Linearized theory of conical supersonic flow with application to triangular wings /

Loose-leaf.

The non-violence of love:a Hildebrand-Girard encounter

If love is a social as well as a personal reality, it could be fruitful to compare Von Hildebrand’s understanding of love and desire with that of cultural anthropologist René Girard. Girard depicts love and desire as a triangular process which arises from imitation, rather than the result of auto-generative affection. In this sense, Girardian theory would seem to convict Von Hildebrand of what is called the romantic lie wherein desire is thought to arise through the mutual appreciation of two subjects. However, in The Nature of Love Von Hildebrand shows his awareness of the possibility that love can be awakened by imitation. Moreover, the lack of a sufficient reason in Girardian theory for avoiding violence can be answered by turning to Von Hildebrand’s appreciation of the ontological basis for desire.

Half-Filled Layered Organic Superconductors and the Resonating-Valence-Bond Theory of the Hubbard-Heisenberg Model

We present a resonating-valence-bond theory of superconductivity for the Hubbard-Heisenberg model on an anisotropic triangular lattice. Our calculations are consistent with the observed phase diagram of the half-filled layered organic superconductors, such as the beta, beta('), kappa, and lambda phases of (BEDT-TTF)(2)X [bis(ethylenedithio)tetrathiafulvalene] and (BETS)(2)X [bis(ethylenedithio)tetraselenafulvalene]. We find a first order transition from a Mott insulator to a d(x)(2)-y(2) superconductor with a small superfluid stiffness and a pseudogap with d(x)(2)-y(2) symmetry.

First-principles electronic theory of non-collinear magnetic order in transition-metal nanowires

The structural, electronic and magnetic properties of one-dimensional 3d transition-metal (TM) monoatomic chains having linear, zigzag and ladder geometries are investigated in the frame-work of first-principles density-functional theory. The stability of long-range magnetic order along the nanowires is determined by computing the corresponding frozen-magnon dispersion relations as a function of the 'spin-wave' vector q. First, we show that the ground-state magnetic orders of V, Mn and Fe linear chains at the equilibrium interatomic distances are non-collinear (NC) spin-density waves (SDWs) with characteristic equilibrium wave vectors q that depend on the composition and interatomic distance. The electronic and magnetic properties of these novel spin-spiral structures are discussed from a local perspective by analyzing the spin-polarized electronic densities of states, the local magnetic moments and the spin-density distributions for representative values q. Second, we investigate the stability of NC spin arrangements in Fe zigzag chains and ladders. We find that the non-collinear SDWs are remarkably stable in the biatomic chains (square ladder), whereas ferromagnetic order (q =0) dominates in zigzag chains (triangular ladders). The different magnetic structures are interpreted in terms of the corresponding effective exchange interactions J(ij) between the local magnetic moments μ(i) and μ(j) at atoms i and j. The effective couplings are derived by fitting a classical Heisenberg model to the ab initio magnon dispersion relations. In addition they are analyzed in the framework of general magnetic phase diagrams having arbitrary first, second, and third nearest-neighbor (NN) interactions J(ij). The effect of external electric fields (EFs) on the stability of NC magnetic order has been quantified for representative monoatomic free-standing and deposited chains. We find that an external EF, which is applied perpendicular to the chains, favors non-collinear order in V chains, whereas it stabilizes the ferromagnetic (FM) order in Fe chains. Moreover, our calculations reveal a change in the magnetic order of V chains deposited on the Cu(110) surface in the presence of external EFs. In this case the NC spiral order, which was unstable in the absence of EF, becomes the most favorable one when perpendicular fields of the order of 0.1 V/Å are applied. As a final application of the theory we study the magnetic interactions within monoatomic TM chains deposited on graphene sheets. One observes that even weak chain substrate hybridizations can modify the magnetic order. Mn and Fe chains show incommensurable NC spin configurations. Remarkably, V chains show a transition from a spiral magnetic order in the freestanding geometry to FM order when they are deposited on a graphene sheet. Some TM-terminated zigzag graphene-nanoribbons, for example V and Fe terminated nanoribbons, also show NC spin configurations. Finally, the magnetic anisotropy energies (MAEs) of TM chains on graphene are investigated. It is shown that Co and Fe chains exhibit significant MAEs and orbital magnetic moments with in-plane easy magnetization axis. The remarkable changes in the magnetic properties of chains on graphene are correlated to charge transfers from the TMs to NN carbon atoms. Goals and limitations of this study and the resulting perspectives of future investigations are discussed.

