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Sample records for cellular growth rate

  1. Asymptotic Cellular Growth Rate as the Effective Information Utilization Rate

    CERN Document Server

    Pugatch, Rami; Tlusty, Tsvi

    2013-01-01

    We study the average asymptotic growth rate of cells in randomly fluctuating environments. Using a game-theoretic perspective, we show that any response strategy has an asymptotic growth rate, which is the sum of: (i) the maximal growth rate at the worst possible distribution of environments, (ii) relative information between the actual distribution of environments to the worst one, and (iii) information utilization rate which is the information rate of the sensory devices minus the "information dissipation rate", the amount of information not utilized by the cell for growth. In non-stationary environments, the optimal strategy is the time average of the instantaneous optimal strategy and the optimal switching times are evenly spaced in the statistical (Fisher) metric.

  2. Inhibition of Cellular Growth of Melanoma Cells Line by Heterogeneous Beta Chronic Irradiation at Very Low-Dose-Rate

    International Nuclear Information System (INIS)

    Radioisotopes that decay via beta emission are widely used in science and medicine. The main advantage of beta-emitters is the relatively long path length in biological tissue (in the mm range). The objective of this work was to determine the inhibition of cellular growth of melanoma cells (melanoma cells are one of the most radioresistant tumor cells) by beta irradiation at very low dose rate using a simple and economic device. This irradiation system represents a situation similar to radiodiagnostic, radioimmunotherapy and brachytherapy because there is a continuous emission of exponentially decreasing low-dose-rate irradiation with heterogeneous dose deposition. It permitted us to study different dose rates changing only the activity of beta emitter. We compare it with the high dose rate gamma irradiation. (authors)

  3. Predicting Cellular Growth from Gene Expression Signatures

    OpenAIRE

    Dunham, Maitreya J.; Troyanskaya, Olga G.; Airoldi, Edoardo; Broach, James R.; Caudy, Amy A.; Gresham, David; Botstein, David; Huttenhower, Curtis; Lu, Charles

    2009-01-01

    Maintaining balanced growth in a changing environment is a fundamental systems-level challenge for cellular physiology, particularly in microorganisms. While the complete set of regulatory and functional pathways supporting growth and cellular proliferation are not yet known, portions of them are well understood. In particular, cellular proliferation is governed by mechanisms that are highly conserved from unicellular to multicellular organisms, and the disruption of these processes in metazo...

  4. Survival of Phenotypic Information during Cellular Growth Transitions.

    Science.gov (United States)

    Ray, J Christian J

    2016-08-19

    Phenotypic memory can predispose cells to physiological outcomes, contribute to heterogeneity in cellular populations, and allow computation of environmental features, such as nutrient gradients. In bacteria and synthetic circuits in general, memory can often be set by protein concentrations: because of the relative stability of proteins, the degradation rate is often dominated by the growth rate, and inheritance is a significant factor. Cells can then be primed to respond to events that recur with frequencies faster than the time to eliminate proteins. Protein memory can be extended if cells reach extremely low growth rates or no growth. Here we characterize the necessary time scales for different quantities of protein memory, measured as relative entropy (Kullback-Leibler divergence), for a variety of cellular growth arrest transition dynamics. We identify a critical manifold in relative protein degradation/growth arrest time scales where information is, in principle, preserved indefinitely because proteins are trapped at a concentration determined by the competing time scales as long as nongrowth-mediated protein degradation is negligible. We next asked what characteristics of growth arrest dynamics and initial protein distributions best preserve or eliminate information about previous environments. We identified that sharp growth arrest transitions with skewed initial protein distributions optimize flexibility, with information preservation and minimal cost of residual protein. As a result, a nearly memoryless regime, corresponding to a form of bet-hedging, may be an optimal strategy for storage of information by protein concentrations in growth-arrested cells. PMID:26910476

  5. Cellular automata simulations on nanocrystallization processes: From instantaneous growth approximation to limited growth

    OpenAIRE

    Blázquez, J.S.; Conde, C. F.; Conde, A.

    2011-01-01

    Cellular automata simulations have been performed to simulate the crystallization process under a limited growth approximation. This approximation resembles several characteristics exhibited by nanocrystalline microstructures and nanocrystallization kinetics. Avrami exponent decreases from a value n = 4 indicating interface controlled growth and constant nucleation rate to a value n ~ 1 indicating absence of growth. A continuous change of the growth contribution to the Avrami exponent from ze...

  6. Slowdown of growth controls cellular differentiation.

    Science.gov (United States)

    Narula, Jatin; Kuchina, Anna; Zhang, Fang; Fujita, Masaya; Süel, Gürol M; Igoshin, Oleg A

    2016-01-01

    How can changes in growth rate affect the regulatory networks behavior and the outcomes of cellular differentiation? We address this question by focusing on starvation response in sporulating Bacillus subtilis We show that the activity of sporulation master regulator Spo0A increases with decreasing cellular growth rate. Using a mathematical model of the phosphorelay-the network controlling Spo0A-we predict that this increase in Spo0A activity can be explained by the phosphorelay protein accumulation and lengthening of the period between chromosomal replication events caused by growth slowdown. As a result, only cells growing slower than a certain rate reach threshold Spo0A activity necessary for sporulation. This growth threshold model accurately predicts cell fates and explains the distribution of sporulation deferral times. We confirm our predictions experimentally and show that the concentration rather than activity of phosphorelay proteins is affected by the growth slowdown. We conclude that sensing the growth rates enables cells to indirectly detect starvation without the need for evaluating specific stress signals. PMID:27216630

  7. Growth rate of nuclei

    Czech Academy of Sciences Publication Activity Database

    Kožíšek, Zdeněk; Demo, Pavel

    Bratislava: Slovak Society for Industrial Chemistry, 2015 - (Koman, M.; Jorík, V.; Kožíšek, Z.). s. 26-26 ISBN 978-80-89597-28-4. [Joint Seminar Development of Materials Science in Research and Education /25./. 31.08.2015-04.09.2015, Kežmarské Žľaby] R&D Projects: GA ČR GAP108/12/0891 Institutional support: RVO:68378271 Keywords : growth rate * nucleation Subject RIV: BM - Solid Matter Physics ; Magnetism

  8. Cellular automata modeling of cooperative eutectic growth

    Directory of Open Access Journals (Sweden)

    E. Olejnik

    2010-01-01

    Full Text Available The model and results of the 2D simulation of the cooperative growth of two phases in the lamellar eutectic are presented. The pro-posed model takes into account heat transfer, components diffusion and nonstationary concentration distribution in the liquid and solid phases, non-equlibrium nature of the phase transformation and kinetics of the growth, influence of the surface energy and interface curva-ture on the conditions of the thermodynamic equilibrium. For the determination of the phase interface shape the Cellular Automata tech-nique (CA was used. For the calculation of temperature and concentration distribution the numerical solution of the Fourier equation was used. The partial differential equations were solved by Finite Differences Method (FDM. The spatial position and cell sizes of CA lattice and FDM mesh are equal.Proposed model can predict the steady state growth with a constant interlamellar spacing in the regular plate eutectic, as well as some transient processes that bring to the changes of that parameters. Obtained simulation data show the solid-liquid interface changes result in the termination of lamella and enlargement of interlamellar spacing. Another simulation results illustrate a pocket formation in the center of one phase that forestalls nucleation (or intergrowth of the new lamellae of another phase. The data of the solidification study of the transparent material (CBr4 – 8,4% C2Cl6 obtained in the thin layer demonstrate the qualita-tive agreement of the simulation.

  9. GROWTH RATE OF ARABIAN FOALS

    Directory of Open Access Journals (Sweden)

    M. PIESZKA

    2013-12-01

    Full Text Available Arabian horses are treated as one of the most noble horse breed in the world. It isalso one of the oldest breed known as a root of many other breeds. Opposite toThoroughbred horses Arabian ones are very healthy, easy to keep with low fodderdemand. They are still incredibly resistant to environmental conditions. Growth anddevelopment of foals is also very interesting because it is more similar to growth ofprimitive than to noble foals. The object of this study was to analyse the growth rateof Arabian foals bred in Poland. 382 foals born in Bialka Stud in 1983-2003 weretaken under consideration. The height at withers, girth and cannon circumferencemeasured at 1 day and 6 and 18 months of life were analysed. On this base thegrowth rate was calculated. Horses were divided into different groups accordingtheir year of birth, sex, coat colour and sire and dam lines. The statistical differencesbetween particular groups were evaluated. It was stated that year of birth affectedsignificantly the growth rate of Arabian foals. Colts were characterized bysignificantly higher growth rate of cannon circumference. Horses of different coatcolour did not differ in growth rate of any parameter. Affiliation to particular sireand dam lines had some effects on growth rate of Arabian foals.

  10. Bounds on bacterial cell growth rates

    CERN Document Server

    Landy, Jonathan

    2013-01-01

    Recent experiments have shown that rod-like bacteria in nutrient-rich media grow in length at an exponential rate. Here, I point out that it is the elongated shape of these bacteria that allows for this behavior. Further, I show that when a bacterium's growth is limited by some nutrient -- taken in by the cell through a diffusion-to-capture process -- its growth is suppressed: In three-dimensional geometries, the length $L$ is bounded by $\\log L \\lesssim t^{1/2}$, while in two dimensions the length is bounded by a power-law form. Fits of experimental growth curves to these predicted, sub-exponential forms could allow for direct measures of quantities relating to cellular metabolic rates.

  11. Cellular automata modeling of cooperative eutectic growth

    OpenAIRE

    E. Olejnik; E. Fraś; D. Gurgul; A. Burbelko

    2010-01-01

    The model and results of the 2D simulation of the cooperative growth of two phases in the lamellar eutectic are presented. The pro-posed model takes into account heat transfer, components diffusion and nonstationary concentration distribution in the liquid and solid phases, non-equlibrium nature of the phase transformation and kinetics of the growth, influence of the surface energy and interface curva-ture on the conditions of the thermodynamic equilibrium. For the determination of the phase ...

  12. Perfect cellular eutectic growth in directionally solidified NiAl-Cr(Mo) hypereutectic alloy

    Science.gov (United States)

    Shang, Zhao; Shen, Jun; Zhang, Jianfei; Wang, Lei; Fu, Hengzhi

    2012-09-01

    Cellular eutectic microstructures with fully lamellar morphology were observed in the directionally solidified Ni-31Al-32Cr-6Mo (at%) hypereutectic alloy at withdrawal rates of 15, 25 and 50 μm/s, but the morphologies of cellular microstructures did not change consecutively with increasing withdrawal rate. The growth interfaces were deep cellular at withdrawal rates of 15 and 50 μm/s, but it changed to be shallow cellular at rate of 25 μm/s. The reason is that the interface undercooling comes to minimum at the middle rate of 25 μm/s. If the interface undercooling decreases, the tendency of constitutional undercooling will be weaken. The small constitutional undercooling will increase the interface stability, so that the interface morphology changes from deep cellular to shallow cellular. The shallow cellular growth interface led to a perfect cellular eutectic microstructure, which was analogous to the planar eutectic microstructure. In this case, the widths of the intercellular regions were narrowest, no coarse or irregular plates existed at the cell boundaries, and the thicknesses of the lamellae were almost uniform. The properties of the alloy may be markedly improved.

  13. GDP growth rate and population

    OpenAIRE

    Kitov, Ivan O.

    2005-01-01

    Real GDP growth rate in developed countries is found to be a sum of two terms. The first term is the reciprocal value of the duration of the period of mean income growth with work experience, Tcr. The current value of Tcr in the USA is 40 years. The second term is inherently related to population and defined by the relative change in the number of people with a specific age (9 years in the USA), (1/2)*dN9(t) /N9(t), where N9(t) is the number of 9-year-olds at time t. The Tcr grows as the squa...

  14. Analysis of blocking rate and bandwidth usage of mobile IPTV services in wireless cellular networks.

    Science.gov (United States)

    Li, Mingfu

    2014-01-01

    Mobile IPTV services over wireless cellular networks become more and more popular, owing to the significant growth in access bandwidth of wireless cellular networks such as 3G/4G and WiMAX. However, the spectrum resources of wireless cellular networks is rare. How to enhance the spectral efficiency of mobile networks becomes an important issue. Unicast, broadcast, and multicast are the most important transport schemes for offering mobile IPTV services over wireless cellular networks. Therefore, bandwidth usages and blocking rates of unicast, broadcast, and multicast IPTV services were analyzed and compared in this paper. Simulations were also conducted to validate the analytical results. Numerical results demonstrate that the presented analysis is correct, and multicast scheme achieves the best bandwidth usage and blocking rate performance, relative to the other two schemes. PMID:25379521

  15. A cellular automaton model for tumor growth in heterogeneous environment

    Science.gov (United States)

    Jiao, Yang; Torquato, Sal

    2011-03-01

    Cancer is not a single disease: it exhibits heterogeneity on different spatial and temporal scales and strongly interacts with its host environment. Most mathematical modeling of malignant tumor growth has assumed a homogeneous host environment. We have developed a cellular automaton model for tumor growth that explicitly incorporates the structural heterogeneity of the host environment such as tumor stroma. We show that these structural heterogeneities have non-trivial effects on the tumor growth dynamics and prognosis. Y. J. is supported by PSOC, NCI.

  16. A Tractable Approach to Coverage and Rate in Cellular Networks

    OpenAIRE

    Andrews, Jeffrey G.; Baccelli, Francois; Ganti, Radha Krishna

    2010-01-01

    Cellular networks are usually modeled by placing the base stations on a grid, with mobile users either randomly scattered or placed deterministically. These models have been used extensively but suffer from being both highly idealized and not very tractable, so complex system-level simulations are used to evaluate coverage/outage probability and rate. More tractable models have long been desirable. We develop new general models for the multi-cell signal-to-interference-plus-noise ratio (SINR)...

  17. Cellular Automaton Model for Immunology of Tumor Growth

    CERN Document Server

    Voitikova, M

    1998-01-01

    The stochastic discrete space-time model of an immune response on tumor spreading in a two-dimensional square lattice has been developed. The immunity-tumor interactions are described at the cellular level and then transferred into the setting of cellular automata (CA). The multistate CA model for system, in which all statesoflattice sites, composing of both immune and tumor cells populations, are the functions of the states of the 12 nearest neighbors. The CA model incorporates the essential featuresof the immunity-tumor system. Three regimes of neoplastic evolution including metastatic tumor growth and screen effect by inactive immune cells surrounding a tumor have been predicted.

  18. Cellular Growth Arrest and Persistence from Enzyme Saturation

    Science.gov (United States)

    Ray, J. Christian J.; Wickersheim, Michelle L.; Jalihal, Ameya P.; Adeshina, Yusuf O.; Cooper, Tim F.; Balázsi, Gábor

    2016-01-01

    Metabolic efficiency depends on the balance between supply and demand of metabolites, which is sensitive to environmental and physiological fluctuations, or noise, causing shortages or surpluses in the metabolic pipeline. How cells can reliably optimize biomass production in the presence of metabolic fluctuations is a fundamental question that has not been fully answered. Here we use mathematical models to predict that enzyme saturation creates distinct regimes of cellular growth, including a phase of growth arrest resulting from toxicity of the metabolic process. Noise can drive entry of single cells into growth arrest while a fast-growing majority sustains the population. We confirmed these predictions by measuring the growth dynamics of Escherichia coli utilizing lactose as a sole carbon source. The predicted heterogeneous growth emerged at high lactose concentrations, and was associated with cell death and production of antibiotic-tolerant persister cells. These results suggest how metabolic networks may balance costs and benefits, with important implications for drug tolerance. PMID:27010473

  19. Metal loss growth rate distributions

    Energy Technology Data Exchange (ETDEWEB)

    Nicoletti, Erika S.M.; Olivier, Joao H.; Souza, Ricardo D. de; Addor, Pedro N. [PETROBRAS Transporte S.A. (TRANSPETRO), Rio de Janeiro, RJ (Brazil)

    2009-12-19

    Significant efforts have been dedicated in recent decades to the development of damage tolerance criteria and ILI tool technology and, by combining both, operators can nowadays determine their system's integrity condition at the time of inspection with considerable accuracy. However, to accomplish proper integrity management it is also necessary to estimate the damage progression over time. As corrosion is one of the most time-dependent threats to pipeline integrity, aging systems' operational reliability and cost-effectiveness mostly rely on the accuracy of their corrosion growth-rate estimations. The diversity of mechanisms acting concomitantly along a single pipeline, and the inherent stochastic nature of the corrosion process makes its mechanistic modeling a complex task. This paper introduces the use of exploratory statistical analysis combined with segmentation strategies to produce representative corrosion rates of metal-loss anomaly populations reported by ILI. The procedure could provide input suitable for both deterministic and probabilistic FFP analysis: for the latter, proper computational tools to process best fitting distributions being required. Three case studies, where diverse segmentation principles have been applied, are presented to illustrate methodology application. (author)

  20. Methods of modelling relative growth rate

    Institute of Scientific and Technical Information of China (English)

    Arne Pommerening; Anders Muszta

    2015-01-01

    Background:Analysing and modelling plant growth is an important interdisciplinary field of plant science. The use of relative growth rates, involving the analysis of plant growth relative to plant size, has more or less independently emerged in different research groups and at different times and has provided powerful tools for assessing the growth performance and growth efficiency of plants and plant populations. In this paper, we explore how these isolated methods can be combined to form a consistent methodology for modelling relative growth rates. Methods:We review and combine existing methods of analysing and modelling relative growth rates and apply a combination of methods to Sitka spruce (Picea sitchensis (Bong.) Carr.) stem-analysis data from North Wales (UK) and British Douglas fir (Pseudotsuga menziesi (Mirb.) Franco) yield table data. Results:The results indicate that, by combining the approaches of different plant-growth analysis laboratories and using them simultaneously, we can advance and standardise the concept of relative plant growth. Particularly the growth multiplier plays an important role in modelling relative growth rates. Another useful technique has been the recent introduction of size-standardised relative growth rates. Conclusions:Modelling relative growth rates mainly serves two purposes, 1) an improved analysis of growth performance and efficiency and 2) the prediction of future or past growth rates. This makes the concept of relative growth ideally suited to growth reconstruction as required in dendrochronology, climate change and forest decline research and for interdisciplinary research projects beyond the realm of plant science.

  1. Rate Loss Due to Power Equalization in Cellular Communications

    OpenAIRE

    Rimoldi, Bixio; Duan, Long; Li, Quinn

    2001-01-01

    For a cellular communication network, the loss in up-link bandwidth-efficiency resulting from power equalization is considered. Here power equalization refers to the operation of adjusting the transmit power of mobile units in such a way that the received power is the same for all units whereas bandwidth-efficiency is measured in terms of sum-rate per cell divided by the total system bandwidth. A single-cell system is considered first, and the bandwidth efficiency is determined with and witho...

  2. Growth-rate-dependent dynamics of a bacterial genetic oscillator

    Science.gov (United States)

    Osella, Matteo; Lagomarsino, Marco Cosentino

    2013-01-01

    Gene networks exhibiting oscillatory dynamics are widespread in biology. The minimal regulatory designs giving rise to oscillations have been implemented synthetically and studied by mathematical modeling. However, most of the available analyses generally neglect the coupling of regulatory circuits with the cellular “chassis” in which the circuits are embedded. For example, the intracellular macromolecular composition of fast-growing bacteria changes with growth rate. As a consequence, important parameters of gene expression, such as ribosome concentration or cell volume, are growth-rate dependent, ultimately coupling the dynamics of genetic circuits with cell physiology. This work addresses the effects of growth rate on the dynamics of a paradigmatic example of genetic oscillator, the repressilator. Making use of empirical growth-rate dependencies of parameters in bacteria, we show that the repressilator dynamics can switch between oscillations and convergence to a fixed point depending on the cellular state of growth, and thus on the nutrients it is fed. The physical support of the circuit (type of plasmid or gene positions on the chromosome) also plays an important role in determining the oscillation stability and the growth-rate dependence of period and amplitude. This analysis has potential application in the field of synthetic biology, and suggests that the coupling between endogenous genetic oscillators and cell physiology can have substantial consequences for their functionality.

  3. Nanocrystallization kinetics under instantaneous growth approximation: Experiments and cellular automata simulations

    Energy Technology Data Exchange (ETDEWEB)

    Blazquez, J.S.; Millan, M.; Conde, C.F.; Conde, A. [Departamento de Fisica de la Materia Condensada, Universidad de Sevilla-ICMSE, P.O. Box 1065, 41080 Sevilla (Spain)

    2010-05-15

    Nanocrystallization kinetics is analyzed in the frame of instantaneous growth approximation, which implies that the time required for a crystallite to reach its final size is negligible with respect to the time required for the nanocrystallization process. This approach strongly simplifies the kinetic analysis and allows us to obtain the nucleation rate from both isothermal and non-isothermal nanocrystallization processes. Moreover, as no constraining mechanism is considered but the absence of growth, the results could be discussed in the frame of Johnson-Mehl-Avrami-Kolmogorov theory with a growth index equal to zero. Cellular automata simulations are in agreement with the observed kinetics and microstructure. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  4. Combining cellular automata and Monte Carlo algorithm to simulate three-dimensional grain growth

    Institute of Scientific and Technical Information of China (English)

    WANG Wei; CHEN Ju-hua; GUO Pei-quan; ZHAO Ping

    2006-01-01

    A 3-D simulation of grain growth was conducted by utilizing cellular automata (CA) and Monte Carlo (MC) algorithm. In the simulating procedure, the three-dimensional space is divided into a large number of 2-D isometric planes. Then, each of the planes is divided into identical square cells. Finally, the cellular automata and Monte Carlo algorithm are combined together to simulate the grain growth. Through an evolutionary simulation, the recrystallized microstructure, the grain growth rate and the grain size distribution are acceptably predicted. The simulation routine can be used to simulate the real physical-metallurgy processes and to predict quantitative dynamic information of the evolution of microstructure. Further more, the method is also useful for optimization of materials properties by controlling the microstructure evolution.

  5. Methods of modelling relative growth rate

    OpenAIRE

    Arne Pommerening; Anders Muszta

    2015-01-01

    Background Analysing and modelling plant growth is an important interdisciplinary field of plant science. The use of relative growth rates, involving the analysis of plant growth relative to plant size, has more or less independently emerged in different research groups and at different times and has provided powerful tools for assessing the growth performance and growth efficiency of plants and plant populations. In this paper, we explore how these isolated methods can be combined to form...

  6. Measurements of Protein Crystal Face Growth Rates

    Science.gov (United States)

    Gorti, S.

    2014-01-01

    Protein crystal growth rates will be determined for several hyperthermophile proteins.; The growth rates will be assessed using available theoretical models, including kinetic roughening.; If/when kinetic roughening supersaturations are established, determinations of protein crystal quality over a range of supersaturations will also be assessed.; The results of our ground based effort may well address the existence of a correlation between fundamental growth mechanisms and protein crystal quality.

  7. Growth Rates of Microbes in the Oceans

    Science.gov (United States)

    Kirchman, David L.

    2016-01-01

    A microbe's growth rate helps to set its ecological success and its contribution to food web dynamics and biogeochemical processes. Growth rates at the community level are constrained by biomass and trophic interactions among bacteria, phytoplankton, and their grazers. Phytoplankton growth rates are approximately 1 d-1, whereas most heterotrophic bacteria grow slowly, close to 0.1 d-1; only a few taxa can grow ten times as fast. Data from 16S rRNA and other approaches are used to speculate about the growth rate and the life history strategy of SAR11, the most abundant clade of heterotrophic bacteria in the oceans. These strategies are also explored using genomic data. Although the methods and data are imperfect, the available data can be used to set limits on growth rates and thus on the timescale for changes in the composition and structure of microbial communities.

  8. Export growth, economic growth and real exchange rate in Indonesia

    OpenAIRE

    Wing-Keung Lo, K.

    2000-01-01

    The thesis studies the export growth, economic growth and real exchange rate in Indonesia. The research is a piece of empirical studies mainly covering the period from 1974 to 1993. Indonesia is an oil-exporting country. Economic recession with high inflation rate in the early eighties prompted the government to undertake a series of economic and financial reforms. It was believed that oil export earnings by itself could not sustain long-term economic growth. Trade reform and devaluation woul...

  9. Role of Rate of Specific Growth Rate in Different Growth Processes: A First Principle Approach

    CERN Document Server

    Biswas, Dibyendu; Patra, Sankar Nayaran

    2015-01-01

    In the present communication, effort is given for the development of a common platform that helps to address several growth processes found in literature. Based on first principle approach, the role of rate of specific growth rate in different growth processes has been considered in an unified manner. It is found that different growth equations can be derived from the same rate equation of specific growth rate. The dependence of growth features of different growth processes on the parameters of the rate equation of specific growth rate has been examined in detail. It is found that competitive environment may increase the saturation level of population size. The exponential growth could also be addressed in terms of two important factors of growth dynamics, as reproduction and competition. These features are, most probably, not reported earlier.

  10. Noise in gene expression is coupled to growth rate

    OpenAIRE

    Keren, Leeat; van Dijk, David; Weingarten-Gabbay, Shira; Davidi, Dan; Jona, Ghil; Weinberger, Adina; Milo, Ron; Segal, Eran

    2015-01-01

    Genetically identical cells exposed to the same environment display variability in gene expression (noise), with important consequences for the fidelity of cellular regulation and biological function. Although population average gene expression is tightly coupled to growth rate, the effects of changes in environmental conditions on expression variability are not known. Here, we measure the single-cell expression distributions of approximately 900 Saccharomyces cerevisiae promoters across four...

  11. Temperature influence on phytoplankton community growth rates

    Science.gov (United States)

    Sherman, Elliot; Moore, J. Keith; Primeau, Francois; Tanouye, David

    2016-04-01

    A large database of field estimates of phytoplankton community growth rates in natural populations was compiled and analyzed to determine the apparent temperature effect on phytoplankton community growth rate. We conducted an ordinary least squares regression to optimize the parameters in two commonly used growth-temperature relations (Arrhenius and Q10 models). Both equations fit the observational data equally with the optimized parameter values. The optimum apparent Q10 value was 1.47 ± 0.08 (95% confidence interval, CI). Microzooplankton grazing rates closely matched the temperature trends for phytoplankton growth. This likely reflects a dynamic adjustment of biomass and grazing rates by the microzooplankton to match their available food source, illustrating tight coupling of phytoplankton growth and microzooplankton grazing rates. The field-measured temperature effect and growth rates were compared with estimates from the satellite Carbon-based Productivity Model (CbPM) and three Earth System Models (ESMs), with model output extracted at the same month and sampling locations as the observations. The optimized, apparent Q10 value calculated for the CbPM was 1.51, with overestimation of growth rates. The apparent Q10 value in the Community Earth System Model (V1.0) was 1.65, with modest underestimation of growth rates. The GFDL-ESM2M and GFDL-ESM2G models produced apparent Q10 values of 1.52 and 1.39, respectively. Models with an apparent Q10 that is significantly greater than ~1.5 will overestimate the phytoplankton community growth response to the ongoing climate warming and will have spatial biases in estimated growth rates for the current era.

  12. Stability Analysis of a Hybrid Cellular Automaton Model of Cell Colony Growth

    CERN Document Server

    Gerlee, P

    2007-01-01

    Cell colonies of bacteria, tumour cells and fungi, under nutrient limited growth conditions, exhibit complex branched growth patterns. In order to investigate this phenomenon we present a simple hybrid cellular automaton model of cell colony growth. In the model the growth of the colony is limited by a nutrient that is consumed by the cells and which inhibits cell division if it falls below a certain threshold. Using this model we have investigated how the nutrient consumption rate of the cells affects the growth dynamics of the colony. We found that for low consumption rates the colony takes on a Eden-like morphology, while for higher consumption rates the morphology of the colony is branched with a fractal geometry. These findings are in agreement with previous results, but the simplicity of the model presented here allows for a linear stability analysis of the system. By observing that the local growth of the colony is proportional to the flux of the nutrient we derive an approximate dispersion relation fo...

  13. Modeling of aluminum-silicon irregular eutectic growth by cellular automaton model

    Directory of Open Access Journals (Sweden)

    Rui Chen

    2016-03-01

    Full Text Available Due to the extensive application of Al-Si alloys in the automotive and aerospace industries as structural components, an understanding of their microstructural formation, such as dendrite and (Al+Si eutectic, is of great importance to control the desirable microstructure, so as to modify the performance of castings. Since previous major themes of microstructural simulation are dendrite and regular eutectic growth, few efforts have been paid to simulate the irregular eutectic growth. Therefore, a multiphase cellular automaton (CA model is developed and applied to simulate the time-dependent Al-Si irregular eutectic growth. Prior to model establishment, related experiments were carried out to investigate the influence of cooling rate and Sr modification on the growth of eutectic Si. This CA model incorporates several aspects, including growth algorithms and nucleation criterion, to achieve the competitive and cooperative growth mechanism for nonfaceted-faceted Al-Si irregular eutectic. The growth kinetics considers thermal undercooling, constitutional undercooling, and curvature undercooling, as well as the anisotropic characteristic of eutectic Si growth. The capturing rule takes into account the effects of modification on the silicon growth behaviors. The simulated results indicate that for unmodified alloy, the higher eutectic undercooling results in the higher eutectic growth velocity, and a more refined eutectic microstructure as well as narrower eutectic lamellar spacing. For modified alloy, the eutectic silicon tends to be obvious fibrous morphology and the morphology of eutectic Si is determined by both chemical modifier and cooling rate. The predicted microstructure of Al-7Si alloy under different solidification conditions shows that this proposed model can successfully reproduce both dendrite and eutectic microstructures.

  14. Large centric diatoms allocate more cellular nitrogen to photosynthesis to counter slower RUBISCO turnover rates

    Directory of Open Access Journals (Sweden)

    Yaping eWu

    2014-12-01

    Full Text Available Diatoms contribute ~40% of primary production in the modern ocean and encompass the largest cell size range of any phytoplankton group. Diatom cell size influences their nutrient uptake, photosynthetic light capture, carbon export efficiency, and growth responses to increasing pCO2. We therefore examined nitrogen resource allocations to the key protein complexes mediating photosynthesis across six marine centric diatoms, spanning 5 orders of magnitude in cell volume, under past, current and predicted future pCO2 levels, in balanced growth under nitrogen repletion. Membrane bound photosynthetic protein concentrations declined with cell volume in parallel with cellular concentrations of total protein, total nitrogen and chlorophyll. Larger diatom species, however, allocated a greater fraction (by 3.5 fold of their total cellular nitrogen to the soluble RUBISCO carbon fixation complex than did smaller species. Carbon assimilation per unit of RUBISCO large subunit (C RbcL-1 s-1 decreased with cell volume, from ~8 to ~2 C RbcL-1 s-1 from the smallest to the largest cells. Whilst a higher allocation of cellular nitrogen to RUBISCO in larger cells increases the burden upon their nitrogen metabolism, the higher RUBISCO allocation buffers their lower achieved RUBISCO turnover rate to enable larger diatoms to maintain carbon assimilation rates per total protein comparable to small diatoms. Individual species responded to increased pCO2, but cell size effects outweigh pCO2 responses across the diatom species size range examined. In large diatoms a higher nitrogen cost for RUBISCO exacerbates the higher nitrogen requirements associated with light absorption, so the metabolic cost to maintain photosynthesis is a cell size-dependent trait.

  15. Noise in gene expression is coupled to growth rate.

    Science.gov (United States)

    Keren, Leeat; van Dijk, David; Weingarten-Gabbay, Shira; Davidi, Dan; Jona, Ghil; Weinberger, Adina; Milo, Ron; Segal, Eran

    2015-12-01

    Genetically identical cells exposed to the same environment display variability in gene expression (noise), with important consequences for the fidelity of cellular regulation and biological function. Although population average gene expression is tightly coupled to growth rate, the effects of changes in environmental conditions on expression variability are not known. Here, we measure the single-cell expression distributions of approximately 900 Saccharomyces cerevisiae promoters across four environmental conditions using flow cytometry, and find that gene expression noise is tightly coupled to the environment and is generally higher at lower growth rates. Nutrient-poor conditions, which support lower growth rates, display elevated levels of noise for most promoters, regardless of their specific expression values. We present a simple model of noise in expression that results from having an asynchronous population, with cells at different cell-cycle stages, and with different partitioning of the cells between the stages at different growth rates. This model predicts non-monotonic global changes in noise at different growth rates as well as overall higher variability in expression for cell-cycle-regulated genes in all conditions. The consistency between this model and our data, as well as with noise measurements of cells growing in a chemostat at well-defined growth rates, suggests that cell-cycle heterogeneity is a major contributor to gene expression noise. Finally, we identify gene and promoter features that play a role in gene expression noise across conditions. Our results show the existence of growth-related global changes in gene expression noise and suggest their potential phenotypic implications. PMID:26355006

  16. EVIDENCE ON EMPLOYMENT RATE AND ECONOMIC GROWTH

    Directory of Open Access Journals (Sweden)

    Cornelia VĂCEANU

    2014-11-01

    Full Text Available This paper explores a causal relationship between employment rate and economic growth for European Union countries, in general, and produces a structural assessment of employment on the background of labour market dynamics. Economic growth is the key in economic theory and the main source of well-being and quality of life. Since the 2008 financial crisis, most European countries have experienced job shortage and unemployment problem, but today's European economic outlook is strengthening on the bases of a GDP growing momentum. Empirical data shows, regardless the GDP's moderate positive trend, the employment rate did not increase enough. Given this, the present analysis address the question: to what extent the employment rate is affected by economic growth?

  17. Modeling Tetragonal Lysozyme Crystal Growth Rates

    Science.gov (United States)

    Gorti, Sridhar; Forsythe, Elizabeth L.; Pusey, Marc L.

    2003-01-01

    Tetragonal lysozyme 110 face crystal growth rates, measured over 5 orders of magnitude in range, can be described using a model where growth occurs by 2D nucleation on the crystal surface for solution supersaturations of c/c(sub eq) less than or equal to 7 +/- 2. Based upon the model, the step energy per unit length, beta was estimated to be approx. 5.3 +/- 0.4 x 10(exp -7) erg/mol-cm, which for a step height of 56 A corresponds to barrier of approx. 7 +/- 1 k(sub B)T at 300 K. For supersaturations of c/c(sub eq) > 8, the model emphasizing crystal growth by 2D nucleation not only could not predict, but also consistently overestimated, the highest observable crystal growth rates. Kinetic roughening is hypothesized to occur at a cross-over supersaturation of c/c(sub eq) > 8, where crystal growth is postulated to occur by a different process such as adsorption. Under this assumption, all growth rate data indicated that a kinetic roughening transition and subsequent crystal growth by adsorption for all solution conditions, varying in buffer pH, temperature and precipitant concentration, occurs for c/c(sub eq)(T, pH, NaCl) in the range between 5 and 10, with an energy barrier for adsorption estimated to be approx. 20 k(sub B)T at 300 K. Based upon these and other estimates, we determined the size of the critical surface nucleate, at the crossover supersaturation and higher concentrations, to range from 4 to 10 molecules.

  18. A Minimalistic Resource Allocation Model to Explain Ubiquitous Increase in Protein Expression with Growth Rate.

    Science.gov (United States)

    Barenholz, Uri; Keren, Leeat; Segal, Eran; Milo, Ron

    2016-01-01

    Most proteins show changes in level across growth conditions. Many of these changes seem to be coordinated with the specific growth rate rather than the growth environment or the protein function. Although cellular growth rates, gene expression levels and gene regulation have been at the center of biological research for decades, there are only a few models giving a base line prediction of the dependence of the proteome fraction occupied by a gene with the specific growth rate. We present a simple model that predicts a widely coordinated increase in the fraction of many proteins out of the proteome, proportionally with the growth rate. The model reveals how passive redistribution of resources, due to active regulation of only a few proteins, can have proteome wide effects that are quantitatively predictable. Our model provides a potential explanation for why and how such a coordinated response of a large fraction of the proteome to the specific growth rate arises under different environmental conditions. The simplicity of our model can also be useful by serving as a baseline null hypothesis in the search for active regulation. We exemplify the usage of the model by analyzing the relationship between growth rate and proteome composition for the model microorganism E.coli as reflected in recent proteomics data sets spanning various growth conditions. We find that the fraction out of the proteome of a large number of proteins, and from different cellular processes, increases proportionally with the growth rate. Notably, ribosomal proteins, which have been previously reported to increase in fraction with growth rate, are only a small part of this group of proteins. We suggest that, although the fractions of many proteins change with the growth rate, such changes may be partially driven by a global effect, not necessarily requiring specific cellular control mechanisms. PMID:27073913

  19. Alveologenesis: key cellular players and fibroblast growth factor 10 signaling

    OpenAIRE

    Chao, Cho-Ming; Moiseenko, Alena; Zimmer, Klaus-Peter; Bellusci, Saverio

    2016-01-01

    Background Alveologenesis is the last stage in lung development and is essential for building the gas-exchanging units called alveoli. Despite intensive lung research, the intricate crosstalk between mesenchymal and epithelial cell lineages during alveologenesis is poorly understood. This crosstalk contributes to the formation of the secondary septae, which are key structures of healthy alveoli. Conclusions A better understanding of the cellular and molecular processes underlying the formatio...

  20. Transcription factor control of growth rate dependent genes in Saccharomyces cerevisiae: A three factor design

    DEFF Research Database (Denmark)

    Fazio, Alessandro; Jewett, Michael Christopher; Daran-Lapujade, Pascale;

    2008-01-01

    Background: Characterization of cellular growth is central to understanding living systems. Here, we applied a three-factor design to study the relationship between specific growth rate and genome-wide gene expression in 36 steady-state chemostat cultures of Saccharomyces cerevisiae. The three...... factors we considered were specific growth rate, nutrient limitation, and oxygen availability. Results: We identified 268 growth rate dependent genes, independent of nutrient limitation and oxygen availability. The transcriptional response was used to identify key areas in metabolism around which m...

  1. In situ investigation of growth rates and growth rate dispersion of α-lactose monohydrate crystals

    Science.gov (United States)

    Dincer, T. D.; Ogden, M. I.; Parkinson, G. M.

    2009-02-01

    The growth rates and growth rate dispersion (GRD) of four different faces of α-lactose monohydrate crystal were measured at 30, 40 and 50 °C in the relative supersaturation range 0.55-2.33 in aqueous solutions. The overall growth rate of the crystal is around 50-60% of the (0 1 0) face of the crystal. The power law was applied to the growth rates of the four faces and the activation energies were calculated to be between 9.5 and 13.7 kcal/mol. This indicates a diffusion-controlled growth, but the exponents calculated are between 2.5 and 3.1 which are higher than unity. Introduction of critical supersaturation decreased the exponents to between 1.8 and 2.4. The variance of GRD for the (0 1 0) face is twice the variance of the GRD of the (1 1 0) and (1 0 0) faces and 10 times higher than the (1 1¯ 1¯) face at the same supersaturations and temperatures. The GRD of the four faces were similar when expressed as a function of growth rate. However, the (0 1 1) face displayed lower GRD than the other faces at the same temperatures and supersaturations.

  2. Cellular Metabolic Rate Is Influenced by Life-History Traits in Tropical and Temperate Birds

    OpenAIRE

    Jimenez, Ana Gabriela; Van Brocklyn, James; Wortman, Matthew; Williams, Joseph B.

    2014-01-01

    In general, tropical birds have a “slow pace of life,” lower rates of whole-animal metabolism and higher survival rates, than temperate species. A fundamental challenge facing physiological ecologists is the understanding of how variation in life-history at the whole-organism level might be linked to cellular function. Because tropical birds have lower rates of whole-animal metabolism, we hypothesized that cells from tropical species would also have lower rates of cellular metabolism than cel...

  3. Species Diversity Enhances Predator Growth Rates

    Directory of Open Access Journals (Sweden)

    Mark H. Olson

    2007-01-01

    Full Text Available Predators can be important top-down regulators of community structure and are known to have both positive and negative effects on species diversity. However, little is known about the reciprocal effects of species diversity on predators. Across a set of 80 lakes in Connecticut, USA, we found a strong positive correlation between prey species diversity (using the Shannon-Weiner Diversity Index and growth rates of largemouth bass (Micropterus salmoides. This correlation was strongest for small predators and decreased with body size. Although the underlying mechanisms are not known, the correlation is not driven by total fish abundance, predator abundance, or productivity.

  4. Hexachlorobenzene induces deregulation of cellular growth in rat liver

    International Nuclear Information System (INIS)

    Hexachlorobenzene (HCB) is an organochlorine pesticide widely distributed in the biosphere. The aim of the present study was to investigate the effect of HCB on the homeostasis of liver cell growth, analyzing parameters of cell proliferation and apoptosis, in HCB (0.1, 1, 10 and 100 mg/kg body weight)-treated rats, during 4 weeks. Cell proliferation and ERK1/2 phosphorylation, associated with survival mechanisms, were increased at HCB 100 mg/kg. The pesticide increased the number of apoptotic cells, and the activation of caspase-3, -9 and -8, in a dose-dependent manner, suggesting that HCB-induced apoptosis is mediated by caspases. Increased Fas and FasL protein levels indicate that the death receptor pathway is also involved. This process is associated with decreased Bid, and increased cytosolic cytochrome c protein levels. Transforming growth factor-beta1 (TGF-β1) intervenes in apoptotic and/or proliferative processes in hepatocytes. TGF-β1 cDNA and protein levels are dose-dependently increased, suggesting that this cytokine might be involved in HCB-induced dysregulation of cell proliferation and apoptosis. In conclusion, this study reports for the first time that HCB induces loss of the homeostatic balance between cell growth and cell death in rat liver. Induced apoptosis occurs by mechanisms involving signals emanating from death receptors, and the mitochondrial pathway.

  5. On Modeling Coverage and Rate of Random Cellular Networks under Generic Channel Fading

    OpenAIRE

    Al-Hourani, Akram; Kandeepan, Sithamparanathan

    2016-01-01

    In this paper we provide an analytic framework for computing the expected downlink coverage probability, and the associated data rate of cellular networks, where base stations are distributed in a random manner. The provided expressions are in computable integral forms that accommodate generic channel fading conditions. We develop these expressions by modelling the cellular interference using stochastic geometry analysis, then we employ them for comparing the coverage resulting from various c...

  6. Matrix rigidity regulates cancer cell growth and cellular phenotype.

    Directory of Open Access Journals (Sweden)

    Robert W Tilghman

    Full Text Available BACKGROUND: The mechanical properties of the extracellular matrix have an important role in cell growth and differentiation. However, it is unclear as to what extent cancer cells respond to changes in the mechanical properties (rigidity/stiffness of the microenvironment and how this response varies among cancer cell lines. METHODOLOGY/PRINCIPAL FINDINGS: In this study we used a recently developed 96-well plate system that arrays extracellular matrix-conjugated polyacrylamide gels that increase in stiffness by at least 50-fold across the plate. This plate was used to determine how changes in the rigidity of the extracellular matrix modulate the biological properties of tumor cells. The cell lines tested fall into one of two categories based on their proliferation on substrates of differing stiffness: "rigidity dependent" (those which show an increase in cell growth as extracellular rigidity is increased, and "rigidity independent" (those which grow equally on both soft and stiff substrates. Cells which grew poorly on soft gels also showed decreased spreading and migration under these conditions. More importantly, seeding the cell lines into the lungs of nude mice revealed that the ability of cells to grow on soft gels in vitro correlated with their ability to grow in a soft tissue environment in vivo. The lung carcinoma line A549 responded to culture on soft gels by expressing the differentiated epithelial marker E-cadherin and decreasing the expression of the mesenchymal transcription factor Slug. CONCLUSIONS/SIGNIFICANCE: These observations suggest that the mechanical properties of the matrix environment play a significant role in regulating the proliferation and the morphological properties of cancer cells. Further, the multiwell format of the soft-plate assay is a useful and effective adjunct to established 3-dimensional cell culture models.

  7. Cellular Adhesion Tripeptide RGD Inhibits Growth of Human Ileocecal Adenocarcinoma Cells HCT-8 and Induces Apoptosis

    Institute of Scientific and Technical Information of China (English)

    WANG Hua; ZENG Hong-bin; YANG Shao-juan; GAO Shen; HUANG Yi-bing; HOU Rui-zhen; ZHAO Mi-feng; XU Li; ZHANG Xue-zhong

    2007-01-01

    The tripeptide, Arg-Gly-Asp(RGD) motif is an integrin-recognition site found in adhesive proteins present in extracellular matrices(ECM) and in the blood. HCT-8 cells were treated with cellular adhesion tripeptide RGD at various concentrations. MTT assay was performed to examine the growth and proliferation of HCT-8 cells after treatment with RGD for 48 h. Haematoxylin and Eosin(HE) staining and electromicroscope were used to observe the morphology of apoptotic cells. Survivin and flow cytometry were also used to analyze the HCT-8 apoptosis. Cellular adhesion tripeptide RGD significantly inhibits the growth and proliferation of HCT-8 cells in a dose-dependent manner and induces apoptosis of HCT-8. These results indicate that cellular adhesion tripeptide RGD inhibits the growth and proliferation of tumor HCT-8 cell, probably by the aid of inducing apoptosis of HCT-8 cell.

  8. Spatiotemporal Simulation of Tourist Town Growth Based on the Cellular Automata Model: The Case of Sanpo Town in Hebei Province

    Directory of Open Access Journals (Sweden)

    Jun Yang

    2013-01-01

    Full Text Available Spatiotemporal simulation of tourist town growth is important for research on land use/cover change under the influence of urbanization. Many scholars have shown great interest in the unique pattern of driving urban development with tourism development. Based on the cellular automata (CA model, we simulated and predicted the spatiotemporal growth of Sanpo town in Hebei Province, using the tourism urbanization growth model. Results showed that (1 average annual growth rate of the entire region was 1.5 Ha2 per year from 2005 to 2010, 4 Ha2 per year from 2010 to 2015, and 2.5 Ha2 per year from 2015 to 2020; (2 urban growth rate increased yearly, with regional differences, and had a high degree of correlation with the Euclidean distance of town center, traffic route, attractions, and other factors; (3 Gougezhuang, an important village center in the west of the town, demonstrated traffic advantages and increased growth rate since 2010; (4 Magezhuang village has the largest population in the region, so economic advantages have driven the development of rural urbanization. It showed that CA had high reliability in simulating the spatiotemporal evolution of tourist town, which assists the study of spatiotemporal growth under urbanization and rational protection of tourism resources.

  9. Zero-Outage Cellular Downlink with Fixed-Rate D2D Underlay

    DEFF Research Database (Denmark)

    Kiilerich Pratas, Nuno; Popovski, Petar

    2015-01-01

    Two of the emerging trends in wireless cellular systems are Device-to-Device (D2D) and Machine-to-Machine (M2M) communications. D2D enables efficient reuse of the licensed spectrum to support localized transmissions, while M2M connections are often characterized by fixed and low transmission rates....... D2D connections can be instrumental in localized aggregation of uplink M2M traffic to a more capable cellular device, before being finally delivered to the Base Station (BS). In this paper we show that a fixed M2M rate is an enabler of efficient Machine-Type D2D underlay operation taking place...

  10. Quorum Sensing Influences Vibrio harveyi Growth Rates in a Manner Not Fully Accounted For by the Marker Effect of Bioluminescence

    OpenAIRE

    Zeena E Nackerdien; Keynan, Alexander; Bassler, Bonnie L.; Lederberg, Joshua; Thaler, David S

    2008-01-01

    Background The light-emitting Vibrios provide excellent material for studying the interaction of cellular communication with growth rate because bioluminescence is a convenient marker for quorum sensing. However, the use of bioluminescence as a marker is complicated because bioluminescence itself may affect growth rate, e.g. by diverting energy. Methodology/Principal Findings The marker effect was explored via growth rate studies in isogenic Vibrio harveyi (Vh) strains altered in quorum sensi...

  11. Quorum Sensing Influences Vibrio harveyi Growth Rates in a Manner Not Fully Accounted For by the Marker Effect of Bioluminescence

    OpenAIRE

    Zeena E Nackerdien; Alexander Keynan; Bassler, Bonnie L.; Joshua Lederberg; Thaler, David S

    2008-01-01

    BACKGROUND: The light-emitting Vibrios provide excellent material for studying the interaction of cellular communication with growth rate because bioluminescence is a convenient marker for quorum sensing. However, the use of bioluminescence as a marker is complicated because bioluminescence itself may affect growth rate, e.g. by diverting energy. METHODOLOGY/PRINCIPAL FINDINGS: The marker effect was explored via growth rate studies in isogenic Vibrio harveyi (Vh) strains altered in quorum sen...

  12. Cellular metabolic rate is influenced by life-history traits in tropical and temperate birds.

    Directory of Open Access Journals (Sweden)

    Ana Gabriela Jimenez

    Full Text Available In general, tropical birds have a "slow pace of life," lower rates of whole-animal metabolism and higher survival rates, than temperate species. A fundamental challenge facing physiological ecologists is the understanding of how variation in life-history at the whole-organism level might be linked to cellular function. Because tropical birds have lower rates of whole-animal metabolism, we hypothesized that cells from tropical species would also have lower rates of cellular metabolism than cells from temperate species of similar body size and common phylogenetic history. We cultured primary dermal fibroblasts from 17 tropical and 17 temperate phylogenetically-paired species of birds in a common nutritive and thermal environment and then examined basal, uncoupled, and non-mitochondrial cellular O2 consumption (OCR, proton leak, and anaerobic glycolysis (extracellular acidification rates [ECAR], using an XF24 Seahorse Analyzer. We found that multiple measures of metabolism in cells from tropical birds were significantly lower than their temperate counterparts. Basal and uncoupled cellular metabolism were 29% and 35% lower in cells from tropical birds, respectively, a decrease closely aligned with differences in whole-animal metabolism between tropical and temperate birds. Proton leak was significantly lower in cells from tropical birds compared with cells from temperate birds. Our results offer compelling evidence that whole-animal metabolism is linked to cellular respiration as a function of an animal's life-history evolution. These findings are consistent with the idea that natural selection has uniquely fashioned cells of long-lived tropical bird species to have lower rates of metabolism than cells from shorter-lived temperate species.

  13. The influence of the cellular phone radiation on the growth of mark145 cell

    International Nuclear Information System (INIS)

    Objective: To explore the effects of radiation of cellular phone on the growth of cells. Methods: A radiation cycle was designed as working 25 minutes and then resting for 5 minutes for cellular phone. The Mark145 cell bottles were divided into six groups. The first two groups were radiated for two cycles, and the second two groups for four cycles, and the third two groups for five cycles. Each two groups were put 10cm far away from cellular phone and attach to it separately. Results: After culturing for 3 days there are many dead cells in the bottles. After culturing for 6 days, there is few living cells. Conclusions: cellular phone radiation is fatal to Mark145 cells, and the quantity of the dead cells change with the radiation time and the distance to radiation. That is to say, with the prolonging of radiation time and the shortening of the distance, the quantity of the dead cells is increasing. (authors)

  14. Interactive effects of and light on growth rates and RUBISCO content of small and large centric diatoms

    Science.gov (United States)

    Li, G.; Campbell, D. A.

    2015-10-01

    Among marine phytoplankton groups, diatoms span the widest range of cell size, with resulting effects upon their nitrogen uptake, photosynthesis and growth responses to light. We grew two strains of marine centric diatoms, the small Thalassiosira pseudonana and the larger T. punctigera in high and low nitrogen media, across a range of growth light levels. Nitrogen and total proteins per cell decreased with increasing growth light in both species when grown under low nitrogen media. Surprisingly, low nitrogen increased the cellular allocation to RUBISCO and the rate of electron transport away from Photosystem II for the smaller diatom under low growth light, and for the larger diatom across the range of growth lights. Low nitrogen decreased the growth rate of the smaller diatom, particularly under higher light, but stimulated the growth rate of the larger diatom. Our results show that the high nitrogen in common growth media favours the growth rate of a small diatom but inhibits growth of a larger species.

  15. Growth against entropy in bacterial metabolism: the phenotypic trade-off behind empirical growth rate distributions in E. coli

    Science.gov (United States)

    De Martino, Daniele; Capuani, Fabrizio; De Martino, Andrea

    2016-06-01

    The solution space of genome-scale models of cellular metabolism provides a map between physically viable flux configurations and cellular metabolic phenotypes described, at the most basic level, by the corresponding growth rates. By sampling the solution space of E. coli's metabolic network, we show that empirical growth rate distributions recently obtained in experiments at single-cell resolution can be explained in terms of a trade-off between the higher fitness of fast-growing phenotypes and the higher entropy of slow-growing ones. Based on this, we propose a minimal model for the evolution of a large bacterial population that captures this trade-off. The scaling relationships observed in experiments encode, in such frameworks, for the same distance from the maximum achievable growth rate, the same degree of growth rate maximization, and/or the same rate of phenotypic change. Being grounded on genome-scale metabolic network reconstructions, these results allow for multiple implications and extensions in spite of the underlying conceptual simplicity.

  16. Calcite crystal growth rate inhibition by polycarboxylic acids

    Science.gov (United States)

    Reddy, M.M.; Hoch, A.R.

    2001-01-01

    Calcite crystal growth rates measured in the presence of several polycarboxyclic acids show that tetrahydrofurantetracarboxylic acid (THFTCA) and cyclopentanetetracarboxylic acid (CPTCA) are effective growth rate inhibitors at low solution concentrations (0.01 to 1 mg/L). In contrast, linear polycarbocylic acids (citric acid and tricarballylic acid) had no inhibiting effect on calcite growth rates at concentrations up to 10 mg/L. Calcite crystal growth rate inhibition by cyclic polycarboxyclic acids appears to involve blockage of crystal growth sites on the mineral surface by several carboxylate groups. Growth morphology varied for growth in the absence and in the presence of both THFTCA and CPTCA. More effective growth rate reduction by CPTCA relative to THFTCA suggests that inhibitor carboxylate stereochemical orientation controls calcite surface interaction with carboxylate inhibitors. ?? 20O1 Academic Press.

  17. Maximal sum of metabolic exchange fluxes outperforms biomass yield as a predictor of growth rate of microorganisms.

    Science.gov (United States)

    Zarecki, Raphy; Oberhardt, Matthew A; Yizhak, Keren; Wagner, Allon; Shtifman Segal, Ella; Freilich, Shiri; Henry, Christopher S; Gophna, Uri; Ruppin, Eytan

    2014-01-01

    Growth rate has long been considered one of the most valuable phenotypes that can be measured in cells. Aside from being highly accessible and informative in laboratory cultures, maximal growth rate is often a prime determinant of cellular fitness, and predicting phenotypes that underlie fitness is key to both understanding and manipulating life. Despite this, current methods for predicting microbial fitness typically focus on yields [e.g., predictions of biomass yield using GEnome-scale metabolic Models (GEMs)] or notably require many empirical kinetic constants or substrate uptake rates, which render these methods ineffective in cases where fitness derives most directly from growth rate. Here we present a new method for predicting cellular growth rate, termed SUMEX, which does not require any empirical variables apart from a metabolic network (i.e., a GEM) and the growth medium. SUMEX is calculated by maximizing the SUM of molar EXchange fluxes (hence SUMEX) in a genome-scale metabolic model. SUMEX successfully predicts relative microbial growth rates across species, environments, and genetic conditions, outperforming traditional cellular objectives (most notably, the convention assuming biomass maximization). The success of SUMEX suggests that the ability of a cell to catabolize substrates and produce a strong proton gradient enables fast cell growth. Easily applicable heuristics for predicting growth rate, such as what we demonstrate with SUMEX, may contribute to numerous medical and biotechnological goals, ranging from the engineering of faster-growing industrial strains, modeling of mixed ecological communities, and the inhibition of cancer growth. PMID:24866123

  18. Maximal sum of metabolic exchange fluxes outperforms biomass yield as a predictor of growth rate of microorganisms.

    Directory of Open Access Journals (Sweden)

    Raphy Zarecki

    Full Text Available Growth rate has long been considered one of the most valuable phenotypes that can be measured in cells. Aside from being highly accessible and informative in laboratory cultures, maximal growth rate is often a prime determinant of cellular fitness, and predicting phenotypes that underlie fitness is key to both understanding and manipulating life. Despite this, current methods for predicting microbial fitness typically focus on yields [e.g., predictions of biomass yield using GEnome-scale metabolic Models (GEMs] or notably require many empirical kinetic constants or substrate uptake rates, which render these methods ineffective in cases where fitness derives most directly from growth rate. Here we present a new method for predicting cellular growth rate, termed SUMEX, which does not require any empirical variables apart from a metabolic network (i.e., a GEM and the growth medium. SUMEX is calculated by maximizing the SUM of molar EXchange fluxes (hence SUMEX in a genome-scale metabolic model. SUMEX successfully predicts relative microbial growth rates across species, environments, and genetic conditions, outperforming traditional cellular objectives (most notably, the convention assuming biomass maximization. The success of SUMEX suggests that the ability of a cell to catabolize substrates and produce a strong proton gradient enables fast cell growth. Easily applicable heuristics for predicting growth rate, such as what we demonstrate with SUMEX, may contribute to numerous medical and biotechnological goals, ranging from the engineering of faster-growing industrial strains, modeling of mixed ecological communities, and the inhibition of cancer growth.

  19. Sweat secretion rates in growth hormone disorders

    DEFF Research Database (Denmark)

    Sneppen, S B; Main, K M; Juul, A;

    2000-01-01

    While increased sweating is a prominent symptom in patients with active acromegaly, reduced sweating is gaining status as part of the growth hormone deficiency (GHD) syndrome.......While increased sweating is a prominent symptom in patients with active acromegaly, reduced sweating is gaining status as part of the growth hormone deficiency (GHD) syndrome....

  20. A Simple Scheme for Improved Performance of Fixed Outage Rate Cellular System

    Directory of Open Access Journals (Sweden)

    Hussein M.A. Basi

    2004-01-01

    Full Text Available The traffic characteristic of mobile cellular systems is rather distinct from that of a fixed telephone network. However the system planning and design are still carried out with the tools of conventional traffic theory. In the recent days much work is being done in the performance evaluation of mobile or cellular communication systems in order to develop a system with greater efficiency. The useful parameters to estimate the performance of the system are voice quality, frequency spectrum efficiency and Grade of Service (GOS. The grade of service will be affected due to outage of channels. In this study, a new scheme is proposed to reduce lost calls due to channel outage in the fixed rate outage cellular system. In this proposed scheme the call will never dropped but may be delayed. The system performance is evaluated for different conditions and the results are discussed.

  1. Underlay of low-rate machine-type D2D links on downlink cellular links

    DEFF Research Database (Denmark)

    Pratas, Nuno K.; Popovski, Petar

    2014-01-01

    Wireless cellular networks feature two emerging technological trends: direct Device-to-Device (D2D) communications and Machine-Type Communications (MTC). MTC devices (MTDs) pose new challenges to the cellular network, such as low transmission power and massive access that can lead to overload of...... the radio interface. In this paper we explore the opportunity opened by D2D links for supporting Low-rate Low-power MTDs that are connected to a nearby device, such as an on-body MTD connected to a mobile phone that acts as a relay towards the Base Station (BS). The low-rate requirement for this D2D...... probability for the MTC link. The results show that SIC is an important enabler of low-power underlay D2D transmission for low-rate machine-type traffic; however, it may incur a significant rate penalty for the cellular users when trying to meet the outage requirements of the MTC link....

  2. Analysis of dose-rate effects on cellular responses to chronic radiation exposure

    International Nuclear Information System (INIS)

    The effects in the title were studied on their expression of various genes concerned with radiation exposure by the acute (1 Gy/min) and chronic (0.007-0.694 Gy/min) irradiations to various cell lines. Cell of human origin were the primarily cultured fibroblasts (F), their immortalized strain (imF) by transduction of human teromerase transcriptase (hTERT), breast cancer MCF-7, osteosarcoma U-20S, colon cancer HCT-116 and T-cell leukemia Jurkat. Acute irradiation was done in a gamma-cell with Cs-137 gamma-ray and chronic one, in a CO2-incubator with the Cs-137 source. Expression of genes was analyzed by mRNA sequence with Genome Analyzer. Proteins of p53, p53-Ser15-P, murine double minute 2 (MDM2), p21 and a/b-tubulin were analyzed by Western blotting. D0 values of acute irradiation were found in the range of 1.1-1.4 Gy, suggesting the similar sensitivity of used cells. However, responses to chronic exposure were different from cells to cells: particularly, at 0.347 mGy/min, no effect on growth was observed in cancer-derived cells until 10 days whereas a marked growth inhibition of F and imF cells was seen after 4 days. Arrest of proliferation of F cells after 10 days exposure at 0.347 mGy/min was tentative, but at 0.694 mGy/min, it was irreversible dependently on the exposure time. They were arrested at G0 stage. Gene expression analyzed by mRNA sequence was shown to be changed even by the lowest rate 0.007 mGy/min: levels of protein expressed under control of cancer-suppressing p53 were markedly altered. Western blotting showed an increased expression of examined proteins except for p53, at higher dose than 0.069 mGy/min. Results indicated that the cellular response to radiation involved not only DNA damage but also the process of yielding the damage. (T.T.)

  3. Growth rates and aggregate welfare : an international comparison

    OpenAIRE

    Kakwani, Nanak

    1991-01-01

    This paper explores the relationship between growth rates and changes in welfare, using alternative procedures for measuring growth. The Bank and other organizations often compute growth rates by fitting a least-squares linear trend line to the logarithmic values of economic indicators for a period. This paper questions the use of the least-squares procedure for measuring people's economic welfare over time. Instead, the author develops a conceptual framework for deriving an aggregate growth ...

  4. Growth rate determinations from radiocarbon in bamboo corals (genus Keratoisis)

    Science.gov (United States)

    Farmer, Jesse R.; Robinson, Laura F.; Hönisch, Bärbel

    2015-11-01

    Radiocarbon (14C) measurements are an important tool for determining growth rates of bamboo corals, a cosmopolitan group of calcitic deep-sea corals. Published growth rate estimates for bamboo corals are highly variable, with potential environmental or ecological drivers of this variability poorly constrained. Here we systematically investigate the application of 14C for growth rate determinations in bamboo corals using 55 14C dates on the calcite and organic fractions of six bamboo corals (identified as Keratoisis sp.) from the western North Atlantic Ocean. Calcite 14C measurements on the distal surface of these corals and five previously published bamboo corals exhibit a strong one-to-one relationship with the 14C of dissolved inorganic carbon (DI14C) in ambient seawater (r2=0.98), confirming the use of Keratoisis sp. calcite 14C as a proxy for seawater 14C activity. Radial growth rates determined from 14C age-depth regressions, 14C plateau tuning and bomb 14C reference chronologies range from 12 to 78 μm y-1, in general agreement with previously published radiometric growth rates. We document potential biases to 14C growth rate determinations resulting from water mass variability, bomb radiocarbon, secondary infilling (ontogeny), and growth rate nonlinearity. Radial growth rates for Keratoisis sp. specimens do not correlate with ambient temperature, suggesting that additional biological and/or environmental factors may influence bamboo coral growth rates.

  5. Uptake rate of cationic mitochondrial inhibitor MKT-077 determines cellular oxygen consumption change in carcinoma cells.

    Directory of Open Access Journals (Sweden)

    John L Chunta

    Full Text Available OBJECTIVE: Since tumor radiation response is oxygen-dependent, radiosensitivity can be enhanced by increasing tumor oxygenation. Theoretically, inhibiting cellular oxygen consumption is the most efficient way to increase oxygen levels. The cationic, rhodacyanine dye-analog MKT-077 inhibits mitochondrial respiration and could be an effective metabolic inhibitor. However, the relationship between cellular MKT-077 uptake and metabolic inhibition is unknown. We hypothesized that rat and human mammary carcinoma cells would take up MKT-077, causing a decrease in oxygen metabolism related to drug uptake. METHODS: R3230Ac rat breast adenocarcinoma cells were exposed to MKT-077. Cellular MKT-077 concentration was quantified using spectroscopy, and oxygen consumption was measured using polarographic electrodes. MKT-077 uptake kinetics were modeled by accounting for uptake due to both the concentration and potential gradients across the plasma and mitochondrial membranes. These kinetic parameters were used to model the relationship between MKT-077 uptake and metabolic inhibition. MKT-077-induced changes in oxygen consumption were also characterized in MDA-MB231 human breast carcinoma cells. RESULTS: Cells took up MKT-077 with a time constant of ∼1 hr, and modeling showed that over 90% of intracellular MKT-077 was bound or sequestered, likely by the mitochondria. The uptake resulted in a rapid decrease in oxygen consumption, with a time constant of ∼30 minutes. Surprisingly the change in oxygen consumption was proportional to uptake rate, not cellular concentration. MKT-077 proved a potent metabolic inhibitor, with dose-dependent decreases of 45-73% (p = 0.003. CONCLUSIONS: MKT-077 caused an uptake rate-dependent decrease in cellular metabolism, suggesting potential efficacy for increasing tumor oxygen levels and radiosensitivity in vivo.

  6. Phase and its morphologies of Ti-45 %Al alloy directionally solidified at different growth rates

    Institute of Scientific and Technical Information of China (English)

    LIU Chang; SU Yan-qing; BI Wei-sheng; GUO Jing-Jie; JIA Jun; FU Heng-zhi

    2005-01-01

    The microstructures of Ti-45%Al(molar fraction) alloy directionally solidified at different growth rates in alumina tube by electromagnetic heating zone melting were studied. The measured temperature gradient of the system is about 104K/m. The microstructures show that the primary solidified phase is β phase at different growth rates. The growth at low rates from 1.94 × 10-6 m/s to 4. 16 × 10-6 m/s results in a transient solid/liquid interface structure from planar to shallow cellular. This transient rate is larger than the theoretical value of vc = 6.94 × 10-7 m/s.Compared with vt = vc/k = 1.01 × 10-6 m/s, the cellular-dendritic transient rate of experiment is observed in the range of 1.67 × 10-5- 2.50 × 10-5 m/s. The primary arm spacing decreases with increasing growth rate.

  7. Phase transition in the economically modeled growth of a cellular nervous system

    OpenAIRE

    Nicosia V.; Vertes P.E.; Schafer W.R.; Latora V.; Bullmore E.T.

    2013-01-01

    Spatially embedded complex networks, such as nervous systems, the Internet, and transportation networks, generally have nontrivial topological patterns of connections combined with nearly minimal wiring costs. However, the growth rules shaping these economical tradeoffs between cost and topology are not well understood. Here, we study the cellular nervous system of the nematode worm Caenorhabditis elegans, together with information on the birth times of neurons and on their spatial locations....

  8. Impact of stretching-segment on saturated flow rate of signalized intersection using cellular automation

    Institute of Scientific and Technical Information of China (English)

    李岩; 陈宽民; 过秀成

    2013-01-01

    In order to analyze the impact of stretching-segment on the saturated flow rate of signalized intersection approach, an improved cellular automation model was proposed to estimate its saturated flow rate. The NaSch model was improved by adding different slow probabilities, turning deceleration rules and modified lane changing rules. The relationship between the saturated flow rate of stretching-segments and adjacent lanes was tested in numerical simulation. The length of stretching-segment, cycle length and green time were selected as impact factors of the cellular automation model. The simulation result indicates that the geometrics design of stretching-segment and the traffic signal timing scenario have major effects on the saturated flow rate of the intersection approach. The saturated flow rate will continually increase with increasing stretching-segment length until it reaches a threshold. After reaching the threshold, the stretching-segment can be treated as a separate lane. The green time is approximately linearly related to the threshold length of the stretching-segment. An optimum cycle length exists when the length of the stretching-segment is not long enough, and it is approximately linearly related to the length of stretching-segment.

