cssi/SciSciGPT-SciSciNet huggingface dataset:
Atomistic characterization of the Cu–Pb solid–liquid interface

Abstract Using an embedded atom model (EAM) and molecular-dynamics simulation, we examine the equilibrium interface between solid Cu and liquid Pb at a temperature just above the melting point of Pb (625 K). This chemically heterogeneous solid–liquid interface is characterized by the calculation of density, stress, potential energy and diffusion constant profiles, as well as by a two-dimensional Fourier analysis of the interfacial layers for two different interfacial orientations relative to the Cu lattice: (1 0 0) and (1 1 1). For the (1 0 0) orientation, we observe significant surface alloying in the first interfacial layer, consistent with earlier investigations by Webb et al. (Phys. Rev. Lett. 91, 236102 (2003)). No interfacial alloying is seen in the (1 1 1) direction; however, a “prefreezing” layer of crystalline Pb, approximately 2–3 lattice planes in thickness, is observed to form at the (1 1 1) Cu interface at 625 K. The lattice planes in this prefreezing layer are hexagonal with a lattice spacing that is 33% larger than that of the bulk Cu crystal substrate but 1.9% smaller than that expected for bulk crystalline Pb at 625 K. The prefreezing layers are also rotated by an angle of 6° relative to the underlying Cu(1 1 1) surface.
Next Generation Navy Ship Automation Systems Engineering From Sensors to Systems

The next generation navy ship acquisition strategy calls for the delivery of an entire system of interoperable combat and machinery platforms with supporting systems designed to meet performance-based requirements. Many systems will operate various parts of the ship, but the ship functions optimally when all its systems work properly together. For the ship function, it needs to have the right mix of these independent systems, and these systems need to cooperate with each other. This emerging "system of systems" concept involves the large-scale integration of many independent, self-contained systems in order to satisfy a global need. For Navy ships, these complex multi-systems are very interdependent. To properly design, build and integrate a system of systems type of automation suite requires a new systems engineering approach
Exclusive-OR representations of Boolean functions

With the goal of making exclusive-OR formulations of switching functions more readily available to designers for implementation in LSI and VLSI technologies, we introduce the concept of an exclusive-OR space in which an exclusive-OR normal form is defined to correspond to the conventional disjunctive normal form. A geometrical representation of exclusive-OR space is described, and its various bases are listed and discussed.
Convergence of the method of fundamental solutions for solving the boundary value problem of modified Helmholtz equation

In this paper we derive the rate of convergence for the method of fundamental methods in solving the boundary value problem of a homogeneous modified Helmholtz equation. By using the Fourier sine expansion to find particular solutions we establish the convergence results for solving the boundary value problem of a non-homogeneous equation.
Effect of the chemical and physical properties of carbon black on its performance in polyethylene

A comprehensive study of the performance of various types of carbon black in polyethylene has been made. The physical and chemical properties of carbon blacks are discussed, and the effectiveness of various blacks as ultraviolet screening agents for polyethylene is assessed. It is seen as a first approximation that primary particle size is the property of the carbon black which largely governs the weatherability of a compound. The data suggest that this is due to that fact that the degree of ultraviolet protection is dependent on the presence of submicroscopic aggregates and their distribution throughout the polymer mass. It is proposed that the aggregate size and distribution are largely controlled by the surface energy arising from the dimensions of the primary particles. Studies of carbon black-antioxidant systems gave results which were in agreement with those of Hawkins et al., who found that carbon blacks having a polar surface exhibit a synergistic behavior with organosulfur type antioxidant, greatly increasing the time required to absorb a given amount of oxygen or undergo thermal degradation. The present study shows that use of antioxidants also contributes to the ability of polyethylene compounds to resist accelerated aging. Outdoor aging of the same compounds are in progress, but more time is required to see if antioxidants are helpful in the manner indicated by the accelerated weathering studies. The effect of carbon blacks on the mechanical properties of polyethylene is discussed, and data are presented to show that higher loadings of carbon black than normally used for ultraviolet protection greatly increase the tensile yield (stress at draw point) at relatively fast rates of applied stress. It is suggested that the use of moderately high concentrations of carbon black would enhance the performance of polyethylene in applications such as pipe which often fails under rapidly applied stress.
Static Universe in a Modified Brans-Dicke Cosmology

We derive a static model of the universe, where density and pressure are constant, but the gravitational “constant” and the cosmological term vary with time, by means of the Endo-Fukui modified Brans-Dicke theory.
The sterols of normal and male-sterile maize tassels during development

