cssi/SciSciGPT-SciSciNet huggingface dataset:
Probabilistic and statistical relationships between number of vehicles and number of visitors at a geologic site in a National Park

The National Park Service needs to establish in all of the national parks how large the parking lots should be in order to enjoy and preserve our natural resources, for example, in the Delicate Arch in the Arches National Park. Probabilistic and statistical relationships were developed between the number of vehicles (N) at one time in the Wolfe Ranch parking lot and the number of visitors (X) at Delicate Arch 1.5 miles away in the Arches National Park, southeastern Utah. The value of N is determined such that 30 or more visitors are at the arch only 10% of the time.
Unanticipated benefits of automotive emission control : reduction in fatalities by motor vehicle exhaust gas

In 1970, before the implementation of strict controls on emissions in motor vehicle exhaust gas (MVEG), the annual USA incidence of fatal accidents by carbon monoxide in the MVEG was approximately 800 and that of suicides approximately 2000 (somewhat less than 10% of total suicides). In 1987, there were approximately 400 fatal accidents and approximately 2700 suicides by MVEG. Accounting for the growth in population and vehicle registration, the yearly lives saved in accidents by MVEG were approximately 1200 in 1987 and avoided suicides approximately 1400. The decrease in accidents continues unabated while the decrease in expected suicides by MVEG reached a plateau in 1981-1983. The reasons for this disparity are discussed. Juxtaposition of these results with the projected cancer risk avoidance of less than 500 annually in 2005 (as compared with 1986) plainly shows that, in terms of mortality, the unanticipated benefits of emission control far overshadow the intended benefits. With the spread of MVEG control these benefits will accrue worldwide.
BRST quantisation of the N = 2 string in a real spacetime structure

Abstract We study the N = 2 string with a real structure on the (2,2) spacetime, using BRST methods. Several new features emerge. In the diagonal basis, the operator exp ( λ ∫ z J tot ), which is associated with the moduli for the U(1) gauge field on the world-sheet, is local and it relates the physical operators in the NS and R sectors. However, the picture-changing operators are non-invertible in this case, and physical operators in different pictures cannot be identified. The three-point interactions of all physical operators lead to three different types of amplitudes, which can be effectively described by the interactions of a scalar NS operator and a bosonic spinorial R operator. In the off-diagonal bases for the fermionic currents, the picture-changing operators are invertible, and hence physical operators in different pictures can be identified. However, now there is no local operator exp ( λ ∫ z J tot) that relates the physical operators in different sectors. The physical spectrum is thus described by one scalar NS operator and one spinorial R operator. The NS and R operators give rise to different types of three-point amplitudes, and thus cannot be identified.
Improved Hardy and Rellich inequalities on Riemannian manifolds

In this paper we establish improved Hardy and Rellich type inequalities on a Riemannian manifold M. Furthermore, we also obtain sharp constants for improved Hardy and Rellich type inequalities on the hyperbolic space ℍ n .
Scintillator-fiber charged-particle track-imaging detector

A scintillator-fiber charged-particle track-imaging detector was developed using a bundle of square cross section plastic scintillator fiber optics, proximity focused onto an image intensified charge injection device (CID) camera. The tracks of charged particle penetrating into the scintillator fiber bundle are projected onto the CID camera and the imaging information is read out in video format. The detector was exposed to beams of 15 MeV protons and relativistic Neon, Manganese, and Gold nuclei and images of their tracks were obtained. Details of the detector technique, properties of the tracks obtained, and preliminary range measurements of 15 MeV protons stopping in the fiber bundle are presented.
Bunching instability of rotating relativistic electron layers and coherent synchrotron radiation.

We study the stability of a collisionless, relativistic, finite-strength, cylindrical layer of charged particles in free space by solving the linearized Vlasov-Maxwell equations and compute the power of the emitted electromagnetic waves. The layer is rotating in an external magnetic field parallel to the layer. This system is of interest to understanding the high brightness temperature of pulsars which cannot be explained by an incoherent radiation mechanism. Coherent synchrotron radiation has also been observed recently in bunch compressors used in particle accelerators. We consider equilibrium layers with a 'thermal' energy spread and therefore a nonzero radial thickness. The particles interact with their retarded electromagnetic self-fields. The effect of the betatron oscillations is retained. A short azimuthal wavelength instability is found which causes a modulation of the charge and current densities. The growth rate is found to be an increasing function of the azimuthal wave number, a decreasing function of the Lorentz factor, and proportional to the square root of the total number of electrons. We argue that the growth of the unstable perturbation saturates when the trapping frequency of electrons in the wave becomes comparable to the growth rate. Owing to this saturation we can predict the radiation spectrum formore » a given set of parameters. Our predicted brightness temperatures are proportional to the square of the number of particles and scale by the inverse five-third power of the azimuthal wave number which is in rough accord with the observed spectra of radio pulsars.« less
World food: Myth and reality