  9. Bit-Vectorized GPU Implementation of a Stochastic Cellular Automaton Model for Surface Growth

    CERN Document Server

    Kelling, Jeffrey; Gemming, Sibylle

    2016-01-01

    Stochastic surface growth models aid in studying properties of universality classes like the Kardar--Paris--Zhang class. High precision results obtained from large scale computational studies can be transferred to many physical systems. Many properties, such as roughening and some two-time functions can be studied using stochastic cellular automaton (SCA) variants of stochastic models. Here we present a highly efficient SCA implementation of a surface growth model capable of simulating billions of lattice sites on a single GPU. We also provide insight into cases requiring arbitrary random probabilities which are not accessible through bit-vectorization.

  10. On the growth rate of the foliicolous lichen Strigula elegans

    NARCIS (Netherlands)

    Wilde-Duyfjes, de B.E.E.

    1967-01-01

    The diametral growth rate of the foliicolous lichen Strigula elegans (Fée) Müll. Arg., measured under natural conditions in the African tropical rainforest, has been established to amount to (0.7-)3-3-6(-8) mm annually. As compared to the diametral growth rate of lichens from temperate regions, whic

  11. An Economic Growth Model with Optimal Growth Rate and Individual Years of Schooling

    Directory of Open Access Journals (Sweden)

    Huan Yang

    2015-01-01

    Full Text Available An economic growth model with individual years of schooling is present. It is proved that there exist optimal individual years of schooling for fixed wage growth rate. On the other hand, the economy has balance growth path for given individual years of schooling. Finally, we prove that there exist optimal individual years of schooling and economic growth rate such that the individual lifetime utility reaches maximum and the economy grows on a balance growth path.

  12. On the Transformations between Temporal and Spatial Growth Rates.

    Science.gov (United States)

    Peng, Melinda S.; Williams, R. T.

    1987-09-01

    This note compares the error distributions for three transformation formulae between temporal growth rate and spatial growth rate with the linearized barotropic vorticity equation. The sech2 and the tanh basic-state profiles are used for illustration. The transformation which uses the phase velocity gives a moderate error which does not have a strong dependence on the growth rate. The formulae derived by Gaster, and later by Nayfeh and Padhye, which employ the group velocity, have errors that are a function of the ratio of the spatial growth rate to the wavenumber. The errors from their formulae are small when the ratio is small, but the errors increase with the ratio so that all three transformation formulae give similar errors when the ratio is of order one. Nayfeh and Padhye's formula is rederived for the barotropic vorticity equation with a procedure which shows that ratio of growth rate to wavenumber must be small for accuracy.

  13. Growth rates and feeding management of Irish thoroughbred foals

    OpenAIRE

    Griffin, Róisín

    2015-01-01

    peer-reviewed Limited studies have focused on the growth of Irish Thoroughbred (TB) foals. The objectives of this study were to track the growth of foals and to monitor growth rates based on nutritional intakes. The growth of 72 foals, on eight Irish stud farms were monitored monthly from birth to six months of age. Body weight (BW), average daily gain (ADG), wither height (WH), body length (BL), heart girth (HG) and cannon bone circumference (CC) were measured monthly. Representative samp...

  14. Dynamical Allocation of Cellular Resources as an Optimal Control Problem: Novel Insights into Microbial Growth Strategies

    Science.gov (United States)

    Giordano, Nils; Mairet, Francis; Gouzé, Jean-Luc

    2016-01-01

    Microbial physiology exhibits growth laws that relate the macromolecular composition of the cell to the growth rate. Recent work has shown that these empirical regularities can be derived from coarse-grained models of resource allocation. While these studies focus on steady-state growth, such conditions are rarely found in natural habitats, where microorganisms are continually challenged by environmental fluctuations. The aim of this paper is to extend the study of microbial growth strategies to dynamical environments, using a self-replicator model. We formulate dynamical growth maximization as an optimal control problem that can be solved using Pontryagin’s Maximum Principle. We compare this theoretical gold standard with different possible implementations of growth control in bacterial cells. We find that simple control strategies enabling growth-rate maximization at steady state are suboptimal for transitions from one growth regime to another, for example when shifting bacterial cells to a medium supporting a higher growth rate. A near-optimal control strategy in dynamical conditions is shown to require information on several, rather than a single physiological variable. Interestingly, this strategy has structural analogies with the regulation of ribosomal protein synthesis by ppGpp in the enterobacterium Escherichia coli. It involves sensing a mismatch between precursor and ribosome concentrations, as well as the adjustment of ribosome synthesis in a switch-like manner. Our results show how the capability of regulatory systems to integrate information about several physiological variables is critical for optimizing growth in a changing environment. PMID:26958858

  15. Larval developmental rate, metabolic rate and future growth performance in Atlantic salmon

    DEFF Research Database (Denmark)

    Serrano, Jonathan Vaz; Åberg, Madelene; Gjoen, Hans Magnus;

    2009-01-01

    Previous studies in salmonids suggest a link between larval developmental rate, metabolic rate, and future growth. However, the connection between growth during exogenous and endogenous feeding is still debated. In the current study, a positive relationship between larval developmental rate, quan...

  16. Allometries of maximum growth rate versus body mass at maximum growth indicate that non-avian dinosaurs had growth rates typical of fast growing ectothermic sauropsids.

    Directory of Open Access Journals (Sweden)

    Jan Werner

    Full Text Available We tested if growth rates of recent taxa are unequivocally separated between endotherms and ectotherms, and compared these to dinosaurian growth rates. We therefore performed linear regression analyses on the log-transformed maximum growth rate against log-transformed body mass at maximum growth for extant altricial birds, precocial birds, eutherians, marsupials, reptiles, fishes and dinosaurs. Regression models of precocial birds (and fishes strongly differed from Case's study (1978, which is often used to compare dinosaurian growth rates to those of extant vertebrates. For all taxonomic groups, the slope of 0.75 expected from the Metabolic Theory of Ecology was statistically supported. To compare growth rates between taxonomic groups we therefore used regressions with this fixed slope and group-specific intercepts. On average, maximum growth rates of ectotherms were about 10 (reptiles to 20 (fishes times (in comparison to mammals or even 45 (reptiles to 100 (fishes times (in comparison to birds lower than in endotherms. While on average all taxa were clearly separated from each other, individual growth rates overlapped between several taxa and even between endotherms and ectotherms. Dinosaurs had growth rates intermediate between similar sized/scaled-up reptiles and mammals, but a much lower rate than scaled-up birds. All dinosaurian growth rates were within the range of extant reptiles and mammals, and were lower than those of birds. Under the assumption that growth rate and metabolic rate are indeed linked, our results suggest two alternative interpretations. Compared to other sauropsids, the growth rates of studied dinosaurs clearly indicate that they had an ectothermic rather than an endothermic metabolic rate. Compared to other vertebrate growth rates, the overall high variability in growth rates of extant groups and the high overlap between individual growth rates of endothermic and ectothermic extant species make it impossible to rule

  17. Modelling urban growth in the Indo-Gangetic plain using nighttime OLS data and cellular automata

    Science.gov (United States)

    Roy Chowdhury, P. K.; Maithani, Sandeep

    2014-12-01

    The present study demonstrates the applicability of the Operational Linescan System (OLS) sensor in modelling urban growth at regional level. The nighttime OLS data provides an easy, inexpensive way to map urban areas at a regional scale, requiring a very small volume of data. A cellular automata (CA) model was developed for simulating urban growth in the Indo-Gangetic plain; using OLS data derived maps as input. In the proposed CA model, urban growth was expressed in terms of causative factors like economy, topography, accessibility and urban infrastructure. The model was calibrated and validated based on OLS data of year 2003 and 2008 respectively using spatial metrics measures and subsequently the urban growth was predicted for the year 2020. The model predicted high urban growth in North Western part of the study area, in south eastern part growth would be concentrated around two cities, Kolkata and Howrah. While in the middle portion of the study area, i.e., Jharkhand, Bihar and Eastern Uttar Pradesh, urban growth has been predicted in form of clusters, mostly around the present big cities. These results will not only provide an input to urban planning but can also be utilized in hydrological and ecological modelling which require an estimate of future built up areas especially at regional level.

  18. Can we estimate bacterial growth rates from ribosomal RNA content?

    Energy Technology Data Exchange (ETDEWEB)

    Kemp, P.F.

    1995-12-31

    Several studies have demonstrated a strong relationship between the quantity of RNA in bacterial cells and their growth rate under laboratory conditions. It may be possible to use this relationship to provide information on the activity of natural bacterial communities, and in particular on growth rate. However, if this approach is to provide reliably interpretable information, the relationship between RNA content and growth rate must be well-understood. In particular, a requisite of such applications is that the relationship must be universal among bacteria, or alternately that the relationship can be determined and measured for specific bacterial taxa. The RNA-growth rate relationship has not been used to evaluate bacterial growth in field studies, although RNA content has been measured in single cells and in bulk extracts of field samples taken from coastal environments. These measurements have been treated as probable indicators of bacterial activity, but have not yet been interpreted as estimators of growth rate. The primary obstacle to such interpretations is a lack of information on biological and environmental factors that affect the RNA-growth rate relationship. In this paper, the available data on the RNA-growth rate relationship in bacteria will be reviewed, including hypotheses regarding the regulation of RNA synthesis and degradation as a function of growth rate and environmental factors; i.e. the basic mechanisms for maintaining RNA content in proportion to growth rate. An assessment of the published laboratory and field data, the current status of this research area, and some of the remaining questions will be presented.

  19. Growth rate and crystal habit of germanium telluride

    International Nuclear Information System (INIS)

    Controlling steps of GeTe crystal growth under different experimental conditions were determined. Diffusion coefficient of GeTe molecules in argon was found, and condensation coefficient was evaluated. Influence of mass transfer rate in a gas on crystal habit was studied: crystals have round faces at low rates and dendritic growth is observed at high rates. Optimal conditions of growing edged crystals of germanium telluride of α-3 mm size were determined

  20. Aortic growth rates in chronic aortic dissection

    International Nuclear Information System (INIS)

    Aim: To determine and compare rates of descending aortic enlargement and complications in chronic aortic dissection with and without a proximal aortic graft. Methods and materials: Fifty-two patients with dissection involving the descending aorta and who had undergone at least two computed tomography (CT) examinations at our institution between November, 1993 and February, 2004 were identified, including 24 non-operated patients (four type A, 20 type B) and 28 operated patients (type A). CT examinations per patient ranged from two to 10, and follow-up ranged from 1-123 months (mean 49 months, median 38.5 months). On each CT image, the aortic short axis (SA), false lumen (FL), and true lumen (TL) diameters were measured at the longitudinal midpoint of the dissection and at the point of maximum aortic diameter. Complications were tabulated, including aortic rupture and aortic enlargement requiring surgery. Results: For non-operated patients, the midpoint and maximum point SA, TL, and FL diameters increased significantly over time. For operated patients, the midpoint and maximum point SA and FL diameters increased significantly over time. In both groups, aortic enlargement was predominantly due to FL expansion. Diameter increases in non-operated patients were significantly larger than those in operated patients. The rate of change in aortic diameter was constant, regardless of aortic size. Four non-operated and six operated patients developed aortic complications. Conclusions: In patients with a dissection involving the descending thoracic aorta, the FL increased in diameter over time, at a constant rate, and to a greater degree in non-operated patients (mostly type B) compared with operated patients (all type A)

  1. Growth Rates in the Quaquaversal Tiling

    OpenAIRE

    Draco, Brimstone; Sadun, Lorenzo; Van Wieren, Douglas

    1998-01-01

    Conway and Radin's ``quaquaversal'' tiling of R^3 is known to exhibit statistical rotational symmetry in the infinite volume limit. A finite patch, however, cannot be perfectly isotropic, and we compute the rates at which the anisotropy scales with size. In a sample of volume N, tiles appear in O(N^{1/6}) distinct orientations. However, the orientations are not uniformly populated. A small (O(N^{1/84})) set of these orientations account for the majority of the tiles. Furthermore, these orient...

  2. A quantitative theory of solid tumor growth, metabolic rate and vascularization.

    Directory of Open Access Journals (Sweden)

    Alexander B Herman

    Full Text Available The relationships between cellular, structural and dynamical properties of tumors have traditionally been studied separately. Here, we construct a quantitative, predictive theory of solid tumor growth, metabolic rate, vascularization and necrosis that integrates the relationships between these properties. To accomplish this, we develop a comprehensive theory that describes the interface and integration of the tumor vascular network and resource supply with the cardiovascular system of the host. Our theory enables a quantitative understanding of how cells, tissues, and vascular networks act together across multiple scales by building on recent theoretical advances in modeling both healthy vasculature and the detailed processes of angiogenesis and tumor growth. The theory explicitly relates tumor vascularization and growth to metabolic rate, and yields extensive predictions for tumor properties, including growth rates, metabolic rates, degree of necrosis, blood flow rates and vessel sizes. Besides these quantitative predictions, we explain how growth rates depend on capillary density and metabolic rate, and why similar tumors grow slower and occur less frequently in larger animals, shedding light on Peto's paradox. Various implications for potential therapeutic strategies and further research are discussed.

  3. Rerouting Cellular Electron Flux To Increase the Rate of Biological Methane Production

    OpenAIRE

    Catlett, Jennie L.; Ortiz, Alicia M.; Buan, Nicole R.

    2015-01-01

    Methanogens are anaerobic archaea that grow by producing methane, a gas that is both an efficient renewable fuel and a potent greenhouse gas. We observed that overexpression of the cytoplasmic heterodisulfide reductase enzyme HdrABC increased the rate of methane production from methanol by 30% without affecting the growth rate relative to the parent strain. Hdr enzymes are essential in all known methane-producing archaea. They function as the terminal oxidases in the methanogen electron trans...

  4. Emergent Behavior from A Cellular Automaton Model for Invasive Tumor Growth in Heterogeneous Microenvironments

    CERN Document Server

    Jiao, Yang

    2011-01-01

    Understanding tumor invasion and metastasis is of crucial importance for both fundamental cancer research and clinical practice. In vitro experiments have established that the invasive growth of malignant tumors is characterized by the dendritic invasive branches composed of chains of tumor cells emanating from the primary tumor mass. The preponderance of previous tumor simulations focused on non-invasive (or proliferative) growth. The formation of the invasive cell chains and their interactions with the primary tumor mass and host microenvironment are not well understood. Here, we present a novel cellular automaton (CA) model that enables one to efficiently simulate invasive tumor growth in a heterogeneous host microenvironment. By taking into account a variety of microscopic-scale tumor-host interactions, including the short-range mechanical interactions between tumor cells and tumor stroma, degradation of extracellular matrix by the invasive cells and oxygen/nutrient gradient driven cell motions, our CA mo...

  5. Phase transition in the economically modeled growth of a cellular nervous system

    CERN Document Server

    Nicosia, Vincenzo; Schafer, William R; Latora, Vito; Bullmore, Edward T; 10.1073/pnas.1300753110

    2013-01-01

    Spatially-embedded complex networks, such as nervous systems, the Internet and transportation networks, generally have non-trivial topological patterns of connections combined with nearly minimal wiring costs. However the growth rules shaping these economical trade-offs between cost and topology are not well understood. Here we study the cellular nervous system of the nematode worm C. elegans, together with information on the birth times of neurons and on their spatial locations. We find that the growth of this network undergoes a transition from an accelerated to a constant increase in the number of links (synaptic connections) as a function of the number of nodes (neurons). The time of this phase transition coincides closely with the observed moment of hatching, when development switches metamorphically from oval to larval stages. We use graph analysis and generative modelling to show that the transition between different growth regimes, as well as its coincidence with the moment of hatching, can be explain...

  6. Redox Homeostasis and Cellular Antioxidant Systems: Crucial Players in Cancer Growth and Therapy

    Directory of Open Access Journals (Sweden)

    Barbara Marengo

    2016-01-01

    Full Text Available Reactive oxygen species (ROS and their products are components of cell signaling pathways and play important roles in cellular physiology and pathophysiology. Under physiological conditions, cells control ROS levels by the use of scavenging systems such as superoxide dismutases, peroxiredoxins, and glutathione that balance ROS generation and elimination. Under oxidative stress conditions, excessive ROS can damage cellular proteins, lipids, and DNA, leading to cell damage that may contribute to carcinogenesis. Several studies have shown that cancer cells display an adaptive response to oxidative stress by increasing expression of antioxidant enzymes and molecules. As a double-edged sword, ROS influence signaling pathways determining beneficial or detrimental outcomes in cancer therapy. In this review, we address the role of redox homeostasis in cancer growth and therapy and examine the current literature regarding the redox regulatory systems that become upregulated in cancer and their role in promoting tumor progression and resistance to chemotherapy.

  7. Applying Cellular Automata for Simulating and Assessing Urban Growth Scenario Based in Nairobi, Kenya

    Directory of Open Access Journals (Sweden)

    Kenneth Mubea

    2014-01-01

    Full Text Available This research explores urban growth based scenarios for the city of Nairobi using a cellular automata urban growth model (UGM. African cities have experienced rapid urbanization over the last decade due to increased population growth and high economic activities. We used multi-temporal Landsat imageries for 1976, 1986, 2000 and 2010 to investigate urban land-use changes in Nairobi. Our UGM used data from urban land-use of 1986 and 2010, road data, slope data and exclusion layer. Monte-Carlo technique was used for model calibration and Multi Resolution Validation (MRV technique for validation. Simulation of urban land-use was done up to the year 2030 when Kenya plans to attain Vision 2030. Three scenarios were explored in the urban modelling process; unmanaged growth with no restriction on environmental areas, managed growth with moderate protection, and a managed growth with maximum protection on forest, agricultural areas, and urban green. Thus alternative scenario development using UGM is useful for planning purposes so as to ensure sustainable development is achieved. UGM provides quantitative, visual, spatial and temporal information which aid policy and decision makers can make informed decisions.

  8. Crack growth rate of PWR piping

    International Nuclear Information System (INIS)

    The Aquitaine 1 program, carried out jointly by FRAMATOME and the CEA is intended to improve knowledge about cracking mechanisms in AISI 316 L austenitic stainless steel under conditions similar to those of the PWR environment (irradiation excluded). Experiments of fatigue crack growth are performed on piping elements, scale 1/4 of primary pipings, by means of internal hydraulic cyclic pressure. Interpretation of results requires a knowledge of the stress intensity factor Ksub(I) at the front of the crack. Results of a series of calculations of Ksub(I) obtained by different methods for defects of finite and infinite length (three dimensional calculations) are given in the paper. The following have been used: calculations by finite elements, calculations by weight function. Notches are machined on the test pipes, which are subjected to internal hydraulic pressure cycles, under cold conditions, to initiate a crack at the tip of the notch. They are then cycled at a frequency of 4 cycles/hour on on water demineralised loop at a temperature of 2800C, the pressure varying at each cycle between approximately 160 bars and 3 bars. After each test, a specimen containing the defect is taken from the pipe for micrographic analysis. For the first test the length of the longitudinal external defect is assumed infinite. The number of cycles carried out is 5880 cycles. Two defects are machined in the tube for the second test. The number of cycles carried out is N = 440. The tests are performed under hot conditions (T = 2800C). For the third test two defects are analysed under cold and hot conditions. The number of cycles carried out for the external defect is 7000 when hot and 90000 when cold. The number of cycles for the internal defect is 1650 when hot and 68000 when cold. In order to interpret the results, the data da/dN are plotted on a diagram versus ΔK. Comparisons are made between these results and the curves from laboratory tests

  9. Effect of cell size and shear stress on bacterium growth rate

    Science.gov (United States)

    Fadlallah, Hadi; Jarrahi, Mojtaba; Herbert, Éric; Peerhossaini, Hassan; PEF Team

    2015-11-01

    Effect of shear stress on the growth rate of Synechocystis and Chlamydomonas cells is studied. An experimental setup was prepared to monitor the growth rate of the microorganisms versus the shear rate inside a clean room, under atmospheric pressure and 20 °C temperature. Digital magnetic agitators are placed inside a closed chamber provided with airflow, under a continuous uniform light intensity over 4 weeks. In order to study the effect of shear stress on the growth rate, different frequencies of agitation are tested, 2 vessels filled with 150 ml of each specie were placed on different agitating system at the desired frequency. The growth rate is monitored daily by measuring the optical density and then correlate it to the cellular concentration. The PH was adjusted to 7 in order to maintain the photosynthetic activity. Furthermore, to measure the shear stress distribution, the flow velocity field was measured using PIV. Zones of high and low shear stress were identified. Results show that the growth rate is independent of the shear stress magnitude, mostly for Synechocystis, and with lower independency for Chlamydomonas depending on the cell size for each species.

  10. Cellular and molecular regulation of muscle growth and development in meat animals.

    Science.gov (United States)

    Dayton, W R; White, M E

    2008-04-01

    Although in vivo and in vitro studies have established that anabolic steroids, transforming growth factor-beta (TGF-beta), and myostatin affect muscle growth in meat-producing animals, their mechanisms of action are not completely understood. Anabolic steroids have been widely used as growth promoters in feedlot cattle for over 50 yr. A growing body of evidence suggests that increased muscle levels of IGF-I and increased muscle satellite cell numbers play a role in anabolic steroid enhanced muscle growth. In contrast to anabolic steroids, the members of the TGF-beta-myostatin family suppress muscle growth in vivo and suppress both proliferation and differentiation of cultured myogenic cells. Recent evidence suggests that IGFBP-3 and IGFBP-5 play a role in mediating the proliferation-suppressing actions of both TGF-beta and myostatin on cultured myogenic cells. Consequently, this review will focus on the roles of IGF-I and IGFBP in the cellular and molecular mechanisms of action of anabolic steroids and TGF-beta and myostatin, respectively. PMID:17709769

  11. Protein thermodynamics can be predicted directly from biological growth rates.

    Directory of Open Access Journals (Sweden)

    Ross Corkrey

    Full Text Available Life on Earth is capable of growing from temperatures well below freezing to above the boiling point of water, with some organisms preferring cooler and others hotter conditions. The growth rate of each organism ultimately depends on its intracellular chemical reactions. Here we show that a thermodynamic model based on a single, rate-limiting, enzyme-catalysed reaction accurately describes population growth rates in 230 diverse strains of unicellular and multicellular organisms. Collectively these represent all three domains of life, ranging from psychrophilic to hyperthermophilic, and including the highest temperature so far observed for growth (122 °C. The results provide credible estimates of thermodynamic properties of proteins and obtain, purely from organism intrinsic growth rate data, relationships between parameters previously identified experimentally, thus bridging a gap between biochemistry and whole organism biology. We find that growth rates of both unicellular and multicellular life forms can be described by the same temperature dependence model. The model results provide strong support for a single highly-conserved reaction present in the last universal common ancestor (LUCA. This is remarkable in that it means that the growth rate dependence on temperature of unicellular and multicellular life forms that evolved over geological time spans can be explained by the same model.

  12. Synthesis of cellular organelles containing nano-magnets stunts growth of magnetotactic bacteria.

    Science.gov (United States)

    Naresh, Mohit; Hasija, Vivek; Sharma, Megha; Mittal, Aditya

    2010-07-01

    Magnetotactic bacteria are unique prokaryotes possessing the feature of cellular organelles called magnetosomes (membrane bound 40-50 nm vesicles entrapping a magnetic nano-crystal of magnetite or greigite). The obvious energetic impact of sophisticated eukaryotic-like membrane-bound organelle assembly on a presumably simpler prokaryotic system is not addressed in literature. In this work, while presenting evidence of direct coupling of carbon source consumption to synthesis of magnetosomes, we provide the first experimentally derived estimate of energy for organelle synthesis by Magnetospirillum gryphiswaldense as approximately 5 nJoules per magnetosome. Considering our estimate of approximately 0.2 microJoules per bacterial cell as the energy required for growth, we show that the energetic load of organelle synthesis results in stunting of cell growth. We also show that removal of soluble iron or sequestration by exogenous compounds in the bacterial cell cultures reverses the impact of the excess metabolic load exerted during magnetosomal synthesis. Thus, by taking advantage of the magnetotactic bacterial system we present the first experimental evidence for the presumed energy consumption during assembly of naturally occurring sub-100 nm intra-cellular organelles. PMID:21128392

  13. Rerouting Cellular Electron Flux To Increase the Rate of Biological Methane Production.

    Science.gov (United States)

    Catlett, Jennie L; Ortiz, Alicia M; Buan, Nicole R

    2015-10-01

    Methanogens are anaerobic archaea that grow by producing methane, a gas that is both an efficient renewable fuel and a potent greenhouse gas. We observed that overexpression of the cytoplasmic heterodisulfide reductase enzyme HdrABC increased the rate of methane production from methanol by 30% without affecting the growth rate relative to the parent strain. Hdr enzymes are essential in all known methane-producing archaea. They function as the terminal oxidases in the methanogen electron transport system by reducing the coenzyme M (2-mercaptoethane sulfonate) and coenzyme B (7-mercaptoheptanoylthreonine sulfonate) heterodisulfide, CoM-S-S-CoB, to regenerate the thiol-coenzymes for reuse. In Methanosarcina acetivorans, HdrABC expression caused an increased rate of methanogenesis and a decrease in metabolic efficiency on methylotrophic substrates. When acetate was the sole carbon and energy source, neither deletion nor overexpression of HdrABC had an effect on growth or methane production rates. These results suggest that in cells grown on methylated substrates, the cell compensates for energy losses due to expression of HdrABC with an increased rate of substrate turnover and that HdrABC lacks the appropriate electron donor in acetate-grown cells. PMID:26162885

  14. Investigation of growth rate dispersion in lactose crystallisation by AFM

    Science.gov (United States)

    Dincer, T. D.; Ogden, M. I.; Parkinson, G. M.

    2014-09-01

    α-Lactose monohydrate crystals have been reported to exhibit growth rate dispersion (GRD). Variation in surface dislocations has been suggested as the cause of GRD, but this has not been further investigated to date. In this study, growth rate dispersion and the change in morphology were investigated in situ and via bottle roller experiments. The surfaces of the (0 1 0) faces of crystals were examined with Atomic Force Microscopy. Smaller, slow growing crystals tend to have smaller (0 1 0) faces with narrow bases and displayed a single double spiral in the centre of the crystal with 2 nm high steps. Additional double spirals in other crystals resulted in faster growth rates. Large, fast growing crystals were observed to have larger (0 1 0) faces with fast growth in both the a and b directions (giving a broader crystal base) with macro steps parallel to the (c direction). The number and location of spirals or existence of macro steps appears to influence the crystal morphology, growth rates and growth rate dispersion in lactose crystals.

  15. Insights for Analyzing Earnings Growth Rates: A Case Study.

    Science.gov (United States)

    Hannah, Richard L.

    1994-01-01

    A study at one public university investigated the annualized rate of salary/wage increase of employees from the time of hiring until July 1992. It examined promotion patterns, equity adjustments, employee degree acquisition, and certification of clerical workers. The study underscored the wide variation in earnings growth rates due in large part…

  16. Urban Public Pension, Replacement Rates and Population Growth Rate in China

    OpenAIRE

    Yang, Zaigui

    2009-01-01

    This paper uses an overlapping generations model to investigate the urban public pension in China. It examines the effects of the replacement rates and population growth rate on the capital-labor ratio, pension benefits, consumption and utility, and finds the optimal replacement rate. It is shown that raising the individual account benefit replacement rate only induces the increase in the individual account benefits. Raising the social pool benefit replacement rate induces the increase in the...

  17. Re-assessing copepod growth using the Moult Rate method

    DEFF Research Database (Denmark)

    Hirst, Andrew G.; Keister, J. E.; Richardson, A. J.; Ward, P.; Shreeve, R. S.; Escribano, R.

    2014-01-01

    method has been shown to have serious flaws. Here we re-examine the results from the majority of published MR method studies and re-estimate growth rates using the modified Moult Rate (MMR) method, which ascribes changes in mass to the appropriate time period over which it was accrued. The MR method has...... typically over-estimated growth rates (on 80% of occasions) for life stages where the subsequent stage is actively moulting; the median and mean MR values are 138 and 164%, respectively, of the corrected MMR values. We were unable to correct the original data for life stages that are followed by a non...

  18. Greenhouse Gas Growth Rates from AIRS Hyperspectral Radiance Time Series

    Science.gov (United States)

    Strow, L. L.; Desouza-Machado, S. G.; Hannon, S.; Imbiriba, B.; Schou, P.

    2009-12-01

    The AIRS seven year hyperspectral radiance record provides an ideal platform for measurings growth rates of infrared active minor gases, especially carbon dioxide and methane. The largest changes in CLARREO radiances will likely be due to increasing carbon dioxide and other greenhouse gases. We have produced a 5+ year record of almost cloud-free AIRS radiances, from which we have derived the radiance anomaly and linear time rate of change. The source of these radiances are the L1b radiances corrected for small frequency drifts. Growth rates of carbon dioxide, nitrous oxide, methane, ozone, and CFC11 are simultaneously derived from zonal averages of these radiance rates for tropics, and mid-latitude northern and southern hemispheres. The effective linear rate of change of ~5 layers of water vapor and temperature, plus the surface temperature are also simultaneously derived with the minor gas rates. No model data or prior is needed and more than 1000 channels are used in the fit. Sampling issues may preclude the use of the mid-latitude temperature and water vapor rates for climate analysis, but possibly not for the tropics. The resulting greenhouse gas growth rates agree very well with in-situ measurements, which suggests high radiometric stability for AIRS. Radiance intercomparisons for climate analysis between IASI and AIRS will also be presented.

  19. Growth rate in the dynamical dark energy models

    Energy Technology Data Exchange (ETDEWEB)

    Avsajanishvili, Olga [Ilia State University, Abastumani Astrophysical Observatory, Tbilisi (Georgia); Arkhipova, Natalia A. [Astro Space Center of P.N. Lebedev Physical Institute, Russia, Moscow (Russian Federation); Samushia, Lado [Kansas State University, Department of Physics, Manhattan, KS (United States); Ilia State University, Abastumani Astrophysical Observatory, Tbilisi (Georgia); Kahniashvili, Tina [Carnegie Mellon University, McWilliams Center for Cosmology and Department of Physics, Pittsburgh, PA (United States); Laurentian University, Department of Physics, Sudbury, ON (Canada); Ilia State University, Abastumani Astrophysical Observatory, Tbilisi (Georgia)

    2014-11-15

    Dark energy models with a slowly rolling cosmological scalar field provide a popular alternative to the standard, time-independent cosmological constant model. We study the simultaneous evolution of background expansion and growth in the scalar field model with the Ratra-Peebles self-interaction potential. We use recent measurements of the linear growth rate and the baryon acoustic oscillation peak positions to constrain the model parameter α that describes the steepness of the scalar field potential. (orig.)

  20. Effects of cellular iron deficiency on the formation of vascular endothelial growth factor and angiogenesis. Iron deficiency and angiogenesis

    Directory of Open Access Journals (Sweden)

    Eckard Jonathan

    2010-08-01

    Full Text Available Abstract Background Young women diagnosed with breast cancer are known to have a higher mortality rate from the disease than older patients. Specific risk factors leading to this poorer outcome have not been identified. In the present study, we hypothesized that iron deficiency, a common ailment in young women, contributes to the poor outcome by promoting the hypoxia inducible factor-1α (HIF-1α and vascular endothelial growth factor (VEGF formation. This hypothesis was tested in an in vitro cell culture model system. Results Human breast cancer MDA-MB-231 cells were transfected with transferrin receptor-1 (TfR1 shRNA to constitutively impair iron uptake. Cellular iron status was determined by a set of iron proteins and angiogenesis was evaluated by levels of VEGF in cells as well as by a mouse xenograft model. Significant decreases in ferritin with concomitant increases in VEGF were observed in TfR1 knockdown MDA-MB-231 cells when compared to the parental cells. TfR1 shRNA transfectants also evoked a stronger angiogenic response after the cells were injected subcutaneously into nude mice. The molecular mechanism appears that cellular iron deficiency elevates VEGF formation by stabilizing HIF-1α. This mechanism is also true in human breast cancer MCF-7 and liver cancer HepG2 cells. Conclusions Cellular iron deficiency increased HIF-1α, VEGF, and angiogenesis, suggesting that systemic iron deficiency might play an important part in the tumor angiogenesis and recurrence in this young age group of breast cancer patients.

  1. Crystal-face growth rate: role of the neighbouring concentration

    International Nuclear Information System (INIS)

    A study has been made of the phenomena occurring in the neighbourhood of a growing crystal-face, with the help of several methods based on interferometric observation. If the system is considered at a given moment, it is possible to express the growth rate of the crystal in two ways: 1) using the origin of the solute contributing to the growth, by application of Fick's law modified in certain cases by a correction factor involving the absolute value of the concentration near the crystal face. 2) directly, using the supersaturation in the crystal-face neighbourhood. On the other hand, if an attempt is made to take into account the changes in growth rate with time, it is seen that this rate is not dependent on diffusion phenomena, but that the convection currents in the solution play an important role. (author)

  2. Influence of corruption on economic growth rate and foreign investment

    Science.gov (United States)

    Podobnik, Boris; Shao, Jia; Njavro, Djuro; Ivanov, Plamen Ch.; Stanley, H. E.

    2008-06-01

    We analyze the dependence of the Gross Domestic Product ( GDP) per capita growth rates on changes in the Corruption Perceptions Index ( CPI). For the period 1999 2004 for all countries in the world, we find on average that an increase of CPI by one unit leads to an increase of the annual GDP per capita growth rate by 1.7%. By regressing only the European countries with transition economies, we find that an increase of CPI by one unit generates an increase of the annual GDP per capita growth rate by 2.4%. We also analyze the relation between foreign direct investments received by different countries and CPI, and we find a statistically significant power-law functional dependence between foreign direct investment per capita and the country corruption level measured by the CPI. We introduce a new measure to quantify the relative corruption between countries based on their respective wealth as measured by GDP per capita.

  3. Radiocarbon Based Ages and Growth Rates: Hawaiian Deep Sea Corals

    Energy Technology Data Exchange (ETDEWEB)

    Roark, E B; Guilderson, T P; Dunbar, R B; Ingram, B L

    2006-01-13

    The radial growth rates and ages of three different groups of Hawaiian deep-sea 'corals' were determined using radiocarbon measurements. Specimens of Corallium secundum, Gerardia sp., and Leiopathes glaberrima, were collected from 450 {+-} 40 m at the Makapuu deep-sea coral bed using a submersible (PISCES V). Specimens of Antipathes dichotoma were collected at 50 m off Lahaina, Maui. The primary source of carbon to the calcitic C. secundum skeleton is in situ dissolved inorganic carbon (DIC). Using bomb {sup 14}C time markers we calculate radial growth rates of {approx} 170 {micro}m y{sup -1} and ages of 68-75 years on specimens as tall as 28 cm of C. secundum. Gerardia sp., A. dichotoma, and L. glaberrima have proteinaceous skeletons and labile particulate organic carbon (POC) is their primary source of architectural carbon. Using {sup 14}C we calculate a radial growth rate of 15 {micro}m y{sup -1} and an age of 807 {+-} 30 years for a live collected Gerardia sp., showing that these organisms are extremely long lived. Inner and outer {sup 14}C measurements on four sub-fossil Gerardia spp. samples produce similar growth rate estimates (range 14-45 {micro}m y{sup -1}) and ages (range 450-2742 years) as observed for the live collected sample. Similarly, with a growth rate of < 10 {micro}m y{sup -1} and an age of {approx}2377 years, L. glaberrima at the Makapuu coral bed, is also extremely long lived. In contrast, the shallow-collected A. dichotoma samples yield growth rates ranging from 130 to 1,140 {micro}m y{sup -1}. These results show that Hawaiian deep-sea corals grow more slowly and are older than previously thought.

  4. On oscillatory microstructure during cellular growth of directionally solidified Sn–36at.%Ni peritectic alloy

    Science.gov (United States)

    Peng, Peng; Li, Xinzhong; Li, Jiangong; Su, Yanqing; Guo, Jingjie

    2016-04-01

    An oscillatory microstructure has been observed during deep-cellular growth of directionally solidified Sn–36at.%Ni hyperperitectic alloy containing intermetallic compounds with narrow solubility range. This oscillatory microstructure with a dimension of tens of micrometers has been observed for the first time. The morphology of this wave-like oscillatory structure is similar to secondary dendrite arms, and can be observed only in some local positions of the sample. Through analysis such as successive sectioning of the sample, it can be concluded that this oscillatory microstructure is caused by oscillatory convection of the mushy zone during solidification. And the influence of convection on this oscillatory microstructure was characterized through comparison between experimental and calculations results on the wavelength. Besides, the change in morphology of this oscillatory microstructure has been proved to be caused by peritectic transformation during solidification. Furthermore, the melt concentration increases continuously during solidification of intermetallic compounds with narrow solubility range, which helps formation of this oscillatory microstructure.

  5. Nanocrystalline silicon prepared at high growth rate using helium dilution

    Indian Academy of Sciences (India)

    Koyel Bhattacharya; Debajyoti Das

    2008-06-01

    Growth and optimization of the nanocrystalline silicon (nc-Si : H) films have been studied by varying the electrical power applied to the helium diluted silane plasma in RF glow discharge. Wide optical gap and conducting intrinsic nanocrystalline silicon network of controlled crystalline volume fraction and oriented crystallographic lattice planes have been obtained at a reasonably high growth rate from helium diluted silane plasma, without using hydrogen. Improving crystallinity in the network comprising ∼ 10 nm Si-nanocrystallites and contributing optical gap widening, conductivity ascending and that obtained during simultaneous escalation of the deposition rate, promises significant technological impact.

  6. Orbit width scaling of TAE instability growth rate

    International Nuclear Information System (INIS)

    The growth rate of Toroidal Alfven Eigenmodes (TAE) driven unstable by resonant coupling of energetic charged particles is evaluated in the ballooning limit over a wide range of parameters. All damping effects are ignored. Variations in orbit width, aspect ratio, and the ratio of alfven velocity to energetic particle birth velocity, are explored. The relative contribution of passing and trapped particles, and finite Larmor radius effects, are also examined. The phase space location of resonant particles with interact strongly with the modes is described. The accuracy of the analytic results with respect to growth rate magnitude and parametric dependence is investigated by comparison with numerical results

  7. Stainless steels: general considerations and rates of crack growth

    International Nuclear Information System (INIS)

    This report describes the different types of stainless steels, and presents the laws governing the rates of crack growth for several stainless steels extensively used for the manufacture of structures in nuclear power plants. The laws are not discussed in detail in the report. After a brief review of the development of stainless steels, the main categories of stainless steels, their mechanical characteristics and corrosion resistance, are presented. Finally, the rates of crack growth are presented for various stainless steels, mainly austenitic. The study overall aim is an investigation of the cracking in the 900 MWe primary pump thermal barriers and shafts

  8. The growth rate of gas hydrate from refrigerant R12

    Energy Technology Data Exchange (ETDEWEB)

    Kendoush, Abdullah Abbas; Jassim, Najim Abid [Centre of Engineering Physics, Ministry of Sciences and Technology, P.O. Box 765, Baghdad (Iraq); Joudi, Khalid A. [Al-Nahrain University, Baghdad (Iraq)

    2006-07-15

    Experimental and theoretical investigations were presented dealing with three phase direct-contact heat transfer by evaporation of refrigerant drops in an immiscible liquid. Refrigerant R12 was used as the dispersed phase, while water and brine were the immiscible continuous phase. A numerical solution is presented to predict the formation rate of gas hydrates in test column. The solution provided an acceptable agreement when compared with experimental results. The gas hydrate growth rate increased with time. It increased with increasing dispersed phase flow rate. The presence of surface-active sodium chloride in water had a strong inhibiting effect on the gas hydrate formation rate. (author)

  9. CK2 activity is modulated by growth rate in Saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    Research highlights: → CK2 subunits are nuclear both in glucose and in ethanol growing yeast cells. → CK2 activity is modulated in S. cerevisiae. → CK2 activity is higher in conditions supporting higher growth rates. → Vmax is higher in faster growing cells, while Km is not affected. -- Abstract: CK2 is a highly conserved protein kinase controlling different cellular processes. It shows a higher activity in proliferating mammalian cells, in various types of cancer cell lines and tumors. The findings presented herein provide the first evidence of an in vivo modulation of CK2 activity, dependent on growth rate, in Saccharomyces cerevisiae. In fact, CK2 activity, assayed on nuclear extracts, is shown to increase in exponential growing batch cultures at faster growth rate, while localization of catalytic and regulatory subunits is not nutritionally modulated. Differences in intracellular CK2 activity of glucose- and ethanol-grown cells appear to depend on both increase in molecule number and kcat. Also in chemostat cultures nuclear CK2 activity is higher in faster growing cells providing the first unequivocal demonstration that growth rate itself can affect CK2 activity in a eukaryotic organism.

  10. Quorum Sensing Influences Vibrio harveyi Growth Rates in a Manner Not Fully Accounted For by the Marker Effect of Bioluminescence

    Science.gov (United States)

    Nackerdien, Zeena E.; Keynan, Alexander; Bassler, Bonnie L.; Lederberg, Joshua; Thaler, David S.

    2008-01-01

    Background The light-emitting Vibrios provide excellent material for studying the interaction of cellular communication with growth rate because bioluminescence is a convenient marker for quorum sensing. However, the use of bioluminescence as a marker is complicated because bioluminescence itself may affect growth rate, e.g. by diverting energy. Methodology/Principal Findings The marker effect was explored via growth rate studies in isogenic Vibrio harveyi (Vh) strains altered in quorum sensing on the one hand, and bioluminescence on the other. By hypothesis, growth rate is energy limited: mutants deficient in quorum sensing grow faster because wild type quorum sensing unleashes bioluminescence and bioluminescence diverts energy. Findings reported here confirm a role for bioluminescence in limiting Vh growth rate, at least under the conditions tested. However, the results argue that the bioluminescence is insufficient to explain the relationship of growth rate and quorum sensing in Vh. A Vh mutant null for all genes encoding the bioluminescence pathway grew faster than wild type but not as fast as null mutants in quorum sensing. Vh quorum sensing mutants showed altered growth rates that do not always rank with their relative increase or decrease in bioluminescence. In addition, the cell-free culture fluids of a rapidly growing Vibrio parahaemolyticus (Vp) strain increased the growth rate of wild type Vh without significantly altering Vh's bioluminescence. The same cell-free culture fluid increased the bioluminescence of Vh quorum mutants. Conclusions/Significance The effect of quorum sensing on Vh growth rate can be either positive or negative and includes both bioluminescence-dependent and independent components. Bioluminescence tends to slow growth rate but not enough to account for the effects of quorum sensing on growth rate. PMID:18301749

  11. Quorum sensing influences Vibrio harveyi growth rates in a manner not fully accounted for by the marker effect of bioluminescence.

    Directory of Open Access Journals (Sweden)

    Zeena E Nackerdien

    Full Text Available BACKGROUND: The light-emitting Vibrios provide excellent material for studying the interaction of cellular communication with growth rate because bioluminescence is a convenient marker for quorum sensing. However, the use of bioluminescence as a marker is complicated because bioluminescence itself may affect growth rate, e.g. by diverting energy. METHODOLOGY/PRINCIPAL FINDINGS: The marker effect was explored via growth rate studies in isogenic Vibrio harveyi (Vh strains altered in quorum sensing on the one hand, and bioluminescence on the other. By hypothesis, growth rate is energy limited: mutants deficient in quorum sensing grow faster because wild type quorum sensing unleashes bioluminescence and bioluminescence diverts energy. Findings reported here confirm a role for bioluminescence in limiting Vh growth rate, at least under the conditions tested. However, the results argue that the bioluminescence is insufficient to explain the relationship of growth rate and quorum sensing in Vh. A Vh mutant null for all genes encoding the bioluminescence pathway grew faster than wild type but not as fast as null mutants in quorum sensing. Vh quorum sensing mutants showed altered growth rates that do not always rank with their relative increase or decrease in bioluminescence. In addition, the cell-free culture fluids of a rapidly growing Vibrio parahaemolyticus (Vp strain increased the growth rate of wild type Vh without significantly altering Vh's bioluminescence. The same cell-free culture fluid increased the bioluminescence of Vh quorum mutants. CONCLUSIONS/SIGNIFICANCE: The effect of quorum sensing on Vh growth rate can be either positive or negative and includes both bioluminescence-dependent and independent components. Bioluminescence tends to slow growth rate but not enough to account for the effects of quorum sensing on growth rate.

  12. The relationship between creep crack growth rates and creep-fatigue crack growth rates in austenitic Type 316 steel

    International Nuclear Information System (INIS)

    The relationship between high temperature crack growth rates in type 316 steel under creep conditions and combined creep-fatigue cycling is examined by consideration of the similarities between the underlying physical mechanisms of crack advance. In this way it is shown that creep crack growth rates may be used to estimate the limits to which creep-fatigue cycling can cause crack growth rates to accelerate in this steel. The usefulness of the derived limit is discussed with particular reference to practical stressing modes including load and displacement control. It is concluded that in type 316 steel there is little difference between the behaviour of a crack propagating under combined creep-fatigue cycling and a creep crack growing under some restraint. (author)

  13. Growth rates of modern science: A bibliometric analysis

    CERN Document Server

    Bornmann, Lutz

    2014-01-01

    Many studies in information science have looked at the growth of science. In this study, we re-examine the question of the growth of science. To do this we (i) use current data up to publication year 2012 and (ii) analyse it across all disciplines and also separately for the natural sciences and for the medical and health sciences. Furthermore, the data are analysed with an advanced statistical technique (segmented regression analysis) which can identify specific segments with similar growth rates in the history of science. The study is based on two different sets of bibliometric data: (1) The number of publications held as source items in the Web of Science (WoS, Thomson Reuters) per publication year and (2) the number of cited references in the publications of the source items per cited reference year. We have looked at the rate at which science has grown since the mid-1600s. In our analysis we identified three growth phases in the development of science, which each led to growth rates tripling in compariso...

  14. Upscaling Calcite Growth Rates From the Mesoscale to the Macroscale

    Energy Technology Data Exchange (ETDEWEB)

    Bracco, Jacquelyn N [ORNL; Stack, Andrew G [ORNL; Steefel, Carl I [Lawrence Berkeley National Laboratory (LBNL)

    2013-01-01

    Quantitative prediction of mineral reaction rates in the subsurface remains a daunting task partly because a key parameter for macroscopic models, the reactive site density, is poorly constrained. Here we report atomic force microscopy (AFM) measurements on the calcite surface of monomolecular step densities, treated as equivalent to the reactive site density, as a function of aqueous calcium-to-carbonate ratio and saturation index. Data for the obtuse step orientation are combined with existing step velocity measurements to generate a model that predicts overall macroscopic calcite growth rates. The model is quantitatively consistent with several published macroscopic rates under a range of alkaline solution conditions, particularly for two of the most comprehensive data sets without the need for additional fit parameters. The model reproduces peak growth rates and its functional form is simple enough to be incorporated into reactive transport or other macroscopic models designed for predictions in porous media. However, it currently cannot model equilibrium, pH effects, and may overestimate rates at high aqueous calcium-to-carbonate ratios. The discrepancies in rates at high calcium-to-carbonate ratios may be due to differences in pre-treatment, such as exposing the seed material to SI 1.0 to generate/develop growth hillocks, or other factors.

  15. Net Assimilation Rate Determines the Growth Rates of 14 Species of Subtropical Forest Trees.

    Directory of Open Access Journals (Sweden)

    Xuefei Li

    Full Text Available Growth rates are of fundamental importance for plants, as individual size affects myriad ecological processes. We determined the factors that generate variation in RGR among 14 species of trees and shrubs that are abundant in subtropical Chinese forests. We grew seedlings for two years at four light levels in a shade-house experiment. We monitored the growth of every juvenile plant every two weeks. After one and two years, we destructively harvested individuals and measured their functional traits and gas-exchange rates. After calculating individual biomass trajectories, we estimated relative growth rates using nonlinear growth functions. We decomposed the variance in log(RGR to evaluate the relationships of RGR with its components: specific leaf area (SLA, net assimilation rate (NAR and leaf mass ratio (LMR. We found that variation in NAR was the primary determinant of variation in RGR at all light levels, whereas SLA and LMR made smaller contributions. Furthermore, NAR was strongly and positively associated with area-based photosynthetic rate and leaf nitrogen content. Photosynthetic rate and leaf nitrogen concentration can, therefore, be good predictors of growth in woody species.

  16. Linear Stability of Binary Alloy Solidification for Unsteady Growth Rates

    Science.gov (United States)

    Mazuruk, K.; Volz, M. P.

    2010-01-01

    An extension of the Mullins and Sekerka (MS) linear stability analysis to the unsteady growth rate case is considered for dilute binary alloys. In particular, the stability of the planar interface during the initial solidification transient is studied in detail numerically. The rapid solidification case, when the system is traversing through the unstable region defined by the MS criterion, has also been treated. It has been observed that the onset of instability is quite accurately defined by the "quasi-stationary MS criterion", when the growth rate and other process parameters are taken as constants at a particular time of the growth process. A singular behavior of the governing equations for the perturbed quantities at the constitutional supercooling demarcation line has been observed. However, when the solidification process, during its transient, crosses this demarcation line, a planar interface is stable according to the linear analysis performed.

  17. Sales Growth Rate Forecasting Using Improved PSO and SVM

    Directory of Open Access Journals (Sweden)

    Xibin Wang

    2014-01-01

    Full Text Available Accurate forecast of the sales growth rate plays a decisive role in determining the amount of advertising investment. In this study, we present a preclassification and later regression based method optimized by improved particle swarm optimization (IPSO for sales growth rate forecasting. We use support vector machine (SVM as a classification model. The nonlinear relationship in sales growth rate forecasting is efficiently represented by SVM, while IPSO is optimizing the training parameters of SVM. IPSO addresses issues of traditional PSO, such as relapsing into local optimum, slow convergence speed, and low convergence precision in the later evolution. We performed two experiments; firstly, three classic benchmark functions are used to verify the validity of the IPSO algorithm against PSO. Having shown IPSO outperform PSO in convergence speed, precision, and escaping local optima, in our second experiment, we apply IPSO to the proposed model. The sales growth rate forecasting cases are used to testify the forecasting performance of proposed model. According to the requirements and industry knowledge, the sample data was first classified to obtain types of the test samples. Next, the values of the test samples were forecast using the SVM regression algorithm. The experimental results demonstrate that the proposed model has good forecasting performance.

  18. Computing the crystal growth rate by the interface pinning method

    DEFF Research Database (Denmark)

    Pedersen, Ulf Rørbæk; Hummel, Felix; Dellago, Christoph

    2015-01-01

    An essential parameter for crystal growth is the kinetic coefficient given by the proportionality between supercooling and average growth velocity. Here, we show that this coefficient can be computed in a single equilibrium simulation using the interface pinning method where two-phase configurati......An essential parameter for crystal growth is the kinetic coefficient given by the proportionality between supercooling and average growth velocity. Here, we show that this coefficient can be computed in a single equilibrium simulation using the interface pinning method where two...... is investigated in detail for the Lennard-Jones model. We find that the kinetic coefficient scales as the inverse square-root of temperature along the high temperature part of the melting line. The practical usability of the method is demonstrated by computing the kinetic coefficient of the elements...... Na and Si from first principles. A generalized version of the method may be used for computing the rates of crystal nucleation or other rare events....

  19. Application of cellular mechanisms to growth and development of food producing animals.

    Science.gov (United States)

    Chung, K Y; Johnson, B J

    2008-04-01

    Postnatal skeletal muscle growth is a result of hypertrophy of existing skeletal muscle fibers in food producing animals. Accumulation of additional nuclei, as a source of DNA, to the multinucleated skeletal muscle fiber aids in fiber hypertrophy during periods of rapid skeletal muscle growth. Muscle satellite cells are recognized as the source of nuclei to support muscle hypertrophy. Exogenous growth-enhancing compounds have been used to modulate growth rate and efficiency in meat animals for over a half century. In cattle, these compounds enhance efficiency of growth by preferentially stimulating skeletal muscle growth compared with adipose tissue. There are 2 main classes of compounds approved for use in cattle in the United States, anabolic steroids and beta-adrenergic agonists (beta-AA). Administration of both trenbolone acetate and estradiol-17beta, as implants, increased carcass protein accumulation 8 to 10% in yearling steers. Muscle satellite cells isolated from steers implanted with trenbolone acetate/ estradiol-17beta had a shorter lag phase in culture compared with satellite cells isolated from control steers. Collectively, these data indicate that activation, increased proliferation, and subsequent fusion of satellite cells in muscles of implanted cattle may be an important mechanism by which anabolic steroids enhance muscle hypertrophy. Oral administration of beta-AA to ruminants does not alter DNA accumulation in skeletal muscle over a typical feeding period (28 to 42 d). Enhanced muscle hypertrophy observed due to beta-AA feeding occurs by direct, receptor-mediated changes in protein synthesis and degradation rates of skeletal muscle tissue. Proper timing of anabolic steroid administration when coupled with beta-AA feeding could result in a synergistic response in skeletal muscle growth due to the effects of anabolic steroids at increasing satellite cell activity, which then can support the rapid hypertrophic changes of the muscle fiber when exposed

  20. Exchange-Driven Growth with Birth Rate Less Than Death

    Institute of Scientific and Technical Information of China (English)

    LIN Zhen-Quan; KE Jian-Hong; YE Gao-Xiang

    2005-01-01

    We further study the kinetic behavior of the exchange-driven growth with birth and death for the case of birth rate kernel being less than that of death based on the mean-field theory. The symmetric exchange rate kernel is K(k,j) = K'(k,j) = Ikjv, and the birth and death rates are proportional to the aggregate's size. The long time asymptotic behavior of the aggregate size distribution ak(t) is found to obey a much unusual scaling law with an exponentially growing scaling function φ(x) = exp(x).

  1. Relating Productivity Events to Holocene Bivalve Shell Growth Rates

    Science.gov (United States)

    Huntley, J. W.; Krause, R. A.; Kowalewski, M.; Romanek, C. S.; Kaufman, D. S.; Simoes, M. G.

    2007-12-01

    The growth rate of a bivalve can be influenced by many environmental factors that can change during the life of the organism. In this contribution we present initial data from a millennium scale chronology to assess the relationship between ontogenetic growth in the bivalve Semele casali and paleoenvironmental conditions preserved in the shell using growth increment analysis, radiocarbon-calibrated amino acid racemization dating techniques, stable isotopes (C and O) and high spatial resolution (125-150 samples per cm of shell profile) trace element (Ba, Mn) analysis (LA-ICPMS). Time-averaged specimens of S. casali were dredged from two sites at 10 meters and 30 meters depth along the inner continental shelf at Ubatuba Bay in the Southeast Brazilian Bight, an area influenced by productivity pulses triggered by coastal runoff events and coastal upwelling. Seventy-five individual valves were dated using amino acid racemization (aspartic acid). Dates were calculated using an expanded version of a previously published relationship (Barbour Wood et al., 2006 Quaternary Research 323- 331) between aspartic acid ratios and AMS radiocarbon dates of twelve S. casali individuals from the same sampling locations. The resulting time series has complete coverage for the past three thousand years at centennial resolution. From this time series, a sub-sample of dated valves was selected for more detailed growth increment, stable isotope and high-resolution trace element (Ba/Ca and Mn/Ca) analyses. Oceanic productivity is expressed differentially in the trace element profiles of S. casali with elevated Ba/Ca and Mn/Ca ratios capturing nutrient input through coastal runoff events while elevated Ba/Ca and depressed Mn/Ca ratios represent input through coastal upwelling. Fluctuations in Ba/Ca and Mn/Ca are not correlated to fluctuations in relative growth throughout the ontogeny of an individual bivalve, nor are they expected to be as periods of increased productivity are transient

  2. Scaling laws in the dynamics of crime growth rate

    CERN Document Server

    Alves, Luiz Gustavo de Andrade; Mendes, Renio dos Santos

    2013-01-01

    The increasing number of crimes in areas with large concentrations of people have made cities one of the main source of violence. Understanding characteristics of how crime rate expands and its relations with the cities size goes beyond an academic question, being a central issue for the contemporary society. Here, we characterize and analyze quantitative aspects of murders in the period from 1980 to 2009 in Brazilian cities. We find that the distribution of the annual, biannual and triannual logarithmic homicide growth rates exhibit the same functional form for distinct scales, that is, a scale invariant behaviour. We also identify asymptotic power-law decay relations between the standard deviations of these three growth rates and the initial size. Further, we discuss similarities with complex organizations.

  3. Percieved Relationship between Exchange Rate, Interest Rate and Economic Growth in Nigeria: 1970-2010

    Directory of Open Access Journals (Sweden)

    S. A. J Obansa

    2013-07-01

    Full Text Available This study was specifically embarked upon to establish empirically the relationship exiting among Exchange rate, Interest rate and economic growth in Nigerian economy over the period of 1970-2010. Fundamentally, the period of the study was fractured into two prominent distinctions of economic era - the regulation era and the deregulation era. The study adopted vector auto- regression (VAR technique, with specific emphasis on Impulse Response factor and the Forecast Error Variance Decomposition. The result indicated that Exchange rate had a stronger impact on Economic growth than Interest rate. Particularly, Interest rate impact was found to be positive but however declined as the time horizon increased. It had a little impact on Economic growth in the period of regulation than in the deregulation era. The conclusion arising from the study shows that Exchange rate liberalization was good to Nigerian Economy as it promotes Economic growth. Interest rate liberalization on the other hand does not make an appreciable impact on the Economic growth as it undermines investment drive. The paper therefore recommends that Interest rate liberalization and deregulation should be replaced with the policy of Interest rate regulation as obtained in the 1970s and early 1980s. Normal 0 false false false EN-US X-NONE AR-SA /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; text-align:justify; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin;}

  4. Last Five Years Pakistan Economic Growth Rate GDP And Its Comparison With China India And Bangladesh

    OpenAIRE

    Abdul Rehman; Luan Jingdong; Yuneng Du

    2015-01-01

    Abstract This paper formulates and reviews Pakistans last five years economic growth rate and its comparison with the growth rate of China India and Bangladesh. As growth rate the amount of increment of a specific variable has gained within a specific period of time and context. In fact economic growth rate provides general direction and magnitude of growth for overall economy.

  5. THE INFLUENCE OF THE ECONOMIC GROWTH ON THE BIRTH RATE

    Directory of Open Access Journals (Sweden)

    SAVU MIHAELA

    2013-02-01

    Full Text Available The changes occurred over time in the population have effects on the economy, especially the reductions in thebirth rate which may lead to disturbances in the population structure. The relationship between the economic growthand the birth rate in Romania is analysed over an 11-year period, in order to see its intensity. The presentation of theevolution of the gross domestic product and of the birth rate is completed by the calculation of the Spearmancoefficient for determining the intensity of the relationship between the two indicators. The decrease of the birth rate isdetermined, to a modest extent, by the economic growth, with a wide range of factors that influence it. In this situation,the establishment and implementation of a birth rate recovery strategy is highly necessary to reduce the imbalancecreated in the population structure.

  6. Direct Observation of Aggregative Nanoparticle Growth: Kinetic Modeling of the Size Distribution and Growth Rate

    Energy Technology Data Exchange (ETDEWEB)

    Woehl, Taylor J.; Park, Chiwoo; Evans, James E.; Arslan, Ilke; Ristenpart, William D.; Browning, Nigel D.

    2014-01-08

    Direct observations of solution-phase nanoparticle growth using in situ liquid transmission electron microscopy (TEM) have demonstrated the importance of “non-classical” growth mechanisms, such as aggregation and coalescence, on the growth and final morphology of nanocrystals at the atomic and single nanoparticle scales. To date, groups have quantitatively interpreted the mean growth rate of nanoparticles in terms of the Lifshitz-Slyozov-Wagner (LSW) model for Ostwald ripening, but less attention has been paid to modeling the corresponding particle size distribution. Here we use in situ fluid stage scanning TEM to demonstrate that silver nanoparticles grow by a length-scale dependent mechanism, where individual nanoparticles grow by monomer attachment but ensemble-scale growth is dominated by aggregation. Although our observed mean nanoparticle growth rate is consistent with the LSW model, we show that the corresponding particle size distribution is broader and more symmetric than predicted by LSW. Following direct observations of aggregation, we interpret the ensemble-scale growth using Smoluchowski kinetics and demonstrate that the Smoluchowski model quantitatively captures the mean growth rate and particle size distribution.

  7. A study of the growth rates and growth habits of ice crystals in a solution of antifreeze (glyco) proteins

    Science.gov (United States)

    Li, Qianzhong; Luo, Liaofu

    1996-12-01

    The mechanism of the antifreeze glycoprotein/antifreeze protein interaction on the surface of ice is analyzed. The theory of ice crystal growth in an AF(G)P solution is presented. A quantitative calculation of the growth rates for gain growth has been obtained. The anisotropic growth habits and growth rates of ice crystals in an AF(G)P solution are explained.

  8. The Case for an M2 Growth Rate of 10%

    OpenAIRE

    William Carlson; Conway Lackman

    2013-01-01

    The recovery from the 2008-2009 recession has been much slower than the average recovery since the 1924 recession. As analysts who believe that the St. Louis model created by Leonall Andersen and Jerry Jordan still has relevance we believe that the slow rate of M2 growth since 2Q2009 is a major reason why GDP growth has been so slow. At the 9th Annual Missouri Economics Conference on March 27, 2009 we presented a paper, “Interwar Hoarding, Liquidity Traps, and the 2008 Solvency Trap” in whic...

  9. Bubble growth rate in water binary systems at subatmospheric pressures

    International Nuclear Information System (INIS)

    The vapor-type bubble growth rate has been experimentally studied during bubble boiling both in water and in the following ''positive'' aqueous, binary systems: water-ethanol, water-1-buthanol, water-2-buthanon at pressures between 2 and 26 kPa, the Jackoby numbers between 2700 and 700, and volatile organic component contents between 2 and 30%. Numerical solutions have been presented for growth and annihilation of spherical and axis-symmetrical vapor-type bubbles during transfer between the isometric and isobaric phases. Occurrence of fluctuations both in bubble radius and bubble surface temperature has been predicted

  10. Growth Rate Factor Analysis of Turkey Using Grey System Theory

    OpenAIRE

    Ceviz, Emre; Erden, Caner

    2015-01-01

    In this study, by using Grey System Theory (GST), factors of Gross Domestic Product (GDP) growth rate is analyzed. Macro-economic and financial data in the 2000s is used to evaluate the economic growth of Turkey. GST which can be used with little or inadequate amount of data, was preferred in the analysis. Although discovered in 1982, GST increases the amount of usage and publication especially after the 2000s. The gray system theory in the study focused on the impact on economic analysis. At...

  11. Improvements in plant growth rate using underwater discharge

    International Nuclear Information System (INIS)

    The drainage water from plant pots was irradiated by plasma and then recycled to irrigate plants for improving the growth rate by supplying nutrients to plants and inactivating the bacteria in the bed-soil. Brassica rapa var. perviridis (Chinese cabbage; Brassica campestris) plants were cultivated in pots filled with artificial soil, which included the use of chicken droppings as a fertiliser. The water was recycled once per day from a drainage water pool and added to the bed-soil in the pots. A magnetic compression type pulsed power generator was used to produce underwater discharge with repetition rate of 250 pps. The plasma irradiation times were set as 10 and 20 minutes per day over 28 days of cultivation. The experimental results showed that the growth rate increased significantly with plasma irradiation into the drainage water. The growth rate increased with the plasma irradiation time. The nitrogen concentration of the leaves increased as a result of plasma irradiation based on chlorophyll content analysis. The bacteria in the drainage water were inactivated by the plasma irradiation.

  12. Large-scale parallel lattice Boltzmann-cellular automaton model of two-dimensional dendritic growth

    Science.gov (United States)

    Jelinek, Bohumir; Eshraghi, Mohsen; Felicelli, Sergio; Peters, John F.

    2014-03-01

    An extremely scalable lattice Boltzmann (LB)-cellular automaton (CA) model for simulations of two-dimensional (2D) dendritic solidification under forced convection is presented. The model incorporates effects of phase change, solute diffusion, melt convection, and heat transport. The LB model represents the diffusion, convection, and heat transfer phenomena. The dendrite growth is driven by a difference between actual and equilibrium liquid composition at the solid-liquid interface. The CA technique is deployed to track the new interface cells. The computer program was parallelized using the Message Passing Interface (MPI) technique. Parallel scaling of the algorithm was studied and major scalability bottlenecks were identified. Efficiency loss attributable to the high memory bandwidth requirement of the algorithm was observed when using multiple cores per processor. Parallel writing of the output variables of interest was implemented in the binary Hierarchical Data Format 5 (HDF5) to improve the output performance, and to simplify visualization. Calculations were carried out in single precision arithmetic without significant loss in accuracy, resulting in 50% reduction of memory and computational time requirements. The presented solidification model shows a very good scalability up to centimeter size domains, including more than ten million of dendrites. Catalogue identifier: AEQZ_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEQZ_v1_0.html Program obtainable from: CPC Program Library, Queen’s University, Belfast, UK Licensing provisions: Standard CPC license, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 29,767 No. of bytes in distributed program, including test data, etc.: 3131,367 Distribution format: tar.gz Programming language: Fortran 90. Computer: Linux PC and clusters. Operating system: Linux. Has the code been vectorized or parallelized?: Yes. Program is parallelized using MPI

  13. On oscillatory microstructure during cellular growth of directionally solidified Sn–36at.%Ni peritectic alloy

    Science.gov (United States)

    Peng, Peng; Li, Xinzhong; Li, Jiangong; Su, Yanqing; Guo, Jingjie

    2016-01-01

    An oscillatory microstructure has been observed during deep-cellular growth of directionally solidified Sn–36at.%Ni hyperperitectic alloy containing intermetallic compounds with narrow solubility range. This oscillatory microstructure with a dimension of tens of micrometers has been observed for the first time. The morphology of this wave-like oscillatory structure is similar to secondary dendrite arms, and can be observed only in some local positions of the sample. Through analysis such as successive sectioning of the sample, it can be concluded that this oscillatory microstructure is caused by oscillatory convection of the mushy zone during solidification. And the influence of convection on this oscillatory microstructure was characterized through comparison between experimental and calculations results on the wavelength. Besides, the change in morphology of this oscillatory microstructure has been proved to be caused by peritectic transformation during solidification. Furthermore, the melt concentration increases continuously during solidification of intermetallic compounds with narrow solubility range, which helps formation of this oscillatory microstructure. PMID:27066761

  14. In situ high rate growth of high temperature superconductor tapes

    Energy Technology Data Exchange (ETDEWEB)

    Hammond, M. R. B. (Malcom R. Beasley); Peng, L. S. (Luke S.); Wang, W. (Weizhi); Jo, W.; Ohnishi, T. (Tsuyoshi); Marshall, A. F. (Ann F.); Hammond, R. H. (Robert H.); Beasley, M. R. (Malcom R.); Peterson, E. J. (Eric J.); Ericson, R. (Richard)

    2001-01-01

    In situ high rate growth of YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} superconducting films has been carried out using e-beam deposition. A deposition flux controller is developed to monitor and control the deposition rates using tunable diode laser based atomic absorption. Wide range of temperatures, deposition rates, and oxygen fluxes including atomic and molecular oxygen, as well as ozone, have been explored in order to understand both kinetic and thermodynamic stability. Critical current density above 1 MA/cm{sup 2} has been achieved on SrTiO{sub 3} substrate samples in growth rate up to 75 {angstrom}/sec. Samples prepared on IBAD YSZ/Ni tapes exhibit similar R(T)s and x-ray diffraction patterns. However, critical current densities of the tapes are around kA/cm{sup 2} or lower. The poor critical current density of the tape is attributed to interaction between the YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} film and the YSZ buffer layer.

