cssi/SciSciGPT-SciSciNet huggingface dataset:
Synergistic prevention of biofouling in seawater desalination by zwitterionic surfaces and low-level chlorination.

Water scarcity affects one in three people in the world.[1] With nearly 98% of the world's available water supply being seawater or brackish water, desalination has become an important means to address the scarcity of freshwater resources. Thin film composite (TFC) reverse osmosis (RO) membranes enable the removal of salt ions from seawater at room temperature by applying pressure to the seawater feed. TFC-RO has quickly become the dominating desalination method since its commercialization in the 1980s and is now used in nearly all RO desalination plants.[2] TFC-RO is considered to have the greatest water permeability with high salt rejection rate.[2] The bottleneck of TFC-RO to produce freshwater via seawater desalination at a comparable price to natural freshwater is severe membrane fouling, which impairs water permeation and salt rejection and thus reduces freshwater yield. Currently, marine biota and in particular bacteria are removed from the feed by pretreatment, the most energy-intensive (responsible for >36% of total plant energy consumption) and chemical-intensive step in a desalination plant and one that poses environmental risks to marine organisms when treated water is discharged back into the ocean.[2] Fouling-resistant RO membranes would bring major improvements in energy usage, process reliability and lower the environmental impact of seawater desalination.
The cluster galaxy circular velocity function

We present galaxy circular velocity functions (GCVFs) for 34 low redshift (z < � 0.15) clusters identified in the Sloan Digital Sky Survey (SDSS), for fifteen clusters drawn from dark matter simulations of hierarchical structure growth in aCDM cosmology, and for �29,000 SDSS field galaxies. We find that the observed and simulated cluster GCVFs take the form of a power law. The cumulative GCVFs of the simulated clusters are very similar across a wide range of cluster masses, provided individual subhalo circular velocities are scaled by the circular velocities of the parent cluster. Once all sources of error are accounted for, the intrinsic scatter in the cumulative, scaled observed cluster GCVF is consistent with the simulations. The slope of the observed cluster GCVF is �-2.5, independent of cluster velocity dispersion. The average slope of the simulated GCVFs is somewhat steeper, although formally consistent given the errors. Using our highest resolution cluster, we find that the effects of baryons on galaxy rotation curves is to flatten the simulated cluster GCVF into better agreement with observations. Finally, we find that the field GCVF deviates significantly from a power law, being flatter than the cluster GCVF at circular velocities less than 200 kms 1 , and steeper at circular velocities greater than 200 kms 1 .
On the problem of uniform references to data structures

The cost of a change to a large software system is often primarily a function of the size of the system rather than the complexity of the change. One reason for this is that programs which access some given data structure must operate on it using notations which are determined by its exact representation. Thus, changing how it is implemented may necessitate changes to the programs which access it. This paper develops a programming language notation and semantic interpretations which allow a program to operate on a data object in a manner which is dependent only on its logical or abstract properties and independent of its underlying concrete representation.
Structural and compositional investigations of Zr4Pt2O: A filled-cubic Ti2Ni-type phase

Syntheses, structural and compositional analyses of the filled cubic Ti{sub 2}Ni-type phase in Zr-Pt-O system have been studied, largely for the platinum-richer compositions. Diffraction quality crystals were grown by annealing an arc-melted composition Zr{sub 4}Pt{sub 2}O{sub 0.66} at 1600 C under Ar. The refined composition Zr{sub 4.0}Pt{sub 1.95(1)}O{sub 0.93(6)} (a=12.5063(6) {angstrom}, Fd{bar 3}m, Z=16) is close to the idealized composition Zr{sub 4}Pt{sub 2}O known in several other Zr-T-O systems (T=late 4d or 5d transition element). (This composition has been erroneously reported by ICDD for years as Zr{sub 6}Pt{sub 3}O (No. 00-017-0557) and referred to as {epsilon}-Zr{sub 6}Pt{sub 3}O.) The product is only marginally poor in platinum and oxygen, in contrast to the 1960 reports of metallographic studies ({approx} Zr{sub 4}Pt{sub 1.62}O{sub 0.44}). Under arc-melting conditions, high yields of the cubic phase are obtained from samples with lower platinum concentrations (Zr{sub 4}Pt{sub 1.74}O{sub 1.04}), whereas samples near the refined cubic composition contain hexagonal Zr{sub 5}Pt{sub 3}O{sub x} as well (Mn{sub 5}Si{sub 3}-type). The hexagonal structure of binary Zr{sub 5}Pt{sub 3} was also refined (Mn{sub 5}Si{sub 3} type, P6{sub 3}/mcm, a=8.210(1) {angstrom}, c=5.385(2) {angstrom}) and shown to be non-stoichiometric to at least Zr{sub 5}Pt{sub 2.5}.
Labels for Non-Individuals?

