cssi/SciSciGPT-SciSciNet huggingface dataset:
Ice ages: Evidence for past melting at the base of the GISP2 ice core from uranium-thorium disequilibria dating

Abstract In order to further develop 238U-234U-230Th disequilibria techniques for dating polar ice, we measured these nuclides by mass spectrometric methods for silty ice samples from the base of the GISP2 central Greenland ice core. We separated the samples by filtration and analyzed the 200 nm (particulate) filtered fractions. 230Th/234U activity ratios are quite low in the We have modeled these results using a two component mass balance calculation, with dissolved and particulate pools for each radionuclide. Although the model results vary slightly depending on assumptions, corrected dates for when the samples were last frozen range from 3500-8300 years ago, with typical 2σ uncertainties of 600-2300 years. These results are generally consistent with other geochemical and chronological data for Greenland ice cores and the notion of ice melting at the base of large continental ice sheets, even in areas that are currently frozen. Based on our U-series results and gas data in the literature, prior melting of the GISP2 ice core has evidently occurred for most of the 13 m thick silty basal layer but is most pronounced for the deepest 2 m. We also suggest that this new 230Th ingrowth method for dating previously melted ice may be more generally applicable to samples with a range of particulate matter concentrations.
Soliton Resolution for Equivariant Wave Maps on a Wormhole

We study finite energy $${\ell}$$ –equivariant wave maps from the (1+3)–dimensional spacetime $${\mathbb{R} \times (\mathbb{R} \times \mathbb{S}^2) \rightarrow \mathbb{S}^3}$$ where the metric on $${\mathbb{R} \times (\mathbb{R} \times \mathbb{S}^2)}$$ is given by $$ds^2 = -dt^2 + dr^2 + (r^2 + 1) \left ( d \theta^2 + \sin^2 \theta d\varphi^2 \right ), \quad t,r \in \mathbb{R}, (\theta,\varphi) \in \mathbb{S}^2.$$ The constant time slices are each given by a Riemannian manifold with two asymptotically Euclidean ends at $${r = \pm \infty}$$ that are connected by a 2–sphere at r = 0. The spacetime $${\mathbb{R} \times (\mathbb{R} \times \mathbb{S}^2)}$$ has appeared in the general relativity literature as a prototype wormhole geometry (but is not expected to exist in nature). Each $${\ell}$$ –equivariant finite energy wave map can be indexed by its topological degree n. For each $${\ell}$$ and n, there exists a unique, linearly stable energy minimizing $${\ell}$$ –equivariant harmonic map $${Q_{\ell,n} : \mathbb{R} \times \mathbb{S}^2 \rightarrow \mathbb{S}^3}$$ of degree n. In this work, we prove the soliton resolution conjecture for this model. More precisely, we show that modulo a free radiation term every $${\ell}$$ –equivariant wave map of degree n converges strongly to $${Q_{\ell,n}}$$ . This fully resolves a conjecture made by Bizon and Kahl. Previous work by the author proved this result for the corotational case $${\ell = 1}$$ and established many preliminary results that are used in the current work.
A Millimeter-Wave Dynamic Antenna Array for Classifying Objects Via Sparse Fourier Domain Sampling

We present a dynamic antenna array operating at 38 GHz for detecting strong Fourier domain (spatial frequency) features of a scene to demonstrate the potential for object classification. Sharp edges on objects manifest as broad-spectrum spatial frequency signals in the Fourier domain at angles orthogonal to the edge direction. By sampling only a sparse ring of spatial frequency information, these broad spatial frequency responses can be identified, and objects can be classified without full image reconstruction. The technique is based on active interferometric imaging, where noise signals are transmitted to mimic thermal radiation, thereby allowing the use of the Van Cittert-Zernike theorem to capture scene intensity information in the Fourier domain. Sparse spatial frequency information is captured by a dynamic 38 GHz two-element interferometric antenna array that rotates in the spatial domain to synthesize a ring filter in the spatial frequency domain. We experimentally demonstrate that edge-induced broad-spectrum responses can be identified for the classification of simple objects using this method.
Searching for Knotted Spheres in 4-dimensional Space

We search for knotted spheres in 4-dimensional space. This includes the generation of random examples, and experimental methods for the classification by topological type. Here we focus on a first step, to detect trivially knotted spheres.
Development of Reduced Order Models to Non-modeled Regions

Model reduction and model expansion techniques have been used in many structural dynamic modeling applications to map detailed FEM at the full set of DOF (NDOF) to an abbreviated set of active DOF (ADOF) while preserving the dynamic characteristics of interest. In order to perform model reduction and model expansion, the ADOF model must be a subset of the NDOF model. For complex structures with hollow spaces (i.e. wind turbine blades, airframes, hollow fuselage sections, etc.), model reduction to a “beam-like” neutral axis is not possible.
Fast orientation mapping from HARDI

