cssi/SciSciGPT-SciSciNet huggingface dataset:
Maps of Computer Science

We describe a practical approach for visual exploration of research papers. Specifically, we use the titles of papers from the DBLP database to create what we call maps of computer science (MoCS). Words and phrases from the paper titles are the cities in the map, and countries are created based on word and phrase similarity, calculated using co-occurence. With the help of heatmaps, we can visualize the profile of a particular conference or journal over the base map. Similarly, heatmap profiles can be made of individual researchers or groups such as a department. The visualization system also makes it possible to change the data used to generate the base map. For example, a specific journal or conference can be used to generate the base map and then the heatmap overlays can be used to show the evolution of research topics in the field over the years. As before, individual researchers or research group profiles can be visualized using heatmap overlays over a specific journal or conference base map. We outline a modular and extensible system for term extraction using natural language processing techniques, and show the applicability of methods of information retrieval to calculation of term similarity and creation of a topic map. The system is available at mocs.cs.arizona.edu.
Fountain Communication using Concatenated Codes

This paper extends linear-complexity concatenated coding schemes to fountain communication over the discrete-time memoryless channel. Achievable fountain error exponents for one-level and multi-level concatenated fountain codes are derived. Several important properties of the concatenated coding schemes in multi-user fountain communication scenarios are demonstrated.
On an asymmetric correlated flavor factory

There are distinct physics advantages to using asymmetric /spl phi/ factories to test and study CPT and CP violation. However, several beam dynamics issues remain to be addressed, especially for the effects of a high energy linac beam on a low energy target (most likely a storage ring or a recirculator structure). We present a preliminary discussion of collider concepts, especially with regard to the creation of high luminosities. >
A new synthesis of symmetric boraindacene (BODIPY) dyes

BODIPY dyes were synthesized from pyrrole-2-carbaldehyde derivatives in high yields; this constitutes a new approach to this dye framework.
Recycling of homogeneous Pd catalysts using superparamagnetic nanoparticles as novel soluble supports for Suzuki, Heck, and Sonogashira cross-coupling reactions

Recycling of homogeneous catalysts could be achieved by using magnetic nanoparticles and solid-phase beads, but nanoparticle-supported catalysis proceeded much faster than its counterpart on resins.
Testing: principles and practice

Testing is the process of determining whether a task has been correctly carried out. Testing should be performed throughout the software life cycle; it should not be restricted to verification (testing whether a phase has been carried out correctly) and validation (testing whether the completed product satisfies its specifications). The correction of a fault exposed by testing is termed debugging. The goal of testing is to reveal faults. There are two types of testing: execution-based testing and nonexecutionbased testing. It is impossible to execute a specification document; instead, it has to be reviewed carefully. Once executable code has been written it is possible to run test cases, that is, perform execution-based testing. Nevertheless, the existence of code does not preclude nonexecution-based testing because carefully reviewing code will uncover at least as many faults as running test cases. In this survey, the principles and practice of both execution-based and nonexecution-based testing are described.
Civil Rights in International Law: Compliance with Aspects of the "International Bill of Rights"

International law has developed what many might consider a constitutional understanding of individual civil rights that individuals can claim vis-a-vis their own governments. This article discusses the development of aspects of international law relating to civil rights and argues that if this body of law is meaningful, we should see evidence of links between acceptance of international legal obligation and domestic practices. Recognizing that external forms of enforcement of civil rights is unlikely (because doing so is not generally in the interest of potential "enforcers"), I argue that international civil rights treaties will have their greatest effect where stakeholders—local citizens—have the motive and the means to demand treaty compliance. This is most likely to be the case not in stable autocracies, where such demands are likely to be crushed, nor in stable democracies, where the motive to mobilize is attenuated due to rights saturation, but in transitional countries where the expected value of mobilization is maximized. Thus, I test the hypothesis that the International Covenant on Civil and Political Rights is likely to have its greatest positive effects in transitional countries—those that have had some fleeting experience with democratic governance. This proposition is tested quantitatively with indicators for freedom of religious practice and fair trials. The proposition is weakly supported by extremely stringent statistical models that control for the endogeneity of the treaty commitments, country- and year-fixed effects, and other obvious influences on civil rights practices. I conclude that the "International Bill of Rights" has the power to influence the direction of rights practices in fluid political situations, but it cannot magically transform autocracies into liberal guarantors of civil liberties. Still, these effects are important and are the most we can expect from scraps of paper that the international community has been reluctant to enforce.
Chemical Precursors to Zinc Sulfide: ZnS Whisker Synthesis

