cssi/SciSciGPT-SciSciNet huggingface dataset:
Scope and Mechanism of Intramolecular Aziridination of Cyclopent-3-enyl-methylamines to 1-Azatricyclo[2.2.1.02,6]heptanes with Lead Tetraacetate

A series of seven cyclopent-3-en-1-ylmethylamines bearing one, two, or three methyl substituents at the C2, C3, C4, or C(alpha) positions, including the unsubstituted parent, was accessed by ring-closing metatheses of alpha,alpha-diallylacetonitrile (or methallyl variants) and alpha,alpha-diallylacetone followed by hydride reductions or reductive amination, or by Curtius degradations of alpha,alpha-dimethyl- and 2,2,3-trimethylcyclopent-3-enylacetic acids. Oxidation of the primary amines with Pb(OAc)(4) in CH(2)Cl(2), CHCl(3) or benzene in the presence of K(2)CO(3) effected efficient intramolecular aziridinations, in all cases except the alpha-methyl analogue (16), to form the corresponding 1-azatricyclo[2.2.1.0(2,6)]heptanes, including the novel monoterpene analogues, 1-azatricyclene and the 2-azatricyclene enantiomers. The cumulative rate increases of aziridination reactions observed by (1)H NMR spectroscopy in CDCl(3) resulting from the presence of one or two methyl groups on the cyclopentene double bond, in comparison to the rate of the unsubstituted parent amine (1:17.5:>280), indicate a highly electrophilic intermediate as the nitrene donor and a symmetrical aziridine-like transition state. A mechanism is outlined in which the amine displaces an acetate ligand from Pb(OAc)(4) to form a lead(IV) amide intermediate RNHPb(OAc)(3) proposed as the actual aziridinating species.
Theory of quantum nucleation of bubbles in liquid helium

We calculate the rate at which bubbles form by quantum tunneling in liquid helium-3 and helium-4 at negative pressure. We find that quantum tunneling should be observable at temperatures below about 0.1 K in helium-3 and 0.2 K in helium-4, and at pressures close to the critical negative pressure at which the liquid becomes unstable against long wavelength density fluctuations.
Human vision and computer graphics

Is one picture really worth a thousand words? Why do cleverly designed graphic displays make visual information stand out more clearly with strikingly greater impact than numbers buried in pages of computer printout?Graphic output devices shift the burden of integrating information generated by computers onto the human vision system: the sensory channel with the highest capacity for distributed parallel processing. The system consists of hundreds of successive two-dimensional arrays of millions of interconnected parallel computers. Perception seems instantaneous because we are not conscious of the massive amounts of computation that occur. What we consciously “see at a glance” is already a highly structured, synthesized, and summarized version of the actual light intensity mosaic that enters the retina.We will demonstrate some results of the visual structuring that occurs in the human visual system, show why some features stand out instantaneously and others do not, and explain why knowledge of the human input device is crucial to the design of effective computer output devices and displays.
Immunologic influences on emotion regulation

Abstract Recent data document meaningful interactions between the immune system and the brain that provide the foundation for considering the potential influence of immunologic processes on emotion regulation. Studies from both laboratory animals and humans demonstrate that cytokine signals can access the brain and in turn lead to profound changes in neurochemistry, neuroendocrinology and behavior. Interestingly, data suggest that the behavioral and physiological consequences of stressful life experiences may also derive in part from the effects of stress on the immune response. The extant literature on brain–immune interactions is reviewed herein with special emphasis on data derived from patients undergoing treatment with the cytokine, interferon alpha. Consideration is also given to the mechanisms by which cytokines induce behavioral change, including an examination of the differential mechanisms that may be involved in cytokine effects on mood and cognition versus cytokine effects on neurovegetative function. Finally, implications of these findings are examined both from an evolutionary perspective and in terms of their relevance for treatment of patients with neuropsychiatric disorders.
Serum and urinary interleukin-6 in systemic lupus erythematosus

Dysregulation of IL-6 production has been proposed as a pathogenic mechanism in SLE. We asked if serum or urine IL-6 levels could serve as indicators of systemic lupus erythematosus (SLE) disease activity. Using a sensitive enzyme-linked immunosorbent assay (ELISA), we measured serum and urine IL-6 in 56 SLE patients. Disease activity was assessed using a standard clinical index, the Systemic Lupus Activity Measure (SLAM). Only seven of 56 SLE patients had elevated serum IL-6 levels, compared with 1 of 32 controls (NS). SLE disease activity did not correlate with serum IL-6 levels. Sixteen of 50 SLE patients in whom urine IL-6 was measured exhibited elevated urine IL-6 levels, compared with 1 of 17 controls (p = < 0.05). Urine IL-6 levels correlated with overall disease activity and with the presence of active urinary sediment. Our results indicate that serum IL-6 is not a predictor of disease activity in SLE, but that urine IL-6 may be a marker of active nephritis.
Predictive Validity of Explicit and Implicit Threat Overestimation in Contamination Fear.

