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2233. Apple aphid, Aphis spp. (Hemiptera: Aphididae), and predator populations in an apple orchard at the non-bearing stage: The impact of ground cover and cultivar

Creator:
Fréchette, Bruno, Cormier, Daniel, Chouinard, Gérald, Vanoosthuyse, Franz , and Éric , Lucas
Type:
article, model:article, and TEXT
Subject:
Predation, aphids, Aphis spp., aphidophagous predators, Harmonia axyridis, Aphidoletes aphidimyza, spiders, apple orchard, biological control, and conservation biological control
Language:
English
Description:
A two-year field experiment was conducted to determine whether a conservation biological control strategy could be applied to enhance the biological control of green apple aphids, Aphis spp., in a high-density and scab-resistant apple orchard at the non-bearing stage. The natural occurrence of aphid predators and their impact on aphid populations were evaluated in 2005. The impact of predation on aphid densities was evaluated by comparing a predator exclusion treatment with a control. In 2006, the possibility to enhance predator abundance/performance and aphid biological control with a flowering ground cover was tested: trees were grown either with a flowering ground cover of phacelia, Phacelia tanacetifolia Bentham, and buckwheat, Fagopyrum esculentum Moench, or with a conventional ground cover of mixed Poaceae species. In 2006, it was also determined whether aphid densities differ between Liberty and Topaz, 2 scab-resistant cultivars. Results indicate that the predatory arthropod community was dominated by Coccinellidae, Cecidomyiidae, and various spider species. The ladybird community was dominated by the exotic species Harmonia axyridis Pallas, and the abundance of this species was correlated with aphid density. Naturally occurring predators had little impact on aphid abundance, although the proportion of trees with aphid colonies was greater in the predator exclusion treatment on two consecutive dates in 2005. Ground cover types had no impact on aphid densities. The oviposition response of Cecidomyiidae to aphid density was greater in Liberty trees with flowering ground cover than with the conventional ground cover. Conversely, the response of ladybird adults to aphid density was more important in Topaz trees with the conventional ground cover than with the flowering ground cover. Finally, no difference occurred in aphid abundance between Liberty and Topaz trees. Those results are discussed from a biological control and ecological point of view.
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

2234. Application of (L) sets to some classes of operators

Creator:
El Fahri, Kamal, Machrafi, Nabil, H'michane, Jawad, and Elbour, Aziz
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
(L) set, order (L)-Dunford-Pettis operator, weakly sequentially continuous lattice operations, and Banach lattice
Language:
English
Description:
The paper contains some applications of the notion of (L) sets to several classes of operators on Banach lattices. In particular, we introduce and study the class of order (L)-Dunford-Pettis operators, that is, operators from a Banach space into a Banach lattice whose adjoint maps order bounded subsets to an (L) sets. As a sequence characterization of such operators, we see that an operator T : X → E from a Banach space into a Banach lattice is order (L)-Dunford-Pettis, if and only if |T (xn)| → 0 for σ(E, E′ ) for every weakly null sequence (xn) ⊂ X. We also investigate relationships between order (L)-DunfordPettis, AM-compact, weak* Dunford-Pettis, and Dunford-Pettis operators. In particular, it is established that each operator T : E → F between Banach lattices is Dunford-Pettis whenever it is both order (L)-Dunford-Pettis and weak* Dunford-Pettis, if and only if E has the Schur property or the norm of F is order continuous.
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

2235. Application of a center manifold theory to a reaction-diffusion system of collective motion of camphor disks and boats

Creator:
Ei, Shin-Ichiro, Ikeda, Kota, Nagayama, Masaharu, and Tomoeda, Akiyasu
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
center manifold theory, bifurcation, traveling wave solution, and collective motion
Language:
English
Description:
Unidirectional motion along an annular water channel can be observed in an experiment even with only one camphor disk or boat. Moreover, the collective motion of camphor disks or boats in the water channel exhibits a homogeneous and an inhomogeneous state, depending on the number of disks or boats, which looks like a kind of bifurcation phenomena. In a theoretical research, the unidirectional motion is represented by a traveling wave solution in a model. Hence it suffices to investigate a linearized eigenvalue problem in order to prove the destabilization of a traveling wave solution. However, the eigenvalue problem is too difficult to analyze even if the number of camphor disks or boats is 2. Hence we need to make a reduction on the model. In the present paper, we apply the center manifold theory and reduce the model to an ordinary differential system.
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

2236. Application of a multiphase flow code for investigation of influence of capillary pressure parameters on two-phase flow

