cssi/SciSciGPT-SciSciNet huggingface dataset:
Resource contributions from dreissenid mussels to the benthic algae Lyngbya wollei (Cyanobacteria) and Cladophora glomerata (Chlorophyta)

Dreissena spp. (zebra and quagga mussels) are invasive to North America and increase light to the benthos, provide hard structure for algal attachment, and may contribute limiting nutrients to benthic algae, thereby facilitating algal blooms. We conducted experiments to determine how Dreissena affect nutrient stoichiometry and growth of Lyngbya wollei and Cladophora glomerata, two benthic algal species recently increasing in biomass in parts of the Laurentian Great Lakes, combined with a field survey to determine the likelihood of L. wollei co-occurrence with Dreissena. L. wollei had a significantly higher concentration of carbon, nitrogen, phosphorus, potassium, and sulfur when grown with live Dreissena. C. glomerata had greater biomass in tanks with live Dreissena, but did not have significant increases in nutrient concentration like L. wollei did. Neither algal species increased in growth due to the added structure of Dreissena shells. L. wollei biomass was greater in the presence of Dreissena during 1 year (of two) of our field survey. This field survey also showed that L. wollei and Dreissena are likely to co-occur. These results suggest that Dreissena provide several nutrients to benthic algae, and these added resources can promote algal growth and consequently blooms.
Pulsation Modes of Spherical Stellar Systems

Kuhn & Miller (1989, KM hereafter) proposed that a small stellar system in orbit around a large galaxy could be heated through resonant coupling between the orbital motion and internal modes of oscillation of the satellite. They further argued that the apparently large mass-to-light (M/L) ratios of dwarf spheroidal (dSph) galaxies around the Milky Way (e.g., Armandroff, Olszewski & Pryor 1995) could be illusory because the satellites are far from virial equilibrium as a consequence of such resonant heating. We note that if the true M/Ls are small, some dSphs have much more kinetic energy than is required to unbind them; a resonant pumping mechanism which adds a modest amount of energy each cycle could not achieve this (Pryor 1996).
Treatment of cerebral vasospasm. Usefulness of Swan-Ganz catheter monitoring of volume expansion

A practical approach to the treatment of neurological deficits associated with cerebral vasospasm by means of volume expansion and hypertension is illustrated by the management of two patients. In each instance, monitoring of cardiac and volume status was performed with a triple-lumen thermodilution Swan-Ganz catheter to determine what mean pulmonary artery wedge pressure would generate the greatest cardiac output. Intravascular volume was expanded with increased fluids, albumin, and blood. Neurological deficits in both patients were reversed completely. Neither patient developed pulmonary hypoxia, congestive heart failure, pulmonary edema, myocardial infarction, or symptoms of intracranial hypertension.
Mesoscopic Patterns of Neural Activity Support Songbird Cortical Sequences

Time-locked sequences of neural activity can be found throughout the vertebrate forebrain in various species and behavioral contexts. From “time cells” in the hippocampus of rodents to cortical activity controlling movement, temporal sequence generation is integral to many forms of learned behavior. However, the mechanisms underlying sequence generation are not well known. Here, we describe a spatial and temporal organization of the songbird premotor cortical microcircuit that supports sparse sequences of neural activity. Multi-channel electrophysiology and calcium imaging reveal that neural activity in premotor cortex is correlated with a length scale of 100 µm. Within this length scale, basal-ganglia–projecting excitatory neurons, on average, fire at a specific phase of a local 30 Hz network rhythm. These results show that premotor cortical activity is inhomogeneous in time and space, and that a mesoscopic dynamical pattern underlies the generation of the neural sequences controlling song.
WHO WAS z-BEST OLYMPIAN IN 2008 AND 2012?

The authors use z-scores (i.e., the number of standard deviations above the mean) to gauge the dominance of gold medalists in individual swimming, track, and gymnastic events at the 2008 and 2012 Summer Olympic Games. Since a last place finisher’s time or score could dramatically skew the results, the ninety-six z-scores (forty-eight for each Olympics) are recalculated for the women’s and men’s other seven finalists in each of twenty-six individual swimming events, twelve track events, and four (six) gymnastic events for women (men). Surprisingly, using these standardized scores (and recalculated z-scores), the most dominant Olympic champion was neither swimmer Michael Phelps nor sprinter Usain Bolt.
Seasonal variation and cotton-corn rotation in the spatial distribution of Rotylenchulus reniformis in Mississippi cotton soils.

