cssi/SciSciGPT-SciSciNet huggingface dataset:
Traumatic corneal abrasions after excimer laser keratectomy.

Inquiries to Michael P. Vrabec, M.D., University Health Center, 1 S. Prospect sr: Burlington, VT 05401. The excimer laser helps in the treatment of corneal surface disease as well as myopic and astigmatic refractive errors. Both phototherapeutic and photorefractive studies have reported successful use of the excimer laser.P One concern with the excimer laser is that removal of the epithelium before treatment could result in future healing problems between the stroma, Bowman's membrane, and the epithelium, especially if the epithelium is removed because of trauma at a future time. Hypertrophic stromal scarring could result if the epithelium is later removed." We studied two patients with traumatic corneal abrasions after excimer laser therapy, which did not result in any serious sequelae such as stromal scarring, recurrent erosions, or a change in the patients' refractive errors.
Aerosols of high chlorine concentration transported into central and eastern United States

During 18–21 December 1980 a remarkable change occurred in the composition of the aerosol over a broad region of the central and eastern United States: the weight per cent of chlorine present in small aerosol particles increased by nearly two orders of magnitude. We report here an analysis of the aerosol composition and meteorology during the period of change which suggests that this increase was the result not of a pollution episode, but of a massive intrusion of very clean maritime air from the northern Pacific into a region extending at least from Wisconsin southwards to Kansas and Missouri and eastwards to Ohio.
Cognitive Capacity Usage in Responding to Test Items

Procedures for validating the complexity level of test items include empirical examinations of item characteristics and subjective judgments of expert raters. These methods have yielded mixed and inconsistent results. This study employs a technique derived from cognitive psychology research in the examination of levels of item complexity. Using a microcomputer to administer test items, response time to a secondary task was used as an index of the level of item complexity. A series of three studies are reported that (1) employ the technique on items of marked discrepancy in complexity level and (2) contrast the sensitivity of the technique to more traditional analyses of level of item complexity. The results suggest that the technique has promise as a mechanism for validating or establishing level of item complexity.
Targeting protein–protein interactions in hematologic malignancies: still a challenge or a great opportunity for future therapies?

Over the past several years, there has been an increasing research effort focused on inhibition of protein-protein interactions (PPIs) to develop novel therapeutic approaches for cancer, including hematologic malignancies. These efforts have led to development of small molecule inhibitors of PPIs, some of which already advanced to the stage of clinical trials while others are at different stages of pre-clinical optimization, emphasizing PPIs as an emerging and attractive class of drug targets. Here, we review several examples of recently developed inhibitors of protein-protein interactions highly relevant to hematologic cancers. We address the existing skepticism about feasibility of targeting PPIs and emphasize potential therapeutic benefit from blocking PPIs in hematologic malignancies. We then use these examples to discuss the approaches for successful identification of PPI inhibitors and provide analysis of the protein-protein interfaces, with the goal to address ‘druggability’ of new PPIs relevant to hematology. We discuss lessons learned to improve the success of targeting new protein-protein interactions and evaluate prospects and limits of the research in this field. We conclude that not all PPIs are equally tractable for blocking by small molecules, and detailed analysis of PPI interfaces is critical for selection of those with the highest chance of success. Together, our analysis uncovers patterns that should help to advance drug discovery in hematologic malignancies by successful targeting of new protein-protein interactions.
The mullins effect in uniaxial extension and its influence on the transverse vibration of a rubber string

This paper presents a study of the stress softening effect encountered in uniaxial extension and explores its effect on the small amplitude transverse vibration of a stretched rubber cord. An idealization of the uniaxial stressstrain behavior of a stress softening material is presented, the importance of the deformation history is emphasized, and parameters are introduced to track the deformation history. An extended investigation of a model proposed by Mullins and Tobin to quantify stress softening by introduction of a strain amplification factor is then presented. A major result derived from this model is shown to be consistent with results reported by others. The uniaxial stress softening theory is used to describe the transverse vibration behavior of a rubber string subjected to repeated stretching. This appears to be the first application of the softening model of Mullins and Tobin to a dynamical problem. Analytical results are compared with uniaxial stress-strain and transverse vibration experiments performed with buna-n, neoprene, and silicone rubber cords. Both types of experiments provide a simple and novel method to evaluate the predictive success of our uniaxial theory without the need for a specific constitutive model. The pseudoelastic response found in biological tissues is discussed in light of results obtained in the transverse vibration experiments.
Endothelin-1 Upregulates MCAM in Melanocytes

