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26042. Weighted sub-Bergman Hilbert spaces in the unit disk.
- Creator:
- Abkar, Ali and Jafarzadeh, B.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- weighted Bergman space, sub-Bergman Hilbert space, weighted Toeplitz operator, and reproducing kernel
- Language:
- English
- Description:
- We study sub-Bergman Hilbert spaces in the weighted Bergman space $A^2_\alpha $. We generalize the results already obtained by Kehe Zhu for the standard Bergman space $A^2$.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
26043. Weighty matters: Body size, diet and specialization in aphidophagous ladybird beetles (Coleoptera: Coccinellidae)
- Creator:
- Sloggett, John J.
- Type:
- article, model:article, and TEXT
- Subject:
- Body size, prey size, prey density, capture efficiency, dietary breadth, specialization, Coccinellidae, and aphids
- Language:
- English
- Description:
- Aphidophagous ladybirds exhibit a broad range of body sizes. Until now this has been thought to be a function of the different prey densities that they feed at, with smaller ladybirds feeding at lower prey densities. The size of the prey species they feed on has been considered to have no relationship with ladybird body size. However, these arguments possess a limited capacity to explain observed data from the field. I here demonstrate a more realistic, complex approach incorporating both prey density and the size of prey species. Small ladybirds can feed on small aphids at both low and high densities. However when the aphid species is large they cannot catch the older, bigger, more energy-rich aphid instars due to their small size. They are thus unable to feed on large aphid prey at low densities, although at higher densities numbers of the smaller instars may be sufficient to sustain them. By contrast large ladybirds can feed on large aphids at both low and high densities due to their superior ability to catch the bigger, more energy-rich older aphids; however they cannot be sustained by low densities of small aphids due to food limitation consequent on their large size. This more complex association between ladybird size, prey size and prey density possesses a better explanatory power for earlier field data. Because of this relationship, ladybird body size also provides an important trade-off determining dietary breadth and specialization in the aphidophagous Coccinellidae. Dietary specialists more closely match the size of their limited prey species, have higher overall capture efficiencies and can thus continue to reproduce at lower aphid densities for longer. By contrast dietary generalists adopt a one-size-fits-all strategy, are medium-sized and have lower capture efficiencies of individual prey species, thus requiring higher aphid densities. The role of body-size in dietary specialization is supported by data from the British fauna. Rather than trade-offs related to prey chemistry, which have hitherto been the centre of attention, body size trade-offs are the likely most important universal factor underlying dietary specialization in aphidophagous coccinellids.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
26044. Weil bundles and jet spaces
- Creator:
- Muñoz, J., Rodríguez, Josemar, and Muriel, F. J.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- jet near point contact element Weil bundle fundamental identification, near point, contact element, Weil bundle, and fundamental identification
- Language:
- English
- Description:
- In this paper we give a new definition of the classical contact elements of a smooth manifold M as ideals of its ring of smooth functions: they are the kernels of Weil’s near points. Ehresmann’s jets of cross-sections of a fibre bundle are obtained as a particular case. The tangent space at a point of a manifold of contact elements of M is shown to be a quotient of a space of derivations from the same ringC∞(M) into certain finite-dimensional local algebras. The prolongation of an ideal of functions from a Weil bundle to another one is the same ideal, when its functions take values into certain Weil algebras; following the same idea vector fields are prolonged, without any considerations about local one-parameter groups. As a consequence, we give an algebraic definition of Kuranishi’s fundamental identification on Weil bundles, and study their affine structures, as a generalization of the classical results on spaces of jets of cross-sections.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
26045. Weketrema gen. n., a new genus for Weketrema hawaiiense (Yamaguti, 1970) comb. n. (Digenea: Lecithasteridae) recently found in Australian marine fishes
- Creator:
- Bray, Rodney A. and Cribb, Thomas H.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- Digenea, Lecithasteridae, Weketrema, Scolopsis, Plectorhinchus, Cheilodactylus, Latridopsis, Great Barrier Reef, and Tasmania
- Language:
- English
- Description:
- A new genus, Weketrema, is erected in the family Lecithasteridae for the species hitherto known as Lecithophyllum hawaiiense. Weketrema hawaiiense (Yamaguti, 1970) comb. n. is redescribed from Scolopsis bilineatus (Bloch) (Perciformes: Nemipteridae) from Lizard Island and Heron Island, Queensland, Plectorhinchus gibbosus (Lacepède) (Perciformes: Haemulidae) from Heron Island and Cheilodactylus nigripes Richardson (Perciformes: Cheilodactylidae) and Latridopsis forsteri (Castelnau) (Perciformes: Latridae) from Stanley, northern Tasmania. The new genus is distinguished from related members of the family Lecithasteridae by its complete lack of a sinus-sac. Although placed in the subfamily Lecithasterinae pro tem, its true subfamily position is not entirely clear. Comment is made on its unusual distribution, both in terms of zoogeography and hosts.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
26046. Welcome address
- Creator:
- Tachezy, Ruth.
