cssi/SciSciGPT-SciSciNet huggingface dataset:
An alternative test of the hedonic theory of housing markets

Abstract In this paper the hedonic theory of housing markets is used to generate a multinomial logit model of household behavior in an urban housing market. Application of hedonic theory to housing markets is by now fairly familiar and a link to multinomial logit has also been established. However, by emphasizing more heavily the bid price interpretation of hedonic theory, this paper develops a new connection to econometric estimation that essentially involves running the usual logit equations in reverse. One advantage of this approach is that the link between the logit equations and hedonic theory involves bid price rather than utility functions, and this in turn permits the empirical results to be given an extremely clear interpretation. Furthermore, in contrast to the standard logit model, the extreme value distribution required to justify the estimation technique emerges endogenously as part of the analysis.
Image-like potentials at semiconductor and electrolyte surfaces

Abstract The potential felt by a charged particle near an electrolyte (or intrinsic semiconductor) — vacuum interface is calculated. The Poisson-Boltzmann equation is used to describe the mobile charge in both types of substrate together with a classical dielectric description of the aqueous medium (or filled valence band). For charge-surface separations greater than or equal to the inverse screening length in the substrate, a shifted image potential is obtained. The shift distance depends on the surface potential, screening length and dielectric constant of the material. The potential due to the compressibility of any charged molecular adsorbate layer (or conventional surface states) present is estimated and found to be small for a wide range of parameters.
Applications to Space Operations of Free-Flying, Controlled Streams of Liquids

Potential uses for free-flying, recoverable streams of liquids in space are identified. One application, where droplets are the radiating component of a lightweight thermal heat rejection system, has been studied previously by Mattick and Hertzberg. Other applications (i.e., systems for the disposal of surplus liquids) have already been used in space. New possibilities are also considered: a droplet aerobrake system, an orbital planetary gas accumulation system, a space material transport system, a method for remotely accomplishing space construction tasks using droplet streams, and a low-contamination attitude control or stationkeeping thruster. The proposed applications require that the streams have varied but generally high directional and speed stability. Charts summarizing liquid stream performance are presented. New experimental results extending the performance characteristics by an order of magnitude compared to previous observations are reported.
Oligodeoxyfluorosides: Strong Sequence Dependence of Fluorescence Emission

We describe the properties of a series of oligomeric polyfluorophores assembled on the DNA backbone. The eleven oligomers (oligodeoxyfluorosides, ODFs), 4 to 7 monomers in length, were composed of only two fluorescent monomers and a spacer in va ried sequences, and were designed to test how fluorescent nucleobases can interact electronically to yield complexity in fluorescence emission. The monomer fluorophores were deoxyribosides of pyrene and perylene, which emit light in violet and blue wavele ngths respectively. The experiments show that simple variation of sequence and spacing can dramatically change fluorescence, yielding emission maxima ranging from 380 to 557 nm and visible colors from violet to orange-red. Fluorescence lifetimes data, excitation spectra, and absorption data point to a number of multi-fluorophore electronic interactions, including pyrene-pyrene and perylene-perylene excimers, pyrene-perylene exciplexes, as well as monomer dye emissions, contributing to the final spectral outcomes. Thus, two simple fluorophores can be readily combined to give emissions over much of the visible spectrum, all requiring only a single excitation. The results demonstrate that fluorescent nucleobases in oligomeric form can act cooperatively as electronic units, and that fluorophore sequence in such oligomers is as important as fluorophore composition in determining fluorescence properties.
Asymmetric gluon distributions and hard diffractive electroproduction

Due to the momentum transfer r{equivalent_to} p{minus}p{prime} from the initial proton to the final, the asymmetric matrix element {l_angle}p{prime}{vert_bar}G...G{vert_bar}p{r_angle} that appears in the pQCD description of hard diffractive electroproduction does not coincide with that defining the gluon distribution function f{sub g}(x). The author outlines a pQCD formalism based on a concept of the double distribution F{sub g}(x,y), which specifies the fractions xp, yr, (1{minus}y)r of the initial proton momentum p and the momentum transfer r, resp., carried by the gluons. He discusses the one-loop evolution equation for the double distribution F{sub g}(x,y,{mu}) and obtains the solution of tis equation in simplified situation when the quark-gluon mixing effects are neglected. For r{sup 2}=0, the momentum transfer r is proportional to p: r = {zeta}p, and it is convenient to parameterize the matrix element {l_angle}p{minus}r{vert_bar}G...G{vert_bar}p{r_angle} by an asymmetric distribution function F{sub {zeta}}{sup g}(X) depending on the total fractions X {equivalent_to} x+y{zeta} and X{minus}{zeta} = x{minus}(1{minus}y){zeta} of the initial hadron momentum p carried by the gluons. He formulates evolution equations for F{sub {zeta}}{sup g}(X), studies some of their general properties and discusses the relationship between F{sub {zeta}}{sup g}(X), F{sub g}(x,y) and f{sub g}(x).
Powers in Lucas sequences via Galois representations

