cssi/SciSciGPT-SciSciNet huggingface dataset:
Debt and Development

Abstract This paper examines incentive and valuation effects of debt financing on land investment. When land is debt financed, the landowner holds both a development option on the land and a default option on the debt. Because development typically devalues the default option, investment may be delayed past the point at which efficient investment would otherwise proceed. The incentive to underinvest is shown to be more pronounced as debt level increases, i.e., as the debt becomes riskier. This agency problem provides an explanation as to why land is generally difficult to debt finance and may also explain why debt levels are relatively low for “land-intensive” real estate firms. Novel comparative statics show that debt value may increase for a given increase in asset volatility as well as for a given increase in interest rate. Renegotiation and restrictive contract provisions are considered as mechanisms to promote efficient investment policy in the presence of debt financing.
Lewis base activation of Lewis acids. Catalytic enantioselective addition of silyl enol ethers of achiral methyl ketones to aldehydes.

A highly enantioselective addition of silyl enol ethers derived from simple methyl ketones is described. The catalyst system of silicon tetrachloride activated by a chiral bisphosphoramide (R,R)-7 effectively promotes the addition of a variety of unsubstituted silyl enol ethers to aromatic, olefinic, and heteroaromatic aldehydes in excellent yield.
U.S. and Canadian Industrial Relations: Convergent or Divergent?

Two models, the divergence and the convergence models, address comparisons of Canadian and American industrial relations. Most specialists support the divergence hypothesis. It asserts that the two countries' systems have produced major transnational differences in industrial relations outputs. The convergence model reassessed the assumptions, data, and conclusions of the divergent model and concluded that the two countries' systems produced very similar, although not identical, industrial relations outputs.
An Inverse Problem for the Heat Equation

Abstract Let u t = u xx − q ( x ) u , 0 ≤ x ≤ 1, t > 0, u (0, t ) = 0, u (1, t ) = a ( t ), u ( x , 0) = 0, where a ( t ) is a given function vanishing for t > T , a ( t ) ≢ 0, ∫ T 0 a ( t ) dt u x (0, t ) := b 0 ( t ) for all t > 0. Does this information determine q ( x ) uniquely? Do the measurements of the flux u x (1, t ) := b ( t ) give more information about q ( x ) than b 0 ( t ) does? These questions are answered in this note.
Financial constraints and output targets in Russian agricultural production

Since the breakup of the Soviet Union, Russian agricultural production has experienced a significant decline. The rise in input prices relative to output prices and the lack of legal mechanisms to provide land as a collateral for loans suggest the existence of expenditure constraints. We test for expenditure constraints and prevalence of output-targeting as sources of inefficiency in addition to actual inefficiencies in 73 Russian farm regions (oblasts). Only six oblasts are overall efficient and the rest experienced profit losses from all three sources of inefficiency of up to 35.8 per cent. We find that 54 oblasts are subject to expenditure constraints, while output-targeting is still practised by 14 oblasts. Our results suggest that one-seventh of the overall inefficiency, and thus profit losses, is due to both financial constraints and output-targeting. Copyright © 2000 John Wiley & Sons, Ltd.
A Homogeneous, Recyclable Polymer Support for Rh(I)-Catalyzed C-C Bond Formation

A robust and practical polymer-supported, homogeneous, recyclable biphephos rhodium(I) catalyst has been developed for C–C bond formation reactions. Control of polymer molecular weight allowed tuning of the polymer solubility such that the polymer-supported catalyst is soluble in nonpolar solvents and insoluble in polar solvents. Using the supported rhodium catalysts, addition of aryl and vinylboronic acids to the electrophiles such as enones, aldehydes, N-sulfonyl aldimines, and alkynes occurs smoothly to provide products in high yields. Additions of terminal alkynes to enones and industrially relevant hydroformylation reactions have also been successfully carried out. Studies show that the leaching of Rh from the polymer support is low and catalyst recycle can be achieved by simple precipitation and filtration.
Spintessence ! New models for dark matter and dark energy

Abstract We investigate a class of models for dark matter and/or negative-pressure, dynamical dark energy consisting of “spintessence”, a complex scalar field φ spinning in a U (1)-symmetric potential V ( φ )= V (| φ |). As the Universe expands, the field spirals slowly toward the origin. The internal angular momentum plays an important role in the cosmic evolution and fluctuation dynamics. We outline the constraints on a cosmic spintessence field, describing the properties of the potential necessary to sustain a viable dark energy model, making connections with quintessence and self-interacting and fuzzy cold dark matter. Possible implications for the coincidence problem, baryogenesis, and cosmological birefringence, and generalizations of spintessence to models with higher global symmetry and models in which the symmetry is not exact are also discussed.
SLE and the free field: partition functions and couplings

Schramm-Loewner Evolutions ($\SLE$) are random curves in planar simply connected domains; the massless (Euclidean) free field in such a domain is a random distribution. Both have conformal invariance properties in law. In the present article, some relations between the two objects are studied. We establish identities of partition functions between different versions of $\SLE$ and the free field with appropriate boundary conditions; this involves $\zeta$-regularization and the Polyakov-Alvarez conformal anomaly formula. We proceed with a construction of couplings of $\SLE$ with the free field, showing that, in a precise sense, chordal $\SLE$ is the solution of a stochastic "differential" equation driven by the free field. Existence, uniqueness in law, and pathwise uniqueness for these SDEs are proved for general $\kappa>0$.
Development of Early Measures of Comprehension: Innovation in Individual Growth and Development Indicators.

