cssi/SciSciGPT-SciSciNet huggingface dataset:
Investigation of surfactant-enhanced mass removal and flux reduction in 3D correlated permeability fields using magnetic resonance imaging.

Abstract Magnetic resonance imaging (MRI) was used to visualize the NAPL source zone architecture before and after surfactant-enhanced NAPL dissolution in three-dimensional (3D) heterogeneously packed flowcells characterized by different longitudinal correlation lengths: 2.1 cm (aquifer 1) and 1.1 cm (aquifer 2). Surfactant flowpaths were determined by imaging the breakthrough of a paramagnetic tracer (MnCl 2 ) analyzed by the method of moments. In both experimental aquifers, preferential flow occurred in high permeability materials with low NAPL saturations, and NAPL was preferentially removed from the top of the aquifers with low saturation. Alternate flushing with water and two surfactant pulses (5–6 pore volumes each) resulted in ∼ 63% of NAPL mass removal from both aquifers. However, overall reduction in mass flux (Mass Flux 1) exiting the flowcell was lower in aquifer 2 (68%) than in aquifer 1 (81%), and local effluent concentrations were found to increase by as high as 120 times at local sampling ports from aquifer 2 after surfactant flushing. 3D MRI images of NAPL revealed that NAPL migrated downward and created additional NAPL source zones in previously uncontaminated areas at the bottom of the aquifers. The additional NAPL source zones were created in the direction transverse to flow in aquifer 2, which explains the higher mass flux relative to aquifer 1. Analysis using a total trapping number indicates that mobilization of NAPL trapped in the two coarsest sand fractions is possible when saturation is below 0.5 and 0.4, respectively. Results from this study highlight the potential impacts of porous media heterogeneity and NAPL source zone architecture on advanced in-situ flushing technologies.
Systolic implementations of a move-to-front text compressor

We give systolic implementations for three variants of the move-to-front coding algorithm discussed in recent journal articles by Ryabko, Elias, and Bentley, Sleator, Tarjan, and Wei. Our intent is to make a simple high-speed text-compression system for both data transmission and data storage devices. Comparing our implementations with previously-proposed software and hardware devices for these applications, we conclude that our implementations should operate at much higher bandwidth than any known high-compression algorithm, and at higher bandwidth and comparable compression to the Lempel-Ziv-Welch and Smith-Storer hardware.
Synthesis of enantioenriched 4-thiazolidinone (−)-LY213829 by chemoselective benzylamide cleavage in the presence of a C-S bond

Abstract ( R )-2-Methylbenzylamine has been used to covalently “resolve” thiol acid 7 and assemble 4-thiazolidinone 8a in one step. Selective deprotection of the 2-methylbenzylamide using lithium in ammonia/THF has been achieved in the presence of a readily hydrogenolyzed C-S bond. Enantioenriched (−)-LY213829 ( 1 ) of 98% ee has been prepared by this five step route in 25% yield from aldehyde 2 .
Dynamics of Type-3 Wind Turbine Generator Models

The influence of wind turbine generators (WTGs) on power system dynamic performance is becoming increasingly important as wind generation grows. The dynamic behavior of WTGs should therefore be thoroughly understood. The paper analyzes dynamic models of type-3 WTGs, and in particular the WECC generic model. The behavior of such models is governed by interactions between the continuous dynamics of state variables, and discrete events associated with limits. It is shown that these interactions can be quite complex, and may lead to switching deadlock that prevents continuation of the trajectory. Switching hysteresis is proposed for eliminating deadlock situations. Various type-3 WTG models include control blocks that duplicate integrators. It is shown that this leads to non-uniqueness in the conditions governing steady-state, and may result in pre- and post-disturbance equilibria not coinciding. It also gives rise to a zero eigenvalue in the linearized WTG model.
Higher spin gauge theory and holography: the three-point functions

In this paper we calculate the tree level three-point functions of Vasiliev's higher spin gauge theory in AdS4 and find agreement with the correlators of the free field theory of N massless scalars in three dimensions in the O(N) singlet sector. This provides substantial evidence that Vasiliev theory is dual to the free field theory, thus verifying a conjecture of Klebanov and Polyakov. We also find agreement with the critical O(N) vector model, when the bulk scalar field is subject to the alternative boundary condition such that its dual operator has classical dimension 2.
Enantioselective Rhodium-Catalyzed [4 + 2] Cycloaddition of α,β-Unsaturated Imines and Isocyanates

A [4+2] cycloaddition of α,β-unsaturated imines and isocyanates catalyzed by a phosphoramidite-rhodium complex provides pyrimidinones in good yields and high enantioselectivities.
Catalytic Cu(I) assisted polyfunctionalization of zirconacyclopentenes

Abstract Using a catalytic quantity of CuCl•2LiCl, zirconacyclopentenes can be regiospecifically transmetallated and subsequently induced to undergo 1,4-additions to enones. Further manipulations of the presumed zirconium enolates are also presented, including three- and four-component couplings.
CHEMISTRY OF SILICATE ATMOSPHERES OF EVAPORATING SUPER-EARTHS

