cssi/SciSciGPT-SciSciNet huggingface dataset:
List-decoding of subspace codes and rank-metric codes up to Singleton bound

Subspace codes and rank-metric codes can be used to correct errors and erasures in network, with linear network coding. Both types of codes have been extensively studied in the past five years. Subspace codes were introduced by Koetter and Kschischang to correct errors and erasures in networks where topology is unknown (the non-coherent case). In this model, the codewords are vector subspaces of a fixed ambient space; thus codes for this model are collections of such subspaces. In a previous work, we have developed a family of subspace codes, based upon the Koetter-Kschichang construction, which are efficiently list decodable. Using these codes, we achieved a better decoding radius than Koetter-Kschischang codes at low rates. Herein, we introduce a new family of subspace codes based upon a different approach which leads to a linear-algebraic list-decoding algorithm. The resulting error-correction radius can be expressed as follows: for any integer s, our list-decoder using s + 1-variate interpolation polynomials guarantees successful recovery of the message sub-space provided the normalized dimension of errors is at most s(1 − sR). The same list-decoding algorithm can be used to correct erasures as well as errors. The size of output list is at most Qs − 1, where Q is the size of the field that message symbols are chosen from. Rank-metric codes are suitable for error correction in the case where the network topology and the underlying network code are known (the coherent case). Gabidulin codes are a well-known class of algebraic rank-metric codes that meet the Singleton bound on the minimum rank-distance of a code. In this paper, we introduce a folded version of Gabidulin codes analogous to the folded Reed-Solomon codes of Guruswami and Rudra along with a list-decoding algorithm for such codes. Our list-decoding algorithm makes it possible to recover the message provided that the normalized rank of error is at most 1 − R − ∊, for any ∊ > 0. Notably this achieves the information theoretic bound on the decoding radius of a rank-metric code.
Wilderness: options to preserve, extract, or develop

Option-pricing is used to evaluate the sequence and timing of wilderness preservation, resource extraction, and development. Resource extraction or development results in the permanent destruction of wilderness and the loss of an amenity dividend. Resource extraction does not preclude subsequent development. If the wilderness is directly developed (without prior extraction of resources), wilderness and resource extraction options are both killed. Starting from a state of wilderness, there are two stochastically evolving barriers, one for the price of the resource, and the other for the return on development. Wilderness is preserved provided the price of the resource never catches the price barrier and the return on development never catches the return barrier.
Arbitrary rank jumps for A‐hypergeometric systems through Laurent polynomials

We investigate the solution space of hypergeometric systems of differential equations in the sense of Gel?fand, Graev, Kapranov and Zelevinski. For any integer d 2, we construct a matrix A(d) d x 2d and a parameter vector s(d) such that the holonomic rank of the A-hypergeometric system HA(d)(s(d)) exceeds the simplicial volume vol(A(d)) by at least d ? 1. The largest previously known gap between rank and volume was 2. Our construction gives evidence to the general observation that rank jumps seem to go hand in hand with the existence of multiple Laurent (or Puiseux) polynomial solutions
Real effects of separating investment and operating cash flows

This paper investigates the rationale for the measurement of a firm's periodic performance through the accounting classification of its cash outflows into operating cash flow and investment. We show that when the accounting system does not attempt to measure periodic performance and reports only aggregate cash flow, equilibrium capital market prices are such that there is a perverse informational cost to investment over and above the real cost of investment. This induces distortions in the firms' equilibrium investment. We show that other sources of information, consisting of forecasts of future returns to investment play a vital counterbalancing role when the accounting system is inadequate in this way. An accounting signal that provides noisy information on periodic performance decreases the informational cost to investment and moves the economy closer to first best.
Operadic formulation of topological vertex algebras and Gerstenhaber or Batalin-Vilkovisky algebras

We give the operadic formulation of (weak, strong) topological vertex algebras, which are variants of topological vertex operator algebras studied recently by Lian and Zuckerman. As an application, we obtain a conceptual and geometric construction of the Batalin-Vilkovisky algebraic structure (or the Gerstenhaber algebra structure) on the cohomology of a topological vertex algebra (or of a weak topological vertex algebra) by combining this operadic formulation with a theorem of Getzler (or of Cohen) which formulates Batalin-Vilkovisky algebras (or Gerstenhaber algebras) in terms of the homology of the framed little disk operad (or of the little disk operad).
A view from the AIAA: Introduction of new energy storage technology into orbital programs

Abstract The development of new energy storage technology must be heavily weighted toward the application. The requirements for transitioning low risk technolog
Synthesis of pyrrolobenzodiazepines via the PIFA oxidation of amines. Synthesis of 8-deoxy DC-81

Abstract PIFA can be used to introduce the imine moiety into a precursor to the pyrrolobenzodiazepines in 62% yield. This oxidation completes an efficient four-step synthesis of 8-deoxy DC-81.
Little M-theory

Using the language of theory space, i.e. moose models, we develop a unified framework for studying composite Higgs models at the LHC. This framework — denoted little M-theory — is conveniently described by a theoretically consistent three-site moose diagram which implements minimal flavor and isospin violation. By taking different limits of the couplings, one can interpolate between simple group-like and minimal moose-like models with and without T-parity. In this way, little M-theory reveals a large model space for composite Higgs theories. We argue that this framework is suitable as a starting point for a comprehensive study of composite Higgs scenarios. The rich collider phenomenology of this framework is briefly discussed.
Spatial coherence of the thermal electromagnetic field in the vicinity of a dielectric slab.

