cssi/SciSciGPT-SciSciNet huggingface dataset:
Ethanol, Corn, and Soybean Price Relations in a Volatile Vehicle-Fuels Market

The rapid upward shift in ethanol demand has raised concerns about ethanol’s impact on the price level and volatility of agricultural commodities. The popular press attributes much of this volatility in commodity prices to a price bubble in ethanol fuel and recent deflation. Market economics predicts not only a softening of demand to high commodity prices but also a positive supply response. This volatility in ethanol and commodity prices are investigated using cointegration, vector error corrections (VECM), and multivariate generalized autoregressive conditional heteroskedascity (MGARCH) models. In terms of derived demand theory, results support ethanol and oil demands as derived demands from vehicle-fuel production. Gasoline prices directly influence the prices of ethanol and oil. However, of greater significance for the fuel versus food security issue, results support the effect of agricultural commodity prices as market signals which restore commodity markets to their equilibriums after a demand or supply event (shock). Such shocks may in the short-run increase agricultural commodity prices, but decentralized freely operating markets will mitigate the persistence of these shocks. Results indicate in recent years there are no long-run relations among fuel (ethanol, oil and gasoline) prices and agricultural commodity (corn and soybean) prices.
FREE VIBRATION OF CENTRIFUGALLY STIFFENED UNIFORM AND TAPERED BEAMS USING THE DYNAMIC STIFFNESS METHOD

Abstract Starting from the governing differential equations of motion in free vibration, the dynamic stiffness matrix of a uniform rotating Bernoulli–Euler beam is derived using the Frobenius method of solution in power series. The derivation includes the presence of an axial force at the outboard end of the beam in addition to the existence of the usual centrifugal force arising from the rotational motion. This makes the general assembly of dynamic stiffness matrices of several elements possible so that a non-uniform (or tapered) rotating beam can be analyzed for its free-vibration characteristics by idealizing it as an assemblage of many uniform rotating beams. The application of the derived dynamic stiffness matrix is demonstrated by investigating the free-vibration characteristics of uniform and non-uniform (tapered) rotating beams with particular reference to the Wittrick–Williams algorithm. The results from the present theory are compared with published results. It is shown that the proposed dynamic stiffness method offers an accurate and effective method of free-vibration analysis of rotating beams.
Mechanism of Hydration of Calcium Oxide

THE mechanism of hydration of calcium oxide to form calcium hydroxide has not been satisfactorily established, despite extensive investigation by many workers1–6 utilizing techniques of X-ray diffraction, sorption, radioactive tracers and electron microscopy.
National Trends in Parathyroid Surgery From 1998 to 2008: A Decade of Change

Background The introduction of limited explorations (LE) for parathyroidectomy broadened the management possibilities for hyperparathyroidism. We sought to document this evolution of change in parathyroid surgery. Study Design Members of the American Association of Endocrine Surgeons and the American College of Surgeons were sent a 49-question survey, and 256 surgeons, accounting for 46% of parathyroid operations nationwide, responded. Associations derived from questionnaire data were tested for significance using chi-square and Kruskal-Wallis methods. Results Currently, 10% of surgeons practice bilateral neck exploration, 68% practice LE, and 22% have a mixed practice. Five years ago, these percentages were, respectively, 26%, 43%, and 31%; and 10 years ago they were 74%, 11%, and 15%. Shift to LE was greatest among endocrine surgeons, high-volume surgeons, and surgeons trained by mentors who practiced LE. A focal, single-gland examination under general anesthesia and 23-hour observation are preferred by most surgeons. Half of all general surgeons, in contrast to fewer than 10% of endocrine surgeons, never monitor parathyroid hormone intraoperatively, even with LE. Dramatic differences were apparent among subsets of surgeons in operative volumes, indications for bilateral neck exploration, followup care, expertise with ultrasound and sestamibi, and perceptions of cure and complication rates. Evidence-based literature and guidance from surgical societies had the greatest influence on the decision to practice LE. Conclusions This survey formally documents the evolution of practice patterns in parathyroid surgery over the last decade. Although LE has achieved wide acceptance, surgical management of hyperparathyroidism has become increasingly disparate. This trend may highlight a need to define best-practice guidelines.
The Serum and Glucocorticoid Kinase sgk Increases the Abundance of Epithelial Sodium Channels in the Plasma Membrane of Xenopus Oocytes

The serum- and glucocorticoid-induced kinase (sgk) is a serine and threonine kinase that stimulates amiloride-sensitive sodium transport in Xenopus oocytes. Because aldosterone induces phosphorylation on serine/threonine (Ser/Thr) residues in the carboxyl termini of β and γ subunits of epithelial sodium channels (ENaCs) and causes an increase in thesgk transcript in mammalian and amphibian renal epithelial cells, it seems likely that sgk mediates the action of aldosterone to stimulate sodium transport. Experiments were performed in Xenopus oocytes to determine the mechanism by whichsgk increases sodium conductance by examining its effect on phosphorylation, kinetics, and membrane abundance of ENaC. Our results demonstrate that deletions of the carboxyl termini of the three subunits do not inhibit sgk-induced sodium current, indicating that the effect of sgk is not mediated via phosphorylation within the carboxyl termini of ENaC. They also show no evidence that sgk reduces the removal of ENaC from the plasma membrane because mutations of tyrosine residues in the sequences necessary for endocytosis and degradation did not affect the response to sgk. Further studies performed with the patch-clamp technique indicated that sgk did not increase the open probability or changed the kinetics of ENaC. These studies, however, showed a 3-fold increase in the abundance of ENaC in the plasma membrane in the presence of sgk compared with control. Together, the experiments indicate that sgk stimulates electrogenic sodium transport by increasing the number of ENaCs at the cell surface and suggest that sgk may mediate the early increase in aldosterone-induced sodium current.
Changes in the Phase and Amplitude of Polarized Light Reflected from a Film-Covered Surface and Their Relations with the Film Thickness

