cssi/SciSciGPT-SciSciNet huggingface dataset:
The Effect of Fading, Channel Inversion, and Threshold Scheduling on Ad Hoc Networks

This paper addresses three issues in the field of ad hoc network capacity: the impact of (i) channel fading, (ii) channel inversion power control, and (iii) threshold-based scheduling on capacity. Channel inversion and threshold scheduling may be viewed as simple ways to exploit channel state information (CSI) without requiring cooperation across transmitters. We use the transmission capacity (TC) as our metric, defined as the maximum spatial intensity of successful simultaneous transmissions subject to a constraint on the outage probability (OP). By assuming the nodes are located on the infinite plane according to a Poisson process, we are able to employ tools from stochastic geometry to obtain asymptotically tight bounds on the distribution of the signal-to-interference (SIR) level, yielding in turn tight bounds on the OP (relative to a given SIR threshold) and the TC. We demonstrate that in the absence of CSI, fading can significantly reduce the TC and somewhat surprisingly, channel inversion only makes matters worse. We develop a threshold-based transmission rule where transmitters are active only if the channel to their receiver is acceptably strong, obtain expressions for the optimal threshold, and show that this simple, fully distributed scheme can significantly reduce the effect of fading.
Variation of distribution factors with loading

Power transfer distribution factors depend on the operating point and topology of an electric power system. However, it is known empirically that, for a fixed topology, the power transfer distribution factors are relatively insensitive to the operating point. We demonstrate this result theoretically for systems of arbitrary topology with losses, but only for the special case of having reactive compensation sufficient to keep voltages constant at all busses. We also analyze a power to current distribution factor that more closely relates to thermal constraints. We provide empirical corroboration for the theoretical result.
A successful concept for measuring non-planarity of graphs: the crossing number

This paper surveys how the concept of crossing number, which used to be familiar only to a limited group of specialists, emerges as a significant graph parameter. This paper has dual purposes: first, it reviews foundational, historical, and philosophical issues of crossing numbers, second, it shows a new lower bound for crossing numbers. This new lower bound may be helpful in estimating crossing numbers.
Palladium‐Catalyzed Enantioselective Allylic Alkylations through C–H Activation

This is the first catalytic enantioselective allylic C—H alkylation, accomplished by the use of a new class of phosphoramidite ligands.
A generalized polygamma function

We study the properties of a function ψ(z, q) (the generalized polygamma function), intimately connected with the Hurwitz zeta function and defined for complex values of the variables z and q, which is entire in the variable z and reduces to the usual polygamma function ψ(m)(q) for z a non-negative integer m, and to the balanced negapolygamma function ψ(−m)(q) introduced in Ref. [5] for z a negative integer −m. *E-mail: oliver.espinosa@fis.utfsm.cl
Palladium mediated stereospecific synthesis of 3-enynyl substituted thioflavones/flavones

Abstract The stereocontrolled synthesis of enynes has been accomplished via a sequential Heck–Sonogashira reaction in a simple synthetic operation. A variety of terminal alkynes were reacted with 3-iodo(thio)flavone in the presence of a palladium catalyst and a copper salt affording a mild and one-pot method for the first synthesis of the corresponding 3-enynyl and/or alkynyl derivatives. The mechanism and scope of the reaction are discussed.
Spatial information in large-scale neural recordings.

To record from a given neuron, a recording technology must be able to separate the activity of that neuron from the activity of its neighbors. Here, we develop a Fisher information based framework to determine the conditions under which this is feasible for a given technology. This framework combines measurable point spread functions with measurable noise distributions to produce theoretical bounds on the precision with which a recording technology can localize neural activities. If there is suffi□cient information to uniquely localize neural activities, then a technology will, from an information theoretic perspective, be able to record from these neurons. We (1) describe this framework, and (2) demonstrate its application in model experiments. This method generalizes to many recording devices that resolve objects in space and should be useful in the design of next generation scalable neural recording systems.
Rearrangements accompanying fluorination of 2-amino alcohols and 1,2-diols with Deoxo-Fluor™

Abstract 2-Amino alcohols and 1,2-diols treated with Deoxo-Fluor™ in methylene chloride resulted in the formation of rearranged major products concomitantly with minor amounts of the straightforward fluorinated replacement products in good yields.
Enumerating Minimal Dicuts and Strongly Connected Subgraphs and Related Geometric Problems

We consider the problems of enumerating all minimal strongly connected subgraphs and all minimal dicuts of a given directed graph G=(V,E). We show that the first of these problems can be solved in incremental polynomial time, while the second problem is NP-hard: given a collection of minimal dicuts for G, it is NP-complete to tell whether it can be extended. The latter result implies, in particular, that for a given set of points \({\mathcal A}\subseteq{\mathbb R}^n\), it is NP-hard to generate all maximal subsets of \({\mathcal A}\) contained in a closed half-space through the origin. We also discuss the enumeration of all minimal subsets of \({\mathcal A}\) whose convex hull contains the origin as an interior point, and show that this problem includes as a special case the well-known hypergraph transversal problem.
The Sociology of Markets

