cssi/SciSciGPT-SciSciNet huggingface dataset:
On Modeling and Interpreting the Economics of Catastrophic Climate Change

With climate change as prototype example, this paper analyzes the implications of structural uncertainty for the economics of low- probability, high-impact catastrophes. Even when updated by Bayesian learning, uncertain structural parameters induce a critical "tail fattening" of posterior-predictive distributions. Such fattened tails have strong im- plications for situations, like climate change, where a catastrophe is theoretically possible because prior knowledge cannot place sufficiently narrow bounds on overall damages. This paper shows that the economic consequences of fat-tailed structural uncertainty (along with unsureness about high-temperature damages) can readily outweigh the effects of discounting in climate-change policy analysis.
Distribution of surplus in sequential bargaining with endogenous recognition

I examine a sequential bargaining situation in which agents contest the right to propose an allocation. The contest can either take place at a pre-bargaining stage, yielding “persistent recognition” to propose, or recur throughout the bargaining, yielding “transitory recognition”. Equilibrium analysis reveals that surplus is distributed more unequally under persistent recognition; social cost is higher under persistent recognition if and only if it attracts a sufficient number of “active” bargainers; and individual’s incentive to propose under transitory recognition may actually increase in the number of agents, while this incentive always diminishes under persistent recognition.
Statistical methods for estimating complexity from competition experiments between two populations

Often a screening or selection experiment targets a cell or tissue, which presents many possible molecular targets and identifies a correspondingly large number of ligands. We describe a statistical method to extract an estimate of the complexity or richness of the set of molecular targets from competition experiments between distinguishable ligands, including aptamers derived from combinatorial experiments (SELEX or phage display). In simulations, the non-parametric statistic provides a robust estimate of complexity from a 100 x100 matrix of competition experiments, which is clearly feasible in high-throughput format. The statistic and method are potentially applicable to other ligand binding situations.
ON COVARIANT DERIVATIVES AND GAUGE INVARIANCE IN THE PROPER TIME FORMALISM FOR STRING THEORY

It is shown that the idea of “minimal” coupling to gauge fields can be conveniently implemented in the proper time formalism by identifying the equivalent of a “covariant derivative”. This captures some of the geometric notion of the gauge field as a connection. The proper time equation is also generalized so that the gauge invariances associated with higher spin massive modes can be made manifest, at the free level, using loop variables. Some explicit examples are worked out illustrating these ideas.
Design of active ripple filters for power circuits operating in the 1-10 MHz range

A fundamental analysis of active ripple filters for powder circuits operating in 1-10 MHz range is presented. The improved understanding derived from this analysis allows filter circuits with gains five to ten times higher than previously reported to be built. Besides providing further reduction in the size of 1 MHz ripple filters, these higher gains make the active filters valuable for power circuit switching near 10 MHz. >
Quantum dynamics in dual spaces

Quantum mechanics gives us information about the spectra of dynamical variables and transition rates including scattering cross sections. They can be exhibited as spectral information in analytically continued spaces and their duals. Quantum mechanics formulated in these generalized spaces is used to study scattering and time evolution. It is shown that the usual asymptotic condition is inadequate to deal with the scattering of composite or unstable particles. Scattering theory needs an amendment when the interacting system is not isospectral with the free Hamiltonian; the amendment is formulated. Perturbation theory in generalized spaces is developed and used to study the deletion and augmentation of the spectrum of the Hamiltonian. A complete set of algebraically independent constants for an interacting system is obtained. The question of the breaking of time symmetry is discussed.
The Conformal Anomaly of M5-Branes

We show that the conformal anomaly for N M5-branes grows like N 3. The method we employ relates Coulomb branch interactions in six dimensions to interactions in four dimensions using supersymmetry. This leads to a relation between the six-dimensional conformal anomaly and the conformal anomaly of N = 4 Yang-Mills. Along the way, we determine the structure of the four derivative interactions for the toroidally compactified (2, 0) theory, while encountering interesting novelties in the structure of the six derivative interactions.
Dynamic optical coherence elastography and applications

Dynamic optical coherence elastography, an emerging optical technique to measure material mechanical properties using the non-invasive imaging modality of optical coherence tomography is introduced. Dynamic mechanical excitations were applied to the samples while a spectral domain optical coherence tomography system was used for detection. Based on a simple mechanical model, material mechanical properties such as Young's moduli can be extracted from detected phase-resolved signals. Biological tissues and their biomechanical properties are currently the main objects for this technique due to its micron-scale resolution and relatively deep penetration. Quantitative results were achieved by this technique on tissue phantoms and rat tumor tissues. Different excitation approaches and applications for dynamic optical coherence elastography are also discussed.
Rho activation is apically restricted by Arhgap1 in neural crest cells and drives epithelial-to-mesenchymal transition

