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Dynamic
Kinds of Dynamic Terms modified by Dynamic Selected AbstractsDynamic data replication in LCG 2008CONCURRENCY AND COMPUTATION: PRACTICE & EXPERIENCE, Issue 11 2008C. Nicholson Abstract To provide performance access to data from high-energy physics experiments such as the Large Hadron Collider (LHC), controlled replication of files among grid sites is required. Dynamic, automated replication in response to jobs may also be useful and has been investigated using the grid simulator OptorSim. In this paper, results are presented from simulations of the LHC Computing Grid in 2008, in a physics analysis scenario. These show, first, that dynamic replication does give improved job throughput; second, that for this complex grid system, simple replication strategies such as Least Recently Used and Least Frequently Used are as effective as more advanced economic models; third, that grid site policies that allow maximum resource sharing are more effective; and lastly, that dynamic replication is particularly effective when data access patterns include some files being accessed more often than others, such as with a Zipf-like distribution. Copyright © 2008 John Wiley & Sons, Ltd. [source] Sustainable Development and the Sustainability of Competitive Advantage: A Dynamic and Sustainable View of the FirmCREATIVITY AND INNOVATION MANAGEMENT, Issue 3 2002Miguel A. Rodriguez Does the need for sustainable development hinder businesses' ability to create value? Is a firm's competitiveness negatively affected by considering that need? After quickly reviewing the main literature contributions on the relationship between business and society, and drawing from resource-based view of the firm and sustainable development literature, this paper presents a proposal for a dynamic and sustainable view of the firm. It shows how considering the changes introduced into the competitive landscape by sustainable development influences the way in which companies develop their resources, capabilities and activities, fostering the persistence of competitive advantages based on knowledge and innovation. [source] Natural and accidental torsion in one-storey structures on elastic foundation under non-vertically incident SH-wavesEARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 7 2006Javier Avilés Abstract Factors , and , used in equivalent static analysis to account for natural and accidental torsion are evaluated with consideration of soil,structure interaction. The combined torsional effects of structural asymmetry and foundation rotation are examined with reference to a single monosymmetric structure placed on a rigid foundation that is embedded into an elastic half-space, under to the action of non-vertically incident SH waves. Dynamic and accidental eccentricities are developed such that when used together with the code-specified base shear, the resulting static displacement at the flexible edge of the building is identical to that computed from dynamic analysis. It is shown that these eccentricities do not have a unique definition because they depend on both the selection of the design base shear and the criterion used for separation of the torsional effects of foundation rotation from those of structural asymmetry. Selected numerical results are presented in terms of dimensionless parameters for their general application, using a set of appropriate earthquake motions for ensuring generality of conclusions. The practical significance of this information for code-designed buildings is elucidated. Copyright © 2006 John Wiley & Sons, Ltd. [source] Nested distributions of bat flies (Diptera: Streblidae) on Neotropical bats: artifact and specificity in host-parasite studiesECOGRAPHY, Issue 3 2009Bruce D. Patterson We examined the structure of ectoparasitic bat fly infestations on 31 well-sampled bat species, representing 4 Neotropical families. Sample sizes varied from 22 to 1057 bats per species, and bat species were infested by 4 to 27 bat fly species. Individual bats supported smaller infracommunities (the set of parasites co-occurring on an individual host), ranging from 1 to 5 fly species in size, and no bat species had more than 6 bat fly species characteristically associated with it (its primary fly species). Nestedness analyses used system temperature (BINMATNEST algorithm) because it is particularly well-suited for analysis of interaction networks, where parasite records may be nested among hosts and host individuals simultaneously nested among parasites. Most species exhibited very low system temperatures (mean 3.14°; range 0.14,12.28°). Simulations showed that nested structure for all 31 species was significantly stronger than