cssi/SciSciGPT-SciSciNet huggingface dataset:
An impossibility result for truthful combinatorial auctions with submodular valuations

We show that every universally truthful randomized mechanism for combinatorial auctions with submodular valuations that provides an approximation ratio of m1/ 2 -e must use exponentially many value queries, where m is the number of items. In contrast, ignoring incentives there exist constant ratio approximation algorithms for this problem. Our approach is based on a novel direct hardness technique that completely skips the notoriously hard step of characterizing truthful mechanisms. The characterization step was the main obstacle for proving impossibility results in algorithmic mechanism design so far. We demonstrate two additional applications of our new technique: (1) an impossibility result for universally-truthful polynomial time flexible combinatorial public projects and (2) an impossibility result for truthful-in-expectation mechanisms for exact combinatorial public projects. The latter is the first result that bounds the power of polynomial-time truthful in expectation mechanisms in any setting.
Spitzer Transit and Secondary Eclipse Photometry of GJ 436b

We report the results of infrared (8 μm) transit and secondary eclipse photometry of the hot Neptune exoplanet, GJ 436b using Spitzer. The nearly photon-limited precision of these data allows us to measure an improved radius for the planet and to detect the secondary eclipse. The transit (centered at HJD = 2454280.78149 ± 0.00016) shows the flat-bottomed shape typical of infrared transits, and it precisely defines the planet-to-star radius ratio (0.0839 ± 0.0005), independent of the stellar properties. However, we obtain the planetary radius, as well as the stellar mass and radius, by fitting to the transit curve simultaneously with an empirical mass-radius relation for M dwarfs (M = R). We find R* = M* = 0.47 ± 0.02 in solar units, and Rp = 27,600 ± 1170 km (4.33 ± 0.18 R⊕). This radius significantly exceeds the radius of a naked ocean planet and requires a gaseous hydrogen-helium envelope. The secondary eclipse occurs at phase 0.587 ± 0.005, proving a significant orbital eccentricity (e = 0.150 ± 0.012). The amplitude of the eclipse [(5.7 ± 0.8) × 10-4] indicates a brightness temperature for the planet of T = 712 ± 36 K. If this is indicative of the planet's physical temperature, it suggests the occurrence of tidal heating in the planet. An uncharacterized second planet likely provides ongoing gravitational perturbations that maintain GJ 436b's orbit eccentricity over long timescales.
Chemoselectivity: The Mother of Invention in Total Synthesis

The true creator is necessity, who is the mother of our invention. — Plato IUPAC defines chemoselectivity as “the preferential reaction of a chemical reagent with one of two or more different functional groups”, a definition that describes in rather understated terms the single greatest obstacle to complex molecule synthesis. Indeed, efforts to synthesize natural products often become case studies in the art and science of chemoselective control, a skill that nature has practiced deftly for billions of years but man has yet to master. Confrontation of one or perhaps a collection of functional groups that are either promiscuously reactive or stubbornly inert has the potential to unravel an entire strategic design. One could argue that the degree to which chemists can control chemoselectivity pales in comparison to the state of the art in stereocontrol. In this Account, we hope to illustrate how the combination of necessity and tenacity leads to the invention of chemoselective chemistry for the construction...
Recurrent primary biliary cirrhosis, primary sclerosing cholangitis, and autoimmune hepatitis after transplantation

1. Recurrent primary biliary cirrhosis (PBC) after transplantation is controversial, but most studies support disease recurrence within the graft. 2. Granulomatous destructive cholangitis should be present, and exclusion of acute and chronic rejection, graft-versus-host disease, biliary obstruction, viral hepatitis, and drug effects is mandatory before making a diagnosis of recurrent PBC. 3. Recurrent primary sclerosing cholangitis (PSC) after transplantation is difficult to diagnose because of the lack of a diagnostic gold standard. 4. Well-defined cholangiographic and histological criteria should be present, and exclusion of preservation injury, blood group type incompatibility between donor and recipient, chronic rejection, hepatic arterial occlusion, and viral infection is mandatory before making a diagnosis of recurrent PSC. 5. Most studies support recurrent autoimmune hepatitis (AIH) after transplantation based on clinical, biochemical, serological, and histological criteria. Exclusion of rejection, viral infection, drug effects, and biliary obstruction is mandatory before making a diagnosis of recurrent AIH. 6. Intermediate-term patient and graft survival are excellent for patients with recurrent autoimmune liver diseases within the transplanted liver, but additional studies are required to address the impact of disease recurrence on long-term patient and graft survival.
Existence, Stability and Bifurcation of Random Complete and Periodic Solutions of Stochastic Parabolic Equations

Abstract In this paper, we study the existence, stability and bifurcation of random complete and periodic solutions for stochastic parabolic equations with multiplicative noise. We first prove the existence and uniqueness of tempered random attractors for the stochastic equations and characterize the structures of the attractors by random complete solutions. We then examine the existence and stability of random complete quasi-solutions and establish the relations of these solutions and the structures of tempered attractors. When the stochastic equations are incorporated with periodic forcing, we obtain the existence and stability of random periodic solutions. For the stochastic Chafee–Infante equation, we further establish the multiplicity and stochastic bifurcation of complete and periodic solutions.
Design and Verification of a Cloud Field Optical Simulator