Abstract We examined the predictive validity of explicit and implicit measures of threat overestimation in relation to contamination-fear outcomes using structural equation modeling. Undergraduate students high in contamination fear (N=56) completed explicit measures of contamination threat likelihood and severity, as well as looming vulnerability cognitions, in addition to an implicit measure of danger associations with potential contaminants. Participants also completed measures of contamination-fear symptoms, as well as subjective distress and avoidance during a behavioral avoidance task, and state looming vulnerability cognitions during an exposure task. The latent explicit (but not implicit) threat overestimation variable was a significant and unique predictor of contamination fear symptoms and self-reported affective and cognitive facets of contamination fear. On the contrary, the implicit (but not explicit) latent measure predicted behavioral avoidance (at the level of a trend). Results are discussed in terms of differential predictive validity of implicit versus explicit markers of threat processing and multiple fear response systems.
The inhibition of chromatin solubilization by proteolytic inhibitors

Abstract Several inhibitors of the proteolysis of histone H1, were examined for their effect on chromatin solubilization in a rabbit thymus nuclear incubation. Tosyl-lysine chloromethyl ketone and Tosylamino-phenylethyl sulfonyl fluoride were inhibitory while leupeptin was without effect.
Microcrack toughening in two-phase multilayered media

This work presents a numerical model of the toughening behavior exhibited when a Mode I macrocrack propagates through alternating tough and brittle layers of a composite. The toughening occurs due to microcracking in brittle layers. Microcracks form at periodic flaw sites in brittle layers when the stress at a site is sufficient to propagate a crack within the layer. An established microcrack is modeled by a dislocation dipole, with Burgers vector chosen to render the normal component of stress equal to zero at the dipole midpoint. R-curves for layered media are predicted as a function of bi-layer thickness, volume fraction, density of flaw sites, and inhomogeneity in fracture toughness and elastic modulus. A critical combination of properties for the onset of R-curve behavior is identified, and features which optimize the upper plateau of the R-curve are discussed in light of experimental observations.
Knot theory and the Casson invariant in Artin presentation theory

In Artin presentation theory, a smooth, compact four-manifold is determined by a certain type of presentation of the fundamental group of its boundary. Topological invariants of both three-and four-manifolds can be calculated solely in terms of functions of the discrete Artin presentation. Gonzalez-Acuna proposed such a formula for the Rokhlin invariant of an integral homology three-sphere. This paper provides a formula for the Casson invariant of rational homology spheres. Thus, all 3D Seiberg-Witten invariants can be calculated by using methods of the theory of groups in Artin presentation theory. The Casson invariant is closely related to canonical knots determined by an Artin presentation. It is also shown that any knot in any three-manifold appears as a canonical knot in Artin presentation theory. An open problem is to determine 4D Seiberg-Witten and Donaldson invariants in Artin presentation theory.
Simplifying robot hands using recursively scaled power grasps

This paper presents a concept for extending the functionality of robot hands so that they can better manipulate objects too small for an enveloping power grasp. Rather than pinching these objects between the fingertips of a hand, a miniature hand is embedded recursively on the end of a finger, enabling a power grasp on a smaller scale. The mechanics of designing such a gripper to operate without adding additional tendons are analyzed within the framework of underactuated elastic mechanisms. A simplified robot hand is demonstrated having a recursive gripper, and the process of picking up a pen and writing using a multi-scale grasp is demonstrated.
The role of interpersonal liking in building trust in long-term channel relationships

This article explores the important role of liking in the development of the buyer’s trust in the sales rep. The authors argue that liking’s role is richer and qualitatively different from that of the more cognitive antecedents of trust. They posit that many cognitive antecedents of trust operate mainly through liking. They argue that as the buyer-sales rep relationship matures, liking plays an even more important role in influencing trust. The authors empirically test a model delineating the mediating role of liking in developing trust. They find that when the relationship between the buyer and the sales rep is young, liking partially mediates the effect of similarity of business values and fully mediates the influence of frequency of personal interaction on trust. Moreover, as the buyer’s relationship with the rep ages, liking takes the foreground in trust development, while more cognitive antecedents recede into the background.
Cell surface receptors for signal transduction and ligand transport: a design principles study.