  15. Salamander growth rates increase along an experimental stream phosphorus gradient.

    Science.gov (United States)

    Bumpers, Phillip M; Maerz, John C; Rosemond, Amy D; Benstead, Jonathan P

    2015-11-01

    Nutrient-driven perturbations to the resource base of food webs are predicted to attenuate with trophic distance, so it is unclear whether higher-level consumers will generally respond to anthropogenic nutrient loading. Few studies have tested whether nutrient (specifically, nitrogen [N] and phosphorus [P]) enrichment of aquatic ecosystems propagates through multiple trophic levels to affect predators, or whether N vs. P is relatively more important in driving effects on food webs. We conducted two-year whole-stream N and P additions to five streams to generate gradients in N and P concentration and N:P ratio (target N:P = 2, 8, 16, 32, 128). Larval salamanders are vertebrate predators of primary and secondary macroinvertebrate consumers in many heterotrophic headwater streams in which the basal resources are detritus and associated microorganisms. We determined the effects of N and P on the growth rates of caged and free-roaming larval Desmognathus quadramaculatus and the average body size of larval Eurycea wilderae. Growth rates and average body size increased by up to 40% and 60%, respectively, with P concentration and were negatively related to N:P ratio. These findings were consistent across both species of salamanders using different methodologies (cage vs. free-roaming) and at different temporal scales (3 months vs. 2 yr). Nitrogen concentration was not significantly related to increased growth rate or body size of the salamander species tested. Our findings suggest that salamander growth responds to the relaxation of ecosystem-level P limitation and that moderate P enrichment can have relatively large effects on vertebrate predators in detritus-based food webs. PMID:27070018

  16. Effects of Electromagnetic Fields of Cellular Phone on Cortisol and Testosterone Hormones Rate in Syrian Hamsters (Mesocricetus auratus

    Directory of Open Access Journals (Sweden)

    A.R. Karami

    2008-01-01

    Full Text Available In this study, the effects of exposure to a 950MHz electromagnetic field (EMF emitted from cellular phones on serum testosterone and cortisol hormones rate of adult male Syrian Hamster were evaluated. Seventy two male Hamster in 3 groups include: group 1 or control group, group 2 or expose for 10 days and under 950 MHz EMF (emitted from Cellular Phone for 1 h daily group 3 or expose for 50 days and under 950 MHz EMF for 1 h daily. In final, blood samples collected for determine of the testosterone and cortisol concentration in the serum. Results showed that in long term exposure EMF (group 3 testosterone and cortisol levels were increased (p<0.01, but both of cortisol and testosterone hormones in short term EMF exposure (group 2 did not significantly change. In conclusion, long-term exposure of cellular phones EMF may affect the reproductive activity and impair endocrine homeostasis and it may cause peripheral effects.

  17. Epstein-Barr virus growth/latency III program alters cellular microRNA expression

    International Nuclear Information System (INIS)

    The Epstein-Barr virus (EBV) is associated with lymphoid and epithelial cancers. Initial EBV infection alters lymphocyte gene expression, inducing cellular proliferation and differentiation as the virus transitions through consecutive latency transcription programs. Cellular microRNAs (miRNAs) are important regulators of signaling pathways and are implicated in carcinogenesis. The extent to which EBV exploits cellular miRNAs is unknown. Using micro-array analysis and quantitative PCR, we demonstrate differential expression of cellular miRNAs in type III versus type I EBV latency including elevated expression of miR-21, miR-23a, miR-24, miR-27a, miR-34a, miR-146a and b, and miR-155. In contrast, miR-28 expression was found to be lower in type III latency. The EBV-mediated regulation of cellular miRNAs may contribute to EBV signaling and associated cancers

  18. Impurity leaching rates of 1000 liter growth tanks

    Energy Technology Data Exchange (ETDEWEB)

    Burnham, A; Floyd, R; Robey, H F; Torres, R

    1999-02-19

    This memo reports on the analysis of some recent measurements of solution impurity levels in the three KDP and one DKDP Pilot Production 1000 liter growth tanks (Tanks B, C, D, & F). Solution samples were taken on a weekly basis during recent crystal growth runs in each tank and were analyzed by inductively coupled plasma emission spectroscopy (ICP-ES). The solution history for five specific elements, Si, B, Al, Fe and Ca will be analyzed in detail. The first four of these elements are input into solution via slow dissolution of the glass vessel at a rate which is strongly dependent on the solution temperature. Si and B continuously accumulate in solution, since they are not incorporated into the crystal. Al and Fe by comparison are incorporated into the crystal (primarily the prismatic sectors) and present problems to inclusion-free growth (Al) and 30 damage (Fe). The level of these impurities initially increases when the crystal size is small but later decreases when the rate of incorporation into the crystal exceeds the rate of dissolution of the glass tank. The last element, Ca is of interest since it has recently been observed to be one of the elements found at the location of 3cu damage. For Si and B, the dissolution or leach rate from the glass tank is easily obtained from the results of the chemical analysis. The temperature dependent leach rates are shown to be comparable (within a factor of two) for all four tanks, with Tank B (DKDP) having the lowest rate of Si accumulation. The glass leach rates of the two incorporating elements Al and Fe require substantially more analysis as the daily variation of the crystal dimensions, the solution concentration, and the mass of KDP remaining in solution must be taken into account in order to separate the rate of impurity incorporation from the rate of dissolution of the glass. The method for accomplishing this separation is described, and the result obtained is that the leach rates of all four tanks are within a

  19. Effects of sulfur chemistry and flow rate on fatigue crack growth rates in LWR environments

    International Nuclear Information System (INIS)

    Fatigue crack growth rate tests, at a load ratio of 0.2, have been conducted on steels of low, medium and high sulfur contents (0.004%, 0.013% and 0.025%) in PWR water at both low and high flow rates. Crack growth rates show no dependence on flow rate, but are strongly dependent on sulfur content, with a large proportion of environmental assistance for the highest sulfur contents. Tests of low and high sulfur content steels at a load ratio of 0.7 show relatively little environmental assistance in either case. The fractography of these specimens shows the usual brittle appearance for environmentally-assisted fatigue crack growth. In addition, the opposing fracture surfaces match perfectly, indicating that little or no dissolution of the metal matrix has occurred, and there is very little plastic flow associated with the fatigue cracking process. The x-ray photoelectron emission examination of the fracture surface oxides shows that FeS and FeS2 coexist in the oxide layer, suggesting that the conditions within the crack enclave involved near-neutral pH and cathodic potentials

  20. On the growth rate of leaf-wise intersections

    CERN Document Server

    Macarini, Leonardo; Paternain, Gabriel P

    2011-01-01

    We define a new variant of Rabinowitz Floer homology that is particularly well suited to studying the growth rate of leaf-wise intersections. We prove that for closed manifolds $M$ whose loop space is "complicated", if $\\Sigma$ is a non-degenerate fibrewise starshaped hypersurface in $T^*M$ and $\\phi$ is a generic Hamiltonian diffeomorphism then the number of leaf-wise intersection points of $\\phi$ in $\\Sigma$ grows exponentially in time. Concrete examples of such manifolds $M$ are the connected sum of two copies of $S^2 \\times S^2$, the connected sum of $T^4$ and $CP^2$, or any surface of genus greater than one.

  1. The effects of accelerated growth rates and estrogen implants in prepubertal Holstein heifers on growth, feed efficiency, and blood parameters.

    Science.gov (United States)

    Lammers, B P; Heinrichs, A J; Kensinger, R S

    1999-08-01

    Sixty-eight Holstein heifers were used to determine the effects of accelerated growth rates by increased nutrient intake and estrogen implants on feed efficiency, structural growth, and blood parameters in heifers between 19 and 39 wk of age. At the beginning of the treatment period, the heifers were assigned to one of four treatment groups by using a randomized complete block design in a 2 x 2 factorial arrangement. The treatments were standard growth rate (700 g/d), accelerated growth rate (1000 g/d), standard growth rate with an estradiol implant, and accelerated growth rate with an estradiol implant. All heifers received the same diet, but dry matter intake was adjusted weekly to achieve the target rate of gain. Accelerating heifer growth rates from 705 to 1007 g/d improved feed efficiency 5.1%, increased the rate of withers height, heart girth, and hip width growth 12, 27, and 27%, respectively, and body condition scores 0.25 points. Estradiol implants improved feed efficiency 2.4% and decreased the rate of withers height 6% and heart girth growth 3.5%. Increased nutrient intake and average daily gain depressed mean plasma growth hormone and urea nitrogen content 17 and 7%, respectively, while elevating insulin-like growth factor-1 levels by 10%. Estradiol implants increased mean plasma growth hormone content by 29% and insulin-like growth factor-1 levels by 17%, but decreased urea nitrogen content by 11%. Feeding prepubertal heifers for accelerated growth rates increased structural growth with a small increase in body condition, whereas estradiol implants improved feed efficiency and decreased the growth rate of withers height and heart girth without affecting the rate of hip width growth. PMID:10480101

  2. Flux imbalance analysis and the sensitivity of cellular growth to changes in metabolite pools.

    Directory of Open Access Journals (Sweden)

    Ed Reznik

    Full Text Available Stoichiometric models of metabolism, such as flux balance analysis (FBA, are classically applied to predicting steady state rates - or fluxes - of metabolic reactions in genome-scale metabolic networks. Here we revisit the central assumption of FBA, i.e. that intracellular metabolites are at steady state, and show that deviations from flux balance (i.e. flux imbalances are informative of some features of in vivo metabolite concentrations. Mathematically, the sensitivity of FBA to these flux imbalances is captured by a native feature of linear optimization, the dual problem, and its corresponding variables, known as shadow prices. First, using recently published data on chemostat growth of Saccharomyces cerevisae under different nutrient limitations, we show that shadow prices anticorrelate with experimentally measured degrees of growth limitation of intracellular metabolites. We next hypothesize that metabolites which are limiting for growth (and thus have very negative shadow price cannot vary dramatically in an uncontrolled way, and must respond rapidly to perturbations. Using a collection of published datasets monitoring the time-dependent metabolomic response of Escherichia coli to carbon and nitrogen perturbations, we test this hypothesis and find that metabolites with negative shadow price indeed show lower temporal variation following a perturbation than metabolites with zero shadow price. Finally, we illustrate the broader applicability of flux imbalance analysis to other constraint-based methods. In particular, we explore the biological significance of shadow prices in a constraint-based method for integrating gene expression data with a stoichiometric model. In this case, shadow prices point to metabolites that should rise or drop in concentration in order to increase consistency between flux predictions and gene expression data. In general, these results suggest that the sensitivity of metabolic optima to violations of the steady

  3. Cellular mechanisms of arrhythmias: from rate-dependent APD variations to heterocellular coupling

    OpenAIRE

    Salvarani, Nicolò

    2008-01-01

    It is well established that a variety of pathological conditions induces structural and electrical remodeling of the heart which can lead to heart failure and cardiac arrhythmias. Clinically, structural remodeling is characterized by changes in the shape, size and function of the heart. These changes are based on diverse and complex cellular reactions to injury and involve both cardiomyocytes and non-cardiomyocytes. Histopathologically, remodeling typically involves cardiomyocyte hypertrophy,...

  4. Tractable Model for Rate in Self-Backhauled Millimeter Wave Cellular Networks

    OpenAIRE

    Singh, Sarabjot; Kulkarni, Mandar N.; Ghosh, Amitava; Andrews, Jeffrey G.

    2014-01-01

    Millimeter wave (mmW) cellular systems will require high gain directional antennas and dense base station (BS) deployments to overcome high near field path loss and poor diffraction. As a desirable side effect, high gain antennas provide interference isolation, providing an opportunity to incorporate self-backhauling--BSs backhauling among themselves in a mesh architecture without significant loss in throughput--to enable the requisite large BS densities. The use of directional antennas and r...

  5. Joint Time-Domain Resource Partitioning, Rate Allocation, and Video Quality Adaptation in Heterogeneous Cellular Networks

    OpenAIRE

    Argyriou, Antonios; Kosmanos, Dimitrios; Tassiulas, Leandros

    2015-01-01

    Heterogenous cellular networks (HCN) introduce small cells within the transmission range of a macrocell. For the efficient operation of HCNs it is essential that the high power macrocell shuts off its transmissions for an appropriate amount of time in order for the low power small cells to transmit. This is a mechanism that allows time-domain resource partitioning (TDRP) and is critical to be optimized for maximizing the throughput of the complete HCN. In this paper, we investigate video comm...

  6. Multilayer Coating of Tetrandrine-loaded PLGA nanoparticles: Effect of surface charges on cellular uptake rate and drug release profile.

    Science.gov (United States)

    Meng, Rui; Li, Ke; Chen, Zhe; Shi, Chen

    2016-02-01

    The effect of surface charges on the cellular uptake rate and drug release profile of tetrandrine-loaded poly(lactic-co-glycolic acid) (PLGA) nanoparticles (TPNs) was studied. Stabilizer-free nanoprecipitation method was used in this study for the synthesis of TPNs. A typical layer-by-layer approach was applied for multi-coating particles' surface with use of poly(styrene sulfonate) sodium salt (PSS) as anionic layer and poly(allylamine hydrochloride) (PAH) as cationic layer. The modified TPNs were characterized by different physicochemical techniques such as Zeta sizer, scanning electron microscopy and transmission electron microscopy. The drug loading efficiency, release profile and cellular uptake rate were evaluated by high performance liquid chromatography and confocal laser scanning microscopy, respectively. The resultant PSS/PAH/PSS/PAH/TPNs (4 layers) exhibited spherical-shaped morphology with the average size of 160.3±5.165 nm and zeta potential of-57.8 mV. The encapsulation efficiency and drug loading efficiency were 57.88% and 1.73%, respectively. Multi-layer coating of polymeric materials with different charges on particles' surface could dramatically influence the drug release profile of TPNs (4 layers vs. 3 layers). In addition, variable layers of surface coating could also greatly affect the cellular uptake rate of TPNs in A549 cells within 8 h. Overall, by coating particles' surface with those different charged polymers, precise control of drug release as well as cellular uptake rate can be achieved simultaneously. Thus, this approach provides a new strategy for controllable drug delivery. PMID:26838734

  7. Relationship between maternal distress with fetus growth rate: mediator role of heart rate

    OpenAIRE

    2009-01-01

    The aim of present investigation was to study the relationship between mothers` distress and fetal growth. In this correlational study, 110 pregnant women selected randomly and completed Depression Anxiety Stress Scale (DASS) before ultrasound measurement of fetus. The results of structural equation model have shown that the overall model has been accepted (χ2 = 36.4, df = 24, p>0.05). In fact, by increasing mothers` stress and anxiety, the fetus heart rate was increased and it decreased the ...

  8. Standard test method for measurement of fatigue crack growth rates

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2008-01-01

    1.1 This test method covers the determination of fatigue crack growth rates from near-threshold to Kmax controlled instability. Results are expressed in terms of the crack-tip stress-intensity factor range (ΔK), defined by the theory of linear elasticity. 1.2 Several different test procedures are provided, the optimum test procedure being primarily dependent on the magnitude of the fatigue crack growth rate to be measured. 1.3 Materials that can be tested by this test method are not limited by thickness or by strength so long as specimens are of sufficient thickness to preclude buckling and of sufficient planar size to remain predominantly elastic during testing. 1.4 A range of specimen sizes with proportional planar dimensions is provided, but size is variable to be adjusted for yield strength and applied force. Specimen thickness may be varied independent of planar size. 1.5 The details of the various specimens and test configurations are shown in Annex A1-Annex A3. Specimen configurations other than t...

  9. Perspectives on massive coral growth rates in a changing ocean.

    Science.gov (United States)

    Lough, Janice M; Cantin, Neal E

    2014-06-01

    The tropical ocean environment is changing at an unprecedented rate, with warming and severe tropical cyclones creating obvious impacts to coral reefs within the last few decades and projections of acidification raising concerns for the future of these iconic and economically important ecosystems. Documenting variability and detecting change in global and regional climate relies upon high-quality observational records of climate variables supplemented, prior to the mid-19th century, with reconstructions from various sources of proxy climate information. Here we review how annual density banding patterns that are recorded in the skeletons of massive reef-building corals have been used to document environmental change and impacts within coral reefs. Massive corals provide a historical perspective of continuous calcification processes that pre-date most ecological observations of coral reefs. High-density stress bands, abrupt declines in annual linear extension, and evidence of partial mortality within the skeletal growth record reveal signatures of catastrophic stress events that have recently been attributed to mass bleaching events caused by unprecedented thermal stress. Comparison of recent trends in annual calcification with century-scale baseline calcification rates reveals that the frequency of growth anomalies has increased since the late 1990s throughout most of the world's coral reef ecosystems. Continuous coral growth histories provide valuable retrospective information on the coral response to environmental change and the consequences of anthropogenic climate change. Co-ordinated efforts to synthesize and combine global calcification histories will greatly enhance our understanding of current calcification responses to a changing ocean. PMID:25070864

  10. Cellular Localization of the Molecular Forms of Acetylcholinesterase in rat Pheochromocytoma Pc12 Cells Treated with Nerve Growth Factor1

    OpenAIRE

    Inestrosa, Nibaldo C; Reiness, C. Gary; Reichardt, Louis F.; Hall, Zach W

    1981-01-01

    In rat pheochromocytoma (PC12) cells treated with nerve growth factor (NGF), there are several molecular forms of the enzyme acetylcholinesterase (AChE) which sediment on sucrose density gradients at 4 to 6, 10, and 16 S, respectively. We have investigated the cellular localization of these forms in PC12 cells. In order to determine which forms are soluble and which are membrane bound, we extracted PC12 cells in buffers of various ionic strengths and detergent compositions. To distinguish int...

  11. Cellular growth and survival are mediated by beta 1 integrins in normal human breast epithelium but not in breast carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Howlett, Anthony R; Bailey, Nina; Damsky, Caroline; Petersen, Ole W; Bissell, Mina J

    1994-11-28

    We previously established a rapid three-dimensional assay for discrimination of normal and malignant human breast epithelial cells using a laminin-rich reconstituted basement membrane. In this assay, normal epithelial cells differentiate into well-organized acinar structures whereas tumor cells fail to recapitulate this process and produce large, disordered colonies. The data suggest that breast acinar morphogenesis and differentiation is regulated by cell-extracellular matrix (ECM) interactions and that these interactions are altered in malignancy. Here, we investigated the role of ECM receptors (integrins) in these processes and report on the expression and function of potential laminin receptors in normal and tumorigenic breast epithelial cells. Immmunocytochemical analysis showed that normal and carcinoma cells in a three-dimensional substratum express profiles of integrins similar to normal and malignant breast tissues in situ. Normal cells express {alpha}1, {alpha}2, {alpha}3, {alpha}6, {beta}1 and {beta}4 integrin subunits, whereas breast carcinoma cells show variable losses, disordered expression, or down regulation of these subunits. Function-blocking experiments using inhibitory antiintegrin subunit antibodies showed a >5-fold inhibition of the formation of acinar structures by normal cells in the presence of either anti-{beta}1 or anti-{alpha}3 antibodies, whereas anti-{alpha}2 or -{alpha}6 had little or no effect. In experiments where collagen type I gels were used instead of basement membrane, acinar morphogenesis was blocked by anti-{beta}1 and -{alpha}2 antibodies but not by anti-{alpha}3. These data suggest a specificity of integrin utilization dependent on the ECM ligands encountered by the cell. The interruption of normal acinar morphogenesis by anti-integrin antibodies was associated with an inhibition of cell growth and induction of apoptosis. Function-blocking antibodies had no inhibitory effect on the rate of tumor cell growth, survival or

  12. Effects of UV-A Radiation on Desmodesmus armatus: Changes in Growth Rate, Pigment Content and Morphological Appearance

    Science.gov (United States)

    Pálffy, Károly; Vörös, Lajos

    2006-10-01

    Laboratory cultures of Desmodesmus armatus (R. Chod.) Hegew. were grown under different levels of photosynthetically active radiation (PAR) supplemented with 3.75 mW . cm-2 UV-A radiation. Growth rate was monitored daily, chlorophyl-a concentration, total carotenoid content, cell number and the relative abundance of different coenobial forms was determined at the end of each experiment. Exposure to UV-A radiation resulted in an increasing inhibition of growth towards higher PAR levels, reaching 100% at 400 μmol . m-2 . s-1. Cellular carotenoid content was higher in the presence of UV-A radiation, on the other hand no differences were observed in cellular chlorophyll-a concentration. UV-A radiation also induced changes in coenobium formation with a decreasing proportion of 4-celled coenobia and an increase in the abundance of 2-celled and teratologic coenobia, suggesting that high intensity UV-A radiation may influence cell cycle events or morphology development.

  13. Growth rate controlled barium partitioning in calcite and aragonite

    Science.gov (United States)

    Goetschl, Katja Elisabeth; Mavromatis, Vasileios; Baldermann, Andre; Purgstaller, Bettina; Dietzel, Martin

    2016-04-01

    The barium (Ba) content and the Ba/Ca molar ratios in biogenic and abiotic carbonates have been widely used from the scientific community as a geochemical proxy especially in marine and early diagenetic settings. The Ba content of carbonate minerals has been earlier associated to changes in oceanic circulation that may have been caused by upwelling, changes in weathering regimes and river-runoff as well as melt water discharge. The physicochemical controls of Ba ion incorporation in the two most abundant CaCO3 polymorphs found in Earth's surface environments, i.e. calcite and aragonite, have adequately been studied only for calcite. These earlier studies (i.e. [1]) suggest that at increasing growth rate, Ba partitioning in calcite is increasing as well. In contrast, to date the effect of growth rate on the partitioning of Ba in aragonite remains questionable, despite the fact that this mineral phase is the predominant carbonate-forming polymorph in shallow marine environments. To shed light on the mechanisms controlling Ba ion uptake in carbonates in this study we performed steady-state Ba co-precipitation experiments with calcite and aragonite at 25°C. The obtained results for the partitioning of Ba in calcite are in good agreement with those reported earlier by [1], whereas those for aragonite indicate a reduction of Ba partitioning at elevated aragonite growth rates, with the partitioning coefficient value between solid and fluid to be approaching the unity. This finding is good agreement with the formation of a solid solution in the aragonite-witherite system, owing to the isostructural crystallography of the two mineral phases. Moreover, our data set provides new insights that are required for reconstructing the evolution of the Ba content of pristine marine versus diagenetically altered carbonate minerals commonly occurring in marine subfloor settings, as the thermodynamically less stable aragonite will transform to calcite enriched in Ba, whilst affecting

  14. Inter-cellular nanovesicle mediated microRNA transfer: a mechanism of environmental modulation of hepatocellular cancer cell growth

    Science.gov (United States)

    Kogure, Takayuki; Lin, Wen-Lang; Yan, Irene K.; Braconi, Chiara; Patel, Tushar

    2011-01-01

    Hepatocellular carcinoma (HCC) is characterized by a propensity for multifocality, growth by local spread, and dysregulation of multiple signaling pathways. These features may be determined by the tumoral microenvironment. The potential of tumor cells to modulate HCC growth and behavior by secreted proteins has been extensively studied. In contrast the potential for genetic modulation is poorly understood. We investigated the role and involvement of tumor derived nanovesicles capable of altering gene expression, and characterized their ability to modulate cell signaling and biological effects in other cells. We show that HCC cells can produce nanovesicles, exosomes, that differ in both RNA and protein content from their cells of origin. These can be taken up and internalized by other cells, and can transmit a functional transgene. The microRNA content of these exosomes was examined, and a subset that is highly enriched within exosomes was identified. A combinatorial approach to identify potential targets identified transforming growth factor β activated kinase-1 (TAK1) as the most likely candidate pathway that could be modulated by these miRNA. Loss of TAK1 has been implicated in hepatocarcinogenesis and is a biologically plausible target for inter-cellular modulation. We showed that HCC cell derived exosomes can modulate TAK1 expression and associated signaling and enhance transformed cell growth in recipient cells. Conclusion: Exosome mediated miRNA transfer is an important mechanism of inter-cellular communication in HCC cells. These observations identify a unique inter-cellular mechanism that could potentially contribute to local spread, intrahepatic metastases or multifocal growth in HCC. PMID:21721029

  15. Biochemical composition of Rhodomonas baltica as a function of the dilution rate during steady rate of growth

    OpenAIRE

    Le, Hoang Bao Chau

    2013-01-01

    The algae Rhodomonas baltica, Karsten was cultured in Guillard f-medium with the phosphate concentration reduced to 5 µmol/L. The cultures were diluted at seven different dilution rates corresponding approximately to growth rates of 40, 50, 60, 70, 80, 90 and 100% of µmax measured in batch culture. The biochemical composition of the algae was measured for variable specific growth rate in cultures maintained in steady state of growth. The main objective of the thesis was to study the...

  16. Does seed mass drive the differences in relative growth rate between growth forms?

    Science.gov (United States)

    Houghton, Jennie; Thompson, Ken; Rees, Mark

    2013-07-01

    The idea that herbaceous plants have higher relative growth rates (RGRs) compared with woody plants is fundamental to many of the most influential theories in plant ecology. This difference in growth rate is thought to reflect systematic variation in physiology, allocation and leaf construction. Previous studies documenting this effect have, however, ignored differences in seed mass. As woody species often have larger seeds and RGR is negatively correlated with seed mass, it is entirely possible the lower RGRs observed in woody species is a consequence of having larger seeds rather than different growth strategies. Using a synthesis of the published literature, we explored the relationship between RGR and growth form, accounting for the effects of seed mass and study-specific effects (e.g. duration of study and pot volume), using a mixed-effects model. The model showed that herbaceous species do indeed have higher RGRs than woody species, and that the difference was independent of seed mass, thus at all seed masses, herbaceous species on average grow faster than woody ones. PMID:23677351

  17. Reproductive value, the stable stage distribution, and the sensitivity of the population growth rate to changes in vital rates

    Directory of Open Access Journals (Sweden)

    Hal Caswell

    2010-09-01

    Full Text Available The population growth rate, or intrinsic rate of increase, measures the potential rate of growth of a population with specified and fixed vital rates.The sensitivity of population growth rate to changes in the vital rates can be written in terms of the stable stage or age distribution and the reproductive value distribution. If the vital rate measures the rate of production of one type of individual by another, then the sensitivity of growth rate is proportional to the reproductive value of the destination type and the representation in the stable stage distribution of the source type. This formal relationship exists in three forms: one limited to age-classified populations, a second that applies to stage- or age-classified populations, and a third that uses matrix calculus. Each uses a different set of formal demographic techniques; together they provide a relationship that beautifully cuts across different types of demographic models.

  18. Rating Growth of Scientific Knowledge and Risk from Theory Bubbles

    CERN Document Server

    Loeb, Abraham

    2011-01-01

    In physics the value of a theory is measured by its agreement with experimental data. But how should the physics community gauge the value of an emerging theory that has not been tested experimentally as of yet? With no reality check, a hypothesis like string theory may linger for a while before physicists will know its actual value in describing nature. In this short article, I advocate the need for a website operated by graduate students that will use various measures of publicly available data (such as the growth rate of newly funded experiments, research grants, publications, and faculty jobs) to gauge the future dividends of various research frontiers. The analysis can benefit from past experience (e.g. in research areas that suffered from limited experimental data over long periods of time) and aim to alert the community of the risk from future theory bubbles.

  19. Growth rate inhibition of phytopathogenic fungi by characterized chitosans

    Directory of Open Access Journals (Sweden)

    Enio N. Oliveira Junior

    2012-06-01

    Full Text Available The inhibitory effects of fifteen chitosans with different degrees of polymerization (DP and different degrees of acetylation (F A on the growth rates (GR of four phytopathogenic fungi (Alternaria alternata, Botrytis cinerea, Penicillium expansum, and Rhizopus stolonifer were examined using a 96-well microtiter plate and a microplate reader. The minimum inhibitory concentrations (MICs of the chitosans ranged from 100 µg × mL-1 to 1,000 µg × mL-1 depending on the fungus tested and the DP and F A of the chitosan. The antifungal activity of the chitosans increased with decreasing F A. Chitosans with low F A and high DP showed the highest inhibitory activity against all four fungi. P. expansum and B. cinerea were relatively less susceptible while A. alternata and R. stolonifer were relatively more sensitive to the chitosan polymers. Scanning electron microscopy of fungi grown on culture media amended with chitosan revealed morphological changes.

  20. International co-operative group on cyclic crack growth rate

    International Nuclear Information System (INIS)

    The International Cyclic Crack Growth Group was formed in 1977 with the general objective to co-ordinate research and development efforts on corrosion fatigue on pressure boundary materials in light water reactor service environments. Three co-operative programs have been agreed. The first was on data reduction methods. The same raw data were given to the members and the derived curves of dα/dN, as a function of ΔK, obtained, were then compared. Many discrepancies were observed at the first attempt but comparison and discussion enabled the participants to reach a good agreement. The second was a Round-Robin experiment on pressure vessel steel in a water environment at 2880C. The results were most interesting and an understanding of the discrepancies observed was achieved. The third program is Round-Robin tests on pressure vessel steel specimens in simulated BWR and PWR environments at high R ratios. The aim of this co-operative work is to develop a sufficient understanding of the mechanisms controlling the rate of crack growth to enable all the data generated in different laboratories to be used by the international technical community with confidence as truly representative of typical LWR operational conditions. (author)

  1. Aerosol observations and growth rates in the tropical tropopause layer

    Directory of Open Access Journals (Sweden)

    D. A. Waddicor

    2012-01-01

    Full Text Available We present a case study of Aitken and accumulation mode aerosol observed downwind of the anvils of deep tropical thunderstorms. The measurements were made by condensation nuclei counters flown on the Egrett high-altitude aircraft from Darwin during the ACTIVE campaign, in monsoon conditions producing widespread convection over land and ocean. Maximum measured concentrations of aerosol in the size range 10–100 nm were 25 000 cm−3 STP. By calculating back-trajectories from the observations, and projecting on to infrared satellite images, the time since the air exited cloud was estimated. In this way a time scale of ~ 3–4 h was derived for the 10–100 nm aerosol concentration to reach its peak. We examine the hypothesis that the growth in aerosol concentrations can be explained by production of sulphuric acid from SO2 followed by particle nucleation and coagulation. Estimates of the sulphuric acid production rate show that the observations are only consistent with this hypothesis if the particles coagulate to sizes > 10 nm much more quickly than is suggested by current theory. Alternatively, other condensible gases (possibly organic drive the growth of aerosol particles in the TTL.

  2. Error Growth Rate in the MM5 Model

    Science.gov (United States)

    Ivanov, S.; Palamarchuk, J.

    2006-12-01

    The goal of this work is to estimate model error growth rates in simulations of the atmospheric circulation by the MM5 model all the way from the short range to the medium range and beyond. The major topics are addressed to: (i) search the optimal set of parameterization schemes; (ii) evaluate the spatial structure and scales of the model error for various atmospheric fields; (iii) determine geographical regions where model errors are largest; (iv) define particular atmospheric patterns contributing to the fast and significant model error growth. Results are presented for geopotential, temperature, relative humidity and horizontal wind components fields on standard surfaces over the Atlantic-European region during winter 2002. Various combinations of parameterization schemes for cumulus, PBL, moisture and radiation are used to identify which one provides a lesser difference between the model state and analysis. The comparison of the model fields is carried out versus ERA-40 reanalysis of the ECMWF. Results show that the rate, at which the model error grows as well as its magnitude, varies depending on the forecast range, atmospheric variable and level. The typical spatial scale and structure of the model error also depends on the particular atmospheric variable. The distribution of the model error over the domain can be separated in two parts: the steady and transient. The first part is associated with a few high mountain regions including Greenland, where model error is larger. The transient model error mainly moves along with areas of high gradients in the atmospheric flow. Acknowledgement: This study has been supported by NATO Science for Peace grant #981044. The MM5 modelling system used in this study has been provided by UCAR. ERA-40 re-analysis data have been obtained from the ECMWF data server.

  3. Pichia pastoris Exhibits High Viability and a Low Maintenance Energy Requirement at Near-Zero Specific Growth Rates

    Science.gov (United States)

    Rebnegger, Corinna; Vos, Tim; Graf, Alexandra B.; Valli, Minoska; Pronk, Jack T.

    2016-01-01

    ABSTRACT The yeast Pichia pastoris is a widely used host for recombinant protein production. Understanding its physiology at extremely low growth rates is a first step in the direction of decoupling product formation from cellular growth and therefore of biotechnological relevance. Retentostat cultivation is an excellent tool for studying microbes at extremely low specific growth rates but has so far not been implemented for P. pastoris. Retentostat feeding regimes were based on the maintenance energy requirement (mS) and maximum biomass yield on glucose (YX/Smax) estimated from steady-state glucose-limited chemostat cultures. Aerobic retentostat cultivation enabled reproducible, smooth transitions from a specific growth rate (μ) of 0.025 h−1 to near-zero specific growth rates (μ cultivation. Transcriptional reprogramming toward zero growth included the upregulation of many transcription factors as well as stress-related genes and the downregulation of cell cycle genes. This study underlines the relevance of comparative analysis of maintenance energy metabolism, which has an important impact on large-scale industrial processes. IMPORTANCE The yeast Pichia pastoris naturally lives on trees and can utilize different carbon sources, among them glucose, glycerol, and methanol. In biotechnology, it is widely used for the production of recombinant proteins. For both the understanding of life in its natural habitat and optimized production processes, a better understanding of cell physiology at an extremely low growth rate would be of extraordinary value. Therefore, we have grown P. pastoris in a retentostat, which allows the cultivation of metabolically active cells even at zero growth. Here we reached doubling times as long as 38 days and found that P. pastoris decreases its maintenance energy demand 3-fold during very slow growth, which enables it to survive with a much lower substrate supply than baker's yeast. PMID:27208115

  4. Small regulatory RNA-induced growth rate heterogeneity of Bacillus subtilis.

    Science.gov (United States)

    Mars, Ruben A T; Nicolas, Pierre; Ciccolini, Mariano; Reilman, Ewoud; Reder, Alexander; Schaffer, Marc; Mäder, Ulrike; Völker, Uwe; van Dijl, Jan Maarten; Denham, Emma L

    2015-03-01

    Isogenic bacterial populations can consist of cells displaying heterogeneous physiological traits. Small regulatory RNAs (sRNAs) could affect this heterogeneity since they act by fine-tuning mRNA or protein levels to coordinate the appropriate cellular behavior. Here we show that the sRNA RnaC/S1022 from the Gram-positive bacterium Bacillus subtilis can suppress exponential growth by modulation of the transcriptional regulator AbrB. Specifically, the post-transcriptional abrB-RnaC/S1022 interaction allows B. subtilis to increase the cell-to-cell variation in AbrB protein levels, despite strong negative autoregulation of the abrB promoter. This behavior is consistent with existing mathematical models of sRNA action, thus suggesting that induction of protein expression noise could be a new general aspect of sRNA regulation. Importantly, we show that the sRNA-induced diversity in AbrB levels generates heterogeneity in growth rates during the exponential growth phase. Based on these findings, we hypothesize that the resulting subpopulations of fast- and slow-growing B. subtilis cells reflect a bet-hedging strategy for enhanced survival of unfavorable conditions. PMID:25790031

  5. Small regulatory RNA-induced growth rate heterogeneity of Bacillus subtilis.

    Directory of Open Access Journals (Sweden)

    Ruben A T Mars

    2015-03-01

    Full Text Available Isogenic bacterial populations can consist of cells displaying heterogeneous physiological traits. Small regulatory RNAs (sRNAs could affect this heterogeneity since they act by fine-tuning mRNA or protein levels to coordinate the appropriate cellular behavior. Here we show that the sRNA RnaC/S1022 from the Gram-positive bacterium Bacillus subtilis can suppress exponential growth by modulation of the transcriptional regulator AbrB. Specifically, the post-transcriptional abrB-RnaC/S1022 interaction allows B. subtilis to increase the cell-to-cell variation in AbrB protein levels, despite strong negative autoregulation of the abrB promoter. This behavior is consistent with existing mathematical models of sRNA action, thus suggesting that induction of protein expression noise could be a new general aspect of sRNA regulation. Importantly, we show that the sRNA-induced diversity in AbrB levels generates heterogeneity in growth rates during the exponential growth phase. Based on these findings, we hypothesize that the resulting subpopulations of fast- and slow-growing B. subtilis cells reflect a bet-hedging strategy for enhanced survival of unfavorable conditions.

  6. INFLUENCE OF DOSE RATE ON THE CELLULAR RESPONSE TO LOW- AND HIGH-LET RADIATIONS

    Directory of Open Access Journals (Sweden)

    Anne-Sophie eWozny

    2016-03-01

    Full Text Available Nowadays, head and neck squamous cell carcinoma (HNSCC treatment failure is mostly explained by loco-regional progression or intrinsic radioresistance. Radiotherapy has recently evolved with the emergence of heavy ion radiations or new fractionation schemes of photon therapy which modify the dose-rate of treatment delivery. The aim of the present study was then to evaluate the in vitro influence of a dose rate variation during conventional radiotherapy or carbon ion hadrontherapy treatment in order to improve the therapeutic care of patient. In this regard, two HNSCC cell lines were irradiated with photons or 72MeV/n carbon ions at a dose rate of 0.5, 2 or 10Gy/min.For both radiosensitive and radioresistant cells, the change in dose rate significantly affected cell survival in response to photon exposure, this variation of radiosensitivity was associated to the number of initial and residual DNA double-strand breaks. By contrast, the dose rate change did not affect neither cell survival nor the residual DNA double-strand breaks after carbon ion irradiation. As a result, the Relative Biological Efficiency at 10% survival increased when the dose rate decreased.In conclusion, in the radiotherapy treatment of HNSCC, it is advised to remain very careful when modifying the classical schemes towards altered-fractionation. At the opposite, as the dose rate does not seem to have any effects after carbon ion exposure, there is less need to adapt hadrontherapy treatment planning during active system irradiation

  7. Cellular growth defects triggered by an overload of protein localization processes.

    Science.gov (United States)

    Kintaka, Reiko; Makanae, Koji; Moriya, Hisao

    2016-01-01

    High-level expression of a protein localized to an intracellular compartment is expected to cause cellular defects because it overloads localization processes. However, overloads of localization processes have never been studied systematically. Here, we show that the expression levels of green fluorescent proteins (GFPs) with localization signals were limited to the same degree as a toxic misfolded GFP in budding yeast cells, and that their high-level expression caused cellular defects associated with localization processes. We further show that limitation of the exportin Crm1 determined the expression limit of GFP with a nuclear export signal. Although misfolding of GFP with a vesicle-mediated transport signal triggered endoplasmic reticulum stress, it was not the primary determinant of its expression limit. The precursor of GFP with a mitochondrial targeting signal caused a cellular defect. Finally, we estimated the residual capacities of localization processes. High-level expression of a localized protein thus causes cellular defects by overloading the capacities of localization processes. PMID:27538565

  8. Maximizing the Sum Rate in Cellular Networks Using Multi-Convex Optimization

    OpenAIRE

    Al-Shatri, Hussein; LI Xiang; Ganesan, Rakash SivaSiva; Klein, Anja; Weber, Tobias

    2015-01-01

    In this paper, we propose a novel algorithm to maximize the sum rate in interference-limited scenarios where each user decodes its own message with the presence of unknown interferences and noise considering the signal-to-interference-plus-noise-ratio. It is known that the problem of adapting the transmit and receive filters of the users to maximize the sum rate with a sum transmit power constraint is non-convex. Our novel approach is to formulate the sum rate maximization problem as an equiv...

  9. Growth-rate regulated genes have profound impact on interpretation of transcriptome profiling in Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Regenberg, Birgitte; Grotkjaer, Thomas; Winther, Ole;

    2006-01-01

    Growth rate is central to the development of cells in all organisms. However, little is known about the impact of changing growth rates. We used continuous cultures to control growth rate and studied the transcriptional program of the model eukaryote Saccharomyces cerevisiae, with generation times...

  10. Growth inhibition of Streptococcus mutans by cellular extracts of human intestinal lactic acid bacteria.

    OpenAIRE

    Ishihara, K; Miyakawa, H; Hasegawa, A.; Takazoe, I; Kawai, Y.

    1985-01-01

    The in vitro growth of Streptococcus mutans was completely inhibited by water-soluble extracts from cells of various intestinal lactic acid bacteria identified as Streptococcus faecium, Streptococcus equinus, Lactobacillus fermentum, and Lactobacillus salivarius. The growth inhibition was dependent on the concentrations of the extracts. In contrast, the extracts did not inhibit the growth of the major indigenous intestinal lactic acid bacteria isolated from humans. These lactic acid bacteria ...

  11. Human Cortical Neural Stem Cells Expressing Insulin-Like Growth Factor-I: A Novel Cellular Therapy for Alzheimer's Disease.

    Science.gov (United States)

    McGinley, Lisa M; Sims, Erika; Lunn, J Simon; Kashlan, Osama N; Chen, Kevin S; Bruno, Elizabeth S; Pacut, Crystal M; Hazel, Tom; Johe, Karl; Sakowski, Stacey A; Feldman, Eva L

    2016-03-01

    Alzheimer's disease (AD) is the most prevalent age-related neurodegenerative disorder and a leading cause of dementia. Current treatment fails to modify underlying disease pathologies and very little progress has been made to develop effective drug treatments. Cellular therapies impact disease by multiple mechanisms, providing increased efficacy compared with traditional single-target approaches. In amyotrophic lateral sclerosis, we have shown that transplanted spinal neural stem cells (NSCs) integrate into the spinal cord, form synapses with the host, improve inflammation, and reduce disease-associated pathologies. Our current goal is to develop a similar "best in class" cellular therapy for AD. Here, we characterize a novel human cortex-derived NSC line modified to express insulin-like growth factor-I (IGF-I), HK532-IGF-I. Because IGF-I promotes neurogenesis and synaptogenesis in vivo, this enhanced NSC line offers additional environmental enrichment, enhanced neuroprotection, and a multifaceted approach to treating complex AD pathologies. We show that autocrine IGF-I production does not impact the cell secretome or normal cellular functions, including proliferation, migration, or maintenance of progenitor status. However, HK532-IGF-I cells preferentially differentiate into gamma-aminobutyric acid-ergic neurons, a subtype dysregulated in AD; produce increased vascular endothelial growth factor levels; and display an increased neuroprotective capacity in vitro. We also demonstrate that HK532-IGF-I cells survive peri-hippocampal transplantation in a murine AD model and exhibit long-term persistence in targeted brain areas. In conclusion, we believe that harnessing the benefits of cellular and IGF-I therapies together will provide the optimal therapeutic benefit to patients, and our findings support further preclinical development of HK532-IGF-I cells into a disease-modifying intervention for AD. PMID:26744412

  12. Growth responses of Picea mongolica seedlings to defoliation rate

    Institute of Scientific and Technical Information of China (English)

    ZOU Chun-jing; HAN Shi-jie; QI Shu-yan; XU Wen-duo; LI Dao-tang

    2005-01-01

    Picea mongolica W. D. Xu. is an endemic species in China. The spruce forest is only found in semi-arid habitat in Inner Mongolia Autonomous Region of China. Based on the simulative defoliation experiment, it was proved that Picea mongolica seedlings had the compensatory and overcompensatory effects under the certain defoliation rate. The results of variance analysis on growth indexes showed that in PM Ⅰ (natural regeneration seedlings under Picea mongolica forest), the differences of H1 (height in June 23) and H2 (height in September 3) were extremely significant, and the difference of D(diameter at the breast height) were not significant. In PM Ⅱ (artificial regeneration seedlings under Betula platyphylla Suk. forest), the difference of H1 was significant, the difference of H2 was not significant, and the difference of D was extremely significant. The regression equations were established and the compensatory and overcompensatory points were obtained. In PM Ⅰ , the compensatory points of H1, H2, and D were 0.7628, 0.7436, 0.5725, and the overcompensatory points were 0.6056, 0.5802 and 0.2909 respectively. In PM Ⅱ, the compensatory points of H1, H2, and D are 0.5012, 0.3421, 0.2488, and the overcompensatory points are 0.4137, 0.2633 and 0.0747 respectively. These results suggested that the induction of compensatory growth mechanisms in spruce seedlings required a threshold level of defoliation, and the insects in Picea mongolica forest could be controlled in a certain degree.

  13. Clostridial necrotic enteritis in chicken associated with growth rate depression

    Directory of Open Access Journals (Sweden)

    Adin Priadi

    2008-03-01

    Full Text Available Clostridium perfringens (C. perfringens is a normal inhabitant of the intestinal tract of chickens as well as a potential pathogen causing necrotic enteritis. C. perfringens only causes necrotic enteritis when it transforms from non-toxin producing type to toxin producing type. The alpha toxin, (phospholipase C is believed to be a key to the occurrence of Clostridial necrotic enteritis (CNE. The best known predisposing factor is mucosal damage, caused by coccidiosis that damages the intestinal lining, making the gut susceptible to infections including C. perfringens. The purpose of this study was to observe the chicken performance in experimental CNE and field cases of CNE. Diagnosis of CNE were made by latex agglutination test, isolation and identification of the agent. Pathological and histopathological changes were also observed. Experimentally, NE could be reproduced when Eimeria sp and C. perfringens spores are inoculated in chicken. Signs of an NE are wet litter and diarrhea, and an increase in mortality is not often obvious. The depression of growth rate and feed efficiency of chicken become noticeable by week 5 because of damage to the intestine and the subsequent reduction in digestion and absorption of food. Subclinical form of CNE was also frequently found in the field, leading to significant decreases in performance. Chicken gut samples examinations revealed that subclinical form of CNE causes damage to the intestinal mucosa caused by C. perfringens leads to decreased digestion and absorption, increased feed conversion ratio and reduced weight gain. Dual infection with C. perfringens and Eimeria sp. was frequently found in field. The results of these studies provide evidence for C. perfringens as a causative bacteria for growth depression.

  14. Rhizobacterial Strain Bacillus megaterium BOFC15 Induces Cellular Polyamine Changes that Improve Plant Growth and Drought Resistance

    Science.gov (United States)

    Zhou, Cheng; Ma, Zhongyou; Zhu, Lin; Xiao, Xin; Xie, Yue; Zhu, Jian; Wang, Jianfei

    2016-01-01

    Plant-growth-promoting rhizobacteria can improve plant growth, development, and stress adaptation. However, the underlying mechanisms are still largely unclear. We investigated the effects of Bacillus megaterium BOFC15 on Arabidopsis plants. BOFC15 produced and secreted spermidine (Spd), a type of polyamine (PA) that plays an important role in plant growth. Moreover, BOFC15 induced changes in the cellular PAs of plants that promoted an increase of free Spd and spermine levels. However, these effects were remarkably abolished by the addition of dicyclohexylamine (DCHA), a Spd biosynthetic inhibitor. Additionally, the inoculation with BOFC15 remarkably increased plant biomass, improved root system architecture, and augmented photosynthetic capacity. Inoculated plants also displayed stronger ability to tolerate drought stress than non-inoculated (control) plants. Abscisic acid (ABA) content was notably higher in the inoculated plants than in the control plants under drought stress and polyethylene glycol (PEG)-induced stress conditions. However, the BOFC15-induced ABA synthesis was markedly inhibited by DCHA. Thus, microbial Spd participated in the modulation of the ABA levels. The Spd-producing BOFC15 improved plant drought tolerance, which was associated with altered cellular ABA levels and activated adaptive responses. PMID:27338359

  15. The Italian Patient (Why Italian Growth Rates Diverges)

    OpenAIRE

    Scognamiglio Pasini Carlo

    2010-01-01

    The performance of Italian economy has always been a fascinating puzzle for economists, both during the miraculous economic boom and in the current age of zero growth. This paper identifies the sluggish productivity dynamic as the main explanatory factor of Italian growth limits. It analyses the existing relationship between productivity and growth from three different points of view: the Keynesian approach, Neo-monetarism and Supply-Side Economics. The paper analyses the Italian growth disea...

  16. Variation in coral growth rates with depth at Discovery Bay, Jamaica

    Energy Technology Data Exchange (ETDEWEB)

    Huston, M.

    1985-01-01

    Growth rates, determined by X-radiographic measurement of skeletal extension, decreased with depth for four of six species of coral examined at Discovery Bay, Jamaica. Growth of Porites astreoides, Montastrea annularis, Colpophyllia natans, and Siderastrea siderea decreased significantly with depth over a 1- to 30-m depth range. In Montastrea cavernosa, the highest growth rate occurred in the middle of the sampled depth range. Agaricia agaricites had no measurable change in growth rate with depth. A compilation of available growth data for Atlantic and Pacific corals shows a strong pattern of highest growth rates a short distance below the surface and a decrease with depth.

  17. Growth rate of sheep fed high fat ration

    Directory of Open Access Journals (Sweden)

    Darwinsyah Lubis

    1998-10-01

    Full Text Available Incorporating high amount of fats into the ration for ruminants will affect the rumen microbes adversely and will reducefiber digestion potential. To correct such negative effects, the free fatty acids used for feed should be bond with Ca++, so it canpassing through the rumen savely (rumen by-pass fat. To test the Ca-fat utilization biologically, 20 growing male Garut shee pwere used and fed with 4 type of isocaloric-isoprotein concentrate feed which were allotted based on a randomized block desig nwith 5 replications. The concentrate (C-A was a positive control diet, while C-B was substituted with 10% free fatty acids (negative control, C-C was substituted with 10% Ca-fat, and C-D with 15% Ca-fat. The concentrate feed was fed at 500 g/d, while forage (King grass was 4 kg/d. Results of the experiment showed that the negative effect of free fatty acids can be corrected if it was given in the form of Ca-fat. Growth rate curve indicating a good growing pattern, with average daily gain was 100.18, 87.68, 112.86, and 115.00 g/d (P0.05. Carcass production was relatively good, where for C-A, C-B, C-C, and C-D were 14.84, 14.68, 16.34, and 15.72 kg (P<0.05 respectively, with final live weights of 34.00, 31.74, 34.58, and 34.30 kg (P<0.05. It can be concluded that Ca-fat (rumen by-pass fat can be used as an energy source component for growing sheep diet, and give the best result at 10% substitution rate in concentrate feed.

  18. Investigations of DNA damage induction and repair resulting from cellular exposure to high dose-rate pulsed proton beams

    Science.gov (United States)

    Renis, M.; Borghesi, M.; Favetta, M.; Malfa, G.; Manti, L.; Romano, F.; Schettino, G.; Tomasello, B.; Cirrone, G. A. P.

    2013-07-01

    Studies regarding the radiobiological effects of low dose radiation, microbeam irradiation services have been developed in the world and today laser acceleration of protons and heavy ions may be used in radiation therapy. The application of different facilities is essential for studying bystander effects and relating signalling phenomena in different cells or tissues. In particular the use of ion beams results advantageous in cancer radiotherapy compared to more commonly used X-rays, since the ability of ions in delivering lethal amount of doses into the target tumour avoiding or limiting damage to the contiguous healthy tissues. At the INFN-LNS in Catania, a multidisciplinary radiobiology group is strategically structured aimed to develop radiobiological research, finalised to therapeutic applications, compatible with the use of high dose laser-driven ion beams. The characteristic non-continuous dose rates with several orders of magnitude of laser-driven ion beams makes this facility very interesting in the cellular systems' response to ultra-high dose rates with non-conventional pulse time intervals cellular studies. Our group have projected to examine the effect of high dose laser-driven ion beams on two cellular types: foetal fibroblasts (normal control cells) and DU145 (prostate cancer cells), studying the modulation of some different bio-molecular parameters, in particular cell proliferation and viability, DNA damage, redox cellular status, morphological alterations of both the cytoskeleton components and some cell organelles and the possible presence of apoptotic or necrotic cell death. Our group performed preliminary experiments with high energy (60 MeV), dose rate of 10 Gy/min, doses of 1, 2, 3 Gy and LET 1 keV/μm on human foetal fibroblasts (control cells). We observed that cell viability was not influenced by the characteristics of the beam, the irradiation conditions or the analysis time. Conversely, DNA damage was present at time 0, immediately

  19. Long-run growth rate in a random multiplicative model

    Energy Technology Data Exchange (ETDEWEB)

    Pirjol, Dan [Institute for Physics and Nuclear Engineering, 077125 Bucharest (Romania)

    2014-08-01

    We consider the long-run growth rate of the average value of a random multiplicative process x{sub i+1} = a{sub i}x{sub i} where the multipliers a{sub i}=1+ρexp(σW{sub i}₋1/2 σ²t{sub i}) have Markovian dependence given by the exponential of a standard Brownian motion W{sub i}. The average value (x{sub n}) is given by the grand partition function of a one-dimensional lattice gas with two-body linear attractive interactions placed in a uniform field. We study the Lyapunov exponent λ=lim{sub n→∞}1/n log(x{sub n}), at fixed β=1/2 σ²t{sub n}n, and show that it is given by the equation of state of the lattice gas in thermodynamical equilibrium. The Lyapunov exponent has discontinuous partial derivatives along a curve in the (ρ, β) plane ending at a critical point (ρ{sub C}, β{sub C}) which is related to a phase transition in the equivalent lattice gas. Using the equivalence of the lattice gas with a bosonic system, we obtain the exact solution for the equation of state in the thermodynamical limit n → ∞.

  20. An Analytic Approach for Calculating Frame Erasue Rate in Cellular GSM Networks

    Directory of Open Access Journals (Sweden)

    Ahmed M. Alaa

    2013-11-01

    Full Text Available The Quality of Service (QoS of a GSM system is quantified in terms of Bit Error Rate (BER and Frame Erasure Rate (FER observed by the user. The problem of obtaining analytical expressions for BER and FER in a fading channel with multiple cochannel interferers (CCI is an extremely complex mathematical problem. The reason for this complexity is that the involvement of several GSM physical layer modules is required to obtain an expression for the probability of bit error. Besides, one needs to obtain the statistical properties of faded cochannel interferers in order to obtain the raw BER of GMSK modulation. Thus, error rate metrics are usually obtained by simulating the GSM physical layer rather than treating the problem analytically. A reliable interface between system and link level models can be obtained by evaluating the BER and FER in terms of the Signal-to-Interference Ratio (SIR analytically, instead of the pre-defined statistical mapping data usually used in literature. In this work, bounds on the uplink BER and FER are obtained for the GSM physical layer assuming a CCI limited system where both the desired and interference signals are subjected to Rayleigh fading. The analysis considers GMSK modulation, convolutional coding and Frequency Hopping.

  1. Relative rate and location of intra-host HIV evolution to evade cellular immunity are predictable.

    Science.gov (United States)

    Barton, John P; Goonetilleke, Nilu; Butler, Thomas C; Walker, Bruce D; McMichael, Andrew J; Chakraborty, Arup K

    2016-01-01

    Human immunodeficiency virus (HIV) evolves within infected persons to escape being destroyed by the host immune system, thereby preventing effective immune control of infection. Here, we combine methods from evolutionary dynamics and statistical physics to simulate in vivo HIV sequence evolution, predicting the relative rate of escape and the location of escape mutations in response to T-cell-mediated immune pressure in a cohort of 17 persons with acute HIV infection. Predicted and clinically observed times to escape immune responses agree well, and we show that the mutational pathways to escape depend on the viral sequence background due to epistatic interactions. The ability to predict escape pathways and the duration over which control is maintained by specific immune responses open the door to rational design of immunotherapeutic strategies that might enable long-term control of HIV infection. Our approach enables intra-host evolution of a human pathogen to be predicted in a probabilistic framework. PMID:27212475

  2. Export incentives, exchange rate policy and export growth in Turkey

    NARCIS (Netherlands)

    S.J.G. van Wijnbergen; I. Arslan

    1993-01-01

    The driving forces behind the Turkish export miracle, and in fact its very existence, have remained a matter of debate We show there was a boom. As to contributing factors, import growth in the Middle East in excess of import growth elsewhere made a negative contribution. On exports to non-oil count

  3. Effects of the Growth Rate on Microstructures and Room Temperature Mechanical Properties of Directionally Solidified Mg-5.2Zn Alloy

    Science.gov (United States)

    Liu, Shaojun; Yang, Guangyu; Xiao, Lei; Luo, Shifeng; Jie, Wanqi

    2016-06-01

    Effects of the growth rate on the microstructures and room temperature mechanical properties of Mg-5.2Zn alloy were investigated using Bridgman method at a constant temperature gradient 30 K/mm with different growth rates (v = 10 ~ 100 μm/s). The microstructure of directionally solidified Mg-5.2Zn alloy is composed of dendrite primary α(Mg) phase and interdendritic α(Mg) + Mg7Zn3 eutectic, which agrees well with the predicted microstructure using Scheil model. The morphology of the primary α(Mg) phase transforms from cellular, to cellular-dendritic, and then to dendritic with the increase of growth rate from 10 μm/s to 100 μm/s. According to the Kurz-Fisher model, the approximate criterion growth rate for cellular/dendrite transition is determined to be about 12.7 μm/s, which just lies in the experimental result interval. Using non-linear fitting analysis, λ 1 (the primary dendrite arm spacing) and λ 2 (secondary dendrite arm spacing) were found to be dependent on v (growth rate) in the form of λ 1 = 8.6964 × 10-6 v -0.23983, λ 2 = 1.7703 × 10-6 v -0.34161, which is in good agreement with the calculated values by the Trivedi model and Kattamis-Flemings model, respectively. Furthermore, tensile test shows that the directional solidified experimental Mg-5.2Zn alloy shows higher strength than the non-directional solidified alloy under the same cooling rate. The dendritic structure shows higher strength than the cellular structure due to the fact that brittle interdendrite eutectic was refined in dendritic structures.

  4. Advanced Computational Approaches for Characterizing Stochastic Cellular Responses to Low Dose, Low Dose Rate Exposures

    Energy Technology Data Exchange (ETDEWEB)

    Scott, Bobby, R., Ph.D.

    2003-06-27

    applications of NEOTRANS2, indicate that nonlinear threshold-type, dose-response relationships for excess stochastic effects (problematic nonlethal mutations, neoplastic transformation) should be expected after exposure to low linear energy transfer (LET) gamma rays or gamma rays in combination with high-LET alpha radiation. Similar thresholds are expected for low-dose-rate low-LET beta irradiation. We attribute the thresholds to low-dose, low-LET radiation induced protection against spontaneous mutations and neoplastic transformations. The protection is presumed mainly to involve selective elimination of problematic cells via apoptosis. Low-dose, low-LET radiation is presumed to trigger wide-area cell signaling, which in turn leads to problematic bystander cells (e.g., mutants, neoplastically transformed cells) selectively undergoing apoptosis. Thus, this protective bystander effect leads to selective elimination of problematic cells (a tissue cleansing process in vivo). However, this protective bystander effects is a different process from low-dose stimulation of the immune system. Low-dose, low-LET radiation stimulation of the immune system may explain why thresholds for inducing excess cancer appear much larger (possibly more than 100-fold larger) than thresholds for inducing excess mutations and neoplastic transformations, when the dose rate is low. For ionizing radiation, the current risk assessment paradigm is such that the relative risk (RR) is always ¡Ý 1, no matter how small the dose. Our research results indicate that for low-dose or low-dose-rate, low-LET irradiation, RR < 1 may be more the rule than the exception. Directly tied to the current RR paradigm are the billion-dollar cleanup costs for radionuclide-contaminated DOE sites. Our research results suggest that continued use of the current RR paradigm for which RR ¡Ý 1 could cause more harm than benefit to society (e.g., by spreading unwarranted fear about phantom excess risks associated with low-dose low

  5. Nuclear epidermal growth factor receptor modulates cellular radio-sensitivity by regulation of chromatin access

    International Nuclear Information System (INIS)

    Purpose: Nuclear EGFR is involved in cellular stress management and regulation of cellular radio-sensitivity. The aim of this study was to elucidate the molecular mode of nuclear EGFR action. Methods: Radiation induced nuclear EGFR-shuttling and EGFR-foci formation was analyzed with immunohistochemistry and confocal microscopy. Composition of γH2AX-protein complexes was analyzed by western-blotting after immuno-precipitation. Functional relevance of nuclear EGFR was analyzed after siRNA mediated depletion of EGFR with respect to activation of ATM, histone H3 acetylation, residual DNA-damage and cell survival after irradiation. Results: Following radiation nuclear EGFR was localized in foci similar to γH2AX. EGFR co-localized in a sub-fraction of γH2AX-foci. Analysis of composition of γH2AX-complexes revealed presence of EGFR, ATM, promyelocytic leukemia protein (PML), histone H3 and hetero-chromatin binding protein (HP1) in response to radiation. Depletion of EGFR protein inhibited ATM activation due to inhibition of acetylase TIP60 activity following irradiation. Consequently, histone H3 acetylation and phosphorylation was blocked and chromatin could not be opened for repair. Thus, residual DNA-damage was increased 24 h after irradiation and cells were radio-sensitized. Comparable results were obtained when cells were treated with EGFR-NLS-peptide, which blocks EGFR nuclear shuttling specifically. Conclusions: Nuclear EGFR is part of DNA-damage repair complex and is involved in regulation of TIP60-acetylase activity. TIP60 is essential for ATM activation and chromatin relaxation which is a prerequisite for DNA-repair in heterochromatic DNA. Thus interventional EGFR strategies during tumor treatment may also interact with DNA-repair by blocking access to damaged DNA.

  6. Computer simulation of tumour growth and cellular phase distribution prior to radiotherapy

    International Nuclear Information System (INIS)

    Full text: A study into the optimal fractionation and schedule in combined chemo-radiotherapy for head and neck cancer has imposed the development of a computer model of tumour growth. The model is based on biological parameters, and characterises tumour growth and eventual tumour regression when chemo-radiotherapy is used. Tumour growth starting from a single stem cell is modelled using the Monte Carlo method. The type of the cell function, their relative proportions on mitosis, their proliferative capacity, the duration of the four phases of the cell cycle, the mean cell cycle time, and the cell loss due to natural causes are the main parameters of the basic model. A Gaussian distribution function operates in establishing the cell cycle time, with a mean value of 26 hours, while the cell type is sampled from a uniform distribution. With the established model, the sensitivity of the developed tumour's cell population to the stem, proliferative and non proliferative ratio at mitosis was assessed. The present model accurately reflects the exponential distribution of cells along the cell cycle (70% cells in G1 phase, 15% in S, 10% in G2, 5% in M) of a developed tumour as described in the literature. The proportion of stem, finitely proliferating and resting cells during tumour growth is maintained within their biological limits (2% stem. 23% finitely proliferating, 75% nonproliferating cells). The ratio (R=3) between the time necessary to develop a clinically detectable tumour (109 cells) and the time to grow to its lethal size (1012 cells) is in accordance with the biological data when tumour volume is compared for the two periods (30 doublings and 10 doublings respectively). Computer simulation can illustrate the biological growth of a tumour and the cell distribution along the cell cycle. These distributions may than be used in the assessment of tumour response to radiotherapy and to specific chemotherapeutic agents. Copyright (2001) Australasian College of

  7. Dispersion fraction enhances cellular growth of carbon nanotube and aluminum oxide reinforced ultrahigh molecular weight polyethylene biocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Patel, Anup Kumar; Balani, Kantesh, E-mail: kbalani@iitk.ac.in

    2015-01-01

    Ultrahigh molecular weight polyethylene (UHMWPE) is widely used as bone-replacement material for articulating surfaces due to its excellent wear resistance and low coefficient of friction. But, the wear debris, generated during abrasion between mating surfaces, leads to aseptic loosening of implants. Thus, various reinforcing agents are generally utilized, which may alter the surface and biological properties of UHMWPE. In the current work, the cellular response of compression molded UHMWPE upon reinforcement of bioactive multiwalled carbon nanotubes (MWCNTs) and bioinert aluminum oxide (Al{sub 2}O{sub 3}) is investigated. The phase retention and stability were observed using X-ray diffraction, Raman spectroscopy and Fourier transform infrared (FTIR) spectroscopy. The reinforcement of MWCNTs and Al{sub 2}O{sub 3} has shown to alter the wettability (from contact angle of ∼ 88° ± 2° to ∼ 118° ± 4°) and surface energy (from ∼ 23.20 to ∼ 17.75 mN/m) of composites with respect to UHMWPE, without eliciting any adverse effect on cytocompatibility for the L929 mouse fibroblast cell line. Interestingly, the cellular growth of the L929 mouse fibroblast cell line is observed to be dominated by the dispersion fraction of surface free energy (SFE). After 48 h of incubation period, a decrease in metabolic activity of MWCNT–Al{sub 2}O{sub 3} reinforced composites is attributed to apatite formation that reduces the dispersion fraction of surface energy. The mineralized apatite during incubation was confirmed and quantified by energy dispersive spectroscopy and X-ray diffraction respectively. Thus, the dispersion fraction of surface free energy can be engineered to play an important role in achieving enhanced metabolic activity of the MWCNT–Al{sub 2}O{sub 3} reinforced UHMWPE biopolymer composites. - Highlights: • The cellular response of UHMWPE upon MWCNT and Al{sub 2}O{sub 3} reinforcement is highlighted. • Wettability decreases with Al{sub 2}O{sub 3} and

  8. Dispersion fraction enhances cellular growth of carbon nanotube and aluminum oxide reinforced ultrahigh molecular weight polyethylene biocomposites

    International Nuclear Information System (INIS)

    Ultrahigh molecular weight polyethylene (UHMWPE) is widely used as bone-replacement material for articulating surfaces due to its excellent wear resistance and low coefficient of friction. But, the wear debris, generated during abrasion between mating surfaces, leads to aseptic loosening of implants. Thus, various reinforcing agents are generally utilized, which may alter the surface and biological properties of UHMWPE. In the current work, the cellular response of compression molded UHMWPE upon reinforcement of bioactive multiwalled carbon nanotubes (MWCNTs) and bioinert aluminum oxide (Al2O3) is investigated. The phase retention and stability were observed using X-ray diffraction, Raman spectroscopy and Fourier transform infrared (FTIR) spectroscopy. The reinforcement of MWCNTs and Al2O3 has shown to alter the wettability (from contact angle of ∼ 88° ± 2° to ∼ 118° ± 4°) and surface energy (from ∼ 23.20 to ∼ 17.75 mN/m) of composites with respect to UHMWPE, without eliciting any adverse effect on cytocompatibility for the L929 mouse fibroblast cell line. Interestingly, the cellular growth of the L929 mouse fibroblast cell line is observed to be dominated by the dispersion fraction of surface free energy (SFE). After 48 h of incubation period, a decrease in metabolic activity of MWCNT–Al2O3 reinforced composites is attributed to apatite formation that reduces the dispersion fraction of surface energy. The mineralized apatite during incubation was confirmed and quantified by energy dispersive spectroscopy and X-ray diffraction respectively. Thus, the dispersion fraction of surface free energy can be engineered to play an important role in achieving enhanced metabolic activity of the MWCNT–Al2O3 reinforced UHMWPE biopolymer composites. - Highlights: • The cellular response of UHMWPE upon MWCNT and Al2O3 reinforcement is highlighted. • Wettability decreases with Al2O3 and MWCNT reinforcement without any adverse effect on cytocompatibility.