simulated values under 2 of the 3 null hypotheses, and about half the species were also nested under the more stringent conditions of the third null hypothesis. Yet this structure disappears when analyses are restricted to "primary" associations of fly species (flies on their customary host species), which exclude records thought to be atypical, transient, or potential contaminants. Despite comprising a small fraction of total parasite records, such anomalies represent a considerable part of the statistical state-space, offering the illusion of significant ecological structure. Only well understood and well documented systems can make distinctions between primary and other occurrence records. Generally, nestedness appears best developed in host-parasite systems where infestations are long-term and accumulate over time. Dynamic, short-term infestations by highly mobile parasites like bat flies may appear to be nested, but such structure is better understood in terms of host specificity and accidental occurrences than in terms of prevalence, persistence, or hierarchical niche relations of the flies. [source] Dynamic two state stochastic models for ecological regime shiftsENVIRONMETRICS, Issue 8 2009Jan Kloppenborg Mřller Abstract A simple non-linear stochastic two state, discrete-time model is presented. The interaction between benthic and pelagic vegetation in aquatic ecosystems subject to changing external nutrient loading is described by the non-linear functions. The dynamical behavior of the deterministic part of the model illustrates that hysteresis effect and regime shifts can be obtained for a limited range of parameter values only. The effect of multiplicative noise components entering at different levels of the model is presented and discussed. Including noise leads to very different results on the stability of regimes, depending on how the noise propagates through the system. The dynamical properties of a system should therefore be described through propagation of the state distributions rather than the state means and consequently, stochastic models should be compared in a probabilistic framework. Copyright © 2008 John Wiley & Sons, Ltd. [source] Body Position and Cardiac Dynamic and Chronotropic Responses to Steady-State Isocapnic Hypoxaemia in HumansEXPERIMENTAL PHYSIOLOGY, Issue 2 2000S. Deborah Lucy Neural mediation of the human cardiac response to isocapnic (IC) steady-state hypoxaemia was investigated using coarse-graining spectral analysis of heart rate variability (HRV). Six young adults were exposed in random order to a hypoxia or control protocol, in supine and sitting postures, while end-tidal PCO2 (PET,CO2) was clamped at resting eucapnic levels. An initial 11 min period of euoxia (PET,O2 100 mmHg; 13.3 kPa) was followed by a 22 min exposure to hypoxia (PET,O2 55 mmHg; 7.3 kPa), or continued euoxia (control). Harmonic and fractal powers of HRV were determined for the terminal 400 heart beats in each time period. Ventilation was stimulated (P < 0.05) and cardiac dynamics altered only by exposure to hypoxia. The cardiac interpulse interval was shortened (P < 0.001) similarly during hypoxia in both body positions. Vagally mediated high-frequency harmonic power (Ph) of HRV was decreased by hypoxia only in the supine position, while the fractal dimension, also linked to cardiac vagal control, was decreased in the sitting position (P < 0.05). However, low-frequency harmonic power (Pl) and the HRV indicator of sympathetic activity (Pl/Ph) were not altered by hypoxia in either position. These results suggest that, in humans, tachycardia induced by moderate IC hypoxaemia (arterial O2 saturation Sa,O2, 85%) was mediated by vagal withdrawal, irrespective of body position and resting autonomic balance, while associated changes in HRV were positionally dependent. [source] Anxiety and the True Beginner,False Beginner Dynamic in Beginning French and Spanish ClassesFOREIGN LANGUAGE ANNALS, Issue 2 2005Diana Frantzen Abstract: This study considered true beginners and false beginners in first-semester university French and Spanish classes to: (a) determine whether true beginners and false beginners differ in anxiety, grades, and plans to continue language study; and (b) identify classroom factors that foster anxiety or comfort. Students completed a questionnaire that included the Foreign Language Classroom Anxiety Scale (Horwitz, Horwitz, & Cope, 1986), MacIntyre and Gardner Anxiety Subscales (1989, 1994), demographic information, grade expectations, and open-ended questions. Randomly selected students were interviewed about their experiences in the courses. Statistical analyses revealed that (a) although neither group was terribly anxious, true beginners were significantly