cssi/SciSciGPT-SciSciNet huggingface dataset:
Discovery of jet quenching and beyond

Abstract Recent observation of high- p T hadron spectra suppression and mono-jet production in central Au + Au collisions and their absence in d + Au collisions at RHIC have confirmed the long predicted phenomenon of jet quenching in high-energy heavy-ion collisions. Detailed analysis of the experimental data also show parton energy loss as the mechanism for the discovered jet quenching. Using a pQCD parton model that incorporates medium modified parton fragmentation functions and comparing to experimental data from deeply inelastic scattering off nuclei, one can conclude that the initial gluon (energy) density of the hot matter produced in central Au + Au collisions that causes jet quenching at RHIC is about 30 (100) times higher than in a cold Au nucleus. Combined with data on bulk and collective properties of the hot matter, the observed jet quenching provides strong evidence for the formation of a strongly interacting quark–gluon plasma in central Au + Au collisions at RHIC.
Convergent synthesis of peptide conjugates using dehydroalanines for chemoselective ligations

[reaction: see text]. Protein and peptide conjugates such as glycopeptides, prenylated peptides, and lipopeptides play essential roles in biology. A rapid and convergent entry into a variety of these compounds is described. The methodology involves the introduction of a dehydroalanine into peptides and subsequent chemoselective conjugate addition of an appropriate thiolate nucleophile, including farnesylthiolate or thioglycosides.
Binary Merger Progenitors for Gamma-Ray Bursts and Hypernovae

The collapsar model, the now leading model for the engine behind gamma-ray bursts and hypernovae, requires that a star collapses to form a black hole surrounded by an accretion disk of high angular momentum material. The current best theoretical stellar models, however, do not retain enough angular momentum in the core of the star to make a centrifugally supported disk. In this paper, we present the first calculations of the helium star/helium star merger progenitors for the collapsar model. These progenitors invoke the merger of two helium cores during the common-envelope inspiral phase of a binary system. We find that in some cases, the merger can produce cores that are rotating 3-10 times faster than single stars. He star/He star gamma-ray burst progenitors have a very different redshift distribution than their single-star gamma-ray burst progenitors, and we discuss how gamma-ray burst observations can constrain these progenitors.
Totally frustrated states in the chromatic theory of gain graphs

We generalize proper coloring of gain graphs to totally frustrated states, where each vertex takes a value in a set of 'qualities' or 'spins' that is permuted by the gain group. In standard coloring the group acts trivially or regularly on each orbit (an example is the Potts model), but in the generalization the action is unrestricted. We show that the number of totally frustrated states satisfies a deletion-contraction law. It is not matroidal except in standard coloring, but it does have a formula in terms of fundamental groups of edge subsets. One can generalize chromatic polynomials by constructing spin sets out of repeated orbits. The dichromatic and Whitney-number polynomials of standard coloring generalize to evaluations of an abstract partition function that lives in the edge ring of the gain graph.
Deconstructing gaugino mediation

Abstract We present a model of supersymmetry breaking which produces gaugino masses and negligible scalar masses at a high scale. The model is inspired by “deconstructing” or “latticizing” models in extra dimensions where supersymmetry breaking and visible matter are spatially separated. We find a simple four-dimensional model which only requires two lattice sites (or gauge groups) to reproduce the phenomenology.
Shock Vorticity Generation from Accelerated Ion Streaming in the Precursor of Ultrarelativistic Gamma-Ray Burst External Shocks

We investigate the interaction of nonthermal ions (protons and nuclei) accelerated in an ultrarelativistic blast wave with the preexisting magnetic field of the medium into which the blast wave propagates. While particle acceleration processes such as diffusive shock acceleration can accelerate ions and electrons, the accelerated electrons suffer larger radiative losses. Under certain conditions, the ions can attain higher energies and reach farther ahead of the shock than the electrons, and so the nonthermal particles can be partially charge separated. To compensate for the charge separation, the upstream plasma develops a return current, which, as it flows across the magnetic field, drives transverse acceleration of the upstream plasma and a growth of density contrast in the shock upstream. If the density contrast is strong by the time the fluid is shocked, vorticity is generated at the shock transition. The resulting turbulence can amplify the postshock magnetic field to the levels inferred from gamma-ray burst afterglow spectra and light curves. Therefore, since the upstream inhomogeneities are induced by the ions accelerated in the shock, they are generic even if the blast wave propagates into a medium of uniform density. We speculate about the global structure of the shock precursor and delineate several distinct physical regimes that are classified by an increasing distance from the shock and, correspondingly, a decreasing density of nonthermal particles that reach that distance.
Negative influence of O-linked oligosaccharides of high molecular weight equine chorionic gonadotropin on its luteinizing hormone and follicle-stimulating hormone receptor-binding activities.

