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Hamilton
Terms modified by Hamilton Selected AbstractsRICHARD HAMILTON AT THE IDEAL HOME EXHIBITION OF 1958: GALLERY FOR A COLLECTOR OF BRUTALIST AND TACHISTE ARTART HISTORY, Issue 5 2007BEN HIGHMOREArticle first published online: 2 NOV 200 This essay develops a close reading of Richard Hamilton's Gallery for a Collector of Brutalist and Tachiste Art, his contribution to the Daily Mail's Ideal Home Exhibition of 1958. Included in the Gallery for a Collector was Hamilton's 1957 painting Hommage à Chrysler Corp. The essay treats both the gallery and the painting as ,meta-aesthetic' practices that register something of the aesthetic historicity of their social and cultural moment. To demonstrate how the work relates to the historicity of perception (sensorial, social and political perception) and to the material culture of the time, the essay sets out a number of possible contexts for attending to the painting and the Ideal Home installation. [source] Platelet-derived growth factors in the developing avian heart and maturating coronary vasculatureDEVELOPMENTAL DYNAMICS, Issue 4 2005Nynke M.S. Abstract Platelet-derived growth factors (PDGFs) are important in embryonic development. To elucidate their role in avian heart and coronary development, we investigated protein expression patterns of PDGF-A, PDGF-B, and the receptors PDGFR-, and PDGFR-, using immunohistochemistry on sections of pro-epicardial quail,chicken chimeras of Hamburger and Hamilton (HH) 28,HH35. PDGF-A and PDGFR-, were expressed in the atrial septum, sinus venosus, and throughout the myocardium, with PDGFR-, retreating to the trabeculae at later stages. Additionally, PDGF-A and PDGFR-, were present in outflow tract cushion mesenchyme and myocardium, respectively. Small cardiac nerves and (sub)epicardial cells expressed PDGF-B and PDGFR-,. Furthermore, endothelial cells expressed PDGF-B, while vascular smooth muscle cells and interstitial epicardium-derived cells expressed PDGFR-,, indicating a role in coronary maturation. PDGF-B is also present in ventricular septal development, in the absence of any PDGFR. Epicardium-derived cells in the atrioventricular cushions expressed PDGFR-,. We conclude that all four proteins are involved in myocardial development, whereas PDGF-B and PDGFR-, are specifically important in coronary maturation. Developmental Dynamics 233:1579,1588, 2005. © 2005 Wiley-Liss, Inc. [source] Factors affecting the reproductive biology of Melittobia digitata and failure to meet the sex ratio predictions of Hamilton's local mate competition theoryENTOMOLOGIA EXPERIMENTALIS ET APPLICATA, Issue 1 2003M.F. Cooperband Abstract Melittobia digitata Dahms (Eulophidae, Tetrastichini), a species of parasitic wasp satisfying all of Hamilton's local mate competition requisites, does not exhibit the predicted change in sex ratio with increased foundress number. A multifactorial design was used to test how age, oviposition experience, feeding experience, mating, and foundress number affect host-acceptance, number of offspring, and sex ratio of this species developing on honey bee pupae, Apis mellifera (L.) (Apidae, Apini). All factors significantly affected the time it took for oviposition to commence. Females oviposited soonest when they were 2 days old, mated, had previous feeding and oviposition experience, and were placed on hosts with multiple foundresses. Although the age difference between 2- and 5-day-old females is small, it significantly affected reproductive behavior. Age, mating, and foundress number were found to have an effect on sex ratio, however, the foundress effect was found to be a mathematical artifact of the limited host size. After correcting for this variable, females were found to have a constant sex ratio of approximately 0.05. Several 2-way interactions between factors were revealed: age and experience, age and foundress number, age and mating, foundress number and experience, and foundress number and mating. One 3-way interaction was found between age, mating, and foundress number. This study demonstrates that the sex ratio of M. digitata is not altered with increased foundresses, as predicted by Hamilton, and that slight changes in preconditioning may modify reproductive behavior. [source] Dissolved fraction of standard laboratory cladoceran food alters toxicity of waterborne silver to Ceriodaphnia dubia,ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 6 2008Jason M. Kolts Abstract The biotic ligand model (BLM) for the acute toxicity of cationic metals to aquatic organisms incorporates the toxicity-modifying effects of dissolved organic matter (DOM), but the default parameterization (i.e., assuming 10% of DOM is humic acid) does not differentiate DOM from different sources. We exposed a cladoceran (Ceriodaphnia dubia) to Ag in the presence of DOM from filtered YCT (standard yeast,Cerophyll®,trout chow food recommended by the U.S. Environmental Protection Agency [EPA] for cladocerans), from the Suwannee River (GA, USA; relatively little anthropogenic input), and from the Desjardins Canal in Hamilton (ON, Canada; receives treated municipal wastewater effluent). In all three treatments, the dissolved organic carbon (DOC) concentration was 2 mg/L (the concentration following addition of YCT slurry at the U.S. EPA,recommended volume ratio). The average 48-h median effects concentration (EC50) ratios for dissolved Ag in the presence and absence of DOM [i.e., (EC50 with DOM)/(EC50 without DOM)] were as follows: Suwannee River, 1.6; Desjardins Canal, 2.2; and YCT filtrate, 26.8. Therefore, YCT filtrate provided much more protection against Ag toxicity than that provided