cssi/SciSciGPT-SciSciNet huggingface dataset:
The human immunodeficiency virus type-1 long terminal repeat and its role in gene expression.

Publisher Summary This chapter discusses: (1) the approaches for studying human immunodeficiency virus type-1 (HIV-1) gene expression; (2) the activation signals for HIV-1 gene expression; (3) the HIV-1 cis-acting control elements in the long terminal repeat (LTR) involved in transcriptional initiation; (4) elongation; and (5) the processing of RNA as well as translational control. The structural and mechanistic features of tat-activation and interventional strategies for the inhibition of HIV-1 gene expression are explained in the chapter. Recent studies indicate that HIV-1 gene expression may be active, throughout infection in a subset of cells, within the lymph nodes of infected individuals. At the same time, most infected cells may retain HIV-1 in a dormant stage. The LTR elements of the integrated proviral HIV-1 genome serve as the transcriptional initiation site at the 5' end of the genome. The LTR contains an element known as the trans-activation responsive (TAR) region, the target for the HIV-l-encoded viral transactivator protein tat. In addition, the reading frame of the HIV-l-encoded protein, nef, overlaps the 5' aspect of the LTR that likely places constraints on sequence variation and composition in this portion of the LTR.
Diffusion Tensor MR Imaging

This unit reviews the physical principles and methodologies involved in diffusion-weighted imaging (DWI) and diffusion tensor imaging (DTI) for clinical applications. Diffusion-sensitive MRI noninvasively provides insight into processes and microscopic cellular structures that alter molecular water mobility. Formalism to extend the Bloch equation to include effects of random translational motion through field gradients is reviewed. Definition of key acquisition parameters is also reviewed along with common methods to calculate and display tissue diffusion properties in a variety of image formats. Characterization of potential directional-dependence of diffusion (i.e., anisotropy), such as that which exists in white matter, requires DTI. Diffusion tensor formalism and measurement techniques then reduce the diffusion tensor into standard anisotropy quantities that are summarized along with commonly used methods to depict directional information in an image format. Keywords: Diffusion MRI; Anisotropy; Tensor; Methods
Polyunsaturated fatty acids in the food chain in the United States

In the United States, intake of n-3 fatty acids is approximately 1.6 g/d ( approximately 0.7% of energy), of which 1.4 g is alpha-linolenic acid (ALA; 18:3) and 0.1-0.2 g is eicosapentaenoic acid (EPA; 20:5) and docosahexaenoic acid (DHA; 22:6). The primary sources of ALA are vegetable oils, principally soybean and canola. The predominant sources of EPA and DHA are fish and fish oils. Intake data indicate that the ratio of n-6 to n-3 fatty acids is approximately 9.8:1. Food disappearance data between 1985 and 1994 indicate that the ratio of n-6 to n-3 fatty acids has decreased from 12.4:1 to 10.6:1. This reflects a change in the profile of vegetable oils consumed and, in particular, an approximate 5.5-fold increase in canola oil use. The ratio of n-6 to n-3 fatty acids is still much higher than that recommended (ie, 2.3:1). Lower ratios increase endogenous conversion of ALA to EPA and DHA. Attaining the proposed recommended combined EPA and DHA intake of 0.65 g/d will require an approximately 4-fold increase in fish consumption in the United States. Alternative strategies, such as food enrichment and the use of biotechnology to manipulate the EPA and DHA as well as ALA contents of the food supply, will become increasingly important in increasing n-3 fatty acid intake in the US population.
Unstable vortices in the near region of an internal flow cavity

This paper presents experimental data taken in the forward region of a separated internal free-shear layer produced in an internal cavity flowfield. It has been found that in the region very near the forward restrictor, experimental velocity profiles agree closely with the exact Stuart instability velocity profile with various values of a steepness parameter. Reynolds shear-stress profiles suggest the presence of counter-rotating longitudinal vortices. Spectral analysis by the maximum entropy method of the time samples within the vortices indicates subharmonic and harmonic components of the fundamental frequency, with a weak indication of the fundamental frequency itself.
Why Save a Can

This activity ties together the recycling of aluminum and the protection of rain forests. Students use critical thinking to study the effects of open pit mining of bauxite in rain forests and then draw their own conclusions about how to minimize the impact of bauxite mining and boost recycling efforts within their communities. Drawing conclusions exercises students' problem-solving skills, and the hands-on approach throughout the activity promotes student participation and critical thinking. In an evaluation of the activity, middle school students reported that they learned where aluminum comes from, and 85% rated the activity with the highest score for enjoyment.
Sebaceus and Becker’s Nevus: Overview of Their Presentation, Pathogenesis, Associations, and Treatment

