cssi/SciSciGPT-SciSciNet huggingface dataset:
Asymmetric Price Adjustment and Consumer Search: An Examination of the Retail Gasoline Market

It has been documented that retail gasoline prices respond more quickly to increases in wholesale price than to decreases. However, there is very little theoretical or empirical evidence identifying the market characteristics responsible for this behavior. This paper presents a new theoretical model of asymmetric adjustment that empirically matches observed retail gasoline price behavior better than previously suggested explanations. I develop a “reference price” consumer search model that assumes consumers’ expectations of prices are based on prices observed during previous purchases. The model predicts that consumers search less when prices are falling. This reduced search results in higher profit margins and a slower price response to cost changes than when margins are low and prices are increasing. Following the predictions of the theory, I use a panel of gas station prices to estimate the response pattern of prices to a change in costs. Unlike previous empirical studies I focus on how profit margins (in addition to the direction of the cost change) affect the speed of price response. Estimates are consistent with the predictions of the reference price search model, and appear to contradict previously suggested explanations of asymmetric adjustment.
An optimization-based framework for automated market-making

We propose a general framework for the design of securities markets over combinatorial or infinite state or outcome spaces. The framework enables the design of computationally efficient markets tailored to an arbitrary, yet relatively small, space of securities with bounded payoff. We prove that any market satisfying a set of intuitive conditions must price securities via a convex cost function, which is constructed via conjugate duality. Rather than deal with an exponentially large or infinite outcome space directly, our framework only requires optimization over a convex hull. By reducing the problem of automated market making to convex optimization, where many efficient algorithms exist, we arrive at a range of new polynomial-time pricing mechanisms for various problems. We demonstrate the advantages of this framework with the design of some particular markets. We also show that by relaxing the convex hull we can gain computational tractability without compromising the market institution's bounded budget.
BREAKFAST OF CHAMPIONS? THE SCHOOL BREAKFAST PROGRAM AND THE NUTRITION OF CHILDREN AND FAMILIES

We use the National Health and Nutritional Examination Survey (NHANES) III to examine the effect of the availability of the school breakfast program (SBP). Our work builds on previous research in four ways: First, we develop a transparent difference-in-differences strategy to account for unobserved differences between students with access to SBP and those without. Second, we examine serum measures of nutrient in addition to intakes based on dietary recall data. Third, we ask whether the SBP improves the diet by increasing/or decreasing the intake of nutrients relative to meaningful threshold levels. Fourth, we examine the effect of the SBP on other members of the family besides the school-aged child. We have three main findings. First, the SBP helps students build good eating habits: SBP increases scores on the healthy eating index, reduces the percentage of calories from fat, and reduces the probability of low fiber intake. Second, the SBP reduces the probability of serum micronutrient deficiencies in vitamin C, vitamin E, and folate, and it increases the probability that children meet USDA recommendations for potassium and iron intakes. Since we find no effect on total calories these results indicate that the program improves the quality of food consumed. Finally, in households with school-aged children, both preschool children and adults have healthier diets and consume less fat when the SBP is available. These results suggest that school nutrition programs may be an effective way to combat both nutritional deficiencies and excess consumption among children and their families.
The Value of Life and the Rise in Health Spending

Over the past half century, Americans spent a rising share of total economic resources on health and enjoyed substantially longer lives as a result. Debate on health policy often focuses on limiting the growth of health spending. We investigate an issue central to this debate: Is the growth of health spending a rational response to changing economic conditions—notably the growth of income per person? We develop a model based on standard economic assumptions and argue that this is indeed the case. Standard preferences— of the kind used widely in economics to study consumption, asset pricing, and labor supply—imply that health spending is a superior good with an income elasticity well above one. As people get richer and consumption rises, the marginal utility of consumption falls rapidly. Spending on health to extend life allows individuals to purchase additional periods of utility. The marginal utility of life extension does not decline. As a result, the optimal composition of total spending shifts toward health, and the health share grows along with income. In projections based on the quantitative analysis of our model, the optimal health share of spending seems likely to exceed 30 percent by the middle of the century.
Time in careers - careers in time

This article deals first with the temporal patterns of everyday career activities - time in careers - and then with the life-long career line - careers in time. In the former, it introduces the concept of grandmother time and uses telecommuting as an example. In the latter, it builds on the concept of a life-stage responsive career and uses the academic career as an example. The article argues that the accepted notions of time in both daily activities and the life course need serious modification if people are to be productive in the public professional-occupational world as well as in the private world of family and community.
Achieving a decision paradigm for distributed warfare resource management

The ability to optimally manage distributed warfare assets for collaborative operation significantly increases our military advantage. The primary results include enhanced situational awareness and improvements in fire control, engagement support, operational planning, combat reaction times, threat prioritization, and the list continues. Bettering the use of sensors and weapons in concert with one another— effectively creating a system of distributed systems—provides major payoffs.
Effectiveness of Tongue-lip Adhesion for Obstructive Sleep Apnea in Infants With Robin Sequence Measured by Polysomnography.