Abstract This introductory paper tries to dispel some of the myths surrounding the world food situation and to lay a foundation for further analyses of real problems. The author presents arguments to dispel three myths which have tended to obscure the real issues: (1) the myth of imminent global starvation; (2) the myth of the so-called ‘Tragedy of the Commons’; (3) the myth of the food-population race. He sees the essence of the problem in terms of the income/employment dilemma. Prescribing increased economic participation — more and better paying jobs — i.e. development leading to widely shared benefits, he sets out possible guidelines to be followed by agencies concerned with food and agriculture.
Halide adsorption on single-crystal silver substrates: dynamic simulations and ab initio density functional theory

We investigate the static and dynamic behaviors of a Br adlayer electrochemically deposited onto single-crystal Ag(100) using an off-lattice model of the adlayer. Unlike previous studies using a lattice-gas model, the off-lattice model allows adparticles to be located at any position within a two-dimensional approximation to the substrate. Interactions with the substrate are approximated by a corrugation potential. Using density functional theory (DFT) to calculate surface binding energies, a sinusoidal approximation to the corrugation potential is constructed. A variety of techniques, including Monte Carlo and Langevin simulations, are used to study the behavior of the adlayer. The lateral root-mean-square (rms) deviation of the adparticles from the binding sites is presented along with equilibrium coverage isotherms, and the thermally activated Arrhenius barrier-hopping model used in previous dynamic Monte Carlo simulations is tested.
The distribution of non-commutative Rademacher series

We give a formula for the tail of the distribution of the non-commutative Rademacher series, which generalizes the result that is already available in the commutative case. As a result, we are able to calculate the norm of these series in many rearrangement invariant spaces, generalizing work of Pisier and Rodin and Semyonov.
MiniBooNE: Status of the booster neutrino experiment

Abstract MiniBooNE is preparing to search for vμ → ve oscillations at Fermilab. The experiment is designed to make a conclusive statement about LSND's neutrino oscillation evidence. We give a status report on the preparation of the experiment and outline the experimental prospects.
Frequency-domain adaptive iterative image restoration and evaluation of the regularization parameter

An important consideration in regularized image restoration is the evaluation of the regularization parameter. Various techniques exist in the literature for the evaluation of this parameter, which depend on the assumed prior knowledge about the problem. These techniques evaluate the regularization parameter either at a separate preprocessing step or by iterating based on the completely restored image, therefore requiring many restorations of the image with different values of the regularization parameter. The authors propose a nonlinear frequency-domain adaptive regularized iterative image restoration algorithm. According to this algorithm a regularization circulant matrix is used that corresponds to the assignment of a regularization parameter to each discrete frequency. Therefore, each frequency component is appropriately regularized. The resulting algorithm produces more accurate results and converges considerably faster than the algorithm that uses one regularization parameter for all frequencies. The regularization matrix is updated at each iteration step, based on the partially restored image. No prior knowledge about the image or the noise is required. The development of the algorithm is based on a set-theoretic regularization approach, where bounds on the weighted error residual and stabilizing functional are updated in the frequency domain at each iteration step. The proposed algorithm is analyzed theoretically and tested experimentally. Sufficient conditions for convergence are obtained in terms of a control parameter, which is specified by the conditions for convergence and optimality of the regularization parameters at each discrete frequency location. Finally the proposed algorithm is compared experimentally with other related algorithms.
Synthesis and separation of diastereomers of uridine 2', 3'-cyclic boranophosphate

The first boron-containing 2',3'-cyclic phosphate-modified analogue, uridine 2',3'-cyclic boranophosphate (2',3'-cyclic-UMPB), was synthesized. 5'-O-Protected uridine was cyclophosphorylated by diphenyl H-phosphonate to yield uridine 2',3'-cyclic H-phosphonate, which upon silylation followed by boronation and subsequent acid treatment gave 2',3'-cyclic-UMPB in high yield. The two diastereomers of 2',3'-cyclic-UMPB were separated by HPLC. An alternative method for synthesis of uridine 2',3'-cyclic phosphorothioate (2',3'-cyclic-UMPS) via H-phosphonate was also described.
Marketing management in an islamic banking environment: in search of an innovative marketing concept

International banks are aggressively utilising the marketing concept in order to respond to an increasingly competitive industry. Banks in the Middle East, as in many developing regions, are seeking to become major players in the marketplace. Unique cultural priorities, lifestyles, buyer decision‐making factors, economic development goals, legal environment, and religious conditions require utilisation of appropriate bank marketing strategies that respond to the region's needs. A model of marketing innovation for managers to evaluate environmental factors and adoption/ implementation processes associated with survival and growth of the Arab banking industry is provided.
Sustainable development goals for global health: facilitating good governance in a complex environment

