cssi/SciSciGPT-SciSciNet huggingface dataset:
The effects of bending and stretching vibration on the reaction of acetylene cations with methane

Multiphoton ionization (MPI) has been used to create C2H+2 in selected vibrational states, with excitation in either ν2 (C–C stretch) or a bending vibration (ν5‐cis bend). Reactions of the state selected ions with CH4 and CD4 have been studied in a guided beam mass spectrometer. Absolute cross sections for formation of C3H+n (n=3,4,5) and C2H+3 products are reported for collision energies ranging from 60 meV to 5 eV. Evidence for both complex formation and direct reaction mechanisms is found. Vibrational excitation has different effects on the various product cross sections in different collision energy regimes. Bending excitation has also been found to cause somewhat different effects than C–C stretching vibration.
Wavelet image coding using rate-distortion optimized backward adaptive classification

We introduce a new image compression framework that combines compression efficiency with speed, and is based on an independent infinite mixture model which accurately captures the space-frequency characterization of the wavelet image representation. Specifically, we model individual image wavelet coefficients as being drawn from an independent generalized Gaussian distribution (GGD) field of zero mean and unknown spatially-varying variances. Based on this model, we develop a powerful estimation-quantization (EQ) framework that consists of: (i) first finding the maximum- likelihood estimate of the individual spatially-varying coefficient field variances based on causal and quantized spatial neighborhood contexts; and (ii) then applying an off-line rate-distortion (R-D) optimized quantization/entropy coding strategy, implemented as a fast lookup table, that is optimally matched to the derived variance estimates. A distinctive feature of our framework is the dynamic partitioning of wavelet data into subsets representing coefficients that are 'predictable' and 'unpredictable' respectively from their quantized causal contexts. The statistical parameters of the 'unpredictable' set in each subband, obtained through a fast, R-D based, simple thresholding first-pass operation, represent the negligible parametric side-information for use in the forward adaptation mode. The combination of the powerful infinite mixture model, the dynamic switching between forward and backward adaptation modes, and the theoretical soundness and speed of the EQ framework lead to a novel, high-performing, and fast image coder that is extremely competitive with the best published coders in the literature across all classes of images and target bit rates of interest, in both compression efficiency and processing speed. For example, our coder exceeds the objective performance of the best zerotree-based wavelet coder at all bit rates for all tested images at a fraction of its complexity. At mow to medium bit rates our preliminary results appear to exceed all reported results in the wavelet image coding literature to the best of our knowledge.© (1997) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Citing for high impact

The question of citation behavior has always intrigued scientists from various disciplines. While general citation patterns have been widely studied in the literature we develop the notion of citation projection graphs by investigating the citations among the publications that a given paper cites. We investigate how patterns of citations vary between various scientific disciplines and how such patterns reflect the scientific impact of the paper. We find that idiosyncratic citation patterns are characteristic for low impact papers; while narrow, discipline-focused citation patterns are common for medium impact papers. Our results show that crossing-community, or bridging citation patters are high risk and high reward since such patterns are characteristic for both low and high impact papers. Last, we observe that recently citation networks are trending toward more bridging and interdisciplinary forms.
Simulating Photons and Plasmons in a Three-dimensional Lattice

Three-dimensional metallic photonic structures are studied using a newly developed mixed finite element-finite difference (FE-FD) code, Curly3d. The code solves the vector Helmholtz equation as an eigenvalue problem in the unit cell of a triply periodic lattice composed of conductors and/or dielectrics. The mixed FE-FD discretization scheme ensures rapid numerical convergence of the eigenvalue and allows the code to run at low resolution. Plasmon and photonic band structure calculations are presented.
Parallel clustering algorithms for structured AMR

We compare several different parallel implementation approaches for the clustering operations performed during adaptive meshing operations in patch-based structured adaptive mesh refinement (SAMR) applications. Specifically, we target the clustering algorithm of Berger and Rigoutsos, which is commonly used in many SAMR applications. The baseline for comparison is a single program, multiple data extension of the original algorithm that works well for up to O(102) processors. Our goal is a clustering algorithm for machines of up to O(105) processors, such as the 64K-processor IBM BlueGene/L (BG/L) system. We first present an algorithm that avoids unneeded communications of the baseline approach, improving the clustering speed by up to an order of magnitude. We then present a new task-parallel implementation to further reduce communication wait time, adding another order of magnitude of improvement. The new algorithms exhibit more favorable scaling behavior for our test problems. Performance is evaluated on a number of large-scale parallel computer systems, including a 16K-processor BG/L system.
A Novel Online Stator Ground-Wall Insulation Monitoring Scheme for Inverter-Fed AC Motors