Horizontal and vertical distribution of the reniform nematode, Rotylenchulus reniformisLinford and Oliveira, was examined over a 3-yr period in Mississippi cotton soils. Two naturally infested cotton fields (8.1 ha each) were examined to determine the effects of continuous cotton production and a cotton-corn rotation system on the nematode population dynamics in two different seasons (spring and fall). Sixteen grids (0.4 ha) were established in each field. Both fields were grid-mapped with 16 points on 0.4-ha grids using a Global Positioning System (GPS). A single soil core, 5.08-cm diameter × 121.92 cm deep, was collected from each grid intersection and divided into 8 sample depths. Reniform nematodes were found at each of 16 geo-referenced sample sites and in all of the eight sampling depths. The number of reniform nematodes varied from 10 to 2,500 per 100 cm3 soil across sample sites. The nematode population appeared to have a non-clustered horizontal distribution across both the continuous cotton production and cotton-corn rotation fields. Reniform nematode numbers also differed by season. The sampling time and depth were associated with nematode density. In the continuous cotton production field, nematode numbers found in the upper soil profile were higher in the fall than in the spring. In the cottoncorn rotation field after corn was planted, more nematodes were recovered in the lower soil profiles in the fall. Corn and cotton rotations affected both nematode numbers and distribution in relation to soil depth. The recovery of reniform nematodes deep in the soil profile may help explain why this nematode is capable of reaching high levels in the soil after a single year rotation with corn.
A COMPARISON OF AC AND DC EYE MOVEMENT RECORDING

This study demonstrates the distortions introduced into the electro-oculographic record as a function of choice of recorder time constant. Controlled waking eye movements were simultaneously recorded on five separate channels from the same pair of nonpolarizable Ag/AgCl electrodes. Time constants for these channels were DC, 3 sec, 1 sec, 0.3 sec, and 0.1 sec. Results indicate that eye movement recorded through short time constants cannot differentiate between rapid eye movement and saccadic components of slow eye movements, cannot follow slow smooth eye movements, and cannot show the position of the eyes when they are not in motion. The use of DC coupling makes it possible to record these three classes of events faithfully.
High-resolution Z-contrast imaging and EELS study of functional oxide materials.

Abstract Functional complex-oxide materials show a wide variety of properties and behaviors that cannot be found in any other class of materials, including high-temperature superconductivity and colossal magneto resistance. Consequently, this group of oxide materials has become the focus of many experimental as well as theoretical studies, aiming at understanding the fundamental mechanisms and properties that govern these complex structures. Here, we will review our high-resolution Z-contrast imaging and electron energy-loss studies of two complex-oxide materials systems, more specifically low-angle tilt grain-boundaries in YBa2Cu3O7 (YBCO), and the spin-state transition in LaCoO3. It will be shown that the O K-edge pre-peak can be used to quantify the hole-concentration in the vicinity of the dislocation core in YBCO, as well as to determine the Co3+ spin-state in LaCoO3.
Student‐reported differences in technology use and skills after the implementation of one‐to‐one computing

This two‐year, mixed methods study with surveys, observations, and interviews, documented student technology use and skill before and after the implementation of a new one‐to‐one tablet computing program at a private middle school in the United States. After one year with tablets, several differences in students' technology use and skill were documented, including: higher satisfaction with school technology, greater frequency of technology use in specific subjects such as math and science, greater frequency of certain classroom activities such as two‐way communicating, and greater technology skills on competencies such as editing collaborative wikis. New modes of student collaboration were evident after implementing the tablet program, including sharing notes and co‐editing wikis. Differences were inconsistent across grade levels and subjects, suggesting teachers are adopting the tablet innovation differentially. In general, technology use increased most in math, science, and social studies classrooms, wi...
Uv resonance Raman spectroscopy of nucleic acid duplexes containing A-U and A-T base pairs

Resonance Raman spectra have been obtained at several uv wavelengths (200–266 nm) for poly(rA)-poly(rU), poly(dA-dU), poly(dA)-poly(dT), and poly(dA-dT), representing nucleic acid duplexes containing A-U and A-T base pairs with different stacking interactions and different backbone conformations. Frequency shifts are seen in the exocyclic modes corresponding to coupled C4O and C5C6 stretching of U and T, although the NH2 scissors frequency of A is unshifted relative to that of the mononucleotide. These frequency patterns are interpreted as the superposition of H bonding and dipole–dipole coupling effects. Strong hypochromism is seen for most of the ring modes, resulting from the absorption hypochromism and from shifts in the electronic transitions due to stacking. The effects are larger for A bands in the homopolymers than in the heteropolymer duplexes, reflecting the larger influence of A/A than A/U(T) stacking. Poly(rA)-poly(rU) stands out among these polymers in showing 10 cm−1 downshifts in one U and several A modes. These shifts may be related to the A form structural parameters of this duplex, but the physical mechanism is not obvious.
Myocardial perfusion: Contrast echocardiography perspectives

Contrast echocardiography may become a useful means of quantifying transmural regional myocardial perfusion patterns, experimentally and clinically, in a variety of settings. Contrast echocardiography has already been used in the operating room to study perfusion during coronary artery bypass graft (CABG) surgery. Other recent studies have demonstrated the ability of contrast echocardiography to predict wall motion improvement following acute myocardial infarction and therapeutic intervention. This is significant in the light of the discrepancy that has recently been shown between epicardial coronary vessel diameter and coronary flow. Studies suggest that both tissue and blood flow and volume may be quantitatively evaluated using contrast echocardiography, and these parameters ultimately may be used to assess tissue viability or vascular reserve. Contrast echocardiography techniques have been shown to be safe and reliable, and provide a high degree of spatial and temporal resolution.
Zinsight: a visual and analytic environment for exploring large event traces

