cssi/SciSciGPT-SciSciNet huggingface dataset:
Numerical analysis of a NACA0012 airfoil with leading edge ice accretions

Analysis of a NACA0012 airfoil with leading edge ice has been performed using a Navier-Stokes code coupled with a grid generation code. The computed results were compared to experimental information obtained for an airfoil with a well defined artificial ice shape. The computations were performed at angles of attack ranging from zero to ten degrees. This range is sufficient to show the development of the separation bubble aft of the ice shape on both the upper and lower surfaces. Velocity profile plots in the separation bubble are examined in order to determine if recirculation patterns are predicted properly and if separation and reattachment points are found within the resolution of the experimental information. Also, the massive separation near the point of stall is examined in order to more accurately evaluate the lift coefficient curve in that region. Lift, drag, and moment coefficients are computed and compared to experiment.
Amine-catalyzed direct Diels–Alder reactions of α,β-unsaturated ketones with nitro olefins

Amine-catalyzed Diels–Alder reactions of α,β-unsaturated ketones with dienophiles have been developed. Either (S)-1-(2-pyrrolidinylmethyl)pyrrolidine or l-proline catalyzed the in situ-generation and reaction of 2-amino-1,3-dienes to provide cyclohexanone derivatives in good yield (up to 87%) in one step with modest enantioselectivity.
RECENT PROGRESS IN THE SYNTHESIS OF ARTEMISININ AND ITS DERIVATIVES

(2006). RECENT PROGRESS IN THE SYNTHESIS OF ARTEMISININ AND ITS DERIVATIVES. Organic Preparations and Procedures International: Vol. 38, No. 1, pp. 1-80.
Irradiation damage of single crystal, coarse-grained, and nanograined copper under helium bombardment at 450 °C

The irradiation damage behaviors of single crystal (SC), coarse-grained (CG), and nanograined (NG) copper (Cu) films were investigated under Helium (He) ion implantation at 450 °C with different ion fluences. In irradiated SC films, plenty of cavities are nucleated, and some of them preferentially formed on growth defects or dislocation lines. In the irradiated CG Cu, cavities formed both in grain interior and along grain boundaries; obvious void-denuded zones can be identified near grain boundaries. In contrast, irradiation-induced cavities in NG Cu were observed mainly gathering along grain boundaries with much less cavities in the grain interiors. The grains in irradiated NG Cu are significantly coarsened. The number density and average radius of cavities in NG Cu was smaller than that in irradiated SC Cu and CG Cu. These experiments indicate that grain boundaries are efficient sinks for irradiation-induced vacancies and highlight the important role of reducing grain size in suppressing radiation-induced void swelling.
Managing Firm Resources in Dynamic Environments to Create Value: Looking Inside the Black Box

We address current criticisms of the RBV (oversight of dynamism, environmental contingencies, and managers' role) by linking value creation in dynamic environmental contexts to the management of firm resources. Components of the resource management model include structuring the resource portfolio; bundling resources to build capabilities; and leveraging capabilities to provide value to customers, gain a competitive advantage, and create wealth for owners. Propositions linking resource management and value creation are offered to shape future research.
A priori wirelength and interconnect estimation based on circuit characteristics

Interconnect prediction is very important for early feasibility studies in modern design flows. Most of the current interconnect estimation techniques estimate either the average or the total wirelength and some qualitative measure of routing demand for circuits. A priori techniques estimate these parameters without actually performing circuit placement. We propose a new a priori interconnect and wirelength estimation methodology for island style field programmable gate arrays (FPGAs). For a given design, we estimate bounding box semiperimeter wirelengths of all nets for an optimized placement and the minimum number of tracks per channel required for successful routing on an FPGA device. We analyze the structural characteristics of circuits and limitations posed by the FPGA architecture to derive a consistent model for wirelength and routing demand estimation. We identify reconvergences present in a circuit as an important global circuit characteristic in wirelength prediction. Our overall results show that we have an average error of 11.6% w.r.t. semiperimeter wirelength measured from the optimized layout using VPR. Also, the number of routing tracks per channel is predicted with an average error of 13.2% of the detailed routing results from VPR.
Giving According to GARP: An Experimental Test of the Consistency of Preferences for Altruism

