cssi/SciSciGPT-SciSciNet huggingface dataset:
GKMPAN: An Efficient Group Rekeying Scheme for Secure Multicast in Ad-Hoc Networks

We present GKMPAN, an efficient and scalable group rekeying protocol for secure multicast in ad hoc networks. Our protocol exploits the property of ad hoc networks that each member of a group is both a host and a router, and distributes the group key to member nodes via a secure hop-by-hop propagation scheme. A probabilistic scheme based on pre-deployed symmetric keys is used for implementing secure channels between members for group key distribution. GKMPAN also includes a novel distributed scheme for efficiently updating the pre-deployed keys. GKMPAN has three attractive properties. First, it is significantly more efficient than group rekeying schemes that were adapted from those proposed for wired networks. Second, GKMPAN has the property of partial statelessness; that is, a node can decode the current group key even if it has missed a certain number of previous group rekeying operations. This makes it very attractive for ad hoc networks where nodes may lose packets due to transmission link errors or temporary network partitions. Third, in GKMPAN the key server does not need any information about the topology of the ad hoc network or the geographic location of the members of the group. We study the security and performance of GKMPAN through detailed analysis and simulation; we have also implemented GKMPAN in a sensor network testbed.
Error Exponents and Cutoff Rate for Noncoherent Rician Fading Channels

In this paper, random coding error exponents and cutoff rate are studied for noncoherent Rician fading channels, where neither the receiver nor the transmitter has channel side information. First, it is assumed that the input is subject only to an average power constraint. In this case, a lower bound to the random coding error exponent is considered and the optimal input achieving this lower bound is shown to have a discrete amplitude and uniform phase. If the input is subject to both average and peak power constraints, it is proven that the optimal input achieving the random coding error exponent has again a discrete nature. Finally, the cutoff rate is analyzed, and the optimality of the single-mass input amplitude distribution in the low-power regime is discussed.
Analyzing factors affecting U.S. food price inflation.

Since the summer of 2007, U.S. food price inflation has increased dramatically. Given public anxiety over fast-rising food prices, this study attempts to analyze the effects of market factors—prices of energy and agricultural commodities and exchange rate—on U.S. food prices using a cointegration analysis. Results show that the agricultural commodity price and exchange rate play the key roles in determining the short- and long-run movement of U.S. food prices. It is also found that in recent years, energy price has been a significant factor affecting U.S. food prices in the long run, but has little effect in the short run. This implies the strong linkage between energy and agricultural markets in the long run over the recent years. Depuis l’ete 2007, l’inflation des prix des aliments aux Etats-Unis a augmente considerablement. En raison de l’anxiete que la hausse rapide des prix des aliments suscite au sein de la population, nous avons tente d’evaluer, a l’aide d’une analyse de co-integration, les repercussions de certains facteurs de marche– le prix de l’energie, le prix des produits agricoles primaires et le taux change – sur les prix des aliments aux Etats-Unis. Les resultats ont montre que les prix des produits agricoles primaires et le taux de change jouent un role important dans la determination des tendances a court et a long terme des prix des aliments aux Etats-Unis. Nous avons egalement constate que, au cours des dernieres annees, le prix de l’energie a eu une forte influence sur les prix des aliments aux Etats-Unis a long terme, mais peu d’influence a court terme. Cette observation montre l’etroit lien a long terme des marches de l’energie et des produits agricoles au cours des dernieres annees.
Automating the Design and Construction of Query Forms

One of the simplest ways to query a database is through a form where a user can fill in relevant information and obtain desired results by submitting the form. Designing good forms is a nontrivial manual task, and the designer needs a sound understanding of both the data organization and the querying needs. Furthermore, form design usually has conflicting goals: each form should be simple and easy to understand, while collectively, the interface must support as many queries as possible. In this paper, we present a framework for generating forms in an automatic and principled way, given a database and a sample query workload. We design a tunable clustering algorithm for establishing form structure based on multiple "similar" queries, which includes a mechanism for extending forms to support future "similar" queries. The algorithm is adaptive and can incrementally adjust forms to reflect the most current querying trends. We have implemented our form generation system on a real database and evaluated it on a comprehensive set of query loads and database schemas. We observe that our system generates a modest number of forms for large and diverse query loads even after placing a strict bound on form complexity.
Feedback Effects and Asset Prices

Feedback effects from asset prices to firm cash flows have been empirically documented. This finding raises a question for asset pricing: How are asset prices determined if price affects fundamental value, which in turn affects price? In this environment, by buying assets that others are buying, investors ensure high future cash flows for the firm and subsequent high returns for themselves. Hence, investors have an incentive to coordinate, which may generate self-fulfilling beliefs and multiple equilibria. Using insights from global games, we pin down investors' beliefs, analyze equilibrium prices, and show that strong feedback leads to higher excess volatility.
The Role of Politics in Economic Development