Abstract The steroids of normal and male-sterile (Texas type) genotypes of maize were investigated during tassel development. A bioassay for estrogen activity of the normal meiotic and postmeiotic tassels was negative, indicating estrogen activity (estrone equivalent) much less than one ng/g of plant tissue. The sterols found were cholesterol, campesterol, stigmasterol, sitosterol, and probably isofucosterol, stigmast-7-enol, and 24-methylenecholesterol. In the premeiotic, meiotic, and postmeiotic stages of both genotypes between 300 and 400 μg of C 28 and C 29 free sterols per g tassels (wet wt) were found, the proportions of the sterols being ca 45% sitosterol, 30% stigmasterol, and 13% campesterol, with less than 5% each of the remaining sterols. In all three stages before saponification more free sterols were found in the normal than in the male-sterile tassels. The differences were significant at the 95% level in the meiotic and post-meiotic stages. The amounts of these sterols derived from esters decreased from approximately 140 μg/g in the premeiotic stage to 50 μg/g in the meiotic stage, and to an undetectable amount in the postmeiotic stage. After application of cholesterol-[4- 14 C] to the normal and male-sterile maize leaves for 3 days at meiosis, the label was found in the free sterols and steryl esters of the leaves but only in the free sterols of the tassels.
Accumulation of urea by a pulmonate snail during aestivation

Abstract 1. 1. During normal feeding activity urea is usually undetectable in Bulimulus dealbatus, but with dormancy urea accumulates much faster than uric acid and to tissue levels of 260 μm/g wet wt. 2. 2. Since the incorporation rates of 14C-bicarbonate into urea and the activities of the ornithine-urea cycle enzymes are similar in active and aestivating snails, Bulimulus appears always to biosynthesize some urea. 3. 3. The build-up of urea probably results from cessation of urination during aestivation and may be important in reducing evaporative water loss. The ornithine cycle clearly is an important metabolic pathway in this snail.
Developing grain boundary diagrams for multicomponent alloys

Abstract Impurity-based, premelting-like, intergranular films (IGFs, a common type of grain boundary complexion) can form in various materials and influence sintering, creep, and microstructure development. A thermodynamic framework is presented to forecast the formation and stability of these premelting-like grain boundary complexions (a.k.a. interfacial “phases” that are thermodynamically two dimensional) in multicomponent alloys to consider the interactions of multiple alloying elements. Key thermodynamic parameters that control the interfacial segregation and disordering behaviors have been identified and systematically examined. Subsequently, ternary and quaternary grain boundary diagrams have been computed and used to forecast the sintering behaviors of W–Ni–M (M = Fe, Co, Cr, Zr, Nb and Ti) and Mo–Si–B–M (M = Ni, Co and Fe) systems. This work supports a long-range scientific goal of extending bulk computational thermodynamics and CALPHAD methods to interfaces and developing grain boundary complexion (interfacial “phase”) diagrams as extensions to bulk phase diagrams, which can be a generally useful materials science tool.
Interstellar chemistry: polycyanoacetylene formation

It is argued that interstellar polycyanoacetylenes are formed not on dust grains by catalytic buildup or by dissociation of longer molecules, but rather by gas phase ion-molecule reactions. The primary evidence for this view is the detection of deuterated cyanoacetylene in an interstellar cloud. It is also argued that the relative abundance of successive homologs of polycyanoacetylenes rules out the grain catalysis theory.
Efficient incremental algorithms for the sparse resultant and the mixed volume

Abstract We propose a new and efficient algorithm for computing the sparse resultant of a system of n + 1 polynomial equations in n unknowns. This algorithm produces a matrix whose entries are coefficients of the given polynomials and is typically smaller than the matrices obtained by previous approaches. The matrix determinant is a non-trivial multiple of the sparse resultant from which the sparse resultant itself can be recovered. The algorithm is incremental in the sense that successively larger matrices are constructed until one is found with the above properties. For multigraded systems, the new algorithm produces optimal matrices, i.e. expresses the sparse resultant as a single determinant. An implementation of the algorithm is described and experimental results are presented. In addition, we propose an efficient algorithm for computing the mixed volume of n polynomials in n variables. This computation provides an upper bound on the number of common isolated roots. A publicly available implementation of the algorithm is presented and empirical results are reported which suggest that it is the fastest mixed volume code to date.
Radiative interactions in a hydrogen-fueled supersonic combustor

The two-dimensional, elliptic Navier-Stokes equations are used to investigate supersonic flows with finite-rate chemistry and radiation, for hydrogen-air systems. The chemistry source term in the species equation is treated implicitly to alleviate the stiffness associated with fast reactions. The explicit, unsplit MacCormack finite-difference scheme is used to advance the governing equations in time, until convergence is achieved. The specific problem considered is the premixed flow in a channel with a 10-deg compression ramp. Three different chemistry models are used, accounting for increasing number of reactions and participating species. Two chemistry models assume nitrogen as inert, while the third model accounts for nitrogen reactions and NO(x) formation. The tangent slab approximation is used in the radiative flux formulation. A pseudogray model is used to represent the absorption-emission characteristics of the participating species. Results otained for specific conditions indicate that the radiative interactions vary substantially, depending on reactions involving HO2 and NO species, and that this can have a significant influence on the flowfield.
Combined use of an immunotoxin and cyclosporine to prevent both activated and quiescent peripheral blood T cells from producing type 1 human immunodeficiency virus.

