cssi/SciSciGPT-SciSciNet huggingface dataset:
Free radical propulsion concept

ANEW propulsion concept which may have particular usefulness for transfer of loads from low Earth orbit (LEO) to geosynchronou s Earth orbit (GEO) is presented. Electrical energy in the form of microwaves is used to heat a propellant gas, thus providing thrust. An outline of the concept and experimental results in support of it are presented. Contents A variety of possible future space missions involve the transfer of substantial masses from LEO to GEO. 1 A crucial factor in propulsion systems designed to meet this need is the ratio of total mass required in LEO to payload mass in GEO, due to the fact that Earth-to-orbit cost is a major fraction of total cost. Systems presently considered for such missions include chemical systems and electrostatic ion propulsion systems. Figure 1 presents payload mass ratio as a function of specific impulse for these systems. Chemical systems provide short trip times at the expense of mass ratios of 3 or greater. Electrostatic ion propulsion systems can achieve mass ratios of 1.25-2.5, but require trip times of 50 days or longer. There is an intermediate range of specific impulse not accessible to present systems which would allow moderate trip times while maintaining mass ratios similar to those of electrostatic systems. The free radical propulsion concept presented here may prove capable of operating in that regime. The concept is illustrated schematically in Fig. 2. Electric power from solar panels is used to operate a microwave generator, and microwave energy is coupled to a propellant gas by means of a resonant cavity. The gas is ionized partially by the microwave fields, and inelastic collisions of gas molecules with the resultant electrons serve to dissociate the gas. The gas is allowed to recombine downstream, with the recombination energy heating the gas. The hot gas is expanded through a nozzle to produce thrust. Molecular hydrogen, with a theoretical specific impulse of 2100 s (100% conversion), is the most attractive propellant. Sample calculations on a hydrogen thruster for a thrust of 1 N and a specific impulse of 1500 s yield the following results: mass flow rate, 6.8xlO~ 5 kg/s; minimum input power, 7.3 kW; minimum flow area (nozzle throat), 4x 10 ~2 to 4x 10 ~4 m2 for pressures of 13.3 to 1330 N/m2, respectively; and thrust densities of the order of 100 N/m2. Attractive features of the free radical propulsion concept in comparison to electrostatic ion propulsion or similar systems are increased thrust, thrust density, and thrust-to-power ratio.
Neutrosophic set - a generalization of the intuitionistic fuzzy set

In this paper one generalizes the intuitionistic fuzzy set (IFS), paraconsistent set, and intuitionistic set to the neutrosophic set (NS). Many examples are presented. Distinctions between NS and IFS are underlined.
GUTs and exceptional branes in F-theory — II. Experimental predictions

We consider realizations of GUT models in F-theory. Adopting a bottom up approach, the assumption that the dynamics of the GUT model can in principle decouple from Planck scale physics leads to a surprisingly predictive framework. An internal U(1) hypercharge flux Higgses the GUT group directly to the MSSM or to a flipped GUT model, a mechanism unavailable in heterotic models. This new ingredient automatically addresses a number of puzzles present in traditional GUT models. The internal U(1) hyperflux allows us to solve the doublet-triplet splitting problem, and explains the qualitative features of the distorted GUT mass relations for lighter generations due to the Aharanov-Bohm effect. These models typically come with nearly exact global symmetries which prevent bare ? terms and also forbid dangerous baryon number violating operators. Strong curvature around our brane leads to a repulsion mechanism for Landau wave functions for neutral fields. This leads to large hierarchies of the form exp(?c/?2?) where c and ? are order one parameters and ? ~ ?GUT?1MGUT/Mpl. This effect can simultaneously generate a viably small ? term as well as an acceptable Dirac neutrino mass on the order of 0.5 ? 10?2?0.5 eV. In another scenario, we find a modified seesaw mechanism which predicts that the light neutrinos have masses in the expected range while the Majorana mass term for the heavy neutrinos is ~ 3 ? 1012?1.5 GeV. Communicating supersymmetry breaking to the MSSM can be elegantly realized through gauge mediation. In one scenario, the same repulsion mechanism also leads to messenger masses which are naturally much lighter than the GUT scale.
Alcohol-Related Help-Seeking in Problem Drinking Women Sexual Assault Survivors

In 2002-2003 correlates of alcohol-related help-seeking were studied in women sexual assault survivors who were current problem drinkers (N = 526) in a large metropolitan area. Volunteer participants completed several valid and reliable instruments (i.e., the TWEAK, GFM, and MAST), which assessed alcohol use and misuse and related help-seeking. Data were analyzed using logistic regression models. Results suggest that correlates of women survivors' alcohol-related help-seeking vary depending on the specific source. Limitations and implications are noted and recommendations for future research are made. This study was funded by the National Institutes on Alcohol Abuse and Alcoholism.
Efficient Assays for Combinatorial Methods for the Discovery of Catalysts.