Epithelial-to-mesenchymal transitions (EMTs) are crucial for morphogenesis and carcinoma metastasis, yet mechanisms controlling the underlying cell behaviors are poorly understood. RhoGTPase signaling has been implicated in EMT; however, previous studies have yielded conflicting results regarding Rho function, and its role in EMT remains poorly understood. Elucidation of precise Rho functions has been challenging because Rho signaling is highly context dependent and its activity is tightly regulated spatiotemporally within the cell. To date, few studies have examined how Rho affects cell motility in intact organisms, and the pattern of Rho activity during motile cell behaviors of EMT has not been determined in any system. Here, we image endogenous active Rho during EMT in vivo, and analyze effects of Rho and Rho-kinase (ROCK) manipulation on cell motility in vivo. We show that Rho is activated in a discrete apical region of premigratory neural crest cells during EMT, and Rho-ROCK signaling is essential for apical detachment and generation of motility within the neuroepithelium, a process that has been poorly understood. Furthermore, we find that Arhgap1 restricts Rho activation to apical areas, and this restriction is necessary for detachment. Our results provide new insight into mechanisms controlling local Rho activation and how it affects dynamic cell behaviors and actomyosin contraction during key steps of EMT in an intact living organism.
UNIVERSAL FEATURES IN THE GROWTH DYNAMICS OF COMPLEX ORGANIZATIONS

We analyze the fluctuations in the gross domestic product (GDP) of 152 countries for the period 1950 ‐ 1992. We find that (i) the distribution of annual growth rates for countries of a given GDP decays with “fatter” tails than for a Gaussian, and (ii) the width of the distribution scales as a power law of GDP with a scaling exponent b 0.15. Both findings are in surprising agreement with results on firm growth. These results are consistent with the hypothesis that the evolution of organizations with complex structure is governed by similar growth mechanisms. [S0031-9007(98)07339-6] PACS numbers: 02.50.Ey, 01.75. + m, 05.40. + j, 05.45. + b In the study of physical systems, the analysis of the scaling properties of the fluctuations has been shown to give important information regarding the underlying processes responsible for the observed macroscopic behavior. In contrast, most studies on the time evolution of economic time series have concentrated on average growth rates [1‐18]. Here, we investigate the possibility that the study of fluctuations in economics may also lead to a better understanding of the mechanisms responsible for the observed dynamics [19‐ 23]. We therefore analyze the fluctuations in the growth rate of the gross domestic product (GDP) of 152 countries during the period 1950 ‐ 1992 [24]. We will show that (i) the distribution of annual growth rates for countries of a given GDP is consistent for a certain range with an exponential decay, and (ii) the width of the distribution scales as a power law of GDP with a scaling exponent b 0.15. Both findings are in surprising agreement with
Anthropogenic transformation of the terrestrial biosphere

Human populations and their use of land have transformed most of the terrestrial biosphere into anthropogenic biomes (anthromes), causing a variety of novel ecological patterns and processes to emerge. To assess whether human populations and their use of land have directly altered the terrestrial biosphere sufficiently to indicate that the Earth system has entered a new geological epoch, spatially explicit global estimates of human populations and their use of land were analysed across the Holocene for their potential to induce irreversible novel transformation of the terrestrial biosphere. Human alteration of the terrestrial biosphere has been significant for more than 8000 years. However, only in the past century has the majority of the terrestrial biosphere been transformed into intensively used anthromes with predominantly novel anthropogenic ecological processes. At present, even were human populations to decline substantially or use of land become far more efficient, the current global extent, duration, type and intensity of human transformation of ecosystems have already irreversibly altered the terrestrial biosphere at levels sufficient to leave an unambiguous geological record differing substantially from that of the Holocene or any prior epoch. It remains to be seen whether the anthropogenic biosphere will be sustained and continue to evolve.
Ultrasound-guided procedures for the office

Over the past decade, ultrasonography (US) has become an instrumental component in the diagnostic evaluation of a multitude of head and neck pathologies. The technology can also be beneficial for image guidance during percutaneous and open head and neck procedures. Although US-guided fine-needle aspiration biopsy (FNAB) accounts for the vast majority of these procedures, US guidance can also be used for aspiration of fluid collections and therapeutic injections as well as an intraoperative adjuvant to guide revision surgery. A thorough understanding of the capabilities of interventional US allows optimal management of a wide variety of complex clinical scenarios.
Bounding heavy meson form factors using inclusive sum rules

Abstract We utilize inclusive sum rules to construct both upper and lower bounds on the form factors for B → D , D ∗ , ϱ, π, ω, K and K ∗ semi-leptonic and radiative decays. We include the leading nonperturbative 1 E corrections and point out cases when α s corrections are equally important. We compute the α s correction to the lower bound on the B → D ∗ form factor f ( w ) at zero recoil, thereby constraining its normalization f (1) to within 6–8% of the upper bound. We show that the B → ϱ form factor α + is suppressed at small momentum transfer by either a factor of 1 E or α s . These bounds can be used to rule out phenomenological models as well as to determine values for the CKM matrix elements once radiative corrections are included.
On enlarging the basin of attraction for linear systems under saturated linear feedback