We present the analytic calculation of the cross-spectral density tensor of a thermally radiative planar dielectric slab in extreme near-field, intermediate near-field, and far-field zones. We show that the spatial coherence of the thermal field exhibits distinct features in these zones. At a given wavelength $\ensuremath{\lambda}$, the coherence length is many orders of magnitude smaller than $\ensuremath{\lambda}$ in the extreme near-field zone, and is roughly $\ensuremath{\lambda}∕2$ in the far-field zone. In the intermediate near-field zone, the coherence length can be much longer than $\ensuremath{\lambda}∕2$ if the loss is small. The physical origin of the short-ranged spatial coherence in the extreme near-field zone is the spatially fluctuating surface charges at the air-dielectric interface. We also demonstrate that in the intermediate near-field zone, the long-ranged spatial coherence is induced by the waveguide modes of the dielectric slab. When the loss is small, the long-ranged coherence falls off approximately as $1∕\sqrt{x}$, in contrast to $1∕x$ for a blackbody radiator, where $x$ refers to displacement parallel to the slab surface.
Physical observables from lattice QCD at fixed topology

Abstract Because present Monte Carlo algorithms for lattice QCD may become trapped in a given topological charge sector when one approaches the continuum limit, it is important to understand the effect of calculating at fixed topology. In this work, we show that although the restriction to a fixed topological sector becomes irrelevant in the infinite volume limit, it gives rise to characteristic finite size effects due to contributions from all θ-vacua. We calculate these effects and show how to extract physical results from numerical data obtained at fixed topology.
Chemical Specificity in Nanomechanical Sensors

¶ Corresponding authors Advances in the field of micro/nano-electro-mechanical systems (MEMS and NEMS) now offer unique opportunities in the design of small and ultrasensitive analytical methods. MEMs/NEMs have demonstrated their unique advantages when they are combined with chemistry and biology, including fast, real-time responses. In addition, MEMs and NEMS are small enough to be integrated into other devices. One of the most promising MEMs is microcantilevers, which have been proven to be an outstanding transducer for chemical and biological sensors. This review summarizes the receptors and immobilization approaches reported for nanomechanical sensors and interpret the mechanism and dynamic relationship of recognition induced nanomechanical motions. Since the three pioneer papers (1-3) published in 1994, the micro/nanocantilever sensor technology had boomed and become a promising sensor technology. Microcantilever sensors have several advantages over many other sensor technologies, including faster response time, lower cost of fabrication, the possibility of sensor arrays with small overall dimensions, the ability to explore microenvironments, and improved portability for field applications. SEM pictures of microcantilevers are shown in Fig. (1). Microcantilevers are miniature diving boards that are micromachined from silicon or other materials. The length of these cantilevers is often in the range of 100-200 microns while the thickness ranges from 200 -1000 nm; Recent advances in micromachining cantilever beams that can detect extremely small forces and mechanical stresses promise to bring about a revolution in the field of chemical, physical, and biological sensor development.
F-Theory, T-Duality on K3 Surfaces and N = 2 Supersymmetric Gauge Theories in Four Dimensions

We construct T-duality on K3 surfaces. The T-duality exchanges a 4-brane R-R charge and a O-brane R-R charge. We study the action of the T-duality on the moduli space of O-branes located at points of K3 and 4-branes wrapping it. We apply the construction to F-theory compactified on a Calabi-Yau 4-fold and study the duality of N = 2 SU(N{sub c}) gauge theories in four dimensions. We discuss the generalization to the N = 1 duality scenario.
A space-charge-sheath electric thruster.

T method of electric propulsion discussed in this note consists of accelerating cesium, which has been ionized on the surface of a porous tungsten plug, in the space-charge sheath located between the ionizer and a plasma filled region, t The flow of the plasma electrons to the ionizer is inhibited by a magnetic field parallel to the ionizer surface. The magnetic-field strength (up to a maximum of 2500 gauss in the experiment) at the ionizer is such that the average electron-cyclotron radius is comparable to the length of the accelerating gap (of the order of 1 mm) between ionizer and plasma, whereas the ion motion is essentially unaffected by the magnetic field. More detailed considerations show that the accelerating gap represents a double space-charge sheath, with a positive net charge near the ionizer and a negative net charge near the plasma region. The device resembles in some respects the so-called Hallcurrent accelerators investigated by others." However, whereas the acceleration of the ions in Hall-current devices takes place in the interior of a quasi-neutral plasma over distances that are large compared with both a Debye length and with an electron-cyclotron radius, in the device described here, the ions are accelerated in a space-charge sheath. The sheath thickness is comparable to an electron-cyclotron radius. This distinction between the two types of devices is illustrated in Fig. 1. Since, in the Hall-current device, the plasma in the accelerating region is approximately charge neutral, the thrust density is not limited by space-charge effects. In the device discussed in this note, high thrust-densities are still possible despite space-charge limitations, provided the gap between the anode and the virtual cathode is sufficiently small. In Hall-current devices, energy and momentum transfer from the plasma to the walls is an important loss mechanism. This loss is essentially absent in the space-charge-sheath device, since the plasma beam is effectively confined by the inertia of the accelerated ions and is nowhere in contact with material boundaries. The remainder of this note is confined to a discussion of the ion and electron motion in the accelerating region of the device. The calculations are in some respects similar to known analyses of electron trajectories in magnetrons and crossed-field devices, but have added complexity due to the presence of positive ions whose motions in the combined electric and magnetic fields are treated self-consistently, together with those of the electrons.
Measurement of nonlinear mode coupling of tearing fluctuations

