Vertical

Distribution by Scientific Domains

Kinds of Vertical

  • different vertical

  • Terms modified by Vertical

  • vertical aggradation
  • vertical alignment
  • vertical array
  • vertical augmentation
  • vertical bone augmentation
  • vertical bridgman method
  • vertical cavity surface emitting laser
  • vertical change
  • vertical component
  • vertical coordinate
  • vertical coordination
  • vertical cross-section
  • vertical cup
  • vertical deformation
  • vertical detachment energy
  • vertical differentiation
  • vertical dimension
  • vertical direction
  • vertical discretization
  • vertical disintegration
  • vertical displacement
  • vertical distance
  • vertical distribution
  • vertical excitation energy
  • vertical flow
  • vertical flux
  • vertical force
  • vertical fracture
  • vertical gaze palsy
  • vertical gradient
  • vertical growth
  • vertical height
  • vertical inheritance
  • vertical integration
  • vertical ionization energy
  • vertical limb
  • vertical line
  • vertical load
  • vertical loading
  • vertical merger
  • vertical migration
  • vertical mixing
  • vertical motion
  • vertical movement
  • vertical movement pattern
  • vertical orientation
  • vertical phase separation
  • vertical pipe
  • vertical plane
  • vertical plate
  • vertical position
  • vertical profile
  • vertical redistribution
  • vertical resolution
  • vertical restraint
  • vertical root fractures
  • vertical scale
  • vertical section
  • vertical slope
  • vertical stratification
  • vertical stress
  • vertical strip
  • vertical structure
  • vertical surface
  • vertical transmission
  • vertical vein
  • vertical velocity
  • vertical wall
  • vertical wind
  • vertical wind shear

  • Selected Abstracts


    Foreign direct investment and the dark side of decentralization

    ECONOMIC POLICY, Issue 49 2007
    Sebastian G. Kessing
    SUMMARY Fiscal decentralization VERTICAL, HORIZONTAL, AND FDI Both in the developed and developing world, decentralization of fiscal policy is frequently argued to foster investment, because allowing investors to choose between competing locations should make it difficult for each jurisdiction to tax the investment's returns. We point out that this ,horizontal' dimension of decentralization cannot eliminate ex post incentives to tax investments once they are irreversibly located in a jurisdiction, and that the negative ex ante investment effects of such ,hold up' problems are actually stronger when decentralization inevitably leads to multiple levels of taxation power in each location. Empirically, we detect significant negative effects on FDI of the ,vertical' dimension of decentralization, measured by the number of government layers, in a data set containing many countries and many suitable control variables. Indicators of overall fiscal decentralization do not appear to affect the investment climate negatively per se, but our theoretical arguments and empirical results suggest that policymakers should consider very carefully the form and degree of government decentralization if they aim at improving the investment climate. , Sebastian G. Kessing, Kai A. Konrad and Christos Kotsogiannis [source]


    HOST GROWTH CONDITIONS INFLUENCE EXPERIMENTAL EVOLUTION OF LIFE HISTORY AND VIRULENCE OF A PARASITE WITH VERTICAL AND HORIZONTAL TRANSMISSION

    EVOLUTION, Issue 7 2010
    Hélène Magalon
    In parasites with mixed modes of transmission, ecological conditions may determine the relative importance of vertical and horizontal transmission for parasite fitness. This may lead to differential selection pressure on the efficiency of the two modes of transmission and on parasite virulence. In populations with high birth rates, increased opportunities for vertical transmission may select for higher vertical transmissibility and possibly lower virulence. We tested this idea in experimental populations of the protozoan Paramecium caudatum and its bacterial parasite Holospora undulata. Serial dilution produced constant host population growth and frequent vertical transmission. Consistent with predictions, evolved parasites from this "high-growth" treatment had higher fidelity of vertical transmission and lower virulence than parasites from host populations constantly kept near their carrying capacity ("low-growth treatment"). High-growth parasites also produced fewer, but more infectious horizontal transmission stages, suggesting the compensation of trade-offs between vertical and horizontal transmission components in this treatment. These results illustrate how environmentally driven changes in host demography can promote evolutionary divergence of parasite life history and transmission strategies. [source]


    VERTICAL AND HORIZONTAL ECONOMIES IN THE ELECTRIC UTILITY INDUSTRY: AN INTEGRATED APPROACH

    ANNALS OF PUBLIC AND COOPERATIVE ECONOMICS, Issue 3 2009
    Massimiliano Piacenza
    ABSTRACT,:,The empirical literature on the cost structure of the electric utility industry traditionally focused on the measurement of specific technological properties: 1) scale economies in generation or distribution; 2) multi-product (or horizontal) scope economies at one particular stage; 3) multi-stage (or vertical) scope economies. By adopting an integrated approach, which simultaneously considers both horizontal and vertical aspects of the technology, we find the presence, on a sample of Italian electric utilities, of both vertical integration gains and horizontal scope economies at the downstream stage. In the light of recent regulatory reforms aiming at restructuring European electricity markets, our findings have important policy implications as for the proper configuration of the industry. Moreover, this methodology can be usefully applied to the study of the production structure of other public network utilities involved in similar vertical and horizontal reorganization processes. [source]


    A graphical generalized implementation of SENSE reconstruction using Matlab

    CONCEPTS IN MAGNETIC RESONANCE, Issue 3 2010
    Hammad Omer
    Abstract Parallel acquisition of Magnetic Resonance Imaging (MRI) has the potential to significantly reduce the scan time. SENSE is one of the many techniques for the reconstruction of parallel MRI images. A generalized algorithm for SENSE reconstruction and theoretical background is presented. This algorithm can be used for SENSE reconstruction for any acceleration factor between 2 and 8, for any Phase Encode direction (Horizontal or Vertical), with or without Regularization. The user can select a particular type of Regularization. A GUI based implementation of the algorithm is also given. Signal-to-noise ratio, artefact power, and g -factor map are used to quantify the quality of reconstruction. The effects of different acceleration factors on these parameters are also discussed. The GUI based implementation of SENSE reconstruction provides an easy selection of various parameters needed for reconstruction of parallel MRI images and helps in an efficient reconstruction and analysis of the quality of reconstruction. © 2010 Wiley Periodicals, Inc. Concepts Magn Reson Part A 36A: 178,186, 2010. [source]