Melanoma cell adhesion molecule (MCAM) is a cell-surface adhesion molecule expressed on over 70% of metastatic melanoma cells but not expressed in normal melanocytes invivo. Protein levels of MCAM correlate with aggressive invasive behavior of melanoma cells in vitro and invivo. Here we demonstrate that endothelin-1 (ET-1) upregulates MCAM protein in primary human melanocytes. MCAM upregulation by ET-1 occurs irrespective of degree of melanocyte pigmentation and is dose-responsive. The drug BQ788 is an endothelin-B (ETB) receptor antagonist and inhibits upregulation of MCAM by ET-1. In addition, endothelin-3 (ET-3) and N-succinyl-[Glu9, Ala11, 15]-ET-1-1620, both selective ETB agonists, are potent upregulators of MCAM. These demonstrate a critical role for the ETB receptor in the upregulation of MCAM by ET-1 and related isoforms. MCAM mRNA abundance is also increased by ET-1 stimulation, thus the mechanism of MCAM protein upregulation may occur at the level of transcription. Our previous studies have demonstrated that ET-1 downregulates E-cadherin in melanocytes and melanoma cells. Since E-cadherin is a melanoma invasion suppressor, and MCAM is a melanoma invasion promoter, ET-1 may promote melanoma invasion and metastasis through the regulation of adhesion molecule expression.
Alleviating energy poverty for the world's poor

Abstract Improving energy services for poor households in developing countries remains one of the most pressing challenges facing the development community. The dependence of these households on traditional forms of energy leads to significant health impacts as well as other major disbenefits, yet there has been little progress in meeting this challenge. This viewpoint argues for an ‘energy-poverty alleviation’ fund to help provide modern energy services to these households. It also proposes an approach through which to create such a fund, namely by introducing an incremental levy on petroleum. Notably, this scheme does not need a global agreement since a levy could be introduced by major oil-exporting countries. The implementation of this mechanism would result in a climate-friendly outcome (even before taking into account the elimination of products of incomplete combustion resulting from the traditional household use of biomass-based fuels) while providing immense socio-economic benefits to the world's poor. Such an approach would allow significant progress on the sustainable development front while reducing global greenhouse gas emissions, and therefore is very much consistent with the United Nations Framework Convention on Climate Change.
Media banks: entertainment and the Internet

There are two emerging models for delivering high-density, synchronized audiovisual presentations: video-on-demand and the Internet. The first is based on long-lived connections and guaranteed timeliness; the second assumes short spurts of low-bandwidth data on demand. We present the design for a Media Bank that intermediates between them. It provides on-demand access to media elements that are assembled on-the-fly by the recipient to reproduce synchronized audiovisual presentations. The Media Bank uses a fully distributed architecture that assumes a community of viewers. Any member citizen can request or deliver sound, picture, descriptive annotations, or programs to control assembly. Data are redundantly stored in small segments and are cataloged by content and format to facilitate personalized and interactive retrieval.
Transformations of nonlinear dynamical systems to jerky motion and its application to minimal chaotic flows

Third-order explicit autonomous differential equations in one scalar variable or, mechanically interpreted, jerky dynamics constitute an interesting subclass of dynamical systems that can exhibit many major features of regular and irregular or chaotic dynamical behavior. In this paper, we investigate the circumstances under which three dimensional autonomous dynamical systems possess at least one equivalent jerky dynamics. In particular, we determine a wide class of three-dimensional vector fields with polynomial and non-polynomial nonlinearities that possess this property. Taking advantage of this general result, we focus on the jerky dynamics of Sprott's minimal chaotic dynamical systems and R\"ossler's toroidal chaos model. Based on the interrelation between the jerky dynamics of these models, we classify them according to their increasing polynomial complexity. Finally, we also provide a simple criterion that excludes chaotic dynamics for some classes of jerky dynamics and, therefore, also for some classes of three-dimensional dynamical systems.
Environmental control of Th17 differentiation

Th17 cells participate in the control of extracellular bacteria and fungi, but dysregulated Th17 cell activity can result in immunopathology. Thus, the generation and the activity of Th17 cells should be tightly regulated, and simultaneously it should be able to respond to the challenges presented by a changing environment. In this viewpoint, we discuss some of the mechanisms by which microbes, dietary components and environmental toxins influence the Th17 response.
Fluorinated phosphazene co-solvents for improved thermal and safety performance in lithium-ion battery electrolytes

The safety of lithium-ion batteries is coming under increased scrutiny as they are being adopted for large format applications especially in the vehicle transportation industry and for grid-scale energy storage. The primary short-comings of lithium-ion batteries are the flammability of the liquid electrolyte and sensitivity to high voltage and elevated temperatures. We have synthesized a series of non-flammable fluorinated phosphazene liquids and blended them with conventional carbonate solvents. While the use of these phosphazenes as standalone electrolytes is highly desirable, they simply do not satisfy all of the many requirements that must be met such as high LiPF6 solubility and low viscosity, thus we have used them as additives and co-solvents in blends with typical carbonates. The physical and electrochemical properties of the electrolyte blends were characterized, and then the blends were used to build 2032-type coin cells which were evaluated at constant current cycling rates from C/10 to C/1. We have evaluated the performance of the electrolytes by determining the conductivity, viscosity, flash point, vapor pressure, thermal stability, electrochemical window, cell cycling data, and the ability to form solid electrolyte interphase (SEI) films. This paper presents our results on a series of chemically similar fluorinated cyclic phosphazene trimers, themore » FM series, which has exhibited numerous beneficial effects on battery performance, lifetimes, and safety aspects.« less
Birth weight for gestational age of Mexican American infants born in the United States