The revolutionary developments in combinatorial approaches to pharmaceutical science are now being explored in such diverse areas as materials design and homogeneous and heterogeneous catalysis. The quest for more efficient and selective catalysts has created the desire to design parallel assays for catalytic activity in combinatorial studies. This contribution highlights some of the recent exciting developments in this area.
Asymmetric Diels-Alder reactions. Inverse electron demand reactions of esters of 3-hydroxypyran-2-one with vinyl ethers : use of high pressure to avoid decarboxylation of adducts

Abstract Asymmetric inverse electron-demand Diels-Alder reactions of esters of 3-hydroxypyran-2-one with vinyl ethers proceed under high pressure at ambient temperature, making isolation of the synthetically useful bicyclic adducts feasible. Investigation has revealed that the desired adduct can be synthesized with diastereofacial selectivity, up to 88:12, by reaction of the acetate of 3-hydroxypyran-2-one with chiral 8-(3.5-dimethylphenyl)menthyl vinyl ether.
Asymmetric Synthesis of β-Hydroxy Amino Acids via Aldol Reactions Catalyzed by Chiral Ammonium Salts

The Cinchona alkaloid derived chiral ammonium salt developed by Park and Jew functions as an effective catalyst for the synthesis of β-hydroxy α-amino acids via asymmetric aldol reactions under homogeneous conditions. The syn diastereomers are obtained in good ee, and aryl-substituted aliphatic aldehydes are the best substrates for the reaction. These results represent the highest ee's obtained to date in direct aldol reactions of glycine equivalents catalyzed by inexpensive, readily prepared chiral ammonium salts.
Limiting Moral Hazard and Reducing Risk in International Capital Flows: The Choice of an Exchange Rate Regime

The current consensus in the academic literature, endorsed by the International Monetary Fund (IMF) and other international organizations, is that one of the main lessons of recent financial crises in East Asia and Latin America is the need for more flexible exchange rate arrangements. Stanley Fischer, the Deputy Managing Director of the International Monetary Fund, stated the matter thus
Equilibrium theory under ambiguity

Abstract We extend the classical results on the Walras–core existence and equivalence to an ambiguous asymmetric information economy; that is, an economy where agents maximize Maximin Expected Utility (MEU). The interest of considering ambiguity arises from the fact that, in the presence of MEU decision making, there is no conflict between efficiency and incentive compatibility (contrary to the Bayesian decision making). Our new modeling of an ambiguous asymmetric information economy necessitates new equilibrium notions, which are always efficient and incentive compatible.
Applications of SIMD computers in signal processing

This paper analyzes in detail how far the proposed Single Instruction Multiple Data (SIMD) computers with interconnection networks are applicable in the signal processing area. Decimation in the time radix-2 fast Fourier transform (FFT) algorithm is considered here for implementation in a multiprocessor system with shared bus and an SIMD computer with interconnection network.Results are derived for data allocation, interprocessor communication, approximate computation time, speedup, and cost effectiveness for an N-point FFT with any P available processors. Further generalization is obtained for a radix-r FFT algorithm. N X N point, two-dimensional discrete Fourier transform (DFT) implementation is also considered, with one or more rows of input matrix allocated to each processor.Various curves are plotted and a comparison in performance is carried out between a shared-bus multiprocessor and SIMD computer with interconnection network. It is shown that the latter gives much higher speedup for P > 16 and is more cost-effective even with the high cost of switches. N, P and r, considered here, are all powers of 2.
Quantum data hiding

We expand on our work on quantum data hiding - hiding classical data among parties who are restricted to performing only local quantum operations and classical communication (LOCC). We review our scheme that hides one bit between two parties using Bell (1964) states, and we derive upper and lower bounds on the secrecy of the hiding scheme. We provide an explicit bound showing that multiple bits can be hidden bitwise with our scheme. We give a preparation of the hiding states as an efficient quantum computation that uses at most one ebit of entanglement. A candidate data-hiding scheme that does not use entanglement is presented. We show how our scheme for quantum data hiding can be used in a conditionally secure quantum bit commitment scheme.
Terahertz metamaterials on free-standing highly-flexible polyimide substrates

We have fabricated resonant terahertz metamaterials on free-standing polyimide substrates. The low-loss polyimide substrates can be as thin as 5.5??m yielding robust large-area metamaterials which are easily wrapped into cylinders with a radius of a few millimeters. Our results provide a path forward for creating multi-layer non-planar metamaterials at terahertz frequencies.
Identification‐Robust Minimum Distance Estimation of the New Keynesian Phillips Curve

Limited-information identification-robust methods on the indexation and price rigidity parameters of the New Keynesian Phillips Curve yield very wide confidence intervals. Full-information methods impose more restrictions on the reduced-form dynamics and thus make more efficient use of the information in the data. However, such methods are also subject to weak instrument problems. We propose identification-robust minimum distance methods for exploiting these additional restrictions and show that they yield considerably smaller confidence intervals for the coefficients of the model compared to their limited-information generalized method of moments counterparts. In contrast to previous studies, we find evidence of partial but not full indexation, and obtain sharper inference on the degree of price stickiness. However, this parameter remains weakly identified.
Polymer Coating of Glass Microballoons Levitated in a Focused Acoustic Field