This paper introduces a new, accurate and fast method for fiber orientation mapping using high angular resolution diffusion imaging (HARDI) data. The approach utilizes the Fourier relationship between the water displacement probabilities and diffusion attenuated magnetic resonance (MR) signal expressed in spherical coordinates. The Laplace series coefficients of the water displacement probabilities are evaluated at a fixed distance away from the origin. The computations take under one minute for most three-dimensional datasets. We present orientation maps computed from excised rat optic chiasm, brain and spinal cord images. The developed method will improve the reliability of tractography schemes and make it possible to correctly identify the neural connections between functionally connected regions of the nervous system.
Failure analysis in capacitors

Multilayer capacitors are made by a complex process that allows local inhomogeneities to occur. Such localized deviations from the norm are potential failure sites. Measurements of capacitance and loss tangent at fixed frequencies do not show any differences that would suggest the presence of structural variations. One measurement that does show pronounced unit-to-unit differences is the capacitance vs. frequency plot in the frequency region below and above self-resonance. Unit-to-unit variations were found when dc bias voltages were applied. In particular, secondary resonances, indicative of the presence of structural inhomogeneities were found to occur at frequencies near to the self-resonance frequency.
Kinetic, equilibrium, and thermodynamic analysis of macromolecular interactions with BIACORE.

Publisher Summary This chapter reviews that the popularity of using biosensors to characterize biomolecular interactions continues to grow. These instruments are capable of providing information about the energetics of macromolecular interactions without labeling. While commercial instruments such as BIACORE are relatively easy to use, extracting accurate rate constants for a reaction requires careful experimental technique and robust methods of data analysis. It discusses how biosensors can be used as a biophysical tool to determine equilibrium constants and kinetic rate constants for binding events. By measuring reactions at different temperatures, it is possible to extract thermodynamic information about the system. The model system used in this study involves the interaction of interleukin 2 (IL-2) ligand with the α subunit of its receptor. The chapter concludes that BIACORE is a powerful tool used to measure the reaction kinetics and equilibrium constants for biological molecules. Improved methods for data collection and processing make it possible to dramatically improve the quality of biosensor data. The ability to describe binding data with simple interaction models validates the technology as a tool for kinetic analysis. Recording the temperature dependence of reaction parameters makes it possible to extract some thermodynamic information about the binding reaction. Together, kinetic and thermodynamic data will increase the understanding of biomolecular recognition events.
Java - Beyond The Hype

It seems impossible to open a computer magazine that does not feature an article on Java. Even mainstream newspapers and magazines have had major articles on Java. Or, can you remember the last time there was a $100,000,000 venture capitol fund set up for products developed in a specific computer language? The purpose of this lecture is to try to separate current fact from fancy by explaining what Java can and cannot do, what it is good and not so good for. In the end, I should add, a great deal of the hype may be justified; it is just that it is not true yet: the last section explains some of what has been announced as part of Java 1.1. It is the features in this version that will, when implemented make much of the hype justified.
Abstract 3921: Generation of a T-cell lymphoma mouse model based on chronic LPS challenge and TGF-β signaling disruption

Background: It has been demonstrated that elevated alcohol intake affects the permeability of the gut allowing endotoxins such as LPS to enter into the portal circulation and to promote liver ethanol toxicity. It has also been shown that increased ethanol intake and LPS challenge impairs liver function and affects liver tumor formation. Hence, with the aim of generating a mouse model of alcoholic liver disease that would rapidly develop steatosis, inflammation and fibrosis, we formulated a regimen that combined chronic injections of low dose LPS with ethanol feeding to mice with impaired TGF-β signaling through constitutive disruption of β2-spectrin (Sptbn1+/-) , Smad3 (Smad3+/-) or both. Methods: Wild type, Sptbn1+/-, Smad3+/- and Sptbn1+/-;Smad3+/- female mice between 8-10 weeks of age were fed orally with a Lieber-DeCarli-based diet containing 6.7% ethanol, and 2-4 weeks later they were injected with 2mg/kg LPS via i.p. 3 times/week for up to 20 weeks or death, whichever occurred first. Survival analysis was done using the Gehan-Breslow-Wilcoxon test. Results: Unexpectedly, the mice treated with chronic low dose LPS and fed the alcohol-containing diet only developed a mild liver phenotype, i.e. steatosis but not hepatitis or fibrosis. Instead, these mice developed very aggressive T-cell lymphomas with massive abdominal and thoracic hemorrhages to which the TGF-β mutant mice succumbed more rapidly than the wild type mice. The median survival of the mutants oscillated between 39 to 42 weeks vs. undefined of the wild type mice. We found statistically significant decreased survival of the mutant mice vs. the wild type (p-values between 0.0015 and 0.028). Conclusions: To our knowledge, this is the first report of a mouse model of aggressive T-cell lymphoma based on chronic challenge with low dose LPS and alcohol feeding. We are currently assessing the cross-talk of the LPS/TLR4 and TGF-β pathways in T-cells from these mice to understand the molecular mechanism underlying the accelerated rate of lymphoma development in these mice. Citation Format: Nina M. Munoz, Lior H. Katz, Mihai I. Gagea, Asif Rashid, Lopa Mishra. Generation of a T-cell lymphoma mouse model based on chronic LPS challenge and TGF-β signaling disruption. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3921. doi:10.1158/1538-7445.AM2014-3921
Coordinate formalism on Hilbert manifolds