We consider the problem of enlarging the basin of attraction for a linear system under saturated linear feedback. An LMI-based approach to this problem is developed. For discrete-time system, this approach is enhanced by the lifting technique, which leads to further enlargement of the basin of attraction. The low convergence rate inherent with the large invariant set (hence, the large basin of attraction) is prevented by the construction of a sequence of invariant ellipsoids nested within the large one obtained.
MIMO-MC radar: A MIMO radar approach based on matrix completion

In a typical multiple-input and multiple-output (MIMO) radar scenario, the receive nodes transmit to a fusion center either samples of the target returns, or the results of matched filtering with the transmit waveforms. Based on the data it receives from multiple antennas, the fusion center formulates a matrix, referred to as the data matrix, which, via standard array processing schemes leads to target detection and parameter estimation. In this paper, it is shown that under certain conditions, the data matrix is low rank and thus can be recovered based on knowledge of a small subset of its entries via matrix completion (MC) techniques. Leveraging the low-rank property of the data matrix, we propose a new MIMO radar approach, termed, MIMO-MC radar, in which each receive node either performs matched filtering with a small number of randomly selected dictionary waveforms or obtains sub-Nyquist samples of the target returns at random sampling instants, and forwards the results to a fusion center. Based on the received samples, and with knowledge of the sampling scheme, the fusion center partially fills the data matrix and subsequently applies MC techniques to estimate the full matrix. MIMO-MC radars share the advantages of MIMO radars with compressive sensing, (MIMO-CS), i.e., high resolution with reduced amounts of data, but unlike MIMO-CS radars do not require grid discretization. The MIMO-MC radar concept is illustrated through a uniform linear array configuration, and its target estimation performance is demonstrated via simulations.
On the Connectivity and Multihop Delay of Ad Hoc Cognitive Radio Networks

We analyze the multihop delay of ad hoc cognitive radio networks, where the transmission delay of each hop consists of the propagation delay and the waiting time for the availability of the communication channel (i.e. the occurrence of a spectrum opportunity at this hop). Using theories and techniques from continuum percolation and ergodicity, we establish the scaling law of the minimum multihop delay with respect to the source-destination distance in cognitive radio networks. When the propagation delay is negligible, we show the starkly different scaling behavior of the minimum multihop delay in instantaneously connected networks as compared to networks that are only intermittently connected due to scarcity of spectrum opportunities. Specifically, if the network is instantaneously connected, the minimum multihop delay is asymptotically independent of the distance; if the network is only intermittently connected, the minimum multihop delay scales linearly with the distance. When the propagation delay is nonnegligible but small, we show that although the scaling order is always linear, the scaling rate for an instantaneously connected network can be orders of magnitude smaller than the one for an intermittently connected network.
The Impact of Media Bias: How Editorial Slant Affects Voters

We investigate how editorial slant—defined as the quantity and tone of a newspaper's candidate coverage as influenced by its editorial position—shapes candidate evaluations and vote choice. We avoid various methodological pitfalls by focusing on a single Senate campaign in a single market with two competing, editorially distinct newspapers. Combining comprehensive content analyses of the papers with an Election Day exit poll, we assess the slant of campaign coverage and its effects on voters. We find compelling evidence that editorial slant influences voters’ decisions. Our results raise serious questions about the media's place in democratic processes.
Does Component Sharing Help or Hurt Reliability? An Empirical Study in the Automotive Industry

Component sharing---the use of a component on multiple products within a firm's product line---is widely practiced as a means of offering high variety at low cost. Although many researchers have examined trade-offs involved in component sharing, little research has focused on the impact of component sharing on quality. In this paper, we examine how component sharing impacts one dimension of quality---reliability---defined as mean time to failure. Design considerations suggest that a component designed uniquely for a product will result in higher reliability due to the better fit of the component within the architecture of the product. On the other hand, the learning curve literature suggests that greater experience with a component can improve conformance quality, and can increase reliability via learning from end-user feedback. The engineering literature suggests that improved conformance in turn increases reliability. Sharing a component across multiple products increases experience, and hence, should increase reliability. Using data from the automotive industry, we find support for the hypothesis that higher component reliability is associated with higher cumulative experience with a component. Further, we find support for the hypothesis that higher component reliability is associated with a component that has been designed uniquely for a product. This finding suggests that the popular design strategy of component sharing can in some cases compromise product quality, via reduced reliability.
A novel hybridization of higher order finite element and boundary integral methods for electromagnetic scattering and radiation problems