We model the formation of silicate atmospheres on hot volatile-free super-Earths. Our calculations assume that all volatile elements such as H, C, N, S, and Cl have been lost from the planet. We find that the atmospheres are composed primarily of Na, O2, O, and SiO gas, in order of decreasing abundance. The atmospheric composition may be altered by fractional vaporization, cloud condensation, photoionization, and reaction with any residual volatile elements remaining in the atmosphere. Cloud condensation reduces the abundance of all elements in the atmosphere except Na and K. We speculate that large Na and K clouds such as those observed around Mercury and Io may surround hot super-Earths. These clouds would occult much larger fractions of the parent star than a closely bound atmosphere, and may be observable through currently available methods.
Dispersive Estimates for Manifolds with One Trapped Orbit

For a large class of complete, non-compact Riemannian manifolds, (M, g), with boundary, we prove high energy resolvent estimates in the case where there is one trapped hyperbolic geodesic. As an ap...
Microwave spectrum, structure, and quadrupole coupling for the ethylene-hydrogen cyanide complex

Microwave spectra for the complexes ethylene–HCN and ethylene–DCN were observed with the pulsed beam, Fourier transform spectrometer. The complexes are ‘‘T’’ shaped with the HCN hydrogen atom adjacent to the C–C double bond of ethylene. The HCN molecule lies on a line perpendicular to the plane of ethylene and passing through the ethylene center of mass. The HCN carbon atom is 3.702(10) A above the ethylene plane. The nitrogen quadrupole coupling strength is eQqaa(N)=−4.363(2) MHz for ethylene–HCN and eQqaa(N)=−4.396(3) MHz for ethylene–DCN. The deuterium quadrupole coupling strength is eQqaa(D)=0.178(7) MHz for ethylene–DCN. The anisotropy in the nitrogen quadrupole coupling eQ(qbb−qcc)(N) is 0.013(3) MHz for ethylene–HCN and 0.047(12) MHz for ethylene–DCN. The rotational constants are Centrifugal distortion constants DJ and DJK were obtained.
A Cheeger Inequality for the Graph Connection Laplacian

The $O(d)$ synchronization problem consists of estimating a set of $n$ unknown orthogonal $d\times d$ matrices $O_1,\ldots,O_n$ from noisy measurements of a subset of the pairwise ratios $O_iO_j^{-1}$. We formulate and prove a Cheeger-type inequality that relates a measure of how well it is possible to solve the $O(d)$ synchronization problem with the spectra of an operator, the graph connection Laplacian. We also show how this inequality provides a worst-case performance guarantee for a spectral method to solve this problem.
A search memory subsystem for a general-purpose computer

The search memory provides an extremely powerful tool for data-processing applications in which files of data are manipulated---applications such as data correlation, information retrieval and data analysis. For many such problems, a moderate size search memory can increase the performance of a general-purpose computer by several orders of magnitude. This paper describes the system design of a search memory subsystem integral to a general-purpose computer. The unit will operate in much the same manner as a conventional arithmetic unit, receiving data directly from the main memory, and placing the results of a search in the accumulator. This generalized design is independent of the particular magnetic memory element used and is not constrained by any particular computer organization. However, values have been assigned to the various parameters in the system so that the concepts can be concretely described. The techniques and concepts presented in this paper are the result of a company-sponsored program. The following sections present an assumed general-purpose computer structure, the design of a search memory subsystem, and possible implementation. Appendix A presents the basic principles of the search memory organization.
Fully-Integrated On-Chip DC-DC Converter With a 450X Output Range

This paper presents a technique to efficiently supply power over a wide power range using a fully-integrated on-chip converter for dynamic voltage scaling (DVS) based applications. All components, including filter elements, are integrated on-chip. To achieve high efficiency the converter adaptively switches between different modes of operation by detecting the output current. The design, implemented in IBM 130 nm CMOS technology, achieves a peak efficiency of 77% at reduced temperature of 8°C and has a maximum efficiency of 74.5% under normal operating conditions. The converter supplies power over a 450X output power range (0.6 mW to 266 mW). To the best of our knowledge, this is the largest reported power range for a high-efficiency, fully-integrated on-chip power converter to date.
tert-Butyldimethylsilyl ethers of phenols: Their one-step conversion to benzyl or methyl ethers and utility in regioselective ortho lithiation

Abstract A new method for the one-step conversion of tert -butyldimethylsilyl ethers of phenols to benzyl or methyl ethers and the blocking effect of the tert -butyldimethylsilyloxy group in regioselective ortho lithiation are described.
Defect profiling in elemental and multilayer systems: correlations of fitted defect concentrations with positron implantation profiles

Abstract The results of several positron annihilation (Doppler broadening) experiments have been analyzed using the BNL Monte Carlo implantation profiles and the program VEPFIT. The program VEPFIT has been modified so that scaled, parameterized multilayer profiles can also be used as the initial condition for the diffusion equation solution. We have looked at both elemental (e.g. amorphous silicon) and multilayer (e.g. Pd Si ) systems. Strong correlations between the input implantation profile parameters and the fitted values obtained for the diffusion lengths and overlayer thicknesses for the multilayer systems have been found. The effect of uncertainties in the mean depth on the value of the diffusion length and hence the defect concentrations will be discussed. The impact of reimplanting backscattered positrons on both the implantation profiles and the fitted diffusion lengths will also be presented.
Fast deterministic consensus in a noisy environment

