cssi/SciSciGPT-SciSciNet huggingface dataset:
Solar-thermal production of graphitic carbon and hydrogen via methane decomposition

This work reports a process in which concentrated irradiation from a simulated solar source converts methane to high-value graphitic carbon and hydrogen gas. Methane flows within a photo-thermal reactor through the pores of a thin substrate irradiated by several thousand suns at the focal peak. The methane decomposes primarily into hydrogen while depositing highly graphitic carbon that grows conformally over ligaments in the porous substrate. The localized solar heating of the porous substrate serves to capture the solid carbon into a readily extractable and useful form while maintaining active deposition site density with persistent catalytic activity. Results indicate a strong temperature dependence with high decomposition occurring in the central heating zone with concentration factors and temperatures above 1000 suns and 1300 K, respectively. Even with a large flow area through regions of lower irradiation and temperature, methane conversion and hydrogen yields of approx. 70\% are achieved, and 58\% of the inlet carbon is captured in graphitic form.
Traffic Sign Detection and Identification

Previous studies using eye-trackers have suggested that drivers can extract information from traffic signs and markings without fixating them. The first study reported here examined the angle of gaze away from signs that enables sign detection: detection conspicuity angle. A second study examined the angle of gaze away from signs that enables identification of the signs’ messages: identification conspicuity angle. Because conspicuity is viewed as a product of the properties of objects and their surrounding environment, both studies manipulated the background of the signs. Detection conspicuity was sensitive to the background environment, particularly for regulatory signs, for which detection conspicuity was reduced with light-colored or cluttered backgrounds. Background environment had little measureable effect on sign message identification. It is recommended that sign backgrounds be considered when locating signs, and that if the background does not provide adequate contrast, conspicuity enhancement strategies should be considered.
Mechanisms of Heat Action

In the last two chapters I have portrayed various ways that mildly elevated temperatures modify survival kinetics of mammalian cells. Environmental factors were shown to have considerable influence in determining cell death. Ionizing radiations, as well as many drugs, become more effective in inactivating cells when exposures are carried out at hyperthermic temperatures. Now I will describe some of the known or suspected mechanisms underlying the phenomenological descriptions. Specifically, I will sequentially address the following questions: Are there specific critical “targets,” i.e., subcellular organelles or molecules, that are particularly heat sensitive and hence responsible for cell death? If so, what are these likely to be? What is the cause of thermotolerance? What are the mechanisms of accentuated X-ray cytotoxicity at elevated temperatures? Finally, I will look at some of the mechanisms likely to be responsible for heat-drug interactions.
Calculating web page trustworthiness by exploring communities on the web

With the growth of the Internet and the ease with which websites can be created, a lot of web pages of questionable quality and authority have appeared and it has become a significant problem to search the web for trustworthy information [3]. In addition, more and more Internet users rely on and trust information they receive from the Internet than from any other source [2]. Most people, when doing a web search, only look at the first page of results returned by the search engine. As a result, for a lot of commercial sites it is important to appear as one of the first search results, and pages containing advertisement, propaganda material, or "informercials" try to rank higher. Our goal is to prevent such pages, called spam, from qualifying high in the results returned by web search engines.
Interface kinetics and crystal growth under conditions of constant cooling rate: I. Constant diffusion coefficient

The kinetics of crystal growth are calculated when a crystal seed and its nutrient bath are subjected to a constant and homogeneous cooling programme. We allow for a temperature variation both in the equilibrium concentration Ce and in the interfacial reaction constant k. Departures from Minden's analysis are striking. With time, the growth rate first increases linearly, then decays exponentially. Its behavior is essentially controlled by k. Thus, the thickness of the deposited material reaches a limiting value. In the course of time, the interfacial concentration can deviate from Ce, leading to a high local supersaturation and to the possibility of surface instabilities.
A Semantic and Pragmatic Model of Lexical and Grammatical Aspect

This work studies two related phenomena in human language: the ability of verbs and other lexical items to describe how a situation (event or state) develops or holds in time (sc LEXICAL ASPECT) and the view some verbal auxiliaries and affixes present of the development or result of situations at a given time (sc GRAMMATICAL ASPECT). Through this investigation I reveal a formal situation structure represented by aspectual phenomena, a structure to which other linguistic elements refer, particularly tense. I examine data in a variety of languages, taking particular care to distinguish between aspect semantics and cancellable pragmatic implicatures associated with aspect forms. The semantic-pragmatic distinction provides a tool for determining what properties need to be accounted for in the semantic representation and what may be adduced as evidence for these properties. In particular, I show that oppositions generally assumed to be semantically equipollent ($+/-$) are semantically privative ($+$/unmarked), with unmarked forms interpreted in accordance with pragmatic principles. Lexical aspect semantics is represented by the privative features ($+$telic), ($+$dynamic), and ($+$durative). These features define the Event Time (ET) as a situation structure consisting of a nucleus and a coda. Grammatical aspect oppositions, also represented privatively, crucially interact with this structure: ($+$imperfective) views situations intersecting a Reference Time (RT) at the nucleus, and ($+$perfective) views them at the coda. The conception of grammatical aspect as a view of the ET-RT intersection allows the representation of tense to be limited to a relation between a RT and the deictic center (C). Complex temporal phenomena--"perfect" and "extended" tenses--are shown to be interactions between grammatical aspect and tense. The privative analysis allows aspect semantics to be built up monotonically--from the lexical aspect ET features, the grammatical aspect view of the ET, and tense. The semantics restricts pragmatic interpretation in principled ways, based on marked and unmarked features. Chapter 1 introduces theoretical issues and assumptions. Chapters 2-4 outline the semantic structure of lexical aspect, grammatical aspect, and tense, respectively. Chapters 5-6 apply the analysis to the aspect and tense systems of English and New Testament Koine Greek.
Redundancy identification and removal based on implicit state enumeration

