cssi/SciSciGPT-SciSciNet huggingface dataset:
Novel Insights into the Maturation and Enucleation of Primitive Erythroblasts.

Abstract Primitive erythroblasts (EryP), the first blood cell type to form during mammalian embryogenesis, arise in the yolk sac (YS) as a synchronous cohort before the establishment of the embryonic circulation. The large, nucleated EryP begin to circulate around midgestation, when connections between YS and embryo mature. Two to three days later, small cells of the definitive erythroid lineage (EryD) begin to differentiate within the fetal liver and rapidly outnumber EryP within the circulation. Cells of the two erythroid lineages differ not only in size but also in their expression of globin genes. Recently it has been shown that EryP begin to enucleate around E12.5 in the mouse. We have begun to characterize EryP maturation during mouse embryogenesis, with a focus on circulating cells. Analysis of embryonic blood at different stages revealed a stepwise developmental progression within the primitive erythroid lineage: loss of nucleoli (E9.5–10.5); decrease in cell diameter and cross-sectional area (E10.5–11.5); progressive nuclear condensation (E10.5 onwards); and enucleation (E12.5 onwards). Thereafter, EryD are also present in the bloodstream. A major obstacle to the study of primitive erythroid development is the current inability to easily distinguish EryP from EryD and to cleanly separate these populations, particularly given that enucleation can no longer be considered an exclusively definitive erythroid characteristic. No EryP-specific surface antigens have been identified that would permit the detection and isolation of cells of this lineage. We have exploited the restricted expression of the human embryonic beta-like globin gene epsilon to generate EryP lineage-specific transgenic mouse and embryonic stem (ES) cell models in which green fluorescent protein (GFP) reporter expression is driven exclusively in EryP and have used this line to track quantitatively the differentiation and maturation of circulating EryP during embryogenesis. The maturation of primitive erythroblasts was reflected in their dynamic expression of Ter119 and CD71. Up-regulation of a number of nonerythroid-specific cell surface markers, including integrins and other adhesion molecules, was apparent beginning around E12.5, reflecting a previously unrecognized EryP maturation process. Interestingly, enucleation of EryP is accompanied by changes in surface antigen expression. Thus, the phenotype of primitive reticulocytes is distinct from that of their nucleated precursors. In contrast with the prevailing view that EryP are present only transiently in the embryo, we find that they comprise a stable cell population that persists through the end of gestation. The human epsilon-globin::GFP transgenic mouse model provides a novel system for defining, at the cellular and molecular level, the mechanisms involved in development of the primitive erythroid lineage.
Should Networks Supplant Tree Building

Recent studies suggested that network methods should supplant tree building as the basis of genealogical analysis. This proposition is based upon two arguments. First is the observation that bacterial and archaeal lineages experience processes oppositional to bifurcation and hence the representation of the evolutionary process in a tree like structure is illogical. Second is the argument tree building approaches are circular-you ask for a tree and you get one, which pins a verificationist label on tree building that, if correct, should be the end of phylogenetic analysis as we currently know it. In this review, we examine these questions and suggest that rumors of the death of the bacterial tree of life are exaggerated at best.
Introduction of a new scheme for classifying β-turns in protein structures.

Protein β-turn classification remains an area of ongoing development in structural biology research. While the commonly used nomenclature defining type I, type II and type IV β-turns was introduced in the 1970s and 1980s, refinements of β-turn type definitions have been introduced as recently as 2019 by Dunbrack, Jr and co-workers who expanded the number of β-turn types to 18 (Shapovalov et al, PLOS Computat. Biol., 15, e1006844, 2019). Based on their analysis of 13 030 turns from 1074 ultrahigh resolution (≤1.2 A) protein structures, they used a new clustering algorithm to expand the definitions used to classify protein β-turns and introduced a new nomenclature system. We recently encountered a specific problem when classifying β-turns in crystal structures of pentapeptide repeat proteins (PRPs) determined in our lab that are largely composed of β-turns that often lie close to, but just outside of, canonical β-turn regions. To address this problem, we devised a new scheme that merges the Klyne-Prelog stereochemistry nomenclature and definitions with the Ramachandran plot. The resulting Klyne-Prelog-modified Ramachandran plot scheme defines 1296 distinct potential β-turn classifications that cover all possible protein β-turn space with a nomenclature that indicates the stereochemistry of i + 1 and i + 2 backbone dihedral angles. The utility of the new classification scheme was illustrated by re-classification of the β-turns in all known protein structures in the PRP superfamily and further assessed using a database of 16 657 high-resolution protein structures (≤1.5 A) from which 522 776 β-turns were identified and classified.
The Dzokchen Apology: On the Limits of Logic, Language, & Epistemology in Early Great Perfection

This article examines the translator, Rongzom’s (fl. late 11th/early 12th c.), scholastic philosophical defense of early Dzokchen (rdzogs pa chen po) or “Great Perfection.” As our earliest instance of religious apologia in Tibet, this examination contributes to a growing body of knowledge about the Tibetan assimilation of post-tenth century of Vajrayāna Buddhism and the indigenous response to the forces of cultural transformation shaping the late eleventh/early twelfth century Tibet. Traditional authorities and academics have identified Dzokchen as a Tibetan tradition of Buddhism that drew intense criticism at the time from renaissance agents. This paper explores the primary Tibetan response by describing Rongzom’s philosophical defense of Great Perfection. As such, it illuminates the intellectual and ideological context of the milieu as it evinces Rongzom’s innovation and mastery of Indian systems of logic, language, and epistemology in the Dzokchen approach to the Buddhist path.
The ovine fetoplacental endocrine response to placental damage.

