cssi/SciSciGPT-SciSciNet huggingface dataset:
Detecting the Baryons in Matter Power Spectra

We examine power spectra from the Abell/ACO rich cluster survey and the Two-Degree Field Galaxy Redshift Survey (2dFGRS) for observational evidence of features produced by the baryons. A nonnegligible baryon fraction produces relatively sharp oscillatory features at specific wavenumbers in the matter power spectrum. However, the mere existence of baryons will also produce a global suppression of the power spectrum. We look for both of these features using the false discovery rate statistic. We show that the window effects on the Abell/ACO power spectrum are minimal, which has allowed for the discovery of discrete oscillatory features in the power spectrum. On the other hand, there are no statistically significant oscillatory features in the 2dFGRS power spectrum, which is expected from the survey's broad window function. After accounting for window effects we apply a scale-independent bias to the 2dFGRS power spectrum, PAbell(k) = b2P2dF(k) and b = 3.2. We find that the overall shapes of the Abell/ACO and the biased 2dFGRS power spectra are entirely consistent over the range 0.02 ≤ k ≤ 0.15 h Mpc-1. We examine the range of Ωmatter and baryon fraction, for which these surveys could detect significant suppression in power. The reported baryon fractions for both the Abell/ACO and 2dFGRS surveys are high enough to cause a detectable suppression in power (after accounting for errors, windows, and k-space sampling). Using the same technique, we also examine, given the best-fit baryon density obtained from big bang nucleosynthesis, whether it is possible to detect additional suppression due to dark matter-baryon interaction. We find that the limit on dark matter cross section/mass derived from these surveys is the same as those ruled out in a recent study by Chen, Hannestad, & Scherrer.
Infrared Luminosity Function of the Coma Cluster

Using mid-IR and optical data, we deduce the total infrared (IR) luminosities of galaxies in the Coma Cluster and present their IR luminosity function (LF). The shape of the overall Coma IR LF does not show significant differences from the IR LFs of the general field, which indicates the general independence of global galaxy star formation from environment up to densities ~40 times greater than in the field (we cannot test such independence above LIR ≈ 1044 ergs s-1). However, a shallower faint-end slope and a smaller L are found in the core region (where the densities are still higher) compared to the outskirt region of the cluster, and most of the brightest IR galaxies are found outside the core region. The IR LF in the NGC 4839 group region does not show any unique characteristics. By integrating the IR LF, we find a total star formation rate in the cluster of about 97.0 M☉ yr-1. We also studied the contributions of early- and late-type galaxies to the IR LF. The late-type galaxies dominate the bright end of the LF, and the early-type galaxies, although only making up a small portion (≈15%) of the total IR emission of the cluster, contribute greatly to the number counts of the LF at LIR < 1043 ergs s-1.
High-order RKDG Methods for Computational Electromagnetics

In this paper we introduce a new RKDG method for problems of wave propagation that achieves full high-order convergence in time and space. The novelty of the method resides in the way in which it marches in time. It uses an mth-order m-stage, low storage SSP-RK scheme which is an extension to a class of non-autonomous linear systems of a recently designed method for autonomous linear systems. This extension allows for a high-order accurate treatment of the inhomogeneous, time-dependent terms that enter the semi-discrete problem on account of the physical boundary conditions. Thus, if polynomials of degree k are used in the space discretization, the RKDG method is of overall order m = k + 1, for any k > 0. Moreover, we also show that the attainment of high-order space--time accuracy allows for an efficient implementation of post-processing techniques that can double the convergence order. We explore this issue in a one-dimensional setting and show that the superconvergence of fluxes previously observed in full space--time DG formulations is also attained in our new RKDG scheme. This allows for the construction of higher-order solutions via local interpolating polynomials. Indeed, if polynomials of degree k are used in the space discretization together with a time-marching method of order 2k + 1, a post-processed approximation of order 2k + 1 is obtained. Numerical results in one and two space dimensions are presented that confirm the predicted convergence properties.
Petrogenesis of the Barcroft pluton, northern White-Inyo Mountains, east-central California

The White-Inyo Range lies within the regional transition from Paleozoic-Precambrian North American continental basement to outboard Mesozoic and younger accreted terranes and a superimposed Andean-type arc. In the central White Mountains, the metaluminous Barcroft granodiorite invaded a major NE-striking, SE-dipping high-angle reverse fault—the Barcroft break. Because it is a relatively isolated igneous body and is well exposed over an elevation range of 1,500–4,000 m, its thermal history and that of the surrounding superjacent section are clearer than those of nearly coeval, crowded plutons emplaced in the hotter Sierra Nevada belt. The Barcroft pluton was emplaced as a compositionally heterogeneous series of areally scattered melt pulses episodically injected over the approximate interval 167–161 Ma. The oldest dated rocks are relatively quartzofeldspathic, whereas the youngest is more ferromagnesian, suggesting progressive partial fusion of a relatively mafic protolith. Heavy rare earth-enriched zircons indicate that Barcroft melts were derived at mid-crustal depths from a previously emplaced metabasaltic protolith containing plagioclase but lacking garnet. Granodioritic magma genesis involved the possible mixing of mafic and felsic melts, as well as very minor assimilation of country rocks, but mainly by fractional fusion and crystallization. Bulk chemical, rare earth, and isotopic data suggest that analyzed Barcroft rocks are members of a single suite. Granodioritic rocks are slightly more magnetite-rich at higher elevations on the NE, nearer the roof of the pluton. Earlier thermobarometry chronicled cooling and re-equilibration of the Barcroft pluton from its margins inward, as well as from mid-crustal generation depths of ~25 km through ascent and stalling at ~10–12 km. Refractory phase assemblages crystallized along the pluton margins, whereas subsolidus minerals in the interior of the of body continued to exchange with upper crustal deuteric and surficial aqueous fluids during exhumation and cooling.
Mobile Lid Convection Beneath Enceladus' South Polar Terrain

