cssi/SciSciGPT-SciSciNet huggingface dataset:
Using expander graphs to find vertex connectivity

The (vertex) connectivity κ of a graph is the smallest number of vertices whose deletion separates the graph or makes it trivial. We present the fastest known algorithm for finding κ. For a digraph with n vertices, m edges and connectivity κ the time bound is O((n p min{κ5/2;, κn3/4;})m). This improves the previous best bound of O((n p min{κ3, κn})m). For an undirected graph both of these bounds hold with m replaced by κn. Expander graphs are useful for solving the following subproblem that arises in connectivity computation: A known set R of vertices contains two large but unknown subsets that are separated by some unknown set S of κ vertices; we must find two vertices of R that are separated by S.
Model‐Based Visualization of Temporal Abstractions

We describe a new conceptual methodology and related computational architecture called Knowledge-based Navigation of Abstractions for Visualization and Explanation (KNAVE). KNAVE is a domain-independent framework specific to the task of interpretation, summarization, visualization, explanation, and interactive exploration, in a context-sensitive manner, of time-oriented raw data and the multiple levels of higher level, interval-based concepts that can be abstracted from these data. The KNAVE domain-independent exploration operators are based on the relations defined in the knowledge-based temporal-abstraction problem-solving method, which is used to abstract the data, and thus can directly use the domain-specific knowledge base on which that method relies. Thus, the domain-specific semantics are driving the domain-independent visualization and exploration processes, and the data are viewed through a filter of domain-specific knowledge. By accessing the domain-specific temporal-abstraction knowledge base and the domain-specific time-oriented database, the KNAVE modules enable users to query for domain-specific temporal abstractions and to change the focus of the visualization, thus reusing for a different task (visualization and exploration) the same domain model acquired for abstraction purposes. We focus here on the methodology, but also describe a preliminary evaluation of the KNAVE prototype in a medical domain. Our experiment incorporated seven users, a large medical patient record, and three complex temporal queries, typical of guideline-based care, that the users were required to answer and/or explore. The results of the preliminary experiment have been encouraging. The new methodology has potentially broad implications for planning, monitoring, explaining, and interactive data mining of time-oriented data.
Effects of Atmosphere on Slewing Control of a Flexible Structure

Air drag forces are introduced into the equations for a slewing control maneuver of a flexible structure to assess the effects of atmosphere on the controller design. Simulated modal parameters and transient responses are compared with experiments in normal atmosphere and vacuum. Analytical techniques for control laws are examined and verified. Physical insight into the air damping is gained so that results in vacuum can be extrapolated from results in air.
Synthesis of 2′-deoxy-β-D-ribofuranosyl imidazole and thiazole C-nucleosides

A synthetic route to 2-carbamoyl-4-(2′-deoxy-β-D-ribofuranosyl)imidazole 3, starting from 2-deoxy-3,5-di-O-toluoyl-β-D-ribofuranosyl cyanide 4, was developed. The key steps are reduction of the cyano group of compound 4 to a formyl and subsequent condensation with tosylmethyl isocyanide to yield the formamido derivative 7, which was dehydrated to an isocyanide and ring closed with either ammonia or a primary amine to yield protected C-4 linked imidazolyl deoxyribosyl derivatives 9a–c. Ring closure with H2S followed by removal of the toluoyl protecting groups with ammonia gave 5-(2′-deoxy-β-D-ribofuranosyl)thiazole 11. A cyano group can be introduced at C-2 of the imidazole nucleosides by way of the reagent N-cyano-4-(dimethylamino)pyridinium bromide. Subsequent hydrolysis of the cyano functional group with alkaline hydrogen peroxide yields a carboxamide substituent. All of the transformations were able to be carried out without affecting the β-configuration at the anomeric carbon. A p-nitrophenylethyl protecting group was introduced at N-3 of the imidazole during ring closure in order to obtain a protected derivative that could be selectively modified at the deoxyribosyl (erythro-pentofuranosyl) hydroxy groups.
System architecture for process automation: Review and trends

Abstract New developments in information technologies are radically transforming process automation. Their impact and benefit derive both from these technologies individually and from their convergence in new system architecture concepts. This paper reviews how process automation system architectures have evolved and discusses future trends. We draw an analogy between the synergistic new technologies being developed today and the technology landscape of the early 1970s—characterized by the near-simultaneous appearance of microprocessors, communication networks, CRT displays—that resulted in the first DCS systems (in particular, the Honeywell TDC2000). Emerging technologies highlighted include wireless, embedded devices, service-oriented architecture, and application infrastructures.
Fast and scalable inference of multi-sample cancer lineages

