cssi/SciSciGPT-SciSciNet huggingface dataset:
A Spherical Model for Starless Cores of Magnetic Molecular Clouds and Dynamical Effects of Dust Grains

In the current paradigm, isolated low-mass stars form out of magnetic molecular clouds as the clouds evolve because of ambipolar diffusion. A quantitative understanding of this process remains incomplete, because of both physical and technical complexities. As a step toward a quantitative theory for star formation, I explore further the evolution of magnetic clouds with a simplifying spherical geometry, studied first by Safier, McKee, & Stahler. The spherical model has several desirable features as well as some potentially serious difficulties. It highlights the pressing need for two-dimensional, fully dynamic models that treat the coupling between the magnetic field and the cloud matter properly. The model clouds exhibit substantial inward motion during the late stage of core formation, with velocities of order one-half the isothermal sound speed or more over most of the cloud, after a central density enhancement of about 102 (say, from 103 to 105 cm-3). Such precollapse motion may have been detected recently by Tafalla et al. and Williams et al. in the starless core L1544. The motion may also explain why starless dense cores typically last for only a few dynamic times and why they have small but significant nonthermal line widths. The clouds that I study have relatively low mass (of order 10 M☉) and initial magnetic pressure comparable to thermal pressure. They evolve into a density profile of a flat central plateau surrounded by an envelope whose density decreases with radius roughly as a power law, as found previously. The density decline in the envelope is significantly steeper than those obtained by Mouschovias and collaborators, who considered disklike magnetic clouds whose initial magnetic pressure is much larger than the thermal pressure. As the cloud density increases above approximately 105 cm-3, dust grains become dynamically important. Depending on their size distribution, dust grains can enhance the coupling coefficient between the magnetic field and the neutral cloud matter by as much as an order of magnitude or even more. The enhanced coupling makes it difficult for magnetic flux to escape during the advanced, more dynamic phase of the core formation. In spherical geometry, this trapping of magnetic flux leads to an almost homologous collapse of a central region with substantial mass. The implied extremely rapid assemblage of protostellar mass, with more than 0.5 M☉ of material reaching the origin in about 103 yr or less for a typical set of cloud parameters, poses a serious accretion "luminosity problem." Magnetic tension in two-dimensional models may help alleviate the problem.
Convex profiles from asteroid lightcurves

A lightcurve inversion method that yields a two-dimensional convex profile is introduced. The number of parameters that characterize the profile is limited only by the number of Fourier harmonics used to represent the parent lightcurve. The implementation of the method is outlined by a recursive quadratic programming algorithm, and its application to photoelectric lightcurves and radar measurements is discussed. Special properties of the lightcurves of geometrically scattering ellipsoids are pointed out, and those properties are used to test the inversion method and obtain a criterion for judging whether any lightcurve could actually be due to such an object. Convex profiles for several asteroids are shown, and the method's validity is discussed from a physical as well as purely statistical point of view.
Large-N QCD baryon dynamics: exact results from its relation to the static strong-coupling theory

Starting from the large-$N$ power counting which suggests that the baryons are QCD solitons, the authors derive an exact large-$N$ equation identical to the so-called bootstrap condition of static strong-coupling theory. This equation determines the group structure of the baryon multiplets at $N\ensuremath{\rightarrow}\ensuremath{\infty}$. One solution is the standard nonrelativistic quark model.
Inflows of Foreign Technology and Indigenous Technological Development

This paper explores the effects of inflows of foreign technology on technological development in developing countries. It evaluates the existing literature exploring this issue and indicates directions for further research. In particular, it is argued that the implications of the theory of foreign direct investment (the dominant channel of international technology transfer) for technological development have not been fully explored. Dynamic analyses of technology transfer that accommodate the salient features of developing countries have also begun to appear only recently. Further work along these lines is likely to yield rich dividends.
Distributed Object Location in a Dynamic Network

Modern networking applications replicate data and services widely, leading to a need for location-independent routing—the ability to route queries to objects using names independent of the objects’ physical locations. Two important properties of such a routing infrastructure are routing locality and rapid adaptation to arriving and departing nodes.We showhowthese two properties can be efficiently achieved for certain network topologies. To do this, we present a new distributed algorithm that can solve the nearest-neighbor problem for these networks. We describe our solution in the context of Tapestry, an overlay network infrastructure that employs techniques proposed by Plaxton et al. [24].
Optical Engineering Problems Associated With Construction Of The Shiva Laser Fusion Facility

AbstractThe Shiva laser system is part of a new 20 terawatt laser facility at Lawrence Livermore Laboratory. The system contains more than $5,000,000 worth of optics. This paper discusses the various optical components,typical-component quantities and specification, and the problem of laser damage to components.IntroductionThe Shiva laser is a twenty -arm Nd:glass laser fusion facility which is in the final phases of system activation. Figure 1 is a model of hi la er system. This system has been described extensively from bothan engineering and physics viewpointk1, ,3, , ); however, this paper will address some of the unique opticalproblems associated with a project of this size. The Shiva laser has been designed to focus more than20 terawatts (2x1013 W) of laser power onto a fusion target a few hundred microns in diameter. To achievethis power level requires twenty identical laser chains, each with an input aperture of 2.5 cm diameter anda final output aperture of 20 cm diameter. feilf,,..
State Dependence, Serial Correlation and Heterogeneity in Intertemporal Labor Force Participation of Married Women

