cssi/SciSciGPT-SciSciNet huggingface dataset:
System modeling for the longitudinal beam dynamics control problem in heavy ion induction accelerators

We address the problem of developing system models that are suitable for studying the control of the longitudinal beam dynamics in induction accelerators for heavy ions. In particular, we present the preliminary results of our efforts to devise a general framework for building detailed, integrated models of accelerator systems consisting of pulsed power modulator circuits, induction cells, beam dynamics, and control system elements. Such a framework will permit us to analyze and design the pulsed power modulators and the control systems required to effect precise control over the longitudinal beam dynamics. >
CONSISTENCY UNDER SAMPLING OF EXPONENTIAL RANDOM GRAPH MODELS

The growing availability of network data and of scientific interest in distributed systems has led to the rapid development of statistical models of network structure. Typically, however, these are models for the entire network, while the data consists only of a sampled sub-network. Parameters for the whole network, which is what is of interest, are estimated by applying the model to the sub-network. This assumes that the model is consistent under sampling, or, in terms of the theory of stochastic processes, that it defines a projective family. Focusing on the popular class of exponential random graph models (ERGMs), we show that this apparently trivial condition is in fact violated by many popular and scientifically appealing models, and that satisfying it drastically limits ERGM's expressive power. These results are actually special cases of more general results about exponential families of dependent random variables, which we also prove. Using such results, we offer easily checked conditions for the consistency of maximum likelihood estimation in ERGMs, and discuss some possible constructive responses.
Targeting Incentives to Reduce Habitat Fragmentation

The fragmentation of wildlife habitat has long been recognized as a principal threat to terrestrial biodiversity. In this paper, we develop a theoretical model to analyze the spatial targeting of incentives for the restoration of forested landscapes when land quality is spatially heterogeneous and wildlife habitat can be enhanced by reducing fragmentation. We consider a regulator who uses subsidies to encourage the conversion of private agricultural land to forest on a pre-defined set of landscapes. The regulator can observe land-use choices, but not the opportunity costs on individual land parcels. The important insight to emerge from the theoretical analysis is that solutions at or near corners are a strong possibility—on each landscape, either none or all of the agricultural land should be converted to forest. Corner solutions are directly linked to the spatial process determining habitat benefits. To verify the theoretical insight, we present a simulation of the effects of incentive-based policies on the spatial distribution of forests in South Carolina. The empirical methodology integrates an econometric model of land-use change with GIS-based landscape simulations. The empirical findings strongly support our conjecture regarding corner solutions, and the optimal targeting policy is shown to produce substantial welfare gains over a spatially-uniform incentive.
Detectability of exoplanetary transits from radial velocity surveys

Of the known transiting extrasolar planets, a few have been detected through photometric follow-up observations of radial velocity planets. Perhaps the best known of these is the transiting exoplanet HD 209458b. For hot Jupiters (periods less than ∼5 d), the a priori information that 10 per cent of these planets will transit their parent star due to the geometric transit probability leads to an estimate of the expected transit yields from radial velocity surveys. The radial velocity information can be used to construct an effective photometric follow-up strategy which will provide optimal detection of possible transits. Since the planet-harbouring stars are already known in this case, one is only limited by the photometric precision achievable by the chosen telescope/instrument. The radial velocity modelling code presented here automatically produces a transit ephemeris for each planet data set fitted by the program. Since the transit duration is brief compared with the fitted period, we calculate the maximum window for obtaining photometric transit observations after the radial velocity data have been obtained, generalizing for eccentric orbits. We discuss a typically employed survey strategy which may contribute to a possible radial velocity bias against detection of the very hot Jupiters which have dominated the transit discoveries. Finally, we describe how these methods can be applied to current and future radial velocity surveys.
Some groups with computable Chermak-Delgado lattices

Let $G$ be a finite group and let $H \leq G$. We refer to $\ord {H} \ord {C_G(H)}$ as the {\it Chermak-Delgado measure of $H$} with respect to $G$. Originally described by A. Chermak and A. Delgado, the collection of all subgroups of $G$ with maximal Chermak-Delgado measure, denoted $\CD {G}$, is a sublattice of the lattice of all subgroups of $G$. In this paper we note that if $H \in \CD G$ then $H$ is subnormal in $G$ and prove if $K$ is a second finite group then $\CD {G \times K} = \CD G \times \CD K$. We additionally describe the $\CD {G \wr C_p}$ where $G$ has a non-trivial center and $p$ is an odd prime and determine conditions for a wreath product to be a member of its own Chermak-Delgado lattice. We also examine the behavior of centrally large subgroups, a subset of the Chermak-Delgado lattice. DOI: 10.1017/S0004972712000196
Slow propagation, anomalous absorption, and total external reflection of surface plasmon polaritons in nanolayer systems

