cssi/SciSciGPT-SciSciNet huggingface dataset:
Structure and function of Escherichia coli ribosomes: VI. Mechanism of assembly of 30 s ribosomes studied in vitro☆☆☆

Abstract Reconstitution of 30 s ribosomes from 16 s ribosomal RNA and a mixture of 30 s ribosomal proteins was studied. Several factors affecting the efficiency of the reconstitution were examined. It was found that there is a sharp optimum ( I = 0.37) for the ionic strength of the reconstitution mixture. Magnesium ions must be present in the reconstitution mixture at a concentration of 0.01 m or higher (measured up to 0.03 m ). With a 15-minute incubation at 40 °C, the maximum efficiency was obtained at pH values between 6.5 and 8.0 (at 40 °C). The reconstitution reaction was first-order with respect to formation of active 30 s ribosomes. Changes in the total concentration of the reactants do not affect the kinetics of reconstitution, expressed as a percentage of the final value. Thus the rate-limiting reaction is probably unimolecular. The rate of reconstitution is strongly dependent on the temperature of the incubation mixture. From the dependence of the rate constant on temperature, an Arrhenius activation energy of 37.8 kcal./mole has been obtained. Calculation has also given a positive value for the entropy of activation. Incubation of the reconstitution mixture at 0 °C does not produce 30 s ribosomes. The particles (presumed reconstitution intermediates, or RI particles) isolated by centrifugation from such reconstitution mixtures are deficient in several protein components (S proteins), which are recovered from the supernatant fraction after centrifugation. RI particles are functionally inactive. Neither restoration of their functional activity by S proteins nor efficient binding of S proteins to RI particles can take place at 0 °C, but do so only after incubation at higher temperatures. However, heating RI particles alone at 40 °C for 20 minutes produces particles (activated reconstitution intermediates, or RI ∗ particles) which are now capable of binding S proteins at 0 °C and becoming functional 30 s ribosomes. Thus, the reconstitution takes place in step-wise fashion: 16 s RNA → + RI proteins RI particles → heating RI ∗ particles → + S proteins 30 s ribosomes. The reaction RI particles → RI ∗ particles is the ratelimiting unimolecular reaction, representing a structural rearrangement of RI particles which requires high activation energy. Experiments are also described in which formation of functionally active 30 s ribosomes from unfolded 30 s ribosomes was demonstrated. The kinetics of this refolding process under the conditions used has been shown to be almost identical to those of reconstitution of 30 s ribosomes from RNA and proteins. It is shown that the same intermediate, the RI particle, is involved in both reactions.
Molecular dissection of nucleolin’s role in growth and cell proliferation: new insights

Cells require optimum protein synthetic activity in order to support cell proliferation, maintain homeostatic and metabolic integrity, and repair damage. Since growth depends on protein synthesis through ribosome biogenesis, the control of biosynthesis of ribosomes is necessarily a key element for control of growth. Nucleolin is a major nucleolar protein of exponentially growing eukaryotic cells, which is directly involved in the regulation of ribosome biogenesis and maturation. The highly conserved nucleolin contains three major domains through which it controls the organization of nucleolar chromatin, packaging of pre-RNA, rDNA transcription, and ribosome assembly. Numerous reports have implicated the involvement of nucleolin either directly or indirectly in the regulation of cell proliferation and growth, cytokinesis, replication, embryogenesis, and nucleogenesis. Nucleolin, an RNA binding protein, is also an autoantigen, a transcriptional repressor, and a switch region targeting factor. In addition, n...
An ultrafast-ultrafine scanning force photoconductive probe

Road-maps used by the semiconductor industry for device and circuit fabrication in United States and Japan have set targets for 0.1 micron design in general production by the year 2007. The need for increased temporal resolution on nanometric structures has led us to investigate the use of a scanning force microscope (SFM) with the added capability of picosecond-time-resolved waveform measurement. With this tool we are able to measure both nanometer dimensions and picosecond durations using a single probe.
PET IMAGING STUDIES IN DRUG ABUSE RESEARCH.

