cssi/SciSciGPT-SciSciNet huggingface dataset:
Enabling secure on-line DNS dynamic update

Domain Name System (DNS) is the system for the mapping between easily memorizable host names and their IP addresses. Due to its criticality, security extensions to DNS have been proposed in an Internet Engineering Task Force (IETF) working group to provide authentication. We point out two difficulties in the current DNSSEC (DNS Security Extension) standards in the handling of DNS dynamic updates: the online storage of a zone security key, creating a single point of attack for both inside and outside attackers; and the violation of the role separation principle, which in the context of DNSSEC separates the roles of zone security managers from DNS server administrators. To address these issues, we propose a secure DNS architecture that is based on threshold cryptography. We show that the architecture adheres to the role separation principle without presenting any single point of attack. Our experimental results reveal that, in terms of signature computation times, our architecture incurs negligible performance penalty when using RSA/MD5 signatures but significant overhead when using DSA signatures. It is our belief that the high level of security that can be achieved by the proposed architecture far outweighs its potential overhead, especially in critical DNS zones, such as the .com zone.
The facets of exploitation

This paper proposes four concepts of exploitation that encapsulate common uses of the word in social interactions: unfair advantage, unequal exchange, using persons as means, free-riding. It briefly discusses how these concepts appear in the literature (the first two are prominent in Roemer's classical work), and then examines how these forms of exploitation are related and how they can occur.
Issues related to 1-10-MHz transformer design

Issues related to the design of high-frequency transformers are discussed. An analysis of skin and proximity effects in the conductors and measurements of permeability and hysteresis loss in the magnetic material are combined in a computer-assisted study of the relationships between size, efficiency, and frequency. Experimental data are presented for a prototype transformer. >
Advanced Light Source storage ring RF system

The ALS (Advanced Light Source) RF system splits 300 kW of CW 500-MHz power between two single cell cavities. Compared to past practice this power rating is high. The use of only two cavities, however, has some advantages. It simplifies the waveguide feed system and releases room in straight sections for insertion devices; more importantly, it reduces higher-order-mode and beam impedance problems. >
On the ergodicity of partially hyperbolic systems

Pugh and Shub [PS3] have conjectured that essential accessibility implies ergodicity, for a C 2 , partially hyperbolic, volume-preserving diffeomorphism. We prove this conjecture under a mild center bunching assumption, which is satsified by all partially hyperbolic systems with 1-dimensional center bundle. We also obtain ergodicity results for C 1+γ partially hyperbolic systems.
Modeling patient arrivals in community clinics

We develop improved methods for modeling and simulating the streams of patients arriving at a community clinic. In previous practice, random (unscheduled) patient arrivals were often assumed to follow an ordinary Poisson process (so the corresponding patient interarrival times were randomly sampled from an exponential distribution); and for scheduled arrivals, each patient's tardiness (i.e., the deviation from the scheduled appointment time) was often assumed to be randomly sampled from a normal distribution. A thorough analysis of patient arrival times, obtained from detailed workflow observations in nine community clinics, indicates these assumptions are not generally valid, and the tardiness data sets for this study are best modeled by unbounded Johnson distributions. We also propose a nonhomogeneous Poisson process to model the random patient arrivals; we review a nonparametric approach to estimating the associated mean-value function; and we describe an algorithm for generating random patient arrivals from the estimated model. The adequacy of this model of random patient arrivals can be assessed by standard goodness-of-fit tests. These findings are important since testable scheduling optimization strategies must be based upon accurate models for both random and scheduled patient arrivals. The impacts on modeling, as well as implications for practice management, are discussed.
Clean Technological Change in Developing-Country Industrial Clusters: Mexican Leather Tanning

In many cities in developing countries, clusters of small and medium-sized enterprises create severe pollution problems. Because conventional regulatory approaches are typically ineffective in such situations, policy responses have increasingly focused on promoting voluntary clean technological change. Yet the data and analysis needed to guide such efforts are scarce. This article uses original firm-level survey data on a cluster of small and medium-scale leather tanneries in Leon, Guanajuato—Mexico’s leather goods capital—to identify the factors that drive the adoption of two clean tanning technologies. Using a multivariate probit model to estimate a system of seemingly unrelated regressions, we find—in contrast to conventional wisdom—that neither firm size nor regulatory pressure is positively correlated with adoption. Rather, the key driver of adoption is the firm’s human capital, the same factor that often explains conventional productivity-enhancing technological change. We also find that a private-sector trade association is an important source of technical information about clean technologies.
STARSPOTS, SPIN-ORBIT MISALIGNMENT, AND ACTIVE LATITUDES IN THE HAT-P-11 EXOPLANETARY SYSTEM

United States. National Aeronautics and Space Administration (Origins program grant NNX11AG85G)
Development of a superconducting ELF receiving antenna

