cssi/SciSciGPT-SciSciNet huggingface dataset:
Statistical Analysis of Mesoscale Rainfall: Dependence of a Random Cascade Generator on Large-Scale Forcing

Abstract Under the theory of independent and identically distributed random cascades, the probability distribution of the cascade generator determines the spatial and the ensemble properties of spatial rainfall. Three sets of radar-derived rainfall data in space and time are analyzed to estimate the probability distribution of the generator. A detailed comparison between instantaneous scans of spatial rainfall and simulated cascades using the scaling properties of the marginal moments is carried out. This comparison highlights important similarities and differences between the data and the random cascade theory. Differences are quantified and measured for the three datasets. Evidence is presented to show that the scaling properties of the rainfall can be captured to the first order by a random cascade with a single parameter. The dependence of this parameter on forcing by the large-scale meteorological conditions, as measured by the large-scale spatial average rain rate, is investigated for these three da...
An almost sure invariance principle for random walks in a space-time random environment

We consider a discrete time random walk in a space-time i.i.d. random environ- ment. We use a martingale approach to show that the walk is diffusive in almost every fixed environment. We improve on existing results by proving an invariance principle and con- sidering environments with an L 2 averaged drift. We also state an a.s. invariance principle for random walks in general random environments whose hypothesis requires a subdiffusive bound on the variance of the quenched mean, under an ergodic invariant measure for the environment chain.
MicroRNA-23b Functions as a Tumor Suppressor by Regulating Zeb1 in Bladder Cancer

MicroRNAs (miRNAs) are small, non-coding RNAs that regulate gene expression by targeted repression of transcription and translation. In this study we show that miRNA-23b (miR-23b) acts as a tumor suppressor in bladder cancer. Quantitative real-time PCR analysis showed that miR-23b is significantly down-regulated in bladder cancer cell lines and tumor tissues compared to non-malignant cells and normal tissue samples. We also demonstrate that miR-23b expression has a potential to be diagnostic and prognostic biomarker in bladder cancer. High miR-23b expression is positively correlated with higher overall survival of bladder cancer patients as revealed by Kaplan-Meier analysis. ROC analysis showed that miR-23b expression can distinguish between normal and bladder cancer tissues. Further we elucidated the biological significance of miR-23b in bladder cancer. Over-expression of miR-23b in bladder cancer cells inhibited cell proliferation and impaired colony formation. Fluorescence activated cell sorting (FACS) analysis revealed that re-expression of miR-23b in bladder cancer cells induced G0/G1 cell cycle arrest and apoptosis while inhibiting cell migration and invasion. Luciferase reporter assays demonstrated that Zeb1, a crucial regulator of epithelial-to-mesenchymal transition (EMT), is a direct target of miR-23b in bladder cancer. These results show that loss of miR-23b confers a proliferative advantage and promotes bladder cancer cell migration and invasion. Furthermore, re-expression of miR-23b may be a beneficial therapeutic strategy for the treatment of human bladder cancer.
Flow visualization during multiple-axis motions using a wind-driven manipulator

This article explores the problem of capturing vortex flow interactions that occur during coupled-axis maneuvers at finite rates. A wind-driven dynamic manipulator (WDM) has been developed to perform simultaneous motions repetitively about two degrees of freedom under open-loop or feedback control in a low-speed wind tunnel. The concept of the WDM is examined and support interference is shown to be small compared to that in conventional approaches to maneuver simulation. Vortex flow interactions occurring near the vertical fins of a 1/32-scale fighter configuration during pitch, yaw, and coupled pitch-yaw motions are explored using quantitative laser sheet videography. Large asymmetry and complex interactions are observed in the flowfield. Vortices generated by the forebody, wing leading edge, wingtip, and vertical fins are seen to interact during the coupled pitch-yaw maneuver. Maneuvers are limited to reduced frequencies below 0.036, based on wingspan. Vortex locations are seen to be accurately reproducible and to be independent of rate as expected in this regime. Even at such low rates, several transient interaction phenomena are observed, involving vortices and control surfaces. Quantification of such phenomena is demonstrated.
Effective potential for the massless KPZ equation

Abstract In previous work we have developed a general method for casting a classical field theory subject to Gaussian noise (that is, a stochastic partial differential equation (SPDE)) into a functional integral formalism that exhibits many of the properties more commonly associated with quantum field theories (QFTs). In particular, we demonstrated how to derive the one-loop effective potential. In this paper we apply the formalism to a specific field theory of considerable interest, the massless KPZ equation (massless noisy Burgers equation), and analyze its behavior in the ultraviolet (short-distance) regime. When this field theory is subject to white noise we can calculate the one-loop effective potential and show that it is one-loop ultraviolet renormalizable in 1, 2, and 3 space dimensions, and fails to be ultraviolet renormalizable in higher dimensions. We show that the one-loop effective potential for the massless KPZ equation is closely related to that for λφ 4 QFT . In particular, we prove that the massless KPZ equation exhibits one-loop dynamical symmetry breaking (via an analog of the Coleman–Weinberg mechanism) in 1 and 2 space dimensions, and that this behavior does not persist in 3 space dimensions.
Content analysis of online co-design community interactions: A case study of crowd-sourced Threadless