There is overwhelming evidence that addiction is a disease of the brain (Leshner, 1997). Yet public perception that addiction is a reflection of moral weakness or a lack of willpower persists. The insidious consequence of this perception is that we lose sight of the fact that there are enormous medical consequences of addiction including the fact that a large fraction of the total deaths from cancer and heart disease are caused by smoking addiction. Ironically the medical school that educates physicians in addiction medicine and the cancer hospital that has a smoking cessation clinic are vanishingly rare and efforts at harm reduction are frequently met with a public indignation. Meanwhile the number of people addicted to substances is enormous and increasing particularly the addictions to cigarettes and alcohol. It is particularly tragic that addiction usually begins in adolescence and becomes a chronic relapsing problem and there are basically no completely effective treatments. Clearly we need to understand how drugs of abuse affect the brain and we need to be creative in using this information to develop effective treatments. Imaging technologies have played a major role in the conceptualization of addiction as a disease of the brain (Fowler et al., 1998a; Fowler et al., 1999a). New knowledge has been driven by advances in radiotracer design and chemistry and positron emission tomography (PET) instrumentation and the integration of these scientific tools with the tools of biochemistry, pharmacology and medicine. This topic cuts across the medical specialties of neurology, psychiatry, cancer and heart disease because of the high medical, social and economic toll that drugs of abuse, including and especially the legal drugs, cigarettes and alcohol, take on society. In this chapter we will begin by highlighting the important role that chemistry has played in making it possible to quantitatively image the movement of drugs as well as their effects on the human brain. This will be followed by highlights of PET studies of the acute effects of the psychostimulant drugs cocaine and methylphenidate (ritalin) and studies of the chronic effects of cocaine and of tobacco smoke on the human brain. This chapter concludes with the description of a study which uses brain imaging coupled with a specific pharmacological challenge to address the age-old question of why some people who experiment with drugs become addicted while others do not.
Dynamic performance of embedded HVDC with frequency control strategy

An embedded HVDC system is a HVDC link connected in parallel with an AC transmission line or a mashed AC system. This paper proposes a control strategy cooperating with conventional d-q vector control for embedded HVDC system. The novel control method employs frequency features at two terminal stations to eliminate power oscillation. Dynamic simulation models are constructed in PSCAD platform to compare the transient stability of the proposed strategy with the conventional d-q vector control. According to the simulation results, the average Critical Clearing Time after contingencies is improved by 22.93% when equipped with the proposed frequency control method.
It could be and could have been otherwise: For a non-Euclidean Engagement with Mexico City’s ’68

This article proposes a research design and understanding of context appropriate to a non-Euclidean engagement with a famous massacre in the Mexico City neighborhood Tlatelolco on 2 October 1968. Mexico City’s experience of 1968 is lesser-known than those of many other cities (e.g., Paris). But the predominant narrative of Mexico City’s experience tends to be similar in structure to those of better-known ’68s insofar as Mexico City’s ’68 has been invested with an essential content from which deviations are repelled. Accordingly, Mexico City’s ’68 is regularly treated as if synonymous with ‘Tlatelolco’ – a shorthand both for where and when ’68 took place, and also for an ongoing conflict (alternately a ‘sacrifice,’ or repression by the state), which it is taken to exemplify. This spatial-temporal circumscription and projection of certitude onto the past forecloses ’68’s contemporary political relevance and poses Tlatelolco as its container. But how and to what effect might one restore contingency to Tlatelolco? This article primarily draws from Foucault and Ranciere to suggest that nonEuclidean engagement can denaturalize inherited exclusions from ‘the field,’ establish overlooked connections to its ostensible outsides, and thereby make politics possible.
Large are variability in climate-based soil moisture estimates and implications for remote sensing

Although the basic physical relationships between various remotely sensed signatures and soil are sound, the representativeness of pixel-averaged wetness used to interpret the remotely sensed data is often suspect and at times even doubtful. To study the affect of local variation in soil moisture on the large-area average, mean areal precipitation, temperature and modelled soil moisture in 1/4° grid cells were analyzed for a 700 km by 400 km region in the US Southern Great Plains. Variability in five years of mean daily grid cell data was investigated for 150 km2 study sites, approximately corresponding in size to a satellite microwave pixel. The number of wetted grid cells and the magnitude of precipitation in grid cells within a site were highly variable. The variability of each of these factors is critical, and will not only influence mean site wetness, but also how the area will be seen from space. Analysis indicated that similar mean site precipitation values may result from numerous widely differing combinations of precipitation magnitude and watted gric cell population. Consequently, mean site moisture is also highly variable in the distribution and magnitude of the individual cell moisture values. Extreme values in several grid cells may severely bias the quadrant mean, while influencing a remote measurement much less. Although large-scale surface wetness may eventually be reliably inferred from satellite measurements, a degree of uncertainty will always exist, especially in semi-arid areas. One may be required to associate mean soil moisture with an expected distribution of wetness within a pixel.
Crystal structures of thecis-anti photodimer of uracil

Irradiation of uracil in ice produces a small quantity of thecis-anti cyclobutyl type photodimer. The molecule contains a pseudo two-fold axis and a cyclobutyl ring which is puckered, with dihedral angles near 150°. Torsion angles about the C(5)-C(6′) and C(5′)-C(6) bonds are 21°. Each uracil residue has seven atoms which are coplanar to within 0-07 A, while C(6) and C(6′) are 0·38 A and 0·35 A out of the planes of their respective residues. Each molecule participates in eight NH...O bonds which range from 2·83 to 2·97 A. The material crystallizes in the triclinic space group P¯1 with unit cell parametersa = 8·594 A,b = 7·478 A,c = 6·915 A, α = 96·9 °, β = 95·4 ° and γ = 85·5 °. The structure was solved by means of the symbolic addition procedure for phase determination.
Prediction of New Leads from a Distance Geometry Binding Site Model

