cssi/SciSciGPT-SciSciNet huggingface dataset:
CLOSE STELLAR ENCOUNTERS IN YOUNG, SUBSTRUCTURED, DISSOLVING STAR CLUSTERS: STATISTICS AND EFFECTS ON PLANETARY SYSTEMS

Both simulations and observations indicate that stars form in filamentary, hierarchically clustered associations, most of which disperse into their galactic field once feedback destroys their parent clouds. However, during their early evolution in these substructured environments, stars can undergo close encounters with one another that might have significant impacts on their protoplanetary disks or young planetary systems. We perform N-body simulations of the early evolution of dissolving, substructured clusters with a wide range of properties, with the aim of quantifying the expected number and orbital element distributions of encounters as a function of cluster properties. We show that the presence of substructure both boosts the encounter rate and modifies the distribution of encounter velocities compared to what would be expected for a dynamically relaxed cluster. However, the boost only lasts for a dynamical time, and as a result the overall number of encounters expected remains low enough that gravitational stripping is unlikely to be a significant effect for the vast majority of star-forming environments in the Galaxy. We briefly discuss the implications of this result for models of the origin of the solar system, and of free-floating planets. We also provide tabulated encounter rates and orbital element distributions suitable for inclusion in population synthesis models of planet formation in a clustered environment.
The synthesis and study of side‐chain lactam‐bridged peptides

Side-chain lactam bridges linking amino acid residues that are spaced several residues apart in the linear sequence offer a convenient and flexible method for introducing conformational constraints into a peptide structure. The availability of a variety of selectively cleavable protecting groups for amines and carboxylic acids allows for several approaches to the synthesis of monocyclic, dicyclic, and bicyclic lactam-bridged peptides by solid-phase methods. Multicyclic structures are also accessible, but segment-condensation syntheses with solution-phase cyclizations are most likely to provide the best synthetic approach to these more complex constrained peptides. Lactam bridges linking (i, i + 3)-, (i, i + 4), and (i, i + 7)-spaced residue pairs have all proven useful for stabilization of alpha helices, and (i, i + 3)-linked residues have also been demonstrated to stabilize beta-turns. These structures are finding an increasing number of applications in protein biology, including studies of protein folding, protein aggregation, peptide ligand-receptor recognition, and the development of more potent peptide therapeutics. Defining the functional roles of the amphiphilic alpha-helices in medium-sized peptide hormones, and studying helix propagation from rigid, alpha-helix initiating bicyclic peptides are among the most exciting developments currently underway in this field.
Sequestration of noble gases in giant planet interiors

The Galileo probe showed that Jupiter's atmosphere is severely depleted in neon compared to protosolar values. We show via ab initio simulations of the partitioning of neon between hydrogen-helium phases that the observed depletion can be explained by the sequestration of neon into helium-rich droplets within the postulated hydrogen-helium immiscibility layer of the planets interior. We also demonstrate that this mechanism will not affect argon explaining the observed lack of depletion of this gas. This provides strong indirect evidence for hydrogen-helium immiscibility in Jupiter.
Groups where all the irreducible characters are super-monomial

AbstractIsaacs has deﬁned a character to be super monomial if every primitive characterinducing it is linear. Isaacs has conjectured that if G is an M-group with odd order,then every irreducible character is super monomial. We prove that the conjecture istrue if G is an M-group of odd order where every irreducible character is a {p}-lift forsome prime p. We say that a group where irreducible character is super monomial is asuper M-group. We use our results to ﬁnd an example of a super M-group that has asubgroup that is not a super M-group.MSC primary : 20C15Keywords : π-partial characters, lifts, M-groups, super monomial characters 1 Introduction Throughout this note, Gwill be a ﬁnite group. Following [1], we say that a character χofGis monomial if it is induced from a linear character, and a group Gis an M-group if everyirreducible character of Gis monomial. In [4], Isaacs has suggested that if Gis an M-groupof odd order and χ∈ Irr(G), then every primitive character inducing χmust be linear.For ease of exposition, we introduce some notation from [6]: the character χ∈ Irr(G)is
The porosity of additive noise sequences

Consider a binary modulo-additive noise channel with noiseless feedback. When the noise is a stationary and ergodic process Z, the capacity is 1 − H(Z) (H(·) denoting the entropy rate). It is shown analogously that when the noise is a deterministic sequence Z∞, the capacity under finite-state encoding and decoding is 1 − ρ(Z∞), where ρ(·) is Lempel and Ziv's finite-state compressibility. This quantity is termed the porosity ρ(·) of an individual noise sequence. A sequence of schemes are presented that universally achieve porosity for any noise sequence. These results may be interpreted both as a channel-coding counterpart to Ziv and Lempel's work in universal source coding, as well as an extension of the work by Lomnitz and Feder and Shayevitz and Feder on communication across modulo-additive channels.
Fast ensemble smoothing

