cssi/SciSciGPT-SciSciNet huggingface dataset:
Catheter ablation of supraventricular arrhythmias: state of the art.

The era of catheter ablation for the treatment of arrhythmias began in 1981, when Dr. Melvin Scheinman performed the first atrioventricular junction ablation using direct-current shocks in a patient with drug-refractory atrial fibrillation and an uncontrolled ventricular rate.1 Because of the barotrauma associated with intracardiac high-energy shocks, direct-current catheter ablation played only a limited role in the treatment of arrhythmias. With the advent of radiofrequency catheter ablation in the late 1980s, the range of arrhythmias amenable to catheter ablation and the number of patients who could be treated safely by catheter ablation vastly expanded. In the past decade, radiofrequency catheter ablation has become firmly established as first-line therapy for paroxysmal supraventricular tachycardia and typical atrial flutter. Furthermore, although still in an evolutionary phase, catheter ablation to eliminate atrial fibrillation has been demonstrated in the past 5 years to be feasible and clinically useful. The intent of this article is to review the current status of catheter ablation for the treatment of paroxysmal supraventricular tachycardia, atrial flutter, and atrial fibrillation.
Enantioselective Friedel-Crafts reaction of indoles with carbonyl compounds catalyzed by bifunctional cinchona alkaloids.

In this communication, we report an efficient asymmetric Friedel−Crafts reaction that, unprecedently, is applicable to a wide range of both indoles and carbonyls. The use of a readily accessible catalyst in combination with a high enantioselectivity that is insensitive to reaction concentration, temperature, air, and moisture should allow this reaction to provide useful enantioselective access to new chiral indole derivatives.
Titania-silica as catalysts : molecular structural characteristics and physico-chemical properties

Abstract Recent results on characterization and applications of titania–silica materials as photocatalysts, acid catalysts and oxidation catalysts are reviewed. The similarities and differences in structural characteristics and physico-chemical properties between titania–silica mixed and supported oxides are emphasized. The generation of new catalytic active sites either on the silica surface or in the silica matrix is discussed with respect to the formation of Ti–O–Si bonds and the local structure. The insights obtained from these studies allow a fundamental understanding of the relationships between the structural characteristics and the physico-chemical/reactivity properties of titania–silica catalysts.
A new cutaneous sign of mercury poisoning

Chronic mercury poisoning is becoming a health concern because of extensive pollution of water and fish, and the increasing consumption of fish in the human diet. Mercury is extremely toxic to the body, especially the central nervous system, but diagnosis is difficult because of the lack of specific signs. A total of 11 patients were observed to have a nonpruritic or mildly pruritic discreet papular and papulovesicular eruption that correlated with high blood mercury levels. The mercury evidently came from increased seafood consumption. All of the patients improved when they were placed on either a seafood-free diet or chelation therapy. Physicians should suspect mercury poisoning in patients who eat a high-seafood diet who present with an asymptomatic or mildly pruritic papular or papulovesicular eruption.
Inference on the Quantile Regression Process

Tests based on the quantile regression process can be formulated like the classical Kolmogorov–Smirnov and Cramer–von–Mises tests of goodness–of–fit employing the theory of Bessel processes as in Kiefer (1959). However, it is frequently desirable to formulate hypotheses involving unknown nuisance parameters, thereby jeopardizing the distribution free character of these tests. We characterize this situation as “the Durbin problem” since it was posed in Durbin (1973), for parametric empirical processes. In this paper we consider an approach to the Durbin problem involving a martingale transformation of the parametric empirical process suggested by Khmaladze (1981) and show that it can be adapted to a wide variety of inference problems involving the quantile regression process. In particular, we suggest new tests of the location shift and location–scale shift models that underlie much of classical econometric inference. The methods are illustrated with a reanalysis of data on unemployment durations from the Pennsylvania Reemployment Bonus Experiments. The Pennsylvania experiments, conducted in 1988–89, were designed to test the efficacy of cash bonuses paid for early reemployment in shortening the duration of insured unemployment spells.
Chlorpromazine: a potential physiological teratogen.

Chlorpromazine, a drug commonly administered as an antiemetic during pregnancy, when administered prenatally to chick embryos, was associated postnatally with a ‘curled toe’ anomaly (ED 50% of 88 μg/egg for the 4-day-embryo).
BROAD SPECTRUM ANTI-PLATELET AGGREGATION THERAPY IMPROVES POSTISCHEMIC CEREBRAL BLOOD FLOW (CBF) AND CORTICAL SOMATOSENSORY EVOKED RESPONSE (CSER) RECOVERY, BUT FAILS TO BLOCK PLATELET ACCUMULATION IN THE DAMAGED HEMISPHERE

