cssi/SciSciGPT-SciSciNet huggingface dataset:
Age-related changes in arachidonic acid metabolism of normal, leukemic and autoimmune strain mice

Spleen synthesis of prostaglandins (PGs) and thromboxane (Tx) was examined as a function of age for autoimmune, leukemic and normal mouse strains. Prostaglandin and thromboxane production from 14C-arachidonic acid was assessed from 20 minute synthesis by tissue homogenates. Values for young animals, six to 10 weeks of age, were compared to those for eight-to 12-month-old mice, except in the cases of the early autoimmune strain BXSB male and MRL/Ipr mice which were examined at five to seven months of age. Total eicosanoid synthesis, as well as PGF2α , PGE2, and PGD2 production showed, in general, a pattern of increase with age in nonautoimmune strain BALB/c, C57BI/6 and female BXSB mice. In contrast, PGE2 and PGF2α synthesis decreased in the autoimmune MRL/Ipr and male BXSB models and in the nonautoimmune, but lymphoma-developing AKR strain. The late autoimmune MRL/++ strain showed decreased PGE2 but no change in PGF2α with age. Age-related PGE2 and PGF2α changes were minimal in the nonautoimmune DBA/2 and in the late autoimmune PN strains. Thromboxane B2 appeared to be conserved in all strains studied. The results suggest that diminished spleen PG production with age is linked to development of autoantibodies and lymphoproliferative disorders. Further studies are necessary to establish whether decreased synthesis of immunoregulatory PGs plays a causal role in disease development or arises as a consequence of disease.
Late quaternary climate change in eastern North America: a comparison of pollen-derived estimates with climate model results

Abstract Late Quaternary pollen data from eastern North America and pollen-climate response surfaces provide tests of the climate simulations from Version 1 of the National Center for Atmospheric Research (NCAR) Community Climate Model (CCM1) for 21, 16, 14, 11, and 6 ka. The model results are also compared to those from Version 0 of the NCAR model (CCM0). In contrast to CCM0, CCM1 used a slab ocean model to compute sea surface temperatures, included a seasonal cycle, and computed soil moisture. It also used an improved set of boundary conditions from 21 to 6 ka. In eastern North America, CCM1 simulated lower temperatures at the last glacial maximum (LGM) 21,000 years ago than did CCM0 and therefore was in better agreement with the pollen data than the CCM0 simulations were. The simulations by CCM1 for mean July temperatures from 16 to 11 ka, however, were much higher than those by CCM0 and were higher than present for much of the area south of the Laurentide ice sheet. These simulated conditions differ markedly from those reconstructed from the pollen data, which indicate July temperatures significantly lower than present from 16 to 11 ka. At 6 ka, CCM1 simulated climate conditions similar to today and therefore not too different from those simulated by CCM0 or those inferred from the pollen data. For 6 ka in the upper Midwest, however, CCM1 simulated moisture conditions similar to present, which is an improvement over CCM0. However, the new simulation still does not match the drier-than-present conditions inferred from the pollen data. Detailed analysis of the circulation variables and the surface-energy-budget terms simulated by CCM1 show that both dynamic and thermodynamic factors contributed to the major discrepancy in July temperatures from 16 to 11 ka. The simulated glacial anticyclone created less cloudiness and rainfall south of the ice sheet, and these conditions allowed the increased summertime insolation from 16 to 11 ka to overheat the surface. The impact of the ice sheet on model dynamics therefore led to overestimation of summer temperatures south of the ice for this time period.
Evidences for complex formation between polymyxin B and lipopolysaccharides from Serratia marcescens

In vitro andin vivo complex formations of polymyxin B and lipopolysaccharides (LPS) from resistant and sensitive cells of Serratia marcescens were studied by poly-acrylamide gel electrophoresis in sodium dodecyl sulfate and electron microscopy. In vitro treatment of LPS from resistant cells with polymyxin B gave two populations of spherical complexes of different molecular weights as determined electrophoretically. Similar treatment of LPS from sensitive cells resulted in dissociation of the LPS-protein and subsequent complexing with the LPS moiety into stable spheres. In vivo treatment of resistant cells with polymyxin B resulted in LPS-polymyxin B complexes which were comparatively smaller and existed in two morphological forms: spheres and linear ribbons. LPS from the sensitive cells were degraded extensively into small rods and an amorphous mass by the in vivo polymyxin B treatment. In both systems, the electrophoretic results consistently matched the electron microscopic evidences for complex formation of LPS with polymyxin B. It is suggested that the disruptive effects of polymyxin B on LPS in the outer membrane of S. marcescens may be the explanation for the change in permeability barrier in the resistant cells and disorganization of the outer membrane and subsequent death in the sensitive cells. Furthermore, the ability of the LPS to complex with the polymyxin B molecules in resistant cells may be the basis of their resistance to the antibiotic.
Split step solution in the iteration of the beam propagation method for analyzing Bragg gratings