Objective: Tongue-lip adhesion (TLA) is commonly used to relieve obstructive sleep apnea (OSA) in infants with Robin sequence (RS), but few studies have evaluated its efficacy with objective measures. The purpose of this study was to measure TLA outcomes using polysomnography. Our hypothesis was that TLA relieves OSA in most infants. Methods: This is a retrospective study of infants with RS who underwent TLA from 2011 to 2014 and had at least a postoperative polysomnogram. Predictor variables included demographic and birth characteristics, surgeon, syndromic diagnosis, GILLS score, preoperative OSA severity, and clinical course. A successful outcome was defined as minimal OSA (apnea-hypopnea index score < 5) on postoperative polysomnogram and no need for additional airway intervention. Descriptive, bivariate, and regression statistics were computed, and statistical significance was set at P < .05. Results: Eighteen subjects who had TLA at a mean age of 28 ± 4.7 days were included. Thirteen (72.2%) had a c...
Trifluoromethyl- and difluoromethyl-β-lactams as useful building blocks for the synthesis of fluorinated amino acids, dipeptides, and fluoro-taxoids

Abstract Enantiopure 1-acyl-3-hydroxyl-4-CF 2 H-azetidin-2-ones and 1-acyl-3-hydroxy-4-CF 3 -azetidin-2-ones serve as versatile intermediates for the syntheses of CF 2 - and CF 3 -containing α-hydroxy-β-amino acids, dipeptides, and taxoid anticancer agents. Both enantiomers of 3-hydroxy-4-CF 2 H-β-lactams can be obtained in high yields through the diethylaminosulfur trifluoride (DAST) reaction of the corresponding enantiopure 4-formyl-β-lactam that is prepared through [2+2] cycloaddition of acetoxyketene to a 3-methyl-2-butenaldimine, followed by enzymatic optical resolution and ozonolysis. (+)-3-Hydroxy-4-CF 3 -β-lactams and (−)-3-hydroxy-4-CF 3 -β-lactams can also be readily obtained in enantiopure form through [2+2] cycloaddition of a CF 3 -imine with a ketene, followed by enzymatic optical resolution. Practical processes for the preparations of these enantiopure 3-hydroxy-4-R f -β-lactams as well as their synthetic applications are described.
The Effect of Water-Induced Stress To Enhance Hydrocarbon Recovery in Shale Reservoirs

Waterflooding has been an effective improved-oil-recovery (IOR) process for several decades. However, stress induced by waterflooding has not been well studied or documented. Water injection typically increases reservoir pressure and decreases reservoir temperature. The increase in reservoir pressure and decrease in reservoir temperature synergistically reduce the effective stress. Because of such decrease in stress, existing healed natural fractures can be reactivated and/or new fractures can be created. Similar effects can enhance hydrocarbon recovery in shale reservoirs. In this paper, we calculated the magnitude of water-injectioninduced stress with a coupled flow/geomechanics model. To evaluate the effect of water injection in the Bakken, a numerical-simulation study for a sector model was carried out. Stress changes caused by the volume created by the hydraulic fracture, water injection, and oil production were calculated. The Hoek-Brown failure criterion was used to compute rock-failure potential. Our numerical results for a waterflooding example show that during water injection, the synergistic effects of reservoir cooling and pore-pressure increase significantly promote rock failure, potentially reactivating healed natural macrofractures and/or creating new macrofractures, especially near an injector. The rock cooling can create small microfractures on the surface of the matrix blocks. In shale oil reservoirs, the numerical experiments indicate that stress changes during water injection can improve oil recovery by opening some of the old macrofractures and creating new small microfractures on the surface of the matrix blocks to promote shallow water invasion into the rock matrix. Furthermore, the new microfractures provide additional interface area between macrofractures and matrix to improve oil drainage when using surfactant and CO2 enhanced-oil-recovery techniques. These positive effects are particularly important farther away from the immediate vicinity of the hydraulic fracture, which is where much of the undrained oil resides.
Malaises du nourrisson Diagnostic et prise en charge

