cssi/SciSciGPT-SciSciNet huggingface dataset:
Integrating Catalytic Coal Gasifiers With Solid Oxide Fuel Cells

A review was conducted for coal gasification technologies that integrate with solid oxide fuel cells (SOFC) to achieve system efficiencies near 60% while capturing and sequestering >90% of the carbon dioxide [1–2]. The overall system efficiency can reach 60% when a) the coal gasifier produces a syngas with a methane composition of roughly 25% on a dry volume basis, b) the carbon dioxide is separated from the methane-rich synthesis gas, c) the methane-rich syngas is sent to a SOFC, and d) the off-gases from the SOFC are recycled back to coal gasifier. The thermodynamics of this process will be reviewed and compared to conventional processes in order to highlight where available work (i.e. exergy) is lost in entrained-flow, high-temperature gasification, and where exergy is lost in hydrogen oxidation within the SOFC. The main advantage of steam gasification of coal to methane and carbon dioxide is that the amount of exergy consumed in the gasifier is small compared to conventional, high-temperature, oxygen-blown gasifiers. However, the goal of limiting the amount of exergy destruction in the gasifier has the effect of limiting the rates of chemical reactions. Thus, one of the main advantages of steam gasification leads to one of its main problems: slow reaction kinetics. While conventional entrained-flow, high-temperature gasifiers consume a sizable portion of the available work in the coal oxidation, the consumed exergy speeds up the rates of reactions. And while the rates of steam gasification reactions can be increased through the use of catalysts, only a few catalysts can meet cost requirements because there is often significant deactivation due to chemical reactions between the inorganic species in the coal and the catalyst. Previous research into increasing the kinetics of steam gasification will be reviewed. The goal of this paper is to highlight both the challenges and advantages of integrating catalytic coal gasifiers with SOFCs.Copyright © 2010 by ASME
Merger Announcements and Trading

We test whether an increase either in informed trades or in large liquidity trades leads to greater correlation of trading volume across markets. We confirm that both trading volume and positive returns of target companies are abnormally high before merger announcements. We find a statistically significant increase in the correlation between New York Stock Exchange and Nasdaq/regional trading volume before merger announcements. Furthermore, after merger announcements, we find evidence of both large liquidity trading and a statistically significant increase in the correlation of trading volume across markets.
Competition for Trophies Triggers Male Generosity

Background Cooperation is indispensable in human societies, and much progress has been made towards understanding human pro-social decisions. Formal incentives, such as punishment, are suggested as potential effective approaches despite the fact that punishment can crowd out intrinsic motives for cooperation and detrimentally impact efficiency. At the same time, evolutionary biologists have long recognized that cooperation, especially food sharing, is typically efficiently organized in groups living on wild foods, even absent formal economic incentives. Despite its evident importance, the source of this voluntary compliance remains largely uninformed. Drawing on costly signaling theory, and in light of the widely established competitive nature of males, we hypothesize that unique and displayable rewards (trophies) out of competition may trigger male generosity in competitive social environments. Principal Findings Here, we use a controlled laboratory experiment to show that cooperation is sustained in a generosity competition with trophy rewards, but breaks down in the same environment with equally valuable but non-unique and non-displayable rewards. Further, we find that males' competition for trophies is the driving force behind treatment differences. In contrast, it appears that female competitiveness is not modulated by trophy rewards. Significance Our results suggest new approaches to promoting cooperation in human groups that, unlike punishment mechanisms, do not sacrifice efficiency. This could have important implications in any domain where voluntary compliance matters — including relations between spouses, employers and employees, market transactions, and conformity to legal standards.
Open Problems in Chemical Topology

The historical origins of chemical topology are highlighted and seven open problems in the discipline are defined. The current state of experimental work towards their solutions is reviewed. Open problems discussed include size and tightness limits on molecular knots, synthesis of knots more complex than the trefoil, measurement of the enantiomerization barrier of a topological rubber glove, and syntheses of a polyethylene trefoil knot, a stable open knot with stoppers, and a molecular Whitehead link.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Simulation study on breakdown behavior of field-plate SiC MESFETs

The effects of field-plate structures on SiC MESFETs were investigated using two-dimensional simulations. The simulation results without a field-plate were in good agreement with the characteristics of fabricated SiC MESFETs. The breakdown voltage was increased by 80 % when the optimum field-plate was applied to the device with a 0.5 /spl mu/m long gate and a 1 /spl mu/m spacing between gate and drain; a breakdown voltage of 240-250 V was obtained from a 0.35 /spl mu/m field-plate, while 140 V was obtained without a field-plate.
Intramolecular vs. intermolecular alkyl C-H bond activation. Complete thermodynamic and kinetic parameters for a reversible cyclometalation

Etude de la cyclisation du (bis-trimethylsilylmethyl di-η 5 -pentamethylcyclopentadienyl) thorium
Supergravity coupled to chiral and Yang-Mills matter at one loop