The split step method is applied to the iteration of the beam propagation method for analyzing the reflection of a laser beam by a volume Bragg grating. The application of the split step method is made possible by a way to properly treat the grating coupling terms in the paraxial wave equations. This method is demonstrated to be accurate in addition to efficient and robust. After this modification, the iteration of the beam propagation method is suitable for analyzing finite beams in volume Bragg gratings, for which the grating strength might be large. It is also suitable for analyzing Bragg gratings with nonuniform grating structures.
Editorial: A New Editor

Brian J. Thompson Editor Yes, indeed, we have made a few small changes to the journal Optical Engineering to launch the new year and Volume 30. The arrival ofanew editor is always a signal to make a few adjustments just to mark the changing of the guard-but we hope that on this occasion the changes are worthwhile in their own right...
RUBELLA-VIRUS/LEUCOCYTE INTERACTION AND ITS ROLE IN THE PATHOGENESIS OF THE CONGENITAL RUBELLA SYNDROME

Abstract The pathogenesis of persistent virus excretion in infants with the congenital rubella syndrome remains an immunological paradox. The presence of circulating 19S rubella-virus-neutralising antibody indicates that an immune response has been provoked by the virus and that tolerance in the usual sense of the word is not present. From the existing knowledge of those host factors involved in resistance to virus infection, a defect in cellular immune functions is postulated as underlying the failure of the tissues of some infants with the congenital rubella syndrome to terminate virus excretion. Attempts to demonstrate specific cellular immunity to rubella virus in vitro were unsuccessful, probably for the same reasons that cellular immunity may be deficient in vivo. Rubella-virus infection of human lymphocytes results in inability of these cells to undergo the metabolic changes requisite to their recruitment for immunological functions.
Nutrient dynamics in an oligotrophic arctic stream monitored in situ by wet chemistry methods

Diurnal trends in hydrochemical components of stream and river water, especially nutrients, is growing in interest as instrumentation capable of measuring at fine time scales becomes increasingly available. In this growing body of work, there are few studies that simultaneously report the dynamics of the major nutrients nitrate, phosphate, and ammonium through time. We used an in situ nutrient autoanalyzer to simultaneously measure nitrate, phosphate, and ammonium concentrations with wet chemistry methods in an arctic headwater stream. We operated the analyzer under two sampling regimes: (1) time interval (hourly) sampling to examine fine time scale nutrient dynamics and (2) continuous sampling (1 s data) to evaluate nutrient uptake from a pulse solute addition experiment. Hourly sampling showed inverse diurnal oscillating trends of nitrate and ammonium concentrations for several days during base flow conditions. We propose that this trend is a result of in-stream nutrient processing (autotrophic demand and nitrification) combined with increased lateral inputs of water from the active (thawed) soil layer at night, after evapotranspiration (ET) has ceased. Pulse additions of ammonium resulted in rapid increases in nitrate concentration, confirming potential magnitude of nitrification in this system. Phosphate concentrations were usually at or below detection limits, consistent with results from previous manual sampling of this stream. We conclude that as studies examining fine time scale nutrient trends in streams and rivers increase, the ability to examine the behavior of multiple nutrients simultaneously will be pertinent to assess the underlying mechanisms driving those trends.
Herpes simplex Virus a Protein ICP27 Can Inhibit or Augment Viral Gene Transactivation

Abstract Three of the five α (immediate early) gene products of herpes simplex virus, infected cell proteins (ICPs) 4, 0, and 27 play a role in the control of expression of viral β (delayed-early) and γ (late) genes. We report here that ICP27 can inhibit or augment the individual or combined abilities of ICP4 and ICPO to stimulate expression of chimeric genes containing viral gene promoters in a transient expression system. The specific effect of ICP27 was dependent on the viral gene promoter in the chimeric gene. ICP27 inhibited the ability of ICP4 and ICPO to activate some ,γ gene promoters but augmented their ability to activate other β or γ1 gene promoters when they were used in the target genes. Activation of the target genes by adenovirus ElA was not affected by ICP27 under the same conditions. ICP27 also repressed the ability of ICPO to stimulate expression of a chimeric gene containing an a gene promoter. Insertion of a termination codon in the middle of the ICP27 coding region severely reduced the inhibitory effect of the plasmid, indicating that this activity requires expression of functional ICP27 polypeptide. This report focuses on the ICP27 activity that negatively regulates ICP4 transactivation of a chimeric gene containing the upstream sequences of the HSV β gene ICP8. ICP27 decreased the level of mRNA initiated at the transcriptional start site of the ICP8 gene. The level of expression of the ICP4 gene was not changed by ICP27 but an alteration in the electrophoretic mobility of ICP4 expressed was observed. The modulatory effect of ICP27 on HSV transactivators may control the progress of the lytic cycle or provide a balance that varies indifferent cell types to affect whether lytic or latent infection ensues.
SU-GG-I-75: Discrepancies in Exposure Conditions for the EZ CR-DIN Phantom

