cssi/SciSciGPT-SciSciNet huggingface dataset:
Fault-Tolerant Geometric Spanners

We present two new results about vertex and edge fault-tolerant spanners in Euclidean spaces.We describe the first construction of vertex and edge fault-tolerant spanners having optimal bounds for maximum degree and total cost. We present a greedy algorithm that for any t > 1 and any non-negative integer k, constructs a k-fault-tolerant t-spanner in which every vertex is of degree O(k) and whose total cost is O(k2) times the cost of the minimum spanning tree; these bounds are asymptotically optimal.Our next contribution is an efficient algorithm for constructing good fault-tolerant spanners. We present a new, sufficient condition for a graph to be a k-fault-tolerant spanner. Using this condition, we design an efficient algorithm that finds fault-tolerant spanners with asymptotically optimal bound for the maximum degree and almost optimal bound for the total cost.
Who's viewed you?: the impact of feedback in a mobile location-sharing application

Feedback is viewed as an essential element of ubiquitous computing systems in the HCI literature for helping people manage their privacy. However, the success of online social networks and existing commercial systems for mobile location sharing which do not incorporate feedback would seem to call the importance of feedback into question. We investigated this issue in the context of a mobile location sharing system. Specifically, we report on the findings of a field de-ployment of Locyoution, a mobile location sharing system. In our study of 56 users, one group was given feedback in the form of a history of location requests, and a second group was given no feedback at all. Our major contribution has been to show that feedback is an important contributing factor towards improving user comfort levels and allaying privacy concerns. Participants' privacy concerns were reduced after using the mobile location sharing system. Additionally,our study suggests that peer opinion and technical savviness contribute most to whether or not participants thought they would continue to use a mobile location technology.
Specularly vs Diffusely Reflecting Walls for Cavity-Type Sources of Radiant Energy

Although the theory of partially enclosed, cavity-type sources of radiant energy, with a few clarifications and corrections, has reached an apparent fruition, surface characteristics and practical construction problems will still limit the closeness to which these sources can he made to approach blackbodies. This paper gives results, which agree with prior published data, of a new computation for cylinders and shows the ray-trace analysis of cones to be unacceptable.
Sonos Nonvolatile Memory Cell Programming Characteristics

Silicon-oxide-nitride-oxide-silicon (SONOS) nonvolatile memory is gaining favor over conventional EEPROM FLASH memory technology. This paper characterizes the SONOS write operation using a nonquasi-static MOSFET model. This includes floating gate charge and voltage characteristics as well as tunneling current, voltage threshold and drain current characterization.
Aided strapdown inertial navigation for autonomous underwater vehicles

This paper presents a navigation algorithm based on aided strapdown inertial navigation (INS) for an underwater autonomous underwater vehicle (AUV). The AUV is equipped with a long baseline (LBL) acoustic positioning system, acoustic Doppler current profiler (ADCP) and a depth sensor to aid the INS. They have, however, much slower data rates than that of the INS. A linearized, quaternion-based dynamic model and measurement model of the INS output errors are presented. Data from different sensors are fused by applying the extended Kalman filer (EKF) to estimate and correct the errors. Due to the difficulty of generating realistic simulation scenario, real data (raw INS measurement) collected from AUV field experiments are processed to test the algorithm. Without knowing the ground truth, however, performance evaluation becomes much more complicated and needs further research. In this paper, the problem is circumvented by considering the post-processed real data as the "ground truth" and noisy raw measurements are generated from this "ground truth" to feed the algorithm. The simulation results demonstrate the algorithm applicability and show that by incorporating readings from the ADCP and the depth sensor, the (horizontal) position errors still increase but with a significant lower rate than the case of stand-alone operation. If the LBL sensor is further included, the navigation errors can be constrained within a certain bound.
Discourse as an Interactional Achievement III: The Omnirelevance of Action

(1995). Discourse as an Interactional Achievement III: The Omnirelevance of Action. Research on Language and Social Interaction: Vol. 28, No. 3, pp. 185-211.
Classical Theory of Spin Configurations in the Cubic Spinel

It is shown that the Yafet-Kittel triangular spin-configurations in the cubic spinel do not minimize the classical Heisenberg exchange energy. (Only nearest-neighbor $A\ensuremath{-}B$ and $B\ensuremath{-}B$ interactions, ${J}_{\mathrm{AB}}$ and ${J}_{\mathrm{BB}}$, are included; one spin-magnitude ${S}_{A}$ for the $A$ sites, and one, ${S}_{B}$, for the $B$ sites is assumed.) A theory of the classical ground state more general than that of Yafet and Kittel is investigated. This consists of first determining the largest value, ${y}_{0}$, of $y\ensuremath{\equiv}\frac{{J}_{\mathrm{BB}}{S}_{B}}{{J}_{\mathrm{AB}}{S}_{A}}$ for which the N\'eel configuration is stable with respect to arbitrary small spin-deviations. (${y}_{0}$ is roughly 10% smaller than the value of $y$ found by Yafet and Kittel for the breakdown of the N\'eel configuration.) A perturbation method for finding the minimum energy configuration when $y\ensuremath{-}{y}_{0}$ is small and positive is then employed. It is concluded, (1) that equilibrium configurations exist which have nonzero angles between spins on the $A$ sites simultaneously with angles between those on the $B$ sites, in contrast with the Yafet-Kittel results; and (2) that there will be long-range-ordered, canted spin configurations in the cubic spinel, contrary to Anderson's suggestion. These conclusions are discussed in connection with experiments on Mn${\mathrm{Cr}}_{2}$${\mathrm{O}}_{4}$ and ${\mathrm{Mn}}_{3}$${\mathrm{O}}_{4}$.
Development of technologies for imaging sensor testing at AEDC