Enceladus' south polar region has a large heat flux, 55-110 milliwatts per square meter (or higher), that is spatially associated with cryovolcanic and tectonic activity. Tidal dissipation and vigorous convection in the underlying ice shell are possible sources of heat; however, prior predictions of the heat flux carried by stagnant lid convection range from F(sub conv) ~15 to 30 milliwatts per square meter, too low to explain the observed heat flux. The high heat flux and increased cryovolcanic and tectonic activity suggest that near-surface ice in the region has become rheologically and mechanically weakened enough to permit convective plumes to reach close to the surface. If the yield strength of Enceladus' lithosphere is less than ~1-10 kPa, convection may instead occur in the mobile lid" regime, which is characterized by large heat fluxes and large horizontal velocities in the near-surface ice. I show that model ice shells with effective surface viscosities between 10(exp 16) and 10(exp 17) Pa s and basal viscosities between 10(exp 13) and 10(exp 15) Pa s have convective heat fluxes comparable to that observed by the Cassini Composite Infrared Spectrometer. If this style of convection is occurring, the south polar terrain should be spreading horizontally with v~1-10 millimeter per year and should be resurfaced in ~0.1-10 Ma. On the basis of Cassini imaging data, the south polar terrain is ~0.5 Ma old, consistent with the mobile lid hypothesis. Maxwell viscoelastic tidal dissipation in such ice shells is not capable of generating enough heat to balance convective heat transport. However, tidal heat may also be generated in the near-surface along faults as suggested by Nimmo et al. and/or viscous dissipation within the ice shell may occur by other processes not accounted for by the canonical Maxwell dissipation model.
Efficiency results of MLE and GMM estimation with sampling weights

This paper examines GMM and ML estimation of econometric models and the theory of Hausman tests with sampling weights. Weighted conditional GMM can be more efficient than weighted conditional MLE, an inefficient alternative to full information MLE under choice-based sampling, unless regressions have homoscedastic additive disturbances or sampling weights are independent of exogenous variables. GMM variances are necessarily smaller without sampling weights if GMM is the same as MLE or disturbances are homoscedastic, but not in general. Taking into account the dependence of sampling weights on parameters improves the efficiency of estimation.
Incorporating Delay Effects into Airport Runway Pavement Management Systems

This paper presents an approach to address pavement management decision problems at airports with multiple runways. It relaxes some of the underlying assumptions made in previous studies and explicitly considers time requirements for runway reconstruction, deterioration dependence on traffic levels, and the growth of traffic demand over time. A finite-horizon dynamic program is formulated to investigate the interplays among maintenance and repair (M&R) action time, functional interdependence between runways, and traffic growth. Results from computational studies reveal these interplays, in particular the tradeoff between present M&R action and delay cost and long-term benefits brought by significantly upgrading pavement conditions through reconstructing runways. Sensitivity analyses suggest that baseline demand, demand growth rate, and the parameter differentiating traffic-dependent transition probabilities significantly affect optimal M&R decisions and total expected cost to go.
Fashioning Australia's Forests

Preface. Acknowledgements. Abbreviations. Patterns of Australia's Forests. Introduction. Fashioning, 1850s and 1960s. 1: Forests for home and empire. 2: Forests for industrialisation. 3: Forests for conservation and delight. Changing, 1970s and 1980s. 4: Forests for Japan. 5: Forests for work and regional development. 6: Forests for existence and experience. Contesting, from the 1970s. 7: Contesting existence, ecology and experience. 8: Contesting industries and regions. 9: Contesting politics and the state. Creating, 1990s and Beyond. 10: Forests prospects in a changing world. Appendix. Notes. Bibliography. Figures and Plates
Total synthesis of (+)-brasilenyne. Application of an intramolecular silicon-assisted cross-coupling reaction.