Nevus sebaceus (NS) and Becker's nevus (BN) are two variants of epidermal nevi. NS clinically presents as a yellowish-orange, hairless plaque on the scalp, face, or neck, while BN presents as a tan-to-brown hyperpigmented, sometimes hypertrichotic, plaque typically on the chest and shoulder. Histologically, NS displays mature or nearly mature sebaceus glands as well as acanthosis and fibroplasia of the papillary dermis. BN shows variable papillomatosis, acanthosis, and hyperkeratosis, with hyperpigmentation of the basal/suprabasal layer. While the genetic basis of NS is thought to be due to post-zygotic mutations in the Harvey rat sarcoma viral oncogene homolog (HRAS)/Kristen rat sarcoma viral oncogene homolog (KRAS) genes, the genetic basis of BN is relatively unknown and is implicated with paradominant inheritance. In some patients, NS and BN can each be associated with additional cutaneous and extra-cutaneous anomalies, ranging from benign or malignant tumors to multiple organ irregularities. Due to the wide range of possible associations, treatment for NS and BN is devised on a case-by-case basis. In this article, we review the features, etiology, and diagnosis/management of NS and BN, with a focus on associations. We also report a patient who concomitantly presents with both lesions.
Pharmacokinetics of Dichloroacetate in Adult Patients with Lactic Acidosis

The pharmacokinetic properties of the lactate-lowering drug dichloroacetate were investigated in 111 adult patients with lactic acidosis who were randomized to receive dichloroacetate as part of a placebo-controlled clinical trial. The clinical symptoms and etiology of lactic acidosis varied markedly among patients. Dichloroacetate, at a dose of 50 mg per kilogram of body weight, was administered in a 30-minute intravenous infusion into a peripheral vein. A second dose, identical to the first, was administered 2 hours after beginning the first infusion. Plasma levels of dichloroacetate were determined from blood samples collected periodically up to 288 hours after administration and the data were subjected to pharmacokinetic modeling. The pharmacokinetic properties of dichloroacetate in these acutely ill patients were complex and differed markedly from those in healthy volunteers, whose data fitted a one-compartment pharmacokinetic model. In contrast, the data from patients fitted one-, two-, or three-compartment pharmacokinetic models or even none of these, depending on the individual. Drug clearance in plasma tended to decrease as the number of compartments required to fit the data increased or as the number of drug treatments increased.
Accuracy of eyewitness memory for persons encountered during exposure to highly intense stress.

Charles A. Morgan III*, Gary Hazlett, Anthony Doran, Stephan Garrett, Gary Hoyt, Paul Thomas, Madelon Baranoski, Steven M. Southwick Associate Professor of Psychiatry, Department of Psychiatry, Yale University School of Medicine, Connecticut Mental Health Center, Law and Psychiatry Division, 34 Park Street, New Haven, CT 06519-1187, USA Major, JFK Special Warfare Training Center and School, United States Army, Fort Bragg, NC, USA Lieutenant Commander, United States Navy, FASOTRAGRULANT, Naval Air Station, Brunswick, ME, USA Physician Associate, Yale University School of Medicine, New Haven, CT, USA Lieutenant Commander, United States Navy, FASOTRAGRUPAC-N2, Naval Air Station, North Island, Coronado, CA, USA Assistant Clinical Professor of Psychiatry, Department of Psychiatry, Yale University School of Medicine, Connecticut Mental Health Center, Law and Psychiatry Division, 34 Park Street, New Haven, CT 06519-1187, USA Professor of Psychiatry, Department of Psychiatry, Yale University School of Medicine, Connecticut Mental Health Center, Law and Psychiatry Division, 34 Park Street, New Haven, CT 06519-1187, USA
Synaptic remodeling in the arcuate nucleus during the estrous cycle is induced by estrogen and precedes the preovulatory gonadotropin surge

We have shown that the ovarian cycle is accompanied by a fall in the axosomatic synapses on randomly selected neurons of the arcuate nucleus by the morning of estrus, with a return to the preovulatory levels by the morning of metestrus, indicating a possible role in positive feedback. However, it remains to be proven that the circulating estradiol is the actual regulator of this physiological synaptic plasticity, or that estrogen-induced synaptic retraction precedes in the surge of gonadotropins at midcycle. To resolve these questions, we used an estradiol-immunoneutralization protocol and studied arcuate nucleus axosomatic synapses during the critical points of the estrous cycle. In addition to blocking positive feedback, estrogen immunoneutralization abolished synaptic retraction in the arcuate nucleus. As a positive control, the nonbinding estrogen diethylstilbestrol maintained the gonadotropin surge and synaptic retraction in the antiestradiol-treated animals. Furthermore, in the diluent-treated cycli...
The Lived Perioperative Experience of Ambulatory Surgery Patients

Understanding patients' perspectives is central to providing appropriate nursing care. The purpose of this study was to explore ambulatory surgery patients' perceptions and views of the perioperative experience. A phenomenological study was conducted that included 16 patients who underwent abdominal surgical procedures in the ambulatory surgery center of a large teaching hospital in the northeastern United States. Intensive semistructured interviews were used to collect data. Patients were interviewed one week after surgery. Data analysis was aimed at gaining understanding of the lived experience of ambulatory surgery patients. Themes identified included fear, knowing, and presence. Results indicate that patients in this study were not prepared adequately for the perioperative experience, suffered needlessly due to inadequate pain management, and did not achieve discharge readiness.
Molecular dynamics simulations of helix and turn propensities in model peptides