Abstract Two different populations of infected T cells are present in human immunodeficiency virus (HIV)-infected individuals: activated cells that produce virions and quiescent cells that harbor the viral genome but are unable to produce virus unless they are activated. Using an in vitro model of acute HIV infection, we have evaluated the effect of depleting activated T cells with an immunotoxin and subsequently inhibiting activation of quiescent T cells with an immunosuppressive agent. CD25 (Tac, p55), the alpha chain of the interleukin 2 receptor, is expressed on activated, but not quiescent, T cells. An anti-CD25-ricin A chain immunotoxin eliminated activated, CD25+ HIV-infected cells and, thereby, inhibited viral production by these cells. Subsequent addition of cyclosporine to the residual CD25- cells prevented their activation and thereby suppressed their ability to produce virus and to propagate the infection to uninfected T cells.
Precipitate strengthening in nanostructured metallic material composites

Nanostructured metallic material (NMM) composites are a new class of materials that exhibit high structural stability, mechanical strength, high ductility, toughness and resistance to fracture and fatigue; these properties suggest that these materials can play a leading role in the future micromechanical devices. However, before those materials are put into service in any significant applications, many important fundamental issues remain to be understood. Among them, is the question of the strengthening of NMM using second phase particles and if the addition of precipitates will strengthen the structures in the same manner as in bulk crystalline solids. This issue is addressed in this work by performing molecular dynamics simulations on NMM with precipitates of various sizes and comparing the results with the same structure without precipitates. In this view, Cu/Nb bilayer thin films with spherical Nb particles inside the Cu layer were examined using molecular dynamics simulations and show a significant i...
Cytoplasmic Abnormalities in Monocytes From Patients With AIDS

This report describes cytoplasmic abnormalities in monocytes from patients with AIDS. Visualized on Wright-stained peripheral blood smears, these abnormalities were not found in normal monocytes, monocytes from patients receiving chemotherapy, monocytes from patients with monocytosis related to non-HIV viral or bacterial infection, or monocytes from patients with monocytic leukemia (French-American-British [FAB] classification M4 or M5). The cytoplasmic abnormalities were detected on panoptically stained blood smears using an ordinary light microscope. As such, a medical technologist and pathologist can detect them as a part of reviewing peripheral blood specimens that are flagged by modern hematology analyzers. Materials and Methods As enumerated in [T1], from a total of 275 samples of peripheral venous blood samples anticoagulated with EDTA (no more than 2 hours old), peripheral blood smears were made in an automated slidemaker-stainer (Sysmex M) and stained with a modified Wright stain. In the study, 82 of the 275 samples were obtained from patients who were HIV positive by Western blot. Other samples used as controls for the study were not subjected to Western blot analysis. At the time that blood smears obtained from these samples underwent microscopic review, this author was aware that they were HIV positive. From all 82 patients, simultaneous samples were obtained for flow cytometry. At the time that the blood smears were being reviewed microscopically, the author was not aware of the CD4 values of the blood samples from which the slides were made. Of the 82 HIV-positive patients, 34 had CD4 counts less than 200/μL (0.2 × 109/L) and fit the current definition for AIDS.1 In 48 patients with abnormal lymphocyte subsets, CD4 counts were greater than 200/μL (0.2 × 109/L). For controls, blood smears were obtained from 66 hematologically normal persons and from 43 patients whose peripheral blood specimens were flagged by the analyzer for monocytosis (monocytes 2,000/μL [0.2 × 109/L] or greater). For HIV testing [cytology | hematology | immunology | virology] Cytoplasmic Abnormalities in Monocytes From Patients With AIDS
USING COMPARATIVE GENOMIC DATA TO TEST FOR FAST-X EVOLUTION

Genes may acquire nonsynonymous substitutions more rapidly when X-linked than when autosomal, but evidence for "fast-X evolution" has been elusive. Fast-X evolution could explain the disproportionate contribution of X-linked genes to hybrid sterility and other traits. Here, we use a comparative genomic approach, with sequences of 30-110 genes in four Drosophila species, to test for fast-X evolution. Specifically, the 3L autosome arm in D. melanogaster and D. simulans is homologous to the right arm of the X chromosome in D. pseudoobscura and D. miranda. We executed two paired comparisons to determine how often genes on this chromosome arm exhibit higher rates of nonsynonymous substitution in the D. pseudoobscura species group, as predicted by fast-X evolution. We found a statistically significant pattern consistent with fast-X evolution in one comparison and a similar trend in the other comparison. Variation in functional constraints across genes may have masked the signature of fast-X evolution in some previous studies, and we conclude paired comparisons are more powerful for examining rates of evolution of genes when X-linked over autosomal.
Imitating success: a memetic crossover operator for genetic programming

For some problem domains, the evaluation of individuals is significantly more expensive than the other steps in the evolutionary process. Minimizing these evaluations is vital if we want to make genetic programming a viable strategy. In order to minimize the required evaluations, we need to maximize the amount learned from each evaluation. To accomplish this, we introduce a new crossover operator for genetic programming, memetic crossover that allows individuals to imitate the observed success of others. An individual that has done poorly in some parts of the problem may then imitate an individual that did well on those same parts. This results in an intelligent search of the feature-space, and therefore fewer evaluations.
Preventive PCI versus culprit lesion stenting during primary PCI in acute STEMI: a systematic review and meta-analysis.