Abstract In a previous study, we derived a 9 point model of the binding site of S. faecium dihydrofolate reductase, given only the binding data for a set of 68 quinazoline inhibitors. We have now used this model to search for novel chemical classes of inhibitors with comparable predicted activity, The computer algorithm consults a library of ring systems and other molecular fragments of known structure and fits the most likely of these into the site, making chemical modifications where appro- priate. The search has located diaminopteridines with calculat- ed activity comparable to that of the best quinazolines for which the site was constructed. In addition, the search algo- rithm’s unfettered imagination proposes much more bizarre candidates, such as a benzoxazoline-2-one dimer. Our present purpose is not to claim we have performed an exhaustive search for all possible antifolates, but rather to outline how the calculations are done and to demonstrate that these preliminary results are reasonable.
On proper (popper?) and improper uses of information in epistemology

Expose des differentes theses traitant du role pragmatique de la notion d'information dans un cadre epistemologique: la logique inductive de Carnap, la conception universaliste du langage de Frege, la conception logique des probabilites a priori par Carnap, les probabilites de second-ordre chez Hallden et Popper
The Long-Term Effects of Iridectomy for Primary Acute Angle-Closure Glaucoma

Forty-nine eyes were treated with iridectomy for primary acute angle-closure glaucoma. Forty asymptomatic, normotensive fellow eyes were similarly treated. The duration of follow-up after surgery was 52.3 +/- 3.6 months. Thirty-seven (76%) of the eyes with acute attacks were cured by iridectomy alone and required no medical therapy. Twelve eyes (24%) developed increased intraocular pressure following iridectomy, but only one eye (2%) required filtering surgery. Eighty-eight percent of the asymptomatic, normotensive fellow eyes required no subsequent therapy, and none developed visual field defects. Visual acuity was unchanged in 22 of 49 (45%) of the acutely involved eyes and decreased more than six lines in 11 (22%) eyes. In the 40 fellow eyes, visual acuity was unchanged in 63% and decreased more than six lines in only one (2%) eye.
Deficit in Long-Term Synaptic Plasticity Is Rescued by a Computationally Predicted Stimulus Protocol

Mutations in the gene encoding CREB-binding protein (CBP) cause deficits in long-term plasticity, learning, and memory. Here, long-term synaptic facilitation (LTF) at Aplysia sensorimotor synapses in cell culture was used as a model system to investigate methods for overcoming deficits in LTF produced by a CBP knockdown. Injecting CBP–siRNA into individual sensory neurons reduced CBP levels and impaired LTF produced by a standard protocol of five 5-min pulses of serotonin (5-HT) delivered at 20 min interstimulus intervals. A computational model, which simulated molecular processes underlying LTF induction, predicted a rescue protocol of five pulses of 5-HT at non-uniform interstimulus intervals that overcame the consequences of reduced CBP and restored LTF. These results suggest that complementary empirical and computational studies can identify methods for ameliorating impairments of learning attributable to molecular lesions.
Cinecoronary Arteriography in Young Men

Of a group of 723 men less than 40 years old who underwent cinecoronary arteriography primarily for evaluation of chest pain, 357 (49%) were found to have at least 50% narrowing of one or more coronary arteries. The youngest person was 17 years old. The distribution of lesions in the young men was similar to that found earlier in a study of persons not selected by age. The anterior descending coronary artery was most frequently affected; the right coronary artery was most often totally occluded. No total occlusions of the left main coronary artery were seen. Electrocardiographic evidence of myocardial infarction, found in 109 patients, was less common with disease of the circumflex or right coronary arteries than with disease of the anterior descending coronary artery. This observation was confirmed by examination of left ventriculograms for areas of decreased contractility. Six patients had no significant arterial narrowing. The extent of arterial involvement seemed to be related to the duration of symptoms in patients who had angina pectoris or myocardial infarctions. Clinical diagnoses correlated well with the angiographic findings, particularly in those men considered to be normal and those with typical angina pectoris. Addition of atypical features or prolonged pain decreased the degree of correlation. Only 20% of those with cholesterol levels less than 200 mg/100 ml had significant lesions, whereas 81% with levels more than 275 mg/100 ml had such findings.
Intramural hematomas of the esophagus

Two cases of intramural hematoma of the esophagus with complete resolution following conservative therapy are reported. The radiographic and clinical features of this entity are presented as well as a brief review of the pertinent literature.
Repair of potentially lethal radiation damage in confluent and non-confluent cultures of human hybrid cells.

