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Staves, Daniel R., John L. Salmon, and Walter E. Red. "Associative CAD references in the neutral parametric canonical form." Computer-Aided Design and Applications 14, no. 4 (December 16, 2016): 408–21. http://dx.doi.org/10.1080/16864360.2016.1257184.
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Santra, Shyam Sundar, Abhay Kumar Sethi, Osama Moaaz, Khaled Mohamed Khedher, and Shao-Wen Yao. "New Oscillation Theorems for Second-Order Differential Equations with Canonical and Non-Canonical Operator via Riccati Transformation." Mathematics 9, no. 10 (May 14, 2021): 1111. http://dx.doi.org/10.3390/math9101111.
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In this work, we prove some new oscillation theorems for second-order neutral delay differential equations of the form (a(ξ)((v(ξ)+b(ξ)v(ϑ(ξ)))′))′+c(ξ)G1(v(κ(ξ)))+d(ξ)G2(v(ς(ξ)))=0 under canonical and non-canonical operators, that is, ∫ξ0∞dξa(ξ)=∞ and ∫ξ0∞dξa(ξ)<∞. We use the Riccati transformation to prove our main results. Furthermore, some examples are provided to show the effectiveness and feasibility of the main results.
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Aziz, Taha, Aeeman Fatima, and Chaudry Masood Khalique. "Integrability analysis of the partial differential equation describing the classical bond-pricing model of mathematical finance." Open Physics 16, no. 1 (December 14, 2018): 766–79. http://dx.doi.org/10.1515/phys-2018-0096.
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AbstractThe invariant approach is employed to solve the Cauchy problem for the bond-pricing partial differential equation (PDE) of mathematical finance. We first briefly review the invariant criteria for a scalar second-order parabolic PDE in two independent variables and then utilize it to reduce the bond-pricing equation to different Lie canonical forms. We show that the invariant approach aids in transforming the bond-pricing equation to the second Lie canonical form and that with a proper parametric selection, the bond-pricing PDE can be converted to the first Lie canonical form which is the classical heat equation. Different cases are deduced for which the original equation reduces to the first and second Lie canonical forms. For each of the cases, we work out the transformations which map the bond-pricing equation into the heat equation and also to the second Lie canonical form. We construct the fundamental solutions for the bond-pricing model via these transformations by utilizing the fundamental solutions of the classical heat equation as well as solution to the second Lie canonical form. Finally, the closed-form analytical solutions of the Cauchy initial value problems for the bond-pricing model with proper choice of terminal conditions are obtained.
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Chand, Savin S., Kevin J. Tory, John L. McBride, Matthew C. Wheeler, Richard A. Dare, and Kevin J. E. Walsh. "The Different Impact of Positive-Neutral and Negative-Neutral ENSO Regimes on Australian Tropical Cyclones." Journal of Climate 26, no. 20 (October 4, 2013): 8008–16. http://dx.doi.org/10.1175/jcli-d-12-00769.1.
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Abstract The number of tropical cyclones (TCs) in the Australian region exhibits a large variation between different ENSO regimes. While the difference in TC numbers and spatial distribution of genesis locations between the canonical El Niño and La Niña regimes is well known, the authors demonstrate that a statistically significant difference in TC numbers also exists between the recently identified negative-neutral and positive-neutral regimes. Compared to the negative-neutral and La Niña regimes, significantly fewer TCs form in the Australian region during the positive-neutral regime, particularly in the eastern subregion. This difference is attributed to concomitant changes in various large-scale environmental conditions such as sea level pressure, relative vorticity, vertical motion, and sea surface temperature.
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Glöckner, Andreas, Baiba Renerte, and Ulrich Schmidt. "Violations of coalescing in parametric utility measurement." Theory and Decision 89, no. 4 (July 13, 2020): 471–501. http://dx.doi.org/10.1007/s11238-020-09761-5.
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Abstract The majority consensus in the empirical literature is that probability weighting functions are typically inverse-S shaped, that is, people tend to overweight small and underweight large probabilities. A separate stream of literature has reported event-splitting effects (also called violations of coalescing) and shown that they can explain violations of expected utility. This leads to the questions whether (1) the observed shape of weighting functions is a mere consequence of the coalesced presentation and, more generally, whether (2) preference elicitation should rely on presenting lotteries in a canonical split form instead of the commonly used coalesced form. We analyze data from a binary choice experiment where all lottery pairs are presented in both split and coalesced forms. Our results show that the presentation in a split form leads to a better fit of expected utility theory and to probability weighting functions that are closer to linear. We thus provide some evidence that the extent of probability weighting is not an ingrained feature, but rather a result of processing difficulties.
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Parvan, A. S. "Nonextensive statistics of Landsberg-Vedral entropy." EPJ Web of Conferences 204 (2019): 03005. http://dx.doi.org/10.1051/epjconf/201920403005.
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The general formalism for the nonextensive statistics based on the Landsberg-Vedral parametric entropy in the framework of the microcanonical, canonical and grand canonical ensembles was derived. The formulas for the first law of thermodynamics and the thermodynamic quantities in the terms of ensemble averages were obtained in a general form. It was found that under the transformation q → 2 – q the probabilities of microstates of the nonextensive statistics based on the Landsberg-Vedral entropy with the standard expectation values formally resemble the corresponding probabilities of the Tsallis statistics with the generalized expectation values.
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D. Apale, Tejal, and Ajay B. Patil. "Optimization study of fuzzy parametric uncertain system." IAES International Journal of Artificial Intelligence (IJ-AI) 8, no. 1 (March 1, 2019): 14. http://dx.doi.org/10.11591/ijai.v8.i1.pp14-25.
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This paper deals with the analysis and design of the optimal robust controller for the fuzzy parametric uncertain system. An LTI system in which coefficients depends on parameters described by a fuzzy function is called as fuzzy parametric uncertain system. By optimal control design, we get control law and feedback gain matrix which can stabilize the system. The robust controller design is a difficult task so we go for the optimal control approach. The system can be converted into state space controllable canonical form with the α-cut property fuzzy. For optimal control design, we find control law and get the feedback gain matrix which can stabilize the system and optimizes the cost function. Stability analysis is done by using the Kharitonov theorem and Lyapunov-Popov method. The proposed method applied to a response of Continuous Stirred Tank Reactor (CSTR).
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Duda, Józef. "Parametric optimization of neutral linear system with two delays with P-controller." Archives of Control Sciences 21, no. 4 (January 1, 2011): 363–72. http://dx.doi.org/10.2478/v10170-011-0002-6.
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Parametric optimization of neutral linear system with two delays with P-controller In the paper the problem of parametric optimization of a linear neutral system with two delays accomplished with respect to the integral quadratic performance index is formulated and solved. A method of computing the value of performance index relies on determining such a Lyapunov functional defined on the state space that its value for the initial state is equal to that of performance index. In the paper the form of Lyapunov functional is assumed and a method of computing its coefficients is given. An example illustrating the application of the theory discussed is presented. It concerns a system with the P-controller designed to control a plant with two delays both retarded and neutral type. For such a system the value of the considered performance index is determined.
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Duda, Józef. "Parametric optimization of a neutral system with two delays and PD-controller." Archives of Control Sciences 23, no. 2 (June 1, 2013): 131–43. http://dx.doi.org/10.2478/acsc-2013-0008.
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In this paper a parametric optimization problem for a linear neutral system with two delays with an integral quadratic performance index is formulated and solved. The method of computing of a performance index value bases on determining of a Lyapunov functional defined on a state space such that its value for an initial state is equal to a performance index value. In the paper a form of a Lyapunov functional is assumed and a method of computing its coefficients is given. An example illustrating the application of discussed theory is presented. It concerns the system with a PD-controller designed to control a plant with two delays both retarded and neutral type. For such system a value of considered performance index is determined.
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Sinelshchikov, Dmitry. "On an integrability criterion for a family of cubic oscillators." AIMS Mathematics 6, no. 11 (2021): 12902–10. http://dx.doi.org/10.3934/math.2021745.
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<abstract><p>In this work we consider a family of cubic, with respect to the first derivative, nonlinear oscillators. We obtain the equivalence criterion for this family of equations and a non-canonical form of Ince Ⅶ equation, where as equivalence transformations we use generalized nonlocal transformations. As a result, we construct two integrable subfamilies of the considered family of equations. We also demonstrate that each member of these two subfamilies possesses an autonomous parametric first integral. Furthermore, we show that generalized nonlocal transformations preserve autonomous invariant curves for the equations from the studied family. As a consequence, we demonstrate that each member of these integrable subfamilies has two autonomous invariant curves, that correspond to irreducible polynomial invariant curves of the considered non-canonical form of Ince Ⅶ equation. We illustrate our results by two examples: An integrable cubic oscillator and a particular case of the Liénard (4, 9) equation.</p></abstract>
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Kayzer, Dariusz. "A note on testing hypotheses concerning interaction with special reference to a graphical presentation in the space of canonical variates." Biometrical Letters 56, no. 1 (June 1, 2019): 89–104. http://dx.doi.org/10.2478/bile-2019-0008.
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SummaryResults of ecological studies that involve the use of multivariate analysis of variance techniques for testing various hypotheses, interesting from the point of view of comparing the linear functions of parameters, were considered. For testing the most interesting hypotheses on a variety of interaction effects and on contrasts of class means, the application of a multivariate test statistic is recommended. Canonical variate analysis is used for graphical presentation of the results of multidimensional experiments. In this paper it is shown how a generalized form of canonical variate analysis can be useful to reveal which parametric functions of a multivariate analysis of variance model are responsible for rejecting the linear hypothesis. As an example, an analysis was made of an ecological study of trace element accumulation in plants of Italian ryegrass as a method of biomonitoring of air pollution.