Abstract : Currently, Chemical Vapor Deposition (CVD) derived zinc sulfide is one of the most widely used infrared optical window materials. Unfortunately, for numerous applications it does not possess optimum mechanical properties. To fabricate infrared transmitting ZnS/ZnS composites requires the development of high aspect ratio, micron sized ZnS whiskers. Although larger ZnS single crystals and whiskers have been made by a variety of high temperature route, alternative routes have been sought for greater ZnS whisker morphology control. Low temperature organometallic routes are attractive for this purpose. The precursor compound used in this study is the known pentameric species (EtZn(SBut))5. One of the most successful routes involves the reaction of (EtZn(SBU superscript t))5 with hydrogen sulfide at ambient or sub-ambient temperature to yield a precipitate which is subsequently heated under flowing H2S at 500 C to yield a mixture of sub-micron particles and single-crystal ZnS whiskers. Transmission electron micrographs of the (EtZn(SBU superscript t))5 products indicate that the ZnS morphology is critically dependent upon the rate of H2S reaction. Corresponding x-ray/electron diffraction, electron microscopy, elemental analysis, NMR and infrared spectroscopies have been conducted. A summary of the chemical methods, product characterization results, and proposed synthesis mechanisms will be presented. Keywords: Ethyl radicals.
Linear geometric number patterns: Middle school students’ strategies

In this study, 23 seventh- and eighth-grade students were interviewed as they solved problems related to four linear geometric number patterns involving perimeter and area. In particular, they developed symbolic expressions for the pattern relationships and assessed the validity of given expressions. The strategies indicated in the responses suggest four levels of thinking about linear geometric number patterns: (1) concrete modelling and counting, (2) inappropriate use of proportion, (3) focus on recursive relationships, and (4) analysis of the functional relation between a perimeter or area and the shape number.
Atmospheric density at 169 km from accelerometer measurements and orbital decay of a low altitude satellite

Abstract Atmospheric densities at 169 km have been obtained for the period 19 August–3 September 1970 from the measurements of an accelerometer on a low altitude satellite and from the orbital decay of the same satellite. Three different sets of local time and latitude conditions were provided by the data; two from the accelerometer measurements, before and after perigee, and one at perigee, from the orbital decay data. Under the generally quiet magnetic activity conditions that prevailed during the data-taking period, the short term density fluctuations were found to be poorly correlated with the small Kp variations. However, on the greater time scale of a day, a definite relationship was found between the daily average density and the daily geomagnetic index Ap. Further, the increase in the density corresponding to Ap was largest at the highest latitude. The high latitude accelerometer data exhibited a quasi-daily periodicity, with maximum densities occurring when the satellite was within the dayside cusp. This effect also appeared to depend on the degree of auroral electrojet activity as defined by the AE index. Comparisons of the data with the Jacchia−70 and −71 models indicated that these models may give density values which are too small for the conditions and time period corresponding to the data.
Open Systems: a process for achieving affordability

A major factor that will drive the definition and design of future avionics systems is affordability. Affordability is being addressed on numerous fronts such as hardware re-use, software re-use, COTS leveraging, and reduced cycle times. Each of these thrusts provide potential cost saving along with unique challenges. What is needed is a process that integrates these initiatives while ensuring the overall system objectives are achieved. An Open Systems-based process is key to integrating these initiatives and balancing affordability and system performance goals. Although Open Systems are being widely recognized as a key to affordability, most interpret Open Systems as a set of system attributes that need to be achieved. There are numerous claims of vendors saying they have an Open Systems architecture; or how their system will evolve to an Open Systems architecture. This emphasis is not on increasing affordability, but on attaching a politically-correct label to their product. In this paper, we focus on the Open Systems process as the key to affordability. An Open Systems process is based on Open Systems principles. This paper discusses the Open Systems principles and process in detail and shows how this process integrates numerous affordability initiatives.
Stochastic approach to the molecular counting problem in superresolution microscopy

Superresolution imaging methods—now widely used to characterize biological structures below the diffraction limit—are poised to reveal in quantitative detail the stoichiometry of protein complexes in living cells. In practice, the photophysical properties of the fluorophores used as tags in superresolution methods have posed a severe theoretical challenge toward achieving this goal. Here we develop a stochastic approach to enumerate fluorophores in a diffraction-limited area measured by superresolution microscopy. The method is a generalization of aggregated Markov methods developed in the ion channel literature for studying gating dynamics. We show that the method accurately and precisely enumerates fluorophores in simulated data while simultaneously determining the kinetic rates that govern the stochastic photophysics of the fluorophores to improve the prediction’s accuracy. This stochastic method overcomes several critical limitations of temporal thresholding methods.
Distributed generation of weighted random patterns

This paper describes the design details, operation, cost, and performance of a distributed weighted pattern test approach at the chip level. The traditional LSSD SRLs are being replaced by WRP SRLs designed specifically to facilitate a weighted random pattern (WRP) test. A two-bit code is transmitted to each WRP SRL to determine its specific weight. The WRP test is then divided into groups, where each group is activated with a different set of weights. The weights are dynamically adjusted during the course of the test to "go after" the remaining untested faults. The cost and performance of this design system are explored on ten pilot chips. Results of this experiment are provided in the paper.
Negative pressure characteristics of an evaporating meniscus at nanoscale