The knowledge of the state transition graph (STG) of a sequential circuit helps in generating test sequences and identifying redundancies. The application of algorithms to the identification and removal of redundancies is reported. This strategy is based on traversing the STG of the given circuit and then performing redundancy identification using the reachability information calculated by the traversal. This method considers one candidate redundancy at a time, in an order that tries to minimize the total processing time. Substantial area and delay reductions are achieved. Experiments show that for many circuits 100% of the sequentially redundant faults can be eliminated in very reasonable amounts of time. >
New ways to learn from the Challenger Disaster: Almost 30 years later

As we approach the thirtieth anniversary of the Challenger Disaster (January 28, 2016), how do we continue to educate current and future leaders on how to make decisions that involve significant risk and uncertainty with the lessons of Challenger in mind? To address this challenge we have created a case that places decision makers in a situation of risky choice. The case uses but masks the facts of the Challenger launch decision in the premise of a Coast Guard response to a wrecked cruise ship that is leaking oil. The protagonist in the case, Captain Bob Ross, a Coast Guard pilot, has to decide whether or not to send immediately the one Hercules aircraft he has available to move the oil-pollution equipment. Captain Ross faces pressure to send the flight and uncertainty regarding recent engine problems that may or may not be temperature related. We collected decision responses from participants for multiple versions of the case to see how different pieces of additional information can influence decisions. We demonstrate that both additional information regarding the worst case consequences and additional information regarding the relationship between temperature and seal failure will make decision makers less likely to send the flight. While these conditions are less likely than the base-case description, less likely is still high as around 70% (depending on condition) send the flight even with additional information. For the base-case description, 83.5% sent the flight. We conclude with discussion of the insights for organizational learning that can be gained from a case discussion of a decision similar to that faced by the Challenger managers but in a context different than Challenger.
Acoustic backscattering from cylinders: near-field corrections

In the course of making TS (target strength) measurements of hollow aluminum cylinders of length 91 cm and 28 cm in the frequency range 30-36 kHz, the authors realized that their measurements were being corrupted at beam aspect because the source and receiver were in the near-field of the target. Fortunately, they were able to increase the range and reduce this effect, but they also derived a correction to the near-field TS measurements that could be applied if sufficient range were unavailable. The derivation and application of this beam-aspect TS correction is the subject of the present work
Biodurability of single-walled carbon nanotubes depends on surface functionalization

Recent research has led to increased concern about the potential adverse human health impacts of carbon nanotubes, and further work is needed to better characterize those risks and develop risk management strategies. One of the most important determinants of the chronic pathogenic potential of a respirable fiber is its biological durability, which affects the long-term dose retained in the lungs, or biopersistence. The present article characterizes the biodurability of single-walled carbon nanotubes using an in vitro assay simulating the phagolysosome. Biodurability is observed to depend on the chemistry of nanotube surface functionalization. Single-walled nanotubes with carboxylated surfaces are unique in their ability to undergo 90-day degradation in a phagolysosomal simulant leading to length reduction and accumulation of ultrafine solid carbonaceous debris. Unmodified, ozone-treated, and aryl-sulfonated tubes do not degrade under these conditions. We attribute the difference to the unique chemistry of acid carboxylation, which not only introduces COOH surface groups, but also causes collateral damage to the tubular graphenic backbone in the form of neighboring active sites that provide points of attack for further oxidative degradation. These results suggest the strategic use of surface carboxylation in nanotube applications where biodegradation may improve safety or add function.
Maternal age, multiple birth, and extremely low birth weight infants.

Objectives To compare the rates of adverse neurodevelopmental outcome or death at 18 to 22 months among extremely low birth weight (ELBW) infants born to mothers ≥40 years to the corresponding rates among infants of younger mothers. Study design Prospective evaluation of ELBW infants to quantify the relative risks of maternal age and multiple birth for death or adverse neurodevelopmental outcome. Results The sample consisted of 14 671 live ELBW births divided into maternal age groups: Conclusion Although mothers ≥40 years had high pregnancy-related morbidities, we found no overall increased risk of the composite outcome of death or NDI. Multiple birth, however, was a predictor of all adverse outcomes examined, regardless of maternal age.
The bovine peripheral-type benzodiazepine receptor: a receptor with low affinity for benzodiazepines.

