cssi/SciSciGPT-SciSciNet huggingface dataset:
A local transient approach to monitoring fluidization quality in freely bubbling beds

In fluidization processes, the optimal contacting regime is dictated by the physical or chemical process in question, and can vary significantly from application to application. Even within the specified regime, it is often necessary to place constraints on the hydrodynamic behavior in order to meet operational requirements. While the ability to do this is very important, there is a lack in current technologies' ability to identify the operational state via direct measurement. This work adopts a local transient approach towards addressing this problem. In order to study the local fluid bed dynamics, needle-type capacitance probes were employed to gather local transient solids fraction data in a bench-scale bubbling bed. The time-series were then subject to analysis in order to extract various signal invariants. The parametric effects of axial measurement location, superficial gas velocity, and mean particle size were examined in order to identify favorable heuristic trends in the signal invariants with respect to global parameters governing fluidization quality (i.e., superficial gas velocity and mean particle size). This work demonstrates how these invariants then constitute the basis for a novel regime map based monitoring scheme for quality of fluidization with potential application to feedback control.
Development of an air-coupled ultrasonic sensor for high-pressure and temperature applications

The focus of this investigation is to develop an Ultrasonic Position Indication System (UPIS) that is capable of determining one-dimensional target location in a steel- contained pressurized gaseous medium. The combination of the very high acoustical impedance of steel (45.4 MRay1) and the very low impedance of air (0.0004MRay1) causes extremely high- energy losses upon transmission. In addition to the energy loss, propagation through a steel plate produces many internal reflections in the plate. The strategy of this investigation is to develop a self-contained ultrasonic transducer that is capable of replacing a small portion of a high temperature- pressure boundary. In building such a transducer, sufficient acoustic matching layers for the steel-gas interface, a mechanically and acoustically competent housing, a sufficient piezoelectric element, and backing materials are all developed and tested. The results include a successful housing design, high-temperature acoustic matching layers, and subsequent successful waveforms. Target location through 9.6'(24.5 cm) of ambient air was successful, with a steel pressure boundary 0.4566' (1.1598 cm) thick, and using one matching layer.
Software tools and environments

Any system that assists the program-mer with some aspect of programmingcan be considered a programming tool.Similarly,asystemthatassistsinsomephaseofthesoftwaredevelopmentpro-cesscanbeconsideredasoftwaretool.Aprogrammingenvironmentisasuiteofprogrammingtoolsdesignedtosimplifyprogrammingandtherebyenhancepro-grammerproductivity.Asoftwareengi-neering environment extends this tosoftware tools and the whole softwaredevelopmentprocess.Softwaretoolsarecategorizedbythephaseofsoftwaredevelopmentandtheparticular problems that they address.Software environments are character-izedbythetypeandkindsoftoolstheycontainandthustheaspectsofsoftwaredevelopmenttheyaddress.Additionally,software environments are distin-guished by how the tools they includearerelated,thatis,thetypeanddegreeof integration among the tools, and bythesizeandnatureofthesystemstheyaredesignedtoaddress.Software tools and environments aredesignedtoenhanceproductivity.Manytools do this directly by automating orsimplifyingsometask.Othersdoitindi-rectly, either by facilitating more pow-erfulprogramminglanguages,architec-tures, or systems, or by making thesoftwaredevelopmenttaskmoreenjoy-able. Still others attempt to enhanceproductivitybyprovidingtheuserwithinformation that might be needed forthetaskathand.
Optical guiding in a free electron laser

Abstract The coherent interaction between an optical wave and an electron beam in a free electron laser (FEL) is shown to be capable of optically guiding the light. The effect is analyzed using a two-dimensional approximation for the FEL equations, and using the properties of optical fibers. Results of two-dimensional (cylindrically symmetric) numerical simulations are presented, and found to agree reasonably well with the analytically derived criterion for guiding. Under proper conditions, the effect can be large and has important applications to short wavelength FELs and to directing intense light.
Role of intra-adsorbate Coulomb correlations in energy transfer at metal surfaces

We present and discuss a theory of electronic friction for open-shell atomic or molecular adsorbates moving normal to a metallic surface. The theory applies to the case where the intra-adsorbate Coulomb interaction splits the positive- and negative-ion peaks in the spectral density of the adsorbate by an amount larger than their widths, and where one of them is much nearer the Fermi level than the other. We distinguish two limits: (i) the low-temperature friction regime where the friction is caused by the overlap of the adsorbate level's width and the Fermi level, and (ii) the high-temperature friction regime, where the friction is caused by thermally induced transitions. In regime (i) we find a large enhancement in the friction in many cases due to the Kondo effect, which can occur even at very high temperatures. In this region, the frictional force is highly temperature and velocity dependent. In region (ii), on the other hand, we typically find a reduction in the friction, sometimes substantial, from what is found in the traditional theory. Our results should be applicable to the description of desorption induced by hot electrons, which has been called DIMET when in region (ii).
The dynamical heliosphere