This study aims at understanding the characteristics of negative liquid pressures at the nanoscale using molecular dynamics simulation. A nano-meniscus is formed by placing liquid argon on a platinum wall between two nano-channels filled with the same liquid. Evaporation is simulated in the meniscus by increasing the temperature of the platinum wall for two different cases. Non-evaporating films are obtained at the center of the meniscus. The liquid film in the non-evaporating and adjacent regions is found to be under high absolute negative pressures. Cavitation cannot occur in these regions as the capillary height is smaller than the critical cavitation radius. Factors which determine the critical film thickness for rupture are discussed. Thus, high negative liquid pressures can be stable at the nanoscale, and utilized to create passive pumping devices as well as significantly enhance heat transfer rates.
K-Shell Ionization by Low-Velocity Ions

K-shell x-ray production measurements are reported for protons, deuterons and alpha particles incident on thin foils of copper, niobium, silver and antimony. In the velocity range of the experiments, which correspond to 100-600 keV/u, the energy of ionization was as large as 10% of the bombarding energy. The inferred dependence of the excitation process on the projectile mass, atomic number and energy is compared with theoretical estimates of a low-velocity ionization threshold, the binding effect and the Coulomb-deflection effect. Precision of measurement is not great enough to discern unambiguously the threshold effect, but the binding and Coulomb-deflection effects are clearly distingui shed.
Minimizing energy consumption for cooperative network and diversity coded sensor networks

In this paper, we present an approach to minimize the energy consumption of multihop wireless packet networks, while achieving the required level of reliability. We consider networks that use Cooperative Network Coding (CNC), which is a synergistic combination of Cooperative Communications and Network Coding. Our approach is to optimize and balance the use of forward error control, error detection, and retransmissions at the packet level for these networks. Additionally, we introduce Cooperative Diversity Coding (CDC), which is a novel means to code the information packets, with the aim of minimizing the energy consumed for coding operations. The performance of CDC is similar to CNC in terms of the probability of successful reception at the destination and expected number of correctly received information packets at the destination. However, CDC requires less energy at the source node because of its implementation simplicity. Achieving minimal energy consumption, with the required level of reliability is critical for the optimum functioning of many wireless sensor and body area networks. For representative applications, the optimized CDC or CNC network achieves ≥ 25% energy savings compared to the baseline CNC scheme.
Where do innovations come from? Transformations in the US economy, 1970–2006

In the 1970s, there was a lively debate on both sides of the Atlantic about deep discontinuities in the development of advanced market societies. Much of this debate centered on the idea of postindustrial society-emphasizing a shift from goods to services and the rise of science-based production. A wide range of scholars argued that U.S. society, in particular, required significant institutional changes to take advantage of these new productive possibilities (Bell 1973; Brick 2006; Touraine 1971). Parallel arguments for discontinuity were made by theorists of fifty-to sixty-year economic long waves (Mandel 1980) and by contributors to regulation theory, who also argued that capitalist societies required new regulatory structures (Aglietta 1979).1 These arguments continued into the next decade, as reflected in the wide interest generated by Piore and Sabel’s argument in the Second Industrial Divide (1984) for a fundamental shift in the organization of production.
A mean value theorem for the Diophantine equation axy − x − y = n

We prove an asymptotic formula for the average number of solutions to the Diophantine equation axy−x−y=n in which a is fixed and n varies.
Evasion paths in mobile sensor networks

Suppose that ball-shaped sensors wander in a bounded domain. A sensor does not know its location but does know when it overlaps a nearby sensor. We say that an evasion path exists in this sensor network if a moving intruder can avoid detection. In 'Coordinate-free coverage in sensor networks with controlled boundaries via homology', Vin de Silva and Robert Ghrist give a necessary condition, depending only on the time-varying connectivity data of the sensors, for an evasion path to exist. Using zigzag persistent homology, we provide an equivalent condition that moreover can be computed in a streaming fashion. However, no method with time-varying connectivity data as input can give necessary and sufficient conditions for the existence of an evasion path. Indeed, we show that the existence of an evasion path depends not only on the fibrewise homotopy type of the region covered by sensors but also on its embedding in spacetime. For planar sensors that also measure weak rotation and distance information, we provide necessary and sufficient conditions for the existence of an evasion path.
Relativistic effects and the chemistry of gold

In atoms of high nuclear charge (Z), as a consequence of a relativistic effect, the s electrons of an atom become more bound and their orbitals smaller than if this effect were absent. Simultaneously, the d (and f ) electrons are less bound because of this effect, which scales roughly as Z2. Gold exhibits a large relativistic effect. This accounts for gold being more resistant to oxidation than silver. It also accounts for higher oxidation states being more accessible in gold than in silver. These effects are illustrated by some fluorine chemistry of gold and silver.
Group Dynamics of Elementary Particles