Objective: To develop a reference for birth weight for gestational age to identify Mexican American infants born in the United States who are small or large for gestational age. Methods: Reference percentiles were developed for Mexican American and non-Hispanic white births, using national vital statistics from 1992–1994 for Mexican Americans (n = 1,197,916) and 1994 for non-Hispanic whites (n = 2,238,457). Birth weights and gestation from the last menstrual period were taken from birth certificates. Smoothed curves were fit, using unweighted fourth-degree polynomial equations, for the tenth, 50th, and 90th percentiles by gender and parity. Results: Mexican American infants were heavier than non-Hispanic white infants between 30 and 37 weeks’ gestation for all parities and both genders. However, at term there was consistent crossover. Non-Hispanic white infants were heavier at or after 37 through 42 weeks’ gestation, whereas the growth of Mexican American infants appeared to slow. Beginning at 37 weeks, the differences in weights of infants of primiparas increased to more than 100 g by 40 weeks; the differences were only slightly less for infants of multiparas. Conclusion: Given differences in distribution of birth weights for gestational age between Mexican Americans and non-Hispanic whites, the ability to recognize fetal growth restriction (FGR) or excessive growth is questionable. These data provide a reference for Mexican Americans for clinical use and for future studies in identifying infants at risk for FGR or overgrowth. (Obstet Gynecol 1999;93:943–7.)
Understanding correlation : Factors that affect the size of r

ABSTRACT. The authors describe and illustrate 6 factors that affect the size of a Pearson correlation: (a) the amount of variability in the data, (b) differences in the shapes of the 2 distributions, (c) lack of linearity, (d) the presence of 1 or more "outliers," (e) characteristics of the sample, and (f) measurement error. Also discussed are ways to determine whether these factors are likely affecting the correlation, as well as ways to estimate the size of the influence or reduce the influence of each.
The Possible Role of Indoor Radon Reduction Systems in Back-Drafting Residential Combustion Appliances

Abstract A computational sensitivity analysis was conducted to identify the conditions under which residential active soil depressurization (ASD) systems for indoor radon reduction might most likely exacerbate or create back-drafting of natural-draft combustion appliances. Parameters varied included: house size; normalized leakage area; exhaust rate of exhaust appliances other than the ASD system; and the amount of house air exhausted by the ASD system. Even with a reasonably conservative set of assumptions, it is predicted that ASD systems should not exacerbate or create back- drafting in most of the U.S. housing stock. Only at normalized leakage areas lower than 3 to 4 cm2 (@ 4 Pa) per m2 of floor area should ASD contribute to back-drafting, even in small houses at high ASD exhaust rates (compared to a mean of over 10 cm2/m2 determined from data on over 12,000 U.S. houses). But on the other hand, even with a more forgiving set of assumptions, it is predicted that ASD systems could contribute to back-drafting in some fraction of the housing stock – houses tighter than about 1 to 2 cm2/m2– even in large houses at minimal ASD exhaust rates. It is not possible to use parameters such as house size or ASD system flow rate to estimate reliably the risk that an ASD system might contribute to back-drafting in a given house. Spillage/back-draft testing would be needed for essentially all installations.
A note on generalized radial mesh generation for plasma electronic Structure

Abstract Precise electronic structure calculations of ions in plasmas benefit from optimized numerical radial meshes. A new closed form expression for obtaining non-linear parameters for the efficient generation of analytic log-linear radial meshes is presented.
Design and Spacecraft-Integration of RTGs for Solar Probe

Presented at the 41st Congress of the IAF, October 6-12, 1990 in Dresden, FRG. The paper describes the design and analysis of Radioisotope Thermoelectric Generators integrated with JPL's planned Solar Probe spacecraft. The principle purpose of the Solar probe mission is to explore the solar corona by performing in-situ measurements at distances as close as four solar radii or 0.02 AU from the sun. This proximity to the sun imposes some unusual design constraints on the RTG and on its integration with the spacecraft. The results demonstrated that the obstructions result in significant performance penalties for the case of the standard GPHS-RTG design. Finally, the paper describes a simple empirical method for predicting the combined effect of fuel decay and thermoelectric degradation on the RTG's power output, and applies that method to predict the long-term power profile of the obstructed Solar Probe RTGs. The results indicate that the existing GPHS-RTG design, even without modifications can meet the JPL-prescribed EOM power requirement. There is also three copies in the file of an earlier version of this dated 8/3/1990 with the report number of FSC-ESD-217-90-470. The most current one is the IAF version (IAD-90-208) dated October 6-12, 1990.
Positive and negative selection of an antigen receptor on T cells in transgenic mice