How have economic historians understood the role of politics in shaping country differences in economic development? An impressive recent literature can be sorted out according to the degree of “human agency” at work. At the low-agency end are perspectives that stress geography, which is unalterable, leaving little room for human action and hence no room for politics. At the other end are arguments stressing deliberate, self-aware actions, hence choice, hence a substantial role for politics. In between are arguments where some choice occurred in the past or at a specific moment, but little since then. What drives development? Two lines of argument are vigorously debated: explanations that stress human capital and explanations that stress institutions. Within each camp can be found variance on the degree of agency and hence on the role of politics. Both vary as well on how they envisage society and its interaction with both institutions and human capital.
Public Opinion and Senate Confirmation of Supreme Court Nominees

Does public opinion influence Supreme Court confirmation politics? We present the first direct evidence that state-level public opinion on whether a particular Supreme Court nominee should be confirmed affects the roll-call votes of senators. Using national polls and applying recent advances in opinion estimation, we produce state-of-the-art estimates of public support for the confirmation of 10 recent Supreme Court nominees in all 50 states. We find that greater home-state public support does significantly and strikingly increase the probability that a senator will vote to approve a nominee, even controlling for other predictors of roll-call voting. These results establish a systematic and powerful link between constituency opinion and voting on Supreme Court nominees. We connect this finding to larger debates on the role of majoritarianism and representation.
A self consistent generalized model for the calculation of minor loop excursions in the theory of hysteresis

The author describes a generalization of the theory of hysteresis to cover asymmetric or minor hysteresis loop excursions. The original description of the model was found to be particularly useful because it enabled hysteresis loops of magnetic materials to be successfully modeled with a limited set of only five physically based parameters. The extension of the model presented is completely self-consistent with the original formulation and requires no additional parameters to describe the minor loops. Results of the model calculations are shown with the objective of demonstrating the morphology of the solutions. These display the expected behavior and also include the phenomena of minor loop crossing the partial coincidence of minor loops under certain conditions. >
Thermodynamic anomaly of the free damped quantum particle: the bath perspective

A possible definition of the specific heat of open quantum systems is based on the reduced partition function of the system. For a free damped quantum particle, it has been found that under certain conditions, this specific heat can become negative at low temperatures. In contrast to the conventional approaches focusing on the system degree of freedom, here we concentrate on the changes induced in the environment when the system is coupled to it. Our analysis is carried out for an Ohmic environment consisting of harmonic oscillators and allows to identify the mechanism by which the specific heat becomes negative. Furthermore, the formal condition for the occurrence of a negative specific heat is given a physical interpretation in terms of the total mass of bath oscillators and the system mass.
Some Remarks on the Hyperelliptic Moduli of Genus 3

In 1967, Shioda [20] determined the ring of invariants of binary octavics and their syzygies using the symbolic method. We discover that the syzygies determined in [20] are incorrect. In this paper, we compute the correct equations among the invariants of the binary octavics and give necessary and sufficient conditions for two genus 3 hyperelliptic curves to be isomorphic over an algebraically closed field k, char k ≠ 2, 3, 5, 7. For the first time, an explicit equation of the hyperelliptic moduli for genus 3 is computed in terms of absolute invariants.
Subjective Probability Assessment in Decision Analysis: Partition Dependence and Bias Toward the Ignorance Prior

Decision and risk analysts have considerable discretion in designing procedures for eliciting subjective probabilities. One of the most popular approaches is to specify a particular set of exclusive and exhaustive events for which the assessor provides such judgments. We show that assessed probabilities are systematically biased toward a uniform distribution over all events into which the relevant state space happens to be partitioned, so that probabilities are "partition dependent." We surmise that a typical assessor begins with an "ignorance prior" distribution that assigns equal probabilities to all specified events, then adjusts those probabilities insufficiently to reflect his or her beliefs concerning how the likelihoods of the events differ. In five studies, we demonstrate partition dependence for both discrete events and continuous variables (Studies 1 and 2), show that the bias decreases with increased domain knowledge (Studies 3 and 4), and that top experts in decision analysis are susceptible to this bias (Study 5). We relate our work to previous research on the "pruning bias" in fault-tree assessment (e.g., Fischhoff et al. 1978) and show that previous explanations of pruning bias (enhanced availability of events that are explicitly specified, ambiguity in interpreting event categories, and demand effects) cannot fully account for partition dependence. We conclude by discussing implications for decision analysis practice.
Conceptual and contextual DNA-based memory

DNA memories have the potential not only to store a vast amount of information with high density, but also may be able to process the stored information through laboratory protocols that match content and context. This might lead to knowledge mining applications on a massively parallel scale, and to a limited capability for intelligent processing of stored data to discover semantic information. In this paper, a design for such a DNA memory is presented.
Catalysis of Mukaiyama Aldol Reactions by a Tricyclic Aluminum Alkoxide Lewis Acid