Quasi-set theory is a first-order theory without identity, which allows us to cope with non-individuals in a sense. A weaker equivalence relation called “indistinguishability” is an extension of identity in the sense that if x is identical to y then x and y are indistinguishable, although the reciprocal is not always valid. The interesting point is that quasi-set theory provides us with a useful mathematical background for dealing with collections of indistinguishable elementary quantum particles. In the present paper, however, we show that even in quasi-set theory it is possible to label objects that are considered as non-individuals. This is the first paper of a series that will be dedicated to the philosophical and physical implications of our main mathematical result presented here.
Misalignment in Gas Foil Journal Bearings: An Experimental Study

As gas foil journal bearings become more prevalent in production machines, such as small gas turbine propulsion systems and microturbines, system-level performance issues must be identified and quantified in order to provide for successful design practices. Several examples of system-level design parameters that are not fully understood in foil bearing systems are thermal management schemes, alignment requirements, balance requirements, thrust load balancing, and others. In order to address some of these deficiencies and begin to develop guidelines, this paper presents a preliminary experimental investigation of the misalignment tolerance of gas foil journal bearing systems. Using a notional gas foil bearing supported rotor and a laser-based shaft alignment system, increasing levels of misalignment are imparted to the bearing supports while monitoring temperature at the bearing edges. The amount of misalignment that induces bearing failure is identified and compared to other conventional bearing types such as cylindrical roller bearings and angular contact ball bearings. Additionally, the dynamic response of the rotor indicates that the gas foil bearing force coefficients may be affected by misalignment.
Model reduction for flexible space structures

This paper presents the conditions under which modal truncation yields a near-optimal reduced-order model for a flexible structure. Next, a robust model reduction technique to cope with the damping uncertainties typical of flexible space structure is developed. Finally, a flexible truss and the COFS-1 structure are used to give realistic applications for the model reduction techniques studied in the paper.
Catalytic enantioselective formation of chiral-bridged dienes which are themselves ligands for enantioselective catalysis.

This paper reports a method for highly enantioselective Diels−Alder reaction with an acetylene equivalent to produce chiral-bridged dienes. These dienes, by coordination to Rh(I), can serve as catalysts for the enantioselective addition of vinyl or aryl groups to α,β-unsaturated ketones.
Epilepsy and driving in North Carolina: An exploratory study

Epileptic drivers offer a risk to the general driving population, both because of affected brain function and because of possible effects of medication. A 1982 pilot study examined the driving records of 112 persons using North Carolina Division of Health Services clinics for the treatment of epilepsy who also held a North Carolina driver's license. Of those undergoing treatment in the clinics, 26% were known by the Division of Motor Vehicles (DMV) to be epileptics. This group had a reported crash rate 1.4 times that of the general driving population, whereas the rate for epileptics not known to the DMV was 1.1 times the general rate. Epileptics with grand mal and temporal or psychomotor seizures accounted for all recorded crashes. Implications for highway safety administrators and for future research are discussed.
Security of quantum cryptography against individual attacks

An attempt to eavesdrop on a quantum cryptographic channel reveals itself through errors it inevitably introduces into the transmission. We investigate the relationship between the induced error rate and the maximum amount of information the eavesdropper can extract, in both the two-state B92 [B92 refers to the work of C. H. Bennett, Phys. Rev. Lett. 68, 3121 (1992)] and the four-state BB84 [BB84 refers to the work of C. H. Bennett and G. Brassard, in Proceedings of the IEEE International Conference on Computers, Systems, and Signal Processing, Bangalore, India (IEEE, New York, 1984), pp. 175--179] quantum cryptographic protocols. In each case, the optimal eavesdropping method that on average yields the most information for a given error rate is explicitly constructed. Analysis is limited to eavesdropping strategies where each bit of the quantum transmission is attacked individually and independently from other bits. Subject to this restriction, however, we believe that all attacks not forbidden by physical laws are covered. Unlike previous work, the eavesdropper's advantage is measured in terms of Renyi (rather than Shannon) information, and with respect only to bits received error-free by Bob (rather than all bits). This alters both the maximum extractable information and the optimal eavesdropping attack. The result can be used directly at the privacy amplification stage of the protocol to accomplish secure communication over a noisy channel.
Detection and Isolation of Failures in Directed Networks of LTI Systems

We propose a methodology to detect and isolate link failures in a weighted and directed network of identical multi-input multioutput linear time-invariant (LTI) systems when only the output responses of a subset of nodes are available. Our method is based on the observation of jump discontinuities in the output derivatives, which can be explicitly related to the occurrence of link failures. The order of the derivative at which the jump is observed is given by $r(d+1)$ , where $r$ is the relative degree of each system's transfer matrix, and $d$ denotes the distance from the location of the failure to the observation point. We then propose detection and isolation strategies based on this relation. Furthermore, we propose an efficient algorithm for sensor placement to detect and isolate any possible link failure using a small number of sensors. Available results from the theory of submodular set functions provide us with performance guarantees that bound the size of the chosen sensor set within a logarithmic factor of the smallest feasible set of sensors. These results are illustrated through elaborative examples and supplemented by computer experiments.
Self-assembly of amphiphiles with terthiophene and tripeptide segments into helical nanostructures