It is proposed that particle interactions can be described by means of simple group operations in non-compact Lie groups. Prescriptions for the structure of these group operations are formulated which are motivated by the study of simple models, in particular of the dynamics of the hydrogen atom. If they are fulfilled we call the structure “group dynamics”. Neglecting at first internal symmetries, a few simple models are investigated in which group dynamics is possible. The group O(3,1) turns out to describe the coupling of pseudoscalar mesons, O(4,2) that of photons to baryons quite well: The pionic decay rates of baryon resonances up to spin 19/2 and the electromagnetic form factors of the nucleons are predicted in good agreement with experiment. The internal symmetry SU(3) is included in the O(3.1) model of the pionic coupling in the simplest way, by assuming O(3,1) × SU(3) to be the dynamical group. This gives rise to a minimal symmetry breaking of the amplitudes and relates it to the mass differences in SU(3) multiplets: The amplitude consists of a product of a SU(3) Clebsch Gordan coefficient and a universal function of the velocity of the final baryon. The way the particle masses enter the decay rates is uniquely prescribed in this approach. The agreement with experiment is excellent. Finally, the connection of this purely algebraic approach with related ideas, like the use of infinite component wave equations, is discussed.
Economic Freedom and Recidivism: Evidence from US States

This paper provides an exploratory analysis into factors contributing to differences across states in recidivism rates. We provide the first such examination that incorporates differences in economic freedom. Using a panel data set from 1998 to 2010, we find that higher levels of economic freedom within a state are associated with lower recidivism rates within that state. A one percent increase in state economic freedom is associated with a 0.47 % decrease in parolee recidivism. The relationship is stronger and more statistically significant for labor market freedom, with a one percent increase in labor market freedom being associated with a 0.67 % decline in recidivism.
Remanufacturing: Impacts of Sacrificial Cylinder Liners

Remanufacturing offers the potential for simultaneously recovering the economic value of manufactured components and improving the environment. Some design features make remanufacturing less expensive and/or increase the proportion of components that can be remanufactured. For example, sacrificial components can be used to protect key parts from wear. However, trade-offs are sometimes involved, and product designers need tools to support design for remanufacturing. This paper presents models for estimating the costs and environmental impacts of employing sacrificial components (cylinder liners) in engine blocks. These models are incorporated into a spreadsheet-based design decision tool. Three illustrative examples demonstrate that (1) remanufacturing lowers overall costs when two life cycles are considered, (2) sacrificial cylinder liners should be employed for small (2 L) engines, and their superiority increases with multiple remanufacturing cycles, and (3) for large engines (5.3 L) using cylinder liners is equally preferred to not using them, with respect to both overall cost and environmental impacts.
sn-Beta zeolites with borate salts catalyse the epimerization of carbohydrates via an intramolecular carbon shift

Carbohydrate epimerization is an essential technology for the widespread production of rare sugars. In contrast to other enzymes, most epimerases are only active on sugars substituted with phosphate or nucleotide groups, thus drastically restricting their use. Here we show that Sn-Beta zeolite in the presence of sodium tetraborate catalyses the selective epimerization of aldoses in aqueous media. Specifically, a 5 wt% aldose (for example, glucose, xylose or arabinose) solution with a 4:1 aldose:sodium tetraborate molar ratio reacted with catalytic amounts of Sn-Beta yields near-equilibrium epimerization product distributions. The reaction proceeds by way of a 1,2 carbon shift wherein the bond between C-2 and C-3 is cleaved and a new bond between C-1 and C-3 is formed, with C-1 moving to the C-2 position with an inverted configuration. This work provides a general method of performing carbohydrate epimerizations that surmounts the main disadvantages of current enzymatic and inorganic processes.
Signaling Quality via Queues

We consider an M/M/1 queueing system with impatient consumers who observe the length of the queue before deciding whether to buy the product. The product may have high or low quality, and consumers are heterogeneously informed. The firm chooses a slow or (at a cost) a fast service rate. In equilibrium, informed consumers join the queue if it is below a threshold. The threshold varies with the quality of the good, so an uninformed consumer updates her belief about quality on observing the length of the queue. The strategy of an uninformed consumer has a “hole”: she joins the queue at lengths both below and above the hole, but not at the hole itself. We show that if the prior probability the product has high quality and the proportion of informed consumers are both low, a high-quality firm may select a slower service rate than a low-quality firm. The queue can therefore be a valuable signaling device for a high-quality firm. Strikingly, in some scenarios, the high-quality firm may choose the slow service rate even if the technological cost of speeding up is zero. This paper was accepted by Assaf Zeevi, stochastic models and simulation.
An N-Heterocyclic Carbene/Lewis Acid Strategy for the Stereoselective Synthesis of Spirooxindole Lactones