A concept and an apparatus designed to investigate the reflected and transmitted distributions of light from optically thick clouds is presented. The Cloud Field Optical Simulator (CFOS) is a laboratory device which utilizes an array of incandescent lamps as a source, simulated clouds made from cotton or styrofoam as targets, and an array of silicon photodiodes as detectors. The device allows virtually any source-target-detector geometry to be examined. Similitude between real clouds and their CFOS cotton or styrofoam counterparts is established by relying on a linear relationship between optical depth and the ratio of reflected to transmitted light for a semiinfinite layer. Comparisons of principal plane radiances observed by the CFOS with Monte Carlo computations for a water cloud at 0.7 micron show excellent agreement. Initial applications of the CFOS are discussed.
SPECTRAL EVOLUTION OF THE EXTRAORDINARY TYPE IIn SUPERNOVA 2006gy

We present a detailed analysis of the extremely luminous and long-lasting Type IIn supernova (SN) 2006gy using spectra obtained between days 36 and 237 after explosion. We derive the temporal evolution of the effective temperature, radius, blast-wave and SN-ejecta expansion speeds, and bolometric luminosity, as well as the progenitor wind density and total swept-up mass overtaken by the shock. SN 2006gy can be interpreted in the context of shock interaction with a dense circumstellar medium (CSM), but with quite extreme values for the CSM mass of ~20 M ☉ and SN explosion kinetic energy of at least 5 × 1051 erg. A key difference between SN 2006gy and other SNe IIn is that, owing to its large amount of swept-up mass, the interaction region remained opaque much longer. At early times, Hα emission-line widths suggest that the photosphere is ahead of the shock, and photons diffuse out through the opaque CSM shell. The pivotal transition to optically thin emission occurs around day 110, when we start to see a decrease in the blackbody radius R BB and strengthening tracers of the post-shock shell. From the evolution of pre-shock velocities, we deduce that the CSM was ejected by the progenitor star in a 1049 erg precursor event ~8 yr before the explosion. The large CSM mass definitively rules out models involving stars with initial masses of 10 M ☉. If the pre-SN mass budget also includes the likely SN ejecta mass of 10-20 M ☉ and the distant >10 M ☉ shell inferred from a light echo, then even massive M ZAMS = 30-40 M ☉ progenitor stars are inadequate. At roughly solar metallicity, substantial mass loss probably occurred during the star's life, so SN 2006gy's progenitor is more consistent with sequential giant luminous blue variable eruptions or pulsational pair-instability ejections in extremely massive stars with initial masses above 100 M ☉. This requires significant revision to current paradigms of massive-star evolution.
Exotic Quarkonium Spectroscopy: X(3872), Z_b(10610), and Z_b(10650) in Non-Relativistic Effective Theory

This talk summarizes recent developments in quarkonium spectroscopy. I comment on the relation between the Zb(10610) and Zb(10650) and recently observed Zc(3900) and Zc(4025) states. Then I discuss a number of calculations using non-relativistic effective field theory for the X(3872), Zb(10610), and Zb(10650), under the assumption that these are shallow molecular bound states of charm or bottom mesons.
Comparison of AMIE-modeled and Sondrestrom-measured joule heating: A study in model resolution and electric field-conductivity correlation

[1] Joule heating by high-latitude ionospheric electric fields is thought to be underestimated by models, and it has been conjectured that the source of the underestimation is “electric field variability,” which is often defined as electric field structure below the resolution of the model. We investigate this and related issues by (1) comparing the Joule heating measured by the Sondrestrom incoherent scatter radar during a 40 h period containing a storm with that modeled by the Assimilative Mapping of Ionospheric Electrodynamics (AMIE) procedure and (2) employing an magnetosphere-ionosphere (M-I) coupling model to analyze the theoretical dependence of Joule heating estimates on the spatial resolution of the inputs. We find that as compared with Sondrestrom measurements, a much larger contribution from correlation between conductance and squared electric field (positive for AMIE and negative for Sondrestrom) partially compensates for a much smaller mean-squared electric field, such that the overall average Joule heating rate modeled by AMIE is 29% less than measured by Sondrestrom. The underestimation of the mean-squared electric field was not associated with small-temporal-scale variability. Surprisingly, the M-I coupling model finds that coarse spatial resolution causes overestimation of the Joule heating rate, owing to the finding that the subresolution-scale spatial fluctuations in conductance and squared electric field are anticorrelated. When comparing estimates of the total Joule heating over a period of time, the increased Joule heating arises as a larger contribution from temporal correlation between conductance and squared electric field, which overcompensates for the reduced mean-squared electric field. Therefore, the difference in the Sondrestrom and AMIE correlation contributions might be explained by a difference in spatial resolution.
Determination of thermodynamic parameters in lariat ether complexes using ion-selective electrodes