more anxious overall and during processing and output stages than false beginners; (b) true beginners expected and received lower grades than false beginners; and (c) significantly more true beginners than false beginners planned to continue studying the language. Comments on one written open-ended question and in the interviews pointed to the key role of the instructor in reducing anxiety. [source] Dynamic versus static models in cost-effectiveness analyses of anti-viral drug therapy to mitigate an influenza pandemicHEALTH ECONOMICS, Issue 5 2010Anna K. Lugnér Abstract Conventional (static) models used in health economics implicitly assume that the probability of disease exposure is constant over time and unaffected by interventions. For transmissible infectious diseases this is not realistic and another class of models is required, so-called dynamic models. This study aims to examine the differences between one dynamic and one static model, estimating the effects of therapeutic treatment with antiviral (AV) drugs during an influenza pandemic in the Netherlands. Specifically, we focus on the sensitivity of the cost-effectiveness ratios to model choice, to the assumed drug coverage, and to the value of several epidemiological factors. Therapeutic use of AV-drugs is cost-effective compared with non-intervention, irrespective of which model approach is chosen. The findings further show that: (1) the cost-effectiveness ratio according to the static model is insensitive to the size of a pandemic, whereas the ratio according to the dynamic model increases with the size of a pandemic; (2) according to the dynamic model, the cost per infection and the life-years gained per treatment are not constant but depend on the proportion of cases that are treated; and (3) the age-specific clinical attack rates affect the sensitivity of cost-effectiveness ratio to model choice. Copyright © 2009 John Wiley & Sons, Ltd. [source] Dynamic and Reversible Organization of Zeolite L Crystals Induced by Holographic Optical TweezersADVANCED MATERIALS, Issue 37 2010Mike Woerdemann Organization and patterning of zeolite L crystals with their unique properties such as their one-dimensional nano channel system is of highest topical interest with various applications in many areas of science. We demonstrate full three-dimensional optical control of single zeolite L crystals and for the first time fully reversible, dynamic organization of a multitude of individually controlled zeolite L crystals. [source] Incubation phase of acute hepatitis B in man: Dynamic of cellular immune mechanismsHEPATOLOGY, Issue 5 2000George J.M. Webster After hepatitis B virus (HBV) infection, liver injury and viral control have been thought to result from lysis of infected hepatocytes by virus-specific cytotoxic T cells. Patients are usually studied only after developing significant liver injury, and so the viral and immune events during the incubation phase of disease have not been defined. During a single-source outbreak of HBV infection, we identified patients before the onset of symptomatic hepatitis. The dynamics of HBV replication, liver injury, and HBV-specific CD8+ and CD4+ cell responses were investigated from incubation to recovery. Although a rise in alanine transaminase (ALT) levels was present at the time of the initial fall in HBV-DNA levels, maximal reduction in virus level occurred before significant liver injury. Direct ex vivo quantification of HBV-specific CD4+ and CD8+ cells, by using human leukocyte antigen (HLA) class I tetramers and intracellular cytokine staining, showed that adaptive immune mechanisms are present during the incubation phase, at least 4 weeks before symptoms. The results suggest that the pattern of reduction in HBV replication is not directly proportional to tissue injury during acute hepatitis B in humans. Furthermore, because virus-specific immune responses and significant reductions in viral replication are seen during the incubation phase, it is likely that the immune events central to viral control occur before symptomatic disease. [source] Enzyme-Responsive Hydrogels: Dynamic, 3D-Pattern Formation Within Enzyme-Responsive Hydrogels (Adv. Mater.ADVANCED MATERIALS, Issue 41 200941/2009) On p. 4148, Sarah Heilshorn and Karin Straley demonstrate the design of a family of adaptive protein polymers with highly tunable and predictable degradation rates suitable for complex tissue-engineering applications. The cover image shows fluorescently labeled neurons grow and extend neurites on a protein-engineered biomaterial. Enzymes secreted by the neurons trigger selective degradation of specific regions of the biomaterial, allowing dynamic 3D patterns to emerge over time. Microscope