A dynamic search framework is developed to analyze the intertemporal labor force participation behavior of married women, using longitudinal data to allow for a rich dynamic structure. The sensitivity to alternative distributional assumptions is evaluated using linear probability and probit models. The dynamic probit models are estimated using maximum simulated likelihood (MSL) estimation, to overcome the computational difficulties inherent in maximum likelihood estimation of models with nontrivial error structures. The results find that participation decisions are characterized by significant state dependence, unobserved heterogeneity, and negative serial correlation in the error component. The hypothesis that fertility decisions are exogenous to women's participation decisions is rejected when dynamics are ignored; however, there is no evidence against this hypothesis in dynamic model specifications. Women's participation response is stronger to permanent than current nonlabor income, reflecting unobserved taste factors.
The Higher Education of Gaming

New models of schooling are necessary as educational institutions attempt to transition into the digital age. This article is an ethnography of Apolyton University, an informal online university of gamers created to enhance pleasure from the game experience, teach the game, and improve upon the game's standard rule set. It identifies the life trajectory of the community from formation to completion, and identifies key participant structures that scaffold learning. The article argues that participation results in a trajectory of experience whereby players enter as players but leave as designers, as evidenced by gameplay practices, as well as several participants being hired by game companies as a result of their participation. The authors argue that this sort of participatory ethos is central to learning systems in a digital age.
An energy minimization approach to 3D non-rigid deformable surface estimation using RGBD data

We propose an algorithm that uses energy minimization to estimate the current configuration of a non-rigid object. Our approach utilizes an RGBD image to calculate corresponding SURF features, depth, and boundary information. We do not use predetermined features, thus enabling our system to operate on unmodified objects. Our approach relies on a 3D nonlinear energy minimization framework to solve for the configuration using a semi-implicit scheme. Results show various scenarios of dynamic posters and shirts in different configurations to illustrate the performance of the method. In particular, we show that our method is able to estimate the configuration of a textureless nonrigid object with no correspondences available.
Dehydrative Sialylation with C2-Hemiketal Sialyl Donors

[reaction: see text] A new method for sialylation involving the dehydrative coupling of sialyl donors with the reagent combination of (p-nitrophenyl)(phenyl) sulfoxide and triflic anhydride is reported. This process establishes sialyl C2-hemiketals as viable sialyl donors for complex carbohydrate synthesis.
Laser excitation of surface electronic states for a one-dimensional semiconductor

Abstract The electronic band structure of a finite one-dimensional semiconductor is examined. The surface states are identified and the absorption cross-section for transitions to these states is calculated. The use of a laser to enhance surface charge density is discussed.
VERTEX-IRF TRANSFORMATIONS AND QUANTIZATION OF DYNAMICAL r-MATRICES

Motivated by the correspondence between the vertex and IRF models in statistical mechanics, we define and study a notion of vertex-IRF transformation for dynamical twists that generalizes a usual gauge transforma- tion. We use vertex-IRF transformations to quantize all completely degenerate dynamical r-matrices on finite-dimensional Lie algebras.
Coherent image processing using quaternion wavelets

We develop a quaternion wavelet transform (QWT) as a new multiscale analysis tool for geometric image features. The QWT is a near shift-invariant, tight frame representation whose coefficients sport a magnitude and three phase values, two of which are directly proportional to local image shifts. The QWT can be efficiently computed using a dual-tree filter bank and is based on a 2-D Hilbert transform. We demonstrate how the QWT's magnitude and phase can be used to accurately analyze local geometric structure in images. We also develop a multiscale flow/motion estimation algorithm that computes a disparity flow map between two images with respect to local object motion.
A mechanistic model of the northern annular mode

[1] The northern annular mode (NAM) is the leading mode of variability in the Northern Hemisphere. The NAM consists of a meridional dipole of the zonal mean zonal wind that extends into the stratosphere during the winter season. During the high-index state of the NAM, high-latitude westerly winds are stronger than normal, leading to a stronger and colder polar vortex. Over the past few decades, observations show a trend toward higher NAM index values. To investigate whether this trend is a result of natural variability or is related to greenhouse warming, a mechanistic model is developed that provides a simple analogue of the NAM. The model represents the interaction between the zonally symmetric flow and planetary waves for two meridional modes of variation. Greenhouse warming is specified in the model by varying the radiative equilibrium meridional temperature gradient. Variations in the second meridional mode qualitatively resemble those of the observed NAM. Model runs that correspond to larger greenhouse gas concentrations yield on average higher NAM index values.
ATMOSPHERIC CIRCULATION OF ECCENTRIC HOT JUPITER HAT-P-2B