Somatic variants can be used as lineage markers for the phylogenetic reconstruction of cancer evolution. Since somatic phylogenetics is complicated by sample heterogeneity, novel specialized tree-building methods are required for cancer phylogeny reconstruction. We present LICHeE (Lineage Inference for Cancer Heterogeneity and Evolution), a novel method that automates the phylogenetic inference of cancer progression from multiple somatic samples. LICHeE uses variant allele frequencies of somatic single nucleotide variants obtained by deep sequencing to reconstruct multi-sample cell lineage trees and infer the subclonal composition of the samples. LICHeE is open source and available at http://viq854.github.io/lichee .
An envelope-following method for the efficient transient simulation of switching power and filter circuits

The transient behavior of circuits like switching power converters and switched capacitor filters are expensive to simulate because they are clocked at a frequency whose period is orders of magnitude smaller than the time interval of interest to the designer. It is possible to reduce the simulation time without compromising accuracy by exploiting the fact that the behavior of such a circuit in a given high-frequency clock cycle is similar, but not identical, to its behavior in the preceding and following cycles. In particular, the envelope of the high-frequency clock can be followed by accurately computing the circuit behavior over occasional cycles. The authors describe the implementation of an envelope-following method that is particularly efficient for switching power and filter circuits, and they present results demonstrating the method's effectiveness. >
Service Adoption and Pricing of Content Delivery Network (CDN) Services

Content delivery networks (CDNs) are a vital component of the Internet's content delivery value chain, servicing nearly a third of the Internet's most popular content sites. However, in spite of their strategic importance, little is known about the optimal pricing policies or adoption drivers of CDNs. We address these questions using analytic models of CDN pricing and adoption under Markovian traffic and extend the results to bursty traffic using numerical simulations. When traffic is Markovian, we find that CDNs should provide volume discounts to content providers. In addition, the optimal pricing policy entails lower emphasis on value-based pricing and greater emphasis on cost-based pricing as the relative density of content providers with high outsourcing costs increases. However, when traffic is bursty and content providers have varying levels of traffic burstiness, volume discounts may be suboptimal and may even be replaced by volume taxes. Finally, when there is heterogeneity in burstiness across content providers, a pricing policy that accounts for both the mean and variance in traffic such as percentile-based pricing is more profitable than traditional volume-based pricing (metering bytes delivered in a given time window). This finding is in contrast to the current practices of many CDN firms that use traditional volume-based pricing.
Rent-seeking and innovation

Innovations and their adoption are the keys to growth and development. Innovations are less socially useful, but more profitable for the innovator, when they are adopted slowly and the innovator remains a monopolist. For this reason, rent-seeking, both public and private, plays an important role in determining the social usefulness of innovations. This paper examines the political economy of intellectual property, analyzing the trade-off between private and public rent-seeking. While it is true in principle that public rent-seeking may be a substitute for private rent-seeking, it is not true that this results always either in less private rent-seeking or in a welfare improvement. When the public sector itself is selfish and behaves rationally, we may experience the worst of public and private rent-seeking together.
A simple model of low-scale direct gauge mediation

We construct a calculable model of low-energy direct gauge mediation making use of the metastable supersymmetry breaking vacua recently discovered by Intriligator, Seiberg and Shih. The standard model gauge group is a subgroup of the global symmetries of the SUSY breaking sector and messengers play an essential role in dynamical SUSY breaking: they are composites of a confining gauge theory, and the holomorphic scalar messenger mass appears as a consequence of the confining dynamics. The SUSY breaking scale is around 100 TeV nevertheless the model is calculable. The minimal non-renormalizable coupling of the Higgs to the DSB sector leads in a simple way to a μ-term, while the B-term arises at two-loop order resulting in a moderately large tan β. A novel feature of this class of models is that some particles from the dynamical SUSY breaking sector may be accessible at the LHC.
Team Effectiveness 1997-2007: A Review of Recent Advancements and a Glimpse Into the Future:

The authors review team research that has been conducted over the past 10 years. They discuss the nature of work teams in context and note the substantive differences underlying different types of teams. They then review representative studies that have appeared in the past decade in the context of an enhanced input-process-outcome framework that has evolved into an inputs-mediators-outcome time-sensitive approach. They note what has been learned along the way and identify fruitful directions for future research. They close with a reconsideration of the typical team research investigation and call for scholars to embrace the complexity that surrounds modern team-based organizational designs as we move forward.
Synchronization of Coupled Oscillators is a Game

The purpose of this paper is to understand phase transition in noncooperative dynamic games with a large number of agents. Applications are found in neuroscience, biology, and economics, as well as traditional engineering applications. The focus of analysis is a variation of the large population linear quadratic Gaussian (LQG) model of Huang et al. 2007, comprised here of a controlled N-dimensional stochastic differential equation model, coupled only through a cost function. The states are interpreted as phase angles for a collection of heterogeneous oscillators, and in this way the model may be regarded as an extension of the classical coupled oscillator model of Kuramoto. A deterministic PDE model is proposed, which is shown to approximate the stochastic system as the population size approaches infinity. Key to the analysis of the PDE model is the existence of a particular Nash equilibrium in which the agents "opt out' of the game, setting their controls to zero, resulting in the "incoherence' equilibrium. Methods from dynamical systems theory are used in a bifurcation analysis, based on a linearization of the partial differential equation (PDE) model about the incoherence equilibrium. A critical value of the control cost parameter is identified: above this value, the oscillators are incoherent; and below this value (when control is sufficiently cheap) the oscillators synchronize. These conclusions are illustrated with results from numerical experiments.
Second cancer risk in childhood cancer survivors treated with intensity-modulated radiation therapy (IMRT).