[1] The solar cycle induces substantial changes in the solar wind, which can have an important effect on the structure of the global heliosphere. In the ecliptic the ram pressure can vary from one cycle to the other, being greater during periods of minimum activity. We investigate the response of the heliosphere to a temporally varying solar wind. Since neutral hydrogen is a key component in determining the large-scale structure of the heliosphere, we employ a multifluid model in which the charge-exchange interaction between neutral hydrogen and protons is included self-consistently. The variability of the termination shock location is described and the response of the hydrogen wall to the temporal solar wind is discussed. Both two-shock and one-shock models are considered. The propagation of global shock waves analogous to those driven by global merged interactions (GMIR) is considered too for both one- and two-shock models. The global response of the heliosphere to a single GMIR disturbance can last for nearly a solar cycle (∼9.5 years). As a result of both a variable solar cycle ram pressure and the presence of disturbances of global extent, such as GMIRs, the large-scale heliosphere is most likely highly time-dependent and dynamical.
Diffusion Induced Bubble Populations Downstream of a Partial Cavity

Bubble populations downstream of stable partial cavities were examined using in-line holography, and the bubble number distribution and void fraction of the bubbly clouds were determined. The measured flux of bubbles downstream of the cavity was used to determine the diffusion rate of noncondensable gas into the cavity. Four models of gas diffusion into partial cavities from Parkin and Kermeen (1963), Brennen (1969), and Parkin and Ravindra (1993) are reviewed, and their predictions are compared with the experimentally determined mass diffusion rates. The models, which recognize a turbulent boundary layer over the cavity interface, over-predict the diffusion rate by one order of magnitude for cavities characterized by L/δ > 25.
Classification Systems with a Plot: Vessel Forms and Ceramic Typologies in the Spanish Atlantic

The majority of current Spanish ceramics studies rely heavily on a typology based on sherds from American excavations and museum collections. While decades of use and refinement have made this system invaluable for dating sites and recognizing trade patterns in the Americas, its focus on archaeological ceramic types does little to explain how individuals used and perceived their ceramics. I argue that using a vessel-based classification system will allow archaeologists to explore deeper questions regarding behavior and emic (user-ascribed) views of the objects recovered in excavations as well as provide a way of comparing Spanish and Spanish-American ceramic assemblages.
Knowledge shifts and the business cycle: When boom turns to bust

Informational cascades can be used to augment the existing Austrian business cycle theory. As first-order users of knowledge know the direct causes of a price change, they transmit this knowledge to second-order users through the price system. Banks with direct knowledge of the sources of the fresh liquidity during a credit-induced boom have knowledge of the boom’s artificial and unsustainable nature. Higher order users lack this direct knowledge and hence continue investing largely ignorant of underlying developments. When first-order users of knowledge sense the boom has run its course, they exit the market, sending a strong signal to higher order knowledge users that the boom has ended—a fragile situation built upon an informational cascade begins collapsing. Simultaneously, the boom is characterized by an influx of capital and knowledge into the financial sector owing to increased profits relative to the real economy stemming from Cantillon effects surrounding the credit injection. As knowledge pertaining to real production has also exited, the bust commences with a misallocated productive structure requiring equilibration to become consistent with consumers’ wants. Actions which inhibit this knowledge from returning to the productive structure will unnecessarily lengthen the time to recovery.
Regioselectivity and the role of olefin co-ordination in rhodium(I)-catalysed rearrangement of vinylcyclopropanes

Rearrangement of syn- and anti-7-vinylbicyclo-[4.1.0]heptanes in the presence of di-µ-chloro-tetra-carbonyldirhodium(I) exhibits kinetic behaviour and product selectivity which provide good evidence for initial co-ordination of the vinyl group and stereospecific cis-β-hydride elimination from a subsequent metallocyclic intermediate.
Models of high velocity impact phenomena

Abstract Models of craters formed by impacts at velocities of up to 24.5 km/sec have been computed using the Smooth Particle Hydrodynamics, MESA, EPIC and CALE codes. These modeling efforts are compared to data obtained from the Hypervelocity Microparticle Impact project at Los Alamos using the van de Graaff accelerator. A factor of 5 increase in yield strength was needed to account for high strain rate effects and to match the data. Structure in the data is addressed by using crater volume instead of crater diameter cubed. Detailed code comparisons were made between the four codes with good agreement found.
A note on sound radiation from distributed sources

The power output from a normally vibrating strip radiator is expressed in alternative general forms, one of these being chosen to refine and correct some particular estimates given by Heckl for different numerical ratios of strip width to wave length. An exact and explicit calculation is effected for sinusoidal velocity profiles when the strip width equals an integer number of half wave lengths.
Electron delocalization and multifractal scaling in electrified random chains

Abstract The electron localization property of a random chain changing under the influence of a constant electric field has been studied. We have adopted the multifractal scaling formalism to explore the possible localization behavior in the system. We observe that the possible localization behavior with the increase of the electric field is not systematic and shows strong instabilities associated with the local probability variation over the length of the chain. The multifractal scaling study captures the localization aspects along with the strong instability when the electric field is changed by infinitesimal steps for a reasonably large system size.
Details of the structure determination of the sulfated steroids PSDS and PADS : New components of the sea lamprey (Petromyzon marinus) migratory pheromone

