cssi/SciSciGPT-SciSciNet huggingface dataset:
Vertex Algebras and the Class Algebras of Wreath Products

The Jucys?Murphy elements for wreath products $\Gamma_n = \Gamma \wr S_n $ associated to any finite group $\Gamma$ are introduced and they play an important role in our study of the connections between class algebras of $\Gamma_n$ for all $n$ and vertex algebras. We construct an action of (a variant of) the $\mathcal W_{1 + \infty}$-algebra acting irreducibly on the direct sum ${\mathcal R}_\Gamma$ of the class algebras of $\Gamma_n$ for all $n$ in a group-theoretic manner. We establish various relations between convolution operators using JM elements and Heisenberg algebra operators acting on ${\mathcal R}_\Gamma$. As applications, we obtain two distinct sets of algebra generators for the class algebra of $\Gamma_n$ and establish various stability results concerning products of normalized conjugacy classes of $\Gamma_n$ and the power sums of Jucys--Murphy elements, etc. We introduce a stable algebra which encodes the class algebra structures of $\Gamma_n$ for all $n$, whose structure constants are shown to be non-negative integers. In the symmetric group case (that is, when $\Gamma$ is trivial), we recover and strengthen in a uniform approach various results of Lascoux and Thibon, Kerov and Olshanski, and Farahat and Higman, etc.
The Alloy Theoretic Automated Toolkit: A User Guide

Although the formalism that allows the calculation of alloy thermodynamic properties from first-principles has been known for decades, its practical implementation has so far remained a tedious process. The Alloy Theoretic Automated Toolkit (ATAT) drastically simplifies this procedure by implementing decision rules based on formal statistical analysis that frees the researchers from a constant monitoring during the calculation process and automatically “glues” together the input and the output of various codes, in order to provide a high-level interface to the calculation of alloy thermodynamic properties from first-principles. ATAT implements the Structure Inversion Method (SIM), also known as the Connolly-Williams method, in combination with semi-grand-canonical Monte Carlo simulations. In order to make this powerful toolkit available to the wide community of researchers who could benefit from it, this article present a concise user guide outlining the steps required to obtain thermodynamic information from ab initio calculations.
The representation problem and the efficiency of the price mechanism

Abstract It is shown in this paper that the way in which an allocation is represented (net trades, final allocation, etc.) can affect the design of any realizing mechanism or incentive compatible system. The reason is that a poor choice of representation may be imposing superfluous conditions and demands upon the realizing mechanism. So, in this paper a technique is developed to (1) find the optimal representation of an allocation, and (2) to characterize the associated, realizing mechanisms. Although this approach is designed to be applied to any smooth economic model, it is illustrated and motivated here by applying it to the price mechanism. More specifically, there are assertions in the literature by Mount and Reiter and by Hurwicz that the price mechanism is informationally efficient over the class of Pareto seeking mechanisms. These proofs are incomplete because they consider only one choice of representation for the Pareto allocations. We use this technique to (a) reassert the dimensional efficiency of the price mechanism, (b) compare mechanisms for spaces of economics with and without externalities, (c) characterize for the space of quadratic functions the other dimensionally efficient allocation concepts, and (d) characterize those two agent economics where the price mechanism is dimensionally efficient.
Modular forms on noncongruence subgroups and Atkin-Swinnerton-Dyer relations

We give new examples of noncongruence subgroups Γ ⊂ SL2(ℤ) whose space of weight-3 cusp forms S 3(Γ) admits a basis satisfying the Atkin–Swinnerton-Dyer congruence relations with respect to a weight-3 newform for a certain congruence subgroup.
Neutrino Properties and Tests of Symmetries

The fact that neutrinos have mass allows them to possess many other properties, like a magnetic dipole moment and a finite decay width. Theoretical expectations for these are, however, well beyond current experimental bounds, and the discovery of new exotic neutrino properties would indicate the presence of (more) new physics. Here, I review some of the current bounds on exotic neutrino properties. Neutrino experiments are unique probes of several fundamental space-time symmetries, including invariance under CP and Lorentz transformations. I discuss how precision neutrino experiments are used to test some of the most fundamental principles of physics at unprecedented levels.
Symmetry relations for heavy-to-light meson form factors at large recoil

The description of large-recoil heavy-to-light meson form factors is reviewed in the framework of soft-collinear effective theory. At leading power in the heavy-quark expansion, three classes of approximate symmetry relations arise. The relations are compared to experimental data for D → K* and Ds → φ form factors, and to light-cone QCD sum rule predictions for B → π and B → ρ form factors. Implications for the extraction of |Vub| from semileptonic B → ρ decays are discussed.
Comparison of CFD and theoretical post-shock gradients in hypersonic flow