The hot Jupiter HAT-P-2b has become a prime target for Spitzer Space Telescope observations aimed at understanding the atmospheric response of exoplanets on highly eccentric orbits. Here we present a suite of three-dimensional atmospheric circulation models for HAT-P-2b that investigate the effects of assumed atmospheric composition and rotation rate on global scale winds and thermal patterns. We compare and contrast atmospheric models for HAT-P-2b, which assume one and five times solar metallicity, both with and without TiO/VO as atmospheric constituents. Additionally we compare models that assume a rotation period of half, one, and two times the nominal pseudo-synchronous rotation period. We find that changes in assumed atmospheric metallicity and rotation rate do not significantly affect model predictions of the planetary flux as a function of orbital phase. However, models in which TiO/VO are present in the atmosphere develop a transient temperature inversion between the transit and secondary eclipse events that results in significant variations in the timing and magnitude of the peak of the planetary flux compared with models in which TiO/VO are omitted from the opacity tables. We find that no one single atmospheric model can reproduce the recently observed full orbit phase curves at 3.6, 4.5 and 8.0 μm, which is likely due to a chemical process not captured by our current atmospheric models for HAT-P-2b. Further modeling and observational efforts focused on understanding the chemistry of HAT-P-2b's atmosphere are needed and could provide key insights into the interplay between radiative, dynamical, and chemical processes in a wide range of exoplanet atmospheres.
Advanced instrumentation for next-generation aerospace propulsion control systems

New control concepts for the next generation of advanced air-breathing and rocket engines and hypersonic combined-cycle propulsion systems are analyzed. The analysis provides a database on the instrumentation technologies for advanced control systems and cross matches the available technologies for each type of engine to the control needs and applications of the other two types of engines. Measurement technologies that are considered to be ready for implementation include optical surface temperature sensors, an isotope wear detector, a brushless torquemeter, a fiberoptic deflectometer, an optical absorption leak detector, the nonintrusive speed sensor, and an ultrasonic triducer. It is concluded that all 30 advanced instrumentation technologies considered can be recommended for further development to meet need of the next generation of jet-, rocket-, and hypersonic-engine control systems.
Management of primary immune thrombocytopenia, 2012: a survey of oklahoma hematologists-oncologists.

Abstract Background Management options for patients with primary immune thrombocytopenia (ITP) have increased, and treatment of patients with ITP has changed during the past 10 years. Methods To document current practice and to determine how current practice is related to recommendations of 2 recent practice guidelines for ITP, an international Consensus report and an American society of Hematology (ASH) guideline, the authors surveyed practicing hematologistsoncologists in Oklahoma. Surveys were specific for children or adults. Each survey had 3 questions describing patients with a new diagnosis and patients who had not achieved remission with initial treatment. Questions were adapted from the clinical scenarios of the ASH guideline. Results Twelve (92%) Oklahoma pediatric hematologistsoncologists responded; 82 (81%) Oklahoma adult hematologistsoncologists responded. For a child with a new diagnosis of ITP, a platelet count of 8000/μL and minor bleeding, 5 (42%) hematologistsoncologists selected observation without drug treatment (recommended by both guidelines). For an adult with a platelet count of 9000/μL who had failed to respond to initial treatment with corticosteroids and IVIg, 32 (39%) selected splenectomy (recommended by the ASH guideline); 30 (37%) selected rituximab and 13 (16%) selected thrombopoietin-receptor agonists (both recommended by the International Consensus report). Hematologists-oncologists who had more years in practice were more likely to select splenectomy ( P = 0.047). Conclusions In a time of changing management for patients with ITP, these data document reported current management in Oklahoma and provide a basis for serial comparisons across time and for comparisons with other regions and comparison of management with patient outcomes.
Discrete Time Quantum Mechanics

Abstract This paper summarizes a research program that has been underway for a decade. The objective is to find a fast and accurate scheme for solving quantum problems which does not involve a Monte Carlo algorithm. We use an alternative strategy based on the method of finite elements. We are able to formulate fully consistent quantum-mechanical systems directly on a lattice in terms of operator difference equations. One advantage of this discretized formulation of quantum mechanics is that the ambiguities associated with operator ordering are eliminated. Furthermore, the scheme provides an easy way in which to obtain the energy levels of the theory numerically. A generalized version of this discretization scheme can be applied to quantum field theory problems. The difficulties normally associated with fermion doubling are eliminated. Also, one can incorporate local gauge invariance in the finite-element formulation. Results for some field theory models are summarized. In particular, we review the calculation of the anomaly in two-dimensional quantum electrodynamics (the Schwinger model). Finally, we discuss nonabelian gauge theories.
computer aided intuition in abstract algebra