Sexual initiation of U.S. Latino and Colombian high school students: Toward a new theory of adolescent sexuality and implications for sexual health prevention and promotion

The general research question for this dissertation was: do the data on adolescent sexual experiences and sexual initiation support the explicit or implicit adolescent sexuality theories informing the sexual health interventions currently designed for youth? To respond to this inquiry, three different studies were conducted. The first study included a conceptual and historical analysis of the notion of adolescence introduced by Stanley Hall, the development of an alternative model based on a positive view of adolescent sexuality, and the rationale for introducing to adolescent sexual health prevention programs the new definitions of sexual health and the social determinants of health approach. The second one was a quantitative study aimed at surveying not only adolescents' risky sexual behaviors but also sexual experiences associated with desire/pleasure which have been systematically neglected when investigating the sexual and reproductive health of the youth. This study was conducted with a representative sample of the adolescents attending public high schools in the State of Caldas in the Republic of Colombia. The third study was a qualitative analysis of 22 interviews conducted with male and female U.S. Latino adolescents on the reasons for having had or having not had vaginal sex. The more relevant results were: most current adolescent sexual health prevention programs are still framed in a negative approach to adolescent sexuality developed a century ago by Stanley Hall and Sigmund Freud which do not accept the adolescent sexual experience and propose its sublimation. In contrast, the Colombian study indicates that, although there are gender differences, adolescence is for males and females a normal period of sexual initiation not limited to coital activity, in which sexual desire/pleasure is strongly associated with sexual behavior. By the same token, the study about the reasons for having had or not had initiated heterosexual intercourse indicated that curiosity, sexual desire/pleasure, and love are basic motivations for deciding to have vaginal sexual intercourse for the first time and that during adolescence, young women and men reach the cognitive development necessary for taking conscious decisions about their sexual acts. The findings underline the importance of asking pertinent questions about desire/pleasure when studying adolescent sexuality and adopting an evidence-based approach to sexual health interventions.^

On the opportunism-independent theory of the firm

Previous developments in the opportunism-independent theory of the firm are either restricted to special cases or are derived from the capabilities or resource-based perspective. However, a more general opportunism-independent approach can be developed, based on the work of Demsetz and Coase, which is nevertheless contractual in nature. This depends on 'direction', that is, deriving economic value by permitting one set of actors to direct the activities of another, and of non-human factors of production. Direction helps to explain not only firm boundaries and organisation, but also the existence of firms, without appealing to opportunism or moral hazard. The paper also considers the extent to which it is meaningful to speak of 'contractual' theories in the absence of opportunism, and whether this analysis can be extended beyond the employment contract to encompass ownership of assets by the firm. © The Author 2005. Published by Oxford University Press on behalf of the Cambridge Political Economy Society. All rights reserved.

Opportunism, hold-up and the (contractual) theory of the firm

This paper considers the role of opportunism in three contractual theories of the firm: rent-seeking theory, property rights theory, and agency theory. In each case I examine whether it is possible to have a functioning contractual theory of the firm without recourse to opportunism. Without opportunism firms may still exist as a result of issues arising from (incomplete) contracting. Far from posing a problem for the theory of the firm, questioning the role of opportunism and the ubiquity of the hold-up problem helps us understand more about the purpose and functions of contracts which go beyond mere incentive alignment.

Atomic Charge Transfer-counter Polarization Effects Determine Infrared Ch Intensities Of Hydrocarbons: A Quantum Theory Of Atoms In Molecules Model.