Helices, β-structures, turns and hydrophobic cores are key substructures of proteins, conferring stability on the native conformation, and functioning as early intermediates in the folding process. Molecular dynamics calculations, both as free dynamics simulations and as free energy calculations, are being used to uncover details of the equilibria and kinetics of formation and inter-conversion of these structures in model oligopeptides. This theoretical development parallels experimental studies with synthetic oligopeptides elsewhere.
Nepalese Journalists: Idealists, Optimists, and Realists

This article provides a profile of Nepalese journalists in terms of their opinions about traits of government and private media, influences on their reporting, press freedom in Nepal, and their pro...
Culture-Bearing Units and the Units of Culture: An Introduction

The articles that follow explore two issues. First, is it possible to differentiate empirically useful culture-bearing units from one another? If it is possible in principle, how can it be accompli...
Effects of dietary preference and galanin administration in the paraventricular or amygdaloid nucleus on diet self-selection

Microinjection of galanin into the paraventricular nucleus (PVN) of the hypothalamus has been reported to predominantly increase dietary fat consumption during the light or late dark periods. However, there have been no studies of the macronutrient-specific effects of galanin administered into the amygdala (AMY). We used male Sprague-Dawley rats to test the effect of galanin administered into the PVN or central nucleus of the AMY on diet selection using two different protocols: the two-choice composite diet (10% or 55% energy as fat) (Study 1) or the three-choice macronutrient diet (Study 2). In the first study, total food intake was significantly increased 60 min after galanin injection (0.3 nmol) into either the PVN or AMY, but there was no difference in intake between the low- and high-fat diets. In Study 2, using the three-choice macronutrient diet, the feeding stimulation produced by galanin in the PVN also was not diet-dependent. In the AMY, there was a significant effect of diet on the feeding response to galanin, due primarily to the lack of stimulation of protein intake, whereas the intakes of fat and carbohydrate were not significantly different. In summary, there was no difference in the effect of galanin on fat versus carbohydrate intake for either nuclei, whether animals were injected during the light or the late-dark phase. Because rats often display preferences when allowed to choose among individual macronutrient sources, we also examined the relationship between baseline macronutrient preference and the feeding response to galanin in groups of highly fat-preferring and carbohydrate-preferring rats (Study 3). After PVN galanin injection, fat-preferring rats demonstrated significant increases in their consumption of both carbohydrate and fat, whereas carbohydrate-preferring rats responded by eating carbohydrate almost exclusively. There were significant positive associations between baseline macronutrient intake and galanin-induced intake. The results of these studies combined suggest that the effect of galanin on macronutrient selection is not specific for fat and that underlying macronutrient preferences are important in determining the feeding response to galanin.
Self-tuning fault diagnosis of MEMS

Multiple-model adaptive estimation techniques have been previously successfully applied to fault diagnosis of microsystems. Their diagnosis performance highly depends on the accuracy of modeling techniques used in representing faults. This paper presents the application of a self-tuning forgetting factor technique in the modeling of faults in MEMS and its effects on diagnosis performance compared with the application of Kalman filters and fixed gain estimation techniques. The self-tuning-based modeling used in the diagnosis algorithm was experimentally implemented. It demonstrated superior results compared to Kalman filter and fixed gain estimation techniques by accelerating the diagnosis process.
Novel thermoplastic elastomers. II. Properties of star-block copolymers of PSt-b-PIB arms emanating from cyclosiloxane cores †

Select mechanical, thermal, and rheological properties of star-blocks consisting of 5–21 polystyrene-b-polyisobutylene (PSt-b-PIB) arms radiating from cyclosiloxane cores are described. The tensile properties of products containing 23–41 wt % of PSt are substantially higher (9.6–23.8 MPa) than those of linear triblocks of comparable arm molecular weights and compositions over the 25–85°C temperature range. The mechanical properties of star-blocks seem to be much less sensitive to diblock contamination than linear triblock thermoplastic elastomers of similar hard/soft segment composition. The tensile strength of star-blocks increases by increasing the number of arms (Nw,arm) and reaches a plateau in the Nw,arm = 5–10 range. Star-blocks exhibit higher strengths with lower PSt segmental Mn than linear triblocks. Solvent cast triblock copolymers exhibit higher tensile strengths than compression molded products; however, star-blocks show no significant property differences between cast and molded samples. The dynamic melt viscosities of the star-blocks are substantially lower than those of linear triblocks with comparable hard/soft segment compositions, which is consistent with the star's unique microarchitecture and should lead to improved overall processibility. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 815–824, 1999
Evidence of possible tectonic upwarping along the South Carolina coastal plain from an examination of river morphology and elevation data

