cssi/SciSciGPT-SciSciNet huggingface dataset:
Skill bias, trade, and wage dispersion ☆

Abstract Wage ratios between different percentiles of the wage distribution have moved in parallel and then diverged in the U.S. in the last 50 years. In this paper, I study the theoretical response of wage ratios to skill-biased technical change and trade integration. I build a simple model of heterogeneous technology and heterogeneous workers that features complementarities between the quality of ideas and abilities. I show that changes to the skill bias of technology and to trade costs can both reproduce the observed pattern since (i) they have similar asymmetric effects on productive vs. unproductive firms, and (ii) positive assortative matching in the labor market transmits this asymmetry across high and low skill workers. Focusing on the different channels through which skill-biased technical change and trade integration operate suggests ways to disentangle the magnitude of each.
Spontaneous Stochasticity and Anomalous Dissipation for Burgers Equation

We develop a Lagrangian approach to conservation-law anomalies in weak solutions of inviscid Burgers equation, motivated by previous work on the Kraichnan model of turbulent scalar advection. We show that the entropy solutions of Burgers possess Markov stochastic processes of (generalized) Lagrangian trajectories backward in time for which the Burgers velocity is a backward martingale. This property is shown to guarantee dissipativity of conservation-law anomalies for general convex functions of the velocity. The backward stochastic Burgers flows with these properties are not unique, however. We construct infinitely many such stochastic flows, both by a geometric construction and by the zero-noise limit of the Constantin–Iyer stochastic representation of viscous Burgers solutions. The latter proof yields the spontaneous stochasticity of Lagrangian trajectories backward in time for Burgers, at unit Prandtl number. It is conjectured that existence of a backward stochastic flow with the velocity as martingale is an admissibility condition which selects the unique entropy solution for Burgers. We also study linear transport of passive densities and scalars by inviscid Burgers flows. We show that shock solutions of Burgers exhibit spontaneous stochasticity backward in time for all finite Prandtl numbers, implying conservation-law anomalies for linear transport. We discuss the relation of our results for Burgers with incompressible Navier–Stokes turbulence, especially Lagrangian admissibility conditions for Euler solutions and the relation between turbulent cascade directions and time-asymmetry of Lagrangian stochasticity.
Diplomatic imaginations: mediating estrangement in world society

This article is an inquiry into the relationship between diplomacy and public imagination in world politics. Neither the conventional conceptions of diplomacy as the art or practice of negotiations among groups or states, nor more critical meditations on the mediation of conflictual narratives, it is argued, can adequately explain the very subjective foundations of diplomacy as a normative practice in world politics. This glaring oversight is in large part due to the lack of engagement with the varied contours of historical meaning and memory that condition human thoughts and relations in world society. Diplomacy, I argue, is very much implicated in the normative dictates of public imagination: namely, the public understanding of history which arises from the exclusionary—and hence often conflicting—cultural narratives about nationhood, justice, language, rights, personhood, et cetera that remain the perennial facts of human relations in world society. As such, the practice of diplomacy can be reconceived...
What a Difference One Electron Makes! Generating Low-Coordinate Ti–C and V–C Multiply Bonded Frameworks through One Electron Oxidatively Induced α-Hydrogen Abstractions

Low-coordinate, high oxidation state titanium and vanadium complexes containing terminal metal–carbon multiply bonded functionalities have been prepared directly or indirectly through one electron oxidatively induced α-hydrogen abstraction reactions. This synthetic approach offers a mild entry to reactive M=C and M≡C motifs, and does not depend on external stimulants such as heat, light or base to promote the α-hydrogen-abstraction step. In addition, this strategic protocol avoids the use of powerful electrophiles, thus generating terminal and nucleophilic M–C multiple bonds in low-coordination environments. In some cases terminal alkylidenes containing β-hydrogen atoms can also be introduced through this route. This microreview surveys the synthesis and chemistry surrounding isolable titanium and vanadium complexes bearing terminal alkylidene and alkylidyne ligands. Particular emphasis will be placed on the synthesis of the high oxidation state M–C multiple bond. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Sensitivity to soil moisture by active and passive microwave sensors

The backscatter measured by radar and the emission measured by a radiometer are both very sensitive to the moisture content m/sub /spl upsi// of bare-soil surfaces. Vegetation cover complicates the scattering and emission processes, and it has been presumed that the addition of vegetation masks the soil surface, thereby reducing the radiometric and radar soil-moisture sensitivities. Even though researchers working in the field of microwave remote sensing of soil moisture are all likely to agree with the preceding two statements, numerous claims and counterclaims have been voiced, primarily at symposia and workshops, espousing the superiority of the radiometric technique over the radar, or vice versa. The discussion is often reduced to disagreements over the answer to the following question "Which of the two sensing techniques is less impacted by vegetation cover?" This paper is an attempt to answer that question. Using realistic radiative-transfer models for the emission and backscatter, calculations were performed for three types of canopies, all at 1.5 GHz. The results lead to two major conclusions. First, the accepted presumption that vegetation cover reduces the soil-moisture sensitivity is not always true. Over certain ranges of the optical depth /spl tau/ of the vegetation canopy and the roughness of the soil surface, vegetation cover can enhance, not reduce, the radar sensitivity to soil moisture. The second conclusion is that under most vegetation and soil-surface conditions, the radiometric and radar soil-moisture sensitivities decrease with increasing /spl tau/, and the rates are approximately the same for both sensors, suggesting that at least as far as vegetation effects are concerned, neither sensor can claim superiority over the other.
Dynamics of obsidian flows inferred from microstructures: insights from microlite preferred orientations