The T-cell repertoire found in the periphery is thought to be shaped by two developmental events in the thymus that involve the antigen receptors of T lymphocytes. First, interactions between T cells and major histocompatibility complex (MHC) molecules select a T-cell repertoire skewed towards recognition of antigens in the context of self-MHC molecules. In addition, T cells that react strongly to self-MHC molecules are eliminated by a process called self-tolerance. We have recently described transgenic mice expressing the alpha beta T-cell receptor from the cytotoxic T lymphocyte 2C (ref. 11). The clone 2C was derived from a BALB.B (H-2b) anti-BALB/c (H-2d) mixed lymphocyte culture and is specific for the Ld class I MHC antigen. In transgenic H-2b mice, a large fraction of T cells in the periphery expressed the 2C T-cell receptor. These T cells were predominantly CD4-CD8+ and were able to specifically lyse target cells bearing Ld. We now report that in the periphery of transgenic mice expressing Ld, functional T cells bearing the 2C T-cell receptor were deleted. This elimination of autoreactive T cells appears to take place at or before the CD4+CD8+ stage in thymocyte development. In addition, we report that in H-2s mice, a non-autoreactive target haplotype, large numbers of CD8+ T cells bearing the 2C T-cell receptor were not found, providing strong evidence for the positive selection of the 2C T-cell receptor specificity by H-2b molecules.
A comparative study of 14 cases of familial and nonfamilial pheochromocytomas

A comparison is made between epidemiological features found in a group of 14 patients with familial and nonfamilial pheochromocytomas at M. D. Anderson Hospital and Tumor Institute. The Sipple syndrome (familial) group comprised eitht patients from three different families, and the nonfamilial group consisted of six nonrelated patients. The main differences were noted in the age of onset, sex ratio, bilaterality, malignant behavior, and occurrence of a second nonendocrine primary tumor. An attempt was made by light microscopy to define features that would indicate malignant behavior. No such features could be delineated. Survival time was unrelated to the presence of pheochromocytoma except in operative and investigative procedures.
Salt-resistant hypertension in mice lacking the guanylyl cyclase-A receptor for atrial natriuretic peptide

Around half of all humans with essential hypertension are resistant to salt (blood pressure does not change by more than 5 mm Hg when salt intake is high), and although various inbred strains of rats display salt-insensitive elevated blood pressure, a gene defect to account for the phenotype has not been described. Atrial natriuretic peptide (ANP) is released from the heart in response to atrial stretch and is thought to mediate its natriuretic and vaso-relaxant effects through the guanylyl cyclase-A receptor (GC-A). Here we report that disruption of the GC-A gene results in chronic elevations of blood pressure in mice on a normal salt diet. Unexpectedly, the blood pressure remains elevated and unchanged in response to either minimal or high salt diets. Aldosterone and ANP concentrations are not affected by the genotype. Therefore, mutations in the GC-A gene could explain some salt-resistant forms of essential hypertension and, coupled with previous work, further suggest that the GC-A signaling pathway dominates at the level of peripheral resistance, where it can operate independently of ANP.
Spontaneous generalized spike-wave discharges in the electrocorticograms of albino rats

Abstract Generalized epileptiform discharges occur spontaneously in the electrocorticograms of some albino laboratory rats. These discharges occur during periods of quiet wakefulness, are composed of 6–10/sec spike-wave complexes, are accompanied by locomotor arrest and often by mild clonic facial movements. The occurrence of these discharges is unrelated to surgical procedures used to create chronic recording preparations. Similar discharges and behavior have been induced in controls by injections of pentylenetetrazol.
Contour Integration and Segmentation with Self-Organized Lateral Connections

Contour integration in low-level vision is believed to occur based on lateral interaction between neurons with similar orientation tuning. How such interactions could arise in the brain has been an open question. Our model suggests that the interactions can be learned through input-driven self-organization, i.e., through the same mechanism that underlies many other developmental and functional phenomena in the visual cortex. The model also shows how synchronized firing mediated by these lateral connections can represent the percept of a contour, resulting in performance similar to that of human contour integration. The model further demonstrates that contour integration performance can differ in different parts of the visual field, depending on what kinds of input distributions they receive during development. The model thus grounds an important perceptual phenomenon onto detailed neural mechanisms so that various structural and functional properties can be measured and predictions can be made to guide future experiments.
Validation of the worry about sexual outcomes scale for use in STI/HIV prevention interventions for adolescent females

This study examined the psychometric properties of a new scale to measure adolescents’ worry regarding outcomes of risky sexual behavior (i.e. sexually transmitted infections, including HIV [STI/HIV], and unintended pregnancy). The 10-item worry about sexual outcomes (WASO) scale, resulting in two subscales STI/HIV worry and pregnancy worry, was administered to a sample of 522 African-American female adolescents ranging in age from 14 to 18, residing in the southeast United States and participating in a sexual risk reduction intervention. The WASO demonstrated internal consistency across multiple administrations and yielded satisfactory construct validity. Worry was found to negatively correlate with sexual communication self-efficacy (with a new male partner and a steady male partner), frequency of sexual communication with male partner, attitudes about condom use and social support; worry was positively correlated with perceived barriers to condom use, condom negotiation, locus of control and depression. Overall, the results indicate that the WASO is a reliable and valid measure of assessing adolescents’ worry about STIs, HIV and pregnancy. The WASO represents a brief self-administered instrument that can be easily integrated into sexual risk reduction assessments and interventions. Future studies employing the WASO might consider testing it with more diverse samples in terms of gender, race/ethnicity, age and sexual orientation.
MPE graphics-scalable X11 graphics in MPI