AbstractThe sociology of markets has been one of the most vibrant fields in sociology in the past 25 years. There is a great deal of agreement that markets are social structures characterized by extensive social relationships between firms, workers, suppliers, customers, and governments. But, like in many sociological literatures, the theory camps that have formed often seem to speak by each other. We show that some of the disagreement between theory camps is due to differences in conceptual language, and other disagreements stem from the fact that theory camps ignore the concepts in other theory camps, thereby making their theories less complete. We end by considering deeper controversies in the literature that seem open both to new conceptualization and further empirical research.
Isometry testing for anterior cruciate ligament reconstruction revisited.

Abstract The purpose of this study was to determine the effect, if any, that varying the distal testing position (tibial level) has on isometry data produced with a common anatomic proximal testing position at the native anterior cruciate ligament (ACL) origin. During ACL reconstruction in 25 knees, in vivo isometry measurements were recorded using two different isometry testing methods, which differed in the tibial level of the distal fixation testing point. Method 1 tested distally at a point 13 cm peripheral to the native aCL insertion on a vector in line with the tibial tunnel. Method 2 tested distally at a point central in the native ACL insertion at the level of the intercondylar floor. All tibial tunnels were standardized with similar sagittal tunnel-plateau angles and similar tunnel lengths. The proximal testing point was standardized at a point that was anatomically located at or near the central ACL origin 7 mm anterior to "over the top" in all knees. Using these methods, length changes between the proximal and distal testing points were recorded in each knee with each testing method, with the knee ranged from 70° of flexion to full extension and from 70° to 140° of flexion. From these data, a total excursion from 0° to 140° of flexion was calculated. A nonanatomic distal testing point (Method 1) produced a 6 mm ± 1 mm total excursion, whereas anatomic testing points (Method 2) in the same knees produced a 1 mm ± 1 mm total excursion. From these data, the authors conclude that the tibial level of the distal isometry testing point has a significant effect on the resultant isometry measurement such that anatomic testing points are most isometric. Isometers that produce data between nonanatomic testing points should not be used to position tunnels for ACL reconstruction and should not be used to assume the elongation forces an ACL substitute will see when fixed at different points. Conversely, the clinical relevance of this study is that both anatomic graft position and anatomic graft fixation position are important and, when achieved, should result in minimal graft elongation with early postoperative range of motion, leading to a more stable long-term result.
Forced Response Analysis Using a Two-Dimensional Multistage Euler Aeroelastic Solver

A two-dimensional cascade aeroelastic solver for analyzing a multistage turbomachine has been devel- oped and is reported in this paper. The required unsteady aerodynamic forces are obtained from a Euler solver based on a e ux differencing scheme. The aerodynamic solver is coupled with a typical section structural model to calculate the e utter and forced response characteristics. The aeroelastic equations are integrated in time domain by sequentially solving the structural and aerodynamic equations at each time step. The unsteady aerodynamic forces generated by the front row, a rotor row, are used to calculate the response of the blades in the aft rows. Response of the blades because of forces generated by blade (self) vibration are also included in the analysis. EROELASTIC stability (e utter) and forced response be- cause of distortions upstream of the e ow are two of the important considerations in the safe design of turbomachines. For the last several years, NASA Lewis Research Center has been developing aeroelastic analyses for turbomachines. An overview of this research was presented in Ref. 1. The over- view indicated that many analysis methods exist for unstalled e utter and forced response calculations. A range of aerody- namic and structural models have been used to obtain the aeroelastic equations. Both time and frequency domain meth- ods have been used to solve the aeroelastic equations. How- ever, the solution methods and their application were limited to analyzing an isolated blade row. Such an analysis is valid when the rows of blades of a turbomachine are far enough apart so that aerodynamic interaction effects can be neglected. The desire to minimize engine length, however, requires that the blade rows in turbomachines be closely spaced. Reducing the axial gap between the rows makes the aerodynamic inter- action effects, namely, potential e ow interaction and viscous wake interaction, even more important. The potential e ow over a row of airfoils can cause unsteadiness in both the upstream and downstream rows, and the gradients decay with a length scale equal to the pitch or chord of the cascade. The viscous wake, on the other hand, is convected downstream, and its far- e eld rate of decay is much more gradual than that of the po- tential e ow. Its effects may be felt several chords downstream. Thus, wake interaction will be present even when adjacent rows are spaced far apart. Under most conditions, both mech- anisms are present simultaneously. Additional unsteady forces are introduced when the blades in each row are vibrating. Two approaches are followed to analyze rotor› stator inter-
Estimation of Beauty Contest Auctions