Let $u_n$ be a nondegenerate Lucas sequence. We generalize the results of Bugeaud, Mignotte, and Siksek, 2006 to give a systematic approach towards the problem of determining all perfect powers in any particular Lucas sequence. We then prove a general bound on admissible prime powers in a Lucas sequence assuming the Frey-Mazur conjecture on isomorphic mod $p$ Galois representations of elliptic curves.
The development of carbon–carbon bond forming reactions of aminal radicals

Abstract Aminal radicals were generated and used in synthetic reactions for the first time. Aminal radicals are formed from aminals by radical translocation using AIBN and a stoichiometric hydrogen atom donor, or by SmI2 reduction of N-acyl amidines or amidinium ions in the presence of a proton source. Aminal radicals were found to participate in inter- and intramolecular C–C bond forming reactions with electron deficient alkenes. Chemical yields were as high as 99%.
The relative importance of the distance senses in coyote predatory behaviour

Abstract The purpose of this study was to determine the relative importance of vision, audition and olfaction to hunting coyotes ( Canis latrans ). The durations required for five coyotes to locate rabbits in an enclosed room were measured. The visual, auditory and olfactory stimuli emitted by the rabbits were eliminated individually, in pairs, and altogether. Visual stimuli were eliminated by removing all visible light from the room. Auditory stimuli were eliminated by killing the rabbits prior to a test. Olfactory stimuli were blocked by a masking odour. The coyotes' preference for visual or auditory prey stimuli was also tested. The relative importance of these three senses in order of decreasing importance was concluded to be: vision, audition and olfaction.
Diastereomeric complex formation between a novel optically active host and naproxen in aqueous solution

Abstract The synthesis of the novel optically active macrocyclic host (+)- 1 incorporating an unnatural isoquinoline alkaloid as chiral building block is described. The formation of diastereomeric complexes between host (+)- 1 and (R) and (S)-naproxen in aqueous solution is observed by 1 H NMR spectroscopy.
Searching for the right word: Hybrid visual and memory search for words

In “hybrid search” (Wolfe Psychological Science, 23(7), 698-703, 2012), observers search through visual space for any of multiple targets held in memory. With photorealistic objects as the stimuli, response times (RTs) increase linearly with the visual set size and logarithmically with the memory set size, even when over 100 items are committed to memory. It is well-established that pictures of objects are particularly easy to memorize (Brady, Konkle, Alvarez, & Oliva Proceedings of the National Academy of Sciences, 105, 14325–14329, 2008). Would hybrid-search performance be similar if the targets were words or phrases, in which word order can be important, so that the processes of memorization might be different? In Experiment 1, observers memorized 2, 4, 8, or 16 words in four different blocks. After passing a memory test, confirming their memorization of the list, the observers searched for these words in visual displays containing two to 16 words. Replicating Wolfe (Psychological Science, 23(7), 698-703, 2012), the RTs increased linearly with the visual set size and logarithmically with the length of the word list. The word lists of Experiment 1 were random. In Experiment 2, words were drawn from phrases that observers reported knowing by heart (e.g., “London Bridge is falling down”). Observers were asked to provide four phrases, ranging in length from two words to no less than 20 words (range 21–86). All words longer than two characters from the phrase, constituted the target list. Distractor words were matched for length and frequency. Even with these strongly ordered lists, the results again replicated the curvilinear function of memory set size seen in hybrid search. One might expect to find serial position effects, perhaps reducing the RTs for the first (primacy) and/or the last (recency) members of a list (Atkinson & Shiffrin, 1968; Murdock Journal of Experimental Psychology, 64, 482–488, 1962). Surprisingly, we showed no reliable effects of word order. Thus, in “London Bridge is falling down,” “London” and “down” were found no faster than “falling.”
Relating badly to brands

Our commentary focuses on the negative pole of Park et al.'s Attachment–Aversion continuum. We argue that the distinction between positively- and negatively-valenced relationships matters, and open opportunities to further our knowledge about what makes a brand relationship “bad.” Two theoretical extensions are offered: (1) additional negativity dimensions beyond brand–self distance including pathology, power, and self- versus brand-focused emotionality; and (2) distinctions between neutrality and variations of emotional ambivalence “in the middle” of the Attachment–Aversion spectrum. Our call is for a science of negative relationships concerning the negative outcomes, processes, states, and attributes of consumers' relationships with brands.
Multi-Lepton Signals of Multiple Higgs Bosons