A cooperative catalysis approach for the enantioselective formal [3+2] addition of α,β-unsaturated aldehydes to isatins has been developed. The N-heterocyclic carbene (NHC)-catalyzed homoenolate annulations of β-aryl enals require the addition of lithium chloride for high levels of enantioselectivity. This NHC-catalyzed annulation provides efficient access to the 3-hydroxy indole skeleton and has been applied to the first eantioselective total synthesis of maremycin B.
Balancing IT with the Human Touch: Optimal Investment in IT-Based Customer Service

To cut costs, companies have chosen to deliver a variety of service offerings online. However, the digital systems providing such services (e-service) have always been complemented with or supported by human-based service (h-service). Whereas h-service has total costs that increase with the demand for services, e-service mainly requires a fixed investment upfront, which can be amortized over the totality of customers served. Considering the different nature of the costs of h-service and e-service and the heterogeneity of customer preferences for services, we derive the optimal mix of h-service and e-service for a service-providing company vis-a-vis its competitor. Our theoretical analysis finds the subgame-perfect Nash equilibria that determines the optimal positions in a duopoly setting. We further study the competitive dynamics of the system to examine how firms stay on the equilibrium paths. Using simulation, we investigate the effects of starting positions, small adjustments in h-service and/or e-service, and monotonic expansions of e-service on the final positioning and profits of the firms. Our results demonstrate that when firms follow a local best-reply strategy, they may end up in a position of low profitability, and when only monotonic expansions of e-service are allowed, both firms may end up overinvesting in e-service.
Online Structured Prediction via Coactive Learning

We propose Coactive Learning as a model of interaction between a learning system and a human user, where both have the common goal of providing results of maximum utility to the user. At each step, the system (e.g. search engine) receives a context (e.g. query) and predicts an object (e.g. ranking). The user responds by correcting the system if necessary, providing a slightly improved - but not necessarily optimal - object as feedback. We argue that such feedback can often be inferred from observable user behavior, for example, from clicks in web-search. Evaluating predictions by their cardinal utility to the user, we propose efficient learning algorithms that have O(1/√T) average regret, even though the learning algorithm never observes cardinal utility values as in conventional online learning. We demonstrate the applicability of our model and learning algorithms on a movie recommendation task, as well as ranking for web-search.
Asymptotic improvement of the Gilbert-Varshamov bound on the size of binary codes

Given positive integers n and d, let A/sub 2/(n,d) denote the maximum size of a binary code of length n and minimum distance d. The well-known Gilbert-Varshamov bound asserts that A/sub 2/(n,d)/spl ges/2/sup n//V(n,d-l), where V(n,d) = /spl sigma//sub i=0//sup d/(/sub i//sup n/) is the volume of a Hamming sphere of radius d. We show that, in fact, there exists a positive constant c such that A/sub 2/(n, d)/spl ges/c2/sup n//V(n,d-1)log/sub 2/V(n, d-1) whenever d/n/spl les/0.499. The result follows by recasting the Gilbert-Varshamov bound into a graph-theoretic framework and using the fact that the corresponding graph is locally sparse. Generalizations and extensions of this result are briefly discussed.
Technological challenges to x-ray FELs

There is strong interest in the development of X-ray Free Electron Lasers (X-ray FELs). The interest is driven by the scientific opportunities provided by intense, coherent X-rays. An X-ray FEL has all the characteristics of a fourth-generation source: brightness several orders of magnitude greater than presently achieved in third-generation sources, full transverse coherence, and sub-picosecond long pulses. The SLAC and DESY laboratories have presented detailed design studies for X-ray FEL user-facilities around the 0.1 nm wavelength regime (LCLS at SLAC, TESLA X-ray FEL at DESY). Both laboratories are engaged in proof-of-principle experiments at longer wavelengths (TTF FEL Phase I at 71 nm, VISA at 600–800 nm) with results expected in 1999. The technologies needed to achieve the proposed performances are those of bright electron sources, of acceleration systems capable of preserving the brightness of the source, and of undulators capable of meeting the magnetic and mechanical tolerances that are required for operation in the SASE mode. This paper discusses the technological challenges presented by the X-ray FEL projects.
Political Aftershocks: The Impact of Earthquakes on Intrastate Conflict

Although many scholars, policy makers, and relief organizations suggest that natural disasters bring groups together and dampen conflicts, earthquakes can actually stimulate intrastate conflict by producing scarcities in basic resources, particularly in developing countries where the competition for scarce resources is most intense. Capitalizing on a natural experiment design, this study examines the impact of earthquakes on intrastate conflict through a statistical analysis of 185 countries over the period from 1975 to 2002. The analysis indicates that earthquakes not only increase the likelihood of conflict, but that their effects are greater for higher magnitude earthquakes striking more densely populated areas of countries with lower gross domestic products as well as preexisting conflicts. These results suggest that disaster recovery efforts must pay greater attention to the conflict-producing potential of earthquakes and undertake certain measures, including strengthening security procedures, to pre...
Ultrashort intense-field optical vortices produced with laser-etched mirrors.