Abstract In the recent work of Prof. Hans Hornung, expressions for the gradients of flow properties immediately behind a curved shock wave were obtained for a reacting gas [1] . In this paper, I use the expressions derived by Hornung to compare with inviscid computational fluid dynamics simulations of a Mach 8 flow over a cylinder. A finite-rate vibrational relaxation model is used to simplify the comparisons with theory. The shape of the bow shock wave is extracted from the CFD results, fitted with a polynomial, and then used to compute the post-shock gradients of the main flow variables. It is found that in general the CFD results are in very good agreement with the theory for both perfect gas and vibrationally relaxing flows. There are some notable differences, mostly centered on the location of the change in sign of the post-shock density gradient; this quantity is found to be highly sensitive to the relaxation rate of the gas. The theoretical post-shock gradients provide a rigorous test of CFD and suggest possible experiments that would be a very sensitive test of the models of finite-rate vibrational and chemical processes.
A Dynamic Model of Oligopoly in the Coffee Export Market

A linear-quadratic, dynamic feedback oligopoly model that nests various market structures is used to estimate the degree of competitiveness and the adjustment paths of the two largest coffee exporters, Brazil and Colombia. Their estimated behavior is relatively competitive. This subgame perfect dynamic model is-compared to a standard static oligopoly model and the open-loop model (the dynamic generalization of the standard static model). Both classical and Bayesian tests of open-loop and feedback dynamic models are reported.
Physical topology design for survivable routing of logical rings in WDM-based networks

In a wavelength-division multiplexed (WDM)-based network, a single physical link failure may correspond to multiple logical link failures. As a result, two-connected logical topologies, such as rings routed on a WDM physical topology, may become disconnected after a single physical link failure. We consider the design of physical topologies that ensure logical rings can be embedded in a survivable manner. This is of particular interest in metropolitan area networks, where logical rings are in practice almost exclusively employed for providing protection against link failures. First, we develop necessary conditions for the physical topology to be able to embed all logical rings in a survivable manner. We then use these conditions to provide tight bounds on the number of physical links that an N-node physical topology must have in order to support all logical rings for different sizes K. We show that when K/spl ges/4 the physical topology must have at least 4N/3 links, and that when K/spl ges/6 the physical topology must have at least 3N/2 links. Subsequently, we generalize this bound for all K/spl ges/4. When K/spl ges/N-2, we show that the physical topology must have at least 2N-4 links. Finally, we design physical topologies that meet the above bounds for both K=4 and K=N-2. Specifically, our physical topology for embedding (N-2)-node rings has a dual hub structure and is able to embed all rings of size less than N-1 in a survivable manner. We also provide a simple extension to this topology that addresses rings of size K=N-1 and rings of size K=N for N odd. We observe that designing the physical topology for supporting all logical rings in a survivable manner does not use significantly more physical links than a design that only supports a small number of logical rings. Hence, our approach of designing physical topologies that can be used to embed all possible ring logical topologies does not lead to a significant overdesign of the physical topology.
Ultrathin Organic Films Grown by Organic Molecular Beam Deposition and Related Techniques.

During the past decade, enormous progress has been made in growing ultrathin organic films and multilayer structures with a wide range of exciting optoelectronic properties. This progress has been made possible by several important advances in our understanding of organic films and their modes of growth. Perhaps the single most important advance has been the use of ultrahigh vacuum (UHV) as a means to achieve, for the first time, monolayer control over the growth of organic thin films with extremely high chemical purity and structural precision.1-3 Such monolayer control has been possible for many years using well-known techniques such as Langmuir-Blodgett film deposition,4 and more recently, self-assembled monolayers from solution have also been achieved.5 However, ultrahighvacuum growth, sometimes referred to as organic molecular beam deposition (OMBD) or organic molecular beam epitaxy (OMBE), has the advantage of providing both layer thickness control and an atomically clean environment and substrate. When combined with the ability to perform in situ highresolution structural diagnostics of the films as they are being deposited, techniques such as OMBD have provided an entirely new prospect for understanding many of the fundamental structural and optoelectronic properties of ultrathin organic film systems. Since such systems are both of intrinsic as well as practical interest, substantial effort worldwide has been invested in attempting to grow and investigate the properties of such thin-film systems. This paper is a review of recent progress made in organic thin films grown in ultrahigh vacuum or using other vapor-phase deposition methods. We will describe the most important work which has been published in this field since the emergence of OMBD in the mid-1980s. Both the nature of thin-film growth and structural ordering will be discussed, as well as some of the more interesting consequences to the physical properties of such organic thin-film systems will be considered both from a theoretical as well as an experimental viewpoint. Indeed, it will 1793 Chem. Rev. 1997, 97, 1793−1896
Monetary General Equilibrium With Transaction Costs

Abstract Commodity money arises endogenously in a general equilibrium model with separate budget constraints for each transaction. Transaction costs imply differing bid and ask (selling and buying) prices. The most liquid good—with the smallest proportionate bid/ask spread—becomes commodity money. General equilibrium may not be Pareto efficient. If zero-transaction-cost money is available then the equilibrium allocation is Pareto efficient. Fiat money is an intrinsically worthless instrument. Its positive price comes from acceptability in paying taxes, and its use as a medium of exchange is based on low transaction cost.
Proximity and Investment: Evidence from Plant-Level Data*