Abstract In the chronic pregnant ewe preparation, daily blood samples, for the determination of plasma cortisol and progesterone levels by specific radioimmunoassay, were obtained from the fetal distal aorta, uterine vein, and uterine artery prior to, during, and after repetitive embolization of the uterine circulation with 15 μ microspheres. A significant increase in fetal cortisol was observed in all animals during the first 3 days of embolization. In those which subsequently entered premature labor, this increase was progressive and was associated with a fall in the uterine venous progesterone level but was unrelated to changes in either the maternal cortisol level or fetal physiologic parameters. In animals which did not enter premature labor, progesterone levels in the uterine vein and estimated progesterone release rates were elevated with an accentuated peak-trough pattern during the postembolization period. In these animals fetal cortisol returned to control levels. The data suggest that cortisol and progesterone biosynthesis within the fetoplacental unit is altered by microembolic placental damage.
De cómo Ramón Gómez de la Serna se convirtió en un fan de Twitter: un ejemplo de textualteridad digital

Gracias al concepto de textualteridad defendido por Joseph Grigely, entendemos la edicion de una obra literaria como un evento unico que se actualiza en el momento, lugar, circunstancias y publico de la edicion misma, ademas de cada acto particular de lectura. Quiero exponer un ejemplo teorico-practico de edicion online que se explica bien en el contexto de la actual cultura de la convergencia defendida por Henry Jenkins. Demostrare como el Total de Greguerias (1955) de Ramon Gomez de la Serna, adaptado al medio digital y sus mecanismos de lectura, explora bien tres tipos de interactividad basicos del medio: la interaccion hipertextual, la inmersiva y la registracional. Se crea asi una edicion de lectura de caracter no lineal, multimodal, y social, ademas de rigurosamente academica, que reinterpreta el texto literario como cibertexto y lo integra en la cultura participativa de los blogs y las redes sociales. Las tareas necesarias para llevar a cabo con exito este modelo de edicion muestran ademas que el investigador-editor de literatura cumpliria dos papeles importantes en la elaboracion de ediciones digitales accesibles a los lectores: una como gestor de contenidos y otra como gestor de una comunidad lectora. Con este modelo propongo experimentar y repensar la manera en que difundimos la literatura de origen impreso de los autores sobre los que investigamos, incluyendo otras formas participativas de implicar a una audiencia lectora convertida ahora en comunidad lectora digital.
Timing-controlled fully programmable analogue signal processors using switched continuous-time filters

Analog signal processors based on continuous-time emulation of sampled-data networks are presented. In these processors, continuous-time signal delay is realized using the phase shift of fixed-frequency, fixed-Q, continuous-time low-pass filters (LPFs), and analog multiplication is accomplished through signal switching using digitally programmable duty cycles. Each coefficient of the processor transfer function is dependently programmable, without requiring selectable capacitor (or resistor) arrays. Experiments verify that this method can be used to construct analog processors with arbitrarily programmable frequency responses. The results presented here are complementary to other results presented earlier by the authors, using sample-data delays. >
Dimerization of native Limulus polyphemus hemocyanin in the presence of calcium ions and sucrose

Abstract In the presence of both sucrose and millimolar concentrations of calcium, native Limulus polyphemus hemocyanin, having a sedimentation coefficient of ~ 60S, forms a dimer with a sedimentation coefficient of ~ 90S. Dimer formation was observed by sucrose gradient ultracentrifugation and gel filtration. It occurs at pH 7.0 but not at pH 8.5 or 6.0, and it is dependent on the calcium concentration. Treatment with EDTA to remove calcium reverses the dimerization process. The effect of sucrose may be due to its known preferential exclusion from the vicinity of proteins [15]. Such preferential exclusion would favor the formation of dimers if the excluded volume of the protein were to decrease on dimerization. Formation of dimer is accompanied by the binding of calcium to hemocyanin, as determined by analysis of gradient fractions by atomic absorption spectroscopy. In addition, stoichiometric amounts of europium (III), known to occupy the calcium binding sites of hemocyanin, also promotes dimer formation. Dimer formation is not induced by 100 mM sodium chloride. The observation of a 90S form of Limulus hemocyanin indicates that there is nothing inherent in the structure of the 60S molecule that prevents further aggregation.
ESL and Multimedia: A Study of the Dynamics of Paired Student Discourse.