Beauty contests are auction mechanisms used to buy or sell differentiated products where the auctioneer does not specify a decision rule to pick the winning bidder. Beauty contests are widely used in procuring welfare-to-work projects, freelance services, selling online ads, real estate transactions, and hiring, dating/marriage decisions. Unlike price-only auctions, beauty contests have no closed-form bidding strategies and suffer from nonmultiplicatively separable unobserved auction heterogeneity, which makes their estimation challenging. To address these challenges, we formulate beauty contests as incomplete information games and present a two-step estimator. A key contribution of our method is its ability to account for common-knowledge auction-specific unobservables using finite unobserved types. We show that unobserved auction types and distributions of bids are nonparametrically identified and recoverable in the first step using a nonparametric Expectation-Maximization (EM)-like algorithm, and that ...
On Brylawski’s Generalized Duality

We introduce a notion of duality—due to Brylawski—that generalizes matroid duality to arbitrary rank functions. This allows us to define a generalization of the matroid Tutte polynomial. This polynomial satisfies a deletion-contraction recursion, where deletion and contraction are defined in this more general setting. We explore this notion of duality for greedoids, antimatroids and demi-matroids, proving that matroids correspond precisely to objects that are simultaneously greedoids and “dual” greedoids.
Microwave-assisted preparation of fused bicyclic heteroaryl boronates: application in one-pot Suzuki couplings.

The rapid and efficient synthesis of various disubstituted 5,6-fused heterocycles using a microwave-assisted one-pot cyclization−Suzuki coupling approach is described. This work highlights the tolerance of the boronic ester functional group to a variety of reaction conditions and the utility of functionalized boronates as penultimate intermediates in the synthesis of diverse compound libraries.
Improved preparative route toward 3-arylcyclopropenes

A convenient preparative protocol for the synthesis of various 3-arylcyclopropenes in a multigram scale is disclosed. Optimization of the reaction conditions and isolation procedures allowed for significant improvement of the chemical yields of these strained products. The described protocol was used for efficient preparation of a series of 3-methyl-3-arylcyclopropenes possessing different substituents in the aromatic ring. The effect of substitution in the aryl group on the stability of 3-arylcyclopropenes, as well as the corresponding precursors, is discussed.
A Graduate Seminar on Problems in Professional Psychology

The post-World War I1 years have seen the development of the science of psychology and the applications of psychology, an increase in the number of psychologists with wide employment in other than academic settings. Indeed, this development has been coupled with the increased professionalization of psychology into the largest single group in the mental health area. There has been related growth in programs of graduate study as well as the large scale output of doctoral level psychologists. In opening the seminar in 1991 I indicated that psychology has at least five referents: (1) an academic discipline, (2) a science, (3) a profession, (4) a business, and (5) a union. The emphasis and concern here is on the third of these. This seminar was provided first in 1951 at the University of Maryland for doctoral students (Andrews, Ayers, Cofer, Hackman, Heintz, & Ross, 1954). It has been given regularly at Howard University, not as part of the graduate program in clinical psychology, but is suggested for students in biological, personality, developmental and other specializations as well as for students in counseling and school psychology from the School of Education. While an earlier version of the seminar was presented by Ross (19771, this note describes the latest and last version. The purpose of the seminar is to familiarize the students with the profession of psychology-ics problems, issues, status, controls, achievements, and trends. The goal is to consider the appropriate information on current emphases, pressures, and developments. The seminar inuoduces students to psychology as a profession and is responsive to their interests and expectations. The initial session involves a presentation and discussion of the University, the Department, the Faculty, the graduate program, specializations, facilities, and research programs. The sources are histories of the Univers~ty, the department, the handbook for graduate students, etc. Graduate Study in Psychology is examined for its description of educational programs, specializations, and other information. This review permits a placement and understanding of the Howard University program and provides a frame for the size, scope, and variation in graduate education in psychology as well as the purposes and outcomes of such study. Students are not greatly interested in other programs or in general ouccornes. They are interested mainly in the successful and rapid completion of their studies and experiences, departure from the University, and becoming psychologists. The analysis of the profession of psychology centers about the history, structure and operations of the APA, membership, divisions, as well as regional, state and other associations of psychologists, including the recent formation of the American Psychological SocieQ and the American Association of Applied and Preventive Psychology. The major sources used are the APA Monitor, the American Psychologist, and the Directory of the American Psychological Association, together with sources regarding issues in training and education, master's level and doctoral level psychol
Regularity, depth and arithmetic rank of bipartite edge ideals

We study minimal free resolutions of edge ideals of bipartite graphs. We associate a directed graph to a bipartite graph whose edge ideal is unmixed, and give expressions for the regularity and the depth of the edge ideal in terms of invariants of the directed graph. For some classes of unmixed edge ideals, we show that the arithmetic rank of the ideal equals projective dimension of its quotient.
A direct conversion of (α-hydroxyalkyl)silanes to carboxylic acids

Abstract (α-Hydroxyalkyl)trialkylsilanes and acylsilanes are readily oxidized to the corresponding carboxylic acid using ozone.
Competition Policy in Network Industries: An Introduction