Infinite-dimensional manifolds modelled on arbitrary Hilbert spaces of functions are considered. It is shown that changes in model rather than changes of charts within the same model make coordinate formalisms on finite and infinite-dimensional manifolds deeply similar. In this context the infinite-dimensional counterparts of simple notions such as basis, dual basis, orthogonal basis, etc. are shown to be closely related to the choice of a model. It is also shown that in this formalism a single tensor equation on an infinite-dimensional manifold produces a family of functional equations on different spaces of functions.
Correlation between in Vivo Toxicity and Preclinical in Vitro Parameters for the Immunotoxin Anti-B4-blocked Ricin

Anti-B4-blocked ricin (Anti-B4-bR) is an immunotoxin comprised of the anti-B4 monoclonal antibody and the protein toxin, "blocked ricin." In blocked ricin, the galactose-binding sites of the ricin B-chain which mediate nonspecific binding to cells are blocked by covalently linked affinity ligands prepared from N-linked oligosaccharides of fetuin. Blocked ricin consists of two species, one with two covalently attached ligands and one with three covalently attached ligands. In a Phase I dose escalation clinical trial, Anti-B4-bR was administered to patients with relapsed and refractory B-cell neoplasms by 7-day continuous infusion. Although several different lots of Anti-B4-bR had similar IC37 values as determined by in vitro cytotoxicity testing on cultured human cell lines, these lots differed in their in vivo toxicity when administered to patients. Thus, IC37 values alone were not sufficient to predict in vivo toxicity. We report that the degree of cell kill at concentrations of drug that saturate the B4 antigen and murine 50% lethal dose values provide additional parameters that may be predictive of in vivo cytotoxicity. Furthermore, we performed detailed cytotoxicity studies of the ricin species containing two and three covalently attached ligands, respectively. In vitro cytotoxicity testing using these samples revealed that Anti-B4-bR made with blocked ricin containing two covalently attached ligands is capable of depleting five logs of target cells in an in vitro cytotoxicity assay, while Anti-B4-bR comprised of blocked ricin with three ligands can deplete only one log of cells. Log cell kill at antigen saturating concentration, murine 50% lethal dose and biochemical analysis of the composition of blocked ricin are therefore important considerations for establishing the potential efficacy and safety of Anti-B4-bR.
Presence and Television: The Role of Screen Size.

Film and a number of emerging entertainment technologies offer media consumers an illusion of nonmediation known as presence. To investigate the possibility that television can evoke presence, 65 undergraduate students were shown brief examples of rapid point-of-view movement from commercially available videotapes on a television with either a small screen (12 inches [30.5 cm], measured diagonally) or a large screen (46 inches [116.8 cm]). Participants' responses were measured via a questionnaire and a computer-based recording of arousal (electrodermal activity). Viewers of both televisions reported an enjoyable sense of physical movement, excitement, involvement, and a sense of participation. Furthermore, as predicted, participants who watched the large screen television thought the movement in the scenes was faster, experienced a greater sense of physical movement, enjoyed the movement to a greater extent, found the viewing experience more exciting, and were more physiologically aroused. Practical and theoretical implications are discussed.
Reinventing the University Through the Teaching of Diversity

University reform encompasses an increased emphasis on the social and emotional development of students. In particular, the development of caring, empathy, and community are emphasized. This team of psychology professors approaches the task of university reform by presenting both its philosophy of diversity inclusion and specific inclusion strategies as means of promoting enhanced development of our students. Although the discipline of psychology is used as an example, the philosophical argument and the strategic approaches may be applied to other disciplines.
Penalty and Barrier Methods

Penalty and barrier methods are procedures for approximating constrained optimization problems by unconstrained problems. The approximation is accomplished in the case of penalty methods by adding to the objective function a term that prescribes a high cost for violation of the constraints, and in the case of barrier methods by adding a term that favors points interior to the feasible region over those near the boundary. Associated with these methods is a parameter c or μ that determines the severity of the penalty or barrier and consequently the degree to which the unconstrained problem approximates the original constrained problem. For a problem with n variables and m constraints, penalty and barrier methods work directly in the n-dimensional space of variables, as compared to primal methods that work in (n − m)-dimensional space.
LtRules: an automated software library usage rule extraction tool

The need to manually specify temporal properties of software systems is a major barrier to wider adoption of software model checking, because the specification of software temporal properties is a difficult, time-consuming, and error-prone process. To address this problem, we propose to automatically extract software library usage rules, which are one type of temporal specifications. Our approach uses a model checker to check a set of software library usage rule candidates against known good programs using that library, and identifies valid rules based on model checking results. These valid rules can help programmers learn about common software library usage. They can also be used to check new programs using the same library. We have implemented our approach in an Eclipse plug-in named LtRules, which can extract software library usage rules from C programs using BLAST as the underlying model checker.
Changes in Sociometric Choices Following Forced Integration of an Elementary School

Sociometric questionnaires were administered to all pupils in the fourth, fifth, and sixth grades in an elementary school in February 1970 (soon after forced integration had occurred), again in June 1970, and again to fifth and sixth grade pupils in February 1971. Both blacks and whites at all three grade levels chose significantly more members of their own race than members of the other race; blacks rejected whites significantly less than would be expected by chance, an effect which increased over time for older pupils; and, initially, whites rejected blacks less frequently than expected by chance, but shifted to approximately chance rejection of blacks. In January and February 1971, two observers counted interactions among pupils in each grade for ten minutes once per week for a period of five weeks. As expected, interactions increased significantly with grade level; however, subsequent analysis revealed that the primary variable determining interracial interactions is the proportion of blacks to whites in the classroom. A relatively low proportion of minority members (black or white) appears to be most effective in improving interracial relations.
The effect of the utricle on fluid flow in the semicircular canals.