Proximity to plants makes it easier for headquarters to monitor and acquire information about plants. In this article, I estimate the effects of headquarters’ proximity to plants on plant-level investment and productivity. Using the introduction of new airline routes as a source of exogenous variation in proximity, I find that new airline routes that reduce the travel time between headquarters and plants lead to an increase in plant-level investment of 8% to 9% and an increase in plants’ total factor productivity of 1.3% to 1.4%. The results are robust when I control for local and firm-level shocks that could potentially drive the introduction of new airline routes, when I consider only new airline routes that are the outcome of a merger between two airlines or the opening of a new hub, and when I consider only indirect flights where either the last leg of the flight (involving the plant’s home airport) or the first leg of the flight (involving headquarters’ home airport) remains unchanged. Moreover, the results are stronger in the earlier years of the sample period and for firms whose headquarters is more time-constrained. In addition, they also hold at the extensive margin, that is, when I consider plant openings and closures.
Load-displacement measurement and work determination in three-point bend tests of notched or precracked specimens

Suggestions for testing of notched or cracked three-point bend specimens are presented that (1) correct displacement measurement errors resulting from misalignment between the load applicator and specimen; (2) account for coincidental strains not associated with the work of crack extension; (3) simplify record analysis and processing; and (4) extend displacement gage range without sacrifice of sensitivity or accuracy. These testing details are particularly applicable to procedures in which the crack extension force J(I) is determined from the work done on the specimen.
Spin-resolved self-doping tunes the intrinsic half-metallicity of AlN nanoribbons

We present a first-principles theoretical study of electric field-and straincontrolled intrinsic half-metallic properties of zigzagged aluminium nitride (AlN) nanoribbons. We show that the half-metallic property of AlN ribbons can undergo a transition into fully-metallic or semiconducting behavior with application of an electric field or uniaxial strain. An external transverse electric field induces a full charge screening that renders the material semiconducting. In contrast, as uniaxial strain varies from compressive to tensile, a spin-resolved selective self-doping increases the half-metallic character of the ribbons. The relevant strain-induced changes in electronic properties arise from band structure modifications at the Fermi level as a consequence of a spin-polarized charge transfer between p-orbitals of the N and Al edge atoms in a spin-resolved self-doping process. This band structure tunability indicates the possibility of designing magnetic nanoribbons with tunable electronic structure by deriving edge states from elements with sufficiently different localization properties. Finite temperature molecular dynamics reveal a thermally stable half-metallic nanoribbon up to room temperature.
Thiol-Reactive Derivatives of the Solvatochromic 4-N,N-Dimethylamino-1,8-naphthalimide Fluorophore: A Highly Sensitive Toolset for the Detection of Biomolecular Interactions

The solvatochromic fluorophore 4-N,N-dimethylamino-1,8-naphthalimide (4-DMN) possesses extremely sensitive emission properties due largely to the low intrinsic fluorescence it exhibits in polar protic solvents such as water. This makes it well suited as a probe for the detection of a wide range of biomolecular interactions. Herein we report the development and evaluation of a new series of thiol-reactive agents derived from this fluorophore. The members of this series vary according to linker type and the electrophilic group required for the labeling of proteins and other biologically relevant molecules. Using the calcium-binding protein calmodulin as a model system, we compare the performance of the 4-DMN derivatives to that of several commercially available solvatochromic fluorophores identifying many key factors important to the successful application of such tools. This study also demonstrates the power of this new series of labeling agents by yielding a fluorescent calmodulin construct capable of producing a greater than 100-fold increase in emission intensity upon binding to calcium.
Environmental Policy Attitudes: Issues, Geographical Scale, and Political Trust*

Objectives. This article examines environmental policy attitudes, focusing on the differences in preferences across issue type (i.e., pollution, resource preservation) and geographical scale (i.e., local, national, global). In addition, we study whether an individual’s trust in government influences environmental policy attitudes. Methods. Analyzing data from the 2007 Cooperative Congressional Election Study, we estimate a series of OLS regression models to examine the public’s environmental policy attitudes. Results. We find stronger public support for government action to address pollution issues than resources issues, and stronger support for local and national pollution abatement than dealing with global problems. We also find that Republicans and ideological conservatives are less likely to support further government effort to address the environment, and that more trusting individuals are more favorable to government action to address pollution and global issues. Conclusion. Environmental policy attitudes vary by the nature of the issue; however, political ideology and partisan affiliation are consistent predictors of preferences across issues, even when controlling for an individual’s level of trust in government. Since the onset of the modern environmental movement more than three decades ago, social scientists have actively examined public opinion on the environment. Recent research suggests that the U.S. public has persistently expressed concern about environmental problems (Dunlap, 2002; Guber, 2003). The General Social Survey, for example, has routinely asked the public whether the federal government is spending the right amount of money on improving and protecting the environment. For most of the past 30 years, majorities of the public (ranging from 50 percent to 60 percent) have responded that the federal government is spending too little. The apex
Field-dependent AC susceptibility of itinerant ferromagnets