Three equine CG (eCG) forms with identical amino acid sequences but different mol wt and monosaccharide compositions were isolated from a crude eCG preparation and designated eCG-L (low mol wt), eCG-M (medium mol wt), and eCG-H (high mol wt). No differences in primary structure between each form and the known sequence of eCG were observed. SDS-PAGE of these preparations under reducing conditions revealed that the mol wt differences between them were due only to the different sizes of their beta-subunits. Carbohydrate compositions suggested an increase in O-glycosylation in the higher mol wt forms. N-Linked glycopeptide fragments obtained from eCG beta-subunits by endoproteinase Lys-C digestion had identical electrophoretic mobilities. Thus, the different molecular sizes of the beta-subunits were associated only with disparities in O-glycosylation of their C-terminal extension. When tested in a LH and several FSH radioligand assay systems, eCG-H proved to have significantly lower receptor-binding activitie...
Efficiency, productivity, and scale economies in the U.S. property-liability insurance industry

The paper examines efficiency, productivity and scale economies in the U.S. property-liability insurance industry. Productivity change is analyzed using Malmquist indices, and efficiency is estimated using data envelopment analysis. The results indicate that the majority of firms below median size in the industry are operating with increasing returns to scale, and the majority of firms above median size are operating with decreasing returns to scale. However, a significant number of firms in each size decile have achieved constant returns to scale. Over the sample period, the industry experienced significant gains in total factor productivity, and there is an upward trend in scale and allocative efficiency. More diversified firms and insurance groups were more likely to achieve efficiency and productivity gains. Higher technology investment is positively related to efficiency and productivity improvements.
Adaptive frameless rendering

We propose an adaptive form of frameless rendering with the potential to dramatically increase rendering speed over conventional interactive rendering approaches. Without the rigid sampling patterns of framed renderers, sampling and reconstruction can adapt with very fine granularity to spatio-temporal color change. A sampler uses closed-loop feedback to guide sampling toward edges or motion in the image. Temporally deep buffers store all the samples created over a short time interval for use in reconstruction and as sampler feedback. GPU-based reconstruction responds both to sampling density and space-time color gradients. Where the displayed scene is static, spatial color change dominates and older samples are given significant weight in reconstruction, resulting in sharper and eventually antialiased images. Where the scene is dynamic, more recent samples are emphasized, resulting in less sharp but more up-to-date images. We also use sample reprojection to improve reconstruction and guide sampling toward occlusion edges, undersampled regions, and specular highlights. In simulation our frameless renderer requires an order of magnitude fewer samples than traditional rendering of similar visual quality (as measured by RMS error), while introducing overhead amounting to 15% of computation time.
Remarkable regioselectivity in microwave-enhanced palladium-catalyzed allylation reaction involving allyltrifluoroborates and aryl halides

Abstract An unprecedented cross-coupling reaction of potassium allyltrifluoroborates and aryl halides to the corresponding trans- β - methylstyrenes in the presence of PdCl 2 (d t bpf) catalyst under microwave heating was developed.
A new approach to indole alkaloids via indole chromium complexes

Abstract The activating effect of pi complexation of a Cr(CO) 3 unit allows selective nucleophilic substitution in indoles such as tryptophan derivatives and provides intermediates for the synthesis of clavicipitic acid and related indole natural products.
Improving the usability of programming publications

In mid-1979, a study group was convened at the IBM Santa Teresa Laboratory to find ways to improve the usability of publications supporting the Laboratory's programming products.1 The group, called the System Information Ease-of-Use Study Group, consisted of technical writers, editors, and information planners---all members of the System Information (i.e., programming publications) Department at the Laboratory. The study group was asked to answer the question: "What can the planners, writers, and editors of programming publications do to make the books they work on more usable?"
The synthesis and evaluation of cyclic ureas as hiv protease inhibitors : Modifications of the P1/P1' residues

Abstract Two series of cyclic ureas modified at the P1/P1′ residue were prepared and evaluated for HIV protease inhibition and whole cell antiviral activity. Compounds 8b, 10 (3- and 4-pyridylmethyl analogs) and 6b (4-methoxy analog) showed significant improvement in antiviral activity relative to lead compounds DMP323 and DMP 450.
Use of the "single suture" technique to expose the anterior surface of the heart.

Abstract The “single suture” technique, which consists of placing a suture in the oblique sinus of the posterior pericardium and connecting it to a vaginal tape, is commonly adopted in off-pump coronary artery revascularization to obtain elevation of the heart and coronary artery exposure. This report describes the use of this technique to expose the anterior wall of the heart in the setting of ventricular aneurysm repair.
Mixed valence in conjugated anion radicals, solution and solid state studies

Abstract Electron localization in anion radicals of aromatic compounds built with two electrophores was studied using Vis, NIR, IR and ESR spectroscooy and electrochemistry. N,N′,-Bis (2,5-di-tert-butylphenyl)-2,3,6,7-anthracene-docarboximide anion radical has the odd electron mainly localized on the anthracene bridge. This contrasts with its diquinone analog, 1,4,8,11-pentacenetetrone, which has the odd electron localized on one quinone at a time. The anion radical of the tatrakis-(N-cyanoimine) derivative of 5,7,12,14-pentacenetetrone (3−) is delocalized. The solid state conductivity of the salts M+, 3− ranges from 10−4 S cm−1 for M=Bu4N to 0.4 S cm−1 for M=Na
Physical layer security with uncoordinated helpers implementing cooperative jamming