Insulation failures are one of the most common failure modes of ac motors, particularly high-voltage motors. Online monitoring of insulation health of ac motors is important for preventing unexpected outages and minimizing the associated financial losses, particularly in critical applications. Previously, an online ground-wall insulation monitoring technique has already been proposed for six-lead ac motors. In this paper, a novel online ground-wall insulation monitoring scheme is proposed for inverter-fed ac motors. This approach is based on measurement of common-mode insulation leakage current for online capacitance and dissipation factor (C/DF) monitoring. The proposed technique can be applied to both three-lead and six-lead ac motors and can also be extended to monitor the insulation health of the cable connecting the inverter and the motor. The proposed technique is demonstrated in the lab environment and correlated with standard offline C/DF measurements.
Direct numerical simulations of the Navier-Stokes alpha model

Abstract We explore the utility of the recently proposed alpha equations in providing a subgrid model for fluid turbulence. Our principal results are comparisons of direct numerical simulations of fluid turbulence using several values of the parameter alpha, including the limiting case where the Navier–Stokes equations are recovered. Our studies show that the large scale features, including statistics and structures, are preserved by the alpha models, even at coarser resolutions where the fine scales are not fully resolved. We also describe the differences that appear in simulations. We provide a summary of the principal features of the alpha equations, and offer some explanation of the effectiveness of these equations used as a subgrid model for three-dimensional fluid turbulence.
Synthesis, structural characterization, and properties of the organothorium alkylthiolate complex [(CH3)5C5]2Th(SCH2CH2CH3)2

This contribution reports the synthesis and characterization of the organothorium alkylthiolate complex [(CH 3 ) 5 C 5 ] 2 Th(SCH 2 CH 2 CH 3 ) 2 . This compound crystallizes in the monoclinic space group C 2/ c (#15) with four molecules in a cell of dimensions a =19.066(2), b =11.603(1), c =16.379(2) A, and β =130.08(1)°. Least-squares refinement led to a value for the conventional R index (on F o ) of 0.040 for 132 variables and 2030 observations having F o 2 ⩾3σ( F o 2 ). The molecular structure consists of an unexceptional ‘bent sandwich’ [(CH 3 ) 5 C 5 ] 2 Th fragment coordinated to two n-propylthiolate ligands. The ThS bond distance is 2.718(3) A; the SC(α) distance, 1.78(2) A; the ThSC(α) angle, 108.3(5)°; and the SThS′ angle, 102.5(2)°. Contrasts are drawn with the structures of analogous actinide alkoxides
TRUEX Processing of Plutonium Analytical Solutions at Argonne National Laboratory

Abstract The TRUEX (TRansUranic EXtraction) solvent extraction process was developed at Argonne National Laboratory (ANL) for the Department of Energy. A TRUEX demonstration completed at ANL involved the processing of analytical and experimental waste generated there and at the New Brunswick Laboratory. A 20-stage centrifugal contactor was used to recover plutonium, americium, and uranium from the waste. Approximately 84 g of plutonium, 18 g of uranium, and 0.2 g of americium were recovered from about 118 L of solution during four process runs. Alpha decontamination factors as high as 65,000 were attained, which was especially important because it allowed the disposal of the process raffinate as a lowlevel waste. The recovered plutonium and uranium were converted to oxide; the recovered americium solution was concentrated by evaporation to approximately 100 mL. The flowsheet and operational procedures were modified to overcome process difficulties. These difficulties included the presence of complexants i...
Regulation of Cerebral Autoregulation by Carbon Dioxide

Cerebral autoregulation describes a mechanism that maintains cerebral blood flow stable despite fluctuating perfusion pressure. Multiple nonperfusion pressure processes also regulate cerebral perfusion. These mechanisms are integrated. The effect of the interplay between carbon dioxide and perfusion pressure on cerebral circulation has not been specifically reviewed. On the basis of the published data and speculation on the aspects that are without supportive data, the authors offer a conceptualization delineating the regulation of cerebral autoregulation by carbon dioxide. The authors conclude that hypercapnia causes the plateau to progressively ascend, a rightward shift of the lower limit, and a leftward shift of the upper limit. Conversely, hypocapnia results in the plateau shifting to lower cerebral blood flows, unremarkable change of the lower limit, and unclear change of the upper limit. It is emphasized that a sound understanding of both the limitations and the dynamic and integrated nature of cerebral autoregulation fosters a safer clinical practice.
External finance and firm survival in the aftermath of the crisis : evidence from Eastern Europe and Central Asia

Two data sets are used to study how country and firm characteristics affected firms' financial constraints and their likelihood of survival during the early phase of the recent global financial crisis in Eastern Europe and Central Asia, a region that was especially hard hit. The first data source provides information on the reported severity of financial constraints for 360 firms from 23 countries in 2002, 2005, and 2008. By following the same firms over time, the study summarizes both the gradual easing of financial constraints from 2002 to 2005 and their tightening during the crisis. Key findings are that financial constraints during the crisis were less severe in countries with well-established foreign banks (entered prior to year 2000), and that changes in the severity of financial constraints were more pronounced for large firms than others during the crisis (although large firms continued to have less severe constraints on average). The second data source provides information on whether firms remained in operation in 2009 in six countries in Eastern Europe and Central Asia. Controlling for other relevant characteristics, firms were more likely to survive the crisis if they had access to external credit.
Ligand-Controlled Palladium-Catalyzed Regiodivergent Suzuki–Miyaura Cross-Coupling of Allylboronates and Aryl Halides