When polarized light is reflected from a film-covered surface, the variations in Δ and Ψ with the film thickness d are given by the exact equation of ellipsometry. Δ is the change in the difference between the phases of the parallel (p) and the perpendicular (s) components of the polarized light on reflection, and Ψ is the arc tangent of the factor by which the amplitude ratio of the p and s components changes on reflection. A first-order calculation of the exact equation is presented from which the two Archer equations for Ψ and Ψ (which are more accurate than those derived by Drude), relating their variations with the film thickness d, have been derived. Until now, both of these equations have been considered to be valid only in the thin-film region by most of the authors except Burge and Bennett who questioned the usefulness of the linear approximation for Ψ. It is shown that the Archer equation for Ψ is not valid in the thin-film region and a new generalized equation for Ψ is derived which is valid not only in the thin-film region (∼100 A) but also in certain ranges of the thick-film region. Further, a generalized approximate equation for Δ has also been derived which holds in the thin-film as well as in certain ranges of the thick-film regions. Experimental data to check the validity of the generalized approximate equation for Δ in the thick-film region are presented.
Quorum sensing in fungi: Q&A.

I know that the accumulation of certain molecules called ‘‘quorum-sensing factors’’ in bacteria, as cultures grow dense, can control group behavior and that these include virulence traits and the formation of drug-resistant microbial biofilms. I am familiar with some of the molecules that mediate the sensing of organism density such as homoserine lactones and peptides. However, I don’t know about such systems in fungi. What types of molecules are involved?
NEW DIRECTIONS FOR THE MÖSSBAUER EFFECT DATA CENTER

In an effort to become self-supporting, the Mossbauer Effect Data Center has devised a plan which requires publications of the Mossbauer Effect Reference and Data Journal rather than the annual Index. The details of the plan and descriptions of the "Data Journal" and functions of the Center follow.
The damping of surface gravity waves in a bounded liquid

In deducing the viscous damping rate in surface waves confined by side walls, Ursell found in an example that two different calculations, one by energy dissipation within and the other by pressure working on the edge of the side-wall boundary layers, gave different answers. This discrepancy occurs in other examples also and is resolved here by examining the energy transfer in the neighbourhood of the free-surface meniscus. With due care near the meniscus a boundary-layer–Poincare method is employed to give an alternative derivation for the rate of attenuation and to obtain in addition the frequency (or wave-number) shift due to viscosity. Surface tension is not considered.
A new wide-band Darlington amplifier

A wideband Darlington amplifier topology which is well suited for maximum-bandwidth, moderate-gain, matched-impedance applications is described. A test circuit using a silicon bipolar monolithic technology with an f/sub T/ of 9 GHz has been fabricated. Measured results show a 9.3 dB insertion gain and a 3.2 GHz bandwidth for the packaged device. >
Evidence for a Nonradical Pathway in the Photoracemization of Aryl Sulfoxides1

Photolysis of (RS,SC)-1-deuterio-2,2-dimethylpropyl p-tolyl sulfoxide provides mainly (SS,SC)-1-deuterio-2,2-dimethylpropyl p-tolyl sulfoxide at low conversion, though the other two stereoisomers are formed to smaller extents. Thus, the predominant process leading to sulfur inversion yields only sulfur inversion, without inversion of the adjacent CHD stereogenic center. This is taken as evidence for a mechanism for photochemical epimerization of sulfoxides that does not involve homolytic α-cleavage chemistry.
Discrete and continuous invariance in phyllotactic tilings.

Phyllotaxis refers to the arrangement of primordia (the first stage in the development of a structure such as a leaf) on plants and phyllotactic planforms refer to the shapes of the primordia in a phyllotactic arrangement. This paper focuses on invariances in phyllotactic planforms as the van Iterson parameter $\ensuremath{\Gamma}$---a measurement of the ratio of the size of the annular generative region at the plant tip where the patterns form to primordium area---varies. We demonstrate discrete invariance in phyllotactic planforms, by which we mean a similarity in the planform under a scaling $\ensuremath{\Gamma}\ensuremath{\rightarrow}\ensuremath{\Gamma}{\ensuremath{\phi}}^{n}$, where $\ensuremath{\phi}$ is the golden number and $n$ is an integer. Continuous invariance in planforms is then motivated by examples in which the shapes of primordia are homogeneous as $n$ varies over the real numbers. We also show how continuous invariance results from classical number-theoretical theorems on the approximation of irrational numbers (such as $\ensuremath{\phi}$) by rational numbers. We define these notions first for the underlying phyllotactic lattice and then for primordium shapes and amplitude equations resulting from partial differential equation (PDE) models.
Decreased helper-suppressor cell ratios following treatment with blood products: factor VIII and IX concentrates and fresh frozen plasma.