Background Treatment with radiotherapy (RT) is associated with an increased risk of second malignant neoplasms (SMNs) in childhood cancer survivors; it is unclear how treatment with intensity-modulated radiation therapy (IMRT) impacts this risk. We provide the first report of SMN risk in a cohort of childhood cancer survivors treated with IMRT. Procedure Retrospective review of patients ≤21 years of age treated with IMRT at Memorial Sloan Kettering Cancer Center between December 1998 and February 2009. Eligible patients survived at least 5 years from IMRT initiation. The risk of SMN was assessed via standardized incidence ratios (SIRs) and excess absolute risk (EAR). The cumulative incidence was estimated using methods for competing risks. Results Among 242 patients, six developed SMNs: four developed second solid cancers (all within the radiation field), and two developed myelodysplastic syndrome. Median time from IMRT initiation to a second solid cancer was 7.2 years (range, 6.8–9.5), with a 10-year cumulative incidence of 3.3% (95% confidence interval [CI], 1.0–7.8%), SIR of 11.4 (95% CI, 3.1–29.2) and EAR of 1.8 per 1,000 person-years (95% CI, −0.1 to 3.8). Conclusions Longer follow-up is required to determine how the risk of SMN after IMRT compares to other modalities of radiation treatment, such as proton therapy. This study provides a preliminary report, which will serve as a baseline for future longitudinal analyses of SMN risk after IMRT. Pediatr Blood Cancer 2015;62:311–316. © 2014 Wiley Periodicals, Inc.
Young children's analogical problem solving: gaining insights from video displays.

Abstract This study examined how toddlers gain insights from source video displays and use the insights to solve analogous problems. The sample of 2- and 2.5-year-olds viewed a source video illustrating a problem-solving strategy and then attempted to solve analogous problems. Older, but not younger, toddlers extracted the problem-solving strategy depicted in the video and spontaneously transferred the strategy to solve isomorphic problems. Transfer by analogy from the video was evident only when the video illustrated the complete problem goal structure, including the character’s intention and the action needed to achieve a goal. The same action isolated from the problem-solving context did not serve as an effective source analogue. These results illuminate the development of early representation and processes involved in analogical problem solving. Theoretical and educational implications are discussed.
When does rigorous impact evaluation make a difference? : the case of the millennium villages

When is the rigorous impact evaluation of development projects a luxury, and when a necessity? The authors study one high-profile case: the Millennium Villages Project (MVP), an experimental and intensive package intervention to spark sustained local economic development in rural Africa. The authors illustrate the benefits of rigorous impact evaluation in this setting by showing that estimates of the project's effects depend heavily on the evaluation method. Comparing trends at the MVP intervention sites in Kenya, Ghana, and Nigeria to trends in the surrounding areas yields much more modest estimates of the project's effects than the before-versus-after comparisons published thus far by the MVP. Neither approach constitutes a rigorous impact evaluation of the MVP, which is impossible to perform due to weaknesses in the evaluation design of the project's initial phase. These weaknesses include the subjective choice of intervention sites, the subjective choice of comparison sites, the lack of baseline data on comparison sites, the small sample size, and the short time horizon. The authors describe one of many ways that the next wave of the intervention can be designed to allow proper evaluation of the MVP's impact at little additional cost.
High-ordered random walks and generalized laplacians on hypergraphs

Despite of the extreme success of the spectral graph theory, there are relatively few papers applying spectral analysis to hypergraphs. Chung first introduced Laplacians for regular hypergraphs and showed some useful applications. Other researchers treated hypergraphs as weighted graphs and then studied the Laplacians of the corresponding weighted graphs. In this paper, we aim to unify these very different versions of Laplacians for hypergraphs. We introduce a set of Laplacians for hypergraphs through studying high-ordered random walks on hypergraphs. We prove the eigenvalues of these Laplacians can effectively control the mixing rate of high-ordered random walks, the generalized distances/diameters, and the edge expansions.
The payoff to school selectivity: An application of Dale and Krueger’s method to MBA programs

Abstract Many studies find a notable return to college quality. Dale and Krueger, 2002 , Dale and Krueger, 2011 only do until they address selection bias concerns by proxying for ambition and by matching students with similar admission outcomes but different matriculation decisions. Although we employ similar methodologies to Dale and Krueger, we find substantial returns to MBA program selectivity.
Characteristics of Elm Activity and Fueling Efficiency of Pellet Injection from Different Locations on DIII-D