An orthogonal set of catalyst systems has been developed for the Suzuki–Miyaura coupling of 3,3-disubstituted and 3-monosubstituted allylboronates with (hetero)aryl halides. These methods allow for the highly selective preparation of either the α- or the γ-isomeric coupling product.
Chemical and physical studies of type 3 chondrites - III. Chondrules from the Dhajala H3.8 chondrite

Thermoluminescence (TL) properties have been measured in 58 chondrules separated from the Dhajala H3.8 chondrite. The pyrolytic chondrules are noted to have higher mass-normalized TL values than nonpyrolytic ones. Significant correlations are noted between log(TL) and the bulk CaO, Al2O3, and MnO content of the chondrules. These, together with correlations of log(TL) with the CaO, Al2O3, SiO2 and normative anorthite content of the chondrule glass, indicate an association of the TL and the abundance and position of mesostasis. It is suggested that the TL level in a given chondrule is governed by its bulk composition and metamorphism, and it is hypothesized that the devitrification resistance of unequilibrated chondrule mesostasis explains the unequilibration of certain chondrules in type 3 ordinary chondrites.
Design of a Compliant Endoscopic Suturing Instrument

This paper describes the initial design and optimization of a compliant endoscopic suturing instrument. The emerging field of Natural Orifice Transluminal Endoscopic Surgery (NOTES) requires innovative instruments to meet the size limitations inherent in this type of minimally invasive surgery; using compliant mechanisms is proposed as one method of meeting this requirement. The compliant design was modeled and optimized to maximize the distal opening and provide a puncture force of at least 4.6 N, while being small enough to fit within a 3.3 mm working channel. The design utilizes contact for stress relief and intertwining parts for added deflection. ANSYS® was used for finite element analysis including contact and nonlinear deformations. A prototype was fabricated from the optimized geometry and experimentally tested. The best geometry is predicted to have a distal opening of 14.6 mm at the tips and supply a puncturing force of 4.83 N. The force supplied at the tip was measured and was found to exceed the required 4.6 N. The prototype successfully passed two complete sutures and qualitative results are provided. The results of the study will lead to further refinements and improvements in future designs.
Effective and Equitable Adoption of Opt-In Residential Dynamic Electricity Pricing

Time-varying retail electricity pricing is very popular with economists, but has little support among regulators and consumers. I propose an opt-in time-varying residential pricing plan that would be equitable to both customers who opt in and those who don’t. Low-income households would, on average, see almost no change in their bills under time-varying pricing, while low-consumption households would see their bills decline somewhat and high-consumption households would see their bills rise. Most importantly, I show that the opt-in approach is unlikely to increase the flat rate charged to other customers by more than a few percentage points.
Simulated Quantum Computation of Global Minima

Finding the optimal solution to a complex optimisation problem is of great importance in practically all fields of science, technology, technical design and econometrics. We demonstrate that a modified Grover's quantum algorithm can be applied to real problems of finding a global minimum using modest numbers of quantum bits. Calculations of the global minimum of simple test functions and Lennard-Jones clusters have been carried out on a quantum computer simulator using a modified Grover's algorithm. The number of function evaluations N reduced from O(N) in classical simulation to O(N 1/2) in quantum simulation. We also show how the Grover's quantum algorithm can be combined with the classical Pivot method for global optimisation to treat larger systems.
Measurement distortion and missing contingencies in optimal contracts

Theory suggests that optimal contracts should include many contingencies to achieve optimal risk sharing. However, in practice, few contracts are as complex as theory suggests. This paper develops a model which is consistent with this observation. The lack of risk sharing results from the interplay of two factors. First, contingencies must be based on information produced by measurement systems, which may be manipulable. Second, when two parties to a contract meet, they often have incomplete information. The type of contract offered may reveal information about the party who proposes it. Different types of agents have different preferences over contingent contracts, because they have different abilities to manipulate the measurement system. These differences in preferences allow the parties to signal their types through the contracts they offer. Noncontingent contracts may be chosen in equilibrium because they are the only contracts which do not give any type an incentive to distort the measurement system and, hence, do not reveal information about the party proposing the contract.
Long-period x-ray standing waves generated by total external reflection

X-ray standing waves generated above a mirror surface during total external reflection have been used to locate a heavy atom layer which was embedded hundreds of angstroms above the mirror surface in a Langmuir-Blodgett multilayer. This same method has also been used to map out the ion distribution in the diffuse double layer that forms at the electrolyte/charged surface interface.© (1991) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Time-course of extracellular nicotine and cotinine levels in rat brain following administration of nicotine: effects of route and ethanol coadministration