The discovery of two new components of the migratory pheromone used by sea lamprey to guide adults to spawning grounds was recently reported. These hold promise for use in a pheromone-based control program for this species, an invasive pest in the Great Lakes. Details of the structure determination of these steroidal bis-sulfates [petromyzosterol disulfate (PSDS, 2) and petromyzonamine disulfate (PADS, 3)] are described here. Pattern matching of 1H NMR data was particularly valuable. This involved comparison of spectra of the natural samples of 2 and 3 with those of appropriate steroidal analogues [e.g., petromyzonol sulfate (PS, 1, a previously known sea lamprey bile acid derivative that is a third component of the migratory pheromone), cholesterol sulfate (6), and squalamine (8)] and model compounds containing the unprecedented aminolactam substructure present in 3. The logic underlying the iterative analyses used is presented.
On string field theory and effective actions

Abstract A truncation of string field theory is compared with the duality invariant effective action of D = 4, N = 4 heterotic strings to cubic order. The three-string vertex must satisfy a set of compatibility conditions. Any cyclic three-string vertex is compatible with the D = 4, N = 4 effective field theory. The effective actions may be useful in understanding the non-polynomial structure and the underlying symmetry of covariant closed string field theory, and in addressing issues of background independence. We also discuss the effective action and string field theory of the N = 2 string.
Black Class Exceptionalism Insights from Direct Democracy on the Race Versus Class Debate

What implications does the growing economic divide be tween poor and middle class blacks have for the political arena? Tradi tional accounts suggest that increased economic diversity should lead to increased political division as the middle class becomes more conser vative. Others maintain that race will continue to trump class because of ongoing racial inequality and widespread racial discrimination. I ar gue for a third alternative. I suggest that for blacks and possibly for other racial minorities increasing class status reinforces race. Class gains may increase the salience of race because economic success often means working in a predominantly white world and experiencing discrimination more regularly. I test these theories using the vote in direct democracy. I find that middle class blacks are more rather than less likely to support a liberal or black agenda. Class works differently for African Americans than for whites. A substantial economic gulf has emerged within the African American commu nity. While the proportion of blacks in the middle class has more than doubled,
Dark Matter Debris Flows in the Milky Way

Abstract We show that subhalos falling into the Milky Way create a flow of tidally-stripped debris particles near the Galactic center with characteristic speed behavior, but no spatial features. Using the Via Lactea-II N-body simulation, we study the unvirialized component arising from particles that were bound in subhalos around the time of reionization but have since been tidally stripped. These debris particles constitute a few percent of the local density today and have speeds peaked at 340 km/s in the solar neighborhood. This spatially-homogeneous velocity substructure has important implications for surveys of low-metallicity stars, as well as direct detection experiments sensitive to dark matter with large scattering thresholds.
Spectral Methods for Time-dependent Studies of Accretion Flows. I. Two-dimensional, Viscous, Hydrodynamic Disks

We present a numerical method for studying the normal modes of accretion flows around black holes. In this first paper, we focus on two-dimensional, viscous, hydrodynamic disks, for which the linear modes have been calculated analytically in previous investigations. We use pseudospectral methods and low-storage Runge-Kutta methods to solve the continuity equation, the Navier-Stokes equation, and the energy equation. We devise a number of test problems to verify the implementation. These tests demonstrate the ability of spectral methods to handle accurately advection problems and to reproduce correctly the stability criteria for differentially rotating hydrodynamic flows. They also show that our implementation is able to handle sound waves correctly with nonreflective boundary conditions, to recover the standard solution for a viscous-spreading ring, and to produce correctly the Shakura-Sunyaev steady-disk solution. Finally, we have applied our algorithm to the problem of a nonaxisymmetric viscous-spreading ring and verify that such configuration is unstable to nonaxisymmetric perturbations.
Phase diagram and electrical behavior of silicon-rich iridium silicide compounds

The iridium-silicon phase diagram on the silicon-rich side was investigated by means of X-ray powder diffraction, density, differential thermal analysis (DTA), metallography, microprobe analysis, and electrical resistivity. Attempts were made to prepare eight previously reported silicon-rich iridium silicide compounds by arc melting and Bridgman-like growth. However, microprobe analysis identified only five distinct compositions: IrSi, Ir4Si5, Ir3Si4, Ir3Si5 and IrSi≈3. The existence of Ir2Si3, Ir4Si7, and IrSi2 could not be confirmed in this study. DTA in conjunction with X-ray powder diffraction confirm polymorphism in IrSi≈3, determined to have orthorhombic and monoclinic unit cells in the high and low temperature forms. A eutectic composition alloy of 80.5 ± 1 at.% Si was observed between IrSi≈3 and silicon. Both Ir4Si5 and Ir3Si4 exhibit distinct metallic behavior while Ir3Si5 is semiconducting. IrSi and IrSi≈3 exhibit nearly temperature-independent electrical resistivities on the order of (5–10) × 10−6ω m.
A Broadly Applicable Method for the Efficient Synthesis of α-O-Linked Glycopeptides and Clustered Sialic Acid Residues