Whereas dc measurements of magnetic susceptibility, χ, fail to distinguish between local and weak itinerant ferromagnets, radio-frequency (rf) measurements of χ in the ferromagnetic state show dramatic differences between the two. We present sensitive tunnel-diode resonator measurements of χ in the weak itinerant ferromagnet ZrZn2 at a frequency of 23 MHz. Below the Curie temperature, TC≈26 K, the susceptibility is seen to increase and pass through a broad maximum at approximately 15 K in zero applied dc magnetic field. Application of a magnetic field reduces the amplitude of the maximum and shifts it to lower temperatures. The existence and evolution of this maximum with applied field is not predicted by either the Stoner or self-consistent renormalized (SCR) spin-fluctuation theories. For temperatures below TC both theories derive a zero-field limit expression for χ. We propose a semi-phenomenological model that considers the effect of the internal field from the polarized fraction of the conduction band on the remaining, unpolarized conduction band electrons. The developed model accurately describes the experimental data.
Learning to place new objects in a scene

Placing is a necessary skill for a personal robot to have in order to perform tasks such as arranging objects in a disorganized room. The object placements should not only be stable but also be in their semantically preferred placing areas and orientations. This is challenging because an environment can have a large variety of objects and placing areas that may not have been seen by the robot before. In this paper, we propose a learning approach for placing multiple objects in different placing areas in a scene. Given point-clouds of the objects and the scene, we design appropriate features and use a graphical model to encode various properties, such as the stacking of objects, stability, object-area relationship and common placing constraints. The inference in our model is an integer linear program, which we solve efficiently via an linear programming relaxation. We extensively evaluate our approach on 98 objects from 16 categories being placed into 40 areas. Our robotic experiments show a success rate of 98% in placing known objects and 82% in placing new objects stably. We use our method on our robots for performing tasks such as loading several dish-racks, a bookshelf and a fridge with multiple items.
Hindsight/Foresight: The Effect of Outcome Knowledge on Judgment Under Uncertainty

One major difference between historical and nonhistorical judgment is that the historical judge typically knows how things turned out. In Experiment 1, receipt of such outcome knowledge was found to increase the postdicted likelihood of reported events and change the perceived relevance of event descriptive data, regardless of the likelihood of the outcome and the truth of the report. Judges were, however, largely unaware of the effect that outcome knowledge had on their perceptions. As a result, they overestimated what they would have known without outcome knowledge (Experiment 2), as well as what others (Experiment 3) actually did know without outcome knowledge. It is argued that this lack of awareness can seriously restrict one's ability to judge or learn from the past.
Tuning solvent-dependent color changes of three-dimensionally ordered macroporous (3DOM) materials through compositional and geometric modifications

Striking color changes in the visible spectrum are produced when the voids of three-dimensionally ordered macroporous (3DOM) silica, alumina, and zirconia ("inverse opals") are filled with solvents, it is reported here (see Figure). The wavelength of these colors is linearly related to the refractive index of the fluid filling the pores and can be tuned by modifying the refractive index of the wall material as well as the size and spacing of the pores.
Scalable Synthesis of Morphotropic Phase Boundary Lead Zirconium Titanate Nanowires for Energy Harvesting

Lead zirconium titanate (PZT) nanowires are synthesized using a scalable two-step hydrothermal reaction. The piezo-electric coupling coefficient of the PZT NWs shows the highest value for PZT nano-wires in the literature (80 ± 5 pm/V). A PZT-NW-based nanocomposite is fabri-cated to demonstrate an energy-harvesting application with an open-circuit voltage up to 7 V and a power density up to 2.4 μW/cm(3) .
On list update and work function algorithms

The list update problem, a well-studied problem in dynamic data structures, can be described abstractly as a metrical task system. In this paper, we prove that a generic metrical task system algorithm, called the work function algorithm, has constant competitive ratio for list update. In the process, we present a new formulation of the well-known "list factoring" technique in terms of a partial order on the elements of the list. This approach leads to a new simple proof that a large class of online algorithms, including Move-To-Front, is (2 - 1/k)-competitive, for k the list length.
The jet propulsion laboratory ephemeris tape system

Predictions of the motion of celestial bodies can be presented in tabular form. These tables, called ephemerides, list position as a function of time. Positions at any time point within the range of the table can be obtained by interpolation.
Strong Support for Weak Performance: Donor Competition in Madagascar

Since independence, Madagascar's ability to meet its development and environmental goals has remained weak. Yet Madagascar has never suffered a shortage of foreign assistance. What explains such a paradox? This article argues that the gap between foreign aid and development performance is rooted in donor competition to give aid for the purpose of advancing their foreign interests. In turn, the state exploits this donor competition to stay afloat. This process of exploiting aid creates a situation of mutual dependency between donors and the state. This is a departure from theories that attribute poor performance solely to recipient countries’ aid dependency. The article examines state-donor relations in Madagascar's environmental sector in the past two decades. It suggests that influencing government policies (for donors) and resource capture and redistribution (for the state), rather than conservation per se, are the de facto goals of conservation politics. It then assesses the extent to which the dynamics of conservation politics apply beyond this specific arena. It concludes that what disables successful conservation and the development it should enable is neither the volume nor type of foreign aid but the absence of institutions that effectively align donor and state incentives with strong development performance.
Sky Surface Brightness at Mount Graham: UBVRI Science Observations with the Large Binocular Telescope