The flow of obsidian lava leads to crystal alignments that reflect both the accumulated strain and the type of flow across the surface. Microlite preferred orientations are used to investigate the emplacement dynamics, strain history, and structural evolution of Obsidian Dome, eastern California. Measurements of three-dimensional microlite trend and plunge in samples from the near-vent region, distal flow, and flow front show: (1) the flow directions along the dome margins, (2) the deformation style (e.g., pure versus simple shear) at the dome margins, and (3) the variation in strain as a function of position within the flow. Microlites form well-developed lineations in the plane of flow banding in all samples. Stereographic projections indicate that lineations trend normal to the western flow front and plunge shallowly away from the margin. The radial flow pattern indicated by measurements made along the western margin suggests that extrusion was from a roughly elliptical vent. These results highlight a strong correlation between microlite trend and the bulk flow direction inferred from the geometry of the flow. Along most of the eastern periphery, lineations trend parallel to the margin and likely reflect the local flow direction as influenced by compression against the thickening flow crust, marginal talus piles, and topography. Orientation distributions imply that radial spreading accompanied by flattening was the dominant mechanism for flow emplacement. Comparisons of measured orientation distributions with theoretical predictions suggest that microlite fabrics in flow front and nearvent samples developed in a pure shear flow. Microstructures in a sample from near the distal flow base records a component of simple shear. Variance in microlite trend provides a measure of the amount of strain acquired during flow. Standard deviation in trend decreases from the near-vent region to the flow margins, reflecting progressive alignment of microlites during transport. Pure shear strain inferred from orientation distributions increases from approximately 0.3 near the vent to about 1.1 at the flow front. The difference between these strains (0.8) is an estimate of the strain associated with flow emplacement. Such strain is similar in size to that estimated from mesoscopic structures (V1) and for horizontal spreading of a fluid whose volume is equal to that of Obsidian Dome (V1.6). This suggests that flow on the surface was sufficient to produce observed microlite preferred orientations in the flow front. These techniques can be applied to interpret older dissected lavas where erosion has erased much of the original flow front or where larger-scale structures indicative of flow directions are poorly preserved. fl 2002 Elsevier Science B.V. All rights reserved.
Elliptic Curves of Large Rank and Small Conductor

For r=6,7,...,11 we find an elliptic curve E/Q of rank at least r and the smallest conductor known, improving on the previous records by factors ranging from 1.0136 (for r=6) to over 100 (for r=10 and r=11). We describe our search methods, and tabulate, for each r=5,6,...,11, the five curves of lowest conductor, and (except for r=11) also the five of lowest absolute discriminant, that we found.
Carbon Additions to Molybdenum Disilicide: Improved High‐Temperature Mechanical Properties

C addition (2 wt%) to MoSi2 acted as a deoxidant, removing the otherwise ubiquitous siliceous grain boundary phase in hot-pressed samples, and causing formation of SiC and Mo5Si3C1 (a variable-composition Nowotny phase). Both hardness and fracture toughness of the C-containing alloy were higher than those of the C-free (and oxygen-rich) material; more significantly, the fracture toughness of the MoSi2+ 2% C alloy increased from 5.5 MPa·m1/2 at 800°C to ∼11.5 MPa·m1/2 at 1400°C.
Comparison of a global-climate model to a cloud-system resolving model for the long-term response of thin stratocumulus clouds to preindustrial and present-day aerosol conditions

Abstract. The response of a case of thin, warm marine-boundary-layer (MBL) clouds to preindustrial (PI) and present-day (PD) conditions is simulated by a cloud-system resolving model (CSRM). Here, both the aerosol conditions and environmental conditions match those of a general circulation model (GCM). The environmental conditions are characterized by the initial condition and the large-scale forcings of humidity and temperature, as well as the surface fluxes. The response of the CSRM is compared to that simulated by the GCM. The percentage increase of liquid-water path (LWP) due to a change from the PI to PD conditions is ~3 times larger in the CSRM than that in the GCM due to the formation of cumulus clouds. The formation of cumulus clouds is controlled by a larger increase in the surface latent-heat (LH) flux in the PD environment than in the PI environment rather than by the change in aerosols. However, the aerosol increase from the PI to PD level determines the LWP response in the stratocumulus clouds, while the impacts of changes in environmental conditions are negligible for stratocumulus clouds. The conversion of cloud liquid to rain through autoconversion and accretion plays a negligible role in the CSRM in the response to aerosols, whereas it plays a role that is as important as condensation in the GCM. Also, it is notable that the explicit simulation of microphysics in the CSRM leads to a smaller LWP in the CSRM than that in the GCM using heavily parameterized microphysics for stratocumulus clouds. The smaller LWP in the CSRM is closer to an observed LWP than the LWP in the GCM for stratocumulus clouds. Supplementary simulations show that increasing aerosols increase the sensitivity of the cloud responses to the PI and PD environmental conditions. They also show that aerosol effects on clouds depend on the cloud type. The LWP of warm cumulus clouds is more sensitive to aerosols than that of stratocumulus clouds.
Sampling and aliasing consequences of quarter-detector offset use in helical CT