The Mukayiama aldol reaction of aldehydes is efficiently accomplished with a low concentration of the dimeric alumatrane catalyst 2 at mild or subambient temperatures. Our protocol tolerates a wide variety of electron-rich, neutral, and deficient aryl, alkyl, and heterocyclic aldehydes. A wide variety of enol silyl ethers are also tolerated. An intermediate that was isolated provides mechanistic information regarding the role of dimeric 2 in the Mukaiyama aldol reaction. Experimental evidence is presented for the stronger Lewis acidity of 5 compared with F3B.
Concepts Structured Through Reduction: A Structuralist Resource Illuminates The Consolidation – Long-Term Potentiation (Ltp) Link

The structuralist program has developed a useful metascientific resource: ontological reductive links (ORLs) between the constituents of the potential models of reduced and reducing theories. This resource was developed initially to overcome an objection to structuralist ``global'' accounts of the intertheoretic reduction relation. But it also illuminates the way that concepts at a higher level of scientific investigation (e.g., cognitive psychology) become ``structured through reduction'' to lower-level investigations (e.g., cellular/molecular neuroscience). After (briefly) explaining this structuralist background, I demonstrate how this resource illuminates an actual, emerging scientific example: the link between the psychological concept of a ``consolidation switch'' from short-term to long-term memory and the cellular/molecular mechanisms of the transition from early- to late-phases of long-term potentiation (LTP) (an important type of synaptic plasticity in mammalian hippocampus and cortex).
Trade Policy Instruments over Time

This paper surveys political-economic research on the variety of instruments that governments use to conduct international trade policy. It presents key insights on the relationships between instruments such as tariffs, quotas, voluntary export restraints, and other nontariff barriers, as well as the ebb and flow of the national use of temporary trade barriers such as antidumping, countervailing duties, and safeguards. The survey examines trends in use of these trade policy instruments over recent history; and it reviews the major theoretical and empirical explanations behind, and interrelationships between, their uses. Finally, the paper highlights potential institutional impacts of the General Agreement on Tariffs and Trade (GATT) and subsequent World Trade Organization (WTO) on choice of policy instruments, as well as how multilateral, unilateral, and preferential tariff liberalization may introduce political-economic shocks and affect incentives over time for how governments rely on different instruments.
America's exhausted paradigm: Macroeconomic causes of the financial crisis and great recession

This paper traces the roots of the financial crisis and Great Recession to a flawed U.S. macroeconomic paradigm that was adopted around 1980 with the triumph of neoliberal economics. One flaw concerns the growth model. A second flaw concerns the model of global economic engagement that created a triple economic hemorrhage of spending on imports, manufacturing job losses, and off-shoring of investment. The new growth model hollowed out the economy and relied on growing debt and asset price inflation. As the process deepened the economy needed ever larger bubbles to grow. Financial deregulation and excess kept the model going longer than expected, but it meant the economy experienced a financial crash and deeper collapse when the contradictions finally surfaced. The United States needs a new economic paradigm and a new growth model, but as yet this challenge has received little attention from policymakers or economists.
Proton and Carbon-13 NMR Studies of Steroids and Triterpenes

Steroids and triterpenes are common constituents of higher and lower plants, as well as marine flora and fauna. Derived from mevalonic acid with squalene as an intermediate, their skeletal diversity is essentially unmatched. Some of these compounds are important as mammalian hormones (testosterone, estrone), while others are potent toxic agents either as molluscicides, insecticides or as cytotoxic agents. Thus, as well as chemical diversity, these compounds also represent biological diversity in their mode of action. Some of the compounds, for example beta-sitosterol, are probably almost ubiquitous in the plant kingdom, indicating that while there may be many selective biosynthetic pathways depending on a particular taxonomic and ecologic niche, there is also a pathway which may be primordial in nature remaining unchanged and common to all plants.
Cognitive Behavioral Treatment Outcomes in Adolescent ADHD

Objective: To assess the efficacy of cognitive behavioral therapy (CBT) for managing adolescent ADHD. Method: A total of 68 adolescents with ADHD and associated psychiatric comorbidities completed a manualized CBT treatment protocol. The intervention used in the study was a downward extension of the Safren et al. program for adults with ADHD who have symptoms unresolved by medication. Outcome variables consisted of narrow band (ADHD) and broadband (e.g., mood, anxiety, conduct) symptom measures (Behavior Assessment System for Children–2nd edition and ADHD–Rating Scales) as well as functioning measures (parent/teacher ratings and several ecologically real-world measures). Results: Treatment effects emerged on the medication dosage, parent rating of pharmacotherapy adherence, adolescent self-report of personal adjustment (e.g., self-esteem), parent and teacher ratings of inattentive symptoms, school attendance, school tardiness, parent report of peer, family and academic functioning and teacher report of ad...
Reconciling Domestication Techniques, the Notion of Re-exports and Some Comments on Regional Accounting