Resume L'expression « malaise du nourrisson » recouvre une gamme d'accidents tres large en type et en gravite, mais dont aucun ne doit etre neglige (valeur d'avertissement). Les principaux signes cliniques sont : pâleur ou cyanose, irregularites respiratoires, hypotonie, perte de conscience. Leur intensite et leur duree constituent la gravite du malaise : du malaise bref et leger jusqu'au malaise profond et prolonge exigeant une reanimation medicale en regle. Meme en l'absence de sequelles physiques pour l'enfant, l'anxiete reactionnelle de la famille doit etre prise en charge. Il faut s'obstiner a obtenir un diagnostic etiologique immediat (prise en charge) ou secondaire (prevention des recidives). L'interrogatoire de l'entourage a une importance fondamentale. L'examen clinique minutieux est suivi d'examens complementaires, en general en milieu hospitalier, completes au fur et a mesure de l'orientation diagnostique. L'etiologie peut paraitre claire dans un contexte connu ou d'une evidence suffisante : tableau infectieux severe, cardiopathies congenitales cyanogenes, maltraitance, reflux gastro-œsophagien (RGO), hyperreactivite vagale (HRV), association RGO/HRV. Il peut aussi s'agir de l'accident inaugural d'une pathologie ignoree, debutante, ou jusque-la larvee : cardiopathies obstructives gauches, dysrythmies, urgences neurologiques, hypoglycemie (maladies metaboliques). Certains malaises peuvent etre initialement inexpliques : il faut apprendre aux parents la reanimation d'urgence, organiser un suivi, refaire un bilan a distance. En cas de malaise inexplique ou recidivant malgre traitement, on peut proposer a la famille la mise sous moniteur a domicile. Le traitement est adapte a chaque etiologie avec l'aide des specialistes concernes. Malgre le succes du couchage sur le dos dans la prevention des morts subites du nourrisson, de nombreuses autres causes de malaise subsistent, dont certaines peuvent avoir une issue fatale. Il faut donc ne negliger aucun malaise, prendre au serieux les temoins de l'accident, et s'obstiner a faire un diagnostic etiologique, pour eviter une recidive.
Hydrothermal synthesis of single crystals of transition metal vanadates in the glaserite phase

Abstract A series of transition metal vanadate crystals were prepared using a high temperature (580 °C) hydrothermal method. The compounds all had the general formula A 2 AEM (VO 4 ) 2 ( A =K, Na, Li; AE =Ba, Sr; M =Co, Fe, Mn). They are all variations of the glaserite structural type and range in symmetry from P- 3 m 1 to P -3 to P 2 1 / c . Most of the derivatives contain a planar three-fold rotation operation, making them possible spin frustration candidates. Single crystal structural analyses were performed on many of the derivatives to obtain a detailed understanding of the distortions of the tetrahedral building blocks that accommodate the symmetry distortions. A hydrothermal growth method was developed to grow high quality single crystals of sizes up to 2–3 mm/edge. This method can be generalized for large crystal growth to enable magnetic and neutron diffraction studies that require relatively large single crystals.
A simple deterministic algorithm for guaranteeing the forward progress of transactions

This paper describes a remarkably simple deterministic (not probabilistic) contention-management algorithm for guaranteeing the forward progress of transactions - avoiding deadlocks, livelocks, and other anomalies. The transactions must be finite (no infinite loops), but on each restart, a transaction may access different shared-memory locations. The algorithm supports irrevocable transactions as long as the transaction satisfies a simple ordering constraint. In particular, a transaction that accesses only one shared-memory location is never aborted. The algorithm is suitable for both hardware and software transactional-memory systems. It also can be used in some contexts as a locking protocol for implementing transactions "by hand." HighlightsA remarkably simple algorithm can guarantee the forward progress of transactions.The algorithm supports irrevocable transactions.The algorithm is suitable for hardware or software transactional-memory systems.The algorithm can be used as a locking protocol.
Semi-supervised prediction of gene regulatory networks using machine learning algorithms

Use of computational methods to predict gene regulatory networks (GRNs) from gene expression data is a challenging task. Many studies have been conducted using unsupervised methods to fulfill the task; however, such methods usually yield low prediction accuracies due to the lack of training data. In this article, we propose semi-supervised methods for GRN prediction by utilizing two machine learning algorithms, namely, support vector machines (SVM) and random forests (RF). The semi-supervised methods make use of unlabelled data for training. We investigated inductive and transductive learning approaches, both of which adopt an iterative procedure to obtain reliable negative training data from the unlabelled data. We then applied our semi-supervised methods to gene expression data of Escherichia coli and Saccharomyces cerevisiae, and evaluated the performance of our methods using the expression data. Our analysis indicated that the transductive learning approach outperformed the inductive learning approach for both organisms. However, there was no conclusive difference identified in the performance of SVM and RF. Experimental results also showed that the proposed semi-supervised methods performed better than existing supervised methods for both organisms.
Isonitrile alkylations: a rapid route to imidazo[1,5-a]pyridines

Metalated arylmethylisonitriles readily add to 2-chloropyridines to afford imidazo[1,5-a]pyridines. Analogous additions to imidoyl chlorides and a chloroquinoline provide imidazoles and an imidazo[1,5-a]quinolone which, like imidazo[1,5-a]pyridines, are valuable heterocycles for pharmaceutical synthesis.
Jet Production and QCD at High Energy Colliders