Information in event traces from software systems can help developers with performance analysis, debuggingand troubleshooting. However, the volume of data contained in these traces can make such tasks a challenge. In this paper we propose a new tool, Zinsight, to visualize event traces from complex systems. Our contribution is a novel combination of visualizations and pattern extraction techniques, enabling user exploration, analysis and understanding of traces containing millions of events. Three complimentary views help the user answer different questions. First, the Event Flow view shows the trace in its entirety or in detail. The user sees visual patterns representing phases of processing and the relative order of events. Second, the Event Statistics view quantifies events, and presents distributions and averages enabling the user to identify outlier behavior. Third, the Sequence Context view extracts patterns of interest from the trace and represents them along with frequency and performance data in succinct execution flow diagrams. The user can navigate from patterns to their constituent instance sequences and even back to individual events in the other views. Questions can be answered and hypotheses tested using the most natural view for the task.
In Vitro Biotinylation Provides Quantitative Recovery of Highly Purified Active Lactose Permease in a Single Step

Consler et al. [Consler, T. G., Persson, B. L., et al. (1993) Proc. Natl. Acad. Sci. U.S.A. 90, 6934-6938] described a one-step purification of lactose permease, a hydrophobic membrane transport protein, from Escherichia coli. Permease constructs containing a biotin acceptor domain are biotinylated in vivo, followed by solubilization and avidin affinity purification. Although a high degree of purity is obtained, only about 15-20% of the permease is recovered due to incomplete biotinylation. In this communication, a simple modification is described that allows quantitative recovery of highly purified permease. Membranes containing permease with the biotin acceptor domain from the Klebsiella pneumoniae oxaloacetate decarboxylase are extracted with 5 M urea or treated with dicyclohexylcarbodiimide to inactivate F1/Fo ATPase and biotinylated in vitro with biotin ligase, ATP and d-biotin. Subsequently, the membranes are harvested, washed to remove free biotin and solubilized with 2% n-dodecyl-beta-D-maltopyranoside. Biotinylated permease is then purified in one step by affinity chromatography on monomeric avidin-Sepharose. The purified material is homogeneous and exhibits full activity with respect to ligand binding and counterflow.
Application of constrained equilibrium thermodynamics to irradiated alloy systems

Abstract Equilibrium thermodynamics are applied to systems with an excess of point defects to calculate the relative stability of phases. It is possible to model systems with supersaturation levels of vacancies and interstitials, such as those found under irradiation. The calculations reveal the extent to which phase compositional boundaries could shift when one phase or both in a two phase system contain an excess of point defects. Phase boundary shifts in the Ni-Si, Fe-Ni, Ni-Cr, and Fe-Cr systems are examined as a function of the number of excess defects in each phase. It is also found that the critical temperature of the sigma phase in the Fe-Cr system and the fcc-bcc transition in the Fe-Ni are sensitive to excess defect concentrations. These results may apply to local irradiation-induced phase transformations in the presence of solute segregation.
Collective Baha'i Identity Through Embodied Persecution: "Be ye the fingers of one hand, the members of one body"

Members of the Baha'i Faith have been subject to persecution in Iran since the mid-nineteenth century. Our investigation considers how collective identity among a Pacific Northwest Community has been constructed through the contexts of continued persecution in Iran and the development of religious texts, which helped to define the religious community. The texts found within the Baha'i Faith utilize metaphors of the body to construct religious identity. Many anthropologists have theorized on the usefulness of the body as a unit of study; in addition, recent attention by scholars has illustrated the intersection of the body and religion. A model is developed linking identity, consciousness, the body and experience that explains how collective identity is constructed. When considering the situation of the Baha'i community, this model has proven particularly useful in understanding how geographically disassociated people manage to construct social kinship within the context of religious persecution. In particular, American Baha'is describe the persecution of Baha'is in Iran as a collective experience, especially since the direct experience of persecution is far removed from their everyday living. Preliminary analysis of interviews with an American Baha'i, and an ex-patriot Iranian Baha'i reveal differences in constructions of identity.
Public bailouts, executive compensation and retention: A structural analysis

Abstract We study the effects of institutional constraints on incentive contracts by estimating a structural model of executive compensation and retention during financial crises. We use the model to analyze the effects of a cap on executive compensation for firms accepting public bailouts. Policy simulations include the following results. Estimated probabilities of bailout acceptance are low, suggesting that the costs to firms of accepting future constraints on executive pay are large. The policy reduces CEO retention rates, raises total compensation and firm profit, and distorts compensation contracts, yielding base pay (a slope) that is inefficiently low (high).
Google Scholar: the pros and the cons