Three-wave nonlinear coupling of spatial Fourier modes is measured in the MST reversed field pinch by applying bispectral analysis to magnetic fluctuations measured at the plasma edge at 64 toroidal locations and 16 poloidal locations, permitting observation of coupling over 8 polodial modes and 32 toroidal modes. Comparison to bispectra predicted by resistive MHD computation indicates reasonably good agreement. However, during the crash phase of the sawtooth oscillation the nonlinear coupling is strongly enhanced, concomitant with a broadened (presumably nonlinearly generated) k spectrum.
Dynamics of elastocapillary rise

We present the results of a combined experimental and theoretical investigation of the surface-tension-driven coalescence of flexible structures. Specifically, we consider the dynamics of the rise of a wetting liquid between flexible sheets that are clamped at their upper ends. As the elasticity of the sheets is progressively increased, we observe a systematic deviation from the classical diffusive-like behaviour: the time to reach equilibrium increases dramatically and the departure from classical rise occurs sooner, trends that we elucidate via scaling analyses. Three distinct temporal regimes are identified and subsequently explored by developing a theoretical model based on lubrication theory and the linear theory of plates. The resulting free-boundary problem is solved numerically and good agreement is obtained with experiments.
Airplanes for Everyone: A General Education Course for Non‐Engineers

The Department of Aeronautics and Astronautics, at the University of Washington, has introduced a new course to non-engineering students. This course is distinguished by the fact that it is specifically designed for non-engineering/science students. The course, called AA101: Air and Space Vehicles, fulfills a “natural world” graduation requirement for University undergraduates. This course has proven so popular that after the first offering it has filled the auditorium and all lab sections every quarter. It is now being offered three quarters a year. AA101 includes hands-on learning, multi-media presentations, and classroom demonstrations. Lab sections each week demonstrate principles learned in class and are usually centered about a fun activity. Examples include learning to fly with Microsoft Flight Simulator, building a rubber powered balsa airplane, and launching water rockets. In several of these activities, teamwork is stressed. A conscious decision in the creation of the course was to eliminate analysis in order to attract the broadest audience. Graduates of AA101 are thus familiar with the concepts but cannot apply analytical tools to aerospace engineering.
The kinetics of propylene metathesis catalyzed by a molybdenum (100) single crystal

Abstract It is shown, using a high-pressure reactor incorporated into an ultrahigh-vacuum chamber, that an initially clean molybdenum (100) single crystal can catalyze propylene metathesis. The reaction is found to be first-order in propylene pressure which proceeds with a high activation energy (∼65 kcal/mol). Auger spectroscopy reveals the presence of a thick (∼10 monolayers) carbonaceous layer on the surface of the catalyst following reaction. It is further demonstrated, using restart reactions, that metathesis proceeds in presence of this layer. However, the reaction prefactor is ∼ 8 × 1012 site−1 s−1 so that the reaction appears not to be drastically inhibited by the presence of the carbonaceous layer, rather, the high reaction activation energy is primarily responsible for the low rate. Methylcyclopropane and hydrogenolysis products are also formed in the reaction, an observation that is consistent with the reaction proceeding at the surface via the "carbene" mechanism.
The general theory of irreversible processes in solutions of macromolecules

The general theory of irreversible processes in solutions of macromolecules, previously formulated by the author, is reviewed. The theory is based upon the Oseen method for determining the perturbation in the hydrodynamic flow pattern produced by the frictional forces exerted by the macromolecule on the solvent, and on a generalized theory of Brownian motion in molecular configuration space. Applications of theory to viscoelastic behavior, flow birefringence, and the Kerr effect, and to dielectric dispersion are presented in outline.
Antimatroids and Balanced Pairs

We generalize the $\frac{1}{3}$ – $\frac{2}{3}$ conjecture from partially ordered sets to antimatroids: we conjecture that any antimatroid has a pair of elements x,y such that x has probability between $\frac{1}{3}$ and $\frac{2}{3}$ of appearing earlier than y in a uniformly random basic word of the antimatroid. We prove the conjecture for antimatroids of convex dimension two (the antimatroid-theoretic analogue of partial orders of width two), for antimatroids of height two, for antimatroids with an independent element, and for the perfect elimination antimatroids and node search antimatroids of several classes of graphs. A computer search shows that the conjecture is true for all antimatroids with at most six elements.
Outcomes of primary surveillance for intraductal papillary mucinous neoplasm.