  9. Ice Crystal Growth Rates Under Upper Troposphere Conditions

    Science.gov (United States)

    Peterson, Harold S.; Bailey, Matthew; Hallett, John

    2010-01-01

    Atmospheric conditions for growth of ice crystals (temperature and ice supersaturation) are often not well constrained and it is necessary to simulate such conditions in the laboratory to investigate such growth under well controlled conditions over many hours. The growth of ice crystals from the vapour in both prism and basal planes was observed at temperatures of -60 C and -70 C under ice supersaturation up to 100% (200% relative humidity) at pressures derived from the standard atmosphere in a static diffusion chamber. Crystals grew outward from a vertical glass filament, thickening in the basal plane by addition of macroscopic layers greater than 2 m, leading to growth in the prism plane by passing of successive layers conveniently viewed by time lapse video.

  10. Stress corrosion crack growth rates and general corrosion rates at crack tips of steels in high temperature water

    International Nuclear Information System (INIS)

    The maximum stress corrosion crack growth rates for a number of structural materials (steels and nickel alloys) have been measured in 288 C water. Also, the general corrosion rates of these materials have been determined from weight loss experiments in simulated stress corrosion crack tip electrolytes at 288 C. It is shown that the stress corrosion crack growth rates are typically twenty times faster than the general corrosion rates. This correlation holds over five orders of magnitude. It is concluded that strategies to prevent stress corrosion cracking in high temperature aqueous environments might include alloys of higher general corrosion resistance

  11. Single-walled carbon nanotubes: a nano-specific enhancer of cellular growth in LB culture

    International Nuclear Information System (INIS)

    We conducted a study to characterize the antimicrobial properties of SWNTs to B.subtilis in a saline solution or in a LB culture. Dimensions and the antibacterial ability of SWNTs in a saline solution were different from those in a LB culture. Transmission and scanning electron microscopes were used to characterize the SWNTs structure with and without LB culture. The antibacterial ability of SWNTs was affected by the environment of bacterial growth. The antibacterial mechanism of SWNTs was studied,too. (authors)

  12. Multiscale characterization of cardiac remodeling induced by intrauterine growth restriction, at organ, cellular and subcellular level

    OpenAIRE

    González Tendero, Anna

    2014-01-01

    Tesi realitzada a l'Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS) INTRODUCTION: Intrauterine growth restriction (IUGR) due to placental insufficiency affects up to 7-10% of pregnancies and is a major cause of perinatal mortality and long term morbidity. IUGR results in low birth weight, which is associated with increased risk of cardiovascular mortality in adulthood, and is thought to be mediated by fetal cardiovascular programming. IUGR fetuses show signs of cardiac s...

  13. The Real Exchange Rate and Growth in Zimbabwe: Does the Currency Regime Matter?

    OpenAIRE

    Brixiova, Zuzana; Ncube, Mthuli

    2014-01-01

    Zimbabwe faces growth and external competitiveness challenges, as indicated by its low trend growth and investment, declining share in the world exports, high current account deficits, and external debt. The stock-flow approach to the equilibrium exchange rate reveals that the real exchange rate experienced periods of sizeable overvaluation, both prior to the 2008 economic collapse and under the current multicurrency regime. While overvaluation hampers GDP growth, as well as growth and employ...

  14. Working Paper - 210 - The Real Exchange Rate and Growth in Zimbabwe Does the Currency Regime Matter

    OpenAIRE

    Zuzana Brixiova; Mthuli Ncube

    2014-01-01

    Zimbabwe faces growth and external competitiveness challenges, as indicated by its low trend growth and investment, declining share in the world exports, high current account deficits, and external debt. The stock-flow approach to the equilibrium exchange rate reveals that the real exchange rate experienced periods of sizeable overvaluation, both prior to the 2008 economic collapse and under the current multicurrency regime. While overvaluation hampers GDP growth, as well as growth and employ...

  15. Impact of Food Beverage Price Index and Exchange Rate Volatility on Economic Growth

    OpenAIRE

    Onasanya Olanrewaju k; Adeniji Oyebimpe Emmanuel

    2014-01-01

    Many factors such as money supply, exchange rate, interest rate, gross domestic product, inflation rate, unemployment rate, frictional unemployment and other flow variables have great impact on economic growth rate. These factors have significant effect on capital movement, business outlook and economic development. Over past decades, numerous studies have used these variables to investigate their impact on economic growth especially using the econometric approach. Results obtained from such ...

  16. Activation of arylhydrocarbon receptor (AhR) in T lineage cells inhibits cellular growth

    Energy Technology Data Exchange (ETDEWEB)

    Nohara, K.; Tomohiro, I.; Chiharu, T. [National Institute for Environmental Studies, Tsukuba (Japan)

    2004-09-15

    Dioxins, including the most toxic congener, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), exert their toxic effects by binding and activating the arylhydrocarbon receptor (AhR), a liganddependent transcription factor. Upon binding dioxins, the AhR in the cytoplasm is activated and translocated to the nucleus, where it heterodimerizes with another transcription factor, ARNT. The AhR/ARNT heterodimer modulates expressions of various genes by binding xenobiotic responsive elements (XREs) in their enhancer regions or modifies cellular functions through protein-protein interactions. The AhR activation by TCDD exposure induces various immunotoxic reactions including thymus involution and suppression of T cell-dependent antibody production. We have investigated the roles of AhR activation in T lineage cells and their underlying mechanisms by generating transgenic (Tg) mice expressing a constitutively active AhR (CA-AhR) mutant specifically in T cells and by transiently expressing the CA-AhR mutant in Jurkat T cells.

  17. Growth rate change driven by external perturbation in the azuki bean weevil

    CERN Document Server

    Fukano, T

    2003-01-01

    In laboratory experiments we obtain that the apparent growth rate of the population becomes larger than one under the normal condition, triggered by the external perturbation as the removal of individuals. The changed growth rate is stable for a while. We also propose a simple model of population dynamics allowing both matching and mis-matching the trend of the external perturbation, and show that the growth rate of the model population is changeable and stable to some extent.

  18. Individual Growth Rates of Nikolsky’s Viper, Vipera berus nikolskii (Squamata, Viperidae

    Directory of Open Access Journals (Sweden)

    Bondarenko Z. S.

    2016-02-01

    Full Text Available Capture-mark-recapture data was used to infer growth rates of the Nikolsky’s viper, Vipera berus nikolskii (Vedmederja, Grubant et Rudaeva, 1986, in the Eastern Ukraine. We have found that growth rate is negatively correlated with age. The difference in growth rates before maturation is not significant between different sexes. Growth rates decrease rapidly after maturation in males and females, however adult males retain significantly higher average growth rates. There is large dispersion of growth rates in the group of adult females, which is caused, probably, by alteration of complete arrest of growth in the years with reproduction and more intensive growth in the years without it. Asymptotic snout-ventral length estimated after Von Bertalanffy model was 680 mm in females and 630 mm in males. Females mature after fifth and males mature after fourth hibernation. The larger females in vipers can not be the result of higher growth rates in females, but are the outcome of a combination of other factors including different maturation time and size (older and being larger, and, perhaps, longer life span due to lower mortality. Growth rates of the Nikolsky’s viper in the nature are higher than in other species in the group of small Eurasian vipers.

  19. Effect of cold work on initiation stage crack growth rate of nickel based alloys

    International Nuclear Information System (INIS)

    To investigate the effect of cold work on initiation stage crack growth rates of nickel based alloy, initiation stage crack growth rates were measured for simulated PWR primary water conditions using flat type specimens which were prepared from three different heats of alloy 600 and then 20 and 40% cold worked. Almost all data showed the stress had an increasing linear dependency on crack growth rate ; however there was some scattering of data and some materials showed a different tendency. Since yield strength was increased by cold work, for the same stress, the initiation stage crack growth rates were restrained or were not changed significantly by cold work. (author)

  20. Targeted Nanogel Conjugate for Improved Stability and Cellular Permeability of Curcumin: Synthesis, Pharmacokinetics, and Tumor Growth Inhibition

    Science.gov (United States)

    2015-01-01

    Curcumin (CUR) is a unique natural compound with promising anticancer and anti-inflammatory activities. However, the therapeutic efficacy of curcumin was challenged in clinical trials, mostly due to its low bioavailability, rapid metabolism, and elimination. We designed a nanodrug form of curcumin, which makes it stable and substantially enhances cellular permeability and anticancer activity at standard oral administration. Curcumin was conjugated as an ester to cholesteryl-hyaluronic acid (CHA) nanogel that is capable of targeted delivery to CD44-expressing drug-resistant cancer cells. CHA-CUR nanogels demonstrated excellent solubility and sustained drug release in physiological conditions. It induced apoptosis in cancer cells, suppressing the expression of NF-κB, TNF-α, and COX-2 cellular targets similar to free curcumin. Pharmacokinetic/pharmacodynamic (PK/PD) studies also revealed improved circulation parameters of CHA-CUR at oral, i.p. and i.v. administration routes. CHA-CUR showed targeted tumor accumulation and effective tumor growth inhibition in human pancreatic adenocarcinoma MiaPaCa-2 and aggressive orthotropic murine mammary carcinoma 4T1 animal models. CHA-CUR treatment was well-tolerated and resulted in up to 13-fold tumor suppression, making this nanodrug a potential candidate for cancer prevention and therapeutic treatment. PMID:25072100

  1. Climate forcing growth rates: doubling down on our Faustian bargain

    Science.gov (United States)

    Hansen, James; Kharecha, Pushker; Sato, Makiko

    2013-03-01

    Rahmstorf et al 's (2012) conclusion that observed climate change is comparable to projections, and in some cases exceeds projections, allows further inferences if we can quantify changing climate forcings and compare those with projections. The largest climate forcing is caused by well-mixed long-lived greenhouse gases. Here we illustrate trends of these gases and their climate forcings, and we discuss implications. We focus on quantities that are accurately measured, and we include comparison with fixed scenarios, which helps reduce common misimpressions about how climate forcings are changing. Annual fossil fuel CO2 emissions have shot up in the past decade at about 3% yr-1, double the rate of the prior three decades (figure 1). The growth rate falls above the range of the IPCC (2001) 'Marker' scenarios, although emissions are still within the entire range considered by the IPCC SRES (2000). The surge in emissions is due to increased coal use (blue curve in figure 1), which now accounts for more than 40% of fossil fuel CO2 emissions. Figure 1. Figure 1. CO2 annual emissions from fossil fuel use and cement manufacture, an update of figure 16 of Hansen (2003) using data of British Petroleum (BP 2012) concatenated with data of Boden et al (2012). The resulting annual increase of atmospheric CO2 (12-month running mean) has grown from less than 1 ppm yr-1 in the early 1960s to an average ~2 ppm yr-1 in the past decade (figure 2). Although CO2 measurements were not made at sufficient locations prior to the early 1980s to calculate the global mean change, the close match of global and Mauna Loa data for later years suggests that Mauna Loa data provide a good approximation of global change (figure 2), thus allowing a useful estimate of annual global change beginning with the initiation of Mauna Loa measurements in 1958 by Keeling et al (1973). Figure 2. Figure 2. Annual increase of CO2 based on data from the NOAA Earth System Research Laboratory (ESRL 2012). CO2 change

  2. Effect of growth rate and pH on intracellular levels and activities of the components of the phosphoenolpyruvate: sugar phosphotransferase system in Streptococcus mutans Ingbritt.

    OpenAIRE

    Vadeboncoeur, C; St Martin, S; Brochu, D.; Hamilton, I R

    1991-01-01

    The growth of Streptococcus mutants Ingbritt in continuous culture at low pH or high growth rates repressed the biosynthesis of the components of the phosphoenolpyruvate:sugar phosphotransferase system (PTS). The cellular concentrations of the soluble components HPr, enzyme I (EI), and EIII for mannose (IIIman) and EII activity for glucose, mannose, 2-deoxyglucose (2DG), and fructose were determined in membrane preparations from cells grown at pHs from 8.0 to 5.0 and at dilution (D) or growth...

  3. The physiological basis of reaction norms: the interaction among growth rate, the duration of growth and body size.

    Science.gov (United States)

    Davidowitz, Goggy; Nijhout, H Frederik

    2004-12-01

    The general effects of temperature and nutritional quality on growth rate and body size are well known. We know little, however, about the physiological mechanisms by which an organism translates variation in diet and temperature into reaction norms of body size or development time. We outline an endocrine-based physiological mechanism that helps explain how this translation occurs in the holometabolous insect Manduca sexta (Sphingidae). Body size and development time are controlled by three factors: (i) growth rate, (ii) the timing of the cessation of juvenile hormone secretion (measured by the critical weight) and (iii) the timing of ecdysteroid secretion leading to pupation (the interval to cessation of growth [ICG] after reaching the critical weight). Thermal reaction norms of body size and development time are a function of how these three factors interact with temperature. Body size is smaller at higher temperatures, because the higher growth rate decreases the ICG, thereby reducing the amount of mass that can accumulate. Development time is shorter at higher temperatures because the higher growth rate decreases the time required to attain the critical weight and, independently, controls the duration of the ICG. Life history evolution along altitudinal, latitudinal and seasonal gradients may occur through differential selection on growth rate and the duration of the two independently controlled determinants of the growth period. PMID:21676730

  4. The Effect of Load-Line Displacement Rate on the SCC Growth Rate of Nickel Alloys and Mechanistic Implications

    Energy Technology Data Exchange (ETDEWEB)

    D Morton

    2005-10-19

    A key set of SCC growth experiments was designed to test the hypothesis that deformation/creep is the rate controlling step in LPSCC. These tests were performed on Alloy X-750 AH compact tension specimens at a various constant displacement rates. The deformation/creep rate within the crack tip zone is proportional to the test displacement rate. If crack growth rates were observed to increase with the load-line displacement rate, then this would indicate that deformation/creep is a critical SCC mechanism process. However, results obtained from the load-line displacement tests did not find X-750 AH SCC growth rate to be dependent on the position rate and therefore do not support the assumption that deformation/creep is the rate controlling process in LPSCC. The similarities between the SCC response of X-750, Alloy 600 and EN82H suggests that it is likely that the same SCC process is occurring for all these alloys (i.e., the same rate controlling step) and that deformation based models are also inappropriate for Alloy 600 and EN82H. The strong temperature and coolant hydrogen dependencies exhibited by these alloys make it more likely that nickel alloy LPSCC is controlled by an environmental or corrosion driven process.

  5. Strictly Endogenous Growth with Non-renewable Resources Implies an Unbounded Growth Rate

    OpenAIRE

    Groth, Christian

    2003-01-01

    Conventional endogenous growth theory relies on the assumption of constant returns to ”broad capital”. As Solow pointed out, the strength of this assumption is revealed by recognizing that even the slightest touch of increasing returns creates explosive growth: infinite output in finite time! But Solow’s observation ignored natural resources. What happens if non-renewable resources enter the ”growth engine”? In this case (strictly) endogenous growth requires the technology to be such that the...

  6. Non-Linearity between Inflation Rate and GDP Growth in Malaysia

    OpenAIRE

    Qaiser Munir; Kasim Mansur

    2009-01-01

    This study analyses the relationship between inflation rate and economic growth rate in the period 1970-2005 in Malaysia. A specific question that is addressed in this study is what the threshold inflation rate for Malaysia. The findings suggest that there is one inflation threshold value exist for Malaysia. This evidence strongly supports the view that the relationship between inflation rate and economic growth is nonlinear. The estimated threshold regression model suggests 3.89% as the thre...

  7. Energy and Growth under Flexible Exchange Rates: A Simulation Study

    OpenAIRE

    Sachs, Jeffrey D

    1980-01-01

    This paper offers a theoretical framework for studying the inter-actions of energy prices and economic growth. The incorporation of energy prices and quantities in a macroeconomic setting focuses on (1)the aggregate technology; (2) the interdependence of energy producers and consumers in the world economy; and (3) the asset markets as the channel through which energy price changes affect output and capital accumulation. While several existing studies consider aspects of these issues, none pro...

  8. Modification of the cellular heat sensitivity of cucumber by growth under supplemental ultraviolet-B radiation

    International Nuclear Information System (INIS)

    The effect of ultraviolet B (UV-B) radiation on the thermal sensitivity of cucumber (Cucumis sativus L.) was studied using UV-B-sensitive cv Poinsett 76 and UV-B-resistant cv Ashley grown under control and elevated (300 mW m-2) UV-B radiation levels. Using both cotyledon and leaf discs, the ability of the tissue to reduce triphenyl tetrazolium chloride (TTC) was determined after treatment at 50 degrees C for various times. Semilogarithmic plots of TTC reduction as a function of time at 50 degrees were curvilinear. They were monophasic for the control cucumber and biphasic for cucumber grown in the presence of elevated UV-B. Treatment of cucumber plants at 37 degrees C for 24 h or of tissue discs at acute UV-B levels for 1 h further modified their response to elevated temperature. These results suggest that growth of cucumber under enhanced UV-B radiation levels increased its ability to withstand elevated temperatures. 19 refs., 2 figs., 2 tabs

  9. The impact of risk management on internal and sustainable growth rate: Evidence from Tehran Stock Exchange

    Directory of Open Access Journals (Sweden)

    Hamid Reza Vakili Fard

    2014-09-01

    Full Text Available Measuring the relative risk of firms has been an open discussion among researchers. There are many studies on learning how leverage may influence on growth of the firms. This article reviews the relationship between risk management, internal and sustainable growth of accepted companies in Tehran stock exchange. The survey considers three types of risks including operating, financial and compound and investigates their relationships with internal growth rate as well as sustainable growth rate. Using some regression techniques, the study has determined negative and meaningful relationships between different types of leverage on side and internal as well as sustainable growth on the other side.

  10. Different Transcriptional Responses from Slow and Fast Growth Rate Strains of Listeria monocytogenes Adapted to Low Temperature

    Science.gov (United States)

    Cordero, Ninoska; Maza, Felipe; Navea-Perez, Helen; Aravena, Andrés; Marquez-Fontt, Bárbara; Navarrete, Paola; Figueroa, Guillermo; González, Mauricio; Latorre, Mauricio; Reyes-Jara, Angélica

    2016-01-01

    Listeria monocytogenes has become one of the principal foodborne pathogens worldwide. The capacity of this bacterium to grow at low temperatures has opened an interesting field of study in terms of the identification and classification of new strains of L. monocytogenes with different growth capacities at low temperatures. We determined the growth rate at 8°C of 110 strains of L. monocytogenes isolated from different food matrices. We identified a group of slow and fast strains according to their growth rate at 8°C and performed a global transcriptomic assay in strains previously adapted to low temperature. We then identified shared and specific transcriptional mechanisms, metabolic and cellular processes of both groups; bacterial motility was the principal process capable of differentiating the adaptation capacity of L. monocytogenes strains with different ranges of tolerance to low temperatures. Strains belonging to the fast group were less motile, which may allow these strains to achieve a greater rate of proliferation at low temperature. PMID:26973610

  11. Economic growth and currency crisis: A real exchange rate entropic approach

    OpenAIRE

    Matesanz Gómez, David; Guillermo J. Ortega

    2005-01-01

    We propose a country classification of economic growth currency crisis consequences based on the entropic analysis of the real exchange rate. We show that this ranking is highly correlated with the annual minimum rate of growth, a proxy used to quantify real currency crisis effects.

  12. Geographic After-Tax Real Income Differentials and Population Growth Rates

    OpenAIRE

    Alexander, Gigi; Cebula, Richard; Koch, James

    1989-01-01

    This empirical note investigates the impact of geographic after-tax real, as opposed to nominal, income differentials on geographic population growth rates. The focus is on Florida's 67 counties and the 1980-88 time period. The empirical results imply that the population growth rate in Florida counties was of after-tax real income.

  13. THE GROWTH RATE AND STATISTICAL FLUCTUATION OF BOSE-EINSTEIN CONDENSATE FORMATION

    Institute of Scientific and Technical Information of China (English)

    Yan Ke-zhu; Tan Wei-han

    2000-01-01

    Using the generating function method to solve the master equation ofBose-Einstein condensate and to evaluate the growth rate, statisticalfluctuation of condensate atoms, we find out that there is a plateau inthe growth rate curve and a super-Poisson distribution observed.

  14. A re-examination of tigerfish growth rates in Lake Kariba

    OpenAIRE

    Beattie, I.H.

    1982-01-01

    Growth rates of male and female tigerfish Hydrocynus vittatus were determined from length/frequencies of fish from the Sanyati Basin and Sinamwenda estuary, Lake Kariba. Growth rates were similar in both sexes for the first two years, after which females grew faster and reached a greater length. Fish from the Sanyati Basin appeared to grow slightly faster than those from the Sinamwenda Estuary.

  15. Family poverty affects the rate of human infant brain growth.

    Directory of Open Access Journals (Sweden)

    Jamie L Hanson

    Full Text Available Living in poverty places children at very high risk for problems across a variety of domains, including schooling, behavioral regulation, and health. Aspects of cognitive functioning, such as information processing, may underlie these kinds of problems. How might poverty affect the brain functions underlying these cognitive processes? Here, we address this question by observing and analyzing repeated measures of brain development of young children between five months and four years of age from economically diverse backgrounds (n = 77. In doing so, we have the opportunity to observe changes in brain growth as children begin to experience the effects of poverty. These children underwent MRI scanning, with subjects completing between 1 and 7 scans longitudinally. Two hundred and three MRI scans were divided into different tissue types using a novel image processing algorithm specifically designed to analyze brain data from young infants. Total gray, white, and cerebral (summation of total gray and white matter volumes were examined along with volumes of the frontal, parietal, temporal, and occipital lobes. Infants from low-income families had lower volumes of gray matter, tissue critical for processing of information and execution of actions. These differences were found for both the frontal and parietal lobes. No differences were detected in white matter, temporal lobe volumes, or occipital lobe volumes. In addition, differences in brain growth were found to vary with socioeconomic status (SES, with children from lower-income households having slower trajectories of growth during infancy and early childhood. Volumetric differences were associated with the emergence of disruptive behavioral problems.

  16. EXCHANGE RATE AND ECONOMIC GROWTH. THE CASE OF ROMANIA

    Directory of Open Access Journals (Sweden)

    Nicolae Ghiba

    2010-12-01

    Full Text Available Considering the difficulties created by the economic crisis, many exporters have criticized the National Bank of Romania (NBR’s policy regarding the exchange rate evolution. They argue that depreciation is a necessary condition for recovery and not financial stability. On the contrary, Romania cannot afford a shock in the exchange rate level. The risk associated with such a measure is too high for an emerging country and it annihilates any export competitive advantages. Therefore, depreciation may delay the imperative of Romanian economic recovery. A solid economic recovery should have as starting point a financial system sound and stable. Excessive exchange rate depreciation jeopardizes the financial soundness of banks and the borrower’s ability to repay their loans. Therefore, it creates inflationary flare-ups, particularly dangerous for the economy of any state.

  17. Effects of cellular iron deficiency on the formation of vascular endothelial growth factor and angiogenesis. Iron deficiency and angiogenesis

    OpenAIRE

    Eckard Jonathan; Dai Jisen; Wu Jing; Jian Jinlong; Yang Qing; Chen Haobin; Costa Max; Frenkel Krystyna; Huang Xi

    2010-01-01

    Abstract Background Young women diagnosed with breast cancer are known to have a higher mortality rate from the disease than older patients. Specific risk factors leading to this poorer outcome have not been identified. In the present study, we hypothesized that iron deficiency, a common ailment in young women, contributes to the poor outcome by promoting the hypoxia inducible factor-1α (HIF-1α and vascular endothelial growth factor (VEGF) formation. This hypothesis was tested in an in vitro ...

  18. Effects of begging on growth rates of nestling chicks

    OpenAIRE

    Rodríguez-Gironés, Miguel Ángel; Jesús M Zúñiga; Redondo, T.

    2001-01-01

    We investigated whether an increase in begging levels delays growth of chicks. In experiment 1, we hand-reared nine pairs of ring dove squabs, divided into a control and a begging group. All squabs received similar amounts of food, but those in the begging group had to beg for a prolonged period in order to be fed, while squabs in the control group received food without begging. Squabs stopped responding to the treatment after 10 days and, at that time, there was no effect of induced begging ...

  19. Specimen size-considerations in fatigue crack growth rate testing

    International Nuclear Information System (INIS)

    The effect of specimen size upon the fatigue-crack growth behavior of annealed AISI Type 304 stainless steel was studied at two stress ratios at an elevated temperature. The resulting data were examined in the light of the present ASTM size criterion (based upon monotonic yield stength) as well as a proposed criterion based upon the material flow strength. The flow stress criterion is considerably less restrictive than the present ASTM Criterion, and the results of this study indicate that the flow stress criterion is entirely appropriate for strain-hardening materials such as the austenitic stainless steels

  20. Rate of growth of Pseudomonas fluorescens in donated blood.

    OpenAIRE

    Gibb, A. P.; Martin, K M; Davidson, G A; Walker, B.; Murphy, W G

    1995-01-01

    AIMS--To examine how delayed refrigeration of blood affects the growth of Pseudomonas fluorescens, one of the two most important causes of sepsis resulting from transfusion of contaminated blood. METHODS--Two donations of whole blood were each divided into three aliquots and inoculated with 5-10 cfu/ml of a P fluorescens strain from a case of transfusion associated sepsis. From each donation, one aliquot was placed at 4 degrees C, one was held at 20 degrees C for six hours prior to refrigerat...

  1. Nucleation kinetics and crystal growth with fluctuating rates at the intermediate stage of phase transitions

    International Nuclear Information System (INIS)

    Crystal growth kinetics accompanied by particle growth with fluctuating rates at the intermediate stage of phase transitions is analyzed theoretically. The integro-differential model of governing equations is solved analytically for size-independent growth rates and arbitrary dependences of the nucleation frequency on supercooling/supersaturation. Two important cases of Weber–Volmer–Frenkel–Zel'dovich and Mier nucleation kinetics are detailed. A Fokker–Plank type equation for the crystal-size density distribution function is solved explicitly. (paper)

  2. PWSCC crack growth rate of alloy 690 to simulate actual plant material

    International Nuclear Information System (INIS)

    In order to understand the PWSCC crack growth rate of domestically produced alloy 690, alloy 690 materials were obtained from two companies which supply materials that are used in actual plants. PWSCC crack growth rates of cold worked alloy TT690 were measured under simulated PWR primary water conditions. The crack growth rates of 20% cold-worked alloy TT690 from both companies were less than 5×10-11 m/s, and the crack growth rates were not as fast as reported from Bettis. Also it was observed that there was up to about 2.5 times difference in the crack growth rates of TT690 of the two companies. (author)

  3. How Do Output Growth Rate Distributions Look Like? Some Time-Series Evidence on OECD Countries

    CERN Document Server

    Fagiolo, G; Roventini, A; Fagiolo, Giorgio; Napoletano, Mauro; Roventini, Andrea

    2006-01-01

    This paper investigates the statistical properties of within-country GDP and industrial production (IP) growth rate distributions. Many empirical contributions have recently pointed out that cross-section growth rates of firms, industries and countries all follow Laplace distributions. In this work, we test whether also within-country, time-series GDP and IP growth rates can be approximated by tent-shaped distributions. We fit output growth rates with the exponential-power (Subbotin) family of densities, which includes as particular cases both the Gaussian and the Laplace distributions. We find that, for a large number of OECD countries including the U.S., both GDP and IP growth rates are Laplace distributed. Moreover, we show that fat-tailed distributions robustly emerge even after controlling for outliers, autocorrelation and heteroscedasticity.

  4. Divalent metals stabilize cellular prion proteins and alter the rate of proteinase-K dependent limited proteolysis

    Science.gov (United States)

    Background: The key biochemical event in the pathogenesis of prion diseases is the conversion of normal cellular prion proteins (PrP**c) to the proteinase K (PK) resistant, abnormal form (PrP**sc); however, the cellular mechanisms underlying the conversion remain enigmatic. Binding of divalent ca...

  5. Effects of Eucommia ulmoides extract on longitudinal bone growth rate in adolescent female rats.

    Science.gov (United States)

    Kim, Ji Young; Lee, Jeong-Il; Song, MiKyung; Lee, Donghun; Song, Jungbin; Kim, Soo Young; Park, Juyeon; Choi, Ho-Young; Kim, Hocheol

    2015-01-01

    Eucommia ulmoides is one of the popular tonic herbs for the treatment of low back pain and bone fracture and is used in Korean medicine to reinforce muscles and bones. This study was performed to investigate the effects of E. ulmoides extract on longitudinal bone growth rate, growth plate height, and the expressions of bone morphogenetic protein 2 (BMP-2) and insulin-like growth factor 1 (IGF-1) in adolescent female rats. In two groups, we administered a twice-daily dosage of E. ulmoides extract (at 30 and 100 mg/kg, respectively) per os over 4 days, and in a control group, we administered vehicle only under the same conditions. Longitudinal bone growth rate in newly synthesized bone was observed using tetracycline labeling. Chondrocyte proliferation in the growth plate was observed using cresyl violet dye. In addition, we analyzed the expressions of BMP-2 and IGF-1 using immunohistochemistry. Eucommia ulmoides extract significantly increased longitudinal bone growth rate and growth plate height in adolescent female rats. In the immunohistochemical study, E. ulmoides markedly increased BMP-2 and IGF-1 expressions in the proliferative and hypertrophic zones. In conclusion, E. ulmoides increased longitudinal bone growth rate by promoting chondrogenesis in the growth plate and the levels of BMP-2 and IGF-1. Eucommia ulmoides could be helpful for increasing bone growth in children who have growth retardation. PMID:25087723

  6. Growth rates of the population in a branching Brownian motion with an inhomogeneous breeding potential

    CERN Document Server

    Berestycki, Julien; Harris, John W; Harris, Simon C; Roberts, Matthew I

    2012-01-01

    We consider a branching particle system where each particle moves as an independent Brownian motion and breeds at a rate proportional to its distance from the origin raised to the power $p$, for $p\\in[0,2)$. The asymptotic behaviour of the right-most particle for this system is already known; in this article we give large deviations probabilities for particles following "difficult" paths, growth rates along "easy" paths, the total population growth rate, and we derive the optimal paths which particles must follow to achieve this growth rate.

  7. A biphasic endothelial stress-survival mechanism regulates the cellular response to vascular endothelial growth factor A

    International Nuclear Information System (INIS)

    Vascular endothelial growth factor A (VEGF-A) is an essential cytokine that regulates endothelial function and angiogenesis. VEGF-A binding to endothelial receptor tyrosine kinases such as VEGFR1 and VEGFR2 triggers cellular responses including survival, proliferation and new blood vessel sprouting. Increased levels of a soluble VEGFR1 splice variant (sFlt-1) correlate with endothelial dysfunction in pathologies such as pre-eclampsia; however the cellular mechanism(s) underlying the regulation and function of sFlt-1 are unclear. Here, we demonstrate the existence of a biphasic stress response in endothelial cells, using serum deprivation as a model of endothelial dysfunction. The early phase is characterized by a high VEGFR2:sFlt-1 ratio, which is reversed in the late phase. A functional consequence is a short-term increase in VEGF-A-stimulated intracellular signaling. In the late phase, sFlt-1 is secreted and deposited at the extracellular matrix. We hypothesized that under stress, increased endothelial sFlt-1 levels reduce VEGF-A bioavailability: VEGF-A treatment induces sFlt-1 expression at the cell surface and VEGF-A silencing inhibits sFlt-1 anchorage to the extracellular matrix. Treatment with recombinant sFlt-1 inhibits VEGF-A-stimulated in vitro angiogenesis and sFlt-1 silencing enhances this process. In this response, increased VEGFR2 levels are regulated by the phosphatidylinositol-3-kinase and PKB/Akt signaling pathways and increased sFlt-1 levels by the ERK1/2 signaling pathway. We conclude that during serum withdrawal, cellular sensing of environmental stress modulates sFlt-1 and VEGFR2 levels, regulating VEGF-A bioavailability and ensuring cell survival takes precedence over cell proliferation and migration. These findings may underpin an important mechanism contributing to endothelial dysfunction in pathological states. -- Highlights: ► Endothelial cells mount a stress response under conditions of low serum. ► Endothelial VEGFR levels are

  8. A biphasic endothelial stress-survival mechanism regulates the cellular response to vascular endothelial growth factor A

    Energy Technology Data Exchange (ETDEWEB)

    Latham, Antony M.; Odell, Adam F. [Endothelial Cell Biology Unit, School of Molecular and Cellular Biology, University of Leeds, Leeds LS2 9JT (United Kingdom); Mughal, Nadeem A. [Leeds Vascular Institute, Leeds General Infirmary, Great George Street, Leeds LS1 3EX (United Kingdom); Issitt, Theo; Ulyatt, Clare; Walker, John H. [Endothelial Cell Biology Unit, School of Molecular and Cellular Biology, University of Leeds, Leeds LS2 9JT (United Kingdom); Homer-Vanniasinkam, Shervanthi [Leeds Vascular Institute, Leeds General Infirmary, Great George Street, Leeds LS1 3EX (United Kingdom); Ponnambalam, Sreenivasan, E-mail: s.ponnambalam@leeds.ac.uk [Endothelial Cell Biology Unit, School of Molecular and Cellular Biology, University of Leeds, Leeds LS2 9JT (United Kingdom)

    2012-11-01

    Vascular endothelial growth factor A (VEGF-A) is an essential cytokine that regulates endothelial function and angiogenesis. VEGF-A binding to endothelial receptor tyrosine kinases such as VEGFR1 and VEGFR2 triggers cellular responses including survival, proliferation and new blood vessel sprouting. Increased levels of a soluble VEGFR1 splice variant (sFlt-1) correlate with endothelial dysfunction in pathologies such as pre-eclampsia; however the cellular mechanism(s) underlying the regulation and function of sFlt-1 are unclear. Here, we demonstrate the existence of a biphasic stress response in endothelial cells, using serum deprivation as a model of endothelial dysfunction. The early phase is characterized by a high VEGFR2:sFlt-1 ratio, which is reversed in the late phase. A functional consequence is a short-term increase in VEGF-A-stimulated intracellular signaling. In the late phase, sFlt-1 is secreted and deposited at the extracellular matrix. We hypothesized that under stress, increased endothelial sFlt-1 levels reduce VEGF-A bioavailability: VEGF-A treatment induces sFlt-1 expression at the cell surface and VEGF-A silencing inhibits sFlt-1 anchorage to the extracellular matrix. Treatment with recombinant sFlt-1 inhibits VEGF-A-stimulated in vitro angiogenesis and sFlt-1 silencing enhances this process. In this response, increased VEGFR2 levels are regulated by the phosphatidylinositol-3-kinase and PKB/Akt signaling pathways and increased sFlt-1 levels by the ERK1/2 signaling pathway. We conclude that during serum withdrawal, cellular sensing of environmental stress modulates sFlt-1 and VEGFR2 levels, regulating VEGF-A bioavailability and ensuring cell survival takes precedence over cell proliferation and migration. These findings may underpin an important mechanism contributing to endothelial dysfunction in pathological states. -- Highlights: Black-Right-Pointing-Pointer Endothelial cells mount a stress response under conditions of low serum. Black

  9. Microalgal growth with intracellular phosphorus for achieving high biomass growth rate and high lipid/triacylglycerol content simultaneously.

    Science.gov (United States)

    Wu, Yin-Hu; Yu, Yin; Hu, Hong-Ying

    2015-09-01

    Nutrient deprivation is a commonly-used trigger for microalgal lipid accumulation, but its adverse impact on microalgal growth seems to be inevitable. In this study, Scenedesmus sp. LX1 was found to show similar physiological and biochemical variation under oligotrophic and eutrophic conditions during growth with intracellular phosphorus. Under both conditions microalgal chlorophyll content and photosynthesis activity was stable during this growth process, leading to significant increase of single cell weight and size. Therefore, while algal density growth rate dropped significantly to below 1.0 × 10(5)cells mL(-1) d(-1) under oligotrophic condition, the biomass dry weight growth rate still maintained about 40 mg L(-1) d(-1). Meanwhile, the lipid content in biomass and triacylglycerols (TAGs) content in lipids increased significantly to about 35% and 65%, respectively. Thus, high biomass growth rate and high lipid/TAG content were achieved simultaneously at the late growth phase with intracellular phosphorus. Besides, microalgal biomass produced was rich in carbohydrate with low protein content. PMID:26056779

  10. Study of failures in a rabbit line selected for growth rate

    OpenAIRE

    C. Naturil-Alfonso; R. Lavara; Millán , P.; Rebollar, P.G.; J.S. Vicente; F. Marco-Jiménez

    2016-01-01

    Selection for growth rate is negatively related with reproductive fitness. The aim of this work was to analyse the causes of fertility failure in rabbit does selected for growth rate and characterised for reproductive deficiencies (line R). In the experiment, 82 does were divided into 2 groups: naturally mated (NM) and artificially inseminated (AI), to relate luteinizing hormone (LH) concentration with ovulation induction and pregnancy rate by laparoscopic determination. Additionally, in 38 o...

  11. Rate of Head Circumference Growth as a Function of Autism Diagnosis and History of Autistic Regression

    OpenAIRE

    WEBB, SARA JANE; Nalty, Theresa; Munson, Jeff; Brock, Catherine; Abbott, Robert; Dawson, Geraldine

    2007-01-01

    Several reports indicate that autism spectrum disorder (ASD) is associated with increased rate of head growth in early childhood. Increased rate of growth may index aberrant processes during early development, may precede the onset of symptoms, and may predict severity of the disease course. We examined rate of change in occipitofrontal circumference measurements (abstracted from medical records) in 28 boys with ASD and in 8 boys with developmental delay without autism from birth to age 36 mo...

  12. The effects of temperature and NaCl concentration on tetragonal lysozyme face growth rates

    Science.gov (United States)

    Forsythe, Elizabeth; Pusey, Marc Lee

    1994-01-01

    Measurements were made of the (110) and (101) face growth rates of the tetragonal form of hen egg white lysozyme at 0.1M sodium acetate buffer, pH 4.0, from 4 to 22 C and with 3.0%, 5.0%, and 7.0% NaCl used as the precipitating salt. The data were collected at supersaturation ratios ranging from approximately 4 to approximately 63. Both decreasing temperature and increasing salt concentrations shifted plots of the growth rate versus C/C(sat) to the right, i.e. higher supersaturations were required for comparable growth rates. The observed trends in the growth data are counter to those expected from the solubility data. If tetragonal lysozyme crystal growth is by addition of ordered aggregates from the solution, then the observed growth data could be explained as a result of the effects of lowered temperature and increased salt concentration on the kinetics and equilibrium processes governing protein-protein interactions in solution. The data indicate that temperature would be a more tractable means of controlling the growth rate for tetragonal lysozyme crystals contrary to the usual practice in, e.g., vapor diffusion protein crystal growth, where both the precipitant and protein concentrations are simultaneously increased. However, the available range for control is dependent upon the protein concentration, with the greatest growth rate control being at the lower concentration.

  13. A NOVEL PARAMETER FOR EVALUATING THE FATIGUE CRACK GROWTH RATE IN CARBON STEELS

    Institute of Scientific and Technical Information of China (English)

    X.S.Wang; S.Q.Zhu; N.Kawagoishi; H.Nisitani

    2001-01-01

    A novel parameter is suggested for evaluating the fatigue crack growth rate in carbonsteels.Fatigue crack propagation tests of an annealed 0.42% carbon steel were carriedout under different conditions to investigate the relationship between this dominatingparameter and the crack opening displacement (COD).A new equation of fatiguecrack growth rate is formulated in terms of the suggested parameter.The physicalmeanings of the material parameters in this equation are explored experimentally.Considering the relation of crack growth and deformation properties,a simple andapplicable method is proposed to evaluate the fatigue crack growth rate.It is alsoobserved that the material parameters in the fatigue crack growth rate equation ofcarbon steels are related linearly to the material strength.The results are in a goodagreement with experimental results.

  14. Bilateral Trade and SEE–Eurozone Countries Growth Rate Alignment

    Directory of Open Access Journals (Sweden)

    Valerija Botrić

    2016-06-01

    Full Text Available The aim of the paper is to explore the role of trade in aligning the synchronisation patterns between the South Eastern European (see countries – Albania, Bosnia and Herzegovina, Bulgaria, Croatia, FYR of Macedonia, Kosovo, Montenegro, Romania and Serbia – and members of the euro area. More precisely, we investigate whether bilateral trade flows affect output synchronisation between the euro area countries and see countries and compare trade-synchronisation patterns between the see countries and new member states that have not yet introduced the euro (NMS. The results show that the levels of output similarities between the see countries and NMS are different and that the see countries exhibit lower output correlation with the euro area members than the NMS. Exploring the role of trade in aligning growth patterns has in some cases found positive effects, much stronger for the see countries, which have lower trade intensity levels. We argue that the reason for these results is related to the fact that other factors could be dominant in the NMS countries (policy measures alignment within the EU, while for the see countries only trade relationships had the opportunity to exert noticeable effects in the analysed period.

  15. Anthropogenic and biophysical contributions to increasing atmospheric CO2 growth rate and airborne fraction

    Directory of Open Access Journals (Sweden)

    C. Le Quéré

    2008-11-01

    Full Text Available We quantify the relative roles of natural and anthropogenic influences on the growth rate of atmospheric CO2 and the CO2 airborne fraction, considering both interdecadal trends and interannual variability. A combined ENSO-Volcanic Index (EVI relates most (~75% of the interannual variability in CO2 growth rate to the El-Niño-Southern-Oscillation (ENSO climate mode and volcanic activity. Analysis of several CO2 data sets with removal of the EVI-correlated component confirms a previous finding of a detectable increasing trend in CO2 airborne fraction (defined using total anthropogenic emissions including fossil fuels and land use change over the period 1959–2006, at a proportional growth rate 0.24% y−1 with probability ~0.9 of a positive trend. This implies that the atmospheric CO2 growth rate increased slightly faster than total anthropogenic CO2 emissions. To assess the combined roles of the biophysical and anthropogenic drivers of atmospheric CO2 growth, the increase in the CO2 growth rate (1.9% y−1 over 1959–2006 is expressed as the sum of the growth rates of four global driving factors: population (contributing +1.7% y−1; per capita income (+1.8% y−1; the total carbon intensity of the global economy (−1.7% y−1; and airborne fraction (averaging +0.2% y−1 with strong interannual variability. The first three of these factors, the anthropogenic drivers, have therefore dominated the last, biophysical driver as contributors to accelerating CO2 growth. Together, the recent (post-2000 increase in growth of per capita income and decline in the negative growth (improvement in the carbon intensity of the economy will drive a significant further acceleration in the CO2 growth rate over coming decades, unless these recent trends reverse.

  16. Population Growth Rate, Life Expectancy and Pension Program Improvement in China

    OpenAIRE

    Yang, Zaigui

    2008-01-01

    Applying an overlapping-generations model with lifetime uncertainty, we examine in this paper China’s partially funded public pension system. The findings show that the individual contribution rate does not affect the capital-labor ratio but the firm contribution rate does. The optimal firm contribution rate depends on the capital share of income, social discount factor, survival probability, and population growth rate. The simulation results indicate that the optimal firm contribution rate r...

  17. The effect of real exchange rate misalignment on economic growth in South Africa / S. Zwedala.

    OpenAIRE

    Zwedala, Sibulele

    2013-01-01

    The growth performance of the South African economy over the past two and a half decades has been disappointing. The economy has not reached the high growth rates of the 1960s, which is desperately needed to alleviate poverty in the country. While the sources of growth have been a subject of much debate, recently the notion that the Real Exchange Rate (RER) level of a country matters for growth has attracted attention. While it is generally expected that the value of the currency should not r...

  18. Growth kinetics of cellular precipitation in a Mg-8.5Al-0.5Zn-0.2Mn (wt.%) alloy

    International Nuclear Information System (INIS)

    Research highlights: → The growth kinetics of lamellar spacing follows the behavior predicted by Turnbull theory. → The growth kinetics of cellular precipitation is a process controlled by grain boundary diffusion. → The presence of two types of morphology for cellular precipitation depends on the aging temperature. → The highest hardness peak is associated to a fine continuous precipitation at the lowest temperature. → The lowest hardness is attributed to the fast coarsening process of both precipitations. - Abstract: Microstructural evolution and growth kinetics were studied in an isothermally aged Mg-8.5Al-0.5Zn-0.2Mn (wt.%) alloy by means of X-ray diffraction, scanning electron microscopy, Vickers hardness measurements and transmission electron microscopy. Specimens were solution-treated and then aged at 373, 473 and 573 K for different time period. The characterization results indicated the presence of both continuous and discontinuous precipitations of the Mg17Al12-γ phase in a Mg-rich matrix. The discontinuous or cellular precipitation was present with a lamellar structure, and the growth kinetics was evaluated using the Johnson-Mehl-Avrami-Kolmogorov equation analysis, which gives a time exponent close to 1. This value confirms that cellular precipitation takes place on the saturation sites corresponding to grain boundaries. In addition, the activation energy for cellular precipitation was determined to be about 64.6 kJ mol-1. This also indicates a grain boundary diffusion process. The variation of cellular spacing with temperature follows the behavior expected by Turnbull theory. The highest hardness peak corresponded to the lowest aging temperature and it is associated with a fine continuous precipitation; while the lowest hardness peak was detected at the highest aging temperature and it is attributed to the rapid coarsening process of both precipitations.

  19. Growth kinetics of cellular precipitation in a Mg-8.5Al-0.5Zn-0.2Mn (wt.%) alloy

    Energy Technology Data Exchange (ETDEWEB)

    Contreras-Piedras, Edgar [Instituto Politecnico Nacional-ESIQIE-DIMM-ESFM, Apartado Postal 118-430, Admon. GAM, Mexico, D.F. 07051 (Mexico); Esquivel-Gonzalez, Ramon [Universidad del Valle de Mexico, Depto. Ingenierias, Paseo de las Aves 1, Col. San Mateo Nopala, Lomas Verdes, Naucalpan de Juarez, Edo. Mex. 53220 (Mexico); Lopez-Hirata, Victor M.; Saucedo-Munoz, M.L.; Paniagua-Mercado, Ana M. [Instituto Politecnico Nacional-ESIQIE-DIMM-ESFM, Apartado Postal 118-430, Admon. GAM, Mexico, D.F. 07051 (Mexico); Dorantes-Rosales, Hector J., E-mail: hectordorantes@yahoo.com [Instituto Politecnico Nacional-ESIQIE-DIMM-ESFM, Apartado Postal 118-430, Admon. GAM, Mexico, D.F. 07051 (Mexico)

    2010-11-15

    Research highlights: {yields} The growth kinetics of lamellar spacing follows the behavior predicted by Turnbull theory. {yields} The growth kinetics of cellular precipitation is a process controlled by grain boundary diffusion. {yields} The presence of two types of morphology for cellular precipitation depends on the aging temperature. {yields} The highest hardness peak is associated to a fine continuous precipitation at the lowest temperature. {yields} The lowest hardness is attributed to the fast coarsening process of both precipitations. - Abstract: Microstructural evolution and growth kinetics were studied in an isothermally aged Mg-8.5Al-0.5Zn-0.2Mn (wt.%) alloy by means of X-ray diffraction, scanning electron microscopy, Vickers hardness measurements and transmission electron microscopy. Specimens were solution-treated and then aged at 373, 473 and 573 K for different time period. The characterization results indicated the presence of both continuous and discontinuous precipitations of the Mg{sub 17}Al{sub 12}-{gamma} phase in a Mg-rich matrix. The discontinuous or cellular precipitation was present with a lamellar structure, and the growth kinetics was evaluated using the Johnson-Mehl-Avrami-Kolmogorov equation analysis, which gives a time exponent close to 1. This value confirms that cellular precipitation takes place on the saturation sites corresponding to grain boundaries. In addition, the activation energy for cellular precipitation was determined to be about 64.6 kJ mol{sup -1}. This also indicates a grain boundary diffusion process. The variation of cellular spacing with temperature follows the behavior expected by Turnbull theory. The highest hardness peak corresponded to the lowest aging temperature and it is associated with a fine continuous precipitation; while the lowest hardness peak was detected at the highest aging temperature and it is attributed to the rapid coarsening process of both precipitations.

  20. Comparing the epidermal growth factor interaction with four different cell lines: intriguing effects imply strong dependency of cellular context.

    Directory of Open Access Journals (Sweden)

    Hanna Björkelund

    Full Text Available The interaction of the epidermal growth factor (EGF with its receptor (EGFR is known to be complex, and the common over-expression of EGF receptor family members in a multitude of tumors makes it important to decipher this interaction and the following signaling pathways. We have investigated the affinity and kinetics of (125I-EGF binding to EGFR in four human tumor cell lines, each using four culturing conditions, in real time by use of LigandTracer®.Highly repeatable and precise measurements show that the overall apparent affinity of the (125I-EGF - EGFR interaction is greatly dependent on cell line at normal culturing conditions, ranging from K(D ≈ 200 pM on SKBR3 cells to K(D≈8 nM on A431 cells. The (125I-EGF - EGFR binding curves (irrespective of cell line have strong signs of multiple simultaneous interactions. Furthermore, for the cell lines A431 and SKOV3, gefitinib treatment increases the (125I-EGF - EGFR affinity, in particular when the cells are starved. The (125I-EGF - EGFR interaction on cell line U343 is sensitive to starvation while as on SKBR3 it is insensitive to gefitinib and starvation.The intriguing pattern of the binding characteristics proves that the cellular context is important when deciphering how EGF interacts with EGFR. From a general perspective, care is advisable when generalizing ligand-receptor interaction results across multiple cell-lines.

  1. Lower-leg growth rates in children with asthma during treatment with ciclesonide and fluticasone propionate

    DEFF Research Database (Denmark)

    Lone, Agertoft; Søren, Pedersen

    2009-01-01

    Measurement of short-term lower-leg growth rate in children by knemometry has become established as an integral part of the available measures of systemic activity of inhaled corticosteroids (ICS) in children. The aim of this study was to compare the effects of the novel ICS ciclesonide (CIC) and...... no significant effect on lower-leg growth rate in children aged 6-12 yr with mild asthma. In contrast, a similar dose of FP significantly reduced lower-leg growth rate compared with placebo and CIC....

  2. Growth rate enhancement of free-electron laser by two consecutive wigglers with axial magnetic field

    Indian Academy of Sciences (India)

    A Hasanbeigi; A Farhadian; E Khademi Bidhendi

    2014-06-01

    The operative mechanism for a free-electron laser (FEL) with two consecutive helical wigglers having opposite circular polarization in the presence of an axial magnetic field is proposed and analysed. With the help of fluid theory, a tenth-degree polynomial dispersion equation for electromagnetic and space-charge waves is derived. The results are used to illustrate and discuss the dependence of growth rate on different system parameters. Finally, it is shown that for the same system parameters the growth rate of the proposed structure is more than the growth rate of instability in a conventional FEL.

  3. The effect of rumen content transfer on rate of bacteria and protozoa growth

    International Nuclear Information System (INIS)

    The aims the experiment wants to know the benefit of rate of microbial protein in rumen content and to complete the information that isolates is useful for ruminant animals feed. The result indicated that buffaloes from East Nusa Tenggara is the best when they are used as donor rumen transfer making isolate. When rumen of ongole cattle generation was mixed in rumen content of buffaloes from East Nusa Tenggara and incubated 48 h, the rate of bacteria cell growth is better than rate of protozoa cell growth comparing to the other animals. The values are 30.99 mg/h/100 ml and 24.92 mg.h/100 ml respectively. The results of isolate selection in 48 h incubation indicated that treatment F is the best. The results rates of bacteria cell growth and rate of protozoa's cell growth are 26.96 mg/h/100 ml and 2.53 mg/h/100 respectively. The result of in vitro study indicated that pH and ammonia concentration support the rate of bacteria cell growth and do not cause the toxicity of microbes and animal . The rate of bacteria cell growth on D treatment is significant to A,B, and C treatments. The values are 21.44 mg/h/100 ml. 7.99; 13.13; and 13.38 mg/h/100 ml respectively. The result rates of protozoa's cell growth tends lower than rates of bacteria cell. The overall conclusion is a lower or a higher rate of microorganism cell growth depends on the environment condition. (author)

  4. Assessment of the inhibition of Dengue virus infection by carrageenan via real-time monitoring of cellular oxygen consumption rates within a microfluidic device

    Science.gov (United States)

    Huang, Shih-Hao; Lin, Yi-Syun; Wu, Chih-Wei; Wu, Chang-Jer

    2014-01-01

    A microfluidic device combined with a light modulation system was developed to assess the inhibitory effect of carrageenan on Dengue virus (DENV) infection via real-time monitoring of cellular oxygen consumption rates (OCRs). Measuring cellular OCRs, which can reflect cellular metabolic activity, enabled us to monitor the process of viral infection in real time and to rapidly determine the antiviral activity of potential drugs/chemical compounds. The time variation of the cellular OCR of single cells that were infected in situ by DENV at different multiplicity of infection (m.o.i.) values was first successfully measured within a microfluidic device. The influence of the timing of carrageenan treatment on DENV infection was then examined by real-time monitoring of cellular OCRs in three groups. Cells that were pre-treated with carrageenan and then infected with DENV served as a pre-treatment group, cells to which carrageenan was added simultaneously with DENV served as a virucide group, and cells that were pre-infected with DENV and then treated with carrageenan served as a post-treatment group. By monitoring cellular OCRs, we could rapidly evaluate the inhibitory effect of carrageenan on DENV infection, obtaining a result within 7 h and showing that carrageenan had strong and effective anti-DENV activity in the three groups. In particular, a strong inhibitory effect was observed in the virucide group. Moreover, once the virus enters host cells in the post-treatment group, the immediate treatment with carrageenan for the infected cells has higher efficiency of antiviral activity. Our proposed platform enables to perform time-course or dose-response measurements of changes in cellular metabolic activity caused by diseases, chemical compounds, and drugs via monitoring of the cellular OCR, with rapid and real-time detection. This approach provides the potential to study a wide range of biological applications in cell-based biosensing, toxicology, and drug discovery

  5. Patient-derived xenograft (PDX) tumors increase growth rate with time

    Science.gov (United States)

    Pearson, Alexander T.; Finkel, Kelsey A.; Warner, Kristy A.; Nör, Felipe; Tice, David; Martins, Manoela D.; Jackson, Trachette L.; Nör, Jacques E.

    2016-01-01

    Patient-derived xenograft (PDX) models are frequently used for translational cancer research, and are assumed to behave consistently as the tumor ages. However, growth rate constancy as a function of time is unclear. Notably, variable PDX growth rates over time might have implications for the interpretation of translational studies. We characterized four PDX models through several in vivo passages from primary human head and neck squamous cell carcinoma and salivary gland adenoid cystic carcinoma. We developed a mathematical approach to merge growth data from different passages into a single measure of relative tumor volume normalized to study initiation size. We analyzed log-relative tumor volume increase with linear mixed effect models. Two oral pathologists analyzed the PDX tissues to determine if histopathological feature changes occurred over in vivo passages. Tumor growth rate increased over time. This was determined by repeated measures linear regression statistical analysis in four different PDX models. A quadratic statistical model for the temporal effect predicted the log-relative tumor volume significantly better than a linear time effect model. We found a significant correlation between passage number and histopathological features of higher tumor grade. Our mathematical treatment of PDX data allows statistical analysis of tumor growth data over long periods of time, including over multiple passages. Non-linear tumor growth in our regression models revealed the exponential growth rate increased over time. The dynamic tumor growth rates correlated with quantifiable histopathological changes that related to passage number in multiple types of cancer. PMID:26783960

  6. Daily changes in temperature, not the circadian clock, regulate growth rate in Brachypodium distachyon.

    Directory of Open Access Journals (Sweden)

    Dominick A Matos

    Full Text Available Plant growth is commonly regulated by external cues such as light, temperature, water availability, and internal cues generated by the circadian clock. Changes in the rate of growth within the course of a day have been observed in the leaves, stems, and roots of numerous species. However, the relative impact of the circadian clock on the growth of grasses has not been thoroughly characterized. We examined the influence of diurnal temperature and light changes, and that of the circadian clock on leaf length growth patterns in Brachypodium distachyon using high-resolution time-lapse imaging. Pronounced changes in growth rate were observed under combined photocyles and thermocycles or with thermocycles alone. A considerably more rapid growth rate was observed at 28°C than 12°C, irrespective of the presence or absence of light. In spite of clear circadian clock regulated gene expression, plants exhibited no change in growth rate under conditions of constant light and temperature, and little or no effect under photocycles alone. Therefore, temperature appears to be the primary cue influencing observed oscillations in growth rate and not the circadian clock or photoreceptor activity. Furthermore, the size of the leaf meristem and final cell length did not change in response to changes in temperature. Therefore, the nearly five-fold difference in growth rate observed across thermocycles can be attributed to proportionate changes in the rate of cell division and expansion. A better understanding of the growth cues in B. distachyon will further our ability to model metabolism and biomass accumulation in grasses.

  7. Crack growth rate in core shroud horizontal welds using two models for a BWR

    International Nuclear Information System (INIS)

    Highlights: • Two models were used to predict SCC growth rate in a core shroud of a BWR. • A weld residual stress distribution with 30% stress relaxation by neutron was used. • Agreement is shown between the measurements of SCC growth rate and the predictions. • Slip–oxidation model is better at low fluences and empirical model at high fluences. - Abstract: An empirical crack growth rate correlation model and a predictive model based on the slip–oxidation mechanism for Stress Corrosion Cracking (SCC) were used to calculate the crack growth rate in a BWR core shroud. In this study, the crack growth rate was calculated by accounting for the environmental factors related to aqueous environment, neutron irradiation to high fluence and the complex residual stress conditions resulting from welding. In estimating the SCC behavior the crack growth measurements data from a Boiling Water Reactor (BWR) plant are referred to, and the stress intensity factor vs crack depth throughout thickness is calculated using a generic weld residual stress distribution for a core shroud, with a 30% stress relaxation induced by neutron irradiation. Quantitative agreement is shown between the measurements of SCC growth rate and the predictions of the slip–oxidation mechanism model for relatively low fluences (5 × 1024 n/m2), and the empirical model predicted better the SCC growth rate than the slip–oxidation model for high fluences (>1 × 1025 n/m2). The relevance of the models predictions for SCC growth rate behavior depends on knowing the model parameters

  8. Consistent fractionation of 13C in nature and in the laboratory: Growth-rate effects in some haptophyte algae

    Science.gov (United States)

    Bidigare, Robert R.; Fluegge, Arnim; Freeman, Katherine H.; Hanson, Kristi L.; Hayes, John M.; Hollander, David; Jasper, John P.; King, Linda L.; Laws, Edward A.; Milder, Jeffrey; Millero, Frank J.; Pancost, Richard; Popp, Brian N.; Steinberg, Paul A.; Wakeham, Stuart G.

    1997-06-01

    The carbon isotopic fractionation accompanying formation of biomass by alkenone-producing algae in natural marine environments varies systematically with the concentration of dissolved phosphate. Specifically, if the fractionation is expressed by єP ≈ δe - δp, where δe and δp are the δ13C values for dissolved CO2 and for algal biomass (determined by isotopic analysis of C37 alkadienones), respectively, and if Ce is the concentration of dissolved CO2, μmol kg-1, then b = 38 + 160*[PO4], where [PO4] is the concentration of dissolved phosphate, μM, and b = (25 - єp)Ce. The correlation found between b and [PO4] is due to effects linking nutrient levels to growth rates and cellular carbon budgets for alkenone-containing algae, most likely by trace-metal limitations on algal growth. The relationship reported here is characteristic of 39 samples (r2 = 0.95) from the Santa Monica Basin (six different times during the annual cycle), the equatorial Pacific (boreal spring and fall cruises as well as during an iron-enrichment experiment), and the Peru upwelling zone. Points representative of samples from the Sargasso Sea ([PO4] ≤ 0.1 μM) fall above the b = f[PO4] line. Analysis of correlations expected between μ (growth rate), єp, and Ce shows that, for our entire data set, most variations in єp result from variations in μ rather than Ce. Accordingly, before concentrations of dissolved CO2 can be estimated from isotopic fractionations, some means of accounting for variations in growth rate must be found, perhaps by drawing on relationships between [PO4] and Cd/Ca ratios in shells of planktonic foraminifera.

  9. Ab initio determination of the instability growth rate of warm dense beryllium-deuterium interface

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Cong; Zhang, Ping, E-mail: zhang-ping@iapcm.ac.cn [Institute of Applied Physics and Computational Mathematics, P.O. Box 8009, Beijing 100088 (China); Center for Applied Physics and Technology, Peking University, Beijing 100871 (China); Li, Zi; Li, DaFang [Institute of Applied Physics and Computational Mathematics, P.O. Box 8009, Beijing 100088 (China)

    2015-10-15

    Accurate knowledge about the interfacial unstable growth is of great importance in inertial confinement fusion. During implosions, the deuterium-tritium capsule is driven by laser beams or X-rays to access the strongly coupled and partially degenerated warm dense matter regime. At this stage, the effects of dissipative processes, such as diffusion and viscosity, have significant impact on the instability growth rates. Here, we present ab initio molecular dynamics simulations to determine the equations of state and the transport coefficients. Several models are used to estimate the reduction in the growth rate dispersion curves of Rayleigh-Taylor and Richtmyer-Meshkov instabilities with considering the presence of these dissipative effects. We show that these instability growth rates are effectively reduced when considering diffusion. The findings provide significant insights into the microscopic mechanism of the instability growth at the ablator-fuel interface and will refine the models used in the laser-driven hydrodynamic instability experiments.

  10. Ab initio determination of the instability growth rate of warm dense beryllium-deuterium interface

    Science.gov (United States)

    Wang, Cong; Li, Zi; Li, DaFang; Zhang, Ping

    2015-10-01

    Accurate knowledge about the interfacial unstable growth is of great importance in inertial confinement fusion. During implosions, the deuterium-tritium capsule is driven by laser beams or X-rays to access the strongly coupled and partially degenerated warm dense matter regime. At this stage, the effects of dissipative processes, such as diffusion and viscosity, have significant impact on the instability growth rates. Here, we present ab initio molecular dynamics simulations to determine the equations of state and the transport coefficients. Several models are used to estimate the reduction in the growth rate dispersion curves of Rayleigh-Taylor and Richtmyer-Meshkov instabilities with considering the presence of these dissipative effects. We show that these instability growth rates are effectively reduced when considering diffusion. The findings provide significant insights into the microscopic mechanism of the instability growth at the ablator-fuel interface and will refine the models used in the laser-driven hydrodynamic instability experiments.

  11. Ab initio determination of the instability growth rate of warm dense beryllium-deuterium interface

    International Nuclear Information System (INIS)

    Accurate knowledge about the interfacial unstable growth is of great importance in inertial confinement fusion. During implosions, the deuterium-tritium capsule is driven by laser beams or X-rays to access the strongly coupled and partially degenerated warm dense matter regime. At this stage, the effects of dissipative processes, such as diffusion and viscosity, have significant impact on the instability growth rates. Here, we present ab initio molecular dynamics simulations to determine the equations of state and the transport coefficients. Several models are used to estimate the reduction in the growth rate dispersion curves of Rayleigh-Taylor and Richtmyer-Meshkov instabilities with considering the presence of these dissipative effects. We show that these instability growth rates are effectively reduced when considering diffusion. The findings provide significant insights into the microscopic mechanism of the instability growth at the ablator-fuel interface and will refine the models used in the laser-driven hydrodynamic instability experiments

  12. A panel data investigation of real exchange rate misalignment and growth

    Directory of Open Access Journals (Sweden)

    Flávio Vilela Vieira

    2012-09-01

    Full Text Available The paper investigates the role of real exchange rate misalignment on long-run growth for a set of ninety countries using time series data from 1980 to 2004. We first estimate a panel data model (fixed and random effects for the real exchange rate in order to produce estimates of the equilibrium real exchange rate and this is then used to construct measures of real exchange rate misalignment. We provide an alternative set of estimates of RER misalignment using panel cointegration methods. The results for the two-step System GMM panel growth models indicate that the coefficients for real exchange rate misalignment are positive for different model specification and samples, which means that a more depreciated (appreciated real exchange rate helps (harms long-run growth. The estimated coefficients are higher for developing and emerging countries.

  13. Effects of Phlomis umbrosa Root on Longitudinal Bone Growth Rate in Adolescent Female Rats.

    Science.gov (United States)

    Lee, Donghun; Kim, Young-Sik; Song, Jungbin; Kim, Hyun Soo; Lee, Hyun Jung; Guo, Hailing; Kim, Hocheol

    2016-01-01

    This study aimed to investigate the effects of Phlomis umbrosa root on bone growth and growth mediators in rats. Female adolescent rats were administered P. umbrosa extract, recombinant human growth hormone or vehicle for 10 days. Tetracycline was injected intraperitoneally to produce a glowing fluorescence band on the newly formed bone on day 8, and 5-bromo-2'-deoxyuridine was injected to label proliferating chondrocytes on days 8-10. To assess possible endocrine or autocrine/paracrine mechanisms, we evaluated insulin-like growth factor-1 (IGF-1), insulin-like growth factor binding protein-3 (IGFBP-3) or bone morphogenetic protein-2 (BMP-2) in response to P. umbrosa administration in either growth plate or serum. Oral administration of P. umbrosa significantly increased longitudinal bone growth rate, height of hypertrophic zone and chondrocyte proliferation of the proximal tibial growth plate. P. umbrosa also increased serum IGFBP-3 levels and upregulated the expressions of IGF-1 and BMP-2 in growth plate. In conclusion, P. umbrosa increases longitudinal bone growth rate by stimulating proliferation and hypertrophy of chondrocyte with the increment of circulating IGFBP-3. Regarding the immunohistochemical study, the effect of P. umbrosa may also be attributable to upregulation of local IGF-1 and BMP-2 expressions in the growth plate, which can be considered as a GH dependent autocrine/paracrine pathway. PMID:27070559

  14. Effects of Phlomis umbrosa Root on Longitudinal Bone Growth Rate in Adolescent Female Rats

    Directory of Open Access Journals (Sweden)

    Donghun Lee

    2016-04-01

    Full Text Available This study aimed to investigate the effects of Phlomis umbrosa root on bone growth and growth mediators in rats. Female adolescent rats were administered P. umbrosa extract, recombinant human growth hormone or vehicle for 10 days. Tetracycline was injected intraperitoneally to produce a glowing fluorescence band on the newly formed bone on day 8, and 5-bromo-2′-deoxyuridine was injected to label proliferating chondrocytes on days 8–10. To assess possible endocrine or autocrine/paracrine mechanisms, we evaluated insulin-like growth factor-1 (IGF-1, insulin-like growth factor binding protein-3 (IGFBP-3 or bone morphogenetic protein-2 (BMP-2 in response to P. umbrosa administration in either growth plate or serum. Oral administration of P. umbrosa significantly increased longitudinal bone growth rate, height of hypertrophic zone and chondrocyte proliferation of the proximal tibial growth plate. P. umbrosa also increased serum IGFBP-3 levels and upregulated the expressions of IGF-1 and BMP-2 in growth plate. In conclusion, P. umbrosa increases longitudinal bone growth rate by stimulating proliferation and hypertrophy of chondrocyte with the increment of circulating IGFBP-3. Regarding the immunohistochemical study, the effect of P. umbrosa may also be attributable to upregulation of local IGF-1 and BMP-2 expressions in the growth plate, which can be considered as a GH dependent autocrine/paracrine pathway.