Purpose – To identify the pros and the cons of Google Scholar.Design/methodology/approach – Chronicles the recent history of the Google Scholar search engine from its inception in November 2004 and critiques it with regard to its merits and demerits.Findings – Feels that there are massive content omissions presently but that, with future changes in its structure, Google Scholar will become an excellent free tool for scholarly information discovery and retrieval.Originality/value – Presents a useful analysis for potential users of the Google Scholar site.
Intercultural Communication: Finding Common Ground

Diversity has become a leading topic of discussion in virtually all sectors of our society. This is certainly true in health care; the nursing profession has long been dealing with issues of cultural appropriateness. This article looks at the relationship of culture to communication. The current approach to intercultural communication discussed in much of the nursing literature is judged to be short-sighted. An alternative approach based on the development of a functional cultural communication perspective is offered.
Prevention of Transfusion-Associated Graft-Versus-Host Disease by Inactivation of T Cells in Platelet Components

Patients with hematological malignancies and infants with congenital immunodeficiencies who received blood are two of many populations at risk for transfusion-associated graft-versus-host disease (TA-GVHD). Of the methodologies (eg, photoinactivation, peglyation, ultraviolet light, and irradiation) that can be used to prevent TA-GVHD, only irradiation of whole blood and cellular components is currently accepted practice of the US Food and Drug Administration (FDA). Among the newer methods that have been developed to reduce the risks of bacterial and viral contaminants of platelet transfusions, photochemical treatment (PCT) using psoralens and long-wavelength ultraviolet (UVA) irradiation modifies bacterial and viral genomes sufficiently to inhibit replication. Among a broad group of compounds, the synthetic psoralen compound amotosalen hydrochloride (HCl) (S-59) has been shown to be particularly effective in inactivating bacteria and viruses, without adversely affecting in vitro and in vivo platelet function.
Many Body Methods and Effective Field Theory

In the framework of pionless nucleon–nucleon effective field theory we study different approximation schemes for the nuclear many body problem. We consider, in particular, ladder diagrams constructed from particle–particle, hole–hole, and particle–hole pairs. We focus on the problem of finding a suitable starting point for perturbative calculations near the unitary limit (kFa)→∞ and (kFr)→0, where kF is the Fermi momentum, a is the scattering length and r is the effective range. We try to clarify the relationship between different classes of diagrams and the large g and large D approximations, where g is the fermion degeneracy and D is the number of space–time dimensions. In the large D limit we find that the energy per particle in the strongly interacting system is 1/2 the result for free fermions.
An Appetite for Activism: The Lesbian Avengers and the Queer Politics of Visibility

The Lesbian Avengers, an activist group of the early 1990s, utilized rhetorics of visibility to draw attention to lesbian issues, highlighting their gendered and sexualized bodies. Coinciding with the emergence of lesbian chic in popular culture, the Avengers complicated the bodily abstraction presumed in public discourse by flaunting a sexual excessiveness that could not be contained by a heteronormative economy of desire. Premised on displacement, the Avengers’ visibility therefore productively queers the politics of visibility.
The role of deformation temperature and strain on grain boundary engineering of Inconel 600

Abstract The present study investigates the effect of deformation temperature and strain on the formation of twin boundaries in Inconel 600. With a constant strain rate of 0.003/s, deformation temperatures were varied between 25 °C and 982 °C while strains varied between 11% and 80%. The resulting microstructures were characterized using electron back scatter diffraction both immediately following deformation and after an annealing cycle at 1025 °C. Comparison of the grain boundary characters associated with the samples enabled correlation of the processing parameters to the formation of desirable coherent twin boundaries and the identification of a deformation mechanism map. Processing parameters associated with strain annealing and dynamic recovery were found to promote the formation and retention of twin boundaries, while statically and dynamically recrystallized microstructures tend to contain large proportions of random grain boundaries that mitigate the effects of grain boundary engineering.
A Decision Procedure for Certain Abelian Varieties over Function Fields

Abstract We prove that there is a decision procedure for the additive group of isogenies between two abelian varieties over Q c ( t ), where Q c is the algebraic closure of the rational numbers. This procedure uses Falting′s isogeny theorem, a countable listing of possible isogenies for a sequence of lower bounds, and a calculation of Galois actions on the division points modulo m for increasing m for an upper bound. This gives a decision procedure for abelian varieties which become trivial over some finite extension field. We prove that a formula of Kodaira and Shioda for rank of general elliptic surfaces is valid for all abelian varieties over Q c ( t ) having no continuous family of sections, namely rank of numerical equivalence classes of 2-dimensional divisors modulo classes from fibres and the zero section. We also give a computable upper bound on the rank based on etale cohomology. It is equal to the rank if the Tate conjecture holds.
Earnings Inequality and the Changing Association between Spouses' Earnings.