We predict that a nanoscopic, high-permittivity layer on the surface of a plasmonic metal can cause total external reflection of surface plasmon polaritons (SPPs). Such a layer can be used as a mirror in nanoplasmonics, in particular for resonators of nanolasers and spasers and also can be used in adiabatic nanooptics. We also show that the earlier predicted slow propagating SPP modes, especially those with negative refraction, are highly damped.
Computational Geometry Column 34

Problems presented at the open-problem session of the 14th Annual ACM Symposium on Computational Geometry are listed.
Genetic diversity in cultured and wild marine cyanomyoviruses reveals phosphorus stress as a strong selective agent

Viruses that infect marine cyanobacteria–cyanophages–often carry genes with orthologs in their cyanobacterial hosts, and the frequency of these genes can vary with habitat. To explore habitat-influenced genomic diversity more deeply, we used the genomes of 28 cultured cyanomyoviruses as references to identify phage genes in three ocean habitats. Only about 6–11% of genes were consistently observed in the wild, revealing high gene-content variability in these populations. Numerous shared phage/host genes differed in relative frequency between environments, including genes related to phosphorous acquisition, photorespiration, photosynthesis and the pentose phosphate pathway, possibly reflecting environmental selection for these genes in cyanomyovirus genomes. The strongest emergent signal was related to phosphorous availability; a higher fraction of genomes from relatively low-phosphorus environments–the Sargasso and Mediterranean Sea–contained host-like phosphorus assimilation genes compared with those from the N. Pacific Gyre. These genes are known to be upregulated when the host is phosphorous starved, a response mediated by pho box motifs in phage genomes that bind a host regulatory protein. Eleven cyanomyoviruses have predicted pho boxes upstream of the phosphate-acquisition genes pstS and phoA; eight of these have a conserved cyanophage-specific gene (PhCOG173) between the pho box and pstS. PhCOG173 is also found upstream of other shared phage/host genes, suggesting a unique regulatory role. Pho boxes are found upstream of high light-inducible (hli) genes in cyanomyoviruses, suggesting that this motif may have a broader role than regulating phosphorous-stress responses in infected hosts or that these hlis are involved in the phosphorous-stress response.
Small-Molecule Allosteric Activators of Sirtuins

The mammalian sirtuins (SIRT1-7) are NAD(+)-dependent lysine deacylases that play central roles in cell survival, inflammation, energy metabolism, and aging. Members of this family of enzymes are considered promising pharmaceutical targets for the treatment of age-related diseases including cancer, type 2 diabetes, inflammatory disorders, and Alzheimer's disease. SIRT1-activating compounds (STACs), which have been identified from a variety of chemical classes, provide health benefits in animal disease models. Recent data point to a common mechanism of allosteric activation by natural and synthetic STACs that involves the binding of STACs to a conserved N-terminal domain in SIRT1. Compared with polyphenols such as resveratrol, the synthetic STACs show greater potency, solubility, and target selectivity. Although considerable progress has been made regarding SIRT1 allosteric activation, key questions remain, including how the molecular contacts facilitate SIRT1 activation, whether other sirtuin family members will be amenable to activation, and whether STACs will ultimately prove safe and efficacious in humans.
Asymmetric total synthesis of (+)- and (-)-clusianone and (+)- and (-)-clusianone methyl enol ether via ACC alkylation and evaluation of their anti-HIV activity.

The total asymmetric synthesis of (+)- and (−)-clusianone and (+)- and (−)-clusianone methyl enol ether is reported. Asymmetric induction is achieved through the use of ACC alkylation, providing the key intermediates with an er of 99:1. The four synthetic compounds were evaluated for their anti-HIV activity. Both (+)- and (−)-clusianone displayed significant anti-HIV activity.
Instantons, concordance, and whitehead doubling

We use moduli spaces of instantons and Chern-Simons invariants of flat connections to prove that the Whitehead doubles of (2;2 n − 1) torus knots are independent in the smooth knot concordance group; that is, they freely generate a subgroup of infinite rank. Call two knots in the 3-sphere concordant if they arise as the boundary of a smooth and properly embedded cylinder in the 3-sphere times an interval. Concordance is clearly an equivalence relation. Modulo this relation, the set of knots forms an abelian group C, with the role of addition played by connected sum and inverse given by considering the mirror image, with reversed orientation. This concordance group is a much studied object, well motivated by its role as a gateway into the mysterious world of 4-dimensional topology. Indeed, even in this relative situation of studying 3-dimensional manifolds in relation to the 4-dimensional manifolds they bound, one can observe the distinction between the smooth and topological categories in dimension four. Moreover, the group structure afforded by passing to concordance paves a clearer path through the often intractable field of knot theory. Our results focus on a particular satellite operation, (positive, untwisted) Whitehead doubling, and its effect on the concordance group, see Figure 1 and Section 3.1 for a definition. Our motivation comes from the following conjecture. To state it recall that a knot is slice if it is concordant to the unknot or, equivalently, if it bounds a smooth and properly embedded disk in the 4-ball.
Different Modes of Retrovirus Restriction by Human APOBEC3A and APOBEC3G In Vivo