Abstract The density of bovine peripheral-type benzodiazepine receptors (PBR) in four tissues was highest in adrenal cortex. The adrenal cortex PBR cofractionated with a mitochondrial membrane marker enzyme and could be solubilized with intact ligand binding properties usin3 digitonin. The membrane bound and soluble mitochondrial receptors were pharmacologically characterized and showed the rank order of potency to inhibit [ 3 H]PK 11195 binding was PK 11195 > protoporphyrin IX > benzodiazepines (clonazepam, diazepam, or Ro5-4864). [ 3 H]PK 11195 binding to bovine adrenal mitochondria was unaffected by diethylpyrocarbonate, a histidine residue modifying reagent that decreased binding to rat liver mitochondria by 70%. [ 3 H]PK 14105 photolabeled the bovine PBR and the Mr was estimated under nondenaturing (200 kDa) and denaturing (17 kDa) conditions. These results demonstrate the bovine peripheral-type benzodiazepine receptor is pharmacologically and biochemically distinct from the rat receptor, but the receptor component photolabeled by an isoquinoline ligand has a similar molecular weight.
An extension of Karmarkar's algorithm for linear programming using dual variables

We describe an extension of Karmarkar's algorithm for linear programming that handles problems with unknown optimal value and generates primal and dual solutions with objective values converging to the common optimal primal and dual value. We also describe an implementation for the dense case and show how extreme point solutions can be obtained naturally, with little extra computation.
Long-term wavelength stabilization of a commercial pulsed dye laser.

An inexpensive device is described that stabilizes the wavelength of a commercial nanosecond-pulsed dye laser. The instrument monitors the frequency-dependent interference pattern that is generated when a portion of the dye laser output passes through an external Fabry–Perot etalon. In order to maintain a fixed wavelength, a personal computer adjusts the dye laser’s grating position when the interference pattern indicates that a shift in laser wavelength has occurred. Tests indicate that this device reduces the drift of the laser’s mean wavelength to < 0.0001-nm/°C ambient temperature change. The feedback mechanism incorporated in this design can sustain stationary frequency stabilization for indefinite periods of time.
Microtubules and Actin Microfilaments Regulate Lipid Raft/Caveolae Localization of Adenylyl Cyclase Signaling Components *

Microtubules and actin filaments regulate plasma membrane topography, but their role in compartmentation of caveolae-resident signaling components, in particular G protein-coupled receptors (GPCR) and their stimulation of cAMP production, has not been defined. We hypothesized that the microtubular and actin cytoskeletons influence the expression and function of lipid rafts/caveolae, thereby regulating the distribution of GPCR signaling components that promote cAMP formation. Depolymerization of microtubules with colchicine (Colch) or actin microfilaments with cytochalasin D (CD) dramatically reduced the amount of caveolin-3 in buoyant (sucrose density) fractions of adult rat cardiac myocytes. Colch or CD treatment led to the exclusion of caveolin-1, caveolin-2, β1-adrenergic receptors (β1-AR), β2-AR, Gαs, and adenylyl cyclase (AC)5/6 from buoyant fractions, decreasing AC5/6 and tyrosine-phosphorylated caveolin-1 in caveolin-1 immunoprecipitates but in parallel increased isoproterenol (β-AR agonist)-stimulated cAMP production. Incubation with Colch decreased co-localization (by immunofluorescence microscopy) of caveolin-3 and α-tubulin; both Colch and CD decreased co-localization of caveolin-3 and filamin (an F-actin cross-linking protein), decreased phosphorylation of caveolin-1, Src, and p38 MAPK, and reduced the number of caveolae/μm of sarcolemma (determined by electron microscopy). Treatment of S49 T-lymphoma cells (which possess lipid rafts but lack caveolae) with CD or Colch redistributed a lipid raft marker (linker for activation of T cells (LAT)) and Gαs from lipid raft domains. We conclude that microtubules and actin filaments restrict cAMP formation by regulating the localization and interaction of GPCR-Gs-AC in lipid rafts/caveolae.
Excitation mechanisms of the electron-beam-pumped atomic xenon (5d→6p) laser in Ar/Xe mixtures

The atomic xenon laser operates on seven infrared transitions (1.73–3.51 μm) between the 5d and 6p manifolds. Intrinsic laser power efficiencies exceeding 5% have been previously obtained in Ar/Xe mixtures, principally at 1.73 μm (5d[3/2]1→6p[5/2]2). The kinetic mechanisms responsible for this performance, though, are not well understood. In this paper, we report on a computer model for the electron‐beam‐pumped xenon laser in Ar/Xe mixtures with which we have investigated some of these excitation mechanisms. Based on the results of a parametric study of power deposition (50 W cm−3 to 100 kW cm−3), gas pressure (0.5–6 atm), and xenon fraction, we suggest that the high efficiency obtained in Ar/Xe mixtures is due to rapid collisional cascade to the upper laser level of the 1.73‐μm transition following dissociative recombination of ArXe+ and selective quenching of the lower laser level of the 1.73‐μm transition by collisions with argon. The results of our model indicate that the decrease in laser performance...
Occurrence of Abscisic Acid in the Gibberellin-Inhibitor from Limabeans