Abstract The purpose of this research is to understand the nature, size, and lifecycle of online co-design community interactions through a focused case study of a real business with an aim to provide actionable strategies for co-design service innovation and advancement, and help to forecast future trends in crowd-sourced co-design. Crowd-sourced, socially-empowered design environments not only reduce the cost of design sourcing and production, but also address individual user's needs for experience sharing, entertainment, and relationship building in the virtual world. Although a great body of research has been established in both co-design (Hoftijzer, J., 2009; Piller, 2008; Relph-Knight, L., 2008; Piller et al, 2005, 2004; Ives, and Piccoli, 2003) and social network analysis (Mehler, and Skiena, 2009; Lin et al., 2009; Agichtein, and Liu, 2009; Ko et al., 2006; Wu, and Huberman 2004; Suh, and Kim, 2002; Park, and Choi, 2001), they often appear to be in two separate fields. Our study aims to better und...
Ionic Liquid Immobilized Organocatalysts for Asymmetric Reactions in Aqueous Media

Ionic liquids are organic salts with melting points typically below ambient or reaction temperature. The unique combination of physical properties of ionic liquids, such as lack of measurable vapor pressure, high thermal and chemical stability, make them ideal to be used as reusable homogenous support for catalysts. In addition, the solubility of ionic liquids in various reaction media can be controlled and easily fine-tuned by modification of the structures of their cations and anions. As a result, ionic liquid immobilized organocatalysts are very effective in aqueous media and can be separated easily from organic solvents, as well as aqueous phases by simply adjusting the polarity of the media. Ionic liquid immobilized organocatalysts are not only very versatile compounds that are effective catalysts for a wide spectrum of reactions, but are also environmentally friendly and recyclable organocatalysts. Herein, we provide a summary of the past decade in the area of asymmetric catalysis in aqueous media for a wide variety of reactions in which ionic liquid and related ammonium salt immobilized organocatalysts are used.
Optimal Trade Execution Under Stochastic Volatility and Liquidity

AbstractWe study the problem of optimally liquidating a financial position in a discrete-time model with stochastic volatility and liquidity. We consider the three cases where the objective is to minimize the expectation, an expected exponential or a mean-variance criterion of the implementation cost. In the first case, the optimal solution can be fully characterized by a forward-backward system of stochastic equations depending on conditional expectations of future liquidity. In the other two cases, we derive Bellman equations from which the optimal solutions can be obtained numerically by discretizing the control space. In all three cases, we compute optimal strategies for different simulated realizations of prices, volatility and liquidity and compare the outcomes to the ones produced by the deterministic strategies of Bertsimas and Lo (1998; Optimal control of execution costs. Journal of Financial Markets, 1, 1–50) and Almgren and Chriss (2001; Optimal execution of portfolio transactions. Journal of R...
Strong Coupling and the Cosmological Constant

The vanishing of the cosmological constant and the absence of a massless dilaton might be explained by a duality between a supersymmetric string vacuum in three dimensions and a nonsupersymmetric string vacuum in four dimensions.
Carbonate and Bicarbonate Ion Transport in Alkaline Anion Exchange Membranes

Abstract : Anion exchange membranes (AEMs) are being developed for potential use in fuel cell systems which include portable power applications. In a fuel cell, these membranes transport hydroxide ions from the cathode to the anode. If carbon dioxide is present, carbonate and bicarbonate ions can form, displacing the hydroxide ions. Among the challenges this presents, the carbonate and bicarbonate are less mobile than the hydroxide and therefore the ionic conductivity of the membrane suffers. A procedure is outlined to take data from a permeation based water flux experiment and determine diffusion coefficients and the ionic conductivity of the membrane. The water-membrane diffusion coefficients can be measured from a water flux experiment. Using principles from kinetic theory, the water-membrane diffusion coefficient can be converted to an appropriate ion-membrane diffusion coefficient. Finally, an equation derived from the dusty fluid model can be used to calculate the ionic conductivity of the membrane in different counter ion forms. The calculated ionic conductivities have been shown to agree well with reported values for proton and anion exchange membranes.
Low-Latency SINR-Based Data Gathering in Wireless Sensor Networks