Subjects in economic laboratory experiments have clearly expressed an interest in behaving unselfishly. They cooperate in prisoners’ dilemma games, they give to public goods, and they leave money on the table when bargaining. While some are tempted to call this behavior irrational, economists should ask if this unselfish and altruistic behavior is indeed self-interested. That is, can subjects’ concerns for altruism or fairness be expressed in the economists’ language of a well-behaved preference ordering? If so, then behavior is consistent and meets our definition of rationality. This paper explores this question by applying the axioms of revealed preference to the altruistic actions of subjects. If subjects adhere to these axioms, such as GARP, then we can infer that a continuous, convex, and monotonic utility function could have generated their choices. This means that an economic model is sufficient to understand the data and that, in fact, altruism is rational. We do this by offering subjects several opportunities to share a surplus with another anonymous subject. However, the costs of sharing and the surplus available vary across decisions. This price and income variation creates budgets for altruistic activity that allow us to test for an underlying preference ordering. We found that subjects exhibit a significant degree of rationally altruistic behavior. Over 98% of our subjects made choices that are consistent with utility maximization. Only a quarter of subjects are selfish money-maximizers, and the rest show varying degrees of altruism. Perhaps most strikingly, almost half of the subjects exhibited behavior that is exactly consistent with one of three standard CES utility functions: perfectly selfish, perfect substitutes, or Leontief. Those with Leontief preferences are always dividing the surplus equally, while those with perfect substitutes preferences give everything away when the price of giving is less than one, but keep everything when the price of giving is greater than one. Using the data on choices, we estimated a population of utility functions and applied these to predict the results of other studies. We found that our results could successfully characterize the outcomes of other studies, indicating still further that altruism can be captured in an economic model.
General self-dual Yang-Mills solutions

The recent work of Atiyah, Hitchin, Drinfeld, and Manin is used to discuss self-dual Yang-Mills solutions for the compact gauge groups $O(n)$, $\mathrm{SU}(n)$, and $\mathrm{Sp}(n)$. It is shown that the resulting solutions contain the correct number of parameters for all values of the topological charge. Although explicit construction of a general self-dual field requires the solution of a finite-dimensional, nonlinear matrix equation, we show that for widely separated instantons this equation can be solved perturbatively, providing a systematic expansion about the dilute-gas limit and a physical interpretation of the independent parameters in this limit. Further, closed-form expressions can be obtained for the general SU(2) solutions with topological charge 2 or 3. Finally, explicit isospin-1/2 and isospin-1 propagators are derived for a massless scalar field in the presence of the general self-dual SU(2) solution.
Robustness analysis of a class of discrete-time recurrent neural networks under perturbations

A robustness analysis is conducted for a large class of discrete-time recurrent neural networks for associative memories under perturbations of system parameters. The present paper aims to give an answer to the following question. Given a discrete-time neural network with specified stable memories (specified asymptotically stable equilibria), under what conditions will a perturbed model of the discrete-time neural network possess stable memories that are close (in distance) to the stable memories of the unperturbed discrete-time neural network model? Robustness stability results for perturbed discrete-time neural network models are established and conditions are obtained for the existence of asymptotically stable equilibria of the perturbed discrete-time neural network models which are near the asymptotically stable equilibria of the original unperturbed neural networks. In the present results, quantitative estimates (explicit estimates of bounds) are given for the distance between the corresponding equilibrium points of the unperturbed and perturbed discrete-time neural network models considered herein.
An adaptive analog continuous-time CMOS biquadratic filter

An adaptive analog continuous-time biquadratic filter is realized in a 2- mu m digital CMOS process for operation at 300 kHz. The biquad implements the notch, bandpass and low-pass transfer functions. The only parameter adapted is the resonant frequency of the biquad, which is identical to the notch frequency and the bandpass center frequency. The update method is based on a least-means-square algorithm which adapts the notch frequency to minimize the power at the notch filter output. The actual update is modified to reduce the circuit complexity to one biquad and one correlator. When the filter is tracking a sinusoid, this update generates a ripple-free gradient that decreases tracking error. Applications include phase-frequency detectors, FM demodulators (linear and frequency shift keying), clock extractors, and frequency acquisition aids for phase-locked loops and Costas loops. Measured results from experimental prototypes are presented. Nonidealities of an all-analog implementation are discussed, along with suggestions to improve performance. >
Some observations on the pyrolysis of methyllithium

Abstract To obtain a more detailed understanding of the synthesis of dilithiomethane by pyrolysis of methyllithium, we have studied this reaction in detail with mixtures of labeled methyllithium precursors. We have also made a detailed study of the gaseous products of the pyrolysis which include several hydrocarbons in addition to methane. This information may be important in establishing a mechanism for the pyrolysis of methyllithium.
Photochemical properties of tin(IV) phthalocyanines: a comparison between the dichloro and superphthalocyanines

Abstract The photochemical behavior of Tin(IV) dichlorophthalocyaninate, Sn(pc)Cl 2 , and tin(IV) super phthalocyanine, Sn(pc) 2 , has been investigated by flash photolysis. Irradiations, λ exc ∼ 640 nm, of Sn(pc)Cl 2 generate the lowest lying triplet state, ( 3 ππ * )Sn(pc)Cl 2 , with a half lifetime, τ ∼ 40 μ s . Quenching of this excited state with paradinitrobenzene produces a Sn(IV) phthalocyanine radical which isomerizes to a Sn(III) complex in a μ s time domain. The photochemistry of Sn(pc) 2 can be described in terms of an unreactive 3 ππ * and a reactive CT excited state. Dissociation reactions form Sn II (pc) and Sn IV (pc)(solvent) 2 . The regeneration of the superphthalocyanine takes place through a Sn(III) intermediate.
INTERPRETABLE ASSET MARKETS