Constantes de stabilite des complexes de Na + et K + avec des derives substitues en 2 de 15-crown-5
Aqueous Trichloroacetic Acid: Another Useful Reagent for Highly Selective 5′-Desilylation of Multisilylated Nucleosides

Abstract Highly selective 5′-desilylation of multisilylated nucleosides can be achieved in excellent yield by treatment with 4.2 M aqueous trichloroacetic acid:THF (1:4) at 0°C.
Shallow plumbing systems for small-volume basaltic volcanoes

Eruptive dynamics in basaltic volcanoes are controlled, in part, by the conduit geometry. However, uncertainties in conduit shape and dike-to-conduit transition geometry have limited our predictive capability for hazards assessments. We characterize the subvolcanic geometry of small-volume basaltic volcanoes (magmatic volatile-driven eruptions, 0.1 to 0.5 km3) based on a synthesis of field studies of five basaltic volcanoes exposed to varying degrees by erosion and exhibiting feeder dikes, conduits, and vent areas ≤250 m depth. Study areas include East Grants Ridge (New Mexico, USA), Basalt Ridge, East Basalt Ridge, Paiute Ridge, and Southeast Crater Flat (Nevada, USA). Basaltic feeder dikes 250 to 100 m deep have typical widths of 4–12 m, with smooth host-rock contacts (rhyolite tuff). At depths less than 100 m, heterogeneities in the host rock form preferential pathways for small dike splays and sills, resulting in a 30-m effective width at 50 m depth. The development of a complex conduit at depths less than 70 m is reflected in bifurcating dikes and brecciation and incorporation of the country rock. The overall zone of effect at depths less than 50 m is ≤110 m wide (220 m elongated along the feeder dike). Based on comparisons with theoretical conduit flow models, the width of the feeder dike at depths from 250 to 500 m is expected to range from 1 to 10 m and is expected to decrease to about 1–2 m at depths greater than 500 m. The flaring shape of the observed feeder systems is similar to results of theoretical modeling using lithostatic pressure-balanced flow conditions. Sizes of observed conduits differ from modeled dimensions by up to a factor of 10 in the shallow subsurface (<50 m depth), but at depths greater than 100 m the difference is a factor of 2 to 4. This difference is primarily due to the fact that observed eroded conduits record the superimposed effects of multiple eruptive events, while theoretical model results define dimensions necessary for a single, steady eruption phase. The complex details of magma-host rock interactions observed at the study areas (contact welding, brecciation, bifurcating dikes and sills, and stoping) represent the mechanisms by which the lithostatic pressure-balanced geometry is attained. The similarity in the normalized shapes of theoretical and observed conduits demonstrates the appropriateness of the pressure-balanced modeling approach, consistent with the conclusions of Wilson and Head (J Geophys Res 86:2971–3001, 1981) for this type of volcano.
Solar activity geomagnetic field and terrestrial weather

Spectral analysis is used as an independent test of the reported association between interplanetary-magnetic-field structure and terrestrial weather. Spectra of the Ap geomagnetic activity index and the vorticity area index for the years from 1964 to 1970 are examined for common features that may be associated with solar-related phenomena, specifically for peaks in the power spectra of both time series with periods near 27.1 days. The spectra are compared in three ways, and the largest peak with the smallest probability estimate is found to occur at a period of 27.49 days. This result is considered to be statistically significant at the 98% level. It is concluded that the period derived from the Ap spectrum is related to solar rotation and that the analysis provides supporting evidence for a connection between the vorticity area index and solar activity.
Model simplification by asymptotic order of magnitude reasoning

Abstract One of the hardest problems in reasoning about a physical system is finding an approximate model that is mathematically tractable and yet captures the essence of the problem. This paper describes an implemented program AOM which automates a powerful simplification method. AOM is based on two domain-independent ideas: self-consistent approximations and asymptotic order of magnitude reasoning. The basic operation of AOM consists of five steps: (1) assign order of magnitude estimates to terms in the equations, (2) find maximal terms of each equation, i.e., terms that are not dominated by any other terms in the same equation, (3) consider all possible n -term dominant balance assumptions, (4) propagate the effects of the balance assumptions, and (5) remove partial models based on inconsistent balance assumptions. AOM also exploits constraints among equations and submodels. We demonstrate its power by showing how the program simplifies difficult fluid models described by coupled nonlinear partial differential equations with several parameters. We believe the derivation given by AOM is more systematic and easily understandable than those given in published papers.
Household wealth in the Czech Republic: A comparative perspective

Abstract This paper focuses on household wealth dynamics in the Czech Republic. We estimate benchmark levels of household financial assets and liabilities on the basis of a comparison with Group of Seven (G-7) countries and compare them with the actual levels. Our results show that a further increase in both assets and liabilities would be justified by economic fundamentals. Furthermore, the G-7 benchmark indicates that both the level and composition of assets will need to change in the Czech Republic in response to the pressures that will arise from an aging population and the expected transfer of risks to households.
Public goods, taxes, and takings

