cssi/SciSciGPT-SciSciNet huggingface dataset:
Contribution of the North Atlantic subtropical high to regional climate model (RCM) skill in simulating southeastern United States summer precipitation

This study assesses the skill of advanced regional climate models (RCMs) in simulating southeastern United States (SE US) summer precipitation and explores the physical mechanisms responsible for the simulation skill at a process level. Analysis of the RCM output for the North American Regional Climate Change Assessment Program indicates that the RCM simulations of summer precipitation show the largest biases and a remarkable spread over the SE US compared to other regions in the contiguous US. The causes of such a spread are investigated by performing simulations using the Weather Research and Forecasting (WRF) model, a next-generation RCM developed by the US National Center for Atmospheric Research. The results show that the simulated biases in SE US summer precipitation are due mainly to the misrepresentation of the modeled North Atlantic subtropical high (NASH) western ridge. In the WRF simulations, the NASH western ridge shifts 7° northwestward when compared to that in the reanalysis ensemble, leading to a dry bias in the simulated summer precipitation according to the relationship between the NASH western ridge and summer precipitation over the southeast. Experiments utilizing the four dimensional data assimilation technique further suggest that the improved representation of the circulation patterns (i.e., wind fields) associated with the NASH western ridge substantially reduces the bias in the simulated SE US summer precipitation. Our analysis of circulation dynamics indicates that the NASH western ridge in the WRF simulations is significantly influenced by the simulated planetary boundary layer (PBL) processes over the Gulf of Mexico. Specifically, a decrease (increase) in the simulated PBL height tends to stabilize (destabilize) the lower troposphere over the Gulf of Mexico, and thus inhibits (favors) the onset and/or development of convection. Such changes in tropical convection induce a tropical–extratropical teleconnection pattern, which modulates the circulation along the NASH western ridge in the WRF simulations and contributes to the modeled precipitation biases over the SE US. In conclusion, our study demonstrates that the NASH western ridge is an important factor responsible for the RCM skill in simulating SE US summer precipitation. Furthermore, the improvements in the PBL parameterizations for the Gulf of Mexico might help advance RCM skill in representing the NASH western ridge circulation and summer precipitation over the SE US.
ON SYMMETRIC DEGENERACY LOCI, SPACES OF SYMMETRIC MATRICES OF CONSTANT RANK AND DUAL VARIETIES

Let X be a nonsingular simply connected projective variety of dimension m, E a rank n vector bundle on X, and L a line bundle on X. Suppose that $S^2(E^{*}) \otimes L$ is an ample vector bundle and that there is a constant even rank $r \ge 2$ symmetric bundle map $E \to E^{*} \otimes L$. We prove that $m \le n-r$. We use this result to solve the constant rank problem for symmetric matrices, proving that the maximal dimension of a linear subspace of the space of $m\times m$ symmetric matrices such that each nonzero element has even rank $r \ge 2$ is $m-r+1$. We explain how this result relates to the study of dual varieties in projective geometry and give some applications and examples.
Mediation and Spillover Effects in Group-Randomized Trials: A Case Study of the 4Rs Educational Intervention

Peer influence and social interactions can give rise to spillover effects in which the exposure of one individual may affect outcomes of other individuals. Even if the intervention under study occurs at the group or cluster level as in group-randomized trials, spillover effects can occur when the mediator of interest is measured at a lower level than the treatment. Evaluators who choose groups rather than individuals as experimental units in a randomized trial often anticipate that the desirable changes in targeted social behaviors will be reinforced through interference among individuals in a group exposed to the same treatment. In an empirical evaluation of the effect of a school-wide intervention on reducing individual students’ depressive symptoms, schools in matched pairs were randomly assigned to the 4Rs intervention or the control condition. Class quality was hypothesized as an important mediator assessed at the classroom level. We reason that the quality of one classroom may affect outcomes of chi...
Oculomotor Inhibition of Return in Normal and Mindless Reading

Oculomotor inhibition of return (O-IOR) is an increase in saccade latency prior to an eye movement to a recently fixated location, as compared with other locations. To investigate O-IOR in reading, subjects participated in two conditions while their eye movements were recorded: normal reading and mindless reading with words replaced by geometric shapes. We investigated the manifestation of O-IOR in reading and whether it is related to extracting meaning from the text or is an oculomotor phenomenon. The results indicated that fixation durations prior to a saccade returning to the immediately preceding fixated word were longer than those to other words, consistent with O-IOR. Furthermore, fixation durations were longest prior to a saccade that returned the eyes to the specific character position in the word that had previously been fixated and dropped off as the distance between the previously fixated character and landing position increased. This result is consistent with the hypothesis that O-IOR is relatively precise in its application during reading and drops off as a gradient. Both of these results were found for text reading and for mindless reading, suggesting that they are consequences of oculomotor control, and not of language processing. Finally, although these temporal IOR effects were robust, no spatial consequences of IOR were observed: Previously fixated words and characters were as likely to be refixated as new words and characters.
Hausdorff dimension and Kleinian groups

