cssi/SciSciGPT-SciSciNet huggingface dataset:
Challenges associated with projecting urbanization-induced heat-related mortality.

Abstract Maricopa County, Arizona, anchor to the fastest growing megapolitan area in the United States, is located in a hot desert climate where extreme temperatures are associated with elevated risk of mortality. Continued urbanization in the region will impact atmospheric temperatures and, as a result, potentially affect human health. We aimed to quantify the number of excess deaths attributable to heat in Maricopa County based on three future urbanization and adaptation scenarios and multiple exposure variables. Two scenarios (low and high growth projections) represent the maximum possible uncertainty range associated with urbanization in central Arizona, and a third represents the adaptation of high-albedo cool roof technology. Using a Poisson regression model, we related temperature to mortality using data spanning 1983–2007. Regional climate model simulations based on 2050-projected urbanization scenarios for Maricopa County generated distributions of temperature change, and from these predicted changes future excess heat-related mortality was estimated. Subject to urbanization scenario and exposure variable utilized, projections of heat-related mortality ranged from a decrease of 46 deaths per year (− 95%) to an increase of 339 deaths per year (+ 359%). Projections based on minimum temperature showed the greatest increase for all expansion and adaptation scenarios and were substantially higher than those for daily mean temperature. Projections based on maximum temperature were largely associated with declining mortality. Low-growth and adaptation scenarios led to the smallest increase in predicted heat-related mortality based on mean temperature projections. Use of only one exposure variable to project future heat-related deaths may therefore be misrepresentative in terms of direction of change and magnitude of effects. Because urbanization-induced impacts can vary across the diurnal cycle, projections of heat-related health outcomes that do not consider place-based, time-varying urban heat island effects are neglecting essential elements for policy relevant decision-making.
Linear Dynamics of a Translating String on an Elastic Foundation

This paper examines the free and forced linear response of a string which is translating across an elastic foundation. Exact solutions are derived for the free vibration of the string which translates between fixed eyelets and across elastic foundations represented by a single interior spring and a uniform step foundation. Results illustrate the dependence of the string natural frequencies and mode shapes on the foundation stiffness, the foundation geometry, and the string translation speed
Perfluorooctanoic acid exposure triggers oxidative stress in the mouse pancreas

Perfluorooctanoic acid (PFOA) is used in the manufacture of many industrial and commercial products. PFOA does not readily decompose in the environment, and is biologically persistent. Human epidemiologic and animal studies suggest that PFOA exposure elicits adverse effects on the pancreas. While multiple animal studies have examined PFOA-mediated toxicity in the liver, little is known about the potential adverse effects of PFOA on the pancreas. To address this, we treated C57Bl/6 mice with vehicle, or PFOA at doses of 0.5, 2.5 or 5.0 mg/kg BW/day for 7 days. Significant accumulation of PFOA was found in the serum, liver and pancreas of PFOA-treated animals. Histopathologic examination of the pancreas revealed focal ductal hyperplasia in mice treated with 2.5 and 5.0 mg/kg BW/day PFOA, while inflammation was observed only in the high dose group. Elevated serum levels of amylase and lipase were observed in the 2.5 mg/kg BW/day PFOA treatment group. In addition, PFOA exposure resulted in a dose-dependent increase in the level of the lipid peroxidation product 8-iso-PGF2α and induction of the antioxidant response genes Sod1, Sod2, Gpx2 and Nqo1. Our findings provide additional evidence that the pancreas is a target organ for PFOA-mediated toxicity and suggest that oxidative stress may be a mechanism through which PFOA induces histopathological changes in the pancreas.
On nonlinear diffusion with multiplicative noise

Nonlinear diffusion is studied in the presence of multiplicative noise. The nonlinearity can be viewed as a "wall" limiting the motion of the diffusing field. A dynamic phase transition occurs when the system "unbinds" from the wall. Two different universality classes, corresponding to the cases of an "upper" and a "lower" wall, are identified and their critical properties are characterized. While the lower wall problem can be understood by applying the knowledge of linear diffusion with multiplicative noise, the upper wall problem exhibits an anomaly due to an effective long-ranged repulsion exerted by the wall.
Intramolecular nitrile oxide cycloaddition in the dihydrotropone series. A rapid entry into the bicyclo[5.3.0]decane and bicyclo[5.4.0]undecane ring systems

Abstract 1.8-Addition of terminally functionalized three and four carbon chains to tropone followed by intramolecular nitrile oxide cycloaddition provides highly functionalized bicyclo[5.3.0]decane and bicyclo[5.4.0]undecane products.
Practical issues in the design and execution of an emergency medicine research study

The planning and execution of a scientific research study can be a daunting prospect for the inexperienced investigator. This article attempts to break down the task into components, each of which can be conceptualized and executed independently, and makes recommendations for this structured approach. The article proceeds in a time-sequential fashion, beginning with the conception of the study and ending with the final publication of the study manuscript. The article emphasizes the importance of adequate study preparation and most of the discussion is devoted to development of the research question and hypothesis, review of the literature, study design and methodology and ethics committee issues. Data collection, results analysis, manuscript preparation and the peer review process are also discussed. This article is meant as a guideline for the less experienced researcher and reference to authoritative text is recommended highly.
Deformations of quasicoherent sheaves of algebras