Abstract We previously reported a class of tripeptide amphiphiles known as peptide lipids that self-assemble into one-dimensional nanostructures with superhelical twisting. The pitch of this supramolecular twisting is controlled directly through sterics in the molecular structure of hydrophobic segments. In this work we study the supramolecular behavior of these nanoscale helices by substituting with a terthiophene conjugated segment of potential electronic interest and also through variations in the stereochemistry of the tripeptide. This terthiophene peptide lipid was shown to self-assemble into one-dimensional helical nanofibers with a regular diameter of 9±1 nm and helical pitch of 65±6 nm, and also found to form hierarchical double- and triple-stranded helices, which could be associated with terthiophene J-aggregate interactions among fibers. For stereochemical effects, we compared four diastereomers in the tripeptide sequence using l -glutamic acid and l - and d -alanine residues to probe their ability to control supramolecular organization. Interestingly, we found by atomic force microscopy that the LLD diastereomers formed cylindrical nanofibers without any twisting, whereas LDD diastereomeric segments self-assembled into helical nanofibers with a pitch of 40±6 nm. LDL diastereomeric segments formed, on the other hand, aggregates without any regular shape. We propose that these profound effects of chirality with amino acid sequence are related to changes in the β-sheet sub-structure within the nanofibers.
Compressible Dynamic Stall Control Using a Variable Droop Leading Edge Airfoil

The control of compressible dynamic stall using a variable droop leading edge airfoil is described. The leading 25% of a VR-12 airfoil is drooped as it executes sinusoidal pitch oscillations such that the leading portion of the airfoil is always at a low effective incidence to the flow. Airfoil performance data determined for freestream Mach numbers ranging from 0.2 to 0.4, at reduced frequencies from 0 to 0.1, and using unsteady pressure transducer measurements, show that droop reduces the tendency of the airfoil to enter the dynamic stall state. Even when it does, the strength of the dynamic stall vortex is significantly reduced, which is reflected in the 40 to 50% smaller negative peak pitching-moment values, with positive damping of the airfoil. Also, the airfoil drag when the droop is dynamically varied is reduced by up to 75% relative to a nondrooped airfoil, making a strong case for the use of this concept for dynamic stall control
Dechalcogenative allylic selenosulfide and disulfide rearrangements: complementary methods for the formation of allylic sulfides in the absence of electrophiles. Scope, limitations, and application to the functionalization of unprotected peptides in aqueous media.

Primary allylic selenosulfates (seleno Bunte salts) and selenocyanates transfer the allylic selenide moiety to thiols giving primary allylic selenosulfides, which undergo rearrangement in the presence of PPh3 with the loss of selenium to give allylically rearranged allyl alkyl sulfides. This rearrangement may be conducted with prenyl-type selenosulfides to give isoprenyl alkyl sulfides. Alkyl secondary and tertiary allylic disulfides, formed by sulfide transfer from allylic heteroaryl disulfides to thiols, undergo desulfurative allylic rearrangement on treatment with PPh3 in methanolic acetonitrile at room temperature. With nerolidyl alkyl disulfides this rearrangement provides an electrophile-free method for the introduction of the farnesyl chain onto thiols. Both rearrangements are compatible with the full range of functionality found in the proteinogenic amino acids, and it is demonstrated that the desulfurative rearrangement functions in aqueous media, enabling the derivatization of unprotected peptid...
Measuring and modeling the effects of G-3 exchange rate fluctuations on small open economies: A natural experiment

Abstract I present evidence that exchange rate fluctuations among the world's major currencies significantly affect the business cycles of small open economies. The impact of those fluctuations on any given country depends crucially on its exchange rate regime. The three Baltic countries in Central Europe constitute an interesting natural experiment in that regard. I estimate a structural vector autoregression (VAR) model to show the differential impact of euro–dollar exchange rate fluctuations on the business cycles of these three countries. Next, I build a dynamic sticky-price model and I calibrate it to the Baltic States in order to match and explain the empirical evidence.
Strength coefficients of the cubic criterion for graphite composites

On presente les methodes de determination des coefficients et de l'enveloppe de resistance mecanique du graphite dans un etat de contrainte biaxiale en reliant le critere de resistance cubique aux donnees experimentales. On presente un exemple numerique montrant que les resultats theoriques et experimentaux sont en bon accord
The 3-server problem in the plane

In the k-server problem we wish to minimize, in an online fashion, the movement cost of k servers in response to a sequence of requests (we assume that k ≥ 2). The request issued at each step is specified by a point r in a given metric space M. To serve this request, one of the k servers must move to r. It is known that if M has at least k + 1 points then no online algorithm for the k-server problem in M has competitive ratio smaller than k. The best known upper bound on the competitive ratio in arbitrary metric spaces, by Koutsoupias and Papadimitriou (J. ACM 42 (1995) 971), is 2k - 1. There are only a few special cases for which k-competitive algorithms are known: for k = 2, when M is a tree, or when M has at most k + 2 points. We prove that the Work Function Algorithm is 3-competitive for the 3-server problem in the Manhattan plane. As a corollary, we obtain a 4.243-competitive algorithm for 3 servers in the Euclidean plane. The best previously known competitive ratio for 3 servers in these metric spaces was 5.
Infiltration of Reaction-Bonded Silicon Nitride with Equilibrium Y-Si-O-N Melt