Abstract Two examples are given in which the computer was used to supplement intuition in abstract algebra. In the first example, the computer was used to search Cayley tables of 4 element groupoids to find those which are 5-associative but not 4-associative. ( n-associative means that the product of any n elements is independent of the way the factors are grouped by parentheses.) The computer generated examples suggested the existence of n element groupoids which are (2 n −2 +1)-associative but not (2 n -2 )-associative, for each integer n ≧4. In the second example, the computer counted the numbers g 2 ( m ) of invertible 2×2 matrices with entries chosen from the ring Z m of integers, for m = 2, 3, 4,…, 18. The insight gained from these results led to a proof that there are ɡ n (m) (n 2 ) ∏ p m (1−p −1 )⋯(1−p −n ) invertible n × n matrices over Z m . Some applications to graduate and undergraduate instruction are indicated.
Leachability of uranium and other elements from freshly erupted volcanic ash

Abstract A study of leaching of freshly erupted basaltic and dacitic air-fall ash and bomb fragment samples, unaffected by rain, shows that glass dissolution is the dominant process by which uranium is initially mobilized from air-fall volcanic ash. Si, Li, and V are also preferentially mobilized by glass dissolution. Gaseous transfer followed by fixation of soluble uranium species on volcanic-ash particles is not an important process affecting uranium mobility. Gaseous transfer, however, may be important in forming water-soluble phases, adsorbed to ash surfaces, enriched in the economically and environmentally important elements Zn, Cu, Cd, Pb, B, F, and Ba. Quick removal of these adsorbed elements by the first exposure of freshly erupted ash to rain and surface water may pose short-term hazards to certain forms of aquatic and terrestrial life. Such rapid release of material may also represent the first step in transportation of economically important elements to environments favorable for precipitation into deposits of commercial interest. Ash samples collected from the active Guatemalan volcanoes Fuego and Pacaya (high-Al basalts) and Santiaguito (hornblende-hypersthene dacite); bomb fragments from Augustine volcano (andesite-dacite), Alaska, and Heimaey (basalt), Vestmann Islands, Iceland; and fragments of “rhyolitic” pumice from various historic eruptions were subjected to three successive leaches with a constant water-to-ash weight ratio of 4:1. The volcanic material was successively leached by: (1) distilled-deionized water (pH = 5.0–5.5) at room temperature for 24 h, which removes water-soluble gases and salts adsorbed on ash surfaces during eruption; (2) dilute HCl solution (pH = 3.5–4.0) at room temperature for 24 h, which continues the attack initiated by the water and also attacks acid-soluble sulfides and oxides; (3) a solution 0.05 M in both Na,CO, and NaHCO, (pH = 9.9) at 80°C for one week, which preferentially dissolves volcanic glass. The first two leaches mimic interaction of ash with rain produced in the vicinity of an active eruption. The third leach accelerates the effect of prolonged contact of volcanic ash with alkaline ground water present during ash diagenesis.
Factorization for Hadronic Heavy Quarkonium Production

We briefly review several models of heavy quarkonium production in hadronic collisions, and discuss the status of QCD factorization for these production models.
Death by polonium-210: lessons learned from the murder of former Soviet spy Alexander Litvinenko

The medical response to radiation—whether the result of radiological warfare, terrorist deployment of improvised radiation dispersal weapons, political assassination, occupational or industrial accidents or the medically radiated patient remains one of the least taught among all disciplines within medical education. In the aftermath of 9/11 among medical vulnerabilities to toxicant threats, of all the categories of weapons of mass destruction (WMD)—whether using the CBRNE (chemical, biological, radiological, nuclear, explosive) or NBC (nuclear, biological, chemical) acronym—radiation is the least taught in professional schools, responder cultures or civil preparedness organizations. To date, few health care professionals (HCP) possess the fundamental knowledge or skills to identify and diagnose, let alone treat a radiation victim; this vulnerability made even more obvious in the aftermath of the high profile assassination of former Russian agent Alexander Litvinenko. He was poisoned with Polonium 210 . Radioactive substances are ubiquitous with radiation sources being in or transported through virtually every region nationwide. It is essential to increase preparedness among community and rural health care facilities as well as urban and university hospitals. Managing radiation injuries effectively requires access to specialized equipment and expertise. Radiation sickness is progressive and may require acute, critical and long term care throughout the course of illness. Regardless of the source, preparedness rests upon acknowledging a threat exists and dedicating the resources to address the risks including the enhancement of training and equipment. Mass or individual exposures to radiation present unique challenges to the entire response continuum from law enforcement, first responders and emergency medical care. Increased education about and practice in responding to radiological threats is essential to enhance preparedness.
On the speed of a planar random walk avoiding its past convex hull

Abstract We consider a random walk in R 2 which takes steps uniformly distributed on the unit circle centered around the walker's current position but avoids the convex hull of its past positions. This model has been introduced and studied by Angel, Benjamini and Virag. We show a large deviation estimate for the distance of the walker from the origin, which implies that the walker has positive lim inf speed.
Implications of shear heating and fracture zones for ridge formation on Europa