  15. Stress corrosion crack growth rate measurement in high temperature water using small precracked bend specimens

    International Nuclear Information System (INIS)

    The applicability of elastic-plastic fracture mechanics to stress corrosion crack growth rate measurements was studied. Several test series were performed on small elastic-plastically loaded SEN(B) specimens in high temperature water. One test was performed on a 25 mm C(T) specimen under linear-elastic loading. The tests on the SEN(B) specimens were performed using either rising displacement or a combination of rising and constant displacement loading. The test on the 25 mm C(T) specimen was performed using a combination of constant load and constant displacement. The studied materials were AISI 304 steel in sensitized, mill-annealed and irradiated conditions, AISI 316 in cold-worked condition, Inconel 82 and 182 weld metals in as-welded and thermally aged conditions and ferritic low activation steel F82H in tempered condition. The crack growth rate tests were performed in simulated pure BWR water and simulated BWR water with 10-100 ppb SO42- at 230-290 deg C. It was shown that intergranular stress corrosion cracking susceptibility can be determined using an elastic-plastic fracture mechanics approach. Fracture surface morphology in sensitized AISI 304 and welded AISI 321 steels depends on the applied loading rate in BWR water. The fracture surface morphology changes from transgranular to intergranular, when J-integral increase rate is decreased. However, extremely slow displacement rate is needed for the fracture surface morphology to be fully intergranular. Rising J results in transgranular stress corrosion cracking (or strain-induced corrosion cracking) also in the mill-annealed AISI 304 and 321 steels. Tests on irradiated AISI 304 steel showed that welding together with exposure to low neutron fluence in the BWR operating conditions results in a higher susceptibility to stress corrosion cracking than welding or irradiation alone. Ferritic low activation steel F82H (in tempered condition) is not susceptible to stress corrosion cracking under static loading

  16. Cellular Internalization of Fibroblast Growth Factor-12 Exerts Radioprotective Effects on Intestinal Radiation Damage Independently of FGFR Signaling

    Energy Technology Data Exchange (ETDEWEB)

    Nakayama, Fumiaki, E-mail: f_naka@nirs.go.jp [Advanced Radiation Biology Research Program, Research Center for Charged Particle Therapy, Chiba (Japan); Umeda, Sachiko [Advanced Radiation Biology Research Program, Research Center for Charged Particle Therapy, Chiba (Japan); Yasuda, Takeshi [Radiation Emergency Medicine Research Program, Research Center for Radiation Emergency Medicine, National Institute of Radiological Sciences, Chiba (Japan); Fujita, Mayumi [Advanced Radiation Biology Research Program, Research Center for Charged Particle Therapy, Chiba (Japan); Asada, Masahiro [Signaling Molecules Research Group, Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba (Japan); Meineke, Viktor [Bundeswehr Institute of Radiobiology affiliated to the University of Ulm, Munich (Germany); Imamura, Toru [Signaling Molecules Research Group, Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba (Japan); Imai, Takashi [Advanced Radiation Biology Research Program, Research Center for Charged Particle Therapy, Chiba (Japan)

    2014-02-01

    Purpose: Several fibroblast growth factors (FGFs) were shown to inhibit radiation-induced tissue damage through FGF receptor (FGFR) signaling; however, this signaling was also found to be involved in the pathogenesis of several malignant tumors. In contrast, FGF12 cannot activate any FGFRs. Instead, FGF12 can be internalized readily into cells using 2 cell-penetrating peptide domains (CPP-M, CPP-C). Therefore, this study focused on clarifying the role of FGF12 internalization in protection against radiation-induced intestinal injury. Methods and Materials: Each FGF or peptide was administered intraperitoneally to BALB/c mice in the absence of heparin 24 hours before or after total body irradiation with γ rays at 9 to 12 Gy. Several radioprotective effects were examined in the jejunum. Results: Administration of FGF12 after radiation exposure was as effective as pretreatment in significantly promoting intestinal regeneration, proliferation of crypt cells, and epithelial differentiation. Two domains, comprising amino acid residues 80 to 109 and 140 to 169 of FGF12B, were identified as being responsible for the radioprotective activity, so that deletion of both domains from FGF12B resulted in a reduction in activity. Interestingly, these regions included the CPP-M and CPP-C domains, respectively; however, CPP-C by itself did not show an antiapoptotic effect. In addition, FGF1, prototypic FGF, possesses a domain corresponding to CPP-M, whereas it lacks CPP-C, so the fusion of FGF1 with CPP-C (FGF1/CPP-C) enhanced cellular internalization and increased radioprotective activity. However, FGF1/CPP-C reduced in vitro mitogenic activity through FGFRs compared with FGF1, implying that FGFR signaling might not be essential for promoting the radioprotective effect of FGF1/CPP-C. In addition, internalized FGF12 suppressed the activation of p38α after irradiation, resulting in reduced radiation-induced apoptosis. Conclusions: These findings indicate that FGF12 can protect the

  17. Cellular Internalization of Fibroblast Growth Factor-12 Exerts Radioprotective Effects on Intestinal Radiation Damage Independently of FGFR Signaling

    International Nuclear Information System (INIS)

    Purpose: Several fibroblast growth factors (FGFs) were shown to inhibit radiation-induced tissue damage through FGF receptor (FGFR) signaling; however, this signaling was also found to be involved in the pathogenesis of several malignant tumors. In contrast, FGF12 cannot activate any FGFRs. Instead, FGF12 can be internalized readily into cells using 2 cell-penetrating peptide domains (CPP-M, CPP-C). Therefore, this study focused on clarifying the role of FGF12 internalization in protection against radiation-induced intestinal injury. Methods and Materials: Each FGF or peptide was administered intraperitoneally to BALB/c mice in the absence of heparin 24 hours before or after total body irradiation with γ rays at 9 to 12 Gy. Several radioprotective effects were examined in the jejunum. Results: Administration of FGF12 after radiation exposure was as effective as pretreatment in significantly promoting intestinal regeneration, proliferation of crypt cells, and epithelial differentiation. Two domains, comprising amino acid residues 80 to 109 and 140 to 169 of FGF12B, were identified as being responsible for the radioprotective activity, so that deletion of both domains from FGF12B resulted in a reduction in activity. Interestingly, these regions included the CPP-M and CPP-C domains, respectively; however, CPP-C by itself did not show an antiapoptotic effect. In addition, FGF1, prototypic FGF, possesses a domain corresponding to CPP-M, whereas it lacks CPP-C, so the fusion of FGF1 with CPP-C (FGF1/CPP-C) enhanced cellular internalization and increased radioprotective activity. However, FGF1/CPP-C reduced in vitro mitogenic activity through FGFRs compared with FGF1, implying that FGFR signaling might not be essential for promoting the radioprotective effect of FGF1/CPP-C. In addition, internalized FGF12 suppressed the activation of p38α after irradiation, resulting in reduced radiation-induced apoptosis. Conclusions: These findings indicate that FGF12 can protect the

  18. The Role Of Industry Structure, Costs, And Economic Spillovers In Determining State Employment Growth Rates

    OpenAIRE

    Mark D. Partridge; Rickman, Dan S.

    1996-01-01

    We examine differential state employment growth by appraising the relative effects of traditional cost factors versus knowledge and technology spillovers. One emphasis is the influence that industry composition has on employment growth. Traditional cost factors examined include wage rates, unionization, taxes, and government policies such as unemployment insurance and welfare programs. The results suggest that industry composition does influence growth, working through several different avenu...

  19. Cumulative Causation and Evolutionary Micro-Founded Technical Change. On the Determinants of Growth rate Differences

    OpenAIRE

    Patrick Llerena; André Lorentz

    2004-01-01

    We develop in this paper an alternative approach to the New Growth Theory to analyse growth rate differences among integrated economies. The model presented here considers economic growth as a disequilibrium process. It introduces in a cumulative causation framework, micro-founded process of technical change taking into account elements rooted in evolutionary and Neo-Austrian literature. We then attempt to open the ??Kaldor-Verdoorn law black-box?? using a microlevel modelling of industrial d...

  20. Influence of nitrogen supply on the area, mass and relative growth rate of maize leaf

    OpenAIRE

    OROKA FRANK OKE

    2015-01-01

    The study was aimed at assessing the effect of nitrogen application on the area, biomass and relative growth rate of maize leaf using a non-destructive method. Results showed high nitrogen supply, leaf area and leaf biomass.

  1. Enhancing product quantity by controlling the specific growth rate of Pichia pastoris expressing human serum albumin

    OpenAIRE

    Hama, Adel; Eyer, Kurt

    2011-01-01

    Establish a fed-batch process to culture a Pichia pastoris strain producing a recombinant protein (hSA), highlighting the relationship between the specific growth rate and the protein quality, as well as seeking for enhanced productivity.

  2. Growth rate of Usnea aurantiacoatra (Jacq.) Bory on Fildes Peninsula, Antarctica and its climatic background.

    Science.gov (United States)

    Li, Ying; Kromer, Bernd; Schukraft, Gerd; Bubenzer, Olaf; Huang, Man-Rong; Wang, Ze-Min; Bian, Lin-Gen; Li, Cheng-Sen

    2014-01-01

    The ages of a fruticose lichen of Usnea aurantiacoatra (Jacq.) Bory, from Fildes Peninsula, King George Island, Southwest Antarctic, were determined by radiocarbon (14C), and it is 1993-1996 at bottom and 2006-2007 at top of the lichen branch. The growth rates of U. aurantiacoatra calculated are 4.3 to 5.5 mm year(-1) based on its length and ages. The comparisons show that the growth rates of U. aurantiacoatra are higher than those of U. antarctica (0.4 to 1.1 mm year(-1)). The growth rates of fruticose lichens are always higher, usually >2 mm year(-1), than those of crustose ones, usually lichen growth rates in polar areas may respond to the climatic and environmental changes, and the lichens may act as bio-monitor of natural condition. PMID:24968131

  3. Density but not climate affects the population growth rate of guanacos ( Lama guanicoe) (Artiodactyla, Camelidae)

    Science.gov (United States)

    Zubillaga, María; Skewes, Oscar; Soto, Nicolás; Rabinovich, Jorge E

    2014-01-01

    We analyzed the effects of population density and climatic variables on the rate of population growth in the guanaco ( Lama guanicoe), a wild camelid species in South America. We used a time series of 36 years (1977-2012) of population sampling in Tierra del Fuego, Chile. Individuals were grouped in three age-classes: newborns, juveniles, and adults; for each year a female population transition matrix was constructed, and the population growth rate (λ) was estimated for each year as the matrix highest positive eigenvalue. We applied a regression analysis with finite population growth rate (λ) as dependent variable, and total guanaco population, sheep population, annual mean precipitation, and winter mean temperature as independent variables, with and without time lags. The effect of guanaco population size was statistically significant, but the effects of the sheep population and the climatic variables on guanaco population growth rate were not statistically significant. PMID:25187878

  4. Data compilation of respiration, feeding, and growth rates of marine pelagic organisms

    DEFF Research Database (Denmark)

    2013-01-01

    The metabolic rate of organisms may either be viewed as a basic property from which other vital rates and many ecological patterns emerge and that follows a universal allometric mass scaling law; or it may be considered a property of the organism that emerges as a result of the organism...... similar scaling but different elevations, such that the mass-specific rates converge on a rather narrow size-independent range. In contrast, ingestion and growth rates follow a near-universal taxa-independent ~3/4 mass scaling power law. We argue that the declining mass-specific clearance rates with size......'s adaptation to the environment, with consequently less universal mass scaling properties. Data on body mass, maximum ingestion and clearance rates, respiration rates and maximum growth rates of animals living in the ocean epipelagic were compiled from the literature, mainly from original papers but also from...

  5. RELATIONSHIP AND CAUSALITY BETWEEN ECONOMIC GROWTH RATE AND CERTAIN DISEASES IN THE EUROPEAN UNION

    Directory of Open Access Journals (Sweden)

    MAGHIAR T. Traian

    2009-05-01

    Full Text Available The objective of this paper is to further research the already established relationship between economic growth and health by using the results of some previous works and applying them on the recent data, in order to find out if the economic growth rate i

  6. Regeneration and growth rates of allofragments in four common stream plants

    DEFF Research Database (Denmark)

    Riis, Tenna; Madsen, Tom Vindbæk; Sennels, R. S. H.

    perfoliatus L. and Ranunculus baudotii x pseudofluitans. The objectives of this study were to determine (1) if shoots with an apical tip have higher regeneration (growth of new shoots and rhizomes from allofragments) and colonisation (root attachment in sediment) abilities and higher relative growth rates...

  7. In Search of Inflation Rate Compatible with Growth Target in CEMAC Countries

    OpenAIRE

    Mantsie, Rufin-Willy

    2012-01-01

    Inflation produces adverse effects to growth in economies. However, economic analysis faces aproblem of determining the threshold at which inflation becomes harmful to the economy. Inthis article we try to determine the inflation rate favorable to growth or not for the CEMACcountries and to make contributions to economic policy.

  8. Anthropogenic and biophysical contributions to increasing atmospheric CO2 growth rate and airborne fraction

    Directory of Open Access Journals (Sweden)

    C. Le Quéré

    2008-07-01

    Full Text Available We quantify the relative roles of natural and anthropogenic influences on the growth rate of atmospheric CO2 and the CO2 airborne fraction, considering both interdecadal trends and interannual variability. A combined ENSO-Volcanic Index (EVI relates most (~75% of the interannual variability in CO2 growth rate to the El-Niño-Southern-Oscillation (ENSO climate mode and volcanic activity. Analysis of several CO2 data sets with removal of the EVI-correlated component confirms a previous finding of a detectable increasing trend in CO2 airborne fraction (defined using total anthropogenic emissions including fossil fuels and land use change over the period 1959–2006, at a proportional growth rate 0.24% y−1 with probability ~0.9 of a positive trend. This implies that the atmospheric CO2 growth rate increased slightly faster than total anthropogenic CO2 emissions. An extended form of the Kaya identity relates the increase in the CO2 growth rate (1.9% y−1 over 1959–2006 to the growth rates of four global driving factors: population (contributing +1.7% y−1; per capita income (+1.8% y−1; the total carbon intensity of the global economy (−1.7% y−1; and airborne fraction (averaging +0.2% y−1 with strong interannual variability. Together, the recent (post-2000 increase in growth of per capita income and decline in the negative growth (improvement in the carbon intensity of the economy will drive a significant acceleration in the CO2 growth rate over coming decades, unless these recent trends reverse. To achieve an annual reduction rate in total emissions of −2% y−1 (which would halve emissions in 35 years in the presence of a per-capita income growth rate of 2% y−1 and a population growth rate of 1% y−1, it is necessary to achieve a decline in total carbon intensity of the economy at a rate of around −5% y−1, three times the 1959–2006 average.

  9. Thermal effects on growth and respiration rates of the mayfly, Dolania americana (ephemeroptera)

    International Nuclear Information System (INIS)

    The mayfly Dolania Americana, common in the sand of Upper Three Runs Creek, Savannah River Plant, was studied to determine the effects of seasonal changes in temperature on population growth rates and to determine the effects of slight elevations in water temperature on respiration rates of this benthic species. Growth of the population increased with stream temperature until peak emergence of adults in June and July. There was a strong inverse correlation between body weight and respiration rates of immature nymphs. Respiration rates at 2.5, 5, and 100C above ambient creekwater temperatures were not significantly higher than those measured at ambient creekwater temperatures. (auth)

  10. Phylogenetic, functional, and structural components of variation in bone growth rate of amniotes.

    Science.gov (United States)

    Cubo, Jorge; Legendre, Pierre; de Ricqlès, Armand; Montes, Laëtitia; de Margerie, Emmanuel; Castanet, Jacques; Desdevises, Yves

    2008-01-01

    The biological features observed in every living organism are the outcome of three sets of factors: historical (inherited by homology), functional (biological adaptation), and structural (properties inherent to the materials with which organs are constructed, and the morphogenetic rules by which they grow). Integrating them should bring satisfactory causal explanations of empirical data. However, little progress has been accomplished in practice toward this goal, because a methodologically efficient tool was lacking. Here we use a new statistical method of variation partitioning to analyze bone growth in amniotes. (1) Historical component. The variation of bone growth rates contains a significant phylogenetic signal, suggesting that the observed patterns are partly the outcome of shared ancestry. (2) Functional causation. High growth rates, although energy costly, may be adaptive (i.e., they may increase survival rates) in taxa showing short growth periods (e.g., birds). In ectothermic amniotes, low resting metabolic rates may limit the maximum possible growth rates. (3) Structural constraint. Whereas soft tissues grow through a multiplicative process, growth of mineralized tissues is accretionary (additive, i.e., mineralization fronts occur only at free surfaces). Bone growth of many amniotes partially circumvents this constraint: it is achieved not only at the external surface of the bone shaft, but also within cavities included in the bone cortex as it grows centrifugally. Our approach contributes to the unification of historicism, functionalism, and structuralism toward a more integrated evolutionary biology. PMID:18315815

  11. Specific growth rate regulation in a simulated fed-batch E. coli fermentation

    OpenAIRE

    Rocha, I.; Ferreira, E. C.

    2006-01-01

    The specific growth rate is one of the most important process variables characterizing the state of microorganisms during fermentations mainly because the biosynthesis of many products of interest is often related with the values assumed by this parameter. In the particular case of the fed-batch operation of Escherichia coli for the production of recombinant proteins, it is often argued that both pre- and the post-induction specific growth rates should be closely controlled in ...

  12. ENDOSULFAN INDUCED CHANGES IN GROWTH RATE, PIGMENT COMPOSITION AND PHOTOSYNTHETIC ACTIVITY OF MOSQUITO FERN AZOLLA MICROPHYLLA

    OpenAIRE

    Raja W.; Rathaur P.; John S. A.; Ramteke P. W.

    2012-01-01

    This paper is the first in a series reporting a study on the effects of different concentrations of insecticide, Endosulfan (0-600ppm) was premeditated on 5th day after insecticide exposure with respect to growth rate, pigment composition and photosynthetic activity of Azolla microphylla under laboratory conditions which become non-target organism in the rice fields. Endosulfan inhibited the relative growth rate, pigment content and photosynthetic O2 evolution. Phycocyanin was main target fo...

  13. Adhesion and growth rate of Clostridium cellulolyticum ATCC 35319 on crystalline cellulose.

    OpenAIRE

    Gelhaye, E.; Petitdemange, H.; Gay, R

    1993-01-01

    The rate of tritiated-thymidine incorporation into DNA was used to estimate Clostridium cellulolyticum H10 growth rates on Avicel cellulose, taking into consideration both the unattached cells and the cells adhered to the substrate. The generation time on cellobiose calculated from the data on cell density (4.5 h) agreed well with the generation time calculated by tritiated-thymidine incorporation (3.8 h). Growth on Avicel cellulose occurred when bacteria were adhered to their substrate; 80% ...

  14. Curved characteristics best suited for Growth rates, Relative strength and Performance Time of female Olympic weightlifters

    OpenAIRE

    EBADA, Khaled

    2014-01-01

    This study aims to identify Growth rates, Relative strength, and performance time for female lifters and defining Curved characteristics best suited for growth rates, relative strength, and performance Time of female Olympic weightlifters and evaluate the performance of snatch and Clean & Jerk for female lifters, coaches use the curved characteristics as standard guide them through planning and preparing training programs. The study Applied on a sample of 88 female lifter participants in weig...

  15. Anti-Candida albicans activity of Pichia anomala as determined by a growth rate reduction assay.

    OpenAIRE

    Sawant, A D; Abdelal, A T; Ahearn, D G

    1988-01-01

    Killer toxin activity of Pichia anomala WC65 appeared fungicidal for P. bimundalis WC38 and fungistatic for Candida albicans RC1. Inhibitory activity against sensitive C. albicans showed a linear relationship between toxin concentrations and the inverse of the reduced growth rates. The plot of toxin concentrations against growth rates was hyperbolic, as is characteristic of saturation kinetics. Sensitivity of C. albicans to the toxin decreased with increased cell age. The measurement of growt...

  16. Density but not climate affects the population growth rate of guanacos ( Lama guanicoe) (Artiodactyla, Camelidae)

    OpenAIRE

    María Zubillaga; Oscar Skewes; Nicolás Soto; Jorge E Rabinovich

    2014-01-01

    We analyzed the effects of population density and climatic variables on the rate of population growth in the guanaco ( Lama guanicoe), a wild camelid species in South America. We used a time series of 36 years (1977-2012) of population sampling in Tierra del Fuego, Chile. Individuals were grouped in three age-classes: newborns, juveniles, and adults; for each year a female population transition matrix was constructed, and the population growth rate (λ) was estimated for each year as the matri...

  17. Oil Export Earnings, Exchange Rate Variability, and Economic Growth in Nigeria

    OpenAIRE

    Folorunso Sunday Ayadi; Olubunmi Elizabeth Oluwagbemi

    2014-01-01

    This paper investigates oil revenue and exchange rate volatility and as well as their impacts on Nigerian economic growth which is examined from 1980 – 2010. Exchange rate volatility was captured using standard deviationof monthly nominal effective exchange rate. During this period, Nigeria recorded high levels of volatility (in oil receipt and effective exchange rate) as can be seen from the Autoregressive Conditional Heteroskedasticity (ARCH) and the General Autoregressive Conditional Het...

  18. Effects of the breed, sex and age on cellular content and growth factor release from equine pure-platelet rich plasma and pure-platelet rich gel

    OpenAIRE

    Giraldo Carlos E; López Catalina; Álvarez María E; Samudio Ismael J; Prades Marta; Carmona Jorge U

    2013-01-01

    Abstract Background There is no information on the effects of the breed, gender and age on the cellular content and growth factor (GF) release from equine pure-platelet rich plasma (P-PRP) and pure-platelet rich gel (P-PRG). The objectives of this study were: 1) to compare the cellular composition of P-PRP with whole blood and platelet poor plasma (PPP); 2) to compare the concentration of transforming GF beta 1 (TGF-β1) and platelet derived GF isoform BB (PDGF-BB) between P-PRP treated with n...

  19. SCC crack growth rate of cold worked 316L stainless steel in PWR environment

    Energy Technology Data Exchange (ETDEWEB)

    Du, Donghai; Chen, Kai; Yu, Lun; Lu, Hui [School of Nuclear Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Zhang, Lefu, E-mail: lfzhang@sjtu.edu.cn [School of Nuclear Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Shi, Xiuqiang; Xu, Xuelian [Shanghai Nuclear Engineering Research and Design Institute, Shanghai 200233 (China)

    2015-01-15

    Many component failures in nuclear power plants were found to be caused by stress corrosion cracking (SCC) of cold worked austenitic steels. Some of the pressure boundary component materials are even cold worked up to 35% plastic deformation, leaving high residual stress and inducing high growth rate of corrosion crack. Controlling water chemistry is one of the best counter measure to mitigate this problem. In this work, the effects of temperature (200 up to 325 °C) and dissolved oxygen (0 up to 2000 μg/L) on SCC crack growth rates of cold worked austenitic stainless steel type 316L have been tested by using direct current potential drop (DCPD) method. The results showed that temperature affected SCC crack growth rates more significantly in oxygenated water than in deaerated water. In argon deaerated water, the crack growth rate exhibited a peak at about 250 °C, which needs further verification. At 325 °C, the SCC crack growth rate increased rapidly with the increase of dissolved oxygen concentration within the range from 0 up to 200 μg/L, while when dissolved oxygen was above 200 μg/L, the crack growth rate followed a shallower dependence on dissolved oxygen concentration.

  20. On the measurement of fatigue crack growth rates of steels using non-standard specimens

    International Nuclear Information System (INIS)

    Fatigue crack growth rates were measured using K-Decreasing Method during precracking of standard (Compact Tension) and non-standard (Charpy V -notch and Three-Point-Bend) specimens of four ferritic steels. Crack growth rates from the specimens were then inter-compared. The results from Compact Tension specimens were within ±15% error bar of the results from Three-Point-Bend specimens and were within ±6% error bar of the results from Charpy V -notch. The inter-comparison of the mean crack growth rates of any of the steels as obtained using different specimen geometries did not reveal any systematic dependence of crack growth rates vis-a-vis the specimens utilized. The experimental results suggested the possibility of generating material crack growth rate data as a bonus during fatigue precracking of fracture toughness specimens including Charpy V-notch and Three-Point-Bend specimens. The results also indicated distinct possibility of the measurement of steady state fatigue crack growth rate of irradiated steels using either Compact Tension and Three-Point-Bend fracture toughness specimens with a/W ≤ 0.65 or during precrackingstep of a few designated impact specimens from surveillance locations to be used as fracture toughness specimens for generation of irradiated material fracture toughness data. (author)

  1. Factors influencing crystal growth rates from undercooled liquids of pharmaceutical compounds.

    Science.gov (United States)

    Trasi, Niraj S; Baird, Jared A; Kestur, Umesh S; Taylor, Lynne S

    2014-08-21

    Amorphous forms of drugs are increasingly being used to deliver poorly water-soluble compounds. Therefore, understanding the magnitude and origin of differences in crystallization kinetics is highly important. The goal of this study was to better understand the factors that influence crystal growth rates from pharmaceutically relevant undercooled liquids and to evaluate the range of growth rates observed. The crystal growth rates of 31 drugs were determined using an optical microscope in the temperature region between the glass transition temperature (Tg) and the melting temperature (Tm). Thermodynamic parameters such as Tm, melting enthalpy, and Tg were determined using a differential scanning calorimeter (DSC). Selected viscosity values for the undercooled liquid were taken from the literature. The growth rates of the different compounds were found to be very different from each other with a variation of about 5 orders of magnitude between the fastest growing compounds and the slowest growing compounds. A comparison of the physicochemical properties showed that compounds that had fast crystal growth rates had smaller molecular weights, higher melting temperatures, lower melt entropies, lower melt viscosities, and higher crystal densities. Variations in the growth rates of the compounds could be rationalized to a large extent by considering the thermodynamic driving force for crystallization, the viscosity, and the entropy difference between the melt and undercooled liquid. This study therefore provides important insight into factors that may compromise the stability of amorphous pharmaceuticals. PMID:25076138

  2. SCC crack growth rate of cold worked 316L stainless steel in PWR environment

    International Nuclear Information System (INIS)

    Many component failures in nuclear power plants were found to be caused by stress corrosion cracking (SCC) of cold worked austenitic steels. Some of the pressure boundary component materials are even cold worked up to 35% plastic deformation, leaving high residual stress and inducing high growth rate of corrosion crack. Controlling water chemistry is one of the best counter measure to mitigate this problem. In this work, the effects of temperature (200 up to 325 °C) and dissolved oxygen (0 up to 2000 μg/L) on SCC crack growth rates of cold worked austenitic stainless steel type 316L have been tested by using direct current potential drop (DCPD) method. The results showed that temperature affected SCC crack growth rates more significantly in oxygenated water than in deaerated water. In argon deaerated water, the crack growth rate exhibited a peak at about 250 °C, which needs further verification. At 325 °C, the SCC crack growth rate increased rapidly with the increase of dissolved oxygen concentration within the range from 0 up to 200 μg/L, while when dissolved oxygen was above 200 μg/L, the crack growth rate followed a shallower dependence on dissolved oxygen concentration

  3. Crack growth rate under cyclic bending in the explosively welded steel/titanium bimetals

    International Nuclear Information System (INIS)

    Highlights: ► The results of the tests on fatigue crack growth in a steel/titanium composite under oscillatory bending. ► Hardness of both joined materials in all their section is higher than hardness of the materials before cladding. ► The main crack propagated in the direction parallel to the loading action and they did not include secondary cracks. ► When the crack growth was being passed along the interface line, decrease of the crack growth rate took place. -- Abstract: The paper presents the results of the tests on fatigue crack growth in a steel/titanium composite under oscillatory bending. Two kinds of specimens of rectangular cross sections were tested. In the tested specimens, the ratio of heights of basic and overlaid materials was h1:h2 = 2.5:1 and 1:1. In the specimens, the fatigue crack growth was parallel to the applied loading and its direction changed at the interface line. Next, the crack growth along the interface line or the crack growth passing through the interface line were observed. When the crack growth passed along the interface line, decrease of the crack growth rate took place. The specimens have the uniform crack growth at both sides of lateral surfaces. At the composite fractures in the steel and titanium, transcrystalline cracks are dominating.

  4. An inverse modeling procedure to determine particle growth and nucleation rates from measured aerosol size distributions

    Directory of Open Access Journals (Sweden)

    B. Verheggen

    2006-01-01

    Full Text Available Classical nucleation theory is unable to explain the ubiquity of nucleation events observed in the atmosphere. This shows a need for an empirical determination of the nucleation rate. Here we present a novel inverse modeling procedure to determine particle nucleation and growth rates based on consecutive measurements of the aerosol size distribution. The particle growth rate is determined by regression analysis of the measured change in the aerosol size distribution over time, taking into account the effects of processes such as coagulation, deposition and/or dilution. This allows the growth rate to be determined with a higher time-resolution than can be deduced from inspecting contour plots ('banana-plots''. Knowing the growth rate as a function of time enables the evaluation of the time of nucleation of measured particles of a certain size. The nucleation rate is then obtained by integrating the particle losses from time of measurement to time of nucleation. The regression analysis can also be used to determine or verify the optimum value of other parameters of interest, such as the wall loss or coagulation rate constants. As an example, the method is applied to smog chamber measurements. This program offers a powerful interpretive tool to study empirical aerosol population dynamics in general, and nucleation and growth in particular.

  5. Stature of Sub-arctic Birch in Relation to Growth Rate, Lifespan and Tree Form

    OpenAIRE

    JÓNSSON, THORBERGUR HJALTI

    2004-01-01

    • Background and Aims Sub-arctic mountain birch Betula pubescens var. pumila communities in the North Atlantic region are of variable stature, ranging from prostrate scrubs to forests with trees up to 12 m high. Four hypotheses were tested, relating growth and population characteristics of sub-arctic birch woodland and scrub to tree stature; i.e. the variable stature of birch woods is due to differences in (1) the mean growth rate; (2) the age-related patterns of growth rate; (3) the life exp...

  6. Mps1 (Monopolar Spindle 1) Protein Inhibition Affects Cellular Growth and Pro-Embryogenic Masses Morphology in Embryogenic Cultures of Araucaria angustifolia (Araucariaceae)

    Science.gov (United States)

    Douétts-Peres, Jackellinne C.; Cruz, Marco Antônio L.; Reis, Ricardo S.; Heringer, Angelo S.; de Oliveira, Eduardo A. G.; Elbl, Paula M.; Floh, Eny I. S.; Silveira, Vanildo

    2016-01-01

    Somatic embryogenesis has been shown to be an efficient tool for studying processes based on cell growth and development. The fine regulation of the cell cycle is essential for proper embryo formation during the process of somatic embryogenesis. The aims of the present work were to identify and perform a structural and functional characterization of Mps1 and to analyze the effects of the inhibition of this protein on cellular growth and pro-embryogenic mass (PEM) morphology in embryogenic cultures of A. angustifolia. A single-copy Mps1 gene named AaMps1 was retrieved from the A. angustifolia transcriptome database, and through a mass spectrometry approach, AaMps1 was identified and quantified in embryogenic cultures. The Mps1 inhibitor SP600125 (10 μM) inhibited cellular growth and changed PEMs, and these effects were accompanied by a reduction in AaMps1 protein levels in embryogenic cultures. Our work has identified the Mps1 protein in a gymnosperm species for the first time, and we have shown that inhibiting Mps1 affects cellular growth and PEM differentiation during A. angustifolia somatic embryogenesis. These data will be useful for better understanding cell cycle control during somatic embryogenesis in plants. PMID:27064899

  7. Experimental design and estimation of growth rate distributions in size-structured shrimp populations

    International Nuclear Information System (INIS)

    We discuss inverse problem results for problems involving the estimation of probability distributions using aggregate data for growth in populations. We begin with a mathematical model describing variability in the early growth process of size-structured shrimp populations and discuss a computational methodology for the design of experiments to validate the model and estimate the growth-rate distributions in shrimp populations. Parameter-estimation findings using experimental data from experiments so designed for shrimp populations cultivated at Advanced BioNutrition Corporation are presented, illustrating the usefulness of mathematical and statistical modeling in understanding the uncertainty in the growth dynamics of such populations

  8. Effects of soil nitrogen:phosphorus ratio on growth rate of Artemisia ordosica seedlings

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    To address how the ratios of nitrogen and phosphorus (N:P ratios) in soil affect plant growth, we performed a two-factor (soil available N:P ratios and plant density) randomized block pot experiment to examine the relationships between soil N:P ratios, and the N:P ratios and growth rate of Artemisia ordosica seedlings. Under moderate water stress and adequate nutrient status, both soil N:P and plant density influenced the N:P ratios and growth rates of A. ordosica. With the increase of soil N:P ratios, the growth rates of A. ordosica seedlings decreased significantly. With the increase of soil N:P ratios, N:P ratios in A. ordosica seedlings increased significantly. While the nitrogen concentrations in the plant increased slightly, the phosphorus concentrations significantly decreased. With the increase of plant density, the shoot N:P ratios and growth rates significantly decreased, which resulted from soil N:P ratios. Thus, soil N:P ratios influenced the N:P ratios in A. ordosica seedlings, and hence, influenced its growth. Our results suggest that, under adequate nutrient environment, soil N:P ratios can be a limiting factor for plant growth.

  9. In situ growth rates and biofilm development of Pseudomonas aeruginosa populations in chronic lung infections

    DEFF Research Database (Denmark)

    Yang, L.; Haagensen, J.A.; Jelsbak, L.; Sternberg, C.; Høiby, Niels; Molin, S.; Johansen, Helle Krogh

    2008-01-01

    The growth dynamics of bacterial pathogens within infected hosts are a fundamental but poorly understood feature of most infections. We have focused on the in situ distribution and growth characteristics of two prevailing and transmissible Pseudomonas aeruginosa clones that have caused chronic lung...... matrix, whereas nonmucoid variants were present mainly as dispersed cells. To obtain estimates of the growth rates of P. aeruginosa in CF lungs, we used quantitative FISH to indirectly measure growth rates of bacteria in sputum samples (reflecting the in vivo lung conditions). The concentration of r......-phase subpopulation seemed to be present in sputa. This was found for both mucoid and nonmucoid variants despite their different organizations in sputum. The results suggest that the bacterial population may be confronted with selection forces that favor optimized growth activities. This scenario constitutes a new...

  10. Growth rate of late passage sarcoma cells is independent of epigenetic events but dependent on the amount of chromosomal aberrations

    International Nuclear Information System (INIS)

    Soft tissue sarcomas (STS) are characterized by co-participation of several epigenetic and genetic events during tumorigenesis. Having bypassed cellular senescence barriers during oncogenic transformation, the factors further affecting growth rate of STS cells remain poorly understood. Therefore, we investigated the role of gene silencing (DNA promoter methylation of LINE-1, PTEN), genetic aberrations (karyotype, KRAS and BRAF mutations) as well as their contribution to the proliferation rate and migratory potential that underlies “initial” and “final” passage sarcoma cells. Three different cell lines were used, SW982 (synovial sarcoma), U2197 (malignant fibrous histiocytoma (MFH)) and HT1080 (fibrosarcoma). Increased proliferative potential of final passage STS cells was not associated with significant differences in methylation (LINE-1, PTEN) and mutation status (KRAS, BRAF), but it was dependent on the amount of chromosomal aberrations. Collectively, our data demonstrate that these fairly differentiated/advanced cancer cell lines have still the potential to gain an additional spontaneous growth benefit without external influences and that maintenance of increased proliferative potential towards longevity of STS cells (having crossed senescence barriers) may be independent of overt epigenetic alterations. -- Highlights: Increased proliferative potential of late passage STS cells was: • Not associated with epigenetic changes (methylation changes at LINE-1, PTEN). • Not associated with mutation status of KRAS, BRAF. • Dependent on presence/absence of chromosomal aberrations

  11. Growth rate of late passage sarcoma cells is independent of epigenetic events but dependent on the amount of chromosomal aberrations

    Energy Technology Data Exchange (ETDEWEB)

    Becerikli, Mustafa; Jacobsen, Frank; Rittig, Andrea; Köhne, Wiebke [Department of Plastic Surgery, BG University Hospital Bergmannsheil, Ruhr-University Bochum (Germany); Nambiar, Sandeep; Mirmohammadsadegh, Alireza; Stricker, Ingo; Tannapfel, Andrea [Institute of Pathology, Ruhr-University Bochum (Germany); Wieczorek, Stefan; Epplen, Joerg Thomas [Department of Human Genetics, Ruhr-University Bochum (Germany); Tilkorn, Daniel [Department of Plastic Surgery, BG University Hospital Bergmannsheil, Ruhr-University Bochum (Germany); Steinstraesser, Lars, E-mail: lars.steinstraesser@rub.de [Department of Plastic Surgery, BG University Hospital Bergmannsheil, Ruhr-University Bochum (Germany)

    2013-07-15

    Soft tissue sarcomas (STS) are characterized by co-participation of several epigenetic and genetic events during tumorigenesis. Having bypassed cellular senescence barriers during oncogenic transformation, the factors further affecting growth rate of STS cells remain poorly understood. Therefore, we investigated the role of gene silencing (DNA promoter methylation of LINE-1, PTEN), genetic aberrations (karyotype, KRAS and BRAF mutations) as well as their contribution to the proliferation rate and migratory potential that underlies “initial” and “final” passage sarcoma cells. Three different cell lines were used, SW982 (synovial sarcoma), U2197 (malignant fibrous histiocytoma (MFH)) and HT1080 (fibrosarcoma). Increased proliferative potential of final passage STS cells was not associated with significant differences in methylation (LINE-1, PTEN) and mutation status (KRAS, BRAF), but it was dependent on the amount of chromosomal aberrations. Collectively, our data demonstrate that these fairly differentiated/advanced cancer cell lines have still the potential to gain an additional spontaneous growth benefit without external influences and that maintenance of increased proliferative potential towards longevity of STS cells (having crossed senescence barriers) may be independent of overt epigenetic alterations. -- Highlights: Increased proliferative potential of late passage STS cells was: • Not associated with epigenetic changes (methylation changes at LINE-1, PTEN). • Not associated with mutation status of KRAS, BRAF. • Dependent on presence/absence of chromosomal aberrations.

  12. Effects of chloroquine and hepatic stimulator substance on cellular accumulation and nuclear binding of 125I-epidermal growth factor in primary culture of adult rat hepatocytes

    International Nuclear Information System (INIS)

    The effects of chloroquine and hepatic stimulator substance (HSS) on cellular accumulation and nuclear binding of 125I-epidermal growth factor (EGF) were examined in primary culture of adult rat hepatocytes. When intact hepatocytes were incubated at 37 degrees C with 125I-EGF, the cellular accumulation and the nuclear binding reached a peak at 1 h and declined thereafter, where the nuclear binding was 2.49% at 1 h and 2.53% at 2 h. Chloroquine resulted in a time-dependent increase in the cellular accumulation and the nuclear binding was 3.37% at 1 h and 3.72% at 2 h. In contrast, HSS produced no change in each value, suggesting that HSS does not modulate EGF receptors in plasma membrane and nucleus

  13. Jackknife-corrected parametric bootstrap estimates of growth rates in bivalve mollusks using nearest living relatives.

    Science.gov (United States)

    Dexter, Troy A; Kowalewski, Michał

    2013-12-01

    Quantitative estimates of growth rates can augment ecological and paleontological applications of body-size data. However, in contrast to body-size estimates, assessing growth rates is often time-consuming, expensive, or unattainable. Here we use an indirect approach, a jackknife-corrected parametric bootstrap, for efficient approximation of growth rates using nearest living relatives with known age-size relationships. The estimate is developed by (1) collecting a sample of published growth rates of closely related species, (2) calculating the average growth curve using those published age-size relationships, (3) resampling iteratively these empirically known growth curves to estimate the standard errors and confidence bands around the average growth curve, and (4) applying the resulting estimate of uncertainty to bracket age-size relationships of the species of interest. This approach was applied to three monophyletic families (Donacidae, Mactridae, and Semelidae) of mollusk bivalves, a group characterized by indeterministic shell growth, but widely used in ecological, paleontological, and geochemical research. The resulting indirect estimates were tested against two previously published geochemical studies and, in both cases, yielded highly congruent age estimates. In addition, a case study in applied fisheries was used to illustrate the potential of the proposed approach for augmenting aquaculture management practices. The resulting estimates of growth rates place body size data in a constrained temporal context and confidence intervals associated with resampling estimates allow for assessing the statistical uncertainty around derived temporal ranges. The indirect approach should allow for improved evaluation of diverse research questions, from sustainability of industrial shellfish harvesting to climatic interpretations of stable isotope proxies extracted from fossil skeletons. PMID:24071629

  14. How to determine control of growth rate in a chemostat. Using metabolic control analysis to resolve the paradox

    DEFF Research Database (Denmark)

    Snoep, Jacky L.; Jensen, Peter Ruhdal; Groeneveld, Philip;

    1994-01-01

    how, paradoxically, one can determine control of growth rate, of growth yield and of other fluxes in a chemostat. We develop metabolic control analysis for the chemostat. this analysis does not depend on the particular way in which specific growth rate varies with the concentration of the growth...

  15. Capital accumulation, structural change and real exchange rate in a Keynesian-Structuralist growth model

    Directory of Open Access Journals (Sweden)

    Oreiro José Luis

    2015-01-01

    Full Text Available The aim of this paper is to show at theoretical level that maintaining a competitive real exchange rate positively affects the economic growth of developing countries by means of a Keynesian-Structuralist model that combines elements of Kaleckian growth models with the balance of payments constrained growth models pioneered developed by Thirlwall. In this setting, the level of real exchange rate is capable, due to its effect over capital accumulation, to induce a structural change in the economy, making endogenous income elasticities of exports and imports. For reasonable parameter values it is shown that in steady-state growth there is two long-run equilibrium values for real exchange rate, one that corresponds to an under-valued currency and another that corresponds to an over-valued currency. If monetary authorities run exchange rate policy in order to target a competitive level for real exchange rate, than under-valued equilibrium is stable and the economy will show a high growth rate in the long-run.

  16. Element content of Ochromonas danica: a replicated chemostat study controlling the growth rate and temperature.

    Science.gov (United States)

    Simonds, Savannah; Grover, James P; Chrzanowski, Thomas H

    2010-11-01

    Ecological stoichiometry focuses on the balance between multiple nutrient elements in resources and in consumers of those resources. The major consumers of bacteria in aquatic food webs are heterotrophic and mixotrophic nanoflagellates. Despite the importance of this consumer-resource interaction to understanding nutrient dynamics in the aquatic food web, few data are available addressing the element stoichiometry of flagellate consumers. Ochromonas danica, a mixotrophic bacterivore, was used as a model organism to study the relationships among temperature, growth rate and element stoichiometry. Ochromonas danica was grown in chemostats at dilution rates ranging between 0.03 and 0.10 h(-1) and temperatures ranging between 15 and 28 °C. Cells accumulated elements as interactive functions of temperature and growth rate, with the highest element concentrations corresponding to cells grown at a low temperature and high growth rates. The highest concentrations of elements were associated with small cells. Temperature and growth rate affected the element stoichiometry (as C:N, C:P and N:P) of O. danica in a complex manner, but the growth rate had a greater effect on ratios than did temperature. PMID:21039649

  17. Systems Level Regulation of Rhythmic Growth Rate and Biomass Accumulation in Grasses

    Energy Technology Data Exchange (ETDEWEB)

    Kay, Steve A. [University of California San Diego

    2013-05-02

    Several breakthroughs have been recently made in our understanding of plant growth and biomass accumulation. It was found that plant growth is rhythmically controlled throughout the day by the circadian clock through a complex interplay of light and phytohormone signaling pathways. While plants such as the C4 energy crop sorghum (Sorghum bicolor (L.) Moench) and possibly the C3 grass (Brachypodium distachyon) also exhibit daily rhythms in growth rate, the molecular details of its regulation remain to be explored. A better understanding of diurnally regulated growth behavior in grasses may lead to species-specific mechanisms highly relevant to future strategies to optimize energy crop biomass yield. Here we propose to devise a systems approach to identify, in parallel, regulatory hubs associated with rhythmic growth in C3 and C4 plants. We propose to use rhythmicity in daily growth patterns to drive the discovery of regulatory network modules controlling biomass accumulation.

  18. Effect of Temperature on the Void Growth in Pure Aluminium at High Strain-Rate Loading

    Institute of Scientific and Technical Information of China (English)

    QI Mei-Lan; HE Hong-Liang; YAN Shi-Lin

    2007-01-01

    @@ With the environment temperature varying from 273K to 773K, the dynamic process of void growth in pure aluminium at high strain-rate loading is calculated based on the dynamic growth equation of a void with internal pressure. The result shows that the effect of temperature on the growth of void should be emphasized. Because the initial pressure of void with gas will increase and the viscosity of materials will decrease with the rising of temperature, the growth of void is accelerated. Furthermore, material inertia restrains the growth of void evidently when the diameter exceeds 10μm. The effect of surface tension is very weak in the whole process of void growth.

  19. Value of volume measurements in evaluating abdominal aortic aneurysms growth rate and need for surgical treatment

    Energy Technology Data Exchange (ETDEWEB)

    Kontopodis, Nikolaos, E-mail: kontopodisn@yahoo.gr [Department of Vascular Surgery, University of Crete Medical School, Heraklion (Greece); Metaxa, Eleni, E-mail: emmetaxa@gmail.com [Institute of Applied and Computational Mathematics, Foundation for Research and Technology-Hellas, Heraklion, Crete (Greece); Papaharilaou, Yannis, E-mail: yannisp@iacm.forth.gr [Institute of Applied and Computational Mathematics, Foundation for Research and Technology-Hellas, Heraklion, Crete (Greece); Georgakarakos, Efstratios, E-mail: efstratiosgeorg@gmail.com [Vascular Surgery Department, “Demokritus” University of Thrace Medical School, Alexandroupolis (Greece); Tsetis, Dimitris, E-mail: tsetis@med.uoc.gr [Interventional Radiology Unit, Department of Radiology, University of Crete Medical School, Heraklion, Crete (Greece); Ioannou, Christos V., E-mail: ioannou@med.uoc.gr [Department of Vascular Surgery, University of Crete Medical School, Heraklion (Greece)

    2014-07-15

    Purpose: To examine whether indices other than the traditionally used abdominal aortic aneurysm (AAA) maximum diameter, such as AAA volume, intraluminal thrombus (ILT) thickness and ILT volume, may be superior to evaluate aneurismal enlargement. Materials and methods: Thirty-four small AAAs (initially presenting a maximum diameter <5.5 cm which is the threshold for surgical repair) with an initial and a follow-up CT were examined. Median increase and percentile annual change of these variables was calculated. Correlation between growth rates as determined by the new indices under evaluation and those of maximum diameter were assessed. AAAs were divided according to outcome (surveillance vs. elective repair after follow-up which is based on the maximum diameter criterion) and according to growth rate (high vs. low) based on four indices. Contingency between groups of high/low growth rate regarding each of the four indices on one hand and those regarding need for surgical repair on the other was assessed. Results: A strong correlation between growth rates of maximum diameter and those of AAA and ILT volumes could be established. Evaluation of contingency between groups of outcome and those of growth rate revealed significant associations only for AAA and ILT volumes. Subsequently AAAs with a rapid volumetric increase over time had a likelihood ratio of 10 to be operated compared to those with a slower enlargement. Regarding increase of maximum diameter, likelihood ratio between AAAs with rapid and those with slow expansion was only 3. Conclusion: Growth rate of aneurysms regarding 3Dimensional indices of AAA and ILT volumes is significantly associated with the need for surgical intervention while the same does not hold for growth rates determined by 2Dimensional indices of maximum diameter and ILT thickness.

  20. Value of volume measurements in evaluating abdominal aortic aneurysms growth rate and need for surgical treatment

    International Nuclear Information System (INIS)

    Purpose: To examine whether indices other than the traditionally used abdominal aortic aneurysm (AAA) maximum diameter, such as AAA volume, intraluminal thrombus (ILT) thickness and ILT volume, may be superior to evaluate aneurismal enlargement. Materials and methods: Thirty-four small AAAs (initially presenting a maximum diameter <5.5 cm which is the threshold for surgical repair) with an initial and a follow-up CT were examined. Median increase and percentile annual change of these variables was calculated. Correlation between growth rates as determined by the new indices under evaluation and those of maximum diameter were assessed. AAAs were divided according to outcome (surveillance vs. elective repair after follow-up which is based on the maximum diameter criterion) and according to growth rate (high vs. low) based on four indices. Contingency between groups of high/low growth rate regarding each of the four indices on one hand and those regarding need for surgical repair on the other was assessed. Results: A strong correlation between growth rates of maximum diameter and those of AAA and ILT volumes could be established. Evaluation of contingency between groups of outcome and those of growth rate revealed significant associations only for AAA and ILT volumes. Subsequently AAAs with a rapid volumetric increase over time had a likelihood ratio of 10 to be operated compared to those with a slower enlargement. Regarding increase of maximum diameter, likelihood ratio between AAAs with rapid and those with slow expansion was only 3. Conclusion: Growth rate of aneurysms regarding 3Dimensional indices of AAA and ILT volumes is significantly associated with the need for surgical intervention while the same does not hold for growth rates determined by 2Dimensional indices of maximum diameter and ILT thickness

  1. Small regulatory RNA-induced growth rate heterogeneity of Bacillus subtilis.

    OpenAIRE

    Mars, Ruben A. T.; Pierre Nicolas; Mariano Ciccolini; Ewoud Reilman; Alexander Reder; Marc Schaffer; Ulrike Mäder; Uwe Völker; Jan Maarten van Dijl; Denham, Emma L.

    2015-01-01

    Isogenic bacterial populations can consist of cells displaying heterogeneous physiological traits. Small regulatory RNAs (sRNAs) could affect this heterogeneity since they act by fine-tuning mRNA or protein levels to coordinate the appropriate cellular behavior. Here we show that the sRNA RnaC/S1022 from the Gram-positive bacterium Bacillus subtilis can suppress exponential growth by modulation of the transcriptional regulator AbrB. Specifically, the post-transcriptional abrB-RnaC/S1022 inter...

  2. Characteristics of Growth Rate of Coral Porites from Sanya Bay, Hainan Island and its Relationship to Environmental Variables

    Institute of Scientific and Technical Information of China (English)

    Shi Qi; Zhang Yechun; Sun Donghuai

    2003-01-01

    The time series of annual and seasonal growth rate of two coral Porites, collected at different sites of fringe reef in the Sanya Bay, Hainan Island have been obtained by analyzing X-radiograph of skeletal band. There are obvious seasonal variations of the growth rate in two corals, the average low rate in winter and the average high rate from spring to autumn. Compared with the time series of environmental variables, the coral growth rate is only correlated statistically with seawater temperature and not related to rainfall and sunshine. Furthermore, the growth rate in spring and summer is correlated directly with seawater temperature of the winter-early spring ( between December and March ) and the other seasonal growth rate has no relationship with seasonal variations of seawater temperature. We propose that seawater temperature is one of the factors affecting the coral growth rate in the area and the low seawater temperature is a primary control of the seasonal growth rate.

  3. Generation time, net reproductive rate, and growth in stage-age-structured populations

    DEFF Research Database (Denmark)

    Steiner, Uli; Tuljapurkar, Shripad; Coulson, Tim

    2014-01-01

    Abstract Major insights into the relationship between life-history features and fitness have come from Lotka's proof that population growth rate is determined by the level (expected amount) of reproduction and the average timing of reproduction of an individual. But this classical result is limited...... to age-structured populations. Here we generalize this result to populations structured by stage and age by providing a new, unique measure of reproductive timing (Tc) that, along with net reproductive rate (R0), has a direct mathematical relationship to and approximates growth rate (r). We use...... macroscopic features of the life history determine population growth rate r and reveal a complex interplay of trait dynamics, timing, and level of reproduction. Our results contribute to a new framework of population and evolutionary dynamics in stage-and-age-structured populations....

  4. Pretreatment Growth Rate Predicts Radiation Response in Vestibular Schwannomas

    Energy Technology Data Exchange (ETDEWEB)

    Niu, Nina N. [Department of Radiation Oncology, Harvard Medical School, Massachusetts General Hospital, Boston, Massachusetts (United States); Harvard Medical School, Department of Medicine, Brigham and Women' s Hospital, Boston, Massachusetts (United States); Niemierko, Andrzej [Department of Radiation Oncology, Harvard Medical School, Massachusetts General Hospital, Boston, Massachusetts (United States); Larvie, Mykol [Harvard Medical School, Department of Radiology, Massachusetts General Hospital, Boston, Massachusetts (United States); Curtin, Hugh [Harvard Medical School, Department of Radiology, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts (United States); Loeffler, Jay S. [Department of Radiation Oncology, Harvard Medical School, Massachusetts General Hospital, Boston, Massachusetts (United States); McKenna, Michael J. [Harvard Medical School, Department of Otolaryngology, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts (United States); Shih, Helen A., E-mail: hshih@partners.org [Department of Radiation Oncology, Harvard Medical School, Massachusetts General Hospital, Boston, Massachusetts (United States)

    2014-05-01

    Purpose: Vestibular schwannomas (VS) are often followed without initial therapeutic intervention because many tumors do not grow and radiation therapy is associated with potential adverse effects. In an effort to determine whether maximizing initial surveillance predicts for later treatment response, the predictive value of preirradiation growth rate of VS on response to radiation therapy was assessed. Methods and Materials: Sixty-four patients with 65 VS were treated with single-fraction stereotactic radiation surgery or fractionated stereotactic radiation therapy. Pre- and postirradiation linear expansion rates were estimated using volumetric measurements on sequential magnetic resonance images (MRIs). In addition, postirradiation tumor volume change was classified as demonstrating shrinkage (ratio of volume on last follow-up MRI to MRI immediately preceding irradiation <80%), stability (ratio 80%-120%), or expansion (ratio >120%). The median pre- and postirradiation follow-up was 20.0 and 27.5 months, respectively. Seven tumors from neurofibromatosis type 2 (NF2) patients were excluded from statistical analyses. Results: In the 58 non-NF2 patients, there was a trend of correlation between pre- and postirradiation volume change rates (slope on linear regression, 0.29; P=.06). Tumors demonstrating postirradiation expansion had a median preirradiation growth rate of 89%/year, and those without postirradiation expansion had a median preirradiation growth rate of 41%/year (P=.02). As the preirradiation growth rate increased, the probability of postirradiation expansion also increased. Overall, 24.1% of tumors were stable, 53.4% experienced shrinkage, and 22.5% experienced expansion. Predictors of no postirradiation tumor expansion included no prior surgery (P=.01) and slower tumor growth rate (P=.02). The control of tumors in NF2 patients was only 43%. Conclusions: Radiation therapy is an effective treatment for VS, but tumors that grow quickly preirradiation may be

  5. Pretreatment Growth Rate Predicts Radiation Response in Vestibular Schwannomas

    International Nuclear Information System (INIS)

    Purpose: Vestibular schwannomas (VS) are often followed without initial therapeutic intervention because many tumors do not grow and radiation therapy is associated with potential adverse effects. In an effort to determine whether maximizing initial surveillance predicts for later treatment response, the predictive value of preirradiation growth rate of VS on response to radiation therapy was assessed. Methods and Materials: Sixty-four patients with 65 VS were treated with single-fraction stereotactic radiation surgery or fractionated stereotactic radiation therapy. Pre- and postirradiation linear expansion rates were estimated using volumetric measurements on sequential magnetic resonance images (MRIs). In addition, postirradiation tumor volume change was classified as demonstrating shrinkage (ratio of volume on last follow-up MRI to MRI immediately preceding irradiation <80%), stability (ratio 80%-120%), or expansion (ratio >120%). The median pre- and postirradiation follow-up was 20.0 and 27.5 months, respectively. Seven tumors from neurofibromatosis type 2 (NF2) patients were excluded from statistical analyses. Results: In the 58 non-NF2 patients, there was a trend of correlation between pre- and postirradiation volume change rates (slope on linear regression, 0.29; P=.06). Tumors demonstrating postirradiation expansion had a median preirradiation growth rate of 89%/year, and those without postirradiation expansion had a median preirradiation growth rate of 41%/year (P=.02). As the preirradiation growth rate increased, the probability of postirradiation expansion also increased. Overall, 24.1% of tumors were stable, 53.4% experienced shrinkage, and 22.5% experienced expansion. Predictors of no postirradiation tumor expansion included no prior surgery (P=.01) and slower tumor growth rate (P=.02). The control of tumors in NF2 patients was only 43%. Conclusions: Radiation therapy is an effective treatment for VS, but tumors that grow quickly preirradiation may be

  6. Influence of water relations and growth rate on plant element uptake and distribution

    Energy Technology Data Exchange (ETDEWEB)

    Greger, Maria [Stockholm Univ. (Sweden). Dept. of Botany

    2006-02-15

    Plant uptake of Ni, Sr, Mo, Cs, La, Th, Se, Cl and I was examined to determine how plant water relations and growth rate influence the uptake and distribution of these elements in the studied plants. The specific questions were how water uptake and growth rate influenced the uptake of various nuclides and how transpiration influenced translocation to the shoot. The knowledge gained will be used in future modelling of radionuclide leakage from nuclear waste deposits entering the ecosystem via plants. The plant studied was willow, Salix viminalis, a common plant in the areas suggested for waste disposal; since there can be clone variation, two different clones having different uptake properties for several other heavy metals were used. The plants were grown in nutrient solution and the experiments on 3-month-old plants were run for 3 days. Polyethylene glycol was added to the medium to decrease the water uptake rate, a fan was used to increase the transpiration rate, and different light intensities were used to produce different growth rates. Element concentration was analysed in roots and shoots. The results show that both the uptake and distribution of various elements are influenced in different ways and to various extents by water flow and plant growth rate, and that it is not possible from the chemical properties of these elements to know how they will react. However, in most cases increased growth rate diluted the concentration of the element in the tissue, reduced water uptake reduced the element uptake, while transpiration had no effect on the translocation of elements to the shoot. The clones did not differ in terms of either the uptake or translocation of the elements, except that I was not taken up and translocated to the shoot in one of the clones when the plant water flow or growth rate was too low. Not all of the elements were found in the plant in the same proportions as they had been added to the nutrient solution.

  7. Influence of water relations and growth rate on plant element uptake and distribution

    International Nuclear Information System (INIS)

    Plant uptake of Ni, Sr, Mo, Cs, La, Th, Se, Cl and I was examined to determine how plant water relations and growth rate influence the uptake and distribution of these elements in the studied plants. The specific questions were how water uptake and growth rate influenced the uptake of various nuclides and how transpiration influenced translocation to the shoot. The knowledge gained will be used in future modelling of radionuclide leakage from nuclear waste deposits entering the ecosystem via plants. The plant studied was willow, Salix viminalis, a common plant in the areas suggested for waste disposal; since there can be clone variation, two different clones having different uptake properties for several other heavy metals were used. The plants were grown in nutrient solution and the experiments on 3-month-old plants were run for 3 days. Polyethylene glycol was added to the medium to decrease the water uptake rate, a fan was used to increase the transpiration rate, and different light intensities were used to produce different growth rates. Element concentration was analysed in roots and shoots. The results show that both the uptake and distribution of various elements are influenced in different ways and to various extents by water flow and plant growth rate, and that it is not possible from the chemical properties of these elements to know how they will react. However, in most cases increased growth rate diluted the concentration of the element in the tissue, reduced water uptake reduced the element uptake, while transpiration had no effect on the translocation of elements to the shoot. The clones did not differ in terms of either the uptake or translocation of the elements, except that I was not taken up and translocated to the shoot in one of the clones when the plant water flow or growth rate was too low. Not all of the elements were found in the plant in the same proportions as they had been added to the nutrient solution

  8. Concurrent growth rate and transcript analyses reveal essential gene stringency in Escherichia coli.

    Directory of Open Access Journals (Sweden)

    Shan Goh

    Full Text Available BACKGROUND: Genes essential for bacterial growth are of particular scientific interest. Many putative essential genes have been identified or predicted in several species, however, little is known about gene expression requirement stringency, which may be an important aspect of bacterial physiology and likely a determining factor in drug target development. METHODOLOGY/PRINCIPAL FINDINGS: Working from the premise that essential genes differ in absolute requirement for growth, we describe silencing of putative essential genes in E. coli to obtain a titration of declining growth rates and transcript levels by using antisense peptide nucleic acids (PNA and expressed antisense RNA. The relationship between mRNA decline and growth rate decline reflects the degree of essentiality, or stringency, of an essential gene, which is here defined by the minimum transcript level for a 50% reduction in growth rate (MTL(50. When applied to four growth essential genes, both RNA silencing methods resulted in MTL(50 values that reveal acpP as the most stringently required of the four genes examined, with ftsZ the next most stringently required. The established antibacterial targets murA and fabI were less stringently required. CONCLUSIONS: RNA silencing can reveal stringent requirements for gene expression with respect to growth. This method may be used to validate existing essential genes and to quantify drug target requirement.

  9. Influence of oxygen transfer on Pseudomonas putida effects on growth rate and biodesulfurization capacity.

    Science.gov (United States)

    Escobar, S; Rodriguez, A; Gomez, E; Alcon, A; Santos, V E; Garcia-Ochoa, Felix

    2016-04-01

    The growth rate and desulfurization capacity accumulated by the cells during the growth of Pseudomonas putida KTH2 under different oxygen transfer conditions in a stirred and sparged tank bioreactor have been studied. Hydrodynamic conditions were changed using different agitation conditions. During the culture, several magnitudes associated to growth, such as the specific growth rate, the dissolved oxygen concentration and the carbon source consumption have been measured. Experimental results indicate that cultures are influenced by the fluid dynamic conditions into the bioreactor. An increase in the stirrer speed from 400 to 700 rpm has a positive influence on the cell growth rate. Nevertheless, the increase of agitation from 700 to 2000 rpm hardly has any influence on the growth rate. The effect of fluid dynamics on the cells development of the biodesulfurization (BDS) capacity of the cells during growth is different. The activities of the intracellular enzymes involved in the 4S pathway change with dissolved oxygen concentration. The enzyme activities have been evaluated in cells at several growth time and different hydrodynamic conditions. An increase of the agitation from 100 to 300 rpm has a positive influence on the development of the overall BDS capacity of the cells during growth. This capacity shows a decrease for higher stirrer speeds and the activity of the enzymes monooxygenases DszC and DszA decreases dramatically. The highest value of the activity of DszB enzyme was obtained with cells cultured at 100 rpm, while this activity decreases when the stirrer speed was increased higher than this value. PMID:26762940

  10. Crystal Growth Rate Dispersion: A Predictor of Crystal Quality in Microgravity?

    Science.gov (United States)

    Kephart, Richard D.; Judge, Russell A.; Snell, Edward H.; vanderWoerd, Mark J.

    2003-01-01

    In theory macromolecular crystals grow through a process involving at least two transport phenomena of solute to the crystal surface: diffusion and convection. In absence of standard gravitational forces, the ratio of these two phenomena can change and explain why crystal growth in microgravity is different from that on Earth. Experimental evidence clearly shows, however, that crystal growth of various systems is not equally sensitive to reduction in gravitational forces, leading to quality improvement in microgravity for some crystals but not for others. We hypothesize that the differences in final crystal quality are related to crystal growth rate dispersion. If growth rate dispersion exists on Earth, decreases in microgravity, and coincides with crystal quality improvements then this dispersion is a predictor for crystal quality improvement. In order to test this hypothesis, we will measure growth rate dispersion both in microgravity and on Earth and will correlate the data with previously established data on crystal quality differences for the two environments. We present here the first crystal growth rate measurement data for three proteins (lysozyme, xylose isomerase and human recombinant insulin), collected on Earth, using hardware identical to the hardware to be used in microgravity and show how these data correlate with crystal quality improvements established in microgravity.

  11. The FTIR spectroscopy investigation of the cellular components of cassava after sensitization with plant growth promoting rhizobacteria, [i]Bacillus subtili[/i]s CaSUT007

    OpenAIRE

    Buensateai, Natthiya; Thumanu, Kanjana; Sompong, Mathukorn; Athinuwat, Dusit; Prathuangwong, Sutruedee

    2012-01-01

    Publication Inra prise en compte dans l'analyse bibliométrique des publications scientifiques mondiales sur les Fruits, les Légumes et la Pomme de terre. Période 2000-2012. http://prodinra.inra.fr/record/256699 To evaluate the response of cassava stakes to plant growth promoting rhizobacteria, Bacillus subtilis CaSUT007, the changes in cellular compositions and phytohormone were investigated using the fourier transform infrared (FTIR) and high-performance liquid chromatography (HPLC) appro...

  12. Cellular energy allocation and scope for growth in the estuarine mysid Neomysis integer (Crustacea: Mysidacea) following chlorpyrifos exposure: a method comparison

    OpenAIRE

    Verslycke, T.; Roast, S.D.; Widdows, J.; Jones, M B; Janssen, C. R.

    2004-01-01

    Mysids (Crustacea: Mysidacea) are used routinely in acute toxicity testing to evaluate the comparative toxicity of chemicals to aquatic organisms. The need for sublethal endpoints that provide comprehensive understanding of the potential impacts of toxicants to natural populations has resulted in examination of several physiological responses in mysid shrimp, including scope for growth (SFG) and cellular energy allocation (CEA). Both assays, based on the concept that energy in excess of that ...

  13. Analysis of the cellular uptake and nuclear delivery of insulin-like growth factor binding protein-3 in human osteosarcoma cells

    OpenAIRE

    Laich, A; Matscheski, A.; Mück, C.; Ferrando-May, E.; H. Pircher; Ebner, H L; Micutkova, L.; Huber, L A; M. Hermann; Offerdinger, M.; Hess, M. W.; Jansen-Dürr, P; Zwerschke, W.

    2010-01-01

    Insulin-like growth factor (IGF) binding protein-3 (IGFBP-3) is an important regulator of cell proliferation and survival, which plays an important role in a variety of epithelial cancers, including prostate cancer, cervical cancer and breast cancer. IGFBP-3 was described as a tumor suppressor in the prostate and identified as a functional cellular target for the E7 oncoprotein of human papillomaviruses. IGFBP-3 interacts with IGF-I outside the cell; however, IGF-independent actions of IGFBP...

  14. Trace incorporation of heavy water reveals slow and heterogeneous pathogen growth rates in cystic fibrosis sputum

    Science.gov (United States)

    Kopf, Sebastian H.; Sessions, Alex L.; Cowley, Elise S.; Reyes, Carmen; Van Sambeek, Lindsey; Hu, Yang; Orphan, Victoria J.; Kato, Roberta; Newman, Dianne K.

    2016-01-01

    Effective treatment for chronic infections is undermined by a significant gap in understanding of the physiological state of pathogens at the site of infection. Chronic pulmonary infections are responsible for the morbidity and mortality of millions of immunocompromised individuals worldwide, yet drugs that are successful in laboratory culture are far less effective against pathogen populations persisting in vivo. Laboratory models, upon which preclinical development of new drugs is based, can only replicate host conditions when we understand the metabolic state of the pathogens and the degree of heterogeneity within the population. In this study, we measured the anabolic activity of the pathogen Staphylococcus aureus directly in the sputum of pediatric patients with cystic fibrosis (CF), by combining the high sensitivity of isotope ratio mass spectrometry with a heavy water labeling approach to capture the full range of in situ growth rates. Our results reveal S. aureus generation times with a median of 2.1 d, with extensive growth rate heterogeneity at the single-cell level. These growth rates are far below the detection limit of previous estimates of CF pathogen growth rates, and the rates are slowest in acutely sick patients undergoing pulmonary exacerbations; nevertheless, they are accessible to experimental replication within laboratory models. Treatment regimens that include specific antibiotics (vancomycin, piperacillin/tazobactam, tobramycin) further appear to correlate with slow growth of S. aureus on average, but follow-up longitudinal studies must be performed to determine whether this effect holds for individual patients.

