An empirical investigation of hypersexuality

The aim of this study was to investigate the nature of hypersexuality and the personality factors associated with the desire for and experience of high frequency sexual behavior. Participants in the study were 69 male and 93 female university students. Respondents reported on their desire for and experience of masturbation, oral sex, sexual intercourse, pornography, indecent phone calls or letters, prostitution, exhibitionism, voyeurism, as well as providing self-report measures which evaluated their levels of state and trait anxiety, depression, obsessive and compulsive symptoms and fear of intimacy. The results demonstrated that subjects who engaged in high-frequency voyeurism were more depressed than low-frequency voyeurs. Respondents in the high-frequency sexual deviant desire and behavior groups appeared to have more obsessive-compulsive symptoms in comparison to the low-frequency deviant sexual behavior and desire groups. Increased psychopathology was not associated with high-frequency non-deviant sexual behaviors and desires. This finding raised the question of whether labels such as sexual compulsion and addiction are merely pathologizing illegal sexual behavior

Windsurfing : an extreme form of material and embodied interaction?

This paper makes reference to the development of water based board sports in the world of adventure or action games. With a specific focus on windsurfing, we use Parlebas (1999) and Warnier's (2001) theoretical interests in the praxaeology of physical learning as well as Mauss' (1935) work on techniques of the body. We also consider the implications of Csikzentimihalyi's notion of flow (1975). We argue that windsurfing equipment should not merely be seen as protection but rather as status objects through which extreme lifestyles are embodied and embodying

Courant-Dorfman algebras and their cohomology

We introduce a new type of algebra, the Courant-Dorfman algebra. These are to Courant algebroids what Lie-Rinehart algebras are to Lie algebroids, or Poisson algebras to Poisson manifolds. We work with arbitrary rings and modules, without any regularity, finiteness or non-degeneracy assumptions. To each Courant-Dorfman algebra (\R,\E) we associate a differential graded algebra \C(\E,\R) in a functorial way by means of explicit formulas. We describe two canonical filtrations on \C(\E,\R), and derive an analogue of the Cartan relations for derivations of \C(\E,\R); we classify central extensions of \E in terms of H^2(\E,\R) and study the canonical cocycle \Theta\in\C^3(\E,\R) whose class $[\Theta]$ obstructs re-scalings of the Courant-Dorfman structure. In the nondegenerate case, we also explicitly describe the Poisson bracket on \C(\E,\R); for Courant-Dorfman algebras associated to Courant algebroids over finite-dimensional smooth manifolds, we prove that the Poisson dg algebra \C(\E,\R) is isomorphic to the one constructed in \cite{Roy4-GrSymp} using graded manifolds.Comment: Corrected formulas for the brackets in Examples 2.27, 2.28 and 2.29. The corrections do not affect the exposition in any wa

The City: Art and the Urban Environment

The City: Art and the Urban Environment is the fifth annual exhibition curated by students enrolled in the Art History Methods class. This exhibition draws on the students’ newly developed expertise in art-historical methodologies and provides an opportunity for sustained research and an engaged curatorial experience. Working with a selection of paintings, prints, and photographs, students Angelique Acevedo ’19, Sidney Caccioppoli ’21, Abigail Coakley ’20, Chris Condon ’18, Alyssa DiMaria ’19, Carolyn Hauk ’21, Lucas Kiesel ’20, Noa Leibson ’20, Erin O’Brien ’19, Elise Quick ’21, Sara Rinehart ’19, and Emily Roush ’21 carefully consider depictions of the urban environment in relation to significant social, economic, artistic, and aesthetic developments. [excerpt]https://cupola.gettysburg.edu/artcatalogs/1029/thumbnail.jp

Circumstellar Na I and Ca II lines in type IIP supernovae and SN 1998S

We study a possibility of detection of circumstellar absorption lines of Na I D$_{1,2}$ and Ca II H,K in spectra of type IIP supernovae at the photospheric epoch. The modelling shows that the circumstellar lines of Na I doublet will not be seen in type IIP supernovae for moderate wind density, e.g., characteristic of SN 1999em, whereas rather pronounced Ca II lines with P Cygni profile should be detectable. A similar model is used to describe Na I and Ca II circumstellar lines seen in SN 1998S, type IIL with a dense wind. We show that line intensities in this supernova are reproduced, if one assumes an ultraviolet excess, which is caused primarily by the comptonization of supernova radiation in the shock wave.Comment: To be published in Astronomy Letter

Morita base change in Hopf-cyclic (co)homology

In this paper, we establish the invariance of cyclic (co)homology of left Hopf algebroids under the change of Morita equivalent base algebras. The classical result on Morita invariance for cyclic homology of associative algebras appears as a special example of this theory. In our main application we consider the Morita equivalence between the algebra of complex-valued smooth functions on the classical 2-torus and the coordinate algebra of the noncommutative 2-torus with rational parameter. We then construct a Morita base change left Hopf algebroid over this noncommutative 2-torus and show that its cyclic (co)homology can be computed by means of the homology of the Lie algebroid of vector fields on the classical 2-torus.Comment: Final version to appear in Lett. Math. Phy