Data gathering is a fundamental operation in various applications of wireless sensor networks (WSNs), where sensor nodes sense information and forward data to a sink node via multi-hop wireless communications. Typically, data in a WSN is relayed over a tree topology to the sink for effective data gathering. A number of tree-based data gathering schemes have been proposed in the literature, most of which aim at maximizing network lifetime. However, the timeliness and reliability of gathered data are also of great importance to many applications in WSNs. To achieve low-latency, high-reliability data gathering in WSNs, in this paper, we construct a data gathering tree based on a reliability model, schedule data transmissions for the links on the tree and assign transmitting power to each link accordingly. Since the reliability of a link is highly related to its signal to interference plus noise ratio (SINR), the SINR of all the currently used links on the data gathering tree should be greater than a threshold to guarantee high reliability. We formulate the joint problem of tree construction, link scheduling and power assignment for data gathering into an optimization problem, with the objective of minimizing data gathering latency. We show the problem is NP-hard and divide the problem into two subproblems: Constructing a low-latency data gathering tree; Jointly link scheduling and power assignment for the data gathering tree. We then propose a polynomial heuristic algorithm for each subproblem and conduct extensive simulations to verify the effectiveness of the proposed algorithms. Our simulation results show that the proposed algorithms achieve much lower data gathering latency than existing data gathering strategies while guaranteeing high reliability. Moreover, the algorithms also have a comparable energy efficiency and network lifetime to other algorithms.
String-like Lagrangians from a generalized geometry

This note will use Hitchin's generalized geometry and a model of axionic gravity developed by Warren Siegel in the mid-nineties to show that the construction of Lagrangians based on the inner product arising from the pairing of a vector and its dual can lead naturally to the low-energy Lagrangian of the bosonic string.
Controlled spontaneous emission

The problem of spontaneous emission is studied by a direct computer simulation of the dynamics of a combined system: atom + radiation field. The parameters of the discrete finite model, including up to 20k field oscillators, have been optimized by a comparison with the exact solution for the case when the oscillators have equidistant frequencies and equal coupling constants. Simulation of the effect of a multi-pulse sequence of phase kicks and emission by a pair of atoms shows that both the frequency and the linewidth of the emitted spectrum could be controlled.
Experimental and Numerical Investigation of Dynamic Instability in the Head Disk Interface at Proximity

As the flying height decreases to achieve greater areal density in hard disk drives, different proximity forces act on the air bearing slider, which results in fly height modulation and instability. Identifying and characterizing these forces has become important for achieving a stable fly height at proximity. One way to study these forces is by examining the fly height hysteresis, which is a result of many constituent phenomena. The difference in the touchdown and takeoff rpm (hysteresis) was monitored for different slider designs, varying the humidity and lubricant thickness of the disks, and the sliders were monitored for lubricant pickup while the disks were examined for lubricant depletion and modulation. Correlation was established between the observed hysteresis and different possible constituent phenomena. One such phenomenon was identified as the Intermolecular Force from the correlation between the lubricant thickness and the touchdown velocity. Simulations using 3D dynamic simulation software explain the experimental trends.
Planet Formation in Binaries: Dynamics of Planetesimals Perturbed by the Eccentric Protoplanetary Disk and the Secondary

Detections of planets in eccentric, close (separations of ~20 AU) binary systems such as α Cen or γ Cep provide an important test of planet formation theories. Gravitational perturbations from the companion are expected to excite high planetesimal eccentricities, resulting in destruction rather than growth of objects with sizes of up to several hundred kilometers in collisions of similar-sized bodies. It was recently suggested that the gravity of a massive axisymmetric gaseous disk in which planetesimals are embedded drives rapid precession of their orbits, suppressing eccentricity excitation. However, disks in binaries are themselves expected to be eccentric, leading to additional planetesimal excitation. Here we develop a secular theory of eccentricity evolution for planetesimals perturbed by the gravity of an elliptical protoplanetary disk (neglecting gas drag) and the companion. For the first time, we derive an expression for the disturbing function due to an eccentric disk, which can be used for a variety of other astrophysical problems. We obtain explicit analytical solutions for planetesimal eccentricity evolution neglecting gas drag and delineate four different regimes of dynamical excitation. We show that in systems with massive ( 10–2 M ☉) disks, planetesimal eccentricity is usually determined by the gravity of the eccentric disk alone, and is comparable to the disk eccentricity. As a result, the latter imposes a lower limit on collisional velocities of solids, making their growth problematic. In the absence of gas drag, this fragmentation barrier can be alleviated if the gaseous disk rapidly precesses or if its own self-gravity is efficient at lowering disk eccentricity.
CROWDSOURCING A WORD–EMOTION ASSOCIATION LEXICON

Even though considerable attention has been given to the polarity of words (positive and negative) and the creation of large polarity lexicons, research in emotion analysis has had to rely on limited and small emotion lexicons. In this paper, we show how the combined strength and wisdom of the crowds can be used to generate a large, high-quality, word–emotion and word–polarity association lexicon quickly and inexpensively. We enumerate the challenges in emotion annotation in a crowdsourcing scenario and propose solutions to address them. Most notably, in addition to questions about emotions associated with terms, we show how the inclusion of a word choice question can discourage malicious data entry, help to identify instances where the annotator may not be familiar with the target term (allowing us to reject such annotations), and help to obtain annotations at sense level (rather than at word level). We conducted experiments on how to formulate the emotion-annotation questions, and show that asking if a term is associated with an emotion leads to markedly higher interannotator agreement than that obtained by asking if a term evokes an emotion.
Homoclinic bifurcations for the Hénon map

Abstract Chaotic dynamics can be effectively studied by continuation from an anti-integrable limit. We use this limit to assign global symbols to orbits and use continuation from the limit to study their bifurcations. We find a bound on the parameter range for which the Henon map exhibits a complete binary horseshoe as well as a subshift of finite type. We classify homoclinic bifurcations, and study those for the area preserving case in detail. Simple forcing relations between homoclinic orbits are established. We show that a symmetry of the map gives rise to constraints on certain sequences of homoclinic bifurcations. Our numerical studies also identify the bifurcations that bound intervals on which the topological entropy is apparently constant.
Infrared spectra of group 14 hydrides in solid hydrogen: experimental observation of PbH4, Pb2H2, and Pb2H4.