[1] We present 2D and 3D numerical simulations of convection to test the role of shear heating and fracture zones on Europan ridge formation. Our simulations show that a pre-existing fracture zone promotes upwelling and lithospheric thinning, leading to topographic uplift of 50 m. Shear heating also promotes lithospheric thinning and buoyant ascent, producing a ridge-like feature with topography up to 120 m. Topography remains linear along strike even under the influence of heterogeneous 3D convection within the ice shell. Although the central trough is not reproduced in the simulations, our results support the idea that shear heating can produce ridge-like structures on Europa.
Stereoselective Synthesis of Conjugated Fluoro Enynes

Metalation–electrophilic fluorination of TMS- and TIPS-protected 1,3-benzothiazol-2-yl (BT) propargyl sulfones gave corresponding BT fluoropropargyl sulfones, Julia–Kocienski reagents for the synthesis of fluoro enynes. Both reagents reacted with aldehydes under mild DBU- or LHMDS-mediated conditions, giving high yields of conjugated fluoro enynes with E-stereoselectivity. In comparison to DBU-mediated reactions, stereoselectivity was higher in low-temperature LHMDS-mediated reactions. Two ketones were shown to react as well, using LHMDS as base. In situ removal of the TMS group gave terminal conjugated 2-fluoro 1,3-enynes. Synthetic utility of the fluoro enynes was demonstrated by conversion to internal alkynes and to stereoisomeric fluoro dienes via Sonogashira and Heck couplings.
Flow visualization and heat transfer experiments in fluid-superposed packed beds heated from below

Abstract Flow visualization and heat transfer experiments are reported for buoyancy-induced flow in a cylindrical cavity filled with a fluid-superposed packed bed and heated from below. An immersion method is used to measure the refractive index of acrylic spheres, which is then matched with that of the silicon fluid. This allows visualization of interesting flow interactions between the porous bed and overlying fluid. Flow channels through large voids produce highly asymmetric and complicated flow structures, and the number of convective rolls depends on the porous layer height η. The heat transfer rate increases with the Rayleigh number Ra∗, but the dependence on the particle size γ and the porous bed height is very complex. The average Nusselt number generally increases with the solid-bead diameter, but there may exist some values of η for which the heat transfer rate for a smaller particle size in higher than that for a larger value of γ. Also, the Nusselt number first decreases from the fluid heat transfer rates with an increase in porous matrix height η and reaches a minimum at η min. Any further increase in porous layer height beyond ηmin augments the heat transfer rate, and the Nusselt number curves show peaks at ηmin
Stochastic ion heating at the magnetopause due to kinetic Alfvén waves

The magnetopause and boundary layer are typically characterized by large amplitude transverse wave activity with frequency below the ion cyclotron frequency. The signatures of the transverse waves suggest that they are kinetic Alfven waves with wavelength on the order of the ion gyroradius. We investigate ion motion in the presence of large amplitude kinetic Alfven waves with wavelength the order of rho(subscript ''i'') and demonstrate that for sufficiently large wave amplitude (delta B(subscript ''perpendicular'')/B(subscript ''0'') > 0.05) the particle orbits become stochastic. As a result, low energy particles in the core of the ion distribution can migrate to higher energy through the stochastic sea leading to an increase in T(subscript ''perpendicular'') and a broadening of the distribution. This process can explain transverse ion energization and formation of conics which have been observed in the low-latitude boundary layer.
Proton decay in intersecting D-brane models

Abstract We analyze proton decay via dimension-six operators in certain GUT-like models derived from Type IIA orientifolds with D6-branes. The amplitude is parametrically enhanced by a factor of α GUT −1/3 relative to the corresponding result in four-dimensional GUTs. Nonetheless, even assuming a plausible enhancement from the threshold corrections, we find little overall enhancement of the proton decay rate from dimension-six operators, so that the predicted lifetime from this mechanism remains close to 10 36 years.
Computational fluid dynamics modeling for emergency preparedness and response

Abstract This paper reviews the influence of computational fluid dynamics in the improvement of atmospheric dispersion models. Some of the factors that led to the widespread use of this computational approach include the availability of affordable high-performance workstations, the sharing of data via the information superhighway and the advances in the development of computational algorithms. While the traditional role of computational fluid dynamics has been to provide wind fields for dispersion models, recent new applications have emerged wherein prognostic forecast models were used to provide responses to weather-related emergencies on both local as well as regional scales.
Convergence in the activities of European banks

Abstract Cross-country integration of banking in Europe typically has been analyzed from the perspective of particular markets for financial products. We extend this research to consider the potential effects of market integration on the portfolio choices and financial structure of banks in seven European countries, 1994–2002. Our evidence rejects a hypothesis that banks in different countries have common activities. Distinct portfolio choices are more evident among small banks, as opposed to big banks, are more evident in Italy and are less evident in the UK and Spain. We conclude that integration of financial markets in Europe, to the extent that it has occurred, has not imposed a uniform mix of activities on European banks.
Large-eddy simulation of stably stratified atmospheric boundary layer turbulence: A scale-dependent dynamic modeling approach