by DOM from the surface waters. The major spectral characteristic that differentiated YCT filtrate from the other two types of DOM was a strong tryptophan peak in the excitation,emission matrix for YCT. These results have important implications for interpreting Ag toxicity tests in which organisms are fed YCT, and they suggest BLM-calculated toxicity predictions might be improved by incorporating specific chemical constituents or surrogate indices of DOM. Another component of the protective effect against Ag toxicity, however, might be that the dissolved fraction of YCT served as an energy and/or nutrient source for C. dubia. [source] HAMILTON'S FORCES OF NATURAL SELECTION AFTER FORTY YEARSEVOLUTION, Issue 6 2007Michael R. Rose In 1966, William D. Hamilton published a landmark paper in evolutionary biology: "The Moulding of Senescence by Natural Selection." It is now apparent that this article is as important as his better-known 1964 articles on kin selection. Not only did the 1966 article explain aging, it also supplied the basic scaling forces for natural selection over the entire life history. Like the Lorentz transformations of relativistic physics, Hamilton's Forces of Natural Selection provide an overarching framework for understanding the power of natural selection at early ages, the existence of aging, the timing of aging, the cessation of aging, and the timing of the cessation of aging. His twin Forces show that natural selection shapes survival and fecundity in different ways, so their evolution can be somewhat distinct. Hamilton's Forces also define the context in which genetic variation is shaped. The Forces of Natural Selection are readily manipulable using experimental evolution, allowing the deceleration or acceleration of aging, and the shifting of the transition ages between development, aging, and late life. For these reasons, evolutionary research on the demographic features of life history should be referred to as "Hamiltonian." [source] Culture-based fisheries in non-perennial reservoirs in Sri Lanka: production and relative performance of stocked speciesFISHERIES MANAGEMENT & ECOLOGY, Issue 4 2005W. M. H. K. WIJENAYAKE Abstract, In Sri Lanka, there is a great potential for the development of culture-based fisheries because of the availability of around 12 000 non-perennial reservoirs in the dry zone (<187 cm annual rainfall) of the island. These reservoirs fill during the north-east monsoonal period in October to December and almost completely dry up during August to October. As these non-perennial reservoirs are highly productive, hatchery-reared fish fingerlings can be stocked to develop culture-based fisheries during the water retention period of 7,9 months. The present study was conducted in 32 non-perennial reservoirs in five administrative districts in Sri Lanka. These reservoirs were stocked with fingerlings of Indian (catla Catla catla Hamilton and rohu Labeo rohita Hamilton) and Chinese (bighead carp Aristichthys nobilis Richardson) major carps, common carp Cyprinus carpio L., genetically improved farmed tilapia (GIFT) strain of Nile tilapia, Oreochromis niloticus (L.) and post-larvae of giant freshwater prawn, Macrobrachium rosenbergii De Man, at three different species combinations and overall stocking densities (SD) ranging from 218 to 3902 fingerlings ha,1, during the 2002,2003 culture cycle. Of the 32 reservoirs stocked, reliable data on harvest were obtained from 25 reservoirs. Fish yield ranged from 53 to 1801 kg ha,1 and the yields of non-perennial reservoirs in southern region were significantly (P < 0.05) higher than those in the northern region. Naturally-recruited snakehead species contributed the catches in northern reservoirs. Fish yield was curvilinearly related to reservoir area (P < 0.05), and a negative second order relationship was evident between SD and yield (P < 0.05). Chlorophyll- a and fish yield exhibited a positive second order relationship (P < 0.01). Bighead carp yield impacted positively on the total yield (P < 0.05), whereas snakehead yield impact was negative. Bighead carp, common carp and rohu appear suitable for poly-culture in non-perennial reservoirs. GIFT strain O. niloticus had the lowest specific growth rate among stocked species and freshwater prawn had a low return. [source] Population genetic studies of hilsa shad, Tenualosa ilisha (Hamilton), in Bangladesh waters: evidence for the existence of separate gene poolsFISHERIES MANAGEMENT & ECOLOGY, Issue 5 2000M. Rahman Hilsa shad, Tenualosa ilisha (Hamilton), in Bangladesh is found in inland rivers, estuaries and the marine environment, throughout the year, but the peak catch period is during upstream migration. Tissue (white muscle, liver, brain) samples (total 640 specimens) were collected from three different localities, representing marine, brackish and fresh water, during the monsoon in the summer of the years 1993,1996 to identify genetic markers and study the population structure of this species. The samples were analysed by starch gel electrophoresis and isoelectric focusing, and stained for 15 enzymes and general muscle proteins. Only phosphoglucomutase, aspartate amino transferase, esterase and unidentified muscle proteins were found to be polymorphic. The allele frequencies for the samples collected in the marine environment deviated from corresponding samples from freshwater and estuarine localities, indicating that hilsa shad in Bangladesh waters comprise more than one gene pool. [source] Population Synthesis: Comparing the Major Techniques Using a Small, Complete Population of FirmsGEOGRAPHICAL ANALYSIS, Issue 2 2009Justin Ryan Recently, disaggregate modeling efforts that