Increases in the association between spouses' earnings have the potential to increase inequality as marriages increasingly consist of two high‐earning or two low‐earning partners. This article uses log‐linear models and data from the March Current Population Survey to describe trends in the association between spouses' earnings and estimate their contribution to growing earnings inequality among married couples from 1967 to 2005. The results indicate that increases in earnings inequality would have been about 25%–30% lower than observed in the absence of changes in the association, depending on the inequality measure used. Three components of these changes and how they vary across the earnings distribution are explored.
Maneuver-based autonomous navigation of a small fixed-wing UAV

An urban operation of unmanned aerial vehicles (UAVs) demands a high level of autonomy for tasks presented in a cluttered environment. While fixed-wing UAVs have been well suited for long-endurance missions at a high altitude, their navigation inside an urban area brings more challenges in motion planning and control. The inability to hover and low agility in motion cause more difficulties on planning a feasible path in a compact region, and a limited payload allows only low-grade sensors for state estimation and control.
Optimal foldover plans for blocked 2m-k fractional factorial designs

Abstract In many experimental settings, an initial two-level fractional factorial design is run to determine which experimental factors are significant. A follow-up design is then run to further explore relationships such as interactions that might exist between experimental factors. A commonly used follow-up strategy involves the use of a foldover design which is obtained by reversing the signs of one or more columns in the design matrix of the initial design. The full design obtained by joining the runs in the follow-up design to those of the initial design is called the combined design. In this paper we explore the use of the foldover technique as applied to blocked regular fractional factorial designs. In particular, two criteria are suggested for finding optimal foldover plans. The two criteria suggested are a minimum aberration criterion and a maximal rank-minimum aberration criterion as applied to the combined designs which can be obtained by using different foldovers of the initial design. Using these criteria and search methods, optimal foldover plans are obtained for each of the blocked fractional factorial plans given in Sun, Wu and Chen [1997. Optimal blocking schemes for 2 n and 2 n - p designs. Technometrics 39, 298–307] having nine or fewer factors. Tables containing these optimal foldover plans are given in the Appendix.
Effect of oxygen on the stability of one dimensional long period superstructures in Cu3Pd

This paper reports that high resolution electron microscopy (HREM) studies of Cu-Pd alloys have revealed that the antiphase boundaries (APB), associated with the LPS formed at low temperatures, exhibit a sharp character, while those in LPS equilibrated at high temperatures are diffuse (the diffuse character of APBs can be ascribed to disorder along the boundary or to small fluctuations of the positions of the APB). In a recent theoretical study, sharp and diffuse characters of APB at various temperatures were attributed to flat sections on the Fermi surface of Cu-Pd alloys, which produce a deep minimum in V(k), the Fourier transform of the effective pair interactions: At high temperature, the deep minimum in V(k) quickly diminishes the amplitude of the Fourier components of the modulation wave that are located away from the V(k) minimum, which leads to a smooth modulation profile. Consequently, in selected area diffraction patterns (SAD), only first order satellites are expected. On the other hand, at lower temperatures, where the contribution from the Fourier component of the modulation wave away from the minimum in V(k) is also significant, higher order satellites should be observable in SAD patterns. These prediction agree with experimental results.
Finite element model simulations associated with hydraulic fracturing

This study presents methodology and results pertinent to hydraulic fracture modeling for the U.S. DOE's Eastern Gas Shales Program (EGSP). The presented finite-element model simulations extend available modeling efforts and provide a unified framework for evaluation of fracture dimensions and associated responses. Examples illustrating the role of multilayering, in-situ stress, joint interaction, and branched cracks are given. Selected comparisons and applications also are discussed. 30 refs.
Occurrence of the Ascochyta blight pathogen, Ascochyta lentis, on lentil seed in Bolivia

Ascochyta lentis was isolated from necrotic lesions on lentil seed purchased in commercial markets throughout Bolivia in 2000. Incidence of seed infection ranged from 1% to 34% and the fungi isolated were able to reinfect lentil foliage in artificial inoculations. Disease spread from seed to seedling in the field was confirmed by planting infected seed in a field previously free of the disease and observing Ascochyta blight on the foliage. In addition, disease spread between plants initiated from infected seedlots to those initiated from clean seedlots and from infected plants back to seed was also detected. These observations indicate that A. lentis infection of lentil seed is common in Bolivia and may represent an important inoculum source for Ascochyta blight epidemics in commercial lentil plantings.
Data refinement of mixed specifications

Using predicate transformers as a basis, we give semantics and refinement rules for mixed specifications that allow UNITY style specifications to be written as a combination of abstract program and temporal properties. From the point of view of the programmer, mixed specifications may be considered a generalization of the UNITY specification notation to allow safety properties to be specified by abstract programs in addition to temporal properties. Alternatively, mixed specifications may be viewed as a generalization of the UNITY programming notation to allow arbitrary safety and progress properties in a generalized ‘always section’. The UNITY substitution axiom is handled in a novel way by replacing it with a refinement rule. The predicate transformers foundation allows known techniques for algorithmic and data-refinement for weakest precondition based programming to be applied to both safety and progress properties. In this paper, we define the predicate transformer based specifications, specialize the refinement techniques to them, demonstrate soundness, and illustrate the approach with a substantial example.
Electron attraction and Newtonian methodology for approximating quantum mechanical phenomena