Gerstenhaber and Schack [NATO Adv. Sci. Inst. Ser. C, Vol. 247, 1986] developed a deformation theory of presheaves of algebras on small categories. We translate their cohomological description to sheaf cohomology. More precisely, we describe the deformation space of (admissible) quasicoherent sheaves of algebras on a quasiprojective scheme X in terms of sheaf cohomology on X and X×X. These results are applied to the study of deformations of the sheaf DX of differential operators on X. In particular, in case X is a flag variety we show that any deformation of DX, which is induced by a deformation of OX, must be trivial. This result is used in [Lunts, Rosenberg, manuscript], where we study the localization construction for quantum groups.
A study of a new foundation model

The characteristics of a new foundation model, consisting of two spring layers interconnected by a shear layer, are studied. The study is conducted on the classical problem of a foundation subjected to a rigid stamp. In order to reduce the number of foundation constants to an absolutely necessary minimum, special attention is given to a possible dependence of the constants of the upper and lower spring layer, particularly to the spring constant ratio three which is suggested byReissner's foundation model. A comparison of the obtained pressure distributions with relevant experimental data seem to support the adoption of this value, thus reducing the number of foundation constants to two. Advantages of the presented model over other foundation models are pointed out.
Regulation and non-compliance : magnitudes and patterns for India's Factories Act

Noncompliance with regulations by enterprises is said to be rife in developing countries. Yet there is limited systematic evidence of the magnitude of noncompliance at the enterprise level. Making innovative use of two complementary data sources, this paper quantifies noncompliance for India's Factories Act without the question of illegality ever being raised directly with enterprises. The paper finds that more than twice as many firms are not complying as are complying. Further, the number of noncompliant firms is much larger than the number of firms adjusting out of the regulation. Thus noncompliance with the Factories Act is a key feature of the"missing middle"in India. The paper explores the main trends and patterns of noncompliance and highlights a number of key issues for further analytical and policy research. (This abstract was borrowed from another version of this item.) (This abstract was borrowed from another version of this item.)
Monochromator-interferometer combination for submillimeter astronomical spectrometry from aircraft.

A simple interferometer placed in front of a liquid helium cooled grating instrument was constructed; a spectral resolution of not less than 0.1/cm in the wavelength range of 64/cm (157 microns) was attained during observations from the NASA Kuiper Airborne Observatory. Spectra obtained on the planetary nebula NGC 7027 are shown.
Diversity-Oriented Synthesis of Azaspirocycles

Multicomponent condensation of N-diphenylphosphinoylimines, alkynes, zirconocene hydrochloride, and diiodomethane provides a rapid access to omega-unsaturated dicyclopropylmethylamines. These novel building blocks are converted into heterocyclic 5-azaspiro[2.4]heptanes, 5-azaspiro-[2.5]octanes, and 5-azaspiro[2.6]nonanes by means of selective ring-closing metathesis, epoxide opening, or reductive amination. The resulting functionalized pyrrolidines, piperidines, and azepines are scaffolds of considerable relevance for chemistry-driven drug discovery.
Exchange Rate and Political Risks, Again

We examine the effects of exchange rate and political risks on foreign direct investment (FDI) for multinationals. We examine FDI by U. S. firms at two levels: in all industries and on the subset of firms in manufacturing industries. When investing in developed economies, firms appear to consider past and present variation in exchange rates. When investing in less developed nations, past and present variation does not appear to weigh as heavily as present and future variation. Decreasing political risk increases FDI.
Documentation of a model action plan to deter illicit nuclear trafficking

Theft, illegal possession, smuggling, or attempted unauthorized sale of nuclear and radiological materials remains a worldwide problem. The Nuclear Smuggling International Technical Working Group (ITWG) has adopted a model action plan to guide investigation of these cases through a systematic approach to nuclear forensics. The model action plan was recently documented and provides recommendations concerning incident response, collection of evidence in conformance with required legal standards, laboratory sampling and distribution of samples, radioactive materials analysis, including categorization and characterization of samples, forensics analysis of conventional evidence, and case development including interpretation of forensic signatures.
Detection and mass characterization of terrestrial planets in the habitable zone with SIM PlanetQuest