rely on microdata have received wide attention by scholars and practitioners. Synthetic population techniques have been devised and are used as a viable alternative to the collection of microdata that normally are inaccessible because of confidentiality concerns or incomplete because of high acquisition costs. The two most widely discussed synthetic techniques are the synthetic reconstruction method (IPFSR), which makes use of iterative proportional fitting (IPF) techniques, and the combinatorial optimization (CO) method. Both methods are described in this article and then evaluated in terms of their ability to recreate a known population of firms, using limited data extracted from the parent population of the firms. Testing a synthetic population against a known population is seldom done, because obtaining an entire population usually is too difficult. The case presented here uses a small, complete population of firms for the City of Hamilton, Ontario, for the year 1990; firm attributes compiled are number of employees, 3-digit standard industrial classification, and geographic location. Results are summarized for experiments based upon various combinations of sample size and tabulation detail designed to maximize the accuracy of resulting synthetic populations while holding input data costs to a minimum. The output from both methods indicates that increases in sample size and tabulation detail result in higher quality synthetic populations, although the quality of the generated population is more sensitive to increases in tabular detail. Finally, most tests conducted with the created synthetic populations suggest that the CO method is superior to the IPFSR method. Los modelos desagregados basados en micro data han recibido la atención relativamente reciente de los círculos académicos y de aplicación. La colección de dicha data es una tarea difícil por cuestiones de accesibilidad, confidencialidad, datos incompletos o altos costos de adquisición. Por esta razón se han creado indicadores sintéticos como a alternativa a la recolección directa de datos. Los dos indicadores sintéticos mas discutidos/conocidos son el método de Reconstrucción Sintética (Sytnthetic Reconstruction method) (IPFSR) que hace uso de técnicas de Ajuste Proporcional Iterativo (IPF); y el método Optimización Combinatoria (CO). Ambos métodos son descritos en este artículo y luego evaluados en base a su habilidad de recrear una población de empresas ya conocidas o preestablecidas. Contrastar una población sintética versus una población conocida es una operación poco frecuente porque la obtención de una población entera es por lo general bastante difícil. El caso presentado en este estudio utiliza una población pequeña y completa de empresas en la ciudad de Hamilton, Ontario (Canadá) para el año 1990. Las variables recopiladas son el número de empleados, SIC (código estandarizado de clasificación industrial), y ubicación geográfica. Los resultados que se reportan en el presente estudio son producto de varios experimentos basados en varias combinaciones del tamaño de la muestra, y del detalle en la tabulación diseñados, los mismos que fueron diseñados para maximizar la exactitud de las poblaciones sintéticas calculadas y al mismo tiempo minimizar los costos de datos necesarios. Los resultados obtenidos por ambos métodos indica que los incrementos en el tamaño de la muestra y en el detalle de la tabulación resultan en un estimado de poblaciones mejor, aunque este estimado es particularmente sensible a incrementos en el detalle de las tabulaciones. Finalmente, la mayoría de pruebas realizadas con las poblaciones sintéticas generadas para este estudio sugieren que el método CO es superior al método IPFSR. [source] Ballenger's otorhinolaryngology head and neck surgery, 16th edition by James B. Snow, Jr, and John Jacob Ballenger, BC Decker, Inc., Hamilton, Ontario, Canada, 2003, 1616 ppHEAD & NECK: JOURNAL FOR THE SCIENCES & SPECIALTIES OF THE HEAD AND NECK, Issue 11 2004M. Boyd Gillespie MD No abstract is available for this article. [source] Bond rolling resistance and its effect on yielding of bonded granulates by DEM analysesINTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS, Issue 8 2006M. J. Jiang Abstract A discrete element modelling of bonded granulates and investigation on the bond effect on their behaviour are very important to geomechanics. This paper presents a two-dimensional (2-D) discrete element theory for bonded granulates with bond rolling resistance and provides a numerical investigation into the effect of bond rolling resistance on the yielding of bonded granulates. The model consists of mechanical contact models and equations governing the motion of bonded particles. The key point of the theory is that the assumption in the original bond contact model previously proposed by the authors (55th CSCE-ASCE Conference, Hamilton, Ont., Canada, 2002; 313,320; J. Eng. Mech. (ASCE) 2005; 131(11):1209,1213) that bonded particles are in contact at discrete points, is here replaced by a more reliable assumption that bonded particles are in contact over a width. By making the idealization that the bond contact width is continuously distributed with the normal/tangential basic elements (BE) (each BE is composed of spring, dashpot, bond, slider or divider), we establish a bond rolling contact model together with bond normal/tangential contact models, and also relate the governing equations to local equilibrium. Only one physical parameter , needs to be introduced in the theory in comparison to the original bond discrete element model. The model has been implemented into a 2-D distinct element method code, NS2D. Using the NS2D, a total