cssi/SciSciGPT-SciSciNet huggingface dataset:
Synthesis and primary characterization of self-assembled peptide-based hydrogels.

Hydrogels based on peptide self-assembly form an important class of biomaterials that find application in tissue engineering and drug delivery. It is essential to prepare peptides with high purity to achieve batch-to-batch consistency affording hydrogels with reproducible properties. Automated solid-phase peptide synthesis coupled with optimized Fmoc (9-fluorenylmethoxycarbonyl) chemistry to obtain peptides in high yield and purity is discussed. Details of isolating a desired peptide from crude synthetic mixtures and assessment of the peptide’s final purity by high-performance liquid chromatography and mass spectrometry are provided. Beyond the practical importance of synthesis and primary characterization, techniques used to investigate the properties of hydrogels are briefly discussed.
On sufficiency of dominant strategy implementation in environments with correlated types

We show that for any mechanism there exists an equivalent dominant strategy incentive compatible mechanism for social choice environments with correlated types when agent’s matrix of conditional probabilities satisfies the full rank condition.
Catalytic asymmetric synthesis of all-carbon quaternary stereocenters

Only a few catalytic asymmetric C—C bond-forming reactions have been shown to be useful for constructing all-carbon quaternary stereocenters. This Perspective examines the current state of such methods.
Split quaternionic analysis and separation of the series for SL(2,R) and SL(2,C)/SL(2,R)

Abstract We extend our previous study of quaternionic analysis based on representation theory to the case of split quaternions H R . The special role of the unit sphere in the classical quaternions H – identified with the group SU ( 2 ) – is now played by the group SL ( 2 , R ) realized by the unit quaternions in H R . As in the previous work, we use an analogue of the Cayley transform to relate the analysis on SL ( 2 , R ) to the analysis on the imaginary Lobachevski space SL ( 2 , C ) / SL ( 2 , R ) identified with the one-sheeted hyperboloid in the Minkowski space M . We study the counterparts of Cauchy–Fueter and Poisson formulas on H R and M and show that they solve the problem of separation of the discrete and continuous series. The continuous series component on H R gives rise to the minimal representation of the conformal group SL ( 4 , R ) , while the discrete series on M provides its K-types realized in a natural polynomial basis. We also obtain a surprising formula for the Plancherel measure of SL ( 2 , R ) in terms of the Poisson-type integral on the split quaternions H R . Finally, we show that the massless singular functions of four-dimensional quantum field theory are nothing but the kernels of projectors onto the discrete and continuous series on the imaginary Lobachevski space SL ( 2 , C ) / SL ( 2 , R ) . Our results once again reveal the central role of the Minkowski space in quaternionic and split quaternionic analysis as well as a deep connection between split quaternionic analysis and the four-dimensional quantum field theory.
Optical and Radio Polarimetry of the M87 Jet at 0.2" Resolution

We discuss optical (HST/WFPC2 F555W) and radio (15 GHz VLA) polarimetry observations of the M87 jet taken during 1994-1995. The angular resolution of both of these observations is ∼ 0.2 ′′ , which at the distance of M87 corresponds to 15 pc. Many knot regions are very highly polarized (∼ 40 −50%, approaching the theoretical maximum for optically thin synchrotron radiation), suggesting highly ordered magnetic fields. High degrees of polarization are also observed in interknot regions. The optical and radio polarization maps share many similarities, and in both, the magnetic field is largely parallel to the jet, except in the “shock-like” knot regions (parts of HST-1, A, and C), where it becomes perpendicular to the jet. We do observe significant differences between the radio and optical polarized structures, particularly for bright knots in the inner jet, giving us important insight into the radial structure of the jet. Unlike in the radio, the optical magnetic field position angle becomes perpendicular to the jet at the upstream ends of knots HST-1, D, E and F. Moreover, the optical polarization appears to decrease markedly at the position of the flux maxima in these knots. In contrast, the magnetic field position angle observed in the radio remains parallel to the jet in most of these regions, and the decreases in radio polarization are smaller. More minor differences are seen in other jet regions. Many of the differences between optical and radio polarimetry results can be explained in terms of a model whereby shocks occur in the jet interior, where higher-energy electrons are concentrated and dominate both polarized and unpolarized emissions in the optical, while the radio maps show strong contributions from lower-energy electrons in regions with B parallel, near the jet surface.
Darboux transformations and linear parabolic partial differential equations

A method is provided to solve boundary value problems to parabolic partial differential equations of the form: u/sub t/ = u/sub x/x + f(x)u, provided f(x) is obtained as twice the second derivative of the logarithm of the wronskian of separable solutions to the heat equation and the boundary conditions result in a regular Sturm Liouville problem upon doing separation of variables. Darboux transformations are used to obtain a complete set of eigenfunctions for the boundary value problem allowing for a solution in terms of an eigenfunction expansion.
Bubbles and Self-Enforcing Debt