Inertial confinement fusion (ICF) glass microballoons (GMBs) levitated in a focusing radiator acoustic device can be coated with liquid materials by deploying the liquid into the levitation field with a stepped-horn atomizer. The GMB can be forced to the center of the coating liquid with a strong acoustically generated centering force. Water solutions of organic polymers, uv-curable liquid organic monomers, and paraffin waxes have been used to prepare solid coatings on the surface of GMBs using this technique.
The Modernity of Premodern Islam in Contemporary Daghestan

This ethnographic essay investigates the relations between past and present forms of Islam in the north Caucasian Republic of Daghestan. Conversations culled from fieldwork in Daghestani urban and rural spaces are used to elucidate the cultural, religious, and linguistic diversity of life in this region. Ethnographies in a bookstore, a shrine to the Imam Shamil, and a scholarly archive in Makhachkala unfold against the historical background of Daghestan’s long-standing encounter with the Arabo-Islamic world. The essay explores how the post-Soviet turn to post-secular Islam represents an alternative to colonialism and a new way of making meaning in the present. It is intended as a contribution to Islamic studies, modernity theory, and post-Soviet Union area studies.
Technical Note: Bias and the Quantification of Stability

Research on bias in machine learning algorithms has generally been concerned with the impact of bias on predictive accuracy. We believe that there are other factors that should also play a role in the evaluation of bias. One such factor is the stability of the algorithms in other words, the repeatability of the results. If we obtain two sets of data from the same phenomenon, with the same underlying probability distribution, then we would like our learning algorithm to induce approximately the same concepts from both sets of data. This paper introduces a method for quantifying stability, based on a measure of the agreement between concepts. We also discuss the relationships among stability, predictive accuracy, and bias.
Fresnel coefficients for a phase conjugator

Optical phase conjugation by four-wave mixing is examined in detail. The Fresnel coefficients for reflection and transmission of a plane wave irradiating the surface of the phase conjugator are calculated. It appears that for normal incidence and a weak nonlinear interaction the device produces the phase-conjugated beam with respect to the incoming beam. For finite angles of incidence or stronger nonlinearities in the crystal, the generated wave deviates from the ideal conjugated wave, and also a second, specularly reflected, wave appears.
A Momentous Arrow of Time

Quantum cosmology offers a unique stage to address questions of time related to its underlying (and perhaps truly quantum dynamical) meaning as well as its origin. Some of these issues can be analyzed with a general scheme of quantum cosmology, others are best seen in loop quantum cosmology. The latters status is still incomplete, and so no full scenario has yet emerged. Nevertheless, using properties that have a potential of pervading more complicated and realistic models, a vague picture shall be sketched here. It suggests the possibility of deriving a beginning within a beginningless theory, by applying cosmic forgetfulness to an early history of the universe.
International Coordination of Central Bank Policy

This paper surveys the current state of the literature on international monetary policy coordination. It relates recent policy discussions to the lessons from the literature. It proposes several avenues for future research.
Target-finding time for microtubules interacting with catastrophe-suppressing drugs

The target-finding time for microtubules interacting with catastrophe-suppressing drugs is investigated in this study. In the steady state of microtubules interacting with catastrophe-suppressing drugs, two types of microtubules exist, those with and those without drug tips. This work shows that microtubules in the first group are slower in finding a target than those in the second group. This result is consistent with experimental findings.PACS Nos.: 87.16.Ka, 87.16.Ac, 87.10.+e, 87.15.Rn
Single‐molecule imaging of protein adsorption mechanisms to surfaces

Protein-surface interactions cause the desirable effect of controlled protein adsorp- tion onto biodevices as well as the undesirable effect of protein fouling. The key to controlling pro- tein-surface adsorptions is to identify and quantify the main adsorption mechanisms: adsorptions that occur (1) while depositing a protein solution onto dry surfaces and (2) after the deposition onto wet surfaces. Bulk measurements cannot reveal the dynamic protein adsorption pathways and thus cannot differentiate between the two adsorption mechanisms. We imaged the interactions of single streptavidin molecules with hydrophobic fused-silica surfaces in real-time. We observed both adsorbed proteins on surfaces and diffusing proteins near surfaces and analyzed their adsorption kinetics. Our analysis shows that the protein solution deposition process is the primary mechanism of streptavidin adsorption onto surfaces at the subnanomolar to nanomolar protein concentrations. Furthermore, we found that hydrophilic fused-silica surfaces can prevent the adsorption of streptavidin molecules. Microsc. Res. Tech. 74:682-687, 2011. V V C 2010 Wiley-Liss, Inc.
Theoretical Spectra and Atmospheres of Extrasolar Giant Planets

We present a comprehensive theory of the spectra and atmospheres of irradiated extrasolar giant planets. We explore the dependences on stellar type, orbital distance, cloud characteristics, planet mass, and surface gravity. Phase-averaged spectra for specific known extrasolar giant planets that span a wide range of the relevant parameters are calculated, plotted, and discussed. The connection between atmospheric composition and emergent spectrum is explored in detail. Furthermore, we calculate the effect of stellar insolation on brown dwarfs. We review a variety of representative observational techniques and programs for their potential for direct detection, in light of our theoretical expectations, and we calculate planet-to-star flux ratios as a function of wavelength. Our results suggest which spectral features are most diagnostic of giant planet atmospheres and reveal the best bands in which to image planets of whatever physical and orbital characteristics.
Lyapunov stability theory of nonsmooth systems