The first enantioselective total synthesis of (+)-brasilenyne (1) has been achieved in 19 linear steps, with 5.1% overall yield from l-(S)-malic acid. The construction of the oxonin core containing a 1,3-cis,cis diene unit was accomplished with a tandem ring-closing metathesis/silicon-assisted intramolecular cross-coupling reaction. In addition, a key propargylic stereogenic center was created through a novel, highly diastereoselective ring opening of a 1,3-dioxolanone promoted by TiCl4. This reaction proceeded through an oxocarbenium ion intermediate and the asymmetric induction was fully controlled by l-malic acid residue. The C(8) stereogenic center was set by a reagent-controlled asymmetric allylboration.
Efficient Synthesis of Fluoren-9-ones by the Palladium-Catalyzed Annulation of Arynes by 2-Haloarenecarboxaldehydes

Fluoren-9-ones and derivatives are readily prepared in good yields by the annulation of in situ generated arynes by 2-haloarenecarboxaldehydes in the presence of a palladium catalyst.
Degree-growth of monomial maps

For projectivizations of rational maps, Bellon and Viallet defined the notion of algebraic entropy using the exponential growth rate of the degrees of iterates. We want to call this notion to the attention of dynamicists by computing algebraic entropy for certain rational maps of projective spaces (Theorem 6.2) and comparing it with topological entropy (Theorem 5.1). The particular rational maps we study are monomial maps (Definition 1.2), which are closely related to toral endomorphisms. Theorems 5.1 and 6.2 that imply that the algebraic entropy of a monomial map is always bounded above by its topological entropy, and that the inequality is strict if the defining matrix has more than one eigenvalue outside the unit circle. Also, Bellon and Viallet conjectured that the algebraic entropy of every rational map is the logarithm of an algebraic integer, and Theorem 6.2 establishes this for monomial maps. However, a simple example using a monomial map shows that a stronger conjecture of Bellon and Viallet is incorrect, in that the sequence of algebraic degrees of the iterates of a rational map of projective space need not satisfy a linear recurrence relation with constant coefficients.
Survey for Transiting Extrasolar Planets in Stellar Systems. II. Spectrophotometry and Metallicities of Open Clusters

We present metallicity estimates for seven open clusters based on spectrophotometric indices from moderate-resolution spectroscopy. Observations of field giants of known metallicity provide a correlation between the spectroscopic indices and the metallicity of open cluster giants. We use χ2 analysis to fit the relation of spectrophotometric indices to metallicity in field giants. The resulting function allows an estimate of the target-cluster giants' metallicities with an error in the method of ±0.08 dex. We derive the following metallicities for the seven open clusters: NGC 1245, [M/H] = -0.14 ± 0.04; NGC 2099, [M/H] = +0.05 ± 0.05; NGC 2324, [M/H] = -0.06 ± 0.04; NGC 2539, [M/H] = -0.04 ± 0.03; NGC 2682 (M67), [M/H] = -0.05 ± 0.02; NGC 6705, [M/H] = +0.14 ± 0.08; NGC 6819, [M/H] = -0.07 ± 0.12. These metallicity estimates will be useful in planning future extrasolar planet transit searches, since planets may form more readily in metal-rich environments.
Jet correlations with identified particles from PHENIX: Methods and results

Azimuthal angle two particle correlations have been shown to be a powerful probe for extracting novel features of the interaction between hard scattered partons and the medium produced in Au+Au collisions at RHIC. At intermediate pT, 2–5 GeV/c, the jets have been shown to be significantly modified in both their particle composition and their angular distribution compared to p+p collisions. Additionally, angular two particle correlations with identified hadrons provide information on the possible role of modified hadronization scenarios such as partonic recombination, which might allow medium modified jet fragmentation by connecting hard scattered partons to low pT thermal partons. PHENIX has excellent particle identification capabilities and has developed robust techniques for extracting jet correlations from the large underlying event. We present recent PHENIX results from Au+Au collisions for a variety of pT and particle type combinations. We also present p+p measurements as a baseline. We show evidence that protons and anti-protons in the pT region of enhanced baryon and anti-baryon single particle production are produced in close angle pairs of opposite charge and that the strong modifications to the away side shape observed for charged hadron correlations are also present when baryons are correlated.
Rare-Gas Intercalation Into Fullerene Interstices

The authors review their neutron diffraction studies of the intercalation of the rare gases into the interstices of C{sub 60} at pressures ranging from 0 to 6 kbar, primarily at room temperature, but also at other temperatures. Room temperature compressibilities of C{sub 60} for both the face-centered-cubic and simple-cubic phases using Ar, which does not intercalate, as the pressure medium are in excellent agreement with the earlier work of David et al, while the values for He and Ne are slightly smaller than those using Ar. The rates of intercalation and release of Ne, at a number of different temperatures, have been measured and show that, at a given temperature, intercalation is much slower than release. Structural refinements of the Ne intercalated C{sub 60} have been carried out for room temperature samples at many different pressures. These data suggest that Ne only intercalates into the octahedral hole and that the occupancy increases smoothly with pressure. Intercalated materials are important technologically for their use as catalysts, waste storage media, solid-state batteries, molecular sieves, gettering materials, and in many other applications. Sometimes, intercalation endows the new material with remarkable properties.
Meta-selective C-H functionalization using a nitrile-based directing group and cleavable Si-tether.