SIM PlanetQuest is a space-borne Michelson interferometer with a nine meter baseline that will survey ~200 stars within 30 parsecs for terrestrial mass planets. Ultra-precise astrometric observations will reveal the gravitational wobble of the target star (due to a planetary companion) against an inertial frame of reference stars located within a 1.5 degree radius. Here, we report the results of multiple Monte Carlo simulations which have modeled SIM's ability to detect and determine the orbital parameters and masses of the terrestrial mass planets around its potential sample of target stars. We find that SIM will detect 80% of the planets in the 60 star sample. Out of those planets SIM detects, we will be able to estimate the masses of at least 50% of the planets to 30%. Whether SIM should observer 60 or 240 stars, will be aided by the results of the Kepler mission which will provide statistics on the frequency of terrestrial-mass planets around solar type stars. By determining the orbital phase of the planet, SIM will be able to assist TPF-C by telling it when to look to ensure that the planet will be outside the TPF-C 62 mas inner working angle. Furthermore, the masses determined by SIM will not suffer from the msini ambiguity inherent in radial velocity surveys.
The Role of Peer Influence in Churn in Wireless Networks

Subscriber churn remains a top challenge for wireless carriers. These carriers need to understand the determinants of churn to confidently apply effective retention strategies to ensure their profitability and growth. In this paper, we look at the effect of peer influence on churn and we try to disentangle it from other effects that drive simultaneous churn across friends but that do not relate to peer influence. We analyze a random sample of roughly 10 thousand subscribers from large dataset from a major wireless carrier over a period of 10 months. We apply survival models and generalized propensity score to identify the role of peer influence. We show that the propensity to churn increases when friends do and that it increases more when many strong friends churn. Therefore, our results suggest that churn managers should consider strategies aimed at preventing group churn. We also show that survival models fail to disentangle homophily from peer influence over-estimating the effect of peer influence.
Regulation of subprime mortgage products: An analysis of North Carolina's predatory lending law

This paper estimates the effect of North Carolina's high-cost mortgage law on the subprime mortgage market in that state. The results indicate that creditors sharply restricted lending to higher risk consumers in North Carolina following passage of the law. Creditors did not restrict lending in neighboring states or to lower risk consumers in North Carolina. These results suggest that the restriction in North Carolina was due to rationing in response to higher costs imposed by the law. The findings of this study are of importance beyond North Carolina. Other states and municipalities have proposed or passed similar or more restrictive laws. These laws risk taking back some of the gains in credit availability that lower income and higher risk consumers gained in the 1990s.
Heavy particle electroweak loop effects in extra-dimensional models with bulk neutrinos

Abstract One way to detect the presence of new particles in theories beyond the standard model is through their contribution to electroweak loop effects. We comment on the importance of a consistent inclusion of their mixing angles to ensure that the physical requirement of heavy particle decoupling is fulfilled. We illustrate our points by a detailed discussion of the lepton flavor changing effect μ → eγ , investigated recently by Kitano, in the Randall–Sundrum model. Our remarks are equally applicable to models with large compactified dimensions where bulk neutrinos are introduced to account for the observed neutrino oscillations.
Analytical GTO turn-off model under snubberless turn-off condition

Based on the analysis of numerical simulation results, an analytical turn-off model for the gate turn-off thyristor under snubberless condition is developed. The turn-off process predicted by the analytical model is in good agreement with numerical simulation.
Computing the integer programming gap

We determine the maximal gap between the optimal values of an integer program and its linear programming relaxation, where the matrix and cost function are fixed but the right hand side is unspecified. Our formula involves irreducible decomposition of monomial ideals. The gap can be computed in polynomial time when the dimension is fixed.
Reliability of Performance on the Test of Memory and Learning (TOMAL) by an Adolescent Learning Disability Sample.

The Test of Memory and Learning (TOMAL) is a recent comprehensive memory battery offered to neuropsychologists and standardized on a national sample of children ages 5 years through 19 years. The TOMAL Manual reports very high coefficient alpha internal consistency reliability coefficients for the standardization sample of "normal" children. In the current study, 99 adolescents (ages 12 to 18 years) diagnosed with various learning disabilities in the public schools were administered the TOMAL, and Cronbach's alpha was calculated based on the responses of these 99 adolescents. A matched sample was drawn from the standardization sample and alpha computed for this group. Alpha values in the two groups were highly similar across all 14 subtests. Although adolescents with learning disabilities often have memory deficits, their performance on the TOMAL tends to be as reliable as that of adolescents without learning disabilities.
Preparation of bridged bicycloalkanes via intramolecular [2+2] cycloadditions of ketenes a short total synthesis of (±)-clovene.

Abstract The preparation of a bridged bicyloalkane via an intramolecular ketene-olefin cycloaddition reaction in the context of a total synthesis of clovene is described.
Optimal design of digital IIR filters by model-fitting frequency response data

A new frequency-domain (FD) approach is presented for optimal estimation of rational transfer functions coefficients. The proposed method seeks to match any arbitrarily-shaped FD specifications in the least-squares sense. The desired specifications may be arbitrarily spaced in frequency. The design is performed directly in the digital domain, and no analog to digital transformation is necessary. The proposed method makes use of the inherent mathematical structure in this rational modeling problem to theoretically decouple the numerator and denominator estimation problems into two lower dimensional problems. The denominator criterion is nonlinear but possesses a weighted-quadratic structure, which is convenient for iterative optimization. The optimal numerator is found linearly by solving a set of simultaneous equations. The decoupled criteria retain the global optimality properties. The performance of the algorithm is demonstrated with some simulation examples. >
Making sense of non-Hermitian Hamiltonians