We characterize equilibria with endogenous debt constraints for a general equilibrium economy with limited commitment in which the only consequence of default is losing the ability to borrow in future periods. First, we show that equilibrium debt limits must satisfy a simple condition that allows agents to exactly roll over existing debt period by period. Second, we provide an equivalence result, whereby the resulting set of equilibrium allocations with self-enforcing private debt is equivalent to the allocations that are sustained with unbacked public debt or rational bubbles. In contrast to the classic result by Bulow and Rogoff (1989a), positive levels of debt are sustainable in our environment because the interest rate is sufficiently low to provide repayment incentives.
Computational catalyst screening: Scaling, bond-order and catalysis

Abstract The design of new and better heterogeneous catalysts needed to accommodate the growing demand for energy from renewable sources is an important challenge for coming generations. Most surface catalyzed processes involve a large number of complex reaction networks and the energetics ultimately defines the turn-over-frequency and the selectivity of the process. In order not to get lost in the large quantities of data, simplification schemes that still contain the key elements of the reaction are required. Adsorption and transition state scaling relations constitutes such a scheme that not only maps the reaction relevant information in terms of few parameters but also provides an efficient way of screening for new materials in a continuous multi-dimensional energy space. As with all relations they impose certain restrictions on what can be achieved and in this paper, I show why these limitations exist and how we can change the behavior through an energy-resolved approach that still maintains the screening capabilities needed in computational catalysis.
Class hierarchies in information systems: sets, types, or prototypes?

One of the cornerstones of the conceptual modeling languages devised for the specification and implementation of Information Systems, is the idea of objects grouped into classes. I begin by reviewing the various roles played by this concept in the development and maintenance of Information Systems: specification of type information, repository of constraints to be verified, and maintenance of an associated set of objects (the “extent”).
Reallocation, Competition, and Productivity: Evidence from a Financial Liberalization Episode

This article studies the impact of distortions in the access to international capital markets on competition and productivity. I show that a reduction in these distortions leads to an increase in aggregate productivity through two different channels. First, firms that were previously credit constrained respond to better financing terms by increasing their investment in technology, a reallocation effect. Secondly, non-constrained firms also expand their investment in technology because of increased competition, a pro-competitive effect. I provide evidence for these two channels using firm-level census data from the deregulation of international financial flows in Hungary.
Koide’s Formula Follows from Nonlinear Dynamics of Quantum Fields

In this brief report we argue that Koide’s formula arises from universal attributes of nonlinear dynamics in field theory. Feigenbaum scaling not only provides a natural paradigm for generating particle masses and coupling charges, but also a basis for understanding the family structure of fermions.
The Wham Northern Sky Survey and the Nature of the Warm Ionized Medium in the Galaxy

The Wisconsin H-Alpha Mapper (WHAM) has completed a velocity-resolved map of diffuse Hα emission of the entire northern sky, providing the first comprehensive picture of both the distribution and kinematics of diffuse ionized gas in the Galaxy. WHAM continues to advance our understanding of the physical conditions of the warm ionized medium through observations of other optical emission lines throughout the Galactic disk and halo. We discuss some highlights from the survey, including an optical window into the inner Galaxy and the relationship between H I and H II in the diffuse ISM.
Role of the "little brain" in the gut in water and electrolyte homeostasis.

The enteric nervous system plays a key role in maintenance of body fluid homeostasis by regulating the transport of ions by the intestinal epithelium. The epithelial cells normally absorb large volumes of fluid and ions daily, but tonically active submucosal neurons continuously suppress ion transport and limit the absorptive capacity of the intestine. Specialized nerve endings detect chemical, osmotic, or thermal alterations of the luminal contents or mechanical activity of the gut wall and encode this information as action potentials that propagate along nerve processes to the ganglia. Information transfer within the ganglia occurs at nicotinic cholinergic or other synapses. Ion transport is altered when neurotransmitters released from motor neurons interact with receptors on epithelial cells to initiate stimulus-response coupling. The signals that transduce changes in epithelial ion transport are largely unknown, except for acetylcholine, but may include vasoactive intestinal peptide or other peptides....
Triple Aryne-Tetrazine Reaction Enabling Rapid Access to a New Class of Polyaromatic Heterocycles.

One of the most challenging goals of modern synthetic chemistry is to develop multi-step reactions for rapid and efficient access to complex molecules. We report a triple aryne–tetrazine reaction that enables rapid access to a new class of polyaromatic heterocycles. This new reaction, which couples diverse reactivity modes between simple aryne and tetrazine starting materials, proceeds in a single operation and takes less than 5 minutes in air with no metal catalyst.
Inward shift of outer radiation belt electrons as a function of Dst index and the influence of the solar wind on electron injections into the slot region