A nitrile-based template that enables meta-selective C–H bond functionalization was developed. The template is applicable to a range of substituted arenes and tolerates a variety of functional groups. The directing group uses a silicon atom for attachment, allowing for a facile introduction/deprotection strategy increasing the synthetic practicality of this template.
Spectroscopic and chemical evidence for methylene singlet-triplet intersystem crossing in solution

Singlet-triplet intersystem crossing of methylene in perfluorohexane solution has been investigated by CIDNP. Evidence of this process is shown by the polarized absorption 1H-NMR signal of Cl3CCH2D, a triplet product, which is obtained upon direct irradiation of diazirine in perfluorohexane solution containing saturated deuteriochloroform. These results are confirmed by product analysis as a function of dilution by perfluorohexane. The rate constant for intersystem crossing for singlet methylene to triplet methylene is evaluated as ca. 8 x 108 S−1 from the data.
A brief history of the crack tip stress intensity factor and its application

The primary objective of this work is to discuss the origins, background and development of the elastic crack tip stress intensity factor, K, as they occurred. The further development of the three modes and the compilations of related formulas in the literature are discussed. The origins of applications to static crack growth stability, and sub-critical growth due to fatigue and environmental effects are included. Significant events such as the formation of the ASTM committee on Fracture Mechanics, the adoption of Damage Tolerance Analysis by the aircraft industry using Fracture Mechanics as a basis, and the further extension of the methods to large-scale plasticity conditions are presented. Finally a discussion of early predictions of crack paths is discussed.
SEIBERG–WITTEN INVARIANTS OF 4-MANIFOLDS WITH FREE CIRCLE ACTIONS

The main results of this paper describes a formula for the Seiberg–Witten invariant of a 4-manifold which admits a nontrivial free circle action. We use this theorem to produce a nonsymplectic 4-manifold with a free circle action whose orbit space fibers over circle. We also describe a nontrivial 3-manifold which is not the orbit space of any symplectic 4-manifold with a free circle action. A corollary of the main theorem is a formula for the 3-dimensional Seiberg–Witten invariants of the total space of a circle bundle over a surface.
A theory of necking in semi-crystalline polymers

Abstract Necking or cold drawing is a smoothed jump in cross-sectional area of long and thin bars (filaments or films) propagating with a constant speed. The necks in polymers, first observed about seventy years ago, are now commonly used in modern processing of polymer films and fibers. Yet till recently there was a lack in fundamental understanding of necking mechanism(s). For semi-crystalline polymers with co-existing amorphous and crystalline phases, recent experiments revealed that such a mechanism is related to unfolding crystalline blocks. Using this idea, this paper develops a theoretical model and includes it in a general continuum framework. Additionally, the paper explains the “forced” (reversible) elasticity observed in slowly propagating polymeric necks, and also briefly analyses the viscoelastic effects and dissipative heat generation when polymer necks propagate fast enough.
A comparison of thromboembolic prophylaxis in gynecologic oncology patients

The objective of this study was to compare two methods of thromboembolic prophylaxis: sequential compression devices alone (SCDs) vs. SCDs with subcutaneous low-dose unfractionated heparin (UH). A retrospective cohort study was conducted of 168 patients who had undergone surgery for suspected gynecological malignancies. These patients were examined for associated risk factors, method of prophylaxis, and incidence of clinically significant thromboembolic events. Of these patients, 94 (56%) received perioperative and postoperative sequential compression devices alone, while 74 (44%) received both SCDs and subcutaneous low-dose UH. The postoperative course of these patients, while in the hospital and after discharge, was followed for clinically evident thromboembolic complications. Univariate and multivariate analyses were performed. The two groups were comparable in terms of most risk factors, including age, stage, height, weight, body surface area, estimated blood loss, total anesthesia time, and nodal disease. Six of 94 patients (6.4%) in the SCDs group suffered from venous thromboembolism, while four of 74 patients (5.4%) who received both SCDs and low-dose UH had a thromboembolic event (chi2 P = 0.79). There was no difference in postoperative changes in platelet counts between the two groups. Heparin added additional cost, 105 extra minutes of nursing time per patient per admission, and additional pain for the patient. In conclusion, the addition of subcutaneous low-dose unfractionated heparin to SCDs for prophylaxis against deep venous thrombosis in women undergoing surgery for gynecologic malignancies does not improve the outcome. Adding heparin was more expensive, time consuming, and painful. Heparin should not be used with SCDs unless an additional benefit can be demonstrated in a randomized controlled trial.
Estimation of transitional probabilities of discrete event systems from cross-sectional survey and its application in tobacco control