Abstract Classical dynamical computations for ground state H 2 2 , H 2 1 , H 2 3 , H 1 , H 2 , H 1 , H 3 , Li 2 7 , B 2 9 , C 2 12 and N 2 14 have been shown to yield correct vibrational frequencies and molecular diameters under an assumption of electron attraction for bonding electrons. In this paper, it is shown that such a mechanism also extends to O 2 16 and to the nonhomogeneous molecules Li 7 H 1 and Li 7 H 2 . The vibrational motions are, apparently, quasi-periodic rather than periodic.
Systemic or Local Administration of Azide Produces Striatal Lesions by an Energy Impairment-Induced Excitotoxic Mechanism

Sodium azide is an inhibitor of cytochrome oxidase which produces selective striatal lesions in both rodents and primates. In the present study we investigated the neurochemical and histologic effects of both intrastriatal and systemic administration of sodium azide, as well as the age dependence and mechanism of the lesions. Intrastriatal administration of sodium azide produced dose-dependent lesions. Neurochemical and histologic evaluation showed that markers of both spiny projection neurons (GABA, substance P) and aspiny interneurons (somatostatin, neuropeptide Y, NADPH-diaphorase) were equally affected. Subacute systemic administration of sodium azide resulted in lesions with a similar neurochemical profile; however, in contrast to intrastriatal injections there was sparing of dopaminergic striatal afferents. Prior decortication significantly attenuated lesions produced by intrastriatal administration of sodium azide, consistent with an excitotoxic process. Chronic administration of sodium azide for 1 month lead to striatal neuropathological changes. Lesions produced by intrastriatal administration of sodium azide in 1-, 4-, and 12-month-old animals showed age dependence. Both freeze-clamp measurements and chemical-shift magnetic resonance spectroscopy confirmed that sodium azide impairs oxidative phosphorylation in the striatum following either intrastriatal or systemic administration. These results show that the striatum is particularly vulnerable to oxidative stress produced by sodium azide, and that it produces striatal lesions by a secondary excitotoxic mechanism.
Protocol design considerations that relate to demonstrating the safety and effectiveness of chemopreventive agents.

As with other drugs, applications for marketing approval of new chemopreventive agents in the United States must include data from adequate and well-controlled clinical trials that demonstrate effectiveness and safety for the intended use. Knowledge of a drug's pharmacologic actions and metabolism may benefit protocol design, by identifying the patient populations and dosing schedules associated with a favorable risk/benefit profile. With availability of appropriate preclinical data, including standard assessments of an agent's toxicology, effects on reproductive performance, and genotoxicity, initial Phase I studies of 1–3 months may be performed in normal volunteers or an appropriate higher-risk population. For chronic dosing studies of longer duration, preclinical toxicology studies of longer duration are relevant. Enrollment in chemoprevention studies should be directed toward individuals at sufficient risk of developing cancer so that potential benefit may counterbalance the unpredictable and possibly serious adverse effects that may be observed with prolonged administration of a study drug. Phase I and II studies with clinical dosing lasting up to 12 months often afford opportunities to assess drug effect on surrogate endpoint biomarkers that may correlate with endpoints of clinical effectiveness. Phase III and late phase II chemopreventive investigations should routinely utilize a prospective, randomized study design (double-masked and placebo-controlled, when possible). To support marketing approval, there must be evidence that a chemopreventive agent significantly delays or prevents the occurrence of malignancy, with acceptable safety. In some circumstances, modulation of a surrogate marker may provide a basis for marketing approval, before more definitive endpoint data become available. However, the acceptability of a surrogate depends on the nature and quality of the data supporting its predictive value. Given the considerations of large study size, long duration, and high cost that may hamper development of potential agents, studies designed to examine the predictive value of surrogate endpoint biomarkers are of great importance to the future development of chemoprevention research. J. Cell. Biochem. Suppl. 27:1–6. Published 1998 Wiley-Liss, Inc.
On balanced signed graphs and consistent marked graphs

Abstract Data in the social sciences can often be modeled using signed graphs , graphs where every edge has a sign + or −, or marked graphs , graphs where every vertex has a sign + or −. We study balanced signed graphs, those where every cycle has an even number of − edges, and consistent marked graphs, those where every cycle has an even number of − vertices. We survey motivation for and applications of these concepts and characterizations of balance and consistency.
Microstructure determination of cement pastes by NMR and conventional techniques

Applicability of NMR relaxation analysis to the characterization of pore structure in hydrating white cement pastes has been investigated. Measurements of transverse magnetization relaxation were made in specimens saturated and partially filled with water for periods of hydration between 1 and 28 days. The fast diffusion model successfully accounts for all relaxation measurements. The transverse surface relaxation rate was determined. A two-component pore volume size distribution was found. Comparison was made with mercury porosimetry and nitrogen sorption experiments and the results were correlated with compressive strength.
Schedule interactions in second-order fixed-interval (fixed-ratio) schedules of token reinforcement☆