    Rigidity of commonly used dental trauma splints

    DENTAL TRAUMATOLOGY, Issue 3 2009
    Christine Berthold
    We evaluated the rigidity of various commonly used splints in vitro Material and Methods:, An acrylic resin model was used. The central incisors simulated injured teeth, with increased vertical and horizontal mobility. The lateral incisors and canines stimulated uninjured teeth. Tooth mobility was measured with the Periotest® device. Vertical and horizontal measurements were made before and after splinting, and the difference between values was defined as the splint effect. We evaluated 4 composite splints, 3 wire-composite splints, a titanium trauma splint, a titanium ring splint, a bracket splint, and 2 Schuchardt splints Results:, For all injured teeth and all splints, there was a significant splint effect for the vertical and horizontal dimensions (P < 0.05). For injured teeth, the composite splints produced the largest changes in vertical tooth mobility; wire-composite splints 1 and 2, using orthodontic wires, produced the smallest vertical splint effects. For uninjured teeth, the Schuchardt 1 splint and the bracket splint produced the largest splint effects; wire-composite splints 1 and 2 produced only a slight change in tooth mobility. Composite splints 2 and 3 produced the largest horizontal splint effects for injured teeth, and the 4 composite splints produced the largest horizontal splint effects for uninjured teeth. The most horizontally flexible splints were the titanium trauma splint and wire-composite splints 1 and 2. Conclusions:, According to the current guidelines and within the limits of an in vitro study, it can be stated that flexible or semirigid splints such as the titanium trauma splint and wire-composite splints 1 and 2 are appropriate for splinting teeth with dislocation injuries and root fractures, whereas rigid splints such as wire-composite splint 3 and the titanium ring splint can be used to treat alveolar process fractures. [source]


    Protein deficiency balance as a predictor of clinical outcome in hereditary spherocytosis

    EUROPEAN JOURNAL OF HAEMATOLOGY, Issue 5 2005
    S. Rocha
    Abstract:, Vertical and horizontal interactions between membrane constituents account for integrity, strength and deformability of the erythrocyte. Disruption of vertical interactions caused by membrane protein deficiencies in hereditary spherocytosis (HS), favor membrane vesiculation with development of spherocytic cells. Our aim was to evaluate the hematological and clinical presentation of HS according to the type and amount of protein deficiency. We studied 81 Portuguese individuals, 71 belonging to 21 families plus 10 unrelated subjects, and found that 51 of them were HS patients. Patients were classified as presenting mild, typical or severe HS, according to laboratory results and clinical follow-up. We performed screening tests and the standardized electrophoretic membrane protein analysis to identify and quantify protein deficiencies. We found band 3 and ankyrin deficiencies as the major causes for HS. The ratios between the value of the primary and/or secondary protein deficiencies showed significantly different values according to the severity of HS, and a significant inverse correlation with the severity of HS was observed. In mild HS, the ratios between protein deficiencies reflected equivalent protein deficiencies, while an unbalance was observed in typical HS, which was enhanced in severe HS. Our data suggest that the relative quantification of each major membrane protein and of the ratios between the values of protein deficiencies may be helpful in providing additional data about the clinical outcome of HS. [source]


    Determination of moisture content in a deformable soil using time-domain reflectometry (TDR)

    EUROPEAN JOURNAL OF SOIL SCIENCE, Issue 1 2000
    D. J. Kim
    Summary Time-domain reflectometry (TDR) is being used increasingly for measuring the moisture content of porous media. However, successful application for measuring water in soil has been limited to non-deformable soils, and it would be a valuable extension of the technique if it could be used for soils that shrink on drying. We have recently investigated its application to soils rich in clay and organic matter and peats. Here we propose a method for determining moisture content in deformable soils based on the relation between the dielectric constant, K, and the volumetric moisture content, ,, measured by TDR. Parallel TDR probes with a length of 15 cm and a spacing of 2 cm were placed horizontally in soil cores with a diameter of 20 cm and height of 10 cm taken from a forest. The soil is very porous with large proportions of both silt and clay. The sample weight and travel time of the electromagnetic wave guided by parallel TDR probes were simultaneously measured as a function of time, from saturation to oven-dryness during which the core samples shrank considerably. Vertical and horizontal components of shrinkage were also measured to take the air-exposed region of TDR probe into account in the determination of K. The effect of deformation on volumetric moisture content was formulated for two different expressions, namely actual volumetric moisture content (AVMC) and fictitious (uncorrected) volumetric moisture content (FVMC). The effects of air-exposure and expressions of volumetric moisture content on the relation between K and, were examined by fitting the observations with a third-order polynomial. Neglecting the travel time in the air-exposed part or use of the FVMC underestimated the , for a given K. The difference was more pronounced between AVMC and FVMC than between two different dielectric constants, i.e. accounting for air-exposure, Kac, and not accounting for air-exposure, Kau. When the existing empirical models were compared with the fitted results, most underestimated the relation based on the AVMC. This indicates that published empirical models do not reflect the effect of deformation on the determination of , in our forest soil. Correct use of the , expression has more impact on determining moisture content of a deformable soil than the accommodation of travel time through the air-exposed region of TDR probe. [source]


    Vertical Nanostructures: Vertical (La,Sr)MnO3 Nanorods from Track-Etched Polymers Directly Buffering Substrates (Adv. Funct.