Abstract This study examines the interactions of pairs of language students working with multimedia. Six pairs of students of English as a second language were videotaped while working with the instructional system. Transcripts are coded by type and target of participant utterances. A framework for analyzing the interactional dynamic incorporates the ways in which the configuration is likely to shape exchanges given a number of constraints likely to affect conversation. Patterns of discourse on the part of paired subjects were first analyzed within this framework and effects of the identified contraints were observed in the data. Non-native speaker discourse was then compared to native speaker discourse with the identical computer-centered task. Implications are drawn from both the analysis of discourse patterns in light of the configuration constraints, and from discourse elements that occur in the native speaker trial but not in non-native sessions. Discussion centers on how configuration constraints and the unique character of language use of non-native speakers become relevant for teachers and software designers who wish to pair language learners at the computer.
SHARPNESS IN RATES OF CONVERGENCE FOR THE SYMMETRIC LANCZOS METHOD

The Lanczos method is often used to solve a large and sparse symmetric matrix eigenvalue problem. There is a well-established convergence theory that produces bounds to predict the rates of convergence good for a few extreme eigenpairs. These bounds suggest at least linear convergence in terms of the number of Lanczos steps, assuming there are gaps between individual eigenvalues. In practice, often superlinear convergence is observed. The question is "do the existing bounds tell the correct convergence rate in general?". An affirmative answer is given here for the two extreme eigenvalues by examples whose Lanczos approximations have errors comparable to the error bounds for all Lanczos steps.
Learner Interests, Achievement, and Continuing Motivation in Instruction.

Learners often feel that instruction lacks personal relevance. Designing instructional materials that account for learners’ interests may be one means of improving motivation in instruction. High school seniors (N=72) participated in an experimental study that investigated the motivational effects of incorporating their reported interests into instruction. Results showed that significantly more learners were willing to return to a task that used their interests (F=5.76, p<.02). Using interests was valuable for both high and low achievers. Interests are discussed.
Reduction of tracking offset in split-type pickup head of a magneto-optical disk drive

In the optical system of a split type magneto-optical disk drive, the most serious problem is that optical axis tilt and position shift of the moving part could induce large tracking offset. In this research, a mask is used to confine the beam reflected from the disk, such that focus and tracking error signal can be modified. In this way, tracking error signal drift caused by the actuator, while track following, can be decreased. In addition, the DC tracking offset of the moving part, while moving along the guide rod, can be reduced. Crosstalk between tracking and focus signal also can be lowered. In this paper, the optical system simulated by ray tracing and the design of the mask are studied. The test results of the system show that the mask can successfully decrease the tracking offset caused by optical axis tilt and position shift of the moving part.© (1992) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Large scale remote sensing for environmental monitoring of infrastructure

Recent developments in wireless sensor technology afford the opportunity to rapidly and easily deploy large-scale, low-cost, and low-power sensor networks across relatively sizeable environmental regions. Furthermore, the advancement of increasingly smaller and less expensive wireless hardware is further complemented by the rapid development of open-source software components. These software protocols allow for interfacing with the hardware to program and configure the onboard processing and communication settings. In general, a wireless sensor network topology consists of an array of microprocessor boards, referred to as motes, which can engage in two-way communication among each other as well as with a base station that relays the mote data to a host computer. The information can then be either logged and displayed on the local host or directed to an http server for network monitoring remote from the site. A number of wireless sensor products are available that offer off-the-shelf network hardware as well as sensor solutions for environmental monitoring that are compatible with the TinyOS open-source software platform. This paper presents an introduction to wireless sensing and to the use of external antennas for increasing the antenna radiation intensity and shaping signal directivity for monitoring applications requiring larger mote-to-mote communication distances.
Occupational stress and the risk of alcohol abuse and dependence

Using prospective data, we examined the relationship between occupational stress and risk for alcohol disorders. Consistent with the Demand/Control model for psychosocial work environments, we hypothesized that individuals working in high-strain occupations (jobs with high demands and low control) would be at increased risk for alcohol abuse-dependence relative to those in low-strain occupations (jobs with low demands and high control). We classified high occupational strain into two categories: (1) jobs with high psychological demands and low control, and (2) those with high physical demands and low control. A total of 18,571 study subjects were selected in 1980-1984 by taking probability samples of adult household residents at five sites of the Epidemiologic Catchment Area Program. At baseline, participants completed standardized interviews that measured sociodemographic variables and assessed whether they had met diagnostic criteria for currently or formerly active alcohol abuse-dependence syndromes. The interviews were readministered 1 year later to identify cases among the participants. Subjects were sorted into risk sets by age and residence census tract, and persons with a previous history of alcohol abuse or dependence, as well as those who were over 64 years or had no history of full-time employment, were excluded. Among the 507 participants included in the risk sets, there were 126 incident cases of alcohol abuse-dependence and 381 age and residence-matched noncases.(ABSTRACT TRUNCATED AT 250 WORDS)
A Guided Inquiry Liquid/Liquid Extractions Laboratory for Introductory Organic Chemistry