Parallel programs need the same programming libraries as sequential programs, and in as easy to use a form. In addition, the semantics of parallel graphics operations need to be defined. We describe a parallel graphics library that provides parallel semantics, both independent and collective, that take advantage of the MPI Standard to ensure safety, ease of use, and independence from user programs. For performance, particularly on machines with large numbers of processors, the communication patterns used by the parallel graphics routines need to be under user control. Parallel graphics will generate communication traffic, which needs to be kept isolated from other user messages or library based message passing. Fortunately, the new MPI message passing standard allows isolation of such communication in communication "contexts". We describe an X-based parallel graphics library that relies on MPI for communication. It is an MPI library and is independent of which particular MPI implementation is being used for the underlying communication. >
BIOCHEMICAL ADAPTATIONS IN THE MESOLIMBIC DOPAMINE SYSTEM IN RESPONSE TO HEROIN SELF-ADMINISTRATION

Previous studies have shown that chronic, forced exposure to opiates produces specific biochemical adaptations in the ventral tegmental area (VTA) and nucleus accumbens (NAc). The functional consequences of these adaptations have been hypothesized to contribute to certain motivational aspects of drug addiction. In this study, the possibility that similar adaptations could occur in response to intermittent heroin self-administration was tested by comparing homogenates of VTA and NAc from rats self-administering heroin, rats receiving yoked injections of heroin, and rats receiving yoked injections of saline (controls). Tyrosine hydroxylase (TH) immunoreactivity was increased (31-38%) in the VTA and decreased (11%) in the NAc of heroin-exposed rats relative to controls. Heroin exposure also increased cAMP-dependent protein kinase (PKA) activity in both particulate (19-27%) and soluble (17-20%) fractions of the NAc, and decreased (16-17%) the level of Gi alpha immunoreactivity in this brain region. In contrast, no significant biochemical changes were found in the substantia nigra or caudate-putamen, indicating a selective effect on the mesolimbic dopamine system. Overall, adaptations in the VTA and NAc of heroin-exposed rats were similar to, but generally smaller in magnitude than, adaptations produced by chronic morphine administration. However, in contrast to morphine-treated animals, heroin-exposed animals failed to display overt signs of opiate physical dependence, suggesting that adaptations in motivational systems may occur more readily than adaptations in brain regions associated with physical dependence.
Did Reform of Prudent Trust Investment Laws Change Trust Portfolio Allocation

Abstract This paper investigates the effect of changes in state prudent trust investment laws on asset allocation in noncommercial trusts. The old prudent‐man rule favored “safe” investments and disfavored “speculation” in stock. The new prudent‐investor rule directs trustees to craft an investment portfolio that fits the risk tolerance of the beneficiaries and the purpose of the trust. Using state‐ and institution‐level panel data from 1986–97, we find that after adoption of the new prudent‐investor rule, institutional trustees held about 1.5–4.5 percentage points more stock at the expense of “safe” investments. Our findings explain roughly 10–30 percent of the overall increase in stock holdings in the period studied. The rest of the increase appears to be attributable to stock market appreciation. We conclude that, even though trust fiduciary laws are nominally default rules, institutional trustees are nonetheless sensitive to changes in those rules.
Adding Some TEC-VARIETY: 100+ Activities for Motivating and Retaining Learners Online by Curtis J. Bonk and Elaine Khoo

Adding Some TEC-VARIETY: 100+ Activities for Motivating and Retaining Learners Online presents a collection of tried and tested activities that have been successfully implemented by online and blen...
Service Systems and Service-Dominant Logic: Partners or Distant Cousins?

This article explores potential relationships between service systems (S. Alter, 2008b) and S. L. Vargo and R. F. Lusch's (2004) service-dominant logic (S-D logic). Both approaches explicate fundamental ideas but at different levels of analysis and for different purposes. S-D logic characterizes intersections between marketing and economics, whereas service system frameworks and concepts were developed to help business and information technology professionals understand, analyze, implement, and improve service systems in organizations. The service system lens illuminates many system-related areas to which S-D logic might apply; it ignores other topics concerning markets. Concepts in S-D logic related to customers, services, and economic exchange might enrich service system analysis. Overlaps and synergies might lead to insights into both approaches.
Interpreting Negative Results in an Angle Maximization Problem

The correct interpretation of positive and negative results in a situation involving mathematical modeling poses problems for some students. This article presents a situation in which differential calculus is used with inverse trigonometric tangentfunctions to maximize an angle measure. A negative distance measure ultimately results, thus requiring a reconsideration of assumptions inherent in the initial figure.
Some Observations on the Kinetics of the C∙4 Epimerization of Tetracycline

Abstract The C∙4 epimerization of tetracycline has been shown to follow the kinetics of a first-order reversible reaction. Phosphate and citrate ions increased the rate of C∙4 epimerization. The reaction rate in either 1.00 molar phosphate or 1.00 molar citrate buffer at pH 4.0 and 23° was approximately 70 times the rate observed in distilled water under the same conditions of temperature and pH. An Arrhenius plot indicated that the apparent energy of activation for the C∙4 epimerization of tetracycline at pH 4.0 and 0.10 molar phosphate buffer was approximately 20 kilo-calories/gram-mole. The equilibrium concentration and the rate at which equilibrium was approached were dependent on the pH. Of the five pH levels studied, a maximum C∙4 epimer level of 55 per cent at equilibrium occurred at pH 3.2. Of the five pH levels studied, the rate at which equilibrium was approached was highest at pH 3.2, 4.0, and 5.0.
How important is competition in a species-rich grassland? A two-year removal experiment in a pine savanna