Let G be a non-elementary, finitely generated Kleinian group, Lambda(G) its limit set and Omega(G) = S \ Lambda(G) (S = the sphere) its set of discontinuity. Let delta(G) be the critical exponent for the Poincar\'e series and let Lambda_c be the conical limit set of G. Suppose Omega_0 is a simply connected component of Omega(G). We prove that (1) delta(G) = dim(Lambda_c). (2) A simply connected component Omega is either a disk or dim(Omega)>1$. (3) Lambda(G) is either totally disconnected, a circle or has dimension > 1, (4) G is geometrically infinite iff dim(Lambda)=2. (5) If G_n \to G algebraically then dim(Lambda) <= \liminf dim(Lambda_n). (6) The Minkowski dimension of Lambda equals the Hausdorff dimension. (7) If Area(Lambda)=0 then delta(G) = dim(Lambda(G)). The proof also shows that \dim(Lambda(G)) > 1 iff the conical limit set has dimension > 1 iff the Poincar\'e exponent of the group is > 1. Furthermore, a simply connected component of Omega(G) either is a disk or has non-differentiable boundary in the the sense that the (inner) tangent points of \partial Omega have zero 1-dimensional measure. Almost every point (with respect to harmonic measure) is a twist point.
Distributed Queuing in Dynamic Networks

We consider the problem of forming a distributed queue in the synchronous dynamic network model of Kuhn, Lynch, and Oshman (STOC 2010) in which the network topology changes from round to round but the network stays connected. Queue requests may arrive over rounds at network nodes and the goal is to eventually enqueue them in a distributed queue. We show that in 1-interval connected graphs, where the communication links change arbitrarily between every round, it is possible to solve the distributed queueing problem in O(nk) rounds using O (logn) size messages, where n is the number of nodes in the network and k≤n is the number of queue requests. Further, we show that for more stable graphs, e.g. T-interval connected graphs where the communication links change in every T≥2 rounds, the distributed queuing problem can be solved in O(n+nkmin{α,T}) rounds using the same O (logn) size messages, where α>0 is the concurrency level parameter that captures the minimum number of active queue requests in the system at any round. These results hold in any arbitrary arrival of queue requests and ensure correctness of the queue formed. To our best knowledge, these are the first solutions to the distributed queuing problem in highly dynamic networks.
Development of algorithms for predicting ignition probabilities and explosion frequencies

Abstract A project was performed for the Explosion Research Cooperative to develop algorithms for predicting the frequencies of explosions based on a variety of design, operating and environmental conditions. Algorithms were developed for estimating unit-based explosion frequencies, such as those reported in API Recommended Practice 752, but in more detail and covering a much broader range of chemical process types. The project also developed methods for predicting scenario-based explosion frequencies, using frequencies of initiating events and conditional probabilities of immediate ignition and delayed ignition resulting in explosion. The algorithms were based on a combination of published data and expert opinion.
Induction of spermatogenesis and achievement of pregnancy after microsurgical varicocelectomy in men with azoospermia and severe oligoasthenospermia.

Abstract Objective: To characterize treatment outcome after varicocele repair in men with azoospermia and severe oligoasthenospermia. Design: Prospective nonrandomized study. Setting: University-based medical center. Patient(s): Seventy-eight men with a palpable varicocele and absolute azoospermia (n = 22) or severe oligoasthenospermia (n = 56). Intervention(s): Microsurgical varicocelectomy. Main Outcome Measure(s): Sperm count and pregnancy rate. Result(s): Twelve (55%) of the 22 men with azoospermia and 35 (69%) of the 51 men with zero motile sperm before surgery had motile sperm observed in their ejaculate after varicocele repair. The total number of motile sperm per ejaculate increased from 0.08 ± 0.02 × 10 6 before varicocelectomy to 7.2 ± 2.3 × 10 6 afterward. Twenty-four men (31%)contributed to pregnancies leading to live births (15 unassisted [19%]), including 3 men with azoospermia preoperatively. Conclusion(s): Varicocele repair resulted in the induction or enhancement of spermatogenesis for most men with azoospermia or severe oligoasthenospermia. Unassisted pregnancies after varicocele repair in men with profound abnormalities of spermatogenesis are possible. Varicocele repair should be considered for all men with azoospermia and severe oligoasthenospermia.
Galaxy Merger Statistics and Inferred Bulge-to-Disk Ratios in Cosmological SPH Simulations