A guided inquiry laboratory experiment for teaching liquid/liquid extractions to first semester undergraduate organic chemistry students is described. This laboratory is particularly useful for introductory students as the analytes that are separated are highly colored dye molecules. This allows students to track into which phase each analyte partitions and allows them to determine if they have successfully separated a mixture of two dyes. During the first part of this experiment, students determine how the partitioning of the various analytes changes as a function of the pH of the aqueous layer. They use these data to determine appropriate solvents for separating mixtures of dyes. After students have learned about the theory and practice of liquid/liquid extractions using dyes, they then separate and identify an unknown simulated cutting agent from a simulated drug. This experiment provides students with a better understanding of the theory and practice of liquid/liquid extractions, and introduces them t...
Spatial and Annual Variations in the Diurnal Cycle of Large-Scale Tropical Convective Cloudiness and Precipitation

Abstract Three years of three-hourly infrared satellite data from the American geostationary satellites were used to determine the large-scale spatial and temporal variations in the diurnal cycle of tropical convective precipitation. The region examined extended from 50°N to 50°S, 175°E to 25°W. The satellite data were related to convection through the fractional coverage of 2.5° subareas by clouds colder than several threshold temperatures. Seasonal maps showing mean fractional coverage, total diurnal variance in cold clouds, as well as variance associated with the first and second harmonic, respectively, present the results. Seasonal maps showing vectors of the amplitude and phase of the first harmonic are also shown. In general, our results agreed with previous studies. The mean positions and annual variations of the maxima and minima in tropical convection were accurately depicted. The diurnal cycle over the tropical continents and the other continents during summer was much larger than that over the ...
Adsorption of polyvinylalcohol onto Fuller's earth surfaces

The adsorption of polyvinyl alcohol (PVA) onto Fuller's earth surfaces has been studied at fixed pH (4.8) and ionic strength of the medium. The adsorption isotherm obtained resembles with LIII type of isotherm, which indicates that multilayer formation of polymer chains begins after a certain time period when the monolayer formation is complete. The study of concentration effect and kinetics of adsorption process enabled in evaluating various adsorption and kinetic parameters such as the adsorption coefficient, modified Freundlich adsorption isotherm constants, distribution coefficient and rate constants for adsorption and desorption. A plausible mechanism of adsorption process was suggested according to which the adsorption was predominantly due to the formation of hydrogen bonds between the OH groups of PVA and aluminols, silanols and carboxylate ions of the organic matter of the Fuller's earth. The proposed mechanism was further confirmed by the IR spectral analysis of native and PVA-adsorbed clay. The adsorption was appreciably affected by the pH, presence of salts, organic solvents, solid to liquid ratio and temperature of the adsorption medium. The study of temperature effect was quantified by calculating various thermodynamic parameters such as Gibb's free energy, enthalpy and entropy. The results obtained in the study helped in formulating a mechanism of interaction between PVA and Fuller's earth surfaces.
Simplified Radiocarbon Analysis Procedure for Measuring the Renewable Diesel Concentration in Diesel Fuel Blends

A simplified analytical approach for determining the renewable diesel content of diesel fuel blends using radiocarbon (14C) analyses in a liquid scintillation counter (LSC) was investigated. Unlike more conventional procedures, the fuels were mixed directly with a fluor and then analyzed in an LSC without further processing. The factory-installed quench curve adequately corrected for variable quench levels in the samples. When using a counting time of 180 min on samples containing 2–20% renewable diesel in fuel blends with relatively low quench levels, mean results from triplicate analyses were accurate to within 0.4% (absolute) and the standard deviations were generally 0.4% (absolute) or less. The accuracy and precision of the analyses were comparable to those observed for AMS and benzene synthesis analyses on the samples. For similar analyses on renewable diesel blends with relatively high quench levels, results were accurate to within 0.8% (absolute) with standard deviations of 0.8% or less when using a counting time of 180 min. The precision was improved significantly by increasing the counting time to 360 min for those samples. Excluding the conventional corrections for isotopic fractionation did not have a significant impact on the accuracy of the results for renewable diesel concentrations of 20% or less.
Topology of ambiguity

Abstract Perceptual ambiguity has recently been used in the investigation of neural correlates of consciousness. We describe a topological phenomenon that may often render complex stimuli ambiguous. Stimuli that are close to a set, A , of perfectly ambiguous stimuli will be difficult to interpret. The probability that a stimulus will be close to A depends on the dimension of A . A topological method we describe can sometimes be used to compute lower bounds for that dimension. Examples where this works and does not work are given.
Chaotic Opto-Mechanical Quivering of Micron-Scaled On-chip Resonators Excited by Radiation Pressure

Opto-mechanical vibration of an on-chip oscillator is experimentally excited by radiation-pressure nonlinearity to a regime where oscillation is chaotic. Period-doubling and broad power spectra are measured in spherical- and toroidal-resonators.
The early universe

