3,077 research outputs found

    Multidimensional perfectionism and assortative mating: A perfect date?

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    Assortative mating has been found regarding personality traits, personal attitudes and values, and cognitive abilities, but so far no study has investigated assortative mating regarding multidimensional perfectionism. A total of 422 participants from a non-commercial panel (mean age = 36.0 years) completed measures of self-oriented, other-oriented, and socially prescribed perfectionism and rated the attractiveness of four potential dating partners (“dates”): a self-oriented, an other-oriented, a socially prescribed, and a non-perfectionist date. Results showed that all perfectionist dates were seen as less attractive than the non-perfectionist date. This effect, however, was moderated by self-oriented and other-oriented perfectionism. Participants high in self-oriented perfectionism found all three perfectionist dates more attractive than participants low in self-oriented perfections. Participants high in other-oriented perfectionism found the self-oriented perfectionist date more attractive, and the non-perfectionist date less attractive than participants low in other-oriented perfectionism. The findings are discussed with respect to assortative mating, the social disconnection model of perfectionism, and the heritability of perfectionism

    Intrinsic quark transverse momentum in the nucleon from lattice QCD

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    A better understanding of transverse momentum (k_T-) dependent quark distributions in a hadron is needed to interpret several experimentally observed large angular asymmetries and to clarify the fundamental role of gauge links in non-abelian gauge theories. Based on manifestly non-local gauge invariant quark operators we introduce process-independent k_T-distributions and study their properties in lattice QCD. We find that the longitudinal and transverse momentum dependence approximately factorizes, in contrast to the behavior of generalized parton distributions. The resulting quark k_T-probability densities for the nucleon show characteristic dipole deformations due to correlations between intrinsic k_T and the quark or nucleon spin. Our lattice calculations are based on N_f=2+1 mixed action propagators of the LHP collaboration.Comment: 4 pages, 3 figure

    Broadband suppression of phase-noise with cascaded phase-locked-loops for the generation of frequency ramps

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    The generation of analogue frequency ramps with non-fractional phase-locked-loops (PLL) is a cost effective way of linearising varactor controlled oscillators (VCO). In case that the VCO shows a high phase-noise level, a single non-fractional PLL is not able to suppress the phase-noise of the VCO sufficiently. The reason for this is the limited loopbandwidth of the PLL. In the field of precise measurements a high phase-noise level is mostly not tolerable. Examples of VCO-types with an extremely high phase noise level are integrated millimetre wave oscillators based on GaAs-HEMT technology. Both, a low quality factor of the resonator and a high flicker-noise corner frequency of the transistors are the main reason for the poor phase-noise behaviour. On the other hand this oscillator type allows a cost effective implementation of a millimetre-wave VCO. Therefore, a cascaded two-loop structure is presented that is able to linearise a VCO and additionally to reduce its phase-noise significantly

    Outline of an Anthropological Contribution to the Study of Snake Venom Variability: The Case of Echis sp. Envenomation

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    An understanding of the variability of snake venom composition is of high relevance for adequate treatment of snakebites. Clinical observations of bite victims are considered as a first step in the study of venom variability. The present paper suggests the study of local clinical observations made by healers as an anthropological contribution to the interdisci-plinary research of venom variability on a species and subspecies level. Such an anthropological contribution will take into account cultural particularities of a region. In order to illustrate his approach, the author describes his ethnozoological and ethnomedical fieldwork among Zarma and Tuareg in western Niger where he studied envenomation by Echis leucogaster. This species is of particular interest, as no medical descriptions of envenomation resulting from its bites seem to exist.</p

    Exploring quark transverse momentum distributions with lattice QCD

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    We discuss in detail a method to study transverse momentum dependent parton distribution functions (TMDs) using lattice QCD. To develop the formalism and to obtain first numerical results, we directly implement a bi-local quark-quark operator connected by a straight Wilson line, allowing us to study T-even, "process-independent" TMDs. Beyond results for x-integrated TMDs and quark densities, we present a study of correlations in x and transverse momentum. Our calculations are based on domain wall valence quark propagators by the LHP collaboration calculated on top of gauge configurations provided by MILC with 2+1 flavors of asqtad-improved staggered sea quarks.Comment: 36 pages, 24 figures; revised version of May 2011, one appendix adde

    Lattice QCD study of the Boer-Mulders effect in a pion

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    The three-dimensional momenta of quarks inside a hadron are encoded in transverse momentum-dependent parton distribution functions (TMDs). This work presents an exploratory lattice QCD study of a TMD observable in the pion describing the Boer-Mulders effect, which is related to polarized quark transverse momentum in an unpolarized hadron. Particular emphasis is placed on the behavior as a function of a Collins-Soper evolution parameter quantifying the relative rapidity of the struck quark and the initial hadron, e.g., in a semi-inclusive deep inelastic scattering (SIDIS) process. The lattice calculation, performed at the pion mass m_pi = 518 MeV, utilizes a definition of TMDs via hadronic matrix elements of a quark bilocal operator with a staple-shaped gauge connection; in this context, the evolution parameter is related to the staple direction. By parametrizing the aforementioned matrix elements in terms of invariant amplitudes, the problem can be cast in a Lorentz frame suited for the lattice calculation. In contrast to an earlier nucleon study, due to the lower mass of the pion, the calculated data enable quantitative statements about the physically interesting limit of large relative rapidity. In passing, the similarity between the Boer-Mulders effects extracted in the pion and the nucleon is noted.Comment: 16 pages, 9 figures, 3 table

    A neighbor of Gonoa: : "The Man of Bunige" and his game

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    This article presents the rock art site of Bunige in northern Tibesti (Republic of Chad). Bunige is located barely ten kilometers from the rock art site of Gonoa and, except for a short mention in a French article from 1966, does not seem to have been explored in any detail. In addition to engravings of cattle, wild animals, and round devices, there is an almost man-sized depiction of an archer. Such large depictions of humans are very rare in the Tibesti, which makes this ‘Man of Bunige’ in close proximity to the famous ‘Man of Gonoa’ all the more significant. For this reason, the present article describes the rock art site of Bunige in detail. Assuming that the ‘Man of Bunige’ represents a hunter, particular attention will be payed to representations of game and traps at this site. In fact, Bunige, due to its abundance of water, may have attracted wild animals and therefore may have been of particular interest to hunters
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