The fluid mechanics of the semicircular canals is examined theoretically. This analysis confirms earlier studies that indicate that the semicircular canal can be modeled as a heavily damped, second-order system. Included for the first time, however, is an accurate accounting of the effect of the utricle on fluid flow in the canals. Using available physiological data, quantitative predictions of canal response to angular acceleration are made.
Fetal Sheep Development on Ultrasound and Magnetic Resonance Imaging: A Standard for the in utero Assessment of Models of Congenital Abnormalities

Objective: To establish normative data for the size, conspicuity, and imaging characteristics of normal developing fetal sheep organs on ultrasound (US) and magnetic resonance (MR)
Testing the metals hypothesis in Spokane, Washington.

A >7-year, time-series, epidemiologic study is ongoing in Spokane, Washington, to examine the associations between ambient particulate constituents or sources and health outcomes such as emergency ...
Optically polarized 129Xe NMR investigation of carbon nanotubes

We demonstrate the utility of optically polarized {sup 129}Xe NMR in a convection cell for measuring the surface properties of materials. In particular, we show adsorption of xenon gas on oxidatively purified single- and multiwalled carbon nanotubes. The interaction between xenon and multiwalled nanotubes produced by chemical vapor deposition was stronger than that of single- or multiwalled nanotubes produced by carbon arc discharge. Xenon was observed in gas, liquid, and adsorbed phases. The large polarization and moderate pressures of xenon ({approx}0.2 MPa) allowed resolution of multiple lines in both the gas and condensed phases of xenon in contact with carbon nanotubes. Xe gas exchanges with physisorbed xenon in two different environments. Xe adsorbs preferentially on defects, but if the number of defects is not sufficient, it will also adsorb on surface and interstitial sites. Penetration of Xe in the tube interior was not observed.
New insight into the molecular mechanisms of two-partner secretion

Two-partner secretion (TPS) systems, which export large proteins to the surface and/or extracellular milieu of Gram-negative bacteria, are members of a large superfamily of protein translocation systems that are widely distributed in animals, plants and fungi, in addition to nearly all groups of Gram-negative bacteria. Recent intense research on TPS systems has provided new insight into the structure and topology of the outer membrane translocator proteins and the large exoproteins that they secrete, the interactions between them, and mechanisms for retention of some of the secreted proteins on the bacterial surface. Evidence for secretion-dependent folding of mature exoproteins has also been obtained. Together, these findings provide a deeper understanding of the molecular mechanisms underlying these simple but elegant secretion systems.
Endothermic ion molecule reactions: II. Reactions between peptides with and without basic residues and ammonia

Endothermic ion molecule reactions: II. reactions between peptides with and without basic residues and ammonia
Modulation of eicosanoid production and cell-mediated cytotoxicity by dietary α-linolenic acid in BALB/c mice

The effects of dietary α-linolenic acid (18∶3n−3) on fatty acid composition, eicosanoid production, and cell-mediated cytotoxic activity of immune cells before and after challenge with virus or poly I-C from BALB/c mice were studied. Weanling BALB/c mice were fed purified diets containing either 10%-by-weight corn oil or linseed oil providing a ratio of 18∶3n−3 to 18∶2n−6 of 1/32 or 2/1, respectively, for 6–10 weeks. Fatty acid analysis of splenocyte phospholipids showed an appreciable increase in the percentage of n−3, and a decrease in n−6, fatty acids in splenocytes from mice fed the linseed oil diet. Splenocyte prostaglandin E and peritoneal exudate cell leukotriene C production was significantly lower in the linseed oilfed mice. In general, cell-mediated cytotoxic activity was similar for immune cells from linseed oil and corn oil-fed mice. However, 6 days after the viral challenge, splenocyte cell-mediated cytotoxic activity was significantly higher in linseed oil mice. This higher activity was associated with nonspecific cytotoxicity rather than that of viral-specific cytotoxic T-lymphocytes. Cell yields from the spleen and peritoneum were frequently significantly higher in linseed oil mice. Interactions between dietary 18∶3n−3, eicosanoid production, and immune cell proliferation and/or migration are discussed. In summary, feeding mice a diet rich in 18∶3n−3 elevates immune cell n−3 fatty acid content, reduces eicosanoid synthesis and, to a limited extent, enhances the cell-mediated cytotoxic response to a viral challenge.
Genital Herpes The Need for Counseling