The immunologic status of three groups of multiply-transfused asymptomatic patients was evaluated. These included five with acquired inhibitors to factor VIIi treated with both factor VIII and factor IX concentrates (group A), seven with hemophilia B treated with factor IX concentrate (group B), and six with hemophilia B treated with fresh frozen plasma (group C). Mean T helper/T suppressor cell ratios (± S.E.M.) for the three groups were 0.72 ± 0.09, 1.35 ± 0.18 and 1.37 ± 0.12, respectively. All three differed significantly (p < 0.01) from the control mean ratio of 2.22 ± 0.16. In addition the mean ratio of group A patients was significantly different (p < 0.01) from that of groups B and C. An inverted ratio (< 1.00) was found in all group A patients and only one group B patient. An elevated IgG was found in 80 percent, 57 percent and 5 0 percent of each group, respectively. These immunological findings bear a striking resemblance to those of the acquired immunodeficiency syndrome (AIDS) of homosexuals, intravenous-drug abusers, Haitian immigrants, and factor-VIII-concentrate-treated hemophiliacs. Transmission via a blood borne infectious agent seems likely.
Stable Carbon Isotope Fractionation during Aerobic Biodegradation of Chlorinated Ethenes

Stable isotope analysis is recognized as a powerful tool for monitoring, assessing, and validating in-situ bioremediation processes. In this study, kinetic carbon isotope fractionation factors (e) associated with the aerobic biodegradation of vinyl chloride (VC), cis-1,2-dichloroethylene (cDCE), and trichloroethylene (TCE) were examined. Of the three solvents, the largest fractionation effects were observed for biodegradation of VC. Both metabolic and cometabolic VC degradation were studied using Mycobacterium aurum L1 (grown on VC), Methylosinus trichosporium OB3b (grown on methane), Mycobacterium vaccae JOB5 (grown on propane), and two VC enrichment cultures seeded from contaminated soils of Alameda Point and Travis Air Force Base, CA. M. aurum L1 caused the greatest fractionation (e = −5.7) while for the cometabolic cultures, e values ranged from −3.2 to −4.8. VC fractionation patterns for the enrichment cultures were within the range of those observed for the metabolic and cometabolic cultures (e = −4...
Angular Distribution of Pb L X-Rays Excited by 3 MeV Protons

We have measured the angular distribution of Pb Ll and L? x-rays in the case of lead where the targets were typically 100 ug/cm2 thick with a 400 ug/cM2 layer of silver evaporated on each side. Spectra were obtained at 25, 45, 65, 90, 115, 135 and 155 and ratios of Pb L x-rays to the isotropic Ag K x-rays were taken. The most readily interpretable case is Ll since this transition involves only the Lm subshell. Atter correcting for x-ray absorption in the target assuming it to be layered (i.e. neglecting diffision of the Ag in the Pb) we find a small deviation from isotropy, which is expected due to enhanced depopulation of M=0 substates at small impact parameter collisions. The velocity dependence of the alignment parameter A2 has been calculated using PWBA and screened as well as unscreened wave functions. Our results for A2 agree with these calculations. Further work is under consideration.
Ultrasonic Bonding of Membrane Electrode Assemblies for Low Temperature PEM Fuel Cells

Ultrasonic bonding of low temperature PEM membrane electrode assemblies has shown to cut the cycle time and energy input of manufacturing by over an order of magnitude each as compared to the industry standard of thermal pressing. Ultrasonic bonding uses high-frequency mechanical oscillations to convert electrical energy into heat energy which bonds the membrane electrode assembly components. This reduction in manufacturing resource requirement and time helps make fuel cell energy more economical as an alternative electrical power source. This paper will discuss ultrasonic and thermal bonding for low temperature Nafion fuel cells with 10 cm2 active area including process optimization and the effects of electrode type and membrane conditioning on ultrasonically bonded MEA performance.A design set of experiments was created for both ultrasonic bonding and thermal pressing process optimization using commercially available electrodes and conditioned Nafion 115 membrane. Analysis of Variance suggests that neither energy nor pressure have a statistically significant effect on the performance on ultrasonically bonded MEAs. For thermally pressed MEAs, temperature was found to have a significant effect on performance while pressure was not. Neither manufacturing technique found interaction effects to be statistically significant.Three different electrode compositions were tested on both ultrasonic and thermal MEA bonding methods. Electrodes investigated include two that were custom made in-house with catalyst loadings of 0.16 and 0.33 mg Pt/cm2, and one commercial electrode with 0.5 mg Pt/cm2. The lower loaded custom electrode had greater performance than the commercial electrode, which had higher platinum loading, indicating electrode architecture is an important factor in the performance of ultrasonically bonded MEAs.Membrane electrode assemblies made using Nafion membranes that were pretreated with a conditioning process showed decreased performance compared to MEAs ultrasonically bonded from dry, unconditioned membrane in short-term testing. MEAs thermally pressed with the custom made electrodes performed better with conditioned membranes while the commercial electrodes showed decreased performance with conditioning.Current electrodes have been optimized for thermal pressing as demonstrated by the two commercial electrodes having the largest performance decreases between thermally and ultrasonically manufactured MEAs. Future work includes intelligently designing an electrode for optimizing the ultrasonic bonding process for low temperature fuel cells to increase the performance of this manufacturing technique.Copyright © 2012 by ASME
Current Practice Patterns in Primary Hip and Knee Arthroplasty Among Members of the American Association of Hip and Knee Surgeons