Laser-ablated Si, Ge, Sn, and Pb atoms have been co-deposited with pure hydrogen at 3.5 K to form the group 14 hydrides. The initial SiH2 product reacts completely to SiH4, whereas substantial proportions of GeH2, SnH2, and PbH2 are trapped in solid hydrogen. Further hydrogen atom reactions form the trihydride radicals and tetrahydrides of Ge, Sn, and Pb. The observation of PbH4 at 1815 cm-1 and PbD4 at 1302 cm-1 is in agreement with the prediction of quantum chemical calculations for these unstable tetrahydride analogues of methane. In addition, new absorptions are observed for Pb2H2 and Pb2H4, which have dibridged structures based on quantum chemical calculations.
Supersonic Stall Flutter of High-Speed Fans

An analytical model is developed for predicting the onset of supersonic stall bending flutter in axial-flow compressors. The analysis is based on a modified two-dimensional, compressible, unsteady actuator disk theory. It is applied to a rotor blade row by considering a cascade of airfoils whose geometry and dynamic response coincide with those of a rotor blade element at 85 percent of the span height (measured from the hub). The rotor blades are assumed to be unshrouded (i.e., free standing) and to vibrate in their first flexural mode. The effects of shock waves and flow separation are included in the model through quasisteady, empirical, rotor total-pressure-loss and deviation-angle correlations. The actuator disk model predicts the unsteady aerodynamic force acting on the cascade blading as a function of the steady flow field entering the cascade and the geometry and dynamic response of the cascade. Calculations show that the present model predicts the existence of a bending flutter mode at supersonic inlet Mach numbers. This flutter mode is suppressed by increasing the reduced frequency of the system or by reducing the steady-state aerodynamic loading on the cascade. The validity of the model for predicting flutter is demonstrated by correlating the measured flutter boundary of a high-speed fan stage with its predicted boundary. This correlation uses a level of damping for the blade row (i.e., the log decrement of the rotor system) that is estimated from the experimental flutter data. The predicted flutter boundary is shown to be in good agreement with the measured boundary. These results show that the model can be used to estimate the relative stability between operating points of a given rotor system. If, in addition, a measure of the mechanical damping of the rotor system is available, the model can also be used to estimate the absolute stability at an operating point.
HETEROATOM-STABILIZED ALLYLIC CATIONS IN 4+3 CYCLOADDITIONS. A TANDEM PETERSON OLEFINATION/4+3 CYCLOADDITION REACTION

The readily available tertiary alcohols 4a-c react with selected dienes in the presence of titanium tetrachloride to give 4+3 cycloaddition products. The process is best rationalized as a Peterson olefination followed by allylic cation formation and 4+3 cycloaddition.
Graph wavelet alignment kernels for drug virtual screening.

In this paper, we introduce a novel statistical modeling technique for target property prediction, with applications to virtual screening and drug design. In our method, we use graphs to model chemical structures and apply a wavelet analysis of graphs to summarize features capturing graph local topology. We design a novel graph kernel function to utilize the topology features to build predictive models for chemicals via Support Vector Machine classifier. We call the new graph kernel a graph wavelet-alignment kernel. We have evaluated the efficacy of the wavelet-alignment kernel using a set of chemical structure–activity prediction benchmarks. Our results indicate that the use of the kernel function yields performance profiles comparable to, and sometimes exceeding that of the existing state-of-the-art chemical classification approaches. In addition, our results also show that the use of wavelet functions significantly decreases the computational costs for graph kernel computation with more than ten fold speedup.
A PECULIAR FLARING EPISODE OF CYGNUS X-1

Recent monitoring of Cyg X-1 with the Rossi X-Ray Timing Explorer (RXTE) revealed a period of intense flaring, which started in 2000 October and lasted until 2001 March. The source exhibited some quite unusual behaviors during this period. The soft X-ray flux of the source went up and down 3 times on a timescale of about 1 month, as discovered by the All-Sky Monitor aboard RXTE, before finally returning to the normal level (of the hard state). The observed spectral and temporal X-ray properties of Cyg X-1 are mostly intermediate between the canonical hard and soft states. This is known previously for strong X-ray flares; however, we show that the source did enter a period that resembles, in many ways, a sustained soft state during the last of the three flares. We make detailed comparisons between this flare and the 1996 state transition in terms of the observed X-ray properties, such as the flux-hardness correlation, X-ray spectrum, and power density spectrum. We point out the similarities and differences, and discuss possible implications of the results on our understanding of the phenomena of flares and state transitions associated with Cyg X-1.
Many-particle decays of α -chain structures in 24 Mg