Arnold Engineering Development Center (AEDC) is involved in the development of technologies that enable hardwarein- the-loop (HWIL) testing with high-fidelity complex scene projection to validate sensor mission performance. Radiometric calibration with National Institute of Science and Technology (NIST) radiometers has improved radiometric and temporal fidelity testing in this cold background environment. This paper provides an overview of pertinent technologies being investigated and implemented at AEDC to support a variety of program needs such as HWIIL testing and space situational awareness (SSA).
Terahertz emission via ultrashort pulse excitation of magnetic metal surfaces

Terahertz emission from a single crystal iron film is studied. The terahertz emission results from optical rectification of an ultrashort optical pulse due to the magnetic and surface contributions to the second order nonlinearity
Arthroscopic dorsal wrist ganglion excision with color-aided visualization of the stalk: minimum 1-year follow-up

Background Dorsal wrist ganglia (DWG) are a common, benign soft-tissue mass of the wrist. Excision of DWG is a common procedure performed by hand surgeons and may be performed using either open or arthroscopic techniques. This study aims to evaluate the frequency of stalk visualization with intralesional injection of inert dye in the course of arthroscopic excision along with incidence of recurrence with a minimum of 1-year follow-up.
Ultraviolet-Optical Double-Resonance study of the predissociated C̃′ 1Ag state of acetylene

Abstract Ultraviolet-Optical Double-Resonance (UVODR) spectra were recorded via individually selected rotation-vibration intermediate levels in the A 1 A u state of acetylene. These spectra reveal a previously unobserved predissociated electronic state, the π ∗ (a g ) 2 ← π(a u ) 2 doubly excited C ′ 1 A g state. Owing to the changes in the HCC bond angle from 120° to 103°, and in the CC bond-order from 2 in the A 1 A u state to 1 in the C ′ 1 A g state, long progressions in the CC stretch (ν2) and the trans-bending (ν3) vibrations and their combinations are observed. Although the C ′ 1 A g state is predissociated, the rotational simplification provided by UVODR permits complete resolution of rotational structure in the lowest energy vibrational level. The principal observations for the HCCH and DCCD isotopomers include: T0 = 62 294(4) and 62 237(2) cm−1, ν2 = 884(10) and 822(10) cm−1, ν3 = 1303(20) and 935(10) cm−1, A = 7.90(7) and 4.65(5) cm−1, B = 0.880(7) and 0.773(5) cm−1, C = 0.792(7) and 0.641(5) cm−1, respectively. From the rotational constants the geometry of this 1Ag state is deduced to be r CC = 1.65(2) A , r CH = 1.14(3) A , and θHCC = 103(4)°.
Reasoning about arrays

The use of complete and precise assertions, developed by Floyd and Hoare, is a powerful method for avoiding programming errors. For nontrivial programs, however, such assertions become extremely tedious when written in first-order predicate calculus.In the case of array-manipulating programs, this tedium can be alleviated by several notational and conceptual devices: (1) partition diagrams, which relate intervals of subscript values; (2) pointwise extension, which reduces the need for explicit quantification; and (3) a hierarchy of useful equivalence relations among array values.The effectiveness of these ideas is illustrated by programs for binary search and for merging.
Ensemble Subsampling for Imbalanced Multivariate Two-Sample Tests

Some existing nonparametric two-sample tests for equality of multivariate distributions perform unsatisfactorily when the two sample sizes are unbalanced. In particular, the power of these tests tends to diminish with increasingly unbalanced sample sizes. In this article, we propose a new testing procedure to solve this problem. The proposed test, based on the nearest neighbor method by Schilling, employs a novel ensemble subsampling scheme to remedy this issue. More specifically, the test statistic is a weighted average of a collection of statistics, each associated with a randomly selected subsample of the data. We derive the asymptotic distribution of the test statistic under the null hypothesis and show that the new test is consistent against all alternatives when the ratio of the sample sizes either goes to a finite limit or tends to infinity. Via simulated data examples we demonstrate that the new test has increasing power with increasing sample size ratio when the size of the smaller sample is fixe...
Supersymmetric rings in field theory

We study the dynamics of BPS string-like objects obtained by lifting monopole and dyon solutions of N = 2 Super-Yang-Mills theory to five dimensions. We present exact traveling wave solutions which preserve half of the supersymmetries. Upon compactification this leads to macroscopic BPS rings in four dimensions in field theory. Due to the fact that the strings effectively move in six dimensions the same procedure can also be used to obtain rings in five dimensions by using the hidden dimension.
Stability and Three-Dimensional Aromaticity of closo-NBn-1Hn Azaboranes, n = 5−12