A poll was conducted at the 2009 Annual Meeting of the American Association of Hip and Knee Surgeons to determine current practices among its members in primary total hip arthroplasty and total knee arthroplasty. This article summarizes the audience responses to a number of multiple choice questions concerning perioperative management and operative practice patterns and preferences including anesthetic choices, blood management, surgical approaches, implant selection, implant fixation, bearing surface choice, postoperative rehabilitation, recommended postoperative activity restrictions, and antibiotic prophylaxis.
Segregation of NaBr in NaBr/NaCl crystals grown from aqueous solutions: Implications for sea salt surface chemistry

Surface segregation of NaBr in mixed NaBr/NaCl crystals precipitated from aqueous solutions containing Br is investigated. Crystals were grown from solutions of a wide range of Br:Cl values and studied using x-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), energy-dispersive x-ray fluorescence (EDX), and atomic force microscopy (AFM). Results indicate that NaBr surface-segregates to cover 4–5% of the surface at the Br:Cl value found in sea water (1:660). The surface NaBr:NaCl values are ∼35 times higher those of the bulk crystals. The surface NaBr forms domains of average size 635 nm × 635 nm × 53 nm. Large areas of the surface contain NaCl with no detectable NaBr. Complete surface segregation of all Br found in sea salt particles is likely to occur, thereby making a greater amount of Br available for surface reactions with gas-phase constituents than would be predicted based on bulk composition.
Motion of Continuous Fibers through a Newtonian Resin for High Fiber Volume Fraction

This paper treats the motion of long, unidirectional, continuous fibers through a Newtonian resin. There is a consolidation force on the top row of fibers or an effective force on all the fibers due to their tension and curvature in a filament-wound cylinder. An asymptotic analysis for high fiber volume fraction is presented here. The present rigorous asymptotic solution leads to the same expressions as a previous applica tion of the lubrication approximation. The advantages of the asymptotic analysis are the definition of the error and the foundation for the proper treatment of more complex prob lems with several small parameters.
A comparative analysis of infant mortality in major Ohio cities: significance of socio-biological factors.

Abstract Using linked birth and infant death records for Ohio for the 1984–1987 birth cohorts, this paper examines differentials in neonatal, postneonatal, and infant mortality rates in four major Ohio cities. The specific cities studied were: Columbus, Cleveland, Cincinnati, and Toledo. It was found that, compared to Toledo, Cleveland had 51% higher risk of infant death, Cincinnati had 45% higher risk, Columbus had 13% higher risk of infant death. Although in each of these cities, black infants had significantly higher risk of death than white infants, controlling for race alone reduced but did not eliminate the infant mortality differentials among the cities. The results of the hazards analyses reveal that maternal education, marital status, maternal age, birth order, prenatal care, gestational age, and birth weight had a profound net impact on the risk of infant death and that, even after controlling for these and other maternal and infant characteristics, significant city differentials persisted in infant mortality. Similar patterns were observed for neonatal and postneonatal mortality, although the city differentials in postneonatal mortality were somewhat larger than those in neonatal mortality. Results of this study suggest that substantial reductions in infant and postneonatal mortality of these cities can be achieved by improving maternal education, reducing the incidence of teenage- and high-parity births, and providing better access to prenatal care. However, in order to understand and explain more fully the persisting geographic differences in infant mortality in Ohio, we need to consider the role of additional factors, particularly behavioral factors (e.g., maternal nutrition and substance abuse) and community-level factors such as poverty, unemployment, and racial segregation.
A priori modelling of an adiabatic spouted bed catalytic reactor

On a mis au point un modele de reacteur a priori pour un reacteur a lit jaillissant adiabatique. Ce modele utilise les equilibres de matiere et d'energie obeissant aux premiers principes pour predire les profils de concentration et de temperature dans la region du jet, de l'espace annulaire et de la fontaine. Les profils de circulation des particules et de porosite dans le jet sont calcules au moyen de techniques analytiques mises au point anterieurement. Les modeles de circulation des particules dans l'espace annulaire sont determines par une analyse des longueurs de trajet minimales. On a pu demontrer que le jet et la fontaine contribuaient de maniere significative a la conversion globale dans le lit. Les conversions predites et experimentales a des debits allant jusqu'a 1,2U ms montrent que la prolongation de la zone de reaction de la fontaine et l'augmentation de la circulation des particules avec l'augmentation de l'ecoulement a l'entree compensent la porosite moyenne plus elevee dans le jet et la fontaine. Les donnees experimentales confirment les resultats calcules pour un lit a jaillissement stable avec oxydation de CO sur un catalyseur Co 3 O 4 /α-Al 2 O 3 . Les effets du debit et de la concentration en reactif a l'entree sont confirmes
Coexistence of neurofilaments and vimentin in a neurone of adult mouse retina