We discuss issues of the application of antitrust law and regulatory rules to network industries. In assessing the application of antitrust in network industries, we analyze a number of relevant features of network industries and the way in which antitrust law and regulatory rules can affect them. These relevant features include (among others) network effects, market structure, market share and profits inequality, choice of technical standards, relationship between the number of active firms and social benefits, existence of market power, leveraging of market power in complementary markets, and innovation races. We find that there are often significant differences on the effects of application of antitrust law in network and non-network industries.
An empirical investigation of labor income processes

Abstract In this paper, I reassess the evidence on labor income risk. There are two leading views on the nature of the income process in the current literature. The first view, which I call the “Restricted Income Profiles” (RIP) process, holds that individuals are subject to large and very persistent shocks, while facing similar life-cycle income profiles. The alternative view, which I call the “Heterogeneous Income Profiles” (HIP) process, holds that individuals are subject to income shocks with modest persistence, while facing individual-specific income profiles. I first show that ignoring profile heterogeneity, when in fact it is present, introduces an upward bias into the estimates of persistence. Second, I estimate a parsimonious parameterization of the HIP process that is suitable for calibrating economic models. The estimated persistence is about 0.8 in the HIP process compared to about 0.99 in the RIP process. Moreover, the heterogeneity in income profiles is estimated to be substantial, explaining between 56 to 75 percent of income inequality at age 55. I also find that profile heterogeneity is substantially larger among higher educated individuals. Third, I discuss the source of identification—in other words, the aspects of labor income data that allow one to distinguish between the HIP and RIP processes. Finally, I show that the main evidence against profile heterogeneity in the existing literature—that the autocorrelations of income changes are small and negative—is also replicated by the HIP process, suggesting that this evidence may have been misinterpreted.
Measurement Effects and the Variance of Returns After Stock Splits and Stock Dividends

This article examines the relation between two factors affecting stock returns, the bid-ask spread and price discreteness, and the increase in return variance after ex-dates of stock splits and stock dividends. Controlling for these effects, the variance of daily returns still increases significantly. The variance of weekly returns also increases significantly, and the variance of returns for a control sample of nonsplitting firms shows no significant increase. Variance ratio tests show that bid-ask errors are small for these stocks and therefore cannot explain the large increase in variance. Spreads and price discreteness do not explain increased variance after stock distributions. Article published by Oxford University Press on behalf of the Society for Financial Studies in its journal, The Review of Financial Studies.
Constructing two-writer atomic registers

A two-writer, n-reader atomic memory register is constructed from two one-writer, (n+1)-reader atomic memory registers. There are no restrictions on the size of the constructed register. The simulation requires only a single extra bit per real register and can survive the failure of any set of readers and writers. A complete proof of correctness is given. Several obvious ways are suggested to try to extend this algorithm to more than two writers, none of which work. As an example, it is shown how a natural extension of the two-writer protocol fails. >
The Impacts of the Canadian Wheat Board Ruling on the North American Malt Barley Markets

The 2011 Marketing Freedom for Grain Farmers Act deregulated Canadian grain markets and removed the Canadian Wheat Board (CWB) as the sole buyer and seller of Canadian grain. We develop a rational expectations contract decision model that serves as the basis for an empirically informed simulation analysis of malt barley contracting opportunities between Canadian farmers and U.S. maltsters in the deregulated environment. Comparative statics and simulation results indicate that some new opportunities for contracting are possible, but the likelihood of favorable conditions for U.S. maltsters to contract with Canadian rather than U.S. farmers is low—between 9% and 35% over a range of possible selection rates. The effects on contracting of the termination of the Canadian grain transportation revenue cap policy and of the relaxation of criteria for the release of new spring wheat varieties are also investigated. While changes to grain transportation policies are not likely to significantly affect favorable conditions for contracting, reducing constraints on Canadian farmers’ access to higher yielding wheat varieties could increase the returns from growing spring wheat but decrease the likelihood of contracting for malt barley with U.S. maltsters by an average of 5.3 percentage points. L'adoption de la Loi sur le libre choix des producteurs de grains en matiere de commercialisation en 2011 a dereglemente les marches canadiens des grains et a deloge la Commission canadienne du ble (CCB) en tant que guichet unique pour la commercialisation des grains canadiens. Nous avons elabore un modele de decisions de passation de marche fonde sur des anticipations rationnelles comme modele de base pour l'analyse par simulation des occasions de passation de marche pour l'orge brassicole entre les cerealiculteurs canadiens et les malteries etatsuniennes dans le contexte de la dereglementation. Selon les resultats de la statique comparative et de l'analyse par simulation, de nouvelles occasions de passation de marche sont possibles, mais la probabilite que les malteries etatsuniennes jouissent de conditions favorables pour conclure des marches avec des cerealiculteurs canadiens plutot qu'avec des cerealiculteurs etatsuniens est faible et varie de 9 a 35 % pour des taux de selection probables. Nous avons egalement examine les repercussions de l'abolition de la politique de plafond de revenu du transport du grain de l’Ouest sur la passation de marche ainsi que les repercussions de l'assouplissement des criteres quant a l'acces a de nouvelles varietes de ble de printemps. Alors que les modifications apportees a la politique de transport du grain ne devraient pas influencer de facon significative les conditions favorables a la passation de marche, la reduction des contraintes d'acces des cerealiculteurs canadiens a des varietes de ble a rendement eleve pourrait accroitre les revenus tires de la culture du ble de printemps mais egalement diminuer la possibilite de conclure des marches pour l'orge brassicole avec des malteries etatsuniennes d'environ 5,3 points de pourcentage.
Chemical Synthesis of GPIs and GPI-Anchored Glycopeptides