In this paper, the sampling and aliasing consequences of employing a quarter-detector-offset (QDO) in helical computed tomography (CT) are analyzed. QDO is often used in conventional CT to reduce in-plane aliasing by eliminating data redundancies to improve radial sampling. In helical CT, these same redundancies are exploited to improve longitudinal sampling and so it might seem ill-advised to employ QDO. The relative merit of the two geometries for helical CT is studied by conducting a multidimensional sampling analysis of projection-space sampling as well as a Fourier crosstalk analysis of crosstalk among the object's Fourier basis components. Both a standard fanbeam helical CT geometry and a hypothetical parallel-beam CT geometry, which helps illuminate the more complicated fanbeam results, are analyzed. Using the sampling analysis, it was found that the use of QDO leads to very different spectral tiling than arise when not using QDO. However, due to the shape of the essential support of the projection data spectra that arises in practice, both configurations lead to very similar or identical amounts of spectral overlap. This perspective also predicts the spatially variant longitudinal aliasing that has been observed in helical CT. The crosstalk results were consistent with those of the multidimensional sampling analysis. Thus, from the standpoint of aliasing and crosstalk, no compelling difference is found between the two geometries.
String stability of interconnected systems

Introduces the notion of string stability of a countably infinite interconnection of a class of nonlinear systems. Intuitively, string stability implies uniform boundedness of all the states of the interconnected system for all time if the initial states of the interconnected system are uniformly bounded. It is well known that the input output gain of all the subsystems less than unity guarantees that the interconnected system is input-output stable. The authors derive sufficient ("weak coupling") conditions which guarantee the asymptotic string stability of a class of interconnected systems. Under the same "weak coupling" conditions, string-stable interconnected systems remain string stable in the presence of small structural/singular perturbations. In the presence of parameter mismatch, these "weak coupling" conditions ensure that the states of all the subsystems are all uniformly bounded when a gradient-based parameter adaptation law is used and that the states of all the systems go to zero asymptotically.
Principles of Artificial Intelligence

A classic introduction to artificial intelligence intended to bridge the gap between theory and practice, "Principles of Artificial Intelligence" describes fundamental AI ideas that underlie applications such as natural language processing, automatic programming, robotics, machine vision, automatic theorem proving, and intelligent data retrieval. Rather than focusing on the subject matter of the applications, the book is organized around general computational concepts involving the kinds of data structures used, the types of operations performed on the data structures, and the properties of the control strategies used. "Principles of Artificial Intelligence"evolved from the author's courses and seminars at Stanford University and University of Massachusetts, Amherst, and is suitable for text use in a senior or graduate AI course, or for individual study.
Dilated matrix inequalities for control design in systems with actuator constraint

In this paper, we present a new variation of dilated matrix inequalities (Mis) for Bounded Real MI, invariant set MI and constraint MI, for both state and output feedback synthesis problems. In these dilated MIs, system matrices are separated from Lyapunov matrices to allow the use of different Lyapunov matrices in multi-objective and robust problems. To demonstrate the benefit of these new dilated MIs over conventional ones, they are used in solving controller synthesis problem for systems with bounded actuator in disturbance attenuation. It is shown that for the resulting multi-objective saturation problem, the new form of dilated MIs achieves an upper bound for L2 gain that is less than or equal to the upper bound estimate achieved by conventional method.
New mechanisms centered on reactive intermediates: Examples from diazirine and carbene chemistry

Laser flash photolysis (LFP) of appropriate diazirine precursors afforded the UV spectra of methylchlorocarbene, benzylchlorocarbene, cyclopropylchlorocarbene, and 1-adamantylchlorocarbene. The σ→ p transitions of these carbenes were used to directly monitor their reaction kinetics. The unusual and highly reactive N 2 CO compound, diaziri- none, was obtained from the reaction of fluoride ion with p-nitrophenoxychlorodiazirine. Diazirinone fragmented to CO and N 2 in a reaction that was exothermic by >90 kcal/mol. Dichlorodiazirine (DCD) was generated by the reaction of chloride ion with p-nitro- phenoxychlorodiazirine. Reactions of dichlorocarbene generated from DCD are discussed.
The Global Decline of the Labor Share