We have searched for evidence of exotic cluster configurations in 24Mg resembling a linear chain of a particles in various many-particle final states of the 12C+12C system, including 12C(0 2 + )+12C(0 2 + ) and 8Be+16O*(4α). Such configurations are predicted to occur by a number of different theoretical models of the structure of 24Mg. An array of highly segmented double-sided silicon strip detectors permits detailed, high resolution reconstruction of these many-charged-particle final states.
Titanium Enolates of Thiazolidinethione Chiral Auxiliaries: Versatile Tools for Asymmetric Aldol Additions

[formula: see text] Asymmetric aldol additions using chlorotitanium enolates of thiazolidinethione propionates proceed with high diastereoselectivity for the "Evans" or "non-Evans" syn product depending on the nature and amount of the base used. With (-)-sparteine as the base, selectivities of 97:3 to > 99:1 were obtained for the Evans syn products with 2 equivalents of base and for the non-Evans syn when 1 equiv of base was employed. The thiazolidinethione auxiliaries are easily removed, and the aldol adducts can be readily transformed to various functional groups. Even direct reduction to the aldehyde with diisobutylaluminum hydride is possible.
Characterization of constitutional liquid film migration in nickel-base alloy 718

When multiphase alloys are rapidly heated, it is possible to cause melting of the interface between phases. This is called constitutional liquation if, during melting, the bulk composition is in a nonliquid region of the phase diagram but the tie-line between the liquating phases passes through a liquid region. The liquid produced during constitutional liquation can spread along grain boundaries and promote liquid film migration (LFM). This is known as constitutional liquid film migration (CLFM), which is thermodynamically similar to liquid film migration; however, mechanistically there are significant differences. Nickel-base alloy 718 has been studied to show the features of migration that are unique to CLFM. Experimentation consisted of heat-treating rods of alloy 718 to promote the trapping of niobium carbide particles on the grain boundaries. These samples were then subjected to isothermal treatments above their constitutional-liquation temperature, which produced CLFM of the grain boundaries. The movement of the liquid films away from their centers of curvature, the formation of a new solid solution behind the migrated liquid films, and the reversals of curvature of the migrated liquid films confirmed that CLFM was the phenomenon observed. The concentration of niobium behind the migrated liquid films for isothermal treatments below the solidus temperature was shown to be greater than the niobium concentration in the matrix. Above the solidus temperature, there was no increase in niobium concentration. The validity of the coherency strain hypothesis as the driving force for CLFM in alloy 718 is discussed.
Evolutionary growth of knowledge in path-breaking targeted therapies for lung cancer: radical innovations and structure of the new technological paradigm

Lung cancer is the second most common type of cancer and it has the highest mortality rate worldwide. The purpose of this paper is to analyse the evolutionary growth of knowledge of radical innovations to treat lung cancer which are generating a revolution in clinical practice. The patterns of these new anticancer drugs are evolving through an allometric process of knowledge growth, driven by scientific and technological advances in genetics, genomics and proteomics as well as by multiplicity of learning mechanisms in clinical research and practice. This study shows that traditional chemotherapy agents seem to have reached the maturity phase in the treatment of advanced non- small cell lung cancer because of the introduction of groundbreaking anticancer drugs. The current debate concerns uncertainties about the long-term effects of these radical innovations on carcinogenesis, the high cost of these drugs, and shrinking healthcare budgets. Nevertheless, these innovative treatments generate several benefits in terms of higher survival rate and quality of life. In addition, the structure, characteristics, and properties of the path-breaking technological paradigm to treat lung cancer can lay the foundations for a vital basic scientific framework for effective anticancer treatments in the not-too- distant future.
Mild Decarboxylative Allylation of Coumarins

Allyl esters of 3-carboxylcoumarins undergo facile decarboxylative coupling at just 25-50 degrees C. This represents the first extension of decarboxylative C-C bond-forming reactions to the coupling of aromatics with sp(3)-hybridized electrophiles. Finally, the same concept can be applied to the sp(2)-sp(3) couplings of pyrones and flavones. Thus, a variety of biologically important heteroaromatics can be readily functionalized without the need for strong bases or stoichiometric organometallics that are typically required for more standard cross-coupling reactions.
Bidding behavior in the price is right game: an experimental study

In this paper, we present an experimental test of a bidding game identical to the one seen on the television game show “The Price is Right”. Four players make sequential guesses about the price of an item and the player whose guess is closest to the price without exceeding it wins the item. Patterns of suboptimal behavior in our experimental data are consistent with field data from the actual game show analyzed by Berk, Hughson and Vandezande (1996). Several treatments that simplify the game are used to identify factors that cause subgame perfection to predict poorly.
Performance estimation of embedded software with instruction cache modeling