A novel hybridization of the finite element and boundary integral methods is presented for an efficient and accurate numerical analysis of electromagnetic scattering and radiation problems. The proposed method derives an adaptive numerical absorbing boundary condition (ABC) for the finite element solution based on boundary integral equations. Unlike the standard finite element boundary integral (FE BI) approach, the proposed method is free of interior resonance and produces a purely sparse system matrix, which can be solved very efficiently. Unlike the traditional finite element absorbing boundary condition (FE ABC) approach, the proposed method uses an arbitrarily-shaped truncation boundary placed very close to the scatterer/radiator to minimize the computational domain and more importantly, produce a solution that converges to the true solution of the problem.
Diversity-multiplexing tradeoff of network coding with bidirectional random relaying

This paper develops a diversity-multiplexing tradeoff (DMT) over a bidirectional random relay set in a wireless network where the distribution of all nodes is a stationary Poisson point process. This is a nontrivial extension of the DMT because it requires consideration of the cooperation (or lack thereof) of relay nodes, the traffic pattern and the time allocation between the forward and reverse traffic directions. We then use this tradeoff to compare the DMTs of traditional time-division multihop (TDMH) and network coding (NC). Our main results are the derivations of the DMT for both TDMH and NC. This shows, surprisingly, that if relay nodes collaborate NC does not always have a better DMT than TDMH since it is difficult to simultaneously achieve bidirectional transmit diversity for both source nodes. In fact, for certain traffic patterns NC can have a worse DMT due to suboptimal time allocation between the forward and reverse transmission directions.
Self-Protection, Strategic Interactions, and the Relative Endogeneity of Disease Risks

Self‐protection is a key behavior that influences infectious disease risks. Spillovers in disease protection create different types of strategic interactions. Under certain conditions, multiple Nash equilibria may arise with the possibility of coordination failure involving excessively low self‐protection, in which case individuals’ expectations of others’ efforts determine which outcome arises. In prior studies, assumed technical relations between self‐protection and infection probabilities drove the strategic interactions. We demonstrate that strategic relations can be endogenously determined and depend on the relative endogeneity of risk (RER), defined here as the degree to which individuals can take control of their own risks in a strategic setting. The potential for coordination failure may arise when RER is sufficiently small, whereas larger levels of RER may eliminate this possibility to ensure larger levels of self‐protection. We find that imposing a behaviorally‐dependent indemnity may increase RER to eliminate the possibility of coordination failure. We apply our analysis to the problem of livestock disease and illustrate the theory using a numerical example of the 2001 United Kingdom foot‐and‐mouth disease epidemic.
Corporate competition: A self-organized network

A substantial number of studies have extended the work on universal properties in physical systems to complex networks in social, biological, and technological systems. In this paper, we present a complex networks perspective on interfirm organizational networks by mapping, analyzing and modeling the spatial structure of a large interfirm competition network across a variety of sectors and industries within the United States. We propose two micro-dynamic models that are able to reproduce empirically observed characteristics of competition networks as a natural outcome of a minimal set of general mechanisms governing the formation of competition networks. Both models, which utilize different approaches yet apply common principles to network formation give comparable results. There is an asymmetry between companies that are considered competitors, and companies that consider others as their competitors. All companies only consider a small number of other companies as competitors; however, there are a few companies that are considered as competitors by many others. Geographically, the density of corporate headquarters strongly correlates with local population density, and the probability two firms are competitors declines with geographic distance. We construct these properties by growing a corporate network with competitive links using random incorporations modulated by population density and geographic distance. Our new analysis, methodology and empirical results are relevant to various phenomena of social and market behavior, and have implications to research fields such as economic geography, economic sociology, and regional economic development.
Linguistic Cues Enhance the Learning of Perceptual Cues

When language is correlated with regularities in the world, does it enhance the learning of these regularities? This question lies at the core of both notions of linguistic bootstrapping in children and the Whorfian hypothesis. Support for an affirmative answer is provided in an artificial-noun-learning task in which 2-year-old children were taught to distinguish categories of solid and nonsolid things with and without supporting correlated linguistic cues.
A Comparison of Reducing and Oxidizing Heat Treatments of Hot‐Pressed Silicon Nitride

The effects of postfabrication heat treatments in argon and air atmospheres at 1400°C on the microstructure of a hot-pressed silicon nitride are compared. Heating in argon leads to a disappearance of the intergranular glass phase (with the consequent formation of interconnected porosity) and a reduction in the content of silicon oxynitride, and results in a soft, easily abraded surface. On subsequent heating in air, an oxide scale, similar to that produced by oxidation, rich in impurity and additive cations, is formed on the surface. In addition, silicon oxynitride and silica are formed below the scale. On cooling, macroscopic cracking, attributed to the volume increase of SO2 on transformation to cristobalite, occurs. Material heated first in air and then in argon resembled that of material heated in argon alone.
Agnostic learning of disjunctions on symmetric distributions