The apolipoprotein B editing complex 3 (A3) cytidine deaminases are among the most highly evolutionarily selected retroviral restriction factors, both in terms of gene copy number and sequence diversity. Primate genomes encode seven A3 genes, and while A3F and 3G are widely recognized as important in the restriction of HIV, the role of the other genes, particularly A3A, is not as clear. Indeed, since human cells can express multiple A3 genes, and because of the lack of an experimentally tractable model, it is difficult to dissect the individual contribution of each gene to virus restriction in vivo. To overcome this problem, we generated human A3A and A3G transgenic mice on a mouse A3 knockout background. Using these mice, we demonstrate that both A3A and A3G restrict infection by murine retroviruses but by different mechanisms: A3G was packaged into virions and caused extensive deamination of the retrovirus genomes while A3A was not packaged and instead restricted infection when expressed in target cells. Additionally, we show that a murine leukemia virus engineered to express HIV Vif overcame the A3G-mediated restriction, thereby creating a novel model for studying the interaction between these proteins. We have thus developed an in vivo system for understanding how human A3 proteins use different modes of restriction, as well as a means for testing therapies that disrupt HIV Vif-A3G interactions.
A Comparison of Fundamental Noise in Kinetic Inductance Detectors and Transition Edge Sensors for Millimeter-Wave Applications

Kinetic inductance detectors (KIDs) show promise as a competitive technology for astronomical observations over a wide range of wavelengths. We are interested in comparing the fundamental limitations to the sensitivity of KIDs with that of transition edge sensors (TESs) at millimeter wavelengths, specifically over the wavelengths required for studies of the Cosmic Microwave Background (CMB). We calculate the total fundamental noise arising from optical and thermal excitations in TESs and KIDs for a variety of bath temperatures and optical loading scenarios for applications at millimeter wavelengths. Special consideration is given to the case of ground-based observations of 100 GHz radiation with a 100 mK bath temperature, conditions consistent with the planned second module of the QUBIC telescope, a CMB instrument Battistelli (Astropart Phys 34:705, 2011). Under these conditions, a titanium nitride KID with optimized critical temperature pays a few percent noise penalty compared to a typical optimized TES.
Bias of a Value-at-Risk estimator

Abstract We develop the analytical second-order bias of a Value-at-Risk estimator based on an ARCH(1) volatility specification when the parameters are estimated by the method of quasi maximum likelihood. We show that the bias results from two sources: assumption on the distribution of the standardized residuals and the parameter estimation error.
Security Council Resolution 1540 to Combat WMD Terrorism: Effectiveness and Legitimacy in International Legislation

Faced with the urgent and grave threat of WMD terrorism, the international community has responded with a new approach of international legislation by adopting Security Council Resolution 1540. The traditional approach of multilateral treaties on WMD has primarily been aimed at the prevention of proliferation of such weapons to states and not to non-state actors. Another traditional approach of utilising anti-terrorism treaties has been a sort of patchwork, and thus provides no guarantee that a new treaty is made in a timely manner in response to a newly emerging type of terrorism. By contrast, the new approach of international legislation through Council resolutions makes it possible to enact rules that legally bind all UN members immediately and automatically without exception and are equivalent to those in a treaty instantly ratified by all UN members. Indeed, a new thinking is necessary to effectively respond to a new, urgent and grave threat to the international community. In that sense, Resolution 1540 is welcome. This does not, however, mean that everything is allowed if it is effective to deal with the present or imminent threat. Not only from the viewpoint of legitimacy, which guarantees the long-standing effectiveness, but also from that of the rule of law in the international community, it seems of fundamental importance to establish some kind of understanding that we discuss in this article, if international legislation by the Security Council is destined to become inevitable in the future and is to be better implemented.
The Distortionary Effects of Government Procurement: Evidence from Medicaid Prescription Drug Purchasing

In 2003 the federal-state Medicaid program provided prescription drug coverage to more than 50 million people. To determine the price that it will pay for each drug, Medicaid uses the average private sector price. When Medicaid is a large part of the demand for a drug, this creates an incentive for its maker to increase prices for other health care consumers. Using drug utilization and expenditure data for the top 200 drugs in 1997 and in 2002, we investigate the relationship between the Medicaid market share (MMS) and the average price of a prescription. Our estimates imply that a 10-percentage-point increase in the MMS is associated with a 7 to 10 percent increase in the average price of a prescription. In addition, the Medicaid rules increase a firm's incentive to introduce new versions of a drug in order to raise price. We find empirical evidence that firms producing newer drugs with larger sales to Medicaid are more likely to introduce new versions. Taken together, our findings suggest that government procurement rules can alter equilibrium price and product proliferation in the private sector.
Venus high temperature atmospheric dropsonde and extreme-environment seismometer (HADES) ☆