Abstract We present the full result for the divergent one-loop contribution to the effective boson Lagrangian for supergravity coupled to chiral and Yang-Mills supermultiplets. We also consider the specific case of dilaton couplings in effective supergravity Lagrangians from superstrings, for which the one-loop result is considerably simplified.
Exceptional superconformal algebras

Abstract Reductive W-algebras which are generated by bosonic fields of spin 1, a single spin-2 field and fermionic fields of spin - 3 2 are classified. Three new cases are found: a “symplectic” family of superconformal algebras which are extended by su(2)⊗sp(n), an N = 7 and an N = 8 superconformal algebra. The exceptional cases can be viewed as arising a Drinfeld-Sokolov type reduction of the exceptional Lie superalgebras F(4) and G(3), and have an octonionic description. The quantum versions of the superconformal algebras are constructed explicitly in all three cases.
Interventional cardiac catheterization in congenital heart disease

Cardiac catheterization has proved its value as a major tool in the diagnosis of congenital cardiac defects. The advent of non-invasive imaging of various sorts has altered the role of diagnostic catheterization. Within the past two decades cardiac catheter instruments to provide therapy have been applied to many lesions. Improvements in design and methods will expand the use of therapeutic catheterization. It is inevitable that better results will be obtained for those defects currently being treated that way, and that the method will be applied to other conditions.
Recent Advances in the Stereoselective Synthesis of Tetrahydrofurans.

Substituted tetrahydrofurans are commonly occurring substructures found in a broad array of natural products and other biologically active molecules. For example, the annonaceous acetogenins are a large family of natural products bearing tetrahydrofuran cores.1 Tetrahydrofuran moieties are also found in many other classes of natural products including lignans,2 polyether ionophores3 and macrodiolides.4 These substances exhibit a diverse range of biological activities including antitumor, antihelmic, antimalarial, antimicrobial, and antiprotozoal. Due to the importance of these molecules, considerable effort has been devoted towards the development of methods for the stereoselective construction of substituted tetrahydrofurans.5 This review covers the important transformations that have been used in the stereoselective synthesis of tetrahydrofurans, with emphasis placed on literature published between 1993–2005. A broad array of new methods developed over the past twelve years are described, as well as recent advances in older reactions that are widely used. The coverage of this review is limited to the synthesis of tetrahydrofurans; methods that generate furans, dihydrofurans, and benzofurans are not discussed.
Modified Optical Bloch Equations for Solids

In a recent experiment of DeVoe and Brewer [1], it was concluded that the optical Bloch equations are incapable of describing the saturation phenomena observed. Optical free induction decay (FID) measurements of the impurity ion crystal Pr3+:LaF3 were conducted where the Pr3+ ions are coherently prepared by a laser field under steady-state conditions and then freely precess when the driving field is removed. At low optical fields, the observed Pr3+ optical linewidth is dominated by magnetic fluctuations arising from pairs of fluorine nuclear flip-flops. At high optical fields, this nuclear broadening mechanism is quenched and the Bloch equations are seriously violated. On physical grounds, this failure is due to a time-averaging of the magnetic interaction as the optical nutation frequency increases [2]. The phenomenological dipole dephasing time T2 of the Bloch equations is therefore not a true constant but lengthens with increasing field strength.
State vectors in higher-dimensional gravity with kinematic quantum numbers of quarks and leptons

Abstract We examine the question of whether fundamental fermions can be regarded as topological solitons (geons) of a theory of pure quantum gravity in n + 4 dimensions. In particular, we consider the quantum gravitational field for (n + 4)-dimensional space-times which have asymptotic Kaluza-Klein behavior: asymptotic topology of the form R4 × G/H and a metric that is asymptotically the direct sum of the Minkowski metric on R4 and the natural symmetric metric on G/H. We argue that if there is a nonsingular theory of pure quantum gravity (a theory that, below Planck energy, involves only the space-time metric), then there are stable ground states with the kinematical quantum numbers of fundamental fermions: that is, states which have spin 1 2 and belong to the fundamental representation of G . Multi-valued representations of the asymptotic symmetry group can arise from diffeomorphisms (diffeos) of the (n + 3)-dimensional space that are not isotopic to the identity. In a path integral approach, the creation of fundamental fermions (topological geons) requires a space-time in which the topology of space-like hypersurfaces changes and in which the relevant diffeos on the final (n + 3)-space (containing the geons) are not extendible to diffeos of the (n + 4)-space-time. We prove that such pair-creation geometries occur in a lorentzian as well as euclidean framework and that the diffeos are not extendible. Although zero-mass modes of finite-size fermions need not belong to a real representation of the internal group, it is not difficult to prove that, independent of the fermion size, one cannot avoid mirror fermions. There is, however, an interesting loophole: A nonzero vacuum expectation value of a Higgs-like vector constructed from the metric can break chiral invariance without changing the lowest-order Einstein-Yang-Mills form of the gravitational lagrangian.
Photodissociation of acetylene and bromoacetylene in the vacuum ultraviolet - Production of electronically excited C2H and C2