Limited data are available regarding the natural history of patients undergoing primary surveillance for intraductal papillary mucinous neoplasm (IPMN). We hypothesize that symptoms, radiologic characteristics, and cytopathology will predict cancer risk during surveillance. Between March 2002 and March 2010, 522 patients were diagnosed with IPMN at a single, high-volume institution. Low versus high oncologic risk was stratified prospectively. Patients with under 3 months of surveillance were excluded. Two hundred ninety-two patients underwent primary surveillance for IPMN. Two hundred forty-four (84%) were classified as low-risk IPMN. Mean surveillance duration was 35 (4–99) months. Thirty (12%) patients initially stratified as low-risk developed a new indication for pancreatic resection. Only 28 underwent resection, and pathologic tissue analysis revealed 27 (96%) low-grade IPMN and one (4%) high-grade dysplastic IPMN. Overall, two (1%) patients initially determined to be low-risk developed invasive cancer. Forty-eight (16%) patients stratified as high-risk IPMN were initially managed nonoperatively. Of the 13 (27%) high-risk patients that died during follow-up, two (15%) died from pancreatic cancer. Progression to pancreatic cancer during surveillance for low-risk IPMN was rare. Current indications for resection did not forecast malignancy. Poor operative candidates with high-risk IPMN progressed to invasive cancer more commonly, though a substantial portion succumbed to non-IPMN-related death.
Far-Infrared Spectral Energy Distributions and Photometric Redshifts of Dusty Galaxies

We infer the large-scale source parameters of dusty galaxies from their observed spectral energy distributions (SEDs) using the analytic radiative transfer methodology presented by Chakrabarti and McKee. For local ultraluminous infrared galaxies (ULIRGs), we show that the millimeter to far-infrared (FIR) SEDs can be well fit using the standard dust opacity index of 2 when self-consistent radiative transfer solutions are employed, indicating that the cold dust in local ULIRGs can be described by a single-grain model. We develop a method for determining photometric redshifts of ULIRGs and submillimeter galaxies from the millimeter-FIR SED; the resulting value of 1 + z is typically accurate to about 10% . As such, it is comparable to the accuracy of near-IR photometric redshifts and provides a complementary means of deriving redshifts from far-IR data, such as those from the upcoming Herschel Space Observatory. Since our analytic radiative transfer solution is developed for homogeneous, spherically symmetric, centrally heated, dusty sources, it is relevant for infrared bright galaxies that are primarily powered by compact sources of luminosity that are embedded in a dusty envelope. We discuss how deviations from spherical symmetry may affect the applicability of our solution, and we contrast our self-consistent analytic solution with standard approximations to demonstrate the main differences.
Commuting maps on rank-k matrices

Abstract Let n ⩾ 2 be a natural number. Let M n ( K ) be the ring of all n × n matrices over a field K . Fix natural number k satisfying 1 k ⩽ n . Under a mild technical assumption over K we will show that additive maps G : M n ( K ) → M n ( K ) such that [ G ( x ) , x ] = 0 for every rank-k matrix x ∈ M n ( openK ) are of form λ x + μ ( x ) , where λ ∈ Z , μ : M n ( K ) → Z , and Z stands for the center of M n ( K ) . Furthermore, we shall see an example that there are additive maps such that [ G ( x ) , x ] = 0 for all rank-1 matrices that are not of the form λ x + μ ( x ) .
Comparative studies on bacterial cytochromes.

Abstract 1. 1. All photosynthetic bacteria appear to contain cytochromes of the “c” type together with associated enzymic activities, such as DPNH-linked reductase, oxidase and photo-oxidase. This is true of strict anaerobes as well as facultative bacteria. There also appears to be a general distribution of other hematin compounds, such as cytochromes of the “b” type, as well as of the new hematin compounds tentatively referred to as “pseudohemoglobins”. 2. 2. Two species of denitrifiers (facultative anaerobes) have also been examined and found to contain cytochromes of the “c” type. One of these species yields a cytochrome c which spectroscopically and enzymically resembles mammalian cytochrome c, whereas the other contains a cytochrome very similar in spectroscopic properties, oxidation potential and enzymic behavior to the cytochromes of “c” type found in photosynthetic bacteria. 3. 3. The oxidation potentials of the various cytochromes of “c” type have been measured over a wide range of pH values. These results indicate that each microorganism examined has a cytochrome c unique to itself, but that all the “c” cytochromes isolated from the facultative photohetertrophs have potentials much more oxidizing than those of cytochrome c as prepared from yeast or mammalian tissue. 4. 4. These results are discussed and correlated with the overall physiology of the bacteria. Their significance for the general problem of transfer and storage of light energy in photosynthesis is indicated.
Integral Congruence Two Hyperbolic 5-Manifolds

In this paper, we classify all the orientable hyperbolic 5-manifolds that arise as a hyperbolic space form H 5/Γ where Γ is a torsion-free subgroup of minimal index of the congruence two subgroup Γ 5 2 of the group Γ 5 of positive units of the Lorentzian quadratic form x 2/1 +... +x 5/2 -x 6/2. We also show that Γ 5 2 is a reflection group with respect to a 5-dimensional right-angled convex polytope in H 5. As an application, we construct a hyperbolic 5-manifold of smallest known volume 7ζ (3)/4.
Symmetric iterated Betti numbers