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Hamerly, Ryan, Kensuke Inaba, Takahiro Inagaki, Hiroki Takesue, Yoshihisa Yamamoto, and Hideo Mabuchi. "Topological defect formation in 1D and 2D spin chains realized by network of optical parametric oscillators." International Journal of Modern Physics B 30, no. 25 (September 28, 2016): 1630014. http://dx.doi.org/10.1142/s0217979216300140.
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A network of optical parametric oscillators (OPOs) is used to simulate classical Ising and XY spin chains. The collective nonlinear dynamics of this network, driven by quantum noise rather than thermal fluctuations, seeks out the Ising/XY ground state as the system transitions from below to above the lasing threshold. We study the behavior of this “Ising machine” for three canonical problems: a 1D ferromagnetic spin chain, a 2D square lattice and problems where next-nearest-neighbor couplings give rise to frustration. If the pump turn-on time is finite, topological defects form (domain walls for the Ising model, winding number and vortices for XY) and their density can be predicted from a numerical model involving a linear “growth stage” and a nonlinear “saturation stage”. These predictions are compared against recent data for a 10,000-spin 1D Ising machine.
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Georgiou, Nikos. "On area stationary surfaces in the space of oriented geodesics of hyperbolic 3-space." MATHEMATICA SCANDINAVICA 111, no. 2 (December 1, 2012): 187. http://dx.doi.org/10.7146/math.scand.a-15224.
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We study area-stationary surfaces in the space $\mathbf{L}(\mathbf{H}^3)$ of oriented geodesics of hyperbolic 3-space, endowed with the canonical neutral Kähler structure. We prove that every holomorphic curve in $\mathbf{L}(\mathbf{H}^3)$ is an area-stationary surface. We then classify Lagrangian area-stationary surfaces $\Sigma$ in $\mathbf{L}(\mathbf{H}^3)$ and prove that the family of parallel surfaces in $\mathbf{H}^3$ orthogonal to the geodesics $\gamma\in \Sigma$ form a family of equidistant tubes around a geodesic. Finally we find an example of a two parameter family of rotationally symmetric area-stationary surfaces that are neither Lagrangian nor holomorphic.
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Irimata, Katherine E., and Jeffrey R. Wilson. "Modification of the generalized quasi-likelihood model in the analysis of the Add Health study." Statistical Methods in Medical Research 29, no. 8 (November 5, 2019): 2087–99. http://dx.doi.org/10.1177/0962280219884980.
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The relationship between the mean and variance is an implicit assumption of parametric modeling. While many distributions in the exponential family have a theoretical mean–variance relationship, it is often the case that the data under investigation are correlated, thus varying from the relation. We present a generalized method of moments estimation technique for modeling certain correlated data by adjusting the mean–variance relationship parameters based on a canonical parameterization. The proposed mean–variance form describes overdispersion using two parameters and implements an adjusted canonical parameter which makes this approach feasible for all distributions in the exponential family. Test statistics and confidence intervals are used to measure the deviations from the mean–variance relation parameters. We use the modified relation as a means of fitting generalized quasi-likelihood models to correlated data. The performance of the proposed modified generalized quasi-likelihood model is demonstrated through a simulation study and the importance of accounting for overdispersion is highlighted through the evaluation of adolescent obesity data collected from a U.S. longitudinal study.
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SOW, C. L., and T. T. TRUONG. "QUANTUM GROUP APPROACH TO A SOLUBLE VERTEX MODEL WITH GENERALIZED ICE RULE." International Journal of Modern Physics A 11, no. 10 (April 20, 1996): 1747–61. http://dx.doi.org/10.1142/s0217751x96000936.
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Using the representation of the quantum group SL q(2) by the Weyl operators of the canonical commutation relations in quantum mechanics, we construct and solve a new vertex model on a square lattice. Random variables on horizontal bonds are Ising variables, and those on the vertical bonds take half positive integer values. The vertex is subjected to a generalized form of the so-called “ice rule,” its property is studied in detail and its free energy calculated with the method of quantum inverse scattering. Remarkably, in analogy with the usual six-vertex model, there exists a “free-fermion” limit with a novel rich operator structure. The existing algebraic structure suggests a possible connection with a lattice neutral plasma of charges, via the fermion-boson correspondence.
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Devereaux, Zachary J., Y. Zhu, and MT Rodgers. "Relative glycosidic bond stabilities of naturally occurring methylguanosines: 7-methylation is intrinsically activating." European Journal of Mass Spectrometry 25, no. 1 (September 6, 2018): 16–29. http://dx.doi.org/10.1177/1469066718798097.
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The frequency and diversity of posttranscriptional modifications add an additional layer of chemical complexity beyond canonical nucleic acid sequence. Methylations are particularly frequently occurring and often highly conserved throughout the kingdoms of life. However, the intricate functions of these modified nucleic acid constituents are often not fully understood. Systematic foundational research that reduces systems to their minimum constituents may aid in unraveling the complexities of nucleic acid biochemistry. Here, we examine the relative intrinsic N-glycosidic bond stabilities of guanosine and five naturally occurring methylguanosines (O2′-, 1-, 7-, N2,N2-di-, and N2,N2,O2′-trimethylguanosine) probed by energy-resolved collision-induced dissociation tandem mass spectrometry and complemented with quantum chemical calculations. Apparent glycosidic bond stability is generally found to increase with increasing methyl substitution (canonical < mono- < di- < trimethylated). Many biochemical transformations, including base excision repair mechanisms, involve protonation and/or noncovalent interactions to increase nucleobase leaving-group ability. The protonated gas-phase methylguanosines require less activation energy for glycosidic bond cleavage than their sodium cationized forms. However, methylation at the N7 position intrinsically weakens the glycosidic bond of 7-methylguanosine more significantly than subsequent cationization, and thus 7-methylguanosine is suggested to be under perpetually activated conditions. N7 methylation also alters the nucleoside geometric preferences relative to the other systems, including the nucleobase orientation in the neutral form, sugar puckering in the protonated form, and the preferred protonation and sodium cation binding sites. All of the methylated guanosines examined here are predicted to have proton affinities and gas-phase basicities that exceed that of canonical guanosine. Additionally, the proton affinity and gas-phase basicity trends exhibit a roughly inverse correlation with the apparent glycosidic bond stabilities.
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RACZ, J. P., and J. F. SCOTT. "Parametric instability in a rotating cylinder of gas subject to sinusoidal axial compression. Part 1. Linear theory." Journal of Fluid Mechanics 595 (January 8, 2008): 265–90. http://dx.doi.org/10.1017/s0022112007009238.
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An analysis is presented of parametric instability in a finite-length rotating cylinder subject to periodic axial compression by small sinusoidal oscillations of one of its ends (the ‘piston’). The instability is due to resonant interactions between inertial-wave (Kelvin) modes of the cylinder and the oscillatory compression and is resisted by viscosity, acting both through thin boundary layers and throughout the volume, the two mechanisms proving crucial for a satisfactory description. Instability is found to take the form of either a single axisymmetric mode with frequency near to half that of compression, or a pair of non-axisymmetric modes of the same azimuthal and axial orders and oppositely signed frequencies, whose difference is close to the compression frequency. Thus, in the axisymmetric case, instability leads to spontaneous growth of a system of one or more oscillating toroidal vortices encircling the cylinder axis, while the differing frequencies of the two modes of non-axisymmetric instability implies an oscillatory aperiodic flow. The neutral curves giving the threshold for instability are determined for all modes/mode pairs. For a given mode or mode pair, the neutral curve shows a critical piston amplitude dependent on rotational Reynolds number and cylinder aspect ratio, below which instability does not occur, and above which there is instability provided the compression frequency is chosen to lie in a band centred on the exact resonance condition.
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Hung, N. M. "L’instabilité structurelle dans le modèle de croissance avec ressource non renouvelable." Articles 57, no. 3 (January 21, 2009): 387–406. http://dx.doi.org/10.7202/600991ar.
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ABSTRACT The analysis of the question of structural stability in the growth model with exhaustible resources consists essentially in the examination of the long term values of capital and consumption as they result from parametric variations. The parameters used in this study relate to ethic (discount rate) and to technology (elasticity of substitution between resource and capital and technical progress). Considering the structural stability, the already known results are generalized in two directions. First, a general description of production technology is made. Second, a special attention is given to the question of technological innovation. An analysis of the form of the Hicksian neutral technical progress is made considering an economy with a Cobb-Douglas production function.
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WEBB, G. M., A. R. ZAKHARIAN, M. BRIO, and G. P. ZANK. "Parametric instabilities and wave coupling in Alfvén simple waves." Journal of Plasma Physics 66, no. 3 (September 2001): 167–212. http://dx.doi.org/10.1017/s0022377801001283.