Extracts of immature limabeans, which reduce the gibberellinpromoted growth of red-light-grown dwarf peas, contain abscisic acid (ABA). This was demonstrated by thin-layer chromatography, gas-liquid chromatography and ultraviolet absorption spectra. ABA accounts for more than 50% of the inhibitory activity of the extract.
Using moment invariants to analyze cluster shapes and hypothesize potential causes

Although there are many algorithms and statistical tests to detect clustering of geographical phenomena, such as disease cases, the follow-up task of analyzing the cluster to explain its existence and mitigate the cluster is generally left to the researcher. These cluster detection methods are useful only for part of the process of identifying, understanding, and mitigating disease clusters. This research develops and presents a computer program that uses the information about the shape of the cluster to evaluate the hypotheses about potential causes. To achieve this, the shapes of the clusters are represented by image moment invariant statistics developed in the field of computer vision, and these shape statistics are compared against a database of moment invariants of shapes representative of several geographical processes, such as diffusion along roads and wind diffusion. Experiments using simulated data of different types of disease transmission were carried out, and the ability of the program to accurately classify the different types of diffusion demonstrates the viability of this approach to automated cluster analysis.
Random Vibration of a Beam with a Stick-slip End Condition

Abstract An analysis is presented of the response of a randomly excited beam with an axial stick-slip end condition. The emphasis of the present effort is on the case in which slipping is a relatively rare event so that, while it does not contribute significantly to the system damping, it does have a marked influence on the non-linear behaviour. A simple approximate analysis is developed to estimate the rate at which slipping will occur in a randomly excited beam. This facilitates the construction of guidelines for designing a clamping fixture for a given beam so that slipping occurs infrequently. Comparisons of approximate estimates of the slipping rate with those obtained by numerical simulations show that the approximate method leads to conservative estimates.
Inter- and intraspecific variation in gorgonian colony morphology: quantifying branching patterns in arborescent animals

Geomorphological methods for quantifying branching networks are used to describe inter- and intra-specific differences in branching patterns among two species of arborescent Caribbean gorgonian, Plexaura homomalla, P. flexuosa, and a third, undescribed plexaurid from the San Blas Islands, Panama. There were significant differences among species for first, second and third order branch lengths, and for tributary to source ratios for first and second order branches. Extrapolations from the branching parameters successfully predicted differences in the branch structure of naturally generated colony fragments. Within P. homomalla, significant differences with depth in the lengths and tributary to source ratios of first, second, and third order branches provide a measure of the greater bushiness of shallow water colonies. These measures can be used to quantify morphological differences in both ecological and systematic analyses. Data on the branching characters of these three gorgonian species demonstrate that gross colony form can be studied as a quantifiable component of phenotype and that gorgonians display both species level and ecophenotypic variation in colony form.
Plasma enterolactone and breast cancer risk in the Nurses’ Health Study II

Lignans are plant-based phytoestrogens with both estrogenic and anti-estrogenic properties that may be important for breast carcinogenesis. Retrospective studies have observed decreased breast cancer risk associated with high circulating enterolactone concentrations, a biomarker of lignan intake, but results from prospective studies are conflicting. To prospectively examine this association, we measured plasma enterolactone levels in 802 breast cancer cases and 802 matched controls nested among predominantly premenopausal women in the Nurses’ Health Study II cohort. We used conditional logistic regression and polytomous logistic regression models, adjusting for known breast cancer risk factors, to calculate relative risks (RR) and 95 % confidence intervals (CI). Compared to women with enterolactone concentrations ≤4 nmol/L, the multivariate-adjusted RRs for breast cancer were 1.18 (95 % CI 0.86–1.62), 0.91 (95 % CI 0.66–1.25), and 0.96 (95 % CI 0.70–1.33) for women with enterolactone levels in the second to the fourth quartiles, respectively; P trend = 0.60. Results were similar across tumors defined by estrogen and progesterone receptor status. Among premenopausal women with follicular estradiol levels below the median (<47 pg/mL), women in the highest category of enterolactone levels had a 51 % lower breast cancer risk compared to those in the lowest category (95 % CI 0.27–0.91); P trend = 0.02. No association was observed among women with high-follicular estradiol levels (≥47 pg/mL), (comparable RR = 1.39, 95 % CI 0.73–2.65; P interaction = 0.02). We did not observe an overall association between plasma enterolactone and breast cancer risk in a large nested case–control study of US women. However, a significant inverse association was observed among premenopausal women with low-follicular estradiol levels, suggesting that enterolactone may be important in a low-estrogen environment. This should be confirmed in future studies.
American Identity and the Politics of Ethnic Change

This article explores the way subjective conceptions of national identity influence the mass public's reactions to the changing ethnic composition of American society. Using the symbolic politics model of opinion formation to analyze survey data collected in early 1988, the article demonstrates that normative beliefs about Americanism strongly influence general attitudes toward cultural minorities and, when the appropriate symbolic cues are present, policy preferences on ethnic issues.
THE EFFECT OF MULTIPLE RESPONSES AND CERTAINTY ESTIMATES ON THE INTEGRATION OF VISUAL INFORMATION.