Selected quantum chromodynamics (QCD) measurements performed at the Fermilab Run II Tevatron p ¯ p collider ( √ s = 1.96 TeV) by CDF and D0 collaborations, at the LHC pp collider ( √ s = 7 and 8 TeV) by CMS and ATLAS collaborations, and at HERAe ± p collider ( √ s = 300 and 314 GeV) by H1 and ZEUS collaborations are presented. The inclusive jet, dijet production and threejet cross section measurements are used to test perturbativ e QCD calculations, constrain parton distribution function determinations, and extract values of the strong coupling constant. Events with W/Z+jets production are used to measure many kinematic distributions allowing extensive testing and tuning predictions from next-to-leading-orde r (NLO) perturbative QCD (pQCD) and Monte-Carlo event generators. The diphoton production cross-sections check the validity of the NLO pQCD predictions, soft-gluon resummation methods implemented in theoretical calculations, and contributions from the parton-to-photon fragme ntation diagrams. The photon+b-jet cross-section measurements reveal an inability of NLO perturbative pQCD calculations to describe spectrum at high transverse momentum. Events with inclusive production of vector boson (γ/W/Z) and ≥ 2 jets are used to study increasingly important phenomenon of multiple parton interactions, measure an effective interaction cross sect ion, and limit existing models.
Less Is More? Implications of Regulatory Capture for Natural Resource Depletion

Well-designed regulation can check politically driven ineciencies, but it can also ex- acerbate distortions if politicians capture the regulators. We examine the consequences of strengthening India's electricity transmission regulatory structure for groundwater ex- traction, where electricity is the key input, and we nd evidence of regulatory capture by politicians. Guided by our model, in which politicians of national and regional parties compete for parliamentary seats, we show that empowering regulators ampli ed distortions in groundwater extraction in favor of national candidates, who have greater incentives and abilities to co-opt the regulators. Using nationally representative groundwater data from India for 1996-2006, we estimate that regulatory capture led to a 2.75 meter additional de- cline in water tables in closely-contested constituencies won by national parties' candidates. The short-term cost in closely-contested regional constituencies is around an 18 percent re- duction in agricultural production.
Unitary Cayley graphs of Dedekind domain quotients

Abstract If X is a commutative ring with unity, then the unitary Cayley graph of X , denoted G X , is defined to be the graph whose vertex set is X and whose edge set is { { a , b } : a − b ∈ X × } . When R is a Dedekind domain and I is an ideal of R such that R / I is finite and nontrivial, we refer to G R / I as a generalized totient graph . We study generalized totient graphs as generalizations of the graphs G Z / ( n ) , which have appeared recently in the literature, sometimes under the name Euler totient Cayley graphs . We begin by generalizing to Dedekind domains the arithmetic functions known as Schemmel totient functions, and we use one of these generalizations to provide a simple formula, for any positive integer m , for the number of cliques of order m in a generalized totient graph. We then proceed to determine many properties of generalized totient graphs such as their clique numbers, chromatic numbers, chromatic indices, clique domination numbers, and (in many, but not all cases) girths. We also determine the diameter of each component of a generalized totient graph. We correct one erroneous claim about the clique domination numbers of Euler totient Cayley graphs that has appeared in the literature and provide a counterexample to a second claim about the strong domination numbers of these graphs.
Comparison of costs for solar electric sources with diesel generators in remote locations

Three alternative sources for generating power in remote regions of the world are discussed. These include diesel-electric, photovoltaic and solar thermal-electric devices. Fuel cost, and more specifically, transportation costs of that fuel, dramatically determine which device will be most cost effective over a ten-year period under specific conditions. In areas where fuel is readily available, diesel still appears to be the best alternative, financially. Even today, however, solar-thermal generators appear to make sense in a number of realistic scenarios, especially those involving developing countries. Photovoltaics do not yet seem to be competitive, but technical advances may in fact change this in the future. Cultural factors must also be taken into account when choosing a device. These comparisons are all represented graphically and numerically. 7 references.
PREDICTION MARKETS IN THE LABORATORY

Prediction markets are becoming an ever more popular method for aggregating disparate information. Companies use prediction markets to forecast sales, release dates, and other internal activities. Recently, several well-known economists have argued that government ought to eliminate impediments to unleashing the power of prediction markets broadly. This survey paper looks at the laboratory experiments which provide part of the scientific justification for using prediction markets. These systems work because people who have private knowledge can use this “insider information” in the market, but doing so causes the price to reflect these data. Starting with early experiments that show markets can, under certain circumstances, aggregate information, we discuss the robustness of prediction markets to various design features. We also discuss places where performance does not match rhetoric and briefly look at experimental comparisons of alternative information aggregating institutions. Another issue consistently raised regarding the implementation of prediction markets is the degree to which traders can manipulate prices and thus the information gleaned. By following a series of experiments on manipulation, we present the circumstances that are and are not sufficient for manipulation attempts to be successful. Finally, we offer suggestions on where we believe future experiments are needed in this area.
Implementation of general background electromagnetic fields on a periodic hypercubic lattice