Genital herpes victim face a -myriad of physical, phychological, and emotional problems affecting not only their health, but their sexuality and sexual relationships as well. Due to changing mores and the epidemic proportions of this disease, nurses will be seeing increasing numbers of genital herpes patients. Presented below is information to help nurses offer these patients sound factual information, counseling, and appropriate referrals.
Effects of invasive scotch broom on soil properties in a Pacific coastal prairie soil

Scotch broom (Cytisus scoparius) is a leguminous shrub, native to Europe that has invaded significant areas of the Pacific Northwest and rigorously competes with native vegetation. Mineral soils under scotch broom colonies and adjacent coastal prairie on the Mendocino Coast of Northern California were sampled to determine how soil properties and microbial processes have been affected. Soils under scotch broom were significantly more acidic and had greater organic matter content than prairie soils. The activities of two soil enzymes responsible for processing major detrital carbon and phosphorus pools were significantly higher under scotch broom. Organic matter accumulation with no change in C:N, a greater increase in phosphatase activity (123%) than in β-glucosidase (84%) under scotch broom, and a significant difference between soil C:P under scotch broom (619) and prairie vegetation (470) all suggest that the coupling of nutrient cycles has changed.
The effect of aerodynamic and structural detuning on turbomachine supersonic unstalled torsional flutter

The effects of alternate-blade structural detuning and adjacent-blade alternate-circumferential-spacing aerodynamic detuning on the supersonic unstalled torsional flutter stability of a turbomachine rotor are investigated analytically. An unsteady aerodynamic model employing influence coefficients is constructed for the case of a flat-plate-airfoil cascade in torsion-mode harmonic oscillation in a supersonic inviscid isentropic adiabatic irrotational perfect-gas inlet flow with a subsonic leading-edge locus. The influence coefficients and equations of motion are derived; the model is verified by applying it to the 12-blade cascade-B flow geometry studied by Verdon and McCune (1975); and the results are presented graphically. It is found that the rotor can be stabilized over the entire reduced frequency range by applying a combination of structural and aerodynamic detuning as the passive flutter-control mechanism.
Morphological control of particles

Abstract The objective of this review is to highlight the theoretical and practical aspects of particle morphological control. Materials with directional properties are opening new horizons in material science. Structural, optical, and electrical properties can be greatly augmented by the fabrication of composite materials with anisotropic microstructures or with anisotropic particles uniformly dispersed in an isotropic matrix. Examples include structural composites, magnetic and optical recording media, photographic film, and certain metal and ceramic alloys. The new applications and the need for model particles in scientific investigations are rapidly outdistancing the ability to synthesize anisotropic particles with specific chemistries and narrowly distributed physical characteristics (e.g. size distribution, shape, and aspect ratio). Anisotropic particles of many compositions have been produced but only a few (γ-Fe2O3 and AgI) are produced with any degree of chemical and physical control. These two examples are the result of literally decades of study. Unfortunately, the science and technology (mainly the technology) that have evolved are maintained as proprietary information. Thus, while we generally know what systems yield single crystal, anisotropic-shaped particles, we do not know how to make powders of these crystals with the desired control of shape uniformity, aspect ratio and phase composition. Particle shape control is a complex process requiring a fundamental understanding of the interactions between solid state chemistry, interfacial reactions and kinetics, and solution (or vapor) chemistry. During synthesis of other than a large single crystal the parameters controlling crystal growth must be balanced with the requirements for anisotropic powder nucleation and growth. Although there has been considerable progress in large single crystal growth and the synthesis of powders composed of monodispersed, spherical particles, these efforts have not often been transferred to the synthesis of anisotropic particles.
Fatigue and Overloading Behavior of Steel–Concrete Composite Flexural Members Strengthened with High Modulus CFRP Materials

Due to corrosion and the continuous demand to increase traffic loads, there is a need for an effective system which can be used to repair and/or strengthen steel bridges and structures. This paper describes an experimental program, recently completed, to investigate the fundamental behavior of steel–concrete composite scaled bridge beams strengthened with new high modulus carbon fiber-reinforced polymer (HM CFRP) materials. The behavior of the beams under overloading conditions and fatigue loading conditions was studied as well as the possible presence of shear lag at the interface of the steel surface and the CFRP strengthening material. The test results are compared to an analytical model based on the fundamental principles of equilibrium and compatibility, to predict the behavior of the strengthened steel–concrete composite beams. Based on the findings of this research work, combined with other work in the literature, a design guideline is proposed for the use of HM CFRP for strengthening the steel fle...
Observations on the morphology of Trematocarpus dichotomus Kützing and the status of the genus Dicurella1

Abstract The morphology of Trematocarpus dichotomus Kutzing was studied and carpogonial filaments observed for the first time in this genus. A comparison of Trematocarpus Kutzing and Dicurella J. Agrardh indicates close parallels in reproductive morphology and a range of vegetative structure compatible within a genus. The species of Dicurella, which DeToni (1900) had transferred to Trematocarpus but which were separated out again by Kylin (1932), are therefore reinstated in Trematocarpus.
ARRIVAL TIMES OF AIR SHOWER PARTICLES AT LARGE DISTANCES FROM THE AXIS