The development of an extremely low frequency (ELF) submarine receiving antenna that uses a triaxial array of superconducting quantum interference devices (SQUIDs) has addressed the following six problem areas: 1) achievement of a SQUID sensor with a sensitivity of 10^{-14} T-Hz-1/2; 2) acheivement of a SQUID linear dynamic range of 140 dB; 3) achievement of sensor orthogonality of 10^{-4} rad;4) stabilization of receiver platform motion to 10^{3} rad; 5) processing of SQUID outputs in order to remove residual motion noise;6) provision of a suitable cryogenic environment. The required sensitivity, approximate linear dynamic range, and sensor orthogonality were successfully obtained in a prototype point-contract type triaxial SQUID magnetometer. This magnetometer was used to detect the ELF signal broadcast from the U.S. Navy transmitter in Wisconsin, both in the atmosphere above the water surface and at a depth of 100 m below the ocean surface in a stationary configuration. No measurements have been made as yet with the magnetometer in a towed buoy. Achievement of the platform motion requirement was demonstrated by motion spectrum measurements on a hydrodynamically stabilized buoy designed to be towed by a submarine. Motion excursions within the ELF pass band of 30- 130 Hz were found to be about 10^{-4} rad. This amount of motion requires that motion-generated noise be further reduced by more than 80 dB. The required noise rejection can be achieved by adaptive determination of a vector that is approximately equal to the earth's magnetic field vector. When the adaptive vector is evaluated and combined vectorially with the SQUID outputs, a quantity proportional to the ELF signal vector results in which motion noise is suppressed. This adaptive processing has been studied using a computer simulation of the SQUIDs' motion noise derived from towed-buoy motion data. The feasibility of cooling the SQUID sensors with liquid helium was demonstrated by a prototype long-hold-time dewar of a size capable of fitting a towed communications buoy. The dewar successfully maintained the temperature of a volume sufficiently large to hold a triaxial SQUID sensor package at the temperature of boiling liquid helium for a duration of 102 days.
Control and adaptation of TDMA in wireless networks

Time-division multiple-access (TDMA) is a widely used technique for simultaneous utilization of a single channel by multiple users. In its traditional form, TDMA suffers from a lack of power-efficiency, which is particularly damaging in wireless communications. This paper develops two controlled versions of TDMA, which lead to considerable power-efficiency improvements without a loss in average throughput for all users. The first one provides at least 11 dB improvement in comparison with the traditional TDMA but lacks location-fairness. The second, which is an adaptive version of the first, provides at least 5 dB improvement along with an excellent location-fairness.
A model to evaluate vehicle emission incentive policies in Japan

Using 3 years of data from the 47 prefectures of Japan, we estimate the behavior of households that simultaneously make discrete decisions about vehicle ownership and continuous decisions about driving distance. We use the estimated parameters to calculate elasticities and to simulate the effects of alternative pollu- tion control policies such as taxes on gasoline, distance, or particular cars. Given choices about cars and distance, we also calculate emissions. Since we model simultaneous choices, both the chosen distance and the chosen car can be affected either by a tax on distance or by a tax on car characteristics. We find expected signs for coefficients on price and income. Car choices are relatively inelastic, however, either to taxes on cars or to taxes on gas or distance. Thus, emissions are more affected by taxes on gasoline than by taxes on particular vehicles. Yet, taxes on cars have lower costs on consumers and thus lower marginal cost of abatement. Given that the existing gas tax already achieves some abatement, mostly through driving reduction, this analysis suggests that further abatement from the use of distance- reducing taxes is more costly than achieving some marginal abatement from induced changes in car choices. The option with the lowest cost is to tax each car at a rate proportional to its emission rate.
Measurement of Spin-orbit Misalignment and Nodal Precession for the Planet around Pre-main-sequence Star PTFO 8-8695 from Gravity Darkening

PTFO 8-8695b represents the first transiting exoplanet candidate orbiting a pre-main-sequence star (van Eyken et al. 2012, ApJ, 755, 42). We find that the unusual lightcurve shapes of PTFO 8-8695 can be explained by transits of a planet across an oblate, gravity-darkened stellar disk. We develop a theoretical framework for understanding precession of a planetary orbit's ascending node for the case when the stellar rotational angular momentum and the planetary orbital angular momentum are comparable in magnitude. We then implement those ideas to simultaneously and self-consistently fit two separate lightcurves observed in 2009 December and 2010 December. Our two self-consistent fits yield Mp = 3.0 M_Jup and Mp = 3.6 M_Jup for assumed stellar masses of M* = 0.34 M_☉ and M* = 0.44 M_☉ respectively. The two fits have precession periods of 293 days and 581 days. These mass determinations (consistent with previous upper limits) along with the strength of the gravity-darkened precessing model together validate PTFO 8-8695b as just the second hot Jupiter known to orbit an M-dwarf. Our fits show a high degree of spin-orbit misalignment in the PTFO 8-8695 system: 69° ± 2° or 73°.1 ± 0°.5, in the two cases. The large misalignment is consistent with the hypothesis that planets become hot Jupiters with random orbital plane alignments early in a system's lifetime. We predict that as a result of the highly misaligned, precessing system, the transits should disappear for months at a time over the course of the system's precession period. The precessing, gravity-darkened model also predicts other observable effects: changing orbit inclination that could be detected by radial velocity observations, changing stellar inclination that would manifest as varying vsin i, changing projected spin-orbit alignment that could be seen by the Rossiter–McLaughlin effect, changing transit shapes over the course of the precession, and differing lightcurves as a function of wavelength. Our measured planet radii of 1.64 R_Jup and 1.68 R_Jup in each case are consistent with a young, hydrogen-dominated planet that results from a "hot-start" formation mechanism.
Malawi’s Infrastructure : A Continental Perspective