of 86 1-D, constant stress ratio, and biaxial compressions tests have been carried out on the bonded granular samples of different densities, bonding strengths and rolling resistances. The numerical results show that: (i) the new theory predicts a larger internal friction angle, a larger yielding stress, more brittle behaviour and larger final broken contact ratio than the original bond model; (ii) the yielding stress increases nonlinearly with the increasing value of ,, and (iii) the first-yield curve (initiation of bond breakage), which define a zone of none bond breakage and which shape and size are affected by the material density, is amplified by the bond rolling resistance in analogous to that predicted by the original bond model. Copyright © 2006 John Wiley & Sons, Ltd. [source] A structural optimization method based on the level set method using a new geometry-based re-initialization schemeINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 12 2010Shintaro Yamasaki Abstract Structural optimization methods based on the level set method are a new type of structural optimization method where the outlines of target structures can be implicitly represented using the level set function, and updated by solving the so-called Hamilton,Jacobi equation based on a Eulerian coordinate system. These new methods can allow topological alterations, such as the number of holes, during the optimization process whereas the boundaries of the target structure are clearly defined. However, the re-initialization scheme used when updating the level set function is a critical problem when seeking to obtain appropriately updated outlines of target structures. In this paper, we propose a new structural optimization method based on the level set method using a new geometry-based re-initialization scheme where both the numerical analysis used when solving the equilibrium equations and the updating process of the level set function are performed using the Finite Element Method. The stiffness maximization, eigenfrequency maximization, and eigenfrequency matching problems are considered as optimization problems. Several design examples are presented to confirm the usefulness of the proposed method. Copyright © 2010 John Wiley & Sons, Ltd. [source] Piecewise constant level set method for structural topology optimizationINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 4 2009Peng Wei Abstract In this paper, a piecewise constant level set (PCLS) method is implemented to solve a structural shape and topology optimization problem. In the classical level set method, the geometrical boundary of the structure under optimization is represented by the zero level set of a continuous level set function, e.g. the signed distance function. Instead, in the PCLS approach the boundary is described by discontinuities of PCLS functions. The PCLS method is related to the phase-field methods, and the topology optimization problem is defined as a minimization problem with piecewise constant constraints, without the need of solving the Hamilton,Jacobi equation. The result is not moving the boundaries during the iterative procedure. Thus, it offers some advantages in treating geometries, eliminating the reinitialization and naturally nucleating holes when needed. In the paper, the PCLS method is implemented with the additive operator splitting numerical scheme, and several numerical and procedural issues of the implementation are discussed. Examples of 2D structural topology optimization problem of minimum compliance design are presented, illustrating the effectiveness of the proposed method. Copyright © 2008 John Wiley & Sons, Ltd. [source] A partition-of-unity-based finite element method for level setsINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 10 2008Stéphane Valance Abstract Level set methods have recently gained much popularity to capture discontinuities, including their possible propagation. Typically, the partial differential equations that arise in level set methods, in particular the Hamilton,Jacobi equation, are solved by finite difference methods. However, finite difference methods are less suited for irregular domains. Moreover, it seems slightly awkward to use finite differences for the capturing of a discontinuity, while in a subsequent stress analysis finite elements are normally used. For this reason, we here present a finite element approach to solving the governing equations of level set methods. After a review of the governing equations, the initialization of the level sets, the discretization on a finite domain, and the stabilization of the resulting finite element method will be discussed. Special attention will be given to the proper treatment of the internal boundary condition, which is achieved by exploiting the partition-of-unity property of finite element shape functions. Finally, a quantitative analysis including accuracy analysis is given for a one-dimensional example and a qualitative example is given for a two-dimensional case with a curved discontinuity. Copyright © 2008 John Wiley & Sons, Ltd. [source] An assumed-gradient finite element method for the level set equationINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 8 2005Hashem M. Mourad Abstract The level set equation is a non-linear advection equation, and standard finite-element and finite-difference strategies typically employ spatial stabilization techniques to suppress spurious oscillations in the numerical solution. We recast the level set equation in a simpler form by assuming that the level set function remains a signed distance to the front/interface being captured. As with the original level set equation, the use of an extensional