It is well known that the consensus problem cannot be solved deterministically in an asynchronous environment, but that randomized solutions are possible. We propose a new model, called noisy scheduling, in which an adversarial schedule is perturbed randomly, and show that in this model randomness in the environment can substitute for randomness in the algorithm. In particular, we show that a simplified, deterministic version of Chandra's wait-free shared-memory consensus algorithm [Chandra, in: Proceedings of the Fifteenth Annual ACM Symposium on Principles of Distributed Computing, Philadelphia, PA, USA, 23-26 May, 1996, pp. 166-175] solves consensus in time at most logarithmic in the number of active processes. The proof of termination is based on showing that a race between independent delayed renewal processes produces a winner quickly. In addition, we show that the protocol finishes in constant time using quantum and priority-based scheduling on a uniprocessor, suggesting that it is robust against the choice of model over a wide range.
Exposure to risk factors for ulcerative colitis occurs during an early period of life.

Abstract OBJECTIVE: It has been speculated that environmental factors play a role in the etiology of ulcerative colitis. A previous analysis revealed that the time trends of ulcerative colitis in England were shaped by an underlying birth-cohort pattern. We undertook this study to test whether the birth-cohort pattern was a unique feature of the English vital statistics or whether a similar phenomenon could also be ascertained in the mortality statistics from a different country, such as Switzerland. Besides comparing the data of ulcerative colitis from Switzerland and England, the trends of ulcerative colitis were compared with those of gastric and duodenal ulcer. METHODS: Death rates from ulcerative colitis, gastric ulcer, and duodenal ulcer were plotted against the period of death and period of birth. An age-standardized cohort mortality ratio was calculated as a summary statistic of the overall mortality associated with each consecutive birth-cohort. RESULTS: Mortality from ulcerative colitis increased among successive generations born throughout the 19th century. It peaked in individuals born around 1890 and has declined since then. Strikingly similar patterns were found in Switzerland and England. The birth-cohort pattern underlying the time trends of ulcerative colitis applied equally to the data for women and men. In comparison with peptic ulcer, the birth-cohort pattern of ulcerative colitis was almost identical to that of duodenal ulcer. It peaked in both countries 10–20 yr later than gastric ulcer. CONCLUSIONS: The birth-cohort pattern indicates that acquisition of ulcerative colitis is strongly influenced by environmental risk factors and that the exposure to these factors occurs during an early period of life. The similarity in the birth-cohort patterns of duodenal ulcer and ulcerative colitis could hint at a childhood infection or a related mode of transmission in both diseases.
Resonant Orbits in Triaxial Galaxies

Box orbits in triaxial potentials are generically thin, that is, they lie close in phase space to a resonant orbit satisfying a relation of the form lω1 + mω2 + nω3 = 0 between the three fundamental frequencies. Resonant orbits are confined for all time to a membrane in configuration space; they play roughly the same role in structuring the phase space of three-dimensional systems that periodic orbits play in two dimensions. Stable resonant orbits avoid the center of the potential; orbits that are thick enough to pass near the destabilizing center are typically stochastic. Resonances in triaxial potentials are most important at energies far outside the region of gravitational influence of a central black hole. Near the black hole, the motion is essentially regular, although resonant orbits exist in this region as well, including at least one family whose elongation is parallel to the long axes of the triaxial figure.
The Role of Conventional MR and CT in the Work-Up of Dementia Patients

Dementia is a clinical syndrome with many causes. There often is overlap in the clinical manifestations of various forms of dementia, making them difficult to categorize. Neuroimaging can play an important role in distinguishing one form of dementia from another. Advanced imaging techniques continue to provide greater insight into the underlying pathologic processes in patients who have dementia. Conventional MRI and CT, however, still can contribute useful information when interpreting radiologists are familiar with the patterns of volume loss and signal or density changes that are characteristic of various forms of dementia.
Down–Up Algebras

Abstract The algebra generated by the down and up operators on a differential or uniform partially ordered set (poset) encodes essential enumerative and structural properties of the poset. Motivated by the algebras generated by the down and up operators on posets, we introduce here a family of infinite-dimensional associative algebras called down–up algebras. We show that down–up algebras exhibit many of the important features of the universal enveloping algebraU( s l2) of the Lie algebra s l 2including a Poincare–Birkhoff—Witt type basis and a well-behaved representation theory. We investigate the structure and representations of down–up algebras and focus especially on Verma modules, highest weight representations, and category O modules for them. We calculate the exact expressions for all the weights, since that information has proven to be particularly useful in determining structural results about posets.
Frequency-weighted model reduction with L ∞ error bounds

Abstract This paper considers frequency-weighted model reduction. The explicit lower and upper approximation error bounds are derived for certain classes of weighted model reduction problems. The approximation is based on some unweighted approximations and the error bounds are given in terms of the Hankel singular values of the weighted model.
Use of the non-aldol aldol process in the synthesis of the C1–C11 fragment of the tedanolides: use of lactol ethers in place of tetrahydrofurans

Abstract The use of a lactol methyl ether 23 in place of the simple tetrahydrofuran 11 allows for the high yielding non-aldol aldol process to occur without concomitant tetrahydropyran formation (cf. 13) to give the desired product 24 in good yield.
Do Wealth Gains from Land Appreciation Cause Farmers to Expand Acreage or Buy Land