The total syntheses of complex sialylated cell-surface antigens have been accomplished. The target systems include 2,3-STF, STn, 2,6-STF, and glycophorin antigens. In addition, an α-O-linked serine glycoside of an entire Lewis blood group (Y) antigen has been assembled.
Linear electrostatic instability of the electron beam ion source

Abstract Linear plasma fluid theory is used to study the stability of a cold electron beam in Brillouin equilibrium which passes through a stationary cold ion background, with particular interest in stability for parameters relevant to EBIS devices. Dispersion is studied both analytically and numerically. For l = 0, the usual infinite medium two stream instability condition is shown to correspond to a requirement that beam perveance exceed a minimum value, P > 33 μperv; hence, this mode is stable for EBIS (P ≈ 1 μperv). The Brillouin equilibrium rotation is shown to cause an electron-ion rotating stream instability, which is convectively unstable. The l = 1 mode is also found to be unstable. Higher modes numbers, l > 1, are unstable, but have reduced growth. Instability is only weakly affected by finite beam radius and boundary conditions.
Generalized differential Galois theory

A Galois theory of differential fields with parameters is developed in a manner that generalizes Kolchin's theory. It is shown that all connected differential algebraic groups are Galois groups of some appropriate differential field extension.
Validation of Aerosport KB1-C portable metabolic system.

The purpose of this study was to test the validity of the Aerosport KB1-C portable metabolic measurement system against the criterion Douglas bag method. During cycle ergometry, simultaneous measurements of minute ventilation (V E ), oxygen consumption (VO 2 ), and carbon dioxide production (VCO 2 ) were made at rest and at power outputs of 50,100,150, 200, and 250 W. No significant differences (P > 0.05) were observed for V E , VO 2 , and VCO 2 between the KB1-C and Douglas bag at 100, 150, and 250 W, while the KB1-C was significantly different (P < 0.05) from Douglas bag values at rest, 50, and 200 W. R values were found to be significantly different (P < 0.05) at 100, 150, and 200 W, while no significant differences were observed at rest, 50, and 250 W. The fractional concentrations of oxygen (F E O 2 ) and carbon dioxide (F E CO 2 ) were not significantly different at 50, 100, 200, and 250 W while values at rest and 150 W were significantly different (P < 0.05). These findings show that the Aerosport KB1-C portable rmetabolic system is acceptable for measuring oxygen uptake in the range of 1.5 and 3.5 L·min -1 using the medium flow pneumotach setting. At lower intensities, the low-flow pneumotach setting provides acceptable results.
HARD X-RAY AND ULTRAVIOLET EMISSION DURING THE 2011 JUNE 7 SOLAR FLARE

The relationship between X-ray and UV emission during flares, particularly in the context of quasi-periodic pulsations, remains unclear. To address this, we study the impulsive X-ray and UV emission during an eruptive flare on 2011 June 7 utilizing X-ray imaging from RHESSI and UV 1700 A imaging from SDO/AIA. This event is associated with quasi-periodic pulsations in X-ray and possibly UV emission, as well as substantial parallel and perpendicular motion in the hard X-ray footpoints. The motion of the footpoints parallel to the flare ribbons is unusual; it reverses direction on at least two occasions. However, there is no associated short timescale motion of the UV bright regions. Over the same time interval, the footpoints also gradually move apart at v 12 km s–1, consistent with the gradual outward expansion of the UV ribbons and the standard flare model. Additionally, we find that the locations of the brightest X-ray and UV regions are different, particularly during the early portion of the flare impulsive phase, despite their integrated emission being strongly correlated in time. Correlation analysis of measured flare properties, such as the footpoint separation, flare shear, photospheric magnetic field, and coronal reconnection rate, reveals that—in the impulsive phase—the 25-50 keV hard X-ray flux is only weakly correlated with these properties, in contrast with previous studies. We characterize this event in terms of long-term behavior, where the X-ray non-thermal, thermal, and UV emission sources appear temporally and spatially consistent, and short-term behavior, where the emission sources are inconsistent and quasi-periodic pulsations are a dominant feature requiring explanation. We suggest that the short timescale behavior of hard X-ray footpoints and the nature of the observed quasi-periodic pulsations are determined by fundamental, as yet unobserved properties of the reconnection region and particle acceleration sites. This presents a challenge for current three-dimensional flare reconnection models.
Computing super matrix invariants

We develop computational methods for the invariants of the general linear Lie superalgebras involving complex integrals and inner products of Schur functions.
q — deformed dirac monopole with arbitrary charge

We construct the deformed Dirac monopoles on the quantum sphere by giving a global description for arbitrary integer chargen and alternatively by glueing trivial bundles for evenn, and show that they are quantum principal bundles in the sense of Brzezinski and Majid. We also give connections and calculate the analog of Chern numbers by integrating the curvature overS q 2 .
Open spin chains for giant gravitons and relativity