Integration of information was investigated in two experiments that employed a multiple-observation, tilt-discrimination task. The integration model of signal-detection theory generally overestimated the improvement in discrimination resulting front additional observations. Further, probabilistic multiple responses appeared detrimental to discrimination. These results differ from earlier findings using different discrimination tasks. Reasons for the differences were discussed in terms of within-trial redundance and interference caused by complex response modes.
Origami-Based Self-Folding Structure Fabrication Based on 3D Printing on Polystyrene Films

Self-folding structures have unique advantages such as reconfiguration capability during their usage. Such advantages can be beneficial for a wide variety of applications including biomedical and electronics products. However, how to fabricate and actuate self-folding structures is still an ongoing research topic. In the paper a simple fabrication approach based on a 3D printing process is presented for the fabrication of self-folding structures that can be actuated using a constrain-based thermo responsive mechanism. A self-folding structure fabricated by our method is an origami sheet with multiple layers. The middle layer of the origami sheet is a pre-strained polystyrene film, which can have a large shrinkage when exposing to heat. Both its upper and bottom surfaces are covered with desired patterns in cured plastic resin. A foldable hinge is achieved by using the cured resin to constrain the shrinkage of the film on one side while the other side of the film is exposed to the heating environment. A model of the related folding mechanism is developed. Based on it, a hinge structure design method is presented for a given folding angle. Various experiments are performed to verify the folding control of designed self-folding structures. Possible applications of the developed self-folding structures are also demonstrated and discussed.Copyright © 2014 by ASME
McCollum-Pratt Symposium.

The name of Andre Jagendorf, coauthor (with Howard H. Seliger) of the report on the McCollum-Pratt Symposium on Light and Life [Science 132, 1698 (2 Dec. 1960)1, was omitted from the published paper.
Destruction and recreation of black holes

Even though the existence of the gravitationally collapsed concentrations of matter in space known as ‘black holes’ is accepted at all educational levels in our society, the basis for the black hole concept is really only the result of approximate calculations done over 40 years ago. The concept of the black hole is an esoteric subject, and recently the mathematical and physical frailties of the concept have come to light in an interesting round of theoretical shuffling. The recent activity in theorizing about black holes began about 10 years ago, when Cambridge University mathematican Stephen Hawking calculated that black holes could become unstable by losing mass and thus ‘evaporate.’ Hawking's results were surprisingly well received, considering the lack of theoretical understanding of the relations between quantum mechanics and relativity. (There is no quantized theory of gravitation, even today.) Nonetheless, his semiclassical calculations implied that the rate of ‘evaporation’ of a black hole would be slower than the rate of degradation of the universe. In fact, based on these and other calculations, the British regard Hawking as ‘the nearest thing we have to a new Einstein’ [New Scientist, Oct. 9, 1980]. Within the last few months, Frank Tipler, provocative mathematical physicist at the University of Texas, has reexamined Hawking's calculations [Physical Review Letters, 45, 941, 1980], concluding, in simple terms, (1) that because of possible vital difficulties in the assumptions, the very concept of black holes could be wrong; (2) that Hawkings' evaporation hypothesis is so efficient that a black hole once created must disappear in less than a second; or (3) that he, Tipler, may be wrong. The latter possibility has been the conclusion of physicist James Bardeen of the University of Washington, who calculated that black hole masses do evaporate but they do so according to Hawking's predicted rate and that Tipler's findings cause only a second-order effect on the rate process [Physical Review Letters, 46, 382, 1981].
Plugging the hypervisor abstraction leaks caused by virtual networking

Virtual machines are of very little use if they cannot access the underlying physical network. Virtualizing the network has traditionally been considered a challenge best met by such network-centric measures as VLANs, implemented by switches. We begin by arguing that network virtualization is best done by hypervisors, not switches. We then show that modern hypervisors do a poor job in virtualizing the network, leaking details of the physical network into virtual machines. For example, IP addresses used across the host's physical network, are exposed to guest virtual machines. We then propose a method for plugging the network-related leaks by ensuring that the virtual network traffic is encapsulated inside a host envelope prior to transmission across the underlying physical network. In order to overcome the performance hit related to traffic encapsulation, we analyze the unique case of virtual machine traffic encapsulation, exploring the problems arising from dual networking stacks --- the guest's and the host's. Using a number of simple optimizations, we show how an unmodified guest under the KVM hypervisor can reach throughput of 5.5Gbps for TCP and 6.6Gbps for UDP for encapsulated traffic, compared to 280Mbps and 510Mbps respectively when using the default guest and host networking stacks.
Spinal Deformity in Skeletal Dysplasias