Abstract The early Universe, at times prior to recombination 10 5.5 years after the Big Bang, can not be studied by looking at individual objects. However, there are several fossils from this epoch that can be studied. These include the abundances of light elements, and especially the Cosmic Microwave Background Radiation (CMBR). Several space missions ( Copernicus, IUE ), COBE, HST ) have provided information about this era, and planned missions such as the Microwave Anisotropy Probe ( MAP ) and the PLANCK Surveyor will add to our knowledge. The last time when photon creation and destruction rates were fast enough to guarantee a blackbody spectrum was only a month after the Big Bang, so the lack of distortions in the spectrum of the CMBR puts limits on any processes that would add energy to the radiation field at times later than a month. The nearly perfect isotropy of the CMBR shows that the entire observable Universe had to be in causal contact prior to recombination — and this is evidence for inflation. The low amplitude anisotropies of the CMBR that do exist show “equal power on all scales” for large angular scales — more evidence for inflation — and also seem to show a preferred scale near 1°, which corresponds to acoustic oscillations in the baryon-photon fluid. Detailed studies of these acoustic oscillations by MAP and PLANCK will determine the initial conditions for the process of gravitational collapse that has produced the structures seen in the later Universe.
Visual evoked potentials in Leber's hereditary optic neuropathy

Pattern-reversal visual evoked potentials (VEPs) were measured serially in two brothers with Leber's hereditary optic neuropathy during the active phase of the disease. VEP latency and configuration were normal prior to the onset of visual symptoms. The earliest abnormalities consisted of either prolongation of VEP latency or unusual VEP morphology characterized by a double positive peak. As visual acuity declined progressively over a period of months, there was a parallel progressive prolongation of VEP latency accompanied by less consistent diminution of VEP amplitude. In two eyes, VEP ultimately could no longer be measured. VEP latency was normal in most of the asymptomatic family members, including the maternal presumptive carrier. These findings suggest that VEP measurements do not distinguish the presymptomatic or carrier states but do permit quantitative assessment of the activity and progression of the disease.
The NASA Space Environments and Effects Program (SEE): Over a Decade of Useful Products for Spacecraft Designers and Operators

SEE program management originated at LaRC in the early 1990's but was transferred to MSFC in FY 1995 and has remained at Marshall since that time, SEE uses 5 technical working groups and NRA's (three since 1994) to achieve its technical objectives. The SEE vision is to develop and maintain a preeminent program in SPACE ENVIRONMENTS AND EFFECTS which provides a coordinated national focus for innovative technology development to support design, development, and operation of spacecraft systems that will accommodate or mitigate effects due to the presence of the space environment. In working toward that goal, SEE has produced, through the years, over 30 major Space Environments and Effects Models and Databases, over 75 major Space Environments and Effects Publications, a website that has had over 112,000 hits since its inception (http://see.msfc.nasa.gov/), distribution of physical products that amounts to over a total of over 260 product deliveries, sponsorship of the last four international Spacecraft Charging Technology Conferences (the major subject matter conference in the world), and sponsorship of numerous technical standards and guidelines in the Space Environments area. Among the recent popular SEE products are the Electric Propulsion Interactions Code (EPIC), the NASA/Air Force Spacecraft Charging Analysis Program (NASCAP-2K), the Interactive Spacecraft Charging Handbook, the Cosmic Ray Effects on Microelectronics Code (CREME 96), the Spacecraft Contamination and Materials Outgassing Effects Knowledge base (SCMOEK), and the Lunar E-Library.
Automatic Extraction of Filaments in Hα Solar Images

This paper presents a new method which allows for the automatic extraction and tracking of the evolution of filaments in solar images. Series of Hα full-disk images are taken in regular time intervals to observe the changes of the solar disk features. In each picture, the solar chromosphere filaments are identified for further evolution examination. Two alternative preprocessing techniques converting grayscale images into black-and-white pictures with enhanced chromosphere granularity are examined: local thresholding based on median values and global thresholding with brightness and area normalization. The next step employs morphological closing operations with multi-directional linear structuring elements to extract elongated shapes in the image. After logical intersection of directional filtering results, remaining noise is removed from the final outcome using morphological dilation and erosion with a circular structuring element. Experimental results show that the developed technique can achieve excellent results in detecting large filaments and good detection rates for small filaments.
Mining motion patterns using color motion map clustering

Automatically extracting previously unknown behavior patterns from videos that track animals with various physical conditions can accelerate our understanding of animal behaviors and their influential factors, resulting in major medical and economic benefits. Unfortunately, extracting behavior patterns from videos recordings remains as a very challenging task due to their extensive duration and the unstructured natures. This task is further complicated in a completely darken animal cage with inconsistent infrared lighting, moving reflections, or other cage debris such as the cage bedding. In this research, we propose a new motion model that enables us to measure the similarities among different animal movements in high precision so a clustering method can correctly separate recurring movements from infrequent random movements. More specifically, our model first transforms the spatial and temporal features of animal movements into a sequence of color images, referred to as color motion maps (CMMs). The task of mining recurring behavior patterns is then reduced to clustering similar color images in a database. We will use a real infrared video to demonstrate the capability of our model in capturing distinguished but brief animal movements that are embedded within a sequence of other animal movements.
Hydrothermal stability of β-Cs2U2O7 and SrZrO3 in fluids