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A wave coupling formalism for magnetohydrodynamic (MHD) waves in a non-uniform background flow is used to study parametric instabilities of the large-amplitude, circularly polarized, simple plane Alfvén wave in one Cartesian space dimension. The large-amplitude Alfvén wave (the pump wave) is regarded as the background flow, and the seven small-amplitude MHD waves (the backward and forward fast and slow magnetoacoustic waves, the backward and forward Alfvén waves, and the entropy wave) interact with the pump wave via wave coupling coefficients that depend on the gradients and time dependence of the background flow. The dispersion equation for the waves D(k,ω) = 0 obtained from the wave coupling equations reduces to that obtained by previous authors. The general solution of the initial value problem for the waves is obtained by Fourier and Laplace transforms. The dispersion function D(k,ω) is a fifth-order polynomial in both the wavenumber k and the frequency ω. The regions of instability and the neutral stability curves are determined. Instabilities that arise from solving the dispersion equation D(k,ω) = 0, both in the form ω = ω(k), where k is real, and in the form k = k(ω), where ω is real, are investigated. The instabilities depend parametrically on the pump wave amplitude and on the plasma beta. The wave interaction equations are also studied from the perspective of a single master wave equation, with multiple wave modes, and with a source term due to the entropy wave. The wave hierarchies for short- and long-wavelength waves of the master wave equation are used to discuss wave stability. Expanding the dispersion equation for the different long-wavelength eigenmodes about k = 0 yields either the linearized Korteweg–deVries equation or the Schrödinger equation as the generic wave equation at long-wavelengths. The corresponding short-wavelength wave equations are also obtained. Initial value problems for the wave interaction equations are investigated. An inspection of the double-root solutions of the dispersion equation for k, satisfying the equations D(k,ω) = 0 and ∂D(k,ω) = ∂k = 0 and pinch point analysis shows that the solutions of the wave interaction equations for hump or pulse-like initial data develop an absolute instability. Fourier solutions and asymptotic analysis are used to study the absolute instability.
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Datta, Sambit, and David Beynon. "A Computational Approach to the Reconstruction of Surface Geometry from Early Temple Superstructures." International Journal of Architectural Computing 3, no. 4 (December 2005): 471–86. http://dx.doi.org/10.1260/147807705777781068.
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Recovering the control or implicit geometry underlying temple architecture requires bringing together fragments of evidence from field measurements, relating these to mathematical and geometric descriptions in canonical texts and proposing “best-fit” constructive models. While scholars in the field have traditionally used manual methods, the innovative application of niche computational techniques can help extend the study of artefact geometry. This paper demonstrates the application of a hybrid computational approach to the problem of recovering the surface geometry of early temple superstructures. The approach combines field measurements of temples, close-range architectural photogrammetry, rule-based generation and parametric modelling. The computing of surface geometry comprises a rule-based global model governing the overall form of the superstructure, several local models for individual motifs using photogrammetry and an intermediate geometry model that combines the two. To explain the technique and the different models, the paper examines an illustrative example of surface geometry reconstruction based on studies undertaken on a tenth century stone superstructure from western India. The example demonstrates that a combination of computational methods yields sophisticated models of the constructive geometry underlying temple form and that these digital artefacts can form the basis for in depth comparative analysis of temples, arising out of similar techniques, spread over geography, culture and time.
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RIGATOS, GERASIMOS, and EFTHYMIA RIGATOU. "SYNCHRONIZATION OF CIRCADIAN OSCILLATORS AND PROTEIN SYNTHESIS CONTROL USING THE DERIVATIVE-FREE NONLINEAR KALMAN FILTER." Journal of Biological Systems 22, no. 04 (November 11, 2014): 631–57. http://dx.doi.org/10.1142/s0218339014500259.
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The paper proposes a new method for synchronization of coupled circadian cells and for nonlinear control of the associated protein synthesis process using differential flatness theory and the derivative-free nonlinear Kalman filter. By proving that the dynamic model of the FRQ protein synthesis is a differentially flat one, its transformation to the linear canonical (Brunovsky) form becomes possible. For the transformed model, one can find a state feedback control input that makes the oscillatory characteristics in the concentration of the FRQ protein vary according to desirable setpoints. To estimate nonmeasurable elements of the state vector, the derivative-free nonlinear Kalman filter is used. The derivative-free nonlinear Kalman filter consists of the standard Kalman filter recursion on the linearized equivalent model of the coupled circadian cells and on computation of state and disturbance estimates using the diffeomorphism (relations about state variables transformation) provided by differential flatness theory. Moreover, to cope with parametric uncertainties in the model of the FRQ protein synthesis and with stochastic disturbances in measurements, the derivative-free nonlinear Kalman filter is redesigned in the form of a disturbance observer. The efficiency of the proposed Kalman filter-based control scheme is tested through simulation experiments.
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Gonçalves, Bruna, Nuno Azevedo, Hugo Osório, Mariana Henriques, and Sónia Silva. "Revealing Candida glabrata biofilm matrix proteome: global characterization and pH response." Biochemical Journal 478, no. 4 (February 26, 2021): 961–74. http://dx.doi.org/10.1042/bcj20200844.
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Candida glabrata is a clinically relevant human pathogen with the ability to form high recalcitrant biofilms that contribute to the establishment and persistence of infection. A defining trait of biofilms is the auto-produced matrix, which is suggested to have structural, virulent and protective roles. Thus, elucidation of matrix components, their function and modulation by the host environment is crucial to disclose their role in C. glabrata pathogenesis. As a major step toward this end, this study aimed to reveal, for the first time, the matrix proteome of C. glabrata biofilms, to characterize it with bioinformatic tools and to study its modulation by the environmental pH (acidic and neutral). The results showed the presence of several pH-specific matrix proteins (51 acidic- and 206 neutral-specific) and also proteins commonly found at both pH conditions (236). Of note, several proteins related to mannan and β-glucan metabolism, which have a potential role in the delivery/organization of carbohydrates in the matrix, were found in both pH conditions but in much higher quantity under the neutral environment. Additionally, several virulence-related proteins, including epithelial adhesins, yapsins and moonlighting enzymes, were found among matrix proteins. Importantly, several proteins seem to have a non-canonical secretion pathway and Pdr1 was found to be a potential regulator of matrix proteome. Overall, this study indicates a relevant impact of environmental cues in the matrix proteome and provides a unique resource for further functional investigation of matrix proteins, contributing to the identification of potential targets for the development of new therapies against C. glabrata biofilms.
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Margaritopoulos, J. T., J. A. Tsitsipis, E. Zintzaras, and R. L. Blackman. "Host-correlated morphological variation of Myzus persicae (Hemiptera: Aphididae) populations in Greece." Bulletin of Entomological Research 90, no. 3 (June 2000): 233–44. http://dx.doi.org/10.1017/s0007485300000353.
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Morphological variation in nine characters of 157 clones of Myzus persicae(Sulzer) was examined by multivariate analysis. The clones were collected from peach, Prunus persica, the primary host and the secondary hosts tobacco, Nicotiana tabacum, cabbage, Brassica oleracea, sugarbeet, Beta vulgaris and pepper Capsicum annuum. The 156 clones originated from various regions of Greece, both in the north, where a large part of the population has an annual bisexual generation on peach, and in more southerly regions, where populations are predominantly unisexual. One clone was collected from tobacco in Caserta, Italy. All clones were laboratory-reared on potato. Canonical variate analysis, hierarchical cluster analysis and a non-parametric classification tree method both revealed morphological differences associated with the host-plant on which they were collected. The scores of the first two canonical variates separated the tobacco-feeding clones from those originating from other secondary host-plants. However, in tobacco-growing areas the tobacco-feeding form predominated in spring populations on peach, and was sometimes found on other secondary hosts. In addition, using cluster analysis, the clones from tobacco which were sampled in the most southeasterly region showed a relatively large phenotypic distance from those collected further north and west. Moreover, clonal phenotypes were affected both by host plant and by long-term parthenogenetic rearing. However, in spite of these effects, the tobacco form was generally distinguishable from aphids originating from other hosts, indicating that the difference must have a genetic basis. In separate analyses of the clones originating from secondary hosts no association was found between morphology and either life cycle category or colour. Discriminant analysis showed that 89% of 1723 specimens could be correctly classified into the two groups.
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Jud, Dominic, Ilmar Hurkxkens, Christophe Girot, and Marco Hutter. "Robotic embankment." Construction Robotics 5, no. 2 (June 2021): 101–13. http://dx.doi.org/10.1007/s41693-021-00061-0.
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AbstractAutomating earth-moving tasks has the potential to resolve labour-shortage, allow for unseen designs and foster sustainability through using on-site materials. In this interdisciplinary project involving robotics and landscape architecture, we combine our previous work on autonomous excavation of free-form shapes, dynamic landscape design and terrain modelling tools into a robotic landscape system. It tightly connects survey, design and fabrication to exchange information in real-time during fabrication. We purposely built a LiDAR survey drone for tight integration. The design environment contains terrain modelling tools to balance cut and fill volumes for material-neutral, on-site construction. Its parametric nature allows it to adapt the geometry to changing site conditions during fabrication. Our autonomous walking excavator is used to create these free-form shapes in natural granular material. We propose an excavation planner for free-form embankments that computes the next excavation location and subsequently the location where the excavated soil should be dumped. This robotic excavation system achieves the world’s first autonomous completion of free-form embankments with high accuracy. A $$20\hbox { m}$$ 20 m long S-shaped and a two-faced embankment with a corner with roughly 0.03–0.05 m average error were created.
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Morkhade, Samadhan G., and Laxmikant M. Gupta. "ANALYSIS OF STEEL I-BEAMS WITH RECTANGULAR WEB OPENINGS: EXPERIMENTAL AND FINITE ELEMENT INVESTIGATION." Engineering Structures and Technologies 7, no. 1 (December 15, 2015): 13–23. http://dx.doi.org/10.3846/2029882x.2015.1085332.