This microreview summarizes some recent progress in the study of glycosylphosphatidylinositols (GPI), focusing on the strategies established for the synthesis of optically pure myo-inositol derivatives and complex GPIs and GPI conjugates. Although in the past decade many GPIs have been achieved by linear, convergent and solid-phase synthesis, the GPIs with 2-O-acylated inositol residues and the GPI conjugates of peptides and glycopeptides have not been accomplished until recently. The successful coupling of peptides and glycopeptides to GPIs brings new promises to this area, but the scope of the relevant designs, in particular their application to more complex structures such as GPI-anchored glycoproteins, remains untested. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
LONG-PERIOD VARIABILITY IN o CETI

We carried out a new and sensitive search for long-period variability in the prototype of the Mira class of long-period pulsating variables, o Ceti (Mira A), the closest and brightest Mira variable. We conducted this search using an unbroken light curve from 1902 to the present, assembled from the visual data archives of five major variable star observing organizations from around the world. We applied several time-series analysis techniques to search for two specific kinds of variability: long secondary periods (LSPs) longer than the dominant pulsation period of ~333 days, and long-term period variation in the dominant pulsation period itself. The data quality is sufficient to detect coherent periodic variations with photometric amplitudes of 0.05 mag or less. We do not find evidence for coherent LSPs in o Ceti to a limit of 0.1 mag, where the amplitude limit is set by intrinsic, stochastic, low-frequency variability of approximately 0.1 mag. We marginally detect a slight modulation of the pulsation period similar in timescale to that observed in the Miras with meandering periods, but with a much lower period amplitude of ?2 days. However, we do find clear evidence of a low-frequency power-law component in the Fourier spectrum of o Ceti's long-term light curve. The amplitude of this stochastic variability is approximately 0.1 mag at a period of 1000 days, and it exhibits a turnover for periods longer than this. This spectrum is similar to the red noise spectra observed in red supergiants.
An optimal strategy for a conflict resolution problem

Abstract Relevant to the design of multiple access protocols is the problem of finding the largest of N i.i.d. numbers X1,…,XN uniformly distributed over [0,1] using the minimum number of questions of the following type. We pick a set A(1) ⊂ [0, 1] and ask which Xi ϵ A(1). Depending on the response, we pick another subset A(2) and ask which Xi ϵ A(2), and so on, until we identify the largest Xi. It is shown that the optimum sequence of questions must be of the type A(k) = (a(k), 1]; the best sequence {a(k)} can then be determined by dynamic programming following the work of Arrow, Pesotchinsky and Sobel.
The post-war U.S. phillips curve: a revisionist econometric history

In 1958, A.W. Phillips discovered a strong negative correlation between inflation and unemployment in United Kingdom data. Continuing controversy surrounds the long-run trade-off suggested by a curve he drew through these observations. We conduct a wide-ranging investigation of the post-war U.S. Phillips correlations and Phillips curve. Many economists view the Phillips correlations as chimerical, given the rise in both inflation and unemployment during the 197Os, and the Phillips curve as plagued by subtle identification difficulties raised by Lucas and Sargent. Yet, a strikingly stable negative correlation exists over the business cycle, and recent theory indicates the Lucas-Sargent critique may not be empirically relevant. When we estimate the long-run trade-off as Gordon and Solow did, we find it is roughly one-for-one. This traditional Keynesian identification also makes business cycles entirely due to demand shocks. However, the Gordon-Solow model is not the only one that fits the data well. Alternative identifications lead to much more modest effects of demand on business cycles and essentially negligible long-run trade-offs. *We have received many constructive comments on this paper: we particularly thank Charles Evans, Robert J. Gordon, Bennett McCallum, and Charles Plosser. Support was provided by the National Science Foundation via grant NSF-91-22463.
Eicosanoids and the esophagus

Eicosanoids are products of arachidonic acid metabolism. Among the products produced are the prostaglandins and leukotrienes, products which are known to play important roles in health and disease of many gastrointestinal tissues. Here, we review current knowledge about eicosanoids in the esophagus, including production in healthy and diseased tissues and potential physiologic and pathophysiologic effects in two important esophageal mucosal disorders, reflux esophagitis and esophageal cancer.
IMAGING THE COOL HYPERGIANT NML CYGNI'S DUSTY CIRCUMSTELLAR ENVELOPE WITH ADAPTIVE OPTICS