We construct merger trees for galaxies identified in a cosmological hydrodynamic simulation and use them to characterize predicted merger rates as a function of redshift, galaxy mass, and merger mass ratio. At z = 0.3, we find a mean rate of 0.054 mergers per galaxy per Gyr above a 1 : 2 mass ratio threshold for massive galaxies (baryonic mass above 6.4 × 1010 M☉), but only 0.018 Gyr-1 for lower mass galaxies. The mass ratio distribution is ∝R for the massive galaxy sample, so high-mass mergers dominate the total merger growth rate. The predicted rates increase rapidly with increasing redshift, and they agree reasonably well with observational estimates. A substantial fraction of galaxies do not experience any resolved mergers during the course of the simulation, and even for the high-mass sample, only 50% of galaxies experience a greater than 1 : 4 merger since z = 1. Typical galaxies thus have fairly quiescent merger histories. We assign bulge-to-disk ratios to simulated galaxies by assuming that mergers above a mass ratio threshold Rmajor convert stellar disks into spheroids. With Rmajor values of 1 : 4, we obtain a fairly good match to the observed dependence of the early-type fraction on galaxy mass. However, the predicted fraction of truly bulge-dominated systems (fbulge > 0.8) is small, and producing a substantial population of bulge-dominated galaxies may require a mechanism that shuts off gas accretion at late times and/or additional processes (besides major mergers) for producing bulges.
Transverse Electromagnetic Modes in Aperture Waveguides Containing a Metamaterial with Extreme Anisotropy

We show that all modes supported by simply connected apertures containing a metamaterial with extreme anisotropy are purely transverse electromagnetic, dispersion-free, and without cutoff frequency.
Kinetics of Charge‐Transfer Reactions at Nanoscopic Electrochemical Interfaces

After several decades of intensive studies, the questions about the magnitudes of rate constants of rapid heterogeneous electron transfer (ET) and ion transfer (IT) reactions remain open. The fabrication of nanometer-sized metal electrodes and nanopipets enabled electrochemical studies of rapid charge transfer processes at solid/liquid and liquid/liquid nanointerfaces. The nanoelectrochemical techniques offer numerous advantages such as fast mass-transfer rate and simplified analysis of data obtained under steady-state conditions. At the same time, kinetic data obtained at nanointerfaces may be affected by double layer effects, deviations from classical electrochemical theory, and other size-related phenomena. Nanoelectrochemical measurements are also plagued by difficulties in characterizing nanometer-sized interfaces and conductor/insulator boundaries. In this review, we discuss the results of fast electron and ion transfer kinetics measurements at nanointerfaces, along with related reliability problems and some approaches to fixing them.
ICRF wave propagation and absorption in tokamak and mirror magnetic fields: a full-wave calculation

Abstract Global solutions for the ion cyclotron resonant frequency (ICRF) wave fields in a straight tokamak with rotational transform and a poloidally symmetric mirror are calculated in the cold plasma limit. The component of the wave electric field parallel to B is assumed zero. Symmetry in each problem allows Fourier decomposition in one ignorable coordinate, and the remaining set of two coupled, two-dimensional partial differential equations is solved by finite differencing. Energy absorption and antenna impedance are calculated using a simple collisional absorption model. When large gradients in ‖B‖ along B are present in either geometry, ICRF heating at the fundamental ion cyclotron resonance is observed. For the mirror, such gradients are always present. But for the tokamak, the rotational transform must be large enough that B ·▿B ⪆ 0(1) . For smaller transforms more typical of real tokamaks, only heating at the two-ion hybrid resonance is observed. This suggests that direct resonant absorption at the fundamental ion cyclotron resonance may be possible in stellarators where B ·▿ B ≈ 0(1) naturally.
Synthesis and Anticonvulsant Screening of 3,3 -Diphenyl- 2 -pyrrolidone Derivatives

Six derivatives of 3,3-diphenyl-2-pyrrolidone were synthesized and screened for anticonvulsant activity. The synthetic route involved a mono-N-demethylation of an intermediate N,N-dimethylaminonitrile with methyl chloroformate followed by cleavage of the carbamate group. Of the six derivatives, (+/-)-2-imino-1,5-dimethyl-3,3-diphenylpyrrolidine hydrochloride was effective in protecting mice against maximal electroshock (MES) -induced seizures at a 30-mg/kg dose level.
Legal and Ethical Implications of Employee Location Monitoring

This article summarizes the legal and ethical implications associated with employee location monitoring. It states that few international laws and no American laws directly address this location monitoring. International privacy laws and directives, the Electronic Communications Privacy Act, the USA Patriot Act and other laws and directives involving Internet and e-mail monitoring provide the pattern for future location monitoring laws. It also states that ethical considerations such as productivity, security, goodwill, privacy, accuracy, and discipline fairness affect future laws. Furthermore, the authors hope that the understanding of existing laws and ethical considerations associated with electronic monitoring can lead to practical and reasonable location monitoring policies. Employer and employee interests must be balanced. Location monitoring policies should include a legitimate business purpose, ensure that employees are notified that they are being monitored, provide for adequate storage and dissemination of monitoring data, and provide for consistent evaluation of monitoring effectiveness.
Determination of the mean-field momentum-dependence using elliptic flow