Recent work by Jackson (1998) subtly pointed out a means of forming direct input coefficient matrices from national technology that is different from that published elsewhere. In this paper, I rationalize his approach and also point out that prior approaches may still be useful in certain applications where the phenomenon of re-exports (imports that satisfy exports) are explicit in exports accounts. In the second half of this paper, I show some means of developing regional accounts, currently being used in the US, that are more elaborate than those Jackson discussed. For example, I substitute regional shares of employment with earnings shares to obtain productivity adjusted regional output. I also suggest using available regional value added and regional labour income when producing regional Use matrices.
A Monolithically-Integrated Optical Receiver in Standard 45-nm SOI

Integrated photonics has emerged as an I/O technology that can meet the throughput demands of future many-core processors. Taking advantage of the low capacitance environment provided by monolithic integration, we developed an integrating receiver front-end built directly into a clocked comparator, achieving high sensitivity and energy-efficiency. A simple model of the receiver provides intuition on the effects of wiring and photodiode capacitance, and leads to a photodiode-splitting technique enabling improved sensitivity at higher data rates. The receiver is characterized in situ and shown to operate with μA-sensitivity at 3.5 Gb/s with a power consumption of 180 μ W (52 fJ/bit) and area of 108 μm2 . This work demonstrates that photonics and electronics can be jointly integrated in a standard 45-nm SOI process.
Measurement of a 2-meter flat using a pentaprism scanning system

Precise manufacturing of optical flats requires precise characterization of the surface. A scanning pentaprism system is ideal for use as an absolute and precise test for an optical flat. Such a system was built and used to test a 2-m diameter flat mirror. This system uses light from an autocollimator that is reflected from two pentaprisms to project reference beams of light onto the flat mirror. The light reflected from the mirror back through the pentaprisms provides information on low order optical aberrations in the flat mirror. We report results of the test on a 2-m flat, characterizing the errors and their sources. There is enormous potential for our system to be used to test larger flats and even curved surfaces, made of either a glass or a liquid.
A model category structure on the category of simplicial categories

In this paper we put a cofibrantly generated model category struc- ture on the category of small simplicial categories. The weak equivalences are a simplicial analogue of the notion of equivalence of categories.
THE EFFECTS OF PHOTON BUBBLE INSTABILITY IN RADIATION-DOMINATED ACCRETION DISKS

We examine the effects of photon bubble instability in radiation-dominated accretion disks such as those found around black holes in active galactic nuclei and X-ray binary star systems. Two- and three-dimensional numerical radiation MHD calculations of small patches of disk are used. Modes with wavelengths shorter than the gas pressure scale height grow faster than the orbital frequency in the disk surface layers. The fastest growth rate observed is 5 times the orbital frequency and occurs on nearly vertical magnetic fields. The spectrum of linear modes is in good agreement with a WKB analysis that indicates still faster growth at unresolved scales, with a maximum growth rate proportional to the gravitational acceleration and inversely proportional to the gas sound speed. Disturbances reaching nonlinear amplitudes steepen into trains of shocks similar to a one-dimensional periodic nonlinear analytic solution. Variations in propagation speed result in merging of adjacent fronts, and over time the shock spacing and amplitude increase. Growth is limited by the strength of the magnetic field. The shock train structure is disrupted when the ram pressure of the disturbances exceeds the magnetic pressure. The maximum horizontal density variations are comparable to the ratio of magnetic to gas pressure and in our calculations exceed 100. Under the conditions considered, radiation diffuses through the inhomogeneneous flow 5 times faster than through the initial hydrostatic equilibrium, and the net cooling rate is several times greater than in a similar calculation without magnetic fields that shows the effects of convection. These results indicate that photon bubbles may be important in cooling radiation-dominated accretion disks. The Shaviv type I global instability grows faster than the orbital frequency in calculations of the disk surface layers with lower boundaries of fixed temperature, but is weak or absent in calculations spanning the disk thickness.
Non-Abelian Finite Gauge Theories

We study orbifolds of N = 4 U(n) super-Yang-Mills theory given by discrete subgroups of SU(2) and SU(3). We have reached many interesting observations that have graph-theoretic interpretations. For the subgroups of SU(2), we have shown how the matter content agrees with current quiver theories and have offered a possible explanation. In the case of SU(3) we have constructed a catalogue of candidates for finite (chiral) N = 1 theories, giving the gauge group and matter content. Finally, we conjecture a McKay-type correspondence for Gorenstein singularities in dimension 3 with modular invariants of WZW conformal models. This implies a connection between a class of finite N = 1 supersymmetric gauge theories in four dimensions and the classification of affine SU(3) modular invariant partition functions in two dimensions.
Development and Validation of the Academic Competence Evaluation Scales