Rationale Nicotine and ethanol are commonly coabused drugs, and nicotine-laced ethanol products are growing in popularity. However, little is known about time-course changes in extracellular nicotine and cotinine levels in rat models of ethanol and nicotine coabuse.
Branes, superpotentials and superconformal fixed points

Abstract We analyze various brane configurations corresponding to field theories in three, four and five dimensions. We find brane configurations which correspond to three-dimensional N = 2 and four-dimensional N = 1 supersymmetric QCD theories with quartic superpotentials, in which what appear to be “hidden parameters” play an important role. We discuss the construction of five-dimensional N = 1 supersymmetric gauge theories and superconformal fixed points using branes, which leads to new five-dimensional N = 1 superconformal field theories. The same five-dimensional theories are also used, in a surprising way, to describe new superconformal fixed points of three-dimensional N = 2 supersymmetric theories, which have both “electric” and “magnetic” Coulomb branches.
On Free Stochastic Differential Equations

The paper derives an equation for the Cauchy transform of the solution of a free stochastic differential equation (SDE). This new equation is used to solve several particular examples of free SDEs.
Okounkov bodies and restricted volumes along very general curves

Abstract Given a big divisor D on a normal complex projective variety X, we show that the restricted volume of D along a very general complete-intersection curve C ⊂ X can be read off from the Okounkov body of D with respect to an admissible flag containing C. From this we deduce that if two big divisors D 1 and D 2 on X have the same Okounkov body with respect to every admissible flag, then D 1 and D 2 are numerically equivalent.
Open source: the Russian experience legislation and practice

The emergence of so-called free or open-source software and the growth of its economic importance in various industries make questions regarding the legal status of free/open-source licenses especially important. In December 2010, new draft amendments to the Civil Code were published, introducing new concepts in order to reflect the ideas pursued by these types of licenses. This article analyzes existing problems with the legal status of free/open-source licenses, whether proposed amendments may solve them, and what risks they may create. Since Russia is among the first countries trying to include provisions on free/open-source licenses in its legislation, such analysis may be of interest to foreign lawmakers since the concept of open source is universal all over the world.
One- and two-armed lariat ether peptide derivatives: syntheses and cation binding properties

Abstract Series of peptide-based lariat ethers derived from aza-18-crown-6 and bibracchial lariat ethers (BiBLEs) based on 4,13-diaza-18-crown-6 have been prepared. Sidearms incorporate inter alia the amino acids glycine, alanine, phenylalanine, leucine, isoleucine, and valine. Cation binding affinities for Na + and K + are reported.
Is There a Retirement-Consumption Puzzle? Evidence Using Subjective Retirement Expectations

Abstract Previous research finds a systematic decrease in consumption at retirement, a finding that is inconsistent with the life cycle/permanent income hypothesis if retirement is an expected event. In this paper, we use workers' subjective beliefs about their retirement dates as an instrument for retirement. After demonstrating that subjective retirement expectations are strong predictors of subsequent retirement decisions, we still find a consumption decline at retirement for workers who retire when expected. However, our estimates of this consumption fall are about a third less than those found when we instead rely on the instrumental variables strategy used in prior studies.
An analysis of the Hubble Space Telescope fine guidance sensor Fine Lock mode

There are two guiding modes of the Hubble Space Telescope used for the acquisition of astronomical data by one of its six scientific instruments. The more precise one is called Fine Lock. Command and control problems in the on-board electronics, compounded by the aberrations in the main optics, has limited routinely successful Fine Lock to brighter stars, V less than 13.0 mag, instead of fulfilling its prelaunch goal of V = 14.5 mag. Consequently, the less precise guiding mode of Coarse Track (about 25 milliarcsecond in practice) has to be used fairly frequently. Indeed, almost half of the celestial hemisphere has stars too faint to support guidance in the Fine Lock mode. Hence, some of the scientific observations to have been made with the Hubble Space Telescope will be compromised. In this paper a report on the only realistic or extensive simulations of the Fine Lock guidance mode is presented. The theoretical analysis underlying the Monte Carlo experiments and the numerical computations show that the control electronics have significant limitations and how to adjust the various control parameters in an attempt to extend Fine Lock guiding performance back to V - 14.0 mag.
Exactly how has income inequality changed? : Patterns of distributional change in core societies

The recent resurgence of income inequality in some of the core societies has spawned a wide-ranging debate as to the culprits. Progress in this debate has been complicated by the fact that many of ...
Stereochemical course of reductive deamination induced by difluoroamine

Abstract Optically active 2-phenyl-2-butylamine reacts with HNF 2 to give 2-phenylbutane with 56% net retention of configuation.
An FPGA-based In-Line Accelerator for Memcached

We present a method for accelerating server applications using a hybrid CPU+FPGA architecture and demonstrate its advantages by accelerating Memcached, a distributed key-value system. The accelerator, implemented on the FPGA fabric, processes request packets directly from the network, avoiding the CPU in most cases. The accelerator is created by profiling the application to determine the most commonly executed trace of basic blocks which are then extracted. Traces are executed speculatively within the FPGA. If the control flow exits the trace prematurely, the side effects of the computation are rolled back and the request packet is passed to the CPU. When compared to the best reported software numbers, the Memcached accelerator is 9.15× more energy efficient for common case requests.
Photoinduced, copper-catalyzed alkylation of amides with unactivated secondary alkyl halides at room temperature.