Pellet injection from several different locations has been used on the DIII-D tokamak to study core fueling and transport in H-mode and L-mode plasmas. These experiments have provided a variety of conditions in which to examine the fueling efficiency and edge localized mode (ELM) interaction with pellets injected into DIII-D plasmas. The fueling efficiency, defined as the total increase in number of plasma electrons divided by the number of pellet fuel atoms, is determined by measurements of density profiles before and just after pellet injection. New injection ports on the DIII-D inner wall enable high field side (HFS) pellet injection from both the midplane and 30 cm above the midplane. These ports, in addition to the previously existing top vertical ports and outside midplane port, enable a comparison of the effect of injection location on fueling efficiency and ELM activity. We find that the ELMs triggered from HFS injected pellets and vertical HFS injected pellets are similar to the nominal background ELMs in ELMing H-mode plasmas. In contrast, the low field side (LFS) injected pellets trigger large-magnitude ELMs that lead to a strong reduction in fueling efficiency. The fueling efficiency of the HFS injected pellets is found to be significantly higher than with the LFS injected pellets and remains high even with significant heating power.
Truth Discovery with Multiple Conflicting Information Providers on the Web

The World Wide Web has become the most important information source for most of us. Unfortunately, there is no guarantee for the correctness of information on the Web. Moreover, different websites often provide conflicting information on a subject, such as different specifications for the same product. In this paper, we propose a new problem, called Veracity, i.e., conformity to truth, which studies how to find true facts from a large amount of conflicting information on many subjects that is provided by various websites. We design a general framework for the Veracity problem and invent an algorithm, called TRUTHFlNDER, which utilizes the relationships between websites and their information, i.e., a website is trustworthy if it provides many pieces of true information, and a piece of information is likely to be true if it is provided by many trustworthy websites. An iterative method is used to infer the trustworthiness of websites and the correctness of information from each other. Our experiments show that TRUTHFlNDER successfully finds true facts among conflicting information and identifies trustworthy websites better than the popular search engines.
Queuing theoretic analysis of power-performance tradeoff in power-efficient computing

In this paper we study the power-performance relationship of power-efficient computing from a queuing theoretic perspective. We investigate the interplay of several system operations including processing speed, system on/off decisions, and server farm size. We identify that there are oftentimes 'sweet spots' in power-efficient operations: there exist optimal combinations of processing speed and system settings that maximize power efficiency. For the single server case, a widely deployed threshold mechanism is studied. We show that there exist optimal processing speed and threshold value pairs that minimize the power consumption. This holds for the threshold mechanism with job batching. For the multi-server case, it is shown that there exist best processing speed and server farm size combinations.
Model atmospheres of Mercury

Mercury atmospheric models for preliminary environmental criteria to be used in spacecraft design and engineering trade-off studies
Fracture behavior of directionally solidified Y3Al5O12/Al2O3 eutectic fiber

The strength and fracture of a directionally solidified Y3Al5O12/Al2O3 eutectic fiber were investigated. The fiber was grown continuously by an edge-defined film-fed growth technique. The microstructure was characterized using X-ray diffraction, scanning electron microscopy, and energy-dispersive spectroscopy. The tensile strength and Weibull's modulus of the eutectic fibers were determined in the as-fabricated state and after extended thermal exposure at 1460°C in air. Fractographic analysis was used to identify and classify the strength-limiting mechanisms. The fracture toughness and crack growth behavior were characterized by an indentation technique. A fracture mechanics analysis was also used to establish the relationships between surface flaw size, tensile strength, and fracture toughness of the fiber.
Regional Bell Operating Company entry into long‐distance and non‐price discrimination against rival interexchange carriers: empirical evidence from panel data

The incentive of the Regional Bell Operating Companies (RBOCs) to degrade the quality of interstate access services, an essential input provided to rival long-distance carriers, once they begin offering long-distance services has been a controversial issue in the academic literature. Using a panel of state-level data over the years 1996–2001, this paper investigates whether the RBOCs engage in such ‘non-price discrimination’ upon entering the long-distance market. The results suggest the RBOCs improve the quality of some of their interstate access service offerings before entering the interexchange market, but begin degrading the quality of these services immediately afterward. Copyright © 2003 John Wiley & Sons, Ltd.
On D=5 super Yang-Mills theory and (2,0) theory

We discuss how D = 5 maximally supersymmetric Yang-Mills theory (MSYM) might be used to study or even to define the (2, 0) theory in six dimensions. It is known that the compactification of (2, 0) theory on a circle leads to D = 5 MSYM. A variety of arguments suggest that the relation can be reversed, and that all of the degrees of freedom of (2, 0) theory are already present in D = 5 MSYM. If so, this relation should have consequences for D = 5 SYM perturbation theory. We explore whether it might imply all orders finiteness, or else an unusual relation between the cutoff and the gauge coupling. S-duality of the reduction to D = 4 may provide nonperturbative constraints or tests of these options.
An analog decoding BGO block detector using circular photomultipliers