Although the fault(s) responsible for the 1886 Charleston, South Carolina, earthquake have not yet been identified (primarily because of the lack of surface rupture), evaluation of Landsat imagery, aerial photography, and topographic maps have revealed an ∼200-km-long, ∼15-km-wide, north- northeast-trending zone composed of subtle topographic highs and morphologic changes in rivers that may be associated with tectonic activity. River anomalies observed within this zone include river bends that are convex toward the north- northeast, incised channels, changes in river patterns, and convex-upward longitudinal profiles. Analyses of geologic and geophysical data further indicate that these surface features may be the result of ongoing tectonic uplift along a north-northeast-trending fault zone possibly associated with recent seismicity near Charleston.
Molecular interaction studies of vascular endothelial growth factor with RNA aptamers

With widespread applications in biosensors, diagnostics and therapeutics, unraveling the mechanism of the interactions between aptamers and their targets has become extremely important. In this study, the interaction forces between an aptamer and its protein target were successfully measured via AFM-based force spectroscopy at the molecular level. The angiogenic protein, vascular endothelial growth factor (VEGF(165)) covalently tethered to a mixed self-assembled monolayer surface and an anti-VEGF(165) aptamer attached to an AFM cantilever was used to probe this interaction. By comparing the binding probability and the force distribution of this system in a series of experiments, the interaction between the aptamer and the protein was confirmed and the effect of loading rate on the rupture force was studied. The specificity of the aptamer was investigated by measuring interactions with VEGF(121), an isoform of VEGF missing a critical binding domain, and VEGF(165) isoform blocked with heparin. The lower frequency of binding events compared with that of VEGF(165) reflected that despite a high affinity to its preferential target, the selectivity of this aptamer is impaired to some extent due to the flexible structure of aptamers. By changing the concentration of Mg(2+) ion in the binding buffer, we could verify the effect of metal ions as stabilizers of aptamer conformation. The results provide evidence at the molecular level that the structural stability of aptamer is closely related to higher binding force and that rigid aptamer tertiary structures require higher forces to unbind the aptamer/protein complex.
Use of sibutramine and other noradrenergic and serotonergic drugs in the management of obesity.

Drugs that act through noradrenergic and serotonergic mechanisms have historically served as the mainstays of pharmacologic treatments for obesity. This review addresses the following three topics: a brief discussion of older weight loss medications approved for short-term use (benzphetamine, phendimetrazine, diethylpropion, mazindol, and phentermine), as well as over-the-counter adrenergic drugs (phenylpro-panolamine and ephedrine); recent clinical studies documenting the safety and efficacy of a new medication for obesity treatment, sibutramine, recently approved by the Food and Drug Administration for long-term use; and recent studies characterizing the valvulopathy associated with fenfluramine and dexfenfluramine, serotonergic medications for obesity which have been removed from the markets.
On the Kolmogorov-Zakharov spectra of weak turbulence

Abstract Zakharov discovered that wave kinetic equations for weak turbulence have exact power-law solutions which are similar to the Kolmogorov spectrum of hydrodynamic turbulence. We present a considerably simplified derivation of these solutions, i.e. Kolmogorov–Zakharov spectra. Even to a greater extent we simplify the derivation of certain “universal” corrections to these spectra, obtained by Kats and Kontorovich. The technique is utilized as well to derive the expressions for the so-called Mellin functions (that describe the behavior of weak turbulence in the vicinity of the Kolmogorov–Zakharov spectra). Using this general approach, we obtain Kolmogorov–Zakharov spectra for a class of weak turbulent media with dissipative nonlinearity. We also find a large family of anisotropic spectra, which are exact solutions of the corresponding kinetic equation. As a physical example, we consider the plasma turbulence when the main nonlinear process is the scattering of plasmons by electrons.
A general mechanism of martensitic nucleation: Part I. General concepts and the FCC → HCP transformation

Consideration of the martensitic nucleation process as a sequence of steps which take the particle from maximum to minimum coherency leads to the hypothesis that the first step in martensitic nucleation is faulting on planes of closest packing. It is further postulated that the faulting displacements are derived from an existing defect, while matrix constraints cause all subsequent processes to occur in such a way as to leave the fault plane unrotated, thus accounting for the observed general orientation relations. Using basic concepts of classical nucleation theory, the stacking fault energy is shown to consist of both volume energy and surface energy contributions. When the volume energy contribution is negative, the fault energy decreases with increasing fault thickness such that the fault energy associated with the simultaneous dissociation of an appropriate group of dislocations (e.g. a finite tilt boundary segment) can be zero or negative. This condition leads to the spontaneous formation of a martensitic embryo. For the specific case of the fcc → hcp martensitic transformation in Fe-Cr-Ni alloys, the defect necessary to account for spontaneous embryo formation at the observedM s temperatures may consist of four or five properly spaced lattice dislocations. Such defects are considered to be consistent with the known sparseness of initial martensitic nucleation sites.
P-glycoproteins in pathology: The multidrug resistance gene family in humans☆