The purpose of this study was to clarify the construct of academic competence and develop a valid teacher rating instrument to assess this construct. A 95-item pilot scale, the Academic Competence Evaluation Scales (ACES), was developed to assess the theoretical components (i.e., academic skills, study skills, academic motivation, interpersonal skills, and academic self-concept) hypothesized to contribute to the construct of academic competence. The ACES was administered to 56 teachers who rated 300 students in Grades 1 through 6. To explore convergent and discriminant validity, 13 teachers completed ratings of social skills, problem behaviors, and academic competence (as measured by the Social Skills Rating System; SSRS) for 60 students. In addition, 32 students completed the Iowa Test of Basic Skills (ITBS), a popular measure of academic achievement. Teacher feedback, item Importance ratings, item-ITBS correlations, and the results of an exploratory factor analysis were used to eliminate 35 items from t...
Reaching the masses through a Rural Services Platform

The richness of interaction technologies used by a consumer or moderated by a facilitator for the consumer plays an important role in adoption of financial, advisory and business services by a rural populace. Rural ICT initiatives undertaken so far have focused on device-level technologies that bring in a single service to the consumer. In this paper, we present the architecture and implementation of a Rural Services Platform which is not only a low cost shared model, but also brings in innovation in an end-to-end solution while touching the next billion population. We describe our work in the context of social transfers by Government of India like NREGA payments and also present the architecture of a solution which can be used by 1) Business Correspondents who go into the remote villages to disburse payments 2) consumers directly, who can through a voice channel conduct their transactions of money transfers. Our solution can be used to provide an array of services across industries like banking, finance, agriculture, health-care and education to the end user, thereby not only reducing the cost of delivery, but also making the entire innovation scalable.
On weighted U-statistics for stationary processes

A weighted U-statistic based on a random sample X1,…,Xn has the form Un=∑1≤i,j≤nwi−jK(Xi,Xj), where K is a fixed symmetric measurable function and the wi are symmetric weights. A large class of statistics can be expressed as weighted U-statistics or variations thereof. This paper establishes the asymptotic normality of Un when the sample observations come from a nonlinear time series and linear processes.
Therapeutic Embolization with Detachable Balloons

In our first 18 months’ clinical experience with embolization in the chest and abdomen using detachable balloons, successful results were obtained in 34 of 38 patients. One and 2-mm detachable silicone balloons, which can occlude vessels 4-8 mm in diameter, were employed. Prolonged balloon inflation was routinely achieved using iso-osmotic iodipamide meglumine as the filler and limiting inflation volumes to experimentally determined maximums. Improvements in introducer catheter design simplified delivery of the balloon into a variety of circulations.
Lower Limits of Discrete Universal Denoising

In the spirit of results on universal compression, we compare the performance of universal denoisers on discrete memoryless channels to that of the best performance obtained by an omniscient kth-order sliding-window denoiser, namely, one that is tuned to the transmitted noiseless sequence. We show that the additional loss incurred in the worst case by any universal denoiser on a length- n sequence grows at least like Omega(ck/radicn) , where c is a constant depending on the channel parameters and the loss function. This shows that for fixed k the additional loss incurred by the Discrete Universal Denoiser (DUDE) is no larger than a constant multiplicative factor of the best possible. Furthermore, we compare universal denoisers to denoisers that are aware of the distribution of the transmitted noiseless sequence. We show that, even for this weaker target loss, for any universal denoiser there exists some distribution for the noiseless sequence corresponding to a sequence of independent and identically distributed (i.i.d.) random variables whose optimum expected loss is lower than that incurred by the universal denoiser by Omega(1/radicn).
Calibration, Error Analysis, and Ongoing Measurement Process Monitoring for Mass Spectrometry

We consider problems of quantifying and monitoring accuracy and precision of measurement in mass spectrometry, particularly in contexts where there is unavoidable day-to-day/period-to-period changes in instrument sensitivity. First, we consider the issue of estimating instrument sensitivity based on data from a typical calibration study. Simple method-of-moments methods, likelihood-based methods, and Bayes methods based on the one-way random effects model are illustrated. Then, we consider subsequently assessing the precision of an estimate of a mole fraction of a gas of interest in an unknown. Finally, we turn to the problem of ongoing measurement process monitoring and illustrate appropriate setup of Shewhart control charts in this application.
Analysis of multiplex gene expression maps obtained by voxelation