Smoothing is essential to many oceanographic, meteorological, and hydrological applications. There are two predominant classes of smoothing problems. The first is fixed-interval smoothing, where the objective is to estimate model states within a time interval using all available observations in the interval. The second is fixed-lag smoothing, where the objective is to sequentially estimate model states over a fixed or indefinitely growing interval by restricting the influence of observations within a fixed window of time ahead of the evolving estimation time. In this paper, we use an ensemble-based approach to fixed-interval and fixed-lag smoothing, and synthesize two algorithms. The first algorithm is a fixed-interval smoother whose computation time is linear in the interval. The second algorithm is a fixed-lag smoother whose computation time is independent of the lag length. The complexity of these algorithms is presented, shown to improve upon existing implementations and verified with identical-twin experiments conducted with the Lorenz-95 system. Results suggest that ensemble methods yield efficient fixed-interval and fixed-lag smoothing solutions in the sense that the additional increment for smoothing is a small fraction of either filtering or model propagation costs in a practical ensemble application. We also show that fixed-interval smoothing can perform as fast as fixed-lag smoothing, and it may not be necessary to use a fixed-lag approximation for computational savings alone.
Optimal attitude control of a dual-spin satellite.

The fuel-optimal attitude control of a dual-spin rigid spacecraft composed of a section spinning at constant rate about an axis of symmetry and a nonspinning section carrying an experimental package is the object of this paper. Rotor-fixed reaction jets with fixed impulse are used for control. A simplified mathematical model of the spacecraft is presented. Its trajectories in the yaw-roll coordinate system following the application of impulsive control efforts are described. From here, the deduction of the fuel-optimal two-impulse control scheme (when variable impulse is available) is immediate. This yields the absolute minimum fuel requirement for a given maneuver. For the case of fixed impulses, based on a criterion obtained from the fuel-optimal two-impulse control scheme, a suboptimal control law is synthesized. An approximate graphical construction of the vehicle trajectories in the yaw-roll plane is described and illustrated with two examples. The graphs permit evaluation of the total time and fuel used for control. A detailed mechanization of the control law is described.
Exo-Dig Radical Cascades of Skipped Enediynes: Building a Naphthalene Moiety within a Polycyclic Framework

Cascade radical transformations of acyclic precursors open efficient, convenient and atom-economical access to functionalized compounds of increased structural complexity. This report describes a selective sequence of 5-exo-dig and 6-exo-dig cyclizations followed by attack at a pendant aromatic moiety and rearomatization.
Reliable far-infrared photoconductivity method to identify a variety of residual donors in epitaxial GaAs

The chemical identity of unintentional contaminants in ultra-high purity eipitaxial GaAs and related semiconductor crystals can be distinguished by submillimeter wave magneto-spectroscopy at low temperature. An improved method of identifying hydrogen-like donors such as sulfur, silicon, selenium and germanium has been developed for the purpose of correcting some mistaken identifications that have been published during the past ten years. The new method requires the development of an experimental “signature curve” for each contaminant by measuring the energy of its 1s to 2p (m=−1) transition at several values of magnetic field intensity. The energy of this transition at a given magnetic field intensity is different depending upon the nucleus to which the electron is bound in the 1s state. The validity of the improved method was tested by means of transmutation doping.
Sterols with Cyclopropane-Containing Side Chains: Synthesis and Acid Isomerization†

To test the eventual involvement of sterols with a cyclopropane containing side chain in bio-methylation processes, 24,25-methanocholest-5-en-3β-ol (5) and 24,25-methano-26-methylcholest-5-en-3β-ol (6) were synthesized. Together with the naturally occurring cyclopropane petrosterol (1), they were submitted to acid isomerization to provide chemical models for some of their potential metabolites.
Residual stress reduction by pulsed magnetic treatment

Abstract Residual stress relief by pulsed magnetic treatment is attractive since the process is carried out at room temperature and magnetic fields that are easy to produce and control can be used. The extent of residual stress reduction due to a particular pulsed magnetic treatment was determined. Initially curved strip specimens were held flat to produce a known residual stress and then subjected to a pulsed magnetic treatment. Curvature measurements and microhardness measurements before and after treatment and a mechanical model relating stress and indentation size were used to specify the change in residual stress due to pulsed magnetic treatment. Changes of stress near the surface of the specimens due to treatment were obtained. Reductions of residual stress of 4–7% were obtained for the particular pulsed magnetic treatment used on lower initial stress level specimens. For a higher initial stress level stress reductions of 8–13% were measured.
Quasars and Ultraluminous Infrared Galaxies: At the Limit?