    ADVANCED FUNCTIONAL MATERIALS, Issue 6 2010
    Mater.
    The inside cover image shows a tilted SEMFE image of La0.7Sr0.3MnO3 vertical nanorods. A. Carretero-Genevrier and co-workers have established a new method to generate vertical complex oxides nanostructures based on a sol,gel precursor solution and using track-etched polymers that act to buffer the substrate, which is described on page 892. These vertical nanorods grown at mild temperature undergo a complete structural, morphological, and chemical transformation into single crystalline (LaSr)xOy nanopyramids upon thermal activation at 1000°C. [source]


    Vertical (La,Sr)MnO3 Nanorods from Track-Etched Polymers Directly Buffering Substrates

    ADVANCED FUNCTIONAL MATERIALS, Issue 6 2010
    Adrián Carretero-Genevrier
    Abstract A novel and general methodology for preparing vertical, complex-oxide nanostructures from a sol,gel-based polymer-precursor solutions is developed using track-etched polymers directly buffering substrates. This method is able to develop a nanostructure over the entire substrate, the dimensions and localization of the vertical nanostructures being preset by the polymeric nanotemplate. Thereby, nanostructures with lateral sizes in the range of 100 to 300,nm and up to 500,nm in height have been grown. Two examples are presented herein, the latter being the evolution of the initial, metastable nanostructure. Specifically, La0.7Sr0.3MnO3 polycrystalline rods are grown at mild temperatures (800,°C); upon strong thermal activation (1000,°C) they suffer a profound transformation into vertical, single-crystalline (La,Sr)xOy nanopyramids sitting on a La0.7Sr0.3MnO3 epitaxial wetting layer. The driving force for this outstanding nanostructural evolution is the minimization of the total energy of the system, which is reached by reducing the grain-boundary, total-surface, and strain-relaxation energies. Finally, advanced electron-microscopy techniques are used to highlight the complex phase separation and structural transformations occurring when the metastable state is overcome. [source]


    Vertical or holistic decentralization of the health sector?

    INTERNATIONAL JOURNAL OF HEALTH PLANNING AND MANAGEMENT, Issue 4 2000
    Experiences from Zambia, Uganda
    Abstract Many countries in Africa have embarked on health sector reforms. The design of the reforms differs considerably. A key feature of the reforms is decentralization, of which Uganda and Zambia are implementing two different models. This paper analyses the two models of health sector reform, and their implications for ultimate development goals. In Uganda, the whole government has been decentralized, with a wide range of powers and resources transferred to the districts. The health care system is part of the political set up of the country. In Zambia, only the health sector has been decentralized. Power and resources for health care have been divested to new parallel organizations. While useful lessons can be drawn from the managerial and administrative experience in the two countries, not least concerning donor coordination, it seems that neither form of decentralization has so far led to a clear and appreciable improvement of health services and, ultimately, to a clear focus on development goals, such as poverty alleviation. The conditions for this to happen are discussed in this paper. Copyright © 2000 John Wiley & Sons, Ltd. [source]


    Yield, Boll Distribution and Fibre Quality of Hybrid Cotton (Gossypium hirsutum L.) as influenced by Organic and Modern Methods of Cultivation

    JOURNAL OF AGRONOMY AND CROP SCIENCE, Issue 4 2006
    D. Blaise
    Abstract India is the largest cotton-growing country (8.9 million hectares) in the world and most of the area is rain-dependent. Large amount of pesticides are used for the control of sucking pests and lepidopterans. Increasing demand for clean organic fibre has led to an interest in organic cotton. However, information on the effects of organic cultivation on fibre quality is limited. Seed cotton yield and fibre quality (length, strength, micronaire and uniformity) were determined for an organic and modern method of cultivation during 3 years (2002,2003 to 2004,2005) of a 11-year (1994,1995 to 2004,2005) study. Vertical and horizontal distribution of bolls on a cotton plant was also determined in 2003,2004 and 2004,2005. At the end of year 11, soil samples were collected and analysed for soil organic carbon content, water-stable aggregates (%), and mean weight diameter. Averaged over 3 years, an additional 94 kg seed cotton ha,1 was produced in the organic over the modern method of cultivation and the difference was significant. The year × treatment interaction was significant. Seed cotton yield in the organic plots was significantly greater than the modern method of cultivation plots in 2003,2004 because of a well-distributed normal rainfall and low pest incidence. The main stem nodes 13,22 accounted for the largest numbers of bolls present on the plant. Plants of the organic plots had significantly (37,71 %) more bolls on nodes 13,27 than those for the plants of the modern method of cultivation. Lateral distribution of bolls on a sympodial (fruiting) branch, was noticed up to fruiting point 11. However, treatment differences were not significant. With regard to fibre quality (length, strength, fineness and uniformity), differences between years were significant. Inferior quality fibre was produced in 2004,2005 because of delayed planting and early cessation of rain. On average, cotton grown under organic conditions compared with the modern method of cultivation had significantly better fibre length (25.1 vs. 24.0 mm) and strength (18.8 vs. 17.9 g tex,1). Soil samples of the organic plots had significantly greater C content, water-stable aggregates and mean weight diameter than the modern method of cultivation plots. Differences were restricted to the top layers (0,0.1 and 0.1,0.2 m). Yield benefits of growing cotton in an organic system over the modern method of cultivation are expected to be greater in years receiving normal rainfall and having low pest incidence. [source]


    In vitro differences of stress concentrations for internal and external hex implant,abutment connections: a short communication

    JOURNAL OF ORAL REHABILITATION, Issue 1 2006
    Y. MAEDA
    summary, The aim of this study was to clarify the difference in the stress distribution patterns between implants with external-hex or internal-hex connection systems using in vitro models. Three 13 mm fixtures with external-hex and internal-hex connections were installed into an acrylic bone analogue. One piece abutments of 7 mm height was connected. Strain gauges were attached to the abutment surface, and the cervical and fixture tip areas of the bone analogue surface. Vertical and horizontal load applied was 30 N. Data were normalized for each model by obtaining values relative to the sum of the three values. Almost the same force distribution pattern was found under vertical load in both systems. Fixtures with external-hex showed an increase in strain at the cervical area under horizontal load, while in internal-hex fixtures the strain was at the fixture tip area. Within limitations of our model study, it was suggested that fixtures with internal-hex showed widely spread force distribution down to the fixture tip compared with external hex ones. [source]