The development of a mild and general method for the alkylation of amides with relatively unreactive alkyl halides (i.e., poor substrates for SN2 reactions) is an ongoing challenge in organic synthesis. We describe herein a versatile transition-metal-catalyzed approach: in particular, a photoinduced, copper-catalyzed monoalkylation of primary amides. A broad array of alkyl and aryl amides (as well as a lactam and a 2-oxazolidinone) couple with unactivated secondary (and hindered primary) alkyl bromides and iodides using a single set of comparatively simple and mild conditions: inexpensive CuI as the catalyst, no separate added ligand, and C–N bond formation at room temperature. The method is compatible with a variety of functional groups, such as an olefin, a carbamate, a thiophene, and a pyridine, and it has been applied to the synthesis of an opioid receptor antagonist. A range of mechanistic observations, including reactivity and stereochemical studies, are consistent with a coupling pathway that inclu...
Waveform selection based on detection-tracking performance

In this paper, radar/sonar waveform selection is investigated form a system engineering viewpoint using the hybrid conditional averaging (HYCA) method. HYCA is a recently developed technique for evaluating tracking performance, and is meeting with increased acceptance due to this ability to work with the dynamic interaction between tracking and imperfect detection. In a previous paper HYCA was used as an analysis tool to select among various apportionments of constant-frequency and linear frequency- sweep waveforms, and the effect of missed detections was incorporated; the tracking mechanism was taken as a Kalman filter. In this paper our analysis is refined to deal both with false alarms and an improved detection model. With respect to the former, the Kalman estimator has been replaced by a probabilistic data association filter, in which Poisson-distributed false-alarms may be included in a natural way. With respect to the latter, the resolution cells have been redefined according to a tessellating grid in range and range-rate, with the effect of detections in neighboring cells caused by ambiguity-function 'sidelobes' and over/undersampling accounted for.© (1998) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Nucleophilic substitution gone awry: A novel cyclopropanation reaction with a surprising stereochemical outcome

Lithium triethylborohydride reacts with the triisopropylbenzene sulfonate ester of 2-methoxy-5,5-dimethyl-2-vinyl-3-cyclohexen-1-ol (1) to afford 8-methoxy-6,6-dimethylspiro[2.5]oct-4-ene (3). Labeling studies reveal that this novel cyclopropane forming reaction proceeds with retention of configuration at the newly formed quaternary center.
Remarkable examples of double diastereodifferentiation: Application to the Eudistomin and Eudistomidin alkaloids

Abstract Nucleophilic addition of chiral enolates 1 and ent- 1 with chiral iminium ion 2a occur with total stereochemical control.
Oil prices and rural migration: the Dutch disease goes south

Abstract We construct a two-period general equilibrium model to evaluate policies affecting agricultural migration and exports. The model is applied to Mexico for the period 1986–1987 to obtain certain qualitative policy conclusions related to the ‘Dutch disease’ brought about by oil price increases. Dutch disease phenomena can be brought about both as the result of real exchange rate changes as well as price changes caused by migration out of agriculture. In the short run it may be possible to use fiscal policy, such as value-added subsidies to agriculture, to at least partially negate the effects of an oil price increase on agricultural exports. (JEL F31, F41).
Analysis of error processes in computer software

A non-homogeneous Poisson process is used to model the occurrence of errors detected during functional testing of command and control software. The parameters of the detection process are estimated by using a combination of maximum likelihood and weighted least squares methods. Once parameter estimates are obtained, forecasts can be made of cumulative number of detected errors. Forecasting equations of cumulative corrected errors, errors detected but not corrected, and the time required to detect or correct a specified number of errors, are derived from the detected error function. The various forecasts provide decision aids for managing software testing activities. Naval Tactical Data System software error data are used to evaluate several variations of the forecasting methodology and to test the accuracy of the forecasting equations. Because of changes which take place in the actual detected error process, it was found that recent error observations are more representative of future error occurrences than are early observations. Based on a limited test of the model, acceptable accuracy was obtained when using the preferred forecasting method.
Rotations and cessations of the large-scale circulation in turbulent Rayleigh–Bénard convection