velocity helps maintain this signed-distance function. For some interface-evolution problems, this approach reduces the original level set equation to an ordinary differential equation that is almost trivial to solve. Further, we find that sufficient accuracy is available through a standard Galerkin formulation without any stabilization or discontinuity-capturing terms. Several numerical experiments are conducted to assess the ability of the proposed assumed-gradient level set method to capture the correct solution, particularly in the presence of discontinuities in the extensional velocity or level-set gradient. We examine the convergence properties of the method and its performance in problems where the simplified level set equation takes the form of a Hamilton,Jacobi equation with convex/non-convex Hamiltonian. Importantly, discretizations based on structured and unstructured finite-element meshes of bilinear quadrilateral and linear triangular elements are shown to perform equally well. Copyright © 2005 John Wiley & Sons, Ltd. [source] Mixed ,2/,, nonlinear filteringINTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL, Issue 4 2009M. D. S. Aliyu Abstract In this paper, we consider the mixed ,2/,, filtering problem for affine nonlinear systems. Sufficient conditions for the solvability of this problem with a finite-dimensional filter are given in terms of a pair of coupled Hamilton,Jacobi,Isaacs equations (HJIEs). For linear systems, it is shown that these conditions reduce to a pair of coupled Riccati equations similar to the ones for the control case. Both the finite-horizon and the infinite-horizon problems are discussed. Simulation results are presented to show the usefulness of the scheme, and the results are generalized to include other classes of nonlinear systems. Copyright © 2008 John Wiley & Sons, Ltd. [source] Robust tracking control for a class of MIMO nonlinear systems with measurable output feedbackINTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL, Issue 1 2008Ya-Jun Pan Abstract This paper proposes a robust output feedback controller for a class of nonlinear systems to track a desired trajectory. Our main goal is to ensure the global input-to-state stability (ISS) property of the tracking error nonlinear dynamics with respect to the unknown structural system uncertainties and external disturbances. Our approach consists of constructing a nonlinear observer to reconstruct the unavailable states, and then designing a discontinuous controller using a back-stepping like design procedure to ensure the ISS property. The observer design is realized through state transformation and there is only one parameter to be determined. Through solving a Hamilton,Jacoby inequality, the nonlinear control law for the first subsystem specifies a nonlinear switching surface. By virtue of nonlinear control for the first subsystem, the resulting sliding manifold in the sliding phase possesses the desired ISS property and to certain extent the optimality. Associated with the new switching surface, the sliding mode control is applied to the second subsystem to accomplish the tracking task. As a result, the tracking error is bounded and the ISS property of the whole system can be ensured while the internal stability is also achieved. Finally, an example is presented to show the effectiveness of the proposed scheme. Copyright © 2007 John Wiley & Sons, Ltd. [source] Some nonlinear optimal control problems with closed-form solutionsINTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL, Issue 14 2001Michael Margaliot Abstract Optimal controllers guarantee many desirable properties including stability and robustness of the closed-loop system. Unfortunately, the design of optimal controllers is generally very difficult because it requires solving an associated Hamilton,Jacobi,Bellman equation. In this paper we develop a new approach that allows the formulation of some nonlinear optimal control problems whose solution can be stated explicitly as a state-feedback controller. The approach is based on using Young's inequality to derive explicit conditions by which the solution of the associated Hamilton,Jacobi,Bellman equation is simplified. This allows us to formulate large families of nonlinear optimal control problems with closed-form solutions. We demonstrate this by developing optimal controllers for a Lotka,Volterra system. Copyright © 2001 John Wiley & Sons, Ltd. [source] H, control for nonlinear affine systems: a chain-scattering matrix description approachINTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL, Issue 4 2001Jang-Lee Hong Abstract This paper combines an alternative chain-scattering matrix description with (J, J,)-lossless and a class of conjugate (,J, ,J,)-lossless systems to design a family of nonlinear H, output feedback controllers. The present systems introduce a new chain-scattering setting, which not only offers a clearer expression for the solving process of the nonlinear H, control problem but also removes the fictitious signals introduced by the traditional chain-scattering approach. The intricate nonlinear affine control problem thus can be transformed into a simple lossless network and is easy to deal with in a network-theory context. The relationship among these (J, J,) systems, L2 -gain, and Hamilton,Jacobi equations is also given. Block diagrams are used to illustrate the central theme. Copyright © 2001 John Wiley & Sons, Ltd. [source] Three-dimensional nonlinear H, guidance lawINTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL, Issue 2 2001Ciann-Dong Yang Abstract This paper proposes a novel three-dimensional missile guidance law design based on nonlinear H, control. The