Recent increases in farm real estate values in the United States have increased farm equity. By exploiting periods of high and low appreciation that caused various increases in wealth for farmers owning various shares of their farmland, we examine whether U.S. grain farmers expanded their acres harvested or acres owned in response to an increase in their land wealth. We find that land wealth had little effect on farm size. However, for similarly-sized farms, a larger ownership share (10 percentage points) led to an increase in the growth of land owned (2 percentage points). Because older farmers own more of the land that they farm, greater land appreciation slows the rate at which younger farmers acquire land relative to older farmers.
Open string thermodynamics and D-branes

Abstract We study the thermodynamics of open superstrings in the presence of p-dimensional D-branes. mWe get some finite temperature dualities relating the one-loop canonical free energy of open strings to the self-energy of D-branes at dual temperature. For the open bosonic string the inverse dual temperature is, as expected, the dual length under T-duality, 4π 2 α′ β . On the contrary, for the SO(N), type-I superstring the dual temperature is given by β-duality, 2π 2 α′ β . We also study the emergence of the Hagedorn singularity in the dual description as triggered by the coupling of the D-brane to unphysical tachyons as well as the high temperature limit.
Efficient Time Bars: A New Rationale for the Existence of Statutes of Limitations in Criminal Law

Abstract This paper proposes a novel normative economic explanation for statutes of limitations for criminal offenses. Because potential criminals tend to discount the future at higher rates than society, punishing crimes long after they are committed will be inefficient. Punishments after a long lag have only a nominal deterrent effect, while they may cost society substantial sums. The model presented in the paper derives the optimal statute of limitations for a crime by modifying the standard model of public enforcement of law to consider lags between crime and punishment. In addition, numerical simulations of the model suggest that some U.S. statutes of limitations are generally consistent with optimal limitations (probably serendipitously). Finally, the paper employs the model to critique several tenets of the law concerning statutes of limitations.
Hot-wire chemical vapor deposition for epitaxial silicon growth on large-grained polycrystalline silicon templates

Abstract We investigate low-temperature epitaxial growth of thin silicon films by HWCVD on Si [1 0 0] substrates and polycrystalline template layers formed by selective nucleation and solid phase epitaxy (SNSPE). We have grown 300-nm thick epitaxial layers at 300 °C on silicon [1 0 0] substrates using a high H2:SiH4 ratio of 70:1. Transmission electron microscopy confirms that the films are epitaxial with a periodic array of stacking faults and are highly twinned after approximately 240 nm of growth. Evidence is also presented for epitaxial growth on polycrystalline SNSPE templates under the same growth conditions.
Facile Cu-free Sonogashira cross-coupling of nucleoside C-6 arylsulfonates with terminal alkynes

Abstract The combination of PdCl 2 [CH 3 CN] 2 with XPhos is an efficient catalytic system for the Sonogashira-type cross-coupling of 2′-deoxyguanosine O 6 -arylsulfonates with terminal alkynes. The reactions generally proceed under mild conditions requiring no Cu co-catalyst to give the corresponding C-6-alkynylated deoxynucleosides in moderate to good yields.
A DIGITAL LOGIC NANOWIRE FOR RELIABILITY ENHANCEMENT

Due to the many random factors from thermal fluctuations to wave interference, computational perfection in nanoICs is difficult to achieve. Defects and faults arise from instability and noise proness of nanoICs, which lead to unreliable results. A probabilistic computational model is needed to reduce such errors and to achieve more reliable computation. The probabilities of the outputs of this model can be calculated by the arithmetic expressions of the Boolean functions. This paper presents a method for transforming a low noisy reliability nanocircuit into a high reliability nanocircuit without using any hardware redundancy techniques. A class of nanocircuits, called reliability enhancement nanocircuits (RENC) is introduced. Each RENC is a simple logic circuit with a single input and output. It is shown that with a proper setting of the "logic threshold value" of the RENC, which determines logic value 0 or 1 for the input and output, the output (reliability) of RENC can be higher than its input reliability. Thus, when a RENC is connected to an output of a nanocircuit, the reliability of the entire circuit can be enhanced. A reliability enhancement nanowire (RENW) can be formed by cascading n number RENCs. It is also shown that by connecting each output of a low reliability nanocircuit with a RENW with sufficient number of RENCs , the reliability of the nanocircuit can be raised to any desirable higher level. This method is illustrated by examples and is applicable to any digital nanocircuit design using any nanotechnology.
3D tumor localization through real-time volumetric x-ray imaging for lung cancer radiotherapy.