Aim The benefit of preventive percutaneous coronary intervention (PCI) in ST elevation myocardial infarction (STEMI) has been shown in randomised trials. However, all the randomised trials are underpowered to detect benefit in cardiac death. We aim to systematically review evidence on the cardiac mortality benefit of preventive PCI in patients presenting with acute STEMI in randomised patient populations. Methods PubMed, Scopus, Cochrane and clinicaltrials.gov databases were searched for studies published until 30 September 2013. The studies were limited to randomised clinical trials. Independent observers abstracted the data on outcomes, characteristics and qualities of studies included. Fixed effect model was employed for meta-analysis. Heterogeneity of studies included was analysed using I 2 statistics. Results In three randomised clinical trials published, involving 748 patients with acute STEMI and multivessel disease, 416 patients were randomised to preventive PCI and 332 to culprit-only PCI. Patients undergoing preventive PCI had significant lower risk of cardiovascular deaths (pooled OR 0.39, 95% CI 0.18 to 0.83, p=0.01, I 2 =0%), repeat revascularisation (pooled OR 0.28, 95% CI 0.18 to 0.44, p=0.00001, I 2 =0%) and non-fatal myocardial infarction (pooled OR 0.38, 95% CI 0.20 to 0.75, p=0.005, I 2 =0%) compared with culprit-only revascularisation. Conclusions In patients presenting with acute STEMI and significant multivessel coronary artery disease, based on our data, preventive PCI is associated with lower risk of cardiovascular mortality compared with primary PCI of only the culprit artery. This finding needs to be confirmed in larger adequately powered randomised clinical trials.
Finite-Source Modeling of the 1999 Taiwan (Chi-Chi) Earthquake Derived from a Dense Strong-Motion Network

The 1999 Chi-Chi earthquake (M W 7.6) (20 September 1999, 17:47:15.9 UTC) (located at 23.853 N, 120.816 E, and depth of 7.5 km) inicted severe re- gional scale damage to Taiwan. The strong-motion waveeld was captured by a dense network of stations (with average station spacing of 5 km), which represents the most complete strong-motion dataset to date to use to study the kinematic source process of an earthquake. We inverted velocity waveforms recorded by 21 stations for the spatial variation in slip on a planar fault model composed of 416 subfaults, each with a dimension of 3.5 km by 3.5 km. The planar model has a strike of N5 E and a dip of 30 E, and the inversion solves for the direction and magnitude of the slip. To account for possible temporal source complexity we allowed each subfault to slip within 10 overlapping time windows, each with a duration of 3 sec. The results show that the source is composed primarily of three major asperities, the rst of which is mainly dip slip, extending from the hypocenter to the northern end of the surface rupture. In this asperity, slip occurred in two pulses separated in time by 5 sec. The dislocation rise time for each pulse is short (3n4 sec), yielding an approximate av- erage slip velocity of 80 cm/sec. The second asperity is located at shallow depth near the northern end of the rupture where very large ground velocities were observed. This asperity is on average oblique and shows a temporal rake rotation from pure dip-slip to strike-slip. The rotating rake suggests a low initial shear-stress on the northern end of the fault. Slip in this asperity is dominated by a large pulse with a dislocation rise time of 8 sec. A station near the northern end of the surface rupture recorded a peak velocity of 390 cm/sec, which we nd to be due to the constructive interference of energy radiated from the rst two asperities. The third asperity is located south of the epicenter. The total moment from the three asperities is 4.1 10 27 dyne cm, which was released over a period of 30n35 sec within an area of 900 km 2 . Synthetics calculated from the three-asperity model explain 85% of the data and represent 98% of the total variance reduction. Our results indicate that slip is conned to the shallow region of the fault, deep slip patches are less constrained, and that the slip distribution may be representative of fault segmentation along the Chelungpu fault system.
Expression and function of gingival fibroblast C1q receptors are upregulated by interleukin-1β and transforming growth factor-β

In injury and inflammation, complement (C) component C1q, in addition to its central role in initiation of classical pathway of complement activation, modulates diverse cellular functions by binding to specific cell surface receptors. Interaction of substrate-bound C1q with receptors for the collagen-like domain of C1q (C1qRC) of human gingival fibroblasts (HGF) promotes cell attachment. We investigated modulation of the adhesive function and expression of C1qRC by interleukin-1 beta (IL-1 beta) and transforming growth factor-beta (TGF-beta). Confluent fibroblast monolayers were incubated under standard culture conditions with or without cytokines. C1qRC function was measured by attachment assays. IL-1 beta and TGF-beta increased fibroblast adhesion to C1q to 146% and 131% of controls, respectively. Cytokine enhancement of HGF adhesion was concentration-dependent, saturable (20 ng/ml IL-1 beta; 1 ng/ml TGF-beta) and time-dependent (IL-1 beta 12-hr peak; TGF-beta 24-hr peak). Effect of IL-1 beta and TGF-beta on C1qRC expression was assessed by flow cytometry measurements of fluorescence intensity of cells stained with C1q and FITC anti-C1q antibody, and by binding studies with 125I-C1q. Cells treated with cytokines displayed a two- to four-fold increased fluorescence of cell-bound C1q compared to controls. Binding studies indicated the increased fluorescence correlated with increase in number of C1qRC in both IL-1 beta (4.7 x 10(6)/cell) and TGF-beta (3.9 x 10(6)/cell)-treated cells, compared to control (3.0 x 10(6)/cell), but had no effect on binding affinity. Rates of internalization of receptor-bound C1q were similar in cytokine-treated cells and controls. We propose from these data that IL-1 beta and TGF-beta have the ability to upregulate C1qRC expression, and this effect contributes to increased adhesion of HGF to substrate-bound C1q.
Cooperativity in Cellular Biochemical Processes: Noise-Enhanced Sensitivity, Fluctuating Enzyme, Bistability with Nonlinear Feedback, and Other Mechanisms for Sigmoidal Responses