Increasing complexity is following in the wake of rampant globalization. Thus, the discussion about Sustainable Development Goals (SDGs) requires new thinking that departs from a critique of current policy tools in exploration of a complexity-friendly approach. This article argues that potential SDGs should: treat stakeholders, like states, business and civil society actors, as agents on different aggregate levels of networks; incorporate good governance processes that facilitate early involvement of relevant resources, as well as equitable participation, consultative processes, and regular policy and programme implementation reviews; anchor adoption and enforcement of such rules to democratic processes in accountable organizations; and include comprehensive systems evaluations, including procedural indicators. A global framework convention for health could be a suitable instrument for handling some of the challenges related to the governance of a complex environment. It could structure and legitimize government involvement, engage stakeholders, arrange deliberation and decision-making processes with due participation and regular policy review, and define minimum standards for health services. A monitoring scheme could ensure that agents in networks comply according to whole-systems targets, locally defined outcome indicators, and process indicators, thus resolving the paradox of government control vs. local policy space. A convention could thus exploit the energy created in the encounter between civil society, international organizations and national authorities.
Optimal operating conditions and configurations for humidification–dehumidification desalination cycles

Abstract This article applies nonlinear programming techniques to optimize humidification–dehumidification (HD) desalination cycles for operating conditions that result in maximum gained output ratio (GOR). Closed air open water as well as open air open water cycles, each with either an air or a water heater, were considered in this analysis. Numerical optimization resulted in a substantial increase in GOR for all four cycle types compared to previous best-case conditions found using heuristic studies. The GOR of the cycles was found to decrease with increasing component terminal temperature difference (TTD). In addition, different cycles perform best at different temperature differences. Optimization also revealed that some counterintuitive design configurations can result in superior performance under the appropriate operating conditions.
Effects of Nose Bluntness on Hypersonic Boundary-Layer Receptivity and Stability over Cones

The receptivity to freestream acoustic disturbances and the stability properties of hypersonic boundary layers are numerically investigated for boundary-layer flows over a 5 straight cone at a freestream Mach number of 6.0. To compute the shock and the interaction of the shock with the instability waves, the Navier-Stokes equations in axisymmetric coordinates were solved. In the governing equations, inviscid and viscous flux vectors are discretized using a fifth-order accurate weighted-essentially-non-oscillatory scheme. A third-order accurate total-variation-diminishing Runge-Kutta scheme is employed for time integration. After the mean flow field is computed, disturbances are introduced at the upstream end of the computational domain. The appearance of instability waves near the nose region and the receptivity of the boundary layer with respect to slow mode acoustic waves are investigated. Computations confirm the stabilizing effect of nose bluntness and the role of the entropy layer in the delay of boundary-layer transition. The current solutions, compared with experimental observations and other computational results, exhibit good agreement.
Information spreading in interacting string field theory

Abstract The commutator of string fields is considered in the context of light cone string field theory. It is shown that the commutator is in general non-vanishing outside the string light cone. This could have profound implications for our understanding of the localization of information in quantum gravity.
The c/a Ratio in Quenched Fe-C and Fe-N Steels - A Heuristic Story

The body-centered tetragonal (BCT) structure in quenched Fe-C steels is usually illustrated to show a linear change in the c and a axes with an increase in carbon content from 0 to 1.4%C. The work of Campbell and Fink, however, shows that this continuous linear relationship is not correct. Rather, it was shown that the body-centered-cubic (BCC) structure is the stable structure from 0 to 0.6 wt%C with the c/a ratio equal to unity. An abrupt change in the c/a ratio to 1.02 occurs at 0.6 wt%C. The BCT structure forms, and the c/a ratio increases with further increase in carbon content. An identical observation is noted in quenched Fe-N steels. This discontinuity is explained by a change in the transformation process. It is proposed that a two-step transformation process occurs in the low carbon region, with the FCC first transforming to HCP and then from HCP to BCC. In the high carbon region, the FCC structure transforms to the BCT structure. The results are explained with the Engel-Brewer theory of valence and crystal structure of the elements. An understanding of the strength of quenched iron-carbon steels plays a key role in the proposed explanation of the c/a anomaly based on interstitial solutes and precipitates.
Oxidation kinetics of plutonium in air: consequences for environmental dispersal

Abstract Kinetic studies show that plutonium corrosion in air is catalyzed by plutonium hydride on the metal surface and causes storage containers to fail. The reaction initiates at 25°C, indiscriminately consumes both O 2 and N 2 , and transforms Pu into a dispersible product at a 10 7 –10 10 faster rate (0.6±0.1 g Pu/cm 2 min) than normal air oxidation. The catalyzed reaction of O 2 advances into the metal at a linear rate of 2.9 m/h. Rate equations and particle size data for atmospheric and catalyzed corrosion at temperatures up to 3500°C provide a technical basis for assessing the dispersal hazard posed by plutonium metal.
Synthesis and characterization of nanoscale molybdenum sulfide catalysts by controlled gas phase decomposition of Mo(CO)(6) and H2S