The photodissociation of C2H2 and BrC2H in the vacuum ultraviolet produces nearly identical quasicontinuous emissions in the region 4000 to above 5500 A. It is concluded that the continua are most likely associated with the electronically excited C2H (C2H*) in both cases. Based on this conclusion the following spectroscopic and thermochemical data are derived from the thresholds of incident wavelength to produce the continua (1305±3 A and 1540±3 A, respectively, for C2H2 and BrC2H): The electronic energy of C2H, E0(C2H) ? 4.11±0.05 eV, D0(Br–C2H) = 91±1 kcal mol−1 (381±4 kJ mol−1), and ΔHmDfo(BrC2H) = 64.2±1.5 kcal mol−1 (269±6 kJ mol−1). The photolysis of BrC2H yields the C2 Swan bands in addition to the C2H* by the spin forbidden process. The fluorescence yield has been measured as a function of incident wavelength for C2H2 and BrC2H. The fluorescence yield curves follow the absorption spectra of C2H2 and BrC2H, indicating that the C2H* is predissociated from the initially formed electronic states. The ...
Reduced Order Modeling and Vibration Analysis of Mistuned Bladed Disk Assemblies With Shrouds

This paper presents important improvements and extensions to a computationally efficient reduced order modeling technique for the vibration analysis of mistuned bladed disks. In particular, this work shows how the existing modeling technique is readily extended to turbomachinery rotors with shrouded blades. The modeling technique employs a component mode synthesis approach to systematically generate a reduced order model (ROM) using component modes calculated from a finite element model (FEM) of the rotor. Based on the total number of degrees of freedom, the ROM is typically two or three orders of magnitude smaller than the FEM. This makes it feasible to predict the forced response statistics ofmistuned bladed disks using Monte Carlo simulations. In this work, particular attention is devoted to the introduction of mistuning into the ROM of a shrouded assembly. Mistuning is modeled by projecting the mistuned natural frequencies of a single, cantilever blade with free shrouds onto the harmonic modes of the shrouded blade assembly. Thus, the necessary mistuning information may be measured by testing individual blades.
Free radical ring expansion of fused-methylenecyclobutanes

Summary Fused methylenecyclobutanes comprise a new free radical ring expansion system leading to cis-fused methylenecycloheptanes
ON THE STRENGTH OF THE FINITE INTERSECTION PRINCIPLE

We study the logical content of several maximality principles re- lated to the finite intersection principle (FIP) in set theory. Classically, these are all equivalent to the axiom of choice, but in the context of reverse math- ematics their strengths vary: some are equivalent to ACA0 over RCA0, while others are strictly weaker, and incomparable with WKL0. We show that there is a computable instance of FIP all of whose solutions have hyperimmune de- gree, and that every computable instance has a solution in every nonzero c.e. degree. In terms of other weak principles previously studied in the literature, the fomer result translates to FIP implying the omitting partial types princi- ple (OPT). We also show that, modulo � 0 induction, FIP lies strictly below the atomic model theorem (AMT).
Stroboscopic microscopy of ferroelectric liquid crystals

We have studied the switching of surface-stabilized ferroelectric-liquid-crystal (SSFLC) cells using stroboscopic microscopy. We find that the switching process in the chevron-layer-shaped SSFLC's is mediated by domains that occur at the chevron interface and that are nucleated both heterogeneously and homogeneously; that some features of the growth of the domains can be described well by existing theories; and that the peculiar terminal ``speedboat'' shape of the domains is a function of the applied electric field and the sample temperature. We examine the possible mechanisms that result in asymmetries in domain-wall velocities.
Synthesis and monoamine transporter affinity of 2β-carbomethoxy-3β-(2″-, 3″- or 4″-substituted) biphenyltropanes

Abstract A series of 11 novel 3β-substituted biphenyltropanes was synthesized and evaluated by selective radioligand binding assays for affinity to monoamine transporters. Both 5-HTT potency and selectivity for 5-HTT over DAT was greatest with electron withdrawing group at the 3″-position.
Stress-related hydrogen degradation of 0.1-/spl mu/m InP HEMTs and GaAs PHEMTs

Hydrogen degradation of III-V field-effect transistors (FETs) is a serious reliability concern. Previous work has shown that threshold-voltage shifts induced by H/sub 2/ exposure in 1-/spl mu/m-channel InP high-electron mobility transitors (HEMTs) can be attributed to compressive stress in the gate due to the formation of TiH/sub x/ in Ti/Pt/Au gates. The compressive stress affects the device characteristics through the piezoelectric effect. This paper examined the H/sub 2/ sensitivity of 0.1-/spl mu/m strained-channel InP HEMTs and GaAs pseudomorphic HEMTs. After exposure to H/sub 2/, the threshold voltage V/sub T/ of both types of devices shifted positive. This positive shift in V/sub T/ is predicted by a model for hydrogen-induced piezoelectric effect. In situ V/sub T/ measurements reveal distinct time dependences of the V/sub T/ shifts, which are also consistent with stress-related phenomena.
Characterization of a Dynamic String Method for the Construction of Transition Pathways in Molecular Reactions