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Steel I-shaped beams with web openings of shapes like hexagonal, circular and rectangular at regular intervals have been used since last 60–70 years. Therefore aim of this paper is to examine the behaviour of steel I-beams with rectangular web openings by performinganexperimental and parametric study. A parametric study based on finite element analysis consists of effect of fillet radius, aspect ratio of rectangular openings, stiffeners position around the openings and effect of positions of openings on load carrying capacities of steel beam with rectangular web openings was carried out by using a commercial finite element software ANSYS v.12. An overall study of such type of beam was carried out and results shows that rectangular openings having fillet radius either 2 times thickness of web or 25 mm (whichever is minimum), aspect ratio of 1.6 and reinforcement either in the form of horizontal or vertical stiffeners around the web openings found to be very effective. The fillet radius and stiffeners also affect the stress distribution around the corner regions of openings. Load carrying capacities of perforated beams are almost equal to plain-webbed beams, when openings are placed within middle two-third(neutral zone) of the span.
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Mahmud, Mahmud, Heru Joko Budirianto, Wahyudi Wahyudi, and Ambar Kusumandari. "A study conversion to be mining cement in Maruni protected forest Manokwari Regency." Jurnal Pengelolaan Sumberdaya Alam dan Lingkungan (Journal of Natural Resources and Environmental Management) 10, no. 3 (November 16, 2020): 545–58. http://dx.doi.org/10.29244/jpsl.10.3.545-558.
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Protected forests play an important role in supporting human life, protecting land and water and preventing the dangers of flooding and landslides, but a lot of conversions have taken place today. Research-based on techniques for observation, interviews, and case studies. Measurement of respondents' perceptions and attitudes is carried out using instruments in the form of questionnaires that refer to the Likert scale. Data analysis was performed descriptively to describe the level of perception, attitude with simple non parametric linear regression. Maruni protected forest has the potential of limestone with 11 mineral elements, 5 of which are the largest Ca (93.62%), Si (2.45%), Mg (1.58%), Al (0.97%) ) and K (0.47%). This forest allows conversion area, from an area of 969.84 ha with limestone potential of only 250 ha (25.78%), another 719.84 ha (74.22%) can still be designated as a protected forest. The public perception of conversion to cement mining was 59.03% negative, 14.83% neutral and 26.12% positive. While the attitudes of the community 43.1% accept, 38.94% neutral and 47.92% reject the conversion to become cement mining. The community hopes that there will be economic improvement, community empowerment and employment, especially affected communities.
Keywords: Conversion, cement mining, Maruni protected forest/HLM, perception, attitude
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GALTIER, S., E. ZIENICKE, H. POLITANO, and A. POUQUET. "Parametric investigation of self-similar decay laws in MHD turbulent flows." Journal of Plasma Physics 61, no. 3 (April 1999): 507–41. http://dx.doi.org/10.1017/s0022377899007643.
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An investigation of the decay laws of energy and of higher moments of the Elsässer fields z±=v±b in the self-similar regime of magnetohydrodynamic (MHD) turbulence is presented, using phenomenological models as well as two-dimensional numerical simulations with periodic boundary conditions and up to 20482 grid points. The results are compared with the generalization of the parameter-free model derived by Galtier et al. [Phys. Rev. Lett.79, 2807 (1997)], which takes into account the slowing down of the dynamics due to the propagation of Alfvén waves. The new model developed here allows for a study in terms of one parameter governing the wavenumber dependence of the energy spectrum at scales of the order of (and larger than) the integral scale of the flow. The one-dimensional compressible case is also dealt with in two of its simplest configurations. Computations are performed for a standard Laplacian diffusion as well as with a hyperdiffusive algorithm. The results are sensitive to the amount of correlation between the velocity and the magnetic field, but rather insensitive to all other parameters such as the initial ratio of kinetic to magnetic energy or the presence or absence of a uniform component of the magnetic field. In all cases, the decay is significantly slower than for neutral fluids in a way that favours for MHD flows the phenomenology of Iroshnikov [Soviet Astron.7, 566 (1963)] and Kraichnan [Phys. Fluids8, 1385 (1965)] as opposed to that of Kolmogorov [Dokl. Akad. Nauk. SSSR31, 538 (1941)]. The temporal evolution of q-moments of the generalized vorticities 〈[mid ]ω±[mid ]q〉 =〈[mid ]ω±j[mid ]q〉 up to order q=10 is also given, and is compared with the prediction of the model. Less agreement obtains as q grows – a fact probably due to intermittency and the development of coherent structures in the form of eddies, and of vorticity and current sheets.
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Domina, Olena. "FEATURES OF FINDING OPTIMAL SOLUTIONS IN NETWORK PLANNING." EUREKA: Physics and Engineering, no. 6 (November 30, 2020): 82–96. http://dx.doi.org/10.21303/2461-4262.2020.001471.
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The object of research is a test network diagram, in relation to which the task of minimizing the objective function qmax/qmin→min is posed, which requires maximizing the uniformity of the workload of personnel when implementing an arbitrary project using network planning. The formulation of the optimization problem, therefore, assumed finding such times of the beginning of the execution of operations, taken as input variables, in order to ensure the minimum value of the ratio of the peak workload of personnel to the minimum workload.
The procedure for studying the response surface proposed in the framework of RSM is described in relation to the problem of optimizing network diagrams. A feature of this procedure is the study of the response surface by a combination of two methods – canonical transformation and ridge analysis. This combination of methods for studying the response surface allows to see the difference between optimal solutions in the sense of "extreme" and in the sense of "best". For the considered test network diagram, the results of the canonical transformation showed the position on the response surface of the extrema in the form of maxima, which is unacceptable for the chosen criterion for minimizing the objective function qmax/qmin→min. It is shown that the direction of movement towards the best solutions with respect to minimizing the value of the objective function is determined on the basis of a parametric description of the objective function and the restrictions imposed by the experiment planning area. A procedure for constructing nomograms of optimal solutions is proposed, which allows, after its implementation, to purposefully choose the best solutions based on the real network diagrams of your project
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Kondo, Jiro, Tom Yamada, Chika Hirose, Itaru Okamoto, Yoshiyuki Tanaka, and Akira Ono. "Crystal structure of metallo-DNA duplex containing T-Hg(II)-T base pairs." Acta Crystallographica Section A Foundations and Advances 70, a1 (August 5, 2014): C1375. http://dx.doi.org/10.1107/s2053273314086240.
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The DNA duplex containing mercury-mediated base pairs (T-Hg(II)-T) is an attractive biomacromolecular nanomaterials. In a recent study, it was confirmed that the Hg(II) ion significantly stabilizes a DNA duplex by binding selectively to a T-T mispair [1]. Based on the phenomenon observed, a DNA-based sensing system that selectively and sensitively detects Hg(II) ions in aqueous solution was developed [2]. In the present study, we have solved the first crystal structure of a B-form DNA duplex containing two consecutive T-Hg(II)-T base pairs [3]. The Hg(II) ion occupies the center between two T residues. The geometry of the T-Hg(II)-T base pair is very similar to that of the canonical Watson-Crick base pairs. The distance of N3-Hg(II) bond is 2.0 Å, suggesting that the N3 nitrogen releases an imino-proton even at neutral pH (pKa of N3 position of T is 9.8) and directly bonds to Hg(II). In the B-form DNA, the helical axis runs through the center of base pairs, and the Hg(II) ions are therefore aligned along the helical axis. The distance between the two neighboring Hg(II) ions is 3.3 Å. The relatively short Hg(II)-Hg(II) distance indicates that the metallophilic attraction could exit between them and may stabilize the B-form duplex. To support this, the DNA duplex is largely distorted and adopts an unusual non-helical conformation in the absence of Hg(II). In conclusion, the Hg(II) ion is essential for maintaining the B-form conformation of the DNA duplex containing T-T mispairs. The structure of the Hg(II)-DNA hybrid duplex itself and the Hg(II)-induced structural switching from the non-helical form to the B-form provide the basis for the structure-based design of metal-conjugated nucleic acid nanomaterials.
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Rigatos, Gerasimos G. "Control and disturbances compensation in underactuated robotic systems using the derivative-free nonlinear Kalman filter." Robotica 35, no. 3 (October 2, 2015): 687–711. http://dx.doi.org/10.1017/s0263574715000776.
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SUMMARYThe Derivative-free nonlinear Kalman Filter is used for developing a robust controller which can be applied to underactuated MIMO robotic systems. The control problem for underactuated robots is non-trivial and becomes further complicated if the robot is subjected to model uncertainties and external disturbances. Using differential flatness theory it is shown that the model of a closed-chain 2-DOF robotic manipulator can be transformed to linear canonical form. For the linearized equivalent of the robotic system it is shown that a state feedback controller can be designed. Since certain elements of the state vector of the linearized system cannot be measured directly, it is proposed to estimate them with the use of a novel filtering method, the so-called Derivative-free nonlinear Kalman Filter. Moreover, by redesigning the Kalman Filter as a disturbance observer, it is shown that one can estimate simultaneously external disturbance terms that affect the robotic model or disturbance terms which are associated with parametric uncertainty. The efficiency of the proposed Kalman Filter-based control scheme is tested in the case of a 2-DOF planar robotic manipulator that has the structure of a closed-chain mechanism.
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Guo, Zhongjie, Wei Wei, Maochun Wang, Jian Li, Shaowei Huang, Laijun Chen, and Shengwei Mei. "Characterizing and Visualizing the Impact of Energy Storage on Renewable Energy Curtailment in Bulk Power Systems." Applied Sciences 11, no. 3 (January 26, 2021): 1135. http://dx.doi.org/10.3390/app11031135.