We introduce a simple and practical method to create ultrashort intense optical vortices for applications involving high-intensity lasers. Our method utilizes femtosecond laser pulses to laser etch grating lines into laser-quality gold mirrors. These grating lines holographically encode an optical vortex. We derive mathematical equations for each individual grating line to be etched, for any desired (integer) topological charge. We investigate the smoothness of the etched grooves. We show that they are smooth enough to produce optical vortices with an intensity that is only a few percent lower than in the ideal case. We demonstrate that the etched gratings can be used in a folded version of our 2f-2f setup [Opt. Express 19, 7599 (2005)] to compensate angular dispersion. Finally, we show that the etched gratings withstand intensities of up to 1012 W/cm2.
Spacecraft tracking with the SKA

Abstract The possibility of using the SKA for occasional support of scientific space missions should be considered, along with all other science goals, in the design of the array. The benefits of higher data rates from distant spacecraft during high priority, short duration mission phases can be dramatic, while the technical requirements on the SKA to allow this capability are very few. The most fundamental requirement is coverage of the primary downlink frequencies for deep space missions. Additional benefits can result from real-time high precision angular position measurements of spacecraft. Such measurements allow spacecraft navigation with reduced errors and reduced risk, but require at least some long (thousands of km) baselines.
Cyclic Sieving for Longest Reduced Words in the Hyperoctahedral Group

We show that the set $R(w_0)$ of reduced expressions for the longest element in the hyperoctahedral group exhibits the cyclic sieving phenomenon. More specifically, $R(w_0)$ possesses a natural cyclic action given by moving the first letter of a word to the end, and we show that the orbit structure of this action is encoded by the generating function for the major index on $R(w_0)$.
Transient growth in driven contact lines

The problem of transient growth in the distortion of driven contact lines has recently sparked a controversy as to whether this mechanism can provide an alternative route to pattern formation in the absence of linear instability. To resolve the disagreement between previous studies we conduct a generalized linear stability analysis of different lubrication models of gravity-driven spreading and compare our results with those based on direct numerical simulations. We find that linear and non-linear theory are in reasonable qualitative agreement and show that the quantitative discrepancies in the predicted transient growth are caused by the differences in: (1) the choice of initial disturbances and (2) the definition of the maximal transient amplification used in different studies. We further show by comparing the predictions of the precursor and the slip model that the latter substantially underestimates transient growth by neglecting the disturbances in the slip parameter.
Stochastic Heat Transfer in Fins and Transient Cooling Using Polynomial Chaos and Wick Products

Stochastic heat transfer problems are often solved using a perturbation approach that yields estimates of mean values and standard deviations for properties and boundary conditions that are random variables. Methods based on polynomial chaos and Wick products can be used when the randomness is a random field or white noise to describe specific realizations and to determine the statistics of the response. Polynomial chaos is best suited for problems in which the properties are strongly correlated, while the Wick product approach is most effective for variables containing white noise components. A transient lumped capacitance cooling problem and a one-dimensional fin are analyzed by both methods to demonstrate their usefulness.
Quantum Diffusion of Planck Mass and the Evolution of the Universe

The inflationary paradigm has two main features that makes it very attractive. First, its classical evolution as an exponential expansion of the universe, that solves simultaneously many of the long standing problems of the standard cosmological model, like the flatness, horizon and homogeneity problems. On the other hand, its quantum evolution, which provides a simple means of generating the required density perturbations in the homogeneous background necessary for galaxy formation [1]. However, the same mechanism that generates those ripples in the metric is responsible, at scales much beyond our observable universe, for a very inhomogeneous large scale structure of the universe [2]. We will be mainly interested in the description of such a large scale structure. The main ingredients that play a role in the inflationary scenario are on the one hand particle physics, through the description of the effective potential for the inflaton, and on the other hand gravitational physics, that describes the cosmological expansion of the universe. The latter could be studied in the context of general relativity or by alternative gravitational theories like Brans-Dicke. Apart from the general laws of motion, one requires a set of initial conditions for the universe. Early models of inflation postponed the issue by assuming that the universe started in a very hot state that supercooled in a metastable vacuum, which then decayed to the true vacuum [1]. But in fact, the only reasonable approach to the initial value problem is the use of quantum cosmology since the most natural initial conditions for inflation are at Planck scale, where quantum fluctuations of the space-time metric become important. This was particularly emphasized in the chaotic inflation scenario [3], which opened the possibility of arbitrary initial conditions for the inflaton field in arbitrary effective potentials. A question remained, what is the probability distribution for those inflationary domains that started their evolution close to the Planck boundary? Quantum cosmology proposed an answer, based on the path integral formulation of quantum gravity, which is still under debate [2]. In the meanwhile, the so called stochastic approach to inflation was developed [4, 5]. This formalism takes into account the Brownian motion of the inflaton field under the effect of its own quantum fluctuations and is described with the help of ordinary diffusion equations. One of the most fascinating features of inflation is the self-reproduction of
Prioritized LT codes