Abstract Three rats performed in an extended behavior sequence in which lever pressing was maintained on an FR 20 schedule of token reinforcement. Fixed-interval exchange schedules were varied from FI 1.5 min to FI 9.0 min, and during exchange the schedule of food reinforcement was FR 1. The FR 20 schedule of token reinforcement and the FI exchange schedules interacted to produce patterns of responding appropriate to each schedule. Overall response rates declined as the FI exchange schedule was increased in duration. The general token reinforcement paradigm was discussed in terms of its similarities with the chained schedule paradigm and the secondorder schedule paradigm with brief-stimulus presentations.
Polymerization of 2-allyl-1-methylenecyclohexane by the cyclic polymerization mechanism

2-Ally-1-methylenecyclohexane is a compound which is functionally capable of undergoing polymerization by the alternating intra-intermolecular propagation mechanism to produce poly[1,8-methylene[4.3.0] bicyclononane]. This monomer was synthesized and its polymerization through use of cationic and Ziegler-type initiators was studied. Synthesis of the monomer was accomplished by the following reaction sequence: (1) conversion of cyclohexanone to 2-allycyelohexanone by reaction wtih allyl bromide and sodium amide and (2) conversion of 2-allycyclohexanone to the desired monomer by reaction with the phosphorane derived from methyltriphenylphosphonium bromide. Polymerizaton was accomplished by use of boron trifluoride resulting in 44% conversion to polymer, of which 94% was soluble. Through use of infrared and nuclear magnetic resonance techniques, the soluble portion of the polymer was shown to contain 54% of bicyclic units and the remainder to be non-cyelized monomer units in which the residual unsaturation was composed predominantly of allyl groups.
A p -version finite element formulation for analyzing infinitely wide gas bearing problems

Abstract Steady-state compressible lubrication solutions are revisited. In this paper, problems with gas bearings of infinite width are formulated by the p -version finite element method ( p -FEM) in conjunction with the Newton-Raphson iteration procedure. Numerical examples show that the current p -FE formulation is an accurate FE scheme for solving compressible lubrication problems, and that, even for high bearing number cases (Λ > 1000) and coarse grids, the scheme converges rapidly.
Integral method of analysis for chemical reaction in a nonisothermal finite cylindrical catalyst pellet-II. Robin problem

The problem of diffusion and reaction on a porous nonisothermal finite cylindrical catalyst pellet in the presence of external heat and mass-transfer resistances is solved by the integral equation method. The modified Green's function method developed previously (Mukkavilli et al., 1987, Chem. Engng Sci., 42, 27–33) is extended to transform the partial differential equation into a Fredholm integral equation and to accelerate the convergence of the partial eigen series by an order of two. The Prater relation, expressing the pellet temperature as a linear function of concentration, is used under two simplifying assumptions: (i) the Nusselt and Sherwood numbers are equal; or (ii) the surface concentration is invariant. The resulting integral equation is solved to obtain effectiveness factors for various nonlinear reaction rate forms. This is the first study to report effectiveness factors for the commonly used finite cylindrical catalyst pellet geometry for the important case of internal and external resistances.
Pulsatility of luteinizing hormone during puberty is dependent on recent glycemie control

Abstract We prospectively studied an adolescent girl with insulin-dependent diabetes over a 22-month period. She initially presented with poor glycemie control and arrested pubertal development. Despite an immature luteinizing hormone (LH) secretory profile, she exhibited a mature LH response to injection of a bolus of synthetic gonado-tropin-releasing hormone (GnRH) at the time of initial evaluation. Improvement of her glycemic control was associated with maturation of LH pulsatility, improved estrogen production, and menarche. Subsequent deterioration of her glycemic control resulted in immaturity of pulsatile LH secretory pattern, whereas her response to GnRH remained mature. We hypothesize that the ovarian hypo-function observed was due to inhibition of the hypothalamic GnRH pulse generator and was influenced by the prevailing level of glycemia. In all cases, short-term glycemic control (as measured by fructosamine) was a better predictor of hormonal secretion than was long-term glycemic control (as measured by glycohemoglobin).
Lunar tidal effects in the electrodynamics of the low latitude ionosphere

Abstract The low latitude ionosphere is highly variable over a large range of temporal and spatial scales even during geomagnetically quiet periods, largely as a result of electrodynamic plasma drift effects. Several recent experimental and modeling studies have investigated the electrodynamic response of the low latitude ionosphere to high latitude and lower atmospheric wave activity, particularly during sudden stratospheric warmings. In this work, we review some recent results on the short-term variability of equatorial vertical plasma drifts measured mostly at the Jicamarca Radio Observatory and their effects on equatorial short-scale spread F irregularities. We show that lunar tidal semidiurnal and diurnal effects, which have been largely ignored in most studies, can play significant roles in low latitude ionospheric variability.
Molecular dynamics simulations of inelastic energy loss effects in sputtering II