Many cancers do not respond to chemotherapy on primary exposure to drugs, thus manifesting intrinsic drug resistance. Other cancers that do initially respond subsequently become resistant to the same drugs and simultaneously to other drugs to which the patient has had no previous exposure. This is a form of acquired drug resistance. There is a pressing need to better understand the mechanisms of drug resistance and to use this information to develop strategies for the chemosensitization of drug-resistant tumors. A goal of the pathology laboratory is to offer chemosensitivity tests that identify intrinsic or acquired resistance of tumors to specific drugs or classes of drugs to enable the clinician to tailor therapy to the biology of cancers in individual patients. Multidrug resistance is one type of drug resistance. It can be present in either an intrinsic or acquired form. The human gene that confers human multidrug resistance, the MDR1 gene, has been cloned and classified as a member of the MDR gene family. Its encoded protein, called Mdr1, is an energy-driven membrane efflux transporter that maintains intracellular concentrations of certain chemotherapeutic drugs at nontoxic levels. Useful model systems for studying multidrug resistance have been developed in several research laboratories. Applying selection pressure by exposing cultured cancer cells to escalating doses of natural product anti-cancer drugs allows cross-resistant cell lines to be produced which share patterns of drug resistance with human cancers. A common feature of these drug-resistant lines is the expression of Mdr1. Using techniques of genetic engineering, molecular probes have been developed that can be used to measure MDR1 mRNA and MDR1 gene amplification. Mdr can be measured by immunochemistry methods. Currently, such measurements are being used to stratify patients in clinical trials designed to determine if chemosensitization by inhibition of the pump function of Mdr is a clinically useful therapeutic strategy. If successful, Mdr/MDR1 mRNA laboratory testing might significantly increase the clinical laboratory's role in cancer patient management.
Path planning for optimal classification

As stated in the Office of the Secretary of Defense's Unmanned Aircraft Systems Roadmap 2005–2030, reconnaissance is the number one priority mission for Unmanned Air Vehicles (UAVs) of all sizes. During reconnaissance missions, classification of objects of interest (e.g, as friend or foe) is key to mission performance. Classification is based on information collection, and it has generally been assumed that the more information collected, the better the classification decision. Although this is a correct general trend, a recent study has shown it does not hold in all cases. This paper focuses on presenting methods to plan paths for unmanned vehicles that optimize classification decisions (as opposed to the amount of information collected). We consider an unmanned vehicle (agent) classifying an object of interest in a given area. The agent plans its path to collect the information most relevant to optimizing its classification performance, based on the maximum likelihood ratio. In addition, a classification performance measure for multiple measurements is analytically derived.
Pediatric HIV-related Mortality Characteristics at the Time of Death(TOD): Comparison of experience in 1990 and 1996. † 720

The number of early deaths in infants vertically infected with HIV infection have decreased in frequency probably as a result of the primary antimicrobial prophylaxis for PCP. Recent analyses estimate the mean survival time for a child with vertically acquired HIV infection to be over 9 years. We compared the characteristics of HIV-infected children who died at our center in 1990 to those who died in 1996 to determine how the characteristics of illness and mortality in vertically HIV infected children have evolved.Table
Hydrodynamic analysis of a Banbury mixer

A fluid dynamics analysis package—FIDAP—using a finite element method was employed to simulate the flow patterns in a Banbury mixer. The flow simulations were carried out only for the intensive mixing region, and they were limited to a two-dimensional analysis. A Lagrangean point of view was adopted and 18 different geometries were selected to represent one revolution of the rotor. A power-law model with time and temperature dependent parameters was used to characterize the rheological behavior of the mixture. Steady-state, isothermal flow simulations as well as a transient, non-isothermal flow analysis were performed for a Banbury B mixer. The results of the analysis show good agreement with experimental observations regarding the development of vortices, the pressure, and the temperature profiles.
Investigation into Structural Changes of the Copper Binding Site in Lysyl Oxidase upon Substrate and Inhibitor Docking

The present paper reports a computational investigation of potential communication between the lysine tyrosylquinone (LTQ) and copper cofactors within lysyl oxidase (LOX). Various substrates and inhibitors of LOX were docked into the active site in our computer generated model of the enzyme. Conformational changes in the vicinity of the copper site as well as changes in the electrostatic environment were identified. The appearance of a canal-like structure involving tyrosine 35 (TYR35) and glutamine 104 (GLN104) residues was shown to be consistent upon docking of a variety of different compounds. Interactions between LOX and its natural substrate, collagen, were also explored through molecular dynamic simulations. The possibility of communication between the organic and inorganic cofactors in LOX was proposed, aiding the ongoing debate regarding the role of copper in the catalytic mechanism of this important enzyme.
A replication model for sister-chromatid exchange

Abstract A model for the production of sister-chromatid exchanges is presented, based on the idea that double-strand breaks are generated at junctions between a completely duplicated replicon cluster and a partially duplicated replicon cluster. Agents that induce absolute blocks to DNA fork displacement will cause this condition to persist longer than normal, whereas agents that inhibit initiation of whole clusters will rarely cause it at all. During the blunt-end repair of the double-strand breaks, sister-chromatid exchange would be initiated when daughter strands of a duplicated cluster recombine with the parental strands of the partially replicated cluster. When the latter finishes replication, sister-chromatid exchange would be completed.
The Influence of Damselfly Naiads, Phytoplankton, and Selected Physicochemical Factors on the Population Growth of Daphnia schødleri

ABSTRACT The effect of selected biotic and abiotic factors on the population growth rate of Daphnia schodleri was studied over a five month period in a wetland ecosystem. Among the factors studied, only the density of damselfly naiads with head capsule width greater than 2.0 mm was significantly correlated with D. schodleri's population growth rate. The presence of small and medium damselfly naiads did not affect the D. schodleri population growth rate. No significant correlations with growth rate were observed for high and low quality phytoplankton, water temperature, dissolved oxygen, pH, turbidity, or photoperiod.
Energy storage and deposition in a solar flare.