In order to find better strategies for tobacco control, it is often critical to know the transitional probabilities among various stages of tobacco use. Traditionally, such probabilities are estimated by analyzing data from longitudinal surveys that are often time-consuming and expensive to conduct. Since cross-sectional surveys are much easier to conduct, it will be much more practical and useful to estimate transitional probabilities from cross-sectional survey data if possible. However, no previous research has attempted to do this. In this paper, we propose a method to estimate transitional probabilities from cross-sectional survey data. The method is novel and is based on a discrete event system framework. In particular, we introduce state probabilities and transitional probabilities to conventional discrete event system models. We derive various equations that can be used to estimate the transitional probabilities. We test the method using cross-sectional data of the National Survey on Drug Use and Health. The estimated transitional probabilities can be used in predicting the future smoking behavior for decision-making, planning and evaluation of various tobacco control programs. The method also allows a sensitivity analysis that can be used to find the most effective way of tobacco control. Since there are much more cross-sectional survey data in existence than longitudinal ones, the impact of this new method is expected to be significant.
Permeability and Thermal Transport in Compressed Open-Celled Foams

A computational methodology is proposed to describe the fluid transport in compressed open-celled metallic foams. Various unit-cell foam geometries are numerically deformed under uniaxial loads using a finite-element method. An algorithm is developed and implemented to deform the fluid domain mesh inside the unit-cell foam based on the deformed solid unit-cell geometry. Direct simulations of the fluid transport in these deformed meshes are then performed over a range of Reynolds numbers used in practical applications. The model is validated against available experimental results and correlations. A corrected model is proposed for the permeability of compressed foams as a function of strain for flows transverse to the direction of compression. The thermal conductivity of fluid-saturated foams is also computed. Compression of foams increases the conductivity transverse to the direction of compression and decreases the conductivity parallel to it.
Employee stock options as warrants

Abstract Previous studies ignore the fact that employee stock options are warrants because these options have been an insignificant component of firms’ capital structures. I show that this assumption is no longer correct. For example, for more than 36% of my sample firms, employee stock options represent a more significant claim on firm value than the firm’s debt and preferred stock combined . Moreover, in contrast to the suggestions of previous research, I show that employee stock options are a significant claim on firms throughout the economy, including larger firms, older firms, and firms in “Old Economy” industries. Finally, I show that the presumption in prior studies that employee stock options are not warrants causes a potential misunderstanding of the risk-shifting interests of securityholders and biases the analysis of capital structure issues.
The astrophysical environment of the solar birthplace

Our Sun, like all stars, formed within a cold molecular cloud. Astronomical observations and theory provide considerable detail into this process. Yet cosmochemical observations of short-lived radionuclides in primitive meteorites, in particular 60Fe, provide unequivocal evidence that the early solar system inherited fresh nucleosynthetic material from the core of a hot, massive star, almost certainly ejected in a supernova explosion. I give a short introduction to the fields of star formation and meteoritics and discuss how the reconciliation of their disparate clues to our origin places strong constraints on the environment of the solar birthplace. Direct injection of supernova ejecta into a protoplanetary disc or a dense molecular core is unlikely since their small sizes require placement unusually close to the massive star. Lower density molecular cloud clumps can capture more ejecta but the radionuclides decay during the slow gravitational collapse. The most likely scenario is on the largest scales v...
Exact theory of long-wavelength one-phonon amplitudes in atom-surface scattering

We derive an expression for the probability of creating or annihilating one {ital long}{minus}{ital wavelength} surface or bulk phonon during a scattering event, which depends on the {ital bulk} elastic constants but is independent of the details of the atom-target potential and of force-constant changes near the surface. This expression is exact if the inelastic scattering is weak'' (in a precisely defined sence). This theory should be experimentally verifiable, e.g., for 20-meV He atoms scattered from a W surface.
Trade, Growth and Wage Inequality in Bangladesh

Abstract Using model selection techniques based on out-of-sample predictive ability criterion in a Vector Autoregression (VAR) framework, this paper empirically examines the causal relations among growth, trade, and wage inequality in Bangladesh between 1971 and 2000. There is some evidence of bi-directional causality between growth and inequality and between trade and growth. That growth causes trade and that trade causes inequality are robust results. Furthermore, evidence strongly suggests that investment is important for trade, and the terms of trade between agricultural products and manufacturing products is an important causal determinant of both growth and trade.
Multi-parameter mechanisms with implicit payment computation

In this paper we show that payment computation essentially does not present any obstacle in designing truthful mechanisms, even for multi-parameter domains, and even when we can only call the allocation rule once. We present a general reduction that takes any allocation rule which satisfies "cyclic monotonicity" (a known necessary and sufficient condition for truthfulness) and converts it to a truthful mechanism using a single call to the allocation rule, with arbitrarily small loss to the expected social welfare.A prominent example for a multi-parameter setting in which an allocation rule can only be called once arises in sponsored search auctions. These are multi-parameter domains when each advertiser has multiple possible ads he may display, each with a different value per click. Moreover, the mechanism typically does not have complete knowledge of the click-realization or the click-through rates (CTRs); it can only call the allocation rule a single time and observe the click information for ads that were presented. On the negative side, we show that an allocation that is truthful for any realization essentially cannot depend on the bids, and hence cannot do better than random selection for one agent. We then consider a relaxed requirement of truthfulness, only in expectation over the CTRs. Even for that relaxed version, making any progress is challenging as standard techniques for construction of truthful mechanisms (as using VCG or an MIDR allocation rule) cannot be used in this setting. We design an allocation rule with non-trivial performance and directly prove it is cyclic-monotone, and thus it can be used to create a truthful mechanism using our general reduction.
On Time-Space Noncommutativity for Transition Processes and Noncommutative Symmetries