  15. Empirical Analysis of Non-Performing Loans Trend and Growth Rate in Nigerian Banking System

    Directory of Open Access Journals (Sweden)

    Aniefiok Akpan Umoren

    2016-04-01

    Full Text Available Increasing trend in Non-performing loans (NPLs adversely affected availability of credits to economic agents in all sectors of the economy thereby constraining financial intermediation and economic activities. The study examined the trend and growth rates of NPLs in the Nigerian banking system during the major banking policy reforms regimes namely: pre-consolidation (1979 – 2004 and post consolidation era (2005 – 2014. Time series data collected were analyzed using descriptive and regression analyses. Results indicated irregular fluctuations in NPLs’ trend in both periods. This result suggested prevalent of high credit risk and corresponding reduction in lending capability of banks in the economy. Regression estimates of NPLs’ trend in the two regimes showed significant negative growth rates. This implies that, financial policies implemented in the country yielded positive impacts over time. NPLs assumed an exponential growth rate of -1.39% and -15.55% during the pre and post consolidated eras respectively. An average exponential growth rate of -5.2% was obtained during the entire period. Quadratic trend analysis revealed that, increase influence of time variable significantly reduced NPLs during pre- consolidation regime and the entire period considered. However, this influence was stagnated during post consolidation period. Based on the result, it is recommended that, prudent lending coupled with swift and orderly clean-up of banking system loan portfolios should be adopted to decelerate NPLs trend and growth rate in Nigeria. Time is an important element in designing and implementing any banking and macroeconomic policy.

  16. Rapid growth reduces cold resistance: evidence from latitudinal variation in growth rate, cold resistance and stress proteins.

    Directory of Open Access Journals (Sweden)

    Robby Stoks

    Full Text Available BACKGROUND: Physiological costs of rapid growth may contribute to the observation that organisms typically grow at submaximal rates. Although, it has been hypothesized that faster growing individuals would do worse in dealing with suboptimal temperatures, this type of cost has never been explored empirically. Furthermore, the mechanistic basis of the physiological costs of rapid growth is largely unexplored. METHODOLOGY/PRINCIPAL FINDING: Larvae of the damselfly Ischnura elegans from two univoltine northern and two multivoltine southern populations were reared at three temperatures and after emergence given a cold shock. Cold resistance, measured by chill coma recovery times in the adult stage, was lower in the southern populations. The faster larval growth rates in the southern populations contributed to this latitudinal pattern in cold resistance. In accordance with their assumed role in cold resistance, Hsp70 levels were lower in the southern populations, and faster growing larvae had lower Hsp70 levels. Yet, individual variation in Hsp70 levels did not explain variation in cold resistance. CONCLUSIONS/SIGNIFICANCE: WE PROVIDE EVIDENCE FOR A NOVEL COST OF RAPID GROWTH: reduced cold resistance. Our results indicate that the reduced cold resistance in southern populations of animals that change voltinism along the latitudinal gradient may not entirely be explained by thermal selection per se but also by the costs of time constraint-induced higher growth rates. This also illustrates that stressors imposed in the larval stage may carry over and shape fitness in the adult stage and highlights the importance of physiological costs in the evolution of life-histories at macro-scales.

  17. Environmental effects of the growth rate of intertidal invertebrates and some implications for foraging waders

    Science.gov (United States)

    Wanink, Jan H.; Zwarts, Leo

    The paper describes effects of intertidal height and sediment type on growth rate of the bivalves Cerastoderma edule, Macoma balthica, Mya arenaria, Mytilus edulis and Scrobicularia plana, and of the worms Arenicola marina, Nephtys hombergii and Nereis diversicolor in the eastern part of the Dutch Wadden Sea. In most species, exposure time was negatively correlated with length growth, although interfering effects of sediment type could not be ruled out. When controlled for the effects of exposure time, clay content of the sediment appeared to affect the growth of all species, but in different ways. The variation was related to the foraging methods of the invertebrates. Foraging waders may use the spatial variation in growth rate of the invertebrates to optimize the exploitation of individual cohorts.

  18. Spatial distribution of soda straws growth rates of the Coufin Cave (Vercors, France

    Directory of Open Access Journals (Sweden)

    Perrette Yves

    2010-07-01

    Full Text Available The Choranche Cave system (Vercors, France is an excellent locality for measuring the growth rates of large numbers soda straws. This is especially the case for the Coufin Cave, as enlargement of the cave entrance in 1875 led to a change in stalactite color from brown to white, thus providing a reliable chronomarker. The date of this brown-to-white calcite transition has been confirmed by lamina counting. We measured and georeferenced the growth-lengths of 306 soda straws in a 1m2 area of the roof of the Coufin Cave entrance chamber. Because of the very slow and sometimes inexistent water feeding of those stalactites, hydrochemistry analysis were not achieved and drop rate effect on growth were neglected; this study is based on a geomorphological and geostatistical work. By measuring a large number of soda straws in a very small area for which most of the parameters affecting stalactite growth could be considered uniform, and because flow rates are very slow (frequencies are always superior to 1 drop per half hour, we could ascribe differences in growth rates to variations in the global increase of water flow through the unsaturated matrix. Statistical and geostatistical analyses of the measurements showed that this set of similarly shaped stalactites actually consisted of three Gaussian populations with different mean growth rates: fast growth rate (FGR- mean of 0.92 mm.y-1, medium growth rate (MGR- mean of 0.47 mm.y-1 and low growth rate (LGR- 0.09 mm.y-1. Plotting the lengths and spatial distribution of the 20 longest FGR soda straws revealed that there is a rough pattern to the water flow through the cave roof. Even if no direction is statisticaly different from others, the observed directional pattern is consistent with local and regional tectonic observations. Plots of the spatial distribution of the soda straws show that FGR soda straws follow lines of regional geological stress, whereas MGR and LGR soda straws are more dispersed.

  19. Calcite growth-rate inhibition by fulvic acid and magnesium ion—Possible influence on biogenic calcite formation

    Science.gov (United States)

    Reddy, Michael M.

    2012-01-01

    Increases in ocean surface water dissolved carbon dioxide (CO2) concentrations retard biocalcification by reducing calcite supersaturation (Ωc). Reduced calcification rates may influence growth-rate dependent magnesium ion (Mg) incorporation into biogenic calcite modifying the use of calcifying organisms as paleoclimate proxies. Fulvic acid (FA) at biocalcification sites may further reduce calcification rates. Calcite growth-rate inhibition by FA and Mg, two common constituents of seawater and soil water involved in the formation of biogenic calcite, was measured separately and in combination under identical, highly reproducible experimental conditions. Calcite growth rates (pH=8.5 and Ωc=4.5) are reduced by FA (0.5 mg/L) to 47% and by Mg (10−4 M) to 38%, compared to control experiments containing no added growth-rate inhibitor. Humic acid (HA) is twice as effective a calcite growth-rate inhibitor as FA. Calcite growth rate in the presence of both FA (0.5 mg/L) and Mg (10−4 M) is reduced to 5% of the control rate. Mg inhibits calcite growth rates by substitution for calcium ion at the growth site. In contrast, FA inhibits calcite growth rates by binding multiple carboxylate groups on the calcite surface. FA and Mg together have an increased affinity for the calcite growth sites reducing calcite growth rates.

  20. Plasma deposition of boron films with high growth rate and efficiency using carborane

    International Nuclear Information System (INIS)

    The injection of carborane (C2B10H12) on the PISCES-B linear plasma device has been used to produce boron containing films on various target species. Film growth rates achieved are extremely high (up to 30 nm/s) compared to those typically found for glow discharges (∼0.01 nm/s). For low-Z target materials (C and Al) the film production is highly efficient, with the boron film growth rate comparable to the incident ion flux and the injection rate of boron atoms. The boron to carbon ratio is 3.0-3.6 for these films. Similarly high growth rates (∼10 nm/s) are obtained with high-Z target (W), but with lower deposition efficiency and higher B/C film ratio. The high film growth rate/efficiency are apparently linked to the high degree of carborane ionization and dissociation caused by the ∼40 eV PISCES-B plasma, compared with T<1 eV plasmas of glow discharges. This technique opens the possibility of continuously producing protective B films in thermonuclear devices where net erosion rates approach 10 nm/s

  1. Are international growth rates constrained by the balance of payments? A comment on Professor Thirlwall

    Directory of Open Access Journals (Sweden)

    J.S.L. MCCOMBIE

    2013-12-01

    Full Text Available In a recent article A.P. Thirlwall derived what he termed a “fundamental law” which he argued explains the disparate post-war growth rates of advanced countries. In this note, the author takes issue with Thirlwall’s model, showing that together with the empirical evidence it is not capable of discriminating between the demand and the supply orientated approaches to growth.

  2. Horizon Instability of Extremal Kerr Black Holes: Nonaxisymmetric Modes and Enhanced Growth Rate

    CERN Document Server

    Casals, Marc; Zimmerman, Peter

    2016-01-01

    We show that the horizon instability of the extremal Kerr black hole is associated with a singular branch point in the Green function at the superradiant bound frequency. We study generic initial data supported away from the horizon and find an enhanced growth rate due to nonaxisymmetric modes. The growth is controlled by the conformal weight of each mode. We speculate on connections to near-extremal black holes and holographic duality.

  3. Simple Predicting Method for Fatigue Crack Growth Rate Based on Tensile Strength of Carbon Steel

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Three types of fatigue tests for an annealed carbon steel containing carbon of 0.42 % were carried out on smooth specimens and specimens with a small blind hole in order to investigate the fatigue crack growth law. A simple predicting method for crack growth rates has been proposed involving strength σb and the relation between cyclic stress and strain. The validity of proposed method has been confirmed by experiments on several carbon steels with different loadings.

  4. Can Uzbekistan Economy Retain Its High Growth Rates? Scenarios of Economic Development in 2015-30

    OpenAIRE

    Popov, Vladimir

    2014-01-01

    Uzbekistan in recent 10 years is an extremely successful economy – high growth (8%), low domestic and international debt, undervalued exchange rate, relatively even distribution of income, creation from scratch competitive export oriented auto industry. It is important though to avoid “dizziness from success” and to envisage possible growth traps in the future. This paper discusses two unfavourable scenarios – negative terms of trade shock due to the decline in cotton, gas and gold prices (a ...

  5. Economic Growth, Financial Depth and Lending Rate Nexus: A Case of Oil Dependant Economy

    OpenAIRE

    Najeeb Muhammad Nasir; Nasir Ali; Imran Khokhar

    2014-01-01

    This research empirically investigates the long and short run causal relationships between economic growth, financial depth and lending rate in the unique economic setup of Saudi Arabia where 92% of total GDP comes from oil exports. Study uses two proxies for financial depth namely liquid liability indicator and banks claim to the private sector to GDP ratio, while economic growth is measured by real GDP per capita. This study intends to get answers for such questions as, if financial depth e...

  6. Poor correlation between phytoplankton community growth rates and nutrient concentration in the sea

    OpenAIRE

    Regaudie-de-gioux, A.; Sal, S; Á. López-Urrutia

    2015-01-01

    Nutrient availability is one of the major factors regulating marine productivity and phytoplankton community structure. While the response of phytoplankton species to nutrient variation is relatively well known, that of phytoplankton community remains unclear. We question whether phytoplankton community growth rates respond to nutrient concentration in a similar manner to phytoplankton species composing the community, that is, following Monod's model. Data on in situ marine community growth r...

  7. The role of dose rate in radiation cancer risk: evaluating the effect of dose rate at the molecular, cellular and tissue levels using key events in critical pathways following exposure to low LET radiation

    Science.gov (United States)

    Brooks, Antone L.; Hoel, David G.; Preston, R. Julian

    2016-01-01

    Abstract Purpose: This review evaluates the role of dose rate on cell and molecular responses. It focuses on the influence of dose rate on key events in critical pathways in the development of cancer. This approach is similar to that used by the U.S. EPA and others to evaluate risk from chemicals. It provides a mechanistic method to account for the influence of the dose rate from low-LET radiation, especially in the low-dose region on cancer risk assessment. Molecular, cellular, and tissues changes are observed in many key events and change as a function of dose rate. The magnitude and direction of change can be used to help establish an appropriate dose rate effectiveness factor (DREF). Conclusions: Extensive data on key events suggest that exposure to low dose-rates are less effective in producing changes than high dose rates. Most of these data at the molecular and cellular level support a large (2–30) DREF. In addition, some evidence suggests that doses delivered at a low dose rate decrease damage to levels below that observed in the controls. However, there are some data human and mechanistic data that support a dose-rate effectiveness factor of 1. In summary, a review of the available molecular, cellular and tissue data indicates that not only is dose rate an important variable in understanding radiation risk but it also supports the selection of a DREF greater than one as currently recommended by ICRP (2007) and BEIR VII (NRC/NAS 2006). PMID:27266588

  8. Slow Growth Rates of Amazonian Trees: Consequences for Carbon Sequestration and Forest Management.

    Science.gov (United States)

    Vieira, S. A.; Camargo, P. B.; Selhorst, D.; Chambers, J.; Higuchi, N.; Martinelli, L. A.; Trumbore, S.

    2004-12-01

    Growth rates for tropical forest trees estimated from radiocarbon ages and dendrometer measurements illustrate differences in forest age and structure among three sites located in the eastern, central and western Amazon basin. Although growth rates vary dramatically among individual trees overall the slowest growing trees (averaging \\sim0.1mm yr-1 as opposed to 0.3mm yr-1 diameter increment) are found in the central Amazon. Small individuals (DBH \\500 yr are encountered at all sites. Only \\sim2MgC ha-1 year-1, or \\SIM7% of annual photosynthesis, is allocated to growth of living wood at the eastern and central Amazon sites. Rates of C allocation to stem growth are similar across the three sites we studied because slowest growth occurs at the central Amazon site that has highest stem density and greatest biomass. Extrapolating our growth increment data to forest stand, we estimate the mean age of individual trees is \\SIM350 years in the central Amazon but \\SIM200\\-250 years in the other two areas. The mean age of C making up the trees has a smaller range of \\SIM250\\-310 years, because of the greater fraction of biomass in larger individuals in the eastern and western Amazon sites. These residence times for C are longer than those of 100\\-180 years obtained by simply dividing the total biomass C by the rate of C allocation to new wood for the same reason. We estimate that >20% of trees at all sites should have ages >300 years, and that maximum tree ages of >1000 years, though not common, are in accord with the growth rates we find. The fact that many Amazon trees attain ages greater than several centuries should be accounted for in management practices in these forests.

  9. Toroidicity and shape dependence of peeling mode growth rates in axisymmetric toroidal plasmas

    International Nuclear Information System (INIS)

    The growth rate of the peeling mode instability with large toroidal mode number is calculated for general axisymmetric toroidal plasmas, including tokamaks and the spherical torus (ST) equilibia by using formalism presented by Connor et al. Analytic equilibia with non-zero edge current density and quasi-uniform current profiles are assumed. It is found that in sharp D-shape tokamak plasma, the derivative of the safety factor with respect to the poloidal flux becomes very large, making the perturbed poloidal motion very large, in turn making a significant reduction of the growth rate of the peeling mode, similar to the X-point effect in diverted plasma. The large aspect ratio effect is also studied, which reduces the growth rate further. (physics of gases, plasmas, and electric discharges)

  10. ANALYSIS OF TUITION GROWTH RATES BASED ON CLUSTERING AND REGRESSION MODELS

    Directory of Open Access Journals (Sweden)

    Long Cheng

    2016-07-01

    Full Text Available Tuition plays a significant role in determining whether a student could afford higher education, which is one of the major driving forces for country development and social prosperity. So it is necessary to fully understand what factors might affect the tuition and how they affect it. However, many existing studies on the tuition growth rate either lack sufficient real data and proper quantitative models to support their conclusions, or are limited to focus on only a few factors that might affect the tuition growth rate, failing to make a comprehensive analysis. In this paper, we explore a wide variety of factors that might affect the tuition growth rate by use of large amounts of authentic data and different quantitative methods such as clustering and regression models.

  11. Investigation of the growth rate for joint fast breeder reactor and light water reactor operation

    International Nuclear Information System (INIS)

    An investigation of fuel consumption and breeding characteristics of FBR-LWR joint operation is presented. The FBR operates in a closed cycle with joint-reprocessing of core and blanket material. The LWR-portion that runs on FBR plutonium operates in an open cycle. The growth rate of the system is defined based upon the fact that the discharge from the system will make up a fraction of an identical system; the system growth rate is found to have an almost linear dependence on the fraction of the LWR fed by plutonium from the FBR. The LWR growth rate, which is negative, is a constant and represents the fraction of the fuel burnt in the LWR-fraction that runs on FBR plutonium per year

  12. STRATIFIED MODEL FOR ESTIMATING FATIGUE CRACK GROWTH RATE OF METALLIC MATERIALS

    Institute of Scientific and Technical Information of China (English)

    YANG Yong-yu; LIU Xin-wei; YANG Fan

    2005-01-01

    The curve of relationship between fatigue crack growth rate and the stress strength factor amplitude represented an important fatigue property in designing of damage tolerance limits and predicting life of metallic component parts. In order to have a morereasonable use of testing data, samples from population were stratified suggested by the stratified random sample model (SRAM). The data in each stratum corresponded to the same experiment conditions. A suitable weight was assigned to each stratified sample according to the actual working states of the pressure vessel, so that the estimation of fatigue crack growth rate equation was more accurate for practice. An empirical study shows that the SRAM estimation by using fatigue crack growth rate data from different stoves is obviously better than the estimation from simple random sample model.

  13. Measurement of fatigue crack growth rate in pipe and pipe weld

    International Nuclear Information System (INIS)

    Striation spacing on the fracture surface developed during fatigue crack growth in pipes and pipe welds have been examined under scanning electron microscope (SEM). Striation spacing was measured on the fracture surface in maximum depth (radial) and surface (circumferential) direction at several locations. Striation spacing increases with crack growth in thickness (depth) direction of pipe and pipe weld. Local direction of striation spacing is different from the global direction of crack growth in cracked pipe. Striation spacing was compared with the conventionally evaluated crack growth rate where crack growth was measured using Alternate Current Potential Difference (ACPD) based instrument. Striation spacing is marginally lower for carbon steel and higher for stainless steel in comparison to da/dN in the Paris regime (evaluated from 'a Vs N' plot). Striation spacing form fracture surface of pipe was also compared with those measured on CT specimen. (author)

  14. Non-monotonic growth rates of sawtooth precursors evidenced with a new method on ASDEX Upgrade

    Science.gov (United States)

    Vezinet, D.; Igochine, V.; Weiland, M.; Yu, Q.; Gude, A.; Meshcheriakov, D.; Sertoli, M.; the Asdex Upgrade Team; the EUROfusion MST1 Team

    2016-08-01

    This paper describes a new method to derive, from soft x-ray (SXR) tomography, robust estimates of the core displacement, growth rate and frequency of a 1/1 sawtooth crash precursor. The method is valid for very peaked SXR profiles and is robust against both the inversion algorithm and the presence of tungsten in a rotating plasma. Three typical ASDEX Upgrade crashes are then analysed. In all cases a postcursor is observed, suggesting incomplete reconnection. Despite different dynamics, in all three cases the growth rate of the core displacement shows similar features. First, it is not constant, supporting the idea of non-linear growth. Second, it can be divided into clearly identified phases with quasi-constant growth rates, suggesting sudden change of growth regime rather than smooth transitions. Third, its evolution is non-monotonic, with phases of accelerated growth followed by damped phases. This damping is interpreted for two cases respectively as an effect of fast ions and of mode coupling, based on the result of a MHD simulation. The mode frequency is observed in all cases to be closely related to the plasma bulk rotation profile, with little or no visible effect of the electron diamagnetic drift frequency. The onset criterion could not be clearly identified and it is shown that the role of the pressure gradient is not as expected from a naive extrapolation of the linear stability theory.

  15. Effects of varying media, temperature, and growth rates on the intracellular concentrations of yeast amino acids.

    Science.gov (United States)

    Martínez-Force, E; Benítez, T

    1995-01-01

    Variations of the yeast free amino acid pool under different culture conditions were studied in two Saccharomyces strains, the laboratory haploid strain S288C and the industrial fermentative yeast IFI256. The internal amino acid pool of both strains was measured when grown in laboratory (minimal and complete) versus semiindustrial (molasses with or without added biotin and/or diammonium phosphate) media, in fermentable (glucose, fructose, sucrose) versus respirable (glycerol) carbon sources, in different temperatures (22, 30, and 37 degrees C), pHs (2.0-4.75), and growth rates (0.018-0.24 h-1) in continuous culture, and at different phases of the growth curve in batch culture (lag, exponential, early and late stationary). Results indicated that environmental conditions, particularly the presence of amino acids in the media, enormously influenced the intracellular amino acid concentration. Higher values were detected in molasses than in laboratory media and in fermentable carbon sources (glucose, fructose, sucrose) than in glycerol. Variations in the amino acid pool along the growth curve were greater at 37 degrees C than at other temperatures; in all cases, the highest values were measured at the beginning of the exponential phase. In continuous culture and at different growth rates, intracellular free amino acid concentrations increased by 3-10-fold when the growth rate was lower than 0.05 h-1, representing 20-35% of the total (free plus protein) amino acid content and indicating that amino acid yield was a partly growth-linked parameter. PMID:7654310

  16. A Generalized Preferential Attachment Model for Business Firms Growth Rates: I. Empirical Evidence

    CERN Document Server

    Pammolli, F; Buldyrev, S V; Riccaboni, M; Matia, K; Yamasaki, K; Stanley, H E; Pammolli, Fabio; Fu, Dongfeng; Riccaboni, Massimo; Matia, Kaushik; Yamasaki, Kazuko

    2006-01-01

    We introduce a model of proportional growth to explain the distribution $P(g)$ of business firm growth rates. The model predicts that $P(g)$ is Laplace in the central part and depicts an asymptotic power-law behavior in the tails with an exponent $\\zeta=3$. Because of data limitations, previous studies in this field have been focusing exclusively on the Laplace shape of the body of the distribution. We test the model at different levels of aggregation in the economy, from products, to firms, to countries, and we find that the its predictions are in good agreement with empirical evidence on both growth distributions and size-variance relationships.

  17. Measuring selection in human populations using the growth rate per generation.

    Science.gov (United States)

    Ewbank, Douglas

    2016-04-19

    Estimates of the speed of evolution between generations depend on the association between individual traits and a measure of fitness. The two most frequently used measures of fitness are the net reproduction rate and the 1-year growth factor implied by the fertility and mortality rates. Results based on the two lead to very different results. The reason is that the 1-year growth factor is not a measure of change between generations. Therefore, studies of changes between generations should use the amount of growth over the length of a generation. This is especially important for studies of human populations because of the long length of generation. In addition, estimates based on a single year's growth are overly sensitive to data on individuals who fail to reproduce. The effects of using a generational measure are demonstrated using data from Kenya and Ukraine. These results demonstrate that using a 1-year growth rate to measure fitness leads to estimates that understate the rate at which evolution changes the characteristics of a human population. PMID:27022075

  18. Airborne measurements of nucleation mode particles I: coastal nucleation and growth rates

    Directory of Open Access Journals (Sweden)

    C. D. O'Dowd

    2007-01-01

    Full Text Available A light aircraft was equipped with a bank of Condensation Particle Counters (CPCs (50% cut from 3–5.4–9.6 nm and a nano-Scanning Mobility Particle Sizer (nSMPS and deployed along the west coast of Ireland, in the vicinity of Mace Head. The objective of the exercise was to provide high resolution micro-physical measurements of the coastal nucleation mode in order to map the spatial extent of new particle production regions and to evaluate the evolution, and associated growth rates of the coastal nucleation-mode aerosol plume. Results indicate that coastal new particle production is occurring over most areas along the land-sea interface with peak concentrations at the coastal plume-head in excess of 106 cm−3. Pseudo-Lagrangian studies of the coastal plume evolution illustrated significant growth of new particles to sizes in excess of 8 nm approximately 10 km downwind of the source region. Close to the plume head (<1 km growth rates can be as high as 123–171 nm h−1, decreasing gradually to 53–72 nm h−1 at 3 km. Further along the plume, at distances up to 10 km, the growth rates are calculated to be 17–32 nm h−1. Growth rates of this magnitude suggest that after a couple of hours, coastal nucleation mode particles can reach significant sizes where they can contribution to the regional aerosol loading.

  19. Effects of lowered pH on marine phytoplankton growth rates

    DEFF Research Database (Denmark)

    Berge, Terje; Daugbjerg, Niels; Andersen, Betinna Balling;

    2010-01-01

    concentration of seawater. Ocean acidification may potentially both stimulate and reduce primary production by marine phytoplankton. Data are scarce on the response of marine phytoplankton growth rates to lowered pH/increased CO2. Using the acid addition method to lower the seawater pH and manipulate the...... carbonate system, we determined in detail the lower pH limit for growth rates of 2 model species of common marine phytoplankton. We also tested whether growth and production rates of 6 other common species of phytoplankton were affected by ocean acidification (lowered to pH 7.0). The lower pH limits for...... statistically similar in the pH range of ~7.0 to 8.5. Our results and literature reports on growth at lowered pH indicate that marine phytoplankton in general are resistant to climate change in terms of ocean acidification, and do not increase or decrease their growth rates according to ecological relevant...

  20. Collaborative Project: Understanding the Chemical Processes tat Affect Growth rates of Freshly Nucleated Particles

    Energy Technology Data Exchange (ETDEWEB)

    McMurry, Peter [Univ. of Minnesota, Minneapolis, MN (United States); Smuth, James [University Corporation for Atmospheric Research, Irvine, CA (United States)

    2015-11-12

    This final technical report describes our research activities that have, as the ultimate goal, the development of a model that explains growth rates of freshly nucleated particles. The research activities, which combine field observations with laboratory experiments, explore the relationship between concentrations of gas-phase species that contribute to growth and the rates at which those species are taken up. We also describe measurements of the chemical composition of freshly nucleated particles in a variety of locales, as well as properties (especially hygroscopicity) that influence their effects on climate.

  1. Growth rate of peeling mode in the near separatrix region of diverted tokamak plasma

    International Nuclear Information System (INIS)

    An analytical expression of the peeling mode in the near separatrix region of diverted tokamak plasma is derived. It is shown that in diverted plasmas both with single and double X points, though the perturbed potential energy of the unstable peeling mode tends to be large, its growth rate becomes very small due to the even larger kinetic energy. Compared to some recent studies that give qualitatively correct results about this growth rate, our result is directly related with the diverted equilibrium quantities suitable for application to realistic experiments. (physics of gases, plasmas, and electric discharges)

  2. A study on the rate of contribution of education investment to the economic growth in China

    Institute of Scientific and Technical Information of China (English)

    Fan Bo-nai; Lai Xiong-xiang

    2006-01-01

    There is an evident bi-directional causality relationship between education investment and economic growth based on an analysis of statistics from 1952 to 2003 released by the State Statistics Bureau.A generalized difference regression model is set up to investigate the relationship between the two.Studies show that the rate of contribution of education investment to economic growth was 24.4 percent from 1952 to 2003.Further examination indicates that after the market-oriented economy restructuring,this rate increased by a wide margin of 7 percent,from 22.8 percent to 29.7 percent.

  3. Intuitive calculation of the relativistic Rayleigh-Taylor instability linear growth rate

    CERN Document Server

    Bret, A

    2011-01-01

    The Rayleigh-Taylor instability is a key process in many fields of Physics ranging from astrophysics to inertial confinement fusion. It is usually analyzed deriving the linearized fluid equations, but the physics behind the instability is not always clear. Recent works on this instability allow for an very intuitive understanding of the phenomenon and for a straightforward calculation of the linear growth rate. In this Letter, it is shown that the same reasoning allows for a direct derivation of the relativistic expression of the linear growth rate for an incompressible fluid.

  4. Growth rates of interchange modes in the dense z-pinch and gas blanket effects

    International Nuclear Information System (INIS)

    A class of models of the dense z-pinch in which the bulk of the plasma is neutrally stable against interchange is studied. At a radius a the plasma is abruptly terminated and surrounded by a gas blanket. Instability results from the surface current necessary to maintain pressure balance at the plasma-gas interface. A single dispersion relation applies to all models in this class and shows two effects of the gas blanket in reducing growth rate. (1) Partial support of plasma pressure by external gas pressure reduces the driving force for the instability, and (2) mass loading of the relatively dense neutral gas reduces growth rate

  5. Effects of distributions of growth rates on recrystallization kinetics and microstructure

    DEFF Research Database (Denmark)

    Godiksen, Rasmus Brauner; Schmidt, Søren; Juul Jensen, Dorte

    2007-01-01

    The effects on recrystallization kinetics and microstructure of growth rate distributions rather than a single growth rate for recrystallizing grains were investigated by geometric simulations. The grains were set to grow as spheres with radii r = At1-alpha. The results show that distributions in A...... and alpha may produce significant changes in the microstructure and texture, whereas only distributions in alpha may change the overall evolution in kinetics represented by V-v(t) by completely changing the shape of the kinetics curve. (c) 2007 Acta Materialia Inc. Published by Elsevier Ltd. All...

  6. Growth rates in modern speleothems from Santana Cave, Brazil, by the 210Pb-method

    International Nuclear Information System (INIS)

    The Santana Cave is located at the Upper Ribeira Touristic State Park (PETAR-Parque Estadual Turístico do Alto Ribeira) in southern São Paulo State, Brazil. This paper describes 210Pb activity concentration data in soda straw stalactites samples collected at Salão das Flores in Santana Cave that is a fossil tributary of the cave river. Non-expensive alpha counting following some analytical steps for extracting and depositing 210Po were used for providing the 210Pb data. In the analyzed samples, 210Pb values of increasingly older samples fitted an exponential curve, thus suggesting that the production of 210Pb has been constant with time. Also, the near-ideal fit indicated that the growth was uniform and there was no break in the continuous growth. The soda straw growth rates were determined from the best fit to the exponential curve through the 210Pb activity concentration. The results of the measurements allowed estimate a longitudinal rate corresponding to 1.3 mm/yr and a lateral rate of 0.01 mm/yr, which permitted calculate times of 70 years and 317–498 years for their formation, respectively. The lateral growth rate is compatible with values from studies of chemical weathering rates held under laboratory and natural conditions.

  7. Dependence of microstructures on growth rate in YBCO films by TFA-MOD method

    International Nuclear Information System (INIS)

    YBa2Cu3Oy (YBCO) films grown by starting solutions with Ba-poor (Y:Ba:Cu = 1:1.5:3, Ba/Y = 1.5) have been reported to perform higher Jc than that for YBCO films with stoichiometric one due to smaller and less pores in YBCO films by metal organic deposition (MOD) using tri-fluoroacetates (TFA). However, we have reported that a lot of non-reacted particles such as Y and Cu oxides were remained for the YBCO film surface grown by the precursors using Ba-poor solution. In this study, influences of YBCO growth rate on microstructures of the YBCO film were discussed to control microstructures of these second phase particles. As a result, microstructures of the YBCO film depended strongly on the YBCO growth rate, residues of Y and Cu oxides were dispersed randomly throughout the YBCO film grown at higher growth rate. Consequently, it was succeeded to control the segregated phases as seen in the previous YBCO film with Ba/Y = 1.5 at the film surface into the YBCO film. Jc of the YBCO film grown at higher rate was a value almost equal to that grown at previous growth rate.

  8. Survival, recruitment, and population growth rate of an important mesopredator: the northern raccoon.

    Science.gov (United States)

    Troyer, Elizabeth M; Cameron Devitt, Susan E; Sunquist, Melvin E; Goswami, Varun R; Oli, Madan K

    2014-01-01

    Populations of mesopredators (mid-sized mammalian carnivores) are expanding in size and range amid declining apex predator populations and ever-growing human presence, leading to significant ecological impacts. Despite their obvious importance, population dynamics have scarcely been studied for most mesopredator species. Information on basic population parameters and processes under a range of conditions is necessary for managing these species. Here we investigate survival, recruitment, and population growth rate of a widely distributed and abundant mesopredator, the northern raccoon (Procyon lotor), using Pradel's temporal symmetry models and >6 years of monthly capture-mark-recapture data collected in a protected area. Monthly apparent survival probability was higher for females (0.949, 95% CI = 0.936-0.960) than for males (0.908, 95% CI = 0.893-0.920), while monthly recruitment rate was higher for males (0.091, 95% CI = 0.078-0.106) than for females (0.054, 95% CI = 0.042-0.067). Finally, monthly realized population growth rate was 1.000 (95% CI = 0.996-1.004), indicating that our study population has reached a stable equilibrium in this relatively undisturbed habitat. There was little evidence for substantial temporal variation in population growth rate or its components. Our study is one of the first to quantify survival, recruitment, and realized population growth rate of raccoons using long-term data and rigorous statistical models. PMID:24901349

  9. Microscopic Rate Constants of Crystal Growth from Molecular Dynamic Simulations Combined with Metadynamics

    Directory of Open Access Journals (Sweden)

    Dániel Kozma

    2012-01-01

    Full Text Available Atomistic simulation of crystal growth can be decomposed into two steps: the determination of the microscopic rate constants and a mesoscopic kinetic Monte Carlo simulation. We proposed a method to determine kinetic rate constants of crystal growth. We performed classical molecular dynamics on the equilibrium liquid/crystal interface of argon. Metadynamics was used to explore the free energy surface of crystal growth. A crystalline atom was selected at the interface, and it was displaced to the liquid phase by adding repulsive Gaussian potentials. The activation free energy of this process was calculated as the maximal potential energy density of the Gaussian potentials. We calculated the rate constants at different interfacial structures using the transition state theory. In order to mimic real crystallization, we applied a temperature difference in the calculations of the two opposite rate constants, and they were applied in kinetic Monte Carlo simulation. The novelty of our technique is that it can be used for slow crystallization processes, while the simple following of trajectories can be applied only for fast reactions. Our method is a possibility for determination of elementary rate constants of crystal growth that seems to be necessary for the long-time goal of computer-aided crystal design.

  10. Tropical dendrochemistry: A novel approach for reconstructing seasonally-resolved growth rates from ringless tropical trees

    Science.gov (United States)

    Poussart, P. M.; Myneni, S. C.

    2005-12-01

    Although tropical forests play an active role in the global carbon cycle and are host to a variety of pristine paleoclimate archives, they remain poorly characterized as compared to other ecosystems on the planet. In particular, dating and reconstructing the growth rate history of tropical trees remains a challenge and continues to delay research efforts towards understanding tropical forest dynamics. Traditional dendrochronological techniques have found limited applications in the tropics because temperature seasonality is often too small to initiate the production of visible annual growth rings. Dendrometers, cambium scarring methods and sub-annual records of oxygen and carbon isotopes from tree cellulose may be used to estimate growth rate histories when growth rings are absent. However, dendrometer records rarely extend beyond the past couple of decades and the generation of seasonally-resolved isotopic records remains labour intensive, currently prohibiting the level of record replication necessary for statistical analysis. Here, we present evidence that Ca may also be used as a proxy for dating and reconstructing growth rates of trees lacking visible growth rings. Using the Brookhaven National Lab Synchrotron, we recover a radial record of cyclic variations in Ca from a Miliusa velutina tree from northern Thailand. We determine that the Ca cycles are seasonal based on a comparison between radiocarbon age estimates and a trace element age model, which agree within 2 years over the period of 1955 to 2000. The amplitude of the Ca annual cycle is significantly correlated with growth rate estimates, which are also correlated to the amount of dry season rainfall. The measurements at the Synchrotron are fast, non-destructive and require little sample preparation. Application of this technique in the tropics holds the potential to resolve longstanding questions about tropical forest dynamics and interannual to decadal changes in the carbon cycle.

  11. Etabolism in compensatory growth . III. The urea, glucose and C02 entry rates in animal undergoing compensatory growth

    Directory of Open Access Journals (Sweden)

    Pram Mahyudin

    1996-03-01

    Full Text Available Glucose (GER, Urea (UER and C02 (C02 ER entry rates were studied at four points in the growth curve viz: before feed restriction (PI after 8 weeks of feed restriction (P2, after 3 weeks (P3 and 15 weeks (P4 following resumption ofad libitum feeding. Sixteen Merino wethers were used and offerred pelleted lucerne (Medicago sativa ad libitum for 3 weeks; then they were divided into 2 groups of eight. Group I continued to be fed ad libitum and Group 11 was fed pelleted lucerne at half maintenance level for 8 weeks and then fed ad libitum until the end of experiment. During feed restriction (P2, UER, urinary urea and urea transferred from the blood to the gut were 74% lower in group II than those in group I due to the reduction of N intake . At P2 GER and C02ER were also lower (53% and 56%, respectively because of the reduction of available glucose precursor and metabolic rate. Similarly AV concentration difference of glucose, glucose taken up by the hind-limb muscle and the percentage of glucose taken up by muscle that was oxidised were reduced by 52%, 86% and 48%, respectively . When animals resumed ad libitum feeding, the components of urea entry rate (except plasma urea concentration, GER and C02ER were markedly increased indicating A switch to the anabolic mode, followed by increased glucose taken up and oxidised by the hind-limb muscle . The significance of glucose in muscle metabolism during compensatory growth was shown in the dramatic increase in the actual rate of glucose oxidation per unit muscle weight . It appears that the priority of usage of glucose taken up by muscle during compensatory growth is for oxidation to both C02 and lactate.

  12. The effect of dislocation cores on growth hillock vicinality and normal growth rates of KDP ?1 0 1? surfaces

    Science.gov (United States)

    De Yoreo, J. J.; Land, T. A.; Rashkovich, L. N.; Onischenko, T. A.; Lee, J. D.; Monovskii, O. V.; Zaitseva, N. P.

    1997-12-01

    We present results from atomic force microscopy measurements on KDP {1 0 1} faces which show that over the range of supersaturations, 3% ≤ σ ≤ 30%, the terrace widths on vicinal growth hillocks formed by dislocations are nearly independent of both supersaturation and dislocation structure, in contradiction to the predictions of simple BCF models. The data also show that, for Burgers vectors in excess of one unit step height, the dislocations generate hollow cores in accordance with theoretical predictions. Both analytical and numerical analyses are presented, which show that a model that takes into account the effect of these cores on the period of step rotation predicts a dependence of slope on supersaturation and Burgers vector, which is in good agreement with the experimental results. These calculations also show that the effect of the core perimeter on the step transit time dominates the effect of reduced step velocity due to stresses near the core. Consequently, a simple analytical expression can be used to describe the slope even in the case of anistropic step kinetics. Finally, the results are used to explain the reproducible character of macroscopic growth rates and to rescale data on growth rate as a function of temperature and supersturation onto a single curve.

  13. Growth rates and the prevalence and progression of scoliosis in short-statured children on Australian growth hormone treatment programmes

    Directory of Open Access Journals (Sweden)

    McPhee Ian

    2007-02-01

    Full Text Available Abstract Study design and aim This was a longitudinal chart review of a diverse group (cohort of patients undergoing HGH (Human Growth Hormone treatment. Clinical and radiological examinations were performed with the aim to identify the presence and progression of scoliosis. Methods and cohort 185 patients were recruited and a database incorporating the age at commencement, dose and frequency of growth hormone treatment and growth charts was compiled from their Medical Records. The presence of any known syndrome and the clinical presence of scoliosis were included for analysis. Subsequently, skeletally immature patients identified with scoliosis were followed up over a period of a minimum four years and the radiologic type, progression and severity (Cobb angle of scoliosis were recorded. Results Four (3.6% of the 109 with idiopathic short stature or hormone deficiency had idiopathic scoliosis (within normal limits for a control population and scoliosis progression was not prospectively observed. 13 (28.8% of 45 with Turner syndrome had scoliosis radiologically similar to idiopathic scoliosis. 11 (48% of 23 with varying syndromes, had scoliosis. In the entire cohort, the growth rates of those with and without scoliosis were not statistically different and HGH treatment was not ceased because of progression of scoliosis. Conclusion In this study, there was no evidence of HGH treatment being responsible for progression of scoliosis in a small number of non-syndromic patients (four. An incidental finding was that scoliosis, similar to the idiopathic type, appears to be more prevalent in Turner syndrome than previously believed.

  14. Effect of reactor pressure on the growth rate and structural properties of GaN films

    Institute of Scientific and Technical Information of China (English)

    NI JinYu; HAO Yue; ZHANG JinCheng; YANG LinAn

    2009-01-01

    The effect of reactor pressure on the growth rate,surface morphology and crystalline quality of GaN films grown on sapphire by metalorganic chemical vapor deposition is studied.The results show that as the reactor pressure increases from 2500 to 20000 Pa,the GaN surface becomes rough and the growth rate of GaN films decreases.The rough surface morphology is associated with the initial high temperature GaN islands,which are large with low density due to low adatom surface diffusion under high reactor pressure.These islands prolong the occurrence of 2D growth mode and decrease the growth rate of GaN film.Meanwhile,the large GaN islands with low density lead to the reduction of threading dislocation density during subsequent island growth and coalescence,and consequently decrease the full width at half maximum of X-ray rocking curve of the GaN film.

  15. Temperature Effects on the Growth Rates and Photosynthetic Activities of Symbiodinium Cells

    Directory of Open Access Journals (Sweden)

    Widiastuti Karim

    2015-06-01

    Full Text Available Coral bleaching is caused by environmental stress and susceptibility to bleaching stress varies among types of coral. The physiological properties of the algal symbionts (Symbiodinium spp., especially extent of damage to PSII and its repair capacity, contribute importantly to this variability in stress susceptibility. The objective of the present study was to investigate the relationship between the growth rates and photosynthetic activities of six cultured strains of Symbiodinium spp. (clades A, B, C, D, and F at elevated temperature (33 °C. We also observed the recovery of photodamaged-PSII in the presence or absence of a chloroplast protein synthesis inhibitor (lincomycin. The growth rates and photochemical efficiencies of PSII (Fv/Fm decreased in parallel at high temperature in thermally sensitive strains, B-K100 (clade B followed by culture name and A-Y106, but not in thermally tolerant strains, F-K102 and D-K111. In strains A-KB8 and C-Y103, growth declined markedly at high temperature, but Fv/Fm decreased only slightly. These strains may reallocate energy from growth to the repair of damaged photosynthetic machineries or protection pathways. Alternatively, since recoveries of photo-damaged PSII at 33 °C were modest in strains A-KB8 and C-Y103, thermal stressing of other metabolic pathways may have reduced growth rates in these two strains. This possibility should be explored in future research efforts.

  16. The impact of disease on the survival and population growth rate of the Tasmanian devil.

    Science.gov (United States)

    Lachish, Shelly; Jones, Menna; McCallum, Hamish

    2007-09-01

    1. We investigated the impact of a recently emerged disease, Devil Facial Tumour Disease (DFTD), on the survival and population growth rate of a population of Tasmanian devils, Sarcophilus harrisii, on the Freycinet Peninsula in eastern Tasmania. 2. Cormack-Jolly-Seber and multistate mark-recapture models were employed to investigate the impact of DFTD on age- and sex-specific apparent survival and transition rates. Disease impact on population growth rate was investigated using reverse-time mark-recapture models. 3. The arrival of DFTD triggered an immediate and steady decline in apparent survival rates of adults and subadults, the rate of which was predicted well by the increase in disease prevalence in the population over time. 4. Transitions from healthy to diseased state increased with disease prevalence suggesting that the force of infection in the population is increasing and that the epidemic is not subsiding. 5. The arrival of DFTD coincided with a marked, ongoing decline in the population growth rate of the previously stable population, which to date has not been offset by population compensatory responses. PMID:17714271

  17. Diffusive boundary layers of the colony-forming plankton alga Phaeocystis sp - implications for nutrient uptake and cellular growth

    DEFF Research Database (Denmark)

    Ploug, H.; Stolte, W.; Jørgensen, BB

    1999-01-01

    The impact of colony formation on cellular nutrient supply was calculated for Phaeocystis in a turbulent environment using a diffusion-reaction model. The model included diffusive boundary layer as predicted by Sherwood numbers in mass transfer to a sphere. Literature values for nutrient uptake (...

  18. Final Report: "Collaborative Project. Understanding the Chemical Processes That Affect Growth Rates of Freshly Nucleated Particles"

    Energy Technology Data Exchange (ETDEWEB)

    Smith, James N. [NCAR, Boulder, CO (United States); McMurry, Peter H. [NCAR, Boulder, CO (United States)

    2015-11-12

    This final technical report describes our research activities that have, as the ultimate goal, the development of a model that explains growth rates of freshly nucleated particles. The research activities, which combine field observations with laboratory experiments, explore the relationship between concentrations of gas-phase species that contribute to growth and the rates at which those species are taken up. We also describe measurements of the chemical composition of freshly nucleated particles in a variety of locales, as well as properties (especially hygroscopicity) that influence their effects on climate. Our measurements include a self-organized, DOE-ARM funded project at the Southern Great Plains site, the New Particle Formation Study (NPFS), which took place during spring 2013. NPFS data are available to the research community on the ARM data archive, providing a unique suite observations of trace gas and aerosols that are associated with the formation and growth of atmospheric aerosol particles.

  19. Radiocarbon-Based Ages and Growth Rates of Bamboo Corals from the Gulf of Alaska

    Energy Technology Data Exchange (ETDEWEB)

    Roark, E B; Guilderson, T P; Flood-Page, S; Dunbar, R B; Ingram, B L; Fallon, S J; McCulloch, M

    2004-12-12

    Deep-sea coral communities have long been recognized by fisherman as areas that support large populations of commercial fish. As a consequence, many deep-sea coral communities are threatened by bottom trawling. Successful management and conservation of this widespread deep-sea habitat requires knowledge of the age and growth rates of deep-sea corals. These organisms also contain important archives of intermediate and deep-water variability, and are thus of interest in the context of decadal to century-scale climate dynamics. Here, we present {Delta}{sup 14}C data that suggest that bamboo corals from the Gulf of Alaska are long-lived (75-126 years) and that they acquire skeletal carbon from two distinct sources. Independent verification of our growth rate estimates and coral ages is obtained by counting seasonal Sr/Ca cycles and probable lunar cycle growth bands.

  20. Rate-dependent morphology of Li2O2 growth in Li-O2 batteries

    CERN Document Server

    Horstmann, B; Mitchell, R; Bessler, W G; Shao-Horn, Y; Bazant, M Z

    2013-01-01

    Compact solid discharge products enable energy storage devices with high gravimetric and volumetric energy densities, but solid deposits on active surfaces can disturb charge transport and induce mechanical stress. In this Letter we develop a nanoscale continuum model for the growth of Li2O2 crystals in lithium-oxygen batteries with organic electrolytes, based on a theory of electrochemical non-equilibrium thermodynamics originally applied to Li-ion batteries. As in the case of lithium insertion in phase-separating LiFePO4 nanoparticles, the theory predicts a transition from complex to uniform morphologies of Li2O2 with increasing current. Discrete particle growth at low discharge rates becomes suppressed at high rates, resulting in a film of electronically insulating Li2O2 that limits cell performance. We predict that the transition between these surface growth modes occurs at current densities close to the exchange current density of the cathode reaction, consistent with experimental observations.

  1. Growth rate of multiple intracranial hydatid cysts assessed by CT from the time of embolisation

    International Nuclear Information System (INIS)

    We report the case of a 25-year-old man with multiple bilateral hydatid cysts of the brain in whom we were able to assess the growth rate of the cysts on repeated examination. On average, the cysts increased in diameter by 1 cm per month. (orig.)

  2. A Study on the Rate of Contribution of Education Investment to the Economic Growth in China

    Science.gov (United States)

    Fan, Bo-nai; Lai, Xiong-xiang

    2006-01-01

    There is an evident bi-directional causality relationship between education investment and economic growth based on an analysis of statistics from 1952 to 2003 released by the State Statistics Bureau. A generalized difference regression model is set up to investigate the relationship between the two. Studies show that the rate of contribution of…

  3. Extracting growth rates from the non-laminated coralline sponge Astrosclera willeyana using "bomb" radiocarbon

    Energy Technology Data Exchange (ETDEWEB)

    Fallon, S; Guilderson, T

    2004-06-30

    Coralline sponges have the potential to fill in gaps in our understanding of subsurface oceanographic variability. However, one disadvantage they have compared to hermatypic reef building coral proxies is that they do not have annual density bands and need to be radiometrically dated for an age determination. To elucidate growth rate variability we have measured radiocarbon in 1 mm increments from Astrosclera willeyana sponges collected off the Central and Northern Great Barrier Reef (GBR) and from Truk in the Caroline Islands and compared these radiocarbon profiles to independently dated coral radiocarbon records. Growth rates of the GBR sponges average 1.2 {+-} 0.3 and 1.0 {+-} 0.3 mm yr{sup -1}, north and central respectively but can vary by a factor of two. The growth rate of the Truk sponge averages 1.2 {+-} 0.1 mm yr{sup -1}. These growth rates are significantly faster to those measured for other GBR Astrosclera willeyana sponges (0.2 mm yr{sup -1}) by Calcein staining (Woerheide 1988).

  4. STRONG LAW OF LARGE NUMBERS AND GROWTH RATE FOR NOD SEQUENCES

    Institute of Scientific and Technical Information of China (English)

    MA Song-lin; WANG Xue-jun

    2015-01-01

    In the paper, we get the precise results of Hájek-Rényi type inequalities for the par-tial sums of negatively orthant dependent sequences, which improve the results of Theorem 3.1 and Corollary 3.2 in Kim (2006) and the strong law of large numbers and strong growth rate for negatively orthant dependent sequences.

  5. Effect of temperature on fatigue crack growth rate in inconel 690

    International Nuclear Information System (INIS)

    The effect of temperature on fatigue crack growth rate in Inconel 690 steam generator tube was investigated at room temperature, 150 .deg. C, 300 .deg. C and 400 .deg. C in air environment. Fatigue tests was performed on compact tension(CT) specimens made to thickness 8mm. Heat treatment was performed to obtain various microstructures. Tests was conducted at load ratio 0.1, at frequency 10Hz using sinusoidal waveform. Crack length was monitored by compliance method using sensor probe. Tensile tests was performed to obtain yield strength for fatigue test at each testing temperature. Fracture modes were studied using scanning electron microscopy(SEM). Tensile properties of Inconel 690 were dependent on grain size and testing temperature. As temperature and grain size increased, yield strength decreased. At temperature above 300 .deg. C, the serrations which were an evidence of dynamic strain aging (DSA) were observed for all cases of materials. Fatigue crack growth rate decreased with increasing grain size. At low Δ K, grain size effect was significant at room temperature, which was due to roughness induced crack closure. With increasing temperature, fatigue crack growth rate increased and grain size effect decreased. Chormium carbides which have large size and semi-continuous distribution in the grain boundaries decreased fatigue crack growth rate

  6. Effect of temperature on microbial growth rate - thermodynamic analysis, the arrhenius and eyring-polanyi connection

    Science.gov (United States)

    The objective of this work is to develop a new thermodynamic mathematical model for evaluating the effect of temperature on the rate of microbial growth. The new mathematical model is derived by combining the Arrhenius equation and the Eyring-Polanyi transition theory. The new model, suitable for ...

  7. What is the Long Run Growth Rate of the East Asian Tigers?

    OpenAIRE

    Rao, B. Bhaskara; Tamazian, Artur; Singh, Rup

    2010-01-01

    New panel data estimates for the four East Asian Tigers show that the contribution of total factor productivity (TFP) to growth is much higher than past estimates. An extended production function with learning by doing implies that TFP is about 3.5% and these countries will grow at this rate in the long run.

  8. Measurements of coherent tune shifts and head-tail growth rates at the CERN SPS

    CERN Document Server

    Zorzano-Mier, M P; Burkhardt, H; Cornelis, Karel; Zimmermann, Frank; Papaphilippou, Y

    2000-01-01

    As part of an ongoing effort to monitor SPS impedance changes with regard to LHC, the coherent tune shifts and head-tail growth rates in the SPS were measured for single proton bunches at 26 GeV. From these measurements the real and imaginary components of the transverse broadband impedance can be estimated.

  9. Quantitative physiology of Lactococcus lactis at extreme low-growth rates

    NARCIS (Netherlands)

    Ercan, O.; Smid, E.J.; Kleerebezem, M.

    2013-01-01

    This paper describes the metabolic adaptation of Lactococcus lactis during the transition from a growing to a non-growing state using retentostat cultivation. Under retentostat cultivation, the specific growth rate decreased from 0.025 h-1 to 0.0001 h-1 in 42 days, while doubling time increased to m

  10. Wavelength dependence of the linear growth rate of the Es layer instability

    Directory of Open Access Journals (Sweden)

    R. B. Cosgrove

    2007-06-01

    Full Text Available It has recently been shown, by computation of the linear growth rate, that midlatitude sporadic-E (Es layers are subject to a large scale electrodynamic instability. This instability is a logical candidate to explain certain frontal structuring events, and polarization electric fields, which have been observed in Es layers by ionosondes, by coherent scatter radars, and by rockets. However, the original growth rate derivation assumed an infinitely thin Es layer, and therefore did not address the short wavelength cutoff. Also, the same derivation ignored the effects of F region loading, which is a significant wavelength dependent effect. Herein is given a generalized derivation that remedies both these short comings, and thereby allows a computation of the wavelength dependence of the linear growth rate, as well as computations of various threshold conditions. The wavelength dependence of the linear growth rate is compared with observed periodicities, and the role of the zeroth order meridional wind is explored. A three-dimensional paper model is used to explain the instability geometry, which has been defined formally in previous works.

  11. Stress corrosion crack growth rates in NiCrMoV turbine disc steels

    International Nuclear Information System (INIS)

    Stress corrosion crack growth rates were obtained from precracked WOL specimens in simulated turbine environments - pure NaOH solutions, dilute NaOH-NaCl solutions and pure water. Tests were performed at 157 C on steels with yield strength in the range 706-1124 MPa

  12. Growth rate regulates membrane fluidity and membrane cold adaptation in .i.Bacillus subtilis./i

    Czech Academy of Sciences Publication Activity Database

    Beranová, J.; Jemiola-Rzeminska, M.; Elhottová, Dana; Strzalka, K.; Konopásek, I.

    2007-01-01

    Roč. 48, - (2007), s. 85. ISSN 0009-0646. [Kongres Československé společnosti mikrobiologické /24./. 02.10.2007-05.10.2007, Liberec] Institutional research plan: CEZ:AV0Z60660521 Keywords : growth rate * membrane fluidity * membrane cold adaptation Subject RIV: EH - Ecology, Behaviour

  13. Capitalizing on the Dynamic Features of Excel to Consider Growth Rates and Limits

    Science.gov (United States)

    Taylor, Daniel; Moore-Russo, Deborah

    2012-01-01

    It is common for both algebra and calculus instructors to use power functions of various degrees as well as exponential functions to examine and compare rates of growth. This can be done on a chalkboard, with a graphing calculator, or with a spreadsheet. Instructors often are careful to connect the symbolic and graphical (and occasionally the…

  14. A methodology to study cyclic debond growth at constant mode-mixity and energy release rate

    DEFF Research Database (Denmark)

    Quispitupa, Amilcar; Berggreen, Christian; Carlsson, Leif A.

    2010-01-01

    structures under well controlled cyclic energy release rate and mode-mixity. The proposed methodology uses the mixed mode bending (MMB) sandwich specimen and MMB test rig. Crack length measurements are based on an analytically available compliance expression. Accurate fatigue crack growth measurements and...

  15. Predicting Lexical Density Growth Rate in Young Children with Autism Spectrum Disorders

    Science.gov (United States)

    Yoder, Paul J.

    2006-01-01

    Purpose: The purpose of this longitudinal correlational study was to test whether an environmental variable and 4 child variables predicted growth rate of number of different nonimitative words used (i.e., lexical density). Method: Thirty-five young (age range = 21-54 months) children with autism spectrum disorders (ASD) who were initially…

  16. Growth rate of Usnea aurantiacoatra (Jacq. Bory on Fildes Peninsula, Antarctica and its climatic background.

    Directory of Open Access Journals (Sweden)

    Ying Li

    Full Text Available The ages of a fruticose lichen of Usnea aurantiacoatra (Jacq. Bory, from Fildes Peninsula, King George Island, Southwest Antarctic, were determined by radiocarbon (14C, and it is 1993-1996 at bottom and 2006-2007 at top of the lichen branch. The growth rates of U. aurantiacoatra calculated are 4.3 to 5.5 mm year(-1 based on its length and ages. The comparisons show that the growth rates of U. aurantiacoatra are higher than those of U. antarctica (0.4 to 1.1 mm year(-1. The growth rates of fruticose lichens are always higher, usually >2 mm year(-1, than those of crustose ones, usually <1 mm year(-1, in polar areas. A warming trend on Fildes Peninsula is recorded in the period from 1969 to 2010 obviously: the mean annual temperature rose from -2.75 to -1.9°C and the average temperature of summer months from 0.95 to 1.4°C, as well as the average temperature of winter months from -6.75 to -5.5°C. The alteration of lichen growth rates in polar areas may respond to the climatic and environmental changes, and the lichens may act as bio-monitor of natural condition.

  17. LIDAR OBSERVATIONS OF MIXED LAYER DYNAMICS: TESTS OF PARAMETERIZED ENTRAINMENT MODELS OF MIXED LAYER GROWTH RATE

    Science.gov (United States)

    Lidar measurements of the atmospheric boundary layer height, the entrainment zone, wind speed and direction, ancillary temperature profiles and surface flux data were used to test current parameterized entrainment models of mixed layer growth rate. Six case studies under clear ai...

  18. Gene expression of fibroblast growth factors in human gliomas and meningiomas: demonstration of cellular source of basic fibroblast growth factor mRNA and peptide in tumor tissues.

    OpenAIRE

    J.A. Takahashi; Mori, H.; Fukumoto, M; Igarashi, K; Jaye, M; Oda, Y.; Kikuchi, H; Hatanaka, M

    1990-01-01

    The growth autonomy of human tumor cells is considered due to the endogenous production of growth factors. Transcriptional expression of candidates for autocrine stimulatory factors such as basic fibroblast growth factor (FGF), acidic FGF, and transforming growth factor type beta were determined in human brain tumors. Basic FGF was expressed abundantly in 17 of 18 gliomas, 20 of 22 meninglomas, and 0 of 5 metastatic brain tumors. The level of mRNA expression of acidic FGF in gliomas was signi...

  19. Are physicians profit or rent seekers? Some evidence from state economic growth rates.

    Science.gov (United States)

    Reilly, Mary; Santerre, Rexford E

    2013-01-01

    Previous research has debated whether physicians act as profit- or rent-seekers. We argue that these two models of physician behavior can be tested by observing empirically the relationship between physician density and economic growth rates. A direct (inverse) relationship provides evidence for the profit-seeking (rent-seeking) theory of physician behavior. We empirically examine the impact of physician density on the economic growth of all US states over the period from 1973 to 2009. The empirical analysis generally finds a statistically significant and direct relationship between physician density and the growth of gross state product. The results are robust with respect to state- and time-fixed effects, individual state time trends, and 2SLS (two-stage least squares) estimation. Thus, in support of the profit-seeking theory of physician behavior, the findings reveal that physicians generally have a positive impact on the growth of the US economy. PMID:24199520

  20. Spectral conversion of light for enhanced microalgae growth rates and photosynthetic pigment production.

    Science.gov (United States)

    Mohsenpour, Seyedeh Fatemeh; Richards, Bryce; Willoughby, Nik

    2012-12-01

    The effect of light conditions on the growth of green algae Chlorella vulgaris and cyanobacteria Gloeothece membranacea was investigated by filtering different wavelengths of visible light and comparing against a model daylight source as a control. Luminescent acrylic sheets containing violet, green, orange or red dyes illuminated by a solar simulator produced the desired wavelengths of light for this study. From the experimental results the highest specific growth rate for C. vulgaris was achieved using the orange range whereas violet light promoted the growth of G. membranacea. Red light exhibited the least efficiency in conversion of light energy into biomass in both strains of microalgae. Photosynthetic pigment formation was examined and maximum chlorophyll-a production in C. vulgaris was obtained by red light illumination. Green light yielded the best chlorophyll-a production in G. membranacea. The proposed illumination strategy offers improved microalgae growth without resorting to artificial light sources, reducing energy use and costs of cultivation. PMID:23023239

  1. Effect of band-overload on fatigue crack growth rate of HSLA steel

    Science.gov (United States)

    Abhinay, S. V.; Tenduwe, Om Prakash; Kumar, Ajit; Dutta, K.; Verma, B. B.; Ray, P. K.

    2015-02-01

    Fatigue crack growth behavior is important parameter of structural materials. This parameters can be used to predict their life, service reliability and operational safety in different conditions. The material used in this investigation is an HSLA steel. In this investigation effect of single overload and band-overload on fatigue crack growth of same steel are studied using compact tension (CT) specimens under mode-I condition and R=0.3. It is observed that overload and band-overload applications resulted retardation on the fatigue crack growth rate in most of the cases. It is also noticed that maximum retardation took place on application of seven successive overload cycles. Application of ten and more overload cycles caused no crack growth retardation.

  2. The effect of differential growth rates across plants on spectral predictions of physiological parameters.

    Directory of Open Access Journals (Sweden)

    Tal Rapaport

    Full Text Available Leaves of various ages and positions in a plant's canopy can present distinct physiological, morphological and anatomical characteristics, leading to complexities in selecting a single leaf for spectral representation of an entire plant. A fortiori, as growth rates between canopies differ, spectral-based comparisons across multiple plants--often based on leaves' position but not age--becomes an even more challenging mission. This study explores the effect of differential growth rates on the reflectance variability between leaves of different canopies, and its implication on physiological predictions made by widely-used spectral indices. Two distinct irrigation treatments were applied for one month, in order to trigger the formation of different growth rates between two groups of grapevines. Throughout the experiment, the plants were physiologically and morphologically monitored, while leaves from every part of their canopies were spectrally and histologically sampled. As the control vines were constantly developing new leaves, the water deficit plants were experiencing growth inhibition, resulting in leaves of different age at similar nodal position across the treatments. This modification of the age-position correlation was characterized by a near infrared reflectance difference between younger and older leaves, which was found to be exponentially correlated (R(2 = 0.98 to the age-dependent area of intercellular air spaces within the spongy parenchyma. Overall, the foliage of the control plant became more spectrally variable, creating complications for intra- and inter-treatment leaf-based comparisons. Of the derived indices, the Structure-Insensitive Pigment Index (SIPI was found indifferent to the age-position effect, allowing the treatments to be compared at any nodal position, while a Normalized Difference Vegetation Index (NDVI-based stomatal conductance prediction was substantially affected by differential growth rates. As various

  3. Process for high growth rate and high superconducting properties of REBCO single crystals

    International Nuclear Information System (INIS)

    Process developments for both higher growth rate and superconducting properties are two main objectives of RE1Ba2Cu3O7-δ (REBCO or RE123) single crystal growth. In this paper, we will review several processes for increasing growth rate and achieving higher Tc REBCO superconductors. There are two effective methods to enhance the growth rate. One is to grow single crystals under high oxygen partial pressure, the other is to partially or completely replace Y by RE elements with higher solubilities in the Ba-Cu-O solution, for instance RE=Nd, Sm. Using these methods the growth rate was increased. The unprecendently large REBCO single crystals with the size 25 x 25 mm2 on the a-b plane and up to 20 mm in thickness were obtained. Regarding superconductivity, the critical temperature Tc of about 93 K was achieved from the Y123 single crystals both grown under air and 1 atm oxygen pressure, indicating that Tc is insensitive to the growth atmosphere of the oxygen pressure in the YBCO system. Furthermore, the high Tc of about 95 K NdBCO superconductors with a sharp transition was obtained by using Ba-rich liquid (Ba:Cu ratio=0.75-0.80 of solvent), suggesting that the liquid composition is an important thermodynamic parameter for controlling Tc. Moreover, the partial substitution RE (RE=Nd, Sm) at the Y sites up to 30% shows no obvious reduction of Tc remaining at about 91±1 K. (orig.)

  4. Consequences of complex environments: Temperature and energy intake interact to influence growth and metabolic rate.

    Science.gov (United States)

    Stahlschmidt, Zachary R; Jodrey, Alicia D; Luoma, Rachel L

    2015-09-01

    The field of comparative physiology has a rich history of elegantly examining the effects of individual environmental factors on performance traits linked to fitness (e.g., thermal performance curves for locomotion). However, animals live in complex environments wherein multiple environmental factors co-vary. Thus, we investigated the independent and interactive effects of temperature and energy intake on the growth and metabolic rate of juvenile corn snakes (Pantherophis guttatus) in the context of shifts in complex environments. Unlike previous studies that imposed constant or fluctuating temperature regimes, we manipulated the availability of preferred thermal microclimates (control vs. relatively warm regimes) for eight weeks and allowed snakes to behaviorally thermoregulate among microclimates. By also controlling for energy intake, we demonstrate an interactive effect of temperature and energy on growth-relevant temperature shifts had no effect on snakes' growth when energy intake was low and a positive effect on growth when energy intake was high. Thus, acclimation to relatively warm thermal options can result in increased rates of growth when food is abundant in a taxon in which body size confers fitness advantages. Temperature and energy also interactively influenced metabolic rate-snakes in the warmer temperature regime exhibited reduced metabolic rate (O2 consumption rate at 25 °C and 30 °C) if they had relatively high energy intake. Although we advocate for continued investigation into the effects of complex environments on other traits, our results indicate that warming may actually benefit important life history traits in some taxa and that metabolic shifts may underlie thermal acclimation. PMID:25899738

  5. Growth and yield responses of broccoli cultivars to different rates of nitrogen at western Chitwan, Nepal

    DEFF Research Database (Denmark)

    Giri, Raj Kumar; Sharma, Moha Datta; Shakya, Santa Man;

    2013-01-01

    A field experiment was conducted with the objective to determine the optimum rate of nitrogen (N) fertilizer for effective growth and yield of two varieties of broccoli in southern plain of Nepal. The experiment was laid out with two-factorial completely random block design (RCBD) comprising two...... varieties of broccoli (Calabrese and Green Sprouting) and five N rates (0, 50, 100, 150 and 200 kg ha-1) with three replication in each treatment combinations. The effects of variety and N rate on total curd yield were significant but the interaction effect was non-significant. Green Sprouting produced 11...

  6. Endosulfan induced changes in growth rate, pigment composition and photosynthetic activity of mosquito fern Azolla microphylla

    Directory of Open Access Journals (Sweden)

    Raja W.

    2012-11-01

    Full Text Available This paper is the first in a series reporting a study on the effects of different concentrations of insecticide, Endosulfan (0-600ppm was premeditated on 5th day after insecticide exposure with respect to growth rate, pigment composition and photosynthetic activity of Azolla microphylla under laboratory conditions which become non-target organism in the rice fields. Endosulfan inhibited the relative growth rate, pigment content and photosynthetic O2 evolution. Phycocyanin was main target followed by carotenoid and total chlorophyll. Significant increase in pigment, flavonoid and Anthocyanin was noticed after six days of treatment. In contrast to the photosynthetic activity, the rate of respiration in Azolla microphylla was increased significantly. Our results show that Endosulfan at normally recommended field rates and intervals are seldom deleterious to the beneficial and Eco friendly Azolla microphylla and their activities and thus in turn suppress plant growth and development. Phytotoxity of Azolla microphylla can be minimized by restrictions on application, timing, method and rate of application.