images were acquired by Karin Straley. Digital art by Chelsea Castillo. [source] Dynamic, 3D-Pattern Formation Within Enzyme-Responsive HydrogelsADVANCED MATERIALS, Issue 41 2009Karin S. Straley Dynamic, 3D hydrogel patterns emerge over time in response to cell-secreted enzymes (see image). Composite hydrogels fabricated from engineered proteins exhibit customized half-lives ranging across two orders of magnitude due to slight changes in the primary amino acid sequence. The evolution of internal 3D void structures within these polymeric materials is used to release multiple payload molecules with distinct spatial and temporal delivery profiles. [source] Onset characteristics of the southwest monsoon over IndiaINTERNATIONAL JOURNAL OF CLIMATOLOGY, Issue 2 2005P. V. S. Raju Abstract Dynamic and thermodynamic characteristics of the Asian summer monsoon during the onset phase over the Indian Peninsula (Kerala coast) and its variability are examined with reanalysis data sets. For this study, daily averaged (0000 and 1200 UTC) reanalysis data sets of National Centre for Environmental Prediction,National Centre for Atmospheric Research for the period 1948,99 are used. Based on 52 years of onset dates of the Indian summer monsoon, we categorized pre-onset, onset and post-onset periods (each averaged 5 days) to investigate the mean circulation characteristics and the large-scale energetics of the Asian summer monsoon. It is found that the strength of the low-level Somali jet and upper tropospheric tropical easterly jet increase rapidly during the time of evolution of the summer monsoon over India. Over the Bay of Bengal and the Arabian Sea, predominant changes are noticed in the large-scale balances of kinetic energy, heat and moisture from the pre-onset to the post-onset periods. Prior to the onset of the summer monsoon over India, a zone of flux convergence of heat and moisture is noticed over the eastern sector of the Bay of Bengal and this intensifies in the onset and post-onset periods. During onset of the monsoon over India, the horizontal flux convergence of heat and moisture, as well as diabatic heating, are enhanced over the Arabian Sea. These subsequently increase with the evolution and advancement of the monsoon over India. Further, the dynamics of the evolution processes (15 days before and 30 days after the onset date of the monsoon over Kerala for each annual cycle) are studied over various sectors, such as the Arabian Sea, Bay of Bengal and Indian Peninsula region. The study reveals that the low-level kinetic energy, vertically integrated generation of kinetic energy and net tropospheric moisture over Arabian Sea can be used as potential predictors for the prediction of the possible onset date of the summer monsoon over the Indian Peninsula. Copyright © 2005 Royal Meteorological Society [source] Dynamic fade restoration in Ka-band satellite systemsINTERNATIONAL JOURNAL OF SATELLITE COMMUNICATIONS AND NETWORKING, Issue 4 2002A. Paraboni Atmospheric precipitation can seriously affect the propagation of centimeter and millimeter electromagnetic waves. As a consequence, in some applications, it is necessary to make use of a fade countermeasure technique in order to satisfy the system availability and quality requirements. This study analyses the performance of a satellite-based system in geo-stationary orbit operating at 20 GHz, dynamically assigning the antenna directivity pattern to counteract tropospheric attenuation. The on-board power is spatially distributed over the covered region to minimize, at any time, the number of users undergoing outage because of the tropospheric attenuation. Both the aspects of broadcasting and telecommunication services are addressed. The reflector antenna of the system is supposed to be illuminated by a cluster of feeds driven by a set of excitation coefficients, continuously modified and optimized according to the meteorological information derived by processing METEOSAT satellite data and ECMWF (European Centre for Medium-Range Weather Forecasts) data. Copyright © 2002 John Wiley & Sons, Ltd. [source] Rheological and thermal properties of poly(ethylene oxide)/multiwall carbon nanotube compositesJOURNAL OF APPLIED POLYMER SCIENCE, Issue 4 2008T. N. Abraham Abstract Poly(ethylene oxide) (PEO) based nanocomposites were prepared by the dispersion of multiwall carbon nanotubes (MWCNTs) in aqueous solution. MWCNTs were added up to 4 wt % of the PEO matrix. The dynamic viscoelastic behavior of the PEO/MWCNT nanocomposites was assessed with a strain-controlled parallel-plate rheometer. Prominent increases in the shear viscosity and storage modulus of the nanocomposites were found with increasing MWCNT content. Dynamic and isothermal differential scanning calorimetry studies indicated a significant decrease in the crystallization temperature as a result of the incorporation of MWCNTs; these composites can find applications as crystallizable switching components for shape-memory polymer systems with adjustable switching temperatures. The solid-state, direct-current conductivity was also enhanced by the incorporation of MWCNTs. The dispersion level of the MWCNTs was investigated with scanning electron microscopy. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] Sorption of copper by a highly mineralized peat in batch and packed-bed systemsJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 2 2010Marta Izquierdo Abstract BACKGROUND: The performance of peat for copper sorption was investigated in batch and fixed-bed experiments. The effect of pH was evaluated in batch experiments and the experimental data were fitted to an equilibrium model including pH dependence. Hydrodynamic axial dispersion was estimated by tracing experiments using LiCl as a tracer. Six fixed-bed experiments were carried out at copper concentrations between 1 and 60 mg dm,3 and the adsorption isotherm in dynamic mode was obtained. A mass transport model including convection,dispersion and sorption processes was applied for breakthrough curve modelling. RESULTS: Maximum uptake capacities in batch mode were 22.0, 36.4, and 43.7 mg g,1 for pH values of 4.0, 5.0, and 6.0, respectively. Uptake capacities in continuous flow systems varied from 36.5 to 43.4 mg g,1 for copper concentrations between 1 and 60 mg dm,3. Dynamic and batch isotherms showed different shapes but a similar maximum uptake capacity. Sorbent regeneration was successfully performed with HCl. A potential relationship between dispersion coefficient and velocity was obtained with dispersion coefficients between 5.00 × 10,8 and 2.95 × 10,6 m2 s,1 for water velocities ranging between 0.56 × 10,4 and 5.03 × 10,4 m s,1. The mass transport model predicted both the breakpoints and the shape of the breakthrough curves. CONCLUSIONS: High retention capacities indicate that peat can be used as an effective sorbent for the treatment of wastewater containing copper ions. Copyright © 2009 Society of Chemical Industry [source] High-b-value diffusion-weighted MR imaging of hepatocellular lesions: Estimation of grade of malignancy of hepatocellular carcinomaJOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 5 2009Ali Muhi MD Abstract Purpose: To evaluate the effectiveness of diffusion-weighted magnetic resonance imaging (DWI) in estimating the grade of malignancy of hepatocellular carcinoma. Materials and Methods: Dynamic contrast-enhanced computed tomography (CE-CT) and DWI (b value, 1000 s/mm2) were performed on 73 patients. Using DW images, the lesions were classified as "visible" or "invisible." The apparent diffusion coefficient (ADC) of the lesions was measured. Furthermore, the lesions were classified as hypervascular or iso-hypovascular using arterial phase CE-CT images. The image findings for each lesion type were compared. Results: The 73 patients had 98 hepatocellular lesions, of which 12 were histologically diagnosed as dysplastic nodules; 39, well-differentiated HCCs; 33, moderately differentiated HCCs; and 14, poorly differentiated HCCs. The mean ADC values of moderately poorly-differentiated HCCs were significantly lower than well-differentiated HCCs and dysplastic nodules (P < 0.01). On DW images, >90% of moderately (30/33) and poorly differentiated HCCs (13/14) were visible, while 51% of well-differentiated HCCs (20/39) and all dysplastic nodules were invisible. Of 22 iso-hypovascular lesions, 4 were visible on DW images and were poorly differentiated HCCs, whereas 18 were invisible and were dysplastic nodules (12/18) or well-differentiated HCCs (6/18). Conclusion: A combination of hypovascularity and visibility on DW images can help distinguish poorly differentiated HCCs from low-grade hepatocellular lesions (dysplastic nodules and well-differentiated HCCs). J. Magn. Reson. Imaging 2009;30:1005,1011. © 2009 Wiley-Liss, Inc. [source] Understanding the Search for Meaning in Life: Personality, Cognitive Style, and the Dynamic Between Seeking and Experiencing MeaningJOURNAL OF PERSONALITY, Issue 2 2008Michael F. Steger ABSTRACT Although several theories assert that understanding the search for meaning in life is important, empirical research on this construct is sparse. Three studies provide the first extensive effort to understand the correlates of the search for meaning in a multistudy research program. Assessed were relations between search for meaning and well-being, cognitive style, and the Big Five, Big Three, Approach/Avoidance, and Interest models of