Computations on all the possible positional isomers of the closo-azaboranes NB(n)()(-)(1)H(n)() (n = 5-12) reveal substantial differences in the relative energies. Data at the B3LYP/6-311+G level of density functional theory (DFT) agree well with expectations based on the topological charge stabilization, with the qualitative connectivity preferences of Williams, and with the Jemmis-Schleyer six interstitial electron rules. The energetic relationship involving each of the most stable positional isomers, 1-NB(4)H(5), NB(5)H(6), 2-NB(6)H(7), 1-NB(7)H(8), 4-NB(8)H(9), 1-NB(9)H(10), 2-NB(10)H(11), NB(11)H(12), was based on the energies (DeltaH) of the model reaction: NBH(2) + (n-1)BH(increment) --> NB(n)()H(n)()(+1) (n = 4-11). This evaluation shows that the stabilities of closo-azaboranes NB(n)()(-)(1)H(n)() (n = 5-12) increase with increasing cluster size from 5 to 12 vertexes. The "three-dimensional aromaticity" of these closo-azaboranes NB(n)()(-)(1)H(n)() (n = 5-12) is demonstrated by their the nucleus-independent chemical shifts (NICS) and their magnetic susceptibilities (chi), which match one another well. However, there is no direct relationship between these magnetic properties and the relative stabilities of the positional isomers of each cluster. As expected, other energy contributions such as topological charge stabilization and connectivity can be equally important.
Inequality and the business cycle: A consumption viewpoint

Using Consumer Expenditure Survey data, we obtain summary measures of the distributions of income and consumption for each quarter between 1980 and 1994. We find that the trends in the distribution of income and consumption and the response of these trends to changes in inflation and unemployment were similar during this period. We find that unemployment does not significantly affect the inequality measures and that inflation has a progressive effect, i.e., that a decrease in inflation is associated with an increase in inequality. Finally, we find that the relationship between inequality and macroeconomic variables during the 1990s may be similar to the relationship that existed prior to 1980.
A photometric study of Saturn and its rings

A 72-in. telescope and a polarimeter of the Wollaston type with a focal-plane scanning mechanism were used in the investigations reported. On a few occasions observations were made with a 42-in. reflector. The polarization data obtained are presented as vectors superimposed on a drawing of the planet. It is concluded that in the ultraviolet and close to opposition the vectors are consistently radial and decrease to nearly zero near the center of the disk. The polarization is essentially the same at all limbs. It is pointed out that under good seeing conditions Saturn presents a consistent though somewhat complicated, photometric pattern.
Were Newspapers More Interested in Pro-Obama Letters to the Editor in 2008? Evidence From a Field Experiment:

During the 2008 presidential election, the authors submitted letters to the editor at 100 major U.S. newspapers as part of a field experiment to test whether interest in the letter depended on whic...
Olfactory Discrimination of Plant Volatiles by the European Starling

Passerine species that re-use nest sites often incorporate fresh green vegetation into their nests, a behaviour consistent with the possibility that some birds may use chemical properties of plants to counteract the selective potential of parasites and pathogens. We tested adult starlings (Sturnus vulgaris) for their physiological capacity and behavioural ability to detect and discriminate between volatiles emitted from plant material. Multi-unit electrophysiological recordings from olfactory nerves of adults indicated that strong responses were reliably elicited by volatiles from six plant species. After pairings of plant volatiles with gastro-intestinal malaise, birds exhibited conditioned avoidance in behavioural experiments, and made all possible pairwise discriminations between volatiles of the various plant species. Bilateral olfactory nerve cuts prior to conditioning abolished the ability to acquire avoidance, suggesting that olfactory cues mediated the response to plant species. These and previous results suggest that starlings use volatile cues to discriminate and choose between plants used in nest construction. The significance of fresh vegetation incorporated into a dry nest matrix has been a subject of speculation (Collias & Collias 1984). Four major hypotheses have emerged as explanations for the utility of this behaviour: birds may incorporate vegetation (1) to conceal their nest from the view of predators; (2) to regulate the humidity of the nest environment, presumably to alter the desiccation rate of the eggs; (3) to influence the heat flux dynamics of the nest and its occupants; and (4) to fumigate the nest via the chemical compounds contained therein and ameliorate the effects of parasites and pathogens against eggs or young. The degree to which any or all of these hypotheses influence the life history of passerines is largely unknown. We have been studying vegetation preferences demonstrated by the European starling, Sturnus vulgaris, and the biological activity of the plants as related to the fumigant hypothesis (Clark & Mason 1985). Briefly, we found that starlings selected fresh vegetation with high biocidal potential relative to available plants in the habitat, and that these plants possess more volatiles at higher concentrations relative to other available plants. Because volatiles were implicated as the primary biocidal agents, we hypothesized that starlings might use chemical cues as one source of information for selecting appro- priate plants during nest construction. Chemical cues would provide an excellent index for this purpose because they may be correlated with the concentration of biocides, while leaf shape or colour may not (Clark & Mason 1985). This paper reflects a partial test of the criterion that passerines are able to utilize volatile (e.g. olfactory) cues as one basis for selecting fresh plant material used during nest construction.
Oxygen Abundances in Two Metal-Poor Subgiants from the Analysis of the 6300 Å Forbidden O I Line