Skeletal dysplasias are commonly accompanied by spinal problems, and spinal deformity physicians must be attuned to skeletal dysplasia. Unfortunately, there are no higher-level studies in spinal treatment of skeletal dysplasias, which makes us reliant on case series and even case reports for most of our knowledge. This article outlines the general issues found in skeletal dysplasias and some principals that can be used in assessing and treating the spinal issues.
An evaluation of the short rod technique to measure the fracture toughness of polymers

The investigation of the fundamental variables which influence the fracture toughness of structural plastics is greatly hampered by a large amount of scatter and uncertainty associated with the fracture toughness measurement. A major part of the problem is due to a lack of adherence to ASTM Standard E399, mainly with regard to the requirement for a fatigue crack. A razor-blade arrested crack, which is often blunted, is common practice in the plastics field. It is also common to ignore size (plane strain) and precise machining requirements. The short rod (SR) method was evaluated as a potentially more precise and simpler fracture toughness measurement. This toughness measurement is made on a slowly moving and presumably sharp crack, and the geometry of the sample enforces plane strain conditions. Toughness measurements on compact tension (CT) specimens via ASTM E399 were performed on one-inch (25 mm) samples of poly(methyl methacrylate) (PMMA), polystyrene (PS), polycarbonate (PC) and polysulphone (PSO). Also, a constant compliance method using a contoured double cantilever beam (CDCB) was used to evaluate the toughness of PS, PC, and PSO, but in general we did not achieve stable crack growth. The used samples were then fabricated into SR specimens and their toughness measured. The CT and CDCB methods agreed with each other for PSO and PC, but for PS the CDCB method gave high values. It is argued that the SR method should be compared to the other methods without using a plasticity correction. Then the SR method agrees well with the CT method for PSO and PS and is 15% higher for PC. The PMMA SR results were invalid. Differences between the methods are explained in terms of crack blunting, rate effects, non-homogeneity, residual stresses and the global nature of the crack front. The SR method has promise for polymer evaluation but more experience and evaluation is needed. The method is unique in the ability to study the effects of thermal history and of the environment on fracture toughness.
MODELING OF COMPETITIVE ADSORPTION OF NITROGEN SPECIES IN HYDRODESULFURIZATION

ABSTRACT Previously, we developed a simple, one-parameter model reproducing the observed inhibiting effect of nitrogen species in the hydrodesulfurization (HDS) of hindered sulfur heterocycles. The model owes its simplicity to some nontrivial assumptions. Here we develop a full model by relaxing these assumptions, which gives a more quantitative picture of how sulfur, nitrogen, and catalyst surface interact on many widely disparate time scales. Computational results build a strong case for the accuracy of the previous one-parameter theory. As such, the theory should be applicable to reaction systems in which catalyst poisoning is driven by nonequilibrium adsorption. Some of the complexities and subtleties in modeling the competitive adsorption effects in distillate HDS are discussed, giving special attention to the design of robust catalyst-deactivation-compensation operating strategies.
AGU launches new E-commerce Web site

During the week of 10 September 2007, AGU unveils a new e-commerce Web site (http://www.aip.org/AGU). The site is an upgraded version of the one that members and nonmembers have used to renew membership or join AGU, subscribe to journals, purchase books, or make a contribution. The new site, which is the result of collaboration between AGU and the American Institute of Physics, is another step in improving service to AGU constituents. Most of the changes being implemented stem from suggestions made by AGU members.
Thermal resistance measurements on monolithic and hybrid Darlington power transistors

A method for measuring the thermal resistance, R θ , of integrated power Darlington transistors is described that is based upon the emitter-only switching technique. It is shown that for specified measurement conditions this method can be used to measure the average thermal resistance, R θ (l+2), of the input and output transistors of the Darlington pair and is therefore applicable to production-line monitoring of the thermal characteristics of the Darlington. It is shown that although a direct measurement of the thermal resistance, R θ (2), of the output transistor cannot be made for most Darlingtons, an indirect determination of R θ(2) can be made using the emitter-only switching technique and a simple equation. Comparisons of the differences between the infrared-determined thermal resistance and the electrically-measured thermal resistance of Darlingtons and of discrete power transistors illustrate that the accuracy of the Darlington measurements is comparable with that achievable for discrete devices. It is also shown that measurements which attempt to use the collector-base voltage of the output transistor of the Darlington as a temperature-sensitive-parameter, either alone or in conjunction with an output commutating diode (when present), are too sensitive to the magnitude of the measuring current to be reliable. Also, the use of the base-current screen for hot spots, as used for discrete transistors, is marginally applicable to integrated Darlingtons, but it is shown that the emitter-base voltage sensed during emitter-only switching is quite effective for detecting hot-spot formation.
Optimal Machining Parameter Selection in Titanium Milling Using a Decision Analytic Framework