We have detected the host galaxies of 16 nearby, radio-quiet quasars using images obtained with the Near-Infrared Camera and MultiObject Spectrometer. We confirm that these luminous quasars tend to live in luminous, early-type host galaxies, and we use the host-galaxy magnitudes to refine the luminosity/host-mass limit inferred from ground-based studies. If quasars obey the relation M_(blackhole)/M_(spheroid) ~ 0.006 found for massive dark objects in nonactive galaxies, then our analysis implies that they radiate at up to ~20% of the Eddington rate. An analogous analysis for ultraluminous infrared galaxies shows them to accrete at up to similar Eddington fractions, consistent with the hypothesis that some of them are powered by embedded quasars.
Quantum protectorates in the cuprate superconductors

Following the identification of the pairing state, the major challenge in understanding the cuprate superconductors has been determining the evolution with doping and temperature of their anomalous normal state behavior. Key to this understanding is the experimentally determined magnetic phase diagram for the cuprates, which provides information on the protected magnetic properties of the normal state, generic behavior that is reliably the same one system to the next, regardless of details. I discuss the constraints this places on candidate quantum protectorates, and the status of microscopic model calculations for a protectorate consistent with these constraints, the nearly antiferromagnetic Fermi liquid.
Self-gravitating gas flow in barred spiral galaxies

A series of two-dimensional numerical experiments is performed in order to test the response of an isothermal, self-gravitating gas disk to a uniformly rotating, barlike gravitational potential. The barlike potential is an equilibrium stellar model from the n-body calculations of Miller and Smith (1979). In the bar-dominated, central regions of the disk, a gas bar whose phase depends primarily on the location of principal resonances in the disk is formed. This response can be understood in terms of orbit-crowding effects. In the gas-dominated outer regions of the disk, two-armed trailing spiral waves are formed. The local pitch angle of these waves increases with increasing fractional gas mass. These self-gravitating gas waves are not self-sustaining. They are driven from the ends of equilibrium stellar bars, and their phase does not depend on the location of resonances in the disk. The relevance of these self-gravitating waves to observations and models of barred spiral galaxies is discussed. It is concluded that these waves and their associated ringlike structures may be consistent with the morphological distribution of gas features in barred spiral galaxies.
Palladium Thin Films Grown by CVD from (1,1,1,5,5,5‐Hexafluoro‐2,4‐pentanedionato) Palladium(II)

The precursor (1,1,1,5,5,5-hexafluoro-2,4-pentanedionato) palladium(II) [Pd(hfac)2] was used to deposit high-purity, polycrystalline palladium films under low-pressure CVD conditions at high growth rates (1000–4000 A/min) over a substrate temperature range of 80–200°C in the presence of H2. Mixing of the precursor and H2 streams near the substrate was required to avoid reactions of the precursor with H2 at locations other than the substrate surface. Auger electron spectroscopy (AES) showed that the films were impurity free when sufficient H2 was used. Resistivity values of 20 μΩcm were obtained at the higher deposition temperatures (∼200 °C) while high values of 50 μΩ cm were observed at the lower deposition temperatures (∼ 90 °C). The deposition rate was feed-rate limited even at the lowest deposition temperatures and highest precursor delivery rates, suggesting that even higher deposition rates could be obtained with higher feed rates. A high precursor conversion of 50–60 % was observed. The high surface reaction probability of Pd(hfac)2 in the presence of H2 was reflected qualitatively by trench fill studies which showed a greater film thickness on the top of sub-micrometer trenches than in the bottom.
Effects of sodium chloride, phytate and tannin on in vitro proteolysis of phaseolin

Abstract Native phaseolins isolated from the Great Northern bean (Phaseolus vulgaris L.) and the tepary bean (Phaseolus acutifolius L.) were resistant to TPCK-trypsin, TLCK-chymotrypsin, and pepsin proteolysis in vitro. Sodium chloride (1 M) significantly decreased the initial rate of in vitro. proteolysis of both phaseolins. However, moist heat (30 min, 100 °C) denaturation of the phaseolins facilitated complete in vitro. proteolysis by all the proteinases tested. Added phytate (phaseolin:phytate ratios 10:1, 5:1, and 1:1; w w ) decreased the initial in vitro. proteolysis rates of the Great Northern bean phaseolin (GNP) by chymotrypsin and pepsin (but not trypsin) and that of the tepary phaseolin (TP) by pepsin (TP:phytate ratios 5:1 and 1:1, w w ). Tannin addition decreased the initial rate of in vitro. proteolysis of both phaseolins digested with chymotrypsin (phaseolin:-tannin ratios 100:1 and 50:1, w w ) and TP digested with pepsin (TP:tannin ratio of 10:1, w w ). This inhibitory effect of added phytate and tannin was lower than the inhibitory effect of 1 M sodium chloride. Since moist heat denaturation was able to overcome the inhibitory effect of sodium chloride, the inhibitory effects of added phytate and tannin should not impede in vitro. phaseolin proteolysis.
Outcomes of Infants Undergoing Superior Cavopulmonary Connection in the Presence of Ventricular Dysfunction