Embedded systems generally interact in some way with the outside world. This may involve measuring sensors and controlling actuators, communicating with other systems, or interacting with users. These functions impose real-time constraints on system design. Verification of these specifications requires computing an upper bound on the worst-case execution time (WCET) of a hardware/software system. Furthermore, it is critical to derive a tight upper bound on WCET in order to make efficient use of system resources.The problem of bounding WCET is particularly difficult on modern processors. These processors use cache-based memory systems that vary memory access time based on the dynamic memory access pattern of the program. This must be accurately modeled in order to tightly bound WCET. Several analysis methods have been proposed to bound WCET on processors with instruction caches. Existing approaches either search all possible program paths, an intractable problem, or they use highly pessimistic assumptions to limit the search space. In this paper we present a more effective method for modeling instruction cache activity and computing a tight bound on WCET. The method uses an integer linear programming formulation and does not require explicit enumeration of program paths. The method is implemented in the program cinderella and we present some experimental results of this implementation.
Review: Evidence for the effectiveness of surgery for low back pain, radiculopathy, and spinal stenosis is limited

Source Citation Chou R, Baisden J, Carragee EJ, et al. Surgery for low back pain: a review of the evidence for an American Pain Society clinical practice guideline. Spine. 2009;34:1094-109. 19363455
Broadcasting in ad hoc multiple access channels

We study broadcast in multiple access channels in dynamic adversarial settings. There is an unbounded supply of anonymous stations attached to a synchronous channel. There is an adversary who injects packets into stations to be broadcast on the channel. The adversary is restricted by injection rate, burstiness, and by how many passive stations can be simultaneously activated by providing them with packets. We consider deterministic distributed broadcast algorithms, which are further categorized by their properties. We investigate for which injection rates can algorithms attain bounded packet latency, when adversaries are restricted to be able to activate at most one station per round. The rates of algorithms we present make the increasing sequence consisting of 1 3 , 3 8 and 1 2 , reflecting the additional features of algorithms. We show that injection rate 3 4 cannot be handled with bounded packet latency.
Gauged SO(3) family symmetry and squark mass degeneracy

Abstract It is shown that a gauged SO(3) family symmetry can suppress flavor-changing processes from squark-mass non-degeneracy to an acceptable level. The potentially dangerous SO(3) D-tems can be rendered harmless if the CP-violating phases appearing in the SO(3)-breaking sector are small, which can naturally be the case if CP is a spontaneously broken symmetry. This approach has certain advantages over models based on global or non-abelian discrete symmetries, and dovetails with some recent proposals for explaining the pattern of quark and lepton masses. Moreover this approach relates the near-degeneracy of the squark masses to an approximate CP invariance which can also explain the smallness of the electron and neutron electric dipole moments.
Synthesis of the carbapenam ring system via carbene mediated rearrangement of an n-benzyloxy-β-lactam

The α-diazoester1 in the presence of catalytic Rh2(OAc)4 was converted to the carbapenam2. The synthesis of1 and a proposed mechanism are described.
The physics of baseball

The illumination of the ordinary—of why the sky is blue or why the stars shine—is not the least important role of physics and physicists. Then can't we add to the list of deeper queries some of the questions that seemed so important to me in my youth: How can Babe Ruth hit so many home runs? What makes Carl Hubble's curveball and screwball swerve in their trips to the plate? And if baseball plays no known role in the fundamental structure of the universe (see The Iowa Baseball Confederacy by W. P. Kinsella for a contrary position), it is not of trivial importance in the perception and appreciation of that universe by some of its inhabitants. Although not quite so important now, in the period between the Civil War and World War II baseball was a significant part of what defined the United States. Forty years ago, Jacques Barzun, a preeminent student of American culture and a native of France, said, “Whoever wants to know… America had better learn baseball.” But, even as the game itself is subtle and comple...
More like each other than anyone else? A cross-cultural study of entrepreneurial perceptions

Abstract This article examines the idea that there is a basic set of beliefs that entrepreneurs hold about themselves and about others in their society that , from the perspective of the entrepreneur, differentiate the two. The article suggests that this set of beliefs transcends cultures, and that these perceived differences may be linked to entrepreneurial activity. Analysis of survey responses from over 700 entrepreneurs in nine countries found that even among culturally very different societies there is a core set of perceptions, common across countries, that entrepreneurs hold about others in their countries. This supports the first two parts of the proposition, and suggests that entrepreneurial behavior may indeed stem from a pervasive set of entrepreneurial beliefs .
Do the Electrons and Ions in X-Ray Clusters Share the Same Temperature?