High temporal and spatial resolution solar X-ray pictures of a flare at 1827 UT on 5 September 1973 were taken with the S-056 Aerospace Corporation/Marshall Space Flight Center telescope on the Apollo Telescope Mount. Photographs taken at 9 s intervals allow detailed information to be obtained about the site of the energy release, as well as about the evolution of the flare itself. Observations show that the flare occured in an entire arcade of loops rather than in any single loop. Sequential brightening of different X-ray features indicates that some excitation moved perpendicular to the magnetic field of the arcade at velocities of 180–280 km/s. The most intense X-ray features were located in places where the magnetic field composing the arcade had a small radius of curvature with horizontal field gradients higher than the surrounding region and where the axis of the arcade changed direction. We feel that the arcade geometry strongly influenced the propagation of the triggering disturbance, as well as the storage and site of the subsequent deposition of energy. A magnetosonic wave is suggested as the propagating mechanism triggering instabilities that may have existed in the preflare structure. This event demonstrates that all energy emitted during a flare need not be released immediately nor in the same location, thereby eliminating some problems encountered in many flare theories. Conditions for energy release are discussed.
Experimental and Numerical Investigation of Forced Convective Characteristics of Arrays of Channel Mounted Obstacles

An experimental investigation of the forced convective heat transfer of individual and arrays of multiple two-dimensional obstacles is reported. The airflow rate was varied from 800 < ReDh =s 13000. The effects upon the Nusselt numbers and obstacle temperature differences of parametric changes in the Reynolds number, channel height, array configuration, and input heat flux are established. The input heat fluxes to the obstacles ranged from 950 < q" == 20200 W/m2, which significantly extends beyond that seen in the open literature for forced convective air cooling of simulated electronic components. Comparisons of the obstacle mean Nusselt numbers are made with a two-dimensional laminar numerical model employing the Navier-Stokes equa­ tions. A set of correlations characterizing the heat transfer from the protruding heat sources within the channel is obtained. It was found that the obstacle temperature, the critical measure for electronic device failure, must be shown along with the corresponding Nusselt number to fully characterize the thermal state of the heated obstacle as the ratio definition of the Nusselt number can obscure large temperature increases. The results find that the proper placement of geometrically dissimilar obstacles, such as a taller obstacle, can be used to passively enhance the heat transfer in its vicinity. This effect would be dependent upon the flow rate and geometries in order to control the reattachment zones and their subsequent convective augmen­ tation. The experimental results are found to be in good agreement with the results from the numerical simulation. Finally, a set of pertinent correlations for the arrays of channel mounted obstacles is given.
Focusing on the Efficacy of Tizanidine in the Multiple Sclerosis Clinic

ABSTRACT The use of tizanidine is well established in spasticity due to multiple sclerosis (MS), spinal cord injury, and cerebrovascular disease. Refinement of the use oftizanidine in these areas is ongoing. To date, most large studies have focused primarily on measurement of changes in abnormalities of tone and spasm frequency rather than changes related to improved function. More detailed studies may help to better elucidate the impact of tizanidine and other spasticity treatments on activities of daily living and overall quality of life of MS patients. (Int J MS Care. 2001; 3(1): 29–31)
Navy jet fuel production during a military mobilization scenario

Abstract Refinery linear programming models have been used to estimate the regional production of U.S. Navy jet fuel for a military mobilization scenario based on a substantial loss of Persian Gulf crude oil production and the loss of all Venezuclan petroleum exports. In the scenario, the demand for all U.S. military fuels is assumed to have tripled. The effects of these scenario conditions are mitigated by the use of strategic petroleum reserves and by the sharing agreements of the International Energy Agency. The analysis suggests that, without market over-rides, Navy jet-fuel requirements might not be met in the strategically important U.S. West Coast and the foreign Pacific regions.
Petrogenesis of the Superstition-Superior Volcanic Area as Inferred from Strontium- and Oxygen-Isotope Studies