We explore the consequences of time-space noncommutativity in the quantum mechanics of atoms and molecules, focusing on the Moyal plane with just time-space noncommutativity . Space rotations and parity are not automorphisms of this algebra and are not symmetries of quantum physics. Still, when there are spectral degeneracies of a time-independent Hamiltonian on a commutative spacetime which are due to symmetries, they persist when θ0i≠0: they do not depend at all on θ0i. They give no clue about rotation and parity violation when θ0i≠0. The persistence of degeneracies for θ0i≠0 can be understood in terms of invariance under deformed noncommutative "rotations" and "parity". They are not spatial rotations and reflection. We explain such deformed symmetries. We emphasize the significance of time-dependent perturbations (for example, due to time-dependent electromagnetic fields) to observe noncommutativity. The formalism for treating transition processes is illustrated by the example of nonrelativistic hydrogen atom interacting with quantized electromagnetic field. In the tree approximation, the 2s→1s + γ transition for hydrogen is zero in the commutative case. As an example, we show that it is zero in the same approximation for θ0i≠0. The importance of the deformed rotational symmetry is commented upon further using the decay Z0→2γ as an example.
Some new classes of complex symmetric operators

We say that an operator T E B(H) is complex symmetric if there exists a conjugate-linear, isometric involution C: ℌ→ℌ so that T = CT * C. We prove that binormal operators, operators that are algebraic of degree two (including all idempotents), and large classes of rank-one perturbations of normal operators are complex symmetric. From an abstract viewpoint, these results explain why the compressed shift and Volterra integration operator are complex symmetric. Finally, we attempt to describe all complex symmetric partial isometries, obtaining the sharpest possible statement given only the data (dim ker T, dim ker T*).
Electrical Properties of Sand–Clay Mixtures Containing Trichloroethylene and Ethanol

A series of laboratory experiments that measured electrical properties and permeability was performed on carefully characterized sand–clay mixtures. Different mixtures and configurations of quartz sand and 10% Na-montmorillonite clay were investigated using solutions of NaCl, CaCl2, and deionized water. A sample containing 10% dispersed clay was also studied using fluids containing 20- and 500‐ppm trichloroethylene (TCE). Each sample’s electrical properties after fluid saturation were measured at frequencies between 10−2 and 106Hz by using the four-electrode method with Ag–AgCl inner electrodes at room temperature and 412kPa confining pressure, which corresponds to a soil depth of 15–20m. Our results show that adding TCE had a small effect on electrical resistivity: resistivity was greater at higher concentrations of TCE. The influence of TCE on electrical properties was most prominent in plots of loss tangent as a function of frequency. These plots showed that loss-tangent peaks occurred at ∼200Hz and th...
Special Cases of Friction and Applications

Two techniques for reducing friction forces are presented. The techniques are applied to the generalized problem of reducing the friction between kinematic pairs which connect a moveable link to a frame. The basic principles are: (1) Let the moveable link be supported by two bearings where the relative velocities of the link with respect to each bearing are of opposite directions. Thus the resultant force (torque) of friction acting on the link due to the bearings is approximately zero. Then, additional perturbation of motion parallel to the main motion of the moveable link will require only a very small force; (2) Let the perturbation in motion be perpendicular to the main motion. Equations are developed which explain these two methods. The results are discussed in relation to friction in geared couplings, gyroscope gimbal bearings and a rotary conveyor system. Design examples are presented.
The Major Critical Problem in the American University: Quality Teaching in the Freshman and Sophomore Years

One of the many activities of the AIBS is participation in the Cooperative Committee on the Teaching of Science and Mathematics of the AAAS which is involved in enhancing the teaching of science in our educational institutions. This Committee has been concerned with several basic problems, one of which deals with a proper and realistic balance between university teaching and research. In the large universities one often finds undergraduate teaching subordinate to research, whereas in our smaller colleges there may be no research because of the total commitment to a teaching program. Obviously, a reasonable balance, characteristic of each particular institution is not only desirable but in some institutions appears to be vital at this time. Thus our Committee recently endorsed the following position paper. Since this situation is not unique to departments of chemistry, the editors of BioScience believed that this "paper" should be republished for those biologists who may not have seen it in Chemical and Engineering News last summer. Both Dr. Lippincott and I would welcome any comments you might have concerning this matter.
Arctic Warming Signals from Satellite Observations