Recent LTE analyses (Israelian et al.; Boesgaard et al.) of the OH bands in the optical ultraviolet spectra of nearby metal-poor subdwarfs indicate that oxygen abundances are generally higher than those previously determined from the analysis of the [O I] doublet in the spectra of low-metallicity giants. On average, the difference increases with decreasing metallicity and reaches Δ[O/Fe] ~ +0.6 dex as [Fe/H] approaches -3.0. Employing high-resolution (R = 50,000), high–signal-to-noise ratio (~250) echelle spectra of the two stars found by Israelian et al. to have the highest [O/Fe] ratios, viz., BD +23°3130 and BD +37°1458, we conducted abundance analyses based on about 60 Fe I and seven–nine Fe II lines. We determined from Kurucz LTE models the appropriate values of Teff, log g, [Fe/H], and vt, as well as abundances of Na, Ni, and the traditional α-elements Mg, Si, Ca, and Ti, independent of the calibration of color versus Teff scales. We determined oxygen abundances from spectral synthesis of the stronger line (λ6300) of the [O I] doublet. The ionization equilibrium of Fe indicates that these two stars are subgiants rather than subdwarfs, and our derived values of Teff are 150–300 K lower than those assumed by the previous investigators, although the resulting [Fe/H] values differ only slightly. The syntheses of the [O I] line lead to smaller values of [O/Fe], consistent with those found earlier among halo field and globular cluster giants. We obtain [O/Fe] = +0.35 ± 0.2 for BD +23°3130 and +0.50 ± 0.2 for BD +37°1458. In the former, the [O I] line is very weak (~1 mA), so that the quoted [O/Fe] value may in reality be an upper limit. Therefore, in these two stars a discrepancy exists between the [O/Fe] ratios derived from [O I] and the OH feature, and the origin of this difference remains unclear. Until the matter is clarified, we suggest it is premature to conclude that the ab initio oxygen abundances of old, metal-poor stars need to be revised drastically upward.
Unification of Higgs and gauge fields in five dimensions

Abstract We construct realistic theories in which the Higgs fields arise from extra-dimensional components of higher-dimensional gauge fields. In particular, we present a minimal 5D SU(3)C×SU(3)W model and a unified 5D SU(6) model. In both cases the theory is reduced to the minimal supersymmetric standard model below the compactification scale, with the two Higgs doublets arising from the 5D gauge multiplet. Quarks and leptons are introduced in the bulk, giving Yukawa couplings without conflicting with higher-dimensional gauge invariance. Despite the fact that they arise from higher-dimensional gauge interactions, the sizes of these Yukawa couplings can be different from the 4D gauge couplings due to wave-function profiles of the matter zero modes determined by bulk mass parameters. All unwanted fields are made heavy by introducing appropriate matter and superpotentials on branes, which are also the source of intergenerational mixings in the low-energy Yukawa matrices. The theory can accommodate a realistic structure for the Yukawa couplings as well as small neutrino masses. Scenarios for supersymmetry breaking and the μ-term generation are also discussed.
Tandem Michael addition / enolate-accelerated cope rearrangements

Abstract The formation of fused cyclooctanes via the intramolecular addition of an unsymmetrical allylsilane to a conjugated dienone has been shown to occur via a novel tandem Michael addition / enolate-accelerated Cope rearrangement mechanism.
Local syzygies of multiplier ideals

The purpose of this note is to prove an elementary but somewhat surprising result concerning the syzygies of multiplier ideals. It follows in particular that in dimensions three or higher, multiplier ideals are very special among all integrally closed ideals. Let X be a smooth complex algebraic variety of dimension d, and let b ⊆ OX be an ideal sheaf. Given a rational or real number c > 0 one can construct the multiplier ideal
Preparation and Baeyer‐Villiger Reaction of Certain 2‐Carbalkoxycyclopropyl Methyl Ketones

Abstract Treatment of mixed anhydrides derived from cis‐ and trans ‐2‐carbobenzyloxycyclopropanecarboxylic acids and ethyl chloroformate with ethoxymagnesio di‐ tert ‐butyl malonate and subsequent treatment of the resulting adducts with p ‐toluenesulfonic acid afforded cis‐ and trans‐ benzyl 2‐acetylcyclopropanecar‐boxylates in good to excellent yields, with retention of the original stereochemistry of the systems. These methyl ketones and an open chain congener, benzyl levulinate, were inert toward m‐ chloroper‐benzoic acid. The cis‐ isomer and benzyl levulinate underwent normal Baeyer‐Villiger reactions mediated by trifluoroperacetic acid, forming moderate yields of the acetate ester insertion products.
Getting organized at the nanoscale with thermotropic liquid crystal solvents

This paper summarizes recent progress toward an emerging, unconventional application of thermotropic liquid crystals (LCs) - their use as solvents for controlling the assembly of non-LC nanoscale building blocks. LCs offer a number of potential advantages compared to conventional isotropic solvents, including the ability to influence building block orientation and other structural properties. Strategies are reviewed for the exploitation of LC media to engineer order in a range of systems, including oriented organic monolayers, chiral films, and nanometer-scale particles.
The Clustering of High-Redshift Galaxies in the Cold Dark Matter Scenario