Abstract The stability of β-Cs 2 U 2 O 7 and SrZrO 3 , two possible phases of spent fuel elements, in hydrothermal fluids was investigated. β-Cs 2 U 2 O 7 was unstable under hydrothermal conditions of 100, 200 and 300°C/300 bars releasing substantial amounts of its Cs in deionized water and all of its Cs in a bittern (high-Mg and-Ca) brine. SrZrO 3 was found to be quite stable in deionized water but not in a bittern brine. For example, Sr released into solution decreased from 3.9 to 2.8% with an increase in temperature from 100 to 300°C probably because of better crystallization of SrZrO 3 at higher temperatures. In bittern brine, 23.3, 94.9 and 100% of Sr was released into solution at 100, 200 and 300°C respectively as a result of acidic conditions generated by the hydrolysis of MgCl 2 and formation of brucite. These results suggest that bittern brine which may be encountered in a salt repository is highly corrosive and may release all the Cs and Sr into solution under hydrothermal conditions if the containment were breached. The use of tailor-made overpacks or backfill barriers of highly stable and sorptive materials is essential especially in a salt repository in order to minimize the threat of highly hazardous Cs and Sr radionuclides finding their way into ground waters.
Human space exploration and human spaceflight: Latency and the cognitive scale of the universe

The role of telerobotics in space exploration as placing human cognition on other worlds is limited almost entirely by the speed of light, and the consequent communications latency that results from large distances. This latency is the time delay between the human brain at one end, and the telerobotic effector and sensor at the other end. While telerobotics and virtual presence is a technology that is rapidly becoming more sophisticated, with strong commercial interest on the Earth, this time delay, along with the neurological timescale of a human being, quantitatively defines the cognitive horizon for any locale in space. That is, how distant can an operator be from a robot and not be significantly impacted by latency? We explore that cognitive timescale of the universe, and consider the implications for telerobotics, human space flight, and participation by larger numbers of people in space exploration. We conclude that, with advanced telepresence, sophisticated robots could be operated with high cognition throughout a lunar hemisphere by astronauts within a station at an Earth-Moon Ll or L2 venue. Likewise, complex telerobotic servicing of satellites in geosynchronous orbit can be carried out from suitable terrestrial stations.
Elevated Global SUMOylation in Ubc9 Transgenic Mice Protects Their Brains against Focal Cerebral Ischemic Damage

We have previously shown that a massive increase in global SUMOylation occurs during torpor in ground squirrels, and that overexpression of Ubc9 and/or SUMO-1 in cell lines and cortical neurons protects against oxygen and glucose deprivation. To examine whether increased global SUMOylation protects against ischemic brain damage, we have generated transgenic mice in which Ubc9 is expressed strongly in all tissues under the chicken β-actin promoter. Ubc9 expression levels in 10 founder lines ranged from 2 to 30 times the endogenous level, and lines that expressed Ubc9 at modestly increased levels showed robust resistance to brain ischemia compared to wild type mice. The infarction size was inversely correlated with the Ubc9 expression levels for up to five times the endogenous level. Although further increases showed no additional benefit, the Ubc9 expression level was highly correlated with global SUMO-1 conjugation levels (and SUMO-2,3 levels to a lesser extent) up to a five-fold Ubc9 increase. Most importantly, there were striking reciprocal relationships between SUMO-1 (and SUMO-2,3) conjugation levels and cerebral infarction volumes among all tested animals, suggesting that the limit in cytoprotection by global SUMOylation remains undefined. These results support efforts to further augment global protein SUMOylation in brain ischemia.
College-Based Teacher Education versus State-Sponsored Alternative Programs.

The number and variety of alternative teacher certification programs have grown rapidly in recent years. In general, alternative certification programs are state sponsored and designed to attract people with college degrees and relevant professional experience but without formal teacher preparation. The alternative program examined in this study is a state-sponsored, on-the-job training program
Economics as Separate and Inexact

The Inexact and Separate Science of Economics (ISSE) offers an overview of standard microeconomics and general equilibrium theory. These are not the whole of orthodox economics, and orthodox economics is not the whole of economics. But orthodox economics dominates the profession, and the theoretical core of microeconomics and general equilibrium theory – what I called ‘equilibrium theory’ – is central to most orthodox economics. Unlike many methodological works, which focus almost exclusively on the empirical problems of equilibrium theory and its applications, ISSE is also concerned with the structure, strategy and heuristics of equilibrium theorizing, and it attempts to link questions about theory appraisal to questions about structure and strategy. It is addressed both to philosophers interested in epistemological questions posed by the social sciences and to economists interested in reflecting on and improving their discipline. Its inspiration lies in the work of John Stuart Mill.
The synovial cadherin (cadherin-11) promotes intercellular motility.