We study open spin chains for strings stretched between giant graviton states in the $ \mathcal{N}=4 $ SYM field theory in the collective coordinate approach. We study the boundary conditions and the effective Hamiltonian of the corresponding spin chain to two loop order. The ground states of the spin chain have energies that match the relativistic dispersion relation characteristic of massive W boson particles on the worldvolume of the giant graviton configurations, up to second order in the limit where the momentum is much larger than the mass. We find evidence for a non-renormalization theorem for the ground state wave function of this spin chain system. We also conjecture a generalization of this result to all loop orders which makes it compatible with a fully relativistic dispersion relation. We show that the conjecture follows if one assumes that the spin chain admits a central charge extension that is sourced by the giant gravitons, generalizing the giant magnon dispersion relation for closed string excitations. This provides evidence for ten dimensional local physics mixing AdS directions and the five-sphere emerging from an $ \mathcal{N}=4 $ SYM computation in the presence of a non-trivial background (made of D-branes) that break the conformal field theory of the system.
Generalized quantum dynamics

Abstract We propose a generalization of Heisenberg picture quantum mechanics in which a lagrangian and hamiltonian dynamics is formulated directly for dynamical systems on a manifold with noncommuting coordinates, which act as operators on an underlying Hilbert space. This is accomplished by defining the lagrangian and hamiltonian as the real part of a graded total trace over the underlying Hilbert space, permitting a consistent definition of the first variational derivative with respect to a general operator-valued coordinate. The hamiltonian form of the equations is expressed in terms of a generalized bracket operation, which obeys a Jacobi identity. The formalism permits the natural implementation of gauge invariance under operator-valued gauge transformations. When an operator hamiltonian exists as well as a total trace hamiltonian, as is generally the case in complex quantum mechanics, one can make an operator gauge transformation from the Heisenberg to the Schrodinger picture. When applied to complex quantum mechanical systems with one bosonic or fermionic degree of freedom, the formalism gives the usual operator equations of motion, with the canonical commutation relations emerging as constraints associated with the operator gauge invariance. More generally, our methods permit the formulation of quaternionic quantum field theories with operator-valued gauge invariance, in which we conjecture that the operator constraints act as a generalization of the usual canonical commutators.
Shear stress attenuates apoptosis due to TNFα, oxidative stress, and serum depletion via death-associated protein kinase (DAPK) expression

Misdirected apoptosis in endothelial cells participates in the development of pathological conditions such as atherosclerosis. Tight regulation of apoptosis is necessary to ensure normal cell function. The rate of cell turnover is increased at sites prone to lesion development. Laminar shear stress is protective against atherosclerosis, and helps suppress apoptosis induced by cytokines, oxidative stress, and serum depletion. Current Studies have shown that the pro-apoptotic DAPK expression and function to be regulated in part by shear stress, and that shearing cells already treated with cytokine tumor necrosis factor (TNF) α significantly reduced apoptosis. We investigate further the suppression of endothelial apoptosis by shear stress with other apoptotic triggers, and the involvement of DAPK and caspase 3/7. We have shown that exposure to shear stress (12 dynes/cm2 for 6 hrs) suppressed endothelial apoptosis triggered by cytokine (TNFα), oxidative stress (H2O2), and serum depletion, either before or after a long term (18 hr) induction. This is correlated with a parallel decrease of DAPK expression and caspase activity compared to non-sheared cells. We found similar modulation of DAPK and apoptosis by shear stress with other pro-apoptotic signals. Changes in DAPK and caspase 3/7 are directly correlated to changes in apoptosis. Interestingly, shear stress applied to cells prior to induction with apoptosis agents resulted in a higher suppression of apoptosis and DAPK and caspase activity, compared to applying shear stress post induction. This is correlated with a higher expression and activation of DAPK in cells sheared at the end of 24-hr experiment. Also, shear stress alone also induced higher apoptosis and DAPK expression, and the effect is sustained even after 18 hrs incubation in static condition, compared to non-sheared cells. Overall, we show that laminar shear stress inhibits various apoptosis pathways by modulating DAPK activity, as well as caspase activation, in a time-dependent manner. Shear stress could target DAPK as a converging point to exert its effects of suppressing endothelial apoptosis. The temporal shear stress stimulation of DAPK and its role in different apoptosis pathways may help identify key mechanisms of the endothelial mechanotransduction pathway.
Seeing the QCD phase transition with phi mesons

Abstract A double phi peak structure in the dilepton invariant mass spectrum from ultrarelativistic heavy ion collisions is proposed as a signal for the phase transition from the quark-gluon plasma to the hadronic matter. The low mass phi peak results from the decay of phi mesons with reduced in-medium mass durinf the transition. Furthermore, the measurement of the transverse momentum distribution of these low mass phi mesons offers a viable means for determining the temperature of the phase transition.
A modular, air-stable nickel precatalyst.

