3,630 research outputs found
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
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
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
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
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 and an
interlattice quantum Ising interaction in the presence of a transverse field
. The interlattice coupling is a random Gaussian distributed variable
(with average and variance ) while the 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 and to allow, as previously,
a better comparison with the experimental findings.
The results indicate the presence of a SG solution at low and for
temperature ( is the freezing temperature). When is
increased, a mixed phase AF+SG appears, then an AF solution and finally a Kondo
state is obtained for high values of . Moreover, the behaviors of the
freezing and Neel temperatures are also affected by the relationship between
and the transverse field . 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
, if is assumed to increase with , 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
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 . The problem is formulated in a Grassmann path
integral formalism within the static approximation. In this model, a parallel
magnetic field 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 increase the difference between
the RSB solutions of each sublattice. The freezing temperature shows a higher
increase with when 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 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, 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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