We identify and investigate novel multi-lepton signatures of extended Higgs sectors at the LHC in the guise of CP- and flavor-conserving two-Higgs-doublet models (2HDMs). Rather than designing individual searches tailored to specific 2HDM signals, we employ the combination of many exclusive multi-lepton search channels to probe the collective signal from the totality of production and decay processes. Multi-lepton signals of 2HDMs can arise from a variety of sources, including Standard Model-like production of the CP-even scalars, h and H, through gluon-fusion with h, H → ZZ (∗), or associated production with vector bosons or top quarks, with h, H → WW (∗) , ZZ (∗) , ττ. Additional sources include gluon-fusion production of the heavy CP-even scalar with cascade decays through the light CP-even scalar, the CP-odd scalar, A, or the charged scalar, H ±, such as H → hh, H → AA, H → H + H −, H → ZA, with A → Zh, ττ, H ± → Wh, and h → WW ∗ , ZZ ∗ , ττ. Altogether, the combined multi-lepton signal may greatly exceed that of the Standard Model Higgs boson and provides a sensitive probe of extended Higgs sectors over a wide range of parameters. As a proof of principle, we use a factorized mapping procedure between model parameters and signatures to determine multi-lepton sensitivities in four different flavor conserving 2HDM parameter spaces by simulating the acceptance times efficiency in 20 exclusive multi-lepton channels for 222 independent production and decay topologies that arise for four benchmark 2HDM spectra within each parameter space. A comparison of these sensitivities with the results of a multi-lepton search conducted by the CMS collaboration using 5 fb−1 of data collected from 7 TeV pp collisions yields new limits in some regions of 2HDM parameter space that have not previously been covered by other types of direct experimental searches.
The First Total Syntheses of Ircinol A, Ircinal A, and Manzamines A and D.

In 1986, Higa, Jefford, and co-workers reported the isolation of a structurally novel polycyclic alkaloid, manzamine A, 1, from a sponge harvested near the coast of Okinawa.1 The unique structure of 1 consists of a β-carboline heterocycle attached to a novel pentacyclic diamine core containing both eight- and thirteen-membered rings on a pyrrolo[2,3-i]isoquinoline framework. The cytotoxic activity (IC50 = 0.07 µg/mL against P-388 mouse leukemia cells) and unique structure of 1 have stimulated considerable interest and activity directed toward the total synthesis of manzamine A which has not yet been successfully achieved to date.2 The intramolecular vinylogous amide photoaddition/fragmentation/Mannich closure sequence that we have developed has been applied to the stereoselective synthesis of complex structural types including mesembrine and the aspidosperma alkaloids from simple precursors.3 We have described the application of this methodology to the construction of the tetracyclic core of the manzamine alkaloids, in which the single stereocenter on the unsaturated eight-membered ring template 2 dictates all of the requisite stereochemical relationships embodied in 3, which represents the tetracyclic core of manzamine A.4 Outlined herein is the extension of these preliminary investigations to the first total synthesis of manzamine A.
Assessing the vulnerability of buildings

Purpose – The purpose of this paper is to set forth a rigorous methodology for building owners and managers to conduct a vulnerability assessment of their facilities. Such a process would facilitate the use of remediation measures to limit the loss of life and property during a disaster, whether natural or man‐made.Design/methodology/approach – The author sets forth nine criteria to conduct a vulnerability assessment, along with a six‐point rating system. The criteria selected are: the level of visibility, the criticality of the site to the jurisdiction in which it is located, the impact of the site outside of the jurisdiction in which it is located, access to the site, size hazards, building height, type of construction, site population capacity, and the potential for collateral mass casualties. This evaluative process leads to five site vulnerability ratings, ranked as follows: negligible, low, medium, high, and critical.Findings – Property owners and building managers can use this process to assess the...
Highly stereoselective anti-Markovnikov hydrothiolation of alkynes and electron-deficient alkenes by a supported Cu-NHC complex

A practical, efficient, and low-cost heterogeneous catalyst consisting of a Cu-NHC (N-heterocyclic carbene) complex grafted to SBA-15 silica for the catalytic hydrothiolation of alkynes and electron-deficient alkenes under mild reaction conditions has been developed. The heterogeneous catalyst displays higher activity and stereoselectivity to Z-anti-Markovnikov isomers compared with the homogeneous analog under otherwise identical reaction conditions. The catalytic system is applicable to a broad range of alkynes and thiols and is recyclable without significant loss in catalytic performance. High activity and perfect selectivity to alkyl sulfides formed by the addition of electron-deficient alkenes to various thiols catalyzed by the supported Cu-NHC complex were also realized.
The Frobenius Problem, Rational Polytopes, and Fourier–Dedekind Sums

We study the number of lattice points in integer dilates of the rational polytope P={(x1,…,xn)∈R⩾0n:∑k=1nxkak⩽1}, where a1,…,an are positive integers. This polytope is closely related to the linear Diophantine problem of Frobenius: given relatively prime positive integers a1,…,an, find the largest value of t (the Frobenius number) such that m1a1+···+mnan=t has no solution in positive integers m1,…,mn. This is equivalent to the problem of finding the largest dilate tP such that the facet {∑k=1nxkak=t} contains no lattice point. We present two methods for computing the Ehrhart quasipolynomials L(P,t)≔#(tP∩Zn) and L(P°,t)≔#(tP°∩Zn). Within the computations a Dedekind-like finite Fourier sum appears. We obtain a reciprocity law for these sums, generalizing a theorem of Gessel. As a corollary of our formulas, we rederive the reciprocity law for Zagier's higher-dimensional Dedekind sums. Finally, we find bounds for the Fourier–Dedekind sums and use them to give new bounds for the Frobenius number.
Solution phase parallel synthesis of 1,2-phenethyldiamines