We present subarcsecond angular resolution, high-Strehl ratio mid-IR adaptive optics images of the powerful OH/IR source and cool hypergiant NML Cyg at 8.8, 9.8, and 11.7 ?m. These images reveal once more the complexity in the dusty envelope surrounding this star. We spatially resolve the physical structures (radius ~ 014, ~240 AU adopting a distance of 1.74 kpc) responsible for NML Cyg's deep 10 ?m silicate dust absorption feature. We also detect an asymmetric excess, at separations of ~03-05 (~520-870 AU), northwest from the star. The colors of this excess are consistent with thermal emission of hot, optically thin dust. This excess is oriented in the direction of the Cyg OB2 stellar association, and is likely due to the disruption of NML Cyg's dusty wind with the near-UV radiation flux from the massive hot stars within Cyg OB2. This interaction was predicted in our previous paper to explain the geometry of an inverted photodissociation region observed at optical wavelengths.
Convection and the seeding of the North Atlantic bloom

Abstract Observations of vertical velocities in deep wintertime mixed layers using neutrally buoyant floats show that the convectively driven vertical velocities, roughly 1000 m per day, greatly exceed the sinking velocities of phytoplankton, 10 m or less per day. These velocities mix plankton effectively and uniformly across the convective layer and are therefore capable of returning those that have sunk to depth back into the euphotic zone. This mechanism cycles cells through the surface layer during the winter and provides a seed population for the spring bloom. A simple model of this mechanism applied to immortal phytoplankton in the subpolar Labrador Sea predicts that the seed population in early spring will be a few percent of the fall concentration if the plankton sink more slowly than the mean rate at which the surface well-mixed layer grows over the winter. Plankton that sink faster than this will mostly sink into the abyss with only a minute fraction remaining by spring. The shallower mixed layers of mid-latitudes are predicted to be much less effective at maintaining a seed population over the winter, limiting the ability of rapidly sinking cells to survive the winter.
Decline in extinction rates and scale invariance in the fossil record

We show that the decline in the extinction rate during the Phanerozoic can be accurately described by a logarithmic fit to the cumulative total extinction. This implies that extinction intensity is falling off approximately as the reciprocal of time. We demonstrate that this observation alone is sufficient to explain the existence of the proposed power-law forms in the distribution of the sizes of extinction events and in the power spectrum of Phanerozoic extinction, results that previously have been explained by appealing to self-organized critical theories of evolutionary dynamics.
Motion Planning and Tracking for Tip Displacement and Deflection Angle for Flexible Beams

Explicit motion-planning reference solutions are presented for flexible beams with Kelvin-Voigt (KV) damping. The goal is to generate periodic reference signals for the displacement and deflection angle at the free-end of the beam using only actuation at the base. The explicit deflection angle reference solution is found as a result of writing the shear beam model in a strict-feedback form. Special "partial differential equation (PDE) backstepping" transformations relate the strict-feedback model to a "target system," governed by an exponentially stable wave equation with KV damping, whose displacement reference solution is relatively easy to find. The explicit beam displacement reference solution is found using the target system solution and an inverse backstepping transformation. The explicit reference solutions for the wave equation and shear beam with KV damping are novel results. State-feedback tracking boundary controllers are found by extending previous PDE backstepping stabilization results. Application of the shear beam results to the more complicated Timoshenko beam is discussed.
Regioselective Nucleophilic Aromatic Substitution of Benzo[c][2,7]naphthyridines

Over the past 25 years a number of biologically active natural products containing a benzo[c][2,7]naphthyridine subunit 1 have been reported. 1 – 3 Invariably, these natural products are C-4 and C-...
Novel Synthesis of Bifunctional Acid-Esters

A novel method was developed for the synthesis of acid-esters via monodemethylation of a dimethyl ester by 1,1-dimethylhydrazine and subsequent conversion of the resulting trimethylhydrazonium ester to the desired acid-ester. The method is facile and seems to have a wide range of applicability.
Temporal difference learning and TD-Gammon

Ever since the days of Shannon's proposal for a chess-playing algorithm [12] and Samuel's checkers-learning program [10] the domain of complex board games such as Go, chess, checkers, Othello, and backgammon has been widely regarded as an ideal testing ground for exploring a variety of concepts and approaches in artificial intelligence and machine learning. Such board games offer the challenge of tremendous complexity and sophistication required to play at expert level. At the same time, the problem inputs and performance measures are clear-cut and well defined, and the game environment is readily automated in that it is easy to simulate the board, the rules of legal play, and the rules regarding when the game is over and determining the outcome.
Highly convergent synthesis of peluroside A.