Previously we showed that platelets accumulate in areas of low CBF 4h after brain ischemia. Similarly, CSER and CBF recovery after brain ischemia was enhanced in dogs treated with either prostacyclin (PGI2) + indomethacin or the platelet-activating factor (PAF) receptor antagonist kadsurenone. Since these treatments inhibit platelet aggregation, we hypothesized that their beneficial effects were mediated via inhibition of platelet accumulation. To test this hypothesis, 22 dogs with 111In-labeled platelets were subjected to 1h of ischemia of the right hemisphere by air embolism. CSER in the right hemisphere was monitored during reperfusion, while CBF (autoradiography) and platelet accumulation (R-L ratio of 111In activity) were measured after 4h of reperfusion. 12 dogs served as controls, 6 were treated with PGI2 + indomethacin and 4 with kadsurenone. Both treatments enhanced CSER recovery after Ih of reperfusion and eliminated neuron-disabling CBF at 4h (defined as <15ml/ 100g/min in gray matter and <6ml/100g in white). Despite this, platelet accumulation was not blocked by either treatment. Anti-pfatelet aggregation therapy does not block postischemic platelet accumulation in the brain. Other effects of these treatments including improved CBF may contribute to enhanced recovery.
Luminous Supersoft X-Ray Sources in External Galaxies

We use a set of conservative criteria to identify luminous supersoft X-ray sources (SSSs) in external galaxies. We test this approach on blackbody models and then apply it to Chandra data from four galaxies: an elliptical galaxy (NGC 4967), two face-on spiral galaxies (M101 and M83), and an interacting galaxy (M51). We find SSSs in every galaxy and estimate that the total SSS population of sources with L > 1037 ergs s-1 in each galaxy is at least several hundred and could be significantly larger. In addition, we discover two intriguing features of galactic populations of SSSs. First, there are significant subpopulations of high-luminosity sources; the bolometric luminosities can exceed 1039 ergs s-1. Second, in the spiral galaxies M101, M83, and M51, SSSs appear to be associated with the spiral arms. This may indicate that some SSSs are young systems, possibly younger than 108 yr.
Unramified division algebras do not always contain Azumaya maximal orders

We show that, in general, over a regular integral noetherian affine scheme X of dimension at least 6, there exist Brauer classes on X for which the associated division algebras over the generic point have no Azumaya maximal orders over X. Despite the algebraic nature of the result, our proof relies on the topology of classifying spaces of algebraic groups.
Displacement of X-ray sources from star clusters in starburst galaxies

We examine the spatial offsets between X-ray point sources and star clusters in three starburst galaxies. We find that the X-ray sources are preferentially located near the star clusters. Because the star clusters are very good tracers of the star formation activity in the galaxies, this indicates that the X-ray sources are young objects associated with current star formation. We find significant displacements of the X-ray sources from the clusters. These displacements are likely due to motion of the X-ray sources and indicates that they are X-ray binaries. We find that brighter X-ray sources preferentially occur closer to clusters. The absence of very bright sources at large displacements from clusters may help constrain models of the sources.
Universal Source Coding for Monotonic and Fast Decaying Monotonic Distributions

We study universal compression of sequences generated by monotonic distributions. We show that for a monotonic distribution over an alphabet of size k, each probability parameter costs essentially 0.5log(n/k3) bits, where n is the coded sequence length, as long as k=o(n1/3). Otherwise, for k=O(n), the total average sequence redundancy is O(n1/3+e) bits overall. We then show that there exists a sub-class of monotonic distributions over infinite alphabets for which redundancy of O(n1/3+e) bits overall is still achievable. This class contains fast decaying distributions, including many distributions over the integers such as the family of Zipf distributions and geometric distributions. For some slower decays, including other distributions over the integers, redundancy of o(n) bits overall is achievable. A method to compute specific redundancy rates for such distributions is derived. The results are specifically true for finite entropy monotonic distributions. Finally, we study individual sequence redundancy behavior assuming a sequence is governed by a monotonic distribution. We show that for sequences whose empirical distributions are monotonic, individual redundancy bounds even tighter than those in the average case can be obtained. The relation of universal compression with monotonic distributions to universal compression of patterns of sequences is demonstrated.
Anomalous diffusion of a tracer advected by wave turbulence

We consider the advection of a passive tracer when the velocity field is a superposition of random waves. Green's function for the turbulent transport (turbulent diffusion and turbulent drift) is derived. This Green's function is shown to imply sub-diffusive or super-diffusive behavior of the tracer. For the analysis we introduce the statistical near-identity transformation. The results are confirmed by numerical simulations.
Tandem photochemical or thermal [1,5]-H, thermal [1,5]-Si migrations of vinyl silanes

The irradiation or thermolysis of o-hydroxystryryl vinylsilanes results in migration of the silyl group to the phenolic oxygen via consecutive [1,5]-H and [1,5]-Si shifts.
Sustainability assessment at the transportation planning level: Performance measures and indexes