SummaryThe repair of potentially lethal damage (PLDR) in a gamma-irradiated human hybrid cell line (skin fibroblast × HeLa) and its tumourigenic segregant has been studied as a function of cell density at the time of irradiation and during the post-irradiation repair period. The data show that PLDR occurs in both non-confluent and confluent cultures of both cell lines. Furthermore, there is evidence that the extent of PLDR is dependent on cell density and that cell-cell contact may be an important factor in this regard.
The upturn effect in the non-newtonian intrinsic viscosity of polymer solutions—IV. Influence of solvent viscosity and solute molecular weight in polyisobutylene solutions

Abstract The gradient dependence of intrinsic viscosity of three PIB fractions ( M v = 7·6, 7, and 3·8 × 10 6 ) in polybutene oils L100 (ηs = 5 P) and L50 (ηs = 2·5 P) was investigated and compared with data on polydimethylsiloxane ( M v = 4·6 × 10 6 ) in silicone oil (ηs = 5 P). The initial drop is faster and the upturn effect is less with lower molecular weight fractions. The influence of molecular weight seems to be larger than that of solvent viscosity. The minimum occurs at β0 = 200 ( M v = 7·6 × 10 6 ) and 220 ( M v = 3·8 × 10 6 ); these values are very close to that obtained with polymethylmethacrylate in Aroclor (240) but much larger than that with polydimethylsiloxane in silicone oil (28). The location of the minimum seems to shift to smaller value of β0 with increasing compactness and flexibility of the coil.
Bypass routing: An on-demand local recovery protocol for ad hoc networks

On-demand routing protocols for ad hoc networks reduce the cost of routing in high mobility environments. However, route discovery in on-demand routing is typically performed via network-wide flooding, which consumes a substantial amount of bandwidth. In this paper, we present bypass routing, a local recovery protocol that aims to reduce the frequency of route request floods triggered by broken routes. Specifically, when a broken link is detected, a node patches the affected route using local information, which is acquired on-demand, and thereby bypasses the broken link. We implemented SLR (Source Routing with Local Recovery) as a prototype of our approach. Simulation studies show that SLR achieves efficient and effective local recovery while maintaining acceptable overhead.
Canine electrophysiology of encainide, a new antiarrhythmic drug☆

Abstract Encainide, a new benzanillide derivative with high potency and a good therapeutic/toxic ratio, was evaluated with the use of standard His bundle recording techniques to determine its effects on the cardiac conduction system in closed chest animals. Twenty mongrel dogs weighing 18 to 29 kg were anesthetized with 4 percent chloralose and classified into groups: group 1, a control group and groups 2,3, and 4, which were given 0.3, 0.9 and 2.7 mg/kg body weight, respectively, of encalnide In an intravenous infusion over a 15 minute period. Plasma concentration, blood pressure, surface electrocardiogram and atrlal and His bundle electrograms were recorded before, during and after drug infusion for a total of 120 minutes. Heart rate, A-H and H-V intervals, the QRS complex and Q-Tc interval were measured every 5 minutes during sinus rhythm and with constant atrial pacing. In addition, sinus nodal recovery time and atrial, atrioventrlcular (A-V) nodal and left ventricular refractory periods were measured before and immediately after infusion and every 30 minutes for 2 hours. Peak plasma concentration averaged 450 ng/ml in group 2,1,300 ng/ml in group 3 and 4,000 ng/ml in group 4. Blood pressure was not altered at any dose level throughout the study. The QRS complex and H-V interval were significantly prolonged (P
Female players from margin to centre: female sociality, digital consumer citizenship and reterritorialisations

This article takes into consideration social videogames, such as The Sims and Second Life, starting from the assumption that videogames can have influence outside of cyberspace. How are game characters and genres informed by and at the same time inform female players and their performance of gender. The main question addressed here is: What gendered forms does playing take in such games? Who plays with what assumptions on gender? The cases examined here show that recent female-targeted games encourage roles and activities (shopping, flirting) typically hegemonic when not stereotypical for women. In the light of these considerations, I argue that there are contradictory ways in which gender is deterritorialised and then reterritorialised in the latest games genres. These forms of socialisation games offer creative possibilities to players, even though in practice participation is often reduced to female consumer citizenship that reinforces hegemonic gender assumptions.
Hume, Goodman and radical inductive skepticism

Goodman concurs in Hume’s contention that no theory has any probability relative to any set of data, and offers two accounts, compatible with that contention, of how some inductive inferences are nevertheless justified. The first, framed in terms of rules of inductive inference, is well known, significantly flawed, and enmeshed in Goodman’s unfortunate entrenchment theory and view of the mind as hypothesizing at random. The second, framed in terms of characteristics of inferred theories rather than rules of inference, is less well known, but provides a compelling view of inductive justification. Once the two accounts are clearly delineated, one can see that both are driven by a single deep conviction: that inductive justification can only be understood in terms of our actual inductive practice.
Characteristics of Steam Injection Heating. II. Downstream Temperature Variations Within Fluid Stream After Steam Injection