  7. Bridgman Solidification of Concentrated GaInSb Alloys with Variable Growth Rate

    International Nuclear Information System (INIS)

    Experimental works and numerical simulations on concentrated Ga1-xInxSb alloys directional solidification at high crucible pulling rates, show a damping solutal effect on the thermally driven convection which leads to a significant increase of the chemical heterogeneity of the sample and of the solid-liquid interface curvature. Analytical calculations which give a quantitative description of the solutal effect, show that the melt convection damping can be avoided if low pulling rates of the crucible are used for the growth process. A Bridgman growth method, which uses a variable pulling rate in order to reduce the damping solutal effect and to improve the axial chemical homogeneity of the sample, is numerically investigated. The growth process can be started at high pulling rates which are reduced progressively during the solidification. From the numerical modeling, it is found that the axial and radial variations of solute concentration as well as the interface curvature are maintained at lower values when variables pulling rates are used for Bridgman solidification of high doped alloys

  8. Measurement of bacterial growth rates in subsurface sediments using the incorporation of tritiated thymidine into DNA.

    Science.gov (United States)

    Thorn, P M; Ventullo, R M

    1988-07-01

    Microbial growth rates in subsurface sediment from three sites were measured using incorporation of tritiated thymidine into DNA. Sampling sites included Lula, Oklahoma, Traverse City, Michigan, and Summit Lake, Wisconsin. Application of the thymidine method to subsurface sediments required (1) thymidine concentrations greater than 125 nM, (2) incubation periods of less than 4 hours, (3) addition of SDS and EDTA for optimum macromolecular extraction, and (4) DNA purification, in order to accurately measure the rate of thymidine incorporation into DNA. Macromolecule extraction recoveries, as well as the percentage of tritium label incorporated into the DNA fraction, were variable and largely dependent upon sediment composition. In general, sandy sediments yielded higher extraction recoveries and demonstrated a larger percentage of label incorporated into DNA than sediments that contained a high silt-clay component. Reported results also indicate that the acid-base hydrolysis procedure routinely used for macromolecular fractionation in water samples may not be routinely applicable to the modified sediment procedure where addition of SDS and EDTA are required for macromolecule extraction. Growth rates exhibited by subsurface communities are relatively slow, ranging from 5.1 to 10.2×10(5) cells g(-1) day(-1). These rates are 2-1,000-fold lower than growth rates measured in surface sediments. These data lend support to the supposition that subsurface microbial communities are nutritionally stressed. PMID:24201529

  9. Effect of different carrier gases and their flow rates on the growth of carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Tewari, Aarti; Sharma, Suresh C. [Department of Applied Physics, Delhi Technological University (DTU), Shahbad Daulatpur, Bawana Road, Delhi 110 042 (India)

    2015-04-15

    The present paper examines the effect of different carrier gases and their flow rates on the growth of carbon nanotubes (CNTs). A theoretical model is developed incorporating the charging rate of the carbon nanotube, kinetics of all the plasma species, and the growth rate of the CNTs because of diffusion and accretion of ions on the catalyst nanoparticle. The three different carrier gases, i.e., argon (Ar), ammonia, and nitrogen, are considered in the present investigation, and flow rates of all the three carrier gases are varied individually (keeping the flow rates of hydrocarbon and hydrogen gas constant) to investigate the variations in the number densities of hydrocarbon and hydrogen ions in the plasma and their consequent effects on the height and radius of CNT. Based on the results obtained, it is concluded that Ar favors the formation of CNTs with larger height and radius whereas ammonia contributes to better height of CNT but decreases the radius of CNT, and nitrogen impedes both the height and radius of CNT. The present work can serve to the better understanding of process parameters during growth of CNTs by a plasma enhanced chemical vapor deposition process.

  10. Warming, soil moisture, and loss of snow increase Bromus tectorum’s population growth rate

    Directory of Open Access Journals (Sweden)

    Aldo Compagnoni

    2014-01-01

    Full Text Available Abstract Climate change threatens to exacerbate the impacts of invasive species. In temperate ecosystems, direct effects of warming may be compounded by dramatic reductions in winter snow cover. Cheatgrass (Bromus tectorum is arguably the most destructive biological invader in basins of the North American Intermountain West, and warming could increase its performance through direct effects on demographic rates or through indirect effects mediated by loss of snow. We conducted a two-year experimental manipulation of temperature and snow pack to test whether 1 warming increases cheatgrass population growth rate and 2 reduced snow cover contributes to cheatgrass’ positive response to warming. We used infrared heaters operating continuously to create the warming treatment, but turned heaters on only during snowfalls for the snowmelt treatment. We monitored cheatgrass population growth rate and the vital rates that determine it: emergence, survival and fecundity. Growth rate increased in both warming and snowmelt treatments. The largest increases occurred in warming plots during the wettest year, indicating that the magnitude of response to warming depends on moisture availability. Warming increased both fecundity and survival, especially in the wet year, while snowmelt contributed to the positive effects of warming by increasing survival. Our results indicate that increasing temperature will exacerbate cheatgrass impacts, especially where warming causes large reductions in the depth and duration of snow cover.

  11. No Effect of the Transforming Growth Factor {beta}1 Promoter Polymorphism C-509T on TGFB1 Gene Expression, Protein Secretion, or Cellular Radiosensitivity

    Energy Technology Data Exchange (ETDEWEB)

    Reuther, Sebastian; Metzke, Elisabeth [Laboratory of Radiobiology and Experimental Radiooncology, University Hospital Hamburg-Eppendorf, Hamburg (Germany); Bonin, Michael [Department of Medical Genetics, University of Tuebingen (Germany); Petersen, Cordula [Clinic of Radiotherapy and Radiooncology, University Hospital Hamburg-Eppendorf, Hamburg (Germany); Dikomey, Ekkehard, E-mail: dikomey@uke.de [Laboratory of Radiobiology and Experimental Radiooncology, University Hospital Hamburg-Eppendorf, Hamburg (Germany); Raabe, Annette [Laboratory of Radiobiology and Experimental Radiooncology, University Hospital Hamburg-Eppendorf, Hamburg (Germany)

    2013-02-01

    Purpose: To study whether the promoter polymorphism (C-509T) affects transforming growth factor {beta}1 gene (TGFB1) expression, protein secretion, and/or cellular radiosensitivity for both human lymphocytes and fibroblasts. Methods and Materials: Experiments were performed with lymphocytes taken either from 124 breast cancer patients or 59 pairs of normal monozygotic twins. We used 15 normal human primary fibroblast strains as controls. The C-509T genotype was determined by polymerase chain reaction-restriction fragment length polymorphism or TaqMan single nucleotide polymorphism (SNP) genotyping assay. The cellular radiosensitivity of lymphocytes was measured by G0/1 assay and that of fibroblasts by colony assay. The amount of extracellular TGFB1 protein was determined by enzyme-linked immunosorbent assay, and TGFB1 expression was assessed via microarray analysis or reverse transcription-polymerase chain reaction. Results: The C-509T genotype was found not to be associated with cellular radiosensitivity, neither for lymphocytes (breast cancer patients, P=.811; healthy donors, P=.181) nor for fibroblasts (P=.589). Both TGFB1 expression and TGFB1 protein secretion showed considerable variation, which, however, did not depend on the C-509T genotype (protein secretion: P=.879; gene expression: lymphocytes, P=.134, fibroblasts, P=.605). There was also no general correlation between TGFB1 expression and cellular radiosensitivity (lymphocytes, P=.632; fibroblasts, P=.573). Conclusion: Our data indicate that any association between the SNP C-509T of TGFB1 and risk of normal tissue toxicity cannot be ascribed to a functional consequence of this SNP, either on the level of gene expression, protein secretion, or cellular radiosensitivity.

  12. Evaluation of fatigue-crack growth rates by polynomial curve fitting. [Ti alloy plate

    Science.gov (United States)

    Davies, K. B.; Feddersen, C. E.

    1973-01-01

    Fundamental characterization of the constant-amplitude fatigue crack propagation is achieved by an analysis of the rate of change of crack length with change in number of applied loading cycles, defining the rate values such that they are consistent with the basic assumption of smoothness and continuity in the fatigue crack growth process. The technique used to satisfy the analytical conditions and minimize the effects of local material anomalies and experimental errors is that of fitting a smooth curve to the entire set of basic data by least square regression. This yields a well-behaved function relating the number of cycles to the crack length. By taking the first derivative of the function, the crack growth rate is obtained for each point. The class of curve fitting functions used in the analysis is the polynomial of degree n.

  13. Study of gypsum crystal nucleation and growth rates in simulated flue gas desulfurization liquors. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Randolph, A.D.; Etherton, D.

    1981-06-01

    The kinetics of gypsum crystal nucleation and growth rates were measured in flue gas desulfurization (FGD) scrubber liquors. Variables studied were parent seed crystal size and mass; the organic additives citric acid, adipic acid, sodium dodecylbenzene sulfonate, and Calgon CL246 polyacrylic acid formulation; and pH. Citric acid produced gypsum crystals with a more favorable columnar structure. Lower pH resulted in increased nucleation rates. Stable secondary nucleation was observed in the presence of retained parent gypsum seed crystals of size >150 ..mu..m. Growth and nucleation rates were correlated using reaction kinetic models. These kinetics were then used in rigorous computer simulations to predict crystal-size distribution (CSD) with different scrubber configurations. Scrubber process configurations employing classified product removal were calculated to produce a gypsum sludge having a mean particle size up to twice as large as the particle size with unclassified operation.

  14. Growth rates and production of heterotrophic bacteria and phytoplankton in the North Pacific subtropical gyre

    Science.gov (United States)

    Jones, David R.; Karl, David M.; Laws, Edward A.

    1996-10-01

    In field work conducted at 26°N, 155°W, in the North Pacific subtropical gyre, phytoplankton growth rates μp estimated from 14C labeling of chlorophyll a (chl a) averaged approximately one doubling per day in the euphotic zone (0-150 m). Microbial (microalgal plus heterotrophic bacterial) growth rates μm calculated from the incorporation of 3H-adenine into DNA were comparable to or exceeded phytoplankton growth rates at most depths in the euphotic zone. Photosynthetic rates averaged 727 mg C m -2 day -1 Phytoplankton carbon biomass, calculated from 14C labeling of chl a, averaged 7.2 mg m -3 in the euphotic zone. Vertical profiles of particulate DNA and ATP suggested that no more than 15% of particulate DNA was associated with actively growing cells. Heterotrophic bacterial carbon biomass was estimated from a two-year average at station ALOHA (22°45'N, 158°W) of flow cytometric counts of unpigmented, bacteria-size particles which bound DAPI on the assumption that 15% of the particles were actively growing cells and that heterotrophic bacterial cells contained 20 fg C cell -1 The heterotrophic bacterial carbon so calculated averaged 1.1 mg m -3 in the euphotic zone. Heterotrophic bacterial production was estimated to be 164 mg C m -2 day -1 or 23% of the calculated photosynthetic rate. Estimated heterotrophic bacterial growth rates averaged 0.97 day -1 in the euphotic zone and reached 4.7 day - at a depth of 20 m. Most heterotrophic bacterial production occurred in the upper 40 m of the euphotic zone, suggesting that direct excretion by phytoplankton, perhaps due to photorespiration or ultraviolet light effects, was a significant source of dissolved organic carbon for the bacteria.

  15. Influence of Ni Catalyst Layer and TiN Diffusion Barrier on Carbon Nanotube Growth Rate

    Directory of Open Access Journals (Sweden)

    Mérel Philippe

    2010-01-01

    Full Text Available Abstract Dense, vertically aligned multiwall carbon nanotubes were synthesized on TiN electrode layers for infrared sensing applications. Microwave plasma-enhanced chemical vapor deposition and Ni catalyst were used for the nanotubes synthesis. The resultant nanotubes were characterized by SEM, AFM, and TEM. Since the length of the nanotubes influences sensor characteristics, we study in details the effects of changing Ni and TiN thickness on the physical properties of the nanotubes. In this paper, we report the observation of a threshold Ni thickness of about 4 nm, when the average CNT growth rate switches from an increasing to a decreasing function of increasing Ni thickness, for a process temperature of 700°C. This behavior is likely related to a transition in the growth mode from a predominantly “base growth” to that of a “tip growth.” For Ni layer greater than 9 nm the growth rate, as well as the CNT diameter, variations become insignificant. We have also observed that a TiN barrier layer appears to favor the growth of thinner CNTs compared to a SiO2 layer.

  16. Improvement of growth rate of plants by bubble discharge in water

    Science.gov (United States)

    Takahata, Junichiro; Takaki, Koichi; Satta, Naoya; Takahashi, Katsuyuki; Fujio, Takuya; Sasaki, Yuji

    2015-01-01

    The effect of bubble discharge in water on the growth rate of plants was investigated experimentally for application to plant cultivation systems. Spinach (Spinacia oleracea), radish (Raphanus sativus var. sativus), and strawberry (Fragaria × ananassa) were used as specimens to clarify the effect of the discharge treatment on edible parts of the plants. The specimens were cultivated in pots filled with artificial soil, which included chicken manure charcoal. Distilled water was sprayed on the artificial soil and drained through a hole in the pots to a water storage tank. The water was circulated from the water storage tank to the cultivation pots after 15 or 30 min discharge treatment on alternate days. A magnetic compression-type pulsed power generator was used to produce the bubble discharge with a repetition rate of 250 pps. The plant height in the growth phase and the dry weight of the harvested plants were improved markedly by the discharge treatment in water. The soil and plant analyzer development (SPAD) value of the plants also improved in the growth phase of the plants. The concentration of nitrate nitrogen, which mainly contributed to the improvement of the growth rate, in the water increased with the discharge treatment. The Brix value of edible parts of Fragaria × ananassa increased with the discharge treatment. The inactivation of bacteria in the water was also confirmed with the discharge treatment.

  17. Size-Dependent Growth Rate of Nitzschia closteriumat Different Concentrations of Petroleum Hydrocarbon

    Institute of Scientific and Technical Information of China (English)

    YANG Rujun; TANG Hongjie; XIN Yu; WANG Xiulin

    2009-01-01

    The maximum growth rate of Nitzschia closterium at various concentrations of petroleum hydrocarbon was studied. The influence of petroleum hydrocarbon on cell stze as a function of concentration was discussed. The relationship between maximum growth rate of Nitzschia closterium and cell median equivalent spherical diameter (MESD) was also carefully studied. The experi-mental results showed that the growth rate of Nitzschia closterium was generally suppressed by petroleum hydrocarbon, which had greater effects at both low and high concentrations than at intermediate concentrations. No significant changes in cell size distribu-tion were observed during the growth penod of Nitzschia closterium.The Gaussian function could give a clear description of the cell size distribution of Nitzschia closterium, and the MESD value ranged from 2.71 to 6.82/am. The MESD decreased when the cell was exposed to petroleum hydrocarbon, and the reduction of cell MESD was much more significant at both relatively high and low hy-drocarbon concentrations. The presence of petroleum hydrocarbon changed the relationship between umax and MESD from an al-lometric function to a U-shaped curve. When the MESD was below 5.07 um, umax decreased along with increased MESD, whereas when MESD was above 5.07 um, umax increased along wtth MESD, which deviated from the allometric model.

  18. Enhancement of the Initial Growth Rate of Agricultural Plants by Using Static Magnetic Fields.

    Science.gov (United States)

    Kim, Seung C; Mason, Alex; Im, Wooseok

    2016-01-01

    Electronic devices and high-voltage wires induce magnetic fields. A magnetic field of 1,300-2,500 Gauss (0.2 Tesla) was applied to Petri dishes containing seeds of Garden Balsam (Impatiens balsamina), Mizuna (Brassica rapa var. japonica), Komatsuna (Brassica rapa var. perviridis), and Mescluns (Lepidium sativum). We applied magnets under the culture dish. During the 4 days of application, we observed that the stem and root length increased. The group subjected to magnetic field treatment (n = 10) showed a 1.4 times faster rate of growth compared with the control group (n = 11) in a total of 8 days (p <0.0005). This rate is 20% higher than that reported in previous studies. The tubulin complex lines did not have connecting points, but connecting points occur upon the application of magnets. This shows complete difference from the control, which means abnormal arrangements. However, the exact cause remains unclear. These results of growth enhancement of applying magnets suggest that it is possible to enhance the growth rate, increase productivity, or control the speed of germination of plants by applying static magnetic fields. Also, magnetic fields can cause physiological changes in plant cells and can induce growth. Therefore, stimulation with a magnetic field can have possible effects that are similar to those of chemical fertilizers, which means that the use of fertilizers can be avoided. PMID:27500712

  19. High Temperature Fatigue Crack Growth Rate of G91 Steel with Applying 30 Seconds Hold Time

    International Nuclear Information System (INIS)

    Subsection NH since 2004. The database of creep and creep-fatigue crack growth rate of G91 steel is necessary for the structural integrity evaluation of the SFR structures because the database of these properties of materials is insufficient through the world. Moreover, it is difficult to use the database which is gained by the research center of advanced countries because it is not to be opened. Therefore, it is necessary to make an effort to get the database of material properties. Creep-fatigue crack initiation and growth tests for a G91 tubular specimen, including a machined defect, have been performed by Kim and it attempted to assess a high temperature crack behavior of G91 side plate specimen by Lee. Creep-fatigue crack growth rate were compared in terms of different temperature range. Tests were performed at temperatures of 500, 550 and 600, respectively. Stress ratio was set to 0.1 and trapezoidal shape of stress condition was applied to the specimens to perform the creep-fatigue crack growth rate tests. Each specimen's surface was polished and fatigue pre-crack was manufactured by fatigue test before the high temperature test. And DCPD method was adopted to measure the crack length in the high temperature

  20. Volume Changes After Stereotactic LINAC Radiotherapy in Vestibular Schwannoma: Control Rate and Growth Patterns

    Energy Technology Data Exchange (ETDEWEB)

    Langenberg, Rick van de, E-mail: rickvandelangenberg@hotmail.com [Department of Otolaryngology, Head and Neck Surgery, Maastricht University Medical Centre (Netherlands); Dohmen, Amy J.C. [Department of Otolaryngology, Head and Neck Surgery, Maastricht University Medical Centre (Netherlands); Bondt, Bert J. de [Department of Radiology, Isala klinieken Zwolle (Netherlands); Nelemans, Patty J. [Department of Epidemiology and Statistics, Maastricht University (Netherlands); Baumert, Brigitta G. [Department of Maastricht Radiation Oncology (MAASTRO), GROW (School for Oncology and Developmental Biology), Maastricht University Medical Center (Netherlands); Stokroos, Robert J. [Department of Otolaryngology, Head and Neck Surgery, Maastricht University Medical Centre (Netherlands)

    2012-10-01

    Purpose: The purpose of this study was to evaluate the control rate of vestibular schwannomas (VS) after treatment with linear accelerator (LINAC)-based stereotactic radiosurgery (SRS) or radiotherapy (SRT) by using a validated volumetric measuring tool. Volume-based studies on prognosis after LINAC-based SRS or SRT for VS are reported scarcely. In addition, growth patterns and risk factors predicting treatment failure were analyzed. Materials and Methods: Retrospectively, 37 VS patients treated with LINAC based SRS or SRT were analyzed. Baseline and follow-up magnetic resonance imaging scans were analyzed with volume measurements on contrast enhanced T1-weighted magnetic resonance imaging. Absence of intervention after radiotherapy was defined as 'no additional intervention group, ' absence of radiological growth was defined as 'radiological control group. ' Significant growth was defined as a volume change of 19.7% or more, as calculated in a previous study. Results: The cumulative 4-year probability of no additional intervention was 96.4% {+-} 0.03; the 4-year radiological control probability was 85.4% {+-} 0.1). The median follow-up was 40 months. Overall, shrinkage was seen in 65%, stable VS in 22%, and growth in 13%. In 54% of all patients, transient swelling was observed. No prognostic factors were found regarding VS growth. Previous treatment and SRS were associated with transient swelling significantly. Conclusions: Good control rates are reported for LINAC based SRS or SRT in VS, in which the lower rate of radiological growth control is attributed to the use of the more sensitive volume measurements. Transient swelling after radiosurgery is a common phenomenon and should not be mistaken for treatment failure. Previous treatment and SRS were significantly associated with transient swelling.

  1. Impacts of warming revealed by linking resource growth rates with consumer functional responses.

    Science.gov (United States)

    West, Derek C; Post, David M

    2016-05-01

    Warming global temperatures are driving changes in species distributions, growth and timing, but much uncertainty remains regarding how climate change will alter species interactions. Consumer-Resource interactions in particular can be strongly impacted by changes to the relative performance of interacting species. While consumers generally gain an advantage over their resources with increasing temperatures, nonlinearities can change this relation near temperature extremes. We use an experimental approach to determine how temperature changes between 5 and 30 °C will alter the growth of the algae Scenedesmus obliquus and the functional responses of the small-bodied Daphnia ambigua and the larger Daphnia pulicaria. The impact of warming generally followed expectations, making both Daphnia species more effective grazers, with the increase in feeding rates outpacing the increases in algal growth rate. At the extremes of our temperature range, however, warming resulted in a decrease in Daphnia grazing effectiveness. Between 25 and 30 °C, both species of Daphnia experienced a precipitous drop in feeding rates, while algal growth rates remained high, increasing the likelihood of algal blooms in warming summer temperatures. Daphnia pulicaria performed significantly better at cold temperatures than D. ambigua, but by 20 °C, there was no significant difference between the two species, and at 25 °C, D. ambigua outperformed D. pulicaria. Warming summer temperatures will favour the smaller D. ambigua, but only over a narrow temperature range, and warming beyond 25 °C could open D. ambigua to invasion from tropical species. By fitting our results to temperature-dependent functions, we develop a temperature- and density-dependent model, which produces a metric of grazing effectiveness, quantifying the grazer density necessary to halt algal growth. This approach should prove useful for tracking the transient dynamics of other density-dependent consumer

  2. Cellular processing of 125I- and 111in-labeled epidermal growth factor (EGF) bound to cultured A431 tumor cells

    International Nuclear Information System (INIS)

    Low molecular weight of epidermal growth factor (EGF) enables better intratumoral penetration in comparison with larger targeting proteins, but the cellular retention of EGF-associated radioactivity is poor for directly iodinated EGF. An attempt was made to improve intracellular retention by the use of metal-diethylenetriaminepentaacetic acid or nonphenolic linker (N-succinimidyl-para-iodobenzoate) as labeling agents. The use of nonphenolic linker did not improve retention of the radioactivity in A431 carcinoma cell line. The use of the radiometal label provided an appreciable prolongation of radioactivity residence inside the cell

  3. Physiological levels of nitrate support anoxic growth by denitrification of Pseudomonas aeruginosa at growth rates reported in cystic fibrosis lungs and sputum

    DEFF Research Database (Denmark)

    Klitten, Laura Line; Alhede, Morten; Kolpen, Mette;

    2014-01-01

    reported that O2 is mainly consumed by the activated PMNs, while O2 consumption by aerobic respiration is diminutive and nitrous oxide (N2O) is produced in infected CF sputum. This suggests that the reported growth rates of P. aeruginosa in lungs and sputum may result from anaerobic respiration using...... denitrification. The growth rate of P. aeruginosa achieved by denitrification at physiological levels (~400 μM) of nitrate (NO(-) 3) is however, not known. Therefore, we have measured growth rates of anoxic cultures of PAO1 and clinical isolates (n = 12) in LB media supplemented with NO(-) 3 and found a...... significant increase of growth when supplementing PAO1 and clinical isolates with ≥150 μM NO(-) 3 and 100 μM NO(-) 3, respectively. An essential contribution to growth by denitrification was demonstrated by the inability to establish a significantly increased growth rate by a denitrification deficient Δnir...

  4. Economic Growth, Exchange Rate and Constrained Competiveness of the Tourism Sector in Andalucía

    Directory of Open Access Journals (Sweden)

    Nasir Muhammad Ali

    2015-12-01

    Full Text Available This paper examines the relationship between tourism and economic growth, analyzing key factors affecting tourism income in Andalucía, Spain. Based on time series annual data for the period 2005 to 2012 and a multiple regression analysis we show that international tourism has made an important contribution to Andalucía’s economic growth. Some of the factors considered in the analysis include the number of luxury hotels, the hotel price index and the exchange rate, though the latter is outside of the control of local authorities under the European Monetary Union (EMU.

  5. FACTORS AFFECTING FATIGUE CRACK GROWTH RATES OF FIBER REINFORCED METAL LAMINATES

    Institute of Scientific and Technical Information of China (English)

    1998-01-01

    Based upon an analytical model for predicting the crack growth in fiber reinforced metal laminates (FRMLs), some factors affecting the fatigue crack growth rates of FRMLs were analyzed, including the lay-up of FRMLs, the modulus of the fibers, the residual stresses in FRMLs, the bonding strength and the shear modulus of the adhesive, etc.It was shown from the present analysis that the interface number of the laminates, the modulus of the fibers and the residual stresses in FRMLs have very great effects on the fatigue lives of FRMLs, but the effects of the bonding strength and the shear modulus of the adhesive are relatively small.

  6. Growth rates of rhizosphere microorganisms depend on competitive abilities of plants for nitrogen

    Science.gov (United States)

    Blagodatskaya, Evgenia; Littschwager, Johanna; Lauerer, Marianna; Kuzyakov, Yakov

    2010-05-01

    Rhizosphere - one of the most important ‘hot spots' in soil - is characterized not only by accelerated turnover of microbial biomass and nutrients but also by strong intra- and inter-specific competition. Intra-specific competition occurs between individual plants of the same species, while inter-specific competition can occur both at population level (plant species-specific, microbial species-specific interactions) and at community level (plant - microbial interactions). Such plant - microbial interactions are mainly governed by competition for available N sources, since N is one of the main growth limiting nutrients in natural ecosystems. Functional structure and activity of microbial community in rhizosphere is not uniform and is dependent on quantity and quality of root exudates which are plant specific. It is still unclear how microbial growth and turnover in the rhizosphere are dependent on the features and competitive abilities of plants for N. Depending on C and N availability, acceleration and even retardation of microbial activity and carbon mineralization can be expected in the rhizosphere of plants with high competitive abilities for N. We hypothesized slower microbial growth rates in the rhizosphere of plants with smaller roots, as they usually produce less exudates compared to plants with small shoot-to-root ratio. As the first hypothesis is based solely on C availability, we also expected the greater effect of N availability on microbial growth in rhizosphere of plants with smaller root mass. These hypothesis were tested for two plant species of strawberry: Fragaria vesca L. (native species), and Duchesnea indica (Andrews) Focke (an invasive plant in central Europe) growing in intraspecific and interspecific competition. Microbial biomass and the kinetic parameters of microbial growth in the rhizosphere were estimated by dynamics of CO2 emission from the soil amended with glucose and nutrients. Specific growth rate (µ) of soil microorganisms was

  7. Bivalve growth rate and isotopic variability across the Barents Sea Polar Front

    Science.gov (United States)

    Carroll, Michael L.; Ambrose, William G.; Locke V, William L.; Ryan, Stuart K.; Johnson, Beverly J.

    2014-02-01

    Analysis of bivalve shell increments provides a means to reconstruct long-term patterns in growth histories and assess factors that regulate marine ecosystems, while tissue stable isotopes are indicators of food sources and trophic dynamics. We examined shell growth patterns and tissue stable isotopic composition (δ13C and δ15N) of the hairy cockle (Ciliatocardium ciliatum) in the northwest Barents Sea to evaluate the influence of different water masses and the Polar Front on growth rates and food sources and to assess the influence of climatic variability on ecological processes over seasonal to decadal scales. Shell growth rates were highest in Atlantic water, intermediate in Arctic water, and lowest at the Polar Front. Temporal patterns of ontogenetically-adjusted growth (SGI) were negatively correlated with the Atlantic Multidecadal Oscillation (AMO), local precipitation and ice-free days. The highest growth occurred during colder periods with more sea ice, while lower growth was associated with warmer periods and less sea ice. Stable isotope values of lipid-extracted tissues from Atlantic water cockles were enriched in δ13C by up to 2.1‰ and δ15N by 1.5‰ compared to animals from Arctic waters. Distinct seasonal and water mass variations in stable isotopic values reflect spatial and temporal variability in food supplies to the bivalves in this region on small spatial scales. Overall, Atlantic waters supported the highest growth rates, the most complex trophic webs, and the greatest sensitivity to interannual variability in environmental conditions. Bivalves from Arctic waters were the most distinct of the three groups in their response to regional climate forcing and local environmental manifestations of those conditions. The Polar Front exhibits growth and isotopic characteristics predominantly of the Atlantic domain. These results demonstrate that integrating results of sclerochronological and stable isotopic analyses of benthic bivalves provide

  8. Cristal size distribution in metamorphic rocks: an example for the relationship between nucleation and growth rates with overstepping

    International Nuclear Information System (INIS)

    Crystal size distribution in metamorphic rocks provide fundamental information about crystal nucleation and growth rate, growth time and the degree of overstepping. Crystal size distribution data for garnet, saluretil, keynote, and and alusite crystals from the aureole demonstrate that the earliest formed of this minerals, garnet, has the highest population density and the shortest growth time. The last formed mineral, and alusite, has the lowest population density and longest growth time. keynote and saluretil have the similar population density and growth times intermediate between those of overstepping on the nucleation and growth rates of minerals during metamorphism

  9. Postnatal growth rates covary weakly with embryonic development rates and do not explain adult mortality probability among songbirds on four continents

    Science.gov (United States)

    Martin, Thomas E.; Oteyza, Juan C.; Mitchell, Adam E.; Potticary, Ahva L.; Lloyd, P.

    2016-01-01

    Growth and development rates may result from genetic programming of intrinsic processes that yield correlated rates between life stages. These intrinsic rates are thought to affect adult mortality probability and longevity. However, if proximate extrinsic factors (e.g., temperature, food) influence development rates differently between stages and yield low covariance between stages, then development rates may not explain adult mortality probability. We examined these issues based on study of 90 songbird species on four continents to capture the diverse life-history strategies observed across geographic space. The length of the embryonic period explained little variation (ca. 13%) in nestling periods and growth rates among species. This low covariance suggests that the relative importance of intrinsic and extrinsic influences on growth and development rates differs between stages. Consequently, nestling period durations and nestling growth rates were not related to annual adult mortality probability among diverse songbird species within or among sites. The absence of a clear effect of faster growth on adult mortality when examined in an evolutionary framework across species may indicate that species that evolve faster growth also evolve physiological mechanisms for ameliorating costs on adult mortality. Instead, adult mortality rates of species in the wild may be determined more strongly by extrinsic environmental causes.

  10. Growth rates, reproductive phenology, and pollination ecology of Espeletia grandiflora (Asteraceae), a giant Andean caulescent rosette.

    Science.gov (United States)

    Fagua, J C; Gonzalez, V H

    2007-01-01

    From March 2001 to December 2002, we studied the reproductive phenology, pollination ecology, and growth rates of Espeletia grandiflora Humb. and Bonpl. (Asteraceae), a giant caulescent rosette from the Páramos of the Eastern Andes of Colombia. Espeletia grandiflora was found to be predominantly allogamous and strongly self-incompatible. Bumblebees (Bombus rubicundus and B. funebris) were the major pollinators of E. grandiflora, although moths, hummingbirds, flies, and beetles also visited flowers. Inflorescence development began in March and continued through August to September. Plants flowered for 30 - 96 days with a peak from the beginning of October through November. The percentage of flowering plants strongly differed among size classes and between both years. Seed dispersal occurred as early as September through May of the following year. The average absolute growth rate for juveniles and adults rate was 7.6 cm/year. Given the scarcity of floral visitors at high altitudes due to climatic conditions, we suggest that even small contributions from a wide range of pollinators might be advantageous for pollination of E. grandiflora. Long-term studies on different populations of E. grandiflora are required to determine if the high growth rates are representative, to quantify the variation in the flowering behavior within and among populations, and to establish if nocturnal pollination is a trait that is exclusive to our population of E. grandiflora. PMID:17066366

  11. Biomedical Progress Rates as New Parameters for Models of Economic Growth in Developed Countries

    Directory of Open Access Journals (Sweden)

    Alex Zhavoronkov

    2013-11-01

    Full Text Available While the doubling of life expectancy in developed countries during the 20th century can be attributed mostly to decreases in child mortality, the trillions of dollars spent on biomedical research by governments, foundations and corporations over the past sixty years are also yielding longevity dividends in both working and retired population. Biomedical progress will likely increase the healthy productive lifespan and the number of years of government support in the old age. In this paper we introduce several new parameters that can be applied to established models of economic growth: the biomedical progress rate, the rate of clinical adoption and the rate of change in retirement age. The biomedical progress rate is comprised of the rejuvenation rate (extending the productive lifespan and the non-rejuvenating rate (extending the lifespan beyond the age at which the net contribution to the economy becomes negative. While staying within the neoclassical economics framework and extending the overlapping generations (OLG growth model and assumptions from the life cycle theory of saving behavior, we provide an example of the relations between these new parameters in the context of demographics, labor, households and the firm.

  12. Structural Growth Trajectories and Rates of Change in the First 3 Months of Infant Brain Development

    Science.gov (United States)

    Holland, Dominic; Chang, Linda; Ernst, Thomas M.; Curran, Megan; Buchthal, Steven D.; Alicata, Daniel; Skranes, Jon; Johansen, Heather; Hernandez, Antonette; Yamakawa, Robyn; Kuperman, Joshua M.; Dale, Anders M.

    2016-01-01

    IMPORTANCE The very early postnatal period witnesses extraordinary rates of growth, but structural brain development in this period has largely not been explored longitudinally. Such assessment may be key in detecting and treating the earliest signs of neurodevelopmental disorders. OBJECTIVE To assess structural growth trajectories and rates of change in the whole brain and regions of interest in infants during the first 3 months after birth. DESIGN, SETTING, AND PARTICIPANTS Serial structural T1-weighted and/or T2-weighted magnetic resonance images were obtained for 211 time points from 87 healthy term-born or term-equivalent preterm-born infants, aged 2 to 90 days, between October 5, 2007, and June 12, 2013. MAIN OUTCOMES AND MEASURES We segmented whole-brain and multiple subcortical regions of interest using a novel application of Bayesian-based methods. We modeled growth and rate of growth trajectories nonparametrically and assessed left-right asymmetries and sexual dimorphisms. RESULTS Whole-brain volume at birth was approximately one-third of healthy elderly brain volume, and did not differ significantly between male and female infants (347 388 mm3 and 335 509 mm3, respectively, P = .12). The growth rate was approximately 1%/d, slowing to 0.4%/d by the end of the first 3 months, when the brain reached just more than half of elderly adult brain volume. Overall growth in the first 90 days was 64%. There was a significant age-by-sex effect leading to widening separation in brain sizes with age between male and female infants (with male infants growing faster than females by 200.4 mm3/d, SE = 67.2, P = .003). Longer gestation was associated with larger brain size (2215 mm3/d, SE = 284, P = 4×10−13). The expected brain size of an infant born one week earlier than average was 5% smaller than average; at 90 days it will not have caught up, being 2% smaller than average. The cerebellum grew at the highest rate, more than doubling in 90 days, and the hippocampus

  13. Iron and Multivitamin Supplements in Children and its Association with Growth rate

    Directory of Open Access Journals (Sweden)

    M Saeidi

    2014-04-01

    Full Text Available Introduction: Vitamin deficiency and iron deficiency anemia are common nutritional problems, at least in children under 5. These materials shortage, especially in the first two years of life, impair physical and brain growth, reduces the child's learning ability, reduces body resistance against infections, behavioral changes, apathy and finally social and economic adverse consequences would be followed. This study aimed to determine the supplements used in children under two years and its Association with Growth rate in Mashhad City.   Materials and Methods: In this cross-sectional descriptive study, 300 children 6 to 24 months were recruited in health centers in Mashhad, Data was collected from mother and and children’ records and valid and reliable  questionnaire was used to collect data. The data was analyzed by statistical tests and SPSS 11.5 and P  Results: Results showed that 13.7 percent of families were with low income, 82.7 percent middle income and 3.7 percent well income. In growth chart, 86.7 percent of children showed appropriate growth, 10.3 percent had delayed growth and 3 percent had horizontal growth curve .In 80.7 percent of families, maternal multivitamin and iron drops have been used to their children regularly, 1.7 percent did not believe in these supplements and 17.7 percent of mothers sometimes used these supplements for their children. Results also showed statistical correlation significant variables of parental education, family income, mothers referred to health centers for monitoring the growth and get face to face training of personnel center drops of multivitamin with iron and growth status of children variable is available, so children who regularly have used supplements and income level and above are literate parents have grown more favorable than the other kids (P

  14. Iron and Multivitamin Supplements in Children and its Association with Growth rate

    Directory of Open Access Journals (Sweden)

    Masumeh Saeidi

    2013-12-01

    Full Text Available Introduction: Vitamin deficiency and iron deficiency anemia are common nutritional problems, at least in children under 5. These materials shortage, especially in the first two years of life, impair physical and brain growth, reduces the child's learning ability, reduces body resistance against infections, behavioral changes, apathy and finally social and economic adverse consequences would be followed. This study aimed to determine the supplements used in children under two years and its Association with Growth rate in Mashhad City.   Materials and Methods: In this cross-sectional descriptive study , 300 children 6 to 24 months were recruited in health centers in Mashhad, Data was collected from mother and and children’ records and valid and reliable  questionnaire was used to collect data. The data was analyzed by statistical tests and SPSS 11.5 and P  Results: Results showed that 13.7 percent of families were with low income, 82.7 percent middle income and 3.7 percent well income. In growth chart, 86.7 percent of children showed appropriate growth, 10.3 percent had delayed growth and 3 percent had horizontal growth curve .In 80.7 percent of families, maternal multivitamin and iron drops have been used to their children regularly, 1.7 percent did not believe in these supplements and 17.7 percent of mothers sometimes used these supplements for their children. Results also showed statistical correlation significant variables of parental education, family income, mothers referred to health centers for monitoring the growth and get face to face training of personnel center drops of multivitamin with iron and growth status of children variable is available, so children who regularly have used supplements and income level and above are literate parents have grown more favorable than the other kids (P

  15. Effect of cold work on the growth rates of stress corrosion cracks in structural materials of nuclear systems

    International Nuclear Information System (INIS)

    The growth rates of stress corrosion cracks in austenitic stainless steels and nickel base alloy 600 exposed to simulated boiling water reactor coolant were measured by fracture mechanics testing techniques. Cold work may increase the crack growth rates up to one hundred times. In both, the annealed condition and the cold worked condition, the stress corrosion crack growth rates are independent of stress intensity over a wide K-range and crack growth rates correlate well with yield strength and hardness. In the annealed condition the fracture path is intergranular, but higher degrees of cold work introduce higher proportions of transgranular stress corrosion cracking

  16. The importance of actual tumor growth rate on disease free survival and overall survival in laryngeal squamous cell carcinoma

    International Nuclear Information System (INIS)

    Background and purpose: Evaluation of the variation in tumor growth rate and the influence of tumor growth rate on disease free survival (DFS) and overall survival (OS) in laryngeal squamous cell carcinoma (LSCC). Material and methods: We delineated tumor volume on a diagnostic and planning CT scan in 131 patients with laryngeal squamous cell carcinoma and calculated the tumor growth rate. Primary endpoint was DFS. Follow up data were collected retrospectively. Results: A large variation in tumor growth rate was seen. When dichotomized with a cut-off point of −0.3 ln(cc/day), we found a significant association between high growth rate and worse DFS (p = 0.008) and OS (p = 0.013). After stepwise adjustment for potential confounders (age, differentiation and tumor volume) this significant association persisted. However, after adjustment of N-stage association disappeared. Exploratory analyses suggested a strong association between N-stage and tumor growth rate. Conclusions: In laryngeal squamous cell carcinoma, there is a large variation in tumor growth rate. This tumor growth rate seems to be an important factor in disease free survival and OS. This tumor growth rate is independent of age, differentiation and tumor volume associated with DFS, but N-stage seems to be a more important risk factor

  17. Estimating the division rate of the growth-fragmentation equation with a self-similar kernel

    International Nuclear Information System (INIS)

    We consider the growth-fragmentation equation and we address the problem of estimating the division rate from the stable size distribution of the population, which is easily measured, but non-smooth. We propose a method based on the Mellin transform for growth-fragmentation equations with self-similar kernels. We build a sequence of functions which converges to the density of the population in division, simultaneously in several weighted L2 spaces, as the measurement error goes to 0. This improves the previous results for self-similar kernels and allows us to understand the partial results for general fragmentation kernels. Numerical simulations confirm the theoretical results. Moreover, our numerical method is tested on real biological data, arising from a bacteria growth and fission experiment. (paper)

  18. Automatic Evaluation of Colonies Growth rate of Yeasts incubated in Petri dishes using Mobile Platform

    Directory of Open Access Journals (Sweden)

    Alecsander Pereira Martins

    2015-10-01

    Full Text Available This paper proposes an automatic method based on computer vision implemented in mobile platform capable of monitoring the growth of microbial colonies incubated in Petri dishes. The developed optimized image processing algorithm performs this task without human intervention from images of colonies of the microorganism in different evolution phases. The contribution of this paper is the development of a fast and robust mobile tool to assist bioprocess experts in monitoring the growth of colonies without using the conventional error prone evaluation techniques. The obtained results successfully demonstrated dimensional alterations in colonies in a faster and more precise fashion when compared with the conventional method, with the additional advantage of versatility in producing reliable estimation of the growth rates with higher statistical significance.

  19. Adult survival and population growth rate in Colorado big brown bats (Eptesicus fuscus)

    Science.gov (United States)

    O'Shea, T.J.; Ellison, L.E.; Stanley, T.R.

    2011-01-01

    We studied adult survival and population growth at multiple maternity colonies of big brown bats (Eptesicus fuscus) in Fort Collins, Colorado. We investigated hypotheses about survival using information-theoretic methods and mark-recapture analyses based on passive detection of adult females tagged with passive integrated transponders. We constructed a 3-stage life-history matrix model to estimate population growth rate (??) and assessed the relative importance of adult survival and other life-history parameters to population growth through elasticity and sensitivity analysis. Annual adult survival at 5 maternity colonies monitored from 2001 to 2005 was estimated at 0.79 (95% confidence interval [95% CI] = 0.77-0.82). Adult survival varied by year and roost, with low survival during an extreme drought year, a finding with negative implications for bat populations because of the likelihood of increasing drought in western North America due to global climate change. Adult survival during winter was higher than in summer, and mean life expectancies calculated from survival estimates were lower than maximum longevity records. We modeled adult survival with recruitment parameter estimates from the same population. The study population was growing (?? = 1.096; 95% CI = 1.057-1.135). Adult survival was the most important demographic parameter for population growth. Growth clearly had the highest elasticity to adult survival, followed by juvenile survival and adult fecundity (approximately equivalent in rank). Elasticity was lowest for fecundity of yearlings. The relative importances of the various life-history parameters for population growth rate are similar to those of large mammals. ?? 2011 American Society of Mammalogists.

  20. Speed over efficiency: locusts select body temperatures that favour growth rate over efficient nutrient utilization

    DEFF Research Database (Denmark)

    Miller, Gabriel A; Clissold, Fiona J; Mayntz, David;

    2009-01-01

    Ectotherms have evolved preferences for particular body temperatures, but the nutritional and life-history consequences of such temperature preferences are not well understood. We measured thermal preferences in Locusta migratoria (migratory locusts) and used a multi-factorial experimental design...... diets or a choice between both. Locusts placed in a thermal gradient selected temperatures near 38°C, maximizing rates of weight gain; however, this enhanced growth rate came at the cost of poor protein and carbohydrate utilization. Protein and carbohydrate were equally digested across temperature...... to investigate relationships between growth/development and macronutrient utilization (conversion of ingesta to body mass) as a function of temperature. A range of macronutrient intake values for insects at 26, 32 and 38°C was achieved by offering individuals high-protein diets, high-carbohydrate...

  1. TEST OF THE CATCH-UP HYPOTHESIS IN AFRICAN AGRICULTURAL GROWTH RATES

    Directory of Open Access Journals (Sweden)

    Kalu Ukpai IFEGWU

    2015-11-01

    Full Text Available The paper tested the catch-up hypothesis in agricultural growth rates of twenty-six African countries. Panel data used was drawn from the Food and Agricultural Organization Statistics (FAOSTAT of the United Nations. The Data Envelopment Analysis Method for measuring productivity was used to estimate productivity growth rates. The cross-section framework consisting of sigma-convergence and beta-convergence was employed to test the catching up process. Catching up is said to exist if the value of beta is negative and significant. Since catching up does not necessarily imply narrowing of national productivity inequalities, sigma-convergence which measures inequality, was estimated for the same variables. The results showed evidence of the catch-up process, but failed to find a narrowing of productivity inequalities among countries.

  2. Fatigue crack growth rate studies of medium sulfur low allow steels tested in high temperature water

    International Nuclear Information System (INIS)

    Fatigue crack propagation tests of medium sulfur (0.007 to 0.011 wt%) ASTM A508-Class 2 forgings were performed in deaerated high purity, high temperature water. In general, these forgings did not exhibit environmentally assisted cracking (EAC) in tests at 149 degrees C (300 degrees F) or at 260 degrees C (500 degrees F). Lowering the pH did not raise the crack growth rates significantly. However, adding a small amount of oxygenated water to the feedwater increased the fatigue crack growth rates (FCGR) by a factor of about 4. Automated analysis of the sulfide inclusions in polished sections of the forgings supported a previously proposed relationship for susceptibility to EAC

  3. A study on Haemophilus influenzae type b growth rate and capsule production in different media

    Directory of Open Access Journals (Sweden)

    Afshar, M.

    2012-06-01

    Full Text Available to compare growth rate and capsule production. Four liquid media namely brain heart infusion broth (BHI, trypticase soy broth (TSB, Mueller Hinton Broth (MHB and Gonococci broth (GC with added supplements (1% hemoglobin, 1% Isovitalex were used. The growth was measured by colony counting (CFU/ml using serial dilution. Four of the isolates showed the highest growth rate with the average of 1013 CFU/ml on BHI broth while TSB had the second highest growth of more than 1010 CFU/ml in an 18-hour culture at 37 ºC culture. In the next step, the amount of capsular polysaccharide (CPS-b antigen which is made of Polyribosyl ribitol phosphate (PRP was assessed all isolates by two methods: modified Indirect Sandwich Enzyme-linked immunosorbent assay (ELISA and Bial method to select the isolate producing the highest amount of PRP. The antisera used in sandwich ELISA were prepared by immunization of Rabbit and Rat. The maximal amount of PRP was produced by isolate Hib (5s with the amount of 321 mg/lit.

  4. Status and trend of tree growth and mortality rate at the CONECOFOR plots, 1997-2004

    Directory of Open Access Journals (Sweden)

    Gianfranco Fabbio

    2013-11-01

    Full Text Available The circumference of trees in the CONECOFOR permanent monitoring plots (PMPs were measured by three surveys carried out in 1997, 2000 and 2005. Plots were arranged into forest types according to tree species, management system and stand structure: beech (Fagus sylvatica L. and spruce (Picea abies K. high forests, aged coppice forests and transitory crops (deciduous, evergreen oaks and beech. Diameter distribution, basal area, basal area increment, tree mortality rate and in-growth were calculated per layer (dominant, intermediate, dominated within each PMP, to point out relative contributions and changes. A range in relative annual growth was detected both within and between types over the monitored period, but an obvious reduction of annual increment was found in two/thirds of plots over 2000-04 as compared to 1997-99. Current mortality, mostly allocated into the dominated and intermediate layers, can be explained as “regular” due to overstocking and high inter-tree competition in almost all of the observed case-studies. Opposite patterns were found to occur as for stand growth vs. mortality rate between coppice forests and the other types owing to the different dynamics of tree competition in progress. Drought 2003 is the likely large-scale factor determining the reduced annual growth course over the second period.

  5. Scaling of the growth rate of magnetic islands in the heliosheath

    CERN Document Server

    Schoeffler, K M; Swisdak, M

    2012-01-01

    Current sheets thinner than the ion inertial length are unstable to the tearing instability and will develop magnetic islands that grow due to magnetic reconnection. We investigate whether the growth of magnetic islands in a current sheet can continue indefinitely, or in the case of the heliosheath until reaching a neighboring current sheet, and at what rate the islands grow. We investigate the development and growth of magnetic islands using a particle-in-cell code, starting from particle noise. Performing a scaling of the growth of magnetic islands versus the system size, we find that the growth rate is independent of the system size up to the largest simulation we were able to complete. The islands are able to continue growing as long as they merge with each other and maintain a high aspect ratio. Otherwise there is not enough magnetic tension to sustain reconnection. When applied to the sectored magnetic fields in the heliosheath, we show that the islands can continue growing until they reach the sector w...

  6. Using time-dependent models to investigate body condition and growth rate of the giant gartersnake

    Science.gov (United States)

    Coates, P.S.; Wylie, G.D.; Halstead, B.J.; Casazza, M.L.

    2009-01-01

    Identifying links between phenotypic attributes and fitness is a primary goal of reproductive ecology. Differences in within-year patterns of body condition between sexes of gartersnakes in relation to reproduction and growth are not fully understood. We conducted an 11-year field study of body condition and growth rate of the giant gartersnake Thamnophis gigas across 13 study areas in the Central Valley of California, USA. We developed a priori mixed effects models of body condition index (BCI), which included covariates of time, sex and snout-vent length and reported the best-approximating models using an information theoretic approach. Also, we developed models of growth rate index (GRI) using covariates of sex and periods based on reproductive behavior. The largest difference in BCI between sexes, as predicted by a non-linear (cubic) time model, occurred during the mating period when female body condition (0.014??0.001 se) was substantially greater than males (-0.027??0.002 se). Males likely allocated energy to search for mates, while females likely stored energy for embryonic development. We also provided evidence that males use more body energy reserves than females during hibernation, perhaps because of different body temperatures between sexes. We found GRI of male snakes was substantially lower during the mating period than during a non-mating period, which indicated that a trade-off existed between searching for mates and growth. These findings contribute to our understanding of snake ecology in a Mediterranean climate. ?? 2009 The Zoological Society of London.

  7. SIMULATION OF FIRE DYNAMICS WITH VARIOUS GROWTH RATE IN PREMISES WITH NATURAL VENTILATION

    OpenAIRE

    V. V. Nevdakh

    2015-01-01

    Computer simulation of the initial fire stage dynamics with various growth rate have been carried out with the help of FDS software. In case of a quick fire 1055 kW heat liberation has been reached in accordance with quadratic law within 100 seconds, averagely within 250 seconds and within 500 seconds when the fire rate is slow. Source of fire has been located on the floor and at the height of 2 m. A doorway of 0.8×2.0 m size and two 0.8×0.1 m openings have been used as ventilation holes. One...

  8. Rate-Independent Processes with Linear Growth Energies and Time-Dependent Boundary Conditions

    Czech Academy of Sciences Publication Activity Database

    Kružík, Martin; Zimmer, J.

    2012-01-01

    Roč. 5, č. 3 (2012), s. 591-604. ISSN 1937-1632 R&D Projects: GA AV ČR IAA100750802 Grant ostatní: GA ČR(CZ) GAP201/10/0357 Institutional research plan: CEZ:AV0Z10750506 Keywords : concentrations * oscillations * time-dependent boundary conditions * rate-independent evolution Subject RIV: BA - General Mathematics http://library.utia.cas.cz/separaty/2011/MTR/kruzik-rate-independent processes with linear growth energies and time-dependent boundary conditions.pdf

  9. A systems biology approach uncovers cellular strategies used by Methylobacterium extorquens AM1 during the switch from multi- to single-carbon growth.

    Directory of Open Access Journals (Sweden)

    Elizabeth Skovran

    Full Text Available BACKGROUND: When organisms experience environmental change, how does their metabolic network reset and adapt to the new condition? Methylobacterium extorquens is a bacterium capable of growth on both multi- and single-carbon compounds. These different modes of growth utilize dramatically different central metabolic pathways with limited pathway overlap. METHODOLOGY/PRINCIPAL FINDINGS: This study focused on the mechanisms of metabolic adaptation occurring during the transition from succinate growth (predicted to be energy-limited to methanol growth (predicted to be reducing-power-limited, analyzing changes in carbon flux, gene expression, metabolites and enzymatic activities over time. Initially, cells experienced metabolic imbalance with excretion of metabolites, changes in nucleotide levels and cessation of cell growth. Though assimilatory pathways were induced rapidly, a transient block in carbon flow to biomass synthesis occurred, and enzymatic assays suggested methylene tetrahydrofolate dehydrogenase as one control point. This "downstream priming" mechanism ensures that significant carbon flux through these pathways does not occur until they are fully induced, precluding the buildup of toxic intermediates. Most metabolites that are required for growth on both carbon sources did not change significantly, even though transcripts and enzymatic activities required for their production changed radically, underscoring the concept of metabolic setpoints. CONCLUSIONS/SIGNIFICANCE: This multi-level approach has resulted in new insights into the metabolic strategies carried out to effect this shift between two dramatically different modes of growth and identified a number of potential flux control and regulatory check points as a further step toward understanding metabolic adaptation and the cellular strategies employed to maintain metabolic setpoints.

  10. Growth rate and calcium carbonate accumulation of Halimeda macrolobaDecaisne (Chlorophyta: Halimedaceae in Thai waters

    Directory of Open Access Journals (Sweden)

    Jaruwan Mayakun

    2014-08-01

    Full Text Available Halimeda macroloba Decaisne can utilize the CO2 used for carbon fixation in photosynthesis and use bicarbonate as the main carbon source for calcification. Although Halimeda has been recognized as a carbon sink species, the calcium accumulation of Halimeda species in Thai waters remain poorly understood. In this study, the highest density of H. macroloba was 26 thalli/m2 and Halimeda quickly produced 1-2 new segments/thallus/day or 20.1 mg dry weight/thallus/day. Its calcium carbonate accumulation rate was 16.6 mg CaCO3 /thallus/day, or 82.46 % per thallus. In Thailand, however, only three scientific papers of growth rate and CaCO3 accumulation rate of H. macroloba have been found and collected. Of these records, the mean density was 26-104 thalli/m2 . The growth rate of H. macroloba was around 1-2 mg dry weight/day and the CaCO3 accumulation rate varied around 41-91%. Thus, Halimeda has a great potential to decrease the carbon dioxide concentration in the ocean.

  11. Differential Effect of Culture Temperature and Specific Growth Rate on CHO Cell Behavior in Chemostat Culture

    OpenAIRE

    Vergara, Mauricio; Becerra, Silvana; Berrios, Julio; Osses, Nelson; Reyes, Juan; Rodríguez-Moyá, María; Gonzalez, Ramon; Altamirano, Claudia

    2014-01-01

    Mild hypothermia condition in mammalian cell culture technology has been one of the main focuses of research for the development of breeding strategies to maximize productivity of these production systems. Despite the large number of studies that show positive effects of mild hypothermia on specific productivity of r-proteins, no experimental approach has addressed the indirect effect of lower temperatures on specific cell growth rate, nor how this condition possibly affects less specific pro...

  12. Life cycle and population growth rate of Caenorhabditis elegans studied by a new method

    OpenAIRE

    Schroeder Fabian; Muschiol Daniel; Traunspurger Walter

    2009-01-01

    Abstract Background The free-living nematode Caenorhabditis elegans is the predominant model organism in biological research, being used by a huge number of laboratories worldwide. Many researchers have evaluated life-history traits of C. elegans in investigations covering quite different aspects such as ecotoxicology, inbreeding depression and heterosis, dietary restriction/supplement, mutations, and ageing. Such traits include juvenile growth rates, age at sexual maturity, adult body size, ...

  13. Early development, survival and growth rates of the giant clam Tridacna crocea (Bivalvia: Tridacnidae)

    OpenAIRE

    Miguel Mies; Felipe Braga; Marcello Santos Scozzafave; Daniel Eduardo Lavanholi de Lemos; Paulo Yukio Gomes Sumida

    2012-01-01

    Tridacnid clams are conspicuous inhabitants of Indo-Pacific coral reefs and are traded and cultivated for the aquarium and food industries. In the present study, daily growth rates of larvae of the giant clam Tridacna crocea were determined in the laboratory during the first week of life. Adults were induced to spawn via intra-gonadal serotonin injection through the byssal orifice. After spawning oocytes were collected, fertilized and kept in 3 L glass beakers and raceways treated with antibi...

  14. Relationships between piglet growth rate and mammary gland size of the sow

    DEFF Research Database (Denmark)

    Nielsen, O.L.; Pedersen, Asger Roer; Sørensen, Martin Tang

    2001-01-01

    An experiment was conducted to study whether piglet growth rate is related to mammary gland size. It involved three primiparous sows and four multiparous sows that were fed ad libitum during the lactation period. The piglets received no creep feed. The weight and teat order of the piglets were.......22) did not reach significance. There were no significant correlations between piglet start weight and any of these mammary gland compositional traits....

  15. Testing the null hypothesis of no regime switching with an application to GDP growth rates

    OpenAIRE

    Marmer, Vadim

    2009-01-01

    This paper presents tests for the null hypothesis of no regime switching in Hamilton's (1989) regime switching model. The test procedures exploit similarities between regime switching models, autoregressions with measurement errors, and finite mixture models. The proposed tests are computationally simple and, contrary to likelihood based tests, have a standard distribution under the null. When the methodology is applied to US GDP growth rates, no strong evidence of regime switching is found.

  16. Intuitive calculation of the relativistic Rayleigh-Taylor instability linear growth rate

    OpenAIRE

    Bret, A.

    2011-01-01

    The Rayleigh-Taylor instability is a key process in many fields of Physics ranging from astrophysics to inertial confinement fusion. It is usually analyzed deriving the linearized fluid equations, but the physics behind the instability is not always clear. Recent works on this instability allow for an very intuitive understanding of the phenomenon and for a straightforward calculation of the linear growth rate. In this Letter, it is shown that the same reasoning allows for a direct derivation...

  17. Small Regulatory RNA-Induced Growth Rate Heterogeneity of Bacillus subtilis

    OpenAIRE

    Mars, Ruben A. T.; Nicolas, Pierre; Ciccolini, Mariano; Reilman, Ewoud; Reder, Alexander; Schaffer, Marc; Maeder, Ulrike; Voelker, Uwe; van Dijl, Jan Maarten; Denham, Emma L.

    2015-01-01

    Author Summary Bacterial cells that share the same genetic information can display very different phenotypes, even if they grow under identical conditions. Despite the relevance of this population heterogeneity for processes like drug resistance and development, the molecular players that induce heterogenic phenotypes are often not known. Here we report that in the Gram-positive model bacterium Bacillus subtilis a small regulatory RNA (sRNA) can induce heterogeneity in growth rates by increas...

  18. Effect of heat treatment on fatigue crack growth rate of inconel 690

    International Nuclear Information System (INIS)

    The effects of heat treatment on fatigue crack growth rates (FCGRs) of Inconel 690 have been investigated in terms of carbide morphology and grain size. Cycling tests in air at room temperature have shown that FCGR in low stress intensity factor range (ΔK) region can be effectively reduced by increasing the grain boundary carbide precipitate size and grain size. Decrease in FCGR is attributed to the crack tip blunting at the precipitates of grain boundary chromium carbides

  19. Reduced growth rate of tumors from melanoma B16 cells exposed to focused shock waves

    Czech Academy of Sciences Publication Activity Database

    Šunka, Pavel; Stelmashuk, Vitaliy; Beneš, J.; Poučková, P.

    Piscataway: IEEE, 2007 - (Umstattd, R.), s. 494-497. (IEEE Catalog Number: 06CH37746). ISBN 978-1-4244-0018-8. ISSN 1930-885X. [2006 IEEE International Power Modulator Conference. Washington, DC (US), 15.05.2006-19.05.2006] R&D Projects: GA ČR GA202/05/0685 Institutional research plan: CEZ:AV0Z20430508 Keywords : Shock waves * cavitations * melanoma cells * tumor growth rate Subject RIV: BL - Plasma and Gas Discharge Physics

  20. Feather growth rate and mass in nearctic passerines with variablemigratory behavior and molt pattern

    OpenAIRE

    De la Hera, I., Unanue, A., Aguirre, I.; DeSante, D.F.; Mila, B.

    2012-01-01

    Bird species vary greatly in the duration of their annual complete feather molt. However, such variation is not well documented in birds from many biogeographic areas, which restricts our understanding of the diversification of molt strategies. Recent research has revealed that molt duration can be estimated in passerines from ptilochronology-based measurements of the growth rate of their tail feathers. We used this approach to explore how molt duration varied in 98 Nearctic species that have...

  1. Ant larval demand reduces aphid colony growth rates in an ant-aphid interaction

    OpenAIRE

    Cook, James M.; Leather, Simon R; Oliver, Tom H.

    2012-01-01

    Ants often form mutualistic interactions with aphids, soliciting honeydew in return for protective services. Under certain circumstances, however, ants will prey upon aphids. In addition, in the presence of ants aphids may increase the quantity or quality of honeydew produced, which is costly. Through these mechanisms, ant attendance can reduce aphid colony growth rates. However, it is unknown whether demand from within the ant colony can affect the ant-aphid interaction. In a factorial exper...

  2. Subcritical crack growth and mechanical weathering: a new consideration of how moisture influences rock erosion rates.

    Science.gov (United States)

    Eppes, Martha-Cary; Keanini, Russell; Hancock, Gregory S.

    2016-04-01

    The contributions of moisture to the mechanical aspects of rock weathering and regolith production are poorly quantified. In particular, geomorphologists have largely overlooked the role of subcritical crack growth processes in physical weathering and the fact that moisture strongly influences the rates of those processes. This influence is irrespective of the function that moisture plays in stress loading mechanisms like freezing or hydration. Here we present a simple numerical model that explores the efficacy of subcritical crack growth in granite rock subaerially exposed under a range of moisture conditions. Because most weathering-related stress loading for rocks found at, or near, Earth's surface (hereafter surface rocks) is cyclic, we modeled crack growth using a novel combination of Paris' Law and Charles' Law. This combination allowed us to apply existing empirically-derived data for the stress corrosion index of Charles' Law to fatigue cracking. For stress, we focused on the relatively straightforward case of intergranular stresses that arise during solar-induced thermal cycling by conductive heat transfer, making the assumption that such stresses represent a universal minimum weathering stress experienced by all surface rocks. Because all other tensile weathering-related stresses would be additive in the context of crack growth, however, our model can be adapted to include other stress loading mechanisms. We validated our calculations using recently published thermal-stress-induced cracking rates. Our results demonstrate that 1) weathering-induced stresses as modeled herein, and as published by others, are sufficient to propagate fractures subcritically over long timescales with or without the presence of water 2) fracture propagation rates increase exponentially with respect to moisture, specifically relative humidity 3) fracture propagation rates driven by thermal cycling are strongly dependent on the magnitude of diurnal temperature ranges and the

  3. Cellular Injury of Cardiomyocytes during Hepatocyte Growth Factor Gene Transfection with Ultrasound-Triggered Bubble Liposome Destruction

    Directory of Open Access Journals (Sweden)

    Kazuo Komamura

    2011-01-01

    Full Text Available We transfected naked HGF plasmid DNA into cultured cardiomyocytes using a sonoporation method consisting of ultrasound-triggered bubble liposome destruction. We examined the effects on transfection efficiency of three concentrations of bubble liposome (1×106, 1×107, 1×108/mL, three concentrations of HGF DNA (60, 120, 180 μg/mL, two insonification times (30, 60 sec, and three incubation times (15, 60, 120 min. We found that low concentrations of bubble liposome and low concentrations of DNA provided the largest amount of the HGF protein expression by the sonoporated cardiomyocytes. Variation of insonification and incubation times did not affect the amount of product. Following insonification, cardiomyocytes showed cellular injury, as determined by a dye exclusion test. The extent of injury was most severe with the highest concentration of bubble liposome. In conclusion, there are some trade-offs between gene transfection efficiency and cellular injury using ultrasound-triggered bubble liposome destruction as a method for gene transfection.

  4. Investigation on application of synthetic nutrients for augmenting worm growth rate in vermicomposting

    Directory of Open Access Journals (Sweden)

    Kanimani Thiruganasambadam

    2012-06-01

    Full Text Available An investigation was carried out to scan the influence of synthetic nutrients on Vermicomposting. A mixture of six nutrients (Iron, Manganese, Zinc, Copper, Molybdenum and Boron was introduced to augment the growth of worms (Lumbricus rubellus and to ensure the higher digestion rate of the pre-composted bio-degradable organic waste. Initially green waste was collected from the local vegetable market and pre-composted for about three weeks. Then the pre-composted waste was placed in two identical glass vermireactors. Each reactor was loaded with equal volume of waste (0.024 m³ and worms (40 gm. The pre-composted waste was vermicomposted for a period of 21 days by applying nutrients in one reactor and the other was kept as control (without nutrient. The nutrients were applied in liquid form while moistening the reactor beds and the characteristics of the pre-composted waste, vermicasts and vermi growth rate were studied. Results revealed that the reactor added by nutrients performed better by achieving 41.34% higher waste volume reduction and 42% increase in the worm growth rate.

  5. Effects of incandescent radiation on photosynthesis, growth rate and yield of 'Waldmann's Green' leaf lettuce

    Science.gov (United States)

    Knight, S. L.; Mitchell, C. A.

    1989-01-01

    Effects of different ratios incandescent (ln) to fluorescent (Fl) radiation were tested on growth of 'Waldmann's Green' leaf lettuce (Lactuca sativa L.) in a controlled environment. After 4 days of treatment, dry weight, leaf area, relative growth rate (RGR), net assimilation rate (NAR), leaf area ratio (LAR) and photosynthetic rate (Pn) were greater for plants grown at 84 rather than 16% of total irradiance (82 W m-2) from ln lamps. Although leaf dry weight and area were 12-17% greater at 84% ln after the first 8 days of treatment, there were no differences in RGR or Pn between treatments during the last 4 days. If 84% ln was compared with 50% ln, all cumulative growth parameters, RGR, NAR and Pn were greater for 84% ln during the first 4 days of treatment. However, during the second 4 days, RGR was greater for the 50% ln treatment, resulting in no net difference in leaf dry weight or area between treatments. Shifting from 84 to 50% ln radiation between the first and second 4 days of treatment increased plant dry weight, leaf area, RGR and NAR relative to those under 84% ln for 8 days continuously.

  6. Increase of SiC sublimation growth rate by optimizing of powder packaging

    Science.gov (United States)

    Wang, Xiaolin; Cai, Dang; Zhang, Hui

    2007-07-01

    In this paper, a comprehensive model for silicon carbide (SiC) sublimation crystal growth considering powder packaging is presented. This model is based on heat and mass transfer of porous powder charge with different sizes of the particle and accounts for induction heating, powder charge sublimation, vapor transport, and porosity evolution in a SiC sublimation crystal growth system. The mechanism of vapor transport is proposed by introducing a driving force arising from temperature difference between powder charge and seed in the growth system. Powder porosity evolution and sublimation rate variations are predicted based on vapor transport mechanism. Effects of powder geometry, such as particle sizes, volume and size ratios of different particles, and driving forces on the sublimation rate are studied. In addition, simulation results for powder sublimation with and without a central hole are presented. The results indicate that the sublimation rate can be increased by optimizing the powder packaging, or by creating a hole in the center of packed powder.