complete nonlinear kinematics of pursuit,evasion motion is considered in the three-dimensional spherical co-ordinates system; neither linearization nor small angle assumption is made here. The nonlinear H, guidance law is expressed in a simple form by solving the associated Hamilton,Jacobi partial differential inequality analytically. Unlike adaptive guidance laws, the implement of the proposed robust H, guidance law does not require the information of target acceleration, while ensuring acceptable interceptive performance for arbitrary target with finite acceleration. The resulting pursuit,evasion trajectories for both the H, -guided missile and the worst-case target are determined in closed form, and the performance robustness against variations in target acceleration, in engagement condition, and in control loop gain, is verified by numerical simulations. Copyright © 2001 John Wiley & Sons, Ltd. [source] Sleeping Giant: Awakening the Transatlantic Services Economy , Edited by D.S. Hamilton and J.P. QuinlanJCMS: JOURNAL OF COMMON MARKET STUDIES, Issue 3 2009HOLLY JARMAN No abstract is available for this article. [source] Patterning of the axial musculature in the developing chick embryo (Gallus)JOURNAL OF ANATOMY, Issue 5 2002P. J. Adds While the development and patterning events of the skeletal, myogenic and connective tissues of the developing limb buds of the chick have been relatively well studied, there is little known about the formation of the epaxial muscles and tendons. The epaxial muscles form the postvertebral muscle groups and develop from the myotome of the somite. The myotome develops from myogenic precursors migrating from the dorsomedial lip of the dermomyotome. These myogenic cells differentiate in a cranial to caudal sequence with the muscle fibres also orientated in a cranial to caudal direction. Here we use immunohistological staining both in whole mount and in transverse sections of chick embryos from various stages of development. Antibodies to the myosin heavy chain or tenascin were used to visualise the development of the epaxial muscles and tendons. The first myotomal muscle fibres are differentiated by Hamburger and Hamilton (H & H) stage 10 in the cranial somites, and differentiation proceeds caudally until at least H & H stage 22,23. Further development of the epaxial muscles does not take place until H & H stage 26,27 with the splitting of the myotome into the individual muscles. We demonstrate how the myotome splits into the individual muscles and how some muscle fibres become reorientated into a more oblique orientation. This delayed development and reorientation of muscle fibres is unique to the epaxial muscles. [source] Dietary arginine requirement of fingerling Indian major carp, Labeo rohita (Hamilton) based on growth, nutrient retention efficiencies, RNA/DNA ratio and body compositionJOURNAL OF APPLIED ICHTHYOLOGY, Issue 6 2009S. F. Abidi Summary To quantify the optimum dietary arginine requirement of fingerling Indian major carp, Labeo rohita (4.10 ± 0.04 cm; 0.62 ± 0.02 g), an 8-week growth trial was conducted in eighteen 70-L indoor circular aqua-coloured troughs provided with a flow-through system at 28 ± 1°C. Isonitrogenous (40 g 100 g,1 crude protein) and isocaloric (4.28 kcal g,1 gross energy) amino acid test diets containing casein and gelatin as intact protein sources with graded levels of arginine (0.5, 0.75, 1.0, 1.25, 1.50 and 1.75 g 100 g,1 dry diet) were fed to triplicate groups of fish to apparent satiation at 07:00, 12:00 and 17:30 hours. Growth performance of fish fed the above diets was evaluated on the basis of absolute weight gain (AWG), specific growth rate (SGR), feed conversion ratio (FCR), protein efficiency ratio (PER), protein retention efficiency (PRE) and energy retention efficiency (ERE). Maximum AWG (2.61), SGR (2.80), best FCR (1.35), highest PER (1.85), PRE (37%) and ERE (76%) were recorded at 1.25 g 100 g,1 dietary arginine. Maximum body protein (18.88 g 100 g,1) and RNA/DNA ratio (5.20) were also obtained in a 1.25 g 100 g,1 arginine dry diet. Except for the reduced growth performance in fish fed arginine-deficient diets, no other deficiency signs were apparent. Based on the broken-line and second-degree polynomial regression analysis of the AWG, SGR, FCR, PER, PRE and ERE data, the optimum arginine requirement for fingerling Labeo rohita was found to be in the range of 1.22,1.39 g 100 g,1 of the dry diet, corresponding to 3.05,3.47 g 100 g,1 of dietary protein. [source] Nutritional evaluation of fermented black gram (Phaseolus mungo) seed meal in compound diets for rohu, Labeo rohita (Hamilton), fingerlingsJOURNAL OF APPLIED ICHTHYOLOGY, Issue 1 2007S. Ramachandran Summary Six isonitrogenous (approximately 35% crude protein) and isocaloric (approximately 4.0 kcal g,1) diets were formulated incorporating raw and fermented black gram, Phaseolus mungo, seed meal at 20%, 30% and 40% levels by weight into a fishmeal-based control diet fed to rohu, Labeo rohita, fingerlings (mean weight, 1.81 ± 0.21 g) for 80 days for a study of fish performance. A particular bacterial strain (Bacillus sp.) isolated from the intestine of adult common carp (Cyprinus carpio) reared in the wild having significant amylolytic, cellulolytic, lipolytic and proteolytic activities was used for fermentation of seed meal for 15 days at 37 ± 2°C. Fermentation of P. mungo seed meal was effective in significantly reducing the crude fibre content and antinutritional factors such as tannins and phytic acid, and enhancing available free amino acids and fatty acids. In terms of growth, feed conversion ratio and protein efficiency ratio, the 30% fermented black gram seed