personality, with a particular emphasis on understanding the correlates of search for meaning that are independent of presence of meaning. Conceptual models of the relation between search and presence were tested. Findings suggest that people lacking meaning search for it; the search for meaning did not appear to lead to its presence. Study 3 found that basic motive dispositions moderated relations between search for meaning and its presence. Results highlight the importance of basic personality dispositions in understanding the search for meaning and its correlates. [source] Dynamic and evolutionary updates of classificatory schemes in scientific journal structuresJOURNAL OF THE AMERICAN SOCIETY FOR INFORMATION SCIENCE AND TECHNOLOGY, Issue 12 2002Loet Leydesdorff Can the inclusion of new journals in the Science Citation Index be used for the indication of structural change in the database, and how can this change be compared with reorganizations of relations among previously included journals? Change in the number of journals (n) is distinguished from change in the number of journal categories (m). Although the number of journals can be considered as a given at each moment in time, the number of journal categories is based on a reconstruction that is time-stamped ex post. The reflexive reconstruction is in need of an update when new information becomes available in a next year. Implications of this shift towards an evolutionary perspective are specified. [source] Dynamic and generalized Wentzell node conditions for network equationsMATHEMATICAL METHODS IN THE APPLIED SCIENCES, Issue 6 2007Delio Mugnolo Abstract Motivated by a neurobiological problem, we discuss a class of diffusion problems on a network. The celebrated Rall lumped soma model for the spread of electrical potential in a dendritical tree prescribes that the common cable equation must be coupled with particular dynamic conditions in some nodes (the cell bodies, or somata). We discuss the extension of this model to the case of a whole network of neurons, where the ramification nodes can be either active (with excitatory time-dependent boundary conditions) or passive (where no dynamics take place, i.e. only Kirchhoff laws are imposed). While well-posedness of the system has already been obtained in previous works, using abstract tools based on variational methods and semigroup theory we are able to prove several qualitative properties, including asymptotic behaviour, regularity of solutions, and monotonicity of the semigroups in dependence on the physical coefficients. Copyright © 2006 John Wiley & Sons, Ltd. [source] The Iraqi Military Re-enters the Gulf Security DynamicMIDDLE EAST POLICY, Issue 3 2009Eric V. Thompson [source] ASNE Day 2004; National Program Committee; ASNE's Dynamic 2004,2005 Symposium ProgramNAVAL ENGINEERS JOURNAL, Issue 2 2004Dave Sargent RADM USN (Ret.) No abstract is available for this article. [source] Threshold optimization for weighted voting classifiersNAVAL RESEARCH LOGISTICS: AN INTERNATIONAL JOURNAL, Issue 4 2003G. Levitin Abstract Weighted voting classifiers considered in this paper consist of N units each providing individual classification decisions. The entire system output is based on tallying the weighted votes for each decision and choosing the one which has total support weight exceeding a certain threshold. Each individual unit may abstain from voting. The entire system may also abstain from voting if no decision support weight exceeds the threshold. Existing methods of evaluating the reliability of weighted voting systems can be applied to limited special cases of these systems and impose some restrictions on their parameters. In this paper a universal generating function method is suggested which allows the reliability of weighted voting classifiers to be exactly evaluated without imposing constraints on unit weights. Based on this method, the classifier reliability is determined as a function of a threshold factor, and a procedure is suggested for finding the threshold which minimizes the cost of damage caused by classifier failures (misclassification and abstention may have different price.) Dynamic and static threshold voting rules are considered and compared. A method of analyzing the influence of units' availability on the entire classifier reliability is suggested, and illustrative examples are presented. © 2003 Wiley Periodicals, Inc. Naval Research Logistics 50: 322,344, 2003. [source] Evaluation of the anti-vascular effects of combretastatin in rodent tumours by dynamic contrast enhanced MRINMR IN BIOMEDICINE, Issue 2 2002Ross J. Maxwell The anti-vascular effects of the tubulin binding agent, disodium combretastatin A-4 3- O -phosphate (CA-4-P), have been