The virialization shock around an X-ray cluster primarily heats the ions, since they carry most of the kinetic energy of the infalling gas. Subsequently, the ions share their thermal energy with the electrons through Coulomb collisions. We quantify the expected temperature difference between the electrons and ions as a function of radius and time, based on a spherical self-similar model for the accretion of gas by a cluster in an Ω = 1, h50 = 1 universe. Clusters with X-ray temperatures TX = 4-10 × 107 K show noticeable differences between their electron and ion temperatures at radii 2 Mpc. High-resolution spectroscopy with future X-ray satellites such as Astro-E may be able to determine the ion temperature in intracluster gas from the width of its X-ray emission lines and compare it to the electron temperature as inferred from the free-free emission spectrum. Any difference between these temperatures can be used to date the period of time that has passed since the infalling gas joined the cluster.
Biliary tract obstruction The role of spiral CT in detection and definition of disease

The purpose of this study was to assess the efficacy of spiral computed tomography (CT) in determining the etiology of biliary tract obstruction. Spiral CT studies performed over a 9-month period in 42 consecutive patients with suspected biliary tract obstruction were reviewed. Analysis of scans included localizing the obstruction and then defining a specific etiology. Pertinent associated findings such as porta hepatis or peripancreatic adenopathy, hepatic or peritoneal metastases, and pancreatic pseudocyst or abscess formation were also assessed. Spiral CT demonstrated the level of obstruction in all 30 patients in whom there was biliary tract dilatation. Thirty-two diagnoses were rendered in 30 patients, with specific obstructing lesions identified in 28 instances (88%). Twenty-five (78%) of 32 specific pathological diagnoses were correct. The positive predictive value for neoplasms in the pancreatic head was 100% (n = 17). Two patients with characteristic CT changes of sclerosing cholangitis were diagnosed as having superimposed cholangiocarcinoma, although the results of biopsies for neoplasm were negative. The sensitivity of spiral CT for detection of common duct calculi was 67% (n = 3). Due to optimal contrast enhancement of both hepatic and pancreatic parenchyma, spiral CT enables excellent visualization of the biliary system and provides a specific explanation for biliary tract obstruction in nearly all cases. Spiral CT can usually distinguish neoplastic from nonneoplastic causes of jaundice. When distal common duct obstruction is detected in the absence of an identifiable mass or focal ductal wall thickening, neoplasia is unlikely. It is difficult to exclude sclerosing cholangitis from cholangiocarcinoma on the basis of spiral CT findings, and in these patients, biopsy or close follow-up is recommended to exclude the possibility of a biliary neoplasm.
Spatial whitening framework for distributed estimation

Designing resource allocation strategies for power constrained sensor network in the presence of correlated data often gives rise to intractable problem formulations. In such situations, applying well-known strategies derived from conditional-independence assumption may turn out to be fairly suboptimal. In this paper, we address this issue by proposing an adjacency-based spatial whitening scheme, where each sensor exchanges its observation with their neighbors prior to encoding their own private information and transmitting it to the fusion center. We comment on the computational limitations for obtaining the optimal whitening transformation, and propose an iterative optimization scheme to achieve the same for large networks. We demonstrate the efficacy of the whitening framework by considering the example of bit-allocation for distributed estimation.
A new look at attractive/repulsive junctions and cleavage crack formation in BCC materials

Abstract In this paper, the formation of sessile cleavage crack nuclei of the type a 〈 0 0 1 〉 from glissile dislocations of the type a 2 〈 1 1 1 〉 is considered. While an energy reduction is necessary, formation of a nucleus necessarily involves interaction forces. The propensity for cleavage crack formation in BCC crystals is explained in terms of the fact that glide dislocations inevitably interact to form microcrack nuclei. The calculated dislocation interactions are consistent with the observation that cleavage cracking in BCC alloys on {0 0 1}-type planes requires plastic deformation. Continued growth of a microcrack is examined in terms of distance between pre-existing sessile dislocations and the external force necessary to drive glissile dislocations to a common junction. Pre-existing sessile dislocations significantly alter the orientation dependence of the glide force on the glissile dislocations from that computed for glissile/glissile interactions. An important feature of this work was to provide a general framework for the computation of dislocation interactions using closed-form solutions in a computational environment.
Rapid acquisition pair distribution function (RA-PDF) analysis.

An image-plate (IP) detector coupled with high-energy synchrotron radiation was used for atomic pair distribution function (PDF) analysis, with high probed momentum transfer Qmax ≤ 28.5 A−1, from crystalline materials. Materials with different structural complexities were measured to test the validity of the quantitative data analysis. Experimental results are presented for crystalline Ni, crystalline α-AlF3, and the layered Aurivillius type oxides α-Bi4V2O11 and γ-Bi4V1.7Ti0.3O10.85. Overall, the diffraction patterns show good counting statistics, with measuring time from one to tens of seconds. The PDFs obtained are of high quality. Structures may be refined from these PDFs, and the structural models are consistent with the published literature. Data sets from similar samples are highly reproducible.
Modeling the Effective Elastic Behavior of a Transversely Cracked Laminated Composite