An equilibrium Y-Si-O-N melt was infiltrated to eliminate the open porosity of reaction-bonded silicon nitride at 1600--1800 C. This oxynitride melt contained two equilibrium phases, a [beta]-Si[sub 3]N[sub 4] solid phase and a liquid phase at high temperatures. Before infiltration, porous reaction-bonded silicon nitride compacts were heat-treated to completely transform to the [beta]-Si[sub 3]N[sub 4] phase. After infiltration, the flexural strength of the reaction-bonded silicon nitride material increased from 200 to 600 MPa at 25 C, from 200 to 300 MPa at 1400 C in air.
de novo asymmetric synthesis of daumone via a palladium-catalyzed glycosylation.

The enantioselective syntheses of daumone and two analogues have been achieved in seven to eight steps. This route relies upon a diasteroselective palladium-catalyzed glycosylation reaction for the formation of the anomeric bond. The asymmetry of the sugar and aglycone portion of daumone were introduced by Noyori reduction of an acylfuran and a propargyl ketone. A highly diastereoselective epoxidation and reductive ring opening established the desired C-2 and C-4 stereochemistry of daumone.
Vodka and wine consumption in a swine model of metabolic syndrome alters insulin signaling pathways in the liver and skeletal muscle

Background The purpose of this study was to examine the effects of alcohol in the context of metabolic syndrome on insulin signaling pathways in the liver and skeletal muscle. Methods Twenty-six Yorkshire swine were fed a hypercaloric, high-fat diet for 4 weeks then split into 3 groups: hypercholesterolemic diet alone (HCC, n = 9), hypercholesterolemic diet with vodka (HCVOD, n = 9), and hypercholesterolemic diet with wine (HCW, n = 8) for 7 weeks. Animals underwent intravenous dextrose challenge before euthanasia and tissue collection. Results HCC, HCVOD, and HCW groups had similar blood fasting glucose levels, liver function test, and body mass index. Thirty and 60 minutes after dextrose infusion, HCVOD and HCW groups had significantly increased blood glucose levels compared with the HCC group. The HCW group had significantly increased levels of insulin compared with the HCC group. Immunoblotting in skeletal muscle demonstrated that alcohol up-regulates p-IRS1, IRS2, AKT, AMPKα, PPARα, Fox01, and GLUT4. In the liver, HCW had up-regulation of AKT, AMPKα, and GLUT4 compared with HCC. Skeletal muscle immunohistochemistry demonstrated increased sarcolemmal expression of GLUT4 in both alcohol groups compared with HCC. Conclusion Moderate alcohol consumption in a swine model of metabolic syndrome worsens glucose metabolism by altering activation of the insulin signaling pathway in the liver and skeletal muscle.
Synthesis of tert-Alkyl Amino Hydroxy Carboxylic Esters via an Intermolecular Ene-Type Reaction of Oxazolones and Enol Ethers

tert-Alkyl amino hydroxy carboxylic acids are abundantly present within the structure of many biologically active natural products. We describe herein the synthesis of these substrates using an oxazolone-mediated ene-type reaction with enol ethers followed by NaBH4 reduction of the intermediate oxazolone.
Exergy Analysis of Combined Cycles: Part 1—Air-Cooled Brayton-Cycle Gas Turbines

Quantitative analytical tools based on the second law of thermodynamics provide insight into the complex optimization tradeoffs encountered in the design of a combined cycle. These tools are especially valuable when considering approaches beyond the existing body of experience, whether in cycle configuration or in gas turbine cooling technology. A framework for such analysis was provided by the author [1-3] using simplified, constant-property models. In this paper, this theme is developed to include actual chemical and thermodynamic properties as well as relevant practical design details reflecting current engineering practice. The second-law model is applied to calculate and provide a detailed breakdown of the sources of inefficiency of a combined cycle. Stage-by-stage turbine cooling flow and loss analysis calculations are performed using the GASCAN program and examples of the resulting loss breakdowns presented. It is shown that the dominant interaction governing the variation of cycle efficiency with turbine inlet temperature is that between combustion irreversibility and turbine cooling losses. Compressor and pressure-drop losses are shown to be relatively small. A detailed analysis and loss breakdown of the steam bottoming cycle is presented in Part 2 of this paper.
Real-time orbiter abort guidance

This paper describes a real-time abort guidance algorithm which determines the time sequence of the powered maneuvers and the orientation of the thrust vector throughout an abort-mission action initiated during the orbiter ascent phase. It involves guiding a heavily loaded Space Shuttle vehicle, passing through severe environmental conditions, back to a designated landing area. A graphical example and estimates of the computer requirements are included.
Fast Byzantine Consensus

We present the first protocol that reaches asynchronous Byzantine consensus in two communication steps in the common case. We prove that our protocol is optimal in terms of both number of communication steps and number of processes for two-step consensus. The protocol can be used to build a replicated state machine that requires only three communication steps per request in the common case. Further, we show a parameterized version of the protocol that is safe despite f Byzantine failures and, in the common case, guarantees two-step execution despite some number t of failures (t les f). We show that this parameterized two-step consensus protocol is also optimal in terms of both number of communication steps and number of processes
An interpersonal multimedia visualization system