We investigate the clustering of high-redshift galaxies in five variants of the cold dark matter (CDM) scenario, using hydrodynamic cosmological simulations that resolve the formation of systems with circular velocities vc ≥ 100 km s-1 (Ω = 1) or vc ≥ 70 km s-1 (Ω = 0.4). Although the five models differ in their cosmological parameters and in the shapes and amplitudes of their mass power spectra, they predict remarkably similar galaxy clustering at z = 2, 3, and 4. The galaxy correlation functions show almost no evolution over this redshift range, even though the mass correlation functions grow steadily in time. Despite the fairly low circular velocity threshold of the simulations, the high-redshift galaxies are usually highly biased tracers of the underlying mass distribution; the bias factor evolves with redshift and varies from model to model. Predicted correlation lengths for the resolved galaxy population are 2-3 h-1 Mpc (comoving) at z = 3. More massive galaxies tend to be more strongly clustered. These CDM models have no difficulty in explaining the strong observed clustering of Lyman-break galaxies, and some may even predict excessive clustering. Because the effects of bias obscure differences in mass clustering, it appears that Lyman-break galaxy clustering will not be a good test of cosmological models but will instead provide a tool for constraining the physics of galaxy formation.
Beautiful structures: an appreciation of the contributions of Alan Selman

Professor Alan Selman has been a giant in the field of computational complexity for the past forty years. This article is an appreciation, on the occasion of his retirement, of some of the most lovely concepts and results that Alan has contributed to the field.
Total synthesis of (+)-grindelic acid by stereocontrolled oxonium ion activated pinacol ring expansion. Chemical proof of the absolute configuration of all grindelane diterpenes

(+)-Grindelic acid, synthesized enantioselectively from the levorotatory Wieland-Miescher ketone and (−)-linalool and necessarily formulated as 1a, is shown to be antipodal to the major diterpenoid of Grindelia species.
Positive Results for Concurrently Secure Computation in the Plain Model

We consider the question of designing concurrently self-compos able protocols in the plain model. We first focus on the minimal setting where there is a party \pa which might interact with several other parties in any unbounded (polynomial) number of concurrent sessions. \pa holds a single input $x$ which it uses in all the concurrent sessions. An analogy is a server interacting with various clients at the same time. In this ``single input" setting, we show that many (or even most) functionalities can be securely realized in the plain model. More precisely, we are able to realize all ideal functionalities except ones which are a (weak form of) cryptographic pseudorandom functions. We complement our positive result by showing an impossibility result in this setting for a functionality which evaluates a pseudorandom function. Our security definition follows the standard ideal/real world simulation paradigm (with no super polynomial simulation etc). There is no apriori bound on the number of concurrent executions. We also show interesting extensions of our positive results to the more general setting where the honest parties may choose different inputs in different session (even adaptively), the roles that the parties assume in the protocol may be interchangeable, etc. Prior to our work, the only positive results known in the plain model in the fully concurrent setting were for zero-knowledge.
Phosphonium-mediated cyclization of N-(2-aminophenyl)thioureas: efficient synthesis of 2-aminobenzimidazoles

Abstract BOP efficiently promoted the phosphonium-mediated cyclization of thioureas, leading to a convenient synthesis of 2-aminobenzimidazoles. Compared to conventional methods, the reactions were complete at room temperature with times ranging from a few minutes to 1 h in near quantitative yields. This method is also applicable to the synthesis of more challenging structures such as 2-akylaminobenzimidazoles and 2-(N-acyl)-aminobenzimidazoles. The methodology described herein represents a mild and efficient route to a variety of 2-aminobenzimidazoles.
STRUCTURE IN THE INTERSTELLAR EXTINCTION CURVE

Using photographic techniques, it was attempted to obtain spectra of the interstellar material at a resolution of about 5 A. Three classes of structures are discussed. It is pointed out that the optical observations can be extended into the UV with a resolution of 0.4 A using the OAO-C telescope. The far UV observations would make it possible to conduct an extended search for new diffuse features, in order to evaluate the significance of the apparent absence of any features short of 4,430 A.
An application of the "coloring problem": structure-composition-bonding relationships in the magnetocaloric materials LaFe13-xSix.

The LaFe(13)-(x)Si(x) (1.0 < or = x < or = 5.0) series is studied experimentally and theoretically to gain possible understanding for the relationships among geometrical structure, chemical composition, magnetic behavior, and physical properties as related to the magnetocaloric effect in these compounds. As the Si concentration increases, LaFe(13)-(x)Si(x) exhibits a structural transformation from the cubic NaZn(13) structure type to a tetragonal derivative due primarily to preferential ordering of Fe and Si atoms. At room temperature, LaFe(13)-(x)Si(x) crystallize in the cubic structure for the range 1 < or = x < or = 2.6 and in the tetragonal for 3.2 < or = x < or = 5. In the range 2.6 < or = x < or = 3.2, it shows a two-phase mixture. Temperature-dependent single-crystal X-ray diffraction experiments near the corresponding Curie temperatures were performed on the room-temperature cubic phases to examine the origin of the large isothermal magnetic entropy changes. A thorough statistical and structural analysis of the data indicates that the noncentrosymmetric F43c space group provides a more adequate atomic arrangement than the centrosymmetric Fm3c space group. This change in space group leads to divergence for specific sets of Fe-Fe distances below the Curie temperature that arises from tilting of Fe-centered [Fe(12)-(x)Si(x)] icosahedra. The noncentrosymmetric space group also agrees with the predominance of icosahedral clusters lacking local inversion symmetry. From extended Huckel and tight-binding linear muffin-tin orbital (TB-LMTO) electronic structure calculations on various model structures, the F43c model is more energetically favorable than the Fm3c model. Extended Huckel calculations on various icosahedral [Fe(12)-(n)Si(n)] (n = 1-5) clusters and TB-LMTO calculations on "LaFe(13)," LaFe(11)Si(2), and LaFe(9)Si(4) have also been carried out to study the effects of a main group element (Si) on stabilizing the cubic NaZn(13)-type structure, influencing the transformation between cubic and tetragonal symmetries, and to study relationships among their chemical bonding and magnetic properties.
SPECTROSCOPY OF M81 GLOBULAR CLUSTERS