While the definition of a sustainable transportation system is varied, there is emerging consensus that transportation system sustainability should capture attributes of system effectiveness and system impacts on economic development, environmental integrity, and social quality of life. Sustainability assessment can be incorporated at the planning level in order to influence decision making, and support policies that affect regional sustainability. This paper reviews methodologies that can be applied in sustainability assessment in transportation planning in order to shed light on the procedures being used to incorporate sustainability more effectively in the planning process. Using data from the Atlanta Metropolitan Region, the study identifies performance measures based on sustainability issues and regional goals and evaluates proposed transportation and land use alternatives. The study evaluates and discusses several performance measures and aggregates them into indexes representing four parameters of sustainability: system effectiveness, environmental, economic, and social impacts, to enable visualization and assessment of tradeoffs and dominance for the competing alternatives. This study is potentially useful to agencies interested in understanding the range of tools being used for sustainability assessment, expanding or refining their performance measures to capture sustainability in transportation planning, and using them in evaluating tradeoffs among competing alternatives as well as in identifying dominant alternatives.
Ferromagnetic Ordering of Energy Levels

We study a natural conjecture regarding ferromagnetic ordering of energy levels in the Heisenberg model which complements the Lieb–Mattis Theorem of 1962 for antiferromagnets: for ferromagnetic Heisenberg models the lowest energies in each subspace of fixed total spin are strictly ordered according to the total spin, with the lowest, i.e., the ground state, belonging to the maximal total spin subspace. Our main result is a proof of this conjecture for the spin-1/2 Heisenberg XXX and XXZ ferromagnets in one dimension. Our proof has two main ingredients. The first is an extension of a result of Koma and Nachtergaele which shows that monotonicity as a function of the total spin follows from the monotonicity of the ground state energy in each total spin subspace as a function of the length of the chain. For the second part of the proof we use the Temperley–Lieb algebra to calculate, in a suitable basis, the matrix elements of the Hamiltonian restricted to each subspace of the highest weight vectors with a given total spin. We then show that the positivity properties of these matrix elements imply the necessary monotonicity in the volume. Our method also shows that the first excited state of the XXX ferromagnet on any finite tree has one less than maximal total spin.
Dynamics of Tubes in Fluid With Tube-Baffle Interaction

Three series of tests are performed to evaluate the effects of tube to tube-support-plate (TSP) clearance on tube dynamic characteristics and instability phenomena for tube arrays in crossflow. Test results show that, for relatively large clearances, tubes may possess TSP-inactive modes in which the tubes rattle inside some of the tube-support-plate holes, and that the natural frequencies of TSP-inactive modes are lower than those of TSP-active modes, in which the support plates provide knife-edge type support. Tube response characteristics associated with TSP-inactive modes are sensitive to tube-to-TSP clearance, TSP thickness, excitation amplitude, tube alignment, and the fluid inside the clearance. In addition, tube response is intrinsically nonlinear, with the dominance of TSP-inactive or TSP-active modes depending on the magnitudes of different system parameters. In general, such a system is difficult to model; only a full-scale test can provide all the necessary characteristics. A tube array supported by TSPs with relatively large clearances may be subjected to dynamic instability in some of the TSP-inactive modes; tube response characteristics and impact forces on TSPs for a tube row are studied in detail in this report. Tube displacements associated with the instability of a TSP-inactive mode are small; however, impacts of the tube against TSPs may result in significant damage in a relatively short time.
Institutional Analysis Criteria for Water Supply Planning

: This paper discusses the selection and use of criteria for an institutional analysis of municipal water supply conducted in anchorage, Alaska. Although not universally acepted or used. evaluation criteria for most technical fields have been established either formally or informally. Cost-benefit rtios, cost-effectiveness, and environmental impacts are examples of technical evaluation criteria that can be quantified relatively easily (although poorly in some cases). The field of institutional analysis has evaluative criteria that are much less readily defined than those of technical fields, in part because many of the criteria are not quantifiable and in part because the area of the study is new.
A new stochastic path-length tree methodology for constructing communication networks

Network analysis has become a popular method for identifying the communication structure in a system where positional and relational aspects are important. In this paper, a maximum likelihood based methodology is presented that allows for the analysis of binary sociometric data. This methodology provides a network representation via estimated path-length or additive trees that indicate the distance between all pairs of members. The methodology is distinguished from traditional hierarchical clustering based procedures by its direct consideration of the asymmetry in a typical communication process, the simultaneous representation of structural characteristics (e.g., clique membership, clique cohesiveness), and the identification of the specialized communication roles of each member (e.g., opinion leader, liaison). A penalty function algorithm is developed and its performance is investigated via a Monte Carlo analysis with synthetic data. An application examining information flows among managers is presented. Finally, directions for future research are suggested.
Longitudinal changes in cardiorespiratory fitness: measurement error or true change?