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The uncertain natures of renewable energy lead to its underutilization; energy storage unit (ESU) is expected to be one of the most promising solutions to this issue. This paper evaluates the impact of ESUs on renewable energy curtailment. For any fixed renewable power output, the evaluation model minimizes the total amount of curtailment and is formulated as a mixed integer linear program (MILP) with the complementarity constraints on the charging and discharging behaviors of ESUs; by treating the power and energy capacities of ESUs as parameters, the MILP is transformed into a multi-parametric MILP (mp-MILP), whose optimal value function (OVF) explicitly maps the parameters to the renewable energy curtailment. Further, given the inexactness of uncertainty’s probability distribution, a distributionally robust mp-MILP (DR-mp-MILP) is proposed that considers the worst distribution in a neighborhood of the empirical distribution built by the representative scenarios. The DR-mp-MILP has a max–min form and is reformed as a canonical mp-MILP by duality theory. The proposed method was validated on the modified IEEE nine-bus systems; the parameterized OVFs provide insightful suggestions on storage sizing.
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Vlastos, Dimitris D., Markos Kyritsis, Vasiliki-Alexia Varela, Stephen R. Gulliver, and Afroditi Papaioannou-Spiroulia. "Can a Low-Cost Eye Tracker Assess the Impact of a Valent Stimulus? A Study Replicating the Visual Backward Masking Paradigm." Interacting with Computers 32, no. 2 (March 2020): 132–41. http://dx.doi.org/10.1093/iwc/iwaa010.
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Abstract Capturing affective response to valent stimuli using eye tracking is of interest not only to academic research but also to commercial equipment developers (e.g. car dashboards). In order to investigate whether a low-cost eye tracker can effectively detect participants’ physiological response to negatively valent stimuli, 44 participants aged 19–24 (mean = 24.7, SD = 5.8) were recruited to complete the visual backward masking paradigm in a repeated-measure experimental design. Saccadic duration and pupil sizes were recorded using a lower-end 60-Hz tracker. Data was analysed using a mix of parametric and non-parametric tests. Our results suggest that valence in the form of fearful vs neutral faces has a significant main effect on both saccadic duration [V = 931, P < 0.001, d = 0.96] and pupil size [t(43) = 29.81, P < 0.001, d = 3.91)]. Our findings were further supported by Bayes factor analysis, which showed that saccadic duration data was 24 times more likely to occur, and pupil size measurement data was 89 times more likely, under the alternative hypothesis, showing that differences in valence had a main effect. The combined evidence produced by our Bayesian analysis, the large effect sizes of our frequentist analysis and the significant effect on two separate measurements lead us to suggest that, under the right conditions, low-cost eye trackers can successfully detect changes in saccadic duration and pupil sizes as a result of physiological responses to threat-relevant visual stimuli.
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Anastasia, Chepngetich, Gatakaa Ann Hidah Kinyua, and Muriungi Peter Kinyua. "Position of Wh-Words in Kipsigis Wh-Questions." SMART MOVES JOURNAL IJELLH 8, no. 6 (June 29, 2020): 77–106. http://dx.doi.org/10.24113/ijellh.v8i6.10632.
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The wh-parameter determines whether the wh-expression can be fronted or not. Studies on a number of languages among them English, Shona, Kiitharaka and Chinese have revealed that different languages use different ways to form wh-questions. This paper examines the positions a wh-phrase can occupy in Kipsigis, a southern Nilotic language. A descriptive research design was adopted and a structure generation exercise was used to elicit data from ten competent native speakers of Kipsigis. Data was analysed within the context of the minimalist program developed by Chomsky. The analysis revealed that Kipsigis wh-words can be found in their canonical position, a position termed in-situ. The wh-words can also be moved to the front of the matrix clause. This movement is triggered by a strong focus feature manifested by a focus marker which is always attached to the verb. The wh-words can undergo partial wh-movement where the wh-phrase moves to a position lower than its relevant position. The study also established that adjuncts remain in-situ except for the wh-phrase ‘why’ which can be fronted in addition to being found in-situ. This study contributes towards the understanding of universal and parametric linguistic features in syntactic theory.
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Kholostova, O. V. "On Nonlinear Oscillations of a Near-Autonomous Hamiltonian System in the Case of Two Identical Integer or Half-Integer Frequencies." Nelineinaya Dinamika 17, no. 1 (2021): 77–102. http://dx.doi.org/10.20537/nd210107.
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This paper examines the motion of a time-periodic Hamiltonian system with two degrees of freedom in a neighborhood of trivial equilibrium. It is assumed that the system depends on three parameters, one of which is small; when it has zero value, the system is autonomous. Consideration is given to a set of values of the other two parameters for which, in the autonomous case, two frequencies of small oscillations of the linearized equations of perturbed motion are identical and are integer or half-integer numbers (the case of multiple parametric resonance). It is assumed that the normal form of the quadratic part of the Hamiltonian does not reduce to the sum of squares, i.e., the trivial equilibrium of the system is linearly unstable. Using a number of canonical transformations, the perturbed Hamiltonian of the system is reduced to normal form in terms through degree four in perturbations and up to various degrees in a small parameter (systems of first, second and third approximations). The structure of the regions of stability and instability of trivial equilibrium is investigated, and solutions are obtained to the problems of the existence, number, as well as (linear and nonlinear) stability of the system’s periodic motions analytic in fractional or integer powers of the small parameter. For some cases, conditionally periodic motions of the system are described. As an application, resonant periodic motions of a dynamically symmetric satellite modeled by a rigid body are constructed in a neighborhood of its steady rotation (cylindrical precession) on a weakly elliptic orbit and the problem of their stability is solved.
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Tushev, O. N., A. V. Belyaev, and Yizhou Wang. "Non-Linear Model Dynamics Analysis for Aerospace Engineering Structures Subjected to Non-Steady-State Random Loads." Herald of the Bauman Moscow State Technical University. Series Mechanical Engineering, no. 1 (130) (February 2020): 42–55. http://dx.doi.org/10.18698/0236-3941-2020-1-42-55.
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In aerospace engineering, it is customary to employ stochastic analysis methods at the design stage to investigate how the mechanical system responds to random external forces. This is relevant due to high reliability requirements for spacecraft. We developed a method for probabilistic estimation of the dynamic properties of a structure subjected simultaneously to external (additive) and parametric (multiplicative) vibrations. An ordinary non-linear vector differential equation describes the vibrations in the elastic structure. Non-linear position and velocity properties of kinematic pairs may have cusps and discontinuities. We assume that the probabilistic dispersions of respective phase coordinates are close to the normal distribution of probability density. The initial non-linear vibration equations are statistically linearised. The system of differential equations is not rewritten in the canonical form, which means that it is possible to carry out the probabilistic analysis of the system for any external non-steady-state effect. The fundamental matrix of the linearised system is used to find the expected value vector and the correlation function matrix of the phase coordinate vector. The solution consists of a matrix integro-power series containing linear and quadratic terms. Using the method makes it possible to assess the contribution of each external force component to the total result. We consider an example of a non-linear system responding to a stepwise non-steady-state external influence.
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RACZ, J. P., and J. F. SCOTT. "Parametric instability in a rotating cylinder of gas subject to sinusoidal axial compression. Part 2. Weakly nonlinear theory." Journal of Fluid Mechanics 595 (January 8, 2008): 291–321. http://dx.doi.org/10.1017/s0022112007009226.
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A weakly nonlinear analysis is presented of parametric instability in a rotating cylinder subject to periodic axial compression by small sinusoidal oscillations of one of its ends (‘the piston’). Amplitude equations are derived for the pair of parametrically resonant (primary) inertial modes which were found to arise from linear instability in Part 1. These equations introduce an infinity of geostrophic mode amplitudes, representing a nonlinear modification of the mean flow, for which evolution equations are also derived. Consequences of the total system of equations are investigated for axisymmetric modes. Different possible outcomes are found at large times: (a) a fixed point, representing a saturated state in which the oscillatory toroidal vortices of the primary mode are phase-locked to the piston motion with half its frequency; (b) a limit cycle or chaotic attractor, corresponding to slow-time oscillations of the primary mode; or (c) exponential divergence of the amplitudes to infinity. The latter outcome, a necessary condition for which is derived in the form of a threshold piston amplitude for divergence, invalidates the theory, inducing a gross change in the character of the flow and providing a route out of the weakly nonlinear regime. Non-zero fixed-point branches arise via bifurcations from both sides of the linear neutral curve, where the basic flow changes local stability. The lower-amplitude branch is shown to be unstable, while the upper one may lose local stability, resulting in a Hopf bifurcation to a limit cycle, which can subsequently become aperiodic via a series of further bifurcations. Typically, during the resulting oscillations, whether periodic or not, the perturbation first grows from small amplitude owing to basic-flow instability, then nonlinear detuning of the parametric resonance causes decay back to small amplitude in the second half of the cycle, which then restarts.
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Rogers, F. J., and C. A. Iglesias. "The OPAL opacity Code." Highlights of Astronomy 10 (1995): 573. http://dx.doi.org/10.1017/s1539299600012089.