The stability of the labor share of income is a key foundation in macroeconomic models. We document, however, that the global labor share has signicantly declined since the early 1980s, with the decline occurring within the large majority of countries and industries. We show that the decrease in the relative price of investment goods, often attributed to advances in information technology and the computer age, induced rms
Genetic algorithms approach for the assessment of composite power system reliability considering multistate components

This paper introduces a genetic algorithms (GA) based approach for the assessment of composite power system reliability. This enhanced approach recognizes multistate components such as generation units with derated states. It also considers common mode failure for transmission lines. Binary encoded GA is used as a state sampling tool for the composite power system network states. Both annual and annualized adequacy indices are calculated. The superiority of the proposed approach over other conventional methods comes from the ability of GA to trace failure states in an intelligent, controlled and prespecified manner through the selection of a suitable fitness function. Case studies on a sample test system considering chronological load curves, derated states and common mode failures are presented. Results are analyzed to determine the effect of considering multistate components
Persuasion: Empirical Evidence

We provide a selective survey of empirical evidence on the effects as well as the drivers of persuasive communication. We consider persuasion directed at consumers, voters, donors, and investors. We organize our review around four questions. First, to what extent does persuasion affect the behavior of each of these groups? Second, what models best capture the response to persuasive communication? Third, what are persuaders' incentives, and what limits their ability to distort communications? Finally, what evidence exists on the way persuasion affects equilibrium outcomes in economics and politics?
SAS+ planning as satisfiability

Planning as satisfiability is a principal approach to planning with many eminent advantages. The existing planning as satisfiability techniques usually use encodings compiled from STRIPS. We introduce a novel SAT encoding scheme (SASE) based on the SAS+ formalism. The new scheme exploits the structural information in SAS+, resulting in an encoding that is both more compact and efficient for planning. We prove the correctness of the new encoding by establishing an isomorphism between the solution plans of SASE and that of STRIPS based encodings. We further analyze the transition variables newly introduced in SASE to explain why it accommodates modern SAT solving algorithms and improves performance. We give empirical statistical results to support our analysis. We also develop a number of techniques to further reduce the encoding size of SASE, and conduct experimental studies to show the strength of each individual technique. Finally, we report extensive experimental results to demonstrate significant improvements of SASE over the state-of-the-art STRIPS based encoding schemes in terms of both time and memory efficiency.
3-Indolyl-1-naphthylmethanes: New Cannabimimetic Indoles. Provide Evidence for Aromatic Stacking Interactions with the. CB1 Cannabinoid Receptor

A series of 1-pentyl-1H-indol-3-yl-(1-naphthyl)methanes (9-11) and 2-methyl-1-pentyl-1H-indol-3-yl-(1-naphthyl)methanes (12-14) have been synthesized to investigate the hypothesis that cannabimimetic 3-(1-naphthoyl)indoles interact with the CB(1) receptor by hydrogen bonding to the carbonyl group. Indoles 9-11 have significant (K(i)=17-23nM) receptor affinity, somewhat less than that of the corresponding naphthoylindoles (5, 15, 16). 2-Methyl-1-indoles 12-14 have little affinity for the CB(1) receptor, in contrast to 2-methyl-3-(1-naphthoyl)indoles 17-19, which have affinities comparable to those of 5, 15, 16. A cannabimimetic indene hydrocarbon (26) was synthesized and found to have K(i)=26+/-4nM. Molecular modeling and receptor docking studies of naphthoylindole 16, its 2-methyl congener (19) and indolyl-1-naphthylmethanes 11 and 14, combined with the receptor affinities of these cannabimimetic indoles, strongly suggest that these cannabinoid receptor ligands bind primarily by aromatic stacking interactions in the transmembrane helix 3-4-5-6 region of the CB(1) receptor.
Elasticity, fracture and thermoreversible gelation of highly filled physical gels.

We describe a physically associating triblock copolymer-based gel that exhibits a reversible transition between solid and liquid states at a temperature of approximately 55°C. The thermal transition of the gel enables us to compare the properties of liquid suspensions and elastic composites with identical particle loadings, with particle volume fractions as large as 0.55. The suspension viscosity and the composite elasticity scale in a similar manner with the overall particle volume fraction, a result that is rationalized in terms of an effective strain amplification factor that depends only on the particle loading. Measured values of the strain amplification factor are in good agreement with the expected form for well-dispersed spheres. We also find that the elastic composites are exceptionally strong, with fracture strengths that exceed the modulus of the base gel by a factor of 100 or more. Deviations from purely elastic behavior became important for high particle volume fractions, and were probed by stress relaxation experiments.
Scattering by many small inhomogeneities and applications

3rd Chaotic Modeling and Simulation International Conference. Chiana, Crete, Greece. June 1-4, 2010.
Facets of the QCD Phase-Diagram