A study has been made of the relative times of arrival of shower particles at large distances (200 to 1500 m) from the shower axis. Data were obtained at the MIT Volcano Ranch Station, using an array of 20 scintillation detectors, one of which was shielded part of the time. The shower size, direction, and core location were determined for each event. We describe the spatial distribution of shower particles at a given instant by means of three curved surfaces: the median surface for the penetrating particles (muons), the median surface for the electrons, and the extreme front. We find that the average median surface for the muons is approximately spherical, the center being located at an atmospheric depth of 320\ifmmode\pm\else\textpm\fi{}70 g ${\mathrm{cm}}^{\ensuremath{-}2}$, and that the average median surface for the electrons has a radius of curvature of about 1 km at a distance from the axis of 450 m. The electron radius of curvature increases at greater distances. Assuming that the extreme front is spherical, its average center must be located above 320 g ${\mathrm{cm}}^{\ensuremath{-}2}$. We measured the radius for curvature of the extreme front for a small number of individual showers, but were not able to improve upon that limit.
Olfactory-evoked potentials: assessment of young and elderly, and comparison to psychophysical threshold

Olfactory-evoked potentials (OEPs) were recorded monopolarly at the Fz, Cz and Pz electrode sites in young adults and elderly subjects with an amyl acetate stimulus presented olfactometrically. Psychophysical odor thresholds for amyl acetate were determined using a two-alternative, forced-choice detection procedure. These demonstrated a decreased odor detection sensitivity in the elderly relative to tye young subjects. In accordance with the threshold findings, elderly subjects produced significantly smaller N1 and P2 amplitudes, and a trend towards longer latencies than younger subjects. Moreover, odor threshold was found to correlate with amplitude magnitude. The OEP findings, which are discussed in the context of previous OEP studies, offer promise as an objective, non-invasive measure of sensory function in both clinical and non-clinical settings.
Essential Internal Promoter in the spoIIIA Locus of Bacillus subtilis

The Bacillus subtilis spoIIIA locus encodes eight proteins, SpoIIIAA to SpoIIIAH, which are expressed in the mother cell during endospore formation and which are essential for the activation of σG in the forespore. Complementation studies indicated that this locus may be transcribed from two promoters, one promoter upstream from the first gene and possibly a second unidentified promoter within the locus. Fragments of the spoIIIA locus were expressed at an ectopic site to complement the sporulation-defective phenotype of a spoIIIAH deletion, and we determined that complementation required a fragment of DNA that extended into spoIIIAF. To confirm that there was a promoter located in spoIIIAF, we constructed transcriptional fusions to lacZ and found strong sporulation-induced promoter activity. Primer extension assays were used to determine the transcription start site, and point mutations introduced into the −10 and −35 regions of the promoter reduced its activity. This promoter is transcribed by σE-RNA polymerase and is repressed by SpoIIID. Therefore, we concluded that the spoIIIA locus is transcribed from two promoters, one at the start of the locus (P1spoIIIA) and the other within the locus (P2spoIIIA). Based on Campbell integrations and reverse transcription-PCR analysis of the P2spoIIIA region, we determined that P2spoIIIA is sufficient for transcription of spoIIIAG and spoIIIAH. Inactivation of P2spoIIIA blocked spore formation, indicating that P2spoIIIA is essential for expression of spoIIIAG and spoIIIAH. The P2spoIIIA activity is twice the P1spoIIIA activity; therefore, larger amounts of SpoIIIAG and SpoIIIAH than of proteins encoded at the upstream end of the locus may be required.
The effects of sterol biosynthesis inhibitors on cleavage in Allomyces macrogynus.

Two triazoles, cyproconazole and propiconazole, and the imidazole, prochloraz, all commercially available fungicides that inhibit 14a-demethylation during sterol synthesis, were applied to a cholesterolproducing fungus, Allomyces macrogynus, during growth phase. Concentrations of the above inhibitors 1/100-1/500 of the EC50 concentrations needed for inhibition of vegetative growth, caused failure of sporangia to cleave normally and produce uniformly sized, uniflagellate zoospores. Instead, dependent upon the concentration of fungicide used, motile cells were uniflagellate, biflagellate, triflagellate or multiflagellate with the number of nuclei corresponding to the number of flagella. The fungicides were only effective if they were present during the growth phase and impairment of cleavage could not be overcome by adding cholesterol to the discharge medium. Observations were based on light and electron microscope observations. Multinucleate cells with more than one flagellum germinated to produce normal thalli when plated on agar lacking the fungicides. The basis of the interference with cleavage is discussed.
CuInSe2 thin-film deposition on flexible plastic substrate: electrolyte recirculation rate and deposition potential effects

Copper indium diselenide (CuInSe2; CIS) layer was electrolytically plated from an aqueous medium at room temperature onto electroless nickel deposited on flexible plastic (Kapton). The CIS depositions were carried out under constant deposition potentials (−0.5 to −1.1 V vs. Ag/AgCl) and at various electrolyte flow rates (0.3 to 1.5 ml/s) under constant applied current. The resulting thin films were characterized using atomic force microscopy, energy-dispersive X-ray spectroscopy, environmental scanning electron microscopy, and X-ray diffraction. The surface morphology and the atomic composition of the deposited CIS film were found to be influenced by the deposition potential under potential control and the electrolyte recirculation rate under current control. Low electrolyte flow rates under constant current control and high cathodic deposition potential under voltage control favor the deposition of indium. CIS films of uniform deposit, smoother surfaces, and with better adhesion properties are favored by moderate electrolyte recirculation rate. At a current density of 0.6 mA/cm2, the electrolyte recirculation rate required to achieve ideal CIS atomic composition was found to be 1.0 ml/s in such a setting. The crystallinity of the film improved after annealing for 2 h at 390 °C under argon atmosphere.
Advancing a Neurodevelopmental Origin for Schizophrenia