We obtained spectra of 74 globular clusters (GCs) in M81. These GCs had been identified as candidates in a Hubble Space Telescope (HST) Advanced Camera for Surveys I-band survey. Sixty-eight of these 74 clusters lie within 7' of the M81 nucleus. Sixty-two of these clusters are newly spectroscopically confirmed, more than doubling the number of confirmed M81 GCs from 46 to 108. We determined metallicities for our 74 observed clusters using an empirical calibration based on Milky Way GCs. We combined our results with 34 M81 GC velocities and 33 metallicities from the literature and analyzed the kinematics and metallicity of the M81 GC system. The mean of the total sample of 107 metallicities is –1.06 ± 0.07, higher than either M31 or the Milky Way. We suspect that this high mean metallicity is due to an overrepresentation of metal-rich (MR) clusters in our sample created by the spatial limits of the HST I-band survey. The metallicity distribution shows marginal evidence for bimodality, with the mean metallicities of MR and metal-poor (MP) GCs similar to those of M31 and the Milky Way. The GC system as a whole, and the MP GCs alone, show evidence of a radial metallicity gradient. The M81 GC system as a whole shows strong evidence of rotation, with V r (deprojected) = 108 ± 22 km s–1 overall. This result is likely biased toward high rotational velocity due to overrepresentation of MR inner clusters. The rotation patterns among GC subpopulations are roughly similar to those of the Milky Way: clusters at small projected radii and MR clusters rotate strongly, while clusters at large projected radii and MP clusters show weaker evidence of rotation.
AHF: array-based half-facet data structure for mixed-dimensional and non-manifold meshes

We present an Array-basedHalf-Facet mesh data structure, or AHF, for efficient mesh query and modification operations. The AHF extends the compact array-based half-edge and half-face data structures (T. J. Alumbaugh and X. Jiao, Compact array-based mesh data structures, IMR, 2005) to support mixed-dimensional and non-manifold meshes. The design goals of our data structure include generality to support such meshes, efficiency of neighborhood queries and mesh modification, compactness of memory footprint, and facilitation of interoperability of mesh-based application codes. To accomplish these goals, our data structure uses sibling half-facets as a core abstraction, coupled with other explicit and implicit representations of entities. A unique feature of our data structure is a comprehensive implementation in MATLAB, which allows rapid prototyping, debugging, testing, and deployment of meshing algorithms and other mesh-based numerical methods. We have also developed a C++ implementation built on top of MOAB (T.J. Tautges, R. Meyers, and K. Merkley, MOAB: A Mesh-Oriented Database, Sandia National Laboratories, 2004). We present some comparisons of the memory requirements and computational costs, and also demonstrate its effectiveness with a few sample applications.
ONE-POT SYNTHESIS OF ω-CHLOROESTERS VIA THE REACTION OF ACID CHLORIDES WITH TETRAHYDROFURAN IN THE PRESENCE OF TRICHLOROBORANE

ABSTRACT The reaction of acid chlorides with tetrahydrofuran in the presence of trichloroborane produces ω-chloroesters in excellent yields.
Status of the SCA-FEL

Abstract The SCA-FEL can now provide FEL beams to users in a wavelength range extending from longer than 3.5 to shorter than 0.5 μm. Harmonic generation can extend the short-wavelength range. As an example of the operational characteristics, during a 3 week run in May–June 1989, the SCA-FEL provide 18 days of FEL beam at 16–18 hours/day. The FEL operated at 3.5 μm, and in a 20% band centered at 1.54 μm. 30 W of optical power was extracted in 3 ms macropulses with a 0.08% line width and a 3 ps micropulse.
Joint source-channel coding for scalable video

An approach towards joint source-channel coding for wireless video transmission at low bit rates is proposed. An SNR scalable video coder is used and a different amount of error protection is allowed for each scalable layer. Our problem is to allocate the available bit rate across scalable layers and, within each layer, between source and channel coding, while minimizing the end-to-end distortion of the received video sequence. The distortion is due to both source coding (quantization) errors and channel noise errors, and is measured in terms of the Mean Squared Error (MSE). The optimization algorithm utilizes rate-distortion characteristic plots. These plots show the contribution of each layer to the total distortion as a function of the source rate of the layer and the residual bit error rate (the error rate that remains after the use of channel coding). The plots are obtained experimentally using representative video sequences and show the sensitivity of the source encoder and decoder to channel errors. Our algorithm is operationally optimal given the rate- distortion characteristic plots. These plots are used in conjunction with plots that show the bit error rate achieved by the allowable channel coding schemes for given channel conditions in order to obtain the operational rate-distortion curve of each layer. Then, dependent Lagrangian optimization is used to determine the overall bit allocation across all layers.© (2000) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
FLAMINGOS Spectroscopy of New Low-Mass Members of the Young Cluster IC 348