Summary Five steam injectors were tested to determine the extent of high-frequency temperature variations in the fluid downstream from the point of steam injection. The injectors were of three basic design types: tangential, venturi, and nozzle. They were tested with water and, in addition, two were tested with whole milk. The magnitude and period of temperature fluctuations were obtained with a thin-film platinum resistance thermometer. The variations were recorded on 35 mm film from a temperature trace displayed on a high-gain oscilloscope. Periodic temperature variations occurred in the downstream holding sections of steam injection heaters and varied with the type of injector. A tangential injector with a single steam port showed the most downstream temperature variation with water. The venturi design showed the least variation. Temperature fluctuations within the fluid stream decreased rapidly along the downstream holding sections and were nearly constant at approximately 20 in. from the point of steam injections. Whole milk showed lower temperature variations than water.
Restoration of beating and enzymatic response of cultured rat heart cells to cortisol acetate

Abstract Cultures of rat heart cells grown on normal growth medium stop beating after a period of a week to 20 days. Supplementing the growth medium with Cortisol acetate (2.2 mg/100 ml) induces beating and results in a decreased protein concentration. The hexose monophosphate shunt pathway becomes increasingly active in non-beating cells as shown by the increase in the activity of glucose-6-phosphate dehydrogenase; after beating ceases and upon restimulation of beating with cortisol acetate this trend is reversed, the activity decreases and reaches a constant value. At the same time the activities of malic and isocitric dehydrogenases decrease when beating stops; however they increase when beating is restored by cortisol acetate. The possibility of cortisol acetate making available metabolites that would activate the enzymes is suggested.
Toward Intelligent Fault Detection in Turbine Blades: Variational Vibration Models of Damaged Pinned-Pinned Beams

Inaccuracies in the modeling assumptions about the distributional characteristics of the monitored signatures have been shown to cause frequent false positives in vehicle monitoring systems for high-risk aerospace applications. To enable the development of robust fault detection methods, this work explores the deterministic as well as variational characteristics of failure signatures. Specifically, we explore the combined impact of crack damage and manufacturing variation on the vibrational characteristics of turbine blades modeled as pinned-pinned beams. The changes in the transverse vibration and associated eigenfrequencies of the beams are considered. Specifically, a complete variational beam vibration model is developed and presented that allows variations in geometry and material properties to be considered, with and without crack damage. To simplify variational simulation, separation of variables is used for fast simulations. This formulation is presented in detail. To establish a baseline of the effect of geometric variations on the system vibrational response, a complete numerical example is presented that includes damaged beams of ideal geometry and damaged beams with geometric variation. It is shown that changes in fault detection monitoring signals caused by geometric variation are small with those caused by damage and impending failure. Also, when combined, the impact of geometric variation and damage appear to be independent.
Radiation therapy for giant cell tumor of bone.

Abstract Purpose: Giant cell tumor of bone is usually treated with surgical curettage. For recurrent tumors, tumors that are inoperable because of location, and tumors that would require amputation or another radical procedure limiting function, does radiotherapy provide an alternative for local control? Methods and Materials: Sixteen patients with histologically confirmed, giant cell tumor of bone were treated at the University of Florida with irradiation between March 1973 and September 1988. Minimum follow-up was 32 months; 63% of the patients had follow-up for at least 5 years, 44% for greater than 10 years. All sites received doses of 35 Gy or more, and all were treated with megavoltage irradiation. Results: In 12 (75%) of 16 patients, the tumor was controlled locally with irradiation. The four failures occurred at 8, 13, 13, and 25 months following initiation of treatment. Surgical salvage was successful in all four failures for an overall local control rate of 100%. One patient developed pulmonary metastasis 1 month after surgical salvage and is alive without evidence of disease after multiple courses of chemotherapy, surgical resection, and whole-lung irradiation. All patients tolerated the treatment well with no severe or chronic complications. No secondary soft-tissue sarcomas have occurred within the irradiated areas. Conclusion: Giant cell tumor of bone is not a radioresistant tumor as once believed, and complications seen with modern treatment regimens are minor.
DO STANDARDIZED MULTIPLE-CHOICE TESTS PENALIZE DEEP-THINKING OR CREATIVE STUDENTS?

The objective of the study reported here was to explore the relationship of Graduate Record Examinations® (GRE®) General Test scores to selected personality traits—conscientiousness, rationality, ingenuity, quickness, creativity, and depth. A sample of 342 GRE test takers completed short personality inventory scales for each trait. Analyses revealed statistically significant, but slight (positive) correlations of GRE verbal, quantitative, and analytical scores with both creativity and quickness. (Quickness was defined here by, for instance, the ability to handle a lot of information and the ability to understand things.) The results also revealed significant, but very slight (negative) correlations of GRE scores with conscientiousness.
13C NMR SPECTROSCOPY OF PYRROLIZIDINE ALKALOIDS