Abstract Midrapidity nucleon elliptic flow is studied within the Boltzmann-equation simulations of symmetric heavy-ion collisions. The simulations follow a lattice Hamiltonian extended to relativistic transport. It is demonstrated that in the peripheral heavy-ion collisions the high-momentum elliptic flow is strongly sensitive to the momentum dependence of mean field at supranormal densities. The high transverse-momentum particles are directly and exclusively emitted from the high-density zone in the collisions, while remaining particles primarily continue along the beam axis. The elliptic flow was measured by the KaOS Collaboration as a function of the transverse momentum at a number of impact parameters in Bi + Bi collisions at 400, 700, and 1000 MeV/nucleon. The observed elliptic anisotropies in peripheral collisions, which quickly rise with momentum, can only be explained in simulations when assuming a strong momentum dependence of nucleonic mean field. This momentum dependence must strengthen with the rise of density above normal. The mean-field parametrizations, which describe the data in simulations with various success, are confronted with mean fields from microscopic nuclear-matter calculations. Two of the microscopic potentials in the comparisons have unacceptably weak momentum-dependencies at supranormal densities. The optical potentials from the Dirac–Brueckner–Hartree–Fock calculations, on the other hand, together with the UV14 + TNI potential from variational calculations, agree rather well within the region of sensitivity with the parametrized potentials that best describe the data.
Optical Observations of Black-Hole X-ray Novae

The primary aim of this thesis was to increase the number of dynamically confirmed black hole X-ray novae (BHXNs). As a result of this research, the optical counterpart of an GRO J1655-40 (XN Sco94) has been discovered (Bailyn et al. 1995), and the mass functions of GRO J0422+32, H 1705-250 (XN Oph77), and GRO J1655-40 have been measured (Orosz & Bailyn 1995; Remillard et al. 1996; Bailyn et al. 1995). In addition, the measurements of fundamental system properties of several BXHNs have been refined. Finally, some of the overall properties of the BHXNs as a class are discussed.
The Political Economy of Military Spending in Israel.

Irior scholarly analysis of Israeli military spending has focused on national security questions. We present a mathematical model incorporating security threats as well as electoral cycles and corporate profits. The parameters are estimated empirically. The results support the idea that in Israel the military budget at the margins is also employed as a political-economic instrument to help manage the economy and to provide a favorable election climate for incumbents. It is suggested that the political- economic dynamic widely attributed to Western industrialized societies may be of increasing importance in other societies throughout the world.
Organized crime and the 1960 presidential election

It has been asserted that, based on a pre-election agreement promising them favorable federal treatment, the Chicago Mob (known as the “Outfit”) was responsible for John Kennedy’s election in 1960. An examination of these claims indicates that the sources generally lack credibility and their accounts are implausible. Additionally, there is no evidence Outfit controlled wards/suburbs around Chicago or members of Outfit influenced labor unions voted unusually heavily Democratic in the 1960 presidential election. Therefore, if anything the Outfit “double crossed” the Kennedys by not delivering the promised votes, as opposed to vice-versa.
Wafer-level pulsed-DC electromigration response at very high frequencies

DC and pulsed-DC electromigration tests were performed at the wafer level using standard and self-stressing test structures. DC characterization tests over a very large temperature range (180 to 560/spl deg/C) were consistent with an interface diffusion mechanism in parallel with lattice diffusion. That data allowed for extraction of the respective activation energies and the diffusion coefficient of the rapid mechanism. The ability to extract simultaneously a defect-based diffusion coefficient and activation energy is significant given the extreme difficulty in making those measurements in aluminum. The pulsed-DC experiments were conducted over a range that includes the highest frequency to date, from DC to 500 MHz. Measurements were also made as a function of duty factor from 15% to 100% at selected frequencies. The data shows that the pulsed-DC lifetime is consistent with the average current density model at high (> 10 MHz) frequencies and showed no additional effects at the highest frequency tested (500 MHz). At low frequencies, we attribute the lessened enhancement to thermal effects rather than vacancy relaxation effects. Finally, the deviation in lifetime from the expected current density dependence, characterized over 1 1/2 orders of magnitude in current density, is explained in terms of a shift in the boundary condition for electromigration as the current density is decreased. >
Convex relaxations and linear approximation for optimal power flow in multiphase radial networks

Distribution networks are usually multiphase and radial. To facilitate power flow computation and optimization, two semidefinite programming (SDP) relaxations of the optimal power flow problem and a linear approximation of the power flow are proposed. We prove that the first SDP relaxation is exact if and only if the second one is exact. Case studies show that the second SDP relaxation is numerically exact and that the linear approximation obtains voltages within 0.0016 per unit of their true values for the IEEE 13, 34, 37, 123-bus networks and a real-world 2065-bus network.
Applying the analytic theory of colliding ring galaxies

An analytic theory of the waves in colliding ring galaxies was presented some years ago, but the observations were not of sufficient quality then to make quantitative comparisons. Well-resolved observations of a few systems are now available to make such comparisons, and structure imaged in several dozen systems, derived from the recent compilation of Madore, Nelson and Petrillo and the Galaxy Zoo project, can further constrain the theory. Systems with two rings are especially useful for deriving such constraints. After examining the implications of recent observations of ring sizes and structure, I extend the analytic theory, investigate limiting cases and present several levels of approximation. The theory is especially simple in the case of nearly flat rotation curves. I present observational comparisons for a few systems, including Arp 10, the Cartwheel and AM 2136-492. The fit is quite good over a large range of cases. For the Cartwheel there are discrepancies, but the areas of disagreement are suggestive of additional factors, such as multiple collisions. A specific prediction of the theory in the case of nearly flat rotation curves is that the ratio of the outward velocities of successive rings approximately equals the ratio of ring sizes. Ring velocities are also shown to scale simply with local circular velocities in this limit.
Optical properties of IR materials