We present the measurements of sky surface brightness on Mount Graham International Obser- vatory obtained during the first binocular-mode science runs at the Large Binocular Telescope (LBT). A total of 860 images obtained on 23 moonless nights during the period February 2008-June 2008 were analyzed with our data quality assessment procedure. These data, taken at the solar minimum, show that Mt. Graham, in photometric con- ditions, still has one of the darkest skies, competing with the other first-class observatories. The zenith-corrected values are 21.98, 22.81, 21.81, 20.82, and 19:78 magarcsec � 2 in U, B, V, R, and I, respectively. In photometric conditions, the sky background is ∼0:1 magarcsec � 2 higher than the median when observing toward Tucson and Phoenix. but it may be up to ∼0:5 magarcsec � 2 higher in nonphotometric conditions. The sky at Mt. Graham is ∼0:32 magarcsec � 2 brighter at air mass ∼1:4 than at zenith, but no significant trend was found with the time of night. We demonstrated the dependence of the sky background at Mt. Graham on the solar activity for the first time. In fact, in 2008, at B and V bands, the sky was ∼0:3 magarcsec � 2 darker than in 1999-2002. With these results, we conclude that Mt. Graham is still a first-class observing site, comparable to the darkest sites in Hawaii, Chile, and the Canary Islands.
Determinants of cross-border merger premia

Firms have a broad range of rationales for engaging in cross-border mergers and other forms of foreign direct investment (FDI); while some companies are in search of the cost advantages provided by foreign resources, other firms are primarily interested in gaining access to new markets. Although a significant amount of research has explored the patterns of FDI, little work has been done to assess what influences the value of cross-border mergers and, in particular, what determines why some cross-border mergers are expected to result in higher synergies when compared to others. This paper explores what characteristics of a merger are expected to increase the synergies that a firm will accrue from a cross-border merger by testing how a variety of factors impact the premia paid to effectuate a cross-border merger. We find that firms are willing to pay a higher premium to obtain greater control over foreign firms, and that this control is even more important in mergers involving firms in emerging markets. We also find that the factors affecting deal premia in cross-border mergers differ based on whether the acquirer has a high or low intangible asset intensity level.
The First Enantioselective Organocatalytic Mukaiyama−Michael Reaction: A Direct Method for the Synthesis of Enantioenriched γ-Butenolide Architecture

The first enantioselective organocatalytic Mukaiyama−Michael reaction using α,β-unsaturated aldehydes has been accomplished. The use of iminium catalysis has provided a new strategy for the enantioselective addition of 2-silyloxy furans to unsaturated aldehydes to generate a variety of butenolide systems, an important chiral synthon found among many natural isolates. The (2S,5S)-5-benzyl-2-tert-butyl-imidazolidinone amine catalyst has been found to mediate the conjugate addition of a wide variety of substituted and unsubstituted silyloxy furans to unsaturated aldehydes. A diverse range of aldehyde substrates can be accommodated in this new organocatalytic transformation. Application of this new asymmetric technology to the enantioselective total synthesis of spiculisporic acid and the corresponding 5-epi-spiculisporic acid analogue is also discussed.
Heparin protects against septic mortality via apoE-antagonism

Abstract Background Apolipoprotein E (apoE), a component of plasma lipoproteins, increases septic mortality in a rodent model of sepsis, presumably by enhancing lipid antigen presentation to antigen-presenting cells via the low-density lipoprotein receptor (LDLR). Downstream, this culminates in natural killer T (NKT) cell activation and cytokine secretion. To determine whether apoE antagonism would protect against septic mortality in mice, apoE-LDLR binding was antagonized using heparin, which can inhibit apoE's LDLR-binding site. Methods C57BL/6 mice underwent cecal ligation and puncture (CLP) and heparin infusion. Serum partial thromboplastin time and alanine aminotransferase were measured at 24 hours, and survival was monitored for 7 days after CLP. LDLR+/+ and LDLR−/− fibroblasts were incubated with apoE and heparin to measure apoE internalization. Hepatic NKT cells and cytokine levels were quantified via fluorescence-activated cell sorting. Results Heparin decreased CLP–induced mortality by 50% versus saline-treated controls, independent of anticoagulation. LDLR+/+ fibroblasts displayed decreased uptake of apoE when treated concurrently with heparin for 12 hours. In septic mice, hepatic alanine aminotransferase levels, hepatic NKT cells, and plasma cytokine levels decreased after heparin treatment. Conclusions This study demonstrates that heparin protects against septic mortality independent of its anticoagulant effect. This protective effect is associated with the inhibition of apoE-LDLR binding, diminished NKT proliferation and cytokine production, and hepatic dysfunction. These findings indicate a potential clinical role for apoE antagonism in the treatment of sepsis.
A FUNCTORIAL APPROACH TO THE C*-ALGEBRAS OF A GRAPH