We present a broad range of measurements of the angular orientation θ0(t )o f the large-scale circulation (LSC) of turbulent Rayleigh-B´ enard convection as a function of time. We used two cylindrical samples of different overall sizes, but each with its diameter nearly equal to its height. The fluid was water with a Prandtl number of 4.38. The time series θ0(t) consisted of meanderings similar to a diffusive process, but in addition contained large and irregular spontaneous reorientation events through angles �θ . We found that reorientations can occur by two distinct mechanisms. One consists of a rotation of the circulation plane without any major reduction of the circulation strength. The other involves a cessation of the circulation, followed by a restart in a randomly chosen new direction. Rotations occurred an order of magnitude more frequently than cessations. Rotations occurred with a monotonically decreasing probability distribution p(�θ ), i.e. there was no dominant value of �θ and small �θ were more common than large ones. For cessations, p(�θ ) was uniform, suggesting that information of θ0(t) is lost during cessations. Both rotations and cessations have Poissonian statistics in time, and can occur at any θ0. The average azimuthal rotation rate | ˙ θ| increased as the circulation strength of the LSC decreased. Tilting the sample relative to gravity significantly reduced the frequency of occurrence of both rotations and cessations.
Failure of Capillary Theory of Frost Damage as Applied to Ceramics

The behavior of solid bars of porous ceramics saturated with water was investigated during the freezing and melting of the water. The length change, differential temperature, and temperature were monitored continuously during the experiments. The behavior of the saturated bars during the freezing of water was analyzed in detail. It was shown that quasi-equilibrium conditions, as assumed by the capillary theory of frost damage, did not satisfactorily describe the results of these experiments because the plasticity of the ice phase is too low to permit pressure equilibration.
The preparation of HCF2CdX and HCF2ZnX via direct insertion into the carbon halogen bond of CF2HY (Y = Br, I)

Abstract The difluoromethylcadmium and zinc reagents have been prepared in DMF via direct insertion of Cd0 into the carbon halogen bond of CF2HY (Y = Br, I). These reagents are stable at 65–75 °C and exhibit prolonged stability and activity at room temperature. Metathesis of the difluoromethylcadmium reagents with Cu(I)X (X = Br, Cl) at −55 °C rapidly produces difluoromethylcopper. The copper reagent is significantly less stable than the cadmium or zinc reagent and rapidly decomposes at room temperature. The difluoromethylcadmium and copper reagents exhibit good reactivity with allylic halides, propargylic derivatives and 1-iodoalkynes to provide good yields of the corresponding difluoromethylalkenes, difluoromethylallenes and difluoromethyl-2-alkynes. Alkylation is successful only with reactive alkyl halides. Generally, the difluoromethylcopper reagent is more reactive than the difluoromethylcadmium reagent and generally exhibits higher regioselectivity in reactions that can occur by either α- or γ-attack.
Stock Options, R&D, and the R&D Tax Credit

Two separate streams of research find evidence that firms decrease R&D spending to meet earnings benchmarks and that the R&D tax credit increases R&D spending. However, these studies do not consider stock option exercises by R&D employees that likely influence R&D spending decisions because they increase R&D tax credits without reducing reported earnings. This study extends both areas of research by incorporating R&D tax credits from stock option exercises into the R&D spending decision. We find evidence that firms reduce R&D spending by 0.46 percent of total assets to avoid earnings decreases, but R&D tax credits generated by stock option exercises offset this decrease by 16 percent on average and up to 42 percent for a fully taxable firm. The results of this study suggest that the tax benefits of R&D‐related stock option exercises are important considerations in studies that investigate myopic R&D investment and in studies that investigate the effect of the R&D tax credit on R&D spending.
Measuring the Cosmic Equation of State with Counts of Galaxies. II. Error Budget for the DEEP2 Redshift Survey

In a previous paper, we described a new variant on the classical "dN/dz" test that could be performed using data from the next generation of redshift surveys. By studying the apparent abundance of galaxies as a function of their circular velocity or velocity dispersion rather than luminosity, it is possible to avoid many of the uncertainties of galaxy evolution while using quantities that may be measured directly. In that work, we assumed that counting statistics would dominate the resulting errors. Here we present the results of including cosmic variance and determine the impact of systematic effects on attempts to perform the test with the upcoming DEEP2 Redshift Survey. For the DEEP2 survey geometry, cosmic variance yields errors roughly twice those predicted from Poisson statistics. Through Monte Carlo simulations we find that if the functional form, but not the strength, of any of the major systematic effects (baryonic infall, velocity errors, and incompleteness) is known, the free parameter may be determined from the observed velocity function. The systematic may then be corrected for, leaving a much smaller residual error. The total uncertainty from systematics is comparable to that from cosmic variance but is correlated among redshift bins. Based on these analyses, we present error budgets for a dN/dz measurement with DEEP2 and determine the resulting constraints on cosmological parameters. We find that the uncertainty in the cosmic equation of state parameter w are ~2 times higher than previously derived, providing a measurement much stronger than any available today but weaker than some other proposed tests.
Rhodium-catalyzed redox allylation reactions of ketones

Ketones react with allyl acetate to generate tertiary homoallylic alcohols in the presence of a rhodium catalyst and bis(pinacolato)diboron. A range of substrates, including aryl, alkyl and cyclic ketones react smoothly under these conditions. Diastereoselective allylation reactions of functionalized ketones such as pregnenolone acetate are also reported.
A Post-Processing Receiver for the Lunar Laser Communications Demonstration Project