We present spectroscopy of candidate stellar and substellar members of the young cluster IC 348. Using the Florida Multi-Object Imaging Near-Infrared Grism Observational Spectrometer with the 4 m telescope at Kitt Peak National Observatory, we have obtained multiobject moderate-resolution (R = 1000) J- and H-band spectra of 66 infrared sources (H = 12-17) toward IC 348, many of which are difficult to observe spectroscopically at optical wavelengths (I > 20) because they are highly reddened and/or intrinsically cool and red. We have also observed 19 known cluster members that have optical spectral types available from previous work. By using these latter sources as the spectral classification standards, we have identified 14 new members of the cluster with types M2-M6 in the sample of 66 new objects. Two additional objects exhibit types later than M8.5 but cannot be conclusively classified as either field dwarfs or cluster members with available data. We have estimated extinctions, luminosities, and effective temperatures for these 16 M-type objects, placed them on the H-R diagram, and used the evolutionary models of Chabrier & Baraffe to estimate their masses. If the two candidates at later than M8.5 are indeed members, they should be among the least massive known brown dwarfs in IC 348 (M/M☉ ~ 0.01).
Dye Sensitization of Nanocrystalline Tin Oxide by Perylene Derivatives

A new sensitizing dye−semiconductor system comprised of perylene derivatives on SnO2 has been characterized. The tetracarboxylic acid form (“PTCA”) of the commercially available dye perylene-3,4,9,10-tetracarboxylic dianhydride and the novel compound perylene-3,4-dicarboxylic acid-9,10-(5-phenanthroline)carboximide (“PPDCA”) adsorb strongly to the surface of colloidal films of SnO2 and inject electrons into the semiconductor film upon absorption of light. A film of PPDCA on SnO2 yields a short circuit photocurrent density of 3.26 mA/cm2, a photovoltage of −0.45 V, and an overall cell efficiency of 0.89% at one sun light intensity. Estimates of the oxidation potential of adsorbed PPDCA indicate that it may also be useful in a water-splitting configuration. The results presented here indicate that the perylene−SnO2 system is a promising dye−semiconductor combination and warrants further study.
Synthesis and chemistry of a facially dissymmetric cage-condensed p-benzoquinone; a synthetic entry into novel doubly-caged systems

Abstract The synthesis of a novel caged quinone, 1, is reported. Diels-Alder cycloaddition of cyclopentadiene to 1 results in the formation of two endo adducts, 2a and 2b, each of which can be photocyclized to the corresponding “doubly-caged” diketone (3a and 3b, respectively).
Evaluating the Economic Significance of Downward Nominal Wage Rigidity

Abstract The existence of downward nominal wage rigidity has been abundantly documented, but what are its economic implications? This paper demonstrates that, even when wages are allocative, downward wage rigidity can be consistent with weak macroeconomic effects. Firms have an incentive to compress wage increases as well as wage cuts when downward wage rigidity binds. By neglecting compression of wage increases, previous literature may have overstated the costs of downward wage rigidity to firms. Using micro-data from the US and Great Britain, I find that the evidence for the compression of wage increases when downward wage rigidity binds. Accounting for this reduces the estimated increase in aggregate wage growth due to wage rigidity to be much closer to zero. These results suggest that downward wage rigidity may not provide a strong argument against the targeting of low inflation rates.
Frobenius Problem and dead ends in integers

Abstract Let a and b be positive and relatively prime integers. We show that the following are equivalent: (i) d is a dead end in the (symmetric) Cayley graph of Z with respect to a and b , (ii) d is a Frobenius value with respect to a and b (it cannot be written as a non-negative or non-positive integer linear combination of a and b ), and d is maximal (in the Cayley graph) with respect to this property. In addition, for given integers a and b , we explicitly describe all such elements in Z . Finally, we show that Z has only finitely many dead ends with respect to any finite symmetric generating set. In Appendix A we show that every finitely generated group has a generating set with respect to which dead ends exist.
Quantum control of qubits and atomic motion using ultrafast laser pulses

Pulsed lasers offer significant advantages over continuous wave (CW) lasers in the coherent control of qubits. Here we review the theoretical and experimental aspects of controlling the internal and external states of individual trapped atoms with pulse trains. Two distinct regimes of laser intensity are identified. When the pulses are sufficiently weak that the Rabi frequency Ω is much smaller than the trap frequency ωtrap, sideband transitions can be addressed and atom-atom entanglement can be accomplished in much the same way as with CW lasers. By contrast, if the pulses are very strong Ω ≫ ωtrap, impulsive spin-dependent kicks can be combined to create entangling gates which are much faster than a trap period. These fast entangling gates should work outside of the Lamb-Dicke regime and be insensitive to thermal atomic motion.
Gender and savings in rural India.