Abstract Although we know that competition sometimes controls the composition of plant communities, we still do not understand its significance in communities having high species richness. We removed an abundant and apparently dominant grass (Andropogon virginicus) in species-rich pine grassland in southeastern louisiana and evaluated the effects on species richness and composition. At 2 sites, moist and dry, we located twenty 1- × 1-m plots with 10 randomly assigned control plots and 10 treatment plots, in which herbicide was applied to individual shoots of A. virginicus over 2 y. Plant cover, species richness, and species composition were recorded 4 times over this period. Repeated measures analyses of variance and Mantel tests were used to evaluate differences between control and removal plots. Although there were more than 90 species of vascular plants that might have responded to the removal of A. virginicus, no significant effect on cover, species richness, species composition, or functional group c...
Arabidopsis Peroxin 16 Coexists at Steady State in Peroxisomes and Endoplasmic Reticulum

Homologs of peroxin 16 genes (PEX16) have been identified only in Yarrowia lipolytica, humans (Homo sapiens), and Arabidopsis (Arabidopsis thaliana). The Arabidopsis gene (AtPEX16), previously reported as the SSE1 gene, codes for a predicted 42-kD membrane peroxin protein (AtPex16p). Lin et al. (Y. Lin, J.E. Cluette-Brown, H.M. Goodman [2004] Plant Physiol 135: 814–827) reported that SSE1/AtPEX16 was essential for endoplasmic reticulum (ER)-dependent oil and protein body biogenesis in peroxisome-deficient maturing seeds and likely also was involved in peroxisomal biogenesis based on localization of stably expressed green fluorescent protein::AtPex16p in peroxisomes of Arabidopsis plants. In this study with Arabidopsis suspension-cultured cells, combined in vivo and in vitro experiments revealed a novel dual organelle localization and corresponding membrane association/topology of endogenous AtPex16p. Immunofluorescence microscopy with antigen affinity-purified IgGs showed an unambiguous, steady-state coexistence of AtPex16p in suspension cell peroxisomes and ER. AtPex16p also was observed in peroxisomes and ER of root and leaf cells. Cell fractionation experiments surprisingly revealed two immunorelated polypeptides, 42 kD (expected) and 52 kD (unexpected), in homogenates and microsome membrane pellets derived from roots, inflorescence, and suspension cells. Suc-gradient purifications confirmed the presence of both 42-kD and 52-kD polypeptides in isolated peroxisomes (isopycnic separation) and in rough ER vesicles (Mg2+ shifted). They were found peripherally associated with peroxisome and ER membranes but not as covalently bound subunits of AtPex16p. Both were mostly on the matrix side of peroxisomal membranes and unexpectedly mostly on the cytosolic side of ER membranes. In summary, AtPex16p is the only authentic plant peroxin homolog known to coexist at steady state within peroxisomes and ER; these data provide new insights in support of its ER-related, multifunctional roles in organelle biogenesis.
Continental Margin Off Western Africa: Senegal to Portugal

About 22,000 km of continuous seismic-reflection, magnetic, and gravity profiles, 118 radiosonobuoy recordings, 98,000 km of geophysical profiles from previous investigations, 15 deep-sea-drilling logs, and many dredge samples served to reconstruct the history of the continental margin and adjacent deep-ocean floor between Senegal and Portugal. Initial structures of the margin south of Morocco formed by divergence when Africa and North America separated 180 m.y. ago. The margin off western Portugal had a similar origin when the Iberian Peninsula and North America separated about 80 m.y. ago. Between these two divergent segments the area of the Strait of Gibraltar formed by a combination of translation from 180 to 72 m.y. ago and plate convergence from 63 m.y. ago to the p esent, with convergence becoming more intense during the past 10 m.y. Oldest sedimentary rocks atop basement include an evaporite of Late Triassic to Early Jurassic age. When the apron deposited by upbuilding and outbuilding became thick enough, mobility of the evaporites deformed the overlying sediments especially north of the Canary Islands. Except off Morocco and the Strait of Gibraltar and possibly off southern Senegal the sedimentary blanket is dominantly calcareous, reflecting the general lack of fluvial influx. Included is a middle-Late Jurassic algal reef that constitutes the lower continental slope off Morocco. During Aptian-Cenomanian time the deep ocean off much of northwestern Africa had only sluggish bottom circulation, recorded by organic-rich sediments. A major hiatus in deep-ocean sedimentary rocks and in three prominent sedimentary ridges (off Madeira, near Agadir canyon, and north of Conception bank) probably was caused by temporarily intensified circulation. Tertiary tectonics modified the divergent margin south of Morocco by folding of shelf strata off the western High Atlas, emplacement of the Canary Island Ridge, folding of slope strata off Spanish Sahara, and uplift of the Cape Verde plateau. These orogenies also may have uplifted oceanic basement beneath the upper rise and formed the volcanic seamounts along this ridge. Maximum modification by Tertiary diastrophism occurred on the margin of translation-convergence near the Strait of Gibraltar. There, the convergence phase caused uplift of Gorringe bank. Plate convergence also deformed sediments atop oceanic basement, aided by the mobility of Triassic-Jurassic evaporites. More recently, probably because of uplift of the Iberian Peninsula during the Pliocene, well-stratified Miocene and younger deposits atop the deformed lower unit slid oceanward away from the peninsula, with the megaslide coming to rest against the Moroccan continental slope. Associated folding also involved the lower deformed sequence.
ASSESSMENT AND MANAGEMENT OF LARYNGOTRACHEAL STENOSIS