Abstract Optical properties of thin films are based on the properties of the bulk material. However, thin films are not always full density, and bulk properties must then be appropriately scaled. A review of phonon and multiphonon contributions to the complex index of refraction for common thin film materials such as oxides and fluorides is presented. Emphasis is on frequency and temperature dependence in terms of mathematical models.
The Accuracy of Doubly Asymptotic Approximations for an Acoustic Half-Space

The accuracy of doubly asymptotic approximations (DAAs) for acoustic half-space problems is assessed by examining their performance for a canonical problem in bispherical coordinates. Exact specific acoustic impedance curves for axisymmetric modal vibrations of a spherical surface near a planar boundary are generated, and corresponding curves based on the first-order DAA and the curvature-corrected DAA are compared with their exact counterparts. The comparisons show that the curvature-corrected DAA is substantially more accurate than the first-order DAA. Also, the curvature-corrected DAA is found to be satisfactory for broad-band excitations regardless of the sphere’s proximity to a compliant (zero-pressure) surface; for a rigid surface, the approximation is satisfactory only if the sphere is located at least one diameter away from the boundary.
Using brain skill assessments to increase productivity in development administration

This article describes how BMS (brain skill and management styles) assessments have and can be used to increase productivity in development administration. The article starts with a brief outline of the management climate which executives face in developing countries (crisis and rapidly changing environments). The article points out that although developing countries have significantly increased their productivity by using traditional quantitative management tools and techniques, they increasingly find that these approaches need to be supplemented with other techniques more appropriate to the environment they must contend with. BMS programmes have been found to be one tool which, combined with established training programmes can serve to increase productivity in developing nations with existing personnel. The article describes what a BMS programme is (identifying human brain skills and management styles that exist in organizations, and matching these skills/styles to the management problem at hand where they can be best employed to enhance productivity), and illustrates how this technique has been used successfully in one developing country. The BMS programme applications in the article are based on the results of testing over 2000 managers and also the experience from implementing in-depth BMS programmes in several countries in a wide variety of organizational settings (business, government, education, military and health).
Toward Equations of Galactic Structure

We find that all classes of galaxies, ranging from disks to spheroids and from dwarf spheroidals to brightest cluster galaxies, lie on a two-dimensional surface within the space defined by the logarithms of the half-light radius, re, mean I-band surface brightness within re, Ie, and internal velocity V2 ≡ (1/2) v2c + σ2, where vc is the rotational velocity and σ is the velocity dispersion. If these quantities are expressed in terms of kpc, L☉ pc−2, and km s−1, then this surface is described by the equation log re − log V2 + log Ie + log Υe + 0.8 = 0, where we provide a fitting function for e, the mass-to-light ratio within re in units of M☉/L☉, that depends only on V and Ie. The scatter about this surface for our heterogeneous sample of 1925 galaxies is small ( 30 km s−1. For systems with internal velocities comparable to that of the Milky Way (149 km s−1 < V < 163 km s−1), η = 0.14 ± 0.05, and ξ is, on average, ~5 times greater for spheroids than for disks.
On the complexity of dataflow analysis of logic programs

It is widely held that there is a correlation between complexity and precision in dataflow analysis, in the sense that the more precise an analysis algorithm, the more computationally expensive it must be. The details of this relationship, however, appear to not have been explored extensively. This article reports some results on this correlation in the context of logic programs. A formal notion of the “precision” of an analysis algorithm is proposed, and this is used to characterize the worst-case computational complexity of a number of dataflow analyses with different degrees of precision. While this article considers the analysis of logic programs, the technique proposed, namely the use of “exactness sets” to study relationships between complexity and precision of analyses, is not specific to logic programming in any way, and is equally applicable to flow analyses of other language families.
Stereocontrolled Synthesis of the Diene and Triene Macrolactones of Oximidines I and II: Organometallic Coupling versus Standard Macrolactonization

Stereocontrolled construction of the 12-membered diene and triene lactones 1, 2, and 3, characteristic of the antitumor agent oximidines I and II, are reported and were based on an intramolecular Castro−Stephens coupling for the construction of a cyclic enyne or dienyne followed by stereoselective reduction of the cyclic alkyne for introduction of the cis-olefin of the targets. A comparison of the effectiveness of this protocol is made with standard macrolactonization.
David Hume on Banking and Hoarding

David Hume opposes banks and favors hoarding. The only bank he reluctantly approves of is a public, 100% reserve bank. Other banks increase money supply and prices, hindering exports and economic growth. For Hume, a 100% reserve public bank would lead to �the destruction of paper-credit� ([1752] 1985, p. 285), fostering economic growth instead by preventing inflation. Additionally, a 100% reserve bank hoards a large quantity of gold and silver, which is available in case of national emergency.
Scalable mechanisms for rational secret sharing