The Hamiltonian H specifies the energy levels and time evolution of a quantum theory. A standard axiom of quantum mechanics requires that H be Hermitian because Hermiticity guarantees that the energy spectrum is real and that time evolution is unitary (probability-preserving). This paper describes an alternative formulation of quantum mechanics in which the mathematical axiom of Hermiticity (transpose +complex conjugate) is replaced by the physically transparent condition of space?time reflection ( ) symmetry. If H has an unbroken symmetry, then the spectrum is real. Examples of -symmetric non-Hermitian quantum-mechanical Hamiltonians are and . Amazingly, the energy levels of these Hamiltonians are all real and positive!Does a -symmetric Hamiltonian H specify a physical quantum theory in which the norms of states are positive and time evolution is unitary? The answer is that if H has an unbroken symmetry, then it has another symmetry represented by a linear operator . In terms of , one can construct a time-independent inner product with a positive-definite norm. Thus, -symmetric Hamiltonians describe a new class of complex quantum theories having positive probabilities and unitary time evolution.The Lee model provides an excellent example of a -symmetric Hamiltonian. The renormalized Lee-model Hamiltonian has a negative-norm 'ghost' state because renormalization causes the Hamiltonian to become non-Hermitian. For the past 50 years there have been many attempts to find a physical interpretation for the ghost, but all such attempts failed. The correct interpretation of the ghost is simply that the non-Hermitian Lee-model Hamiltonian is -symmetric. The operator for the Lee model is calculated exactly and in closed form and the ghost is shown to be a physical state having a positive norm. The ideas of symmetry are illustrated by using many quantum-mechanical and quantum-field-theoretic models.
DC Bus Voltage Clamp Method to Prevent Over-Voltage Failures in Adjustable Speed Drives

The influences of PWM switching and long cable length on motor insulations have been discussed in numerous papers. This paper investigates their effect on the voltage insulation components inside an adjustable speed drive (ASD). This paper shows that high potential voltage insulation issue may exist on various components inside the ASD and cause earlier failures under very long cable or multiple drive conditions. A system model to describe this phenomenon is described in the paper. A dc bus voltage clamp circuit is proposed to reduce these voltage stresses. The effectiveness of this circuit is verified by both simulation and experimental results.
Microwave-promoted reactions: Intramolecular carbanilide cyclization to hydantoins employing barium hydroxide catalyst

Abstract Hydantoin ring formation via carbanilide cyclization is achieved in high yield with short reaction time by employing catalytic amounts of Ba(OH) 2 (anhydrous or octahydrate) in DMF under microwave irradiation. Evidence is provided that kinetic product 4 (trans, anti, cis stereochemistry) epimerizes to thermodynamic product 3 (trans, anti, trans stereochemistry).
The MINOS experiment

Abstract The MINOS (Main Injector Neutrino Oscillation Search) experiment will use the Main Injector neutrino beam to make high-precision oscillation measurements on all possible oscillation channels relevant to the atmospheric neutrino problem. Construction of the detector and the beamline are underway. Data acquisition with atmospheric neutrinos will begin in 2002 while the first beam neutrinos are expected in late 2004. While waiting for the beam neutrinos, MINOS will provide the first measurement oil the oscillation properties of atmospheric anti-neutrinos compared to neutrinos. This is possible due to the magnetic field in the detector.
Oblique corrections in technicolor with a scalar

Abstract We study a model in which the electroweak symmetry is dynamically broken by technicolor interactions and the symmetry-breaking is communicated to the quarks and leptons by a weak doublet of scalar fields. The scalars may be regarded as elementary or as light bound states arising from strong extended technicolor interactions. This model is unusual in that it can provide a heavy top quark without generating large flavor-changing neutral currents. Our work focuses on the model's phenomenology, particularly the oblique electroweak radiative corrections. We demonstrate that while oblique corrections and FCNC effects limit the allowed parameter space, the model remains viable. In particular, if the scalar is relatively heavy, the model can accomodate a wide range of top quark masses.
Accurate determination of the ionization energy in semiconductor detectors

Abstract The average energy g3 expended for electron-hole pair generation in silicon and germanium lithium-drifted detectors by gamma rays, electrons, and alpha particles has been measured as a function of temperature. These data indicate that the difference between eα and ee− in silicon is considerably less than previously reported, and in germanium eα ∼ ee−.
A haptic system for virtual prototyping of polygonal models

Virtual prototyping attempts to replace physical models with virtual models for the purpose of design evaluation. One task a virtual prototyping environment can address is the accessibility of the components of a mechanical system. In this paper, we demonstrate a haptics-based virtual prototyping system for finding collision-free paths for moving models in complex polygonal environments. The system can handle models and environments with hundreds of thousands of triangles, and augments innate human talents at searching for collision-free paths.
Polymer-supported synthesis of mono-substituted porphyrins