Media View, a system that can be used to produce an electronic document containing mathematics, data sets, and associated visualizations, is discussed. Animations and other substructures persist through electronic mailing and can be awakened by the recipient. The features of Media View documents are described. Analysis and visualization with Media View are examined, including linking to Mathematica, producing locally derived animations, visualizing remotely produced data sets, and viewing video sequences. The architectural details of Media View are discussed. >
On the Optimality of the Patent Renewal System

The patent system is mainly a renewal system: the patent life is chosen by the patentee in return for fees. I ask whether such a system can be justified by asymmetric information on costs and benefits of research. In such a model I show that renewal mechanisms (possibly with subsidies) are equivalent to direct revelation mechanisms and therefore cannot be improved on, regardless of the objective function. Under plausible circumstances, patents should have a uniform life, rather than varying in length, as typically occurs under a renewal system.
Exact four-dimensional dyonic black holes and Bertotti-Robinson spacetimes in string theory

Conformal field theories corresponding to two-dimensional electrically charged black holes and to two-dimensional anti-de Sitter space with a covariantly constant electric field are simply constructed as SL(2,R)/Z Wess-Zumino-Witten coset models. Four-dimensional spacetime solutions are obtained by tensoring these two-dimensional theories with $\frac{\mathrm{SU}(2)}{Z(m)}$ coset models. These describe a family of dyonic black holes and the Bertotti-Robinson universe.
Earthquake Forecasting Using Hidden Markov Models

This paper develops a novel method, based on hidden Markov models, to forecast earthquakes and applies the method to mainshock seismic activity in southern California and western Nevada. The forecasts are of the probability of a mainshock within 1, 5, and 10 days in the entire study region or in specific subregions and are based on the observations available at the forecast time, namely the interevent times and locations of the previous mainshocks and the elapsed time since the most recent one. Hidden Markov models have been applied to many problems, including earthquake classification; this is the first application to earthquake forecasting.
Cosmology with interacting dark energy

The early cosmic inflation, when taken along with the recent observations that the universe is currently dominated by a low density vacuum energy, leads to at least two potential problems which modern cosmology must address. First, there is the old cosmological constant problem, with a new twist: the coincidence problem. Secondly, cosmology still lacks a model to predict the observed current cosmic acceleration and to determine whether or not there is a future exit out of this state (as previously in the inflationary case). This constitutes (what is called here) a dynamical problem. Here a framework is proposed to address these two problems, based on treating the cosmic background vacuum (dark) energy as both dynamical and interacting. The universe behaves as a vacuum-driven cosmic engine which, in search of equilibrium, always back-reacts to vacuum-induced accelerations by increasing its inertia (internal energy) through vacuum energy dissipation. The process couples cosmic vacuum (dark) energy to matter to produce future-directed increasingly comparable amplitudes in these fields by setting up oscillations in the decaying vacuum energy density and corresponding sympathetic ones in the matter fields. By putting bounds on the relative magnitudes of these coupled oscillations the model offers a natural and conceptually simple channel to discuss the coincidence problem, while also suggesting a way to deal with the dynamical problem. A result with important observational implications is an equation of state w(t) which specifically predicts a variable, quasi-periodic, acceleration for the current universe. This result can be directly tested by future observational techniques such as SNAP.
Branching ratios and CP asymmetries of B decays to a vector and a pseudoscalar meson

Abstract We consider two body decays of B meson into a light vector (V) and a pseudoscalar (P) meson. The constraint obtained from the B→P P modes on the parameter space of the input parameters is imposed also on B→V P modes. In particular we constrain ξ≡(1/Nc) for those modes from recently measured B→ωK, φK and are able to get a satisfactory pictures for all modes where data exists. Modes that should be seen shortly and those with possibly large CP asymmetries are identified.
A network-patch methodology for adapting agent-based models for directly transmitted disease to mosquito-borne disease.

Mosquito-borne diseases cause significant public health burden and are widely re-emerging or emerging. Understanding, predicting, and mitigating the spread of mosquito-borne disease in diverse populations and geographies are ongoing modelling challenges. We propose a hybrid network-patch model for the spread of mosquito-borne pathogens that accounts for individual movement through mosquito habitats, extending the capabilities of existing agent-based models (ABMs) to include vector-borne diseases. The ABM are coupled with differential equations representing ‘clouds’ of mosquitoes in patches accounting for mosquito ecology. We adapted an ABM for humans using this method and investigated the importance of heterogeneity in pathogen spread, motivating the utility of models of individual behaviour. We observed that the final epidemic size is greater in patch models with a high risk patch frequently visited than in a homogeneous model. Our hybrid model quantifies the importance of the heterogeneity in the spread...
Shape-Dependent Oriented Trapping and Scaffolding of Plasmonic Nanoparticles by Topological Defects for Self-Assembly of Colloidal Dimers in Liquid Crystals

