cssi/SciSciGPT-SciSciNet huggingface dataset:
An Experimental Study of Heat Induced Surface-Tension Driven Flow

Velocity and temperature measurements are taken of heat induced surface-tension driven flows in both silicone oil and Fluorinert FC-43. Each fluid is contained in an open rectangular box and heated from above by a single strand of electrically heated nichrome wire suspended slightly above the fluid's surface. Velocity measurements are obtained for both liquids with a laser anemometer system. For silicone oil the general flow pattern is recorded using time-lapse photography. The surface temperature measurements are taken by a radiation thermometer and the bulk temperature distributions are measured by thermocouples. The velocity and temperature measurements are compared with numerical solutions obtained for the present configuration.
Does Daylight Saving Time Save Energy? Evidence from a Natural Experiment in Indiana

Abstract We take advantage of a natural experiment in the state of Indiana to estimate the effect of daylight saving time (DST) on residential electricity consumption. Our main finding is that, contrary to the policy's intent, DST increases electricity demand. The findings are consistent with simulation results that identify a trade-off between reducing demand for lighting and increasing demand for heating and cooling. We estimate a cost to Indiana households of $9 million per year in increased electricity bills. We also estimate social costs of increased pollution emissions between $1.7 to $5.5 million per year.
Is there liquid water on Europa

It is possible that tidal dissipation in an ice crust on Europa preserved a liquid water layer beneath it, provided that the three-body orbital resonance for Io, Europa, and Ganymede is ancient. The liquid water layer could be a continuing source of the observed surface frost. If Europa's water mantle were ever completely frozen, heating by tidal dissipation would not exceed that produced by radioactive elements, and the mantle would remain frozen.
Hybrid coding for Gaussian broadcast channels with Gaussian sources

This paper considers a degraded Gaussian broadcast channel over which Gaussian sources are to be communicated. When the sources are independent, this paper shows that hybrid coding achieves the optimal distortion region, the same as that of separate source and channel coding. It also shows that uncoded transmission is not optimal for this setting. For correlated sources, the paper shows that a hybrid coding strategy has a better distortion region than separate source-channel coding below a certain signal to noise ratio threshold. Thus, hybrid coding is a good choice for Gaussian broadcast channels with correlated Gaussian sources.
Protein evolution within a structural space.

Understanding of the evolutionary origins of protein structures represents a key component of the understanding of molecular evolution as a whole. Here we seek to elucidate how the features of an underlying protein structural “space” might impact protein structural evolution. We approach this question using lattice polymers as a completely characterized model of this space. We develop a measure of structural comparison of lattice structures that is analogous to the one used to understand structural similarities between real proteins. We use this measure of structural relatedness to create a graph of lattice structures and compare this graph (in which nodes are lattice structures and edges are defined using structural similarity) to the graph obtained for real protein structures. We find that the graph obtained from all compact lattice structures exhibits a distribution of structural neighbors per node consistent with a random graph. We also find that subgraphs of 3500 nodes chosen either at random or according to physical constraints also represent random graphs. We develop a divergent evolution model based on the lattice space which produces graphs that, within certain parameter regimes, recapitulate the scale-free behavior observed in similar graphs of real protein structures.
Performance portability on EARTH: a case study across several parallel architectures

Due to the increase of the diversity of parallel architectures, and the increasing development time for parallel applications, performance portability has become one of the major considerations when designing the next generation of parallel program execution models, APIs, and runtime system software. This paper analyzes both code portability and performance portability of parallel programs for fine-grained multi-threaded execution and architecture models. We concentrate on one particular event-driven fine-grained multi-threaded execution model--EARTH, and discuss several design considerations of the EARTH model and runtime system that contribute to the performance portability of parallel applications. We believe that these are important issues for future high end computing system software design. Four representative benchmarks were conducted on several different parallel architectures, including two clusters listed in the 23rd supercomputer TOP500 list. The results demonstrate that EARTH based programs can achieve robust performance portability across the selected hardware platforms without any code modification or tuning.
Historical Perspectives on the Entrepreneur

This survey establishes a chronological trace of the entrepreneur as treated in economic literature in order to give a more wholesome perspective to contemporary writings and teachings on entrepreneurship. The authors review the historical nature and role of the entrepreneur as revealed in economic literature from the 18th century to the present. This survey shows the ambiguous nature of a concept that, due to Schumpeter’s dominant influence, has come to occupy a primary role in the theory of economic development. In addition, there are other conceptions of entrepreneurship presented besides Schumpeter’s. This historical survey also illustrates the tension that often exists between “theory” and “practice.” We shall learn that it has been difficult for economic theory to assimilate a core concept that plays a vital role in social and economic change. Finally, the authors expose the many different facets of entrepreneurship as they have been perceived by some of the great economists throughout the ages.
Consensus, Institutions, and Supply Response : The Political Economy of Agricultural Reforms in Sub-Saharan Africa