We define a set of invariants of a homogeneous ideal I in a polynomial ring called the symmetric iterated Betti numbers of I. We prove that for IΓ, the Stanley-Reisner ideal of a simplicial complex Γ, these numbers are the symmetric counterparts of the exterior iterated Betti numbers of Γ introduced by Dural and Rose, and that the extremal Betti numbers of IΓ are precisely the extremal (symmetric or exterior) iterated Betti numbers of Γ. We show that the symmetric iterated Betti numbers of an ideal I coincide with those of a particular reverse lexicographic generic initial ideal Gin(I) of I, and interpret these invariants in terms of the associated primes and standard pairs of Gin(I). We close with results and conjectures about the relationship between symmetric and exterior iterated Betti numbers of a simplicial complex.
Catalyzed Catalysis Using Carbophilic Lewis Acidic Gold and Lewis Basic Palladium: Synthesis of Substituted Butenolides and Isocoumarins

A new strategy for gold and palladium dual-catalytic reactivity and turnover, called catalyzed catalysis, enhanced the synthetic usefulness of vinylgold intermediates by providing dual-catalytic carbon−carbon cross-coupling as an alternative to protodemetalation. This protocol enabled the synthesis of substituted butenolides and isocoumarins from allyl esters. Kinetic and spectroscopic experiments support a mechanism in which the Lewis acidic gold complex catalyzes both an initial rearrangement step and a subsequent Lewis basic palladium oxidative-addition step.
Three-dimensional two-pion emission source at SPS: Extraction of source breakup time and emission duration

A model-independent, three-dimensional source function for pion pairs has been extracted from Pb + Pb collisions at √sNN = 17.3 GeV. The extracted source exhibits long-range non-Gaussian tails in the directions of the pion-pair net transverse momentum and of the beam. Comparison with the Therminatormodel allows for an extraction of the pion source proper breakup time and of emission duration in the collisions.
Automated ARGET ATRP Accelerates Catalyst Optimization for the Synthesis of Thiol-Functionalized Polymers.

Conventional synthesis of polymers by ATRP is relatively low throughput, involving iterative optimization of conditions in an inert atmosphere. Automated, high-throughput controlled radical polymerization was developed to accelerate catalyst optimization and production of disulfide-functionalized polymers without the need of an inert gas. Using ARGET ATRP, polymerization conditions were rapidly identified for eight different monomers, including the first ARGET ATRP of 2-(diethylamino)ethyl methacrylate and di(ethylene glycol) methyl ether methacrylate. In addition, butyl acrylate, oligo(ethylene glycol) methacrylate 300 and 475, 2-(dimethylamino)ethyl methacrylate, styrene, and methyl methacrylate were polymerized using bis(2-hydroxyethyl) disulfide bis(2-bromo-2-methylpropionate) as the initiator, tris(2-pyridylmethyl)amine as the ligand, and tin(II) 2-ethylhexanoate as the reducing agent. The catalyst and reducing agent concentration was optimized specifically for each monomer, and then a library of pol...
Magnetically Recoverable Chiral Catalysts Immobilized on Magnetite Nanoparticles for Asymmetric Hydrogenation of Aromatic Ketones

Novel heterogenized asymmetric catalysts were synthesized by immobilizing preformed Ru catalysts on magnetite nanoparticles via the phosphonate functionality and were characterized by a variety of techniques, including TEM, magnetization, and XRD. These nanoparticle-supported chiral catalysts were used for enantioselective heterogeneous asymmetric hydrogenation of aromatic ketones with very high enantiomeric excess values of up to 98.0%. The immobilized catalysts were easily recycled by magnetic decantation and reused for up to 14 times without loss of activity and enantioselectivity. Orthogonal nature of the present catalyst immobilization approach should allow the design of other superparamagnetic nanoparticle-supported asymmetric catalysts for a wide range of organic transformations.
Confidence intervals for low dimensional parameters in high dimensional linear models

Summary The purpose of this paper is to propose methodologies for statistical inference of low dimensional parameters with high dimensional data. We focus on constructing confidence intervals for individual coefficients and linear combinations of several of them in a linear regression model, although our ideas are applicable in a much broader context. The theoretical results that are presented provide sufficient conditions for the asymptotic normality of the proposed estimators along with a consistent estimator for their finite dimensional covariance matrices. These sufficient conditions allow the number of variables to exceed the sample size and the presence of many small non-zero coefficients. Our methods and theory apply to interval estimation of a preconceived regression coefficient or contrast as well as simultaneous interval estimation of many regression coefficients. Moreover, the method proposed turns the regression data into an approximate Gaussian sequence of point estimators of individual regression coefficients, which can be used to select variables after proper thresholding. The simulation results that are presented demonstrate the accuracy of the coverage probability of the confidence intervals proposed as well as other desirable properties, strongly supporting the theoretical results.
The albedo and scattering phase function of interstellar dust and the diffuse background at far-ultraviolet wavelengths