Abstract A new tuning-free subgrid-scale model, termed locally averaged scale-dependent dynamic (LASDD) model, is developed and implemented in large-eddy simulations (LES) of stable boundary layers. The new model dynamically computes the Smagorinsky coefficient and the subgrid-scale Prandtl number based on the local dynamics of the resolved velocity and temperature fields. Overall, the agreement between the statistics of the LES-generated turbulence and some well-established empirical formulations and theoretical predictions (e.g., the local scaling hypothesis) is remarkable. Moreover, the simulated statistics obtained with the LASDD model show relatively little resolution dependence for the range of grid sizes considered here. In essence, it is shown here that the new LASDD model is a robust subgrid-scale parameterization for reliable, tuning-free simulations of stable boundary layers, even with relatively coarse resolutions.
Viscoelastic properties of dilute polymer solutions

Abstract The frequency dependences of the intrinsic storage and loss shear moduli can be predicted from molecular theories for flexible random coil polymers (bead-spring models) and for rigid elongated macromolecules. Comparison with various experimental data extrapolated to infinite dilution shows good agreement with both these extreme types. For semi-rigid helical macromolecules, and for highly charged polyelectrolytes, experimental data correspond to hybrid relaxation spectra which are attributed to rigid-body rotation together with certain internal motions – probably flexural modes for the helices, configurational rearrangements for the polyelectrolytes. At high frequencies or in high-viscosity solvents, additional energy dissipation mechanisms appear in random coil polymers, whose nature is still conjectural.
Sideband instabilities and defects of quasipatterns

Abstract Quasipatterns have been found in dissipative systems ranging from Faraday waves in vertically vibrated fluid layers to nonlinear optics. We describe the dynamics of octagonal, decagonal and dodecagonal quasipatterns by means of coupled Ginzburg–Landau equations and study their stability to sideband perturbations analytically using long-wave equations as well as by direct numerical simulation. Of particular interest is the influence of the phason modes, which are associated with the quasiperiodicity, on the stability of the patterns. In the dodecagonal case, in contrast to the octagonal and the decagonal case, the phase modes and the phason modes decouple and there are parameter regimes in which the quasipattern first becomes unstable with respect to phason modes rather than phase modes. We also discuss the different types of defects that can arise in each kind of quasipattern as well as their dynamics and interactions. Particularly interesting is the decagonal quasipattern, which allows two different types of defects. Their mutual interaction can be extremely weak even at small distances.
Nucleosynthesis, Reionization, and the Mass Function of the First Stars

We critique the hypothesis that the first stars were very massive stars (VMSs; M > 140 M☉). We review the two major lines of evidence for the existence of VMSs: (1) that the relative metal abundances of extremely metal-poor Galactic halo stars show evidence of VMS enrichment and (2) that the high electron-scattering optical depth (τe) to the cosmic microwave background found by the Wilkinson Microwave Anisotropy Probe (WMAP) requires VMSs for reionization in a concordance ΛCDM cosmology. The yield patterns of VMSs exploding as pair-instability supernovae are incompatible with the Fe-peak and r-process abundances in halo stars. Models including Type II supernovae and/or "hypernovae" from zero-metallicity progenitors with M = 8-40 M☉ can better explain the observed trends. We use the nucleosynthesis results and stellar evolution models to construct an initial mass function (IMF) for reionization. With a simple metal transport model, we estimate that halo enrichment curtails metal-free star formation after ~108 yr at z ~ 20. Because the lifetime-integrated ionizing photon efficiency of metal-free stars peaks at ~120 M☉ and declines at higher mass, an IMF with an approximate lower bound at M ~ 10-20 M☉ and no VMS can maximize the ionizing photon budget and still be consistent with the nucleosynthetic evidence. An IMF devoid of low-mass stars is justified independently by models of the formation of primordial stars. Using a semianalytic model for H I and He II reionization, we find that such an IMF can reproduce τe 0.10-0.14, consistent with the range from WMAP, without extreme astrophysical assumptions, provided that metal-free star formation persists 107-108 yr after star formation begins. Because stars in the mass range 50-140 M☉ are the most efficient sources of ionizing photons but are expected to collapse to black holes without releasing metals, this IMF effectively decouples early metal enrichment and early ionization. Such an IMF may allow the unique properties of the zero-metallicity IMF to persist longer than they would in the pure VMS case and to contribute significantly to the global ionizing photon budget before halo self-enrichment and/or interhalo metal transport truncates metal-free star formation. We conclude, on the basis of these results, that VMSs are not necessary to meet the existing constraints commonly taken to motivate them.
Charmonium spectroscopy - A review

Abstract A review is presented of the latest developments in the spectroscopy of charmonium.
Synthesis of bistramide A.