In this contribution we will discuss two aspects of the matter created in ultra-relativistic heavy ion collisions. First we will attempt to define a universal measure for the fluidity of a substance, which will allow a correct comparison between the fluidity of a Quark Gluon Plasma and any well known substance. Second we will discuss current measurements of particle correlations and their implication for possible local parity violation.
Comparing the Earth Impact Flux from Comets and Near-Earth Asteroids

Abstract When compared to the discovered set of near-Earth asteroids, the Earth impact flux of all known active comets, including Jupiter family comets, Halley-type and long period comets, is below 1%. However, the comet impact fluxes may be higher for those objects large enough to cause extinction level events.
The Economics of Buyer Uncertainty: Advance Selling vs. Probabilistic Selling

Although advance selling and probabilistic selling differ in both motivation and implementation, we argue that they share a common characteristic---both offer consumers a choice involving buyer uncertainty. We develop a formal model to examine the general economics of purchase options that involve buyer uncertainty, explore the differences in buyer uncertainty created via these two strategies, and derive conditions under which one dominates the other. We show that the seller can address unobservable buyer heterogeneity by inducing sales involving buyer uncertainty via two different mechanisms: (1) homogenizing heterogeneous consumers and (2) separating heterogeneous consumers. Offering advance sales encourages customers to purchase while they are uncertain about their consumption states (more homogeneous), but offering probabilistic goods encourages customers to reveal their heterogeneity via self-selecting whether or not to purchase the uncertain product. The relative attractiveness of these two selling strategies depends on the degree of two types of buyer heterogeneity: (1) Max_Value-Heterogeneity, which is the variation in consumers' valuations for their preferred good, and (2) Strength-Heterogeneity, which is the variation in the strength of consumers' preferences. Neither strategy is advantageous unless the market exhibits sufficient Max_Value-Heterogeneity. However, whereas Strength-Heterogeneity can destroy the profit advantage of advance selling, a mid-range of Strength-Heterogeneity is necessary for probabilistic selling to be advantageous.
Consensus in the two-state Axelrod model

Abstract The Axelrod model is a spatial stochastic model for the dynamics of cultures which, similar to the voter model, includes social influence, but differs from the latter by also accounting for another social factor called homophily, the tendency to interact more frequently with individuals who are more similar. Each individual is characterized by its opinions about a finite number of cultural features, each of which can assume the same finite number of states. Pairs of adjacent individuals interact at a rate equal to the fraction of features they have in common, thus modeling homophily, which results in the interacting pair having one more cultural feature in common, thus modeling social influence. It has been conjectured based on numerical simulations that the one-dimensional Axelrod model clusters when the number of features exceeds the number of states per feature. In this article, we prove this conjecture for the two-state model with an arbitrary number of features.
An efficient distributed synchronization method for TD/CDMA based Mobile Ad Hoc Networks

Mobile Ad Hoc Network (MANET) and Sensor Networks have no fixed infrastructures such as Base Stations and Towers, and have limited bandwidth across the network elements. They use multi-hop radio communications to deliver multi-service (voice, data, and video) information. Each network element can either send a packet or receive a packet but not both. Therefore, synchronization between radios must be achieved for every packet scheduling time with minimal amount of time to ensure QoS provisioning. This paper presents a novel distributed synchronization scheme for radio communication in a TD/CDMA based MANET and Sensor Networks. The scheme is designed using a first order Digital Phase locked loop (DPLL) which performs the ‘local locking’ at each receiver radio in a cluster of radios. The method exploits the clock drifts in each local clock of a radio with reference to which the local stored clocks are phase adjusted within the loop of the DPLL. A parameter called ‘phase adjustment index’ represented by ‘N’- an integer; is defined and is used as the scaling value of the local clock frequency. Analytical results have been shown to yield an effectively reduced size of overhead when compared to the overhead sizes dedicated for synchronization purpose in IEEE 802.11. The results have been verified by simulation in MATLAB.
Linear maps preserving invariants

[Dix79] J. Dixmier, Champs de vecteurs adjoints sur les groupes et alg`ebres de Lie semi-simples, J. ReineAngew. Math. 309 (1979), 183–190.[Hum72] J.E. Humphreys, Introduction to Lie Algebras and Representation Theory, Graduate Texts in Math-ematics 9, Springer-Verlag, New York, 1972.[Jac62] N. Jacobson, Lie algebras, Interscience Publishers, New York, 1962.
System Parameters of the Transiting Extrasolar Planet HD 209458b

We derive improved system parameters for the HD 209458 system using a model that simultaneously fits both photometric transit and radial velocity observations. The photometry consists of previous Hubble Space Telescope STIS and FGS observations, 12 I-band transits observed between 2001 and 2003 with the Mount Laguna Obser- vatory 1 m telescope, and six Stromgrenb þ y transits observed between 2001 and 2004 with two of the Automatic Photometric Telescopes at Fairborn Observatory. The radial velocities were derived from Keck HIRES observations. The model properly treats the orbital dynamics of the system and thus yields robust and physically self-consistent solutions. Our set of system parameters agrees with previously published results, although with improved ac- curacy. For example, applying robust limits on the stellar mass of 0.93-1.20 M� ,w e fi nd 1:26RJ < Rplanet < 1:42RJ and 0:59MJ < Mplanet < 0:70MJ. We can reduce the uncertainty of these estimates by including a stel- lar mass-radius relation constraint, yielding Rplanet ¼ 1:35 � 0:07 ðÞ RJ and Mplanet ¼ 0:66 � 0:04
A model for multilevel security in computer networks