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The OPAL opacity effort was undertaken in 1985 in response to speculation that the existing opacity data were not of sufficient accuracy to model observed stellar properties. We have taken the view that a completely new code with improved equation of state, atomic physics and line broadening was required. It was apparent that the most computationally intensive part of the calculations would be to obtain the vast amount of atomic data needed for the bound-bound and bound-free absorption cross-sections. To meet this challenge we developed a parametric potential method, that was fast enough to allow on-line calculations, while achieving accuracy comparable to that of the single-configuration Dirac-Fock method. This on-line capability was also chosen to allow flexibility to study the effect of various coupling and data averaging methods. It also makes it easy to study the effect of adding more elements.The OPAL equation of state is based on the many-body statistical mechanics of partially ionized plasmas in the grand canonical ensemble. This is the so-called “physical picture” method. In this approach one works directly with the electrons and nuclei present in the plasma. The effect of the plasma environment on the internal states is obtained directly from the statistical mechanical analysis. A convergent partition function is a natural consequence of this approach.OPAL includes degeneracy and plasma collective effects in the free-free absorption using a screened form of the parametric potentials. Similar corrections to the Thomson scattering are obtained from the method of Boercker (1987). The spectral line broadening for one, two and three electrons ions are obtained from a suite of codes provided by R.W. Lee (1988) that include linear Stark theory. For all other transitions we use Voigt profiles where the Gaussian width is due to Doppler broadening and the Lorentz width is due to the natural width plus fits to the electron impact collision width (Dimitrievic and Konjevic 1980).
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Zhang, Jun. "Divergence Function, Duality, and Convex Analysis." Neural Computation 16, no. 1 (January 1, 2004): 159–95. http://dx.doi.org/10.1162/08997660460734047.
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From a smooth, strictly convex function Φ: Rn → R, a parametric family of divergence function DΦ(α) may be introduced: [Formula: see text] for x, y, ε int dom(Φ) and for α ε R, with DΦ(±1 defined through taking the limit of α. Each member is shown to induce an α-independent Riemannian metric, as well as a pair of dual α-connections, which are generally nonflat, except for α = ±1. In the latter case, D(±1)Φ reduces to the (nonparametric) Bregman divergence, which is representable using and its convex conjugate Φ * and becomes the canonical divergence for dually flat spaces (Amari, 1982, 1985; Amari & Nagaoka, 2000). This formulation based on convex analysis naturally extends the information-geometric interpretation of divergence functions (Eguchi, 1983) to allow the distinction between two different kinds of duality: referential duality (α -α) and representational duality (Φ Φ *). When applied to (not necessarily normalized) probability densities, the concept of conjugated representations of densities is introduced, so that ± α-connections defined on probability densities embody both referential and representational duality and are hence themselves bidual. When restricted to a finite-dimensional affine submanifold, the natural parameters of a certain representation of densities and the expectation parameters under its conjugate representation form biorthogonal coordinates. The alpha representation (indexed by β now, β ε [−1, 1]) is shown to be the only measure-invariant representation. The resulting two-parameter family of divergence functionals D(α, β), (α, β) ε [−1, 1] × [-1, 1] induces identical Fisher information but bidual alpha-connection pairs; it reduces in form to Amari's alpha-divergence family when α =±1 or when β = 1, but to the family of Jensen difference (Rao, 1987) when β = 1.
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Abarca, Sergio F., and Michael T. Montgomery. "Essential Dynamics of Secondary Eyewall Formation." Journal of the Atmospheric Sciences 70, no. 10 (October 1, 2013): 3216–30. http://dx.doi.org/10.1175/jas-d-12-0318.1.
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Abstract The authors conduct an analysis of the dynamics of secondary eyewall formation in two modeling frameworks to obtain a more complete understanding of the phenomenon. The first is a full-physics, three-dimensional mesoscale model in which the authors examine an idealized hurricane simulation that undergoes a canonical eyewall replacement cycle. Analysis of the mesoscale simulation shows that secondary eyewall formation occurs in a conditionally unstable environment, questioning the applicability of moist-neutral viewpoints and related mathematical formulations thereto for studying this process of tropical cyclone intensity change. The analysis offers also new evidence in support of a recent hypothesis that secondary eyewalls form via a progressive boundary layer control of the vortex dynamics in response to a radial broadening of the tangential wind field. The second analysis framework is an axisymmetric, nonlinear, time-dependent, slab boundary layer model with radial diffusion. When this boundary layer model is forced with the aforementioned mesoscale model's radial profile of pressure at the top of the boundary layer, it generates a secondary tangential wind maximum consistent with that from the full-physics, mesoscale simulation. These findings demonstrate that the boundary layer dynamics alone are capable of developing secondary wind maxima without prescribed secondary heat sources and/or invocation of special inertial stability properties of the swirling flow either within or above the boundary layer. Finally, the time-dependent slab model reveals that the simulated secondary wind maximum contracts inward, as secondary eyewalls do in mesoscale models and in nature, pointing to a hitherto unrecognized role of unbalanced dynamics in the eyewall replacement cycle.
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Broughton, Kimberly K., Christopher P. Miller, Caroline Williams, Kristen L. Stupay, and John Y. Kwon. "Can Patient Effort Influence Sensitivity & Specificity of the Gravity Stress View? Assessing the Potential for False Negative Results." Foot & Ankle Orthopaedics 5, no. 4 (October 1, 2020): 2473011420S0014. http://dx.doi.org/10.1177/2473011420s00146.
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Category: Ankle; Trauma Introduction/Purpose: In the setting of apparently isolated distal fibula fractures, the radiographic gravity stress view (GSV) has been validated as a reliable method to determine mortise stability. Based on previous studies demonstrating that plantarflexion can increase the measured medial clear space (MCS), patients are often asked to actively hold their ankle in a neutral position. However, it has not been studied whether dynamic muscle activation in the form of attempted dorsiflexion and/or supination can reduce and realign an unstable mortise. If these efforts can overcome gravity, resultant images could lead to a false negative result and missed diagnosis of instability. The goal of the present investigation is to determine if active effort by the patient can influence MCS measurements in proven unstable bimalleolar-equivalent ankle fractures. Methods: Eighteen consecutive patients with apparently isolated distal fibula fractures (Weber-B type) identified on initial nonweightbearing radiographs were assessed for mortise stability with a standard, unassisted GSV. If the radiograph demonstrated MCS widening > 4 mm, 3 additional views were performed: GSV with an assistant manually maintaining the ankle in a neutral position; GSV with the patient actively dorsiflexing the ankle to the same neutral position; and GSV with the patient actively dorsiflexing and supinating the foot to the same neutral position. All radiographs were digitally obtained and measured using a DICOM measurement tool. The MCS was measured by the senior author (JYK) who was blinded to the nature of the ankle position. Statistical analysis of the data was then conducted. Results: Of the eighteen patients who met inclusion criteria, the mean age was 48.9 years (range: 22-85, SD=18.9). Twelve patients (66%) were female and six (33%) were male. The laterality was evenly split with nine patients presenting with a right ankle injury and nine left ankles. The data was non-parametric; therefore, a Friedman’s test was utilized for analysis between the different MCS measurements per patient. There was no statistically significant difference in the measured MCS in any of the three tested scenarios, χ2(2)=4.261, p=0.119. Only 5 of 18 subjects had any measurable decrease in their MCS when asked to supinate their foot. Of these 5, the maximum reduction was 1.21mm. The remainder of patients had an increase in MCS ranging from 0.1 to 4.0mm. Conclusion: This investigation supports the notion that the gravity stress test is unlikely to yield false negative results when patients attempt to actively maintain a neutral ankle position during imaging. There was a non-significant inverse trend indicating that dynamic effort may in fact further displace the mortise as indicated by an increased MCS in several study participants, rather than reduce it. Thus, one can conclude that despite voluntary effort, patients with bimalleolar-equivalent ankle fractures are unlikely able to overcome the effect of gravity on the unstable mortise.
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Sauquet, E., and C. Catalogne. "Comparison of catchment grouping methods for flow duration curve estimation at ungauged sites in France." Hydrology and Earth System Sciences Discussions 8, no. 2 (April 1, 2011): 3233–69. http://dx.doi.org/10.5194/hessd-8-3233-2011.
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Abstract. The study aims at estimating flow duration curves (FDC) at ungauged sites in France and quantifying the associated uncertainties using a large dataset of 1080 FDCs. The interpolation procedure focuses here on 15 percentiles standardised by the mean annual flow, which is supposed to be known at each site. In particular, this paper discusses the relevance of different catchments grouping procedures on percentiles estimation by regional regression models. First, five parsimonious FDC parametric models were tested to approximate FDCs at gauged sites. The results show that the model based on Empirical Orthogonal Functions (EOF) expansion outperforms the other ones. In this model each FDC is interpreted as a linear combination of regional amplitude functions with weights – the parameters of the model – varying in space. Here, only one amplitude function was found sufficient to fit well most of the observed curves. Thus the considered model requires only two parameters to be estimated at ungauged locations. Second, homogeneous regions were derived according to hydrological response on one hand, and geological, climatic and topographic characteristics on the other hand. Hydrological similarity was assessed through two simple indicators: the concavity index (IC) that represents the shape of the standardized FDC and the seasonality ratio (SR) which is the ratio of summer and winter median flows. These variables were used as homogeneity criteria in three different methods for grouping catchments: (i) according to their membership in one of an a priori French classification into Hydro-Eco-Regions (HERs), (ii) by applying a regression tree clustering and (iii) by using hydrological neighbourhood obtained by canonical correlation analysis. Finally, regression models between physiographic and/or climatic variables and the two parameters of the EOF model were derived considering all the data and thereafter for each group obtained through the tested grouping techniques. Results on percentiles estimation in cross validation show a significant benefit to form homogeneous regions before developing regressions, particularly when grouping methods use hydrogeological information.
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Гольцов, Анатолий Сергеевич, and Hung Manh Tran. "Дослідження цифровий адаптивної системи повороту лопаток направляючого апаратів осьового компресора." Aerospace technic and technology, no. 4sup2 (August 27, 2021): 79–86. http://dx.doi.org/10.32620/aktt.2021.4sup2.10.