Molybdenum sulfide catalysts with surface areas ranging from 16 to 120 m2/g were prepared by the thermal decomposition of Mo(CO)6 and H2S vapors in a specially designed tubular reactor system. The ...
Hyperfine mass splittings of baryons containing a heavy quark in large N QCD

Abstract The hyperfine mass splittings of baryons containing a heavy quark are derived at leading order in large N QCD. Hyperfine splittings either preserve or violate heavy quark spin symmetry. Previous work proves that the splittings which preserve heavy quark spin symmetry are proportional to J 2 at order 1 N , where J is the angular momentum of thelight degrees of freedom of the baryon. This work proves that the splittings which violate heavy quark spin symmetry are proportional to J·S Q at order 1/ Nm Q in the 1 N and 1 m Q expansions.
Orbifold compactness for spaces of Riemannian metrics and applications

This work proves certain general orbifold compactness results for spaces of Riemannian metrics, generalizing earlier results along these lines for Einstein metrics or metrics with bounded Ricci curvature. This is then applied to prove such compactness for spaces of Bach-flat (for example half-conformally flat) metrics on 4-manifolds, and related results for metrics which are critical points of other natural Riemannian functionals on the space of metrics.
Coordination in Tree Adjoining Grammars: formalization and implementation

In this paper we show that an account for coordination can be constructed using the derivation structures in a lexicalized Tree Adjoining Grammar (LTAG). We present a notion of derivation in LTAGs that preserves the notion of fixed constituency in the LTAG lexicon while providing the flexibility needed for coordination phenomena. We also discuss the construction of a practical parser for LTAGs that can handle coordination including cases of non-constituent coordination.
Convergence Behavior of Surface Evolver Applied to a Generic Propellant-Management Device

Design of surface-tension propellant-management devices for acquisition and control of liquid propellants in weightless periods of space e ight is a science with few analytical tools. One tool used increasingly is Surface Evolver. SurfaceEvolver can beused to solve the three-dimensional e uid statics problems necessary to characterize propellant-management device performance in weightlessness. Because of the interactive labor involved with running Surface Evolver , convergence and grid-size dependence issues can be expensive to explore for each tank and propellant-management device vane geometry. Results presented are of an investigation of convergence, gridsize dependence, consistency, and use of symmetry planes on Surface Evolver modeling of propellant distributions in a generic vane-type propellant-management device.
Dynamic Adverse Selection: A Theory of Illiquidity, Fire Sales, and Flight to Quality

We develop a dynamic equilibrium model of asset markets with adverse selection. There exists a unique equilibrium in which better quality assets trade at higher prices but with a lower price-dividend ratio in less liquid markets. Sellers of high-quality assets signal quality by accepting a lower trading probability. We show how the distribution of sellers’ private information affects an asset’s price and liquidity, how a change in that distribution can cause a �耀re sale and a �耀ight to quality , and how asset purchase and subsidy programs may raise prices and liquidity and reverse the �耀ight to quality. (JEL D82, G12) This paper develops a dynamic equilibrium model of asset markets with adverse selection. The owners of heterogeneous assets are privately informed about the quality of their assets. Sellers set prices for their assets recognizing that sales may be rationed at high prices. Buyers set prices recognizing that the quality of available assets may depend on the price selected. In equilibrium, sellers of high quality assets are willing to set a high price despite the low sale probability because the continuation value from failing to sell a high quality asset is high; conversely, sellers of low quality assets opt for a low price. Buyers are indifferent between paying a low price for a low quality asset and a high price for a high quality asset. We prove these results in a deliberately stylized dynamic general equilibrium framework. Assets are perfectly durable and pay a constant dividend each period, some amount of a perfectly perishable consumption good. Better quality assets pay a higher dividend but only the asset’s current owner observes the dividend. This is the source of private information and the root of the adverse selection problem, as in Akerlof (1970). The only permissible trades are between the consumption good and the asset. Individuals are risk-neutral and have a discount factor that changes over time, independently across individuals, creating gains from trade. Finally, discount factors are observable, which ensures that patient individuals never sell assets since there are no gains from trade. We believe this framework is useful for capturing
Gamma-Ray Spectral State Transitions of GRO J1719-24