Apparent initial Sr 87 /Sr 86 ratios of five ash-flow tuffs (0.7063 to 0.7139) and several mafic to silicic lavas (0.7055 to 0.7131) indicate that the magmas were derived below the base of the Precambrian granitic crust (0.7231 to 1.0906). Liquidus compositions in the system Q-Or-Ab-H 2 O and oxygen-isotope geother-mometry suggest that the silicic magmas started to crystallize quartz, magnetite, and two feldspars in a water-undersaturated environment of high pressure (∼10 kb) and moderate temperature of at least 830°C. During or after ascent into the crust, the magmas underwent varying degrees of crystal-melt re-equilibration. Measured plagioclase-biotite O 18 fractionations (0.5 to 0.7) imply a temperature that is too high for the observed mineral assemblage, and the inference is that the two minerals did not crystallize in equilibrium. Prior to eruption, the upper part of the magma column assimilated crustal Sr such that the base of each ash flow is now enriched in Sr 87 . In some cases, this assimilation was too rapid to allow crystal-melt equilibration of Sr isotopes. δO 18 values for the magmas are within the range typical of similar magma types, indicating that no significant interaction took place between the melts and meteoric water; however, some rocks have exchanged oxygen isotopes with meteoric water at low temperatures after eruption. Some of the magma appears to have had a long residence in the crust at lower pressure (1 kb) and temperature (750°C), because two of the ash-flow tuffs and one lava are greatly enriched in Sr 87 and have largely re-equilibrated under the P-T conditions of a shallow magma chamber. Even these, however, have retained evidence for a multistage genesis.
CHARACTERIZATION OF VOLATILE ORGANIC COMPOUNDS ON AIRBORNE DUST IN A SWINE FINISHING BARN

Three methods of extracting volatile organic compounds (VOCs) adsorbed on the airborne dust in a swine finishing building were investigated: solvent extraction using dichloromethane, solid-phase microextraction (SPME) using carboxen/ polydimethylsiloxane (CAR/PDMS) and PDMS fibers, and purge and trap. Airborne dust was first collected in pre-baked glass-fiber filters and analyzed using each of the three methods. Solvent extraction with dichloromethane extracted only some high-boiling point carboxylic acids. The SPME CAR/PDMS fiber extracted the low- to mid-boiling point VOCs such as the carboxylic acids, phenols, and indoles; while the PDMS fiber extracted more of the mid-boiling point compounds, specifically the aliphatic hydrocarbons, indoles, and some aldehydes. The purge and trap method extracted compounds with low- to mid- boiling points including volatile carboxylic acids, aldehydes, alcohols, ketones, indoles, and esters. Quantitative analysis of five selected VOCs (i.e., acetic acid, propionic acid, butyric acid, hexanal, and nonanal) using the purge and trap method showed acetic acid as generally the most abundant and nonanal as the least abundant.
The electric dipole moment of the neutron in the Skyrme model

Abstract We use the Skyrme model to estimate the contribution of the QCD θ-angle to the neutron's electric dipole moment D n , and find D n = 2 × 10 −6 θ e cm . The same method may also be used to estimate the contributions to D n of higher-dimension CP -violating operators.
User interface and agent prototyping for flexible working

A collaborative work group that links workers through distributed computers is only as productive as the system itself. Software agents are emerging as a way to boost workers' productivity, performing group tasks independently. The authors use a typical business conference as an example to show how graphical models and agent prototyping empower flexible working environments.
Combining pulse compression and adaptive drive signal design to inverse filter the transducer system response and improve resolution in medical ultrasound

An adaptive inverse filtering technique has been incorporated into a medical ultrasound B-scan scheme that used a linear frequency modulated pulse for imaging. Resolution improvement is demonstrated with imaging experiments on wire targets and tissue-mimicking phantoms.
Analyzing the development of an OD practitioner

This article discusses the process of learning to perform organization development (OD) work full time. In studying this the authors conducted a "clinical" analysis ofa journal kept by one of the a...
Definiteness in the Hebrew noun phrase

This paper suggests an analysis of Modern Hebrew noun phrases in the framework of HPSG. It focuses on the peculiar properties of the definite article, including the requirement for definiteness agreement among various elements in the noun phrase, definiteness inheritance in construct-state nominals, the fact that the article does not combine with constructs and the similarities between construct-state nouns and adjectives. Central to our analysis is the assumption that the Hebrew definite article is an affix, rather than a clitic or a stand-alone word. Several arguments, from all levels of linguistic representation, are provided to justify this claim. Adopting the lexical hypothesis, we conclude that the article combines with nominals in the lexicon, and is no longer available for syntactic processes. This leads to an analysis of noun phrases as NPs, rather than as DPs; we show that such a view is compatible with accepted criteria for headedness. We provide an HPSG analysis that covers the above mentioned phenomena, correctly predicting the location of the definite article in constructs, accounting for definiteness agreement and definiteness inheritance constraints, and yielding similar structures for the two major ways of expressing genitive relations in Hebrew.
SITUATING SUGAR STRIKES: CONTESTATIONS OF RACE AND POLITICS IN DECOLONIZING ST. LUCIA

Decolonization in the British West Indies involved tensions over the intersection of nationhood, race, and politics as well as disagreements (across race and class) over the extent to which colonies should extract themselves from ties to the metropole. These issues were evident in an extended 1957 sugar workers' strike in St. Lucia. The event brought predominantly European plantation employers and Afro-St. Lucian middle-class trade unionists and political activists to the negotiating table. Four days of labor talks revealed a layered debate not merely about wages and work conditions on sugar estates. Although not overtly stated, the debate also concerned the process of achieving internal self-government on the island, and negotiating social and geographical boundaries of the emerging nation.
Centre for software reliability