Early comprehension is an important, but not well-understood, contribution to early literacy and language development. Specifically, research regarding the nature of skills representative of early comprehension, including how they contribute to later reading success, is needed to support best practices to adequately prepare students. This article describes the process involved in the creation and refinement of the newly developed comprehension Individual Growth and Development Indicators (IGDIs 2.0). Two theoretical models of early comprehension are discussed to highlight the inherent complexity of this domain. Results of three studies are presented: Study 1 outlines the initial piloting process, Study 2 represents a larger-scale investigation, and Study 3 describes further field testing and reveals the final IGDI 2.0 comprehension candidate: Which One Doesn’t Belong (WODB). Results indicated WODB out-performed the other candidate measures across psychometric and pragmatic criteria. The utility of the WOD...
Induced Oscillations of a Finite Plate

Limit cycle oscillations are complex vibrations of airframe surfaces for which the cause-and-effect relationships are poorly understood. This fundamental investigation of oscillations of a  nite two-dimensional  exible plate considers unforced vibrations, as well as situations where motion is induced by a convected vortex, a pressure wave, or an unsteady boundary-layer separation on the moving plate. It is found that very complex vibration patterns can occur and, with increasing nonlinearity, essentially chaotic motion can develop. When the plate is forced at frequencies close to the natural frequencies of the linear problem, a nonlinear resonance phenomenon occurs leading to a complex limit cycle behavior.
Capture-ejector satellites

A satellite in the form of a large rotating rim which can be used to boost spacecraft from low-Earth orbit to higher orbits is described. The rim rotates in the plane of its orbit such that the lower portion of the rim is traveling at suborbital velocity, while the upper portion is travelling at greater than orbital velocity. Ascending spacecraft or payloads arrive at the lowest portion of the rim at suborbital velocities, where the payloads are released on a trajectory for higher orbits; descending payloads employ the reverse procedure. Electric thrusters placed on the rim maintain rim rotational speed and altitude. From the standpoint of currently known materials, the capture-ejector concept may be useful for relatively small velocity increments.
Mass transfer in close, rapidly accreting protobinaries: An origin for massive twins?

Rapidly accreting massive protostars undergo a phase of deuterium shell burning during pre-main-sequence evolution that causes them to swell to tenths of an AU in radius. During this phase, those with close binary companions will overflow their Roche lobes and begin transferring mass. Since massive stars frequently have companions at distances well under 1 AU, this process may affect the early evolution of a substantial fraction of massive stars. We use a simple protostellar evolution model to determine the range in accretion rates, mass ratios, and orbital separations for which mass transfer will occur, and we compute approximately the stability and final outcome of the transfer process. We discuss how mass transfer affects the demographics of massive binaries and show that it provides a natural explanation for the heretofore unexplained population of massive "twins," high-mass binaries with mass ratios very close to unity.
Raney Ni-Sn Catalyst for H2 Production from Biomass-Derived Hydrocarbons

Hydrogen (H2) was produced by aqueous-phase reforming of biomass-derived oxygenated hydrocarbons at temperatures near 500 kelvin over a tin-promoted Raney-nickel catalyst. The performance of this non-precious metal catalyst compares favorably with that of platinum-based catalysts for production of hydrogen from ethylene glycol, glycerol, and sorbitol. The addition of tin to nickel decreases the rate of methane formation from C-O bond cleavage while maintaining the high rates of C-C bond cleavage required for hydrogen formation.
On the Location of the Roots of the Derivative of a Polynomial

general parasitism to a highly specific parasitism, in the latter cases the parasite having become so perfectly modified to fit itself to the one species of host that it must mean an advanced stage of evolution. In considering the importation of parasite species we must aim to have both kinds if they exist-the specifically constituted parasites and the general parasites. From the ranks of the latter we will have great help in the destruction of large numbers of the particular insect against which it was imported, but it will have the additional advantage of accommodating itself to other injurious species, and hence on the whole will probably be a more desirable addition to the American parasite fauna. Although not parasites, mention should be made of two species of groundbeetles broughlit over from Europe in the course of the gipsy moth work. Calosoma sycophanta has been found to attack a number of injurious native caterpillars; and Carabus auratus, while probably primarily a feeder upon slugs, as it is in its native home, also feeds upon cutworms and probably other soft-bodied insects ordinarily found in or near the ground.
Spitzer Observations of Nearby M Dwarfs