Abstract In this paper we show that measures of economic uncertainty (conditional volatility of consumption) predict and are predicted by valuation ratios at long horizons. Further we document that asset valuations drop as economic uncertainty rises—that is, financial markets dislike economic uncertainty. Moreover, future earnings growth rates are sharply predicted by current price–earnings ratios. It seems that much of the variation in asset prices can be attributed to fluctuations in economic uncertainty and expected cash-flow growth. This empirical evidence is consistent with the implications of existing parametric general equilibrium models. Hence, the channels of fluctuating economic uncertainty and expected growth seem important for interpreting asset markets.
Angular Momentum Evolution of Stars in the Orion Nebula Cluster

We present theoretical models of stellar angular momentum evolution from the Orion Nebula Cluster (ONC) to the Pleiades and the Hyades. We demonstrate that observations of the Pleiades and Hyades place tight constraints on the angular momentum loss rate from stellar winds. The observed periods, masses, and ages of ONC stars in the range 0.2-0.5 M☉ and the loss properties inferred from the Pleiades and Hyades stars are then used to test the initial conditions for stellar evolution models. We use these models to estimate the distribution of rotational velocities for the ONC stars at the age of the Pleiades (120 Myr). The modeled ONC and observed Pleiades distributions of rotation rates are not consistent if only stellar winds are included. In order to reconcile the observed loss of angular momentum between these two clusters, an extrinsic loss mechanism, such as protostar-accretion disk interaction, is required. Our model, which evolves the ONC stars with a mass-dependent saturation threshold, normalized such that ωcrit = 5.4 ω☉ at 0.5 M☉, and includes a distribution of disk lifetimes that is uniform over the range 0-6 Myr, is consistent with the Pleiades data. This model for disk-locking lifetimes is also consistent with disk lifetimes inferred from the percentage of stars with infrared excesses observed in young clusters. Different models, using a variety of initial period distributions and different maximum disk lifetimes, are also compared with the Pleiades. For disk-locking models that use the ONC period distribution and a uniform distribution of disk lifetimes over the range 0 to τmax, the acceptable range of the maximum lifetime is 3.5 Myr < τmax < 8.5 Myr. We compare these results with birth line models that use different starting period distributions.
Carrier heating and negative photoconductivity in graphene

We investigated negative photoconductivity in graphene using ultrafast terahertz techniques. Infrared transmission was used to determine the Fermi energy, carrier density, and mobility of p-type chemical vapor deposition graphene samples. Time-resolved terahertz photoconductivity measurements using a tunable mid-infrared pump probed these samples at photon energies between 0.35 eV and 1.55 eV, approximately one-half to three times the Fermi energy of the samples. Although interband optical transitions in graphene are blocked for pump photon energies less than twice the Fermi energy, we observe negative photoconductivity at all pump photon energies investigated, indicating that interband excitation is not required to observe this effect. Our results are consistent with a thermalized free-carrier population that cools by electron-phonon scattering, but are inconsistent with models of negative photoconductivity based on population inversion.
Advancement-onlay: an improved technique of fronto-orbital remodeling in craniosynostosis.

Eighteen patients with nonsyndromic craniosynostosis underwent fronto-orbital remodeling with an advancement-onlay technique. The mean age of the infants was 5 months (range = 2-11 months) when the procedure was performed for the following indications: unilateral coronal synostosis (n = 10); bilateral coronal synostosis (n = 3); metopic synostosis (n = 2); and multiple craniosynostoses (n = 3). The technique consists of (1) unilateral or bifrontal craniotomy, (2) superior orbital rim recontouring and advancement, and (3) frontal bone graft rotation and onlay. Posteriorly, the frontal bone graft is left "floating," while anteriorly, rigid fixation with microplates and screws has supplanted wire osteosynthesis. The use of rigid fixation prevents uncontrolled "float" of the forehead and eliminates the need for temporal struts. Follow-up time ranged from 6 to 60 months (mean = 2.6 years). There were no serious postoperative complications. Surgical results were good to excellent in 94% of cases and poor to fair in 6%. Only 1 patient with a Kleeblattschadel deformity required major revision, while another patient with trigonocephaly underwent a minor, extracranial recontouring procedure. Supraorbital rim and/or forehead recession suggestive of relapse or initial inadequacy of anterior projection occurred in 3 patients (17%). Residual, mild contour abnormalities of the forehead and/or temporal regions were found in 5 cases. To date, no gross disturbances in craniofacial growth related to our method of rigid fixation have been observed and no clinically detectable resynostosis has occurred.
Distributed Opportunistic Scheduling for MIMO Ad-Hoc Networks