Purpose: To determine whether discrepancies between exposure conditions recommended by the manufacturer of the EZ CR‐DIN phantom, by the DIN standard, and by a user affect evaluation of phantom images.Method and Materials: Computed radiographs(CR) of the Nuclear Associates EZ CR‐DIN phantom (Fluke Biomedical, Cleveland, OH) were acquired in triplicate for three exposure conditions: 72 kVp, the manufacturer's1; 80 kVp, the user's2; and 70 kVp plus 25 mm Al added filtration, the DIN specification3. Aluminum 1100‐H14 was substituted for 99.4% Al.4 kVp was verified non‐invasively. Projections of the phantom used AEC or manual technique on STVI imaging plates (IP) at 100 cm SID in the undertable Bucky tray. IPs were developed without delay with test menus in Semi‐automatic EDR mode using a FCR5000 (FujiFilm USA, Stamford, CT) calibrated for sensitivity and uniformity. DICOM images were transmitted to the PACS system using unity rescale slope and zero intercept. Images were exported from the PACS to a PC and analyzed using MATLAB (MathWorks, Natick, MA). Spectra for the three exposure conditions were generated using a semi‐empirical method.5 Results: Evaluation of low contrast features depended on exposure conditions, test menu selection, and subject contrast values. Contrast was exaggerated using the manufacturer's exposure conditions, but was indistinguishable between user and DIN conditions. Simulated spectra attenuated by the phantom indicated an average energy of 56, 61 and 59 keV for manufacturer, user, and DIN conditions. A high‐contrast test menu improved visibility of low contrast features but did not resolve all six steps of the dynamic range feature. Detected contrasts were more consistent with the manufacturer's subject contrast values than with those in the current DIN standard. Conclusion: Comparison of QC results among institutions depends on standard test objects imaged under standardized conditions. Differences in exposure and development conditions affect evaluation of test images.
Benzodiazepines antagonize central corticotropin releasing hormone-induced suppression of natural killer cell activity.

Abstract Benzodiazepines have anxiolytic properties and attenuate behavioral stress responses induced by corticotropin releasing hormone (CRH). To evaluate the effect of benzodiazepines on CRH-induced immune suppression, potent centrally acting benzodiazepines were administered prior to central infusion of CRH (i.c.v.; 1.0 μg). CRH induced a significant (P
Synthesis and Reactivity of a Molybdenum(IV) η4-Butadiene Complex

Molybdenum olefin complexes of the type [Mo(NPh)(η2-olefin)(o-(Me3SiN)2C6H4)] (olefin = propene (1a), isobutene (1b)) reacted with butadiene gas, affording [Mo(NPh)(η4-H2CCHCHCH2)(o-(Me3SiN)2C6H4)] (2), a molybdenum η4-butadiene complex. The crystal structure of 2 is reported. Treatment of 2 with 1 equiv of 2-butyne afforded (3) by 1H NMR spectroscopy. Two intermediates arising during the progress of the reaction were trapped at low temperature and characterized as the isomeric η3-allyl metallacycles [syn-Mo(NPh)(C(CH3)C(CH3)CH2CHCHCH2)(o-(Me3SiN)2C6H4)] and [anti-Mo(NPh)(C(CH3)C(CH3)CH2CHCHCH2)(o-(Me3SiN)2C6H4)] (4a,b, respectively) by NMR spectroscopy. Complex 3 was made independently by reaction of 1b with 1,2-dimethyl-1,4-cyclohexadiene, and the crystal structure of 3 is reported. Treatment of 2 with 2 equiv of 2-butyne afforded 1,2-dimethyl-1,4-cyclohexadiene as an organic product with concomitant formation of [Mo(NPh)(η2-alkyne)(o-(Me3SiN)2C6H4)] (alkyne = 2-butyne; 5) by 1H NMR spectroscopy. Reacti...
Quantitative assessment of dopamine D2 antagonist activity using invertebrate (Planaria) locomotion as a functional endpoint.

Abstract Introduction: Dopaminergic ligands, including drugs of abuse, modulate the locomotor activity of planarians and induce characteristic abnormal patterns of motility at high doses. It has been presumed that the effect is related to dopamine receptors based on ligand specificity and effects on second messenger levels. However, to date, the measured changes have been mostly qualitative in nature and it is not completely clear that the effect is related to stereospecific receptor mechanisms. Methods: The present study addressed these issues by devising a convenient and sensitive metric (locomotor velocity, pLMV) and applied the method to test Planaria enantiomer-sensitivity to a dopamine D2-receptor antagonist. Results: pLMV was remarkably constant over the observation period and established a stable baseline against which to study and quantitate pharmacologic intervention. Further, S(−)-sulpiride at low doses (10−10 to 10−8 M) attenuated pLMV in a dose-dependent manner, but R(+)-sulpiride was only 1/25th as potent. Discussion: The new methodology thus provides a method for quantifying actions of D2 ligands in a simple in vivo system.
(Na + + K + )-ATPase activity in the dog submandibular gland.