Receptors constitute the interface of cells to their external environment. These molecules bind specific ligands involved in multiple processes, such as signal transduction and nutrient transport. Although a variety of cell surface receptors undergo endocytosis, the systems-level design principles that govern the evolution of receptor trafficking dynamics are far from fully understood. We have constructed a generalized mathematical model of receptor–ligand binding and internalization to understand how receptor internalization dynamics encodes receptor function and regulation. A given signaling or transport receptor system represents a particular implementation of this module with a specific set of kinetic parameters. Parametric analysis of the response of receptor systems to ligand inputs reveals that receptor systems can be characterized as being: i) avidity-controlled where the response control depends primarily on the extracellular ligand capture efficiency, ii) consumption-controlled where the ability to internalize surface-bound ligand is the primary control parameter, and iii) dual-sensitivity where both the avidity and consumption parameters are important. We show that the transferrin and low-density lipoprotein receptors are avidity-controlled, the vitellogenin receptor is consumption-controlled, and the epidermal growth factor receptor is a dual-sensitivity receptor. Significantly, we show that ligand-induced endocytosis is a mechanism to enhance the accuracy of signaling receptors rather than merely serving to attenuate signaling. Our analysis reveals that the location of a receptor system in the avidity-consumption parameter space can be used to understand both its function and its regulation.
Induction of tyrosine 3-monooxygenase in adrenal medulla: role of protein kinase activation and translocation

The transsynaptic induction of tyrosine 3-monooxygenase (TH) in rat adrenal medulla is preceded by an early increase in the ratio of cyclic adenosine monophosphate (AMP) to cyclic guanosine monophosphate, an activation of cytosol cyclic AMP-dependent protein kinase, and a subsequent translocation of protein kinase catalytic subunits from cytosol to subcellular particles. As a result of this translocation, nuclear protein kinase activity increases during the induction of TH. Transection of splanchnic nerve reverts these events and prevents the induction of TH. Thus, adrenal medulla activation and translocation of cyclic AMP-dependent protein kinase may act as a long-range messenger for the genetic regulation of TH synthesis.
The superconductive critical temperature and the electronic specific heat of impur1e tin

Abstract From measurements of the threshold magnetic field as a function of temperature for specimens of tin containing 0.04 to 2.0 at. per cent of various impurities we have obtained the superconductive critical temperature, T c , of these samples, as well as the temperature coefficient, γ, of the electronic specific heat of the normal phase. We find that the change in T c produced by the impurities consists of two parts. There is a decrease which is linearly proportional to the increase in residual resistance ratio and hence to the decrease in electronic mean free path. Superimposed on this decrease there is an increase in T c . Our results also show that the measurable changes in γ are positive for all solutes, indicating a minimum in the density of states at or near the Fermi energy. We believe that the second, positive part of the change in T c is due to the increase in γ, and find that the correlation between these quantities is in reasonable agreement with the recent theory of B ar-Deen , C ooper and S chrieffer . 19 During the course of our work we also obtained a value of γ for pure tin which agrees well with a recent calorimetric result. Measurements of the residual resistance ratio of our samples show, as expected, that below the solubility limit this ratio increases linearly with impurity concentration with a slope which depends on the atomic radius of the impurity as well as on its valence.
Perceptual classification boundaries between 2D shapes

One of the key variables that have been used for identifying objects in two-dimensional imagery is shape. Humans have the ability to discriminate between shapes and can perceive an imperfect shape as belonging to a particular object class. Each object class has a boundary where a human perceives an object as belonging to one class or the other. Perceptual classification boundaries define the human perception that classifies a shape as belonging to a particular object class. In this paper, the perceptual difference between several primitive two-dimensional object shapes is examined. Unlike the human, computer recognition algorithms are typically designed to recognize a finite number of classes of objects. This paper focuses on two-class and three-class recognition problems using simple primitive shapes consisting of a single-filled, closed loop contour. To determine the perceptual classification boundary, one primitive shape is morphed into another, and a group of persons are used to quantify where the perceived boundary is located between objects. Various shape measures are then applied to the primitive shapes to determine how well some current measures can quantify the perceived classification boundary. The addition of gaussian noise to the primitive two-dimensional shapes is also examined along with quantitative and perceived human results. The results suggest that the tested quantitative measures do not provide results similar to human perception. Some measures are better than others at achieving perceptual classification. The paper demonstrates that an approximate perceptual classification measure can be achieved by using human observer perceptual thresholds along with a quantitative measure.
A RESPONSE TO BRUNI AND SUGDEN

An article by Luigino Bruni and Robert Sugden published in this journal argues that market relations contain elements of what they call ‘fraternity’. This Response demonstrates that my own views on interpersonal relations and markets – which originated in the feminist analysis of caring labour – are far closer to Bruni and Sugden’s than they acknowledge in their article, and goes on to discuss additional important dimensions of sociality that they neglect.
A Plowing Theory of Yarn Surface Friction