Purpose : To evaluate an algorithm for real-time 3D tumor localization from a single x-ray projection image for lungcancerradiotherapy. Methods : Recently, we have developed an algorithm for reconstructing volumetric images and extracting 3D tumor motion information from a single x-ray projection [Liet al., Med. Phys. 37, 2822–2826 (2010)]. We have demonstrated its feasibility using a digital respiratory phantom with regular breathing patterns. In this work, we present a detailed description and a comprehensive evaluation of the improved algorithm. The algorithm was improved by incorporating respiratory motion prediction. The accuracy and efficiency of using this algorithm for 3D tumor localization were then evaluated on (1) a digital respiratory phantom, (2) a physical respiratory phantom, and (3) five lungcancer patients. These evaluation cases include both regular and irregular breathing patterns that are different from the training dataset. Results : For the digital respiratory phantom with regular and irregular breathing, the average 3D tumor localization error is less than 1 mm which does not seem to be affected by amplitude change, period change, or baseline shift. On an NVIDIA Tesla C1060 graphic processing unit (GPU) card, the average computation time for 3D tumor localization from each projection ranges between 0.19 and 0.26 s, for both regular and irregular breathing, which is about a 10% improvement over previously reported results. For the physical respiratory phantom, an average tumor localization error below 1 mm was achieved with an average computation time of 0.13 and 0.16 s on the same graphic processing unit (GPU) card, for regular and irregular breathing, respectively. For the five lungcancer patients, the average tumor localization error is below 2 mm in both the axial and tangential directions. The average computation time on the same GPU card ranges between 0.26 and 0.34 s. Conclusions : Through a comprehensive evaluation of our algorithm, we have established its accuracy in 3D tumor localization to be on the order of 1 mm on average and 2 mm at 95 percentile for both digital and physical phantoms, and within 2 mm on average and 4 mm at 95 percentile for lungcancer patients. The results also indicate that the accuracy is not affected by the breathing pattern, be it regular or irregular. High computational efficiency can be achieved on GPU, requiring 0.1–0.3 s for each x-ray projection.
Pulsed Electrodeposition of Ni‐Mo Alloys

The effect of pulsing the current on the composition, the internal stress, and mechanical properties of Ni-Mo electrodeposits was investigated. The molybdenum, content increased with increasing peak current density and to a lesser degree with decreasing duty cycle. A reduction in the internal stresses was explained in terms of the relaxation of those due to crystallite or fine grain coalescence during the off-time and an expansion of the surface layer when hydrogen diffused into it at the start of each on-time. The mechanical properties were improved by high frequency pulse plating. Deposits consisting of alternate layers of different composition annealed at 300/sup 0/C exhibited further improvement of their mechanical properties.
Theory of catalysis of nucleation by surface patches

Abstract By hypothesizing a plausible distribution of units for crystal nucleation with respect_to size, and that the size of the units may be of the order of the critical size for growth of a nucleus into a super-cooled liquid, the multiplicity in crystal nucleation frequency sometimes observed for the isothermal solidification of small droplets is accounted for with the use of no more than two fundamental frequencies. The theory satisfactorily explains the athermal nucleation of crystals for the solidification of small mercury droplets that have “HgX” patches on their surface.
Transient electromagnetic responses of high-contrast prisms in a layered earth

A numerical solution has been developed for transient electromagnetic (TEM) responses of prisms in a layered host. The solution is based on the method of integral equations, where the prisms are replaced with an equivalent scattering current. This scattering current is approximated with pulse and divergence-free basis functions. The divergence-free functions model eddy currents closed in the prisms, and hence simulate the inductive responses of the prisms in a very resistive host. Checks on the solution show that it is valid for conductive and resistive hosts, including a free-space host. The masking effect of conductive overburden is shown to delay and suppress the three-dimensional (3-D) TEM response of a conductor. After the overburden response is removed, an interpretation of the conductor with free-space models is a poor approximation when the basement rock is conductive. Instead of an exponential decay at late times, the conductor's response decays as an inverse power law. When the basement resistivity is increased, the conductor exhibits an exponential decay at late times. We have used the solution to gain interpretational insight into the lateral resolution of multiple conductors with different TEM surveys. The resolution of multiple conductors is very poor in a fixed-loop survey, but in a central-loop survey the resolution is better, provided the data are interpreted at early times. At later times, multiple conductors may not be resolvable and interpretational ambiguities could arise in a central-loop survey.
Site competition effect of impurities and grain boundary stability in iron and tungsten

Fe-base alloys and W are among the most important ultra-high-strength materials. The purpose of this paper is to elucidate the energetics of impurities in Fe and W GBs, and analyze the effect of impurities on the intergranular cohesion at the electron-atom level. A deeper understanding of the cohesion-decohesion processes on the microscopic level will lay a foundation for a 'smart design' of more ductile and tough alloys. In particular, the theoretical analysis of the electron structure and the energetics of Fe and W GBs, both clean (CL) and with impurities, enables one to make important predictions. The calculations have shown that impurities, such as N, O, P, S, Si weaken the intergranular cohesion resulting in 'loosening' of the GBs in Fe and W. The presence of B on the contrary, enhances the interatomic interaction across the GB. The so-called 'site-competition effect' should play an important role affecting impurity distribution in GBs. Among the impurities analyzed, both in Fe and W, B in the GB has the lowest energy, and thus would tend to push other impurity atoms off the GB, thus improving resistance to brittle fracture.
The effects of mixing of the ejecta on the hard X-ray emissions from SN 1987A

