turn interacts with eIF4E, the cap-binding factor. Here, we report that based on antibody and mRNA reporter injection assays, maskin prevents oocyte maturation and the translation of the CPE-containing cyclin B1 mRNA by blocking the association of eIF4G with eIF4E. Dissociation of the maskin–eIF4E complex is essential for cyclin B1 mRNA translational activation, and requires not only cytoplasmic polyadenylation, but also the poly(A)-binding protein. These results suggest a molecular mechanism by which CPE- containing mRNA is activated in early development.
Almost sure stability of dynamical systems under combined harmonic and stochastic excitations

Abstract The almost sure asymptotic stability and the associated sample behavior of mechanical and structural systems under combined harmonic and stochastic excitations are examined. The method of extended stochastic averaging developed by the author is used to obtain a lower-dimensional Markov processes for multi-degree-of-freedom structures subjected to both harmonic and stochastic excitations, provided that the intensities of these excitations are small. The approach in this paper formulated for the study of almost sure asymptotic stability is based on the well-developed concept of Lyapunov exponents. The largest Lyapunov exponent is obtained explicitly by using the lower-dimensional approximate Ito equations. The results from this analysis are applied to study the almost sure asymptotic stability of uncoupled flapping motion of rotor blades in forward flight under the effect of atmospheric turbulence.
The specific mutagenic effect of base analogues on Phage T4

Several purine and pyrimidine analogues which are sterically very similar to the normal nucleic acid bases have been tested for their mutagenic effect upon T4 phages. Besides 5-bromodeoxyuridine only 2-aminopurine and 2,6-diaminopurine were effective. Most of the base analogues tested inhibit bacterial growth when present in sufficiently high concentrations, and some of them show an additional effect upon phage growth. Thus 5-bromodeoxyuridine and 5-bromouracil inhibit phage growth (especially in the derivatives of bacteria K-12), and 2-aminopurine depresses lysis inhibition under certain growth conditions. The “mutability spectrum” of T4 rII-type phage mutants induced by 5-bromo-deoxyuridine was found to be essentially the same as that of 5-bromouracil-induced mutants studied by Benzer & Freese (1958) . In contrast, the mutability spectrum of 2-aminopurine-induced mutants was different from both spontaneous and bromouracil-induced mutants. The genetic coincidence, however, of some 2-aminopurine-induced mutants with some bromouracil-induced mutants indicates some mutagenic similarity between the two base analogues. The high frequency of phage mutants after growth in the presence of the base analogue is not due to selection of pre-existing mutants, as shown by a fluctuation test. Again, the differences between the mutability spectra are not due to any selection but are caused by preferential mutagenic actions at certain sites of the genome.
Early experience with ASDL in 1cc

The Abstract Syntax Description Language (ASDL) is a language for specifying the tree data structures often found in compiler intermediate representations. The ASDL generator reads an ASDL specification and generates code to construct, read and write instances of the trees specified. Using ASDL permits a compiler to be decomposed into semi-independent components that communicate by reading and writing trees. Each component can be written in a different language, because the ASDL generator can emit code in several languages, and the files written by ASDL-generated code are machine- and language-independent. ASDL is part of the National Compiler Infrastructure project, which seeks to reduce dramatically the overhead of computer systems research by making it much easier to build high-quality compilers. This paper describes dividing lcc, a widely used retargetable C compiler, into two components that communicate via trees defined in ASDL. As the first use of ASDL in a ‘real’ compiler, this experience reveals much about the effort required to retrofit an existing compiler to use ASDL, the overheads involved, and the strengths and weaknesses of ASDL itself and, secondarily, of lcc. Copyright © 1999 John Wiley & Sons, Ltd.
Tuning in to the rhythm: The role of coping in strategic management of work-life conflicts in the public relations profession

Abstract How public relations practitioners cope with work-life conflict was studied through a national survey of a random sample of PRSA (Public Relations Society of America) members. These active practitioners reported strong preferences in using more proactive conflict coping strategies, such as rational action and positive thinking. Women and those with a graduate degree tend to report more coping behaviors than others. Three types of stressors are identified as sources of work-life conflict: behavior-driven, work-driven, and life-driven. According to our findings, while behavior-driven work-life stressors are associated with proactive coping strategies such as rational action and positive thinking, work-driven stressors tended to trigger more avoidance. Non-work driven stressors seem to predict more passive coping tendencies, such as denial and avoidance. Organizational factors are found to be important in understanding how practitioners cope with work-life conflict. As organizational demands increased to separate life from work, more instructions seemed necessary for employees to better cope with work-life conflicts. Positive thinking, as a type of cognitive coping, tends to increase when there is more immediate supervisor support and to decrease when an organization's work-life culture is skewed toward promoting work as the sole priority.
Noise-induced hearing loss in young adults: The role of personal listening devices and other sources of leisure noise

Concept: No consensus exists regarding the magnitude of the risk of noise-induced hearing loss (NIHL) associated with leisure noise, in particular, personal listening devices in young adults. Objective: Examine the magnitude of hearing loss associated with personal listening devices and other sources of leisure noise in causing NIHL in young adults. Study Design: Prospective auditory testing of college student volunteers with retrospective history exposure to home stereos, personal listening devices, firearms, and other sources of recreational noise. Methods: Subjects underwent audiologic examination consisting of estimation of pure-tone thresholds, speech reception thresholds, and word recognition at 45 dB HL. Results : Fifty subjects aged 18 to 30 years were tested. All hearing thresholds of all subjects (save one-a unilateral 30 dB HL threshold at 6 kHz) were normal, (i.e., 25 dB HL or better). A 10 dB threshold elevation (notch) in either ear at 3 to 6 kHz as compared with neighboring frequencies was noted in 11 (22%) subjects and an unequivocal notch (15 dB or greater) in either ear was noted in 14 (28%) of subjects. The presence or absence of any notch (small or large) did not correlate with any single or cumulative source of noise exposure. No difference in pure-tone threshold, speech reception threshold, or speech discrimination was found among subjects when segregated by noise exposure level. Conclusion: The majority of young users of personal listening devices are at low risk for substantive NIHL. Interpretation of the significance of these findings in relation to noise exposure must be made with caution. NIHL is an additive process and even subtle deficits may contribute to unequivocal hearing loss with continued exposure. The low prevalence of measurable deficits in this study group may not exclude more substantive deficits in other populations with greater exposures. Continued education of young people about the risk to hearing from recreational noise exposure is warranted.
Learning Abstract Concepts: The Use of Analogies as a Mediational Strategy.

This paper examines the differences between concrete and abstract concepts and the implications of those differences for instructional design and teaching. The use of analogies is suggested as an instructional tool in abstract concept learning. Using the published literature on concept learning and analogies, the authors examine how specific concepts are stored in and retrieved from memory, the particular problems presented in learning abstract concepts, and how analogies mediate between the vague, intangible attributes of abstract concepts and those of a more concrete nature. Finally, they present a possible instructional strategy for teaching abstract concepts.