Outcomes in patients with ventricular dysfunction undergoing superior cavopulmonary connection (SCPC) are not well known. We reviewed records of patients undergoing SCPC at our center from December 2005 to October 2009 and studied those whose pre-SCPC echocardiograms demonstrated at least moderate systemic ventricular dysfunction. Of the 213 patients undergoing SCPC, 19 (9%) met inclusion criteria. Diagnoses were hypoplastic left heart syndrome (n = 18) and rightward unbalanced atrioventricular canal with pulmonary stenosis (n = 1). In those surviving >2 months after SCPC, ventricular function was assessed by echocardiography 4.9 (range 3.5 to 9.7) months after SCPC and was improved in ten of 17 (59%), unchanged in six of 17 (35%), and worsened in one of 17 (16%) patients. After SCPC, three patients died, and one underwent heart transplant 21.9 months after SCPC. Transplant-free survival was attained by 15 of 19 (79%) patients during follow-up of 33.0 months (range 10.8 to 51.4). Fontan completion was performed on six survivors on reaching an appropriate age. Ventricular dysfunction before SCPC is not uncommon and occurs primarily in patients with a morphologic right ventricle. Ventricular performance improves in the majority of patients after SCPC, and midterm outcomes are comparable with previous reports, suggesting that these patients remain candidates for staged palliation.
An overview of combustion noise

Combustion noise was discussed as early as 1802 in a technical note on singing flames. Occasional papers followed this early work up to about 1950, when jet propulsion spurred interest. Since then there has been a continual broadening of the areas of interest: Now the phenomena related to combustion noise are considered in a host of specific uses of combustion. This review is based on the authors' observations of nonpropulsive combustion in the residential, commercial, and industrial fields, although it is realized that there are many parallels to specific propulsive applications. Three specific areas of combustion noise are discussed in some detail, namely, combustion roar, combustion-driven oscillations, and pulse combustion. Combustion roar, in the absence of acoustic distortion effects, is characterized by a smooth noise spectrum related to the reacting chemistry of the flame and the turbulence level of the combustion region. Combustion-driven oscillations are characterized by a discrete frequency and a feedback cycle to maintain the oscillation. Pulse combustion is the positive application of combustiondriven oscillations. In addition, some other combustion noise phenomena are discussed, such as the interaction with vortex shedding and the combustion amplification of flow phenomena.
Relative Hyperbolicity and Artin Groups

Let G=l a1,l , a n | a i a j a i l = a_ja_ia_j,l ,i>jr be an Artin group and let m ij =m ji be the length of each of the sides of the defining relation involving a i and a j . We show if all m_ij g 7 then G is relatively hyperbolic in the sense of Farb with respect to the collection of its two-generator subgroups 〈a i , a j 〉for which m_ij >i.
Comparing Suzaku and XMM-Newton Observations of the Soft X-Ray Background: Evidence for Solar Wind Charge Exchange Emission

We present an analysis of a pair of Suzaku spectra of the soft X-ray background (SXRB), obtained from pointings on and off a nearby shadowing filament in the southern Galactic hemisphere. Because of the different Galactic column densities in the two pointing directions, the observed emission from the Galactic halo has a different shape in the two spectra. We make use of this difference when modeling the spectra to separate the absorbed halo emission from the unabsorbed foreground emission from the Local Bubble (LB). The temperatures and emission measures we obtain are significantly different from those determined from an earlier analysis of XMM-Newton spectra from the same pointing directions. We attribute this difference to the presence of previously unrecognized solar wind charge exchange (SWCX) contamination in the XMM-Newton spectra, possibly due to a localized enhancement in the solar wind moving across the line of sight. Contemporaneous solar wind data from ACE show nothing unusual during the course of the XMM-Newton observations. Our results therefore suggest that simply examining contemporaneous solar wind data might be inadequate for determining if a spectrum of the SXRB is contaminated by SWCX emission. If our Suzaku spectra are not badly contaminated by SWCX emission, our best-fitting LB model gives a temperature of -->log (TLB/K) = 5.98?0.04+0.03 and a pressure of -->pLB/k = 13,100-16,100 cm?3 K. These values are lower than those obtained from other recent observations of the LB, suggesting the LB may not be isothermal and may not be in pressure equilibrium. Our halo modeling, meanwhile, suggests that neon may be enhanced relative to oxygen and iron, possibly because oxygen and iron are partly in dust.
A successful acid promoted asymmetric pictet-spengler reaction of Na-BOC protected tryptophans. Effect of the BOC group on reactivity and stereoselectivity

Abstract N a -BOC protected tryptophans 1 and 2 successfully undergo the Pictet-Spengler cyclization with a series of aldehydes in the presence of an acid catalyst ( p -TSA) to furnish a mixture of trans and cis 1,2,3,4-tetrahydro-β-carbolines (3 and 4). During removal of the BOC function with TFA, the mixture of trans (3) and cis (4) isomers was enantiospecifically converted into the trans N a -H 1,2,3,4-teaahydro-β-carboline 5, a key intermediate for the construction of N a ,-H substituted sarpagine alkaloids.
The microwave background temperature at 2.64 and 1.32 millimeters

Very high signal-to-noise observations of the 3874 A band of interstellar CN toward Zeta Oph are presented. Measurements are conducted of equivalent widths for the R(0), R(1), R(2), and P(1) lines which agree with previous photoelectric, but not photographic, findings. Corrected for saturation, these strengths yield excitation temperatures of 2.73 + or - 0.04 K and 2.8 + or - 0.3 K for the J = 0 to 1 and J = 1 to 2 rotational transitions at 2.64 mm and 1.32 mm respectively. Since the cosmic microwave background radiation (CMB) is primarily responsible for populating the excited rotational levels of interstellar CN toward Zeta Oph, these values are actually upper limits on the CMB brightness temperature at 2.64 mm and 1.32 mm. The results are consistent with a 2.7 K blackbody spectrum for the CMB and do not support the spectral deviations observed near these wavelengths by Woody and Richards.
t Hooft conditions in supersymmetric dual theories