Cadherin-11 is a homophilic adhesion molecule that is expressed on fibroblast-like synoviocytes. Cadherins mediate tissue morphogenesis and architecture. Cadherin cell adhesion contacts are actively remodeled and impact cell movement and migration over other cells. To determine the molecular mechanisms that contribute to cadherin-11-dependent cell migration, we generated cadherin-11 mutants. We found that expression of a mutant cadherin-11 lacking the cytoplasmic juxtamembrane domain (JMD) diminished the turnover of α-catenin at adherens junctions as measured by fluorescence recovery after photobleaching. This resulted in markedly diminished cell intercalation into monolayers reflecting reduced cadherin-11-dependent cell motility on other cells. Furthermore, the actin cytoskeleton in cadherin-11 ΔJMD cells revealed a more extensive cortical F-actin ring that correlated with significantly higher levels of activated Rac1. Together, these studies implicate the cadherin-11 cytoplasmic JMD as a regulator of intercellular motility and cellular rearrangement in multicellular clusters and provide insight into a critical pathway that determines the behavior of fibroblast-like synoviocytes in arthritis, especially rheumatoid arthritis.
Particle velocity near vertical boundaries — A source of uncertainty in two-fluid models

Abstract One of the most restricting uncertainties in the use of the two-fluid models in multiphase computations comes from the solid phase boundary conditions. Typically, the fluid boundary condition at a solid wall is the so called no-slip condition, which has become the cornerstone of single-phase fluid dynamics. By analogy, similar no-slip conditions or variations of them, such as partial slip, are also applied as the boundary conditions of the solid phase (or phases) at impermeable walls in two-fluid model computations. However, and given that the solid phase is subject to the gravitational force, there is not a physical reason as to why the no-slip condition should apply to fine or coarse particles and there are no detailed experiments or simulations that support such a hypothesis. We have undertaken a study, to determine what is the behavior of particles near solid, impermeable walls and what are the velocities of the particles at the plane where their boundary conditions are prescribed (one particle radius far from the wall). This will help prescribe the correct boundary conditions for the solid phase of a multiphase mixture and will remove a cause of uncertainty in particulate modeling. The study is based on Direct Numerical Simulations (DNS) of a dense particulate flow and the results pertain to both dilute and dense mixtures. Since the model of particle–wall interactions/collisions is important in the results, the computations include the parameters of the particle–wall interaction model of DNS. The results show that the solid-phase velocity at a vertical wall is clearly negative, in the direction of gravity, and that the absolute value of the velocity depends primarily on the size of the particles.
Induction of cytochrome P450 1A in the American Eel by model halogenated and non-halogenated aryl hydrocarbon receptor agonists.

Eels (Anguilla sp.) have phylogenetic, life history, and morphological characteristics which distinguish them from many other species that have been examined for cytochrome P450 1A (CYP1A) induction. Members of the family Anguillidae often occur in regions of the coastal environment that are heavily impacted by chemical contamination. Although eels have been suggested to be a useful species for biomonitoring, the sensitivity with which eel CYP1A is induced by aryl hydrocarbon receptor (AHR) agonists is not known. We investigated the dose-dependent induction of hepatic CYP1A in the American eel (Anguilla rostrata). Eels from an uncontaminated site were injected intra-peritoneally with the model AHR agonists s-naphthoflavone (BNF), benzo[a]pyrene (B[a]P) or 3,3',4,4-tetrachlorobiphenyl (TCB) at increasing doses (BNF at 0.1, 1, 10 and 100 mg/kg, B[a]P at 0.1, 1 and 10 mg/kg, and TCB at 0.1, 1, 10 and 20 mg/kg). All three compounds produced dose-dependent induction of CYP1A content and catalytic activity. An estimated ED(50) for induction of liver microsomal EROD activity by TCB was approximately 5 mg/kg, indicating only moderate sensitivity. At comparable doses of 1 and 10 mg/kg (or 3-4 and 30-40 µmol/kg), BNF and B[a]P had 2-3-fold greater effect than TCB in eliciting hepatic CYP1A induction. Injection of radiolabeled B[a]P and TCB resulted in similar dose-dependent concentrations of these compounds in eel liver, and the hepatic inducer concentrations and CYP1A levels were correlated positively. Eels collected from New Bedford Harbor (NBH), a Superfund site highly contaminated by polycyclic aromatic hydrocarbons and polychlorinated biphenyls, had levels of microsomal CYP1A protein and EROD activity that were equivalent to the highest levels induced experimentally. Eels from less contaminated sites had correspondingly less CYP1A expression. The responses to B[a]P or BNF as compared to TCB suggest a lower efficacy and/or potency for CYP1A induction by TCB which could involve differences in the mechanisms of responses to these compounds in eels. However, the moderate sensitivity and the CYP1A induction in NBH eels support suggestions that eels may be useful in monitoring more contaminated regions.
5-Methyltryptophan and darkening of the hair in yellow Ay/a mice.