Atomic charge transfer-counter polarization effects determine most of the infrared fundamental CH intensities of simple hydrocarbons, methane, ethylene, ethane, propyne, cyclopropane and allene. The quantum theory of atoms in molecules/charge-charge flux-dipole flux model predicted the values of 30 CH intensities ranging from 0 to 123 km mol(-1) with a root mean square (rms) error of only 4.2 km mol(-1) without including a specific equilibrium atomic charge term. Sums of the contributions from terms involving charge flux and/or dipole flux averaged 20.3 km mol(-1), about ten times larger than the average charge contribution of 2.0 km mol(-1). The only notable exceptions are the CH stretching and bending intensities of acetylene and two of the propyne vibrations for hydrogens bound to sp hybridized carbon atoms. Calculations were carried out at four quantum levels, MP2/6-311++G(3d,3p), MP2/cc-pVTZ, QCISD/6-311++G(3d,3p) and QCISD/cc-pVTZ. The results calculated at the QCISD level are the most accurate among the four with root mean square errors of 4.7 and 5.0 km mol(-1) for the 6-311++G(3d,3p) and cc-pVTZ basis sets. These values are close to the estimated aggregate experimental error of the hydrocarbon intensities, 4.0 km mol(-1). The atomic charge transfer-counter polarization effect is much larger than the charge effect for the results of all four quantum levels. Charge transfer-counter polarization effects are expected to also be important in vibrations of more polar molecules for which equilibrium charge contributions can be large.

Beliefs Related To Adherence To Oral Antidiabetic Treatment According To The Theory Of Planned Behavior.

to identify salient behavioral, normative, control and self-efficacy beliefs related to the behavior of adherence to oral antidiabetic agents, using the Theory of Planned Behavior. cross-sectional, exploratory study with 17 diabetic patients in chronic use of oral antidiabetic medication and in outpatient follow-up. Individual interviews were recorded, transcribed and content-analyzed using pre-established categories. behavioral beliefs concerning advantages and disadvantages of adhering to medication emerged, such as the possibility of avoiding complications from diabetes, preventing or delaying the use of insulin, and a perception of side effects. The children of patients and physicians are seen as important social references who influence medication adherence. The factors that facilitate adherence include access to free-of-cost medication and taking medications associated with temporal markers. On the other hand, a complex therapeutic regimen was considered a factor that hinders adherence. Understanding how to use medication and forgetfulness impact the perception of patients regarding their ability to adhere to oral antidiabetic agents. medication adherence is a complex behavior permeated by behavioral, normative, control and self-efficacy beliefs that should be taken into account when assessing determinants of behavior.

Pulsar binary systems in a nonsymmetric theory of gravitation II. Dipole radiation

This paper deals with the emission of gravitational radiation in the context of a previously studied metric nonsymmetric theory of gravitation. The part coming from the symmetric part of the metric coincides with the mass quadrupole moment result of general relativity. The one associated to the antisymmetric part of the metric involves the dipole moment of the fermionic charge of the system. The results are applied to binary star systems and the decrease of the period of the elliptical motion is calculated.

Nonexistence of regular stationary solution in a metric nonsymmetric theory of gravitation

It is proven that the field equations of a previously studied metric nonsymmetric theory of gravitation do not admit any non-singular stationary solution which represents a field of non-vanishing total mass and non-vanishing total fermionic charge.

Theory of small-signal ac response of a dielectric liquid containing two groups of ions

The analysis of Macdonald for electrolytes is generalized to the case in which two groups of ions are present. We assume that the electrolyte can be considered as a dispersion of ions in a dielectric liquid, and that the ionic recombination can be neglected. We present the differential equations governing the ionic redistribution when the liquid is subjected to an external electric field, describing the simultaneous diffusion of the two groups of ions in the presence of their own space charge fields. We investigate the influence of the ions on the impedance spectroscopy of an electrolytic cell. In the analysis, we assume that each group of ions have equal mobility, the electrodes perfectly block and that the adsorption phenomena can be neglected. In this framework, it is shown that the real part of the electrical impedance of the cell has a frequency dependence presenting two plateaux, related to a type of ambipolar and free diffusion coefficients. The importance of the considered problem on the ionic characterization performed by means of the impedance spectroscopy technique was discussed. (c) 2008 American Institute of Physics.

Theory of near-gap second harmonic generation in centrosymmetric magnetic semiconductors: Europium chalcogenides

Second harmonic generation is strictly forbidden in centrosymmetric materials, within the electric dipole approximation. Recently, it was found that the centrosymmetric magnetic semiconductors EuTe and EuSe can generate near-gap second harmonics, if the system is submitted to an external magnetic field. Here, a theoretical model is presented, which well describes the observed phenomena. The model shows that second harmonic generation becomes efficient when the magnetic dipole oscillations between the band-edge excited states of the system, induced by the excitation light, enter the in-phase regime, which can be achieved by applying a magnetic field to the material.