Gene expression signatures in the mammalian brain hold the key to understanding neural development and neurological disease. Researchers have previously used voxelation in combination with microarrays for acquisition of genome-wide atlases of expression patterns in the mouse brain. On the other hand, some work has been performed on studying gene functions, without taking into account the location information of a gene's expression in a mouse brain. In this paper, we present an approach for identifying the relation between gene expression maps obtained by voxelation and gene functions. To analyze the dataset, we chose typical genes as queries and aimed at discovering similar gene groups. Gene similarity was determined by using the wavelet features extracted from the left and right hemispheres averaged gene expression maps, and by the Euclidean distance between each pair of feature vectors. We also performed a multiple clustering approach on the gene expression maps, combined with hierarchical clustering. Among each group of similar genes and clusters, the gene function similarity was measured by calculating the average gene function distances in the gene ontology structure. By applying our methodology to find similar genes to certain target genes we were able to improve our understanding of gene expression patterns and gene functions. By applying the clustering analysis method, we obtained significant clusters, which have both very similar gene expression maps and very similar gene functions respectively to their corresponding gene ontologies. The cellular component ontology resulted in prominent clusters expressed in cortex and corpus callosum. The molecular function ontology gave prominent clusters in cortex, corpus callosum and hypothalamus. The biological process ontology resulted in clusters in cortex, hypothalamus and choroid plexus. Clusters from all three ontologies combined were most prominently expressed in cortex and corpus callosum. The experimental results confirm the hypothesis that genes with similar gene expression maps might have similar gene functions. The voxelation data takes into account the location information of gene expression level in mouse brain, which is novel in related research. The proposed approach can potentially be used to predict gene functions and provide helpful suggestions to biologists.
Why You Can’T Find a Taxi in the Rain and other Labor Supply Lessons from Cab Drivers*

I replicate and extend the seminal work of Camerer et al. ("Labor Supply of New York City Cabdrivers: One Day at a Time," Quarterly Journal of Economics, 112 [1997], 407–441), who find that the wage elasticity of daily hours of work for New York City taxi drivers is negative and conclude that their labor supply behavior is consistent with reference dependence. In contrast, my analysis of the complete record of all trips taken in NYC taxi cabs from 2009 to 2013 shows that drivers tend to respond positively to unanticipated as well as anticipated increases in earnings opportunities. Additionally, using a discrete choice stopping model, the probability of a shift ending is strongly positively related to hours worked but at best weakly related to income earned. I find substantial heterogeneity across drivers in their elasticities, but the estimated elasticities are generally positive and rarely substantially negative. I find that new drivers with smaller elasticities are more likely to exit the industry, whereas drivers who remain quickly learn to be better optimizers (have positive labor supply elasticities that grow with experience). These results are consistent with the neoclassical optimizing model of labor supply and suggest that consideration of gain-loss utility and income reference dependence is not an important factor in the daily labor supply decisions of taxi drivers. JEL Codes: D01, D03, J22.
Reactions of enynes with adsorbed metal-carbenes

Abstract Adsorbed on silica-gel or on other adsorbants (MgSO4, Na2SO4, or Na2CO3), but not in homogeneous solution, pentacarbonyl(methoxyethylidene)chromium combines with simple enynes to give bicyclo[3.1.0]hexanes. The method's usefulness is illustrated by the synthesis of a variety of previously unknown structures from simple hydrocarbons, ethers, and amines.
Noncompact Symmetries in String Theory

Abstract Noncompact groups, similar to those that appeared in various supergravity theories in the 1970's, have been turning up in recent studies of string theory. First it was discovered that moduli spaces of toroidal compacification are given by noncompact groups modded out by their maximal compact subgroups and discrete duality groups. Then it was found that many other moduli spaces have analogous descriptions. Move recently, noncompact group symmetries have turned up in effective actions used to study string cosmology and other classical configurations. This paper explores these noncompact groups in the case of toroidal compactification both from the viewpoint of low-energy effective field theory, using the method of dimensional reduction, and from the viewpoint of the string theory world-sheet. The conclusion is that all these symmetries are intimately related. In particular, we find that Chern-Simons terms in the three-form field strength H μνϱ play a crucial role.
Automatic detection of UXO magnetic anomalies using extended Euler deconvolution

We have developed an algorithm for the automatic detection of prospective unexploded ordnance (UXO) anomalies in total-field or gradient magnetic data based on the concept of the structural index (SI) of a magnetic anomaly. Identifying magnetic anomalies having specific structural indices enables the direct detection of potential UXO targets. The total magnetic field produced by a dipolelike source, such as a UXO, decays with inverse distance cubed and therefore has an SI of three, whereas the gradient data have an SI of four. The developed extended Euler deconvolution method based on the Hilbert transform provides a reliable means for calculating the spatial location, depth, and SI of compact and isolated anomalies; it has enabled us to perform automatic anomaly selection for further analysis. Our method first examines the anomaly decay and selects possible UXO anomalies based on the expected SI. We refine the result further by post-Euler amplitude analysis using the relative source strength of the anomalies selected in the first stage. The amplitude analysis statistically identifies weak anomalies that are due to noise in the data. This enhances the final result and eliminates automatic picks that fall within the noise level. We have demonstrated the effectiveness of the method using synthetic and field data sets.
Magnetospheric cavity modes driven by solar wind dynamic pressure fluctuations