It is common in data transmissions that some information is more important than others. This is especially true in space communications where mission critical information or science data are high priority. In this work, we propose a simple yet constructive scheme to send high priority data reliably and efficiently using Luby transform (LT) codes. The new proposed scheme modifies the conventional LT encoder to send high priority data as a degree 1 and 2 so that high priority data can be quickly resolved and very likely recovered before a decoder stops. Preliminary results show that a carefully designed degree distribution of high priority data increases the likelihood of receiving high priority information while having negligible performance impact on data with lower priority. The performance of the proposed scheme is evaluated and compared with the conventional LT approach with the same parameters under a range of erasure error rates.
Reverse Mechanism Design

Optimal mechanisms for agents with multi-dimensional preferences are generally complex. This complexity makes them challenging to solve for and impractical to run. In a typical mechanism design approach, a model is posited and then the optimal mechanism is designed for the model. Successful mechanism design gives mechanisms that one could at least imagine running. By this measure, multi-dimensional mechanism design has had only limited success. In this paper we take the opposite approach, which we term reverse mechanism design. We start by hypothesizing the optimality of a particular form of mechanism that is simple and reasonable to run, then we solve for sufficient conditions for the mechanism to be optimal (among all mechanisms). This paper has two main contributions. The first is in codifying the method of virtual values from single-dimensional auction theory and extending it to agents with multidimensional preferences. The second is in applying this method to two paradigmatic classes of multi-dimensional preferences. The first class is unit-demand preferences (e.g., a homebuyer who wishes to buy at most one house); for this class we give sufficient conditions under which posting a uniform price for each item is optimal. This result generalizes one of Alaei et al. [2013] for a consumer with values uniform on interval [0; 1], and contrasts with an example of Thanassoulis [2004] for a consumer with values uniform on interval [5; 6] where uniform pricing is not optimal. The second class is additive preferences, for this class we give sufficient conditions under which posting a price for the grand bundle is optimal. This result generalizes a recent result of Hart and Nisan [2012] and relates to work of Armstrong [1999]. Similarly to an approach of Alaei et al. [2013], these results for single-agent pricing problems can be generalized naturally to multi-agent auction problems.
Network coding-based protection strategies against a single link failure in optical networks

In this paper we develop network protection strategies against a single link failure in optical networks. The motivation behind this work is the fact that %70 of all available links in an optical network suffers from a single link failure. In the proposed protection strategies, denoted NPS-I and NPS-II, we deploy network coding and reduced capacity on the working paths to provide a backup protection path that will carry encoded data from all sources. In addition, we provide implementation aspects and how to deploy the proposed strategies in case of an optical network with n disjoint working paths.
Synchrotron Constraints on a Hybrid Cosmic-Ray and Thermally-Driven Galactic Wind

Cosmic rays and magnetic fields can substantially impact the launching of large-scale galactic winds. Many researchers have investigated the role of cosmic rays; our group previously showed that a cosmic-ray and thermally driven wind could explain soft X-ray emission toward the center of the Galaxy. In this paper, we calculate the synchrotron emission from our original wind model and compare it to observations; the synchrotron data show that earlier assumptions about the launching conditions of the wind must be changed: we are required to improve that earlier model by restricting the launching region to the domain of the inner Molecular Ring, and by decreasing the magnetic field strength from the previously assumed maximum strength. With these physically motivated modifications, we find that a wind model can fit both the radio synchrotron and the X-ray emission, although that model is required to have a higher gas pressure and density than the previous model in order to reproduce the observed X-ray emission within the smaller footprint. The drop in magnetic field also decreases the effect of cosmic-ray heating, requiring a higher temperature at the base of the wind than the previous model.
Low cohomogeneity and polar actions on exceptional compact Lie groups

We study isometric Lie group actions on the compact exceptional groups E6, E7, E8, F4 and G2 endowed with a bi-invariant metric. We classify polar actions on these groups, in particular, we show that all polar actions are hyperpolar. We determine all isometric actions of cohomogeneity less than three on E6, E7, F4 and all isometric actions of cohomogeneity less than 20 on E8. Moreover, we determine the principal isotropy algebras for all isometric actions on G2.
Preparation of N-hydroxysuccinimido esters via palladium-catalyzed carbonylation of aryl triflates and halides ☆