Infrastructure contributed 1.2 percentage points to the annual per capita growth of Malawi's gross domestic product (GDP) over the past decade, thanks mainly to the revolution in information and communication technology (ICT). Raising the country's infrastructure endowment to that of the region's middle-income countries could further boost annual growth by 3.5 percentage points per capita. Today, Malawi's basic infrastructure indicators look relatively good when compared with other low-income countries in Africa, although the performance of that infrastructure could be significantly improved. Malawi is one of the few African countries to have already reached the Millennium Development Goals (MDGs) for water, almost a decade ahead of the target. The private sector has made Global Management System (GSM) telephone signals widely available without public subsidy. A substantial road investment program has raised the average condition of the country's road network, and a foundation for institutional reform has been laid in the ICT, power, and road transport sectors. Even if those inefficiencies could be eliminated, Malawi will still face an infrastructure funding gap of almost $300 million a year. This could be lessened to $100 million by engaging in regional trade of electricity, using lower-cost supply modalities in water supply and sanitation, and adopting appropriate technologies for road sector development. As long as efficiency gains are captured and spending sustained at the levels of the recent past, the country's infrastructure targets could be reached within 16 years.
Moments of the estimated Sharpe ratio when the observations are not IID

We develop the analytical second-order bias and variance of the estimated Sharpe ratio when the return series is not IID. We show that the bias and variance formulae depend upon the covariance structure of the data generating process.
DAHA-Jones polynomials of torus knots

DAHA-Jones polynomials of torus knots T(r, s) are studied systematically for reduced root systems and in the case of $$C^\vee C_1$$ . We prove the polynomiality and evaluation conjectures from the author’s previous paper on torus knots and extend the theory by the color exchange and further symmetries. The DAHA-Jones polynomials for $$C^\vee C_1$$ depend on five parameters. Their surprising connection to the DAHA-superpolynomials (type A) for the knots $$T(2p+1,2)$$ is obtained, a remarkable combination of the color exchange conditions and the author’s duality conjecture (justified by Gorsky and Negut). The uncolored DAHA-superpolynomials of torus knots are expected to coincide with the Khovanov–Rozansky stable polynomials and the superpolynomials defined via rational DAHA and/or in terms of certain Hilbert schemes. We end the paper with certain arithmetic counterparts of DAHA-Jones polynomials for the absolute Galois group in the case of $$C^\vee C_1$$ , developing the author’s previous results for $$A_1$$ .
On unbounded operators and applications

Abstract Assume that (1) A u = f is a solvable linear equation in a Hilbert space H , A is a linear, closed, densely defined, unbounded operator in H , which is not boundedly invertible, so problem (1) is ill-posed. It is proved that the closure of the operator ( A ∗ A + α I ) − 1 A ∗ , with the domain D ( A ∗ ) , where α > 0 is a constant, is a linear bounded everywhere defined operator with norm ≤ 1 2 α . This result is applied to the variational problem F ( u ) ≔ ‖ A u − f ‖ 2 + α ‖ u ‖ 2 = min , where f is an arbitrary element of H , not necessarily belonging to the range of A . Variational regularization of problem (1) is constructed, and a discrepancy principle is proved.
Parametric Reduced-Order Models of Battery Pack Vibration Including Structural Variation and Pre-Stress Effects

Abstract The goal of this work is to develop a numerical model for the vibration of hybrid electric vehicle (HEV) battery packs to enable probabilistic forced response simulations for the effects of variations. There are two important types of variations that affect their structural response significantly: the prestress that is applied when joining the cells within a pack; and the small, random structural property discrepancies among the cells of a battery pack. The main contributions of this work are summarized as follows. In order to account for these two important variations, a new parametric reduced order model (PROM) formulation is derived by employing three key observations: (1) the stiffness matrix can be parameterized for different levels of prestress, (2) the mode shapes of a battery pack with cell-to-cell variation can be represented as a linear combination of the mode shapes of the nominal system, and (3) the frame holding each cell has vibratory motion. A numerical example of an academic battery pack with pouch cells is presented to demonstrate that the PROM captures the effects of both prestress and structural variation on battery packs. The PROM is validated numerically by comparing full-order finite element models (FEMs) of the same systems.
The demand for ethanol as a gasoline substitute

Abstract This paper estimates household preferences for ethanol (E85) as a gasoline (E10) substitute. I develop a theoretical model linking the shape of the ethanol demand curve to the underlying distribution among households of willingness to pay for ethanol. I estimate the model using instrumental variables techniques and data from many retail fueling stations. I find that a $0.10-per-gallon increase in ethanol's price relative to gasoline leads to a 12–16% decrease in the quantity of ethanol demanded. My findings imply that preferences for ethanol are heterogeneous and that a substantial fraction of households are willing to pay a premium for the fuel. This reduces substantially the simulated efficiency cost of an ethanol content standard, since some households choose ethanol without large subsidies, mitigating deadweight losses.
Utilization of obstetrical ultrasound in a referral population.