During the late 1980s and the 1990s, most countries in Sub-Saharan Africa implemented agricultural policy reforms, along with national political and economic reforms. The agricultural reforms focused on opening up processing and marketing activities to increased competition and eliminating export taxes and restrictions to improve producer incentives. In eight of nine country/commodity case studies analyzed in this paper, output responded positively in the short run to the reforms. In many cases, however, the initial supply response was not sustained in the face of subsequent shocks. The studies suggest that stakeholder consensus on the distribution of sector-specific rents is a key variable affecting the sustainability of supply responses. Agricultural sector reforms lead to large changes in income distribution. The greater the acceptance of the distribution of rents following the reforms, the better sectors are able to accommodate subsequent shocks. In cases where the initial consensus on the distribution of rents is weak, shocks lead to reform reversals in some cases or an inability to design necessary support institutions in others. The diversity in outcomes across similar products and countries suggests it is possible to achieve sector and local level results that differ from national ones.
Photovoltaic Power Generation for Utilities: The Implications of Some Recent Projects and Design Studies

A discussion is given of experience, to date, in the construction and operation of six recent moderately large (?100 kW) photovoltaic power plants that are interconnected with electric utility transmission/distribution grids. Three recent design studies of utility-scale (100-200 MW) photovoltaic generating plants are also described. On the basis of the project experience and the design studies, some answers are obtained for likely utility industry questions about this novel generation technology.
Second-order properties of families of discrete-event systems

We consider discrete-event systems (DES) whose logical component is characterized by a constraint set and whose temporal mechanism involves synchronization of the clock sequence with a master clock. We are interested in determining sufficient conditions on the constraint sets of a family of such synchronous DES which ensure that the event counting process of one system dominates the convex combination of the event counting processes of a collection of systems. Our point of departure is a result due to Glasserman and Yao (1992), which established a sufficient condition based on characteristic functions. We show that the characteristic function condition is equivalent to a simpler condition on the score spaces themselves, and introduce coevality to obtain weaker sufficient conditions. We prove the near-concavity of the throughput in various parameters for min-linearly constrained DES. These results are then extended to the class of generalized min-linearly constrained DES. >
Tracer techniques in estimating nuclear materials holdup

Residual inventory of nuclear materials remaining in processing facilities (holdup) in recognized as an insidious problem for safety of plat operations and safeguarding of special nuclear materials (SNM). This paper reports on an experimental study where a well-known method of radioanalytical chemistry, namely tracer technique, was successfully used to improve nondestructive measurements of holdup of nuclear materials in a variety of plant equipment. Such controlled measurements can improve the sensitivity of measurements of residual inventories of nuclear materials in process equipment by several orders of magnitude and the good quality data obtained lend themselves to developing mathematical models of holdup of SNM during stable plant operations.
The use of reactors in biomining processes

Microbial processes applied to mining operations are gaining increasing interest in the last years. Potential and current applications include the mining of gold, copper and other heavy metals, desulfurization of coal and oil, tertiary recovery of oil and biosorption of metal ions. Currently, bacterial leaching of copper and biooxidation of refractory gold concentrates are wellestablished large-scale processes that are carried on using heaps and tank reactors. Heap operation is simple and adequate to handle large volumes of minerals, but their productivity and yields are limited because of the severe difficulties in exerting an adequate process control. On the other hand, reactors can economically handle moderate volumes of material, but they allow for a close control of the variables involved, rendering significantly better performances. This paper reviews the basis of reactor selection and design for bioleaching processes. Special attention is given to the influence of oxygen and carbon dioxide mass transfer, process stoichiometry, solids suspension and slurry homogeneity, and the use of bioreactors in gold mining. It is concluded that the future of reactors in biomining is promising and that new applications, such as the bioleaching of copper concentrates, will soon be a reality.
The new Form 8-K disclosures

The Securities and Exchange Commission (SEC) has mandated new disclosure requirements in Form 8-K, which became effective on August 23, 2004. The SEC expanded the list of items that have to be reported and accelerated the timeliness of these reports. This study examines the market reactions to 8-Ks filed under the new SEC regime and investigates whether periodic reports (10-K/Qs) became less informative under the new 8-K disclosure rules. We observe that the newly required 8-K items constitute over half of all filings and that most firms disclose the required items within the new shortened period (four business days). We find that all disclosed items (old and new) are associated with abnormal volume and return volatility around both the event and the SEC filing dates, and some items have significant return drifts after the SEC filings. Surprisingly, we find that the information content of periodic reports has not diminished by the more expansive and timely 8-K disclosures under the new guidance, possibly indicating that investors may use periodic filings to interpret the effects of material events that had been disclosed earlier.
The Making of a Global European Economist