Abstract Blume, Rubinfeld, and Shapiro [Blume, L., Rubinfeld, D., & Shapiro, P. (1984). The taking of law: When should compensation be paid? Quarterly Journal of Economics, 99, 71–92] first showed that compensation for takings can lead to a moral hazard problem that results in overinvestment in land suitable for public use. To the contrary, this paper shows that when compensation is financed by a proportional property tax, the compensation rule is irrelevant regarding the level of investment landowners make in their property, as well as the amount of land they authorize the government to acquire, both of which will be efficient. Intuitively, landowners recognize the equivalence of taxes and takings in budgetary terms, causing the distortionary effects of compensation and property taxation to cancel each other out through the balanced budget condition.
The effects of gusts on the fluctuating airloads of airfoils in transonic flow

Unsteady interactions of distributed and sharp-edged gusts with a stationary airfoil have been analyzed in two-dimensional transonic flow.A simple method of introducing such disturbances has been numerically implemented within the framework of unsteady, transonic small-disturbance theory. Representative solutions for various airfoils subjected to chordwise and transverse gusts show that the strength and unsteady motion of the shock wave on the airfoil significantly affect the flowfield development and, consequently, the dynamic airloads. Also a study was made of the reductions in the unsteady airloads that can be achieved by the proper active control motion of a trailing-edge flap, and a simple gust-alleviation strategy was developed. However, the chordwise pressure distributions associated with gusts are very different from those produced by trailing-edge flap oscillations. Consequently, the fluctuating lift and the unsteady pitching moments cannot both be eliminated simultaneously.
THE ENERGY DEPENDENCE OF MILLISECOND OSCILLATIONS IN THERMONUCLEAR X-RAY BURSTS

We examine the energy-resolved pulse profiles of 51 flux oscillations observed during the declines of thermonuclear X-ray bursts from accreting weakly magnetized neutron stars with the Rossi X-Ray Timing Explorer. In general, we find that (1) the amplitudes of the oscillations increase as a function of energy, and (2) the pulses observed in the higher energy bands arrive later than those in lower energy bands, although the magnitude of the energy dependence varies significantly from burst to burst. Averaging groups of bursts from individual sources, we demonstrate that fractional rms amplitudes of the oscillations increase as a function of energy by 0.25%-0.9% keV-1 between 3 and 20 keV and are as large as 20% in the 13-20 keV band. We also show that the average delays between pulses observed in the high- and low-energy bands are 0.002-0.007 cycles keV-1 between 3 and 20 keV. This amounts to total delays of 0.03-0.12 cycles between the lowest and highest energy bands or time delays that range from 100 to 200 μs. We model the oscillations as flux variations arising from temperature patterns on the surfaces of rapidly rotating neutron stars. In this framework, we find that the increase in the pulse amplitude with photon energy can be explained if the cooler regions on the neutron star emit in the lower energy bands, reducing the flux variations there. On the other hand, the Doppler shifts caused by the rapid rotation of the neutron star should cause the hard pulses to precede the soft pulses by about 0.05 cycles (100 μs), in contrast to the observations. This suggests that the photons originating from the stellar surface are reprocessed by a hot corona of electrons before they reach the observer.
Transverse-Flow Gas Lens

The concept of a transverse-flow gas lens is described. In this device, gas flows between two parallel plates that are heated or cooled so as to generate a parabolic variation of index of refraction in the region between the plates. A laser beam, propagating normal to the gas flow, can then be diverged, converged, or focused. A single module acts like a cylindrical lens. The use of two or three modules, arranged in an orthogonal manner, provides a spherical lens. Equations and tables are provided for the design of one-, two-, and three-module configurations. The advantages of the transverse-flow gas lens (relative to a device with a flow along the optic axis) are 1) thermal blooming is minimized (due to short residence time of fluid in laser beam); 2) the index of refraction profile is the same throughout each module, leading to good beam quality; and 3) the system is readily scaleable. However, a longer distance along the optical axis may be needed by the transverse-flow lens.
The Timing and Information Content of Auditors' Exhibit Letters Relating to Auditor Changes

This study examines auditors' exhibit letters that are filed as part of reporting requirements for auditor changes. The two other reporting requirements (an initial 8‐K filing by the client and the AICPA notification letter sent by the auditor) have been the subject of prior work (Schwartz and Soo 1996a; Ettredge et al. 2001). The auditor's exhibit letter, in which the auditor is required to comment on client disclosures in the initial 8‐K, is intended to ensure accurate reporting by the client particularly on potentially troublesome conditions such as reportable events, disagreements, and resignations. I investigate the content, timeliness, and informativeness of the auditors' letters. The results indicate a low incidence of inconsistencies between the initial 8‐K and the auditor's letter, and a low degree of noncompliance with the timing requirements suggesting that the auditor's exhibit letter contributes positively to the monitoring of corporate disclosures concerning auditor changes. Importantly, a r...
Fast linear discriminant analysis using binary bases