Previous molecular dynamics (MD) simulations of inelastic energy loss effects in sputtering, which have employed pair potentials and velocity-dependent losses, have attributed significant reductions in sputtering yield (up to 40%) to energy losses in atom-atom collisions. Similar simulations in which the average electron density is replaced by the local electron density as calculated from the embedded-atom method (EAM) and Thomas-Fermi local electron densities also yield significant inelastic energy losses in the collision cascade [A. Caro and M. Victoria, Phys. Rev. A 40 (1989) 2287]. Here we report results of EAM MD inelastic energy loss simulations for the Ar^+-Cu system for bombarding energies from 1 keV to 5 keV using a model that includes velocity-dependent losses for collisions with valence electrons and instantaneous losses for collisions involving core electrons. With this model we find that losses attributable to collisions with valence electrons and atom-atom collisions involving core electrons produce negligible reductions in sputtering yield. The inclusion of instantaneous losses from ion-atom collisions, however, produces significant reductions in sputtering yield above a bombarding energy threshold of approximately 2 keV. The polar-angle distributions of atoms sputtered from the Cu(100) surface also are changed significantly by this inelastic loss model.
A coupled spectrophotometric assay for l-cysteine:1-d-myo-inosityl 2-amino-2-deoxy-α-d-glucopyranoside ligase and its application for inhibitor screening

Abstract Most actinomycetes, including Mycobacterium tuberculosis , do not produce glutathione but make an alternative thiol, mycothiol, which has functions similar to those of glutathione. A key step in mycothiol biosynthesis is the ATP-dependent ligation of Cys to GlcN-Ins catalyzed by MshC to produce Cys-GlcN-Ins, AMP, and PP i . MshC is essential for growth of M. tuberculosis and is therefore a potential target for drugs directed against tuberculosis. A coupled-enzyme assay for MshC was developed using pyrophosphatase to convert pyrophosphate to phosphate and spectrophotometric detection of the latter via the phosphomolybdate complex with malachite green. The assay was readily adapted for use in a 96-well microtiter plate format. A secondary high-performance liquid chromatography assay measuring Cys-GlcN-Ins production was used to validate potential hits. Preliminary testing on a library of 2024 compounds predicted to inhibit ATP-dependent enzymes identified many promiscuous and pyrophosphatase inhibitors of MshC and a single validated inhibitor with IC 50 ∼ 100 μM.
MAX3SAT is exponentially hard to approximate if NP has positive dimension

Under the hypothesis that NP has positive p-dimension, we prove that any approximation algorithm A for MAX3SAT must satisfy at least one of the following: 1. For some δ > 0, A uses at least 2nδ time. 2. For all e > 0, A has performance ratio less than 7/8 + e on an exponentially dense set of satisfiable instances. As a corollary, this solves one of Lutz and Mayordomo's "Twelve problems on resource-bounded measure" (Bull. European Assoc. Theoret. Comput. Sci. 68 (1999) 64-80).
Measurements of ice water content in tropopause region Arctic cirrus during the SAGE III Ozone Loss and Validation Experiment (SOLVE)

[1] A new instrument, the closed-path laser hygrometer (CLH), was flown on the NASA DC-8 aircraft during the Stratospheric Aerosol and Gas Experiment (SAGE) III Ozone Loss and Validation Experiment (SOLVE) campaign in 1999–2000 to measure condensed-phase water. The ice water content (IWC) of Arctic cirrus was determined from in situ measurements of condensed- and gas-phase water. The IWC values obtained from the CLH observations are compared to those determined by integrating particle size distributions measured by a Forward Scattering Spectrometer Probe (FSSP) also flown on the DC-8. The considerably greater IWC seen by the CLH implies the presence of particles with diameters greater than the FSSP's upper limit of 20 μm. The evidence for and implications of the presence of large ice crystals in Arctic cirrus is discussed.
Reducing uric acid as a means to prevent cardiovascular and renal disease

Hyperuricaemia (uric acid levels > 6.5mg/dl in men and > 6.0 mg/dl in women) affects ~ 10% of the population but is not classically treated with uric acid-lowering drugs unless there is a history of gout or uric acid renal stones. However, there is strong epidemiological evidence that hyperuricaemia is associated with cardiovascular and renal disease. It has recently been shown that mild hyperuricaemia in rats causes hypertension, vascular disease and renal injury and that lowering uric acid levels can prevent these complications. Thus, there is renewed interest in current and future therapies that may be used to lower uric acid. This paper reviews current therapies, particularly the xanthine oxidase inhibitors and uricosuric agents, as well as novel approaches to uric acid reduction, such as replacement enzyme therapies.
Indiana chronic disease management program risk stratification analysis.

Objective:The objective of this study was to compare the ability of risk stratification models derived from administrative data to classify groups of patients for enrollment in a tailored chronic disease management program.Subjects:This study included 19,548 Medicaid patients with chronic heart fail