The X-ray and gamma-ray emissions expected from SN 1987A have been calculated, taking into account mixing of material in the ejecta. Nuclear gamma rays emitted by Co-56 are scattered down to the hard X-ray band by multiple Compton scatterings. Nomoto's 11E1Y6 model for the ejecta of SN 1987A is used. X-ray light curves in the 10-30 keV band and spectra above 20 keV calculated with an inner mixed region of 5 + or - 1 solar mass are consistent with the observations performed with the Ginga satellite and the Kvant/Roentgen mission. On the basis of this comparison, further evolutions of the hard X-ray, gamma-ray, and optical/infrared emissions are discussed.
Inelastic Electron-Proton and γ-Proton Scattering and the Structure of the Nucleon

A model for highly inelastic electron-nucleon scattering at high energies is studied and compared with existing data. This model envisages the proton to be composed of pointlike constituents (“partons”) from which the electron scatters incoherently. We propose that the model be tested by observing ϒ rays scattered inelastically in a similar way from the nucleon. The magnitude of this inelastic Compton-scattering cross section can be predicted from existing electron-scattering data, indicating that the experiment is feasible, but difficult, at presently available energies.
Are There Rational Speculative Bubbles in REITs

This study tests for the presence of rational speculative bubbles in the Equity REIT industry. We analyze REIT prices using a vector of macroeconomic fundamentals. Using the unit root test and cointegration procedures, we find no evidence of rational bubbles in the REIT market. Tests for duration dependence in the returns series show no evidence of negative duration dependence, suggesting that REIT markets are not affected by rational bubbles. Applying the same tests, we find no evidence of rational speculative bubbles in the Russell 2000 index, a proxy for small-cap stocks.
Radiation Hardened 64-BIT CMOS/SOS RAM

Radiation hardening procedures have been implemented in design, analysis and fabrication of a 64-bit CMOS/SOS RAM. The resultant circuit is a moderately complex (714 transistor), dielectrically isolated integrated circuit which features high performance and high radiation tolerance. Typical electrical parameters include 120 nsec read-access time and 1?watt/bit standby power dissipation. The SOS construction minimizes radiation-induced transient photocurrents while a hardened gate insulator provides immunity to total dose effects. Transient radiation upset levels exceed 3 × 1010 rads(Si)/sec for short (? 50 ns) pulses and ionizing dose hardness exceeds 106 rads(Si). A neutron fluence of 3.65 × 1014 n/cm2 had no effect on circuit operation beyond that expected from the ionizing radiation alone.
Radial Velocities of Three Poorly Studied Clusters and the Kinematics of Open Clusters

We present radial velocities for stars in the field of the open star clusters Berkeley 44, Berkeley 81, and NGC?6802 from spectra obtained using the Wisconsin-Indiana-Yale-NOAO (WIYN) 3.5?m telescope. These clusters are of intermediate age (1-3?Gyr), located within the solar Galactocentric radius, and have no previous radial velocity measurements. We find mean radial velocities of ?9.6?? 3.0?km?s?1, 48.1 ??2.0?km?s?1, and 12.4 ??2.8?km?s?1 for Be 44, Be 81, and NGC?6802, respectively. We present an analysis of radial velocities of 134 open clusters of a wide range of ages using data obtained in this study and the literature. Assuming the system of clusters rotates about the Galactic center with a constant velocity, we find older clusters exhibit a slower rotation and larger line-of-sight (LOS) velocity dispersion than younger clusters. The gradual decrease in rotational velocity of the cluster system with age is accompanied by a smooth increase in LOS velocity dispersion, which we interpret as the effect of heating on the open cluster system over time.
A sharp inverse Littlewood-Offord theorem

Let ηi,i = 1,…,n be iid Bernoulli random variables. Given a multiset vof n numbers v1,…,vn, the concentration probability P1(v) of v is defined as P1(v) := supxP(v1η1+ …vnηn = x). A classical result of Littlewood–Offord and Erdos from the 1940s asserts that if the vi are nonzero, then this probability is at most O(n-1-2). Since then, many researchers obtained better bounds by assuming various restrictions on v. In this article, we give an asymptotically optimal characterization for all multisets v having large concentration probability. This allow us to strengthen or recover several previous results in a straightforward manner. © 2010 Wiley Periodicals, Inc. Random Struct. Alg., 2010
The Chandra Deep Field North Survey. XIII. 2 Ms Point-Source Catalogs