PREVIOUS experiments have shown that powdered preparations of the skin and hair of yellow (Ay/a) mice oxidize L- (but not D-) tryptophan and also DL-5-hydroxytryptophan with the production of yellow solutions1,2. To obtain further evidence on the question of whether tryptophan, or a derivative, might be implicated in the production of yellow pigment in the hairs of this strain of mice, in vivo experiments were carried out using an antimetabolite of tryptophan3. Starting at 3–4 days of age, daily subcutaneous injections of DL-5-methyltryptophan were made in these mice for a period of 7–10 days. This is a period of vigorous pigment production. (Mice were obtained from the R. B. Jackson Memorial Laboratories, Bar Harbor, Maine. DL-5-methyl-tryptophan was a product of Sigma Chemical Co., St. Louis, Mo.)
SU‐GG‐I‐99: Validation and Comparison of 3D Image Registration Approaches for Adaptive IMRT in Head‐And‐Neck Cancer

Purpose: 3D image registration is a key component in image‐guided adaptive radiotherapy. It is imperative that the accuracy of a registration method is assured prior to clinical implementation. However, registration validation is scarcely covered in the literature. In this work, we validated and compared seven registration methods for CT/MRI and MRI/MRI fusion in adaptive radiotherapytreatment planning of head‐and‐neck tumors.Method and Materials: A planning CTimage and an MRIimage were acquired before the treatment and seven weekly MRIs acquired during an IMRT head‐and neck cancer treatment. Seven methods including intensity‐based, surface‐based, landmark‐based, manual, and non‐rigid registrations were applied to align 2 pairs of CT/MRI, and 8 pairs of MRI/MRI datasets. For each registration, eight anatomic landmarks were identified in each image. The distance between the transformed landmark position and the manually determined position was calculated. The registration accuracy was estimated by the mean distance. Results: The mean distances between CT/MRI and MRI/MRI landmarks were approximately 2.0 mm. For CT/MRI registration, intensity‐based registration plus manual adjustment performed the best with the smallest registration error of 1.2 mm. Non‐rigid and manual methods both had small errors of 1.5 mm. Surface‐based and landmark‐based methods had larger errors of 3.3 mm and 2.4 mm, respectively. For MRI/MRI registration, non‐rigid methods had the smallest registration error of 1.3 mm. Similarly, surface‐based and landmark‐based methods had larger errors of 2.8 mm and 2.9 mm, respectively. Non‐rigid method and landmark‐based methods had the greatest registration error variances. Conclusion: We qualitatively and quantitatively evaluated seven methods on CT‐MRI and MRI‐MRI registration for head‐and‐neck patient. Careful and quantitative evaluation of the registration accuracy is important for the identification of the optimized registration method, the application of multimodality imaging in treatment planning, and the daily image guidance in treatment delivery.
Ethnocentrism, intercultural communication apprehension, intercultural willingness‐to‐communicate, and intentions to participate in an intercultural dialogue program: Testing a proposed model

This study investigates the relationships between ethnocentrism, intercultural communication apprehension, intercultural willingness‐to‐communicate, and college students' intentions to engage in an intercultural dialogue program. Data collected from a survey of 339 students in a midwestern university were used to test a proposed model. The results show that ethnocentrism and intercultural communication apprehension are related to each other and that intercultural willingness‐to‐communicate is influenced by both ethnocentrism and intercultural communication apprehension. Both ethnocentrism and intercultural willingness‐to‐communicate have a direct influence on students' intentions to engage in an intercultural dialogue program, but intercultural communication apprehension does not directly influence intentions. Implications of these findings are discussed.
Comparison of zero crossing counter to FFT spectrum of ultrasound Doppler

Doppler data were obtained from a normal carotid, popliteal, and radial artery. It was found that the results of a digital zero-crossing counter-mean frequency estimate and the first moment of the FFT (fast-Fourier-transform)-generated spectra were comparable for high signal-to-noise ratio (SNR), as in the case of the carotid arterial waveform. However, the digital zero-crossing with thresholding was a more accurate representation of the expected velocity-vs.-time waveforms in the case of low-SNR Doppler obtained from the popliteal and radial arteries. >
A numerical study of high-pressure droplet vaporization

Abstract The evaporation of single, spherical fuel droplets in a high-pressure, high-temperature environment has been studied numerically. The model is fully transient in both the liquid and the vapor phases. Transport properties are functions of temperature, pressure, and composition, and vary throughout the liquid droplet and the vapor boundary layer. Equilibrium at the liquid-vapor interface is calculated using the Peng-Robinson equation of state, and accounts for diffusion of the gas into the liquid droplet. The Peng-Robinson equation of state is also used to calculate the enthalpy of vaporization of the fuel species as well as the liquid and vapor mixture densities. The proposed model is compared with data obtained for a variety of liquids. The comparisons include the predictions of the critical mixing state, droplet vaporization rate, and droplet temperature. Transient effects in both the liquid and vapor phases are found to have a large effect on the droplet heatup and vaporization process. At very high temperature and pressure conditions the droplets were found to reach their thermodynamic critical mixing point in a totally transient process. Coupled diffusion processes were studied and found to be an important factor in high-pressure droplet vaporization. Anomalies in the transport properties of a fluid near its critical mixing point were studied and found to be insignificant in droplet vaporization under conditions similar to those in a diesel engine.