We present Spitzer IRAC and MIPS observations for a sample of eight M dwarfs: six dMe, one dM, and one sdMe star. All of our targets are found to have SEDs that are fitted within the error bars by a purely photospheric spectrum out to 24 μm. We find no evidence for IR excess. None of our targets are detected in the MIPS 70 and 160 μm bands. The estimated ages for all are >10 Myr, suggesting that enough disk dissipation has occurred within the inner several AU of the star. For four of these, Mullan et al. had reported IRAS detections at 12 μm, although the reported fluxes were below the 5 σ IRAS detection limit (~0.2 Jy). Mullan et al. also pointed out that V-K colors in dMe stars are larger than those in dM stars, possibly because of the presence of a chromosphere. Here we suggest that metallicity effects provide a better explanation of the V-K data. For reasons of observational selection, our targets are not the most active flare stars known, but being dMe stars indicates the presence of a chromosphere. Scaling from Houdebine's model of the AU Mic chromosphere, we have computed the free-free IR excesses for a range of densities. Our Spitzer 24 μm data show that the chromospheres in two of our targets are less dense than in AU Mic by a factor of 10 or more. This is consistent with the fact that our sample includes the less active flare stars. Our models also indicate that the chromospheric contribution to the observed AU Mic emission at submillimeter wavelengths is only about 2%.
The Massively Parallel Processor

Future sensor systems will utilize massively parallel computing systems for rapid analysis of two-dimensional data. The Goddard Space Flight Center has an ongoing program to develop these systems. A single-instruction multiple data computer known as the Massively Parallel Processor (MPP) is being fabricated for NASA by the Goodyear Aerospace Corporation. This processor contains 16,384 processing elements arranged in a 128 x 128 array. The MPP will be capable of adding more than 6 billion 8-bit numbers per second. Multiplication of eight-bit numbers can occur at a rate of 2 billion per second. Delivery of the MPP to Goddard Space Flight Center is scheduled for 1983.
Velocity analysis by iterative profile migration

In conventional seismic processing, velocity analysis is performed by using the normal moveout (NMO) equation which is based on the assumption of flat, horizontal reflectors. Imaging by migration (either before or after stack) is done normally in a subsequent step using these velocities. In this paper, velocity analysis and imaging are combined in one step, and migration itself is used as a velocity indicator. Because, unlike NMO, migration can be formulated for any velocity function, migration‐based velocity analysis methods are capable of handling arbitrary structures, i.e., those with lateral velocity variations. In the proposed scheme, each shot gather (profile) is migrated with an initial depth‐velocity model. Profile migration is implemented in the (x, ω) domain, but the actual implementation of profile migration is not critical, as long as it is not done in a spatial‐wavenumber domain, which would preclude handling of lateral velocity variations. After migration with an initial velocity model, the ...
High Profit Strategies in Mature Capital Goods Industries: A Contingency Approach

High profit and low profit strategic “gestalts” in two different types of mature capital goods industries are examined. Multiple avenues to high profits are found within both types, but they differ...
Superconducting and Magnetic Behavior in La2-xNaxCuO4.

New phases of the type La/sub 2-x/A/sub x//sup 1 +/CuO/sub 4-y/ have been prepared where A/sup 1 +/ is sodium or potassium. The sodium phases are superconducting for x values from 0.2 to 0.5 at temperatures up to about 40 K. In addition, there are unusual magnetic properties below about 10 K that may be indicative of spin glass behavior. Phases of the type La/sub 2-x/K/sub x/CuO/sub 4-y/ could only be prepared with x values up to about 0.1, and these phases are not superconducting above 4.2 K. 10 references, 2 figures, 2 tables.
On the Measurement of Benefits in an Urban Context: Some General Equilibrium Issues

Abstract The validity of using local market data to measure the benefits associated with policies adopted in an urban area is investigated. It is shown that the rest of the world is affected by taxing decisions undertaken in a single urban area, so that local data cannot perfectly measure the welfare effects of a policy change. Specifically, the fact that the willingness to pay for a tax increase is positive in the rest of the world suggests that cost-benefit analyses which do not account for the rest of the world may be biased.
Motion by weighted mean curvature is affine invariant

Suppose curves are moving by curvature in a plane, but one embeds the plane in R3 and looks at the plane from an angle. Then circles shrinking to a round point would appear to be ellipses shrinking to an “elliptical point,” and the surface energy would appear to be anisotropic as would the mobility. The result of this paper is that if one uses the apparent surface energy and the apparent mobility, then the motion by weighted curvature with mobility in the apparent plane is the same as motion by curvature in the original plane but then viewed from the angle. This result applies not only to the isotropic case but to arbitrary surface energy functions and mobilities in the plane, to surfaces in 3-space, and (in the case that the surface energy function is twice differentiable) to the case of motion viewed through distorted lenses (i.e., diffeomorphisms) as well. This result is to be contrasted with an earlier result [4], which states that for area-preserving affine transformations of the plane where the energy and mobility are not also transformed, motion by curvature to the power 1/3 (rather than 1) is invariant.
Matrix models, Argyres-Douglas singularities and double scaling limits