We present point-source catalogs for the ?2 Ms exposure of the Chandra Deep Field North, currently the deepest X-ray observation of the universe in the 0.5?8.0 keV band. Five hundred and three (503) X-ray sources are detected over an ?448 arcmin2 area in up to seven X-ray bands. Twenty (20) of these X-ray sources lie in the central ?5.3 arcmin2 Hubble Deep Field North (13,600 sources deg-2). The on-axis sensitivity limits are ?2.5 ? 10-17 ergs cm-2 s-1 (0.5?2.0 keV) and ?1.4 ? 10-16 ergs cm-2 s-1 (2?8 keV). Source positions are determined using matched-filter and centroiding techniques; the median positional uncertainty is ?03. The X-ray colors of the detected sources indicate a broad variety of source types, although absorbed AGNs (including a small number of possible Compton-thick sources) are clearly the dominant type. We also match lower significance X-ray sources to optical counterparts and provide a list of 79 optically bright (R 23) lower significance Chandra sources. The majority of these sources appear to be starburst and normal galaxies. The average backgrounds in the 0.5?2.0 keV and 2?8 keV bands are 0.056 and 0.135 counts Ms-1 pixel-1, respectively. The background count distributions are very similar to Poisson distributions. We show that this ?2 Ms exposure is approximately photon limited in all seven X-ray bands for regions close to the aim point, and we predict that exposures up to ?25 Ms (0.5?2.0 keV) and ?4 Ms (2?8 keV) should remain nearly photon limited. We demonstrate that this observation does not suffer from source confusion within ?6' of the aim point, and future observations are unlikely to be source-confusion limited within ?3' of the aim point even for source densities exceeding 100,000 deg-2. These analyses directly show that Chandra can achieve significantly higher sensitivities in an efficient, nearly photon-limited manner and be largely free of source confusion. To allow consistent comparisons, we have also produced point-source catalogs for the ?1 Ms Chandra Deep Field South (CDF-S). Three hundred and twenty-six (326) X-ray sources are included in the main Chandra catalog, and an additional 42 optically bright X-ray sources are included in a lower significance Chandra catalog. We find good agreement with the photometry of the previously published CDF-S catalogs; however, we provide significantly improved positional accuracy.
Little string amplitudes (and the unreasonable effectiveness of 6D SYM)

We study tree level scattering amplitudes of four massless states in the double scaled little string theory, and compare them to perturbative loop amplitudes in six-dimensional super-Yang-Mills theory. The little string amplitudes are computed from correlators in the cigar coset CFT and in $$ \mathcal{N} $$ = 2 minimal models. The results are expressed in terms of integrals of conformal blocks and evaluated numerically in the α ′ expansion. We find striking agreements with up to 2-loop scattering amplitudes of massless gluons in 6D SU(k) SYM at a ℤ k invariant point on the Coulomb branch. We comment on the issue of UV divergence at higher loop orders in the gauge theory and discuss the implication of our results.
QLISP: a language for the interactive development of complex systems

This paper presents a functional overview of the features and capabilities of QLISP, one of the newest of the current generation of very high level languages developed for use in Artificial Intelligence (AI) research.QLISP is both a programming language and an interactive programming environment. It embeds an extended version of QA4, an earlier AI language, in INTERLISP, a widely available version of LISP with a variety of sophisticated programming aids.The language features provided by QLISP include a variety of useful data types, an associative data base for the storage and retrieval of expressions, the ability to associate property lists with arbitrary expressions, a powerful pattern matcher based on a unification algorithm, pattern-directed function invocation, "teams" of pattern invoked functions, a sophisticated mechanism for breaking a data base into contexts, generators for associative data retrieval, and easy extensibility.System features available in QLISP include a very smooth interaction with the underlying INTERLISP language, a facility for aggregating multiple pattern matches, and features for interactive control of programs.A number of applications to which QLISP has been put are briefly discussed, and some directions for future development are presented.
Bluff Recession Rates Along the Lake Michigan Shoreline in Illinois

Using historical airphotos and maps, we measured amounts of bluff-top retreat at 300 locations along 30 km of the Lake Michigan shoreline from Wilmette to Waukegan, Illinois. For two time periods, 1872–1937 and 1937–1987, rates of retreat vary from 10 to 75 cm/yr between discrete segments of bluffs (defined by lithology) and between time periods for a given bluff segment. The average retreat rates for the entire area, however, do not vary significantly between the two time periods and are approximately 20–25 cm/yr. Long-term average and short-term extreme lake levels and precipitation also do not vary significantly between the two periods, and thus local temporal variations in retreat rate cannot be attributed to these factors. Shore protection built to date may have altered the spatial distribution of retreat rates in the area but has had little overall effect on the average regional retreat rates. Local rate variations correlate closely with lithologic variations of the glacial materials exposed in the bluff, which consist of clay tills and outwash silts, sands, and gravels. The temporally constant regional retreat rates and the regular shape of the local shoreline indicate that a long-term uniform rate of retreat prevails and that local variations in rates balance out through time to produce long-term parallel (in map view) bluff retreat in the area. This parallel retreat probably is controlled by the uniform retreat rate of the lithologically homogeneous shoreface in front of the bluff.
The cellular basis of behavior in Aplysia

Abstract This essay includes some of the more important findings of our continuing research on the nervous system of the sea hare, Aplysia . My associates and I have tried and are trying to understand the temporal organization of behavior in terms of cellular processes and macromolecular metabolism which can be readily studied in the large and identifiable neurons of Aplysia . The long-term cyclic processes which we have discovered in some of these neurons may underlie behaviors such as sleep and waking, reproductive cycles, and periodic feeding. In view of the conservative nature of neuronal physiology, as reviewed earlier, it would be surprising if our investigations of these processes in Aplysia did not have relevance for the vertebrates including man.
A random walk through the field of speckle

The salient features of "classical" speckle patterns are reviewed. The relaxation of assumptions leading to the classical model yields statistical properties that differ from those associated with conventional speckle. Attention is turned to a summary of those new statistical aspects of speckle that have been discovered or explored since the Applications of Speckle Phenomena conference held in August 1980 (Proc. SPIE Vol. 243).
Groups where free subgroups are abundant