Linear Discriminant Analysis (LDA) is a widely used technique for pattern classification. It seeks the linear projection of the data to a low dimensional subspace where the data features can be modelled with maximal discriminative power. The main computation in LDA is the dot product between LDA base vector and the data point which involves costly element-wise floating point multiplications. In this paper, we present a fast linear discriminant analysis method called binary LDA (B-LDA), which possesses the desirable property that the subspace projection operation can be computed very efficiently. We investigate the LDA guided non-orthogonal binary subspace method to find the binary LDA bases, each of which is a linear combination of a small number of Haar-like box functions. We also show that B-LDA base vectors are nearly orthogonal to each other. As a result, in the non-orthogonal vector decomposition process, the computationally intensive pseudo-inverse projection operator can be approximated by the direct dot product without causing significant distance distortion. This direct dot product projection can be computed as a linear combination of the dot products with a small number of Haar-like box functions which can be efficiently evaluated using the integral image. The proposed approach is applied to face recognition on ORL and FERET dataset. Experiments show that the discriminative power of binary LDA is preserved and the projection computation is significantly reduced.
Plemelj Projection Operators over Domain Manifolds

Plemelj projection operators are introduced for spaces of square integrable functions defined over the boundaries of a class of compact real n-dimensional manifolds lying in C^n. These manifolds posses many properties similar to domains in R^n, and are consequently called domain manifolds. The key ingredients used here are techniques from both real and complex Clifford analysis. Analogues of the Kerzman-Stein kernel and Szego projection operators ar introduced, and their conformal covariance is described.
Stereoselective 1,2-cis-galactosylation assisted by remote neighboring group participation and solvent effects

Abstract Iodonium-ion promoted glycosylations in 1,4-dioxane/toluene with galactosyl donors having an electron-donating neighboring group participating functionality at C-4 give exceptional high α-anomeric selectivities.
The size of a hypergraph and its matching number

More than forty years ago, ErdAs conjectured that for any $t \leq \frac{n}{k}$ , every k-uniform hypergraph on n vertices without t disjoint edges has at most max ${\binom{kt-1}{k}, \binom{n}{k}-\binom{n-t+1}{k}\}$ edges. Although this appears to be a basic instance of the hypergraph Turan problem (with a t-edge matching as the excluded hypergraph), progress on this question has remained elusive. In this paper, we verify this conjecture for all $t . This improves upon the best previously known range $t = O\bigl(\frac{n}{k^3}\bigr)$ , which dates back to the 1970s.
Safer Conditions for the Curtius Rearrangement of 1,3,5‐Benzenetricarboxylic Acid

Abstract A rapid method to prepare 1,3,5‐triaminobenzene and its derivatives is the tris‐Curtius rearrangment of 1,3,5‐benzenetricarboxylic acid. The hazards associated with the acyl azide route are minimized by using 1,2‐dichloroethane as solvent. A second method that avoids acyl azide preparation uses diphenylphosphoryl azide to yield the tricarbamate in one step.
Concurrency coordination in a locally distributed database system

A database is called internally consistent (or just consistent) with respect to a given set of invariant properties if, in the absence of any database activity, the above said invariants hold true. These properties reflect relations among objects of the application domain and characterize its semantic consistency (e.g., 'last name appears first on all government forms'). Because a single database may support many different applications, these relations are generally assumed to be known solely by the database user and not by the database designer. The very definition of a transaction (a sequence of primitive database activities which, when acting alone, preserves, as a whole, all invariants) is in recognition of the fact that it is the user's duty to guarantee the integrity of the data he manipulates.
Do sell-side stock analysts exhibit escalation of commitment?

This paper presents evidence that when an analyst makes an out-of-consensus forecast of a company's quarterly earnings that turns out to be incorrect, she escalates her commitment to maintaining an out-of-consensus view on the company. Relative to an analyst who was close to the consensus, the out-of-consensus analyst adjusts her forecasts for the current fiscal year's earnings less in the direction of the quarterly earnings surprise. On average, this type of updating behavior reduces forecasting accuracy, so it does not seem to reflect superior private information. Further empirical results suggest that analysts do not have financial incentives to stand by extreme stock calls in the face of contradictory evidence. Managerial and financial market implications are discussed.
A Bayesian approach to the empirical valuation of bond options

In this paper we propose and implement a Bayesian procedure for the empirical valuation of bond options given the observed term structure of interest rates, and given assumptions about the time series behavior of the instantaneous spot rate. The Bayesian approach is motivated by the extreme multicollinearity in the cross-sectional data. The multicollinearity is caused by some local identification problems in the likelihood function. These same singularities motivate the choice of prior. The proposed method is applied to a dataset of Dutch bond prices.
Synthetic and mechanistic aspects of the regioselective base-mediated reaction of perfluoroalkyl- and perfluoroarylsilanes with heterocyclic N-oxides

The scope and mechanistic implications of the direct transformation of heterocyclic N-oxides to 2-trifluoromethyl-, and related perfluoroalkyl- and perfluoroaryl-substituted N-heterocycles has been studied. The reaction is effected by perfluoroalkyl- and perfluorophenyltrimethylsilane in the presence of strong base. In situ displacement of the para-fluoro substituent in the pentafluorophenyl ring and the methoxy group in 8-methoxyquinolines with additional nucleophiles allows for further site-selective refunctionalization of the N-heterocyclic products.
One- and Two-Neutron Halos in Effective Field Theory