Objective. To determine the number of ultrasounds performed prior to presentation to a maternal-fetal medicine (MFM) sub-specialist and the patient's perceived reason for referral.Study design. Women presenting for their first targeted ultrasound at an MFM unit in an urban center between November 2003 and April 2004 reported the number, location, and gestational age (GA) of prior ultrasounds and whether their insurance company had been billed for these studies. They also reported their current GA, insurance type, and perceived reason for referral. Pearson correlation and Kruskal–Wallis were used where appropriate; p < 0.05 was considered significant.Results. Six hundred fifty-five women were invited to participate; 207 declined, leaving 448 available for the final analysis. The median number of prior ultrasounds was two (range 0–11). Twelve percent reported no prior ultrasound, 30% reported having had one, 28% reported having had two, and 29% reported having had three or more. Women presented at a mean GA...
Remote computing--an experimental system: part 1: external specifications

Remote computing has been around as long as computers themselves. More recently, interest has revived in providing remote users with convenient, economical access to a large central computer. Considerable attention has been addressed to its economics and practicality. Several batch-oriented systems have been implemented. The techniques of time-sharing a large or small system have been described, as have the attendant advantages of man-machine interaction for symbolic mathematics and program testing. Several input-output devices have been considered, including typewriters, displays, and dial-voice equipment.
Titan's surface and rotation: new results from Voyager 1 images

Abstract We present an analysis of images of Saturn's moon Titan, obtained by the Voyager 1 spacecraft on November 8–12, 1980. Orange filter (590–640 nm) images were photometrically corrected and a longitudinal average removed from them, leaving residual images with up to 5% contrast, and dominated by surface reflectivity. The resultant map shows the same regions observed at 673 nm by the Hubble Space Telescope (HST). Many of the same albedo features are present in both datasets, despite the short wavelength (600 nm) of the Voyager 1 images. A very small apparent longitudinal offset over the 14 year observation interval places tight constraints on Titan's rotation, which appears essentially synchronous at 15.9458±0.0016 days (orbital period =15.945421±0.000005 days). The detectability of the surface at such short wavelengths puts constraints on the optical depth, which may be overestimated by some fractal models.
Complexes of earth-abundant metals for catalytic electrochemical hydrogen generation under aqueous conditions

Growing global energy demands and climate change motivate the development of new renewable energy technologies. In this context, water splitting using sustainable energy sources has emerged as an attractive process for carbon-neutral fuel cycles. A key scientific challenge to achieving this overall goal is the invention of new catalysts for the reductive and oxidative conversions of water to hydrogen and oxygen, respectively. This review article will highlight progress in molecular electrochemical approaches for catalytic reduction of protons to hydrogen, focusing on complexes of earth-abundant metals that can function in pure aqueous or mixed aqueous–organic media. The use of water as a reaction medium has dual benefits of maintaining high substrate concentration as well as minimizing the environmental impact from organic additives and by-products.
Proton transfers in aromatic systems: How aromatic is the transition state?*

The question as to what extent aromaticity in a reactant or product is expressed in the transition state of a reaction has only recently received serious attention. Inasmuch as aro- maticity is related to resonance, one might expect that, in a reaction that leads to aromatic products, its development at the transition state should lag behind bond changes as is invari- ably the case for the development of resonance in reactions that lead to delocalized products. However, recent experimental and computational studies on proton transfers from carbon acids suggest the opposite behavior, i.e., the development of aromaticity at the transition state is more advanced than the proton transfer. The evidence for this claim is based on the deter- mination of intrinsic barriers that show a decrease with increasing aromaticity. According to the Principle of Nonperfect Synchronization (PNS), this decrease in the intrinsic barrier im- plies a disproportionately large amount of aromatic stabilization of the transition state. Additional evidence for the high degree of transition state aromaticity comes from the cal- culation of aromaticity indices such as HOMA, NICS, and the Bird Index. Possible reasons why the degree to which aromaticity and resonance are expressed at the transition state is dif- ferent are discussed.
Dance posture recognition using wide-baseline orthogonal stereo cameras

In this paper, a robust 3D dance posture recognition system using two cameras is proposed. A pair of wide-baseline video cameras with approximately orthogonal looking directions is used to reduce pose recognition ambiguities. Silhouettes extracted from these two views are represented using Gaussian mixture models (GMM) and used as features for recognition. Relevance vector machine (RVM) is deployed for robust pose recognition. The proposed system is trained using synthesized silhouettes created using animation software and motion capture data. The experimental results on synthetic and real images illustrate that the proposed approach can recognize 3D postures effectively. In addition, the system is easy to set up without any need of precise camera calibration.
On the feasibility of phosphide generation from phosphate reduction: The case of Rh, Ir, and Ag