Creator:
Mikyška, Jiří and Illangasekare, Tissa H.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
two-phase flow, non-aquous phase liquids (NAPL), control volume finite elements, capillary pressure parameters, Brooks-Corey model, and plume sensitivity
Language:
English
Description:
We have developed a multiphase flow code that has been applied to study the behavior of non-aqueous phase liquids (NAPL) in the subsurface. We describe model formulation, discretization, and use the model for numerical investigation of sensitivity of the NAPL plume with respect to capillary parameters of the soil. In this paper the soil is assumed to be spatially homogeneous. A 2-D reference problem has been chosen and has been recomputed repeatedly with modified parameters of the Brooks-Corey capillary pressure model. In this paper we present selected figures showing the resulting plumes as well as quantitative information regarding position of the center of mass of the plume and variances (spreads) of the plume in both axes. These data allow us to evaluate influence of the capillary pressure parameters on the plume morphology in a way that has already been used for characterization of the plume distribution in laboratory experiments. Results confirm the hypothesis that capillary pressure parameters are the key quantities that determine the fate of organic contaminants in the subsurface, and emphasize the significance of the residual NAPL saturation for correct modeling of the NAPL contamination.
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

2237. Application of a New Set of Pseudo-Distances in Documents Categorization

Creator:
Gadri, S. and Moussaoui, A.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
N -grams, language identification, text categorization, text mining, machine learning, Kullback-Leibler distance, X2 distance, and Cavnar-Trenkle distance
Language:
English
Description:
Automatic text classification is a very important task that consists in assigning labels (categories, groups, classes) to a given text based on a set of previously labeled texts called training set. The work presented in this paper treats the problem of automatic topical text categorization. It is a supervised classification because it works on a predefined set of classes and topical because it uses topics or subjects of texts as classes. In this context, we used a new approach based on $k$-NN algorithm, as well as a new set of pseudo-distances (distance metrics) known in the field of language identification. We also proposed a simple and effective method to improve the quality of performed categorization.
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

2238. Application of a new type of aerodynamic tilting pad journal bearing in power gyroscope

Creator:
Šimek, Jiří
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
aerodynamic journal bearing, tilting pad bearing, foil bearing, rotor stability, power gyroscope, bearing damping, and elastic elements
Language:
English
Description:
New type of aerodynamic tilting pad journal bearing was designed and successfully tested in several applications, one of which was power gyroscope support. Bearing design combines advantages of foil bearings, i.e. additional damping achieved by squeezing out gas film and friction of elastic elements on bearing casing surface, with qualities of classical tilting pad bearings, consisting in defined geometry of bearing gap and excellent stability. Theoretical solution of bearing characteristic calculation is shortly described, consisting in numerical solution of gas flow in narrow gap. Some computed data and results of experiments with rotors operated up to 180.000 rpm are presented too. and Obsahuje seznam literatury
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

2239. Application of a probabilistic neural network for liquefaction assessment

Creator:
Xue, X., Yang, X., and Li, P.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
earthquake, soil liquefaction, probabilistic neural network, and particle swarm optimization
Language:
English
Description:
This paper presents a hybrid probabilistic neural network (PNN) and particle swarm optimization (PSO) techniques to predict the soil liquefaction. The PSO algorithm is employed in selecting the optimal smoothing parameter of the PNN to improve the forecasting accuracy. Seven parameters such as earthquake magnitude, normalized peak horizontal acceleration at ground surface, standard penetration number, penetration resistance, relative compaction, mean grain diameter and groundwater table are selected as the evaluating indices. The predictions from the PSO-PNN model were compared with those from two models: backpropagation neural network (BPNN) model and support vector machine (SVM) model. The study concluded that the proposed PSO-PNN model can be used as a reliable approach for predicting soil liquefaction.
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

2240. Application of acoustic emission for measuring of contact fatigue of axial bearing

Creator:
Hort, Filip and Mazal, Pavel
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
acoustic emission, axial bearings, contact fatigue, time domain, and maximal amplitude
Language:
English
Description:
This paper describes some results of an experiment aimed at monitoring of contact fatigue during the axial bearings tests. The needful of AE set-up for measuring of signal and Axmat stand for testing is presented here. The measuring of some kind of bearings required the creation of new clamping elements (Segment and Bearing bush) to the existing key point of Axmat stand. The results in this paper show records in the time domain mainly for counts and events. These events are filtered by maximal amplitude for better response on signal changes during the lifetime record. For these evaluated records there are shown the final failures of tested bearings and possible causes of failures beginning. and Obsahuje seznam literatury
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

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