    Effect of Compromised Cortical Bone on Implant Load Distribution

    JOURNAL OF PROSTHODONTICS, Issue 8 2008
    vanç Akça DDS
    Abstract Purpose: To investigate photoelastically the difference in load distribution of dental implants with different implant neck designs in intact and compromised bone. Materials and Methods: Composite photoelastic models were fabricated using two different resins to simulate trabecular bone and a 1-mm thick layer of cortical bone. The following parallel-sided, threaded implants were centrally located in individual models representing intact and compromised cortical bone: Straumann (4.1-mm diameter × 12-mm length), AstraTech (4.0-mm diameter × 13-mm length), and 3i (3.75-mm diameter × 13-mm length). The compromised cortical bone condition was simulated by contaminating a 1-mm neck portion with Vaseline to impair the implant,resin interface. Vertical and oblique static loads were applied on the abutments, and the resulting stresses were monitored photoelastically and recorded photograhphically. Results: For the fully intact condition, the highest stresses were observed around the crest and apical region for all implant designs under vertical and inclined loads. There were no appreciable differences in magnitude or distribution between implant types. With compromised cortical bone, for all designs and load directions, higher stresses in the supporting structures were observed. Increased stresses were noted especially at the cortical bone,trabecular bone interface. Somewhat lower stress levels were observed with the 3i implant. Conclusions: The condition of implant,cortical bone contact has considerable influence on stress distribution. A compromised cortical bone condition caused higher level stresses for all implant designs tested. [source]


    Trade and Labour Markets: Vertical and Regional Differentiation in Italy

    LABOUR, Issue 3 2000
    Giuseppe Celi
    The labour market misfortunes of the less skilled and rapid growth of international trade in manufactured goods with less advanced countries are linked by the paradoxical observation that trade theorists are in the forefront of those denying the importance of trade in income distribution. This paper analyses this conclusion by stressing the importance of vertical differentiation of trade flows and regional differentiation of skills in order to identify labour market effects of trade integration. Vertical and regional differentiation in trade and labour markets are analysed for a country, Italy, where these two elements seem to play a crucial role. The results show a likely displacement effect on unskilled labour due to trade flows with less advanced countries. Given the characteristics of Italian trade and labour markets, a stronger trade-induced displacement effect on demand for unskilled labour takes place in the North of the country. Thus the vertical differentiation in Italian intra-industry trade is a warning against understating the effect of trade on labour markets if product heterogeneity is not adequately considered. The regional differentiation of skill intensity is another warning against understating the effect of trade on labour markets whenever cross-sectoral effects and the change in relative specialization are not adequately considered. [source]


    Design of forming shoulders with complex cross-sections

    PACKAGING TECHNOLOGY AND SCIENCE, Issue 4 2005
    C. J. McPherson
    Abstract Vertical ,form, fill and seal' machines are used to produce bags for packing particulate or multiple objects. In operation, film is drawn over a forming shoulder and the good design of the surfaces of the shoulder is vital to the successful operation. This paper reviews underlying geometrical definition for the shoulder, corresponding to a filling tube with circular cross-section. In practice, such cross-sections occur frequently, but other variant shapes are becoming increasingly common. A method is discussed and demonstrated for extending the approach to allow tubes formed from circular arcs and straight line segments to be handled. Copyright © 2005 John Wiley & Sons, Ltd. [source]


    Undermining State Capacity: Vertical and Horizontal Diffusions of Fiscal Power in China

    ASIAN POLITICS AND POLICY, Issue 3 2009
    Jing Vivian Zhan
    Since the late 1970s, China's fiscal system has facilitated the initiation and implementation of economic reforms and greatly contributed to China's remarkable economic achievements. However, weaknesses of the fiscal system have been exposed that have aroused concerns about the weakening of state capacity. While many have discussed the loss of central fiscal control over localities under decentralization and its negative consequences, not enough attention has been paid to another major problem: the diffusion of fiscal power to nonfiscal government departments. In this article, I argue that the existence of the extra-budgetary system has granted ad hoc taxation power to nonfiscal departments and led to the mismanagement of fiscal revenue. Compared with the vertical diffusion of fiscal power, i.e., the devolution of fiscal authority from central to lower-level governments, the horizontal diffusion of fiscal power is more difficult to control and more detrimental to the institutionalization of China's fiscal system. [source]


    Holdup and Pressure Drop in Vertical and Near-Vertical Three-Phase Up-Flow: A Collection of Flow Regimes

    ASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 1-2 2002
    P.L. Spedding
    Three-phase oil, water and air data are reported for vertical and near vertical +86 5° upflow in a 0 026 m i d pipe In general, the liquid holdup for near vertical flow was greater than for the corresponding vertical upflow, the exception being at low liquid and superficial velocities under 0 6 m/s and high superficial gas velocities over 20 m/s Here the liquid holdup varied being sometimes below and other times above the corresponding vertical value These variations of liquid holdup were shown to depend on the fine structure of the flow patterns present The total pressure drop and its component parts showed significantly different patterns of behaviour depending on whether the superficial gas velocity was above or below the rise velocity of a Taylor bubble The total pressure drop generally was greater for near vertical flow compared to the vertical upflow case but reflected changes in the fine structure of the flow patterns A comprehensive collection of flow regimes is included in this paper [source]


    Policy Formulation in Australian Government: Vertical and Horizontal Axes

    AUSTRALIAN JOURNAL OF PUBLIC ADMINISTRATION, Issue 2 2000
    Craig Matheson
    Studies of the policy process in Australia have focused on particular institutions or decisions rather than on its overarching properties. One such property is the vertical and horizontal ,axes' of policy-making. The former comprises hierarchical relationships whereas the latter comprise relationships of bargaining, negotiation and persuasion. Vertical axes enable governments to take and enforce technically rational decisions in pursuit of consistent goals whereas horizontal axes permit governments to make broadly-based decisions that have group assent and electoral support. Vertical axes have strengthened in recent years and have brought increased technical rationality and consistency. This has come at a cost of limiting of the scope of political debate and a loss of electoral support for government though. [source]


    Force transmission of one- and two-piece morse-taper oral implants: a nonlinear finite element analysis