Nonuniform background electromagnetic fields, once implemented in lattice quantum chromodynamics calculations of hadronic systems, provide a means to constrain a large class of electromagnetic properties of hadrons and nuclei, from their higher electromagnetic moments and charge radii to their electromagnetic form factors. We show how nonuniform fields can be constructed on a periodic hypercubic lattice under certain conditions and determine the precise form of the background $U(1)$ gauge links that must be imposed on the quantum chromodynamics gauge-field configurations to maintain periodicity. Once supplemented by a set of quantization conditions on the background-field parameters, this construction guarantees that no nonuniformity occurs in the hadronic correlation functions across the boundary of the lattice. The special cases of uniform electric and magnetic fields, a nonuniform electric field that varies linearly in one spatial coordinate (relevant to the determination of quadruple moment and charge radii), nonuniform electric and magnetic fields with given temporal and spatial dependences (relevant to the determination of nucleon spin polarizabilities) and plane-wave electromagnetic fields (relevant to the determination of electromagnetic form factors) are discussed explicitly.
Middle-class flight from post-Katrina New Orleans: A theoretical analysis of inequality and schooling

Abstract We present a model of urban resilience where the pattern of disaster recovery is defined by forcibly evacuating the population of a city and then allowing people to return voluntarily. The model predicts the post-disaster population composition of a city, changes in its income distribution and citizen welfare, and changes in the level of public goods. Plausible ex-ante assumptions about urban characteristics lead to a post-disaster city that is smaller, more skill-intensive, and with higher mean educational attainment. The evolution of income inequality is more complex, even though unskilled wages rise, middle-class flight may cause income distribution to worsen. The analysis of disasters’ long term impact on fiscal structure and on demographic, income, and human capital distribution, illustrates the interplay of major determinants of resilience after a natural disaster. A stylized New Orleans around the time of its 2005 Katrina disaster is incorporated for realism and used as an example throughout. Predicted changes are broadly consistent with observed effects of Katrina on New Orleans.
Gold/gallium-catalyzed annulation of 1,3-dicarbonyl compounds and cyclopropylacetylenes for synthesis of substituted cyclopentenes

An efficient synthesis of substituted cyclopentenes through gold/gallium-catalyzed annulation of 1,3-dicarbonyl compounds and cyclopropylacetylenes is achieved. This tandem reaction consists of a gold-catalyzed Nakamura reaction, a catalytic dienol–enone tautomerization, and a gallium-catalyzed vinylcyclopropane (VCP) rearrangement.
How a Race to the Bottom Can Make You Fat

This article measures the effect of fiscal competition on obesity rates in the United States through education and health spending. We hypothesize that fiscal competition to attract firms results i...
Bounding the Space of Holographic CFTs with Chaos

Thermal states of quantum systems with many degrees of freedom are subject to a bound on the rate of onset of chaos, including a bound on the Lyapunov exponent, λ L ≤ 2π/β. We harness this bound to constrain the space of putative holographic CFTs and their would-be dual theories of AdS gravity. First, by studying out-of-time-order four-point functions, we discuss how λ L = 2π/β in ordinary two-dimensional holographic CFTs is related to properties of the OPE at strong coupling. We then rule out the existence of unitary, sparse two-dimensional CFTs with large central charge and a set of higher spin currents of bounded spin; this implies the inconsistency of weakly coupled AdS3 higher spin gravities without infinite towers of gauge fields, such as the SL(N) theories. This fits naturally with the structure of higher-dimensional gravity, where finite towers of higher spin fields lead to acausality. On the other hand, unitary CFTs with classical W ∞ [λ] symmetry, dual to 3D Vasiliev or hs[λ] higher spin gravities, do not violate the chaos bound, instead exhibiting no chaos: λ L = 0. Independently, we show that such theories violate unitarity for |λ| > 2. These results encourage a tensionless string theory interpretation of the 3D Vasiliev theory.
3D seismic image processing for faults

ABSTRACTNumerous methods have been proposed to automatically extract fault surfaces from 3D seismic images, and those surfaces are often represented by meshes of triangles or quadrilaterals. However, extraction of intersecting faults is still a difficult problem that is not well addressed. Moreover, mesh data structures are more complex than the arrays used to represent seismic images, and they are more complex than necessary for subsequent processing tasks, such as that of automatically estimating fault slip vectors. We have represented a fault surface using a simpler linked data structure, in which each sample of a fault corresponded to exactly one seismic image sample, and the fault samples were linked above and below in the fault dip directions, and left and right in the fault strike directions. This linked data structure was easy to exchange between computers and facilitated subsequent image processing for faults. We then developed a method to construct complete fault surfaces without holes using thi...
Management of Difficult Cases of Autoimmune Hepatitis

Autoimmune hepatitis (AIH) is a complex autoimmune disease characterized by immune-mediated destruction of hepatic parenchyma which can result in cirrhosis, liver failure, and death. Current American Association for the Study of Liver Diseases (AASLD) and European Association for the Study of Liver (EASL) guidelines recommend corticosteroids alone or in combination with azathioprine as first-line treatment strategies. However, a significant proportion of patients may not be able to tolerate or achieve complete biochemical response with these options. In this article, we discuss approaches to these patients and other challenging AIH patient groups such as the asymptomatic, pregnant, elderly, and liver transplant recipients.
Layer Number Dependence of Li(+) Intercalation on Few-Layer Graphene and Electrochemical Imaging of Its Solid-Electrolyte Interphase Evolution.