Cooperativity in classical biophysics originates from molecular interactions; nonlinear feedbacks in biochemical networks regulate dynamics inside cells. Using stochastic reaction kinetic theory, we discuss cooperative transitions in cellular biochemical processes at both the macromolecular and the cellular levels. We show that fluctuation-enhanced sensitivity (stochastic focusing) shares an essential feature with the transition in a bistable system. The same theory explains zeroth-order ultrasensitivity with temporal cooperativity. Dynamic cooperativity in fluctuating enzyme (i.e., dynamic disorder), stochastic focusing, and the recently proposed stochastic binary decision all have a shared mechanism: They are generalizations of the hyperbolic response of Michaelis-Menten kinetics x/(K+x), with fluctuating K or stochastic x. Sigmoidal dependence on substrate concentration necessarily yields affinity amplification for competing ligands; both sigmoidal response and affinity amplification exhibit a square l...
Evidence for anomalous effects on the current evolution in the tokamak hybrid operating scenarios

Alternatives to the usual picture of advanced tokamak (AT) discharges are those that form when anomalous thermal conductivity and/or resistivity alter plasma current and pressure profiles to achieve stationary characteristics through self-organizing mechanisms where a measure of desired AT features is maintained without external current-profile control. Regimes exhibiting these characteristics are those where the safety factor (q) evolves to a stationary profile with the on-axis and minimum q ∼ 1. Operating scenarios with fusion performance exceeding H-mode at the same plasma current and where the inductively driven current density achieves a stationary configuration with either small or nonexisting sawteeth should enhance the performance of ITER and future burning plasma experiments. We present simulation results of anomalous current-profile formation and evolution using theory-based hyper-resistive models. These simulations are stimulated by experimental observations with which we compare and contrast the simulated evolution. We find that the hyper-resistivity is sufficiently strong to modify the current-profile evolution to achieve conditions consistent with experimental observations. Modelling these anomalous effects is important for developing a capability to scale current experiments to future burning plasmas.
Psychological, Behavioral, and Social Characteristics Associated with Early Forced Sexual Intercourse among Pregnant Adolescents

In a research study exploring patterns of substance use and sexual behavior among pregnant adolescent women under the age of 18, the data were examined for associations between a history of early forced sexual intercourse and indicators of psychological, behavioral, and social problems during adolescence. The findings indicate that many pregnant adolescent women have experienced early forced sexual intercourse and that the experience has had a measurable effect on their functioning during adolescence. Compared to reported nonvictims, reported victims were more depressed, anxious, and self-conscious, had lower self-esteem, used more crack, cocaine, and other drugs (excluding marijuana), and engaged in a higher number of delinquent activities. In addition, they moved more frequently, experienced poorer quality family relationships, and felt that they had received less emotional support from family and friends over the past year. Discriminant function analysis succeeded in distinguishing reported victims fro...
The principles, competencies, and curriculum for educating dental therapists: a report of the American Association of Public Health Dentistry Panel.

A panel of academicians was formed to develop an educational plan for dental therapists. The panel met over a 14-month period of time (2010-2011). The panel interviewed leadership from dental therapy educational programs in New Zealand, Canada, Alaska, and the University of Minnesota. The panel was structured into three subcommittees – principles, competencies, and curriculum to develop an educational plan for a 2-year postsecondary school dental therapy program. Reports from the three subcommittees are presented in this article along with introductory information and a discussion about the reports. A fourth subcommittee considered career pathways, and its report is presented as a separate article in this special issue. The final work of the panel was to consider accreditation issues regarding dental therapist programs, and its report is also presented in this issue.
The 87Sr/86Sr ratios of lacustrine carbonates and lake-level history of the Bonneville paleolake system