Different classes of intermediate filaments are restricted to particular cell types1. For example, neurofilaments are found only in neurones2–6, whereas filaments that contain the protein vimentin, which were found in some cells of mesenchymal origin and some forms of glia4,5,7,8, are thought to be absent from mature neurones, and present only transiently in early embryonic neurones6,9. However, evidence is presented here of an exception to that rule in the outer plexif orm layer of the mouse retina. Double-labelling with antibodies to neurofilaments and vimentin showed that both types of intermediate filaments coexisted in the axonless horizontal cell of that retinal layer, recalling the previous notion that these cells are glial or intermediate between neuronal and glial (reviewed in ref. 10).
The SH2-containing protein-tyrosine phosphatase SH-PTP2 is required upstream of MAP kinase for early xenopus development

Abstract SH-PTP2, the vertebrate homolog of Drosophila corkscrew , associates with several activated growth factor receptors, but its biological function is unknown. We assayed the effects of injection of wild-type and mutant SH-PTP2 RNAs on Xenopus embryogenesis. An internal phosphatase domain deletion (ΔP) acts as a dominant negative mutant, causing severe posterior truncations. This phenotype is rescued by SH-PTP2, but not by the closely related SH-PTP1. In ectodermal explants, ΔP blocks fibroblast growth factor (FGF)- and activin-mediated induction of mesoderm and FGF-induced mitogen-activated protein (MAP) kinase activation. Our results indicate that SH-PTP2 is required for early vertebrate development, acting as a positive component in FGF signaling downstream of the FGF receptor and upstream of MAP kinase.
A role for DNA polymerase in the specificity of nucleotide incorporation opposite N-acetyl-2-aminofluorene adducts.

Abstract Escherichia coli DNA polymerase I (Klenow fragment), DNA polymerase α from both calf thymus and human lymphoma cells and DNA polymerase β from calf thymus and Novikoff hepatoma cells can incorporate nucleotides opposite N -guanin-8-yl-acetyl-2-aminofluorene in DNA. The polymerases incorporate dCTP opposite some AAF-dG § lesions when Mg 2+ is the divalent cation. Substitution of Mn 2+ for Mg 2+ broadens the specificity of insertion: E. coli DNA polymerase I (Klenow fragment) also inserts A, and at specific sites G or T; DNA polymerase α inserts any of the four dNTPs with A and C incorporated preferentially to G and T. Polymerase β is specific, inserting mainly C even in the presence of Mn 2+ . The K m for addition of dATP opposite a lesion by E. coli polymerase I (Klenow fragment) in the presence of Mn 2+ is about 0.5 m m . dNMPs increase the insertion of nucleotides opposite AAF-dG in the presence of Mg 2+ and increase both the rate and number of sites at which incorporation occurs in the presence of Mn 2+ . dNTPαS and recA protein increase only the insertion of C. We suppose that the incorporation of dCTP reflects normal base-pairing with the AAF-deoxyguanine in the anti conformation, whereas insertion of the other nucleotides (including some of the C) reflects insertion opposite the AAF adduct in its preferred syn conformation. The fact that the DNA polymerase plays a role in determining the specificity of insertion opposite a lesion terminating DNA synthesis suggests that the spectrum of base substitution mutagenesis seen in vivo may reflect the properties of the protein components, including the polymerase, involved in bypass synthesis.
A nonseparable Banach space not containing a subsymmetric basic sequence

We give an example of a nonseparable Banach space which does not contain a subsymmetric basic sequence. The space is the dual of a space constructed analogously to the James Tree space, using the Tsirelson space in place ofl 2.
Bimetallic palladium-platinum dendrimer-encapsulated catalysts.

We report the synthesis, characterization, and catalytic activity of bimetallic palladium−platinum dendrimer-encapsulated catalysts (DECs). These materials are prepared by co-complexation of different ratios of palladium and platinum salts to the interior tertiary amines of fourth-generation, hydroxyl-terminated poly(amidoamine) (PAMAM) dendrimers. Chemical reduction of these composites yields stable, fairly monodisperse, water-soluble bimetallic DECs having sizes on the order of 1.9 ± 0.4 nm. Evidence that these nanoparticles are bimetallic comes from single-particle X-ray energy dispersive spectroscopy (EDS) and catalysis experiments. The latter indicate that the hydrogenation rate of allyl alcohol is enhanced in the presence of the bimetallic nanoparticles compared to DECs containing only platinum or only palladium nanoparticles. EDS results indicate that the percentage composition of the bimetallics is reflected by the percentage of metal salts initially complexed with the dendrimer.
Fregean Senses, Modes of Presentation, and Concepts