A fundamental question facing electrodes made out of few layers of graphene (FLG) is if they display chemical properties that are different to their bulk graphite counterpart. Here, we show evidence that suggests that lithium ion intercalation on FLG, as measured via stationary voltammetry, shows a strong dependence on the number of layers of graphene that compose the electrode. Despite its extreme thinness and turbostratic structure, Li ion intercalation into FLG still proceeds through a staging process, albeit with different signatures than bulk graphite or multilayer graphene. Single-layer graphene does not show any evidence of ion intercalation, while FLG with four graphene layers displays limited staging peaks, which broaden and increase in number as the layer number increases to six. Despite these mechanistic differences on ion intercalation, the formation of a solid–electrolyte interphase (SEI) was observed on all electrodes. Scanning electrochemical microscopy (SECM) in the feedback mode was used ...
Uranium Isotopic Fractionation Induced by U(VI) Adsorption onto Common Aquifer Minerals.

Uranium groundwater contamination due to U mining and processing affects numerous sites globally. Bioreduction of soluble, mobile U(VI) to U(IV)-bearing solids is potentially a very effective remediation strategy. Uranium isotopes (238U/235U) have been utilized to track the progress of microbial reduction, with laboratory and field studies finding a ∼1‰ isotopic fractionation, with the U(IV) product enriched in 238U. However, the isotopic fractionation produced by adsorption may complicate the use of 238U/235U to trace microbial reduction. A previous study found that adsorption of U(VI) onto Mn oxides produced a −0.2‰ fractionation with the adsorbed U(VI) depleted in 238U. In this study, adsorption to quartz, goethite, birnessite, illite, and aquifer sediments induced an average isotopic fractionation of −0.15‰ with the adsorbed U(VI) isotopically lighter than coexisting aqueous U(VI). In bicarbonate-bearing matrices, the fractionation depended little on the nature of the sorbent, with only birnessite pro...
Work Requirements in Public Housing: Impacts on Tenant Employment and Evictions

AbstractIn recent years, many have debated adopting work requirements in the public housing program, and a limited number of public housing agencies (PHA) have implemented these policies through the flexibility provided by the Moving to Work program. One such agency—the Charlotte Housing Authority (CHA)—has implemented a work requirement across five (of 15) public housing developments that mandates households to work 15 hr weekly or face sanctions. This article evaluates this policy and presents the first empirical analysis on the outcomes of a work requirement on employment and evictions. We find that, following work requirement enforcement, the percentage of impacted households paying minimum rent (a proxy for nonemployment) decreased versus a comparison group. Analysis of additional data on both employment and hours worked indicates similar results regarding employment gains, but no increase in average hours worked. We find no evidence that work requirement sanctions increased evictions, and very modes...
Stable determination of (Brune) stress drops

The Brune stress drop, σB, is generally calculated from two spectral observables: Ω0, the zero-frequency level of the far-field displacement amplitude spectrum, and vc, the corner frequency of that spectrum. σB takes the form σB=hΩvc³,(a), where h contains kinematic factors. In some recent studies, other estimates of the stress drop, such as the dynamic stress drop and the apparent stress, are found to be more stable and/or reliable than σB. We find that these apparent shortcomings of σB can be remedied if we replace the dependence of σB on vc as a directly determined spectral observable with a dependence on a parameter which can be determined more reliably and which appears linearly (instead of as the third power) in the expression for σB. This observable is J, the integral of the square of the ground velocity, which, by Parseval's theorem, is the second moment of the power spectrum. For spectra from broadband seismographs, the determination of J is totally objective; it is an integral for which the integrand approaches zero at both limits. For Brune's model, vc³ = qJ/(Ω0²) with q = 1/(2π³), and equation (a) becomes σB=hqJ/(Ω0) (b). If the P-wave contribution to the radiated energy as well as the angular dependence of J are neglected, the right-hand side of equation (b) is a constant multiple of the apparent stress. Hence, studies which show that apparent stress determinations provide more robust estimates of the stress drop than σB determined through equation (a) support evaluating σB through equation (b).
Synthesis and Anticancer Activity of All Known (−)-Agelastatin Alkaloids

The full details of our enantioselective total syntheses of (−)-agelastatins A–F (1–6), the evolution of a new methodology for synthesis of substituted azaheterocycles, and the first side-by-side e...
(Tosylimino)phenyl-λ3-iodane as a Reagent for the Synthesis of Methyl Carbamates via Hofmann Rearrangement of Aromatic and Aliphatic Carboxamides

A new, mild procedure for the Hofmann rearrangement of aromatic and aliphatic carboxamides using (tosylimino)phenyl-λ3-iodane, PhINTs, as a reagent is reported. Because of the mild reaction conditions, this method is particularly useful for the Hofmann rearrangement of substituted benzamides, which usually afford complex reaction mixtures with other hypervalent iodine oxidants. The mild reaction conditions and high selectivity in the reaction of carboxamides with PhINTs allow the isolation of the initially formed labile isocyanates or their subsequent conversion to stable carbamates by treatment with alcohols.
Stress Relaxation Studies of Scission in Rubber Vulcanizates