Lakes in the Bonneville basin have fluctuated dramatically in response to changes in rainfall, temperature, and drainage diversion during the Quaternary. We analyzed tufas and shells from shorelines of known ages in orderto develop a relation between 8 7 Sr/ 8 6 Sr ratio of carbonates and lake level, which then can be used as a basis for constraining lake level from similar analyses on carbonates in cores. Carbonates from the late Quaternary shorelines yield the following average 8 7 Sr/ 8 6 Sr ratios: 0.71173 for the Stansbury shoreline (22-20 1 4 C ka; 1350 m), 0.71153 for the Bonneville shoreline (15.5-14.5 1 4 C ka; 1550 m), 0.71175 for the Provo shoreline (14.4-14.0 1 4 C ka; 1450 m), 0.71244 for the Gilbert shoreline (∼10.3-10.9 1 4 C ka; 1300 m), and 0.71469 for the modern Great Salt Lake (1280 m). These analyses show that the 8 7 Sr/ 8 6 Sr ratio of lacustrine carbonates changes substantially at low- to mid-lake levels but is invariant at mid- to high-lake levels. Sr-isotope mixing models of Great Salt Lake and the Bonneville paleolake system were constructed to explain these variations in 8 7 Sr/ 8 6 Sr ratios with change in lake level. Our model of the Bonneville system produced a 8 7 Sr/ 8 6 Sr ratio of 0.71193, very close to the observed ratios from high-shoreline tufa and shell. The model verifies that the integration of the southern Sevier and Beaver rivers with the Bear and others rivers in the north is responsible for the lower 8 7 Sr/ 8 6 Sr ratios in Lake Bonneville compared to the modern Great Salt Lake. We also modeled the 8 7 Sr/ 8 6 Sr ratio of Lake Bonneville with the upper Bear River diverted into the Snake River basin and obtained an 8 7 Sr/ 8 6 Sr ratio of 0.71414. Coincidentally, this ratio is close to the observed ratio for Great Salt Lake of 0.71469. This means that 8 7 Sr/ 8 6 Sr ratios of >0.714 for carbonate can be produced by climatically induced low-lake conditions or by diversion of the upper Bear River out of the Bonneville basin. This model result also demonstrates that the upper Bear River had to be flowing into the Bonneville basin during highstands of other late Quaternary lake cycles: carbonates from the Little Valley (130-160 ka) and Cutler Dam (59 ′ 5 ka) lake cycles returned 8 7 Sr/ 8 6 Sr ratios of 0.71166 and 0.71207, respectively, and are too low to be produced by a lake without the upper Bear River input.
Tumor Induction by Cryptococcus neoformans

Abstract A human isolate of Cryptococcus neoformans strain CIA, which was originally obtained in 1963, produced fatal disease in mice. Postmortem examinations showed extensive central nervous system disease. After using this yeast for research for 7 years, we found that it began to produce large tumors after intraperitoneal inoculation in mice. The present study showed that the tumors consisted of large agglomerates of yeast cells, capillaries, and reticular stroma. In concomitant experiments, the same C. neoformans strain, introduced into the lungs of mice in an aerosol, produced asymptomatic infections. A definition for the term “cryptococcoma” is proposed.
A brain-targeted, modified neurosin (kallikrein-6) reduces α-synuclein accumulation in a mouse model of multiple system atrophy.

Multiple system atrophy (MSA) is a progressive, neurodegenerative disease characterized by parkinsonism, resistance to dopamine therapy, ataxia, autonomic dysfunction, and pathological accumulation of α-synuclein (α-syn) in oligodendrocytes. Neurosin (kallikrein-6) is a serine protease capable of cleaving α-syn in the CNS, and we have previously shown that lentiviral (LV) vector delivery of neurosin into the brain of a mouse model of dementia with Lewy body/ Parkinson’s disease reduces the accumulation of α-syn and improves neuronal synaptic integrity. In this study, we investigated the ability of a modified, systemically delivered neurosin to reduce the levels of α-syn in oligodendrocytes and reduce the cell-to-cell spread of α-syn to glial cells in a mouse model of MSA (MBP-α-syn). We engineered a viral vector that expresses a neurosin genetically modified for increased half-life (R80Q mutation) that also contains a brain-targeting sequence (apoB) for delivery into the CNS. Peripheral administration of the LV-neurosin-apoB to the MBP-α-syn tg model resulted in accumulation of neurosin-apoB in the CNS, reduced accumulation of α-syn in oligodendrocytes and astrocytes, improved myelin sheath formation in the corpus callosum and behavioral improvements. Thus, the modified, brain-targeted neurosin may warrant further investigation as potential therapy for MSA.
Remarks on Simon's Comments

Herbert Simon has commented on my article, to which I have been asked to respond. This sequence of events is slightly misleading: It suggests the familiar article-critique-rebuttal pattern, whereas I believe that, in fact, Simon and I are in substantial agreement about the nature of causation and its formal model. A few points of disagreement do remain, though, and my purpose in these remarks will be to underscore these points and restate my opinions regarding them. Among the issues that are not in dispute are the elegance of causal ordering, and the utility of the notion in tasks such as diagnosis. The concept is as attractive now as it was when it was first introduced in the 1950s (I first encountered it in Lerner, 1965). Also, to the extent that my brief comments on it in my article suggested that the notion of causal ordering is inherently algebraic and precludes a sentential version, I am glad that the record is now set straight. I disagree, however, that causal ordering is “isomorphic” to my nonmonotonic account of causation. I wish it were: A major attraction of causal ordering is its simplicity, which contrasts with my almost embarassingly complex technical development. In fact, as alluded to in my article, one of the reasons that technical development is preceded by an intuitive exposition is the potential for recapturing the ideas in simpler form. Isomorphism between structures is defined only relative to specified operations, and it is not clear to me which operations are relevant here. However, such mathematical considerations seem beside the point, and Simon’s position seems clear enough. I will take it to be that (a) causal ordering possesses all the desirable properties of causation possessed by the nonmonotonic account; (b) causal ordering does not introduce any undesirable properties; (c) by my own admission, causal ordering is simpler; and, therefore (d) causal ordering is, to use a phrase due to the late Alan Perlis, an improvement on its successor. In my article I list eight properties that I wish to associate with causation. Of these, Simon agrees with all but two, and expresses partial agreement
Age and gender differences in risky driving: The roles of positive affect and risk perception