Abstract The atmospheric composition and geologic structure of Venus have been identified by the US National Research Council׳s Decadal Survey for Planetary Science as priority targets for scientific exploration; however, the high temperature and pressure at the surface, along with the highly corrosive chemistry of the Venus atmosphere, present significant obstacles to spacecraft design that have severely limited past and proposed landed missions. Following the methodology of the NASA Innovative Advanced Concepts (NIAC) proposal regime and the Collaborative Modeling and Parametric Assessment of Space Systems (COMPASS) design protocol, this paper presents a conceptual study and initial feasibility analysis for a Discovery-class Venus lander capable of an extended-duration mission at ambient temperature and pressure, incorporating emerging technologies within the field of high temperature electronics in combination with novel configurations of proven, high Technology Readiness Level (TRL) systems. Radioisotope Thermal Power (RTG) systems and silicon carbide (SiC) communications and data handling are examined in detail, and various high-temperature instruments are proposed, including a seismometer and an advanced photodiode imager. The study combines this technological analysis with proposals for a descent instrument package and a relay orbiter to demonstrate the viability of an integrated atmospheric and in-situ geologic exploratory mission that differs from previous proposals by greatly reducing the mass, power requirements, and cost, while achieving important scientific goals.
Germanium‐Modified Cordierite Ceramics with Low Thermal Expansion

Magnesium cordierite ceramics modified by ionic substitution of Ge for Si were synthesized, fabricated, and characterized. The effect of the amount of ionic substitution on thermal expansion was investigated. Ionic substitution of ∼20% germanium for silicon reduces thermal expansion to zero at room temperature. A processing schedule to achieve nearly theoretical densities in germanium cordierite specimens was developed, and the microstructures of sintered samples were examined by scanning electron microscopy. Other thermal properties such as specific heat and thermal conductivity were also measured for the germanium-modified cordierites.
Qualitative physics: towards the automation of systems problem solving

Abstract We discuss some of the key concepts and goals in the areas connected with qualitative and common-sense reasoning from the systems and simulation perspective. We critically examine the general research agenda associated with common-sense reasoning about physical systems and find much overlap with existing systems concepts. We suggest that a rapprochement with research in systems modelling could contribute to the progress of both fields. Indeed, both are concerned with enhancing systems problem solving—with the computer in a subsidiary role (systems research) or taking the lead (qualitative reasoning). We discuss some of the apparent misconceptions among artificial intelligence researchers about systems research and offer some suggestions for fruitful collaborations and research directions.
ALEXANDER-LIN TWISTED POLYNOMIALS

Lin's definition of twisted Alexander knot polynomial is extended for finitely presented groups. Cha's fibering obstruction theorem is generalized. The group of the 2-twist-spun trefoil knot is seen to have a faithful representation that yields a trivial twisted Alexander polynomial.
Do Consumers Pay for Being Healthy Conscious?— An Analysis of Price Discrimination on Healthier Food Product

‘Healthier food product’ has experienced a rapid growth rate in recent years in U.S. because of the increasing consumer demand for healthier and environmental friendlier lifestyle. This analysis is looking for price discrimination evidences by comparing price cost margins of regular food products and healthier food products. Price cost margins are computed by solving firms' profit maximization problem and relevant parameters are estimated from consumers' choice decisions. Specifically, price elasticities and price coefficients are estimated using nonlinear GMM estimation in order to construct price cost margin. The empirical analysis employs product level ketchup data across 50 MSA in U.S. from 2001 to 2006.
Hadron physics from the global color model of QCD

Abstract We review recent progress in modeling the quark-gluon content of mesons and their low-energy interactions through the Global Color Model field theory. An emphasis is placed on techniques that are shared with the approach based on truncations of the Dyson-Schwinger equations of QCD. In contrast to most other field theory models for QCD degrees of freedom in hadron physics, this approach directly deals with the derived intrinsic space-time extent of the meson modes in their role as field variables and can accommodate confinement as well as dynamical breaking of chiral symmetry. Various theoretical techniques and approximations found useful in this approach are described. Selected applications reviewed here include the properties and interactions of the Goldstone bosons, interaction vertex functions, low energy chiral observables, electromagnetic interactions and form factors, and transition form factors. Some initial considerations of Vector Meson Dominance and pion loop processes are discussed.
Fractionalization in the Cuprates: Detecting the Topological Order

The precise theoretical characterization of a fractionalized phase in spatial dimensions higher than one is through the concept of ``topological order.'' We describe a physical effect that is a robust and a direct consequence of this hidden order that should enable a precise experimental characterization of fractionalized phases. In particular, we propose specific ``smoking-gun'' experiments to unambiguously settle the issue of electron fractionalization in the underdoped cuprates.
The bipolar spectrum: Conceptions and misconceptions

Objective:This review aims to address concerns about the potential overinclusiveness and vagueness of bipolar spectrum concepts, and also, concerns about the overlap between bipolar illness and bor...
Bayesian inference of galaxy formation from the K‐band luminosity function of galaxies: tensions between theory and observation