meal incorporated diet resulted in a significantly (P < 0.05) better performance of rohu fingerlings. In general, growth and feed utilization efficiencies of diets containing fermented seed meal were superior to diets containing raw seed meal. The apparent protein digestibility (APD) values decreased with increasing levels of raw seed meal in the diets. The APD for raw seed meal was lower at all levels of inclusion in comparison to those for the fermented seed meals. The maximum deposition of protein in the carcass was recorded in fish fed the diet containing 40% fermented seed meal. The results indicate that fermented black gram seed meal can be incorporated in carp diets up to the 30% level compared to the 10% level of raw seed meal. [source] Effects of amino acid supplementation on the nutritive quality of fermented linseed meal protein in the diets for rohu, Labeo rohita, fingerlingsJOURNAL OF APPLIED ICHTHYOLOGY, Issue 5 2001N. Mukhopadhyay A feeding trial was conducted for 8 weeks to examine the effects of partial substitution of fish meal (FM) protein (crude protein content: 58.5%) with linseed meal protein with and without supplemental amino acids in diets for rohu Labeo rohita (Hamilton), fingerlings (mean weight: 1.50 ± 0.3 g). Prior to incorporation into the diets, linseed meal was fermented with lactic acid bacteria (Lactobacillus acidophilus) to reduce/eliminate the antinutritional tannin and phytic acid factors. Twelve experimental diets (diets D1,D12) were formulated to replace the FM protein from a reference diet (RD) with linseed meal protein at different levels (four sets of diets, of which each set of three diets contained 25%, 50% and 75% replacement of FM protein by linseed meal protein, respectively). Diets D1,D3 were not supplemented with any amino acid. Lysine was supplemented in diets D4,D6. Diets D7,D9 were supplemented with methionine + cystine (together), and diets D10,D12 contained lysine and methionine + cystine (together). Lysine and methionine + cystine (together) were added to the diets at 5.7% and 3.1% of dietary protein, respectively. The groups of fish fed diets without amino acid supplementation had significantly lower percentages of weight gain, specific growth rate and high feed : gain ratio than the fish groups fed other experimental diets. The addition of lysine and methionine + cystine to the diet in which 50% of the FM protein was replaced by linseed meal protein (diet D11) significantly improved fish performance. The results of the present study suggest that rohu fingerlings can effectively utilize the supplemented amino acids and that linseed meal protein can replace up to 50% of the FM protein in rohu diets if the linseed meal is properly processed (fermented) and supplemented with the lacking amino acids. [source] Examining a Gender Stereotype: Menopausal Women,JOURNAL OF APPLIED SOCIAL PSYCHOLOGY, Issue 4 2001Amy Marcus-Newhall Two studies evaluated whether there was a subtype of menopausal women and, if so, how it differed from the global gender stereotype. Study 1 had participants generate items associated with women going through menopause, midlife women, and midlife men. Results showed that there is a menopausal women stereotype, and it is mostly negative in content. Moreover, this stereotype differs from the perceptions of women in general. Study 2 examined the effects of the menopausal women stereotype by employing the illusory correlation paradigm (e.g., McConnell, Sherman, & Hamilton, 1994) and found that participants greatly overestimated the number of times that menopausal women and negative moods appeared together. This research highlights the importance of examining stereotype subtypes and subgroups [source] Device-Related Infection Among Patients With Pacemakers and Implantable Defibrillators: Incidence, Risk Factors, and ConsequencesJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 7 2010PABLO B. NERY M.D. Risk Factors and Complications of Pacemaker and ICD Infection.,Background: Device-related infection is a major limitation of device therapy for cardiac arrhythmia. Methods: The authors analyzed the incidence and risk factors for cardiac device infection (CDI) among consecutive patients implanted with pacemaker (PM) or implantable cardioverter defibrillator (ICD) (including cardiac resynchronization therapy devices) at a tertiary health center in Hamilton, Ontario, Canada. Most patients with device-related infections were identified by an internal infection control system that reports any positive wound and blood cultures following surgery, between 2005 and the present. A retrospective review of patient records was also performed for all patients who received an ICD or PM between July 1, 2003 and March 20, 2007. Results: A total of 24 infections were identified among 2,417 patients having device surgery (1%). Fifteen of these infections (60%) were diagnosed within 90 days of the last surgical procedure. Univariate analysis showed that patients presenting with CDI were more likely to have had a device replacement, rather than a new implant, had more complex devices (dual/triple chamber vs single), and were more likely to have had a prior lead dislodgement. Multivariate analysis found device replacement (P = 0.02) and cardiac resynchronization therapy (CRT)/dual-chamber devices (P = 0.048) to be independent predictors of infection. One patient developed septic pulmonary emboli after having laser-assisted lead extraction. No patient died and 22 patients received a new device. Conclusion: CDI occurs in about 1% of cases in high volume facilities. Pulse generator replacement surgery and dual- or triple-chamber device implantation were associated