Global warming signals are expected to be amplified in the Arctic primarily because of ice-albedo feedback associated with the high reflectivity of ice and snow that blankets much of the region. The Arctic had been a poorly explored territory basically because of its general inaccessibility on account of extremely harsh weather conditions and the dominant presence of thick perennial ice in the region. The advent of satellite remote sensing systems since the 1960s, however, enabled the acquisition of synoptic data that depict in good spatial detail the temporal changes of many Arctic surface parameters. Among the surface parameters that have been studied using space based systems are surface temperature, sea ice concentration, snow cover, surface albedo and phytoplankton concentration. Associated atmospheric parameters, such as cloud cover, temperature profile, ozone concentration, and aerosol have also been derived. Recent observational and phenomenological studies have indeed revealed progressively changing conditions in the Arctic during the last few decades (e g , Walsh et al. 1996; Serreze et al 2000; Comiso and Parkinson 2004). The changes included declines in the extent and area of surfaces covered by sea ice and snow, increases in melt area over the Greenland ice sheets, thawing of the permafrost, warming in the troposphere, and retreat of the glaciers. These observations are consistent with the observed global warming that has been associated with the increasing concentration of greenhouse gases in the atmosphere (Karl and Trenberth 2003) and confirmed by modeling studies (Holland and Bitz, 2003). The Arctic system, however, is still not well understood complicated by a largely fluctuating wind circulation and atmospheric conditions (Proshutinsky and Johnson 1997) and controlled by what is now known as the Arctic Oscillation (AO) which provides a measure of the strength of atmospheric activities in the region (Thompson and Wallace 1998). Meanwhile, the observed Arctic conditions since the 1970s have been shown to exhibit a linear behavior that directly contradicts what has been expected from the A0 (Overland, 2005). The decade of the 1990s has been regarded as the warmest decade in the last century and current data indicates that the 2000s may be even a warmer decade than the 1990s further supporting the linear variability. In this paper, we use satellite data to gain insights into the warming Arctic and how the abnormally warm conditions during the last few years are reflected in the region.
Can patient injury claims be utilised as a quality indicator

Abstract Objectives To examine the association between patient injury claims and well-known quality indicators and to assess whether claims can be utilised in performance measurement. Methods Data were derived from administrative registers and comprised hip and knee replacement patients (n = 34 181) in Finland from 1998 to 2003. Hospital-level correlations were calculated between claims and quality indicators (5-year revision rate, 1-year deep infection rate, and 14-day readmission rate), while logistic regression analysis was used to analyze patient-level data for an association between claims and quality indicators. Results Correlations between claims and revisions as well as claims and infections were statistically significant, with correlation coefficients ranging from 0.21 to 0.62. In the regression analysis, both the revision and the infection indicator had a positive and statistically significant association with filing a claim (OR 1.002; 95% CI 1.001–1.003 and 1.001; 1.00005–1.001, respectively) and obtaining compensation (1.003; 1.001–1.005 and 1.001; 1.0003–1.002, respectively). Conclusions A claims indicator has the potential to be applied as a quality indicator. It should be complemented, however, with other indicators or actions to improve its acceptability by health professionals and to mitigate its possible undesirable effects.
Financial Leverage, CEO Compensation,and Corporate Hedging: Evidence from Real Estate Investment Trusts

This paper studies the determinants of corporate hedging practices in the REIT industry between 1999 and 2001. We find a positive significant relation between hedging and financial leverage, indicating the financial distress costs motive for using derivatives in the REIT industry. Using estimates of the Black–Scholes sensitivity of CEO’s stock option portfolios to stock return volatility and the sensitivity of CEO’s stock and stock option portfolios to stock price, we find evidence to support managerial risk aversion motive for corporate hedging in the REIT industry. Our results indicate that CEO’s cash compensation and the CEO’s wealth sensitivity to stock return volatility are significant determinants of derivative use in REITs. We also document a significant positive relation between institutional ownership and hedging activity. Further, we find that probability of hedging is related to economies of scale in hedging costs.
Constitutions As Relational Contracts: Explaining Procedural Safeguards in Municipal Charters

Theory: According to transaction resource theory, constitutions are relational contracts that facilitate long-term relationships. Transaction resource theory identifies 1) three types of risk in cooperation: coordination, division, and defection; 2) contextual factors, such as increasing population size and heterogeneity, that hinder the ability of the primary parties to mitigate these risks; and 3) the ability of third-party governance to facilitate cooperation. Procedural safeguards in a constitution create incentives -- albeit at a cost -- that mitigate the risks of third-party governance in the relationship between a governor and the governed. In that relationship, the three risks take the form of instability, unresponsiveness, and inefficiency. The theory draws upon collective choice theory, bargaining theory, and the economics of information. Hypothesis: As contextual constraints increase the three risks of governance, constitutions are more likely to contain safeguards crafted to mitigate them: allocations of authority across the branches of government, as in the veto, safeguard against instability; electoral rules, as in district versus at-large elections, safeguard against unresponsiveness; and provisions for direct democracy, as in initiatives, referenda and recalls, safeguard against inefficiency. Method: Factor analysis, logistic and multiple linear regression are applied to a sample of 145 municipal charters in 1970 for cities with populations of at least 25,000 in 1960. Results: Factor analysis discriminates among procedural safeguards in municipal charters consistent with their predicted purposes in mitigating the three risks. Regression analysis reveals the interdependence of the safeguards and their heightened likelihood under conditions where contextual factors heighten the risks. Significant contextual factors include constraints on municipal competition under state laws and increasing population size and income inequality.
Scaling behavior of granular particles in a vibrating box