We conduct Bayesian model inferences from the observed K-band luminosity function of galaxies in the local Universe, using the semi-analytic model (SAM) of galaxy formation introduced in Lu et al. The prior distributions for the 14 free parameters include a large range of possible models. We find that some of the free parameters, e.g. the characteristic scales for quenching star formation in both high-mass and low-mass haloes, are already tightly constrained by the single data set. The posterior distribution includes the model parameters adopted in other SAMs. By marginalizing over the posterior distribution, we make predictions that include the full inferential uncertainties for the colour–magnitude relation, the Tully–Fisher relation, the conditional stellar mass function of galaxies in haloes of different masses, the H i mass function, the redshift evolution of the stellar mass function of galaxies and the global star formation history. Using posterior predictive checking with the available observational results, we find that the model family (i) predicts a Tully–Fisher relation that is curved; (ii) significantly overpredicts the satellite fraction; (iii) vastly overpredicts the H i mass function; (iv) predicts high-z stellar mass functions that have too many low-mass galaxies and too few high-mass ones and (v) predicts a redshift evolution of the stellar mass density and the star formation history that are in moderate disagreement. These results suggest that some important processes are still missing in the current model family, and we discuss a number of possible solutions to solve the discrepancies, such as interactions between galaxies and dark matter haloes, tidal stripping, the bimodal accretion of gas, preheating and a redshift-dependent initial mass function.
A Cosmology Calculator for the World Wide Web

A cosmology calculator that computes times and distances as a function of redshift for user- defined cosmological parameters has been made available online. This paper gives the formulae used by the cosmology calculator and discusses some of its implementation. A version of the calculator that allows one to specify the equation-of-state parameter w and , and one for converting the light-travel times usually given in � w the popular press into redshifts, is also located at the same site.
Entrepreneurial Enterprises, Large Established Firms and Other Components of the Free-Market Growth Machine*

The paper studies the principal influences accounting for the unprecedented growth and innovation performance of the free-market economies. It indicates that vigorous oligopolistic competition, particularly in high-tech industries, forces firms to keep innovating in order to survive. This leads them to internalize innovative activities rather than leaving them to independent inventors, and turns invention into an assembly-line process. The bulk of private R&D spending is shown to come from a tiny number of very large firms. Yet the revolutionary breakthroughs continue to come predominantly from small entrepreneurial enterprises, with large industry providing streams of incremental improvements that also add up to major contributions. Moreover, these firms voluntarily disseminate much of their innovative technology widely and rapidly, both as a major revenue source and in exchange for complementary technological property of other firms, including direct competitors. This helps to internalize the externalities of innovation and speeds elimination of obsolete technology. Some policy implications for industrialized and developing countries are also discussed.
Diversity science: Why and how difference makes a difference.

This article proposes that addressing the complex ethnic and racial issues of the 21st century will require a diversity science. A diversity science will consider how people create, interpret, and maintain group differences among individuals, as well as the psychological and societal consequences of these distinctions. A diversity science will recognize that these significant social distinctions (in the case of this article, race and ethnicity) are not simply natural, neutral, or abstract. Instead they are created and re-created in the process of everyday social interactions that are grounded in historically derived ideas and beliefs about difference and in a set of practices and institutions that reflect these ideas and beliefs and that therefore shape psychological experience and behavior. According to this “sociocultural” framework, psychological experience and behavior, in turn, reinforce particular cultural and structural realities. As an initial step toward a diversity science, this article reviews ...
First Measurements of the Polarization of the Cosmic Microwave Background Radiation at Small Angular Scales from CAPMAP

Polarization results from the Cosmic Anisotropy Polarization MAPper (CAPMAP) experiment are reported. These are based on 433 hr, after cuts, observing a 2 deg2 patch around the north celestial pole with four 90 GHz correlation polarimeters coupled to optics defining 4' beams. The E-mode flat band-power anisotropy within l = 940 is measured as 66 μK2; the 95% confidence level upper limit for B-mode power within l = 1050 is measured as 38 μK2.
Efficient Algorithms for Dynamic Allocation of Distributed Memory