We consider the classical secret sharing problem in the case where all agents are rational. In recent work, Kol and Naor show that, when there are two players, in the non-simultaneous communication model, i.e., when rushing is possible, there is no Nash equilibrium that ensures both players learn the secret. However, they describe a mechanism for this problem, for any number of players, that is an $$\epsilon $$∈-Nash equilibrium, in that no player can gain more than $$\epsilon $$∈ utility by deviating from it. Unfortunately, the Kol and Naor mechanism, and, to the best of our knowledge, all previous mechanisms for this problem require each agent to send $$O(n)$$O(n) messages in expectation, where $$n$$n is the number of agents. We address this issue by describing mechanisms for rational secret sharing that are designed for large $$n \ge 3$$n?3. Our first result is a non-cryptographic mechanism for $$n$$n-out-of-$$n$$n rational secret sharing that is Nash equilibrium, rather than just $$\epsilon $$∈-Nash equilibrium. Our second result is a cryptographic mechanism for rational $$t$$t-out-of-$$n$$n secret sharing that is everlasting $$\epsilon $$∈-Nash equilibrium. Both our mechanisms are scalable in the sense that they requires each player to send only an expected $$O(\log n)$$O(logn) bits. Furthermore, the latency of these mechanisms is $$O(\log n)$$O(logn) in expectation, compared to $$O(n)$$O(n) expected latency for the Kol and Naor result. Both of our mechanisms are not susceptible to backwards induction.
The Use of Solid‐Phase Supports for Derivatization in Chromatography and Spectroscopy

Abstract Derivatization, or chemical modification of analytes, is often required for species that are only weakly detectable by common spectroscopic methods. Derivatization is most commonly performed in homogeneous solution or using phase‐transfer catalyzed reactions. However, the use of solid phase supports for performing the same reactions has a number of advantages. The sample can be “cleaned up” on the same phase, eliminating interfering matrix components or excess reagent. The process naturally concentrates the analyte, providing higher sensitivity, but also, under favorable circumstances, provides for more efficient reactions relative to solutions of the same original concentration. This review explores the uses to which such supports have been put, primarily in fluorescence derivatization for chromatographic applications. Some of the considerations in applying these techniques are described, and they are shown to be an extremely useful format for derivatization.
Tachyon condensation in unstable type I D-brane systems

Type-I string theory provides eight classes of unstable D-brane systems. We determine the gauge group and tachyon spectrum for each one, and thereby describe the gauge symmetry breaking pattern in the low-energy world-volume field theory. The topologies of the resulting coset vacuum manifolds are related to the real K-theory groups KO-n, extending the known relations between the type-II classifying spaces BU and U and the complex K-theory groups K0 and K-1. We also comment on the role of the background D9-branes.
INTRINSIC MOTIVATION, EXTRINSIC REINFORCEMENT, AND INEQUITY

If a person who is intrinsically motivated to perform an activity begins to receive external reinforcement for the activity, what will happen to his intrinsic motivation? Previous studies and the present study indicate that money decreases intrinsic motivation, while verbal reinforcements tend to enhance intrinsic motivation. The beginning of a cognitive evaluation theory is discussed, and an apparently discrepant prediction between this theory and inequity theory is pointed out. It is argued, however, that the theories are not conceptually discrepant, and the present study gives support for this argument. It is possible to distinguish between two broad classes of motivation to perform an activity: intrinsic motivation and extrinsic motivation. A person is intrinsically motivated if he performs an activity for no apparent reward except the activity itself (cf. Berlyne, 1966; Hunt, 1965; White, 1959). Extrinsic motivation, on the other hand, refers to the performance of an activity because it leads to external rewards (e.g., status, approval, or passing grades). The question of interest in this study is whether there will be changes in a person's intrinsic motivation for an activity when he receives external rewards for performing that activity. Deci (1971) reported that external reinforcements do affect intrinsic motivation, and he suggested the initial elements of a cognitive evaluation theory to account for the changes in intrinsic motivation following an experience with extrinsic rewards. The theory focuses on a person's cognitive evaluation of an activity and the reasons for his engaging in the activity. It suggests that distinctions should be made among different kinds of external rewards, since a person's evaluation of different rewards may be different. In turn, this would 1 The author would like to thank Wayne Cascio for serving as the first experimenter and for helping with the data analysis; Victor Vroom for making helpful comments on an earlier draft of the manuscript; and Larry Coff for being the second experimenter.
Mechanisms of cell injury by activated oxygen species.