Abstract The matching of global anomalies of a supersymmetric gauge theory and its dual is seen to follow from similarities in their classical chiral rings. These similarities provide a formula for the dimension of the dual gauge group. As examples we derive 't Hooft consistency conditions for the duals of supersymmetric QCD and SU ( N ) theories with matter in the adjoint, and obtain the dimension of the dual groups.
Winner-take-all selection in a neural system with delayed feedback

We consider the effects of temporal delay in a neural feedback system with excitation and inhibition. The topology of our model system reflects the anatomy of the avian isthmic circuitry, a feedback structure found in all classes of vertebrates. We show that the system is capable of performing a ‘winner-take-all’ selection rule for certain combinations of excitatory and inhibitory feedback. In particular, we show that when the time delays are sufficiently large a system with local inhibition and global excitation can function as a ‘winner-take-all’ network and exhibit oscillatory dynamics. We demonstrate how the origin of the oscillations can be attributed to the finite delays through a linear stability analysis.
Water at a hydrophilic solid surface probed by ab-initio molecular dynamics: inhomogeneous thin layers of dense fluid

We present a microscopic model of the interface between liquid water and a hydrophilic, solid surface, as obtained from ab initio molecular dynamics simulations. In particular, we focused on the (100) surface of cubic SiC, a leading semiconductor candidate for biocompatible devices. Our results show that in the liquid in contact with the clean substrate, molecular dissociation occurs in a manner unexpectedly similar to that observed in the gas phase. After full hydroxylation takes place, the formation of a thin (∼3 A) interfacial layer is observed, which has higher density than bulk water and forms stable hydrogen bonds with the substrate. The presence of this thin layer points at rather weak effects on the structural properties of water induced by a one-dimensional confinement between ∼1.3 nm hydrophilic substrates. In addition, our results show that the liquid does not uniformly wet the surface, but molecules preferably bind along directions parallel to the Si dimer rows.
Contemporary approaches to the identification of athletes at risk for sudden cardiac death

Purpose of reviewThe appropriate screening strategy to prevent sudden cardiac death (SCD) in athletes remains a challenging and a highly debated issue. The purpose of this review is to examine the added value and controversies of including a 12-lead electrocardiogram (ECG) in addition to a comprehen
Diffusion and thermal escape of H2 from Titan's atmosphere: Monte Carlo simulations

The Direct Simulation Monte Carlo (DSMC) technique is used here to describe the transition region in Titan’s atmosphere where the gas flow goes from being collisional to collisionless. We expand on our previous study (Tucker, O.J., Johnson, R.E. [2009]. Planet. Space Sci. 57, 1889–1894) by including H2 in addition to CH4 and N2. We again find that thermal escape of CH4 is Jeans-like, contrary to what has been suggested by some fluid/continuum models. However, we also show that the temperature of molecular hydrogen separates from the background gas well below the exobase, and its escape cools the background gas. This results in a non-isothermal CH4 density profile without requiring an upward CH4 flux and, therefore, fits using the diffusion equation can overestimate the escape flux. These simulations also reproduce the Cassini H2 density versus altitude data averaged over flybys for which Titan is orbiting in Saturn’s plasma sheet, but with a somewhat different escape rate than suggested by the diffusion equation. However, for flybys for which Titan is not in Saturn’s plasma sheet our simulations result in H2 densities that diffusively separate from the N2 densities at lower altitudes than typically indicated by the Cassini data. By tracking ballistic transport in the H2 corona we show that a global, as well as temporal description of the exobase region is required.
Therapeutic Applications of Ghrelin Agonists in the Treatment of Gastroparesis

There remains an unmet need for effective pharmacologic treatments for gastroparesis. Ghrelin is the endogenous ligand for the growth hormone secretagogue receptor and has been shown to regulate energy homeostasis and exert prokinetic effects on gastrointestinal motility. In recent years, several ghrelin receptor agonists have been studied in clinical trials of patients with diabetic gastroparesis. The intravenous macrocyclic peptidomimetic, TZP-101, initially suggested improvement in gastroparesis symptoms with intravenous administration when compared to placebo. However, in subsequent studies of oral preparations, TZP-102 failed to confirm these results. Another ghrelin receptor agonist, RM-131, was recently shown to significantly accelerate gastric emptying (GE) in patients with type 1 and type 2 diabetes and delayed GE. RM-131 reduced total Gastroparesis Cardinal Symptom Index-Daily Diary (GCSI-DD) and composite scores among type 1 diabetics. Continued development of ghrelin agonists should be explored in attempts to expand therapeutic options for the treatment of gastroparesis.
The Structure of Chinese Urban Land Prices: Estimates from Benchmark Land Price Data