We have developed an efficient and highly stereocontrolled synthesis of bistramide A, a selective activator of protein kinase C isotype δ. Our synthetic strategy featured a novel bidirectional approach for spiroketal construction based on the ring-opening/cross-metathesis sequence employing a highly strained cyclopropenone acetal. The synthesis afforded the final target with the longest linear sequence of 15 steps and provided unambiguous structural determination of bistramide A, including assignment of the previously unknown C37 stereochemistry.
American universities and technical advance in industry

Abstract Over the past decade there has been an intensification of interest in how universities can play a more effective role in promoting technical advance in American industry. However, very little of the current discussion is solidly based on an informed analysis of the roles that universities actually play today or the historical circumstances that caused universities to assume these roles. This paper offers an analysis, both historical and contemporary, that identifies the distinctive strengths, as well as limitations, of university research. Regarding the strengths, most of university research is basic research in the sense that it aims to understand phenomena at a relatively fundamental level. However, this does not mean that such research is uninfluenced by the pull of important technological problems and objectives. The lion's share of university research is in the engineering disciplines and applied sciences such as computer science and oncology which, by their nature, are oriented toward problem-solving. Despite its obvious usefulness, industry does very little of such basic research because the payoffs are of a long-run nature as well as difficult to appropriate. The vast bulk of industry R&D is focused directly on shorter term problem-solving, design and development. Universities are not particularly good at this sort of work. Industry is more effective in dealing with problems that are located close to the market place. This paper argues that new policies will need to respect this division of labor.
Effective information system security with password controls

Abstract Password systems are a first line of defense that can prevent, deter, and detect abusive acts. They are one of the most cost effective computer resource control mechanisms presently available. This piece explores some of the more salient aspects of password system design, including objectives of password controls, design philosophies, man-machine interface design, system administration, and technical system implementation.
How quantum bound states bounce and the structure it reveals

We investigate how quantum bound states bounce from a hard surface. Our analysis has applications to ab initio calculations of nuclear structure and elastic deformation, energy levels of excitons in semiconductor quantum dots and wells, and cold atomic few-body systems on optical lattices with sharp boundaries. We develop the general theory of elastic reflection for a composite body from a hard wall. On the numerical side we present ab initio calculations for the compression of alpha particles and universal results for two-body states. On the analytical side we derive a universal effective potential that gives the reflection scattering length for shallow two-body states.
The Kobayashi metric in the normal direction and the mapping problem

Estimates of the Kobayashi metric in the normal direction are used to study the mapping problem in several complex variables.
The radiation of sound from a propeller at angle of attack

The mechanism by which the noise generated at the blade passing frequency by a propeller is altered when the propeller axis is at an angle of attack to the freestream is examined. The measured noise field is distinctly non axially symmetric under such conditions with far field sound pressure levels both diminished and increased relative to the axially symmetric values produced with the propeller at zero angle of attack. Attempts have been made to explain this non axially symmetric sound field based on the unsteady (once per rev) loading experienced by the propeller blades when the propeller axis is at non zero angle of attack. A calculation based on this notion appears to greatly underestimate the measured azimuthal asymmetry of noise for high tip speed, highly loaded propellers. A new mechanism is proposed; namely, that at angle of attack, there is a non axially symmetric modulation of the radiative efficiency of the steady loading and thickness noise which is the primary cause of the non axially symmetric sound field at angle of attack for high tip speed, heavily loaded propellers with a large number of blades. A calculation of this effect to first order in the crossflow Mach number (component of freestream Mach number normal to the propeller axis) is carried out and shows much better agreement with measured noise data on the angle of attack effect.
ASPECTS OF THE RIEMANNIAN GEOMETRY OF QUANTUM COMPUTATION

A review is given of some aspects of the Riemannian geometry of quantum computation in which the quantum evolution is represented in the tangent space manifold of the special unitary unimodular group SU(2n) for n qubits. The Riemannian right-invariant metric, connection, curvature, geodesic equation for minimal complexity quantum circuits, Jacobi equation and the lifted Jacobi equation for varying penalty parameter are reviewed. Sharpened tools for calculating the geodesic derivative are presented. The geodesic derivative may facilitate the numerical investigation of conjugate points and the global characteristics of geodesic paths in the group manifold, the determination of optimal quantum circuits for carrying out a quantum computation, and the determination of the complexity of particular quantum algorithms.
*-Quantizations of Fourier-Mukai transforms

We study deformations of Fourier–Mukai transforms in general complex analytic settings. Suppose X and Y are complex manifolds, and let P be a coherent sheaf on X × Y. Suppose that the Fourier–Mukai transform \({\Phi}\) given by the kernel P is an equivalence between the coherent derived categories of X and of Y. Suppose also that we are given a formal *-quantization \({\mathbb{X}}\) of X. Our main result is that \({\mathbb{X}}\) gives rise to a unique formal *-quantization \({\mathbb{Y}}\) of Y. For the statement to hold, *-quantizations must be understood in the framework of stacks of algebroids. The quantization \({\mathbb{Y}}\) is uniquely determined by the condition that \({\Phi}\) deforms to an equivalence between the derived categories of \({\mathbb{X}}\) and \({\mathbb{Y}}\) . Equivalently, the condition is that P deforms to a coherent sheaf \({\tilde{P}}\) on the formal *-quantization \({\mathbb{X} \times\mathbb{Y}^{op}}\) of X × Y; here \({\mathbb{Y}^{op}}\) is the opposite of the quantization \({\mathbb{Y}}\) .
QUILT: a GUI-based integrated circuit floorplanning environment for computer architecture research and education