The feasibility of reductive hydrogen annealing of metal phosphates as a pathway to phosphides has been explored for Rh, Ir and Ag. Phosphate precursors were prepared by combination of metal salts with ammonium monohydrogen phosphate in water. Rh and Ir precursors were isolated by solvent evaporation, whereas the reaction with silver acetate yielded Ag3(PO4) as a precipitate. Thermogravimetric analysis was employed using 5% H2 in Ar to ascertain appropriate reduction conditions for phosphide formation. Rh2P was formed as the sole crystalline phase from slow heating to 375 ◦ C, although energy dispersive spectroscopy suggests amorphous phosphorus may be present as an impurity. Ir2P is best prepared from ramping to 600 ◦ C in an inert atmosphere, followed by hydrogen annealing. Iridium metal is also present as an impurity, apparently arising from the iridium reagent or in the process of preparing the phosphate precursor. Ag3(PO4) does not yield a phosphide upon treatment with hydrogen, instead reducing directly to the metal at temperatures as low as 140 ◦ C.
Torsion in the matching complex and chessboard complex

Abstract Topological properties of the matching complex were first studied by Bouc in connection with Quillen complexes, and topological properties of the chessboard complex were first studied by Garst in connection with Tits coset complexes. Bjorner, Lovasz, Vrecica and Živaljevic established bounds on the connectivity of these complexes and conjectured that these bounds are sharp. In this paper we show that the conjecture is true by establishing the nonvanishing of integral homology in the degrees given by these bounds. Moreover, we show that for sufficiently large n, the bottom nonvanishing homology of the matching complex M n is an elementary 3-group, improving a result of Bouc, and that the bottom nonvanishing homology of the chessboard complex M n , n is a 3-group of exponent at most 9. When n ≡ 2 mod 3 , the bottom nonvanishing homology of M n , n is shown to be Z 3 . Our proofs rely on computer calculations, long exact sequences, representation theory, and tableau combinatorics.
The curious events leading to the theory of shock waves

We review the history of the development of the modern theory of shock waves. Several attempts at an early-theory quickly collapsed for lack of foundations in mathematics and thermodynamics. It is not until the works of Rankine and later Hugoniot that a full theory is established. Rankine is the first to show that within the shock a non-adiabatic process must occur. Hugoniot showed that in the absence of viscosity and heat conduction conservation of energy implies conservation of entropy in smooth regions and a jump in entropy across a shock. Even after the theory is fully developed, old notions continue to pervade the literature well into the early part of the twentieth century.
The Moral Challenge of Ebola

The author reflects on the moral challenge of the Ebola virus and its management. He suggests that the Ebola virus poses a moral challenge to individuals and societies and that moral considerations should play a role in the decision making process which is used to bring the Ebola virus under control. He argues that the only effective and humane strategy to use when attempting to manage the Ebola virus is to attack the disease where it arises.
A Thom isomorphism for infinite rank Euclidean bundles

An equivariant Thom isomorphism theorem in operator Ktheory is formulated and proven for infinite rank Euclidean vector bundles over finite dimensional Riemannian manifolds. The main ingredient in the argument is the construction of a non-commutative C ? -algebra associated to a bundle E ! M, equipped with a compatible connection r, which plays the role of the algebra of functions on the infinite dimensional total space E. If the base M is a point, we obtain the Bott periodicity isomorphism theorem of Higson-Kasparov-Trout [19] for infinite dimensional Euclidean spaces. The construction applied to an even finite rank spin c -bundle over an even-dimensional proper spin c -manifold reduces to the classical Thom isomorphism in topological K-theory. The techniques involve noncommutative geometric functional analysis.
Asymmetric synthesis of α-amino acids via chiral N-alkylidenesulfinamides

Abstract (SR)-(−)-N-[1-(Triethoxymethyl)ethylidene]-p-toluenesulfinamide (2) was synthesized from the addition reaction of triethoxyacetonitrile with MeLi followed by (+)-(R)-d-menthyl p-toluenesulfinate (1R). Sulfinimine 2 underwent complete stereoselective reduction with 9-BBN and addition reaction with allylmagnesium bromide. Optically pure α-amino acids were synthesized from these adducts by simple hydrolysis.
Integral representation of continuous comonotonically additive functionals

In this paper, I first prove an integral representation theorem: Every quasi-integralon a Stone lattice can be represented by a unique upper-continuous capacity. I then apply this representation theorem to study the topological structure of the space of all upper-continuous capacities on a compact space, and to prove the existence of an upper-continuous capacity on the product space of infinitely many compact Hausdorff spaces with a collection of consistent finite marginals.
Monte Carlo Simulations of Spin-Diffusion in a 2-D Heisenberg Paramagnet