We demonstrate scaffolding of plasmonic nanoparticles by topological defects induced by colloidal microspheres to match their surface boundary conditions with a uniform far-field alignment in a liquid crystal host. Displacing energetically costly liquid crystal regions of reduced order, anisotropic nanoparticles with concave or convex shapes not only stably localize in defects but also self-orient with respect to the microsphere surface. Using laser tweezers, we manipulate the ensuing nanoparticle-microsphere colloidal dimers, probing the strength of elastic binding and demonstrating self-assembly of hierarchical colloidal superstructures such as chains and arrays.
Parity, circuits and the polynomial time hierarchy

A super-polynomial lower bound is given for the size of circuits of fixed depth computing the parity function. Introducing the notion of polynomial-size, constant-depth reduction, similar results are shown for the majority, multiplication, and transitive closure functions. Connections are given to the theory of programmable logic arrays and to the relativization of the polynomial-time hierarchy.
Symmetrical ring cleavage of the gold(I) phosphorus ylide dimer [Au(CH2)2PPh2]2 by hydrogen halides in toluene

Abstract The reaction of the cyclic, 8-membered gold(I) ylide dimer, bis [μ-(dimethylenediphenylphosphoranyl-C,C)]-digold(I), [Au(CH2)2PPh2]2, with two moles of HX (X = Cl, Br) in toluene yields the symmetric cleavage product halo(methylmethylenediphenylphosphoranyl)-gold(I), XAuCH2PPh2- (CH3), as the only isolable gold containing product. Further addition of HX affords a dimethyldiphenylphosphonium dihaloaurate(I) salt.
Stable cohomology over local rings

Abstract For a commutative noetherian ring R with residue field k stable cohomology modules Ext ˆ R n ( k , k ) have been defined for each n ∈ Z , but their meaning has remained elusive. It is proved that the k -rank of any Ext ˆ R n ( k , k ) characterizes important properties of R , such as being regular, complete intersection, or Gorenstein. These numerical characterizations are based on results concerning the structure of Z -graded k -algebra carried by stable cohomology. It is shown that in many cases it is determined by absolute cohomology through a canonical homomorphism of algebras Ext R ( k , k ) → Ext ˆ R ( k , k ) . Some techniques developed in the paper are applicable to the study of stable cohomology functors over general associative rings.
Generation of parallel electric fields in the Jupiter–Io torus wake region

Infrared and ultraviolet images have established that auroral emissions at Jupiter caused by the electromagnetic interaction with Io not only produce a bright spot, but an emission trail that extends in longitude from Io's magnetic footprint. Electron acceleration that produces the bright spot is believed to be dominated by Alfven waves whereas we argue that the trail or wake aurora results from quasi-static parallel electric fields associated with large-scale, field-aligned currents between the Io torus and Jupiter's ionosphere. These currents ultimately transfer angular momentum from Jupiter to the Io torus. We examine the generation and the impact of the quasi-static parallel electric fields in the Io trail aurora. A critical component to our analysis is a current-voltage relation that accounts for the low-density plasma along the magnetic flux tubes that connect the Io torus and Jupiter. This low-density region, ∼2 Rj from Jupiter's center, can significantly limit the field-aligned current, essentially acting as a "high-latitude current choke." Once parallel electric fields are introduced, the governing equations that couple Jupiter's ionosphere to the Io torus become nonlinear and, while the large-scale behavior is similar to that expected with no parallel electric field, there are substantial deviations on smaller scales. The solutions, bound by properties of the Io torus and Jupiter's ionosphere, indicate that the parallel potentials are on the order of 1 kV when constrained by peak energy fluxes of a few milliwatts per square meter. The parallel potentials that we predict are significantly lower than earlier reports.
Emergency medical services via inland waterways

As emergency managers prepare contingency plans for incident response, it is important to recognize the resource offered by the nation’s inland waterways. This research investigates the feasibility of using inland waterway transportation to provide emergency medical response to catastrophic incidents. For many communities, inland waterways can provide medical services and equipment when other modes of transportation are inaccessible because of capacity overload or destruction. Our research objective is to develop a feasibility index to measure the potential of a given community to benefit from inland waterway-based emergency medical services. The Waterway Emergency Medical Service (WEMS) feasibility index guides emergency managers in evaluating the feasibility of incorporating emergency medical services via inland waterways into their emergency operations planning. A demonstration of the WEMS index on the state of Arkansas is presented.
N-propargyl-2-alkynylbenzothiazolium aza-enediynes: role of the 2-alkynylbenzothiazolium functionality in DNA cleavage.