PURPOSE This study examined the thesis that the reported Aerobics Center Longitudinal Study (ACLS) mortality reductions associated with improved cardiorespiratory fitness were because of measurement error of serial treadmill tests. We tested the research hypothesis that longitudinal changes in cardiorespiratory fitness of the ACLS cohort were a multivariate function of changes in self-report physical activity (SR-PA), resting heart rate, and body mass index (BMI). METHODS We used the results of three serial maximal treadmill tests (T1, T2, and T3) to evaluate the serial changes in cardiorespiratory fitness of 4675 men. The mean duration between the three serial tests examined was: T2 - T1, 1.9 yr; T3 - T2, 6.1 yr; and T3 - T1, 8.0 yr. Maximum and resting heart rate, BMI, SR-PA, and maximum Balke treadmill duration were measured on each occasion. RESULTS General linear models analysis showed that with change in maximum heart rate statistically controlled change in treadmill time performance was a function of independent changes in SR-PA, BMI, and R-HR. These variables accounted for significant (P < 0.001) proportions (7%, 9%, and 12%) of the change in treadmill time variance. Those men who increased their SR-PA and lowered their BMI and resting heart rate gained the most fitness between serial tests. CONCLUSIONS These results support the research hypothesis tested. Variations in serial ACLS treadmill tests are not just due to measurement error alone, but also to systematic variation linked with changes in lifestyle.
Computer programming fundamentals for non-computer scientists

Computing for Social Scientists is one of a series of introductory computer programming courses designed for specialists, this one for graduate level social science students. A wide spectrum of disciplines was represented including anthropology, sociology, psychology, history, economics, linguistics, and urban planning. The students also had a highly varied background in mathematics---from one college math course through advanced calculus; from strong statistics to no statistical background whatsoever.
Multistep synthesis of the SrFeO2F perovskite oxyfluoride via the SrFeO2 infinite-layer intermediate

Abstract The SrFeO 2 F oxyﬂuoride was prepared through a low temperature, multistep synthetic route starting with the SrFeO 3− x perovskite via the SrFeO 2 inﬁnite layer intermediate phase. In the final step SrFeO 2 F was formed by reacting SrFeO 2 with XeF 2 at 150 °C. In spite of utilizing an intermediate with layered ordering of oxygen vacancies, disordered SrFeO 2 F was synthesized. Rietveld reﬁnement of synchrotron powder diffraction data did not reveal any signs of tetragonal distortion predicted by DFT calculations for SrFeO 2 F with layered O/F ordering. Significantly, the magnetic properties observed are drastically different from those reported earlier in the literature indicating that the properties of O/F disordered phases depend on the degree of short range ordering. Mossbauer spectroscopy measurements revealed the predominance of cis fluorine configuration in FeO 4 F 2 polyhedra, confirming a difference in local Fe coordination in comparison with O/F disordered SrFeO 2 F.
The Impact of the Active Management of Risk in Pregnancy at Term on Birth Outcomes: a randomized clinical trial

Objective The purpose of this study was to compare birth outcomes that result from the active management of risk in pregnancy at term (AMOR-IPAT) to those outcomes that result from standard management. Study Design This was a randomized clinical trial with 270 women of mixed parity. AMOR-IPAT used preventive labor induction to ensure delivery before the end of an estimated optimal time of delivery. Rates of 4 adverse obstetric events and 2 composite measures were used to evaluate birth outcomes. Results The AMOR-IPAT–exposed group had a similar cesarean delivery rate (10.3% vs 14.9%; P = .25), but a lower neonatal intensive care unit admission rate (1.5% vs 6.7%; P = .03), a higher uncomplicated vaginal birth rate (73.5% vs 62.8%; P = .046), and a lower mean Adverse Outcome Index score (1.4 vs 8.6; P = .03). Conclusion AMOR-IPAT exposure improved the pattern of birth outcomes. Larger randomized clinical trials are needed to explore further the impact of AMOR-IPAT on birth outcomes and to determine the best methods of preventive labor induction.
Granular discharge rate for submerged hoppers

The discharge of spherical grains from a hole in the bottom of a right circular cylinder is measured with the entire system underwater. We find that the discharge rate depends on filling height, in contrast to the well-known case of dry non-cohesive grains. It is further surprising that the rate increases up to about twenty five percent, as the hopper empties and the granular pressure head decreases. For deep filling, where the discharge rate is constant, we measure the behavior as a function of both grain and hole diameters. The discharge rate scale is set by the product of hole area and the terminal falling speed of isolated grains. But there is a small-hole cutoff of about two and half grain diameters, which is larger than the analogous cutoff in the Beverloo equation for dry grains. Received: 11 September 2014, Accepted: 10 October 2014; Reviewed by: L. Staron, CNRS, Universite Pierre et Marie Curie, Institut Le Rond d'Alembert, Paris, France; Edited by: L. A. Pugnaloni; DOI: http://dx.doi.org/10.4279/PIP.060009 Cite as: T J Wilson, C R Pfeifer, N Meysingier, D J Durian, Papers in Physics 6, 060009 (2014)
Contractibility of fixed point sets of auter space

Abstract We show that for every finite subgroup G of Aut(Fn), the fixed point subcomplex XnG is contractible, where Fn is the free group on n letters and Xn is the spine of “auter space” constructed by Hatcher and Vogtmann in [J. London Math. Soc. (2) 58 (3) (1998) 633–655]. In more categorical language [Comment. Math. Helv. 73 (1998) 122–136], X n = E Aut(F n ) . This is useful because it allows one to compute (see, for example, [7,8]) the cohomology of normalizers or centralizers of finite subgroups of Aut(Fn) based on their actions on fixed point subcomplexes. The techniques used to prove it are largely those of Krstic and Vogtmann in [Comment. Math. Helv. 68 (1993) 216–262], who in turn used techniques similar to Culler and Vogtmann in [Invent. Math. 84 (1986) 91–119].
Developments in Luminescent Porous Si