[1] The radial positioning of radiation belt electrons as a function of the Dst index and the controlling solar wind parameters for deep penetration of energetic electrons into the inner magnetosphere are investigated. Using 2–6 MeV electron data from the Solar, Anomalous, and Magnetospheric Particle Explorer (SAMPEX) from January 1995 to June 2004, we examine the L location of energetic electron deepest penetration, L location of the maximum flux, and L location of the maximum flux enhancement and variation over the duration of 119 moderate and strong isolated geomagnetic storms. We find that the L location of deepest penetration, L location of the maximum flux at the end of electron injections, and L location of the maximum flux variation have strong correlations with the minimum Dst index. Although the variation and radial positioning of radiation belt electrons is clearly associated with the Dst index, their deep penetration into the slot region (2 < L < 3) is not directly correlated with the Dst index in an obvious way. It is also known that the Dst index can be accurately predicted based on solar wind parameters. Thus, the necessary and sufficient combination of solar wind conditions for the occurrence of injection events into the slot region, between L = 2–3, are also investigated. We find a total of 23 injection events at L = 2.5 from 1995 to 2004 and that when certain solar wind conditions are met, an injection event at L = 2.5 is ensured. We also find that the electron flux preconditioning is an important factor influencing electron injections at L = 2.5.
Democratization and Clientelism : Why are Young Democracies Badly Governed?

This paper identifies systematic performance differences between younger and older democracies: younger democracies are more corrupt; exhibit less rule of law, lower levels of bureaucratic quality, and lower secondary school enrollments; and spend more on public investment and government workers. Only one theory explains the effects of democratic age on the wide range of policy outcomes examined here-the inability of political competitors in younger democracies to make credible promises to citizens. This explanation, first advanced in Keefer and Vlaicu (2004), offers a concrete interpretation of what political institutionalization might mean, and why it is that young democracies frequently fail to become older and well-performing democracies. A variety of tests support this explanation against alternatives. The effect of democratic age remains large even after controlling for the possibilities that voters are less well-informed in young democracies, that young democracies have systematically different political and electoral institutions, or that young democracies exhibit more polarized societies.
High-precision study of Cs polarizabilities

We present results of the first-principles calculation of Cs dipole static polarizabilities for the Ns (N=6-12), $Np_j$ (N=6-10), and $Nd_j$ (N=5-10) states using the relativistic all-order method. In our implementation of the all-order method, single and double excitations of Dirac-Fock wave functions are included to all orders in perturbation theory. Additional calculations are carried out for the dominant terms and the uncertainties of our final values are estimated for all states. A comprehensive review of the existing theoretical and experimental studies of the Cs polarizabilities is also carried out. Our results are compared with other values where they are available. These calculations provide a theoretical benchmark for a large number of Cs polarizabilities.
Determinant Bundles for Abelian Schemes

To a symmetric, relatively ample line bundle on an Abelian scheme one can associate a linear combination of the determinant bundle and the relative canonical bundle, which is a torsion element in the Picard group of the base. We improve the bound on the order of this element found by Faltings and Chai. In particular, we obtain an optimal bound when the degree of the line bundle d is odd and the set of residue characteristics of the base does not intersect the set of primes p dividing d, such that p≡-1 mod(4) and \(p \leqslant 2g - 1\), where g is the relative dimension of the Abelian scheme. Also, we show that in some cases these torsion elements generate the entire torsion subgroup in the Picard group of the corresponding moduli stack.
Volatiles in Basaltic Glasses from the Easter‐Salas y Gomez Seamount Chain and Easter Microplate: Implications for Geochemical Cycling of Volatile Elements

[1] We present H2O, CO2, and Cl concentrations in 66 basaltic glasses from the Easter Microplate (EMP) and Easter-Salas y Gomez Seamount Chain (ESC) system in the southeastern Pacific. The EMP-ESC system is characterized by binary mixing between a depleted mid-ocean ridge basalt (MORB) mantle source (DMM) and an incompatible element and radiogenic isotope enriched source, the Salas y Gomez mantle plume (SyG). Plume material is channeled toward the ridge crest centered at ∼27°S on the east rift of the microplate. Water concentrations on the EMP are highest on the east rift at ∼27°S and become progressively lower to the north and south, following the spatial pattern of other geochemical tracers. EMP basalts have not lost H2O to degassing but have assimilated variable quantities of a Cl-rich hydrothermal component. In contrast, some seamount basalts have lost water by shallow degassing, but very few have gained Cl, indicating little assimilation of Cl-rich materials. Several ESC seamount glasses may have assimilated a hydrous component, for example, serpentinized harzburgite, during magma ascent through the lithosphere. On the basis of samples unaffected by shallow processes, the main plume component has H2O/Ce of ∼210 ± 20 and is neither preferentially enriched nor depleted in H2O relative to other similarly incompatible elements. The depleted MORB source has H2O/Ce of ∼150 ± 10. Estimated mantle volatile concentrations are 750 ± 210 ppm H2O and 40 ± 11 ppm Cl for the SyG source, 120 ± 27 ppm H2O and 4.5 ± 1.4 ppm Cl for an average EPR source, and 54 ± 12 ppm H2O and 1.7 ± 0.4 ppm Cl for the DMM source. The coupled behavior of H2O and Cl with similarly incompatible elements, coupled with elevated 3He/4He ratios, suggests that the volatiles are dominantly juvenile, representative of a component common to mantle plumes, with minor contribution from recycled lithospheric components.
Mechanical neuroscience: Emil du Bois-Reymond's innovations in theory and practice