A long-standing view has been that the study of the schizophrenic brain was the graveyard of neuropathologists. 1 Not too many years ago, inconsistencies in postmortem reports of cellular neuropathology in schizophrenics led some to conclude that such efforts were premature. Both views have since been displaced by an avalanche of consistent structural and functional evidence of microscopic pathology in the frontal and temporal lobes of schizophrenics. 2-11 Moreover, the morphologic validation of schizophrenic neuropathology has accelerated in the past decade with noninvasive methods to assess brain structure and function, establishing enlarged ventricles, reduced cortical gray matter, and hypometabolism of the frontal lobes and elements of the basal ganglia. Numerous examples have recently appeared in the ARCHIVES. 12-19 The wealth of evidence attesting to a substantial neuropathology in schizophrenia leaves few doubters. Rather, the focus has turned to the issue of which changes are reproducible signs of the pathology and
Spectral reflectance characteristics of California subalpine marsh plant communities

Reflectance spectra (414–948 nm) were recorded at ground level from leaves and canopies of subalpine marsh macrophytes near Lake Tahoe, California in 1994. Canopy architecture of the dominant species suggested that canopy reflectance should differ from one another: yellow pond-lily (Nuphar polysepalum) has a horizontal canopy; hardstem bulrush (Scipus acutus) has a vertical canopy; beaked sedge (Carex rostrata) has a spherical (randomly distributed) canopy. Data were used to 1) analyze effects of canopy architecture on reflectance properties, 2) examine effects of canopy architecture on use of spectral vegetation indices as predictors of biomass, and 3) develop methods for detecting species distributions. Leaf reflectance spectra were different in shape and magnitude across the spectrum, with canopy architecture and cover having marked effects on albedo and wavelength-dependent variance among samples.Nuphar polysepalum (horizontal canopy) showed the least difference between canopy and leaf reflectance,S. acutus (vertical canopy) reflectance was most affected by canopy architecture, andC. rostrata (spherical canopy) was intermediate. Reflectance in the near infrared (NIR) region was strongly reduced, while reflectance in the visible region was minimally affected, producing small red/NIR differences and low vegetation indices. Seven vegetation indices were tested for correlation with plant biomass. Fresh and dry green biomass ofC. rostrata were significantly correlated with all indices (p 0.13) orS. acutus (p>0.21), suggesting that spectral indices as estimators of biomass assume a spherical vegetation canopy. Differences between Thematic Mapper (TM) bands 3 (red) and 2 (green) normalized by the sum of reflectance (TM3 — TM2)/(TM3+TM2)), was significantly different among species (p<0.05) and was used as the basis of a supervised classification of a large Lake Tahoe marsh. The classification agrees with the data on distributions of species and expected distributions in relation to water depth.
A module as a torsion-free cover

LetR be a ring, and let (ℐ, ℱ) be an hereditary torsion theory of leftR-modules. An epimorphism ψ:M→X is called a torsion-free cover ofX if (1)M∈ ℱ, (2) every homomorphism from a torsion-free module intoX can be factored throughM, and (3) ker ψ contains no nonzero ℐ -closed submodules ofM. Conditions onM andN are studied to determine when the natural mapsM→M/N andQ(M)→Q(M)/N are torsion-free covers, whenQ(M) is the localization ofM with respect to (ℐ, ℱ). IfM→M/N is a torsion-free cover andM is projective, thenN⊆radM. Consequently, the concepts of projective cover and torsion-free cover coincide in some interesting cases.
Observations on Terrestrial Feeding Behavior and Growth in Diamondback Terrapin (Malaclemys) and Snapping Turtle (Chelydra) Hatchlings

ABSTRACT Food acquisition, feeding, and growth in moist terrestrial laboratory conditions were compared in 2 species of turtles that inhabit brackish water environments. Malaclemys hatchlings showed normal growth, but Chelydra hatchlings became severely stressed. The results suggest that the extended use of terrestrial habitats as a means of osmoregulation in high salinity habitats is a viable adaptive strategy for diamondback terrapin but not for snapping turtle hatchlings.
Activation of cAMP-guanine exchange factor confers PKA-independent protection from hepatocyte apoptosis

cAMP has previously been shown to promote cell survival in a variety of cell types, but the downstream signaling pathway(s) of this antiapoptotic effect is unclear. Thus the role of cAMP signaling ...
Real-Time CARS Imaging Reveals a Calpain-Dependent Pathway for Paranodal Myelin Retraction during High-Frequency Stimulation