Taking the recent benchmark land prices published by the Chinese city governments, the paper estimates commercial and residential land price curves of Chinese cities using cross-sectional data, controlling for urban population size and income level. The urban land leasing price–distance relationship is estimated based on the argument that monocentric urban structure is representative for Chinese cities. Both population size and income level are found to positively affect urban land price and price–distance gradients. Commercial land prices are higher than residential land prices except in suburbs or outer central urban areas, where the land prices of different uses converge. In most situations, commercial use price gradients are larger than those of residential use.
Jet Acceleration by Tangled Magnetic Fields

We explore the possibility that extragalactic radio jets might be accelerated by highly disorganized magnetic fields that are strong enough to dominate the dynamics until the terminal Lorentz factor is reached. Following the twin-exhaust model by Blandford & Rees, the collimation under this scenario is provided by the stratified thermal pressure from an external medium. The acceleration efficiency then depends on the pressure gradient of that medium. In order for this mechanism to work there must be continuous tangling of the magnetic field, changing the magnetic equation of state away from pure flux freezing (otherwise, conversion of Poynting flux to kinetic energy flux is suppressed). This is a complementary approach to models in which the plasma is accelerated by large-scale ordered fields. We include a simple prescription for magnetic dissipation, which leads to trade-offs among conversion of magnetic energy into bulk kinetic energy, random particle energy, and radiation. We present analytic dynamical solutions of such jets, assess the effects of radiation drag, and comment on observational issues, such as the predicted polarization and synchrotron brightness. Finally, we try to make the connection to observed radio galaxies and γ-ray bursts.
Internal mammary node status: a major prognosticator in axillary node-negative breast cancer

Background: The internal mammary lymph nodes (IMN) have received little attention in recent years, yet are a well-documented site of metastasis and a major prognostic factor in early-stage breast cancer. Methods/Results: Ten-year follow-up of the final 195 patients treated by extended radical mastectomy (ERM) in this practice (selected largely on the basis of medial tumor location, and comprising 15% of all patients treated from 1965 to 1978) found IMN + in 24% of all cases: 36% of AX + versus 18% of AX -patients (p=0.0023). In a multivariate analysis, the disease-free survival impact of IMN + (p=0.004) was second only to axillary node involvement (p<0.0005), and surpassed tumor size (p=0.077). IMN + was equally frequent for tumors less than, or greater than, 2 cm (24%), and was not significantly related to patient age. Among AX - patients, there was a twofold greater risk of recurrence or death at 10 years for IMN + than for IMN -. Among T1N0 patients, 19.6% were IMN +. Conclusions: Failure to consider IMN status in the steadily enlarging cohort of T1N0 breast cancers may result in the undertreatment of a significant proportion of stage I patients. Systemic adjuvant therapy should be considered for T1N0 patients with central or medial tumors.
Strategic climate policy with offsets and incomplete abatement: Carbon taxes versus cap-and-trade

Abstract This paper provides a first analysis of a “policy bloc” of fossil fuel importers which implements an optimal climate policy, faces a (non-policy) fringe of other fuel importers, and an exporter bloc, and purchases offset from the fringe. We compare a carbon tax and a cap-and-trade scheme for the policy bloc, in either case accompanied by an efficient offset mechanism for reducing emissions in the fringe. The policy bloc is shown to prefer a tax over a cap, since only a tax reduces the fuel export price and by more when the policy bloc is larger. Offsets are also more favorable to the policy bloc under a tax than under a cap. The optimal offset price under a carbon tax is below the tax rate, while under a cap and free quota trading the offset price must equal the quota price. The domestic carbon and offset prices are both higher under a tax than under a cap when the policy bloc is small. When the policy bloc is larger, the offset price can be higher under a cap. Fringe countries gain by mitigation in the policy bloc, more under a carbon tax since the fuel import price is lower.
Representation and character theory in 2-categories

We develop a (2-)categorical generalization of the theory of group representations and characters. We categorify the concept of the trace of a linear transformation, associating to any endofunctor of any small category a set called its categorical trace. In a linear situation, the categorical trace is a vector space and we associate to any two commuting self-equivalences a number called their joint trace. For a group acting on a linear category we define an analog of the character which is the function on commuting pairs of group elements given by the joint traces of the corresponding functors. We call this function the 2-character of . Such functions of commuting pairs (and more generally, n-tuples) appear in the work of Hopkins, Kuhn and Ravenel [Michael J. Hopkins, Nicholas J. Kuhn, Douglas C. Ravenel, Generalized group characters and complex oriented cohomology theories, J. Amer. Math. Soc. 13 (3) (2000) 553�594 (electronic)] on equivariant Morava E-theories. We define the concept of induced categorical representation and show that the corresponding 2-character is given by the same formula as was obtained in [Michael J. Hopkins, Nicholas J. Kuhn, Douglas C. Ravenel, Generalized group characters and complex oriented cohomology theories, J. Amer. Math. Soc. 13 (3) (2000) 553�594 (electronic)] for the transfer map in the second equivariant Morava E-theory
Sociomaterial bricolage: The creation of location-spanning work practices by global software developers