In this paper, we describe a graphic editing tool called QUILT (Quick Utility for Integrated circuit Layout and Temperature modeling). QUILT permits users to rapidly build floorplans of integrated circuits, providing both a visual aid as well as an input to the HotSpot simulator. The tool provides numerous features for estimating circuit performance, such as interconnect delay, and for generating graphical images for publications. As a graphical and easy to use tool, QUILT is well suited for both research and coursework purposes.
A Simple Analytic Treatment of the Intergalactic Absorption Effect in Blazar Gamma-Ray Spectra

We derive a new and user-friendly simple analytic approximation for determining the effect of intergalactic absorption on the γ-ray spectra of TeV blazars in the energy range 0.2 TeV < Eγ < 2 TeV and in the redshift range 0.05 < z < 0.4. In these ranges, the form of the absorption coefficient τ(Eγ) is approximately logarithmic. The effect of this energy dependence is to steepen intrinsic source spectra such that a source with an approximate power-law spectral index Γs is converted to one with an observed spectral index Γo Γs + ΔΓ(z), where ΔΓ(z) is a linear function of z in the redshift range 0.05-0.4. We apply this approximation to the spectra of seven TeV blazars.
Experimental Investigation of Mode Localization and Forced Response Amplitude Magnification for a Mistuned Bladed Disk

The results of an experimental investigation on the effects of random blade mistuning on the forced dynamic response of bladed disks are reported. The primary aim of the experiment is to gain understanding of the phenomena of mode localization and forced response blade amplitude magnification in bladed disks. A stationary, nominally periodic, 12-bladed disk with simple geometry is subjected to a traveling-wave out-of-plane engine order excitation delivered via phase-shifted control signals sent to piezoelectric actuators mounted on the blades. The bladed disk is then mistuned by the addition of small. unequal weights to the blade tips, and it is again subjected to a traveling wave excitation. The experimental data is used to verify analytical predictions about the occurrence of localized mode shapes, increases in forced response amplitude, and changes in resonant frequency due to the presence of mistuning. Very good agreement between experimental measurements and finite element analysis is obtained. The out-of-plane response is compared and contrasted with the previously reported in-plane mode localization behavior of the same test specimen. This work also represents an important extension of previous experimental study by investigating a frequency regime in which modal density is lower but disk-blade interaction is significantly greater.
Seasonal and Energy Dependence of Solar Neutrino Vacuum Oscillations

Abstract We make a global vacuum neutrino oscillation analysis of solar neutrino data, including the seasonal and energy dependence of the recent Super-Kamiokande 708-day results. The best fit parameters for ν e oscillations to an active neutrino are δm 2 =4.42×10 −10 eV 2 , sin 2 2 θ =0.93. The allowed mixing angle region is consistent with bi-maximal mixing of three neutrinos. Oscillations to a sterile neutrino are disfavored. Allowing an enhanced hep neutrino flux does not significantly alter the oscillation parameters.
Electrochromic lithium nickel oxide by pulsed laser deposition and sputtering

Abstract Thin films of lithium nickel oxide were deposited by sputtering and pulsed laser deposition (PLD) from targets of pressed LiNiO2 powder. The composition and structure of these films were analyzed using a variety of techniques, such as nuclear-reaction analysis, Rutherford backscattering spectrometry (RBS), X-ray diffraction, infrared spectroscopy, and atomic-force microscopy. Crystalline structure, surface morphology and chemical composition of LixNi1−xO thin films depend strongly on deposition oxygen pressure, temperature as well as substrate–target distance. The films produced at temperatures lower than 600°C spontaneously absorb CO2 and H2O at their surface once they are exposed to the air. The films deposited at 600°C proved to be stable in air over a long period. Even at room temperature the PLD films are denser and more stable than sputtered films. RBS determined the composition of the best films to be Li0.5Ni0.5O deposited by PLD at 60 mTorr O2 pressure. Electrochemical tests show that the films exhibit excellent reversibility in the range 1.0–3.4 V versus lithium. Electrochemical formatting which is used to develop electrochromism in other films is not needed for the stoichiometric films. The optical transmission range is almost 70% at 550 nm for 150 nm-thick films. Devices made from these films were analyzed using novel reference electrodes and by disassembling after cycling.
Post's problem for supertasks has both positive and negative solutions

The infinite time Turing machine analogue of Post's problem, the question whether there are semi-decidable supertask degrees between 0 and the supertask jump 0∇, has in a sense both positive and negative solutions. Namely, in the context of the reals there are no degrees between 0 and 0∇, but in the context of sets of reals, there are; indeed, there are incomparable semi-decidable supertask degrees. Both arguments employ a kind of transfinite-injury construction which generalizes canonically to oracles.