1 A wireless communication network is considered, consisting of a source, a destination and an eavesdropper, each equipped with a single antenna. The communication is assisted by multiple multi-antenna helpers, which independently transmit jamming noise to confound the eavesdropper. The optimal structure of the jamming noise that maximizes the secrecy rate is derived. A suboptimal solution that results in nulling at the legitimate receiver is also considered. Unlike the optimal solution, which requires global channel information, the suboptimal solution requires local channel information only, i.e., each helper needs to know only its own channel to the destination. Although the nulling solution results in lower secrecy rate as compared to the optimal solution, simulations show that the difference is rather small, with the inexpensive and easy to implement nulling scheme performing near optimal.
STEREOTYPE THREAT AND THE STUDENT‐ATHLETE

Achievement gaps may reflect the cognitive impairment thought to occur in evaluative settings (e.g., classrooms) where a stereotyped identity is salient (i.e., stereotype threat). This study presents an economic model of stereotype threat that reconciles prior evidence on how student effort and performance are influenced by this social-identity phenomenon. This study also presents empirical evidence from a framed field experiment in which students at a selective college were randomly assigned to a treatment that primed their awareness of a negatively stereotyped identity (i.e., student-athlete). This social-identity manipulation reduced the test-score performance of athletes relative to non-athletes by 12%. These negative performance effects were concentrated among male student-athletes who also responded to the social-identity manipulation by attempting to answer more questions. (JEL I2, C9, D0)
Univariate and multivariate random field models for images

Abstract The paper introduces a special type of univariate random field model, the so-called periodic random field models, for describing homogenous images (not necessarily isotropic). For modeling nonhomogeneous images, we introduce multivariate random field models. In the case of a univariate random field, scalar autoregressive representation on a lattice is used. In the case of a multivariate random field, vector or multivariate autoregressive representation on the lattice is discussed. For the univariate model, we discuss in detail the derivation of the expression for the probability density of the data, and the maximum likelihood estimation of the unknown parameters in the model. Using statistical decision theory we indicate the development of decision rules for the choice of the neighbors, the homogeneity of the data, etc. We discuss in some detail the information aspects of the data, such as compression of the data without effectively losing any information, reconstruction of the data for the stored information. For the multivariate model we discuss only the problem of obtaining the probability density of the observations. In a subsequent paper, we will discuss further details of the multivariate model.
Magnetostratigraphy from downhole measurements in ODP holes

Abstract The “Geological High-resolution Magnetic Tool” (GHMT) was used on 17 ODP Legs to obtain downhole logs of magnetic field strength and magnetic susceptibility. The remanent magnetization of the sediment around the borehole is derived from these measurements, and used to produce magnetostratigraphies. This review of the ODP GHMT data indicates that reliable magnetostratigraphies can usually be obtained from reasonably well-magnetized (above approximately 10−3 A/m) fine-grained sediments. Additionally, the GHMT data indicates that a drill-string overprint, common in data collected on cores, does not significantly affect the sediments surrounding the borehole. This allows us to use the remanent and induced magnetization data to obtain estimates of relative paleointensity, and when averaged over time in homogenous sediment, the paleomagnetic recording efficiency of that sediment.
DIRECT IMAGING CONSTRAINTS ON THE PUTATIVE EXOPLANET 14 Her C

We present results of deep direct imaging of the radial velocity (RV) planet-host star 14 Her (=GJ 614, HD 145675), obtained in the L' band with the Clio-2 camera and the MMT adaptive optics system. This star has one confirmed planet and an unconfirmed outer companion, suggested by residuals in the RV data. The orbital parameters of the unconfirmed object are not well constrained since many mass/semimajor axis configurations can fit the available data. The star has been directly imaged several times, but none of the campaigns has ruled out sub-stellar companions. With {approx}2.5 hr of integration, we rule out at 5{sigma} confidence {approx}>18 M{sub J} companions beyond {approx}25 AU, based on the Baraffe et al. COND mass-luminosity models. Combining our detection limits with fits to the RV data and analytic dynamical analysis, we constrain the orbital parameters of 14 Her c to be 3 {approx}< m/M{sub J} {approx}<42, 7 {approx}< a/AU {approx}<25, and e {approx}< 0.5. A wealth of information can be obtained from RV/direct imaging overlap, especially with deep imaging as this work shows. The collaboration between RV and direct imaging will become more important in the coming years as the phase space probed by each technique converges.more » Future studies involving RV/imaging overlap should be sure to consider the effects of a potential planet's projected separation, as quoting limits assuming face-on orientation will be misleading.« less
Non-perturbative determination of heavy quark action coefficients

We propose to determine the coefficients in the Fermilab heavy quark action by matching the finite-volume, off-shell, gauge-fixed propagator and vertex functions with those determined in the exact, relativistic theory. The matching relativistic amplitudes may be determined either from short-distance perturbation theory or from finite-volume step-scaling recursion. Tree-level matching and non-perturbative off-shell amplitudes are presented.
Performance measures for single-degree-of-freedom energy harvesters under stochastic excitation