Given an infinite topological group G and a cardinal κ>0, we say that G is almost κ-free if the set of κ-tuples (gi)i∈κ∈Gκ which freely generate free subgroups of G is dense in Gκ. In this note we examine groups having this property and construct examples. For instance, we show that if G is a non-discrete Hausdorff topological group that contains a dense free subgroup of rank κ>0, then G is almost κ-free. A consequence of this is that for any infinite set Ω, the group of all permutations of Ω is almost 2|Ω|-free. We also show that an infinite topological group is almost ℵ0-free if and only if it is almost n-free for each positive integer n. This generalizes the work of Dixon, and Gartside and Knight.
SE' Addition of homochiral α-alkoxyallylstannanes to aldehydes

Abstract Addition of the homochiral ( S )-[1-(benzyloxy)methoxy-2-( E )-hexenyl] (tri- n -butyl) stannane (5b) to heptanal (1a), ( E )-2-heptenal (1b), and 2-heptynal (1c) under BF 3 catalysis was examined. In all cases the addition proceeded by anti S E , attack to give mainly the syn E adducts se8a-c with high ee.
Limiting “Sugary Drinks” to Reduce Obesity — Who Decides?

A judge has struck down the New York City Board of Health partial ban on selling sugary drinks in containers larger than 16 ounces. Agencies that overstep their bounds invite backlash, the author writes, making meaningful public health regulation impossible.
Aspirating Probe Measurements of the Unsteady Total Temperature Field Downstream of an Embedded Stator in a Multistage Axial Flow Compressor

The results from the area traverse measurements of the unsteady total temperature using a high-response aspirating probe downstream of the second stator ofa three-stage axial flow compressor are presented. The measurements were conducted at the peak efficiency operating point. The unsteady total temperature data are resolved into deterministic and unresolved components. Hub and casing regions have high levels of unsteadiness and consequently high levels of mixing. These regions have significant levels of shaft resolved and unresolved unsteadiness. Comparisons are made between the total temperature and the total pressure data to examine the rotor 2 wake characteristics and the temporal variation of the stator exit flow
A Programming Language

The paper describes a succinct problem-oriented programming language. The language is broad in scope, having been developed for, and applied effectively in, such diverse areas as microprogramming, switching theory, operations research, information retrieval, sorting theory, structure of compilers, search procedures, and language translation. The language permits a high degree of useful formalism. It relies heavily on a systematic extension of a small set of basic operations to vectors, matrices, and trees, and on a family of flexible selection operations controlled by logical vectors. Illustrations are drawn from a variety of applications.
A modern circadian clock in the common angiosperm ancestor of monocots and eudicots

The circadian clock enhances fitness through temporal organization of plant gene expression, metabolism and physiology. Two recent studies, one in BMC Evolutionary Biology, demonstrate through phylogenetic analysis of the CCA1/LHY and TOC1/PRR gene families that the common ancestor of monocots and eudicots had components sufficient to construct a circadian clock consisting of multiple interlocked feedback loops.
Properties of the Molecular Clouds in NGC 205

The nearby dwarf elliptical galaxy NGC 205 offers a unique opportunity for high-resolution studies of the interstellar medium in an elliptical galaxy. The present paper investigates the distribution of molecular gas, molecular line ratios, and the relationships between atomic gas, molecular gas, and dust in this galaxy. The line ratios 12CO (2–1)/(1–0) and 12CO (1–0)/13CO (1–0) in one of the molecular clouds in NGC 205 are consistent with the ratios found in other elliptical galaxies and in Galactic giant molecular clouds; they suggest that the CO in this cloud is probably subthermally excited. Atomic gas, molecular gas, and dust are very closely associated on scales of ~100 pc; the atomic gas can be understood as a photodissociated envelope around the molecular clouds. The atomic column densities in this galaxy are quite low (≈1020 cm-2) because the interstellar UV field is relatively low. The total gas-to-dust column density ratios are consistent with Galactic gas-to-dust ratios. In short, the molecular gas in NGC 205 seems to have properties very similar to the familiar molecular clouds in our own Galaxy except for the low atomic column densities.
Human Head Dynamic Response to Side Impact by Finite Element Modeling

The dynamic response of the human head to side impact was studied by 2-dimensional finite element modeling. Three models were formulated in this study. Model I is an axisymmetric model. It simulated closed shell impact of the human head, and consisted of a single-layered spherical shell filled wiht an inviscid fluid. The other two models (Model II and III) are plane strain models of a coronal section of the human head. Model II approximated a 50th percentile male head by an outer layer to simulate cranial bone and an inviscid interior core to simulate the intracranial contents. The configuration of Model III is the same as Model II but more detailed anatomical features of the head interior were added, such as, cerebral spinal fluid (CSF); falx cerebri, dura, and tentorium. Linear elastic material properties were assigned to all three models. All three models were loaded by a triangular pulse with a peak pressure of 40 kPa, effectively producing a peak force of 1954 N (440 lb). The purpose of this study was to determine the effects of the membranes and that of the mechanical properties of the skull, brain, and membrane on the dynamic response of the brain during side impact, and to compare the pressure distributions from the plane strain model with the axisymmetric model. A parametric study was conducted on Model II to characterize fully its response to impact under various conditions.(ABSTRACT TRUNCATED AT 250 WORDS)