The method of stress relaxation has been used to study oxidative scission in crosslinked rubbers of five different chain structures. Each chain structure was crosslinked by sulfur and by a nonsulfur-containing agent. Among the sulfur-cured vuleanizates the rate of scission varied very significantly with chain structure in spite of the presence of sulfur crosslinks in each. On the contrary, for natural rubber, GR-S, and butyl rubber, the rates of scission of the sulfur cures were not very different from the corresponding sulfurless cures. It was concluded that in these three cases the scission reactions occur predominantly along the network chains as opposed to scission at the crosslinked site.
Some Physical Properties of Elastomers at Low Temperature

Little has been published concerning the effect of low temperature on the elasticity of rubbers. Since in many applications this is the only property which justifies their use, some attention must be paid to this problem. Rubbers can be characterized by the temperature at which they become brittle and by the width of the transition region. The sharpness of the transition between the elastic and the glassy states is greatest when the testing time is long compared to the molecular relaxation times. Other physical factors such as sample shape, stress at which the modulus is calculated, and the previous history of the sample affect the absolute nature of the elastic properties measured. A test is described which gives the values of the elastic constants at slow rates of extension, at moderate extensions, on previously flexed samples. For these conditions the superiority of gum stocks at low temperature decrease in the order polybutadiene, natural rubber, Butyl, Neoprene FR. The comparative values of the stocks can be changed by compounding variations. Addition of plasticizer shifts the relative modulus vs. temperature curve down the temperature scale without producing a significant change in shape. Addition of reinforcing materials decreases the sharpness of the transition without changing the position of the curve.
Push or Pull? Auctioning Supply Contracts

Consider a buyer, facing uncertain demand, who sources from multiple suppliers via online procurement auctions (open descending price-only auctions). The suppliers have heterogeneous production costs, which are private information, and the winning supplier has to invest in production capacity before the demand uncertainty is resolved. The buyer chooses to offer a push or pull contract, for which the single price and winning supplier are determined via the auction. We show that, with a pull contract, the buyer does not necessarily benefit from a larger number of suppliers participating in the auction, due to the negative effect of supplier competition on the incentive of supplier capacity investment. We thus propose an enhanced pull mechanism that mitigates this effect with a floor price. We then analyze and compare the outcomes of auctions for push and (enhanced) pull contracts, establishing when one form is preferred over the other based on the buyer's profits. We also compare our simple, price-only push and pull contract auctions to the optimal mechanisms, benchmarking the performance of the simple mechanisms as well as establishing the relative importance of auction design and contract design in procurement auctions.
On the Definition of an Infinite Number.

(1903). On the Definition of an Infinite Number. The American Mathematical Monthly: Vol. 10, No. 6-7, pp. 154-155.
Beam criterion for atmospheric propagation

A criterion is introduced for testing whether a beam (monochromatic or partially coherent) retains its beam-like form after it propagates any particular distance through the turbulent atmosphere. Several examples are given.
Rubber Analysis of Plants in South Carolina

Abstract In 1930 and 1931 some plants growing in the vicinity of Clemson, South Carolina, were collected and analyzed for the presence of rubber. The plants were collected and identified by M. A. Rice, the chemical tests being made by the other two authors. The results are presented below. The figures given at the right show the percentage of rubber in each case. All determinations were made on a basis of air-dry weight.
Molecular clustering based on ERΑ and EIG121 predicts survival in high-grade serous carcinoma of the ovary/peritoneum

Assessment of estrogen receptor (ER) expression by immunohistochemistry has yielded inconsistent results as a prognostic indicator in ovarian carcinoma. In breast and endometrial carcinomas, panels of estrogen-induced genes have shown improved prognostic capability over the use of ER immunohistochemistry alone. For both breast and endometrial cancers, overexpression of estrogen-induced genes is associated with better prognosis. We hypothesized that analysis of a panel of estrogen-induced genes can predict the outcome in ovarian carcinoma and potentially differentiate between tumors of varying hormonal responsiveness. From a cohort of 219 women undergoing ovarian cancer surgery from 2004 to 2007, 83 patients were selected for inclusion. All patients had advanced stage ovarian/primary peritoneal high-grade serous carcinoma and underwent primary surgical debulking, followed by adjuvant treatment with platinum and taxane agents. The expression of ERα and six genes known to be induced by estrogen in the female reproductive tract (namely EIG121, sFRP1, sFRP4, RALDH2, PR, and IGF-1) was measured using quantitative RT-PCR. Unsupervised cluster analyses were used to categorize patients as high or low gene expressors. Gene expression results were then compared with those for ER immunohistochemistry. Clusters were compared using χ(2) analyses, and Cox proportional hazards models were used to evaluate survival outcomes. The median follow-up time was 38.7 months (range: 1-68). A cluster defined by EIG121 and ERα segregated tumors into distinct groups of high and low gene expressors. Shorter overall survival (OS) was associated with high gene expression (HR 2.84 (1.11-7.30), P=0.03), even after adjustment for other covariates. No difference in ER immunohistochemistry expression was noted between gene clusters. In contrast to other hormonally driven cancers, high expression of ERα and the estrogen-induced gene EIG121 predicts shorter OS in patients with high-grade serous ovarian carcinoma. Such a biomarker panel may potentially be used to guide management with estrogen antagonists in this patient population.
The Impact of Recognition Versus Disclosure on Financial Information: A Preparer's Perspective

