3,630 research outputs found

    Biography of John F. Enders and His Contributions to Microbiology

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    Control of the woolly apple aphid (Erisoma lanigerum Hausm.) by releasing earwigs (Forficula auricularia L.) and support oil applications - an interim report of first year results

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    The woolly apple aphid (Erisoma lanigerum Hausm.) has been recognised for some years as a serious pest in organic fruit growing where they may cause severe economic damage due to a lack of control strategies. Based on preliminary results a new project has been started in 2007 testing combinations of releasing earwigs and oil applications in order to develop an onfarm control strategy. In this paper we present preliminary results of the first year of the project´s field trials. They showed good efficacies for applying oil preparations by brush. The efficacy of releasing earwigs depended on the infestation intensity

    Sagnac interferometry based on ultra-slow polaritons in cold atomic vapors

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    The advantages of light and matter-wave Sagnac interferometers -- large area on one hand and high rotational sensitivity per unit area on the other -- can be combined utilizing ultra-slow light in cold atomic gases. While a group-velocity reduction alone does not affect the Sagnac phase shift, the associated momentum transfer from light to atoms generates a coherent matter-wave component which gives rise to a substantially enhanced rotational signal. It is shown that matter-wave sensitivity in a large-area interferometer can be achieved if an optically dense vapor at sub-recoil temperatures is used. Already a noticeable enhancement of the Sagnac phase shift is possible however with much less cooling requirements.Comment: 4 pages, 3 figure

    Whose education counts? The impact of grown children's education on the physical functioning of their parents in Tawian

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    Journal ArticleResearch has identified education as an important predictor of physical functioning in old age. Older adults in Taiwan tend to experience close ties to family members and high rates of adult child coresidence, much more so than is typical in Western cultures. These circumstances might imply additional health-related benefits stemming from the education of grown children. This association could arise in a number of ways, for instance through the sharing of health-related information between child and parent, the quality of caregiving efforts, monetary assistance for medical and other services, or through other psychosocial avenues. In this study, a nationally representative survey of older Taiwanese is employed to examine these concurrent effects. Outcome variables include the existence of any functional limitations (dichotomously measured) and the severity of functional disorders (ordinally measured). Dichotomous and ordinal logistic models are employed. Results suggest that, after adjusting for age, sex, and other factors, both child's and parent's education have an impact on the existence of physical limitations; however, the child's education is more important than the parent's in predicting severity of limitations. This finding implies that models ignoring social network characteristics in the effort to determine health outcomes of older adults may be misspecified, at least in some non-Western societies

    Quantum critical point in the spin glass-antiferromagnetism competition in Kondo-lattice systems

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    A theory is proposed to describe the competition among antiferromagnetism (AF), spin glass (SG) and Kondo effect. The model describes two Kondo sublattices with an intrasite Kondo interaction strength JKJ_{K} and an interlattice quantum Ising interaction in the presence of a transverse field Γ\Gamma. The interlattice coupling is a random Gaussian distributed variable (with average −2J0/N-2J_0/N and variance 32J2/N32 J^{2}/N) while the Γ\Gamma field is introduced as a quantum mechanism to produce spin flipping. The path integral formalism is used to study this fermionic problem where the spin operators are represented by bilinear combinations of Grassmann fields. The disorder is treated within the framework of the replica trick. The free energy and the order parameters of the problem are obtained by using the static ansatz and by choosing both J0/JJ_0/J and Γ/J≈(Jk/J)2\Gamma/J \approx (J_k/J)^2 to allow, as previously, a better comparison with the experimental findings. The results indicate the presence of a SG solution at low JK/JJ_K/J and for temperature T<TfT<T_{f} (TfT_{f} is the freezing temperature). When JK/JJ_K/J is increased, a mixed phase AF+SG appears, then an AF solution and finally a Kondo state is obtained for high values of JK/JJ_{K}/J. Moreover, the behaviors of the freezing and Neel temperatures are also affected by the relationship between JKJ_{K} and the transverse field Γ\Gamma. The first one presents a slight decrease while the second one decreases towards a Quantum Critical Point (QCP). The obtained phase diagram has the same sequence as the experimental one for Ce2Au1−xCoxSi3Ce_{2}Au_{1-x}Co_{x}Si_{3}, if JKJ_{K} is assumed to increase with xx, and in addition, it also shows a qualitative agreement concerning the behavior of the freezing and the Neel temperatures.Comment: 11 pages, 3 figures, accepted for publication in J. Phys.

    One-step replica symmetry breaking solution for a highly asymmetric two-sublattice fermionic Ising spin glass model in a transverse field

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    The one-step replica symmetry breaking (RSB) is used to study a two-sublattice fermionic infinite-range Ising spin glass (SG) model in a transverse field Γ\Gamma. The problem is formulated in a Grassmann path integral formalism within the static approximation. In this model, a parallel magnetic field HH breaks the symmetry of the sublattices. It destroys the antiferromagnetic (AF) order, but it can favor the nonergodic mixed phase (SG+AF) characterizing an asymmetric RSB region. In this region, intra-sublattice disordered interactions VV increase the difference between the RSB solutions of each sublattice. The freezing temperature shows a higher increase with HH when VV enhances. A discontinue phase transition from the replica symmetry (RS) solution to the RSB solution can appear with the presence of an intra-sublattice ferromagnetic average coupling. The Γ\Gamma field introduces a quantum spin flip mechanism that suppresses the magnetic orders leading them to quantum critical points. Results suggest that the quantum effects are not able to restore the RS solution. However, in the asymmetric RSB region, Γ\Gamma can produce a stable RS solution at any finite temperature for a particular sublattice while the other sublattice still presents RSB solution for the special case in which only the intra-sublattice spins couple with disordered interactions.Comment: 11 pages, 8 figures, accepted for publication in Phys. Rev.
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