Laryngotracheal stenosis is a congenital or acquired narrowing of the airway representing a continuum of disease that may affect the glottis, subglottis, and trachea. Previously, the term subglottic stenosis was often used (inaccurately) as an inclusive term to describe stenosis occurring anywhere in the airway, because the subglottis was the most common site of stenosis. Rod lens telescopes allow the experienced endoscopist to precisely describe the site and type of airway pathology. The pediatrician's role is critical in this disease in identifying patients with the symptoms of stridor, feeding problems, and atypical (i.e., recurrent, severe, or prolonged) croup. Management of laryngotracheal stenosis in children differs from the management of this disorder in adults. This discussion addresses the causes, diagnosis, and management of laryngotracheal stenosis, emphasizing prevention and the appropriate timing of referral for evaluation by the otolaryngologist or head and neck surgeon.
Reliable control in the presence of sensor/actuator failures: a unified discrete/continuous approach

The authors present observer-based controller designs reliable with respect to failures from a preselected set of sensors or actuators. The design guarantee stability and a H/sub infinity /-norm bound on the closed-loop system despite failures in any subset of that preselected set of actuators and sensors. The results are presented in a unified discrete/continuous setting. >
THE EFFECT OF DIETARY FAT ON VITAMIN B12-METHIONINE INTERRELATIONSHIPS '

It was previously found that raising the fat level of a cornsoybean meal diet from 3 to 22% increased the severity of a vitamin B12deficiency in non-depleted chicks (Spivey, Briggs and Ortiz, '54) and elevated the vitamin B12 requirement (Fox, Ortiz and Briggs, '56). This high vitamin B12require ment could be eliminated by supplemental methionine (Fox, Briggs and Ortiz, '57). The usefulness of this crude diet for vitamin B12 studies was limited since it did not permit the omission or variation in level of most nutrients. In the pres ent paper are reported studies undertaken to duplicate these dietary effects using only purified constituents. A satisfac tory purified diet was developed and the vitamin Bi2-sparing effect of methionine has been studied in chicks fed this diet formulated to contain 0, 4 and 24:% fat. EXPERIMENTAL PROCEDURE
Effect of Subarachnoid Hemorrhage on Cerebral Vasodilatation in Response to Activation of ATP-Sensitive K+ Channels in Chronically Hypertensive Rats

Background and Purpose Cerebral vasodilatation in response to aprikalim, an opener of ATP-sensitive K+ channels, is selectively augmented after subarachnoid hemorrhage (SAH). Vasodilatation in response to activation of ATP-sensitive K+ channels, however, is impaired during chronic hypertension. Hypertension may contribute to a worse outcome after SAH, but the nature of the relationship between hypertension and SAH is uncertain. In the present study we examined responses of the basilar artery to aprikalim after SAH in normotensive Wistar-Kyoto rats (WKY) and stroke-prone spontaneously hypertensive rats (SHRSP). Methods In anesthetized WKY and SHRSP, we measured changes in diameter of the basilar artery in response to aprikalim and papaverine using a cranial window 2 days after injection of 0.3 mL saline or autologous blood into the cisterna magna. Results Under control conditions, aprikalim (0.1 to 1 μmol/L) and papaverine (10 to 100 μmol/L) produced dilatation of the basilar artery. After SAH, responses t...
Results from a nuclear microprobe analysis of selected rare earth fluor materials

Until recently, it was difficult to measure properties of individual fluor grains. The development of an accelerator-based nuclear microprobe, as is currently available at the Louisiana Accelerator Center, has made this type of research possible. Using ion beams as small as 1 /spl times/ 1 /spl mu/m (horizontal /spl times/ vertical extent), it is now possible to measure properties of individual fluor grains. Starting in 2000, a research program was initiated to determine the microscopic fluorescence properties for selected rare earth compounds, like Y/sub 2/O/sub 2/S:Eu. Particle-induced X-ray emission (PIXE) was used to characterize individual fluor grains. Individual Y/sub 2/O/sub 2/S:Eu grains are clearly visible in the analysis and are less than 10 /spl mu/m in extent.
MODBASE, a database of annotated comparative protein structure models.