Contemporary neuroscience unites three scientific traditions: one in anatomy that goes back to the Greeks (functional localization), one in chemistry that arose in the twentieth-century (neurotransmitters), and one in physics that arose in the nineteenth-century (electrical signals) (Clarke and Jacyna, 1987; Finger, 1994; Valenstein, 2005; McComas, 2011). Emil du Bois-Reymond is the father of the last. He's not quite Victor Frankenstein, but he's close. When du Bois-Reymond began his investigations neurophysiologists were divided. Some followed the physician Luigi Galvani (1737–1798) in ascribing the action of nerves and muscles to vital powers of “animal electricity.” Others sided with the physicist Alessandro Volta (1745–1827) in believing that the muscular contractions that Galvani observed were an artifact of electricity generated by the contact of metal with organic tissue (Pera, 1992; Piccolino, 1998; Piccolino and Bresadola, 2013). Recognizing value in both positions, du Bois-Reymond solved the problem of contact electricity, set forth a program of biological reduction, and demonstrated the electrical nature of nerve signals. In a little less than two years—from March, 1841 to January, 1843—he created the discipline of electrophysiology. That's the short version of du Bois-Reymond's innovation. We know that it's true because winners write history—at least, that's what we've been told. In the case of du Bois-Reymond, however, the truth is closer to this: those who write history win. Does this fact change his story? Consider the evidence.
Allylation and [3+2]-cycloaddition reactions of imines with allyl(cyclopentadienyl)iron(II) dicarbonyl complexes

Abstract Allyl(cyclopentadienyl)iron(II) dicarbonyl ( 1 ) reacts with N-tosylimines to give either iron-olefin complexes 2 or pyrrolidines 3 , depending on the quantity and nature of the Lewis acid and the work-up procedure.
Applications of a conservative zonal scheme to transient and geometrically complex problems

A conservative zoning technique, wherein the flow field for a finite-difference calculation is divided into several regions to simplify grid generation, is discussed and is applied in the solution of a two-dimensional problem of complex topology. Calculations are performed on two zonal, or patched, grid systems for the supersonic flow over a double-airfoil configuration. The solution is smooth and continuous across the zonal interfaces, and shock waves pass through the boundaries without distortion. In addition, the time accuracy of the zonal boundary method is verified by a two-zone cylinder calculation with a stationary inner and a rotating outer mesh. The feasibility of the zonal approach for use in the solution of geometrically complex and unsteady problems is thus demonstrated.
Voltammetric studies and determination of xenon compounds in aqueous solutions

Xenon compounds in aqueous solution at the glassy carbon electrode are irreversibly reduced to xenon(0). The observed reduction potentials vs sce for xenon compounds are: 1. Perxenate −0.49 to −0.67 V with increasing pH from 10–14; 2. Xenon trioxide −0.54 to −0.48 V with increasing pH from 7–13, and 3. Xenon difluoride at +0.19 V at pH 1.6. Platinum and mercury electrodes, are readily oxidized and are not suitable.
Some schemes related to the commuting variety

The_commuting variety_ is the pairs of NxN matrices (X,Y) such that XY = YX. We introduce the_diagonal commutator scheme_, {(X,Y) : XY-YX is diagonal}, which we prove to be a reduced complete intersection, one component of which is the commuting variety. (We conjecture there to be only one other component.) The diagonal commutator scheme has a flat degeneration to the scheme {(X,Y) : XY lower triangular, YX upper triangular}, which is again a reduced complete intersection, this time with n! components (one for each permutation). The degrees of these components give interesting invariants of permutations.
Experience-Based Human Capital and Social Capital of Outside Directors

In this article, the authors develop and test a theoretical model of the effects of outside directors' human and social capital on firm growth. They posit that outside directors' board memberships and managerial experiences have additive and interactive effects. Using a longitudinal sample of high technology firms, they test their theory and find that outside directors' membership on multiple boards, industry-specific managerial experience, and firm-specific founding experience have strong additive effects on firm growth. They also find negative interaction effects, indicating the costs of acquiring and combining certain types of outside director human and social capital within the board.
Run-Time Extensibility and Librarization of Simulation Software

Build-time configuration and environment assumptions are hampering progress and usability in scientific software. This situation, which would be utterly unacceptable in nonscientific software, somehow passes for the norm in scientific packages. The scientific software community needs reusable, easy-to-use software packages that are flexible enough to accommodate next-generation simulation and analysis demands.
Global analysis of induced transcription factors and cofactors identifies Tfdp2 as an essential coregulator during terminal erythropoiesis