We report the results of an in-depth study of the long-term soft gamma-ray (30 keV to 1.7 MeV) flux and spectral variability of the transient source GRO J1719-24 that was first discovered by BATSE and SIGMA in the fall of 1993. Our results were obtained from the JPL BATSE-EBOP database covering a 1000 day period between 1993 January 13 and 1995 October 10. During this period, the source underwent a major outburst in the fall of 1993 when the 35-100 keV flux rose from a quiescent state of less than 16 mcrab before 1993 September 17 to a level of 1.5 crab on October 3. The source remained in this high-intensity state over the next approx. 70 days, during which the 35-100 keV flux decreased monotonically by 33% to 1 crab on December 12, then decreased sharply to the pretransition quiescent level of 44 mcrab on December 21, where it remained until 1994 September 5. During a 400 day period between 1994 September 5 and 1995 October 10, the source again underwent a series of five transitions when the 35-100 keV flux increased to low-intensity levels of 200 400 mcrab, a factor of 4-7 times lower than what was observed in 1993. The low- and high-intensity states were characterized by two different spectral shapes. The low-state spectra are described by a power law with a spectral index of approx. 2. The high-state spectra, on the other hand, have two components: a thermal Comptonized shape below approx. 200 keV with electron temperature k(sub Te) of approx. 37 keV and optical depth tau approx. 2.8, and a soft power-law tail with photon index of 3.4 above 200 keV that extends to approx. 500 keV. The softer high-intensity spectrum and the harder low-intensity spectrum intersect at approx. 400 keV. The nonthermal power-law gamma-ray component in both the high- and low-intensity spectra suggests that the persistent nonthermal emission source is coupled to the hot and variable thermal emission source in the system. Furthermore, the correlation of the spectral characteristics with the high- and low-intensity states resembles that seen in two other gamma-ray emitting black hole candidates, GRO J0422+32 and Cygnus X-1, suggesting that perhaps similar system configurations and processes are occurring in these systems. Possible scenarios for interpreting these behaviors are discussed.
Using hindsight in medical decision making

As the clinical picture of a patient evolves over time, more information becomes available. Certain procedure require time to perform, causing delay between the time when the tests are ordered and when the results are available. Furthermore, as the patient's condition changes over time, serial measurements can be made. The availability of more data allows a more accurate assessment of the patient. Uncertainties, guesses or errors that were made early in the clinical course of patient care can also be identified and resolved when more information is available. Reasoning with a stream of data that changes over time presents a challenge to the designers of expert systems. The use of hindsight in expert system requires that appropriate attention be paid to the temporal relations of the data and that care is exercised in revising decision. I present a data-dependency system, the Temporal Control Structure (TCS), designed to support reasoning with data changing over time and show how it can be used to implement reasoning by hindsight.
Marketing Specialty Hogs: A Comparative Analysis of Two Firms from Iowa

We study business organization and coordination of specialty-market hog production using a comparative analysis of two Iowa firms marketing niche pork. We analyze each firm's management of five key organizational challenges: planning and logistics, quality assurance, process verification and management of “credence attributes,” business structure, and profit sharing. Although each firm is engaged in essentially the same activity, there are substantial differences across the two firms in the way production and marketing are coordinated. These differences are partly explained by the relative size and age of each firm, but also by the formal organizational separation between marketing and production activities in one of the firms.
Ultracompact X-ray binaries with neon-rich degenerate donors

There are three low-mass X-ray binaries (4U 0614+091, 2S 0918-549, and 4U 1543-624) for which broad-line emission near 0.7 keV was previously reported. A recent high-resolution observation of 4U 0614+091 with the Chandra Low-Energy Transmission Grating Spectrometer (LETGS) found evidence of an unusually high Ne/O abundance ratio along the line of sight but failed to detect the previously reported 0.7 keV feature. We have made a search of archival ASCA spectra and identified a fourth source with the 0.7 keV feature, the 20 minute ultracompact binary 4U 1850-087. In all four of these sources, the 0.7 keV residual is eliminated from the ASCA spectra by allowing excess photoelectric absorption due to a nonsolar relative abundance of neon, just as in the LETGS spectrum of 4U 0614+091. The optical properties of these systems suggest that all four are ultracompact (Porb < 80 minutes) binaries. We propose that there is excess neon local to each of these sources, as also found in the ultracompact binary pulsar 4U 1626-67. We suggest that the mass donor in these systems is a low-mass, neon-rich degenerate dwarf and that the binaries are all ultracompact.
Reduced models of networks of coupled enzymatic reactions

The Michaelis-Menten equation has played a central role in our understanding of biochemical processes. It has long been understood how this equation approximates the dynamics of irreversible enzymatic reactions. However, a similar approximation in the case of networks, where the product of one reaction can act as an enzyme in another, has not been fully developed. Here we rigorously derive such an approximation in a class of coupled enzymatic networks where the individual interactions are of Michaelis-Menten type. We show that the sufficient conditions for the validity of the total quasi-steady state assumption (tQSSA), obtained in a single protein case by Borghans, de Boer and Segel can be extended to sufficient conditions for the validity of the tQSSA in a large class of enzymatic networks. Secondly, we derive reduced equations that approximate the network's dynamics and involve only protein concentrations. This significantly reduces the number of equations necessary to model such systems. We prove the validity of this approximation using geometric singular perturbation theory and results about matrix differentiation. The ideas used in deriving the approximating equations are quite general, and can be used to systematize other model reductions.
feedback between population and evolutionary dynamics determines the fate of social microbial populations