We develop performance criteria for the objective comparison of different classes of single-degree-of-freedom oscillators under stochastic excitation. For each family of oscillators, these objective criteria take into account the maximum possible energy harvested for a given response level, which is a quantity that is directly connected to the size of the harvesting configuration. We prove that the derived criteria are invariant with respect to magnitude or temporal rescaling of the input spectrum and they depend only on the relative distribution of energy across different harmonics of the excitation. We then compare three different classes of linear and nonlinear oscillators and using stochastic analysis methods we illustrate that in all cases of excitation spectra (monochromatic, broadband, white-noise) the optimal performance of all designs cannot exceed the performance of the linear design. Subsequently, we study the robustness of this optimal performance to small perturbations of the input spectrum and illustrate the advantages of nonlinear designs relative to linear ones.
New N- and O-arylations with phenylboronic acids and cupric acetate

Abstract A new method of arylating NH and OH containing compounds at room temperature with phenylboronic acids and cupric acetate in the presence of a tertiary amine promoter is described. Substrates include phenols, amines, anilines, amides, imides, ureas, carbamates, and sulfonamides.
The Economic Perspective on Public Administration

Public administration as a body of thought and field of study is changing from a paradigm dominated by political science to an eclectic array of theoretical contributions from all of the social sciences, particularly economics. Basic education and training in economics is essential to an effective contemporary public administration. Without a fundamental understanding of economics the “do-it-yourself-economics” which is practiced in policy-making contributes to basic errors in policy. As the size and significance of the public sector has grown, increased attention has been paid to the discipline of public administration. What began as a structured way of describing the operation and structure of public management and public organizations has evolved into a discipline that has a much broader scope—the analysis of policy making in the public and not-for-profit sectors. In addition, employment in the public administration profession is more likely to be viewed as a vocation rather than as an avocation, in co...
Hoxb5b acts downstream of retinoic acid signaling in the forelimb field to restrict heart field potential in zebrafish

How adjacent organ fields communicate during development is not understood. Here, we identify a mechanism in which signaling within the forelimb field restricts the potential of the neighboring heart field. In zebrafish embryos deficient in retinoic acid (RA) signaling, the pectoral fins (forelimbs) are lost while both chambers of the heart are enlarged. We provide evidence that both of these phenotypes are due to RA signaling acting directly within the forelimb field. hoxb5b, an RA-responsive gene expressed within the forelimb field, is required to restrict the number of atrial cells arising from the adjacent heart field, although its function is dispensable for forelimb formation. Together, these data indicate nonautonomous influences downstream of RA signaling that act to limit individual chamber size. Therefore, our results offer new perspectives on the mechanisms regulating organ size and the possible causes of congenital syndromes affecting both the heart and forelimb.
WISE/NEOWISE OBSERVATIONS OF THE JOVIAN TROJAN POPULATION: TAXONOMY

We present updated/new thermal model fits for 478 Jovian Trojan asteroids observed with the Wide-field Infrared Survey Explorer (WISE). Using the fact that the two shortest bands used by WISE, centered on 3.4 and 4.6 μm, are dominated by reflected light, we derive albedos of a significant fraction of these objects in these bands. While the visible albedos of both the C-, P-, and D-type asteroids are strikingly similar, the WISE data reveal that the albedo at 3.4 μm is different between C-/P- and D-types. The albedo at 3.4 μm can thus be used to classify the objects, with C-/P-types having values less than 10% and D-types have values larger than 10%. Classifying all objects larger than 50 km shows that the D-type objects dominate both the leading cloud (L 4), with a fraction of 84%, and trailing cloud (L 5), with a fraction of 71%-80%. The two clouds thus have very similar taxonomic distribution for these large objects, but the leading cloud has a larger number of these large objects, L 4/L 5 = 1.34. The taxonomic distribution of the Jovian Trojans is found to be different from that of the large Hildas, which is dominated by C- and P-type objects. At smaller sizes, the fraction of D-type Hildas starts increasing, showing more similarities with the Jovian Trojans. If this similarity is confirmed through deeper surveys, it could hold important clues to the formation and evolution of the two populations. The Jovian Trojans does have similar taxonomic distribution to that of the Jovian irregular satellites, but lacks the ultra red surfaces found among the Saturnian irregular satellites and Centaur population.
Neotame: Synthesis, Stereochemistry and Sweetness

Abstract Neotame, an alkylated dipeptide consisting of L,L-stereochemistry, is a new high intensity sweetener being developed by the Nutrition and Consumer Products Sector of Monsanto. The three diastereoisomers of neotame, L,D; D,L; and D,D were synthesized and evaluated for sweetness by sensory testing. Only the L,L-isomer was found to be sweet. The three-dimensional structure of the L,L diastereoisomer determined from single-crystal x-ray analysis demonstrates that the compound exists in an “L shaped” conformation, previously proposed for the requirement of the sweetness ability by aspartyl-based dipeptide compounds. The confirmation of neotame in the solid state also demonstrates well-oriented hydrophobic and hydrophilic regions which likely account for the high sweetness intensity of this dipeptide compound.
Composition of Blood of Normal Turkeys