I discuss recent work our group has undertaken on effective-field-theory analyses of experimental data pertaining to one- and two-neutron halo nuclei.
The repair of wounds in the integument of insects

Phenolases play two important roles in insects. They are responsible for the darkening of all wounded tissues, and for the hardening and darkening of the cuticle. The phenolase involved in the hardening and darkening of abrasions in Calpodes is produced by the activation of a proenzyme. Both the proenzyme and the activator are localized in the epicuticle. The proenzyme is soluble in Ringer solution but the phenolase is insoluble. The phenolase activity is limited by the availability of substrate molecules, which are maintained at a constant low level by the epidermis. The epidermis is a barrier between the haemolymph and the cuticle and controls the quantity and type of molecules secreted. It is calculated that the total complement of substrate molecules for the phenolase in the cuticle is replaced very rapidly by the epidermis. The cuticle of Sarcophaga contains both a phenolase used in puparium formation and a prophenolase which is activated on injury as in Calpodes. Musca autumnalis has a hard but colourless puparium, but no phenolase in its larval cuticle. In Sarcophaga the phenolase produced from the prophenolase by wounding differs in substrate specificity from the phenolase which is already present in the cuticle for puparium formation. The cuticle which darkens in the wound reaction may be analogous to a partial exocuticle by reducing permeability when the epicuticle is damaged.
Distributed minimal residual (DMR) method for acceleration of iterative algorithms

Abstract A new method for enhancing the convergence rate of iterative schemes for the numerical integration of systems of partial differential equations has been developed. It is termed the Distributed Minimal Residual (DMR) method, and is based on general Krylov subspace methods. The DMR method differs from the Krylov subspace methods by the fact that the iterative acceleration factors are different from equation to equation in the system. At the same time, the DMR method can be viewed as an incomplete Newton iteration method. The DMR method has been applied to Euler equations of gasdynamics and incompressible Navier-Stokes equations. All numerical test cases were obtained using either explicit four stage Runge-Kutta or Euler implicit time integration. The DMR method was found capable of reducing the computation time by 20–80% depending on the test case. When directly compared with an implicit residual smoothing, the DMR method performed consistently better and more reliably. The formulation for the DMR method is general in nature and can be applied to explicit and implicit iterative algorithms for arbitrary systems of partial differential equations.
Conversion of hydrosilanes to alkoxysilanes catalyzed by Cp2TiCl2/nBuLi

Abstract The combination of Cp 2 TiCl 2 and n BuLi provides an effective catalyst for alcoholysis of the model silanes n-HexSiH 3 , PhMeSiH 2 , Ph 2 SiH 2 and PhMe 2 SiH by ethanol, isopropanol, t-butyl alcohol and phenol. Increasing the steric bulk of the substituents on either the alcohol or the silane generally requires longer reaction periods and/or increasing temperature. All SiH bonds are converted to SiOEt groups by ethanol and a single SiH bond in secondary silanes and two SiH bonds in tertiary silanes are replaced by t-butyl alcohol. Diols including pinacol, 2,4-pentanediol and 2,5-hexanediol react with PhRSiH 2 (R  Me, Ph) to give 1,3-dioxa-2-silacyclopentanes, -hexanes and -heptanes, respectively. Attempts to form caged structures by condensation of primary silanes and triols was unsuccessful. Hydrolysis of PhRSiH 2 is promoted by Cp 2 TiCl 2 / n BuLi and the siloxane is produced in quantitative yield when R  Ph and a mixture of linear disiloxanes and trisiloxanes in addition to cyclopolysilanes are produced when R  Me. Other protic reagents including acids, mercaptans, amines and enolizable ketones did not react. The effects of reaction parameters such as temperature, silane to catalyst ratio, solvent, transition metal and replacements for n BuLi were also determined.
Synthesis of the (α,α-difluoroalkyl)phosphonate analogue of phosphoserine

Abstract The synthesis of the (α,α-difluoroalkyl)phosphonate analogue of L-phosphoserine, 5 , in a form appropriate for solid phase peptide synthesis, is reported. Two independent routes are described, starting from L-serine or (R)-isopropylideneglycerol. In each case, PCF 2 C bond formation is achieved by triflate displacement with diethyl lithiodifluoromethylphosphonate.
Influence of peptide dipoles and hydrogen bonds on reactive cysteine pKa values in fission yeast DJ‐1