We consider the problem of dynamically allocating and deallocating local memory resources among multiple users in a parallel or distributed system. Given a group of independent users and a collection of interconnected local memory devices, we want to render the fragmentation of the memory resources irrelevant by allowing any user to allocate space for his or her purposes as long as there is space available anywhere in the system. In effect, we would like it to appear to the users as though they are allocating memory from a single central pool of memory, even though the space is distributed throughout the system. Our goal is to devise an on-line allocation algorithm that minimizes two cost measures: first, the fraction of unused space , which arises due to fragmentation of the memory; second, the slowdown needed by the system to service user requests, which arises due to the contention for access to the memory devices. We solve this distributed dynamic allocation problem in near-optimal fashion by devising an algorithm that allows the memory to be used to 100% of capacity despite the fragmentation and guarantees that service delays will always be within a constant factor of optimal. The algorithm is completely on-line (no foreknowledge of user activity is assumed) and can accommodate any sequence of allocations and deallocations by the users that does not violate global memory bounds. We also consider the distributed dynamic allocation problem in the more restrictive setting where the local memory devices are connected by a low-degree fixed-connection network, rather than being fully interconnected. In this case, communication costs must be more explicitly considered in our allocation algorithms. We give allocation algorithms for butterfly and hypercube networks, and prove necessary and sufficient conditions on the total amount of memory space needed for near-optimal algorithms to exist.
Effect of meso-substituents on the osmium tetraoxide reaction and pinacol-pinacolone rearrangement of the corresponding vic-dihydroxyporphyrins.

To investigate the effects of electron-donating and electron-withdrawing substituents upon the reaction of porphyrins with osmium tetraoxide, and the pinacol−pinacolone rearrangement of the resulting diols, a series of meso-substituted porphyrins were prepared by total synthesis. Porphyrins with electron-donating substitutents at the meso-positions gave vic-dihydroxychlorins in which the adjacent pyrrole subunit was predominantly oxidized. No such selectivity was observed in a porphyrin containing a methoxycarbonyl as the electron-withdrawing group, whereas a formyl substituent again resulted in oxidation at the pyrrole unit adjacent to the meso-substituent. Under pinacol−pinacolone conditions, vic-dihydroxy chlorins containing 4-methoxyphenyl or 3,5-dimethoxyphenyl groups at the meso-position showed preferential migration of the ethyl group over the methyl group to give 8-ketochlorins, whereas the diol with an n-heptyl substituent under similar reaction conditions gave both 7- and 8-ketochlorins. In cont...
Radical processes in the pyrolysis of acetylene

The literature on the pyrolysis of acetylene below 1000 K is reviewed and it is shown that the reaction is a radical chain polymerization initiated by H atoms. The induction period is examined and shown to arise from a rapid autocatalysis produced by the very first product, vinyl acetylene. Data from studies of acetylene polymerization induced by vinyl acetylene and styrene are examined and shown to be in good qualitative agreement with the radical chain process presented. Measured and where needed, estimated rate constants are given to produce numerical estimates of chain length, rates of polymerization, induction period, and rates of initiation. It is further shown that all the products of the polymerization are capable of efficiently initiating chains in the system. An examination of the possible kinetics of vinylidene shows that it does not play any role in acetylene chemistry.
Neoclassical Growth Theory and Heterodox Growth Theory: Opportunities For (and Obstacles To) Greater Engagement

This article explores the possibilities for greater engagement between neoclassical and heterodox growth theorists. Simple structural models are used to identify the essential “mechanics” of the growth process in both the neoclassical and heterodox traditions, and these are shown to point to important areas of theoretical overlap and even observational equivalence. In particular, the interaction of trend and cycle — and more specifically, the influence of demand on long-run growth — is identified as an emerging “common front” in growth theory. Rhetorical and sociological obstacles to greater engagement are identified, but it is argued that these should not be allowed to thwart profitable interactions among researchers from different traditions.
Compact antennas for UWB applications

A report on an investigation of spherical, disc, and half-disc antennas in the frequency and time domains with the objective of developing small planar versions of the antennas. These antennas have an omni-directional impulse response in azimuth and pulse duration of 0.5-0.65 nanoseconds. In addition, the measured data show a reasonable peak received signal in a pulse communication link using two identical antennas.
A Most Energetic Type Ic Supernova: SN 2003L

We present extensive radio observations of SN2003L, the most luminous and energetic Type Ic radio supernova with the exception of SN 1998bw. Using radio data, we are able to constrain the physical parameters of the supernova, including the velocity and energy of the fastest ejecta, the temporal evolution of the magnetic field, and the density profile of the surrounding medium. We highlight the extraordinary properties of the radio emission with respect to the supernova’s normal characteristics within optical bands. We find that although the explosion does not show evidence for a significant amount of relativistic ejecta, it produces a radio luminosity which is comparable to that seen in the unusual SN1998bw. Using SN2003L as an example, we comment briefly on the broad diversity of type Ic properties and the associated implications for progenitor models.
SUperposition Noisy Network Coding

We present a superposition coding scheme for communication over a network, which combines partial decode and forward with noisy network coding. This hybrid scheme is termed as superposition noisy network coding. The scheme is designed and analyzed for a single relay channel, single source multicast network and multiple source multicast network. The achievable rate region is determined for each case. The special cases of Gaussian single relay channel and two way relay channel are analyzed for superposition noisy network coding. The achievable rate of the proposed scheme is higher than the existing schemes of noisy network coding and compress-forward.
Model Predictive and Genetic Algorithm-Based Optimization of Residential Temperature Control in the Presence of Time-Varying Electricity Prices