A functor from the category of directed trees with inclusions to the category of commutative C*-algebras with injective *-homomorphisms is constructed. This is used to define a functor from the category of directed graphs with inclusions to the category of C*-algebras with injective *-homomorphisms. The resulting C*-algebras are identified as Toeplitz graph algebras. Graph algebras are proved to have inductive limit decompositions over any family of subgraphs with union equal to the whole graph. The construction is used to prove various structural properties of graph algebras.
ACETYLIDE ANIONS EXERT COMPLETE CONTROL OVER ALDOLIZATION DURING THE DIRECT CONVERSION OF SQUARATE ESTERS INTO POLYQUINANES

Abstract The sequential condensation of diisopropyl squarate with a vinyl anion and a lithium acetylide triggers a cascade of mechanistic events that eventuates in formation of highly functionalized unsaturated diquinanes.
Software processes are software too

The major theme of this meeting is the exploration of the importance of process as a vehicle for improving both the quality of software products and the way in which we develop and evolve them. In beginning this exploration it seems important to spend at least a short time examining the nature of process and convincing ourselves that this is indeed a promising vehicle.
Quartic K3 surfaces without nontrivial automorphisms

For any field k we fix an algebraic closure of k, denoted by k. For a variety X ⊂ P k we set X = X×k k, we say that X is smooth if X is regular, and we let AutX denote the group of k-automorphisms of X, while LinX denotes the group of linear automorphisms of X, i.e., automorphisms induced by a linear transformation of the coordinates of P. The following theorem was proved by Poonen, see [Po], Thm. 1.6.
Promotion of lens epithelial-fiber differentiation by the C-terminus of connexin 45.6 – a role independent of gap junction communication

We previously reported that, among the three connexins expressed in chick lens, overexpression of connexin (Cx) 45.6, not Cx43 or Cx56, stimulates lens cell differentiation; however, the underlying mechanism responsible for this effect is unclear. Here, we took advantage of naturally occurring loss-of-gap-junction function mutations of Cx50 (ortholog of chick Cx45.6) and generated the corresponding site mutants in Cx45.6: Cx45.6(D47A) and Cx45.6(P88S). In contrast to wild-type Cx45.6, the mutants failed to form functional gap junctions, and Cx45.6(P88S) and, to a lesser degree, Cx45.6(D47A) functioned in a dominant-negative manner. Interestingly, overexpression of both mutants incapable of forming gap junctions significantly increased epithelial-fiber differentiation to a level comparable to that of wild-type Cx45.6. To map the functional domain of Cx45.6, we generated a C-terminus chimera as well as deletion mutants. Overexpression of Cx56*45.6C, the mutant in which the C-terminus of Cx56 was replaced with that of Cx45.6, had a stimulatory effect on lens cell differentiation similar to that of Cx45.6. However, cells overexpressing Cx45.6*56C, the mutant in which C-terminus of Cx45.6 was replaced with that of Cx56, and Cx45.6(–C), in which the C-terminus was deleted, failed to promote differentiation. Taken together, we conclude that the expression of Cx45.6, but not Cx45.6-dependent gap junction channels, is involved in lens epithelial-fiber cell differentiation, and the C-terminal domain of Cx45.6 plays a predominant role in mediating this process.
Noise Trading and Exchange Rate Regimes

Policy-makers often justify their choice of fixed exchange rate regimes as a shelter against nonfundamental influences in the foreign exchange market. This paper proposes a framework, based on endogenous noise trading, which makes sense of the policy-makers' view. We show that as a result of multiple equilibria, the model violates Mundell's "Incompatible Trinity:" under some conditions, it is possible to reduce the volatility of the exchange rate without any sacrifice in terms of monetary autonomy. We provide empirical evidence supportive of the existence of a nonfundamental channel in the link between exchange rate regimes and exchange rate volatility. If … markets come to believe exchange rate stability is not itself a significant policy objective, we should not be surprised that snowballing cumulative movements can develop that appear widely out of keeping with current balance-of-payments prospects or domestic price movements. At that point, freely floating exchange rates, instead of delivering on the promise of money autonomy for domestic monetary or other policies, can greatly complicate domestic economic management [Paul Volcker 1978–79, p. 9].
The Effects of Consumer-Directed Health Plans on Health Care Spending

We use unique data from an insurer that exclusively offers high-deductible, "consumer-directed" health plans to identify the effect of plan features, no tably employer contributions to the spending account, on health care spend ing. Our results show that the marginal dollar contributed by the employer to the spending account is entirely spent on outpatient and pharmacy ser vices. In contrast, out-of-pocket spending was not responsive to the amount the employer contributes to the spending account. Our results represent the first plausibly causal estimates of the components of consumer-driven health plans on health spending. The magnitudes of the effects suggest im portant health care spending consequences to higher employer contributions to spending accounts. Our findings are most directly relevant to health re imbursement arrangement plan designs, though our results are still of value to health savings account plan designs.
On deterministic sketching and streaming for sparse recovery and norm estimation