This paper develops nonsmooth Lyapunov stability theory and LaSalle's invariance principle for a class of nonsmooth Lipschitz continuous Lyapunov functions and absolutely continuous state trajectories. Computable tests based on Filipov's differential inclusion and Clarke's generalized gradient are derived. The primary use of these results is in analyzing the stability of equilibria of differential equations with discontinuous right-hand side such as in nonsmooth dynamic systems or variable structure control. >
Distributed rendering of interactive soft shadows

Recently several distributed rendering systems have been developed that exploit a cluster of commodity computers by connecting host graphics cards over a fast network to form a compositing pipeline. This paper introduces an algorithm for one such system to parallelize contributions from arbitrary numbers of OpenGL lights, for example to compute approximate soft shadows by sampling area light sources. The algorithm renders multiple shadow maps across nodes of the cluster by factoring the OpenGL lighting equation into illumination and material properties. Additional parallelism is achieved by utilizing multiple texture units within each graphics card. Illumination by L point sources can be rendered by (L/K) + 1 nodes where K is the number of texture units on each graphics card. For walkthrough applications each node requires a single rendering pass, while for scenes with dynamic lights or geometry K+ 1 passes are needed per node. We present results using fragment shaders on nVidia Ge- Force4 Ti4600 and ATI Radeon 8500 graphics cards, and a cycle-accurate simulation of the compositing operators. These results show interactive frame rates for walkthroughs and dynamic models rendering shadows with 32 light sources on 9 nodes of a Sepia-2a distributed rendering cluster.
Terahertz quantum-cascade lasers

Six years after their birth, terahertz quantum-cascade lasers can now deliver milliwatts or more of continuous-wave coherent radiation throughout the terahertz range — the spectral regime between millimetre and infrared wavelengths, which has long resisted development. This paper reviews the state-of-the-art and future prospects for these lasers, including efforts to increase their operating temperatures, deliver higher output powers and emit longer wavelengths.
Vertical Equity Consequences of Very High Cigarette Tax Increases: If the Poor Are the Ones Smoking, How Could Cigarette Tax Increases Be Progressive?.

Cigarette smoking is concentrated among low-income groups. Consequently, cigarette taxes are considered regressive. However, if poorer individuals are much more price sensitive than richer individuals, then tax increases would reduce smoking much more among the poor and their cigarette tax expenditures as a share of income would rise by much less than for the rich. Warner (2000) said this phenomenon would make cigarette tax increases progressive. We test this empirically. Among low-, middle-, and high-income groups, we estimate total price elasticities of _0.37, _0.35, and _0.20, respectively. We find that cigarette tax increases are not close to progressive, using both tax expenditure-based and traditional welfare measures. This finding is robust to cross-border purchasing, generic cigarettes, and substantial external effects. However, we find that taxes can be progressive under some behavioral economic models (Gruber & Koszegi, 2004) but that these may only apply to a small share of smokers. © 2008 by the Association for Public Policy Analysis and Management.
Braneworld gravity: influence of the moduli fields

We consider the case of a generic braneworld geometry in the presence of one or more moduli fields (e.g. the dilaton) that vary throughout the bulk spacetime. Working in an arbitrary conformal frame, using the generalized junction conditions of gr-qc/0008008 and the Gauss-Codazzi equations, we derive the effective ``induced'' on-brane gravitational equations. As usual in braneworld scenarios, these equations do not form a closed system in that the bulk can exchange both information and stress-energy with the braneworld. We work with an arbitrary number of moduli fields described by an arbitrary sigma model, with arbitrary curvature couplings, arbitrary self interactions, and arbitrary dimension for the bulk. (The braneworld is always codimension one.) Among the novelties we encounter are modifications of the on-brane stress-energy conservation law, anomalous couplings between on-brane gravity and the trace of the on-brane stress-energy tensor, and additional possibilities for modifying the on-brane effective cosmological constant. After obtaining the general stress-energy ``conservation'' law and the ``induced Einstein equations'' we particularize the discussion to two particularly attractive cases: for a (n−2)-brane in ([n−1] + 1) dimensions we discuss both the effect of (1) generic variable moduli fields in the Einstein frame, and (2) the effect of a varying dilaton in the string frame.
Internet indirection infrastructure

Attempts to generalize the Internet's point-to-point communication abstraction to provide services like multicast, anycast, and mobility have faced challenging technical problems and deployment barriers. To ease the deployment of such services, this paper proposes a general, overlay-based Internet Indirection Infrastructure (i3) that offers a rendezvous-based communication abstraction. Instead of explicitly sending a packet to a destination, each packet is associated with an identifier; this identifier is then used by the receiver to obtain delivery of the packet. This level of indirection decouples the act of sending from the act of receiving, and allows i3 to efficiently support a wide variety of fundamental communication services. To demonstrate the feasibility of this approach, we have designed and built a prototype based on the Chord lookup protocol.
Markov equilibria in a model of bargaining in networks