Distributed opportunistic scheduling (DOS) protocols are proposed for multiple-input multiple-output (MIMO) ad-hoc networks with contention-based medium access. The proposed scheduling protocols distinguish themselves from other existing works by their explicit design for system throughput improvement through exploiting spatial multiplexing and diversity in a distributed manner. As a result, multiple links can be scheduled to simultaneously transmit over the spatial channels formed by transmit/receiver antennas. Taking into account the tradeoff between feedback requirements and system throughput, we propose and compare protocols with different levels of feedback information. Furthermore, in contrast to the conventional random access protocols that ignore the physical channel conditions of contending links, the proposed protocols implement a pure threshold policy derived from optimal stopping theory, i.e. only links with threshold-exceeding channel conditions are allowed for data transmission. Simulation results confirm that the proposed protocols can achieve impressive throughput performance by exploiting spatial multiplexing and diversity.
Monte Carlo simulations of H2 formation on stochastically heated grains

Continuous-time, random-walk Monte Carlo simulations of H2 formation on grains have been performed for surfaces that are stochastically heated by photons. We have assumed diffuse cloud conditions and used a variety of grains of varying roughness and size based on olivine. The simulations were performed at different optical depths. We confirmed that small grains (r≤ 0.02 μm) have low modal temperatures with strong fluctuations, which have a large effect on the efficiency of the formation of molecular hydrogen. The grain size distribution highly favours small grains and therefore H2 formation on these particles makes a large contribution to the overall formation rate for all but the roughest surfaces. We find that at AV= 0 only the roughest surfaces can produce the required amount of molecular hydrogen, but by AV= 1, smoother surfaces are possible alternatives. Use of a larger value for the evaporation energy of atomic hydrogen, but one still consistent with experiment, allows smoother surfaces to produce more H2.
Integrating Scaffolding Experiences for the Youngest Visitors in Museums

AbstractResearch demonstrates that children have vast potential to expand their knowledge base with simple supports from adults and older children. Children's museums have a heightened awareness of the value in and the need to reach out to support adults accompanying children, thus bringing about an emphasis on family learning. Iterative exhibition studies conducted at The Children's Museum of Indianapolis illustrate the impact of planning for family learning. But for any museum, intentionally applying the strategy of scaffolding by building on simple concepts and working toward mastery of ideas, can inform adults and simultaneously help children stretch to new levels of understanding and achievement. This strategy requires curators, educators and exhibit developers to work collaboratively to determine various levels of accessibility of content and activity moving from entry level ideas through more complex and abstract ones for older children and adults. Children visiting museums of all types is certainl...
Molecular origin and functional consequences of digital signaling and hysteresis during Ras activation in lymphocytes.

Activation of Ras proteins underlies functional decisions in diverse cell types. Two molecules, Ras-GRP and SOS (Ras–guanine nucleotide–releasing protein and Son of Sevenless, respectively), catalyze Ras activation in lymphocytes. Binding of active Ras to the allosteric pocket of SOS markedly increases the activity of SOS. Thus, there is a positive feedback loop regulating SOS. Combining in silico and in vitro studies, we demonstrate that “digital” signaling in lymphocytes (cells are “on” or “off”) is predicated on this allosteric regulation of SOS. The SOS feedback loop leads to hysteresis in the dose-response curve, which may enable T cells to exhibit “memory” of past encounters with antigen. Ras activation by Ras-GRP alone is “analog” (a graded increase in activation in response to an increase in the amplitude of the stimulus). We describe how the complementary analog (Ras-GRP) and digital (SOS) pathways act on Ras to efficiently convert analog input to digital output and make predictions regarding the importance of digital signaling in lymphocyte function and development.
Two particle azimuthal correlation measurements in PHENIX

Abstract Two particle azimuthal correlation functions are presented for charged hadrons produced in Au + Au collisions at RHIC ( S N N = 200 GeV). The correlation functions indicate sizeable asymmetries and anisotropies. The trend of the asymmetries is compatible with the presence of emission patterns associated with mini-jets. The magnitude and the trend of the differential anisotropies v2(pT) and v2(NPart), provide important model constraints.
Hybrid concatenated codes and iterative decoding

A hybrid concatenated code is a combination of parallel and serial concatenated codes. Here we consider an example with three codes and two interleavers. An upper bound to the bit error rate (BER) of the hybrid code is obtained. Design rules for the three component codes that maximize the interleavers gain and the asymptotic slope of the BER curves are discussed. A low-complexity iterative decoding algorithm with near maximum-likelihood performance is proposed. Comparisons with "turbo codes" and with serially concatenated codes show that the hybrid scheme offers better performance at very low BER.
On empty convex polygons in a planar point set

Let P be a set of n points in general position in the plane. Let Xk(P) denote the number of empty convex k-gons determined by P. We derive, using elementary proof techniques, several equalities and inequalities involving the quantities Xk(P) and several related quantities. Most of these equalities and inequalities are new, except for a few that have been proved earlier using a considerably more complex machinery from matroid and polytope theory, and algebraic topology. Some of these relationships are also extended to higher dimensions. We present several implications of these relationships, and discuss their connection with several long-standing open problems, the most notorious of which is the existence of an empty convex hexagon in any point set with sufficiently many points.
On the numerical evaluation of loop integrals with Mellin-Barnes representations