A phone survey of 504 teen (age 16-20) and 409 adult (age 25-45) drivers in the US state of Alabama was conducted to examine the relationships among risk perception, positive affect and risky driving. Male drivers reported engaging in risky driving behaviors more frequently than female drivers and teen drivers reported engaging in risky driving behaviors more frequently than adult drivers. Positive affect (liking for risky driving behaviors) and perceived risk mediated the relationships of age and gender with risky driving. Affect and risk perception were independent predictors of risky driving behavior. Interactions of positive affect and perceived risk with gender and age showed that positive affect more strongly predicted risky driving for teen and male drivers than for adult and female drivers. These findings are interpreted in the context of dual process models of behavioral decision making. Future research into interventions designed to moderate the positive affect surrounding driving may have promise for reducing risky driving behavior.
CYCLIC ERUPTIVE BEHAVIOR OF SILICIC VOLCANOES

Silicic volcanism seems chaotic: the styles, magnitudes, and/or timing of successive eruptions may be without apparent pattern, or patterns may merge, fade, or abruptly change. However, geophysical monitoring of recent eruptions shows that some silicic volcanoes can exhibit cyclic eruptive behavior wherein periods of explosive activity or rapid extrusion alternate with periods of repose. The cycles are commonly observed in time-averaged amplitudes of eruption-related seismicity and also have been observed in ground-surface tilt data. When tilt and seismicity are both observed during oscillatory behavior, as at Soufriere Hills volcano on Montserrat, British West Indies, they correlate in time. Cycle periods range from hours to days, and cycle amplitudes and waveforms vary widely. Complex oscillatory behavior is also sometimes observed during high-pressure (tens of MPa) extrusion of industrial polymer melts. With this phenomenon as a guide, we construct a simple dynamic model for the oscillatory behavior of erupting volcanoes. We propose that cyclic eruptions result from Newtonian flow of compressible magma through the volcanic conduit combined with a stick-slip condition along the conduit wall, in analogy to the behavior of industrial polymers. If magma is forced into the conduit at a constant rate, pressure and flow rate rise. If the flow rate through the conduit exceeds a threshold value, the flow resistance abruptly drops as the magma slips along a shallow portion of the conduit wall. This reduces resistance to flow and causes the flow rate to jump to a higher value. If this enhanced flow rate exceeds the supply rate, both pressure and flow rate decline as the compressed magma in the conduit expands. Eventually slip ceases as the magma reattaches to the conduit wall at a flow rate less than the supply rate. Consequently pressure begins to increase, and the cycle begins again. This simple model reconciles a variety of disparate phenomena associated with cyclic silicic volcanism and provides a paradigm to interpret cyclic eruptive behavior.
Mediastinoscopic Subtotal Removal of Mediastinal Cysts

Study objective Evaluate the use of mediastinoscopy in the surgical diagnosis and treatment of mediastinal cystic masses in adults. Design Case reports and literature review. Setting Academic department of surgery. Patients Three consecutive adults with mediastinal masses identified on plain radiographs and CT. Interventions Operative mediastinoscopy. Measurements and results All patients were successfully treated with removal of cyst wall, establishment of diagnosis, and same-day hospital discharge. Conclusions Simple mediastinoscopic removal of mediastinal cysts offers the same potential for diagnosis and treatment as more conventional methods, with a potential for less morbid and more cost-effective care.
Repeated scopolamine treatment does not enhance the acth response to physostigmine in rats

Adult male rats were treated daily with scopolamine (10 mg/kg) for two weeks and the ACTH response to acute physostigmine (0.1 mg/kg) challenge was evaluated. Although physostigmine produced a significant increase in A CTH concentrations in all animals, repeated scopolamine administration did not alter basal ACTH concentrations or the ACTH response to physostigmine. The results are discussed in relation to dysregulation of the hypothalamic-pituitary adrenal (HPA) axis and rapid eye movement (REM) sleep in depression, as mediated by differential adaptive responses of central cholinergic systems. Depression 1:101–104 (1993). © 1993 Wiley-Liss, Inc.
Two-photon width of singlet positronium and quarkonium with arbitrary total angular momentum.