We construct an = 1 theory with gauge group U(nN) and degree n+1 tree level superpotential whose matrix model spectral curve develops an Argyres-Douglas singularity. The calculation of the tension of domain walls in the U(nN) theory shows that the standard large-N expansion breaks down at the Argyres-Douglas points, with tension that scales as a fractional power of N. Nevertheless, it is possible to define appropriate double scaling limits which are conjectured to yield the tension of 2-branes in the resulting = 1 four dimensional non-critical string theories as proposed by Ferrari.
New Algorithms and Lower Bounds for Monotonicity Testing

We consider the problem of testing whether an unknown Boolean function f : { -- 1, 1}n a#x21C6; { -- 1, 1} is monotone versus aepsi;-far from every monotone function. The two main results of this paper are a new lower bound and a new algorithm for this well-studied problem. Lower bound: We prove an a#x03A9;(n1/5) lower bound on the query complexity of any non-adaptive two-sided error algorithm for testing whether an unknown Boolean function f is monotone versus constant-far from monotone. This gives an exponential improvement on the previous lower bound of a#x03A9;(log n) due to Fischer et al.[1]. We show that the same lower bound holds for monotonicity testing of Boolean-valued functions over hypergrid domains {1,,m}n for all m age; 2. Upper bound: We present an O(n5/6) poly(1/aepsi;)-query algorithm that tests whether an unknown Boolean function f is monotone versus aepsi;-far from monotone. Our algorithm, which is non-adaptive and makes one-sided error, is a modified version of the algorithm of Chakrabarty and Seshadhri[2], which makes O(n7/8) poly(1/aepsi;) queries.
Information Market-Based Decision Fusion

Improved classification performance has practical real-world benefits ranging from improved effectiveness in detecting diseases to increased efficiency in identifying firms that are committing financial fraud. Multiclassifier combination (MCC) aims to improve classification performance by combining the decisions of multiple individual classifiers. In this paper, we present information market-based fusion (IMF), a novel multiclassifier combiner method for decision fusion that is based on information markets. In IMF, the individual classifiers are implemented as participants in an information market where they place bets on different object classes. The reciprocals of the market odds that minimize the difference between the total betting amount and the potential payouts for different classes represent the MCC probability estimates of each class being the true object class. By using a market-based approach, IMF can adjust to changes in base-classifier performance without requiring offline training data or a static ensemble composition. Experimental results show that when the true classes of objects are only revealed for objects classified as positive, for low positive ratios, IMF outperforms three benchmarks combiner methods, majority, average, and weighted average; for high positive ratios, IMF outperforms majority and performs on par with average and weighted average. When the true classes of all objects are revealed, IMF outperforms weighted average and majority and marginally outperforms average.
More on Harsanyi's utilitarian cardinal welfare theorem

If individuals and society both obey the expected utility hypothesis and social alternatives are uncertain, then the social utility must be a linear combination of the individual utilities, provided the society is indifferent when all its members are. This result was first proven by Harsanyi [4] who made implicit assumptions in the proof not actually needed for the result (see [5]). This note presents a straightforward proof of Harsanyi's theorem based on a separating hyperplane argument.
Global Goals as a Policy Tool: Intended and Unintended Consequences

AbstractGlobal development goals have become increasingly used by the UN and the international community to promote priority objectives. The Millennium Development Goals (MDGs) are the most prominent example of such goals but many others have been set since the 1960s. Despite their prominence and proliferation, little has been written about the concept of global goals as a policy tool, their effectiveness, limitations and broader consequences. This paper explores global development goals as a policy tool, and the mechanisms that have two types of effects: governance effects and knowledge effects. These effects lead to both intended and unintended consequences in influencing international development strategies and action. The paper analyses the MDGs as an example to argue that global goals activate the power of numbers to create incentives for national governments and others to mobilize for important objectives. But the powers of simplification, reification and abstraction lead to broader unintended conse...
A Labor Law for the Digital Era

Key words laborlaw.employmentlaw.digitaleraThere is a serious problem with the labor and employment law system in the United Statestoday. Unions have declined to the point where they represent less than 8% of the privatesector workforce, employee wages have stagnated for more than three decades, employersare cutting back on workers’ health insurance and pensions, and there is a dramatic growthin the numbers of the working poor. At the same time, there has been a rising chorus ofcomplaints from labor scholars that the labor law has become “ossified” (Estlund 2002),that the law is failing to offer meaningful worker protection (Summers 1988; Gottesman1993), that the courts and Labor Board have abandoned the “core values of labor law”(Dannin and Bonior 2006), and that Congress has defunded the labor protective agenciessuch as the National Labor Relations Board (NLRB), the Occupational Safety and HealthAdministration (OSHA) and the Hour and Wage Division that administers the Fair LaborStandards Act (FLSA) (Dannin 2004; Brudney et al. 1999; McGarity and Shapiro 1996).Indeed, some have contended that during the past two decades, there has been a passiverepeal of the employment statutes (Hiatt and Becker 2005; Brudney 1996; Dannin andBonior 2006; Stone 1992).There is a reason that the field of labor and employment law has declined. Work itselfhas not declined in importance—it remains a central part of individual identity and aprominent aspect of social life, but the labor and employment laws do not address theconcerns or vulnerabilities of the majority of the workforce today. Instead, the regulatoryframework governing the workplace is becoming irrelevant.
Nonparallel Instability of Supersonic and Hypersonic Boundary Layers