An improved method is presented for the numerical evaluation of multi-loop integrals in dimensional regularization. The technique is based on Mellin-Barnes representations, which have been used earlier to develop algorithms for the extraction of ultraviolet and infrared divergencies. The coefficients of these singularities and the non-singular part can be integrated numerically. However, the numerical integration often does not converge for diagrams with massive propagators and physical branch cuts. In this work, several steps are proposed which substantially improve the behavior of the numerical integrals. The efficacy of the method is demonstrated by calculating several two-loop examples, some of which have not been known before.
Active Stabilization of Centrifugal Compressor Surge

Active suppression of centrifugal compressor surge has been demonstrated on a centrifugal compressor equipped with a servo-actuated plenum exit throttle controller. The control scheme is fundamentally different from conventional surge control techniques in that it addresses directly the dynamic behavior of the compression system to displace the surge line to lower mass flows. The method used is to feed back perturbations in plenum pressure rise, in real time, to a fast-acting control valve. The increased aerodynamic damping of incipient oscillations due to the resulting valve motion allows stable operation past the normal surge line. For the compressor used, a 25 percent reduction in the surge point mass flow was achieved over a range of speeds and pressure ratios. Time-resolved measurements during controlled operation revealed that the throttle required relatively little power to suppress the surge oscillations, because the disturbances are attacked in their initial stages. Although designed for operation with small disturbances, the controller was also able to eliminate existing, large-amplitude, surge oscillations. Comparison of experimental results with theoretical predictions showed that a lumped parameter model appeared adequate to represent the behavior of the compression system with the throttle controller and, perhaps more importantly, to be used in the design of more sophisticated control strategies.
Packing and Covering Properties of Subspace Codes for Error Control in Random Linear Network Coding

Codes in the projective space and codes in the Grassmannian over a finite field-referred to as subspace codes and constant-dimension codes (CDCs), respectively-have been proposed for error control in random linear network coding. For subspace codes and CDCs, a subspace metric was introduced to correct both errors and erasures, and an injection metric was proposed to correct adversarial errors. In this paper, we investigate the packing and covering properties of subspace codes with both metrics. We first determine some fundamental geometric properties of the projective space with both metrics. Using these properties, we then derive bounds on the cardinalities of packing and covering subspace codes, and determine the asymptotic rates of optimal packing and optimal covering subspace codes with both metrics. Our results not only provide guiding principles for the code design for error control in random linear network coding, but also illustrate the difference between the two metrics from a geometric perspective. In particular, our results show that optimal packing CDCs are optimal packing subspace codes up to a scalar for both metrics if and only if their dimension is half of their length (up to rounding). In this case, CDCs suffer from only limited rate loss as opposed to subspace codes with the same minimum distance. We also show that optimal covering CDCs can be used to construct asymptotically optimal covering subspace codes with the injection metric only.
Development of a failure locus for a 3-dimensional anterior crutiate ligament: A finite element analysis

This study investigates the combinations of loading which cause injury to knee joint ligaments. A 3D model of a knee, including bones, cartilage, menisci and ligament bundles was created from magnetic resonance images (MRI). Material properties for bone, cartilage, meniscus and ligament were all determined based on previous published work. The model incorporates a novel approach for accounting for prestrain in ligament bundles. The ligament bundle structures were resized based to their zero load lengths and strained to their reference lengths at full extension using FEBio (University of Utah). Previous studies investigating ligament failure used 1D nonlinear spring elements for ligament structures. The 3D ligament model will provide improved accuracy for locating bundle ruptures. By monitoring stresses and strains in ligament bundles during knee joint orientation simulations, ruptures can be virtually diagnosed. The results of these simulations can be used in clinical applications. In sports where anterior cruciate ligament (ACL) injuries are prevalent, training programs can be adapted to address the avoidance of harmful knee orientations. The ability to monitor where bundle ruptures occur will provide increased insight for practitioners in identifying more precise mechanisms of injury to ligaments and cartilage within the knee joint.
Performance Analysis for Sparse Support Recovery

The performance of estimating the common support for jointly sparse signals based on their projections onto lower-dimensional space is analyzed. Support recovery is formulated as a multiple-hypothesis testing problem. Both upper and lower bounds on the probability of error are derived for general measurement matrices, by using the Chernoff bound and Fano's inequality, respectively. The upper bound shows that the performance is determined by a quantity measuring the measurement matrix incoherence, while the lower bound reveals the importance of the total measurement gain. The lower bound is applied to derive the minimal number of samples needed for accurate direction-of-arrival (DOA) estimation for a sparse representation based algorithm. When applied to Gaussian measurement ensembles, these bounds give necessary and sufficient conditions for a vanishing probability of error for majority realizations of the measurement matrix. Our results offer surprising insights into sparse signal recovery. For example, as far as support recovery is concerned, the well-known bound in Compressive Sensing with the Gaussian measurement matrix is generally not sufficient unless the noise level is low. Our study provides an alternative performance measure, one that is natural and important in practice, for signal recovery in Compressive Sensing and other application areas exploiting signal sparsity.
Plasmonic photothermal heating of intraperitoneal tumors through the use of an implanted near-infrared source