We consider the problem of approximating and learning disjunctions (or equivalently, conjunctions) on symmetric distributions over {0; 1}n. Symmetric distributions are distributions whose PDF is invariant under any permutation of the variables. We prove that for every symmetric distribution D, there exists a set of nO(log (1/e)) functions S, such that for every disjunction c, there is function p, expressible as a linear combination of functions in S, such that p e-approximates c in l1 distance on D or Ex-D[|c(x) - p(x)|] ≤ e. This implies an agnostic learning algorithm for disjunctions on symmetric distributions that runs in time nO(log (1/e)). The best known previous bound is nO(1/e4) and follows from approximation of the more general class of halfspaces (Wimmer, 2010). We also show that there exists a symmetric distribution D, such that the minimum degree of a polynomial that 1/3-approximates the disjunction of all n variables in l1 distance on D is Ω(√n). Therefore the learning result above cannot be achieved via l1-regression with a polynomial basis used in most other agnostic learning algorithms. Our technique also gives a simple proof that for any product distribution D and every disjunction c, there exists a polynomial p of degree O(log (1/e)) such that p e-approximates c in l1 distance on D. This was first proved by Blais et al. (2008) via a more involved argument.
Time-dependent model of aseismic slip on the central San Andreas Fault from InSAR time series and repeating earthquakes

The Central segment of San Andreas Fault (CSAF) is characterized by a nearly continuous right-lateral aseismic slip. However, observations of the creep rate obtained using small characteristically repeating earthquakes (CREs) show pulses of creep along the CSAF, which may indicate spatially and temporally variable seismic hazard along the CSAF. Therefore, the goal of this study is to obtain a high-resolution time-dependent model of creep along the CSAF to examine this hypothesis. To this end, we apply a time-dependent creep modeling approach, which combines interferometric synthetic aperture radar (InSAR) surface deformation time series and observations of fault creep obtained from CREs. The SAR data set includes C band scenes acquired by the ERS-2 and Envisat satellites between 2003 and 2011. The resulting creep rate distribution implies a peak rate up to 32 mm/yr along the central part of the CSAF. Afterslip due to the 2004 Parkfield earthquake on the southeastern segment of the CSAF is also manifest in the model, and there is clear evidence of creep pulsing along strike and depth of the CSAF. Estimated annual rate of slip deficit accumulation is equivalent to a magnitude 5.6–5.7 earthquake. Taking advantage of the time-dependence of our model, we also refine the scaling relationship, which associates the released seismic moment due to a CRE event with the amount of creep on the fault, surrounding the CRE patches. This study provides the first kinematic model of creep pulsing, constrained using geodetic and seismic data, which can enhance time-dependent seismic hazard maps and improve earthquake operational forecast models.
Welfare implications of net social security wealth

Real net social wealth (NSSW), the real present value of social security benefits received minus social security taxes paid, is frequently used as a direct proxy measure for the impact of a social security system on generation welfare. The present paper establishes to the contrary, for a class of overlapping generation economies, that NSSW can be simultaneously negatively correlated with welfare for every agent in every generation. More generally, the paper determines the extent to which social security is needed in these economies to ensure social optimality, and investigates the proper subset of economies for which NSSW and generation welfare exhibit positive correlation.
Sensitive White Space Detection with Spectral Covariance Sensing

This paper proposes a novel, highly effective spectrum sensing algorithm for cognitive radio and white space applications. The proposed spectral covariance sensing (SCS) algorithm exploits the different statistical correlations of the received signal and noise in the frequency domain. Test statistics are computed from the covariance matrix of a partial spectrogram and compared with a decision threshold to determine whether a primary signal or arbitrary type is present or not. This detector is analyzed theoretically and verified through realistic open-source simulations using actual digital television signals captured in the US. Compared to the state of the art in the literature, SCS improves sensitivity by 3 dB for the same dwell time, which is a very significant improvement for this application. Further, it is shown that SCS is highly robust to noise uncertainty, whereas many other spectrum sensors are not.
How Opportunity Costs Decrease the Probability of War in an Incomplete Information Game

This paper shows that the opportunity costs resulting from economic interdependence decrease the equilibrium probability of war in an incomplete information game. This result is strongly consistent with existing empirical analyses of the inverse trade-conflict relationship, but is the opposite of the conclusion reached by Gartzke et al. (2001), who reject the opportunity cost argument in a game-theoretic framework. As a result of this paper’s findings, one cannot dismiss the opportunity cost argument as the explanation why trading nations fight less. Instead this study reaffirms the central position of opportunity costs as the basis for the inverse trade-conflict relationship, thus implying that one need not rely on signaling.
Conjugacy classes and characters for extensions of finite groups

Let H be an extension of a finite group Q by a finite group G. Inspired by the results of duality theorems for etale gerbes on orbifolds, the authors describe the number of conjugacy classes of H that map to the same conjugacy class of Q. Furthermore, a generalization of the orthogonality relation between characters of G is proved.
Mismatch sensitivity of a simultaneously latched CMOS sense amplifier