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In the simplest cases, P-, PI- and PID-controllers with rigid (unchanged) parameter settings are used to control technological processes. If the mathematical model of the control object contains unknown disturbing influences and parameters that change during the control process, then a digital control system with a learning model should be used. The tasks of control, analysis and modeling of various processes and systems are solved using their mathematical models. The choice of a model is dictated by the conditions of implementation and the requirement of adequacy. The problem of developing control algorithms under uncertainty occupies one of the central places in modern control theory. To solve the arising problems of structural and parametric identification, as a rule, methods, and algorithms of the theory of adaptive control systems are used. The application of the principles of adaptation allows to ensure high accuracy of modeling with a significant change in the dynamic properties of the system under study, to unify individual subsystems and their blocks; reduce the development and debugging time of the system. This article discusses the problem of studying a digital adaptive system for turning the blades of guide apparatus (GA) of an axial compressor of gas turbine engines (GTE). The aim of the study is to increase the efficiency of the control system for turning the blades of the GA using a digital adaptive system. The gas-dynamic stability of the GTE axial compressor under changes in external conditions and engine throttling is provided by air bypass and turning the blades of the first and last compressor stages. The statement of the problem of synthesis of the system of adaptive control of the rotation of the blades of the GA compressor of the gas turbine engine is carried out. A mathematical model of the ACS in the canonical form “model of the system in the state space” and an algorithm for turning the blades of the GA using an adaptive PI-controller have been developed. Simulation modeling of ACS was carried out using the Matlab / Simulink software package. When implementing an adaptive PI-controller, the pressure deviation downstream of the compressor stage from the required value is reduced to 0.4 %.
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Fisher, Kathryn, Maureen Markle-Reid, Jenny Ploeg, Amy Bartholomew, Lauren E. Griffith, Amiram Gafni, Lehana Thabane, and Marie-Lee Yous. "Self-management program versus usual care for community-dwelling older adults with multimorbidity: A pragmatic randomized controlled trial in Ontario, Canada." Journal of Comorbidity 10 (January 1, 2020): 2235042X2096339. http://dx.doi.org/10.1177/2235042x20963390.
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Background: Multimorbidity, the co-existence of 2+ (or 3+) chronic diseases in an individual, is an increasingly common global phenomenon leading to reduced quality of life and functional status, and higher healthcare service use and mortality. There is an urgent need to develop and test new models of care that incorporate the components of multimorbidity interventions recommended by international organizations, including care coordination, interdisciplinary teams, and care plans developed with patients that are tailored to their needs and preferences. Purpose: To determine the effectiveness of a 6-month, community-based, multimorbidity intervention compared to usual home care services for community-dwelling older adults (age 65+ years) with multimorbidity (3+ chronic conditions) that were newly referred to and receiving home care services. Methods: A pragmatic, parallel, two-arm randomized controlled trial evaluated the intervention, which included in-home visits by an interdisciplinary team, personal support worker visits, and monthly case conferences. The study took place in two sites in central Ontario, Canada. Eligible and consenting participants were randomly allocated to the intervention and control group using a 1:1 ratio. The participants, statistician/analyst, and research assistants collecting assessment data were blinded. The primary outcome was the Physical Component Summary (PCS) score of the 12-Item Short-Form health survey (SF-12). Secondary outcomes included the SF-12 Mental Component Summary (MCS) score, Center for Epidemiological Studies of Depression (CESD-10), Generalized Anxiety Disorder (GAD-7), Self-Efficacy for Managing Chronic Disease, and service use and costs. Analysis of covariance (ANCOVA) tested group differences using multiple imputation to address missing data, and non-parametric methods explored service use and cost differences. Results: 59 older adults were randomized into the intervention (n = 30) and control (n = 29) groups. At baseline, groups were similar for the primary outcome and number of chronic conditions (mean of 8.6), but the intervention group had lower mental health status. The intervention was cost neutral and no significant group differences were observed for the primary outcome of PCS from SF-12 (mean difference: −4.94; 95% CI: −12.53 to 2.66; p = 0.20) or secondary outcomes. Conclusion: We evaluated a 6-month, self-management intervention for older adults with multimorbidity. While the intervention was cost neutral in comparison to usual care, it was not found to improve the PCS from SF-12 or secondary health outcomes. Recruitment and retention challenges were significant obstacles limiting our ability to assess intervention effectiveness. Yet, the intervention was grounded in internationally-endorsed recommendations and implemented in a practice setting (home care) viewed as a key upstream resource fostering independence in older adults. These features collectively support the identification of ways to recruit/retain older adults and test alternative implementation strategies for interventions that are based on sound principles of multimorbidity management.
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Chattopadhyay, Maitreyi, Vera A. Stupina, Feng Gao, Christine R. Szarko, Micki M. Kuhlmann, Xuefeng Yuan, Kerong Shi, and Anne E. Simon. "Requirement for Host RNA-Silencing Components and the Virus-Silencing Suppressor when Second-Site Mutations Compensate for Structural Defects in the 3′ Untranslated Region." Journal of Virology 89, no. 22 (September 9, 2015): 11603–18. http://dx.doi.org/10.1128/jvi.01566-15.
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ABSTRACTTurnip crinkle virus (TCV) contains a structured 3′ region with hairpins and pseudoknots that form a complex network of noncanonical RNA:RNA interactions supporting higher-order structure critical for translation and replication. We investigated several second-site mutations in the p38 coat protein open reading frame (ORF) that arose in response to a mutation in the asymmetric loop of a critical 3′ untranslated region (UTR) hairpin that disrupts local higher-order structure. All tested second-site mutations improved accumulation of TCV in conjunction with a partial reversion of the primary mutation (TCV-rev1) but had neutral or a negative effect on wild-type (wt) TCV or TCV with the primary mutation. SHAPE (selective 2′-hydroxylacylation analyzed byprimerextension) structure probing indicated that these second-site mutations reside in an RNA domain that includes most of p38 (domain 2), and evidence for RNA:RNA interactions between domain 2 and 3′UTR-containing domain 1 was found. However, second-site mutations were not compensatory in the absence of p38, which is also the TCV silencing suppressor, or indcl-2/dcl4orago1/ago2backgrounds. One second-site mutation reduced silencing suppressor activity of p38 by altering one of two GW motifs that are required for p38 binding to double-stranded RNAs (dsRNAs) and interaction with RNA-induced silencing complex (RISC)-associated AGO1/AGO2. Another second-site mutation substantially reduced accumulation of TCV-rev1 in the absence of p38 or DCL2/DCL4. We suggest that the second-site mutations in the p38 ORF exert positive effects through a similar downstream mechanism, either by enhancing accumulation of beneficial DCL-produced viral small RNAs that positively regulate the accumulation of TCV-rev1 or by affecting the susceptibility of TCV-rev1 to RISC loaded with viral small RNAs.IMPORTANCEGenomes of positive-strand RNA viruses fold into high-order RNA structures. Viruses with mutations in regions critical for translation and replication often acquire second-site mutations that exert a positive compensatory effect through reestablishment of canonical base pairing with the altered region. In this study, two distal second-site mutations that individually arose in response to a primary mutation in a critical 3′ UTR hairpin in the genomic RNA of turnip crinkle virus did not directly interact with the primary mutation. Although different second-site changes had different attributes, compensation was dependent on the production of the viral p38 silencing suppressor and on the presence of silencing-required DCL and AGO proteins. Our results provide an unexpected connection between a 3′ UTR primary-site mutation proposed to disrupt higher-order structure and the RNA-silencing machinery.
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Moore, David T., Patrik Nygren, Kathleen Molnar, Kathleen Boesze-Battaglia, Joel S. Bennett, and William F. DeGrado. "Protein-Protein and Protein-Lipid Interactions Modulate αIIbβ3 Inside-out Signaling." Blood 114, no. 22 (November 20, 2009): 152. http://dx.doi.org/10.1182/blood.v114.22.152.152.
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Abstract Abstract 152 Integrins are ubiquitously expressed α/β heterodimers that mediate cell-cell and cell-extracellular matrix interactions. The platelet integrin αIIbβ3 binds soluble fibrinogen following platelet activation, an event necessary for the formation of platelet aggregates. Integrins reside on plasma membranes in a highly regulated and dynamic equilibrium between inactive resting states and active ligand binding conformations. An essential feature of this equilibrium is the association and dissociation of integrin transmembrane (TM) and cytoplasmic domains. Thus, when integrins are inactive, the TM and cytoplasmic domains of their α and β subunits are in proximity; the domains separate when integrins assume their active conformations. Agonist-induced activation of αIIbβ3 in platelets (inside-out activation) requires binding of the FERM domain of the cytoskeletal protein talin to highly conserved membrane proximal and distal sequences in the β3 subunit cytoplasmic domain. FERM domain binding to the β3 cytoplasmic domain likely disrupts the αIIbβ3 TM domain-cytoplasmic domain heterodimer. As the β3 cytoplasmic domain exists in close apposition to the inner leaflet of the plasma membrane and the talin FERM domain is known to interact with the negatively-charged phospholipids that are common in eukaryotic membranes, we have investigated the effects of the membrane environment on β3 and talin structure and the talin-β;3 protein-protein interaction that regulates αIIbβ3 activation. A water soluble form of the β3 cytoplasmic domain was expressed, purified, and chemically conjugated to phospholipid bilayers, mimicking the native environment of the αIIb and β3 cytoplasmic domains as they exit the membrane. Using circular dichroism (CD) spectroscopy, the β3 cytoplasmic domain was found to have a significant increase in secondary structure and overall helicity when attached to the bilayer. Similarly, using hydrogen-deuterium exchange (HDX) mass spectrometry, we found that there is an overall decrease in amide backbone flexibility, particularly in the membrane proximal talin-interacting region. We also found significant changes in talin secondary structure in detergents by CD and by limited proteolysis mapping, supporting dramatic conformational changes in talin upon membrane binding. Using isothermal titration calorimetry (ITC) and integrin-conjugated lipid bilayers, we investigated the effects of lipid composition on talin-bilayer and talin-β3 cytoplasmic domain interactions. We found that the talin FERM domain likely has two binding sites for the membrane-conjugated β3 cytoplasmic domain, one in the canonical F3 subdomain and a second that depends on the F2 subdomain. Moreover, the talin head domain does not bind to β3 on neutral bilayers and requires a significant excess of phosphatidylserine (PS) relative to β3 to allow saturation. Interestingly phosphatidylinositol (4, 5)-bisphosphate containing bilayers have significantly higher affinity and mitigate the need for excess PS. Our results point toward a model in which β3 cytoplasmic domain structure is dependent on the lipid environment and its interaction with talin. Thus, αIIbβ3 activation is significantly regulated by lipid which may play a role in constraining αIIbβ3 activation by talin in the crowded platelet intracellular environment. Disclosures: No relevant conflicts of interest to declare.