This is a positron camera detector design study using quadrant sharing of circular phototubes and optically cross-coupled BGO scintillation crystals. The goal is to design a very high spatial resolution detector using the larger and less expensive circular phototubes, so that the high production cost of high spatial resolution, multi-slice positron cameras may be lowered. Theoretical calculations and experimental studies have been performed using 19 mm diameter phototubes. The study shows that (a) BGO detector-pitch in the range of 2.2/spl times/2.2 mm to 3.0/spl times/3.0 mm (transaxial x axial) can be decoded with these 19 mm diameter phototubes, and (b) it is possible to achieve very uniform signal pulse-height for all the BGO crystals in the block with this design, even though there are relatively large air-gaps between circular phototubes. This study shows that very high spatial resolution, approaching the theoretical resolution of PET imaging, can be achieved using the cheaper 19 mm circular phototubes. >
Enantioselective synthesis of a 3'-dephenylcryptophycin synthon

Abstract An enantioselective synthesis of tert-butyl (5S,6R)-(E)-5-tert-butyldimethylsilyloxy-6-methyl-2,7-octadienoate, a precursor for the synthesis of the antimitotic macrolides cryptophycin A and arenastatin A (cryptophycin-24), is presented. The key step in the reaction sequence features a crotyl boration that sets both stereocenters that become the C16 hydroxyl and C1′ methyl in the cryptophycins. Homologation of the terminal olefin via a Heck reaction is presented.
Performance Analysis of Cognitive Radio Systems under QoS Constraints and Channel Uncertainty

In this paper, performance of cognitive transmission over time-selective flat fading channels is studied under quality of service (QoS) constraints and channel uncertainty. Cognitive secondary users (SUs) are assumed to initially perform channel sensing to detect the activities of the primary users, and then attempt to estimate the channel fading coefficients through training. Energy detection is employed for channel sensing, and different minimum mean-square-error (MMSE) estimation methods are considered for channel estimation. In both channel sensing and estimation, erroneous decisions can be made, and hence, channel uncertainty is not completely eliminated. In this setting, performance is studied and interactions between channel sensing and estimation are investigated. Following the channel sensing and estimation tasks, SUs engage in data transmission. Transmitter, being unaware of the channel fading coefficients, is assumed to send the data at fixed power and rate levels that depend on the channel sensing results. Under these assumptions, a state-transition model is constructed by considering the reliability of the transmissions, channel sensing decisions and their correctness, and the evolution of primary user activity which is modeled as a two-state Markov process. In the data transmission phase, an average power constraint on the secondary users is considered to limit the interference to the primary users, and statistical limitations on the buffer lengths are imposed to take into account the QoS constraints of the secondary traffic. The maximum throughput under these statistical QoS constraints is identified by finding the effective capacity of the cognitive radio channel. Numerical results are provided for the power and rate policies.
Adaptive Management to Protect Biodiversity: Best Available Science and the Endangered Species Act

Although flawed, the most powerful tool for protecting biodiversity in the United States is the Endangered Species Act, which requires the use of the best available science to ensure that endangered and threatened species are not put in jeopardy of extinction. Unfortunately, the best available science mandate is virtually meaningless and imposes no additional scientific rigor in agency decision making beyond what is normally required of administrative procedures. In this paper, we propose to define best available science in a way that shifts from a way of using science to a way of doing science, and a sound method of doing science for wildlife management and climate change is via the principles of adaptive management (1). Adaptive management, as a means of data accumulation and continuous learning, can fulfill and give teeth to the best available science mandate while increasing the adaptive capacity of wildlife management agencies to protect biodiversity in an unpredictably dynamic environment.
Modeling s-t path availability to support disaster vulnerability assessment of network infrastructure

The maintenance of system flow is critical for effective network operation. Any type of disruption to network facilities (arcs/nodes) potentially risks loss of service, leaving users without access to important resources. It is therefore an important goal of planners to assess infrastructures for vulnerabilities, identifying those vital nodes/arcs whose debilitation would compromise the most source-sink (s-t) interaction or system flow. Due to the budgetary limitations of disaster management agencies, protection/fortification and planning for the recovery of these vital infrastructure facilities is a logical and efficient proactive approach to reducing worst-case risk of service disruption. Given damage to a network, evaluating the potential for flow between s-t pairs requires assessing the availability of an operational s-t path. Recent models proposed for identifying infrastructure vital to system flow have relied on enumeration of all s-t paths to support this task. This paper proposes an alternative model constraint structure that does not require complete enumeration of s-t paths, providing computational benefits over existing models. To illustrate the model, an application to a practical infrastructure planning problem is presented.
TESTING THE NO-HAIR THEOREM WITH OBSERVATIONS IN THE ELECTROMAGNETIC SPECTRUM. II. BLACK HOLE IMAGES