Abstract We study the Markov perfect equilibria (MPEs) of an infinite horizon game in which pairs of players connected in a network are randomly matched to bargain. Players who reach agreement are removed from the network without replacement. We establish the existence of MPEs and show that MPE payoffs are not necessarily unique. A method for constructing pure strategy MPEs for high discount factors is developed. For some networks, we find that all MPEs are asymptotically inefficient as players become patient.
A new free radical-based method for the synthesis of spiroannulated medium rings

Abstract Free radical promoted cyclobutanone ring expansion provides a new entry to a variety of spiroannulated ring systems.
Channel access using opportunistic reservations and virtual MIMO

We propose ORCHESTRA, a channel-access protocol that uses reservations and virtual MIMO to provide high throughput and bounded channel-access delays. The channel-access process is divided into a contention-based access period and a scheduled access period. To attain high throughput, nodes build a channel schedule using the contention-based access period, and utilize the spatial multiplexing gain of virtual MIMO links in the scheduled access period. To attain bounded channel-access delays, nodes reserve time slots through opportunistic reservations. We evaluate the performance of ORCHESTRA through numerical analysis and simulations, and show that it results in much better throughput, delay, and jitter characteristics that simply using MIMO nodes together with scheduled access (i.e., NAMA) or contention-based access (i.e., IEEE 802.11 DCF).
The connection between shear and star formation in spiral galaxies

We present a sample of 33 galaxies for which we have calculated (i) the average rate of shear from published rotation curves, (ii) the far-infrared luminosity from IRAS fluxes, and (iii) the K-band luminosity from the Two Microm All Sky Survey (2MASS). We show that a correlation exists between the shear rate and the ratio of the far-infrared to K-band luminosity. This ratio is essentially a measure of the star formation rate per unit mass, or specific star formation rate. From this correlation we show that a critical shear rate exists, above which star formation would turn off in the discs of galaxies. Using the correlation between shear rate and spiral arm pitch angle, this shear corresponds to the lowest pitch angles typically measured in near-infrared images of spiral galaxies.
Partisanship, Political Control, and Economic Assessments

Previous research shows that partisans rate the economy more favorably when their party holds power. There are several explanations for this association, including use of different evaluative criteria, selective perception, selective exposure to information, correlations between economic experiences and partisanship, and partisan bias in survey responses. We use a panel survey around the November 2006 election to measure changes in economic expectations and behavioral intentions after an unanticipated shift in political power. Using this design, we can observe whether the association between partisanship and economic assessments holds when some leading mechanisms thought to bring it about are excluded. We find that there are large and statistically significant partisan differences in how economic assessments and behavioral intentions are revised immediately following the Democratic takeover of Congress. We conclude that this pattern of partisan response suggests partisan differences in perceptions of the economic competence of the parties, rather than alternative mechanisms.
Euclidean distortion and the sparsest cut

We prove that every $n$-point metric space of negative type (and, in particular, every $n$-point subset of $L_1$) embeds into a Euclidean space with distortion $O(\sqrt{\log n} \cdot\log \log n)$, a result which is tight up to the iterated logarithm factor. As a consequence, we obtain the best known polynomial-time approximation algorithm for the Sparsest Cut problem with general demands. Namely, if the demand is supported on a subset of size $k$, we achieve an approximation ratio of $O(\sqrt{\log k}\cdot \log \log k)$.
A Search for Magnesium in Europa's Atmosphere

Europa's tenuous atmosphere results from sputtering of the surface. The trace element composition of its atmosphere is therefore related to the composition of Europa's surface. Magnesium salts are often invoked to explain Galileo Near Infrared Mapping Spectrometer spectra of Europa's surface, thus magnesium may be present in Europa's atmosphere. We have searched for magnesium emission in the Hubble Space Telescope Faint Object Spectrograph archival spectra of Europa's atmosphere. Magnesium was not detected and we calculate an upper limit on the magnesium column abundance. This upper limit indicates that either Europa's surface is depleted in magnesium relative to sodium and potassium, or magnesium is not sputtered as efficiently resulting in a relative depletion in its atmosphere.
Using Stellar Limb-Darkening to Refine the Properties of HD 209458b

We use multiband photometry to refine estimates for the planetary radius and orbital inclination of the transiting planet system HD 209458. We gathered 1066 spectra over four distinct transits with the STIS spectrometer on the Hubble Space Telescope using two gratings with a resolution R = 1500 and a combined wavelength range of 290-1030 nm. We divide the spectra into 10 spectrophotometric bandpasses, five for each grating, of equal wavelength span within each grating, and fit a transit curve over all bandpasses simultaneously. In our fit we use theoretical values for the stellar limb-darkening to further constrain the planetary radius. We find that the radius of HD 209458b is (1.320 ± 0.025)R_(Jup), which is a factor of 2 more precise than current estimates. We also obtain improved estimates for the orbital period P and time of center of transit T_C. Although in principle the photon-limited precision of the STIS data should allow us to measure the timing of individual transits to a precision of 2-7 s, we find that uncertainties in the stellar limb-darkening coefficients and residual noise in the data degrade these measurements to a typical precision of ±14 s. Within this level of error, we find no significant variations in the timing of the eight events examined in this work.
The longitudinal response function of the deuteron in chiral effective field theory