We explore the theoretical foundation of different string methods used to find dominant reaction pathways in high-dimensional configuration spaces. Pathways are assessed by the amount of reactive flux they carry and by their orientation relative to the committor function. By examining the effects of transforming between different collective coordinates that span the same underlying space, we unmask artificial coordinate dependences in strings optimized to follow the free energy gradient. In contrast, strings optimized to follow the drift vector produce reaction pathways that are significantly less sensitive to reparameterizations of the collective coordinates. The differences in these paths arise because the drift vector depends on both the free energy gradient and the diffusion tensor of the coarse collective variables. Anisotropy and position dependence of diffusion tensors arise commonly in spaces of coarse variables, whose generally slow dynamics are obtained by nonlinear projections of the strongly c...
Horseshoes, hand grenades, and treatment effects? Reassessing whether nonexperimental estimators are biased

Randomized controlled trials (RCTs) are considered the gold standard in estimating treatment effects. When an RCT is infeasible, regression modeling or statistical matching are often used instead. Nonexperimental methods such as these could produce unbiased estimates if the underlying assumptions hold, but those assumptions are usually not testable. Most prior studies testing nonexperimental designs find that they fail to produce unbiased estimates, but these studies have examined weaker evaluation designs. The present study addresses these limitations using student-level data based on a large-scale RCT of charter schools for which standardized achievement tests are the key outcome measure. The use of baseline data that are strongly predictive of the key outcome measures considerably reduces but might not completely eliminate bias.
Coronal Information from EUV Disk Spectral Line Intensities

Center of disk EUV line intensities from quiet and active regions are used for determining an analytical expression for the variation of temperature with height in the lower corona, including the corona-chromosphere transition region. This approach imposes two coronal temperature regimes in both quiet and active regions. In each case the lower temperature regime is a continuation of the transition region, reaching a maximum of about 1.4 million deg in the quiet and 1.7 million deg in the active region. In the quiet region the high temperature regime, assumed isothermal, has a temperature of about 2.4 million deg, and in the active region, about 4.2 million deg.
Cross-Task Knowledge-Constrained Self Training

We present an algorithmic framework for learning multiple related tasks. Our framework exploits a form of prior knowledge that relates the output spaces of these tasks. We present PAC learning results that analyze the conditions under which such learning is possible. We present results on learning a shallow parser and named-entity recognition system that exploits our framework, showing consistent improvements over baseline methods.
A new synthesis of aryl hetaryl ketones via SRN1 reactions of halogenated heterocycles with potassiophenylacetonitrile followed by phase-transfer catalyzed decyanation

Reaction of halogenated pyridines, quinolines, pyrimidines, and pyrazines with potassiophenylacetonitrile (5) in liquid ammonia under near-uv irradiation affords secondary nitriles, which then undergo oxidative decyanation under phase-transfer catalytic conditions to afford aryl hetaryl ketones in excellent yields.
Hidden SL(n) symmetry in conformal field theories

We prove that an irreducible representation of the Virasoro algebra can be extracted from an irreducible representation space of theSL(2, ℛ) current algebra by putting a constraint on the latter using the Becchi-Rouet-Stora-Tyutin formalism. Thus there is aSL(2, ℛ) symmetry in the Virasoro algebra, but it is gauged and hidden. This construction of the Virasoro algebra is the quantum analogue of the Hamiltonian reduction. We then are naturally lead to consider a constrainedSL(2, ℛ) Wess-Zumino-Witten model. This system is also related to quantum field theory of coadjoint orbit of the Virasoro group. Based on this result, we present a canonical derivation of theSL(2, ℛ) current algebra in Polyakov's theory of two-dimensional gravity; it is a manifestation of theSL(2, ℛ) symmetry in conformal field theory hidden by the quantum Hamiltonian reduction. We also discuss the quantum Hamiltonian reduction of theSL(2, ℛ) current algebra and its relation to theW n -algebra of Zamolodchikov. This makes it possible to define a natural generalization of the geometric action for theW n -algebra despite its non-Lie-algebraic nature.
A frequency-domain estimator for use in adaptive control systems

This paper presents a frequency-domain estimator that can identify both a parametrized nominal model of a plant as well as a frequency-domain bounding function on the modeling error associated with this nominal model. This estimator, which we call a robust estimator, can be used in conjunction with a robust control-law redesign algorithm to form a robust adaptive controller.
Radical addition of varied functionality via phenylselenenyl transfer

Abstract Simple phenylselenenyl ketones, esters, nitriles, and sulfones were added to octene upon photolysis. These addition reactions illustrate that the process of carbon-carbon bond formation accompanied by phenylselenenyl transfer possesses more general applicability than has previously been demonstrated or suspected.
The data acquisition system for SLD