SUMMARY This paper provides results of a survey of European graduate programs that are designing their programs to be similar to top US programs and compares those results to an earlier study done by the author of US schools. The study (1) provides a profile of European graduate economics students; (2) considers the degree to which European training at these schools differs from U.S. training, (3) offers some insights into the differences that exist among some top European programs in economics, and (4) provides a glimpse of the views that the students have of economics and of the training they are receiving. It finds that these global European programs are similar in many ways to US programs and that the students are satisfied with the programs. However, because of the different job markets in the US and Europe, it is not clear that the training is appropriate for the majority of European students. The paper concludes with a discussion of some of the concerns that should be kept in mind by other programs as they consider adapting their programs to become a ‘global’ program. These concerns include the argument that the traditional European system did a number of things right; the European academic economics institutional structure is quite different from the U.S. institutional structure; and the U.S. system has its own set of problems.
Category selectivity in the ventral visual pathway confers robustness to clutter and diverted attention

Are objects coded by a small number of neurons or cortical regions that respond preferentially to the object in question, or by more distributed patterns of responses, including neurons or regions that respond only weakly? Distributed codes can represent a larger number of alternative items than sparse codes [1-3] but produce ambiguities when multiple items are represented simultaneously (the "superposition" problem) [1, 4]. Recent studies found category information in the distributed pattern of response across the ventral visual pathway, including in regions that do not "prefer" the object in question [5-8]. However, these studies measured neural responses to isolated objects, a situation atypical of real-world vision, where multiple objects are usually present simultaneously ("clutter"). We report that information in the spatial pattern of fMRI response about standard object categories is severely disrupted by clutter and eliminated when attention is diverted. However, information about preferred categories in category-specific regions is undiminished by clutter and partly preserved under diverted attention. These findings indicate that in natural conditions, the pattern of fMRI response provides robust category information only for objects coded in selective cortical regions and highlight the vulnerability of distributed representations to clutter [1, 2] and the advantages of sparse cortical codes in mitigating clutter costs.
High-SIR Transmission Capacity of Wireless Networks With General Fading and Node Distribution

In many wireless systems, interference is the main performance-limiting factor, and is primarily dictated by the locations of concurrent transmitters. In many earlier works, the locations of the transmitters is often modeled as a Poisson point process for analytical tractability. While analytically convenient, the PPP only accurately models networks whose nodes are placed independently and use ALOHA as the channel access protocol, which preserves the independence. Correlations between transmitter locations in non-Poisson networks, which model intelligent access protocols, makes the outage analysis extremely difficult. In this paper, we take an alternative approach and focus on an asymptotic regime where the density of interferers η goes to 0. We prove for general node distributions and fading statistics that the success probability Ps ~ 1 - γηκ for η → 0, and provide values of γ and κ for a number of important special cases. We show that κ is lower bounded by 1 and upper bounded by a value that depends on the path loss exponent and the fading. This new analytical framework is then used to characterize the transmission capacity of a very general class of networks, defined as the maximum spatial density of active links given an outage constraint.
Carbocyclization of unsaturated thioesters under palladium catalysis

An intramolecular thioester–olefin cross-coupling reaction for the preparation of cyclic ketone structures from unsaturated thioesters is described. This method capitalizes on the unique reactivity of thioesters with low-valent palladium catalysts and copper(I) salts to form acyl-metal species. Trapping of such intermediates with alkene functional groups generates the corresponding exo-methylene cycloalkanone products. Unsaturated thioester substrates, which can be accessed using a suite of modern synthetic methods, can now be regarded as precursors to complex carbocyclic derivatives.
Energy-Efficient Nonstationary Spectrum Sharing

We develop a novel design framework for energy-efficient spectrum sharing among autonomous users who aim to minimize their energy consumptions subject to minimum throughput requirements. Most existing works proposed stationary spectrum sharing policies, in which users transmit at fixed power levels. Since users transmit simultaneously under stationary policies, to fulfill minimum throughput requirements, they need to transmit at high power levels to overcome interference. To improve energy efficiency, we construct nonstationary spectrum sharing policies, in which the users transmit at time-varying power levels. Specifically, we focus on TDMA (time-division multiple access) policies in which one user transmits at each time (but not in a round-robin fashion). The proposed policy can be implemented by each user running a low-complexity algorithm in a decentralized manner. It achieves high energy efficiency even when the users have erroneous and binary feedback about their interference levels. Moreover, it can adapt to dynamic entry and exit of users. The proposed policy is also deviation-proof, namely autonomous users will find it in their self-interests to follow it. Compared to existing policies, the proposed policy can achieve an energy saving of up to 90% under a large number of users.
Legal Institutions and Financial Development