We use chiral effective field theory (χEFT) to make predictions for the longitudinal electromagnetic response function of the deuteron, f L , which is measured in d(e, e′N) reactions. In this case the impulse approximation gives the full χEFT result up to $$\mathcal{O}(P^4 )$$ relative to leading order. By varying the cutoff in the χEFT calculation between 0.6 and 1 GeV we conclude that the calculation is accurate to better than 10% for values of q 2 within 4 fm−2 of the quasi-free peak, up to final-state energies E np = 60 MeV. In these regions χEFT is in reasonable agreement with predictions for f L obtained using the Bonn potential. We also find good agreement with existing experimental data on f L , albeit in a more restricted kinematic domain.
Preference, Value, Choice, and Welfare

This book is about preferences, principally as they figure in economics. It also explores their uses in everyday language and action, how they are understood in psychology and how they figure in philosophical reflection on action and morality. The book clarifies and for the most part defends the way in which economists invoke preferences to explain, predict and assess behavior and outcomes. Hausman argues, however, that the predictions and explanations economists offer rely on theories of preference formation that are in need of further development, and he criticizes attempts to define welfare in terms of preferences and to define preferences in terms of choices or self-interest. The analysis clarifies the relations between rational choice theory and philosophical accounts of human action. The book also assembles the materials out of which models of preference formation and modification can be constructed, and it comments on how reason and emotion shape preferences.
Stereoselective alkylation of allylic alcohols: Tandem ethylation and functionalization

The allylic alcohols incorporate an ethylene unit from Grignard (II) in the presence of the Ti reagent.
Modeling the low-latitude thermosphere and ionosphere

The National Center for Atmospheric Research thermosphere=ionosphere=electrodynamic general circulation model (TIEGCM) is one of the few models that self-consistently solves the coupled equations for the neutral atmosphere and ionosphere. Timely questions are how well the TIEGCM currently simulates the low-latitude ionosphere and what modi9cations might bring about better predictions. Comparisons between data obtained in and around Jicamarca, Peru, near the magnetic equator, and simulations with the TIEGCM indicate good progress has been made but reveal some serious discrepancies. Good-to-excellent agreement is obtained for electron densities, electron and ion temperatures, and nmax. The agreement is fair to poor for hmax, zonal drifts, the 630 nm oxygen nightglow, and the horizontal neutral winds. The most important discrepancy is in the simulated neutral temperature, which is at least 100 K too cold relative to Fabry–Perot interferometer observations. Increasing the EUV ?uxes in the model to improve prediction of the model temperature also improves representation of airglow observations and of the ionosphere, for which the model typically underrepresents the electron densities. The disparity in neutral temperature is also present in comparisons with the empirical model MSIS which represents the largest database of thermospheric temperature measurements. Since the neutral and ionized atmospheres are tightly coupled at low latitudes, simultaneous measurements of neutral and ion parameters, preferably over an extended time period, would be invaluable to further the understanding of the region. Better knowledge of the EUV ?uxes and the high altitude O + ?uxes may also help
Chernoff bounds on pairwise error probabilities of space-time codes

We derive Chernoff bounds on pairwise error probabilities of coherent and noncoherent space-time signaling schemes. First, general Chernoff bound expressions are derived for a correlated Ricean fading channel and correlated additive Gaussian noise. Then, we specialize the obtained results to the cases of space-time-separable noise, white noise, and uncorrelated fading. We derive approximate Chernoff bounds for high and low signal-to-noise ratios (SNRs) and propose optimal signaling schemes. We also compute the optimal number of transmitter antennas for noncoherent signaling with unitary mutually orthogonal space-time codes.
Preferences for One-Shot Resolution of Uncertainty and Allais-Type Behavior

Experimental evidence suggests that individuals are more risk averse when they perceive risk gradually. We address these …ndings by studying a decision maker (DM) who has recursive preferences over compound lotteries and who cares about the way uncertainty is resolved over time. DM has preferences for one-shot resolution of uncertainty (PORU) if he always prefers any compound lottery to be resolved in a single stage. We establish an equivalence between dynamic PORU and static preferences that are identi…ed with the behavior observed in Allais-type experiments. The implications of this equivalence on preferences over information systems are examined. � �
Biomass feedstocks for renewable fuel production: a review of the impacts of feedstock and pretreatment on the yield and product distribution of fast pyrolysis bio-oils and vapors