Current theories of friction do not explain the fact that the friction of many fibers on typical guide surfaces is a function of the guide surface roughness. This friction has been found to vary inversety with increasing roughness within certain levels. In this paper a theory to explain the phenomenon is proposed. It is based upon work by Bowden and Tahor and others, in which the plowing of metal in front of a slider of a harder material than the surface upon which it slides is considered in addition to the shearing of junctions made between the two metals. An analysis by Bowden and Tabor, in which one hemispherical asperity is studied, is extended. A mathematical model of the friction effect is set up involving many asperities, all of equal radius. Plowing friction is then found to be an inverse function of the radius of the asperities and of the square root of the number of asperities. To test the relationship derived from this theory some introductory experimental work was done. The friction of yarn on...
THE EVOLUTION OF CORONAL MASS EJECTION DENSITY STRUCTURES

We present a discussion of the time evolution of the mass and energy of a model coronal mass ejection (CME), analyzing both synthetic coronograph images and three-dimensional data of the numerical ideal magnetohydrodynamics (MHD) simulation. Our global steady state coronal model possesses high-latitude coronal holes and a helmet streamer structure with a current sheet near the equator, reminiscent of near solar minimum conditions. Within this model system, we drive a CME to erupt by the introduction of a Gibson-Low magnetic flux rope that is embedded in the helmet streamer in an initial state of force imbalance. The flux rope rapidly expands and is ejected from the corona with maximum speeds in excess of 1000 km s-1 driving a fast-mode shock that propagates from the inner corona to a distance of 1 AU. We study the mass and energetics of the CME inferred from the three-dimensional results of the simulation, as well as calculated from synthetic coronograph images produced at different times. The two-dimensional plane-of-sky density structure of a CME is discussed for wide-angle coronographs, such as the Heliospheric Imager (HI-2) on board STEREO (Solar Terrestrial Relations Observatory), and compared with the three-dimensional density structure. We found that the CME mass derived from the synthetic coronographic images is an underestimate by about 50% of the total mass of the CME according to the three-dimensional data. Two main reasons can be invoked: the poor assumption that all the mass of the CME is in the plane of the sky and the wrapping of the front shock around the density-depleted cavity, which leads to an apparent decrease in brightness of the front shock.
The Effect of Going-Concern Diagnosticity on Market Prices

Large unexpected corporate failures associated with the global financial crisis heightened investors’ and regulators’ concerns about the diagnosticity of auditors’ going-concern opinions. Consistent with these concerns, extant research indicates that going-concern opinions are only moderately diagnostic at best, with only fifty to sixty percent of financially distressed firms receiving going-concern audit opinions prior to bankruptcy. Using an experimental market, we show that under conditions of moderate diagnosticity, investors discount the going-concern signal. Compared to a market with high diagnosticity, investors penalize the stock prices of non-bankrupt firms and fail to adequately discount the prices of bankrupt firms, even in instances when the going-concern signal accurately predicted the bankruptcy outcome. Interestingly, we find that a market with moderately diagnostic going-concern opinions provides no greater informational value than a market without going-concern opinions altogether. Specifically, we demonstrate that stock price behavior and, in turn, average investor earnings are no different in a market with moderate diagnosticity as compared to a market that lacks any going-concern signal. These findings have implications for regulators who are interested in improving the quality of going-concern opinions.
The extracellular versus intracellular mechanisms of inhibition of TCR-triggered activation in thymocytes by adenosine under conditions of inhibited adenosine deaminase.

The absence or low levels of adenosine deaminase (ADA) in humans result in severe combined immunodeficiency (SCID), which is characterized by hypoplastic thymus, T lymphocyte depletion and autoimmunity. Deficiency of ADA causes increased levels of both intracellular and extracellular adenosine, although only the intracellular lymphotoxicity of accumulated adenosine is considered in the pathogenesis of ADA SCID. It is shown that extracellular but not intracellular adenosine selectively inhibits TCR-triggered up-regulation of activation markers and apoptotic events in thymocytes under conditions of ADA deficiency. The effects of intracellular adenosine are dissociated from effects of extracellular adenosine in experiments using an adenosine transporter blocker. We found that prevention of toxicity of intracellular adenosine led to survival of TCRcross-linked thymocytes in long-term (4 days) assays, but it was not sufficient for normal T cell differentiation under conditions of inhibited ADA. Surviving TCR-cross-linked thymocytes had a non-activated phenotype due to extracellular adenosine-mediated, TCR-antagonizing signaling. Taken together the data suggest that both intracellular toxicity and signaling by extracellular adenosine may contribute to pathogenesis of ADA SCID. Accordingly, extracellular adenosine may act on thymocytes, which survived intracellular toxicity of adenosine during ADA deficiency by counteracting TCR signaling. This, in turn, could lead to failure of positive and negative selection of thymocytes, and to additional elimination of thymocytes or autoimmunity of surviving T cells.
Beyond the Number Domain