The evolutionary spread of cheater strategies can destabilize populations engaging in social cooperative behaviors, thus demonstrating that evolutionary changes can have profound implications for population dynamics. At the same time, the relative fitness of cooperative traits often depends upon population density, thus leading to the potential for bi-directional coupling between population density and the evolution of a cooperative trait. Despite the potential importance of these eco-evolutionary feedback loops in social species, they have not yet been demonstrated experimentally and their ecological implications are poorly understood. Here, we demonstrate the presence of a strong feedback loop between population dynamics and the evolutionary dynamics of a social microbial gene, SUC2, in laboratory yeast populations whose cooperative growth is mediated by the SUC2 gene. We directly visualize eco-evolutionary trajectories of hundreds of populations over 50–100 generations, allowing us to characterize the phase space describing the interplay of evolution and ecology in this system. Small populations collapse despite continual evolution towards increased cooperative allele frequencies; large populations with a sufficient number of cooperators “spiral” to a stable state of coexistence between cooperator and cheater strategies. The presence of cheaters does not significantly affect the equilibrium population density, but it does reduce the resilience of the population as well as its ability to adapt to a rapidly deteriorating environment. Our results demonstrate the potential ecological importance of coupling between evolutionary dynamics and the population dynamics of cooperatively growing organisms, particularly in microbes. Our study suggests that this interaction may need to be considered in order to explain intraspecific variability in cooperative behaviors, and also that this feedback between evolution and ecology can critically affect the demographic fate of those species that rely on cooperation for their survival.
The Paley–Wiener Theorem and Limits of Symmetric Spaces

We extend the Paley–Wiener theorem for Riemannian symmetric spaces to an important class of infinite-dimensional symmetric spaces. For this we define a notion of propagation of symmetric spaces and examine the direct (injective) limit symmetric spaces defined by propagation. This relies on some of our earlier work on invariant differential operators and the action of Weyl group invariant polynomials under restriction.
Signatures of photon localization

Signatures of photon localization are observed in a constellation of transport phenomena which reflect the transition from diffusive to localized waves. The dimensionless conductance, g, and the ratio of the typical spectral width and spacing of quasimodes, δ, are key indicators of electronic and classical wave localization when inelastic processes are absent. However, these can no longer serve as localization parameters in absorbing samples since the effect of absorption depends upon the length of the trajectories of partial waves traversing the sample, which are superposed to create the scattered field. A robust determination of localization in the presence of absorption is found, however, in steady-state measurements of the statistics of radiation transmitted through random samples. This is captured in a single parameter, the variance of the total transmission normalized to its ensemble average value, which is equal to the degree of intensity correlation of the transmitted wave, κ. The intertwined effects of localization and absorption can also be disentangled in the time domain since all waves emerging from the sample at a fixed time delay from an exciting pulse, t, are suppressed equally by absorption. As a result, the relative weights of partial waves emerging from the sample, and hence the statistics of intensity fluctuations and correlation, and the suppression of propagation by weak localization are not changed by absorption, and manifest the growing impact of weak localization with t.
Enantioselective iridium-catalyzed carbonyl allylation from the alcohol or aldehyde oxidation level using allyl acetate as an allyl metal surrogate.

Protocols for highly enantioselective carbonyl allylation from the alcohol or aldehyde oxidation level are described based upon transfer hydrogenative C−C coupling. Exposure of allyl acetate to benzylic alcohols 1a−i in the presence of an iridium catalyst derived from [IrCl(cod)]2 and (R)-BINAP delivers products of C-allylation 2a−i. Employing isopropanol as terminal reductant, exposure of allyl acetate to aryl aldehydes 3a−i in the presence of an iridium catalyst derived from [IrCl(cod)]2 and (−)-TMBTP delivers identical products of C-allylation 2a−i. In all cases examined, exception levels of enantioselectivity are observed. Thus, enantioselective carbonyl allylation is achieved from the alcohol or aldehyde oxidation level in the absence of any preformed allylmetal reagents. These studies define a departure from preformed organometallic reagents in carbonyl additions that transcend the boundaries of oxidation level.
An acid-catalyzed formal allylic C-H oxidation of aryl cycloalkenes with N-propylthiosuccinimide.