Current evidence suggests that O2- and H2O2 injure cells as a result of the generation of a more potent oxidizing species. In addition to O2- and H2O2, the third essential component of the complex that mediates the lethal cell injury is a cellular source of ferric iron. The hypothesis most consistent with all the available data suggests that O2- reduces a cellular source of ferric to ferrous iron, and the latter then reacts with H2O2 to produce a more potent oxidizing species, like the .OH or an equivalently reactive species. In turn, .OH initiates the peroxidative decomposition of the phospholipids of cellular membranes. .OH also damages the inner mitochondrial membrane. Upon mitochondrial deenergization, a sequence of events is initiated that similarly leads to the loss of viability of the cell. DNA represents a third cellular target of .OH. Depending on the cell type, oxidative DNA damage can be coupled to cell killing through a mechanism related to the activation of poly (ADP-ribose) polymerase.
When response variability increases neural network robustness to synaptic noise

Cortical sensory neurons are known to be highly variable, in the sense that responses evoked by identical stimuli often change dramatically from trial to trial. The origin of this variability is uncertain, but it is usually interpreted as detrimental noise that reduces the computational accuracy of neural circuits. Here we investigate the possibility that such response variability might in fact be beneficial, because it may partially compensate for a decrease in accuracy due to stochastic changes in the synaptic strengths of a network. We study the interplay between two kinds of noise, response (or neuronal) noise and synaptic noise, by analyzing their joint influence on the accuracy of neural networks trained to perform various tasks. We find an interesting, generic interaction: when fluctuations in the synaptic connections are proportional to their strengths (multiplicative noise), a certain amount of response noise in the input neurons can significantly improve network performance, compared to the same network without response noise. Performance is enhanced because response noise and multiplicative synaptic noise are in some ways equivalent. So if the algorithm used to find the optimal synaptic weights can take into account the variability of the model neurons, it can also take into account the variability of the synapses. Thus, the connection patterns generated with response noise are typically more resistant to synaptic degradation than those obtained without response noise. As a consequence of this interplay, if multiplicative synaptic noise is present, it is better to have response noise in the network than not to have it. These results are demonstrated analytically for the most basic network consisting of two input neurons and one output neuron performing a simple classification task, but computer simulations show that the phenomenon persists in a wide range of architectures, including recurrent (attractor) networks and sensorimotor networks that perform coordinate transformations. The results suggest that response variability could play an important dynamic role in networks that continuously learn.
Cosmological Constraints on Tachyon Matter

Abstract We examine whether tachyon matter is a viable candidate for the cosmological dark matter. First, we demonstrate that in order for the density of tachyon matter to have an acceptable value today, the magnitude of the tachyon potential energy at the onset of rolling must be finely tuned. For a tachyon potential V(T)∼MPl4exp(−T/τ), the tachyon must start rolling at T≃60τ in order for the density of tachyon matter today to satisfy Ω T,0 ∼1 , provided that standard big bang cosmology begins at the same time as the tachyon begins to roll. In this case, the value of Ω T,0 is exponentially sensitive to T/τ at the onset of rolling, so smaller T/τ is unacceptable, and larger T/τ implies a tachyon density that is too small to have interesting cosmological effects. If instead the universe undergoes a second inflationary epoch after the tachyon has already rolled considerably, then the tachyon can begin with T near zero, but the increase of the scale factor during inflation must still be finely tuned in order for Ω T,0 ∼1 . Second, we show that tachyon matter, unlike quintessence, can cluster gravitationally on very small scales. If the starting value of T/τ is tuned finely enough that Ω T,0 ∼1 , then tachyon matter clusters more or less identically to pressureless dust. Thus, if the fine-tuning problem can be explained, tachyon matter is a viable candidate for cosmological dark matter.
UNDERWRITER REPUTATION AND AFTERMARKET PERFORMANCE OF CLOSED‐END FUNDS

I find a positive relation between underwriter reputation and the initial and long-run aftermarket performance of closed-end funds. This relation persists even after controlling for fund characteristics, types, and investment strategies. The positive relation between underwriter reputation and initial returns supports the notion that prestigious investment bankers tend to promote a price run-up in the immediate aftermarket to enhance their reputation with the issuers and the investors. The better long-run performance for funds underwritten by prestigious underwriters suggests that prestigious underwriters protect their reputation by underwriting only high-quality issues that will perform well in the long run.
A Meditation on Mediation: Evidence That Structural Equations Models Perform Better Than Regressions

In this paper, we suggest ways to improve mediation analysis practice among consumer behavior researchers. We review the current methodology and demonstrate the superiority of structural equations modeling, both for assessing the classic mediation questions and for enabling researchers to extend beyond these basic inquiries. A series of simulations are presented to support the claim that the approach is superior. In addition to statistical demonstrations, logical arguments are presented, particularly regarding the introduction of a fourth construct into the mediation system. We close the paper with new prescriptive instructions for mediation analyses.
Mind, matter, and quantum mechanics

The purpose of this work is to resolve together four basic questions concerning the nature of nature. These questions are: (1) How is mind related to matter? (2) How is quantum theory related to reality? (3) How is relativity theory reconciled globally with that which locally we experience directly, namely the coming of reality into being or existence? (4) How is relativity theory reconciled with the apparent demand of Bell’s theorem that what happens in one spacetime region must, in certain situations, depend on decisions made in a spacelike-separated region? These four questions will be discussed in detail later. They are probably the four most fundamental questions in science.
What Would Adam Smith Have on His iPod? Uses of Music in Teaching the History of Economic Thought