In a world without numbers, we would be unable to build a skyscraper, hold a national election, plan a wedding or pay for a chicken at the market. The numerical symbols used in all these behaviors build on the approximate number system (ANS) which represents the number of discrete objects or events as a continuous mental magnitude. Here, we first discuss evidence that the ANS bears a set of behavioral and brain signatures that are universally displayed across animal species, human cultures and development. We then turn to the question of whether the ANS constitutes a specialized cognitive and neural domain – a question central to understanding how this system works, the nature of its evolutionary and developmental trajectory and its physical instantiation in the brain.
Development of a framework and coding system for modifications and adaptations of evidence-based interventions

Background: Evidence-based interventions are frequently modified or adapted during the implementation process. Changes may be made to protocols to meet the needs of the target population or address differences between the context in which the intervention was originally designed and the one into which it is implemented [Addict Behav 2011, 36(6):630–635]. However, whether modification compromises or enhances the desired benefits of the intervention is not well understood. A challenge to understanding the impact of specific types of modifications is a lack of attention to characterizing the different types of changes that may occur. A system for classifying the types of modifications that are made when interventions and programs are implemented can facilitate efforts to understand the nature of modifications that are made in particular contexts as well as the impact of these modifications on outcomes of interest. Methods: We developed a system for classifying modifications made to interventions and programs across a variety of fields and settings. We then coded 258 modifications identified in 32 published articles that described interventions implemented in routine care or community settings. Results: We identified modifications made to the content of interventions, as well as to the context in which interventions are delivered. We identified 12 different types of content modifications, and our coding scheme also included ratings for the level at which these modifications were made (ranging from the individual patient level up to a hospital network or community). We identified five types of contextual modifications (changes to the format, setting, or patient population that do not in and of themselves alter the actual content of the intervention). We also developed codes to indicate who made the modifications and identified a smaller subset of modifications made to the ways that training or evaluations occur when evidence-based interventions are implemented. Rater agreement analyses indicated that the coding scheme can be used to reliably classify modifications described in research articles without overly burdensome training. Conclusions: This coding system can complement research on fidelity and may advance research with the goal of understanding the impact of modifications made when evidence-based interventions are implemented. Such findings can further inform efforts to implement such interventions while preserving desired levels of program or intervention effectiveness.
A general approach to linear and non-linear dispersive waves using a Lagrangian

The basic property of equations describing dispersive waves is the existence of solutions representing uniform wave trains. In this paper a general theory is given for non-uniform wave trains whose amplitude, wave-number, etc., vary slowly in space and time, the length and time scales of the variation in amplitude, wave-number, etc., being large compared to the wavelength and period. Dispersive equations may be derived from a variational principle with appropriate Lagrangian, and the whole theory is developed in terms of the Lagrangian. Boussinesq's equations for long water waves are used as a typical example in presenting the theory.
Monte Carlo simulation of photon propagation in diffusive media

Interest in the study of photon migration through biological tissue was prompted by the rapid development of optical devices used in the field of diagnostic and therapeutic medicine. These optical devices depend upon the behavior of biological tissue in response to irradiation by ultraviolet, infrared and visible light sources. The optical properties of tissue can be studied extensively using computer simulation methods. A Monte Carlo model has been developed to study photon diffusion in a homogeneous diffusive isotropically scattering tissue medium. The depth distribution of the photons within the simulated medium confirms the use of surface optical measurements to access deep tissue optical properties.
The Natural History of Idiopathic Chest Pain in Children: A Follow-up Study

Repetitive chest pain of obscure origin is commonly encountered in older children and adolescents. A questionnaire study was conducted to determine the long-term outcome in 31 patients diagnosed as having idiopathic recurrent chest pain after an average 4.1-year follow-up period. Although 45 percent reported having had persistent symptoms, chest pain had disappeared in 81 percent of those followed more than 3 years. Equally reassuring is the fact that in no case did occult disease subsequently appear to account for the initial symptoms. This study supports the current clinical approach of limited diagnostic evaluation and reassurance in the management of these patients.
Improving the accuracy of the on-site calibrations of multi-function electrical standards

This paper describes some improvements to the accuracy of the on-site measuring system of the National Research Council of Canada (NRC) Travelling Standard Program. This NRC service provides traceable calibrations of the multifunction electrical standards that electrical utilities and other organizations use to test and verify electricity revenue meters. The calibration program can be used to show that the measurements of the electricity revenue meters are traceable to the national standard, a requirement of the trade metrology legislation in Canada.
Murine albino-deletion complex: high-resolution microsatellite map and genetically anchored YAC framework map.