Abstract The 13 C NMR spectra of nine pyrrolizidine alkaloids of the macrocyclic diester type, seven of the corresponding N -oxides and of the parent base retronecine have been recorded and the signals assigned. The 13 C NMR signals were found to be sensitive to structural variation in both the diester moiety and the heterocyclic ring system, providing useful information for structural elucidation, particularly when the 1 H NMR spectra may be difficult to interpret.
Material characterization and computer model simulation of low density polyurethane foam used in a rodent traumatic brain injury model

Computer models of the head can be used to simulate the events associated with traumatic brain injury (TBI) and quantify biomechanical response within the brain. Marmarou's impact acceleration rodent model is a widely used experimental model of TBI mirroring axonal pathology in humans. The mechanical properties of the low density polyurethane (PU) foam, an essential piece of energy management used in Marmarou's impact device, has not been fully characterized. The foam used in Marmarou's device was tested at seven strain rates ranging from quasi-static to dynamic (0.014-42.86 s⁻¹) to quantify the stress-strain relationships in compression. Recovery rate of the foam after cyclic compression was also determined through the periods of recovery up to three weeks. The experimentally determined stress-strain curves were incorporated into a material model in an explicit Finite Element (FE) solver to validate the strain rate dependency of the FE foam model. Compression test results have shown that the foam used in the rodent impact acceleration model is strain rate dependent. The foam has been found to be reusable for multiple impacts. However the stress resistance of used foam is reduced to 70% of the new foam. The FU_CHANG_FOAM material model in an FE solver has been found to be adequate to simulate this rate sensitive foam.
Generating Automated Text Complexity Classifications That Are Aligned with Targeted Text Complexity Standards

The Common Core Standards call for students to be exposed to a much greater level of text complexity than has been the norm in schools for the past forty years. Textbook publishers, teachers, and assessment developers are being asked to refocus materials and methods to ensure that students are challenged to read texts at steadily increasing complexity levels as they progress through school so that all students remain on track to achieve college and career readiness by the end of 12th grade. Although automated text analysis tools have been proposed as one method for helping educators achieve this goal, research suggests that existing tools are subject to three limitations: inadequate construct coverage; overly narrow criterion variables; and inappropriate treatment of genre effects. Modeling approaches developed to address these limitations are described. Recommended approaches are incorporated into a new text analysis system called SourceRater. Validity analyses implemented on an independent sample of texts suggest that, compared to existing approaches, SourceRater's estimates of text complexity are more reflective of the complexity classifications given in the new Standards. Implications for the development of learning progressions designed to help educators organize curriculum, instruction and assessment in reading are discussed.
A modelling study of processes regulating plankton standing stock and production in the open Subarctic Pacific Ocean

Abstract At Ocean Station P (50°N 145°W) in the open subarctic Pacific Ocean recent estimates of phytoplankton production rate were consistently much higher than those obtained during previous decades of weathership operations. Moreover, the production was supported to a major extent by regenerated forms of nitrogen despite high concentrations of NO 3 . An ecosystem process model, simulating the interactions among phytoplankton, herbivorous microzooplankton and nutrients, was used to evaluate the possible mechanisms underlying both the high production rates and the patterns of utilization of dissolved nitrogenous nutrients. The model results suggest that at Station P the phytoplankton have specific growth rates expected for the ambient light and temperature regime, and furthermore that two processes, grazing control of phytoplankton stock and preferential utilization of NH 4 by the phytoplankton, can account for the continuously low standing stock of phytoplankton and the underutilization of NO 3 in the surface layer in summer. However, moderate limitation of phytoplankton specific growth rate by a trace nutrient such as dissolved iron cannot be ruled out. Winter observations of plankton dynamics at Station P would afford a strong test of the model predictions. In addition, the model highlights several properties of the subarctic Pacific epipelagic ecosystem in need of further investigation. These include possible trace nutrient limitation of maximum specific growth rate of the phytoplankton assemblage; the abundance, types and physiological characteristics of microzooplankton grazers; the sources and intensity of predatory mortality of grazers; effects of daily variability of physical processes on plankton dynamics; and control of growth rates of individual phytoplankton species, especially microphytoplankters whose specific growth rates may be limited by availability of trace nutrients.
Nature of Ferroelectricity in KN O 3

The lattice parameters of KN${\mathrm{O}}_{3}$ were measured in the temperature region of the ferroelectric transition. The changes in the lattice parameters as the crystal undergoes the paraelectric-to-ferroelectric transition have been interpreted as being due to the electrostriction effect. The dielectric constants and losses along the ferroelectric axis have been measured in the audio, megacycle, and microwave frequency regions. The occurrence of a relaxation type of dielectric dispersion in the microwave region, together with the contraction of the ferroelectric axis at the transition, suggests that ferroelectricity in KN${\mathrm{O}}_{3}$ is an order-disorder phennomenon. The observed first-order ferroelectric transition is caused by the large lattice-dipole coupling. A statistical theory based on a double well potential for the nitrate ion and on the assumption of a lattice-dependent internal field explains the origin of the electrostriction effect and the observed anomalies of the ferroelectric transition. The statistical theory is related to Devonshire's thermodynamic theory of the ferro-electric transition, and good agreement is obtained between the theoretically predicted and the experimentally determined coefficients of Devonshire's free energy.
Technology trends in electrophotography