Key transcriptional regulators of terminal erythropoiesis, such as GATA-binding factor 1 (GATA1) and T-cell acute lymphocytic leukemia protein 1 (TAL1), have been well characterized, but transcription factors and cofactors and their expression modulations have not yet been explored on a global scale. Here, we use global gene expression analysis to identify 28 transcription factors and 19 transcriptional cofactors induced during terminal erythroid differentiation whose promoters are enriched for binding by GATA1 and TAL1. Utilizing protein–protein interaction databases to identify cofactors for each transcription factor, we pinpoint several co-induced pairs, of which E2f2 and its cofactor transcription factor Dp-2 (Tfdp2) were the most highly induced. TFDP2 is a critical cofactor required for proper cell cycle control and gene expression. GATA1 and TAL1 are bound to the regulatory regions of Tfdp2 and upregulate its expression and knockdown of Tfdp2 results in significantly reduced rates of proliferation as well as reduced upregulation of many erythroid-important genes. Loss of Tfdp2 also globally inhibits the normal downregulation of many E2F2 target genes, including those that regulate the cell cycle, causing cells to accumulate in S phase and resulting in increased erythrocyte size. Our findings highlight the importance of TFDP2 in coupling the erythroid cell cycle with terminal differentiation and validate this study as a resource for future work on elucidating the role of diverse transcription factors and coregulators in erythropoiesis.
Magnetic braking in weakly ionized media

The combined magnetic braking-ambipolar diffusion problem in weakly ionized, rigidly rotating disks is studied. An analytical solution is presented for a disk whose angular velocity and magnetic yield vectors are aligned with the symmetry axis, illustrating the effects of the relative azimuthal drift of neutrals and ions. The effects of radial drift are added, commenting on the ratio of the characteristic ambipolar diffusion and magnetic braking time scales in high-mass and low-mass disks. A numerical calculation is used to show the combined action of these two processes.
Signals, Evolution and the Explanatory Power of Transient Information*

Pre‐play signals that cost nothing are sometimes thought to be of no significance in interactions which are not games of pure common interest. We investigate the effect of pre‐play signals in an evolutionary setting for Assurance, or Stag Hunt, games and for a Bargaining game. The evolutionary game with signals is found to have dramatically different dynamics from the same game without signals. Signals change stability properties of equilibria in the base game, create new polymorphic equilibria, and change the basins of attraction of equilibria in the base game. Signals carry information at equilibrium in the case of the new polymorphic equilibria, but transient information is the basis for large changes in the magnitude of basins of attraction of equilibria in the base game. These phenomena exemplify new and important differences between evolutionary game theory and game theory based on rational choice.
Atom Scattering from Disordered Surfaces in the Sudden Approximation: Double Collisions Effects and Quantum Liquids

The sudden approximation (SA) for scattering of atoms from surfaces is generalized to allow for double collision events and scattering from time-dependent quantum liquid surfaces. The resulting new schemes retain the simplicity of the original SA, while requiring little extra computational effort. The results suggest that inert atom (and in particular He) scattering can be used profitably to study hitherto unexplored forms of complex surface disorder.
Epidemiology of satellite anomalies and failures: A subsystem-centric approach

Epidemiology is the basic science of public health and it investigates the distribution, frequency, rates, and drivers of health-related states and illnesses in specific populations. 12We adopt in this article some of Epidemiology's concepts and approaches, and instead of human population and diseases, we focus on a satellite population and its on-orbit anomalies and failures. A total of 168 satellites were analyzed in this work, and they have logged 968.5 years on orbit. We analyze an extensive database of geosynchronous satellite anomalies and failures (retrospective cohort study) and develop for each spacecraft subsystem a health scorecard synthesizing its track record of on-orbit failure events. We include results on the severity of the failure events in each subsystem's health scorecard (distribution and rates). We also provide for each subsystem its failure concentration ratio or the extent to which a single satellite in our population has experienced multiple failure events from the same subsystem. Next, having derived health scorecards for ten satellite subsystems identified in the database, we conduct a comparative analysis of the propensity and severity of failures between these subsystems. We identify for example several major subsystems driving on-orbit failure events, such as the Thruster/Fuel, the Solar Array, the Payload, and the Telemetry Tracking and Command (TTC) subsystems. In addition, we find that the Control Processor, the Mechanisms, and the Solar Array Deployment subsystems are sufficiently robust and contribute a minor share to the overall failure events on orbit. Furthermore, we find for example that while the attitude control subsystem and the Batteries exhibit roughly similar average failure rates, they have very different behaviors in terms of the severity of anomalies they experience: the former primarily failing “soft” (minor anomaly), whereas the latter, the batteries most often fail “hard” with major non-repairable degradations that affect operation of a satellite on a permanent basis. The results here provided should prove helpful to satellite manufacturers by allowing them to hone in on problematic subsystems that would benefit most from reliability improvements.
Organizational form and the consequences of highly leveraged transactions: Kroger's recapitalization and Safeway's LBO

Abstract This paper compares the leveraged recapitalization of Kroger Co. with the leveraged buyout of Safeway Stores. While both transactions dramatically increased leverage, Safeway's also altered managerial ownership, board composition, and executive compensation, while Kroger's did not. My analysis suggests that these differences in organizational form lead to large differences in post-HLT restructuring actions and value creation. I conclude that the improved incentive structure and increased monitoring provided by the LBO specialist at Safeway lead managers to generate cash in a more productive manner than the organizational structure employed by Kroger.
A parallel heuristic for quadratic assignment problems