The Lunar Laser Communications Demonstration Project undertaken by MIT Lincoln Laboratory and NASA’s Goddard Space Flight Center will demonstrate high-rate laser communications from lunar orbit to the Earth. NASA’s Jet Propulsion Laboratory is developing a backup ground station supporting a data rate of 39 Mbps that is based on a non-real-time software post-processing receiver architecture. This approach entails processing sample-rate-limited data without feedback in the presence high uncertainty in downlink clock characteristics under low signal flux conditions. In this paper we present a receiver concept that addresses these challenges with descriptions of the photodetector assembly, sample acquisition and recording platform, and signal processing approach. End-to-end coded simulation and laboratory data analysis results are presented that validate the receiver conceptual design.
Consumer Inertia and Firm Pricing in the Medicare Part D Prescription Drug Insurance Exchange

I use the Medicare Part D prescription drug insurance market to examine the dynamics of firm interaction with consumers on an insurance exchange. Enrollment data show that consumers face switching frictions leading to inertia in plan choice, and a regression discontinuity design indicates initial defaults have persistent effects. In the absence of commitment to future prices, theory predicts firms respond to inertia by raising prices on existing enrollees, while introducing cheaper alternative plans. The complete set of enrollment and price data from 2006 through 2010 confirms this prediction: older plans have approximately 10 percent higher premiums than comparable new plans. (JEL G22, I13, I18, L11, L65)
High quality actively cooled plasma facing components for fusion

Abstract This paper interweaves some suggestions for developing actively cooled plasma-facing components (PFCs) for future fusion devices, with supporting examples taken from the design, fabrication and operation of Tore Supra's Phase III outboard pump limiter (OPL). This actively cooled midplane limiter, designed for heat and particle removal during long-pulse operation, has been operated under essentially thermally steady state conditions. Testing to identify braze flaws, analysis of the impact of joining flaws on the thermal-hydraulic performance of the OPL, and the extensive calorimetry and IR thermography used to confirm and update safe operating limits for power handling of the OPL are reviewed. This experience suggests that, for PFCs in future fusion devices, flaw-tolerant designs are possible; analyses of the impacts of flaws on performance can provide criteria for quality assurance; and validating appropriate methods of inspection for such flaws early in the design development of PFCs is prudent. The need for in-service monitoring is also discussed.
Phonon densities of states and related thermodynamic properties of high temperature ceramics.

Abstract Structural components and semiconductor devices based on silicon nitride, aluminum nitride and gallium nitride are expected to function more reliably at elevated temperatures and at higher levels of performance because of the strong atomic bonding in these materials. The degree of covalency, lattice specific heat, and thermal conductivity are important design factors for the realization of advanced applications. We have determined the phonon densities of states of these ceramics by the method of neutron scattering. The results provide a microscopic interpretation of the mechanical and thermal properties. Moreover, experimental data of the static structures and dynamic excitations of atoms are essential to the validation of interparticle potentials employed for molecular-dynamics simulations of high-temperature properties of multi-component ceramic systems. We present an overview of neutron-scattering investigations of the atomic organization, phonon excitations, as well as calculations of related thermodynamic properties of Si 3 N 4 , β -sialon, AlN and GaN. The results are compared with those of the oxide analogs such as SiO 2 and Al 2 O 3 .
Bayesian robust inference of sample selection using selection-t models

Heckman selection model is the most popular econometric model in analysis of data with sample selection. However, selection models with Normal errors cannot accommodate heavy tails in the error distribution. Recently, Marchenko and Genton proposed a selection-t model to perform frequentist' robust analysis of sample selection. Instead of using their maximum likelihood estimates, our paper develops new Bayesian procedures for the selection-t models with either continuous or binary outcomes. By exploiting the Normal mixture representation of the t distribution, we can use data augmentation to impute the missing data, and use parameter expansion to sample the restricted covariance matrices. The Bayesian procedures only involve simple steps, without calculating analytical or numerical derivatives of the complicated log likelihood functions. Simulation studies show the vulnerability of the selection models with Normal errors, as well as the robustness of the selection models with t errors. Interestingly, we find evidence of heavy-tailedness in three real examples analyzed by previous studies, and the conclusions about the existence of selection effect are very sensitive to the distributional assumptions of the error terms.
Application of intramolecular Heck reactions to the preparation of steroid and terpene intermediates having cis A-B ring fusions. Model studies for the total synthesis of complex cardenolides.