In this paper we derive {Gamma}{sub {gamma}{gamma}} for {ital S}=0 positronium and quarkonium states with all allowed quantum numbers ({ital J}{sup {ital P}{ital C}}=0{sup {minus}+},2{sup {minus}+},4{sup {minus}+},...), in both nonrelativistic and relativistic regimes. {gamma}{gamma} partial widths have previously been published only for fermion-antifermion states with {ital J}{sup {ital P}{ital C}}=0{sup {plus minus}+},1{sup ++} (off-shell photons), and 2{sup {plus minus}+}. The topic of higher-spin {gamma}{gamma} partial widths is of current interest in part because a recent nonrelativistic {ital q{bar q}} calculation for 2{sup {minus}+} finds a much smaller {gamma}{gamma} partial width than the {approx}1 keV observed for the {ital I}=1,{ital J}{sup {ital P}{ital C}}=2{sup {minus}+} state {pi}{sub 2}(1670). We find very large relativistic corrections to the nonrelativistic (contact) approximation for this width as well as large systematic uncertainties in the procedure used to incorporate the physical resonance mass. Our relativistic {ital q{bar q}} estimate for {Gamma}{sub {gamma}{gamma}}({pi}{sub 2}(1670)) is 0.1--0.3 keV, which is somewhat smaller than the experimental value. This discrepancy may only reflect inaccuracies in the theoretical technique. Finally, we quote relativistic numerical results for the {gamma}{gamma} widths of various 0{sup {minus}+}, 2{sup {minus}+}, and 4{sup {minus}+} ({ital u{bar u}}{minus}{ital d{bar d}})/ {radical}2 , {ital c{bar c}} and {ital b{barmore » b}} states in a Coulomb-plus-linear potential model.« less
Development of a parallel computational fluid dynamics algorithm on a hypercube computer

One of the main factors limiting the widespread use of computational fluid dynamics codes for engineering design is their very large requirements both in terms of computer memory and CPU time. Distributed memory parallel computers offer both the potential for a dramatic improvement in cost/performance over conventional supercomputers and the scalability to large numbers of processors that is required if performance beyond that of current supercomputers is to be achieved. As part of an evaluation to explore the potential of such machines for computational fluid mechanics applications, a concurrent algorithm for the solution of the Navier-Stokes equations has been developed and demonstrated on a hypercube parallel computer. The algorithm is based on a domain decomposition of a well-established serial pressure correction algorithm. The algorithm is demonstrated on both a 32-node scalar and eight-node vector Intel iPSC/2 for complicated two-dimensional laminar and turbulent flow problems with different grid sizes and numbers of processors. Speed-ups relative to a single processor of 12.9 with 16 processors and 20.2 with 32 processors are achieved on a scalar iPSC/2, demonstrating the parallel efficiency of the algorithm. Measured performance on a 32-node scalar iPSC/2 exceeds one-sixth that of a Cray X-MP running the original serial algorithm. The performance of the algorithm on an eight-node vector iPSC/2 exceeds that of the larger scalar hypercube and is about one-fifth that of the Cray X-MP. With cost/performance more than 10 times better than the Cray, these results dramatically show the cost effectiveness of vector hypercubes for this class of fluid mechanics algorithm.
Energy efficient OFDM transceiver based on traffic tracking and adaptive bandwidth adjustment

We report a solution for power savings in OFDM-based digital transceivers, by adaptively tuning signal bandwidth, sampling rate, and number of parallel processing modules based on instant network traffic load.
Toward a Social Graph Recommendation Algorithm: Do We Trust Our Friends in Movie Recommendations?

Social networks provide users with information about their friends, their activities, and their preferences. In this paper we study the effectiveness of movie recommendations computed from such communicated preferences. We present a set of social movie recommendation algorithms, which we implemented on top of the Facebook social network, and we compare their effectiveness in influencing user decisions. We also study the effect of showing users a justification for the recommendations, in the form of the profile pictures of the friends that caused the recommendation.
Mixotrophy stirs up our understanding of marine food webs.

Mixotrophy among planktonic eukaryotic organisms is broadly defined as the combined use of photosynthetic and heterotrophic nutrition within a single organism. The conventional view of species as either phototrophic (capable of producing energy and carbon for growth using only inorganic compounds and light) or heterotrophic (wholly dependent on preformed organic material for nutrition) is a preconception rooted in the fact that most terrestrial species can easily be divided into “plants” or “animals.” Indeed, the diversity of terrestrial organisms that combine photosynthetic and heterotrophic nutrition is mostly relegated to a dozen or so genera of carnivorous plants that capture and digest insects and other small creatures for the nutrients they contain, but also capture light energy via photosynthesis. In contrast to life on land, mixotrophic nutrition is widespread among single-celled and multicellular organisms comprising the ocean’s plankton. The ecological significance for the species that possess this behavior has not been lost on biologists who have endeavored to document and understand mixotrophy, but its importance to pelagic food-web structure and function has not yet become entrained into mathematical models of marine ecosystems. In PNAS, Ward and Follows (1) address this disparity, and provide one of the first attempts to incorporate mixotrophic nutrition into biogeochemical models of oceanic food webs. The authors use their model to estimate the impact that mixotrophy has on food-web structure, the efficiency of carbon transfer to higher trophic levels, and the sinking of carbon into the deep ocean.