2,210 research outputs found

    Comparison among Various Expressions of Complex Admittance for Quantum System in Contact with Heat Reservoir

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    Relation among various expressions of the complex admittance for quantum systems in contact with heat reservoir is studied. Exact expressions of the complex admittance are derived in various types of formulations of equations of motion under contact with heat reservoir. Namely, the complex admittance is studied in the relaxation method and the external-field method. In the former method, the admittance is calculated using the Kubo formula for quantum systems in contact with heat reservoir in no external driving fields, while in the latter method the admittance is directly calculated from equations of motion with external driving terms. In each method, two types of equation of motions are considered, i.e., the time-convolution (TC) equation and time-convolutionless (TCL) equation. That is, the full of the four cases are studied. It is turned out that the expression of the complex admittance obtained by using the relaxation method with the TC equation exactly coincides with that obtained by using the external-field method with the TC equation, while other two methods give different forms. It is also explicitly demonstrated that all the expressions of the complex admittance coincide with each other in the lowest Born approximation for the systemreservoir interaction. The formulae necessary for the higher order expansions in powers of the system-reservoir interaction are derived, and also the expressions of the admittance in the n-th order approximation are given. To characterize the TC and TCL methods, we study the expressions of the admittances of two exactly solvable models. Each exact form of admittance is compared with the results of the two methods in the lowest Born approximation. It is found that depending on the model, either of TC and TCL would be the better method.Comment: 34pages, no figur

    The social environment affects mate guarding behavior in Japanese beetles, Popillia japonica

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    The effect of the social environment on post-copulatory mate guarding duration in Japanese beetles, (Popillia japonica Newman), was examined in a laboratory experiment. The mate guarding durations of beetles in different sex ratios and densities were observed for 10 hours. Guarding duration was longer when females were larger, suggesting the presence of ‘cryptic’ male mate choice. Densities, but not sex ratio, affected the duration of guarding bouts, with males guarding for longer at higher densities. This result implies that males increase their guarding duration under conditions in which their female may be likely to be encountered by other males. The lack of a sex ratio effect on the duration of guarding bouts is consistent with other studies on this species that indicate males have difficulty distinguishing females from males. Consequently, because the sex ratio on food plants is typically male-biased, a paired male may react just to density, treating surrounding individuals as if they were mostly males. The total amount of time males spent guarding was lower at lower densities and at male-biased sex ratios; this suggests that after ceasing to guard one female, males were less able to find a subsequent mate under these conditions

    Enabling Personalized Composition and Adaptive Provisioning of Web Services

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    The proliferation of interconnected computing devices is fostering the emergence of environments where Web services made available to mobile users are a commodity. Unfortunately, inherent limitations of mobile devices still hinder the seamless access to Web services, and their use in supporting complex user activities. In this paper, we describe the design and implementation of a distributed, adaptive, and context-aware framework for personalized service composition and provisioning adapted to mobile users. Users specify their preferences by annotating existing process templates, leading to personalized service-based processes. To cater for the possibility of low bandwidth communication channels and frequent disconnections, an execution model is proposed whereby the responsibility of orchestrating personalized processes is spread across the participating services and user agents. In addition, the execution model is adaptive in the sense that the runtime environment is able to detect exceptions and react to them according to a set of rules

    A quasi-experimental approach to analyzing sexual appeal and gender in advertising – evidences from Brazil

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    Purpose – The use of sexual appeal in advertisements is a common practice in promotion, and its acceptance can vary throughout cultures. In the last twenty years, its use has been evaluated in several markets, including Brazil, where this research study was undertaken. The purpose of the study is to measure the effects of sexual appeal in advertisements on consumers, comparing the role of gender and perceptions about models’ idealized bodies.Design/Methodology/Approach – Two quasi-experiments were conducted on a dataset obtained from a non-probabilistic sample using online questionnaires. Both studies consider the effect of using sexual appeal in advertisements. The first used gym advertisements to compare the attitudes and purchase intention between men and women. The second assessed the use of female models with and without idealized appearance in beer advertisements.Findings and implications – It was observed that advertisements with low sexual appeal resulted in better evaluations; however, those with a higher level of sexual appeal were better evaluated by men if containing female models with characteristics typically considered to be attractive. On the other hand, women rated more highly the ads using female models with no features commonly regarded as attractive. Thus, it was concluded that gender can influence the advertising format to be adopted by companies: in the case of a female target audience, it is probably better to use models without “ideal” characteristics, but the opposite may have a more significant effect when it comes to a male target audience. This clearly incongruent perspective – gender-based bias – is a critical issue for managers and researchers.Limitations – This study only focused on a narrow dataset made up of Brazilian respondents, which was used as a non-probabilistic, convenience sample. Originality – This study is the first to use a quasi-experimental approach, connecting gender attitudes to brands and ads to bodies of idealized models and sexual appeal effects in ads.info:eu-repo/semantics/publishedVersio