A versatile solution phase synthesis for the preparation of 1,2-phenethyldiamines has been developed for the purpose of producing lead generation libraries. A facile strategy for the parallel purification of products provides high purity products suitable for SAR evaluation in high-throughput screening assays.
Idiosyncrasies of Scalp Melanoma

Objectives/Hypothesis: Examine the accuracy of sentinel lymph node biopsy (SNB) in scalp melanoma (SM), patterns of nodal metastases, patient outcomes, and the utility of immunohistochemistry (IHC) in SNB evaluation. Study Design: Retrospective. Methods: There were 22 patients, 4 females and 18 males. Sentinel lymph nodes (SLN) were localized via preoperative lymphoscintigraphy, intraoperative gamma probe, and Lymphazurin injection. SLNs were stained with hematoxylin-eosin, S-100, HMB-45, Melan-A, micropthalmia transcription factor, and tyrosinase. SLNs were grouped into cervical (levels 1–5) and extracervical (parotid, suboccipital, retroauricular) regions. Results: There were 13 posterior and 9 anterior SMs. The first SNB were mapped to the extracervical regions in 77% of posterior and 78% of anterior lesions. SLN number ranged from 1 to 5. Ten patients had positive SLNs (PSLN). Forty percent of the PSLN group had SLNs mapped in both cervical and extracervical sites. Six underwent completion lymphadenectomy, with no additional positive nodes identified. No significant difference between PSLN and negative sentinel node (NSLN) patients was seen when compared by SLN number, Breslow's thickness, tumor ulceration, and clinical outcomes. Mean follow-up was 35 months. One patient died of disease. One isolated regional recurrence occurred. Sixty percent of PSLN and 92% of NSLN patients were recurrence free at last follow-up. One distant metastasis occurred in the NSLN group, and one local, one regional, and two patients with distant metastases were in the PSLN group at the time of last follow-up. Additional IHC did not detect other metastases in the NSLN group. Conclusions: SM is aggressive, as demonstrated by the high rate of SLN metastases, and there were no significant histopathologic factors in the primary tumor that predicted the presence of SLN metastases. SNB was accurate. The majority of first SLNs were localized in extracervical basins.
Anisotropic intrinsic spin Hall effect in quantum wires

We use numerical simulations to investigate the spin Hall effect in quantum wires in the presence of both Rashba and Dresselhaus spin–orbit coupling. We find that the intrinsic spin Hall effect is highly anisotropic with respect to the orientation of the wire, and that the nature of this anisotropy depends strongly on the electron density and the relative strengths of the Rashba and Dresselhaus spin–orbit couplings. In particular, at low densities, when only one subband of the quantum wire is occupied, the spin Hall effect is strongest for electron momentum along the [] axis, which is the opposite of what is expected for the purely 2D case. In addition, when more than one subband is occupied, the strength and anisotropy of the spin Hall effect can vary greatly over relatively small changes in electron density, which makes it difficult to predict which wire orientation will maximize the strength of the spin Hall effect. These results help to illuminate the role of quantum confinement in spin–orbit-coupled systems, and can serve as a guide for future experimental work on the use of quantum wires for spin-Hall-based spintronic applications.
Distortion and charge density wave in the Ga square net coupled to the site occupancy wave in YCo0.88Ga3Ge.

YCo0.88Ga3Ge has an incommensurately modulated structure that was solved with (3 + 1)D superspace techniques. YCo0.88Ga3Ge crystallizes in the orthorhombic superspace group Immm(α00)00s with unit cell constants of a = 4.1639(4), b = 4.1639(4), c = 23.541(2) A and a modulation vector of q = 0.3200(4)a* at 293 K. The incommensurate modulation, which creates a very large supercell (∼25 fold), arises from a charge density wave (CDW) in the square net of Ga atoms that is coupled with a site occupancy wave (SOW) of Co atoms. The distorted Ga net features polygallide ribbons, chains, as well as single atoms. Temperature dependent crystallographic studies of the structure from 100−500 K indicate that the CDW is “locked in”. Electrical conductivity and thermopower measurements in the temperature range of 300−500 K show that YCo0.88Ga3Ge is a poor metal.
Frequencies of Occultations of Stars by Planets, Satellites, and Asteroids

Calculations show that several occultations of stars by the large satellites of the outer planets, Pluto, and the large asteroids could be observed each decade with existing equipment at Earth-based telescopes. A systematic program of occultation predictions and observations is urged in order to improve our knowledge about the atmospheres, sizes, shapes, topography, and positions of these poorly understood bodies, in support of forthcoming spacecraft missions to the outer solar system.
Projectors, shadows, and conformal blocks

We introduce a method for computing conformal blocks of operators in arbitrary Lorentz representations in any spacetime dimension, making it possible to apply bootstrap techniques to operators with spin. The key idea is to implement the “shadow formalism” of Ferrara, Gatto, Grillo, and Parisi in a setting where conformal invariance is manifest. Conformal blocks in d-dimensions can be expressed as integrals over the projective null-cone in the “embedding space” $ \mathbb{R} $ d+1,1. Taking care with their analytic structure, these integrals can be evaluated in great generality, reducing the computation of conformal blocks to a bookkeeping exercise. To facilitate calculations in four-dimensional CFTs, we introduce techniques for writing down conformally-invariant correlators using auxiliary twistor variables, and demonstrate their use in some simple examples.
Liquid sheet radiator