Abstract VERY little information on the composition of the blood of normal turkeys is available. Scott, Serfontein, and Seiling (1933) state there is no published information of this kind prior to their report of the analysis of samples from fifteen young turkeys. We are unaware of any similar information published since then, except the tables on blood composition published by Duke (1942). In relation to an experiment being conducted with breeding turkeys it seemed desirable to determine whether the concentration of certain blood constituents of the hens could be related to fertility and hatchability of their eggs. MATERIALS AND METHODS All the turkeys used in this study were from the Experiment Station’s flock and had been on a feeding experiment for five months. The birds had been kept on alfalfa range and hopper fed mash, grain, and oyster shells. They were approximately sixteen months old at the time of the first . . .
THE ANISOTROPIC SPATIAL DISTRIBUTION OF HYPERVELOCITY STARS

We study the distribution of angular positions and angular separations of unbound hypervelocity stars (HVSs). HVSs are spatially anisotropic at the 3σ level. The spatial anisotropy is significant in Galactic longitude, not in latitude, and the inclusion of lower velocity, possibly bound HVSs reduces the significance of the anisotropy. We discuss how the observed distribution of HVSs may be linked to their origin. In the future, measuring the distribution of HVSs in the southern sky will provide additional constraints on the spatial anisotropy and the origin of HVSs.
Synthesis of β,β-Disubstituted Vinyl Boronates via the Ruthenium-Catalyzed Alder Ene Reaction of Borylated Alkynes and Alkenes

Ruthenium-catalyzed Alder ene reactions between borylated alkynes and terminal alkenes give the corresponding beta,beta-disubstituted vinyl boronates with high selectivity for the branched isomer. The stereochemistry of the vinyl boronate moiety was the result of a formal trans addition of the ene subunit across the alkyne, which is the opposite stereochemical outcome observed for other internal alkynes.
Anionic initiated coupling of tungsten carbene complexes: synthesis of the first (μ-tris(carbene))trimetallic complex

Abstract Treatment of (CO)5W[C(OCH3)C(CH3CH2] (1) with C2H5(CH3)2CONa in THF at −78°C followed by HCl produced: (CO)5W[C(OCH3)CH(CH3)CH2OC(CH3)2C2H5] (3) (1%), C2H5(CH3)2CO(CO)5W[C(OCH3)C(CH3)CH2]CH2C(CH3)CH(OCH3) (5) (
Remarks on Chern-Simons theory

In the late 1980s Witten used the Chern-Simons form of a connection to construct new invariants of 3-manifolds and knots, recovering in particular the Jones invariants. Since then the associated topological quantum field theory (TQFT) has served as a key example in understanding the structure of TQFTs in general. We survey some of that structure with a particular focus on the "multi-tier" aspects. We discuss general axioms, generators-and-relations theorems, a priori constructions, dimensional reduction and K-theory, and Chern-Simons as a 0-1-2-3 theory. An appendix gives a lightening treatment of the Chern-Simons-Weil theory of connections. The paper concludes with general remarks about the Geometry-QFT-Strings interaction.
A combinatorial abstraction of linear programming

Abstract In the context of oriented matroids we establish and elaborate upon an abstraction of linear programming duality foreseen by Rockafellar in his work on elementary vectors. We describe a pivoting operation for oriented matroids and a finite pivoting method, which elucidate the combinatorial nature of Dantzig's simplex method. The pivoting method specializes, when the oriented matroids arise from real vector spaces, to the simplex method with a new pivot selection rule. A very simple pivot selection rule for which finiteness has been established in the linear programming context, but not in the broader setting of oriented matroids, is also described.
Characteristics of laminated electrochromic devices using polyorganodisulfide electrodes

Abstract The application of polyorganodisulfides as optically passive counter-electrodes in a variety of electrochromic smart glazing devices are discussed. Characteristic data is presented for electrochromic devices using proton, and lithium coloration ions with modified polyethylene oxide electrolyte and polydimercaptothiadiazole positive electrodes. Solid state devices consisting of molybdenum doped WO 3 , amorphous polyethylene oxide electrolyte (a-PEO), and a polyorganodisulfide counter-electrode colored rapidly from a pale yellow to a deep blue-green, upon application of −1.2 V DC. The photopic transmittance ( T p ) changes from 61 to 9%, and the solar transmittance ( T s ) changes from 45 to 5% during the coloration process. Also, our experiments with polyimidazole are detailed. This family of compounds due to its unique electrical and ion conduction properties allow a single composite ion storage and ion conductor electrode to be made, simplifying the device construction. Devices made from this family of compounds color to deep blue-gray upon application of −1.2–1.5 V DC. Bleaching occurs at −0.4 to −0.5 V DC. The photopic transmittance changed from 55 to 9%, and the solar transmittance from 34 to 4% during coloration. Both coloration and bleaching are quite rapid.
Secondary instability of high‐speed flows and the influence of wall cooling and suction