Abstract Anchoring of substituted benzaldehydes to soluble and insoluble polymers allows for the synthesis of mono-substituted tetraarylporphyrins without the production of di-, tri-, and tetra-substituted porphyrin side products. The exclusion of the aforementioned side products during the synthesis of mono-substituted tetraarylporphyrin acids greatly reduced the complexity during purification of the product.
A minimal covariant action for the free open spinning string field theory

Abstract The BRST transformations of the string fields of the free open spinning string is analyzed. After expanding the string fields into ghost zero modes the BRST transformations are diagonalized and it is found that in the Ramond sector the physical fields are contained in only two string fields. A minimal covariant classical action for both sectors is constructed. The component expansion of the string fields yields the correct set of physical and Stueckelberg fields which are needed to construct a covariant local action for the corresponding massless and massive states. This is explicitly verified for the first three mass-levels.
Formal syntheses of cryptophycin A and arenastatin A

Abstract Efficient formal syntheses of the tubulin binding antitumor agents cryptophycin A ( 1 ) and arenastatin A ( 2 ) are detailed. The readily available β-keto ester 4 was subjected to catalytic asymmetric hydrogenation, Frater alkylation, and selective functional group transformations to provide the silyl ether of octanoic acid methyl ester 3 , which is the key intermediate for the formal syntheses of the title compounds.
Length and Eigenvalue Equivalence

Two Riemannian manifolds are called eigenvalue equivalent when their sets of eigenvalues of the Laplace-Beltrami operator are equal (ignoring multiplicities). They are (primitive) length equivalent when the sets of lengths of their (primitive) closed geodesics are equal. We give a general construction of eigenvalue equivalent and primitive length equivalent Riemannian manifolds. For example we show that every finite volume hyperboli c n‐manifold has pairs of eigenvalue equivalent finite covers of arbitrar ily large volume ratio. We also show the analogous result for primitive length equivalence.
New mineralcorticoids in the syndrome of low-renin essential hypertension.

Abstract Patients with low-renin essential hypertension have certain features consistent with excessive mineralocorticoid activity. Because known mineralocorticoids are normal in the majority of low-renin essential hypertension patients, an unknown mineralocorticoid was sought in the urine of such patients. Using adrenalectomized rats to assay mineralocorticoids, urine extracts from patients with low-renin essential hypertension were found to contain more mineralocorticoid activity than could be accounted for by the known mineralocorticoids in the extract. The substances causing this unexplained mineralocorticoid activity were purified and then identified by mass spectral analysis as 16β-hydroxydehydroepiandrosterone (16/gb-OH-DHEA) and its 16-oxo-17β-ol isomer. That these steroids are in fact mineralocorticoids was confirmed by demonstrating that the synthetic compounds have mineralocorticoid potency l/40th that of aldosterone in the rat bioassay. Also, the mineralocorticoid effects of both the urine extracts and the synthetic steroids were blocked in the rat by spironolactone, a mineralocorticoid antagonist. The new mineralocorticoids appear to have clinical significance since they appeared in the urine in abnormally large quantities in 15 out of 15 patients with low-renin essential hypertension but only one out of 14 patients with hypertension and normal or high plasma renin activity.
X-ray astronomical spectroscopy

The current status of the X-ray spectroscopy of celestial X-ray sources, ranging from nearby stars to distant quasars, is reviewed. Particular emphasis is placed on the role of such spectroscopy as a useful and unique tool in the elucidation of the physical parameters of the sources. The spectroscopic analysis of degenerate and nondegenerate stellar systems, galactic clusters and active galactic nuclei, and supernova remnants is discussed.
Regioselective oxidations of equilenin derivatives catalyzed by a rhodium(III) porphyrin complex—contrast with the manganese(III) porphyrin

Abstract Equilenin acetate and dihydroequilenin acetate were oxidized with iodosobenzene and a rhodium(III) porphyrin catalyst. The selectivity of the reactions differs from that with the corresponding Mn(III) catalyst, or from that of free radical chain oxidation.
A QUOTIENT OF THE SET (BG,BU(n)) FOR A FINITE GROUP G OF SMALL RANK

Abstract Let Gp be a Sylow p-subgroup of the finite group G and let CharnG(Gp) represent the set of degree n complex characters of Gp that are the restrictions of class functions on G. We construct a natural map ψ G : [BG,BU(n)]→∏ p||G| Char n G (G p ) and prove that ψG is a surjection for all finite groups G that do not contain a subgroup isomorphic to ( Z /p) 3 for any prime p. We show, furthermore, that ψG is in fact a bijection for two types of finite groups G: those with periodic cohomology and those of odd order that do not contain a subgroup isomorphic to ( Z /p) 3 for any prime p.
Matrix isolation investigation of the interaction of lewis acids with Cr(CO)6 and Mo(CO)6