The paper presents a decision analytic framework for optimal machining parameter selection in titanium milling, considering uncertainty in tool life and stability. An influence diagram showing the decision situation, the corresponding uncertainties and the value was developed. The objective was to select optimum machining parameters to minimize machining cost while considering uncertainty in tool life and stability. The uncertainties were characterized using a probability distribution taking into account all available information. The cost associated with tool failure and unstable cutting conditions was incorporated in the cost formulation. A process probability tree showing the uncertainties and the corresponding costs was constructed. The optimal machining parameters were selected which minimize the expected machining cost. Results show a 90% reduction in machining cost as compared to manufacturer recommended parameters. A discussion section regarding inference and experimental design is included.Copyright © 2014 by ASME
Kinematics with computer graphics

Abstract The impact which computer graphics can have on engineering education is illustrated in this paper by considering the subject area of kinematics. Details of the mathematical modeling needed to support the generation of motion curves and computer graphics simulation for kinematic analysis are given, and a comparison is made with the current popular methods of analysis. Several results of computer graphic displays are given to illustrate the wide variety of situations where computer graphics can add to the teaching and understanding of kinematics.
Studies of cultured human T lymphocytes. I. Production of the T cell growth-promoting lymphokine interleukin-2☆☆☆

Abstract Described herein is a large-scale procedure that has been successfully employed for producing 62 lots (800–3000 ml) of supernatants containing the T cell growth-promoting factor Interleukin-2 (IL-2). The efficiency of these crude, unconcentrated supernatants was documented in studies in which 70 human long-term (>100 days) IL-2-dependent T cell lines were established from 50 different donors. These included lines initiated from the peripheral blood healthy subjects (N = 54), blood of children with active acute lymphoblastic leukemia (N = 6) and the thymus of children undergoing surgery to correct congenital heart defects (N = 10). The underlying concept used in constructing this method emphasizes the requirement of the monocyte-derived macrophage and its Interleukin-1 (IL-1) product to mediate IL-2 production by activated T cells. The most salient feature of this technique is the utilization of buffy coat leukocytes that had been pooled from several blood donors and sustained in spinner cultures for several days prior to polyclonal activation with phytohemagglutinin and pooled B cells of established human lymphoblastoid lines.
On the interpretation of magnetic field induced level crossings in triplet—triplet annihilation in naphthalene and anthracene-doped phenanthrene

Abstract A density matrix formulation has been used to calculate the line shapes of changes in delayed fluorescence arising from level crossings of triplet pair
Effect of edge conditions on test results for concrete

Abstract A study was conducted to determine what theoretical statements can be made concerning the relative magnitudes of experimentally measured properties of concrete (measured on relatively small samples) and the actual properties. The bulk of the paper is concerned with results obtained from triaxial tests with zero surface shear stresses and either uniform normal stresses or uniform normal displacements.
Dynamic crack-tip stresses under stress wave loading —A comparison of theory and experiment

The characterization of the electromagnetic stress wave generator is described. The method of caustics applied to birefringent materials is examined in detail in order to explain the lack of double caustics in Homalite-100. The accuracy of the method of caustics is demonstrated experimentally by using two loading configurations and comparing the results with the theoretical analysis of Freund [1].
Opioid synapses on vasopressin neurons in the paraventricular and supraoptic nuclei of juvenile monkeys.

Abstract Opioid peptide- as well as vasopressin-containing neurons synapse on gonadotropin releasing hormone neurons in juvenile macaques. In this study we performed double-label immunostaining for opioid and vasopressin neurons in the paraventricular and supraoptic nuclei in order to assess their interrelationships. Neuroendocrine neurons in the hypothalamus were prelabeled by microinjection of electron-dense retrograde tracer into the median eminence, and were easily identified in frontal Vibratome sections. Sections through the paraventricular and supraoptic nuclei were immunostained for vasopressin with the peroxidase-antiperoxidase technique, and for opioids using the indirect immunogold method. By light microscopy, opioid-immunoreactive inputs appeared to innervate an average of 39% of the vasopressin neurons in the paraventricular nucleus and 33% in the supraoptic nucleus, and were more prevalent anteriorly. Clusters of opioid afferents formed cup-like calices around major processes of many vasopressin neurons, especially in the paraventricular nucleus. Electron microscopy revealed that these groups of opioid axon terminals made frequent symmetrical and fewer asymmetrical synapses on both neuroendocrine and non-neuroendocrine vasopressinergic cell bodies and dendrites. Our study did not reveal vasopressin opioid synapses in these hypothalamic nuclei, but this does not preclude the possibility of their existence elsewhere. These results indicate that opioid afferents modulate vasopressin neuronal activity in the monkey paraventricular and supraoptic nuclei. Previous results have suggested that corticotropin releasing hormone acts via vasopressinergic neurons to stimulate opioid neuronal activity and to inhibit gonadotropin releasing hormone release. Taken together, the data suggest that stressful stimuli could initiate a series of neuropeptidergic interactions which ultimately alter pulsatile gonadotropin releasing hormone secretion and thus gonadotropin secretion in primates.
A distal mutation perturbs dynamic amino acid networks in dihydrofolate reductase