We study spin diffusion and spin waves in paramagnetic quantum crystals (solid 3He, for example) by direct simulation of a square lattice of atoms interacting via a nearest-neighbor Heisenberg exchange Hamiltonian. Recently, Cowan and Mullin have used a moments method to study spin transport at arbitrary polarizations. We test their analytic results by calculating the statistical spin correlation function from molecular dynamics simulations using a Monte Carlo algorithm to average over initial spin configurations. Since it is not practical to diagonalize the S\({\raise0.7ex\hbox{$1$} \!\mathord{\left/ {\vphantom {1 2}}\right.\kern-\nulldelimiterspace}\!\lower0.7ex\hbox{$2$}}\) exchange Hamiltonian for a lattice which is of sufficient size to study long-wavelength (hydrodynamic) fluctuations, we instead study the S→∞ limit and treat each spin as a vector with a classical equation of motion. We compare our simulations with the assumptions of the moments method regarding the short-time behavior and the long exponential tail of the correlation function. We also present our numerical results for the polarization dependence of the longitudinal spin diffusion coefficient and the complex transverse spin diffusion coefficient.
Disturbing implications of a cosmological constant

In this paper we consider the implications of a cosmological constant for the evolution of the universe, under a set of assumptions motivated by the holographic and horizon complementarity principles. We discuss the ``causal patch'' description of spacetime required by this framework, and present some simple examples of cosmologies described this way. We argue that these assumptions inevitably lead to very deep paradoxes, which seem to require major revisions of our usual assumptions.
Genetic noise control via protein oligomerization

Gene expression in a cell entails random reaction events occurring over disparate time scales. Thus, molecular noise that often results in phenotypic and population-dynamic consequences sets a fundamental limit to biochemical signaling. While there have been numerous studies correlating the architecture of cellular reaction networks with noise tolerance, only a limited effort has been made to understand the dynamic role of protein-protein interactions. We have developed a fully stochastic model for the positive feedback control of a single gene, as well as a pair of genes (toggle switch), integrating quantitative results from previous in vivo and in vitro studies. In particular, we explicitly account for the fast binding-unbinding kinetics among proteins, RNA polymerases, and the promoter/operator sequences of DNA. We find that the overall noise-level is reduced and the frequency content of the noise is dramatically shifted to the physiologically irrelevant high-frequency regime in the presence of protein dimerization. This is independent of the choice of monomer or dimer as transcription factor and persists throughout the multiple model topologies considered. For the toggle switch, we additionally find that the presence of a protein dimer, either homodimer or heterodimer, may significantly reduce its random switching rate. Hence, the dimer promotes the robust function of bistable switches by preventing the uninduced (induced) state from randomly being induced (uninduced). The specific binding between regulatory proteins provides a buffer that may prevent the propagation of fluctuations in genetic activity. The capacity of the buffer is a non-monotonic function of association-dissociation rates. Since the protein oligomerization per se does not require extra protein components to be expressed, it provides a basis for the rapid control of intrinsic or extrinsic noise. The stabilization of regulatory circuits and epigenetic memory in general is of direct implications to organism fitness. Our results also suggest possible avenues for the design of synthetic gene circuits with tunable robustness for a wide range of engineering purposes.
MATHLAB: a program for on-line machine assistance in symbolic computations

A mathematical scientist experiments. Today, his test tube and his breadboard are blackboard and paper. He may, it is true, have available a computer, but its role is numerical and its results are delivered not today, not tomorrow, but the day after the final programming bug is corrected. The computer is not present during the most creative phases of the scientist's labor. The purpose of MATHLAB is to provide the scientist with computational aid of a much more intimate and liberating nature.
Emergency Response, Doctrinal Confusion, and Federalism in the Deepwater Horizon Oil Spill

The Deepwater Horizon oil spill was accompanied by intergovernmental blame casting and criticisms similar to that of Hurricane Katrina. The federal response was often viewed as slow, state officials were unsure of their role, and local officials complained that they were not adequately consulted. However, natural and oil pollution disasters have relief and regulatory regimes based on doctrines different from those governing natural disasters. This article discusses those doctrines one of which is characterized by “shared power”; the other reflects greater federal direction. The balance of national and state powers inherent in federalism can also lead to confusion and delay in disaster response, particularly when there are overlapping laws and programs and unrealistic state and local expectations.
Maximum Fuel Economy-Oriented Power Management Design for a Fuel Cell Vehicle Using Battery and Ultracapacitor

A single energy storage element (ESE) has been used in fuel cell (FC) vehicles to improve the FC dynamic response and to recover the braking energy. An energy storage system (ESS) consisting of hybrid ESEs extends the capabilities of single ESE and is, therefore, capable of achieving an optimized performance with improved life cycles for ESS. In this paper, an FC vehicle power train configuration is presented, where a three-port isolated triple-half-bridge dc/dc converter is applied to interface a power dense ultracapacitor (UC) and an energy dense battery unit (BU). A design routine is provided to size the BU and UC to achieve the lightest mass at a 95 % efficiency. Furthermore, a control strategy is developed to achieve the maximum fuel economy of the FC. The state of charge of the BU and UC is also controlled in a dynamic environment and maintained after the driving cycle. Two different approaches of the proposed control strategy have been implemented. The system loss of each method has been compared. The simulation and experimental results based on simplified urban driving cycles are presented to validate the proposed maximum fuel economy design.
Chemo- and diastereoselective tandem dual oxidation of B(pin)-substituted allylic alcohols: synthesis of B(pin)-substituted epoxy alcohols, 2-keto-anti-1,3-diols and dihydroxy-tetrahydrofuran-3-ones