Multiple scaling technique is used to examine the nonparallel instability of supersonic and hypersonic boundary‐layer flows to three‐dimensional (first mode) and two‐dimensional (second mode) disturbances. The method is applied to the flat plate boundary layer for a range of Mach numbers from 0 to 10. Growth rates of disturbances are calculated based on three different criteria: following the maximum of the mass‐flow disturbance, using an integral of the disturbance kinetic energy, and using an integral of the square of the mass‐flow amplitude. By following the maximum of the mass‐flow disturbance, the calculated nonparallel growth rates are in good quantitative agreement with the experimental results of Kendall at Mach number 4.5.
Terrestrial concentrating photovoltaic power system studies

Abstract Studies aimed at defining the role of sunlight concentration in reducing the cost of electrical energy generated by terrestrial photovoltaic systems are described. These studies use computer modelling to (a) compare silicon cells and gallium arsenide cells in concentrating systems, (b) investigate the operation of photovoltaic systems in low insolation locations and (c) evaluate the effect of wind dependent thermal conductances on performance of passively cooled systems. Optimum fixed energy costs occur at higher aperature to cell area ratios for GaAs systems compared to silicon systems due to the better high temperature performance and increased costs of GaAs. Results based on currently available data show that concentrating systems should not be ruled out relative to fixed flat unconcentrated arrays even for low solar irradiation locations such as Cleveland. The wind dependent thermal conductance studies show that for precise modeling the effect of wind speed should be considered in locations having large wind speed deviations from the yearly mean. However, with the present uncertainties in cost inputs, the use of average values is quite appropriate.
Direct simulation of electron transfer using ring polymer molecular dynamics: Comparison with semiclassical instanton theory and exact quantum methods

The use of ring polymer molecular dynamics (RPMD) for the direct simulation of electron transfer (ET) reaction dynamics is analyzed in the context of Marcus theory, semiclassical instanton theory, and exact quantum dynamics approaches. For both fully atomistic and system-bath representations of condensed-phase ET, we demonstrate that RPMD accurately predicts both ET reaction rates and mechanisms throughout the normal and activationless regimes of the thermodynamic driving force. Analysis of the ensemble of reactive RPMD trajectories reveals the solvent reorganization mechanism for ET that is anticipated in the Marcus rate theory, and the accuracy of the RPMD rate calculation is understood in terms of its exact description of statistical fluctuations and its formal connection to semiclassical instanton theory for deep-tunneling processes. In the inverted regime of the thermodynamic driving force, neither RPMD nor a related formulation of semiclassical instanton theory capture the characteristic turnover in the reaction rate; comparison with exact quantum dynamics simulations reveals that these methods provide inadequate quantization of the real-time electronic-state dynamics in the inverted regime.
‘Universal’ FitzGerald contractions

The model of a universe with a preferred frame, which nevertheless shares the main properties with traditional special and general relativity theories, is considered. We adopt Mach’s interpretation of inertia and show that the energy balance equation, which includes the Machian energy of gravitational interactions with the universe, can imitate standard relativistic formulas.
Absence of Ground States for a Class of Translation Invariant Models of Non-relativistic QED

We consider a class of translation invariant models of non-relativistic QED with net charge. Under certain natural assumptions we prove that ground states do not exist in the Fock space.
The Economic Incentives and Consequences of Land Write‐Ups

Firms in Taiwan are allowed to write up their assets when certain conditions are met. Tax benefits from higher depreciation expenses are granted to encourage corporate investment and capital maintenance. Land write-ups, unlike write-ups of depreciable assets, do not generate tax benefits. This paper investigates the economic incentives for firms in Taiwan to write up their land, and the security price reactions to land write-ups. An analysis of annual financial data for the manufacturing firms listed in the Taiwan Exchange between 1982 and 1992 shows that firms write up their land by a larger amount when raising capital. Firms with relatively higher debt-asset ratios write up their land by a larger amount. Furthermore, the capital raised was invested in working capital or operational assets, but not in securities of other firms. The results suggest that land write-ups may reduce firms' difficulties in raising external capital, and may enhance corporate investments. The result from capital market analysis offers weak evidence that land write-ups are positively correlated with the market adjusted rate of returns of a firm's stock.
The Cost Savings of Expanding Medicaid Eligibility to Include Currently Uninsured Homeless Adults with Substance Use Disorders