According to the no-hair theorem, all astrophysical black holes are fully described by their masses and spins. This theorem can be tested observationally by measuring (at least) three different multipole moments of the spacetimes of black holes. In this paper, we analyze images of black holes within a framework that allows us to calculate observables in the electromagnetic spectrum as a function of the mass, spin, and, independently, the quadrupole moment of a black hole. We show that a deviation of the quadrupole moment from the expected Kerr value leads to images of black holes that are either prolate or oblate depending on the sign and magnitude of the deviation. In addition, there is a ring-like structure around the black hole shadow with a diameter of ~10 black hole masses that is substantially brighter than the image of the underlying accretion flow and that is independent of the astrophysical details of accretion flow models. We show that the shape of this ring depends directly on the mass, spin, and quadrupole moment of the black hole and can be used for an independent measurement of all three parameters. In particular, we demonstrate that this ring is highly circular for a Kerr black hole with a spin a 0.9 M, independent of the observer's inclination, but becomes elliptical and asymmetric if the no-hair theorem is violated. Near-future very long baseline interferometric observations of Sgr A* will image this ring and may allow for an observational test of the no-hair theorem.
Do ion tethered functional groups affect IL solvent properties? The case of sulfoxides and sulfones

The covalent incorporation of functional groups—specifically sulfoxide and sulfone—into the cation of imidazolium ionic liquids leads to significant, quantifiable changes in solvent parameters which in turn have important effects on the bulk properties of the materials.
A polarized HERA collider

Abstract A brief review is given of the status of nucleon spin structure functions as determined from polarized deep inelastic lepton-nucleon scattering, including current outstanding problems. The characteristics of a polarized HERA collider, some of the particle physics topics it could address, and the accelerator physics challenges it must meet are discussed.
Virtue and Criminal Negligence

This article addresses the contention of some prominent criminal law scholars – notably Jerome Hall and Glanville Williams – that negligence is an improper basis for the imposition of criminal punishment. An Aristotelian, virtue-ethics theory of punishment treats the inculcation of sound practical judgment as a function of punishment. The assessment of reasonable conduct implicit in negligence as a criterion of criminal fault fits comfortably within such a theory.
Qubit entanglement driven by remote optical fields

We examine the entanglement between two qubits, supposed to be remotely located and driven by independent quantized optical fields. No interaction is allowed between the qubits, but their degree of entanglement changes as a function of time. We report a collapse and revival of entanglement that is similar to the collapse and revival of single-atom properties in cavity QED.
A Simplified Design Model for Random Process Variability

A method for modeling the effects of random process variation through measured transistor current is introduced. The methodology culminates by modeling random current variation at a given operating point above threshold as a zero-mean Additive White Gaussian Noise (AWGN) current source with a standard deviation dependent on nominal operating current and design variables, the transistor sizes, W and L, and the transistor operating points, Vgs and Vds. The model has a simple posynomial form and is accurate compared to measured data within an RMS error of 5.4% for narrow-, wide-, short-, and long-channel transistors. The model's simplified form bridges the gap between existing statistical methods and circuit design. The efficacy of the model in the circuit design space will also be presented. In the analog domain, we will show that the contributions of this model can be used as a replacement for Monte Carlo methods for calculating circuit voltage and current variances. In the digital space, we will investigate the calculation of timing delay distributions. Results calculated via an alpha-power (?p) law model for average current show that scaling the supply voltage by ? results in an approximately 1/??p+1.1 scaling in the path-delay standard deviation for a 65-nm process.
Domain Walls on Singularities

We describe domain walls that live on A2 and A3 singularities. The walls are BPS if the singularity is resolved and non-BPS if it is deformed and fibered. We show that these domain walls may interpolate between vacua that support monopoles and/or vortices.
Polynomial stochastic games via sum of squares optimization

Stochastic games are an important class of games that generalize Markov decision processes to game theoretic scenarios. We consider finite state two-player zero-sum stochastic games over an infinite time horizon with discounted rewards. The players are assumed to have infinite strategy spaces and the payoffs are assumed to be polynomials. In this paper we restrict our attention to a very special class of games for which the single-controller assumption holds. It is shown that minimax equilibria and optimal strategies for such games may be obtained via semidefinite programming.
THE CENTRAL COMPONENT OF GRAVITATIONAL LENS Q0957+561