Cysteine residues with depressed pKa values are critical for the functions of many proteins. Several types of interactions can stabilize cysteine thiolate anions, including hydrogen bonds between thiol(ate)s and nearby residues as well as electrostatic interactions involving charged residues or dipoles. Dipolar stabilization of thiolates by peptide groups has been suggested to play a particularly important role near the N-termini of α-helices. Using a combination of X-ray crystallography, site-directed mutagenesis and spectroscopic methods, we show that the reactive cysteine residue (Cys111) in Schizosaccharomyces pombe DJ-1 experiences a 0.6 unit depression of its thiol pKa as a consequence of a hydrogen bond donated by a threonine side chain (Thr114) to a nearby peptide carbonyl oxygen at the N-terminus of an α-helix. This extended hydrogen bonded interaction is consistent with a sum of dipoles model whereby the distal hydrogen bond polarizes and strengthens the direct hydrogen bond between the proximal amide hydrogen and the cysteine thiol(ate). Therefore, our results suggest that the local dipolar enhancement of hydrogen bonds can appreciably stabilize cysteine thiolate formation. However, the substitution of a valine residue with a proline at the i + 3 position has only a minor effect (0.3 units) on the pKa of Cys111. As proline has a reduced peptide dipole moment, this small effect suggests that a more extended helix macrodipolar effect does not play a major role in this system. Database Structural models and diffraction data are available in the Protein Data Bank under the accession number(s) 4GDH (wild-type SpDJ-1), 4GE0 (T114P SpDJ-1) and 4GE3 (T114V SpDJ-1) Structured digital abstract SpDJ-1 and SpDJ-1 bind by x-ray crystallography (View interaction)
Nonequilibrium laminar boundary-layer flow of ionized air

Numerical calculations of the nonequilibrium ionized air boundary layer on a cone-shaped re-entry vehicle at several flight conditions are determined with a finite-difference scheme. The results of this investigation show that the electron density 15-ft downstream on a cone at re-entry velocity is approximately 10 electrons/cm at 150,000-ft alt, whereas at 100,000 ft, the value has increased to 10 electrons/cm. This investigation also shows the importance of considering the nonequilibrium aspects of the flow rather than the limiting cases of frozen or equilibrium flow. The study of the chemical reactions shows that atomic oxygen is mainly produced from the dissociation of molecular oxygen, whereas atomic nitrogen results mainly from two of the shuffle reactions. The production of nitric oxide comes from the shuffle reactions. For distances up to 15-ft downstream from the tip and for conditions considered, none of the chemical reactions are near equilibrium.
A scalable and self-adapting notification framework for healthcare information systems

There has been a great interest in publish/subscribe systems in recent years. This interest, coupled with the pervasiveness of light-weight electronic devices, such as cellular phones and personal digital assistants, has opened a new arena in publish/subscribe networks. Currently, many broker overlay networks are static and rarely change in structure. Often, a network overlay structure is predefined or manually modified. This paper presents a dynamic broker network for disseminating critical lab and patient information in a Healthcare information system. The reported work builds upon previous network optimization research on ad hoc publish/subscribe networks. The underlying framework utilizes user-defined cost functions to satisfy quality of service constraints. In essence, the broker network optimization problem is reduced to an incremental search problem to generate low cost network configurations. Certain reliability issues are also addressed by providing a scheduling algorithm to selectively retransmit information and handle broker connectivity failures.
Satisfaction in technology‐enabled service encounters

Purpose – This paper aims to determine the importance of the human touch in customer service interactions.Design/methodology/approach – The paper is based on two original studies using tech‐savvy respondents, utilizing a survey and scenario‐based research.Findings – The paper finds that, even for tech‐savvy customers, human touch is an important factor in both customer satisfaction and behavioral intentions.Research limitations/implications – The study is limited to US respondents and telephone‐based service encounters.Practical implications – This paper shows the importance of keeping some aspects of the human touch in customer encounters with the firm. Firms cannot rely on self‐service technology for all services.Originality/value – This paper fulfills a gap in the existing services literature, with a specific focus on valuing human interaction in technology‐enabled service encounters.
Synthesis and Suzuki–Miyaura Cross-Coupling Reactions of Potassium Boc-Protected Aminomethyltrifluoroborate with Aryl- and Hetaryl Halides

Potassium Boc-protected aminomethyltrifluoroborate, a primary aminomethyl equivalent, was synthesized successfully through a “one-pot” process. With this trifluoroborate, Suzuki–Miyaura cross-coupling reactions were investigated with a variety of both aryl and hetaryl chlorides in good to excellent yields.
Neurophysiologic effects of retrograde cerebral perfusion used for aortic reconstruction

Abstract Objective: The results of neurophysiologic monitoring using somatosensory evoked potentials (SSEPs) and electroencephalography (EEG) were analyzed to determine if retrograde cerebral perfusion (RCP) supported central nervous system electrical function during surgery that required temporary interruption of antegrade cerebral perfusion (IACP). Design: A prospective, observational study. Setting: A university hospital. Participants: Fifteen adult patients who underwent aortic reconstruction using RCP and three patients who underwent thoracic aortic operations using hypothermic circulatory arrest without RCP. Interventions: SSEPs and EEG were monitored continuously throughout the operation. Regression analysis was performed to determine the factors that affected the rate of decrease in SSEP amplitudes during IACP and the time required for SSEP and EEG activity to recover after antegrade cerebral perfusion (ACP) was restored. Measurements and Main Results: The amplitude of SSEPs that were elicited decreased over time after IACP The mean ± standard deviation (SD) time required for the brachial plexus (Erb's point), cervicomedullary junction (N13), and brainstem (N18) SSEPs to decrease to 0.5 of their original amplitude after IACP were 30 ± 2, 19 ± 2, and 16 ± 2 minutes, respectively. The rate of decrease in the N18 SSEP amplitude after IACP correlated positively to the fraction of no-flow time (p = 0.01). Conclusion: RCP attenuated the rate of decay in SSEP amplitudes during IACP. This suggested that RCP had a measurable physiologic effect on central nervous system function and may increase the time that ACP can be safely interrupted.
Curves in Cages: An Algebro-Geometric Zoo