Following the June 2012 Supreme Court ruling that states are no longer mandated to expand their Medicaid programs in 2014 as part of the Affordable Care Act, many states plan to opt out of the expansion, citing affordability as their primary concern. In response to this controversy, the present study evaluated the cost savings of expanding Medicaid coverage to include currently ineligible homeless adults with substance use disorders, a subset of the population that incurs some of the greatest societal costs and is disproportionately impacted by uninsurance. Using a time horizon of 7 years, separate analyses were conducted for state and federal governments, and then a final analysis evaluated the combined costs for the other two models. Results of the study demonstrate that, although the expansion will be associated with a net cost when combining state and federal expenses and savings, states will experience tremendous savings if they choose to participate.
Daily deals: prediction, social diffusion, and reputational ramifications

Daily deal sites have become the latest Internet sensation, providing discounted offers to customers for restaurants, ticketed events, services, and other items. We begin by undertaking a study of the economics of daily deals on the web, based on a dataset we compiled by monitoring Groupon and LivingSocial sales in 20 large cities over several months. We use this dataset to characterize deal purchases; glean insights about operational strategies of these firms; and evaluate customers' sensitivity to factors such as price, deal scheduling, and limited inventory. We then marry our daily deals dataset with additional datasets we compiled from Facebook and Yelp users to study the interplay between social networks and daily deal sites. First, by studying user activity on Facebook while a deal is running, we provide evidence that daily deal sites benefit from significant word-of-mouth effects during sales events, consistent with results predicted by cascade models. Second, we consider the effects of daily deals on the longer-term reputation of merchants, based on their Yelp reviews before and after they run a daily deal. Our analysis shows that while the number of reviews increases significantly due to daily deals, average rating scores from reviewers who mention daily deals are 10% lower than scores of their peers on average.
Image Processing System To Analyze Droplet Distributions In Sprays

The General Motors Research Laboratories has developed an image processing system that automatically analyzes the size distributions in fuel spray video images. Images are generated by using pulsed laser light to freeze droplet motion in the spray sample volume under study. This coherent illumina-tion source produces images that contain droplet diffraction patterns representing the droplet's degree of focus. Thousands of images are recorded per sample volume to get an ensemble average of the distribution at that spray location. After image acquisition the recorded video frames are replayed and analyzed under computer control. The analysis is performed by extracting feature data describing droplet diffraction patterns in the images. This allows the system to select droplets from image anomalies and measure only those droplets con-sidered in focus. The system was designed to analyze sprays from a variety of environments. Currently these are an ambient spray chamber, a high pressure, high temperature spray facility, and a running engine. Unique features of the system are the totally automated analysis and droplet feature measurement from the gray scale image. Also, it can distinguish nonspherical anomalies from droplets, which allows sizing of droplets near the spray nozzle. This paper describes the feature extraction and image restoration algorithms used in the system. Preliminary performance data are also given for two experiments. One experiment gives a comparison between manual and automatic measurements of a synthesized distribution. The second experiment compares measurements of a real spray distribution using current methods and using the automatic system.
Deployment of an unreliable robotic sensor network for spatial estimation

Abstract This paper studies an optimal deployment problem for a network of robotic sensors moving in the real line. Given a spatial process of interest, each individual sensor sends a packet that contains a measurement of the process to a data fusion center. We assume that, due to communication limitations or hardware unreliability, only a fraction of the packets arrive at the center. Using convex analysis, nonsmooth analysis, and combinatorics, we show that, for various fractional rates of packet arrival, the optimal deployment configuration has the following features: agents group into clusters, clusters deploy optimally as if at least one packet from each cluster was guaranteed to reach the center, and there is an optimal cluster size for each fractional arrival rate.
Harmonic symmetries of imperfect competition on circular city

Taking location as given, we study imperfect competition on a circular city. In Bertrand oligopoly, we identify price harmonics as a function of firm unit costs and locations. The sum of oligopoly profits is larger when costs and/or locations are more dispersed in the ‘dihedral majorization’ sense. This also tends to be the case in which prices are more variable. We study how phase shifts between cost parameters and inter-firm distance parameters change production and oligopoly profits. An exact characterization of production patterns is developed in terms of the eigenvalues for what we call the price harmonics matrix. The same techniques are applied to Cournot oligopoly with spatial externalities on circular city. Solutions are compared with first-best. Production patterns can differ markedly when cost spillovers are negative.
Finite Bubbles with Short Sale Constraints and Asymmetric Information

Abstract We present a finite period general equilibrium model of an exchange economy with asymmetric information. We say that a rational expectations equilibrium exhibits a strong bubble if the price is higher than the dividend with probability one. We show that necessary conditions for a strong bubble to occur are that (1) each agent must have private information in the period and state in which the bubble occurs, (2) each agent must be short sale constrained at some period in the future with positive probability, and (3) agents′ trades are not common knowledge. We present examples of bubbles when the necessary conditions are satisfied. Journal of Economic Literature Classification Numbers: C72, D52, D82, D84, G12, G14.
Payment systems in the healthcare industry: An experimental study of physician incentives