The solution for the stress state present in the vicinity of transverse matrix cracks within a composite laminate is typically obtained by assuming a regular crack spacing geometry for the problem and applying a shear-lag analysis. In order to explore the validity of this underlying assumption, the probability density function for the location of the next transverse matrix crack within a crack bounded region is examined. The regular crack spacing assumption is shown to be reasonable from an engineering point of view. Continuing with this assumption, a generalized shear-lag model for multilayer, off-axis laminates subjected to full in-plane loads is developed. This model is used to quantitatively evaluate the effective elastic properties of the damaged material. The results are applicable to materials such as ceramic matrix or polymer matrix unidirectional fiber systems where damage in the form of transverse matrix cracks arises.
ULTRA‐SHARP SOLUTION OF THE SMITH‐HUTTON PROBLEM

In 1982, Smith and Hutton published comparative results of several different convection‐diffusion schemes applied to a specially devised test problem involving near‐discontinuities and strong streamline curvature. First‐order methods showed significant artificial diffusion, whereas higher‐order methods gave less smearing but had a tendency to overshoot and oscillate. Perhaps because unphysical oscillations are more obvious than unphysical smearing, the intervening period has seen a rise in popularity of low‐order artificially diffusive schemes, especially in the numerical heat‐transfer industry. This paper presents an alternative strategy of using non‐artificially diffusive higher‐order methods, while maintaining strictly monotonic transitions through the use of simple flux‐limiter constraints. Limited third‐order upwinding is usually found to be the most cost‐effective basic convection scheme. Tighter resolution of discontinuities can be obtained at little additional cost by using automatic adaptive stencil expansion to higher order in local regions, as needed.
CMIP5 Projections of Arctic Amplification, of the North American/North Atlantic Circulation, and of Their Relationship

AbstractRecent studies have hypothesized that Arctic amplification, the enhanced warming of the Arctic region compared to the rest of the globe, will cause changes in midlatitude weather over the twenty-first century. This study exploits the recently completed phase 5 of the Coupled Model Intercomparison Project (CMIP5) and examines 27 state-of-the-art climate models to determine if their projected changes in the midlatitude circulation are consistent with the hypothesized impact of Arctic amplification over North America and the North Atlantic.Under the largest future greenhouse forcing (RCP8.5), it is found that every model, in every season, exhibits Arctic amplification by 2100. At the same time, the projected circulation responses are either opposite in sign to those hypothesized or too widely spread among the models to discern any robust change. However, in a few seasons and for some of the circulation metrics examined, correlations are found between the model spread in Arctic amplification and the m...
Persistent global power fluctuations near a dynamic transition in electroconvection.

This is a study of the global fluctuations in power injection and light transmission through a liquid crystal just above the onset of electroconvection. The source of the fluctuations is identified as the creation and annihilation of defects. They are spatially uncorrelated and yet temporally correlated. The temporal correlation is seen to persist for extremely long times. There seems to be an especially close relation between defect creation or annihilation in electroconvection and thermal plumes in Rayleigh-Benard convection.
Observed and Physical Properties of Core-Collapse Supernovae

I use photometry and spectroscopy data for 24 Type II plateau supernovae (SNe IIP) to examine their observed and physical properties. This data set shows that these objects encompass a wide range of ~5 mag in their plateau luminosities, their expansion velocities vary by a factor of 5, and the nickel masses produced in these explosions go from 0.0016 to 0.26 M☉. From a subset of 16 objects I find that the explosion energies vary between 0.6 × 1051 and 5.5 × 1051 ergs, the ejected masses encompass the range 14-56 M☉, and the progenitors' radii go from 80 to 600 R☉. Despite this great diversity, several regularities emerge, which reveal that there is a continuum in the properties of these objects from the faint, low-energy, nickel-poor SNe 1997D and 1999br, to the bright, high-energy, nickel-rich SN 1992am. This study provides evidence that more massive progenitors produce more energetic explosions, thus suggesting that the outcome of the core collapse is somewhat determined by the envelope mass. I also find that SNe with greater energies produce more nickel. Similar relationships appear to hold for SNe Ib/c, which suggests that both SNe II and SNe Ib/c share the same core physics. When the whole sample of core-collapse objects is considered, there is a continuous distribution of energies below 8 × 1051 ergs. Far above in energy scale and nickel production lies the extreme hypernova 1998bw, the only SN firmly associated with a gamma-ray burst.
Heisenberg algebra and a graphical calculus

A new calculus of planar diagrams involving diagrammatics for biadjoint functors and degenerate affine Hecke algebras is introduced. The calculus leads to an additive monoidal category whose Grothendieck ring contains an integral form of the Heisenberg algebra in infinitely many variables. We construct bases of vector spaces of morphisms between products of generating objects in this category.
Reaction- Limited Sintering in Nearly Saturated Environments

We study the shape and growth rate of necks between sintered spheres with dissolution–precipitation dynamics in the reaction-limited regime. We determine the critical shape that separates those initial neck shapes that can sinter from those that necessarily dissolve, as well as the asymptotic evolving shape of sinters far from the critical shape. We compare our results with past results for the asymptotic neck shape in closely related but more complicated models of surface dynamics; in particular, we confirm a scaling conjecture, originally due to Kuczinsky. Finally, we consider the relevance of this problem to the diagenesis of sedimentary rocks and other applications.