Plasmonic nanomaterials including gold nanorods are effective agents for inducing heating in tumors. Because near-infrared (NIR) light has traditionally been delivered using extracorporeal sources, most applications of plasmonic photothermal therapy have focused on isolated subcutaneous tumors. For more complex models of disease such as advanced ovarian cancer, one of the primary barriers to gold nanorod-based strategies is the adequate delivery of NIR light to tumors located at varying depths within the body. To address this limitation, a series of implanted NIR illumination sources are described for the specific heating of gold nanorod-containing tissues. Through computational modeling and ex vivo studies, a candidate device is identified and validated in a model of orthotopic ovarian cancer. As the therapeutic, imaging, and diagnostic applications of plasmonic nanomaterials progress, effective methods for NIR light delivery to challenging anatomical regions will complement ongoing efforts to advance pl...
Asymptotics of Carleman Polynomials for Level Curves of the Inverse of a Shifted Zhukovsky Transformation

This paper complements the recent investigation of [4] on the asymptotic behavior of polynomials orthogonal over the interior of an analytic Jordan curve $$L$$ . We study the specific case of $$L=\{z= w-1 +(w-1)^{-1},\ |w|=R\}$$ , for some $$R>2$$ , providing an example that exhibits the new features discovered in [4], and for which the asymptotic behavior of the orthogonal polynomials is established over the entire domain of orthogonality. Surprisingly, this variation of the classical example of the ellipse turns out to be quite sophisticated. After properly normalizing the corresponding orthonormal polynomials $$p_n, n=0,1,\ldots $$ , and on a critical subregion of the orthogonality domain, a subsequence $$\{p_{n_k}\}$$ converges if and only if $$\log _{\mu ^4}(n_k)$$ converges modulo 1 ( $$\mu $$ being an important quantity associated to $$L$$ ). As a consequence, the limiting points of the sequence $$\{p_n\}$$ form a one parameter family of functions, the range of the parameter being the interval $$[0,1)$$ . The polynomials $$p_n$$ are much influenced by a certain integrand function, the explained behavior being the result of this integrand having a nonisolated singularity that is a cluster point of poles. The nature of this singularity arises purely from geometric considerations, as opposed to the more common situation where the critical singularities come from the orthogonality weight.
Novel features of nitric oxide, endothelial nitric oxide synthase, and atherosclerosis

There is a complex pathophysiologic scenario involving nitric oxide (NO), endothelial nitric oxide synthase (eNOS), and the development of atherosclerosis and unstable atheroma. Endothelial damage induced by atherosclerosis leads to the reduction in bioactivity of ENOS with subsequent impaired release of NO. An important mechanism is local enhanced degradation of NO by increased generation of reactive oxygen species and other free radicals, with subsequent cascade of oxidation-sensitive mechanisms in the arterial wall. Novel molecular approaches have resulted in the development of new strains of mice lacking eNOS. These experimental models will help to understand how to implement NO-based therapies against atherosclerosis. L-arginine, the precursor of NO, has demonstrated beneficial effects in atherosclerosis and disturbed shear stress. The target or goal for new drugs should be the complete restoration of NO-mediated signaling pathways in atherosclerotic arteries.
An empirical study of smoothing techniques for language modeling

We survey the most widely-used algorithms for smoothing models for language n -gram modeling. We then present an extensive empirical comparison of several of these smoothing techniques, including those described by Jelinek and Mercer (1980); Katz (1987); Bell, Cleary and Witten (1990); Ney, Essen and Kneser (1994), and Kneser and Ney (1995). We investigate how factors such as training data size, training corpus (e.g. Brown vs. Wall Street Journal), count cutoffs, and n -gram order (bigram vs. trigram) affect the relative performance of these methods, which is measured through the cross-entropy of test data. We find that these factors can significantly affect the relative performance of models, with the most significant factor being training data size. Since no previous comparisons have examined these factors systematically, this is the first thorough characterization of the relative performance of various algorithms. In addition, we introduce methodologies for analyzing smoothing algorithm efficacy in detail, and using these techniques we motivate a novel variation of Kneser?Ney smoothing that consistently outperforms all other algorithms evaluated. Finally, results showing that improved language model smoothing leads to improved speech recognition performance are presented.
Dark energy in perturbative string cosmology

The apparent observation of dark energy poses problems for string the- ory. IndeSitterspace,orinquintessencemodels,onecannotdeneagauge-invariant S-matrix. Wearguethateternalquintessence doesnotariseinweaklycoupledstring theory, but pointout thatitisdicult todene anS-matrixeven inthepresence of perturbative potentials for the moduli. The solutions of the Fischler-Susskind equa- tions all have Big Bang or Big Crunch Singularities. We believe that an S-matrix (or S-vector) exists in this context but cannot be calculated by purely perturbative methods. Westudythepossibility ofmetastable deSittervacua insuchweakly cou- pled scenarios, and conclude that the S-matrix of the extreme weak coupling region cannot probe de Sitter physics. We also consider proposed explanations of the dark energy from the perspective of string theory, and nd that most are implausible. We note that it is possible that the axion constitutes both the dark matter and the dark energy.
Taking Stock of Work-Family Initiatives: How Announcements of "Family'Friendly" Human Resource Decisions Affect Shareholder Value