In 1981, a faint radio source (G') was detected near the center of the lensing galaxy of the famous "twin quasar" Q0957+561. It is still unknown whether this central radio source is a third quasar image or an active nucleus of the lensing galaxy, or a combination of both. In an attempt to resolve this ambiguity, we observed Q0957+561 at radio wavelengths of 13 cm, 18 cm, and 21 cm, using the Very Long Baseline Array in combination with the phased Very Large Array and the Green Bank Telescope. We measured the spectrum of G' for the first time and found it to be significantly different from the spectra of the two bright quasar images. This finding suggests that the central component is primarily or entirely emission from the foreground lens galaxy, but the spectrum is also consistent with the hypothesis of a central quasar image suffering free-free absorption. In addition, we confirm the previously-reported Very Long Baseline Interferometry position of G' just north of the optical center of the lens galaxy. The position slightly favors the hypothesis that G' originates in the lens, but is not conclusive. We discuss the prospects for further clarification of this issue.
Price Discrimination and Smuggling of AIDS Drugs

Patent-holding pharmaceutical companies are shown to be imperfectly able to charge differential prices for AIDS drugs due to the potential for black market exchange. Thus, greater segmentation in the international market through additional barriers to smuggling would induce firms to charge lower prices for AIDS drugs in poorer countries. Without these additional barriers, widespread drug distribution through mandated lower prices or weakened patent protection in the developing world would result in smuggling, undercutting demand in developed markets and reducing firms’ research incentives. By contrast, further market segmentation would allow policy makers to go beyond the induced price cuts and remove patent protection in many markets where the benefits to increased distribution would likely outweigh the losses to research incentives.
Contraceptive risk-taking in a medically-underserved, low-income population.

This study examines the phenomenon of contraceptive risk-taking, which is the non-use of contraception by women who are sexually active, fertile and not pregnant or trying to become pregnant. Based on a survey sample of low-income women in their childbearing years who had not received family planning care or advice from a doctor or clinic for at least three years, the study analyzed demographic predictors of contraceptive risk-taking, and also compared levels of contraceptive knowledge and pregnancy histories of noncontraceptors versus barrier method contraceptors. Contraceptive risk-taking was found to be higher for minority women, for parous women, for those age 30 and younger and for those whose knowledge of the fertility cycle is incorrect, but was found to be only weakly related to the women's marital status. Noncontraceptors were less knowledgeable concerning contraceptive methods and substantially more likely to have had previous unwanted pregnancies due to non-use of &ntraception, suggesting that ...
Violation of Bell's inequality with continuous spatial variables

We demonstrate an approach to violating Bell's inequality with the continuous spatial variables of entangled-photon pairs using simple optical components that manipulate the spatial parity of the transverse coordinate in one dimension.
Centromere reference models for human chromosomes X and Y satellite arrays

The human genome sequence remains incomplete, with multimegabase-sized gaps representing the endogenous centromeres and other heterochromatic regions. Available sequence-based studies within these sites in the genome have demonstrated a role in centromere function and chromosome pairing, necessary to ensure proper chromosome segregation during cell division. A common genomic feature of these regions is the enrichment of long arrays of near-identical tandem repeats, known as satellite DNAs, which offer a limited number of variant sites to differentiate individual repeat copies across millions of bases. This substantial sequence homogeneity challenges available assembly strategies and, as a result, centromeric regions are omitted from ongoing genomic studies. To address this problem, we utilize monomer sequence and ordering information obtained from whole-genome shotgun reads to model two haploid human satellite arrays on chromosomes X and Y, resulting in an initial characterization of 3.83 Mb of centromeric DNA within an individual genome. To further expand the utility of each centromeric reference sequence model, we evaluate sites within the arrays for short-read mappability and chromosome specificity. Because satellite DNAs evolve in a concerted manner, we use these centromeric assemblies to assess the extent of sequence variation among 366 individuals from distinct human populations. We thus identify two satellite array variants in both X and Y centromeres, as determined by array length and sequence composition. This study provides an initial sequence characterization of a regional centromere and establishes a foundation to extend genomic characterization to these sites as well as to other repeat-rich regions within complex genomes.
Unlocking the Secrets Behind Secondary Metabolism: A Review of Aspergillus flavus from Pathogenicity to Functional Genomics

Aspergillus flavus has received a considerable amount of attention due to its ability to produce aflatoxin, a secondary metabolite that is both immunosuppressive and carcinogenic to animals and humans. Research on aflatoxin over the last 40 years has made it one of the best studied fungal secondary metabolites. In spite of the large volume of research in this area, many unanswered questions remain concerning the genetic regulation of aflatoxin production and the molecular signals that intimately associate the synthesis of aflatoxin with specific environmental and nutritional conditions. It is anticipated that the tools now available in the field of genomics will build upon our existing knowledge and provide answers to some of these questions. Complete genome
Exploiting Spatio-Temporal Tradeoffs for Energy-Aware MapReduce in the Cloud