    CLINICAL ORAL IMPLANTS RESEARCH, Issue 4 2004
    Murat Cavit Çehreli
    Abstract Purpose: To compare force transmission behaviors of one-piece (1-P) and two-piece (2-P) morse-taper oral implants. Material and methods: A three-dimensional finite element model of a morse-taper oral implant and a solid abutment was constructed separately. The implant,abutment complex was embedded in a Ø 1.5 cm × 1.5 cm acrylic resin cylinder. Vertical and oblique forces of 50 N and 100 N were applied on the abutment and solved by two different analyses. First, contact analysis was performed in the implant,abutment complex to evaluate a 2-P implant. Then, the components were bonded with a separation force of 1020 N to analyze a 1-P implant. Results: Von Mises stresses in the implant, principal stresses, and displacements in the resin were the same for both designs under vertical loading. Under oblique loading, principal stresses and displacement values in the resin were the same, but the magnitudes of Von Mises stresses were higher in the 2-P implant. The principal stress distributions around both implants in the acrylic bone were similar under both loading conditions. Conclusion: 2-P implants experience higher mechanical stress under oblique loading. Nevertheless, the 1-P- or 2-P morse-taper nature of an implant is not a decisive factor for the magnitude and distribution of stresses, and displacements in supporting tissues. Résumé Le but de cette étude a été de comparer les comportements de la transmission de la force desimplants buccaux en deux pièces. Un modèle d'éléments finis tridimensionnels d'un implant buccal et d'un pilier solide ont été construits séparément. Le complexe implant/pilier a été enfoui dans un cylindre de résine acrylique d'un diamètre 1,5 × 1,5 cm. Des forces obliques et verticales de 50 et 100 N ont été appliquées sur les piliers et analysées par deux méthodes. D'abord, l'analyse de contraste a été effectuée dans le complexe implant/pilier pour évaluer un implant en deux pièces. Ensuite, les composants ont été reliés avec une force de séparation de 1020N pour analyser un implant en une pièce. Les stress de Von Mises dans l'implant, les principaux stress et les déplacements dans la résine étaient les mêmes pour les deux modèles sous charge verticale. Lorsqu'une charge oblique était appliquée, les stress principaux et les valeurs de déplacements dans la résine étaient semblables mais l'amplitude des stress de Von Mises était plus importante dans l'implant à deux pièces. Les distributions des stress principaux autour des deux implants dans l'os acrylique était semblable sous les deux conditions de charge. Les implants en deux pièces subissent un stress mécanique plus important sous une charge oblique. Cependant, l'implant en une ou deux pièces avec un cône morse n'est pas un facteur décisif sur l'amplitude et la distribution des stress, et les déplacements des tissus de support. Zusammenfassung Ziel: Die Kraftübertragungsverhältnisse von ein- und zweiteiligen oralen Implantaten mit konischem Sitz der Sekundärteile zu untersuchen. Material und Methode: Es wurde je ein separates dreidimensionales Finite Element Modell eines oralen Implantats mit konischem Sitz der Sekundärteile und ein Massivsekundärteil konstruiert. Der Implantat-Sekundärteilkomplex wurde in einem Zylinder aus Acryl mit Durchmesser 1.5cm und Länge 1.5cm eingebettet. Vertikale und schräge Kräfte von 50 N und 100 N wurden auf das Sekundärteil appliziert und durch zwei verschiedene Analysen ausgewertet. Zuerst wurde eine Kontaktanalyse im Implantat-Sekundärteilkomplex zur Auswertung eines zweiteiligen Implantats durchgeführt. Dann wurden die Komponenten mit einer Separationskraft von 1020 N verbunden, um ein einteiliges Implantat zu analysieren. Resultate: Unter vertikaler Belastung waren der Van Mises Stress im Implantat, der generelle Stress und die Displatzierung im Kunststoff für beide Konstruktionen gleich. Unter schräger Belastung waren der generelle Stress und die Displatzierungswerte im Kunststoff die gleichen, jedoch war das Ausmass des von Mises Stress im zweiteiligen Implantat grösser. Die generelle Stressverteilung im Akrylknochen um die Implantate war unter beiden Belastungsbedingungen ähnlich. Schlussfolgerung: Zweiteilige Implantate erleiden grösseren mechanischen Stress unter schräger Belastung. Jedoch ist die ein- oder zweiteilige Konstruktion mit konischem Sitz der Sekundärteile bei Implantaten kein entscheidender Faktor für das Ausmass und die Verteilung des Stresses und für die Displatzierung in den Verankerungsgeweben. Resumen Intención: Comparar los comportamientos de transmisión de fuerzas de implantes orales en cono morse de una o dos piezas. Material y métodos: Se construyeron separadamente un modelo tridimensional de elemento finito de un implante oral de cono morse y un pilar sólido. El complejo implante-pilar se embebió en un cilindro de resina acrílica de , 1.5 cm × 1.5 cm. Se aplicaron fuerzas oblicuas de 50 N y 100 N sobre el pilar y se resolvieron por medio de dos análisis diferentes. Primero, se llevó a cabo un análisis de contacto en el complejo implante-pilar para evaluar un implante de dos piezas. Después, se unieron los componentes con una fuerza de separación de 1020 N para analizar un implante de una sola pieza. Resultados: El estrés de Von Mises, el estrés principal, y el desplazamiento en la resina fueron los mismos para ambos diseños bajo carga vertical. Bajo carga oblicua, los valores de estrés principal y desplazamiento en resina fueron los mismos, pero la magnitud de los estreses de Von Mises fueron mayores en los implantes de dos piezas. Las distribuciones del estrés principal alrededor de ambos implantes in el hueso acrílico fueron similares bajo ambas condiciones de carga. Conclusión: Los implantes de dos piezas experimentan un estrés mecánico mas alto bajo carga oblicua. Sin embargo, la naturaleza de un implante de cono morse de una o dos piezas no es un factor decisivo en la magnitud y distribución de los estreses, y desplazamientos en los tejidos de soporte. [source]