The synthesis and catalytic activity of [(TMEDA)Ni(o-tolyl)Cl], an air-stable, crystalline solid, is described. This complex is an effective precatalyst in a variety of nickel-catalyzed transformations. The lability of TMEDA allows a wide variety of ligands to be used, including mono- and bidentate phosphines, diimines, and N-heterocyclic carbenes. Preliminary mechanistic studies are also reported, which suggest that [(TMEDA)Ni(o-tolyl)Cl] can activate by either a Ni–B or Ni–Ni transmetalation event, depending on the reaction conditions.
Direct β‑Functionalization of Cyclic Ketones with Aryl Ketones via the Merger of Photoredox and Organocatalysis

The direct β-coupling of cyclic ketones with aryl ketones has been achieved via the synergistic combination of photoredox catalysis and organocatalysis. Diaryl oxymethyl or aryl–alkyl oxymethyl radicals, transiently generated via single-electron reduction of ketone precursors, readily merge with β-enaminyl radical species, generated by photon-induced enamine oxidation, to produce γ-hydroxyketone adducts. Experimental evidence indicates that two discrete reaction pathways can be operable in this process depending upon the nature of the ketyl radical precursor and the photocatalyst.
MEAN VALUE INEQUALITIES AND CONDITIONS TO EXTEND RICCI FLOW

This paper concerns conditions related to the rst nite singularity time of a Ricci ow solution on a closed manifold. In particular, we provide a systematic approach to the mean value inequality method, suggested by N. Le (13) and F. He (11). We also display a close connection between this method and time slice analysis as in (23). As an application, we prove several inequalities for a Ricci ow solution on a manifold with nonnegative isotropic curvature.
The design and synthesis of a novel series of indole derived selective ETA antagonists

Abstract Conformational constraint has been used as the key design element in the identification of a series of potent and selective ET A antagonists. The most potent antagonist, 32 , (ET A IC 50 =0.55 nM) is 722-fold selective over the ET B receptor, as measured by binding experiments.
Centrality of the congruence kernel for elementary subgroups of Chevalley groups of rank >1 over noetherian rings

We prove the centrality of the congruence kernel for the elementary subgroup of a Chevalley group G of rank >1 over an arbitrary noetherian ring R (under some minor restrictions on R if G is of type C_n or G_2).
Dynamic interactive epistemology

Abstract The epistemic program in game theory uses formal models of interactive reasoning to provide foundations for various game-theoretic solution concepts. Much of this work is based around the (static) Aumann structure model of interactive epistemology, but more recently dynamic models of interactive reasoning have been developed, most notably by Stalnaker [Econ. Philos. 12 (1996) 133–163] and Battigalli and Siniscalchi [J. Econ. Theory 88 (1999) 188–230], and used to analyze rational play in extensive form games. But while the properties of Aumann structures are well understood, without a formal language in which belief and belief revision statements can be expressed, it is unclear exactly what are the properties of these dynamic models. Here we investigate this question by defining such a language. A semantics and syntax are presented, with soundness and completeness theorems linking the two.
Performance Evaluation of Medium Access Control Protocols for Distributed Digital Avionics

The paper presents the results of an ongoing research project where the objectives are to evaluate medium access control (MAC) protocols in view of the requirements for distributed digital flight control systems (DDFCS) of advanced aircraft and to recommend a specific protocol for their prototype development. The selection of an appropriate MAC protocol is critical for the dynamic performance of an aircraft because the DDFCS, in addition to the sampling time delay, is subject to time-varying transport delays due to data latency of messages at different terminals of the control loop. The SAE linear token bus, SAE token ring and the conventional MIL-STD-1553B protocols have been analyzed using combined discrete-event and continuous-time simulation techniques. The impact of data latency on the dynamic performance of an advanced aircraft is illustrated by simulation of the closed loop DDFCS.
Spicules and Surges

It is argued that spicules, macrospicules and surges are manifestations of the same phenomenon occurring on different scales. A mechanism that can be successfully applied to explain the phenomenon on all three scales is sought.
Triggered Release from Polymer Capsules

Stimuli-responsive capsules are of interest in drug delivery, fragrance release, food preservation, and self-healing materials. Many methods are used to trigger the release of encapsulated contents. Here we highlight mechanisms for the controlled release of encapsulated cargo that utilize chemical reactions occurring in solid polymeric shell walls. Triggering mechanisms responsible for covalent bond cleavage that result in the release of capsule contents include chemical, biological, light, thermal, magnetic, and electrical stimuli. We present methods for encapsulation and release, triggering methods, and mechanisms and conclude with our opinions on interesting obstacles for chemically induced activation with relevance for controlled release.
New magnetic structures for switching converters

In the past the majority of power processing applications have been centered around a very few standard switching converter topologies. Recently, a number of new converter topologies have been proposed in order to find the best possible electrical inter connection of power processing elements: switches, storage components, and transformers, that would yield the highest efficiency and best performance. However the equally important and complementary problem of their best magnetic interconnection has been completely overlooked. In some new converter structures, the nature of the switching process and existing waveforms allows integration of previously separate inductors and transformers into a single magnetic structure. Several such magnetic core structures are proposed and analyzed, which lead to further converter simplifications and performance improvements.
Tree Induction of Spatial Choice Behavior