High-frequency electrical stimulation is becoming a promising therapy for neurological disorders, however the response of the central nervous system to stimulation remains poorly understood. The current work investigates the response of myelin to electrical stimulation by laser-scanning coherent anti-Stokes Raman scattering (CARS) imaging of myelin in live spinal tissues in real time. Paranodal myelin retraction at the nodes of Ranvier was observed during 200 Hz electrical stimulation. Retraction was seen to begin minutes after the onset of stimulation and continue for up to 10 min after stimulation was ceased, but was found to reverse after a 2 h recovery period. The myelin retraction resulted in exposure of Kv 1.2 potassium channels visualized by immunofluorescence. Accordingly, treating the stimulated tissue with a potassium channel blocker, 4-aminopyridine, led to the appearance of a shoulder peak in the compound action potential curve. Label-free CARS imaging of myelin coupled with multiphoton fluorescence imaging of immuno-labeled proteins at the nodes of Ranvier revealed that high-frequency stimulation induced paranodal myelin retraction via pathologic calcium influx into axons, calpain activation, and cytoskeleton degradation through spectrin break-down.
The pseudomorphic conversion of platelets of Cr2O3 into CrN and Cr3C2

Abstract The conversion of Cr2O3 platelets into platelets of CrN and Cr3C2 by treatment with NH3 and CH4, respectively, has been demonstrated. Because the morphology of the products remained the same as that of the starting material despite significant changes in composition and crystalline structure, the reactions are considered to be pseudomorphic. The microstructures of the CrN and Cr3C2 platelets have been examined by transmission electron microscopy.
Specific ion-dependent attraction and phase behavior of polymer-coated colloids.

This paper presents results demonstrating the role of temperature and specific ions in mediating attraction between polymer-coated colloids and determining their equilibrium phase behavior. In particular, theoretical predictions of continuum van der Waals attraction between poly(ethylene oxide)−poly(propylene oxide)−poly(ethylene oxide) (PEO−PPO−PEO)-coated polystyrene colloids are used to explain measured temperature and specific ion-dependent fluid−gel transitions in dispersions of these particles. Building on previous studies of PEO−PPO−PEO-coated polystyrene colloids dispersed in aqueous NaCl media, this work reports rheologically measured fluid−gel transitions as a function of temperature and NaCl/MgSO4 composition. Adhesive-sphere predictions of percolation thresholds are fit to measured fluid−gel data by allowing the adsorbed copolymer layer thickness as a single adjustable parameter. This allows the attraction between the PEO−PPO−PEO layers to be interpreted as a function of temperature and NaCl/M...
Normal‐mode vibrational frequencies and thermodynamic properties of uracil and 4‐hydroxyuracil

Normal-mode vibrational frequencies were obtained for uracil and 4-hydroxyuracil with the MINDO/3 SCF method. MINDO/3 vibrational frequencies and the moments of inertia for STO-3G optimized geometries yielded a ΔS for U ⇄ U* of 1.06 e.u./mol by standard statistical thermodynamic equations. ΔG is then 6.29 kcal/mol in the gas phase for U ⇄ U*. The reaction field continuum model of solvent effect lowers ΔG to 5.3 kcal/mol in aqueous solution. The tautomeric equilibrium constant in solution is then 1.3 × 10−4, in good agreement with experimental values.
Effect of Aloe vera whole leaf extract on short chain fatty acids production by Bacteroides fragilis, Bifidobacterium infantis and Eubacterium limosum

Aims: To investigate the effect of Aloe vera whole leaf extract on pure and mixed human gut bacterial cultures by assessing the bacterial growth and changes in the production of short chain fatty acids. Methods and Results: Bacteroides fragilis, Bifidobacterium infantis, and Eubacterium limosum were incubated with Aloe vera extracts [0%, 0·5%, 1%, 1·5% and 2%; (w/v)] for 24 and 48 h. Short chain fatty acids production was measured by gas chromatography/mass spectrometry analyses. A significant linear increase in growth response to Aloe vera supplementation was observed at 24 h for each of the bacterial cultures; however, only B. infantis and a mixed bacterial culture showed a significant positive linear dose response in growth at 48 h. In pure bacteria cultures, a significantly enhanced dose response to Aloe vera supplementation was observed in the production of acetic acid by B. infantis at 24 h and of butyric acid by E. limosum at 24 and 48 h. In the mixed bacterial culture, the production of propionic acid was reduced significantly at 24 and 48 h in a dose-dependent fashion, whereas butyric acid production showed a significant linear increase. Conclusions: The results indicated that Aloe vera possessed bacteriogenic activity in vitro and altered the production of acetic, butyric and propionic acids by micro-organisms selected for the study. Significance and Impact of the Study: The results of the study suggest that consumption of a dietary supplement, Aloe vera, may alter the production of short chain fatty acids by human intestinal microflora.
Little Newton: an educational physics game

Little Newton is a 3D defense game in which the player learns about basic physics concepts by controlling physical attributes of projectiles. The mechanics of the game require the player to learn the basics of parabolic arcs, and friction in order to make use of the projectiles. Educational and learning theories are applied to the design in order to increase the ability of the player to learn how to play the game itself and therefore learn physics concepts in the process, balancing entertainment and educational content.