Evaluation and Improvement of Control Vector Iteration Procedures for Optimal Control

An alternate graphical representation of linear, time-invariant, multi-input, multi-output (MIMO) system dynamics is proposed that is highly suited for exploring the influence of closedloop system parameters. The development is based on the adjustment of a scalar forward gain multiplying a cascaded multivariable controller/plant embedded in an output feedback configuration. By tracking the closed-loop eigenvalues as explicit functions of gain, it is possible to visualize the multivariable root loci in a set of "gain plots" consisting of two graphs: (i) magnitude of system eigenvalues versus gain and (ii) argument (angle) of system eigenvalues versus gain. The gain plots offer an alternative perspective of the standard MIMO root locus plot by depicting unambiguously the polar coordinates of each eigenvalue in the complex plane. Two example problems demonstrate the utility of gain plots for interpreting closed-loop multivariable system behavior. Introduction Since their introduction, classical control tools have been popular for analysis and design of single-input, single-output (SISO) systems. These tools may be viewed as specialized versions of more general methods that are applicable to multiinput, multi-output (MIMO) systems. Although modern "statespace" control techniques (relying on dynamic models of internal structure) are generally promoted as the predominant tools for multivariable system analysis, the classical control extensions offer several advantages, including requiring only an input-output map and providing direct insight into stability, performance, and robustness of MIMO systems. The understanding generated by these graphically based methods for the analysis and design of MIMO systems is a prime motivator of this research. An early graphical method for investigating the stability of linear, time-invariant (LTI) SISO systems was developed by ference transfer function matrix ([I + G(s)] where G(s) is the open-loop system transfer function matrix, rather than just 1 + g(s) for the SISO case where g{s) is the system transfer function). Despite the complication, significant research has supported the MIMO Nyquist extension for assessment of multivariable system stability and robustness The Bode plots Although promoted as an SISO tool, Evans root locus method To aid the controls engineer in extracting more information from the multivariable Evans root locus plot, we propose a set of "gain plots" that provide a direct and unique window into the stability, performance, and robustness of LTI MIMO systems. A conceptual framework motivating the gain plots and a discussion of their applicability to SISO systems has been presented previously Multivariable Eigenvalue Description Basic MIMO Concepts. A LTI MIMO plant can be represented in the standard state-space form as where state vector x p is length n, input vector u is length m, and output vector y is length m. Matrices A p , B p , C p , and D p are the system matrix, the control influence matrix, the output matrix, and the feed-forward matrix, respectively, of the plant with appropriate dimensions. The plant input-output dynamics are governed by the transfer function matrix, G p (s), GpW^CplsI-ApV'Bp + Vp (3) The system is embedded in the closed-loop configuration shown in Fig. 1 Ml MO closed-loop negative feedback configuration where A c , B c , C c , and D c are the controller matrices representing its internal structure, in similarity to Eqs. In the MIMO root locus plot, the migration of the eigenvalues of G*(5) in the complex plane is graphed for 0 < k < oo. (By equating the determinant of [I + kG p (s)G c (s)] to zero, the MIMO generalization of the SISO characteristic equation The presence of the determinant is the major challenge in generalizing the SISO root locus sketching rules to MIMO systems and complicates the root locus plot.) The closed-loop system dynamics can alternatively be cast in state-space form in terms of state vector r . The closed-loop system matrix then becomes where The eigenvalues of the closed-loop system,5 = X; = eig(A') (i = 1,2, . . . , «), may be computed numerically from Eq. (6). In the examples, the loci of the eigenvalues are calculated as k is monotonically increased from zero. High Gain Behavior. As the gain is swept from zero to infinity, the closed-loop eigenvalues trace out "root loci" in the complex plane. At zero gain, the poles of the closed-loop system are the open-loop eigenvalues. At infinite gain some of the eigenvalues approach finite transmission zeros, defined to be those values of s that satisfy the generalized eigenvalue problem. In the absence of pole/zero cancellation, the finite transmission zeros are the roots of the determinants of G p (s) and G c (s). Algorithms have been developed for efficient and accurate computation of transmission zeros The eigenvalues can be considered as always migrating from the open-loop poles to their matching transmission zeros MIMO Gain Plots. Just as the Bode plots embellish the information of the Nyquist diagram by exposing frequency explicitly in a set of magnitude versus frequency and angle (phase) versus frequency plots, it follows that a pair of gain plots (Kurfess and Nagurka, 1991) can enhance the standard root locus plot. As the gain-domain analog of the frequencydomain Bode plots, the gain plots explicitly depict the eigenvalue magnitude versus gain in a magnitude gain plot, and the eigenvalue angle versus gain in an angle gain plot. In similarity to the Bode plots, the magnitude gain plot employs a log-log scale whereas the angle gain plot uses a semi-log scale (with the logarithms being base 10). Although gain is selected as the variable of interest in the gain plots, it should be noted that any scalar parameter may be used in the geometric analysis, leading to the more generic idea of parametric plots. Gain plots can be drawn for both SISO and MIMO systems. In MIMO systems it is assumed that a single scalar gain amplifies all controller/plant inputs. For such systems, inspection of the magnitude and angle gain plots enables one to uniquely identify locus branches as a function of gain. As such, gain plots are a natural complement to multivariable root locus plots, where uncharacteristically confusing eigenvalue trajectories can result from being drawn in a single complex plane. Furthermore, it can be shown that the slopes of the lines in the gain plots are proportionally related to the root sensitivity function (Kurfess and Nagurka, 1992). MIMO Examples This section presents two multivariable examples. The first example introduces the concept of the gain plots and demonstrates the insight they offer by "unwrapping" the multivariable root locus and exposing unambiguous behavior. The second example highlights the power of the gain plots in revealing typical multivariable properties, such as high gain Butterworth patterns. Example 1: Coupled MIMO Example. The forward loop dynamics of this example are given by the transfer function matrix (Equation The gain plots presented in The gain plots highlight several other important features. For example, they show that the gains corresponding to the complex conjugate eigenvalue pairs break into the real axis and then proceed toward ± oo. Complex conjugate eigenvalues are shown as symmetric lines about either the 180 or 0 deg line with equal magnitudes. Purely real eigenvalues possess equal angles (180 or 0 deg) but distinct magnitudes. This behavior is demonstrated in The rates at which the eigenvalues increase toward infinite magnitude is seen in the magnitude gain plot of From Conclusions In typical MIMO root locus plots trajectories may be camouflaged as branches may overlap. Gain plots are promoted as a means to "untangle" MIMO eigenvalue trajectories. The major enhancement is the visualization of eigenvalue trajectories as an explicit function of gain, assumed here to be the same static gain applied to all error signals. The perspective presented in this note is intended to complement the many tools available to the controls engineer. In particular, for MIMO systems the gain plots provide: (/) a unique description of eigenvalues and their trajectories as a parameter, such as gain, is varied, (ii) a geometric depiction of the Riemann sheets at high gain, and (Hi) a rich educational tool for conducting parametric analyses of multivariable systems. Research efforts, currently underway, may shed additional light on gain plots for multivariable systems. In addition, work by MacFarlane and'Postlethwaite (1977 and In conclusion, gain plots enrich the multivarible root locus plot in much the same way that singular value frequency plots are an alternate and extended presentation of the multivariable Nyquist diagram. Their use in conjunction with the multivariable root locus provides a valuable geometric perspective on multivariable system behavior. Acknowledgment The authors wish to thank Mr. Ssu-Kuei Wang for his help, and for his earnest enthusiasm of gain plots for studying multivariable and optimal systems