A mild acid-catalyzed formal allylic C−H oxidation of aryl cycloalkenes with N-propylthiosuccinimide in the presence of various nucleophiles to generate allylic ethers, esters, and sulfonamides is described. A possible reaction mechanism has been proposed.
Multivariate and multiscale dependence in the global climate system revealed through complex networks

A systematic characterization of multivariate dependence at multiple spatio-temporal scales is critical to understanding climate system dynamics and improving predictive ability from models and data. However, dependence structures in climate are complex due to nonlinear dynamical generating processes, long-range spatial and long-memory temporal relationships, as well as low-frequency variability. Here we utilize complex networks to explore dependence in climate data. Specifically, networks constructed from reanalysis-based atmospheric variables over oceans and partitioned with community detection methods demonstrate the potential to capture regional and global dependence structures within and among climate variables. Proximity-based dependence as well as long-range spatial relationships are examined along with their evolution over time, yielding new insights on ocean meteorology. The tools are implicitly validated by confirming conceptual understanding about aggregate correlations and teleconnections. Our results also suggest a close similarity of observed dependence patterns in relative humidity and horizontal wind speed over oceans. In addition, updraft velocity, which relates to convective activity over the oceans, exhibits short spatiotemporal decorrelation scales but long-range dependence over time. The multivariate and multi-scale dependence patterns broadly persist over multiple time windows. Our findings motivate further investigations of dependence structures among observations, reanalysis and model-simulated data to enhance process understanding, assess model reliability and improve regional climate predictions.
Suppression of the shear viscosity in a 'semi'-quark-gluon plasma

We consider QCD at temperatures $T$ near ${T}_{c}$, where the theory deconfines. We distinguish between a ``complete'' quark-gluon plasma (QGP), where the vacuum expectation value of the renormalized Polyakov loop is near unity, essentially constant with $T$, and the ``semi''-QGP, where the loop changes strongly with $T$. Lattice simulations indicate that in QCD, there is a semi-QGP from below ${T}_{c}$ to a few times that. Using a semiclassical model, we compute the shear viscosity, $\ensuremath{\eta}$, to leading order in perturbation theory. We find that near ${T}_{c}$, where the expectation value of the Polyakov loop is small, that $\ensuremath{\eta}/{T}^{3}$ is suppressed by two powers of the loop. For heavy ions, this suggests that during the initial stages of the collision, hydrodynamic behavior at the LHC will be characterized by a shear viscosity which is significantly larger than that at RHIC.
An example of an infinite dimensional filtering problem: Filtering for gyroscopic noise

An infinite-dimensional model is given for the generation of gyroscopic noise, which exhibits power spectral density proportional to (1/f) over a wide frequency range. The optimal filter is given for separating a statistically described signal form additive gyroscopic noise, using discrete-time observations. This filter is expressed as a discrete-time infinite-dimensional Kalman-Bucy filter, with an associated Riccati covariance operator equation. Sufficient conditions are specified such that this Kalman-Bucy filter will possess various desired properties.
Fixing all moduli in a simple f-theory compactification

We discuss a simple example of an F-theory compactification on a Calabi-Yau fourfold where background fluxes, together with nonperturbative effects from Euclidean D3 instantons and gauge dynamics on D7 branes, allow us to fix all closed and open string moduli. We explicitly check that the known higher order corrections to the potential, which we neglect in our leading approximation, only shift the results by a small amount. In our exploration of the model, we encounter interesting new phenomena, including examples of transitions where D7 branes absorb O3 planes, while changing topology to preserve the net D3 charge.
A unified approach to deterministic and random errors in hybrid loops

Hybrid computation in general owes its growing acceptance to the increasing number of sophisticated problems that neither digital nor analog computers alone can handle adequately. In most cases this apparently cumbersome approach is justified by the speed of analog computers, a speed impossible to attain in all-digital systems, even where the problem requires the memory and logic capabilities that only digital computers can provide.
An intramolecular [8+6] cycloaddition

Abstract An intramolecular [8+6] cycloaddition of a heptafulvene linked to a fulvene by a trimethylene chain has been observed.
Same Coin, Different Sides: Differential Impact of Social Learning on Two Facets of Music Piracy

We demonstrate that two intertwined activities of music piracy, unauthorized obtaining and unauthorized sharing, are differentially influenced by the same social learning environment. We develop a structural model and test it using survey data from a prime demographic set of respondents who engage in music piracy. Considering behavioral heterogeneity, we employ a factor mixture modeling technique to classify respondents into different groups that highlight distinct patterns of social learning influences. We find that the differential effects of social learning factors on obtaining and sharing persist across these groups. We further utilize demographic variables to profile members in each group for segmentation insights. From a theoretical perspective, our findings advance the understanding of music piracy and suggest the importance of separating obtaining from sharing activities when studying piracy. From a managerial perspective, our research provides new avenues for managers and policymakers to design targeted incentives to curtail music piracy.
A Near-infrared Spectroscopic Study of Young Field Ultracool Dwarfs