Ever since Frege postulated senses in [1892] and conceived of them as (containing) modes of presentation, serious studies in the philosophy of language have often appealed to these entities. In the recent philosophy of language and mind, however, the notions of ‘mode of presentation’ and ‘concept’ have become more important. It seems fair to say that much of the theorizing involving senses, modes of presentation, and concepts has taken place at a very general level. Frege never told us what senses are; they were simply stipulated to be entities that play certain roles in his philosophy of language. Philosophers today still work with both senses and modes of presentation without having a systematic and viable theory of them. And although the notion of a concept has been employed in various ways, there are not all that many precise theories of concepts. In this paper, I try to clear away some of the mystery surrounding these three kinds of entities by offering a precise theory of them. The theory of Fregean senses developed in my previous work will be extended to yield a more general theory of modes of presentation and concepts. Modes of presentation and concepts will be identified, therefore, in terms
Measurements of the phase shift and reshaping of terahertz pulses due to total internal reflection

Using time-domain spectroscopic techniques with freely propagating electromagnetic beams of terahertz pulses, we have measured the phase shift and reshaping of subpicosecond pulses due to total internal reflection from a crystalline quartz prism. Our measured value of the phase shift is in excellent agreement with the theoretical prediction.
Acrylyl-Coenzyme A Reductase, an Enzyme Involved in the Assimilation of 3-Hydroxypropionate by Rhodobacter sphaeroides

ABSTRACT The anoxygenic phototroph Rhodobacter sphaeroides uses 3-hydroxypropionate as a sole carbon source for growth. Previously, we showed that the gene (RSP_1434) known as acuI, which encodes a protein of the medium-chain dehydrogenase/reductase (MDR) superfamily, was involved in 3-hydroxypropionate assimilation via the reductive conversion to propionyl-coenzyme A (CoA). Based on these results, we speculated that acuI encoded acrylyl-CoA reductase. In this work, we characterize the in vitro enzyme activity of purified, recombinant AcuI using a coupled spectrophotometric assay. AcuI from R. sphaeroides catalyzes the NADPH-dependent acrylyl-CoA reduction to produce propionyl-CoA. Two other members of the MDR012 family within the MDR superfamily, the products of SPO_1914 from Ruegeria pomeroyi and yhdH from Escherichia coli, were shown to also be part of this new class of NADPH-dependent acrylyl-CoA reductases. The activities of the three enzymes were characterized by an extremely low Km for acrylyl-CoA (
New seismic model of the upper mantle beneath Africa

We present a seismic model of the upper 400 km of the mantle beneath Africa and surrounding regions. This model is constructed by inverse modeling of fundamental mode Rayleigh wave phase velocities (40–200 s) for about 8000 propagation paths. Among the most pronounced anomalies are high shear velocity structures (as much as 6% higher than in the Preliminary Reference Earth model) beneath the West African, Congo, and Kalahari cratons that extend to about 250 km depth. These structures have near-vertical margins across which the shear velocity changes by as much as 6% over 500 km distance. Anomalous low shear velocities (3%–4% lower than in the Preliminary Reference Earth Model) structures are observed beneath the East African, Red Sea, and Gulf of Aden rifts, and beneath the northwestern Indian Ocean. These structures extend to a depth of at least 250 km. Our model cannot be reconciled with models that invoke a large number of plumes that have impinged on the base of the lithosphere, nor does our seismic model indicate that high-temperature, low-density material beneath the lithosphere is responsible for the uplift of southern Africa.
Multiparametric Detection In Modern Luminescence Spectrometry

Due to its sensitivity and selectivity, luminescence detection is often the choice in a wide variety of analytical applications. However, until recently only one parameter of luminescence was being monitored in a single experiment, for example, emission spectra scanned at a fixed single excitation wavelength, and decay of luminescence observed at a single wavelength of excitation and emission. In this paper we will present some of the recent developments that provide multiparametric detection of luminescence phenomena, for example, a complete intensity map of phosphorescence, simultaneously, at multiple wavelengths of excitation and emission over time. Another area involves the use of polarized radiation in effecting luminescence detection. We will discuss the instrumentation and data analysis for these kinds of experiments.
In-situ measurement of ethanol tolerance in an operating fuel cell

Ethanol is seen as an attractive option as a fuel for direct ethanol fuel cells and as a source for on-demand production of hydrogen in portable applications. While the effect of ethanol on in-situ electrode behavior has been studied previously, these efforts have mostly been limited to qualitative analysis. In alkaline fuel cells, several cathode catalysts, including Pt, Cu triazole, and Ag can be used. Here, we apply a methodology using a microfluidic fuel cell to analyze in-situ the performance of these cathodes as well as Pt anodes in the presence of ethanol and acetic acid, a common side product from ethanol oxidation. For a given concentration of ethanol (or acetic acid), the best cathode catalyst can be determined and the kinetic losses due to the presence of ethanol (or acetic acid) can be quantified. These experiments also yield information about power density losses from the presence of contaminants such as ethanol or acetic acid in an alkaline fuel cell. The methodology demonstrated in these experiments will enable in-situ screening of new cathodes with respect to contaminant tolerance and determining optimal operational conditions for alkaline ethanol fuel cells.
Irreversible Inactivation of Monoterpene Cyclases by a Mechanism-Based Inhibitor