In this article, the authors examine two ways that they use music (i.e., popular song lyrics) as an active learning technique in an undergraduate history of economic thought course. First, they use music to help students grasp the ideas of the great thinkers in economics and see their relevance today. Second, because they require students to read original texts and write thesis-driven essays, they use music to teach essential skills related to such assignments. While the article focuses on how they use music as a pedagogical device to teach the history of economic thought, the use of music to teach essential skills could be applied to any economics course in which students engage in higher-level reading and writing.
Enzymatic ketone reduction: mapping the substrate profile of a short-chain alcohol dehydrogenase (YMR226c) from Saccharomyces cerevisiae

Abstract A short-chain alcohol dehydrogenase (YMR226c) from Saccharomyces cerevisiae was cloned and expressed in Escherichia coli, and the encoded protein was purified. The activity and enantioselectivity of this recombinant enzyme were evaluated with a series of ketones. The alcohol dehydrogenase (YMR226c) was found to effectively catalyze the enantioselective reductions of aryl-substituted acetophenones, α-chloroacetophenones, aliphatic ketones, and α- and β-ketoesters. While the enantioselectivity for the reduction of β-ketoesters was moderate, the acetophenone derivatives, aromatic α-ketoesters, some substituted α-chloroacetophenones, and aliphatic ketones were reduced to the corresponding chiral alcohols with excellent enantioselectivity. The enantiopreference of this enzyme generally followed Prelog’s rule for the simple ketones. The ester functionality played some role in determining the enzyme’s enantiopreference for the reduction of α- and β-ketoesters. The present study serves as a valuable guidance for the future applications of this versatile biocatalyst.
Edge dynamics for BF theories and gravity

Abstract We discuss BF theories defined on manifolds with spatial boundaries. Variational arguments show that one needs to augment the usual action with a boundary term for specific types of boundary conditions. We also show how to use this procedure to find the boundary actions for theories of gravity with first order formulations. Possible connection with the membrane approach is also pointed out.
A finite algorithm for the linear exchange model

It is shown that Lemke's algorithm can be used to compute, in a finite number of steps, an equilibrium or reduction for the pure exchange model with linear utilities.
A novel preparation of thiazolo[5,4-c]pyridines and the synthesis of some imidazo[4,5-c]pyridines and oxazolo[4,5-c]pyridines

Diethoxymethyl acetate was used to cyclize o-disubstituted aminopyridines to oxazolo[4,5-c]pyridines and imidazo[4,5-c]pyridines. All the possible imidazole-methylated imidazo[4,5-c]pyridines were prepared. A novel synthesis of 2-substituted thiazolo[5,4-c]pyridines and 4-amino-3-pyridinethiol was discovered.
Using Two Chemical Exchange Saturation Transfer Magnetic Resonance Imaging Contrast Agents for Molecular Imaging Studies

Responsive magnetic resonance imaging (MRI) contrast agents can change MR image contrast in response to a molecular biomarker. Quantitative detection of the biomarker requires an accounting of the other effects that may alter MR image contrast, such as a change in the agent’s concentration, magnetic field variations, and hardware sensitivity profiles. A second unresponsive MRI contrast agent may serve as an “internal control” to isolate the detection of the molecular biomarker. Chemical exchange saturation transfer (CEST) MRI contrast agents can be selectively detected, providing the opportunity to combine a responsive CEST agent and an unresponsive CEST agent during the same MRI scan session. When two CEST MRI contrast agents are used for molecular imaging applications, the CEST agents should be designed to maximize accurate quantification of the concentrations of the two agents. From a chemical perspective, CEST agents behave like enzymes that catalyze the conversion of an unsaturated water “substrate” ...
Learning a circuit by injecting values

We propose a new model for exact learning of acyclic circuits using experiments in which chosen values may be assigned to an arbitrary subset of wires internal to the circuit, but only the value of the circuit's single output wire may be observed. We give polynomial time algorithms to learn (1) arbitrary circuits with logarithmic depth and constant fan-in and (2) Boolean circuits of constant depth and unbounded fan-in over AND, OR, and NOT gates. Thus, both AC0 and NC1 circuits are learnable in polynomial time in this model. Negative results show that some restrictions on depth, fan-in and gate types are necessary: exponentially many experiments are required to learn AND/OR circuits of unbounded depth and fan-in; it is NP-hard to learn AND/OR circuits of unbounded depth and fan-in 2; and it is NP-hard to learn circuits of constant depth and unbounded fan-in over AND, OR, and threshold gates, even when the target circuit is known to contain at most one threshold gate and that threshold gate has threshold 2. We also consider the effect of adding an oracle for behavioral equivalence. In this case there are polynomial-time algorithms to learn arbitrary circuits of constant fan-in and unbounded depth and to learn Boolean circuits with arbitrary fan-in and unbounded depth over AND, OR, and NOT gates. A corollary is that these two classes are PAC-learnable if experiments are available. Finally, we consider an extension of the model called the synchronous model. We show that an even more general class of circuits are learnable in this model. In particular, we are able to learn circuits with cycles.