The cis-fused tricyclic dienone 13 is the major product formed from intramolecular Heck cyclization of the dienyl triflate 12 (Scheme I). Similarly, the cis-hexahydrophenanthridine 22 is formed in good yield from Heck cyclization of the aryl triflate 21. This latter conversion demonstrates that allylic ether substitution is compatible with intramolecular Heck chemistry and suggests applications of this chemistry in the synthesis of highly oxidized cardenolides.
CHANDRA IMAGING AND SPECTROSCOPY OF THE EASTERN XA REGION OF THE CYGNUS LOOP SUPERNOVA REMNANT

The XA region of the Cygnus Loop is a bright knot of X-ray emission on the eastern edge of the supernova remnant. The emission results from the interaction of the supernova blast wave with density enhancements at the edge of a precursor formed cavity. However, this interaction is complex given the irregular morphology of the cavity wall. To study the nature and origin of the X-ray emission, we use high spatial resolution images from Chandra. We extract spectra from these images to analyze the physical conditions of the plasma. Our goal is to probe the density of various regions to form a picture of the cavity wall and characterize the interaction between this supernova and the local interstellar medium. We find that a series of regions along the edge of the X-ray emission appears to trace out the location of the cavity wall. The best-fit plasma models result in two temperature component equilibrium models for each region. The low-temperature components have densities that are an order of magnitude higher than the high-temperature components. The high-density plasma may exist in the cavity wall where it equilibrates rapidly and cools efficiently. The low-density plasma is interior to the enhancement and heated furthermore » by a reverse shock from the wall. Calculations of shock velocities and timescales since shock heating are consistent with this interpretation. Furthermore, we find a bright knot of emission indicative of a discrete interaction of the blast wave with a high-density cloud in the cavity wall with a size scale {approx}0.1 pc. Aside from this, other extractions made interior to the X-ray edge are confused by line-of-sight projection of various components. Some of these regions show evidence of detecting the cavity wall but their location makes the interpretation difficult. In general, the softer plasmas are well fit at temperatures (kT){approx} 0.11 keV, with harder plasmas at temperatures of (kT){approx} 0.27 keV. All regions displayed consistent metal depletions most notably in N, O, and Ne at an average of 0.54, 0.55, and 0.36 times solar, respectively.« less
Handling Qualities Evaluation of Pilot Tools for Spacecraft Docking in Earth Orbit

A new generation of spacecraft is now under development by NASA to replace the Space Shuttle and return astronauts to the Moon. These spacecraft will have a manual control capability for several mission tasks, and the ease and precision with which pilots can execute these tasks will have an important effect on mission risk and training costs. This paper focuses on the handling qualities of a spacecraft based on dynamics similar to that of the Crew Exploration Vehicle, during the last segment of the docking task with a space station in low Earth orbit. A previous study established that handling qualities for this task degrade significantly as the level of translation-into-rotation coupling increases. The goal of this study is to evaluate the efficacy of various pilot aids designed to mitigate the handling qualities degradation caused by this coupling. Four pilot tools were ev adluaetead:d-band box/indicator, flight-path marker, translation guidance cues, and feed-forward control. Each of these pilot tools improved handling qualities, generally with greater improvements resulting from using these tools in combination. A key result of this study is that feedforward control effectively counteracts coupling effects, providing solid Level 1 handling qualities for the spacecraft configuration evaluated.
The head pattern in Amblystoma studied by vital staining and transplantation methods

Local vital stains were applied to the prospective head region in the late yolk plug stage of Amblystoma punctatum by Vogt's1 method. From the records obtained by making camera lucida drawings of the position and extent of the stained areas in the stages following, composite diagrams were constructed showing the arrangement of the parts of the prospective ectoderm involved in the formation of the nose, lens, ear, balancer, gills and stomodaeum. Two of these, Harrison stages 13 (slit blastopore) and 22 (shortly after closure of neural folds), are shown in the figures.The wheeling about of the head epidermis due to the dorsal convergence of the neural material which lies almost out at the equator of the embryo in the gastrula stage, takes place in Amblystoma punctatum in a manner similar to that observed by Vogt2 and Goerttler3 on European salamanders. There is a forward and downward growth of the ectoderm of the head region anteriorly in such a way that the material at the middle of the transverse fold com...
Combining Interactive Exploration and Optimization for Assembly Design

This paper presents an integrated framework for conceptual assembly design. Because the complexity of assembly design leads to extremely large design spaces, adequate support of design space exploration is a key issue that must be addressed. CAMF allows the designer to manage the overall design process and explore the design space through explicit representation of design stages and their relationships (history), assembly design constraints, and rationale. The designer is free to use both bottom-up or top-down approaches to explore different assembly configurations. Exploration of the design space is further enabled by incorporating a simulated annealing-based refinement tool that allows the designer to rapidly complete partial designs, refine complete designs, and generate multiple design alternatives.
The border effect in the Japanese market: A Gravity Model analysis

Abstract This paper uses a Gravity Model to analyze the border effect in the Japanese market, which indicates how biased interregional trade is compared with international trade. The results suggest that the border effect in Japan is much lower than in the United States and Canada, and has declined year by year between 1960 and 1990. Possible reasons for the decline include the reduction of tariff rates and non-tariff barriers, the surge of foreign direct investment, and the appreciation of the yen. J. Japanese Int. Economies 18 (1) (2004) 1–11.