investigated in the rat P22 carcinosarcoma by measurements of radiolabelled iodoantipyrine uptake and dynamic contrast-enhanced MRI. The iodoantipyrine estimates of absolute tumour blood flow showed a reduction from 0.35 to 0.04,ml g,1 min,1 6,h after 10,mg kg,1 CA-4-P and to <0.01,ml g,1 min,1 after 100,mg kg,1. Tumour blood flow recovered to control values 24,h after 10,mg kg,1 CA-4-P, but there was no recovery by 24,h after the higher dose. Dynamic contrast-enhanced MR images were obtained at 4.7 T, following injection of 0.1,mmol kg,1 Gd-DTPA and analysed assuming a model arterial input function. A parameter, Ktrans, which is related to blood flow rate and permeability of the tumour vasculature to Gd-DTPA, was calculated from the uptake data. Ktrans showed a reduction from 0.34 to 0.11 min,1 6,h after 10,mg kg,1 CA-4-P and to 0.07 min,1 after 100,mg kg,1. Although the magnitude of changes in Ktrans was smaller than that in tumour blood flow, the time course and dose-dependency patterns were very similar. The apparent extravascular extracellular volume fraction, ,e, showed a four-fold reduction 6,h after 100,mg kg,1 CA-4-P, possibly associated with vascular shutdown within large regions of the tumour. These results suggest that Ktrans values for Gd-DTPA uptake into tumours could be a useful non-invasive indicator of blood flow changes induced by anti-vascular agents such as combretastatin. Copyright © 2002 John Wiley & Sons, Ltd. [source] Dynamic ,back-off' analysis: use of piecewise linear approximationsOPTIMAL CONTROL APPLICATIONS AND METHODS, Issue 2 2003José L. Figueroa Abstract The operating point of a process is usually computed by optimizing an objective function, e.g. the profit, subject to some plant characteristics. Typically, the resulting point lies on the boundary of the operating region. At this point, the presence of disturbances can easily cause constraint violations and make the process move to the unfeasible region. Then, it is necessary to move the operating point away into the feasible region by considering the effect that the expected disturbances will have on the operation of the plant. The purpose of this paper is to present an efficient algorithm to modify the operating point in order to keep feasibility (both in steady-state and along transitory) in the process operation against the disturbances. Copyright © 2003 John Wiley & Sons, Ltd. [source] Dynamic and capillary rheology of LDPE-EVA,based thermoplastic elastomer: Effect of silica nanofillerPOLYMER COMPOSITES, Issue 3 2010Shalmali Hui The effect of pristine silica nanoparticles on the dynamic and capillary rheology of a model LDPE-EVA thermoplastic elastomeric system is explored in this paper. The pristine silica nanoparticles were melt-blended with the LDPE-EVA system at 1.5, 3, and 5 wt% loadings, respectively, by varying the sequence of addition. In one of the compositions, coupling agent bis-[3-(triethoxysilyl)propyl] tetrasulphide (Si-69) was used to improve the interaction of hydrophilic silica particles with polymer matrix. Results obtained reveal that the viscoelastic behavior of such composites is influenced remarkably by loadings of silica, variation of sequence, and addition of Si-69. Upon addition of coupling agent, G, value increases especially at higher strain levels due to increased polymer-filler interactions. All systems with various loading of nanosilica represent an increase in elastic response with increasing frequency. Both the unfilled and filled blends exhibit rheological behavior of non-Newtonian fluids. But interestingly, the viscoelastic response varies markedly with the temperature. The dynamic and steady shear rheological properties register a good correlation in regard to the viscous vs. elastic response of such systems. Finally, the rheological behavior is correlated with morphology of the present system processed at various shear rates. POLYM. COMPOS., 2010. © 2009 Society of Plastics Engineers [source] Dynamic of Destruction: Culture and Mass Killing in the First World War , By Alan KramerTHE HISTORIAN, Issue 4 2009Barbara C. Allen No abstract is available for this article. [source] Dynamic or Static Capabilities?THE JOURNAL OF PRODUCT INNOVATION MANAGEMENT, Issue 5 2009Process Management Practices, Response to Technological Change Whether and how organizations adapt to changes in their environments has been a prominent theme in organization and strategy research. Within this research, there is controversy about whether organizational routines hamper or facilitate adaptation. Organizational routines give rise to inertia but are also the vehicles for change in recent work on dynamic capabilities. This rising interest in routines in research coincides with an