The murine albino-deletion complex developed as part of the Oak Ridge specific-locus test covers 6-11 cM of chromosome 7. This complex has proven to be a valuable resource for localizing traits to a small target region suitable for positional cloning. In this study, we mapped the endpoints of deletions in this complex using all of the available Mit simple-sequence length polymorphism (SSLP) markers. Concurrently, this mapping has determined the map order of nearly all of the SSLP markers, most of which were previously unresolved. The SSLP-based deletion map was confirmed and genetic distances were determined using the European Collaborative Interspecific Backcross panel of nearly a thousand mice. The average SSLP marker resolution is 0.3-0.4 cM, comparable to the cloning capacity of yeast artificial chromosomes (YACs). The SSLP markers were then used to construct a genetically anchored YAC framework map that further confirms the deletion map. We find that the largest deleted region distal to Tyr is about two to three times larger than the largest proximal deleted region, and the original C3H/101 regions flanking the deletions (moved to an St2A c(ch)/c(ch) background) are smaller than anticipated, which we suggest may result from increased recombination rates immediately flanking the deleted regions.
Diffusive boundary layers over varying topography

Diffusive bottom boundary layers can produce upslope flows in a stratified fluid. Accumulating observations suggest that these boundary layers may drive upwelling and mixing in mid-ocean ridge flank canyons. However, most studies of diffusive bottom boundary layers to date have concentrated on constant bottom slopes. We present a study of how diffusive boundary layers interact with various idealized topography, such as changes in bottom slope, slopes with corrugations and isolated sills. We use linear theory and numerical simulations in the regional ocean modeling system (ROMS) model to show changes in bottom slope can cause convergences and divergences within the boundary layer, in turn causing fluid exchanges that reach far into the overlying fluid and alter stratification far from the bottom. We also identify several different regimes of boundary-layer behaviour for topography with oceanographically relevant size and shape, including reversing flows and overflows, and we develop a simple theory that predicts the regime boundaries, including what topographies will generate overflows. As observations also suggest there may be overflows in deep canyons where the flow passes over isolated bumps and sills, this parameter range may be particularly significant for understanding the role of boundary layers in the deep ocean.
On the Effects of Memory Latency and Bandwidth on Supercomputer Application Performance

Since the first vector supercomputers in the mid-1970's, the largest scale applications have traditionally been floating point oriented numerical codes, which can be broadly characterized as the simulation of physics on a computer. Supercomputer architectures have evolved to meet the needs of those applications. Specifically, the computational work of the application tends to be floating point oriented, and the decomposition of the problem two or three dimensional. Today, an emerging class of critical applications may change those assumptions: they are combinatorial in nature, integer oriented, and irregular. The performance of both classes of applications is dominated by the performance of the memory system. This paper compares the memory performance sensitivity of both traditional and emerging HPC applications, and shows that the new codes are significantly more sensitive to memory latency and bandwidth than their traditional counterparts. Additionally, these codes exhibit lower base-line performance, which only exacerbates the problem. As a result, the construction of future supercomputer architectures to support these applications will most likely be different from those used to support traditional codes. Quantitatively understanding the difference between the two workloads will form the basis for future design choices.
Rootletin, a novel coiled-coil protein, is a structural component of the ciliary rootlet

The ciliary rootlet, first recognized over a century ago, is a prominent structure originating from the basal body at the proximal end of a cilium. Despite being the largest cytoskeleton, its structural composition has remained unknown. Here, we report a novel 220-kD protein, designated rootletin, found in the rootlets of ciliated cells. Recombinant rootletin forms detergent-insoluble filaments radiating from the centrioles and resembling rootlets found in vivo. An mAb widely used as a marker for vertebrate rootlets recognizes an epitope in rootletin. Rootletin has a globular head domain and a tail domain consisting of extended coiled-coil structures. Rootletin forms parallel in register homodimers and elongated higher order polymers mediated by the tail domain alone. The head domain may be required for targeting to the basal body and binding to a kinesin light chain. In retinal photoreceptors where rootlets appear particularly robust, rootlets extend from the basal bodies to the synaptic terminals and anchor ER membranes along their length. Our data indicate that rootlets are composed of homopolymeric rootletin protofilaments bundled into variably shaped thick filaments. Thus, rootletin is the long-sought structural component of the ciliary rootlet.
Multiple immune functions in rats fed echinacea extracts

This study evaluated acquired-immune functions representing the three major branches of the immune system in male rats fed a commercially available echinacea product. An additional comparison of effects on antibody formation in male and female rats was done using the commercial echinacea product and two echinacea tinctures marketed by local herbalists. In initial testing, we found no evidence of altered natural killer cell activity, T cell-mediated delayed-type hypersensitivity, or specific antibody formation in male rats given either a 225 mg/kg or 50 mg/kg of the commercial echinacea for 6 weeks. Antibody formation was significantly suppressed in female but not male rats given 250 mg/kg for 2 weeks of the commercial echinacea. The local products tested had no effect on antibody formation. We concluded that our study provided no supporting evidence for immunostimulatory activity by the echinacea preparations we examined and, in fact, may be immunosuppressive under some conditions.
On Node Isolation Under Churn in Unstructured P2P Networks with Heavy-Tailed Lifetimes