A new external flow radiator concept, the liquid sheet radiator (LSR), is introduced. The LSR sheet flow is described and an expression for the length/width (l/w), ratio is presented. A linear dependence of l/w on velocity is predicted that agrees with experimental results. Specific power for the LSR is calculated and is found to be nearly the same as the specific power of a liquid droplet radiator, (LDR). Several sheet thicknesses and widths were experimentally investigated. In no case was the flow found to be unstable.
Organizational capital, technology adoption and the productivity slowdown

Abstract There is evidence linking the productivity slowdown of the 1970s and 1980s to changing patterns of technological adoption related to the spread of information technology (IT). Notably, IT appears to require plant-level reorganization for its full implementation. I develop a general equilibrium model in which organizational capital plays a central role in establishment dynamics, and study its transition path after a shock in the form of an incompatibility between new technologies and previously accumulated plant-level expertise. The behavior of the model is consistent with the structure of the slowdown, as well as the subsequent resurgence. Further applications are discussed.
Synthesis of quinone monoketals by diol exchange

Abstract A new procedure for the synthesis of quinone monoketals derived from a variety of diols has been developed involving treatment of the readily available dimethyl ketals with diols and BF 3 ·etherate in DME.
Generalized Cornfield conditions for the risk difference

A central question in causal inference with observational studies is the sensitivity of conclusions to unmeasured confounding. The classical Cornfield condition allows us to assess whether an unmeasured binary confounder can explain away the observed relative risk of the exposure on the outcome. It states that for an unmeasured confounder to explain away an observed relative risk, the association between the unmeasured confounder and the exposure and the association between the unmeasured confounder and the outcome must both be larger than the observed relative risk. In this paper, we extend the classical Cornfield condition in three directions. First, we consider analogous conditions for the risk difference and allow for a categorical, not just a binary, unmeasured confounder. Second, we provide more stringent thresholds that the maximum of the above-mentioned associations must satisfy, rather than weaker conditions that both must satisfy. Third, we show that all the earlier results on Cornfield conditions hold under weaker assumptions than previously used. We illustrate the potential applications by real examples, where our new conditions give more information than the classical ones.
The minimum stellar metallicity observable in the Galaxy

The first stars fundamentally transformed the early Universe through their production of energetic radiation and the first heavy chemical elements. The impact on cosmic evolution sensitively depends on their initial mass function (IMF), which can be empirically constrained through the detailed studies of ancient, metal-poor halo stars in our Galaxy. We compare the lowest magnesium and iron abundances measured in Galactic halo stars with theoretical predictions for the minimum stellar enrichment provided by Population III stars under the assumption of a top-heavy IMF. To demonstrate that abundances measured in metal-poor stars reflect the chemical conditions at their formation, and that they can thus be used to derive constraints on the primordial IMF, we carry out a detailed kinematic analysis of a large sample of metal-poor stars drawn from the Sloan Digital Sky Survey. We assess whether interstellar accretion has altered their surface abundances. We find that the accretion is generally negligible, even at the extremely low levels where the primordial IMF can be tested. We conclude that the majority of the first stars were very massive, but had likely masses below ∼140 M� .
TMACS: type-based distributed middleware for mobile ad-hoc networks

This paper presents the design and implementation of TMACS -- a distributed middleware framework for Mobile Ad-hoc Network (MANETs). TMACS leverages type-based group communication paradigm in which type is used as a first-class abstraction for identifying groups and provides a novel group-based RPC-mechanism called TRPC as a higher-level communication abstraction suitable for MANET computing environments. A fully decentralized discovery service has been provided to lookup the meta-information of the distributed objects and services. At the network layer, TMACS implements TypeCast routing protocol to efficiently support TRPC and service discovery via effective type dissemination and aggregation mechanisms. A complete system implementation of TMACS has been deployed on linux-based mobile devices and has been used to program a variety of applications. We present results from a selected set of applications and services that include an ad-hoc distributed caching service and an ad-hoc marketplace application. The physical implementations were used to evaluate the performance of TMACS and demonstrate its resiliency in the presence of mobility-induced topology changes.
Cosmology of the tachyon in brane inflation

In certain implementations of the brane inflationary paradigm, the exit from inflation occurs when the branes annihilate through tachyon condensation. We investigate various cosmological effects produced by this tachyonic era. We find that only a very small region of the parameter space (corresponding to slow roll with tiny inflaton mass) allows for the tachyon to contribute some e-folds to inflation. In addition, non-adiabatic density perturbations are generated at the end of inflation. When the brane is moving relativistically this contribution can be of the same order as fluctuations produced 55 e-folds before the end of inflation. The additional contribution is exactly scale invariant and enhances the tensor/scalar ratio. Additional non-Gaussianities will also be generated, sharpening current constraints on Dirac–Born–Infeld-type models which already predict a significantly non-Gaussian signal.
High-energy inverse free-electron-laser accelerator.