A stated objective for many efforts in total synthesis is to provide access to structures that exhibit interesting biological activity. Although this goal is unquestionably worthy of pursuit, the impact that organic synthesis can have on the supply of natural products or their analogues for biological evaluation and, ultimately, therapeutic treatment is still limited by the structural complexity and size of the targets. Convergent strategies, in which two or more subunits of the target are prepared independently and coupled at a late stage in the sequence, have been developed to facilitate large-molecule synthesis. Although convergent approaches generally do not reduce the overall step count for a synthesis, they can greatly reduce the linear step count and improve throughput. Moreover, these modular approaches to molecular construction enable the preparation of analogues from structurally diverse subunits. There have been several spectacular examples of the preparation of natural products in substantial quantities through convergent approaches in the past decade.[1] Evans et al. recently reported[2] a highly convergent approach to peloruside A (1) that has the capacity to provide useful amounts of this intriguing natural product and to supply analogues for biological evaluation. Peloruside A was isolated from sponges of the Mycale genus in New Zealand by Northcote and co-workers.[3] Its connectivity and relative configuration were established by extensive NMR spectroscopic studies. Potent cytotoxicity was observed when P388 cells were exposed to 1, and subsequent studies demonstrated that this activity arises from apoptosis induction through microtubule stabilization.[4] Although conflicting reports have emerged regarding the location of the binding site for peluroside A on microtubules,[5] it is clearly distinct from the paclitaxel binding site.[6] The presence of dual binding sites improves therapeutic potential by enabling paclitaxel and peluroside A to act synergistically.[7] The environmental sensitivity for peluroside A production from sponges,[8] however, suggests that synthesis will be the most reliable source for future biological studies.
Identification of Intergranular Cu2O in Polycrystalline YBa2Cu3O7‐x Superconductors

The presence of intergranular Cu2O has been identified in polycrystalline YBa2Cu3O7-x superconducting samples (Tc∼90 K) which are prepared by dry-powder processing techniques. Transmission electron microscopy was employed to determine the crystal structure of the phase while energy-dispersive analysis provided the composition. The intergranular Cu2O, as indicated by XRD and shown by optical microscopy, is concentrated around pores and extends back along grain boundaries adjacent to these pores. Analysis performed on samples sintered in a furnace atmosphere at 950°C, with and without a post-oxygen anneal at 450°C, gave similar results.
A tutorial on dual decomposition and lagrangian relaxation for inference in natural language processing

Dual decomposition, and more generally Lagrangian relaxation, is a classical method for combinatorial optimization; it has recently been applied to several inference problems in natural language processing (NLP). This tutorial gives an overview of the technique. We describe example algorithms, describe formal guarantees for the method, and describe practical issues in implementing the algorithms. While our examples are predominantly drawn from the NLP literature, the material should be of general relevance to inference problems in machine learning. A central theme of this tutorial is that Lagrangian relaxation is naturally applied in conjunction with a broad class of combinatorial algorithms, allowing inference in models that go significantly beyond previous work on Lagrangian relaxation for inference in graphical models.
Sustainable nuclear energy : some reasons for optimism

This paper traces various aspects of nuclear electrical power from about 1970 when it burst on the world scene, starting in the USA and spreading rapidly to the rest of the world. Taking the US situation as typical, and perhaps dominant, I show that the cost of nuclear electricity was cheap in 1973, and the developments since then mostly related to public perception, that made it more expensive. I then describe changes since 1995 that lead me to a cautiously optimistic view that public opinion is changing again and that the cost of nuclear energy will drop as public opinion becomes more favourable.
Impact-induced compositional variations on Mercury

Abstract Remote sensing data suggest Mercury's surface has compositional variations spatially associated with crater and basin ejecta, the so-called “Low-Reflectance Material” (LRM), which has been suggested to be enriched in a subsurface native darkening agent that is excavated and redeposited onto the surface. This unit may record the evidence of impact-induced mixing of Mercury's outer layers during its early history. Here, we develop a fully three-dimensional Monte Carlo model of impact cratering, excavation, and ejecta blanket deposition on a global scale for Mercury. New dynamical simulations of the early evolution of the asteroid belt hint at the presence of additional asteroids in a region interior to the present-day belt, known as the “E-belt”. We use Monte Carlo methods to show that the predicted bombardment from this population matches the observed spatial crater densities on Mercury. Impacts large enough to pierce through the crust create surface ejecta deposits rich in mantle material. Later impacts onto enriched ejecta deposits redistribute mantle material away from the basins. For the suggested average mercurian crustal thickness of 50 km, the surface has, on average, ∼0.4% mantle material by volume; the most enriched areas have ∼30% mantle by volume. The regional coverage of impact-induced compositional changes is strongly dependent on the thickness to the subsurface source. Because observations indicate LRM covers ∼15% of Mercury's surface, our model suggests the darkening agent is ∼30 km deep. Considering the current estimated average mercurian crustal thickness of 50 km, this implies the darkening agent is likely located within a chemically distinct lower crust.
Conley Conjecture for Negative Monotone Symplectic Manifolds