We study classic streaming and sparse recovery problems using deterministic linear sketches, including l1/l1 and l ∞ /l1 sparse recovery problems, norm estimation, and approximate inner product. We focus on devising a fixed matrix A ∈ ℝ m×n and a deterministic recovery/estimation procedure which work for all possible input vectors simultaneously. We contribute several improved bounds for these problems. A proof that l ∞ /l1 sparse recovery and inner product estimation are equivalent, and that incoherent matrices can be used to solve both problems. Our upper bound for the number of measurements is m = O(e − 2 min {logn, (logn / log(1/e))2}). We can also obtain fast sketching and recovery algorithms by making use of the Fast Johnson-Lindenstrauss transform. Both our running times and number of measurements improve upon previous work. We can also obtain better error guarantees than previous work in terms of a smaller tail of the input vector. A new lower bound for the number of linear measurements required to solve l1/l1 sparse recovery. We show Ω(k/e 2 + klog(n/k)/e) measurements are required to recover an x′ with ∥ x − x′ ∥ 1 ≤ (1 + e) ∥ x tail(k) ∥ 1, where x tail(k) is x projected onto all but its largest k coordinates in magnitude. A tight bound of m = Θ(e − 2log(e 2 n)) on the number of measurements required to solve deterministic norm estimation, i.e., to recover ∥ x ∥ 2 ±e ∥ x ∥ 1. For all the problems we study, tight bounds are already known for the randomized complexity from previous work, except in the case of l1/l1 sparse recovery, where a nearly tight bound is known. Our work thus aims to study the deterministic complexities of these problems.
Effect of contrast enhancement on measurement of carotid artery intimal medial thickness

Previous studies have used standard B-mode ultrasound to quantify the aggregate mean intimal medial thickness (IMT) of the near and far wall of the common carotid artery (CCA). Many investigators have had dife culty in accurately evaluating the near wall IMT second- ary to dife culty in discerning the vessel lumen and intima. The purpose of this study is to deter- mine the effect of contrast enhanced ultrasound on IMT measurement when compared with non-enhanced images. Twenty-six patients who had standard carotid ultrasounds completed over a 6-month period were evaluated, with 24 imaged by the same sonographer. Five to six measurements of the near and far walls were obtained over a 1cm distance, beginning and end- ing 0.5cm and 1.5cm proximal to the carotid bifurcation. The measurements were made with and without the contrast agent Optison TM (pere utren protein type-A microspheres), which was given as an IV bolus (0.5 i0.7 cc). Of those imaged by the same sonographer, 40 carotid arteries were examined and a total of 867 measurements were obtained. A total of 10 % of the carotid ultrasounds were restudied approximately 1 month after the initial interpretation to assess observer accuracy. The near wall CCA mean (SD) IMT was 0.075 (0.019)cm for left with contrast versus 0.067 (0.023)cm for left without contrast and 0.089 (0.024)cm for right with versus 0.071 (0.022)cm for right without, p 0.0001 both sides. For the far wall of the CCA, the mean (SD) IMT comparison was 0.075 (0.021)cm for left with versus 0.070 (0.016)cm for left without, p ˆ 0.005, and 0.070 (0.023)cm for right with versus 0.070 (0.016)cm for right without, p ˆ 0.68. In conclusion, contrast-enhanced IMT measurement showed a highly statistically sig- nie cant difference in near carotid wall thickness determinations versus non-contrast values. The thicker measurement is in agreement with previously reported data showing that non-contrast images underestimated near wall common carotid IMT in histologic samples.
Correction magnet power supplies for APS machine

The Advanced Photon Source (APS) machine requires a number of correction magnets; five kinds for the storage ring, two for the injector synchrotron, and two for the positron accumulator ring. Three types of bipolar power supply will be used for all the correction magnets. The author describes the design aspects and considerations for correction magnet power supplies for the APS machine. The circuit configuration and control aspects are discussed. The drive requirements for the power semiconductors are described. The protection systems are outlined. >
Preparation of alkylation agents for bulged DNA microenvironments

A designed molecule with capacity to alkylate DNA bulges has been prepared from readily available starting materials. The spirocyclic template utilized was designed on the basis of established architectures, and equipped with a mustard alkylating group. Preliminary studies confirm alkylation of specific bulged sequences, paving the way for second generation substrates with higher affinity.
Resolved Motion Rate Control of Manipulators and Human Prostheses

The kinematics of remote manipulators and human prostheses is analyzed for the purpose of deriving resolved motion rate control. That is, the operator is enabled to call for the desired hand motion directly along axes relevant to the task environment. The approach suggests solutions to problems of coordination, motion under task constraints, and appreciation of forces encountered by the controlled hand.
Diastereoselective aldol reactions of β-silyloxy ethyl ketones. Application to the total synthesis of bafilomycin A1

Studies directed toward the C17C18 aldol bond construction in the macrolide antibiotic bafilomycin A1 are described. The effect of the β-substituent in the aldol reactions of α-unsubstituted enolates is documented for various model compounds. The stereoselectivity of this process is critically dependent on the C21 and C23 oxygen protecting groups. Application of this methodology to the synthesis of bafilomycin A1 is reported.
Synthesis and Characterization of a Remarkable Ceramic: Ti3SiC2