The diffuse FUV background in a variety of targets has been observed with a nebular spectrometer designed specifically to eliminate potential sources of contamination. The intensity of the background near the Galactic plane is found to be much lower than previously published. The data are analyzed using a radiative transfer model with a limited set of free parameters, including those which describe the scattering properties of the interstellar dust. Strong evidence is presented that scattering of starlight by Galactic dust associated with neutral hydrogen produces the major part of the FUV diffuse background. Few assumptions are necessary to conclude that the albedo of the grains is low in the FUV. The grains, at least at high latitude, scatter fairly isotropically in the FUV. The low FUV albedo and the usual phase factor g are not consistent with predictions of standard models for the size distribution and composition of interstellar grains.
Drug Delivery Systems Based on Trimethyl Lock Lactonization: Poly(ethylene glycol) Prodrugs of Amino-Containing Compounds

A novel methodology for the synthesis of poly(ethylene glycol) (PEG) prodrugs of amino-containing compounds has been developed which is based on the trimethyl lock lactonization reaction. These PEG-modified double prodrugs are water soluble, and by selective modification of the specifier or trigger, plasma half-lives can be adjusted at will to result in a wide range of values. Facile syntheses of ester, carbonate, and carbamate functionalities were accomplished and combined with greater or lesser degrees of steric hindrance in the spacer group, or on the aromatic framework, to achieve predictable ranges of drug concentration in plasma. In vivo screening of PEG prodrugs was done using a M109 syngeneic solid mouse tumor model. One of the PEG-daunorubicin prodrugs, with a half-life of 2 h, was evaluated in an in vivo solid tumor panel and found to be more efficacious against ovarian tumors (SKOV3) than equivalent amounts of daunorubicin.
Conversion of aldehydes to α-acetoxymethyl ketones: One-carbon homologation with (benzotriazol-1-yl)phenoxymethane

Abstract Reaction of aldehydes with (benzotriazol-1-yl)phenoxymethyl anion afforded the corresponding addition products which, upon treatment with p -toluenesulfonic acid in acetic acid, yielded the corresponding α-acetoxymethyl ketones.
Densification of Reaction‐Synthesized Titanium Carbide by High‐Velocity Forging

A novel process for the manufacture of dense titanium carbide is described. Titanium carbide is produced by the reaction synthesis method, while densification and near-net shaping is accomplished by a high-velocity forging step. Disks with 10-cm diameter were produced with densities over 96% of the theoretical density. The major problem encountered in this study has been thermal shock. Use of insulation and furnace cooling has decreased the severity of this problem. Optical and scanning electron microscopy observations of the resulting microstructure reveal equiaxed grains with an average size of 44 μm. Quasi-static and high-strain-rate compressive strength measurements yield values greater than 1.7 and 2.2 GPa, respectively. The morphologies of thermally induced (slow) and rapidly propagating cracks were characterized and the fracture modes were found to be intergranular and transgranular, respectively. The addition of Ni (5 and 25 wt%) yielded a ceramic–metal composite with a favorable microstructure.
Stress-optical analysis of fluids

Recent advances in Rheology have emphasized the necessity of measuring the stress distribution in flowing viscoelastic fluids which is qualitatively different from the one in Newtonian liquids. The use of flow-birefringence for this purpose has advantages. The concept of the stress-optical coefficient, well known in the stress optical analysis of solids, can be also applied to fluid flow. The extinction angle determines the “recoverable shear strain,s” a parameter in the flow of viscoelastic fluids. This would mean that mechanical and optical flow phenomena are caused primarily by stresses, not by the rate of shear. Experimental results presented confirm this postulate.
Coherent Neutrino Scattering in Dark Matter Detectors

Coherent elastic neutrino-nucleus and weakly interacting massive particle-nucleus interaction signatures are expected to be quite similar. This paper discusses how a next-generation ton-scale dark matter detector could discover neutrino-nucleus coherent scattering, a precisely-predicted standard model process. A high-intensity pion- and muon- decay-at-rest neutrino source recently proposed for oscillation physics at underground laboratories would provide the neutrinos for these measurements. In this paper, we calculate raw rates for various target materials commonly used in dark matter detectors and show that discovery of this interaction is possible with a $2\text{ }\text{ }\mathrm{ton}\ifmmode\cdot\else\textperiodcentered\fi{}\mathrm{year}$ GEODM exposure in an optimistic energy threshold and efficiency scenario. We also study the effects of the neutrino source on weakly interacting massive particle sensitivity and discuss the modulated neutrino signal as a sensitivity/consistency check between different dark matter experiments at the Deep Underground Science and Engineering Laboratory. Furthermore, we consider the possibility of coherent neutrino physics with a GEODM module placed within tens of meters of the neutrino source.
Applications of Gas Imaging Micro- Well Detectors to an Advanced Compton Telescope

