2,285 research outputs found

    Forage herbs improve mineral composition of grassland herbage

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    Provision of an adequate mineral supply in the diets of ruminants fed mainly on grassland herbage can present a challenge if mineral concentrations are suboptimal for animal nutrition. Forage herbs may be included in grassland seed mixtures to improve herbage mineral content, although there is limited information about mineral concentrations in forage herbs. To determine whether herbs have greater macro- and micromineral concentrations than forage legumes and grasses, we conducted a 2-year experiment on a loamy-sand site in Denmark sown with a multi-species mixture comprised of three functional groups (grasses, legumes and herbs). Herb species included chicory (Cichorium intybus L.), plantain (Plantago lanceolata L.), caraway (Carum carvi L.) and salad burnet (Sanguisorba minor L.). We also investigated the effect of slurry application on the macro- and micromineral concentration of grasses, legumes and herbs. In general, herbs had greater concentrations of the macrominerals P, Mg, K and S and the microminerals Zn and B than grasses and legumes. Slurry application indirectly decreased Ca, S, Cu and B concentrations of total herbage because of an increase in the proportion of mineral-poor grasses. Our study indicates that including herbs in forage mixtures is an effective way of increasing mineral concentrations in herbage

    Nonuniversality in the pair contact process with diffusion

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    We study the static and dynamic behavior of the one dimensional pair contact process with diffusion. Several critical exponents are found to vary with the diffusion rate, while the order-parameter moment ratio m=\bar{rho^2} /\bar{rho}^2 grows logarithmically with the system size. The anomalous behavior of m is traced to a violation of scaling in the order parameter probability density, which in turn reflects the presence of two distinct sectors, one purely diffusive, the other reactive, within the active phase. Studies restricted to the reactive sector yield precise estimates for exponents beta and nu_perp, and confirm finite size scaling of the order parameter. In the course of our study we determine, for the first time, the universal value m_c = 1.334 associated with the parity-conserving universality class in one dimension.Comment: 9 pages, 5 figure

    Coherent radiation of atoms and a channeling particle

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    New mechanism of radiation emitted at channeling of a relativistic particle in a crystal is studied. Superposition of coherent radiation of the atoms in a crystal lattice which are excited by a channeling particle and radiation of the channeling particle itself is considered. It is shown that coherent radiation of the chain of oscillating atoms forms a resonance peak on the background of radiation of the channeling particle.Comment: 7 pages, 4 figure

    Protocols for entanglement transformations of bipartite pure states

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    We present a general theoretical framework for both deterministic and probabilistic entanglement transformations of bipartite pure states achieved via local operations and classical communication. This framework unifies and greatly simplifies previous works. A necessary condition for ``pure contraction'' transformations is given. Finally, constructive protocols to achieve both probabilistic and deterministic entanglement transformations are presented.Comment: 7 pages, no figures. Version slightly modified on Physical Review A reques

    Oral salmon calcitonin reduces cartilage and bone pathology in an osteoarthritis rat model with increased subchondral bone turnover

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    SummaryObjectivesTraumatic osteoarthritis (OA) is possibly augmented by effects from loss of sex hormones. Salmon calcitonin is shown to reduce OA pathogenesis and bone resorption. We investigated the effects of oral salmon calcitonin treatment and ovariectomy on cartilage and bone pathology in a traumatic OA model.MethodsSix groups with 10 7-month-old female Sprague Dawley rats each were subjected to bilateral meniscectomy (MNX), ovariectomy (OVX) or Sham surgery and treated for 8 weeks with oral salmon calcitonin (CT) or vehicle (V) in the following way: (1) Sham+V; (2) MNX+V; (3) MNX+CT; (4) OVX+V; (5) MNX/OVX+V; (6) MNX/OVX+CT. Weights were recorded weekly and CTX-II was measured in serum. At termination 56 days post-surgery, the right tibia was analyzed for changes in articular cartilage thickness, extent of cartilage damage and subchondral bone changes in predefined zones, as recommended in the novel OARSI histopathology score.ResultsThe combined MNX/OVX model produced a significantly reduced cartilage thickness (P=0.033) in the outer zone (Z1) of the tibial plateau and increased calcified cartilage damage (P=0.0004) and serum CTX-II (P=0.003). Addition of OVX to MNX significantly increased the width of matrix damage at the surface (P=0.025) and 50% cartilage depth (P=0.004). Treatment with oral salmon calcitonin counteracted the loss of cartilage thickness (P=0.055), significantly reduced subchondral bone damage score (P=0.019) and reduced the type II collagen degradation (P=0.009).ConclusionsAddition of ovariectomy augmented site-specific traumatic OA pathology, which was reduced by oral salmon calcitonin treatment. Treatments for OA might ideally affect both bone and cartilage