Abstract The quadratic assignment problem represents an important class of problems with applications as diverse as facility layout and data analysis. The importance of these applications coupled with the fact that the quadratic assignment problem is NP-hard has encouraged the development of heuristics because optimal seeking procedures have been restricted to very small versions of the problem. This paper describes a new parallel heuristic, SAGA, for the quadratic assignment problem. SAGA is a cascaded hybrid of a genetic algorithm and simulated annealing. In addition to details regarding SAGA and its implementation, this paper also describes the performance of SAGA on two standard problems taken from the literature. The results from these problems show SAGA to be superior to the most commonly employed heuristic in solution quality, and for large problems it is also superior in solution time.
Simple and rapid quantification of the non-nucleoside reverse transcriptase inhibitors nevirapine, delavirdine, and efavirenz in human blood plasma using high-performance liquid chromatography with ultraviolet absorbance detection.

Abstract A simple reversed-phase high-performance liquid chromatography assay for the simultaneous quantitative determination of three HIV non-nucleoside reverse transcriptase inhibitors (nevirapine, delavirdine, and efavirenz) in human blood plasma is described. The method was validated over the range of 10 ng/ml to 50 μg/ml for nevirapine, 25 ng/ml to 25 μg/ml for delavirdine, and 10 ng/ml to 10 μg/ml for efavirenz. The method is accurate (average accuracies over eight concentrations ranging from 87.3 to 113%), and precise (within-day and between-day precision measures ranging from 0.12 to 7.9% and 0.26 to 5.9%, respectively). All three non-nucleoside reverse transcriptase inhibitors proved to be stable under various conditions. Due to its simplicity, this assay can readily be used for investigational or clinical monitoring of plasma concentrations.
Optimal Second-Stage Outsourcing

Manufacturers have recently begun outsourcing product assembly and completion tasks to their suppliers. Such outsourcing solves several contracting problems but generates new incentive frictions between manufacturers and their suppliers. In this paper, we analyze a manufacturer's decision to outsource an assembly (second-stage) task to a preestablished supplier. We find that outsourcing second-stage tasks becomes more attractive as the cost of either the first-or second-stage activity rises. Outsourcing becomes less attractive when the supplier is unable to accept large levels of liability. The manufacturer is shown to prefer more testing when she outsources assembly to her supplier as opposed to when she assembles products in house. Last, we find that the contracting frictions identified persist when the supplier's work can be tested individually, albeit imperfectly.
Mirabimides A–D, new N-acylpyrrolinones from the blue-green alga Scytonema mirabile

Abstract Mirabimide A, the major imide from the terrestrial blue-green alga Scytonema mirabile (Dillwyn) Bornet (strain BY-8-1), is N-[2-(N,N-dimethylleucyl)oxy-3-methylpentanoyl-N-methylvalyl-prolyl]-4-methoxy-5-isopropyl-3-pyrrolin-2-one. Mirabimides B–D are the valyl, 2-oxy-3-methylbutanoyl, and N-acetyl-N-methylleucyl analogs, respectively. The absolute configurations of the five asymmetric carbons in the mirabimides are proposed to be all S , but the assignments for the dimethylleucine units in A–C and the hydroxyacid units in B–D are tentative.
Notch-Filter Masks: Practical Image Masks for Planet-finding Coronagraphs

An ideal coronagraph with a band-limited image mask can efficiently image off-axis sources while removing identically all of the light from an on-axis source. However, strict mask construction tolerances limit the utility of this technique for directly imaging extrasolar terrestrial planets. We present a variation on the basic band-limited mask design—a family of "notch-filter" masks—that mitigates this problem. These robust and trivially achromatic masks can be easily manufactured by cutting holes in opaque material.
The capacity of the quantum depolarizing channel

The information-carrying capacity of the d-dimensional depolarizing channel is computed. It is shown that this capacity can be achieved by encoding messages as products of pure states belonging to an orthonormal basis of the state space, and using measurements which are products of projections onto this same orthonormal basis. In other words, neither entangled signal states nor entangled measurements give any advantage for information capacity. The result follows from an additivity theorem for the product channel /spl Delta//spl ominus//spl Psi/, where /spl Delta/ is the depolarizing channel and /spl Psi/ is a completely arbitrary channel. We establish the Amosov-Holevo-Werner(see Probl. Inform. Transm., vol.36, p.305-313, 2000) p-norm conjecture for this product channel for all p/spl ges/1, and deduce from this the additivity of the minimal entropy and of the Holevo quantity /spl chi//sup */.
Vaginal hysterectomy for the woman with a moderately enlarged uterus weighing 200 to 700 grams