We present a near-infrared (0.9-2.4 μm) spectroscopic study of 73 field ultracool dwarfs having spectroscopic and/or kinematic evidence of youth (10-300 Myr). Our sample is composed of 48 low-resolution (R 100) spectra and 41 moderate-resolution spectra (R 750-2000). First, we establish a method for spectral typing M5-L7 dwarfs at near-IR wavelengths that is independent of gravity. We find that both visual and index-based classification in the near-IR provides consistent spectral types with optical spectral types, though with a small systematic offset in the case of visual classification at J and K band. Second, we examine features in the spectra of ~10 Myr ultracool dwarfs to define a set of gravity-sensitive indices based on FeH, VO, K I, Na I, and H-band continuum shape. We then create an index-based method for classifying the gravities of M6-L5 dwarfs that provides consistent results with gravity classifications from optical spectroscopy. Our index-based classification can distinguish between young and dusty objects. Guided by the resulting classifications, we propose a set of low-gravity spectral standards for the near-IR. Finally, we estimate the ages corresponding to our gravity classifications.
Numerical Simulation of Vortex-Induced Oblique Shock-Wave Distortion

We simulate oblique shock-wave/wing-tip vortex interactions via solution to the compressible three-dimensional mass-averaged turbulent Navier-Stokes equations. A two-equation (k-e) turbulence model is employed that includes low-Reynolds terms and a compressibility correction.
Stellar Content of Galaxies

Two parameters which describe the stars that make up any galaxy are age and chemical composition.
Benefits of Active Compressor Stability Management on Turbofan Engine Operability

Active compressor stability management can play a significant role in the intelligent control of gas turbine engines. The present work utilizes a computer simulation to illustrate the potential operability benefits of compressor stability management when actively controlling a turbofan engine. The simulation, called the modular aeropropulsion system simulation (MAPSS) and developed at NASA Glenn, models the actuation, sensor, controller, and engine dynamics of a twin-spool, low-bypass turbofan engine. The stability management system is built around a previously developed stability measure called the correlation measure. The correlation measure quantifies the repeatability of the pressure signature of a compressor rotor. Earlier work has used laboratory compressor and engine rig data to develop a relationship between a compressor's stability boundary and its correlation measure. Specifically, correlation measure threshold crossing events increase in magnitude and number as the compressor approaches the limit of stable operation. To simulate the experimentally observed behavior of these events, a stochastic model based on level-crossings of an exponentially distributed pseudorandom process has been implemented in the MAPSS environment. Three different methods of integrating active stability management within the existing engine control architecture have been explored. The results show that significant improvements in the engine emergency response can be obtained while maintaining instability-free compressor operation via any of the methods studied. Two of the active control schemes investigated utilize existing scheduler and controller parameters and require minimal additional control logic for implementation. The third method, while introducing additional logic, emphasizes the need for as well as the benefits of a more integrated stability management system.
Application and performance of magnetic-core circuits in computing systems

The magnetic cores developed prior to 1952 were nonuniform and, therefore, extremely marginal in their operating characteristics. Not only did they present many circuit problems but they were difficult to manufacture as well. Since 1952, however, the picture has changed radically; rapid development of core materials, more advanced processing techniques, as well as new circuits and design techniques have all combined to place the magnetic core in a position equal to, if not superior to, all other digital components. Today this increased tempo in development is becoming evident in many laboratories and the number of new systems and components that employ magnetic cores is increasing rapidly. In fact, it is quite safe to predict that most computers designed in 1955 will use more magnetic cores than any other 2-state component. The promise of unusual reliability and long life of the magnetic core has been the motivating factor in most of the developments. Then, too, the possibility of reduction in cost, weight, and power requirements has its measure of attraction.
On Rubin’s variant of the p-adic Birch and Swinnerton–Dyer conjecture II

Let E/Q be an elliptic curve with complex multiplication by the ring of integers of an imaginary quadratic field K. In 1991, by studying a certain special value of the Katz two-variable p-adic L-function lying outside the range of p-adic interpolation, K. Rubin formulated a p-adic variant of the Birch and Swinnerton–Dyer conjecture when E(K) is infinite, and he proved that his conjecture is true for E(K) of rank one. When E(K) is finite, however, the statement of Rubin’s original conjecture no longer applies, and the relevant special value of the appropriate p-adic L-function is equal to zero. In this paper we extend our earlier work and give an unconditional proof of an analogue of Rubin’s conjecture when E(K) is finite.
EXPOSED: VENTURE CAPITAL, COMPETITOR TIES, AND ENTREPRENEURIAL INNOVATION

This study investigates the impact of early relationships on innovation at entrepreneurial firms. Prior research has largely focused on the benefits of network ties, documenting the many advantages that accrue to firms embedded in a rich network of interorganizational relationships. In contrast, we build on research emphasizing potential drawbacks to examine how competitive exposure, enabled by powerful intermediaries, can inhibit innovation. We develop the concept of "competitive information leakage," which occurs when firms are indirectly tied to their competitors via shared intermediary organizations. To test our theory, we examine every relationship between entrepreneurial firms and their venture capital investors in the minimally invasive surgical device segment of the medical device industry over a 22-year period. We find that indirect ties to competitors impede innovation, and that this effect is moderated by several factors related to the intermediary's opportunities and motivation to leak important information