- Type:
- model:article and TEXT
- Language:
- English
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
26047. Welcome address
- Creator:
- Šteflová, Alena.
- Type:
- model:article and TEXT
- Language:
- English
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
26048. Welding process optimization with artificial neural network applications
- Creator:
- Aktepe, Adnan, Ersöz , Süleyman, and Lüy, Murat
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- Artificial neural networks, welding process control, and weld operation
- Language:
- English
- Description:
- Correct detection of input and output parameters of a welding process is significant for successful development of an automated welding operation. In welding process literature, we observe that output parameters are predicted according to given input parameters. As a new approach to previous efforts, this paper presents a new modeling approach on prediction and classification of welding parameters. 3 different models are developed on a critical welding process based on Artificial Neural Networks (ANNs) which are (i) Output parameter prediction, (ii) Input parameter prediction (reverse application of output prediction model) and (iii) Classification of products. In this study, firstly we use Pareto Analysis for determining uncontrollable input parameters of the welding process based on expert views. With the help of these analysis, 9 uncontrollable parameters are determined among 22 potential parameters. Then, the welding process of ammunition is modeled as a multi-input multi-output process with 9 input and 3 output parameters. 1st model predicts the values of output parameters according to given input values. 2nd model predicts the values of correct input parameter combination for a defect-free weld operation and 3rd model is used to classify the products whether defected or defect-free. 3rd model is also used for validation of results obtained by 1st and 2nd models. A high level of performance is attained by all the methods tested in this study. In addition, the product is a strategic ammunition in the armed forces inventory which is manufactured in a limited number of countries in the world. Before application of this study, the welding process of the product could not be carried out in a systematic way. The process was conducted by trialand- error approach by changing input parameter values at each operation. This caused a lot of costs. With the help of this study, best parameter combination is found, tested, validated with ANNs and operation costs are minimized by 30%.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
26049. Welfare effects of housing price appreciation in an economy with binding credit constraints
- Creator:
- Tsharakyan, Ashot, Univerzita Karlova. Centrum pro ekonomický výzkum a doktorské studium, and Národohospodářský ústav (Akademie věd ČR)
- Publisher:
- CERGE-EI
- Format:
- electronic and 53 s.
- Type:
- model:monograph and TEXT
- Subject:
- Regionální ekonomie, regionální ekonomika, Kombinatorika. Teorie grafů. Matematická statistika. Operační výzkum. Matematické modelování, bohatství, ceny, matematické modelování, trh nemovitostí, 332.72, 338.5, 364.668, 519.673, (048.8), 4, 13, 332, and 519.1/.8
- Language:
- English
- Description:
- Ashot Tsharakyan. and born digital
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
26050. Welfare effects of labor migration
- Creator:
- Vikhrov, Dmytro, Univerzita Karlova. Centrum pro ekonomický výzkum a doktorské studium, and Národohospodářský ústav (Akademie věd ČR)
- Publisher:
- CERGE-EI
- Format:
- electronic and 33 s. : il.
- Type:
- model:monograph and TEXT
- Subject:
- Práce, pracovní migrace, migrační politika, modelování a simulace, labor migration, migration policy, modeling and simulation, 331.556, 314.15:323.1, 519.86/.87, (048.8), 4, and 331
- Language:
- English and Czech
- Description:
- Dmytro Vikhrov., Obsahuje bibliografii a bibliografické odkazy, České resumé, and born digital
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public