A novel retrosynthetic disconnection for the stereoselective preparation of α,α′-dioxygenated carbonyl compounds is disclosed. Herein we report a method to divert the oxidation of vinyl boronate esters from the B–C bond to the CC bond, resulting in a new stereoselective class of oxidation products from vinyl boronate esters. Treatment of 2-B(pin)-substituted allylic alcohols with catalytic OV(acac)2 and TBHP resulted in a highly chemo- and diastereoselective directed epoxidation to provide B(pin)-substituted epoxy alcohols (55–96% yield, dr > 20 : 1). In the case of B(pin)-substituted bis-allylic alcohols, highly substituted bis-epoxy alcohols with five contiguous stereocenters were obtained (dr > 20 : 1). Furthermore, the difference in reactivity between allylic alcohols and 2-B(pin)-substituted allylic alcohols towards epoxidation enabled the selective oxidation of the allylic alcohol in the presence of TBHP and VO(acac)2. The reactivity difference between the two allylic alcohols suggests CCB(pin) to be more electron deficient than CC(alkyl). The B(pin)-substituted epoxy alcohols are also useful synthetic intermediates. Tandem vanadium catalyzed epoxidation of the 2-B(pin)-substituted allylic and bis-allylic alcohols with excess TBHP generated the intermediate epoxides and bis-epoxides, respectively. Subsequent addition of NaOH resulted in the oxidation of the B–C bond of the B(pin)-substituted epoxides to afford 2-keto-anti-1,3-diols (60–83% yield) and epoxide-substituted 2-keto-anti-1,3-diols (60–78% yield, dr > 20 : 1). The latter underwent a novel facile acid-mediated cyclization to furnish fully substituted dihydroxy-tetrahydrofuran-3-ones (65–91% yield, dr > 20 : 1). Such compounds are difficult to efficiently access via conventional synthetic methods.
C–N Coupling of 1,2‐Dihydro‐2,2,4‐trimethylquinoline Derivatives via a Silver(I)‐Catalyzed Direct Functionalization of a C–H Bond

Two C,N-linked dimeric 1,2-dihydro-2,2,4-trimethylquinolines, namely 6-chloro-1-(6-chloro-1,2-dihydro-2,2,4-trimethylquinolin-8-yl)-1,2-dihydro-2,2,4-trimethylquinoline (3a) and 6-ethoxy-1-(6-ethoxy-1,2-dihydro-2,2,4-trimethylquinolin-8-yl)-1,2-dihydro-2,2,4-trimethylquinoline (3b), have been prepared through a silver-catalyzed dimerization of their corresponding monomers. The effect of different silver salts on the reaction was also investigated, and the obtained results suggest that silver ions effectively catalyzed the formation of a C–N bond under these mild conditions. This represents one of the rare reports on the silver-catalyzed C–N bond formation through a coupling of a secondary amine and an activated aromatic system, via a direct C–H functionalization. Theoretical studies showed that these dimeric structures favor a conformation in which their monomer units are oriented approximately perpendicular to each other, with an intramolecular hydrogen bond (N–H distance of 2.33 A) forming between the hydrogen atom of the amine in one of the monomeric units and the tertiary nitrogen atom of the other one.
The effects of a remote stereogenic center in the Lewis base catalyzed aldol additions of chiral trichlorosilyl enolates.

Chiral trichlorosilyl enolates bearing a remote stereogenic center were employed in the phosphoramide-catalyzed aldol reaction. The additions of the methyl ketone enolates proceeded with only moderate diastereoselectivities. The addition of the Z-enolate to various aldehydes selectively produced the syn relative diastereomers. In both cases, the effect of the β-silyloxy stereogenic center was modest, and the internal diastereoselection was mainly controlled by the catalyst.
Collaborative data gathering in wireless sensor networks using measurement co-occurrence

Wireless ad hoc networks of battery-powered microsensors (WSNs) are proliferating rapidly and transforming how information is gathered and processed, and how we affect our environment. The limited energy of those sensors poses the challenge of using such systems in an energy efficient manner to perform various activities. A common activity of many applications of WSNs is that of data gathering: for each time step, gather the measurement from each sensor to a base station. Often there is redundancy and/or dependency among the sensor measurements. How to identify the data redundancy/dependency and utilize them on improving energy efficiency of data gathering has been one of the attractive topics. We propose using measurement co-occurrence to identify data redundancy and a novel collaborative data gathering approach utilizing co-occurrence that offers a trade-off between the communication cost of data gathering versus errors at estimating the sensor measurements at the base station. A key tenant of our approach is to have sensors with co-occurring measurements alternate in transmitting such co-occurring measurements to the base station, and having the base station make inferences about the sensor measurements utilizing only the data transmitted to it. We present two effective in-network methods for detecting co-occurrence of measurements, as well as a simple and efficient protocol for scheduling the transmission of the sensor measurements to the base station. We provide experimental results on synthetic and real datasets showing that the proposed system offers substantial (up to 65%) reduction of the communication costs of data gathering with a small number of measurement inference errors (<6%) at the base station.
The thermal rearrangements of halocyclopropenes