Abstract Objectives: The purpose of this study was to compare the surgical outcomes of women with moderately enlarged uteri undergoing vaginal hysterectomy with those of women with uteri of normal size undergoing vaginal hysterectomy. A secondary objective was to investigate the roles of uterine morcellation and laparoscopically assisted vaginal hysterectomy in the treatment of these women. Study Design: Thirty consecutive women during a 2-year period with uterine enlargement to a weight of between 200 and 700 g underwent vaginal hysterectomy or laparoscopically assisted vaginal hysterectomy limited to lysis of adhesions or adnexectomy. These patients with uterine enlargement (group 1) were compared with 160 women with uteri weighing .99, 95% confidence interval –8.1% to 5.9%). Conclusions: Although vaginal hysterectomy requires a modest increase in operative time, it is as safe and effective for the woman with a moderately enlarged uterus as for the woman with a uterus of normal size. Vaginal uterine morcellation is the key to a successful operation and obviates the need for either abdominal or laparoscopically assisted hysterectomy solely to deal with moderate uterine enlargement. (Am J Obstet Gynecol 1999;180:1337-44.)
Stand reconstructed: Contingent closure and institutional change

The process is traced whereby crucially important, multiple denotations of classical sociology's key notion referring to social position—the Weberian German concept of Stand—have been stripped to create a simplified and inaccurate representation of social inequalities. Some historical material from central Europe is surveyed, with a brief look at Japan, to demonstrate validity problems created by blanket application of the culturally specific, streamlined notions of status/class. As an alternative, a notion of contingent social closure argues that relaxing the modernizationist assumptions of a single transition from estate to status/class increases the comparative-historical sensitivity of research on social structure, inequality, and stratification. A dynamic reading of Polanyi suggests a reconceptualization of institutions as the “raw material” of social change. This might help to avoid the outdated contrast of the “West” vs. its “Others.”
Synchrotron radiation damage observations in normal incidence copper mirrors

Abstract Water-cooled copper mirrors used at near-normal incidence on two beamlines at the NSLS are observed to undergo severe degradation upon exposure to the direct SR beam. These mirrors are used on beam lines designed to utilize radiation in the wavelength regions longer than 100 nm and are coated with a UV reflection-enhancing coating, consisting of one or more bilayers of aluminum with a MgF2 overcoat. Beamline performance degrades very rapidly following installation of a new set of mirrors. Analysis of the mirror surfaces by various non-destructive techniques indicates severe degradation of the coating and surface along the central strip where most of the X-ray power is absorbed from the beam. In one case where the mirror had three bilayer coatings, the outer coating layer has disappeared along the central strip. Rutherford backscatter measurements indicate compositional changes between layers and confirm the existence of a carbon deposit on the surface. Thermal modeling suggests that most of the damage is caused by direct photon interaction, since the temperature rise in the energy deposition region is small.
ESCHER-A Computer Program for the Determination of External Rotational Symmetry Numbers from Molecular Topology.

An algorithm for determining the external rotational symmetry number of a molecule from a SMILES1 string has been developed. ESCHER operates by first locating the center or centers of graphical symmetry for the molecule and the equivalence classes of atoms connected to the center or centers. The center(s) of graphical symmetry is the atom(s) which is(are) most symmetrical with respect to the connections to other atoms. These are then used to calculate the symmetry number, σ.
Notes from the Director, National Heart, Lung, and Blood Institute: NHLBI core values and shaping the 2007 budget.

With fiscal year 2007 well under way, we write to report on the status of our budget for the National Heart, Lung, and Blood Institute (NHLBI). As a result of a Congressional joint resolution, the NHLBI received an allocation of $2 918 808 000, which represents an increase of ≈1% over the comparable figure for fiscal year 2006. The NHLBI has a longstanding and powerful commitment to preserve and enhance investigator-initiated research and to develop and support new investigators. In these difficult times, the NHLBI’s top priorities will be to stay true to these core values. To accomplish this objective, we have developed a number of strategies to assist investigators in launching successful research careers and riding out tough times. Several policies are designed to ease the path to independence for new investigators (http://www.nhlbi.nih.gov/funding/policies/operguid.htm):
Discrete torsion, covering groups and quiver diagrams

Without recourse to the sophisticated machinery of twisted group algebras, projective character tables and explicit values of 2-cocycles, we here present a simple algorithm to study the gauge theory data of D-brane probes on a generic orbifold G with discrete torsion turned on. We show in particular that the gauge theory can be obtained with the knowledge of no more than the ordinary character tables of G and its covering group G*. Subsequently we present the quiver diagrams of certain illustrative examples of SU(3)-orbifolds which have non-trivial Schur Multipliers. The paper serves as a companion to our earlier work (arXiv:hep-th/0010023) and aims to initiate a systematic and computationally convenient study of discrete torsion.
Fragility and persistence of leafwise intersections

In this paper we study the question of fragility and robustness of leafwise intersections of coisotropic submanifolds. Namely, we construct a closed hypersurface and a sequence of Hamiltonians $$C^0$$ -converging to zero such that the hypersurface and its images have no leafwise intersections, showing that some form of the contact type condition on the hypersurface is necessary in several persistence results. In connection with recent results in continuous symplectic topology, we also show that $$C^0$$ -convergence of hypersurfaces, Hamiltonian diffeomorphic to each other, does not in general force $$C^0$$ -convergence of the characteristic foliations.
The Political Economy of Urban Land Reform in Hawaii