Previous analytical studies [12], [18] of unstructured P2P resilience have assumed exponential user lifetimes and only considered age-independent neighbor replacement. In this paper, we overcome these limitations by introducing a general node-isolation model for heavy-tailed user lifetimes and arbitrary neighbor-selection algorithms. Using this model, we analyze two age-biased neighbor-selection strategies and show that they significantly improve the residual lifetimes of chosen users, which dramatically reduces the probability of user isolation and graph partitioning compared to uniform selection of neighbors. In fact, the second strategy based on random walks on age-weighted graphs demonstrates that for lifetimes with infinite variance, the system monotonically increases its resilience as its age and size grow. Specifically, we show that the probability of isolation converges to zero as these two metrics tend to infinity. We finish the paper with simulations in finite-size graphs that demonstrate the effect of this result in practice.
Intravenous Self-Administration: Response Rates, the Effects of Pharmacological Challenges, and Drug Preference

Intravenous self-administration preparations, utilizing a chronic indwelling catheter, have been developed for the rat, rhesus monkey, dog, squirrel monkey, pig, baboon, cat, and mouse. A wide variety of psychoactive drugs has been tested in these animal preparations which are considered to be reliable predictors of the abuse potential of drugs. Maintained self-administration is taken as evidence of reinforcing effect, and therefore abuse potential, and has been reported for most of the drugs that humans abuse. Use of the self-administration technique also predicts that some drugs not widely available for human use would be abused if available. Long-term drug access results in drug-intake patterns and drug-induced effects in animals that are similar to those seen in humans. The self-administration technique has been widely used to determine the neurotransmitter basis of the reinforcing effects of drugs. Drug preference and reinforcement magnitude have been estimated by comparing the self-administration of two or more drugs available under various experimental conditions, including choice procedures, progressive-ratio reinforcement schedules, and chain reinforcement schedules.
Lipoxygenase metabolites in the rat gastric microvascular response to intragastric ethanol

The role of lipoxygenase metabolites in ethanol-induced gastric mucosal injury and submucosal microvascular change in the rat was studied by in vivo microscopy. Intragastric ethanol-instillation caused marked submucosal venular constriction, dilatation of small arterioles, and corpus mucosal gross lesion formation. The venoconstriction was greater in the lesion than in the nonlesion area. Intragastric pretreatment with either BW755C, a lipoxygenase inhibitor, or Rioprostil, a synthetic prostaglandin E1 analogue, significantly inhibited both the ethanol-induced venoconstriction and the gross lesion formation. In contrast, pretreatment by the submucosal application of either BW755C (50 micrograms/ml) or Rioprostil (50-500 ng/ml) had no effect on either the submucosal venoconstriction or the mucosal lesion formation. In conclusion, leukotrienes released from the gastric mucosa appear to be involved in the ethanol-induced submucosal venoconstriction associated with gastric mucosal injury. Prostaglandin pretreatment protects against this venoconstriction and gross lesion by a mucosal effect but not by a direct effect on submucosal venules.
Focusing the Multifactor Test for Employee Status: The Restatement’s Entrepreneurial Formulation

The American Law Institute’s twenty-first century mission to restate for the first time American employment law carried the responsibility to provide more clear guidance on the law’s critical distinction between employees and independent contractors. This distinction delineates the scope not only of federal employee protection and benefit statutes, but also of employee protections and benefits conferred by state statutory and common law. A Restatement of Employment Law, however, like any Restatement, could not formulate clearer or otherwise more desirable doctrine from the whole cloth of the views and values of the Reporters or the ALI membership. The Restatement could not offer a new rule of decision. It could only offer a better explanation of what has been the underlying basis of a majority of the better decisions limning the employee-employer distinction. Doing so required close examination of the various unstructured multifactor tests that had been used over the past several decades. The Restatement had to determine how and why the better decisions applied the right-to-control factor and the other factors listed among the various multifactor tests. The Restatement needed to provide guiding principles to render the multifactor tests more focused and predictable. We did so by describing as independent businesspersons those with retained discretion to enhance their independent returns. Truly independent businesspersons retain discretion to enhance their returns or profits by making important business decisions in their own interest. These important decisions, the cases revealed, include the allocation of the labor of others, the allocation of capital, and the allocation of the service providers’ own labor. Or, as we expressed it in the black letter of § 1.01(2), “whether to hire and where to assign assistants, whether to purchase and where to deploy equipment, and whether and when to provide service to other customers.”
Democratic Citizenship and the Practice of Rights