This paper is concerned with families of plane algebraic curves that contain a given and quite special set of points X . We focus on the case in which the set X is formed by transversally intersecting pairs of lines selected from two given finite families. The union of all lines from both families is called a cage (this notion of cage will be made more precise later), and the intersection X consists of points at which a line from the first family intersects a line from the second. The points of X are called the nodes of the cage. This is a particular case of a more general problem. Let X be the intersection set of two plane algebraic curves D and E that do not share a common component, that is, do not contain a common irreducible curve. If d and e denote the degrees of D and E , respectively, then X consists of at most d · e points. When the cardinality of X is exactly d · e, X is called a complete intersection (complete intersections have many nice properties). How does one describe polynomials of degree at most k that vanish on a complete intersection X or on its subsets? This problem has a glorious history (see [1], [2], or [3]) and its generalizations are a subject of active and exciting research [4], [5], [6], [7], [8], [9]. When k is much larger then d · e, points of X impose independent restrictions on polynomials of degree k. However, for small k these restrictions fail to be independent. In such cases, we can look for maximal subsets of X that impose independent constraints. In this article, we deal with the special case of this classical problem suggested earlier, namely, the case in which both plane curves D and E are simply unions of lines and the union D ∪ E is the (d× e)-cage in question. Note that D is the zero set of a product of d linear polynomials, while E is the zero set of a product of e linear polynomials. Hence, the degrees of D and E are d and e, respectively. In order to simplify our terminology, we color the lines from D red and the ones from E blue.
Retail Contracting and Organizational Form: Alternatives to Chain Affiliation in the Motel Industry

Most of the existing empirical literature on franchising investigates the share of company-owned versus franchised establishments within large retail firms. This literature typically has not considered the decision of a business owner to operate an independent business or to become a franchisee. This paper empirically analyzes what determines whether independent ownership or affiliation is observed, using data on the affiliation status of 2,293 motel establishments located throughout the United States. Heterogeneity in the underlying economic environment helps explain affiliation choices at the establishment level. The results also suggest that failure to consider independent establishments may explain the puzzling negative correlation between risk and vertical integration commonly found in the empirical franchising literature.
Pair Multiplicities and Pulsar Death

Through a simple model of particle acceleration and pair creation above the polar caps of rotation-powered pulsars, we calculate the height of the pair formation front (PFF) and the dominant photon emission mechanism for the pulsars in the Princeton catalog. We find that for most low- and moderate-field pulsars, the height of the PFF and the final Lorentz factor of the primary beam is set by nonresonant inverse Compton scattering (NRICS), in the Klein-Nishina limit. NRICS is capable of creating pairs over a wide range of pulsar parameters without invoking a magnetic field more complicated than a centered dipole, although we still require a reduced radius of curvature for most millisecond pulsars. For short-period pulsars, the dominant process is curvature radiation, while for extremely high field pulsars, it is resonant inverse Compton scattering (RICS). The dividing point between NRICS dominance and curvature dominance is very temperature dependent; large numbers of pulsars dominated by NRICS at a stellar temperature of 106 K are dominated by curvature at 105 K. Our principle result is a new determination of the theoretical pulsar death line. Proper inclusion of ICS allows us to reach the conclusion that all known radio pulsars are consistent with pair creation above their polar caps, assuming steady acceleration of a space charge-limited particle beam. We identify a new region of the P- diagram where slow pulsars with narrow radiation beams should be found in sufficiently large surveys. We also show that the injection rate of electrons and positrons into the Crab Nebula inferred from the polar cap pair creation model at the present epoch (1039 electrons and positrons s-1) suffices to explain the nebular X-ray and ?-ray emission, the best empirical measure of the instantaneous particle-loss rate from any pulsar, but that the contemporary injection rate is about a factor of 5 below the rate averaged over the nebula's history required to explain the nebular radio emission (assuming that the nebular radio source is homogeneous). It is not clear whether this discrepancy can be resolved by evolutionary effects and by better treatment of nebular inhomogeneity or is an indication of another particle source in the pulsar's magnetosphere.
Bowling in Hawaii Examining the Effectiveness of Sports-Based Tourism Strategies

We use daily airplane arrival data from Hawaii's Department of Business, Economic Development, and Tourism to determine the net change in tourism for a variety of sporting events. We find three eve...
The political economy of tobacco control spending

This article investigates why some US states spend so comparatively little on Tobacco Control Funding (TCF). We find that cross-state variation in spending on tobacco control is significantly driven by a tobacco special interest effect.