Selected innovations and advances in electrophotographic printing are reviewed. Technological advances in photoreceptors, imaging techniques, toner development and cleaning, fusing, sensors, and new machine configurations and functions are discussed with respect to their possible applicability to future electrophotographic imaging systems. In general, improvements in print quality and reliability remain the main goals. In specific applications, added functions and an increased range of usable media are highly desired.
Why pick on teeth

In the evolution of oral hygiene practices, the toothpick is the progenitor device. Although modern variations are used interdentally, with the current emphasis on plaque control rather than gingival massage and stimulation, the toothpick has been largely superseded by floss, interproximal brushes, and other supplementary aids. The natural hard bristle toothbrush and vigorous scrub brushing popular a generation ago have been replaced by soft bristle nylon brushes and gentler, more defined brushing procedures for plaque removal in the crevicular areas. Quantitative studies support the superiority of the current techniques in maintaining periodontal health with less trauma to the oral tissues.
Fast CP violation

B flavor tagging will be extensively studied at the asymmetric B factories due to its importance in CP asymmetry measurements. The primary tagging modes are the semileptonic decays of the b (lepton tag), or the hadronic b → c(→ s) decays (kaon tag). We suggest that looking for time dependent CP asymmetries in events where one B is tagged leptonically and the other one is tagged with a kaon could result in an early detection of CP violation. Although in the standard model these asymmetries are expected to be small, 1%, they could be measured with about the same amount of data as in the "gold-plated" decay B_d→ψ K_s. In the presence of physics beyond the standard model, these asymmetries could be as large as 5%, and the first CP violation signal in the B system may show up in these events. We give explicit examples of new physics scenarios where this occurs. [S0556-2821(98)09321-7]
On the Characterization of Thermal-Conductivity Degradation During Torsional Fatigue

The thermal conductivity of a metal, subjected to cyclic loading, changes as it degrades due to the appearance of micro-cracks and micro-voids. This continues up to the critical stage where macro-cracks are created and failure occurs. In this study, a theoretical model for thermal-conductivity deterioration is presented that accounts for the cyclic loading. To examine the validity of the results obtained from a theoretical model, an apparatus is designed to measure thermal-conductivity degradation by means of the guarded-comparative-longitudinal heat-flow technique. Results of a series of thermal-conductivity measurements at several stages of torsional fatigue tests are presented. It is shown that the thermal conductivity of Al 6061-T6 decreases approximately 8 % to 12 % before complete failure takes place.
High-power free-electron laser concepts and problems

Free-electron lasers (FELs) have long been thought to offer the potential of high average power operation. That potential exists because of several unique properties of FELs, such as the removal of `waste heat' at the velocity of light, the `laser medium' (the electron beam) is impervious to damage by very high optical intensities, and the technology of generating very high average power relativistic electron beams. In particular, if one can build a laser with a power extraction efficiency (eta) which is driven by an electron beam of average power PEB, one expects a laser output power of PL equals (eta) PEB. One approach to FEL devices with large values of (eta) (in excess of 10%) is to use a `tapered' (or nonuniform) wiggler. This approach was followed at several laboratories during the FEL development program for the Strategic Defense Initiative (SDI) project. In this paper, we review some concepts and technical requirements for high-power tapered-wiggler FELs driven by radio- frequency linear accelerators (rf-linacs) which were developed during the SDI project. Contributions from three quite different technologies--rf-accelerators, optics, and magnets--are needed to construct and operate an FEL oscillator. The particular requirements on these technologies for a high-power FEL were far beyond the state of the art in those areas when the SDI project started, so significant advances had to be made before a working device could be constructed. Many of those requirements were not clearly understood when the project started, but were developed during the course of the experimental and theoretical research for the project. This information can be useful in planning future high-power FEL projects.© (1995) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Advising roles of a computer consultant

Several hours of advisory protocols from a consultant for Personal Computing were taped and analysed in terms of the role which the advisor played in the interaction. The advisor's role was determined by the user's initial approach and the advisor's perception of the needs of the user: informing the user about available information, defining terms or procedures, indexing into appropriate solution sources or methods for more complex problems or structuring a nebulous or poorly understood problem. A taxonomy of stages of information exchange is outlined and the patterns of alternation within each advisor role is described. We suggest implications of this study for the design of advisory systems.
Characteristics of lower-hybrid-wave-driven steady-state tokamak power reactors