We present a concept for an Advanced Compton Telescope (ACT) based on the use of pixelized gas micro-well detectors to form a three-dimensional electron track imager. A micro-well detector consists of an array of individual micro-patterned proportional counters opposite a planar drift electrode. When combined with thin film transistor array readouts, large gas volumes may be imaged with very good spatial and energy resolution at reasonable cost. The third dimension is determined by timing the drift of the ionization electrons. The primary advantage of this approach is the excellent tracking of the Compton recoil electron that is possible in a gas volume. Such good electron tracking allows us to reduce the point spread function of a single incident photon dramatically, greatly improving the imaging capability and sensitivity. The polarization sensitivity, which relies on events with large Compton scattering angles, is particularly enhanced. We describe a possible ACT implementation of this technique, in which the gas tracking volume is surrounded by a CsI calorimeter, and present our plans to build and test a small prototype over the next three years.
Evidence for differential rotation on a T Tauri Star

Five years of photometric monitoring of the T Tauri star HBC 338 in NGC 1333 has revealed that it is a periodic variable, but the period has changed significantly with time. From 2000 to 2003, a period near 5.6 days was observed, while in the last two seasons, the dominant period is near 4.6 days. No other T Tauri star has been seen to change its period by such a large percentage. We propose a model in which a differentially rotating star is seen nearly equator-on and a high-latitude spot has gradually been replaced by a low-latitude spot. We show that this model provides an excellent fit to the observed shapes of the light curves at each epoch. The amplitude and sense of the inferred differential rotation are similar to what is seen on the Sun. This may be surprising, given the likely high degree of magnetic surface activity on the star relative to the Sun, but we note that HBC 338 is clearly an exceptional T Tauri star. Online material: color figure
A Canonical Quantization of the Baker's Map

Abstract We present here a canonical quantization for the baker's map. The method we use is quite different from that used in Balazs and Voros and Saraceno. We first construct a natural “baker covering map” on the plane R 2. We then use as the quantum algebra of observables the subalgebra of operators onL2( R ) generated by {exp(2πix), exp(2πip)}. We construct a unitary propagator such that as ħ→0 the classical dynamics is returned. For Planck's constanth=1/N, we show that the dynamics can be reduced to the dynamics on anN-dimensional Hilbert space, and the unitaryN×Nmatrix propagator is the same as given by Balazs and Voros, except for a small correction of orderh. This correction is shown to preserve the classical symmetryx→1−xandp→1−pin the quantum dynamics for periodic boundary conditions.
Subsonic and Transonic Similarity Rules for Jet-Flapped Wings

Abstract : Linear-subsonic and nonlinear-transonic similarity rules are derived for a finite-span jet-flapped wing with partial or full-span blowing. Although some subsonic rules previously have been published for jet-flapped wings, those presented herein are more general. The nonlinear transonic rules are new. The rules for both flow regimes employ a new jet-sheet compatibility condition that is second order relative to the jet-sheet internal flow and yields a jet-momentum coefficient similarity parameter differing from the conventional parameter in that it includes the effect of the jet-supply pressure ratio. The examples presented show that the second-order effect is significant only for conditions under which a convergent jet nozzle chokes at a relatively low free-stream Mach number, say, less than 0.5. The relation of the present rules to previously published rules for both blown and unblown wings is discussed briefly. The experimental data available for validation of the linear rules is rather sparse and is plagued with uncertainties regarding wind-tunnel interference corrections. Nevertheless, some comparisons with experiment are made and fair agreement is achieved. These comparisons revealed that camber-line effects associated with blowing could be significant in transonic applications. There is no experimental data of appropriate configurational simplicity and of sufficient generally in parametric variations to permit validation of the nonlinear rules. (Author)
Enantioselective C−C Bond Formation by Rhodium-Catalyzed Tandem Ylide Formation/[2,3]-Sigmatropic Rearrangement between Donor/Acceptor Carbenoids and Allylic Alcohols

The rhodium-catalyzed reaction of racemic allyl alcohols with methyl phenyldiazoacetate or methyl styryldiazoacetate results in a two-step process, an initial oxonium ylide formation followed by a [2,3]-sigmatropic rearrangement. This process competes favorably with the more conventional O−H insertion chemistry as long as donor/acceptor carbenoids and highly substituted allyl alcohols are used as substrates. When the reactions are catalyzed by Rh2(S-DOSP)4, tertiary α-hydroxycarboxylate derivatives with two adjacent quaternary centers are produced with high enantioselectivity (85−98% ee).
A simple and effective procedure for removal of tri-n-butyltin halides from reaction mixtures

Abstract A mixture of powdered 2:1, CsF:CsOH (solid solution) and silica gel can be used conveniently to remove Bu 3 SnHal from non-polar organic coproducts.
Electron transfer in the quenching of protonated triplet thionine and methylene blue by ground state thionine