Abstract Microsomes prepared from dog submandibular glands contain a (Na+ + K+)-activated Mg2+-dependent ATPase (ATP phosphohydrolase, EC 3.6.1.3) with a relatively high specific activity (105 μmoles Pi × mg protein−1 × hr−1). In the range tested, maximal activation of the enzyme was attained at Na+ and K+ concentrations of 200 and 10 mM respectively in the presence of 5 mM Mg2+, Rb+. Cs+, NH4+, Li+, and choline could not substitute for Na+, but could partially substitute for K+ ions. Chloride was not essential as an anion, but could be substituted for by nitrate, bromide, iodide or sulphate without loss of activity. The pH optimum for the enzyme was 7.2 and the concentration of ouabain for half-maximal inhibition of enzyme activity was 2 × 10−7 M.
Water under the BAR

Many cellular processes require the generation of highly curved regions of cell membranes by interfacial membrane proteins. A number of such proteins are now known, and several mechanisms of curvature generation have been suggested, but so far a quantitative understanding of the importance of the various potential mechanisms remains elusive. Following previous theoretical work, we consider the electrostatic attraction that underlies the scaffold mechanism of membrane bending in the context of the N-BAR domain of amphiphysin. Analysis of atomistic molecular dynamics simulations reveals considerable water between the membrane and the positively charged concave face of the BAR, even when it is tightly bound to highly curved membranes. This results in significant screening of electrostatic interactions, suggesting that electrostatic attraction is not the main driving force behind curvature sensing, supporting recent experimental work. These results also emphasize the need for care when building coarse-grained models of protein-membrane interactions. These results are emphasized by simulations of oligomerized amphiphysin N-BARs at the atomistic and coarse-grained level. In the coarse-grained simulations, we find a strong dependence of the induced curvature on the dielectric screening.
Morphological adaptations of hot springs panic grass (Dichanthelium lanigunosum var sericeum (Schmoll) to thermal stress

Although growth and productivity of most crops are significantly reduced by exposure to temperatures in excess of 35 °C, some plants thrive in geothermally heated soils characterized by chronic temperatures in excess of 40 °C. The morphological adaptations that enable these plants to colonize thermal environments are poorly understood. We characterized trichome development, silica accumulation, stomatal density, and waxy cuticle development in populations of Dichanthelium lanuginosum var sericeum (Schmoll) isolated from thermal and non-thermal environments to determine whether morphological changes existed in populations adapted to thermal environments. Plants isolated from thermal environments of Yellowstone National Park developed an extensive series of trichomes when exposed to chronic temperatures of 45/35 °C (day/night). In contrast, isolates from non-thermal environments of western Oregon showed minimal trichome development during exposure to the elevated temperatures. Leaves that developed during exposure to elevated temperatures had reduced thickness, though the reduction was less marked in plants from populations isolated from thermal environments. Plants isolated from thermal environments also had greater numbers of stomata on adaxial leaf surfaces relative to biotypes isolated from non-thermal environments. These results suggest phenotypic characteristics that may be useful in selection of new varieties of crop species with improved tolerance to supraoptimal temperatures.
Elastin in large artery stiffness and hypertension

Large artery stiffness, as measured by pulse wave velocity, is correlated with high blood pressure and may be a causative factor in essential hypertension. The extracellular matrix components, specifically the mix of elastin and collagen in the vessel wall, determine the passive mechanical properties of the large arteries. Elastin is organized into elastic fibers in the wall during arterial development in a complex process that requires spatial and temporal coordination of numerous proteins. The elastic fibers last the lifetime of the organism but are subject to proteolytic degradation and chemical alterations that change their mechanical properties. This review discusses how alterations in the amount, assembly, organization, or chemical properties of the elastic fibers affect arterial stiffness and blood pressure. Strategies for encouraging or reversing alterations to the elastic fibers are addressed. Methods for determining the efficacy of these strategies, by measuring elastin amounts and arterial stiffness, are summarized. Therapies that have a direct effect on arterial stiffness through alterations to the elastic fibers in the wall may be an effective treatment for essential hypertension.
Finite Basis Problem for Semigroups of Order Five or Less: Generalization and Revisitation

A system of semigroup identities is hereditarily finitely based if it defines a variety all semigroups of which are finitely based. Two new types of hereditarily finitely based identity systems are presented. Two of these systems, together with eight existing systems, establish the hereditary finite basis property of every semigroup of order five or less with one possible exception.
The effects of alterations in the suspending medium on low temperature activation of spores of Bacillus stearothermophilus NGB101

The effects of eight different sodium salts on the activation of spores of Bacillus stearothermophilus NGB101 at 30°C were examined. Sodium nitrite was a potent activator spores of NGB101. Complete activation of spore populations was obtained after 6 h or less at 30°C. Activation of spores of NGB101 in solutions of sodium nitrite, like activation in distilled water, was temperature dependent, with optimal activation at 30°C. While a potent activator of spores of NGB101 at 30°C, sodium nitrite was ineffective as an initiator of germination at 65°C. Activation of spores of NGB101 produced marked increases in colony forming spores compared with nonactivated populations. Spore populations activated in solutions of sodium nitrite gave higher plate counts compared with spores activated in distilled water.
Momentum measurements of electrons in a heavy-liquid bubble chamber