The periodic streamwise modulation of the supersonic and hypersonic boundary layers by a two‐dimensional first‐mode or second‐mode wave makes the resulting base flow susceptible to a broadband spanwise‐periodic three‐dimensional type of instability. The principal parametric resonance of this instability (subharmonic) has been analyzed using Floquet theory. The effect of Mach number and the effectiveness of wall cooling or wall suction in controlling the onset, the growth rate, and the vortical structure of the subharmonic secondary instability are assessed for both a first‐mode and a second‐mode primary wave. Results indicate that the secondary subharmonic instability of an insulated wall boundary layer is weakened as Mach number increases. Cooling of the wall destabilizes the secondary subharmonic of a second‐mode primary wave, but stabilizes it when the primary wave is a first mode. Suction stabilizes the secondary subharmonic at all Mach numbers.
An implementation framework for trajectory-based routing in ad hoc networks

Routing in ad hoc networks is a complicated task because of many reasons. The nodes are low-memory, low-powered, and they cannot maintain routing tables large enough for well-known routing protocols. Because of that, greedy forwarding at intermediate nodes is desirable in ad hoc networks. Also, for traffic engineering, multi-path capabilities are important. So, it is desirable to define routes at the source like in source based routing (SBR) while performing greedy forwarding at intermediate nodes. We investigate trajectory-based routing (TBR) which was proposed as a middle-ground between SBR and greedy forwarding techniques. In TBR, source encodes trajectory to be traversed and embeds it into each packet. Upon the arrival of each packet, intermediate nodes decode the trajectory and employ greedy forwarding techniques such that the packet follows its trajectory as much as possible. In this paper, we address various issues regarding implementation of TBR. We also provide techniques to efficiently forward packets along a trajectory defined as a parametric curve. We use the well-known Bezier parametric curve for encoding trajectories into packets at source. Based on this trajectory encoding, we develop and evaluate various greedy forwarding algorithms
Preparation and thermodynamics of Some Homologous Nitrones, a New Group of Liquid Crystals

Abstract To investigate the mesomorphic behavior of aldonitrones, a series of 13 homologs of N-(p-alkoxyphenyl)-α-anisylnitrones was prepared and characterized. Although most of these substances exhibit normal nematic or smectic mesophases, the trend in nematic-isotropic transition temperatures to increase as a function of alkoxy chain length is an exceptional occurrence. Comparison of our data with that of analogous compounds previously reported indicates that thermal persistence of the nematic phase of these compounds increases in the following order : 4, 4′-dialkoxybenzylideneaniline, 4, 4′-dialkoxyazobenzene, N,α-di-(4-alkoxyphenyl)-nitrone, 4, 4′-dialkoxyazoxybenzene. In addition, the phase transitions were investigated by means of differential scanning calorimetry. The entropies of the mesophase-isotropic transitions of the nitrones imply that the long alkoxy chains, in contrast to a widely held belief, are not restricted to a single conformation in the mesophase.
B* probability based search

Keywords: Probabilistic B*, computer chess, selective search, two-person games 54 pages [FTP: Unavailable] We describe a search algorithm for two-player games that relies on selectivity rather than brute-force to achieve success. The key ideas behind the algorithm are: 1. Stopping when one alternative is clearly better than all the others, and 2. Focusing the search on the place where the most progress can likely be made toward being able to stop. Critical to this process is identifying uncertainty about the ultimate value of any move. The lower bound on uncertainty is the best estimate of the real value of a move, while the upper bound is its optimistic value, based on some measure of unexplored potential. Uncertainty is represented as probability densities. The search develops those parts of the tree where moving existing bounds would be most likely to succeed and make the most progress toward terminating the search. Termination is achieved when the established real value of the best move is so good that the likelihood of this being achieved by any other alternative is minimal. The B* probability based search algorithm has been implemented on the chess machine Hitech. "En route" we have developed effective techniques for: *Dealing with independence of alternative moves, *Producing viable optimistic estimates to guide the search and *Dealing with the Graph History Interaction problem. This report describes the implementation, and the results of tests including games played against brute-force programs. The data indicate that B* Hitech is a better pure selective searcher than anything previously reported. Further, analysis of the data indicates that should additional power become available, the B* technique will scale up considerably better than brute-force techniques.
Turbulent boundary-layer growth and separation on a yawed cone.

Turbulent and Laminar Wakes," AIAA Journal, Vol. 6, No. 10, Oct. 1968, pp. 2027-2029. 16 Clay, W. G., Herrmann, J., and Slattery, R. E., "Statistical Properties of the Turbulent Wake behind Hypervelocity Spheres," The Physics of Fluids, Vol. 8, 1965, pp. 1792-1801. 17 Schapker, R. L., "Statistics of High Speed Turbulent Wake Boundaries," AIAA Journal, Vol. 4, No. 11, Nov. 1966, pp. 1979-1987. is Herrmann, J. et al., "Some Statistical Properties of Turbulent Wakes," Specialists' Meeting of the Fluid Dynamics Panel of AGARD, AGARD Conference Proceedings 19, 1967. 19 Townsend, A. A., The Structure of Turbulent Shear Flows, Cambridge University Press, London, 1956. 20 Demetriades, A., "Turbulence Measurements in an Axisymmetric Compressible Wake," Tech. Rept. Pub. UG-4118, Aug. 1967, Philco-Ford Corp. 21 Becker, H. A., Hottel, A. C., and Williams, G. C., "The Nozzle-fluid Concentration Field of the Round, Turbulent, Free Jet," Journal of Fluid Mechanics, Vol. 30, No. 2, 1967, pp. 285303.
AN ALGEBRAIC EXTENSION OF THE MACMAHON MASTER THEOREM