A burgeoning literature finds that financial development exerts a first-order impact on long-run economic growth, which raises critical questions, such as why do some countries have well-developed growth-enhancing financial systems while others do not? The law and finance theory focuses on the role of legal institutions in explaining international differences in financial development. First, the law and finance theory holds that in countries where legal systems enforce private property rights, support private contractual arrangements, and protect the legal rights of investors, savers are more willing to finance firms and financial markets flourish. Second, the different legal traditions that emerged in Europe over previous centuries and were spread internationally through conquest, colonization, and imitation help explain cross-country differences in investor protection, the contracting environment, and financial development today. But there are countervailing theories and evidence that challenge both parts of the law and finance theory. Many argue that there is more variation within than across legal origin families. Others question the central role of legal tradition and point to politics, religious orientation, or geography as the dominating factor driving financial development. Finally, some researchers question the central role of legal institutions and argue that other factors, such as a competitive products market, social capital, and informal rules are also important for financial development. Beck and Levine describe the law and finance theory, along with skeptical and competing views, and review empirical evidence on both parts of the law and finance view.
The activation of η5-pyrrole complexes toward nucleophilic attack

Abstract Pyrrole is a five-membered aromatic heterocycle in which the nitrogen lone pair is delocalized over the π system of the ring. As a result of this π electron rich character, it reacts readily with electrophiles, but is not susceptible to nucleophilic attack. The η 5 -coordination of pyrrole or of the pyrrolyl anion to certain transition metal fragments activates the heterocycle toward nucleophilic substitution or addition reactions. In the pyrrolyl complexes (C 4 H 4 N)Re(PPh 3 ) 2 (H)(I) and (C 4 H 4 N)Ru(PEt 3 ) 2 Cl, nucleophilic substitution reactions at the 2-position of the ring follow a pathway that involves hydrogen transfer from the ring to the metal ion with displacement of a labile halide ligand from the metal center. Nucleophilic addition of hydride and methoxide anions to the neutral pentamethylpyrrole ligands in [(MeNC 4 Me 4 )M(cymene)](OTf) 2 , M=Ru and Os, has been found to occur at the α carbon atom of the heterocycle. However, reactions of other pyrrole sandwich complexes with nucleophiles may display competing reaction sites.
Extremum-seeking nonlinear controllers for a human exercise machine

In this paper, a next generation exercise machine controller is developed for a single degree of freedom (DOF) system to maximize the user's power output and ensure passivity with the user. In an effort to optimize the user's power expenditure, a desired velocity trajectory is developed that seeks the unknown user-dependent optimal velocity setpoint. Two extremum-seeking algorithms are presented (e.g., Kristic and Deng, and Tuekosky et al.) that seek the optimal velocity setpoint while ensuring the trajectory is sufficiently differentiable. To track the reference trajectory and to ensure passivity, two controllers are developed. The first controller is developed based on the assumption that the user's torque input can be measured. A second controller is designed that estimates the user's torque input. Both controllers are proven to ensure that the exercise machine remains passive with respect to the user's power output. The controllers are proven to yield semiglobal tracking through Lyapunov-based analyses. Proof-of-concept experimental results are provided that illustrate the performance of the torque estimation controller.
Zero-Energy Sag Corrector With Reduced Device Count

Voltage sags are the leading cause of unscheduled downtime in industrial plants with high levels of automation. Zero-energy sag correctors (ZESCs) that utilize energy from those phases that have sufficient remaining voltage on them promise levels of protection that are comparable with conventional energy storage based sag correctors, but in a more compact package. This paper presents a ZESC topology with reduced device count using readily available device packages that can realize similar performance as the original ZESC circuit. The proposed ZESC behaves like a ldquothin AC converter,rdquo and can be integrated with existing assets such as transformers and switchgears. This paper presents details of the operation, design, and experimental results for such a ZESC circuit.
High resolution exponential modeling of fully polarized radar returns

A method for modeling full polarization radar target is considered. The approach taken is to estimate a set of target features which describes the target as a set of attributed scattering centers. Each scattering center is characterized by its range, amplitude, and a polarization ellipse. An exponential model for the fully polarized radar return is described, and an algorithm for estimating the parameters in this model is developed. The modeling procedure is applied to compact range measurements of model aircraft. >
Ranks of twists of elliptic curves and Hilbert's tenth problem

In this paper we investigate the 2-Selmer rank in families of quadratic twists of elliptic curves over arbitrary number fields. We give sufficient conditions on an elliptic curve so that it has twists of arbitrary 2-Selmer rank, and we give lower bounds for the number of twists (with bounded conductor) that have a given 2-Selmer rank. As a consequence, under appropriate hypotheses we can find many twists with trivial Mordell-Weil group, and (assuming the Shafarevich-Tate conjecture) many others with infinite cyclic Mordell-Weil group. Using work of Poonen and Shlapentokh, it follows from our results that if the Shafarevich-Tate conjecture holds, then Hilbert’s Tenth Problem has a negative answer over the ring of integers of every number field.
The V-ATPase a2-subunit as a putative endosomal pH-sensor.