The use of lower hybrid waves for current drive in steady-state tokamak power reactors is studied. Constraints imposed by RF wave propagation are considered. The effect of decoupling of electron and ion temperatures is studied and is found to enhance the ratio of fusion power to dissipated power. Tradeoffs for parameters of RF-driven steady-state reactors are determined. It is found that RF-driven steady-state current operation is especially suitable for high-field high-density reactor designs. For example, this study indicates that a tokamak power reactor characterized by a major radius of 6 m, a magnetic field on axis of 7.5 T, and a fusion power output of 2500 MW could be driven in steady-state operation with RF power level equal to 2.5% of the fusion power output.
Pulsed-laser-deposited amorphous diamond and related materials: synthesis, characterization, and field emission properties

Amorphous carbon films with variable sp{sup 3} content were produced by ArF (193nm) pulsed laser deposition. An in-situ ion probe was used to measure kinetic energy of C{sup +} ions. In contrast to measurements made as a function of laser fluence, ion probe measurements of kinetic energy are a convenient as well as more accurate and fundamental method for monitoring deposition conditions, with the advantage of being readily transferable for inter-laboratory comparisons. Electron energy loss spectroscopy (EELS) and spectroscopic ellipsometry measurements reveal that tetrahedral amorphous carbon (ta-C) films with the most diamond-like properties are obtained at the C ion kinetic energy of {approximately}90 eV. Film properties are uniform within a 12-15{degree} angle from the plume centerline. Tapping-mode atomic force microscope measurements show that films deposited at near-optimum kinetic energy are extremely smooth, with rms roughness of only {approximately} 1 {angstrom} over distances of several hundred nm. Field emission (FE) measurements show that ta-C does not appear to be a good electron emitter. After conditioning of ta-C films deposited on n-type Si a rather high turn-on voltage of {approximately}50 V/{micro}m was required to draw current of {approximately}1 nA to the probe. The emission was unstable and typically ceased after a few minutes of operation. The FE tests of ta-C and other materials strongly suggest that surface morphology plays a dominant role in the FE process, in agreement with conventional Fowler-Nordheim theory.
A deeper understanding of heat checking, an old but frequently overlooked failure mechanism, of downhole drilling components

Heat checking, a quench cracking phenomena, is an old but often overlooked failure mechanism of downhole drilling assemblies such as drill collars, drill pipes, heavy weight drill pipes, cross-overs, drilling jars, hardfacings, etc. Heat checking occurs when low alloy steels which have been heated by friction against formation (side load) is rapidly quenched by cool drilling fluids. The susceptibility of drilling assemblies to heat checking increases as drilling practice becomes aggressive. The time has come to properly define heat checking and to develop an in-depth understanding of this phenomena. It has often been misquoted, misunderstood and overlooked among drillers. Heat checking promotes macro- and micro-cracks, mictrostructural changes, hardness changes, iron-oxide formation, or structural changes. To mitigate heat checking-related failure, more in-depth understanding is thus required from metallurgical engineering, mud engineering and environmentally-assisted cracking standpoints. In short, heat checking is a more than one-dimensional problem of quench cracking or drilling operations but involves multi- disciplines.
Regulation of acetylcholine receptors in the mouse muscle cell line, C2.

Abstract The effects of culture age, muscle activity, and cell fusion on the metabolism of acetylcholine receptors in the mouse muscle cell line, C 2 , were determined. Receptor degradation followed complex kinetics and was dependent on culture age. One or two day old myotubes degraded receptors rapidly ( t 50 = 7–8 h) in a nearly single exponential process. Four or five day old myotubes, however, degraded receptors more slowly ( t 50 = 12–16 h) in a process that deviated substantially from single exponential kinetics. A similar complex pattern of receptor degradation was seen with the L 6 cell line, but receptor degradation followed single exponential kinetics and was independent of culture age in primary rat myotubes and the BC3H-1 cell line. Acetylcholine receptors on C 2 myotubes were immunologically similar to the extrajunctional receptors of denervated mouse muscle. Clustered receptors were degraded at approximately the same rate as the total receptor population and receptor turnover was not changed when spontaneous contractions of the C 2 myotubes were inhibited. Newly synthesized receptors were more rapidly degraded than older receptors. Finally, receptors on fusion-arrested C 2 myoblasts were degraded at the same rate ( t 50 = 16 h) regardless of culture age.
Effect of wire diameter on the thermosonic bond reliability

Thermosonic bonding process is a viable method to make reliable interconnections between die bond pads and leads using thin gold and copper wires. This paper investigates interface morphology and metallurgical behavior of the bond formed between wire and bond pad metallization for different design and process conditions such as varying wire size and thermal aging periods. Under thermal aging, the fine pitch gold wire ball bonds (0.6 mil and 0.8 mil diameter wires) shows formation of voids apart from intermetallic compound growth. While, with 1-mil and 2-mil diameter gold wire bonds the void growth is less significant and reveal fine voids. Studies also showed void formation is absent in the case of thicker 3 mil wire bonds. Similar tests on copper ball bonds shows good diffusional bonding without any intermetallic phase formation (or with considerable slow growth) as well as any voids on the microscopic scale and thus exhibits to be a better design alternative for elevated temperature conditions.