Abstract The momentum reconstruction of high-energy electrons in a heavy-liquid bubble chamber is studied using Monte Carlo simulations. The energies of the simulated electrons used in this study ranged from 10 to 100 GeV. The angular distribution and multiplicity of converted bremsstrahlung gammas is given as a function of energy for these events. An energy-independent method of correcting for poor measurements due to hard bremsstrahlung is found. This method consists of summing the reconstructed electron momentum and the momentum of the highest energy converted gamma.
Cascaded Perforates as One-Dimensional, Bulk Absorbers

Porous cell honeycomb liners for aircraft engine nacelles offer the possibility of exploiting extended reaction effects to improve liner attenuation bandwidth as generally attributed to the performance of bulk absorbers. This paper describes an analytical procedure, starting with an impedance prediction model for a single perforated plate, to estimate the bulk-absorber parameters for a cascade of such perforates - a first step to modeling a porous wall honeycomb structure. The objective is to build confidence in a lumped element impedance model, when applied to a uniformly-spaced set of porous plates to predict its .bulk. absorber properties. The model is based upon a modified version of the two-parameter flow resistance model of the form A + BV(sub inc), where A and B are physics-based, semi-empirical parameters that are adjusted to provide an optimum fit to a composite dataset from three plate porosities of 2.5, 5 and 10%. The composite dataset is achieved by reformulating the two-parameter flow resistance model into a .reduced pressure drop coefficient. dependency on perforate hole Reynolds number. The resulting impedance model is employed to calculate surface impedance spectra for N and 2N-layer perforate cascades. The well-known two-thickness method for experimental determination of bulk-absorber parameters is then applied to these .synthesized. data sets to predict the characteristic impedance and propagation constant for the perforate cascades. These results are then compared with experimental results reported in a companion paper.
Multiobjective Optimization for Model Selection in Kernel Methods in Regression

Regression plays a major role in many scientific and engineering problems. The goal of regression is to learn the unknown underlying function from a set of sample vectors with known outcomes. In recent years, kernel methods in regression have facilitated the estimation of nonlinear functions. However, two major (interconnected) problems remain open. The first problem is given by the bias-versus-variance tradeoff. If the model used to estimate the underlying function is too flexible (i.e., high model complexity), the variance will be very large. If the model is fixed (i.e., low complexity), the bias will be large. The second problem is to define an approach for selecting the appropriate parameters of the kernel function. To address these two problems, this paper derives a new smoothing kernel criterion, which measures the roughness of the estimated function as a measure of model complexity. Then, we use multiobjective optimization to derive a criterion for selecting the parameters of that kernel. The goal of this criterion is to find a tradeoff between the bias and the variance of the learned function. That is, the goal is to increase the model fit while keeping the model complexity in check. We provide extensive experimental evaluations using a variety of problems in machine learning, pattern recognition, and computer vision. The results demonstrate that the proposed approach yields smaller estimation errors as compared with methods in the state of the art.
Decoding neuroproteomics: integrating the genome, translatome and functional anatomy

The immense intercellular and intracellular heterogeneity of the CNS presents major challenges for high-throughput omic analyses. Transcriptional, translational and post-translational regulatory events are localized to specific neuronal cell types or subcellular compartments, resulting in discrete patterns of protein expression and activity. A spatial and quantitative knowledge of the neuroproteome is therefore critical to understanding both normal and pathological aspects of the functional genomics and anatomy of the CNS. Improvements in mass spectrometry allow the profiling of proteins at a sufficient depth to complement results from high-throughput genomic and transcriptomic assays. However, there are challenges in integrating proteomic data with other data modalities and even greater challenges in obtaining comprehensive neuroproteomic data with cell-type specificity. Here we discuss how proteomics should be exploited to enhance high-throughput functional genomic analysis by tighter integration of data analyses. We also discuss experimental strategies to achieve finer cellular and subcellular resolution in transcriptomic and proteomic studies of neural tissues.
Longitudinal Study of Recruitment and Retention in Small Community Homes Supporting Persons With Developmental Disabilities

Variables associated with turnover in 110 small Minnesota group homes supporting people with developmental disabilities between December 1993 and December 1996 were examined. Common staffing problems included recruiting qualified workers (reported by 57% of supervisors) and staff turnover (44%). Turnover for direct support professionals was 46%. Of workers who left, 45% left within 6 months of hire, and another 23%, between 6 and 12 months. A multiple regression analysis (with 11 variables) accounted for 34% of the variability in facility turnover rates. Variables contributing significantly to the prediction of higher turnover included greater support needs of residents, lower starting pay, less tenured supervisors, and fewer direct support professionals eligible for paid leave. Implications for practice, research, and policy were discussed.
Electron energy loss for two transition metal-transition metal glasses