V-ATPase (vesicular H + -ATPase)-driven intravesicular acidification is crucial for vesicular trafficking. Defects in vesicular acidification and trafficking have recently been recognized as essential determinants of various human diseases. An important role of endosomal acidification in receptor–ligand dissociation and in activation of lysosomal hydrolytic enzymes is well established. However, the molecular mechanisms by which luminal pH information is transmitted to the cytosolic small GTPases that control trafficking events such as budding, coat formation and fusion are unknown. Here, we discuss our recent discovery that endosomal V-ATPase is a pH-sensor regulating the degradative pathway. According to our model, V-ATPase is responsible for: (i) the generation of a pH gradient between vesicular membranes; (ii) sensing of intravesicular pH; and (iii) transmitting this information to the cytosolic side of the membrane. We also propose the hypothetical molecular mechanism involved in function of the V-ATPase a2-subunit as a putative pH-sensor. Based on extensive experimental evidence on the crucial role of histidine residues in the function of PSPs (pH-sensing proteins) in eukaryotic cells, we hypothesize that pH-sensitive histidine residues within the intra-endosomal loops and/or C-terminal luminal tail of the a2-subunit could also be involved in the pH-sensing function of V-ATPase. However, in order to identify putative pH-sensitive histidine residues and to test this hypothesis, it is absolutely essential that we increase our understanding of the folding and transmembrane topology of the a-subunit isoforms of V-ATPase. Thus the crucial role of intra-endosomal histidine residues in pH-dependent conformational changes of the V-ATPase a2-isoform, its interaction with cytosolic small GTPases and ultimately in its acidification-dependent regulation of the endosomal/lysosomal protein degradative pathway remain to be determined.
Sonography of the Female Urethra

The purpose of this study was to explore the role of sonography for women with urethral symptoms and a suspected urethral diverticulum.Nineteen women with urethral symptoms underwent voiding cystourethrography (VCUG) and transvaginal, transperineal, and urethral sonography (using a catheter-based transducer). VCUGs and sonograms were evaluated for diverticula, defined on sonography by direct visualization of the neck connecting the periurethral sac with the urethral lumen. The diverticular neck, size, location, and shape were noted. Lesions revealed by sonography as not connected to the urethra were also noted.Of 19 women, 14 had urethral diverticula and one had two diverticula, for a total of 15 diverticula. On sonography the diverticula ranged in diameter from 2 mm to 5 cm. Both sonography and VCUG showed 13 of the 15 diverticula. In addition, sonography revealed two infected periurethral cysts, a periurethral leiomyoma, a diffuse urethritis, and scarring or deformity of one patient's urethra from a pri...
Construction and Testing of a Pixellated CZT Detector and Shield for a Hard X-ray Astronomy Balloon Flight

We report on the construction and laboratory testing of pixellated CZT detectors mounted in a flip-chip, tiled fashion and read out by an ASIC, as required for proposed hard X-ray astronomy missions. Two 10 mm X 10 mm X 5 mm detectors were fabricated, one out of standard eV Products high-pressure Bridgman CZT and one out of IMARAD horizontal Bridgman CZT. Each was fashioned with a 4 X 4 array of gold pixels on 2.5 mm pitch with a surrounding guard ring. The detectors were mounted side by side on a carrier card, such that the pixel pitch was preserved, and read out by a 32-channel VA-TA ASIC from IDE AS Corp. controlled by a PC/104 single-board computer. A passive shield/collimator surrounded by plastic scintillator encloses the detectors on five sides and provides an approximately 40 degree field of view. Thus this experiment tests key techniques required for future hard X-ray survey instruments. The experiment was taken to Ft. Sumner, NM in May 2000 in preparation for a scientific balloon flight aboard the joint Harvard-MSFC EXITE2/HERO payload. Although we did not receive a flight opportunity, and are currently scheduled to fly in September 2000, we present our calibration data in the flight configuration together with data analysis techniques and simulations of the expected flight background spectrum.
Link concordance, boundary link concordance and eta-invariants

We study eta-invariants of links and show that in many cases they form link concordance invariants, in particular that many eta-invariants vanish for slice links. This result contains and generalizes previous invariants by Smolinsky and Cha–Ko. We give a formula for the eta-invariant for boundary links. In several interesting cases this allows us to show that a given link is not slice. We show that even more eta-invariants have to vanish for boundary slice links.
Crystal growth of new strontium iron rhodium oxides: Sr4Fe0.73Rh2.27O9 and SrFe0.71Rh0.29O3

Abstract Single crystals of two new strontium iron rhodates, SrFe0.71Rh0.29O3 and Sr4Fe0.73Rh2.27O9, have been grown and structurally characterized. Single crystals of SrFe0.71Rh0.29O3 and Sr4Fe0.73Rh2.27O9 were grown from potassium carbonate melts. SrFe0.71Rh0.29O3 crystallizes in the cubic perovskite structure, space group Pm 3 m , with a=3.9027(6) A. Sr4Fe0.73Rh2.27O9 crystallizes with trigonal symmetry in the space group P321, a=9.6091(2) A and c=7.9448(2) A, and is structurally related to the 2H-hexagonal perovskites. Sr4Fe0.73Rh2.27O9 contains two independent 1-D chains of face-sharing polyhedra with a sequence of two RhO6 octahedra and one Fe/RhO6 trigonal prism and strontium cations separating the chains. The growth conditions, structures and magnetic properties of these compounds are discussed.
Mechanical heating by active galaxies.