In this study we use data from rural India to examine the impact of the birth of a boy relative to the birth of a girl (i.e., the “gender shock”) on the savings, consumption and income of rural Indian households. We find that the gender shock reduces savings for medium and large farm households, although there is no evidence that the shock affects savings for the landless and the small farm households. We also estimate the effect of the shock on income and consumption for the former group in order to determine the source of the drop in savings. The results indicate that the fall in savings subsequent to the gender shock arises from its effect on consumption in the year following the birth, and from its effect on income in other years.
Security in sensor networks: industry trends, present and future research directions

Security is of critical importance for the successful deployment of sensor networks, since it can ensure properties such as data integrity, secrecy, and availability. We have the unique opportunity to ensure security even for early deployments of sensor networks, which could avoid alarming news articles and help fend off corporate and consumer security and privacy fears. In this talk, I will discuss the most important security issues in sensor networks, present realistic attacker models, comment on industry trends for achieving security, and highlight present and future research directions.
Au-containing all-carbon 1,4-dipoles: generation and [4 + 2] annulation in the formation of carbo-/heterocycles.

A novel concept of Au-containing all-carbon 1,n-dipoles is advanced. From 1-(1-alkynyl)cyclopropyl ketones, Au-containing all-carbon 1,4-dipoles are presumably generated in situ and can efficiently...
Adaptive resonance theory

SyNAPSE program of the Defense Advanced Projects Research Agency (Hewlett-Packard Company, subcontract under DARPA prime contract HR0011-09-3-0001, and HRL Laboratories LLC, subcontract #801881-BS under DARPA prime contract HR0011-09-C-0001); CELEST, an NSF Science of Learning Center (SBE-0354378)
Electron-vibrational dynamics of photoexcited polyfluorenes.

The highly polarizable π-electron system of conjugated molecules forms the basis for their unique electronic and photophysical properties, which play an important role in numerous biological phenomena and make them important materials for technological applications. We present a theoretical investigation of the dynamics and relaxation of photoexcited states in conjugated polyfluorenes, which are promising materials for display applications. Our analysis shows that both fast (∼20 fs) and slow (∼1 ps) nuclear motions couple to the electronic degrees of freedom during the excited-state dynamics. Delocalized excitations dominate the absorption, whereas emission comes from localized (self-trapped) excitons. This localization is attributed to an inherent nonlinear coupling among vibronic degrees of freedom which leads to lattice and torsional distortions and results in specific signatures in spectroscopic observables. Computed vertical absorption and fluorescence frequencies as well as photoluminescence band sh...
Variational Evolution Problems and Nonlocal Geometric Motion

We consider two variational evolution problems related to Monge-Kantorovich mass transfer. These problems provide models for collapsing sandpiles and for compression molding. We prove the following connection between these problems and nonlocal geometric curvature motion: The distance functions to surfaces moving according to certain nonlocal geometric laws are solutions of the variational evolution problems. Thus we do the first step of the proof of heuristics developed in earlier works. The main techniques we use are differential‐equation methods in the Monge‐Kantorovich theory.
Lymphoma monocyte crosstalk via HSP27 to promote immune suppression and chemotherapy resistance

Meeting abstracts Immune editing is a major mechanism used by tumors to promote its survival. We have reported previously the presence of a novel phenotype of immunosuppressive monocytes (CD14+HLA-DRlow/neg) in a number of cancers. Increased presence of these cells was associated with decreased
Hippocrates à la mode.

At graduation, many medical students recite oaths vague in precept and betraying a self-solicitude inimical to professional maturity.
Stochastic Belief Propagation: A Low-Complexity Alternative to the Sum-Product Algorithm

The belief propagation (BP) or sum-product algorithm is a widely used message-passing method for computing marginal distributions in graphical models. At the core of the BP message updates, when applied to a graphical model involving discrete variables with pairwise interactions, lies a matrix-vector product with complexity that is quadratic in the state dimension d, and requires transmission of a (d-1)-dimensional vector of real numbers (messages) to its neighbors. Since various applications involve very large state dimensions, such computation and communication complexities can be prohibitively complex. In this paper, we propose a low-complexity variant of BP, referred to as stochastic belief propagation (SBP). As suggested by the name, it is an adaptively randomized version of the BP message updates in which each node passes randomly chosen information to each of its neighbors. The SBP message updates reduce the computational complexity (per iteration) from quadratic to linear in d, without assuming any particular structure of the potentials, and also reduce the communication complexity significantly, requiring only log2d bits transmission per edge. Moreover, we establish a number of theoretical guarantees for the performance of SBP, showing that it converges almost surely to the BP fixed point for any tree-structured graph, and for any graph with cycles satisfying a contractivity condition. In addition, for these graphical models, we provide nonasymptotic upper bounds on the convergence rate, showing that the l∞ norm of the error vector decays no slower than O (1/√t) with the number of iterations t on trees and the normalized mean-squared error decays as O (1/t) for general graphs. This analysis, also supported by experimental results, shows that SBP can provably yield reductions in computational and communication complexities for various classes of graphical models.
Multivariate quality control based on regression-adjusted variables

When performing quality control in a situation in which measures are made of several possibly related variables, it is desirable to use methods that capitalize on the relationship between the variables to provide controls more sensitive than those that may be made on the variables individually. The most common methods of multivariate quality control that assess the vector of variables as a whole are those based on the Hotelling T 2 between the variables and the specification vector. Although T 2 is the optimal single-test statistic for a general multivariate shift in the mean vector, it is not optimal for more structured mean shifts-for example, shifts in only some of the variables. Measures based on quadratic forms (like T 2) also confound mean shifts with variance shifts and require quite extensive analysis following a signal to determine the nature of the shift. This article proposes Shewhart and cumulative sum (CUSUM) controls based on the vector Z of scaled residuals from the regression of each varia...