Abstract The gas phase thermal chemistry of several halocyclopropenes has been investigated. In each instance the cyclopropene was converted cleanly to an allene. The gas phase thermolysis of halocyclopropenes leads to allenes.
On volumes of hyperbolic Coxeter polytopes and quadratic forms

In this paper, we compute the covolume of the group of units of the quadratic form \({f_d^n(x) = x_1^2+x_2^2+ \cdots +x_n^2-dx_{n+1}^2}\) with d an odd, square-free, positive integer. Mcleod has determined the hyperbolic Coxeter fundamental domain of the reflection subgroup of the group of units of the quadratic form \({f_3^n}\). We apply our covolume formula to compute the volumes of these hyperbolic Coxeter polytopes.
DO GOVERNMENT POLICIES THAT PROMOTE COMPETITION ENCOURAGE—OR DISCOURAGE—NEW PRODUCT AND PROCESS DEVELOPMENT IN LOW AND MIDDLE INCOME COUNTRIES?

Previous work has shown that firms in low and middle-income countries in Eastern Europe and Central Asia that feel greater pressure to innovate from their competitors are more likely to introduce new products and services than firms that do not feel pressure (Carlin and others 2001; World Bank 2004). However, competition also appears to affect innovation in other ways. In particular, firms in these countries that face greater price competition appear to be less likely to innovate than other firms (Carlin and others 2001). The author assesses how competition and trade policy affect these different aspects of competition and, consequently, assesses their net impact on innovation. He finds that reducing tariffs and enacting and enforcing competition laws modestly increases both the pressure that firms feel regarding innovation and the level of price competition in the domestic economy. The net impact that lower tariffs have on new product and process development appears to be negative but small-for the most part the opposing effects cancel out. In contrast, stricter competition laws and better enforcement of those laws appear to increase the likelihood of new product and process development, especially when competition is treated as endogenous to innovation.
When Governments Regulate Governments

This article advances a political theory of regulation that accounts for the choices of regulators and regulated entities when both are governments. Leading theories of regulation assume that governments regulate profit-maximizing firms: Governments set rules, to which firms respond rationally in ways that constrain their behavior. But often the entities that governments regulate are other governments. We argue that government agencies and private firms often face different compliance costs, and that agencies have greater incentives than firms to appeal regulations through political channels. Simultaneously, the typical enforcement instruments that regulators use to influence firm behavior may be less effective against governments. Our empirical subjects are public and private entities’ compliance with the U.S. Clean Air Act and Safe Drinking Water Act. We find that, compared with private firms, governments violate these laws significantly more frequently and are less likely to be penalized for violations.
Planning with preferences using logic programming

We present a declarative language, ${\cal PP}$, for the high-level specification of preferences between possible solutions (or trajectories) of a planning problem. This novel language allows users to elegantly express non-trivial, multi-dimensional preferences and priorities over such preferences. The semantics of ${\cal PP}$ allows the identification of most preferred trajectories for a given goal. We also provide an answer set programming implementation of planning problems with ${\cal PP}$ preferences.
Using systematic reviews and meta-analyses to support regulatory decision making for neurotoxicants: lessons learned from a case study of PCBs

We examined prospective cohort studies evaluating the relation between prenatal and neonatal exposure to polychlorinated biphenyls (PCBs) and neurodevelopment in children to assess the feasibility of conducting a meta-analysis to support decision making. We described studies in terms of exposure and end point categorization, statistical analysis, and reporting of results. We used this evaluation to assess the feasibility of grouping studies into reasonably uniform categories. The most consistently used tests included Brazelton's Neonatal Behavioral Assessment Scale, the neurologic optimality score in the neonatal period, the Bayley Scales of Infant Development at 5-8months of age, and the McCarthy Scales of Children's Abilities in 5-year-olds. Despite administering the same tests at similar ages, the studies were too dissimilar to allow a meaningful quantitative examination of outcomes across cohorts. These analyses indicate that our ability to conduct weight-of-evidence assessments of the epidemiologic literature on neurotoxicants may be limited, even in the presence of multiple studies, if the available study methods, data analysis, and reporting lack comparability.
Catalytic, Enantioselective α-Additions of Isocyanides: Lewis Base Catalyzed Passerini-Type Reactions

The generality of catalytic, enantioselective α-additions of isocyanides to aldehydes has been demonstrated (Passerini-type reactions). The catalytic system of silicon tetrachloride and a chiral bisphosphoramide (R,R)-1b provided high yields and good to excellent enantioselectivities for the addition of tert-butyl isocyanide to a wide range of aldehydes (aromatic, heteroaromatic, olefinic, acetylenic, aliphatic). Aqueous workup afforded the α-hydroxy tert-butyl amides whereas a low-temperature methanol quench followed by basic workup afforded the α-hydroxy methyl esters. The reaction is also successful for other isocyanides, albeit with reduced enantioselectivity. Reaction conditions, particularly the rate of addition of the isocyanide was found to be crucial for good yields and high selectivities.