    Epidemic processes with immunization

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    We study a model of directed percolation (DP) with immunization, i.e. with different probabilities for the first infection and subsequent infections. The immunization effect leads to an additional non-Markovian term in the corresponding field theoretical action. We consider immunization as a small perturbation around the DP fixed point in d<6, where the non-Markovian term is relevant. The immunization causes the system to be driven away from the neighbourhood of the DP critical point. In order to investigate the dynamical critical behaviour of the model, we consider the limits of low and high first infection rate, while the second infection rate remains constant at the DP critical value. Scaling arguments are applied to obtain an expression for the survival probability in both limits. The corresponding exponents are written in terms of the critical exponents for ordinary DP and DP with a wall. We find that the survival probability does not obey a power law behaviour, decaying instead as a stretched exponential in the low first infection probability limit and to a constant in the high first infection probability limit. The theoretical predictions are confirmed by optimized numerical simulations in 1+1 dimensions.Comment: 12 pages, 11 figures. v.2: minor correction

    Mindful Parenting, Parenting Cognitions, and Parent-Youth Communication: Bidirectional Linkages and Mediational Processes

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    Objectives: Mindful parenting and parenting cognitions likely have important linkages to each other and to parent-child communication, but these linkages have not been tested. In this article, we test the bidirectional linkages between mindful parenting and parenting cognitions (sense of competence, parent-centered attributions) and the underlying mediational processes that link them to parent-child communication (parental solicitation and youth disclosure). Methods: Longitudinal, autoregressive cross-lagged models were run within a longitudinal sample of rural and suburban early adolescents and their mothers (n = 421; mean adolescent age = 12.14, 46% male, 73% white). Results: Significant bidirectional linkages were found between mindful parenting and parenting cognitions across Time 1 and Time 2. Greater mindful parenting at Time 1 was associated with more positive parenting cognitions (e.g., greater perceptions of parental competence and fewer negative parent-centered attributions or self-blame) at Time 2. More positive parenting cognitions at Time 1 were also associated with greater levels of mindful parenting at Time 2. Mindful parenting at Time 2 mediated the association between parenting cognitions (both parent-centered attributions and sense of competence) at Time 1 and parental solicitation at Time 3. Conclusions: Mindful parenting and parenting cognitions influence each other over time. Parenting cognitions can affect parental solicitation via increases in mindful parenting. The discussion focuses on potential underlying processes

    Percolation and epidemics in a two-dimensional small world

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    Percolation on two-dimensional small-world networks has been proposed as a model for the spread of plant diseases. In this paper we give an analytic solution of this model using a combination of generating function methods and high-order series expansion. Our solution gives accurate predictions for quantities such as the position of the percolation threshold and the typical size of disease outbreaks as a function of the density of "shortcuts" in the small-world network. Our results agree with scaling hypotheses and numerical simulations for the same model.Comment: 7 pages, 3 figures, 2 table

    From multiplicative noise to directed percolation in wetting transitions

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    A simple one-dimensional microscopic model of the depinning transition of an interface from an attractive hard wall is introduced and investigated. Upon varying a control parameter, the critical behaviour observed along the transition line changes from a directed-percolation to a multiplicative-noise type. Numerical simulations allow for a quantitative study of the multicritical point separating the two regions, Mean-field arguments and the mapping on a yet simpler model provide some further insight on the overall scenario.Comment: 4 pages, 3 figure
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