We make rights claims for all kinds of reasons, under vastly different circumstances and in a host of distinctive contexts. And we do this all around the globe. But why do we make rights claims? What do we intend to do when we engage in this activity? And what is it that we actually do, regardless of our intentions, when we make rights claims? In this paper, I argue that making rights claims is an activity that is vital to the cultivation of democratic citizenship. More specifically, I suggest that it is through rights claiming that we come to learn and hone the important civic skills of persuasion and judgment and have the opportunity to challenge stigma and shape new conceptions of the self. I make this case by examining what two South African civil society organizations - the Treatment Action Campaign and Mothers2Mothers - have done to bring to fruition their country's Constitutional promise to protect and promote women's rights and access to health care. This analysis of rights as a practice of democratic politics poses a challenge to more traditional philosophical understandings of rights as trumps, whether these are affirmative or critical. And it does so by drawing on the insights of the philosophy of language and investigating rights through the lens of speech act theory. In addition, it engages with debates, particularly among feminists, about the means to and value of fighting for women's reproductive, sexual, and health rights.
Sports Gone Beyond Wild

Letter to the Editor gives readers a chance to comment on articles we publish and on other Issues Important to sports medicine practitioners. Illustrative figures are welcome. Send letters to Editor, THE PHYSICIAN AND SPORTSMEDICINE, 4530 W 77th St, Minneapolis, MN 55435; e-mail to psmletters@mcgraw-hlll.com.
Self-administration of the D1 agonist SKF 82958 is mediated by D1, not D2, receptors.

We have previously reported that two D1 dopamine agonists, SKF 82958 and SKF 77434, are readily self-administered by rats. However, due to the limited selectivities of these agents, it was not possible to attribute their reinforcing effects exclusively to their D1 actions. To assess the relative involvement of D1 and D2 receptors in SKF 82958 reinforcement, rats were pretreated 30 min before self-administration sessions with either the D1-selective antagonist (+)SCH 23390 or the D2-selective antagonist raclopride. The D1 antagonist (+)SCH 23390 (5–20 µg/kg, SC) produced significant, dose-related (compensatory) increases in SKF 82958; in contrast, the D2 antagonist raclopride (25–400 µg/kg, SC) did not significantly increase SKF 82958 self-administration, although raclopride did increase cocaine self-administration. Compensatory increases in self-administration rates are thought to reflect antagonist-induced reductions in drug reinforcement. Hence, we conclude that SKF 82958 self-administration depends on activation of a D1-regulated reinforcement substrate.
The Effect of Various Lead Species on the Leaching Behavior of Borosilicate Waste Glass

A borosilicate nuclear waste glass was static leached in pure water, silicate water, and brine solution. Three different forms of lead were included in specified corrosion cells to assess the extent to which various lead species alter the leaching behavior of the glass. Weight loss data indicated that Pbm and Pb0 greatly reduce the weight loss of glass when leached in pure water, and similar effects were noted in silicate and brine. Si concentrations, which were substantial in the glass-alone leachate, were reduced to below detection limits in all pure water cells containing a lead form. Lead concentration levels in the leachate were controlled by lead form solubility and appeared to be a significant factor in influencing apparent leaching behavior. Surface analysis revealed surface crystals, which probably formed when soluble lead in the leachate reacted with dissolved or activated silica at the glass surface. The net effect was to reduce the release of some glass constituents to the leachate, although it was not clear whether the actual corrosion of the glass surface was reduced. Significantly different corrosion inhibiting effects were noted among lead metal and two forms of lead oxide.
Detection of Salmonellae in Frozen Poultry Products Using the Banwart Flask

Abstract INTRODUCTION WITH the increased emphasis on quality control in food products, the need for a procedure to simplify and accelerate the determination of the presence or absence of salmonellae has been intensified. Banwart (1968) described a system using a glass flask which provides this capability and it has been shown to be useful in the detection of salmonellae in fresh chicken and processed turkey rolls (Banwart, 1969). These experiments were conducted to determine the usefulness of the glass apparatus to determine the presence or absence of salmonellae in frozen poultry pies and in frozen dinner products. EXPERIMENTAL Preparation of the Banwart flask. The flask described by Banwart (1968) consists of a central chamber from which three U tubes project through the container. Semisolid SIM and mannitol purple (MP) agars were prepared as described by Banwart (1968) and used in two of the side tubes. Into the third side arm was…
Stochastic Expectations: Good Mathematics, Bad Economics

An example is used to show that efficient market expectations are not the same as expectations in a stochastic process. An implication is that efficient market expectations need not have stochastic properties like orthogonality and variance bounds. Failure to recognize this fact has led to bad economic analysis.