MapReduce is a distributed computing paradigm widely used for building large-scale data processing applications. When used in cloud environments, MapReduce clusters are dynamically created using virtual machines (VMs) and managed by the cloud provider. In this paper, we study the energy efficiency problem for such MapReduce clouds. We describe a unique spatio-temporal tradeoff that includes efficient spatial fitting of VMs on servers to achieve high utilization of machine resources, as well as balanced temporal fitting of servers with VMs having similar runtimes to ensure a server runs at a high utilization throughout its uptime. We propose VM placement algorithms that explicitly incorporate these tradeoffs. Further, we propose techniques that dynamically scale MapReduce clusters to further improve energy consumption while ensuring that jobs meet or improve their expected runtimes. Our algorithms achieve energy savings over existing placement techniques, and an additional optimization technique further achieves savings while simultaneously improving job performance.
Organic nonlinear optical materials: where we have been and where we are going

Nonlinear optical (NLO) materials can be useful for a variety of applications varying from modulation of optical signals facilitated by the electro-optic effect—the effect whereby the refractive index of a material changes in response to an applied electric field—to microfabrication, sensing, imaging, and cancer therapy facilitated by multiphoton absorption, wherein molecules simultaneously absorb two or more photons of light. This short Focus article is a brief personal perspective of some of the key advances in second-order NLO materials and in multiphoton-absorbing materials, and of how and why these advances have led to renewed interest in organic NLO materials.
Structured sublinear compressive sensing via belief propagation

Abstract Compressive sensing (CS) is a sampling technique designed for reducing the complexity of sparse data acquisition. One of the major obstacles for practical deployment of CS techniques is the signal reconstruction time and the high storage cost of random sensing matrices. We propose a new structured compressive sensing scheme, based on codes of graphs, that allows for a joint design of structured sensing matrices and logarithmic-complexity reconstruction algorithms. The compressive sensing matrices can be shown to offer asymptotically optimal performance when used in combination with orthogonal matching pursuit (OMP) methods. For reduced-complexity greedy reconstruction schemes, we propose a new family of list-decoding belief propagation algorithms, as well as reinforced and multiple-basis belief propagation (BP) algorithms. Our simulation results indicate that reinforced BP CS schemes offer very good complexity–performance tradeoffs for very sparse signal vectors.
Tractable Search for Learning Exponential Models of Rankings

We consider the problem of learning the Generalized Mallows (GM) model of [Fligner and Verducci, 1986], which represents a probability distribution over all possible permutations (or rankings) of a given set of objects. The training data consists of a set of permutations. This problem generalizes the well known rank aggregation problem. Maximum Likelihood estimation of the GM model is NP-hard. An exact but inefficient searchbased method was recently proposed for this problem. Here we introduce the first nontrivial heuristic function for this search. We justify it theoretically, and show why it is admissible in practice. We experimentally demonstrate its effectiveness, and show that it is superior to existing techniques for learning the GM model. We also show good performance of a family of faster approximate methods of search.
Chlorosulfolipids: Structure, synthesis, and biological relevance

Chlorosulfolipids have been isolated from freshwater algae and from toxic mussels. They appear to have a structural role in algal membranes and have been implicated in Diarrhetic Shellfish Poisoning. Further fascinating aspects of these compounds include their stereochemically complex polychlorinated structures and the resulting strong conformational biases, and their poorly understood (yet surely compelling) biosynthesis. Discussions of each of these topics and of efforts in structural and stereochemical elucidation and synthesis are the subject of this Highlight.
Enantioselective intramolecular cyclopropanation of N-allylic- and N-homoallylic diazoacetamides catalyzed by chiral dirhodium(II) catalysts

Abstract Diazodecomposition of N-(tert-butyl)-N-(3-buten-1-yl)diazoacetamides catalyzed by dirhodium(II) tetrakis[methyl 2-pyrrolidone-5(S)-carboxylate], Rh2(5S-MEPY)4, and tetrakis[methyl 2-oxazolidinone-4(S)-carboxylate], Rh2(4S-MEOX)4, forms products from intramolecular cyclopropanation in good yields with enantiomeric excesses ranging from 60–90%. Intramolecular cyclopropanation with N, N-diallyldiazoacetamide (72% ee) is competitive with intramolecular [3+2] dipolar cycloaddition.
Flight Dynamics of Unguided Rockets with Free Rolling Wrap Around Tail Fins

This paper presents a study of the dynamics of configurations with free rolling wrap around tail fins. The linearized theory of motion of symmetric missiles is extended to these configurations to define a dynamically equivalent fixed-wrap around fin tail rocket. The effect of asymmetries is introduced by forcing functions at body and tail rate frequencies. Finally Magnus effects and conditions at resonance and resonance lock-in are discussed. Nomenclature CD = drag force coefficient CLα = lift force coefficient slope CNα = normal force coefficient slope CNβ = side force coefficient slope CNq, CN = α� pitch yaw force derivatives CNpq, CN = β� p pitch yaw force derivatives q CN�, CN = q