Derives a new formula for the sensitivity of a vertically matched CMOS sense amplifier, of the type used in dynamic-RAMs (DRAMs), to threshold voltage mismatch, parasitic capacitance mismatch, transconductance mismatch, and bit-line load capacitance mismatch. The formula yields insight into the DRAM sensing operation. The authors derive a sensitivity formula for this sensing scheme, using perturbation theory. The perturbation approach is rigorous: it avoids most approximations and ad-hoc assumptions, it introduces no free constants to be determined from simulations, and it yields an explicit closed-form solution. The formula agrees well with simulations. It is inherently slightly conservative and thus appropriate for use in design. >
Unconscious Racism: A Concept in Pursuit of a Measure

It is common in scientific and popular discussions to claim that unconscious racism is both prevalent and potent in modern societies. We review the theoretical models that posit different forms of unconscious racism and evaluate the empirical evidence for them. Our analysis suggests that people may sometimes lack knowledge of and control over the causes and consequences of their racial biases. However, there is little evidence to support the more provocative claim: that people possess unconscious racist attitudes. Many of the arguments to the contrary rest on strong interpretations of response patterns on implicit attitude measures. Although advances in implicit measurement can improve our understanding of racial bias, at present their use as tools for rooting out unconscious racism is limited. We describe research programs that might move these constructs to firmer scientific footing, and we urge inferential caution until such research programs are carried out.
Pattern avoidance in set partitions

The study of patterns in permutations is a very active area of current research. Klazar dened and studied an analogous notion of pattern for set partitions. We continue this work, nding exact formulas for the number of set partitions which avoid certain specic patterns. In particular, we enumerate and characterize those partitions avoiding any partition of a 3-element set. This allows us to conclude that the corresponding sequences are P-recursive. Finally, we dene a second notion of pattern in a set partition, based on its restricted growth function. Related results are obtained for this new denition.
Interactive Multiobjective Optimization Procedure

This research focuses on multiobjective system design and optimization. The primary goal is to develop and test a mathematically rigorous and efficient interactive multiobjective optimization algorithm that takes into account the designer's preferences during the design process. In this research, an interactive multiobjective optimization procedure (IMOOP) that uses an aspiration-level approach to generate Pareto points is developed. This method provides the designer or the decision maker (DM) with a formal means for efficient design exploration around a given Pareto point. More specifically, the procedure provides the DM with the Pareto sensitivity information and the Pareto surface approximation at a given Pareto design for decision making and tradeoff analysis. The IMOOP has been successfully applied to two test problems. The first problem consists of a set of simple analytical expressions for its objective and constraints. The second problem is the design and sizing of a high-performance and low-cost 10-bar structure that has multiple objectives. The results indicate that the Pareto designs predicted by the Pareto surface approximation are reasonable and the performance of the second-order approximation is superior compared to that of the first-order approximation. Using this procedure a set of new aspirations that reflect the DM's preferences are easily and efficiently generated, and the new Pareto design corresponding to these aspirations is close to the aspirations themselves. This is important in that it builds the confidence of the DM in this interactive procedure for obtaining a satisfactory final Pareto design in a minimal number of iterations.
High-speed wide-locking range VCO with frequency calibration

High-speed network systems require a wide-frequency-range clock system for data processing. Frequency calibration method enables the voltage-controlled oscillator (VCO) in a phase-locked loop (PLL) to cover the expected frequency range for high-speed applications that require a wide locking range. Frequency range adjustment is implemented by means of a current DAC, which controls the current of an inverter chain oscillator. The circuit is implemented within small space in a high-speed hard disk drive channel with 0.25-/spl mu/m four-layer metal CMOS technology.
Palladium-catalyzed potassium enoxyborate alkylation of enantiopure Hajos-Parrish indenone to construct rearranged steroid ring systems.

Here we report the stereo- and regiospecific C-6 alkylation of a trans-inden-5-one (from optically pure Hajos−Parrish ketone) with allylic electrophiles. Use of this alkylation procedure has led to an improved synthesis of the benz[f]indene ring system and the first enantiospecific total syntheses of the cyclopenta[b]anthracene and cyclopenta[b]phenanthrene ring systems (two synthetic routes).
Let the Pirates Patch? An Economic Analysis of Software Security Patch Restrictions