A model is presented that precisely describes the mechanism that enforces the security policy and requirements for a multilevel secure network. The mechanism attempts to ensure secure flow of information between entities assigned to different security classes in different computer systems connected to the network. The mechanism also controls the access to the network devices by the subjects (users and processes executed on behalf of the users) with different security clearances. The model integrates the notions of nondiscretionary access control and information flow control to provide a trusted network base that imposes appropriate restrictions on the flow of information among the various devices. Utilizing simple set-theoretic concepts, a procedure is given to verify the security of a network that implements the model. >
The Pricing of Lake Lots

This article reveals aspects of lakefront property pricing especially with respect to lot frontage and depth. A clearer understanding of how these lot dimensions affect price should be of interest to those engaged in lake development, land use control, valuation, and marketing. A data set with eighty observations of vacant Lake Michigan residential properties sales is used. The unique geography of northwest Michigan provides an opportunity to tackle empirical issues associated with zoning when zoning is correlated with lot attributes, such as lot topography.
Ceiling Jet-Driven Wall Flows in Compartment Fires

Abstract Analytic estimates are developed for depth of penetration and lateral entrainment of negatively buoyant, ceiling jet-driven wall flows during early times of compartment fire scenarios. When walls are not too far from the fire source of the order of the fire-to-ceiling distance, it is found that the penetration of these downward wall flows is a large fraction of the fire-to-ceiling distance, and that this Traction is relatively independent of the details of fire size and fire-to-wall spacing. Also, net rate of entrainment into the wall flow as it is buoyed back upward to the ceiling elevation is found to be several times larger than the Row rate of the driving ceiling jet flow immediately upstream of wall impingement. Data from five studies reported in the literature are reviewed relative to the analytic results obtained. One of these involved a field model simulation of the flow generated by a buoyant source in an enclosure. Two experimental laboratory studies involved fires in enclosures with ch...
Adaptive cascaded beam-based feedback at the SLC

The SLAC Linear Collider now has a total of twenty-four beam-steering feedback loops used to keep the electron and positron beams on their desired trajectories. Seven of these loops measure and control the same beam as it proceeds down the linac through the arcs to the final focus. Ideally each loop should correct only for disturbances that occur between it and the immediate upstream loop. In fact, in the original system each loop corrected for all upstream disturbances. This resulted in undesirable overcorrection and ringing. We added MIMO (Multiple Input Multiple Output) adaptive noise cancellers to separate the signal we wish to correct from disturbances further up stream. This adaptive control improved performance in the 1992 run. >
Ru(II)-catalyzed ortho-C-H amination of arenes and heteroarenes at room temperature.

The Ru(II)-catalyzed ortho-C–H amination directed by a weakly coordinating amide auxiliary with O-benzoyl hydroxylamines at room temperature has been achieved. This reaction is compatible with heterocycles including pyrazole, thiophene, benzothiophene, furan, benzofuran, and indole.
Topological Electric Charge

By treating magnetic charge as a gauge symmetry through the introduction of a “magnetic” pseudo four-vector potential, we show that it is possible to construct a topological electric charge from a theory which originally contains gauge magnetic charge. This is an explicit realization of the Montonen-Olive conjecture that there should exist a dual theory to the usual 't Hooft-Polyakov monopole theory in which the roles of the gauge and topological charges are reversed. The physical distinction between 't Hooft-Polyakov monopoles and the dual theory with electric charge is that the strong and weak coupling regimes are reversed. Physically this leads to the mass of the electrically charged soliton being on the order of (1/137)MW as opposed to the much larger mass (on the order of 137MW) of the magnetically charged soliton. Thus even forMW in the TeV range such an electrically charged particle could be observed at some future accelerator.
Vitamin D deficiency in minority populations