We investigate whether recognition on the face of the financial statements versus disclosure in the footnotes influences the amount that financial managers report for a contingent liability. Using an experiment with corporate controllers and chief financial officers, we find that financial managers in public companies expend more cognitive effort and exhibit less strategic bias under recognition than disclosure. This difference appears to be associated with capital market pressures experienced by public company managers as we find that both the cognitive effort and bias exhibited by private company managers are unaffected by placement. As a result, public company managers make higher liability estimates for recognized versus disclosed liabilities. Their liability estimates are similar to those of private company managers for recognition but lower than private company managers� estimates for disclosure. Our results have implications for auditors and financial statement users in evaluating recognized versus disclosed information for public and private companies.
The importance of the cathode plume and its interactions with the ion beam in numerical simulations of Hall thrusters

Numerical simulations with a 2-D axisymmetric multi-fluid plasma code illustrate the significance of the near-plume interactions in investigations of the anomalous electron transport in Hall thrusters. In our simulations, the transport of electrons is modeled using an anomalous collision frequency, νanom, yielding νanom ≈ ωce (i.e., the electron cyclotron frequency) in the near-plume region. We first show that restricting the anomalous collision frequency in this region to only within the ion beam, where the current density of ions is large, does not alter the plasma discharge in the Hall thruster as long as the interaction between the beam and the cathode plume is captured properly. These simulations suggest that electron transport occurs largely inside the beam. A second finding is on the significance of accounting for the ion acoustic turbulence (IAT), now known to occur in the vicinity of the cathode exit. We have included in our simulations a model of the IAT-driven anomalous collision frequency based on Sagdeev's model for saturation of the ion-acoustic instability. This implementation has allowed us to achieve excellent agreement with experimental measurements in the near plume of the H6 Hall thruster. Low frequency plasma oscillations similar in both magnitude and frequency to those found in the H6 thruster are recovered in our simulations when the model for the anomalous collision frequency in the cathode plume is included.
Calcium Ion Fluctuations Alter Channel Gating in a Stochastic Luminal Calcium Release Site Model

Stochasticity and small system size effects in complex biochemical reaction networks can greatly alter transient and steady-state system properties. A common approach to modeling reaction networks, which accounts for system size, is the chemical master equation that governs the dynamics of the joint probability distribution for molecular copy number. However, calculation of the stationary distribution is often prohibitive, due to the large state-space associated with most biochemical reaction networks. Here, we analyze a network representing a luminal calcium release site model and investigate to what extent small system size effects and calcium fluctuations, driven by ion channel gating, influx and diffusion, alter steady-state ion channel properties including open probability. For a physiological ion channel gating model and number of channels, the state-space may be between approximately $10^6-10^8$ elements, and a novel modified block power method is used to solve the associated dominant eigenvector problem required to calculate the stationary distribution. We demonstrate that both small local cytosolic domain volume and a small number of ion channels drive calcium fluctuations that result in deviation from the corresponding model that neglects small system size effects.
A DMP model of intercity trade

Job matching, a central feature of DMP theory, requires contacts between prospective employers and employees. This paper assumes that they may be either face-to-face and take place at city centers or via referrals from social contacts. The paper presents a model of an economy whose urban structure consists of cities of different types. All cities produce a non-tradeable final good using ranges of tradeable intermediate varieties. Each city has an internal spatial structure: individuals commute to the CBD in order to work, when employed, and to seek jobs, when unemployed. Hiring by each intermediate producing firm is subject to frictions, which are modeled in the Diamond–Mortensen–Pissarides fashion. City type is conferred by specialization in producing one of two types of intermediate varieties and there is intercity trade in intermediate varieties. The paper examines properties of equilibrium with intercity trade and its dependence on various parameters and their consequences for unemployment, output and welfare across the economy along a steady state. The model's use of international trade tools confers a central role to labor market tightness, akin to factor intensity. A natural dependence of unemployment on city size is generated. Equilibrium outcomes generically diverge from the planner's optimum: there exists mismatch generically. Socially optimal unemployment trades off the probability of employment to search costs of firms independently for each skill type and independently of city size. Socially optimal city sizes are independent of the matching model and therefore labor market tightness considerations but reflect both market size effects and the skill composition of the economy.