We study the question of whether a software vendor should allow users of unlicensed (pirated) copies of a software product to apply security patches. We present a joint model of network software security and software piracy and contrast two policies that a software vendor can enforce: (i) restriction of security patches only to legitimate users or (ii) provision of access to security patches to all users whether their copies are licensed or not. We find that when the software security risk is high and the piracy enforcement level is low, or when tendency for piracy in the consumer population is high, it is optimal for the vendor to restrict unlicensed users from applying security patches. When piracy tendency in the consumer population is low, applying software security patch restrictions is optimal for the vendor only when the piracy enforcement level is high. If patching costs are sufficiently low, however, an unrestricted patch release policy maximizes vendor profits. We also show that the vendor can use security patch restrictions as a substitute to investment in software security, and this effect can significantly reduce welfare. Furthermore, in certain cases, increased piracy enforcement levels can actually hurt vendor profits. We also show that governments can increase social surplus and intellectual property protection simultaneously by increasing piracy enforcement and utilizing the strategic interaction of piracy patch restrictions and network security. Finally, we demonstrate that, although unrestricted patching can maximize welfare when the piracy enforcement level is low, contrary to what one might expect, when the piracy enforcement level is high, restricting security patches only to licensed users can be socially optimal.
Recovering device drivers

This article presents a new mechanism that enables applications to run correctly when device drivers fail. Because device drivers are the principal failing component in most systems, reducing driver-induced failures greatly improves overall reliability. Earlier work has shown that an operating system can survive driver failures lSwift et al. 2005r, but the applications that depend on them cannot. Thus, while operating system reliability was greatly improved, application reliability generally was not.To remedy this situation, we introduce a new operating system mechanism called a shadow driver. A shadow driver monitors device drivers and transparently recovers from driver failures. Moreover, it assumes the role of the failed driver during recovery. In this way, applications using the failed driver, as well as the kernel itself, continue to function as expected.We implemented shadow drivers for the Linux operating system and tested them on over a dozen device drivers. Our results show that applications and the OS can indeed survive the failure of a variety of device drivers. Moreover, shadow drivers impose minimal performance overhead. Lastly, they can be introduced with only modest changes to the OS kernel and with no changes at all to existing device drivers.
Note on volume effect in coiling molecules

An estimate of the magnitude of the interference effect in a coil-like molecule is made by calculating the nearest neighbor density w around a given link as a function of the total number of contributing chain units. It is shown, for instance, that in a chain consisting of several hundred units, the first fifteen contribute about 75 % of the total nearest neighbor density at distances below the length of a link. The plots presented indicate that after about the first twenty links, the rate of increase of nearest neighbor density begins to flatten off. It is also possible to derive the modification of the distribution function of chain ends in real chains for a given form of w.
A rationally designed universal catalyst for Suzuki-Miyaura coupling processes

Despite advances in the Suzuki–Miyaura cross-coupling process, the need for an operationally simple and general system remains. The minimum criteria for an optimum system that must be met include: 1) a broad substrate scope, 2) the ability to make truly hindered biaryls, 3) the ability to operate at low levels of catalyst for a range of substrates not just with the most simple examples (e.g., other than phenyl boronic acid), and 4) the ability to operate at room temperature. Moreover, it is most desirable to develop protocols that do not necessitate the use of a glovebox. Herein we report a catalyst system based on a new ligand that meets the above four criteria, has unprecedented scope, reactivity, and stability, uses only commercially available, air-stable components, and is experimentally simple to employ. Our previous work on cross-coupling methodology demonstrated that dialkylphosphanylbiphenyls were excellent supporting ligands. We have reported that these can be prepared by the addition of an aryl Grignard reagent to an insitu-generated benzyne intermediate, followed by trapping of the newly formed organomagnesium complex with ClPR2. [3] The thought process that led to the design of the new ligand 1 is shown in Scheme 1. Mechanistic studies in our laboratory indicated that the elimination of ortho hydrogens on the bottom ring (that not bearing the dialkylphosphanyl group) was important for catalyst activity and longevity. We believe that this is due to two effects: 1) prevention of cyclometalation (to form a palladacycle), which diminishes catalyst lifetime, and 2) increased steric bulk relative to complexes with two ortho hydrogens. We also feel that it is important that the two methoxy groups are smaller in size than two alkyl groups as in our previously reported ligands. Moreover, the lone pairs of the alkoxy groups might interact with the Pd center and/or add electron density to the ligand backbone. The latter could be important as the interaction of the metal with the bottom ring is well documented and could help stabilize intermediate complexes. Furthermore, the 1,3-dimethoxybenzene moiety offers the advantage that it can be installed by means
An argument in Metaphysics Z 13

In Metaphysics Z 13 Aristotle argues that no universal can be substance. Prima facie, this appears to rule out the possibility that any universal can be substance, species as well as genera. Nevertheless, many commentators have denied that this chapter intends to rule out the possibility that any universal can be substantial. Aristotle, it is thought, cannot wish to deny that any universal can be substance because he believes that some universals are substances, viz. species.
Application of intramolecular enyne metathesis to the synthesis of aza[4.2.1]bicyclics: enantiospecific total synthesis of (+)-anatoxin-a.