The recent observation of room temperature photoluminescence (PL) from porous Si layers (PSLs) has received considerable attention. Bulk crystalline Si does not luminesce efficiently at room temperature due to the indirect nature of the energy bandgap minimum. The PL from PSLs has been attributed to quantum confinement effects in nanometer‐sized crystalline features found in PSLs, typically of high porosity. In this paper, we review some of the major results and discuss the controversies of subsequent research. The basic methods of fabricating luminescent PSLs are described, including conventional anodic etching and chemical etching. The latter technique requires no applied bias, but is modeled as an electrochemical process. Other processing issues are also addressed, particularly with respect to postanodization control of the PL spectrum. Microscopic and spectroscopic studies of the material and optical characteristics of PSLs fabricated by the various techniques are presented and discussed. The basic models for the luminescence mechanism are described, including quantum‐sized crystalline Si, surface passivation, , alloys, and molecular electronics. These models are discussed in terms of the supporting and contradicting evidence. Electroluminescence (EL) studies are discussed, including EL from anodic oxidation of PSLs as well as from light‐emitting diodes. The results are promising for optoelectronic applications. However, fundamental questions about the underlying chemistry, physics, and microstructure remain unanswered. More research will be required before any definitive statements can be conclusively made regarding the luminescence mechanism.
p-Methoxybenzyl ether cleavage by polymer-supported sulfonamides.

p-Methoxybenzyl ethers have been found to transfer from alcohols to sulfonamides in the presence of catalytic trifluoromethanesulfonic acid. This process for protecting group removal can be performed in solution with yields >94%. Through the use of sulfonamide-functionalized (“safety-catch”) resins, p-methoxybenzyl ethers can be cleaved in excellent yields with minimal purification.
Learning large-alphabet and analog circuits with value injection queries

We consider the problem of learning an acyclic discrete circuit with n wires, fan-in bounded by k and alphabet size s using value injection queries. For the class of transitively reduced circuits, we develop the Distinguishing Paths Algorithm, that learns such a circuit using (ns) O(k) value injection queries and time polynomial in the number of queries. We describe a generalization of the algorithm to the class of circuits with shortcut width bounded by b that uses (ns) O(k+b) value injection queries. Both algorithms use value injection queries that fix only O(kd) wires, where d is the depth of the target circuit. We give a reduction showing that without such restrictions on the topology of the circuit, the learning problem may be computationally intractable when s=n ?(1), even for circuits of depth O(log?n). We then apply our large-alphabet learning algorithms to the problem of approximate learning of analog circuits whose gate functions satisfy a Lipschitz condition. Finally, we consider models in which behavioral equivalence queries are also available, and extend and improve the learning algorithms of (Angluin in Proceedings of the Thirty-Eighth Annual ACM Symposium on Theory of Computing, pp. 584---593, 2006) to handle general classes of gate functions that are polynomial time learnable from counterexamples.
A simple function that requires exponential size read-once branching programs

Abstract We present a Boolean function in n variables that is computable in depth 2 monotone AC0 but requires 2 Ω(√n) size read-once branching programs. The function we consider is defined by the blocking sets of a finite projective plane.
Micro-earthquake monitoring with sparsely sampled data

Micro-seismicity can be used to monitor the migration of fluids during reservoir production and hydro-fracturing operations in brittle formations or for studies of naturally occurring earthquakes in fault zones. Micro-earthquake locations can be inferred using wave-equation imaging under the exploding reflector model, assuming densely sampled data and known velocity. Seismicity is usually monitored with sparse networks of seismic sensors, for example located in boreholes. The sparsity of the sensor network itself degrades the accuracy of the estimated locations, even when the velocity model is accurately known. This constraint limits the resolution at which fluid pathways can be inferred. Wavefields reconstructed in known velocity using data recorded with sparse arrays can be described as having a random character due to the incomplete interference of wave components. Similarly, wavefields reconstructed in unknown velocity using data recorded with dense arrays can be described as having a random character due to the inconsistent interference of wave components. In both cases, the random fluctuations obstruct focusing that occurs at source locations. This situation can be improved using interferometry in the imaging process. Reverse-time imaging with an interferometric imaging condition attenuates random fluctuations, thus producing crisper images which support the process of robust automatic micro-earthquake location. The similarity of random wavefield fluctuations due to model fluctuations and sparse acquisition is illustrated in this paper with a realistic synthetic example.
Do electrons change their c-axis kinetic energy upon entering the superconducting state?