Discussed is the merit of inductive learning as a tool with which to discover geographic knowledge in data-rich environments, and particularly as an analysis tool in spatial decision-making theory. The capability and applicability of Quinlan's C4.5 decision tree induction algorithm to the class of problems involving the choice among discrete travel destinations within an urban area are analyzed. The C4.5 algorithm and its relation to other decision tree induction algorithms and to spatial behavioral modeling are described, and its implementation on spatial behavior data from the Minneapolis-St. Paul metropolitan area is illustrated.
Non-abelian convexity by symplectic cuts

Abstract We give new proofs of the convexity and connectedness properties of the moment map using the technique of symplectic cutting and extend these results to the case of orbifolds.
VIABILITY AND DISTRIBUTION OF BACTERIA AFTER PASSAGE THROUGH A CIRCLE ANAESTHETIC SYSTEM

We have assessed in vitro the viability of eight species of micro-organism suspended as aerosols and passed through a soda-lime absorber rebreathing system. As had been predicted, the soda-lime exerted a potent cidal effect on non-sporing organisms, all of which were rendered non-viable. One percent of the spore bearing organism. Bacillus subtilis, was still viable after 30 min contact. Although Bacillus subtilis is an organism of low pathogenicity, spores may be more resistant to the alkaline medium of the soda-lime. The micro-organisms were observed to lodge in all components of the breathing system, with the greatest concentration being recovered from the corrugated tubing. We recommend that disposable components of the circle breathing system should be changed, and the non-disposable parts sterilized or disinfected, daily. Soda-lime cannisters should be sterilized or disinfected when changing the soda-lime.
Aggregation of non-bonding molecules in a rapidly growing gel

The aggregation of non-bonding molecules in a rapidly growing gel is studied under three different conditions by means of Molecular Dynamics simulations. The aggregation takes place even under the unfavorable condition when the non-bonding molecules constitute only a small fraction of the total. The results also show that the morphology of the growing domains is different depending on the concentration of the non-bonding molecules.
Fully reagent-controlled asymmetric synthesis of (-)-spongidepsin via the Zr-catalyzed asymmetric carboalumination of alkenes (ZACA reaction).

The ZACA reaction has been shown to proceed satisfactorily with internally OH-substituted 1-alkenes, provided that the OH group is unprotected and non-allylic. This reaction was used for reagent-controlled asymmetric construction of 3. Allylic alcohol was converted to 2 in seven steps via iterative ZACA processes and simple chromatography. (−)-Spongidepsin (1) was synthesized by using 2 and 3 through application of the esterification−amidation−ring-closing metathesis protocol previously reported.
A non-singular infra-red flow from D=5 gauged supergravity

Abstract We discuss domain wall solutions of 5-dimensional supergravity corresponding to a cosine-superpotential, which is derived by a gauging of the two Abelian isometries of the scalar coset SU(2,1)/U(2). We argue that this potential can be obtained from M-theory compactification in the presence of G-fluxes and an M5-brane instanton gas. If we decouple the volume scalar of the internal space, the superpotential allows for two extrema, which are either ultra-violet or infra-red attractive. Asymptotically we approach therefore either the boundary or the Killing horizon of an anti-deSitter space or flat spacetime for a vanishing cosmological constant. If the volume scalar does not decouple, we obtain a run-away potential corresponding to dilatonic domain walls, which always run towards a vanishing cosmological constant.
Robust microprocessor control of robot manipulators

Abstract In this paper the problem of robust tracking for robot manipulators in the presence of uncertainty and input constraints is studied. Using the theory of uncertain dynamical systems, robust non-linear control strategies, with guaranteed tracking properties that can be quantified given bounds on the extent of model uncertainty, sensor noise, input disturbances, etc., are derived. A torque optimization strategy is also utilized to optimize the joint torques in the event of actuator saturation. The algorithm has been implemented using a single Motorola 12 MHz MC68000 microprocessor on a three-link revolute joint manipulator constructed by the School of Mechanical Engineering at Cornell University. Experimental results are presented here showing the feasibility and performance of the control stragegy.
Finding Dantzig selectors with a proximity operator based fixed-point algorithm

A simple iterative method for finding the Dantzig selector, designed for linear regression problems, is introduced. The method consists of two stages. The first stage approximates the Dantzig selector through a fixed-point formulation of solutions to the Dantzig selector problem; the second stage constructs a new estimator by regressing data onto the support of the approximated Dantzig selector. The proposed method is compared to an alternating direction method. The results of numerical simulations using both the proposed method and the alternating direction method on synthetic and real-world data sets are presented. The numerical simulations demonstrate that the two methods produce results of similar quality; however the proposed method tends to be significantly faster.
Is routine cesarean section necessary for vertex-breech and vertex-transverse twin gestations?