    A cache-efficient implementation of the lattice Boltzmann method for the two-dimensional diffusion equation

    CONCURRENCY AND COMPUTATION: PRACTICE & EXPERIENCE, Issue 14 2004
    A. C. Velivelli
    Abstract The lattice Boltzmann method is an important technique for the numerical solution of partial differential equations because it has nearly ideal scalability on parallel computers for many applications. However, to achieve the scalability and speed potential of the lattice Boltzmann technique, the issues of data reusability in cache-based computer architectures must be addressed. Utilizing the two-dimensional diffusion equation, , this paper examines cache optimization for the lattice Boltzmann method in both serial and parallel implementations. In this study, speedups due to cache optimization were found to be 1.9,2.5 for the serial implementation and 3.6,3.8 for the parallel case in which the domain decomposition was optimized for stride-one access. In the parallel non-cached implementation, the method of domain decomposition (horizontal or vertical) used for parallelization did not significantly affect the compute time. In contrast, the cache-based implementation of the lattice Boltzmann method was significantly faster when the domain decomposition was optimized for stride-one access. Additionally, the cache-optimized lattice Boltzmann method in which the domain decomposition was optimized for stride-one access displayed superlinear scalability on all problem sizes as the number of processors was increased. Copyright © 2004 John Wiley & Sons, Ltd. [source]


    Shade-Coffee Plantations as Refuges for Tropical Wild Orchids in Central Veracruz, Mexico

    CONSERVATION BIOLOGY, Issue 3 2005
    LISLIE SOLIS-MONTERO
    biología reproductiva; epifitas vasculares; estratificación vertical; estructura poblacional; limitación de polinizador Abstract:,In central Veracruz, Mexico, coffee plantations have replaced large areas of lower montane cloud forest. Shade-coffee plantations with high levels of structural diversity provide refuge for forest-dependent biota (e.g., birds and insects). Orchids typical of natural forest may also be found in the canopy of shade-coffee agroecosystems. It is not known, however, whether these are relicts from the original forest vegetation or if the plantations themselves provide the necessary conditions to support a self-sustained orchid population. We studied the population structure of the epiphytic orchids Jacquiniella teretifolia (Sw.) Britton & Willson, Scaphyglottis livida (Lindl.) Schltr., and Maxillaria densa Lindl. in a shade-coffee plantation (commercial polyculture) in central Veracruz. We also studied the previously undescribed reproductive biology of the latter two species. Our results show that the three orchid species had high population densities (>800 plants/ha). In our study site, 50% to 68% of the orchid plants of the target species were young individuals (less than five shoots). Reproductive structures were present in 80% of individuals larger than 30 shoots in the three species. M. densa is self-incompatible, and the fruit set obtained from cross pollination (42.7%) was higher than that obtained from natural pollination (18.2%), suggesting that this species could be pollinator limited. S. livida is autocompatible, not autogamous, and was not pollinator limited. Our results show that the coffee plantation had abundant orchid populations with log-normal size/age structures. Two of the target species, M. densa and S. livida, depend on pollinators to reproduce. It is clear that pollinators that allow orchids to set a high proportion of fruits persist in shade-coffee plantations. Coffee plantations may not replace the original conditions of a forest, but it is possible that these and other orchid species survive and reproduce in coffee plantations that provide appropriate microclimate conditions for the plants, including pollinators. Resumen:,En el centro de Veracruz, México, las plantaciones de café han reemplazado a extensas áreas de bosque nublado montano. Las plantaciones cafetaleras de sombra con altos niveles de diversidad estructural proporcionan refugio a biota dependiente de bosques (e. g., aves e insectos). En el dosel de agroecosistemas de café de sombra también se pueden encontrar orquídeas típicas de bosques naturales. Sin embargo, no se conoce si son relictos de la vegetación del bosque original o si las plantaciones mismas proporcionan los recursos necesarios para soportar a una población de orquídeas auto sostenida. Estudiamos la estructura de la población de orquídeas epifitas Jacquiniella teretifolia (Sw.) Britton & Willson, Scaphyglottis livida (Lindl.) Schltr y Maxillaria densa Lindl en una plantación de café de sombra (policultivo comercial) en el centro de Veracruz. También estudiamos la biología reproductiva, no descrita previamente, de las últimas dos especies. Nuestros resultados muestran que las tres especies de orquídea tuvieron densidades poblacionales altas (>800 plantas/ha). En nuestro sitio de estudio, entre 50% y 68% de las plantas de las especies estudiadas eran individuos jóvenes (menos de cinco rebrotes). En las tres especies hubo presencia de estructuras reproductivas en 80% de los individuos con más de 30 rebrotes. M. densa es auto incompatible, y el conjunto de frutos obtenido por polinización cruzada (42.7%) fue mayor que el obtenido por polinización natural (18.2%), lo que sugiere que esta especie puede estar limitada por polinizadores. S. livida es autocompatible no autogama, y no fue limitada por polinizadores. Nuestros resultados muestran que la plantación de café tenía poblaciones de orquídeas abundantes con estructuras tamaño/edad log normales. Dos de las especies, M. densa y S. livida, dependen de polinizadores para su reproducción. Es claro que los polinizadores que permiten una alta proporción de frutos a las orquídeas persisten en las plantaciones. Puede que las plantaciones de café no sustituyan las condiciones originales de un bosque, pero es posible que estas, y otras, especies de orquídeas sobrevivan y se reproduzcan en plantaciones de café que proporcionen condiciones microclimáticas adecuadas, incluyendo polinizadores, para las plantas. [source]


    An evaluation of the Periotest® method as a tool for monitoring tooth mobility in dental traumatology