Jets and winds are significant channels for energy loss from accreting black holes. These outflows mechanically heat their surroundings, through shocks as well as gentler forms of heating. We discuss recent efforts to understand the nature and distribution of mechanical heating by central active galactic nuclei (AGN) in clusters of galaxies, using numerical simulations and analytic models. Specifically, we will discuss whether the relatively gentle ‘effervescent heating’ mechanism can compensate for radiative losses in the central regions of clusters, and account for the excess entropy observed at larger radii. J. Binney (2005 Phil. Trans. R. Soc. A , 363 , 739−749, doi: 10.1098/rsta.2004.1520) discusses the possible role of violent, episodic heating by AGN in clusters.
2,2,6,6-Tetramethylpiperidine-Catalyzed, Ortho-selective Chlorination of Phenols by Sulfuryl Chloride

2,2,6,6-Tetramethylpiperidine (TMP)-catalyzed (1–10%) chlorinations of phenols by SO2Cl2 in aromatic solvents are more ortho selective than with primary and less hindered secondary amine catalysts. Ortho-selective chlorination is successful even with electron deficient phenols such as 2-hydroxybenzaldehyde and 2′-hydroxyacetophenone. Notably, ortho selectivity increases with the reaction temperature. On the other hand, tetraalkylammonium chloride-catalyzed chlorinations are moderately para selective.
LAW AND CORPORATE GOVERNANCE

▪ Abstract Corporate governance concerns three sets of issues: property rights, relationships between firms and financial markets, and labor relations. Our literature review shows that the system of corporate governance that emerges within a particular country reflects the outcome of political, social, and economic struggles in that country and that it does not reflect efficiency considerations focused on managing agency relations between owners and managers. Despite these facts, much research has been done in recent years attempting to analyze whether a superior matrix of institutional arrangements or a set of best practices of corporate governance exists to produce greater economic growth. Our review shows that there does not appear to be a single set of best practices, but rather that what is important are stable institutions that are legitimate and prevent extreme rent seeking on the part of governments and capitalists.
Mixed-strategy equilibria in the Nash Demand Game

In the Nash Demand Game, each of the two players announces the share he demands of an amount of money that may be split between them. If the demands can be satisfied, they are; otherwise, neither player receives any money. This game has many pure-strategy equilibria. This paper characterizes mixed-strategy equilibria. The condition critical for an equilibrium is that players’ sets of possible demands be balanced. Two sets of demands are balanced if each demand in one set can be matched with a demand in the other set such that they sum to one. For Nash’s original game, a complete characterization is given of the equilibria in which both players’ expected payoffs are strictly positive. The findings are applied to the private provision of a discrete public good.
Incorporating concept hierarchies into usage mining based recommendations

Recent studies have shown that conceptual and structural characteristics of a website can play an important role in the quality of recommendations provided by a recommendation system. Resources like Google Directory, Yahoo! Directory and web-content management systems attempt to organize content conceptually. Most recommendation models are limited in their ability to use this domain knowledge. We propose a novel technique to incorporate the conceptual characteristics of a website into a usage-based recommendation model. We use a framework based on biological sequence alignment. Similarity scores play a crucial role in such a construction and we introduce a scoring system that is generated from the website's concept hierarchy. These scores fit seamlessly with other quantities used in similarity calculation like browsing order and time spent on a page. Additionally they demonstrate a simple, extensible system for assimilating more domain knowledge. We provide experimental results to illustrate the benefits of using concept hierarchy.
Strange attractors in drift wave turbulence

There are growing experimental, numerical and theoretical evidences that the anomalous transport observed in tokamaks and stellarators is caused by slow, drift-type modes (such as trapped electron modes and ion-temperature gradient-driven modes). Although typical collision frequencies in hot, magnetized fusion plasmas can be quite low in absolute values, collisional effects are nevertheless important since they act as dissipative sinks. As it is well known, dissipative systems with many (strictly speaking more than two) degrees of freedom are often chaotic and may evolve towards a so-called attractor.
The Consumption Response to Predictable Changes in Discretionary Income: Evidence from the Repayment of Vehicle Loans