Abstract The matrix isolation technique has been employed for the study of the interaction between several Lewis acids and Cr(CO) 6 and Mo(CO) 6 . The twin jet codeposition of ClF with either of the metal hexacarbonyls gave rise to a single product absorption at 1974 cm −1 , which is indicative of a perturbed carbonyl stretching mode in a weakly bound molecular complex. No perturbed mode of the ClF subunit was detected, contrary to previous ClF studies. The singlet jet codeposition of either BF 3 or BCl 3 with these metal carbonyls gave no indication of complex formation. These results are discussed, as is the potential implication for Lewis acid-induced alkyl migration reactions.
Trimethylsilyl halides: Effective reagents for the synthesis of β-halo amino acid derivatives

Abstract β-Halogen alanine derivatives are prepared in moderate yields in one step from the corresponding serine compound and trimethylsilyl halide.
Casing Deflection and Centralizer Spacing Calculations

In this paper, equations for calculating casing deflection and determining casing centralizer spacing are derived for 1D, 2D, and 3D wellbores. The load-deflection differential equation for a span of casing between two centralizers is solved by use of the fixed-ends boundary condition. The combined effect of casing weight and axial tension on casing deflection is analyzed in detail.
Scalable algorithms for adaptive statistical designs

We present a scalable, high-performance solution to multidimensional recurrences that arise in adaptive statistical designs. Adaptive designs are an important class of learning algorithms for a stochastic environment, and we focus on the problem of optimally assigning patients to treatments in clinical trials. While adaptive designs have significant ethical and cost advantages, they are rarely utilized because of the complexity of optimizing and analyzing them. Computational challenges include massive memory requirements, few calculations per memory access, and multiply-nested loops with dynamic indices. We analyze the effects of various parallelization options, and while standard approaches do not work well, with effort an efficient, highly scalable program can be developed. This allows us to solve problems thousands of times more complex than those solved previously, which helps make adaptive designs practical. Further, our work applies to many other problems involving neighbor recurrences, such as generalized string matching.
The purinosome, a multi-protein complex involved in the de novo biosynthesis of purines in humans

Purine nucleotides are ubiquitous molecules that play vital roles in all kingdoms of life, not only as components of nucleic acids, but also participating in signaling and energy storage. Cellular pools of purines are maintained by the tight control of several complementary and sometimes competing processes including de novo biosynthesis, salvage and catabolism of nucleotides. While great strides have been made over the past sixty years in understanding the biosynthesis of purines, we are experiencing a renaissance in this field. In this feature article we discuss the most recent discoveries relating to purine biosynthesis, with particular emphasis upon the dynamic multi-protein complex called the purinosome. In particular we highlight advances made towards understanding the assembly, control and function of this protein complex and the attempts made to exploit this knowledge for drug discovery.
Hydroacylation of 2-vinyl benzaldehyde systems: an efficient method for the synthesis of chiral 3-substituted indanones.

Asymmetric rhodium-catalyzed hydroacylation has been utilized in the synthesis of 3-substituted indanones with high conversions and enantioselectivity. The hydroacylation reaction of 2-vinyl benzaldehyde had been previously reported to give a low yield of indanone and an unidentified product. We have identified this compound as a dimer of the starting material. Substitution at the α-position of the 2-vinyl benzaldehyde substrates blocks the competitive dimerization reaction and allows the reaction to proceed with yields generally greater than 90%. Utilization of BINAP as a chiral ligand results in good chemical yields and enantioselectivity greater than 95% in most cases.
Is late- life caloric restriction beneficial?

Caloric restriction initiated in young mice and rats results in increases in mean and median life span. When caloric restriction is implemented in older animals, an increase in life span is still observed; however, the magnitude of the increase is not as great as that observed in animals calorie restricted since they were young. Here we report the results of a pilot study in which caloric restriction was initiated in mature, older rats. Survival rates and terminal pathology were characterized and compared between a cohort of 17 continually ad libitum fed Long Evans rats and a cohort of 18 Long Evans rats, which were gradually introduced to 33% restriction in diet consumption at 18 months of age. No difference in the median life span was observed between the two groups. The data suggest there may be a level of maturity, or a stage in the aging process, after which caloric restriction no longer increases longevity.
Efficiently supporting order in XML query processing

XML is an ordered data model and XQuery expressions return results that have a well-defined order. However, little work on how order is supported in XML query processing has been done to date. In this paper we study the issues related to handling order in the XML context, namely challenges imposed by the XML data model, the variety of order requirements of the XQuery language, and the need to maintain order in the presence of updates to the XML data. We propose an efficient solution that addresses all these issues. Our solution is based on a key encoding for XML nodes that serves as node identity and at the same time encodes order. We design rules for encoding order of processed XML nodes based on the XML algebraic query execution model and the node key encoding. These rules do not require any actual sorting for intermediate results during execution. Our approach enables efficient order-sensitive incremental view maintenance as it makes most XML algebra operators distributive with respect to bag union. We prove the correctness of our order encoding approach. Our approach is implemented and integrated with Rainbow, an XML data management system developed at WPI. We have tested the efficiency of our approach using queries that have different order requirements. We have also measured the relative cost of different components related to our order solution in different types of queries. In general the overhead of maintaining order in our approach is very small relative to the query processing time.
Generation and reactivity of singlet oxygen within zeolites:remarkable control of hydroperoxidation of alkenes