Abstract This paper describes the data acquisition system planned for the SLD detector, which is being constructed for use with the SLAC linear collider (SLC). Analog electronics, heavily incorporating hybrid and custom VLSI circuitry, is mounted on the detector itself. Extensive use is made of multiplexing through optical fibers to a FASTBUS readout system. The low repitition rate of the SLC allows a relatively simple software-based trigger. Hardware and software processors within the acquisition modules are used to reduce the large volume of data per event and to calibrate the electronics. A farm of microprocessors is used for full reconstruction of a sample of events prior to transmission to the host.
Eight-vertex model in lattice statistics and one-dimensional anisotropic heisenberg chain. I. Some fundamental eigenvectors

Abstract We obtain some simple eigenvectors of the transfer matrix of the zero-field eight-vertex model. These are also eigenvectors of the Hamiltonian of the one-dimensional anisotropic Heisenberg chain. We also obtain new equations for the matrix Q ( v ) introduced in earlier papers.
NJ and PA Once Again: What Happened to Employment When the PA-NJ Minimum Wage Differential Disappeared?

Card and Krueger’s analysis of the impact of the 1992 increase in the New Jersey (NJ) state minimum wage on employment in fast-food restaurants in NJ and Pennsylvania (PA) is very well known. In 1996 and 1997, the federal minimum wage was increased from $4.25 to $5.15, thereby increasing the minimum wage by $0.90 in PA but by just $0.10 in NJ. We use CPS data to examine the impacts of this increase on employment of likely minimum wage workers in the two states, using DID and DIDID estimators that exploit within-state and between-state comparisons. We find consistent evidence that employment of ‘‘at-risk’’ groups was negatively affected in PA relative to other groups in PA and to comparable groups in NJ. Eastern Economic Journal (2009) 35, 115–128. doi:10.1057/eej.2008.1
An XMM–Newton and Chandra study of the starburst galaxy IC 10

We present an X-ray study of our nearest starburst galaxy IC 10, based on XMM-Newton and Chandra observations. A list of 73 XMM-Newton and 28 Chandra detections of point-like X-ray sources in the field is provided; a substantial fraction of them are likely stellar objects in the Milky Way due to the low Galactic latitude location of IC 10. The brightest source in the IC 10 field, X-1, has a mean 0.3-8.0 keV luminosity of ∼1.2 × 10 38 erg s -1 and shows a large variation by a factor of up to ∼6 on time-scales of ∼10 4 s during the XMM-Newton observation. The X-ray spectra of the source indicate the presence of a multicolour blackbody accretion disc with an inner disc temperature T in 1.1 keV. These results are consistent with the interpretation of the source as a stellar mass black hole (BH), probably accreting from a Wolf-Rayet (W-R) star companion. We infer the mass of this BH to be ∼4 M ○. if it is not spinning, or a factor of up to ∼6 higher if there is significant spinning. We also detect an apparent diffuse soft X-ray emission component of IC 10. An effective method is devised to remove the X-ray CCD-readout streaks of X-1 that strongly affect the study of the diffuse component in the XMM-Newton and Chandra observations. We find that the diffuse X-ray morphology is oriented along the optical body of the galaxy and is chiefly associated with starburst regions. The diffuse component can be characterized by an optically thin thermal plasma with a mean temperature of ∼4 x 10 6 K and a 0.5-2 keV luminosity of ∼8 x 10 37 erg s -1 , representing only a small fraction of the expected mechanical energy inputs from massive stars in the galaxy. There is evidence that the hot gas is driving outflows from the starburst regions; therefore, the bulk of the energy inputs may be released in a galactic wind.
CHARACTERISTIC SCALES IN STELLAR CLUSTERING : A TRANSITION NEAR THE DISK SCALE HEIGHT

The autocorrelation function provides an objective test for the existence of special scales in the hierarchical clustering of young stars. We apply this measure to single-star photometry for the brightest main-sequence stars in the Small Magellanic Cloud (SMC), the Large Magellanic Cloud (LMC), M33, and M31, using data from the Magellanic Clouds Photometric Survey and the Massey Local Group Survey. Our primary result is the identification of a transition to a higher correlation dimension (weaker clustering) at 1 kpc in the LMC and M31, and at 300 pc in M33. We suggest that this transition marks the large-scale regime where disk geometry and dynamics set the scale for structure. On smaller scales, the correlation functions for each galaxy are scale-free over at least 2 orders of magnitude, with a projected correlation dimension varying from 1.0 for M31 to 1.8 for the SMC. This variation is probably caused by a combination of differences in stellar ages and masses, physical environment, and extinction.
Single-frequency output from a broadband-tunable external-fiber-cavity laser

A broadly tunable single-frequency external-cavity laser is demonstrated by coupling a tunable fiber-optic evanescent-grating reflective filter1,2 to an AR-coated semiconductor laser. Tunable external-fiber-cavity lasers have recently been demonstrated,3,4 but single-frequency operation was not observed due either to weak feedback3 or excessively large cavity lengths.4 For the laser presented in this paper, enhanced tuning range and single-frequency operation are achieved by using a high reflectivity filter (>80%) and a relatively small cavity length (≃8 cm).
The chemistry of the mechanical bond