MODBASE (http://guitar.rockefeller.edu/modbase) is a relational database of annotated comparative protein structure models for all available protein sequences matched to at least one known protein structure. The models are calculated by MODPIPE, an automated modeling pipeline that relies on PSI-BLAST, IMPALA and MODELLER. MODBASE uses the MySQL relational database management system for flexible and efficient querying, and the MODVIEW Netscape plugin for viewing and manipulating multiple sequences and structures. It is updated regularly to reflect the growth of the protein sequence and structure databases, as well as improvements in the software for calculating the models. For ease of access, MODBASE is organized into different datasets. The largest dataset contains models for domains in 304 517 out of 539 171 unique protein sequences in the complete TrEMBL database (23 March 2001); only models based on significant alignments (PSI-BLAST E-value < 10(-4)) and models assessed to have the correct fold are included. Other datasets include models for target selection and structure-based annotation by the New York Structural Genomics Research Consortium, models for prediction of genes in the Drosophila melanogaster genome, models for structure determination of several ribosomal particles and models calculated by the MODWEB comparative modeling web server.
Pulse radiolysis studies of styrene

We have applied the pulse radiolysis technique of studying short-lived, radiation-produced intermediates to a study of pure, dry liquid styrene. We have observed at least three distinct species. The most rapidly decaying species (τ1/2 = 4 μsec., λmax ≈ 370 mμ) exhibits an apparent first-order decay which is slowed down in the presence of dry oxygen, occurs too rapidly to be measured in the presence of water, and has a temperature coefficient of approximately 1 kcal./mole between 25 and 45°C. We have tentatively identified the species as the styryl anion with a G value for formation of approximately 0.15. A second species (τ1/2 = 220 μsec. λmax ≈ 320–330 mμ) exhibits a first-order decay which appears to be independent of oxygen and water. From its spectrum, we have tentatively identified it as the styryl radical. The third species (λmax ≈ 310 and 320 mμ) is relatively stable in the dark, but is radily photolyzed by the analyzing light of the usual experimental set-up for pulse radiolysis studies. The formation of this species appears to be independent of the water and oxygen content of the styrene.
Reliability and Validity of Five-Level Response Continua for the Career Decision Self-Efficacy Scale

The present study, based on three samples of college students totaling 1,832 participants, resulted in the conclusion that a 5-level response continuum for the short form of the Career Decision Sel...
Song learning and social interaction in indigo buntings

Abstract Indigo buntings ( Passerina cyanea ) isolated as individuals from 60 days of age developed abnormal songs. Birds isolated in groups for 9 to 10 months and then individually isolated developed slightly more normal songs but lacked the adult song figures. Birds copied the songs of adult tutors with whom they interacted socially. Birds with two tutors copied the songs of tutors that they could see and join in supplanting behaviour, but not songs of tutors from which they were visually isolated. One song was transmitted culturally across three generations under experimental conditions. The importance of social factors in song development of yearling buntings explains the development of local groups of males that share songs or dialects with each other in the field.
Multi-muscle EMG pattern study of anterior cruciate ligament (ACL) injured subjects

Electromyogram (EMG) linear envelope (LE) patterns of anterior cruciate ligament injured subjects are studied. Six muscles around the knee joints, the rectus femoris (RF), vastus lateral (VL), vastus medialis (VM), semitendinosus (ST), biceps femoris (BF), and medial gastrocnemius (GS), are analyzed. The results of a clustering analysis show that some clusters of patterns are mainly composed of ACL-injured subjects and contain somewhat different patterns from those of normal subjects: the ST bursts later than usual, the BF activates earlier, and the minor activity peak around toe-off of the quadriceps (RF, VL, VM) disappears. >
Pemphigus vulgaris and pregnancy: risk factors and recommendations.

Pemphigus vulgaris during pregnancy is exceedingly rare; only 15 cases with immunopathologic confirmation have been reported. In the four cases associated with fetal mortality the mother's disease was active and required high doses of corticosteroids and adjuvant therapy with azathioprine or dapsone for control. A pregnant woman with limited disease is described, At the time of delivery her pemphigus vulgaris antibody titer was 1:640. A full-term, healthy male infant was completely free of skin lesions after a spontaneous vaginal delivery.
Is Proton Pump Inhibitor Use Associated With Risk of Myocardial Infarction

STAFF OF CONTRIBUTORS Joseph Anderson, White River Junction, VT Johanna L. Chan, Houston, TX Matthew A. Ciorba, St. Louis, MO Massimo Colombo, Milan, Italy Gregory A. Cote, Charleston, SC Evan S. Dellon, Chapel Hill, NC Alex Ford, Leeds, United Kingdom Lauren B. Gerson, San Francisco, CA David S. Goldberg, Philadelphia, PA Samir Gupta, San Diego, CA Reena Khanna, London, Ontario, Canada W. Ray Kim, Rochester, MN Paul Y. Kwo, Indianapolis, IN Uma Mahadevan, San Francisco, CA Baha Moshiree, Miami, FL Swati G. Patel, Ann Arbor, MI Laurent Peyrin-Biroulet, Vandoeuvre-les-Nancy, France Jesus Rivera-Nieves, San Diego, CA Sameer Saini, Ann Arbor, MI Ekihiro Seki, Los Angeles, CA Amit Singal, Dallas, TX Ryan W. Stidham, Ann Arbor, MI Akbar Waljee, Ann Arbor, MI Sachin Wani, Aurora, CO Alastair J. M. Watson, Norwich, United Kingdom Yana Zavros, Cincinnati, OH