Abstract Electron energy loss data are reported for metallic glasses Fe0.92Zr0.08 and Ni0.5Zr0.5. These data document the sensitivity of the spectra to sample thickness and suggest studies of metallic glasses require samples that are nearly 1 2 an order of magnitude “thinner” than crystalline alloys. Each electron energy loss spectrum has a dominant loss near 23–25 eV which is similar to the loss function of the pure 3-d metal. This lack of a shift in the location of the dominant loss challenges any simple model of plasmon behavior. The M23 core losses are visible in the “thinner” samples and, in agreement with earlier studies on metal-metalloid glasses, no measureable chemical shift is observed.
A Fabry-Perot interferometer for accurate measurement of temporal changes in stellar Doppler shift

The scrambling of incident light by an optical filter, and the stability obtainable through wavelength calibration by means of a tilt-tunable Fabry-Perot etalon, allow the accurate observation of Doppler shift changes in stellar absorption lines. Distinct, widely spaced monochromatic images of the entrance aperture are formed in the focal plane of the camera through a sampling of about 350 points on the profile of the stellar spectrum by successive orders of interferometric transmission through the etalon. Changes in Doppler shift modify the relative intensities of these images, in proportion to the slope of the spectral profile at each point sampled.
Testing the Correlation between Spiral Arm Pitch Angle and Central Black Hole Mass

In order to address the “cosmic downsizing problem,” or the underpopulation of highly massive quasars in the current epoch, the Arkansas Galaxy Evolution Survey is exploring a correlation, the M‐P relation, between the pitch angle of a galaxy’s spiral arms and the mass of its central supermassive black hole (SMBH). The goal is to add to the census of SMBH masses using only images, without relying on spectra. We present the null correlation between the pitch angle of spiral arms and redshift. The data set includes 225 galaxies from the GOODS North and South fields with redshifts out to z∼1.2. There does not appear to be any dependence of pitch angle on redshift. Consequently, if the relationship between pitch angle and SMBH mass has not evolved since z∼1.2, then the mean mass of SMBH has also remained constant. If, on the other hand, the relationship has evolved, then the mean mass has evolved inversely with the relationship. This conclusion is subject to further studies on possible selection effects. Addi...
Vibrational and electronic heating in nanoscale junctions

Surface-enhanced Raman emission can measure the effective temperatures both of the vibrational modes and the flowing electrons in a nanoscale junction.
Concepts and Epistemic Individuation

Christopher Peacocke has presented an original version of the perennial philosophical thesis that we can gain substantive metaphysical and epistemological insight from an analysis of our concepts. Peacocke's innovation is to look at how concepts are individuated by their possession conditions, which he believes can be specified in terms of conditions in which certain propositions containing those concepts are accepted. The ability to provide such insight is one of Peacocke's major arguments for his theory of concepts. I will critically examine this “fruitfulness” argument by looking at one philosophical problem Peacocke uses his theory to solve and treats in depth. Peacocke (1999, 2001) defines what he calls the “Integration Challenge.” The challenge is to integrate our metaphysics with our epistemology by showing that they are mutually acceptable. Peacocke's key conclusion is that the Integration Challenge can be met for “epistemically individuated concepts.”A good theory of content, he believes, will close the apparent gap between an account of truth for any given subject matter and an overall account of knowledge. I shall argue that there are no epistemically individuated concepts, and shall critically analyze Peacocke's arguments for their existence. I will suggest more generally that the possession conditions of concepts and their principles of individuation shed little light on the epistemology or metaphysics of things other than concepts. My broader goal is to shed light on what concepts are by showing that they are more fundamental than the sorts of cognitive and epistemic factors a leading theory uses to define them.1
Association Between Practice Setting and Pediatric Hospitalist Career Satisfaction

Background: Pediatric hospital medicine has become a viable long-term career choice. To retain qualified physicians, both academic and community hospital leaders seek to improve their job satisfaction. Objective: The goal of this study was to determine whether practice in a community versus academic setting is associated with pediatric hospitalists’ career satisfaction. Methods: The study was based on data from an anonymous electronic cross-sectional survey sent to the American Academy of Pediatrics Section on Hospital Medicine Listserv between November 2009 and January 2010. Questions were rated on a standard 5-point Likert scale. A total career satisfaction score was calculated for each respondent by summing across all 23 questions. Multivariate logistic regression was conducted to assess job satisfaction according to practice setting. Results: A total of 222 pediatric hospitalists responded. Sixty-six percent of respondents practiced in an academic setting and 34% in a community hospital. Fifty-eight percent of academic and 42% of community hospitalists were satisfied with their careers, defined as a mean per-question Likert score ≥4. Adjusting for gender, average daily census, percentage of complex patients, years as a hospitalist, and years since residency graduation, academic hospitalists were more likely than community hospitalists to be satisfied with their careers (adjusted odds ratio: 2.43 [95% confidence interval: 1.25–4.72]; P = .009). Conclusions: Pediatric hospitalists practicing in academic settings seem more likely to be satisfied with their careers than those in a community hospital. Overall, however, there is room for improvement in career satisfaction for both groups. Further study is warranted to confirm and clarify these findings on a larger scale, perhaps with oversampling of community hospitalists.
Mechanical and Thermoviscoelastic Behavior of Clay/Epoxy Nanocomposites