The use of templation in the synthesis of unnatural products where two or more components are mechanically interlocked has not only raised the efficiency of their production to near quantitative levels in some instances, but the molecular recognition that aids and abets the templation is also part and parcel of the molecules after they have been prepared, purified and presented for investigation. The fact that the molecular recognition ‘lives on’ in mechanically interlocked molecules, following their templated formation, makes them prime candidates for applications that straddle the scientific and technical worlds from devices that could spawn new information technologies to integrated systems that could have fundamental applications in the health-care industries. The challenge to make more and more sophisticated compounds is predicated upon our fundamental understanding of the nature of the mechanical bond and how this associated knowledge base can be employed to do complex systems chemistry in very different environments where emergent phenomena become the order of the day (critical review, 104 references).
Quantum phase transitions in holographic models of magnetism and superconductors

We study a holographic model realizing an ``antiferromagnetic'' phase in which a global $SU(2)$ symmetry representing spin is broken down to a $U(1)$ by the presence of a finite electric charge density. This involves the condensation of a neutral scalar field in a charged anti--de Sitter black hole. We observe that the phase transition for both neutral and charged (as in the standard holographic superconductor) order parameters can be driven to zero temperature by a tuning of the UV conformal dimension of the order parameter, resulting in a quantum phase transition of the Berezinskii-Kosterlitz-Thouless--type. We also characterize the antiferromagnetic phase and an externally forced ferromagnetic phase by showing that they contain the expected spin waves with linear and quadratic dispersions, respectively.
The effect of the Caloris impact on the mantle dynamics and volcanism of Mercury

[1] The MESSENGER spacecraft has imaged more than 95% of the surface of Mercury. Images of the Caloris impact basins, along with several smaller impact structures, reveal evidence for volcanic plains within and exterior to the basin that are younger than the basin rim and might be associated with the long-term aftermath of Caloris's formation. The broad influence of Caloris on the surface of Mercury indicates that it might also affect heat flow within the mantle and thereby the core dynamics. Here we investigate possible links between the Caloris impact on Mercury, thermochemical evolution of the mantle, and the volcanism within and surrounding the basins. A finite element model of thermochemical convection in a spherical shell is used to explore the consequences of the formation of large impacts in the Mercurian mantle. While the impact cannot have formed the younger melts directly, the thermal impulse from such a large impact can alter the underlying mantle dynamics, producing subsequent volcanism far from the impact site. We further find that despite the relatively thin Mercurian mantle, the expected heating from the Caloris impact cannot penetrate to the core and should thus have minimal effects on a dynamo. This is largely due to the high expected velocity of impactors at Mercury and thus relatively small size of the Caloris-forming impactor.
Shared knowledge and the coagglomeration of occupations

Gabe T. M. and Abel J. R. Shared knowledge and the coagglomeration of occupations, Regional Studies. This paper examines the extent to which people in different occupations locate near one another, or coagglomerate. Ellison–Glaeser coagglomeration indices are constructed for US occupations and used to investigate factors influencing the geographic concentration of economic activity. Empirical results reveal that occupations with similar knowledge requirements tend to coagglomerate, and the importance of shared knowledge is larger in metropolitan areas than in states. An extension to the main analysis finds that, when focusing on metropolitan areas, the largest effects on coagglomeration are due to shared knowledge about engineering and technology, arts and humanities, manufacturing and production, and mathematics and science.
Embedding Free Burnside Groups in Finitely Presented Groups

We construct an embedding of a free Burnside group B(m,n) of odd exponent n > 248 and rank m >1 in a finitely presented group with some special properties. The main application of this embedding is an easy construction of finitely presented nonamenable groups without noncyclic free subgroups (which provides a new finitely presented counterexample to the von Neumann problem on amenable groups). As another application, we construct weakly finitely presented groups of odd exponent n ≫ 1 which are not locally finite.
An optimization-based approach for QoS routing in high-bandwidth networks

In this paper, we propose an optimization-based approach for Quality of Service (QoS) routing in high-bandwidth networks. We view a network that employs QoS routing as an entity that distributively optimizes some global utility function. By solving the optimization problem, the network is driven to an efficient operating point. In earlier work, it has been shown that when the capacity of the network is large, this optimization takes on a simple form, and once the solution to this optimization problem is found, simple proportional QoS routing schemes will suffice. However, this optimization problem requires global information. We develop a distributed and adaptive algorithm that can efficiently solve the optimization online. Compared with existing QoS routing schemes, the proposed optimization-based approach has the following advantages: 1) the computation and communication overhead can be greatly reduced without sacrificing performance; 2) the operating characteristics of the network can be analytically studied; and 3) the desired operating point can be tuned by choosing appropriate utility functions.
Current Resources for Evidence-Based Practice, March/April 2012

A Review of Reviews: Systematic, Integrative, Meta-Analyses, and Metasynthesis Evidence-based practice relies on the availability of the highest level of clinical evidence. The sheer volume of published studies available to the contemporary clinician can be overwhelming. Although a number of resources, such as this column, are available to organize and summarize clinical evidence, clinicians are often uncertain about the differences in types of reviews when conducting a search for clinical information. For instance, what is the difference between an integrative review and a systematic review or between a metasynthesis and a meta-analyses? Can qualitative research be included in a systematic review? How do these types of methods inform evidencebased practice?
GRASSLAND MANAGEMENT AND CONVERSION INTO GRASSLAND: EFFECTS ON SOIL CARBON

