637 research outputs found

    Biochemical and haematological values in abattoir pigs with and without subclinical lesions

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    The biochemical and haematological profiles of 379 pigs with or without various gross pathological lesions in an abattoir in Zimbabwe were studied to see whether there were any differences between the levels of haematological and biochemical values, and health status (with and without pathological lesions). On the basis of observable gross pathology, 134 pigs were classified as having one or more subclinical lesions (liver milk spot, pneumonia, pleurisy, pericarditis, abscesses and arthritis). Seventy six of these were males and 58 females. There were observable sex differences in the mean haematological and biochemical values obtained. Erythrocyte counts showed significant differences in mean values (P < 0,05) among groups of pigs found with various pathological lesions. The biochemical values showed significant group differences for ALP, ALT. AST, and LDH.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat X Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.University of Zimbabwe Research Boardmn201

    Seashore disturbance and management of the clonal Arctophila fulva : Modelling patch dynamics

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    Question: What is the population viability of a critically endangered seashore grass, Arctophila fulva var. pendulina. Location: Liminka Bay, W Finland, 25°21'70 N, 64°51'90 E. Methods: We constructed a matrix population model based on colonization and disappearance events and patch size changes of A. fulva. Patches were divided into hydric and nonhydric zones according to proximity to the seashore and intensity of disturbance. Perturbation analyses were carried out in order to identify transitions critical for population growth. Seed bank and seed germination studies provided background information for the model design. Results: A. fulva patches observed in the more disturbed hydric zone (closest to the sea) increased in number, as did the total number of patches. However, the number of patches in the less disturbed non-hydric zone decreased. Conclusions: Short-term dynamics of the A. fulva population at Liminka Bay seem to be determined by environmental fluctuations, which cause annual variation in transition rates between patch size classes. The long-term dynamics are probably governed by initiation of primary succession by isostatic land uplift. Increased disturbance at the water’s edge may promote persistence of A. fulva through reduced interspecific competition. Our results suggest that shoreline disturbance of the hydric zone is sufficient for maintaining a viable population. Competitive exclusion of A. fulva in the non-hydric zone may be delayed by management practices, such as mowing

    Entanglement in bipartite generalized coherent states

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    Entanglement in a class of bipartite generalized coherent states is discussed. It is shown that a positive parameter can be associated with the bipartite generalized coherent states so that the states with equal value for the parameter are of equal entanglement. It is shown that the maximum possible entanglement of 1 bit is attained if the positive parameter equals 2\sqrt{2}. The result that the entanglement is one bit when the relative phase between the composing states is π\pi in bipartite coherent states is shown to be true for the class of bipartite generalized coherent states considered.Comment: 10 pages, 4 figures; typos corrected and figures redrawn for better clarit

    Bayesian classification of vegetation types with Gaussian mixture density fitting to indicator values.

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    Question: Is it possible to mathematically classify relevés into vegetation types on the basis of their average indicator values, including the uncertainty of the classification? Location: The Netherlands. Method: A large relevé database was used to develop a method for predicting vegetation types based on indicator values. First, each relevé was classified into a phytosociological association on the basis of its species composition. Additionally, mean indicator values for moisture, nutrients and acidity were computed for each relevé. Thus, the position of each classified relevé was obtained in a three-dimensional space of indicator values. Fitting the data to so called Gaussian Mixture Models yielded densities of associations as a function of indicator values. Finally, these density functions were used to predict the Bayesian occurrence probabilities of associations for known indicator values. Validation of predictions was performed by using a randomly chosen half of the database for the calibration of densities and the other half for the validation of predicted associations. Results and Conclusions: With indicator values, most relevés were classified correctly into vegetation types at the association level. This was shown using confusion matrices that relate (1) the number of relevés classified into associations based on species composition to (2) those based on indicator values. Misclassified relevés belonged to ecologically similar associations. The method seems very suitable for predictive vegetation models

    Force and Motion Generation of Molecular Motors: A Generic Description

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    We review the properties of biological motor proteins which move along linear filaments that are polar and periodic. The physics of the operation of such motors can be described by simple stochastic models which are coupled to a chemical reaction. We analyze the essential features of force and motion generation and discuss the general properties of single motors in the framework of two-state models. Systems which contain large numbers of motors such as muscles and flagella motivate the study of many interacting motors within the framework of simple models. In this case, collective effects can lead to new types of behaviors such as dynamic instabilities of the steady states and oscillatory motion.Comment: 29 pages, 9 figure

    Generation of atom-photon entangled states in atomic Bose-Einstein condensate via electromagnetically induced transparency

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    In this paper, we present a method to generate continuous-variable-type entangled states between photons and atoms in atomic Bose-Einstein condensate (BEC). The proposed method involves an atomic BEC with three internal states, a weak quantized probe laser and a strong classical coupling laser, which form a three-level Lambda-shaped BEC system. We consider a situation where the BEC is in electromagnetically induced transparency (EIT) with the coupling laser being much stronger than the probe laser. In this case, the upper and intermediate levels are unpopulated, so that their adiabatic elimination enables an effective two-mode model involving only the atomic field at the lowest internal level and the quantized probe laser field. Atom-photon quantum entanglement is created through laser-atom and inter-atomic interactions, and two-photon detuning. We show how to generate atom-photon entangled coherent states and entangled states between photon (atom) coherent states and atom-(photon-) macroscopic quantum superposition (MQS) states, and between photon-MQS and atom-MQS states.Comment: 9 pages, 1 figur

    Multiorder coherent Raman scattering of a quantum probe field

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    We study the multiorder coherent Raman scattering of a quantum probe field in a far-off-resonance medium with a prepared coherence. Under the conditions of negligible dispersion and limited bandwidth, we derive a Bessel-function solution for the sideband field operators. We analytically and numerically calculate various quantum statistical characteristics of the sideband fields. We show that the multiorder coherent Raman process can replicate the statistical properties of a single-mode quantum probe field into a broad comb of generated Raman sidebands. We also study the mixing and modulation of photon statistical properties in the case of two-mode input. We show that the prepared Raman coherence and the medium length can be used as control parameters to switch a sideband field from one type of photon statistics to another type, or from a non-squeezed state to a squeezed state and vice versa.Comment: 12 pages, 7 figures, to be published in Phys. Rev.
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