  7. Intrinsic fatigue crack growth rates for Al-Li-Cu-Mg alloys in vacuum

    Science.gov (United States)

    Slavik, D. C.; Blankenship, C. P., Jr.; Starke, E. A., Jr.; Gangloff, R. P.

    1993-01-01

    The influences of microstructure and deformation mode on inert environment intrinsic fatigue crack propagation were investigated for Al-Li-Cu-Mg alloys AA2090, AA8090, and X2095 compared to AA2024. The amount of coherent shearable delta-prime (Al3Li) precipitates and extent of localized planar slip deformation were reduced by composition (increased Cu/Li in X2095) and heat treatment (double aging of AA8090). Intrinsic growth rates, obtained at high constant K(max) to minimize crack closure and in vacuum to eliminate any environmental effect, were alloy dependent; da/dN varied up to tenfold based on applied Delta-K or Delta-K/E. When compared based on a crack tip cyclic strain or opening displacement parameter, growth rates were equivalent for all alloys except X2095-T8, which exhibited unique fatigue crack growth resistance. Tortuous fatigue crack profiles and large fracture surface facets were observed for each Al-Li alloy independent of the precipitates present, particularly delta-prime, and the localized slip deformation structure. Reduced fatigue crack propagation rates for X2095 in vacuum are not explained by either residual crack closure or slip reversibility arguments; the origin of apparent slip band facets in a homogeneous slip alloy is unclear.

  8. Dynamics of medium motion affecting voltage growth rate in direct current exploding breakers

    International Nuclear Information System (INIS)

    The effect of medium motion dynamics on the rate of voltage growth in the switch-off arc on a mockup of the commutator is studied. The commutator mockup comprise cylindrical constant-radius current-carrying foil element (CCE); constant-height, variable-radius, disk charge of explosive; thin dielectric knife located in the middle of the channel; and massive dielectric rings limiting the medium scattering in the axial direction. Water and paraffin are used as a medium inside and outside the CCE. Investigations have been conducted with the following circuit parameters: capacitance equals 2.8x10-3 F, inductance equals 3x10-4 H, load resistance equals 1.11 Ohm, commutation current equals 10 kA. It is shown that at the current density per unit length of the CCE circumference of the order of 100 A/mm the arcing medium pressure of the switch-off arc does not produce an essential effect on the voltage growth on the arc. A direct relationship between the arcing medium motion rate and the voltage growth rate on the arc is found which permits to control the steepness of the voltage pulse front for solving the problems of pulse supply for different kind of systems

  9. Growth rate, protein:RNA ratio and stoichiometric homeostasis of submerged macrophytes under eutrophication stress

    Directory of Open Access Journals (Sweden)

    Xing W.

    2016-01-01

    Full Text Available Growth rate hypothesis (GRH and stoichiometric homeostasis of photoautotrophs have always been questioned. However, little is known about GRH and stoichiometric homeostasis of aquatic plants, especially submerged macrophytes. Therefore, we aim to test the GRH and explore stoichiometric homeostasis of four freshwater submerged macrophytes under eutrophication stress. At the single species level and the multi-species level, N:P ratios of Potamogeton maackianus, Myriophyllum spicatum, Vallisneria natans and Ceratophyllum demersum had no consistent trends with growth rates. However, protein:RNA ratios of P. maackianus, M. spicatum and V. natans all correlated negatively with growth rates, demonstrating GRH can apply to freshwater submerged macrophytes, even though they are threatening by eutrophication stress. Protein:RNA ratios positively correlated with N:P ratios in culture media and tissues in submerged macrophytes except in P. maackianus (30d, suggesting effects of varying N:P ratios in culture media on protein:RNA ratios are basically in concert with tissue N:P ratios under short-time eutrophication stress. Stoichiometric homeostasis coefficients (HN:P indicated submerged macrophytes have weak homeostasis. Stoichiometric homeostasis of V. natans was stronger than those of P. maackianus, M. spicatum and C. demersum. The differences in GRH and homeostasis of the four submerged macrophytes may be due to species traits.

  10. Intrauterine growth rate in pregnancies complicated by type 1, type 2 and gestational diabetes

    Science.gov (United States)

    Lim, E L; Burden, T; Marshall, S M; Davison, J M; Blott, M J; Waugh, J S J; Taylor, R

    2009-01-01

    Fetal macrosomia is a feature of all subtypes of maternal diabetes. The intrauterine time course of development of macrosomia in type 1, type 2 and gestational diabetes (GDM) could identify the times of more rapid growth, which differ as a result of different influences in subtypes of diabetes. Higher maternal weight in type 2 and GDM may be expected to contribute to macrosomia and the blood glucose control will exert an additional influence. Information was collected prospectively on 217 pregnancies in insulin-treated women at a single centre over a six-year period. All women were managed by a single team of obstetricians and diabetologists at a Joint Obstetric Medical Clinic. The rate of increase in abdominal circumference from 28 weeks was identical in each subtype of diabetes and there were no differences between subtypes at the earliest gestation assessed. Use of customized growth centiles showed rates of macrosomia to be similar in type 1, type 2 and GDM (43.0%, 50.0% and 41.8%, respectively). The intrauterine time course to macrosomia is similar in type 1, type 2 and GDM. The relationship of macrosomia to extent of elevation of mean blood glucose control is weak, implying a low threshold for maximal effect on the rate of fetal growth.

  11. Validating estimates of the growth rate of structure with modified gravity simulations

    CERN Document Server

    Barreira, Alexandre; Schmidt, Fabian

    2016-01-01

    We perform a consistent end-to-end validation of estimates of the growth rate of structure, described by the parameter combination $f\\sigma_8$, in modified gravity cosmologies. We consider an analysis pipeline based on the redshift-space distortion modelling of the clustering wedges statistic of the galaxy correlation function and apply it to mock catalogues of $\\Lambda{\\rm CDM}$ and the normal branch of DGP cosmologies. We employ a halo occupation distribution approach to construct our mocks, which we ensure resemble the CMASS sample from BOSS in terms of the total galaxy number density and large scale amplitude of the power spectrum monopole. We show that the clustering wedges model successfully recovers the true growth rate difference between DGP and $\\Lambda{\\rm CDM}$, even for cases with over 40% enhancement in $f\\sigma_8$ compared to $\\Lambda{\\rm CDM}$. The unbiased performance of the clustering wedges model allows us to use the growth rate values estimated from the BOSS LOWZ and CMASS samples to constr...

  12. Growth rates of lava domes with respect to viscosity of magmas

    Directory of Open Access Journals (Sweden)

    I. Yokoyama

    2005-06-01

    Full Text Available In the discussion of lava dome formation, viscosity of magma plays an important role. Measurements of viscosity of magmas in field and laboratory are briefly summarized. The types of lava dome emplacements are classified into two, squeeze- and spine-type, by kinetic processes. The squeeze-type is the formation of a dome as a result of squeezes of magma through conduits and the latter is solidified magma forced to ascend by underlying fluid magma. An important parameter in the formation of such lava domes is their growth rates. Lava domes of squeeze-type are governed by the Hagen-Poiseuille Law which involves their viscosoties and other eruption parameters. At present, the real viscosity of magmas at the site of lava dome is still inaccessible. In order to avoid uncertainty in viscosity of magmas, a conception of «macroscopic viscosity» is proposed, which involves effects of chemical components, mainly SiO2 and volatile material, crystals and temperature, and their changes with time. Lava dome formations during the 20th century are briefly examined and their growth rates are estimated. The relationship between the growth rates and the SiO2 content of the magma is statistically studied, and the macroscopic viscosity is empirically expressed as a function of SiO2 content. The linearity between the two parameters is reasonably interpreted. This means that formation processes of lava domes are dominantly controlled by macroscopic viscosity of magma.

  13. On growth-optimal tax rates and the issue of wealth inequalities

    Science.gov (United States)

    Bouchaud, Jean-Philippe

    2015-11-01

    We introduce a highly stylized, yet non trivial model of the economy, with a public and private sector coupled through a wealth tax and a redistribution policy. The model can be fully solved analytically, and allows one to address the question of optimal taxation and of wealth inequalities. We find that according to the assumption made on the relative performance of public and private sectors, three situations are possible. Not surprisingly, the optimal wealth tax rate is either 0% for a deeply dysfunctional government and/or highly productive private sector, or 100 % for a highly efficient public sector and/or debilitated/risk averse private investors. If the gap between the public/private performance is moderate, there is an optimal positive wealth tax rate maximizing economic growth, even -- counter-intuitively -- when the private sector generates more growth. The compromise between profitable private investments and taxation however leads to a residual level of inequalities. The mechanism leading to an optimal growth rate is related the well-known explore/exploit trade-off.

  14. Influence of Production System, Sex and Litter Size on Growth Rates in Turcana Lambs

    Directory of Open Access Journals (Sweden)

    Dinu Gavojdian

    2013-10-01

    Full Text Available Lamb meat production has become the main source of income in the Romanian sheep farming industry, representing over 66% of the total returns. Turcana breed represents over 70% of the national flock, and 92% of the sheep bred in western Romania. However, meat production potential and growth rates of the breed are low, and thus strategies to improve performance of the Turcana lambs need to be identified. Aim of the current research was to evaluate the effects that sex and litter size have on the growth rates of lambs from Turcana breed under extensive and semi-intensive production systems. Weaning weight was significantly (p≤0.001 influenced by the production system, with lambs reared extensively registering a average body weights of 18.23±0.094 kg at the age of 90 days, while the semi-intensively reared lambs registered an average weight of 20.19±0.082 kg. It was concluded that all three factors taken into study significantly influence growth rates in Turcana lambs and that weight of the lamb(s at the age of 28 days should be included as a selection trait within the Turcana breed genetic improvement plan.

  15. Threshold stress intensities and crack growth rates in tritium-exposed HERF stainless steels

    International Nuclear Information System (INIS)

    This paper reports on a falling-load compliance technique used to measure threshold stress intensities and crack growth rates in tritium-exposed-and- aged, high-energy-rate-forged (HERF) stainless steels. Triplicate 304L and 316 fracture toughness samples were exposed to high pressure tritium gas at 413 K, aged at 273 K for helium build-in from tritium decay, and then tested at room temperature. The samples contained about 740 appm tritium and 440 appm helium. The results showed that 304L had a lower threshold stress intensity (67.9 MPa-m1/2) than 316 (95.5 MPa-m1/2) and that the Stage II crack growth rates were, on average, more than an order of magnitude faster in 304L than in 316. During Stage II crack growth, each of the 304L samples showed periodic, order-of-magnitude changes in the crack velocities. These latter effects are apparently a result of the diffusion controlled process of concentrating tritium at the crack tip and/or the process of microcracks linking up to the main crack front. In both materials, the cracking was for the most part along grain- and-twin boundaries but glide-plane decohesion was also observed

  16. Effect of rotation on the growth rate of magnetogravitational instability of a viscoelastic medium

    International Nuclear Information System (INIS)

    In the present paper, we investigate the effect of rotation on the onset of gravitational collapse and the growth rate of magnetogravitational instability of a finitely electrically conducting viscoelastic medium under both strongly and weakly coupled plasma limits for transverse and longitudinal modes of wave propagation. A general dispersion relation, which is uniformly valid for both the transverse and longitudinal mode of wave propagation, is obtained using the normal mode analysis method. It is observed that the rotation has no effect on the instability criterion which governs the onset of gravitational collapse of the viscoelastic medium in the presence of a magnetic field for either the longitudinal or transverse mode of wave propagation in strongly coupled plasma (SCP) or weakly coupled plasma (WCP). Furthermore, the effects of rotation (Coriolis force), finite electrical resistivity and shear viscosity on the growth rate of Jeans instability in both SCP and WCP for transverse modes of propagation have been numerically calculated and the results obtained are depicted graphically. From these results, we concluded that the rotation reduces the growth rate of Jeans instability. (paper)

  17. Estimation of growth rate of Skeletonema costatum based on relative expression amount of PCNA gene

    Institute of Scientific and Technical Information of China (English)

    HE Shanying; YU Zhigang

    2008-01-01

    Partial sequence of Skeletonema costatum proliferating cell nuclear antigen (PCNA) gene was obtained by reverse transcriptase PCR(RT-PCR) and 3' rapid amplification of cDNA ends (3'-RACE) techniques.Based on the obtained PCNA and cytochrome b gene(Cyt b gene) sequences,a real-time fluorescent quantitative PCR (FQ-PCR) method was developed to detect the expres-sion S.costatum PCNA gene,and this method was applied to study the relationship between the growth rate of S.costatum and the average expression amount of PCNA gene in a single cell.The expression amount of PCNA gene had large variation in cells col-lected at different culture phases,and the trend was well consistent with the growth rate,which suggested that the expression amount of PCNA gene correlated well with the cell division,and the PCNA could be a promising indicator for the S.costatum cell proliferation.Furthermore,using the PCNA gene as the objective gene and the Cyt b gene as the house-keeping gene,a new method for estimating the in situ growth rate of S.costatum was established by analysis of the relative expression quantity (REQ) of the PCNA gene.

  18. The effect of solidification rate on the growth of small fatigue cracks in a cast 319-type aluminum alloy

    Energy Technology Data Exchange (ETDEWEB)

    Caton, M.J.; Jones, J.W.; Boileau, J.M.; Allison, J.E.

    1999-12-01

    A study was conducted to investigate the effect of solidification rate on the growth behavior of small fatigue cracks in a 319-type aluminum alloy, a common Al-Si-Cu alloy used in automotive castings. Fatigue specimens were taken from cast material that underwent a hot isostatic pressing (HIP) process in order to eliminate shrinkage pores and to facilitate the observation of surface-initiated cracks by replication. Naturally initiated surface cracks ranging in length from 17 {micro}m to 2 mm were measured using a replication technique. Growth rates of the small cracks were calculated as a function of the elastic stress-intensity-factor range ({Delta}K). Long-crack growth-rate data (10 mm {le} length {le} 25 mm) were obtained from compact-tension (CT) specimens, and comparison to the small-crack data indicates the existence of a significant small-crack effect in this alloy. The solidification rate is shown to have a significant influence on small-crack growth behavior, with faster solidification rates resulting in slower growth rates at equivalent {Delta}K levels. A stress-level effect is also observed for both solidification rates, with faster growth rates occurring at higher applied-stress amplitudes at a given {Delta}K. A crack-growth relation proposed by Nisitani and others is modified to give reasonable correlation of small-crack growth data to different solidification rates and stress levels.

  19. The effect of solidification rate on the growth of small fatigue cracks in a cast 319-type aluminum alloy

    Science.gov (United States)

    Caton, M. J.; Jones, J. Wayne; Boileau, J. M.; Allison, J. E.

    1999-12-01

    A study was conducted to investigate the effect of solidification rate on the growth behavior of small fatigue cracks in a 319-type aluminum alloy, a common Al-Si-Cu alloy used in automotive castings. Fatigue specimens were taken from cast material that underwent a hot isostatic pressing (HIP) process in order to eliminate shrinkage pores and to facilitate the observation of surface-initiated cracks by replication. Naturally initiated surface cracks ranging in length from 17 µm to 2 mm were measured using a replication technique. Growth rates of the small cracks were calculated as a function of the elastic stress-intensity-factor range (Δ K). Long-crack growth-rate data (10 mm≤length≤25 mm) were obtained from compact-tension (CT) specimens, and comparison to the small-crack data indicates the existence of a significant small-crack effect in this alloy. The solidification rate is shown to have a significant influence on small-crack growth behavior, with faster solidification rates resulting in slower growth rates at equivalent Δ K levels. A stress-level effect is also observed for both solidification rates, with faster growth rates occurring at higher applied-stress amplitudes at a given Δ K. A crack-growth relation proposed by Nisitani and others is modified to give reasonable correlation of small-crack growth data to different solidification rates and stress levels.

  20. Rate of Language Growth in Children with Hearing Loss in an Auditory-Verbal Early Intervention Program

    Science.gov (United States)

    Jackson, Carla Wood; Schatschneider, Christopher

    2013-01-01

    This longitudinal study explored the rate of language growth of children in an early intervention program providing auditory-verbal therapy. A retrospective investigation, the study applied a linear growth model to estimate a mean growth curve and the extent of individual variation in language performance on the Preschool Language Scale, 4th ed.…

  1. Determination of Cellular Processing Rates for a Trastuzumab-Maytansinoid Antibody-Drug Conjugate (ADC) Highlights Key Parameters for ADC Design.

    Science.gov (United States)

    Maass, Katie F; Kulkarni, Chethana; Betts, Alison M; Wittrup, K Dane

    2016-05-01

    Antibody-drug conjugates (ADCs) are a promising class of cancer therapeutics that combine the specificity of antibodies with the cytotoxic effects of payload drugs. A quantitative understanding of how ADCs are processed intracellularly can illustrate which processing steps most influence payload delivery, thus aiding the design of more effective ADCs. In this work, we develop a kinetic model for ADC cellular processing as well as generalizable methods based on flow cytometry and fluorescence imaging to parameterize this model. A number of key processing steps are included in the model: ADC binding to its target antigen, internalization via receptor-mediated endocytosis, proteolytic degradation of the ADC, efflux of the payload out of the cell, and payload binding to its intracellular target. The model was developed with a trastuzumab-maytansinoid ADC (TM-ADC) similar to trastuzumab-emtansine (T-DM1), which is used in the clinical treatment of HER2+ breast cancer. In three high-HER2-expressing cell lines (BT-474, NCI-N87, and SK-BR-3), we report for TM-ADC half-lives for internalization of 6-14 h, degradation of 18-25 h, and efflux rate of 44-73 h. Sensitivity analysis indicates that the internalization rate and efflux rate are key parameters for determining how much payload is delivered to a cell with TM-ADC. In addition, this model describing the cellular processing of ADCs can be incorporated into larger pharmacokinetics/pharmacodynamics models, as demonstrated in the associated companion paper. PMID:26912181

  2. High-growth rate YSZ thermal barrier coatings deposited by MOCVD demonstrate high thermal cycling lifetime

    International Nuclear Information System (INIS)

    Research highlights: → Use of thermochemical analysis to optimize stoichiometric ratios prior to experiments. → Thermodynamic analysis included a YO1.5-ZrO2 phase diagram to better describe solid solutions of YSZ. → Experimental growth resulted in high growth rate coatings with a columnar microstructure. → Coatings endured 1000 1-h thermal cycles (comparable to the lifetime of commercially viable EBPVD YSZ coating) with a much lower cost of fabrication. - Abstract: Yttria-stabilized zirconia (YSZ) thermal barrier coatings (TBC) were prepared by metalorganic chemical vapor deposition (MOCVD) using Y(OButn)3, Zr(OButn)4 precursors and O2 carrier gas. A thermodynamic analysis guided experiments by optimizing elemental molar (n) stoichiometric ratios for the (Zr-Y-O-C-H system). This analysis showed single-phase YSZ was favored at 950 deg. C, 1 kPa, nO/(nY + nZr) > 30, nY/(nY + nZr) = 0.06-0.10 (fixed nC, nH). Experimental YSZ growth had multiple phases (fcc, monoclinic), had a relatively high growth rate (43 μm/h, 1005 deg. C), had an Arrhenius dependence (845-950 deg. C, Ea = 53.8 ± 7.9 kJ/mol), had columnar grains (SEM analysis), and had a coating through-thickness nY/(nY + nZr) = 0.04 (EPMA analysis). Doubling the inlet yttrium precursor mole fraction resulted in fcc YSZ growth with a coating through-thickness nY/(nY + nZr) = 0.07. Hot-insertion thermal cycling of YSZ coatings on FeCrAlY bond coats showed >1000 h lifetime, matching current standards for EB-PVD YSZ coatings.

  3. Fatigue behaviour and crack growth rate of cryorolled Al 7075 alloy

    International Nuclear Information System (INIS)

    Highlights: → High cycle fatigue of cryorolled Al 7075 alloy has been investigated. → Cryorolled Al alloy showed significant enhancement in fatigue strength. → FCGR resistance of the ufg Al alloy is higher at higher values of applied stress. - Abstract: The effects of cryorolling (CR) on high cycle fatigue (HCF) and fatigue crack growth rate behaviour of Al 7075 alloy have been investigated in the present work. The Al 7075 alloy was rolled for different thickness reductions (40% and 70%) at cryogenic (liquid nitrogen) temperature and its tensile strength, fatigue life, and fatigue crack growth mechanism were studied by using tensile testing, constant amplitude stress controlled fatigue testing, and fatigue crack growth rate testing using load shedding (decreasing ΔK) technique. The microstructural characterization of the alloy was carried out by using Field emission scanning electron microscopy (FESEM). The cryorolled Al alloy after 70% thickness reduction exhibits ultrafine grain (ufg) structure as observed from its FESEM micrographs. The cryorolled Al 7075 alloys showed improved mechanical properties (Y.S, U.T.S, Impact energy and Fracture toughness are 430 Mpa, 530 Mpa, 21 J, 24 Mpa m1/2 for 40CR alloy) as compared to the bulk 7075 Al alloy. It is due to suppression of dynamic recovery and accumulation of higher dislocations density in the cryorolled Al alloys. The cryorolled Al alloy investigated under HCF regime of intermediate to low plastic strain amplitudes has shown the significant enhancement in fatigue strength as compared to the coarse grained (CG) bulk alloy due to effective grain refinement. Fatigue crack growth (FCGR) resistance of the ufg Al alloy has been found be higher, especially at higher values of applied stress intensity factor ΔK The reasons behind such crack growth retardation is due to diffused crack branching mechanism, interaction between a propagating crack and the increased amount of grain boundaries (GB), and steps developed

  4. Peat growth and carbon accumulation rates during the holocene in boreal mires

    International Nuclear Information System (INIS)

    This thesis is based on accumulation processes in northern mires. In the first study, problems concerning carbon 14 dating of peat were examined by fractionation of bulk peat samples and 14C AMS dating of the separate fractions. In the following studies, peat cores from twelve Swedish mire sites were investigated. Macrofossil analysis was performed on the sampled cores to describe and classify the plant communities during mire development. Between 6 to 18 14C AMS datings were performed on one core from each mire in order to estimate the peat growth and carbon accumulation rates for the identified plant communities. Different fractions within single peat bulk samples gave considerably differing 14 C ages. The range in age differed between mire types and depth. For accurate 14C dating, moss-stems, preferably of Sphagnum spp. are recommended. Both autogenic and allogenic factors, e.g. climate and developmental stage, respectively, were identified as important influences on carbon accumulation. Both peat growth and carbon accumulation rates differed between plant communities. The major factors explaining the variations in accumulation rates of the different plant communities were the amount of Carex and Sphagnum remains and the geographical position of the mire. Carbon accumulation rates decrease along with development in most mires. The results indicate that some mires may have alternated between being carbon sinks and sources, at least over the last several hundred years. The inter-annual variation in carbon accumulation is probably explained by climatic variations

  5. Analysis of Correlations between Economic Growth (Rate of Real GDP and the Underground Economy

    Directory of Open Access Journals (Sweden)

    Pripoaie Silviu

    2009-06-01

    Full Text Available Analysis of performance of any economy involves the measurement and correlation of threebasic elements: the rate of economic growth, the rate of inflation and unemployment rate. When the rateof growth (rate of real GDP is high, the production of goods and services is growing and thereforeincreasing the number of jobs, decrease unemployment and raise living standards. If the economy is inrecession phase, increasing fiscal pressure to ensure the necessary budgetary funds triggers complexeconomic mechanisms. Rules more strictly is that those who are not able to operate in the normaleconomy to slide towards the underground economy, and this not because he wants to tax evasion, butbecause they simply can not cope with new regulations. It is widely accepted in economic theory andpractice the idea that reliability scale macroeconomic indicators of a country is affected by size ofunderground economy and the various tests made so far on this subject, focusing either on the socialaspect or the economic or moral, or emphasizes the illegal or the edge of legality. This has led to variousstudies in this area do not provide comparable data or provide data to the contrary. Worldwide were putin place, however, some calculation methods provided that applied the same country and same period,the results are rarely consistent, sometimes even in fundamentally different.

  6. Study of failures in a rabbit line selected for growth rate

    Directory of Open Access Journals (Sweden)

    C. Naturil-Alfonso

    2016-03-01

    Full Text Available Selection for growth rate is negatively related with reproductive fitness. The aim of this work was to analyse the causes of fertility failure in rabbit does selected for growth rate and characterised for reproductive deficiencies (line R. In the experiment, 82 does were divided into 2 groups: naturally mated (NM and artificially inseminated (AI, to relate luteinizing hormone (LH concentration with ovulation induction and pregnancy rate by laparoscopic determination. Additionally, in 38 of these females ovulation rate and metabolites determination (leptin, NEFA, BOHB and glucose were analysed and perirenal fat thickness measurement and live body weight (LBW determined. The results showed that all ovulated does (both NM and AI presented higher concentrations of LH than non-ovulated females. In addition, non-ovulated females showed high levels of leptin and BOHB, as well as LBW. Females from line R have an inherit reduced fertility due to ovulation failure as a consequence of a reduction in LH release, which could be explained by a heavier body weight and higher leptin concentrations.

  7. EFFECTS OF INTEREST RATE DEREGULATION ON AGRICULTURAL FINANCE AND GROWTH IN NIGERIA

    Directory of Open Access Journals (Sweden)

    Louis O. ONYISHI

    2015-03-01

    Full Text Available The study examined the effects of interest rate deregulation on agricultural finance and growth in Nigeria. The study specifically ascertained the factors that determine the aggregate credit volume to agriculture within the periods of regulation and deregulation in the Nigerian economy, determined the effects of government finance interventions on agricultural sector performance in the Nigerian economy, determined the periodic effects of macroeconomic financial indicators on Agriculture’s gross domestic product (GDP contribution to Nigerian economy and estimated the level of real credit growth of agricultural finance in Nigeria. Descriptive statistics, Ordinary Least Squares (OLS regression technique and chow test were used for data analysis. The chow test showed that there was a significant differential effect on the aggregate credit volume to agricultural sector between the regulated and deregulated regimes. Interest rate was an important determinant of aggregate credit volume to the agricultural sector in Nigeria, especially during the deregulated period but monetary authorities should ensure appropriate determination of interest rate level that will break the double-edge effect of interest rates on savers and investors.

  8. Effects of N Forms and Rates on Vegetable Growth and Nitrate Accumulation

    Institute of Scientific and Technical Information of China (English)

    WANG Zhao-Hui; LI Sheng-Xiu

    2003-01-01

    Experiments were carried out on a vegetable field with Peking cabbage (Brassica pekinensis (Lour.)Rupr.), cabbage (Brassica chinensis var. Oleifera Makino and nemoto), green cabbage (Brassica chinensis L.), spinach (Spinacia oleracea L.) and rape (Brassica campestris L.) to study the effects of N forms and N rates on their growth and nitrate accumulation. The results indicated that application of ammonium chloride,ammonium nitrate, sodium nitrate and urea significantly increased the yields and nitrate concentrations of Peking cabbage and spinach. Although no significant difference was found in the yields after application of the 4 N forms, nitrate N increased nitrate accumulation in vegetables much more than ammonium N. The vegetable yields were not increased continuously with N rate increase, and oversupply of N reduced the plant growth, leading to a yield decline. This trend was also true for nitrate concentrations in some vegetables and at some sampling times. However, as a whole, the nitrate concentrations in vegetables were positively correlated with N rates. Thus, addition of N fertilizer to soil was the major cause for increases in nitrate concentrations in vegetables. Nitrate concentrations were much higher in roots, stems and petioles than in blades at any N rate.

  9. High Growth Rate Metal-Organic Molecular Beam Epitaxy for the Fabrication of GaAs Space Solar Cells

    Science.gov (United States)

    Freundlich, A.; Newman, F.; Monier, C.; Street, S.; Dargan, P.; Levy, M.

    2005-01-01

    In this work it is shown that high quality GaAs photovoltaic devices can be produced by Molecular Beam Epitaxy (MBE) with growth rates comparable to metal-organic chemical vapor deposition (MOCVD) through the subsitution of group III solid sources by metal-organic compounds. The influence the III/V flux-ratio and growth temperatures in maintaining a two dimensional layer by layer growth mode and achieving high growth rates with low residual background impurities is investigated. Finally subsequent to the study of the optimization of n- and p doping of such high growth rate epilayers, results from a preliminary attempt in the fabrication of GaAs photovoltaic devices such as tunnel diodes and solar cells using the proposed high growth rate approach are reported.

  10. ECOHAB: Van Dolah_F- Karenia brevis Cell Cycle Analysis for Determination of In Situ Growth Rates (NODC Accession 0000538)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The reported growth rates of Karenia brevis vary from 0.2 to 0.5 divisions per day, both in laboratory and field populations observed. This growth rate alone is not...

  11. Consequences of insect herbivory on grape fine root systems with different growth rates.

    Science.gov (United States)

    Bauerle, T L; Eissenstat, D M; Granett, J; Gardner, D M; Smart, D R

    2007-07-01

    Herbivory tolerance has been linked to plant growth rate where plants with fast growth rates are hypothesized to be more tolerant of herbivory than slower-growing plants. Evidence supporting this theory has been taken primarily from observations of aboveground organs but rarely from roots. Grapevines differing in overall rates of new root production, were studied in Napa Valley, California over two growing seasons in an established vineyard infested with the sucking insect, grape phylloxera (Daktulosphaira vitifoliae Fitch). The experimental vineyard allowed for the comparison of two root systems that differed in rates of new root tip production (a 'fast grower', Vitis berlandieri x Vitis rupestris cv. 1103P, and a slower-growing stock, Vitis riparia x Vitis rupestris cv. 101-14 Mgt). Each root system was grafted with a genetically identical shoot system (Vitis vinifera cv. Merlot). Using minirhizotrons, we did not observe any evidence of spatial or temporal avoidance of insect populations by root growth. Insect infestations were abundant throughout the soil profile, and seasonal peaks in phylloxera populations generally closely followed peaks in new root production. Our data supported the hypothesis that insect infestation was proportional to the number of growing tips, as indicated by similar per cent infestation in spite of a threefold difference in root tip production. In addition, infested roots of the fast-growing rootstock exhibited somewhat shorter median lifespans (60 d) than the slower-growing rootstock (85 d). Lifespans of uninfested roots were similar for the two rootstocks (200 d). As a consequence of greater root mortality of younger roots, infested root populations in the fast-growing rootstock had an older age structure. While there does not seem to be a trade-off between potential growth rate and relative rate of root infestation in these cultivars, our study indicates that a fast-growing root system may more readily shed infested roots that are

  12. Modeling Nucleation, Growth, and Ostwald Ripening in Crystallization Processes: A Comparison between Population Balance and Kinetic Rate Equation

    OpenAIRE

    Vetter, Thomas; Iggland, Martin; Ochsenbein, David R; Haenseler, Flurin S; Mazzotti, Marco

    2013-01-01

    In this work, we investigate a comprehensive model describing nucleation, growth and Ostwald ripening based on the kinetic rate equation and compare it to commonly used population balance equation models that either describe nucleation and crystal growth or crystal growth and Ostwald ripening. The kinetic rate equation gives a microscopic description of crystallization, i.e., the process is seen as an attachment and detachment of crystals of different sizes to and from each other, thereby cha...

  13. THE ROLE OF THE STATE IN ACHIEVING HIGH RATE OF ECONOMIC GROWTH. EXPERIENCES OF INDIA AND PAKISTAN: THE COMPARISON

    OpenAIRE

    Michal Litwinski

    2013-01-01

    The influence of state institutions on economic growth dynamics is an important subject of analysis in economics literature. The purpose of this article is to compare determinants of growth rate in India and Pakistan in the years 1988 to 2012. The subject of analysis will be factors associated both with neoclassical growth model (capital, labor) and with institutional economy (political and economic institutions). Nowadays in India and Pakistan we can observe relatively high rates of economic...

  14. Prediction of PWSCC in nickel base alloys using crack growth rate models

    International Nuclear Information System (INIS)

    The Ford/Andresen slip dissolution SCC model, originally developed for stainless steel components in BWR environments, has been applied to Alloy 600 and Alloy X-750 tested in deaerated pure water chemistry. A method is described whereby the crack growth rates measured in compact tension specimens can be used to estimate crack growth in a component. Good agreement was found between model prediction and measured SCC in X-750 threaded fasteners over a wide range of temperatures, stresses, and material condition. Most data support the basic assumption of this model that cracks initiate early in life. The evidence supporting a particular SCC mechanism is mixed. Electrochemical repassivation data and estimates of oxide fracture strain indicate that the slip dissolution model can account for the observed crack growth rates, provided primary rather than secondary creep rates are used. However, approximately 100 cross-sectional TEM foils of SCC cracks including crack tips reveal no evidence of enhanced plasticity or unique dislocation patterns at the crack tip or along the crack to support a classic slip dissolution mechanism. No voids, hydrides,, or microcracks are found in the vicinity of the crack tips creating doubt about classic hydrogen related mechanisms. The bulk oxide films exhibit a surface oxide which is often different than the oxide found within a crack. Although bulk chromium concentration affects the rate of SCC, analytical data indicates the mechanism does not result from chromium depletion at the grain boundaries. The overall findings support a corrosion/dissolution mechanism but not one necessarily related to slip at the crack tip. (author). 12 refs, 27 figs

  15. Effects of low power microwave radiation on biological activity of Collagenase enzyme and growth rate of S. Cerevisiae yeast

    Science.gov (United States)

    Alsuhaim, Hamad S.; Vojisavljevic, Vuk; Pirogova, E.

    2013-12-01

    Recently, microwave radiation, a type/subset of non-ionizing electromagnetic radiation (EMR) has been widely used in industry, medicine, as well as food technology and mobile communication. Use of mobile phones is rapidly growing. Four years from now, 5.1 billion people will be mobile phone users around the globe - almost 1 billion more mobile users than the 4.3 billion people worldwide using them now. Consequently, exposure to weak radiofrequency/microwave radiation generated by these devices is markedly increasing. Accordingly, public concern about potential hazards on human health is mounting [1]. Thermal effects of radiofrequency/microwave radiation are very well-known and extensively studied. Of particular interest are non-thermal effects of microwave exposures on biological systems. Nonthermal effects are described as changes in cellular metabolism caused by both resonance absorption and induced EMR and are often accompanied by a specific biological response. Non-thermal biological effects are measurable changes in biological systems that may or may not be associated with adverse health effects. In this study we studied non-thermal effects of low power microwave exposures on kinetics of L-lactate dehydrogenase enzyme and growth rate of yeast Saccharomyces Cerevisiae strains type II. The selected model systems were continuously exposed to microwave radiation at the frequency of 968MHz and power of 10dBm using the designed and constructed (custom made) Transverse Electro-Magnetic (TEM) cell [2]. The findings reveal that microwave radiation at 968MHz and power of 10dBm inhibits L-lactate dehydrogenase enzyme activity by 26% and increases significantly (15%) the proliferation rate of yeast cells.

  16. Spherical sapphire single-crystal synthesis by aerodynamic levitation with high growth rate

    International Nuclear Information System (INIS)

    This article describes a technique for forming spherical Al2O3 single crystals by an aerodynamic levitator by applying the unidirectional solidification method. A levitation method intrinsically produces a spherical material. In addition, both the focused laser beam heating and the gas flows to the sample trapped in the levitator generate a steep temperature gradient in the molten sample, enabling the sample to grow with high growth rate. Spherical sapphire single-crystal production consists of two processes. First step is to solidify the molten sample unidirectionally from polycrystalline parts at the bottom of the sample. This sample was almost a single crystal with polycrystalline parts remaining just around the bottom. The crystal is then revolved before the second step. In the second step the revolved crystal was remelted from the polycrystalline part and solidified from the seed, resulting in complete single-crystal production. The x-ray Laue and crossed nicol experiment results for the Al2O3 spherical crystal with 2 mm diameter demonstrated that twin-free bulk single crystal had been produced. There were no macroscopic voids or cracks in the crystal at 60 mm/h growth rates in both steps. In addition, a hexagonal shape of the crystal seems to be the habit-plane of a natural corundum. This indicates the growth direction was along the c-axis of a sapphire

  17. Balancing drug resistance and growth rates via compensatory mutations in the Plasmodium falciparum chloroquine resistance transporter.

    Science.gov (United States)

    Petersen, Ines; Gabryszewski, Stanislaw J; Johnston, Geoffrey L; Dhingra, Satish K; Ecker, Andrea; Lewis, Rebecca E; de Almeida, Mariana Justino; Straimer, Judith; Henrich, Philipp P; Palatulan, Eugene; Johnson, David J; Coburn-Flynn, Olivia; Sanchez, Cecilia; Lehane, Adele M; Lanzer, Michael; Fidock, David A

    2015-07-01

    The widespread use of chloroquine to treat Plasmodium falciparum infections has resulted in the selection and dissemination of variant haplotypes of the primary resistance determinant PfCRT. These haplotypes have encountered drug pressure and within-host competition with wild-type drug-sensitive parasites. To examine these selective forces in vitro, we genetically engineered P. falciparum to express geographically diverse PfCRT haplotypes. Variant alleles from the Philippines (PH1 and PH2, which differ solely by the C72S mutation) both conferred a moderate gain of chloroquine resistance and a reduction in growth rates in vitro. Of the two, PH2 showed higher IC50 values, contrasting with reduced growth. Furthermore, a highly mutated pfcrt allele from Cambodia (Cam734) conferred moderate chloroquine resistance and enhanced growth rates, when tested against wild-type pfcrt in co-culture competition assays. These three alleles mediated cross-resistance to amodiaquine, an antimalarial drug widely used in Africa. Each allele, along with the globally prevalent Dd2 and 7G8 alleles, rendered parasites more susceptible to lumefantrine, the partner drug used in the leading first-line artemisinin-based combination therapy. These data reveal ongoing region-specific evolution of PfCRT that impacts drug susceptibility and relative fitness in settings of mixed infections, and raise important considerations about optimal agents to treat chloroquine-resistant malaria. PMID:25898991

  18. Growth and mortality rates of bigeye tuna Thunnus obesus (Perciformes: Scombridae) in the central Atlantic Ocean.

    Science.gov (United States)

    Zhu, Guoping; Xu, Liuxiong; Zhou, Yingqi; Chen, Xinjun

    2009-01-01

    Age and growth parameters were estimated for bigeye tuna Thunnus obesus Lowe, 1839 sampled from China longline fisheries in the central Atlantic Ocean from October 2002 to July 2003 and from August 2004 to March 2005. The von Bertalanffy growth parameters were estimated at L(infinity)=217.9 cm fork length, k=0.23 year(-1), and t(0)=-0.44 year. The total mortality rate (Z) was estimated to be from 0.82 to 1.02, the fishing mortality (F) and the natural mortality were 0.54 year(-1) and 0.39 year(-1), respectively. The exploitation ratio (E) was 0.35. This study provides the detailed estimates of growth and mortality rate for bigeye tuna in the central Atlantic Ocean, which can be used as biological input parameters in further stock evaluations in this region. However, age analysis, additional validation of the size composition and stock structure are needed for future studies. PMID:19637690

  19. Effects of Growth Environment and Ulking Rate on Cyanogenic Potential of Cassava Tuerous Roots

    International Nuclear Information System (INIS)

    Various abiotic factors affect the pattern of growth and accumulation of cyanogenic glucosides in cassava plants. Five cassava genotypes were planted in a wet and a dry agro-ecological zone and analyzed at 4, 6, 8, 10 and 12 months after planting for tuberous root bulking rate and cyanogenic potential. Cassava plants at Ibadan (the wetter zone) had higher tuberous roots bulking rate and lower cynogenic potential than those planted at Minjibir (the drier zone). Root bulking rate at Ibadan increased from 4 to 6 months after planting, fell to 10 months, and then levelled off thereafter. At Majorana, bulking rate increased from 4 to 6 months, levelling off u pto 8 months after planting, and then falling slightly u pto to 10 months, and rising gradually u pto 12 months after planting. At Minijibir, the 6-8 months after planting period coincided with drought and the highest root bulking rate but increasing cyanogenic potential. Similarly, at Ibadan the 6-8 months after planting period coincided with drought and the highest root bulking rate but increasing cyanogenic potential. Despite the onset of drought, bulking continued up to 8 months after planting, falling u pto 10 months and levelling off thereafter at both agro-ecological zones. However, whereas cyanogenic potential rose rapidly after 8 months to peak at 10 months, and levelling off up to 12 months at Minjibir, cyanogenic potential levelled of after 8 u pto 12 months at Ibadan. Correlation and regression analysis suggested that root bulking rate and cyanogenic potential were negatively associated, meaning that an increase in root bulking rate would lead to corresponding decrease in it's cyanogenic potential which is highly desirable. This study has demonstrated that whereas the plant age and genotypic effects are not important factors in determining tuberous roots bulking rate and cyanogenic potential of cassava, the agro-ecological zone effect is an important factor in determining them

  20. Treatment with kaempferol suppresses breast cancer cell growth caused by estrogen and triclosan in cellular and xenograft breast cancer models.

    Science.gov (United States)

    Kim, Seung-Hee; Hwang, Kyung-A; Choi, Kyung-Chul

    2016-02-01

    As a phytoestrogen, kaempferol (Kaem) is one of bioflavonoids, which are found in a variety of vegetables including broccoli, tea and tomato. In this study, the antiproliferative effects of Kaem in triclosn (TCS)-induced cell growth were examined in MCF-7 breast cancer cells. TCS promoted the cell viability of MCF-7 cells via estrogen receptor α (ERα) as did 17β-estradiol (E2), a positive control. On the other hand, Kaem significantly suppressed E2 or TCS-induced cell growth. To elucidate the molecular mechanisms of TCS and Kaem, alterations in the expressions of cell cycle, apoptosis and metastasis-related genes were identified using western blot assay. The treatment of the cells with TCS up-regulated the protein expressions of cyclin D1, cyclin E and cathepsin D, while down-regulated p21 and bax expressions. Kaem reversed TCS-induced gene expressions in an opposite manner. The phosphorylation of IRS-1, AKT, MEK1/2 and ERK was increased by TCS, indicating that TCS induced MCF-7 cell proliferation via nongenomic ER signaling pathway associated with IGF-1R. Kaem presented an antagonistic activity on this signaling by down-regulating the protein expression of pIRS-1, pAkt and pMEK1/2 promoted by E2 or TCS. In an in vivo xenografted mouse model, tumor growth was induced by treatment with E2 or TCS, which was identified in the measurement of tumor volume, hematoxylin and eosin staining, bromodeoxyuridine and immunohistochemistry assay. On the contrary, E2 or TCS-induced breast tumor growth was inhibited by co-treatment with Kaem, which is consistent with in vitro results. Taken together, these results revealed that Kaem has an anticancer effect against procancer activity of E2 or TCS, a xenoestrogen, in breast cancer and may be suggested as a prominent agent to neutralize breast cancer risk caused by TCS. PMID:26878784

  1. Effect of temperature on sulphate reduction, growth rate and growth yield in five psychrophilic sulphate-reducing bacteria from Arctic sediments

    DEFF Research Database (Denmark)

    Knoblauch, C.; Jørgensen, BB

    1999-01-01

    Five psychrophilic sulphate-reducing bacteria (strains ASv26, LSv21, PSv29, LSv54 and LSv514) isolated from Arctic sediments were examined for their adaptation to permanently low temperatures, All strains grew at -1.8 degrees C, the freezing point of sea water, but their optimum temperature for...... those at T(opt). Short-term incubations of exponentially growing cultures showed that the highest sulphate reduction rates occurred 2-9 degrees C above T(opt). In contrast to growth and sulphate reduction rates, growth yields of strains ASv26, LSv54 and PSv29 were almost constant between -1.8 degrees C...... and T(opt). For strains LSv21 and LSv514, however, growth yields were highest at the lowest temperatures, around 0 degrees C. The results indicate that psychrophilic sulphate-reducing bacteria are specially adapted to permanently low temperatures by high relative growth rates and high growth yields at...

  2. Growth rate control and solid-gas modeling of TFA-YBa2Cu3O7 thin film processing

    International Nuclear Information System (INIS)

    The trifluoroacetate metal-organic decomposition route to YBa2Cu3O7 film growth was investigated in order to bring new insights in the growth mechanism and its dependence on processing conditions and critical current density. Precursor films were processed on LaAlO3 substrates at different total pressure, oxygen partial pressure, water vapor partial pressure, and volume gas flow rate keeping the growth temperature at 740 0C. The influence of these various experimental parameters on the film growth rate, which was evaluated by in situ electrical resistance measurements, was studied thoroughly. It was found that the growth rate is nearly independent of the oxygen pressure and proportional to the square root of the water pressure. Additionally, the growth rate increases with a decrease of the total pressure or an increase of the gas flow rate. An empirical multi-exponential model simulates the experimental data, however, a better understanding was achieved using a theoretical solid-gas reaction-diffusion model, including both the diffusion of the product HF gas from the surface and the chemical reaction kinetics at the YBCO/precursor interface. A complex cross-linked relationship between the film growth rate and the processing parameters has been properly verified from the experimental data. Finally we showed that the growth rate is an important parameter influencing the critical current densities of YBCO films because it controls the nucleation of non-c-axis oriented grains.

  3. Specific Growth Rate Determines the Sensitivity of Escherichia coli to Lactic Acid Stress: Implications for Predictive Microbiology

    Directory of Open Access Journals (Sweden)

    Roland Lindqvist

    2014-01-01

    Full Text Available This study tested the hypothesis that sensitivity of Escherichia coli to lactic acid at concentrations relevant for fermented sausages (pH 4.6, 150 mM lactic acid, aw=0.92, temperature = 20 or 27°C increases with increasing growth rate. For E. coli strain 683 cultured in TSB in chemostat or batch, subsequent inactivation rates when exposed to lactic acid stress increased with increasing growth rate at harvest. A linear relationship between growth rate at harvest and inactivation rate was found to describe both batch and chemostat cultures. The maximum difference in T90, the estimated times for a one-log reduction, was 10 hours between bacteria harvested during the first 3 hours of batch culture, that is, at different growth rates. A 10-hour difference in T90 would correspond to measuring inactivation at 33°C or 45°C instead of 37°C based on relationships between temperature and inactivation. At similar harvest growth rates, inactivation rates were lower for bacteria cultured at 37°C than at 15–20°C. As demonstrated for E. coli 683, culture conditions leading to variable growth rates may contribute to variable lactic acid inactivation rates. Findings emphasize the use and reporting of standardised culture conditions and can have implications for the interpretation of data when developing inactivation models.

  4. "Effects of agitation rate on the growth of Mycena SP and production of antifungal agents "

    Directory of Open Access Journals (Sweden)

    Vahidi H

    2002-07-01

    Full Text Available Impeller speed or agitation rate plays a significant role in the growth of microorganism especially basidiomycetes and production of bioactive compounds via transfer of oxygen and mass. In this investigation the efferent impeller speeds on morphology, biomass concentration and production of bioactive compounds with antifungal activity were studied using a 5-liter fermenter. It was found that use of different impeller speeds (300 , 450 and 600 rpm resulted in various growth pattern and productivity. Impeller speed of 600 rpm gave a tow biomass concentration and low production of antifungal agent and the best result was obtained when impeller speed was adjusted to 450 rpm. Biomass concentration and productivity in the case of 300 rpm was less than that of 450 but higher than of 600 rpm.

  5. Growth rate analysis of scalar gradients in generalized surface quasigeostrophic equations of ideal fluids

    Science.gov (United States)

    Ohkitani, Koji

    2011-03-01

    The growth rates of scalar gradients are studied numerically and analytically in a family of two-dimensional (2D) incompressible fluid equations related to the surface quasigeostrophic (SQG) equation. The active scalar is related to the stream function ψ by θ=(-△)α/2ψ(0⩽α⩽2). A notable difference is observed in a comparison of the instantaneous growth rates in Lp and in L∞ norms, depending on the stage of the time evolution. The crux is the phase-shift effect of singular integral operators, which displaces the peak location of the scalar gradient from that of the strain rate. On this basis, a method of detecting such a dislocation is proposed in view of the importance of their coalescence needed for a possible blow-up. Moreover, it is found in the long-time evolution that a solution of the SQG equation (whose regularity is not known) is less singular than that of the 2D Euler equations (known to be regular) on the time interval covered by this computation. This consistently expands an earlier observation by Majda and Tabak [Physica DPDNPDT0167-278910.1016/0167-2789(96)00114-5 98, 515 (1996).] in some detail. A 1D model problem is discussed to illustrate the present method, and extensions to the 3D case are also are briefly discussed.

  6. Effects of Synbiotic (Biomin Imbo on Growth Performance, Survival Rate, Reproductive Parameters of Angelfish (Pterophyllum scalare

    Directory of Open Access Journals (Sweden)

    Hamed NEKOUBIN

    2012-12-01

    Full Text Available This study was carried out to evaluate the effect of synbiotic (Biomin imbo on growth performance, survival rate and reproductive parameters of Angelfish (Pterophyllum scalare via supplementation with Biomar. Four levels of Biomar experimental diets (54 % protein and 14 % lipid were prepared by adding synbiotic (0.15, 0.5, 0.75, 1 g/Kg at a basal diet (Biomar and the Angelfish larvae in experimental treatments were fed four levels of synbiotic with 5 percent body weight (3 times a day. The larvae in the control treatment were fed without supplemented Biomar. The results showed that larvae fed on the synbiotic had significantly increased final body weight in comparison with the control treatment. After 90 days, 5 adult female and male Angelfish were divided from each treatment. The results showed that fecundity in experimental treatments increased in comparison with the control treatment. The synbiotic also had positive effects on hatching rate in comparison with those in the control treatment but, there were no significant differences (P > 0.05 among treatments. The synbiotic also had significant positive effects on the specific growth rate (SGR and feed conversation efficiency (FCE in comparison to those fed the control treatment, however treatment T3 was more than T4 (T3 > T4 > T2 > T1 > control treatment.

  7. Influence of macrophyte decomposition on growth rate and community structure of Okefenokee Swamp bacterioplankton

    International Nuclear Information System (INIS)

    Dissolved substances released during decomposition of the white water lily (Nymphaea odorata) can alter the growth rate of Okefenokee Swamp bacterioplankton. In microcosm experiments dissolved compounds released bacterioplankton, followed by a period of intense bacterial growth. Rates of [3H]thymidine incorporation and turnover of dissolved D-glucose were depressed by over 85%, 3 h after the addition of Nymphaea leachates to microcosms containing Okefenokee Swamp water. Bacterial activity subsequently recovered; after 20 h [3H]thymidine incorporation in leachate-treated microcosms was 10-fold greater than that in control microcosms. The recovery of activity was due to a shift in the composition of the bacterial population toward resistance to the inhibitory compounds present in Nymphaea leachates. Inhibitory compounds released during the decomposition of aquatic macrophytes thus act as selective agents which alter the community structure of the bacterial population with respect to leachate resistance. Soluble compounds derived from macrophyte decomposition influence the rate of bacterial secondary production and the availability of microbial biomass to microconsumers

  8. Levels of polyunsaturated fatty acids correlate with growth rate in plant cell cultures

    Science.gov (United States)

    Meï, Coline; Michaud, Morgane; Cussac, Mathilde; Albrieux, Catherine; Gros, Valérie; Maréchal, Eric; Block, Maryse A.; Jouhet, Juliette; Rébeillé, Fabrice

    2015-01-01

    In higher plants, fatty acids (FAs) with 18 carbons (18C) represent about 70% of total FAs, the most abundant species being 18:2 and 18:3. These two polyunsaturated FAs (PUFAs) represent about 55% of total FAs in Arabidopsis cell suspension cultures, whereas 18:1 represents about 10%. The level of PUFAs may vary, depending on ill-defined factors. Here, we compared various sets of plant cell cultures and noticed a correlation between the growth rate of a cell population and the level of unsaturation of 18C FAs. These observations suggest that the final level of PUFAs might depend in part on the rate of cell division, and that FAD2 and FAD3 desaturases, which are respectively responsible for the formation of 18:2 and 18:3 on phospholipids, have limiting activities in fast-growing cultures. In plant cell culture, phosphate (Pi) deprivation is known to impair cell division and to trigger lipid remodeling. We observed that Pi starvation had no effect on the expression of FAD genes, and that the level of PUFAs in this situation was also correlated with the growth rate. Thus, the level of PUFAs appears as a hallmark in determining cell maturity and aging. PMID:26469123

  9. Hot spring siliceous stromatolites from Yellowstone National Park: assessing growth rate and laminae formation.

    Science.gov (United States)

    Berelson, W M; Corsetti, F A; Pepe-Ranney, C; Hammond, D E; Beaumont, W; Spear, J R

    2011-09-01

    Stromatolites are commonly interpreted as evidence of ancient microbial life, yet stromatolite morphogenesis is poorly understood. We apply radiometric tracer and dating techniques, molecular analyses and growth experiments to investigate siliceous stromatolite morphogenesis in Obsidian Pool Prime (OPP), a hot spring in Yellowstone National Park. We examine rates of stromatolite growth and the environmental and/or biologic conditions that affect lamination formation and preservation, both difficult features to constrain in ancient examples. The "main body" of the stromatolite is composed of finely laminated, porous, light-dark couplets of erect (surface normal) and reclining (surface parallel) silicified filamentous bacteria, interrupted by a less-distinct, well-cemented "drape" lamination. Results from dating studies indicate a growth rate of 1-5 cm year(-1) ; however, growth is punctuated. (14)C as a tracer demonstrates that stromatolite cyanobacterial communities fix CO(2) derived from two sources, vent water (radiocarbon dead) and the atmosphere (modern (14)C). The drape facies contained a greater proportion of atmospheric CO(2) and more robust silica cementation (vs. the main body facies), which we interpret as formation when spring level was lower. Systematic changes in lamination style are likely related to environmental forcing and larger scale features (tectonic, climatic). Although the OPP stromatolites are composed of silica and most ancient forms are carbonate, their fine lamination texture requires early lithification. Without early lithification, whether silica or carbonate, it is unlikely that a finely laminated structure representing an ancient microbial mat would be preserved. In OPP, lithification on the nearly diurnal time scale is likely related to temperature control on silica solubility. PMID:21777367

  10. Uniaxial Compression of Cellular Materials at a 10-1 s-1 Strain Rate Simultaneously with Synchrotron X-ray Computed Tomographic Imaging

    International Nuclear Information System (INIS)

    The topic is presented as a series of slides. Motivation for the work included the following: X-ray tomography is a fantastic technique for characterizing a material's starting structure as well as for non-destructive, in situ experiments to investigate material response; 3D X-ray tomography is needed to fully characterize the morphology of cellular materials; and synchrotron micro-CT can capture 3D images without pausing experiment. Among the conclusions reached are these: High-rate radiographic and tomographic imaging (0.25 s 3D frame rate) using synchrotron CT can capture full 3D images of hyper-elastic materials at a 10-2 strain rate; dynamic true in situ uniaxial loading can be accurately captured; the three stages of compression can be imaged: bending, buckling, and breaking; implementation of linear modeling is completed; meshes have been imported into LANL modeling codes--testing and validation is underway and direct comparison and validation between in situ data and modeled mechanical response is possible.

  11. Uniaxial Compression of Cellular Materials at a 10-1 s-1 Strain Rate Simultaneously with Synchrotron X-ray Computed Tomographic Imaging

    Energy Technology Data Exchange (ETDEWEB)

    Patterson, Brian M. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-03-01

    The topic is presented as a series of slides. Motivation for the work included the following: X-ray tomography is a fantastic technique for characterizing a material’s starting structure as well as for non-destructive, in situ experiments to investigate material response; 3D X-ray tomography is needed to fully characterize the morphology of cellular materials; and synchrotron micro-CT can capture 3D images without pausing experiment. Among the conclusions reached are these: High-rate radiographic and tomographic imaging (0.25 s 3D frame rate) using synchrotron CT can capture full 3D images of hyper-elastic materials at a 10-2 strain rate; dynamic true in situ uniaxial loading can be accurately captured; the three stages of compression can be imaged: bending, buckling, and breaking; implementation of linear modeling is completed; meshes have been imported into LANL modeling codes--testing and validation is underway and direct comparison and validation between in situ data and modeled mechanical response is possible.

  12. Cellular and molecular insight into the inhibition of primary root growth of Arabidopsis induced by peptaibols, a class of linear peptide antibiotics mainly produced by Trichoderma spp.

    Science.gov (United States)

    Shi, Wei-Ling; Chen, Xiu-Lan; Wang, Li-Xia; Gong, Zhi-Ting; Li, Shuyu; Li, Chun-Long; Xie, Bin-Bin; Zhang, Wei; Shi, Mei; Li, Chuanyou; Zhang, Yu-Zhong; Song, Xiao-Yan

    2016-04-01

    Trichodermaspp. are well known biocontrol agents that produce a variety of antibiotics. Peptaibols are a class of linear peptide antibiotics mainly produced byTrichoderma Alamethicin, the most studied peptaibol, is reported as toxic to plants at certain concentrations, while the mechanisms involved are unclear. We illustrated the toxic mechanisms of peptaibols by studying the growth-inhibitory effect of Trichokonin VI (TK VI), a peptaibol fromTrichoderma longibrachiatumSMF2, onArabidopsisprimary roots. TK VI inhibited root growth by suppressing cell division and cell elongation, and disrupting root stem cell niche maintenance. TK VI increased auxin content and disrupted auxin response gradients in root tips. Further, we screened theArabidopsisTK VI-resistant mutanttkr1tkr1harbors a point mutation inGORK, which encodes gated outwardly rectifying K(+)channel proteins. This mutation alleviated TK VI-induced suppression of K(+)efflux in roots, thereby stabilizing the auxin gradient. Thetkr1mutant also resisted the phytotoxicity of alamethicin. Our results indicate that GORK channels play a key role in peptaibol-plant interaction and that there is an inter-relationship between GORK channels and maintenance of auxin homeostasis. The cellular and molecular insight into the peptaibol-induced inhibition of plant root growth advances our understanding ofTrichoderma-plant interactions. PMID:26850879

  13. Dietary Arginine Requirements for Growth Are Dependent on the Rate of Citrulline Production in Mice123

    Science.gov (United States)

    Marini, Juan C; Agarwal, Umang; Didelija, Inka C

    2015-01-01

    Background: In many species, including humans, arginine is considered a semiessential amino acid because under certain conditions endogenous synthesis cannot meet its demand. The requirements of arginine for growth in mice are ill defined and seem to vary depending on the genetic background of the mice. Objective: The objective of this study was to determine the metabolic and molecular basis for the requirement of arginine in 2 mouse strains. Methods: Institute of Cancer Research (ICR) and C57BL/6 (BL6) male mice were fed arginine-free or arginine-sufficient diets (Expt. 1) or 1 of 7 diets with increasing arginine concentration (from 0- to 8-g/kg diet, Expt. 2) between day 24 and 42 of life to determine the arginine requirements for growth. Citrulline production and “de novo” arginine synthesis were measured with use of stable isotopes, and arginine requirements were determined by breakpoint analysis and enzyme expression by reverse transcriptase-polymerase chain reaction. Results: In Expt. 1, ICR mice grew at the same rate regardless of the arginine concentration of the diet (mean ± SE: 0.66 ± 0.04 g/d, P = 0.80), but BL6 mice had a reduced growth rate when fed the arginine-free diet (0.25 ± 0.02 g/d, P < 0.001) compared to the 8-g arginine/kg diet (0.46 ± 0.03 g/d). ICR mice showed at least a 2-fold greater expression (P < 0.001) of ornithine transcarbamylase (OTC) than BL6 mice, which translated into a greater rate of citrulline (25%) and arginine synthesis (49%, P < 0.002). In Expt. 2, breakpoint analysis showed that the requirement for growth of BL6 mice was met with 2.32 ± 0.39 g arginine/kg diet; for ICR mice, however, no breakpoint was found. Conclusion: Our data indicate that a reduced expression of OTC in BL6 mice translates into a reduced production of citrulline and arginine compared with ICR mice, which results in a dietary arginine requirement for growth in BL6 mice, but not in ICR mice. PMID:25855119

  14. Comparison of Fatigue Properties and Fatigue Crack Growth Rates of Various Implantable Metals

    Directory of Open Access Journals (Sweden)

    Yoshimitsu Okazaki

    2012-12-01

    Full Text Available The fatigue strength, effects of a notch on the fatigue strength, and fatigue crack growth rate of Ti-15Zr-4Nb-4Ta alloy were compared with those of other implantable metals. Zr, Nb, and Ta are important alloying elements for Ti alloys for attaining superior long-term corrosion resistance and biocompatibility. The highly biocompatible Ti-15Zr-4Nb-4Ta alloy exhibited an excellent balance between strength and ductility. Its notched tensile strength was much higher than that of a smooth specimen. The strength of 20% cold-worked commercially pure (C.P. grade 4 Ti was close to that of Ti alloy. The tension-to-tension fatigue strength of an annealed Ti-15Zr-4Nb-4Ta rod at 107 cycles was approximately 740 MPa. The fatigue strength of this alloy was much improved by aging treatment after solution treatment. The fatigue strengths of C.P. grade 4 Ti and stainless steel were markedly improved by 20% cold working. The fatigue strength of Co-Cr-Mo alloy was markedly increased by hot forging. The notch fatigue strengths of 20% cold-worked C.P. grade 4 Ti, and annealed and aged Ti-15Zr-4Nb-4Ta, and annealed Ti-6Al-4V alloys were less than those of the smooth specimens. The fatigue crack growth rate of Ti-15Zr-4Nb-4Ta was the same as that of Ti-6Al-4V. The fatigue crack growth rate in 0.9% NaCl was the same as that in air. Stainless steel and Co-Cr-Mo-Ni-Fe alloy had a larger stress-intensity factor range (ΔK than Ti alloy.

  15. Effect of growth hormone on small intestinal homeostasis relation to cellular mediators IGF-I and IGFBP-3

    Institute of Scientific and Technical Information of China (English)

    Betul Ersoy; Kemal Ozbilgin; Erhun Kasirga; Sevinc Inan; Senol Coskun; Ibrahim Tuglu

    2009-01-01

    AIM: To evaluate the effects of growth hormone (GH) on the histology of small intestines which might be related to the role of insulin like growth factor (IGF)-I, IGF-binding protein 3 (IGFBP-3) and its receptors.METHODS: Twelve week-old adult male Wistar albino rats were divided into two groups.The study group ( n = 10), received recombinant human growth hormone (rGH) at a dose of 2 mg/kg per day subcutaneously for 14 d and the control group ( n = 10) received physiologic serum.Paraffin sections of jejunum were stained with periodic acid shift (PAS) and hematoxylin and eosin (HE) for light microscopy.They were also examined for IGF-I, IGFBP-3 and IGF-receptor immunoreactivities.Staining intensity was graded semi-quantitatively using the HSCORE.RESULTS: Goblet cells and the cells in crypt epithelia were significantly increased in the study group compared to that of the control group.We have demonstrated an increase of IGF-I and IGFBP-3 immunoreactivities in surface epithelium of the small intestine by GH application.IGF-I receptor immunoreactivities of crypt, villous columnar cells, enteroendocrine cells and muscularis mucosae were also more strongly positive in the study group compared to those of in the control group.CONCLUSION: These findings confirm the important trophic and protective role of GH in the homeostasis of the small intestine.The trophic effect is mediated by an increase in IGF-I synthesis in the small intestine, but the protective effect is not related to IGF-I.

  16. Correlation of the Growth Rate of the Hydrate Layer at a Guest/Liquid-Water Interface to Mass Transfer Resistance

    Directory of Open Access Journals (Sweden)

    Ryo Ohmura

    2012-01-01

    Full Text Available Growth rate of a hydrate layer at the guest/liquid-water interface is analyzed considering the conjugate process of the mass-transfer and hydrate crystal growth. Hydrate-layer growth rate data in the literature are often compiled according to the system subcooling (∆T ≡ Teq − Tex, where Teq is the equilibrium dissociation temperature of the hydrate and Tex is the system temperature, suggesting predominant heat transfer limitations. In this paper, we investigate how the existing data on hydrate-layer growth is better correlated to mass transfer of the guest species in liquid water in three-phase equilibrium with bulk guest fluid and hydrate. We have analyzed the conjugate processes of mass-transfer/hydrate-layer-growth following our previous study on the hydrate crystal growth into liquid water saturated with a guest substance. A dimensionless parameter representing the hydrate-layer growth rate is derived from the analysis. This analysis is based on the idea that the growth rate is controlled by the mass transfer of the hydrate-guest substance, dissolved in the bulk of liquid water, to the front of the growing hydrate-layer along the guest/water interface. The variations in the hydrate-layer growth rate observed in the previous studies are related to the dimensionless parameter.

  17. Growth Rate and Relocation Movements of Common Nighthawk (Chordeiles minor) Nestlings in Relation to Age

    Science.gov (United States)

    Kramer, Gunnar R.; Chalfoun, Anna D.

    2012-01-01

    Relocation by dependent young is a survival strategy that occurs among a wide range of taxa. The Common Nighthawk (Chordeiles minor) lays its eggs on bare substrate and, once hatched, nestlings may relocate to new sites daily. We located and monitored eight Common Nighthawk nests in Grand Teton National Park, Wyoming, quantified inter-use-site distances in relation to nestling age, and calculated a nestling growth rate curve. Common Nighthawk nestlings grow in a nearly linear fashion. Nestlings moved up to 48 m in a single day and larger, older nestlings tended to move greater distances between daily use-sites.

  18. Growth Rates and Responsiveness of Credit to the Changes in Deposits in the Indian Banking

    Directory of Open Access Journals (Sweden)

    M. Upender

    2013-02-01

    Full Text Available An attempt has been made in the present paper to examine the Growth Rates of Deposits, Credit Extended and Responsiveness of the Credit Extended to the Changes in the Deposits for both the Pre and Post - Globalization Periods in India using the time series data. The analysis based on the regression results show that the numerical values of the elasticity of the credit extended with respect to deposits for different banks under consideration are more than unity during post-globalization period showing elastic nature of the credit extended.

  19. The Chicago monetary growth-rate rule: Friedman on Simons reconsidered

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    G.S. TAVLAS

    2013-12-01

    Full Text Available The work takes up a series of issues pertaining to the monetary interpretation of Friedman and Simons. The authors find that espousal of a monetary rule involves, foremost, confidence in the extrapolability of long-term statistical trends, particularly with respect to velocity. The initial formulation of the monetary hypothesis of the Great Depression is linked to an entirely overlooked original contribution by William Foster and Waddill Catchings. Their contribution these authors essentially anticipates views set forth by Friedman and Simons, and already included the formulation of the monetary growth-rate rule.  

  20. Measurements of coherent tune shift and head-tail growth rates at the SPS

    CERN Document Server

    Arduini, Gianluigi; Cornelis, K; Papaphilippou, Y; Zimmermann, Frank; Zorzano-Mier, M P; CERN. Geneva. SPS and LEP Division

    1999-01-01

    Measurements of the coherent tune shifts with intensity and of head-tail growth rates have been performed with single proton bunches in the SPS, at 26 Gev. From these measurements, the real and imaginary part of the transverse impedance can be estimated. Together with earlier and future measurements, this will be used to experimentally document and follow up the effect of the impedance improvements on the SPS as injector for the LHC. A reproducibility at the 20% level was achieved for the value of the effective vertical impedance inferred from the coherent tune-shit measurements.