    DENTAL TRAUMATOLOGY, Issue 2 2010
    Christine Berthold
    The aims of this study were to determine normal Periotest® values in the vertical and horizontal dimensions of periodontally healthy teeth in individuals aged 20,35 years and investigate the reliability of Periotest® in terms of intra-series and inter-series reproducibility before and after applying a dental trauma splint in vivo. Materials and methods:, Periotest® values were measured in periodontally healthy dental students (n = 33; mean age 24.7 years) at reproducible measuring points in the vertical and horizontal dimensions, before and after splint insertion. Three readings were taken per series to observe the intra-series reproducibility; three series were measured to test inter-series reproducibility (Friedman-test; P , 0.001). Two different wire-composite splints, 0.45 mm Dentaflex and 0.8 × 1.8 Strengtheners, were inserted and the Periotest® values were measured. Results:, The median Periotest® values before splinting were: canines -2.5, lateral incisors -0.9, and central incisors 0.0 for the vertical dimension, and canines 1.1, lateral incisors 3.2, and central incisors 3.6 for the horizontal dimension. The intra-series and inter-series Periotest® values were highly reproducible. Conclusion:, The Periotest® method provides highly reproducible results. Focused on dental trauma, the method can be applied diagnostically during the splint and follow-up period and for evaluating splint rigidity. [source]


    Rigidity of commonly used dental trauma splints

    DENTAL TRAUMATOLOGY, Issue 3 2009
    Christine Berthold
    We evaluated the rigidity of various commonly used splints in vitro Material and Methods:, An acrylic resin model was used. The central incisors simulated injured teeth, with increased vertical and horizontal mobility. The lateral incisors and canines stimulated uninjured teeth. Tooth mobility was measured with the Periotest® device. Vertical and horizontal measurements were made before and after splinting, and the difference between values was defined as the splint effect. We evaluated 4 composite splints, 3 wire-composite splints, a titanium trauma splint, a titanium ring splint, a bracket splint, and 2 Schuchardt splints Results:, For all injured teeth and all splints, there was a significant splint effect for the vertical and horizontal dimensions (P < 0.05). For injured teeth, the composite splints produced the largest changes in vertical tooth mobility; wire-composite splints 1 and 2, using orthodontic wires, produced the smallest vertical splint effects. For uninjured teeth, the Schuchardt 1 splint and the bracket splint produced the largest splint effects; wire-composite splints 1 and 2 produced only a slight change in tooth mobility. Composite splints 2 and 3 produced the largest horizontal splint effects for injured teeth, and the 4 composite splints produced the largest horizontal splint effects for uninjured teeth. The most horizontally flexible splints were the titanium trauma splint and wire-composite splints 1 and 2. Conclusions:, According to the current guidelines and within the limits of an in vitro study, it can be stated that flexible or semirigid splints such as the titanium trauma splint and wire-composite splints 1 and 2 are appropriate for splinting teeth with dislocation injuries and root fractures, whereas rigid splints such as wire-composite splint 3 and the titanium ring splint can be used to treat alveolar process fractures. [source]


    The histopathology of alopecia areata in vertical and horizontal sections

    DERMATOLOGIC THERAPY, Issue 4 2001
    David A. Whiting
    Alopecia areata (AA) is a relatively common disease affecting 1.7% of Americans by the age of 50 years. The diagnosis is usually made on clinical grounds. In some cases the diagnosis is elusive and biopsies are necessary. In other cases biopsies are useful from a prognostic point of view to determine whether there are enough follicles left for possible future regrowth. In view of the active research being conducted into AA, biopsies provide valuable material for further investigation. The diagnosis of AA is improved by the use of horizontal sections in addition to or instead of vertical sections of scalp biopsies. The histopathologic features favoring the diagnosis of AA include peribulbar and intrabulbar mononuclear infiltrates, degenerative changes in the hair matrix, decreased numbers of terminal anagen follicles, increased numbers of terminal catagen and telogen follicles, an increased number of follicular stelae, an increased number of miniaturized vellus hair follicles, and pigment incontinence of hair bulbs and follicular stelae. Follicular counts with horizontal sections are particularly helpful in making the diagnosis of AA when the biopsy has been taken between acute episodes and the characteristic peribulbar inflammatory infiltrate is absent. [source]


    Influence of parental deprivation on the behavioral development in Octodon degus: Modulation by maternal vocalizations

    DEVELOPMENTAL PSYCHOBIOLOGY, Issue 3 2003
    Katharina Braun
    Abstract Repeated separation from the family during very early stages of life is a stressful emotional experience which induces a variety of neuronal and synaptic changes in limbic cortical areas that may be related to behavioral alterations. First, we investigated whether repeated parental separation and handling, without separation from the family, leads to altered spontaneous exploratory behavior in a novel environment (open field test) in 8-day-old Octodon degus. Second, we tested whether the parentally deprived and handled animals display different stimulus-evoked exploratory behaviors in a modified open field version, in which a positive emotional stimulus, the maternal call, was presented. In the open field test a significant influence of previous emotional experience was found for the parameters of running, rearing, and vocalization. Parentally deprived degus displayed increased horizontal (running) and vertical (rearing) motoric activities, but decreased vocalization, compared to normal and handled controls. The presentation of maternal vocalizations significantly modified running, vocalization, and grooming activities, which in the case of running activity was dependent on previous emotional experience. Both deprivation-induced locomotor hyperactivity together with the reduced behavioral response towards a familiar acoustic emotional signal are similar to behavioral disturbances observed in human attachment disorders. © 2003 Wiley Periodicals, Inc. Dev Psychobiol 42: 237,245, 2003. [source]


    Post-European settlement response gradients of river sensitivity and recovery across the upper Hunter catchment, Australia