The interlayer tunneling mechanism of the cuprate high temperature superconductors involves a conversion of the confinement kinetic energy of the electrons perpendicular to the CuO-planes (c-axis) in the normal state to the pair binding energy in the superconducting state. This mechanism is discussed and the arguments are presented from the point of view of general principles. It is shown that recent measurements of the c-axis properties support the idea that the electrons substantially lower their c-axis kinetic energy upon entering the superconducting state, a change that is nearly impossible in any conventional mechanism. The proper use of a c-axis conductivity sum rule is shown to resolve puzzles involving the penetration depth and the optical measurements.
Smoothed analysis of probabilistic roadmaps

The probabilistic roadmap algorithm is a leading heuristic for robot motion planning. It is extremely efficient in practice, yet its worst case convergence time is unbounded as a function of the input's combinatorial complexity. We prove a smoothed polynomial upper bound on the number of samples required to produce an accurate probabilistic roadmap, and thus on the running time of the algorithm, in an environment of simplices. This sheds light on its widespread empirical success.
Forecast Rationality Tests Based on Multi-Horizon Bounds

Forecast rationality under squared error loss implies various bounds on second moments of the data across forecast horizons. For example, the mean squared forecast error should be increasing in the horizon, and the mean squared forecast should be decreasing in the horizon. We propose rationality tests based on these restrictions, including new ones that can be conducted without data on the target variable, and implement them via tests of inequality constraints in a regression framework. A new test of optimal forecast revision based on a regression of the target variable on the long-horizon forecast and the sequence of interim forecast revisions is also proposed. The size and power of the new tests are compared with those of extant tests through Monte Carlo simulations. An empirical application to the Federal Reserve's Greenbook forecasts is presented.
‘Home’ base and monetary base rules: elementary evidence from the 1980s and 1990s ☆

Abstract This paper evaluates the quantitative importance of removing U.S. currency held abroad from the monetary base. We find that a simple macroeconometric model that uses home base has more explanatory power for changes in nominal income than when the total base is used. Moreover, proposed base rules for the conduct of monetary policy perform better when the model for home base is employed. The evidence from our elementary exercises suggests that accounting for foreign holdings of U.S. currency may be important in other contexts also.
Studies of backscattered sea return with a CW, dual-frequency, X-band radar

A coherent, CW, dual-frequency, X -band radar was used to study microwave sea return from the Chesapeake Bay. It is shown that the product of the backscattered fields depends strongly on long surface wave properties. In particular, a sharp line is found in the product power spectrum whose frequency is that of the water wave whose wavelength is in resonance with the spatial period of the beat frequency between the two transmitted signals and whose wave vector is parallel to the horizontal line of sight. Thus, gravity wave dispersion relations can be obtained with the system. Furthermore, the degree of modulation of short waves by long ones is given by the intensity of the line. A broad background corresponding to the convolution of the single-frequency Doppler spectra is also seen in the product power spectrum. These results are shown to be interpretable by composite surface scattering theory.
Invasion percolation of single component, multiphase fluids with lattice Boltzmann models

Abstract Application of the lattice Boltzmann method (LBM) to invasion percolation of single component multiphase fluids in porous media offers an opportunity for more realistic modeling of the configurations and dynamics of liquid/vapor and liquid/solid interfaces. The complex geometry of connected paths in standard invasion percolation models arises solely from the spatial arrangement of simple elements on a lattice. In reality, fluid interfaces and connectivity in porous media are naturally controlled by the details of the pore geometry, its dynamic interaction with the fluid, and the ambient fluid potential. The multiphase LBM approach admits realistic pore geometry derived from imaging techniques and incorporation of realistic hydrodynamics into invasion percolation models.
Wages, business cycles, and comparative advantage☆

Abstract The standard equilibrium models of business cycles face a puzzling fact that total hours vary greatly over the business cycle without much variation in aggregate wages. The model augments the standard RBC model to include Lucas span of control. Distinction between market and non-market and managerial and non-managerial work makes aggregate wages far less cyclical than individual wages. Cross-sectional comparative advantage between market and non-market sector in the workforce substantially increases the response of aggregate hours to shifts in relative productivity. As a result, the model provides a reconciliation between data and equilibrium macroeconomics.
A new and convenient synthesis of 2-amidofurans using the Jacobi bis-heteroannulation method

Abstract Cyclic 2-amidofurans were obtained using an intramolecular Diels-Alder reaction of 2-amido substituted oxazoles containing a tethered alkyne. This transformation represents a new route to this rare heterocyclic ring system.
Do eco-innovations harm productivity growth through crowding out? Results of an extended CDM model for Italy

Abstract This paper discusses the results for Italy of a CDM model ( Crepon et al., 1998 ) further extended with the objective of evaluating drivers and productivity effects of environmental innovations. The particular nature of environmental innovations, especially as regards the need of government intervention to create market opportunities, is likely to affect the way through which they are pursued (innovation equation within the CDM model) and their effect on productivity (productivity equation). The contribution of the paper is manifold. First, the drivers of environmental innovations (measured with environmental patents) are investigated by using mainly administrative data instead of survey data. Second, I investigate the extent to which firms with big polluting plants tend to bias their innovation strategies towards environmental technologies. Third, the return of environmental innovations is compared to the one of other innovations to indirectly assess the presence of a crowding out effect of environmental innovations at the expenses of other (possibly more profitable) innovations. Results, based on administrative data (AIDA by Bureau van Dijk and patent data from PATSTAT) of Italian manufacturing firms, show that innovation efforts of polluting firms is significantly biased towards environmental innovations and that environmental innovations tend to crowd out other more profitable (at least in the short run) innovations.
Exploiting Cell Dormancy and Load Balancing in LTE HetNets: Optimizing the Proportional Fairness Utility