Using numerical and analytic methods, we study the behavior of granular particles contained in a vibrating box. We measure, by molecular dynamics (MD) simulation, several quantities which characterize the system. These quantities — the density and the granular temperature fields, and the vertical expansion — obey scaling in the variable x = Af. Here, A and f are the amplitude and the frequency of the vibration. The behavior of these quantities is qualitatively different for small and large values of x. We also study the system using Navier-Stokes type equations developed by Haff. We develope a boundary condition for moving boundaries, and solve for the density and the temperature fields of the steady state in the quasi-incompressible limit, where the average separation between the particles is much smaller than the average diameter of the particles. The fields obtained from Haff's equations show the same scaling as those from the simulation. Also, the origin of the scaling can be easily understood. The behavior of the fields from the theory is consistent with the simulation data for small x, but they deviate significantly for large x. We argue that the deviation is due to the breakdown of the quasi-incompressibility condition at large x.
White flight and central-city loss: application of an analytic migration framework.

This paper utilizes an analytic migration framework to assess the aggregate impact of selected community-level factors on white population losses experienced in central cities of large metropolitan...
Enantioselective Organocatalytic Reductive Amination

The first enantioselective organocatalytic reductive amination reaction has been accomplished. The development of a new chiral phosphoric acid catalyst has provided a convenient strategy for the enantioselective construction of protected primary amines and provided a highly stereoselective method for the reductive amination of heterocyclic amines. A diverse spectrum of ketone and amine substrates can be accommodated in high yield and excellent enantioselectivity. This new protocol realizes a key benefit of reductive amination versus imine reduction, in that ketimines derived from alkyl−alkyl ketones are unstable to isolation, a fundamental limitation that is comprehensively bypassed using this direct organocatalytic reductive amination.
Design and Preparation of Organic−Inorganic Hybrid Catalysts

Solid catalysts provide numerous opportunities for recovering and recycling catalysts from reaction environments. These features can lead to improved processing steps, better process economics, and environmentally friendly industrial manufacturing. Thus, the motivating factors for creating recoverable catalysts are large.
Interaction of a weakly nonlinear laser pulse with a plasma

Based on a one-dimensional model, a perturbation expansion is carried out to solve the equations describing a weakly nonlinear laser pulse in a plasma in which the electrons are treated relativistically and the plasma frequency is much less than the laser frequency. To lowest order, the expansion yields two coupled equations for the vector and scalar potentials. For a pulse which is long compared with a plasma wavelength, the coupled equations reduce to the nonlinear Schr\"odinger equation with well-known soliton solutions. An initial pulse of hyperbolic-secant shape which is short compared with a plasma wavelength broadens and acquires a characteristic asymmetric shape with a steep trailing edge and a much broader, gently sloping front portion, and has a frequency and wave-number shift which vary from a positive value at the front to a negative value at the rear of the pulse. The peak and rear part of a short pulse are strongly influenced by nonlinear effects, whereas the front is governed primarily by linear dispersion. The average pulse frequency continually decreases as energy is lost to the plasma wake. The wake-field phase velocity is shown to be approximately equal to the velocity of the pulse peak.
Thermal convection effects in a thin viscous film

Abstract A perturbation solution is obtained for the temperature distribution for an isoviscous liquid film between nearly parallel walls, one wall being a flat stationary thermal insulator and the other a sliding perfect conductor with a sinusoidal waviness. Fluid and temperature gradients normal to the direction of sliding and parallel to the flat surfaces are neglected. The solution relates to a problem in lubricant films and serves as an exact solution for verification in approximations of the heat convection.
Triflic Acid-Mediated Rearrangements of 3-methoxy-8-oxabicyclo[3.2.1]octa-3,6-dien-2-ones: Synthesis of Methoxytropolones and Furans

Methoxytropolones are useful scaffolds for therapeutic development because of their known biological activity and established value in the synthesis of α-hydroxytropolones. Upon treatment with triflic acid, a series of 3-methoxy-8-oxabicyclo[3.2.1]octa-3,6-dien-2-ones rearrange rapidly and cleanly to form methoxytropolones. Interestingly, bicycles that are derived from dimethyl acetylenedicarboxylate (R2 = R3 = CO2Me) instead form furans as the major product.
Bismuth(III) bromide in organic synthesis. A catalytic method for the allylation of tetrahydrofuranyl and tetrahydropyranyl ethers

A bismuth bromide-catalyzed (10.0 mol %) multicomponent reaction involving the allylation of THF- and THP-ethers, followed by in situ derivatization with acetic anhydride to generate highly functionalized esters has been developed under solvent-free conditions. To the best of our knowledge, this is the first report of a catalytic procedure for the allylation of THF- and THP-ethers to yield ring-opened products.