The study of organic-inorganic nanocomposites has become relevant in recent years since these materials exhibit synergistic properties derived from the two components. Thermosetting polymers like epoxies that have high mechanical properties provide a baseline for further improvement with the addition of nanoclay particles. These nanocomposites can be used as the matrix of a fiber reinforced composite and lead to higher matrix dominated mechanical properties including elastic modulus, strength and fracture toughness. This study concentrates on the mechanical and thermoviscoelastic properties in the glassy regime of nanocomposites prepared by direct mixing. The elastic modulus of the nanocomposites was found to improve with respect to the pure epoxy modulus at the expense of both tensile strength and ductility regardless of clay content. The glass transition temperature was also found to decrease as well. The morphology of the nanocomposites was studied and correlated with the aforementioned properties.
Onset of Buckling in Drying Droplets of Colloidal Suspensions

Minute concentrations of suspended particles can dramatically alter the behavior of a drying droplet. After a period of isotropic shrinkage, similar to droplets of a pure liquid, these droplets suddenly buckle like an elastic shell. While linear elasticity is able to describe the morphology of the buckled droplets, it fails to predict the onset of buckling. Instead, we find that buckling is coincident with a stress-induced fluid to solid transition in a shell of particles at a droplet's surface, occurring when attractive capillary forces overcome stabilizing electrostatic forces between particles.
Concatenated spectrum multi-band TOA estimation

This paper investigates Time-of-Arrival (TOA) estimation performance of a non-contiguous multi-band radio considering the realistic assumption of frequency selective channel across all bands. It is depicted that the resulted TOA performance is comparable to that of utilizing a bandwidth equivalent to the addition of all available frequency bands. A high resolution TOA estimation architecture is proposed that is based on concatenating the estimated channels across sub-bands all sub-bands and applying a TOA estimation method to the whole available spectrum. The Cramer-Rao Bound (CRB) of the TOA estimation for this method is computed. Minimum Mean Square Estimation (MMSE) algorithm is applied to evaluate the performance of the proposed system. Simulations are conducted to study the performance in terms of the variance-of-error.
Cu Pillar and μ-bump electromigration reliability and comparison with high pb, SnPb, and SnAg bumps

Failures due to Electromigration (EM) in flip-chip bumps have emerged as a major reliability concern due to potential elimination of Pb from flip-chip bumps and a continuous drive to increased IO density resulting in a reduction of bump pitch and size. Additionally, the rapid development and implementation of 3D IC structures introducing new interconnects (μ-bumps, RDL, microvias, and TSVs) at much finer geometries, raises concerns about electromigration and current carrying capacity of these interconnects. This paper presents the results of multiple EM studies on Cu Pillar, High Pb, SnAg, eutectic SnPb Flip Chip bumps and μ-bumps. A special test vehicle was designed to get a head-to-head comparison of Cu Pillar EM with that of solder bumps. Tests are being conducted using three current levels and three temperatures to estimate Black's Equation parameters. A separate test vehicle is also being tested using 5 combinations of current and temperature to estimate the current carrying capacity of Cu-SnAg-Cu μ-bumps of 25um diameter. More than 8000 hours of testing is completed on flip chip solder bump and Cu Pillar, showing Cu Pillars as having the best reliability amongst the four bump metallurgies. The worst reliability was observed for High Pb bumps followed by eutectic SnPb eut and SnAg bumps. The Cu-SnAg-Cu μ-bump structure has been tested for 5500+ hours without any failures. The paper provides the detailed test matrix, failure data, failure analysis, and an estimation of Black's Equation parameters for some of the above configurations on test.
Application of SOM to analysis of Minnesota soil survey data

This paper describes data-analytic modeling of the Minnesota soil chemical data produced by the 2001 metro soil survey. The chemical composition of the soil is characterized by the concentration of many metal and non-metal constituents, resulting in high-dimensional data. This high dimensionality and possible unknown (nonlinear) correlations in the data make it difficult to analyze and interpret using standard statistical techniques. This paper applies Self Organizing Map (SOM), to present the high-dimensional soil data in a 2D format suitable for human understanding and interpretation. This SOM representation enables analysis of the soil chemical concentration trends within the Twin Cities Metropolitan area of Minnesota. These trends are important for various Minnesota regulatory agencies concerned with the concentration of polluting chemical elements due to human activities.
Recommendations for engineering doctoral education: Design of an instrument to evaluate change