This study examines share price reactions to 231 work-family human resource policies adopted by Fortune 500 companies and announced in the Wall Street Journal between 1971 and 1996. Consistent with...
Junior Can't Borrow: A New Perspective on the Equity Premium Puzzle

Ongoing questions on the historical mean and standard deviation of the return on equities and bonds and on the equilibrium demand for these securities are addressed in the context of a stationary, overlapping-generations economy in which consumers are subject to a borrowing constraint. The key feature captured by the OLG economy is that the bulk of the future income of the young consumers is derived from their wages forthcoming in their middle age, while the bulk of the future income of the middle-aged consumers is derived from their savings in equity and bonds. The young would like to borrow and invest in equity but the borrowing constraint prevents them from doing so. The middle-aged choose to
Astrophysical explosions: from solar flares to cosmic gamma-ray bursts

Astrophysical explosions result from the release of magnetic, gravitational or thermonuclear energy on dynamical time scales, typically the sound-crossing time for the system. These explosions include solar and stellar flares, eruptive phenomena in accretion discs, thermonuclear combustion on the surfaces of white dwarfs and neutron stars, violent magnetic reconnection in neutron stars, thermonuclear and gravitational collapse supernovae and cosmic gamma-ray bursts, each representing a different type and amount of energy release. This paper summarizes the properties of these explosions and describes new research on thermonuclear explosions and explosions in extended circumstellar media. Parallels are drawn between studies of terrestrial and astrophysical explosions, especially the physics of the transition from deflagration-to-detonation.
Comparing directed efficiency of III-nitride nanowire light-emitting diodes

III-nitride-based nanowires are a promising platform for solid-state lighting. III-nitride nanowires that act as natural waveguides to enhance directed extraction have previously been shown to be free of extended defects even on foreign substrates, such as silicon. While the effi- ciency of nanowire-based light-emitting diodes (LEDs) has been investigated, there has yet to be a comparison of heterostructures based on nanowires grown in different crystallographic direc- tions.Wecomparedthe directed external quantum efficiency(EQE) ofIII-nitride LEDsonsilicon based on axial and radial nanowire heterostructures, considering m- and c-directional nanowires. The directed extraction efficiency was calculated using photonic simulations, and the internal quantum efficiency (IQE) was estimated using the A-B-C model. We found that m-directional axial heterostructures have the highest directed extraction efficiency, due to the strong polariza- tion anisotropy of III-nitrides, and display similar IQE as c-directional axial heterostructures. By combining IQE and directed extraction, a range of directed expected EQEs reveal that m-directional axial heterostructures have EQEs up to three times that of c-directional axial heterostructures, providing guidelines for the design of future nanowire-based LEDs. © 2014 Society of Photo-Optical Instrumentation Engineers (SPIE) (DOI: 10.1117/1.JNP.8.083095)
Cooperative Algorithms for MIMO Interference Channels

Interference alignment (IA) is a transmission technique for exploiting all available degrees of freedom in the frequency- or time-selective interference channel with an arbitrary number of users. Most prior work on IA, however, neglects interference from other nodes in the network that are not participating in the alignment operation. This paper proposes three generalizations of IA for the multiple-antenna interference channel with multiple users that account for colored noise, which models uncoordinated interference. First, a minimum interference-plus-noise leakage (INL) algorithm is presented and shown to be equivalent to previous subspace methods when noise is spatially white or negligible. This algorithm results in orthonormal precoders that are desirable for practical implementation with limited feedback. A joint minimum mean square error design that jointly optimizes the transmit precoders and receive spatial filters is then proposed, whereas previous designs neglect the receive spatial filter. Finally, a maximum signal-to-interference-plus-noise ratio (SINR) algorithm is developed and proven to converge, unlike previous maximum SINR algorithms. The sum throughput of these algorithms is simulated in the context of a network with uncoordinated cochannel interferers that are not participating in the alignment protocol. It is found that a network with cochannel interference can benefit from employing precoders that are designed to consider that interference, but in extreme cases, such as when only one receiver has a large amount of interference, ignoring that the cochannel interference is advantageous.
Unit Roots, TV-STARs, and the Commodity Terms of Trade: A Further Assessment of the Prebisch-Singer Hypothesis

This paper examines the Prebisch‐Singer hypothesis, that is, the hypothesis of a long-run decline in the prices of primary commodity prices relative to that of manufactured goods, by considering nonlinear alternatives. Specifically, in this paper we use bootstrap procedures to test the linear unit root model against models belonging to the family of smooth transition autoregressions (STARs) for 24 commodities, 1900‐98. In eighteen cases we reject the linear null at usual significance levels. In fourteen cases we are able to successfully fit STAR-type models. Simulation results show there is very little support for the Prebisch‐Singer hypothesis.
THE ACCRETION GEOMETRY IN RADIO-LOUD ACTIVE GALAXIES