Abstract The 2-alkynylbenzothiazolium salts 3a – d incorporating an N -propargyl moiety have been prepared as aza-enediyne analogues. While these aza-enediynes are shown to be modest DNA cleavage agents, DNA cleavage was also observed with the N -methyl-2-alkynylbenzothiazolium salt 4 , which lacks the aza-enediyne moiety. The structural requirements for DNA cleavage, and the correlation of DNA cleavage efficiency with the propensity of these compounds to undergo nucleophilic addition by methanol support a proposed DNA cleavage mechanism involving DNA alkylation by appropriate 2-alkynyl-substituted benzothiazolium salts.
Extreme value analysis for evaluating ozone control strategies

Tropospheric ozone is one of six criteria pollutants regulated by the US EPA, and has been linked to respiratory and cardiovascular endpoints and adverse effects on vegetation and ecosystems. Regional photochemical models have been developed to study the impacts of emission reductions on ozone levels. The standard approach is to run the deterministic model under new emission levels and attribute the change in ozone concentration to the emission control strategy. However, running the deterministic model requires substantial computing time, and this approach does not provide a measure of uncertainty for the change in ozone levels. Recently, a reduced form model (RFM) has been proposed to approximate the complex model as a simple function of a few relevant inputs. In this paper, we develop a new statistical approach to make full use of the RFM to study the effects of various control strategies on the probability and magnitude of extreme ozone events. We fuse the model output with monitoring data to calibrate the RFM by modeling the conditional distribution of monitoring data given the RFM using a combination of flexible semiparametric quantile regression for the center of the distribution where data are abundant and a parametric extreme value distribution for the tail where data are sparse. Selected parameters in the conditional distribution are allowed to vary by the RFM value and the spatial location. Also, due to the simplicity of the RFM, we are able to embed the RFM in our Bayesian hierarchical framework to obtain a full posterior for the model input parameters, and propagate this uncertainty to the estimation of the effects of the control strategies. We use the new framework to evaluate three potential control strategies, and find that reducing mobile-source emissions has a larger impact than reducing point-source emissions or a combination of several emission sources.
The classification of Toroidal Dehn surgeries on Montesinos knots

Exceptional Dehn surgeries have been classified for 2-bridge knots and Montesinos knots of length at least 4. In this paper we classify all toroidal Dehn surgeries on Montesinos knots of length 3.
A large-capacity drum-file memory system

Synopsis: The magnetic drum-file memory system described in this paper was designed for the Univac-Larc computing system as storage that would be intermediate in speed and in capacity between the Uniservo magnetic tapes and the ultra high-speed magnetic-core memory. Although designed for Univac-Larc, the drum-file memory system may be used for any type of systematic data processing where extremely short access time is not required and economy is an important consideration. Economy is achieved through the use of a single flying head, which can move parallel to the axis of the drum and perform the read-write operations for the entire drum. This arrangement eliminates the need for close mechanical tolerances and elaborate switching devices. The drum-file memory may also be used as a random-access device where a delay of a second or two is not critical, as, for example, in checking a particular item of an inventory.
Cell-like equivalences and boundaries of CAT(0) groups

In 2000, Croke and Kleiner showed that a CAT(0) group G can admit more than one boundary. This contrasted with the situation for δ-hyperbolic groups, where it was well-known that each such group admitted a unique boundary—in a very stong sense. Prior to Croke and Kleiner’s discovery, it had been observed by Geoghegan and Bestvina that a weaker sort of uniquness does hold for boundaries of torsion free CAT(0) groups; in particular, any two such boundaries always have the same shape. Hence, the boundary really does carry significant information about the group itself. In an attempt to strengthen the correspondence between group and boundary, Bestvina asked whether boundaries of CAT(0) groups are unique up to cell-like equivalence. For the types of space that arise as boundaries of CAT(0) groups, this is a notion that is weaker than topological equivalence and stronger than shape equivalence. In this paper we explore the Bestvina Cell-like Equivalence Question. We describe a straightforward strategy with the potential for providing a fully general positive answer. We apply that strategy to a number of test cases and show that it succeeds—often in unexpectedly interesting ways.
Consumer Inference: A Review of Processes, Bases, and Judgment Contexts

Because products are rarely described completely, consumers often form inferences that go beyond the information given. We review research on the processes, bases, and the judgment contexts in which inferences are formed. The most basic processes are induction (inferences from specific instances to general principles) versus deduction (inferences from general principles to specific instances). Stimulus-based inferences are formed on-line (as information is encountered) using situationally available information, whereas memory-based (or theory-based) inferences are formed using prior knowledge and experience. Inferences can pertain to a single product judged in isolation (a singular judgment context) or to multiple products considered in relation to one another (a comparative judgment context). This 2x2x2 (Induction vs. Deduction x Stimulus-Based vs. Memory-Based x Singular vs. Comparative Judgment) theoretical framework suggests that there are 8 different types of inferences that consumers may form. Based on this framework, we identify gaps in the literature and suggest directions for future research.
Time Variability in the X-Ray Nebula Powered by Pulsar B1509–58