increase in management practices focused on organizational routines and processes. This study explores how the increasing use of process management practices affected organizational response to a major technological change through new product developments. The empirical setting is the photography industry over a decade, during the shift from silver-halide chemistry to digital technology. The advent and rise of practices associated with the new ISO 9000 certification program in the 1990s coincided with increasing technological substitution in photography, allowing for assessing how increasing attention to routines through ISO 9000 practices over time affected ongoing responsiveness to the technological change. The study further compares the effects for the incumbent firms in the existing technology with nonincumbent firms entering from elsewhere. Relying on longitudinal panel data models as well as hazard models, findings show that greater process management practices dampened response to new generations of digital technology, but this effect differed for incumbents and nonincumbents. Increasing use of process management practices over time had a greater negative effect on incumbents' response to the rapid technological change. The study contributes to research in technological change by highlighting specific management practices that may create disconnects between firms' capabilities and changing environments and disadvantage incumbents in the face of radical technological change. This research also contributes to literature on organizational routines and capabilities. Studying the effects of increasing ISO 9000 practices undertaken in firms provides an opportunity to gauge the effects of systematic routinization of organizational activities and their effects on adaptation. This research also contributes to management practice. The promise of process management is to help firms adapt to changing environments, and, as such, managers facing technological change may adopt process management practices as a response to uncertainty and change. But managers must more fully understand the potential benefits and risks of process management to ensure these practices are used in the appropriate contexts. [source] Dynamic and spatial models of kelp forest of Macrocystis integrifolia and Lessonia trabeculata (SE Pacific) for assessment harvest scenarios: short-term responsesAQUATIC CONSERVATION: MARINE AND FRESHWATER ECOSYSTEMS, Issue 5 2010Marco Ortiz Abstract 1. Dynamic and spatial models of the kelp forest off northern Chile (SE Pacific coast) were constructed using the Ecosim and Ecospace theoretical frameworks based on a previously mass-balanced trophic model using Ecopath II software. 2. The biomass of Macrocystis integrifolia and Lessonia trabeculata blades constituted the most relevant compartments or variables of the ecosystem studied. 3. The relative ascendency (A/C) of 35.5% suggests that this ecosystem is immature, but resistant to disturbances (e.g. fisheries). 4. The results obtained using mixed trophic impacts (MTI) show that both brown macroalgae produced relatively similar quantitative and qualitative effects, however, the predictions based on Ecosim clearly show that L. trabeculata experienced the most relevant direct and indirect effects. 5. The highest values of system recovery time obtained by Pinguipes chilensis and the other seastar group suggest that both compartments could be considered to be top predator species with strong top-down control. 6. The exploitation of kelp blades as a new harvest strategy appears to be ecologically sustainable. 7. The Ecospace trophic-spatially explicit model shows that exploitation exerted separately by habitat generates a similar pattern of direct and indirect effects. These results suggest that a habitat rotation of fisheries would not be justified.Copyright © 2010 John Wiley & Sons, Ltd. [source] Strategic issues in global climate change policy,AUSTRALIAN JOURNAL OF AGRICULTURAL & RESOURCE ECONOMICS, Issue 2 2010Harry Clarke An analysis of prospects for deriving self-enforcing, global, greenhouse gas emission mitigation agreements is provided. Policy spillovers and carbon leakages are accounted for. Situations where mitigation effort should be concentrated in particular countries and where efficient outcomes can be fostered by international trade in emissions permits are discussed. The use of auxiliary policies to transform intractable Prisoner's Dilemma incentive problems to more tractable problems, the role of policy commitments and the strategic implications of ,no regret' and ,adaptation' policies are analysed. Dynamic and repeated game formulations are outlined. [source] | |||||||||||||||||||||||||||||||||||||||||||