This paper presents an optimal control algorithm for residential temperature regulation. The combination of concepts from system identification, model-predictive control, and genetic algorithms result in an optimization methodology capable of achieving an acceptable compromise between comfort and cost in the presence of constant as well as time-varying electricity prices. Simulation results demonstrate that the proposed approach has the potential to achieve substantial energy savings and cost reductions while maintaining acceptable comfort levels with minimal consumer participation.
Fluorous-tethered amine bases for organic and parallel synthesis: scope and limitations

Abstract The synthesis of fluorous-tethered amine bases is described. These novel fluorous-tethered reagents promote reactions, remove acidic by-products, and scavenge electrophiles. They are readily separated from the reaction mixture by solid phase extraction on a novel mixed sorbent SPE (SCX/fluorous silica gel) delivering products in high yields and purities.
Culture of murine brain microvascular endothelial cells that maintain expression and cytoskeletal association of tight junction-associated proteins.

A readily obtainable in vitro paradigm of the blood-brain barrier (BBB) would offer considerable benefits. Toward this end, in this study, we describe a novel method for purifying murine brain microvascular endothelial cells (BMEC) for culture. The method uses limited collagenase-dispase digestion of enriched brain microvessels, followed by immunoisolation of digested, microvascular fragments by magnetic beads coated with antibody to platelet-endothelial cell adhesion molecule-1. When plated onto collagen IV-coated surfaces, these fragments elaborated confluent monolayers of BMEC that expressed, as judged by immunocytochemistry, the adherens junction-associated proteins, VE-cadherin and β-catenin, as well as the tight junction (TJ)-associated proteins, claudin-5, occludin, and zonula occludin-1 (ZO-1), in concentrated fashion along intercellular borders. In contrast, cultures of an immortalized and transformed line of murine brain capillary-derived endothelial cells, bEND.3, displayed diffuse cytoplasmic localization of occludin and ZO-1. This difference in occludin and ZO-1 staining between the two endothelial cell types was also reflected in the extent of association of these proteins with the detergent-resistant cytoskeletal framework (CSK). Although both occludin and ZO-1 largely partitioned with the CSK fraction in BMEC, they were found predominantly in the soluble fraction of bEND.3 cells, and claudin-5 was found associated equally with both fractions in BMEC and bEND.3 cells. Moreover, detergent-extracted cultures of the BMEC retained pronounced immunostaining of occludin and ZO-1, but not claudin-5, along intercellular borders. Because both occludin and ZO-1 are thought to be functionally coupled to the detergent-resistant CSK and high expression of TJs is considered a seminal characteristic of the BBB, these results impart that this method of purifying murine BMEC provides a suitable platform to investigate BBB properties in vitro.
Parallel Synthesis of Oxazolines and Thiazolines by Tandem Condensation-Cyclodehydration of Carboxylic Acids With Amino Alcohols and Aminothiols.

A combinatorial library of oxazolines and thiazolines was synthesized in moderate to excellent yields using a newly developed methodology. Free carboxylic acids were directly condensed with amino alcohols and aminothiols in the presence of 3-nitrophenylboronic acid as a dehydration catalyst. The library synthesis illustrates the scope of this process: After traditional reaction optimization, a total of 17 oxazolines and 6 thiazolines were successfully prepared in a 24-reaction setup in a Radleys GreenHouse parallel synthesizer. The yields of the parallel reactions ranged from moderate to excellent, depending largely on carboxylate reactivity and functionalization, and generally exceeded those of the traditional reaction setup. The target compounds were isolated in high purities (average purity is 96% according to GC analysis) after passing reaction mixtures through short PrepSep SPE Florisil cartridges.
Bioinformatics at microsoft research

The advancement of the life sciences in the last twenty years has been the story of increasing integration of computing with scientific research, and this trend is set to transform the practice of science in our lifetimes. Conversely, biological systems are a rich source of ideas that will transform the future of computing. In addition to supporting academic research in the life sciences, Microsoft Research is a source of tools and technologies well suited to the needs of basic scientific research. Current projects include new languages to simplify data extraction and processing, tools for scientific workflows, and biological visualization. Computer science researchers also bring new perspectives to problems in biology, such as the use of schema-matching techniques in merging ontologies, machine learning in vaccine design, and process algebra in understanding metabolic pathways.
Autonomous return on investment analysis of additional processing resources

As the use of virtualisation and partitioning grows, it becomes possible to deploy a multi-tier web-based application with a variable amount of computing power. This introduces the possibility of provisioning only for a minimum workload, with the intention of renting more resources as necessary, but it also creates the problem of quickly and accurately identifying when more resources are needed or unneeded resources are being paid for. This paper presents a machine learning based approach to handling this problem. An autonomous adaptive agent learns to predict the gain (or loss) that would result from more (or less) resources; this agent uses only low-level system statistics, rather than relying on custom instrumentation of the operating system or middleware. Our agent is fully implemented and evaluated on a publicly available multi-machine, multi-process distributed system (the online transaction processing benchmark TPC-W). We show that our adaptive agent is competitive with any static choice of computing resources over a variety of test workloads. We also show that the agent outperforms each static choice in at least one case, implying that it is well suited for a situation where the workload is unknown.
Synthesis of C-15 Vindoline Analogues by Palladium-Catalyzed Cross-Coupling Reactions