A highly selective oxidation of alkenes included within a Y zeolite is achieved by generating singlet oxygen via excitation of a monomeric dye exchanged within a zeolite; conformational control brought forth by the medium is suggested to be responsible for the observed remarkable selectivity.
Effect of periodic shear on avalanches in granular systems

Abstract Surface flow down a granular pile (“avalanches”) can be excited by shear forces or by vibration. Based on a generalization of a recently proposed minimal dynamical mean field model, we discuss theoretically how a periodically modulated shear rate about a zero mean can change the dynamics of avalanches. In particular, we report the unexpected effect of non-periodic avalanching due to periodic driving. The predicted effects should be experimentally observable in two-dimensional drums by modulating the rotation rate.
Understanding the Slowing Growth Rate of the People's Republic of China

It is increasingly accepted that the gross domestic product (GDP) growth rate of the People's Republic of China (PRC) is slowing down, but the reasons for the slowdown are not yet well understood. ...
Algebraic Frobenius splitting of cotangent bundles of flag varieties

Abstract Following the program of algebraic Frobenius splitting begun by Kumar and Littelmann, we use representation-theoretic techniques to construct a Frobenius splitting of the cotangent bundle of the flag variety of a semisimple algebraic group over an algebraically closed field of positive characteristic. We also show that this splitting is the same as one of the splittings constructed by Kumar, Lauritzen, and Thomsen.
Subdominant Matroid Ultrametrics

Given a matroid M on the ground set E, the Bergman fan e B(M), or space of M- ultrametrics, is a polyhedral complex in R E which arises in several different areas, such as tropical algebraic geometry, dynamical systems, and phylogenetics. Motivated by the phylogenetic situ- ation, we study the following problem: Given a point ω in R E , we wish to nd an M-ultrametric which is closest to it in the '¥-metric. The solution to this problem follows easily from the existence of the subdominant M-ultramet- ric: a componentwise maximum M-ultrametric which is componentwise smaller than ω. A pro- cedure for computing it is given, which brings together the points of view of matroid theory and tropical geometry. When the matroid in question is the graphical matroid of the complete graph Kn, the Bergman fan e B(Kn) parameterizes the equidistant phylogenetic trees with n leaves. In this case, our results provide a conceptual explanation for Chepoi and Fichet's method for computing the tree that most closely matches measured data.
Interaction of Rydberg atoms with a metal surface in the presence of an external electric field

The behavior of Rydberg atoms near metal surfaces in the presence of an external electric field has been examined theoretically to evaluate their potential use as an experimental probe of electron tunneling processes at surfaces. These ab initio calculations reveal strong hybridization that leads to a shift and broadening of the Rydberg levels that depend sensitively on the atom-surface separation and the strength of the applied electric field. A range of external fields exists, however, for which the Rydberg atoms ionize at sufficiently large atom-surface separations that, even in the presence of image charge attraction, the resulting positive ions can escape the surface and provide an experimentally observable signal. \textcopyright{} 1996 The American Physical Society.
A model for predicting magnetic particle capture in a microfluidic bioseparator

A model is presented for predicting the capture of magnetic micro/nano-particles in a bioseparation microsystem. This bioseparator consists of an array of conductive elements embedded beneath a rectangular microfluidic channel. The magnetic particles are introduced into the microchannel in solution, and are attracted and held by the magnetic force produced by the energized elements. Analytical expressions are obtained for the dominant magnetic and fluidic forces on the particles as they move through the microchannel. These expressions are included in the equations of motion, which are solved numerically to predict particle trajectories and capture time. This model is well-suited for parametric analysis of particle capture taking into account variations in particle size, material properties, applied current, microchannel dimensions, fluid properties, and flow velocity.
Investigating Human Factors in Image Forgery Detection

In today's age of internet and social media, one can find an enormous volume of forged images on-line. These images have been used in the past to convey falsified information and achieve harmful intentions. The spread and the effect of the social media only makes this problem more severe. While creating forged images has become easier due to software advancements, there is no automated algorithm which can reliably detect forgery.Image forgery detection can be seen as a subset of image understanding problem. Human performance is still the gold-standard for these type of problems when compared to existing state-of-art automated algorithms. We conduct a subjective evaluation test with the aid of eye-tracker to investigate into human factors associated with this problem. We compare the performance of an automated algorithm and humans for forgery detection problem. We also develop an algorithm which uses the data from the evaluation test to predict the difficulty-level of an image. The experimental results presented in this paper should facilitate development of better algorithms in the future.
Low-momentum interactions for nuclei