We present a new algebraic extension of the classical MacMahon Master Theorem. The basis of our extension is the Koszul duality for non-quadratic algebras defined by Berger. Combinatorial implications are also discussed.
Dynamics of N=2 supersymmetric gauge theories in three-dimensions

We study the structure of the moduli spaces of vacua and superpotentials of N = 2 supersymmetric gauge theories in three dimensions. By analyzing the instanton corrections, we compute the exact superpotentials and determine the quantum Coulomb and Higgs branches of the theories in the weak coupling regions. We find candidates for non-trivial N = 2 superconformal field theories at the singularities of the moduli spaces. The analysis is carried out explicitly for gauge groups U(Nc) and SU(Nc) with N f flavors. We show that the field theory results are in complete agreement with the intersecting branes picture. We also compute the exact superpotentials for arbitrary gauge groups and arbitrary matter content.
Velocity centroids as tracers of the turbulent velocity statistics

We use the results of magnetohydrodynamic (MHD) simulations to emulate spectroscopic observations and use maps of centroids to study their statistics. In order to assess under which circumstances the scaling properties of the velocity field can be retrieved from velocity centroids, we compare two-point statistics (structure functions and power spectra) of velocity centroids with those of the underlying velocity field and analytic predictions presented by us in a previous paper. We tested a criterion for recovering velocity spectral index from velocity centroids derived in our previous work and propose an approximation of the early criterion using only the variances of unnormalized velocity centroids and column density maps. It was found that both criteria are necessary, but not sufficient, to determine if the centroids recover velocity statistics. Both criteria are well fulfilled for subsonic turbulence. We find that for supersonic turbulence with sonic Mach numbers s 2.5, centroids fail to trace the spectral index of velocity. Asymptotically, however, we claim that recovery of velocity statistics is always possible provided that the density spectrum is steep and the observed inertial range is sufficiently extended. In addition, we show that velocity centroids are useful for anisotropy studies and determining the direction of the magnetic field, even if the turbulence is highly supersonic, but only if it is sub-Alfvenic. This provides a tool for mapping the magnetic field direction and for testing whether the turbulence is sub-Alfvenic or super-Alfvenic.
The hydrogen coma of Comet Halley before perihelion: Preliminary observations with dynamics Explorer 1

The hydrogen coma of Comet Halley has been observed in resonantly scattered solar Lyman-alpha radiation during the period 1-29 January 1986 as the comet approached perihelion. These observations were obtained with the imaging photometer for vacuum-ultraviolet wavelengths on the spacecraft Dynamics Explorer 1. For the initial analysis of observations available in 17 orbits distributed throughout the period, least-squares fits are computed for the observed exponential decrease in brightness with radial distance from the nucleus. Brightness at the nucleus increased from approx. 3 to 17 kR during the observing period. Preliminary analysis yields water production rates of approx. 3.6 x 10 to the 29th power and 1.9 x 10 to the 30th power molecules/sec on 1 and 29 January, respectively.
Strategies for Control of Lattice Architecture in Low-Dimensional Molecular Metals: Assembly of Partially Oxidized Face-to-Face Linked Arrays of Metallomacrocycles

Abstract This paper discusses an approach to control molecular stacking interactions in low-dimensional mixed valence materials by locking partially oxidized metallomacrocycles together in a face-to-face orientation. Thus, doping of the cofacially linked oligomers [M(Pc)0]n (M = Si, Ge, Sn; Pc = phthalocyaninato) with halogen (I2, Br2) or quinone (e.g., TCNQ, DDQ) electron acceptors produces robust, electrically conductive polymers with a wide range of stoichiometrics and properties. The new materials have been studied by a variety of physical methods including X-ray diffraction, resonance Raman and infrared spectroscopy, ESR, static magnetic susceptibility, and variable-temperature four-probe electrical conductivity. Evidence is presented that some of the polymers have “metal-like” conductivity in the stacking direction and that transport properties within the series can be readily manipulated by rational variation of lattice architecture (e.g., the identity of the metal, M) and acceptor characteristics....
Quantum tomography of the full hyperfine manifold of atomic spins via continuous measurement on an ensemble