N-Hydroxysuccinimido esters of aromatic carboxylic acids (a.k.a. active esters) can be made using a potentially general, one-step procedure via Pd-catalyzed carbonylation of an aryl triflate or aryl iodide with CO and N-hydroxysuccinimide. Excellent yields (up to 94%) were observed when the reaction was done in DMSO at 70°C and 1 atmosphere of CO pressure.
Early Capacity Testing of an Enterprise Service Bus

An enterprise service-oriented architecture is typically done with a messaging infrastructure called an Enterprise Service Bus (ESB). An ESB is a bus which delivers messages from service requesters to service providers. Since it sits between the service requesters and providers, it is not appropriate to use any of the existing capacity planning methodologies for servers, such as modeling, to estimate the capacity of an ESB. There are programs that run on an ESB called mediation modules. Their functionalities vary and depend on how people use the ESB. This creates difficulties for capacity planning and performance evaluation. This article proposes a capacity planning methodology and performance evaluation techniques for ESBs, to be used in the early stages of the system development life cycle. The authors actually run the ESB on a real machine while providing a pseudo-environment around it. In order to simplify setting up the environment they provide ultra-light service requestors and service providers for the ESB under test. The authors show that the proposed mock environment can be set up with practical hardware resources available at the time of hardware resource assessment. Their experimental results showed that the testing results with our mock environment correspond well with the results in the real environment.
Special Report: Biomedical Imaging Research Opportunities Workshop IV. A Summary of Findings and Recommendations

The fourth Biomedical Imaging Research Opportunities Workshop (BIROW IV) was held in February, 2006 in Bethesda, Maryland. The workshop explored four promising areas of imaging research: Imaging of rodent models; Imaging in drug development; Imaging of chronic metabolic disease – diabetes; and Image-guided intervention in the 4th dimension – time. These explorations uncovered multiple research opportunities that have the potential of enhancing the discovery of new knowledge, providing more efficient pathways for drug development, yielding improvements in the management of chronic metabolic diseases such as diabetes mellitus, and guiding medical interventions such as surgery, radiation oncology, and ablation therapy. Research challenges were identified in each of these areas of opportunity that must be resolved through scientific exploration and technology development. The meeting concluded with the observation that research in biomedical imaging offers the potential of improving patient care in many ways, and the promise of exciting and rewarding careers to young research aspirants.
A reciprocity map and the two-variable $p$-adic $L$-function

For primes p 5, we propose a conjecture that relates the values of cup products in the Galois cohomology of the maximal unramied outside p extension of a cyclotomic eld on cyclotomic p-units to the values of p-adic L-functions of cuspidal eigenforms that satisfy mod p congruences with Eisenstein series. Passing up the cyclotomic and Hida towers, we construct an isomorphism of certain spaces that allows us to compare the value of a reciprocity map on a particular norm compatible system of p-units to what is essentially the two-variable p-adic L-function of Mazur and Kitagawa.
Examining Megachurch Growth: Free Riding, Fit, and Faith

Megachurches are thriving in religious markets at a time when Americans are asserting their ability as consumers of religious products to engage in religious switching. The apparent success of megachurches, which often provide a low cost and low commitment path by which religious refugees may join the church, seems to challenge Iannocconne’s theory that high commitment churches will thrive while low commitment churches will atrophy. This paper employs a signaling model to illustrate the strategy and organizational forms megachurches employ to indicate a match between what the church produces and the religious refugee wishes to consume in an effort to increase their membership. The model illustrates that megachurches expect little in regard to financial or time commitment of new attendees. However, once the attendees perceive a good fit with the church, the megachurch increases its expectation of commitment. Data from the FACT2000 survey provide evidence in support of the model’s predictions.
CpG Island Structure and Trithorax/Polycomb Chromatin Domains in Human Cells

TrxG and PcG complexes play key roles in the epigenetic regulation of development through H3K4me3 and H3K27me3 modification at specific sites throughout the human genome, but how these sites are selected is poorly understood. We find that in pluripotent cells, clustered CpG-islands at genes predict occupancy of H3K4me3 and H3K27me3, and these "bivalent" chromatin domains precisely span the boundaries of CpG-island clusters. These relationships are specific to pluripotent stem cells and are not retained at H3K4me3 and H3K27me3 sites unique to differentiated cells. We show that putative transcripts from clustered CpG-islands predict stem-loop structures characteristic of those bound by PcG complexes, consistent with the possibility that RNA facilitates PcG recruitment or maintenance at these sites. These studies suggest that CpG-island structure plays a fundamental role in establishing developmentally important chromatin structures in the pluripotent genome, and a subordinate role in establishing TrxG/PcG chromatin structure at sites unique to differentiated cells.