Abstract Electronics has meanwhile become an integral component of safety-related systems located in vehicles or the road side. Particularly in motor vehicles, the overall safety of vehicle sub-systems such as steering, brakes, speed control, seat adjustment etc. is influenced by actively intervening in mechanical hydraulic and pneumatic systems via actuators and other devices. Certain safety requirements must be fulfilled to ensure that electronics does not represent a safety risk. Through the execution of a preliminary hazard analysis an identification of hazardous situations is possible. To graduate these hazardous situations we have 5 controllability categories from uncontrollable to nuisance only, which depends immediately on 5 safety integrity levels. Depending on the safety integrity level, special measures are to be used. There are two main groups of measures, one is measures to avoid faults and on the other hand measures to control faults. It is necessary to use measures from both groups. If this requirement profile is taken into account during development, statutory requirements on safety should be considered as having been fulfilled.
The effect of abrasive particle size on the slurry erosion resistance of particulate-reinforced aluminium alloy

Abstract The slurry erosion behaviour of alumina-particle-reinforced aluminium alloy was investigated for three different ranges of abrasive size: 106, 180—300 and 600 μm. The silica particles content of the slurry was 10 wt.% and the slurry velocity was maintained constant at 15 m s −1 . The reinforcement helps to protect the surrounding matrix in shallow-impingement-angle conditions. For large impact angles the fine particles strongly deviate near the surface while the coarse particles have sufficient energy to cause the breakage of reinforcing particles. These basic mechanisms are discussed in parallel with the predicted trajectories of abrasive particles near the test surface.
KAON DECAYS AND A DETERMINATION OF THE SCALE OF CHIRAL SYMMETRY

Using effective chiral Lagrangians, we consider the occurrence of quadratic terms in the $\ensuremath{\Delta}I=\frac{1}{2}$ $K\ensuremath{\rightarrow}3\ensuremath{\pi}$ matrix element. The inclusion of higher-derivative Lagrangians leads to a significant improvement over the usual current-algebra analysis. This allows an extraction directly from experimental data of ${\ensuremath{\Lambda}}_{\ensuremath{\chi}}$, a measure of the scale of chiral symmetry. We give an operational definition of the chiral scale, and find ${\ensuremath{\Lambda}}_{\ensuremath{\chi}}\ensuremath{\approx}1$ GeV. The issue of uncertainty in the phenomenological determination of the $B$ parameter is clarified.
Microcomputer-Administered Research: A Generalized Basic Subroutine for Administering Likert Items

A generalized BASIC program subroutine is described which may be used by educational researchers who want to collect data by microcomputer by using Likert type items. The subroutine may be easily modified for special purposes and may be employed by investigators for collecting certain types of attitudinal or cognitive data. Versions of the routine that are available for Commodore and Apple computers may be easily modified for use with other microcomputer systems running a Microsoft BASIC.
Enhancement of jejunal absorption of heparinoid by sodium ethylenediaminetetraacetate in the dog.

SummaryThe presence of NaEDTA in the lumen of isolated canine jejunal segments in situ produced significant enhancement of intestinal absorption of heparinoid as measured by the disappearance of heparinoid from the lumen. Increases in clotting time of recalcified citrated plasma accompanied the enhanced absorption and verified that the heparinoid had been absorbed without loss of anticoagulant activity.
Elaborating the Structures of a Science Discipline to Improve Problem-Solving Instruction: An Account of Classical Genetics' Theory Structure, Function, and Development.

Situating the conceptual knowledge of a science discipline in the context of its use in the solving of problems allows students the opportunity to develop: a highly structured and functional understanding of the conceptual structure of the discipline; general and discipline-specific problem-solving strategies and heuristics; and insight into the nature of science as an intellectual activity. In order realize these potential learning outcomes, the reconstructions of scientific theories used in problem solving must provide a detailed account of (1) realistic scientific problems and their solutions; (2) problem-solving strategies and patterns of reasoning of disciplinary experts; (3) the various ways that theories function for both disciplinary experts and students; and (4) the way theories, as solutions to realistic scientific problems, develop over time. The purpose of this paper, therefore, is to provide further specificity regarding a philosophical reconstruction of the structure of Classical Genetics Theory that can facilitate problem-solving instruction. We analyze syntactic, semantic and problem-based accounts of theory structure with respect to the above criteria and develop a reconstruction that incorporates elements from the latter two. We then describe how that reconstruction can facilitate realistic problem solving on the part of students.
Strategic Responses to an Environmental Jolt: Executive Turnover in Internet IPOs

We develop a model that predicts the likelihood that publicly-traded start-up firms will respond to a sudden drop in environmental munificence by replacing their CEO. The model proposes that CEOs who were founders, those who had prior experience as CEOs, and those who also held the position of board chair will be less likely to be replaced. We base these predictions on a set of knowledge-based and political considerations. We test the model on a sample of 127 Internet IPOs during the period following the dramatic devaluation of Internet stocks that occurred in Spring/Summer 2000. Results support all three hypotheses.