Abstract Policy makers and the healthcare industry have proposed changes to physician payment structures as a way to improve the quality of health care and reduce costs. Several of these proposals require healthcare providers to employ a value-based purchasing program (also known as pay-for-performance [P4P]). However, the way in which existing payment structures impact physician behavior is unclear and therefore, predicting how well P4P will perform is difficult. To understand the impact physician payment structures have on physician behavior, I approximate the physician–patient relationship in a real-effort laboratory experiment. I study several prominent physician payment structures including fee-for-service, capitation, salary, and P4P. I find that physicians are intrinsically motivated to provide high quality care and relying exclusively on extrinsic incentives to motivate physicians is detrimental to the quality of care and costly for the healthcare industry.
Asymmetric Synthesis of Cyclopropyl Carbocyclic Nucleosides

Abstract A number of nucleosides have been synthesized as potential antiviral and antitumor agents.1 More recently, various dideoxynucleosides have been synthesized and found to be potent anti-HIV agents.2 As a part of our drug discovery program for the treatment of HIV and HBV, we have initiated to synthesize cyclopropyl carbocyclic nucleosides as potential antiviral agents. Several papers regarding the synthesis of cyclopropyl carbocyclic nucleosides have appeared in the literature.3–5 However, they are all reported as racemic mixtures. In this abstract, we wish to report the asymmetric synthesis of cylopropyl carbocyclic nucleosides from optically active common intermediates, 6 and 11.
Thallium selenide infrared detector.

The application of semiconducting thallium selenide for ir detection is described. A responsivity of 106 V/W and NEP of the order of 10−15 W/√Hz with a response time of 3 msec can be obtained by operating the detector at 1.5 K.
Cellular heterogeneity and live cell arrays

In the past decade, the tendency to move from a global, one-size-fits-all treatment philosophy to personalized medicine is based, in part, on the nuanced differences and sub-classifications of disease states. Our knowledge of these varied states stems from not only the ability to diagnose, classify, and perform experiments on cell populations as a whole, but also from new technologies that allow interrogation of cell populations at the individual cell level. Such departures from conventional thinking are driven by the recognition that clonal cell populations have numerous activities that manifest as significant levels of non-genetic heterogeneity. Clonal populations by definition originate from a single genetic origin so are regarded as having a high level of homogeneity as compared to genetically distinct cell populations. However, analysis at the single cell level has revealed a different phenomenon; cells and organisms require an inherent level of non-genetic heterogeneity to function properly, and in some cases, to survive. The growing understanding of this occurrence has lead to the development of methods to monitor, analyze, and better characterize the heterogeneity in cell populations. Following the trend of DNA- and protein microarrays, platforms capable of simultaneously monitoring each cell in a population have been developed. These cellular microarray platforms and other related formats allow for continuous monitoring of single live cells and simultaneously generate individual cell and average population data that are more descriptive and information-rich than traditional bulk methods. These technological advances have helped develop a better understanding of the intricacies associated with biological processes and afforded greater insight into complex biological systems. The associated instruments, techniques, and reagents now allow for highly multiplexed analyses, which enable multiple cellular activities, processes, or pathways to be monitored simultaneously. This critical review will discuss the paradigm shift associated with cellular heterogeneity, speak to the key developments that have lead to our better understanding of systems biology, and detail the future directions of the discipline (281 references).
Renormalization group evolution of neutrino masses and mixing in seesaw models: A review

We consider different extensions of the Standard Model which can give rise to the small active neutrino masses through seesaw mechanisms, and their mixing. These tiny neutrino masses are generated at some high energy scale by the heavy seesaw fields which then get sequentially decoupled to give an effective dimension-5 operator at the low energy. The renormalization group evolution of the masses and the mixing parameters of the three active neutrinos in the high energy as well as the low energy effective theory is reviewed in this paper.
Dark Matter in Clusters of Galaxies

An appropriate subtitle for this talk might be “Newton meets Einstein.” For many decades, the prime tool for studying the amount and distribution of matter in galaxy clusters was decidedly Newtonian, involving at first the measurements of the dynamics of the galaxies themselves and, for the past 15 years or so, the imputed dynamics of the hot, X-ray emitting intra-cluster gas. Einstein enters more recently with the introduction of gravitational lensing as a tool for studying cluster mass distributions. Rapid progress is being made in each of these areas, and there are now attempts to bring them together to give a consistent and more accurate picture of clusters.
Preventing and Treating Homesickness

Homesickness is a normative pathology that ranges from benign to severe. It is defined as the distress or impairment caused by an actual or anticipated separation from home and attachment objects. Symptoms of homesickness, including preoccupying thoughts of home, can be predicted, prevented, and treated. This article summarizes the latest clinical research and practice surrounding homesickness in children and adolescents. Equipped with this knowledge, health care providers can train and consult with summer camp directors and staff to properly prepare and treat new and returning campers.
Probing feedback in protogalaxies : multiphase gas in a DLA at z ≈ 2.4