Correlated networks of amino acids have been proposed to play a fundamental role in allostery and enzyme catalysis. These networks of amino acids can be traced from surface-exposed residues all the way into the active site, and disruption of these networks can decrease enzyme activity. Substitution of the distal Gly121 residue in Escherichia coli dihydrofolate reductase results in an up to 200-fold decrease in the hydride transfer rate despite the fact that the residue is located 15 A from the active-site center. In this study, nuclear magnetic resonance relaxation experiments are used to demonstrate that dynamics on the picosecond to nanosecond and microsecond to millisecond time scales are changed significantly in the G121V mutant of dihydrofolate reductase. In particular, picosecond to nanosecond time scale dynamics are decreased in the FG loop (containing the mutated residue at position 121) and the neighboring active-site loop (the Met20 loop) in the mutant compared to those of the wild-type enzyme, ...
Effects of N-acetylimidazole on human erythrocyte ATPase Activity. Evidence for a tyrosyl residue at the ATP binding site of the (Na+ + K+)-dependent ATpase

Abstract 1. 1. Acetylation of human erythrocytes by N- acetylimidazole alters the structure of stroma prepared from these cells and the degree of alteration appears to be dependent upon the level of the initial treatment. These changes do not occur when stroma are acetylated. 2. 2. Deacetylation by hydroxylamine or mild alkaline treatment causes a complete recovery of the (Na + + K + )-dependent and the Ca2+-stimulated ATPase activities and indicates that the inhibition is due to the acetylation of a tyrosyl residue. There is only partial recovery of the Mg2+-dependent ATPase after deacetylation. 3. 3. ATP or Mg-ATP completely protect the (Na + + K + -dependent ATPase but not the Ca2+-stimulated system. 4. 4. The results indicate that the (Na + + K + -dependent and the Ca2+-stimulated ATpase activities have separate substrate binding site and most likely are separate enzyme systems. 5. 5. Acetylation of human erythrocytes has no effect on d -glucose transport.
Electrical properties of Ag5Te2Cl and Ag3TeBr

Abstract Electrical conductivity measurements on polycrystalline Ag 5 Te 2 Cl indicate the compound undergoes a covalent-superionic phase transition at a temperature of 328 K. Conductivity changes abruptly at the temperature by a factor of 25 while the activation energy for ionic motion transforms from 0.38 eV in the low temperature modification to 0.26 eV in the high temperature modification. Ag 3 TeBr does not exhibit any phase changes throughout the temperature range 150–400 K and its activation energy is found to be 0.35 eV.
Aspects of the meaning of if … then for older preschoolers: Hypotheticality, entailment, and suppositional processes

Abstract The currently accepted notion that young children understand if … then conjunctively in syllogistic tasks, and, concomitantly, that it does not denote entailment and hypotheticality for them, is challenged on conceptual grounds (because those latter two aspects of meaning cannot be assumed to always cooccur in development) and on methodological and empirical grounds in two experiments. Six-year-old preschoolers have been shown to reason biconditionally when syllogistic tasks are presented in discourse contexts and given meaningful clausal contents. Here we support these findings by showing that 6-year-olds demonstrate robust understanding of both the hypotheticality of if … then and the entailment relation denoted by if … then. First, in a task requiring judgments of semantic sensibleness-silliness for contradictions that were resolvable by a hypothetical construal of an if … then frame, the majority of these children viewed if … then as hypothetical. Second, when prompted to explain the consequent clauses of if … then statements from a story, they frequently cited the antecedent clause as an explanation, and were able to support this response by describing a causal chain linking events in the statement; these data suggest that if … then also denotes an entailment relation for young children.
Finite-element deformable sheet-curve models for registration of breast MR images

It is clinically important to develop novel approaches to accurately assess early response to chemoprevention. We propose to quantitatively measure changes of breast density and breast vascularity in glandular tissue to assess early response to chemoprevention. In order to accurately extract glandular tissue using pre- and post-contrast magnetic resonance (MR) images, non-rigid registration is the key to align MR images by recovering the local deformations. In this paper, a new registration method has been developed using finite-element deformable sheet-curve models to accurately register MR breast images for extraction of glandular tissue. Finite-element deformable sheet-curve models are coupling dynamic systems to physically model the boundary deformation and image deformation. Specifically, deformable curves are used to obtain a reliable matching of the boundaries using physically constrained deformations. A deformable sheet with the energy functional of thin-plate-splines is used to model complex local deformations between the MR breast images. Finite-element deformable sheet-curve models have been applied to register both digital phantoms and MR breast image. The experimental results have been compared to point-based methods such as the thin-plate-spline (TPS) approach, which demonstrates that our method is of a great improvement over point-based registration methods in both boundary alignment and local deformation recovery.