Abstract Although the life cycle/permanent income hypothesis is the primary framework for understanding household consumption and savings decisions, only a few studies have used clearly identifiable income changes to test the basic predictions of the model. The estimates produced using this empirical strategy have yet to lead to a consensus of beliefs since the results have both favored and rejected the model. This paper contributes to this literature by examining the consumption reaction to predictable increases in discretionary income following the final payment of a vehicle loan. Using data from the Consumer Expenditure Survey, the results show that a 10% increase in discretionary income due to a loan repayment leads to a 2% to 3% increase in nondurable consumption. Additional analysis suggests that these findings may be explained by the presence of borrowing constraints.
New physics from the top at the LHC

The top quark may hold the key to new physics associated with the electroweak symmetry-breaking sector, given its large mass and enhanced coupling to the Higgs sector. We systematically categorize generic interactions of a new particle that couples to the top quark and a neutral particle, which is assumed to be heavy and stable, thus serving as a candidate for cold dark matter. The experimental signatures for new physics involving top quarks and its partners at the Large Hadron Collider (LHC) may be distinctive, yet challenging to disentangle. We optimize the search strategy at the LHC for the decay of the new particle to a top quark plus missing energy and propose the study of its properties, such as its spin and couplings. We find that, at 14 TeV with an integrated luminosity of 100 fb−1, a spin-zero top partner can be observed at the 5σ level for a mass of 675 GeV. A spin-zero particle can be differentiated from spin-1/2 and spin-1 particles at the 5σ level with a luminosity of 10 fb−1.
Screening for perceptual skills dysfunction: An up-date

This paper argues that the primary-care practitioner has an obligation to screen the visual and auditory perceptual skills of his/her elementary school-aged patients. Two easy-to-administer tests are described along with guidelines for interpreting and making decisions on the basis of test outcomes.
PI degree parity in q-skew polynomial rings

Abstract For k a field of arbitrary characteristic, and R a k-algebra, we show that the PI degree of an iterated skew polynomial ring R [ x 1 ; τ 1 , δ 1 ] ⋯ [ x n ; τ n , δ n ] agrees with the PI degree of R [ x 1 ; τ 1 ] ⋯ [ x n ; τ n ] when each ( τ i , δ i ) satisfies a q i -skew relation for q i ∈ k × and extends to a higher q i -skew τ i -derivation. We confirm the quantum Gel'fand–Kirillov conjecture for various quantized coordinate rings, and calculate their PI degrees. We extend these results to completely prime factor algebras.
Dilemmas of Political Leadership in the Arab Middle East: The Case of The United Arab Republic

The use of traditional symbols by leaders of newly independent states to achieve consensus in their respective political communities is not unusual these days. The professed aspiration of these leaders to modernize their societies does not keep them from manipulating traditional symbols for the maintenance of order in a period of troubled transition. Often the student of politics in these states finds that formal changes in the institutions and functions of the state and government do not necessarily reflect or imply serious structural and conceptual changes. Nor do they necessarily affect appreciably the concept, use, or allocation of power. When members of the military establishment acceded to political power in some Middle Eastern states in the past decade, they announced their intention to “modernize” their societies. This aspiration raises a variety of questions for the student of Middle Eastern politics. What political ideology, order, and system was the new leadership proposing? The desire to “modernize” implied that their societies were still bound in a complex of traditional relationships and structures. The attitudes of the new military leaders, who claim to desire a departure from the past in national development, toward the Islamic religious-traditional background of society should be a primary factor in any analysis of the orientation of this new leadership.
Structured topological complexes: a feature-based API for non-manifold topologies

Much of recent research in representation schemes for solid modeling was focused on the extension of boundary representations to support non-manifold topologies. We introduce here a very simple, yet general formalism, which subsumes and simplifies many previous attempts at defining high-level operators for creating and interrogating such models. Our Structured Topological Complex (STC) extends our previous work on Selective Geometric Complexes (SGC) and on Constructive Non-Regularized Geometry (CNRG) and provides the foundations for a new generation of representations -both constructive and evaluated-and of APIs that are independent of the particular geometric domain and even of the particular approximation scheme for geometric primitives.
Behavioral idiosyncrasy reveals genetic control of phenotypic variability

Quantitative genetics has primarily focused on describing genetic effects on trait means and largely ignored the effect of alternative alleles on trait variability, potentially missing an important axis of genetic variation contributing to phenotypic differences among individuals. To study the genetic effects on individual-to-individual phenotypic variability (or intragenotypic variability), we used Drosophila inbred lines and measured the spontaneous locomotor behavior of flies walking individually in Y-shaped mazes, focusing on variability in locomotor handedness, an assay optimized to measure variability. We discovered that some lines had consistently high levels of intragenotypic variability among individuals, whereas lines with low variability behaved as although they tossed a coin at each left/right turn decision. We demonstrate that the degree of variability is itself heritable. Using a genome-wide association study (GWAS) for the degree of intragenotypic variability as the phenotype across lines, we identified several genes expressed in the brain that affect variability in handedness without affecting the mean. One of these genes, Ten-a, implicates a neuropil in the central complex of the fly brain as influencing the magnitude of behavioral variability, a brain region involved in sensory integration and locomotor coordination. We validated these results using genetic deficiencies, null alleles, and inducible RNAi transgenes. Our study reveals the constellation of phenotypes that can arise from a single genotype and shows that different genetic backgrounds differ dramatically in their propensity for phenotypic variabililty. Because traditional mean-focused GWASs ignore the contribution of variability to overall phenotypic variation, current methods may miss important links between genotype and phenotype.
A perspective on time: loss frequencies, time scales and lifetimes