Grasslands are heavily relied upon for food and forage production. A key component for sustaining production in grassland ecosystems is the maintenance of soil organic matter (SOM), which can be strongly influenced by management. Many management techniques intended to increase forage production may potentially increase SOM, thus sequestering atmospheric carbon (C). Further, conversion from either cultivation or native vegetation into grassland could also sequester atmospheric carbon. We reviewed studies examining the influence of improved grassland management practices and conversion into grasslands on soil C worldwide to assess the potential for C sequestration. Results from 115 studies containing over 300 data points were analyzed. Management improvements included fertilization (39%), improved grazing management (24%), conversion from cul- tivation (15%) and native vegetation (15%), sowing of legumes (4%) and grasses (2%), earthworm introduction (1%), and irrigation (1%). Soil C content and concentration in- creased with improved management in 74% of the studies, and mean soil C increased with all types of improvement. Carbon sequestration rates were highest during the first 40 yr after treatments began and tended to be greatest in the top 10 cm of soil. Impacts were greater in woodland and grassland biomes than in forest, desert, rain forest, or shrubland biomes. Conversion from cultivation, the introduction of earthworms, and irrigation resulted in the largest increases. Rates of C sequestration by type of improvement ranged from 0.1 1 to 3.04 Mg C-ha-l yr-l, with a mean of 0.54 Mg C-ha-l yr-l, and were highly influenced by biome type and climate. We conclude that grasslands can act as a significant carbon sink with the implementation of improved management.
Optimal Worst-Case Coverage of Directional Field-of-View Sensor Networks

Sensor coverage is a fundamental sensor networking design and use issue that in general tries to answer the questions about the quality of sensing (surveillance) that a particular sensor network provides. Although isotropic sensor models and coverage formulations have been studied and analyzed in great depth recently, the obtained results do not easily extend to, and address the coverage of directional and field-of-view sensors such as imagers and video cameras. In this paper, we present an optimal polynomial time algorithm for computing the worst-case breach coverage in sensor networks that are comprised of directional "field-of-view" (FOV) sensors. Given a region covered by video cameras, a direct application of the presented algorithm is to compute "breach", which is defined as the maximal distance that any hostile target can maintain from the sensors while traversing through the region. Breach translates to "worst-case coverage" by assuming that in general, targets are more likely to be detected and observed when they are closer to the sensors (while in the field of view). The approach is amenable to the inclusion of any sensor detection model that is either independent of, or inversely proportional to distance from the targets. Although for the sake of discussion we mainly focus on square fields and model the sensor FOV as an isosceles triangle, we also discuss how the algorithm can trivially be extended to deal with arbitrary polygonal field boundaries and sensor FOVs, even in the presence of rigid obstacles. We also present several simulation-based studies of the scaling issues in such coverage problems and analyze the statistical properties of breach and its sensitivity to node density, locations, and orientations. A simple grid-based approximation approach is also analyzed for comparison and validation of the implementation
A Dynamic Model of Social Network Formation

We consider a dynamic social network model in which agents play repeated games in pairings determined by a stochastically evolving social network. Individual agents begin to interact at random, with the interactions modeled as games. The game payoffs determine which interactions are reinforced, and the network structure emerges as a consequence of the dynamics of the agents' learning behavior. We study this in a variety of game-theoretic conditions and show that the behavior is complex and sometimes dissimilar to behavior in the absence of structural dynamics. We argue that modeling network structure as dynamic increases realism without rendering the problem of analysis intractable.
Contra-directional two-wave mixing in photorefractive media

Abstract The energy transfer between two counter-propagating beams in photorefractive media is analyzed. A solution of a non-linear model of holographic two-wave mixing is presented. Expressions for the transmissivity are obtained and discussed.
Structure of the Solar Oscillation with Period Near 160 Minutes

The solar oscillation with period near 160 minutes is found to be unique in a spectrum computed over the range of periods from about 71 to 278 minutes. A best estimate of the period is 160.0095 + or - 0.001 minutes, which is different from 160 minutes (one ninth of a day) by a highly significant amount. The width of the peak is approximately equal to the limiting resolution that can be obtained from an observation lasting 6 years, which suggests that the damping time of the oscillations is considerably longer than 6 years. A suggestion that this peak might be the result of a beating phenomenon between the five minute data averages and a solar oscillation with period near five minutes is shown to be incorrect by recomputing a portion of the spectrum using 15 second data averages.
Max 2-SAT with up to 108 qubits