Described are general protocols for the rapid construction of various C-15-substituted analogues of vindoline using palladium-catalyzed cross-coupling reactions. The required bromo- and iodovindolines were prepared in high yield by the reaction of vindoline with N-bromosuccinimide or N-iodosuccinimide, respectively. The study not only led to the preparation of a number of structurally novel vindoline analogues but also opens the door to new strategies for the synthesis of vinblastine, vincristine, and related anticancer agents. Also described is the conversion of ent-tabersonine to ent-vindoline.
Application of subspace projection approaches for reduced-order modeling of electromagnetic systems

Subspace projection approaches, including the Pade/spl acute/ via Lanczos (PVL), Krylov, and rational Krylov algorithms, are used for reduced-order modeling of wide-band electromagnetic systems. The properties of these algorithms are discussed. A frequency segmentation technique has also been used with the Lanczos algorithm to obtain benchmark data of electromagnetic fields and for scattering parameter extraction from the calculated electromagnetic field values. From the various techniques, the combined PVL/frequency segmentation technique is the most promising for efficient and accurate modeling of electromagnetic systems.
Independence from obfuscation: A semantic framework for diversity

A set of replicas is diverse to the extent that they implement the same functionality but differ in their implementation details. Diverse replicas are less likely to succumb to the same attacks, when attacks depend on memory layout and/or other implementation details. Recent work advocates using mechanical means, such as program rewriting, to create such diversity. A correspondence between the specific transformations being employed and the attacks they defend against is often provided, but little has been said about the overall effectiveness of diversity per se in defending against attacks. With this broader goal in mind, this paper gives a precise characterization of attacks, applicable to viewing diversity as a defense, and also shows how mechanically-generated diversity compares to a well-understood defense: type checking.
OPTICAL SENSING FOR GAS DETECTION IN ENCLOSED ROADWAYS

Detection of vehicle emissions and other gases will be an important part of the future ITS infrastructure, especially for enclosed roadways. The recently passed Intermodal Surface Transportation Efficiency Act and the Clean Air Amendments provide great incentive for the collection of emissions data. Enclosed roadways can use such data to control ventilation systems and detect hazardous substances. This paper examines the feasibility of using optical gas sensors for real-time control of enclosed roadways as well as regional environmental monitoring of mobile source emissions.© (1995) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Psychological Factors and Stock Option Exercise

We investigate stock option exercise decisions by over 50,000 employees at seven corporations. Controlling for economic factors, psychological factors influence exercise. Consistent with psychological models of beliefs, employees exercise in response to stock price trends—exercise is positively related to stock returns during the preceding month and negatively related to returns over longer horizons. Consistent with psychological models of values that include reference points, employee exercise activity roughly doubles when the stock price exceeds the maximum price attained during the previous year.
Behavior of Structures During Earthquakes

Behavior is described by response spectrum curves which show effect of size and distance of earthquake and period and damping of structure; high elastic stresses are developed during strong ground motion; type of limit design is indicated.
Semantic Rule Based Text Generation

This paper presents a semantically oriented, rule based method for single sentence text generation and discusses its implementation in the Kafka generator. This generator is part of the XCALIBUR natural language interface developed at CMU to provide natural language facilities for a wide range of expert systems and data bases. Kafka takes as input the knowledge representation used in XCALIBUR system and incrementally transforms it first into conceptual dependency graphs and then into English.1
In a World That Counts: Clustering and Detecting Fake Social Engagement at Scale

How can web services that depend on user generated content discern fake social engagement activities by spammers from legitimate ones? In this paper, we focus on the social site of YouTube and the problem of identifying bad actors posting inorganic contents and inflating the count of social engagement metrics. We propose an effective method, Leas (Local Expansion at Scale), and show how the fake engagement activities on YouTube can be tracked over time by analyzing the temporal graph based on the engagement behavior pattern between users and YouTube videos. With the domain knowledge of spammer seeds, we formulate and tackle the problem in a semi-supervised manner --- with the objective of searching for individuals that have similar pattern of behavior as the known seeds --- based on a graph diffusion process via local spectral subspace. We offer a fast, scalable MapReduce deployment adapted from the localized spectral clustering algorithm. We demonstrate the effectiveness of our deployment at Google by achieving a manual review accuracy of 98% on YouTube Comments graph in practice. Comparing with the state-of-the-art algorithm CopyCatch, Leas achieves 10 times faster running time on average. Leas is now actively in use at Google, searching for daily deceptive practices on YouTube's engagement graph spanning over a billion users.