Environmental context The need to describe the Earth’s system or any of its components with a quantity that has units of time is ubiquitous. These quantities are used as metrics of the system to describe the response to a perturbation, the cumulative effect of an action or just the budget in terms of sources and sinks. Given a complex, non-linear system, there are many different ways to derive such quantities, and careful definitions are needed to avoid mistaken approximations while providing useful parameters describing the system. Abstract Diagnostic quantities involving time include loss frequency, decay times or time scales and lifetimes. For the Earth’s system or any of its components, all of these are calculated differently and have unique diagnostic properties. Local loss frequency is often assumed to be a simple, linear relationship between a species and its loss rate, but this fails in many important cases of atmospheric chemistry where reactions couple across species. Lifetimes, traditionally defined as total burden over loss rate, are mistaken for a time scale that describes the complete temporal behaviour of the system. Three examples here highlight: local loss frequencies with non-linear chemistry (tropospheric ozone); simple atmospheric chemistry with multiple reservoirs (methyl bromide) and fixed chemistry but evolving lifetimes (methyl chloroform). These are readily generalised to other biogeochemistry and Earth system models.
L'Etat peut-il rendre compétitif les clubs de football français ?

En France, le football est devenu une question politique. S'inquietant du recul des clubs francais dans les competitions europeennes, le Gouvernement reflechit a plusieurs reformes visant a doter les clubs de ressources financieres plus importantes pour rivaliser avec les meilleurs clubs europeens. Ce papier empirique, fonde sur une base de donnees en panel, identifie les principaux determinants d'investissement des clubs de Ligue 1 et Ligue 2 et estime l'impact des principales pistes de reformes envisagees. Les resultats econometriques suggerent que si les reformes envisagees (renovation des stades, fiscalite allegee, redistribution des droits audiovisuels en faveur des meilleurs clubs) pourraient permettre de reduire l'ecart financier entre les meilleurs clubs francais et europeens, elles ne permettraient pas de le combler. Elles pourraient egalement etre jugees excessives, au regard du cout financier pour l'Etat et la remise en question du principe de solidarite entre clubs.
Type Two Cuts, Bad Cuts and Very Bad Cuts

Type two cuts, bad cuts and very bad cuts are introduced in [10] for studying the relationship between Loeb measure and U-topology of a hyperfinite time line in an w I -saturated nonstandard universe. The questions concerning the existence of those cuts are asked there. In this paper we answer, fully or partially, some of those questions by showing that: (I) type two cuts exist, (2) the R1 -isomorphism property implies that bad cuts exist, but no bad cuts are very bad. ?0. Introduction. Although the questions in [10] were discussed in a nonstandard universe, the definition of type two cuts and the proof of their existence in ? 1 can be carried out in any nonstandard models of Peano Arithmetic. We choose to work within some nonstandard universe throughout the whole paper only for coherence. The reader who is not familiar with nonstandard universe and is only interested in the result in ? 1 could consider a nonstandard universe as a nonstandard model of Peano Arithmetic in both ?0 and ?1 without any difficulties. All nonstandard universes mentioned in this paper are co -saturated. Given a nonstandard universe V, let * N denote the set of all positive integers in V and N denote the set of all standard positive integers. Following [10], a non-empty initial segment U of *N (under the natural order of *N) is called a cut if U is closed under addition, i.e., (Vx, y E U) (x + y E U) is true (U is called an additive cut in some literature). For example, N is the smallest cut and *N is the largest cut. There are several ways of constructing new cuts from given cuts shown in [10]. For example, if U is a cut and x is an element in *N. then the set xU = {y E *N: (3z E U) (y < xz)} is a cut. If the element x is in *N K U, then the set x/U -= y C*N: (Vz E U) (y < x/z)} is also a cut. Given a cut U, let M(U) = {y E *N: (Vz E U) (yz E U)}, where M suggests multiplication. Then M( U) is a cut and closed under multiplication. The cut U is called a type one cut if U xM(U) for some x E U or U = x/M(U) for some x C *N x U. U is called a type two cut if it is not type one. Received October 12, 1995; revised April 3, 1996. 1991 Mathematics Subject Classification. Primary 03H05, 03H 15, 03C50. This research was partially supported by NSF postdoctoral fellowship #DMS-9508887. ? 1997, Association for Symbolic Logic 0022-4812/97/6204-001 5/$2.20