    EARTH SURFACE PROCESSES AND LANDFORMS, Issue 7 2009
    Kirstie Fryirs
    Abstract Most analyses of river adjustment have focused on parts of catchments where metamorphosis has occurred. This provides a non-representative view of river responses to human-disturbance. Although many rivers have been subjected to systematic land-use change and disturbance, significant variability is evident in the form, extent and consequences of adjustment. This study documents the catchment-wide distribution of river sensitivity and adjustment in the upper Hunter catchment, New South Wales, Australia in the period since European settlement. The spatial distribution and timing of lateral, vertical and wholesale river adjustments are used to assess river sensitivity to change. The type and pattern of rivers, influenced largely by valley setting, have induced a fragmented pattern of river adjustment in the upper Hunter catchment. Adjustments have been largely non-uniform and localized, reflecting the predominance of bedrock-controlled rivers which have limited capacity to adjust and are resilient to change. Less than 20% of river courses have experienced metamorphosis. Phases of reach-scale geomorphic adjustment to human disturbance are characterized as a gradient of primary, secondary and tertiary responses. In general terms, primary responses such as cutoffs or straightening were followed by secondary responses such as channel expansion. These secondary responses occurred between 50,70 years after initial disturbance. A subsequent tertiary phase of river recovery, denoted as a transition from predominantly erosional to predominantly depositional geomorphic processes such as channel contraction, occurred around 70,120 years after initial disturbance. Such responses are ongoing across much of the upper Hunter catchment. Copyright © 2009 John Wiley & Sons, Ltd. [source]


    The use of GIS-based digital morphometric techniques in the study of cockpit karst

    EARTH SURFACE PROCESSES AND LANDFORMS, Issue 2 2007
    P. Lyew-Ayee
    Abstract Cockpit karst landscapes are among the most distinctive landscapes in the world, and have been the focus of long-standing scientific interest. Early researchers used largely descriptive techniques to categorize the terrain, and subsequent work has not attempted to critically re-evaluate descriptions of landscapes using more sophisticated methods. The distinctive surface topography of cockpit karst areas can be characterized in order to compare them with other karst as well as non-karst areas, and to determine geological and/or climatic conditions that are responsible for the observed terrain. Process models of the rate of karst denudation or evolution can only be accurate if the contemporary morphology of the landscape is quantitatively and unambiguously defined. A detailed analysis of cockpit karst terrain is carried out using the latest GIS-based digital morphometric techniques in order to assess the nature of such terrain and provide further information for subsequent modelling, as well as other non-geomorphological applications, such as environmental management and conservation issues. The paper presents the methodology used for the digital analysis of terrain and landforms in the distinctive Cockpit Country area of Jamaica and its environs. The results indicate that cockpit karst may be categorized based on its vertical, horizontal and shape characteristics, as well as by looking at the semivariogram, slope characteristics, and landscape relief scale, which combine measures of vertical and horizontal scales. Copyright © 2006 John Wiley & Sons, Ltd. [source]


    Dynamic stiffness of deep foundations with inclined piles

    EARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 12 2010
    L. A. Padrón
    Abstract The influence of inclined piles on the dynamic response of deep foundations and superstructures is still not well understood and needs further research. For this reason, impedance functions of deep foundations with inclined piles, obtained numerically from a boundary element,finite element coupling model, are provided in this paper. More precisely, vertical, horizontal, rocking and horizontal,rocking crossed dynamic stiffness and damping functions of single inclined piles and 2 × 2 and 3 × 3 pile groups with battered elements are presented in a set of plots. The soil is assumed to be a homogeneous viscoelastic isotropic half-space and the piles are modeled as elastic compressible Euler,Bernoulli beams. The results for different pile group configurations, pile,soil stiffness ratios and rake angles are presented. Copyright © 2010 John Wiley & Sons, Ltd. [source]


    Shaking table model test on Shanghai World Financial Center Tower

    EARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 4 2007
    Xilin Lu
    Abstract The height of 101-storey Shanghai World Financial Center Tower is 492m above ground making it possible the tallest building in the world when completed. Three parallel structural systems including mega-frame structure, reinforced concrete and braced steel services core and outrigger trusses, are combined to resist vertical and lateral loads. The building could be classified as a vertically irregular structure due to a number of stiffened and transfer stories in the building. Complexities related to structural system layout are mainly exhibited in the design of services core, mega-diagonals and outrigger trusses. According to Chinese Code, the height 190 m of the building clearly exceeds the stipulated maximum height of for a composite frame/reinforced concrete core building. The aspect ratio of height to width also exceeds the stipulated limit of 7 for seismic design intensity 7. A 1/50 scaled model is made and tested on shaking table under a series of one and two-dimensional base excitations with gradually increasing acceleration amplitudes. This paper presents the dynamic characteristics, the seismic responses and the failure mechanism of the structure. The test results demonstrate that the structural system is a good solution to withstand earthquakes. The inter-storey drift and the overall behaviour meet the requirements of Chinese Design Code. Furthermore, weak positions under seldom-occurred earthquakes of seismic design intensity 8 are found based on the visible damages on the testing model, and some corresponding suggestions are proposed for the engineering design of the structure under extremely strong earthquake. Copyright © 2006 John Wiley & Sons, Ltd. [source]


    Response to three-component seismic motion of arbitrary direction

    EARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 1 2002
    Julio J. Hernández
    Abstract This paper presents a response spectrum analysis procedure for the calculation of the maximum structural response to three translational seismic components that may act at any inclination relative to the reference axes of the structure. The formula GCQC3, a generalization of the known CQC3-rule, incorporates the correlation between the seismic components along the axes of the structure and the intensity disparities between them. Contrary to the CQC3-rule where a principal seismic component must be vertical, in the GCQC3-rule all components can have any direction. Besides, the GCQC3-rule is applicable if we impose restrictions to the maximum inclination and/or intensity of a principal seismic component; in this case two components may be quasi-horizontal and the third may be quasi-vertical. This paper demonstrates that the critical responses of the structure, defined as the maximum and minimum responses considering all possible directions of incidence of one seismic component, are given by the square root of the maximum and minimum eigenvalues of the response matrix R, of order 3×3, defined in this paper; the elements of R are established on the basis of the modal responses used in the well-known CQC-rule. The critical responses to the three principal seismic components with arbitrary directions in space are easily calculated by combining the eigenvalues of R and the intensities of those components. The ratio rmax/rSRSS between the maximum response and the SRSS response, the latter being the most unfavourable response to the principal seismic components acting along the axes of the structure, is bounded between 1 and ,(3,a2/(,a2 + ,b2 + ,c2)), where ,a,,b,,c are the relative intensities of the three seismic components with identical spectral shape. Copyright © 2001 John Wiley & Sons, Ltd. [source]