Polycrystalline bulk samples of Ti{sub 3}SiC{sub 2} were fabricated by reactively hot-pressing Ti, graphite, and SiC powders at 40 MPa and 1,600 C for 4 h. This compound has remarkable properties. Its compressive strength, measured at room temperature, was 600 MPa, and dropped to 260 MPa at 1,300 C in air. Although the room-temperature failure was brittle, the high-temperature load-displacement curve shows significant plastic behavior. The oxidation is parabolic and at 1,000 and 1,400 C the parabolic rate constants were, respectively, 2 {times} 10{sup {minus}8} and 2 {times} 10{sup {minus}5} kg{sup 2}{center_dot}m{sup {minus}4}{center_dot}s{sup {minus}1}. The activation energy for oxidation is thus {approx}300 kJ/mol. The room-temperature electrical conductivity is 4.5 {times} 10{sup 6} {Omega}{sup {minus}1}{center_dot}m{sup {minus}1}, roughly twice that of pure Ti. The thermal expansion coefficient in the temperature range 25 to 1,000 C, the room-temperature thermal conductivity, and the heat capacity are respectively, 10 {times} 10{sup {minus}6} C{sup {minus}1}, 43 W/(m{center_dot}K), and 588 J/(kg{center_dot}K). With a hardness of 4 GPa and a Young`s modulus of 320 GPa, it is relatively soft, but reasonably stiff. Furthermore, Ti{sub 3}SiC{sub 2} does not appear to be susceptible to thermal shock; quenching from 1,400 C into water does not affect the postquench bend strength.more » As significantly, this compound is as readily machinable as graphite. Scanning electron microscopy of polished and fractured surfaces leaves little doubt as to its layered nature.« less
Customer Risk from Real-Time Retail Electricity Pricing: Bill Volatility and Hedgability

One of the most critical concerns that customers have voiced in the debate over real-time retail electricity pricing is that they would be exposed to risk from fluctuations in their electricity cost. The concern seems to be that a customer could find itself consuming a large quantity of power on the day that prices skyrocket and thus receive a monthly bill far larger than it had budgeted for. I analyze the magnitude of this risk, using demand data from 1142 large industrial customers, and then ask how much of this risk can be eliminated through various straightforward financial instruments. I find that very simple hedging strategies can eliminate more than 80% of the bill volatility that would otherwise occur. Far from being complex, mystifying financial instruments that only a Wall Street analyst could love, these are simple forward power purchase contracts, and are already offered to retail customers by a number of fully-regulated utilities that operate real-time pricing programs. I then show that a slightly more sophisticated application of these forward power purchases can significantly enhance their effect on reducing bill volatility.
Employment generation in rural Africa : mid-term results from an experimental evaluation of the Youth Opportunities Program in Northern Uganda

This brief summarizes the results of a gender impact evaluation study, entitled Employment generation in rural Africa : mid-term results from an experimental evaluation of the youth opportunities program in Northern Uganda, conducted in the year 2008, in Uganda. The study observed that mid-term results after two years suggest four main findings. First, despite a lack of central monitoring and accountability, most youth invest the transfer in vocational skills and tools. Second, the economic impacts of the transfer are large. Third, the evidence suggests that poor access to credit is a major reason youth cannot start these vocations in the absence of aid. Finally, these economic gains result in modest improvements in social stability. The outcomes are split into three themes: Economic, Alienation, and Subjective Well-being. For each theme, the results are summed and presented as a z-score. The economic impacts are large with an increase in .28 standard deviations. The male and female economic impacts are similar. Funding for the study derives from Gender Action Plan, Uganda Social Action Fund, Spanish Impact Evaluation Fund.
A new indirect adaptive control scheme for time-varying plants

Structures are developed for the control and estimation parts of the indirect adaptive scheme which are more appropriate for time-varying plants. In contrast to the usual pointwise schemes, the new controller structure can meet the control objective exactly for a wide class of plants with smooth but otherwise unrestricted parameter variations. On the other hand, the possibly available knowledge of the form or frequency of variation of the fast parameters is included in the new estimator structure so that, for successful estimation, the overall plant is not restricted to varying slowly with time. The new estimator and control law are combined using the certainty equivalence principle to develop an indirect adaptive control scheme meeting the control objective for plants with time-varying parameters whose fast varying parts are of known form and unknown parts are slow in the mean. >
Shannon Meets Nash on the Interference Channel

The interference channel is the simplest communication scenario where multiple autonomous users compete for shared resources. We combine game theory and information theory to define the notion of a Nash equilibrium region of the interference channel. The notion is game theoretic: it captures the selfish behavior of each user as they compete. The notion is also information theoretic: it allows each user to use arbitrary communication strategies as it optimizes its own performance. We give an exact characterization of the Nash equilibrium region of the two-user linear deterministic interference channel and an approximate characterization of the Nash equilibrium region of the two-user Gaussian interference channel to within 1 bit/s/Hz.