We study the inverse free-electron-laser (IFEL) accelerator and show that it can accelerate electrons to the few hundred GeV region with average acceleration rates of the order of 200 MeV/m. Several possible accelerating structures are analyzed, and the effect of synchrotron-radiation losses is studied. The longitudinal phase stability of accelerated particles is also analyzed. A Hamiltonian description, which takes into account the dissipative features of the IFEL accelerator, is introduced to study perturbations from the resonant acceleration. Adiabatic invariants are obtained and used to estimate the change of the electron phase-space density during the acceleration process.
Quantum computing and a unified approach to fast unitary transforms

A quantum computer directly manipulates information stored in the state of quantum mechanical systems. The available operations have many attractive features but also underly severe restrictions, which complicate the design of quantum algorithms. We present a divide-and-conquer approach to the design of various quantum algorithms. The class of algorithm includes many transforms which are well-known in classical signal processing applications. We show how fast quantum algorithms can be derived for the discrete Fourier transform, the Walsh-Hadamard transform, the Slant transform, and the Hartley transform. All these algorithms use at most O(log2 N) operations to transform a state vector of a quantum computer of length N.© (2002) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Optimal Depreciation Schedules for Regulated Utilities

This paper+ derives the combined effect of depreciation schedules and regulatory lag on a firm's choice of input mix. It shows that a schedule called the real constant (RC) schedule induces efficient capital-labor proportions. More (less) accelerated schedules cause undercapitalization (overcapitalization). Since most typically used schedules are accelerated relative to the RC schedule, they lead to undercapitalization. Testable predictions are derived by showing that these distortions become more severe as the inflation rate increases and as the lag length decreases.
Microwave measurements on a well-collimated dusty plasma sheet for communications blackout applications

Vehicles traveling at hypersonic velocities within the Earth's atmosphere, such as spacecraft during reentry and weapons systems, are enveloped by a dense plasma layer. This plasma layer reflects and significantly attenuates GPS and S-band signals for vehicle navigation, telemetry, and voice communications, resulting in radio blackout. In these studies, a linear hollow cathode produces an electron beam that is accelerated into a low pressure (50 to 150 mTorr) background of Argon gas, producing an electron beam discharge. A relatively constant 170 Gauss axial magnetic field is produced by two electromagnet coils arranged in a Helmholtz configuration. This results in a well-collimated electron beam, producing a 2-dimensional Argon plasma discharge in a sheet configuration. This discharge sheet is approximately 40 cm long by 30 cm wide by 1 cm thick, and can produce electron densities as high as 1012 cm−3. The plasma sheet is intended to mimic the intense plasma layer produced and experienced by vehicles traveling at hypersonic velocities. The electron beam is accelerated vertically towards a grounded beam dump electrode. This electrode is modified to include an array of six piezo buzzers modified and filled with alumina powder. When supplied with a modest voltage, the piezoelectric shakers uniformly drop dust particles into the plasma sheet discharge directly below at a constant rate, creating a dusty plasma. A transmitting microwave horn is oriented normal to the dense plasma sheet while the receiving horn is mounted on a stage that can be rotated up to 180 degrees azimuthally. Microwave cutoff, transmission, reflection, and scattering measurements of the plasma sheet are made in the S-band and X-band range. These measurements are relevant for applications related to communications blackout and over-the-horizon communications.
Parity and the spin—statistics connection

A simple demonstration of the spin—statistics connection for general causal fields is obtained by using the parity operation to exchange spatial coordinates in the scalar product of a locally commuting field operator, evaluated at position x, with the same field operator evaluated at − x, at equal times.
A Black Woman as Rhetorical Critic: Validating Self and Violating the Space of Otherness

This essay explores a Black woman rhetorical critic's search to re-cover Black women's rhetorical traditions in America, which centers Black women's epistemology in a rhetoric of survival. A Black ...
Lithium-doped radiation resistant silicon solar cells

It is well known that impurities in silicon interact with radiation-induced vacancies to produce complexes which are stable at room temperature. For example, there are the vacancy-oxygen and vacancy-phosphorus centers produced in n-type silicon by electron irradiation. These centers modify the electrical properties of the material, primarily by decreasing the minority-carrier lifetime. Consequently, when devices such as solar cells are irradiated, the characteristics of the device are severely degraded. This talk will present evidence that when lithium is used as the dominant impurity in silicon, the production of recombination centers is reduced. This results in solar cells with an improved radiation resistance. This study has been performed on solar cells with the diffused p on n-type base configuration. It was found that under certain conditions the use of lithium in the above cell has led to a radiation resistance to 1 MeV electrons superior to even standard n-on-p solar cells, heretofore, the most radiations-resistant cell.
Seeking Truth after 50 Years: The National Committee for Investigation of the Truth about the Jeju 4.3 Events