Abstract The quenching of the monoprotonated lowest triplet state of thionine (3TH22+) by ground state thionine (TH+) was investigated by laser flash photolysis—kinetic spectrophotometry employing frequency-doubled (347.2 nm) flashes from a Q-switched ruby laser. The quenching of the monoprotonated lowest triplet state of methylene blue (3MBH2+) by TH+ was similarly investigated using the fundamental (694.3 nm) ruby frequency. In 0.01 M acid the quenching of 3TH22+ by TH+ is accompanied by net electron transfer to give the semi-oxidized radical (TH2 +) and the semi-reduced radical (TH2+ ) while the quenching of 3MBH2+ by TH+ is accompanied by the net one-electron oxidation of 3MBH2+ by TH+ to give MB2 + and TH2+. Spectra of TH2 + and TH2+ in water, 50 vol.% aqueous CH3CN and 50 vol.% aqueous C2H5OH in the presence of 0.01 M acid were characterized. The dependence of the specific rate kq of quenching and the specific rate ket of net electron transfer for the quenching of 3TH22+ by TH+ on the solvent composition, the nature of the anions and the salt concentration was investigated. The efficiency F1 (= ket/kq) of net electron transfer in the quenching of 3TH22+ by TH+ correlates with Kosower's solvent polarity parameter Z as it does in the quenching of 3MBH2+ by a reversible electron transfer mechanism, namely ln[1/F1) — 1∼ varies linearly with Z. Values of kq and ket for the quenching of 3MBH2+ by TH+ are similar to those for the quenching of 3MBH2+ by ground state methylene blue (MB+) and about one-tenth of those for the quenching of 3TH22+ by TH+ in the same media. Values of F1 for the quenching of 3TH22+ by TH+ differ little from those for the quenching of 3MBH2+ by MB+ in the same media except that increased salt concentration sharply reduces F1 in the former case and does not significantly affect it in the latter. Values of F1 for the quenching of 3MBH2+ by TH+ are substantially lower than for the homogeneous cases. The mechanism of crossed and homogeneous ground state quenching and the implications of ground state quenching for the efficiency of Fe—thiazine photogalvanic cells are discussed.
Programming pattern recognition

Everyone likes to speculate, and recently there has been a lot of talk about reading machines and hearing machines. We know it is possible to simulate speech. This raises lots of interesting questions such as: If the machines can speak, will they squawk when you ask them to divide by zero? And can two machines carry on an intelligent conversation, say in Gaelic? And, of course, there is the expression "electronic brain" and the question, Do machines think? These questions are more philosophical than technical and I am going to duck them.
A geometric interpretation of the neutrosophic set — A generalization of the intuitionistic fuzzy set

In this paper we give a geometric interpretation of the Neutrosophic Set using the Neutrosophic Cube. Distinctions between the neutrosophic set and intuitionistic fuzzy set are also presented.
Application of a panel method to hydrodynamics of underwater vehicles

A low-order singularity panel method based on Green's formulation is used to predict the hydrodynamics characteristics of underwater vehicles. The low-order modeling employs constant strength sources and doublets, and the body surface is modeled by quadrilaterals. The method is first applied to predicting the force and moment coefficients of underwater vehicles for the body-alone and finned configurations. Hydrodynamic coefficients of added mass and added moment of inertia are also calculated by modifying the code. Results for several two and three-dimensional bodies show the usefulness of the method for predicting the added mass and added moment of inertia.
FRACTURE SURFACE CHARACTERISTICS OF UNFILLED THERMOSETS.

Many of the features that cause the great complexity of the fracture surfaces of thermosets are suggested to have a simple explanation. These features include the “basic longitudinal texture,” “steps,” “welts,” “arrays of skewed cracks,” and the “stacked lamellar texture.” The explanation for their occurrence is based on the hypothesis of an instability of the propagating crack front that produces a “fingering” ahead of the crack.
A scaling limit with many noncommutativity parameters

Abstract We derive the worldsheet propagator for an open string with different magnetic fields at the two ends, and use it to compute two distinct noncommutativity parameters, one at each end of the string. The usual scaling limit that leads to noncommutative Yang–Mills can be generalized to a scaling limit in which both noncommutativity parameters enter. This corresponds to expanding a theory with U ( N ) Chan–Paton factors around a background U (1) N gauge field with different magnetic fields in each U (1).
Parallel image processing with the block data parallel architecture

Many digital signal and image processing algorithms can be speeded up by executing them in parallel on multiple processors. The speed of parallel execution is limited by the need for communication and synchronization between processors. In this paper, we present a paradigm for parallel processing that we call the block data flow paradigm (BDFP). The goal of this paradigm is to reduce interprocessor communication, and relax the synchronization requirements for such applications. We present the block data parallel architecture which implements this paradigm, and we present methods for mapping algorithms onto this architecture. We illustrate this methodology for several applications including two-dimensional (2-D) digital filters, the 2-D discrete cosine transform, QR decomposition of a matrix, and Cholesky factorization of a matrix. We analyze the resulting system performance for these applications with regard to speedup and efficiency as the number of processors increases. Our results demonstrate that the block data parallel architecture is a flexible, high-performance solution for numerous digital signal and image processing algorithms.
Detection of Single Ion Spectra by Coulomb Crystal Heating

The coupled motion of ions in a radiofrequency trap has been used to connect the frequency-dependent laser-induced heating of a sympathetically cooled spectroscopy ion with changes in the fluorescence of a laser-cooled control ion. This technique, sympathetic heating spectroscopy, is demonstrated using two isotopes of calcium. In the experiment, a few scattered photons from the spectroscopy ion are transformed into a large deviation from the steady-state fluorescence of the control ion. This allows us to detect an optical transition where the number of scattered photons is below our fluorescence detection limit. Possible applications of the technique to molecular ion spectroscopy are briefly discussed.