Renewable transportation fuels from biomass have the potential to substantially reduce greenhouse gas emissions and diversify global fuel supplies. Thermal conversion by fast pyrolysis converts up to 75% of the starting plant material (and its energy content) to a bio-oil intermediate suitable for upgrading to motor fuel. Woody biomass, by far the most widely-used and researched material, is generally preferred in thermochemical processes due to its low ash content and high quality bio-oil produced. However, the availability and cost of biomass resources, e.g. forest residues, agricultural residues, or dedicated energy crops, vary greatly by region and will be key determinates in the overall economic feasibility of a pyrolysis-to-fuel process. Formulation or blending of various feedstocks, combined with thermal and/or chemical pretreatment, could facilitate a consistent, high-volume, lower-cost biomass supply to an emerging biofuels industry. However, the impact of biomass type and pretreatment conditions on bio-oil yield and quality, and the potential process implications, are not well understood. This literature review summarizes the current state of knowledge regarding the effect of feedstock and pretreatments on the yield, product distribution, and upgradability of bio-oil.
Jet correlation measurement in heavy-ion collisions: from RHIC to LHC

We attempt to deduce simple options of 'jet quenching' phenomena in heavy-ion collisions at √sNN = 5.5 TeV at the LHC from the present knowledge of leading-hadron suppression at RHIC energies. In light of the nuclear modification factor for leading particles we introduce the nuclear modification factor for jets, RjetAA, and for the longitudinal momenta of particles along the jet axis, RpLAA.
Evidence in the auroral record for secular solar variability

The historial record of aurorae is continuous and usefully dense for at least the 2000 years. Revival of interest in the secular variability in solar activity motivates a review of the auroral record. The existence of secular variations in the auroral occurrence frequency has been known since the early 1700's, including the existence of a significant attenuation of auroral activity during the Maunder Minimum. Investigation of secular variations prior to the Maunder Minimum is now possible based on six auroral catalogs that have been published within the last 20 years. The catalogs cover the time period from the fifth century B.C. to the seventeenth century A.D. and combine both oriental and European obsertions. Features corresponding to the previously recognized Medieval Minimum, Medieval Maximum, and the Spoerer Minimum are clearly evident in both oriental and European records. The global synchronicity of anomalies in the auroral occurrence frequency is used to argue that they are caused by changes in the level or state of solar activity. The combined catalogs provide a sufficient number of events in the Middle Ages to resolve a quasi-80-year periodicity in the recorded auroral occurrence frequency. Also in the unusually rich intervals of the Middle Ages, clear quasi-10-yearmore » periodicities appear in the recorded occurrence frequency wave from. These are most reasonably interpreted as manifestations of the 11-year solar cycle and indicate that the solar cycle was then operative.« less
Catalytic enantioselective construction of all-carbon quaternary stereocenters: synthetic and mechanistic studies of the C-acylation of silyl ketene acetals.

With the aid of an appropriate chiral catalyst, acyclic silyl ketene acetals react with anhydrides to furnish 1,3-dicarbonyl compounds that bear all-carbon quaternary stereocenters in good ee and yield. Mechanistic studies provide strong support for a catalytic cycle that involves activation of both the electrophile (anhydride → acylpyridinium) and the nucleophile (silyl ketene acetal → enolate).
High-current relativistic klystron amplifier development for microsecond pulse lengths

The performance of the Friedman-type high-current relativistic klystron amplifier (RKA) is being extended to the microsecond regime while attempting to achieve the gigawatt-level peak power capability that has been characteristic of the RKA at shorter pulse lengths. Currently the electron beam power into the device is about 1 GW in microsecond duration pulses, with an effort underway to increase the beam power to 2.5 GW. To date the device has yielded an RF-modulated electron beam power of 350 MW, with up to 50 MW coupled into waveguide. Several aspects of RKA operation under investigation that affect RKA beam bunching efficiency and amplifier gain include cavity tuning, beam diameter, beam current, and input RF drive power, and the development of an output coupler that efficiently couples the microwave power from the low-impedance beam into the rectangular waveguide operating in the dominant mode. Current results from experimental testing and code modeling are presented. >
Calixarenes and calix[4]resorcinarenes as chiral NMR solvating agents

Calixarenes (CAs) and calix[4]resorcinarenes are cavity compounds, chiral analogues of which have the potential to be used as reagents for the differentiation of enantiomers in NMR spectroscopy. The nature of the substituent groups attached to the cavity permits the preparation of organic- or water-soluble analogues. In NMR applications, chirality of the CAs or calix[4]resorcinarene is usually achieved through the attachment of enantiomerically pure substituent groups. The use of inherently chiral analogues for chiral differentiation is less common. The range of CAs and calix[4]resorcinarenes that have been used for chiral analysis in NMR spectroscopy is reviewed.
WITCHCRAFT, BUREAUCRAFT, AND THE SOCIAL LIFE OF (US)AID IN HAITI

In this article I discuss the unintended consequences of humanitarian and development assistance provided to “victims of human rights abuses” in Haiti in the years following the restoration of democracy in 1994. Such targeted aid was a component of international political and economic development aid intended to facilitate the nation's postconflict transition. I argue that in much the same manner that witchcraft discourses signify moral struggles over the distribution of resources in small-scale societies, the cultures and moral economies of humanitarian and development aid—well-intentioned activities that nonetheless include opaque bureaucratic practices and competition over knowledge, scarce resources, and institutional territory—can produce similar phenomena as has been described regarding contemporary witchcraft. I draw on the literature on witchcraft, bureaucracy, and secrecy to analyze accusations of malfeasance, scapegoating, and violence directed toward both providers and recipients of humanitarian and development assistance. I characterize such processes occurring in relation to compassion economies by the term bureaucraft. [witchcraft, bureaucracy, bureaucraft, humanitarianism, democracy, insecurity, human rights, Haiti]
Effect of Acknowledgment Traffic on the Performance of Slotted ALOHA-Code Division Multiple Access Systems