with a significantly increased risk of infection. (J Cardiovasc Electrophysiol, Vol. pp. 786-790, July 2010) [source] The group selection controversyJOURNAL OF EVOLUTIONARY BIOLOGY, Issue 1 2010E. G. LEIGH Jr Abstract Many thought Darwinian natural selection could not explain altruism. This error led Wynne-Edwards to explain sustainable exploitation in animals by selection against overexploiting groups. Williams riposted that selection among groups rarely overrides within-group selection. Hamilton showed that altruism can evolve through kin selection. How strongly does group selection influence evolution? Following Price, Hamilton showed how levels of selection interact: group selection prevails if Hamilton's rule applies. Several showed that group selection drove some major evolutionary transitions. Following Hamilton's lead, Queller extended Hamilton's rule, replacing genealogical relatedness by the regression on an actor's genotypic altruism of interacting neighbours' phenotypic altruism. Price's theorem shows the generality of Hamilton's rule. All instances of group selection can be viewed as increasing inclusive fitness of autosomal genomes. Nonetheless, to grasp fully how cooperation and altruism evolve, most biologists need more concrete concepts like kin selection, group selection and selection among individuals for their common good. [source] Reproductive value in a complex life cycle: heat tolerance of the pitcher-plant mosquito, Wyeomyia smithiiJOURNAL OF EVOLUTIONARY BIOLOGY, Issue 1 2005P. A. Zani Abstract Because mortality accumulates with age, Fisher proposed that the strength of selection acting on survival should increase from birth up to the age of first reproduction. Hamilton later theorized that the strength of selection acting on survival should not change from birth to age at first reproduction. As organisms in nature do not live in uniform environments but, rather, experience periodic stress, we hypothesized that resistance to environmental stress should increase (Fisher) or remain constant (Hamilton) from birth to age at first reproduction. Using the pitcher-plant mosquito, Wyeomyia smithii, we imposed heat stress by simulating the passage of a warm-weather front at different preadult and adult stages. Contrary to either Fisher or Hamilton, stress tolerance declined from embryos to larvae to pupae to adults. Consequently, reproductive value appears to have been of little consequence in the evolution of stage-specific tolerance of heat stress in W. smithii. [source] Husbandry stress exacerbates mycobacterial infections in adult zebrafish, Danio rerio (Hamilton)JOURNAL OF FISH DISEASES, Issue 11 2009J M Ramsay Abstract Mycobacteria are significant pathogens of laboratory zebrafish, Danio rerio (Hamilton). Stress is often implicated in clinical disease and morbidity associated with mycobacterial infections but has yet to be examined with zebrafish. The aim of this study was to examine the effects of husbandry stressors on zebrafish infected with mycobacteria. Adult zebrafish were exposed to Mycobacterium marinum or Mycobacterium chelonae, two species that have been associated with disease in zebrafish. Infected fish and controls were then subjected to chronic crowding and handling stressors and examined over an 8-week period. Whole-body cortisol was significantly elevated in stressed fish compared to non-stressed fish. Fish infected with M. marinum ATCC 927 and subjected to husbandry stressors had 14% cumulative mortality while no mortality occurred among infected fish not subjected to husbandry stressors. Stressed fish, infected with M. chelonae H1E2 from zebrafish, were 15-fold more likely to be infected than non-stressed fish at week 8 post-injection. Sub-acute, diffuse infections were more common among stressed fish infected with M. marinum or M. chelonae than non-stressed fish. This is the first study to demonstrate an effect of stress and elevated cortisol on the morbidity, prevalence, clinical disease and histological presentation associated with mycobacterial infections in zebrafish. Minimizing husbandry stress may be effective at reducing the severity of outbreaks of clinical mycobacteriosis in zebrafish facilities. [source] Experimental exposure of zebrafish, Danio rerio (Hamilton), to Mycobacterium marinum and Mycobacterium peregrinum reveals the gastrointestinal tract as the primary route of infection: a potential model for environmental mycobacterial infectionJOURNAL OF FISH DISEASES, Issue 10 2007M J Harriff Abstract The natural route by which fish become infected with mycobacteria is unknown. Danio rerio (Hamilton) were exposed by bath immersion and intubation to Mycobacterium marinum and Mycobacterium peregrinum isolates obtained from diseased zebrafish. Exposed fish were collected over the course of 8 weeks and examined for the presence of mycobacteriosis. Mycobacteria were consistently cultured from the intestines, and often from the livers and spleens of fish exposed by both methods. Mycobacteria were not observed in the gills. Histological analysis revealed that fish infected with M. marinum often developed granulomas accompanied by clinical signs of mycobacteriosis, while infection with M. peregrinum infrequently led to clinical signs of disease. Passage of the bacteria through environmental amoebae (Acanthamoeba castellani) was associated with increased growth of M. peregrinum over the course of 8 weeks, when compared to infection with the bacteria not passed through amoebae. The results provide evidence that zebrafish acquire mycobacteria primarily through the intestinal tract, resulting in mycobacterial dissemination. [source] | ||||||||||||||||||||||||||||||||||