    The {\L}ojasiewicz exponent of a set of weighted homogeneous ideals

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    We give an expression for the {\L}ojasiewicz exponent of a set of ideals which are pieces of a weighted homogeneous filtration. We also study the application of this formula to the computation of the {\L}ojasiewicz exponent of the gradient of a semi-weighted homogeneous function (\C^n,0)\to (\C,0) with an isolated singularity at the origin.Comment: 15 page

    Time-convolutionless reduced-density-operator theory of a noisy quantum channel: a two-bit quantum gate for quantum information processing

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    An exact reduced-density-operator for the output quantum states in time-convolutionless form was derived by solving the quantum Liouville equation which governs the dynamics of a noisy quantum channel by using a projection operator method and both advanced and retarded propagators in time. The formalism developed in this work is general enough to model a noisy quantum channel provided specific forms of the Hamiltonians for the system, reservoir, and the mutual interaction between the system and the reservoir are given. Then, we apply the formulation to model a two-bit quantum gate composed of coupled spin systems in which the Heisenberg coupling is controlled by the tunneling barrier between neighboring quantum dots. Gate Characteristics including the entropy, fidelity, and purity are calculated numerically for both mixed and entangled initial states

    Soft x-ray magnetic circular dichroism study of weakly ferromagnetic Zn1x_{1-x}Vx_xO thin film

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    We performed a soft x-ray magnetic circular dichroism (XMCD) study of a Zn1x_{1-x}Vx_xO thin film which showed small ferromagnetic moment. Field and temperature dependences of V 2pp XMCD signals indicated the coexistence of Curie-Weiss paramagnetic, antiferromagnetic, and possibly ferromagnetic V ions, quantitatively consistent with the magnetization measurements. We attribute the paramagnetic signal to V ions substituting Zn sites which are somewhat elongated along the c-axis

    Lojasiewicz exponent of families of ideals, Rees mixed multiplicities and Newton filtrations

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    We give an expression for the {\L}ojasiewicz exponent of a wide class of n-tuples of ideals (I1,...,In)(I_1,..., I_n) in \O_n using the information given by a fixed Newton filtration. In order to obtain this expression we consider a reformulation of {\L}ojasiewicz exponents in terms of Rees mixed multiplicities. As a consequence, we obtain a wide class of semi-weighted homogeneous functions (Cn,0)(C,0)(\mathbb{C}^n,0)\to (\mathbb{C},0) for which the {\L}ojasiewicz of its gradient map f\nabla f attains the maximum possible value.Comment: 25 pages. Updated with minor change

    A Conditional Yeast E1 Mutant Blocks the Ubiquitin–Proteasome Pathway and Reveals a Role for Ubiquitin Conjugates in Targeting Rad23 to the Proteasome

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    E1 ubiquitin activating enzyme catalyzes the initial step in all ubiquitin-dependent processes. We report the isolation of uba1-204, a temperature-sensitive allele of the essential Saccharomyces cerevisiae E1 gene, UBA1. Uba1-204 cells exhibit dramatic inhibition of the ubiquitin–proteasome system, resulting in rapid depletion of cellular ubiquitin conjugates and stabilization of multiple substrates. We have employed the tight phenotype of this mutant to investigate the role ubiquitin conjugates play in the dynamic interaction of the UbL/UBA adaptor proteins Rad23 and Dsk2 with the proteasome. Although proteasomes purified from mutant cells are intact and proteolytically active, they are depleted of ubiquitin conjugates, Rad23, and Dsk2. Binding of Rad23 to these proteasomes in vitro is enhanced by addition of either free or substrate-linked ubiquitin chains. Moreover, association of Rad23 with proteasomes in mutant and wild-type cells is improved upon stabilizing ubiquitin conjugates with proteasome inhibitor. We propose that recognition of polyubiquitin chains by Rad23 promotes its shuttling to the proteasome in vivo

    Nonlinear dynamic analysis of an optimal particle damper

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    We study the dynamical behavior of a single degree of freedom mechanical system with a particle damper. The particle (granular) damping was optimized for the primary system operating condition by using an appropriate gap size for a prismatic enclosure. The particles absorb the kinetic energy of the vibrating structure and convert it into heat through the inelastic collisions and friction. This results in a highly nonlinear mechanical system. Considering linear signal analysis, state space reconstruction, Poincar\'e sections and the determination of maximal Lyapunov exponents, the motion of the granular system inside the enclosure is characterized for a wide frequency range. With the excitation frequency as control parameter, either regular and chaotic motion of the granular bed are found and their influence on the damping is analyzed.Comment: 18 pages, 8 figures. arXiv admin note: text overlap with arXiv:1105.030
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