We experimentally study the performance of a programmable quantum annealing processor, the D-Wave One (DW1) with up to 108 qubits, on maximum SAT problem with 2 variables per clause (MAX 2-SAT) problems. We consider ensembles of random problems characterized by a fixed clause density, an external parameter which we tune through its critical value in our experiments. We demonstrate that the DW1 is sensitive to the critical value of the clause density. The DW1 results are verified and compared with akmaxsat, an exact, state-of-the-art algorithm. We study the relative performance of the two solvers and how they correlate in terms of problem hardness. We find that the DW1 performance scales more favorably with problem size and that problem hardness correlation is essentially non-existent. We discuss the relevance and limitations of such a comparison.
Observations of Mass Loss from the Transiting Exoplanet HD 209458b

Using the new Cosmic Origins Spectrograph on the Hubble Space Telescope, we obtained moderate-resolution, high signal/noise ultraviolet spectra of HD 209458 and its exoplanet HD 209458b during transit, both orbital quadratures, and secondary eclipse. We compare transit spectra with spectra obtained at non-transit phases to identify spectral features due to the exoplanet's expanding atmosphere. We find that the mean flux decreased by 7.8% ± 1.3% for the C II 1334.5323 A and 1335.6854 A lines and by 8.2% ± 1.4% for the Si III 1206.500 A line during transit compared to non-transit times in the velocity interval –50 to +50 km s–1. Comparison of the C II and Si III line depths and transit/non-transit line ratios shows deeper absorption features near –10 and +15 km s–1 and less certain features near –40 and +30-70 km s–1, but future observations are needed to verify this first detection of velocity structure in the expanding atmosphere of an exoplanet. Our results for the C II lines and the non-detection of Si IV 1394.76 A absorption are in agreement with Vidal-Madjar et al., but we find absorption during transit in the Si III line contrary to the earlier result. The 8% ± 1% obscuration of the star during transit is far larger than the 1.5% obscuration by the exoplanet's disk. Absorption during transit at velocities between –50 and +50 km s–1 in the C II and Si III lines requires high-velocity ion absorbers. Assuming hydrodynamic model values for the gas temperature and outflow velocity at the limb of the outflow as seen in the C II lines, we find mass-loss rates in the range (8-40)×1010 g s–1. These rates assume that the carbon abundance is solar, which is not the case for the giant planets in the solar system. Our mass-loss rate estimate is consistent with theoretical hydrodynamic models that include metals in the outflowing gas.
Nonparametric inference procedure for percentiles of the random effects distribution in meta-analysis

To investigate whether treating cancer patients with erythropoiesis-stimulating agents (ESAs) would increase the mortality risk, Bennett et al. [Journal of the American Medical Association 299 (2008) 914–924] conducted a meta-analysis with the data from 52 phase III trials comparing ESAs with placebo or standard of care. With a standard parametric random effects modeling approach, the study concluded that ESA administration was significantly associated with increased average mortality risk. In this article we present a simple nonparametric inference procedure for the distribution of the random effects. We re-analyzed the ESA mortality data with the new method. Our results about the center of the random effects distribution were markedly different from those reported by Bennett et al. Moreover, our procedure, which estimates the distribution of the random effects, as opposed to just a simple population average, suggests that the ESA may be beneficial to mortality for approximately a quarter of the study populations. This new meta-analysis technique can be implemented with study-level summary statistics. In contrast to existing methods for parametric random effects models, the validity of our proposal does not require the number of studies involved to be large. From the results of an extensive numerical study, we find that the new procedure performs well even with moderate individual study sample sizes.
An overview of thermophotovoltaic generation of electricity

This paper provides an overview of the developments in thermophotovoltaic (TPV) generation of electricity that have occurred during relatively recent years (from approximately 1994 to October 1998). The components considered are the semiconductor converter, the radiator, and the means of recirculation of unusable, long-wavelength photons. A short account of the functions of each of these, their mode of operation and their performance is also given. Complete systems are also considered briefly and we conclude by offering some speculation of the future of this technology.
An ODMG-compatible testbed architecture for scalable management and analysis of physics data

This paper describes a testbed architecture for the investigation and development of scalable approaches to the management and analysis of massive amounts of high energy physics data. The architecture has two components: an interface layer that is compliant with a substantial subset of the ODMG-93 Version 1.2 specification, and a lightweight object persistence manager that provides flexible storage and retrieval services on a variety of single- and multi-level storage architectures, and on a range of parallel and distributed computing platforms.
Developmental Biology of Fern Gametophytes

Preface Abbreviations 1. Introduction Part I. The Beginning: 2. The spore - beginning of the gametophytic phase 3. Physiology of spore germination 4. Cell determination and morphogenesis during germination 5. Biochemical cytology and biochemistry of germination Part II. Growth and Maturation: 6. Developmental physiology of gametophytes - the germ filament 7. Developmental physiology of gametophytes - induction of planar growth 8. Role of protein and nucleic acid synthesis in planar growth 9. Vegetative and reconstitutive growth of gametophytes Part III. Reproductive Strategies: 10. Control of differentiation of sex organs on gametophytes 11. Sexuality and genetics of gametophytes 12. Gametogenesis and fertilization 13. Apogamy - an alternate development program of gametophytes 14. Apospory - formation of gametophytes without meiosis References Author index Subject index.