ObjectiveBlack and Hispanic individuals synthesize less vitamin D per unit of sun exposure than white individuals. The relationship between UV radiation and vitamin D insufficiency in minorities has not been well explored.DesignProspective cohort study.SettingUsing the National Health and Nutrition Examination Survey, we obtained serum vitamin D levels for non-Hispanic Whites, Hispanics and non-Hispanic Blacks aged ≥18 years from 2000–2006. We linked these data with the average monthly solar UV index by census tract and data on sun exposure, vitamin D supplementation, health and demographics. We used multivariable regression analyses to assess vitamin D deficiency (<15 ng/ml) and insufficiency (<20 ng/ml) in January (when the UV index was lowest) by race/ethnicity and geography.SubjectsAdults (n 14 319) aged ≥18 years.ResultsA 1-point increase in the UV index was associated with a 0·51 ng/ml increase in vitamin D (95 % CI 0·35, 0·67 ng/ml; P<0·001). Non-Hispanic Black race and Hispanic ethnicity were associated with a 7·47 and 3·41 ng/ml decrease in vitamin D, respectively (both P<0·001). In January, an estimated 65·4 % of non-Hispanic Blacks were deficient in vitamin D, compared with 28·9 % of Hispanics and 14·0 % of non-Hispanic Whites. An estimated 84·2 % of non-Hispanic Blacks were insufficient in vitamin D v. 56·3 % of Hispanics and 34·8 % of non-Hispanic Whites. More non-Hispanic Blacks were estimated to be deficient in vitamin D in January in the highest UV index quartile than were non-Hispanic Whites in the lowest UV index quartile (60·2 % v. 25·7 %).ConclusionsWintertime vitamin D insufficiency is pervasive among minority populations, and not uncommon among non-Hispanic Whites.
How Does Free Riding on Customer Service Affect Competition

The free-riding problem occurs if the presales activities needed to sell a product can be conducted separately from the actual sale of the product. Intuitively, free riding should hurt the retailer that provides that service, but the author shows analytically that free riding benefits not only the free-riding retailer, but also the retailer that provides the service when customers are heterogeneous in terms of their opportunity costs for shopping. The service-providing retailer has a postservice advantage, because customers who have resolved their matching uncertainty through sales service incur zero marginal shopping cost if they purchase from the service-providing retailer rather than the free-riding retailer. Moreover, allowing free riding gives the free rider less incentive to compete with the service provider on price, because many customers eventually will switch to it due to their own free riding. In turn, this induced soft strategic response enables the service provider to charge a higher price and enjoy the strictly positive profit that otherwise would have been wiped away by head-to-head price competition. Therefore, allowing free riding can be regarded as a necessary mechanism that prevents an aggressive response from another retailer and reduces the intensity of price competition.
Airports and Economic Development

This article tests whether the activity at a metropolitan area's airport helps predict population and employment growth. In regression equations explaining employment and population growth, the article uses various measures of airport activity, including boardings, originations, hub status and cargo volume. Because airports may be a function of, as well as a cause of, growth, the article instruments for airports by using geographical and lagged variables. It finds that, under a variety of specifications, passenger activity is a powerful predictor of growth; cargo activity is not.
A laboratory driving simulation for assessment of driving behavior in adults with ADHD: a controlled study

Background It is now estimated that attention deficit-hyperactivity disorder (ADHD) afflicts at least 4% of adults in the United States and is associated with high levels of morbidity and functional impairment. One key area of dysfunction associated with ADHD is impaired motor vehicle operation. Our goal was to examine the association between ADHD and specific driving outcomes in a sample of adults using a driving simulator.
The Mirrlees Approach to Mechanism Design with Renegotiation (with Applications to Hold‐up and Risk Sharing)

The paper studies the implementation problem, first analyzed by Maskin and Moore (1999), in which two agents observe an unverifiable state of nature and may renegotiate inefficient outcomes following play of the mechanism. We develop a first-order approach to characterizing the set of implementable utility mappings in this problem, paralleling Mirrlees's (1971) first-order analysis of standard mechanism design problems. We use this characterization to study optimal contracting in hold-up and risk-sharing models. In particular, we examine when the contracting parties can optimally restrict attention to simple contracts, such as noncontingent contracts and option contracts (where only one agent sends a message).
Ribosome profiling reveals post-transcriptional buffering of divergent gene expression in yeast

Understanding the patterns and causes of phenotypic divergence is a central goal in evolutionary biology. Much work has shown that mRNA abundance is highly variable between closely related species. However, the extent and mechanisms of post-transcriptional gene regulatory evolution are largely unknown. Here we used ribosome profiling to compare transcript abundance and translation efficiency in two closely related yeast species (S. cerevisiae and S. paradoxus). By comparing translation regulatory divergence to interspecies differences in mRNA sequence features, we show that differences in transcript leaders and codon bias substantially contribute to divergent translation. Globally, we find that translation regulatory divergence often buffers species differences in mRNA abundance, such that ribosome occupancy is more conserved than transcript abundance. We used allele-specific ribosome profiling in interspecies hybrids to compare the relative contributions of cis- and trans-regulatory divergence to species differences in mRNA abundance and translation efficiency. The mode of gene regulatory divergence differs for these processes, as trans-regulatory changes play a greater role in divergent mRNA abundance than in divergent translation efficiency. Strikingly, most genes with aberrant transcript abundance in F1 hybrids (either over- or underexpressed compared to both parent species) did not exhibit aberrant ribosome occupancy. Our results show that interspecies differences in translation contribute substantially to the evolution of gene expression. Compensatory differences in transcript abundance and translation efficiency may increase the robustness of gene regulation.
Collecting unused processing capacity: an analysis of transient distributed systems