A concise synthesis of the potent nAChR agonist (+)-anatoxin-a (1) has been completed in a series of only nine chemical operations and 27% overall yield from commercially available d-methyl pyroglutamate (4). The synthesis features a novel procedure for the diastereoselective preparation of cis-2,5-disubstituted pyrrolidines leading to 10, which underwent an intramolecular enyne metathesis to afford a bridged azabicyclic intermediate that was transformed into 1.
Photoelectron Spectroscopy of Lanthanide−Silicon Cluster Anions LnSin− (3 ≤ n ≤ 13; Ln = Ho, Gd, Pr, Sm, Eu, Yb): Prospect for Magnetic Silicon-Based Clusters

Photoelectron spectroscopy was utilized to study a variety of LnSin− cluster anions (Ln = Yb, Eu, Sm, Gd, Ho, Pr; 3 ≤ n ≤ 13). For a particular size n, the measured valence electronic transitions of all these systems fall into either one of two categories, reflecting the influence of the different oxidation states of the lanthanide atoms involved. In one, the spectra of YbSin− and EuSin− are nearly identical to each other, while in the other the spectra of GdSin−, HoSin−, and PrSin− are essentially identical. SmSin− clusters exhibit an intermediate behavior with smaller clusters resembling the former category and larger clusters resembling the latter category. In the intermediate size range, 7 ≤ n ≤ 10, for SmSin− both categories appear to be present, with one matching the EuSin−-like systems and the other HoSin−-like clusters. The distinction between LnSin− categories strongly correlates with the oxidation state of the particular lanthanide as usually found in its compounds. On the basis of this observat...
Smooth distributions are finitely generated

A subbundle of variable dimension inside the tangent bundle of a smooth manifold is called a smooth distribution if it is the pointwise span of a family of smooth vector fields. We prove that all such distributions are finitely generated, meaning that the family may be taken to be a finite collection. Further, we show that the space of smooth sections of such distributions need not be finitely generated as a module over the smooth functions. Our results are valid in greater generality, where the tangent bundle may be replaced by an arbitrary vector bundle.
Suppression of Gonadotropins and Estradiol in Premenopausal Women by Oral Administration of the Nonpeptide Gonadotropin-Releasing Hormone Antagonist Elagolix

Context: Parenteral administration of peptide GnRH analogs is widely employed for treatment of endometriosis and fibroids and in assisted-reproductive therapy protocols. Elagolix is a novel, orally available nonpeptide GnRH antagonist. Objective: Our objective was to evaluate the safety, pharmacokinetics, and inhibitory effects on gonadotropins and estradiol of single-dose and 7-d elagolix administration to healthy premenopausal women. Design: This was a first-in-human, double-blind, placebo-controlled, single- and multiple-dose study with sequential dose escalation. Participants: Fifty-five healthy, regularly cycling premenopausal women participated. Interventions: Subjects were administered a single oral dose of 25–400 mg or placebo. In a second arm of the study, subjects received placebo or 50, 100, or 200 mg once daily or 100 mg twice daily for 7 d. Treatment was initiated on d 7 (±1) after onset of menses. Main Outcome Measures: Safety, tolerability, pharmacokinetics, and serum LH, FSH, and estradiol concentrations were assessed. Results: Elagolix was well tolerated and rapidly bioavailable after oral administration. Serum gonadotropins declined rapidly. Estradiol was suppressed by 24 h in subjects receiving at least 50 mg/d. Daily (50–200 mg) or twice-daily (100 mg) administration for 7 d maintained low estradiol levels (17 ± 3 to 68 ± 46 pg/ml) in most subjects during late follicular phase. Effects of the compound were rapidly reversed after discontinuation. Conclusions: Oral administration of a nonpeptide GnRH antagonist, elagolix, suppressed the reproductive endocrine axis in healthy premenopausal women. These results suggest that elagolix may enable dose-related pituitary and gonadal suppression in premenopausal women as part of treatment strategies for reproductive hormone-dependent disease states.
The First Examples of a Meta-Benzannulation from the Reaction of Fischer Carbene Complexes with Alkynes

The intramolecular benzannulations of carbene complexes with alkynes are examined where the alkyne is tethered to the α-carbon of the vinyl carbene complex. These reactions are sensitive to the length of the tether and to the nature of the solvent. With a tether length of 16 methylenes, the reaction occurs in the same fashion as the intermolecular reactions to give a p-cyclophane. With intermediate tether lengths (n = 10, 13), the reaction gives an additional p-cyclophane in which the two oxygen substituents are meta on the arene ring. This type of product is unprecedented from the reaction of carbene complexes and alkynes and is quite surprising because the formation of this product requires that the carbon−carbon bond between the α- and β-carbons of the vinyl carbene complex is broken. A mechanism is proposed to account for this process which involves the crossed intramolecular [2 + 2] cycloaddition of the alkene and a ketene in a conjugated dienyl ketene to give a benzvalenone paddalane intermediate.