Use of code division multiple access (CDMA) in conjunction with slotted ALOHA improves throughput, since some of the "collided" packets can be retrieved, although at the expense of enlarged bandwidth. In view of the feasibility of recovery of packets, such schemes are attractive to carry receiver-to-transmitter acknowledgment (ACK) traffic also. The presence of ACK traffic is known to significantly reduce the throughput of slotted ALOHA channels. In this correspondence, the impact of such ACK traffic on the performance of slotted ALOHACDMA schemes is examined in detail for both finite and infinite terminal population.
A statistical model for word discovery in transcribed speech

A statistical model for segmentation and word discovery in continuous speech is presented. An incremental unsupervised learning algorithm to infer word boundaries based on this model is described. Results are also presented of empirical tests showing that the algorithm is competitive with other models that have been used for similar tasks.
The 67 Hz Feature in the Black Hole Candidate GRS 1915+105 as a Possible Diskoseismic Mode

The Rossi X-Ray Timing Explorer has made feasible for the first time the search for high-frequency (greater than or equal to 100 Hz) periodic features in Black Hole Candidate (BHC) systems. Such a feature, with a 67 Hz frequency, recently has been discovered in the BHC GRS 1915+105 (Morgan, Remillard, & Greiner). This feature is weak (rms variability approx. 0.3%-1.6%), stable in frequency (to within approx. 2 Hz) despite appreciable luminosity fluctuations, and narrow (quality factor Q approx. 20). Several of these properties are what one expects for a 'diskoseismic' g-mode in an accretion disk about a 10.6 M(solar mass) (nonrotating) to 36.3 M(solar mass) (maximally rotating) black hole (if we are observing the fundamental-mode frequency). We explore this possibility by considering the expected luminosity modulation, as well as possible excitation and growth mechanisms-including turbulent excitation, damping, and 'negative' radiation damping. We conclude that a diskoseismic interpretation of the observations is viable.
The Euler–Poincaré Equations and Semidirect Products with Applications to Continuum Theories

We study Euler–Poincare systems (i.e., the Lagrangian analogue of Lie–Poisson Hamiltonian systems) defined on semidirect product Lie algebras. We first give a derivation of the Euler–Poincare equations for a parameter dependent Lagrangian by using a variational principle of Lagrange d'Alembert type. Then we derive an abstract Kelvin–Noether theorem for these equations. We also explore their relation with the theory of Lie–Poisson Hamiltonian systems defined on the dual of a semidirect product Lie algebra. The Legendre transformation in such cases is often not invertible; thus, it does not produce a corresponding Euler–Poincare system on that Lie algebra. We avoid this potential difficulty by developing the theory of Euler–Poincare systems entirely within the Lagrangian framework. We apply the general theory to a number of known examples, including the heavy top, ideal compressible fluids and MHD. We also use this framework to derive higher dimensional Camassa–Holm equations, which have many potentially interesting analytical properties. These equations are Euler–Poincare equations for geodesics on diffeomorphism groups (in the sense of the Arnold program) but where the metric is H^1 rather thanL^2.
POLYNOMIAL CUBIC DIFFERENTIALS AND CONVEX POLYGONS IN THE PROJECTIVE PLANE

We construct and study a natural homeomorphism between the moduli space of polynomial cubic dierentials of degree d on the complex plane and the space of projective equivalence classes of ori- ented convex polygons with d + 3 vertices. This map arises from the construction of a complete hyperbolic ane sphere with prescribed Pick dierential, and can be seen as an analogue of the Labourie-Loftin pa- rameterization of convex RP 2 structures on a compact surface by the bundle of holomorphic cubic dierentials over Teichmuller space.
Compositions of Projections in Banach Spaces and Relations Between Approximation Properties

A necessary and sucient condition for existence of a Banach space with a finite dimensional decomposition but without the -property in terms of norms of com- positions of projections is found.
A Convenient Synthesis of the Orthogonally-Protected Benzodiazepine-2,5-Dione Scaffold

Abstract We have identified the benzodiazepine-2,5-dione 4 as a convenient, orthogonally-protected template, suitable for parallel solid-phase chemistry. Scaffold 4 offers superior stability, compared to other, analogous benzodiazepine-2,5-diones, such as A. We describe a gram-scale synthesis of 4 in six steps and in 25% yield.
Equity Links and Information Acquisition in Biotechnology Alliances

Abstract We use a simple model of collaborative innovation to structure an empirical analysis of minority equity links in biotechnology alliances between clients and R&D firms. In the model, an equity link is an investment in information acquisition: it improves the ability of the client to learn about the R&D firm's ability and the alliance project's quality. The model generates several testable hypotheses about how the R&D firm's project characteristics and previous alliances affect the use of equity links in new alliances. We test the hypotheses using a large data set of biotechnology alliances and find empirical support.