Abstract Monoterpene synthases (cyclases) catalyze the divalent metal ion-dependent transformation of geranyl pyrophosphate to representatives of the various monocyclic and bicyclic skeletal types by an electrophilic reaction mechanism involving coupled isomerization and cyclization steps. An analogue of the geranyl substrate, in which the terminal gem -dimethyl groups were joined to form a cyclopropyl function (6-cyclopropylidene-3 E -methyl-hex-2-en-1-yl pyrophosphate) was shown to be a potent inhibitor of (−)-4 S -limonene synthase from Mentha spicata and of several other monoterpene cyclases from diverse plant species. Inhibition was concentration and time dependent (pseudo-first-order kinetics), as well as absolutely contingent on the presence of the divalent metal ion cofactor. A double reciprocal plot of k inactivation versus inhibitor concentration gave an apparent K i of approximately 0.3 μM and a maximum rate of inactivation of about 0.3 min −1 with limonene synthase. As expected for an active-site-directed process, the natural substrate, geranyl pyrophosphate, afforded protection against inactivation by the cyclopropylidene analogue. Selectivity of the inhibition was demonstrated with [1- 3 H]6-cyclopropylidene-3 E -methyl-hex-2-en-1-yl pyrophosphate by specific labeling of limonene synthase in crude enzyme extracts as evidenced by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, radio-fluorography, and immunoblotting. The radioactive cyclase-inactivator complex was formed with 1:1 stoichiometry and was stable to extended dialysis and boiling in 2% sodium dodecyl sulfate, suggesting irreversible covalent modification of the enzyme involving a chemical reaction between cyclase and inhibitor. Thermally denatured limonene synthase and synthase that had been inactivated with the histidine-directed reagent diethylpyrocarbonate or the cysteine-directed reagent p -hydroxymercuribenzoate (two reagents known to modify the active site of the enzyme and inhibit catalysis) were not labeled when treated with the [1- 3 H]-analogue, indicating that the functional enzyme was necessary to effect complex formation. All of the evidence is consistent with the analogue serving as a mechanism-based inactivator that must undergo both ionization-dependent isomerization and cyclization steps to reveal an allylic cation which alkylates the protein. In addition to furnishing supporting evidence for the electrophilic reaction sequence, this mechanism-based inactivator provides a powerful new approach for the examination of cyclase active sites.
Patch Size and Connectivity Thresholds for Butterfly Habitat Restoration

Abstract: Recovery of endangered species in highly fragmented habitats often requires habitat restoration. Selection of restoration sites typically involves too many options and too much uncertainty to reach a decision based on existing reserve design methods. The Fender's blue butterfly ( Icaricia icarioides fenderi) survives in small, isolated patches of remnant prairie in Oregon's Willamette Valley—a habitat for which 2 ha) connected (<1 km) patches have the highest restoration value. The dispersal model, however, suggests that small, connected patches have more restoration value than large, isolated patches, whereas the incidence function model suggests that size and connectivity are equally important. These differences stem from model assumptions. We used incidence functions to predict long-term, stochastic, steady-state conditions and dispersal simulations to predict short-term (25-year) colonization dynamics. To apply our results in the context of selecting restoration sites on the ground, we recommend selecting nearby sites when short-term colonization dynamics are expected to be an important aspect of a species' biology.
Conformational effects in the reversed-phase liquid chromatography of ribonuclease A

This paper examines the reversed-phase liquid chromatographic behavior of ribonuclease A (RNase) using an n-butyl chemically bonded phase and a gradient of 10 mM H3PO4 and l-propanol. At a column temperature of 25 degrees C, a broad band followed by an overlapped late-eluting sharp peak is observed. As the temperature is raised, the sharp peak grows at the expense of the broad band until at 37 degrees C, only a single narrow-eluting band is found. Using an absorbance ratio of A288/A254, it is demonstrated that the broad band represents a folded or native state of RNase and the late-eluting band a denatured state. Based on postcolumn absorbance ratio changes in the denatured state as a function of time and the known behavior of the protein, reversible refolding or renaturation is proposed to take place in solution. RNase is denatured upon adsorbing to the bonded phase, and upon migration down the column, reversible refolding takes place in the mobile phase. The relaxation time for native state formation is assumed to be comparable to the time spent by RNase in the mobile phase. As temperature is raised, both the native and denatured states exist at equilibrium in solution, thus slowing the refolding process, until at 37 degrees C only the denatured peak appears. Changes in peak shape with flow rate provide further evidence for this model. The use of HCl or H2SO4 instead of H3PO4 yields similar results except that the temperature at which only the denatured peak is observed follows the order of salt stabilization of the native state.
Epizootic pneumonia of bighorn sheep following experimental exposure to Mycoplasma ovipneumoniae.