[1] We present results from Lyon-Fedder-Mobarry (LFM) global, three-dimensional magnetohydrodynamic (MHD) simulations of the solar wind-magnetosphere interaction. We use these simulations to investigate the role that solar wind dynamic pressure fluctuations play in the generation of magnetospheric ultra-low frequency (ULF) pulsations. The simulations presented in this study are driven with idealized solar wind input conditions. In four of the simulations, we introduce monochromatic ULF fluctuations in the upstream solar wind dynamic pressure. In the fifth simulation, we introduce a continuum of ULF frequencies in the upstream solar wind dynamic pressure fluctuations. In this numerical experiment, the idealized nature of the solar wind driving conditions allows us to study the magnetospheric response to only a fluctuating upstream dynamic pressure, while holding all other solar wind driving parameters constant. The simulation results suggest that ULF fluctuations in the solar wind dynamic pressure can drive magnetospheric ULF pulsations in the electric and magnetic fields on the dayside. Moreover, the simulation results suggest that when the driving frequency of the solar wind dynamic pressure fluctuations matches one of the natural frequencies of the magnetosphere, magnetospheric cavity modes can be energized.
Preferential Trade Agreements and Their Role in World Trade

The author investigates the effects of preferential trade agreements (PTAs) on bilateral trade flows using a comprehensive database of PTAs in force and a detailed matrix of world trade. He shows that total trade between PTA partners is a poor proxy for preferential trade (trade in tariff lines where preferences are likely to matter): while the former amounted to one-third of global trade in 2000-02, the latter was between one-sixth and one-tenth of world trade. His gravity model estimates indicate that using total rather than preferential trade to assess the impact of PTAs leads to a significant downward bias in the PTA coefficient. The author finds that product exclusions and long phase-in periods significantly limit preferential trade, and their removal could more than double trade in tariff lines above 3 percent of most-favored-nation (MFN) duties. He also shows that the effects of PTAs on trade vary by type of agreement and are increasing in the incomes of PTA partners.
Nucleophilic Acylation of o-Quinone Methides: An Umpolung Strategy for the Synthesis of α-Aryl Ketones and Benzofurans

The synthesis of α-aryl ketones is accomplished by the direct nucleophilic acylation of o-quinone methide electrophiles. In this process, two reactive intermediates, carbonyl anions and o-quinone m...
Superresolution techniques and ISAR imaging

High-resolution optimal estimation techniques are applied to the problem of radar imaging of rotating objects, sometimes referred to as ISAR (inverse synthetic array radar) imaging. Typical digital range-Doppler processing operations are described, utilizing two spectral estimation techniques. Quality ISAR images have been obtained from such processing, and particular examples, which are based on simulated data generated from point-target models of rotating objects, are shown. The first example is a so-called merry-go-round of 24 point-targets, and the MLM (maximum-likelihood method) algorithm is utilized to process a 3-D range-Doppler image estimate. The second example is a rotating boom along which are located 15 point-targets including a doublet, a triplet, and a quadruplet cluster that require superresolution techniques to resolve in the Doppler domain. It is concluded that superresolution techniques offer a viable alternative to conventional DFT (discrete Fourier transform) ISAR image processing and should permit either higher resolution images from the same data samples or equal-quality images from significantly fewer data samples. >
An oxidized oligothiophene that forms π-stacks

Abstract A dimethoxyterthiophene, substituted in the terminal α-positions with thioacetate groups, was synthesized and characterized. It was studied using cyclic voltammetry, ESR and optical spectroscopy in water solvent. A stable cation radical was formed using anodic or potassium ferrocyanide oxidation. In water the cation radical was aggregated into π-stacks, as signified by an optical conduction band in the NIR, shifts in the Vis π-π ∗ bands and an anisotropic ESR signal. This is the first example of such oligothiophene π-stacks. Evaporation of the water from an oxidized sample gave a black solid which had a four-point-probe conductivity as a pressed pellet of 10 −3 S cm −1 . Thus, oligothiophenes have been shown to provide molecular conductors and the possible importance of π-stacks in polythiophenes has been reinforced.
Aerodynamics of Bluff-Body Stabilized Confined Turbulent Premixed Flames

Detailed information on the influence of geometric and flow parameters on the structure and properties of recirculation zone in confined combusting flows is not available. In this paper, recirculation zone structure and turbulence properties of methane-air mixtures downstream of several conical flameholders were measured using LDA. These tests employed different blockage ratios (13 and 25 percent), cone angles (30, 45, 60, and 90 deg), equivalence ratios (0.56, 0.65, 0.8, and 0.9), mean annular velocities (10, 15, and 20 m/s), and approach turbulence levels (2, 17, and 22 percent). It was found that increasing the blockage ratio and cone angle affected the recirculation zone size and shape only slightly. Also, these parameters increased the shear stress and turbulent kinetic energy (TKE) moderately. Increasing the equivalence ratio or approach turbulence intensity produced a recirculation zone shape very similar to that found in the cold flow. TKE decreased due to turbulent dilatation produced by increased heat release. These observations are discussed from the viewpoint of their importance to practical design and combustion modeling.
Bounds on 4D conformal and superconformal field theories