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Anderson, Cary. "Quantifying Emotion: Survey Methods and Sentiment Analysis in Cartographic Design Research." Abstracts of the ICA 1 (July 15, 2019): 1–2. http://dx.doi.org/10.5194/ica-abs-1-8-2019.
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<p><strong>Abstract.</strong> Despite the strong connection between art and emotion &ndash; and cartography’s position as both an art and a science &ndash; only recently has there been a strong call for cartographers to partake in research related to maps and emotion (Griffin and McQuoid 2012). Such research can typically be classified into one of three categories: (1) maps of emotions (i.e., visualizations of spaces as happy or fearful), (2) maps as tools for the collection of emotive data, and (3) affective responses to maps (Griffin and McQuoid). Of these, the first two have been the primary focus of most recent research in emotive cartography; this research has benefited greatly from the proliferation of participatory web-based technologies such as social media, smart phones, and fitness activity trackers.</p><p>The third category of affective map research &ndash; the study of emotional responses to maps &ndash; has received less attention, though some notable work (e.g., Fabrikant et al. 2012) has highlighted its importance. We suggest that such research on affective responses to maps might also benefit from an increased reliance on web-based data collection techniques. There has been, for example, a recent increase in the use of online crowdsourcing platforms such as Amazon Mechanical Turk for cartographic and related visual perception research (e.g., Heer and Bostock 2010; Limpisathian 2017). Such platforms decrease the cost of participant recruitment and survey dissemination, while facilitating easier testing of samples outside of the traditional undergraduate student subject pool.</p><p>Given the inherently personal and subjective nature of emotions, the use of crowdsourced samples to measure affective responses to maps poses an interesting dilemma. How might cartographers assess the emotive nature of maps and mapping products via participant samples that are both geographically dispersed and impersonal by design? As a case study, we present a user study recently conducted to measure participant responses to <i>affectively-congruent</i> (vs. incongruent) chorochromatic maps. By <i>affectively-congruent</i>, we mean maps with data topics whose emotive content is in harmony with the emotive nature of the colour scheme. For example, a thematic map about homicide with dull, muted, colours would be considered affectively-congruent, while one with bright, highly-saturated colours would be considered incongruent (Figure 1).</p><p>In this work, we discuss two contrasting methods for collecting and analysing emotive participant interpretations of these maps. First, with closed-ended survey questions, wherein study participants are asked to rate how much a map exhibits a type of emotion (e.g., positive). In our study, we used a modified 7-point version of the <i>Affective Slider</i>, a tool developed by Betella and Verschure (2016) for measuring emotion in web-based surveys. Thus, due to our 7-point scale, participants classified their rating of a map’s emotive content into one of 7 ranked categories. We use a between-subjects design and analysed participant responses using non-parametric tests.</p><p>The second method we discuss for analysing affective response to maps is the collection of free-form responses from survey respondents, followed by the classification of these responses using sentiment analysis. In our study, we asked participants to provide three words they would use to describe each map. We then categorized these responses as either positive, negative, or neutral using the <i>ParallelDots</i> Sentiment Analysis API. Thus, we did not ask participants to classify a map’s level of emotion specifically, but rather collected their more instinctive responses and categorized them later using text classification algorithms.</p><p>Following a discussion of the respective merits and drawbacks of these methods, we discuss how the selection of one of these contrasting approaches might influence affective cartographic research results. For example, in our study, while the Affective Slider proved a more efficient tool for analysing between-subject variance in emotive rankings of maps, sentiment analysis of free-form responses facilitated better analysis of within-subject variance. One participant, for example, listed both “exciting” and “depressing” in response to a single affectively-incongruent map, highlighting the confusion that can be triggered by a map with an incongruent design.</p><p>In closing, we discuss the multitude of challenges introduced by these methods &ndash; including the false precision sometimes provided by fine-grained survey scales and complex algorithms, and the paradoxical nature of personal data collection via anonymous participants. But despite these challenges we propose that crowdsourced surveys show strong promise for quantitative affective mapping research: future work is likely to result in new, exciting insights into user’s affective responses to maps and mapping products.</p>
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Portalone, Gustavo. "6-Methyluracil: a redetermination of polymorph (II)." IUCrData 4, no. 6 (June 21, 2019). http://dx.doi.org/10.1107/s2414314619008617.
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6-Methyluracil, C5H6N2O2, exists in two crystalline phases: form (I), monoclinic, space group P21/c [Reck et al. (1988). Acta Cryst. A44, 417–421] and form (II), monoclinic, space group C2/c [Leonidov et al. (1993). Russ. J. Phys. Chem. 67, 2220–2223]. The structure of polymorph (II) has been redetermined providing a significant increase in the precision of the derived geometric parameters. In the crystal, molecules form ribbons approximately running parallel to the c-axis direction through N—H...O hydrogen bonds. The radical differences observed between the crystal packing of the two polymorphs may be responsible in form (II) for an increase in the contribution of the polar canonical forms C—(O−)=N—H+ relative to the neutral canonical form C(=O)—N—H induced by hydrogen-bonding interactions.
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Hartnoll, Sean A., Gary T. Horowitz, Jorrit Kruthoff, and Jorge E. Santos. "Gravitational duals to the grand canonical ensemble abhor Cauchy horizons." Journal of High Energy Physics 2020, no. 10 (October 2020). http://dx.doi.org/10.1007/jhep10(2020)102.
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Abstract The gravitational dual to the grand canonical ensemble of a large N holographic theory is a charged black hole. These spacetimes — for example Reissner- Nordström-AdS — can have Cauchy horizons that render the classical gravitational dynamics of the black hole interior incomplete. We show that a (spatially uniform) deformation of the CFT by a neutral scalar operator generically leads to a black hole with no inner horizon. There is instead a spacelike Kasner singularity in the interior. For relevant deformations, Cauchy horizons never form. For certain irrelevant deformations, Cauchy horizons can exist at one specific temperature. We show that the scalar field triggers a rapid collapse of the Einstein-Rosen bridge at the would-be Cauchy horizon. Finally, we make some observations on the interior of charged dilatonic black holes where the Kasner exponent at the singularity exhibits an attractor mechanism in the low temperature limit.
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PARROW, JOACHIM, JOHANNES BORGSTRÖM, PALLE RAABJERG, and JOHANNES ÅMAN POHJOLA. "Higher-order psi-calculi." Mathematical Structures in Computer Science 24, no. 2 (June 24, 2013). http://dx.doi.org/10.1017/s0960129513000170.
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In earlier work we explored the expressiveness and algebraic theory Psi-calculi, which form a parametric framework for extensions of the pi-calculus. In the current paper we consider higher-order psi-calculi through a technically surprisingly simple extension of the framework, and show how an arbitrary psi-calculus can be lifted to its higher-order counterpart in a canonical way. We illustrate this with examples and establish an algebraic theory of higher-order psi-calculi. The formal results are obtained by extending our proof repositories in Isabelle/Nominal.
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Donoghoe, Mark W., and Ian C. Marschner. "Flexible Regression Models for Rate Differences, Risk Differences and Relative Risks." International Journal of Biostatistics 11, no. 1 (January 1, 2015). http://dx.doi.org/10.1515/ijb-2014-0044.
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AbstractGeneralized additive models (GAMs) based on the binomial and Poisson distributions can be used to provide flexible semi-parametric modelling of binary and count outcomes. When used with the canonical link function, these GAMs provide semi-parametrically adjusted odds ratios and rate ratios. For adjustment of other effect measures, including rate differences, risk differences and relative risks, non-canonical link functions must be used together with a constrained parameter space. However, the algorithms used to fit these models typically rely on a form of the iteratively reweighted least squares algorithm, which can be numerically unstable when a constrained non-canonical model is used. We describe an application of a combinatorial EM algorithm to fit identity link Poisson, identity link binomial and log link binomial GAMs in order to estimate semi-parametrically adjusted rate differences, risk differences and relative risks. Using smooth regression functions based on B-splines, the method provides stable convergence to the maximum likelihood estimates, and it ensures that the estimates always remain within the parameter space. It is also straightforward to apply a monotonicity constraint to the smooth regression functions. We illustrate the method using data from a clinical trial in heart attack patients.