We use new and archival Chandra and ROSAT data to study the time variability of the X-ray emission from the pulsar wind nebula (PWN) powered by PSR B1509−58 on timescales of one week to twelve years. There is variability in the size, number, and brightness of compact knots appearing within 20 ′′ of the pulsar, with at least one knot showing a possible outflow velocity of ∼ 0.6c (assuming a distance to the source of 5.2 kpc). The transient nature of these knots may indicate that they are produced by turbulence in the flows surrounding the pulsar. A previously identified prominent jet extending 12 pc to the southeast of the pulsar increased in brightness by 30% over 9 years; apparent outflow of material along this jet is observed with a velocity of ∼ 0.5c. However, outflow alone cannot account for the changes in the jet on such short timescales. Magnetohydrodynamic sausage or kink instabilities are feasible explanations for the jet variability with timescale of ∼ 1.3−2 years. An arc structure, located 30 ′′ −45 ′′ north of the pulsar, shows transverse structural variations and appears to have moved inward with a velocity of ∼ 0.03c over three years. The overall structure and brightness of the diffuse PWN exterior to this arc and excluding the jet has remained the same over the twelve year span. The photon indices of the diffuse PWN and possibly the jet steepen with increasing radius, likely indicating synchrotron cooling at X-ray energies.
Radial Temperature Profiles of 11 Clusters of Galaxies Observed with BEPPOSAX

We have derived azimuthally averaged radial temperature profiles of the X-ray gas contained within 11 clusters of galaxies with redshift z = 0.03-0.2 observed with BeppoSAX. Each of the 11 clusters have had their radial temperature profiles previously determined with ASCA. We find that the temperature profiles of these clusters are generally flat or increase slightly out to ~30% of the virial radius and that a decline in temperature of 14% out to 30% of the virial radius is ruled out at the 99% confidence level. This is in accordance with a previous ROSAT PSPC study and an ASCA study by White but in disagreement with an ASCA study by Markevitch et al. that found on average that cluster temperature profiles decreased significantly with radius.
Properties of metal oxide clusters in non-traditional oxidation states

Abstract Oxygen vacancies on metal oxide surfaces create active sites for catalytic processes, ranging from selective oxidation of alkenes to photocatalytic decomposition of water. Experimentally, there are numerous challenges associated with fully characterizing the role of oxygen vacancies in bulk systems. We present a bottom-up approach, probing the structures and electronic properties of small metal oxide clusters, and relating these properties to chemical reactivity. The work presented focuses on unary and binary Group 6 metal oxides (Mo and W) and their reactivity toward H 2 O and CO 2 . We additionally highlight more recent studies on binary Group 5/Group 6 metal oxides.
SERT II - Design requirements for integrating electric propulsion into a spacecraft

Electric propulsion systems integration into SERT 2 spacecraft, discussing launch imposed environment, thrust vector control, thrustor breakdown, power conditioning, etc
Effective Tools for Diagnosing Elusive Turbomachinery Dynamics Problems in the Field

The state of the art in measurement and signal processing techniques is discussed with reference to such factors as the directness of the measurement, the degree of intrusion required, the difficulty of installation, and the reliability or durability of the sensor. Problems addressed include rotating stall in the compressor section of a gas turbine, coupled lateral/torsional vibration in a gas turbine driven pipeline compressor, forced vibration of combustor parts, strain gage telemetry of blade vibrations, and nonintrusive measurement of blade vibrations using bearing-mounted accelerometers
Information equals amortized communication

We show how to efficiently simulate the sending of a single message M to a receiver who has partial information about the message, so that the expected number of bits communicated in the simulation is close to the amount of additional information that the message reveals to the receiver. This is a generalization and strengthening of the Slepian-Wolf theorem, which shows how to carry out such a simulation with low amortized communication in the case that M is a deterministic function of X. A caveat is that our simulation is interactive. As a consequence, we prove that the internal information cost (namely the information revealed to the parties) involved in computing any relation or function using a two party interactive protocol is exactly equal to the amortized communication complexity of computing independent copies of the same relation or function. We also show that the only way to prove a strong direct sum theorem for randomized communication complexity is by solving a particular variant of the pointer jumping problem that we define. This paper implies that a strong direct sum theorem for communication complexity holds if and only if efficient compression of communication protocols is possible. In particular, together with our result, a recent result of Ganor, Kol, and Raz implies that the strongest version of direct sum for randomized communication complexity is false.
Re-Evaluating the Nucleophilicity of Zinc Enolates in Alkylation Reactions†

The use of toluene allows for allylic and benzylic alkylation of zinc enolates, derived from an asymmetric copper-catalyzed conjugate addition of dialkylzinc, using a range of valuable electrophiles. The one-pot procedure avoids the use of additional transition-metal catalysts and does not require highly activated electrophiles.
The thermodynamic properties of the five benzoquinolines

Abstract Measurements leading to the calculation of the standard thermodynamic properties in the gas phase for acridine, phenanthridine, and 7,8-benzoquinoline are reported. Thermochemical and thermophysical properties were determined by adiabatic heat-capacity calorimetry, comparative ebulliometry, inclined-piston manometry, and combustion calorimetry. Comparisons with literature values are presented and discussed. Results were used to calculate standard entropies, enthalpies, and Gibbs free energies of formation at selected temperatures to 500 K. Group-contribution methods were used to estimate the standard gas-phase entropy and enthalpy of formation at 400 K for the remaining two benzoquinolines: 5,6-benzoquinoline and 6,7-benzoquinoline. The relative stabilities of the compounds and comparisons with hydrocarbon analogues are discussed. A reaction scheme for the formation of the benzoquinolines is outlined and the mole fractions of the isomers are estimated for the reactions proceeding under thermodynamic control.