Background Bronchopneumonia is a population limiting disease of bighorn sheep (Ovis canadensis). The cause of this disease has been a subject of debate. Leukotoxin expressing Mannheimia haemolytica and Bibersteinia trehalosi produce acute pneumonia after experimental challenge but are infrequently isolated from animals in natural outbreaks. Mycoplasma ovipneumoniae, epidemiologically implicated in naturally occurring outbreaks, has received little experimental evaluation as a primary agent of bighorn sheep pneumonia. Methodology/Principal Findings In two experiments, bighorn sheep housed in multiple pens 7.6 to 12 m apart were exposed to M. ovipneumoniae by introduction of a single infected or challenged animal to a single pen. Respiratory disease was monitored by observation of clinical signs and confirmed by necropsy. Bacterial involvement in the pneumonic lungs was evaluated by conventional aerobic bacteriology and by culture-independent methods. In both experiments the challenge strain of M. ovipneumoniae was transmitted to all animals both within and between pens and all infected bighorn sheep developed bronchopneumonia. In six bighorn sheep in which the disease was allowed to run its course, three died with bronchopneumonia 34, 65, and 109 days after M. ovipneumoniae introduction. Diverse bacterial populations, predominantly including multiple obligate anaerobic species, were present in pneumonic lung tissues at necropsy. Conclusions/Significance Exposure to a single M. ovipneumoniae infected animal resulted in transmission of infection to all bighorn sheep both within the pen and in adjacent pens, and all infected sheep developed bronchopneumonia. The epidemiologic, pathologic and microbiologic findings in these experimental animals resembled those seen in naturally occurring pneumonia outbreaks in free ranging bighorn sheep.
Problem‐based learning in the surgery clerkship: A change in philosophy

In the academic year 1989–1990, the Department of Surgery at the University of Kentucky College of Medicine introduced a modified third-year surgery clerkship. Its goals were to eliminate the lecture method of instruction, to involve students actively in the educational process, and to emphasize decision-making and problem-solving skills in the third year of medical school. Hands-on training in patient care procedures would be offered in a fourth-year acting internship after students had learned both problem-solving and life-long learning skills while concurrently developing a medical knowledge base. Students were removed from the traditional surgical service teams, since it was decided that team duties might be detrimental to educational goals. Problem-based tutorial sessions were designed, and a block of unscheduled time was provided for students to use in obtaining, exploring, and reflecting on medical information. Informal comparisons of students in the previous clerkships with those in the modified clerkship have noted positive changes in the students' intellectual maturity, motivation, enthusiasm, and time-management skills. Faculty and students have responded positively to the programs which are part of this innovative clerkship.
Multiscale segmentation for MRC document compression using a Markov random field model

The Mixed Raster Content (MRC) standard (ITU-T T.44) specifies a framework for document compression which can dramatically improve the compression/quality tradeoff as compared to traditional lossy image compression algorithms. The key to MRC's performance is the separation of the document into foreground and background layers, represented as a binary mask. In this paper, we propose a novel multiscale segmentation scheme based on the sequential application of two algorithms. The first algorithm, Cost Optimized Segmentation (COS), is a blockwise segmentation algorithm formulated in a global cost optimization framework. The second algorithm, Connected Component Classification (CCC), refines the initial segmentation by classifying feature vectors of connected components using a Markov random field (MRF) model. The combined COS/CCC segmentation algorithms are then incorporated into a multiscale framework in order to improve the segmentation accuracy of text with varying size.
Cost-Efficacy Issues in the Treatment of Peripheral Vascular Disease: Primary Amputation or Revascularization for Limb-threatening Ischemia

Controlling rising health care costs represents a major challenge to our society. Due to the aging of the population and the increasing number of patients with vascular disease, vascular specialists will be under mounting pressure by the managed care industry to provide the most cost-effective care for these patients. One particular controversy is whether to attempt revascularization in the patient with limb-threatening ischemia or to proceed directly with primary amputation. Although it has been assumed that the operative risk for revascularization procedures is high in elderly patients with a severely ischemic limb, mortality rates in the sickest patients are actually higher for amputation. It is also incorrect to assume that the duration of hospitalization is shorter for patients undergoing amputation than for patients undergoing revascularization. For both types of procedures, it is complications that prolong the length of hospital stay, and the rate of secondary amputation following a revascularization attempt is low (8.5%), compared with the rate of operative revision in patients following primary below-knee amputation (23%). The costs for revascularization and primary amputation are similar when the costs of a prosthesis and rehabilitative therapy are included in the calculations for amputation. The rationale for primary amputation assumes that patients will ambulate successfully with a prosthesis; however, many do not, and thus costs for institutionalization must be included in the equation. Long-term costs following revascularization were $28,374 in patients with a viable limb, compared with $56,809 in those undergoing secondary revascularization. The key to minimizing health care costs in this population is careful patient selection for initial revascularization, with aggressive long-term surveillance to ensure graft patency and limb viability.
YIELD AND TENDERNESS OF CURED CHICKEN ROLL PRODUCTS AS AFFECTED BY WATER ADDITION 1

Cured chicken roll products were prepared with either skinless breast meat of skinless dark meat from thighs and drumsticks. Similar products were also prepared from pork for comparison. Processing yields were higher for chicken breast meat than for other meat types when added water was greater than 30%. The yield of dark chicken meat products was always the lowest. Added water did not affect (P 0.05) the Warner-Bratzler shear values of the products. Dark chicken meat products were found to be the most tender, while those from pork were the least tender. Increase in mixing time increased (P 0.05) the processing yield of dark chicken meat products.