We consider the problem of maximizing the proportional fairness (PF) system utility over heterogeneous wireless networks (HetNets) by jointly exploiting cell dormancy (cell ON–OFF)—wherein some transmission points from a set of interest can be made inactive—and load balancing (user association)—wherein users are associated to the active transmission points in that set, with each user being associated with only one point. We establish that this joint optimization problem, which is a discrete optimization problem, is NP-hard. Nevertheless, we prove that the load balancing subproblem for any given set of active transmission points is not NP-hard but instead can be reformulated as an asymmetric assignment problem and hence can be optimally solved in an efficient manner. In addition, we show that some generalized load balancing problems that incorporate multiuser diversity gains can also be optimally and efficiently solved. We propose another lower complexity greedy algorithm for the load balancing subproblem that offers a worst-case performance guarantee and describe a simple way to approximately realize a given input user association via biasing factors. We then derive low-complexity algorithms for the joint optimization problem, including one based on a successive approximation method that has hitherto been used for continuous nonconvex optimization problems. Simulations over an example Long-Term Evolution HetNet topology reveal the superior performance of the proposed algorithms and underscore the significant benefits of jointly exploiting cell dormancy and load balancing.
Combined wavelet video coding and error control for internet streaming and multicast

This paper proposes an integrated approach to Internet video streaming and multicast (e.g., receiver-driven layered multicast (RLM) by McCanne) based on combined wavelet video coding and error control. We design a packetized wavelet video (PWV) coder to facilitate its integration with error control. The PWV coder produces packetized layered bitstreams that are independent among layers while being embedded within each layer. Thus, a lost packet only renders the following packets in the same layer useless. Based on the PWV coder, we search for a multilayered error-control strategy that optimally trades off source and channel coding for each layer under a given transmission rate to mitigate the effects of packet loss. While both the PWV coder and the error-control strategy are new--the former incorporates embedded wavelet video coding and packetization and the latter extends the single-layered approach for RLM by Chou et al.--the main distinction of this paper lies in the seamless integration of the two parts. Theoretical analysis shows a gain of up to 1 dB on a channel with 20% packet loss using our combined approach over separate designs of the source coder and the error-control mechanism. This is also substantiated by our simulations with a gain of up to 0.6 dB. In addition, our simulations show a gain of up to 2.2 dB over previous results reported by Chou et al.
α-Chlorination of ketones using p-toluenesulfonyl chloride

Abstract Treatment of a variety of ketones with lithium diisopropylamide followed by p -toluenesulfonyl chloride gives α-chloroketones in good yields. In addition, a polymer tosyl chloride reagent has also been shown to effect this transformation.
A Vacuum Tube Voltage Regulator for Large Power Units

A new voltage regulator is described, suitable for large power units of standard construction. This regulator uses vacuum tubes as the controlling element, in place of vibrating contacts that have hitherto been employed. The voltage variation is less than 0.1 per cent when the load is gradually changed from no load to a little above full load. When this regulator is applied to d-c unit, some a-c source is necessary to supply the B-eliminator which is an essential part of it. The voltage of this a-c source, however, need be only fairly constant; it may safely vary by ± 3 volts (in the case of a 110-v source) without causing more than ± 0.1 per cent variation in the d-c line under regutlationt. When an a-c unit is to be regulated, on the other hand, the same unit may supply the B-eliminator.
Facile Synthesis of Chevrel Phase Nanocubes and Their Applications for Multivalent Energy Storage

Pure Cu2Mo6S8 nanocubes are prepared from a mixture of (NH4)2MoS4, CuCl2, and graphene in DMF (Ar, 90 °C, 4 h) followed by heating in reducing atmosphere (flowing 4% H2/Ar, 1000 °C, 7 h).
PREDICTION OF CONTACT MAPS USING SUPPORT VECTOR MACHINES

Contact map prediction is of great interest for its application in fold recognition and protein 3D structure determination. In this paper we present a contact-map prediction algorithm that employs Support Vector Machines as the machine learning tool and incorporates various features such as sequence profiles and their conservations, correlated mutation analysis based on various amino acid physicochemical properties, and secondary structure. In addition, we evaluated the effectiveness of the different features on contact map prediction for different fold classes. On average, our predictor achieved a prediction accuracy of 0.224 with an improvement over a random predictor of a factor 11.7, which is better than reported studies. Our study showed that predicted secondary structure features play an important roles for the proteins containing beta-structures. Models based on secondary structure features and correlated mutation analysis features produce different sets of predictions. Our study also suggests that models learned separately for different protein fold families may achieve better performance than a unified model.
Mixing Time Bounds via the Spectral Profile