We prove the Conley conjecture for negative monotone, closed symplectic manifolds, i.e., the existence of infinitely many periodic orbits for Hamiltonian diffeomorphisms of such manifolds.
Sympathetic Nerve Fibers in Human Cervical and Thoracic Vagus Nerves

Background Vagus nerve stimulation (VNS) therapy has been used for chronic heart failure and is believed to improve imbalance of autonomic control by increasing parasympathetic activity. Although it is known that there is neural communication between the VN and the cervical sympathetic trunk, there are few data regarding the quantity and/or distribution of the sympathetic components within the vagus nerve (VN). Objective To examine the sympathetic components within the human VN and correlate them with the presence of cardiac and neurologic diseases. Methods We performed immunohistochemistry on 31 human cervical and thoracic VNs (total 104 VNs) from autopsies and reviewed the patients' records. We correlated the quantity of sympathetic nerve fibers within the VNs with cardiovascular and neurologic disease states. Results All 104 VNs contain tyrosine hydroxylase (TH)–positive (sympathetic) nerve fibers; the mean TH-positive areas were 5.47% in the right cervical VN, 3.97% in the left cervical VN, 5.11% in the right thoracic VN, and 4.20% in the left thoracic VN. The distribution of TH-positive nerve fibers varied from case to case: central, peripheral, or scattered throughout nerve bundles. No statistically significant differences in nerve morphology were seen between diseases in which VNS is considered effective (depression and chronic heart failure) and other cardiovascular diseases or neurodegenerative disease. Conclusion Human VNs contain sympathetic nerve fibers. The sympathetic component within the VN could play a role in physiologic effects reported with VNS. The recognition of sympathetic nerve fibers in the VNs may lead to better understanding of the therapeutic mechanisms of VNS.
Molecular Profiling and Classification of Sporadic Renal Cell Carcinoma by Quantitative Methylation Analysis

Purpose: Preoperative histologic classification of solid renal masses remains limited with current technology. We determine the utility of molecular profiling based on quantitative methylation analysis for characterization of sporadic renal cell carcinoma. Experimental Design: Primary renal cell carcinomas representing three different histologic subtypes were obtained from a total of 38 patients who underwent radical nephrectomy for suspected malignant disease. Genomic DNA was isolated from tumors and was subjected to sodium bisulfite modification. The normalized index of methylation (NIM) for each sample was determined by quantitative real-time methylation-specific PCR at 17 different gene promoters. Hierarchical cluster analysis was performed by using an unsupervised neural network with binary tree topology. Results: The majority of gene promoters that were analyzed in this study demonstrated very low levels of methylation (NIM RASSF1A gene promoter, however, was methylated in 30 of 38 (79%) cases. The frequency of RASSF1A methylation in papillary, clear-cell, and oncocytoma subtypes was 100, 90, and 25%, respectively. The highest levels of RASSF1A methylation were observed in the papillary (mean NIM = 78.9) and clear-cell (mean NIM = 13.4) subtypes. The vast majority of oncocytomas were completely unmethylated, and none demonstrated >1% methylation (mean NIM = 0.11). Hierarchical cluster analysis based on quantitative methylation levels resulted in stratification of sporadic renal cell carcinomas into their discrete histologic subtypes. Conclusions: Classification of sporadic renal cell carcinomas into histologic subtypes can be accomplished via multigene quantitative methylation profiling. Validation of this approach and selection of appropriate methylation markers may ultimately lead to use of this technology in the preoperative assessment of suspicious renal masses.
The Corpus of Contemporary American English as the first reliable monitor corpus of English

The Corpus of Contemporary American English is the first large, genre-balanced corpus of any language, which has been designed and constructed from the ground up as a 'monitor corpus', and which can be used to accurately track and study recent changes in the language. The 400 million words corpus is evenly divided between spoken, fiction, popular magazines, newspapers, and academic journals. Most importantly, the genre balance stays almost exactly the same from year to year, which allows it to accurately model changes in the 'real world'. After discussing the corpus design, we provide a number of concrete examples of how the corpus can be used to look at recent changes in English, including morph- ology (new suffixes -friendly and -gate), syntax (including prescriptive rules, quotative like, so not ADJ, the get passive, resultatives, and verb complementa- tion), semantics (such as changes in meaning with web, green, or gay), and lexis-- including word and phrase frequency by year, and using the corpus architecture to produce lists of all words that have had large shifts in frequency between specific historical periods.
The Theoretical Structure of Producer Willingness to Pay Estimates

This article analyzes the theoretical underpinnings of producer willingness to pay (WTP) for new inputs. In addition to conceptualizing the producer WTP function, we derive its comparative statics and show how these properties can be used to estimate quantities demanded or supplied and price elasticities. We also discuss implications of the comparative statics.
An engineering model for moisture degradation of polymer/metal interfacial fracture toughness

Based on interfacial fracture mechanics and the hydrophobicity of the interface, en engineering model was developed in this paper. Using this model, one can predicted the degradation of interfacial fracture toughness of a polymer/metal interface once the moisture concentration near the interface is known.