It is suggested that if the large numbers of idle computers and workstations in distributed systems could be used then considerable computing power could be harnessed at low cost. Such systems are analyzed using Brownian motion with drift to model the execution of a program distributed over the idle computers in a network of idle and busy processors. The ways in which the use of these transient processors affects a program's execution time is determined. The probability density of a program's finishing time on both single and multiple transient processors is found. These results are explored for qualitative insight. Some approximations for the finishing time probability density are suggested. >
Two-channel tests for common non-Gaussian signal detection

The problem of detecting an unknown, random, stationary, non-Gaussian signal that is common to two spatially separated sensors, is considered. The signal is assumed to have nonvanishing bispectrum. The measurement noise sequences at the two sensors are either mutually independent with arbitrary cumulant spectra, or dependent with vanishing bispectra. Two statistical tests are presented for signal detection when the noise statistics are unknown. The performance of the tests is illustrated via simulation examples. >
Optimal Financial Crises

Empirical evidence suggests that banking panics are related to the business cycle and are not simply the result of "sunspots." Panics occur when depositors perceive that the returns on bank assets are going to be unusually low. We develop a simple model of this. In this setting, bank runs can be first-best efficient: they allow efficient risk sharing between early and late withdrawing depositors and they allow banks to hold efficient portfolios. However, if costly runs or markets for risky assets are introduced, central bank intervention of the right kind can lead to a Pareto improvement in welfare. FROM THE EARLIEST TIMES, banks have been plagued by the problem of bank runs in which many or all of the bank's depositors attempt to withdraw their funds simultaneously. Because banks issue liquid liabilities in the form of deposit contracts, but invest in illiquid assets in the form of loans, they are vulnerable to runs that can lead to closure and liquidation. A financial crisis or banking panic occurs when depositors at many or all of the banks in a region or a country attempt to withdraw their funds simultaneously. Prior to the twentieth century, banking panics occurred frequently in Europe and the United States. Panics were generally regarded as a bad thing and the development of central banks to eliminate panics and ensure financial stability has been an important feature of the history of financial systems. It has been a long and involved process. The first cerntral bank, the Bank of Sweden, was established more than 300 years ago. The Bank of England played an especially important role in the development of effective stabilization policies in the eighteenth and nineteenth centuries. By the end of the nineteenth century, banking panics had been eliminated in Europe. The last true panic in England was the Overend, Gurney & Company Crisis of 1866.
Regional decentralization and fiscal incentives: Federalism, Chinese style

Abstract Aligning the interests of local governments with market development is an important issue for developing and transition economies. Using a panel data set from China, we investigate the relationship between provincial government's fiscal incentives and provincial market development. We report three empirical findings. First, we find that during the period of “fiscal contracting system” the discrepancy between ex ante contracts and ex post implementation was relatively small, suggesting that the fiscal contracts were credible. Second, we find a much higher correlation, about four times, between the provincial government's budgetary revenue and its expenditure during 1980s and 1990s as compared to 1970s, demonstrating that provincial governments faced much stronger ex post fiscal incentives after reform. Third, we find that stronger ex ante fiscal incentives, measured by the contractual marginal retention rate of the provincial government in its budgetary revenue, are associated with faster development of the non-state sector as well as more reforms in the state sector in the provincial economy. This holds even when we control for the conventional measure of fiscal decentralization. Finally, we compare federalism, Chinese style, to federalism, Russian style.
Why do manufacturers issue coupons? An empirical analysis of breakfast cereals

We explore the relationship between shelf prices and manufacturers’ coupons for 25 readyto-eat breakfast cereals. We find that shelf prices are lower during periods when coupons are available. This result is inconsistent with static monopoly price discrimination under a broad range of assumptions. We present evidence that is inconsistent with both dynamic theories of price discrimination and explanations of couponing based on the vertical relationship between manufacturers and retailers. We find support for models of price discrimination in oligopoly settings as well as suggestions that firmwide incentives may induce managers to use coupons and price cuts simultaneously. Finally, lagged coupons have a positive effect on current sales, suggesting that coupons are used to induce repurchase.
The evolution of information technology management at the federal level: implications for public administration

Federal agencies rely extensively on information technology (IT) to perform basic missions. Arguably, public administration should be driving the theory, policy, and practice for managing these increasingly important resources. This is especially true as public organizations move to electronic government.Despite some maturation in the literature for managing IT in federal agencies in the last several years, public administration has contributed little to this effort. Other academic fields, such as information science, business administration, and practitioners from the federal government and related contractors have contributed more recently to the theory and practice of IT management at the federal level than public administration.This chapter analyzes federal IT management literature from several academic disciplines and government documents. The analysis compares federal IT management with a normative model of management maturity focusing on the strategic objectives for IT and related management approaches. Public administration's minimal contribution to federal IT management raises profound questions whether federal agencies are performing commensurate with public expectations in an information age.