Context: Studies on global software development have documented severe coordination and communication problems among coworkers due to geographic dispersion and consequent dependency on technology. These problems are exacerbated by increase in the complexity of work undertaken by global teams. However, despite these problems, global software development is on the rise and firms are adopting global practices across the board, raising the question: What does successful global software development look like and what can we learn from its practitioners? Objective: This study draws on practice-based studies of work to examine successful work practices of global software developers. The primary aim of this study was to understand how workers develop practices that allow them to function effectively across geographically dispersed locations. Method: An ethnographically-informed field study was conducted with data collection at two international locations of a firm. Interview, observation and archival data were collected. A total of 42 interviews and 3weeks of observations were conducted. Results: Teams spread across different locations around the world developed work practices through sociomaterial bricolage. Two facets of technology use were necessary for the creation of these practices: multiplicity of media and relational personalization at dyadic and team levels. New practices were triggered by the need to achieve a work-life balance, which was disturbed by global development. Reflecting on my role as a researcher, I underscore the importance of understanding researchers' own frames of reference and using research practices that mirror informants' work practices. Conclusion: Software developers on global teams face unique challenges which necessitate a shift in their work practices. Successful teams are able to create practices that span locations while still being tied to location based practices. Inventive use of material and social resources is central to the creation of these practices.
THERMODYNAMICS OF THE CONVERSION OF AQUEOUS GLUCOSE TO FRUCTOSE

The thermodynamics of the conversion of aqueous glucose to fructose has been investigated using both heat conduction microcalorimetry and high pressure liquid chromatography (HPLC). The reaction was carried out in both aqueous Tris/HCl buffer and in aqueous phosphate buffer in the pH range 7–8 using the enzyme glucose isomerase and the cofactors CoCl2 and MgSO4. The temperature range over which this reaction was investigated was 298.15–358.15 K. We have found that the enthalpy of reaction is independent of pH over the range investigated. A combined analysis of both the HPLC and microcalorimetric data leads to the following results at 298 15 K:ΔG° = 349 ± 53 J mol-1, ΔH° = 2.78 ± 0.20 kJ mol-1, and ΔC p ° = 76 ± 30 J mol-1 K-1. The stated uncertainties are based upon an analysis of both the random and systematic errors inherent in the measurements. Comparisons are made with literature data. The percent conversion of glucose to fructose has been calculated for the temperature range 300–373.15 K.
X-Ray Pulsations in the Supersoft X-Ray Binary CAL 83

Chandra and XMM-Newton X-ray data reveal that the supersoft X-ray binary CAL 83 exhibits 38.4 minute pulsations at some epochs. These X-ray variations are similar to those found in some novae and are likely to be caused by nonradial pulsations of the white dwarf. This is the first detection of pulsations in a classical supersoft X-ray binary.
Holography and cosmological singularities

Certain null singularities in ten dimensional supergravity have natural holographic duals in terms of Matrix Theory and generalizations of the AdS/CFT correspondence. In many situations the holographic duals appear to be well defined in regions where the supergravity develops singularities. We describe some recent progress in this area.
Uncertainty, irreversibility, and investment in second-generation biofuels

The present study quantifies the importance of price risk and irreversibility for investment in a corn stover-based cellulosic biofuel plant. Using a real-option model, we recover prices of gasoline that would trigger entry into the market and compare it to breakeven price. Our analysis shows that the price premium (above breakeven) required by investors to enter the market due to risk is substantial. Managerial flexibility (embedded in the option of mothballing and reactivating the plant) does not sensibly reduce the entry premium. Results also show that price volatility may greatly reduce plants’ responsiveness to gasoline prices and decrease supply elasticity. In combination, results suggest that (1) policies supporting second-generation biofuels may have fell short of their targets because of their failure to alleviate price uncertainty and (2) the use of price-based instruments such as reverse auctions, either in isolation or in combination with mandates, may be warranted.
Status Report—Advanced Heat Exchanger Technology for a CCGT Power Generation System

This report gives laboratory and field test results of a specially designed heat exchanger for coal-fired power plants. The system incorporates an atmospheric fluidized bed and combustion system for pulverized coal. The heat exchanger was made from both metallic and ceramic materials.
Performing remote operations efficiently on a local computer network

A communication model is described that can serve as a basis for a highly efficient communication subsystem for local networks. The model contains a taxonomy of communication instructions that can be implemented efficiently and can be a good basis for interprocessor communication. These communication instructions, called remote references, cause an operation to be performed by a remote process and, optionally, cause a value to be returned. This paper also presents implementation considerations for a communication system based upon the model and describes an experimental communication subsystem that provides one class of remote references. These remote references take about 150 microseconds or 50 average instruction times to perform on Xerox Alto computers connected by a 2.94 megabit Ethernet.
Control of quantum phenomena: past, present and future