Between 1948 and 1954, a communist-led uprising in Jeju, South Korea, and the subsequent counterinsurgency campaign by the new anticommunist government resulted in an estimated 15,000 deaths. The massacres were systematically hidden from the general public and the victims' demands for truth and justice were totally suppressed during consecutive anticommunist military regimes for some 50 years. However, with democratization in 1987, a movement was started by local students, activists and journalists to find the truth about civilian massacres. After a long and painstaking journey, the first South Korean truth commission was established in 2000 to investigate the massacres and restore the dignity of victims and their family members. The advocacy movement process and the truth commission itself have gone largely unnoticed by scholars and practitioners around the world. Based on interviews and archival research, this article provides the first close examination of the South Korean transitional justice movement.
Synthesis for logical initializability of synchronous finite-state machines

Logical initializability is the property of a gate-level circuit whereby it can be driven to a unique start state when simulated by a three-valued (0, 1, X) simulator. In practice, commercial logic and fault simulators often require initialization under such a three-valued simulation model. In this paper, the first sound and systematic synthesis method is proposed to ensure the logical initializability of synchronous finite-state machines. The method includes both state assignment and combinational logic synthesis steps. It is shown that a previous approach to synthesis-for-initializability, which uses a constrained state assignment method, may produce uninitializable circuits. Here, a new state assignment method is proposed that is guaranteed correct. Furthermore, it is shown that combinational logic synthesis also has a direct impact on initializability; necessary and sufficient constraints on combinational logic synthesis are proposed to guarantee that the resulting gate-level circuits are logically initializable. The above two synthesis steps have been incorporated into a computer-aided design tool, SALSIFY, targeted to both two-level and multilevel implementations.
Concepts learning with fuzzy clustering and relevance feedback

Abstract In recent years feedback approaches have been used in relating low-level image features with concepts to overcome the subjective nature of the human image interpretation. Generally, in these systems when the user starts with a new query, the entire prior experience of the system is lost. In this paper, we address the problem of incorporating prior experience of the retrieval system to improve the performance on future queries. We propose a semi-supervised fuzzy clustering method to learn class distribution (meta knowledge) in the sense of high-level concepts from retrieval experience. Using fuzzy rules, we incorporate the meta knowledge into a probabilistic feature relevance feedback approach to improve the retrieval performance. Results on synthetic and real databases show that our approach provides better retrieval precision compared to the case when no retrieval experience is used.
Observation of the Highest Coordination Number in Planar Species: Decacoordinated Ta©B10− and Nb©B10− Anions

TaB10- and NbB10- clusters are produced in a laser-vaporization supersonic molecular beam cluster source and characterized by photoelectron spectroscopy.
High-Power-Density Superconducting Generator

The application of superconductors to the field windings of synchronous ac generators has been the subject of considerable development effort over the past decade. Machines and/or components have been built and tested in more than half a dozen countries. This paper considers an airborne high-power-density superconducting generator under construction at the authors' company. The unique requirements of this application include high power density, fast startup capability, and high terminal voltage. As a consequence, the design approach is quite different from that of any other generator. The significant design constraints and the configuration of the generator under construction are reviewed.
Fast Query Processing by Distributing an Index over CPU Caches

Data intensive applications on clusters often require requests quickly be sent to the node managing the desired data. In many applications, one must look through a sorted tree structure to determine the responsible node for accessing or storing the data. Examples include object tracking in sensor networks, packet routing over the Internet, request processing in publish-subscribe middleware, and query processing in database systems. When the tree structure is larger than the CPU cache, the standard implementation potentially incurs many cache misses for each lookup; one cache miss at each successive level of the tree. As the CPU-RAM gap grows, this performance degradation will only become worse in the future. We propose a solution that takes advantage of the growing speed of local area networks for clusters. We split the sorted tree structure among the nodes of the cluster. We assume that the structure will fit inside the aggregation of the CPU caches of the entire cluster. We then send a word over the network (as part of a larger packet containing other words) in order to examine the tree structure in another node's CPU cache. We show that this is often faster than the standard solution, which locally incurs multiple cache misses while accessing each successive level of the tree. The principle is demonstrated with a cluster configured with Pentium III nodes connected with a Myrinet network. The new approach is shown to be 50% faster on this current cluster. In the future, the new approach is expected to have a still greater advantage as networks grow in speed, and as cache lines grow in length (greater cache miss penalty). This can be used to successfully overcome the inherent memory latency associated with cache misses
Nickel-BINAP Catalyzed Enantioselective α-Arylation of α-Substituted γ-Butyrolactones

A Ni(0)−BINAP system is utilized for the highly enantioselective α-arylation of α-substituted γ-butyrolactones with aryl chlorides and bromides. α-Quaternization is achieved in moderate to excellent yields. Furthermore, the rate accelerating effect caused by the addition of Zn(II) salts is investigated.
Plurisubharmonic Defining Functions, Good Vector Fields, and Exactness of a Certain One Form

We show that the approaches to global regularity of the -Neumann problem via the methods listed in the title are equivalent when the conditions involved are suitably modified. These modified conditions are also equivalent to one that is relevant in the context of Stein neighborhood bases and Mergelyan type approximation.
Turret Mooring Design Based on Analytical Expressions of Catastrophes of Slow-Motion Dynamics