Ninety-three vertex-breech and 42 vertex-transverse twin gestations were managed at Yale-New Haven Medical Center during a 5-year period. Antepartum diagnosis of twin gestation occurred in 93% of the cases, and diagnosis was made before delivery of the second twin in 97% of the cases. Seventy-two (78%) of the vertex-breech and 22 (53%) of the vertex-transverse twins were delivered vaginally. Breech extraction was used for delivery of 76 second twins. Below a birth weight of 1,500 gm, there were six neonatal deaths, four cases of documented intraventricular hemorrhage, and a 67% occurrence of depressed 5-minute Apgar scores. Above a birth weight of 1,500 gm, there were no cases of neonatal death or documented intraventricular hemorrhage and a 5% occurrence of moderately depressed 5-minute Apgar scores. Birth trauma occurred in a 3,420 gm second twin delivered by breech extraction. This infant suffered a greenstick fracture of the right clavicle and a nondisplaced fracture of the right humerus that was not associated with permanent residual injury. We think that, for birth weights >1,500 gm, routine cesarean section for vertex-breech or vertex-transverse twin gestation may not be necessary.
Leveraging Linear and Mixed Integer Programming for SMT

SMT solvers combine SAT reasoning with specialized theory solvers either to find a feasible solution to a set of constraints or to prove that no such solution exists. Linear programming (LP) solvers come from the tradition of optimization, and are designed to find feasible solutions that are optimal with respect to some optimization function. Typical LP solvers are designed to solve large systems quickly using floating point arithmetic. Because floating point arithmetic is inexact, rounding errors can lead to incorrect results, making inexact solvers inappropriate for direct use in theorem proving. Previous efforts to leverage such solvers in the context of SMT have concluded that in addition to being potentially unsound, such solvers are too heavyweight to compete in the context of SMT. In this paper, we describe a technique for integrating LP solvers that improves the performance of SMT solvers without compromising correctness. These techniques have been implemented using the SMT solver CVC4 and the LP solver GLPK. Experiments show that this implementation outperforms other state-of-the-art SMT solvers on the QF_LRA SMT-LIB benchmarks and is competitive on the QF_LIA benchmarks.
The Goals of U.S. Agricultural Policy: A Mechanism Design Approach

This article examines motivations underlying the government's choice of alternative policy mechanisms for subsidizing agriculture. Optimal policies are analyzed for three government objectives: one where the government wishes to ensure a minimum level of net income for all farmers, a second where the government's only concern is to transfer income from consumers and taxpayers to the farm sector, and a final “augmented” income-transfer objective. The analysis offers an explanation for agricultural policy mechanisms that involve overproduction by high-cost producers, relative to a free-market equilibrium. Such a distortion might arise from the existence of nonmarket values for the production of relatively high-cost farmers in the government's objective.
Convergence Characteristics of Nonlinear Phase Retrieval

We investigate the convergence characteristics of a phase retrieval algorithm using nonlinear diversity. The nonlinear algorithm has a non-monotonic convergence profile, giving a criterion for minimum phase error in the reconstruction.
Constitutive model with strain softening

Abstract The aim of this paper is to propose a simple yet realistic model for the mechanical behavior of geologic materials such as concrete and rock. The effect of structural changes in such materials is addressed and incorporated in the theory through a tensor form of a damage variable. It is shown that formation of damage is responsible for the softening in strength observed in experiments, for the degradation of the elastic shear modulus, and for induced anisotropy. A generalized plasticity model is incorporated for the so-called topical or continuum part of the behavior, whereas the damage part is represented by the so-called stress-relieved behavior. The parameters required to define the model are identified and determined from multiaxial testing of a concrete. The predictions are compared with observed behavior for a number of stress paths. The model shows very good agreement with the observed response.
Derivation of fluorine‐containing pyridine dicarboxylates. II. Elaboration at the 4‐position

In response to the bio-activity found in fluorine-containing 4-alkyl-3, 5-pyridinedicarboxylates, a series of novel 4-substituted derivatives, not directly available by Hantzsch sequences, were prepared. Starting 4-alkylpyridines, 1, were converted via enamine 2 to materials 3–8. Derivatives 9–16 in turn were derived from aldehyde 3, while acid derivatives 28–36 were prepared from 14. Addition of oxygen, sulfur, and carbenoids effected conversion of 4-allylpyridine 16 to epoxy and cyclopropyl derivative 16–22. A number of neighboring group effects were noted, including those forming the fused-ring systems 23-27.
Aerodynamic Heating on 3-D Bodies Including the Effects of Entropy-Layer Swallowing

A relatively simple method is presented to include the effects of entropy-layer swallowing in a method developed previously for calculating laminar, transitional, and turbulent heating rates on three-dimensional bodies in hypersonic flows. The boundary layer swallows the entropy layer when the boundary layer downstream of the nose region has entrained those streamlines which passed through the nearly normal part of the bow shock wave. The entropy at the edge of the boundary layer is then determined by equating the mass flow inside the boundary layer to that entering part of the bow shock wave. A new inviscid flowfield solution, which is an extension of Maslen's axisymmetric method, is developed to calculate the three-dimensional shock shape and couple the inviscid solution with the viscous solution. The calculated heating rates compare favorably with Mayne's theory and experimental data for blunted circular and elliptical cones at angles of attack. The effects of entropy layer swallowing on the calculated heating rates were small for laminar heating but large increases were noted for the turbulent heating rates. The computer program developed to calculate the results presented herein required only about 7 sec per streamline on the IM 370/165 computer.