Quantum control is concerned with active manipulation of physical and chemical processes on the atomic and molecular scale. This work presents a perspective of progress in the field of control over quantum phenomena, tracing the evolution of theoretical concepts and experimental methods from early developments to the most recent advances. Among numerous theoretical insights and technological improvements that produced the present state-of- the-art in quantum control, there have been several breakthroughs of foremost importance. On the technology side, the current experimental successes would be impossible without the development of intense femtosecond laser sources and pulse shapers. On the theory side, the two most critical insights were (i) realizing that ultrafast atomic and molecular dynamics can be controlled via manipulation of quantum interferences and (ii) understanding that optimally shaped ultrafast laser pulses are the most effective means for producing the desired quantum interference patterns in the controlled system. Finally, these theoretical and experimental advances were brought together by the crucial concept of adaptive feedback control (AFC), which is a laboratory procedure employing measurement-driven, closed-loop optimization to identify the best shapes of femtosecond laser control pulses for steering quantum dynamics towards the desired objective. Optimization in AFC experiments is guided by a learning algorithm, with stochastic methods proving to be especially effective. AFC of quantum phenomena has found numerous applications in many areas of the physical and chemical sciences, and this paper reviews the extensive experiments. Other subjects discussed include quantum optimal control theory, quantum control landscapes, the role of theoretical control
Proceedings of the Future of Emergency Medicine Research Conference, Part I: Executive Summary☆☆☆★★★♢

The five articles presented in this section were written by representatives of the emergency medicine research community during the "Future of Emergency Medicine Research Conference," March 6 and 7, 1997, in Washington DC. Each presentation was balanced with commentary by two conference participants from outside emergency medicine. The discussion of each presentation was opened to scrutiny and analysis by all the conference participants. The participants included representatives from governmental agencies and other clinical specialties with the experience and understanding of specialty research enhancement. The objectives and recommendations in this final summary are the result of considerable insight and discussion from all participants. The specialty of emergency medicine owes a special thanks to those from outside the specialty who volunteered their time and effort to share their wisdom with us. Although the 35 participants represent many points of view, not all potential viewpoints were included. Hence, there may be other actions that need to be taken by organizations and individuals to advance emergency medicine research. It is now the responsibility of each individual emergency physician to carefully consider his or her own role and commitment in the process of advancing emergency medicine research. Our collective will as academic departments and the organized emergency medicine community must reaffirm our belief in the importance of emergency medicine research. Individually and collectively, we will need to dedicate the necessary resources to implement the strategies suggested for enhancing emergency medicine research training extramural funding, national organization support, multicenter research, and new research outcomes.
Quantitative analysis of watershed geomorphology

Quantitative geomorphic methods developed within the past few years provide means of measuring size and form properties of drainage basins. Two general classes of descriptive numbers are (1) linear scale measurements, whereby geometrically analogous units of topography can be compared as to size; and (2) dimensionless numbers, usually angles or ratios of length measures, whereby the shapes of analogous units can be compared irrespective of scale. Linear scale measurements include length of stream channels of given order, drainage density, constant of channel maintenance, basin perimeter, and relief. Surface and crosssectional areas of basins are length products. If two drainage basins are geometrically similar, all corresponding length dimensions will be in a fixed ratio. Dimensionless properties include stream order numbers, stream length and bifurcation ratios, junction angles, maximum valley-side slopes, mean slopes of watershed surfaces, channel gradients, relief ratios, and hypsometric curve properties and integrals. If geometrical similarity exists in two drainage basins, all corresponding dimensionless numbers will be identical, even though a vast size difference may exist. Dimensionless properties can be correlated with hydrologic and sediment-yield data stated as mass or volume rates of flow per unit area, independent of total area of watershed.
Adaptive, High Bandwidth Control of a Hydraulic Actuator

Hydraulic servovalve controlled systems contain many time-varying dynamic characteristics that are difficult to model. Controllers for such systems must either adapt to these changing parameters or be robust enough to handle the parameter variations. In order to achieve the highest possible bandwidth, an adaptive controller is developed for the system that uses full-state feedback for simultaneous parameter identification and tracking control. This controller takes into account the hydraulic fluid compressibility with an on-line identification scheme. Experimental results demonstrate a four fold improvement in bandwidth as compared to a conventional fixed gain proportional controller.
Healthcare strategic management and the resource based view

Purpose – The purpose of this paper is to examine how two large health systems formulate and implement strategy with a specific focus on differences and similarities in the nature of strategic initiatives across systems. The aim is to gain a better understanding of the role of resource dependency theory (RDT) and resource based view (RBV) in healthcare strategic management. Design/methodology/approach – A comparative case study design is used to describe, categorize and compare strategic change initiatives within a children's health and a multi-hospital system located in two competitive metropolitan markets. A total of 61 in-person semi-structured interviews with healthcare administrators were conducted during 2009. Summary statistics and qualitative content analysis were employed to examine strategic initiatives. Findings – The two health systems have as their top initiatives very similar pursuits, thus indicating that both utilize an externally oriented RDT method of strategy formulation. The relevance ...
Circumscription—a form of non-monotonic reasoning

Humans and intelligent computer programs must often jump to the conclusion that the objects they can determine to have certain properties or relations are the only objects that do. Circumscription formalizes such conjectural reasoning.