In recent years, many studies and reports have highlighted concerns and problems with engineering doctoral degree recipients. Criticisms have come from professionals in both industry and academia, as well as from current and former Ph.D. students. Given the dissatisfaction of a variety of stakeholders, there have been calls from professional societies, disciplinary bodies and federal agencies to improve doctoral granting programs across the U.S. and to educate Ph.Ds. who are equipped with skills and attributes necessary to meet the highly-competitive and rapidly changing 21st century workforce [1, 2]. Within this context, this study focuses on the perspectives of working professionals from both academia and industry. Preliminary findings were obtained from one-on-one interviews with forty engineering Ph.D. holders who are from industry and/or academia. They recommended practical measures for engineering doctoral students to obtain desired characteristics upon graduation. Using the preliminary results, the work in progress precludes the design of an instrument to evaluate on-going changes to different aspects of doctoral education. The instrument will serve as a useful tool to understand the degree and scope of changes in engineering doctoral program. Portions of the instrument informed from these recommendations are provided.
Elementary Local Properties of Holomorphic Functions

In §1 and §2 of this chapter we present the standard local properties of holomorphic functions and maps which are obtained by combining basic one complex variable theory with the calculus of several (real) variables. The reader should go through this material rapidly, with the goal of familiarizing himself with the results, notation, and terminology, and return to the appropriate sections later on, as needed. The inclusion at this stage of holomorphic maps and of complex submanifolds, i.e., the level sets of nonsingular holomorphic maps, is quite natural in several variables. In particular, it allows us to present elementary proofs of two results which distinguish complex analysis from real analysis, namely: (i) the only compact complex submanifolds of ℂ n are finite sets, and (ii) the Jacobian determinant of an injective holomorphic map from an open set in ℂ n into ℂ n is nowhere zero. Section 3, which gives an introduction to analytic sets, may be omitted without loss of continuity. We have included it mainly to familiarize the reader with a topic which is fundamental for many aspects of the general theory of several complex variables, and in order to show, by means of the Weierstrass Preparation Theorem, how algebraic methods become indispensable for a thorough understanding of the deeper local properties of holomorphic functions and their zero sets.
Why Here and Why Now? Teacher Motivations for Unionizing in a New Orleans Charter School.

The rigidity of teachers unions has been given as a primary reason for their lack of representation among America’s rapidly growing, although still relatively small, charter school sector. In the case of post-Hurricane Katrina New Orleans, the city rapidly converted from a union-backed teacher workforce to a largely nonunionized charter school workforce in the years following state takeover and charter conversion. This makes the recent emergence of two single-school unions in charter schools there worthy of study. As the teachers attempt to organize single-school unions in a nearly all charter school system, what are their motivations? This case study of one of New Orleans’ emerging charter school unions found that pay inequities, job insecurity, a lack of teacher voice in school-level decisions, and a culture of compliance, all motivated teachers to seek unionization. Teachers hoped to promote equity and teacher involvement with their union, but the organizing effort did strain some relationships, partic...
Mechanical properties of computationally designed novel carbon enriched Si1−xCx ceramics: A molecular dynamics simulation study

Abstract Silicon Carbide (SiC) exhibits excellent mechanical, thermal and electrical properties. Low fracture toughness is one of the limiting properties of SiC that hinders its widespread applications. Recent studies suggest that controlled alteration of local micro-structure may lead to dislocation nucleation in certain SiC poly-types. Here, we report classical molecular dynamics simulations results to demonstrate mechanical behavior of a new type SiC-based “C enriched” ceramics where certain Si atoms are substituted by C atoms. We studied four different systems with different fraction of “C” enrichment, namely 10%, 20%, 30% and 40%. Thermodynamic viability of such novel micro-structures have been studied recently (Adnan and Ferdous, 2015). Significant effects of “C” enrichment on the tensile and shear properties of the new ceramic materials have been observed. Compared to pure SiC, the tensile strengths of enriched systems always increase but to a different extent depending on the amount of enrichment. Shear strengths, however, tend to decrease with increase in carbon enrichment until enrichment is 40%. The elastic constants C 11 and C 44 were measured and both increase significantly with carbon enrichment. The area under the stress–strain tensile and shear curves have been estimated to assess the tensile and shear toughness properties and it has been found that both types of toughness increase significantly with carbon enrichment.
Sperm motility in the rat epididymis.

The development of sperm motility was studied in rats with ligated caput epididymidis to determine whether intrinsic or extrinsic factors were involved. Most sperm moved in circular patterns; sperm from the ligated caput showed more motility after 7 to 10 days retention but none showed motion of the mature progressive type. Sperm from caput ligated at both ends showed immature motility. It is concluded that in the rat posttesticular age (intrinsic factors) are not sufficient for development of mature sperm motility. An extrinsic factor in the epididymal environment seems to be necessary.
Nondeterministic multiscale modeling of biomimetic crack self-healing in nanocrystalline solids under mechanical loading

A nondeterministic multiple scale approach based on numerical solution of the Monte-Carlo master equation coupled with a standard finite-element formulation of material mechanics is presented. The approach is illustrated in application to the long-term evolutionary processes of self-diffusion, precipitation and crack/void healing in nanocrystalline fcc and bcc solids. Effect of static and dynamic loading patterns on the crack healing rates are investigated. The approach is widely applicable to the modeling and characterization of advanced functional materials with evolutionary internal structure, as well as emerging behavior in materials systems.