On complete, non-compact manifolds and infinite graphs, Faber-Krahn inequalities have been used to estimate the rate of decay of the heat kernel. We develop this technique in the setting of finite Markov chains, proving upper and lower $L^{\infty}$ mixing time bounds via the spectral profile. This approach lets us recover and refine previous conductance-based bounds of mixing time (including the Morris-Peres result), and in general leads to sharper estimates of convergence rates. We apply this method to several models including groups with moderate growth, the fractal-like Viscek graphs, and the product group $Z_a \times Z_b$, to obtain tight bounds on the corresponding mixing times.
Nucleate Pool Boiling over Vertical Steps

Nucleate subcooled pool boiling of water over vertical steps was carried out under atmospheric conditions. Two forward-facing steps of 0.8125 and 0.50 in. were considered. Data were statistically analyzed to determine samplingerror.Theebullitionwasqualitativelyexplainedintermsofthermal/e owe eldsandbubbledynamics.Plots of boiling heat e ux vs superheat and surface heat transfer coefe cient vs heat e ux have been provided. Empirical correlations, developed from the above-mentioned data, are also presented. Boiling on vertically extended surfaces showed an increase in heat e ux for a given superheat when compared with a plain vertical surface because of e uid agitation in the region of the step. The parameters associated with bubble dynamics and bubble interactions were also qualitatively discussed. Nomenclature C = correlation constant h = surface heat transfer coefe cient, kW/m 2 K n = exponential constant q = ebullition heat e ux, kW/m 2 T = temperature, K Subscripts p = pool conditions w = wall conditions
The Inventory–Sales Relationship in the Market for New Single‐Family Homes

Time series methods are applied to study monthly inventory and sales dynamics in the U.S. market for new single-family homes. The inventory measure used is the inventory of unsold, new single-family homes, regardless of the stage of construction. Stylized facts regarding inventory, sales, the inventory–sales ratio and the implied series of speculative housing starts are produced. Implications for structural models of housing supply and the relationship of inventory investment in this market to economy-wide inventory investment are considered. Finally, innovation accounting methods are applied to a structural VAR to study the responses of inventories and sales to permanent and transitory shocks.
On the linear stability of weakly ionized, magnetized planar shear flows

We investigate the effects of ambipolar diffusion and the Hall effect on the stability of weakly ionized, magnetized planar shear flows. Employing a local approach similar to the shearing-sheet approximation, we solve for the evolution of linear perturbations in both streamwise-symmetric and non-streamwise-symmetric geometries using Wentzel-Kramers-Brillouin techniques and/or numerical methods. We find that instability arises from the combination of shear and non-ideal magnetohydrodynamic processes and is a result of the ability of these processes to influence the free energy path between the perturbations and the shear. They turn what would be simple linear-in-time growth due to current and vortex stretching from shear into exponentially growing instabilities. Our results aid in understanding previous work on the behaviour of weakly ionized accretion discs. In particular, the recent finding that the Hall effect and ambipolar-diffusion destabilize both positive and negative angular velocity gradients acquires a natural explanation in the more general context of this paper. We construct a simple toy model for these instabilities based upon transformation operators (shears, rotations and projections) that captures both their qualitative and, in certain cases, exact quantitative behaviour.
Backward error analysis for multisymplectic discretizations of Hamiltonian PDEs

Several recently developed multisymplectic schemes for Hamiltonian PDEs have been shown to preserve associated local conservation laws and constraints very well in long time numerical simulations. Backward error analysis for PDEs, or the method of modified equations, is a useful technique for studying the qualitative behavior of a discretization and provides insight into the preservation properties of the scheme. In this paper we initiate a backward error analysis for PDE discretizations, in particular of multisymplectic box schemes for the nonlinear Schrodinger equation. We show that the associated modified differential equations are also multisymplectic and derive the modified conservation laws which are satisfied to higher order by the numerical solution. Higher order preservation of the modified local conservation laws is verified numerically.
Numerical analysis of aerodynamic performance of rotors with leading edge slats

A three dimensional compressible Navier-Stokes analysis capable of computing flows around wings and rotors with partial-span flaps or slats is described. This analysis is cast in a moving body-fitted coordinate system permitting arbitrary motion of the solid surfaces to be directly modeled. This methodology is validated through several single and multi-element rotor and wing configurations. The analysis is subsequently applied to two helicopter rotors. The effects of leading edge slats on the aerodynamic performance of these rotors in hover is studied. It is demonstrated that leading edge slats can significantly improve the hover performance at high pitch settings, with an increase in thrust and a reduction in torque. At low pitch settings, the slats were found to be detrimental to the rotor performance. Many practical issues such as surface imperfections, proper sealing of the slat during retraction, control loads and other implementation aspects should be carefully evaluated in the event of a practical design of a slat. However, in the present study only the aerodynamic effects of slats are addressed and no practical issues are considered.