We review the latest attempts to determine the accretion geometry in radio-loud active galactic nuclei (AGN). These objects, which comprise ~ 10–20% of the AGN population, produce powerful collimated radio jets that can extend thousands of parsecs from the center of the host galaxy. Recent multiwavelength surveys have shown that radio-loudness is more common in low-luminosity AGN than in higher luminosity Seyfert galaxies or quasars. These low-luminosity AGN have small enough accretion rates that they are most likely accreting via a geometrically thick and radiatively inefficient accretion flow. In contrast, X-ray spectroscopic observations of three higher luminosity broad-line radio galaxies (3C 120, 4C+74.26 and PG 1425+267) have found evidence for an untruncated thin disk extending very close to the black hole. These tentative detections indicate that, for this class of radio-loud AGN, the accretion geometry is very similar to their radio-quiet counterparts. These observations suggest that there are three conditions to jet formation that must be satisfied: the presence of a rapidly spinning black hole, an accretion flow with a large H/r ratio, and a favorable magnetic field geometry.
Efficient Monte Carlo Barrier Option Pricing When the Underlying Security Price Follows a Jump-Diffusion Process

We present efficient simulation procedures for pricing barrier options when the underlying security price follows a geometric Brownian motion with jumps. Metwally and Atiya [2002] developed a simulation approach for pricing knock-out options in the same setting, but no variance reduction was introduced. We improve upon Metwally and Atiya9s method by innovative applications of well-known variance reduction techniques. We also show how to use simulation to price knock-in options. Numerical examples show that our proposed Monte Carlo procedures lead to substantial variance reduction as well as a reduction in computing time.
Chemical segregation during bulk single crystal preparation of Ni–Mn–Ga ferromagnetic shape memory alloys

Abstract Preparation of bulk single crystals of the ferromagnetic shape memory alloy Ni2MnGa has been accomplished using the Bridgman method. Magnetic and magnetostrictive properties from samples sectioned from different portions of the crystal showed high variability, indicating significant chemical segregation occurred during single crystal growth. This chemical segregation during crystal growth implies that the compound Ni2MnGa does not melt congruently. Partial evaluation of the liquidus diagram of Ni–Mn–Ga by thermal analysis and microstructural evaluation has determined that the primary solidification surface for the Heusler alloy phase exists over a wide range of compositions. The primary solidification surface falls modestly in temperature with either increasing Mn or Ga concentration. The composition Ni50Mn25Ga25 melts incongruently over a temperature range of approximately 18°C. Characterization of the compositional variation along the growth direction in the single crystals was done using energy dispersive spectrometry and the results normalized against the fraction solidified. Compositional changes during solidification followed constant electron/atom (e/a) ratios over most of the length of the ingot. Under the single crystal growth conditions, the segregation pattern corresponds to a fully mixed condition and the data was fitted to a complete mixing model. Partitioning coefficients for the elemental constituents and the overall compositions were determined. The partitioning coefficients were found to be uniformly consistent between different growth runs, even though the overall compositions differed between crystals. The martensite transition temperatures along the length of the crystal were measured by differential scanning calorimetry and compared to predicted transition temperatures based on the e/a concentration.
Solving Quadratic Equations via PhaseLift When There Are About as Many Equations as Unknowns

This note shows that we can recover any complex vector $\boldsymbol {x}_{0} \in \mathbb {C}^{n}$ exactly from on the order of n quadratic equations of the form |?a i ,x 0?|2=b i , i=1,?,m, by using a semidefinite program known as PhaseLift. This improves upon earlier bounds in Candes et al. (Commun. Pure Appl. Math. 66:1241---1274, 2013), which required the number of equations to be at least on the order of nlogn. Further, we show that exact recovery holds for all input vectors simultaneously, and also demonstrate optimal recovery results from noisy quadratic measurements; these results are much sharper than previously known results.
Minimal Realizations of Linear Systems: The “Shortest Basis” Approach

Given a discrete-time linear system C, a shortest basis for C is a set of linearly independent generators for C with the least possible lengths. A basis B is a shortest basis if and only if it has the predictable span property (i.e., has the predictable delay and degree properties, and is non-catastrophic), or alternatively if and only if it has the subsystem basis property (for any interval J, the generators in B whose span is in J is a basis for the subsystem CJ). The dimensions of the minimal state spaces and minimal transition spaces of C are simply the numbers of generators in a shortest basis B that are active at any given state or symbol time, respectively. A minimal linear realization for C in controller canonical form follows directly from a shortest basis for C, and a minimal linear realization for C in observer canonical form follows directly from a shortest basis for the orthogonal system C⊥. This approach seems conceptually simpler than that of classical minimal realization theory.