Analytical expressions of the bifurcation boundaries exhibited by turret mooring systems (TMS), and expressions that define the morphogeneses occurring across boundaries are developed. These expressions provide the necessary means for evaluating the stability of a TMS around an equilibrium position, and constructing catastrophe sets in two or three-dimensional parametric design spaces. Sensitivity analyses of the bifurcation boundaries define the effect of any parameter or group of parameters on the dynamical behavior of the system. These expressions allow the designer to select appropriate values for TMS design parameters without resorting to trial and error. A four-line TMS is used to demonstrate this design methodology. The mathematical model consists of the nonlinear, fifth-order, low-speed, large-drift maneuvering equations. Mooring lines are modeled with submerged catenaries, and include nonlinear drag. External excitation consists of time-independent current, wind, and mean wave drift.
Spin axes and shape models of asteroid pairs: Fingerprints of YORP and a path to the density of rubble piles

Abstract An asteroid pair consists of two unbound objects with almost identical heliocentric orbital elements that were formed when a single “rubble pile” asteroid failed to remain bound against an increasing rotation rate. Models suggest that the pairs’ progenitors gained the fast rotation due to the YORP effect. Since it was shown that the spin axis vector can be aligned by the YORP effect, such a behavior should be seen on asteroid pairs, if they were indeed formed by the described mechanism. Alternatively, if the pairs were formed by a collision, the spin axes should have a random direction and small or young bodies might have a tumbling rotation. Here I apply the lightcurve inversion method on self-obtained photometric data, in order to derive the rotation axis vectors and shape models of the asteroid pairs 2110, 3749, 5026, 6070, 7343 and 44612. Three asteroids resulted with polar-directed spin axes and three objects with ambiguous results. In addition, the secondary member 44612 presents the same sense of rotation as its primary member 2110, and its spin is not tumbling. Finally, I use a rotational fission model, based on the assumption of an angular momentum conservation, and match it to the measured spin, shape, and mass ratio parameters in order to constrain the density of the primary members in the pairs. Using this method, low density values that are expected from a “rubble pile” are derived. All these results lead to the conclusion that the disruption of these asteroid pairs was most likely the outcome of the YORP effect that spun-up “rubble pile” asteroids.
The expression of native and cultured human retinal pigment epithelial cells grown in different culture conditions.

Aim: To determine the transcriptional proximity of retinal pigment epithelium (RPE) cells grown under different culture conditions and native RPE. Methods: ARPE-19 cells were grown under five conditions in 10% CO2: “subconfluent” in DMEM/F12 + 10% FBS, “confluent” in serum and serum withdrawn, and “differentiated” for 2.5 months in serum and serum withdrawn medium. Native RPE was laser microdissected. Total RNA was extracted, reverse transcribed, and radiolabelled probes were hybridised to an array containing 5353 genes. Arrays were evaluated by hierarchical cluster analysis and significance analysis of microarrays. Results: 78% of genes were expressed by native RPE while 45.3–47.7% were expressed by ARPE-19 cells, depending on culture condition. While the most abundant genes were expressed by native and cultured cells, significant differences in low abundance genes were seen. Hierarchical cluster analysis showed that confluent and differentiated, serum withdrawn cultures clustered closest to native RPE, and that serum segregated cultured cells from native RPE. The number of differentially expressed genes and their function, and profile of expressed and unexpressed genes, demonstrate differences between native and cultured cells. Conclusions: While ARPE-19 cells have significant value for studying RPE behaviour, investigators must be aware of how culture conditions can influence the mRNA phenotype of the cell.
ATMOSPHERIC COMPOSITION OF WEAK G BAND STARS: CNO AND Li ABUNDANCES

We determined the chemical composition of a large sample of weak G band stars—a rare class of G and K giants of intermediate mass with unusual abundances of C, N, and Li. We have observed 24 weak G band stars with the 2.7 m Harlan J. Smith Telescope at the McDonald Observatory and derived spectroscopic abundances for C, N, O, and Li, as well as for selected elements from Na-Eu. The results show that the atmospheres of weak G band stars are highly contaminated with CN-cycle products. The C underabundance is about a factor of 20 larger than for normal giants and the 12C/13C ratio approaches the CN-cycle equilibrium value. In addition to the striking CN-cycle signature the strong N overabundance may indicate the presence of partially ON-cycled material in the atmospheres of the weak G band stars. The exact mechanism responsible for the transport of the elements to the surface has yet to be identified but could be induced by rapid rotation of the main sequence progenitors of the stars. The unusually high Li abundances in some of the stars are an indicator for Li production by the Cameron-Fowler mechanism. A quantitative prediction of a weak G band star's Li abundance is complicated by the strong temperature sensitivity of the mechanism and its participants. In addition to the unusual abundances of CN-cycle elements and Li, we find an overabundance of Na that is in accordance with the NeNa chain running in parallel with the CN cycle. Apart from these peculiarities, the element abundances in a weak G band star's atmosphere are consistent with those of normal giants.