We derive general bounds on operator dimensions, central charges, and OPE coefficients in 4D conformal and $ \mathcal{N} = 1 $ superconformal field theories. In any CFT containing a scalar primary ϕ of dimension d we show that crossing symmetry of $ \left\langle {\phi \phi \phi \phi } \right\rangle $ implies a completely general lower bound on the central charge c ≥ f c (d). Similarly, in CFTs containing a complex scalar charged under global symmetries, we bound a combination of symmetry current two-point function coefficients τ IJ and flavor charges. We extend these bounds to $ \mathcal{N} = 1 $ superconformal theories by deriving the superconformal block expansions for four-point functions of a chiral superfield Φ and its conjugate. In this case we derive bounds on the OPE coefficients of scalar operators appearing in the Φ × Φ† OPE, and show that there is an upper bound on the dimension of Φ†Φ when dim Φ is close to 1. We also present even more stringent bounds on c and τ IJ . In supersymmetric gauge theories believed to flow to superconformal fixed points one can use anomaly matching to explicitly check whether these bounds are satisfied.
Bit loading algorithms for cooperative OFDM systems

We investigate the resource allocation problem for an OFDM cooperative network with a single source-destination pair and multiple relays. Assuming knowledge of the instantaneous channel gains for all links in the entire network, we propose several bit and power allocation schemes aiming at minimizing the total transmission power under a target rate constraint. First, an optimal and efficient bit loading algorithm is proposed when the relay node uses the same subchannel to relay the information transmitted by the source node. To further improve the performance gain, subchannel permutation, in which the subchannels are reallocated at relay nodes, is considered. An optimal subchannel permutation algorithm is first proposed and then an efficient suboptimal algorithm is considered to achieve a better complexity-performance tradeoff. A distributed bit loading algorithm is also proposed for ad hoc networks. Simulation results show that significant performance gains can be achieved by the proposed bit loading algorithms, especially when subchannel permutation is employed.
Sociality and solitude

“How can I, who am thinking about the entire, centerless universe, be anything so specific as this: this measly creature existing in a tiny morsel of space and time?” This metaphysically self-deprecating question, posed by Thomas Nagel, holds an insight into the nature of personhood and the ordinary ways we value it, in others and in ourselves. I articulate that insight and apply it to the phenomena of friendship, companionship, sexuality, solitude, and love. Although love comes in many forms, I say, it always involves a sense of wonder at a finite creature thinking infinite thoughts.
Muon Colliders and Neutrino Factories

Over the past decade, there has been significant progress in developing the concepts and technologies needed to produce, capture, and accelerate O(1021) muons per year. These developments have paved the way for a new type of neutrino source (neutrino factory) and a new type of very high energy lepton-antilepton collider (muon collider). This article reviews the motivation, design, and research and development for future neutrino factories and muon colliders.
Improved fast white-light scanning profilometer

White-light Vertical Scanning Interferometry (VSI) is a well-established technique for retrieving the three-dimensional shape of small objects. It has the advantage of non-contact measurement with absolute depth resolution at nanometer level repeatability. The technique has proven to be very effective in measurements of microstructures such as MEMS devices, surface texture, roughness, etc. However, it can only measure areas as big as the field of view of the instrument, usually not more than 15 mm, or a stitching algorithm must be applied. This slows down the measurements and often can be a source of errors. In this paper we present a modification of the technique permitting measurements at higher speeds while retaining the overall accuracy and repeatability of VSI. In the presented method the object is scanned laterally in front of an instrument with a tilted coherence plane such that the data is acquired continuously eliminating the need for stitching for elongated objects. One of the advantages of the proposed system is possibility of faster scanning speed with the use of a high speed CCD arrays. In the paper we present the principle of the method along with an experimental confirmation.
The role of migration in the evolution of phenotypic switching

Stochastic switching is an example of phenotypic bet hedging, where an individual can switch between different phenotypic states in a fluctuating environment. Although the evolution of stochastic switching has been studied when the environment varies temporally, there has been little theoretical work on the evolution of phenotypic switching under both spatially and temporally fluctuating selection pressures. Here, we explore the interaction of temporal and spatial change in determining the evolutionary dynamics of phenotypic switching. We find that spatial variation in selection is important; when selection pressures are similar across space, migration can decrease the rate of switching, but when selection pressures differ spatially, increasing migration between demes can facilitate the evolution of higher rates of switching. These results may help explain the diverse array of non-genetic contributions to phenotypic variability and phenotypic inheritance observed in both wild and experimental populations.