Quantum state reconstruction based on weak continuous measurement has the advantage of being fast, accurate and almost non-perturbative. In this work we present a pedagogical review of the protocol proposed by Silberfarb et al (2005 Phys. Rev. Lett. 95 030402), whereby an ensemble of identically prepared systems is collectively probed and controlled in a time-dependent manner so as to create an informationally complete continuous measurement record. The measurement history is then inverted to determine the state at the initial time through a maximum-likelihood estimate. The general formalism is applied to the case of reconstruction of the quantum state encoded in the magnetic sublevels of a large-spin alkali atom, 133Cs. We detail two different protocols for control. Using magnetic interactions and a quadratic ac Stark shift, we can reconstruct a chosen hyperfine manifold F, e.g. the seven-dimensional F = 3 manifold in the electronic ground state of Cs. We review the procedure as implemented in experiments (Smith et al 2006 Phys. Rev. Lett. 97 180403). We extend the protocol to the more ambitious case of reconstruction of states in the full 16-dimensional electronic ground subspace (F = 3⊕F = 4), controlled by microwaves and radio-frequency (RF) magnetic fields. We give detailed derivations of all physical interactions, approximations, numerical methods and fitting procedures, tailored to the realistic experimental setting. For the case of light-shift and magnetic control, reconstruction fidelities of ~0.95 have been achieved, limited primarily by inhomogeneities in the light-shift. For the case of microwave/RF-control we simulate fidelity >0.97, limited primarily by signal-to-noise.
Electrical conductivity measurements in a Faraday accelerator.

Abstract : The paper discusses the results of an experimental study of a potassium seeded-argon atmospheric pressure Faraday accelerator. Electrical conductivity, with and without applied magnetic field, temperature of the electrodes, and potential distributions across the channel were measured. The channel was approximately 1 cm x 1 cm x 10 cm long and consisted of continuous Ta electrodes and BN sidewalls. The potential distributions across the channel, measured by means of Ta wires embedded in the sidewalls, show very large wall sheaths. Since the electrode temperatures are sufficiently high to give good thermionic emission, these large sheath voltage drops indicate the presence of thick boundary layers of low electrical conductivity. In the presence of a transverse magnetic field the measurements show that the boundary layers become thinner, as predicted by theory. The values of conductivity measured across the central core of the flow are compared with predictions of Kerrebrock's two-temperature theory, and the agreement between the measured and calculated values is good. These are probably the first conductivity measurements to be reported on an atmospheric pressure, supersonic gas flow with applied magnetic field. (Author)
Synthetic Routes to Pyrroloiminoquinone Alkaloids. A Direct Synthesis of Makaluvamine C

Makaluvamine C is a pyrroloiminoquinone which has been isolated from marine sponges. This molecule has been synthesized in 13 steps from p-anisidine. The key steps in this synthesis include an intramolecular nucleophilic aromatic substitution mediated by potassium tert-butoxide, the selective reduction of a dinitro ester using catalytic hydrogenation, and the novel use of Fremy's salt to synthesize an iminoquinone from an amino phenol. The synthesis of makaluvamine C has been achieved from p-anisidine in 13.1% overall yield.
Software-directed power-aware interconnection networks

Interconnection networks have been deployed as the communication fabric in a wide spectrum of parallel computer systems, ranging from chip multiprocessors (CMPs) and embedded multicore systems-on-a-chip (SoCs) to clusters and server blades. Recent technology trends have permitted a rapid growth of chip resources, faster clock rates, and wider communication bandwidths, however, these trends have also led to an increase in power consumption that is becoming a key limiting factor in the design of such scalable interconnected systems. Power-aware networks, therefore, need to become inherent components of single and multi-chip parallel systems. In the hardware arena, recent interconnection network power-management research work has employed limited-scope techniques that mostly focus on reducing the power consumed by the network communication links. As these limited-scope techniques are not tailored to the applications running on the network, power savings and the corresponding impact on network latency vary significantly from one application to the next as we demonstrate in this paper; in many cases, network performance can severely suffer. In the software arena, extensive research on compile-time optimizations has produced parallelizing compilers that can efficiently map an application onto hardware for high performance. However, research into power-aware parallelizing compilers is in its infancy. In this paper, we take the first steps toward tailoring applications' communication needs at run-time for low power. We propose software techniques that extend the flow of a parallelizing compiler in order to direct run-time network power reduction. We target network links, a significant power consumer in these systems, allowing dynamic voltage scaling (DVS) instructions extracted during static compilation to orchestrate link voltage and frequency transitions for power savings during application run-time. Concurrently, an online hardware mechanism measures network congestion levels and adapts these off-line DVS settings to maximize network performance. Our simulations over three existing parallel systems, ranging from very fine-grained single-chip to coarse-grained multi-chip architectures, show that link power consumption can be reduced by up to 76.3p, with a minor increase in latency, ranging from 0.18 to 6.78p across a number of benchmark suites.
Stationarity of magnetohydrodynamic fluctuations in the solar wind

Solar wind research and studies of charged particle propagation often assume that the interplanetary magnetic field represents a stationary random process. The extent to which ensemble averages of the solar wind magnetic fields follow the asymptotic behavior predicted by the ergodic theorem was investigated. Several time periods, including a span of nearly two years, are analyzed. Data intervals which span many solar rotations satisfy the conditions of weak stationarity if the effects of solar rotation are included in the asymptotic analysis. Shorter intervals which include a small integral number of interplanetary sectors also satisfy weak stationarity. The results are illustrated using magnetometer data from the ISEE-3, Voyager and IMP spacecraft.