We show how the renormalization group is used to construct a low-momentum nucleon-nucleon interaction V low k , which unifies all potential models used in nuclear structure calculations. V low k can be directly applied to the nuclear shell model or to nucleonic matter without a G matrix resummation. It is argued that V low k parametrizes a high-order chiral effective field theory two-nucleon force. We use cutoff dependence as a tool to assess the error in the truncation of nuclear forces to two-nucleon interactions and introduce a low-momentum three-nucleon force, which regulates A = 3, 4 binding energies. The adjusted three-nucleon interaction is perturbative for small cutoffs. In contrast to other precision interactions, the error due to missing many-body forces can be estimated, when V low k and the corresponding three-nucleon force are used in nuclear structure calculations and the cutoff is varied.
Optimal asset taxes in financial markets with aggregate uncertainty

This paper studies Pareto-optimal risk-sharing arrangements in a private information economy with aggregate uncertainty and ex ante heterogeneous agents. I show how to implement Pareto optima as equilibria when agents can trade claims to consumption contingent on aggregate shocks in financial markets. The first result is that if aggregate and idiosyncratic shocks are independent, the implementation of optimal allocations does not require any interventions in financial markets. This result can be extended to dynamic settings in the sense that, in this case, only savings need to be distorted, but not trades in financial markets. Second, I characterize optimal trading distortions in financial markets when aggregate and idiosyncratic shocks are not independent. In this case, optimal asset taxes must be higher for those securities that pay out in aggregate states in which consumption is more volatile. For instance, this can provide an efficiency justification for the frequently observed differential tax treatment of different asset classes, such as debt and equity claims.
Induction-linac based free electron laser amplifier for fusion applications☆

Abstract We describe an induction-linac based free electron laser amplifier design for producing multi-megawatt levels of microwave power for electron cyclotron resonance heating of tokamak fusion devices such as the Compact Ignition Tokamak or the International Thermonuclear Experimental Reactor. The wiggler design strategy incorporates a tapering algorithm suitable for FEL systems with moderate space charge effects and minimizes spontaneous noise growth at frequencies below the fundamental, while enhancing the growth of the signal at the fundamental. In addition, engineering design considerations of the waveguide wall loading and electron beam fill factor in the waveguide set limits on the waveguide dimensions, the wiggler magnet gap spacing, the wiggler period, and the minimum magnetic field strength in the tapered region of the wiggler. This FEL is designed to produce an average power of about 10 MW at frequencies in the range from 280 to 560 GHz. The achievement of this average power at a reasonable cost requires a high duty factor, which affects some component design. In addition, the desire to obtain a high extraction efficiency pushes the beam energy up and requires magnetic field strengths in the wiggler that are near or possibly larger than the Halbach limit. We used a methodology for our system study that had been developed earlier. We considered several FEL configurations and selected one that minimized total cost. We determined that increasing the beam energy requires that the wiggler use vanadium-permendur as the pole material. We discuss the basic design of the selected configuration and give the expected performance.
Three-Dimensional Numerical Simulation of the Jet Screech Phenomenon

Three-dimensional numerical simulations of the jet screech phenomenon are carried out using the multiple-size-mesh, multiple-time-step, dispersion-relation-preserving scheme. The simulations reproduce all of the experimentally observed characteristic features of the screech tones, including the axisymmetric A 1 and A 2 modes, the flapping/helical B and C modes, and the staging phenomenon. Screech tone frequencies as well as intensities calculated by the numerical simulations are in excellent agreement with experimental measurements. Power spectral analysis of the numerical simulation data provides irrefutable evidence that, whenever two tones are measured in the noise spectrum, it is not because there is a continuous switching from one tone to another, but because the two tones actually coexist simultaneously. A first explanation of why there are two axisymmetric and two flapping/helical screech modes based on two feedback mechanisms is offered. Strong evidence is provided to support the proposed mechanisms.
From the Periphery to the Center? The Evolving WTO Jurisprudence on Transparency and Good Governance

The rise of the regulatory state in the latter half of the 20th century is reflected in the text of the World Trade Organization (WTO) Agreements and specifically its transparency related obligations. The oldest transparency and good governance obligation of the WTO is Article X of General Agreement on Tariffs and Trade (GATT). Article X imposes broad publication and due process requirements on the administration of measures in the area of trade in goods. The language of Article X is duplicated or incorporated by reference throughout the WTO Agreements. During the GATT years (1947-94), Article X was a silent provision dismissed by GATT panels as ‘subsidiary’ to the other ‘substantive’ provisions of the GATT. Since the creation of the WTO, Article X has emerged from obscurity, and is now viewed as creating obligations of ‘fundamental importance,’ such as transparency and due process. In addition, there has been an exponential increase in the number of cases asserting Article X claims before WTO panels and the Appellate Body. The resulting treatment of such claims by the WTO dispute settlement bodies reflects both the emerging role of the WTO as a supranational administrative body and the continuing discomfort of panels and the Appellate Body with applying good governance obligations.