WeinvestigatethephysicalprocessesoccurringinthemultiphasegasofadampedLy" absorber (DLA). We base our analysis on a high-quality Keck High-Resolution Echelle Spectrometer (HIRES) spectrum of the QSO J1211+0422 in which a DLA is detected at z ! 2.377. There is little contamination of the high-ion (O VI ,N V ,C IV, Si IV) absorption, allowing us to explore the properties of the highly ionized gas and its connection to other gas phases. The metallicity ([Z/H] =" 1.41 ± 0.08), H I column density [logN(H I) = 20.80±0.10], full-width velocity (#v neut ! 70 kms " 1 ) and relative abundances ([Si/Fe]=+0.23±0.05 and [N/Si]=" 0.88± 0.07) of this DLA are not unusual. However, we derive the lowest C II # cooling rate in a DLA, lc < 10 " 27.8 ergs " 1 per H atom (3$ ). Using this stringent limit, we show that the neutral gas (confined at |v| < +39kms " 1 ) must be warm and the star formation rate is <7.1 $ 10 " 3 M% yr " 1 kpc " 2 . Surprisingly, the gas shows strong, complex absorption profiles from highlyionizedgaswhosekinematicsappearconnectedtoeachotherandthelowions.Thetotal amount of highly and weakly ionized gas is very large with Ntot(H II)/Ntot(H I) ! 1.5. At |v| ! +39kms " 1 , the gas is fully and highly ionized [H + /H & 1,N(C IV) ' N(C II),N(Si IV) ' N(Si II)]. Based on ionization models, O VI and N V are generally difficult to produce by hard photons, while Si IV and C IV can be photoionized to a large extent. There is, however, no evidence of O VI-bearing gas at T & 10 6 K associated with this DLA. In contrast, there is some evidence for narrow O VI ,N V and C IV components (unexplained by photoionization), implyingtoolowtemperatures(T <10 5 K)forsimplecollisionalionizationmodelstoproduce their observed column densities. Stellar feedback is a possible source for producing the high ions, but we cannot rule out accretion of non-pristine material on to the protogalaxy.
S-wave velocity structure, mantle xenoliths and the upper mantle beneath the Kaapvaal craton

SUMMARY Inversion of two-station Rayleigh-wave fundamental-mode phase velocities across the undisturbed region of the southern Kaapvaal craton south of the Bushveld Province produces velocity-depth models quantitatively similar to those estimated from low-T mantle xenoliths brought to the surface in Cretaceous-age kimberlite pipes that erupted in the same region. The cratonic xenolith suite was previously analysed thermobarometrically and chemically to obtain the equilibrium P-T conditions from which the seismic velocities and density of the cratonic mantle to about 180 km depth were calculated. As the xenoliths represent a snapshot of the mantle at the time of their eruption, comparison with recently recorded seismic data provides an opportunity to compare and contrast the independently gained results. We form a composite reference velocity model using xenolith values for the depth range 50–180 km with an interpolated join to PREM for the depth range 220–500 km, and a regionally determined crustal model for the upper 35 km. This composite served as the starting model for a linearized least-squares inversion (LLSI) using fundamental-mode Rayleigh-wave phase velocities in the period range 18–171 s measured for five events along 16 two-station paths within the southern Kaapvaal craton. Based on xenolith data, we constrain the vP/vS ratio in the inversion to vary from about 1.72 in the uppermost mantle to 1.78 at 180 km depth. The velocity structures determined by surface-wave inversion are consistent with those derived from the xenolith data, suggesting that the velocity structure (i.e. thermal structure) of the mantle to a depth of 180 km beneath the Kaapvaal craton today is similar to that at ∼70–90 Ma, the time of kimberlite eruption. Results from both surface-wave inversion and xenolith calculations indicate that S-wave velocities decrease slightly with depth beneath the craton, from a value around 4.7 km s−1 in the uppermost mantle to about 4.60–4.65 km s−1 at a depth of 180–200 km. We performed tests based on a wide range of starting models, and found no models with a minimum vS in the mantle less than about 4.55 km s−1 down to a depth of 250 km within the resolution possible from an inversion based on fundamental-mode Rayleigh waves. Additional analysis of synthetic models, using a combination of LLSI and the neighbourhood algorithm, shows that if there was a low-velocity zone such as that reported by Priestley in 1999, our analysis procedure would have found it.
Keeping Farmers on the Land: Adding Value in Agriculture in the Veneto Region of Italy

Italy's relatively small area, high population density, and high land and labor costs have created the challenges of ensuring profitably for agricultural producers, slowing urban encroachment onto arable land, and keeping farm families on land that has been handed down within the families for generations. As part of the solution to these issues, the European Union is enacting policies to reduce producer dependence on direct subsidies while increasing the competitiveness of agricultural products and returns to producers, reinvigorating rural communities, and encouraging environmentally sound production methods. These regulations provide incentives for producers to add value to their products by obtaining legal recognition of typical products, participating in agritourism, and helping to promote traditional products for regional food systems. This paper examines how E.U. and national policies are encouraging farmers in the Veneto region of Italy to adopt an agricultural production model that encourages limited production of high-quality, high-value products and more diversified land use.