From Atiyah Classes to Homotopy Leibniz Algebras

A celebrated theorem of Kapranov states that the Atiyah class of the tangent bundle of a complex manifold $X$ makes $T_X[-1]$ into a Lie algebra object in $D^+(X)$, the bounded below derived category of coherent sheaves on $X$. Furthermore Kapranov proved that, for a K\"ahler manifold $X$, the Dolbeault resolution $\Omega^{\bullet-1}(T_X^{1,0})$ of $T_X[-1]$ is an $L_\infty$ algebra. In this paper, we prove that Kapranov's theorem holds in much wider generality for vector bundles over Lie pairs. Given a Lie pair $(L,A)$, i.e. a Lie algebroid $L$ together with a Lie subalgebroid $A$, we define the Atiyah class $\alpha_E$ of an $A$-module $E$ (relative to $L$) as the obstruction to the existence of an $A$-compatible $L$-connection on $E$. We prove that the Atiyah classes $\alpha_{L/A}$ and $\alpha_E$ respectively make $L/A[-1]$ and $E[-1]$ into a Lie algebra and a Lie algebra module in the bounded below derived category $D^+(\mathcal{A})$, where $\mathcal{A}$ is the abelian category of left $\mathcal{U}(A)$-modules and $\mathcal{U}(A)$ is the universal enveloping algebra of $A$. Moreover, we produce a homotopy Leibniz algebra and a homotopy Leibniz module stemming from the Atiyah classes of $L/A$ and $E$, and inducing the aforesaid Lie structures in $D^+(\mathcal{A})$.Comment: 36 page

Algorithmic Complexity for Short Binary Strings Applied to Psychology: A Primer

Since human randomness production has been studied and widely used to assess executive functions (especially inhibition), many measures have been suggested to assess the degree to which a sequence is random-like. However, each of them focuses on one feature of randomness, leading authors to have to use multiple measures. Here we describe and advocate for the use of the accepted universal measure for randomness based on algorithmic complexity, by means of a novel previously presented technique using the the definition of algorithmic probability. A re-analysis of the classical Radio Zenith data in the light of the proposed measure and methodology is provided as a study case of an application.Comment: To appear in Behavior Research Method