Summary. In the mid 1960s there were about 22 000 single-family leasehold homes in Honolulu. Dissatisfaction with leasehold led to reform legislation in 1967, allowing lessees to buy leased land. By 1991 less than 5000 lessees remained. This paper examines why landowners elected to lease rather than sell land and attributes the rise of leasehold to legal constraints on land sales by large estates, duties of estate trustees and the federal tax code. Ideological forces initiated land reform in 1967, but rent-seeking forces captured the process in the mid 1970s. It is concluded that Hawaii’s experiment with leasehold was a failure due to the dif® culties associated with specifying and enforcing long-term contracts in residential land.
Designing masking fault-tolerance via nonmasking fault-tolerance

Masking fault-tolerance guarantees that programs continually satisfy their specification in the presence of faults. By way of contrast, nonmasking fault-tolerance does not guarantee as much: it merely guarantees that when faults stop occurring, program executions converge to states from where programs continually (re)satisfy their specification. We present in this paper a component based method for the design of masking fault-tolerant programs. In this method, components are added to a fault-intolerant program in a stepwise manner, first, to transform the fault-intolerant program into a nonmasking fault-tolerant one and, then, to enhance the fault-tolerance from nonmasking to masking. We illustrate the method by designing programs for agreement in the presence of Byzantine faults, data transfer in the presence of message loss, triple modular redundancy in the presence of input corruption, and mutual exclusion in the presence of process fail-stops. These examples also serve to demonstrate that the method accommodates a variety of fault-classes. It provides alternative designs for programs usually designed with extant design methods, and it offers the potential for improved masking fault-tolerant programs.
How does a dipolar Bose-Einstein condensate collapse?

We emphasize that the macroscopic collapse of a dipolar Bose-Einstein condensate in a pancake-shaped trap occurs through local density fluctuations, rather than through a global collapse to the trap center. This hypothesis is supported by a recent experiment in a chromium condensate.
Materials for High-Energy Radiation Shielding on Extra-Terrestrial Surfaces

Polyethylene and polypropylene were used with simulated lunar regolith to make micro-composites as possible materials for habitat construction on extra-terrestrial surfaces. The polymer powders were used in various mass percents and thoroughly mixed with regolith powder before heating. A heated press or a microwave oven was used to heat the polymer/regolith mixture and form the micro-composite. The resulting materials were characterized by thermal analysis.
A new method for the preparation of 3,5-disubstituted butenolides

Abstract A convenient method for the transformation of suitably protected propargyl alcohols into 3,5disubstiuted butenolides has been developed. This organozirconium-based method transforms optically active propargyl alcohols into the corresponding butenolides with no loss of optical activity.
The Power of Nonmonotonicity in Geometric Searching

We define a close variant of line range searching over the reals and prove that its arithmetic complexity is ź(n log n) if field operations are allowed and ź(n3/2) if only additions are. This provides the first nontrivial separation between the monotone and nonmonotone complexity of a range searching problem. The result puts into question the widely held belief that range searching for nonisothetic shapes typically requires Ω(n1+c) arithmetic operations, for some constant c > 0.
Neutrinos and the supernova origin of the elements

Abstract Intense fluxes of neutrinos are emitted by the hot neutron star produced in a supernova. The average supernova neutrino energies satisfy a robust hierarchy 〈E ν e 〉 ν e 〉 ν μ(τ) 〉 ≈ 〈E ν μ(τ) 〉 . The νe and ν e capture reactions on neutrons and protons, respectively, provide heating to drive a wind from the hot neutron star. The same reactions also determine the neutron-richness of the wind material. Nucleosynthesis via rapid neutron capture, the r-process, may occur in the wind material as it expands away from the neutron star. The neutron-richness of the wind material, and hence, the r-process nucleosynthesis therein, are sensitive to mixing between ν μ(τ) ν μ(τ) and νeνe (or sterile neutrinos ν s ν s ) at the level of sin2 2θ ⪅ 10−4 for δm 2 ⪆ 1 eV 2 . Indirect arguments and direct tests for the supernova origin of the r-process elements are discussed with a goal to establish supernova r-process nucleosynthesis as an important probe for neutrino mixing.
Coulomb corrections to e+e− production in ultra-relativistic nuclear collisions

Abstract The purpose of this paper is to explain the discrepancies existing in the literature relative to e + e − pair production in peripheral heavy ion collisions at ultra-relativistic energies. A controversial issue is the possible cancellation of Coulomb corrections to the Born term in the pair production cross-section. Such a cancellation has been observed in a recent approach based on finding retarded solutions of the Dirac equation, but does not seem to hold in a perturbative approach. We show in this paper that the two approaches are in fact calculating different observables: the perturbative approach gives the exclusive cross-section of single pair production, while the other method gives the inclusive cross-section. We have also performed a thorough study of the electron propagator in the non-static background field of the two nuclei, the conclusion of which is that the retarded propagator is in the ultra-relativistic limit a much simpler object than the Feynman propagator, and can be calculated exactly.